Development of Tin Droplet Target for 13.5 nm Lithography

Abstract

A new flow control method for a tin droplet generator in a vacuum has been developed for Extreme Ultra-Violet Lithography. A vibration rod forced by a piezoelectric crystal varies the flow resistance, thus changing the flow rate at a high repetition rate. This droplet generator is advantageous for high temperature liquids such as molten metal. The formation of tin droplets using this generator was demonstrated at a frequency range of 10 kHz to 22 kHz by a 100 m nozzle.