The Influence of Transmission Reduction by Mask Haze Formation in ArF Lithography

Abstract

The line width has been gradually reduced to enhance the integration of semiconductor devices. As minimum line widths have shrunk, the exposure wavelength has also progressively shrunk. The exposure wavelengths have been reduced progressively from 436 run to 365 nm to 248 nm and to 193 nm. This shrinkage of the exposure wavelength has caused some serious problems. One of the problems is the growth of defects in the reticle during the process. Such defects in the reticle are called haze. Haze is formed around the pellicle on the quartz side of the mask and on the chrome side of the mask. In this investigation, mask haze is intentionally formed on the backside of a mask by using 193 nm laser irradiation. The mask thickness is measured by using atomic force microscopy and spectroscopic ellipsometry. We investigated the simulated critical dimension value and the throughput by using Solid-E of Sigma-C for each mask. This paper will use simulations to describe the relationship between the transmittance and haze formation, the effect of haze on the process latitude, and throughput reduction due to haze formation. This study will lead to an understanding of the impact of possible limitations of haze transmission on the imaging performance of each mask.