POROUS FILM FOR PREPREG AND PREPREG FOR CIRCUIT BOARD

摘要

PROBLEM TO BE SOLVED: To obtain both a porous film for a prepreg capable of excellently being subjected to a laser via processing of fine pitch, having excellent heat resistance and capable of being suitably impregnated with a thermosetting resin and a prepreg for a circuit board using the same. SOLUTION: This porous film for a prepreg comprises an open cell porous film of a polyimide-based resin, has >=0.05μm average particle diameter on both obverse and reverse sides and 30-98% porosity. This prepreg for a circuit board comprises a semicured material of a thermosetting resin impregnated into the pores of the porous film.