| 摘要 |
PROBLEM TO BE SOLVED: To provide a substrate excellent in surface flatness by mounting a truncated conical flexible film hollowed in the center on the circumference of a truncated conical washer so as to form a highly airtight space by the washer and the flexible film, and connecting an air feed pipe and an air pressure reducing pipe to an air passage provided on the washer. SOLUTION: A washer 6 has a small screw bore on the circumferential upper edge, and it is opened in the upper end. A flexible film 5 having a truncated conical circumference and hollowed in the center is mounted thereon to form a chamber by the bottom of the flexible film 5 and a washer bottom 6c. A flexible pipe 8 which forms an air passage usable by one as both a pipe for feeding pressure air and a pipe for reducing the pipe internal pressure is connected to an air passage 6d extending from the head of the washer 6 to the bottom 6a thereof. According to this structure, the pressure air is supplied to the chamber formed by the washer bottom 6c and the flexible film 5, whereby the flexible film 5 is expanded to form a pressurization chamber. Therefore, a uniform pressure according to the surface state of the abrasive cloth of a platen can be transmitted to a substrate to enhance the surface smoothness of the substrate. |
