Monomeric polysiloxanes end-capped with activated unsaturated groups are copolymerized with acrylic acid to form hydrophilic, water absorbing polysiloxane contact lenses. These contact lenses are unexpectedly capable upon hydration of retaining from 1 percent to about 99 percent by weight, based upon the total weight of the copolymer, of water.

1. Field of the Invention
It was discovered that the hydrophobic properties of certain polysiloxanes could be altered through copolymerization with acrylic acid to form a copolymer which unexpectedly possessed water absorbing properties sufficiently that when the copolymer was saturated with water the copolymer retained from about 1 percent to about 99 percent by weight, based on the total weight of the copolymer, of water.
The instant contact lenses comprise water absorbing hydrophilic, flexible, fillerless, hydrolytically stable, biologically inert, transparent contact lenses which have the capability of transporting oxygen sufficiently to meet the requirements of the human cornea. These lenses comprise a polysiloxane monomer .alpha.,.omega. terminally bonded through divalent hydrocarbon groups to polymerized, free radical polymerizably activated, unsaturated groups copolymerized with acrylic acid forming a polymer in a crosslinked network capable upon saturation with water of retaining from about 1 percent to above 99 percent by weight, based on the total weight of the polymer, of water.
2. Prior Art Statement
U.S. Pat. No. 4,153,641 teaches contact lenses made from polymers and copolymers comprising poly(organosiloxane) polymers and copolymers formed by polymerizing a poly(organosiloxane) monomer .alpha.,.omega. terminally bonded through divalent hydrocarbon groups to polymerized, free radical polymerizably activated, unsaturated groups forming a polymer in a cross-linked network. Additionally, specific comonomers are disclosed which include lower esters of acrylic and methacrylic acid, styryls and N-vinyl pyrrolidinone which may be copolymerized with the above described poly(organosiloxane) monomer to form a copolymer. The instant invention preferred polysiloxane monomers include the same poly(organosiloxane) monomers described above. However, it was unexpectedly discovered that when the poly(organosiloxane) monomers described above were copolymerized with acrylic acid a water absorbing polysiloxane copolymer was formed. This copolymer is extremely suitable for making hydrophilic, water absorbing, soft contact lenses. It is generally known in the siloxane art that siloxanes are hydrophobic. There are a few instances where the art teaches hydrophobic polysiloxanes. We know of only one instance, in addition to the instant invention, where a polysiloxane is disclosed which is capable of absorbing water. However, this known material as disclosed in U.S. Pat. No. 4,136,250 would not be suitable for making the instant contact lens for the reasons stated herein concerning U.S. Pat. No. 4,136,250 as prior art. As mentioned, unexpectedly it was discovered that when the instant polysiloxanes were copolymerized with acrylic acid that not only was the resulting copolymer hydrophilic but when the copolymer was saturated with water this copolymer unexpectedly absorbed from about 1 percent to about 99 percent by weight, based on the total weight of the copolymer, of water.
U.S. Pat. No. 4,136,250 teaches in pertinent part, a water absorbing polysiloxane which may be used to make soft contact lenses which is obtained by copolymerizing the following siloxane monomer: ##STR1## with a variety of hydrophilic monomers including acrylic acid. The above siloxane monomers can be reduced to a formula similar to but yet critically different from the instant polyorganosiloxane monomers. From the pertinent teachings of U.S. Pat. No. 4,136,250 the following siloxane monomer may be derived: ##STR2##
The oxygen atom in the monomer backbone with the arrow pointing to it is present in the '250 formula but not present in the instant polyorganosiloxane monomers. This oxygen atom presents several problems. This particular oxygen atom, because of its placement between the silicone and carbon atoms, is subject to hydrolysis and alcoholysis. This stability is important if this material is to be used for biomedical devices, such as contact lenses, since these types of devices are usually heated in order to disinfect them. If, during heating the contact lens loses it shape, then it loses its optics. This means that the material taught in '250 would be undesirable for use in certain medical devices including contact lenses. The instant polyorgansiloxane monomers result in copolymers which have superior hydrolytic stability since there is no Si-O-C linkage.
Also to be considered are the examples of '250. Only in these examples of '250 are there specific monomers disclosed without this undesirable Si-O-C linkage. However, these specific monomers have undesirable urethane linkages or couplings which present structures which are even more different from the instant monomers. The urethane linkages, i.e., ##STR3## is as mentioned, also undesirable for use in medical devices, particularly contact lenses. However, in addition, the instant polyorganosiloxane monomers have no urethane linkages.
U.S. Pat. No. 4,138,382 teaches, in pertinent part, a hydrophilic, water swellable, crosslinked copolymer gel. This copolymer gel is a hydrogel, such as N-vinylpyrrolidone crosslinked with a low molecular weight siloxane. The siloxane component is a very small constituent and is present for the purpose of crosslinking. The siloxane is not present in amounts more than about 2 percent by weight. This does not teach a hydrophilic, water absorbing siloxane, much less, a contact lens made therefrom.
Dutch Pat. No. 7,704,136 published Oct. 18, 1977 teaches, in pertinent part, a wettable siloxane material for use in making contact lenses. However, '136 teaches that the wettable contact lenses should not absorb water since water absorption, as taught in '136, would cause water to be discharged into the eye when the contact lenses are in use. This is viewed as a disadvantage in '136. The instant invention concerns a polysiloxane contact lens which absorbs water in larger amounts. Water absorption is viewed by the instant inventors as an advantage. The Dutch reference '136 further teaches that a lens should not absorb water since, as taught in '136, such a lens would undergo changes, such as, changing its optical properties. '136 further teaches that the handling of such a lens is difficult because when it is swellable it is physically weak. However, the instant lenses are made from wettable polysiloxane material which is strong, durable, water absorbing and oxygen permeable. The Dutch patent further refers to some of the monomers which may be reacted with the polysiloxanes taught in '136 which are esters of glycidyl alcohol and esters of certain acids including acrylic acid and methacrylic acid. '136 also suggests the use of specific anhydrides such as maleic anhydride. Nowhere does this Dutch reference '136 disclose the instant polysiloxanes or that acrylic acid may be reacted with these monomeric siloxanes in order to form the instant water absorbing copolymer as disclosed herein.
U.S. Pat. No. 3,808,178 discloses, in pertinent part, a polymeric material containing a polymethacrylate backbone with relatively short poly(organosiloxane) ester side chains on the backbone polymer. There is no crosslinking involved in '178 since the monomers disclosed in '178 are monofunctional, i.e., have only one functional group on each monomer. In order to get crosslinking in '178 it is taught at column 5 of '178 that different monomers must be added for crosslinking which have more than one functionality. However, in the instant invention crosslinking is obtained since each siloxane monomer is difunctional, i.e., each siloxane monomer contains two functional groups, most preferably two methacrylate groups which results in crosslinking. Not only does '178 not teach the polysiloxanes monomers used in the instant invention but '178 does not remotely teach making the instant hydrophilic siloxane which is also water absorbing for use as soft, hydrophilic, water absorbing contact lens.
Katz and Zewi, "Correlations Between Molecular Structure and Some Bulk Properties of Highly Crosslinked Polysiloxane", J. Polymer Sci., Vol. 46, pages 139-148 (1974) teaches, in pertinent part, that divinyl monomers can be prepared by esterification of the carboxyl-terminated compounds with two molecules of a monoester of ethylene glycol and a monoester of acrylic acid. Polymerization can be effected by ultraviolet radiation at room temperature. Also taught is the structure as shown on page 146 of the Katz et al article. If this formula was broken down as it relates to the preferred siloxane comonomers taught in the instant application, the formula would be as follows: ##STR4##
In the above formula the R group has an ester linkage whereas in the instant preferred siloxane comonomers the R is a hydrocarbon group.
Also in the above formula the center repeating unit is a dimethyl siloxane unit whereas the center repeating unit in the instant preferred siloxane comonomers is a poly (organosiloxane) repeating unit as illustrated below. The R linkage in the Katz et al paper is not as hydrolytically stable as the hydrocarbon linkage in the instant preferred siloxane comonomers. The ester group in Katz et al can be hydrolyzed. This stability is important if this material is to be used in soft contact lenses or biomedical devices since these types of devices are usually heated in order to disinfect them. As mentioned, if the contact lens loses its shape, then it loses its optics. It should be understood that the instant preferred polysiloxane comonomers to have an ester linkage. However, this linkage is between the A and the R groups. It is actually located in the A group as illustrated below by a formula of one of the most preferred monomeric siloxanes of the instant invention. ##STR5##
This Katz et al reference, in addition to teaching the specific formula on page 146, merely teaches that phase differences are detectable as the siloxane chain length is decreased. As the siloxane chain increases in length, Katz et al teaches that the phase differences are lost and these differences merge into one continuous transition.
In addition to the above, it is important to note that Katz et al does not suggest any usage for this material.
Katz and Zewi "Some Rheological Properties of Highly Crosslinked Polysiloxanes" J. Polymer Sci., Vol. 13, pages 645-658 (1975) teaches, in pertinent part, the same materials as taught in the above cited (1974) article by Katz et al. This article teaches in more detail the steps necessary in order to make the starting materials for the polymer as taught in the '74 article. Katz et al is teaching in this article, in pertinent part, how to synthesize the carboxyl terminated siloxane. This is illustrated in pages 646-647. Katz et al then crosslinks this using a different chemical reaction than in the instant application in order to make the polymer as shown on page 649. This polymer is not related in any way to the instant materials. In addition to the above, it is important to note that this Katz et al reference also makes no mention of any uses of the material.
Katz and Zewi "Microheterogeneity in Crosslinked Polysiloxane" J. Polymer Sci., Polymer Chemistry Edition, volume 16, pages 597-614 (March, 1978) teaches, in pertinent part, the same materials as taught in the above cited (1974) and (1975) articles by Katz et al. The only new material mentioned appears on page 598, line 8, i.e., crosslinked polyesters. However, these crosslinked polyesters are not pertinent to the instant application. Katz et al is teaching in this article, in pertinent part, how to prepare certain monomers. Katz et al is merely suggesting the same crosslinked material as he suggested in his earlier (1974) and (1975) articles. Katz et al then discusses the physical properties and the microheterogeneity of these crosslinked polymers. He discusses the difference in the phase separation on the submicroscopic scale. As to the physical properties, which Katz et al mentioned in his article on page 597, he discusses the physical properties in general of polysiloxanes. Katz et al discusses specific properties of his polymers at page 609 where he presents modulus-temperature data. Then he discusses crosslinking efficiency on page 607. He is measuring properties which will give him an idea of his efficiency of crosslinking. Again, it should be stated that Katz et al in this (1978) article teaches no more material than he taught in his earlier articles except for the disclosure of the crosslinked polyesters on page 598. However, these materials are not relevant to the instant application. In addition to the above, it is important to note that this Katz reference also makes no mention of any uses of this material except as possible sealants.
W. A. Piccoli, G. G. Haberland and R. L. Merker, J. Am. Chem. Soc. "Highly Strained Cyclic Paraffin-Siloxanes", vol. 82, p. 1883-1885 (Apr. 20, 1960) teaches, in pertinent part, the preparation of the cyclic paraffin-siloxane monomers which may be used in the instant invention to make the instant preferred siloxane prepolymers. These preferred siloxane prepolymers, i.e., linear monomers, in the instant invention are then copolymerized and crosslinked to form the preferred polymers used for making contact lenses. It is disclosed on page 1884, column 2, lines 15-27, of the above article that these cyclic paraffin-siloxane monomers may be polymerized using strong acids or bases to form linear polymers. The preferred siloxane linear polymers, as mentioned, are used in the instant invention as preferred prepolymers and copolymerized and crosslinked to form materials for making contact lenses. Nowhere does the article disclose or suggest the crosslinked water absorbing polysiloxane copolymers of the instant invention.
R. L. Merker and M. J. Scott J. of Polymer Sci., "The Copolymerization of Cyclic Siloxanes" Vol. 43, p. 297-310 (1960) teaches, in pertinent part, copolymerization studies using cyclic alkyl siloxanes. These materials are copolymerized with silethylene siloxane and then the rates of polymerization are determined. The silethylene siloxane is used because it does not equilibrate between the ring form and the linear form. Once the ring form is broken the ring stays open, that is, the reaction is kept going in one direction. The crosslinked polymers of the instant invention are not suggested or taught by this article nor is the use of these polymers as contact lenses taught or suggested.
U.S. Pat. Nos. 3,041,362 and 3,041,363 teach, in pertinent part, the same materials as taught in the above mentioned articles coauthored by Merker in the J. Am. Chem. Soc. and J. of Polymer Sci. However, in addition, it is taught that some polyfunctional siloxanes may be used with certain monomers to give crosslinked polymers and copolymers. However, the crosslinked copolymers of the instant invention are not taught or suggested by these references. Furthermore, it is not taught or suggested by these references that these polymers could be used as contact lenses.
E. E. Bostick, "Cyclic Siloxanes and Silazanes", Chapter 8, p. 343-357, Kinetics and Mechanisms of Polymerization, Vol. 2, Frisch and Regan ed., (1969) teaches, in pertinent part, siloxane polymerization using cyclic siloxanes. This article teaches no more than the above mentioned article from J. of Polymer Sci. by R. L. Merker and M. J. Scott.
E. E. Bostick, Chemical Reactions of Polymers, High Polymers series vol. 19 (1964) E. M. Fettes, ed. chapter 7 "Interchange Reactions" section B "Silicones" p. 525 teaches, in pertinent part, siloxane copolymerization using cyclic siloxanes. It teaches that these reactions go in one direction. This article teaches no more than the above mentioned article from J. of Polymer Sci. by R. L. Merker and M. J. Scott.
U.S. Pat. No. 2,770,633 discloses 1,3-bis(4-methacryloxybutyl) tetramethyl disiloxane, one of the preferred siloxane monomers used in the instant invention. This is taught at column 1, line 63 of '633 when R equals vinyl. However, '633 teaches only the siloxane monomer whereas the instant invention teaches not only the siloxane monomers but the copolymer made from copolymerization of the polysiloxane monomer with acrylic acid to form a hydrophilic, water absorbing polysiloxane material for use in making soft contact lenses. '633 would not want the monomer disclosed in '633 to polymerize since it would not perform its intended function as a lubricant if polymerized.
U.S. Pat. Nos. 3,996,187, 3,996,189, 3,341,490 and 3,228,741 disclose, in pertinent part, contact lenses fabricated from poly(organosiloxanes) containing fillers. The tear strength and tensile strength of the contact lenses made from the instant polymer are of sufficient strength so that no fillers are required.
U.S. Pat. Nos. 3,996,187 and 3,996,189, as mentioned above, disclose contact lenses made from reinforced polysiloxanes. The lenses contain various polysiloxanes with index of refractions similar to the silica filler so that an optically clear silica filled silicone elastomer can be formed from aryl and alkyl siloxanes. The material contains from 5 to 20 percent silica. The silica is used, as mentioned, for strength. The instant invention contains no fillers for strength since the instant material has sufficient strength without fillers.
U.S. Pat. No. 3,341,490 discloses contact lenses made from blends of siloxane copolymers containing reinforcing silica fillers. As mentioned, the contact lenses of the instant invention contain no fillers.
U.S. Pat. No. 3,228,741 discloses contact lenses made from silicone rubber, particularly hydrocarbon substituted polysiloxane rubber. This silicone material contains fillers such as pure silica to control flexibility, pliability and resiliency of the lenses. The instant polymers require no fillers.
U.S. Pat. No. 3,518,324 teaches vulcanizing to make silicone rubber whereas the instant invention is concerned with contact lenses made from polymerizing specific monomers.
U.S. Pat. No. 3,878,263 teaches one configuration which may be ##STR6## Rs may be monovalent hydrocarbons. R' may be a monovalent hydrocarbon.
c may equal zero but when c equals zero then at least one Z must be OR"". PA0 Z is an important ingredient since this is used to crosslink the chains. Therefore, the monomers of the instant invention are not taught in '263.
U.S. Pat. No. 2,906,735 teaches a reaction between an alkyl siloxane and acrylic acid or a methacrylic acid resulting in a disiloxane terminated by acrylate groups. '735 does not teach the water absorbing copolymers of the instant invention.
U.S. Pat. No. 2,922,807 discloses disiloxanes having acryloxy or methacryloxy groups attached to the silicone through a divalent alkylene radical of from 2 to 4 carbon atoms.
U.S. Pat. No. 3,763,081 discloses, in pertinent part, the polymerization of an unsaturated siloxane which is somewhat difficult to polymerize since a double bond in this type of monomer generally is not very active. One must use both high temperatures and a peroxide catalyst or a platinum catalyst in order to complete this type of reaction. See, for example, '081 at column 4 lines 35-46. In the instant preferred reaction the monomeric materials are referred to specifically as having activated unsaturated groups bonded through a divalent hydrocarbon group to the siloxane whereas '081 has no activated unsaturated groups bonded to the siloxane.
U.S. Pat. No. 2,865,885, in pertinent part, teaches a vinyl group which is not activated as shown in column 1, lines 25-30 of '885. The reason '885's double bond is not "active" in the sense as defined in the instant application is that the double bond is bonded to either sulfur or oxygen. In the instant invention this same position would have a ##STR7## carbonyl group. This would make the double bond active as defined in the instant application. Therefore, '885 since the reactivity ratios are so different, i.e., the double bond is not active in '885 as defined in the instant invention, it would be very difficult to get an acceptable copolymerization reaction using the formulae of '885 as compared to the active double bond in the instant siloxane monomers which are easily copolymerized. In the instant invention the vinyl groups are "activated" to facilitate free radical polymerization. The formula given at column 1, lines 25-30 of '885 does not lend itself to free radical polymerization due to the lack of resonance but rather it lends itself to ionic polymerization due to the polar nature of the substituents. Therefore, it would be extremely difficult, if at all possible, for '885 to form the compounds of the instant invention. Also, the compounds formed in '885 are not hydrolytically stable because of the presence of the silicone-nitrogen bond in the formula. The instant invention cannot use a hydrolytically unstable compound. Furthermore, the products of this hydrolysis in '885 could be injurious to the human eye particularly the amines. Also, at column 3 of '885 the linkage is an amine linkage to the double bond and in the instant invention this linkage is always an alkyl. Therefore, '885 does not teach the instant siloxane monomers much less the instant water absorbing copolymers.
U.S. Pat. No. 2,793,223 teaches, in pertinent part, at Example 5 at column 3, lines 30-41 that a phenyl group is attached to the siloxane. Therefore, that material would be very hard and opaque. This would be unsuitable for contact lenses which must be transparent. Furthermore, contact lenses made from the polymers made from the monomers disclosed in '223, because of the presence of the phenyl group on the siloxane as shown in Example 5 of '223, would not transport oxygen sufficiently whereas contact lenses made from the instant polymers would transport oxygen sufficiently to meet the oxygen requirements of the human cornea.

