The study of phase angle effects to wafer process window using 193-nm EAPSM in a 300-mm wafer manufacturing environment

As the semiconductor-process technology advances towards the 90nm-node, more and more wafer-fabs start to use 193nm EAPSM (Embedded Attenuated Phase-Shift Mask) technology as the main lithography strategy for the most critical-layers. Because the 193nm EAPSM is a relative new technology in the semiconductor industry, it is important for us to understand the key-mask-specifications in a 193nm EAPSM and their impact to the wafer process windows. In this paper, we studied the effects of phase-angle and transmission to the wafer process window of a 193nm-EAPSM in a 300mm wafer-manufacturing environment. We first fabricated a special multi-phase EAPSM by a combination of extra Quartz-etch and Mosi-removal. We then used a high NA 193nm scanner (ASML-ALTA1100) and high contrast resist to perform the wafer-level printing study. To fully understand the impact of phase-angle and transmission to wafer process windows, we also used AIMS (Aerial-Image Measurement System) and Prolith simulation software to study the lithographic performances of various phase-angle and transmission combinations. By combining the wafer-level resist imaging printing results, AIMS studies and Prolith-2 lithography simulations, we proposed the practical phase-angle and transmission specifications for the 90nm-node wafer process.