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Browse Prior Art Database

High Resolution Photomask

IP.com Disclosure Number: IPCOM000073505D
Original Publication Date: 1970-Dec-01
Included in the Prior Art Database: 2005-Feb-22
Document File: 2 page(s) / 32K

Publishing Venue

IBM

Related People

Atwood, BC: AUTHOR

Abstract

This method provides high contrast, high resolution, projection exposed photoresist masks by the use of an in situ produced contact mask to eliminate degradation of the projection mask image due to diffraction.

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High Resolution Photomask

This method provides high contrast, high resolution, projection exposed photoresist masks by the use of an in situ produced contact mask to eliminate degradation of the projection mask image due to diffraction.

A substrate 1 upon which a photoresist pattern is to be developed is first coated with a conventional photoresist 2. A high contrast, high resolution photoemulsion 3, sensitive to a different light frequency than the photoresist, is coated over the undeveloped photoresist as shown in A. During a first exposure step, photoemulsion 3 is projection exposed to produce a negative latent image 4 of the desired mask pattern, as shown in B. Exposed emulsion 3 is developed to form an opaque contact mask for the subsequent exposing of photoresist 2 resulting in a latent image 5, as shown in C. Thereafter, photoemulsion 3 is removed and photoresist 2 is developed to form the desired mask in the conventional manner.

The method may also be used in contact mask exposure applications to reduce the effects of variations in light intensity across the surface of the contact mask or to reduce diffraction problems caused by incomplete mask contact with the photoresist.

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