Polariscope stress measurement tool and method of use
US8264675B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Sep 15, 2011 |
| Grant date | Sep 11, 2012 |
| Priority date | — |
| Expiry date | Sep 15, 2031 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01L5/0047
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
The present invention provides a tool for and method of using an infrared transmission technique to extract the full stress components of the in-plane residual stresses in thin, multi crystalline silicon wafers including in situ measurement of residual stress for large cast wafers. The shear difference method is used to obtain full stress components by integrating the shear stress map from the boundaries. System ambiguity at the boundaries is resolved completely by introducing a new analytical function. A new anisotropic stress optic law is provided, and stress optic coefficients are calibrated for different crystal grain orientations and stress orientations.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.