Position detecting method and device therefor as well as aligning device
US5182610A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Apr 19, 1991 |
| Grant date | Jan 26, 1993 |
| Priority date | — |
| Expiry date | Apr 19, 2011 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG03F9/7049
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
The present invention relates to position detection, and aligning structure utilizing optical heterodyne method in semiconductor ultra fine processing or ultra accurate measuring. This is to provide a structure which contains pitches of not less than two kinds with respect to grating pitches of diffraction gratings which directly give influences to signal detecting range and detecting resolution, or which contains different values of not less than two kinds with respect to absolute values n of an order of .+-.n-th order injecting directions (or .+-.n-th order diffraction directions) to be determined by said grating pitches, so as to enable to enlarge a detecting range as maintaining a required detecting resolution (or a structure which can take out diffracted lights in different diffraction directions of not less than two).
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.