The effect of transmission reduction by reticle haze formation

Abstract

Recently, a pattern size gradually has reduced to enhance the integration of semiconductor device. As minimum line widths have shrunk, the exposure wavelength has also progressively shrunk. The exposure wavelengths have been reduced progressively from 436 nm to 365 nm to 248 nm to 193 nm. Expose wavelength shrink caused some serious problems. One of the problems to be solved is growing defect in the reticle during the process. Reticle growing defect is called a 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 mask by 193 nm laser irradiation. And the thickness is measured by the spectroscopic ellipsometry. This paper describes the relationship between transmittance and the haze formation, photochemical reactions and the haze effect on the process latitude. In addition, throughput is decreased due to haze formation.