JP6675121B2 - Sample holding / scanning mechanism, scanning probe microscope, and method of manufacturing probe - Google Patents

Description

  The present invention provides a sample holding / scanning mechanism capable of obtaining a three-dimensional stereoscopic image of a sample with a high degree of freedom of freedom by eliminating the adverse effects of a substrate conventionally used for fixing a sample, and a scanning type equipped with the sample holding / scanning mechanism. The present invention relates to a method for manufacturing a probe used in a probe microscope and a sample holding / scanning mechanism.

Structural analysis of various samples is performed using a scanning probe microscope (SPM).
A scanning probe microscope is a general term for a device that scans a probe relative to a sample to obtain information such as the shape and properties of the sample. For example, an atomic force microscope (AFM) , An optical displacement sensor for detecting the displacement of the cantilever, and a scanner for relatively scanning the probe and the sample.
Then, while scanning the probe relatively in the XY direction (horizontal direction of the substrate) with respect to the sample on the substrate by the scanner, the Z direction of the probe (substrate of the substrate) is maintained so that the output of the optical displacement sensor is kept constant. The vertical position) is controlled, and an image of the sample surface is obtained by mapping the position.
In recent years, the development of a scanning probe microscope aiming at obtaining a three-dimensional stereoscopic image of a sample has been advanced.For example, for a three-dimensional sample fixed on a flat substrate, one probe is attached to the substrate surface. Images are acquired by tilting the probe in two directions, forward and reverse, respectively, and a three-dimensional image is obtained by combining these two images and an image acquired without tilting the probe, for a total of three images. Are known (Non-Patent Documents 1 and 2).

“New three-dimensional AFM for CD measurement and sidewall characterization”, Proc. SPIE 7971, Metrology, Inspection, and Process Control for Microlithography XXV, 797118 (April 20, 2011) “Three-dimensional imaging of undercut and sidewall structures by atomic force microscopy”, Review of Scientific Instruments Volume 82, Issue 2, 023707 (February 2011)

However, the conventional method for acquiring a three-dimensional stereoscopic image of a sample as described above has the following problems.
That is, when the sample is soft, the sample fixed on the flat substrate spreads in a plane direction due to a strong action such as an attractive force from the substrate, and there is a problem that the three-dimensional shape is broken.
In addition, since only the front side of the substrate can be scanned, there is a problem that when the contact area between the sample and the substrate is large, an image of the contacted portion cannot be obtained.
As described above, the conventional method has a problem in that the degree of spatial freedom at the time of image acquisition is greatly limited by the presence of the substrate.

  In view of such a problem, the present invention eliminates the adverse effects of a substrate conventionally used for fixing a sample, and a sample holding / scanning mechanism capable of acquiring a three-dimensional stereoscopic image of a sample with a high degree of spatial freedom. It is an object of the present invention to provide a scanning probe microscope having a mechanism and a method for manufacturing a probe used in a sample holding / scanning mechanism.

