Optical metrology system for spectral imaging of a sample

Abstract

An optical metrology device is capable of detection of any combination of photoluminescence light, specular reflection of broadband light, and scattered light from a line across the width of a sample. The metrology device includes a first light source that produces a first illumination line on the sample. A scanning system may be used to scan an illumination spot across the sample to form the illumination line. A detector spectrally images the photoluminescence light emitted along the illumination line. Additionally, a broadband illumination source may be used to produce a second illumination line on the sample, where the detector spectrally images specular reflection of the broadband illumination along the second illumination line. The detector may also image scattered light from the first illumination line. The illumination lines may be scanned across the sample so that all positions on the sample may be measured.

What is claimed is: 
     
         1 . An apparatus comprising:
 a light source that produces an illumination beam;   a optical system that receives the illumination beam and produces an illumination spot on a surface of the sample;   a scanning system that scans the illumination spot to form an illumination line across the sample, wherein the scanning system scans the illumination beam in a plane that is at a non-normal angle of incidence on the sample, and wherein the sample emits photoluminescence light in response to excitation caused by the illumination spot along the illumination line;   a stage for providing relative movement between the illumination line and the sample;   a detector that receives the photoluminescence light emitted along the illumination line on an array that represents spectral information of the photoluminescence light, and wherein the detector produces a plurality of spectral information with respect to spatial position for the illumination line on the surface of the sample as the stage produces relative movement between the illumination line and the sample; and   a processor coupled to the detector to receive the plurality of spectral information with respect to spatial position and characterizes the sample based on the spectral information with respect to spatial position.