Water absorbing contact lenses made from polysiloxane/acrylic acid polymer


A lockable security container for the transportation of valuables and including means for damaging valuables positioned within the container comprising: a container including an internal space for positioning valuables, means for damaging the valuables positioned within said internal space including a housing positioned within said internal space for containing a dye; said housing including a plunger interposed between a charge of powder and said dye; said charge of power being operatively connected to said container to activate said charge when said container is subjected to unauthorized tampering, activation of said charge moves said plunger against said dye to uniformly spray said internal space and damage said valuables.

To transport the day's takings, consisting of banknotes and the like, from shops to the night safe of a bank, it is a known practice to use simple leather bags or plastic tubes ("cartridges"). Both cartridges and night safes are very unsatisfactorily designed from the point of view of security, and a criminal today has many opportunities of obtaining the valuable contents in a variety of ways. Bank messengers are frequently attacked, as the cartridges are all too easily rifled of their contents, and the safes can be either blasted open or pulled out of the wall. Similarly a vehicle, may be broken open and emptied. Moreover, attacks on bank messengers and night-safe robberies have recently shown a marked tendency to increase, and the police, the Swedish Bank Inspection Board, and other institutions are desperately seeking for ways of overcoming the security problems. To this end, efforts are being made to improve existing arrangements, efforts which are mainly concentrated on strengthening the night safes in various ways. Experiments have also been made with systems whereby the valuables are dyed if the night safe is subjected to violence. Hitherto it has not been possible to make cartridges of such secure construction that they lose their attraction as objects of theft.
As a result of all the difficulties in the way of protecting valuables, the Swedish Bank Inspection Board is seriously considering measures which would involve restrictions on the services offered by banks, and which would naturally be to the disadvantage of the public.