The sample holding / scanning mechanism of the present invention includes an X-axis direction probe set composed of two probes arranged oppositely along the X-axis direction, and two probes arranged oppositely along the Y-axis direction. Y-axis direction probe set to be performed, a Z-axis direction probe set composed of two probes arranged facing each other along the Z-axis direction, and each of the six probes is driven at least in the XYZ-axis direction. One driving mechanism is provided, and one or more probes hold a sample, and another probe scans the sample three-dimensionally in the XYZ axis directions.
In addition, a total of one probe of the X-axis direction probe set, one of the Y-axis direction probe sets, and one of the Z-axis direction probe sets is counted. In a state where the sample is held at three points by the three probes, another probe scans the sample three-dimensionally in the XYZ axis directions.
Further, the six driving mechanisms are mounted on a gimbal having three degrees of freedom of rotation.
Further, among the six drive mechanisms, a drive mechanism for driving the probe used for holding the sample is characterized in that the drive mechanism is separately attached to the gimbal without being attached to the gimbal.
Also, one or two of the X-axis direction probe set, the Y-axis direction probe set, and the Z-axis direction probe set are removed, and one of the remaining probe sets is used. The drive mechanism provided on the other opposing probe is attached to a gimbal having three degrees of freedom of rotation, and the other opposing probe scans the sample three-dimensionally in the XYZ axis directions. Features.
Further, regarding the probe used for holding the sample, the sample is fixed to the probe.
The apparatus further comprises the sample holding / scanning mechanism, and further obtains a three-dimensional three-dimensional image of the sample by complementarily synthesizing an image obtained by three-dimensionally scanning the sample with the other probe. It is characterized by comprising an image synthesizing means.
In the method for manufacturing a probe used for the sample holding / scanning mechanism, the step of fixing both ends of a columnar member serving as a probe material to the driving mechanism may include cutting the columnar member from both ends toward the center in the longitudinal direction. The method includes a step of performing a taper process to reduce an area, and a step of manufacturing the two opposed probes by separating the columnar member into two at the minimum position of the cross-sectional area.

Since the sample holding / scanning mechanism of the present invention holds the sample at a point using a probe, the present invention can solve various problems that the three-dimensional shape of the conventional case where the sample is placed on the substrate is lost. A three-dimensional stereoscopic image can be obtained in a state close to the actual three-dimensional shape with a high degree of spatial freedom without being affected by the above.
In particular, if three points are used to hold the sample at three points, the sample can be held reliably, and a clear three-dimensional stereoscopic image can be obtained.
In addition, if the six drive mechanisms are mounted on a gimbal that has three degrees of freedom of rotation, the probe that is not holding the sample can be moved around the sample, further increasing the degree of spatial freedom. it can.
In addition, if the drive mechanism for driving the probe for holding the sample is not attached to the gimbal and is separately supported, the probe not used for holding the sample is used for holding the sample that is arranged to face the sample. Since the probe can be moved independently of the probe, the probe can be moved to an arbitrary position of approximately 360 ° around the sample, and the degree of freedom of image acquisition can be further improved.
Further, if two opposing probes are simultaneously manufactured by processing a columnar member serving as a probe material, the positioning operation of the two probes can be simplified and the operation efficiency can be improved.

FIG. 2 is a perspective view illustrating an appearance of a sample holding / scanning mechanism according to the first embodiment. FIG. 2 is a plan view illustrating an appearance of a sample holding / scanning mechanism according to the first embodiment. FIG. 2 is a block diagram illustrating a structure of a sample holding / scanning mechanism according to the first embodiment. FIG. 9 is a perspective view illustrating an appearance of a sample holding / scanning mechanism according to a second embodiment. FIG. 4 is a plan view illustrating an appearance of a sample holding / scanning mechanism according to a second embodiment. FIG. 4 is a block diagram illustrating a structure of a sample holding / scanning mechanism according to a second embodiment. Perspective view from above showing the appearance of a sample holding / scanning mechanism according to a third embodiment. FIG. 9 is a perspective view from below showing an appearance of a sample holding / scanning mechanism according to a third embodiment. FIG. 9 is a plan view illustrating an appearance of a sample holding / scanning mechanism according to a third embodiment. FIG. 9 is a block diagram illustrating a structure of a sample holding / scanning mechanism according to a third embodiment. Diagram showing manufacturing method of probe

