JP2019207878A - Ion milling device and ion milling method - Google Patents

Abstract

To provide an ion milling method capable of obtaining a desired processing content while preventing deterioration of a through-put.SOLUTION: An ion milling method that processes a sample 3 by irradiating with an ion beam 3101, the sample 3 of which at least one part is sealed with a mask by using an ion milling device, includes steps of: executing a wide region milling to the sample 3 for processing it in the wide region than a width of an ion beam 3101; searching a processing place 3103; and milling the processing place 3103 discovered by the wide region milling to a depth direction of the sample.SELECTED DRAWING: Figure 31

Description

  The present disclosure relates to an ion milling method, for example, an ion milling method for producing a sample observed with a scanning electron microscope (SEM), a transmission electron microscope (TEM), or the like.

  An ion milling device is a device for polishing the surface or cross section of metal, glass, ceramic, etc. by irradiating with an argon ion beam, etc., and a pretreatment device for observing the surface or cross section of a sample with an electron microscope It is suitable as.

  Conventionally, in cross-sectional observation of a sample with an electron microscope, the vicinity of a portion to be observed is cut using, for example, a diamond cutter or a thread saw, and then the cut surface is mechanically polished and attached to a sample stage for an electron microscope. Was observing. In the case of mechanical polishing, for example, a soft sample such as a polymer material or aluminum has a problem that the observation surface is crushed or deep scratches remain due to abrasive particles. In addition, for example, a hard sample such as glass or ceramic is difficult to polish, and a composite material in which a soft material and a hard material are laminated has a problem that cross-section processing is extremely difficult.

On the other hand, ion milling can process a soft sample without breaking the shape of the surface, and can polish a hard sample and a composite material. Further, there is an effect that a mirror-shaped cross section can be easily obtained. For example, Patent Document 1 discloses an ion milling apparatus that can reduce the generation amount of streak-like irregularities on a processed surface by irradiating an ion beam while tilting or rotating a sample.

JP 2014-139938 A

  As a result of intensive studies on the processing method for cross-sectional milling, the present inventor has obtained the following knowledge.

  Cross-section milling is to shield a part of the ion beam on a mask (shielding plate) arranged on the top of the sample and to sputter the cross section of the sample along the end face of the mask. As a result, a cross section of the sample along the end face of the mask can be obtained.

  However, when processing is required for a processing width (observation width) or a plurality of processing points that is greater than the ion beam width, the sample chamber is opened to the atmosphere, the processing position is changed, and the sample chamber is evacuated again and then additional processing is performed. There is a need. If such an additional process is performed, the throughput decreases.

  In view of such a situation, the present disclosure provides a processing technique capable of obtaining a desired processing content while preventing a decrease in throughput.

  In order to solve the above problems, the present disclosure provides an ion milling method in which an ion beam is applied to a sample that is at least partially shielded by a mask using an ion milling apparatus, and the sample is processed. On the other hand, performing wide-area milling that processes to a wider area than the width of the ion beam, searching for a processing location, and milling a processing location found by wide-area milling in the depth direction of the sample, We propose an ion milling method.

Further features related to the present disclosure will become apparent from the description of the present specification and the accompanying drawings. The aspects of the present disclosure are achieved and realized by elements and combinations of various elements and the following detailed description and appended claims.
It should be understood that the description herein is merely exemplary and is not intended to limit the scope of the claims or the application of this disclosure in any way.

  According to the above configuration, it is possible to improve the throughput.

It is a figure which shows the structural example 1 of the ion milling apparatus by this embodiment. It is a figure which shows the structural example of the sample mask unit 21 main body. It is a figure which shows the other structural example of the sample mask unit. It is a figure for demonstrating the method to make the cross section of a sample and a mask parallel. It is a figure which shows the structure of the sample stage extraction mechanism. It is a figure which shows the structural example of the optical microscope 40 which observes the shielding positional relationship of the mask 2 and the sample 3. FIG. It is a figure which shows the state which fixed the sample mask unit fine movement mechanism 4 which installed the sample mask unit 21 on the fixed base 42. FIG. It is a figure for demonstrating the method to match | combine the site | part which wants to carry out cross-sectional grinding | polishing of the sample 3 to the ion beam center. It is a figure for demonstrating the method of mirror-polishing the cross section of the sample 3 with an ion beam. It is a figure which shows the structural example 2 of the ion milling apparatus by this embodiment which has a structure different from the structural example 1 and enables both cross-sectional milling and plane milling. It is a figure which shows the structural example of the sample mask unit fine movement mechanism 4 which installed the sample mask unit 21 mounted in the ion milling apparatus shown in FIG. It is a figure for demonstrating the rotation mechanism provided in the sample unit base 5, and which rotates the mask unit fixing | fixed part 52. FIG. It is a figure which shows the rotation mechanism which rotates the mask unit fixing | fixed part 52 by rotating the shaft coupling 53. FIG. It is a figure which shows a mode that the sample mask unit fine movement mechanism 4 is installed in the optical microscope 40 for process position adjustment. It is a figure which shows the structural example of a rotation inclination mechanism, and is a figure which shows the structure for the part A more specifically enclosed by the dotted line of FIG. It is a figure which shows the mechanism for rotating the rotary body 9 by a shaft coupling. It is a figure which shows the structural example of the slide milling holder (slide movement mechanism) 70 for slidingly moving the sample mask unit fine movement mechanism 4 to a X-axis direction. It is a figure which shows the connection relation between apparatuses at the time of setting the process position of ion milling. It is a flowchart for demonstrating the procedure of a process position setting process. 5 is a diagram illustrating an example of the arrangement of buttons for setting a target position in a control BOX 80. FIG. It is a figure which shows the specific example 1 of the processing area setting method of wide area milling. It is a figure which shows the specific example 2 of the processing area setting method of wide area milling. It is a figure which shows the example of an operation screen of the process area setting in wide area milling. It is a figure for demonstrating the process sequence of the sample 3 by wide area | region milling. It is a figure which shows the range of a slide movement operation | movement and reciprocation inclination operation | movement in case a slide movement mechanism (slide milling holder 70) is installed under the rotary body 9. FIG. FIG. 5 is a diagram showing a state of rotation and slide movement of a sample mask unit 21 when adopting a configuration in which a slide moving mechanism (slide milling holder 70) is installed under a rotating body 9. FIG. 6 is a diagram showing a range of a slide movement operation and a reciprocating tilt operation when a slide movement mechanism (slide milling holder 70) is installed on the rotating body 9. It is a figure which shows the specific example of the process area | region setting method of multipoint milling. It is a figure for demonstrating the process procedure 1 of the sample 3 by multipoint milling. It is a figure for demonstrating the process procedure 2 for suppressing the redeposition generation | occurrence | production by multi-point milling. It is a figure which shows the example of 1 utilization of wide area milling. It is a figure for demonstrating the method to fix the some sample from which thickness differs. It is a figure which shows the state which arranged the sample from which thickness differs in multiple numbers, and was fixed to the mask. It is a figure which shows a mode that the sample from which thickness differs is moved to an observation apparatus after processing and observed. It is a figure which shows the connection relation between the apparatuses at the time of setting the process position of ion milling by a modification. It is a flowchart for demonstrating the procedure of the process position setting process by a modification.

  In general, when processing is required for a processing width (observation width) greater than the ion beam width or a plurality of processing points, the sample chamber is opened to the atmosphere, the processing position is changed, the sample chamber is evacuated again, and additional processing is performed. There is a need. If such an additional process is performed, the throughput decreases. In addition, there is a high possibility that redeposition occurs on the first processed surface.

  Therefore, the present embodiment generates a processed surface having a desired width (wider than the ion beam width) on the sample without generating redeposition due to ion milling as much as possible while improving throughput, and / or It is possible to generate a plurality of processing points (processing points) on the sample. The present specification discloses at least a mechanism and a processing procedure that allow a processing surface having a desired width to be generated and a plurality of processing points to be generated by one processing.

