JPH05109131A - Method for positioning between recording medium and probe electrode - Google Patents

Abstract

PURPOSE:To perform the high density recording and to perform the recording and reproducing of information with small reading errors by performing the positioning of the recording and reproducing direction to a recording medium surface and the scanning direction of a prove electrode with a positioning means using the rotation mechanism. CONSTITUTION:By a Z-direction fine adjusting and coarse adjusting mechanism 4, until the static capacity can be measured by a pat 2a for detecting a static capacity, plural probe electrodes are made close to recording medium 5. Thus, the measurement output is obtained from a static capacity type displacement gage. Next, by an XY- direction fine adjusting and coarse adjusting mechanism 6, the recording medium 5 are scanned in an X direction. When the area where pats 2a and 2c are overlapped is most, the static capacity of the pat 2a becomes the largest, and at this time, the scanning is stopped. In the same way, the scanning is performed even in the Y direction. As a result, the rotation center of the medium 5 and the rotation center of plural probe electrodes can be matched. Next, by a second positioning means, the scanning direction of the medium 5 and the recording and reproducing direction of information are matched. At a probe electrode 1, a tunnel current is made to flow, and the recording and reproducing are performed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a positioning method for aligning the recording / reproducing direction of a recording medium with the scanning direction of a probe electrode, and more specifically, recording in an information processing device for recording / reproducing information using a probe electrode. The present invention relates to a method of positioning a medium and a probe electrode.

[0002]

2. Description of the Related Art In recent years, with the development of information society, large-capacity memory technology has been developed. Recently, a recording / reproducing apparatus using or applying the principle of a scanning tunneling microscope (hereinafter abbreviated as STM) has appeared.

Such an STM utilizes the fact that a tunnel current flows when a metal probe (tunnel tip) is brought close to a distance of about 1 nm by applying a voltage between conductive materials. This current is sensitive to changes in the distance between the two. By scanning the probe electrode so as to keep the tunnel current constant, various information regarding the whole electron cloud in the real space can be read. At this time, the resolution in the in-plane direction is 0.
It is about 1 nm. Therefore, if the principle of STM is applied, it is possible to perform high-density recording / reproduction on the atomic order (sub-nanometer).

[0004]

However, in the information recording and / or reproducing apparatus using or applying the above STM principle, the recording and / or reproducing direction and the probe at the time of recording and / or reproducing on the surface of the recording medium. The electrodes were not aligned in the scanning direction. Therefore, there are the following problems shown in FIG.

During recording, since the recording direction on the surface of the recording medium and the scanning direction of the probe electrode do not match, Recording capacity is reduced.

[0006]. Some parts are not recorded.

During reproduction, the recording direction on the surface of the recording medium and the scanning direction of the probe electrode do not match. Read errors increase.

The object of the present invention is to solve the above problems,
It is an object of the present invention to provide a method for performing the recording and / or reproducing direction at the time of recording and / or reproducing on the surface of a recording medium and the positioning of the scanning surface of the probe electrode by simpler means.

[0009]

SUMMARY OF THE INVENTION The present invention, which has been made to achieve the above object, has a recording medium for recording / reproducing information, and a plurality of writing / reading devices provided facing the recording medium. In the method of making the recording direction on the recording medium coincide with the scanning direction of the plurality of probe electrodes at the time of recording and / or reproducing while keeping the probe electrodes of the probe electrode parallel to the scanning surface, First positioning means for aligning the reference axis rotating with the reference axis rotating the plurality of probe electrodes in the plane direction, and the recording medium or the plurality of probe electrodes parallel to the scanning plane with the reference axis as a center. The positioning method between the recording medium and the probe electrode is characterized in that the positioning is performed by a second positioning means that relatively rotates while maintaining the above.

Here, as the first positioning means and the second positioning means, specifically, the change in capacitance of the position detecting capacitance pad provided on the surface of the recording medium and the surface of the probe electrode substrate is used. It can be mentioned.

Further, in the first positioning means, a positioning method of setting a reference axis of rotation on the capacitance detection pad, or in the first positioning means, the reference axis of the recording medium and the plurality of probe electrodes is set. A positioning method for setting the center, and the like are included.

Further, the second positioning means rotates the substrate having a plurality of probe electrodes around the reference axis, or the second positioning means rotates the recording medium around the reference axis. A positioning method and the like can be mentioned.