A disclosed process uses ceramic fiber fabrication technology and allows for novel composite designs, including composites with different polarizable material regions and composites with a gradient in volume fraction of polarizable material. Moreover, composites with fine-scale microstructures may be formed. The new forming method is an improvement to the traditional "dice and fill" technique currently being utilized to form piezoelectric composites.

Transducers, such as those employed in the medical ultrasound imaging industry, typically employ piezoelectric ceramic materials such as lead-zirconate-titanate (PZT) to both emit and receive ultrasound waves. In recent years, however, composites have become the focus of piezoelectric research and development. Composite piezoelectric materials, typically combinations of polymers and ceramics, can increase the desired properties of the transducer while virtually eliminating the inherent weaknesses of the individual materials. A ceramic-polymer piezoelectric composite for example, retains a high piezoelectric coefficient and moderate dielectric loss which is characteristic of a typical piezoelectric ceramic, while decreasing the overall density and brittleness of the transducer. Moreover, polymers allow for flexibility and shape variability in the final composite. As a result, the properties of such composites are far superior to those of bulk ceramics or piezoelectric polymers alone.
Composite piezoelectric transducers, and methods for their production, are described, for example, in Composite Piezoelectric Transducers; R. E. Newnham et al; Materials in Engineering, Vol. 2, December 1980, 93-106, which is incorporated herein by reference.
Piezoelectric composites typically consist of a polarizable phase embedded in a non-polarizable material. These composites have many advantages over traditional monolithic piezoelectric ceramics including: (i) lower densities resulting in acoustic impedances closer to those of the human body, water, etc., eliminating the need for an acoustic matching layer, (ii) low dielectric constants, resulting in high piezoelectric voltage constant g, and (iii) ease of conformability to the shape of the backing material of the composite.
Two composite designs that have been particularly successful are composites with 2--2 and 1-3 connectivity. In these designs, the piezoelectric or polarizable phase is aligned in the poling direction of the composite (in a matrix of a suitable polymer.) In the case of the 2--2 composite, both the ceramic and polymer phases are two-dimensionally connected throughout the composite. The stiff ceramic phase supports most of the stress applied in the direction of its alignment, yielding a high piezoelectric charge coefficient d.sub.33, while the composite maintains a low density and dielectric constant.
In the 1-3 composite, the ceramic phase is one-dimensionally connected through the composite, while the polymer phase is three-dimensionally connected. For certain applications, the 1-3 composite yields superior properties to those described above for the 2--2 composite due to the lower density and lower dielectric constant. Connectivity, including types 1-3 and 2--2, are described in detail in Composite Piezoelectric Transducers; R. E. Newnham et al; Materials in Engineering, Vol. 2, December 1980, pages 93-106, which is incorporated herein by reference.
A common and convenient method for making 2--2 and 1-3 composites is to start by cutting parallel slots into a monolithic piezoelectric ceramic block. The slots are then filled with a polymer. Typically, this polymer filler is non-polarizable. If one set of parallel slots are cut, the resulting composite has a 2--2 connectivity. If a second set of parallel slots are cut orthogonally to the first set of slots and backfilled with a filler material, the resulting composite has a 1-3 connectivity. Transducer fabrication continues by grinding the unslotted section of the monolithic ceramic away from the slotted section, lapping the two sides parallel to one another, and electroding the surfaces containing exposed ceramic. The resulting structure essentially comprises a semiflexible mat consisting of strips, posts or rods of piezoelectric material laterally encased by polymeric matrix material such as epoxy.
A strong electric field is then applied to the composite in a direction perpendicular to the plane of the polarizable sheet using conventional poling or corona discharge techniques. The intensity of the electric field used will ordinarily be selected to provide efficient polarization. However, it will be kept below the range at which substantial dielectric breakdown of the material being polarized occurs. The aforementioned method is known as the "dice and fill" method and is described in PZT-Epoxy Piezoelectric Transducers: A Simplified Fabrication Procedures, H. P. Savakus et al; Materials Research Bulletin, Vol. 16, 1981, pages 677-680, which is incorporated herein by reference.
Although, as mentioned above, piezoelectric composites typically consist of a polarizable phase embedded in an non-polarizable phase, there is a need to develop efficient manufacturing method for production of composites having multiple polarizable and/or non-polarizable phases. Also, there is a need to develop more efficient methods for the manufacture of piezoelectric composites having decreased size and/or periodicity of the polarizable phase or phases. Composites having these properties have been identified as a key area of transducer development.
Some examples of these needs are evidenced in the field of medical imaging. The resolution of imaging systems can be enhanced by increasing the frequency of the generated sound wave from the transducer. To increase the frequency of the sound wave, the size and periodicity of the polarizable phase in the composite must be decreased. In addition, enhanced pulse-echo properties are realized if the transducer contains transmitting and receiving sections wherein the transmitting sections contain an polarizable phase with high transmitting sensitivity, while the receiving sections contain a polarizable phase with high receiving sensitivity.
Moreover, there has been a drive to create so-called "smart" materials. Smart materials are described in "Smart Ceramics"; Newnham et al., Ferroelectrics, Vol. 102, pp. 259-266 which is incorporated herein by reference. A smart material senses a change in the environment, and using a feedback system, makes a useful response. It may be both a sensor and an actuator. A very smart material can tune its sensor and actuator functions in time and space to optimize behavior. Tuning of a very smart material can be accomplished by using a multitude of polarizable phases.
Finally, it would be desirable to have an efficient method to tailor the piezoelectric properties within a single transducer by varying the ceramic volume content across the device. This reduces the out of plane distortions of the transmitted signal.
The "dice and fill" method has several limitations in meeting the above stated needs. Dicing technology utilizes thin, diamond coated blades rotating at high speeds. The blades, often thinner than 200 microns, are expensive, difficult to handle, and have short usage lives. Moreover, the "dice and fill" technique uses monolithic ceramics, ruling out the possibility of composites with multiple polarizable ceramic phases. Finally, varying the ceramic volume content across the transducer would require frequent changes of dicing blades to vary the thickness of the slots, substantially adding to the time it takes to produce a transducer.

Mehtod for making piezoelectric composites


In one embodiment, a computer-implemented method comprises receiving, at a server computer, a plurality of commit records of a source code management system (SCM), wherein a first commit record of the plurality of commit records includes a first parent commit identifier (ID) that identifies a parent commit record of the first commit record; storing, in one or more data repositories, a full commit record for each commit record of the plurality of commit records; in response to determining that the first commit record includes a parent commit ID, storing, in the one or more data repositories, a first partial commit record for the first commit record, wherein the first partial commit record comprises a partial commit record that is identified by the first parent commit ID; generating and submitting a database query to a digital data repository associated with the SCM, based on determining that a partial commit record is stored in the one or more digital repositories, and receiving first partial commit update data for the first partial commit record; updating, based on the first partial commit update data, one or more fields of the first partial commit record to convert the first partial commit record into an updated commit record, wherein the updated commit record comprises a full commit record.

The approaches described in this section are approaches that could be pursued, but not necessarily approaches that have been previously conceived or pursued. Therefore, unless otherwise indicated, it should not be assumed that any of the approaches described in this section qualify as prior art merely by virtue of their inclusion in this section.
An issue tracking system (ITS) is a system used to manage work items or "issues". Example ITSs include JIRA, JIRA Service Desk and JIRA Software which are commercially available from Atlassian Pty Ltd., Sydney, Australia. ITSs are deployed in a wide variety of applications including organizational customer support call centers and for software development teams to use in project management and bug tracking. When deployed for software development projects, an ITS may be used with other systems, such as source code management (SCM) systems (also known as 'revision control' or 'version control systems'). These are used to track and manage computer program source code as the code is written and revised. Although SCM systems are predominantly used to track source code they can be used to track other data.
Examples of SCM systems include systems such as MERCURIAL, GIT and Bitbucket (commercially available from Atlassian Pty Ltd). Generally speaking, SCM systems store data—typically source code—in repositories and facilitate access to that data from multiple different client systems. In order to work on a project, a user (using a client system) creates a local copy of the relevant data (e.g. program source code) from a repository and works on that local copy. If the user makes changes that are to be incorporated into the remote version of the data, the user's local copy of the data—or at least those portions that have been changed—is written back to the repository using the SCM system. The SCM system controls access to the repository data and also manages version control for the data.
SCM systems typically manage and track numerous documents/source code files across multiple repositories and for numerous users. These documents/files managed by SCM systems can be changed frequently as users add new documents/files, delete documents/files, and make changes to existing documents/files.
ITSs and SCMs are separate systems that provide independent functionality. In certain cases, they can be integrated and communicate with each other. Data may be shared and synchronized between systems, allowing information from one system to be linked with and displayed on the other system.
Synchronizing data between and ITS and SCMs requires processing large streams of data. Disruptions in synchronization processes often occur and can be caused by network issues, outage of service of one of the ITS and SCMs, or bugs in code that is utilized by the synchronization procedures. Disruptions can lead to storing fragmented data and in some cases, wasting of compute resources by having to restart a synchronization process from the beginning.
Techniques are desired to effectively mitigate the effects of synchronization disruptions.

Efficient storage and analysis of source code modification history data


Heart valve assembly systems and methods configured for medical interventional procedures. In one aspect, the methods and systems involve a modular approach to treatment.