  Hereinafter, this embodiment will be described with reference to the drawings. In this embodiment, an ion milling apparatus equipped with an ion source for irradiating an argon ion beam will be described as an example. However, the ion beam is not limited to an argon ion beam, and various ion beams can be applied. It is.

<Configuration example of ion milling device>
(I) Device configuration example 1
FIG. 1 is a diagram illustrating a configuration example 1 of an ion milling apparatus 100 according to the present embodiment.
An ion milling apparatus 100 according to FIG. 1 includes a vacuum chamber 15, an ion source 1 attached to the upper surface of the vacuum chamber, a sample stage 8 provided on the front surface of the vacuum chamber 15, and a sample extended from the sample stage 8. A unit base 5, a sample mask unit fine movement mechanism 4 placed on the sample unit base 5, a sample mask unit 21 placed on the sample mask unit fine movement mechanism 4, a vacuum exhaust system 6, and a vacuum And a linear guide 11 provided on the front surface of the chamber 15. The sample 3 and the mask 2 are placed on the sample mask unit.

  A sample mask unit fine movement mechanism 4 is mounted on the sample unit base 5. Mounting is performed by bringing the lower surface of the sample mask unit fine movement mechanism 4 (the opposite side of the mask surface irradiated with the ion beam) and the upper surface of the sample unit base 5 into contact with each other and fixing with screws. The sample unit base 5 is configured to be able to rotate and tilt at an arbitrary angle with respect to the optical axis of the ion beam, and the direction and angle of rotation are controlled by the sample stage 8. By rotating and tilting the sample stage 8, the sample 3 placed on the sample mask unit fine movement mechanism 4 can be set at a predetermined angle with respect to the optical axis of the ion beam. Further, the rotational tilt axis of the sample stage 8 and the position of the upper surface of the sample (the lower surface of the mask) are matched to produce a smooth processed surface efficiently. Further, the sample mask unit fine movement mechanism 4 is configured to be movable in the front and rear, right and left directions in the direction perpendicular to the optical axis of the ion beam, that is, in the X and Y directions.

  The sample unit base 5 is arranged via a sample stage 8 (rotation mechanism) mounted on a flange 10 that also serves as a part of the container wall of the vacuum chamber 15, and the flange 10 is pulled out along the linear guide 11. When the vacuum chamber 15 is opened to the atmospheric state, the sample unit base 5 is configured to be pulled out of the vacuum chamber 15. In this way, the sample stage drawing mechanism is configured.

  FIG. 2 is a diagram illustrating a configuration example of the main body of the sample mask unit 21. 2A is a plan view, and FIG. 2B is a side view. In the present embodiment, a configuration in which at least the sample holder 23 and its rotation mechanism, and the mask 2 and its fine adjustment mechanism are integrally configured is referred to as a sample mask unit (main body) 21. In FIG. 2, a sample holder rotating ring 22 and a sample holder rotating screw 28 are provided as a rotating mechanism of the sample holder 23. By rotating the sample holder rotating screw 28, the sample holder 23 can be rotated perpendicularly to the optical axis of the ion beam. The sample holder rotating ring 22 is configured to rotate by turning the sample holder rotating screw 28, and returns with the spring pressure of the reverse rotating spring 29.

  The sample mask unit 21 has a mechanism that can finely adjust the position and rotation angle of the mask, and can be attached to and detached from the sample mask unit fine movement mechanism 4. In the present embodiment, the sample mask unit 21 and the sample mask unit fine movement mechanism 4 have two parts. However, the sample mask unit 21 and the sample mask unit 4 may be composed of one part. The fine movement mechanism will be described separately).

  The mask 2 is fixed to the mask holder 25 with a mask fixing screw 27. The mask holder 25 moves along the linear guide 24 by operating a mask fine adjustment mechanism (that is, a mask position adjustment unit) 26, thereby finely adjusting the positions of the sample 3 and the mask 2. The sample holder 23 is inserted and fixed to the sample holder rotating ring 22 from the lower side. The sample 3 is bonded and fixed to the sample holder 23 (for example, bonded and fixed with carbon paste, white wax, double-sided tape, etc.). The position of the sample holder 23 in the height direction is adjusted by the sample holder position control mechanism 30, and the sample holder 23 is brought into close contact with the mask 2.

  FIG. 3 is a diagram illustrating another configuration example of the sample mask unit 21. In this configuration example, the sample holder fixing bracket 35 for holding the sample holder 23 is used, and the other configuration is basically the same as the configuration example shown in FIG. FIG. 3A shows a state in which the sample holder 23 to which the sample 3 is fixed is mounted in the sample mask unit 21, and FIG. 3B shows that the sample holder 23 to which the sample 3 is fixed is removed from the sample mask unit 21. Indicates the state.

  FIG. 4 is a diagram for explaining a method of making the cross section of the sample and the mask parallel to each other. The sample holder rotating screw 28 is rotated to adjust the position in the X1 direction, and fine adjustment is performed under the microscope as described later so that the cross section of the sample 3 and the ridge line of the mask 2 are parallel. At this time, the mask fine adjustment mechanism 26 is set to rotate so that the cross section of the sample 3 slightly protrudes from the mask, for example, approximately 50 μm.

  FIG. 5 is a diagram showing a configuration of the sample stage drawing mechanism 60. The sample stage drawing mechanism 60 includes the linear guide 11 and the flange 10 fixed to the linear guide 11. The sample unit base 5 fixed to the sample stage mounted on the flange 10 is drawn from the vacuum chamber 15 along the linear guide 11. It is. In accordance with this operation, the sample mask unit fine movement mechanism 4 in which the sample mask unit 21 is installed on the sample unit base 5, that is, the mask 2, the sample holder 23, and the sample 3 are pulled out from the vacuum chamber 15.

  In this embodiment, the sample mask unit fine movement mechanism 4 provided with the sample mask unit 21 has a structure that is detachably fixed to the sample unit base 5. Accordingly, when the sample mask unit fine movement mechanism 4 provided with the sample mask unit 21 is pulled out of the vacuum chamber 15, the sample mask unit fine movement mechanism 4 provided with the sample mask unit 21 is detachable from the sample unit base 5. (Sample mask unit 21 attach / detach standby)

  FIG. 5 is a view showing a state in which the sample mask unit fine movement mechanism 4 provided with the sample mask unit 21 is detached from such a detachable state. This attachment and detachment can be performed manually or can be performed with an appropriate instrument.

  FIG. 6 is a diagram illustrating a configuration example of the optical microscope 40 that observes the shielding positional relationship between the mask 2 and the sample 3. As shown in FIG. 6, it is configured separately from the vacuum chamber 15 and can be arranged at an arbitrary location. The optical microscope 40 includes a known loupe 12 and loupe fine movement mechanism 13. Further, the optical microscope 40 includes a fixed base 42 for installing the sample mask unit fine movement mechanism 4 on which the sample mask unit 21 removed from the observation table 41 is installed. The sample mask unit fine movement mechanism 4 on which the sample mask unit 21 is installed is installed on the fixed base 42 at a fixed position with reproducibility by a positioning shaft and a hole.

  FIG. 7 is a view showing a state in which the sample mask unit fine movement mechanism 4 provided with the sample mask unit 21 is fixed on the fixed base 42. In this way, after the sample mask unit fine movement mechanism 4 provided with the sample mask unit 21 is fixed on the fixing base 42, the portion of the sample to be polished by the method described with reference to FIG. 8).

