Effect of molecular layer deposition parameters on the electron beam resist properties of hafnicone hybrid films

To meet increasing computing demands, device manufacturing is transitioning to shorter wavelengths of light for photolithographic patterning of nanoscale devices. The transition to extreme ultraviolet radiation requires new photoresists to achieve efficient and optimal patterning. We developed the molecular layer deposition of hybrid hafnicone films combining Hf with hydroquinone as the organic linker and then investigated their electron beam resist properties as an indicator of extreme ultraviolet resist performance. We also explored the effect of deposition parameters on resist performance. The films were found to be patternable as negative-tone resists in dilute hydrochloric acid. By varying the deposition temperature between 150 and 180 °C, and the pulse and purge times of the tetrakis(dimethylamido)hafnium(IV) precursor from subsaturation to full saturation conditions, the final resist properties could be only moderately tuned. The molecular layer deposition conditions that achieved the best resolution and contrast were found to be the lowest deposition temperature studied and full saturation. However, increasing the deposition temperature improved the resist sensitivity, though at the cost of resolution and contrast. The best sensitivity value of the film was 400 mC/cm2 at a deposition temperature of 180 °C, and the best resolution of 40 nm required a deposition temperature of 150 °C.