Directly patterning dielectric insulator materials for semiconductor devices via nanoimprint lithography has the potential to simplify fabrication processes and reduce manufacturing costs. However, the prospect of mechanically forming these materials, especially when they are highly porous, raises concerns about their physical integrity. We report the direct imprinting of 100 nm parallel line-space patterns into a high modulus poly(methylsilsesquioxane)-based organosilicate thin film that is capable, in its non-patterned form, of meeting the ultra-low dielectric constant requirement of k 2.3. Immediately after imprinting a (5 to 10) % shrinkage in the pattern height of the partially vitrified patterns relative to the mold is quantified using X-ray reflectivity.Nanoscopic pores with an average diameter of approximately 2.2 nm are then generated in the patterns at high temperatures, through the volatilization a second phase porogen, while the material simultaneously vitrifies into a glassy organosilicate network. Pattern shape changes upon vitrification are also quntified and indicating that a 12 % reduction in the pattern height of the porogen-loaded imprint is observed with very little change in the pattern width. For a imprint without the added porogen, the shrinkage is still anisotropic in the height direction, but reduced approximately by 4 %. Our results show that nanoporous low-k patterns can be replicated via nanoimprint lithography with very little loss in the pattern quality.
Pub Type: Journals
direct patterning, low-k dielectric, nanoimprint lithography, nanoporous, pattern fidelity, specular X-ray reflectivity