Enhanced extreme ultraviolet lighting using carbon nanotube-based cold cathode electron beam irradiation

Laser-produced tin (Sn) plasma (LPP) is used to produce high-performance semiconductors using extreme ultraviolet (EUV), but LPP generates debris that limits the lifespan of the optical system, so research on debris mitigation is being conducted. When electrons are directly irradiated to a solid target, occurrence of debris can be minimized, and compact and low-cost EUV lighting can be manufactured. Here, we demonstrated enhanced EUV generation by optimizing the irradiation of Sn with electrons emitted from carbon nanotube-based cold cathode electron beam (C-beam). To minimize debris, a usable zone in which Sn does not melt was identified. It was demonstrated that using two C-beams in the usable zone increased the EUV intensity by about two times compared to using one C-beam. The multiple C-beam irradiation technique enables high-output EUV lighting by overlapping EUV light, which should be led by the development of advanced lithography and inspection technology.