Method and apparatus for alignment
US4777641A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Oct 14, 1986 |
| Grant date | Oct 11, 1988 |
| Priority date | — |
| Expiry date | Oct 14, 2006 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG03F9/70
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
A method and apparatus for alignment for use in X-ray exposure or the like wherein a mask is provided having a formation of an alignment pattern made up of at least one linear segment formed in a peripheral section of the mask and a wafer is provided having a formation of an alignment pattern formed in a same direction as the alignment pattern of the mask and made up of linear segments. An illuminating arrangement illuminates a light to the mask alignment pattern along a direction inclined to the alignment direction and the mask alignment pattern and the wafer alignment pattern are imaged and transformed into a video signal. An A/D converts the video signal into a digital signal and stores the digital signal in a memory. The digital video signal is read out from the memory and averaged in a mask alignment pattern by removing a shadow portion caused by the mask alignment pattern and additionally averaged in a wafer alignment pattern area with an averaged wafer alignment pattern signal and an averaged wafer alignment pattern signal being provided. Relative displacement between the mask and the wafer is detected from the averaged mask alignment pattern signal and the averaged wafer al…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.