Thin film sample preparation method and charged particle beam device

Abstract

Provided are a method for preparing a thin film sample and a charged particle beam device, which can suppress the defects of the thin film sample. The method comprises the following steps: processing the sample (S) by irradiating a convergent ion beam (FIB2) from a second direction intersecting the normal direction (z) of the surface of the sample (S) to prepare a thin film sample (1), and preparing a connecting portion (3) arranged on one side of the thickness direction (x) of the thin film sample (1) of the sample (S) and connecting the thin film sample (1) to the sample (S); rotating the sample (S) around the normal direction (z); connecting a probe for holding the thin film sample (1) to the thin film sample (1); and irradiating the connecting portion (3) with a convergent ion beam (FIB3) from a third direction intersecting the normal direction (z) to separate the thin film sample (1) from the sample (S).

Description

Technical Field

[0001] The invention relates to a thin film sample piece manufacturing method and a charged particle beam device. Background Art

[0002] Conventionally, there is a known technique for observing the microscopic cross-sectional structure of semiconductor devices and semiconductor elements (e.g., DRAM elements, nonvolatile memories, or solid-state imaging elements) using a transmission electron microscope (TEM) to perform failure analysis. Generally, when observing using a transmission electron microscope, it is necessary to take out a microscopic thin film sample from a sample as an observation object and then fix the thin film sample to a sample holder to prepare a TEM sample (e.g., see Patent Documents 1 and 2).

[0003] Here, a general method for preparing a TEM sample is briefly described.

[0004] First, the sample is irradiated with a focused ion beam (FIB), which is a type of charged particle beam, and etched to produce a thin film sample with a thickness of tens to hundreds of nm. At this time, the thin film sample is not completely cut off from the sample, but is produced in a state where it is partially connected to the sample via a connecting portion. Next, the thin film sample is held by a probe or a nano-tweezer. When a probe is used, the FIB is irradiated while supplying a raw material gas for producing a deposited film near the end of the probe. In this way, the secondary electrons generated by irradiating the FIB decompose the raw material gas, so that the deposited film is deposited at the boundary between the probe and the thin film sample. As a result, the thin film sample can be fixed to the end of the probe and held.

[0005] After the probe is held to the thin film sample, the FIB is irradiated to the connecting portion to carry out etching.Thus, the connecting portion can be cut off, so that the thin film sample can be completely cut off from the sample.Next, while utilizing the probe or nano-tweezers to hold the thin film sample, the thin film sample is separated from the sample.Then, by moving the stage, the sample holder is moved to the vicinity of the directly below the thin film sample, so that the thin film sample is close to the upper surface or the side of the sample holder.Next, while supplying raw gas to the boundary of the thin film sample and the sample holder once again, while irradiating FIB.Thus, the deposited film can be deposited between the thin film sample and the sample holder, so that the thin film sample can be fixed to the sample holder.

[0006] Patent Document 1: Japanese Patent Application Publication No. 2016-050853

[0007] Patent Document 2: Japanese Patent Application Publication No. 2009-110745

[0008] When the thin film sample piece is separated from the sample by irradiating the connecting portion with FIB, a part of the thin film sample piece may be damaged. Summary of the invention

[0009] An object of the present invention is to provide a thin film sample production method and a charged particle beam device capable of suppressing the thin film sample from being damaged.

[0010] In order to solve the above-mentioned problems, the present invention is a method for preparing a thin film sample piece, which uses the sample to prepare a thin film sample piece whose thickness direction is along the surface of the sample, wherein the thin film sample piece preparation method includes the following steps: processing the sample by irradiating a charged particle beam from a first direction which is a normal direction of the surface of the sample and a second direction intersecting the normal direction to prepare the thin film sample piece, and preparing a connecting portion which is arranged on one side in the thickness direction of the thin film sample piece and connects the thin film sample piece to the sample; a step of rotating the sample around the normal direction; a step of connecting a holding component that holds the thin film sample piece to the thin film sample piece; and a step of irradiating a charged particle beam from a third direction intersecting the normal direction to the connecting portion to separate the thin film sample piece from the sample.

