A gel is used as the joining agent to mount a rain sensor to a windscreen of an automobile. The gel used does not harden even in the long term, and air pockets which form inside the gel or on the boundary surfaces with the glass pane or the sensor migrate into the area around the sensor. The rain sensor is attached to a glass pane without special elastic intermediate elements, using the elasticity of the joining agent for tolerance compensation.

WO 96/21568 describes a method for joining a sensor to a glass pane with the aid of a transparent adhesive tape. In this case, a so-called acrylic foam may, for example, be utilized as the join medium. This material rigidly adheres to the glass pane and is very difficult to remove. The mounting of a sensor on a glass pane requires a vacuum and, under certain circumstances, the prior heating of the glass pane in order to obtain a joint without air bubbles. If the sensor emits or receives radiation, it is frequently desired to incorporate an infrared-permeable daylight filter (black appearance). However, a corresponding black coloring of the acrylic foam is not possible. Long-term temperature tests at 100 degrees resulted in yellowing and hardening of the acrylic foam. These aging phenomena have negative effects on the function and the mechanical retention of the sensor. Consequently, the invention is based on a joining medium silicone gel.
The invention aims to disclose a non-hardening, transparent joining medium that can be colored such that it is permeable to infrared radiation and ensures a permanent and superior joining of a sensor to the respective body.
The invention, in principle, consists of utilizing a gel that remains soft. Such a gel is, for example, available on the market under the designation SilGel 612 from Wacker. One preferably utilizes a colorless silicone gel that has a viscosity of approximately 800-1200 mm2/s at 23 degrees C. and a density of approximately 0.96 g/cm3. The index of reaction n025 may have a value of approximately 1.4026 at 25 degrees C. The aforementioned silicone gel is frequently referred to as RTV-2 caoutchouc silicone and is available on the market under the trade name Semicosil 912 from Wacker Chemie GmbH.
The main advantages of this gel can be seen in the fact that it cannot harden, and that it remains a soft, gelatine-like vulcanized material even after a prolonged period of time and after being subjected to heat and insolation for prolonged periods of time. Another important aspect regarding the gel is that it cannot permanently enclose air particles. These air particles are removed from the gel due to their natural movement after a certain period of time. The gel also prevents stress between the housing of the sensor and the glass pane to which the sensor is joined.
One particular advantage of the gel used can be seen in the fact that it can be colored with a dye that is permeable to infrared measuring radiation, with said dye largely acting as a filter for other (light) radiation such that the measuring accuracy of a measuring device (e.g., a rain sensor) that operates with infrared radiation can be increased.
It appears possible to directly join the transmitter and/or receiver (sensor) to the glass pane by means of admixtures to the silicone gel. The present invention also discloses a new method for mounting the sensor on a body, in particular, a windshield, which utilizes the previously described joining medium. In this case, the objective consists of simply pressing the sensor onto the windshield by means of a prestress by utilizing the joining gel. In this respect, it was proposed to elastically join the sensor to the glass pane by means of the gel with the aid of a spring element that is supported on the glass pane, e.g., a spring element that is arranged in the bracket of a rearview mirror which contacts the glass pane. According to the invention, a sensor is particularly suitable for this mounting method. Consequently, the invention, in principle, consists of utilizing a gel of the previously described type as the joining medium for this mounting method, with the transmitter and/or receiver being combined in the form of a transceiver that operates as a rain sensor. The radiation emitted and received by the rain sensor preferably consists of infrared light, with the joining medium being colored with a dye that is permeable to infrared light, in particular, a black dye. Due to this measure, the rain sensor that is usually provided with a dark housing has an entirely black appearance such that the joining medium which is visible through the glass pane cannot be optically differentiated from the rest of the sensor housing.
In order to ensure that the detectors and radiation elements arranged within the sensor and the receiver have exactly the prescribed distance from the glass plane surface, the invention proposes the additional development defined by the projections maintaining an exact distance between the transmitter and/or receiver and the glass pane. In addition, the resulting channels ensure that excess gel is able to escape. Consequently, the gel situated between the sensor surface and the glass pane not only has a predetermined thickness, but the desired density can also be obtained largely independent of the quantity introduced during the mounting process. In this respect, it is possible to apply a slightly larger quantity of the gel than required onto the surface of the sensor which faces the windshield. When the sensor or the sensor housing is subsequently pressed onto the glass pane with its front circumferential edge, the excess gel is able to laterally escape through projections such that the gel is always arranged between the sensor and the glass pane with the same stress and the same density. In order to preserve the density and the stress in the joining medium (gel), the invention proposes the additional development in which as mentioned previously, it was proposed to generate prestress by means of additional springs that are supported on the glass pane. This particular variation can be simplified by utilizing an additional development of the invention which is defined by the combination of characteristics proposes that a holder which acts upon the sensor in a largely rigid fashion is mounted on the glass pane. In this case, the elastic effect is not achieved by means of an additional spring, but rather by the spring effect of the joining medium (gel). Due to this measure, a largely uncomplicated construction for the holder is achieved. In thus case, the wall of the holder is initially connected to the glass pane during the mounting process, whereafter the sensor with its housing and the applied joining medium is inserted into the wall of the holder. Subsequently, the cover is connected to the wall of the holder by exerting a force in the direction of the glass pane. However, other constructions would also be conceivable. For example, the sensor housing can be directly locked in the wall of the holder, or the holder with the inserted sensor (and joining medium) can be mounted (bonded) to the glass pane by exerting a pressing force.
The shape of the wall of the holder is adapted to the outer contour of the sensor. This wall has a particularly simple design if the sensor has an essentially circular shape, i.e., the wall has an annular appearance.
The function of the holder does not necessarily have to consist of providing a support for the sensor relative to the glass pane. The holder may also accommodate electric connections, e.g., in the form of a multiple plug. These electric connections make it possible to connect the sensor to the corresponding electric units during the mounting process. The power supply may also be realized via the electric connections of the holder.
The holder may, in principle, be simply bonded to the glass pane by means of adhesive agents. However, it would also be conceivable to lock the holder on the glass pane by means of locking elements that are cast into the glass pane. A particularly simple arrangement for the holder is proposed in a combination of characteristics in which the holder is shaped out of the glass pane material or cast into the glass pane. For example, a holder that consists of metal or plastic is cast into the glass pane during its manufacture. However, the glass pane material can also be directly shaped into a holder. Accordingly, connecting lines which lead to the holder are not bonded onto the glass pane in this case, but directly cast into the glass pane.
If the quantity of the joining medium situated between the sensor and the glass pane is precisely metered, the sensor can be arranged at a prescribed distance from the glass pane and the joining medium can be provided with the desired density between the sensor and the glass pane, e.g., if the holder and the sensor are subject to strict tolerances. However, in order to allow an additional tolerance, the invention proposes an additional development in which the projections do not necessarily have to contact the glass pane in order to exactly maintain the corresponding distance. It suffices if the projections form channels, through which the excess joining medium can be laterally pressed out due to a predetermined force, i.e., the gel subsequently has a predetermined thickness. The width of the channels consequently influences the stress to which the gel is subjected in the joined state.
The snap-in connection between the holder and the sensor in accordance with the invention can also be utilized for separating this connection if a permissible lateral force is exceeded. In this case, the sensor is freely movable relative to the glass pane such that the risk of injuries due to a projecting sensor is eliminated during an accident

Sensor joined to a glass pane with a silicon gel

Valeo Auto-Electric Wischer und Motoren GmbH


An imitation gem consisting of a semi shell of a transparent plastic material with concave inner and convex outer surfaces has light reflecting and light refracting facets formed on both its inner concave and outer convex surfaces. The open end of the semi shell is closed by a cover which is also provided with facets so as to further improve light reflection and refraction.

