Methods for nondestructive measurements of thickness of underlying layers
US10989520B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Dec 16, 2019 |
| Grant date | Apr 27, 2021 |
| Priority date | — |
| Expiry date | Dec 16, 2039 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01B11/0625
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A method for nondestructive measurement of an underlying layer thickness includes irradiating, with a pump laser pulse, a sample to induce generation of an acoustic wave in the sample such that the acoustic wave propagates through the sample over time, where the sample includes a substrate, an underlying layer on the substrate, and an overlying layer on the underlying layer and the underlying layer is isolated from an exterior of the sample by at least the overlying layer, irradiating the sample with a probe laser pulse after irradiating the sample with the pump laser pulse, determining a reflectance variation of the sample over time, based on monitoring a variation of a reflection of the probe laser pulse from the sample over time, to generate a first graph showing a variation of reflectance of the sample over time, and determining a thickness of the underlying layer based on the first graph.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.