JP3029503B2 - Recording method and information processing apparatus - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an information processing apparatus to which a scanning tunnel microscope is applied.

[0002]

2. Description of the Related Art In recent years, a scanning tunneling microscope (hereinafter referred to as an STM) that allows a probe and a sample to approach each other, and directly observes the electronic structure near and on the surface of a material by utilizing a physical phenomenon (tunnel phenomenon or the like) generated at that time. [G.Bi]
nnig et al., Helvetica Physica Acta, 55,726 (198
2)], real space images can be measured with high resolution regardless of whether they are single crystals or amorphous. STM also has the advantage that it can be observed at low power without damaging the medium due to electric current. Furthermore, it can operate not only in ultra-high vacuum but also in air and solutions, and can be used for various materials. It is expected to have a wide range of applications in academic and research fields.

The STM utilizes a tunnel current that flows when a voltage is applied between a metal probe (probe electrode) and a conductive material and the distance is reduced to about 1 nm. The amount of the tunnel current changes very sensitively depending on the distance change between the two. Therefore, by scanning the probe so as to keep the tunnel current constant, it is possible to read various information on all electron clouds in the real space. The resolution in the in-plane direction at this time is about 0.1 nm.

[0004] Therefore, if the principle of STM is applied, it is possible to perform high-density recording / reproducing on the order of atoms (sub-nanometer). For example, JP
In the information processing apparatus disclosed in Japanese Patent Application Laid-Open No. 1-80536, writing is performed by removing atomic particles adsorbed on the medium surface by an electron beam or the like, and the data is reproduced by STM.

Further, as disclosed in US Pat. No. 4,575,822, charges are applied to a dielectric layer formed on the surface of a recording medium by using a tunnel current flowing between the surface of the recording medium and a probe electrode. A method of recording by injection and recording, or recording by physical or magnetic collapse of the medium surface using a laser beam, an electron beam, a particle beam or the like has also been proposed.

A method in which recording and reproduction are performed by STM using a recording medium having a memory effect on the switching characteristics of voltage and current as a recording layer, for example, a thin film layer of a π-electron organic compound or a chalcogen compound, is disclosed in Japanese Patent Application Laid-Open Publication No. H10-157,197. 63-16155
No. 2 and JP-A-63-161553. According to these methods, assuming that the recording bit size is 10 nm, large-capacity recording and reproduction of 10 ¹² bit / cm ² is possible.

In the information processing apparatus as described above, in order to perform recording and reproduction on a recording medium, positioning called so-called tracking based on a predetermined standard, for example, a groove or the like provided on the surface of the recording medium is performed. An information processing device for performing the processing is required.

[0008] In the case of an information processing apparatus that performs recording and reproduction at a very high density to which the STM is applied, generally, the probe is scanned while the above-described tracking is performed, and an information bit string is written line by line.

In addition, when writing an information bit string, it is necessary to control the distance between a probe serving as a pickup for recording at the time of recording and the recording medium. JP-A-1-13
In Japanese Patent No. 3239, a recording method has been proposed which employs a distance control method in which "the average value of the current at the time before increasing the current for recording is held as a reference" during recording.

[0010]

In the case of the above-described information processing device having a very high density, due to the nature of its use,
There is a tendency that a large capacity and a high transfer rate are required.

However, in a conventional general recording / reproducing method,
Using the tunnel current that flows in the same way as the STM principle,
A method is employed in which a probe electrode is scanned in the XY directions (horizontal direction on the surface of the recording medium), and at the same time, a recording voltage is applied in accordance with the recording information and recording bits are written while performing tracking by detecting irregularities on the surface of the recording medium. .

For this reason, it is necessary to simultaneously execute the feedback of detecting the tunnel current flowing between the recording medium and the probe electrode and keeping the distance between the probe electrode and the probe electrode constant so as to keep the distance therebetween constant. Since the time required for the reciprocal scanning of the probe in the ON state is long, there is a problem in that the transfer rate of recording and reproduction is reduced.

For example, when recording is performed while repeating sample / hold (S / H) of the distance control signal as in the method disclosed in the above-mentioned Japanese Patent Application Laid-Open No. 1-133239, the search is performed during the hold. Between writing one bit and writing the next bit so that the needle does not collide with the recording medium, it is necessary to wait until the distance between the probe and the recording medium becomes constant by height control using a distance control signal. is there. As described above, the recording speed is limited by the response frequency of the height control.

Further, since the distance between the recording medium and the probe electrode is controlled by applying feedback by the tunnel current, it is necessary to perform recording while setting the distance between the two to be short enough to allow the tunnel current to flow. Depending on the recording medium, the optimum distance for recording and the distance may be different. In this case, the actual record may be disturbed,
Had been a problem.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems of the prior art, and provides a recording method capable of increasing a transfer rate and an information processing apparatus using the recording method. With the goal.

[0016]

According to the present invention, there is provided a recording method comprising :
The probe electrode arranged opposite to the recording medium
The medium is scanned and information is stored between the probe electrode and the recording medium.
Information by applying a modulated voltage
A method of recording, before the said probe electrode
The same area of the recording medium is reciprocally scanned, and irregularities on the surface of the recording medium are detected at the time of forward scanning , and the detected irregularity information is stored.
Advance, while changing the distance between the flop <br/> probe electrode and the recording medium in accordance with said stored concave-convex information during the backward scanning, 該Pu
Information is recorded by the lobe electrode .

