Browse Prior Art Database

Chip Contact Assembly

IP.com Disclosure Number: IPCOM000042871D
Original Publication Date: 1984-Jun-01
Included in the Prior Art Database: 2005-Feb-04
Document File: 3 page(s) / 61K

Publishing Venue

IBM

Related People

Lusk, SD: AUTHOR

Abstract

Conventional chip contacting probes are cantilevered pins, for example which are permanently fastened in a ring-like structure with the number of pins equaling the number of pads to be contacted on the semiconductor chip. A problem which has frequently occurred with these contact assemblies is that the probes tend to bend or break and require relatively frequent cleaning in order to insure good electrical contact with the semiconductor pads. The assemblies are frequently custom-made by vendors by soldering the pins with their cantilevered suspensions in place in a ring about a center. Such assemblies are expensive to procure, and the turn-around time for obtaining replacement assemblies can be significant. These problems are solved by the improved chip contact assembly invention disclosed in Figs. 1 through 3.

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Chip Contact Assembly

Conventional chip contacting probes are cantilevered pins, for example which are permanently fastened in a ring-like structure with the number of pins equaling the number of pads to be contacted on the semiconductor chip. A problem which has frequently occurred with these contact assemblies is that the probes tend to bend or break and require relatively frequent cleaning in order to insure good electrical contact with the semiconductor pads. The assemblies are frequently custom-made by vendors by soldering the pins with their cantilevered suspensions in place in a ring about a center. Such assemblies are expensive to procure, and the turn-around time for obtaining replacement assemblies can be significant. These problems are solved by the improved chip contact assembly invention disclosed in Figs. 1 through 3. The improved chip contact assembly finds specific application in the test system disclosed in [*]. Within that system, the improved chip contact assembly provides an easy method for changing the type of part number which is to be tested, since the improved chip contact assembly is of modular construction which enables the easy substitution of an assembly for a first part number in exchange for an assembly for a second part number. Referring now to Fig. 1, an insulating card 50, which may be composed of a plastic such as PLEXIGLAS* or other suitable insulating material, has deposited thereon a pattern of conductive printed circuit wires 52 which start at a contacting edge indicated by the numeral 68 and terminate at a recess 54 which is shown in better view in Fig. 2. Fig. 2 is a cross-sectional view of the card 50. The printed circuit wire 52 passes into the recessed area 54 where it comes into close proximity with the hole 56 which is drilled diagonally through the card 50. The tip 62 of the single contacting wire 58 passes through the hole 56 and out to the underside of the card 50 where it will be able to contact a respective pad on the device 106 to be tested. The upper portion 60 of the wire 58 electrically contacts the portion of the printed circuit wire 52 which is within the recessed region 54. The wire 58 should have a relatively stiff mechanical characteristic somewhat similar to the probe tips conventionally used in integrated circuit contacting assemblies. When wires 58 in an array have been inserted through their respective holes 56 in the card 50 so as to have a contacting pattern which conforms with the pattern of pads on the semiconductor chip to be tested, then the cover plate 64 may be fastened down on top of the upper portions 60 of the wires 58 and compressed by means of the screws 66 fastening to the threaded portions of the card 50, so as to clamp the wires 58 into place. This construction for the improved chip contact assembly, shown in Fig. 1, enables the easy replacement of defective contact wires 58 when they bend, break, incur burrs, or become fouled with pad material. It shou...