Abstract:
A process to pretreat copper surfaces for tight bonding to organic substrates as those found in multilayer printed circuit boards includes first treating the copper with a solution containing hydrogen peroxide, and at least one acid, and at least one nitrogen-containing five-member heterocyclic compound which does not contain sulfur, selenium or tellurium atoms in the heterocycle. Thereafter the copper surfaces are brought into contact with a second solution containing at least one adhesion-promoting compound from the group consisting of sufinic acid, selinic acid, telluric acid, and heterocyclic compounds that contain at least one sulfur, and/or selenium and/or tellurium atom in the heterocycie and also sulfonium, selenonium and telluronium salts.