A new method to prepare minimum-mass tin EUV targets

Minimum-mass target is an effective way to control debris produced during 13.5 nm EUV emission. In this work, we introduce a new method to fabricate 500 ?m PVA air bubbles which is the supporting medium for tin layer using our home-made apparatus. We found that the thinner needle could produce smaller PVA bubbles at a stirring speed of > 420 rpm and the air bubbles were found to be stable more than 40 min which satisfies the requirement of EUV target. Tin elements were assembled on the PVA air bubbles and the presence of tin was confirmed by ICP experiment. The stability of the PVA air bubbles shows that they could be used as EUV emission target in the future.