발간논문

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Beyond extreme ultraviolet lithography (BEUVL) is considered to be a future patterning technology using light source with wavelength of 6.7 nm. However, it is difficult to optimize the material system for BEUV mask consisting of reflector and absorber design with an optimized multilayer mirror and absorber layer of the reflective mask. In this study, we propose a lanthanum nitride/boron (LaN-/B) Bragg reflector for 6.7nm through optical simulation. Instead of BEUV absorber, we propose 6% attenuated phase shifting absorber stack to utilize 180 degrees phase shift effect at the edge of pattern. For the absorber stack, we used tantalum nitride (TaN)/ palladium (Pd) and tantalum nitride (TaN)/ ruthenium (Ru). As a result, the BEUV mask with optimized reflector and attenuated phase shifting absorber is expected to exhibit a better imaging performance (i.e., higher normalized image log slope and reduced mask shadowing effect) under 6.7nm illumination compared to the conventional binary intensity mask. †(Received March 24, 2016)

keyword : ceramics, deposition, optical properties, computer simulation, BEUV phase shift mask

Both the deformation behaviors and the associated structural evolution of an Al nanowire were observed by conducting tensile testing in TEM. The Al nanowire exhibited a strength close to the theoretical value and a substantial elastic limit of ~5%. Different from bulk-forms of Al, the Al nanowire did not exhibit any quantifiable plastic strain and failed in a brittle manner. This behavior was related to the formation of deformation twins that interlock. Comparative studies were also performed using an Au nanowire to elucidate the effect that the magnitude of the stacking fault energy (SFE) has on the formation of the deformation twins and plasticity. (Received April 28, 2015)

keyword : nanostructured materials, twinning, nanowires, deformation, transmission electron microscopy, TEM