The invention relates to fashion jewelry, especially to an imitation gem having light refracting and ligh reflecting faceted surfaces.
Such imitation gems, developed by imitation of chandelier glasses, were formerly made of glass and recently of transparent plastic materials. Chandelier glasses have iridescent coatings which are made, for example, by applying to the glass silver sulfuric resinate in solution with certain additives and then baking the glass. The iridescent coatings so produced are semitransparent mirrors which increase the effects of light reflection and refraction on the surfaces of the glasses at the interface of glass and air.
In order to obtain as many iridescent surfaces as possible, a chandelier consists of glass sections arranged at a multitude of angles relative to one another similar to the surface cut of a diamond. In the manufacture of imitation gems, it has been attempted to imitate these geometric shapes, that is, it has been tried to provide the gems with many surfaces arranged at angles relative to one another so as to provide for certain reflection characteristics. It has been found, however, that such reflection alone cannot generate the effects of iridescence of the original chandelier glasses.
In imitation gems which have one particular display side, the reflection capabilities have been improved by applying light reflecting metal coatings to the back surfaces which are also disposed at various angles.
It is the principal object of the present invention to provide an imitation gem which reflects the light to a large degree in highly concentrated rays but also in refracted form.
High reflection and refraction of light rays on an imitation gem are obtained by forming the gem of a transparent semi shell with a cover mounted thereon and with facets formed on the concave inner and convex outer surfaces of the shell and on the cover.
Such a gem body has faceted surface areas not only on the outside as it has been known but it also has inner surface areas with facets formed thereon. It may consist of two identical half shells, each of which is faceted on its outer and on its inner surfaces. This results in a large number of facets which all are exposed to air, causing reflection of the light at all interfaces of the transparent body and air that is at the outer as well as inner surfaces of the shell. The large number of facets provides for a large number of mirror surfaces which reflect the light at their interface with air and which refract the light rays which pass through the shell walls. As a result, the imitation gem according to the invention appears quite sparkling. This effect can be even further pronounced if the inner surfaces of the exposed side of the shell are provided with a light reflecting metal coating. If the metal coating is made to be so thin that it is semitransparent for light, light rays will pass through the metal coating into the interior of the imitation gem. If then the inner surface of the other semi shell is also provided with facets and with a reflective metal coating which is preferably also semitransparent, the imitation gem will reflect, refract and pass light rays entering from the front but also from the back side. Such imitation gems may be used in the manufacture of sparkling fashion jewelry, especially highly attractive sparkling earrings and other pendants can be created.
Preferably, the facets on the inner concave and the outer convex surfaces of the semi shell are similar but the semi shells are angularly displaced with respect to one another by half the width of the facets so as to provide an even larger number of prismatic light refracting surfaces which are disposed at an angle to one another.
However, the inner and outer facets may be displaced relative to one another by less than half their diameter, for example, by one fourth of their diameter.
If it is desired to obtain a certain orientation of the reflected light, the curvature of the shells may be selected to be aspherical or otherwise shaped as desired. For economical manufacture, however, it is preferable if both semi shells are identical in shape and consist of transparent plastic material.
In place of interconnecting two semispherical shells, it is possible to mount a backplate on a semi shell which backplate is also preferably provided with facets. Such an arrangement is especially advantageous if the imitation gem is intended for use in clothing jewelry but it may also be used for earrings or pendants if the gem is to be relatively flat. A gem formed in this manner also has the effects of iridescence described earlier mainly, however, generated by the facets of the curved semi shell on which the backplate is mounted.


High-span and high-strength anchors and reinforcement devices for cavity walls combined with interlocking veneer ties are described which utilize reinforcing wire and wire formatives to form facing anchors, truss or ladder reinforcements, and wall anchors providing wire-to-wire connections therebetween. These combine wire formatives which are selectively and compressively reduced in height by cold-working. The masonry anchor have eye wires accommodating the threading thereinto of a wire facing anchor or wall tie with either a pintle inserted through the eye or the open end of the wall tie. The wall tie is then positioned so that the insertion end is embedded in the facing wall. The masonry anchor is embedded in a bed joint of the interior wythe. For high-strength applications, specific wire formatives are used which employ materials that benefit from the cold-working of the metal alloys to meet the unusual requirements demanded.

