JP6517532B2 - Charged particle beam device - Google Patents

Description

  The present invention relates to a charged particle beam apparatus for evaluating the torsional characteristics of a minute sample piece.

  Conventionally, using a focused ion beam (hereinafter referred to as FIB) or the like, observation with a scanning electron microscope (hereinafter referred to as SEM) or a transmission electron microscope (hereinafter referred to as TEM) or It is known to make sample pieces for performing analysis.

  There are various aspects of observation by SEM. For example, while applying tensile force to a sample piece, SEM observation of the sample piece is performed to detect a change in shape of crystal grains constituting the sample piece, and a method for accurately measuring local stress and strain is disclosed. (See Patent Document 1).

JP, 2008-191120, A

  With the recent spread of MEMS (micro-electro-mechanical systems) and 3D printers, while microstructures are being created, mechanical characteristics (properties such as tension, compression, torsion, bending, fatigue, etc.) evaluation of the created microstructures Is required. Although it is possible to evaluate sample pieces in mm (millimeter) units with existing evaluation equipment, for sample pieces less than mm units, that is, less than μm (micrometers), the evaluation equipment is also evaluated. It is also difficult and small to make a sample to be made.

  In general, the mechanical properties for a sample piece of several tens of mm do not match the mechanical properties of a sample piece of μm, and it is said that the characteristic features of the micro sample piece appear. For example, a square pillar of mm in silicon single crystal (for example, a square pillar of 5 mm × 5 mm × 100 mm) is extremely brittle and subjected to a so-called three-point bending test in which a vertical load is applied to both ends and the center. It breaks brittlely without bending. However, even if the single silicon single crystal is subjected to a three-point bending test on, for example, a minute square pole of 1 μm × 1 μm × 100 μm, the minute square pole exhibits a large bending elastic property.

  Thus, although μm-unit MEMS and microstructures are actively produced in recent years, it is a fact that mechanical evaluation of these microparts has not been sufficiently performed.

  The torsion evaluation of the micro sample piece in the present specification means not only the determination of the torsional rigidity value, but also the evaluation of the microscopic sample of the sample surface and the inside in μm unit or less of the sample piece to which the torsion load is applied.

  Although the above-mentioned patent document 1 shows tensile test evaluation of the micro sample piece in SEM, it does not show about torsion evaluation of the micro sample piece.

  An object of the present invention is to provide a charged particle beam apparatus capable of evaluating microscopic changes in a sample piece while applying a twisting force to a minute sample piece.

  If the micro sample piece to be evaluated has a cross section of, for example, about 10 μm, the risk that the micro sample piece is manufactured outside the evaluation device and mounted on the evaluation device itself is extremely high. Therefore, a sample piece of about 1 mm to 0.1 mm which can be handled manually is prepared in advance, and this sample piece is mounted on the evaluation device. Next, it is processed into a micro sample piece for torsion characteristic evaluation in the evaluation device, and the micro sample piece is subjected to torsion load and evaluated in situ. It is a good idea to observe the torsion state of the micro sample piece in situ with an SEM or a scanning transmission electron microscopy (hereinafter referred to as STEM). This evaluation device is a charged particle beam device according to the present invention.

  The charged particle beam apparatus of the present invention comprises a charged particle beam column for irradiating a charged particle beam to a sample piece, a sample piece holder for fixing the sample piece, and a sample stage for mounting the sample piece holder. The sample piece holder is disposed between the sample holder and the charged particle beam column, the sample piece holder capable of applying a twisting force to the sample piece about a torsion axis.

  In one aspect of the present invention, for example, the charged particle beam is at least one of a focused ion beam, an electron beam, and a gas gas ion beam.

  As one aspect of the present invention, for example, the sample piece holder holds a base removably disposed on the sample stage, a rotation control unit disposed on the base, and both ends of the sample piece And a shaft connecting the rotation control unit and the holding unit, the shaft is rotated based on a control signal of the rotation control unit, and the sample piece held by the holding unit is rotated.

  As one aspect of the present invention, for example, a heater that heats the sample piece is provided in the holding unit.

  According to the charged particle beam apparatus of the present invention, it is possible to easily observe changes in the properties of the sample piece while applying a twisting force to the minute sample piece.

It is a whole block diagram of the charged particle beam apparatus of embodiment which concerns on this invention. It is a principal part block diagram of the charged particle beam apparatus of embodiment, Comprising: It is a figure which shows the operation | movement of a sample stand, and the arrangement | positioning relationship with each lens barrel. It is a perspective view which shows the detailed structure of the sample piece holder mounted on a sample stand and holding a sample piece. It is a figure which shows another embodiment of a sample piece holder. It is a flowchart explaining the procedure which performs the twist evaluation of the sample by the charged particle beam apparatus of embodiment. It is a flowchart explaining another procedure which performs torsion evaluation of the sample by the charged particle beam device of an embodiment. (A)-(D) are figures for demonstrating the sample evaluation procedure by the charged particle beam apparatus of embodiment. It is a flowchart explaining the sample evaluation procedure by the charged particle beam apparatus of embodiment.

