Apparatus for detecting position of reference pattern
US4860374A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jul 6, 1988 |
| Grant date | Aug 22, 1989 |
| Priority date | — |
| Expiry date | Jul 6, 2008 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG06V10/443
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
An apparatus for detecting a position of a reference pattern or mark formed in a substrate to be aligned with a photomask pattern performs the following functions: scanning a reference pattern having at least two edges and generating a time-serial pattern signal corresponding to the scanned pattern; extracting all scanning positions at which a waveform of the pattern signal has a shape corresponding to an edge of the pattern within a predetermined scanning range including the pattern; selecting one pair from all possible pairs of a plurality of extracted scanning positions in accordance with a degree to which a pattern signal between the two scanning positions defined by each pair satisfies predetermined waveform conditions; and determining as a pattern position a predetermined position at which the interval between the two scanning positions of the selected pair is divided into two intervals by a predetermined ratio.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.