JP3042817B2 - Apparatus and method for relative positioning in information recording / reproducing 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 recording / reproducing apparatus for recording / reproducing information by using a probe which is close to a recording medium by a distance of about 1 nm by applying the principle of a scanning probe microscope. The present invention relates to a relative positioning device for a recording medium and a probe.

[0002]

2. Description of the Related Art In recent years, a scanning tunneling microscope (hereinafter referred to as STM) capable of observing the surface of a conductive material with a resolution of nanometers or less has been developed as described in US Pat. No. 4,343,993. Atomic and molecular scale observations have been made on the atomic arrangement of metal and semiconductor surfaces, the orientation of organic molecules, and the like. In addition, with the development of STM technology, an atomic force microscope (hereinafter, referred to as AFM) and a near-field optical microscope (hereinafter, referred to as NFOM) capable of observing the surface of an insulating material or the like with the same resolution as STM have also been developed. (US Pat. No. 4,724,318, European Patent Application-0)
112401). Therefore, this STM, A
Scanning probe microscopes such as FM and NFOM (hereinafter SPM
(U.S. Pat. No. 4,575,822) has been proposed in which a probe is accessed on an atomic or molecular scale with respect to a recording medium and recording and reproduction are performed, thereby realizing a high-density memory. And JP-A-63-161552 and 161553.

Further, an apparatus for forming a plurality of probes on a semiconductor substrate for the purpose of miniaturization and displacing and recording a recording medium facing the probe is disclosed in European Patent Application Publication No. 024721.
No. 9 discloses this. In these, a plurality of cantilevers formed by a semiconductor process are provided with a probe for detecting a tunnel current, and a recording medium opposed thereto is attached to a cylindrical piezoelectric element, and recording and reproduction are performed by performing a circular motion. It is carried out.

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. Usually, the distance between these two substrates is set to 1 to 3 μm. Further, the variation amount of the distance is required to be ± 0.5 μm or less. Therefore, a plurality of plate electrodes for detecting capacitance are provided on the probe head substrate and the recording medium substrate, and the capacitance between them is detected.
Japanese Patent Application No. 4-84750 discloses a device for adjusting the interval and the inclination between the two substrates so that they are equal to each other at a certain value.

Further, when recording and reproduction are performed by scanning the surface of the recording medium using the probe head, the probe head and the recording medium must be aligned in the in-plane direction of the recording medium. Therefore, in the same manner as described above, a plate electrode for detecting capacitance is provided on the probe head substrate and the recording medium substrate, the capacitance is detected, and the value of the capacitance is maximized. Japanese Patent Application No. 3-293908 discloses a device for adjusting the relative position of the two substrates in the in-plane direction so that the overlapping area of the electrodes is maximized.

[0006]

However, in the prior art apparatus for adjusting the relative position of the probe head substrate and the recording medium substrate in the in-plane direction, the rotation center of the probe head substrate and the recording medium are moved by the in-plane movement. Since the two are driven to rotate relative to each other after the center of rotation of the substrate is aligned, there are the following problems. Even if the center of rotation of the probe head substrate and the center of rotation of the recording medium substrate are aligned, there is a slight in-plane misalignment between both centers of rotation and the center of rotation of the actual relative rotation drive mechanism. During actual relative rotation driving, an in-plane positional shift may occur between the rotation center of the probe head substrate and the rotation center of the recording medium substrate. For this reason, the accuracy of the relative position adjustment with respect to the rotation is reduced, and this may further lead to a reduction in the accuracy of the relative position adjustment in the in-plane direction.

[0007]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention provides an apparatus for relative positioning between a multi-probe substrate and a recording medium substrate. The upper and lower plate electrode pairs are arranged to face each other in each of the y, z and θ directions around the Z axis, and the capacitance formed between the upper and lower plate electrodes in each direction is detected. It is characterized in that the driving means for each direction is controlled based on each detection result.

In the present invention, each of the upper and lower plate electrodes is formed in a shape for coarse adjustment and fine adjustment, and the alignment is performed by two-stage adjustment of coarse adjustment and fine adjustment.

Further, according to the present invention, the detection result in the x and y directions is represented by z
By dividing by the direction detection result, the displacement in the z direction due to the relative movement in the x and y directions is compensated.

Further, according to the present invention, the multi-probe substrate and the recording medium substrate are minutely vibrated in the x and y directions to synchronously detect a periodic change in capacitance, thereby improving detection accuracy.

Further, according to the present invention, one of the upper and lower plate electrodes is divided into two, and the difference between the two generated capacitances is obtained, thereby constituting a differential detecting means.

[0012]

The magnitude of the capacitance generated between the upper and lower plate electrodes provided to face the multi-probe substrate and the recording medium substrate which relatively move in the in-plane direction is the magnitude of the distance in the z direction. It is proportional to the size of the opposing areas of the upper and lower plate electrodes. From this, the amount of movement in each direction can be detected by detecting the capacitance between the electrodes provided corresponding to the respective directions of x, y, z and θ.

A minute displacement can be detected by using a comb-shaped electrode, and a differential displacement can also be detected by using a two-divided electrode.

