METHOD OF MAKING A PRINTED CIRCUIT BOARD

摘要

A method is provided herein for making a printed circuit board. The method includes the first step of forming conduc- tive circuit elements on two opposed faces of a paper phenolic-containing substrate. The substrate and the conductive circuit elements are then coated with a desensi- tising material. Holes are formed through the substrate, each hole passing through a circuit element on each of the opposed faces of the board. The board is then treated to render the substrate which is exposed in the holes receptive to the action of a metallic plating solution. The de-sensitising material is then removed. An acid-resist mask is presented onto both faces of the board, the mask leaving exposed only a small area of the board surrounding each hole therethrough. Finally, the board is treated with an electroless nickel- plating solution to deposit nickel in the holes to the desired thickness to provide an electrical connection through each hole between two opposed conductive circuit elements.