US Patent No. 10,366,862


Patent No. 10,366,862
Issue Date July 30, 2019
Title Method And System For Noise Mitigation In A Multi-beam Scanning Electron Microscopy System
Inventorship Doug K. Masnaghetti, San Jose, CA (US)
Richard R. Simmons, Los Altos, CA (US)
Mark A. McCord, Los Gatos, CA (US)
Rainer Knippelmeyer, Groton, MA (US)
Assignee KLA-Tencor Corporaton, Milpitas, CA (US)

Claim of US Patent No. 10,366,862

1. A multi-beam scanning electron microscopy apparatus comprising:a multi-beam scanning electron microscopy sub-system comprising:
a multi-beam electron beam source configured to generate a plurality of electron beams;
a sample stage configured to secure a sample;
an electron-optical assembly including a set of electron-optical elements configured to direct at least a portion of the plurality of electron beams onto a portion of the sample; and
a detector assembly configured to detect a plurality of electron signal beams emanating from the surface of the sample to form a plurality of images, each image associated with an electron beam of the plurality of electron beams, wherein a first image contains a first instance of a pattern element obtained from a first location of the sample and at least an additional image contains an additional instance of the pattern element at an additional location of the sample; and
a controller including one or more processors configured to execute a set of program instructions stored in memory for causing the one or more processors to:
receive the plurality of images from the detector assembly;
compare two or more of the images to identify one or more common positional noise components present in the two or more images; and
remove the identified one or more common positional noise components from one or more images of the plurality of images by shifting the one or more images by an amount equal in distance and opposite in direction to the one or more common positional noise components.