US 11,940,738 B2
Droplet splash control for extreme ultra violet photolithography
Po-Ming Shih, Hsinchu (TW); and Chi-Hung Liao, Hsinchu (TW)
Assigned to Taiwan Semiconductor Manufacturing Co., Ltd., Hsinchu (TW)
Filed by Taiwan Semiconductor Manufacturing Co., Ltd., Hsinchu (TW)
Filed on Jun. 15, 2020, as Appl. No. 16/902,085.
Prior Publication US 2021/0389675 A1, Dec. 16, 2021
Int. Cl. G03F 7/00 (2006.01)
CPC G03F 7/705 (2013.01) [G03F 7/70033 (2013.01); G03F 7/70191 (2013.01)] 20 Claims
OG exemplary drawing
 
1. A photolithography system, comprising:
a droplet generator configured to output a stream of droplets;
a droplet receiver positioned to receive and collect the droplets;
a laser configured to irradiate the droplets at an irradiation location between the droplet generator and the droplet receiver;
a collector configured to receive extreme ultraviolet radiation from the droplets and to reflect the extreme ultraviolet radiation for use in photolithography;
a charge electrode positioned between the irradiation location and the droplet receiver;
a counter electrode positioned within the droplet receiver downstream from the charge electrode with respect to a direction of travel of the droplets;
a droplet sensor positioned within the droplet receiver and configured to generate sensor signals indicative of a speed of the droplets within the droplet sensor; and
a control system configured to receive the sensor signals, to apply a first voltage to the charge electrode, and to apply a second voltage to the counter electrode, the first voltage being selected to impart a net electric charge to the droplets as the droplets pass adjacent to the charge electrode, the second voltage being selected to reduce a speed of the droplets within the droplet receiver, wherein the control system is configured to adjust one or both of the first and second voltages responsive to the sensor signals.