CHARGED PARTICLE BEAM APPARATUS AND METHOD OF CORRECTING LANDING ANGLE OF CHARGED PARTICLE BEAM

• US 20150053855A1
• Filed: 11/06/2012
• Published: 02/26/2015
• Est. Priority Date: 11/08/2011
• Status: Active Grant

• Current Assignee: Hitachi High-Tech Company Limited (Hitachi, Ltd.)
• Original Assignee: Hitachi High-Technologies Corporation (Hitachi, Ltd.)
• Inventors: Shirai, Masumi
• Granted Patent: US 9,679,744 B2
• Time in Patent Office: Days
• US Class Current: 250/307
• CPC Class Codes: G01B 15/00 Measuring arrangements characterised by the use of electromagnetic waves or particle radiation, e.g. by the use of microwaves, X-rays, gamma rays or electrons characterised by the use of optical techniques G01B9/00, G01B11/00
• CPC Class Codes: H01J 2237/2806 Secondary charged particle
• CPC Class Codes: H01J 2237/2809 characterised by the imaging problems involved
• CPC Class Codes: H01J 2237/2817 Pattern inspection
• CPC Class Codes: H01J 37/147 Arrangements for directing or deflecting the discharge along a desired path H01J37/045 take precedence; lenses H01J37/10
• CPC Class Codes: H01J 37/20 Means for supporting or positioning the object or the material; Means for adjusting diaphragms or lenses associated with the support
• CPC Class Codes: H01J 37/22 Optical , image processing or photographic arrangements associated with the tube
• CPC Class Codes: H01J 37/222 Image processing arrangements associated with the tube
• CPC Class Codes: H01J 37/28 with scanning beams H01J37/268, H01J37/292, H01J37/2955 take precedence

Abstract

A scanning electron microscope (SEM) is configured so that SEM images are acquired while scanning a pyramid pattern on a sample plane from four directions. Landing angle of the electron beam is calculated from these SEM images, which are then averaged, whereby inclination angle of the electron beam that is less influenced from scan distortion can be found.

Claims

1. A charged particle beam apparatus, comprising:

an image acquisition unit that acquires a charged particle beam image of a polyhedral structure having a known shape that is formed on a sample plane while changing a scanning direction of a charged particle beam or a loading direction of a sample in which the polyhedral structure is disposed between mutually opposed directions;

a landing angle measurement unit that measures landing angle of a charged particle beam with respect to the sample for each charged particle beam image of the polyhedral structure acquired by the image acquisition unit when acquiring the charged particle beam image based on a geometric deformation of the polyhedral structure on the image; and

a measurement error suppression unit that averages landing angles of the charged particle beam images of the polyhedral structure measured by the landing angle measurement unit, and corrects inclination angle of a charged particle beam image by the image acquisition unit based on the averaged landing angle.

2. The charged particle beam apparatus according to claim 1, wherein

the image acquisition unit changes rotation angle as in 0°

, 180°

, 90° and

270°

by raster rotation, and acquires a charged particle beam image of the polyhedral structure corresponding to each rotation angle in an image shift manner.

3. The charged particle beam apparatus according to claim 1, wherein the image acquisition unit changes wafer loading angle of the sample as in 0°

and 180°

, and acquires a charged particle beam image of the polyhedral structure corresponding to each wafer loading angle in an image shift manner.

4. The charged particle beam apparatus according to claim 2, wherein the measurement error suppression unit averages landing angles of charged particle beam images of the polyhedral structure that are measured by the landing angle measurement unit, and averages characteristics of relationships between image shift amounts and inclination angles of charged particle beams during the image shift, corresponding to the landing angles of charged particle beam images of the polyhedral structure that are measured by the landing angle measurement unit, thus correcting inclination angle of a charged particle beam image by the image acquisition unit based on the averaged landing angle and characteristics of relationships.

5. A method of correcting landing angle, comprising the steps of:

acquiring a charged particle beam image of a polyhedral structure having a known shape that is formed on a sample plane while changing a scanning direction of a charged particle beam or a loading direction of a sample in which the polyhedral structure is disposed between mutually opposed directions;

measuring landing angle of a charged particle beam with respect to the sample for each charged particle beam image of the polyhedral structure that is acquired by the acquiring the charged particle beam image when acquiring the charged particle beam image based on a geometric deformation of the polyhedral structure on the image; and

averaging landing angles of the charged particle beam images of the polyhedral structure measured by the measuring land angle, and corrects inclination angle of a charged particle beam image by the acquiring the charged particle beam image based on the averaged landing angle.