CPC H01L 21/304 (2013.01) [H01L 21/02013 (2013.01); H01L 21/78 (2013.01); H01L 2224/85207 (2013.01)] | 8 Claims |
1. A protective sheet laid on a surface of a wafer, the protective sheet comprising:
a first sheet that is thermocompression-bonded directly to the surface of the wafer by heating, wherein the first sheet is a polypropylene sheet;
a second sheet that is laid on the first sheet and has fluidity due to the heating; and
a third sheet that is laid on the second sheet and is allowed to keep flatness even with the heating;
wherein the first sheet, the second sheet and the third sheet are thermocompression bonded to become a three layer protective sheet.
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