Method and apparatus for measuring lateral variations in thickness or refractive index of a transparent film on a substrate
US6801321B1 · kind B1 · utility
Assignee
Inventor
Key dates
| Filing date | Feb 7, 2001 |
| Grant date | Oct 5, 2004 |
| Priority date | — |
| Expiry date | Feb 7, 2021 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG03F7/70608
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
A method or apparatus for measuring lateral variations of a property such as thickness or refractive index of a transparent film on a semiconductor, in a region of repeated patterning comprises: illuminating over the patterned area with a beam of light of multiple wavelengths, the beam having dimensions to include repeated patterning; detecting the intensity of light reflected over the patterned area for each wavelength; producing a signal defining the variation of the intensity of the detected light as a function of the wavelength of the detected light; decomposing the signal into principal frequencies thereof, determining from the principal frequencies, values of the thickness etc. of the transparent film; and applying the values to repetitions within the repeated patterning.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.