JP2010133739A - Observation sample preparation method and observation sample preparation device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an observation sample preparation method and an observation sample preparation device capable of preparing an observation sample having high uniformity of thickness, and including a vacuum domain at a desired distance from an observation portion. <P>SOLUTION: An FIB (Focused Ion Beam) is irradiated from a non-structure part 72 side of a processing object sample 7 having two parts, namely, a structure part 71 on which at least a pattern is formed and the non-structure part 72 on which the pattern is not formed, and an observation object surface for observing a structure of the processing object sample 7 is formed by processing a side face including an interface between the structure part 71 and the non-structure part 72, and the processing object sample 7 is processed by irradiating the FIB from a direction along the observation object surface. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a method for preparing an observation sample to be observed with an electron beam image and a preparation apparatus for the observation sample.

  In recent years, electron holography, which excels at observing electric and magnetic fields, has attracted attention. For example, also in the semiconductor field, this electron beam holography method is expected as a method for visualizing the structure of the source and drain in a transistor that is difficult to visualize with a conventional electron microscope or the like.

  The electron holography method is a method in which an interference image between an electron beam transmitted through a sample and an electron beam transmitted through a vacuum is observed, and the sample structure is visualized from a slight phase shift. Therefore, in the observation sample to which the electron holography method is applied, the uniformity of the thickness is very important, and a region (vacuum region) having no substance in the vicinity of the observation site is necessary.

  As a method of taking out only an arbitrary part of an integrated circuit chip or a semiconductor wafer as a sample used for such observation, an analysis part including the observation part of the chip or wafer is supported by a probe, and the surface of the chip or wafer is supported. A technique for separating an analysis portion by irradiating an ion beam from two directions having different angles is known (see Patent Document 1 and the like).

Japanese Patent No. 2774884

  In the observation sample observed by the electron holography method, the analysis part (primary sample) separated by the above-mentioned conventional technique is further processed, and the observation sample (appropriate with the uniformity of the sample thickness and the positional relationship between the observation site and the vacuum region) Secondary sample) must be prepared.

  However, when an observation sample is prepared using an ion beam, if the sample is prepared while observing secondary electrons generated by the ion beam irradiated to the sample as an image, the observation site of the sample is destroyed by the ion beam, and the sample is not observed. It becomes difficult.

  The present invention has been made in view of the above, and an observation sample preparation method and an observation sample preparation capable of preparing an observation sample having high uniformity in thickness and having a vacuum region at a desired distance from an observation site. An object is to provide an apparatus.

  In order to achieve the above object, the present invention irradiates a charged particle beam from the non-structure part side of a sample to be processed having at least two parts of a structure part where a pattern is formed and a non-structure part where a pattern is not formed. Then, a side surface including the interface between the structure portion and the non-structure portion is processed to form an observation target surface for observing the structure of the sample to be processed, and the charged particle beam is irradiated from a direction along the observation target surface. Thus, the sample to be processed is processed.

  In the present invention, it is possible to produce an observation sample having high thickness uniformity and having a vacuum region at a desired distance from the observation site.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  First, regarding the principle of electron beam holography, which is an example of an observation method of an observation sample according to the present embodiment, the electron beam holography method is applied to structure observation of a semiconductor element (for example, MOSFET: Metal Oxide Semiconductor Field Effect Transistor). This will be described as an example.

  The electron beam holography method is a technique for observing a sample using a TEM (Transmission Electron Microscope), and irradiates an observation part of the observation sample with an electron beam in a vacuum and transmits the sample through the sample (hereinafter referred to as an object wave). ) And an electron beam (hereinafter referred to as a reference wave) that has passed through a portion without a sample (in a vacuum) is interfered by a biprism or the like, and a slight potential difference (potential distribution) inside the sample due to a change in the phase or the like. Is a method for visualizing the structure inside the sample as an interference fringe image (hereinafter referred to as a phase image).

