JPH06251434A - Information processor - Google Patents

Abstract

PURPOSE:To suppress the generation of crosstalk by forming respective planar electrodes having two-dimensional patterns of the same comb-type electrode structure and composing the pattern of plural spacial frequency components. CONSTITUTION:A probe electrode is driven on the surface of a recording medium 401 by means of a driving mechanism 405 in the XY-directions by using the output of an XY driving circuit 407. The position of the probe electrode in the XY directions to a recording medium is detected by a position detecting circuit 411, the detected output is processed in a positioning circuit 410 together with the output of a control circuit 412 and the output of a servo circuit 409 is outputted to the XY direction driving circuit 407. On the other hand, the capacitance between the planar electrodes 101 in X and Y directions of a comb- type structure provided on a probe array head and a recording medium, respectively, changes in accordance with the movement in the X and Y directions, is detected by a capacitance detecting circuit 408 and outputted to the control circuit 412.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus which scans a probe in the vicinity of a recording medium and records and reproduces information by a physical interaction between the recording medium and the probe, and more particularly, the principle of STM or AFM. 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 STM) that can directly observe the electronic structure of surface atoms of a conductor.
Abbreviated) (G. Binnig et. Al., Phys. Rev.
Lett., 49 (1982) 57), whether it is a single crystal or an amorphous material, it has become possible to measure real space images with a remarkably high resolution of nm or less. Such an STM observes the surface state of the sample by utilizing the fact that a tunnel current flows when a voltage is applied between the metal probe (probe) and the conductive sample so that the distance between them approaches 1 nm. is there. This current is very sensitive to changes in the distance between the two, and either 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 change in current over time, the surface state of the sample can be known with atomic order resolution.

Although analysis using STM is limited to conductive materials, it has also begun to be applied to structural analysis of insulating films thinly formed on the surface of conductive materials. Also, with the development of STM technology, a technique has been proposed in which the surface state is measured by scanning the sample while detecting various physical interactions that occur between the probe and the sample that are extremely close to each other and are not limited to tunnel current. Has been done. In addition to having a high spatial resolution, such devices and means use a method of detecting a minute signal such as a tunnel current, and therefore have the advantage that they can be observed with low power without damaging the sample. Have. Further, since it can be operated in the atmosphere, it is expected to have a wide range of applications.

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, atomic particles adsorbed on the surface of a recording medium by an electron beam or the like are removed to write data. Do S
This data is reproduced by TM.

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

Further, an apparatus for forming a plurality of probe electrodes on a semiconductor substrate for the purpose of miniaturization and displacing a recording medium opposed thereto for recording is disclosed in Japanese Patent Laid-Open No. 62-281138.
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, and a recording medium facing them is attached to a cylindrical piezoelectric element to cause circular motion. By doing so, recording and reproduction are performed.

When accessing a recording medium 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. Normally, 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 the surface of the recording medium is scanned and recorded and reproduced by using the probe head, the probe head and the recording medium must be aligned in the in-plane direction of the recording medium.

If the alignment in the in-plane direction is not performed, the direction to be recorded on the surface of the recording medium and the scanning direction of the probe electrode do not match, causing various problems.

As the positioning means used for this purpose,
There is a method in which a capacitance pad for position detection is provided to detect a capacitance change. In this method, a flat plate electrode is provided in the vicinity of the recording medium and in the vicinity of the probe electrode, and the 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, two directions, that is, the X direction and the Y direction are determined, so that at least two pairs of capacitance pads are required. The shape of the capacitance pad is rectangular, circular, comb-shaped electrode, or the like. Further, when actually performing the alignment, it is difficult to perform the alignment with high accuracy suddenly. 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 for highly accurate alignment.

