Abstract: A printed circuit board is formed from a metal-clad substrate by applying a solvent-free, non-dryable ink in a predetermined pattern on the substrate, dusting powdered resin over the surface, removing any resin powder not retained by the ink from the surface, heating the substrate having the ink powder thereon to a temperature so as to fuse the powdered resin to form a strippable resist, etching the uncoated portion of the metal laminate and stripping the resist subsequent to etching.

Abstract: Herein disclosed is a noncontact, nondestructive method for monitoring the quality of a high energy weld, e.g., laser beam weld. In accordance with the proposed method, an acoustic sensor (32) is positioned at a distance from the welding zone (34) and picks up airborne acoustic emission signals (33) associated with the laser welding process. These acoustic signals, propagating through the air space between the welding zone (34) and the sensor (32), are detected and analyzed (36,37) to determine the quality of the weld (FIG. 3).

Abstract: An automatic pull tester and an acoustic emission system are herein combined to analyze the failure modes of lead frames bonded to integrated circuits. By using a discriminant analysis technique, a specific failure mode can be determined in real-time by first measuring up to five variables during the pulling operation. The five variables that may be measured comprise acoustic emission signals of a first amplitude (AE1), acoustic emission signals of a second amplitude (AE2), the time elapsed until failure (.DELTA.t), the number (n) of acoustic emission bursts above a first threshold, to the peak pulling force at failure (L.sub.max). Next, the variables measured are incorporated into a plurality of predetermined functions, each function corresponding to one failure mode (FM1 to FM5). The failure mode of the bond is determined by selecting the function having the highest value (FIG. 4).

Abstract: A reactant deposition torch (10) has a plurality of concentric glass tubes (16, 18, 20, 24 and 26). Various gases pass through the tubes (18, 20, 24 and 26) while particle producing reactants pass through the inner tube (16). The concentricity of the tubes is accurately maintained by a plurality of precision machined splines located on the outer periphery of the inner and intermediate tubes (16, 18, 20 and 24). Additionally, the inner tube (16) is movable in the axial direction during the deposition process to controllably alter the amount of reactant to be deposited.

Abstract: An apparatus for substantially eliminating excessive edge growth in liquid phase epitaxy utilizing a substrate carrier 11 and a source material carrier 13 slidable over the substrate carrier 11 including a well 24 around a recess 14 in the substrate carrier 11 wherein the substrate 16 is held. The well 24 contains a material therein which reduces the heat loss from the edges of the substrate 16 held in the recess 14 thereby reducing excessive epitaxial growth around the edges of the substrate 16.

Abstract: The attachment of leadless chip carriers to printed wiring boards by means of soldering techniques must provide for a spacing between the chip carrier and the board. Such spacing is required for cleaning the area under the chip carrier, protecting the underlying circuitry, and accounting for stresses which may develop due to thermal mismatch between the chip carrier and the board, and to board flexure. Herein disclosed is a lead (15) for semiconductor chip carriers comprising an elongated body of high melting point electrically conductive material, e.g., solder material. Also disclosed is a method for casting such a solder lead, and a method for attaching a plurality of cast solder leads (38) to a leadless chip carrier (20).

Abstract: In the manufacture of integrated circuits, it is often necessary to prepare dielectrically-isolated single-crystal silicon regions to be used as substrates in which various circuit elements may be formed. These regions or substrates are formed by attaching a single-crystal silicon wafer (1) having a dielectrically-coated surface (2) to a second single-crystal silicon wafer (3) by means of an intermediate metallic layer (4) positioned therebetween. Using a heating process, e.g., a thermomigration process also referred to as temperature gradient zone-melting (TGZM) technique, the metallic layer (4) is removed through the second silicon wafer (3). This method substantially eliminates any bending or warpage of the dielectrically-isolated substrate (FIG. 1).

Abstract: A coating material is applied to drawn lightguide fiber in a manner which substantially prevents the inclusion of bubbles and which causes the fiber to be disposed substantially concentrically within the coating layer. The lightguide fiber is advanced through a continuum of coating material, which extends from a free surface of a reservoir and through first and second dies that are arranged in tandem, at a velocity which causes air to be entrained in the coating material. A pressure gradient is established between portions of the first die adjacent to its exit orifice. The first die communicates with the reservoir and is spaced from the second die to provide a chamber which communicates with a pressurized supply of the coating material.

Abstract: A method of electrolessly plating a substrate having a rubber-modified epoxy surface includes the steps of preheating the substrate and while still warm, sputter etching at least 50A. from its surface. The substrate is then vacuum metalized with an adhesion promoting metal film, coated with a catalytic layer and a metal is electrolessly deposited thereover.

Abstract: Articles (12) are loaded onto a movable article holder such as pedestals (18) mounted to a rotary table (20). The table is indexed to advance the articles (12) first to a centering station (41) and then to a work station (49) which may be, for example, a lead frame bonder. At the centering station (41) a typical centering mechanism (22) urges the articles to a predetermined center location. While the centering mechanism may be adjusted to and fixedly located in a position to center the articles (12) to a theoretical center removed by precisely one step or a multiple thereof from the bonding position, the centering station (41) provides for tangentially shifting the theoretical center with respect to the table (20). Any shift of said theoretical center is made to offset an anticipated error of alignment of the articles, even though such error may be unique to each of the pedestal positions.

