Nanometrics Inc.

Tom Walker

Steven G Hummel

Amit Shachaf

Andrzej Buczkowski

Nicolas Laurent

A method and apparatus uses photoluminescence to identify defects in one or more specified material layers of a sample. One or more filtering elements are used to filter out predetermined wavelengths of return light emitted from a sample. The predetermined wavelengths are selected such that only return light emitted from one or more specified material layers of the sample is detected. Additionally or alternatively, the wavelength of incident light directed into the sample may be selected to penetrate the sample to a given depth, or to excite only one or more selected material layers in the sample. Accordingly, defect data characteristic of primarily only the one or more specified material layers is generated.

Photoluminescence imaging with preferential detection of photoluminescence signals emitted from a specified material layer of a wafer or other workpiece

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.

Differential wavelength photoluminescence for non-contact measuring of contaminants and defects located below the surface of a wafer or other workpiece

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Portland, OR, United States of America

Tom Walker