Method of determining a dechucking voltage which nullifies a residual electrostatic force between an electrostatic chuck and a wafer
US5491603A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Apr 28, 1994 |
| Grant date | Feb 13, 1996 |
| Priority date | — |
| Expiry date | Apr 28, 2014 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01L21/6833
- WIPO fieldSemiconductors
- WIPO sectorElectrical engineering
Abstract
The invention is embodied in a method of determining an optimum de-chucking voltage for nullifying residual electrostatic forces on a wafer in an electrostatic chuck for removal of the wafer from the chuck, including holding the wafer on the electrostatic chuck by applying an electrostatic potential to the chuck, introducing a gas between the wafer and the chuck, reducing the electrostatic potential of the chuck while observing a rate of leakage of the gas from between the wafer and the chuck, and recording as the optimum dechucking voltage the value of the electrostatic potential obtaining when the rate of leakage exceeds a predetermined threshold.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.