[First Embodiment]
A first embodiment of a sample holding / scanning mechanism according to the present invention will be described with reference to the drawings. The sample holding / scanning mechanism of the present invention can be used for a general scanning probe microscope, and the detailed description of the operation principle of the scanning probe microscope is omitted because it is well known.
As shown in FIGS. 1 and 2, the sample holding / scanning mechanism 1 includes an X-axis direction probe set 10, a Y-axis direction probe set 20, a Z-axis direction probe set 30, and a drive mechanism 40.
The X-axis direction probe set 10 is composed of two probes 11 and 12 arranged facing each other along the X-axis direction.
Specifically, each of the probes 11 and 12 has a conical shape, one of the probes 11 extends so as to reduce its cross-sectional area along the positive direction of the X axis, and the other Along the negative direction of the axis, the cross-sectional area extends so as to reduce the diameter. Thus, the two probes are arranged such that the sharp portions at the tips thereof face each other with the sample S interposed therebetween.
The Y-axis direction probe set 20 is composed of two probes 21 and 22 arranged facing each other along the Y-axis direction.
Specifically, each of the probes 21 and 22 has a conical shape, one of the probes 21 extends so as to reduce its cross-sectional area along the positive direction of the Y axis, and the other of the probes 22 has a Y shape. Along the negative direction of the axis, the cross-sectional area extends so as to reduce the diameter. Thus, the two probes 21 and 22 are arranged so that the sharp portions at the tips thereof face each other with the sample S interposed therebetween.
The Z-axis direction probe set 30 is composed of two probes 31 and 32 arranged facing each other along the Z-axis direction.
Specifically, each of the probes 31 and 32 has a conical shape, one of the probes 31 extends so as to reduce its cross-sectional area along the positive direction of the Z axis, and the other of the probes 32 has a Z shape. Along the negative direction of the axis, the cross-sectional area extends so as to reduce the diameter. Thus, the two probes 31 and 32 are arranged such that the sharp portions at the tips thereof face each other with the sample S interposed therebetween.

One drive mechanism 40 is provided for each probe in order to drive each of the six probes at least in the XYZ axis directions.
Hereinafter, as an example, a description will be given of the drive mechanism 40 attached to the probe 11 whose cross-sectional area is reduced in diameter along the positive direction of the X-axis. As shown in FIG. 1 (b), the drive mechanism 40 includes a cylindrical main body 41 whose longitudinal direction extends along the X axis. One piezoelectric element 42 is provided at a position penetrating the Z axis, and one piezoelectric element 44 is provided at the rear end of the main body 41. The drive control of the probe by the piezoelectric element is a well-known technique, and thus detailed description is omitted.However, the displacement of the piezoelectric elements 41 to 44 is controlled by controlling the voltage applied to the piezoelectric elements 41 to 44 provided in the main body 41. By adjusting the amount, the probe 11 is moved in three XYZ axes. Further, in this case, the cylindrical main body 41 is attached to a coarse movement mechanism (see FIG. 2) so as to be able to largely move in both positive and negative directions of the X axis.
Each drive mechanism 40 is attached to a frame 50 formed by assembling three square frames 51, 52, 53 extending in an XY plane, a YZ plane, and a ZX plane into a cubic shape.

In the present embodiment, the sample S is held at three points by three of the six probes 11, 21, and 31, and the sample S is three-dimensionally moved in the XYZ axis directions by the other three probes 12, 22, and 32. Original scan.
Specifically, three probes 11, 21, 31 extending so that the cross-sectional area decreases in the positive direction of the XYZ axes are used, and these three probes 11, 21, 31 are fixed to the sample S. Thus, three points of the sample S are held. As a method for fixing the probes 11, 21, and 31 to the sample, a known technique such as a welding method using an electron beam or a bonding method using a carbide may be used.