Hereinafter, an embodiment of a charged particle beam apparatus according to the present invention will be described.
FIG. 1 shows the overall configuration of the charged particle beam device 100 of the present embodiment. The charged particle beam apparatus 100 includes an FIB column (focused ion beam column) 1 for irradiating FIB as a first charged particle beam, and an electron beam (Electron Beam; hereinafter referred to as EB) as a second charged particle beam. ) And an GIB column (gas ion beam column) for irradiating a gas ion beam (hereinafter referred to as GIB) as a third charged particle beam. It has 3 and. The charged particle beam device 100 is an aspect of the charged particle beam device according to the present invention, and may have, for example, a configuration without a GIB column.

  The FIB column 1 includes a liquid metal ion source, and forms an FIB (focused ion beam) 1b by metal ions such as gallium. FIB 1 b is an ion beam which is focused to a diameter of about 1 μm or less and has a high current density. Therefore, irradiation of the sample piece 7 with the FIB 1 b enables processing such as drilling in the sample piece 7 and cutting of the side surface.

  The EB column 2 includes an electron source to form a focused EB (electron beam) 2b. By scanning the EB 2 b onto the processing surface, secondary electrons, reflection electrons, characteristic X-rays, and transmission electrons of a fine sample piece can be detected by the installed detector, and the respective image data are obtained.

  The GIB column 3 includes a gas ion source that generates gas ions such as a PIG (Penning Ionization Gauge) type or a duo plasmatron, and forms GIB 3 b (gas ion beam). The gaseous ion source can generate each ion using helium, argon, xenon, oxygen or the like as an ionizing gas, and adheres to the surface of the sample piece 7 by irradiating the sample piece 7 with low energy. Foreign matter and processing damage layers formed by FIB irradiation can be removed.

  The charged particle beam apparatus 100 further includes a secondary electron detector 4 for detecting a secondary electron signal of secondary electrons generated from the sample piece 7 by irradiation with FIB, EB or GIB. In addition, any one of a backscattered electron detector that detects a reflected signal of backscattered electrons (backscattered electrons) generated from the sample piece 7 by EB irradiation, a detector that detects an X-ray, and a transmitted electron detector that transmits a sample May be provided.

  The charged particle beam device 100 further includes a sample piece holder 6 for holding and fixing the sample piece 7 and a sample stage 5 for placing the sample piece holder 6. The sample table 5 is movable in the three XYZ axes described in FIG. 2, and can also tilt about the X axis and rotate about the Z axis.

  The charged particle beam device 100 further includes a sample stand control unit 15. The sample stand control unit 15 controls a drive mechanism (not shown) to move the sample stand 5 in three axial directions of XYZ. Furthermore, the sample stand control unit 15 can control the tilt drive unit 8 to tilt the sample stand 5 and can control the rotation drive unit 10 to rotate the sample stand 5.

  The charged particle beam device 100 further includes a sample piece holder control unit 60. The sample piece holder control unit 60 can apply a predetermined twisting force to the axial rotation of the sample piece 7 and the sample piece 7 by driving the sample piece holder 6 installed on the sample table 5. Details of the configuration and operation of the sample piece holder 6 will be described later.

  The charged particle beam apparatus 100 further includes an FIB control unit 11, an EB control unit 12, a GIB control unit 13, an image forming unit 14, and a display unit 18. The FIB control unit 11 controls the FIB irradiation from the FIB column 1. The EB control unit 12 controls the EB irradiation from the EB barrel 2. The GIB control unit 13 controls GIB irradiation from the GIB barrel 3. The image forming unit 14 forms an SEM image from the signal for scanning the EB and the signal of the secondary electrons detected by the secondary electron detector 4. The display unit 18 can display an observation image such as a SEM image and various control conditions of the apparatus. Further, the image forming unit 14 forms a SIM (Scanning Ion Microscopy) image from an image signal including a signal for scanning the FIB and a secondary electron signal of secondary electrons detected by the secondary electron detector 4. The display unit 18 can display a SIM image.

  The charged particle beam device 100 further comprises an input unit 16 and a control unit 17. The operator of the charged particle beam apparatus 100 inputs conditions for apparatus control into the input unit 16. The input unit 16 transmits the input information to the control unit 17. The control unit 17 transmits control signals to the FIB control unit 11, the EB control unit 12, the GIB control unit 13, the image forming unit 14, the sample stage control unit 15, the display unit 18, and the sample piece holder control unit 60, It controls the entire beam device 100.

  The charged particle beam device 100 further includes a calculation processing unit 21. The calculation processing unit 21 stores control conditions of various control units and can calculate an optimum value of various conditions. The calculation processing unit 21 stores an image formed by the image forming unit 14 and performs image processing, Image analysis is possible. For example, it is possible to analyze the deformation or displacement of a specific crystal grain from a plurality of SEM images when different loads are applied to a sample piece, or to extract only a minute crack generated on the sample surface by twisting.

