JP6828095B2 - Ion milling method - Google Patents

Description

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

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

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

On the other hand, ion milling can process even soft samples without crushing the surface morphology, and can polish hard samples and composite materials. In addition, there is an effect that a cross section in a mirror surface state can be easily obtained. For example, Patent Document 1 discloses an ion milling apparatus capable of reducing the amount of streaky irregularities formed on a processed surface by irradiating an ion beam while inclining or rotating a sample.

Japanese Unexamined Patent Publication No. 2014-139938

As a result of diligent studies by the inventor of the present application on a processing method for cross-section milling, the following findings have been obtained.

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

However, when machining is required for a machining width (observation width) larger than the ion beam width or for multiple machining points, the sample chamber is opened to the atmosphere, the machining position is changed, the sample chamber is evacuated again, and additional machining is performed. There is a need. Such additional machining reduces the throughput.

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

In order to solve the above problems, the present disclosure is an ion milling method for processing a sample by irradiating a sample at least partially shielded with a mask with an ion beam using an ion milling device. On the other hand, performing wide-area milling to process a wider area than the width of the ion beam to search for the processing site, and milling the processed area found by wide-area milling in the depth direction of the sample. We propose an ion milling method including.

Further features relating to this disclosure will become apparent from the description herein and the accompanying drawings. In addition, the aspects of the present disclosure are achieved and realized by the combination of elements and various elements, the detailed description below, and the aspects of the appended claims.
It should be understood that the description herein is merely a exemplary example and is not intended to limit the claims or applications of the present 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 21. It is a figure for demonstrating the method of making a cross section of a sample parallel with a mask. It is a figure which shows the structure of the sample stage pull-out mechanism 60. It is a figure which shows the structural example of the optical microscope 40 which observes the shielding positional relationship between a mask 2 and a sample 3. 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 fixing base 42. It is a figure for demonstrating the method of aligning the part which wants to polish the cross section of a sample 3 with the center of an ion beam. It is a figure for demonstrating the method of mirror polishing the cross section of a sample 3 with an ion beam. It is a figure which shows the configuration example 2 of the ion milling apparatus by this Embodiment which has a structure different from the configuration example 1 and enables both cross-section 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 on the ion milling apparatus shown in FIG. It is a figure for demonstrating the rotation mechanism which rotates the mask unit fixing part 52 provided in the sample unit base 5. It is a figure which shows the rotation mechanism which rotates a mask unit fixing part 52 by rotating a shaft joint 53. It is a figure which shows the state which the sample mask unit fine movement mechanism 4 is installed in the optical microscope 40 for processing position adjustment. It is a figure which shows the structural example of the rotation tilting mechanism, more specifically, is the figure which shows the structure of the part A surrounded by the dotted line of FIG. It is a figure which shows the mechanism for rotating a rotating body 9 by a shaft joint. It is a figure which shows the structural example of the slide milling holder (slide movement mechanism) 70 for sliding movement of a sample mask unit fine movement mechanism 4 in the X-axis direction. It is a figure which shows the connection relationship between devices at the time of setting a processing position of ion milling. It is a flowchart for demonstrating the procedure of the processing position setting process. It is a figure which shows the arrangement example of the button for setting a target position in a control BOX 80. 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 operation screen example of the processing area setting in wide area milling. It is a figure for demonstrating the processing procedure of the sample 3 by wide area milling. It is a figure which shows 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. It is a figure which shows the state of rotation and slide movement of the sample mask unit 21 in the case where the slide movement mechanism (slide milling holder 70) is installed under the rotating body 9. It is a figure which shows 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. It is a figure which shows the specific example of the processing area setting method of multipoint milling. It is a figure for demonstrating the processing procedure 1 of the sample 3 by multi-point milling. It is a figure for demonstrating the machining procedure 2 for suppressing the occurrence of redeposition by multipoint milling. It is a figure which shows an example of utilization of wide area milling. It is a figure for demonstrating the method of fixing a plurality of samples having different thicknesses. It is a figure which shows the state in which a plurality of samples having different thicknesses are arranged and fixed to a mask. It is a figure which shows the state of moving a sample of a different thickness to an observation apparatus after processing and observing. It is a figure which shows the connection relationship between the apparatus at the time of setting a processing position of ion milling by a modification. It is a flowchart for demonstrating the procedure of the processing position setting process by a modification.

In general, when processing is required for a processing width (observation width) larger than the ion beam width or for multiple processing points, the sample chamber is opened to the atmosphere, the processing position is changed, the sample chamber is evacuated again, and then additional processing is performed. There is a need. Such additional machining reduces the throughput. In addition, there is a high possibility that redeposition will occur on the first machined surface.

Therefore, in the present embodiment, a machined surface having a desired width (wider than the ion beam width) is generated on the sample without generating redeposition by ion milling as much as possible while improving the 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 make it possible to generate a machined surface having a desired width in one machined process and generate a plurality of machined points.