According to such a structure, in the information recording and / or reproducing apparatus using or applying the STM principle,
When recording and / or reproducing on the surface of the recording medium and recording and reproducing directions and the scanning direction of the probe electrode are positioned by a positioning means using a rotating mechanism, high density recording and recording of information with few reading errors and And / or can be regenerated.

[0014]

EXAMPLES Examples of the present invention will be specifically described below.

(Embodiment 1) FIG. 1 is a diagram best showing the features of the present invention. In FIG. 1, 1 is a plurality of probe electrodes made by micromechanics technology, and 2 is a capacitance detection pad used for positioning. Reference numeral 3 is a rotating mechanism for rotating the plurality of probe electrodes while maintaining parallelism with the recording medium, and reference numeral 4 is a Z-direction fine movement / coarse movement mechanism for finely moving / coarsely moving the plurality of probe electrodes in the Z direction. A recording medium 5 is provided with a base electrode 5b formed by vacuum deposition of Cr (undercoat layer) and Au on a substrate 5a obtained by polishing glass.
Further, a recording layer 5c of graphite (HOPG) is provided. The recording layer 5c is adhered onto the base electrode 5b with a conductive adhesive, and the recording / reproducing area on the surface of the recording layer is smoothed by cleavage by atomic order. Reference numeral 6 denotes an XY-direction fine movement / coarse movement mechanism for moving the recording medium 5 in the XY directions. Reference numeral 7 denotes an interface for connecting to an information processing device, which inputs / outputs write / read information, outputs a status, inputs a control signal, and outputs an address signal.

Reference numeral 8 is a control circuit for centrally controlling the interaction between the blocks in the apparatus, 9 is a write / read circuit for writing / reading write / read information (data) according to an instruction from the control circuit 8, and 10 is a read / write circuit. A bias circuit for applying a pulse voltage for writing between the plurality of probe electrodes 1 and the recording medium 5 to write data by a command signal from the writing / reading circuit, or for applying a reading voltage, 11 is a recording A tunnel current detection circuit for detecting a current flowing between the plurality of probe electrodes 1 and the recording medium 5 during reproduction, and 12 a tunnel current detection circuit 11 according to an instruction from the control circuit 8 or the like.
And a plurality of probe electrodes 1 based on signals from the position detection circuit 13
And a positioning circuit that determines the position of the recording medium 5, 14 is a servo circuit that servos the positions of the plurality of probe electrodes 1 and the recording medium 5 based on the servo signal from the positioning circuit 15, 1
5 is a plurality of probe electrodes 1 according to the signal of the servo circuit 14.
Z-direction drive circuit for driving the Z-direction fine movement / coarse movement mechanism 4 of
Reference numeral 16 is an XY direction drive circuit for driving the XY direction fine movement / coarse movement mechanism 6 of the recording medium 5 in accordance with a signal from the servo circuit 14, and 17
Is a rotation mechanism drive circuit that drives the rotation mechanism 3 in accordance with a signal from the servo circuit 14, and 18 is an electrostatic capacitance that detects electrostatic capacitance from a plurality of probe electrodes 1 and electrostatic capacitance detection pads 2 provided on the recording medium 5. It is a capacitance detection circuit.

Although only one control circuit 8, write / read circuit 9, bias circuit 10 and tunnel current detection circuit 11 are shown in the figure, the number of probe electrodes is actually used.

FIG. 2A is a view showing the surface of the recording medium used in this embodiment. Reference numerals 2a and 2b are capacitance detection pads, and 5 is a recording medium. The capacitance detecting pads 2a and 2b are made by a photolithography process, and the positional accuracy thereof is such an accuracy that is determined by the photolithography process. In the present embodiment, the capacitance detecting pad 2a is first
And the capacitance detecting pad 2b was used as the second positioning means.

FIG. 2B is a view of the plurality of probe electrodes used in this embodiment as seen from above (from below in FIG. 1). Five probe electrodes are provided in the X direction and seven probe electrodes are provided in the Y direction. , A total of 35 are arranged. Each probe electrode is provided with wiring for detecting a tunnel current from the tunnel tip 21 or applying a recording signal to the recording layer with a voltage, and each is connected to a tunnel current detection circuit 11 and a bias circuit 10. There is. Reference numeral 23 is a substrate provided with a plurality of probe electrodes. 2c and 2d are capacitance detection pads, which are made by a photolithography process similarly to 2a and 2b, and the positional accuracy thereof is an accuracy determined by the photolithography process. In this embodiment, the capacitance detecting pad 2d is used as the first positioning means, and the capacitance detecting pad 2c is used as the second positioning means.

