The invention relates to a process for the preparation of high yields of 5-oxohexane nitriles with minimum formation of 1 undesired isomer. Such nitriles may be utilized as starting materials for the preparation of pharmaceutical and agrochemical intermediates and as well as final products. The process comprises reacting a methyl ketone and an .alpha.,.beta.-unsaturated nitrile in the presence of a catalytically effective amount of a strong base. One of the products which may be created by the process is 2,4-dimethyl-5-oxohexane nitrile.

1. Technical Field
The invention relates to a process for the preparation of high yields of 5-oxohexane nitriles. Such nitriles are formulated by catalytic conversion of a methyl ketone and an .alpha.,.beta.-unsaturated nitrile in the presence of a strong base.
One type of 5-oxohexane nitrile which can be created using the present process is 2,4-dimethyl-5-oxohexane nitrile.
2. Background Information
A related process is known from US patent specification U.S. Pat. No. 2,850,519. In particular, this publication describes the reaction of acrylic acid nitrile and ketones in the presence of primary amines as catalysts. It has appeared, however, that when asymmetrical methyl ketones are used in this process, as starting material in combination with other nitriles than acrylic acid nitrile (e.g. methacrylic acid nitrile), isomer mixtures are formed that contain a substantial amount of undesired isomer, namely the product of addition of the .alpha.,.beta.-unsaturated nitrile to the methyl group of the ketone, whereas this is not the case when acrylic acid nitrile is used as starting material in such a reaction. Furthermore, isolation of the isomers generally is very difficult.
As a consequence, the yield in which the 5-oxohexane nitriles can be obtained in purified form, that is, with less than 0.2 wt. % of undesired fisomer, generally is very low, as a major part of the nitrile is lost in the separation process.

2,4-dimethyl-5-oxohexane and a method of use therefor


An objective of this invention is to provide a process for selecting rationally and quickly a wet process treatment in which an etchant can be shared based on a minimum preliminary investigation while eliminating cross contamination derived from a newly employed material, in a cleaning-apparatus line configuration in a process for manufacturing a silicon semiconductor device. In advance, an element which is suspected to cause cross contamination is added to an etchant used in a wet processing, a silicon substrate is immersed in the etchant, and then a correlation between a concentration of the element adhesively remaining still on the surface of the silicon substrate after the etchant is washed out with water and a concentration of the dissolved element in the etchant. On the basis of the result, the upper concentration limit of the element remaining by cross contamination is estimated when sharing the etchant. Then, with reference to the upper limit, whether deterioration of device properties occurs is evaluated to determine acceptability of etchant sharing.

