SBIR Phase I: Vacuum UV Spectroscopic ellipsometer for semiconductor lithography

This Small Business Innovation Research (SBIR) Phase I project will test a novel method for Vacuum Ultraviolet (VUV) spectroscopic ellipsometry (SE) measurements for process control and monitoring in semiconductor lithography applications. It builds on the demonstrated success of employing planar grating diffraction to achieve SE measurements in the visible wavelengths. For SE measurements in the VUV, it is necessary to employ conical diffraction geometries which do not require sheet-type polarizing elements in the detection system. This permits the construction of a Conical Diffraction- Grating Division of Amplitude Photopolarimeter (CD-GDOAP) that is the analyzer/detection system in the VUV-SE. By intercepting four or more dispersed orders of the cone of diffraction, a CD-GDOAP can measure the polarization state of light over the full spectrum in the VUV with no moving parts. The VUV-SE will: (i) operate in the 140-280 nm spectral range, (ii) have no moving parts, and (iii) provide high temporal resolution. In Phase I, we propose to characterize the performance of a laboratory breadboard CD-GDOAP by investigating (i) conical diffraction geometries, (ii) robustness of polarization detection, and (iii) performance of optical components in the VUV. If successful, it will lead to a compact, high-speed VUV-SE for use in semiconductor processing. Potential Commercial Applications of the Research The proposed SE based on CD-GDOAP will permit real-time measurements for VUV lithography applications at 157, 193, and 248 nm in a single instrument. Presently there are no commercially available instruments (used in production facilities) that can access all of these wavelengths. Successful completion of this project will ensure rapid entry into the marketplace, through the business relationship that CRI is developing with major semiconductor metrology equipment companies