Porous, heat resistant insulating substrates for use in printed circuit boards, printed circuit boards utilizing the same and method of manufacturing insulating substrates and printed circuit boards

摘要

The insulating substrate comprises an insulating sheet made of cellulose material and a prepreg impregnated with a thermosetting resin and bonded to at least one surface of the insulating substrate. A printed circuit board is prepared by forming electric conductors arranged in a predetermined circuit pattern on the surface of the prepreg.