Non Topcoat Self-freezing Photoresist for Double Patterning Process

Double patterning is one of the most promising techniques for sub-30nm half pitch device manufacturing. Several techniques such as dual-trench (litho-etch-litho-etch: LELE) and dual-line (litho-litho-etch : LLE) have been reported. Between them, the dual-line process attracts a great deal of attention due to its higher throughput. The key issue in the dual-line process is preventing damage of the first resist pattern during the second lithography process. As a solution, we have developed a process to alleviate this issue using a chemical material called "freezing agent." More recently, we have further simplified the process by developing a simple freezing technique called "self-freezing". The "self-freezing resist" material can accomplish the freezing process by applying only one bake to the resulting first pattern. In addition, our self-freezing resist also has added water shedding properties to meet non-topcoat (non-TC) immersion resist requirements, which further simplifies the process and materials. In this study, imaging results of Non-TC self-freezing resist including critical dimension uniformity (CDU), defectivity and processing properties of the resulting patterns is shown.