Apparatus and method for fine alignment of a photomask to a semiconductor wafer
US4265542A · kind A · utility
14Cited by
4References
10Claims
0Family size
Assignee
Inventor
Key dates
| Filing date | Mar 14, 1979 |
| Grant date | May 5, 1981 |
| Priority date | — |
| Expiry date | Mar 14, 1999 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG02B27/4255
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
A method and apparatus are disclosed for fine aligning a photomask to a semiconductor using the interference and diffraction effects produced by coherent light impinging upon or passing through repetitive patterns on a photomask and a semiconductor. A plurality of photodetectors are employed to convert the interference information into phase dependent electrical signals that are used to control conventional X, Y and .theta. workpiece positioning mechanisms.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.