Development of Low Line Edge Roughness and Highly Sensitive Resist for Extreme Ultraviolet Lithography

Abstract

We developed a novel chemically amplified resist to increase sensitivity and reduce line edge roughness (LER) in extreme ultraviolet (EUV) lithography. This resist consists of a base resin of which a photochemical acid generator (PAG) is bonded to the side chain this is called the PAG-bonded resist. Under EUV exposure, an E0 sensitivity of 1.9 mJ/cm2 and a low outgassing pressure of 2.5×10-6 Pa were achieved. Resolution and LER were obtained by electron beam (EB) exposure. Under EB exposure, an LER of 2.1 nm (3σ) for a 100 nm line and space (L/S) pattern was achieved by the PAG-bonded base resin. In addition, we improved this resist and an LER of 4.0 nm (3σ) for a 50 nm L/S pattern was achieved under EB exposure. These results demonstrate that the novel resist system has a good advantage in terms of high sensitivity and low LER.