Fabrication of Capacity-Equalized Mold for Homogenizing Residual Layer Thickness in Imprint Lithography

Residual layer control is the key issue in imprint lithography. A thin and uniform residual layer is easily realized for uniform pattern density but it is hardly realizable for nonuniform pattern densities where the moldable materials are supplied by spin coating. The author proposes a new type of mold called capacity-equalized mold that homogenizes the residual layer for a variety of pattern densities and is even suitable for spin-coated films. The capacity-equalized mold was fabricated by introducing an additional lithography step to the conventional mold fabrication process by employing a supplementary mask for modulating the cavity depths in molds. The uniform residual layer for a variety of pattern densities was confirmed by UV nanoimprint using a capacity-equalized mold.