Charged particle beam device and measuring method using the same

Patent metadata

Field	Value
Publication number	US-9336984-B2
Application number	US-201414244802-A
Country	US
Kind code	B2
Filing date	Apr 3, 2014
Priority date	Apr 3, 2013
Publication date	May 10, 2016
Grant date	May 10, 2016

Abstract

In an SEM provided with an ExB deflector for deflecting secondary electrons outside an optical axis of a primary electron beam between an electronic source and an object lens for condensing the primary electron beam and irradiating a sample with the beam, a unit to decelerate the secondary electrons deflected in the ExB deflector, and a magnetic generator for deflecting the decelerated secondary electron are provided, and a plurality of energy filters and detectors are arranged around the magnetic generator. That is, by separating loci of the secondary electrons incident on the energy filters and of the secondary electrons reflected at the energy filters by the magnetic generator, both of the secondary electrons are concurrently detected.

First claim

What is claimed is:

1. A charged particle beam device comprising:
a charged particle source configured to generate a charged particle beam;
a first deflector configured to deflect the charged particle beam from the charged particle source;
a condenser lens configured to condense the charged particle beam;
a stage configured to hold a sample to be irradiated with the charged particle beam;
a power source unit configured to apply a retarding voltage that decelerates the charged particle beam to the sample or the stage;
a second deflector configured to deflect secondary electrons from the sample outside an optical axis of the charged particle beam;
a first grid configured to allow an electron to pass through or reflect the electron according to an energy of the electron;
a first detector configured to detect a secondary electron that has passed through the first grid;
a second detector configured to detect a secondary electron that has been reflected at the first grid;
a magnetic generator configured to deflect the secondary electron that has passed through the first grid and the secondary electron that has been reflected at the first grid; and
a decelerating electrode that decelerates the secondary electrons, the decelerating electrode being positioned in a path between the second deflector and the first detector and configured from a conductor to have openings for allowing the secondary electrons to pass through three places.

2. The charged particle beam device according to claim 1 , comprising a control unit that controls a voltage to be applied to the decelerating electrode according to the retarding voltage.

3. The charged particle beam device according to claim 1 , comprising:
a second grid that allows an electron to pass through or reflects the electron according to energy of the electron, wherein
the second grid is provided in a path between the magnetic generator and the second detector.

4. The charged particle beam device according to claim 3 , further comprising a third detector that detects the secondary electron that has been reflected at the second grid.

5. The charged particle beam device according to claim 3 , wherein the magnitude of an electric field formed in the second grid is smaller than the magnitude of an electric field formed in the first grid.

6. The charged particle beam device according to claim 1 , wherein a magnetic shield is included between an optical axis of the charged particle beam and the magnetic generator.

7. The charged particle beam device according to claim 1 , wherein an electric field shield of a ground conductor is included between an optical axis of the charged particle beam and the magnetic generator.

8. A length measuring method using the charged particle beam device according to claim 1 , the method comprising:
forming a first image by a signal obtained in the first detector;
forming a second image by a signal obtained in the second detector; and
measuring a dimension of a pattern of the sample from each of the first image and the second image, wherein
measuring points of the dimension of the sample are different in the first image and the second image.

9. A length measuring method using the charged particle beam device according to claim 4 , the method comprising:
forming a first image by a signal obtained in the first detector;
forming a second image by a signal obtained in the second detector;
forming a third image by a signal obtained in the third detector; and
measuring a dimension of a pattern of the sample from each of the first image, the second image, and the third image, wherein measuring points of the dimension of the sample are different from each other in the first image, the second image, and the third image.

Assignees

• Hitachi High Tech Corp

Inventors

• Bizen Daisuke
• Kawano Hajime
• Kazumi Hideyuki

Classifications

• H01J2237/2448

  Secondary particle detectors · CPC title

• H01J37/244

  Detectors; Associated components or circuits therefor · CPC title

• H01J2237/2449

  Detector devices with moving charges in electric or magnetic fields · CPC title

• H01J2237/2806

  Secondary charged particle · CPC title

• H01J2237/281

  Bottom of trenches or holes · CPC title