The present disclosure relates to medical interventional systems and methods and more particularly, to artificial valve assembly systems and methods. The long-term clinical effect of valve regurgitation is well recognized as a significant contributor to cardiovascular related morbidity and mortality. In particular, there are two basic classifications of mitral regurgitation ("MR"), primary and secondary. Primary MR results when there is either direct tissue pathology of the valve structures or there is structural damage/alteration of one or more valve structures (leaflets, chordae). Secondary MR is a functional loss of valve competence caused left ventricular dilatation, and secondary alteration of mitral valve geometry following damage to the myocardium and left ventricle ("LV") causing. Whether valvular in origin leading to a ventricular problem or of ventricular/muscle origin leading to the valvular problem, the effect of high levels of MR is significant on cardiopulmonary physiology, resulting in significantly elevated left atrial pressures and pulmonary pressures, pulmonary congestion, and volume and energy overload effects on the myocardium. This physiology creates significant heart failure symptoms of shortness of breath and decreased physical endurance, ultimately leading to death.
The decision to intervene on a regurgitant mitral valve relates to the level of mitral regurgitation, the symptoms of the patient as an indicator of progressive negative physiologic effect, and the functional status of the left ventricle, specifically ejection fraction. The risk of intervention is weighed against the benefit of MR treatment.
The mitral valve is a therapeutic target of intervention/surgery early in the disease process of primary valvular disease because of MR's deleterious effects on heart/ventricular function if left untreated. For patients with moderate-severe or severe levels of MR combined with even a modest decrease in ejection fraction ("EF"), or the development of symptoms, surgical correction is indicated. In this situation, the risk of surgery in what is an otherwise healthy patient is far outweighed by the beneficial effects of eliminating the long-term negative effects of MR.
A more difficult question has been the patient with secondary or functional mitral regurgitation. In this situation, the patient has pre-existing LV dysfunction combined with heart failure symptoms, and a developing/worsening level of MR. The risks of intervention in this scenario are much greater. The net benefit of surgically intervening to eliminate the MR has not been demonstrated. Symptomatic benefit has been seen, but not a net mortality benefit. Therefore, it is usually contemplated or applied concomitantly when a patient is undergoing coronary artery bypass graft CABG revascularization.
The classification of mitral regurgitation as primary or secondary is a useful to differentiate between the underlying disease processes that led to the incompetent valve. These provide a starting point that can direct the type and timing of an intervention. However, it is not sufficient to fully describe the issues that direct a therapeutic approach. Because the mitral valve is complex structurally, mechanically, and physiologically, a more detailed description and understanding of the abnormalities associated with mitral regurgitation is needed to direct existing therapies, as well as develop new options for therapy.
Pathologic abnormality of the mitral valve tissue is a common cause of primary mitral regurgitation. Typical pathologies that occur include rheumatic, myxomatous, endocarditis, and Marfan's or other collagen based tissue diseases. Calcification and leaflet thickening are also abnormalities associated with direct tissue level changes in the valve. These can be either part of a primary tissue based disease or result from a long-standing insult to the valve, including regurgitant jetting across the leaflets.
Congenital and acquired structural abnormalities like ruptured chordae, leaflet prolapse, fenestrations, and clefts can also be forms of primary valve disease leading to mitral regurgitation.
Functional MR results from myocardial damage leading to ventricular functional loss and geometric changes that impact the valve coaptation through associated annular dilatation and papillary muscle displacement. In pure functional MR, the valve structures are not pathologic nor have structural defects, but the geometric alteration leads to a loss of coaptation of the mitral valve leaflets, often in the central A2/P2 segment of the valve.
As with many multi-factorial clinical problems, one etiologic element (tissue pathology, structural alterations, functional/geometric changes) may lead to others resulting in a "mixed" picture. This is especially true with mitral regurgitation. In the case of primary MR of either tissue or structural origin, volume overload of the LV can create failure and LV dilatation creating a component of functional MR if the valve is left untreated. In the case of long standing functional MR, tissue changes can be seen such as calcification and thickening caused by the regurgitant jet and high leaflet stresses. Muscle/tissue damage to the myocardium in and around the sub-valvular apparatus can create structural alteration such as ruptured papillary muscles/chordae and prolapse. Excessive tenting of the leaflets associated with significant functional MR can also stress the chords causing rupture.
The net result is that MR is a spectrum disorder with many patients having a mixed picture of valve abnormalities. This is an important factor in the decisions surrounding a mitral valve therapeutic approach, specifically repair or replacement.
The primary goal of any therapy of the mitral valve is to significantly reduce or eliminate the regurgitation. By eliminating the regurgitation, the destructive volume overload effects on the left ventricle are attenuated. The volume overload of regurgitation relates to the excessive kinetic energy required during isotonic contraction to generate overall stroke volume in an attempt to maintain forward stroke volume and cardiac output. It also relates to the pressure potential energy dissipation of the leaking valve during the most energy-consuming portion of the cardiac cycle, isovolumic contraction. Additionally, successful MR reduction should have the effect of reducing the elevated pressures in the left atrium and pulmonary vasculature reducing pulmonary edema (congestion) and shortness of breath symptomatology. It also has a positive effect on the filling profile of the left ventricle and the restrictive LV physiology that can result with MR. These pathophysiologic issues indicate the potential benefits of MR therapy, but also indicates the complexity of the system and the need for a therapy to focus beyond the MR level or grade.
It is also desirable to prevent new deleterious physiology or function of the valve. The procedure and system used to fix the mitral valve needs to avoid worsening other (non-MR) existing pathologic conditions or creating new pathologic conditions as a result of the treatment of the critical factors to be managed is Stenosis/gradient. That is, if a valve system is used that does not allow for sufficient LV inflow without elevated filling pressures, then critical benefits of MR reduction are dissipated or lost. Moreover, Atrial fibrillation is to be avoided as it can result if elevated pressures are not relieved by the therapy, or are created by the system (high pressure results in atrial stress leading to dilatation ultimately leading to arrhythmias). Also, if the procedure results in damage to atrial tissue at surgery it can result in the negative physiologic effect of atrial fibrillation. Further, one should be aware of the possibility of increased LV Wall Stress (LV geometry). Due to the integral relationship of the mitral valve with LV geometry through the papillary and chordal apparatus, LV wall stress levels can be directly affected resulting in alterations of LV filling and contraction mechanics. Accordingly, a system that does not preserve or worsens the geometry of the LV can counter the benefits of MR reduction because of the alteration of contractile physiology.
It has been generally agreed that it is preferable if the valve can be repaired. Repair of valve elements that target the regurgitant jet only allows for minimal alteration to the valve elements/structures that are properly functioning allowing for the least potential for negatively effecting the overall physiology while achieving the primary goal. Native valve preservation can be beneficial because a well repaired valve is considered to have a better chance of having long standing durability versus a replacement with an artificial valve that has durability limits. Also, while current surgical artificial valves attempt chord sparing procedures, the LV geometric relationship may be negatively altered if not performed or performed poorly leading to an increase in LV wall stress due to an increase in LV diameter. Thus, while preferred and possible for technically competent surgeons, the relatively high recurrence rate of MR due to inadequate repair, the invasiveness of the surgery especially in sick or functional MR patients, and the complexities of a repair for many surgeons lead to a high percentage of mitral operations being replacement.
Conventionally, surgical repair or replacement of the mitral valve is performed on cardiopulmonary bypass and is usually performed via an open median sternotomy resulting in one of the most invasive high risk cardiac surgical operations performed, especially in subpopulations such as functional MR. Therefore, a key improvement to mitral valve operations is to significantly lower the risk and invasiveness, specifically utilizing a percutaneous or minimally invasive technique.
While there have been attempts to replicate existing surgical repair via less invasive surgical or percutaneous methods, given the complexity of repairing the valve surgically, the efforts have largely been deemed lacking adequate efficacy and have not altered the risk benefit ratio sufficiently to warrant ongoing investment, approval, or adoption. In particular, there has been a general technology failure due to the complexity of anatomy to percutaneously manage with an implant or implantable procedure. The broad spectrum of mitral disease directly influences outcomes with a resulting inability to match technology with pathology. There has also been observed inadequate efficacy with poor surgical replication and safety results. It has also been recognized that percutaneous approaches successful to certain valve procedures such as aortic valve replacement associated with a single pathology and a relatively circular rigid substrate, mitral valves often suffer from multiple pathologies and a flexible or elastic annular with multiple structures.
Accordingly, what is needed is an effective long lasting MR reduction without creating negative physiologic consequences to the cardio-pulmonary system (heart, lungs, peripheral vasculature) including stenosis, LV wall stress and atrial fibrillation. It is also desirable to be able to perform the operation in a reliable, repeatable, and easy to perform procedure and to have a broadly applicable procedure for both patients and physicians, while employing a significantly less invasive method.
The present disclosure addresses these and other needs.

This patent is subject to a terminal disclaimer.


The present disclosure provides an LED driver with brightness control and a driving method thereof, which adjust a first rate of a first current mirror, a second rate of a second current mirror, and a reference current of a current source according to the brightness to be presented (related to image brightness information) to adaptively adjust an LED current flowing through an LED string, thereby reducing the loss of the LED current during operation over an operating current range. Besides, the LED driver with brightness control and the driving method thereof do not require that an operator adjusts the variation of the LED current in different operating current ranges in advance, thereby reducing the test time and cost and avoiding the operator from deciding a wrong adjustment amount.