FIG. 3 is a sectional view showing an example of the structure of the probe electrode. Reference numeral 21 is a tunnel chip for applying a tunnel current or a recording signal to the recording layer with a voltage. Reference numeral 22 denotes a cantilever for moving the tunnel tip in the Z direction, which is formed by micromechanics technology.
By applying an arbitrary voltage to the electrodes 24 and 25, the cantilever can be displaced by the electrostatic force. Reference numeral 26 is a probe electrode having a tunnel tip on the cantilever, and 23 is a substrate on which the probe electrode is formed.

Here, the recording medium 5 shown in FIG.
Attached to the Y direction fine movement / coarse movement mechanism 6. The mounting was performed by fixing the sample holder fixed to the XY direction fine movement / coarse movement mechanism 6 with an adhesive with screws. In addition, the plurality of probe electrodes shown in FIG. 2B were attached to the rotating mechanism 3 using an adhesive. At this time, the rotation axis (rotation center) of the rotation mechanism 3 and the rotation axes (rotation center) of the plurality of probe electrodes are already aligned. The apparatus used in this example has a plurality of probe electrodes X.
The recording medium is fixed in the Y direction, and the recording medium is slightly moved in the XY directions.

Next, the details of the positioning method will be described. First, the rotation center O of the recording medium 5 is moved by the first positioning means.
The rotation centers O ₂ of ₁ and a plurality of probe electrodes are aligned. In this embodiment, the respective rotation centers are set to the center as shown in FIGS. 2 (a) and 2 (b).

More specifically, first, the plurality of probe electrodes are brought close to the recording medium 5 by the Z-direction fine movement / coarse movement mechanism 4 until the capacitance can be measured by the capacitance detecting pad 2a. This time, the capacitance can be measured by bringing the capacitance detection pad 2a close to 100 μm, and the output from the capacitance displacement meter was 10 V in voltage. At this time, the positional relationship between the recording medium 5 and the plurality of probe electrodes is shown in FIG.
As shown in (a), at this time, the scanning surface, the recording medium surface, and the surfaces of the plurality of probe electrodes are already aligned.

Then, the recording medium 5 is scanned in the X direction at 0.1 Hz by the XY direction fine movement / coarse movement mechanism 6. The capacitance of the capacitance detection pad 2a is equal to the capacitance detection pad 2a.
Since it changes depending on the overlapping area of a and 2c, the scanning is stopped when the overlapping area is the largest, that is, when the electrostatic capacitance is the highest. Subsequently, scanning is similarly performed in the Y direction as well, and scanning is stopped when the electrostatic capacitance becomes the highest (FIG. 4).
(B)).

As a result, the center of rotation of the recording medium 5 and the center of rotation of the plurality of probe electrodes can be aligned. In this embodiment, by repeating this operation twice, ± 5 nm
Within the range, the rotation center of the recording medium 5 and the rotation center of the plurality of probe electrodes could be aligned.

Next, the scanning direction of the recording medium 5 and the recording and / or reproducing direction of information are aligned by the second positioning means. More specifically, the plurality of probe electrodes are rotated clockwise or counterclockwise by using the rotating mechanism 3 while maintaining parallel to the recording medium 5. At this time, the capacitances of the capacitance detection pads 2b and 2d are measured, and the rotation is stopped when the value becomes maximum. This makes it possible to match the scanning direction with the information recording and / or reproducing direction.

In this state, when a plurality of probe electrodes are brought close to the recording medium 5 until a tunnel current flows through the probe electrode 1 to record and / or reproduce information, it is possible to perform recording in conformity with the scanning direction and also reproduction. I was able to do it without errors.

In the present embodiment, the capacitance detecting pads 2b and 2d used for the second positioning means are installed at the positions shown in FIG. 2 (b), but this is not restrictive at all.
The position shown in FIGS. 5 and 6 may be used. Further, different electrostatic capacity detection pads are used for the first positioning means and the second positioning means, but one set of electrostatic capacity detection pads is sufficient as shown in FIG.

