Polarized Phase Shift Mask: Concept, Design, and Potential Advantages to Photolithography Process and Physical Design

摘要

In this paper we introduce a novel phase shift mask technology: Polarized Phase Shift Mask (P:PSM) technology. A polarized phase shift mask modifies not only the intensity and phase of an incident light, but also its polarization properties. The mask contains regions that transmit orthogonally polarized light. Orthogonally polarized light sources do not interfere with each other destructively, and therefore do not create undesired features on wafers, as seen in conventional two-phase PSM technology. Hence P:PSM solves the well-known "phase edge" or "phase conflict" problem. By obviating the 2nd exposure and 2nd mask in current Complementary Phase Shift Mask (C:PSM) technology, this single mask/single exposure technology offers significant advantages towards photolithography process as well as pattern design. We use examples of typical design and process difficulties associated with the C:PSM technology to illustrate the advantages of the P:PSM technology. We present preliminary aerial image simulation results that support the potential of this new reticle technology for enhanced design flexibility. We also propose possible mask structures and manufacturing methods for building a P:PSM.