[0014]

FIG. 1 shows an embodiment relating to a position control electrode in a positioning apparatus according to the present invention. Recording medium chip 1
A plurality of probes 103 that perform high-density recording and reproduction opposing the recording medium 102 on the multi-probe chip 104 are provided on the multi-probe chip 104. Multi probe tip 10
4, four z-direction position control upper electrodes 105, 106, 107, and 108 in the figure, an x-direction position coarse adjustment control upper electrode 109, an x-direction position fine adjustment control upper electrode 110, around the probe, Upper electrode 11 for y-direction position coarse control
1. An upper electrode 112 for y-direction position fine adjustment control, an upper electrode 113 for θ-direction position coarse adjustment control, and an upper electrode 114 for θ-direction position fine adjustment control are provided. On the recording medium chip 101, around the recording medium 102, z-direction position control lower electrodes 115, 116, 117, 118, x-direction position coarse adjustment control lower electrode 119, and x-direction position fine adjustment control lower electrode 120. , Y-direction position coarse control lower electrode 121, y-direction position fine control lower electrode 122, θ-direction position coarse control lower electrode 123, θ-direction position fine control lower electrode 124
Is provided. Also, the multi-probe tip 104
An oscillating circuit 125 is integrated on the top, and an oscillating signal is
It is supplied to each of the electrodes 105 to 114 on the multi-probe chip 104 through wiring (not shown in FIG. 1) on the multi-probe chip 104. Multi probe tip 1
The above oscillation signals are respectively applied to the electrodes 115 to 124 on the recording medium chip 101 at positions opposite to the electrodes 105 to 114 on the multi-probe chip 104 by capacitive coupling between the electrodes on the multi-probe chip 104. Is transmitted. On the recording medium chip 101, a capacitance detection circuit 126 is integrated. The oscillation signal transmitted to each of the electrodes 115 to 124 is individually transmitted through a wiring (not shown in FIG. 1) on the recording medium chip 101 to the capacitance detection circuit 126.
And the recording medium chip 1 corresponding to each electrode on the multi-probe chip 104 is detected from the magnitude of the oscillation signal.
Detection of the magnitude of the capacitive coupling between each electrode on 01, that is, the capacitance is performed.

In order for the plurality of probes 103 to perform high-density and high-reliability recording / reproduction on the recording medium 102, the relative position between the two must be controlled with an accuracy of 1 μm or less. In consideration of the length of the probe provided in the recording medium, the relative position control between the recording medium chip 101 and the multi-probe chip 104 requires an accuracy of ± 0 within the range of 5 to 30 μm in the z direction in FIG. .1 μm,
In the drawing, it is required that the positioning control in the x and y directions achieves a level of accuracy of ± 0.1 μm in a range of ± 1000 μm.

First, as a method of controlling the interval and tilt in the z direction, upper electrodes 105, 106, 107 and 108 for controlling the z direction on the multi-probe chip 104 and the corresponding z direction on the recording medium chip 101 are controlled. The capacitances between the lower electrodes 115, 116, 117 and 118 for position control are individually detected. Since the capacitance between the electrodes is inversely proportional to the electrode spacing, by detecting these capacitances, the capacitance between the upper and lower electrodes 105-115, 106-
The intervals between 116, 107-117, and 108-118 can be obtained. For example, if the size of the upper electrode is 5
00 μm × 500 μm, size of lower electrode is 2500 μ
m × 2500 μm (the reason why the size of the upper electrode and the size of the lower electrode do not match will be described later), and when the distance between the electrodes is 10 μm, the magnitude of the capacitance between the electrodes becomes
225 fF. Conversely, the electrode interval is set to 10 μm
In order to control this with an accuracy of ± 0.1 μm, a capacitance of 225 fF is detected with an accuracy of ± 2.5 fF, and the recording medium chip 10 is controlled so that the capacitance is constant.
It can be seen that the distance between 1 and the multi-probe tip 104 may be controlled by a driving element such as a piezo element. In addition, four z-direction position control upper and lower electrodes 105-115
, 106-116, 107-117, 108-1
Compare the capacitances between 18 and make them equal,
By controlling the inclination of the interval between the recording medium chip 101 and the multi-probe chip 104 by a driving element such as a piezo element, the inclination can also be corrected.

The method for controlling the alignment in the x and y directions will be mainly described in the x direction. Recording medium chip 10
1 and the multi-probe tip 104 are aligned in the x direction, the upper electrode 109 for coarse adjustment in the x direction and the x
Capacitance (hereinafter referred to as a coarse x signal) between the lower electrode 119 for directional position coarse adjustment control and ± 10%
Rough positioning with an accuracy of about μm is performed, and then the capacitance between the upper electrode 110 for x-direction position fine adjustment control and the lower electrode 120 for x-direction position fine adjustment control (hereinafter, referred to as a fine x signal) is determined. Upon detection, fine positioning with an accuracy of ± 0.1 μm is performed. Since the degree of overlap between the upper and lower electrodes can be detected from the magnitudes of the coarse x signal and the fine x signal, the recording medium chip 101 and the multi-probe chip 104
When the relative movement in the direction and the magnitude of the capacitance become the maximum, it may be determined that the overlap of the upper and lower electrodes is the maximum, that is, that the alignment has been performed. Similarly, the positioning in the y direction is performed. The alignment does not necessarily have to be performed when the magnitude of the capacitance reaches the maximum value, and may be performed when the capacitance reaches a predetermined value. However, for convenience, the case of the maximum value will be described below.

Next, FIG. 2 shows how the upper and lower electrodes forming the capacitance overlap. 2A shows the positional relationship between the upper and lower electrodes in the alignment completed state, FIG. 2B shows the positional relationship in a state where a positional shift has occurred in the x direction, and FIG. 2C shows the positional relationship in the x and y directions. The positional relationship of the states that have occurred is shown below.

