Abstract: A typical method for bonding a die to a substrate includes the steps of placing a solder preform onto the substrate, contacting the die to the preform and applying heat sufficient for the solder to flow and wet the substrate and die forming a bond therebetween. The present invention comprises heating the substrate and preform to a temperature below the melting point of the solder preform and thereafter maintaining this temperature while applying pressure to the preform sufficient to substantially reduce the thickness of the preform and to cause the preform to adhere to the substrate prior to contacting the die thereto.

Abstract: Yttrium aluminum garnet is employed as a light-transmissive window for electro-optic device packages. This material is resistant to high amounts of atomic radiation.

Abstract: The invention is an improved avalanche photodiode having reduced electrical noise arising from spurious surface generation of charge carriers. The avalanche photodiode includes active and neighboring regions adjacent a first surface of a semiconductor body with a gap region therebetween and a channel extending a distance into the semiconductor body from a portion of the second opposed surface opposite the gap region. A P-N junction is formed between regions of opposite conductivity type including a portion thereof over the channel. Since the dopant concentration at the junction is less over the channel, the local avalanche gain over the channel is less, thereby reducing the noise contribution from carriers generated in the gap region.

Abstract: The formation of elongated structures, such as lines, having a linewidth substantially less than one micrometer is described. An elongated structure of a first material having opposed sides, a rounded surface between the sides and a width typically of about one micrometer or greater is formed on a substrate. The sides of the structure are at least partially coated with a layer of a second material which will etch at a slower rate than the first material. The coating may completely cover the structure. The structure is anisotropically etched. Since the coating protects the sides of the structure, etching proceeds in the center to form two parallel lines, each significantly below one micrometer in width. In one embodiment, formation of the protective coating and etching of the structure are carried out simultaneously.

Abstract: A semiconductor laser comprising a substrate having a plurality of closely spaced channels in the surface thereof with mesas separating the channels to form a channelled region in the surface of the substrate. A first cladding layer overlies the surface of the substrate and the channels and has a surface layer over the channelled region which is not coplanar with the surface of this layer over the surrounding substrate. A cavity region comprising a guide layer and an active layer overlies the first cladding layer and a second cladding layer overlies the active layer. The active layer and guide layer taper in thickness in the lateral direction.

Abstract: Crystalline quality of a semiconductor material near its interface with an insulator is evaluated by the photovoltage response to a light beam scanned in wavelength. The crystalline quality is determined from the photovoltage interference pattern in the region of intrinsic excitation of the material. A body of silicon-on-sapphire (SOS) is used to illustrate the method.

Abstract: The invention is an improved electrooptic assembly which comprises an electrooptic device mounted on a header and enclosed by a cover with a light-transmissive window mounted therein. The header includes a base plate with two major surfaces and a minor surface connecting the major surfaces with a segment of the cover attached to the minor surface. The minor surface is non-perpendicular to the major surfaces, thus allowing adjustment of the position of the window to achieve optimum emission or detection.

Abstract: A method is disclosed for making a termination between (a) a fiber optic cable having a centrally positioned optical fiber, a plurality of reinforcement strands positioned about the optical fiber, and a jacket positioned about the reinforcement strands; with (b) an electro-optic component housing having a tubular extension. In accordance with the method of this invention, in the initial step a predetermined length of the outer jacket is removed from the fiber optic cable to expose a length of optical fiber and reinforcement strands. The optical fiber is then inserted into and through a passage in the tubular extension to a point within the component housing and preferably fixed in place. The reinforcement strands are then positioned about the outer diameter surface of the tubular extension so that portions of the outer diameter of the tubular extension are covered with the reinforcement strands and other areas are left exposed.

Abstract: A phase-locked semiconductor laser array includes a plurality of channels in a surface of a substrate with lands therebetween with laser oscillation occurring in the cavity region over each of the channels. The individual oscillators are coupled by the overlap of their evanescent fields to produce a phase-locked array. Phase-shifting means are included in alternate channels to ensure that the laser light emitted by the different lasing regions are in phase with one another. Preferably the phase-shifting means comprise portions of each of alternate channels having a different spacing from the cavity region than that of the remainder of the channels.

Abstract: The use of o-cresol novolac resin for planarizing large topographic features on a semiconductor substrate is disclosed. In addition to being a superior planarizing material, o-cresol novolac resin oxidizes and darkens upon baking to provide excellent absorption capability for the light wavelengths which are conventionally utilized to irradiate photoresist compositions. O-cresol novolac resin additionally transmits light at higher wavelengths which are used to align pattern masks with alignment keys on a substrate. These properties further make a transparent substrate coated with a patterned layer of o-cresol novolac resin useful as a lithographic mask.

