Extreme ultraviolet light generation apparatus, droplet generation control method, and electronic device manufacturing method

A droplet generation control method with an extreme ultraviolet light generation apparatus configured to generate extreme ultraviolet light by irradiating a droplet with laser light, comprising:

• generating the droplet of a target substance by applying an electric signal to a piezoelectric element to apply vibration reflecting the electric signal to the target substance in a liquid state to be output from the nozzle;
• measuring a passage interval of the droplets output from the nozzle by a first sensor;
• measuring a parameter related to the droplet by a second sensor different from the first sensor;
• setting a prohibited band of a duty of the electric signal based on data in which the duty and the parameter at the duty are associated with each other;
• and
• setting the duty of the electric signal to be output to the piezoelectric element while avoiding the prohibited band.

An electronic device manufacturing method, comprising:

• generating extreme ultraviolet light using an extreme ultraviolet light generation apparatus;
• outputting the extreme ultraviolet light to an exposure apparatus;
• and
• exposing a photosensitive substrate to the extreme ultraviolet light in the exposure apparatus to manufacture an electronic device,
• the extreme ultraviolet light generation apparatus being configured to generate the extreme ultraviolet light by irradiating a droplet with laser light, and including:
• a tank configured to store a target substance in a liquid state;
• a nozzle configured to output the target substance stored in the tank;
• a piezoelectric element configured to apply vibration reflecting an electric signal to the target substance to be output from the nozzle to generate the droplet of the target substance;
• a first sensor configured to measure a passage interval of the droplets output from the nozzle;
• a second sensor configured to measure a parameter related to the droplet;
• and
• a processor configured to set a prohibited band of a duty of the electric signal based on data in which the duty and the parameter at the duty are associated with each other, and set the duty of the electric signal to be applied to the piezoelectric element while avoiding the prohibited band.

An electronic device manufacturing method, comprising:

• generating extreme ultraviolet light using an extreme ultraviolet light generation apparatus;
• inspecting a defect of a reticle by irradiating the reticle with the extreme ultraviolet light;
• selecting a reticle using a result of the inspection;
• and
• exposing and transferring a pattern formed on the selected reticle onto a photosensitive substrate,
• the extreme ultraviolet light generation apparatus being configured to generate the extreme ultraviolet light by irradiating a droplet with laser light, and including:
• a tank configured to store a target substance in a liquid state;
• a nozzle configured to output the target substance stored in the tank;
• a piezoelectric element configured to apply vibration reflecting an electric signal to the target substance to be output from the nozzle to generate the droplet of the target substance;
• a first sensor configured to measure a passage interval of the droplets output from the nozzle;
• a second sensor configured to measure a parameter related to the droplet;
• and
• a processor configured to set a prohibited band of a duty of the electric signal based on data in which the duty and the parameter at the duty are associated with each other, and set the duty of the electric signal to be applied to the piezoelectric element while avoiding the prohibited band.