Scanning electron microscope

Patent metadata

Field	Value
Publication number	US-9472376-B2
Application number	US-201314379715-A
Country	US
Kind code	B2
Filing date	Feb 18, 2013
Priority date	Mar 28, 2012
Publication date	Oct 18, 2016
Grant date	Oct 18, 2016

Abstract

An object of the invention is to provide a scanning electron microscope which forms an electric field to lift up, highly efficiently, electrons discharged from a hole bottom or the like even if a sample surface is an electrically conductive material. To achieve the above object, according to the invention, a scanning electron microscope including a deflector which deflects a scanning position of an electron beam, and a sample stage for loading a sample thereon, is proposed. The scanning electron microscope includes a control device which controls the deflector or the sample stage in such a way that before scanning a beam on a measurement target pattern, a lower layer pattern situated in a lower layer of the measurement target pattern undergoes beam irradiation on another pattern situated in the lower layer.

First claim

The invention claimed is:

1. A scanning electron microscope including an electron source, an objective lens which focuses an electron beam emitted from the electron source, a deflector which deflects a scanning position of the electron beam, a detector which detects electrons obtained by scanning a sample with the electron beam, and a sample stage for loading the sample thereon, the scanning electron microscope further including a control device, wherein
the control device is configured to control at least one of the deflector and the sample stage so as to position an irradiating position of the electron beam on a common floating electrode which is surrounded by an insulator and disposed in a bottom of both a measurement target pattern and a hole pattern or a groove pattern so as to irradiate the common floating electrode in the hole pattern or the groove pattern with the electron beam, and
the control device is configured to control at least one of the deflector and the sample stage so as to position the irradiating position of the electron beam on the measurement target pattern for detecting the electrons obtained by scanning an area including the measurement target pattern which is disposed at a different position from the hole pattern or the groove pattern with the detector, while a charging state of the common floating electrode by the irradiating electron beam is maintained.

2. The scanning electron microscope according to claim 1 , wherein the deflector or the sample stage is controlled in such a way that the electron beam is cast on a second pattern situated at a position spaced apart from a scanning area of the measurement target pattern.

3. A pattern measurement method using a scanning electron microscope, the method comprising steps of:
charging a common floating electrode which is surrounded by an insulator, and disposed in a bottom of both a measurement target pattern and a groove pattern or a hole pattern by irradiating the common floating electrode in the groove pattern or the hole pattern with the electron beam, and
forming a signal waveform by detecting electrons obtained by scanning an area including the measurement target pattern which is formed at a different position from the groove pattern or the hole pattern with the electron beam, while a charging state of the common floating electrode based on the irradiating the electron beam is maintained.

4. The pattern measurement method according to claim 3 , wherein the sample has a surface that is an electrical conductor.

5. The pattern measurement method according to claim 4 , wherein an insulator is arranged between the electrical conductor and the floating electrode.

6. A scanning electron microscope including an electron source, an objective lens which focuses an electron beam emitted from the electron source, a deflector which deflects a scanning position of the electron beam, a detector which detects electrons obtained by the scanning a sample with the electron beam, and a sample stage for loading the sample thereon, the scanning electron microscope further including a control device,
wherein the control device is configured to control at least one of the deflector and the sample stage so as to position an irradiation position of the electron beam on a measurement target pattern for forming a first signal waveform based on electrons obtained by scanning an area including the measurement target pattern,
the control device is configured to control at least one of the deflector and the sample stage so as to position the irradiation position of the electron beam on a hole pattern or a groove pattern having a common underlying pattern with the measurement target pattern for irradiating the common underlying pattern with the electron beam,
the control device is configured to control at least one of the deflector and the sample stage so as to position an irradiation position of the electron beam on the measurement target pattern so as to form a second signal waveform based on electrons obtained by scanning the area including the measurement target pattern, after irradiating the common underlying pattern in the hole pattern or the groove pattern with the electron beam,
the control device is configured to calculate a differential waveform by subtracting the second signal waveform from the first signal waveform, and
the control device is configured to measure a dimension of the measurement target pattern using the differential waveform.

7. The scanning electron microscope according to claim 6 , wherein at least one of the deflector and the sample stage is controlled in such a way that the beam is cast on a second pattern situated at a position spaced apart from a scanning area of the measurement target pattern.

8. A scanning electron microscope including an electron source, an objective lens which focuses an electron beam emitted from the electron source, a deflector which deflects a scanning position of the electron beam, a detector which detects electrons obtained by scanning a sample with the electron beam, a sample stage for loading the sample thereon, and an energy discriminator which carries out energy discrimination of electrons emitted from the sample, the scanning electron microscope further including a control device,
wherein the control device is configured to control at least one of the deflector and the sample stage so as to position an irradiating position of the electron beam on a hole pattern or a groove pattern having a common underlying pattern with a measurement target pattern for irradiating the common underlying pattern with the electron beam,
the control device is configured to control at least one of the deflector and the sample stage so as to position an irradiation position of the electron beam on a measurement target pattern so as to form a first signal waveform based on electrons obtained by scanning the area including the measurement target pattern with the electron beam under a first condition of the energy discriminator and a second signal waveform based on electrons obtained by scanning the area including the measurement target pattern with the electron beam under a second condition of the energy discriminator, after irradiating the common underlying pattern in the hole pattern or the groove pattern with the electron beam,
the control device is configured to calculate a differential waveform by subtracting the first signal waveform from the second signal waveform, and
the control device is configured to measure a dimension of the measurement target pattern using the differential waveform.

9. The scanning electron microscope according to claim 8 , wherein the second energy band has higher energy than the first energy band, and the control device is configured to subtract the first signal waveform from the second signal waveform.

10. The scanning electron microscope according to claim 8 , wherein the control device is configured to execute a dimension measurement of the pattern, using at least one of the first signal waveform, the second signal waveform, and a difference waveform obtained by subtracting the first signal waveform from the second signal waveform.

Assignees

• Hitachi High Tech Corp

Inventors

• Yokosuka Toshiyuki
• Lee Chahn
• Kazumi Hideyuki
• Makino Hiroshi
• Mizuhara Yuzuru
• Isawa Miki
• Hatano Michio
• Momonoi Yoshinori

Classifications

• H01J2237/0492

  Lens systems · CPC title

• G01B15/04

  for measuring contours or curvatures · CPC title

• H01J2237/24495

  Signal processing, e.g. mixing of two or more signals · CPC title

• H01J2237/2815

  Depth profile · CPC title

• H01J2237/281

  Bottom of trenches or holes · CPC title