In the present embodiment, the rotating mechanism 3 is arranged on the side of the plurality of probe electrodes 23, and the plurality of probe electrodes 23 are rotated by the second positioning means.
May be arranged on the recording medium 5 side and the recording medium may be rotated by the second positioning means.

(Embodiment 2) FIG. 8 is a diagram showing a recording medium surface and a plurality of probe electrodes according to a second embodiment of the present invention. The overall configuration is the same as that of the first embodiment, but the rotation center of the recording medium 5 and the plurality of probe electrodes is set on the capacitance detecting pads 2a and 2c as shown in FIG.

Here, the recording medium 5 shown in FIG.
Attached to the Y direction fine movement / coarse movement mechanism 6. The mounting was performed by fixing the sample holder fixed to the XY direction fine movement / coarse movement mechanism 6 with an adhesive with screws. The plurality of probe electrodes shown in FIG. 8B were attached to the rotating mechanism 3 using an adhesive. At this time, the rotation axis (rotation center) of the rotation mechanism 3 and the rotation axes (rotation center) of the plurality of probe electrodes are already aligned.

The apparatus used in this embodiment has a structure in which a plurality of probe electrodes are fixed in the XY directions and the recording medium is finely moved in the XY directions.

Next, the details of the positioning method will be described. First, the center of rotation of the recording medium 5 and the center of rotation of the plurality of probe electrodes are aligned by the first positioning means. More specifically, first, the plurality of probe electrodes are brought close to the recording medium 5 by the Z direction fine movement / coarse movement mechanism 4 until the capacitance can be measured by the capacitance detection pad 2a. This time 100 μm
When the capacitance detecting pad 2a was brought close to the above, the capacitance could be measured, and the value was 10 V in voltage. At this time, the positional relationship between the recording medium 5 and the plurality of probe electrodes is as shown in FIG. 9A, and at this time, the scanning surface and the surface of the recording medium and the surfaces of the plurality of probe electrodes have already matched.

Next, the recording medium 5 is scanned in the X direction at 0.1 Hz by the fine and coarse movement mechanism 6 in the XY directions. The capacitance of the capacitance detection pad 2a is the capacitance detection pad 2a.
And 2c vary depending on the overlapping area, so scanning is stopped when the overlapping area is the largest, that is, when the electrostatic capacitance is the highest. Subsequently, scanning is similarly performed in the Y direction as well, and scanning is stopped when the capacitance becomes the highest (FIG. 9).
(B)).

As a result, the center of rotation of the recording medium 5 and the center of rotation of the plurality of probe electrodes can be aligned. In this embodiment, by repeating this operation twice, ± 5 nm
Within the range, the rotation center of the recording medium 5 and the rotation center of the plurality of probe electrodes could be aligned.

Next, the scanning direction of the recording medium 5 and the recording and / or reproducing direction of information are aligned by the second positioning means. More specifically, the plurality of probe electrodes are rotated clockwise or counterclockwise by using the rotating mechanism 3 while maintaining parallel to the recording medium 5. At this time, the capacitance detecting pads 2b and 2
The capacitance of d is measured, and when the value reaches the maximum, the rotation is stopped. This makes it possible to match the scanning direction with the information recording and / or reproducing direction.

In this state, a plurality of probe electrodes are brought close to the recording medium 5 until a tunnel current flows through the probe electrode 1 to record and / or reproduce information. As a result, recording conforming to the scanning direction is possible and reproduction is also possible. I was able to do it without errors.

In this embodiment, the capacitance detecting pads 2b and 2d used for the second positioning means are installed at the positions shown in FIG. 2B, but this is not restrictive.
The position shown in FIGS. 5 and 6 may be used. Further, if there is no problem in the recording area, the capacitance detecting pad may be arranged at the position shown in FIG.

In this embodiment, the shape of the capacitance detecting pad is shown as a quadrangle, but it may be circular as shown in FIG.

In the present embodiment, the rotating mechanism 3 is arranged on the side of the plurality of probe electrodes 23 and the plurality of probe electrodes 23 are rotated by the second positioning means.
May be disposed on the recording medium 5 side, and the recording medium 5 may be rotated by the second positioning means.

