JP3005077B2 - Recording and / or reproducing method and apparatus - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for recording information and / or reproducing information.

[0002]

2. Description of the Related Art An information storage element or an information storage device, a so-called memory, is not only the core of a computer and its related equipment, but also a video device and an audio device as seen in a video disk, a digital audio disk and the like. It occupies an important position among them. The performance required of this memory depends on the application, but in general,

[0003] High density and large recording capacity. Fast response speed for recording and playback. Low power consumption. High productivity and low price. At present, the development of a memory system and a memory medium for realizing such performance is being actively promoted.

Conventionally, the center of a memory has been a magnetic memory and a semiconductor memory using a magnetic material and a semiconductor as a material.
In recent years, with the progress of laser technology, inexpensive and high-density optical memories using organic thin films such as organic dyes and photopolymers have appeared.

At present, technology development for miniaturization of a unit memory bit is proceeding in order to further increase the density and the capacity of these memories, but based on a completely different principle from these conventional memories. There is also a proposal for memory. For example, the concept of a molecular electronic device in which individual organic molecules have functions of a logic element and a memory element is one of them. Although it can be seen that molecular electronic devices have advanced the miniaturization of unit memory bits to the limit, how to access individual molecules has been a problem so far.

On the other hand, recently, a scanning tunneling microscope (hereinafter abbreviated as STM) capable of directly observing the electronic structure of surface atoms of a conductor has been developed, [G. Binning et a
l. , Helvetica Physica Act
a, 55 , 726 (1982)] Real space images can be observed with high resolution regardless of whether they are single crystals or amorphous. S
TM has the advantage that it can be observed at low power without damaging the sample due to electric current. Furthermore, it can be operated in air and can be used for various materials, so it is expected to be applied to a wide area. Have been. Recently, it has been reported that even a molecular image of an organic molecule adsorbed on a conductor surface can be observed.

On the other hand, an atomic force microscope (hereinafter abbreviated as AFM) to which the STM technique is applied has been developed, and [G. Bi
nnig et al. , Pluys Rev. Let
t. , 56 , 930 (1985)] As in the case of the STM, it is possible to obtain surface unevenness information. AFM
Can be measured on an atomic order even for insulating samples, so future development is desired.

The STM utilizes the fact that a tunnel current flows when a voltage is applied between a metal probe (probe electrode) and a conductive substance so that the distance between them is reduced to about 1 mm. This current is extremely sensitive to changes in the distance between them,
By scanning the probe over the surface of the conductive material while controlling the distance between them so as to keep this tunnel current constant, it is possible to draw the surface configuration of the real space of this conductive material and simultaneously Various information on all electron clouds can be read. At this time, the in-plane separation ability is about 1 °. Therefore, if the principle of STM is applied,
It is possible to perform high-density recording / reproduction sufficiently in the atomic order (several Å). In this case, the recording / reproducing method
Recording is performed by changing the surface state of an appropriate recording layer using a high-energy electromagnetic wave such as a particle beam (electron beam, ion beam) or X-ray, or an energy beam such as visible light or ultraviolet light, and reproducing by STM. Method and medium having a recording property as a recording layer, which has a switching property of transitioning to a state having different conductivity by applying a voltage, and has a memory property in which each state having a different conductivity is retained even when no voltage is applied. For example, recording and reproduction are both performed using a thin film layer of an organic compound or a chalcogen compound rich in π-electron conjugated system.
A method using an M apparatus has been proposed.

On the other hand, an atomic force microscope (hereinafter abbreviated as AFM) to which the STM technique is applied has been developed, and [Binn
ig et al. , Pbys. Rev .. Lett. ,
56,930 (1986)] As in the case of the STM, surface irregularity information can be obtained. In the AFM, a cantilever (elastic body) supporting a probe approaching a distance of 1 nanometer or less with respect to a sample surface receives a force applied between the sample and the probe, and generates a force from the amount of bending. By detecting and scanning the sample surface while controlling the distance between the sample and the probe so as to keep this force constant, the three-dimensional shape of the surface is observed with a resolution of nanometers or less. AF
In M, unlike a scanning tunneling microscope (STM), a sample does not need to have conductivity, and an insulating sample, particularly a semiconductor resist surface, a biopolymer, and the like can be observed in the order of atoms and molecules. Therefore, wide application is expected.

