JP2001141633A - Scanning probe microscope - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a scanning probe microscope for easily observing the surface of a disk-shaped sample. SOLUTION: The scanning probe microscope consists of an optical signal pickup means 104 for detecting an observation position, a chassis 101 for mounting the pickup means 104, a slight-movement scanning means 102 in the direction of the radius of a disk and in a Z direction being mounted to the chassis 101, a guide rail 105 that freely slide the chassis in one direction, a motor 107 for rotating the disk, a Z rough-movement stage 108 for driving the motor 108 up and down in a height wise direction, a slight-speed rotary means 109 for slightly rotating and driving the rotary shaft of the motor while being mounted to the state 108, a displacement detection means 109 for detecting the displacement of the probe, a feedback circuit 111 for reading a signal from the means 110 and sending a Z-directional drive signal to the scanning means 102, a scanning circuit 112 in the direction of the radius of the disk and in the rotary direction of the disk for generating a scanning signal in the direction of the radius of the disk and in the rotary direction of the disk, and a motor 113.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a scanning probe microscope (SPM) for observing physical information on a sample surface by scanning the sample surface with a probe having a sharpened tip. Scanning probe microscope (S) for observing the surface of a disk-shaped sample such as the surface shape of a compact disk and the pattern on a silicon wafer.
PM).

[0002]

2. Description of the Related Art A scanning probe microscope (SPM) scans a sample surface with a mechanical probe (hereinafter, referred to as a probe) and detects an interaction between the probe and the sample surface to detect the sample. The physical quantity of the surface is ^expressed as nm (10 ^-9
m) A device for observing in the following order. For example, in a typical atomic force microscope (AFM) as one of the scanning probe microscopes (SPM), an atomic force acting between the probe and the sample surface is detected based on information of a change in the deflection of the probe, and this is detected. By using the sample, the surface shape of the sample can be observed.

Conventional scanning probe microscope (SPM)
The scanner generally has a scanning unit for raster-scanning the sample in the X and Y directions, the sample is placed on this, and the probe is positioned on the surface of the sample. Further, the scanning means is provided on the Z coarse movement means for bringing the sample surface close to the probe. For example, in the case of an atomic force microscope (AFM), which is one of the scanning probe microscopes (SPM), the sample surface is brought close to a distance where an atomic force acts between the sample surface and the tip of the probe by Z coarse movement means. By scanning the sample in the XY directions with respect to the probe in this state, the shape of the sample surface and the like can be observed.

FIG. 6 shows a conventional scanning probe microscope (SP).
It is the schematic diagram which showed the structure of M). Cylindrical piezoelectric element 60
1 is fixed with its central axis vertical, and the sample 60
2 is mounted. A probe 603 is arranged above the sample 602. The cylindrical piezoelectric element 601 is provided with a Z coarse movement stage 6 for bringing the surface of the sample 602 and the probe 603 closer to each other.
It is fixed on 04. Above the probe 603, there is a probe displacement detecting means 605, and a feedback circuit 606 is connected to the probe displacement detecting means 605, and the feedback circuit 606 is connected to the cylindrical piezoelectric element 601. At the same time, an XY scanning circuit 607 is connected to the cylindrical piezoelectric element 601.

The sample 602 can be scanned in the X and Y directions and finely driven in the Z direction by the cylindrical piezoelectric element 601. In order to enable this driving, several divided electrodes are formed on the side surface of the cylindrical piezoelectric element 601. By controlling to which electrode a voltage is applied, the cylindrical piezoelectric element 601 can be bent or expanded and contracted. Generally, bending is an operation in the X and Y directions, and expansion and contraction is used as an operation in the Z direction.

The distance between the sample 602 and the probe 603 is detected by a probe displacement detecting means 605. As a probe displacement detecting means, there is a method using an optical lever or an optical interferometer. While the sample 602 is scanned in the XY directions by the XY scanning circuit 607, a drive voltage in the Z direction is applied to the cylindrical piezoelectric element 601 by the feedback circuit 606, and the sample 602 is scanned.
Is controlled so that the distance between the probe 603 and the probe 603 is always constant. By inputting the control signal and the XY scanning signal to the monitor 608, the surface state of the sample 602 can be reproduced as an image.

[0007]

In the early days of STM and AFM, which were the forerunners of the scanning probe microscope (SPM), the objects to be observed were atomic images of metal surfaces and molecular arrangements of monomolecular films. Was used for observing and studying the microstructure of the sample surface. In such an application, since the sample can be ground and prepared as a small section, the configuration of the SPM apparatus described above was sufficient.