  For control of the charged particle beam device 100, for example, the operator sets the irradiation area of FIB or GIB based on the observation image such as the SEM image or SIM image displayed on the display unit 18. The operator inputs a processing frame for setting an irradiation area on the observation image displayed on the display unit 18 by using the input unit 16. Furthermore, when the operator inputs a processing start instruction to the input unit 16, the control unit 17 transmits an irradiation area and processing start signal to the FIB control unit 11 or the GIB control unit 13, and the FIB control unit 11 GIB is irradiated from the GIB control unit 13 to the designated irradiation area of the sample piece 7. Thereby, FIB or GIB can be irradiated to the irradiation area | region which the operator input.

  The charged particle beam apparatus 100 further includes a gas gun 19 that supplies an etching gas to the area including the irradiation area of FIB, EB, or GIB of the sample piece 7. As an etching gas, a halogen gas such as a chlorine gas, a fluorine-based gas (such as xenon fluoride or fluorocarbon), or an iodine gas is used. By irradiating with FIB, EB or GIB while irradiating the etching gas that reacts with the material of the sample piece 7, the processing speed can be accelerated (so-called assist etching) compared to when the etching gas is not irradiated, or Only specific materials can be etched. In particular, gas-assisted etching by EB has an advantage of being able to perform etching without damaging the sample piece 7 by irradiation. The gas gun 19 can control at least one of movement of a nozzle (not shown) at the tip of the gas gun 19, selection of gas type, start and stop of gas irradiation, and the like by the gas gun control unit 20.

  FIG. 2 is a main part of the charged particle beam apparatus 100, showing the operation of the sample table 5 and the arrangement relationship between the respective lens barrels, and FIG. 1 is a schematic view for explaining the inside of the sample chamber shown by dotted lines. is there. The FIB irradiation axis (focused ion beam irradiation axis) 1a of the FIB column 1, the EB irradiation axis (electron beam irradiation axis) 2a of the EB column 2, and the GIB irradiation axis (gas ion beam irradiation axis) 3a of the GIB column 3 , And are arranged to intersect on the sample table 5. That is, the irradiation position of FIB 1 b of FIB column 1, the irradiation position of EB 2 b of EB column 2, and the irradiation position of GIB 3 b of GIB column 3 substantially coincide with each other on sample stage 5.

  When the sample table 5 is at the reference position, the upper surface of the sample table 5 is orthogonal to the FIB irradiation axis 1a, and the inclined axis 8a of the sample table 5 is the FIB irradiation axis 1a and the GIB irradiation axis 3a. The sample table 5 can be inclined by the inclination drive unit 8 at a position where the first surface 31 and the upper surface of the sample table 5 intersect with each other. That is, the tilt drive unit 8 as a tilt mechanism can be driven under the control of the control unit 17 and the sample stand control unit 15 and can tilt the sample stand 5 as shown by the arrow A.

  The second surface 32 formed by the FIB irradiation axis 1a and the EB irradiation axis 2a is in an orthogonal relationship with the first surface 31. With this configuration, it is possible to easily observe or image the processing surface by FIB 1 b irradiation by EB 2 b irradiation.

  The sample table 5 is also capable of rotating the sample piece 7 in a plane about the FIB irradiation axis 1 a axis by the rotation drive unit 10. That is, the rotation drive unit 10 as a rotation mechanism is driven under the control of the control unit 17 and further the sample stand control unit 15, and rotates the sample stand 5 in a plane as shown by the arrow B. For the rotation drive unit 10 as a rotation mechanism, various types such as a piezoelectric element and a servomotor can be used, and the type thereof is not particularly limited.

  Next, the configuration, operation, and operation of the sample piece holder 6 installed on the sample table 5 will be described. FIG. 3 shows an embodiment of the sample piece holder 6 (here, the sample piece holder 6A), and the sample piece holder 6A includes a pair of rotation control units 61 (61a, 61b) disposed on the base 64. And a pair of shafts 62 (62a, 62b) and clamps 63 (63a, 63b) as holding portions for holding the sample piece 7. The sample piece holder 6A can be detachably fixed to the upper surface of the sample table 5 via the base 64.

  The rotation control unit 61 shown in the present embodiment includes a rotatable piezoelectric element or the like, and for example, a piezoelectric element having a diameter of 3 mm and a length of 30 mm has an angular resolution of 0.1 degree. There is. The rotation of the shaft 62 can be controlled based on the control signal corresponding to the signal supplied from the sample piece holder control unit 60, and thus the sample piece 7 can be controlled.