[0010]

The problem to be solved by the present invention is that A
One application of FM is a high-density, large-capacity recording / reproducing apparatus. This is described, for example, in Japanese Patent Application Laid-Open No. 1-312753 and in Appl. Phys. Lett. 55 , 1727
(1989) As one of the reproducing methods corresponding to the high-density and large-capacity recording method for locally changing the shape of the recording medium surface as shown in [Albrecht et al.], The above-described AFM principle is used. Reproduction is performed by detecting the amount of deflection of the cantilever (elastic body) that supports the probe brought close to the local shape change due to the force acting between the local shape change and the probe. is there. As a similar device, Japanese Patent Application Laid-Open No. 1-245445 proposes a recording detection device in which the principle of AFM is applied to position control of a probe in a high-density and large-capacity recording / reproducing device in which the principle of STM is applied.

The present invention is an application of the above-mentioned conventional example, and utilizes a force acting between a recording medium and a probe, particularly when a plurality of probes are used for performing large-scale recording and reproduction.
An object of the present invention is to provide a recording and / or reproducing apparatus capable of controlling the distance between all probes and a medium in a simpler manner.

[0012]

According to the present invention, there is provided a method for recording and / or reproducing information on an information recording medium via a plurality of probes, wherein each of the plurality of probes is supported by an elastic body. The position of the plurality of probes with respect to the information recording medium is adjusted by deforming the elastic body by the acting force generated between each of the plurality of probes and the information recording medium.

An apparatus for recording and / or reproducing information on / from an information recording medium via a plurality of probes, comprising: an elastic body supporting each of a plurality of probes; and an elastic body supporting each of the plurality of probes and the information recording medium. And a driving unit for bringing the elastic body into proximity until an acting force generated therebetween is generated, and by deforming the elastic body by the acting force itself,
Position adjustment of the plurality of probes with respect to the information recording medium is performed. Further, in a method of positioning a plurality of probes in opposition to an object, each of the plurality of probes is supported by an elastic body, and an acting force generated between each of the plurality of probes and the information recording medium. The position of the plurality of probes with respect to the information recording medium is adjusted by deforming the elastic body by itself.

[0014]

FIG. 1 is a diagram showing a first embodiment of the present invention. 1, a plurality of conductive probe electrodes 104a, 104 supported by a plurality of elastic cantilevers 101a, 101b, 101c,... (Only the cantilevers 101a, 101b, 101c are shown in the figure).
b, 104c, ... (probes 104a, 104 in the figure)
(only b and 104c are shown) are arranged to face the recording medium 107. Reference numeral 108 denotes a vertical driving element that drives the recording medium 107 in the vertical direction in the drawing, and 109 denotes the cantilever 10.
Reference numeral 110 denotes a cantilever supporting member for supporting the cantilever supporting member, which is a lateral driving element for driving the cantilever supporting member in the horizontal direction in the drawing and the vertical direction in the drawing (only the driving element in the horizontal direction is shown in the drawing). Element 1
08 and 110 are driven and controlled by the position control circuit 120. 111 is a recording voltage application circuit for generating a voltage to be applied between the medium and the probe for information recording, and 112 is a voltage from the recording voltage application circuit 111 between the selected specific probe electrode and the recording medium 107. Switching circuit for applying voltage, 114 is laser light source, 115 is laser light source 1
A lens for condensing the laser light from 14 on the cantilevers 101a,..., 116 is a laser light from the lens 115, and the cantilevers 101a, 101b, 101
A polygon mirror 117 for sequentially scanning c... 117 controls a rotation of the polygon mirror 116 and a rotation speed control circuit 118 for generating information output of the scanning position of the laser beam (that is, which cantilever is irradiated with light). Is a position detection circuit for detecting the spot position on the light receiving surface of the reflected light from the cantilever irradiated with the laser light,
Reference numeral 19 denotes a position detection signal processing circuit that specifies the cantilever irradiated with the laser beam from the output of the circuit 117 and the output of the position detection element 118 and detects the amount of vertical displacement (bending) of the cantilever in the drawing. Reference numeral 113 denotes a control computer which issues a position control command signal to the position control circuit 120 and a command signal corresponding to information recording to the recording voltage application circuit 111 and the switching circuit 112, and records information from the position detection signal processing circuit 119. Receives a signal corresponding to

The multi-cantilever having each probe electrode used here is manufactured as follows. A 0.3 μm thick SiO ₂ film is formed on the surface of the Si substrate by thermal oxidation, and a plurality of cantilevers each having a length of 100 μm and a width of 20 μm are patterned. Next, an electric signal wiring pattern to the probe electrode is formed, and anisotropic etching is performed from the substrate surface using a KOH solution to form a multi-cantilever. Subsequently, a probe electrode having a height of 5 μm is provided at the tip of the cantilever by an electron beam deposition method using carbon or the like. The elastic constant for the deflection of the tip of the multi-cantilever thus manufactured is about 0.01 N / m. In addition, considering the warp of each lever, the process error of the height of the probe electrode, and the like, the variation in the position of the tip of the probe electrode in the height direction with respect to the multi-cantilever support member 109 is about 1 μm. Further, a recording medium whose waviness is reduced to about 1 μm or less is used.

