At&t Bell Laboratories

At+t Corp.

Lucent Technologies Inc.

At&t Ipm Corp.

Ching-Ping Wong

Ivan Pawlenko

Peter F Lilienthal, Ii

Robert William Filas

Bertrand H Johnson

Richard L McBride

Minute quantities of water in a terpene cleaning solvent cause a reaction with certain metals, particularly lead, tin and copper, which reactions are responsible for corrosion of the metal. Such reactions can be reduced or substantially eliminated by exposing the cleaning solvent to a molecular sieve prior to the cleaning operation. The molecular sieve typically includes a plurality of beads of zeolite to which the cleaning solvent is exposed. The molecular sieve traps the water molecules from the solvent so that, after treatment, the solvent contains substantially no water molecules.

Method for cleaning an object soldered with a lead-containing solder

The specification describes a cleaning process for electronic devices and assemblies such as printed wiring boards. In the cleaning process deterioration of a terpene based cleaning solution, as evidenced by yellowing, is prevented using a copper chelating additive.

Cleaning with limonene, BHT, and acetylacetonate

In a method for cleaning using terpene compositions, the generation of harmful precipitates is substantially eliminated or significantly reduced by adding a polar solvent, such as isopropyl alcohol, to the terpene composition. One to twenty percent of the cleaning composition should be alcohol, although it is preferred that it be in the five to fifteen percent range. The upper limit reflects primarily the desire to reduce the flammability of the solvent. Alternatively, the electronic devices can be rinsed with a terpene, alcohol mixture, but this alternative is much less preferred because of the flammability problem.

Terpene-based method for removing flux residues from electronic devices

An electronic device (12, 13) is substantially enclosed by a fluid encapsulant (17). The fluid encapsulant consists essentially of a silicone resin and a catalyst selected from the group consisting of platinum and tin. The silicone resin is selected from the group consisting of polydimethlysiloxane, polymethylphenylsiloxane, polydimethyldiphenylsiloxane, and mixtures thereof. Such silicone resins comprise molecules terminating in vinyl components and hydride components. The molar ratio of vinyl components to hydride components is maintained within the range of five to twenty. As will be explained more fully later, this ratio of vinyl components to hydride components assures that the resin will remain substantially a liquid even after cure, due to limited cross-linking or polymerization during the cure. The electronic device is contained within a container (16) having a sealed cover (18) for containing the liquid encapsulant during the operation of the electronic device.

Method of encapsulating an electronic device

Glass particles (14) are mixed within an uncured silicone resin (13). The fluid uncured resin is placed in a portion of a terminal block (11) and cured to form a gel (13') by subjecting it to microwaves in a microwave oven (22). Conductors (25, 26) to be interconnected are next inserted into the cured silicone gel and interconnected. The cured gel containing the glass particles thereafter constitutes a dependable insulator for the conductors, particularly the portions of the conductors that are interconnected.

Method for encapsulating electronic conductors

Problems resulting from contamination of electronic apparatus used with silicone keypads can be eliminated or substantially reduced by soaking such keypads prior to assembly in a low molecular weight liquid hydrocarbon, particularly n-hexane. Such soaking removes low molecular weight unreactive cyclics from the keypad which might otherwise contaminate the electronic apparatus.

Method of treating structures including silicone materials

A module, such as a terminal block (10), configured of a body (12) having an open end (20) and at least one window (24) spaced from the open end, is fixtured and sealed by way of a channel (28) comprised of a pair of parallel, spaced-apart, generally elastic walls (30,32) jointed by a bottom member (34). The walls (30,32) and the bottom member (34) run longitudinally a distance at least as long as the width of the terminal block (10) to allow the block to be received between, and to be held by, the walls. At least one protrusion extends out from a separate one of the walls (30,32) and the base member (34) for receipt in the window (24) in the terminal block to seal the same.

Apparatus for fixturing modules

An encapsulant comprised of alternate layers of polymer and glass gives enhanced protection to semiconductor integrated circuit devices, which is much more effective than either glass or polymer encapsulations by themselves. In one embodiment, a semiconductor device (11) is covered by a polymer layer (13), the polymer layer being covered by a glass layer (14), and the glass layer being covered by a second polymer layer (15). The glass is preferably deposited by a plasma enhanced chemical vapor deposition apparatus (17 of FIG. 2 ).

Encapsulation techniques which include forming a thin glass layer onto a

Silicone resin is used by adding, to the uncured silicone resin, platinum suspended in a liquid carrier which is miscible in the silicone resin, the liquid carrier being selected from the group consisting of silicone oil and liquid hydrocarbon materials. The platinum preferably consists of particles of essentially pure platinum, each particle having a diameter of less than ten microns. The ratio of the platinum to the silicone resin is preferably in the range of three to ten parts per million.

Method for curing silicone resins

Method for fixturing modules

In a preferred embodiment of the invention, a substrate (11) is cleaned by immersing it in an organic solvent (17) and subjecting it to acoustic energy, immersing it in alcohol, immersing it in a surfactant, subjecting it to a cascading rinse in deionized water, baking it (FIG. 3 ), and thereafter subjecting it to ultraviolet light in an ozone ambient (FIG. 4). When the foregoing steps are followed, the contact angle is significantly reduced, and an encapsulant (14) that is thereafter applied provides more reliable protection to an encapsulated device (12) from outside contaminants.

Methods for encapsulating electronic devices

An electronic device (12, 13) is substantially enclosed by a fluid encapsulant (17). The fluid encapsulant consists essentially of a silicone resin and a catalyst selected from the group consisting of platinum and tin. The silicone resin is selected from the group consisting of polydimethylsiloxane, polymethylphenylsiloxane, polydimethyldiphenylsiloxane, and mixtures thereof. Such silicone resins comprise molecules terminating in vinyl components and hydride components. The ratio of vinyl components to hydride components is maintained within the range of five to twenty. As will be explained more fully later, this ratio of vinyl components to hydride components assures that the resin will remain substantially a liquid even after cure, due to limited cross-linking or polymerization during the cure. The electronic device is contained within a container (16) having a sealed cover (18) for containing the liquid encapsulant during the operation of the electronic device.

Encapsulant method and apparatus

A silicone gel encapsulated integrated circuit (12) is placed in a container, the container being partially filled with a silicone elastomer (16) which is much more rugged than the gel. After the elastomer (16) hardens, it completely covers the gel encapsulation (14) and protects it and the integrated circuit device from the effects of rough handling. The gel, however, gives all of the protection from the external environment that it would in the absence of the elastomer encapsulation.

Method for encapsulating integrated circuit

Devices are described in which certain crosslinked silicone polymers are incorporated. These polymers have various functions such as encapsulating agents, surface protective agents or agents to index match optical components (e.g. optical fiber, optical waveguide, etc.) to other optical devices or articles. The polymer is a vinyl-terminated dimethyldiphenylsiloxane copolymer crosslinked with tri- or tetrafunctional silanes in the presence of a platinum catalyst. The phenyl group content of the crosslinked silicone copolymer is adjusted to change the index of refraction of the polymer to the optimum for the particular application contemplated. Polymer preparation procedures are described which yield good optical quality for the polymer as well as optimum physical and chemical properties.

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Lawrenceville, NJ, United States of America

Ching-Ping Wong