1. Field of the Invention
This invention relates to a process for designing a cleaning-apparatus line configuration in a manufacturing process for a semiconductor device, and a cleaning apparatus optimized for its line configuration according to the designing process.
2. Description of the Prior Art
In a process for manufacturing a semiconductor device, a variety of pretreatment and cleaning procedures are conducted before some steps such as forming a conductive material film and an insulating film on a semiconductor surface and a conductive material film on a dielectric material film. Such pretreatment/cleaning procedures include removing undesired or remaining materials from a previous step, e.g., an undesired photoresist mask, removing particles or residues inevitably remaining after a step such as dry etching; and exposing a clean surface used in the next step, e.g., removing an undesired oxide film formed on a surface of a semiconductor device or conductive material. Each pretreatment/cleaning has a specific purpose depending on steps before and/or after the procedure, and conducted with an appropriate means. When cleaning by selectively removing a film, particles or residues remaining in a small amount on a surface, a variety of etchants may be sometimes used to slightly etch the whole surface. Alternatively, a particular substance is selectively dissolved under mild conditions. Furthermore, two or more of these means may be combined to conduct a wet process meeting a requirement in each case.
A process for manufacturing a semiconductor device comprises several etching steps, some of which employ wet etching rather than dry etching in the light of suitability. These various wet etching steps themselves selectively dissolve and remove a target material layer or a given area, and at the end of etching, an etchant on a surface is thoroughly cleaned/removed.
In a wet process such as wet etching, cleaning and pretreatment, a whole substrate is immersed in an etchant for chemical treatment. An etchant employed in the wet process is usually used for removing adhering contaminants during another step or dissolving a film itself such as a resist or natural oxide film; i.e., for primarily dissolving and removing a substance of interest. However, a new material such as a special metal has been recently employed in a semiconductor device, so that as a special case, a substance not of interest may be concomitantly dissolved in an extremely small amount. Thus, besides ion species generated mainly after dissolving a substance of interest, there may be present ion species generated by a concomitant dissolution reaction in a very small amount in an etchant. For example, when dissolving and removing an oxide film on the rear face of a silicon substrate as a pretreatment, a very small amount of a conductive material layer formed on the surface of the silicon substrate is dissolved and thus ions derived from a metal element composing the conductive material (hereinafter, referred to as xe2x80x9cderived ionsxe2x80x9d) are generated in the etchant.
During washing an etchant adheringed to a surface with water after a wet process, a small amount of adhering etchant is diluted, so that the level of the above-mentioned various trace ion species is further lowered. As a result, it is quite rare that various molecules or ion species:dissolved in the etchant remain on the surface. The substrate surface, therefore, usually becomes considerably clean after the wet process. In other words, in each process, a process design and conditions are chosen to substantially eliminate element ions or compound molecules inevitably contained in an etchant from the surface by removing the etchant with water after the process.
There will be described a wet process in a manufacturing process for a MOSFET for a logic circuit whose manufacturing process has been already established. For a series of steps for manufacturing an N-MOSFET for a logic circuit, FIG. 6 shows the first half to the step of forming an FET while FIG. 7 shows the latter half from the step of forming an interlayer insulating film. Purposes of wet processes in the manufacturing process and types of dopants used therein will be described with reference to cross sections sequentially shown in FIGS. 6 and 7 according to the process order.
In the step illustrated in FIG. 6(a), on a silicon substrate 601 is formed a buried oxide film for separation between devices. On the substrate surface is formed a trench by a known etching technique. On the substrate surface on which the trench has been formed is deposited an oxide film 600 by a known bias CVD technique. Then, as illustrated in FIG. 6(a), the oxide film 600 is removed by a chemical-mechanical polishing (CMP) technique to expose the surface of the silicon substrate 601. The oxide film buried in the trench becomes a shallow trench isolation (STI) 602 (hereinafter, referred to as a xe2x80x9ctrench isolationxe2x80x9d) for separation between devices. In the above series of steps, the rear face of the wafer is cleaned after CMP for removing, e.g., an oxide film adhering to the rear face.
Subsequently, in the step illustrated in FIG. 6(b), for example, B (boron) as an N-type dopant is ion-implanted with given depth and doping amount according to a designed threshold voltage of an FET to form a doping area 603. After the step, the exposed silicon substrate 601 is covered with a natural oxide film formed during the step. The uneven natural oxide film is removed by dissolving and cleaning with an agent such, as diluted hydrofluoric acid (DHF; diluted HF). The exposed substrate surface is sequentially washed with an ammonium hydroxide-hydrogen peroxide mixture (APM), a hydrochloric acid-hydrogen peroxide mixture (HPM) or a sulfuric acid-hydrogen peroxide mixture (SPM), to remove contaminants adhering to the silicon substrate surface (the first cleaning step). Then, as illustrated in FIG. 6(b), on the clean surface thus obtained is formed a gate insulating film 604 with a given thickness.
Then, in the step illustrated in FIG. 6(b), on the gate insulating film 604 is deposited a polysilicon layer by CVD. Since the polysilicon layer is used as a gate, it is doped with, for example, an N-type dopant such as P (phosphorous) to a concentration of, e.g., about 1020 cmxe2x88x923 for endowing desired conductivity. Then, a resist pattern 630 to be an etching mask is formed by a known photolithography. Using the mask, the polysilicon is selectively etched by reactive dry etching using a reactive gas such as HBr and Cl2, to form a gate electrode shape. As shown in FIG. 6(c), the gate. insulating film 604 remains only under the gate electrode 605 while the insulating film 604 covering the other area is also removed.
The resist 630 is peeled off by SPM cleaning and then APM cleaning. The surface is cleaned with an ammonium hydroxide-hydrogen peroxide mixture (APM) and then HPM or SPM to remove contaminants and residual organic compounds on the polysilicon of the gate electrode 605 and the silicon surface in areas to be a source-drain area 606, 607 (the second cleaning step). Then, for example, P (phosphorous) as an N-type dopant is ion-implanted at a low level, using the gate electrode 605 as an implanting mask to form light-doping areas 606, 607.
Then, in the step illustrated in FIG. 6(d), an insulating film is deposited on the whole surface of the substrate including the polysilicon of the gate electrode 605. The insulating film is etched by dry etching with perpendicular anisotropy, so that only the insulating film deposited on the side wall of the gate electrode 605 can remain to form a side wall 605a. Then, for example, As (arsenic) as an N-type dopant is ion-implanted at a high level using the gate electrode 605 and the side wall 605a covering its wall as an implanting mask to form heavy-doping areas 608, 609. In this step, as shown in FIG. 6(d), there is formed a main part of a MOSFET with a self-aligned LDD structure.
Then, in the step illustrated in FIG. 6(e), on the top of the gate electrode 605, the source area 608 and the drain area 610 is formed the first conductive material layer 610 corresponding to the first interconnect (the lowest interconnect) in the interconnects connected to a transistor. Recently, a variety of metal silicides with good heat resistance have been applied as the first conductive material layer 610. For example, when using titanium silicide, titanium (Ti) is deposited on the whole surface of the polysilicon of the gate electrode 605, the side wall 605a covering its wall and one side of the substrate surface, and the product is heated at 690xc2x0 C. to silicide the area where the silicon surface is directly in contact with titanium. Then, unreacted titanium deposited on, for example, the side wall 605a, the trench separation 602 and the insulating film is selectively etched off. The product is subject to lamp annealing at 840xc2x0 C. to form a silicide layer as the first conductive material layer 610 closely adhering to the top of the gate electrode 605, the source area 608 and the drain area 609.
After the step in FIG. 6(e), a pad oxide film and a silicon oxide film may be formed on the whole surface of the substrate (not shown). In such a case, hydrofluoric-nitric acid(a mixture of hydrofluoric acid and nitric acid: HF+HNO3+H2O) is sprayed only on the rear surface of the substrate to remove a silicon nitride film adhering to the surface for cleaning the rear surface. Alternatively, after depositing a thicker silicon oxide film on the silicon nitride film in the substrate surface, the entire substrate is immersed in hot phosphoric acid to remove the silicon nitride film adhering to the rear surface of the substrate for cleaning the rear surface.
Then, in the latter step illustrated in FIG. 7, an interconnect to be connected with a transistor is formed. First, as shown in FIG. 7(f), on the substrate surface is deposited an insulating film as an interlayer insulating film 611 such as a silicon oxide film.
Then, in the step illustrated in FIG. 7(g), on the interlayer insulating film 611 is formed a resist pattern 612. Contact holes 613a, 613b penetrating the interlayer insulating film 611 is formed in given positions on the first conductive material layer 610 formed on the source area 608 and the drain area 609 by dry etching using the above resist pattern 612 as a mask. As shown in FIG. 7(g), the bottoms of the contact holes 613a, 613b reach the surface of the first conductive material 610. Similarly, in the gate electrode 605 is formed a contact hole reaching the surface of the first conductive material layer 610 formed on the polysilicon layer at a point not shown in this figure.
Before the step illustrated in FIG. 7(h), it is cleaned by SPM and APM cleaning for peeling/removing the resist pattern 612 (the third cleaning step). Subsequently, the surfaces of the first conductive material layer 610 such as a silicide layer exposed in the bottoms of the contact holes 613a, 613b are cleaned with, for example, APM, SPM or HPM, diluted hydrofluoric acid (DHF) or BHF, or FPM.
A conductive material is buried in the contact holes 613a, 613b for connecting the first conductive material layer 610 with an electrode interconnect formed on the interlayer insulating film 611 to form a plug 614. Specifically, on the exposed first conductive material layer 610 such as a silicide layer is selectively deposited, for example, polysilicon doped with phosphorous, an N-type dopant, as a conductive material for filling the contact holes as shown in FIG. (h) to form a plug 614. Similarly, a plug is formed in the contact hole formed on the gate electrode 605. As the above plugs, a layered structure of Ti, TiN and W may be used instead of polysilicon.
In the final step, electrode interconnects formed on the interlayer insulating film 611, i.e., a source and a drain electrode interconnects and a gate electrode interconnect, are formed such that they are connected to the corresponding plugs, respectively. Generally, in a MOSFET for a logic circuit, such a surface electrode interconnect is made of a metal such as aluminum and copper. When high-temperature resistance comparable to the first conductive material layer 610 is required, the surface electrode interconnect may be a metal silicide film such as tungsten silicide deposited by sputtering.
Next, a process for forming a memory cell area will be described with reference to FIG. 8. In a memory circuit such as a DRAM (dynamic random access memory), a capacitative element required in a memory device is formed in addition to a MOSFET. Specifically, the polysilicon gate 605 and the gate electrode interconnect 610g are used as a word line while the source 608 is connected to a bit line 615 formed on the interlayer insulating film 611 via the plug 614 and the source electrode 610s. A drain 609 is connected with a capacitative element 618 via a plug 621 and a drain electrode 610d.
A MOSFET for a memory circuit is formed by the process as in the MOSFET for a logic circuit shown in FIGS. 6 and 7. However, a capacitative element connected to the drain 609 is instead formed in the process illustrated in FIG. 8, while only the contact hole 613b and the plug 614 are not formed on the drain 609 in the steps illustrated in FIGS. 7(g) and 7(h).
After the step illustrated in FIG. 7(h), on the interlayer insulating film 611 is formed a bit line 615 made of a metal silicide such that it is connected with the plug 614 on the source 608, as shown in FIG. 8(i).
In the step illustrated in FIG. 8(i), the interlayer insulating film 611 as well as the first interlayer film 616 covering the word line formed on the insulating film and the bid line 615 are first deposited. As shown in FIG. 8(i), a contact hole is formed, which penetrates the first interlayer film 616 and the interlayer insulating film 611 and reaches the surface of the first conductive material layer 610d formed on the drain 609.
Subsequently, before the step illustrated in FIG. 8(h), the surface of the first conductive material layer 610d (a silicide layer) exposed in the bottom of the contact hole is cleaned with, for example, APM, SPM or HPM, diluted hydrofluoric acid (DHF) or BHF, or FPM. On the exposed first conductive material layer 610d is selectively deposited, for example, polysilicon doped with phosphorous, an N-type dopant, as a conductive material for filling the contact hole 613b to form a contact plug 621.
On the first interlayer film 616 is formed the second interlayer film 617, and then a lower electrode 618, a dielectric film layer 619 and an upper electrode 620 are formed in sequence. The lower electrode 618 in a capacitative cell disposed on the first interlayer film 616 is formed to be tightly connected with the above contact plug 621 and electrically connected with the drain 609. As shown in FIG. 8(h), the upper electrode 620 is formed on the second interlayer film 617 while in the capacitative cell it is in contact with a dielectric film layer 619 such as a BST (BaxSr1-xTiO3), Ta2O5 or Si3N4 surface. Here, after depositing the dielectric film layer 619, its surface is cleaned and then the upper electrode is formed. When using a silicon nitride film as an insulating film of capacitor, a wafer is placed under a nitrogen atmosphere and heat-treated at an high temperature, e.g., about 890xc2x0 C. to nitride the surface of the lower electrode 618 to form a silicon nitride film. When using a tantalum oxide film as a capacitor insulating film, a wafer is annealed at an elevated temperature of 750 to 850xc2x0 C. (high temperature baking) for phase transition in a crystal structure to form the dielectric film layer 619 with a desired dielectric constant.
As described above, when tight contact is required between different materials, pretreatment/cleaning is conducted with a variety of etchants for providing a clean surface before, for example, depositing a conductive material on a silicon substrate surface, depositing polysilicon on a silicide film, depositing a conductive material on a polysilicon surface, or forming a gate insulating film on a silicon substrate surface. Etchants which may be used in a wet process include, an ammonium hydroxide-hydrogen peroxide mixture (APM), a sulfuric acid-hydrogen peroxide mixture (SPM) and diluted hydrofluoric acid (DHF) as described above, as well as an ammonium fluoride buffer-hydrofluoric acid mixture(BHF: buffered HF), 50% hydrofluoric acid(HF), a hydrochloric acid-hydrogen peroxide mixture (HPM), phosphoric acid and hydrofluoric-nitric acid (a hydrofluoric acid-nitric acid mixture).
In commercial production, a plurality of silicon substrates in the same lot are simultaneously subject to a sequential process according to a series of production steps for mass production. Alternatively, a plurality of silicon substrates belonging to different product lots are simultaneously subject to a sequential process. In the process, it is often that while treating the plurality of substrates composing the above group, etchants used in individual wet processes are continuously used without being replaced. Cleaning performance of an etchant used in a wet process treatment is gradually changed, i.e., gradual reduction in cleaning performance so that it is necessary to replace with a new etchant. Until replacement, the plurality of silicon substrates passing through the same steps are sequentially processed. As the total number of treated substrates increases, for example, various element ion species dissolved during the wet process treatment are accumulated. As described above, each wet process is designed and chosen to prevent the above various element ion species dissolved during the wet process treatment from remaining on a surface after washing an etchant even when the various element ion species are accumulated in the etchant.
Various types of etchant have been studied for a wet process, and the same type of etchant is used in some wet processes. If various element ion species dissolved in an etchant are common and do not remain on or contaminate a surface in a plurality of wet processes employing the same type of etchant, the plurality of wet process may share the same etchant. In an established production process, an etchant is shared in an attempt to reduce the total number of etchant vessels used in a wet process. Such etchant sharing has been applied to a commercial production process after demonstrating that it does not affect properties or reliability of a semiconductor device produced.
It is ideal to optimize a cleaning-apparatus line configuration used in a series of wet processes, particularly to reduce the total number of etchant vessels by etchant sharing, after such a demonstration test. A demonstration test, however, often takes much time. For example, when replacing a particular material composing a semiconductor device with another material because of change of design, a wet process in which an etchant can be shared without causing contamination derived from the newly employed material should be selected. Here, it will take a considerably longer time for application to a commercial production process, if suitability of the selection is determined based on demonstration test results including its effects on reliability in device properties. Furthermore, while the laboratory level of demonstration test, an additional demonstration test simulating a mass production line is required in a trial production line, which takes more time.
