Characterization of metal resist for EUV lithography using Infrared free electron laser

We characterized the reactivity of a model metal resist for extreme ultraviolet (EUV) lithography by using a midInfrared free electron laser (mid-IR FEL). The evaluated metal resist consisted of a zirconium-oxide core and methacrylic-acid (MAA) ligands. The mid-IR spectra of the metal resist were measured to study photoresponse to FEL irradiation. In the spectra, the metal resist exposed with EUV light showed decreases of peaks of MAAs coordinating a metal core and new peaks have emerged. Mid-IR FEL study suggested that the EUV exposure made ligands of the metal resist more reactive, which are possible pointers increasing the sensitivity of the metal resist.