ECLIPSE-CHIPS: Plasma-Produced Materials to Investigate Laser-Produced Plasmas for Microelectronics Manufacturing

About This Grant

This award is made in response to Dear Colleague Letter 24-130, as part of the ECosystem for Leading Innovation in Plasma Science and Engineering (ECLIPSE) interdisciplinary program. This grant supports the research looking to advance photolithography, a technology that is critical for the large-scale manufacturing of microelectronics. Photolithography is used to define the exceedingly small integrated circuits that enable the large computing power of devices such as smartphones and laptop computers. Continuous improvements in computing power require smaller and smaller circuit features, which in turn require performing photolithography with shorter and shorter wavelengths of light. State-of-the-art photolithographic tools can now utilize extreme ultraviolet (EUV) radiation, but they require incredibly complex and expensive equipment. It is the goal of this project to explore a new approach to EUV generation that overcomes current limitations in terms of emission wavelength and intensity. This new approach utilizes a plasma, which is a partially ionized gas, to produce aerosols of small particles composed of metals such as tin. An intense laser pulse fully ionizes the tin aerosol and generates bright EUV radiation. By tuning the properties of the plasma, it is possible to control the properties of the tin nanoparticles and, in turn, improve the performance of the EUV source in terms of emission wavelength and energy efficiency. This is critical to achieve ever-brighter EUV sources and maximize semiconductor manufacturing rates. This highly multidisciplinary research involves physics, chemistry, materials science and advanced manufacturing. The project seeks to contribute to the development of a highly skilled workforce in the critical area of semiconductor manufacturing. The research outcomes look to benefit the US economy and society by keeping it at the forefront of scientific and technological innovation in a highly competitive field. In recent years, tin droplets coupled with pulsed lasers have emerged as viable sources of EUV generation for photolithography. In these systems, a laser pulse evaporates the tin droplet and ionizes its vapor to achieve EUV emission. Commercial devices use micron-sized tin droplets, leading to incomplete utilization of the material upon laser pulse exposure and to the formation of fragments that contaminate the collection optics. This project seeks to investigate the use of aerosols of metal nanoparticles as targets for EUV generation. By systematically varying the size and density of the tin nanoparticles, it is possible to explore new regimes of laser-matter coupling, with the ultimate goal of improving spectral purity and EUV emission intensity compared to current droplet-based sources. To achieve this, some scientific barriers need to be overcome, in particular with respect to understanding the nucleation, growth, and transport of tin nanoparticles in low-temperature plasma sources. The team utilizes a range of diagnostic techniques, such as optical emission and mass spectroscopy, to map the relation between plasma and aerosol properties, together with their effect on EUV emission. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.