Design strategy of extreme ultraviolet resists

The high-volume production of semiconductor devices with EUV lithography started in 2019. During the development of EUV lithography, the resist materials had always been ranked high in the focus area for its realization. The trade-off relationships between the resolution, line width roughness, and sensitivity were the most serious problem. EUV lithography started with the use of chemically amplified resists after the material chemistry was optimized on the basis of radiation chemistry. The increase of numerical aperture has been scheduled to enhance the optical resolution. For the realization of next-generation lithography, the suppression of stochastic effects is the most important issue. A highly absorptive material is key to the suppression of stochastic effects. The development of next-generation EUV resists has progressed around chemically amplified resists, metal oxide resists, and main-chain-scission-type resists. EUV resists are reviewed from the viewpoint of the material design for the suppression of stochastic effects.