Therefore, when there is not enough time to fully conduct the above demonstration test, an etchant to be in contact with a newly employed material is separated from etchants used in the other wet processes to avoid etchant sharing. By avoiding etchant sharing as described above, possibility of cross contamination derived from a newly employed material has been physically eliminated to temporarily conduct commercial mass production. In other words, it has been a practice to use a cleaning apparatus or wet processing apparatus exclusively for an etchant to be in contact with a newly employed material for avoiding cross contamination. It has often lead to unnecessary increase in the number of apparatuses, an unnecessary apparatus cost, increase in an etchant cost, increase of an occupied area for placing an apparatus, and even increase in a cost for treating a used etchant and increase of the amount of industrial wastes subject to final disposal.
Thus, it has been desired to suggest a process for designing a cleaning-apparatus line configuration in a process for manufacturing a silicon semiconductor device, which facilitates etchant sharing while eliminating cross contamination derived from a newly employed material after a short-time investigation, for minimizing increase the above unnecessary cost increases and increase in the amount of dopants requiring final disposal as much as possible.
An objective of this invention resolving the above problems is to provide a process for selecting in a short time a wet process treatment in which an etchant can be shared based on a minimum preliminary, investigation and which does not require a long-time demonstration test for investigating etchant sharing while eliminating cross contamination derived from a newly employed material, i.e., a process for designing a cleaning-apparatus line configuration in a process for manufacturing a semiconductor device, which appropriately facilitates etchant sharing. More specifically, an objective of this invention is to provide a process for selecting a wet process or cleaning treatment in which an etchant can be shared based on simple selection criteria and procedures and which utilizes only a few of preliminary investigation results while substantially eliminating cross contamination derived from a newly employed material, when employing the new material because of change of design on the basis of a series of wet processes and a cleaning-apparatus line configuration constituting an established manufacturing process in which an etchant is optimally shared. Another objective of this invention is to provide a process for selecting a wet process or cleaning treatment according to convenient selection criteria or procedures, in which an etchant can be shared, substantially eliminating cross contamination by adding an additive substantially without changing an etchant composition when cross contamination derived from a new material is concerned in a previously employed etchant as a result of selection of a wet process or cleaning treatment in which an etchant can be shared, on the basis of a few of preliminary investigation results described above.
Further objective of this invention is to provide a cleaning apparatus which is designed by applying the above process for designing a cleaning-apparatus line configuration in a process for manufacturing a semiconductor device and which can conduct required various cleaning procedures without significant reduction in a cleaning effect in a smaller number of apparatuses. Further objective of this invention is to provide a process for manufacturing a semiconductor device, using a more effective wet process configuration, which employs an optimized cleaning apparatus and cleaning procedure designed by applying the above process for designing a cleaning-apparatus line configuration in a process for manufacturing a semiconductor device.
This invention provides a process for designing a cleaning-apparatus line configuration used in a wet process in a process for manufacturing a semiconductor device, comprising the steps of:
estimating a presumed concentration of dissolved contaminant elements accumulated in the same etchant used in a plurality of wet processes;
estimating a residual amount of the contaminant elements adhering to a substrate from the estimated concentration of dissolved contaminants;
evaluating sharing of the etchant in the plurality of wet processes when the estimated residual amount of the contaminant elements is less than a given reference value which is the highest value where device properties are not affected; and
conducting sharing of the etchant in a cleaning-apparatus line configuration used in a wet process on the basis of the decision.
More specifically, this invention provides a process for designing a cleaning-apparatus line configuration used in a wet process in a process for manufacturing a semiconductor device, wherein on the basis of results obtained by conducting, for various materials constituting the semiconductor device, the following preliminary tests:
(a) a dissolution test for determining whether the materials are dissolved in an etchant for all etchants used in two or more wet processes in the manufacturing process;
(b) a dissolution rate test assessing the etchant dissolving the material for the amount of the dissolved material per a unit area of the material and a unit time;
(c) an adhesion property test comprising the steps of dissolving ion or molecule species generated when dissolving the material, to a given high concentration in the etchant; immersing a clean substrate in the high concentration solution for a given time; then removing the etchant by washing with a usual procedure; and determining presence of adhering residual elements derived from the material on the substrate surface;
(d) an adhesion-property concentration dependency test where for an element derived from the material which has been determined to remain by adhesion in the adhesion property test, a correlation is determined between the concentration of the dissolved element in the etchant and its surface density adhering to the substrate surface;
(e) an effective adhesion-inhibitor selection test comprising the step of determining a re-adhesion inhibiting agent which after being added to the etchant, forms a complex or compound with the ion or molecular species of the element derived from the material which has been determined to remain by adhesion in the adhesion property test, to reduce the adhesional residue,
sharing an etchant used in a wet process where the etchant is inevitably in contact with the material between the process and another wet process is evaluated in a manner that considering the following selection criteria:
(i) an etchant which is determined not to dissolve the material in the dissolution test in (a);
(ii) an etchant which is determined that there are no residues by adhesion in the adhesion property test in (c);
(iii) an etchant which has been determined that there are residues by adhesion in the adhesion property test in (c) and which is determined that an estimated adhesion surface density is less than a given contaminant surface density limit within which the properties of the semiconductor device are not deteriorated, by calculating an estimated concentration of dissolved ion or molecular species of an element derived from the material accumulated by dissolution in the etchant when processing a given number of substrates according to the structure of the semiconductor device, based on the dissolution rate obtained in the dissolution rate test in (b) and determining the estimated adhesion surface density from the estimated dissolution concentration, based on the correlation between the dissolution concentration in the etchant determined in the adhesion-property concentration dependency test in (d) and the surface density of the residues adhering to the silicon substrate surface;
(iv) an etchant containing a re-adhesion inhibitor, which is evaluated that in the selection criterion in (iii) the estimated adhesion surface density is equal to or higher than the contaminant surface density limit and is evaluated in a re-estimation that an estimated adhesion surface density becomes lower than the contaminant surface density limit by adding the re-adhesion inhibitor which is determined to be effective in the effective adhesion-inhibitor selection test in (e),
an etchant meeting the selection criteria (i) to (iii) can be shared; an etchant further meeting the selection criterion (iv) can be shared after adding the re-adhesion inhibitor determined to be effective, or otherwise an remaining etchant can be shared only in wet processes where the etchant is not inevitably in contact with a material which may be a source of an element suspected to cause deterioration of the properties of the semiconductor device, and
according to the evaluation, etchant sharing is employed in a cleaning-apparatus line configuration used in a wet process.
For example, the upper limit in a distribution range of a surface density of an element derived from the material, which is present on a substrate by immersing a clean substrate in an etchant free from the ion or molecule species of an element derived from the material for a given period and removing the etchant by a usual washing procedure, may be chosen the given contaminant surface density limit, which does not cause deterioration of the properties of the semiconductor device. Such selection of the contaminant surface density limit is usually preferable because it may reliably eliminate cross contamination.
Particularly, the process for designing a cleaning-apparatus line configuration of this invention is useful when the various materials constituting the semiconductor device include a material which may cause property deterioration when an element derived from the material adheres to a substrate surface before the step handling the material. For example, the designing process is particularly preferable when the various materials include cobalt or cobalt silicide.
Furthermore, the designing process of this invention is more suitable when the etchant employed in two or more wet processes in the process for manufacturing a semiconductor device is an ammonium hydroxide-hydrogen peroxide mixture (APM), a sulfuric acid-hydrogen peroxide mixture (SPM), diluted hydrofluoric acid,(DHF), an ammonium fluoride buffer-hydrofluoric acid mixture(BHF: buffered HF), a hydrofluoric acid-hydrogen peroxide mixture (FPM), 50% hydrofluoric acid(HF), a hydrochloric acid-hydrogen peroxide mixture (HPM), phosphoric acid and/or hydrofluoric-nitric acid (a hydrofluoric acid-nitric acid mixture).
This invention also provides, a process for designing a cleaning-apparatus line configuration where a wafer on which a semiconductor device is formed is cleaned with an etchant in a process for manufacturing a semiconductor device, wherein the manufacturing process comprises a step of cleaning the wafer on which a material used in the semiconductor device is exposed, with a given etchant, and comprising the steps of:
estimating a dissolution concentration of the material exposed on the wafer surface in the etchant;
determining a surface density of the material adhering to the wafer when immersing the wafer in the etchant in which the material is dissolved at the estimated dissolution concentration for a given period;
evaluating that the etchant can be shared in another cleaning step when the adhesion surface density is lower than a given contaminant surface density limit defined according to whether the adhesion surface density affects the properties of the semiconductor device;
evaluating that the etchant cannot be shared in another cleaning step when the adhesion surface density is higher than a given contaminant surface density limit; and
designing a cleaning-apparatus line configuration according to the evaluation results.
In the designing process, the step of estimating the dissolution concentration may comprise estimating a concentration corresponding to an accumulated concentration by dissolution of ion or molecule species of an element derived from the material when cleaning a given number of wafers on which the material is exposed for a given period.
Alternatively, the step of estimating the dissolution concentration may comprise the steps of:
estimating an amount of the material dissolved in the etchant per a unit area and a unit time as a dissolution rate test; and
estimating the dissolution concentration by multiplying the dissolution rate obtained in the dissolution rate test by the sum of the area where the material is exposed on the surface of the mass-production wafer used for a given mass production and by the sum of the time for cleaning the mass-production wafer until the etchant is replaced.
In the step of estimating dissolution concentration, the wafer on which the material is exposed may be a mass-production wafer used in mass production, or a wafer in which the material is surface-processed as in the mass-production wafer and on which the material is exposed in an area equal to or larger than that in the mass-production wafer.
Furthermore, in the step of determining the adhesion surface density, the adhesion surface density may be determined after adding a re-adhesion inhibitor which forms a complex with ion or molecule species of an element derived from the material. Alternatively, in the step of determining an adhesion density, the adhesion surface density may be determined by
when ion or molecule species of an element derived from the material are dissolved in the etchant at various given concentrations, determining a surface density of the material adhering to the wafer after immersing the wafer in the etchant at each the given concentration for a given period to determine a correlation between the given concentration and the adhesion surface density on the wafer; and
determining a surface density of the material adhering to the wafer after immersing the wafer in the etchant at a given concentration for a given period on the basis of the correlation.
This invention also provides a cleaning-apparatus line configuration designed according to any of the above designing processes.
The cleaning-apparatus line configuration of this invention is characterized in that an etchant is shared according to the above designing process. More specifically, this invention provides a cleaning-apparatus line configuration used in a wet process in a process for manufacturing a semiconductor device, wherein on the basis of results obtained by conducting, for various materials constituting the semiconductor device which are subject to wet processes in the cleaning-apparatus, the following preliminary tests:
(a) a dissolution test for determining whether the materials are dissolved in an etchant used in two or more wet processes in the manufacturing process;
(b) a dissolution rate test assessing the etchant dissolving the material for the amount of the dissolved material per a unit area of the material and a unit time;
(c) an adhesion property test comprising the steps of dissolving ion or molecule species generated when dissolving the material, to a given high concentration in the etchant; immersing a clean substrate in the high concentration solution for a given time; then removing the etchant by washing with a usual procedure; and determining presence of adhering residual elements derived from the material on the substrate surface;
(d) an adhesion-property concentration dependency test where for an element derived from the material which has been determined to remain by adhesion in the adhesion property test, a correlation is determined between the concentration of the dissolved element in the etchant and its surface density adhering to the substrate surface;
(e) an effective adhesion-inhibitor selection test comprising the step of determining a re-adhesion inhibiting agent which after being added to the etchant, forms a complex or compound with the ion or molecular species of the element derived from the material which has been determined to remain by adhesion in the adhesion property test, to reduce the adhesional residue,
sharing an etchant used in a wet process where the etchant is inevitably in contact with the material between the process and another wet process is evaluated in a manner that classifying the etchant according to the selection criteria consisting of the following (i) to (iv):
(i) an etchant which is determined not to dissolve the material in the dissolution test in (a);
(ii) an etchant which is determined that there are no residues by adhesion in the adhesion property test in (c);
(iii) an etchant which has been determined that there are residues by adhesion in the adhesion property test in (c) and which is determined that an estimated adhesion surface density is less than a given contaminant surface density limit within which the properties of the semiconductor device are not deteriorated, by calculating an estimated concentration of dissolved ion or molecular species of an element derived from the material accumulated by dissolution in the etchant when processing a given number of substrates according to the structure of the semiconductor device, based on a dissolution rate obtained in the dissolution rate test in (b) and determining the estimated adhesion surface density from the estimated dissolution concentration, based on the correlation between the dissolution concentration in the etchant determined in the adhesion-property concentration dependency test in (d) and the surface density of the residues adhering to the silicon substrate surface;
(iv) an etchant containing a re-adhesion inhibitor, which is determined that in the selection criterion in (iii) the estimated adhesion surface density is equal to or higher than the contaminant surface density limit and is determined in a re-estimation that an estimated adhesion surface density is lower than the contaminant surface density limit by adding the re-adhesion inhibitor which is determined to be effective in the effective adhesion-inhibitor selection test in (e), and
an etchant is shared in a cleaning-apparatus line configuration used in a wet process such that an etchant meeting the selection criteria (i) to (iii) can be shared; an etchant further meeting the selection criterion (iv) can be shared after adding the re-adhesion inhibitor determined to be effective, or otherwise an remaining etchant can be shared only in wet processes where the etchant is not inevitably in contact with a material which may be a source of an element suspected to cause deterioration of the properties of the semiconductor device.
For example, may be the upper limit in a distribution range of a surface density of an element derived from the material, which is present on a substrate by immersing a clean substrate in an etchant free from the ion or molecule species of an element derived from the material for a given period and removing the etchant by a usual washing procedure, may be chosen a given contaminant surface density limit, which does not cause deterioration of the properties of the semiconductor device. Such selection of the contaminant surface density limit is preferable because it may reliably eliminate cross contamination and usually used in manufacturing a wider range of semiconductor devices.
Particularly, the cleaning-apparatus line configuration of this invention is useful when the various materials constituting the semiconductor device include a material which may cause property deterioration when an element derived from the material adheres to a substrate surface before the step handling the material. For example, the line configuration is particularly preferable when the various materials include cobalt or cobalt silicide.
Furthermore, the line configuration of this invention is more suitable when the etchant employed in two or more wet processes in the process for manufacturing a semiconductor device where processing is conducted in the cleaning-apparatus line configuration is only an ammonium hydroxide-hydrogen peroxide mixture (APM), a sulfuric acid-hydrogen peroxide mixture (SPM), diluted hydrofluoric acid (DHF), an ammonium fluoride buffer-hydrofluoric acid mixture(BHF: buffered HF), a hydrofluoric acid-hydrogen peroxide mixture (FPM), 50% hydrofluoric acid(HF) and/or a hydrochloric acid-hydrogen peroxide mixture (HPM).

