For advanced node such as 14nm technology and beyond, Patterning is one of the key challenges in the semiconductor industry. Advanced pattern transfer techniques such as negative tone development (NTD) technology are under investigation to enable the aggressive pitch requirements demanded. Even though, just as traditional positive tone development (PTD) technique, a pattern wiggling issue has arisen with the reduction of pattern dimension during dry etch process, which prevents the successful pattern transfer [1].
Two kinds of wiggling solutions have been proposed. One is the lithographic resolution such as changing the physical properties of the under-layer materials [2-4]. The other is the gases treatment in the tri-layer process such as H2plasma for spin-on carbon (SOC) hard-mask [5] and HBr and Ar plasma treatment for photoresist [6]. However, with the decrease of device size, a single method hardly eliminates wiggling and meets the pattern target. Besides, the requirements for Line Edge Roughness (LER)/Line Width Roughness (LWR); critical dimension uniformity (CDU); through pitch are extremely aggressive in advanced technology. Therefore, the characteristics of the dry etching process play an increasingly import role in defining the outcome of the pattern process.
In this paper, we will demonstrate the method of PR treatment (both PTD and NTD techniques) that improves LER/LWR for trench pattern in dry etch ICP etcher. Meanwhile, the difference of PR treatment methods between PTD and NTD is illuminated. What’s more, in PR treatment methods, other pattern behavers such as CD, CD uniformity, through pitch are concerned during improving LER/LWR process, and aim to get a good result of all aspects. At last, the role of various plasma etch parameters that influence the key patterning metrics of CD, resist selectivity and LER/LWR are studied.
Acknowledgement
REFERENCES
[1] Goji Wakamatsu, Kentaro Goto, Yoshi Hishiro, Taiichi Furukawa al., Advances in Resist Materials and Processing Technology XXIX, Proc. of SPIE Vol. 8325 83250T-1,(2012)
[2] Makoto, M., Mitsuaki, I., Takashi, K., Hisashi, H, and Seiji, F., Proc. SPIE7972,797226 (2011).
[3] Tadokoro M., Yonekura K., Yoshikawa K., Ono Y., Ishibashi T., Hanawa T., Fukiwara N., Matsunobe T., MatsudaK., J. Vac. Sci.Technol. B,26, 67-71 (2008).
[4] Someya, Y., Shinjo, T., Hashimoto, K., Nishimaki, H., Karasawa, R., Sakamoto, R., Matsumoto,T., Proceedings of the SPIE, vol.8325, 83250U (2012).
[5] M. Tadokoro, K. Yonekura, K. Yoshikawa, Y. Ono, T. Ishibashi,T. Hanawa, and N. Fujiwara, J. Vac. Sci. Technol. B 26 (1) Jan/Feb( 2008)
[6] E. Pargon, K. Menguelti, M. Martin, A. Bazin, O. Chaix-Pluchery, C. Sourd, S. Derrough, T. Lill, and O. Joubert, Journal of Applied Physics 105, 094902 (2009)