Nanoimprint lithography is a technique used to create nanoscale patterns, and has been explored in a wide variety of applications. Unlike some of the current photolithography techniques which can achieve small patterns but are cost-inhibitive for mass production, imprinting techniques are simpler, faster, and are less expensive for processing. In addition, imprinting can lend itself to the fabrication of 3-dimensional (3D) features, which may be an important enabling technology for a number of applications. However, the nanoimproint lithography techniques to date create 3D structures through multiple imprinting on patterned substrates or on substrates with topology, which may not be amenable for mass production.
Researchers at the University of Michigan have developed a duo-mold imprinting process that produces supported and free-standing 3D features on a micro- or nanoscale. The approach uses surface treatments to impart differential surface energies to different molds and/or different parts of the molds to allow formation of 3D structures through imprinting and the transfer of such structures to a substrate. The surface treatments and variation in glass transition temperature of the polymers used can facilitate separation of the 3D structures from the molds to form free-standing structures individually and/or in a film. In addition, a “latch-on” assembly technique is utilized to form supported and/or free-standing stacked structures that enable the assembly of polymers without a glass transition temperature and eliminate heating required to assemble thermoplastic polymers.
Applications and Advantages
- microprocessors: increased speed and memory
- optoelectronics: minimization of the-nl-loss of light
- drug delivery/ chemical sensing: enhanced-nl-efficiency and selectivityAdvantages
- higher resolution over conventional-nl-photolithography
- low cost and can be implemented for mass-nl-production; may replace photolithography