In FIG. 2, what is shown in black is
Upper electrodes 105 and 10 on multi-probe tip 104
6, 109 and 110, the corresponding lower electrodes 11 on the recording medium chip 101 are indicated by hatching.
5, 116, 119 and 120 are shown. The shape of the upper and lower electrodes 109 and 119 for coarse adjustment control is a rectangle having a short side in the alignment direction (x direction in FIG. 2). This is to improve the accuracy of positioning by shortening the shape in the positioning direction, and to increase the electrode area by increasing the length in the direction orthogonal to the positioning direction (y direction in FIG. 2). This is to increase the absolute value of the capacitance signal. Upper and lower electrodes 110, 1 for fine adjustment control
The shape of 20 is a comb shape in which a plurality of rectangular electrodes having long sides in the direction orthogonal to the alignment direction (y direction) are arranged at equal intervals in the alignment direction (x direction). This is to further improve the positioning accuracy by shortening the short side of the rectangle and to connect the electrodes electrically to increase the absolute value of the capacitance signal by increasing the electrode area. In addition, by arranging the electrodes at equal intervals, fine positioning at each interval is enabled.

Upper electrodes 105 and 106 for position control in the z direction
The reason why the size of the lower electrodes 115 and 116 for position control in the z direction is larger than that in the above case is that when a positional displacement within a certain amount occurs in the x and y directions, the overlapping area of the upper and lower electrodes decreases,
This is to prevent the capacitance signal from decreasing (see FIG. 2).
(See (b) and (c)). Similarly, the x-direction position coarse / fine adjustment control upper electrodes 109 and 110 are compared with the x-direction position coarse / fine control.
The length of the fine adjustment control lower electrodes 119 and 120 in the direction (y direction) orthogonal to the alignment direction is large.
This is to prevent the overlapping area of the upper and lower electrodes from decreasing when a positional displacement within a certain amount occurs in the direction, thereby preventing the capacitance signal from decreasing. Compared with the upper electrode 110 for x-direction position fine adjustment control, the lower electrode 120 for x-direction position fine adjustment control
The reason why the number of electrodes is large in the alignment direction (x direction) is to increase the fine alignment range (stroke). Here, for example, if the size of the upper electrode for x-direction coarse control is 100 μm × 500 μm, the size of the lower electrode for x-direction coarse control is 100 μm × 2500 μm, and the distance between the upper and lower electrodes is 10 μm, The magnitude of the capacitance (coarse x signal) is 45 fF. Conversely, it can be seen that coarse alignment in the x direction can be performed with an accuracy of ± 1.0 μm by detecting a change in the coarse x signal with an accuracy of ± 4.5 fF. Also, the size of the upper electrode for x-direction position fine adjustment control is 10 μm × 500 μm, and the period in the x direction is 20 μm.
μm, number 25, the size of the lower electrode for fine adjustment control in the x direction is 10 μm × 2500 μm, and the period in the x direction is 20 μm.
m, 125 pieces, and the interval between the upper and lower electrodes is 10 μm.
The magnitude of the capacitance (fine x signal) between the electrodes is 112.5f
It becomes F. Conversely, it can be seen that in order to perform fine positioning in the x direction with an accuracy of ± 0.1 μm, it is sufficient to detect a change in the fine x signal with an accuracy of ± 1 fF.

FIG. 3 shows actual waveforms of the coarse x signal and the fine x signal. Recording medium chip 101 and multi-probe chip 1
04 moves relatively and the coarse x signal goes from the minimum value to the minimum value through the maximum value until the fine x signal reaches the minimum value between the minimum value and the maximum value with the pitch of the electrode arrangement in the x direction as a cycle. One or two times. By converting the maximum value of the coarse x signal into a positional shift amount in the x direction and detecting the same with an accuracy equal to or less than the period of the fine x signal, the maximum value of the coarse x signal among a plurality of maximum values of the fine x signal is supported. A specific maximum can be detected. Further, by accurately detecting the maximum value of the fine x signal, highly accurate alignment of the recording medium chip and the multi-probe chip in the x direction is realized.

Here, in order to improve the detection accuracy of the maximum value of the capacitance signal such as the fine x signal, a synchronous detection method is used. FIG. 4 is a signal waveform diagram in the synchronization detection method. this is,
The recording medium chip 101 and the multi-probe chip 104 are relatively vibrated in the x direction (frequency f), and the fluctuation component of the capacitance signal due to the vibration is synchronously detected by the reference signal of the frequency f. The maximum value (or the minimum value) of the capacitance signal is detected from the zero cross point (= the point where the phase of the fluctuation component of the capacitance signal is inverted with respect to the phase of the reference signal). When this synchronous detection method is used, the detection speed is reduced, but the detection accuracy is usually improved to 1/10 or less as compared with the method of directly detecting the maximum value. Actually, in the case of the above numerical example, a piezo element (FIG. 1)
0), the recording medium chip 101 and the multi-probe chip 104 are driven in the x direction at a frequency f = 10.
When the relative oscillation is performed at 0 Hz and the amplitude is 1 μm, the capacitance signal and the reference signal are input to the lock-in amplifier, and the synchronization detection signal is detected through a low-pass filter having a band of 1 Hz, the zero cross point of the synchronization detection signal is ± 0.1 μm. Detection was possible with the following accuracy. Therefore, the recording medium chip 101 and the multi-probe chip 104 are set to ± 1 in the x direction.
In the range of 000 μm, relative positioning could be performed with an accuracy of ± 0.1 μm every 20 μm. As described above, the alignment in the x direction has been described as an example, but the same applies to the alignment in the y direction.