1. Field of the Invention
This invention relates to improved anchors and reinforcements for masonry backup walls that serve cavity wall constructs with larger-than-normal cavities between the masonry backup wall and the facing brick veneer. More particularly, the invention relates to cavity walls requiring novel anchoring systems for spanning such cavities and, further to the use of resistance-welded, wire formatives to meet existing wind shear and seismic specifications.
2. Description of the Prior Act
Recently, there have been significant shifts in public sector building specifications which have resulted in architects and architectural engineers requiring larger and larger cavities in the exterior cavity walls of public buildings. These requirements are imposed without corresponding decreases in wind shear and seismic resistance levels or increases in mortar bed joint height. Thus, wall anchors are needed to occupy the same xe2x85x9c-inch-high space in the inner wythe and tie down a veneer facing material of an outer wythe at a span of two or more times that which had previously been experienced.
Exemplary of the public sector building specification is that of the Energy Code Requirement, Boston, Mass. (see Chapter 13 of 780 CMR, Seventh Edition). This Code sets forth insulation R-values well in excess of prior editions and evokes an engineering response opting for thicker insulation and correspondingly larger cavities. Here, the emphasis is upon creating a building envelope that is designed and constructed with a continuous air barrier to control air leakage into or out of conditioned space adjacent the inner wythe.
Another application for high-span anchoring systems is in the evolving technology of self-cooling buildings. Here, the cavity wall serves additionally as a plenum for delivering air from one area to another. While this technology has not seen wide application in the United States, the ability to size cavities to match air moving requirements for naturally ventilated buildings enables the architectural engineer to now consider cavity walls when designing structures in this environmentally favorable form.
In the past, the use of wire formatives have been limited by the mortar layer thicknesses which, in turn are dictated either by the new building specifications or by pre-existing conditions, e.g. matching during renovations or additions the existing mortar layer thickness. While arguments have been made for increasing the number of the fine-wire anchors per unit area of the facing layer, architects and architectural engineers have favored wire formative anchors of sturdier wire. On the other hand, contractors find that heavy wire anchors, with diameters approaching the mortar layer height specification, frequently result in misalignment. Thus, these contractors look towards substituting thinner gage wire formatives which result in easier alignment of courses of block.
In the past, there have been investigations relating to the effects of various forces, particularly lateral forces, upon brick veneer construction having wire formative anchors embedded in the mortar joint of anchored veneer walls. The seismic aspect of these investigations were referenced in the first-named inventor""s prior patents, namely, U.S. Pat. Nos. 4,875,319 and 5,408,798. Besides earthquake protection, the failure of several high-rise buildings to withstand wind and other lateral forces has resulted in the incorporation of a requirement for continuous wire reinforcement in the Uniform Building Code provisions. The first-named inventor""s related SeismiclipR and DW-10-XR products (manufactured by Hohmann and Barnard, Inc., Hauppauge, N.Y. 11788) have become widely accepted in the industry. The use of a wire formative anchors and reinforcement wire structures in masonry walls has been shown to protective against problems arising from thermal expansion and contraction. Also, such structures have improved the uniformity of the distribution of lateral forces. However, these past investigations do not address the mortar layer thickness vs. the wire diameter of the wire formative or the technical problems arising therefrom.
Over time and as the industry matured, besides the Uniform Building Code other standards came into existence, including the promulgation by the ASTM Committee A01 on Steel of the Standard Specifications for Masonry Joint Reinforcement, A951-00 (hereinafter A951). The Standard sets forth that masonry joint reinforcement is to be assembled by automatic machines to assure accurate spacing and alignment of all members of the finished product and that longitudinal and cross wires are to be securely connected at every intersection by an electric-resistance welding process that includes fusion welding together with applied pressure to join the materials. The Standard further sets forth details as to the exterior of the longitudinal wires and the mechanical requirements of the overall construct.
According to the ASTM Committee A01, joint reinforcement has been used in the masonry industry since 1940. In introducing A951, the Committee states:
For most of the period since then, its manufacture has been limited to a relatively small group of producers and users who simply referred to xe2x80x9cmanufacturers"" recommendationsxe2x80x9d as the standard of quality and acceptance. With the adoption of a new consensus standard for the design of masonry, it became clear that a standard for the manufacture of joint reinforcement was needed. In developing this standard it was decided to use a format similar to that used for the ASTM Standard for Welded Wire Fabric, Plain, for Concrete Reinforcement, Specification A185, since many people had the notion that joint reinforcement was used in a manner similar to wire mesh. A significant difference between wire mesh and joint reinforcement arose when an attempt was made to fashion the requirements for weld shear strength after those in Specification A185.
The Committee found that almost all of the manufacturers of joint reinforcement use butt welds so that the total thickness of material at a weld is as small as possible. This is important since, in conventional mortar bed joints, there is not much room to install joint reinforcement. In addition, it found that in masonry joint reinforcement the majority of product produced is that with a xe2x80x9ctrussxe2x80x9d configuration in which the angle of intersection varies for each different width of product produced since the pitch between welds is a constant 16 inches. These characteristics differentiated the testing for weld shear strength from those of Specification A185 and resulted in the development of a distinct test methodology.
In the course of preparing this disclosure several patents became known to the inventors hereof. The following patents are believed to be relevant and are discussed further as to the significance thereof:
It is noted that with some exceptions these devices are generally descriptive of wire-to-wire anchors and wall ties and have various cooperative functional relationships with straight wire runs embedded in the inner and/or outer wythe.
U.S. Pat. No. 3,377,764xe2x80x94D. Storchxe2x80x94Issued Apr. 16, 1968
Discloses a bent wire, tie-type anchor for embedment in a facing exterior wythe engaging with a loop attached to a straight wire run in a backup interior wythe.
U.S. Pat. No. 4,021,990xe2x80x94B. J. Schwalbergxe2x80x94Issued May 10, 1977
Discloses a dry wall construction system for anchoring a facing veneer to wallboard/metal stud construction with a pronged sheetmetal anchor. Like Storch ""764, the wall tie is embedded in the exterior wythe and is not attached to a straight wire run.
U.S. Pat. No. 4,373,314xe2x80x94J. A. Allanxe2x80x94Issued Feb. 15, 1983
Discloses a vertical angle iron with one leg adapted for attachment to a stud; and the other having elongated slots to accommodate wall ties. Insulation is applied between projecting vertical legs of adjacent angle irons with slots being spaced away from the stud to avoid the insulation.
U.S. Pat. No. 4,473,984xe2x80x94Lopezxe2x80x94Issued Oct. 2, 1984
Discloses a curtain-wall masonry anchor system wherein a wall tie is attached to the inner wythe by a self-tapping screw to a metal stud and to the outer wythe by embedment in a corresponding bed joint. The stud is applied through a hole cut into the insulation.
U.S. Pat. No. 4,869,038xe2x80x94M. J. Catanixe2x80x94Issued Sep. 26, 1989
Discloses a veneer wall anchor system having in the interior wythe a truss-type anchor, similar to Hala et al. ""226, supra, but with horizontal sheetmetal extensions. The extensions are interlocked with bent wire pintle-type wall ties that are embedded within the exterior wythe.
U.S. Pat. No. 4,879,319xe2x80x94R. Hohmannxe2x80x94Issued Oct. 24, 1989
Discloses a seismic construction system for anchoring a facing veneer to wallboard/metal stud construction with a pronged sheet-metal anchor. Wall tie is distinguished over that of Schwalberg ""990 and is clipped onto a straight wire run.
U.S. Pat. No. 5,392,581xe2x80x94Hatzinikolas et al.xe2x80x94Issued Feb. 28, 1995
Discloses a cavity-wall anchor having a conventional tie wire for mounting in the brick veneer and an L-shaped sheetmetal bracket for mounting vertically between side-by-side blocks and horizontally on atop a course of blocks. The bracket has a slit which is vertically disposed and protrudes into the cavity. The slit provides for a vertically adjustable anchor.
U.S. Pat. No. 5,408,798xe2x80x94Hohmannxe2x80x94Issued Apr. 25, 1995
Discloses a seismic construction system for a cavity wall having a masonry anchor, a wall tie, and a facing anchor. Sealed eye wires extend into the cavity and wire wall ties are threaded therethrough with the open ends thereof embedded with a Hohmann ""319 (see supra) clip in the mortar layer of the brick veneer.
U.S. Pat. No. 5,456,052xe2x80x94Anderson et al.xe2x80x94Issued Oct. 10, 1995
Discloses a two-part masonry brick tie, the first part being designed to be installed in the inner wythe and then, later when the brick veneer is erected to be interconnected by the second part. Both parts are constructed from sheetmetal and are arranged on substantially the same horizontal plane.
U.S. Pat. No. 5,816,008xe2x80x94Hohmannxe2x80x94Issued Oct. 15, 1998
Discloses a brick veneer anchor primarily for use with a cavity wall with a drywall inner wythe. The device combines an L-shaped plate for mounting on the metal stud of the drywall and extending into the cavity with a T-head bent stay. After interengagement with the L-shaped plate the free end of the bent stay is embedded in the corresponding bed joint of the veneer.
U.S. Pat. No. 6,209,281xe2x80x94Ricexe2x80x94Issued Apr. 3, 2001
Discloses a masonry anchor having a conventional tie wire for mounting in the brick veneer and sheetmetal bracket for mounting on the metal-stud-supported drywall. The bracket has a slit which is vertically disposed when the bracket is mounted on the metal stud and, in application, protrudes through the drywall into the cavity. The slit provides for a vertically adjustable anchor.
U.S. Pat. No. 6,279,283xe2x80x94Hohmann et al.xe2x80x94Issued Aug. 28, 2001
Discloses a low-profile wall tie primarily for use in renovation construction where in order to match existing mortar height in the facing wythe a compressed wall tie is embedded in the bed joint of the brick veneer.
None of the above provide the high-span anchors and reinforcements for the masonry backup walls as applied to structures having larger-than-normal cavities. In the above-cited related Application, wire formatives are compressively reduced in height at the junctures between the wall reinforcements and the wall anchors. This enabled the stacked components to be inserted within the bed joints and still have a covering of mortar. While this approach worked well, alternatives utilizing electric resistance welding techniques are presented hereinbelow.
In general terms, the invention disclosed hereby includes a high-span anchor and reinforcement device for a cavity wall combined with an interlocking veneer tie. The wall construct has an inner wythe or backup wall and an outer wythe or facing wall. The wythes are in a spaced apart relationship and form a larger-than-normal cavity therebetween. In the embodiments disclosed, a unique combination of a wall anchor, a reinforcement and a veneer tie is provided. The invention contemplates that the primary components of the system are structured from reinforcing wire and wire formatives, such as truss reinforcement or ladder mesh reinforcements, and provide wire-to-wire connections therebetween. Further, the various embodiments combine wire formatives which are selectively and compressively reduced in height by the cold-working thereof.
The embodiments of the invention disclosed hereby include high-span anchors incorporating a low-profile veneer tie for use in the construction of a wall having an inner wythe with thick strips of insulation attached thereto. Because of compressive reduction in height of extended leg portions that span the insulation, the air leakage at and adjacent heavy wire components is substantially overcome. This results as the strips of insulation are installed so that the seams between the strips are coplanar with the inner wythe bed joints. The compressively reduced in height wall anchors protrude into the cavity through the seams, which seams seal thereabout so as to maintain the integrity of the insulation and minimize air leakage along the wall anchors. The invention contemplates that some components of the system are as described in U.S. Pat. Nos. 5,408,798; 5,454,200; and 6,279,283 and that the wire formatives hereof provide a positive interlocking connection therebetween specific for the requirements created by this high-span application.
In the mode of practicing the invention, wherein the inner wythe is constructed from a masonry block material, the masonry anchor has, for example, a truss portion with eye wire extensions welded thereto. The eye wires extend across the insulation into the cavity between the wythes. Each of the eye wires accommodates the threading thereinto of a wire facing anchor or wall tie with either a pintle inserted through the eye or the open end of the wall tie. The wall tie is then positioned so that the insertion end is embedded in the facing wall. The masonry anchor is embedded in a bed joint of the interior wythe. Wall and veneer ties compressively reduced in height are described as being mounted in bed joints of the inner and outer wythes. The close control of overall heights permits the mortar of the bed joints to flow over and about the wall reinforcement and wall tie combination inserted in the inner wythe and insertion end of the wall in the outer wythe. As the test data shown below confirms, the use of the specific wire formatives hereof, which employ extra strong material and benefit from the cold-working of the metal alloys, the high-span reinforcement and wall anchor devices meet the unusual requirements demanded.
It is an object of the present invention to provide, for cavity walls with a larger-than-normal cavities, anchoring systems and anchors for the masonry backup walls thereof and provide for the securement of facing veneers.
It is another object of the present invention to provide labor-saving, high-span anchoring systems which employ resistance welded, wire formatives in the mortar joint of the inner wythe and is adapted to be positively interconnected with a veneer tie inserted into the outer wythe.
It is yet another object of the present invention to provide a high-strength, anchoring systems for heavily insulated cavity wall structures which utilizes high cross-sectional area components for wall reinforcement of the inner wythe in a manner such that the mortar layer coverage thereof is maintainable.
It is a further object of the present invention to provide a high-span anchoring systems comprising a limited number of component parts that are economical of manufacture resulting in a low unit cost.
It is yet another object of the present invention to provide a high-span anchoring systems which are easy to install and which meet seismic and shear resistance requirements.
It is a feature of the present invention that the portion of the wall anchor embedded in the bed joint of the inner wythe is fused during resistance welding thereof to the wire reinforcement portion.
It is another feature of the present invention that the veneer anchor, the wall tie and the combined wall anchor and wall reinforcement are dimensioned so that, when inserted into the respective mortar layers, the mortar thereof can flow around the wall-tie-to-reinforcement-wire joint.
It is yet another feature of the present invention that the reinforcement wire of the inner wythe is combinable with a low-profile wall anchor to span the insulation of the cavity wall at the seam thereof and that the wall tie is sealingly surrounded by the insulation.