In this case, the stored unevenness information is turned off.
When the probe electrode is re-scanned, this set
The distance between the probe electrode and the recording medium may be changed according to the unevenness information to which the offset has been added .

The information processing apparatus of the present invention faces a recording medium.
And a probe electrode arranged as
Scanning means for scanning a recording medium, and the probe electrode
Unevenness detecting means for detecting unevenness of the surface of a recording medium to be scanned
And a professional according to the unevenness information detected by the unevenness detecting means.
Irregular response drive that changes the distance between the probe electrode and the recording medium
Mechanism and information between the probe electrode and the recording medium.
Information by applying a modulated voltage
An information processing apparatus having a power supply for performing the processing, comprising: a storage device for storing the unevenness information;
The same area of the recording medium is reciprocally scanned by the
And the irregularity information detected by the detection means during forward scanning is recorded.
In the storage device, and the concave portion stored in the storage device at the time of rescanning.
Reads the convex information, and reads the convex information
The distance between the probe electrode and the recording medium is changed by the
And record information with the probe electrode.
You .

In this case, the recess read from the storage unit is used.
An offset adder that adds an offset to the convex information,
The concave / convex driving mechanism operates the concave / convex information to which the offset is added.
The distance between the probe electrode and the recording medium according to the
It may be good .

Further, the memory device is FILO type memory mechanism
It may be to consist of.

[0021]

According to the present invention, when printing is performed, the same area of the printing medium is scanned twice, and in the second scanning in which printing is actually performed, the printing medium detected during the first scanning is used. Recording is performed in a state where the distance between the probe electrode and the recording medium changes according to the surface irregularities. As described above, since it is not necessary to perform feedback control of the distance between the probe electrode and the recording medium during recording, the transfer rate of the recording data can be increased.

Further, by changing the distance between the probe electrode and the recording medium by adding an offset, the distance between the probe electrode and the recording medium when detecting irregularities and the distance between the probe electrode and the recording medium when recording are performed. The distance can be set to an optimum distance.

Further, if the surface unevenness storage device for storing surface unevenness information is constituted by a FILO type storage mechanism, the distance between the probe electrode and the recording medium may be changed in the order of data read from the storage mechanism. The device configuration is simplified.

[0024]

[0025]

Next, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a block diagram showing the configuration of one embodiment of the present invention.

In FIG. 1, reference numeral 101 denotes a probe electrode for performing recording and reproduction on a recording medium.
Then, by applying a voltage to a recording medium placed on the XY stage 102, formation or reading (recording / reproduction) of recording bits is performed.

The recording medium is composed of a substrate 121, a substrate electrode 122 laminated on the substrate 121, and a recording layer 123. A recording bit 124 is formed on the recording layer 123 by applying a voltage from the probe electrode 101. You.

Reference numeral 103 denotes the probe electrode 101 and the substrate electrode 1
A probe current amplifier for amplifying the current flowing between 22;
Reference numeral 105 denotes a Z-direction fine movement control mechanism using a piezoelectric element for adjusting the height of the probe electrode 101. Reference numeral 104 denotes a Z direction in which the probe current is read to control the height adjustment of the probe electrode 101 by the Z-direction fine movement control mechanism 105. Drive circuit,
Reference numeral 106 denotes a power supply for applying a bias voltage for reproduction or a pulse voltage for recording / erasing between the probe electrode 101 and the substrate electrode 102. In the case of the apparatus according to the present invention, since the feedback in the Z direction is turned off at the time of recording, the HOLD circuit in the Z direction driving circuit required at the time of recording, which is conventionally required, becomes unnecessary.

Reference numeral 108 denotes an XY direction fine movement control mechanism for controlling the movement of the probe electrode 101 in the XY directions.
An XY scanning drive circuit for driving the Y-direction fine movement control mechanism 108. 109 and 110 are 10
The distance between the probe electrode and the recording medium is coarsely controlled so that a probe current of about ^-9 A can be obtained.
A coarse movement mechanism and a coarse drive circuit used to increase the relative displacement between the X.01 and the recording medium in the X and Y directions (outside the range of the fine movement control mechanism).

Reference numerals 113 and 114 denote a surface unevenness storage device and an unevenness response driving device, which are the most characteristic components of the present invention. The unevenness of the surface of the recording medium detected in the forward scan, which is the first scan of the probe electrode 101, is stored by the surface unevenness storage unit 113, and the unevenness response drive unit 114 performs the second scan in the return scan according to the unevenness information. Power supply 106 while controlling the vertical movement of probe electrode 101
The recording is performed by applying the recording voltage from. Reference numeral 112 denotes a display element, which displays a state of formation of the recording bit 124, recording information reproduced by the recording bit 124, and the like.

The operation of each of these devices is centrally controlled by the microcomputer 111.

Next, a recording method according to this embodiment will be described with reference to FIG.

When recording, the probe electrode 101 is reciprocally scanned with respect to the same scanning area of the recording medium. On the outward path, as shown in FIG. 2A, the probe electrode 101 is scanned from the left end position to the right direction in the drawing with feedback in the Z direction (vertical direction in the drawing) by the tunnel current to remove irregularities on the surface of the recording medium. It is detected and stored in the surface unevenness storage unit 113.

