Patent ID: 6794031
Filing Date: 2004-09-21
Classification: H05K,Y10T

Abstract:
A cover-lay film for high-density mounting comprising a heat-resistant film and an adhesive layer, wherein said adhesive layer comprises an epoxy resin composition containing (a) an epoxy resin, (b) a curing agent, c) a phenolic hydroxyl-containing polyamide-poly(butadiene-acrylonitrile) copolymer, and (d) an ion capturing agent and having a glass transition temperature of 80Â° C. or higher after cure, said heat-resistant film is a polyimide film which mainly comprises a polyimide containing a 3,3â€²,4,4â€²-biphenyl-tetracarboxylic acid component and a p-phenylenediamine component and has a coefficient of linear thermal expansion of 10 to 25 ppm/Â°C. in a temperature range of 50 to 200Â° C. in both machine and transverse directions and a tensile modulus of 450 to 1100 kgf/mm2 in both machine and transverse directions, said cover-lay film has such electrical reliability that the surface insulation resistance measured at 121Â° C. and 85% RH with an applied voltage of 50 V using a comb pattern of IPC-B-25 from level B up shows no reduction for more than 200 hours, and wherein said ion capturing agent (d) is a hydrotalcite compound represented by formula:MgxAly(OH)2x+3yâˆ’2z(CO3)zÂ·mH2O wherein x, y, and z each represent a number satisfying the relationships: 0