Cleaning-apparatus line configuration and designing process therefor


Improvements to wind farms and wind generators for harnessing wind energy or generating electricity from wind. Secondary wind turbines are provided at particular locations within a wind farm to generate additional electricity, in some embodiments, using a common electrical power collection system. Enclosures or venturis may surround wind turbines to facilitate mounting close to the ground. Venturis may accelerate wind speed through the turbine and may have a particular shape, may be made of particular materials arranged in particular ways, or both. In different embodiments, wind turbines may be axial-flow horizontal-axis turbines, or may be Savonius turbines, as examples. And in some embodiments, wind turbines may be combined with other power production equipment, such as solar power equipment, for instance.

Wind energy has been harnessed for centuries and used for a variety of useful purposes including propelling sailing ships to newly discovered continents, grinding grain, pumping water, and generating electricity. In recent times, large propeller-type horizontal axis turbines have been mounted on towers and used to turn electrical generators to provide a portion of the power for a large electrical distribution grid. Significant numbers of these wind turbines have been located in particular areas with high average wind speeds to form wind farms with considerable generating capability. Wind turbines have also been used to generate electricity in off-grid applications such as remote sites.
Wind energy is a potential substitute for at least a portion of the power generated by burning fossil fuels in conventional power plants, and use of wind energy instead of fossil fuels reduces the production of atmospheric pollution that otherwise would result from burning fossil fuels. In addition to the traditional pollutants from burning of fossil fuels, such as hydrocarbons, carbon monoxide, particulates, and acid rain, as examples, use of wind energy reduces the production of greenhouse gasses (i.e., carbon dioxide), in comparison with fossil fuels, and the contribution to the risks and potential harm associated with global warming. Further, use of wind energy reduces the need for the sacrifice of land for open pit mining and the risk to underground workers associated with underground mining of fossil fuels such as coal, or nuclear reactor fuels such as uranium, as examples. Use of wind energy instead of nuclear power also helps to avoid the risk of accidents and terrorist acts, as well as the long-term commitment of future generations associated with the production of radioactive waste.
According to the American Wind Energy Association, the U.S. Department of Energy has estimated that the wind energy potential in the U.S., for example, exceeds the total U.S. electrical consumption today. However, certain locations are far better than others for locating devices that harness wind energy, and available locations with adequate and relatively consistent wind speeds are limited. Further, state-of-the-art wind turbines usually must be spaced apart from one another by a fairly substantial distance to avoid overly impacting the flow of the wind to adjacent turbines. Consequently, the number of wind turbines that have been installed in a particular area of land has been rather limited. Thus, a need exists, or potential for benefit, to be able to improve the power production capability of a new or existing wind farm, or of a particular area of available land. Further, needs and potential for benefit exist for a wind farm that allows greater power production per area of land, more wind turbines per area of land, less interference between adjacent wind turbines, or wherein adjacent turbines improve wind speeds through each other, at least in some cases, rather than reducing wind speeds through each other.
Additionally, prior art horizontal-axis wind turbines are typically mounted on a tall tower. In addition to accessing higher wind speeds, the height of traditional wind turbines reduces or avoids risk to people, livestock, and wildlife, that may be on or near the ground. But towers are expensive to build and, at least in some cases, their height may be objectionable, for example, for obstructing a view. Thus, needs and potential for benefit exist for a wind turbine that will work well near the ground without putting people, livestock, or wildlife at excessive risk. In addition, flying birds are often killed or injured by traditional exposed wind turbines, and needs and potential for benefit exist, especially in certain locations, for wind turbines that protect birds from harm or that reduce the risk to birds inhabiting or passing through the area.
Further, due to the large size of the blades, and limitations on tip speeds, for example, prior art horizontal-axis wind turbines typically require a speed increaser between the turbine and the generator. Speed increasers have equipment costs, frictional losses, maintenance requirements, and risks of breakdown associated with them. Large blades are also an expensive component of existing wind turbines, and require high towers, which are another expensive component. Thus, needs and potential for benefit exist for a wind turbine in which the propeller turns at a higher speed so that a speed increaser is not required, need not increase the speed as much (e.g., proportionally), or need not handle as much torque (e.g., be as large), particularly while meeting other needs and potential areas for benefit. Needs and potential for benefit also exist for a wind turbine having smaller blades.
Still further, wind energy production has been increasing dramatically around the world in recent years. In response to the demand, installed costs for horizontal-axis wind turbines have increased on a per KWH basis as the best sites have been utilized, for example. In addition, increasing demand on limited wind turbine production capacity has resulted in both increases in cost and delays in obtaining specialized wind turbine equipment. As a result, needs and potential for benefit exist for alternative configurations of wind turbines that utilize different construction methodologies, that require different construction facilities, that compliment rather than competing directly with existing horizontal-axis wind turbine designs, and that are competitive with prior art technology on a cost per KWH basis, delivery time basis, or both. Furthermore, needs and potential for benefit exist for alternative configurations of wind turbines that facilitate faster or less expensive manufacturing and implementation of wind energy production capability on a worldwide basis.
Even further, structures have been proposed for focusing wind onto a turbine. U.S. Pat. No. 6,710,468 (Marreo O'Shanahan) concerns a wind-channeling conduit with a rotor within a narrowing in the conduit. U.S. Pat. No. 1,471,095 (Bonetto) shows two funnels 16 and 17 between which are blades 27 which turn a shaft 29. And U.S. Pat. No. 3,883,750 (Uzzell) shows a fan within a venturi, while U.S. Pat. No. 4,021,135 (Pedersen) shows a rotor 14 within a cowling 17. However, needs and potential for benefit exist for a venturi that has a shape that further reduces losses as air passes through the venturi. In addition, vertical axis and Savonius-type rotors or wind turbines have been proposed in the prior art. Bonetto, U.S. Pat. No. 4,474,529 (Kinsey), U.S. Pat. Nos. 5,332,354, and 5,852,331 show various vertical axis wind turbines. Further, U.S. Pat. No. 6,538,340 (Elder) contemplates use of a sandwich material for construction of wind turbine systems. Potential for improvement exists in these and other areas that may be apparent to a person of skill in the art having studied this document.

