| 摘要 |
PROBLEM TO BE SOLVED: To unify the distribution of a film thickness on the whole face of a board by independently and concentrically controlling the working pressure, to automatically equalize the inclination of a board holding face to a grinding face of a grinding tool, and the camber, the waviness or the like of the board itself, to flatten the board with high accuracy, and to easily mount and demount the board. SOLUTION: This board holding device C1 comprises plural fluid chambers 2a, 2b, etc., concentrically defined in a frame body 1 opened at its board holding face side, plural concentric annular pistons 3a, 3b, etc., respectively vertically movable mounted on each of plural fluid chambers 2a, 2b, etc., and a pressurization and decompression controlling means 8 for independently increasing or decreasing the internal pressure in the plural fluid chambers 2a, 2b, etc., for independently moving the annular pistons 3a, 3b, etc., the board W is fitted to an inner peripheral side face 1i of the frame body 1, and held on surfaces of the independently positioned plural annular pistons 3a, 3b, etc., through a backing material 11. |
