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Exposure Procedure for Positive Photoresists

IP.com Disclosure Number: IPCOM000089788D
Original Publication Date: 1977-Dec-01
Included in the Prior Art Database: 2005-Mar-05
Document File: 1 page(s) / 11K

Publishing Venue

IBM

Related People

Pacansky, J: AUTHOR

Abstract

Photoresists which consist of a photoactive compound (a diazo oxide) mixed into a phenolic resin are normally positive working. That is, exposure to light renders the resist more soluble to a base developer, whereas in the areas not exposed to light, the resist becomes less soluble by perhaps azo dye formation induced by the base developer.

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Exposure Procedure for Positive Photoresists

Photoresists which consist of a photoactive compound (a diazo oxide) mixed into a phenolic resin are normally positive working. That is, exposure to light renders the resist more soluble to a base developer, whereas in the areas not exposed to light, the resist becomes less soluble by perhaps azo dye formation induced by the base developer.

We propose here a method in which no azo coupling is involved, and the resist is still positive working.

A thin film of a diazo-phenolin resin photoresist is coated on a silicon wafer and irradiated through a mask in air. Subsequently, the mask is removed, and a flood exposure is performed in vacuum. (The exposure in air produces carboxylic acid which is soluble in base developer. The exposure in vacuum produces a cross linked phenyl ester that is much less soluble in base developer.) The image is developed in an aqueous base solution. The result is that the areas exposed in air are washed away while the other areas are not.

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