  FIG. 8 is a diagram for explaining a method of aligning a portion of the sample 3 whose cross section is to be polished with the center of the ion beam. A photosensitive paper, copper foil, or the like is attached to the sample holder 23, and the trace formed by irradiating the ion beam, that is, the center of the ion beam and the center of the loupe are driven by the loupe fine movement mechanism 13 to drive X2 and Y2. As a result, the ion beam center and the center of the optical microscope have a one-to-one correspondence. The position adjustment is performed at the timing of the cleaning process. Then, the photosensitive paper or copper foil used for alignment is removed from the sample holder 23, and the sample mask unit fine movement mechanism 4 on which the sample mask unit 21 after the sample 3 is mounted is installed on the fixed base 42. By adjusting the position of the sample mask unit fine movement mechanism 4 in the X3 and Y3 directions so that the portion to be subjected to cross-section polishing is aligned with the center of the loupe, the center of the ion beam and the portion to be cross-sectional polished can be matched. Thus, when adjusting the shielding positional relationship between the mask 2 and the sample 3, the sample mask unit fine movement mechanism 4 provided with the sample mask unit 21 is detached from the sample unit base 5 and mounted on the fixed base 42 of the optical microscope 40. Then, the mask 2 has its shielding position relative to the sample 3 adjusted by a mask position adjustment unit (mask fine adjustment mechanism).

  FIG. 9 is a diagram for explaining a method of mirror-polishing the cross section of the sample 3 with an ion beam. When the argon ion beam is irradiated, the sample 3 not covered with the mask 2 can be removed along the mask 2 in the depth direction, and the surface of the cross section of the sample 3 can be mirror-polished.

  As described above, the sample mask unit fine movement mechanism 4 provided with the sample mask unit 21 including the mask 2 in which the shielding positional relationship with respect to the sample is adjusted during ion milling is returned to the sample unit base 5 and attached.

  As described above, when adjusting the shielding positional relationship between the mask 2 and the sample 3, the sample mask unit fine movement mechanism 4 on which the sample mask unit 21 is installed is detached from the sample unit base 5 and mounted on the fixed base 42 of the optical microscope 40. The sample mask unit fine movement mechanism 4 in which the sample mask unit 21 provided with the mask 2 having the adjusted mask position relative to the sample is adjusted in the vacuum chamber 15 is adjusted during ion milling. An ion milling method is configured to return and attach to the sample unit base 5.

(Ii) Device configuration example 2
FIG. 10 is a diagram showing a configuration example 2 of the ion milling apparatus 100 according to the present embodiment, which has a configuration different from the configuration example 1 and enables both cross-sectional milling and planar milling.

  The ion milling apparatus 100 includes a vacuum chamber 15, a processing observation window 7 provided on the upper surface of the vacuum chamber 15, an ion source 1 provided on the left side surface (or right side surface) of the vacuum chamber 15, and an ion source. 1 is mounted on the sample unit base 5, the flange 10 provided on the side surface different from the side surface on which the 1 is provided, the sample stage 8 provided on the flange 10, the sample unit base 5 extending from the sample stage 8, and the sample unit base 5. The sample mask unit fine movement mechanism 4 and the sample mask unit 21, the sample stage 8 provided on the front surface of the vacuum chamber 15, the shutter 101 provided between the sample and the processing observation window 7, and the vacuum exhaust system 6 are provided. I have. The sample mask unit 21 has a mask 2 on which a sample 3 is placed.

  The shutter 101 is installed to prevent sputtered particles from accumulating on the processing observation window 7. The vacuum chamber 15 usually has a box shape that forms a space for forming a vacuum atmosphere, or a shape similar thereto, but the processing observation window 7 is located above the box (in a gravitational environment, The ion source 1 is provided on the side wall surface of the box (the surface adjacent to the upper surface of the box and perpendicular to the direction of the gravitational field). That is, the processing observation window 7 is provided on the wall surface of the vacuum chamber. In addition to providing a window that can be vacuum-sealed, an optical microscope (including an observation window) or an electron microscope can be installed in the opening for the processing observation window.

  FIG. 11A is a diagram showing a configuration example of the sample mask unit fine movement mechanism 4 in which the sample mask unit 21 mounted on the ion milling apparatus shown in FIG. 10 is installed. The basic configuration is the same as the configuration shown in FIGS. 2 and 3 except that the sample mask unit fine movement mechanism 4 on which the sample mask unit 21 is mounted is provided with a mask unit fixing portion 52. Yes. Further, the fixing method of the sample holder 23 is different from the configuration of FIG. That is, the sample holder 23 is configured so that the key portion 231 of the sample holder 23 is inserted into the sample holder rotating ring 22 (the shape obtained by dividing the ring in half) from the lower side and fixed with screws (FIG. 11). (See (b)). By adopting such a fixing method, the processed surface of the sample 3 can be observed from the processing observation window 7.

  FIG. 12 is a view for explaining a rotation mechanism provided on the sample unit base 5 for rotating the mask unit fixing portion 52. The sample unit base 5 is provided with a rotating body 9 on which a sample holding member (member holding the sample including the sample mask unit fine movement mechanism 4) can be placed. The rotating body 9 functions as a support base that supports the sample holding member. The sample unit base 5 includes a rotating body 9, a gear 50, and a bearing 51. The sample mask unit fine movement mechanism 4 is mounted by screwing the mask unit fixing part 52 with screws by bringing the fixing surface (rear surface) of the sample mask unit fine movement mechanism 4 into contact with the upper surface of the rotating body 9 of the sample unit base 5. The sample unit base 5 is not rotated and inclined, but can be rotated and inclined at an arbitrary angle with respect to the optical axis of the ion beam irradiated from the side surface direction of the vacuum chamber 15 by the rotating body 9 mounted on the sample unit base 5. The sample stage 8 is configured to control the rotational tilt direction and tilt angle.

  Here, as a method of rotating and tilting the rotating body 9 of the sample unit base 5, there is a method of rotating the sample stage 8 as shown in FIG. 12, or a method of rotating the shaft coupling 53 as shown in FIG. However, either one can be used. By rotating and tilting the rotating body 9 of the sample unit base 5, the sample 3 placed on the sample mask unit fine movement mechanism 4 can be set at a predetermined angle with respect to the optical axis of the ion beam. Further, the rotation axis of the rotating body 9 of the sample unit base 5 and the position of the sample upper surface (mask lower surface) are matched to produce an efficient smooth processed surface.

  FIG. 14 is a diagram illustrating a state in which the sample mask unit fine movement mechanism 4 is installed in the optical microscope 40 in order to adjust the processing position. In addition, the method of using the lower surface of the sample mask unit fine movement mechanism 4 without using the mask unit fixing part 52 may be used for installing the apparatus on the optical microscope 40 separately from the apparatus. FIG. 14 differs from FIG. 6 in that the loupe fine movement mechanism 13 for adjusting the beam center and the loupe center is performed on the fixed base 42 side. The loupe fine movement mechanism 13 may employ either this example or the example shown in FIG. Otherwise, the same operation as in the example of FIG. 6 is performed.

  FIG. 15 is a diagram illustrating a configuration example of the rotating and tilting mechanism, and more specifically, illustrates a configuration of a portion A surrounded by a dotted line in FIG. In the ion milling apparatus according to the configuration example 2 (FIG. 10), as shown in FIG. 15, a rotation function is provided in the rotation tilt mechanism of the sample, and a tilt mechanism having a rotation tilt axis perpendicular to the ion beam axis is provided. It has been. The rotary tilt mechanism rotates the rotating body 9 (not shown in FIG. 15) through the shaft and the gear 50 with the rotational force of the motor 55. By doing so, it is possible to realize an eccentric mechanism that shifts the ion beam axis when the tilt angle is 90 degrees and the rotation axis of the sample mask unit fine movement mechanism 4. As shown in FIG. 16, a system using a shaft coupling may be used. However, when a shaft coupling is used, it is desirable that the shaft coupling is installed in the rotation inclined portion as shown in FIG. 16, and the eccentric mechanism (movement in the Y-axis direction) is installed below the rotating body 9 of the sample unit base 5.

