Evaluation of High and Low Activation Resists for EUV Lithography

Abstract

This paper reports our latest findings on the performance of high and low activation resists for EUV lithography. Both low and high activation resists show good capability down to 35 nm resolution, with acceptable LER and photospeed. These resists also show minimal outgassing of 3.4 x 10¹² molecules/cm² outgassed at EUV exposure, well below the maximum outgassing threshold. The best resist material found so far is a blend of high and low activation resist polymers. This material showed resolution to 32nm, photospeed of 18mJ/cm², with an acceptable process window at 35nm. The PEB sensitivity was extremely low, 0.25nm/°C. This resist also had minimal LER, 3σ, of 3nm for 40nm 1:1 lines and spaces.