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

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

The sample mask unit fine movement mechanism 4 is mounted on the sample unit base 5. The mounting is performed by bringing the lower surface of the sample mask unit fine movement mechanism 4 (the side facing the mask surface irradiated with the ion beam) into contact with the upper surface of the sample unit base 5 and fixing them with screws. The sample unit base 5 is configured to be rotationally tilted at an arbitrary angle with respect to the optical axis of the ion beam, and the direction and tilt angle to be rotationally tilted are controlled by the sample stage 8. By rotating and tilting the sample stage 8, the sample 3 installed 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 inclination axis of the sample stage 8 and the upper surface of the sample (lower surface of the mask) are aligned with each other to efficiently produce a smooth processed surface. Further, the sample mask unit fine movement mechanism 4 is configured to be movable in the front-back and left-right directions in the direction perpendicular to the optical axis of the ion beam, that is, in the X direction and the Y direction.

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. The sample unit base 5 is configured to be pulled out of the vacuum chamber 15 when the vacuum chamber 15 is opened to the atmospheric state. In this way, the sample stage withdrawal mechanism is configured.

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

The sample mask unit 21 has a mechanism for finely adjusting the position and rotation angle of the mask, and can be attached to and removed 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 are composed of two parts, but may be composed of one part (in the embodiment, the sample mask unit and the sample mask unit are for easy understanding. The fine movement mechanism will be explained separately).

The mask 2 is fixed to the mask holder 25 by the mask fixing screw 27. The mask holder 25 moves along the linear guide 24 by operating the mask fine adjustment mechanism (that is, the mask position adjustment unit) 26, whereby the positions of the sample 3 and the mask 2 are finely adjusted. The sample holder 23 is inserted into and fixed to the sample holder rotating ring 22 from the lower side. The sample 3 is adhesively fixed to the sample holder 23 (for example, adhesively fixed with carbon paste, white wax, double-sided tape, or the like). 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 showing another configuration example of the sample mask unit 21. In the configuration example, the sample holder fixing bracket 35 for holding the sample holder 23 is used, and the other configurations are 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 the sample holder 23 to which the sample 3 is fixed 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 parallel to the mask. The sample holder rotary screw 28 is turned to adjust the position in the X1 direction, and fine adjustment is made under a microscope so that the cross section of the sample 3 and the ridgeline of the mask 2 are parallel to each other as described later. At this time, the mask fine adjustment mechanism 26 is rotated so that the cross section of the sample 3 protrudes slightly from the mask, for example, about 50 μm.

FIG. 5 is a diagram showing the configuration of the sample stage withdrawal mechanism 60. The sample stage drawing mechanism 60 includes a linear guide 11 and a flange 10 fixed to the linear guide 11, and the sample unit base 5 fixed to the sample stage mounted on the flange 10 is pulled out from the vacuum chamber 15 along the linear guide 11. Is done. Along 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 integrally pulled out from the vacuum chamber 15.

In the present embodiment, the sample mask unit fine movement mechanism 4 in which the sample mask unit 21 is installed has a structure that is detachably fixed to the sample unit base 5. Therefore, when the sample mask unit fine movement mechanism 4 in which the sample mask unit 21 is installed is pulled out to the outside of the vacuum chamber 15, the sample mask unit fine movement mechanism 4 in which the sample mask unit 21 is installed is in a detachable state from the sample unit base 5. (Standby for attaching / detaching the sample mask unit 21).

FIG. 5 is a diagram showing a state in which the sample mask unit fine movement mechanism 4 on which the sample mask unit 21 is installed is attached / detached from such a detachable state. This attachment / detachment can be performed manually or with a suitable instrument.

FIG. 6 is a diagram showing a configuration example of an optical microscope 40 for observing 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 place. The optical microscope 40 includes a well-known loupe 12 and a loupe fine movement mechanism 13. Further, the optical microscope 40 is provided with a fixing base 42 for mounting the sample mask unit fine movement mechanism 4 in which the sample mask unit 21 removed on the observation table 41 is installed. Then, the sample mask unit fine movement mechanism 4 in which the sample mask unit 21 is installed is installed at a fixed position on the fixing base 42 with reproducibility by a positioning shaft and a hole.

FIG. 7 is a diagram showing a state in which the sample mask unit fine movement mechanism 4 on which the sample mask unit 21 is installed is fixed on the fixing base 42. In this way, after the sample mask unit fine movement mechanism 4 on which the sample mask unit 21 is installed is fixed on the fixing base 42, the portion to be polished in cross section of the sample by the method described with reference to FIG. 8 is centered on the ion beam (FIG. Match with "+") in 8.

FIG. 8 is a diagram for explaining a method of aligning the 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 marks formed by irradiating the sample holder 23, that is, the center of the ion beam and the center of the loupe are aligned by driving X2 and Y2 with the loupe fine movement mechanism 13. As a result, the center of the ion beam 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, copper foil, or the like 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 mounting the sample 3 is installed is installed on the fixing base 42. By adjusting the positions of the sample mask unit fine movement mechanism 4 in the X3 and Y3 directions and aligning the portion to be cross-section polished with the center of the loupe, the center of the ion beam and the portion to be cross-section polished can be aligned. In this way, 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 removed from the sample unit base 5 and mounted on the fixing base 42 of the optical microscope 40. Then, the mask 2 has a shielding positional relationship with respect to the sample 3 adjusted by the mask position adjusting 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. By irradiating with an argon ion beam, 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.

