JPH08221816A - Recording and reproducing device and information processor of scanning type probe microscope and the like - Google Patents

Abstract

PURPOSE: To prevent a probe from being attracted by electrostatic force to a recording medium when applying voltage by providing the above device with a mechanism for limiting the displacement of an elastic member for holding the probe in synchronization with the application of the voltage between the probe and the medium. CONSTITUTION: The three-dimensionally slight spatial displacement of a substrate 102 and the recording medium 101 is caused by driving an X-Y-Z driving element 103 mounted at the bottom of the substrate 102. Then, the X-Y-Z driving element 103 plays the role of an X-Y-Z driving mechanism for moving the substrate 102 in an X-Y direction approximately parallel with the plane of the recording medium 101 and the role of a Z-axis driving mechanism for moving the probe 104 in a Z direction perpendicular to the surface of the recording medium 101. The distance between the probe 104 and the recording medium 101 is adjusted by driving the X-Y-Z driving element 103 in the Z direction to the extent that the probe 104 receives the interatom force of certain magnitude on the recording medium 101. The specified voltage is applied on the probe 104 in such a manner that the probe exists near the surface of the recording medium 101. The probe 104 is pressed to the recording medium 101 by a lever 105 and trances the surface of the recording medium 101.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to recording / reproducing in which a probe is scanned with respect to a medium (recording medium or sample) facing it, and a signal generated from the physical phenomenon is detected to write / read information. The present invention relates to an apparatus or an information processing apparatus such as a scanning probe microscope for observing a surface, and particularly to a mechanism for limiting the displacement of the probe.

[0002]

2. Description of the Related Art A scanning tunneling microscope (hereinafter referred to as STM) is one of surface microscopes having atomic scale spatial resolution.
Or a scanning atomic force microscope (hereinafter AFM)
Scanning probe microscope has been put to practical use. In these scanning probe microscopes, an information recording device has been considered in which recorded information is written in a local area by applying that the probe can access the sample surface at the atomic level. The STM detects the tunnel current flowing when the distance between the biased conductive probe and the conductive sample is close to several angstroms or less, and the STM detects the tunnel current between the probe and the sample so that the tunnel current becomes constant. The probe is scanned while controlling the distance, and a tunnel current or a feedback control signal is imaged to form a surface image. As a recording method applying STM, a voltage is applied between the probe and the recording medium to locally change the surface morphology of the recording medium,
Alternatively, there is a method of changing the conductivity of the recording medium. On the other hand, the AFM detects the atomic force acting on the probe and the sample surface when the probe is brought closer to the sample by a few angstroms or less, and causes the probe to scan the probe in a two-dimensional plane to obtain a surface including unevenness information. Make up the statue. By making the probe conductive,
As with the STM, it is possible to record information by applying a voltage. Further, since the AFM detects the atomic force, it can be used as a recording medium regardless of the conductivity of the material.

An example of a recording device to which AFM is applied is disclosed in Japanese Patent Laid-Open No. 6-96714. The recording is performed by providing a conductor layer on the surface of the probe and applying a voltage between the sample and the probe to form an uneven structure on the surface of the sample. Generally, in AFM, an elastic cantilever having one end fixed and an end needle held near the free end is used as a means for detecting an atomic force, and the probe is held near the free end of the cantilever. There is. The atomic force is detected as a displacement of the cantilever proportional to the atomic force received by the probe.

On the other hand, the scanning probe microscope is
Since the M image represents the distribution of the surface electron density, it represents an actual concavo-convex structure in the case of a simple metal made of the same element, but generally does not necessarily correspond to the actual concavo-convex structure. For example, when a structurally flat sample surface has island-shaped portions having high electric conductivity, the islands are represented as convex portions in the STM image. In contrast, AFM
The image accurately represents the surface relief structure of the material. Therefore, S
If you try to compare the TM image with the actual surface roughness,
It is necessary to acquire AFM images of the same area. But S
In order to perform AFM observation of the area observed by TM, the sample was
It is extremely difficult to replace the FM device and position the probe in the same region as observed by STM, since the observation region is usually a minute region of several hundred nm square or less.

Therefore, there is a method of using a scanning atomic force / tunnel compound microscope (AFM / STM) as a multifunctional microscope for AFM and STM observation with the same apparatus. According to this, by using the probe held by the cantilever used in the AFM and making the probe conductive, the current flowing between the probe and the sample can be detected. In a normal use method, it is possible to apply a bias between the probe and the sample during AFM operation to detect a current, and simultaneously obtain a surface unevenness image and a tunnel current distribution image by the same probe. This device can be used alone as an STM device if the probe is used in a non-contact state with the sample and the tunnel current is detected.

[0006]

However, in the recording / reproducing apparatus to which the above AFM is applied, the probe held by the elastic member such as the cantilever is used,
Although scanning can be performed without destroying the recording medium without strict control of the probe position, there are the following problems when voltage is applied to the probe held by an elastic member such as a cantilever. . That is, when a voltage is applied between the probe and the recording medium, the electrostatic force additionally acts on the atomic force between the probe and the recording medium. This electrostatic force always acts as an attractive force. In normal operation, the distance between the probe and the recording medium is feedback-controlled so that the force including electrostatic force is constant, so abnormal force may be applied to the recording medium even if the electrostatic force changes. There is no. However, if the feedback control is not performed or the feedback control cannot follow, a force corresponding to the electrostatic force will be applied to the probe. A
When the FM is applied as an information recording device, it is not always necessary to control the distance between the probe and the recording medium to be constant, and even when feedback control is performed, the frequency response is limited and the frequency response is limited. Aside from the case where the structure that does not follow the fast motion is adopted, when the response frequency of the feedback control is not limited, the motion that has a frequency component higher than the resonance frequency of the device system is followed due to the characteristics of the device. Is very difficult.

