Abstract: A process and composition are disclosed for directly electrometallizing a non-conductive substrate such as the non conductive surfaces of a circuit board and to directly effect through hole plating and/or form circuits on the boards without employing an electroless metal coating.A process and composition is also described for depositing metals on a non-conductive substrate by using the reductive capacity of hydrogen in the presence of a metal catalyst on the substrate. The metal catalyst is combined with hydrogen that is generated electrolytically from a protic bath. The metal catalyst combined with hydrogen is contacted with a metal salt. The metal salt may be combined with the protic bath so that the hydrogen that is generated electrolytically combines with the metal catalyst and the metal salt is converted to a metal coating on the substrate.

Abstract: A novel immersion tin composition is disclosed containing both thiourea compounds and urea compounds. A method for improving the adhesion of printed circuit boards to one another in a multilayer board and for minimizing or eliminating smear in a multilayer board is also disclosed comprising coating the metal layers of the individual circuit boards with an immersion tin coating prior to laminating them to form a multilayer board.

Abstract: A novel immersion tin composition is disclosed containing both thiourea compounds and urea compounds. A method for improving the adhesion of printed circuit boards to one another in a multilayer board and for minimizing or eliminating smear in a multilayer board is also disclosed comprising coating the metal layers of the individual circuit boards with an immersion tin coating prior to laminating them to form a multilayer board.

Abstract: A process is disclosed for manufacturing a circuit board having a metal layer in which a portion of the metal layer is removed by etching. A novel etch resist immersion tin composition is selectively applied to the metal layer to leave areas of coated and uncoated metal followed by etching the metal not coated with the resist. The immersion tin composition is applied as a substantially pore free coating at thicknesses of from about 0.08 to about 0.175 microns. The novel immersion tin composition contains a tin salt and both thiourea compounds and urea compounds.