Abstract: A lightguide preform is fabricated by depositing a thin carbon layer (40) on a cylindrical glass mandrel (30) and further depositing a plurality of glassy soot layers (32) thereover. The resulting composite structure is heated, in a furnace, at a low temperature to remove the carbon layer (40) and then heated at an elevated temperature to consolidate the glassy soot layers on the glass mandrel to form the lightguide preform.

Abstract: A technique for condensation soldering of articles (29) in a facility (40 or 80) having a vapor chamber (42) and a pair of aligned input (102) and exit (104) throats. An article (29) to be soldered is transported sequentially through the input channel (56), the vapor chamber (42) and the output channel (58). Simultaneously, air is moved, in a controlled manner, into and through a portion of the exit channel, in a direction opposite to the movement of the article and withdrawn from the input channel. The air exiting the input channel is processed to recover the expensive vapor entrained therein.

Abstract: A plurality of spring clips (30), each having an elongated central member 2) with first (40) and second (38) ends and a plurality of resilient arms (36) radially extending therefrom, are simultaneously transferred between a transfer plate (90) and a pallet (20). The first ends (40) of the member (32) are lockably engaged in the transfer plate (90) with the second ends (38) thereof positioned into apertures (24) in the pallet (20). The central member (32) is rotated to release the first ends (40) from the transfer plate (90) while simultaneously lockably engaging the second ends (38) to the pallet (20) to secure the clips (30) therein and to capture a chip carrier (10) between the ends of each arm (36) and the pallet (20).

Abstract: A plurality of spring clips (30), each having an elongated central member (32) with first (40) and second (38) ends and a plurality of resilient arms (36) radially extending therefrom, are simultaneously transferred between a transfer plate (90) and a pallet (20). The first ends (40) of the member (32) are lockably engaged in the transfer plate (90) with the second ends (38) thereof positioned into apertures (24) in the pallet (20). The central member (32) is rotated to release the first ends (40) from the transfer plate (90) while simultaneously lockably engaging the second ends (38) to the pallet (20) to secure the clips (30) therein and to capture a chip carrier (10) between the ends of each arm (36) and the pallet (20).

Abstract: The height of solder bumps (10) on a bonding pad (24) of a semiconductor chip (12) is increased by successively immersing the chip in molten solder alloys having progressively lower melting points.

Abstract: Individual defects in or near the surface of a silicon wafer (16) are detected by directing a time-modulated laser beam (44), having an energy level above the bandgap energy of the silicon material, towards the wafer. The beam (44) is focused to a one to two micron spot (48) on the wafer surface to photoexcite (i.e., pump) a high density of electrons and holes which changes the infrared reflectance in the area of the pumped spot. A probe beam (34) of infrared radiation is directed at the surface (0.126 square mm in area) of the substrate (16) and at a small angle thereto and the reflection thereof monitored by a detector (54). The pumped spot (48) is raster scanned within the area of the probe beam spot (38). The detector (54) detects only that portion of the intensity of reflected probe beam (34) that is modulated by the pump beam frequency to create a video display having a high spatial resolution showing individual defects.

Abstract: A process of laser-induced metal deposition for repairing transparent defects (18) in patterned metal films (14) of photomasks (10). The process comprises the steps of (a) coating the surface (16) of the substrate (12) having the film (14) thereon with a layer of metal-organic compound (50); (b) exposing the portions of the layer of metal-organic compound (50) overlying the defects (18) to a beam (24) of electromagnetic radiation from a laser (22); (c) ramping the power level of the radiation beam (24) delivered by the laser (22) until a metal patch (52) is reflective and adherent is formed; and (d) removing the unexposed portions of metal-organic compound (50) remaining on the substrate surface (16).

Abstract: Control over the diameter variations in a glass rod (10) during the stretching thereof is accomplished by cooling the rod after heating and initial neck down of a portion (22) thereof. After cooling, the rod (10) is reheated, at a lower temperature sufficient to reflow the glass in the necked-down portion (22) thereof, and is then stretched to the desired final diameter. Heating the rod (10) at a lower temperature during stretching increases the viscosity thereof which reduces its response to the stretching conditions, thereby affording better control over diameter fluctuations.

