EUV photomask inspection apparatus

An EUV photomask inspection apparatus comprising:

• a light source configured to emit a first light having a wavelength in a visible light range;
• a beam splitter configured to transmit or reflect the first light;
• an objective lens configured to allow the first light to pass through at least a portion of a mask structure which includes an EUV photomask and a pellicle on the EUV photomask, the objective lens configured to form a first focus in the mask structure;
• a light detector configured to detect first reflected light, the first reflected light corresponding to the first light being reflected from the mask structure;
• a pinhole plate in front of at least one of the light source and the light detector, and configured to remove a portion of at least one of the first light and the first reflected light;
• a rotation mirror configured to change a path of the first light from the beam splitter;
• and
• relay lenses configured to adjust a size of the first light being incident from the rotation mirror and transmitting the first light to the objective lens,
• wherein the light detector includes a detection module and a thermoelectric cooling module configured to reduce thermal noise of the detection module,
• the first focus is a confocal point that is in a conjugate relationship with a focus in the pinhole plate and a focus in the light detector.

An EUV photomask inspection apparatus comprising:

• a plurality of optical systems, each optical system of the plurality of optical systems respectively configured to simultaneously form a plurality of different confocal points on an inspection object,
• wherein a first optical system among the plurality of optical systems includes,
• a light source configured to emit first light,
• a beam splitter configured to transmit or reflect the first light,
• an objective lens configured to allow the first light to pass through at least a portion of the inspection object to form a first focus on the inspection object,
• a light detector configured to detect first reflected light corresponding to the first light reflected from the inspection object, and including a photo multiplier tube (PMT) and an avalanche photodiode (APD),
• condensing lenses between the light source and the beam splitter;
• and
• a pinhole plate between the condensing lenses and removing a portion of the first light.