| 摘要 |
PROBLEM TO BE SOLVED: To provide sufficient enough irregularities in a uniform thickness on the back surface of a wafer for discriminating between the front and back surfaces, without giving the influence of the back surface on the front surface by cutting a semiconductor ingot into a wafer, planarizing the cut face thereof, etching it with alkali, polishing it with a double-sided polisher, and cleaning it. SOLUTION: A semiconductor ingot is cut into a wafer 1, its periphery 13 is chamfered, and the front and back cut faces 11, 12 of the wafer are planarized by lapping, resulting in machining strains 14 of the front and back surfaces. The wafer 1 is then etched with alkali to remove the strains 14, resulting in an irregularity 15 of about 2.0μm in P-V value. The front and back surfaces of the etched wafer is polished, e.g. by about 10μm and 0.2μm, using a double-sided polisher and then the wafer is cleaned, thus making a mirror front surface with irregularities 15a remaining on the back surface. |