Therefore, the recording medium 107 is moved to the plurality of probe electrodes 104a and 104 by the vertical driving element 108.
, 104c,...
First exerts a force on the probe electrode at the closest distance among the plurality of probe electrodes, then exerts a force on the probe electrode at the second closest distance, sequentially exerts a force, and so on. A force is applied to the probe electrode at the farthest position. Here, which probe electrode the medium exerted a force on and the magnitude of the exerted force can be detected by detecting the amount of bending of each cantilever (for the method of detecting the amount of bending of the cantilever). Will be described later). That is, when the medium approaches a probe electrode with a distance of 1 nanometer or less, a force (repulsive force) acts between the medium and the probe electrode, and the acting force causes the cantilever, which is an elastic body supporting the probe electrode, to bend. This is because the amount of deflection is proportional to the magnitude of the acting force.

Here, the details of the method of causing the plurality of probe electrodes to approach the recording medium will be described with reference to FIGS. FIG. 2 is a top view for explaining an arrangement of a plurality of probe electrodes and an arrangement and a driving method of a vertical driving element.
Is a flowchart showing the procedure. First, a vertical driving element 201z, 20 corresponding to the element 108 in FIG.
2z and 203z are simultaneously driven to support the support member 10 of FIG.
The recording medium 200 (existing in the Z direction with respect to the support member 204) approaches the multi-cantilever support member 204 corresponding to No. 9. The first probe electrode 205 is the one that first approaches the recording medium and detects the acting force among the plurality of probe electrodes. Here, the plurality of probe electrodes on the multi-cantilever support member are equally divided into four regions as shown in FIG.
The region including 5 is defined as a region A, and the other regions are defined as regions B, C, and D. Next, the drive elements 201z, 202z, and 203z are independently driven to move the recording medium 200 relative to the multi-cantilever support member 204 around the axis a passing through the tip of the probe electrode 205 and parallel to the x direction in the figure. Rotate to.
At this time, the direction of rotation is such that the probe electrodes in the areas B and C approach the recording medium. When the probe electrode that has approached the recording medium secondly and has detected the acting force is included in the region A, the probe electrode is newly set as the first probe electrode, and newly passed through the tip of the first probe electrode. An axis parallel to the axis a is set, and rotation is performed as described above. When the probe electrode that has approached the recording medium secondly and has detected the acting force is included in the area C located diagonally to the area A, the drive elements 201z, 202z, and 203z are simultaneously driven from that time, The support member 204 is brought closer to the recording medium by a distance greater than the variation in the position of the tip of the probe electrode in the height direction (〜1 μm in the above example).

When the probe electrode approaching the recording medium secondly and detecting the acting force is included in the region B, the probe electrode is moved to the second position.
As the probe electrode 206, the driving elements Z 1, Z 2, and Z 3 are independently driven, and the axis b passing through the tip of the first probe electrode 205 and the tip of the second probe electrode 206 is set as the center.
The multi-cantilever support member 204 is rotated relative to the recording medium. At this time, the direction of rotation is such that the probe electrode in the area CD approaches the recording medium. Thirdly, if the probe electrode that has approached the recording medium and detected the acting force is included in the area A, the probe electrode is newly added to the first probe electrode. If the probe electrode is included in the area B, the probe electrode is newly added. Then, the axis b is set as the second probe electrode, and the rotation is performed as described above.

Third, when the probe electrode approaching the recording medium and detecting the acting force is included in the region C or D, the driving elements 201z, 202z, and 203z are simultaneously driven from that point on, and the tip of the probe electrode The support member 204 is brought closer to the recording medium by a distance larger than the variation in the position in the height direction (〜1 μm in the above-described example).

