Patent ID: 7988216

Claim:
A holding apparatus for holding a semiconductor wafer, wherein the semiconductor wafer has a notch, the holding apparatus comprising: a pneumatic cylinder; a plunger, movably disposed at a central position of the pneumatic cylinder, comprising a curved surface; an inlet pipe, connected to the pneumatic cylinder, the pneumatic cylinder and plunger arranged such that air pumped into the pneumatic cylinder through the inlet pipe impels the plunger in a first direction to contact the wafer and bring the curved surface into abutment with opposite sides of the notch, thereby distributing an impact force of the plunger along two different directions, wherein the first direction and the curved surface are in line with a radius of the wafer; and a relief valve, connected to the inlet pipe, wherein a portion of the air in the inlet pipe is discharged through the relief valve to regulate air pressure to the pneumatic cylinder.