| 摘要 |
The present invention relates in particular to electrostatic holding devices for holding semiconductor wafers and other materials during processing operations, such as vacuum sputtering, for example. One problem with such holding devices is that a residual electrostatic charge tends to build up on the surface of the device. This can lead to problems in the release of the wafer when processing is completed, as this electrostatic charge will tend to grip the wafer. The present invention overcomes this problem by determining a value of drive voltage to be applied to the electrostatic chuck to cancel out the holding effects of at least most of the residual electrostatic charge and thus enable release of the wafer. The value of drive voltage to be applied to allow release is determined by monitoring motion of the wafer as the drive voltage is varied, the motion of the wafer being indicative of whether it is being gripped by the body or not.
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