  Therefore, in the observation sample to which the electron holography method is applied, it is necessary to provide a range (vacuum region) through which the reference wave passes in the vicinity of the observation site. In addition, the uniformity of the sample film thickness (thickness in the traveling direction of the reference wave) of the observation sample is related to the accuracy of the phase image, and the closer the sample film thickness is, the higher the accuracy of the phase image.

  FIG. 1 is a diagram showing a phase image when both an object wave and a reference wave pass through a vacuum in an electron beam holography method, that is, when an observation sample is not used.

  In FIG. 1, the phase image (interference fringe image) by the electron beam holography method shows a monotonous striped image, that is, it is visually confirmed that there is no phase difference between the object wave and the reference wave. Can be confirmed.

  FIG. 2 is a diagram schematically showing a cross section of a MOSFET as an example of an observation sample to which the electron beam holography method is applied.

  In FIG. 2, a MOSFET (hereinafter simply referred to as a transistor) includes a silicon substrate 11, a source 12, a drain 13 and a gate 15 formed on the silicon substrate 11, and a gate 15 and a silicon substrate 11 (source 12 and An insulating film 14 that electrically insulates (including the drain 13), a metal wiring 17, and a contact plug 16 that electrically connects the metal wiring 17 and the drain 13.

  The source 12 and the drain 13 are formed by implanting ions (for example, arsenic or boron) into the silicon substrate 11. The amount of ions implanted into the source 12 portion or the drain 12 portion of the silicon substrate 11 is very small. For example, the amount of ions is about 10 ^ 21 (pieces / cm ^ 3).

  FIG. 3 is a diagram schematically showing the relationship between the phase image (interference fringe image) and the transistor structure when the electron beam holography method is applied to the transistor shown in FIG. The interference fringes 18 in FIG. 3 schematically show the interference fringes in the phase image (interference fringe image).

  FIG. 3 shows a case where an observation site (for example, a site where the source 12 and the drain 13 are formed) in the transistor is located near the center of the phase image (interference fringe image).

  A range corresponding to the interference fringes 18 in the transistor, that is, a range shown in the phase image (hereinafter referred to as an observation range) is a range of a width L (for example, 50 nm to 200 nm). A phase difference caused by the structure of the transistor (potential difference, potential distribution) appears in the interference fringes 18 (phase image) in this observation range, whereby the structure of the transistor is visualized.

  Here, in the electron beam holography method as described above, an electron beam (object wave) that has passed through the observation range of the transistor and an electron beam (reference wave) that has passed through a vacuum region provided in the vicinity of the electron beam are applied to a biprism or the like. In order to obtain a phase image (interference fringe image) from these phase differences, a vacuum region (region through which a reference wave passes) is provided in the vicinity of the observation region in the observation range.

  As the position of the vacuum region with respect to the observation range, for example, the range adjacent to the upper side (gate 15 side) of the range (observation range) corresponding to the interference fringes 18 of the transistor, or the lower side of the observation range (silicon substrate 11 side) A vacuum region is provided in a range adjacent to the. Further, as the positional relationship between the vacuum region and the observation region, in order to adjust the observation region to be located near the center of the observation range (interference fringe 18) having a width L (for example, 100 nm), it is approximately L from the observation region. A vacuum region is provided at a distance of / 2 (for example, 50 nm).

  4 is a diagram showing a phase image of the electron holography method in the transistor having the structure as shown in FIG. 2, and FIG. 5 is a diagram showing an image (transmission image or the like) obtained by imaging the transistor by a normal TEM method. It is.

  In FIG. 4, an observation site in the transistor structure shown in FIGS. 2 and 3 is imaged, and from this, the structure (formation state) of the source 12 and the drain 13 in the transistor can be visually confirmed. On the other hand, in FIG. 5, it is difficult to visually confirm the structure of the source 12 and the drain 13 in the transistor.

  Next, the sample preparation apparatus in this embodiment will be described.

  FIG. 6 is a diagram showing the overall configuration of the sample preparation apparatus in the present embodiment.