In this way, the sample mask unit fine movement mechanism 4 provided with the sample mask unit 21 provided with the mask 2 whose shielding positional relationship with respect to the sample is adjusted during ion milling is returned to the sample unit base 5 and mounted.

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 removed from the sample unit base 5 and mounted on the fixing base 42 of the optical microscope 40. , The sample mask unit fine movement mechanism 4 provided with the sample mask unit 21 provided with the mask 2 in which the shielding positional relationship with respect to the sample is adjusted and the shielding positional relationship with respect to the sample is adjusted during ion milling is installed in the vacuum chamber 15. An ion milling method is configured in which the sample unit is returned and mounted on 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 that of the configuration example 1 and enables both cross-section milling and plane milling.

The ion milling device 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 the right side surface) of the vacuum chamber 15, and an ion source. It was mounted on the flange 10 provided on the side surface different from the side surface provided with 1, 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 the 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 above the box (in an environment with gravity, in a gravitational field). 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 equipped with the sample mask unit 21 is provided with the mask unit fixing portion 52. There is. Further, the method of fixing the sample holder 23 is different from the configuration of FIG. That is, the sample holder 23 is adapted 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 diagram for explaining a rotation mechanism for rotating the mask unit fixing portion 52 provided on the sample unit base 5. The sample unit base 5 is provided with a rotating body 9 on which a sample holding member (a member for holding a sample including the sample mask unit fine movement mechanism 4) can be placed. The rotating body 9 functions as a support base for supporting the sample holding member. The sample unit base 5 is composed of a rotating body 9, a gear 50, and a bearing 51. The sample mask unit fine movement mechanism 4 is mounted by bringing the fixed 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 and fixing the sample mask unit with screws from the mask unit fixing portion 52. The sample unit base 5 does not rotate and tilt, and the rotating body 9 mounted on the sample unit base 5 can rotate and tilt the sample unit base 5 at an arbitrary angle with respect to the optical axis of the ion beam emitted from the side surface direction of the vacuum chamber 15. It is configured, and the direction of rotational tilt and the tilt angle are controlled by the sample stage 8.

Here, as a method of rotationally tilting the rotating body 9 of the sample unit base 5, a method of rotating the sample stage 8 as shown in FIG. 12 and a method of rotating the shaft joint 53 as shown in FIG. 13 are used. However, either one may be used. By rotationally tilting the rotating body 9 of the sample unit base 5, the sample 3 installed 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 upper surface of the sample (lower surface of the mask) are aligned with each other to produce an efficient and smooth processed surface.

FIG. 14 is a diagram showing a state in which the sample mask unit fine movement mechanism 4 is installed in the optical microscope 40 for adjusting the processing position. The device and the optical microscope 40 may be installed separately from the device by using the lower surface of the sample mask unit fine movement mechanism 4 without using the mask unit fixing portion 52. The difference between FIG. 14 and FIG. 6 is that the loupe fine movement mechanism 13 for adjusting the beam center and the loupe center is performed on the fixed base 42 side. As the loupe fine movement mechanism 13, either this example or the example of FIG. 6 may be adopted. Other than that, the same work as in the example of FIG. 6 is performed.

FIG. 15 is a diagram showing a configuration example of the rotation tilting mechanism, and more specifically, a diagram showing a configuration of a portion A surrounded by a dotted line in FIG. As illustrated in FIG. 15, the ion milling apparatus according to the configuration example 2 (FIG. 10) is provided with a rotation function in the rotation inclination mechanism of the sample and an inclination mechanism having a rotation inclination axis in the direction perpendicular to the ion beam axis. Has been done. The rotary tilt mechanism rotates the rotating body 9 (not shown in FIG. 15) via the shaft and the gear 50 by the rotational force of the motor 55. By doing so, it is possible to realize an eccentric mechanism that shifts the ion beam axis and the rotation axis of the sample mask unit fine movement mechanism 4 when the inclination angle is 90 degrees. As shown in FIG. 16, a method using a shaft joint may also be used. However, when a shaft joint is used, it is desirable to install it in the rotating inclined portion as shown in FIG. 16 and to install the eccentric mechanism (movement in the Y-axis direction) 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 to perform cross-section milling (the sample is milled through a mask to obtain a smooth surface). Plane milling (processing a plane perpendicular to the ion beam axis (at an inclination angle of 90 degrees of the sample stage) to be smooth) is possible.

<Slide movement mechanism for realizing wide area milling and multipoint 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 processing a region on a sample having a width wider than the ion beam width. Further, multi-point milling means processing a plurality of points on the sample (particularly, in the present embodiment, the plurality of points are automatically processed).

The ion milling device 100 capable of both wide-area milling and multi-point milling is provided with a slide moving mechanism (also referred to as a slide drive mechanism) capable of moving (sliding) in a direction perpendicular to the optical axis of the ion beam, and is vacuum. It is necessary to slide the sample mask unit 21 in the chamber. It is desirable that the direction of slide movement and the edge of the mask 2 have a parallel relationship. Further, it is desirable that the position of the rotation tilt axis does not move even if 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 device, the following configuration is desirable. In this embodiment, the case where the motor, which is the drive source in the X-axis direction, is installed in the vacuum chamber (when the motor is driven) will be described, but it may be installed outside the chamber.