High-span anchors and reinforcements for masonry walls


A baggage slide attached to a movable elevated passenger walkway/bridge.

1. Field of the Invention
The present invention relates generally to baggage handling, and more specifically to an inclined baggage slide coupled to an elevated aircraft passenger bridge.
2. Description of Related Art
The use of a baggage slide outside the service door of the passenger loading bridge is to transfer baggage to the cargo loading area from the elevation and area directly adjacent to the passenger entrance to the aircraft.
Owing to a growing trend among air travelers to carry their baggage onboard instead of checking it through at the ticket counter, overhead storage locations on aircraft can become dangerously overburdened. The FAA has guidelines restricting the size and number of pieces of carry-on luggage allowed, which the agency is urging the airlines to enforce. This baggage slide allows flight attendants and ground crews to swiftly and accurately handle overflow baggage without causing aircraft to sustain ground delays.
In addition, in many situations disabled persons are not required to give advance notice to the airlines of their special needs, and frequently arrive for boarding at the passenger loading bridge in wheelchairs. The wheelchairs must be quickly checked as cargo after the disabled person has boarded the aircraft. Hence, there is a need for a baggage slide capable of quickly and efficiently delivering baggage and other cargo, such as wheelchairs, to the cargo loading area. The present invention satisfies this need.
U.S. Pat. No. 6,109,854 to Thompson, Jr. et al. discloses a ramp in an attempt to solve the above described problems. However, this baggage slide has several inherent deficiencies which limit its use due to its structure and method of attachment. Specifically, the Thompson slide has several limitations that limit its ability to accommodate the height the bridge has to be elevated to in turn accommodate the bridge connection to the aircraft access door. Thompson discloses a ramp which has an inclined portion starting at the tarmac at its lower end and terminating at the upper level first stair. The ramp is fixed to the employee auxiliary access stairway at at least two locations, one being at the top of the riser of the first step and the other being at the leading edge area of the stairway upper level platform.
From a safety standpoint, this creates shear loading and stress on the stairway assembly which could cause an accident whereby the ramp and stairway assembly separate from the bridge frame and fall to the ground.
In addition, where the Thompson device is connected to the stairway upper level platform at at least two points, the pivot point for the inclined portion is by necessity located near the top of the first step riser. Should a Boeing 757 or 777 then be parked at the terminal gate, the bridge may have to be elevated. In such a case, the ramp inclination angle changes rapidly and the angle is found to be too steep. That is the formed hypotenuse of the inclined portion of the ramp is relatively short in comparison to the present invention and any elevation change quickly affects the steepness of the incline.
The present invention overcomes this deficiency because, as described in more detail below, the attachment is independent of the stairway assembly and the ramp instead attaches directly to the framework of the bridge assembly. No additional load is applied to the stairway as a result of the ramp weight itself or in combination with the weight of objects sliding down the ramp. Further, the attachment point which is also the pivotal point is near an underneath surface of the stairway landing platform but at its leading edge closest to the aircraft, thereby resulting in a longer inclined portion or formed hypotenuse. Now when the bridge needs to the elevated, the longer inclined ramp can be elevated without dramatically changing the slope of the incline.
In addition, because the present invention is a continuously inclining ramp, as opposed to the flat upper level fixed platform of the Thompson reference, the first upper level segment of the present invention ramp continues its incline. This provides a further ergonomic benefit to baggage handlers as the upper end of the incline is at a higher elevation such that a baggage handler need not bend down as far to place an article onto the ramp. The upper end of the incline is in effect closer to a height between the waist and knees of a typical handler.
The present invention is a baggage slide for a movable elevated passenger walkway/bridge having attached to said movable elevated passenger walkway/bridge an auxiliary access stairway extending downwardly on an incline from the movable elevated passenger walkway/bridge to the tarmac. The auxiliary access stairway has an upper portion landing platform for facilitating access for airline service employees to and from the elevated passenger walkway/bridge from and to the tarmac.
More specifically, the inventive baggage slide comprises a baggage slide support member attached to a movable elevated passenger walkway/bridge and extends from said elevated passenger walkway/bridge near a leading edge and near an underneath side of an auxiliary access stairway""s upper portion landing platform. The baggage slide support member further laterally extends beyond the auxiliary access stairway""s upper portion landing platform a sufficient length to pivotally couple a loading end of an inclined modular ramp assembly.
The inclined modular ramp assembly includes an unloading end for resting on a tarmac surface with a generally planar conveyance surface extending between the unloading end and the loading end for the sliding conveyance of an article from the loading end to the unloading end. The inclined modular ramp assembly is disposed near and generally parallel to the auxiliary access stairway.
The inclined modular ramp assembly further includes upstanding wall members generally along each edge of the generally planar conveyance surface. The upstanding wall members are means for preventing the sliding article from falling off the generally planar conveyance surface.
The loading end of the inclined modular ramp assembly preferably has side access means for loading the article from the auxiliary access stairway""s upper portion landing platform onto the inclined modular ramp assembly, while the unloading end of the inclined modular ramp assembly has side access means for removing the article from the inclined modular ramp assembly.
In a typical application of the invention, the unloading end of the inclined modular ramp assembly further comprises an article stop extending substantially across the inclined modular ramp assembly with the article stop further being located downstream of the side access means for removing the article from the inclined modular ramp assembly. The article stop is adapted to absorb the impact shock of the sliding article. For example, the article stop typically may be a rubber reinforced gate.
The inclined modular ramp assembly typically comprises a loading segment, an unloading segment and at least one intermediate segment there between.
The generally planar conveyance surface comprises a longitudinally oriented channel corrugated surface defining rain water runoff paths between upper surfaces of the channel corrugated surface.
The side access means for loading the article from the auxiliary access stairway""s upper portion landing platform onto the inclined modular ramp assembly includes a first segment for funneling the article to said loading end. The first segment has a width gregreater than a corresponding width of the unloading end.
In an additional embodiment of the invention, the inclined modular ramp assembly further includes a shell for covering at least a portion of the inclined modular ramp assembly.
In another embodiment of the invention, the inclined modular ramp assembly comprises one or more segments of predetermined length each, wherein each segment is adjustable in length so as to maintain a substantially constant ratio between a height of the loading end from the tarmac surface and a length of the inclined modular ramp assembly.
Of course, the inclined modular ramp assembly may comprise a loading segment, an unloading segment and a plurality of intermediate segments there between, where the plurality of intermediate segments have at least two different lengths.
For facilitating relative movement along the tarmac as the bridge is elevated somewhat to adjust to specific aircraft configurations, the unloading end preferably has ground engagement wheels coupled to the inclined modular ramp assembly at said unloading end.
For items that need to be lowered carefully or for items htat need to be elevated from the tarmac to the aircraft, winch means located at the loading end for the controllable lowering of the article down the inclined modular ramp assembly and for the transfer of the article up the inclined modular ramp assembly, may be incorporated.
For weather protection, the inclined modular ramp assembly may include a shell for covering a substantial portion of the inclined modular ramp assembly.
The longitudinally oriented channel corrugated surface also provides for a reduced friction thereby enhancing the sliding of the article down the inclined modular ramp by causing only the upper surface of the longitudinally oriented channel corrugated surface to be in direct contact with the article as the article slides down the inclined modular ramp.
The loading segment typically comprises a platform portion and a connecting portion for connecting the platform portion to the at least one intermediate segment, wherein the platform portion and the connecting portion form an obtuse angle. Similarly, in the embodiment with the plurality of intermediate segments, the loading segment comprises a platform portion and a connecting portion for connecting the platform portion to the plurality of intermediate segments, wherein the platform portion and the connecting portion form an obtuse angle.
Related objects and advantages of the present invention will be apparent from the following description.