In FIG. 6, the sample preparation apparatus includes a vacuum vessel 1, a charged particle beam (ion beam) column 2 and a charged particle beam (electron beam) column 3 disposed in the vacuum vessel 1,
A sample stage 4 on which a sample to be processed (not shown, see FIG. 7 later) is placed, and a secondary electron detector that detects secondary electrons emitted from the sample to be processed by irradiation of the sample with the electron beam 5 and a control device (control PC) 6 for controlling the operation of the entire sample manufacturing apparatus.

  The charged particle beam column 2 (hereinafter referred to as an ion beam column 2) includes an ion gun 21 that generates an ion beam (for example, a Ga ion beam), a lens 22 that focuses the ion beam, and a deflection of the ion beam. And a deflection coil 23. In addition, in order to suppress complication of drawing, illustration of the connection relationship between the ion gun 21 and the lens 22 and the control device 6 in the ion beam column 2 is omitted.

  The charged particle beam column 3 (hereinafter referred to as an electron beam column 3) includes an electron gun 31 that generates an electron beam, a lens 32 that focuses the electron beam, and a deflection coil 33 that deflects the electron beam. ing.

  In addition, in order to suppress complication of drawing, illustration of the connection relationship between the ion gun 21 and the lens 22 and the control device 6 in the ion beam column 2 is omitted. Similarly, the connection relationship between the electron gun 31 and the lens 32 and the control device 6 in the electron beam column 3 is not shown.

  The sample stage 4 is a sample stage 41 for fixing a sample to be processed (not shown, see FIG. 7 later) on its mounting surface, and the sample stage 41 is rotationally driven around the sample fixing position. The first sample rotating mechanism 42 and the second sample rotating mechanism 43 that integrally rotate and drive the sample to be processed and the sample stage 41 are provided.

  The first sample rotation mechanism 42 rotates the sample stage 41 with respect to each component (for example, the ion beam column 21 or the electron beam column 31) of the sample preparation apparatus. The first sample rotation mechanism 42 passes through the sample to be processed placed on the sample table 41 and is perpendicular to the optical axis of the ion beam irradiated from the ion beam column 21 to the sample to be processed. The sample to be processed is rotationally driven together with the sample stage 41 and the second sample rotation mechanism 43 around the rotation axis 44 in the direction along the mounting surface.

  The second sample rotation mechanism 43 rotates the sample stage 41 with respect to the first sample rotation mechanism 42. The second sample rotation mechanism 43 passes through the sample to be processed placed on the sample stage 41, has a rotation axis 45 perpendicular to the rotation axis 44 of the first sample rotation mechanism 42 and perpendicular to the difference surface of the sample stage 41. The sample to be processed is rotationally driven together with the sample table 41 at the center.

  By rotating and driving the sample stage 41 by the first sample rotation mechanism 42 and the second sample rotation mechanism 43, the orientation of the sample to be processed fixed to the mounting surface of the sample stage 41 is changed with respect to each component of the sample preparation apparatus. To change.

  The control device (control PC) 6 controls the overall operation of the sample preparation device. For example, the ion beam column 2 and the electron beam column 3 are based on information input from an input device (not shown). The operation of the first and second sample rotating mechanisms 42 and 43 of the sample stage 4 is controlled.

  The control device 6 uses the secondary electron detector 5 to detect secondary electrons generated from a sample (for example, a sample to be processed) placed on the sample stage 41 by the ion beam irradiated from the ion beam column 2, A SIM (Scanning Ion Microscope) image is calculated from the control information of the deflection coil 23 of the ion beam column 2 and the detection information from the secondary electron detector 5 and displayed on the display device 61.

  Further, the control device 6 uses the secondary electron detector 5 to detect secondary electrons generated from a sample (for example, a sample to be processed) placed on the sample table 41 by the electron beam irradiated from the electron beam column 3. Then, an SEM (Scanning Electron Microscope) image is calculated from the control information of the deflection coil 33 of the electron beam column 3 and the detection information from the secondary electron detector 5 and displayed on the display device 61.