LEDs have been massively produced at present, and most of the LEDs are used for lighting and display. A plurality of LEDs can be connected in series to form one or more LED strings, and an LED driver drives the LED string to emit light. A conventional LED driver has varied structures, one of which is shown in FIG. 1. An LED driver 10 is coupled to an LED string 50, and drives the LED string 50 according to image brightness information Sbr. The LED driver 10 may control an LED current IL flowing through the LED string 50 according to different image brightness information Sbr (that is, different image brightness information Sbr corresponds to a different LED current IL), so as to control the brightness of the LED string 50. Because the brightness is controlled within a relatively wide operating current range, the image brightness information Sbr needs to be programmed also within a relatively wide range.
As shown in FIG. 1, the LED driver 10 includes an LED controller 11, a current source 13, a first current mirror 15, a second current mirror 17, and a drive transistor 19. The LED controller 11 receives the image brightness information Sbr, generates a digital code signal Code according to the image brightness information Sbr, and transmits the digital code signal Code to the current source 13, to adjust a reference current Iref flowing through the current source 13. Further, if the digital code signal Code is 8-bit data, the LED controller 11 converts the image brightness information Sbr into an 8-bit digital code signal Code, to adjust the reference current Iref flowing through the current source 13.
The first current mirror 15 generates a first current I1 according to the reference current Iref and a first rate K1 of the first current mirror 15. Subsequently, the second current mirror 17 generates the LED current IL flowing through the LED string 50 according to the first current I1 and a second rate K2 of the second current mirror 17. In addition, the LED controller 11 generates a pulse-width modulation (PWM) signal according to the image brightness information Sbr, to turn on/off the drive transistor 19. In this way, the LED string 50 is driven, and the brightness of the LED string 50 is controlled according to the LED current IL. It should be noted that, the LED current IL is equal to a product obtained by multiplying the reference current Iref, the first rate K1, and the second rate K2 together, where the first rate K1 multiplied by the second rate K2 is a constant.
Therefore, the first rate K1 and the second rate K2 are nonadjustable constants conventionally, and the brightness (corresponding to the LED current IL) is controlled within a relatively wide operating current range (for example, from a small current 20 mA to a large current 200 mA). Therefore, the image brightness information Sbr needs to be programmed also within a relatively wide range. However, if running within a relatively wide operating current range, the conventional LED driver 10 is unable to correctly maintain the LED current IL in a preset variation range.
FIG. 2 simulates a variation of the LED current IL in the case where the conventional LED driver 10 runs within a relatively wide operating current range (that is, from a small current 20 mA to a large current 200 mA). As shown in FIG. 2, the curves CV1 and CV2 separately show a result obtained through a Monte Carlo method performed for different numbers of times. In the operating current range from the small current 20 mA to the large current 200 mA, the variation of the LED current IL gradually decreases. Therefore, if the preset variation range is set from −2% to +2%, the variations shown by the curves CV1 and CV2 cannot be maintained in the preset variation range all the time. A conventional solution is to correct the variation of the LED current IL in sections according to the simulation diagram of FIG. 2. As shown in FIG. 2, an operator divides the whole operating current range (that is, from 20 mA to 200 mA) into four sections A, B, C, and D according to the result shown by the actual simulation diagram, and then adjusts the variation in each section of A to D, such that the adjusted variation is maintained in the preset variation range. However, the conventional solution increases the test time and cost, and the operator cannot correctly decide an adjustment amount for each section, causing an unsatisfactory effect after the adjustment.

LED driver with brightness control and driving method thereof


An improved catheterization system includes (i) an occluding wire; (ii) a catheter, and (iii) a fluid supply port in fluid communication with the catheter. The occluding wire includes (i) an elongate wire body; (ii) an occluding tip coupled to a distal end of the elongate wire body; and (iii) a hub coupled to a proximal end of the elongate wire body. The hub of the occluding wire is configured to be coupled to the catheter. The hub of the occluding wire thus prevents the occluding tip from moving in a longitudinal direction with respect to the catheter once the occluding tip has been placed in a desired position with respect to the catheter.

1. The Field of the Invention
This invention is in the field of catheters, including catheterization systems employing occluding wires for use in perfusion catheters.
2. The Relevant Technology
Perfusion catheters have become popular in recent years for use in anesthetizing tissues at an insertion site of a catheter and for treating clotted blood vessels, among other uses. Perfusion catheters typically feature a cannula having infusion holes in a wall thereof for enabling fluid to flow through the wall onto the sensitive tissues of a patient or adjacent an area in which the practitioner has discovered a clot. By positioning the holes of the catheter adjacent the area to be treated, a fluid may be applied to the area, thereby diffusing the clot or anesthetizing the tissues. Once the catheter is positioned at the site of the clot, for example, a thrombolytic fluid capable of dissolving the clot, such as urokinase or streptokinase, is delivered to the site of the clot.
Typical perfusion catheter assemblies comprise a catheter, a fluid supply port, and a hemostasis valve coupled to a proximal end of the catheter which substantially prevents fluid from flowing out a proximal end of the catheter assembly during use. Generally, the distal insertion end of the catheter assembly is open and must therefore be occluded prior to irrigating a liquid from a fluid source through the fluid supply port and into an infusion length of the catheter, where the infusion holes are located. Occlusion of the distal opening of the catheter assembly may be accomplished by inserting an occluding wire through the valve of the assembly and then inserting the wire further along the length of the catheter.
The occluding wire substantially seals the distal end of the infusion catheter during use in order to facilitate spray distribution through the holes. The occluding wire typically includes a wire body portion and a distal sealing ball portion. The sealing ball portion forms a substantially liquid-tight seal at the distal end of the catheter, thereby forcing liquid located proximal to the seal out of the infusion holes of the catheter. Because the inner diameter of the catheter is typically larger than the diameter of the wire body portion of the occluding wire, there is ample space within the infusion catheter for the passage of a liquid out of the infusion holes.
In certain catheters, such as typical 5 French catheters, the inner diameter of the catheter is reduced to a narrow neck at the distal end of the catheter. The sealing ball portion of the occluding wire seats against the inner, narrow neck wall portion of the catheter when inserted into the distal end and thereby substantially occludes the distal opening of the catheter. Consequently, substantially any liquid forced through the catheter is caused to exit through the infusion holes rather than through the opening.
In other catheters, such as typical 4 French catheters, the inner diameter of the catheter is constant throughout the catheter, but the diameter of the occluding ball is configured to substantially match the inner diameter of the catheter. Thus, the practitioner slides the occluding ball to the distal tip, thereby substantially occluding the passageway of the catheter and forcing fluid to flow out of the side perfusion holes proximal to the occluding ball.
When the distal end of the occluding wire is positioned in the catheter, the proximal end of the occluding wire is generally positioned within the hemostasis valve of the catheter assembly. The valve temporarily prevents the occluding wire from moving until the occluding wire is grasped, pushed, or otherwise moved by a practitioner. Consequently, it is generally possible to intentionally or accidentally slide the occluding wire with respect to the catheter, particularly when an adjustable valve is loosened.
Thus, one ramification of present occluding wire and catheter designs is that during use of the catheter system, the proximal end of the occluding wire is generally slidably movable with respect to the hemostasis valve. In addition, the proximal end of the occluding wire generally extends from the proximal end of the catheter assembly and remains exposed to the environment. This dynamic results in a variety of different complications.
For example, the occluding wire can be inadvertently inserted too far distally through the catheter or retracted proximally from a desired position in the catheter. Such inadvertent insertion of the occluding wire may occur when a practitioner accidentally contacts the proximal end of the wire or may be caused by an infusion of fluid under a significant amount of pressure. Such inadvertent actions can cause the occluding wire to lose its occluding effect, for example, by causing the occluding ball to exit the distal opening of the catheter or by inadvertently retracting the ball proximally to a distal set of holes, thereby occluding the fluid supply to the distal set of holes.
In addition to the aforementioned drawbacks associated with typical catheterization systems employing occluding wires, other elongate bodies, such as catheters and guidewires can also be inadvertently displaced from or moved within hemostasis valves.
There is therefore a need in the art for an improved catheterization system for percutaneous catheterization of a blood vessel. More specifically, there is a need in the art for a catheterization system having an improved occluding wire.

Infusion system with fixed occluding wire


A vacuum cleaner head for simultaneously use on submerged non-parallel surfaces, such as the bottom and side of a swimming pool. The cleaning head is divided into multiple parts, connected so that certain parts may rotate up to an angle of almost ninety degrees from the bottom.

A typical swimming pool vacuum cleaner head cleans debris from the bottom and/or sides of a pool but not both, simultaneously.
Other vacuum cleaner heads have been described in, for example, U.S. Pat. Nos. 4,376,320; 4,402,101; 4,502,172; 4,776,058; and 5,048,149. All these devices suffer from the same defect in that they are unable to dean debris simultaneously from the bottom and sides of a pool.

Vacuum cleaner for submerged non-parallel surfaces


A method comprises revolving liquid UF.sub.6 in a swinging bucket rotor or a fixed angle rotor of an ultra centrifuge with a peripheral velocity of 300 m/s or above and at a speed of 40,000 to 65,000 rpm or above, providing force from 240,660 g to 485,000 g or above. The method yields a separation of the U.sup.235 F.sub.6 and U.sup.238 F.sub.6 isotopes.

1. Field of the Invention
This invention relates to the field of isotope separation. More particularly the invention concerns the separation of U.sup.235 from U.sup.238 by centrifugation.
2. Brief Description of the Prior Art
Uranium isotopes have been separated using the following types of centrifuge:
1. Concurrent Centrifuge PA1 2. Counter-current Centrifuge PA1 3. Evaporative Centrifuge
The Concurrent Centrifuge is an application to gaseous flow of the continuous cream separator. As originally conceived, a single stream of gas (this will be vapor of UF.sub.6 if separating U.sup.235 from U.sup.238) enters one end of a rotor through a hollow shaft and two streams are taken off the other end, one from the periphery and one near the axis.
The Counter Current Centrifuge is made tall and narrow, circulation being established by continuous vaporization of liquid UF.sub.6 from the bottom cap of the rotor with condensation in the top cap of the rotor. The condensed liquid is forced out to the periphery and flows down the walls, counter current to the vapor flow. As the liquid passes down the centrifuge, there is a concentration of the heavy isotope in the liquid phase.
In the Evaporative Centrifuge, a small amount of liquid UF.sub.6 is introduced into the centrifuge forming a layer at the periphery. During the spinning of the rotor, vapor is removed slowly through a shaft along the axis. Since the vapor comes from the inside surface of the liquid, it is enriched in the lighter isotope U.sup.235 F.sub.6.
In all the prior art methods, many stages are required to obtain appreciable separation of the isotopes.
In contrast to the prior art methods, the process of the invention produces isotopic separation throughout a liquid phase to obtain complete separation of U.sup.235 F.sub.6 in a single stage with a purity of 100%.

Centrifuge process to separate the isotopes of uranium hexafluoride

258/3 Bahadurabad Housing Society Road-14


A semiconductor device comprising a substrate, a first metal wiring layer made of aluminum alloy and formed on the substrate, a conductive film made of doped polysilicon and formed on a selected part of the first metal wiring layer, an inter-layer insulation film made of plasma SiO.sub.2 and formed on the conductive film and the first metal wiring layer, a contact hole formed in the inter-layer insulation film and being larger than the conductive film, and a second metal wiring layer made of aluminum alloy, extending through the contact hole, and connected to the conductive film.

