Chinese Optics Letters, Volume. 4, Issue 4, 04237(2006)
Analysis of illumination pupil filling ellipticity for critical dimensions control in photolithography
Shrinking of critical dimensions (CDs) in semiconductor circuits has been pushing optical lithography to print features smaller than the wavelength of light source. The demand for CD control is ever-increasing. In this paper, the study is conducted to reveal the impact of illumination pupil filling ellipticity on CD uniformity. As main parameters of CD uniformity, horizontal-vertical feature bias (H-V bias) and isolated-dense feature bias (I-D bias) caused by pupil filling ellipticity are calculated using the PROLITH software under four different illumination settings. Simulation shows that H-V bias and I-D bias are proportional to the pupil filling ellipticity. The slopes of the fitting lines of the H-V bias versus pupil filling ellipticity are calculated.
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Liping Guo, Xiangzhao Wang, Huijie Huang. Analysis of illumination pupil filling ellipticity for critical dimensions control in photolithography[J]. Chinese Optics Letters, 2006, 4(4): 04237