  Further, the control device 6 deflects an ion beam (FIB: Focused Ion Beam) focused by the lens 22 of the ion beam column 2 by the deflection coil 23 and irradiates the sample to be processed placed on the sample stage 41. FIB processing is performed.

  The preparation procedure of the observation sample in the present embodiment configured as described above will be described.

  FIG. 7 is a diagram showing a procedure for preparing an observation sample by the sample preparation apparatus of the present embodiment. In FIG. 7, as an example, a state in which the sample 7 to be processed is placed on the sample stage 41 is shown. In FIG. 7, the upward direction corresponds to the direction of the ion beam column 2. Further, the direction perpendicular to the paper surface corresponds to the direction of the rotation axis 44 of the first sample rotation mechanism 42.

  In FIG. 7, a processing target sample 7 is an analysis portion including an observation portion (for example, a formation portion of the source 12 and the drain 13 in the transistor of FIG. 2) in an integrated circuit chip or a semiconductor wafer. An observation sample used for observation by electron holography is prepared.

  The sample 7 to be processed is produced using, for example, a micro sampling method. In the microsampling method, an analysis part including an observation part in an integrated circuit chip or a semiconductor wafer is supported by a probe (not shown), and an ion beam is irradiated from two directions having different angles with respect to the surface of the chip or the wafer. This technique separates and extracts the analysis part.

  First, as shown in FIG. 7A, the processing target sample 7 is placed (fixed) on the sample stage 41. The sample 7 to be processed extracted by the microsampling method is fixed to the probe, and the structure portion 71 on which the circuit pattern or the like is formed is on the upper side, and the non-structure portion 72 such as a silicon substrate portion on which the circuit pattern or the like is not formed. Located on the lower side. Before placing (fixing) the processing target sample 7 extracted by the microsampling method on the sample stage 41, the sample stage 41 is rotationally driven by the first sample rotation mechanism 42 to bring the placement surface into a vertical state. . Then, the sample 7 to be processed is brought into contact with the mounting surface of the sample table 41, and the sample 7 to be processed is fixed to the sample table 41 by an appropriate method (for example, tungsten deposition method). Thereafter, the processing sample 7 and the probe coupling portion (supporting portion) are separated by a focused ion beam (FIB) or the like.

  Next, from the state shown in FIG. 7A, the sample stage 41 is driven to rotate 180 ° by the second sample rotating mechanism 43, and as shown in FIG. The part is positioned above 72. In this state, the processing target sample 7 is processed by irradiating the processing target sample 7 with the focused ion beam (FIB) from the ion beam column 2. In this way, the FIB is irradiated from the non-structure part 72 side of the sample 7 to be processed, and the side surface including the interface between the structure part 71 and the non-structure part 72 is processed in a direction substantially perpendicular to the mounting surface of the sample stage 41. Thus, an observation target surface (surface along the paper surface in FIG. 7) for observing the structure of the sample 7 to be processed is formed. The distance (sample film thickness) between the two observation target surfaces of the processing target sample 7 is arbitrarily set by controlling the processing position with respect to the processing target sample 7 by controlling the deflection coil 23 of the ion beam column 2. Can do.

