Differential wavelength photoluminescence for non-contact measuring of contaminants and defects located below the surface of a wafer or other workpiece
US7446321B2 · kind B2 · utility
Assignee
Inventors
Key dates
| Filing date | Jun 28, 2006 |
| Grant date | Nov 4, 2008 |
| Priority date | — |
| Expiry date | Jun 28, 2026 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01N2021/8867
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A method for using photoluminescence to identify defects in a sub-surface region of a sample includes performing a first probe of the sample. A first data set, based on the first probe, is produced indicating defects located primarily in a surface layer of the sample. A second data set, based on a second probe, is produced indicating defects located in both the surface layer and a sub-surface region of the sample. The first data set is subtracted from the second data set to produce a third data set indicating defects located primarily in the sub-surface region of the sample. The first data set may optionally be normalized relative to the second data set before performing the subtraction. The first and second probes may advantageously be performed using a first laser and a second laser, respectively, having different wavelengths from each other.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.