Abstract: The major portion of the crucible in which a compound semiconductor ingot is grown has an inner surface which, in a section taken transverse to the crucible axis, substantially defines an ellipse. As a consequence, the ingot grown in the crucible has an elliptical cross-section. After the ingot is removed from the crucible, it is cut at an angle with respect to the central axis of the ingot and in the direction of the minor axis of the ellipse defining the ingot cross-section. Wafers cut from the ingot will have a circular periphery if the sine of the angle at which they are cut substantially equals y.div.x where y is the thickness of the ingot along the minor axis of the ellipse, and x is the thickness of the ingot along the major axis of the ellipse.

Abstract: A semiconductor optical device, such as a photodetector or a semiconductor laser, is sealed by a Langmuir-Blodgett film that intercepts the optical path extending from the device. The film is less than one-thirtieth of a wavelength at the operating optical frequency, which precludes interference with transmitted light waves.

Abstract: A compressible thermally conductive member comprises a polymer field with thermally conducting-magnetically aligned particles comprising a base portion and a multiplicity of protrusions extending from at least one surface of the base portion.

Abstract: In accordance with the invention, the functions of two TV cameras in the prior art for monitoring polymer coating concentricity and/or carbon coating thickness are accomplished by a single TV camera (48). Rather than being projected onto an opaque dispersive screen, the forward-scattered mode pattern of each of the orthogonal beams (57,58) is transmitted through a translucent screen (52,53) and reflected to an image combining device (67) which transmits both patterns to the single TV camera (48). The two beams are slightly vertically displaced to establish displaced images (72,73) of the two patterns. This allows the two patterns to be viewed simultaneously and distinguished by the TV camera. Modified electronics (FIG. 10) provide for alternate TV scanning of the two images so that a computer (22) can monitor and correct concentricity and/or carbon coating thickness in real time during fiber production.

Abstract: The problem of spurious inclusions of excess Group V material in the growth of III-V crystals is reduced by including, along with the raw material (12) in the crucible, a quantity (13) of the elemental Group V material and encapsulating with boric oxide (14). The crucible is contained within a growth vessel (19) which is in turn contained within a pressure vessel (16) which is first evacuated and then filled to a high pressure with an inert gas such as argon. The inert gas is one which is lighter in weight than the vaporized Group V material, and which is at a higher pressure than the equilibrium pressure of the vaporized Group V material at the melting temperature of the III-V compound. The vaporized Group V material displaces the argon in the growth vessel (19). The inventive process also reduces defects in the grown crystal.

Abstract: In a VGF process for growing a large single crystal 16' in a crucible 11, the problem of stress forces caused by a freezing liquid encapsulant are solved by using a step or indentation 21 around the inner surface of the crucible 11 at or near the top of the single crystal 16' being grown. As a consequence, the newly-frozen single crystal (e.g., InP)conforms to the shape of the indented inner surface of the crucible and therefore has a pronounced bulge 22 near its top. The bulge of the frozen semiconductor crystal then nests against the indentation on the periphery of the crucible, thereby to prevent any liquid encapsulant from flowing between the crystal and the wall of the crucible.

Abstract: A glass soot deposition torch (30; FIG. 2) having gas passages arranged to provide an inner (34) and outer (36) flame front is disclosed in which the temperature of the inner front is higher than the outer front. A passage is located within the outer front (36) through which glass soot (32) is directed onto the surface of a growing soot-form core (38).

Abstract: In a hybrid integrated circuit encapsulation process, each lead array (14) is encompassed by an elongated C-shaped barrier member (17) which clamps onto the portions of the lead array adjacent the substrate (11); that is, opposite sides of a slot (18) in the barrier member grasp opposite sides of the leads. Thereafter, the uncured RTV silicone (15) is dispensed onto the substrate, flows over and encompasses chips (12) mounted on the surface of the substrate and is prevented from flowing along the leads (14) by the C-shaped members (17), each of which, due to its configuration, constitutes a barrier to fluid flow, either along the length of the various leads or over the top of the C-shaped member. In one embodiment, levers (19) may be integrated onto the C-shaped member opposite the substrate to aid in prying open the slot to permit the leads to be easily inserted into the C-shaped member.

Abstract: Photomasks (11, 12) are aligned on opposite sides of a wafer by directing light beams through zone plates (13 A-C) in one photomask and through aligned transparent slits (14 A-C) on the other photomask. Simulantaneous detection of the beams by photodetectors (18 A-C) indicates alignment. A method for obtaining precise centering by scanning the slits with the beams, sampling light transmitted through the slits, and fitting the samples to a parabola by the use of a computer (27) is also described.