A shaft 62 (62a, 62b) for connecting the rotation control unit 61 (61a, 61b) and the clamp 63 (63a, 63b) is rotatably held in each of the pair of rotation control units 61 (61a, 61b) It is done. The rotation axes of the shafts 62a and 62b are on the same rotation axis (torsion axis) AX, and as shown by the arrow C, the rotation control units 61a and 61b rotate the shafts 62a and 62b in the same direction at the same speed. The rotation control units 61a and 61b can start and stop the rotation of the shafts 62a and 62b at the same timing. The rotation control units 61a and 61b can also set one of the shafts 62a and 62b in a rotatable state and fix the other so as not to rotate. Thereby, a twisting force can be applied to the sample piece 7. In addition, after the shafts 62a and 62b are simultaneously operated by the rotation control units 61a and 61b to stop the target surface of the sample piece 7 at an angle that facilitates observation with the SEM, either one of the shafts 62a and 62b is fixed. The other can be rotated to apply a twisting force to the sample piece 7. At this time, the torsion axis of the sample piece 7 is the same as the rotation axis AX.
Each of the clamps 63a and 63b sandwiches and holds both ends of the sample piece 7. The sample piece 7 may be fixed to the clamp 63 (63a, 63b) with adhesive at both ends.

  The operator can input conditions (for example, minimum twist angle, final twist angle, twist speed) for applying a twisting force to the sample piece 7 at the input unit 16. The input unit 16 transmits the input information to the control unit 17. The control unit 17 transmits a control signal to the sample piece holder control unit 60, and the sample piece holder control unit 60 transmits a drive signal to the rotation control units 61a and 61b to rotate or stop the shafts 62a and 62b. it can.

  The rotation axis AX of the rotation control unit 61 is in parallel with the tilt axis 8 a of the sample table 5. In addition, since the rotation axis AX of the sample piece holder 6 is empty above ΔZ (for example, 5 mm) of the inclined axis 8a of the sample table 5, when processing or observing the sample piece 7, the sample table 5 is in the Z axis direction. By lowering by ΔZ, the FIB 1 b and the EB 2 b can be irradiated to almost the same place of the sample piece 7, and even if the sample piece 7 is rotated, the processed part by the FIB 1 b can be observed by the EB 2 b in situ.

  The sample piece 7 handled by the charged particle beam apparatus 100 is small, and in particular, the area to be subjected to torsion evaluation is as fine as less than 1 mm. Therefore, when the sample piece 7 is handled manually, it is easily deformed. Installation is difficult. Therefore, in the charged particle beam apparatus 100, the sample to be subjected to torsion evaluation has a shape in which the sample piece itself is not easily deformed even when handled manually by the sample piece holder, and after being fixed to a clamp, the charged particle beam apparatus 100 is installed. Process to the desired dimensions with FIB 1b or GIB 3b or both.

  The dimension example of the sample piece 7 is shown. The sample piece 7 before installation of the sample piece holder 6 has a total length of 30 mm, a total width of 10 mm, and a thickness of 100 μm (shown schematically in FIG. 3). It is machined from both sides so that a 5 mm constriction remains. The sample piece 7 is a fixed portion fixed at both ends by clamps 63, and a central neck portion (hatched portion in FIG. 3) is a portion for measuring mechanical characteristics (SEM evaluation). It is a so-called dumbbell-shaped test piece. The protrusions and cutting marks are removed so that the sample piece 7 does not cause stress concentration except at the constriction. This sample piece 7 is fixed to the clamp 63 and then irradiated with FIB 1 b or GIB 3 b or both to precede, for example, the narrowed portion to be 100 μm wide, 200 μm long, 100 μm thick It is processed to the shape which does not become discontinuous with the shape by machining. The shape of the sample piece is not limited to the above, and may be a flat plate that is not dumbbell-shaped, or may be a prism or a cylinder.

  Since processing with an ion beam such as FIB 1 b or GIB 3 b does not apply stress to the sample piece 7 during processing, there is no deformation due to processing or accumulation of internal stress. However, an FIB irradiation damaged layer having a thickness of about 10 nm is formed on the FIB processed surface. Although this FIB irradiation damage layer does not significantly change the mechanical properties of the sample piece, the FIB irradiation damage layer takes into consideration the case where the sample piece 7 is very small such as 1 μm or less, or the observation and analysis of the sample surface. It is desirable to remove The FIB radiation damaged layer can be removed (cleaned) by low energy GIB radiation. In addition, since the sample piece holder 6 can rotate 360 ° around the rotation axis AX without applying a load to the sample piece 7, the sample piece 7 can be rotated by rotating the sample piece 7 by 90 ° if the observation part is a square pole. Clean all sides to final sample pieces.

When cleaning of the four surfaces of the sample piece 7 is completed, the surface of interest is set to an angle perpendicular to the EB irradiation axis 2a, and the rotation control unit 61a at one end fixes the shaft 62a so as not to rotate, and rotates the other end. The control unit 61 b rotates the shaft 62 b gradually according to predetermined conditions, and applies a twisting force to the sample piece 7.
First, an SEM image is acquired in a no-load state, and then a load is gradually applied. The SEM image of the same area is acquired for each fixed load, and stored together with the torsional load value in the calculation processing unit 21. Load and image acquisition are repeated until the sample piece 7 breaks. This makes it possible to grasp the tendency of micro cracks due to twisting and the appearance of crack growth at the grain level. In addition, it is possible to observe and record in real time the shape change of crystal grains due to twisting and the occurrence of micro cracks.

