公开(公告)号：US20180348397A1

公开(公告)日：2018-12-06

申请号：US16058000

申请日：2018-08-08

Applicant: Gigaphoton Inc.

Inventor： Hideyuki HAYASHI ,  Takeshi OKAMOTO

IPC: G01V8/10

CPC classification number: H05G2/00

Abstract: A droplet timing sensor that detects droplet passage timing by receiving a light from a light source unit with which a droplet is irradiated in an extreme ultraviolet light generating apparatus eliminates an influence of droplet passage on light source control for obtaining a constant light income. The droplet timing sensor includes: a light source unit configured to irradiate a droplet with an illumination light at a predetermined position; a light receiving unit (70) configured to receive the illumination light having passed through the predetermined position and detect a change in a light income; and a light source controller (301) configured to obtain a frequency distribution of light incomes measured multiple times with time using a statistical processing unit (76), and control an output of the light source unit based on a light income at maximum frequency.