Method and apparatus for optical alignment of semiconductor by using a hologram
US4862008A · kind A · utility
15Cited by
4References
40Claims
0Family size
Assignee
Inventors
Key dates
| Filing date | Jun 29, 1988 |
| Grant date | Aug 29, 1989 |
| Priority date | — |
| Expiry date | Jun 29, 2008 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG03F9/70
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
A wafer is aligned by using an alignment light having a longer wavelength than an exposure light. Exposure and alignment are effected through a common reduction lens. A wavefront aberration caused by the use of the long wavelength alignment light is compensated by a hologram. Thus, an alignment precision is improved without exposing a resist layer to a light.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.