Although the sample surface is observed by the SEM image in the above embodiment, the present invention is not limited to this, and the image may be formed by reflected electrons or X-rays generated from the sample by EB irradiation. The reflected electrons can be observed more sensitive to the surface state than the secondary electrons, and the elements constituting the sample piece 7 can be revealed by the X-ray signal.
Alternatively, the target portion of the sample piece 7 may be thinned or thinned to about several tens of nm, and the transmitted electron may be detected by a transmission electron detector (not shown) by EB irradiation and transmitted to form an image of the transmission image . Thereby, the state of the crystal grain inside a sample piece can be observed.

Next, another embodiment of the charged particle beam device according to the present invention will be described.
FIG. 4 shows a sample piece holder 6B used to evaluate the twisting characteristics of the sample piece 7 during heating. In this embodiment, the clamps 63a and 63b are provided with a heater (for example, ceramic heater) 65, and the sample piece 7 can be heated via the clamps 63a and 63b. The temperature of the sample piece 7 can be measured by an infrared radiation thermometer (not shown) from outside of the charged particle beam device without contact. With such a configuration, in addition to the twisting force, the temperature condition of the sample piece 7 can also be set, and the behavior of crystal grains on the surface of the twisted sample piece at various temperatures can be observed. In particular, in the case of the polycrystalline alloy AB in which the sample piece 7 is made of, for example, metal A and metal B, the characteristic X-ray generated by EB irradiation is generated as the behavior of crystal grains of metal A and crystal grains of metal B at various temperatures. It can be grasped from the element distribution of the EB irradiation range (SEM observation area) by detecting.

  As described above, the charged particle beam device according to the present invention makes it possible to know phenomena such as movement, sliding, and generation of cracks in crystal grains under heating and torsion load conditions of the sample piece 7. The installation location of the heater 65 is not necessarily limited to the clamp 63, and may be, for example, the shaft 62 or the rotation control unit 61. The heaters are at both ends of the sample piece 7 and have the same temperature characteristics ( It is desirable to operate at the same time with the temperature rate, maximum temperature, temperature drop rate, etc.). The heater may be installed only on one side of the sample piece 7.

  In the above embodiment, the charged particle beam apparatus 100 includes the charged particle beam apparatus 100 provided with the FIB column, the EB column, and the GIB column as the charged particle beam apparatus, but the present invention is not limited thereto. The present invention is also applicable to a charged particle beam apparatus in which a cylinder or any two of the above three lens barrels are combined. Further, in the above description, the FIB barrel 1 is disposed in the vertical direction, but the FIB barrel 1 and the EB barrel 2 may be interchanged and disposed.

FIG. 5 is a flow chart showing an example procedure of torsional evaluation of a minute sample piece in the charged particle beam apparatus.
First, the sample piece holder 6 on which the sample piece 7 is fixed is loaded in the charged particle beam apparatus, and it can be confirmed that the charged particle beam (for example, FIB, EB, GIB) loaded can exhibit predetermined performance. The point in time is taken as the start of the torsion evaluation flow (step S010). The sample piece 7 fixed to the sample piece holder 6 is processed to a predetermined shape and size and surface cleaning is performed to make a micro sample piece by using the rotation function of the sample table and the cutting function of the sample side surface by FIB. Perform (step S100). The rotation axis of the sample piece holder 6 is adjusted so that the sample surface to be observed can be observed by EB, and the shaft 62 (for example, the shaft 62a) is determined by one rotation control unit 61 (for example, the rotation control unit 61a). The rotation function of the shaft is fixed by the other rotation control unit (for example, the rotation control unit 61b) to rotate the shaft 62 (for example, the shaft 62b) at a predetermined speed, rotation angle and load to apply a twisting load to the sample piece 7 (Step S200). The sample piece 7 is irradiated with EB at a predetermined load and angle, and an image signal is acquired (step S300). The image signal is at least one of a secondary electron, a backscattered electron (backscattered electron), a transmitted electron, and an X-ray generated at the time of EB irradiation, and forms an image from these signals. In addition, the load of step S200 may be increased as necessary, and the image acquisition of step S300 may be repeated. When the sample piece 7 breaks or reaches a predetermined maximum load or maximum angle, a series of torsion evaluation flow ends (step S400). This is the basic flow of torsional evaluation using a charged particle beam device.

FIG. 6 is a flowchart for explaining another embodiment of the torsion evaluation procedure. Steps S010, S200, S300, and S400 in FIG. 6 are the same as the steps in FIG.
Step S100 of producing the micro sample piece in FIG. 5 is subdivided into steps S110 to S160 in the flow of FIG. The sample piece holder 6 installed on the sample stand 5 of the charged particle beam apparatus moves in the XYZ plane of the sample stand 5 and adjusts the rotation of the sample piece holder 6 so that the side surface serving as a torsion evaluation unit coincides with the FIB scanning direction (Step S110). Next, the specific surface of the sample piece 7 is irradiated with FIB to process the sample piece 7 (step S120). Then, GIB is irradiated to the surface which processed by FIB irradiation, and the processing damage layer by FIB irradiation is removed (cleaned) (step S130).