Compositions are disclosed for the flame retardation of polymeric compositions including fillers such as glass fibers. The compositions contain a flame retarding effective additive of at least one polyphosphate, a sulfur containing compound, catalyst and a nitrogen containing compound such as melamine.

The present invention relates to the flame retardation of polymeric compositions and especially compositions including fillers such as glass fibers, and, contrary to prior art teachings,without the use of red phosphorus and of halogen-based additives. This application correspond to Disclosure Document 457665 of Jun. 14, 1999.
Flame retardation of polymers is at present mandatory for many of their application in many countries due to strict laws and regulations. Of particular importance are the requirements of polymeric devices, used in electrical, electronic and communication systems, which in many cases contain sizable amounts of glass fibers and other fillers. Accordingly, a number of systems for flame retarding various polymers were developed. These flame-retarding systems usually involve mixing or blending of the plastics with one or more flame retarding chemical additives. Most of these chemicals are either based on halogens or on red phosphorus and constitute low molecular weight compounds. They are in many cases applied in conjunction with co-additives or synergists such as antimony trioxide in the case of halogen compounds. The halogen-based additives provide a reasonable protection from fire hazards, however, they suffer from a number of serious inadequacies, which are responsible for difficulties in their application and use; they generate upon combustion highly-corrosive hydrogen halides and toxic substances. Red phosphorus which is used for glass-fiber containing polyamides can cause the emission of the undesirable toxic phosphine gas.
An important development in flame retardancy employed the principle of intumescence. According to this principle, the flame retardant additives form during the first stages of pyrolysis and combustion a foamed porous barrier which is impermeable to the combustible gases evolved during pyrolysis and to the molten polymer and prevents their flow to the flaming surface. In addition, it is believed that the intumescent barrier hinders the convection of the heat generated in the combustion from entering into the plastic. The additives used in the intumescent systems comprise a xe2x80x9ccatalystxe2x80x9d, usually ammonium polyphosphate (APP), a char-forming agent, in most cases a polyhydric alcohol such as pentaerythritol and a blowing agent usually a nitrogeneous material, such as melamine, guanidine or urea, which produce non-combustible gases. The APP is assumed to serve as a dehydration catalyst of the polyhydric alcohol and the dehydration is believed to occur via phosphorylation of the hydroxyl groups of the alcohol as well as of the hydroxyl groups formed by oxidation of the methyl groups of the polymer during combustion. Subsequent thermal dephosphorylation produced double bonds and crosslinks, which led to char structure foamed by the evolving gases from the blowing agent.
Whereas the intumescent systems provided a reasonable degree of flame retardance for a number of polymers such as polyethylene and polypropylene, it could not advantageously be applied to compositions containing glass fibers or other fillers. The presence of the glass fibers prevented the formation of the impermeable barrier essential for effective flame retardance. The char-forming additives appear not to be compatible with filler materials.
It is a primary object of the invention to improve on existing flame retardation techniques of polymeric composition.
It has surprisingly been found, that a high degree of flame retardancy can be imparted to glass fiber-containing polymers by using APP without char-forming agents, but with relatively small amounts of metal-based catalysts and of sulfur compounds. These formulations are very effective. It has unexpectedly and surprisingly been found, and this is the most striking feature of this invention, that the addition to an ammonium polyphosphate-based formulation of a relatively small amount of certain sulfur derivatives brings about a dramatic enhancement of the flame retardant effectivity of the system. The additives, according to the present invention, are less toxic and less corrosive than the formulations used in the art of flame retarding of polymers today. They are also readily available and relatively inexpensive.
The invention is applicable to a considerable number of thermoplastic polymers, including, as examples, polyamide (PA) 6 and 66, PA 11, PA 12, PA 4.4, PA 6.3, PA 6.4, PA 6.10, PA 6.12; polybutylene terephtalate (PBT); Polyethylene terephtalate (PET) and other polyesters saturated and unsaturated; polystyrenics; polyacrylics; polyurethanes; polycarbonates polyethylene (PE); Polypropylene (PP) and blends and copolymers of the above, as well as epoxy resins.
The function of the sulfur derivatives in their surprising effect is not exactly understood. It is believed that the effect is based on a specific new quasi-intumescent effect, which produces upon pyrolysis and combustion a non-dripping and non-ignitable surface with a relatively small amount of char. The sulfur derivative appears to be a more effective catalyst for the dehydration, cross-linking and char formation than APP alone. The sulfation and desulfation occur more rapidly than the phosphorylation and dephosphorylation. The char is formed both by the sulfation and the phosphorylation routes, but the char obtained appears to be a more effective, more compact and less penetrable surface barrier. The sulfur compounds may act as synergists of the APP, similar to the effect of antimony trioxide in the case of halogen-based additives.
The sulfur compounds applicable in the present invention are numerous and diversified. The common feature of all sulfur-based materials of this invention is their ability to interact at the pyrolysis and ignition temperatures, i.e., 350-500xc2x0 C., with the other ingredients of the system i.e. the polymer, APP, glass fibers, and others. They should be stable enough at the processing temperatures, so as not to degrade markedly the polymer, but should react and produce the desirable effect of flame retardancy during combustion. Since the reactivity of various polymers at the high combustion temperatures differs, it is necessary to adapt to given polymeric substrates suitable sulfur derivatives.
The sulfur derivatives used in the present invention include inorganic and organic compounds of several valencies, such as: xe2x88x922; 0; +4; +6. The minus two valency compounds are predominantly metallic sulfides, particularly of low water solubility and difficult to hydrolyze and in particular of heavy metals such as: ZnS1, GeS2, MoS2, MnS, Sb2S3, Sb2S5, and other heavy metal sulfides as described, for example, in Fritz Ephraim Inorganic Chemistry, fourth edition, page 229. Although many heavy metal sulfides may be objectionable for use as additives, in several cases due to toxicity (e.g. lead sulfide), and in other cases due to their dark color (Cu, Mo, Ni, Co, Ag), they could advantageously be used in the present invention. Of particular importance is ZnS due to its white color, high temperature stability, low cost and the fact that it is being used as a pigment additive to plastics to impart a white color. ZnS is thus known to be compatible with polymers. It has surprisingly been found that already small amounts of ZnS, in the range of 1-3 weight % of a polymer composition, yield a pronounced flame retardancy effect. At the combustion temperature, in the presence of air, the zinc sulfide is oxidized to higher valency products such as sulfur, zinc sulfoxylate, ZnSO2, thiosulfates, sulfites and finally sulfates. These oxidation reactions, which usually do not produce hydrogen sulfide, are rapid at the ignition temperature, but the oxidation products, which are more reactive than the sulfide, interact with the polymer and the other ingredients of the plastic composition to render the flame-retarding surface barrier.
It has surprisingly been ascertained that when applying sulfur compounds of the valencies between 6 and xe2x88x922, high degrees of flame retardancy can also be obtained. The present invention thus encompasses such compounds as elementary sulfur, sulfites and thiosulfates and mixtures of these materials themselves or with sulfides. The reactivity of these materials which are considered as steps in the oxidation of sulfides is naturally higher than of the stable sulfides. Undesirable effects such as degradation, and unpleasant odors may thus occur, depending on the polymer and on the condition of the processing. It is evident however, that for those skilled in the art, appropriate conditions for the application of these compounds to suitable polymers, will be readily chosen.
U.S. Pat. No. 5,424,344 describes the use of oxygenated hexavalent sulphur derivatives, together with char-forming agents, for flame retarding polyamides. Whereas good flame retardancy is obtained with the formulation in that patent, relatively large quantities of additives are needed for this effect especially in glass fiber-containing polyamides. In addition, the mechanical properties are impaired. The same oxygenated hexavalent sulfur derivatives can also be used in the present invention, but together with APP. These oxygenated hexavalent sulfur derivatives for the purposes of this invention can include inorganic and organic derivatives of sulfuric and sulfamic acids. Among these materials are ammonium and metal salts of sulfamic acid, condensation products of sulfamic acid, such as imidobisulfonic acid, NH(SO3H)2, and their salts, such as mono- and diammonium salts, alkali metal and alkaline earth salts, and other divalent and multivalent salts. The hydrogen atoms in the sulfamates can also be substituted by aliphatic, aromatic and cyclic derivatives. The invention also includes sulfamide, NH2SO2NH2NH(NH2SO2)2 and aliphatic and aromatic substituents of sulfamide, R1R2NSO2NR3R1. The substituents in all the above cases can be different aromatic and aliphatic groups, which can be advantageously C1-6-alkyl, phenyl or naphtyl, each optionally substituted by any halogen-free moiety. The invention also includes cyclic sulfamides and sulfimides.
The amounts of the sulfur-containing additive (a) to be used in the present invention depend on the polymer and the amount of the glass fibers or other fillers, as well as on the nature of the sulfur compound applied, and varies from 0.01% to 15.0%. When using ammonium sulfamate a different quantity is needed than, for example, in the cases of elementary sulfur, sodium sulfite or zinc sulfide.
The amounts of APP-additive (b) needed according to the invention may vary between 10 to 40 weight % of the overall composition, depending on the other ingredients present and especially on the amount of the glass fibers or other fillers added.
As will be seen in the examples below a certain degree of flame retardancy is obtained according to the present invention with APP also without the sulfur derivative, and especially in the presence of additional materials, such as metal-based catalytic compounds. The amount of APP needed for a significant effect is not significantly different from the amount used in the presence of the sulfur derivatives. The flame retardant effect of the APP with the catalyst expresses itself in an increase in the oxygen index (OI) and in the absence of flaming drips, but the rating according to the UL94 standard is low.
Ammonium polyphosphate is not the only salt of polyphosphoric acid which can be used in this invention. A part of the APP can be replaced by melamine polyphosphate, the amount depending upon the polymer processed and the sulfur derivative used. APP can also be partly replaced by melamine and its condensation products, such as melam and melem and to a small extent, also by the catalyst.
Another important feature of the present invention is the addition of metal-based catalysts (C). These compounds comprise oxides and salts of alkali, alkaline earth, divalent and multivalent metals. One or a mixture of several such compounds may be used together in the invention, depending on the nature of the polymeric system and according to the function required. Examples of preferred catalysts are zinc borate, zinc oxide, magnesium oxide, vanadium pentoxide, aluminum trioxide and manganese oxide. The catalytic effect expresses itself in an increase in the Ol values as well as in an increased UL94 rating. The amounts of catalyst (C) needed for the performance of the present invention are in the range of 0.0-20 weight %. The needed amounts of catalyst additive (C) may vary from compound to compound depending on the nature of the metalic element as well as of the anionic part of the salt. A feature of the present invention is that the effectivity of the additive (C) varies with the percentage added. For each catalyst there is an optimum concentration or concentration range, with maximum effect, above and below which the catalytic effect is diminished or disappears.
The functions of the metal compound catalyst are not unequivocally defined. There are several possible functions:
A. The additive acts as a pH regulator in the processing, storage, recycling and combustion. The additives (a) and (b) may release some strong acid traces and lower the pH of the material. This may lead to an excessive degradation of the polymer and to a deterioration of its physical properties. Whereas a limited degree of degradation is needed during the pyrolysis and combustion in order to facilitate the dehydration and the cross-linking, excessive degradation during processing is detrimental. The identity of (c) and its concentration are most important and have to be strictly regulated. It has been discovered that a similar buffering effect can be obtained by the controlled addition of a basic nitrogen derivative, such as melamine-additive (d), to replace (c) or in addition to it. This is already described in U.S. Pat. No. 5,424,344, in which melamine is a buffer in the process of treating polyamides with sulfamates.
B. Another function of additive (C) is as cross-linking catalyst. Many metallic compounds are known as cross-linking catalysts, as described by Harro Petersen in Handbook of Fiber Science and Technology, Vol. 11, Part A, Chemical Processing of Fibers and Fabrics, M. Lewin and S. B. Sello, Editors, Marcel Dekker Publishers, pages 205-210 (1983). The cross-linking can take place between 2 or more APP chains by the formation of bridges between them with the divalent or multivalent catalyst molecules. These bridges can be formed during processing or preferably during pyrolysis and combustion. Such bridges stabilize the APP and decrease its volatility during pyrolysis and combustion. It will increase the effective available concentration of the phosphorus and the stability of the char in which the APP participates. If the concentration is too low the effect is not noticeable and enhancement in flame retardant effectivity will be noticed. If, on the other hand, the concentration is too high, the APP will become highly cross-linked and inactive and the effectivity will decrease.
C. Another function of the catalyst additive (c) is the stabilization of the char. The integrity and mechanical strength of the char contribute greatly to flame retardancy. Low melting glasses, such as zinc borate have been used as flame-retardant and smoke-suppressing additives in conjunction with halogen for polyvinyl chloride [See R.E. Meyers et al., J. fire Sci. 3, 415-431, (1986)].
The fillers-additive (e) in the polymer mixtures according to the present invention may consist of uncrushed glass fibers of varying thickness and length, which may be coated or uncoated; mineral fibers, carbon fibers, aramide fibers, gypsum, wollastonite, lignin-containing fibers, etc. They may also include pigments, lubricants, mold - release agents, flow-enhancing agents, temperaturexe2x80x94stabilizing agents, impact modifiers and electro-conductive agents.
Other flame-retardant agents, such as halogen-containing additives, can be added to the composition and add some flame-retardant effect, if needed, to it. It is emphasized, however, that a most important advantage of the present invention is that no halogens and red phosphorus additives are needed to achieve high levels of flame retardancy as expressed by high OI and UL94 ratings.
The mixing and blending of the ingredients of the present invention can be carried out by any method suitable for obtaining uniform dispersions of particular solids such as mixing in the Brabender mixer or in an extruder or compounder.