[0011] The present invention is a charged particle beam device, which uses the sample to produce a thin film sample piece along the surface of the sample in the thickness direction, wherein the charged particle beam device has: a charged particle beam irradiation optical system, which irradiates the charged particle beam along the direction intersecting the vertical direction; a carrier, which carries the sample and moves; a holding component, which holds the thin film sample piece separated and taken out from the sample; and a control unit, which controls the actions of the charged particle beam irradiation optical system, the carrier and the holding component, the control unit processes the sample by irradiating the charged particle beam from a first direction which is the normal direction of the surface of the sample and a second direction intersecting the normal direction, thereby producing the thin film sample piece, and producing a connecting portion which is arranged on one side in the thickness direction of the thin film sample piece and connects the thin film sample piece to the sample, rotates the carrier around the normal direction, connects the holding component to the thin film sample piece, irradiates the charged particle beam to the connecting portion from a third direction intersecting the normal direction, and separates the thin film sample piece from the sample.

[0012] The control unit irradiates the charged particle beam from the second direction intersecting the normal direction to produce the thin film sample and the connecting portion. After the control unit rotates the sample so that the holding component is connected to the thin film sample, the charged particle beam is irradiated from the third direction intersecting the normal direction to remove the connecting portion. In the present invention, a connecting portion is configured on one side of the thickness direction of the thin film sample. Thus, even when the charged particle beam is irradiated from the third direction, the charged particle beam can only be irradiated to the connecting portion. Therefore, the defect of the thin film sample is suppressed.

[0013] The control unit irradiates the connection portion with a charged particle beam from the third direction, and performs surface processing on an end surface in a thickness direction of the thin film sample where the connection portion is arranged.

[0014] Thus, the structure contained in the thin film sample piece can be visually recognized and the target position of the cross-sectional observation can be identified. After the thin film sample piece is separated from the sample, it is not necessary to perform surface processing such as cleaning again. Therefore, the production time of the thin film sample piece is shortened.

[0015] When a side of both sides in the thickness direction of the film sample piece on which the connecting portion is to be formed is input, the control unit causes the connecting portion to be formed on the input side.

[0016] Thus, a connecting portion is made on one side of the expectation of the film coupon. Especially, when the charged particle beam is irradiated to the connecting portion and the surface processing of the end face is carried out simultaneously, the structure included in the film coupon can be visually recognized from the end face. Therefore, by making a connecting portion on the end face where the cross-section observation is desired, the target position of the cross-section observation is determined.

[0017] The third direction is a direction parallel to the end surface of the thin film sample piece in the thickness direction.

[0018] In this case, the charged particle beam can be irradiated only to the connection portion, thereby suppressing the thin film sample from being damaged. In particular, when the surface of the end face is processed while the charged particle beam is irradiated to the connection portion, the end face can be processed with high precision.

[0019] The thin film sample preparation method and charged particle beam device of the present invention configure the connecting portion that connects the thin film sample to the sample on one side in the thickness direction of the thin film sample. Thus, even when the charged particle beam is irradiated from the third direction, the charged particle beam can be irradiated only to the connecting portion. Therefore, the defect of the thin film sample is suppressed. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a schematic configuration diagram of a charged particle beam device according to an embodiment.

[0021] Figure 2 It is a flowchart of the thin film sample preparation method according to the embodiment.

[0022] Figure 3 This is a first explanatory diagram of the thin film sample preparation method according to the embodiment.

[0023] Figure 4 This is a second explanatory diagram of the thin film sample preparation method according to the embodiment.

[0024] Figure 5 This is a third explanatory diagram of the thin film sample preparation method according to the embodiment.

[0025] Figure 6 yes Figure 5 A cross-sectional view taken along line VI-VI.

[0026] Figure 7 This is a fourth explanatory diagram of the thin film sample preparation method according to the embodiment.

[0027] Figure 8 yes Figure 7 A cross-sectional view taken along line VIII-VIII.

[0028] Fig. 9 It is an explanatory diagram of a method for preparing a thin film sample piece of a comparative example.

