JPH0612710A - Method for driving cantilever type displacement element, scanning type tunnel microscope, information process device and cantilever type displacement element - Google Patents

Abstract

PURPOSE:To obtain a displacement quantity of good accuracy at a high speed by providing an electrode for electrostatic driving in parallel with an electrode to form a parallel flat plate capacitor with the electrode for piezoelectric driving and applying a voltage thereto, thereby controlling the vibration of the displacement element. CONSTITUTION:The cantilever type displacement element is constituted by sticking the bimorph cantilever type displacement element which is formed by laminating the electrode 5, a piezoelectric thin film 4, the electrode 6, the piezoelectric thin film 8 and the electrode 9 in this order on an Si substrate 12 and the electrode 11 for electrostatic driving below the rear surface of the cantilever on the substrate 2 to each other. The parallel flat plate capacitor is formed of the electrode 5 and the electrode 11. The electrode 9 and electrode 5 of the cantilever part are short-circuited and an impressing power source 19 for piezoelectric driving is connected to the electrode 6. The electrode 6 is held grounded. The limitation of the displacement quantity and generating power of the cantilever type displacement element by the electrostatic force of the parallel flat plate part is enabled by maintaining the power source 16 at a suitable voltage.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cantilever (cantilever) type displacement element driven by an inverse piezoelectric effect and a scanning tunneling microscope (hereinafter referred to as "STM") using the same.
The present invention relates to an information processing device.

[0002]

2. Description of the Related Art Conventionally, a cantilever type displacement element of this type is known as shown in FIG.

The cantilever type displacement element 91 used here has a laminated structure formed of piezoelectric thin films 4 and 8 formed of electrically polarized PZT and electrodes 5, 6 and 9. There is. This cantilever type displacement element is of a cantilever type fixed by a support 92. Here, when a voltage is applied to the electrodes 5, 6 and 9 in the contracting direction, the expanding direction and the opposite direction of the piezoelectric thin films 4 and 8, respectively, the piezoelectric thin films 4 and 8 are curvedly displaced upward or downward. This curved displacement allows the free end 93 to be displaced in the vertical direction.

In recent years, with the background of semiconductor process technology, mechanical electric elements (micromechanics) such as semiconductor pressure sensors, semiconductor acceleration sensors, and microactuators using semiconductors as mechanical structures have come into the limelight. It was

As a feature of such an element, it is possible to provide a small-sized and highly precise mechanical mechanism component and to integrate the element and an electric circuit on a Si wafer because a semiconductor wafer is used. Further, by manufacturing the semiconductor process as a base, it can be expected that the productivity is improved by batch processing of the semiconductor process. In particular, a cantilever type displacement element using a piezoelectric thin film can be mentioned. Since it can control extremely fine movement, it is applied to an STM that can directly observe the atomic level and the molecular level. For example, an STM probe (IEEE) using a cantilever type displacement element proposed by Kuwait et al. Of Stanford University
E Micro Electro Mechanical
al Systems, p188-199, Feb. 1
990). As shown in FIG. 10, the back surface of the wafer of the Si substrate (wafer) 1 is partially removed to form a silicon membrane, and thin films of Al94 and ZnO95 are sequentially laminated on the surface to form a bimorph cantilever,
By removing the silicon membrane and the etching protection layer (silicon nitride film) on the wafer surface from the back surface by reactive dry etching, a bimorph cantilever type displacement element for STM probe displacement is manufactured. A tunnel current detection probe 10 is attached to the free end of the upper surface of the cantilever, and a good STM image is obtained.

On the other hand, by using the STM method, atomic order and molecular order observation and evaluation of semiconductors or polymer materials and fine processing (EE Ehrichs, 4th In
international Conference on
Scanning Tuning Micro
copy / Spectrocopy, '89, S1
3-3), and application of the recording / reproducing apparatus to various fields has been studied. In particular, there is an ever-increasing demand for recording devices with a large capacity for computer calculation information and the like, and due to advances in semiconductor process technology, microprocessors have become smaller and computational power has improved. It is rare. In order to meet these requirements, recording is performed by changing the shape of the surface of the recording medium by applying a voltage from a converter consisting of a tunnel current generating probe that is present on a driving means whose distance from the recording medium can be finely adjusted. An information processing apparatus has been proposed in which information is read by writing and detecting a change in tunnel current due to a change in shape, and the minimum recording area becomes 10 nm square (USP4575752).

[0007] The STM utilizes the tunnel effect in which a current flows through a barrier between a sharp conductive probe and a sample surface that are several nm or less in distance. [G. Binnig et al. , Helvet
ica Physica Acta, 55, 726 (1
982), U.S. Pat. No. 4,433,993]].

