17 April 2014 OBPL for the best solution to resist outgassing and out-of-band issues in EUVL toward 1Xnm hp
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Extreme-UV lithography (EUVL) is the most promising candidate of next generation technology for hp20nm node device manufacturing and beyond, however there are many critical issues to solve in the light source, tools, mask and photo resist. Regarding the development of a photo resist, it is necessary for high volume manufacturing (HVM) to improve LWR, resolution limit and sensitivity. Additionally, concerning about deterioration of a patterning performance by Out-of-Band (OoB) light existing in the EUV light, and contamination problem of exposure tool due to the photo resist outgassing are the key issues which have to be resolved toward HVM by EUVL. Especially, the outgassing problem can become a significant issue for fine patterning under high dose exposure condition. This paper proposes the novel solution for these critical issues with the application of a top coat material which is named OBPL (Outgassing & out-of-Band Protection Layer) on photo resist. The key characteristics of OBPL material are to have a role in protection against the OoB adverse effect to keep up the photo resist performance, to suppress the outgassing from photo resist as a barrier layer and to enhance the lithographic performance such as photo resist profile and process window. In designing the OBPL material, the optical property needs having not only the high absorbance of DUV (Deep-UV) light in OoB range but also high transmittance for 13.5nm wavelength to prevent the sensitivity loss. Furthermore, it is found that the polymer backbone affects the outgassing barrier capability in previous evaluation. Based on these investigations, a state-of-the-art OBPL achieves quite a positive lithographic result with sufficient OoB absorption and outgassing suppression. Moreover, this material has applicability to all types of photo resist including NTD (Negative-Tone Development) process. This paper describes the result of the feasibility study for OBPL and the lithography performance with EUV full field scanner.
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Noriaki Fujitani, Noriaki Fujitani, Rikimaru Sakamoto, Rikimaru Sakamoto, Takafumi Endo, Takafumi Endo, Hiroaki Yaguchi, Hiroaki Yaguchi, Ryuji Onishi, Ryuji Onishi, "OBPL for the best solution to resist outgassing and out-of-band issues in EUVL toward 1Xnm hp", Proc. SPIE 9048, Extreme Ultraviolet (EUV) Lithography V, 90482H (17 April 2014); doi: 10.1117/12.2046244; https://doi.org/10.1117/12.2046244

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