| 摘要 |
Disclosed is a wafer chuck, which has protrusions for supporting a substrate, for attracting and holding the substrate by negative pressure while the substrate is being supported by the protrusions. The wafer chuck includes pin-shaped protrusions dispersed on a suction side of the chuck, and circular peripheral wall portions disposed in the vicinity of the rim of the supported substrate and in the vicinity of the outer peripheral portion of a lifting hole, respectively. The suction side of the wafer chuck is provided with a first area in which the pin-shaped protrusions are arrayed in a grid-line manner, and a second area in which the pin-shaped protrusions are arrayed in circumferential form. The second area is provided in the vicinity of the peripheral wall portion and peripheral wall portion, and the first area is provided elsewhere.
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