US 12,614,693 B2 · Automatic electron beam calibration on periodic nanostructures

Abstract

Systems, methods, and media for calibrating a scanning electron microscope (SEM). The system includes a processor and a memory. The memory stores instructions that, when executed by the processor, configure the system to perform operations. An electron microscope image of a periodic structure is generated by the SEM. A Fourier transform of the electron microscope image is computed to generate a spectrum. Reciprocal lattice vectors are computed based on a known periodicity of the periodic structure. A pixel mask is generated based on the reciprocal lattice vectors and applied to filter the spectrum. A quality metric is generated based on an aggregate magnitude of the filtered spectrum and a magnitude of a zero-frequency component of the filtered spectrum. A pixel scaling parameter, focus parameter, and/or stigmation parameter of the SEM are determined based on the quality metric.

Claims20

Dependent claims

A system comprising:

at least one processor;
and a memory storing instructions that, when executed by the at least one processor, configure the system to perform operations comprising:
obtaining an electron microscope image of a periodic structure, the electron microscope image being generated by a scanning electron microscope (SEM);
computing a Fourier transform of the electron microscope image to generate a spectrum;
computing reciprocal lattice vectors based on a known periodicity of the periodic structure;
generating a pixel mask based on the reciprocal lattice vectors;
generating a filtered spectrum by applying the pixel mask to the spectrum;
computing a quality metric based on:
an aggregate magnitude of components of the filtered spectrum;
and a magnitude of a zero-frequency component of the filtered spectrum;
and determining one or more operating parameters of the SEM based on the quality metric, the one or more operating parameters comprising at least one of:
a pixel scaling parameter;
a focus para meter;
or a stigmation parameter.

11 more elements

A method, performed by at least one processor, comprising:

obtaining an electron microscope image of a periodic structure, the electron microscope image being generated by a scanning electron microscope (SEM);
computing a Fourier transform of the electron microscope image to generate a spectrum;
computing reciprocal lattice vectors based on a known periodicity of the periodic structure;
generating a pixel mask based on the reciprocal lattice vectors;
generating a filtered spectrum by applying the pixel mask to the spectrum;
computing a quality metric based on:
an aggregate magnitude of components of the filtered spectrum;
and a magnitude of a zero-frequency component of the filtered spectrum;
and determining one or more operating parameters of the SEM based on the quality metric, the one or more operating parameters comprising at least one of:
a pixel scaling parameter;
a focus parameter;
or a stigmation parameter.

9 more elements

Dependencies are inferred from the claim text.

Automatic electron beam calibration on periodic nanostructures

Life of this patent

Automatic electron beam calibration on periodic nanostructures

Life of this patent

Abstract

Claims20