1. Field of the Invention
The present invention relates to a semiconductor device and a method of manufacturing the device, and more particularly to a semiconductor device having an upper wiring layer and a lower wiring layer and a method of forming these wiring layers.
2. Description of the Related Art
A semiconductor device is known which has an upper wiring layer and a lower wiring layer. These wiring layers are connected, forming a VIA contact, by a specific method. This method will be explained with reference to FIGS. 1A to 1C.
First, as is shown in FIG. 1A, a first inter-layer insulation film 2 is deposited on a semiconductor substrate 1 in which various elements have been formed. Next, a first wiring layer 3 (e.g., an Al-alloy layer) is formed on the first inter-layer insulation film 2. A second inter-layer insulation film 4 (e.g., a plasma SiO.sub.2 film) is deposited on the first wiring layer 3. A photoresist 5 is formed on the second inter-layer insulation film 4. The photoresist 5 has an opening formed in a predetermined portion. Then, as is shown in FIG. 1B, anisotropic etching (e.g., reactive ion etching) is performed on the second inter-layer insulation film 4, using the photoresist 5 as mask. As a result, a contact hole 6 is made in the film 4, thus exposing the first wiring layer 3. Further, as is shown in FIG. 1C, the photoresist 5 is removed, and a metal layer (e.g., an Al-alloy layer) is deposited on the surface of the resultant structure, by means of sputtering. The metal layer is patterned, by the known method, into a second wiring layer 7.
The method described above is disadvantageous in two respects. First, as carbon (C) and fluorine (F) are emitted from the photoresist 5 into the plasma during the anisotropic etching, the metals and impurities (C, Cl, F) contained in the fist wiring layer 3 are sputtered onto the periphery of the contact hole 6 made in the insulation film 4, thus forming a metal-containing organic film 8. Secondly, after the hole 6 is made, thus exposing the first wiring layer 3 to the atmosphere, the layer 3 and the chlorine (Cl) on the surface thereof react, thus forming aluminum chloride (AlCl.sub.4), and then aluminum chloride and the water in the atmosphere react, thus forming chlorine ions, as can be understood from the following formulae: EQU Al+4Cl.sup.- .fwdarw.AlCl.sub.4.sup.- +3e (1) EQU 2AlCl.sub.4 +6H.sub.2 O.fwdarw.2Al(OH).sub.3 +6H.sup.+ +8Cl.sup.-( 2)
The more chlorine ions are formed, the more the first wiring layer 3 is corroded. Ultimately, a thick aluminum hydroxide film 9 is formed on the bottom of the contact hole 6, namely on the exposed portion of the first wiring layer 3.
The presence of the metal-containing organic film 8 and the aluminum hydroxide film 9 result in two undesirable phenomena. First, the second wiring layer 7 has overhangs, with the result that some of the wires, but not all, are cut. Second, the electrical connection between the first and second wiring layers 3 and 7 is inevitably impaired.
The conventional semiconductor, whose upper and lower wiring layers are formed by the method explained above, cannot have a sufficiently high integration density. This is because a relatively broad margin must be provided for the alignment between the masks for forming the upper wiring layer 7 and the contact hole 6.

Semiconductor device having multi-layered wiring, and method of manufacturing the same


A system for delivering energy into a body tissue. A tissue puncturing device is adapted to puncture a tissue surface and generate micro-channels from the tissue surface into the body tissue. A stimulator is adapted to deliver energy to the body tissue over or adjacent to the micro-channels.

The following prior art publications are considered to be relevant for an understanding of the prior art:
U.S. Pat. No. 7,524,317 to Gruzdev et al.
U.S. Pat. No. 8,788,045B2 to Gross
U.S. Pat. No. 6,735,474 to Loeb
U.S. Pat. No. 8,406,886 to Gaunt et al.
U.S. Pat. No. 8,577,458 to Libbus et al.
U.S. Pat. No. 6,148,232 to Avrahami
Transcutaneous electrical nerve stimulation (TENS) is a non-invasive treatment which involves the placement of surface electrodes on the surface of the skin, and the use of an electric current to stimulate nerves for therapeutic purposes. Various medical devices are known that provide transcutaneous electrical stimulation using surface electrodes, for use in many kinds of treatments, such us pain relief, pain treatment, disease treatment, chronic disease treatment and rehabilitation. Penetration of an electric current through a tissue barrier, such as the skin, is limited by the resistance or impedance of the tissue, so that a tolerable electric current will typically only reach superficial nerves. Increasing the current in order to stimulate deeper nerves can result in pain, burning and irritation.
Medical devices are also known that perform percutaneous electrical nerve stimulation (PENS), which is a minimal invasive treatment, in which an ultra-fine acupuncture needle is introduced into a tissue and which penetrates into soft tissues or muscles to electrically stimulate nerve fibers. The acupuncture needle has to be inserted at the precise treatment location and sometimes causes pain and bleeding.
Other medical devices are known that puncture the stratum corneum layer of the skin in order to increase the permeability of the skin to therapeutic compounds. These devices utilize such energy sources as RF currents, ultrasonic waves, laser beams and resistive heating energy technology. These are mainly used for esthetic treatments and also as first stage for allowing transdermal delivery of large molecules such as pharmaceuticals. Such a device is disclosed, for example, in U.S. Pat. No. 7,524,317 to Gruzdev et al.
U.S. Pat. No. 8,788,045B2 to Gross describes a device which includes electrodes that are placed within 1 mm of the tibial nerve of a subject and are driven to treat polyneuropathy by driving a current into the tibial nerve. Polyneuropathy is damage or disease affecting peripheral nerves (peripheral neuropathy) in roughly the same areas on both sides of the body, featuring weakness, numbness, pins-and-needles, and burning pain.
U.S. Pat. No. 6,735,474 to Loeb describes a system for treatment of incontinence and/or pelvic pain that includes injection or laparoscopic implantation of one or more battery or radio frequency-powered micro-stimulators beneath the skin of the perineum and/or adjacent the tibial nerve. The system and method tends to reduce the incidence of unintentional episodes of bladder emptying by stimulating nerve pathways that diminish involuntary bladder contractions. The incidence of fecal incontinence is similarly reduced or eliminated.
Also known is a system for treatment of chronic pain by delivering high-frequency stimulation to sensory nerves in the peripheral nervous system to block chronic pain. An electrode is placed around a peripheral nerve and powered by a pacemaker-size generator.
A minimally-invasive system is also known that delivers percutaneous tibial nerve stimulation for treatment of overactive bladder (OAB) and the associated symptoms of urinary urgency, urinary frequency, and urge incontinence. The system is used in percutaneous stimulation to deliver to the tibial nerve electrical pulses that travel to the sacral nerve plexus, a control center for bladder function.
A system for the treatment of chronic pain of peripheral nerve origin has been disclosed in which electrical signals are transmitted transdermally through an electrode, down a lead to a target nerve. While this device might target electrical stimulation to the targeted nerve, the passage of the stimulation energy is reduced dramatically by the stratum-corneum.
U.S. Pat. No. 8,406,886 describes an implant, system and method for treating a disorder of the nervous system in a subject. The method involves using passive electrical conductors which route electrical current to electrically stimulate a target body tissue to either activate or block neural impulses depending upon the frequency and the disorder to be treated. Electrically-excitable bodily tissues such as nerves and muscles may be activated by an electrical energy applied between electrodes applied externally to the skin. Electrical energy, e.g. current, flows through the skin between a cathode electrode and an anode electrode, eliciting action potentials in the nerves and muscles underlying the electrodes. This method has been used for many years in different types of stimulators, including transcutaneous electrical nerve stimulators (TENS) which relieve pain, therapeutic electrical stimulators which activate muscles for exercise purposes, functional electrical stimulators which activate muscles for tasks of daily life and stimulators that promote regeneration of damaged bones.
U.S. Pat. No. 8,577,458 describes an implantable device for providing electrical stimulation of cervical vagus nerves for treatment of chronic cardiac dysfunction with leadless heart rate monitoring. A stimulation therapy lead includes helical electrodes configured to conform to an outer diameter of a cervical vagus nerve sheath, and a set of connector pins electrically connected to the helical electrodes. A neuro-stimulator includes an electrical receptacle into which the connector pins are securely and electrically coupled. The neuro-stimulator also includes a pulse generator configured to therapeutically stimulate the vagus nerve through the helical electrodes in alternating cycles of stimuli application and stimuli inhibition that are tuned to both efferently activate the heart's intrinsic nervous system and afferently activate the patient's central reflexes by triggering bi-directional action potentials.
U.S. Pat. No. 6,148,232 to Avrahami describes a device for ablating the stratum corneum epidermidis.

Device and methods for delivery of stimulation to a body tissue


An environmentally safe, pesticidally effective composition is provided to control insect/mite pests. In an exemplary embodiment, a composition is provided that includes a pesticidally effective, yet environmentally safe, concentration of at least one spinosyn with at least one additional contact-acting insecticide and/or miticide and at least one solvent or carrier.

Insect and mite pests cause significant losses to plants and plant products, as well as attack and annoy humans and animals, and affect human and animal health by transmitting disease. It is a major goal for those involved in plant care to control insect and mite pests in ways that protect the environment while, at the same time, are effective in combating a wide spectrum of pests. While several environmentally friendly active compounds have been identified and developed for use in the home and garden markets as well as in commercial agriculture, many of these substances have a narrow range of pest control, and thus require the application of multiple compositions to provide adequate pest control.
Accordingly, there remains a need for an improved composition to treat and prevent insect and mite pests and to protect plants and plant products from damage caused by insect and mite pests.

Wide spectrum insecticide and miticide composition


A waterproof keyboard includes a lower housing, a circuit membrane disposed on the lower housing, a pressure plate disposed on the circuit membrane, an elastomer member, an upper housing disposed on the elastomer member and a plurality of key caps disposed on the upper housing. The pressure plate has a main body formed with a plurality of openings and ridges. The elastomer member has a plurality of switch domes disposed in the openings correspondingly, a base layer disposed on the main body, and a plurality of raised portions disposed on the ridges respectively. The ridges of the pressure plate presses tightly to the underside of the raised portions. The pressure plate is constructed to evenly support the elastomer member.