When the probe electrode 101 reaches the right end and the storage of the surface irregularities for one row of the scanning area is completed, the operation proceeds to the recording operation. In this recording operation, after the feedback in the Z direction is turned off, as shown in FIG. 2B, the probe electrode 101 is moved up and down according to the irregularity information of the recording medium surface stored in the surface irregularity storage unit 113 on the outward path. Scan leftward while moving. In this return path, by applying a recording voltage or the like in accordance with the recording information to cause a change in conductivity or the like in the recording layer, a recording bit 124 is formed and recording is performed.

However, in this case, since the scanning direction at the time of detecting the unevenness information on the surface of the recording medium is opposite to the scanning direction at the time of recording, the vertical movement of the probe electrode 101 is adjusted so as to match the unevenness of the surface of the recording medium. The information from the unit 113 has been converted. If the scanning directions at the time of recording and at the time of reproduction are opposite, processing has been performed on the recording information in advance.

Thus, in this embodiment,
On the return path, recording is performed without feedback in the Z direction, so that the scanning speed of the probe electrode 101 can be increased, so that the transfer rate during recording can be increased.

FIG. 3 is a block diagram showing the configuration of the second embodiment of the present invention.

In this embodiment, an offset adder 315 for adding an offset to the surface unevenness information stored in the surface unevenness storage unit 113 is added. Other configurations are the same as those of the embodiment shown in FIG. .

By providing the offset adder 315, the probe electrode 1 in the return path of the probe electrode 101
01. The distance between the recording media can be maintained at a desired value, and the recording can be executed in an optimal state.

The mechanical performance in the movement control using the piezoelectric element used in each of the above embodiments is shown below.

Z direction fine movement control range: 0.1 nm to 1 μm Z direction coarse movement control range: 10 nm to 10 mm XY direction scanning range: 0.1 nm to 1 μm XY direction coarse movement control range: 10 nm to 10 mm Measurement and control tolerance: <0.1 nm (at the time of fine movement control) Measurement and control tolerance: <1 nm (at the time of coarse movement control) Hereinafter, a specific experimental example according to the above embodiment will be described.

[Experimental Example 1] An optically polished glass substrate (substrate 121) was washed with a neutral detergent and trichlene (trichloroethylene), and then Cr was formed as a subbing layer to a thickness of 50 mm by a vacuum deposition (resistance heating) method. Then, Au was deposited at 1000 ° by the same method, and the substrate electrode 122 was deposited.
Was formed.

Next, squarylium-bis-6-octylazulene (hereinafter abbreviated as SOAZ) was added at a concentration of 0.2 mg / m 2.
The chloroform solution dissolved in 1 was spread on an aqueous phase at 20 ° C. to form a monomolecular film on the water surface. Wait for the solvent to evaporate,
The surface pressure of the monomolecular film was increased to 20 mN / m, and the electrode substrate was gently immersed at a speed of 5 mm / min across the water surface while keeping the surface pressure constant. Next, this is pulled up, two Y-type monomolecular films are accumulated, and a two-layer accumulated film (LB film) is formed on the substrate electrode.
23. With such a configuration, the current-
This is a recording medium in which a memory switching phenomenon (electric memory effect) occurs in the voltage characteristics.

In the electric memory effect, a voltage exceeding a threshold value capable of transitioning to two different states is applied in a state in which a thin film such as an organic monomolecular film or its cumulative film is arranged between a pair of electrodes. This means reversibly making a transition (switching) between a low resistance state (ON state) and a high resistance state (OFF state) and holding (memory) the state.

A recording / reproducing experiment was performed on the recording medium prepared by the above method using the information processing apparatus shown in FIG. However, a platinum / rhodium probe electrode formed by an electrolytic polishing method is used as the probe electrode 101, and the distance (Z) of the probe electrode 101 is set by a piezoelectric element so that a voltage can be applied to the recording layer 123. Is controlled. Further, a fine movement control mechanism system is provided so that the probe electrode 101 can be controlled to move in the in-plane (X, Y) direction while having the above functions.

The probe electrode 101 can directly perform recording and reproduction. The recording medium is placed on the high-precision XY stage 102 and can be moved to any position. Therefore, recording and reproduction can be performed at an arbitrary position by the probe electrode 101 by this movement control mechanism.

Recording layer 1 in which two SOAZ layers are accumulated.
The recording medium having 23 was set in the information processing apparatus. Next, a voltage of +1.5 V is applied between the probe electrode 101 and the substrate electrode 122 of the recording medium, and while monitoring the current flowing through the recording layer 123, the distance (Z) between the probe electrode 101 and the substrate electrode 122 is determined. It was adjusted. At this time, the probe current I _p for controlling the distance Z between the probe electrode 101 and the substrate electrode 122 was set to be 10 ⁻⁸ A ≧ I _p ≧ 10 ⁻¹⁰ A. Next, while keeping the distance Z between the probe electrode 101 and the substrate electrode 122 constant, the probe electrode 10
1 was moved in the −X direction (see FIG. 2) and moved to the left end of the recording area.

Next, the probe electrode 101 was scanned in the right direction by applying feedback in the Z direction by a tunnel current. In the forward path, the unevenness of the surface of the recording medium is detected, and the detected unevenness information is stored in the surface unevenness storage unit 113.

Next, after the probe electrode 101 reaches the right end and the surface unevenness for one row of the scanning area is stored, the feedback in the Z direction is turned off, and the recording medium stored in the surface unevenness storage unit 113 in the outward path. Scanning was performed in the left direction at twice the speed of the outward path while moving the probe electrode 101 up and down according to the surface unevenness information.

