System and method for optimizing the electrostatic removal of a workpiece from a chuck
US6898064B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Aug 29, 2001 |
| Grant date | May 24, 2005 |
| Priority date | — |
| Expiry date | Apr 9, 2022 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01L21/6831
- WIPO fieldSemiconductors
- WIPO sectorElectrical engineering
Abstract
A system and method are presented for neutralizing the electric charge binding a semiconductor wafer to an electrostatic chuck. When processing of a semiconductor wafer has been completed, lifter pins, driven by solenoids or pistons, are provided within the chuck to remove the wafer. However, if the electrostatic force has not been completely dissipated, the pins may have to push very hard against the wafer to dislodge it. When this occurs, the wafer may be violently displaced from the chuck, resulting in misplacement of the wafer, or even damage. A system and method are disclosed herein for completely neutralizing the electrostatic charge before removal of the wafer is attempted. Neutralization is detected as the point at which the electrostatic force opposing the lifting mechanism reaches a minimum.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.