1. Field of the Invention
The present invention is related to a waterproof keyboard. In particular, to a keyboard having switch domes, which have waterproof structures to prevent liquid from intruding the electrical equipment, to avoid damaging the interior components of the electrical devices.
2. Description of Related Art
Waterproof keyboards are designed to provide liquid-resist structure to seal gaps and spaces, so that the liquid does not enter the keyboard to prevent shorting the internal circuit, damaging the keyboard, and/or disabling the computer. A conventional waterproof keyboard is described in U.S. Pat. No. 5,810,491, titled "Splash Water Protected Keyboard". The disclosed keyboard utilized reinforcement ribs protruding downwardly from an upper housing against a rubber mat. Under the rubber mat, a switch foil and a bottom plate are arranged sequentially.
However, the water-resist effectiveness of the above conventional waterproof keyboard still can be improved. The use of reinforcement ribs alone in pressing against the rubber mat to block the liquid has limited effectiveness. Besides, the key mounts, which are used to guide the keys when pressed or depressed by the user, are arranged above the switch domes. When any liquid is accidentally splashed on the keyboard, the liquid can enter the keyboard via these key mounts and flow unrestrictedly along the rubber mat. Moreover, the keyboard lacks sufficient retaining structures around the switch domes. This deficiency adversely affects the touch feel of the user when depressing the keys.
Therefore, it is desirable to propose a novel waterproof keyboard to overcome the above-mentioned problems. The proposed waterproof keyboard not only has good waterproof capability, but also provides good touch feel when stroking the keys.


A method is provided, the method comprising collecting related signals capable of having unrelated names into a Krutibus, defining a bus capable of connecting the related signals in a bus definition file in the Krutibus and providing at least one of component declarations of the bus and different uses of the bus in a hardware description language (HDL) circuit description using the bus definition file in the Krutibus. The method also comprises providing a Krutibus preprocessor to read the hardware description language (HDL) circuit description for the at least one of the component declarations of the bus and the different uses of the bus and to generate a hardware description language (HDL) circuit description naming the bus components.

1. Field of the Invention
This invention relates generally to computer software and, more particularly, to a method for describing computer hardware.
2. Description of the Related Art
Hardware description languages (HDLs) typically have "primitives" describing "wires" and "modules." Verilog is an example of a conventional hardware description language (HDL). However, modern computer hardware design is typically done using "busses" and not "wires." Verilog and other conventional Hardware description languages (HDLs) are typically poorly suited to modern computer hardware design done using "busses" and not "wires."
Conventional schematic-based hardware descriptions typically have a poor, but still useful, idea of a "bus." The typical bus as described in a conventional schematic consists of a bunch of signals with a single name and differing bit numbers. Some conventional schematics packages let a bunch of different-named signals be combined, and later separated, by special combining and separating symbols. The user is typically responsible for making sure that the right data is put together and split apart. This manual process of making sure that the right data is put together and split apart is error-prone and is typically awkward enough that it is almost never used.
Conventional hardware description language (HDL) descriptions of hardware are largely replacing schematic-based hardware descriptions. However, the hardware description language (HDL) descriptions of hardware are typically as limited as the most limited schematics-based schematics capture hardware descriptions. The hardware description language (HDL) descriptions of hardware similarly only allow busses to be made up of like-named signals with different bit numbers. Modem computer hardware design is very constrained by these shortcomings in hardware description language (HDL) descriptions of hardware.
The present invention is directed to overcoming, or at least reducing the effects of, one or more of the problems set forth above.

Coding speed and correctness of hardware description language (HDL) descriptions of hardware


A semiconductor device comprising a lead frame, a semiconductor chip on the lead frame, a wiring provided between the lead frame and the semiconductor chip, a silicon nitride film formed on the semiconductor chip, the wire, and the lead frame, and a mold formed from a plastic material to enclose the silicon nitride film therein and having a vent hole formed on the undersurface of the lead frame, so that the lead frame is partly exposed to the outside.

1. Field of the Invention
The present invention relates to sealing for a semiconductor device.
2. Description of the Prior Art
Conventionally, the final coating of a semiconductor chip (a transistor or a semiconductor device on which transistors are integrated in a plurality of locations, hereinafter referred to as a chip) is carried out at the wafer level. Therefore, an aluminum pad section (usually 100 .mu.m.times.100 .mu.m) which is formed subsequently for wire bonding is exposed to the epoxy mold section.
For this reason, in a plastic Dual Inline Package (DIP) comprising a lead frame 37 having a die pad 28 and a stem 35, a chip 26 adhering closely to the die pad 28 and having an aluminum pad 38 for electric connection as shown in FIG. 1, it has been ascertained that silicon nitride 30 has a blocking effect against the influx 33 of moisture (humidity) through a plastic bulk 36, but it is completely ineffective against the influx 34 of moisture along a wire or against the influx 31 of moisture through a crack 32 at the interface of the lead frame 37 and the mold 36. For this reason, the aluminum pad 38 is easily corroded, so that the characteristics of the semiconductor device deteriorate, leading to reduced reliability.
Especially, for example, in the case where the 410B epoxy mold material of the Morton Co. is used for the mold section, large quantities of chlorine remain generally throughout the mold material, and chlorine ions are formed by virtue of the existence of water to react with the aluminum, so that corrosion occurs. Consequently, the aluminum becomes aluminum hydroxide, and wire breaks occur. Therefore, the reliability of the semiconductor device outstandingly deteriorates.
In addition, semiconductor device is completely defenseless against the occurrence of corrosion at the pad section due to the moisture which enters the crack 32 which is easily developed at the bonding surface of the lead frame and the epoxy mold when the frame is bent at the lead section and the tie bar is cut.
Further, when an IC chip molded with these plastics is soldered to a substrate, there is the problem that when heated to about 260.degree. C., the moisture remaining in the inner part of the plastic package turns into steam, expands in the inside of the plastic package, and cracks appear in the plastic package. In the prior art technology known to eliminate this problem, the steam is allowed to escape to the outside of the plastic package through a vent hole provided in the underside of the die pad of the lead frame, whereby the development of cracks is therefore suppressed.
However, when this type of configuration is adopted, the problem arises that when the vent holes are provided, the underside of the die pad of the lead frame is directly exposed to the outside atmosphere, so that corrosion occurs on the underside of the die pad.
Specifically, moisture from the outside atmosphere enters and concentrates in an interface between the mold and the lead frame, and reliability of the semiconductor device is decreased. In other words, cracks are produced in in the mold due to thermal expansion, resulting in corrosion, thereby deteriorating the intimate contact between the mold and the lead frame.

Semiconductor device having a film-covered packaged component

Semiconductor Energy Laboratory Co., Ltd.


A multi-reactive silicon compound has at least one polyalkyleneglycol substituent with the number average molecular weight being 200 to 10,000 as synthesized by reacting an organohalosilane compound having Hxe2x80x94Si bonds with a polyalkyleneglycol ether compound having unsaturated substituents in the presence of a hydrosilylation catalyst. The multi-reactive silicon compound having polyalkyleneglycol substituents is very soluble in organic solvents and reactive to living polymeric ions with high thermal stability due to multiple functional groups, and active living groups. Thus, the addition of the multi-reactive silicon compound to a living polymer solution during an anionic or cationic polymerization reaction activates an intense substitution reaction under mild conditions to introduce a third functional group to the end or side chain of the polymer comprising a repeating monomer unit and provide organic-inorganic hybrid polymers.

