| 摘要 |
PURPOSE:To remarkably reduce deformation of a plate so as to enhance the flatness of a wafer by placing, in a state of fitting, a pressing ring having a space for water supply inside a top ring which presses a plate having wafers stuck thereon, onto a rotary surface plate. CONSTITUTION:A pressing ring 10 is placed, in a state of fitting, inside a top ring 3 which pressed a glass plate 2, on which a plurality of wafer 'a' are stuck, onto a surface plate 1, a recess 13 serving as a water supply is formed between the inner ring 14 and the outer ring 15 of the pressing ring 10, O rings 18, 19 and 4 are set on the bottom surfaces 14a and 15a of both rings and the bottom surface 3a of the top ring 3 respectively, and a load is applied on the plate 2 via those rings serving as loading points. Further, cooling water flows into the recess 13 from a recess chamber 11 through communication holes 16 and is discharged from a discharge pipe 21 through communication holes 17 and a central hole 12 after cooling the plate 2. Thus, the positional intervals of loading points can be shortened and the temperature distribution on the upper face of the plate is uniformalized. Accordingly deformation of the plate is small and the polishing accuracy (flatness) of wafers can be enhance. |
