Method for dechucking a workpiece from an electrostatic chuck
US5684669A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jun 7, 1995 |
| Grant date | Nov 4, 1997 |
| Priority date | — |
| Expiry date | Jun 7, 2015 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH02N13/00
- WIPO fieldSemiconductors
- WIPO sectorElectrical engineering
Abstract
A method of dechucking a workpiece from an electrostatic chuck. The method adaptively produces a dechucking voltage for canceling any unpredictable residual electrostatic fields between a workpiece and the electrostatic chuck. The method contains the steps of (a) applying a lifting force to the workpiece; (b) altering the chucking voltage; (c) measuring the lifting force; (d) comparing the measured lifting force to a threshold level; and, depending on the result of the comparison, either (e) maintaining the chucking voltage at its present level for a predefined period of time and physically dechucking the workpiece or (f) repeating steps (b), (c), (d) and (e).
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.