Full field imprinting of sub-40 nm patterns

摘要

Imprint lithography has been included on the ITRS Lithography Roadmap at the 32, 22 and 16 nm nodes. Step andFlash Imprint Lithography (S-FIL ) is a unique patterning method that has been designed from the beginning to enableprecise overlay to enable multilevel device fabrication. A photocurable low viscosity resist is dispensed dropwise tomatch the pattern density requirements of the device, thus enabling patterning with a uniform residual layer thicknessacross a field and across multiple wafers. Further, S-FIL provides sub-50 nm feature resolution without the significantexpense of multi-element projection optics or advanced illumination sources. However, since the technology is 1X, it iscritical to address the infrastructure associated with the fabrication of imprint masks (templates). For sub-32 nm device manufacturing, one of the major technical challenges remains the fabrication of full-field lximprint masks with commercially viable write times. Recent progress in the writing of sub-40 nm patterns usingcommercial variable shape e-beam tools and non-chemically amplified resists has demonstrated a very promising routeto realizing these objectives, and in doing so, has considerably strengthened imprint lithography as a competitivemanufacturing technology for the sub-32nm node. Here we report the first imprinting results from sub-40 nm full-fieldpatterns, using Samsung's current flash memory production device design. The fabrication of the imprint mask and theresulting critical dimension control and uniformity are discussed, along with image placement results. The imprintingresults are described in terms of CD uniformity, etch results, and overlay.