Abstract: A high temperature induction furnace (10) for drawing lightguide fiber (52) from a silica preform (44) has an axially located tubular zirconium dioxide susceptor (34) therein. Prior to use, at least a portion of the inside surface of the susceptor (34) is coated with a vapor deposited silica "soot" (54). The silica soot (54) is then consolidated at an elevated temperature. Surprisingly, such a technique substantially eliminates migration of zirconium dioxide particles from the susceptor (34) to the preform (44) and/or the fiber (52) without deleteriously affecting the susceptor (34) and/or the operation of the furnace (10).

Abstract: A multipoint dispensing of viscous material onto a board (23) comprises the monitoring and controlling of several process parameters such as the initial gap (.delta.) between a dispensing tool (20,25) and the board (23), the dispense pressure time cycle within the tool (FIG. 3A) and the tool velocity cycle (FIG. 3B). Also, an improved method for loading solder paste into the dispensing tool includes applying vacuum to two regions of the tool while vibrating it in its axial direction (FIG. 4). Furthermore, improved techniques for preventing crust formation on the paste within the tool, and for controlling the viscosity of the solder paste within the tool, achieve consistent dispensing results in a production environment.

Abstract: An apparatus (30) for cooling a lightguide fiber (21) drawn from a molten portion of a glass preform (22) located in a furnace (23). The apparatus (30) has an upper chamber (34) and a lower chamber (36) each having a small opening in the lower portions thereof. The upper chamber (34) has a heat transfer liquid (35) therein and the lower chamber (36) is pressurized to prevent liquid from passing through the opening. The hot fiber (21) is cooled by the liquid as it is drawn through liquid (35) without physical contact with the periphery of the openings.

Abstract: A plurality of spring clips (30), each having an elongated central member (32) with first (40) and second (38) ends and a plurality of resilient arms (36) radially extending therefrom, are simultaneously transferred between a transfer plate (90) and a pallet (20). The first ends (40) of the member (32) are lockably engaged in the transfer plate (90) with the second ends (38) thereof positioned into apertures (24) in the pallet (20). The central member (32) is rotated to release the first ends (40) from the transfer plate (90) while simultaneously lockably engaging the second ends (38) to the pallet (20) to secure the clips (30) therein and to capture a chip carrier (10) between the ends of each arm (36) and the pallet (20).

Abstract: A lightguide furnace (10) includes a tube (32) at its base. The tube (32) has at least one opening (34) therethrough, in communication with, but substantially misaligned relative to, a corresponding opening (40) through a sleeve (36) coaxially aligned with, and rotatable about the tube (32). The substantial misalignment between each sleeve opening (40) and each tube opening (34) causes the cooling gas entering the furnace to be directed at least partially around the lightguide fiber (14). The cooling gas passes upwardly along the walls of the furnace away from the lightguide fiber (14) to reduce the likelihood of contamination thereof by particulates in the cooling gas. By rotating the sleeve (36) relative to the tube (32), the degree of misalignment of the sleeve openings (40) relative to the tube openings (34) can be adjusted to control the lightguide fiber cooling to regulate the tension.

Abstract: A lead frame (10) having external leads (26--26) and internal leads (22--22). The internal leads (22--22) are made of soft metal to provide bondability to ceramic substrates having a semiconductor chip thereon while the external leads (26--26) are hard metal to facilitate insertion thereof into a PWB. The lead frame (10) is fabricated by providing a hard metal strip (50) with a soft metal stripe (52) along the central portion thereof. Lead patterns (17--17) are punched in the strip (50) in such a manner as to punch the internal leads (22--22) from the soft metal while simultaneously punching most of the external leads (26--26) from the hard metal. The stripe (52) may be formed by annealing, inlaying or a separate piece of soft metal bonded to two outer hard metal sections (56--56).

