E-Beam Registration Mark Integrity
Original Publication Date: 1984-Jun-01
Included in the Prior Art Database: 2005-Feb-04
One four-level metal personalization process, called VWP (Vertical Wiring Process), requires seven levels of exposure by electron beam tools, including K, L1, L2, M, V1, V2 and X levels. A major problem for E-beam registration occurs at the L2 level and subsequent levels because planarization processes are required at the L3 and V3 etchback levels, which tend to form and/or remove marks created by topography and on which E-beam registration depends. A traditional solution for registration for planar processes has been to include an extra lithography level to clean out the registration mark area, including: 1. a resist coat and bake, 2. exposure of a blockout of the registration mark area, 3. development, 4. an etch to clean out the quartz, and 5. a resist strip.