JPH05307778A - Recording and reproducing device - Google Patents

Abstract

PURPOSE:To shut off dust from the outside and to miniaturize a device by constituting an XY stage system and a probe electrode system integrally and enclosing it by a construction body. CONSTITUTION:Si substrates 15, 18 are attached face to face through a supporting rod 17. Then, a cylindrical type piezoelectric element is advantageous to the supporting rod for correcting inclination. Thus, when a recording medium and the probe electrode 14 are parallel-adjusted, by the elongation and contraction and the deflection of the piezoelectric, fine adjustment is performed. Recording is executed by scanning the medium 13 by a movable part. When the probe 14 arrives at a recording area position, recording is executed by applying a write voltage by a voltage applying circuit 23. Write timing, etc., is controlled by a computer 25 and recording is executed on the recording medium 13 row by row in the direction of X. Reproducing is executed so that a read voltage is applied between the probe 14 and the foundation electrodes of the medium 13 by the voltage applying circuit 23 and the medium is scanned similarly at the recording time and current change is detected by a current amplifier circuit 24. The detected result is informed to an external device through the computer 25. The recording medium, the probe, the Si substrate, the supporting rod, time movable part, an elastic hinge are integrated and housed in a housing 12 and dust-proofed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a small-sized recording / reproducing apparatus having a high density and a large capacity, to which the principle of a scanning tunneling microscope is applied.

[0002]

2. Description of the Related Art In recent years, memory devices and memory systems have been used in various fields such as computers and related devices, video discs, digital audio discs, etc., and have become the core of the electronics industry. In the past, magnetic memories and semiconductor memories were the mainstream, but with the recent development of laser technology, optical memory devices using inexpensive and high-density recording media have appeared. However, as computers are used for home use in the future and information industries centered on images are advancing, it is desired to realize a memory device or a recording / reproducing device having a larger capacity and a smaller capacity.

On the other hand, in recent years, a scanning tunneling microscope (hereinafter referred to as S
(Referred to as TM) has been developed, and it is now possible to measure with high resolution in real space regardless of whether it is a single crystal or an amorphous material. Since the STM uses a method of detecting a minute electric current, it has an advantage that it can be observed at a low power without damaging the measurement material. Further, since it can be used not only in ultra-high vacuum but also in air and solution, and can be used for various materials, it is expected to have a wide range of applications.

Particularly, as one of the expected application fields,
Application as a recording device for writing information in a sample with high resolution and as a reproducing device for reading out information written in a sample with high resolution is being advanced. Thus, in the device to which the STM technology is applied, the probe electrode and the recording medium are set to about 1n.
High precision control technology is required in order to approach m. In addition, a recording / reproducing apparatus having a plurality of probe electrodes has also appeared to increase the recording / reproducing speed.

[0005]

However, this S
In the prior art to which the TM principle is applied, it is necessary to precisely control the distance between the probe electrode and the recording medium on the nm order. Therefore, there are problems that the approaching coarse movement mechanism, the fine movement mechanism, the control circuit, and the like of both are complicated, and the size of the device is increased. Also, dust should not be present between the medium and the probe electrode. Further, in the case of an apparatus having a plurality of probe electrodes, it is necessary to provide a surface alignment mechanism for the surface where the tips of the plurality of probe electrodes are connected and the surface of the recording medium.

The object of the present invention is to improve the approach coarse movement mechanism and the surface alignment mechanism between the probe electrode and the recording medium, to integrally form the XY stage system and the probe electrode system, and to enclose the XY stage system and the probe electrode system in a structure to prevent them from the outside world. It is to block dust and to downsize the recording / reproducing apparatus.

The above is the object of the present invention, and it is an object of the present invention to provide a recording / reproducing apparatus to achieve this.

[0008]

SUMMARY OF THE INVENTION That is, the present invention, which has been made to achieve the above object, provides a recording medium formed on a Si substrate, and a recording medium mounted on a movable portion, which is close to the tip of the recording medium. A probe electrode disposed opposite to each other, a recording pulse voltage application circuit for applying a voltage to the probe electrode to apply a perturbation to the surface of the recording medium, and selectively generate a disturbance on the surface for recording. In a recording / reproducing apparatus having a reproducing current amplifying circuit for detecting a tunnel current between the probe electrode and a recording medium, the probe electrode may be one or more piezoelectric thin films formed on a Si substrate. A plurality of thin film cantilever-like displacement elements formed by stacking electrodes for displacing a piezoelectric thin film in a direction approaching the recording medium by an inverse piezoelectric effect are provided so as to project, and the movable portion is formed on a Si substrate. It is supported by an elastic hinge, in a recording and reproducing apparatus, characterized in that the carriage is displaced by the piezoelectric element in the substrate plane in two directions.