  Next, from the state shown in FIG. 7B, the sample stage 41 is rotated 90 ° by the first sample rotation mechanism 42 so that the mounting surface of the sample stage 41 is perpendicular to the optical axis of the ion beam. As shown in FIG. 7C, the observation target surface of the sample 7 to be processed and the interface between the structure portion 71 and the non-structure portion 72 are directed in the direction along the optical axis of the ion beam. In this state, a TEM image is acquired by irradiating with an ion beam, and the position of the interface between the structure portion 71 and the non-structure portion 72 is confirmed. Further, the SIM image is obtained by irradiating the electron beam of the electron beam column 3 from the observation target surface side of the processing target sample 7, and the interface between the structure portion 71 and the non-structure portion 72 of the processing target sample 7 is obtained from this SIM image. The deviation between the direction and the direction of the optical axis of the ion beam (angle information) is measured, and the deflection coil 23 of the ion beam column 2 is controlled based on the angle information, so that the interface between the structural portion 71 and the non-structural portion 72 Control is made so as to be directed along the optical axis of the ion beam (see FIG. 7D). In this state, the processing target sample 7 is processed by irradiating the processing target sample 7 with the focused ion beam (FIB) from the ion beam column 2. When the observation site is a portion where the source 12 and the drain 13 are formed in the transistor shown in FIG. 2, the vicinity of the boundary surface between the structure portion 71 and the non-structure portion 72 is the observation site. The FIB is irradiated from the direction along the observation surface of the sample 7 to be processed, and processed in a direction substantially parallel to the interface (observation part) between the structure part 71 and the non-structure part 72 to form a vacuum region near the observation part. Then, an observation sample used for observation by electron beam holography is prepared. The distance from the observation site (the interface between the structure portion 71 and the non-structure portion 72) to the vacuum region is arbitrarily set by controlling the deflection coil 23 of the ion beam column 2 and controlling the processing position with respect to the processing target sample 7. can do.

  The effects of the present embodiment configured as described above will be described in comparison with the prior art.

  In the semiconductor field, for example, the structure of the source and drain in a transistor is such that only an amount of ions of 10 ^ 21 / cm ^ 3 or less is implanted into silicon. Visualization is difficult with elemental analysis techniques such as EDX (Energy dispersive X-ray spectroscopy) and EESL (Electron Energy Loss Spectroscopy). On the other hand, the electron beam holography method makes it possible to visualize the sample structure by observing the interference image between the electron beam that has passed through the sample and the electron beam that has passed through the vacuum, and calculating the slight phase shift. it can. In an observation sample to which such an electron beam holography method is applied, thickness uniformity is very important, and a region without a substance (vacuum region) in the vicinity of the observation site is necessary.

  FIG. 8 is a diagram showing how an observation sample is produced in the prior art. In FIG. 8, the upward direction corresponds to the direction of the ion beam column 2 as in FIG.

  In FIG. 8, the sample stage 410 has its sample placement surface arranged perpendicular to the optical axis of the ion beam, and the sample 7 to be processed has its non-structured part 71 side on the placement surface of the sample stage 410. It is fixed. In this state, a focused ion beam (FIB) is irradiated from the ion beam column 2 to the sample 7 to be processed, thereby processing the side surface including the interface between the structure portion 71 and the non-structure portion 72, and the structure of the sample 7 to be processed. An observation target surface for observing the image is formed.

  Such a conventional technique does not have a mechanism for changing the direction of the sample 7 to be processed with respect to the ion beam, and forms the observation target surface by irradiation of the ion beam from the structure portion 71 side of the sample 7 to be processed. Therefore, there is a possibility that sample thickness unevenness (sample thickness variation) due to the sample structure may occur. Further, since there is no mechanism for changing the direction of the sample 7 to be processed, it is difficult to irradiate the ion beam from the direction along the interface between the structural part 71 and the non-structural part 72, and a desired distance from the observation site. It is difficult to form a vacuum region.

  On the other hand, in the present embodiment, the direction of the sample 7 to be processed with respect to the ion beam can be changed by the sample rotating mechanisms 42 and 43, so that the ion beam irradiation from the non-structure part 72 side of the sample 7 to be processed is performed. By forming an observation target surface, it is possible to suppress sample thickness unevenness due to the sample structure, and to form a vacuum region at a desired distance from the observation site, so that the thickness uniformity is high, and An observation sample having a vacuum region at a desired distance from the observation site can be produced.

