Browse Prior Art Database

Method of Producing Contact Metallizations

IP.com Disclosure Number: IPCOM000049175D
Original Publication Date: 1982-May-01
Included in the Prior Art Database: 2005-Feb-09
Document File: 2 page(s) / 35K

Publishing Venue

IBM

Related People

Hafner, B: AUTHOR [+4]

Abstract

By means of this method, platinum silicide is formed in the contact holes of the silicon wafers. Subsequently, a chromium layer is deposited on the platinum silicide areas by electroless plating. By means of a lift-off process, an aluminum/copper metallization is applied to the chromium layer.

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Method of Producing Contact Metallizations

By means of this method, platinum silicide is formed in the contact holes of the silicon wafers. Subsequently, a chromium layer is deposited on the platinum silicide areas by electroless plating. By means of a lift-off process, an aluminum/copper metallization is applied to the chromium layer.

On a semiconductor wafer 1, layer 2 of SiO(2) and layer 3 of Si(3)N(4) are formed, and contact openings for emitter, base, collector, Schottky diodes, resistors, and the like are generated. By vapor depositing platinum and sintering at about 35O degrees C, platinum silicide areas 4 are formed in the contact holes. Non-sintered platinum is removed by aqua regia. For the subsequent metallization, a lift-off mask is formed which consists of release layer 5, photoresist layer 6 and SiN layer 7 with openings 8 above platinum silicide areas
4. As the previously used vapor deposition of chromium had to be effected through a very high channel in openings 8 of the lift-off mask, there was the risk of the peripheral areas of platinum silicide layer 4 being inadequately chromium coated. During the subsequent vapor deposition of aluminum/copper, this led to undesirable contact between aluminum and platinum silicide.

By means of this improved method, chromium layer 9 is applied to the platinum silicide areas 4 by electroless plating. For this purpose, the silicon wafers are immersed in an electroless chromium bath. The thickness of the chromium...