In the recording / reproducing apparatus having the above-described structure, the Si substrate forming the thin film cantilever displacement element and the Si substrate forming the movable portion are integrally structured via the piezoelectric support rod.

[0010]

The control of the movement of the probe electrode in the Z-axis direction is performed by deforming the thin film cantilever-shaped displacement element formed on the Si substrate on which the probe electrode is projected. Further, the movement control of the table on which the recording medium is placed in the XY directions is performed by using a piezoelectric element group for driving the movable table, which is formed on the surface of the Si substrate and supported by a plurality of elastic hinges arranged in parallel, for driving the XY directions. It is performed by expansion and contraction. Further, the two Si substrates are arranged in parallel, and the Z-axis is expanded or contracted by a piezoelectric support rod that supports the space between them.
Performs axial movement control and tilt adjustment.

[0011]

Embodiments of the present invention will be specifically described below with reference to the drawings. Embodiment 1 What is shown in this embodiment is a recording / reproducing apparatus of the present invention.

FIG. 1 shows the configuration of the first embodiment, in which a recording / reproducing apparatus includes a recording medium 13 and a probe electrode 1 in a container 12.
4 and the scanning means. At the bottom of the container 12, a Si substrate 15 that supports a movable portion 16 made of Si capable of scanning in the XY directions is fixed via a parallel hinge portion 20 (described later) made of Si. It is placed on the movable part 16 and can be driven in the horizontal plane, that is, in the XY plane. A support rod 17 is provided around the Si substrate 15.
A Si substrate 18 having a thin film cantilever is supported via a recording medium 13 so as to cover the recording medium 13.
The i substrate 18 is integrally formed with the support rod 17 interposed therebetween.

The piezoelectric thin film cantilever 19 and the STM probe electrode 14 project downward toward the inside of the Si substrate 18 toward the recording medium 13 and can be driven in the vertical direction, that is, the Z direction.

The output of the scanning mechanism drive circuit 21 is connected to the movable portion 16 which can be scanned in the XY directions, and the output of the Z direction drive circuit 22 is connected to the thin film cantilever portion 19. Further, a voltage is applied between the recording medium 13 and the probe electrode 14 by the voltage applying circuit 23, and the current amplifying circuit 24 can detect the current flowing between the recording medium 13 and the probe electrode 14. And
These circuits 21 to 24 are microcomputer 25
It is connected to the.

The recording medium 13 has a Si substrate and a smooth Au film formed thereon in this order from the bottom, and squarylium-bis-6-octylazulene (hereinafter abbreviated as SOAZ) having an electric memory effect is formed on the Si substrate. The recording layer is formed by stacking eight recording layers accumulated by the accumulation method (LB method). The electric memory effect means that a voltage exceeding a threshold value capable of making a transition to a state exhibiting two or more electric conductivity is applied to a thin film recording medium such as an organic monomolecular film arranged between a pair of electrodes or a cumulative film thereof. It means to reversibly make a transition between the low resistance state and the high resistance state and maintain the state.

A microcomputer 25, which controls the entire apparatus system, drives the thin film cantilever portion 19 via a Z-direction drive circuit 22 and moves an Si substrate 15 capable of XY scanning via a scanning mechanism drive circuit 21. The part 16 is driven. The voltage application circuit 23 applies a pulse voltage for writing data during recording between the probe electrode 14 and the recording medium 13 and a read voltage during reproduction between the probe electrode 14 and the recording medium 13 in response to a command signal from the microcomputer 25. At the time of erasing, a pulse voltage for erasing is applied.
The current amplification circuit 24 amplifies a current flowing between the probe electrode 14 and the recording medium 13 at the time of recording or reproducing and transmits the current to the microcomputer 25. Signals from these drive circuits and the like are connected to mechanisms inside the container 12 through electrodes (not shown) provided outside the container 12.

FIG. 2 is a schematic view of a thin film cantilever formed on the Si substrate 18. This is manufactured by a normal IC process. The electrode 1 and the piezoelectric thin film 2 are formed and laminated by photography and patterning, and the probe electrode 14 is manufactured by the lift-off method. This laminated thin film cantilever 19 is anisotropically etched to remove a part of the underlying Si substrate,
It is formed so as to be supported in a cantilever manner from the end of the i substrate 18. In such a structure, the piezoelectric bimorph structure is employed, and when a voltage is applied to the electrode 1, the probe electrode 14 can be moved in the Z-axis direction. Although not shown, this Si substrate has an IC such as a current amplifier circuit.
Is installed.