Flame retardation of polymeric compositions


The present invention relates to a method of processing selected surfaces in a semiconductor process chamber by creating a temperature differential between the selected surfaces and contacting the surfaces with a reactant that preferentially react with a surface at one end of the temperature differential relative to the other selected surface(s). More particularly, the invention relates to the use of nitrogen trifluoride (NF3) gas for in situ cleaning of cold wall process chambers such as Rapid thermal Chemical Vaporization (xe2x80x9cRTCVDxe2x80x9d) systems.

The present invention relates to a method of processing a selected surface in a semiconductor process chamber by contacting the selected surface with a reactant that reacts preferentially with the selected surface relative to another surface when the selected surface is at a different temperature from the other surface. The invention is particularly suited for use in rapid thermal processing (RTP) systems. More particularly, the invention relates to the use of nitrogen trifluoride (xe2x80x9cNF3xe2x80x9d) gas to clean selected surfaces in RTP process chambers, including in Rapid Thermal Chemical Vapor Deposition (RTCVD) process chambers.
During the course of semiconductor device fabrication, a wafer undergoes many steps of processing. Some steps involve heating the wafer hundreds of degrees Celsius above ambient temperature. Unnecessary heating may lead to defective devices being formed on the wafer. One reason for this is that heat causes substances, such as implanted ions, to migrate outside their intended location on the wafer. Migration and other things affected by heating are compounded by the length of heating time and by the number of heat steps. To avoid the problems associated with wafer heating, it is advantageous to use processes that minimize the time that a wafer is kept at an elevated temperature. This is the principle of conserving the thermal budget of the wafer.
In a conventional process chamber using a tube furnace, for example, it might take several minutes to raise the temperature of the wafer to a desired level. Because the walls and other surfaces in such process chambers are directly heated along with the wafer, such systems can be referred to as xe2x80x9chot wallxe2x80x9d systems. The heated walls and other surfaces in the chamber also increase the wafer""s cooling time. Thus, in hot wall process chambers a wafer may be subject to prolonged heating and cooling.
In contrast, RTP process chambers use a radiant energy source, such as high intensity lamps, to rapidly heat a wafer to a desired temperature in a matter of seconds. The energy source may raise the wafer""s surface temperature by 75-125xc2x0 C. per second. Other surfaces in the chamber are not generally heated by the radiant energyxe2x80x94for example quartz liners and windows in the chamber may be transmissive of the radiant energy frequencies or the energy may not be directed onto the surfaces. Because the radiant energy source does not directly heat these surfaces, RTP systems may be referred to as xe2x80x9ccold wallxe2x80x9d systems.
Because the rapid heating and cooling in RTP systems conserve a wafer""s thermal budget, it was expected that RTP systems would be widely adopted for every heat-based process. However, RTP systems have certain disadvantages that have not been adequately addressed. One significant disadvantage is that radiant energy may not be absorbed uniformly by a wafer. This results in temperature variations in and across the wafer. Temperature variations lead to non-uniform process results. RTP systems therefore require sensitive systems for monitoring and controlling the temperature of the wafer. One useful system uses a parallel plate with a reflective coating that reflects energy to the backside of the wafer. An optic fiber collects and transmits the wafer""s backside emissivity to a detector that translates the frequencies of energy to a temperature reading. Unfortunately, a significant disadvantage of this temperature monitoring system is its vulnerability to certain cleaning processes carried out in an RTP process chamber.
This problem and certain others addressed by the present invention are illustrated in the following example: the deposition of polysilicon on a wafer in an RTCVD process chamber. Deposition of polysilicon is a known step in the fabrication of certain semiconductor devices. One notable process using polysilicon is the formation of hemispherical grained silicon (xe2x80x9cHSGxe2x80x9d). HSG formations enhance the storage capacitance in storage devices such as
Dynamic Random Access Memory Arrays (xe2x80x9cDRAMSxe2x80x9d). Poor, irregular HSG formations result in unclean RTCVD process chambers. (Methods for forming HSG are described, for example, in U.S. Pat. Nos. 5,634,974 and 5,759,262 which are hereby incorporated by reference as if set forth in their entirety.)
An undesired side effect from polysilicon deposition is that the polysilicon is deposited not only on the wafer but also on other surfaces in the process chamber. For example, in RTCVD process chambers, it accumulates on, among other things, the top quartz window and quartz liner of the chamber. A build-up of polysilicon impedes the transmission of radiant energy through the window onto the wafer. It may also lead to high particle counts in the chamber, lowering production yields. Therefore, periodic cleaning of the process chamber is necessary.
NF3 is a powerful etchant, effectively etching polysilicon and certain other substances used in semiconductor processing. Use of NF3 for in-situ cleaning of a non-RTP semiconductor process chambers is described in U.S. Pat. No. 5,797,195, to Hullinget al, entitled xe2x80x9cNitrogen Trifluoride Thermal Cleaning Apparatus and Process.xe2x80x9d The ""195 patent describes a xe2x80x9chot wallxe2x80x9d system for cleaning semiconductor fabrication equipment, including quartzware parts. NF3 gas is heated from approximately 100xc2x0 C. to 650xc2x0 C. by the existing heat source for the process chamber. At the same time, the heat source also heats the other surfaces in the process chamber, which surfaces the NF3 gas is free to contact. The ""195 patent does not teach or suggest that the described cleaning system is suitable for use in xe2x80x9ccold wallxe2x80x9d, RTP systems, including RTCVD systems.
It would be desirable to use NF3 gas to clean RTP process chambers, particularly those used to deposit polysilicon in HSG production. However, NF3""s high reactivity has so far limited its usefulness in this regard. NF3 cleaning, until the present invention, has not proved suitable for use in cold wall systems, such as RTCVD systems, because certain components in RTCVD chambers may be damaged by the high activity of NF3 at higher temperatures.
As the temperature of NF3 increases, its reactivity increases, converting to reactive species in the form of ionic fluorine and/or free fluorine. The temperatures that occur in RTCVD processing can exceed 750xc2x0 C. At such temperatures, NF3 is so corrosive that it attacks stainless steel, quartz, and silicon surfaces, damaging critical components found in RTCVD process chambers. As mentioned, temperature-monitoring systems based on wafer emissivity are particularly vulnerable to damage. NF3""s action on such unintended targets may also create unacceptably high particle counts in the process chamber, lowering production yields.
If the NF3 cleaning is performed at lower temperatures, the etching rate is too low to effectively clean the system. This is because most of the hardware inside the process chamber. including the top quartz window, is heated by heat transmitted from the wafer, not by light used to heat the wafer. Therefore, if the temperature of the wafer is low. the top quartz window is even cooler. This results in unacceptably low etching rates.
For the foregoing reasons, a method is needed that allows a reactant introduced into an RTP process chamber to act preferentially on certain surfaces. Among other things, such an improved method would allow strong etchants, such as NF3, to clean polysilicon deposits from process chambers without damaging sensitive components in the chamber.
The present invention overcomes the disadvantages of the prior art by providing a method by which a reactant may favor a reaction with selected surfaces in a semiconductor process chamber. In so doing, the present invention overcomes the problem of using a reactant that would act desirably on some surfaces and detrimentally on other surfaces.
The present invention provides a method that will facilitate the cleaning of RTP process chambers, thereby better facilitating the adoption and use of RTP systems. More particularly, the present invention overcomes the inherent disadvantages of using a powerful etchant, such as NF3 gas to clean an RTP process chamber.
