Method of and apparatus for applying voltage to electrostatic chuck
US5117121A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Apr 24, 1990 |
| Grant date | May 26, 1992 |
| Priority date | — |
| Expiry date | Apr 24, 2010 |
Classification
- Technology area (CPC B)Performing Operations; Transporting
- CPC primaryB23Q3/15
- WIPO fieldMachine tools
- WIPO sectorMechanical engineering
Abstract
A first voltage is first applied to the electrode or electrodes of an electrostatic chuck for electrostatically attracting a workpiece such as a silicon wafer. Then, before the workpiece is removed from the electrostatic chuck, a second voltage which is of opposite polarity to the first voltage is applied to the electrostatic chuck for eliminating a residual attractive force from the electrostatic chuck. The second voltage has a voltage value which is 1.5 to 2 times higher than the voltage value of the first voltage. The second voltage is continuously applied for a period of time which is in inverse proportion to the voltage value of the second voltage.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.