Study on Change in UV Nanoimprint Pattern by Altering Shrinkage of UV Curable Resin

Pattern width shrinkage in UV nanoimprint is a basic characteristic which must be fully understood when working with this technology. However, the characteristics of fine structures in the realm of sub-100 nm features remain to be understood. It has been difficult to determine the pattern shrinkage by a simple comparison between mold groove width and UV nanoimprint pattern width. Hence, instead of such a comparison, we compared UV nanoimprint patterns made of the same material but with different shrinkage ratios by altering the ambient in the imprinting space using air and pentafluoropropane (PFP). UV nanoimprint in air and PFP was carried out using the UV curable resin PAK-01 and the widths of the fabricated patterns were precisely determined from scanning electron microscopy (SEM) images using an edge detection program. The differences between the widths of patterns fabricated in air and PFP were found to be 6.0, 8.4, and 11.1 nm for nominal pattern widths of 45, 65, and 90 nm, respectively. The width shrinkage ratio for UV nanoimprint in PFP was estimated to be 14% regardless of pattern width and the figure reasonably agreed with the 11% shrinkage predicted by simulation.