Particle image velocimetry of extreme ultraviolet lithography systems
AssigneeTaiwan Semiconductor Manufacturing Company, Ltd.
InventorsEn Hao Lai, Chi Yang, Shang-Chieh Chien, Li-Jui Chen, Po-Chung Cheng
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Abstract
A method includes irradiating a target droplet in an extreme ultraviolet (EUV) light source of an extreme ultraviolet lithography tool with non-ionizing light from a droplet illumination module. The method further includes detecting light reflected and/or scattered by the target droplet, and performing particle image velocimetry, based on the detected light, to determine a velocity of the target droplet. The method also includes adjusting a time delay between a generation of the target droplet and a generation of an excitation laser beam based on the velocity of the target droplet.
Claims20
A method, comprising:
- irradiating a target droplet in an extreme ultraviolet (EUV) light source of an extreme ultraviolet lithography tool with non-ionizing light from a droplet illumination module;
- detecting light reflected and/or scattered by the target droplet;
- performing particle image velocimetry, based on the detected light, to determine a velocity of the target droplet;
- and
- adjusting a time delay between a generation of the target droplet and a generation of an excitation laser beam based on the velocity of the target droplet.
A method, comprising:
- irradiating one or more of tin droplets and tin debris in an extreme ultraviolet light source of an extreme ultraviolet lithography tool with non-ionizing light from a droplet illumination module;
- detecting light reflected and/or scattered by the one or more of the tin droplets and the tin debris;
- and
- performing particle image velocimetry, based on the detected light, to determine a velocity of the one or more of the tin droplets.
An apparatus for monitoring flow parameters of particles in an extreme ultraviolet light source of an extreme ultraviolet lithography system, comprising:
- a droplet illumination module comprising a radiation source configured to illuminate a target droplet;
- a droplet detection module configured to detect light reflected and/or scattered by the target droplet;
- and
- a controller coupled to the droplet illumination module and the droplet detection module and configured to:
- perform particle image velocimetry to determine a velocity of the target droplet, and
- adjust a time delay between a generation of the target droplet and a generation of an excitation laser beam pulse based on the velocity of the target droplet.
Dependencies are inferred from the claim text.