Patent ID: 7699997

Claim:
A method of reclaiming a used silicon wafer having copper penetrated into the interior of the wafer from a semiconductor manufacturing process, comprising: in the following order, a film removal process including removing at least one of a metal film, a metal silicide film, a metal oxide film, and a metal nitride film from the used silicon wafer to form a silicon wafer having a silicon surface; contacting the silicon surface of the silicon wafer with at least one of an SC1 and an SC2 liquid to diffuse copper from the interior of the silicon wafer to the silicon surface of the silicon wafer; a heating/removal process to remove a portion of the silicon surface of the silicon wafer; a polishing process; and a cleaning process to form a reclaimed silicon wafer having a silicon surface and a concentration of copper of less than 2×10 12 atom/cm 3 ; wherein the heating/removal process comprises (i) heating the silicon wafer at 150-300° C. for 20 minutes to 5 hours and (ii) a chemical process that comprises removing a surface part of the silicon wafer by etching the top surface of the silicon wafer with a solution comprising one or more of an alkaline hydroxide and an alkaline carbonate to a depth of about 1 μm.