Details of a mix and match process of thermal nanoimprint lithography and UV lithography have been investigated, where the smaller patterns were defined by imprint, whereas the larger patterns were prepared by UV lithography within the same layer of negative tone resist. Stabilization of the prepatterned resist after imprint by UV curing within the open windows of a mask is different from stabilization under flood exposure. In addition to reflection at the substrate, which leads to a height dependent, vertically modulated exposure dose pattern, the pattern edges, due to diffraction effects, result in an additional lateral modulation of the exposure dose. Distinct local intensity minima and maxima develop within the resist. The intensity differences are particularly strong in the case of pattern widths in the wavelength dimension. Furthermore the direction of light polarization affects the exposure dose pattern. In the case of pattern widths well above the wavelength mainly an underexposure along the edges of the prepatterned layer remains, indepenent of the polarization direction. The authors found that, under exposure conditions best suited for UV lithography, the stabilization of a prepatterned layer remains incomplete. Full stabilization requires overexposure on the cost of resolution of the UV lithography and edge steepness of the lithographically defined patterns. (c) 2006 American Vacuum Society.