High and Hyper NA Immersion Lithography using Advanced Patterning Film APF TM

The objective of this work is to enable the manufacturing of features with most aggressive pitches available to date using APF as a strippable hard mask (HM). Essential for the capability of printing small and in particular dense features is the control of optical reflections during exposure. This is achieved through control of the optical parameters of the used films. The considered optical parameters are the complex reflection coefficient (ntilde = n - ik) and thickness. The angle of incidence of the exposing light when using high or hyper NA (numerical aperture) lithography is no longer negligible. As a consequence the optimum film thickness corresponding to the lowest reflection varies with the pitch of the features being imaged. In this paper we discuss the results based on a hyper-NA simulation illustrating the complexity of such an optimization process. Furthermore we discuss various high-NA simulations and corresponding physical experimental work confirming the validity of this approach