Halogen-Free Epoxy with Enhanced Corrosion Resistance for Microelectronics Packaging via γ S_N2 Nucleophilic Substitution

Bisphenol A diglycidyl ether (DGEBA) is an essential epoxy resin in the microelectronics industry. However, circuit corrosion caused by hydrolyzable chlorine─a persistent issue associated with DGEBA─poses significant challenges in this field. In this study, we present a novel strategy for producing halogen-free DGEBA with high purity (up to 99%) and isolated yield (up to 94%) by utilizing glycidyl sulfonates as the starting material. A distinctive γ SN2 nucleophilic substitution pathway between glycidyl sulfonates and phenolic compounds effectively suppresses the formation of ring-opening byproducts and oligomers, as demonstrated through model reactions and kinetic studies. The scalability and versatility of our method are validated by its straightforward synthesis process and expanded substrate scope. Finally, the halogen-free DGEBA exhibits noncorrosive properties when employed as a matrix resin for prepreg and underfill applications. Our research underscores the potential of glycidyl sulfonate as a viable alternative to epichlorohydrin in large-scale epoxy production for electronics.