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Developing Patterns in Polyimide Films

IP.com Disclosure Number: IPCOM000091733D
Original Publication Date: 1968-May-01
Included in the Prior Art Database: 2005-Mar-05
Document File: 1 page(s) / 12K

Publishing Venue

IBM

Related People

Anderson, NC: AUTHOR

Abstract

Patterns desired in polyimide films are obtained by using positive photoresists in an etching process which utilizes the fact that partially cured polyimides are soluble in strongly basic solutions. A partially cured polyimide film is coated with a positive photoresist. The latter is exposed to ultraviolet light using an appropriate mask. The exposed photoresist is developed with a basic developer, 0.3 N. NaOH solution, for a time sufficient to remove the exposed resist and also to dissolve the partially cured polyimide film in the area underlying the exposed photoresist. The partially cured polyimide film covered by unexposed photoresist remains undissolved. There is negligible undercutting. The resolution obtained is comparable to that obtained in etching metallic films using photoresist.

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Developing Patterns in Polyimide Films

Patterns desired in polyimide films are obtained by using positive photoresists in an etching process which utilizes the fact that partially cured polyimides are soluble in strongly basic solutions. A partially cured polyimide film is coated with a positive photoresist. The latter is exposed to ultraviolet light using an appropriate mask. The exposed photoresist is developed with a basic developer, 0.3 N. NaOH solution, for a time sufficient to remove the exposed resist and also to dissolve the partially cured polyimide film in the area underlying the exposed photoresist. The partially cured polyimide film covered by unexposed photoresist remains undissolved. There is negligible undercutting. The resolution obtained is comparable to that obtained in etching metallic films using photoresist. The process is used either for obtaining patterns in partially cured polyimide films overlying fully cured polyimide films or for partially cured polyimide films overlying other substrate materials.

In one example, 5.5 mil lines on 7 mil centers are obtained in a layer of 1.5 micron thick partially cured polyimide, PYRALIN* RC-5081, on a 6 micron fully cured polyimide film on a rigid substrate. The underlying polyimide film is cured for fourteen hours at 200 degrees C and coated, by spinning, with the 1.5 micron thick film of polyimide. The second layer of polyimide is partially cured by baking for one hour at 150 degrees C in air. A coat...