Micromachining of Silica Glass Using EUV Radiation of Laser-Produced Plasma

Abstract

We are investigating the micromachining of silica glass using extreme ultraviolet (EUV) light from laser-produced plasma (LPP). The present investigation deals with the ablation using EUV light of around 13.5 nm and 11 nm generated in laser-produced Sn plasma and Xe plasma, respectively. CO₂ laser and Nd:YAG lasers were used as pump lasers. The EUV radiation was focused on the surface of silica glass through the meshed mask using an ellipsoidal mirror coated with gold film. The results showed that the silica glass was successfully ablated by EUV light from the Nd:YAG-LPP. The maximum ablation rate was 42 nm per shot for 11-nm light, and 25 nm per shot for 13.5-nm light. On the other hand, EUV radiation from the CO₂-LPP did not ablate the silica glass. This is presumably caused by the lower EUV irradiation intensity due to the long pulse duration of the CO₂ laser.