  In the procedure shown in FIG. 7A and FIG. 7B, the sample stage 41 is rotated by 180 ° by the second sample rotation mechanism 43. However, the present invention is not limited to this. The structure may be rotated 180 ° by the rotation mechanism 42 so that the structure portion 71 is positioned on the lower side and the non-structure portion is positioned on the upper side of 72.

  In the procedure shown in FIG. 7D, the FIB irradiation angle with respect to the sample 7 to be processed is adjusted by controlling the deflection coil 22, but the present invention is not limited to this, and the sample stage 41 is moved to the first sample rotating mechanism 42. May be rotated to adjust the irradiation angle of the FIB with respect to the sample 7 to be processed.

  Furthermore, in the microsampling method, the analysis part is supported by the probe, but the present invention is not limited to this, and the analysis part may be supported by a microfork or microtweezers.

  Further, secondary electrons generated from the sample to be processed by the electron beam are detected by the secondary electron detector 5, and an SEM image is obtained from the control information of the deflection coil 33 and the detection information from the secondary electron detector 5, and displayed. However, the present invention is not limited to this. A transmission electron detector is provided on the opposite side of the electron beam column 3 across the sample 7 to be processed, and a TEM (Transmission Electron Microscope) image or STEM (Scanning Transmission Electron Microscope) is provided. It is good also as a structure which acquires an image.

It is a figure which shows the phase image when not using an observation sample in an electron beam holography method. It is a figure which shows typically the cross section of the observation sample to which an electron beam holography method is applied. It is a figure which shows typically the relationship between the phase image at the time of applying an electron beam holography method to an observation sample, and the structure of an observation sample. It is a figure which shows the phase image of the electron holography method in an observation sample. It is a figure which shows the image acquired by the normal TEM method in an observation sample. It is a figure which shows the whole structure of the sample preparation apparatus in this Embodiment. It is a figure which shows the procedure of observation sample preparation by the sample preparation apparatus of this Embodiment. It is a figure which shows observation sample preparation in a prior art.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Vacuum container 2 Charged particle beam column 3 Charged particle beam column 4 Sample stage 5 Secondary electron detector 6 Controller 11 Silicon substrate 12 Source 13 Drain 14 Insulating film 15 Gate 16 Contact plug 17 Silicon wiring 18 Interference fringe 21 Ion Gun 22 Lens 23 Deflection coil 31 Electron gun 32 Lens 33 Deflection coil 41 Sample stage 42 First sample rotation mechanism 43 Second sample rotation mechanism 61 Display device

Claims (7)