In order to perform wide area milling and multipoint milling, it is desirable to be able to drive the sample mask unit fine movement mechanism 4 in the X-axis direction (see FIG. 10) in the vacuum chamber 15 in addition to the configuration shown in FIG. .. Specifically, by using a motor as a drive source in the X direction of the sample mask unit fine movement mechanism 4, it is possible to drive in the X direction in the vacuum chamber 15.

FIG. 17 is a diagram showing a configuration example of a slide milling holder (slide movement 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 a drive shaft in the X-axis direction of the sample mask unit fine movement mechanism 4. Further, the motor unit 72 is installed on the lower surface side of the sample mask unit fine movement mechanism 4. The motor unit 72 is composed of a motor, an M gear 73, a cover, and the like, and the M gear 73 (it does not have to be directly attached to the rotating shaft of the motor. The final via a plurality of gears) is attached to the rotating shaft of the motor. A step (a 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 integrated type or a separate type, but are described here as a separate type. In the separate type, even if the motor unit 72 is removed, normal cross-section 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 while 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 via 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. With the above configuration, it is possible to realize an ion milling device that does not move the rotation tilt axis while sliding. The slide milling holder 70 is arranged above the rotating body 9 in the ion milling apparatus shown in FIGS. 10 and 12. Further, the slide milling holder 70 is placed on the sample unit base 5 in the ion milling apparatus shown in FIG.

<Processing content from setting the machining target position to the start of machining>
FIG. 18 is a diagram showing a connection relationship between devices when setting a processing position for ion milling. FIG. 19 is a flowchart for explaining the procedure of the machining position setting process. With reference to FIGS. 18 and 19, an ion milling operation method using the slide milling holder 70 in which the sample mask unit fine movement mechanism 4 in which the sample mask unit 21 is installed and the motor unit 72 are combined (sample 3 is the sample mask unit 21). Operation from the state where it is installed in) will be described. The power supply for driving the motor is supplied from the main body control unit 103 of the ion milling device 100 via the motor cable (outside) 74 and the 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 machining position setting process is started, the control unit 103 executes the 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 the arrow button provided on the operation unit (for example, the touch panel) 81 or the control BOX (for example, separated from the control unit 103 and installed near the optical microscope 40) 80. , The slide milling holder 70 on which the sample 3 is mounted is moved to a target position (position to be processed) (X-axis direction: X3 in FIG. 8), and the enter button provided on the control BOX 80 or the like is pressed. The movement in the X-axis direction is driven by a motor. The adjustments other than the X-axis movement are the same as the operation method described in FIG. When the movement is made in the X-axis direction, the control unit 103 provides information on the target position (information on the number of pulses corresponding to the number of times the arrow button is pressed to move the slide milling holder 70 to the target position). get. The target position can also be set numerically (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 information on the target position (distance from the origin: the number of pulses generated when moving to the target position) acquired in step 1903, and stores the information in the memory (not shown) in the control unit 103. ).

(V) Step 1905
When the user completes the setting of the target position using the optical microscope 40, 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 fixing 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. Place it on (in the case of the ion milling device configuration of FIG. 1). Then, the user connects the motor cable (inside) 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 (inside) 75.
Then, the user closes the sample stage extraction mechanism 60 and exhausts the inside of the vacuum chamber 15 with the vacuum exhaust system 6 to put the sample in a vacuum state.

(Vii) Step 1907
The control unit 103 executes the 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 device is moved.

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

(Viii) Step 1908
The control unit 103 reads out the information of 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 of FIG. 10) or the sample stage 8 (in the case of the configuration example of the ion milling apparatus of FIG. 1) is reciprocally tilted at an arbitrary angle, and By performing the slide reciprocating drive of the slide milling holder 70 (see FIG. 24), it is possible to obtain a machined surface in a wide area. (The range of the slide reciprocating drive is between the positions set under the optical microscope 40.) The slide reciprocating drive may be continuous or intermittent. As an example of intermittent drive, it is conceivable to set a 0.1 mm slide after 10 seconds machining → ... → 0.1 mm slide after 10 seconds machining, and input the stop (machining) time and slide distance. Be done.

<Processing content from machining target position setting to machining start (transformation example)>
FIG. 35 is a diagram showing a connection relationship between devices when setting a processing position of ion milling according to a modified example. FIG. 36 is a flowchart for explaining the procedure of the machining position setting process according to the modified example. With reference to FIGS. 35 and 36, an operation method of ion milling using the sample mask unit fine movement mechanism 4 in which the sample mask unit 21 is installed (operation from the state where the sample 3 is installed in the sample mask unit 21) 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), but in the modified example, the vacuum chamber 15 side. A drive unit (including a motor) is provided on each of the and the optical microscope 40 side. Therefore, 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 in which the sample mask unit 21 is installed may be moved back and forth between the vacuum chamber 15 and the optical microscope 40, and at this time, it is not necessary to connect / disconnect the cable. In the machining position setting processing procedure shown in FIG. 36, step 3601, step 3602, and step 3603 are executed instead of steps 1901, 1905, and 1906 in FIG. In the following, only steps 3601 to 3603 different from those in FIG. 19 will be described.

