Target supply control apparatus and method in an extreme ultraviolet light source

A method of controlling target material traveling along a trajectory toward a target space in a chamber of an extreme ultraviolet (EUV) light source, the method comprising:

• emitting target material through a longitudinal opening defined in a nozzle, the opening being fluidly coupled to a reservoir configured to contain the target material, wherein the target material produces EUV light when in a plasma state;
• detecting an aspect relating to the target material as the target material travels along the trajectory toward the target space;
• producing a one-dimensional signal from the detected aspect;
• analyzing the one-dimensional signal;
• and
• modifying one or more characteristics of the emitted target material based on the analysis of the one-dimensional signal.

A method of tuning a target apparatus for an extreme ultraviolet (EUV) light source, the method comprising:

• operating the target apparatus including a nozzle in fluid communication with a reservoir in tuning mode, the tuning mode operating comprising:
• releasing target material from the nozzle along a trajectory toward the target space, wherein the target material produces EUV light when in a plasma state;
• adjusting a state of the target material that is released from the nozzle including adjusting one or more characteristics of the target material including adjusting one or more of a location and a time at which target material coalesces into targets along the trajectory prior to entering the target space;
• detecting one or more aspects related to the target material as the target material travels along the trajectory toward the target space, wherein detecting comprises detecting at a plurality of different adjustment states;
• and
• based on the detected one or more aspects, determining a set of steady-state performance characteristics associated with the target material;
• after determining the set of steady-state performance characteristics associated with the target material, then operating the target apparatus in steady-state mode based on the set of steady-state performance characteristics;
• and
• notifying a control apparatus of the EUV light source that the target apparatus is operating in steady-state mode.