Advances in Metal-based Photoresist Materials for EUV Lithography and Lithographic Mechanisms

Abstract

With the rapid development of IC industry, lithography, as a key step in IC manufacturing, is facing challenges in various aspects, such as the light source, photomask and photoresist. EUVL, which uses extreme ultraviolet light at 13.5 nm, has higher photon energy, and puts forward higher requirements for photoresist materials. Metal-based photoresists are key materials in EUVL due to their excellent light absorption ability, high resolution and etch resistance. Metal-based photoresists mainly include metal elements such as Sn, Zr, Hf, and Zn, which exhibit extremely high light absorption cross-section at 13.5 nm wavelengths, and are able to effectively improve the sensitivity and resolution of photoresists. This review discusses in detail the research progresses and solubility switch mechanisms of different metal-based photoresists, such as carbon-tin bond breaking in tin-based photoresists, ligand exchange and polarity shift in zirconium- and hafnium-based photoresists. The review discusses the design strategies of metal-based photoresists, including the optimization of photoresist properties by tuning the ligands and core structures of metal nanoclusters and the research direction of metal-based small molecule photoresists. In addition, this review also presents some innovative studies. Although the development of metal-based photoresists still faces challenges such as unclear photochemical reaction mechanisms, photonic randomness and chemical randomness. Through multidisciplinary cross-collaboration, metal-based photoresists are expected to make greater breakthroughs in the field of EUVL and promote the sustainable development of the IC industry.