Fabrication of Circuit Lines on Printed Circuit Boards
Original Publication Date: 1984-May-01
Included in the Prior Art Database: 2005-Feb-03
Copper current-carrying lines are often used on polymer boards to produce electrical circuits. In the art, a three-layer, peel-apart composite is often used to provide these lines. The composite is bonded to the polymer sheet by an adhesive layer, and comprises a first thin layer of copper, an intermediate layer of a material such as chromium oxide, and a thick overlying copper layer. The thick copper layer and the chromium oxide layer are peeled away to leave the thin copper layer, which can be used as a plating base for the formation of the current-carrying lines. In order to overcome the need for this peel-apart composite, a process is described in which a thin copper layer is evaporated or sputtered onto the polymer sheet.