Patent US 6,965,136

An embodiment of the invention is a method to reduce light induced corrosion and re-deposition of a metal, 8, (such as copper) that is used to make the interconnect wiring during the semiconductor manufacturing process. The light induced corrosion and re-deposition is caused by the exposure of a P-N junction to light, causing a photovoltaic effect. A photon-blocking layer, 13, is used in the invention to reduce the amount of exposure of the P-N junction to light. The photon blocking layer, 13, of the invention may be a direct band-gap material with a band-gap energy that is less than the lower edge of the energy spectrum of a typical light source used in the semiconductor manufacturing facility (typically less than 1.7 eV).