JP4654216B2 - Sample holder for charged particle beam equipment - Google Patents

Description

  The present invention relates to a sample holder that holds an object to be irradiated with a charged particle beam, and in particular, a fine sample piece is extracted from a sample by a focused ion beam (hereinafter referred to as FIB) processing apparatus, and the extracted fine sample piece is fixed to a sample stage and processed. The present invention relates to a sample holder for a charged particle beam apparatus that enables thin film processing by a focused ion beam from an arbitrary direction of an extracted micro sample and observation of an electron microscope from the arbitrary direction of the sample when observing.

  Conventionally, for example, JP-A-7-134963 and JP-A-6-103947 have been disclosed as examples of pretreatment of a sample by a focused ion beam apparatus and subsequent observation. In this technique, the sample processed by the focused ion beam apparatus can be inserted into an observation apparatus such as a pretreatment apparatus or a transmission electron microscope (hereinafter referred to as TEM) without changing the sample. However, in these apparatuses, only the center axis of the sample holder can be rotated, and once the sample is mounted, the sample only rotates around the sample holder axis. For this reason, it is impossible to rotate the sample around an axis perpendicular to the sample holder axis, or to rotate the sample in a plane parallel to and perpendicular to the central axis. Adjustment was difficult.

  In addition, there is a holder that can tilt the sample in the α and β biaxial directions as disclosed in Japanese Patent Application Laid-Open No. 2000-40483, but this type of holder also has a sample tilt of about 20 °, and the sample can be rotated 360 ° to obtain an arbitrary tilt. It was difficult to observe from the direction.

JP-A-7-134963 JP-A-6-103947 JP 2000-40383 A

  An object of the present invention is to process a micro sample extracted by a focused ion beam processing method or the like from an arbitrary direction or to observe from an arbitrary direction by an electron microscope. It is another object of the present invention to provide a sample holder for a charged particle beam apparatus that can find, process, and analyze a minute defect portion that has been overlooked without missing.

  The above object is achieved by providing a sample holder for a charged particle beam apparatus having a function of rotating a sample stage on which a sample is fixed around the optical axis of a focused ion beam.

  Further, the above object is achieved by providing a function of rotating a sample stage, on which a sample is fixed, around a holder axis in the sample holder for a charged particle beam apparatus.

  Further, the above object is achieved by providing the sample holder for the charged particle beam apparatus with a function capable of rotating a sample fixed at a right angle to the traveling direction of the electron beam with the electron beam optical axis as a center and rotating 360 °. The

  Further, the above object is that the charged particle beam apparatus sample holder has a function of rotating a sample fixed at a right angle to the traveling direction of the focused ion beam by 360 ° with the focused ion beam optical axis as the center. Achieved.

  By using the sample holder for a charged particle beam apparatus according to the present invention, a sample is processed by an ion beam from an arbitrary direction and observed by an electron beam from an arbitrary direction without removing a minute sample piece from the sample stage. It becomes possible.

  The present invention will be described below with reference to the drawings. FIG. 1 is a basic configuration diagram of a transmission electron microscope (hereinafter abbreviated as TEM) mirror body 1 according to an embodiment of the present invention. The TEM mirror 1 includes an electron gun 2, an irradiation lens 3, an objective lens 4, and a projection lens 5. A scanning coil 6 is disposed between the irradiation lens 3 and the objective lens 4, and a sample 7 is inserted below the scanning coil 6. The sample 7 is attached to the sample holder 8, and the sample holder 8 is connected to the holder control unit 9. A secondary electron detector 10 is incorporated above the sample 7 and below the scanning coil 6. The secondary electron detector 10 is connected to the scanning image display device 11. An annular detector 12 for observing the dark field STEM image is disposed below the projection lens 5. The annular detector 12 is connected to the scanned image display device 11. A detector 13 (for bright field STEM image observation) that can be taken in and out of the electron beam axis is provided below the annular detector 12 and is connected to the scanning image display device 11. A transmission image observation TV camera 14 is disposed below the detector 13. The TV camera 14 is connected to the TV monitor 16 via the TV camera control unit 15.

