Resolution enhancement in optical lithography with chromium wire-grid polarization mask

Abstract

Polarization effects have only recently been considered an issue that is growing more for optical lithography. It has been demonstrated that wire-grid structures placed within features have the ability to polarize incident light on a mask. This paper also recognizes the advantages that can be gleamed from the polarization properties, but differs in that it attempts to use a chromium wire-grid polarization mask itself to polarize the incident light. In this paper, we explore a vector model of microlithography imaging with polarization distribution function. Polarization from chromium wire-grid polarization mask can be used as a new lever to improve lithographic performance. This paper also addresses the fundamental issues underlying the design of such a chromium wire-grid polarization mask. The influence of a chromium wire-grid polarization mask on microlithography system has been systematically investigated by comparison on the imaging contrast and the process window. We compare the effects of polarization light imaging with a conventional mask and a chromium wire-grid polarization mask at wavelength of 0.248 m , a numerical aperture of 0.65 and a partial-coherence of 0.2. It can be concluded that a high-resolution imaging performance can be obtained by using chromium wire-grid polarization mask.