16 June 2003 Lithographic characterization of improved projection optics in the EUVL engineering test stand
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Abstract
Static and scanned images of 100nm dense features for a developmental set of l/14 optics (projection optics box # 1, POB 1) in the Engineering Test Stand (ETS) were successfully obtained with various LPP source powers last year. The ETS with POB1 has been used to understand initial system performance and lithographic learning. Since then, numerous system upgrades have been made to improve ETS lithographic performance to meet or exceed the original design objectives. The most important upgrade is the replacement of POB 1 with an improved projection optics system, POB2, having lower figure error (l/20 rms wavefront error) and lower flare. Both projection optics boxes are a four-mirror design with a 0.1 numerical aperture. Scanned 70-nm dense features have been successfully printed using POB2. Aerial image contrast measurements have been made using the resist clearing method. The results are in good agreement to previous POB2 aerial image contrast measurements at the subfield exposure station (SES) at Lawrence Berkeley National Laboratory. For small features the results deviate from the modeling predictions due to the inherent resolution limit of the resist. The intrinsic flare of POB2 was also characterized. The experimental results were in excellent agreement with modeling predictions. As predicted, the flare in POB2 is less than 20% for 2μm features, which is two times lower than the flare in POB1. EUV flare is much easier to compensate for than its DUV counterpart due to its greater degree of uniformity and predictability. The lithographic learning obtained from the ETS will be used in the development of EUV High Volume Manufacturing tools. This paper describes the ETS tool ETS tool setup, both static and scanned, that was required after the installation of POB2. The paper will also describe the lithographic characterization of POB2 in the ETS and cmpare those results to the lithographic results obtained last year with POB1.
© (2003) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Donna J. O'Connell, Sang Hun Lee, William P. Ballard, Daniel A. Tichenor, Louis J. Bernardez, Steven J. Haney, Terry A. Johnson, Pamela K. Barr, Alvin H. Leung, Karen L. Jefferson, William C. Replogle, John E. M. Goldsmith, Henry N. Chapman, Patrick P. Naulleau, Stefan Wurm, Eric M. Panning, "Lithographic characterization of improved projection optics in the EUVL engineering test stand", Proc. SPIE 5037, Emerging Lithographic Technologies VII, (16 June 2003); doi: 10.1117/12.484967; https://doi.org/10.1117/12.484967
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