Fluorine-free i-line thick film photoresist for advanced semiconductor packaging

Thick film photoresists play a crucial role in enabling high-density interconnects and robust structural features in advanced semiconductor packaging. These photoresists are integral to processes such as, Redistribution Layer (RDL), interconnect pillar bump, and Through-Silicon Via (TSV) formation in Wafer-Level Packaging (WLP). As the demand for smaller, more powerful electronic products continue to grow, as well as sustainable/responsible practices in semiconductor manufacturing, the development of advanced thick film photoresists remains a critical area of research and innovation. A novel fluorine-free i-line positive-tone thick film photoresist for the fabrication of Redistribution Layers (RDL) and copper pillar bumps in advanced wafer-level packaging has been developed. This innovative positive-tone photoresist, AZ® FZeroTM 3000, formulated with our in-house developed fluorine-free photoacid generator (M PAG), achieves a high resolution for the applications of 30μm, 75μm, and 100μm film thicknesses by utilizing a low NA (0.16) stepper. The performance of AZ® FZeroTM 3000 is comparable to that of traditional PFAS PAG-containing thick film resists.