Metal Planarization Process Which Retains Alignment Targets
Original Publication Date: 1987-Jul-01
Included in the Prior Art Database: 2005-Feb-01
By means of the scheme described in this article it is possible to planarize an opaque metal film covering semiconductor substrate topological features without the loss of targets essential for proper alignment of the next masks for photoresist patterns. Some semiconductor processing technologies require that wafer/substrate structures be made planar at various stages of build in order to minimize process tolerances and to improve uniformity. While it is possible to create alignment masks on the resultant surfaces with a blockout mask and etch, the procedure is costly and relies on gross manual alignment of the blockout mask.