An observation sample preparation method in which an observation sample is prepared by processing a sample to be processed having at least two parts of a structure part in which a pattern is formed and a non-structure part in which a pattern is not formed with a charged particle beam,
A charged particle beam is irradiated from the unstructured part side of the sample to be processed, and a side surface including an interface between the structure part and the non-structured part is processed to form an observation target surface for observing the structure of the sample to be processed. Process,
And a step of processing the sample to be processed by irradiating the charged particle beam from a direction along the surface to be observed. An observation sample preparation method in which an observation sample is prepared by processing a sample to be processed having at least two parts of a structure part where a pattern is formed and a non-structure part where a pattern is not formed with a charged particle beam from a charged particle gun. There,
The charged sample is driven by rotating the sample to be processed around a first rotation axis perpendicular to the optical axis of the charged particle beam, with the non-structure portion side of the sample to be processed facing the charged particle gun side. Processing a side surface including an interface between the structure portion and the non-structure portion by a line to form an observation target surface for observing the structure of the processing target sample;
The sample to be processed is rotationally driven around a second rotation axis perpendicular to the first rotation axis, and the observation target surface is directed in a direction along the charged particle beam, and the processing is performed by the charged particle beam. And a step of processing the target sample. An observation sample preparation method in which an observation sample is prepared by processing a sample to be processed having at least two parts of a structure part in which a pattern is formed and a non-structure part in which a pattern is not formed with a charged particle beam,
A charged particle beam is irradiated from the unstructured part side of the sample to be processed, and a side surface including an interface between the structure part and the non-structured part is processed to form an observation target surface for observing the structure of the sample to be processed. Process,
Irradiating a charged particle beam from a direction along the observation target surface to detect secondary electrons generated from the processing target sample, and obtaining a charged particle beam image of the processing target sample based on the detection information;
And a step of processing the sample to be processed by irradiating the charged particle beam from a direction along the surface to be observed. An observation sample preparation method in which an observation sample is prepared by processing a sample to be processed having at least two parts of a structure part where a pattern is formed and a non-structure part where a pattern is not formed with a charged particle beam from a charged particle gun. There,
The charged sample is driven by rotating the sample to be processed around a first rotation axis perpendicular to the optical axis of the charged particle beam, with the non-structure portion side of the sample to be processed facing the charged particle gun side. Processing a side surface including an interface between the structure portion and the non-structure portion by a line to form an observation target surface for observing the structure of the processing target sample;
Irradiating a charged particle beam from a direction along the observation target surface to detect secondary electrons generated from the processing target sample, and obtaining a charged particle beam image of the processing target sample based on the detection information;
The sample to be processed is rotationally driven around a second rotation axis perpendicular to the first rotation axis, the observation target surface is directed in a direction along the charged particle beam, and the processing is performed by the charged particle beam. And a step of processing the target sample. An observation sample for producing an observation sample by processing a sample to be processed having at least two parts of a structure part where a pattern is formed and a non-structure part where a pattern is not formed with a charged particle beam from a first charged particle gun A production method comprising:
The sample to be processed is rotationally driven around a first rotation axis perpendicular to the optical axis of the charged particle beam, the non-structure part side of the sample to be processed is directed to the first charged particle gun side, Forming an observation target surface for observing the structure of the sample to be processed by processing a side surface including an interface between the structure portion and the non-structure portion with the charged particle beam;
By irradiating the sample to be processed with a charged particle beam from a second charged particle gun, secondary electrons generated from the sample to be processed are detected, and based on the detection information, a charged particle beam image of the sample to be processed is obtained. A process of acquiring;
Detecting a direction of the sample to be processed from the charged particle beam image, controlling a deflection coil of the first charged particle beam gun based on the direction, and adjusting a deflection angle;
The sample to be processed is rotationally driven around a second rotation axis perpendicular to the first rotation axis, the observation target surface is directed in a direction along the charged particle beam, and the processing is performed by the charged particle beam. And a step of processing the target sample. An observation sample preparation method in which an observation sample is prepared by processing a sample to be processed having at least two parts of a structure part where a pattern is formed and a non-structure part where a pattern is not formed with a charged particle beam from a charged particle gun. There,
Fixing a surface including an interface between the structure part and the non-structure part of the sample to be processed to a sample table for placing the sample to be processed;
The charged sample is driven by rotating the sample to be processed around a first rotation axis perpendicular to the optical axis of the charged particle beam, with the non-structure portion side of the sample to be processed facing the charged particle gun side. Processing a side surface including an interface between the structure portion and the non-structure portion by a line to form an observation target surface for observing the structure of the processing target sample;
The sample to be processed is rotationally driven around a second rotation axis perpendicular to the first rotation axis, the observation target surface is directed in a direction along the charged particle beam, and the processing is performed by the charged particle beam. And a step of processing the target sample. First charged particle beam irradiation means for irradiating a charged particle beam for processing a sample to be processed;
First sample rotating means for rotating the sample to be processed around a first rotation axis perpendicular to the optical axis of the charged particle beam;
Second sample rotating means for rotating the sample to be processed around a second rotation axis perpendicular to the first rotation axis;
A second charged particle beam irradiation means for acquiring a charged particle beam image of the sample to be processed;
Deflection angle adjusting means for controlling a deflection coil of the first charged particle beam irradiation means based on the direction of the sample to be processed detected from the charged particle beam image and adjusting a deflection angle. A featured observation sample preparation device.