PFAS-free I-line strong photoacid generator for positive-tone and negative-tone thick-film photoresists

In this study, we present the development of PFAS-free AZ® FZero 3DT positive photoresist and AZ® FZero NX-3015 negative photoresist. These novel photoresists were enabled by the utilization of a newly developed PFAS-free M PAG (photoacid generator). Both AZ® FZero 3DT and AZ® FZero NX-3015 photoresists have exhibited comparable lithography performance to their PFAS-containing comparative examples on both Silicon (Si) and Copper (Cu) substrates. Furthermore, the newly developed PFAS-free M PAG has displayed good stability on Cu substrates, outperforming the commercial oxime sulfonate PAG. This stability is particularly crucial for the successful application of photoresists in the fabrication of re-distribution layers (RDL) in advanced semiconductor packaging.