Abstract: Chip carriers (10--10) are released from an end of a dispensing means (38) drawn across a holder (22) having a plurality of apertures (28--28) therein, to place a carrier in each aperture. Small solder spheres (58--58) are located in a plurality of dimples (56--56) of a planar plate (40) in arrays that are substantially the same as a plurality of bonding pad arrays (18--18) on the bottom surface of a plurality of chip carriers. A vacuum is applied to the holder (22) to hold the chip carriers (10--10) in the apertures (28--28) as the holder rotates to place the bonding pads (18--18) in contact with the solder spheres (68--68). The solder spheres (58--58) are reflowed by applying heat to form a solder "bump" (68) on each pad (18). The chip carriers (10--10) are then cooled and loaded into a plurality of the tubular members (39--39).

Abstract: A technique for dynamically changing from a full, rotating spool (18) of lightguide fiber (10) to an empty spool (19) while maintaining a substantially constant feed velocity is described. The fiber (10) is moved along a tapered transition section (40 or 52) having a continually decreasing cross-sectional diameter as the spools (18 and 19) and the transition section (40 or 52) rotate at the same velocity. The rotational velocity of the spools and the transition section are increased as the fiber is wound therealong. The fiber is transferred from the transition section onto the empty spool.

Abstract: A spring clip (30) for holding chip carriers in place on a pallet (20) serves to urge a case (12) seated in each of a plurality of pallet cavities (22) against an underlying lid (14) therein during fabrication of the chip carrier (10). The spring clip (30) comprises a central shaft (32) which extends vertically through the center of a metal plate (31). The plate (31) has a plurality of radially outstretched resilient arms (36), each sloping downwardly from a separate side thereof and having an upturned end (37). The lower end (38) of the shaft (32) is sized for lockable engagement with a corresponding one of a plurality of receiving passages (24) in the pallet (20). Each passage (24) is surrounded by a group of pallet cavities (22). When the first end of each shaft (32) of the spring clip (30) is lockably engaged with the pallet (20), the chip carriers (10) are held on the pallet (20) by the ends (37) of the arms (36).

Abstract: A technique for dynamically transferring a lightguide fiber (10) from a full spool (18) to an empty spool (19) as both spools rotate at the same velocity and the input velocity of the fiber is constant. The lightguide fiber (10) is wound onto the rotating spool (18) in such a manner as to form a package of wound material having a conically tapered section (52) when full. The fiber (10) is then wound along the tapered section (52) as the velocity of the spools (18 and 19) are increased. When the fiber (10) is at the diameter of the tapered section (52) which is equal to the diameter of the empty spool, it is transferred to the empty spool without any substantial loss of fiber spooling control.

Abstract: A plurality of rows of leads (6,7) extending from a connector (5) are inserted into vias (32--32) in a circuit board (24) having components thereon. A plurality of slots (84--84) in a comb (60) are aligned with the vias (32--32) and the connector (5) moved towards the comb to position the leads (6,7) therein. A downward force is applied to the connector (5) causing the leads (6,7) to slide along the slots (84--84) and into the vias (32--32). The comb (60) is arcuately moved a short distance to disengage the leads (6,7) therefrom and then moved upward, away from the board (24). The board (24) with the connector (5) thereon is removed. The comb (60) is then moved back to the vertical position to receive the leads of the next connector (5) to be inserted in the vias (32--32).

Abstract: An apparatus for applying a coating on a lightguide fiber (60). The apparatus is comprised of a container (10) having the coating die (18) in the bottom portion thereof and a plurality of separating means (26--26) therein which divides the container into an upper chamber (12), a lower chamber (16) and at least one chamber (14) intermediate to the upper and lower chambers. Each separating means (26) is sealed to the inner surface of the container (10) at the outer edge portion and has a small, centrally located aperture (28) which is vertically aligned with the apertures in the other separating means and the coating die (18). Additionally, a means is provided for directing coating material (40), under pressure, into the lower chamber (16).