On the other hand, in the last few years, as STM and AFM have become common and widely used as measuring devices, their observation objects have been extended to surface observation of industrial materials. The target is
For example, it is a stamper of a compact disk, a bump on a thin film magnetic head, and a pattern on a silicon wafer.

In the case of such a sample, there are many manufacturing processes, and it is often required that the sample be extracted and observed in the middle of the process and then returned to the process after the observation. Therefore, it is desirable to avoid crushing the sample for observation as in the case of observation with a conventional scanning probe microscope (SPM).

In addition, for example, when observing the state of the disk surface, there is a demand that the disk be rotated to optically read a signal, and a portion where the signal has a defect be observed with a probe. In such a case, it is necessary to incorporate a means for rotating the disk, but in a conventional scanning probe microscope (SPM), there was a difficulty due to the positional relationship with the scanning means.

Therefore, an object of the present invention is to solve the above-mentioned problems of the conventional scanning probe microscope (SPM), and in particular, to improve the surface shape of a compact disk and the surface of a disk-shaped sample such as a pattern on a silicon wafer. An object of the present invention is to provide a scanning probe microscope (SPM) that facilitates observation.

[0012]

In order to solve the above-mentioned problems, the present invention provides a scanning type device for observing physical information on a sample surface by scanning the sample surface with a probe having a sharpened tip. A probe microscope,
In particular, in a scanning probe microscope for observing the surface of a disk-shaped sample such as the surface shape of a compact disk and the pattern on a silicon wafer, the sample scanning means can scan in the disk rotation direction and the disk radial direction, and the rotation center is the disk center. It is characterized by being coincident with the rotation center of.

Further, an optical signal pickup means for detecting an observation position, a chassis on which the optical signal pickup means is mounted, a disk radial direction and a Z direction fine movement scanning means mounted on the chassis, a disk radial direction and a Z direction A probe fixed to the fine movement scanning means, a guide rail for allowing the chassis to slide in one direction, a motor for rotating the disk, a Z coarse movement means for driving the motor up and down in the height direction, and a Z coarse movement means. Mounted, a low-speed rotation unit for driving the rotation axis of the motor at a low speed, a displacement detection unit for detecting the displacement of the probe, and reading a signal from the displacement detection unit, and driving the disk in the radial direction and the Z-direction fine movement scanning unit in the Z direction. A feedback circuit for sending a signal; and a disk radial direction and a disk radial direction generating a scanning signal in the disk radial direction and the disk rotational direction. To the disk rotational direction scanning circuit, a monitor, consisting configuration and. As described above, the sample scanning unit is divided and arranged on the probe side and the sample side, and the sample scanning unit is arranged directly below the sample stage by using the motor rotation axis as part of the scanning unit. There is no need and a motor capable of rotating the sample can be installed, and the disk-shaped sample can be mounted without crushing.

Also, when a part of the optical signal detecting means and the scanning means is mounted on one chassis, the signal is read optically by rotating the disk, and it is possible to observe a portion where the signal is defective. In addition, it is possible to provide an apparatus capable of promptly shifting from detection of a defect signal to observation by a scanning probe microscope without moving a sample.

[0015]

Embodiments of the present invention will be described below with reference to the drawings. (Embodiment 1) FIG. 1 is a schematic diagram showing Embodiment 1 of the scanning probe microscope (SPM) of the present invention. In FIG. 1, one end of a disk radial direction and Z direction fine movement scanning means 102 is fixed to a chassis 101.
A probe 103 is fixed to the other end of the disk radial direction and Z direction fine movement scanning means 102. Chassis 10
An optical signal pickup means 104 is provided on the optical disk 1 in addition to the disk radial direction and Z direction fine movement scanning means 102. The chassis 101 is slidably attached to the guide rail 105. Under the chassis 101, the sample 10
6 and the sample 106 is mounted on a rotary motor 107. The rotation motor 107 is further fixed on the Z coarse movement stage 108. The Z coarse movement stage 108 is provided with a fine rotation unit 109. A probe displacement detecting means 110 is provided above the probe 103, and a probe displacement detecting means 1 is provided.
10 is connected to the feedback circuit 111. The feedback circuit 111 is connected to the monitor 113 and the disk radial direction and Z direction fine movement scanning means 102.
Further, the disk radial direction and Z direction fine movement scanning means 10
2 and the low-speed rotation means 109 are connected to a disk radial direction and disk rotation direction scanning circuit 112.

