| 摘要 |
PURPOSE: To manufacture a semiconductor wafer containing less impurities by damaging the first and second surfaces of the wafer and having the impurities in damaged areas gettered by heating the wafer for a prescribed period of time at a prescribed temperature, and then removing the gettered impurities by removing the damaged areas. CONSTITUTION: Mechanical damages are caused to surfaces 11 of a semiconductor wafer 10. Bulk defects and metallic impurities enter the wafer during crystal growth and the following wafer shaping work as shown by lines 12 and the impurities 12 are distributed throughout the wafer 10. The wafer is heat-treated for about one hour at about 1,000 deg.C. The temperature is raised linearly, from about 800 deg.C and lowered linearly to 800 deg.C, so as to prevent the warping of the wafer. Then the thickness of the wafer 10 is made uniform by mechanically lapping both surfaces of the wafer 10, and the surface flatness of the wafer 10 is improved. The broken lines 14 indicate the removing parts of the wafer 10 and the thickness of the removed parts of the wafer 10 is typically about 20μm. The lapping work removes the impurities gettered on the damaged surfaces 11.
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