High-brightness LDP source for EUVL mask inspection

The Laser-assisted discharge-produced (LDP) plasma EUV source was developed as a light source for actinic mask inspection and beamline application. Since the focused laser irradiation is used to ignite the discharge, the LDP plasma has a unique feature of high brightness and high power. It can be operated at the frequency of up to 10 kHz generating <200 W/mm2/sr in-band EUV brightness at plasma. The source reliability is also proven in the field as a source for actinic mask inspection. In the paper, the key performances of the LDP source will be discussed.