Mass production of 193-nm immersion lithography has been started. Top coat process is one of the practical solutions for
applying the conventional dry ArF resists to achieve low material leaching and good scanning property, etc... At the
present, the lithographic world requires non-topcoat process from the point of view of C.O.O. (cost of ownership),
however there are still concerns that have to be revealed and solved. In order to achieve higher scan speed, the superior
water repellent property is required at the surface of non-topcoat resist. On the other hand, the influence of water
repellent surface property to the track process has to be considered. In this report, the considered items (coating,
development, etc...) of the higher water repellent property in non-topcoat process were extracted. Material design for
optimization of surface property with JSR non-topcoat resist and novel rinse method from process were proposed as
solutions to the concerns. Optimization of surface property showed positive impact to the development and defect
performance. The novel rinse method "ADR" which has been developed by Tokyo Electron showed superior availability
to reduction of blob type defect.
It has been found that 193nm immersion lithography technology can achieve smaller patterns without any
modification to the technology infrastructure of existing state-of-the-art 193nm dry lithography. This has made 193nm
immersion lithography a promising technology for mass production processes. Recently, scanning speed of the exposure
stage has been increasing in order to achieve high throughput for mass production. At present, the adoption of a topcoat
is one of the promising candidates for this high speed scanning process. On the other hand, the demand for a non-topcoat
process is being pursued from a C.O.O. (cost of ownership) point of view but there are still issues being revealed and
concerns to be solved. In this report, feasibility of a comprehensive process for high scanning ArF immersion lithography was discussed. As for the topcoat process, a high receding contact angle topcoat, such as TC-A (JSR), is proving to be a good candidate for mass production using high scanning speed immersion lithography. TC-A has a similar defectivity and lithographic performance to TCX041 (JSR). On the other hand, the feasibility of a non-topcoat process was also investigated. CD uniformity, defectivity and lithography performance of AIM5120JN and AIM5570JN (JSR) data indicate that the non-topcoat process can be adopted for mass production process. An immersion cluster comprised of a high volume production immersion exposure tool, S610C (NIKON) having 1.3 NA and CLEAN TRACKTM LITHIUSTM i+ (TEL) track system were used in this study.
EUV exposure is crucial to evaluate EUV resists but there are currently a limited number of EUV exposure tools available worldwide. Therefore, an alternative exposure method should be considered to accelerate EUV resist development. To design materials for EUV resist, it is useful to identify and characterize acid generation mechanisms under EUV exposure. To do this, a performance comparison under EUV, EB and KrF exposure was performed to gather information about the acid generation mechanism during EUV exposure. In this paper, the performance of chemically amplified resists under EUV, EB and KrF was compared regarding sensitivity, LWR and pattern-profile not only to consider alternative exposure methods but also to elucidate the acid generation mechanism under EUV exposure. Regarding sensitivity, good correlation was observed between EUV and EB exposure, however, in regard to LWR and resist pattern profile, poor correlation was observed between EUV and EB exposure, and between EUV and KrF exposure. As a result, alternative exposure methods could be used only for basic evaluation and it was determined that EUV exposure was necessary for EUV resist development using chemically amplified resist. From the correlation of sensitivity between EUV and EB exposure, it is suggested that the main acid generation mechanism under EUV exposure was ionization.