| 摘要 |
PROBLEM TO BE SOLVED: To improve the temperature uniformity of a work by making the distances between surfaces at the mounting surface sides of refrigerant path chambers and a mounting surface different, depending on the radius position, in a vacuum chuck for holding the work on the mounting surface. SOLUTION: In a vacuum chuck for mounting a wafer 5 as a work, tubular refrigerant path chambers 22 are approximately concentrically disposed. The distance between the top end of the outermost refrigerant path chambers 22 and a water 5 mounting surface is set to be less than the distance between the top end of the inner refrigerant path chambers 22 and the wafer 5 mounting surface. The radial width of a section of the outermost refrigerant pass chambers 22 is set to be less than the sectional area of other each inner chamber 22. This increases the sectional area of the refrigerant path chambers 22 to decrease the flow velocity of a refrigerant, thereby avoiding reducing the heat transfer from the chamber 22 surface to the refrigerant. Thus the temperature rise is reduced at the peripheral part of the wafer 5 to uniformize the temperature distribution over the wafer 5. |