Abstract: In the growth of gadolinium gallium garnet monocrystals, a crucible is charged with a preformed body (65) of oxide powders to form a melt. In preparation therefor, the oxide powders are formulated into a typical particulate material (16) which is compacted into a body (65) having a desired size and shape. For holding material (16), there is provided a pouch (38) of a first size having elastic walls expandable to a second size, larger than body (65). The pouch (38) is disposed within a chamber (36) having inside walls conforming to the desired shape of the body (65) but of the second size. An open neck (42) of the pouch (38) extends through and is sealed to an opening (60) in chamber (36). Then a vacuum is drawn between the pouch (38) and chamber (36) to expand pouch (38) to said shape and second size formed by the chamber walls. As the particulate material (16) is introduced into the expanded pouch (38), such material conforms to the shape and second size of such expanded pouch.

Abstract: An enclosed electrical device (42) includes an electrical circuit (50) having elements (48-68) which lie substantially in and along a plane (115). A member (70) is applied to a one side and a member (85) is applied to another side of the circuit (50) for at least partially enclosing the same. Conductors (48) and (49) of circuit (50) are fixedly penetrated, preferably by pins (74) which are fixedly engaged to enclosure members (70) and (85). Such engagement is advantageously provided by making the pins (74) an integral part of member (70), for example by including pins (74) in a premolded member (70). Such engagement is also advantageously provided by making pin-engaging sockets (94) an integral part of member (85), also for example by including the sockets (94) in a premolded member (85). By a preferred friction fit of pins (74) and sockets (94), the enclosure members (70) and (85 ) and circuit elements (48-68) are sufficiently fixed relative to one another to resist forces applied thereto in service.

Abstract: A method is disclosed for determining the index of refraction profile of a stepped or graded index type optical fiber having a core encased within a surrounding cladding. An interferogram is formed with a beam of radiant energy passed transversely through the optical fiber. Fringe line shift is measured at a series of points corresponding to a series of mutually parallel ray chord paths extending through the core at mutually diverse minimum radial distances from the core axis. That portion of the measured fringe line shift attributable to discrete differences in indices of refraction of cylindrical core ring portions of thicknesses defined by successive minimum radial distances in the series of ray paths and that of the cladding is sequentially calculated from the outermost core ring portion inwardly towards the core center.

Abstract: Undeposited reactants (i.e., soot) passing through a glass substrate tube (12), during the fabrication of a lightguide perform by the Modified Chemical Vapor Deposition (MCVD) process, flow into a reactant exhaust system (50) and are carried therethrough by a uniformly flowing reactant-free gas. The reactants pass through an exhaust tube (52), a reactant collection chamber (54), through a pressure control apparatus (56;114) and into a gas scrubber. The pressure within the exhaust system (50) is maintained substantially constant during the MCVD process by continuously monitoring the pressure therein and adjusting the pressure control apparatus (56;114) accordingly. Additionally, a continuous, uniform flow of soot-free gas is directed into the exhaust system to assist in the removal of the undeposited reactants therefrom.

Abstract: A method of forming a colloidal wetting sensitizer is disclosed. The method comprises combining a stannous species and a cupric species in an aqueous medium maintained at a pH of between 0.4 and 1.5.

Abstract: Paramagnetic articles such as a stem (14) and an armature (17) are placed into mutual coextensive alignment with a gap (19) of a predetermined width between adjacent portions of such articles. To repetitively establish the predetermined gap between successive groups of such articles, a first of such articles is guided tangentially into a magnetic field. A resulting force on such article (14) draws the article against a first stop surface. The article becomes magnetically polarized, such that when the second article, such as the armature (17) is guided into coextensive alignment with the first article, the second article becomes attracted to the first article to be drawn against a stop surface opposite to and spaced from the first stop surface by a dimension equal to the predetermined gap width.

Abstract: A wire wrapping tool (10) includes a gun (20), a bit (24) for cutting, stripping and wrapping a wire (21), a sleeve (25) for receiving the bit and a wire softening device (26). The device (26) includes a pair of opposed rollers (28,30) for softening the wire (21) pulled therethrough.

Abstract: A method of removing contaminants from the surface is disclosed. The method comprises coating the surface with a surface active agent having a first surface energy and into which the contaminants are combined, applying thereover a higher surface energy colloidal sol and then allowing sufficient time for the first surface energy material with the contaminants combined therewith to migrate through the colloidal sol so as to remove the contaminants from the immediate vicinity of the substrate surface. The surface may then be treated by exposing it to an acid or base to remove the migrated surfactant layer thus removing the trace of contaminants.

Abstract: A hydrostatic extrusion die includes a nose-cone section (21) of a high toughness tool steel and a mating rear section (22) of a high compressive strength material such as carbide. During extrusion, inwardly directed radial forces (F.sub.r ') are developed in the rear section which exactly compensates for the outwardly directed radial forces (F.sub.o) developed at the throat of the die.

Abstract: A filter (21) for removing flux from a hot heat transfer liquid-flux mixture. The heat transfers liquid-flux mixture is directed into a chamber (41) having a plurality of spaced, hollow members (64--64) through which a coolant passes. Upon being cooled the flux deposits on the surface of the members (64--64). The liquid, with substantial portions of the flux removed therefrom, then leaves the filter (21).