Abstract:
The disclosure is directed to process and apparatus for the removal, site preparation, and replacement of any single connector pin contained within a sizeable array of closely spaced very small connector pins on an electronic packaging structure (substrate or module) without causing deleterious metallurgical effects either to the remaining pins or the ceramic substrate.
Abstract:
A process for improving the solderability of a layer of a silver frit burnt onto a glass pane and a current connecting element wherein a layer of enamel is disposed and the surface of soldering and the glass pane. According to the process the surface is treated with a fluorine containing etching agent prior to soldering. The fluorine containing etching agent may be an aqueous solution of an acid fluoride, such as ammonium hydrogen fluoride or alkali hydrogen fluoride.
Abstract:
Defective chips are removed from a substrate package. The package is cleaned. Replacement chips with solder bearing elements are replaced in the position(s) of the defective chip(s). Silicon chips are less damaged by heating with light wavelengths substantially shorter than infrared radiation, when the radiation is directed upon the upper chip surface and the lower chip surface carries circuitry and solder balls. Radiation is absorbed by the upper chip surface and converted there directly to heat, protecting the circuitry below. An argon-ion laser beam confined to a given chip is directed upon the upper surface of the chip to be soldered in place. A thin laser beam can be scanned under computer control across a chip to heat the areas of a chip above solder balls. Automatic temperature control of the chip can be provided by a heat detector or chip condition detector and a program controller in a feedback loop controlling laser power.
Abstract:
A wafer of semiconductor material having a plurality of units defined on its face is subdivided by treating the wafer, on its back or reverse side, in the kerf regions between the units, where division of the units is desired, such that the material of the wafer in the treated kerf regions is converted to a material having a breaking strength lower than the breaking strength of the semiconductor material.
Abstract:
A method for the low cost production of printed circuits with both soldered-in component leads and welded wire connections, which includes applying a sheet of highly weldable material such as stainless steel to an insulative board, plating a layer of highly solderable material such as copper over the stainless steel, applying a first resist pattern and then a first etchant such as ferric chloride that etches both copper and stainless steel to form a predetermined printed circuit pattern, and then applying a second resist pattern and a second etchant such as chromic acid which etches only the copper to leave exposed regions of the stainless steel. Components can be wave soldered in place, and the solder will not adhere to the stainless steel so that wires can later be welded to the exposed stainless steel weld regions. More uniform welding can be obtained by applying an underlayer of copper to the insulative substrate under the stainless steel layer, so that there is a low resistance path to all weld regions.
Abstract:
A bonding apparatus and method for simultaneously bonding the leads of a beam-leaded device uniformly to conductive pads on a substrate. A continuous strip of metal consisting of a plurality of heat and pressure transmitting members is intermittently fed to a rotatable bonding head having a plurality of bonding tools. Each transmitting member is adapted to be interposed between the bonding tool and the leads of the beam-leaded device to evenly distribute and transmit bonding forces to such leads to effect uniform and simultaneous bonding thereof to their connections. A crimping device coacts with the bonding tools to partially deform a transmitting member about its respective tool prior to bonding.
Abstract:
1,007,459. Welding by pressure. WESTERN ELECTRIC CO. Inc. Aug. 21, 1962 [Aug. 30, 1961 (2)], No. 32018/62. Heading B3R. [Also in Divisions H1 and H4] A device for banding a fine wire to a part comprises an elongated member having at one end a banding head for transmitting pressure to the wire, the head having a groove with non-concave inner faces to engage the wire initially along lines of contact only. A device for bonding a very fine gold wire 12, Fig. 1, to an aluminium stripe 13 sputtered on a semiconductive body 14 comprises a steel member 16 having a pair of parallel tungsten cylinders 19 welded to the lower surface thereof to form a groove for the wire passed from a guide 22. The member 16 is mounted in a chuck 27, Fig. 4, on an arm 32 carrying a transducer mounted by wedges 37 in a carrier 36 and supplied with current at a frequency of 20-60 kc. per sec. Clamps 38, 39 on the carrier 36 are pivoted to a cradle 43 and the pressure exerted on the work by the member 16 is determined by a knob 76 carrying a pin 77 which may be spring urged into one of a number of slots in a plate 75, the knob carrying a cam operating on a sleeve between which and the carrier 36 is arranged a coil spring. In operation the semi-conductor body 14 soldered etc. to a header 86 is held by placing header leads 87 into apertures 88 in a support disc 89 on a fixture 92 adjustable for height and transverse location, the member 16 is brought adjacent the stripe on the semiconductor and the knob 76 is rotated to provide a force of about ten grams on the work. The transducer is energized to scrub the wire against the stripe resulting in bonding. The wire and/ or the stripe may be heated. In a modification the elongated member of glass, sapphire, quartz, diamond etc. has a V-shaped groove on a flat side, a chamfered edge and a flat portion for a round wire passed through a guide. In a further modification the elongated member has a passageway 187, Fig. 12, therethrough and is tapered at its lower end to provide a flat surface 193 to which are welded parallel tungsten cylinders forming a groove for the wire 12 passing down through the passage way 187. A shearing device 213 cuts the wire projecting from the elongated member and bends it through 90 degrees into the groove. This member is used in thermo-compression bonding also. The apparatus may be used to bond wires of copper etc. to conductive, semi-conductive or non- conductive parts.