Wind energy harnessing apparatuses, systems, methods, and improvements


An improved method of nuclear transfer involving the transplantation of donor differentiated pig cell nuclei into enucleated pig oocytes is provided. The resultant nuclear transfer units are useful for multiplication of genotypes and transgenic genotypes by the production of fetuses and offspring. Production of genetically engineered or transgenic pig embryos, fetuses and offspring is facilitated by the present method since the differentiated cell source of the donor nuclei can be genetically modified and clonally propagated.

The use of ungulate inner cell mass (ICM) cells for nuclear transplantation has also been reported. For example, Collas et al., Mol. Reprod. Dev., 38:264-267 (1994) discloses nuclear transplantation of bovine ICMs by microinjection of the lysed donor cells into enucleated mature oocytes. Collas et al. disclosed culturing of embryos in vitro for seven days to produce fifteen blastocysts which, upon transferral into bovine recipients, resulted in four pregnancies and two births. Also, Keefer et al., Biol. Reprod., 50:935-939 (1994), disclosed the use of bovine ICM cells as donor nuclei in nuclear transfer procedures, to produce blastocysts which, upon transplantation into bovine recipients, resulted in several live offspring. Further, Sims et al., Proc. Natl. Acad. Sci., USA, 90:6143-6147 (1993), disclosed the production of calves by transfer of nuclei from short-term in vitro cultured bovine ICM cells into enucleated mature oocytes.
The production of live lambs following nuclear transfer of cultured embryonic disc cells has also been reported (Campbell et al., Nature, 380:64-68 (1996)). Still further, the use of bovine pluripotent embryonic cells in nuclear transfer and the production of chimeric fetuses has been reported (Stice et al., Biol. Reprod., 54:100-110 (1996); Collas et al., Mol. Reprod. Dev., 38:264-267 (1994)). Collas et al. demonstrated that granulosa cells (adult cells) could be used in a bovine cloning procedure to produce embryos. However, there was no demonstration of development past early embryonic stages (blastocyst stage). Also, granulosa cells are not easily cultured and are only obtainable from females. Collas et al. did not attempt to propagate the granulosa cells in culture or try to genetically modify those cells. Wilmut et al. (Nature, 365:810-813 (1997)) produced nuclear transfer sheep offspring derived from fetal fibroblast cells, and one offspring from a cell derived from an adult sheep.
Cloning pig cells is more difficult in comparison with cells of other species. This phenomenon is illustrated by the following table:
SPECIES (from hardest toOFFSPRINGeasiest to clone)CELL TYPE CLONEDPRODUCEDPig (Prather, 1989)2 and 4 cell stage embryoyesPig (Prather, 1989; Liu et al.,greater than 4 cell stageno1995)Mouse (Cheong et al., 1993)2, 4 and 8 cell stageyesembryoMouse (Tsunoda et al., 1993)greater than 8 cell stagenoCattle (Keefer et al., 1994)64 to 128 cell stageyes(ICM)Cattle (Stice et al., 1996)embryonic cell line fromnoICMSheep (Smith et al., 1989)64 to 128 cell stageyes(ICM)Sheep (Campbell et al., 1996)embryonic cell line fromyesICMSheep (Wilmut et al., 1997)fetal and adult cellsyes
There also exist problems in the area of producing transgenic pigs. By current methods, heterologous DNA is introduced into either early embryos or embryonic cell lines that differentiate into various cell types in the fetus and eventually develop into a transgenic animal. However, many early embryos are required to produce one transgenic animal and, thus, this procedure is very inefficient. Also, there is no simple and efficient method of selecting for a transgenic embryo before going through the time and expense of putting the embryos into surrogate females. In addition, gene targeting techniques cannot be easily accomplished with early embryo transgenic procedures.
Embryonic stem cells in mice have enabled researchers to select for transgenic cells and perform gene targeting. This allows more genetic engineering than is possible with other transgenic techniques. However, embryonic stem cell lines and other embryonic cell lines must be maintained in an undifferentiated state that requires feeder layers and/or the addition of cytokines to media. Even if these precautions are followed, these cells often undergo spontaneous differentiation and cannot be used to produce transgenic offspring by currently available methods. Also, some embryonic cell lines have to be propagated in a way that is not conducive to gene targeting procedures.
Methods for deriving embryonic stem (ES) cell lines in vitro from early preimplantation mouse embryos are well known. (See, e.g., Evans et al., Nature, 29:154-156 (1981); Martin, Proc. Natl. Acad. Sci., USA, 78:7634-7638 (1981)). ES cells can be passaged in an undifferentiated state, provided that a feeder layer of fibroblast cells (Evans et al., Id.) or a differentiation inhibiting source (Smith et al., Dev. Biol., 121:1-9 (1987)) is present.
ES cells have been previously reported to possess numerous applications. For example, it has been reported that ES cells can be used as an in vitro model for differentiation, especially for the study of genes which are involved in the regulation of early development. Mouse ES cells can give rise to germline chimeras when introduced into preimplantation mouse embryos, thus demonstrating their pluripotency (Bradley et al., Nature, 309:255-256 (1984)).
In view of their ability to transfer their genome to the next generation, ES cells have potential utility for germline manipulation of livestock animals by using ES cells with or without a desired genetic modification. Moreover, in the case of livestock animals, e.g., ungulates, nuclei from like preimplantation livestock embryos support the development of enucleated oocytes to term (Smith et al., Biol. Reprod., 40:1027-1035 (1989); and Keefer et al., Biol. Reprod., 50:935-939 (1994)). This is in contrast to nuclei from mouse embryos which beyond the eight-cell stage after transfer reportedly do not support the development of enucleated oocytes (Cheong et al., Biol. Reprod., 48:958 (1993)). Therefore, ES cells from livestock animals are highly desirable because they may provide a potential source of totipotent donor nuclei, genetically manipulated or otherwise, for nuclear transfer procedures.
Some research groups have reported the isolation of purportedly pluripotent embryonic cell lines. For example, Notarianni et al., J. Reprod. Fert. Suppl., 43:255-260 (1991), reports the establishment of purportedly stable, pluripotent cell lines from pig and sheep blastocysts which exhibit some morphological and growth characteristics similar to that of cells in primary cultures of inner cell masses isolated immunosurgically from sheep blastocysts. Also, Notarianni et al., J. Reprod. Fert. Suppl., 41:51-56 (1990) discloses maintenance and differentiation in culture of putative pluripotential embryonic cell lines from pig blastocysts. Gerfen et al., Anim. Biotech, 6(1):1-14 (1995) discloses the isolation of embryonic cell lines from porcine blastocysts. These cells are stably maintained in mouse embryonic fibroblast feeder layers without the use of conditioned medium, and reportedly differentiate into several different cell types during culture.
Further, Saito et al., Roux's Arch. Dev. Biol., 201:134-141 (1992) reports cultured, bovine embryonic stem cell-like cell lines which survived three passages, but were lost after the fourth passage. Handyside et al., Roux's Arch. Dev. Biol., 196:185-190 (1987) discloses culturing of immunosurgically isolated inner cell masses of sheep embryos under conditions which allow for the isolation of mouse ES cell lines derived from mouse ICMs. Handyside et al. reports that under such conditions, the sheep ICMs attach, spread, and develop areas of both ES cell-like and endoderm-like cells, but that after prolonged culture only endoderm-like cells are evident.
Recently, Cherny et al., Theriogenology, 41:175 (1994) reported purportedly pluripotent bovine primordial germ cell-derived cell lines maintained in long-term culture. These cells, after approximately seven days in culture, produced ES-like colonies which stained positive for alkaline phosphatase (AP), exhibited the ability to form embryoid bodies, and spontaneously differentiated into at least two different cell types. These cells also reportedly expressed mRNA for the transcription factors OCT4, OCT6 and HES1, a pattern of homeobox genes which is believed to be expressed by ES cells exclusively.
Also recently, Campbell et al., Nature, 380:64-68 (1996) reported the production of live lambs following nuclear transfer of cultured embryonic disc (ED) cells from day nine ovine embryos cultured under conditions which promote the isolation of ES cell lines in the mouse. The authors concluded that ED cells from day nine ovine embryos are totipotent by nuclear transfer and that totipotency is maintained in culture.
Van Stekelenburg-Hamers et al., Mol. Reprod. Dev., 40:444-454 (1995), reported the isolation and characterization of purportedly permanent cell lines from inner cell mass cells of bovine blastocysts. The authors isolated and cultured ICMs from 8 or 9 day bovine blastocysts under different conditions to determine which feeder cells and culture media are most efficient in supporting the attachment and outgrowth of bovine ICM cells. They concluded that the attachment and outgrowth of cultured ICM cells is enhanced by the use of STO (mouse fibroblast) feeder cells (instead of bovine uterus epithelial cells) and by the use of charcoal-stripped serum (rather than normal serum) to supplement the culture medium. Van Stekelenburg et al. reported, however, that their cell lines resembled epithelial cells more than pluripotent ICM cells.
Smith et al., WO 94/24274, published Oct. 27, 1994, Evans et al., WO 90/03432, published Apr. 5, 1990, and Wheeler et al., WO 94/26889, published Nov. 24, 1994, report the isolation, selection and propagation of animal stem cells which purportedly may be used to obtain transgenic animals. Evans et al. also reported the derivation of purportedly pluripotent embryonic stem cells from porcine and bovine species which assertedly are useful for the production of transgenic animals. Further, Wheeler et al., WO 94/26884, published Nov. 24, 1994, disclosed purported embryonic stem cells which are assertedly useful for the manufacture of chimeric and transgenic ungulates.
Thus, based on the foregoing, it is evident that many groups have attempted to produce ES cell lines, e.g., because of their potential application in the production of cloned or transgenic embryos and in nuclear transplantation.
Therefore, notwithstanding what has previously been reported in the literature, there exists a need for improved methods of cloning pigs using cultured differentiated cells as donor nuclei.