  As shown in FIGS. 15 and 16, the ion milling device is provided with a sample rotation function, and the ion beam incident angle and the amount of eccentricity are arbitrarily determined. However, it is possible to perform plane milling (smoothly processing a plane perpendicular to the ion beam axis (when the tilt angle of the sample stage is 90 degrees)).

<Slide movement mechanism to realize wide area milling and multi-point milling>
Hereinafter, in the ion milling apparatus 100 according to the configuration of FIGS. 1 and 10 (including any of FIGS. 12, 13, 15, and 16), a slide moving mechanism for realizing wide area milling and multipoint milling. Will be explained. Here, wide area milling means that a region on the sample having a width wider than the ion beam width is processed. Multi-point milling means that a plurality of locations on the sample are processed (particularly, in this embodiment, a plurality of locations are processed automatically).

  The ion milling apparatus 100 capable of both wide-area milling and multi-point milling includes a slide movement mechanism (also referred to as a slide drive mechanism) that can move (slide) in a direction perpendicular to the optical axis of the ion beam, and is a vacuum. It is necessary to slide the sample mask unit 21 in the chamber. It is desirable that the sliding direction and the edge of the mask 2 have a parallel relationship. Further, it is desirable that the position of the rotary tilt axis does not move even when the slide movement is performed (the reason will be described later with reference to FIGS. 25 to 27). In order to realize such an ion milling apparatus, the following configuration is desirable. In the present embodiment, a case where a motor that is a drive source in the X-axis direction is installed in the vacuum chamber (when the motor is driven) is described, but it may be installed outside the chamber.

  In order to perform wide-area milling and multi-point milling, it is desirable that the sample mask unit fine movement mechanism 4 can be driven in the X-axis direction (see FIG. 10) in the vacuum chamber 15 in addition to the configuration of FIG. . Specifically, the X-direction drive source of the sample mask unit fine movement mechanism 4 is a motor, so that the X-direction drive in the vacuum chamber 15 is enabled.

  FIG. 17 is a diagram illustrating a configuration example of a slide milling holder (slide moving mechanism) 70 for sliding the sample mask unit fine movement mechanism 4 in the X-axis direction. The slide milling holder 70 is provided with an X gear 71 on the drive shaft in the X-axis direction of the sample mask unit fine movement mechanism 4. A motor unit 72 is installed on the lower surface side of the sample mask unit fine movement mechanism 4. The motor unit 72 includes a motor, an M gear 73, a cover, and the like. The motor unit 72 does not have to be directly attached to the rotation shaft of the motor. A step (gear that contacts the X gear 71) is assembled. The sample mask unit fine movement mechanism 4 and the motor unit 72 may be either an integral type or a separate type, but are described as a separate type here. In the separation type, even when the motor unit 72 is removed, normal cross-sectional milling is possible (manual adjustment method).

  The assembly of the sample mask unit fine movement mechanism 4 and the motor unit 72 is fixed with screws by maintaining a reproducible positional relationship by the positioning shaft and the hole. By doing so, the X gear 71 of the sample mask unit fine movement mechanism 4 and the M gear 73 of the motor unit 72 come into contact with each other. Therefore, when the motor starts to rotate, the X gear 71 rotates through the M gear 73, and the drive shaft in the X axis direction of the sample mask unit fine movement mechanism 4 rotates. Therefore, the sample 3 (sample 3 fixed to the sample mask unit 21) starts to move (slide) in the X-axis direction. By setting it as the above structure, the ion milling apparatus without the movement of a rotation inclination axis | shaft, performing a slide is realizable. In addition, the said slide milling holder 70 will be arrange | positioned at the upper part of the rotary body 9 in the ion milling apparatus shown by FIG. 10, FIG. Further, the slide milling holder 70 is placed on the sample unit base 5 in the ion milling apparatus shown in FIG.

<Processing contents from machining target position setting to machining start>
FIG. 18 is a diagram illustrating a connection relationship between apparatuses when setting a processing position of ion milling. FIG. 19 is a flowchart for explaining the procedure of the processing position setting process. Referring to FIGS. 18 and 19, an ion milling operation method using a slide milling holder 70 in which the sample mask unit fine movement mechanism 4 provided with the sample mask unit 21 and the motor unit 72 are combined (sample 3 is the sample mask unit 21). Will be described. The power for driving the motor is supplied from the main body control unit 103 of the ion milling apparatus 100 via a motor cable (outside) 74 and a motor cable (inside) 75.

(I) Step 1901
The user (operator) mounts the slide milling holder 70 on the fixed base 42 (see FIG. 14) of the optical microscope 40 and slide mills the motor cable (outside) 74 extending from the control unit 103 via the optical microscope side driver 102. Connect to the motor unit of the holder 70.

(Ii) Step 1902
When the process of step 1901 is completed and the processing position setting process is started, the control unit 103 executes an initialization operation of the slide milling holder 70. Specifically, the slide milling holder 70 mounted on the optical microscope 40 is moved to a reference position (for example, the origin).

(Iii) Step 1903
After the initialization operation is completed, the user presses an arrow button provided on the operation unit (for example, touch panel) 81 or on the control box (for example, separated from the control unit 103 and installed near the optical microscope 40) 80. Then, the slide milling holder 70 loaded with the sample 3 is moved to the target position (position to be processed) (X-axis direction: X3 in FIG. 8), and a determination button provided on the control BOX 80 or the like is pressed. The movement in the X-axis direction is performed by motor drive. The adjustments other than the X-axis movement are the same as the operation method according to the description of FIG. When the movement in the X-axis direction is performed, the control unit 103 obtains information on the target position (information on the number of pulses corresponding to the number of times the arrow button has been pressed to move the slide milling holder 70 to the target position). get. The target position can also be set by a numerical value (for example, distance). In this case, for example, the set numerical value (distance) is converted into the number of pulses.

(Iv) Step 1904
The control unit 103 acquires the information on the target position acquired in step 1903 (distance from the origin: the number of pulses generated when moving to the target position), and stores it in a memory (not shown) in the control unit 103. ).

(V) Step 1905
When the setting of the target position using the optical microscope 40 is completed, the user removes the motor cable (outside) 74 connected to the slide milling holder 70 from the motor unit 72 and removes the slide milling holder 70 from the optical microscope 40. Remove from the fixed base 42. The control unit 103 detects that the motor cable (outside) 74 has been removed.

(Vi) Step 1906
Next, the user places the slide milling holder 70 removed from the optical microscope 40 on the rotating body 9 (in the case of the ion milling device configuration of FIG. 12) of the ion milling device installed in the vacuum chamber 15 or the sample unit base 5. It is mounted on (in the case of the ion milling apparatus structure of FIG. 1). Then, the user connects the motor cable (inner) 75 extending from the control unit 103 to the motor unit 72 of the slide milling holder 70 via the vacuum chamber side driver 104. The control unit 103 detects that the motor unit 72 of the slide milling holder 70 is connected to the motor cable (inner) 75.
Then, the user closes the sample stage drawing mechanism 60 and evacuates the vacuum chamber 15 with the evacuation system 6 to obtain a vacuum state.

(Vii) Step 1907
The control unit 103 executes an initialization operation of the slide milling holder 70. Specifically, the reference position (for example, the origin) of the slide milling holder 70 mounted on the ion milling apparatus is moved.

  A user injects argon gas between the electrodes in the ion source 1, applies a high voltage, and starts discharge. In this state, an acceleration voltage is applied, an ion beam is ejected, and processing is started.

(Viii) Step 1908
The control unit 103 reads information on the target position stored in the memory, controls the vacuum chamber side driver 104 so that the processing position on the sample is set at the target position, and controls the motor of the motor unit 72. Drive.