Now, as described above, the x of the recording medium chip 101 and the multi-probe chip 104
When the relative movement in the (y) direction is performed, a relative movement actually occurs in the z direction due to a driving error or a mounting error of a driving element or a guide, and the distance between the recording medium chip 101 and the multi-probe chip 104 is actually increased. May fluctuate.

FIG. 5 shows a capacitance signal C ₁ (hereinafter referred to as a coarse x (y) signal) between the upper and lower electrodes 109 and 119 for coarse position adjustment in the x (y) direction in such a case. y) Capacitance signal C ₂ (hereinafter referred to as fine x (y) signal) between position upper and lower electrodes 110 and 120 for fine-tuning control, and capacitance signal C ₃ between upper and lower electrodes 106 and 116 for position control in z direction. (Hereinafter z
Signal). Thus, x
If the relative (interval) movement also occurs in the z direction along with the relative movement in the (y) direction, the magnitude of the capacitance in the x and y directions is inversely proportional to the interval in the z direction. A change occurs in the size of the capacitance. This gives an error to the detection of the maximum value of the capacitance signal at the time of the alignment control in the x and y directions, and causes a reduction in the alignment accuracy. Therefore, to avoid this, the coarse x (y) signal and the fine x
(Y) The signal (FIG. 5, waveforms C ₁ and C ₂ ) is converted into a z signal (FIG. 5,
Division by the waveform C ₃ ) and normalization (FIG. 5, waveform C _{1)
/ C 3, C 2 / C} 3). By normalizing in the θ direction in the same manner as in the x (y) direction, capacitance signals in each of the x, y, and θ directions, which are not affected by the interval fluctuation in the z direction, can be obtained. Matching becomes possible.

Next, a description will be given of a positioning control method in the θ direction, which is a rotation about the Z axis. In order to adjust the position in the θ direction, the capacitance between the upper and lower electrodes 109-119 and 110-120 for coarse / fine adjustment in the x direction (coarse x
Signal and fine x signal), and simultaneously, the upper and lower electrodes 113-123 and 114 for coarse / fine adjustment in the θ direction position.
−124 (hereinafter referred to as coarse θ signal and fine θ signal, respectively)
Signal), and calculates the maximum misalignment amount in the x direction of the coarse (fine) x signal and the coarse (fine) θ signal (see FIGS. 6 and 7). The calculated amount of displacement in the x direction is defined as Δx. When the distance between the electrode in the y direction (between the centers of the electrode patterns) between the electrode for coarse adjustment / fine adjustment in the x direction and the electrode for coarse adjustment / fine adjustment in the θ direction is d, the ratio Δx / d becomes Is the amount of rotational position shift as an angle. The rotational position shift is corrected by driving the recording medium chip 101 and the multi-probe chip 104 by a driving element such as a piezo element.
This is done by relative rotation in the direction. Since this rotation center is generally different from the center of the recording medium chip 101 or the multi-probe chip 104, a relative position shift occurs in the x and y directions with the rotation in the θ direction. Therefore, it is necessary to correct the rotational position shift in combination with the correction of the position shift in the x and y directions.

The procedure for positioning will now be described with reference to FIG.
This will be described with reference to FIG. FIG. 10 is a diagram conceptually showing the configuration of the xyθ direction driving mechanism. In the figure, reference numeral 1000 denotes a frame. In the frame, an x-direction fine movement mechanism 1004 for finely moving the recording medium chip 101 in each direction in order to relatively move the recording medium chip 101 and the multi-probe chip 104 facing each other at intervals, a θ-direction fine movement mechanism 1005, a y-direction fine movement mechanism 1006 and a piezo element 1009 as a driving source thereof are provided, and an x-direction coarse movement mechanism 10 for coarsely moving the multi-probe tip 104 in each direction.
01, θ-direction coarse movement mechanism 1002, y-direction coarse movement mechanism 100
3 and a motor 1008 as a driving source for the recording medium chip 101 and the multi-probe chip 1
Piezo element 1007 for adjusting the interval of 04 and its inclination
Is provided.

First, an x-direction coarse movement mechanism 10 composed of, for example, a DC servo motor, a stepping motor, etc.
01 to drive the recording medium chip 101 and the multi-probe chip 104 relative to each other in the x direction.
The maximum value position of each signal is detected, and as shown in FIG. 6, the maximum value position shift amount is calculated. Based on the calculated positional deviation amount, since the distance d is known, the θ-direction coarse coarse positional deviation amount is obtained.
002 is driven to perform coarse correction of the rotational position shift in the θ direction. The x-direction coarse movement mechanism 1001 is driven again, and the driving is stopped at the maximum value position of the coarse x signal. Similarly, y-direction coarse movement mechanism 1
003 is driven, and the driving is stopped at the maximum value position of the coarse y signal. Next, an x-direction fine movement mechanism 1 composed of, for example, a piezo element
004 is driven to relatively vibrate the recording medium chip 101 and the multi-probe chip 104 in the x direction. In this state, the x-direction coarse movement mechanism 1001 is driven to detect zero-cross points corresponding to the alignment positions of the synchronization detection signal of the fine x signal and the synchronization detection signal of the fine θ signal, respectively.
The position deviation amount of the cross point is calculated (the relative vibration in the x direction is stopped). Based on the calculated position shift amount, the θ direction rotation fine position shift amount is obtained, and the θ direction coarse movement mechanism 1002 and the θ direction fine movement mechanism 1005 are driven according to this amount to perform fine correction of the θ direction rotation position shift. . Again, the x-direction fine movement mechanism 10
04 is driven to cause relative vibration in the x direction, and in this state, the x direction coarse movement mechanism 1001 is driven to stop driving at the zero cross point position of the synchronization detection signal of the fine x signal. zero·
For fine positioning in the x direction near the cross point, linear driving (DC driving) may be used in addition to oscillating driving (AC driving) of the x direction fine movement mechanism 1004. After the fine positioning in the x direction is completed, the relative vibration in the x direction stops. Finally, the y-direction fine movement mechanism 1006 is driven to relatively vibrate the recording medium chip 101 and the multi-probe chip 104 in the y direction. In this state, the y-direction coarse movement mechanism 100
3 is driven, and the driving is stopped at the zero-cross point position of the synchronization detection signal of the fine y signal. For fine positioning in the y direction near the zero cross point, linear driving of the y direction fine movement mechanism 1006 may be used as in the x direction. After the fine positioning in the y direction is completed, the relative vibration in the y direction stops. Thus, the coarse / fine adjustment of the three axes in the x, y, and θ directions is completed.