(I) Step 3601
The user (operator) mounts the sample mask unit fine movement mechanism 4 on the optical microscope 40 having the 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. Therefore, unlike step 1901 in FIG. 19, the connection step of the motor cable (outside) is unnecessary (only the sample mask unit fine movement mechanism 4 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 has been 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 (inside) 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 connection step of the motor cable (inside) is unnecessary (only the sample mask unit fine movement mechanism 4 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 extraction mechanism 60 and exhausts the inside of the vacuum chamber 15 with the vacuum exhaust system 6 to put the sample in a vacuum state.

<Specific machining area setting method when performing 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 showing an example of arranging buttons for setting a target position in the control BOX 80. 21 and 22 are diagrams showing a specific example of a processing area setting method for wide area 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 timely time) (L button in FIG. 20). 76 (left direction), press the R button 77 (right direction)), and set both ends E1 and E2 of the area (machining range 2101) to be machined as shown in FIG. 21 (press the SET button 78 in FIG. 20). To do.

As a method of setting the machining area of the wide area milling, as shown in FIG. 21, both ends of the area to be machined may be set, but as shown in FIG. 22, the center C1 of the area to be machined is set. May be set (machining range 2101). After setting, enter the machining area numerically on the operation unit 81 (or control BOX80 (in this case, a function that allows numerical input of the machining area is added in addition to the button in FIG. 20), for example, a range of ± 2 mm from the center. It is set so that the set range can be machined (slide reciprocating drive) (see FIG. 24). The machining area of wide area milling is either the both end position of machining or the center position of machining as shown in the operation screen of FIG. The operability can be improved by making it possible to select. Machining processing (milling) regardless of whether the machining area is set by using "setting of both end positions" or by using "setting of center position". ) 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, and one or both of them can be selected.

<Processing procedure by wide area milling>
FIG. 24 is a diagram for explaining a processing procedure of the sample 3 by wide area milling.
When the wide area milling process is performed, the absolute irradiation position of the ion beam 2401 is fixed, and the sample 3 is slid back and forth within the slide range 2403 by the slide moving mechanism (slide milling holder 70). The machined surface 2402 of the region will be produced (see FIG. 24 (a)).

Therefore, in the state of irradiating the ion beam 2401, the slide moving mechanism moves the sample 3 from the center to the right end of the machined surface 2402 (see FIG. 24B), and further moves from the right end to the left end of the machined surface 2402. Move the slide. The ion beam 2401 irradiates the sample 3 while the sample 3 moves from the right end to the left end of the machined surface 2402.

Subsequently, the slide moving mechanism slides the sample 3 from the left end to the right end of the machined surface 2402 (see FIG. 24 (c)). The ion beam 2401 irradiates the sample 3 while the sample 3 moves from the left end to the right end of the machined surface 2402.
The above slide movement operation is repeated until the end of machining (see FIGS. 24 (d) and 24 (c)).

<Reason why the slide movement mechanism is provided on the rotating body>
In the device configuration described above, a slide moving mechanism (slide milling holder 70) is provided on the rotating body 9 (sample stage 8 when the ion milling device configuration of FIG. 1 is adopted). That is, the reciprocating tilt axis and the processing position on the upper surface of the sample are always the same. Therefore, even if the sample 3 is slid-driven while being tilted back and forth, interference with the mechanical parts (ion source 1, ion beam transducer, etc.) in the sample chamber is unlikely to occur. Therefore, there are few restrictions on the slide range.

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

In the case of normal cross-section milling (FIG. 25), since the sample mask unit 21 does not slide and move, the position of the rotation tilt axis (rotation 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 transducer 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 rotating tilt shaft 2502 also slides. Moving. Further, the sample mask unit 21 performs a reciprocating tilting operation 2503 while the rotation tilting shaft 2502 slides (the slide direction 2601 is constant). Therefore, depending on the position of the rotation tilt axis 2502, the sample mask unit 21 may interfere with the ion beam transducer 2501 and the ion source 1 (interference point 2602), and there is a high possibility that a sufficiently wide processing width cannot be obtained.

Therefore, as shown in FIG. 27, the slide moving mechanism (slide milling holder 70) is installed on the rotating body 9. In this case, the position of the rotary tilt shaft 2502 is fixed even if the sample mask unit 21 slides and moves. Therefore, although the slide direction 2701 changes depending on the tilt angle of the reciprocating tilting operation 2503, the sample mask unit 21 does not interfere with the ion beam transducer 2501 or the ion source 1 due to the sliding moving motion and the reciprocating tilting motion. Therefore, it is possible to obtain a large slide width when the slide is moved, and it is possible to obtain a wide processing width. When multi-point milling is performed with the configuration shown in FIG. 26, the position of the rotation tilt axis 2502 changes as described above when processing a position away from the ion beam axis, so that the milling profile becomes abnormal (milling profile). Is asymmetrical).

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

When performing multi-point milling (automatic processing at multiple locations), as in the case of wide-area milling, while looking into the optical microscope 40 (or looking at it in a timely manner), sample 3 (sample mask) is used in the control BOX 80 or the operation unit 81. The unit 21) is moved (the L button 76 (leftward) and the R button 77 (rightward) are pressed). More specifically, as shown in FIG. 28 (when there are two machining points), a plurality of positions P1 and P2 to be machined are set (press the SET button 78). Even when performing multipoint milling, it is desirable to fix the edges of the mask 2 so that they are parallel to the direction of slide movement.

