JPH11353721A - Information processor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To perform accurate tracking control for positional correction in raster scanning with a simple mechanism by forming a linear marker in a recording area, detecting the deviating quantity of timing when a probe passes through the marker, and correcting positional deviation between an actual scanning position and a raster position based on the detected deviating quantity. SOLUTION: A maker is provided in the recording area of a medium. One marker (marker I) is formed in the left end in an X scanning direction (main scan) and another marker (marker II) is formed on the diagonal line of a scanning area, the formation of them is carried out by cutting work. When a probe is scanned, a large current flows at the time of its passing through the marker. A time taken from the detection of the marker I to the detection of the marker II is decided by the position of a raster in a sub-scanning direction, and a current scanning position is monitored. Thus, position aligning, i.e. tracking, in the sub-scanning direction is performed by using a time between the marks with respect to each raster.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to an information processing apparatus for performing high-density recording / reproduction using the principle of STM.

[0002]

2. Description of the Related Art In recent years, applications of memory materials have been at the core of the electronics industry such as computers and related equipment, video disks, digital audio disks, and the like, and the development of materials has been very active. Until now, magnetic memories and semiconductor memories using magnetic materials and semiconductors as the main material were mainly used, but with the advancement of laser technology, inexpensive and high-density recording media using optical memories using organic thin films such as organic dyes and photopolymers Has also appeared. In recent years, a scanning probe microscope (hereinafter, referred to as an SPM) capable of directly observing an electronic structure on a material surface and in the vicinity of the surface by using a physical phenomenon (tunnel phenomenon, interatomic force, and the like) generated by bringing a probe and a sample closer to each other. Is abbreviated as a single crystal,
Real space images of various physical quantities can be measured with high resolution regardless of the amorphous state. In the industrial field, attention has been paid to the principle of the high resolution of the atomic or molecular size of SPM, and as described in JP-A-63-161552 and JP-A-63-161553, Application and practical application to information recording / reproducing devices by using layers have been energetically advanced.

[0003]

By the way, in the information recording / reproducing apparatus as described above, the bit size is one.
The bit access at the time of reproduction must be performed with an accuracy on the order of nm. A commonly used actuator for positioning is a piezoelectric element (cylindrical type, laminated type) or the like, and has sufficient positioning accuracy as an actuator. However, since these actuators are displaced due to drift or creep caused by temperature change, it is difficult to correctly access the bit string recorded again only by setting the drive signal to the actuator. for that reason,
At the time of reproduction, it is necessary to correct the above-mentioned positional deviation by some kind of feedback control.

SUMMARY OF THE INVENTION It is an object of the present invention to solve the above-mentioned problems and to provide an information processing apparatus in which tracking control for position correction in raster scanning can be accurately performed by a simple mechanism. is there.

[0005]

According to the present invention, in order to achieve the above object, an information processing apparatus is configured as follows. That is, the information processing apparatus of the present invention is an information processing apparatus that performs parallel scanning of a probe on a recording medium surface by raster scanning, and writes and reads information by physical interaction between the probe and the recording medium. And the amount of deviation of the timing at which the probe passes through the recording medium on which a linear marker is formed in the recording area, and the positional deviation between the actual scanning position and the raster position is detected based on the detected amount of deviation. And tracking control means for correcting Also,
The information processing apparatus according to the present invention is characterized in that the linear markers are formed diagonally with respect to a recording area. Further, the information processing apparatus according to the present invention is characterized in that the linear marker is formed by cutting with the probe. Further, the information processing device of the present invention
The information based on the physical interaction between the probe and the recording medium is a current value. Further, the information processing apparatus according to the present invention is characterized in that the deviation amount is detected by calculating a time when the probe passes through the marker. Further, the information processing apparatus according to the present invention is characterized in that the deviation amount is detected by recording a time when the probe passes through the marker. Further, the information processing device of the present invention, the detection of the shift amount by recording the time, the marker detection timing detected by the probe at the time of recording, the marker detection timing detected by the probe at the time of reproduction, It is characterized in that comparison is performed at the time of reproduction.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS According to the present invention, a deviation of a detection timing is obtained from a linear marker formed in a recording area of a recording medium, and tracking control is performed based on the deviation of the detection timing. Accordingly, tracking control for position correction in raster scanning can be accurately performed by a simple mechanism.

[0007]

Embodiments of the present invention will be described below. [First Embodiment] FIG. 1 schematically shows a system configuration of an information processing apparatus according to a first embodiment of the present invention. Reference numeral 101 denotes a cantilever-shaped lever, and a probe 102 is provided at the tip thereof. In this embodiment, since the current is used as a physical phenomenon to be detected by approaching the probe, the recording medium 103 and the probe 102 are formed of Au which is a conductive material. After the current detected by the probe 102 is converted into a voltage signal by the IV conversion unit 106, the control unit 10
8 is input. Although not shown, a part of the voltage signal input to the control unit 108 is sent to a subsequent data processing circuit as reproduction data to reproduce information. The other part is sent to an approach control unit 111 for controlling the distance between the probe 102 and the medium 103 based on the magnitude of the current value, and is used as a feedback detection signal.

