Modified Wet Etch Process for Polyimide
Original Publication Date: 1986-Feb-01
Included in the Prior Art Database: 2005-Mar-08
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.