Browsing by Author "Yeh, KT"

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Modified reflectance-transmittance method for the metrology of thin film optical properties
(2006-03-01)
Yeh, KT
;
Lin, CH
;
Hu, JR
;
Loong, WA
;
應用化學系
Because the surface roughness of a thin film will cause light scattering, the reflectance (R) and transmittance (T) measured using a UV/visible (vis) spectrometer become lower than the actual values. The deviation becomes larger with increasing roughness and decreasing wavelength of incident light. Hence, it is necessary to correct measured R and T using roughness as a modification factor. The refraction (n) and extinction coefficient (k) obtained by the modified R-T method are closer to those results obtained using a variable angle spectroscopic ellipsometer (VASE), which provides more precise results than a n and k analyzer.
Simulations of mask error enhancement factor in 193nm immersion lithography
(2006-04-01)
Yeh, KT
;
Loong, WA
;
應用化學系
;
Department of Applied Chemistry
In general, better resolution and lower mask error enhancement factor (MEEF) are obtained when a higher numerical aperture (NA) is used. However, simulations in this study show that, if Y-polarized light and off-axis illuminations were used, higher NA leads to higher MEEF for smaller and dense feature line sizes in 193nm immersion lithography. The reversal of the MEEF was clearly observed, especially in the presence of a dipole. When the feature size decreased to the resolution limit, the MEEF rose enormously. Simulations also show that the MEEF is inversely proportional to the cubic root of image contrast in most cases in this study.