  In the ion milling apparatus, the rotating body 9 (in the case of the configuration example of the ion milling apparatus in FIG. 10) or the sample stage 8 (in the case of the configuration example of the ion milling apparatus in FIG. 1) is reciprocally inclined to an arbitrary angle, and By performing the slide reciprocating drive (see FIG. 24) of the slide milling holder 70, it is possible to obtain a processed surface in a wide area. (The range of the slide reciprocating drive is between the positions set under the optical microscope 40.) Note that the slide reciprocating drive may be either continuous or intermittent. In addition, as an example of intermittent drive, it is considered that 0.1 mm slide is processed after 10 seconds processing, then 0.1 mm slide is processed after 10 seconds processing, and the stop (processing) time and slide distance are input. It is done.

<Processing contents from machining target position setting to machining start (modification)>
FIG. 35 is a diagram illustrating a connection relationship between apparatuses when setting a processing position of ion milling according to a modification. FIG. 36 is a flowchart for explaining the procedure of the machining position setting process according to the modification. 35 and 36, an ion milling operation method (operation from a state in which the sample 3 is installed in the sample mask unit 21) using the sample mask unit fine movement mechanism 4 in which the sample mask unit 21 is installed will be described. To do.

  In FIG. 18 described above, the slide milling holder 70 having the motor unit 72 is moved between the vacuum chamber 15 and the optical microscope 40 (the same motor is used). And a driving unit (including a motor) are provided on the optical microscope 40 side. For this reason, it is not necessary to move the slide milling holder 70 itself between the vacuum chamber 15 and the optical microscope 40. Therefore, in this case, the sample mask unit fine movement mechanism 4 provided with the sample mask unit 21 may be moved back and forth between the vacuum chamber 15 and the optical microscope 40. At this time, it is not necessary to connect or disconnect the cable. In the processing position setting processing procedure shown in FIG. 36, Step 3601, Step 3602, and Step 3603 are executed instead of Step 1901, Step 1905, and Step 1906 in FIG. Only steps 3601 to 3603 different from those in FIG. 19 will be described below.

(I) Step 3601
The user (operator) mounts the sample mask unit fine movement mechanism 4 on an optical microscope 40 having a drive unit. A motor cable (outside) 74 extending from the control unit 103 via the optical microscope side driver 102 is connected to the motor unit 3502 on the optical microscope 40 side. For this reason, unlike step 1901 in FIG. 19, a motor cable (outside) connection step is not required (the sample mask unit fine movement mechanism 4 only needs to be mounted on the optical microscope 40).

(Ii) Step 3602
When the setting of the target position using the optical microscope 40 is completed, the user removes the sample mask unit fine movement mechanism 4 from the optical microscope 40 having the drive unit. At this time, the control unit 103 detects that the sample mask unit fine movement mechanism 4 is removed from the optical microscope 40, and the alignment in the optical microscope 40 is completed.

(Vi) Step 3603
When the alignment on the optical microscope 40 side is completed, the user mounts the sample mask unit fine movement mechanism 4 removed from the optical microscope 40 in the vacuum chamber 15 having the drive unit. A motor cable (inner) 75 extending from the control unit 103 via the vacuum chamber side driver 104 is connected to the motor unit 3501 on the vacuum chamber 15 side. Therefore, unlike step 1906 in FIG. 19, the motor cable (inner) connection step is not required (the sample mask unit fine movement mechanism 4 only needs to be mounted in the vacuum chamber 15). At this time, the control unit 103 detects that the sample mask unit fine movement mechanism 4 is mounted on the drive unit of the vacuum chamber 15.
Then, the user closes the sample stage drawing mechanism 60 and evacuates the vacuum chamber 15 with the evacuation system 6 to obtain a vacuum state.

<Specific machining area setting method when executing wide area milling>
Here, more specifically, a method of setting a machining area when performing wide area milling will be described. FIG. 20 is a diagram illustrating an exemplary arrangement of buttons for setting the target position in the control BOX 80. 21 and 22 are diagrams showing a specific example of a processing region setting method for wide region milling.

  When performing wide area milling, the user moves the sample 3 (sample mask unit 21) with the control BOX 80 (or the operation panel unit 80) while looking into the optical microscope 40 (or looking at the time) (L button in FIG. 20). 76 (left direction), R button 77 (right direction) is pressed), and both ends E1 and E2 of the region to be processed (processing range 2101) are set as shown in FIG. 21 (SET button 78 in FIG. 20 is pressed). To do.

  As shown in FIG. 21, the method of setting the processing region for the wide region milling may be set at both ends of the region to be processed, but as shown in FIG. 22, the center C1 of the region to be processed. May be set (processing range 2101). After setting, input a numerical value for the machining area on the operation unit 81 (or control BOX 80 (in this case, a function for inputting a numerical value for the machining area is added in addition to the button in FIG. 20), for example, a range of ± 2 mm from the center The setting range can be processed (sliding reciprocating drive) (see Fig. 24) The processing area of the wide area milling is either the both end position of the process or the center position of the process as shown in the operation screen of Fig. 23. It is possible to improve the operability by making it possible to select a machining area (milling) regardless of whether the machining area is set using “end position setting” or “center position setting”. ) The operation is the same.

  As shown in FIG. 20, the control BOX 80 is provided with a multi-point milling selection button and a wide area milling selection button so that either one or both can be selected.

<Machining procedure by wide area milling>
FIG. 24 is a diagram for explaining a processing procedure of the sample 3 by wide area milling.
When performing wide-area milling, the absolute irradiation position of the ion beam 2401 is fixed, and the specimen 3 is slid back and forth within the slide range 2403 by the slide movement mechanism (slide milling holder 70), thereby widening the wide area. A processed surface 2402 of the region is produced (see FIG. 24A).

  For this purpose, the slide moving mechanism moves the sample 3 from the center to the right end of the processing surface 2402 (see FIG. 24B) while irradiating the ion beam 2401, and further from the right end of the processing surface 2402 to the left end. Move the slide. While the sample 3 moves from the right end to the left end of the processing surface 2402, the ion beam 2401 is irradiated to the sample 3.

Subsequently, the slide moving mechanism slides the sample 3 from the left end to the right end of the processing surface 2402 (see FIG. 24C). While the sample 3 moves from the left end to the right end of the processing surface 2402, the ion beam 2401 is irradiated onto the sample 3.
The above slide movement operation is repeated until the end of processing (see FIGS. 24D and 24C).

<Reason why the slide moving mechanism is provided on the rotating body>
In the apparatus configuration described above, the slide moving mechanism (slide milling holder 70) is provided on the rotating body 9 (the sample stage 8 when the ion milling apparatus configuration of FIG. 1 is adopted). That is, the processing position of the reciprocating tilt axis and the sample upper surface is always the same. For this reason, even if the sample 3 is slid and driven while being reciprocally inclined, interference with a mechanism part (ion source 1, ion beam probe, etc.) in the sample chamber hardly occurs. Therefore, there are few restrictions on the slide range.

  FIG. 25 is a diagram showing the range of the reciprocating tilting operation of the sample during normal cross-section milling (a configuration in which the slide moving mechanism is not provided). FIG. 26 is a diagram showing the range of the slide movement operation and the reciprocating tilt operation when the slide movement mechanism (slide milling holder 70) is installed under the rotating body 9. FIG. FIG. 27 is a diagram showing the range of the slide movement operation and the reciprocating tilt operation when the slide movement mechanism (slide milling holder 70) is installed on the rotating body 9. FIG.

  In the case of normal section milling (FIG. 25), since the sample mask unit 21 does not slide, the position of the rotary tilt axis (rotary axis of the rotating body 9) 2502 is fixed, and the reciprocating tilt operation 2503 is performed within a fixed range. . Therefore, naturally, the sample mask unit 21 that performs the reciprocating tilting operation 2503 does not interfere with the ion beam probe 2501 and the ion source 1.