FIG. 3 is a block diagram schematically showing a configuration when a scanning probe microscope 2 including a sample holding / scanning mechanism 1 according to the present embodiment is incorporated in an electron microscope 3.
The six drive mechanisms 40 are connected to controllers 100 for fine movement control and coarse movement control, respectively, and these controllers 100 operate based on drive signals output from the CPU 101. As described above, the sample S is held at three points by the three probes 11, 21, and 31, and the surface of the sample S is three-dimensionally scanned in the XYZ axis directions by the other three probes 12, 22, and 32, and the probe is searched. The signal of the needle-sample interaction (eg, tunnel current, atomic force, electrostatic force, near field, magnetic force, exchange force, chemical bonding force, etc.) is detected by a signal detector. Then, a three-dimensional image of the sample is obtained by complementarily combining the three sets of images obtained independently from each other by the CPU 101 as the image synthesizing means.
Note that the three probes 11, 21, and 31 used for holding the sample may be kept stationary without being driven by the drive mechanism 40, but if the three probes 11, 21, and 31 are moved, the sample S is moved to the sample S. It is possible to acquire a three-dimensional stereoscopic image in a state where external forces such as tension, compression, and shear are applied. In addition, if a current is supplied to the sample S via the probes 11, 21, and 31, a three-dimensional stereoscopic image of the sample S in the energized state can be obtained.
The acquired 3D image contains not only information about the geometric structure of the sample S but also information about mechanical, electrical, and chemical properties. It can be used in various research fields such as the development of electronic devices having a three-dimensional structure in which the structure and physical properties are closely related, drug development, and drug delivery.
As described above, in the sample holding / scanning mechanism 1 according to the present embodiment, the sample S is held at a point (tip of the probe). Therefore, conventionally, when the sample is placed on the substrate, the sample has a strong attractive force from the substrate. There was a problem that the three-dimensional shape collapsed due to the action, and the three-dimensional shape collapsed, and a problem that the lower surface of the sample was hidden by the substrate. The sample S can be observed in the state.
In addition, by incorporating the scanning probe microscope 2 into the electron microscope 3 alone or into an electron microscope equipped with a focused ion beam generator, not only can the observation of the sample S by the electron microscope 3 be performed, but also as described later, There is also an advantage that an electron beam or even an ion beam can be used when manufacturing a probe.
In the present embodiment, the sample S is held by the three probes 11, 21, 31. However, the present invention is not limited to this, and the sample S may be held by one or more probes. For example, when holding with one probe, scanning may be performed with all the remaining five probes, or scanning may be performed with four or less probes.
In this embodiment, the probe is fixed to the sample S. However, the probe is not necessarily fixed, and the probe may be held in contact with the sample.

[Second embodiment]
Next, a second embodiment of the sample holding / scanning mechanism of the present invention will be described with reference to the drawings, and portions having the same configuration as the above embodiment will be denoted by the same reference numerals and will not be described. Is omitted.
The present embodiment is characterized in that six drive mechanisms 40 are mounted on a gimbal 60 having three degrees of freedom of rotation as shown in FIGS.
Specifically, the gimbal 60 is supported by a large-diameter ring 61 that is rotatably supported by the frame 50 so as to be rotatable around the X axis, and a large-diameter ring 61 that is rotatable around the Y axis. And a small-diameter ring 63 supported by the medium-diameter ring 62 so as to be rotatable around the Z axis. The X-axis direction probe set 10 is a small-diameter ring 63, the Y-axis direction probe set 20 is a large-diameter and medium-diameter ring 61,62, and the Z-axis direction probe set 30 is a medium-diameter and small-diameter ring 62, By attaching it to 63, the other three probes 12, 22, 32 not used for holding the sample can be moved around the sample S. The rotational drive of each ring 61, 62, 63 is controlled by a controller 100 for coarse movement control.
In this embodiment, the gimbal 60 having three degrees of freedom of rotation is used, but a gimbal having two degrees of freedom of rotation may be used.
Also, remove one or two of the X-axis probe set, Y-axis probe set, and Z-axis probe set, and use one of the tips that make up the remaining probe set. Holding the drive mechanism of the other opposing probe to a gimbal having three degrees of freedom of rotation, and the other opposing probe performs three-dimensional scanning of the sample in the XYZ axis directions. Good.