An apparatus for performing high-density information processing (recording / reproducing) by applying this STM principle is disclosed in Japanese Patent Laid-Open No. 63-161.
No. 552, JP-A No. 63-161553, and the like. This uses a probe similar to the STM and changes the voltage applied between the probe and the recording medium to perform recording.

Conventionally, as a probe forming method used in these recording / reproducing apparatuses, a processing technique [K. E. Peterson “Silicon as
a MechanicalMaterial ”, Pr
oceding of the IEEE, 70
(5), 420-457 (1982)] was known. An STM constructed by such a method is disclosed in
It is proposed in JP-A 1-206148.

This is to form a parallel spring which can be finely moved in the XY directions by fine processing using single crystal silicon as a substrate.
Further, a cantilever portion having a probe formed thereon is provided in the movable portion, and an electric field is applied to the cantilever portion and the bottom portion so that the cantilever portion is displaced in the direction Z perpendicular to the plane of the substrate by electrostatic force.

[0011]

The conventional cantilever type displacement element has no means for particularly restricting the displacement amount or the operating force of the displacement element. Especially when the cantilever type displacement element is used as an STM probe, its displacement amount and operating force become very important. The STM is to observe the unevenness of the sample by bringing the needle tip close to the sample up to several Å and monitoring the tunnel current flowing between them. Therefore, it is desirable for the STM probe to make small displacements at high speed and with high accuracy. For this reason, the conventional cantilever type displacement element does not have a means for restricting and controlling the displacement amount and the operating force, and therefore the characteristics of the cantilever type displacement element are uniquely determined, so that the desired displacement amount can be accurately determined. It was difficult to control.

Further, in the information processing apparatus applying the STM, the information on the recording medium is a bit formed by a physical change such as a bit due to unevenness on the recording medium by applying an electric pulse from the STM probe. Is recorded as. In such a case, the STM probe must be positioned at a desired position and distance from the recording medium. In the information processing apparatus using such a method, the STM probe attached to the free end of the cantilever type displacement element positions the piezoelectric body with various applied voltages that change with time in order to perform positioning with the recording medium. I have to give. For example, when a rectangular wave voltage is applied, the cantilever type displacement element responds to the rectangular wave and also generates unnecessary vibration whose main component is the natural frequency.
Until the unnecessary vibration is dampened, the next operation cannot be performed, so that the speeding up of the information processing device is suppressed. Unnecessary vibration needs to be removed or attenuated as much as possible. For this reason, it is usual to sandwich the cantilever with a rubber or the like having a damper effect on the supporting portion. However, in a cantilever type displacement element manufactured by a thin film technique and an etching technique by a semiconductor process, such an attempt can be said to be difficult due to its structure.

[0013]

The object of the present invention is to (1) have a high-speed and accurate displacement amount.

(2) Unnecessary vibration is removed to increase the speed.

The above is the object of the present invention. In order to achieve this, a cantilever type displacement element and its driving method, ST
M, to provide an information processing device.

That is, the first aspect of the present invention comprises at least one layer of piezoelectric material for changing the cross-sectional shape of the cantilever in a plane orthogonal to the longitudinal direction, and an electrode for applying a voltage to the piezoelectric material. In a cantilever type displacement element, an electrostatic drive electrode is provided in parallel with the electrode, a parallel plate capacitor is formed with the piezoelectric body drive electrode, and a voltage is applied to the parallel plate capacitor so that the displacement element vibrates. A driving method of a cantilever type displacement element characterized by controlling, a second is an STM using the driving method, and a third is an information processing apparatus using the driving method.

According to this structure, the cantilever type displacement element can suppress the displacement amount and the generated force of the displacement element by the electrostatic force applied to the parallel plate capacitor, and can control the desired minute displacement amount with high accuracy. Further, as a result of suppressing the generated force by electrostatic force, it works as a damper effect, and unnecessary vibration can be removed.

Further, a fourth aspect of the present invention is a cantilever type displacement element comprising a piezoelectric body and electrodes for applying a voltage to the piezoelectric body, which are driven by the piezoelectric body on the upper and lower surfaces of the piezoelectric body. Is a cantilever-type displacement element, characterized in that a vibration absorption electrode is provided in an insulated state, respectively, and a pair of upper and lower vibration absorption electrodes are electrically connected. A cantilever type displacement element multi-arranged on the same silicon single crystal substrate, a sixth STM using a fourth cantilever type displacement element, and a seventh information processing apparatus.

According to the above structure, the electric charge generated on the surface due to the piezoelectric effect due to the deformation is converted into a current flowing between the pair of upper and lower vibration absorbing electrodes. As a result, the energy of elastic vibration is converted into electric energy and finally becomes Joule heat. Therefore, it is possible to significantly reduce the vibration damping time.

