Double-disc grinding machine, static pressure pad, and double-disc grinding method using the same for semiconductor wafer

摘要

The present invention is a static pressure pad for supporting both sides of a raw wafer without contact by a static pressure of a fluid supplied to the both sides of the raw wafer in a double-disc grinding machine for a semiconductor wafer, wherein in patterns of lands to be banks of surrounding pockets formed on a surface side of supporting the raw wafer of the static pressure pad, an outer circumferential land pattern required to support the raw wafer is a concentric circle with respect to a rotation center of the raw wafer, and a land pattern inside the outer circumferential land pattern is a non-concentric circle with respect to the rotation center of the raw wafer and asymmetrical with respect to all the straight lines which bisect the static pressure pad. With this static pressure pad, there is provided the double-disc grinding machine and a double-disc grinding method for the semiconductor wafer, which can minimize a “middle ring” of average components obtained by averaging a nanotopography of the wafers after the double-disc grinding.