Method for manufacturing a printed circuit board

A method for manufacturing a printed circuit board, the method comprising in this order the steps:

• (i) providing a non-conductive substrate having on at least one surface
• a copper circuitry with a copper surface, wherein the copper surface is
• chemically treated by (a) an oxidation and subsequent reduction reaction and/or (b) an organic compound attached to the copper surface,
• a permanent, non-conductive, not fully polymerized cover layer covering at least partially said copper surface,
• (ii) thermally treating the substrate with the permanent, non-conductive, not fully polymerized cover layer at a temperature in the range from 140° C. to 250° C. in an atmosphere, which contains molecular oxygen in an amount of 100000 ppm or less, based on the total volume of the atmosphere, such that a substrate with a permanent, non-conductive cover layer is obtained, the cover layer being more polymerized compared to step (i),
• with the proviso:
• that step (ii) is carried out after step (i) but before any metal or metal alloy is deposited onto the permanent, non-conductive, not fully polymerized cover layer, and
• that in step (ii) the permanent, non-conductive, not fully polymerized cover layer is fully polymerized in solely one single thermal treating step, if the cover layer is a solder mask.