Numerical investigation of thulium laser for laser-produced tin plasma EUV light source
Chun-Tse Wu1*, Yao-Li Liu1, Po-Yen Lai1, Shih-Hung Chen1
1Physics, National Central University, Taoyuan, Taiwan
* Presenter:Chun-Tse Wu, email:109222032@cc.ncu.edu.tw
Development of the laser-produced plasma extreme ultraviolet (LPP-EUV) light source is critical for success of high-volume manufacturing (HVM) in semiconductor industries. The power scalability, spatial coherence, and conversion efficiency (CE) are three major figures of merit of LPP-EUV light sources. Therefore, a one-dimensional simulation framework was developed to investigate the CE of LPP-EUV light source.
Since the processes of LPP-EUV light emission across multiple time scales, the simulation models of the simulation framework include the collisional-radiative model (for obtaining the charge states), the hybrid atomic model (for obtaining the energy level population of different charge states), atomic physics model (for obtaining atomic properties), and MHD simulation model (for obtaining plasma evolution), and radiation transport model (for obtaining the CE of EUV light). The simulation framework has been benchmarked using an experimental result and shows reliable qualitative results [1].
The CE of LPP-EUV light source can be affected by varying laser wavelengths due to the change of laser absorption rate and the plasma expansion processes. The thulium laser is recently considered as a promising pump laser source for LPP-EUV light sources due to its high efficiency in converting electrical power to laser light, such that enhance the cost-performance ratio for HVM [2]. Therefore, we are motivated to investigate the CE of LPP EUV light sources based on the thulium laser, which is compared with the sources based on Nd:YAG laser and carbon dioxide laser.

[1] Po-Yen Lai. "Numerical study of laser-driven plasma spectroscopy and kinetic behavior of a collisional plasma: For application of a laser-produced Sn plasma extreme ultraviolet light source." Ph.D. Thesis. National Central University, 2016.
[2] Behnke, L., Schupp, R., Bouza, Z., Bayraktar, M., Mazzotta, Z., Meijer, R., ... & Versolato, O. O. " Extreme ultraviolet light from a tin plasma driven by a 2-µm-wavelength laser." Optics express, 2021.


Keywords: Laser-Produced Plasma, Extreme Ultraviolet, Fluid Simulation