We report advances in nanoimprint lithography, its application in nanogap metal contacts, and related fabrication yield. We have demonstrated 5 nm linewidth and 14 nm linepitch in resist using nanoimprint lithography at room temperature with a pressure less than 15 psi. We fabricated gold contacts (for the application of single macromolecule devices) with 5 nm separation by nanoimprint in resist and lift-off of metal. Finally, the uniformity and manufacturability of nanoimprint over a 4 in. wafer were demonstrated.The field of nanotechnology is advancing rapidly. Applications of nanotechnology include subwavelength optical elements, biochemical analysis devices, photonic crystals, high-density single-domain magnetic storage, and singlemolecule devices, to name a few. Yet, key to the commercial success of these nanotechnology applications are low cost and high throughput manufacturing capabilities. State-of-theart manufacturing photolithography patterning tools are both too expensive and incapable of producing the necessary pitch and feature sizes of these applications. Thus, presently, researchers have been largely constrained to using lowthroughput lithography tools, such as electron-beam lithography (EBL), atomic force microscopy (AFM), and ion-beam lithography. For high-throughput and low-cost lithography, various "nanoprinting" technologies have been developed. 1-3 Here, we report our investigation of the resolution limit of nanoimprint lithography, where we demonstrated a nanoimprint record of 5 nm linewidth features and 14 nm pitch over a large area, its applications in nanogap metal contacts, and a study of fabrication yields.In photocurable nanoimprint lithography (P-NIL) (shown in Fig. 1), a mold is pressed into a low viscosity photocurable resist liquid to physically deform the resist shape such that it conforms to the topology of the mold. The resist is cured with exposure to UV light, crosslinking the various components in the resist liquid, producing a uniform, relatively rigid polymer network. The mold is then separated from the cured resist. Finally, an anisotropic reactive ion etch (RIE) removes the residual resist in the compressed area, exposing the substrate surface.In order to explore the performance of P-NIL, a variety of molds were fabricated to test specific attributes, including minimum pitch (maximum density), minimum feature size, and large-area uniformity patterning. Previously, 10 nm dots and 40 nm pitch have been demonstrated by NIL 1 with the resolution limited by our ability to fabricate the mold, as proximity effects inherent with EBL make sub-35 nm pitch patterning very difficult. To produce a mold with a pitch resolution surpassing EBL capabilities, we fabricated a NIL mold by selectively wet etching Al 0.7 Ga 0.3 As from a cleaved edge of a GaAs/ Al 0.7 Ga 0.3 As superlattice [grown by molecular-beam epitaxy (MBE)] with a dilute solution of hydrofluoric acid (HF). 4,5 This mold fabrication process offers many advantages, specifically very dense sub-50 nm pitch topologies can be ...