Therefore, when a voltage that rapidly changes during recording is applied, the feedback control cannot completely follow the sudden change in electrostatic force, so that a temporary strong attractive force is generated between the probe and the recording medium. Joining can happen. Conventionally, in such a case, there is a problem in that the tip of the probe is pressed against the recording medium with a strong force and the recording medium is destroyed. Further, when the probe is pulled to the recording medium, the electric field strength increases with a decrease in distance, which causes a problem that the recording medium is destroyed.

Further, in the above-mentioned scanning probe microscope, when the STM image is acquired by using the conventional AFM / STM, since the probe held by the cantilever of the elastic member is used, the following problems occur. There is. That is,
When operating the AFM / STM in the STM mode, the normal STM
Similarly, the probe sample interval is controlled so that the tunnel current flowing when the probe is brought close to the sample is constant, and the tunnel current or the feedback control signal is imaged. However,
At a distance close enough to allow a tunnel current to flow, the atomic force acts at the same time, and the cantilever is displaced according to the atomic force. The atomic force depends on the distance between the probe and the sample. Even if the tunnel current is controlled to be constant, the displacement of the cantilever also changes if the atomic force varies depending on the location. Therefore, the amount of displacement of the piezo and the amount of displacement of the probe that have been feedback-controlled do not match. As described above, since the STM image using the cantilever is always affected by the atomic force, there is a problem that an image different from the general STM using the probe having high rigidity is obtained. Further, if the displacement of the cantilever is different, the deflection of the cantilever causes the displacement of the probe position. In this case, STM image and AF
Even if the two images are compared after the M image is acquired, there is a problem that there is no guarantee that the images are in the same area.

Therefore, it is a main object of the present invention to provide an information processing apparatus in which the probe is prevented from being attracted to the medium by applying a voltage between the probe and the medium. It is another object of the present invention to provide a highly safe information recording / reproducing apparatus which prevents the medium from being destroyed by the fact that the probe is attracted to the medium by applying a voltage. A further object of the present invention is to provide a scanning probe microscope capable of acquiring an accurate AFM image and STM image of the same region using the same probe in an AFM / STM combined device.

[0010]

In order to solve the above-mentioned problems, an information processing apparatus of the present invention causes a probe held by an elastic member to scan a medium facing the probe and cause a physical phenomenon thereof. In an information processing device that detects a signal and performs information processing, a mechanism for limiting displacement of an elastic member holding the probe in synchronization with voltage application between the probe and a medium is provided. To do. And
In the present invention, the elastic member may have a torsion type lever structure including a rigid body supported by an elastic supporting portion. In the present invention, the torsion type lever constitutes a probe holding mechanism, and a lever portion made of a rod-shaped or plate-shaped rigid body is supported at two places by a support portion made of an elastic member having torsion elasticity, that is, a torsion bar. It has a structure supported by the lever holding portion, and the probe is held near the tip of the lever. When a force is applied to this probe, the lever is rotationally displaced about the axis connecting the two torsion bars as a fulcrum until it balances the torsional force of the torsion bar. However, the lever has a rigidity such that it is not deformed by an atomic force received by the probe during a normal AFM operation or an electrostatic force applied when a voltage is applied to the probe. The displacement at the probe position can be detected by detecting the rotational displacement of the lever. As a mechanism for limiting the displacement of the elastic member, the elastic portion of the elastic member is brought into contact with a lever portion made of a rigid body of the elastic member, and the lever portion made of a rigid body of the elastic member is opposed to the lever portion. The displacement can be limited by fixing to the holding portion by electromagnetic force such as magnetic force or electrostatic force.
Further, the recording / reproducing apparatus of the present invention is a recording / reproducing apparatus that scans a probe held by an elastic member with respect to a recording medium facing the probe and detects a signal generated from a physical phenomenon to perform recording / reproduction. It is characterized in that a mechanism for limiting the displacement of the elastic member holding the probe is provided in synchronism with the voltage application for recording. Furthermore, the scanning probe microscope of the present invention scans the probe held by the elastic member with respect to the sample surface facing the probe to detect a signal generated from the physical phenomenon, and the detection signal is kept constant. In a scanning probe microscope that observes the surface by controlling the distance between the probe and the sample by performing feedback control so that the elastic member holds the probe in synchronization with the bias application between the probe and the sample. The feature is that a mechanism for limiting the displacement of is provided. And, the mechanism for limiting the displacement of the elastic member in this scanning probe microscope is a lever part of a torsion type lever in which a lever made of a rigid body is supported by an elastic supporting part, and an expanding / contracting part of an expanding / contracting mechanism from one side or both sides. It is possible to limit the displacement of the elastic member by bringing them into contact with each other.

[0011]

According to the present invention, as described above, the mechanism for limiting the displacement of the elastic member holding the probe in synchronization with the voltage application between the probe and the medium is provided. It is possible to prevent the probe from being drawn to the medium by applying a voltage. Therefore, when the recording / reproducing apparatus is configured as described above, it is prevented that the probe exerts an excessive force on the recording medium and the recording medium is destroyed. If a scanning probe microscope is configured, STM
During operation, that is, when the bias is applied, the mechanism for fixing the torsion type lever can suppress the displacement of the lever due to the interatomic force acting between the probe and the sample, and during the AFM operation in which no bias is applied, the torsion type is applied. The lever can be freely displaced, and the lever can be displaced according to the atomic force. Therefore, by switching between the STM operation and the AFM operation, it is possible to obtain the STM image and the AFM image with the same probe.

Next, embodiments of the present invention will be described with reference to the drawings.