On the other hand, a recording medium 103 has a stage 104 provided with an actuator for scanning in parallel with the medium surface.
It is installed in. Although the actuator is not shown, an XY stage using a laminated piezoelectric element is used in the present embodiment. The scanning control unit 107 generates a rotation driving signal of the stage according to a control signal from the control unit 108. After the drive signal is amplified through the amplifier circuit 105, it is applied to the actuator of the stage 104. Specifically, a triangular wave is applied with the X direction as the main scanning direction, and a small moving amount determined in the Y direction as the sub scanning direction is applied in a stepwise manner. The Y direction is used for raster access. The recording / playback bias control unit 110
For applying a pulse voltage for recording and a DC voltage for reproduction.

The probe consisting of 102 and 103 in FIG. 1 has a structure as shown in FIG. 2, for example, and is manufactured by using a silicon single crystal as a material by a semiconductor process. Reference numeral 201 denotes a conductive probe made of Au as described above. Reference numeral 203 denotes a wiring pattern for electrically connecting the probe 202, which is also formed by Au patterning. Next, the tracking control unit 10
9 will be described. The tracking control unit 109 has I-
A mechanism that detects a position of a marker on a medium described later with reference to a signal of the V conversion unit 106, compares the detected position with a target position, and performs tracking control through the scanning control unit 107. Internally, it mainly comprises arithmetic processing means, storage means, time measuring means and the like.

Next, a medium which is a characteristic part of the present invention will be described. The medium is shown in FIG.
It is set on the stage 104 and scanned in a two-dimensional direction relative to the probe and parallel to the medium surface. The recording medium is disclosed in JP-A-63-161552 and JP-A-63-1.
No. 61553 is used. LB of π-electron conjugated polyimide
This is an LB film (organic monolayer film) in which six layers are accumulated on an Au plate electrode by the (Langmuir-Blodgett) method.
The recording medium 103 in FIG. 1 is formed on a substrate. The substrate electrode used was Au epitaxially grown on a smooth silicon substrate. Recording was performed by sequentially applying a pulse voltage to the current detection probe in time series as described above, and the applied pulse waveform was a triangular wave having a peak value of 3V.
The reproduction was performed by applying a DC bias of 2 V to the substrate side and measuring the current. The pit diameter by this method was 10 nm.

The feature of the present invention is as shown in FIG.
This means that a marker is provided in the recording area. Marker
Indicates one line (marker I) at the left end in the main scanning (X scanning) direction.
One (marker II) is formed on the diagonal of the inspection area,
The width of the marker is 10 to several tens nm. this
Is formed by cutting with a probe in this embodiment, for example.
Done. The contact pressure of the probe to the medium during conventional recording and reproduction
Is 10^-7N or less, while the pressing pressure of the probe is 1
0^-6Cutting the LB film as a recording medium by raising it to about N
It was done. In this embodiment, the cutting process is performed in this manner.
Processing, but processing the pattern by process, etc.
It is also possible. The LB film has a thickness of about 3 nm.
Very high resistance despite recording
In the unexposed area, it usually has a resistance of several hundred M to several GΩ.
I was On the other hand, by processing the marker,
When the probe is scanned as shown in the right figure of Fig. 3
FIG. 4 shows a detection signal (in the case of this embodiment,
Is a current signal). Marker for base current
Time passed (T ₀Large current is flowing in
You.

[0012] Next is moved a small amount in the Y-direction marker position as the lower waveform of Figure 4 is shifted to T _1. Where T ₀ , T
₁ indicates the time from the detection of the marker I to the detection of the marker II. Each time is determined by the position of the raster in the sub-scanning direction, and the current scanning position can be monitored. For example, when the time between markers in raster i is T, raster i + 1 is T + ΔT,
Since the marker II is drawn diagonally, ΔT is a fixed increment. Therefore, since the time between markers is determined for each raster, the position in the sub-scanning direction (hereinafter referred to as tracking) can be performed using the value. For example, if the AB raster shown in FIG. 3 is the i-th raster, T _i = i × ΔT,
If the value is larger than the value at the time of actual scanning, it indicates that the scanning position is shifted below the raster position.
On the other hand, when the value is smaller than the value, it can be seen that it is shifted upward. This makes it possible to implement tracking by applying feedback.

The above system was actually used for recording and reproduction.
The scanning area was X: 100 μm, Y: 100 μm, and the raster interval was 50 nm. When the scanning speed was 2 mm / sec, ΔT at this time was 25 μsec. In this case, if the 1-nm scanning position deviates from the raster, T
Will change. When the scanning position control was performed by performing feedback control based on this value, the raster was lost during scanning in the conventional setting of the scanning position only by setting the driving signal. Raster can now be played. When the error rate was set, the result was improved by two digits or more.