In this return path, information was recorded at a pitch of 200 °. The recording of such information is performed by the probe electrode 1.
A triangular wave pulse as shown in FIG. 4 so that the electrical memory material (two layers of SOAZ-LB film) as a recording medium changes to a low resistance state (ON state) with 01 as the + side and the substrate electrode 122 as the − side. A voltage was applied. At this time, since the scanning direction at the time of detecting the unevenness information of the recording medium surface and the scanning direction at the time of recording are opposite, the position information from the surface unevenness storage unit 113 is adjusted so that the unevenness of the recording medium surface and the vertical movement of the probe electrode 101 coincide. (X direction) has been converted. Further, in the apparatus used in this embodiment, since the scanning directions at the time of recording and at the time of reproduction are opposite to each other, the recording information is processed in advance so that the recording bit string is reversed.

Thereafter, the probe electrode 101 and the substrate electrode 1
While applying a read bias voltage of +1.5 V during the period 22, the recorded information written earlier was read.
At this time, the point at which the recording triangular pulse voltage was applied was 0.1 mm.
A probe current of about 7 mA flows, changes to the ON state, that is, is recorded, and information to be recorded is accurately recorded over the entire recording / reproducing unit.
It was shown that recording was possible even if the recording speed was doubled.

That is, it has been proved that the recording / reproducing method of the present invention and the information processing apparatus using the same can increase the transfer rate during recording.

The thickness per SOAZ layer was about 15 ° as determined by small-angle X-ray diffraction.

[Experimental Example 2] A substrate electrode 122 was formed on a glass substrate 121 in the same manner as in Experimental Example 1, and then a recording layer 123 formed by accumulating two polyimide LB films was formed to obtain a recording medium. The method for forming the polyimide LB film is as follows.

A dimethylacetamide solution in which polyamic acid (molecular weight: about 200,000) was dissolved at a concentration of 1 × 10 ⁻³ % (g / g) was spread on an aqueous phase of pure water at a water temperature of 20 ° C. A molecular film was formed. The surface pressure of this monolayer is 25 m
The substrate was moved at a rate of 5 mm / min so as to traverse the water surface at a rate of 5 mm / min, immersed and pulled up, and the Y-type monomolecular film was accumulated. next,
These films were heated at 300 ° C. for 10 minutes to obtain polyimide. The thickness per polyimide layer was determined to be about 4 ° by ellipsometry.

With respect to the recording medium prepared by the above method, a recording / reproducing experiment was performed in exactly the same manner as in Experimental Example 1 except that the scanning speed of the probe electrode 101 in the return path was tripled to increase the recording speed. However, accurate recording was performed over the entire recording / reproducing unit, and it was confirmed that the transfer rate at the time of recording could be increased according to the method and apparatus of the present invention.

Next, a second embodiment of the present invention will be described.

[Experimental Example 3] On a glass substrate (substrate 121) that had been optically polished, a Cr undercoat layer having a thickness of 50 ° and an Au thin layer having a thickness of 1000 ° were formed by a vacuum evaporation method (resistance heating method). The electrode 122 was used. Next, 300 Å of hydrogen is deposited on the substrate electrode 122 by plasma CVD.
% Amorphous silicon recording layer 103 was laminated. This recording layer was formed under the conditions of a pressure of 0.1 torr and a power of 50 W in the apparatus while maintaining the substrate temperature at 200 ° C. and flowing a mixed gas of SiH ₄ and H ₂ into the 20 SCCM film forming apparatus.

The recording medium created as described above is
Recording and reproduction experiments were performed using the information processing apparatus shown in FIG. However, as the probe electrode 101, a platinum / rhodium probe electrode created by an electrolytic polishing method is used, and most of the drive mechanism and recording mechanism of the probe electrode 101 are equivalent to or larger than the apparatus shown in FIG. Has a function.

The recording layer 123 made of hydrogen-containing amorphous Si
Was set in the information processing apparatus, and the distance between the probe electrode 101 and the recording medium was adjusted as in Experimental Example 1.

Next, the probe electrode 101 and the substrate electrode 12
While keeping the distance Z of 2 constant, the probe electrode 101 was moved in the −X direction (see FIG. 2) and moved to the left end of the recording area.

Next, the probe electrode 101 was scanned in the right direction by applying feedback in the Z direction by a tunnel current. In the outward path, the unevenness of the surface of the recording medium is detected, and the unevenness information is stored in the surface unevenness storage unit 113.

After the probe electrode 101 reaches the right end and the storage of the surface irregularities for one scanning area is completed, the feedback in the Z direction is turned off, and in order to match the optimal recording condition of the recording medium, Unevenness storage device 113
By adding an offset from the offset adder 315 to the unevenness information of the recording medium surface stored in the probe electrode 101, the distance between the probe electrode 101 and the recording medium in the return path of the probe electrode 101 is moved 30 ° away from the outward path to move the probe electrode 101 up and down. While scanning to the left at twice the speed of the outward path. At the same time, information was recorded at a pitch of 200 ° on this return path.

The recording of such information is performed by the probe electrode 101.
With a positive voltage and a substrate electrode 122 with a negative voltage, a pulse voltage having a peak value of 5 volts and a pulse width of 1 μsec was applied so as to cause a change in the hydrogen-containing amorphous Si. However, also in this case, as in Experimental Example 1, since the scanning direction at the time of detecting the unevenness information on the recording medium surface and the scanning direction at the time of recording are opposite, the surface unevenness storage device is set so that the vertical movement of the probe electrode is made to coincide with the surface unevenness. Has been converted (X direction). Also,
In the apparatus used in this experimental example, since the scanning directions at the time of recording and at the time of reproduction are opposite, the recording information is pre-processed so that the recording bit string is reversed.

