JP2995126B2 - Information processing device - 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 scanning a probe close to a recording medium and recording / reproducing information by physical interaction between the recording medium and the probe. The present invention relates to an information processing device to which the principle is applied.

[0002]

2. Description of the Related Art In recent years, a scanning tunneling microscope (hereinafter, referred to as an STM) capable of directly observing the electronic structure of surface atoms of a conductor.
(Abbreviated as G. Binnig et. Al., Phys. Rev.
Lett., 49 (1982) 57), real space images can be measured with remarkably high sub-nm resolution, regardless of whether they are single crystal or amorphous. Such an STM observes the surface condition of a sample by applying a tunnel current when a voltage is applied between a metal probe (probe) and a conductive sample and the distance between the two is reduced to about 1 nm. is there. This current is very sensitive to changes in the distance between the two, so scan the sample while keeping the tunnel current constant and measure the change in the distance between the probe and the sample, or scan while keeping the distance constant. By measuring the current change at the time, the surface state of the sample can be known with the resolution of the atomic order.

[0003] Analysis using STM is limited to conductive materials, but it has begun to be applied to structural analysis of insulating films formed thinly on the surface of conductive materials. In addition, with the development of STM technology, a technology to measure the surface state by scanning over the sample while detecting various physical interactions occurring between the probe and the sample in close proximity, not limited to the tunnel current, has been proposed. Have been. In addition to having a high spatial resolution, such a device and means use a method of detecting a small signal such as a tunneling current, and thus have the advantage of being able to observe the sample without damage and at low power. Have. Further, since it can be operated in the atmosphere, a wide range of applications is expected.

A recording / reproducing apparatus using this STM is disclosed in, for example, Japanese Patent Application Laid-Open No. 61-80536. In this recording / reproducing apparatus, writing is performed by removing atomic particles adsorbed on the recording medium surface by an electron beam or the like. And S
This data is reproduced by TM.

As a recording layer, a material having a memory effect on the switching characteristics of voltage and current, for example, a thin film layer of a π-electron organic compound or a chalcogen compound is used for recording / recording.
Japanese Patent Laid-Open No. 63-161552 discloses a method of performing reproduction by STM.
And JP-A-63-161553. According to this method, the recording bit size is set to 10n.
Assuming that m, a large capacity recording / reproduction of 10 ¹² bits / cm ² is possible.

Further, a device for forming a plurality of probe electrodes on a semiconductor substrate for the purpose of miniaturization and displacing a recording medium opposed thereto to perform recording is disclosed in Japanese Patent Application Laid-Open No. 62-281138.
And Japanese Patent Application Laid-Open No. 1-196751.

In these devices, probe electrodes for detecting a tunnel current are provided on a plurality of cantilevers formed by a semiconductor process, respectively, and a recording medium opposed thereto is mounted on a cylindrical piezoelectric element to perform circular motion. Thus, recording and reproduction are performed.

When a recording medium is accessed using a multi-probe array head having a plurality of probe electrodes, the probe head substrate and the recording medium substrate must be arranged in parallel. Usually, the distance between these two substrates is set to 1 to 3 μm. Further, the variation amount of the distance is required to be ± 0.5 μm or less.

Further, when recording and reproduction are performed by scanning the surface of the recording medium using the probe head, the position of the probe head and the recording medium in the in-plane direction of the recording medium must be adjusted.

[0010] Unless the alignment in the in-plane direction is performed, the direction to be recorded on the surface of the recording medium does not match the scanning direction of the probe electrode, causing various problems.

As positioning means used for this purpose,
There is a method of detecting a change in capacitance by providing a capacitance pad for position detection. In this method, a flat plate electrode is provided near the recording medium and near the probe electrode, and a change in capacitance when the recording medium and the probe electrode are relatively displaced in the in-plane direction is detected to perform alignment. is there.

In order to perform alignment, at least two pairs of capacitance pads are required to determine two directions, the X direction and the Y direction. The shape of the capacitance pad includes a rectangle, a circle, a comb-shaped electrode, and the like. In addition, in the case of actually performing positioning, it is difficult to quickly perform high-precision alignment. Therefore, an electrostatic pad for coarse adjustment and an electrostatic pad for fine adjustment are often provided. Therefore, four or more pairs of capacitance pads are required to perform positioning with high accuracy.

