Patent ID: 7642198
Filing Date: 2010-01-05
Classification: G01N,H01L

Abstract:
1. A method for evaluating crystal defects of a silicon wafer comprising: evaluating crystal defects of a silicon wafer by selectively etching a surface of the silicon wafer by immersing the wafer in an etching solution and observing etch pits, which originated from crystal defects, formed on the etched surface of the wafer, wherein the silicon wafer of which crystal defects are evaluated has low electrical resistivity of 1 Ω·cm or less, and the etching solution is a mixture of hydrofluoric acid, nitric acid, acetic acid and water further including iodine or iodide, the etching solution having a volume ratio of hydrofluoric acid:nitric acid:acetic acid:water of 1:13-17:4-8: 4-8 and includes iodine or iodide in a range from 0.01 g to 0.09 g per 1 liter of total liquid volume of the etching solution to decrease the etching rate of the etching solution, and the etching solution is adjusted to have an etching rate of 100 nm/min or less for the silicon wafer.