Thereafter, the probe electrode 101 and the substrate electrode 1
While applying a read bias voltage of +1 V during the period 22, the recorded information written earlier was read. At this time, the portion to which the recording pulse voltage was applied was 10 nm in diameter.
It was found that the recording bits of the order of magnitude were formed stably, and that accurate recording of the recording information was performed. That is, in the conventional general recording method, there was a point that a large variation was observed in the recording bit size and the accuracy at the time of recording was lacking. However, according to the present invention, the transfer rate at the time of recording can be increased, and Accurate recording has become possible under various recording conditions.

In Experimental Example 3 described above, the distance between the recording medium and the probe electrode is increased during recording. However, the distance is not limited to this, and it is important to match the optimum recording conditions of the recording medium. .

The recording layer is not limited to the above-described experimental example as long as the recording layer has an electrical switching memory effect or is capable of electrically exhibiting a state change.
The formation method and the like are not limited to this.

Further, in each embodiment, one probe electrode has been described. However, two or more probe electrodes may be used, such as one for recording / reproducing and one for tracking.

Next, a third embodiment of the present invention will be described.

FIG. 5 is a block diagram showing the configuration of the third embodiment of the present invention.

In this embodiment, similarly to the embodiments shown in FIGS. 1 and 3, the positional relationship between the probe electrode and the recording medium is detected and stored at the time of forward scanning, and the positional relationship stored at the time of backward scanning. The recording is performed by using. FIG. 5 shows a portion for storing the detected positional relationship in detail.

In the figure, 501 is a conductive probe electrode, 5
02 is a cylindrical piezoelectric element which is a fine movement driving mechanism for driving the probe electrode 501 in the Z direction, and 503 is a recording medium.
The cylindrical piezoelectric element 502 is configured to be able to access an arbitrary recording bit string by a coarse driving mechanism such as a linear motor (not shown).

Normally, the probe electrode 501 and the recording medium 50
A bias voltage is applied by the bias circuit 504 during the period 3 and the current is brought close to a level at which a tunnel current or a field emission current flows. This tunnel current or field emission current is input to the Z servo circuit 506 after voltage conversion by the current-voltage conversion circuit 505. The Z servo circuit 506 outputs the distance control signal S3 so that the tunnel current or the field emission current becomes constant. The distance control signal S3 is an electrode 50 which is a drive electrode of the cylindrical piezoelectric element 502.
8 is applied. The probe electrode 501 is formed by mechanically cutting platinum and sharpening it.

As the recording medium 503, JP-A-63-1
A material having an electric memory effect with respect to the switching characteristics of voltage and current as disclosed in JP-A-61552 and JP-A-63-161553 was used. These have basically the same configuration as those used in the respective experimental examples in the first embodiment and the second embodiment. For example, a substrate electrode on a flat substrate such as glass or mica is used as a substrate electrode. An epitaxial growth surface of gold is used. Squarium-bis-6-octylazulene (S
An OAZ) is formed by forming a two-layer monomolecular film on the substrate electrode by the Langmuir-Blodgett method.

The recording in this embodiment is performed as follows.

Normally, the probe electrode 501 and the recording medium 50
Between 3, the bias voltage is applied by the bias circuit 504, and these are brought close to the extent that a tunnel current flows. In this state, the probe electrode 501 is moved to a desired recording position on the recording medium 503, and the bias voltage from the bias circuit 504 is modulated to apply a voltage exceeding the threshold voltage at which the electric memory effect occurs between the probe electrode 501 and the recording medium 503. To record. Actually, a bias voltage of about 0.1 to 1 V by the bias circuit 504 is applied between the probe electrode 501 and the recording medium 503,
It is kept close to the extent that a constant tunnel current (1 pA) flows.

In this state, after the probe electrode 501 is moved between desired recording positions on the recording medium 503, the bias voltage is modulated by the bias circuit 504, and a pulse voltage as shown in FIG. 4 is applied to the probe electrode 501 and the recording medium 503. When a current of about 0.7 mA flows when applied between
A bit of 0 nmφ is formed, and after application of the pulse voltage,
Hold that state. Therefore, the bit in the low resistance state is associated with “1” and is distinguished from “0” in the high resistance state. The encoder 515 adds “0” and “1” to the recording data.
And performs binary recording.

At the time of binarization recording, the probe electrode 501
Performs printing while two-dimensionally scanning an XY raster on the printing medium 503. At this time, at the time of forward scanning of X (+ X direction), the probe electrode 501 for recording the bit “1” is used.
And temporarily store the horizontal and vertical relative positions of the recording medium 503 and then, in the backward scanning (-X direction), turn off the servo in the Z direction and relatively move the probe electrode 501 on the recording medium 503 using the stored information. After the end, the bias circuit 504 was controlled to record a bit corresponding to "1".

A specific recording method in this embodiment will be described with reference to FIG. 6 showing the operation of each unit in FIG.