[0013]

Embodiment 1 FIG. 1 is a schematic configuration diagram of a recording / reproducing apparatus in Embodiment 1 of the present invention, and FIG. 2 is a schematic diagram of a torsion lever used for it. In FIG.
The lever 201 is formed of a rigid thin film, and the probe 202 is formed at one end of the lever 201. The central part of the lever 201 is
It is supported by a lever supporting portion 203 having torsion elasticity, and the lever supporting portion 203 is fixed to a lever holding portion 204. Further, the lever holding portion 204 is fixed to the main body. The lever 201 is not deformed by the force applied when it is normally used in the AFM, and the support portion 20 is not deformed.
3 acts as a spring by twisting, and lever 20
Reference numeral 1 indicates a structure in which the lever support portion 203 can be rotated about a fulcrum. The spring constant of the lever 201 is the lever support 2
03 elastic constant and the probe 20 from the lever supporting portion 203.
It depends on the distance of 2. In this embodiment, the probe 202 and the lever 201 are formed of a non-conductive material in order to increase the strength of the structure, and the surfaces thereof are applied to apply a voltage between the counter electrode and the substrate 102. A metal such as Pt was vacuum deposited. Further, the probe 202 and the lever 201 may be formed of a conductive material. As the recording method, a change in conductivity of the recording medium due to application of voltage can be used. In this case, the recording medium is, for example, Japanese Patent Laid-Open No. 63-16155.
It is possible to use a cumulative film of an organic compound having an electric memory effect for the current-voltage characteristic as disclosed in Japanese Patent Laid-Open No. Further, as a recording method, a method of causing unevenness on the surface of the recording medium by applying a voltage can be used. In this case, for example, a metal is detached from the tip of the probe by applying a voltage and deposited on the recording medium to form a convex structure, or an electron is locally detached from the recording medium by applying a voltage to form a concave structure. The method etc. can be raised. Further, there is also a method of causing a recording medium to be oxidized by applying a voltage as the recording in which the conductivity change and the surface morphology change are simultaneously performed. In this example, a polyimide LB film was used as the recording medium, and the change in conductivity of the recording medium due to voltage application was used as the recording method. Gold was vacuum-deposited on mica to form a substrate electrode. Further, polyamic acid is LB-coated on the substrate electrode.
Several layers were accumulated by the method and then imidization was performed by heat treatment to form a polyimide LB film. The polyimide LB film can transit between a high resistance state and a low resistance state by applying a voltage of, for example, several V in a pulsed manner. In the recording / reproducing apparatus of the present invention, a probe is used for one of the electrodes, and if a voltage is applied between the substrate and the probe, it is several nm on the recording medium.
It is possible to cause a change in conductivity in a local region of the.

In the schematic diagram of FIG. 1, an XYZ driving element 103 composed of a piezoelectric element is attached to the bottom of a substrate 102. The XYZ driving element 103 is fixed to the main body. The lever 105 faces one surface of the side not holding the probe 104 and the surface opposite to the surface holding the probe 104, and the fixing portion 107 is a main body via an expansion / contraction mechanism including a piezoelectric element. Fixed to. The laser light emitting element 109 was attached to the main body. The direction of the laser light emitted from the laser light-emitting element 109 was adjusted so that the laser light was emitted to one end of the side where the probe 104 is held and the side opposite to the side where the probe 104 is held. . A two-divided sensor composed of a photodiode was used as the laser light receiving portion 110, and was fixed to the main body.

Next, the operation will be described. By driving the XYZ driving element 103 attached to the bottom of the substrate 102, the substrate 102 and the recording medium 101 can be finely displaced three-dimensionally in space. Therefore, the XYZ drive element 103 serves as an XY axis drive mechanism for moving the substrate 102 in the XY directions substantially parallel to the plane of the recording medium 101, and moves the probe 104 in the Z direction perpendicular to the surface of the recording medium 101. It plays the role of a Z-axis drive mechanism. The distance between the probe 104 and the recording medium 101 is such that the probe 104 receives an atomic force of a certain magnitude on the recording medium 101.
It is adjusted by driving the XYZ driving element 103 in the Z direction. A constant voltage is applied to the extent that the probe 104 can be positioned near the surface of the recording medium 101. Probe 10
If 4 is pressed by the lever 105 onto the surface of the recording medium by the elastic force of the supporting portion, the force received by the probe changes as the probe 104 moves due to scanning due to minute irregularities on the surface of the recording medium. The probe traces the surface of the recording medium in a contact state. In addition, since the distance between the probe and the recording medium changes according to the unevenness of the recording medium by scanning the probe, the probe may contact the recording medium or may separate from the recording medium. Should be adjusted so that it is always located near the average horizontal plane of the recording medium. Except when the pulse is applied, the fixed portion 1 is not moved even if the lever 105 is displaced by scanning.
The tip of 07 is separated to the extent that it does not contact the lever 105. The laser light emitted from the laser light emitting element is reflected by the surface of the lever 105 opposite to the surface on which the probe 104 is held, and the reflected laser light is the laser light receiving portion 11
Light is received at 0. The laser light receiving unit detects the deviation amount of the reflection angle of the reflected laser light from the difference in the light amount detected by each laser light receiving unit 110 of the two-divided sensor. The displacement of the lever 105 is measured by the displacement detecting unit 111 from the displacement of the reflected laser light. The deviation signal of the reflected laser light is sent to the fixing mechanism control unit 112 as a feedback control signal for determining the position of the fixing unit 107, and the fixing mechanism control unit 1
Reference numeral 12 drives a piezo element that constitutes the fixing mechanism drive element 108. In this embodiment, the XYZ driving element 103 is configured such that the distance between the probe and the recording medium is not feedback-controlled, but feedback control may be performed so that the distance between the probe and the recording medium is constant. In this case, the deviation signal of the laser light is transmitted to the lever 105.
Is used for feedback control as a displacement signal of.