When the probe electrode approaching the recording medium secondly and detecting the acting force is included in the region D, the probe electrode is moved to the third position.
Driving elements 201z, 202 are used as probe electrodes 207.
z and 203z are independently driven, and the first probe electrode 205
Axis c passing through the tip of the second probe electrode and the tip of the third probe electrode 207
, The multi-cantilever support member 204 is rotated relative to the recording medium. At this time, the direction of rotation is such that the probe electrodes in the areas B and C approach the recording medium. Thirdly, if the probe electrode that has approached the recording medium and detected the acting force is included in the area A, the probe electrode is newly added if the probe electrode is included in the area D; The axis c is set as a suitable third probe electrode, and rotation is performed in the same manner as described above.

If the probe electrode approaching the recording medium thirdly and detecting the acting force is included in the region B or C, the driving elements 201z, 202z, and 203z are simultaneously driven from that point, and the tip of the probe electrode The support member 204 is brought closer to the recording medium by a distance larger than the variation in the position in the height direction (〜1 μm in the above-described example).

Now, the driving elements 201z, 202
The details of the method of independently driving z and 203z to rotate the recording medium relative to the multi-cantilever support member 204 will be described. In FIG. 2, the case where the driving element 201 is rotated about the axis a first is detected.
z, 202z, 203z: positional distance x in the figure
₁ , x ₂ , y ₁ , and y ₂ are calculated. After that, the driving element 201
z is the direction in which the recording medium and the multi-cantilever support member are separated, the driving element 202Z is also separated in the same direction, and the driving element 203Z is reversed in the approaching direction.
_1: y _1: in proportions such that y _2, by driving, it is possible to perform the rotation about the axis a.

Next, in the case of rotation about the axis b, the position of the second probe electrode, which has detected the second acting force, is detected, and the positional relationship with the driving elements 201z, 202z, 203z: ₃ , x ₄ , y ₃ and y ₄ are calculated. Then, when the drive element 201Z is moved away from the recording medium and the multi-cantilever support member, the drive element 202z is moved in the approach direction, and the drive element 203z is moved away, the ratio of the drive amounts is (x ₁ y ₃ − _{x 3 y 1) :( x 2} y 3 -x
₄ y ₁₎ can perform the rotation about an axis b by driving at a rate such that _{:( x 3 y 2 -x 1 y} 4).

Similarly, for the axis c, the position of the third probe electrode for which the acting force is detected is detected, and the driving element 2 is detected.
01z, 202z, 203z: x in the figure
_5, x _6, calculates the y _5, y _6. Then drive element 201z
In the direction in which the recording medium and the multi-cantilever support member are separated, and in the direction in which the driving element 202z is similarly separated.
03z in the approaching direction, the ratio of the respective drive amounts is
_{(Y 1 x 5 -y 5 x} 1) :( y 2 x 5 -y 6 x 1) :( y 5 x 2 -
y ₁ x ₆ ), the axis c
Can be rotated about

FIG. 3 is a flowchart for the above operation.

The above description is based on the assumption that the vertical driving elements 201z, 202z, 203z and the regions A, B,
The driving element 20 shown in FIG.
Although 4z has been described as being absent, the concept of the present invention is not limited to only this case.
The same applies when a drive element 204z in the figure is provided instead of any of z, 202z and 203z. Also, the vertical driving elements 201z, 202z, 203z, and 204z have four
The same is true for both cases, but in that case,
One element will be driven dependent on the other three elements.

As described above, while detecting the amount of bending of each cantilever when the recording medium 107 is brought close to the probe electrode, the multi-cantilever support member 109 and the recording medium 107 can be By adjusting the intervals and inclinations of the above, it is possible to keep the action force generated between all the probe electrodes and the recording medium and to keep the variation of the action force within a certain range. In the above case (elastic constant of cantilever 0.01 N /
m, variation in the height of the probe electrode tip 1 μm), and variation in the acting force is 0.01 N / m × 1 μm = 10 ⁻⁸ N
It is. Here, in order to further reduce the variation in the magnitude of the force acting between each probe electrode and the recording medium, if the variation in the height of the probe tip is considered to be the same, the elastic constant of the cantilever is reduced. That is, the lever length may be increased or the lever film thickness may be reduced.

As described above, in this embodiment, all the probe electrodes are brought closer to the recording medium by using an elastic body having an elastic constant smaller than the elastic constant of the recording medium surface as a member for supporting the individual probe electrodes. At this time, the deformation of the elastic body due to the force acting between the recording medium and the individual probe electrodes absorbs the variation in the shape and size between the individual probe electrodes due to a process error. This allows all probe electrodes to approach the recording medium without any special circuitry for controlling the spacing between the individual probe electrodes and the medium, and the force acting between the recording medium and the probe electrodes. Can be below a certain level. That is, when a plurality of probe electrodes approach the recording medium, the magnitude of the force acting between each probe electrode and the recording medium must be uniform within a certain range, and reduced to the magnitude of the range. Can be.
Therefore, even if the material of the recording medium or the probe electrode is a material that is easily broken by the force acting between the probe electrode and the recording medium, by the above-described method using a cantilever having a smaller elastic constant than the recording medium, The force above the destruction threshold can be prevented from being applied.
Destruction during playback can be avoided.

