| 摘要 |
PROBLEM TO BE SOLVED: To provide a method of cleaning which can easily remove Cu atoms existing inside of a silicon wafer and which is simple in construction of its apparatus, by immersing a silicon wafer in a cleaning solution that is composed of sulfuric acid, hydrogen peroxide and water, and heated to a specified temperature. SOLUTION: A silicon wafer is cleaned by immersing in a cleaning solution, which is composed of sulfuric acid (H2SO4), aqueous solution of hydrogen peroxide (H2O2) and water, and heated to a specified temperature ranging from 80 deg.C to 200 deg.C, for a specified duration of time. The cleaning solution is preferably composed of 80-88 weight % of sulfuric acid, 6.0-2.5 weight % of hydrogen peroxide, and the rest of water. The ratio between sulfuric acid and aqueous solution of hydrogen peroxide, both of which are commercial products of unified concentration, is preferably between 3:1-5:1, by considering the cleaning effect on copper (Cu) and stability at the high temperature of sulfuric acid and of aqueous solution of hydrogen peroxide. If the cleaning temperature is lower than 80 deg.C, it is not possible to diffuse Cu atoms, which have diffused in the silicon wafer to contaminate the silicon wafer, to the surface of the silicon wafer adequately, and to remove Cu atoms existing inside of a silicon wafer.
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