Patent ID: 8124223

Claim:
An electronic substrate material comprising: a polyimide adhesive based composition comprising: (i.) a polyimide base polymer having a glass transition temperature between 150 and 300° C., the base polymer being present in a range from 25 to 95 weight percent of the total weight of the polyimide adhesive based composition, the polyimide base polymer having a coefficient of thermal expansion (“CTE”) above 50 ppm/° C., (ii.) an aramid micro fiber filler having an average diameter between 0.002 and 2.000 microns and an average length of between 10 1 and 10 7 nanometers, the aramid micro fiber filler being present in an amount between 5 and 75 weight percent of the polyimide based adhesive material, wherein the polyimide adhesive based composition provides an overall coefficient of thermal expansion (“CTE”) equal to or below 50 ppm/° C., wherein the electronic substrate material is a circuit coverlay layer, a dielectric layer in a flexible polyimide metal-clad laminate, a dielectric layer in a circuit board, or a dielectric layer in a semiconductor device package.