In this work we present the status of our high repetition-rate/high power EUV source facility. The masslimited
target concept has demonstrated high conversion efficiencies (CE) previously, with precision solid
state lasers. Currently, experiments are in progress with high power high repetition-rate (3-4 kHz) Qswitched
laser modules. We present a new dedicated facility for the high power EUV source. Also, we
present a precision EUV energy-meter, which is developed for absolute EUV energy measurements.
Spectral measurements of the tin-doped droplet laser plasma are performed with a flat-field spectrometer
(FFS) with a back-illuminated CCD camera. We address the issue of maintaining the calibration of the
EUV optics during source operation at non-optimum intensity at high repetition-rate, which is required for
CE improvement studies. Here we present the unique metrology for measuring EUV energies under a
variety of irradiation conditions without degrading EUV optics, even at high repetition rates (multi-kHz).
Tin-doped droplet target has been integrated with several lasers including high power high repetition rate lasers
and demonstrated high conversion efficiencies for all the lasers. This implies the EUV source power is linearly
increasing as the laser frequency goes higher. The target exhibit very low out-of-band radiation and debris emission.
The drawback of increasing the repetition rate of the target and the laser will be limited. The total amount
of tin consumed for a EUVL source system is also small enough to be operated for a long term without large effort
for recycling of the target materials. We address and demonstrate in this paper the primary issues associated
with long-term high power EUV sources for high volume manufacturing (HVM) using tin-doped droplet target.
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