Next, the operation during recording will be described. In response to a scanning command from the control unit 113, the XYZ drive unit 116
Drives the XYZ drive element 103 to cause the recording medium 101 to scan the probe 104 in XY scanning. When the probe 104 is located at a preset recording point, the scanning is temporarily stopped and the deviation of the laser beam is measured. On the other hand, the fixing mechanism drive element 108 attached to the fixed portion 107 is extended in synchronization with the deviation measurement of the laser light, and the fixed portion 107 approaches the lever 105. When the fixing portion 107 contacts the lever 105, the deviation amount of the laser light changes, but the fixing mechanism driving element 1 is arranged so as to keep the deviation amount of the laser light measured previously.
The piezoelectric element forming 08 is feedback-controlled by the fixing mechanism controller 112. The feedback control of the fixed portion 107 is stopped immediately before the pulse voltage for recording is applied between the probe 104 and the recording medium 101, and the position of the fixed portion 107 is fixed. Next, a pulse voltage of several V for recording is applied between the probe 104 and the recording medium 101 by the voltage application unit 114. The electrostatic force generated between the probe and the recording medium 102 or the substrate 102 due to the voltage application is always an attractive force, and acts in a direction in which the probe is drawn to the recording medium.
On the other hand, one end of the lever 105 that does not hold the probe is the fixed portion 1
Attempt to rotate in the direction approaching 07. Therefore,
If the fixing portion 107 is provided on one side of the lever 105, the movement of the lever 105 when a voltage is applied is limited. After the application of the pulse, even if the lever 105 is displaced by scanning, the fixed portion is separated to a distance that does not contact the lever 105, and scanning is continued.

Next, the reading operation will be described. When recording is performed as a local change in the conductivity of the recording medium as in the present embodiment, a DC bias voltage of several hundred mV is applied between the probe 104 and the substrate 102 by the voltage applying unit, The current flowing between the probe and the recording medium is detected by the current detector 115. The probe 104 scans the recording surface, and a portion where the conductivity is locally changed is confirmed as a recording dot. In the recording / reproducing apparatus according to the present invention, a region having a diameter of 10 nm or less could be changed to a low resistance state, and it could be confirmed as a recording dot. When the recording is performed as a structural change on the surface of the recording medium, the apparatus is operated by AFM, and the unevenness of the surface is detected from the displacement of the lever 105. At this time, the displacement of the lever 105 is detected as the deviation of the reflected laser light. The probe 104 scans the recording surface, and a portion where the surface structure is locally changed is recognized as a recording dot.

[0018]

Second Embodiment In this embodiment, a torsion type lever having the same shape as that shown in the first embodiment is used. FIG. 4 schematically shows a torsion lever in the second embodiment. The lever 401 is formed of a rigid thin film, and the probe 402 is the lever 40.
1 was formed at one end. The central portion of the lever 401 is supported by a lever supporting portion 403 having a torsion spring property, and the lever supporting portion 403 is fixed to a lever holding portion 404. Furthermore, the lever holding part 404 was fixed to the main body. The lever 401 and the probe 402 are made of a non-conductive and non-magnetic material. A wire 406 for applying a voltage to the probe and a wire 407 for forming a coil are provided on the surface of the lever 401 on which the probe 402 is held. The probe 402 is covered with a conductive material. Coil wiring 407 is lever 40
Constant current source 31 via one lever support portion 403
It is connected to 2. Further, the wiring of the probe 402 is connected to the bias circuit through one supporting portion 403 of the lever 401. The coil wiring 407 and the probe wiring 406 for voltage application are separated so as not to interfere with each other.
On the holding portion 105 of the lever 401, a ferromagnetic material 405 was placed so as to face the coiled wiring 407 of the lever 401. A gap is provided between the ferromagnetic body 405 and the lever 401 so that the lever 401 can rotate in a range where the lever 401 does not contact the ferromagnetic body 405. The same polyimide LB film as in Example 1 was used as the recording medium, and recording was performed by causing a change in the electrical conductivity characteristics by applying a voltage. When an electric current is applied to the coil 407 to generate a magnetic field, a magnetic force is generated between the coil 407 and the magnetization of the ferromagnetic material 405, and one end of the lever 401 that does not hold the probe is attracted to the holding portion 105 side and comes into contact with it. Fixed in the state. At this time, the probe 402 slightly moves in a direction away from the recording surface. By maintaining this state, the rotational movement of the lever 401 could be suppressed even if a voltage was applied between the probe 402 and the recording medium 301 and an electrostatic force worked. The ferromagnetic material may be a soft magnetic material or a hard magnetic material, but it is necessary to generate an attractive force with a smaller current in order to limit the current capacity that can be passed through the coil and to suppress heat generation. For this purpose, a hard magnetic material was used in this example and magnetized in advance. In the case of a hard magnetic material, the direction of magnetization and the direction of current flowing in the coil are
It is necessary to have a direction in which an attractive force acts between the coil and the magnetic material. Further, when a soft magnetic material is used, the magnetic body is magnetized in the direction of the magnetic field generated by the coil, so that it is not necessary to consider the direction of the current.

FIG. 3 is a schematic block diagram of the recording / reproducing apparatus in the second embodiment. The probe 402 scans the recording medium in response to a command from the scanning circuit. The scanning is temporarily stopped when the probe is positioned at a preset recording point. An electric current is passed through the coil 407 in synchronization with the position of the probe at the recording point, and the lever 401 is attracted to the holding portion 204 by a magnetic force and fixed in contact therewith. Next, a pulse voltage of several V for recording is applied between the probe 402 and the recording medium 301 by the pulse applying circuit. After the voltage application for recording is completed, the current to the coil 407 is cut off, and the lever 401 returns to its original position by the spring force of the lever support portion 403. The scanning is continued when the lever 401 returns to the predetermined displacement. At the time of recording and reading, the same operation as that of the first embodiment is performed. Also in the recording / reproducing apparatus of this example, it was confirmed that recording dots having a diameter of 10 nm or less and in a low resistance state were formed.