Next, the procedure of the relative movement (x, y directions) between the recording medium chip 101 and the multi-probe chip 104 will be described. First, based on the current alignment position, the x-direction coarse movement mechanism 1001 is driven to relatively move in the x-direction by a desired amount which is a multiple of the x-direction interval of the x-direction fine adjustment control electrode. Driving the moving mechanism 1003,
The relative movement is performed in the y direction by a desired amount which is a multiple of the y direction interval of the y direction fine adjustment control electrode. Next, the x-direction fine movement mechanism 1004 is driven to relatively vibrate the recording medium chip 101 and the multi-probe chip 104 in the x direction. Next, in this state, the x-direction coarse movement mechanism 1001 is driven, and the fine x
Driving is stopped at the position of the zero crossing point near the relative movement position of the signal synchronization detection signal. Thereafter, the relative vibration in the x direction stops. Finally, similarly to the x direction, the y direction fine movement mechanism 1006 is driven in the y direction to perform relative vibration in the y direction. In this state, the y-direction coarse movement mechanism 1003 is driven to
Driving is stopped at the position of the zero crossing point near the relative movement position of the signal synchronization detection signal. Thereafter, the relative vibration in the y direction stops. Thus, the relative movement at predetermined intervals in the x and y directions is completed.

The positioning apparatus as described above
In the figure, the shape of the lower electrode for x, y, θ direction position fine control
The explanation is given by taking a simple comb shape as an example
However, in actuality, as shown in FIG.
The width of a single electrode in the x (y) direction and two adjacent electrodes
The ratio to the gap between the poles is not 1: 1, but 1: 2-3
Set, and two nested electrodes like this were nested
Shall be. FIG. 8 shows two lower electrodes 802 and 80
3, the overlap of the upper electrode 801 became symmetric.
It is in such a state. The upper electrode 801 and the lower electrode 802
Between the upper electrode 801 and the lower electrode 803
Signals simultaneously and independently, and by taking the difference between the two signals
High-accuracy differential alignment is possible. Also, both signals
By comparing the phases of the
It is possible to detect the relative displacement direction of the probe tip.
You. For these, using the actual signal waveform shown in FIG.
explain. Capacitance between upper electrode 801 and lower electrode 802
Quantity signal C_FourBetween the upper electrode 801 and the lower electrode 803
Capacity signal C_FiveIs periodically changed in size as shown in FIG.
Moving component (= original signal component), independent of relative movement
5 shows a waveform to which a certain constant offset component is added. Office
The cause of the cut component is the static electricity between the upper and lower electrodes.
Components of the capacitance signal that are not related to relative movement,
Components due to the capacitance between lines, errors in the capacitance detection circuit
And other components. Using such a capacitance signal
When performing alignment, use the synchronization detection method as described above.
The maximum value may be detected by
It is easier to detect a value between the maximum and minimum values.
The positioning can be performed with a high degree of accuracy. However
The capacitance signal has an offset component as described above.
And larger due to the spacing in the z-direction between the upper and lower electrodes.
Is variable, so detecting an intermediate value will result in
It is difficult to obtain. Therefore, the capacitance signal C_FourAnd capacitance signal
Issue C_FiveDifference signal (C _Four-C_Five) To align
By doing so, the point of zero cross shown in FIG. 9 (for example,
(Point P in FIG. 9).
Gives the accuracy and the offset component is canceled by the difference
Alignment at a point not affected by z-direction interval variation
It became possible. In addition, detection of the relative displacement direction
For example, the capacitance signal C shown in FIG._FourPoint a of the maximum value of
When trying to perform positioning with
Therefore, if it is located at the point b, the capacitance signal C_Fourof
Is it at point b just by size or at point a
On the other hand, it cannot be determined whether or not it is at point c in the opposite direction. This and
The capacitance signal C_FiveLike (it is an integral multiple of 180 °
I) The value of the signal having a phase shift, that is, the point b 'or
By detecting the magnitude of the signal at point c ',
Position direction relative to the
You.

