| 摘要 |
<p>PURPOSE:To provide a retaining equipment having excellent dust-proof effect in addition to characteristics of high rigidity, light weight and high dimensional stability. CONSTITUTION:On the wafer sucking surface of a wafer holder WH, ring type protruding parts (wafer W retaining parts) 1 of a concentric circle type (or a spiral type), and ring type recessed parts (vacuum suction grooves) 2 are formed at constant pitches. Suction holes 3 for vacuum suction are arranged and formed in the radial direction in the ring type recessed parts 2. Each of the suction holes 3 is linked with a sleeve type hole 4 stretching in the radial direction in the wafer holder WH. When pressure is decreased by connecting a vacuum source with the hole 4, a wafer is conformed to the upper surface of the ring type protruding parts 1, and corrected to be flat. At least the wafer contact part of the wafer holder WH (desirably, the whole part of the holder) is constituted of TiC-contained Al2O3 sintered body, which has conductivity and few voids particular to a sintered body.</p> |