[0020]

Third Embodiment A third embodiment of the present invention will be described below with reference to FIG. FIG. 5 is a schematic configuration diagram of Embodiment 3 of the scanning probe microscope of the present invention. FIG. 6 is a schematic view of the torsion type lever used in this embodiment. In this embodiment, a rigid thin film is used for the torsion lever. Probe 202 '
Is held at one end of the rigid thin film. The central portion of the rigid thin film is fixed to the lever holding portion 204 ′ via the lever supporting portion 203 ′ having a torsion spring property, and the lever holding portion 204 ′ is fixed to the main body. With the above configuration, the lever 201 'can rotate about the lever supporting portion 203' as a fulcrum. The lever 201 ′ is not deformed by a force equivalent to the atomic force that acts during normal AFM operation, and the lever support 203 ′ twists to act as a spring as a whole, depending on the atomic force received by the probe 202 ′. Can be rotationally displaced. The probe 202 ′ and the lever 201 ′ are formed of a conductive material or a non-conductive material and the surfaces thereof are covered with a conductive material, so that a voltage is applied between the probe and the sample which is a counter electrode. And then
Enabled to detect the tunnel current. Lever 201 '
The fixing portion 104 ′ and the fixing portion 105 ′ are arranged so as to oppose both surfaces of the one end which does not hold the probe 202 ′. The fixed portion 104 'and the fixed portion 105' are respectively the expansion and contraction mechanism 10
6'and the expansion / contraction mechanism 107 '. Telescopic mechanism 10
7'is fixed to the main body. On the other hand, the expansion / contraction mechanism 106 'is fixed to the main body via the leaf spring 108'. The sample 101 'was fixed on the sample table 102'. An electrode was attached to the sample table 102 'so that a voltage could be applied between the sample 101' and the probe 202 '. An XYZ drive mechanism composed of a cylindrical piezoelectric actuator was attached to the bottom of the sample table 102 '. Furthermore, the XYZ drive mechanism 103 'was fixed to the main body. The XYZ drive mechanism 103 'is the sample stage 102'.
And that the sample 101 'can be minutely displaced three-dimensionally spatially, the output signal of the drive unit is received, and the sample stage 102' is moved in the XY directions substantially parallel to the sample plane.
It functions to drive the probe 202 ′ in the Z direction with respect to the sample surface. An optical lever method was used to detect the displacement of the lever 201 '. The laser light oscillated from the laser light emitting element 109 'is irradiated to the surface of the lever 201' near the probe 202 ', which is opposite to the surface of the lever 201' opposite to the probe 202 '. The reflected laser light is detected by the laser light receiver 110 '. Laser light receiver 1
A two-divided sensor consisting of a photodiode was used for 10 '. The difference between the signal components of the two-divided sensor is the lever 20.
It is detected as a deviation of the reflection angle of the laser beam in proportion to the displacement of 1 '. The deviation of the laser light is detected by the deviation detecting unit 111 ′ and further sent to the control unit 116 ′. Further, the deviation signal is sent to the fixing mechanism control unit 112 ′ during STM operation and used for position control of the fixing unit 104 ′ and the fixing unit 105 ′. Next, the STM operation will be described. First, the expansion / contraction mechanism 106 ′ for driving the fixed portion 104 ′ that opposes the surface of the lever 201 ′ that does not hold the probe 202 ′ is extended, and the fixed portion 104 ′ approaches the lever 201 ′.
The fixed part 104 'comes into contact with the lever 201' and the lever 20
If 1'is displaced, it is observed as a deviation of the reflected laser light. The expansion / contraction mechanism 106 'is feedback-controlled so that the deviation of the reflected laser light maintains the deviation before contact, and the feedback control is temporarily stopped when the deviation reaches the deviation before contact. Next, the expansion / contraction mechanism 107 'is extended, and the fixed portion 105' is moved to the lever 2.
Approach 01 '. When the fixed portion 105 'comes into contact with the lever 201' and the lever 201 'is displaced, it is observed as a deviation of the reflected laser light. At this time, the expansion / contraction mechanism 104 'is pushed by the expansion / contraction mechanism 105' while sandwiching the cantilever 201 ', but the displacement is limited by the leaf spring 108'. The expansion / contraction mechanism 107 'is feedback-controlled so that the deviation of the reflected laser light is maintained at the deviation amount before the contact. A bias is applied between the probe 202 ′ and the sample 101 ′, and the tunnel current is detected by the current detector. XYZ drive mechanism 103 '
Are driven by a drive unit 114 ′ that receives a signal from the control unit 116 ′, and the sample 101 ′ approaches the probe 202 ′ until the set current value is reached. After reaching the set current value, the distance between the probe 202 ′ and the sample 101 ′ is feedback-controlled in the Z direction by the XYZ drive mechanism 103 ′ so that the tunnel current value becomes constant. This feedback control amount was detected as an STM signal corresponding to the surface structure. Next, AF
The M operation will be described. First, during the AFM operation, the fixed portion is sufficiently separated from the lever 201 ′ to the extent that the fixed portion does not come into contact with the lever 201 ′ even when the lever 201 ′ is displaced. Next, sample 10
1'is brought closer to the probe 202 'by using the XYZ drive mechanism 103' until the probe 202 'receives a certain force on the surface of the sample 101'. At this time, the force received by the probe 202 ′ was observed by the displacement of the lever 201 ′, that is, the displacement signal of the reflected laser light. The deviation signal of the reflected laser light detected by the deviation detection unit 111 ′ is sent to the control unit 116 ′, and the position control of the sample 101 ′ is performed based on this deviation signal.
That is, XYZ so that the reflection angle of the reflected laser light becomes constant.
The drive mechanism 103 ′ is feedback-controlled to control the sample position in the Z direction. On the other hand, the feedback control signal corresponds to the unevenness of the sample A
It is output as an FM signal. After selecting the STM operation or the AFM operation and entering the respective operation states, the control unit 11
6'outputs to the drive unit 114 'to cause the XYZ drive mechanism 103' to perform XY scanning. The image processing unit 115 ′ performs image processing in correspondence with the position coordinate signal and the STM signal or the AFM signal, and displays the image.

