Polarization beam splitter for photolithography
US6680794B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Oct 4, 2002 |
| Grant date | Jan 20, 2004 |
| Priority date | — |
| Expiry date | Oct 4, 2022 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG02B27/283
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
The present invention provides a photolithography system having a catadioptric system with a polarizing beam splitter cube. The beam splitter cube transmits light at wavelengths equal to or less than 170 nm. The polarizing beam splitter cube can image at high quality light incident over a wide range of angles and including a numeric aperture greater than 0.6. In one embodiment, the polarizing beam splitter cube comprises a pair of prisms that are made of at least a fluoride material, such as calcium fluoride, and a coating interface having at least one layer of a thin film fluoride material. Layers in a multi-layer stack can also be graded across the hypotenuse face of a prism to adjust layer thicknesses at any point so as to compensate for changes in the incidence angle of the light. In one embodiment, the prisms and coating interface are joined by optical contact.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.