Additive metalization using photosensitive polymer as RIE mask and part of composite insulator

摘要

The surface of an integrated circuit, which uses reactive ion etching to pattern metal interconnection, is protected with two insulating layers on the surface. The first layer is a conventional silicon dioxide. The second layer is a photosensitive polymer which is the same as the material used for subsequent metalization of interconnection using the reactive ion etching technique. When the second layer is used, the reactive ion etching cannot attack the silicon dioxide. A trench can be cut through the two insulating layers, using a window in the photosensitive polymer as a mask, to serve as a via hole for metal to contact the substrate