The present invention also overcomes the problems of high particle counts and lowered production yields that result if NF3 gas or other strong etchant is used to clean RTP process chambers. Accordingly, the present invention also improves the process of HSG formation in RTP process chambers.
In overcoming the aforementioned disadvantages in the art, the present invention improves the efficiency and yield of semiconductor device production. Particularly, it improves the efficiency and yield of producing devices in RTP process chambers. More particularly, it improves the efficiency and yield of producing HSG formations on wafers using RTCVD systems.
One embodiment of the invention is a method of processing surfaces in a semiconductor process chamber, comprising: selecting two different surfaces in the process chamber, each surface at a given temperature being capable of reacting with a reactant introduced into the chamber; creating a predetermined temperature differential between the selected surfaces by allowing a heated object in the chamber to transfer heat to one selected surface so that surface becomes the surface at the higher end of the temperature differential; contacting the selected surfaces with a reactant present in the chamber during the predetermined temperature differential between the selected surfaces; and allowing sufficient time for the reactant to react preferentially with one surface to a predetermined degree. The reactant may be removed from the chamber after the reactant has reacted with a surface to a predetermined degree.
A method according to the present invention may also include repeating the foregoing steps following the processing of a predetermined number of work objects in the chamber. The foregoing method also provides for the removal of deposits composed substantially of polysilicon from the surface at the higher end of the temperature differential.
In the embodiments of the present invention, a selected surface at the lower end of the temperature differential may be cooled by a cooling means. The cooling means may be a fluid cooling system in conductive communication with the surface at the lower end of the temperature differential. Components of a temperature measurement system in the process chamber may be cooled to protect them against action by an etchant or other reactant.
The present invention may provide for the process chamber to include a reflectivity plate comprising a selected surface. The reflectivity plate is kept at the lower end of the temperature differential during cleaning by an NF3 gas or other etchant. By keeping the reflectivity plate at a lower temperature, it is protected from being damaged by an etchant that prefers reacting with other surfaces in the chamber kept at a higher temperature.
The present invention may also provide that a radiant energy source transmits energy to a work object thereby heating it. The surface of the heated work object radiates heat to a selected surface that becomes heated to the higher end of a temperature differential. The invention also provides that polysilicon may be etched off a surface that is transmissive of the radiant energy used to heat a work object in an RTP process chamber. One such transmissive surface may be the window between the radiant energy source and a work object. In the present invention, the etching of the transmissive surfaces occurs after they are heated by another object in the process chamber. That other object may be heated by the radiant energy source. Quartz surfaces in the chamber, including quartz liners and windows may be etched accordingly.
In another embodiment of the present invention, a method of cleaning an RTP process chamber is provided that includes the steps of heating a selected absorbent surface in the process chamber with energy from a radiant energy source, the radiant energy passing through a transmissive surface between the radiant energy source and the selected surface; allowing a selected transmissive surface in the chamber to heat by energy transferred from the selected absorbent surface, after the absorbent surface is heated by the radiant energy source; and contacting the heated transmissive surface with an etchant while there is a predetermined temperature differential between the selected transmissive surface and another selected surface in the chamber; and allowing sufficient time for the etchant to react preferentially at the transmissive surface to a predetermined degree relative to the other selected surface. Preferably, the selected absorbent surface comprises a wafer. The etchant in this embodiment may be NF3 gas. The other surface may be on a component of a temperature measurement system, such as a reflectivity plate. This embodiment is suitable for etching deposits on the transmissive surface, including polysilicon deposits. This embodiment also provides that the other surface may be cooled by a cooling means so that it is at the lower end of the temperature differential. For certain processes, particularly cleaning polysilicon deposits with NF3 gas or a similar etchant, it is advantageous to heat the selected absorbent surface to at least about 650xc2x0 C. to about 750xc2x0 C. so that it transfers sufficient heat to the selected transmissive surfaces to establish an appropriate temperature differential. More particularly, NF3 gas may be used to clean polysilicon from the transmissive surface by providing a selected temperature differential between the surfaces of at least about 200xc2x0 C. to about 500xc2x0 C., with the temperature of the transmissive surface with the polysilicon deposits at the upper end of the differential and being at least about 650xc2x0 C.
In still another embodiment of the present invention, a method of in situ cleaning of a process chamber is directed to running production wafers through a process chamber for depositing silicon on the wafers; stopping production runs for cleaning the chamber when silicon has deposited on the liner or a window of the chamber to a predetermined degree; heating a selected absorbent surface in the process chamber with energy from a radiant energy source, the radiant energy passing through a transmissive surface between the radiant energy source and the selected surface; allowing a transmissive surface in the chamber to heat by energy transferred from the selected absorbent surface; and, after a selected temperature differential has been established between the transmissive surface and another surface in the chamber, contacting an etchant present in the chamber with deposits on the transmissive surface. In this embodiment, as well as other embodiments, the selected absorbent surface may be on a silicon-based wafer. And the etchant may be NF3 gas. In this embodiment, as well as others, the selected temperature differential between the selected surface and other surface may be at least about 200xc2x0 C. Preferably, the selected temperature differential between the surfaces is from about 200xc2x0 C. to 500xc2x0 C. The temperature of the surface with the polysilicon or other material to be etched is at the upper end of the differential. A useful upper-end temperature for etching the selected surface with NF3 gas is at least about 600xc2x0 C. A preferable upper-end temperature for etching with NF3 gas is about 600xc2x0 C. to about 750xc2x0 C. However, in other embodiments, the temperature of the surface at the upper end of the temperature differential may be in excess of about 1000xc2x0 C., depending on the materials to be reacted.
Another embodiment of the present invention contemplates cleaning a semiconductor process chamber using a gas etchant. This embodiment is directed to heating an absorbent surface in the process chamber heat by energy from a radiant energy source, the absorbent surface being heated from about 400xc2x0 C. to about 1500xc2x0 C.; allowing a selected surface in the chamber to heat by energy transferred from the heated absorbent surface; and cooling another surface in the chamber so that there is a temperature differential between the cooled surface and the heated selected surface such that an etchant in the chamber reacts preferentially with the heated. Here again, the etchant may comprise NF3 gas. The temperature differential between the surfaces is also preferably at least about 200xc2x0 C.
As in other embodiments, the etchant may be NF3 gas. Again, a suitable temperature differential between the selected surface and other surface is at least about 200xc2x0 C.
The embodiments of the present invention are suitable for use in a cold-wall process chamber, particularly an RTCVD process chamber, used to form HSG capacitors on production wafers. When cleaning a process chamber of polysilicon deposits the polysilicon/silicon dioxide etching selectivity ratio may be in the range of about 4/1 to about 7/1, which will allow cleaning without unacceptable etching of other components in the chamber.
Other embodiments will be apparent to persons skilled in the art, which embodiments do not depart from the spirit and scope of the present invention.

