Apparatus for generating extreme ultraviolet radiation

An apparatus for generating extreme ultraviolet (EUV) radiation comprises a droplet generator, an excitation laser source, an energy detector, and a feedback controller. The droplet generator is configured to generate target droplets. The excitation laser is configured to generate a pre-pulse and a main pulse to convert the target droplets to plasma by heating. The energy detector is configured tomeasure a variation in EUV energy generated when the target droplets are converted to plasma. The feedback controller is configured to adjust a time delay between a subsequent pre-pulse and main pulse generated by the excitation laser based on the variation in EUV energy generated by a given main pulse. 一种产生极紫外(EXTREME ULTRAVIOLET；EUV)辐射的装置，其包含液滴产生器、激发激光源、能量检测器以及回授控制器。液滴产生器是配置以产生目标液滴。激发激光源是配置以产生预脉冲和主脉冲，以通过加热来将目标液滴转换为电浆。能量检测器是配置以量测当目标液滴被转换为电浆时所产生的极紫外能量的偏差。回授控制器是配置以基于极紫外能量的偏差来调整透过激发激光源所产生的后续预脉冲和主脉冲间的时间延迟，极紫外能量的偏差是透过给定主脉冲来产生。