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Browse Prior Art Database

Elimination of Mask Substrate Defects

IP.com Disclosure Number: IPCOM000047844D
Original Publication Date: 1983-Dec-01
Included in the Prior Art Database: 2005-Feb-08
Document File: 1 page(s) / 11K

Publishing Venue

IBM

Related People

West, RL: AUTHOR

Abstract

Small voids in the chromium film of the incoming mask substrate result in mask defects and a high repair incidence. This procedure would repair those pinholes. 1. If the substrate is not already coated with positive photoresist, apply a positive photoresist. A very high quality resist film is not necessary. 2. Expose the photoresist film through the back of the substrate, thus exposing only the areas above the pinholes (blanket exposure of reverse side). 3. Develop the photoresist, and evaporate a chromium film onto the surface of the developed resist. Chromium will deposit on the substrate where the resist was exposed, covering the pinholes. 4. Dissolve the undeveloped photoresist with a suitable solvent, "lifting off" chrome which lies on resist surfaces.

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Elimination of Mask Substrate Defects

Small voids in the chromium film of the incoming mask substrate result in mask defects and a high repair incidence. This procedure would repair those pinholes. 1. If the substrate is not already coated with positive photoresist, apply a positive photoresist. A very high

quality resist film is not necessary. 2. Expose the photoresist film through the back of the substrate, thus exposing only the areas above the pinholes

(blanket exposure of reverse side). 3. Develop the photoresist, and evaporate a chromium film onto the surface of the developed resist. Chromium

will deposit on the substrate where the resist was exposed,

covering the pinholes. 4. Dissolve the undeveloped photoresist with a suitable solvent, "lifting off" chrome which lies on resist surfaces.

If mask-clear defects result from poor adhesion of chrome to glass, rather than from voids in the coating, an ultrasonic cleaning operation, carried out before coating with photoresist, will tend to scrub off the loosely attached chrome, allowing the process described above to automatically find and repair those areas as well.

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