This program aims to develop standards, methods, and modeling for assessing the periodic structures using optical reflectance and transmittance measurements.
In the past few years, scatterometry has emerged as a method for performing linewidth and line profile metrology, especially by the semiconductor industry. The method uses a periodic target containing repetitive lines whose profile, i.e., its width, height, and shape, is to be determined. The technique relies on the complicated behavior that the grating structure has on the diffracted light as a function of incident angle and wavelength, and the sensitivity to small changes in the grating profile. By comparing measurements with a library of calculated model results, the profile can be inferred. While the method claims extreme sub-nanometer-level sensitivity to the line profile, there are a number of outstanding issues that the user community has regarding the technique's absolute accuracy. Some of these issues are outlined below:
This program aims to address these and other issues both theoretically and experimentally.
Lead Organizational Unit:pml
Related Programs and Projects:
Optical grating scatterometry:
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