이머젼 리소그래피에서 마스크에 의해 유도된 편광에 대한 전산모사

Abstract

The minimum feature size of a semiconductor device will be smaller and smaller because of the increasing demand for high integration of devices. According to a recently proposed roadmap, ArF immersion lithography will be used for 65-nm to 45-nm technology nodes. The polarization effect becomes a more important factor due to the increasing demand for high-NA optical system and to the use of immersion lithography. It is important to know that the polarization effect is induced by mask in small-size patterning. Unpolarized plane waves leaving the illumination system are diffracted by the mask, so the light beam going through the mask will experience polarization induced by the mask. In this paper, we consider the change in the polarization state as a function of the mask properties. We calculated the light diffracted by the mask for 193-nm incident light. The masks considered are a chromeless mask, a binary chrome mask, and a 6 %-attenuated phase-shifting mask. We used the finite difference time domain method to solve Maxwell equations. The aerial image depends on the polarization states induced by mask properties such as the material, the thickness, and the pitch of the mask.