27 March 2017 Simulation and experimentation of PSCAR chemistry for complex structures
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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"1-2. This paper furthers the work related to Photosensitized Chemically Amplified ResistTM (PSCAR)TM**, 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.

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.

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.
© (2017) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Michael Carcasi, Michael Carcasi, Seiji Nagahara, Seiji Nagahara, Gosuke Shiraishi, Gosuke Shiraishi, Tomohiro Iseki, Tomohiro Iseki, Yukie Minekawa, Yukie Minekawa, Kosuke Yoshihara, Kosuke Yoshihara, Hisashi Nakagawa, Hisashi Nakagawa, Takehiko Naruoka, Takehiko Naruoka, Tomoki Nagai, Tomoki Nagai, Akihiro Oshima, Akihiro Oshima, Seiichi Tagawa, Seiichi Tagawa, } "Simulation and experimentation of PSCAR chemistry for complex structures", Proc. SPIE 10143, Extreme Ultraviolet (EUV) Lithography VIII, 1014329 (27 March 2017); doi: 10.1117/12.2258166; https://doi.org/10.1117/12.2258166

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