Circuit board and overlay.

摘要

A polyimide film (1) is used to make a printed circuit board or overlay by applying to it a first thermosetting adhesive layer 2 of thickness at most 0.5 mu m, and a second thermosetting adhesive layer (3). If the product is a board, a metal foil (4) is applied to the free surface of the layer (3); if an overlay a release paper (5) is applied.