  In order to process and clean all the side surfaces of the sample piece 7, it is determined whether the process and the clean processing on all the side surfaces are completed each time the processing and the cleaning of each side surface are finished (step S140). In the side surface processing, if the processing and cleaning of all the side surfaces are not completed (N in step S140), the rotation axis of the sample piece holder 6 is rotated by a predetermined angle according to the number of the sample pieces 7 (step S145). The predetermined angle is, for example, 90 ° if the evaluation portion of the sample piece is a square pole. Subsequently, steps S120 and S130 are repeated. If it is determined in step S140 that processing and cleaning of all the side surfaces are completed (Y in step S140), the process proceeds to the next step. The determination in step S140 can be made in advance from the apparent number of sample pieces or the rotation angle in step S145 and the number of times step S120 (or S130) is performed.

  Steps S150 to S170 are preparatory steps for applying a twisting force to the sample piece 7, and the rotational axis of the sample piece holder 6 is adjusted so that the observation surface of the sample piece 7 to be focused becomes the optimum position for EB irradiation. (Step S150). Before applying a load to the sample piece 7, EB irradiation is performed on the sample piece 7 of interest to acquire an image (step S160). Thereafter, the rotation control unit 61 on one side of the sample piece holder 6 is fixed (locked) (step S170). The order of steps S160 and S170 may be reversed.

  Subsequently, the above-described steps S200 (load of torsional force) and S300 (image acquisition by EB irradiation to the sample piece) are performed. After step S300, it is determined whether the twisting force applied to the sample piece 7 has reached a predetermined twisting force or the maximum twisting angle (step S350). If the predetermined twisting force is not reached (N in step S350), steps S200 and S300 are repeated to further increase the load. If the predetermined twisting force is reached in step S350 (Y in step S350), or if the maximum twist angle is reached, the series of procedures is ended (step 400). If the sample piece 7 is broken in step S200, the process goes through step S300 to step S400.

  A series of flows from step S010 to step S400 shown in FIGS. 5 and 6 are the FIB control unit 11, the EB control unit 12, the GIB control unit 13, the image forming unit 14, the sample stand control unit 15, and the like in FIG. The sample piece holder control unit 60, the control unit 17, and the calculation processing unit 21 are operated automatically and continuously according to a predetermined program, and the twist evaluation of the sample piece 7 can be performed automatically. Also, the reproduced image can be automatically displayed on the display unit 18.

  That is, the FIB control unit 11 controls the FIB so as to process the sample piece with an acceleration voltage, an FIB diameter, a beam current, and an irradiation time which are predetermined in order to process a predetermined position by a predetermined cutting amount. The EB control unit 12 controls the EB so as to irradiate the sample surface at a predetermined acceleration voltage, EB diameter, beam current, irradiation range, and irradiation time. The GIB control unit 13 controls the GIB to irradiate the sample surface with a predetermined acceleration voltage, GIB diameter, beam current, irradiation range, and irradiation time on the processing surface after FIB processing. The sample piece holder control unit 60 controls the sample piece holder 6 so as to rotate the sample piece 7 at an optimum timing for FIB irradiation, EB irradiation, and GIB irradiation at an optimum timing. The image forming unit 14 takes in an image signal (at least one of a secondary electron signal, a reflected electron signal, a transmitted electron signal, an X-ray signal, etc.) obtained by EB irradiation to form an image of the EB irradiation unit. Do. The calculation processing unit 21 accumulates the image data formed by the image forming unit 14, processes and edits it, and displays it on the display unit at a predetermined timing as needed. Further, if necessary, the gas gun control unit 20 moves the nozzle to a predetermined position at a predetermined time, and controls the gas gun such as a predetermined gas type, irradiation time, irradiation and stop timing. The control unit 17 may be prepared in advance so as to integrally control the whole.

Next, another embodiment of the charged particle beam device according to the present invention will be described.
The sample piece holder 6 in the charged particle beam apparatus utilizes the fact that it can rotate 360 ° without applying a twisting force in a state where the sample piece 7 is mounted.
Measurement of crystal orientation from backscattered electron (reflected electron) signal obtained by irradiating a crystal sample with EB at a shallow angle with respect to the sample surface by using this apparatus, so-called electron beam backscattering diffraction image analysis Since (EBSD) can be performed, cutting of the sample piece 7 and EBSD evaluation can be repeatedly performed. Furthermore, three-dimensional EBSD evaluation can be performed by performing EBSD evaluation for each cutting of the sample piece 7.

FIGS. 7A to 7D are diagrams showing a procedure for acquiring an EBSD image of a polycrystalline square pole sample mounted on the sample piece holder 6, and a second process including an FIB axis and an EB axis. It is sectional drawing in the surface 32 (refer FIG. 2). The rotation axis of the sample piece holder 6 is perpendicular to the paper surface.
First, FIG. 7A is a view showing FIB processing of a specific surface of the square pole sample piece 7. The specific surface of the sample piece 7 is set parallel to the FIB irradiation axis 1a, and a predetermined thickness (for example, 100 nm) is cut by FIB 1b irradiation.

