| 摘要 |
PURPOSE:To hold substrates always with a certain adsorbing force by forming a variable volume chamber in an adsorbing chuck and applying an action of a weight on the bottom wall of the variable volume chamber. CONSTITUTION:An adsorbing chuck 1 comprises an adsorbing head 16 formed on the upper surface with a substrate holding surface 15, a housing section 17, a rod 18 and a weight 19. In the housing section 17 is received a bellows 20 fixed to the lower surface of the adsorbing head 16 on the upper end. The rod 18 fitted in the weight 19 is fixed to the bottom wall of bellows 20. In this constitution, when a substrate W is mounted on the adsorbing head 16 and a lifter is lowered, the weight of weight 19 acts on the bottom wall of bellows 20 through the rod 18, so that the bellows 20 is expanded to reduce the internal pressure in a variable volume chamber 21 and adsorb the substrate W through a communicating path 22.
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