Synthesis of Fluorinated Alkali-Soluble Photosensitive Resin and Study on the Application in Solder Resist

As a critical material for packaging substrates, solder resist (SR) is essential for the development of advanced packaging. However, the increasing demands for high performance and miniaturization of electronic devices have raised higher requirements for SR. In this study, a novel fluorinated alkali-soluble photosensitive resin (PE-1) was synthesized through molecular structure design. Meanwhile, in order to overcome the thermomechanical limitations, a series of composite FSR with different resin ratios were prepared by introducing rigid alkali-soluble bisphenol A-type phenolic epoxy acrylate. The effects of different resin ratios on the comprehensive performance of FSR were systematically investigated. The results indicate that when the PE-1 content is 40wt%, FSR-0.4 exhibits a dielectric constant as low as 3.11 (5 GHz), a glass transition temperature as high as 176.05 °C, and an increased water contact angle of 99.8 °. Additionally, FSR-0.4 demonstrates a low coefficient of thermal expansion (32.35 ppm/K), a high 5% thermal decomposition temperature (337.66 °C), tensile strength (62.11 MPa) and elongation at break (3.46%), with a pencil hardness of 5 H and excellent photolithographic resolution (40 μm). This study developed FSR with excellent comprehensive properties, meeting the requirements of advanced electronic manufacturing for low dielectric constant, high thermal resistance and high processing precision. This study offered new design strategies and theoretical foundations for the development of next generation high-performance solder resist materials.