As described above, the probe electrodes 101a, 101b, 101c,.
The recording method to be performed will be described below. A horizontal position control signal in the figure is applied from the position control circuit 120 to the horizontal drive element 110, and the tip of the probe electrode is moved to a desired position on the recording medium 105 where recording is to be performed. The switching voltage 112 selects the probe electrode to be applied and applies the recording voltage signal from the recording voltage application circuit 111. Here, as the recording medium, a medium that locally changes in shape due to local voltage application, electric field application, and current is used. For example, a thin film of a metal or a metal compound as described in JP-A-1-32753, specifically, Au, Al,
Furthermore, the document Appl. Phys. Lett. 51. , 2
44 (1987) [Stanfer et al.], A Rh-Zr alloy, a Te-Ti alloy, a Te-Se alloy,
A semiconductor thin film such as an e-C or H-based material or amorphous silicon can be used. At this time, tungsten, Pt-Ir, Pt, or the like is used as a material for the probe electrode. Also, the document Appl. Phys. Let
t. 55. , 1727 (1989) [Albrecht
Other], an etching method by applying a voltage pulse to the graphite surface may be used.

In the examples of the probe electrode and the recording medium described above, the threshold value of the breakdown caused by the force acting between the probe electrode and the recording medium is about 10 ⁻⁶ N. Therefore, the variation in the tip height of the plurality of probe electrodes is 1
μm, the elasticity of the cantilever that supports each probe electrode to avoid destruction due to the force acting between them when approaching the recording medium to the recording medium and scanning for recording / reproducing. The constant is about 0.5N /
m. As a result, the force acting between the recording medium and the probe electrode can be reduced to 10 ⁻⁶ N or less.

A method of reproducing information recorded as a local change in the shape of the recording medium will be described below. A light beam from a laser 114 is condensed by a lens 115 and is incident on a rotating polygon mirror 116. The rotation speed of the polygon mirror 116 is controlled by a rotation speed control circuit 117.
6 rotates, the reflected light beam of the above-mentioned incident light beam becomes a plurality of cantilevers 101a, 101b,
The back surface of 101c,... Is scanned. At this time, the mirror surface of the polygon mirror 116 is inclined from the direction perpendicular to the paper surface of FIG. 1, that is, by rotating the polygon mirror about the axis indicated by M in the drawing, It is possible to scan not only cantilevers arranged in a circle, but also cantilevers arranged in a direction perpendicular to the paper surface. The position of the reflected light beam from the back of the cantilever is detected by the position detecting element 1.
18 to detect. Here, the length of the cantilever is l, and the distance from the back of the cantilever to the position detecting element is L.
When the tip of the cantilever is bent by ΔZ, the position detecting element 11 of the reflected light beam from the back surface of the cantilever
The position of the light spot on 8 is the distance

[0032]

[Outside 1] Only shifts. By detecting the displacement of the light spot by the position detection signal processing circuit 119 based on the signal from the position detection element 118, the amount of deflection of the tip of the cantilever can be detected. Here, a light beam is scanned by the polygon mirror 116, and the deflection amounts ΔZa, ΔZb, ΔZc,... Of the tips of the plurality of cantilevers 101a, 101b, 101c,. It can be detected in a time sharing manner.

Now, the plurality of probe electrodes 104a, 10a
4b, 104c,... Two-dimensionally scan the surface of the recording medium 107, and when the probe electrode comes to the recording position (bit position where the shape has changed), the force applied to the probe electrode from the recording medium by the local shape change And the amount of bending of the cantilever supporting the probe electrode changes. By sequentially detecting the change in the amount of deflection in a plurality of cantilevers in a time-division manner, the recording bits arranged two-dimensionally for each probe electrode are sequentially detected, that is, reproduced.

Hereinafter, a second embodiment of the present invention will be described with reference to FIG. According to the method of forming the cantilever and the method of forming the probe electrode used in the first embodiment, a 100 μm long, 20 μm wide, and 1 μm thick SiO 2 film is formed on a single Si substrate.
_A plurality of _second elastic cantilevers 403 are formed, and a probe electrode 402 is provided at the tip of each cantilever.

