| 摘要 |
A rubber sheet (30) is arranged between a head body (22) and a retainer ring (28) of a wafer holding head (14). Two O-rings (46, 56) air-tightly close a space between the periphery of the rubber sheet (30), which is located above the retainer ring (28), and the head body (22). When a pump (44) supplies the compressed air to the space, the periphery of the rubber sheet (30) is elastically deformed to press the retainer ring (28) under uniform pressure. <IMAGE> |
