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Fabrication of Iron Oxide Masks

IP.com Disclosure Number: IPCOM000074529D
Original Publication Date: 1971-May-01
Included in the Prior Art Database: 2005-Feb-23
Document File: 1 page(s) / 11K

Publishing Venue

IBM

Related People

Horvat, JG: AUTHOR [+3]

Abstract

Semitransparent photolithographic masks are formed by depositing a thin film of iron, etching the mask pattern and then oxidizing the iron to iron oxide.

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Fabrication of Iron Oxide Masks

Semitransparent photolithographic masks are formed by depositing a thin film of iron, etching the mask pattern and then oxidizing the iron to iron oxide.

A thin film of iron is deposited by electron beam evaporation onto a transparent substrate such as borosilicate or quartz glass. The film is coated with resist, the resist is imaged, and a pattern is etched into the iron using a dilute mineral acid: For example, a mixture of 0.1 ml of concentrated hydrochloric acid and 0.1 ml of nitric acid in 1000 mls of deionized water. The resist is removed and the iron pattern is oxidized by an RF plasma or by heating in air at about 500 degrees C for 15 minutes to form a durable semitransparent iron oxide mask. The semitransparent mask can be visibly aligned but is substantially opaque to exposing ultraviolet radiation.

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