FIG. 3 is a schematic view of an XY scanning mechanism (corresponding to the movable portion 16 in FIG. 1) of the recording medium formed on the Si substrate. This is a Si substrate formed by etching. The movable table 31 to which the recording medium 13 is attached is supported by a Si frame 33 via a plurality of elastic hinges 32, and the movable table 31 is movable in the X direction with respect to the frame 33. In addition, between the movable table 31 and the frame 33 (C
A driving piezoelectric element 34 described later is attached to -D). The movable base 31 can be moved in the X direction by expanding and contracting the driving piezoelectric element 34. Further, another frame (Si substrate) 15 is arranged outside the frame 33, and the frame 33 is supported by the Si substrate 15 via a plurality of elastic hinges 36 and is movable in the Y direction with respect to the Si substrate. The driving piezoelectric element 35 that causes a displacement in the Y direction during the period (AB) is attached so as to sandwich the frame 33 from the Y direction, and the same configuration is performed, and the driving in the X direction and the Y direction is performed. Can be done independently. These were prepared by subjecting Si to lithography by a normal IC process, anisotropic etching, and isotropic etching.

FIG. 4 is an enlarged view of the driving piezoelectric elements 34 and 35. This is also configured by the hinge 42 made of Si as described above. When the piezoelectric body 41 is expanded and contracted, it is shown in FIG.
Like, the mechanism has a mechanism that the displacement is magnified by the lever principle. As a result, the recording medium can be scanned in the X and Y directions. Since it is possible to form a small hinge with high precision by using Si by lithography, it is possible to integrate and form an enlargement mechanism and the like. However, if the size is reduced, the size of the piezoelectric element that can be mounted becomes smaller, and as a result, the displacement amount of the piezoelectric element becomes smaller.
As a result, in order to make a large displacement, a displacement magnifying mechanism using a Si elastic hinge is further required.

Next, the connection between the above-mentioned two types of Si substrates, that is, the substrate 18 of the Z-axis scanning probe having a thin film cantilever and the substrate 15 for XY scanning the recording medium will be described.

As shown in FIG. 1, these Si substrates are mounted face-to-face with a support rod 17 interposed therebetween. For this reason, it is preferable to use a cylindrical piezoelectric element for the support rod 17 to correct the inclination. Accordingly, when the recording medium and the probe electrode are parallelly extended, it is preferable to perform fine adjustment by expanding and contracting and bending the cylindrical piezoelectric element.
Regarding this connection, anodic bonding may be used, or bonding with a normal adhesive may be used. However, the support rod 17 may be made of a material other than the cylindrical piezoelectric element.

Recording / reproducing according to the present invention will be described with reference to FIG.

For recording, the recording medium 13 is scanned by the movable portion 16 capable of XY scanning. When the probe electrode 14 reaches the position of the recording area, the writing voltage is applied by the voltage application circuit 23. This writing voltage is a voltage sufficient for the recording layer having the electric memory effect to change to the ON state (low resistance state). Writing timing and the like are controlled by a control signal from the microcomputer 25. Recording is performed while moving the recording medium 13 in the X direction,
When the recording for one column in the X direction is completed, the recording is shifted by one step in the Y direction, and the recording for one column is similarly performed in the next column. During scanning of the recording medium 13, a writing voltage is applied at each writing position on the recording medium 13. As a result, recording bits are formed.

For reproduction, the probe electrode 14 and the recording medium 13 are used.
Of the read voltage of, for example, 0.1 V between the base electrode (necessary because the recording layer is insulative).
While applying the voltage, the XY scanning mechanism 16 is used to scan the recording medium 13 along the same path as during recording, and the current amplification circuit 24 detects a current change. The reading voltage is set to a sufficiently small value so that the recording layer does not change its resistance value. Actually, the output value of the current amplification circuit 24 obtained by scanning the recording medium 13 is
4 and the current flowing through the base electrode of the recording medium 13 was 10 nA or more at the position of the recording bit and 10 pA at other positions. This change in current is transmitted to an external device through the microcomputer 25, and the timing of reading is also controlled by the control signal from the microcomputer 25. ..

In any of the above recording and reproducing, stable recording and reproducing can be performed, and the size of the recording bit is 90 nm in diameter.
Therefore, high-density recording was possible. Embodiment 2 This embodiment describes a recording / reproducing apparatus having a plurality of probe electrodes.