[0029] Fig.10 yes Fig. 9 Cross-sectional view of line XX.

[0030] Fig.11 It is an explanatory diagram of a thin film sample preparation method according to a first modified example of the embodiment.

[0031] Fig.12 yes Fig.11 A cross-sectional view taken along line XII-XII.

[0032] Description of symbols

[0033] FIB, FIB1, FIB2, FIB3: converged ion beam (charged particle beam); N: probe (holding component); S: sample; x: thickness direction; z: normal direction; 1: thin film sample piece; 3: connecting part; 10: charged particle beam device; 11: carrier; 16: control part; 32: FIB irradiation optical system (charged particle beam irradiation optical system). DETAILED DESCRIPTION

[0034] Hereinafter, a charged particle beam device and a thin film sample production method according to an embodiment will be described with reference to the drawings.

[0035] (Charged particle beam device)

[0036] Figure 11 is a schematic structural diagram of a charged particle beam device according to an embodiment. The charged particle beam device 10 according to the embodiment can automatically produce a thin film sample piece 1 using a sample S. The charged particle beam device 10 has: a stage 11 on which a sample S is placed; an irradiation mechanism 12 that irradiates a converged ion beam (FIB) and an electron beam (EB); a detector 13 that detects secondary charged particles E generated by irradiating the FIB or EB; a gas gun 14 that provides a raw material gas G for forming a deposited film D; a control unit 16 that generates image data based on the detected secondary charged particles E and displays the image data on a display unit 15; and a probe (holding component) N that can hold the thin film sample piece 1.

[0037] The sample S is placed on the stage 11 in a state of being fixed to the holder 20 .

[0038] The stage 11 moves according to the instruction of the control unit 16 and can be displaced in five axes. That is, the stage 11 is supported by a displacement mechanism 30, which includes: a linear movement mechanism 30a that moves the holder 20 along the X-axis and Y-axis that are parallel to the horizontal plane and perpendicular to each other, and a Z-axis that is perpendicular to the X-axis and the Y-axis; a tilting mechanism 30b that tilts the holder 20 while rotating around the X-axis (or the Y-axis); and a rotating mechanism 30c that rotates the holder 20 around the Z-axis.

[0039] Thus, the displacement mechanism 30 displaces the stage 11 along the five axes, so that the FIB or EB can be irradiated toward a desired position. In addition, the stage 11 and the displacement mechanism 30 are accommodated in the vacuum chamber 31. Therefore, the irradiation of the FIB or EB, the supply of the raw material gas G, etc. are performed in the vacuum chamber 31.

[0040] The irradiation mechanism 12 includes: a FIB irradiation optical system (charged particle beam irradiation optical system) 32, which is arranged above the stage 11 and irradiates the FIB in a direction intersecting the Z axis (vertical direction); and a SEM optical system 33, which irradiates the EB in a vertical direction parallel to the Z axis. The optical axis direction of the FIB irradiation optical system 32 intersects with the vertical direction. The optical axis direction of the FIB irradiation optical system 32 intersects with the normal direction of the upper surface of the stage 11 configured in a standard state. The standard state of the stage 11 refers to a state in which at least the tilt mechanism 30b in the displacement mechanism 30 is configured at the origin. The optical axis direction of the FIB irradiation optical system 32 intersects with the central axis C of the vacuum chamber 31. On the other hand, the optical axis direction of the SEM optical system 33 coincides with the central axis C of the vacuum chamber 31. The electric field inside the vacuum chamber 31 is formed to be roughly axisymmetric about the central axis C. Therefore, the observation accuracy of the SEM optical system 33 is improved.

[0041] The FIB irradiation optical system 32 includes an ion generating source 32a and an ion optical system 32b, and ions generated by the ion generating source 32a are made into a relatively fine FIB by the ion optical system 32b, and then irradiated toward the sample S or the sample holder. In addition, the SEM optical system 33 includes an electron generating source 33a and an electron optical system 33b, and electrons generated by the electron generating source 33a are made into a relatively fine EB by the electron optical system 33b, and then irradiated toward the sample S or the sample holder.

