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Electrical Testing of Glass Metallized Modules

IP.com Disclosure Number: IPCOM000077489D
Original Publication Date: 1972-Aug-01
Included in the Prior Art Database: 2005-Feb-25
Document File: 3 page(s) / 32K

Publishing Venue

IBM

Related People

Cahill, JG: AUTHOR [+2]

Abstract

A method has been devised for electrically testing glass modules that have metallized paths on a surface, as well as through the module from one surface to an opposite surface.

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Electrical Testing of Glass Metallized Modules

A method has been devised for electrically testing glass modules that have metallized paths on a surface, as well as through the module from one surface to an opposite surface.

The module 2 to be tested, as seen in the figure, comprises a 2''X2'' ceramic plate. On the bottom side 4, a small number of relatively large contacts, about 400 of them, protrude from that side. Two of the contacts are labelled A and D. On the other or top side 6 a much larger number of smaller contacts (about 6000) protrude, only two of which are marked 8 and 10. Most of the top contacts are only connected to another top contact and normally do not have any direct connection to any of the bottom contacts.

The top surface 6 is covered with a photoconductive layer 12 which can be applied by spraying, evaporation, by use of a slurry or a powder, or any other suitable technique. If a slurry or a photoconductive powder in a volatile binder is used, such photoconductive layer is evenly distributed by putting a MYLAR* diaphragm 14 over the top surface, and pressurizing the diaphragm until it touches the top contacts so as to avoid deposition of a photoconductive layer on top of the contacts. The module is placed in a test jig and the bottom contacts are contacted in a normal fashion.

Conductive paths between top contacts are created by selective illumination of the top surface, either through MYLAR foil or with the latter removed. Current circuits, such as path ABCD, are formed that begin and end at a bottom contact but which incorporate one or more top-top circuits, thus allowing for the testing of all possible circuits. After electrical tests have been completed, the photoconductor is removed by any suitable chemical etchant. The above-noted technique has a number of advantages:

1) The photoconductive film does not have to be contacted in any other...