FIG. 11 is a block diagram showing an embodiment of a recording / reproducing apparatus equipped with the positioning apparatus of the present invention. 11
Reference numeral 01 denotes all upper and lower plate electrodes for detecting the capacitance used for alignment. 1102 is a recording medium, 1
103 is a base electrode, 1104 is a recording medium substrate, 110
5 is a multi-probe chip 1106 and a recording medium chip 1
A z-direction and tilt drive mechanism for adjusting the distance and tilt between 107; 1108, an xyθ-direction fine movement drive mechanism;
09 is a z-direction drive circuit, 1110 is an xy-direction drive circuit,
Reference numeral 1111 denotes an xyθ coarse movement drive mechanism, 1112 denotes a rotation mechanism drive circuit, 1113 denotes a capacitance detection circuit for detecting the capacitance from the probe electrode 1115 and upper and lower plate electrodes 1101 provided on the recording medium 1102, and 1114 denotes a probe electrode. 1115 and a servo circuit for servoing the position of the recording medium 1102, and 1116 are the probe electrode 1115 and the recording medium 1.
A positioning circuit for determining the position of 102; a position detecting circuit 1117; a control circuit for centrally controlling the interaction between the blocks in the apparatus and a signal arithmetic processing;
Reference numeral 9 denotes a tunnel current detection circuit, 1120 denotes a write / read circuit for writing / reading write / read information according to an instruction from the control circuit 1118, and 1121 applies a pulse voltage for writing between the probe electrode 1115 and the base electrode 1103. A voltage application circuit 1122 for writing and reading data and applying a read voltage is an interface for performing input / output of write / read information, input of a control signal, output of an address signal, and the like.

Next, the operation will be described.

The current flowing between the probe electrode 1115 and the recording medium 1102 to which the bias voltage is applied is detected by the tunnel current detection circuit 1119, and the positioning circuit 1116, the servo circuit 1114, The distance between the probe electrode 1115 and the surface of the recording medium 1102 is feedback-controlled via the z-direction drive circuit 1109 and the z-direction drive mechanism 1105. The probe electrode 1115 is driven on the surface of the recording medium 1102 by the xy-direction drive circuit 1110 and the rotation mechanism drive circuit 1112 by the xy-θ coarse movement drive mechanism 1111 or the xyθ-direction fine movement drive mechanism 1108. The position of the probe electrode 1115 with respect to the recording medium 1102 in each of the x, y, z, and θ directions is detected by a position detection circuit 1117, and the detection output is output together with the output of the control circuit 1117.
16 and the servo circuit 111 as a positioning signal.
4 and the output of the servo circuit 1114 is output to the xy-direction drive circuit 1110, the z-direction drive circuit 1109, and the rotation mechanism drive circuit 1112. On the other hand, the capacitance between the position control electrodes in the x, y, z, and θ directions provided on the multi-probe chip 1106 and the recording medium chip 1107, respectively, changes according to the movement in each direction. And output to the control circuit 1118.
The control circuit 1118 performs not only centralized control of the interaction between the blocks in the apparatus, but also performs arithmetic processing such as the above-described division for normalization, subtraction and division when calculating the rotational position shift. .

The probe (shown at 103 in FIG. 1) on the multi-probe chip 1106 is a processing technique called micromachine or micromechanics (for example, K.K.
E, Peterson. “Silicon as a
Mechanical Material ", Pro
ceedings of the IEEE. 70 Vol. 4
20, 1982). FIG.
2 is a partial cross-sectional view of a configuration example of the probe. Reference numeral 1201 denotes a tunnel probe that applies a tunnel current or a recording signal to the recording layer. Reference numeral 1202 denotes a cantilever for moving the tunnel probe in the z direction, and is formed by micromechanics technology. And 1203
And 1204, the cantilever can be displaced by the electrostatic force. Reference numeral 1205 denotes a probe electrode having a tunnel probe on the cantilever, and 1206 denotes a substrate on which the probe electrode is formed.

Circuit elements such as a capacitance detection circuit on a recording medium chip and an oscillation circuit on a multi-probe chip can be easily formed by a conventionally known silicon semiconductor manufacturing technique.

As the recording medium, for example, a recording medium in which a material having a memory effect on the switching characteristics of voltage and current is formed on a support substrate is used. Here, a substrate obtained by epitaxially growing gold on a silicon substrate is used as a base electrode, and a monolayer of squarylium-bis-6-octylazulene molecules accumulated by an LB method on the electrode substrate is used as a recording medium. .

With the above arrangement, the relative positioning of the recording medium chip and the multi-probe chip, that is, the relative positioning of a plurality of probes with respect to the recording medium, is performed by using the positioning apparatus of the present invention, and the recording and reproducing of information is performed. As a result, a highly reliable operation without errors in the recording position and the reproduction position was realized.

[0037]

As described above, the three types of upper and lower portions for detecting the relative displacement in the x, y, and .theta. Directions are respectively provided on the multi-probe chip and the recording medium chip which move relatively in parallel. An electrode pair is provided, and the capacitance between the upper and lower electrodes that changes due to the change in the overlapping state is detected, and the multi-probe chip and the recording medium chip are set in the x direction so that these capacitances have a desired value. ,
By performing the relative driving in the y direction and the θ direction, the relative positioning of the multi-probe chip and the recording medium chip can be performed without lowering the accuracy.

[Brief description of the drawings]

FIG. 1 is a diagram showing an embodiment relating to a position control electrode in a positioning apparatus of the present invention.

FIG. 2 is a diagram showing a state in which upper and lower electrodes overlap when displacement occurs in the xy directions.

FIG. 3 is a waveform diagram of a capacitance signal for position control in the x (y) direction.

FIG. 4 is a waveform diagram of a position fine adjustment control capacitance signal and a synchronization detection signal.

FIG. 5 is a waveform diagram of a position control capacitance signal and a normalization signal when there is an inclination between a recording medium chip and a multi-probe chip.

