Proceedings Article | 27 March 2017
Michael Carcasi, Seiji Nagahara, Gosuke Shiraishi, Tomohiro Iseki, Yukie Minekawa, Kosuke Yoshihara, Hisashi Nakagawa, Takehiko Naruoka, Tomoki Nagai, Akihiro Oshima, Seiichi Tagawa
Proc. SPIE. 10143, Extreme Ultraviolet (EUV) Lithography VIII
KEYWORDS: Lithography, Light sources, Polymers, Ultraviolet radiation, Chemistry, Extreme ultraviolet, Extreme ultraviolet lithography, Chemical reactions, Picosecond phenomena, Line edge roughness, Floods, Industrial chemicals, Absorption, Chemically amplified resists
Extreme ultraviolet lithography (EUVL, λ = 13.5 nm) continues to be one of the most important candidates for future technology nodes. For the insertion of EUV lithography into device mass production, higher sensitivity of EUV resists is helpful for better cost of ownership of the EUV tool and light source. However, obtaining low sensitivity (S), high resolution (R), and low line edge roughness (L) simultaneously is very difficult. Many previous experiments by lithographers proved the existence of this "RLS trade-off"<sup>1-2</sup>. This paper furthers the work related to <i>Photosensitized Chemically Amplified Resist</i><sup>TM</sup> (PSCAR)<sup>TM**</sup>, a chemistry which is trying to break the "RLS tradeoff" relationship. This chemistry was introduced as a new chemically amplified lithographic concept and is accomplished in an in-line track tool with secondary exposure module connected to EUV exposure tool. <p> </p>PSCAR is a modified CAR which contains a photosensitizer precursor (PP) in addition to other standard CAR components such as a protected polymer, a photo acid generator (PAG) and a quencher. In the PSCAR process, an improved chemical gradient can be realized by dual acid quenching steps with the help of increased quencher concentration. The addition of the PP, as well as other material optimization, offers more degrees of freedom for getting high sensitivity and low LER, but also makes the system more complicated. Thus coupling simulation and experimentation is the most rational approach to optimizing the overall process and for understanding complicated 2-D structures.<p> </p> In this paper, we will provide additional background into the simulation of PSCAR chemistry, explore the effects of PSCAR chemistry on chemical contrast of complex structures (e.g. T structures, slot contacts, I/D bias for L/S), and explore the sensitivity enhancement levels capable while improving or maintaining lithographic performance. Finally, we will explore modifications of PSCAR chemistry on performance.
