Integrated spectroscopic ellipsometer
US5596411A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Mar 18, 1996 |
| Grant date | Jan 21, 1997 |
| Priority date | — |
| Expiry date | Mar 18, 2016 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01N21/211
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
An optical inspection apparatus is disclosed for generating an ellipsometric output signal at a plurality of wavelengths, each signal being representative of an integration of measurements at a plurality of angles of incidence. A polarized, broad band light beam is focused through a lens onto a sample in a manner to create a spread of angles of incidence. The reflected beam is passed through a quarter-wave plate and a polarizer which creates interference effects between the two polarizations states in the beam. The beam is then passed through a filter which transmits two opposed radial quadrants of the beam and blocks light striking the remaining two quadrants. The beam is then focused and angularly dispersed as function of wavelength. Each element of a one dimensional photodetector array generates an output signal associated with a specific wavelength and represents an integration of the phase-sensitive ellipsometric parameter (.delta.) at a plurality of angles of incidence. A second, independent measurement is taken in order to isolate the signal of interest. In one embodiment, the azimuthal angle of the filter is rotated by ninety degrees. The output signals from the second meas…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.