Hello, I am doing Electroless Cu plating on SiO2 substrate. I found the solution can deposit Cu film on Si but not SiO2. I tried to use different self-assembly monolayer to modify the surface, but still not succeed. One thing I am concerned about the SiO2 substrate cleaned with Pirana solution has contact angle of 45 degree which is different from other reported contact angle (nearly Zero degree). I don't know how the difference comes. Appreciate if you share your experience and suggestion. Regards Cassie