An electrical defectivity characterization of wafers imprinted with step and flash imprint lithography

For the first time, electrically testable snake and comb structures were used to quantitatively characterize the defectivity associated with imprint lithography, specifically with Step and Flash Imprint Lithography. Whereas the overall yield for quarter micron optically-patterned snakes was found to be approximately 95%, the corresponding value for imprinted snakes was about 84%. The yield of imprinted snakes was found to fall rapidly with decreasing feature size. For example, the yield of 1:5 50 nm short snakes was only about 55%. Complementary optical inspection suggested feature pullout (release agent failure and mechanical layer separation) was a prevailing occurrence. Qualitatively, defects were binned into four primary, broad categories: self-cleaning template defects; non self-cleaning template defects; imprint-impeding defects; and template damaging defects. Additionally, the template cleaning process employed was found to be fairly efficient at removing particles, particularly when considering defects at the larger feature sizes. There is no doubt that the control of defectivity will be the next large hurdle that will challenge imprint lithography as it strives to make inroads in manufacturing arenas. Finally, a future study is planned with improved etch barrier and transfer layers.