Devices and methods for thermophoretic and electrophoretic reduction of particulate contamination of lithographic reticles and other objects
US7875864B2 · kind B2 · utility
Assignee
Inventor
Key dates
| Filing date | Apr 1, 2008 |
| Grant date | Jan 25, 2011 |
| Priority date | — |
| Expiry date | Jul 21, 2029 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG03F1/82
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
Apparatus and methods are disclosed for reducing particle contamination of a surface of an object such as a reticle used in an EUV lithography system. An exemplary apparatus includes a thermophoresis device and an electrophoresis device. The thermophoresis device is situated relative to and spaced from the surface, and is configured to produce a thermophoretic force, in a gas flowing past and contacting the surface, sufficient to inhibit particles in the gas from contacting the surface. The electrophoresis device is situated relative to a region of the surface contacted by the gas and is configured to deflect particles, having an electrostatic charge, in the gas away from the region as the gas flows past the region. In an example, the thermophoresis device produces the thermophoretic force by establishing a temperature gradient in the gas relative to the surface, and the electrophoresis device includes an electrode situated and configured to produce a voltage gradient relative to the region of the surface sufficient to attract charged particles away from the region of the surface.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.