As shown in FIG. 4, a Si substrate 404 on which a plurality of cantilevers are formed is fixed to a support 413. The support 413 is attached to the base 407 via at least three piezoelectric elements 414. These piezoelectric elements 4
14 are individually driven by a piezoelectric element control circuit 412 controlled by a microcomputer 411. In addition, a voltage is applied to each probe electrode 402 by the voltage application and current detection circuit 410, and a current flowing between each probe electrode 402 and the recording medium 401 is separately detected. The medium 401 is an xyz fine movement device 405
Thus, it can be moved by a small amount in the x, y, and z axis directions, and can be roughly moved by the xyz coarse movement device 406.

The recording medium was prepared as follows.

Optically polished glass substrate (substrate 4013)
Was washed with a neutral detergent and trichlene, Cr was deposited as a subbing layer by a vacuum deposition method to a thickness of 50 °, and Au was deposited by 400 ° by the same method to form a base electrode (Au electrode 4012).

Next, squarylium-bis-6-octylazulene (hereinafter abbreviated as SOAZ) was added at a concentration of 0.2 mg / m 2.
The chloroform solution dissolved in 1 was spread on an aqueous phase at 20 ° C. to form a monomolecular film on the water surface. The surface pressure of the monolayer waiting for the evaporation of the solvent is increased to 20 mN / m, and the electrode substrate is gently immersed at a speed of 5 mm / min across the water surface while keeping the surface pressure constant. Y-type monomolecular films were accumulated. By repeating this operation four times, a recording medium 401 having a recording layer 4011 in which eight SOAZ layers are accumulated is created.

Next, a specific method of recording, reproducing and erasing will be described.

The recording medium 401 is fixed on the xyz fine movement device 405, the xyz coarse movement device 406 and the xyz fine movement device 405 are driven, and the probe electrode 402 and the Au electrode 4 are moved.
Both are brought close to each other with a bias of 100 mV applied during 012. While monitoring the current flowing between the probe electrode 402 and the recording medium 401, the xyz fine movement device 40
As the drive amount in the z direction of FIG. 5 was changed, a current characteristic (curve indicated by I in the figure) as shown in FIG. 5 was obtained.

On the other hand, the probe electrode 402 and the recording medium 40
When 1 approaches, a force acts between them, and this force deforms the cantilever 403. FIG. 5 also shows the result obtained by measuring the amount of deformation at the same time as the current characteristics by using an optical lever system in which the amount of deformation is detected in advance by the deviation of the reflected beam from the cantilever of the laser beam (the curve indicated by F in the figure). ).

In the α region of FIG. 3 where the distance between the probe electrode 402 and the recording medium 401 is 1 nanometer or less and a repulsive force acts between the probe electrode 402 and the recording medium 401, the current flowing between the two is controlled by the xyz fine movement device. 405 is substantially constant with respect to the driving amount in the z direction. Therefore, in the α operation, the current is first monitored by the circuit 410,
By the control of the microcomputer 411, the probe electrode 402 and the recording medium 401 can be brought close to a distance at which a repulsive force acts between them.

Therefore, the piezoelectric element 414 was controlled so that all the probe electrodes were uniformly brought close to the recording medium 401, and all the probes were brought close to the state of the α region in FIG. Here, the details of the method of bringing all the probe electrodes close to the recording medium are the same as in the first embodiment described with reference to FIGS. 2 and 3, and the current is detected instead of the acting force in the first embodiment. Is what you do.

As described above, when all the probe electrodes are brought closer to the recording medium 401, the piezoelectric element 414 is controlled while detecting the individual current values flowing between the individual probe electrodes and the recording medium 401. By adjusting the distance and inclination between the Si substrate 404 supporting all the cantilevers and the recording medium 401, a current flows between all the probe electrodes and the recording medium, and then the probe electrode and the recording medium And the variation in the magnitude of the repulsion acting between them can be kept within a certain range. For example, assuming that the elastic constant of the cantilever is 0.01 N / m and the variation of the height of the tip of the probe electrode in the z direction is 1 μm, the variation range of the repulsive force is 0.01 N / m × 1 μm = 10 ⁻⁸ N. Here, in order to further reduce the variation in the magnitude of the repulsive force acting between each probe electrode and the recording medium, when the variation in the height of the probe tip is constant, the elastic constant of the cantilever is reduced, that is, The length may be increased or the lever film thickness may be reduced.

