Liquid Metal Micro-Droplet Generator for Laser Produced Plasma Target Delivery used in an Extreme Ultra-Violet Source

摘要

The implementation of a Laser Produced Plasma Extreme Ultra-Violet (LPP EUV) source requires a high-power laserfocused onto a target. In order to minimize the required laser input power the target material must have a highconversion efficiency to 13.5 nanometer radiation. Ideally, a pulsed laser is used and the target should be delivered insmall uniform volumes to a point in space at high repetition rates. The small volumes minimize the amount of debris,the high repetition rates enable higher power systems and the free space delivery alleviates thermal issues and allowslarge collection angles. It has been demonstrated that lithium and tin have very high conversion efficiencies and systemsolutions exist to use these materials. In this paper we describe the requirements and performance of a liquid metalmicro-droplet target generator capable of dispensing both lithium and tin. Finally it is shown that the current generatorperformance is sufficient to support stable source operation.