The electron beam 17 is converged in a spot shape on the surface of the sample 36 by the irradiation lens 3, and the surface of the sample 7 is scanned by the scanning coil 6. The secondary electron detector 10 detects secondary electrons emitted from the sample 7 by irradiation of the electron beam 17, and the scanning image display device 11 displays a secondary electron image of the scanning region of the electron beam 17 of the sample 7. indicate. In the detector 13, the angle from the sample 7 is about 50 half-widths.
The transmitted electron scattered within mrad is detected, and the bright field transmitted electron image is displayed by the scanning image display device 11. The same applies to the annular detector 12. Electrons (elastically scattered electrons) scattered from the sample 7 in the range of a half angle of about 80 to 500 mrad by the irradiation of the electron beam 17 are detected, and the scanning image display device 11 performs detection. A dark field transmission electron image is displayed. Further, by changing the conditions of the irradiation lens 3, an electron beam 17 having a certain spread is irradiated on the surface of the sample 7, and the electrons transmitted through the sample 7 are imaged by the objective lens 4, and the image is projected. The image is magnified by the lens 5 and projected onto the TV camera 14. The projected transmission electron image is displayed on the TV monitor 16 via the TV camera control unit 15. The angle of the sample 7 can be changed on the electron beam optical axis by the holder control unit 9 connected to the sample holder 8, and the secondary electron image, the scanning transmission image, and the transmission electron image can be observed from various angles. Is possible.

FIG. 2 shows a configuration diagram of the FIB apparatus 18. The FIB device 18 mirror body includes an ion gun 19, a condenser lens 20, a diaphragm 21, a scanning electrode 22, and an objective lens 23. In the sample chamber of the FIB apparatus 18, a secondary electron detector 24 above the sample holder 8 to which the sample 7 is attached, a deposition gun 25 for forming a protective film on the sample 7 and fixing the sample 7 to the sample stage. ,
A microprobe 26 for transporting a micro sample produced by FIB processing is attached. A scanning image display device 27 is connected to the secondary electron detector 24. The scanning image display device 27 is connected to the scanning electrode 22 via the scanning electrode control unit 28. The microprobe 26 is connected to a microprobe control device 29 for controlling the position of the microprobe 26. The sample holder 8 is connected to the holder control unit 9. The ion beam 30 emitted from the ion gun 19 is converged by the condenser lens 20 and the diaphragm 21, passes through the objective lens 23, and converges on the sample 7. The scanning electrode 22 above the objective lens 23 deflects and scans the ion beam 30 incident on the sample 7 according to an instruction from the scanning electrode control unit 28. When the sample 7 is irradiated with the ion beam 30, the sample 7 is sputtered and generates secondary electrons. The generated secondary electrons are detected by the secondary electron detector 24 and displayed on the scanning image display device 27. The gas emitted from the deposition gun 25 toward the sample 7 reacts with the ion beam 30 and is decomposed, and metal is deposited on the ion beam 30 irradiation region on the surface of the sample 7. This deposited film is used to form a protective film on the surface of the sample 7 before FIB processing and to fix a minute sample piece to the sample stage. The angle of the sample 7 can be changed on the optical axis of the ion beam 30 by a holder control unit 9 connected to the sample holder 8, and the sample 7 can be processed from various angles.

FIG. 3 shows a top view (a) and a cross-sectional view (b) of the tip of a sample holder 8 for a charged particle beam apparatus according to an embodiment of the present invention. The sample holder 8 has a mechanism in which a holder shaft 31 connected to the tip portion can rotate 360 ° around the center of the shaft, and the bevel gear 32 (first bevel gear 32) is provided at the tip portion independently of the mechanism. ) Has another rotating shaft 33 inside the holder shaft 31. The sample rotation shaft 33 is connected to the holder control unit 9, and the sample rotation shaft 33 and the bevel gear 32 are rotated by the holder control unit 9. The bevel gear 32 and the bevel gear 34 (second bevel gear) are in contact with each other, and by rotating the sample rotating shaft 33, the bevel gear 32 rotates and at the same time the bevel gear 34 rotates. Further, the sample holder 8 has a structure in which a part of the structure of the holder 8 is released so that the structure of the holder 8 does not block the ion beam 30 when the ion beam 30 is incident in the FIB apparatus 18.

  FIG. 4 is a side view (a) and a perspective view (b) of a sample stage 35 according to an embodiment of the present invention. A side view and a perspective view in a state where the minute sample piece 36 is fixed to the sample stage 35 are shown in (c) and (d), respectively. The minute sample piece 36 is attached to the tip of the sample table 35. The tip of the sample stage 35 has a flat shape so that the minute sample piece 36 can be easily fixed. A deposition film 37 is formed and adhered to the contact portion between the minute sample piece 36 and the sample stage 35 by using the deposition gun 25 of the FIB apparatus 18.

