Patent Number: 
Section: claims

1. An apparatus for measuring and controlling a target trajectory within a chamber apparatus for generating extreme ultraviolet light from plasma generated by irradiating a droplet target supplied from a target injection nozzle with a driver laser beam from an external driver laser, said apparatus comprising:a nozzle adjustment mechanism for adjusting a position and particular angles of said target injection nozzle, wherein said nozzle adjustment mechanism is configured to adjust a first angle of said target injection nozzle around a first rotational axis and to adjust a second angle of said target injection nozzle around a second rotational axis orthogonal to the first rotational axis;a target trajectory measuring unit for measuring a target trajectory formed by a droplet target supplied from said target injection nozzle to obtain trajectory information on the target trajectory;a target trajectory angle detecting unit for obtaining an angle deviation between the target trajectory represented by the trajectory information obtained by said target trajectory measuring unit and a predetermined target trajectory; anda nozzle adjustment controller for controlling said nozzle adjustment mechanism based on the angle deviation obtained by said target trajectory angle detecting unit such that the droplet target supplied from said target injection nozzle passes through a predetermined position. 2. The apparatus according to claim 1, further comprising:a displacement gauge for measuring position displacement of said target injection nozzle;wherein said nozzle adjustment controller controls said nozzle adjustment mechanism based on an output signal of said displacement gauge such that the position of said target injection nozzle coincides with a reference position. 3. The apparatus according to claim 1, wherein:said target trajectory measuring unit measures a position of a center of a tip end of said target injection nozzle and the target trajectory to obtain the trajectory information on the target trajectory; andsaid target trajectory angle detecting unit obtains the angle deviation between the target trajectory represented by the trajectory information obtained by said target trajectory measuring unit and the predetermined target trajectory with the measured position of the center of the tip end of said target injection nozzle as a reference point. 4. The apparatus according to claim 1, wherein:said nozzle adjustment mechanism includes a nozzle position adjustment mechanism for adjusting the position of said target injection nozzle, and a nozzle angle adjustment mechanism for adjusting the particular angles of said target injection nozzle; andsaid nozzle adjustment controller controls said nozzle position adjustment mechanism and said nozzle angle adjustment mechanism to eliminate the angle deviation obtained by said target trajectory angle detecting unit. 5. The apparatus according to claim 1, wherein:said nozzle adjustment mechanism includes a nozzle position adjustment mechanism for adjusting the position of said target injection nozzle, and a nozzle angle adjustment mechanism for adjusting the particular angles of said target injection nozzle; andsaid nozzle adjustment controller controls said nozzle position adjustment mechanism such that the position of said target injection nozzle coincides with a reference position, and controls said nozzle angle adjustment mechanism to eliminate the angle deviation obtained by said target trajectory angle detecting unit. 6. The apparatus according to claim 1, further comprising:a detector laser for irradiating the droplet target supplied from said target injection nozzle with a detector laser beam;a light receiving element for detecting one of the detector laser beam passing between the droplet targets and the detector laser beam reflected by the droplet target; anda trigger timing adjusting unit for sensing timing when the droplet target passes through the predetermined position based on a detection signal supplied from said light receiving element, and sending out a trigger signal for adjusting trigger timing of said driver laser to said driver laser. 7. The apparatus according to claim 1, wherein said target trajectory measuring unit includes at least two imaging devices, and obtains images of the droplet target at least in two directions to obtain the trajectory information on the target trajectory. 8. The apparatus according to claim 7, wherein said two imaging devices obtain images of the droplet target in two directions orthogonal to each other. 9. The apparatus according to claim 8, whereinsaid two imaging devices obtain images of the droplet target in two directions in parallel to said first and second rotational axes, respectively. 10. The apparatus according to claim 1, wherein said target trajectory measuring unit includes a one-dimensional line sensor. 11. The apparatus according to claim 10, wherein said target trajectory measuring unit includes at least two one-dimensional line sensors, and measures the position of the target trajectory at least in two locations along the target trajectory. 12. The apparatus according to claim 1, wherein said target trajectory measuring unit includes a position sensitive detector. 13. The apparatus according to claim 12, wherein said target trajectory measuring unit includes at least two position sensitive detectors, and measures the position of the target trajectory at least in two locations along the target trajectory. 14. The apparatus according to claim 7, wherein said target trajectory measuring unit includes an imaging light source for illuminating an object of imaging. 15. A method of measuring and controlling a target trajectory within a chamber apparatus for generating extreme ultraviolet light from plasma generated by irradiating a droplet target supplied from a target injection nozzle with a driver laser beam from an external driver laser, said method comprising the steps of:(a) measuring a target trajectory formed by a droplet target supplied from said target injection nozzle to obtain trajectory information on the target trajectory;(b) obtaining an angle deviation between the target trajectory represented by the trajectory information obtained at step (a) and a predetermined target trajectory; and(c) adjusting a position and particular angles of said target injection nozzle based on the angle deviation obtained at step (b) such that the droplet target supplied from said target injection nozzle passes through a predetermined position, wherein a first angle of said target injection nozzle is adjusted around a first rotational axis and a second angle of said target injection nozzle is adjusted around a second rotational axis orthogonal to the first rotational axis. 16. The apparatus according to claim 1, wherein said target trajectory measuring unit is provided in a second frame separate from a first frame provided with said chamber apparatus. 17. An apparatus for measuring and controlling a target trajectory within a chamber apparatus for generating extreme ultraviolet light from plasma generated by irradiating a droplet target supplied from a target injection nozzle with a driver laser beam from an external driver laser, said apparatus comprising:a nozzle adjustment mechanism for adjusting at least one of a position and an angle of said target injection nozzle wherein said nozzle adjustment mechanism is configured to adjust a first angle of said target injection nozzle around a first rotational axis and to adjust a second angle of said target injection nozzle around a second rotational axis orthogonal to the first rotational axis;a target trajectory measuring unit for measuring a target trajectory formed by a droplet target supplied from said target injection nozzle to obtain trajectory information on the target trajectory;an imaging device for obtaining images of a tip end of said target injection nozzle;a target trajectory angle detecting unit for obtaining an angle deviation between the target trajectory and the predetermined target trajectory based on the trajectory information obtained by said target trajectory measuring unit and the images obtained by said imaging device; anda nozzle adjustment controller for controlling said nozzle adjustment mechanism based on the angle deviation obtained by said target trajectory angle detecting unit such that the droplet target passes through a predetermined position.