Abstract:
An electroless metal plating process, particularly for use in plating through-holes in printed circuit substrates, (14) and more particularly for additively depositing copper metal on through-hole surfaces, in which the substrate is at least intermittently subjected to vibrating motion in contact with the electroless depositing bath, (12) and an electroless metal depositing apparatus for carrying out the process.
Abstract:
Multilayer printed circuits, and methods for their fabrication, are provided, characterized in that the conductive circuitry of the circuitry innerlayers is built up from electroless copper, and the surfaces of the electroless copper which confront the sandwiching pre-preg resin layers are provided with a tin coating to promote adhesion of the electroless copper to the pre-preg resin layers. The invention is particularly suitable for preparing multilayer circuits having buried through-holes.