Metal oxide resist formulation and process advancements towards high-NA EUV lithography

Metal Oxide Resists (MOR) are uniquely suited to single-patterning EUV lithography in current high-volume manufacturing and for next generation high-NA applications. This suitability — based on a high EUV absorbance, excellent etch selectivity, local uniformity, and track compatibility — has made Inpria MOR a leading candidate for the continued advancement of EUV lithography to meet the needs of semiconductor manufacturers. Through investigation and application of fundamental MOR chemistry, Inpria has made formulation and process improvements to achieve industry targets for current and future technology nodes. Here we describe advancements in metrology to achieve improvements in sensitivity and roughness. We will discuss, in detail, a methodology to evaluate low-frequency line wiggling to use as a metric for continued resist development and advancement. We will also discuss recent materials advancements that enable a positive-tone MOR resist platform and demonstrate quality patterning of hexagonal contact holes down to 32-nm pitch, along with etch pattern-transfer at pitch-38. We will also discuss collaborations that have demonstrated high-NA patterning results, specifically of place-and-route features, down to pitch-18 with pattern transfer. These advancements, taken in aggregate, extend the advantages and progress of MOR development to align with current and future EUV lithography needs for high-volume manufacturing.