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Modified Wet Etch Process for Polyimide

IP.com Disclosure Number: IPCOM000060041D
Original Publication Date: 1986-Feb-01
Included in the Prior Art Database: 2005-Mar-08
Document File: 1 page(s) / 11K

Publishing Venue

IBM

Related People

Chaker, M: AUTHOR [+4]

Abstract

By means of a two-step etching process, clean openings are etched in a layer of polyamic-acid which have sidewalls with shallow slope and no over-hanging material at the top edges of the holes. After a final cure, a layer of polyimide is formed having openings of suitable shape for formation of metal lines which are reliably continuous over the edges of the openings and reliably contact conductive material exposed at the bottom of the openings. Starting with a substantially uncured layer of a polyamic-acid- containing polymer resin on the surface of a substrate, an etch mask is formed using conventional photoresist processing to define the location of the desired openings. In a first etch step, the substrate is exposed to an aqueous solution of 0.

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Modified Wet Etch Process for Polyimide

By means of a two-step etching process, clean openings are etched in a layer of polyamic-acid which have sidewalls with shallow slope and no over-hanging material at the top edges of the holes. After a final cure, a layer of polyimide is formed having openings of suitable shape for formation of metal lines which are reliably continuous over the edges of the openings and reliably contact conductive material exposed at the bottom of the openings. Starting with a substantially uncured layer of a polyamic-acid- containing polymer resin on the surface of a substrate, an etch mask is formed using conventional photoresist processing to define the location of the desired openings. In a first etch step, the substrate is exposed to an aqueous solution of 0.268 molar sodium silicate for a sufficient time to etch through the thickness of the polyamic-acid layer at the position of the desired openings. The etch mask layer is then removed by a conventional resist stripper. The substrate is then heated to result in partial imidization of the polyamic-acid layer in order to reduce the solubility of the polyamic-acid layer in aqueous alkali reagents. In a second etch step, the substrate is exposed to an aqueous solution comprised of 5% by weight tetraalkylammonium hydroxide for a sufficient period of time to remove unimidized polyamide-acid from within the previously etched openings and from the surface of the partially imidized polyamic-ac...