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 using the semiconductor manufacturing process technology. A piezoelectric bimorph cantilever 105, which is a tongue-like fine movement mechanism, is cantilevered on a single crystal silicon substrate 108.
A probe electrode 104 is formed on the free end of the piezoelectric bimorph cantilever 105 to form a probe unit 106. The piezoelectric bimorph cantilever 105 has a layered structure, and the electrode 50 is arranged from the silicon substrate 108 side.
1, piezoelectric layer 5002, electrode 503, piezoelectric layer 504,
An extraction electrode 506 is attached to each of the electrodes 501, 503, and 505, which is laminated with the electrode 505.
When a voltage is applied to the electrodes 501, 503, 505 from the extraction electrode 506, the piezoelectric layers 502, 504 expand and contract, so that the probe electrode 104 is parallel to the direction perpendicular to the surface of the silicon substrate 108 (Z direction) or the surface of the silicon substrate 108. It can be freely displaced in various XY directions. The multi-probe array head is formed on the silicon substrate 108 by integrating a large number of such probe units 106. A part of the drive circuit for these probe units 106 is also provided on the silicon substrate 108.

As described above, many elements are formed in the multi-probe array head, but as shown in FIG. 5, only one probe unit 106 requires seven wires. As such, the routing of the wiring requires a lot of area on the board, and a couple of pairs of capacitance pads for position detection and the wiring are added to this, and thus the wiring becomes more dense. . For this reason, crosstalk occurs between wirings, and particularly when detecting a minute current such as a tunnel current, such noise significantly impairs the reliability of the device.

[0015]

In a conventional multi-probe array head, coarse adjustment and fine adjustment capacitance pads and a plurality of probe units are arranged, and the wiring intervals thereof are close. Therefore, there is a problem in that crosstalk is likely to occur between the wirings and the reliability of the device is impaired. This is especially true for capacitive pads,
Because the area occupied in the multi-probe array head is large, it requires 2 pairs for the X direction and Y direction for the alignment, and 2 pairs for each of the coarse adjustment and the fine adjustment. The main cause 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 the capacitance pads and allowing a sufficient wiring interval in the multi-probe array head.

[0017]

In order to achieve the above object, an information processing apparatus according to the present invention is arranged so that a probe is brought close to a recording medium and scanning is performed in parallel with the recording medium. A plurality of flat plate electrodes provided independently of the probe and the recording medium on each of the probe side and the recording medium as an information processing device for reading information as a fine signal to be obtained and recording and reproducing the information on the recording medium. And a capacitance detecting means for detecting a capacitance between these electrodes, wherein the plurality of flat plate electrodes each have a two-dimensional pattern of the same comb-shaped electrode structure, and Is composed of a plurality of spatial frequency components.

[0018]

In the information processing apparatus having the above configuration, the capacitance pads provided on the probe side and the recording medium side can generate signals for rough adjustment and fine adjustment with one pattern.
Therefore, the wiring space on the substrate on the probe side does not become close, and crosstalk does not occur.

[0019]

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

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

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

The plate electrodes 101a to 101b are similarly formed on the recording medium side facing the multi-probe array head as shown in FIG. As the recording medium, a material having a memory effect on the switching characteristics of voltage and current formed on a supporting substrate is used. Here C
A substrate obtained by epitaxially growing Au on a flat single crystal substrate such as aF _{2 is used} as a base electrode, and two monolayers of squarylium-bis-6-octylazulene molecular monolayers are accumulated on the electrode substrate by the LB method. It is used as a recording medium.

