Scanning laser lithography system alignment apparatus
US5327338A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Nov 9, 1992 |
| Grant date | Jul 5, 1994 |
| Priority date | — |
| Expiry date | Nov 9, 2012 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG03F7/704
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
A direct-write lithography tool having improved alignment characteristics. The present invention discloses use of an optical alignment apparatus in a multi-beam lithography system. The optical alignment apparatus provides for alignment through a reduction lens utilized by the multi-beam lithography system for writing to semiconductor wafers and the like through use of optics for correction of distortion and curvature caused by viewing with a radiant energy beam of a different wavelength than the beams used for writing. Further, the alignment optics provide for multiple paths in a single optics system through use of liquid crystal retarders and beam splitters to direct the radiant energy beam through a selected optical path. In the present invention, a first optical path may provide for high magnification and a second for low magnification. Further, other optical paths may provide for bright or dark field illumination and viewing.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.