[0021]

[Fourth Embodiment] In the third embodiment, two fixing portions, that is, a fixing portion 104 'and a fixing portion 105' are used, and the lever 201 'is sandwiched and fixed by both fixing portions. But STM
In operation, when the probe is driven in a state of being separated from the sample, the atomic force received by the probe is always attractive. At this time, if the probe suppresses the displacement of the lever in the direction approaching the sample from the set position, the displacement of the lever can be suppressed. In this case, as shown in FIG.
05 'is omitted and only the fixing portion 104' is configured. ST
At the time of the M operation, first, the expansion / contraction mechanism 106 ′ for driving the fixed portion 104 ′ that opposes the surface of the lever 201 ′ that does not hold the probe 202 ′ is extended, and the fixed portion 104 ′ is moved to the lever 20.
Approach 1 '. If the fixed portion 104 'comes into contact with the lever 201' and the lever 201 'is displaced, it is observed as a deviation of the reflected laser light. The expansion / contraction mechanism 106 'is feedback-controlled so that the deviation of the reflected laser light maintains the deviation before contact.
The feedback control is temporarily stopped when the deviation amount before contact is reached. Even if the sample 101 ′ approaches the probe 202 ′ and the attractive force increases, the lever 201 ′ is blocked by the fixed portion 104 ′ and cannot be rotationally displaced. Also, the probe 202 '
When is moved away from the sample 101 ', the attractive force becomes smaller, but the lever 201' is pressed against the fixed portion by the spring force of the support portion, so that it is not rotationally displaced. Therefore, the torsion lever acts as a part of the rigid probe.

[0022]

Fifth Embodiment In the third embodiment, when it is not necessary to strictly determine the displacement of the lever 201 ′, as shown in FIG. 8, only the fixing portion 104 ′ is used, and instead of the fixing portion 105 ′, expansion and contraction is performed. The displacement limiting section 205 having no function is provided. In this case, during the STM operation, the fixed part 10
4'is extended and the lever 201 'is pressed against the displacement limiting portion 205, so that the displacement of the lever 201' can be suppressed.

[0023]

[Sixth Embodiment] A sixth embodiment is different from the third embodiment in the method of suppressing the displacement of the lever during the STM operation. Hereinafter, a torsion type lever according to the sixth embodiment and a method for suppressing displacement of the torsion type lever during STM operation will be described. The torsion lever in the sixth embodiment shown in FIG. 10 has the same structure as the torsion lever in the third embodiment. However, the lever 601 was formed of a non-conductive material. Probe 6
A conductive wire 605 for applying a bias voltage to the probe 602 is provided on the surface holding 02. A conductive wiring 606 was provided on the surface opposite to the surface holding the probe 602 and connected to a constant current source. The conductive wiring 606 functions as a coil by passing an electric current. The conductive wiring 606 is electrically insulated from the conductive wiring 605. The fixing portion 506 is arranged so as to face one surface of one end of the lever 601 which does not hold the probe 602. The fixing portion 506 was fixed to the main body via the expansion / contraction mechanism 507.
Although the fixed portion 506 is made of a non-magnetic material and the surface thereof is coated with a ferromagnetic material, it may be made of a ferromagnetic material. The STM operation will be described with reference to the schematic configuration diagram of the fourth embodiment shown in FIG. The expansion / contraction mechanism 507 is driven, and the fixed portion 506 approaches the lever 601. When the tip of the fixed portion 506 contacts the lever 601 and the lever 601 is displaced,
It is detected as a deviation of the reflected laser light. Telescopic mechanism 50
Reference numeral 7 is feedback-controlled so that the deviation of the reflected laser light maintains the same deviation as the contact surface. Next, when the fixing mechanism control unit 512 drives the constant current source 517 and causes a current to flow through the conductive wiring 606 to generate a magnetic field, an attractive force due to a magnetic force is generated between the fixed mechanism controller 512 and the magnetization of the ferromagnetic material at the tip of the fixing unit 506. Working, the lever 601 was fixed while being in contact with the fixing portion 506. In this state, the lever 601 could not be displaced even when the probe 602 approached the sample 501 and the interatomic force worked, and it acted as a part of the rigid probe. As the ferromagnetic material used for the fixed part 506, a hard magnetic material was used in order to obtain as strong a magnetic force as possible, and was magnetized in advance. The direction of magnetization and the direction of current flowing through the coil were set so that attractive force was exerted between the coil and the magnetic material.

[0024]

[Seventh Embodiment] This embodiment differs from the sixth embodiment in that the STM
This is a method for suppressing the displacement of the torsion type lever during operation. A torsion type lever and a method of suppressing displacement of the torsion type lever in this embodiment will be described with reference to FIG. The torsion type lever in this embodiment is the same as that in the third embodiment.
The structure is similar to that of the torsion type lever shown in. A conductive coating 708 was applied to the back surface of the lever 705. The conductive coating 708 is electrically insulated from the wiring for applying a bias to the probe. A limiting portion 706 is provided so as to face the surface of the lever 705 that does not hold the probe 704 and faces the surface that does not hold the probe 704, and the limiting portion 706 is fixed to the main body via the expansion / contraction mechanism 707. A non-conductive coating 709 is applied to the tip surface of the limiting portion 706. During the STM operation, the expansion / contraction mechanism 707 is extended, and the fixed portion 706 approaches the lever 705. When the fixed portion 706 contacts the lever 705 and the lever 705 is displaced, the deviation of the reflected laser light is observed by the laser light receiving portion 713. The expansion / contraction mechanism 707 is feedback-controlled so that the deviation of the reflected laser light maintains the deviation before contact. Next, a constant bias voltage is applied between the lever and the fixed part. Since the fixed portion 706 and the coating 708 on the lever are separated by the non-conductive coating 709, an electrostatic attractive force is exerted, so that the lever 705 is fixed in contact with the fixed portion 706 or the non-conductive coating 709. The displacement of 705 is limited.

