Cross-section processing-and-observation method and cross-section processing-and-observation apparatus

• US 9,347,896 B2
• Filed: 09/02/2014
• Issued: 05/24/2016
• Est. Priority Date: 09/03/2013
• Status: Active Grant

• Current Assignee: Hitachi High-Tech Science Corporation (Hitachi High- Tech Corporation)
• Original Assignee: Hitachi High-Tech Science Corporation (Hitachi High- Tech Corporation)
• Inventors: Man, Xin, Asahata, Tatsuya, Uemoto, Atsushi
• Primary Examiner(s): Johnston, Phillip A
• Assistant Examiner(s): OSENBAUGH-STEWART, ELIZA W
• Application Number:
  US14/475,046
• Publication Number:
  US 20150060664A1
• Time in Patent Office: 630 Days
• US Class Current: 1/1
• CPC Class Codes: G01N 1/32 Polishing; Etching
• CPC Class Codes: G01N 2223/418 electron microscope
• CPC Class Codes: G01N 23/20091 Measuring the energy-dispersion spectrum [EDS] of diffracted radiation
• CPC Class Codes: G01N 23/2202 Preparing specimens therefor
• CPC Class Codes: G01N 23/2251 using incident electron beams, e.g. scanning electron microscopy [SEM]
• CPC Class Codes: H01J 2237/2811 Large objects
• CPC Class Codes: H01J 2237/31749 Focused ion beam
• 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
• CPC Class Codes: H01J 37/292 using scanning ray
• CPC Class Codes: H01J 37/3053 for evaporating or etching
• CPC Class Codes: H01J 37/3056 for microworking, e. g. etching of gratings or trimming of electrical components

Abstract

A cross-section processing-and-observation method, including a cross-section exposure step in which a sample is irradiated with a focused ion beam to expose a cross-section of the sample, and a cross-sectional image acquisition step in which the cross-section is irradiated with an electron beam to acquire a cross-sectional image of the cross-section. The cross-section exposure step and the cross-sectional image acquisition step are repeatedly performed along a predetermined direction of the sample at a setting interval to acquire multiple cross-sectional images of the sample. The method also includes a specific observation target detection step in which a predetermined specific observation target from the cross-sectional image acquired a the cross-sectional image acquisition step is detected. In the specific observation target detection step, after a predetermined specific observation target is detected, the setting interval of the cross-section exposure step is set to be shorter than that before the specific observation target is detected.

Claims

1. A cross-section processing-and-observation method comprising:

a cross-section exposure step of irradiating a sample with a focused ion beam to expose a cross-section of the sample;

a cross-sectional image acquisition step of irradiating the cross-section with an electron beam to acquire a cross-sectional image of the cross-section;

a step of repeatedly performing the cross-section exposure step and the cross-sectional image acquisition step along a predetermined direction of the sample at a setting interval to acquire a plurality of cross-sectional images of the sample; and

a specific observation target detection step of detecting a predetermined specific observation target from the cross-sectional image acquired at the cross-sectional image acquisition step;

wherein in the specific observation target detection step, after a predetermined specific observation target is detected, the setting interval of the cross-section exposure step is set to be shorter than that before the specific observation target is detected.

2. The cross-section processing-and-observation method according to claim 1, wherein the setting interval is equal to or an integer multiple of a pixel size of the cross-sectional image, or the pixel size is an integer multiple of the setting interval.

3. The cross-section processing-and-observation method according to claim 1, wherein

plural types of the specific observation targets are set, and

different condition setting of the cross-section exposure step and different condition setting of the cross-sectional image acquisition step are set for individual regions where the respective specific observation targets are detected.

4. The cross-section processing-and-observation method according to claim 3, wherein when the condition setting of the cross-section exposure step and the condition setting of the cross-sectional image acquisition step are set, the setting interval is equal to or an integer multiple of a pixel size of the cross-sectional image.

5. The cross-section processing-and-observation method according to claim 1, wherein in the specific observation target detection step, an EDS measurement or an EBSD measurement of the cross-section is performed.

6. The cross-section processing-and-observation method according to claim 1, wherein the specific observation target detection step includes observing a contrast change of a cross-sectional image obtained in the cross-sectional image acquisition step.

7. The cross-section processing-and-observation method according to claim 3, wherein the condition setting of the cross-section exposure step includes at least one of an accelerating voltage of the focused ion beam, a current value of the focused ion beam, an irradiation range of the focused ion beam in the sample, and a visual field range of the focused ion beam.

8. The cross-section processing-and-observation method according to claim 1, wherein the specific observation target detection step is performed once while the cross-sectional image acquisition step is performed multiple times.

9. The cross-section processing-and-observation method according to claim 1, wherein in the specific observation target detection step performed after the specific observation target is detected, cross-section processing-and-observation is not performed on other portions of the sample when the specific observation target is not detected anymore.

10. The cross-section processing-and-observation method according to claim 1, further comprising a step of forming a correction mark by irradiation of the focused ion beam,

wherein in the cross-section exposure step, an image of the correction mark is acquired with a higher magnification than a visual field range of the focused ion beam among the conditions of the cross-section exposure step.

11. The cross-section processing-and-observation method according to claim 1, further comprising a step of forming a correction mark by irradiation of the focused ion beam,

wherein in the cross-sectional image acquisition step, when the cross-sectional image is acquired, an image of the correction mark is acquired at the same time with a higher magnification than the magnification of a cross-section observation region observed by the electron beam.

12. A cross-section processing-and-observation apparatus comprising:

a sample stage on which a sample is to be placed;

a focused ion beam column configured to irradiate the sample with a focused ion beam;

an electron beam column configured to irradiate the sample with an electron beam;

one of a secondary electron detector and a backscattered electron detector configured to detect one of secondary electrons and backscattered electrons generated from the sample; and

a control unit configured to repeatedly perform a cross-section exposure step in which the sample is irradiated with a focused ion beam emitted from the focused ion beam column to expose a cross-section of the sample, and a cross-sectional image acquisition step in which the cross-section is irradiated with an electron beam emitted from the electron beam column to acquire a cross-sectional image of the cross-section along a predetermined direction of the sample at a setting interval;

wherein the control unit is further configured to periodically perform a specific observation target detection step of detecting a predetermined specific observation target from the cross-sectional image acquired at the cross-sectional image acquisition step; and

wherein in the specific observation target detection step, after a predetermined specific observation target is detected, the setting interval of the cross-section exposure step is set to be shorter than that before the specific observation target is detected.

13. The cross-section processing-and-observation apparatus according to claim 12, wherein the control unit controls the setting interval to be equal to or an integer multiple of a pixel size of the cross-sectional image or controls the pixel size to be an integer multiple of the setting interval.