Next-Generation Dry Film Photoresist for Advanced IC Substrate Applications

The continuous demands of advanced electronics devices with increasing functionality and performances has driven the IC substrate industry to increase the density of interconnects and to develop new package substrates with different structures. In order to scale down of copper traces, the advance of photolithography including the development of high-resolution exposure machine and dry film photoresists (DFRs) is highly required. In this paper, we report our research efforts on the development of next-generation DFRs used in direct imaging (DI) exposure machines for advanced IC substrate applications. The DFR product was developed through adopting a hydrophobic binder with a novel binder component and an optimized photoinitiator package to enable excellent resolution, adhesion, and chemical resistance against acid cleaner prior to plating processes. The newly developed DFRs can achieve line and space (L/S) of 5/5um with 25um thickness under direct imaging (DI) exposure systems.