Study on 100 kHz Repetitive Frequency Tin Droplet Targets

Tin droplet generator is a crucial submodules of the light source used in laser-pulsed plasma extreme ultraviolet lithography. Such a light source requires a tin droplet target with high repetition rate, small diameter, and good stability. This study presents our recent progress on the droplet generator, encompassing the droplet diameter, repetition rate, spacing between adjacent droplets, and position stability. The generated tin droplets exhibit a diameter of similar to 40 mu m, spacing of 230 mu m between the adjacent droplets, and stable operating time of 5 h at a repetition rate of 100 kHz. Within a 10 s interval, the calculated standard deviation of the droplet positions in the vertical and horizontal directions are approximately 2 mu m and 1 mu m, respectively. However, the aspects of droplet usability, such as the droplet diameter, operating time, and long- term position stability require further improvement.