In this embodiment, during forward scanning (+ X direction), the control circuit 510 uses the switching signal S2 to switch the SW circuit 50.
9 is switched to the A side. Thereby, the probe electrode 50
The Z servo circuit 506 applies a distance control signal S3 corresponding to a detection current of the probe electrode 501 to the electrode 508 to which a control voltage for determining the distance between the probe electrode 501 and the recording medium 503 is applied.
Is applied, and the tunnel current or the field emission current flowing between the probe electrode 501 and the recording medium 503 is kept constant.

As described above, while controlling the height in the Z direction, 1
Scan the raster (n-th raster). At this time, the control circuit 510 determines that the probe electrode 501 is
The bit recording position corresponding to the above "1" (X0, Z in FIG. 6)
(Equivalent to 0), the X-direction scanning signal (X0) of the XY fine movement drive circuit 511 is generated by the control signals S1 and S4.
Is stored in a FILO (First In Last Out) memory 512 (corresponding to the surface unevenness storage unit 113 in FIGS. 1 and 3), and the value (Z0) of the distance control signal S3 at this time is stored.
Is stored in the FILO memory 513.

By repeating this operation at the bit recording position during the forward scan, the FILO memories 512 and 513 store the X-direction scanning signal and the distance control signal S3 for the number of bits corresponding to "1" in one raster. Is done.

At the time of reverse scanning (−X direction) in which the scanning direction of the probe electrode 501 is reversed, the SW circuit 509 is switched to the B side by the switching signal S2 output from the control circuit 510. As a result, the output of the Z drive circuit 514 placed under the control of the control circuit 510 is applied to the electrode 508. In this state, recording bits are formed on the recording medium 503. At this time, the output of the Z servo circuit 506 is
8, the height control of the probe electrode 501 as in the forward scanning is not performed.

That is, at the time of the backward scanning, the probe electrode 501 is moved to the recording position on the recording medium 503 in an open loop according to the data from the two FILO memories 512 and 513.

The drive control of the probe electrode 501 will be described in detail. The control circuit 510 controls the XY fine movement drive circuit 511 based on the value stored in the FILO memory 512, and outputs a signal (for moving the probe electrode 501 in the horizontal direction). The X-direction scanning signals X1 and X0 in FIG. 6 are output. At this time, the output of the Z drive circuit 514 is applied to the electrode 508 via the SW circuit 509. When the probe electrode 501 moves in the horizontal direction, the control circuit 510 tells the Z drive circuit 514 that the probe electrode 501 has sufficient recording medium 503.
And outputs a voltage value Zinit that departs from the initial value. After the horizontal movement is completed, the control circuit 510 outputs the value of the FILO memory 513 to the Z drive circuit 514 (voltage values Z1 and Z0 to the electrode 508) and controls the height direction of the probe electrode 501. In this state, the control circuit 510 controls the bias circuit 50
4 is modulated to generate a pulse voltage, and bit recording corresponding to "1" is performed. After one bit recording is completed, the Z drive circuit 514 outputs Zinit again, separates the probe electrode 501 from the recording medium 503, and moves the probe electrode 5 to the bit recording position stored at the next address of the FILO memory 512.
01 is moved to perform recording.

The control circuit 510 changes the Y-direction scanning signal after all the bits stored in the value of the FILO memory are recorded at the time of the backward scanning (-X direction) as described above to change the probe electrode 501. Move to the next raster (n + 1th raster). At this time, the SW circuit 509 is again set to A
Side, and the forward scan (+ X direction) of the next raster is started while controlling the distance between the probe electrode 501 and the recording medium 503 by the Z servo circuit 506.

According to the present embodiment, the probe electrode 501 and the recording medium 5 for recording at the time of the backward scanning (−X direction).
Since the relative movement speed between the actuators 03 does not depend on the response frequency of the Z servo circuit 506, the actuator can be moved at a speed close to the response frequency of the actuator, and the recording can be speeded up. Further, by using the FILO type memory mechanism, the distance between the probe electrode and the recording medium may be changed in the order of data read from the storage mechanism, and the apparatus configuration can be simplified.

In the recording method according to the present invention, the probe electrode 501 is connected to the recording medium 50 as shown in this embodiment.
The probe electrode is not limited to two-dimensionally and XY raster-scanned on the probe electrode 3, but is moved, for example, circumferentially or spirally.
1 and the recording medium 503 in the horizontal and vertical relative positions
After temporarily storing data in an O or FIFO (First In First Out) type memory, the height servo may be turned off, and the probe electrode may be relatively moved on the recording medium using the memory information to perform recording. Also in this case, the distance between the probe electrode and the recording medium may be changed in the order of the data read from the storage mechanism, and the apparatus configuration can be simplified.

FIG. 7 is a block diagram showing the configuration of the fourth embodiment of the present invention.

This embodiment has substantially the same configuration as the third embodiment shown in FIG. 5, but performs bit recording by deforming the surface of the recording medium with a probe electrode during recording.

Reference numeral 703 denotes a recording medium on which a probe electrode 701 facing the recording medium is provided in close proximity. The probe electrode 701 includes a cylindrical piezoelectric element 702, which is a Z fine movement mechanism similar to the cylindrical piezoelectric element 502 in the third embodiment (see FIG. 5), and a probe electrode 701.
2 is attached to a Z coarse movement mechanism such as a stepping motor (not shown) for approaching the motor 2.