FIG. 6 is a waveform diagram of a capacitance signal for position coarse adjustment control when there is a rotational position shift in the θ direction.

FIG. 7 is a waveform diagram of a position fine adjustment control capacitance signal when there is a rotational position shift in the θ direction.

FIG. 8 is a view showing an embodiment in which the lower electrode for position fine adjustment control is divided into two parts.

FIG. 9 is a waveform diagram of an electrostatic capacitance signal in a case where a lower electrode for position fine adjustment control divided into two is used.

FIG. 10 shows x, y, and x in the registration device of the present invention.
Conceptual diagram showing the configuration of the z, θ direction drive mechanism

FIG. 11 is a configuration diagram of a probe of an embodiment of a recording / reproducing apparatus equipped with the positioning apparatus of the present invention.

FIG. 12 is a partial cross-sectional view of a configuration example of a probe.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 101 Recording medium chip 102 Recording medium 103 Probe 104 Multi-probe chip 105 Upper electrode for z-direction position control 106 Upper electrode for z-direction position control 107 Upper electrode for z-direction position control 108 Upper electrode for z-direction position control 109 X-direction coarse position Upper electrode for adjustment control 110 Upper electrode for x-direction position fine adjustment control 111 Upper electrode for y-direction position coarse adjustment control 112 Upper electrode for y-direction position fine adjustment control 113 Upper electrode for θ-direction position coarse adjustment control 114 For θ-direction position fine adjustment control Upper electrode 115 Lower electrode for position control in z direction 116 Lower electrode for position control in z direction 117 Lower electrode for position control in z direction 118 Lower electrode for position control in z direction 119 Lower electrode for coarse position control in x direction 120 Fine position control in x direction Lower electrode 121 y-direction position coarse adjustment lower electrode 122 y-direction fine position Control lower electrode 123 θ-direction position coarse adjustment control lower electrode 124 θ-direction position fine adjustment control lower electrode 125 Oscillation circuit 126 Capacitance detection circuit 801 x (y) direction position fine adjustment control upper electrode 802 x (y) direction Lower electrode for position fine adjustment control 803 Lower electrode for x (y) direction fine position control 1000 Frame 1001 X direction coarse movement mechanism 1002 θ direction coarse movement mechanism 1003 Y direction coarse movement mechanism 1004 x direction fine movement mechanism 1005 θ direction fine movement mechanism 1006 y direction fine movement mechanism 1007 z direction and tilt drive mechanism 1008 motor 1009 piezo element 1101 upper and lower electrodes 1102 recording medium 1103 base electrode 1104 recording medium substrate 1105 z direction and tilt drive mechanism 1106 multi-probe chip 1107 recording medium chip 1108 xy θ direction fine drive Mechanism 1109 Direction drive circuit 1110 xy direction drive circuit 1111 xy θ direction coarse movement drive mechanism 1112 rotation mechanism drive circuit 1113 capacitance detection circuit 1114 servo circuit 1115 probe electrode 1116 positioning circuit 1117 position detection circuit 1118 control circuit 1119 tunnel current detection circuit 1120 write / read Circuit 1121 Voltage application circuit 1122 Interface 1201 Tunnel probe 1202 Cantilever 1203 Electrode 1204 Electrode 1205 Probe electrode 1206 Substrate

──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Masahiro Tagawa 3-30-2 Shimomaruko, Ota-ku, Tokyo Inside Canon Inc. (72) Inventor Yuji Kasukiki 3-30-2 Shimomaruko, Ota-ku, Tokyo Inside Canon Inc. (72) Katsunori Hatanaka 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (56) References JP-A-5-109131 (JP, A) JP-A-6-231493 (JP, A) JP-A-6-251434 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) G11B 9/14

Claims (9)