After setting the machining position, the motor cable (outside) 74 is removed from the slide milling holder 70, and the slide milling holder 70 is removed from the fixing 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 (inside) 75 is connected to the slide milling holder 70.

The sample stage extraction mechanism 60 is closed, and the inside of the vacuum chamber 15 is exhausted by the vacuum exhaust system 6 to create a vacuum state. Further, argon gas is injected between the electrodes in the ion source 1 and a high voltage is applied to start the discharge. In that state, an acceleration voltage is applied, an ion beam is emitted, and processing is started (at the same time, reciprocating inclination is performed).

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

As shown in FIG. 29 (when there are two machining points), when the machining (machining surface 2902) at the first machining position 2901 is completed, the slide milling holder 70 is automatically driven by the slide drive (X3 direction). It moves to the second machining position 2904 (slide drive direction 2903) and starts machining. If the third and subsequent locations are selected, the same processing as 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 machined surface 3001 as shown in FIG. 30A. As a countermeasure, for example, when machining 3 hours are set at each machining position, machining 1 hour (first time) at the first machining position 2901 (first machining surface 3001) → second machining position 2904. Moved to (second machined surface 3002), machined 1 hour (first time) → moved to the first machined position 2901 (first machined surface 3001) again, machined 1 hour (second time) → 2 Move to the machining position 2904 (second machining surface 3002) of the first place and move to the first machining position 2901 (first machining surface 3001) for 1 hour (second time) → 1 hour of machining. (Third time) → Move to the second processing position 2904 (second processing surface 3002), perform processing for one hour (third time), and complete the processing (in the case of FIG. 30B). The same applies to the cases of FIGS. 30 (c) and 30 (d). In the case of the above processing method, the redeposition amount of the processed surface is significantly reduced because one processing time is short. In addition, since the redeposition generated on the machined surface is scraped during the next machining, a good cross section can be obtained. The processing method is set by dividing the processing time at one location into several times or by inputting the division time.

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 the process is 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, the machining time is 3 hours). Then, the machine moves to the first machining position 2901 (first machining surface 3001) again, and the machining at the first machining position 2901 (first machining surface 3001) is completed. By doing so, the machining time at the first machining position 2901 (first machining surface 3001) can be very shortened, so that the machining time at the second machining position 2904 (second machining surface 3002) can be shortened. The occurrence of redeposition 3003 can be greatly reduced.

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

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

Summarizing the above-mentioned multi-point milling, the number of milling operations at a plurality of machining positions and the plurality of machining positions is set, and a sample is set according to the information of each machining position and the number of milling operations at each machining position. Each machining position in is machined. At that time, at least one milling operation at at least a part of the plurality of processing positions is alternately performed. That is, for example, as shown in FIGS. 30 (b) to 30 (f), the milling operation is always alternately executed once at each processing position. Further, at at least one machining position of the plurality of machining positions, a plurality of milling operations are performed at intervals. That is, for example, in FIG. 30B, the first milling at the second machining position 3002 is performed after the execution of the first milling at the first machining position 3001 and before the execution of the second milling. .. Further, the final stage machining at each machining position is performed in order (see FIGS. 30 (b) to (d) and (f)).

In the conventional ion milling apparatus, once the machining at one location is completed, it is necessary to open the vacuum chamber to the atmosphere once, change the machining position, and then evacuate the vacuum chamber again. On the other hand, in the ion milling apparatus according to the present embodiment, since the processing at a plurality of locations (for example, three locations) is automatically performed, the processing at a plurality of locations can be completed by one processing. Therefore, it is possible to easily obtain the optimum processing conditions for the sample to be processed. More specifically, in multipoint milling, each machining condition (discharge voltage, acceleration voltage, flow rate, reciprocating tilt angle, cooling temperature, etc.) can be set at each machining position. This facilitates the approach to 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.
In addition, by making it possible to select wide area milling at each processing position of multipoint milling, it is possible to apply it to many applications.

<Example of using wide area milling>
FIG. 31 is a diagram showing an example of utilization of wide area milling. Here, a processing method will be described when the location to be processed is not known exactly. This processing method is effective when processing is performed in a short time.

Conventionally, as shown in FIG. 31 (a), when the position of an object to be processed (for example, a defect) is unknown, there is no choice but to make a hit and process the processed surface 3102 with an ion beam 3101. However, such a method may take too much time.

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

By the method that combines wide area milling suitable for finding a processing position and normal milling with a high milling rate, it is possible to significantly reduce the processing time as compared with the case of wide area milling to the end.

<Example of using multi-point milling>
FIGS. 32 to 34 are diagrams for explaining an example of utilization of multipoint milling. FIG. 32 is a diagram for explaining a method of fixing a plurality of samples having different thicknesses. FIG. 33 is a diagram showing a state in which a plurality of samples having different thicknesses are arranged and fixed to a mask. FIG. 34 is a diagram showing a state in which samples having different thicknesses are transferred to an observation device after processing and observed.