Method of processing selected surfaces in a semiconductor process chamber based on a temperature differential between surfaces


A personal medical dictation system that can be easily and conveniently used to capture and preserve audio information. The system includes a specially designed portable, hand-held recording component that is of a small size, but yet is capable of storing at least one hour of actual dictation in compressed form and a cooperating dictation receiver that functions to automatically transfer the recorded data to a central processing area. The hand-held recording component can be expeditiously, mechanically, and electrically transmitted to the central processing area for transcription. The dictation receiver component also automatically recharges the batteries of the hand-held recording unit.

1. Field of the Invention
The present invention relates generally to a method and apparatus for collecting and preserving data. More particularly the invention concerns a method and apparatus for collecting and preserving medical information obtained by a physician using a personal medical dictator device and then preserving the data through the use of a novel dictation receiver apparatus.
2. Discussion of the Prior Art
Several devices have been suggested in the past for recording and preserving audio data. The most common of these devices is the conventional dictation recording device that records a user's dictation on a magnetic tape. The so-called prior art tape recorder reproduces the dictation by reading the recorded signal from the magnetic tape and preparing an electric signal representative of the recorded dictation. After the dictation is recorded, the user typically provides the magnetic tape to a typist who prepares a type written transcript. This is done by inserting the magnetic tape into a tape playing device which includes means for generating an acoustic reproduction of the dictation recorded on the magnetic tape. While listening to the reproduction of the dictation, the typist types a transcript of the dictation on the keyboard of a typewriter or word processing device.
In the past many physicians have made rather wide use of both hand-held and desk-mounted dictation devices to record their activities. The physician's description of interactions with patients whether in the office, in the hospital or in the operating room, are vital to the delivery of quality health care. Furthermore, documentation by the doctor is mandatory for legal purposes, to meet demands of regulatory bodies, and for effective business practices, including efficient billing, contractual compliance and the like. The permanent records of the physician's activities that are produced are typically kept in the medical record or "chart" of the patient.
When tape recorders are not used by the physician to record day-to-day activities, records are sometimes handwritten. On occasion the physician will also use a telephone to dictate notes to a remote receiving unit, usually located at a transcription location. At the transcription location a medical secretary or other typist transcribes the doctors spoken notes into text using a typewriter or word processor. The typed dictation is then placed in the medical record.
In other instances, the physician may use a hand-held digital recorder and electronically transfer the dictation directly to a personal computer. Several different types of digital recorders and the computer software to operably connect them to a personal computer are readily commercially available.
Each of the foregoing prior art techniques has its drawbacks. For example, when either a hand-held or desk-mounted tape recorder is used, the magnetic tape onto which the dictation is stored must be physically acquired and inserted into the recorder and then removed when the dictation is complete. The tape must then be physically delivered to the transcription location. During this process the tape can be lost, damaged, or recorded over prior to transcription resulting in the loss of crucial data. When using the tape recorder, access to prior dictation on the magnetic tape, or access to an earlier portion of the current dictation is slow and inconvenient because the tape must be physically rewound to the desired location.
With respect to telephone dictation, the physician must, of course, be in proximity to a telephone and the telephone must be available for use. If the telephone is not immediately accessible by the physician, time is lost in walking to the telephone and if the telephone is in use by another person, additional valuable time can be lost waiting for access to the telephone. In using the telephone to dictate medical records, the physician must dial the transcription location telephone number which may involve as much as a 12 digit number. Additionally, the physician must remember, or look up which numerical keys on the telephone are to be used to perform typical dictation functions. Once the transcription location is dialed, the physician must wait for the remote receiving unit to answer before dictation can commence. After the dictation unit answers, the physician must wait for instructions from the answering unit and then perform manual operations as directed as, for example, keying in the report type and the patient's record number. Finally, on each occasion, the physician must key in information that is constant as, for example, the physician's identification number and other data which does not change for a series of particular patients. All of these actions involve wasted motion and wasted time.
Problems concerning the use of prior art, hand-held digital recorders include the fact that most commercially available digital dictation devices are designed for general-purpose use and, therefore, have unnecessary keys and functions that complicate their use for medical dictation. Additionally, presently available digital recording devices require that a physical connection be made for re-charging and for data transmission from the recording device to a receiving device, such as a personal computer that is necessarily located in the immediate vicinity of the digital recorder. Finally, existing digital recording devices require that a computer program be run on the receiving computer in order for the dictation to be transferred from the device into the memory of the computer so that the transcription activity can be performed.
One example of the aforementioned type of prior art voice recording system is disclosed in U.S. Pat. No. 5,389,220 issued to Barker. The Barker system includes a portable voice recording device having a microphone for generating an electrical signal representative of an acoustic speech signal. An analog to digital converter receives the electric signal from the microphone and generates a digital memory signal representative of the electric signal. A memory device stores the digital memory signal. In response to a user's request, a digital to analog converter converts the memory signal to an analog electrical signal which drives a loud-speaker to generate an acoustic reproduction of the original speech signal. Somewhat similar Barker dictation recording devices are disclosed in U.S. Pat. Nos. 5,548,566 and 5,818,800 also issued to Barker. While the Barker systems represent significant advance in the art, to effect the transfer of the dictation from the recording device of the receiving machine, the user must still be somehow "tethered" to a personal computer. Also, manual processes, such as installation and operation of receiving software, are required
As will be better understood from the discussion which follows, a primary object of the present invention is to overcome the drawbacks of the prior art data recording and preservation systems as described in the preceding paragraphs by providing a simple, easy to use and highly efficient personal medical dictation system that facilitates the recording of the physician's dictation and the subsequent automatic transmittal of that dictation without effort on the part of the physician to a non-contiguous central location from which transcription quickly and efficiently can take place.

Dictation system capable of processing audio information at a remote location