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Etching Wafer Backside With Minimal Contamination

IP.com Disclosure Number: IPCOM000074822D
Original Publication Date: 1971-Jun-01
Included in the Prior Art Database: 2005-Feb-23
Document File: 1 page(s) / 11K

Publishing Venue

IBM

Related People

Petrak, JR: AUTHOR [+2]

Abstract

In the processing of silicon wafers, it is often desirable to strip the oxide from the back of the wafer without etching or contaminating the front side. This result is achieved by floating the wafer front-side down in a container of high-purity water and placing one or more drops of hydrofluoric acid on the wafer back. When all the oxide is removed (indicated by a hydrophobic appearance), the wafer may be immersed and then transferred to another container for rinsing in high-purity water. Etching of the wafer front side is completely avoided, since any acid reaching the wafer edge is rapidly diluted. Exposure only to high-purity water ensures that the process does not contaminate the wafer front side.

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Etching Wafer Backside With Minimal Contamination

In the processing of silicon wafers, it is often desirable to strip the oxide from the back of the wafer without etching or contaminating the front side. This result is achieved by floating the wafer front-side down in a container of high-purity water and placing one or more drops of hydrofluoric acid on the wafer back. When all the oxide is removed (indicated by a hydrophobic appearance), the wafer may be immersed and then transferred to another container for rinsing in high-purity water. Etching of the wafer front side is completely avoided, since any acid reaching the wafer edge is rapidly diluted. Exposure only to high-purity water ensures that the process does not contaminate the wafer front side.

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