[Third Embodiment]
Next, a third embodiment of the sample holding / scanning mechanism of the present invention will be described with reference to the drawings, and portions having the same configuration as the above embodiment will be denoted by the same reference numerals and will not be described. Is omitted.
In the present embodiment, as shown in FIGS. 7 to 10, regarding the drive mechanism 40 for driving the probes 11, 21, 31 used for holding the sample, these drive mechanisms 40 are not attached to the gimbal 60, and the support member 70 is used. It is characterized by being separately supported.
This makes it possible to move the other three probes 12, 22, and 32 that are not used for holding the sample to an arbitrary position around the sample S at substantially 360 °. In other words, in the case of the configuration of the second embodiment, for example, the probe 12 that is not used for holding the sample in the X-axis direction probe set 10 is the probe that is used for holding the sample that is disposed to face the sample. Since the probe 11 moves integrally with the probe 11, the probe 11 cannot move to the vicinity of the location holding the sample S, and to acquire an image of the location, the Y-axis direction probe set 20 or the Z-axis It was necessary to move the probes 22, 32 of the directional probe set 30 to the relevant location. However, according to the configuration of the present embodiment, the probes 11, 21, and 31 used for holding the sample are supported by the support member 70 and are not incorporated in the gimbal 60. Therefore, the probes 12, 22, 32 that are not used for holding the sample can move independently of the probes 11, 21, 31 that are used for holding the sample that is arranged opposite thereto, and for example, the X-axis direction probe An image of the vicinity of the holding position of the sample S and the probe 11 used for holding the sample in the set 10 can be acquired by the probe 12 not used for holding the sample, thereby improving the degree of freedom in image acquisition. Can be.

Next, a method of manufacturing a probe used for a sample holding / scanning mechanism will be described.
This manufacturing method includes a first step of fixing both ends of a columnar member 80 to be a probe material to the drive mechanism 40 as shown in FIG. 11 (a), and the columnar member 80 as shown in FIG. 11 (b). A second step of tapering so that the cross-sectional area decreases from both ends toward the center in the longitudinal direction, and by separating the columnar member 80 into two at the minimum position of the cross-sectional area as shown in FIG. The method further includes at least a third step of manufacturing two probes (for example, the probe 11 and the probe 12) disposed to face each other.
In this way, it is better to apply processing to one columnar member 80 having both ends fixed to the drive mechanism 40 and dispose the two probes facing each other, after fixing two separately manufactured probes to the drive mechanism 40, The working efficiency can be improved as compared with the case where the drive mechanism 40 is operated to position the two probes so as to face each other.
As a method of performing taper processing so that the cross-sectional area decreases from both ends of the columnar member 80 toward the center in the longitudinal direction, for example, electron beam processing with an electron beam can be mentioned, but as described in the first embodiment. Furthermore, if the scanning probe microscope is incorporated in the electron microscope, there is an advantage that electron beam processing can be performed using an electron gun provided in the electron microscope. In addition, it is necessary to adjust the shape of the probe in accordance with the shape and properties of the sample from which a three-dimensional stereoscopic image is to be obtained. Work efficiency can be improved. There is also an advantage that the state and position of each probe can be monitored using the function of the electron microscope at the time of manufacturing the probe and acquiring an image.
It is not always necessary to incorporate the scanning probe microscope 2 into the electron microscope 3, and an electron beam of a known processing machine other than the electron microscope may be used, or a known processing method such as a focused ion beam may be used. .

