22 March 2008 Assessing scatterometry for measuring advanced spacer structures with embedded SiGe
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This paper discusses the scatterometry-based measurement of a complex thin-spacer PFET structure containing an embedded SiGe (eSiGe) trench. The thickness of the spacer and the overfill of the eSiGe trench are critical measurement parameters for such a structure. Although the corresponding NFET structure does not contain the eSiGe-filled trench, it is also found to be a good barometer of thin-spacer measurement capability and so is also used in the study. First, the paper discusses the dispersion analysis challenges and approaches for these 45 nm node structures. Next, two sets of scatterometry hardware, one in production and one under development, are used to measure the critical parameters in order to understand the differences in measurement performance between the systems. Transmission Electron Microscopy (TEM) analysis is used as a reference metrology to assess the accuracy performance of the hardware. Results show that the advanced optics of the newer system significantly improves the dynamic repeatability of the parameters compared to the older system, while the newer system's extended wavelength range down into the deep UV (DUV) can provide a noticeable improvement in measurement accuracy due to the significantly greater parameter sensitivity in this wavelength range.
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Matthew Sendelbach, Matthew Sendelbach, Shahin Zangooie, Shahin Zangooie, Alok Vaid, Alok Vaid, Pedro Herrera, Pedro Herrera, Jingmin Leng, Jingmin Leng, InKyo Kim, InKyo Kim, } "Assessing scatterometry for measuring advanced spacer structures with embedded SiGe", Proc. SPIE 6922, Metrology, Inspection, and Process Control for Microlithography XXII, 69220R (22 March 2008); doi: 10.1117/12.774823; https://doi.org/10.1117/12.774823

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