[0025]

As described above, the information processing apparatus of the present invention is configured to provide a mechanism for limiting the displacement of the elastic member holding the probe in synchronization with the voltage application between the probe and the medium. Therefore, it is possible to prevent the probe from being attracted to the recording medium by the electrostatic force when the voltage is applied. Therefore, when configuring the recording / reproducing apparatus in the present invention,
When a voltage is applied, it is possible to prevent the probe from being attracted to the recording medium due to electrostatic force, and the probe exerts an excessive force on the recording medium, causing damage to the recording medium, or the distance between the probe and the recording medium decreases. As a result, it is possible to prevent the recording medium from being destroyed due to an increase in the electrolytic strength, and to provide a highly stable recording / reproducing apparatus.

Further, when the probe microscope is constructed in the present invention, particularly when the AFM / STM combined apparatus is constructed thereby, accurate AFM images and STM images of the same region are obtained by using the same probe. It becomes possible to acquire. Since the torsion lever can be fixed with an arbitrary amount of displacement, it is possible to make the actual displacement of the probe proportional to the feedback signal applied to the piezo element for controlling the position of the sample to keep the tunnel current constant. Therefore, an accurate STM operation can be performed without being affected by the interatomic force.

Further, in the present invention, when the elastic member for holding the probe is constituted by a torsion type lever, the deflection of the lever itself can be eliminated, and the probe position at the time of suppressing the movement of the lever can be eliminated. Since the shake can be suppressed, it is possible to maintain the probe position immediately before the voltage is applied even when the voltage is applied, and it is possible to accurately apply the voltage to the target location. In a probe microscope, the torsion of the lever itself during STM operation, which is observed when a cantilever is used due to the configuration of this torsion type lever,
Alternatively, the deflection can be suppressed, and the probe can be fixed at an arbitrary displacement position, which makes it possible to acquire an accurate STM image in the same region using the same probe after acquiring the AFM image. You can Further, a mechanism for restricting the movement of the lever can be installed at a place apart from the probe and the recording surface, and the device configuration can be simplified.

Furthermore, according to the present invention, as a mechanism for restricting the movement of the elastic member holding the probe, the expansion / contraction part of the expansion / contraction mechanism is brought into contact with the elastic member, or the holding part facing the elastic member is electromagnetized. When adopting a configuration of fixing with force, it is possible to reliably prevent the probe from approaching the recording medium excessively even if the force of pulling the probe toward the recording medium acts due to electrostatic force due to voltage application. it can.
By using this in a probe microscope in particular, it is possible to suppress twisting or bending of the lever itself during STM operation, which can be seen when using a cantilever, and to fix the probe at an arbitrary displacement position. After acquiring the image, it is possible to acquire an accurate STM image in the same region using the same probe.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of a recording / reproducing apparatus according to a first embodiment of the present invention.

FIG. 2 is a schematic diagram of a torsion type lever according to the first embodiment of the present invention.

FIG. 3 is a schematic configuration diagram of a recording / reproducing apparatus according to a second embodiment of the present invention.

FIG. 4 is a schematic diagram of a torsion type lever according to a second embodiment of the present invention.

[Explanation of symbols]

 101 recording medium 101 'sample 102 substrate 102' sample stage 103, 103 'XYZ drive element 104 probe 104' fixed part 105 lever 105 'fixed part 106 support part 106' expansion mechanism 107 fixed part 107 'expansion mechanism 108 fixed mechanism drive Element 108 'Leaf spring 109, 109' Laser light emitting element 110, 110 'Laser light receiving element 201, 201' Lever 202, 202 'Probe 203, 203' Support part 204, 204 'Lever holding part 205 Displacement limiting part 301 Recording Medium 302 Substrate 303 XYZ drive element 304 Probe 305 Lever 306 Support portion 307 Coil 308 Ferromagnetic material 309 Laser light emitting element 310 Laser light detecting element 401 Lever 402 Probe 403 Support portion 404 Lever holding portion 405 Ferromagnetic material 40 Wiring for voltage application 407 Coil wiring 501 Sample 502 Sample stage 503 XYZ drive mechanism 506 Fixed part 507 Expansion / contraction mechanism 509 Laser light emitting element 510 Laser light receiving part 601 Lever 602 Probe 603 Lever support part 604 Lever holding part 605 Conductive wire 606 Conductivity Wiring 701 Sample 702 Sample stage 703 XYZ drive mechanism 704 Probe 705 Lever 706 Fixed part 707 Expansion / contraction mechanism 708 Conductive coating 709 Non-conductive coating 710 Laser light emitting element 711 Laser light receiving part

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[Procedure amendment]

[Submission date] May 18, 1995

[Procedure Amendment 1]

[Document name to be amended] Statement

[Name of item to be amended] Detailed explanation of the invention

[Correction method] Change

[Correction content]

Detailed Description of the Invention

[0021]

