| 摘要 |
PROBLEM TO BE SOLVED: To obtain desired thickness of a wafer with good reproducibility by a method, wherein an impurity layer which is formed inside the wafer by ion-implanting impurities from the rear side of the wafer is used as an etching stopper, and silicon on the rear of the wafer is wet-etched. SOLUTION: Ions are implanted from the rear side of a wafer 1, and an impurity layer 2 is formed inside the wafer 1. Then, the surface and the side face of the wafer 1 are coated with a photoresist 3. After that, only the rear side of the wafer 1 is immersed in a mixed acid (a mixed solution of hydrofluoric acid and nitric acid) to be etched. At this time, silicon on the rear side of the wafer 1 is dissolved by the mixed acid, but the impurity layer 2 inside the wafer 1 is not dissolved so as to function as an etching stopper. The rear side of the wafer 1 is etched in the depthwise position of the impurity layer 2. As a result, the magnitude of acceleration energy at implanting of the ions is adjusted, and the impurity layer 2 is formed in a proper depthwise position, and the desired thickness of the wafer can be obtained.
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