Next, the operation will be described. The sample 106 is rotated in an arbitrary direction by a rotation motor 107. The state of the sample surface can be detected by the optical signal pickup means 104 as information such as a change in light intensity. The configuration of the optical signal pickup unit 104 is, for example, as follows. It is composed of a combination of a photodiode, a collimator lens, a half mirror, and a photodetector for light detection.The light of the photodiode condensed by the collimator lens is reflected on the sample surface,
The reflected light is refracted by the half mirror and enters the photodetector. The amount of reflected light changes depending on the state of the sample surface, and accordingly the output voltage of the photodetector also changes. By monitoring the signal of this photodetector, it is possible to know the state of the sample surface, for example, if there are a number of recesses of a certain shape. If there is a defect or the like in a part thereof, the information can also be detected.

When observing the portion with a scanning probe microscope (SPM) based on such information, first, the rotation of the rotary motor 107 is stopped and the sample 106 is stopped. In this state, the rotation motor 107 is
Is rotated at a very low speed.

The low-speed rotating means 109 is, for example, a feeding device as shown in FIG. Two cylindrical piezoelectric elements 201 are fixed, and elastic friction bodies 202 are fixed to the two free ends. The cylindrical piezoelectric element 201 is an element that can simultaneously excite expansion and contraction and bending movement by a voltage signal to be applied. For example, as shown in FIG.
2 is moved in contact with the rotating shaft 107 (a) of the rotating motor 107, the rotating shaft 107 (a) rotates counterclockwise due to the pressing force and friction due to the elasticity of the elastic friction body 202. On the other hand, as shown in FIG. 4, when the cylindrical piezoelectric element 201 bends left while contracting, the elastic friction body 202
It returns to the initial state without touching 07 (a). If this is continuously operated, the rotating shaft 107 (a) rotates at a low speed counterclockwise, and the sample 106 also rotates at a low speed. Depending on the driving method of the cylindrical piezoelectric element 201, the rotating shaft 107 (a)
It is also possible to rotate clockwise, and by repeating clockwise and counterclockwise rotation intermittently, an important swinging motion during scanning is also possible.

After the position on the sample 106 to be observed is moved to a position immediately below the optical signal pickup means 104 by the low-speed rotation means 109, the chassis 101 is moved so that the probe 103 is positioned above the observation position.

Next, the rotary motor 107 is raised by the Z coarse movement stage 108. Accordingly, the sample 106 also rises, and the surface of the sample 106 and the probe 103 approach each other.
Since the low-speed rotation means 109 also rises in the same manner as the rotation motor 107, the positional relationship between the low-speed rotation means 109 and the rotation shaft 107 (a) does not change. Surface of sample 106 and probe 10
When the distance of 3 approaches a certain distance, an interatomic force acts, whereby the probe 103 is deformed. This probe 10
3 is detected by the displacement detecting means 110. When the amount of deformation reaches a constant value, the Z coarse movement stage 108
To stop.

The probe 103 is fixed to the disk radial direction and Z direction fine movement scanning means 102 and can be finely moved in the disk radial direction and Z direction. This disk radial direction and Z direction fine movement scanning means 1
02 can be constituted by a cylindrical piezoelectric element that excites expansion and contraction and bending motion, similarly to the low-speed rotation means 109. On the other hand, the sample 106 can be rotated at a very low speed in the disk rotation direction by the low-speed rotating means 109.

Here, a signal is output by a disk radial direction and disk rotational direction scanning circuit, and this signal is input to the disk radial direction and Z direction fine movement scanning means 102 to swing the probe 103 in the disk radial direction. Simultaneously, the signal is input to the low-speed rotation means 109 to swing the sample 106 in the disk rotation direction.
06 can be scanned by the probe 103 over a part of the surface. At this time, the feedback circuit 111 controls the distance between the probe 103 and the surface of the sample 106 to be constant.
If 2 is controlled in the Z direction, this series of operations is similar to that of a conventional scanning probe microscope (SPM). FIG. 5 shows the scanning state in the disk radial direction and the disk rotation direction at this time. If the control signal output from the feedback circuit 111 and the signal output from the disk radial direction and disk rotation direction scanning circuits are input to the monitor 113, the surface state of the sample 106 can be reproduced as an image.

The disk radial direction and Z-direction fine-movement scanning means 102 may be formed by integrating a laminated or plate-like piezoelectric element in the disk radial direction and the Z direction in addition to the cylindrical piezoelectric element as in this embodiment. It is also possible to adopt a method of combining them so that they can be driven.

Similarly, the configuration of the low-speed rotation means 109 is not limited to the configuration shown in this embodiment.

[0025]

As described above, the present invention is a scanning probe microscope for observing physical information on a sample surface by scanning the sample surface with a probe having a sharpened tip, In particular, in a scanning probe microscope for observing the surface of a disk-shaped sample such as the surface shape of a compact disk and the pattern on a silicon wafer, the sample scanning means can scan in the disk rotation direction and the disk radial direction, and the rotation center is the disk center. It is characterized by being coincident with the rotation center of.