(57) [Claims] 1. A relative positioning device in an information recording / reproducing apparatus, wherein a first substrate having at least one recording / reproducing probe and a second substrate having a recording medium are moved in parallel in a substrate plane. The first, second, and third upper plate electrodes provided on the first substrate, and the first, second, and third upper plate electrodes are provided on the second substrate to face the first, second, and third upper plate electrodes, respectively. First, second, and third lower plate electrodes, and first, second, and third electrodes for detecting respective capacitances between the first, second, and third upper and lower plate electrodes. Detecting means, first driving means for relatively moving the first and second substrates in a first direction in the substrate plane, and second driving means orthogonal to the first direction in the substrate plane. Second driving means for relatively moving the first and second substrates in a direction, A third driving unit for relatively rotating the first and second substrates around an axis in a third direction orthogonal to the second directions; and a first driving unit for driving the first substrate. Detecting a driving amount difference between a first position at which the capacitance has a predetermined value and a second position at which the third capacitance has a predetermined value; From the ratio of the center distance between the lower plate electrode and the third upper and lower plate electrodes, the first and second positions about the axis in the third direction are determined.
Calculating the amount of relative rotational position deviation of the substrate, driving the third driving means so as to correct the relative rotational position deviation, and setting the first and second capacitances to predetermined values, respectively. And a control means for driving the first and second driving means. 2. The relative positioning device according to claim 1, wherein a fourth upper plate electrode provided on the first substrate, and a second upper plate electrode facing the fourth upper plate electrode. A fourth lower plate electrode provided; fourth detection means for detecting a capacitance between the fourth upper and lower plate electrodes; a detection result of the fourth detection means; Second, third
And a control means for calculating the ratio of the detection result to each of the detection means, and for driving the first, second, and third drive means based on each calculation result. Relative alignment device. 3. The relative positioning device according to claim 1, wherein the first, second, and third upper and lower plate electrodes are each composed of two plate electrodes for coarse adjustment and fine adjustment. The first, second, and third detection means respectively detect the coarse adjustment detection means for detecting the capacitance between the upper and lower plate electrodes for coarse adjustment, and the capacitance between the upper and lower plate electrodes for fine adjustment. The first, second, and fine adjustment detecting means for detecting.
A third drive unit for coarsely moving the first and second substrates relative to each other based on the detection result of the coarse adjustment detection unit and a coarse rotation drive unit for relatively rotating the first and second substrates; And a fine movement driving means for relatively moving the first and second substrates based on a detection result of the means and for relatively rotating the fine movement. 4. The relative positioning device according to claim 3, wherein each of the first and third coarse adjustment upper and lower plate electrodes has a length in the second direction of one of the plate electrodes. Is larger than the length of the other plate electrode in the second direction by a first predetermined amount, and the first and second substrates are larger than the first predetermined amount in the second direction. When a small relative displacement occurs, the capacitance value between the first and third upper and lower plate electrodes is prevented from decreasing, and the capacitance value of the second coarse adjustment upper and lower plate electrodes is reduced. In each of the shapes, the length of one of the plate electrodes in the first direction is larger than the length of the other plate electrode in the first direction by a second predetermined amount. And the second
When the substrate has a relative displacement of less than the second predetermined amount in the first direction, the value of the capacitance between the second upper and lower plate electrodes does not decrease. A relative positioning device. 5. The relative positioning device according to claim 3, wherein each of the first and third fine adjustment upper and lower plate electrodes has a length in the first direction in the second direction. A plurality of flat electrodes shorter than the length of
The shape of each of the second fine-adjustment upper and lower plate electrodes is a comb shape having its ends connected, and a plurality of plate electrodes whose length in the second direction is shorter than the length in the first direction. A relative alignment device, which is arranged at a second interval and has a comb shape with its ends connected. 6. The relative positioning apparatus according to claim 1, wherein said first and second substrates are relatively moved in said first and second directions by first and second minute vibrations, respectively. Of the first and second micro-vibration means, and the respective outputs from the first and second detection means,
First and second synchronization detecting means for detecting a component synchronized with the first and second minute vibrations, and a component synchronized with the first minute vibration among outputs from the third detecting means. Third synchronization detecting means for detecting, and driving the first and second driving means based on the detection results from the first and second synchronization detecting means, respectively.
Control means for driving the third drive means based on detection results from the first and third synchronization detection means. 7. The relative positioning device according to claim 1, wherein one of the first, third upper and lower plate electrodes is divided in the first direction. Wherein the first and third detecting means are provided with two capacitances between the first and third two-divided plate electrodes and the other plate electrode. A first and a third independent detecting means for detecting each of the second and third plate electrodes independently of each other, wherein one of the second upper and lower plate electrodes is divided in the second direction. Wherein the second detecting means comprises second independent detecting means for independently detecting two capacitances between the second two-part plate electrode and the other plate electrode; , The two electrostatic sensors detected by the second and third independent detecting means, respectively. The difference in the amount calculated respectively, calculated the results based on the first, second, relative alignment device, characterized in that it comprises a control means for driving the third of the drive means. 8. The relative positioning device according to claim 7, wherein the first direction of the first and second substrates is determined based on two capacitance values detected by the first independent detection unit. A first misalignment direction detecting means for detecting an orientation of the relative misalignment; and a second capacitance value of the first and second substrates based on two capacitance values detected by the second independent detection means. A second misalignment direction detecting means for detecting the direction of the relative misalignment with respect to the direction, and a second misalignment direction detected by the first and third independent detecting means.
A third displacement detecting a direction of a relative rotational displacement of the first and second substrates around an axis in a third direction orthogonal to the first and second directions from the two capacitance values; An orientation detection unit, and a control unit that drives the first, second, and third driving units based on detection results from the first, second, and third displacement direction detection units. A relative positioning device, comprising: 9. A relative alignment method in an information recording / reproducing apparatus, wherein a first substrate having at least one recording / reproducing probe and a second substrate having a recording medium are moved in parallel in a substrate plane. The first, second, and third upper plate electrodes provided on the first substrate, and the first, second, and third upper plate electrodes are provided on the second substrate to face the first, second, and third upper plate electrodes, respectively. First, second, and third lower plate electrodes, and first, second, and third electrodes for detecting respective capacitances between the first, second, and third upper and lower plate electrodes. Detecting means, first driving means for relatively moving the first and second substrates in a first direction in the substrate plane, and second driving means orthogonal to the first direction in the substrate plane. Second driving means for relatively moving the first and second substrates in a direction, Third driving means for relatively rotating the first and second substrates around an axis in a third direction orthogonal to each of the second directions, and driving the first driving means, A driving amount difference between a first position at which the first capacitance becomes a predetermined value and a second position at which the third capacitance becomes a predetermined value; The first substrate and the first substrate with respect to an axis perpendicular to the first direction and the second direction are determined from a ratio of a center-to-center distance between the upper and lower plate electrodes and the third upper and lower plate electrodes. Calculating the amount of relative rotational position deviation of the second substrate, and driving the third driving means based on the detection results of the first and third detecting means so as to correct the relative rotational position deviation. Driving the first drive unit based on the detection result of the first detection unit so that the first capacitance is set to a predetermined value; And driving the second drive means based on the detection result of the second detection means so that the second capacitance is set to a predetermined value.