Alignment method, projection exposure method, and projection exposure apparatus
US5850279A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Mar 20, 1996 |
| Grant date | Dec 15, 1998 |
| Priority date | — |
| Expiry date | Mar 20, 2016 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG03F9/70
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
Disclosed is a projection exposure method for transferring a pattern formed on a mask onto a photosensitive substrate through a projection optical system. A light beam having a first wavelength for exposure is radiated through the projection optical system onto a first mark area including a fiducial mark on a fiducial plate installed on a substrate stage, reflected light from the first mark area is detected to obtain a position of the fiducial mark. A light beam having a second wavelength to which the photosensitive substrate is not photosensitive is radiated through the projection optical system onto the first mark area, reflected light from the first mark area is detected to obtain a position of the fiducial mark. A positional discrepancy of the fiducial mark caused by the difference in wavelength between the first and second wavelengths is previously calculated on the basis of results of the detection. The light beam having the second wavelength is radiated through the projection optical system onto an alignment mark on the photosensitive substrate, reflected light therefrom is detected to obtain a position of the photosensitive substrate under the light beam having the second w…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.