[0042] During FIB or EB irradiation, the detector 13 detects secondary charged particles E such as secondary electrons or secondary ions emitted from the sample S or the sample holder, and outputs them to the control unit 16. The gas gun 14 supplies a compound gas containing a material (such as phenanthrene, platinum, carbon or tungsten) as a raw material gas G as a raw material gas. The raw material gas G is decomposed by the secondary charged particles E generated by FIB irradiation and separated into a gas component and a solid component. Then, the solid component of the two separated components is deposited to form a deposited film D.

[0043] The holding mechanism 17 includes a probe moving mechanism 17a, the base end of which is mounted on the vacuum chamber 31, and a probe N, which is moved by the probe moving mechanism 17a. The probe N can be moved horizontally and vertically by the probe moving mechanism 17a, and can also be rotated around the central axis of the probe N. Thus, the thin film sample piece 1 held by the probe N can be freely moved in a held state.

[0044] The control unit 16 can uniformly control the structural components of the charged particle beam device 10, and can change the acceleration voltage or beam current of the FIB irradiation optical system 32 and the SEM optical system 33. In particular, the control unit 16 can freely adjust the beam diameter of the FIB by changing the acceleration voltage or beam amount of the FIB irradiation optical system 32. Thus, not only can the observation image be obtained, but also the sample S can be locally etched. Moreover, when etching, by adjusting the beam diameter, the processing accuracy can be freely changed from rough processing to fine processing.

[0045] In addition, after the control unit 16 converts the secondary charged particles E detected by the detector 13 through the irradiation of FIB or EB into a brightness signal and generates observation image data, it outputs the observation image to the display unit 15 according to the observation image data. Thus, the display unit 15 can display the observation image. In addition, the control unit 16 is connected to an input unit 16a for the operator to input, and each component is controlled according to the signal input by the input unit 16a. That is, the operator can irradiate the FIB or EB to the desired area through the input unit 16a and observe it, can irradiate the FIB to the desired area for etching processing, or can irradiate the FIB while supplying the raw material gas G to the desired area to deposit the deposited film D.

[0046] (Thin film sample preparation method)

[0047] A method for preparing a thin film specimen using the charged particle beam device 10 according to the embodiment will be described.

[0048] Figure 2 It is a flowchart of the thin film sample preparation method according to the embodiment. Figure 3 1 is a first explanatory diagram of a method for preparing a thin film sample piece according to an embodiment of the present invention. Figure 4 2 is the second explanatory diagram. In the present application, the x-direction, y-direction and z-direction of the rectangular coordinate system are defined as follows. The z-direction is the normal direction of the surface of the sample S. The +z-direction is the direction away from the surface of the sample S along the normal direction toward the outside of the sample S. The x-direction is the thickness direction of the film sample piece 1. The y-direction is the width direction of the film sample piece 1 perpendicular to the z-direction and the x-direction.

[0049] The thin film sample piece 1 is used to observe the cross section of a structure such as a semiconductor element included in the sample S. Figure 4 As shown, a thin film sample piece 1 is extracted from the surface of the sample S. The thin film sample piece 1 is formed with a predetermined thickness in the x direction along the surface of the sample S. The thin film sample piece 1 is formed with a predetermined width in the y direction along the surface of the sample S. The thin film sample piece 1 is formed with a predetermined depth (height) from the surface of the sample S in the -z direction.

[0050] The operator inputs the production area of ​​the thin film sample piece 1 from the input unit 16a (S10). For example, the operator inputs the center point of the production area S1 of the thin film sample piece 1 on the surface of the sample S. The operator inputs the dimensions of the sample S in the x-direction, the y-direction, and the z-direction. Figure 3 As shown, the production area S1 of the thin film sample piece 1 is set. The set production area S1 of the thin film sample piece 1 and the image of the surface of the sample S are overlapped and displayed on the display unit 15.

