Optical technique for detecting buried defects in opaque films
US7027142B2 · kind B2 · utility
Assignee
Inventor
Key dates
| Filing date | Apr 25, 2003 |
| Grant date | Apr 11, 2006 |
| Priority date | — |
| Expiry date | Mar 11, 2024 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01N2201/104
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A local area of a sample is focally heated to produce a transient physical deformation. The surface of the structure is optically monitored while the heated area cools to a baseline temperature by illuminating the heated region with one or more probe beams from time to time and detecting returning light. In some embodiments heat dissipation within the structure is correlated with change in optical reflectivity over time. In other embodiments, surface deformation of the structure is correlated with changes in light scattering from the surface. Following application of a pump pulse and no more than 3 probe pulses, a time varying returning light signal is compared with a corresponding returning light signal from a reference. An anomaly in the sample is indicated by a deviation between the two signals. First-degree exponential decay curves may be constructed from the signals, and their decay constants compared.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.