Simulation of Applications of High-Transmittance Embedded Layer in Transmittance Control Mask and Optimization of Attenuated Phase-Shifting Mask by Design of Experiment

概要

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The applications of a high-transmittance embedded layer (HTEL) ($T=15--35$%) in an attenuated phase-shifting mask were studied by simulation with the aid of Taguchi design of experiment. A modified transmittance control mask with HTEL was proven to be useful in preventing photoresist bridging between two adjacent contact holes on a wafer. The optimal trnasmittance ($T$) was determined to be 30–35%. With optimization, the optimized results of the fabrication of a 45 nm isolated line using a 193 nm wavelength light source in the immersion mode indicated that the exposure latitude (EL) increases from 1.20 to 1.31 mJ/cm2 with the following settings: HTEL $T$ of 35%, annular off-axis illumination (OAI) $\sigma_{\text{outer}}$ of 0.7, $\sigma_{\text{inner}}$ of 0.4, and numerical aperture (NA) of 1.152. For the optimization of the fabrication of 70 nm iso-dense lines, the simulation results showed that EL increases from 2.21 to 2.30 mJ/cm2 with the following settings: HTEL $T$ of 25%, dipole OAI $\sigma_{\text{center}}$ of 0.6, $\sigma_{\text{radius}}$ of 0.2, and NA of 1.224.
Published by the Japan Society of Applied Physics through the Institute of Pure and Applied Physicsの論文
2007-01-15