As described above, when a plurality of probe electrodes are brought closer to the recording medium, the magnitude of the repulsive force acting between each probe electrode and the recording medium is made uniform within a certain range, and The size can be reduced. Thus, even if the material of the recording medium or the probe electrode is a material that is easily broken by the repulsive force acting between the probe electrode and the recording medium, the method described above using the cantilever having a smaller elastic constant than the recording medium is used. It is possible to prevent a repulsive force equal to or greater than the threshold value of destruction from being applied, and to avoid destruction during recording / reproduction.

In the example of the recording medium of the accumulation film of the organic monomolecular film described in the present embodiment, the threshold value of the breakdown caused by the force acting between the probe electrode and the recording medium is about 5 × 10 ⁻⁸ N. . Therefore, assuming that the variation in the height of the tip of the plurality of probe electrodes is 1 μm, when the plurality of probe electrodes approach the recording medium and perform scanning for recording / reproduction, it is necessary to avoid destruction due to the force acting therebetween. The elastic constant of the cantilever supporting each probe electrode is set to about 0.1.
Make it smaller than 01 N / m. However, since the cantilever has a mechanical strength and a resonance frequency of a certain level (10 KHz) or more due to the limit of the process of manufacturing the cantilever, the elastic constant is actually set to be larger than 0.001 N / m.

After the above-described approaching step is completed, the piezoelectric element 4
14 fixes the position of the support base 413 in the z-axis direction and
By moving the medium 401 in the x-axis and y-axis directions by the fine movement device 405, the medium 401 is scanned by the probe electrode 402. During information recording, the circuit 410 applies a voltage equal to or higher than a threshold voltage for turning on the medium at a predetermined position according to the recording information during the scanning. Thus, information is recorded on the medium 401. At the time of erasing (recording of all 0 signals), a voltage higher than the threshold voltage for returning the medium to the OFF state may be applied in the same manner as at the time of recording according to the erasing information. At the time of reproduction, a circuit 410 detects a current flowing between the probe electrode 402 and the medium 401 while applying a voltage equal to or lower than the above-described threshold during this scanning. The change state of the detected current at this time indicates information recorded on the medium.

Next, an experiment of recording, reproducing and erasing performed in this apparatus will be described.

Under the above-mentioned approaching state, the xyz fine movement device was controlled to measure the current flowing between each probe electrode 402 and the Au electrode 4012 while driving the recording medium in the xy plane. Also showed a current value of about 1 nA, and the fluctuation of the current flowing through each probe electrode during scanning was extremely small. Next, the recording operation will be described with reference to FIG. As described above, while driving the recording medium in the xy plane, individual bit information (FIG.
Based on (a) in FIG. 6, a write pulse train as shown in (b) in FIG. 6 was generated and added. Here, the first bit of the bit information is set as the bit corresponding to the ON state for all the individual bit information (a-1 in the figure).
). After applying the pulse, the recording medium is driven again in the xy plane in the same manner as in the writing, and a bias of 100 mV is applied.
When the current flowing between the probe electrode 402 and the Au electrode 4012 was measured under the applied conditions, a change in current of about four digits was obtained for each probe electrode, and a pulse train obtained by binarizing these current measurement values was obtained. Corresponded to the individual bit information ((a) in FIG. 6) applied to each probe electrode 402.

Next, an erase pulse train as shown in FIG. 6C is generated based on the individual bit information written above. Here, it is assumed that the first bit of all the bit information remains ON and is not erased. The recording medium was driven in the xy plane in the same manner as when writing, the current value was measured, and the drive of the medium was temporarily stopped at the first bit, that is, at the position where the current value first changed by about four digits. At this time, a change of about four digits was observed for all the probe electrodes 402 according to the bit information conditions determined first. Subsequently, the drive of the medium was restarted, and in synchronization therewith, individual erase pulse trains were applied to the individual probe electrodes 402 generated earlier. Again, when the current was measured by driving the recording medium 401 in the xy plane in the same manner as in the writing, all the bits except the first bit showed an OFF state, that is, a current value of about 1 nA, confirming that the erasing was completed. Was.

Instead of the erase pulse used here, of the bit information used for writing, except for the first bit,
Erasing pulse train by selecting an arbitrary bit ((d) in FIG. 6)
Was generated and an erasing experiment was performed in the same manner as described above, and it was confirmed that only the selected bit was erased.

Each of the embodiments described above may be an apparatus for recording only or reproducing only.

