The demand to rapidly and economically fabricate nanoscale structures is a major driving force in the development of nanoscience and nanotechnology. Nanoimprint lithography (NIL), also known as hot embossing lithography, in which a thickness relief is created by deforming a polymer resist through embossing with a patterned hard mold, offers several decisive technical advantages, in particular as a low-cost method to define nanoscale patterns. Although there are a number or nanoimprinting techniques presently available, these techniques are strictly limited by the temperature and/or pressure required by the technique, as well as the type of substrate used in the technique.
Inventors at the University of Michigan have developed a new imprinting technique that is adaptable for many different substrates and substrate configurations. This reversal imprint process proceeds by transferring a spin-coated polymer layer from the hard mold to the substrate. Three different pattern transfer modes (embossing, inking and whole-layer transfer) can be accomplished by controlling imprinting temperature and degree of surface planarization of the spin-coated mold. Either a positive or negative replica of the mold can be obtained after imprinting. With a suitable degree of surface planarization, successful pattern transfer can be achieved at temperatures and pressures as low as 30°C below Tg and 1 MPa, respectively, in the inking and whole-layer transfer modes.
Applications and Advantages
- Nanoimprinting of three-dimensional-nl-structures/non-planar surfaces
- Complex micro-devices
- Can be carried out under lower temperatures-nl-and pressures
- Allows imprinting onto non-planar substrates-nl-and substrates that cannot be easily-nl-spin-coated with a polymer film