FIG. 2 schematically shows an enlarged electrode pattern of the flat 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 single but has two types of widths, which are arranged periodically. The electrode width does not necessarily have to be two types, and may continuously change as shown in FIG. Here, an electrode pattern as shown in FIG. 2 was used. The distance between the electrodes is 3 μm, and the electrode width is 9 μm and 30 μm.
It was arranged in a cycle of 20 μm. The strip-shaped electrode length 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 electrostatic capacitance used for positioning, 401 is a recording medium, 402 is a base electrode, 403 is a substrate for recording medium, 404 is 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,
Reference numeral 407 is an XY direction drive circuit, 408 is a capacitance detection circuit for detecting capacitance from the probe electrode and the flat 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 that determines the positions of the probe electrodes and the recording medium 401, 411 is a position detection circuit, 412 is a control circuit that performs centralized control of interaction between blocks in the apparatus, 41
3 is a tunnel current detection circuit, 414 is a write / read circuit for writing / reading write / read information according to an instruction from the control circuit 412, and 415 is a pulse voltage for writing applied between the probe electrode and the base electrode 402. A bias circuit 416 for writing data or applying a read 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 tunnel current detection circuit 413 detects a current flowing between the probe electrode 104 and the recording medium 401, to which a bias voltage is applied, and the positioning circuit 410 and the Z direction drive circuit keep the current constant. Four
06, and the probe electrode 10 via the Z-direction drive mechanism.
The distance between the recording medium 4 and the surface of the recording medium 401 is feedback-controlled. In addition, the probe electrode 104 is placed on the surface of the recording medium 401 in XY
The XY driving mechanism 405 is controlled by the output of the driving circuit 407.
Drive with. The position of the probe electrode in the XY directions with respect to the recording medium is detected by the position detection circuit 411, and the detection output thereof 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 electrostatic capacitance between the X and Y direction flat 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, which is the electrostatic capacitance detection circuit 408. Is detected by the control circuit 412 and 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 bring 01 closer, the Z-direction drive mechanism 404 is used to monitor the tunnel current detected from the probe electrode as a position signal to bring the probe closer to a desired position.

Next, the recording medium 401 is scanned in the X direction at 0.1 Hz by the XY driving mechanism 405. At this time, the capacitance of the flat plate electrode 101 is such that the strip-shaped electrodes having different widths are periodically arrayed, so that the probe electrode 104
Changes periodically depending on the area where the electrodes on the side of the recording medium 401 and the electrodes on the side of the recording medium 401 overlap. Coarse adjustment is performed by detecting the longest period (here, 120 μm) of the signal component of the capacitance change and 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 determining the wave height position. The same applies to the Y direction. Here, the X direction and the Y direction are alternately aligned from the coarse adjustment to the fine adjustment. Then, paying attention to an arbitrary probe electrode 104, the peak value is 4 V and the pulse width is 0.1 μs.
Apply pulse voltage of and record. A recording medium 401 corresponding to an increase of about one digit in terms of current value when returning to the same wave height position as when recording after scanning in the XY directions
It was confirmed that the information on the surface of the was changed or reproduced.

As described above, the scanning plane can be positioned even if the recording / reproducing is repeated, and no crosstalk was observed during the recording / reproducing.

[0031]

As described above, according to the present invention,
Positioning of the scanning surface can be performed with high precision by one type of electrostatic capacitance detection flat plate electrode, so that a margin can be provided in the wiring pattern on the probe electrode side, and the occurrence of crosstalk can be suppressed.

[Brief description of drawings]

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

FIG. 2 shows a pattern of flat plate electrodes 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 flat plate electrodes 102a to 102b Capacitance detection circuit section 103 Guard electrode 104 Probe electrode 105 Piezoelectric bimorph cantilever 106 Probe unit 107 Wiring extraction 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

 ─────────────────────────────────────────────────── ─── Continued Front Page (72) Inventor Takehiko Kawasaki 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (72) Inventor Haruki Kawada 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Within the corporation

Claims (4)

[Claims] 1. A probe is brought close to a recording medium to scan in parallel with the recording medium, information is read out as a fine signal obtained from a physical phenomenon occurring at that time, and information is recorded / reproduced on / from the recording medium. In the information processing apparatus, a plurality of flat plate electrodes provided independently of the probe and the recording medium on the probe side and the recording medium, and a capacitance detecting means for detecting a capacitance between the electrodes facing each other. And the plurality of flat plate electrodes each have the same comb-shaped electrode structure.
An information processing apparatus having a three-dimensional pattern, wherein the pattern is composed of a plurality of spatial frequency components. 2. The information processing apparatus according to claim 1, wherein the fine signal is a tunnel current. 3. The probe and the flat plate electrode on the probe side are provided on the same substrate, and the recording medium and the flat plate electrode on the recording medium side are provided on the same substrate.
Or the information processing device according to 2. 4. The information processing apparatus according to claim 3, wherein guard electrodes are provided around the flat plate electrodes.