On the other hand, many elements are formed in a multi-probe array head having a plurality of probe electrodes. First, FIG. 5 is a perspective view of the probe unit 106 created by using the semiconductor manufacturing process technology. A piezoelectric bimorph cantilever 105, which is a mechanism for finely moving the tongue-like piece, is cantilevered on a single-crystal silicon substrate 108,
A probe electrode 104 is formed at a free end of the piezoelectric bimorph cantilever 105 to constitute a probe unit 106. The piezoelectric bimorph cantilever 105 has a layered structure.
1, piezoelectric layer 5002, electrode 503, piezoelectric layer 504,
The electrodes 501, 503, and 505 are stacked, and an extraction electrode 506 is attached to each of the electrodes 501, 503 and 505.
When a voltage is applied to the electrodes 501, 503, and 505 from the extraction electrode 506, the piezoelectric layers 502 and 504 expand and contract. It can be freely displaced also in various XY directions. In the multi-probe array head, a large number of such probe units 106 are integrated and formed on a silicon substrate 108. Further, a part of the drive circuit of these probe units 106 is also provided on the silicon substrate 108.

As described above, a large number of elements are formed in the multi-probe array head. However, as shown in FIG. 5, even a single probe unit 106 requires seven wires. Wiring is becoming denser because only the routing of wiring requires a lot of area on the board, and in addition to this, several pairs of capacitance pads for position detection and its wiring are added. . For this reason, crosstalk occurs between the wirings, and particularly when a minute current such as a tunnel current is detected, such noise significantly impairs the reliability of the device.

[0015]

In a conventional multi-probe array head, a capacitance pad for rough adjustment and a fine adjustment and a plurality of probe units are arranged, and the wiring intervals are narrow. For this reason, there is a problem that crosstalk is easily generated between the wirings, and the reliability of the device is impaired. This is, among other things,
This is because the area occupied in the multi-probe array head is large, which requires two pairs in the X and Y directions for alignment, and two pairs each for coarse adjustment and fine adjustment. The major reason is that the pads are provided on the multi-probe array head and the recording medium, respectively.

An object of the present invention is to provide an information processing apparatus in which crosstalk does not occur by reducing the area occupied by a capacitance pad and providing a margin for wiring intervals in a multi-probe array head.

[0017]

In order to achieve the above object, an information processing apparatus according to the present invention scans a recording medium in parallel with a recording medium by bringing a probe close to the recording medium. As an information processing device for reading information as an obtained fine signal and recording / reproducing information on / from the recording medium, a plurality of plate electrodes provided independently of the probe and the recording medium on the probe side and the recording medium, respectively. And a capacitance detecting means for detecting a capacitance between these electrodes, wherein each of the plurality of plate electrodes has a two-dimensional pattern of the same comb-shaped electrode structure, and Is characterized by comprising a plurality of spatial frequency components.

[0018]

In the information processing apparatus having the above-described configuration, the capacitance pads provided on the probe side and the recording medium side can generate signals for coarse adjustment and fine adjustment in one pattern,
For this reason, the wiring intervals on the probe-side substrate do not become close, and crosstalk does not occur.

[0019]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described based on the illustrated embodiment.

FIG. 1 schematically shows a layout of a multi-probe array head. A plurality of probe units 106, flat electrodes 101a to 101 are provided on a silicon substrate 108.
b, the capacitance detection circuit units 102a to 102b are integrated. 101a is a plate electrode for positioning in the X direction, and 101b is a plate electrode for positioning in the Y direction.
Reference numeral 103 denotes a guard electrode for preventing the influence of capacitance from the outside, which has an effect of increasing the accuracy of positioning. Reference numeral 107 denotes bonding pads for taking out wiring, which are also formed on the silicon substrate 108.

