Adhesive enabling technology for directly plating copper onto glass/ceramic substrates

This study showcases that metal oxide adhesion promoters (MOAP) can function as strong adhesive layers between plated Cu and glass/ceramic. In this new approach a 10-200 nm thick metal oxide layer is deposited by a modified sol gel process followed by sintering. This enables reliable electroless and electrolytic metallization of glass or ceramic substrates. With the new approach, Cu can be plated on a variety of glass types. Substrate roughness appears to have only limited impact. The new approach also can be extended to ceramics such as Al₂O₃ and BaTiO₃. Cu film of over 50 μm thickness can be deposited without delamination. Adhesion of 15 μm thick Cu layers as measured by 90° peel strength tests can achieve well above 5 N/cm. The plated layer stands up well to solder reflow shock (260°C) and HAST without significant loss of adhesion. Good coverage of the MOAP layer and excellent copper adhesion inside the via holes of patterned substrates have been also demonstrated. There is no indication of blockages of holes with diameters >20 μm by the process.