Mitigating pattern collapse in high-resolution extreme ultraviolet lithography using the organic dry development rinse process

Abstract

Pattern collapse emerges as a key factor leading to the failure of photoresist patterns in high-resolution extreme ultraviolet lithography (EUVL). Its significance escalates as feature sizes decrease and pitches become smaller, transitioning to high-numerical aperture extreme ultraviolet, potentially leading to challenges with regard to resolution. Pattern collapse arises from capillary forces acting on the resist surface during wafer drying. Consequently, the optimal strategy to mitigate pattern collapse involves eliminating any drying steps post-lithography processing. We introduce the organic dry development rinse (O-DDR) process for spin-on metal oxide resist, effectively eliminating capillary force and eradicating the pattern collapse issue without tone inversion. This involves dispensing O-DDR material instead of employing a spin-drying developer, without introducing any extra processing steps. After the dry etching process, we observe that the resist patterns, such as pitch 32-nm pillars and pitch 28-nm line and space, appear to have mostly no collapse at small pitches or low doses. Furthermore, we analyze the O-DDR process, intending to expand the window for a failure-free process with pitch 32-nm pillars and pitch 28-nm line and space in EUVL.