Method for protection of lithographic components from particle contamination
US6253464A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Aug 18, 2000 |
| Grant date | Jul 3, 2001 |
| Priority date | — |
| Expiry date | Aug 18, 2020 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG03F7/70983
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
A system that employs thermophoresis to protect lithographic surfaces from particle deposition and operates in an environment where the pressure is substantially constant and can be sub-atmospheric. The system (thermophoretic pellicle) comprises an enclosure that surrounds a lithographic component whose surface is being protected from particle deposition. The enclosure is provided with means for introducing a flow of gas into the chamber and at least one aperture that provides for access to the lithographic surface for the entry and exit of a beam of radiation, for example, and further controls gas flow into a surrounding low pressure environment such that a higher pressure is maintained within the enclosure and over the surface being protected. The lithographic component can be heated or, alternatively the walls of the enclosure can be cooled to establish a temperature gradient between the surface of the lithographic component and the walls of the enclosure, thereby enabling the thermophoretic force that resists particle deposition.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.