Extreme ultraviolet light generation apparatus

An extreme ultraviolet light generation apparatus that irradiates a target with a pulse laser beam at a plasma generation region, the apparatus comprising:

• a chamber provided with a through-hole;
• a conducting optical system configured to conduct the pulse laser beam to the plasma generation region in the chamber via the through-hole;
• a target supply device configured to output the target toward the plasma generation region;
• and
• a target detection section, the target detection section including:
• a light source;
• a transfer optical system;
• a first line sensor configured to output a first optical intensity distribution, along a first line that intersects with a trajectory of the target, obtained when part of an image that has been formed by irradiating the target outputted from the target supply device with light outputted from the light source is formed on a light-receiving unit of the first line sensor transferred by the transfer optical system;
• a second line sensor configured to output a second optical intensity distribution, along a second line that intersects with a trajectory of the target, obtained when part of an image that has been formed by irradiating the target outputted from the target supply device with light outputted from the light source is formed on a light-receiving unit of the second line sensor transferred by the transfer optical system;
• and
• a processing unit, connected to the first and second line sensors, configured to receive the first and second optical intensity distributions, calculate a center of gravity position in the first optical intensity distribution and a center of gravity position in the second optical intensity distribution, and calculate an actual path of the target from the calculated positions.

An extreme ultraviolet light generation apparatus that irradiates a target with a pulse laser beam at a plasma generation region, the apparatus comprising:

• a chamber provided with a through-hole;
• a conducting optical system configured to conduct the pulse laser beam to the plasma generation region in the chamber via the through-hole;
• a target supply device configured to output the target toward the plasma generation region;
• and
• a target detection section, the target detection section including:
• a light source;
• a transfer optical system;
• an image sensor configured to output image data of an image that has been formed by irradiating the target outputted from the target supply device with light outputted from the light source and that has then been formed on a light-receiving unit of the image sensor transferred by the transfer optical system;
• and
• a processing unit, connected to the image sensor, configured to receive the outputted image data, obtain a first optical intensity distribution along a first line that intersects with a trajectory of the target and a second optical intensity distribution along a second line that intersects with the trajectory, calculate a center position of an area in the first optical intensity distribution whose optical intensity is greater than or equal to a first threshold and a center position of an area in the second optical intensity distribution whose optical intensity is greater than or equal to a second threshold, and calculate an actual path of the target from the calculated positions.

An extreme ultraviolet light generation apparatus that irradiates a target with a pulse laser beam at a plasma generation region, the apparatus comprising:

• a chamber provided with a through-hole;
• a conducting optical system configured to conduct the pulse laser beam to the plasma generation region in the chamber via the through-hole;
• a target supply device configured to output the target toward the plasma generation region;
• and
• a target detection section, the target detection section including:
• a light source;
• a transfer optical system;
• a first line sensor configured to output a first optical intensity distribution, along a first line that intersects with a trajectory of the target, obtained when part of an image that has been formed by irradiating the target outputted from the target supply device with light outputted from the light source is formed on a light-receiving unit of the first line sensor transferred by the transfer optical system;
• a second line sensor configured to output a second optical intensity distribution, along a second line that intersects with a trajectory of the target, obtained when part of an image that has been formed by irradiating the target outputted from the target supply device with light outputted from the light source is formed on a light-receiving unit of the second line sensor transferred by the transfer optical system;
• and
• a processing unit, connected to the first and second line sensors, configured to receive the first and second optical intensity distributions, calculate a center position of an area in the first optical intensity distribution whose optical intensity is greater than or equal to a first threshold and a center position of an area in the second optical intensity distribution whose optical intensity is greater than or equal to a second threshold, and calculate an actual path of the target from the calculated positions.