Precision automatic mask-wafer alignment system
US4728193A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Dec 11, 1986 |
| Grant date | Mar 1, 1988 |
| Priority date | — |
| Expiry date | Dec 11, 2006 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG03F9/7049
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
An interferometric alignment and position detector system for determining relative location of an object is provided. A composite diffraction grating is provided with the object. A laser can provide a collimated coherent light beam directed so as to impinge on the composite diffraction grating. A beam splitter can collect at least two pairs of diffracted light beams from the composite diffraction grating and can combine the pairs of diffracted light beams to provide interference fringe patterns. Apparatus is provided for detecting the interference fringe patterns to provide a measurement of the intensity distribution from which the relative location can be established.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.