Optically monitoring the thickness of a depositing layer
US4141780A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Dec 19, 1977 |
| Grant date | Feb 27, 1979 |
| Priority date | — |
| Expiry date | Dec 19, 1997 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01B11/0675
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A method of optically monitoring the thickness of a layer of material being deposited on a substrate within a reaction chamber comprises forming on a body a diffraction grating profile, exposing the grating profile to a beam of light while depositing the material on both the substrate and the grating profile, whereby the grating profile functions as a relief pattern diffracting the light beam into diffracted beams of various orders, measuring the intensity of the first order (I.sub.1) and second order (I.sub.2) beams to obtain a ratio signal (I.sub.2 /I.sub.1), and then transmitting the ratio signal to processing means for determining the aspect groove width of the relief pattern, whereby the thickness of the depositing layer is determined from a pre-established relationship dependent upon the aspect groove width.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.