Abstract: A method of determining aberrations in images obtained by a charged-particle beam tool, comprising: a) obtaining two or more images of a sample, wherein each image is obtained at a known relative difference in a measurement condition of the charged-particle beam tool; b) selecting an estimated aberration parameter for the aberrations of a probe profile representing the charged-particle beam used by the charged-particle beam tool; c) evaluating an error function indicative of the difference between the two or more images and two or more estimated images that are a function of the estimated aberration parameter and the known relative difference in the measurement condition; d) updating the estimated aberration parameter; e) performing processes c) and d) iteratively; f) determining the final aberration parameter as the estimated aberration parameter that provides the smallest value of the error function.

Abstract: A method of determining aberrations in images obtained by a charged-particle beam tool, comprising: a) obtaining two or more images of a sample, wherein each image is obtained at a known relative difference in a measurement condition of the charged-particle beam tool; b) selecting an estimated aberration parameter for the aberrations of a probe profile representing the charged-particle beam used by the charged-particle beam tool; c) evaluating an error function indicative of the difference between the two or more images and two or more estimated images that are a function of the estimated aberration parameter and the known relative difference in the measurement condition; d) updating the estimated aberration parameter; e) performing processes c) and d) iteratively; f) determining the final aberration parameter as the estimated aberration parameter that provides the smallest value of the error function.