Reactive fluorinated surfactant for step and flash imprint lithography

One of the major concerns with nanoimprint lithography is defecivity. One source of process specific defects is associated with template separation failure. The addition of fluorinated surfactants to the imprint resist is an effective way to improve separation and template lifetime. This study focuses on the development of new reactive fluorinated additives, which function as surfactants and also have the ability to chemically modify the template surface during the imprint process and thereby sustain a low surface energy release layer on the template. Material screening indicated that the silazane functional group is well suited for this role. The new reactive surfactant, di-(3,3,4,4,5,5,6,6,7,7,8,8,8- tridecafluorooctyl)silazane (F-silazane) was synthesized and tested for this purpose. The material has sufficient reactivity to functionalize the template surface and acceptable stability (and thus shelf-life) in the imprint formulation. Addition of F-Silazane to a standard imprint resist formulation significantly improved template release performance and allowed for significantly longer continuous imprinting than the control formulation. A multiple-imprint study using an Imprio® 100 tool confirmed the effectiveness of this new additive.