  On the other hand, as shown in FIG. 26, when the slide moving mechanism (slide milling holder 70) is installed under the rotating body 9, when the sample mask unit 21 slides, the position of the rotary tilt shaft 2502 also slides. Moving. Further, the sample mask unit 21 performs the reciprocating tilting operation 2503 while the rotary tilting shaft 2502 slides (the sliding direction 2601 is constant). Therefore, depending on the position of the rotary tilt axis 2502, the sample mask unit 21 interferes with the ion beam probe 2501 and the ion source 1 (interference portion 2602), and there is a high possibility that a sufficiently wide processing width cannot be obtained.

  Therefore, as shown in FIG. 27, a configuration is adopted in which the slide moving mechanism (slide milling holder 70) is installed on the rotating body 9. In this case, even if the sample mask unit 21 slides, the position of the rotation tilt shaft 2502 is fixed. Therefore, although the slide direction 2701 changes depending on the tilt angle of the reciprocating tilt operation 2503, the sample mask unit 21 does not interfere with the ion beam probe 2501 or the ion source 1 by the slide moving operation and the reciprocating tilt operation. For this reason, it becomes possible to make the slide width large at the time of a slide movement, and it becomes possible to obtain a wide processing width. If multipoint milling is performed with the configuration shown in FIG. 26, when machining a position away from the ion beam axis, the position of the rotary tilt axis 2502 changes as described above, so that the milling profile is not normal (milling profile). Is asymmetrical).

<Specific machining location setting method during multi-point milling>
Here, a method of setting a machining location when performing multi-point milling will be described more specifically. FIG. 28 is a diagram showing a specific example of a processing region setting method for multi-point milling.

  When performing multi-point milling (automatic machining at a plurality of locations), as in the case of wide area milling, while observing the optical microscope 40 (or peeking in a timely manner), the sample 3 (sample mask) is controlled by the control BOX 80 or the operation unit 81. The unit 21) is moved (L button 76 (left direction), R button 77 (right direction) is pressed). More specifically, as shown in FIG. 28 (when there are two machining locations), a plurality of positions P1 and P2 to be machined are set (the SET button 78 is pressed). Even when performing multi-point milling, it is desirable to fix the mask 2 so that the edge of the mask 2 is parallel to the direction of sliding movement.

  After setting the processing position, the motor cable (outside) 74 is removed from the slide milling holder 70, and the slide milling holder 70 is removed from the fixed base 42. Then, the slide milling holder 70 is mounted on the rotating body 9 or the sample unit base 5, and the motor cable (inner) 75 is connected to the slide milling holder 70.

  The sample stage drawing mechanism 60 is closed, and the vacuum chamber 15 is evacuated by the evacuation system 6 to be in a vacuum state. Further, argon gas is injected between the electrodes in the ion source 1, a high voltage is applied, and discharge is started. In this state, an acceleration voltage is applied, an ion beam is ejected, and processing is started (simultaneously reciprocating tilting).

<Processing by multi-point milling>
FIG. 29 is a diagram for explaining the processing procedure 1 of the sample 3 by multipoint milling. FIG. 30 is a diagram for explaining the processing procedure 2 for suppressing the occurrence of redeposition due to multi-point milling.

  As shown in FIG. 29 (when there are two machining locations), when machining at the first machining position 2901 (machining surface 2902) is completed, the slide milling holder 70 is automatically driven by the slide drive (X3 direction). Move to the second machining position 2904 (slide drive direction 2903) and start machining. If the third and subsequent locations have been selected, the same processing as described above is performed. By adopting the above processing method, multi-point milling (automatic processing at multiple locations) becomes possible.

  However, when machining is performed by this method, redeposition 3003 may occur on the surface of the first machining surface 3001 as shown in FIG. As a countermeasure, for example, when a processing time of 3 hours is set at each processing position, the processing position 2901 (first processing surface 3001) at the first position is processed for one hour (first time) → the second processing position 2904. Move to (second machining surface 3002), machining for 1 hour (first time) → move to first machining position 2901 (first machining surface 3001) again, machining for 1 hour (second time) → 2 Move to the machining position 2904 (second machining surface 3002) at the first position, machining 1 hour (second time) → move again to the machining position 2901 (first machining surface 3001) at the first location, and machining 1 hour (Third time) → Move to the second processing position 2904 (second processing surface 3002), perform processing one hour (third time), and complete the processing (in the case of FIG. 30B). The same applies to the case of FIG. 30C and FIG. In the case of the above-described processing method, since the time for one processing is short, the redeposition amount of the processing surface is greatly reduced. In addition, since the redeposition generated on the processed surface is cut during the next processing, a good cross section can be obtained. The machining method is set by dividing how many times the machining time for one place is divided or by inputting the time for division.

  Further, a processing method as shown in FIG. 30 (e) may be adopted. That is, for example, about 95% of the machining is completed at the first machining position 2901 (first machining surface 3001) (first time) and moved to the second machining position 2904 (second machining surface 3002). The machining at the second machining position 2904 (second machining surface 3002) is completed in one machining (for example, machining time 3 hours). Then, it moves again to the first processing position 2901 (first processing surface 3001), and the processing at the first processing position 2901 (first processing surface 3001) is completed. In this way, the machining time at the first machining position 2901 (first machining surface 3001) can be very shortened, so the second machining position 2904 (second machining surface 3002). The occurrence of redeposition 3003 can be greatly reduced.

  Further, a processing method as shown in FIG. 30 (f) may be employed. That is, the machining at the first machining position 2901 (first machining surface 3001) is completed once (for example, machining time 3 hours), and the second machining position 2904 (second machining surface 3002) is reached. It moves and is completed by one processing (for example, processing time 3 hours). Then, it moves again to the first machining position 2901 (first machining surface 3001), and finish machining is performed at the first machining position 2901 (first machining surface 3001) with a weaker acceleration voltage than during machining. . Furthermore, it moves again to the second processing position 2904 (second processing surface 3002) and finishes in the same manner. Thus, by performing the finishing process at the end, even if redeposition occurs at the processing position, it can be removed, and a desired process can be realized.

  When performing multi-point milling as described above (in the case of FIGS. 30B to 30F), each machining position is set, the number of machining times in each machining location, and the machining time in each machining. Is set.

  To summarize the multi-point milling as described above, a plurality of machining positions and the number of milling operations at each of the plurality of machining positions are set, and according to the information on each machining position and the number of milling operations at each machining position, the sample Each processing position in is processed. At that time, at least one milling operation in at least a part of the plurality of machining positions is alternately performed. That is, for example, as shown in FIGS. 30B to 30F, the milling operation is always performed alternately at each processing position. Further, at least one of the plurality of processing positions, a plurality of milling operations are performed with a time interval. That is, for example, in FIG. 30B, the first milling at the second machining position 3002 is performed after the first milling is performed at the first machining position 3001 and before the second milling is performed. . Further, the final stage of processing at each processing position is performed in order (see FIGS. 30B to 30D and 30F).

In the conventional ion milling apparatus, once processing at one place is completed, it is necessary to open the vacuum chamber to the atmosphere once, change the processing position, and then make the vacuum chamber vacuum again. On the other hand, in the ion milling apparatus according to the present embodiment, since processing at a plurality of locations (for example, 3 locations) is automatically performed, processing at a plurality of locations can be completed by a single process. Therefore, it is possible to easily obtain the optimum processing conditions for the sample to be processed. More specifically, multi-point milling can set respective machining conditions (discharge voltage, acceleration voltage, flow rate, reciprocating inclination angle, cooling temperature, etc.) at each machining position. This makes it easy to approach the optimal conditions. For example, the acceleration voltage at the first location is set to 2 kV, the acceleration voltage at the second location is set to 4 kV, and the acceleration voltage at the third location is set to 6 kV, and a certain sample is processed.
Further, by making it possible to select wide area milling at each processing position of multi-point milling, it is possible to apply to many applications.