  The FIB irradiation damaged layer 7b may be formed on the processing surface 7a. FIG. 7B shows a state of removal of the FIB irradiation damaged layer 7b by GIB 3b irradiation immediately after processing by FIB 1b irradiation. The rotation axis AX is rotated so that the processing surface 7a has an angle of about 10 ° in the clockwise direction with respect to the plane formed by the FIB irradiation axis 1a and the GIB irradiation axis 3a. The FIB irradiation damaged layer 7b is removed (cleaned) by the GIB 3b irradiation, a layer of about 10 nm in thickness is removed from the FIB processed surface 7a, the clean surface 7c is exposed, and crystal grains appear prominently.

  FIG. 7C shows a state in which the clean surface 7c is irradiated with EB. The sample piece holder 6 is rotated by a predetermined angle so that the clean surface 7c and the EB irradiation axis 2a have a predetermined angle. If the angle between the FIB irradiation axis 1a and the EB irradiation axis 2a in the charged particle beam apparatus is, for example, -50 in the counterclockwise direction, the predetermined angle of the rotation axis AX of the sample piece holder 6 is It shall be 30 °. Therefore, it is rotated counterclockwise by -40.degree. From the position of FIG. 7 (B). With such a setting, the angle between the clean surface 7c and the EB irradiation axis 2a is relatively low at 20 °. It is important that the EB be irradiated at a low angle to such a clean viewing surface. After the sample piece holder 6 is rotated by a predetermined angle, the clean surface 7c is irradiated with the EB 2b, and the backscattered electrons 23 generated by the irradiation of the EB 2b are detected by a dedicated detector (not shown), and signal data is obtained. While being stored in the calculation processing unit 21, analysis can be performed to obtain an image indicating the crystal orientation of the clean surface 7 c to be observed. If necessary, the image may be displayed on the display unit 18.

FIG. 7D subsequently shows that the sample piece holder 6 has been returned to its original angle (the same position as in FIG. 7A). At this time, the sample piece 7 is moved in the direction by a predetermined thickness (Δt; for example, 100 nm) and cut by ΔD. Alternatively, the FIB may be cut by beam deflection by a predetermined ΔD without moving the sample piece 7 by a predetermined thickness. Hereinafter, rotation of the sample piece holder 6 determined in advance, cleaning of the processing surface (FIG. 7B), rotation of the sample piece holder 6 determined in advance, acquisition of backscattered electrons 23 (FIG. 7C), processing The above procedure such as the movement of the surface (FIG. 7D) is repeated, and the FIB processing is ended if the total cutting amount or the number of cuttings reaches a predetermined value. Note that the Δt value is not limited to the above, and a high resolution three-dimensional image can be constructed by reducing the Δt value to, for example, 10 nm.
From the image data stored so far and the data of each cutting amount (Δt), the calculation processing unit 21 can construct an image showing the three-dimensional arrangement of crystal grains. Once an image of three-dimensional grain arrangement can be constructed, an image showing crystal orientations of arbitrary cross sections in the image can be reconstructed.

  The rotation angle of the sample piece holder at the time of detecting the backscattered electrons 23 is not limited to the above, and depends on the installation position of the detector, and if the detector is at the 180 ° rotation target position, the sample piece holder 6 May be rotated clockwise by 110 ° to be incident on the clean surface 7c at a low angle of 20 °. Further, these angles are also an example, and an angle formed by the FIB irradiation axis 1a and the EB irradiation axis 2a, an incident angle of the EB 2b to the clean surface 7c, a positional relationship between a backscattered electron (backscattered electron) detector and a secondary electron detector. The rotation angle of the rotation axis AX of the sample piece holder 6 may be determined in advance.

  FIG. 8 is a flowchart showing a series of procedures described in FIG. A series of flow of three-dimensional EBSD measurement is started (step S500).

  First, the sample stand 5 and the sample piece holder 6 are set such that the predetermined surface of the sample piece 7 is at a position to receive the FIB irradiation (step S550). Next, one surface of the sample piece 7 is cut by FIB irradiation to a predetermined thickness (step S600). A damaged area (amorphous layer) is formed on the processing surface by FIB irradiation, and if it affects the observation by EB, it is removed (cleaned) by GIB irradiation (step S650). At this time, the sample piece holder 6 is pivoted to a predetermined position so that the processing surface of the FIB is at an appropriate position for GIB irradiation. Next, the sample piece holder 6 is rotated by a predetermined angle so as to be at an optimum position for EB irradiation (step S700). The processing surface cleaned in step S650 is irradiated with EB to detect backscattered electrons generated from the irradiated portion of the clean surface 7c (step S750). The detected signal is stored in the calculation processing unit 21 and is imaged by the image forming unit 14 to form a crystal orientation image of the processing surface on the display unit 18 (step S800). Although an EBSD image can be formed by this, it is only an image of a certain surface, and by setting the total amount of cutting in advance, a thick three-dimensional (three-dimensional) EBSD image can be formed.