This patent is subject to a terminal disclaimer.

Cloning pigs using non-quiescent differentiated donor cells or nuclei

University of Massachusetts, a Public Institution of Higher Education of the Commonwealth of Massachusetts, as Represented by its Amherst Campus, Office of Vice Chancellor for Research at Amherst


A thermoplastic case which has an interlocking bottom peripheral edging (20) with a lobe (26) on the outside surface to which a vacuum formed bottom (28) has been conformed completely enveloping the lobe creating a structural bond for fastening the two parts together. A lid edging (30) and case lid (38) are formed in the same manner completing the case. A resilient cord (46) may be added to assure the seal between the edgings and a bonding agent in the form of cement (50) or tape (52) may be employed to complete a hermetic seal for the case. Webbing (56) may optionally be added formed integrally with the edging for suspending articles within the case.

Previously many types of edging have been used in endeavoring to provide an effective means of joining the sealing member of the bottom half of a case to the top half or lid. The attachment of this edging member to the case, particularly the vacuum formed type, has been accomplished using fasteners, bonding with adhesive, captivating between contiguous appendages or even forming the edging as an integral part of the case.
A search of the prior art did not disclose any patents that read directly on the claims of the instant invention however, the following U.S. patents were considered:
______________________________________ PAT. NO. INVENTOR ISSUED ______________________________________ 4,284,202 Barstow, Jr. 18 August 1981 4,095,719 Wolf 20 January 1978 3,513,951 Leong, et al 26 May 1970 3,088,623 Parker 7 May 1963 2,969,891 Presnick 31 January 1961 2,510,643 Long 6 June 1950 also Great Britain 1,403,092 Roper Corp. 13 August 1975 1,068,453 Schmid 10 May 1967 ______________________________________
In the patent No. 4,284,202 issued to Barstow, Jr. a container is disclosed that uses a base and lid joined together with a tongue and groove arrangement. The base and lid include integrally formed interlocking portions without the use of separate case edging.
Wolf uses an edge extrusion attached on the peripheral rim and to the sidewall the shell of a plastic container the edge extrusion includes a rubber gasket. The top and bottom of the case are inserted into grooves in the extrusion and crimped in place. The internal groove contains a plurality of ridges helping to secure the case after it is crimped.
Leong, et al teach a vacuum formed luggage case and a protecting frame or valance strip secured by crimping about the perimeter of each shell. The frame contains a channel and the shell edge portion within the channel is at a substantial angle approaching right angular relationship providing strength and stability.
Parker employs the same channel like structure of extruded metal except with complimentary sealing devices arranged to be held in contacting relationship with each other to form a seal. The walls of the case are bonded and a resilient pressure strip is integrally exerting outward pressure on the sides assisting to hold them in place along with the bonding.
Presnick in U.S. Pat. No. 2,969,811 attaches a peripheral molding strip using bonding resins deposited in a cavity between the case wall and molding in combination with circumferential welding. The heat of the fusion welding does not affect the resin as it is contained within the cavity away from the point of heat concentration.
Schmid in patent No. 1,068,453 issued in Great Britain utilizes a metal profile frame around a box. The frames have flanges on their inner side with saw toothed serrations which hook into the rims, which may be leather or the like. Also the rims are folded over their edge by rolling deforming the metal into a gripping profile engaging the body of the box.
For background purposes and as indicative of the art to which the invention relates, reference may be made to the remaining cited patents issued to Long and Roper Corporation.
It may be clearly seen that prior art fully realizes the problem of attachment of a separate edging to some type of case however, encapsulating the case body during the vacuum forming process is entirely new and unique.


Provided is an optical information medium which permits the reading and writing of optical information by actively using polarized light. The optical information medium comprises an information layer containing a compound which undergoes a change upon irradiation with circularly polarized light to provide a new product which is optically active, and which is distinguishable from the original compound in its interaction with polarized light. In a preferred embodiment, the optical medium comprises optical isomers which can be selectively photolyzed by circularly polarized light. While writing must be done using a circularly polarized light source, reading of the recorded information can be accomplished using either circularly polarized light or linearly polarized light.

The present invention relates to a method of recording and reading optical information. More specifically, the present invention relates to the use of the photochiroptical effect in the recording and reading of optical information. The present invention also relates to a novel optical information medium for use in the method of recording and reading optical information.
A wide variety of means exists for the writing and retrieval of optical information. All of these methods involve a change in the optical characteristics of certain portions of an information layer during the writing process, with those changes being noted during the reading process. The use of an isomerization process for effecting the change in optical characteristics has been suggested, as has the switching of the optical storage material in the information layer to a plurality of oxidation states. This latter process has a potential of providing a ternary storage system.
For example, U.S. Pat. No. 4,663,270 issued to Potember et al, discloses a multistate organic optical storage medium wherein an optical beam can switch any data storage spot into three or more memory states. The storage medium consists of a mixture of bistate switching modules, or of large delocalized amphoteric molecules. The illuminated area of the optical storage medium undergoes an electrochemical topatic redox reaction thereby causing certain moieties in the illuminated area to change oxidation state. By changing the intensity of the optical "write" beam the illuminated area can be switched to a plurality of specific states with each state having a unique set of oxidation species. A ternary system can thereby be theoretically realized.
The use of isomerization as a technique in recording information in an optical medium is disclosed, for example, in U.S. Pat. No. 4,678,736 issued to Hanamura et al. The information bits are recorded by applying energy to a polydiacetylene thin film supported by a substrate, so that the main chain structure of the polydiacetylene is transformed into another form or forms. The changes are, more specifically, from the A-type bonding to the B-type bonding, and additionally from a planar configuration to a non-planer configuration. This change in form also results in a change of optical characteristics, which permits one to read the information recorded.
U.S. Pat. No. 4,686,169 issued to Yoshino et al relates to an optical disk structure in which an information layer of a photochromic dye is irradiated by laser light in order to record information. The photochromic dye exhibits the photochromizum based on a cis-trans isomerization. Such photochromic compounds include the amphipathic derivative of azobenzene, indigo or thioindigo. The dyes are stable in both the cis and trans forms, and the recorded information bit is read based upon the different light absorption spectra resulting from the two different forms.
The search continues, however, for improved systems in the recording and retrieval of optical information. The need for increased storage capacity, as well as improvements in the areas of error detection and correction, are necessary in order to provide a commercially viable system. To provide such a system is an object of the present information.
Other objects of the present invention will become apparent upon a review of the following specification and the claims appended hereto.

Storage of optical information using photochiroptical effect


A humidification device includes a humidification section that humidifies taken-in air and a cover that covers the humidification section. A space is provided between the humidification section and the cover. A supply port for sending out humidified air humidified by the humidification section is further provided. The space communicates with the supply port, and the humidified air flows through the space, thereby utilizing air in the space as a heat insulation layer.

