Cost-of-ownership comparison of single-wafer processes for stripping copper pillar bump photomasks

摘要

Akrion Systems and A* Star IME scientists have effectively collaborated to apply proprietary single-wafer process technology to reduce the cost-per-wafer of the thick photoresist stripping process. The results apply to chemically amplified, positive tone resist masks, and negative tone photoresist masks, in the 20 μm to 100 μm range. In the case of the 40 μm mask, where new and old processes were compared, the new process combining megasonics and heated N_2 spray for chemical feed, provides a cost per wafer savings of 22%.