  In step S850, after step S800, it is determined whether or not the cutting amount (cutting thickness or the number of times of cutting) by the predetermined FIB irradiation has been completed. If the predetermined amount has not been reached (N in step S850), the sample piece holder 6 is rotated by a predetermined angle so that the sample piece has the same orientation as in step S550 (S880). Then, the position of the processing surface is set to a predetermined position including the movement of the sample table. (S550). Thereafter, the above flow is repeated until step 850.

  If it is determined in step S850 that cutting (cutting thickness or number of cuttings) by predetermined FIB irradiation has been completed (Y in step S850), the EBSD image stored so far by the calculation processing unit as necessary A three-dimensional EBSD image is reconstructed from the information and the cutting thickness information, and displayed on the display unit (step S900). A series of flows are completed by these procedures, and the flow of three-dimensional EBSD measurement is ended (step S950).

  A series of flow from step S500 to step S950 described above controls the FIB control unit 11, the EB control unit 12, the GIB control unit 13, the image forming unit 14, the sample stand control unit 15, and the sample piece holder control unit 60 in FIG. The control unit 17 and the calculation processing unit 21 can be automatically operated continuously according to a predetermined program. The image may be displayed on the display unit 18 automatically.

  In addition, although the finish processing of the sample piece 7 is generally performed by GIB 3 b, instead of GIB 3 b, gas assisted etching by EB 2 b or FIB 1 b may be used. In the case of using FIB 1 b, it is desirable to change the beam energy of FIB 1 b in the process of forming the cross section 7 a of the sample piece 7 and the finishing process. That is, in processing for forming the processing surface 7 a of the sample piece 7, a sharp cross section is formed at high speed using a FIB 1 b accelerated at an accelerating voltage of 30 to 40 kV with a beam having a small beam diameter. By using a low acceleration FIB 1 b with an acceleration voltage of about 1 kV to 10 kV and using a beam with a small penetration length to the sample piece 7, processing with small damage is performed. This makes it possible to carry out a finishing process with less damage.

  Further, the details of the size of the sample piece holder 6 and the attachment method of the sample piece 7 are not particularly limited, and it is possible to select an optimum one according to observation.

  In the above embodiment, the detailed configuration of the sample piece holder 6 is shown. However, the configuration of the sample piece holder 6 is not limited to that of the embodiment. That is, the configuration of the sample piece holder 6 is not particularly limited as long as the sample piece holder 6 can apply a twisting force to the sample piece 7 around the torsion axis on the sample table 5. The shafts 62a and 62b and the rotation axis (torsion axis) AX are preferably substantially parallel to the upper surface of the sample table 5, but the present invention is not necessarily limited to such a form. In other words, as long as the rotation axis AX is not perpendicular to the sample table 5, the sample piece holder 6 can be arbitrarily configured.

  The present invention is not limited to the embodiment described above, and appropriate modifications, improvements, etc. are possible. In addition, the materials, shapes, dimensions, numerical values, forms, numbers, locations, and the like of each component in the above-described embodiment are arbitrary and not limited as long as the present invention can be achieved.

  According to the charged particle beam apparatus of the present invention, it is possible to easily observe changes in the properties of the sample piece while applying a twisting force to the sample piece.

1: FIB column (focused ion beam column)
1a: FIB irradiation axis (focused ion beam irradiation axis)
1b: FIB (focused ion beam)
2: EB column (electron beam column)
2a: EB irradiation axis (electron beam irradiation axis)
2b: EB (electron beam)
3: GIB column (gas ion beam column)
3a: GIB irradiation axis (gas ion beam irradiation axis)
3b: GIB (gas ion beam)
4: Secondary electron detector 5: Sample stand 6: Sample piece holder 7: Sample piece 7a: Machining surface 8: Inclined drive unit 8a: Inclined shaft 10: Rotational drive unit 11: FIB control unit 12: EB control unit 13: GIB control unit 14: image forming unit 15: sample stand control unit 16: input unit 17: control unit 18: display unit 19: gas gun 20: gas gun control unit 23: backscattered electrons (reflected electrons)
31: first surface 32: second surface 60: sample piece holder control unit 61: rotation control unit 62: shaft 63: clamp (holding unit)
64: base 65: heater 100: charged particle beam device AX: rotation axis (torsion axis)

Claims (2)

A charged particle beam column for irradiating a sample piece with a charged particle beam;
A sample piece holder for fixing the sample piece;
And a sample holder on which the sample piece holder is placed.
The specimen holder is between said charged particle beam column and the sample stage, Ri can der to provide a torsional force to the specimen about a torsional axis,
The sample piece holder is
A base removably disposed on the sample stage;
A rotation control unit disposed on the base;
A holding unit that holds both ends of the sample piece;
And a shaft connecting the rotation control unit and the holding unit.
The shaft is rotated based on a control signal of the rotation control unit, and the sample piece held by the holding unit is rotated.
A charged particle beam device , wherein a heater for heating the sample piece is provided in the holding unit . In the charged particle beam device according to claim 1,
The charged particle beam device is at least one of a focused ion beam, an electron beam, and a gas gas ion beam.

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