Abstract: Multilayer photoresist recording media containing an absorptive layer are improved by forming the absorptive layer from a composition comprising PMMA or a copolymer of methylmethacrylate and methacrylic acid, certain dyes such as hydroxyazobenzoic acid or Sudan Orange G and a suitable solvent. The dyes are insoluble in the solvent of an overlying photoresist layer. The media are substantially free of loss of resolution due to dissolution of the dye into the photoresist layer.

Abstract: A die bonder for bonding a semiconductor die to a substrate is disclosed. The die bonder comprises a support assembly within a frame, which assembly supports an arm. Attached to said arm is a means for holding a die, e.g. a vacuum collet. A variable electrical scrubbing means comprises a plunger which oscillates reciprocally within an electromagnetic coil and contacts the arm, or a tab integral with said arm. This provides a corresponding uniform scrubbing action, perpendicular to said arm in the plane of the interface between the die and the substrate, between a die held by the holding means and a solder material interposed between the die and substrate.

Abstract: The erosion rate of a layer of negative-working resist is markedly reduced by forming thereon a thin layer of polyfunctional acrylate or methylacrylate monomer. Upon irradiation, the monomer insolubilizes at a faster rate than the resist thereby forming a crust thereon. The result is reduced erosion, improved edge acuity and fewer pinholes in the developed resist pattern.

Abstract: An improved method of selectively depositing coatings onto bodies of semiconductor material employs as a protective mask an alkyl ester of a sulfosuccinate salt. The mask material is applied to areas which are to be kept free of the coatings. The overspray of a desired coating, onto the protective mask is deposited in a cracked, non-continuous manner, as opposed to the smooth crystalline layer being deposited over the semiconductor body. This overspray coating can be readily removed.

Abstract: A process of bonding a coating of a polyurethane resin to a polyolefin substrate is provided. The polyolefin substrate is coated with a graft copolymer of a polyolefin and a functional monomer such as acrylic acid. The graft copolymer is flame treated to fuse it. A liquid polyurethane precursor composition is then applied thereto and cured.

Abstract: A method of determining the presence of alkali metal ions in a substrate comprising silicon or silicon doped with a p-type conductivity modifier is provided. The substrate to be tested is etched in a tetrafluoromethane/oxygen plasma and the etch rate is compared against that of similar substrates containing known concentrations of alkali metal ions. The etch rate will increase with increasing alkali metal concentration. The subject method is particularly useful in determining the level of alkali metal ion contamination during multistep processing of the above-named substrates.

Abstract: Polycide structures are etched with silicon tetrachloride. The etch is preferably carried out at a pressure of about 20 to 60 mtorr and overetching to remove stringers is then carried out at an increased pressure, i.e. at least about 100 mtorr. There is obtained an anisotropic etch with substantially no stringers or linewidth loss. When selectivity of etch vis-a-vis an underlying layer of gate oxide must be enhanced, from about 60 to 90 percent by volume of the silicon tetrachloride is replaced with chlorine just prior to completion of the etch.

Abstract: A process of forming improved ohmic contacts is disclosed. Substrates having contact openings formed in a dielectric layer thereon are cleaned under vacuum with HF/H.sub.2 O vapor wherein the temperature of the vapor is at least about 5.degree. C. lower than that of the substrate. The cleaned substrates are then metallized in-situ in a closed system, e.g. by magnetron sputtering, thus preventing air from contacting the substrate. The cleaning and metallization each require about one minute, thus making the process suitable for efficient, large-scale operation.

Abstract: A multi-emitter semiconductor electroluminescent device includes a stud having a mounting block on a surface thereof and a cover extending over the mounting block and secured to the stud. The mounting block has a plurality of surfaces which are angled toward a common point. A separate electroluminescent semiconductor element is mounted on each of the surfaces of the stud and have light emitting surfaces which face toward the common point. The electroluminescent elements are electrically connected to lead wires so that they can be operated either individually or simultaneously. An optical fiber extends through the cover and has one end directly over the common point so that the light emitted from all of the electroluminescent elements will enter the end of the optical fiber and propagate along the fiber.

Abstract: A p-type impurity in a silicon semiconductor structure is at least partially neutralized by exposure to atomic hydrogen. The subject method provides an excellent means of modifying the profile of the impurity. Suitable impurities include boron, aluminum, gallium and indium.