Normally, the probe electrode 701 and the recording medium 70
3, a bias voltage from the bias circuit 704 is applied, and the bias voltage is brought close to the extent that a tunnel current or a field emission current flows between the probe electrode 701 and the recording medium 703. The tunnel current or the field emission current is converted into a voltage by the current-voltage conversion circuit 705 and then input to the Z servo circuit 706. The Z servo circuit 706 outputs a distance control signal S73 for keeping the tunnel current or the field emission current constant. This distance control signal S73 is applied to an electrode 708 which is a drive electrode of the cylindrical piezoelectric element 702.

Recording in this embodiment is performed as follows.

As described above, the bias voltage from the bias circuit 704 is applied between the probe electrode 701 and the recording medium 703, and the probe electrode 701 and the recording medium 703 are brought close to the extent that a tunnel current flows. When performing recording, the control circuit 710 moves the probe electrode 701 to a desired recording position on the recording medium 703. After the movement is completed, the horizontal position of the probe electrode 701 is fixed, the SW circuit 709 is switched to the B side, and
The Z drive circuit 714 connects the probe electrode 701 to the recording medium 70.
A signal that approaches 3 is generated and applied to the electrode 708.
As a result, the probe electrode 701 pierces the recording medium 703 and performs recording by deforming the surface of the recording medium 703 into a concave shape.

In this embodiment, the probe electrode 701 is made of TiC, which is a hard material having conductivity, and is used after being subjected to electrolytic polishing. Further, as the recording medium 703, Au epitaxially grown on mica was used. This recording medium 703
The probe electrode 701 is pierced on the top and the size is 10 nm.
Fine bits having a diameter of 0.5 nm and a depth of 0.5 nm were formed and used as recording bits. The concave bit at this time is associated with “1” to distinguish it from “0” in the flat portion of the recording medium. The recorded data is encoded by the encoder 71.
In step 5, coding is performed on the data "0" and "1", and binary recording is performed. At this time, the probe electrode 701 is
The recording is performed while the XY raster scanning is performed two-dimensionally on the image 03.

At the time of this recording, the third data shown in FIG.
In the same manner as in the embodiment, during the forward scan of X (+ X direction), the horizontal and vertical relative positions of the probe electrode 701 and the recording medium 703 at the time of piercing are temporarily stored, and at the time of the backward scan (−X direction), After the height servo was turned off and the probe electrode 701 was moved relative to the recording medium 703, the probe electrode 701 was pierced to record a concave bit corresponding to "1".

This specific recording method will be described with reference to FIG.

In this embodiment, at the time of forward scanning (+ X direction), the SW circuit 709 is switched to the A side, and scanning of one raster (n-th raster) is performed while controlling the height in the Z direction. At this time, when the probe electrode 701 approaches the bit recording position corresponding to “1” on the recording medium 703, the control circuit 710 transmits the X-direction scanning signal of the XY fine movement driving circuit 711 by the control signals S71 and S74 to the FILO memory 712.
Then, the distance control signal S73 is stored in the FILO memory 713. By repeating this operation during forward scanning (+ X direction), X-direction scanning signals and distance control signals S73 for the number of bits corresponding to "1" in one raster are stored in each FILO memory 712, 713, respectively. Is done.

At the time of the backward scanning (-X direction) in which the scanning direction of the probe electrode is reversed, the SW circuit 709 is switched to the B side.
The concave bits are recorded on the recording medium 703. At this time, the servo operation for controlling the height of the probe electrode 701 is not performed, and the probe electrode 701 is moved to the recording position on the recording medium 703 in an open loop according to the data stored in the two FILO memories 712 and 713. It is.

The control circuit 711 controls the XY fine movement drive circuit 710 based on the value of the FILO memory 712, and moves the probe electrode 701 in the horizontal direction. At this time, the Z drive electrode 7
08 is supplied with the output of the Z drive circuit 714 via the SW circuit 709.

When the probe electrode 701 moves in the horizontal direction, the control circuit 710 sends the Z drive circuit 714 the probe electrode 7.
01 is sufficiently separated from the recording medium 703 by a voltage value Zin.
It outputs it, and moves in the horizontal direction with the probe electrode 701 separated. After the horizontal movement is completed, the control circuit 7
Numeral 10 adds a recording voltage value (ΔZ) to the value of the FILO memory 713 for recording and outputs the value to the Z drive circuit 714.

The above ΔZ is calculated as follows.
For example, the voltage-displacement characteristic of the cylindrical piezoelectric element 702 as the Z control mechanism is 0.5 nm / V, and the Z servo circuit 70
If the distance between the probe electrode and the sample is estimated to be 1 nm when the distance control is performed in step 6, a voltage of 3 V is applied to the FILO memory 7 to form a concave bit having a depth of 0.5 nm.
13 and is given. Thereby, the recording medium 7
02, a concave bit recording corresponding to "1" is performed. When one bit recording is completed, the Z drive circuit 714 outputs Zinit again to connect the probe electrode 701 to the recording medium 703.
Then, the probe electrode 701 is moved to a bit recording position stored at the next address of the FILO memory 712 to perform recording.

In this way, at the time of the backward scanning (-X direction),
After recording is performed on all bits stored in the value of the FILO memory, the Y-direction scanning signal is changed to move the probe electrode 701 to the next raster (n + 1-th raster). At this time, the SW circuit 709 is switched to the A side again, and the next raster going scanning (+ X direction) is started while controlling the distance between the probe electrode 701 and the recording medium 703 by the Z servo circuit 706.

