Pattern cross-sectional shape estimation system and program

Patent metadata

Field	Value
Publication number	US-11211226-B2
Application number	US-202016810969-A
Country	US
Kind code	B2
Filing date	Mar 6, 2020
Priority date	Apr 8, 2019
Publication date	Dec 28, 2021
Grant date	Dec 28, 2021

Abstract

The present disclosure provides a pattern cross-sectional shape estimation system which includes a charged particle ray device which includes a scanning deflector that scans a charged particle beam, a detector that detects charged particles, and an angle discriminator that is disposed in a front stage of the detector and discriminates charged particles to be detected, and an arithmetic device that generates a luminance of an image, and calculates a signal waveform of a designated region on the image using the luminance. The arithmetic device generates angle discrimination images using signal electrons at different detection angles, and estimates a side wall shape of a measurement target pattern.

First claim

What is claimed is:

1. A pattern cross-sectional shape estimation system, comprising:
a charged particle ray device which includes a scanning deflector that scans a charged particle beam emitted from a charged particle source, a signal electron focusing lens and a signal electronic aperture that are controlled to perform discrimination of signal electrons emitted from a sample based on their angle, where the signal electron focusing lens controls a spread of signal electrons and the signal electronic aperture that restricts a detection angle of the signal electrons, and at least one detector that detects the signal electrons at different detection angles; and
an arithmetic device that generates a luminance of an image based on an output of the at least one detector, and calculates a signal waveform of a designated region on the image using the luminance,
wherein the arithmetic device generates a plurality of angle discrimination images using signal electrons at the different detection angles, and estimates a side wall shape of a measurement target pattern based on a change in a pattern dimension calculated from a signal waveform of each angle discrimination image with respect to each of the different detection angles.

2. The pattern cross-sectional shape estimation system according to claim 1 ,
wherein the arithmetic device estimates a cross-sectional shape in a depth direction of the measurement target pattern from a change in a dimensional value obtained with a different threshold value for a signal waveform of each of the angle discrimination images.

3. The pattern cross-sectional shape estimation system according to claim 1 ,
wherein the arithmetic device classifies a pattern shape based on an estimation result of the measurement target pattern, and displays information on the pattern shape and information on a taper angle of a taper portion included in the measurement target pattern on a display screen.

4. The pattern cross-sectional shape estimation system according to claim 1 ,
wherein the arithmetic device acquires, as a reference, a change in dimension with respect to a detection angle of a known pattern whose cross-sectional shape is known in advance from a storage device, and estimates a shape of the measurement target pattern from a difference between a change of the known pattern and a change in the calculated pattern dimension with respect to a detection angle.

5. A non-transitory computer readable storage medium storing thereon a program for causing a computer to execute a process of estimating a cross-sectional shape of a pattern to be measured,
wherein the process comprises the steps of:
performing discrimination of signal electrons emitted from a sample, scanned by a charged particle beam emitted from a charged particle source, based on their angle, by controlling an electron focusing lens and a signal electronic aperture, where the signal electron focusing lens controls a spread of signal electrons and the signal electronic aperture restricts a detection angle of the signal electrons;
detecting, by at least one detector, the signal electrons at different detection angles;
generating, by an arithmetic device, a luminance of an image based on an output of the at least one detector;
calculating, by the arithmetic device, a signal waveform of a designated region on the image using the luminance,
generating, by the arithmetic device, a plurality of angle discrimination images using signal electrons at the different detection angles; and
estimating, by the arithmetic device, a side wall shape of a measurement target pattern based on a change in a pattern dimension calculated from a signal waveform of each angle discrimination image with respect to each of the different detection angles.

Assignees

• Hitachi High Tech Corp

Inventors

• Yokosuka Toshiyuki
• Kitsuki Hirohiko
• Bizen Daisuke
• Suzuki Makoto
• Abe Yusuke
• Yasui Kenji
• Osaki Mayuka
• Kazumi Hideyuki

Classifications

• H01J37/244 Primary

  Detectors; Associated components or circuits therefor · CPC title

• H01J2237/24578

  Spatial variables, e.g. position, distance · CPC title

• H01J2237/2817

  Pattern inspection · CPC title

• H01J37/222

  Image processing arrangements associated with the tube · CPC title

• H01J37/28 Primary

  with scanning beams {(H01J37/268, H01J37/292, H01J37/2955 take precedence)} · CPC title