The probe unit 106 is formed by a processing technique called micromachine or micromechanics (for example, K. E., Peterson, “Silicon as a Mechanichal Mater”).
ial ”, Proceedings of the IEEE, 70, 420, 19
1982). The circuit element can be easily formed by a conventionally known silicon semiconductor manufacturing technique.

The plate electrodes 101a to 101b are similarly formed on the side of the recording medium facing the multi-probe array head, as shown in FIG. As the recording medium, a recording medium formed of a material having a memory effect on switching characteristics of voltage and current on a support substrate is used. Here C
The substrate obtained by epitaxially growing a Au on a flat substrate of aF ₂ such single crystal as the base electrode, squarylium by LB method - those obtained by accumulating two-layer monomolecular film on the electrode substrate of the bis-6-octyl azulene molecules Used as a recording medium.

FIG. 2 schematically shows, on an enlarged scale, the electrode patterns of the plate electrodes 101a to 101b common to the multi-probe array head and the recording medium. Although this electrode pattern has a comb-shaped electrode structure, the strip-shaped electrode width is not unitary but has two types of widths, which are periodically arranged. The electrode widths need not necessarily be two types, and may be continuously changing as shown in FIG. Here, an electrode pattern as shown in FIG. 2 was used. The interval between the electrodes is 3 μm, and the electrode widths are 9 μm and 30 μm.
They were arranged at a period of 20 μm. The electrode length of the strip is 2
It was set to 00 μm.

FIG. 4 shows a block diagram of an information processing apparatus using the multi-probe array head as described above.
101 is a flat plate electrode for detecting capacitance used for positioning, 401 is a recording medium, 402 is a base electrode, 403 is a substrate for a recording medium, and 404 is a Z for adjusting the distance between the multi-probe array head and the recording medium. Directional drive mechanism,
405 is an XY direction drive mechanism, 406 is a Z direction drive circuit,
407 is an XY direction drive circuit, 408 is a capacitance detection circuit for detecting the capacitance from the probe electrode and the plate electrode 101 provided on the recording medium, and 409 is for automatically controlling the positions of the probe electrode and the recording medium 401. Servo circuit, 410
Is a positioning circuit for determining the position of the probe electrode or the recording medium 401, 411 is a position detection circuit, 412 is a control circuit for centrally controlling the interaction between each block in the apparatus, 41
Reference numeral 3 denotes a tunnel current detection circuit, 414 a write / read circuit for writing / reading write / read information according to an instruction from the control circuit 412, and 415 applying a pulse voltage for writing between the probe electrode and the base electrode 402. A bias circuit 416 for writing data and applying a reading voltage is an interface for inputting / outputting write / read information, inputting a control signal, outputting an address signal, and the like.

Next, the operation of this embodiment will be described.

A current flowing between the probe electrode 104 and the recording medium 401 to which a bias voltage is applied is detected by a tunnel current detection circuit 413, and a positioning circuit 410 and a Z-direction drive circuit are used to keep the current constant. 4
06 and the probe electrode 10 via the Z-direction drive mechanism.
The distance between the recording medium 401 and the surface of the recording medium 401 is feedback controlled. Further, the probe electrode 104 is placed on the surface of the recording medium 401 by XY.
XY direction drive mechanism 405 by the output of drive circuit 407
Drive with The position of the probe electrode in the X and Y directions with respect to the recording medium is detected by a position detection circuit 411, and the detection output is output together with the output of the control circuit 412 and the positioning circuit 410.
The servo circuit 409 is also output as a positioning signal, and the output of the servo circuit 409 is output to the XY direction drive circuit 407. On the other hand, the capacitance between the X- and Y-direction plate electrodes 101 of the comb structure provided on the multi-probe array head and the recording medium respectively changes according to the movement in the XY directions. And is output to the control circuit 412.

Positioning in such an information processing apparatus is performed as follows. First, the probe electrode 104 and the recording medium 4
In order to approach 01, the probe is approached to a desired position by monitoring the tunnel current detected from the probe electrode as a position signal using the Z-direction drive mechanism 404.