[0051] The control unit 16 sets the processing area S2 of the sample S corresponding to the production area S1 of the thin film sample piece 1 (S12). Figure 4 As shown, the thin film sample piece 1 is separated from the sample S, and a gap 2 is formed in the ±y direction and the -z direction of the thin film sample piece 1. In order to form the gap 2, an inclined surface 5 is formed in the ±x direction of the thin film sample piece 1. The inclined surface 5 is formed in such a way that a position on the surface of the sample S away from the thin film sample piece 1 in the ±x direction is connected to a position in the -z direction of the thin film sample piece 1. The inclined surface 5 is formed to be wider than the width of the thin film sample piece 1 in the y direction. For example, the inclination angle of the inclined surface 5 relative to the z direction is the same as the inclination angle of the optical axis direction of the FIB irradiation optical system 32 relative to the vertical direction. As shown in FIG. Figure 3 As shown, the control unit 16 sets the production area of ​​the inclined surface 5 as the processing area S2 of the sample S. The display unit 15 overlaps the set processing area S2 of the sample S with the image of the surface of the sample S and displays them.

[0052] The control unit 16 sets the production area S3 of the connection unit 3. Figure 4 As shown, the connecting portion 3 connects the sample S with the film sample piece 1 before the film sample piece 1 is separated from the sample S. As described later, the connecting portion 3 connects the sample S with the film sample piece 1 when the probe N is connected to the film sample piece 1. The connecting portion 3 is formed as a part across the gap 2. The connecting portion 3 is formed at the corner of the y direction and the z direction of the film sample piece 1. Below, the situation that the connecting portion 3 is formed at the corner of the -y direction and the +z direction of the film sample piece 1 is described as an example. The size (thickness in the x direction, length in the y direction, height in the z direction) of the connecting portion 3 is preset to a specified size.

[0053] The connecting portion 3 is formed on the +x side or -x side of the thin film sample piece 1. Figure 3 As shown, the production area S3 of the connecting portion 3 is set adjacent to the production area S1 of the film sample piece 1 in the x direction.

[0054] The control unit 16 receives the input of one side of the two sides S18 and S19 in the x direction of the film sample piece 1 for making the connecting portion 3. For example, the control unit 16 displays information on the display unit 15, urging the operator to input the side of the connecting portion 3. The operator uses the input unit 16a to input the side of the connecting portion 3. As described later, with the removal of the connecting portion 3, the end face in the x direction of the side forming the connecting portion 3 of the film sample piece 1 is cleaned. Therefore, the operator inputs one side of the end face to be observed in cross section of the two end faces in the x direction of the film sample piece 1 as the side of the connecting portion 3.

[0055] The control unit 16 determines whether a side for making the connecting portion 3 is input (S14). When the judgment of S14 is "yes", the control unit 16 sets the making area S3 of the connecting portion 3 on the input side (S16). When the judgment of S14 is "no", the control unit 16 sets the making area S3 of the connecting portion 3 on the pre-registered standard side (S18). For example, the pre-registered standard side is the opposite side of the side connected to the probe N on both sides in the x direction of the thin film sample piece 1. Thus, when the connecting portion 3 is irradiated with FIB and the connecting portion 3 is removed, the irradiation of FIB to the probe N can be suppressed. The display unit 15 displays the image of the setting making area S3 of the connecting portion 3 and the surface of the sample S. Below, the case of making the connecting portion 3 on the +x side S18 of the thin film sample piece 1 is described as an example.

[0056] The control unit 16 controls the FIB irradiation optical system 32 to process the sample S ( S20 ).

[0057] The specific processing sequence is as follows. Figure 4 As shown, the control unit 16 drives the displacement mechanism 30 of the stage 11 so that the normal direction (z direction) of the sample S is consistent with the optical axis direction of the FIB irradiation optical system. The control unit 16 irradiates FIB1 along the z direction (first direction). The control unit 16 irradiates FIB1 to the processing area S2 of the sample S except the production area S1 of the thin film sample piece 1 and the production area S3 of the connecting part 3. The processing depth from the surface of the sample S to the -z direction is adjusted by the intensity or irradiation time of FIB1. Thus, the thin film sample piece 1 is formed into a specified thickness, and an inclined surface 5 is formed in the ±x direction of the thin film sample piece 1.

