Browse Prior Art Database

Fabrication of Multiprobe Miniature Electrical Connector

IP.com Disclosure Number: IPCOM000085963D
Original Publication Date: 1976-Jun-01
Included in the Prior Art Database: 2005-Mar-03
Document File: 3 page(s) / 45K

Publishing Venue

IBM

Related People

Anacker, W: AUTHOR [+5]

Abstract

An electrical connector is described which consists of two silicon wafers bonded together having cavities filled with a metal which is liquid at or above a desired temperature, and supports a high density of electrically conducting pins which are individually insulated from each other. This connector is useful in testing and in packaging electronic circuits by providing a means for the input and output of signals to individual elements of the circuits.

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Fabrication of Multiprobe Miniature Electrical Connector

An electrical connector is described which consists of two silicon wafers bonded together having cavities filled with a metal which is liquid at or above a desired temperature, and supports a high density of electrically conducting pins which are individually insulated from each other. This connector is useful in testing and in packaging electronic circuits by providing a means for the input and output of signals to individual elements of the circuits.

Such a structure has been fabricated using materials and techniques which are well known in silicon technology. A brief description of the method used to fabricate such a structure in single-crystal silicon is given below. Method of Fabrication

A fabrication technique similar to that shown in IBM Technical Disclosure Bulletin, Vol.17, No.11, April 1975, pages 3450-3452, entitled "Fabrication Technique to Control the Size of Silicon Nozzles" can be utilized to form holes of the desired shape in silicon wafers. Briefly, two silicon wafers 1.25'' diam, (100) orientation, 8 mils thick are thermally oxidized and arrays of holes 16 x 16 mil/2/ are etched in the oxide photolithographically to expose the silicon substrate. The latter is etched in an anisotropic etching solution consisting of ethylene-diamine, pyrocatechol and water.

The resulting holes or cavities are truncated square pyramids bounded on 4 sides by the slowest etching (111) planes. The openings formed on the opposite side of each wafer are also square, with dimensions 5 x 5 mil/2/. The oxide is then stripped from the surface of the wafers. The wafers are then oxidized in order to form a uniform SiO(2) film on the wafer faces as well as the walls inside the cavities.

The oxide film is doped with phosphorus to form a phosphosilicate glass (PSG) layer over the SiO(2) film. The overall thickness is approximately 1.2 micron. Two wafers are clamped together in a quartz fixture, front faces touching in such a way that the large square bases of each truncated pyramid are aligned as shown in Fig. 1. By applying pressure between the wafers and heating to about 1100 degrees C in vacuum, the PSG layers fuse, thus bonding wafers 1 together. The resulting structure contains a large array of octagonal insulated cavities 2 having a shape as shown in Fig. 2 with entrance and exit holes 5 x 5 mil/2/. The bond could also be formed with more common adhesives at room temperature.

The bonded pair of wafers 1 thus...