1 July 2005 Mask-induced polarization effects at high numerical aperture
Author Affiliations +
Abstract
Degradation in image contrast becomes a concern at higher numerical apertures (NAs) due to mask-induced polarization effects. We study how different photomask materials (binary and attenuated phase shift), feature sizes and shapes, pitch values, duty ratios (line to space), and wavelengths effect the polarization of transmitted radiation. Rigorous coupled-wave analysis (RCWA) is used to simulate the polarization of radiation by the photomask. The results show that higher NA leads to greater polarization effects in all cases. Off-axis illumination increases polarization in one of the first orders, decreasing it in the other. Nonvertical sidewall angles and rounded corners can also impact polarization, but the wavelength of incident radiation has no effect on polarization effects at the same NA values. In general, materials with higher refractive indices and lower extinction coefficients tend to pass more of the TM polarization state, whereas materials with lower refractive indices and a relatively wider range of extinction coefficients pass more TE polarized radiation. These properties can provide new design considerations for the development of next-generation masking materials.
©(2005) Society of Photo-Optical Instrumentation Engineers (SPIE)
Andrew Estroff, Yongfa Fan, Anatoly Bourov, and Bruce William Smith "Mask-induced polarization effects at high numerical aperture," Journal of Micro/Nanolithography, MEMS, and MOEMS 4(3), 031107 (1 July 2005). https://doi.org/10.1117/1.2037507
Published: 1 July 2005
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CITATIONS
Cited by 16 scholarly publications and 8 patents.
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KEYWORDS
Polarization

Polarizers

Refractive index

Binary data

Photomasks

Chromium

Metals

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