Ellipsometer and method of controlling coating thickness therewith
US5438415A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Sep 22, 1992 |
| Grant date | Aug 1, 1995 |
| Priority date | — |
| Expiry date | Sep 22, 2012 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01B11/065
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
An ellipsometer has a nonpolarization beam splitter (18) for dividing reflected light (17) from an object to be measured (16) into portions traveling along first and second optical paths (18a, 18b), an analyzer (19) for passing the polarized light component in a reference direction of the reflected light portion traveling along the first optical path, and a polarization beam splitter (20) for dividing the reflected light portion traveling along the second optical path into two polarized light components in different directions with respect to the reference direction. The light beams passing through the analyzer (19) and polarization beam splitter (20) are sensed by first, second and third photodetectors (21a, 21b, 21c), respectively. In a coating thickness control method, first and second ellipsometers (35a, 35b) are placed before and after a coating apparatus (36) provided along the transport path of a belt-like plate to be coated (31). A first ellipsoparameter (.DELTA.1,.psi.1) for the surface of the plate before coating is obtained with the first ellipsometer (35a). A second ellipsoparameter (.DELTA.2,.psi.2) for the surface of the plate after coating is obtained with the second…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.