Browse Prior Art Database

In Situ of Plated Contacts

IP.com Disclosure Number: IPCOM000077350D
Original Publication Date: 1972-Jul-01
Included in the Prior Art Database: 2005-Feb-25
Document File: 2 page(s) / 36K

Publishing Venue

IBM

Related People

Seiden, PE: AUTHOR

Abstract

In the plating of contacts on multilevel metallized modules, the conventional procedure is to place a photoresist mask on the module to be plated and holes for the plated contacts are then provided by known techniques.

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In Situ of Plated Contacts

In the plating of contacts on multilevel metallized modules, the conventional procedure is to place a photoresist mask on the module to be plated and holes for the plated contacts are then provided by known techniques.

According to this technique, after the holes have been provided, metal is then applied such as by evaporation in a pattern as shown in the figure, the metal being applied to the "top" surface (the surface opposite to that in contact with the module of the plating mask).

In the described technique, there is no direct metallic contact between the metallic strips at the start of the plating process whereby resistance, R is relatively high. As the plated contacts reach the surface, a metal short develops between the conductor strips on the opposite sides of a hole resulting from the metal which is in such hole. Consequently, the value of R drops. When all of the holes in a line are filled with metal, the resistance drops to a low value.

Although the described technique does not completely localize any defect, it does indicate the line in which a defect exists, i.e., square root of n contacts must be examined for a defect rather than all n, the total number of contacts for the module. If desired, the number of contacts to be searched over can be further decreased with more intricate interconnection arrangements.

For the technique to be efficacious, the resistivity of the plating bath should be much greater than that of the met...