High Performance Wire Grid Polarizers Using Jet and Flash™ Imprint Lithography

The ability to pattern materials at the nanoscale can enable a variety of applications ranging from high density data storage, displays, photonic devices and CMOS integrated circuits to emerging applications in the biomedical and energy sectors. These applications require varying levels of pattern control, short and long range order, and have varying cost tolerances. Extremely large area roll to roll (R2R) manufacturing on flexible substrates is ubiquitous for applications such as paper and plastic processing. It combines the benefits of high speed and inexpensive substrates to deliver a commodity product at low cost. The challenge is to extend this approach to the realm of nanopatterning and realize similar benefits. The cost of manufacturing is typically driven by speed (or throughput), tool complexity, cost of consumables (materials used, mold or master cost, etc.), substrate cost, and the downstream processing required (annealing, deposition, etching, etc.). In order to achieve low cost nanopatterning, it is imperative to move towards high speed imprinting, less complex tools, near zero waste of consumables and low cost substrates. The Jet and Flash Imprint Lithography (J-FIL (TM)) process uses drop dispensing of UV curable resists to assist high resolution patterning for subsequent dry etch pattern transfer. The technology is actively being used to develop solutions for memory markets including Flash memory and patterned media for hard disk drives. In this paper we have developed a roll based J-FIL process and applied it to technology demonstrator tool, the LithoFlex 100, to fabricate large area flexible bilayer wire grid polarizers (WGP) and high performance WGPs on rigid glass substrates. Extinction ratios of better than 10000 were obtained for the glass-based WGPs. Two simulation packages were also employed to understand the effects of pitch, aluminum thickness and pattern defectivity on the optical performance of the WGP devices. It was determined that the WGPs can be influenced by both clear and opaque defects in the gratings, however the defect densities are relaxed relative to the requirements of a high density semiconductor device.