Alignment method and apparatus for reduction projection type aligner
US4725737A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Nov 12, 1985 |
| Grant date | Feb 16, 1988 |
| Priority date | — |
| Expiry date | Nov 12, 2005 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG03F9/7076
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
An alignment method and apparatus for reduction projection type aligner in which the rough detection of reticle position in the reticle alignment process at the time of mounting a reticle and the fine detection of reticle position in the wafer alignment for the alignment between a wafer and the reticle are performed automatically by the same reticle alignment pattern and the same optical alignment detection system. A plurality of one- or two-dimensional Fresnel zone plates having different shapes of diffraction patterns formed outside of a reticle circuit pattern and arranged at a position outward of the entrance pupil of the reduction projection lens are used as a reticle alignment pattern to detect the absolute position of the reticle. The detection field of view of the optical alignment detection system is thus effectively widened to make pattern detection possible with high magnification for an improved detection accuracy. The same reticle alignment pattern and the same optical alignment detection system are used for rough detection of reticle position in reticle alignment and fine detection of reticle position in wafer alignment. In the optical alignment detection system, on t…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.