Process to manufacture tight tolerance embedded elements for printed circuit boards

摘要

A process for forming printed circuit substrates incorporating impedance elements in which a pattern of impedance elements and a conductor pattern are incorporated on an insulating support. The process involves depositing a layer of an impedance material (4) on a first surface of a sheet of an electrically highly conductive material (2) and attaching a second surface of the sheet of highly conductive material (2) to a support (8). Then one applies a layer of a photoresist material (6) onto the layer of impedance material (4) with imagewise exposure and development. After etching away the portion of the impedance layer material (4) underlying the removed nonimage areas of the photoresist material (6), a pattern of impedance elements (4) remain on the sheet of highly conductive material (2). Thus printed circuit board with impedance elements can be manufactured to a high degree of electrical tolerance.