Wavelet analysis for laser ultrasonic measurement of material properties
US5724138A · kind A · utility
25Cited by
18References
12Claims
0Family size
Assignee
Inventors
Key dates
| Filing date | Apr 18, 1996 |
| Grant date | Mar 3, 1998 |
| Priority date | — |
| Expiry date | Apr 18, 2016 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01N2291/2634
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A laser ultrasonics technique is used to characterize a composite dispersive response signal from a sample under analysis, such as a semiconductor wafer. Rather than measuring individual acoustic wave velocities at specific frequencies, an entire dispersive response signal is analyzed. In a presently preferred embodiment of this invention the entire dispersive response signal is analyzed using a wavelet-based technique, such as a discrete wavelet transform analysis technique. The discrete wavelet transform analysis technique is shown to provide an accurate, non-contact measurement of the temperature of the wafer.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.