FIG. 5A shows a sample stage 35 and a sample holder 8 for a charged particle beam apparatus according to an embodiment of the present invention.
The example which fixed (sample support part) is shown. The bevel gears 32 and 34 are hollow and can be mounted so as to insert the sample table 35. When processing by FIB, the sample stage 35 is attached to the bevel gear 34, the sample holder 8 is inserted into the FIB apparatus 18, and the ion beam 30 is incident from above the sample stage 35 to process the minute sample piece 36. When the sample stage 35 is rotated while the ion beam 30 remains at one point, the cylindrical minute sample piece 36 can be processed. When the processing is completed, the holder shaft 31 itself is rotated by 90 °, the holder 8 is inserted into the sample chamber of the transmission electron microscope 1, and the electron beam 17 is incident from the side surface of the sample stage 35. That is, the transmission image is observed by making the electron beam 17 incident on the paper surface from the vertical direction. At this time, the bevel gear 34 is rotated by moving the sample rotating shaft 33, and it is possible to observe from the direction of 360 ° around the sample 36. Further, the sample stage 35 may be replaced as shown in FIG. Thereby, it is possible to select a direction in which X-ray extraction can be efficiently performed during X-ray analysis.

  In the above description, the example in which the sample stage 35 is fixed to the bevel gear 34 has been described. Of course, the sample stage 35 may be attached to and detached from the bevel gear 34. By making it possible to attach and detach, it is possible to adopt a sample stage according to processing and observation conditions.

  FIG. 6 shows the positional relationship between the ion beam 30 and the electron beam 17 with respect to the minute sample piece 36. At the time of processing, as shown in (a, b), the ion beam 30 is incident from above the minute sample piece 36 and processed into an arbitrary shape such as a prism or a cylinder. After the processing, the electron beam 17 is incident from a direction perpendicular to the direction in which the ion beam 30 of the minute sample piece 36 is incident by the transmission electron microscope 1 and the inside is observed. Here, if the secondary electron image is used, information on the surface of the sample 36 can be obtained, and the internal structure can be observed by using the scanning transmission electron image. In addition, since the sample 36 can be rotated, observation from all directions is possible, and the positional relationship of the structure inside the sample can be captured three-dimensionally.

FIG. 7 shows a top view (a) and a side view (b) of the tip of a sample holder 8 for a charged particle beam apparatus according to another embodiment of the present invention. The sample holder 8 is provided with a mechanism for rotating the holder shaft 31 itself connected to the tip, bevel gears 32 and 38. The entire tip of the holder 8 can be rotated 360 ° around the axis. A bevel gear 32 is provided at the tip of the sample rotation shaft 33. Further, since the bevel gear 32 and the bevel gear 38 are in contact with each other, the bevel gear 38 can be rotated 360 ° by operating the sample rotating shaft 33. The sample table 35 is mounted on a fixed table 39 on the bevel gear 38. The minute sample piece 36 is attached to the tip of the sample table 35.

A processing method of the sample 36 will be described with reference to FIG. When processing the sample 36 by FIB, the holder shaft 31 of the sample holder 8 is rotated so that the ion beam 30 is incident from above the sample stage 35, and the bevel gear 38 is partially rotated. As a result, for example, in the case of a sample made of a material having a different etching rate, such as a semiconductor device, a difference occurs in the sample thickness, so that a so-called processing stripe is generated. However, by processing the sample while rotating the sample to change the incident direction of the ion beam 19 as in the present embodiment, a sample having a uniform thickness can be manufactured without processing lines. The produced sample 36 is shown in FIG.
As shown in (b), the electron beam 17 is made incident, and the secondary electron image and the transmitted image are observed.

  As shown in FIG. 8, the structure of the fixed base 39 may be such that the sample base 35 can be removed and the sample base 35 can be attached from two directions. (A) is a top view (b), (c) is a side view. The sample table 35 can be mounted on the fixed table 39 in parallel with the incident direction of the ion beam 30 as shown in FIG. 7B, and the sample table 35 is mounted perpendicular to the incident direction of the electron beam 17 as shown in FIG. it can. Thereby, FIB processing and electron microscope observation can be performed even if the holder shaft 31 itself of the sample holder 8 has no rotation mechanism.