Also, an optical signal pickup means for detecting an observation position, a chassis on which the optical signal pickup means is mounted, a disk radial and Z direction fine movement scanning means mounted on the chassis, a disk radial direction and a Z direction A probe fixed to the fine movement scanning means, a guide rail for allowing the chassis to slide freely in one direction, a rotation motor for rotating the disk, a Z coarse movement stage for vertically driving the rotation motor, and a Z coarse movement A low-speed rotation unit mounted on the stage and configured to drive the rotation axis of the motor at a low speed;
Displacement detecting means for detecting the displacement of the probe, a feedback circuit for reading a signal from the displacement detecting means and sending a Z-direction drive signal to the disk radial direction and Z-direction fine movement scanning means, and a scanning signal in the disk radial direction and the disk rotational direction And a monitor for scanning in the disk radial direction and in the disk rotation direction for generating the image. As described above, the sample scanning unit is divided and arranged on the probe side and the sample side, and the sample scanning unit is arranged directly below the sample stage by using the motor rotation axis as part of the scanning unit. There is no need and a motor capable of rotating the sample can be installed, and the disk-shaped sample can be mounted without crushing.

Also, when a part of the optical signal detecting means and the scanning means is mounted on one chassis, the disc is rotated to optically read a signal and to observe a portion where the signal has a defect. Scanning probe microscope (SP)
M) There is an effect that it is possible to shift to observation.

[Brief description of the drawings]

FIG. 1 shows a scanning probe microscope (SPM) of the present invention.
FIG. 2 is a schematic diagram illustrating an example of the configuration of the first embodiment.

FIG. 2 is a schematic diagram illustrating an example of a configuration of a low-speed rotating unit according to the first embodiment of the scanning probe microscope (SPM) of the present invention.

FIG. 3 is a schematic diagram showing an example of the operation of the low-speed rotating means in the scanning probe microscope (SPM) according to the first embodiment of the present invention.

FIG. 4 is a schematic view showing an example of the operation of the low-speed rotating means in the first embodiment of the scanning probe microscope (SPM) of the present invention.

FIG. 5 is a schematic diagram showing a scanning state in a disk radial direction and a disk rotation direction of the scanning probe microscope (SPM) according to the first embodiment of the present invention;

FIG. 6 is a schematic diagram showing a conventional scanning probe microscope (SPM).

[Explanation of symbols]

Reference Signs List 101 Chassis 102 Disk radial direction and Z direction fine movement scanning means 103 Probe 104 Optical signal pickup means 105 Guide rail 106 Sample 107 Rotation motor 107 (a) Rotation axis 108 Z coarse movement stage 109 Fine rotation means 110 Probe displacement detection means 111 Feedback circuit 112 Disk radial direction and disk rotation direction scanning circuit 113 Monitor 201 Cylindrical piezoelectric element 202 Elastic friction body 601 Cylindrical piezoelectric element 602 Sample 603 Probe 604 Z coarse movement stage 605 Probe displacement detecting means 606 Feedback circuit 607 XY scanning circuit 608 Monitor

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Claims (3)

[Claims] 1. A scanning probe microscope for observing physical information of a sample surface by scanning the surface of the sample with a probe having a sharpened tip, particularly a surface shape of a compact disk, on a silicon wafer. In a scanning probe microscope (SPM) for observing the surface of a disk-shaped sample such as a pattern, the sample scanning means can scan in the disk rotation direction and in the disk radial direction, and the rotation center coincides with the disk rotation center. Scanning probe microscope (S
PM). 2. An optical signal pickup means for detecting an observation position; a chassis on which the optical signal pickup means is mounted; a disk radial direction and a Z-direction fine movement scanning means mounted on the chassis; A probe fixed to the Z-direction fine-movement scanning means, a guide rail for allowing the chassis to slide in one direction, a rotation motor for rotating a disk, and a Z coarse movement means for vertically driving the rotation motor in the height direction. A low-speed rotation unit mounted on the Z coarse movement unit for driving the rotation axis of the motor at a low speed; a displacement detection unit for detecting the displacement of the probe; A feedback circuit for sending a Z-direction drive signal to a radial and Z-direction fine movement scanning means; 2. A scanning probe microscope (SPM) according to claim 1, further comprising a monitor for scanning in a disk radial direction and a disk rotation direction for generating a scanning signal in a direction, and a monitor. 3. The low-speed rotating means comprises at least two cylindrical piezoelectric elements and an elastic friction member fastened to a free end of the cylindrical piezoelectric element, and the cylindrical piezoelectric element performs expansion and contraction and bending motion. The scanning probe microscope (SPM) according to claim 1 or 2, wherein the scanning probe microscope (SPM) is configured to be excited.