Here, as an example of utilization 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 adhered is installed in the sample mask unit 21. When the sample fixing method is adopted, when different samples are adhered to the sample holder 23, when samples having different thicknesses are placed, a gap is formed between the mask 2 and the sample (thinner one), and a smooth cross section cannot be obtained. ..

Therefore, as shown in FIGS. 32 (a) to 32 (c), 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 by the fixing screw 92. When fixing the mask 2, the wall on the right side of the base 91 is used so that the contact surfaces of the mask 2 and the position adjusting table 93 are parallel to each other. A micrometer 94 is used to adjust the gap 3201 between the mask 2 and the position adjustment table 93 (moving along the linear guide). To increase the gap 3201, the micrometer 94 is turned counterclockwise and the spring 95 It has a structure that pushes with pressure. After fixing the mask 2 to the base 91, the micrometer 94 is turned to bring the position adjustment table 93 into contact with the mask 2. The value (initial value) of the micrometer at that time is stored.

Next, the micrometer 94 is turned counterclockwise to adjust the gap 3201 between the mask 2 and the position adjustment table 93. Since the distance of the gap 3201 (described later, equal to the protrusion amount) 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 fixed position is determined while the sample 3 is in contact with the position adjustment table as shown in FIG. 32 (c), and the sample 3 is directly adhered to the mask 2 (ion beam irradiation side of the sample 3). The surface of the surface is brought into contact with the mask 2.). When the samples are adhered in this way, the distance of the gap 3201 is equal to the protrusion amount 3301. Further, since the sample 3 can be directly fixed to the mask, it is possible to arrange and fix a plurality of samples having different thicknesses. Although not shown, the protrusion amount 3301 of the sample 3 can be different from each other (see FIG. 33).

After fixing (adhering) all the samples to the mask 2 is completed, loosen the fixing screws and remove the mask 2 fixing the samples from the protrusion amount adjusting jig. The mask 2 is fixed to the mask holder 25 (sample mask unit 21) using the mask fixing screw 27. By adopting the above fixing method and multi-point milling (X and Y of the sample mask unit fine movement mechanism 4 (X3 and Y3 in FIG. 8 (however, X3 is driven by a motor)) are omitted because they are described above). , It is possible to perform a plurality of samples in one milling process.

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

Further, a female screw portion (when the screw portion 3402 is provided on the sample fixing base 107 side of the observation device) 3401 is provided on the bottom surface of the sample setting base 105, and the screw portion of the sample fixing base 107 of the observation device is provided. It is possible to fix it to 3402. Therefore, the mask 2 to which the sample 3 is fixed can be easily installed in the observation device and observed. It is desirable that the position of the female threaded portion 3401 of the sample setting table 105 is such that the machined surface is arranged on the central axis of the male threaded portion 3402 so that the machined surface can be easily found during observation.

<Modification example>
(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 can be attached and detached from the sample unit base 5. However, even when the sample mask unit fine movement mechanism 4 on which the sample unit base 5 and the sample mask unit 21 are mounted is integrated, the same processing can be performed by mounting the optical microscope 40 on the device side. In this case, the work of inserting and removing the motor cable (outside) 74, the motor cable (inside) 75, and the slide milling holder 70 is eliminated, but the space for performing work such as adjusting the position may be limited. is there.

(Ii) In the present embodiment, the ion milling device and the observation device (SEM) have been described on the premise that they have separate device configurations, but these may be configured as one. In this case, for example, the sample unit base 5 and the sample mask unit 21 are shared, and a mechanism for switching between the ion source used for ion milling processing and the electron gun used for observing the processed surface is provided. Since the information (position information) of the processed portion is held in the control unit 103 during the ion milling process, the information can also be used by the observation device, and it becomes easy to control the alignment and the like during the observation. There is an advantage. Further, since it is possible to save the trouble of taking out the processed sample from the ion milling device and further installing it in the observation device, it is possible to improve the throughput from processing to observation.

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

The ion milling apparatus according to the present embodiment has a sample slide moving mechanism for sliding the sample holding portion in a direction including a normal component of the axis of the ion beam. Further, the ion milling device may further have a rotation mechanism for rotating and tilting the sample holding portion 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 placed above the rotation mechanism (a mechanism in which the reciprocating tilt (rotation) axis does not move even when the slide operation is performed), and the position of the rotation axis of the rotation mechanism does not move. desirable. Further, the rotation axis of the rotation mechanism preferably exists in the orbit of the ion beam. Further, it is desirable that the slide moving mechanism slides the sample in a plane perpendicular to the rotation axis of the rotating mechanism. As a result, in addition to the reciprocating tilting operation of the sample (normal cross-section milling) while irradiating the ion beam, the reciprocating sliding operation (sliding operation with a width wider than the ion beam width) can be performed. By the processing method, a desired processing width can be obtained by one processing (wide area milling). Since the processing width of wide-area milling is not limited to the ion beam width, it is possible to obtain a wide range of processed surfaces (observation surfaces).

