Method of Improving the Adhesion of Copper Conductors on Plastic Laminates in Printed Circuit Boards
Original Publication Date: 1984-Oct-01
Included in the Prior Art Database: 2005-Feb-05
During the production of signal cores for printed circuit boards, a photoresist foil is directly laminated to an epoxy resin laminate that has been dendritically roughened by etching a laminated copper foil. After the photoresist foil has been exposed according to the desired conductor pattern and developed, a thin chromium layer and subsequently a copper layer are applied in a vacuum sputter system. The chromium/copper layer is removed from the exposed photoresist regions, and, in an additive step, copper is non-defectively grown in the conductor channels. The signal core is completed after removal of the photoresist. In the example disclosed herein, four dyed epoxy resin-based prepregs are laminated with sacrificial copper foils at about 190ŒC.