Asymmetric fluid-structure dynamics in nanoscale imprint lithography

developed in efforts to reduce current line widths. X-ray and EUV offer an orderof magnitude potential improvement in line widths.While some of the processes currently in development have demonstratedthe ability to resolve sub-100 nm features in the laboratory, there are technicaland cost considerations that must be overcome to realize their potential benefits.These processes require optical exposure systems that are rare and expensive.Also, x-ray lithography requires a helium atmosphere and x-ray masks havestability problems. Furthermore, these processes have throughput problems. Theeffects of wave diffraction, interference, resist sensitivity, and standing waveeffects limit these optical lithography techniques [Chou, Krauss, and Renstrom1996]. Furthermore, there is the problem of resist transparency as materials thatare transparent to DUV light are opaque to EUV and x-ray regions. With many ofthese issues unresolved, it is near certainty that optical methods will not beadequate for nanoscale (below 100 nm) lithography [Whidden et al. 1996].High-energy particle lithography schemes such as electron beam (E-beamdirect write/project) and ion beam lithography that have been used to producehigh-resolution patterns, and is used to write and repair photomasks. However,for wafer processing, they have problems with cost and throughput. Thesesystems operate serially and cannot maintain the level of throughput required foreconomic manufacture of circuits. Furthermore, there exist proximity effects dueto elastic and inelastic particle collisions. These are referred to as forwardscattering in the photoresist and backscattering from the substrate. Thesefundamental technical challenges and high cost clearly necessitate the search forlow cost, high-throughput alternatives to optical lithography. SFIL is one suchprocess that has demonstrated the generation of sub 100 nm features.7