JP2011-60638A (Reference 1) proposes, as a humidification device, a configuration in which a plurality of fuel battery cells are sandwiched between two end plates, and a humidification device (a humidifier in the Reference 1) is provided at an outer surface of one of the two end plates.
The humidification device described in the Reference 1 is configured so as to be attached to the outer surface of the end plate and to supply humidified air to a fuel cell unit via a conduit (a connection pipe in the Reference 1).
For example, the humidified air to be supplied to the fuel battery cells needs to have a predetermined temperature. Particularly, when the humidification device has a configuration easily dissipating heat, a temperature decrease accompanying the heat dissipation causes a decline in electric power generation performance of the fuel battery cells. Further, in the configuration of supplying humidified air via a conduit as described in the Reference 1, an additional component used in the conduit is necessary, and for this reason, the number of components increases, a step for making connection of the conduit is further necessary, and thus room for improvement exists.
A need thus exists for a humidification device which is not susceptible to the drawback mentioned above.


To provide a liquid crystal compound having a large negative value of dielectric anisotropy (Δ∈). A compound is represented by formula (1):

A display device using a liquid crystal compound is widely utilized for a display of a watch, a calculator, a word processor and so forth. The display devices utilize characteristics of the liquid crystal compound, such as optical anisotropy and dielectric anisotropy.
A liquid crystal phase includes a nematic liquid crystal phase, a smectic liquid crystal phase and a cholesteric liquid crystal phase, and the nematic liquid crystal phase is most widely utilized. Specific examples of display modes include a dynamic scattering (DS) mode, a deformation of aligned phases (DAP) mode, a guest/host (GH) mode, a twisted nematic (TN) mode, a super twisted nematic (STN) mode, a bistable twisted nematic (BTN) mode, a thin film transistor (TFT) mode, a vertical alignment (VA) mode, a multi-domain vertical alignment (MVA) mode, an optical compensation bend (OCB) mode, an in-plane switching (IPS) mode and a polymer sustained alignment (PSA) mode.
For the liquid crystal compound used in the display modes, characteristics such as having a liquid crystal phase in a wide temperature range centering on room temperature, being sufficiently stable under conditions in which the display device is used, and having sufficient characteristics for driving the display device are required. However, no single compound meeting the requirements is found at present.
Therefore, a liquid crystal composition meeting the requirements is prepared by mixing several kinds to several tens kinds of liquid crystal compounds. The requirements desired for the liquid crystal compound constituting the liquid crystal composition are as described below.
The requirements include:
(1) high stability to heat, light and so forth;
(2) high clearing point (clearing point: phase transition temperature between the liquid crystal phase and an isotropic phase);
(3) low minimum temperature of a liquid crystal phase such as the nematic phase and the smectic phase, particularly, a low minimum temperature of the nematic phase;
(4) suitable optical anisotropy;
(5) large dielectric anisotropy;
(6) suitable elastic constant; and
(7) excellent solubility in other liquid crystal compounds
As a display mode for overcoming narrowness of viewing angle being a biggest problem of the liquid crystal display device, among the display modes, the modes such as the IPS mode, the VA mode, the OCB mode and the PSA mode attract attention in recent years. Among the liquid crystal display devices according to the modes, in particular, the liquid crystal display device according to the IPS mode or the VA mode has a wide viewing angle and also an excellent responsiveness to further obtain a high contrast display, and thus is actively developed. Features of the liquid crystal composition used for the liquid crystal display devices according the display modes are in a negative value of dielectric anisotropy. Further, a liquid crystal composition having a large negative value of dielectric anisotropy is known to allow a decrease of driving voltage of the liquid crystal device including the liquid crystal composition (see Non-patent literature No. 1). Therefore, the liquid crystal compound being a constituent of the liquid crystal composition is also required to have a larger negative value of dielectric anisotropy.
An attempt has been made so far for increasing an absolute value of negative dielectric anisotropy in a compound having a 2,3-difluorophenylene skeleton. For example, a compound prepared by introducing a tetrahydropyran-2,5-diyl skeleton into a compound having a 2,3-difluorophenylene skeleton is reported (Patent literature No. 1). Compound (b) shows a large negative dielectric anisotropy in comparison with compound (a).

Furthermore, as a compound showing a negative dielectric anisotropy, compound (15) having a 2,3-difluoro-1,4-phenylene skeleton is generally known (Non-patent literature No. 3). In order to further increase an absolute value of negative dielectric anisotropy, compound (16) prepared by bonding trifluoromethyl on a lateral position of a molecule; and compound (17), compound (18) and compound (19) each prepared by bonding difluoromethyl on a lateral position of a molecule have been reported (Patent literature No. 2, Non-patent literature No. 2, Non-patent literature No. 3, Patent literature No. 3 and Patent literature No. 4).

In order to decrease the driving voltage of the liquid crystal display device according to the IPS mode, the VA mode or the like, a liquid crystal compound having a further large negative value of dielectric anisotropy, a liquid crystal composition containing the compound and a liquid crystal display device including the liquid crystal composition are desired.

Liquid crystal compound showing negative dielectric anisotropy, liquid crystal composition and liquid crystal display device

Abstract: wherein, in formula (1), one of Y1 and Y2 is fluorine, and the other is CF2H or CF3; G is a ring represented by formula (pr-1) or formula (pr-2):

Abstract: wherein A1 to A3 are independently 1,4-cyclohexylene or 1,4-phenylene; Ra and Rb are independently hydrogen, alkyl having 1 to 20 carbons, or the like; Z0, and Z1 to Z3 are independently a single bond, —(CH2)2—, —CH═CH—, —CF2O—, —OCF2—, —CH2O—, —OCH2—, —COO— or —OCO—; j, m and n are an integer from 0 to 2, and a sum of j, m and n is 0, 1 or 2, however, when m is 0, Y1 is CF2H or CF3, Y2 is fluorine, and Z0 is a single bond, G is a ring represented by formula (pr-1).


A shelf bracket having an open mouth in the form of a U-shaped member which is adapted to be connected to a surface and extend outwardly therefrom, the lower flange of the bracket extending beneath a shelf, when the shelf is positioned and having a brace which extends.

This invention relates to a shelf bracket and, in particular, to a shelf bracket which can be of extruded material.
There have been proposed various forms of shelf brackets which are adapted to be connected to a surface and which have a forwardly opening mouth which is adapted to receive the inner edge of a shelf and it is to brackets of this type that the present invention specifically relates.


When the information-provision apparatus is providing an audio signal to the specific information reproduction apparatus, the user enters an operation input to the specific information reproduction apparatus to switch processing to reproduce an audio content from the specific information reproduction apparatus to another information reproduction apparatus. In this case, the specific information reproduction apparatus requests the information-provision apparatus to start an operation of providing the audio content to the other information reproduction apparatus specified in the operation input as an apparatus to newly reproduce the audio content. Then, the specific information reproduction apparatus requests the information-provision apparatus to end an operation of providing the audio content to the specific information reproduction apparatus specified in the operation input as an apparatus to terminate an operation of reproducing the audio content.

The present invention relates to an information-provision control method adopted in an information reproduction system including at least one information-provision apparatus and a plurality of information reproduction apparatuses used for sequentially reproducing information provided by the information-provision apparatus, as well as relates to this information reproduction system, the information-provision apparatus, the information reproduction apparatus and an information-provision control program.
In recent years, with popularization of personal computers and the increasing number of applications of the Internet, by using a personal computer at a home or at a working place, a large number of accesses to a server connected to the Internet can be made to download a variety of content data and a large number of emails can be exchanged in a wide range of applications. In addition, the operations to download audio and video data from a server as content data by way of the Internet have been becoming regular day-to-day operations. For example, a technology has been proposed for an Internet-based chat system as a technology allowing audio data to be provided at the same time to a plurality of persons participating in a chat to be listened to by the participants in the same way as text data. For details of this technology, refer to Japanese Patent Laid-open No. 2001-184292, which is referred to as patent reference 1.
In this way, through the so-called WAN (Wide Area Network), communication technologies have been dramatically making progress to provide the user with a convenient application environment as evidenced by, among others, the fact that necessary information can be acquired in a short period of time at places such as a home and a working place whereas information can be exchanged smoothly as advancements of efforts to share information.
Moreover, in addition to the WAN system, a LAN (Local Area Network) system can be constructed as a network connecting personal computers and peripheral apparatus to each other in a limited space such as a home or rooms inside a building. The LAN system is widely used as a system for allowing users to share resources such as files and a printer.
In the conventional LAN system employing UARTs (Universal Asynchronous Receiver-Transceivers), however, a sufficiently high communication speed cannot be assured, raising a problem that, for example, it takes too long time to exchange audio data that should be transmitted at a required communication speed of about 1.4 MBps (megabytes per second).
In addition, with recent introduction of a USB (Universal Serial Bus), a personal computer becomes capable of transmitting audio data by way of a USB terminal. Nevertheless, the maximum length of its cable is fixed at 5 m. Thus, for example, even a personal computer located in the same room is not capable of playing the role of an active speaker.
With progress made in recent years in Internet technologies, however, communication using a TCP/IP (Transmission Control Protocol/Internet Protocol), which has been becoming popular, not only allows audio data to be transferred in a sufficiently short period of time given its communication speed and communication reliability, but also allows the length of a cable used in a LAN system built at a place like a home to be extended to a maximum of 100 m. Thus, sounds of music can distributed to any locations in the facility. In addition, through a piece of equipment such as a Network HUB, the number of apparatus connectable to the network can be increased.
On the top of that, if only audio data is to be transferred through a given communication band, a plurality of pieces of audio data can be transmitted once simultaneously. Thus, by providing a server having a sufficient processing power, it is possible to prepare an environment in which clients installed in a plurality of rooms are capable of listening to desired audio data being distributed at the same time from the server.
Accordingly, a personal computer installed at a home and a variety of AV (Audio/Visual) apparatus provided in rooms of the home can be connected to each other through a LAN. With such a LAN, it is possible to build an environment in which contents stored in the personal computer can be enjoyed at a variety of places such as the living room, study room and bedroom of the home. Examples of the contents are audio data, video data and AV data, which includes audio and video data collected synchronously.
Much like a WAN system, a LAN system also adopts a general method of utilization by which any client desiring information outputs a request for the information to a server used as an information provider and the server transmits the desired information to the server in response to the request. If the LAN system adopting such a method includes a plurality of clients, the clients are allowed to make accesses to the server simultaneously to receive a desired content at the same time.
By the way, the so-called home network system, which is a LAN system constructed at a home, is built in a house. Given such a home network system, the user raises a demand for a capability of enjoying a desired content in a room in which the user desires to enjoy the content. In this case, the user issues a request to typically a personal computer functioning as a server through an AV apparatus located in the room.
In addition, the user also raises a demand for a capability of allowing the user not to only listen to a desired audio content in a specific room through a particular AV apparatus, but also to continuously listen to the same audio content in another room through another AV apparatus located at the other room following a movement of the user from the specific room to the other room. On the top of that, in this case, it is desirable to merely require the user to operate only once either the particular AV apparatus in the specific room immediately before the movement or the other AV apparatus in the other room after the movement.
In the conventional home network system, however, as general operations to be carried out by the user on a particular AV apparatus in a specific room to make an access to the server to search the server for a desired content and control an operation to reproduce the content, normally, the user is capable of operating the particular AV apparatus presumably only for the purpose of reproducing the desired content in this AV apparatus. Thus, when the user moves from the specific room to another room after operating the particular AV apparatus, the user must stop the operation carried out by the particular AV apparatus to reproduce the content before the user moves from the specific room to the other room and then operate another AV apparatus installed in the other room in order to restart the operation to reproduce the desired content. Thus, from the user point of view, the operatability of the conventional home network system is poor and the operation to reproduce a content is interrupted every time the user moves from one room to another. That is to say, it is difficult to reproduce a content continuously.