[Fourth Embodiment] In the third embodiment, two fixing portions, that is, a fixing portion 104 'and a fixing portion 105' are used, and the lever 201 'is sandwiched and fixed by both fixing portions. But STM
In operation, when the probe is driven in a state of being separated from the sample, the atomic force received by the probe is always attractive. At this time, if the probe suppresses the displacement of the lever in the direction approaching the sample from the set position, the displacement of the lever can be suppressed. In this case, as shown in FIG. 7, the fixed part 1
05 'is omitted and only the fixing portion 104' is configured. ST
At the time of the M operation, first, the expansion / contraction mechanism 106 ′ for driving the fixed portion 104 ′ that opposes the surface of the lever 201 ′ that does not hold the probe 202 ′ is extended, and the fixed portion 104 ′ is moved to the lever 20.
Approach 1 '. If the fixed portion 104 'comes into contact with the lever 201' and the lever 201 'is displaced, it is observed as a deviation of the reflected laser light. The expansion / contraction mechanism 106 'is feedback-controlled so that the deviation of the reflected laser light maintains the deviation before contact.
The feedback control is temporarily stopped when the deviation amount before contact is reached. Even if the sample 101 ′ approaches the probe 202 ′ and the attractive force increases, the lever 201 ′ is blocked by the fixed portion 104 ′ and cannot be rotationally displaced. Also, the probe 202 '
When is moved away from the sample 101 ', the attractive force becomes smaller, but the lever 201' is pressed against the fixed portion by the spring force of the support portion, so that it is not rotationally displaced. Therefore, the torsion lever acts as a part of the rigid probe.

[Procedure Amendment 2]

[Document name to be amended] Statement

[Name of item to be corrected] Brief description of the drawing

[Correction method] Change

[Correction content]

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of a recording / reproducing apparatus according to a first embodiment of the present invention.

FIG. 2 is a schematic diagram of a torsion type lever according to the first embodiment of the present invention.

FIG. 3 is a schematic configuration diagram of a recording / reproducing apparatus according to a second embodiment of the present invention.

FIG. 4 is a schematic diagram of a torsion type lever according to a second embodiment of the present invention.

FIG. 5 is a schematic configuration diagram of a scanning probe microscope according to a third embodiment of the present invention.

FIG. 6 is a schematic diagram of a torsion lever according to a third embodiment of the present invention.

FIG. 7 is a schematic diagram showing a lever displacement limiting method according to a fourth embodiment of the present invention.

FIG. 8 is a schematic diagram showing a lever displacement limiting method according to a fifth embodiment of the present invention.

FIG. 9 is a schematic configuration diagram of a scanning probe microscope according to a sixth embodiment of the present invention.

FIG. 10 is a schematic diagram of a torsion lever according to a sixth embodiment of the present invention.

FIG. 11 is a schematic view showing a torsion type lever displacement prevention method in Embodiment 7 of the present invention.

[Explanation of reference symbols] 101 recording medium 101 'sample 102 substrate 102' sample stage 103, 103 'XYZ drive element 104 probe 104' fixed part 105 lever 105 'fixed part 106 support part 106' expansion mechanism 107 fixed part 107 'expansion and contraction Mechanism 108 Fixing mechanism drive element 108 'Leaf spring 109, 109' Laser light emitting element 110, 110 'Laser light receiving element 201, 201' Lever 202, 202 'Probe 203, 203' Support portion 204, 204 'Lever holding portion 205 Displacement limiting section 301 Recording medium 302 Substrate 303 XYZ drive element 304 Probe 305 Lever 306 Support section 307 Coil 308 Ferromagnetic material 309 Laser light emitting element 310 Laser light detection element 401 Lever 402 Probe 403 Support section 404 Lever holding section 405 Ferromagnetic material 406 Voltage application wiring 407 Coil wiring 501 Sample 502 Sample stage 503 XYZ drive mechanism 506 Fixed part 507 Expansion / contraction mechanism 509 Laser light emitting element 510 Laser light receiving part 601 Lever 602 Probe 603 Lever support part 604 Lever holding part 605 Conductivity Conductive wiring 606 Conductive wiring 701 Sample 702 Sample stage 703 XYZ drive mechanism 704 Probe 705 Lever 706 Fixed part 707 Expansion mechanism 708 Conductive coating 709 Non-conductive coating 710 Laser light emitting element 711 Laser light receiving part

Claims (7)

[Claims] 1. An information processing apparatus for performing information processing by scanning a probe held by an elastic member with respect to a medium facing the probe and detecting a signal resulting from a physical phenomenon thereof to perform information processing,
An information processing apparatus comprising a mechanism for limiting displacement of an elastic member holding the probe in synchronization with voltage application between the probe and the medium. 2. The information processing apparatus according to claim 1, wherein the elastic member is a torsion type lever in which a rigid lever is supported by an elastic support portion. 3. A mechanism for limiting the displacement of the elastic member is configured to limit the displacement of the elastic member by bringing the telescopic portion of the telescopic mechanism into contact with the lever portion of the torsion lever. The information processing device according to claim 2. 4. A mechanism for limiting the displacement of the elastic member fixes the lever portion of the torsion type lever to a holding portion facing it by electromagnetic force such as magnetic force or electrostatic force to limit the displacement. The information processing apparatus according to claim 2, wherein the information processing apparatus is configured as described above. 5. A recording / reproducing apparatus for performing recording / reproduction by scanning a recording medium, which is held by an elastic member, with respect to a recording medium opposite thereto, and detecting a signal generated from the physical phenomenon to perform recording / reproduction. A recording / reproducing apparatus provided with a mechanism for limiting a displacement of an elastic member holding the probe in synchronization with voltage application. 6. A probe held by an elastic member is scanned with respect to a sample surface facing the probe to detect a signal generated from a physical phenomenon thereof, and feedback control is performed so that the detected signal becomes constant. In a scanning probe microscope that observes the surface by controlling the distance between the probe and the sample by
A scanning probe microscope comprising a mechanism for limiting displacement of an elastic member holding the probe in synchronization with application of a bias between the probe and the sample. 7. A mechanism for limiting the displacement of the elastic member is such that the expansion / contraction part of the expansion / contraction mechanism is brought into contact with the lever part of a torsion type lever having a rigid lever supported by an elastic support part from one side or both sides. The scanning probe microscope according to claim 6, wherein the scanning probe microscope is configured so as to limit the displacement thereof.