[0058] The control unit 16 drives the displacement mechanism 30 of the stage 11 to move the stage 11 to a standard state. As a result, the normal direction (z direction) of the sample S is consistent with the vertical direction and intersects with the optical axis direction of the FIB irradiation optical system 32. The control unit 16 irradiates FIB2 from a second direction intersecting with the z direction. The control unit 16 irradiates FIB2 around the thin film sample piece 1 except for the manufacturing part of the connecting part 3. As a result, the outer shape of the thin film sample piece 1 is formed, and the gap 2 is formed around the thin film sample piece 1.

[0059] The control unit 16 drives the rotation mechanism 30c of the displacement mechanism 30 of the stage 11 to rotate the stage 11 on which the sample S is placed (S22). The control unit 16 rotates the stage 11 around the vertical direction while keeping the stage 11 in the standard state. The control unit 16 rotates the sample S around the normal direction z. The control unit 16 rotates the stage 11 90°. Thus, the FIB irradiation optical system 32 irradiates FIB3 to the sample S from the third direction intersecting the z direction. The third direction as the irradiation direction of FIB3 is different from the second direction as the irradiation direction of FIB2, and is a direction parallel to the end face of the thin film sample piece 1 in the x direction.

[0060] The reason for rotating the stage 11 is as follows. After the control unit 16 forms the thin film sample piece 1 by irradiating FIB2 from the second direction, the probe N is connected to the thin film sample piece 1 as described later, and the thin film sample piece 1 is separated from the sample S. In addition, the control unit 16 moves the probe N, and the thin film sample piece 1 is fixed to the sample holder with a prescribed attitude. If the stage 11 is rotated in advance before the probe N is connected to the thin film sample piece 1, after separating the thin film sample piece 1, the movement of the probe N can become simple. That is, only by the rotation movement and linear movement around the central axis of the probe N, the thin film sample piece 1 can be fixed to the sample holder with a prescribed attitude.

[0061] Figure 5 This is a third explanatory diagram of the thin film sample piece manufacturing method according to the embodiment, and is a plan view of the sample S. Figure 6 yes Figure 5 Side cross-sectional view along line VI-VI. The control unit 16 connects the probe N to the thin film sample piece 1 (S24). The end of the probe N is perpendicular to the y direction, and approaches the thin film sample piece 1 in a state facing the +x direction and -z direction. The end of the probe N approaches the corners in the +y direction and +z direction on the end face in the -x direction of the thin film sample piece 1. The control unit 16 supplies the raw material gas G of the deposited film from the gas gun 14 toward the end of the probe N. The control unit 16 irradiates the FIB3 toward the end of the probe N. As a result, a deposited film is formed between the end of the probe N and the thin film sample piece 1, and the end of the probe N is connected to the thin film sample piece 1.

[0062] Figure 7 This is a fourth explanatory diagram of the thin film sample piece manufacturing method according to the embodiment, and is a plan view of the sample S. Figure 8 yes Figure 7 The control unit 16 irradiates FIB3 to the connecting portion 3, removes (cuts off) the connecting portion 3, and separates the thin film sample piece 1 from the sample S (S26). The specific sequence is as follows. The control unit 16 sets the irradiation frame FL of FIB3. Figure 8As shown in FIG. 1 , when viewed from the x direction, the irradiation frame FL is set to a rectangular shape extending parallel to the irradiation direction of FIB 3. The irradiation frame FL is set to a size that at least includes the overlapping area A3 of the film sample piece 1 and the connecting portion 3 when viewed from the x direction. Figure 7 As shown in FIG. 1 , the irradiation frame FL is set to a size that includes the entire thickness of the connecting portion 3 in the x direction when viewed from the z direction.