1 is a basic configuration diagram of a TEM apparatus according to an embodiment of the present invention. 1 is a basic configuration diagram of an FIB apparatus according to an embodiment of the present invention. The top view and sectional drawing of the sample holder tip part for charged particle beam devices which are one example of the present invention. The side view and perspective view of the sample stand for charged particle beam apparatuses which are one Example of this invention. The top view of the sample holder front-end | tip part for charged particle beam apparatuses which is one Example of this invention. Explanatory drawing of sample processing and observation method at the time of this invention implementation. The top view and side view of the sample holder front-end | tip part for charged particle beam apparatuses which are one Example of this invention. The top view and side view of the sample holder front-end | tip part for charged particle beam apparatuses which are one Example of this invention.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 ... Transmission electron microscope, 2 ... Electron gun, 3 ... Irradiation system lens, 4, 23 ... Objective lens, 5 ... Projection lens, 6 ... Scanning coil, 7 ... Sample, 8 ... Sample holder, 9 ... Holder control part, 10 , 24 ... Secondary electron detector, 11, 27 ... Scanned image display device, 12 ... Annular detector for dark field STEM image observation, 13 ... Bright field detector, 14 ... TV camera, 15 ... TV camera control unit, 16 ... TV monitor, 17 ... electron beam, 18 ... FIB device, 19 ... ion gun, 20 ... condenser lens, 21 ... aperture, 22 ... scanning electrode, 25 ... deposition gun, 26 ... microprobe, 28 ... scanning electrode control 29: Microprobe control device, 30 ... Ion beam, 31 ... Holder shaft, 32, 34, 38 ... Bevel gear, 33 ... Sample rotating shaft, 35 ... Sample stand, 36 ... Micro sample piece, 37 ... Deposition , 39 ... fixed base.

Claims (7)

The charged particle beam irradiation apparatus is configured to be insertable from the side of the mirror body, and can be rotated 360 ° around the axis center of the holder axis perpendicular to the charged particle beam optical axis, and with respect to the holder axis A method for processing and observing a small sample piece using a sample holder provided with a sample stage that can rotate 360 ° about a vertical arbitrary rotation axis ,
In the sample chamber of the ion beam apparatus in which the sample holder is inserted, a micro sample piece extracted by ion beam processing is placed on the ion beam optical axis so that the micro sample piece is on the axis center of the holder axis. It is possible to change the angle of the micro sample piece on the ion beam optical axis so as to be held on the sample stage,
On the ion beam optical axis, the micro sample piece is rotated around at least a rotation axis parallel to the ion beam optical axis to irradiate the micro sample piece with the ion beam, and the micro sample piece is ionized from an arbitrary direction. Processed by beam,
The sample holder holding the micro sample piece processed by the ion beam is inserted into a transmission electron microscope, and the micro sample piece processed by the ion beam is inserted into the axis of the holder axis in the sample chamber of the transmission electron microscope. It is possible to change the angle of the micro sample piece on the center and on the electron beam optical axis, on the electron beam optical axis,
On the electron beam optical axis, and irradiates an electron beam onto the micro-sample piece by rotating the micro sample piece about a vertical axis of rotation at least in the electron beam, the micro sample piece in any direction or al method of observing transparently electron microscope. It is the processing observation method of the micro sample piece according to claim 1,
A method characterized by ion beam processing the minute sample piece extracted by ion beam processing into a prismatic shape. It is the processing observation method of the micro sample piece according to claim 1,
A method characterized by ion beam processing the minute sample piece extracted by ion beam processing into a cylindrical shape. It is the processing observation method of the micro sample piece according to claim 1,
On the ion beam optical axis, the minute sample piece is rotated around a rotation axis perpendicular to the ion beam optical axis to irradiate the sample piece with the ion beam, and the minute sample piece is changed while changing the incident direction of the ion beam. A method characterized by processing. It is the processing observation method of the micro sample piece according to claim 1,
In the transmission electron microscope, a scanning transmission image of the minute sample piece is observed. It is the processing observation method of the micro sample piece according to claim 1,
A method of observing a transmission electron image of the minute sample piece in the transmission electron microscope. It is the processing observation method of the micro sample piece according to claim 1,
In the transmission electron microscope, the positional relationship of the internal structure of the minute sample piece is captured three-dimensionally.

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