[0041]

As described above, according to the present invention,
The recording and / or reproducing direction on the surface of the recording medium and the scanning surface of the probe electrode can be positioned at the time of recording and / or reproducing, which enables high-density recording and recording and / or reproducing of information with few reading errors. ..

[Brief description of drawings]

FIG. 1 is a schematic block diagram of a positioning means and method of the present invention.

FIG. 2 is a diagram showing a capacitance detection pad provided on the surface of the recording medium according to the first embodiment of the present invention and a diagram showing capacitance detection pads provided on a plurality of probe electrode surfaces. Is.

FIG. 3 is a cross-sectional view of a configuration example of a probe electrode.

FIG. 4 is a diagram showing the eccentricity of the recording medium according to the first embodiment of the present invention and a plurality of probe electrodes, and a diagram showing that the rotation centers coincide with each other by the first positioning means.

FIG. 5 is a diagram showing another example of the positions of the capacitance detecting pads on the surface of the recording medium and the surface of a plurality of probe electrodes according to the present invention.

FIG. 6 is a diagram showing another example of the positions of the capacitance detection pads on the surface of the recording medium and the surface of a plurality of probe electrodes according to the present invention.

FIG. 7 is a diagram showing another example of the first embodiment of the present invention.

FIG. 8 is a diagram showing a capacitance detection pad provided on the surface of a recording medium according to a second embodiment of the present invention and a diagram showing capacitance detection pads provided on a plurality of probe electrode surfaces. Is.

FIG. 9 is a diagram showing eccentricity of a recording medium and a plurality of probe electrodes according to a second embodiment of the present invention, and a diagram showing that the centers of rotation are matched by the first positioning means.

FIG. 10 is a diagram showing another example of the second embodiment according to the present invention.

FIG. 11 is a diagram showing another example of the second embodiment according to the present invention.

FIG. 12 shows the discrepancy between the recording and reproducing directions on the recording medium surface and the scanning surface of the probe electrode during recording and / or reproducing.

[Explanation of symbols]

 1 Probe Electrode 2 Capacitance Detection Pad 2a to 2d Capacitance Detection Pad 3 Rotation Mechanism 4 Z-direction Fine / Coarse Movement Mechanism 5 Recording Medium 5a Substrate 5b Base Electrode 5c Recording Layer 5d Recording Area 6 XY-direction Fine Movement / Coarse Movement Drive mechanism 7 Interface 8 Control circuit 9 Write / read circuit 10 Bias circuit 11 Tunnel current detection circuit (for recording / reproduction) 12 Positioning circuit 13 Position detection circuit 14 Servo circuit 15 Z direction drive circuit 16 XY direction drive circuit 17 Rotation mechanism drive circuit 18 Capacitance Detection Circuit 21 Tunnel Chip 22 Cantilever 23 Plural Probe Electrodes (Substrate) 24 Electrode 25 Electrode 26 Probe Electrode

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Katsunori Hatanaka 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc.

Claims (6)

[Claims] 1. A recording medium for recording / reproducing information and a plurality of probe electrodes for writing / reading, which are provided so as to face the recording medium, are kept parallel to the scanning plane during recording and In a method of matching the recording direction on the recording medium with the scanning direction of the plurality of probe electrodes during reproduction, a reference axis for rotating the recording medium in the plane direction and the plurality of probe electrodes for rotating in the plane direction. The first positioning means for aligning the reference axis with the second positioning means for rotating the recording medium or the plurality of probe electrodes relative to the scanning surface while maintaining the parallel to the scanning surface. A method for positioning between a recording medium and a probe electrode characterized by the above. 2. A capacitance change of a capacitance pad for position detection provided on a substrate having a recording medium and a plurality of probe electrodes is used as the first positioning means and the second positioning means. The positioning method between the recording medium and the probe electrode according to claim 1. 3. The positioning method between the recording medium and the probe electrode according to claim 2, wherein the reference axis is set on the capacitance detection pad in the first positioning means. 4. The positioning method between a recording medium and a probe electrode according to claim 2, wherein the reference axis is set at the center of the recording medium and the plurality of probe electrodes in the first positioning means. 5. The positioning method between a recording medium and a probe electrode according to claim 2, wherein the second positioning means rotates a substrate having a plurality of probe electrodes around a reference axis. 6. The positioning method between a recording medium and a probe electrode according to claim 2, wherein the recording medium is rotated around a reference axis in the second positioning means.