High-Adhesion Epoxy-Based Solder Resist Dry Film for Integrated Circuits Enhanced by 2,2-Bis(hydroxymethyl)propionic Acid

The increasing demand for high performance and miniaturization of electronic devices creates an urgent need for solder resist materials with excellent comprehensive properties. We report a photothermal dual-curable solder resist dry film (SRF) material. The preparation method and performance characteristics of epoxy-based SRF modified with acrylic acid, 2,2-bis(hydroxymethyl)propionic acid (DMPA), and cis -1,2,3,6-tetrahydrophthalic anhydride were systematically studied and also compared with the commercially available product. With the introduction of DMPA, SRF-2 exhibits excellent adhesion, and the peel strength between SRF-2 and copper increased from 0.33 to 0.45 N/mm, a 36% increase; this improvement was achieved by introducing a certain proportion of hydroxyl groups into the epoxy resin molecular chain. Additionally, its dielectric constant decreased from 3.73 to 3.38 and the room-temperature modulus increased from 5.1 to 5.4 GPa. Moreover, SRF-2 exhibits excellent thermal stability, hydrophobicity, and photolithographic performance, indicating potential application prospects in integrated circuits.