In super trace metal analyzing of the silicon wafer surface the etching manner

摘要

PURPOSE: To prevent contamination from chemical and to decrease contamination from a container by performing decomposition with the mixed vapor of nitric acid and hydrofluoric acid in a specified ratio, and analyzing liquid of dew condensation. ;CONSTITUTION: Aqueous solution containing nitric acid of 14.3-14.9mol/l and hydrofluoric acid of 1.1-0.2mol/l is heated. The very minute amount of metal in the layer down to the depth of 1μm from the oxide film of the surface of a wafer and a silicon-bulk surface layer is dissolved with the generated vapor and the liquid of dew condensation generated by the cooling at the surface of a silicon wafer. The liquid of dew condensation is analyzed. In order to perform the ultramicroanalysis of the metal on the surface of the wafer 1, the weight of the wafer 1 is measured. The amount of the liquid of the dew condensation is obtained based on the difference between the weight and the weight before the processing and the specific gravity of the liquid of the dew condensation, which is obtained beforehand. Then, the liquid of dew condensation is recovered with a micropipette and measured with a frameless atomic absorbing analyzer as a sample. The weight of the silicon wafer after drying is measured as required, and the etching amount is obtained.;COPYRIGHT: (C)1994,JPO&Japio