[0063] The control unit 16 irradiates FIB3 within the range of the irradiation frame FL. When the connection portion 3 of the overlapping area A3 is removed by utilizing the irradiation of FIB3, the thin film sample piece 1 is separated from the sample S. As mentioned above, FIB3 is irradiated in a manner parallel to the end face in the x direction of the thin film sample piece 1. The connection portion 3 and the thin film sample piece 1 are adjacently configured in the +x direction. Therefore, it is possible to avoid the thin film sample piece 1 and only irradiate FIB3 to the connection portion 3. Thus, the defect of the thin film sample piece 1 is suppressed.

[0064] The control unit 16 drives the linear motion mechanism 30a of the displacement mechanism 30 of the stage 11, so that the stage 11 moves vertically downward (S28). Thus, the sample S placed on the stage 11 is separated from the thin film sample piece 1 held by the probe N. The control unit 16 drives the probe moving mechanism 17a to move the probe (S30). The control unit 16 rotates the probe N around the central axis. Thus, the thin film sample piece 1 is changed into a prescribed posture. The control unit 16 moves the probe N linearly toward the sample holder. The control unit 16 fixes the thin film sample piece 1 of the prescribed posture to the sample holder (S32). Above, the processing of the thin film sample piece manufacturing method ends.

[0065] Fig. 9 It is an explanatory diagram of a method for preparing a thin film sample piece according to a comparative example and is a top view of a sample S. Fig.10 yes Fig. 9 The side cross-sectional view of the XX line. Fig. 9 As shown in FIG. 1 , the connecting portion 93 of the comparative example is formed at the same position in the x direction as the thin film sample piece 1. The connecting portion 93 is formed in the -y direction of the thin film sample piece 1. Fig.10 As shown, the control unit 16 irradiates FIB3 to the irradiation frame FL, removes the connecting portion 93, and separates the thin film sample piece 1 from the sample S. As described above, FIB3 is irradiated in a manner parallel to the end surface in the x direction of the thin film sample piece 1. Therefore, a part of FIB3 will irradiate the thin film sample piece 1 before reaching the connecting portion 3. As a result, a defect 99 of the thin film sample piece 1 is generated.

[0066] In contrast, in the charged particle beam apparatus and the thin film sample fabrication method of the present embodiment, Figure 7As shown, the connection portion 3 is formed on one side in the x direction of the film sample piece 1. Therefore, when the FIB 3 is irradiated from the third direction, the FIB 3 can be irradiated only to the connection portion 3. Therefore, the film sample piece 1 is prevented from being damaged.

[0067] (Variation Example)

[0068] Fig.11 It is an explanatory diagram of a method for preparing a thin film sample piece according to a modified example of the embodiment, and is a plan view of a sample S. Fig.12 yes Fig.11 The control unit 16 of the modified example irradiates the connection portion 3 with the FIB 3 and performs surface processing on the end surface of the thin film specimen 1 in the x direction ( S26 ).

[0069] The specific sequence is as follows. The control unit 16 sets the irradiation frame FL of FIB3. Fig.12 As shown in FIG. 1 , the irradiation frame FL is set to a size that includes at least the entire area A1 of the end surface of the film sample piece 1 in the x direction when viewed from the x direction. The entire area A1 of the film sample piece 1 includes the overlapping area A3 of the film sample piece 1 and the connecting portion 3. Fig.11 As shown, the irradiation frame FL is set to a size that includes the entire thickness of the connecting portion 3 in the x direction and the end surface of the film sample piece 1 in the +x direction when viewed from the z direction.

[0070] The control unit 16 irradiates FIB3 within the range of the irradiation frame FL. When the connecting portion 3 of the overlapping area A3 is removed by irradiating FIB3, the thin film sample piece 1 is separated from the sample S. FIB3 is also irradiated to the end face in the +x direction of the thin film sample piece 1. Thus, the end face in the +x direction of the thin film sample piece 1 is cleaned. During the processing of the aforementioned sample S, processing chips and the like are attached to the end face in the +x direction of the thin film sample piece 1. The attachments on the end face are removed by cleaning processing. Through the end face processing, the structure contained in the thin film sample piece 1 can be visually recognized, and the target position of the cross-sectional observation can be determined.

