Journal of Vacuum Science & Technology B, Vol.26, No.6, 2410-2415, 2008
Full field imprint masks using variable shape beam pattern generators
Imprint lithography has been included on the ITRS lithography roadmap at the 32, 22, and 16 nm nodes. Step and flash imprint lithography (S-FIL (R)) is a unique method that has been designed from the beginning to enable precise overlay for creating multilevel devices. A photocurable low viscosity monomer is dispensed dropwise to meet the pattern density requirements of the device, thus enabling imprint patterning with a uniform residual layer across a field and across entire wafers. Further, S-FIL provides sub-100-nm feature resolution without the significant expense of multielement, high quality projection optics, or advanced illumination sources. However, since the technology is 1X, it is critical to address the infrastructure associated with the fabrication of templates. For device manufacturing, one of the major technical challenges remains the fabrication of full field 1X templates with commercially viable write times. Recent progress in the writing of sub-40-nm patterns using commercial variable shape e-beam tools and nonchemically amplified resists has demonstrated a very promising route to realizing these objectives, and in doing so, has considerably strengthened imprint lithography as a competitive manufacturing technology for the sub-32-nm node. Here the authors report the first imprinting results from sub-40-nm full field patterns, using Samsung's current flash memory production device design. The fabrication of the template is discussed and the resulting critical dimension control and uniformity are reported. A second experiment has also demonstrated feasibility for resolving several types of features at half pitches of 32 nm.