High-performance 193-nm photoresist materials based on a new class of polymers containing spaced ester finctionalities

Abstract

ArF lithography has been selected as the imaging method for the 90 nm technology node. Manufacturing related issues will have to be addressed when designing advanced 193 nm resists that are production worthy. Post exposure bake (PEB) sensitivity, dissolution properties and process window are some issues that need continuous improvement. Initially our investigation focused on a cyclic olefin (CO) platform which led us to a better understanding of the relationship between polymer structure and physical properties and how to improve cyclic olefin resist performance. Since then we have developed a new class of acrylate polymers with pendant “spaced ester” functionality. We have investigated the potential use of “spaced ester” functionality on improving the lithographic performance of CO and acrylate resist platforms. We have found that with “spaced ester” as pending group in CO polymer structures, it can lower the Tg and improve the dissolution properties of the CO resists. Resists formulated with acrylate containing “spaced ester” group exhibit excellent PEB temperature sensitivity (1 nm/°C), and are soluble in PGMEA. In addition, we have demonstrated sub-100 nm resolution with excellent process window through formulation optimization for acrylate based resists. This paper will focus on the “spaced ester” based polymer design, material properties; resist characteristics, and the lithographic performance for logic dense line applications.