FIG. 5 is a perspective view of a plurality of thin film piezoelectric cantilevers described in the first embodiment. Si substrate 4
The probe electrode 14 projects from the free end of the thin film piezoelectric cantilever 19 mounted on the substrate 3. An IC 45 including wiring is mounted on the Si substrate 43. This IC4
Reference numeral 5 incorporates a multiplexer or the like for independently controlling a plurality of thin film piezoelectric cantilevers.

FIG. 6 is a sectional view of the recording / reproducing apparatus having a plurality of probe electrodes, showing the positional relationship among the probe electrodes 14, the recording medium 13 and the supporting rods 17. The thin film piezoelectric cantilever 19 bends the support rod 17 so as to drive the probe electrode 14 in the Z-axis direction, and performs tilt correction. The movable portion 16 having an elastic hinge made of Si is formed on the Si substrate 15.

FIG. 7 is a perspective view of this recording / reproducing apparatus. As described above, in this container 12, the recording medium 13 is arranged so as to face a plurality of probe electrodes, and the thin film piezoelectric cantilever 19 for scanning the probe electrodes 14 in the Z direction and the recording medium 13 are arranged in the XY direction. A Si substrate 15 that can be scanned in any direction and a support rod 17 for tilt correction are built in. The plurality of electrodes 46 exposed on the front surface are
The probe electrode 14 in the container 12, the base electrode of the recording medium 13, the thin film piezoelectric cantilever 19, and the recording medium
It is electrically connected to each of the Y-scanned Si substrates. A guide groove 47 for setting a recording / reproducing apparatus in a processing system is provided on the front side of the lateral surface.

When information is recorded on the recording medium 13, recording and reproduction can be performed in a large capacity in a short time as in the first embodiment.

[0030]

As described above, according to the present invention, the ST
As a recording / reproducing device to which the principle of M is applied, it is not only small in size, high in density and large in capacity as compared with the conventional one, but also forms a thin film cantilever-like displacement element in the Z direction on a Si substrate. By forming a scanning mechanism in the XY directions within the surface of the Si substrate and further arranging the above two Si substrates in parallel and forming a minute gap integrally with the piezoelectric support rods, a thinner, smaller and highly reliable device can be obtained. can get.

[Brief description of drawings]

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

FIG. 2 is a plan view (a) and a sectional view (b) of a thin film piezoelectric cantilever.

FIG. 3 is a plan view showing an XY scanning mechanism.

FIG. 4 is an enlarged view showing the operation of the piezoelectric element portion of the XY scanning mechanism.

FIG. 5 is a perspective view of a plurality of thin film piezoelectric cantilevers.

FIG. 6 is a sectional view of a recording / reproducing apparatus of another embodiment of the present invention.

FIG. 7 is a perspective view of the entire recording / reproducing apparatus.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 electrode 2 piezoelectric thin film 12 container 13 recording medium 14 probe electrode 15, 18, 43 Si substrate 16 movable part 17 support rod 19 piezoelectric thin film cantilever 20 elastic hinge part 21 scanning mechanism drive circuit 22 Z-direction drive circuit 23 voltage application circuit 24 current amplifier 25 microcomputer 31 movable table 32, 36 elastic hinge 33 frame 34 X driving piezoelectric element 35 Y driving piezoelectric element 41 driving piezoelectric element 42 hinge 45 IC 46 electrode 47 guide

 ─────────────────────────────────────────────────── ─── Continued front page (72) Inventor Yu Nakayama 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (72) Inventor Yasuhiro Shimada 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon (72) Inventor Osamu Takamatsu 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (72) Inventor Katsuhiko Shinjo 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc.

Claims (2)

[Claims] 1. A recording medium formed on a Si substrate, a probe electrode having a tip facing the recording medium placed on a movable part and facing the recording medium, and a voltage is applied to the probe electrode to apply the voltage to the probe electrode. A recording pulse voltage application circuit for perturbing the surface of the recording medium to selectively generate disturbance on the surface for recording, and a current amplification circuit for detecting a tunnel current between the probe electrode and the recording medium. In the recording / reproducing apparatus having the above, the probe electrode is an electrode for displacing the piezoelectric thin film on one or more piezoelectric thin films formed on a Si substrate in a direction approaching the recording medium by an inverse piezoelectric effect. A thin film cantilever-shaped displacement element formed by stacking a plurality of layers, the movable portion is supported by a plurality of elastic hinges formed on a Si substrate, and the movable portion is displaced in two directions in the substrate surface by a piezoelectric element. Recording and reproducing apparatus, characterized in that the movable base to be. 2. The recording / reproducing apparatus according to claim 1,
A recording / reproducing apparatus in which a Si substrate forming a thin film cantilever displacement element and a Si substrate forming a movable portion are integrally structured via a piezoelectric support rod.