In this embodiment, the case where the marker I exists is described. However, even when the marker I does not exist, if the position of the reference raster is determined, the marker II is calculated from the position.
Since the detection timing can be predicted, the same tracking control as described above was possible. The arithmetic mechanism and the storage mechanism for the tracking are shown in FIG.
Is controlled by the tracking control unit 109.

Second Embodiment FIG. 5 shows a second embodiment of the present invention. In the first embodiment, the target value of the probe transit time T between the markers is determined by calculation, but in the present embodiment, the value of T at the time of actual recording is directly written in the data area, thereby controlling the position during reproduction. Used for The one shown in FIG. 5 corresponds to, for example, the raster of the portion AB shown in FIG. The black part indicates the time of marker detection, and in FIG. 5, it is the time of starting scanning (marker I) and the middle of scanning (marker II).
It appears as. Other “0” and “1” are recorded information data. The shaded area at the end of scanning is used to record the value of T in the raster. Actually, the number of clocks in units of 1 μsec was recorded. This clock is provided in the tracking control unit 109 shown in FIG.

First, a case where information data is recorded as a recording / reproducing procedure will be described. When the marker I is detected, a detection signal is sent from the IV conversion unit 106 of FIG. 1 to the tracking control unit 109, and a timer starts. Next, the probe records information by the same method as that shown in the first embodiment. Stopping the timer when it detects the marker II, stores time T ₀ at that time 109 in the internal memory of the. Next, the remaining information is written again, and the transit time (T ₀ ) between the markers stored in the internal memory is recorded in the last part of the raster. Then, a raster having a structure as shown in FIG. 5 is created.

Next, at the time of reproduction, first, the marker I is detected,
Start the timer. Read information, then marker II
Is detected, the timer is stopped, and the value (T ₀ ′) is stored. The information reading is continued again, and finally, the recorded inter-marker probe passage time (T ₀ ) is read. Then, the stored T ₀ ′ is compared with T ₀ read from the data, and the error amount is used for position correction. For example, if the time at the time of reproduction is longer than the time at the time of recording (T ₀ <T ₀ ′), the reproduction scan is shifted below the raster (shown in FIG. 3), and if it is smaller (T ₀ >). T ₀ ′) indicates that it is shifted upward.

The feedback method was performed using conventional PID control. As a result, as in the first embodiment, in the conventional setting of the scanning position using only the driving signal, the raster was lost during scanning, but all rasters can be reproduced by applying the present invention. . When the error rate was set, the result was improved by two digits or more.

[0019]

As described above, according to the present invention,
In recording and reproduction in raster scanning, a deviation amount is detected by a linear marker formed in a recording area of a recording medium, and a deviation between an actual scanning position and a raster position is corrected based on the detected deviation amount. Thus, accurate position correction can be performed. Further, in the present invention, since the marker can be formed with the same probe and the same system as the recording / reproducing probe, the above-described position correction can be realized with a simple configuration.

[Brief description of the drawings]

FIG. 1 is a schematic diagram of a system configuration according to a first embodiment.

FIG. 2 shows the shape and structure of a probe according to the first embodiment.

FIG. 3 is a diagram illustrating a configuration of a medium and a shape of a marker.

FIG. 4 is a detection waveform of a marker.

FIG. 5 is a diagram illustrating a data format in a raster according to a second embodiment.

[Explanation of symbols]

 101: lever 102: probe 103: recording medium 104: stage 105: amplifier circuit 106: IV converter 107: scanning controller 108: controller 109: tracking controller 110: recording / playback bias controller 111: approach Control unit 201: probe 202: probe 203: wiring pattern

Claims (7)

[Claims] An information processing apparatus for performing parallel scanning of a probe on a recording medium surface by raster scanning and writing and reading information by physical interaction between the probe and the recording medium. Tracking control for detecting a shift amount of a timing at which the probe passes through the recording medium on which the marker is formed, and correcting a position shift between an actual scanning position and a raster position based on the detected shift amount. An information processing apparatus comprising: means. 2. The information processing apparatus according to claim 1, wherein the linear markers are formed diagonally with respect to a recording area. 3. The information processing apparatus according to claim 1, wherein the linear marker is formed by cutting with the probe. 4. The information processing apparatus according to claim 1, wherein the information based on the physical interaction between the probe and the recording medium is a current value. . 5. The information according to claim 1, wherein the detection of the shift amount is performed by calculating a time when the probe passes through the marker. Processing equipment. 6. The information according to claim 1, wherein the detection of the shift amount is performed by recording a time when the probe passes through the marker. Processing equipment. 7. A method of detecting a shift amount by recording the time, comprising comparing a marker detection timing detected by the probe during recording with a marker detection timing detected by the probe during reproduction during reproduction. The information processing apparatus according to claim 6, wherein the information processing is performed by: