Feasibility Study of Chemically Amplified Extreme Ultraviolet Resists for 22 nm Fabrication

Abstract

The trade-off between sensitivity, resolution, and line edge roughness is the most important concern for the development of high-performance resists based on chemical amplification. Below sub-30 nm patterns, a chemical balance between acids and quenchers basically controls the quality of latent images. Under this situation, an ideal chemically amplified resist is the one in which the neutralization between acids and quenchers proceeds before the start of acid catalytic reactions and chemical reactions occur with a diffusion-controlled rate. In this study, the qualities of latent images were compared among exposure doses of 2, 5, 10, and 20 mJ cm-2 under the ideal condition. The authors found that chemically amplified resists with a 22 nm resolution and a 10 mJ cm-2 sensitivity are feasible under the ideal condition. However, a high-quality image is unlikely to be obtained upon 5 mJ cm-2 exposure without increasing polymer absorption or acid generation efficiency per photon.