Patent ID: 8822242

Claim:
A method for determining or monitoring the amount of metal contamination imparted into semiconductor wafers during a process, the method comprising: exposing a silicon-on-insulator structure other than the semiconductor wafers to a processing step, the silicon-on-insulator structure comprising a handle wafer, a silicon layer, and a dielectric layer between the handle wafer and the silicon layer, the structure having a front surface on the silicon layer, the processing step imparting metal contamination in the silicon layer; thermally annealing the silicon-on-insulator structure to cause metal contaminants in the silicon layer to dissolve; cooling the silicon-on-insulator structure to form metal precipitates in the silicon layer; detecting the metal precipitates in the silicon layer by contacting the surface of the silicon layer with an etchant, the etchant: (1) comprising hydrogen fluoride with the concentration of hydrogen fluoride in the etchant being less than about 5% by weight; or (2) being a Secco etchant; and verifying whether the amount of metal contamination imparted into semiconductor wafers other than the silicon-on-insulator structure is acceptable, the semiconductor wafers not being silicon-on-insulator structures.