[0053]

As described above, according to the present invention, the distance between the probe and the medium can be adjusted more easily, and even when there are a plurality of probes, a special servo circuit for controlling the distance between individual probes is provided. Thus, destruction of the medium and the probe during recording and reproduction can be effectively prevented.

[Brief description of the drawings]

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

FIG. 2 is an explanatory diagram of a method for causing a plurality of probe electrodes to approach a recording medium in the first embodiment.

FIG. 3 is a diagram illustrating a flowchart of a method for causing a plurality of probe electrodes to approach a recording medium in the first embodiment.

FIG. 4 is a configuration diagram of a recording / reproducing apparatus showing a second embodiment of the present invention.

FIG. 5 is a characteristic diagram showing a change in a current flowing between the probe electrode and the recording layer surface and a force acting between the two obtained when the distance between the probe electrode and the recording layer surface is changed.

FIG. 6 is a diagram showing bit information, a recording pulse train, and an erasing pulse train given to one probe electrode in a recording, reproducing, and erasing experiment using a plurality of probe electrodes.

[Explanation of symbols]

 Reference Signs List 101 cantilever 102 cantilever 103 cantilever 104 probe electrode 105 probe electrode 106 probe electrode 107 recording medium 108 vertical drive element 109 multi-cantilever support member 110 horizontal drive element 111 recording voltage application circuit 112 switching circuit 113 control computer 114 laser 115 lens 116 Polygon mirror 117 Rotation speed control circuit 118 Position detection element 119 Position detection signal processing circuit 120 Position control circuit 201 Z vertical drive element 202 Z vertical drive element 203 Z vertical drive element 204 Multi-cantilever support member 205 First probe electrode 206 Second probe electrode 207 Third probe electrode 401 Recording medium 402 Probe electrode 403 Cantilever 404 Support of cantilever Si substrate 405 xyz fine movement device 406 xyz coarse movement device 407 base 408 xyz fine movement device control circuit 409 xyz coarse movement device control circuit 410 voltage application and current detection circuit 411 microcomputer 412 piezoelectric element control circuit 413 support base 414 piezoelectric element 4011 recording layer 4012 Au electrode 4013 glass substrate

Continuation of front page (72) Inventor Kunihiro Sakai 3-30-2 Shimomaruko, Ota-ku, Tokyo Inside Canon Inc. (56) References Patent 2942013 (JP, B2) (58) Fields investigated (Int. Cl. ⁷ , DB name) G11B 9/00 G01N 37/00

Claims (8)

(57) [Claims] 1. A method for recording and / or reproducing information on and from an information recording medium via a plurality of probes, wherein each of the plurality of probes is supported by an elastic body, and the plurality of probes are each connected to the information recording medium. A recording and / or reproducing method, wherein the position of the plurality of probes with respect to the information recording medium is adjusted by deforming the elastic body by the acting force itself generated therebetween. 2. An apparatus for recording and / or reproducing information on an information recording medium via a plurality of probes, comprising: an elastic body supporting each of the plurality of probes; and an elastic body supporting each of the plurality of probes and the information recording medium. A driving unit for bringing the plurality of probes closer to each other until an acting force generated therebetween is generated, and performing the position adjustment of the plurality of probes with respect to the information recording medium by deforming the elastic body by the acting force itself. A recording and / or reproducing apparatus characterized by the above-mentioned. 3. The recording and / or reproducing method or apparatus according to claim 1, wherein the acting force acting between the plurality of probes and the information recording medium is a repulsive force. 4. A method for detecting a position of a specific one of the plurality of probes when deforming the elastic body, calculating a relative positional relationship between the entire plurality of probes and a recording medium from the detected position, 4. The recording and / or reproducing method or apparatus according to claim 1, wherein the whole of the plurality of probes and the information recording medium are relatively driven based on a calculation result. 5. The elastic body has one end fixed to a support,
5. The recording and / or reproducing method or apparatus according to claim 1, wherein the beam and the probe are arranged at the other end. 6. The recording apparatus according to claim 1, wherein the elastic body has an elastic constant of 0.5 N / m or less, and a repulsive force of 10 ⁻⁶ N or less acts as the acting force. And / or a reproduction method or apparatus. 7. A method of positioning a plurality of probes facing an object by positioning each of the plurality of probes with an elastic body, and generating an action between each of the plurality of probes and the information recording medium. A method of positioning a probe, comprising: adjusting a position of the plurality of probes with respect to the information recording medium by deforming the elastic body by a force itself. 8. The probe positioning method according to claim 7, wherein the object is an information recording medium, and the acting force acting between the plurality of probes and the information recording medium is a repulsive force.