Development of low-dielectric polyimide composites based on perfluorosilane coupling agent sealed mesoporous silica

Abstract

The exponential expansion of the telecommunications electronics and industry has driven a surge in demand for low dielectric thin film materials, which are extensively employed as interlayer dielectrics in electronic packaging, as sealing materials, and as substrates for flexible copper-clad laminates. In this paper, mesoporous silica with hollow nanopore structure (MCM-41), sealed with perfluorosilane coupling agent, was introduced into polyimide (PI) matrix by in-situ polymerization to prepare modified MCM-41/PI composite films. The longer fluorine-containing branched chain in 1H,1H,2H,2H-perfluorodecyltrimethoxysilane (THFS) brings better interfacial compatibility and dispersion compared to 1H,1H,2H,2H-perfluorooctyltrimethoxysilane (TTFS). As a result, the PI composite film containing 3 wt% of MCM@THFS (MCM@THFS/PI-3) shows the excellent comprehensive performance among all films, with its dielectric constant decreasing to 2.14@1 MHz, its coefficient of thermal expansion (CTE) value decreasing to 50.78 ppm/K, and its water contact angle improving to 85.43°. Obviously, MCM@THFS/PI-3 shows great potential for application in the field of low dielectric.