Simple electromechanical tilt and focus device
US4504144A · kind A · utility
60Cited by
7References
5Claims
0Family size
Assignee
Inventor
Key dates
| Filing date | Jul 6, 1982 |
| Grant date | Mar 12, 1985 |
| Priority date | — |
| Expiry date | Jul 6, 2002 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG03F9/70
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
An apparatus automatically for correcting tilt and focus errors of a wafer in a mask projection system for a plurality of subfields on the wafer which vary in position according to a known scheme. The tilt and focus of each subfield on the wafer is individually corrected by three axial actuators operating on the variable X and Y coordinates of the center of each subfield and its tilt and focus errors.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.