UC San Diego

Extreme ultraviolet (EUV) lithography, the etching of fine semiconductor features with EUV light, is based on efficiently generating light of a wavelength within a narrow bandwidth around 13.5 nm by irradiating tin droplets with a laser. Simulating this process is beneficial to aid the target design and optimize the laser-plasma interaction for an enhanced EUV light output. In this work, we benchmarked the combination of the open source FLASH code and the commercially available SPECT3D against existing experimental data, showing that by stepping down the intensity by approximately a factor of two and shifting the spectra to the right by +0.55nm, the simulations provide results with a reasonable level of accuracy. Using the benchmarked settings to investigate four novel temporal pulse shapes, we found that the “step down”, “ step up” and “Gaussian ramp” pulses resulted in 1.4%, 4.0%, and 4.0% improvements in conversion efficiency respectively over their energy-equivalent square pulses. With improvements to the atomic level modeling, further benchmarking of the simulations, and the development of a robust open-source community around these two tools, we expect FLASH and SPECT3D to be the tools of choice for new researchers in EUV lithography.