The present invention relates to a multi-reactive polyalkyleneglycol ether having polyalkyleneglycol substituents and a synthetic method thereof, and more particularly, to a coupling agent having not only multiple halogen substituents to provide high reactivity with living polymeric anions but also polyalkyleneglycol substituents to enhance compatibility with inorganic fillers, and a synthetic method thereof.
Elastomers are easily synthesized and have interesting mechanical properties, including elasticity, and broadly used in various applications such as tires, automobile parts, shock absorbents, shoes and packing. Such elastomers have been developed for organic-inorganic hybrid materials, which are synthesized by mixing silica or glass fibers in vulcanization in order to improve thermal stabilities and mechanical strength.
However, organic polymers are generally incompatible with inorganic fillers in the preparation of such organic-inorganic hybrid materials. To solve this problem, coupling agents have been introduced, or the organic polymers are chemically modified to improve the compatibility with inorganic materials. For the second solution, as well known in the related art, the living polymer is reacted with anion reactive terminators to produce a polymer having inorganophile substituents.
Miura et al., for example, reported a method for preparing a polymer modified with 4-formylphenylalkoxyamine in the anionic polymerization of butadiene (Macromolecules, 1999, 32(25), 8356).
Bronstert et al. disclosed a method for preparing a polymer modified with hydroxyethylamino or hydroxyethylpolyoxyethyleneamino compound (Germany Ger. Offen., 5 pp.).
However, the compounds used in the above documents have still problems of insufficient compatibility with inorganic particles such as silica. In an attempt to solve this problem, many studies have been reported on an organic-inorganic hybrid polymer using silicon compounds. For example, Korean Patent No. 95-704405 discloses a method for bonding hexamethylchlorosiloxane to the end of a living polymer. While the problem related to the phase separation between inorganic fillers and organic polymer is somewhat solved in this method, it is difficult to increase the molecular weight of the polymer and enhance the mechanical properties of the polymer. In order to increase the molecular weight of the polymer and thus improve the mechanical properties of end modified polymers, multi-functional silicon containing terminators are demanded.
On the other hand, silicon containing compounds having halogen as terminal or branched substituents are used as additives in coating, coupling agent, adhesive and silant in order to enhance mechanical properties of the coating surface or the substrate as well as to improve thermal stability and compatibility.
For example, U.S. Pat. No. 5,858,468 discloses a composition comprising a mixture of (a) a polysiloxane having unsaturated groups and (b) a polysiloxane containing reactive Sixe2x80x94H groups. This composition is useful for preparing a coating composition curable at ambient temperature.
U.S. Pat. No. 5,373,079 discloses a polydimethylsiloxane having alkoxy, acyloxy, N-methylbenzamido or alkyl groups. Also, U.S. Pat. No. 5,340,899 discloses a sealant composition comprising a mixture of (a) a polysiloxane having hydroxy end groups and (b) a polysiloxane having vinyl or methylacetamido end groups. This composition is useful for reducing the modulus of the siloxane sealant.
U.S. Pat. No. 5,194,553 discloses a method for preparing an organofunctional-terminated polydiorganosiloxane polymer and a copolymer thereof, which method is useful for making a polydimethyl siloxane having 5-hexenyl end groups. This patent also discloses a method for preparing an organofunctional-terminated polydiorganosiloxane polymer using an organofunctional chlorosilane end-blocker, and a method for preparing an organofunctional-terminated polydiorganosiloxane copolymer using an organofunctional chlorosilane end-blocker and an organofunctional chlorosilane.
These reactive silicon compounds are capable of reacting with at least two living polymers to produce multi-substituted elastomer when they have the functional groups with at least two substituents. However, the polydimethylsiloxane is ready to be decomposed prior to reaction with the living polymer due to its low storage stability and very poor in reactivity with living polymeric anions, which makes it difficult to activate multi-substitution reactions.
Thus there is a need of providing a silicon compound having high storage stability and excellent reactivity.
U.S. Pat. No. 6,005,036 discloses a method for preparing a polysilane compound used as a process stabilizer. Also, the halogen-substituted silicon compounds are widely used in various applications such as adhesion additives (U.S. Pat. No. 6,060,559); water-absorbent agents (U.S. Pat. No. 5,981,070); and coatings. Thus there is a need of providing such a silicon compound containing functional groups such as halogen as well as polar functional groups.
In an attempt to solve the problems, the inventors of this invention have studied on a synthesis of silicon containing terminators, particularly, silicon compound having polar substituents with excellent compatibility with inorganic fillers, and contrived halosilyl polyalkyleneglycol ether macromers having at least one polyalkyleneglycol substituent.
It is, therefore, an object of the present invention to provide halosilyl polyalkyleneglycol ether macromers having polar functional groups and at least two halogen substituents that can participate in various substitution reactions, more specifically, halosilyl polyalkyleneglycol ether macromers reactive to at least one equivalent of polymers in an anionic or cationic polymerization reaction.
To achieve the above object of the present invention, there is provided a reactive halosilyl polyalkyleneglycol ether containing at least two functional groups with at least one polyalkyleneglycol substituent and at least two halogen substituents, the reactive halosilyl polyalkyleneglycol ether having a number average molecular weight of 200 to 10,000 and being represented by the formula 1, (X)a(R)b(R1)cSixe2x80x94C(R4)(R5)xe2x80x94Si(X)d(R)e(R2)f, in which X is a halogen atom selected from the group consisting ofF, Cl, Br and I; R1 and R2 are the same or different and independently represent hydrogen, an alkyl group containing 1 to 10 carbon atoms or a C1 to C10 alkyl group having F or Cl substituents; R4 and R5 are the same or different and independently represent hydrogen, Si(X)a(R)b(R1)c or Si(X)d(R)e(R2)f; R is a polyalkyleneglycol group represented by the formula {C(R6)(R7)CH(R8)C(R6)(R7)Z}xe2x80x94{C(R6)(R7)C(R6)(R7)O}gR9; R6, R7 and R8 are the same or different and independently represent hydrogen, an alkyl group containing 1 to 10 carbon atoms, or a C1 to C10 alkyl group having F or Cl substituents; R9 is methyl or ethyl; Z is oxygen or p-substituted benzene ring (C6H4); a and d are the same or different and independently represent a number from 1 to 3; b and e are the same or different and independently represent a number from 0 to 2; c and fare the same or different and independently represent a number 0 or 1, wherein a+b+c+d+e+f=6; and g is a number from 1 to 20.
The reactive halosilyl polyalkyleneglycol ether represented by the formula 1 is synthesized by reacting a halogen-substituted silane compound having a Sixe2x80x94H bond as represented by the formula 2, (X)a(H)b(R1)cSixe2x80x94C(R4)(R5)xe2x80x94Si(X)d(H)e(R2)f with a polyalkyleneglycol ether having a double bond as represented by the formula 3, {C(R6)(R7)xe2x95x90C(R8)C(R6)(R7)Z}xe2x80x94{C(R6)(R7)C(R6)(R7)O}gR9, in which X, Z, R1 to R9 and a to g are as defined above formula 1, in the presence of a hydrosilylation catalyst.
Hereinafter, preferred embodiments of the present invention will be described in detail as follows.
The reactive halosilyl polyalkyleneglycol ether represented by the formula 1 is prepared by reacting a silane compound having at least one halogen substituent as represented by the formula 2 with a polyalkyleneglycol derivative having unsaturated groups as represented by the formula 3 in the presence of a hydrosilylation catalyst.
Specific examples of the compound represented by the formula 2 include Cl2HSiCH2SiHCl2, Cl3SiCH2SiHCl2, 1,1,3,3-tetrachloro-2-(dichlorosilyl)-1,3-disilabutane, Cl2MeSiCH2SiHCl2 and Cl2HSiCH2SiClMe2, the syntheses of which compounds are disclosed in the reference documents (J. Organomet. Chem., 516, 91 (1996); U.S. Pat. Nos. 5,233,069 and 5,399,740; and Organometallics, 12, 2360 (1993)).
Specific examples of the compound represented by the formula 3 incluae CH2xe2x95x90CHCH2O(CH2CH2O)gCH3, CH2xe2x95x90CHCH2O(CH(CH3)CH2O)gCH3, CH2xe2x95x90CHCH2O(CH2CH2O)gCH2CH3, CH2CHCH2O(CH(CH3)CH2O)gCH2CH3 and CH2xe2x95x90CHxe2x80x94Bzxe2x80x94CH2CH2O(CH2CH2O)gCH3.
These compounds are synthesized by an industrial method disclosed in the reference document, for example, Makromol, Chem., 182, 1379 (1981), or commercially available from manufacturing companies such as Aldrich.
The compound of the formula 2 has at least one functional group participating in the reaction, and is preferably used at the equivalent ratio with respect to the compound of the formula 3 being 1:1 to 5:1.
Examples of the silylation catalyst include chloroplatinic acid, transition metals, e.g., palladium, rhodium or platinum, and complex compounds, which are all commercially available from manufacturing companies such as Aldrich or synthesized by known methods. Examples of the reaction solvent as used herein may include, if not specifically limited to, organic solvents such as benzene, toluene or xylene.
The silylation temperature is in the range from xe2x88x9220xc2x0 C. to 150xc2x0 C., preferably, from room temperature to 120xc2x0 C. The silylation is conducted in the nitrogen atmosphere with stirring. The silylation time is not specifically limited and may be preferably in the range from about 30 minutes to one week.
After the completion of the reaction and removal of the solvent under vacuum, the resulting material is purified to produce the halosilyl polyalkyleneglycol ether represented by the formula 1.
The halosilyl polyalkyleneglycol ether of the formula 1 according to the present invention has halogen groups highly reactive to the compounds containing living anionic or cationic groups, hydroxyl groups or amine groups, and thus can participate in various reactions.
For example, the halosilyl polyalkyleneglycol ether of the formula 1 is highly reactive to living anionic or cationic polymers to form a covalent bond between the polymers and silicon compounds, and can be used in the preparation of a polymer modified with silicon compounds containing polyalkyleneglycol. Also, the polyalkyleneglycol group enhances compatibility with inorganic fillers, e.g., silica, carbon black, metal oxides, metal powder, glass fiber or other ceramics, as well as mechanical properties, and can be used for organic-inorganic hybrid composite materials.
In particular, the halosilyl polyalkyleneglycol ether of the present invention is very soluble in normal organic solvents such as benzene, toluene, xylene, acetonitrile, sulfolane, propylene carbonate and acetone, and highly reactive to living polymeric ions or radicals generated by anionic, cationic or radical initiators. The polymeric ions or radicals may include reaction products comprising monomers such as aromatic or aliphatic diene with unsaturated groups, or polysiloxane or cyclosiloxane.
For example, the tetrachlorosilicon compound having triethyleneglycol substituents prepared according to the present invention is reacted with polystyrene-butadiene living polymeric ions generated from an anionic polymerization reaction to produce a modified polystyrene-butadiene-silane polymer having at least three polystyrene-butadiene polymeric substituents and two triethyleneglycol substituents.
Therefore, the multi-reactive silicon compound having polyalkyleneglycol groups prepared according to the present invention can be used for preparation of modified polymers, which is usable for compositions of various use purposes, such as conductive rubber, tire, sticking agent, coating solution, sealant, and paint.
Hereinafter, the present invention will be described in detail by way of examples, which are not intended to limit the scope of the present invention.

Multi-reactive silicon compound having polyalkyleneglycol substituents and synthetic method thereof


Interconnects with harmonized stress and methods for fabricating the same. An interconnect comprises a substrate having a conductive member. A composite low-k dielectric layer interposed with at least one stress-harmonizing layer therein overlies the substrate. A conductive feature in the composite low-k dielectric layer passes through the at least one stress-harmonizing layer to electrically connect the conductive member.

The present invention relates to semiconductor features, and in particular to an interconnect for integrated circuits.
Reduction of integrated circuit feature size has resulted in levels of electrically conductive interconnects being placed closer together vertically, as well as reduction of the horizontal spacing between the electrically conductive interconnects, such as metal lines. As a result, capacitance has increased between such conductive portions, resulting in RC (resistance×conductance) delay time and crosstalk effect. One proposed approach to this problem is to replace the conventional silicon oxide (SiO2) dielectric material, having a dielectric constant (k) of about 4.0, with other insulation material having a lower dielectric constant, to thereby lower capacitance.
Unfortunately, low-k dielectric materials have various problems that make integration into existing integrated circuit structures and processes difficult. Compared to conventional dielectric materials used in semiconductor fabrication, most low-k materials typically present characteristics such as high tensile stress. Such high tensile stresses accumulating in a semiconductor structure can lead to bowing or deformation, cracking, peeling, or formation of voids of a film therein, which can damage or destroy an interconnect that includes the film, affecting reliability of a resulting integrated circuit.

Taiwan Semiconductor Manufacturing Co., Ltd.