Osaka University

Tatsuhiko Yamanaka

Hiroyuki Furukawa

Noriaki Miyanaga

Yasukazu Izawa

Yoshinori Shimada

Katsunobu Nishihara

Masakatsu Murakami

Takayoshi Norimatsu

Atsushi Sunahara

Hiroaki Nishimura

Keiji Nagai

Mitsuo Nakai

Yasuhiko Sentoku

Kazuo Tanaka

Kunioki Mima

Ryosuke Kodama

Yoneyoshi Kitagawa

Tomoharu Okuno

Takahiro Hibino

Ryouji Matsui

Vasilli Zhakhovski

Shigeaki Uchida

Keisuke Shigemori

Masahiro Nakatsuka

An object of the present invention is to provide an extreme ultraviolet light source target which can emits extreme ultraviolet light with high emission efficiency. A solid target made of heavy metal or heavy-metal compound and having a density 0.5 to 80% that of the crystal density is used. When the target is irradiated with a laser beam, plasma of the heavy metal contained in the target is generated, and extreme ultraviolet light having a predetermined wavelength which corresponds to the kind of the heavy metal is emitted from the plasma. When the density of the target is made to be smaller than the crystal density as described above, space distribution of the density of the generated plasma can be controlled, and the region in which plasma absorbs energy of the laser beam overlaps the region in which the plasma emits the extreme ultraviolet light. Thus, emission efficiency can be improved, preventing energy loss. For example, in a case where the SnOtarget having a density 24% of the crystal density is used, the emission efficiency at around 13.5 nm wavelength is higher than in the case where a Sn crystal target is used.

Extreme ultraviolet light source and extreme ultraviolet light source target

A hollow tube having a pair of openings which have their respective different diameters and are opposed each other is prepared. Then, a pulsed laser beam is introduced into the hollow tube from the larger opening thereof and then, reflected multiply on the inner wall surface of the hollow tube. The introduced pulsed laser beam is focused during the traveling for the smaller opening of the hollow tube to generate a focused laser beam. The thus obtained focused laser beam is output from the smaller opening of the hollow tube.

Laser beam focusing apparatus and method for focusing a laser beam

Growing community of inventors

Suita, Japan

Tatsuhiko Yamanaka