Throughput of Ultraviolet Nanoimprint in Pentafluoropropane Using Spin Coat Films under Thin Residual Layer Conditions

Abstract

In UV nanoimprint, UV-curable resin is usually supplied as droplets, but, from the viewpoint of throughput, it is not the best approach in some cases. When the pattern density of a given layout can be regarded as uniform, UV-curable resin should be supplied as a film with a uniform thickness if no other critical problems occur. Fine line-and-space (L/S) patterns with widths of 45, 65, and 90 nm were successfully fabricated with a residual layer thickness of 20 nm by UV-NIL in pentafluoropropane (PFP) using a spin coat UV-curable resin, PAK-01, and the throughput of UV-NIL in PFP for the fabrication of such fine L/S patterns with a thin residual layer was investigated. The resin filling of UV-NIL in air was not completed in 15 s but that of UV-NIL in PFP was completed in 0.6 s. The filling speed of UV-NIL in PFP is 80 times higher than that of UV-NIL in air. This value is one order of magnitude larger for the fabrication of patterns with a width of 300 µm in our previous work, and the high-throughput process is presumably due to the large capillary pressure, which may be canceled out for UV-NIL in air, of fine grooves of the L/S patterns. Simulation revealed that a virtual imprint pressure of 2.2 MPa should be produced by the capillary pressure for UV-NIL in PFP. Simulations also revealed that the complete filling time is proportional to the square of the space width and that the resin filling would be completed in 0.1 s for a space width of less than 40 µm.