[0071] As described in detail above, in the charged particle beam device and the thin film sample preparation method of the modified example, the control unit 16 irradiates the FIB 3 to the connecting portion 3, and performs surface processing on the end face of the thin film sample 1 in the x direction where the connecting portion 3 is arranged. Thus, after the thin film sample 1 is separated from the sample S, it is not necessary to perform surface processing such as cleaning again. Therefore, the preparation time of the thin film sample 1 is shortened.

[0072] In the above-described embodiment, when the control unit 16 receives an input of one side of the film sample piece 1 in the x direction on which the connecting portion 3 is to be formed, the control unit 16 forms the connecting portion 3 on the input side.

[0073] Thus, the connecting portion 3 is made on the desired side of the film sample piece 1. In particular, when the surface processing of the end face is performed as in the modified example, the structure contained in the film sample piece 1 can be visually recognized from the end face. Therefore, the end face side where the cross-section observation is desired is input as the side where the connecting portion 3 should be made. Thus, the end face on the manufacturing side of the connecting portion 3 is surface processed, and the target position of the cross-section observation is identified.

[0074] In the above-mentioned embodiment, the third direction as the irradiation direction of the FIB 3 is a direction parallel to the end surface of the thin film sample piece 1 in the x direction.

[0075] In this case, FIB3 can be irradiated only to the connection portion 3, thereby suppressing the damage of the thin film coupon 1. In particular, when the surface processing of the end face is performed as in the modification, FIB3 is uniformly irradiated to the entire area A1 of the end face, so that the end face processing can be performed uniformly and accurately.

[0076] As mentioned above, one embodiment of the present invention has been described in detail with reference to the drawings, but the specific structure is not limited to this embodiment, and changes, combinations, deletions, etc. of the structure are also included without departing from the scope of the gist of the present invention.

Claims

1. A method for preparing a thin film sample piece, using a sample to prepare a thin film sample piece whose thickness direction is along the surface of the sample, in, The film sample preparation method comprises the following steps: The sample is processed by irradiating a charged particle beam from a first direction, which is a normal direction of a surface of the sample, and from a second direction intersecting the normal direction, to produce the thin film sample piece, and to produce a connecting portion which is arranged on one side in a thickness direction of the thin film sample piece and extends from the thin film sample piece to the sample to connect the thin film sample piece and the sample; Rotating the sample around the normal direction; connecting a holding member for holding the thin film sample piece to the thin film sample piece; and The thin film sample piece is separated from the sample by irradiating the connection portion with a charged particle beam from a third direction, wherein the third direction is a direction intersecting the normal direction and parallel to an end surface of the thin film sample piece in a thickness direction.

2. A charged particle beam device, which uses a sample to produce a thin film sample piece with a thickness direction along the surface of the sample, in, The charged particle beam device has: a charged particle beam irradiation optical system for irradiating the charged particle beam in a direction intersecting the vertical direction; A stage for carrying and moving the sample; a holding member that holds the thin film sample piece separated and taken out from the sample; and a control unit that controls the operations of the charged particle beam irradiation optical system, the stage, and the holding member, The control unit processes the sample by irradiating the sample with a charged particle beam from a first direction which is a normal direction of a surface of the sample and from a second direction which intersects the normal direction, thereby producing the thin film sample piece, and producing a connecting portion which is arranged on one side in a thickness direction of the thin film sample piece and extends from the thin film sample piece to the sample to connect the thin film sample piece and the sample, Rotate the stage around the normal direction, connecting the holding member to the film sample piece, The thin film sample piece is separated from the sample by irradiating the connection portion with a charged particle beam from a third direction, wherein the third direction is a direction intersecting the normal direction and parallel to an end surface of the thin film sample piece in a thickness direction.

3. The charged particle beam device according to claim 2, wherein: The control unit irradiates the connection portion with a charged particle beam from the third direction, and performs surface processing on an end surface in a thickness direction of the thin film sample where the connection portion is arranged.

4. The charged particle beam device according to claim 2 or 3, wherein: When receiving an input of a side on which the connecting portion is to be formed, out of both sides in the thickness direction of the film sample piece, the control unit causes the connecting portion to be formed on the input side.

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