Wafer holding device and wafer chucking and dechucking method

A wafer holding device, comprising:

• a wafer chuck that includes a wafer holding surface coming into contact with a wafer to be held and a plurality of attraction regions provided on the wafer holding surface;
• and
• a controller configured to independently control an attraction force of an at least one of the plurality of attraction regions,
• wherein in a case where fixing of the wafer is released, the controller establishes a temporarily fixing state in which the attraction force of the at least one of the plurality of attraction regions is smaller than an attraction force in fixing the wafer, and thereafter, the controller sets attraction forces of all of the plurality of attraction regions to be smaller than the attraction force in fixing the wafer,
• wherein the plurality of attraction regions include a first attraction region and a second attraction region, and
• wherein in the case where the fixing of the wafer is released, the controller establishes a first temporarily fixing state in which an attraction force of the second attraction region is smaller than the attraction force in fixing the wafer while maintaining an attraction force of the first attraction region to be the attraction force in fixing the wafer, and thereafter, the controller establishes a second temporarily fixing state in which the attraction force of the first attraction region is smaller than the attraction force in fixing the wafer while maintaining the attraction force of the second attraction region to be the attraction force in fixing the wafer.

A wafer chucking and dechucking method using a wafer chuck, in which the wafer chuck includes a wafer holding surface coming into contact with a wafer to be held and a plurality of attraction regions provided on the wafer holding surface, the method comprising:

• in a case where fixing of the wafer is released, establishing a temporarily fixing state in which an attraction force of an at least one of the plurality of attraction regions is smaller than an attraction force in fixing the wafer;
• and
• thereafter, setting attraction forces of all of the plurality of attraction regions to be smaller than the attraction force in fixing the wafer,
• wherein establishing the temporarily fixing state includes sequentially switching the at least one of the plurality of attraction regions having the attraction forces smaller than the attraction force in fixing the wafer while preventing all of the plurality of attraction regions from simultaneously having the attraction forces smaller than the attraction force in fixing the wafer.