Narrowband spectrum effect on resolution enhancement for 50-nm pattern printing by proximity x-ray lithography

Proximity x-ray lithography (PXL) technology has already met the specifications required for 100 nm technology node, and it replicated 70 nm pattern with a large latitude. In order to attain the 50-nm resolution and below, the uses of a harder spectrum and the resist materials containing the elements such as Br, F, Si and Cl have been proposed. These elements in the resist are effective to get a high sensitivity and to suppress the influence of the emitted secondary electrons from a Si substrate, as well as to improve the resolution. In addition, the absorbed power spectrum in these resists becomes narrow comparing to the normal one consisted of C, H, and O. In this work, we study the narrowband effect for replicating 50-nm patterns using the normal soft x-ray.