In addition, the slide movement mechanism is used to automatically move (slide) to the next machining position after the cross-section milling is completed, and the cross-section milling is performed again at the moved position. With this processing method, it is possible to automatically perform cross-section milling at a plurality of 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) In the ion milling apparatus according to the present embodiment, the ion source that emits an ion beam, the sample holding portion that holds the sample, and the sample that slides the sample holding portion in the direction including the normal component of the axis of the ion beam. It has 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 processes the sample into a wider area than the width of the ion beam, and / or a plurality of samples. It enables multi-point milling to process the parts of. By doing so, it becomes possible to automatically perform wide area milling and multipoint milling by one ion milling device. It is also possible to perform a combination of wide area milling and multipoint milling.

(Iii) The ion milling apparatus according to the present embodiment can select at least one of wide region milling for processing a sample into a wider area than the width of an ion beam and multipoint milling for processing a plurality of parts of a sample. It has a user interface unit for controlling the sample and a control unit for controlling the milling operation with respect to the sample based on the selection input to the user interface unit. This allows the user to efficiently perform the desired milling operation by selecting one of the wide area milling and the multipoint 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. This makes it possible to efficiently perform wide area milling and multipoint milling in one process.

(Iv) In the present embodiment, when performing ion milling, first, a sample is placed in an optical microscope, and the sample is processed into a wider area than the width of the ion beam by using the optical microscope. Set the machining position and width of the milling, and multiple machining positions of the multipoint milling to machine multiple points of the sample. Next, information on the machining position and machining width of wide area milling and information on a plurality of machining positions of multipoint milling are transmitted to a control unit that controls the milling operation. Then, the sample is removed from the optical microscope and the sample is placed in the ion milling apparatus. The control unit controls the milling operation in the ion milling device based on the information on the machining position and machining width of the wide area milling and the information on the plurality of machining positions of the multipoint milling. By the above operation, wide area milling and multipoint milling are executed. By doing so, it becomes possible to efficiently execute wide area milling and multipoint milling by automatic and one-time processing. The procedure is the same when performing wide area milling or multipoint milling only.

(V) Multi-point milling may be performed according to 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 is alternately performed at at least a part of the plurality of machining positions, and a plurality of milling operations are performed at at least one machining position of the plurality of machining positions at intervals. To do so. When the milling operation is performed after a certain period of time, the milling operation at another processing position is performed in the free time. This makes it possible to greatly reduce the redeposition that may occur at each machining position.

Further, the final stage machining (final milling operation) at a plurality of machining positions may be performed in order. By sequentially performing the last slight machining at each machining position in this way, the occurrence of redeposition at each machining position can be suppressed to a very small extent.

Further, the finish machining may be performed at a plurality of machining positions with an acceleration voltage weaker than the acceleration voltage used when machining alternately. Even in this way, the occurrence of redeposition can be suppressed in the same manner.

(Vi) According to the present embodiment, the following milling process can be performed. First, a wide area milling is performed on the sample to process the sample in a wider area than the width of the ion beam, and the processing location is searched for. Then, the processed portion found by wide area milling is milled in the depth direction of the sample. By doing so, it becomes possible to efficiently find a difficult-to-find part by wide area milling and then intensively mill the part. Therefore, it is possible to improve the throughput.

(Vii) According to the present embodiment, the milling process may be performed by the following procedure. First, a plurality of samples are attached to the sample mask so as to protrude from the sample mask by a predetermined amount. Next, each processing position in a plurality of samples is set. Then, the sample is irradiated with an ion beam from the side of the sample mask, multipoint milling is performed to process a plurality of parts of the sample, and the plurality of samples are processed respectively. In this case, the plurality of samples may include a sample having a sample thickness different from that of the other samples. By doing so, samples having different thicknesses can be milled in one treatment. Further, it is possible to avoid the risk that a gap is generated between the sample and the mask due to the difference in the thickness of the sample, and the redeposition is generated 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 Machining 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 rotation ring, 23 Sample holder, 25 Mask holder, 26 Mask fine adjustment mechanism, 27 Mask fixing screw, 28 Sample holder rotation 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 gears, 51 bearings, 52 mask unit fixing part, 53 shaft joints, 54 linear motion equipment, 55 motors , 60 sample stage pull-out mechanism, 70 slide milling holder, 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 part, 90 protrusion amount adjustment jig, 91 base, 92 fixing screw, 93 position adjustment base, 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 Machining range, 2401 Ion beam, 2402 Machining surface, 2403 Slide range, 2501 Ion beam stylus, 2502 Rotating tilt axis, 2503 Reciprocating tilt operation, 2601 slide direction, 2602 interference point, 2701 slide direction, 2901 1st machined position, 2902 machined surface, 2903 slide drive direction, 2904 2nd machined position, 3001 1st machined surface 3001, 3002 2nd machining position, 3003 redeposition, 3101 ion beam, 3102 machining surface, 3103 object to be machined, 3201 gap, 3301 protrusion amount, 3401 female thread part, 3402 male thread part, 3501 motor unit, 3502 motor unit

Claims (1)

An ion milling method in which a sample that is at least partially shielded by a mask is irradiated with an ion beam to process the sample using an ion milling device.
To search for a processing site by performing wide area milling on the sample to process it in a wider area than the width of the ion beam.
Milling the processed portion found by the wide area milling in the depth direction of the sample, and
Ion milling method including.