Xe-filled capillary Z-pinch discharge light source for extreme-ultraviolet (EUV) lithography

摘要

A high repetitive, compact and low-debris Xe-filled capillary Z-pinch discharge system for EUVL has been designed and fabricated as an alternative to laser-produced plasmas as EUV sources. The features of our device are as follows (1) to decrease the current density on the surfaces, the electrode structure has been made with large surface area, (2) to get enough EUV light flux, the anode structure has been devised to have large collection angle, (3) to enable the high repetition rate operation, the electrodes and the capillary can be cooled with forced water circulation. And static induction thyristors are used as switching elements, which enable the high repetition rate operation of the pulse power source (4). A magnetic switch has been set near the discharge part to provide preionization. We present investigations of the EUV emission from Xe-filled capillary Z-pinch discharge. In order to find optimum discharge conditions, the emission of xenon excited in a capillary discharge in this region has been examined as a function of peak discharge current, gas pressure and inner diameter of capillary. The performance of the EUV radiation from the capillary has been studied by the photodiode signal and pinhole images of the capillary discharge taken to characterize the plasma dynamics. Also the spectroscopic measurements in the EUV region will be conducted. This source could be suitable for EUV lithography.