Multi-Step Etching of Dissimilar Materials Achieving Selectivity and Slope Control
Original Publication Date: 1985-Dec-01
Included in the Prior Art Database: 2005-Feb-19
Layers of dissimilar materials can be anisotropically etched to produce features having controlled sidewall slopes and retaining selectivity when needed. This is done by using a multi-step etching process, i.e., changing process parameters for successive, small etch depth increments in a reactive ion etch system. In the fabrication of integrated circuits, it is frequently necessary to etch features through multiple layers of dissimilar materials which have been deposited on a semiconductor substrate. Slope control of feature edges must be maintained, and the ability to stop etching at selected material interfaces is required. A process achieving these goals starts after photoresist has been applied over the deposited film layers on a semiconductor substrate.