Kla Corporation

Konstantin Tsigutkin

Larissa Juschkin

Debashis De Munshi

Methods and systems for determining one or more characteristics of light in an optical system are provided. One system includes first detector(s) configured to detect light having one or more wavelengths shorter than 190 nm emitted from a light source at one or more first angles mutually exclusive of one or more second angles at which the light is collected from the light source by an optical system for illumination of a specimen and to generate first output responsive to the light detected by the first detector(s). In addition, the system includes a control subsystem configured for determining one or more characteristics of the light at one or more planes in the optical system based on the first output.

Determining one or more characteristics of light in an optical system

An inspection system and a method of using the same are disclosed. The inspection system comprises an illumination source configured to emit an extreme ultraviolet (EUV) illumination beam for illuminating a sample, one or more first multi-cell detectors configured to generate a first illumination intensity distribution signal based on a first photocurrent, one or more second multi-cell detectors configured to generate a second illumination intensity distribution signal based on a second photocurrent, a detector assembly configured to receive the illumination beam and generate images, and a controller configured to: receive the images from the detector assembly, calibrate the second illumination intensity distribution signal to the images by mapping distortions in the second illumination intensity distribution signal to distorted pixels in the images, increase or decrease intensities of the distorted pixels in the images to generate corrected images, and detect defects on the samples.

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Pleasanton, CA, United States of America

Konstantin Tsigutkin