In this embodiment, a recording apparatus in which a probe electrode is pierced into a recording medium by using STM is described. However, the concept of the present invention is not limited to this. The present invention can also be applied to a recording device that records irregularities or changes in electronic state on the order of nm using electrodes.

[0106]

Since the present invention is configured as described above, it has the following effects.

In the method according to the first aspect, since the recording is performed without performing the feedback control on the distance between the probe electrode and the recording medium, the transfer rate of the recording data can be increased, and the large capacity can be achieved. There is an effect that the information can be promptly processed.

In the method according to the second aspect, in addition to the above-mentioned effects, there is an effect that the distance between the probe electrode and the recording medium at the time of recording can be set to an optimum value.

According to the third and fourth aspects, there is an effect that an information processing apparatus having each of the above effects can be realized.

According to the fifth and sixth aspects of the invention, the information processing apparatus for reciprocally scanning the probe electrode and the information processing apparatus for scanning the probe electrode in the same direction can be simplified. There is.

[Brief description of the drawings]

FIG. 1 is a block diagram showing the configuration of an embodiment of the present invention.

FIGS. 2A and 2B are diagrams showing a recording method of the present invention, wherein FIG. 2A shows a forward scan, and FIG. 2B shows a backward scan.

FIG. 3 is a block diagram showing a configuration of a second exemplary embodiment of the present invention.

FIG. 4 is a diagram showing a triangular pulse voltage used for recording in the embodiment shown in FIG.

FIG. 5 is a block diagram showing a configuration of a third exemplary embodiment of the present invention.

FIG. 6 is a diagram illustrating the operation of each unit in FIG. 5;

FIG. 7 is a block diagram showing a configuration of a fourth embodiment of the present invention.

[Explanation of symbols]

 101, 501, 701 Probe electrode 102 XY stage 103 Probe current amplifier 104 Z-direction drive circuit 106 Power supply 107 XY scan circuit 108 XY-direction fine movement control circuit 109 Coarse movement mechanism 110 Coarse movement drive circuit 111 Microcomputer 112 Display element 113 Surface unevenness storage Device 114 Concavo-convex response drive mechanism 121 Substrate 122 Substrate electrode 123 Recording layer 124 Recording bit 315 Offset adder 502,702 Cylindrical piezoelectric element 503,703 Recording medium 504,704 Bias circuit 505,705 Current-voltage conversion circuit 506,706 Z servo Mechanism 509, 709 SW circuit 510, 710 Control circuit 511, 711 XY fine movement drive circuit 512, 513, 712, 713 FILO memory 514, 714 Z drive circuit S1, S4, S7 , S74 control signal S2, S72 switching signals S3, S73 distance control signal

Continued on the front page (72) Inventor Takahiro Oguchi 3-30-2 Shimomaruko, Ota-ku, Tokyo Inside Canon Inc. (72) Inventor Kunihiro Sakai 3-30-2 Shimomaruko, Ota-ku, Tokyo Inside Canon Inc. (72) Inventor Akihiko Yamano 3-30-2 Shimomaruko, Ota-ku, Tokyo Inside Canon Inc. (72) Inventor Shunichi Shito 3-30-2 Shimomaruko 3-chome, Ota-ku, Tokyo Inside Canon Inc. (72) Invention Person Katsunori Hatanaka 3-30-2 Shimomaruko, Ota-ku, Tokyo Examiner at Canon Inc. Kohei Hirooka (56) References JP-A-4-242061 (JP, A) JP-A-4-241238 (JP, A) (58) Field surveyed (Int. Cl. ⁷ , DB name) G11B 9/14

Claims (5)

(57) [Claims] 1. A probe arranged to face a recording medium.
An electrode scans the recording medium, and the probe electrode is written.
Apply a modulated voltage to the recording medium according to the information
The information is recorded in the same area of the recording medium by the probe electrode .
Scan backward , detect irregularities on the recording medium surface during forward scan ,
The detected unevenness information is stored, and the above described
While changing the distance between the probe electrode and the recording medium in accordance with the stored irregularity information, the information is read by the probe electrode.
Recording method and recording. 2. An offset is added to the stored unevenness information.
In addition, this offset occurs when the probe electrode
The recording method according to claim 1 , wherein the distance between the probe electrode and the recording medium is changed according to the unevenness information to which the information is added . 3. A probe arranged to face a recording medium.
An electrode and a probe for scanning the recording medium with the probe electrode.
Inspection means and a surface of a recording medium scanned by the probe electrode
Unevenness detecting means for detecting the unevenness of the surface, and detecting by the unevenness detecting means.
Between the probe electrode and the recording medium in accordance with the
A concavo-convex response drive mechanism for changing the distance;
A voltage modulated according to the information is applied between the pole and the recording medium.
The information processing apparatus having a power source for recording information by pressing, has a storage device for storing the irregularity information, the scanning means
The probe electrode travels through the same area of the recording medium.
Rescanning, irregularities detected by the detection means during forward scanning
Information is stored in the memory, and is stored in the memory when returning
Read out the unevenness information, and
Accordingly, the probe electrode and the recording medium
While changing the distance, information is collected by the probe electrode.
An information processing apparatus characterized by recording . 4. The unevenness read from the storage device.
With an offset adder that adds an offset to the information
The unevenness drive mechanism is the unevenness information with this offset added.
The distance between the probe electrode and the recording medium according to the
The information processing device according to claim 3 . Wherein said storage device is a FILO type memory mechanism
The information processing device according to claim 3 or 4, wherein