Abstract: An article of manufacture comprising an electron device encapsulated by a silicone resin material consisting essentially of 15 to 30 weight percent of polydimethylsiloxane and/or polymethylphenylsiloxane resin including a platinum catalyst, 50 to 80 weight percent of silicon dioxide and 5 to 20 weight percent of a silicon hydride.

Abstract: A circuit package comprises at least one IC chip bonded directly in a hole provided in a wafer such that the surface of the chip and the surface of the wafer are in the same plane thereby accommodating TAB bonding of the chip to bonding pads provided on the wafer. The structure can include multilayer circuitry on the wafer.

Abstract: Laser welding of an outer sleeve 14 to an inner fiber ferrule 12 is expedited by, first, machining a thinned region 18 in the outer diameter of the sleeve. After the ferrule has been inserted in the sleeve, the thinned region permits the laser to fuse through the sleeve and melt part of the ferrule, as is required for laser welding of ferrule for the sleeve. The thinned region is preferably made by using a rotary cutter to cut an axially extending slot in the outer sleeve, which permits a succession of laser welds 21 in the axial direction in the slot. In a preferred embodiment, thinned regions 18,19 are made on opposite sides of the outer sleeve, and laser welding is performed simultaneously on both sides of the sleeve so as to avoid distortions caused by thermal stress asymmetries.

Abstract: Surface defects on a substrate (11) are detected by raster scanning the surface (10) with a laser beam (12). Light scattered by the substrate at a large angle with respect to a normal to the surface is collected by at least two bundles of light guide fibers (21,22) located nearly in the plane of the substrate surface, one fiber bundle parallel to the laser scan with the other positioned perpendicularly thereto. The light collected by each bundle is separately processed by a computer (20) to determine the size, in three dimensions, and orientation of defects on the substrate surface. In a preferred embodiment, four light guide fiber bundles (31,32,33 and 34) are used around the substrate surface with the outputs being separately processed.

Abstract: In accordance with one embodiment of the invention, a process for interconnecting the circuitry of two substrates comprises the step of terminating the circuitry on bonding pads that are arranged in parallel rows with the first row of each substrate being nearest an edge of the substrate. The bonding pads of the two first rows of the two substrates are joined by conductors of a dielectric tape that bridges the two substrates. The conductors overlap the edges of the dielectric tape and are organized to permit them to be bonded to corresponding bonding pads of the two substrates, for example, by soldering. The two second rows of bonding pads are joined by conductors on a second dielectric tape which is wide enough to cover two first rows of bonding pads and thereby provide electrical insulation.

Abstract: The fabrication of a printed circuit board (26) usually includes the step of testing the board with a testing machine (24) to verify operability. The testing machine accomplishes such testing by transmitting test signals to the board via a transmission line (36) and then analyzing each response signals returned from the board in response to the test signals. To reduce the incidence of error, the testing machine (24) is compensated for the propagation delay of the line (12) which is measured by launching a first string of pulses into one end of the line whose opposite end is left open. A second string of pulses is simultaneously launched into a programmable delay line (16) which delays each second pulse by an adjustable interval. After the generation of each first and second pulse, a check is made whether the first pulse has been reflected back to the first end of the transmission line at the same time the second pulse reaches the output of the delay line.

Abstract: A compressible thermally conductive member comprises a polymer field with thermally conducting magnetically aligned particles comprising a base portion and a multiplicity of protrusions extending from at least one surface of the base portion.

Abstract: Photomasks (11,12) are aligned on opposite sides of a wafer by directing light beams through zone plates (13 A-C) in one photomask and through aligned transparent slits (14 A-C) on the other photomask. Simultaneous detection of the beams by photodetectors (18 A-C) indicates alignment. A method for obtaining precise centering by scanning the slits with the beams, sampling light transmitted through the slits, and fitting the samples to a parabola by the use of a computer (27) is also described.

Abstract: In an image reversal process (12), a photoresist coating on a wafer is baked in an oven (19) in the presence of amine gas to fix the exposed photoresist portion (14). A computer (21) is programmed with a characterization of the photoresist film. The output of a temperature sensing element (23) mounted on the wafer is directed to the computer which, in response, controls introduction of the amine gas and withdrawal of the wafer after a predetermined extent of reaction in the coating.

Abstract: A multilayer protective device is made by including a varistor composition (35) between a first plurality of interdigitated electrodes (30, 32) and a capacitor composition (36) between a second plurality of electrodes of the same device. The two compositions are chosen to have optimum sintering temperatures within about 10 percent of each other. Simultaneous sintering solidifies and laminates the two compositions into a single monolithic device.

Abstract: A method of extending the shelf-life of an uncured silicone resin formulation which includes a primary amine therein comprises adding an acid to the formulation in a molar quantity approximately equal to the number of moles of primary amine present in the formulation, said acid being volatile at or below the curing temperature of the resin formulation.