<Utilization example of wide area milling>
FIG. 31 is a diagram showing an example of utilization of wide area milling. Here, a processing method in the case where the location where the processing is performed is not accurately known will be described. This processing method is effective when processing in a short time.

  Conventionally, as shown in FIG. 31A, when the position of an object to be processed (for example, a defect) is not known, there is no choice but to process the processing surface 3102 with an ion beam 3101 with a hit. However, this method may take too much time.

  Therefore, we will make use of processing by wide area milling to find and efficiently process what we want to process. Specifically, as shown in FIG. 31 (b), wide area milling (irradiating the beam while the sample 3 is reciprocally tilted and slid and driven) is performed. When the object (position) 3103 to be processed can be confirmed (optical microscope for processing observation (installed on the upper part of the processing observation window 7), the naked eye), the processing is stopped. Next, as shown in FIG. 31C, the sample holder is moved (slid) so that the ion beam axis is aligned with the position to be processed, and normal milling is performed.

  By this method combining wide area milling suitable for searching for a machining position and normal milling with a high milling rate, the machining time can be greatly reduced as compared with the case where wide area milling is performed to the end.

<Utilization example of multi-point milling>
FIGS. 32 to 34 are diagrams for explaining an application example of multi-point milling. FIG. 32 is a diagram for explaining a method of fixing a plurality of samples having different thicknesses. FIG. 33 shows a state in which a plurality of samples having different thicknesses are arranged and fixed to a mask. FIG. 34 is a diagram illustrating a state in which samples having different thicknesses are transferred to an observation apparatus and observed after processing.

  Here, as an application example of multi-point milling, a method of performing cross-sectional milling of a plurality of samples in one process will be described. In normal cross-section milling, the sample holder 23 to which the sample 3 is bonded is placed on the sample mask unit 21. When this sample fixing method is adopted, when different samples are adhered to the sample holder 23, if a sample having a different thickness is placed, a gap is formed between the mask 2 and the sample (thin one having the smaller thickness), and a smooth cross section cannot be obtained. .

  Therefore, as shown in FIGS. 32A to 32C, the sample is fixed by using the protrusion amount adjusting jig 90. First, the upper surface (ion beam irradiation side) of the mask 2 is brought into contact with the base 91 of the protrusion amount adjusting jig 90, and the mask 2 is fixed with the fixing screw 92. When the mask 2 is fixed, the wall on the right side of the base 91 is used so that the contact surface of the mask 2 and the position adjustment table 93 is parallel. The micrometer 94 is used to adjust the gap 3201 between the mask 2 and the position adjustment base 93 (moving along the linear guide). When the gap 3201 is enlarged, the micrometer 94 is rotated counterclockwise to provide the spring 95. It is structured to be pressed with pressure. After fixing the mask 2 to the base 91, the micrometer 94 is turned to bring the position adjusting table 93 into contact with the mask 2. The micrometer value (initial value) at that time is stored.

  Next, the micrometer 94 is rotated counterclockwise to adjust the gap 3201 between the mask 2 and the position adjustment table 93. Since the distance of the gap 3201 (which will be described later, the amount of protrusion and equal) is a value obtained by subtracting the current value and the initial value of the micrometer 94, it can be adjusted to an arbitrary value. After the distance of the gap 3201 is determined, the sample 3 is brought into contact with the position adjustment base as shown in FIG. 32C, the fixing position is determined, and the sample 3 is directly adhered to the mask 2 (on the ion beam irradiation side of the sample 3). The surface of is brought into contact with the mask 2). When the sample is bonded in this manner, the distance of the gap 3201 becomes equal to the protrusion amount 3301. Further, since the sample 3 can be directly fixed to the mask, a plurality of samples having different thicknesses can be arranged and fixed. Although not shown, the protruding amount 3301 of the sample 3 can be varied (see FIG. 33).

  After the fixing (adhesion) of all the samples to the mask 2 is completed, the fixing screws are loosened, and the mask 2 to which the samples are fixed is removed from the protrusion amount adjusting jig. The mask 2 is fixed to the mask holder 25 (sample mask unit 21) using a mask fixing screw 27. By adopting the above fixing method and multi-point milling (adjustment of X and Y (X3 and Y3 in FIG. 8 (where X3 is a motor drive) in FIG. 8) of the sample mask unit fine movement mechanism 4 has been described above). A plurality of samples can be performed by one milling process.

  After the plurality of samples fixed to the mask 2 are processed, the mask 2 is removed from the ion milling apparatus and attached to the sample mounting table 105 of the observation apparatus (SEM) (see FIG. 34). The sample mounting table 105 has a structure in which the mask 2 can be fixed with a fixing screw 106, and the mask 2 with the sample 3 fixed can be easily fixed to the sample mounting table 105.

  Further, an internal thread portion (in the case where the screw portion 3402 is provided on the sample fixing base 107 side of the observation apparatus) 3401 is provided on the bottom surface of the sample mounting base 105, and the screw portion of the sample fixing base 107 of the observation apparatus is provided. It is possible to fix to 3402. Therefore, the mask 2 on which the sample 3 is fixed can be easily installed in the observation apparatus and observed. As for the position of the internal thread portion 3401 of the sample mounting base 105, it is desirable that the processing surface be arranged on the central axis of the external thread portion 3402 so that the processing surface can be easily found during observation.

<Modification>
(I) In the ion milling apparatus shown in FIGS. 1 and 10, the sample mask unit fine movement mechanism 4 on which the sample mask unit 21 is mounted is detachable from the sample unit base 5. However, even when the sample mask unit fine movement mechanism 4 mounted with the sample unit base 5 and the sample mask unit 21 is integrated, the same processing can be performed by mounting the optical microscope 40 on the apparatus side. In this case, the motor cable (outside) 74 and the motor cable (inside) 75 and the slide milling holder 70 are not inserted or removed, but there is a possibility that the space for adjusting the position is limited. is there.

(Ii) In the present embodiment, the ion milling apparatus and the observation apparatus (SEM) have been described on the assumption that they are configured separately, but they may be configured as an integral unit. In this case, for example, the sample unit base 5 and the sample mask unit 21 are shared, and a mechanism for switching between an ion source used for ion milling and an electron gun used for observing the processed surface is provided. Since information (position information) of a processing location is held in the control unit 103 during ion milling, the information can be used also in an observation apparatus, and control such as alignment during observation is facilitated. There is an advantage. In addition, since it is possible to save the trouble of taking the processed sample from the ion milling apparatus and installing it in the observation apparatus, it is possible to improve the throughput from the processing to the observation.

<Summary>
(I) In the wide area milling process, a wide machining width independent of the ion beam diameter can be obtained by simultaneously performing a reciprocating tilting operation and a sliding operation during ion beam irradiation. Therefore, it is effective for samples that require a wide range of observation and analysis. Further, in multi-point milling, after completion of cross-sectional milling (reciprocating tilting operation during ion beam irradiation), the multi-point milling can be slid to a preset processing position (several) and further cross-sectional milling can be performed at that position. . Therefore, machining at a plurality of positions can be performed automatically, and throughput can be improved.

  The ion milling apparatus according to the present embodiment has a sample slide moving mechanism that slides the sample holder in a direction including the normal direction component of the ion beam axis. The ion milling device may further include a rotation mechanism that rotates and tilts the sample holding unit around an axis perpendicular to the direction of slide movement by the sample slide movement mechanism. In this case, a slide movement mechanism (motor drive) is disposed above the rotation mechanism (a mechanism in which the reciprocating tilt (rotation) axis does not move even when a slide operation is performed), and the position of the rotation axis of the rotation mechanism may not move. desirable. Moreover, it is preferable that the rotating shaft of the rotating mechanism exists on the trajectory of the ion beam. Further, it is desirable that the slide movement mechanism slides the sample in a plane perpendicular to the rotation axis of the rotation mechanism. This makes it possible to perform a reciprocal sliding operation (sliding operation with a width wider than the ion beam width) in addition to reciprocating and tilting the sample while performing ion beam irradiation (normal cross-section milling). By the processing method, a desired processing width is obtained in one process (wide area milling). Since the processing width of the wide area milling is not limited by the ion beam width, a wide processing surface (observation surface) can be obtained.

