| 摘要 |
A workpiece support assembly in a processing chamber, the assembly including a support member having an upper surface to be contacted by a workpiece and a lower surface located opposite the upper surface; and a workpiece position monitoring system mounted on the lower surface and isolated from the interior of the chamber for detecting contact between the upper surface and a workpiece at each of a plurality of individual locations on the upper surface. The workpiece position monitoring system consists of a plurality of electroacoustic signal transducers mounted on the lower surface of the support member for generating acoustic waves in the support member and receiving reflected acoustic waves. The intensity of acoustic waves reflected from the upper surface is monitored to determine the position of a workpiece, such as a semiconductor wafer, on the support member.
|