Information-provision control method, information reproduction system, information-provision apparatus, information reproduction apparatus and information-presentation control program


A method for attaching a reclosable zipper strip (40) onto a sheet of thermoplastic film material (32) in the production of packages includes an apparatus (10) which has two guide plates (12, 14) that define a guide space (16). The apparatus (10) includes a pair of hole punches (26), one on either side of the guide space (16), and;a knife (24) which severs lengths of the zipper strip (40) in the guide space. The hole punches (26) and the cutting knife (24) are separated from one another by a distance equal to the length of the zipper strip (40) being attached to the sheet (32). The hole punches remove the flanges (54, 56, 58) from a preselected amount of the zipper strip (40) upstream of the knife (24).

The present invention relates to reclosable plastic bags of the type in which consumer products are packaged for retail sale. More particularly, the present invention relates to reclosable plastic bags manufactured and filled on packaging machines using a sheet of thermoplastic film material having lengths of reclosable zipper strip attached transversely thereto at package-length intervals.
The present invention relates to improvements in the package-making art and may be practiced in the manufacture of thermoplastic bags and packages of the kind that may be used for various consumer products, but which are particularly useful for food products which must be kept in moisture-tight and air-tight packages, free from leakage until initially opened for access to the package contents, and which are then reclosable by a zipper to protect any remainder of the product therein. The prior art is fairly well developed, but nevertheless has aspects worthy of improvement and refinement.
In the present case, lengths of reclosable zipper, strip are applied to a sheet of thermoplastic film advancing longitudinally therealong with the zipper strip applied transversely at package-length intervals. In the prior art, the required lengths of reclosable zipper strip are separated from a supply thereof by a cutting knife which passes through a gap in the plates used to guide the strip. Frequently, as the subsequent length of reclosable zipper strip is advanced past the gap, the strip becomes misaligned, jams or otherwise misfeeds across the gap. Such events require production to be halted while the zipper strip is correctly re-fed past the gap. The present invention provides a solution to this problem.
Accordingly, the present invention is a method for attaching a reclosable zipper strip transversely to a sheet of thermoplastic film material for use in the production of plastic bags or packages. The sheet itself has a longitudinal direction and, is incrementally advanced in that direction in amounts equal in length to that of the bags or packages being manufactured. A length of the reclosable zipper strip is transversely attached to each incremental length of the sheet.
The method starts with the step of providing a reclosable zipper strip having a male interlocking profile and a female interlocking profile. The male interlocking profile has a male interlocking member, while the female interlocking profile has a female interlocking member. One of the male and female interlocking profiles has a web integrally formed with its respective interlocking member on both lateral sides thereof. The other of the male and female interlocking profiles has a web integrally formed with its respective interlocking member on at least one lateral side thereof.
The method further includes the step of removing preselected amounts of the webs from the reclosable zipper strip at preselected intervals therealong, leaving only the interlocked male and female interlocking members at those preselected intervals. The method continues with the step of guiding the reclosable zipper strip into position for transverse attachment onto the sheet. The interlocked male and female interlocking profiles are then cut where the preselected amounts of the webs have been removed to provide desired lengths of the reclosable zipper strip. These lengths are then transversely attached onto the sheet of thermoplastic film material at package-length intervals therealong. Preferably, these lengths are attached so that they are centered on the sheet of thermoplastic film material.
The sheet of thermoplastic film material with lengths of reclosable zipper strip attached transversely thereto may either be rolled up for use at a subsequent time or fed directly to a package-making machine, such as a vertical form-fill-and-seal (VFFS) machine, to make reclosable packages and/or to fill them with a consumer product.
The production of such packages includes the additional steps of folding the sheet of thermoplastic film material so as to bring its lateral edges together, and of sealing the lateral edges to each other to form a package having front and back walls. The thermoplastic film material of the front and back walls is then sealed above and below the ends of the lengths of reclosable zipper strip where the webs have been removed to entrap the two ends of the reclosable zipper strip without having to crush them.
Finally, the webs of the male and female interlocking profiles are sealed to the thermoplastic film material without sealing them to each other, cross-seals are formed at the top of the package and at the bottom of the succeeding package, and the thermoplastic film material is cut between the cross-seals to separate a completed package from the sheet of thermoplastic film material.
The present invention also encompasses an apparatus for attaching lengths of reclosable zipper strip to thermoplastic film material. The apparatus comprises a first guide plate and a second guide plate. The first and second guide plates are separated from each other by a guide space and have first and second ends. The first guide plate is longer than the second guide plate so that the first end of the first guide plate is offset from the first end of the second guide plate.
The apparatus also comprises a cutting knife disposed over the guide space adjacent to the first end of the second guide plate. The cutting knife is adapted to cut the reclosable zipper strip being conveyed along the guide space.
The apparatus further comprises a first hole punch and a second hole punch which are across the guide space from each another on the first guide plate and second guide plate, respectively. The first and second hole punches are at a preselected distance along the first and second guide plates from the cutting knife. The first and second hole punches are adapted to remove preselected amounts of the flanges of the reclosable zipper strip.
The apparatus finally includes means for feeding reclosable zipper strip into the guide space, and a seal bar and an anvil which seal the leading flange of the web of one of the male and female interlocking profiles to the sheet of thermoplastic film material.

Method for attaching reclosable zipper strip transversely to a sheet of thermoplastic film material


Aspects of the present invention disclose a method for delivering an artificial intelligence-based response to a voice command to a user. The method includes one or more processors identifying an audio command received by a computing device. The method further includes determining a first engagement level of a user, wherein an engagement level corresponds to an attentiveness level of the user in relation to the computing device based at least in part on indications of activities of the user. The method further includes identifying a first set of conditions within an immediate operating environment of the computing device, wherein the first set of conditions indicate whether to deliver a voice response to the identified audio command. The method further includes determining whether to deliver the voice response to the identified audio command to the user based at least in part on the first engagement level and first set of conditions.

The present invention relates generally to the field of mobile devices, and more particularly to artificial intelligence-based responses of virtual assistants.
In recent years, developments in digital assistants and the growth of Internet of Things (IoT) capable devices have created competition to introduce new voice interfaces (e.g., for smart speakers, virtual assistance hardware/software, etc.). The IoT is a network of physical devices embedded with electronics, software, sensors, and connectivity which enables these devices to connect and exchange data with computer-based systems. Technology is embedded in IoT-enabled devices that allow these devices to communicate, interact, be monitored, and controlled over the Internet.
Natural language processing (NLP) is a branch of artificial intelligence that helps computers understand, interpret, and manipulate human language. Natural language processing encompasses a broad range of tasks that often intertwine in a practical setting. For example, a computer can apply speech recognition and parsing to a voice recording to gain an understanding of what the voice recording is conveying.
Cognitive analytics combines the use of cognitive computing and analytics. Cognitive computing combines artificial intelligence and machine-learning algorithms, in an approach that attempts to reproduce the behavior of the human brain. Analytics is the scientific process of transforming data into insights for making better decisions. Cognitive analytics applies intelligent technologies to bring unstructured data sources within reach of analytics processes for decision making.

Artificial intelligence based response to a user based on engagement level

International Business Machines Corporation