Patent ID: 10477700

Abstract:
A method for manufacturing a printed circuit board, comprising in order steps (i) providing a non-conductive substrate having on a surface copper circuitry with a copper surface, wherein said surface is chemically treated by (a) oxidation and subsequent reduction reaction and/or (b) organic compound attached to said surface, a permanent, non-conductive, not fully polymerized cover layer covering at least partially said surface, (ii) thermally treating the substrate with the cover layer at temperature from 140° C. to 250° C. in atmosphere containing molecular oxygen at 100000 ppm or less, based on the total volume of the atmosphere, wherein a substrate with a permanent, non-conductive cover layer is obtained, with the provisos that (ii) is after (i) but before any metal or metal alloy is deposited onto the cover layer, and that in (ii) the cover layer is fully polymerized in one thermal treating step, if the cover layer is a solder mask.