Patent ID: 11894214
Assignee: KLA CORPORATION
Field: Measurement (Instruments)
Classification: CPC H  G | IPC G  H

Claim 9:
10. A system, comprising:
an electron beam tool including:
an electron beam emitter configured to emit electrons in an electron beam towards a specimen;
a stage configured to hold the specimen;
an electron detector configured to detect secondary and/or backscattered electrons emitted by the specimen to obtain electron data, wherein the electron data defines a detection signal; and

a controller in electronic communication with the electron beam tool, the controller having a processor;
wherein the controller is configured to:
instruct the electron beam emitter to modulate the electron beam to obtain a beam signal wherein the modulating is based on a wave that controls the beam signal, and wherein the modulating includes adjusting a beam current that reaches the specimen;
determine a comparison between the wave controlling the beam signal and a wave for the detection signal; and
filter the detection signal using the comparison.