DRY FILM AND MULTILAYER PRINTED WIRING BOARD

摘要

A dry film includes a supporting base film and a thin membrane of a thermosetting resin composition. The thin membrane of the thermosetting resin composition is formed on the supporting base film. The thermosetting resin composition includes a liquid epoxy resin, a solid epoxy resin, a semisolid epoxy resin, an epoxy curing agent and a filler. The liquid epoxy resin is liquid at 20° C. and has at least two epoxy groups in a molecule. The solid epoxy resin is solid at 40° C. and has at least three epoxy groups in a molecule. The semisolid epoxy resin is solid at 20° C. and liquid at 40° C. and has at least two epoxy groups in a molecule. A ratio of mass of the liquid epoxy resin to a sum of mass of the solid epoxy resin and mass of the semisolid epoxy resin is about 1:1 to about 1:10 A ratio of the mass of the solid epoxy resin to the mass of the semisolid epoxy resin is about 1:0.5 to about 1:2.