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Masking for SiO(2) Etching

IP.com Disclosure Number: IPCOM000086063D
Original Publication Date: 1976-Jul-01
Included in the Prior Art Database: 2005-Mar-03
Document File: 1 page(s) / 11K

Publishing Venue

IBM

Related People

Beyer, KD: AUTHOR [+2]

Abstract

It is often required to have silicon dioxide, SiO(2), etched from half of one side of a silicon wafer while retaining SiO(2) on the other half and on the other side of that wafer.

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Masking for SiO(2) Etching

It is often required to have silicon dioxide, SiO(2), etched from half of one side of a silicon wafer while retaining SiO(2) on the other half and on the other side of that wafer.

Masking for the subsequent etching step is accomplished by cracking a like wafer in half, putting a drop of water on the SiO(2) wafer and placing the half- wafer thereon as a mask. Capillary action will keep the half-wafer in place against the SiO(2).

The wafer is placed, masked side down, on the neck of a 1000 ml wide- mouth bottle containing a small amount of concentrated 49% hydrofluoric, HF. The HF vapor will etch the SiO(2) on the unmasked half and will not disturb the SiO(2) on the other half or on the front side. The SiO(2) remains clean and the wafer can easily be rinsed and dried. The half-wafer used as a mask slips off under water and it can be used over again as a mask.

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