An Evaluation of Ion Implantation for LWR Improvement in EUV Lithography

Abstract

The potentiality of line width roughness (LWR) reduction by ion implantation (I/I) in the extreme ultra violet (EUV) lithography resist pattern was studied. The Argon ions were implanted to the Line-and-Space (L/S) pattern of EUV resist with changing ion energy, dose and incident angle. The LWR and line width of 32 nm half-pitch L/S pattern was evaluated after development, after I/I and after dry etching of the experimental thin hard mask beneath the resist pattern. The LWR of 4.2 nm 3 &sigme;, corresponding to the reduction of 1.6 nm, was obtained for resist after I/I with relatively low energy condition of 1-5 keV. On the other hand, the best value of LWR after hard mask dry etching was 3.6 nm 3σ with I/I energy of 15 keV. It was found that the change of hydrogen content of resist by I/I can be important for the improvement of LWR including etching process.