Method and apparatus for determining a radiation beam intensity profile

An apparatus for determining an intensity profile of a radiation beam, the apparatus comprising:

• a diffraction structure moveable relative to a radiation beam from a first position, in which the diffraction structure is not irradiated by the radiation beam, to a second position, in which the diffraction structure is irradiated by the radiation beam, or from the second position to the first position;
• a radiation detector configured to detect diffracted radiation signals of the radiation beam diffracted by the diffraction structure;
• and
• a processor configured to execute instructions comprising:
• receiving data representing the diffracted radiation signals from the radiation detector;
• and
• determining an intensity profile, based on the received data representing the diffracted radiation signals.

A lithographic cell comprising:

• a radiation source configured to output a radiation beam;
• an apparatus that determines an intensity profile of the radiation beam, wherein the apparatus comprises:
• a diffraction structure moveable relative to the radiation beam from a first position, in which the diffraction structure is not irradiated by the radiation beam, to a second position, in which the diffraction structure is irradiated by the radiation beam, or from the second position to the first position;
• a radiation detector configured to detect diffracted radiation signals of the radiation beam diffracted by the diffraction structure;
• and
• a processor configured to execute instructions comprising:
• receiving data representing the diffracted radiation signals from the radiation detector;
• and
• determining an intensity profile, based on the received data representing the diffracted radiation signals.