Enhancing the Performance of Epoxy-Based Solder Resist via Imide Ring Incorporation and Acid Value Regulation

Solder resist (SR), a critical material for printed circuit boards, plays an essential role in advanced packaging technologies. In this study, the imide ring was incorporated into the molecular structure of the SR matrix resin, and the comprehensive performance of SR was significantly improved by utilizing the superior chemical properties of the imide ring. Additionally, by adjusting the acid value of the resin, we effectively controlled both the hydrogen bond index of the resin and the cross-linking density of SR, allowing for further optimization of SR properties. A systematic analysis of SR properties revealed that SR-3 exhibited a peel strength of up to 0.43 N/mm, tensile strength of 81.77 MPa, elongation at break of 6.3%, and a coefficient of thermal expansion 1 (CTE1) as low as 23.25 ppm/K, along with excellent acid and alkali resistance, hydrophobicity, thermal stability. These experimental results provide a deep insight into the logical relationship between the structure of the base resin and the comprehensive performance of SR, which is important for understanding the impact of base resin structure on SR performance and offers a strategy for developing high-performance SR. Furthermore, comparative analysis with the commercial product POR demonstrated that SR-3 exhibits significant application potential in advanced packaging.