Next, the recording medium 401 is scanned at 0.1 Hz in the X direction by the XY direction driving mechanism 405. At this time, the capacitance of the flat plate electrode 101 is different from that of the probe electrode 104 because strip-shaped electrodes having different widths are periodically arranged.
It changes periodically depending on the area where the electrodes of the recording medium 401 and the recording medium 401 overlap. The longest period (in this case, 120 μm) of the signal component of the capacitance change is detected, and the coarse position is adjusted by obtaining the wave height position.

Similarly, fine adjustment is performed by sequentially detecting short-period components in accordance with the strip electrode pattern of the flat plate electrode 101 and obtaining the peak position. The same applies to the Y direction. Here, the alignment was performed alternately in the X and Y directions from coarse adjustment to fine adjustment. Thereafter, focusing on an arbitrary probe electrode 104, a peak value of 4 V and a pulse width of 0.1 μs
And record. When returning to the same crest position as when recording after scanning in the XY directions, the recording medium 401 corresponding to an increase of about one digit in terms of current value
A change in the information on the surface, that is, reproduction was confirmed.

As described above, the scanning surface can be positioned even when recording and reproduction are repeated, and no crosstalk was observed during recording and reproduction.

[0031]

As described above, according to the present invention,
The scanning surface can be positioned with a high degree of accuracy by using one type of plate electrode for detecting capacitance, whereby a margin can be given to the wiring pattern on the probe electrode side, and the occurrence of crosstalk can be suppressed.

[Brief description of the drawings]

FIG. 1 shows a layout diagram of a multi-probe array head section of an information processing apparatus according to the present invention.

FIG. 2 shows a pattern of a flat electrode of the information processing apparatus according to the present invention.

FIG. 3 shows another example of a plate electrode.

FIG. 4 shows a block diagram of an information processing apparatus according to the present invention.

FIG. 5 shows a perspective view of a probe unit.

[Explanation of symbols]

 101a to 101b Capacitance detection plate electrodes 102a to 102b Capacitance detection circuit unit 103 Guard electrode 104 Probe electrode 105 Piezoelectric bimorph cantilever 106 Probe unit 107 Wiring bonding pad 108 Silicon substrate 401 Recording medium 402 Base electrode 403 Recording medium substrate 404 Z-direction drive mechanism 405 XY-direction drive mechanism 406 Z-direction drive circuit 407 XY-direction drive circuit 408 Capacitance detection circuit 409 Servo circuit 410 Positioning circuit 411 Position detection circuit 412 Control circuit 413 Tunnel current detection circuit 414 Write / read circuit 415 Bias Circuit 416 Interface 501 Electrode 502 Piezoelectric layer 503 Electrode 504 Piezoelectric layer 505 Electrode

──────────────────────────────────────────────────続 き Continued on front page (72) Inventor Takehiko Kawasaki 3-30-2 Shimomaruko, Ota-ku, Tokyo Inside Canon Inc. (72) Inventor Haruki Kawasaki 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon (56) References JP-A-4-98633 (JP, A) JP-A-5-109131 (JP, A) JP-A-53-73154 (JP, A) (58) Fields investigated (Int. Cl. ^6, DB name) G11B 9/00 G01B 7/00

Claims (4)

(57) [Claims] 1. A probe is brought close to a recording medium and is scanned in parallel with the recording medium. Information is read out as a fine signal obtained from a physical phenomenon generated at that time, and information is recorded and reproduced on the recording medium. In the information processing apparatus, a plurality of plate electrodes provided independently of the probe and the recording medium on each of the probe side and the recording medium, and capacitance detecting means for detecting a capacitance between these opposed electrodes; Wherein each of the plurality of plate electrodes has the same comb-shaped electrode structure.
An information processing apparatus having a dimensional pattern, wherein the pattern comprises a plurality of spatial frequency components. 2. The information processing apparatus according to claim 1, wherein the minute signal is a tunnel current. 3. The probe and the probe-side plate electrode are provided on the same substrate, and the recording medium and the recording medium-side plate electrode are provided on the same substrate.
Or the information processing apparatus according to 2. 4. The information processing apparatus according to claim 3, wherein a guard electrode is provided around each of the plate electrodes.