  In addition, the slide moving mechanism is used to automatically move (slide) to the next processing position after completion of the cross-section milling, and perform cross-section milling again at the moved position. With this processing method, it is possible to automatically perform cross-sectional milling at multiple locations (multi-point milling). In multi-point milling, cross-section milling at a plurality of locations can be performed in a single process, so that throughput can be improved.

(Ii) The ion milling apparatus according to the present embodiment includes an ion source that emits an ion beam, a sample holding unit that holds a sample, and a sample that slides the sample holding unit in a direction that includes a normal direction component of the ion beam axis. A slide moving mechanism and a control unit; The control unit controls the sample slide movement mechanism based on the processing information input regarding the processing content of the sample, and performs wide area milling for processing the sample into a wider area than the width of the ion beam, and / or a plurality of samples. Enables multi-point milling to machine this part. By doing so, it is possible to automatically execute wide area milling and multi-point milling with one ion milling device. It is also possible to execute a combination of wide area milling and multi-point milling.

(Iii) The ion milling apparatus according to the present embodiment can select at least one of wide area milling for processing a sample into a wider area than the width of the ion beam and multi-point milling for processing a plurality of locations on the sample. And a control unit that controls a milling operation on the sample based on a selection input to the user interface unit. As a result, the user can efficiently execute a desired milling operation by selecting one of wide-area milling and multi-point milling, or by combining the two.

  When both wide area milling and multipoint milling are selected, the control unit controls the milling operation while switching the operation between wide area milling and multipoint milling. As a result, wide area milling and multi-point milling can be performed efficiently in a single process.

(Iv) In this embodiment, when performing ion milling, first, a sample is placed on an optical microscope, and the optical microscope is used to process a wide region in the sample to be wider than the width of the ion beam. A processing position and processing width of milling, and a plurality of processing positions of multi-point milling for processing a plurality of portions of the sample are set. Next, information on the processing position and processing width of wide area milling and information on a plurality of processing positions of multi-point milling are transmitted to a control unit that controls the milling operation. And a sample is removed from an optical microscope and the said sample is installed in an ion milling apparatus. The control unit controls a milling operation in the ion milling apparatus based on information on the processing position and processing width of the wide area milling and information on a plurality of processing positions of multi-point milling. Through the above operations, wide area milling and multipoint milling are performed. By doing so, it is possible to efficiently execute wide area milling and multi-point milling automatically and in a single process. The same procedure is performed when only wide area milling or multipoint milling is executed.

(V) Multi-point milling may be performed in the following procedure. First, a plurality of machining positions when performing multi-point milling and the number of milling operations at the plurality of machining positions are set. Next, the plurality of processing positions of the sample are processed according to the set information on the plurality of processing positions and the set number of milling operations. At that time, at least one milling operation at least in a part of the plurality of machining positions is alternately performed, and at least one machining position of the plurality of machining positions is performed a plurality of times at intervals. Like that. When the milling operation is performed with a time interval, the milling operation is performed at another machining position during the idle time. As a result, redeposition that may occur at each processing position can be greatly reduced.

  Further, the final stage of processing (final milling operation) at a plurality of processing positions may be performed in order. Thus, by performing the last slight machining at each machining position in order, the occurrence of redeposition at each machining position can be suppressed to a very low level.

  Furthermore, finishing may be performed at a plurality of machining positions with an acceleration voltage that is weaker than the acceleration voltage used when machining alternately. Even if it does in this way, generation | occurrence | production of redeposition can be suppressed similarly.

(Vi) According to the present embodiment, the following milling process can be executed. First, wide area milling is performed on the specimen to process it into a wider area than the width of the ion beam, and a processing location is searched. And the processing location discovered by the wide area milling is milled in the depth direction of the sample. In this way, it is possible to efficiently find a difficult-to-find location by wide area milling, and then mill the location intensively. Thus, throughput can be improved.

(Vii) According to the present embodiment, milling may be performed in the following procedure. First, a plurality of samples are attached to the sample mask so that a predetermined amount protrudes from the sample mask. Next, each processing position in a plurality of samples is set. Then, the sample beam is irradiated with an ion beam from the side of the sample mask, multi-point milling for processing a plurality of portions of the sample is executed, and each of the plurality of samples is processed. In this case, the plurality of samples may include samples whose sample thickness is different from that of other samples. By doing in this way, it becomes possible to mill the sample from which thickness differs by one process. Further, it is possible to avoid a risk that a gap is generated between the sample and the mask due to the difference in thickness of the sample, and redeposition occurs due to the ion beam wrapping around the gap.

1 ion source, 2 mask, 3 sample, 4 sample mask unit fine movement mechanism, 5 sample unit base, 6 vacuum exhaust system, 7 processing observation window, 8 sample stage, 9 rotating body, 10 flange, 11, 24 linear guide, 12 Loupe, 13 Loupe fine movement mechanism, 15 Vacuum chamber, 21 Sample mask unit, 22 Sample holder rotating ring, 23 Sample holder, 25 Mask holder, 26 Mask fine adjustment mechanism, 27 Mask fixing screw, 28 Sample holder rotating screw, 29 Reverse rotation Spring, 30 Sample holder position control mechanism, 35 Sample holder fixing bracket, 40 Optical microscope, 41 Observation table, 42 Fixing table, 50 Gear, 51 Bearing, 52 Mask unit fixing part, 53 Shaft coupling, 54 Linear motion device, 55 Motor , 60 Specimen stage drawing mechanism, 70 Slide milling machine Luda, 71 X Gear, 72 Motor Unit, 73 M Gear, 74 Motor Cable (Outside), 75 Motor Cable (Inside), 76 L Button, 77 R Button, 78 SET Button, 80 Control Box, 81 Operation Unit, 90 Projection amount adjusting jig, 91 base, 92 fixing screw, 93 position adjusting table, 94 micrometer, 95 spring, 100 ion milling device, 101 shutter, 102 optical microscope side driver, 103 control unit 104 vacuum chamber side driver, 105 Sample mounting table, 106 fixing screw, 107 Sample fixing table, 2101, processing range, 2401 ion beam, 2402 processing surface, 2403 slide range, 2501 ion beam measuring element, 2502 rotary tilt axis, 2503 reciprocating tilting operation, 2601 slide direction, 602 Interference location, 2701 Slide direction, 2901 First machining position, 2902 Processing surface, 2903 Slide drive direction, 2904 Second machining position, 3001 First machining surface 3001, 3002 Second machining position, 3003 Rede Position, 3101 Ion beam, 3102 Processing surface, 3103 Object to be processed, 3201 Clearance, 3301 Projection amount, 3401 Internal thread, 3402 External thread, 3501 Motor unit, 3502 Motor unit

Claims (3)

An ion milling method that uses an ion milling apparatus to irradiate a sample at least partially shielded by a mask with an ion beam and process the sample,
Performing a wide area milling to process the sample to a wider area than the width of the ion beam, searching for a processing location,
Milling the processed spot discovered by the wide area milling in the depth direction of the sample;
An ion milling method comprising: An ion milling method that uses an ion milling apparatus to irradiate a sample at least partially shielded by a mask with an ion beam and process the sample,
Attaching a plurality of samples to the sample mask so that a predetermined amount protrudes from the sample mask;
Setting each processing position in the plurality of samples;
Irradiating the sample with the ion beam from the side of the sample mask, performing multi-point milling to process a plurality of locations of the sample, and processing each of the plurality of samples;
An ion milling method. In claim 2,
The ion milling method, wherein the plurality of samples includes a sample having a sample thickness different from that of other samples.