Apparatus for evaluating metalized layers on semiconductors
US5978074A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jul 3, 1997 |
| Grant date | Nov 2, 1999 |
| Priority date | — |
| Expiry date | Jul 3, 2017 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01N21/1717
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
An apparatus for characterizing multilayer samples is disclosed. An intensity modulated pump beam is focused onto the sample surface to periodically excite the sample. A probe beam is focused onto the sample surface within the periodically excited area. The power of the reflected probe beam is measured by a photodetector. The output of the photodetector is filtered and processed to derive the modulated optical reflectivity of the sample. Measurements are taken at a plurality of pump beam modulation frequencies. In addition, measurements are taken as the lateral separation between the pump and probe beam spots on the sample surface is varied. The measurements at multiple modulation frequencies and at different lateral beam spot spacings are used to help characterize complex multilayer samples. In the preferred embodiment, a spectrometer is also included to provide additional data for characterizing the sample.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.