Next, a flow from the manufacture of the probe to the acquisition of an image when the scanning probe microscope 2 is incorporated in the electron microscope 3 will be described.
First, the columnar member 80 serving as a probe material is fixed to the drive mechanism 40, and the sample holding / scanning mechanism 1 is introduced into the electron microscope 3. Then, the columnar member 80 is processed using an electron beam so that the two probes face each other. The same operation is repeated to manufacture the other two sets of tips.
Next, in a state where the sample S is held at three points by the three probes 11, 21, and 31, the sample S is irradiated with an electron beam to produce a clean sample. Then, the other three probes 12, 22, and 32 are moved to obtain three sets of images, and these images are complementarily combined by the image combining means (CPU 101) to obtain a three-dimensional stereoscopic image.
Next, by moving the probes 11, 21, 31 used for holding the sample as needed, or by applying an electrical (magnetic) signal or the like to the probes 11, 21, 31, the sample S To obtain a three-dimensional image in a state where external force, electric (magnetic) signal, and the like are added to the image.
Then, after returning the probes 12, 22, and 32 not used for holding the sample to the predetermined position, the sample holding / scanning mechanism 1 is removed from the electron microscope 3 and the process is terminated.

  The present invention relates to a sample holding / scanning mechanism capable of acquiring a three-dimensional stereoscopic image of a sample with a high degree of spatial freedom without being affected by a substrate, a scanning probe microscope including the sample holding / scanning mechanism, and a sample holding / scanning mechanism. This is a method for manufacturing a probe used in the method, and has industrial applicability.

S sample
1 Sample holding / scanning mechanism
2 Scanning probe microscope
3 Electron microscope
10 X axis probe set
11,12,21,22,31,32 tips
20 Y-axis probe set
30 Z axis probe set
40 Drive mechanism
41 Main unit
42,43,44 Piezoelectric element
50 frames
51,52,53 frame
60 gimbals
61 Large Diameter Ring
62 medium diameter ring
63 small diameter ring
70 Support members
80 Column
100 controller
101 CPU

Claims (8)

An X-axis direction probe set composed of two probes arranged oppositely along the X-axis direction, and a Y-axis direction probe set composed of two probes arranged oppositely along the Y-axis direction, It comprises a Z-axis direction probe set composed of two probes arranged facing each other along the Z-axis direction, and six drive mechanisms for driving each of the six probes at least in the XYZ-axis direction. A sample holding / scanning mechanism wherein another probe scans the sample three-dimensionally in the XYZ axis directions while holding the sample with the above-described probe.
One of the X-axis probe sets, one of the Y-axis probe sets, and one of the Z-axis probe sets, a total of three probes. 2. The sample holding / scanning mechanism according to claim 1, wherein another sample scans the sample three-dimensionally in the XYZ axis directions while holding the sample at three points by the probe.
3. The sample holding / scanning mechanism according to claim 1, wherein the six driving mechanisms are attached to a gimbal having three degrees of freedom of rotation.
4. The sample holding / scanning mechanism according to claim 3, wherein, among the six driving mechanisms, a driving mechanism for driving the probe used for holding the sample is supported separately without attaching the driving mechanism to a gimbal.
One or two of the X-axis direction probe set, the Y-axis direction probe set and the Z-axis direction probe set are removed, and a sample is formed using one of the remaining probe sets. The drive mechanism of the other opposing probe is attached to a gimbal having three degrees of freedom of rotation, and the other opposing probe three-dimensionally scans the sample in the XYZ axis directions. 3. The sample holding and scanning mechanism according to claim 1, wherein
The sample holding / scanning mechanism according to any one of claims 1 to 5, wherein the sample fixed to the probe is used for holding the sample among the probes.
A sample holding / scanning mechanism according to any one of claims 1 to 6, further comprising: the other probe complementarily synthesizing an image obtained by three-dimensionally scanning the sample. A scanning probe microscope comprising an image synthesizing means for obtaining a three-dimensional stereoscopic image of the sample.
In the method for manufacturing a probe used for the sample holding and scanning mechanism according to any one of claims 1 to 6,
Fixing both ends of a columnar member to be a probe material to the driving mechanism;
Performing a taper process so that the cross-sectional area decreases from both ends of the columnar member toward the center in the longitudinal direction,
A method for manufacturing a probe, comprising a step of manufacturing the two opposed probes by separating the columnar member into two at the minimum position of the cross-sectional area.

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