Semiconductor processing tool and methods of operation

A method, comprising:

• determining, by a controller of an extreme ultraviolet (EUV) radiation source, that a detection circuit of a droplet generator (DG) head included in the EUV radiation source is in an open-circuit configuration during an exposure operation performed by a lithography system in which the EUV radiation source is included;
• determining, by the controller, that the detection circuit has transitioned from the open-circuit configuration to a closed-circuit configuration during the exposure operation,
• wherein a blockage, at an aperture of the DG head through which droplets of a target material are provided into a vessel of the EUV radiation source, closes the detection circuit across a first electrode element and a second electrode element of the detection circuit;
• and
• causing, by the controller, the exposure operation to be terminated based on determining that the detection circuit has transitioned from the open-circuit configuration to the closed-circuit configuration during the exposure operation.

An extreme ultraviolet (EUV) radiation source, comprising:

• a vessel;
• a droplet generator (DG) head including an aperture through which droplets of a target material are ejected into the vessel;
• and
• a detection circuit comprising:
• a plurality of electrode elements around a perimeter of the aperture;
• and
• a signal generator configured to generate a signal when a conductive path is formed between two or more of the plurality of electrode elements,
• wherein the signal is generated to indicate that a blockage of at least a portion of the aperture has occurred.