Further, by providing the pair of upper and lower vibration absorbing electrodes on the left and right of the cantilever portion and electrically connecting them to each other, not only bending vibration in the long axis direction but also elastic vibration in the width direction and the diagonal direction are converted into electric energy. It can be absorbed and high-speed and high-precision displacement control is possible. Further, by removing harmful vibrations in this way, it has become possible to realize a probe for STM with high accuracy and high speed.

Further, by integrating a plurality of devices on the same substrate,
A small and highly accurate STM system having a multi-probe can be constructed, and by using a Si single crystal as a substrate, semiconductor elements such as transistors and diodes can be integrated at the same time.

It has also become possible to provide an information processing apparatus capable of high-capacity and high-density recording / reproduction using a medium whose state is changed by voltage application as an STM observation target.

[0023]

EXAMPLES The present invention will be described in detail below with reference to examples.

Example 1 This example shows a cantilever type displacement element using the first driving method of the present invention.

FIG. 1A shows a perspective view of a cantilever type displacement element of this embodiment. This is manufactured on a Si substrate by a normal IC manufacturing process and Si anisotropic etching. FIG. 1B is a schematic diagram of a cross-sectional view of a cantilever displacement element. The electrode 5 on the Si substrate 12,
The piezoelectric thin film 4, the electrode 6, the piezoelectric thin film 8 and the electrode 9 are laminated in this order, and a bimorph cantilever type displacement element and an electrostatic drive electrode 11 bonded to the lower rear surface of the cantilever on the Si substrate. It Incidentally, the electrode 5 and the electrode 1
And 1 form a parallel plate capacitor. Reference numeral 10 is a probe for detecting a tunnel current.

FIG. 2 is a manufacturing process drawing of the above-described cantilever type displacement element. First, the cantilever portion will be described (FIGS. 2A to 2D). First, Si with a thickness of 250 μm
On the (100) substrate 1, 500 Å of silicon nitride films 2 and 3 are laminated by the LP-CVD method and patterned by photolithography to form an etching mask. Then, 1000 Å of Au electrode 5 was laminated by the resistance heating method and patterned. Further, the piezoelectric ZnO thin film 4 is made to have a thickness of 1 μm by the RF magnetron sputtering method, and Au by the resistance heating method.
The electrode 6 is set to 1000 Å and the piezoelectric material ZnO is again formed by the sputtering method.
The thin films 8 were laminated in a thickness of 1 μm and patterned (FIG. 2).
(A)). Subsequently, 1000 Å of the Au extraction electrode 9 was deposited by the resistance heating method and patterned. An STM probe 10 for detecting a tunnel current formed of Pt was formed on the top of the STM probe 10 (FIG. 2B).
After that, anisotropic etching of Si was performed with a KOH solution to prepare a cantilever (FIG. 2C). Finally,
The silicon nitride film was removed by the reactive ion etching method (FIG. 2 (d)).

Next, the parallel plate capacitor section side will be described (FIGS. 2E to 2H). First, the thickness is 250 μm
A thermal oxide film 13 of Si was formed on the Si (100) substrate 1 ′ of about 1000 Å (FIG. 2E). Next, LP-
2000 Å of silicon nitride film 14 was laminated by the CVD method and patterned to form an etching mask (see FIG. 2).
(F)). Then, the Au electrode 11 is set to 1 by the resistance heating method.
000Å was laminated and patterned (Fig. 2 (g)). Furthermore, anisotropic etching of Si by KOH solution,
A trapezoidal substrate was formed. Here, the etching depth is about 2
It was 20 μm (FIG. 2 (h)). Finally, the cantilever portion (FIG. 2 (d)) and the base body (FIG. 2 (h)) were bonded by anodic bonding to form the parallel plate capacitor portion 15 (FIG. 2 (i)).

The cantilever type displacement element is rectangular and has a length of 3
The size was 00 μm × width 100 μm, thickness was about 2.2 μm, the opposing area of the electrode 5 and the electrode 11 of the parallel plate capacitor part 15 was 300 μm × 100 μm, and the interval was about 30 μm.

The displacement characteristics of the cantilever type displacement element when no applied voltage was applied to the parallel plate capacitor section at this time were as follows.

Natural frequency 20 KHz Displacement amount 0.25 μm / V (Displacement amount at free end with respect to piezoelectric unit applied voltage) Mechanical Q value at natural vibration 56 Next, a method of driving the cantilever displacement element of the present invention will be described. . FIG. 3 is a schematic connection diagram thereof. The upper electrode 9 and the lower electrode 5 of the cantilever portion are short-circuited, and the piezoelectric body driving application power source 19 is connected to the middle electrode 6. The middle electrode 6 is grounded. Next, the electrostatic force variable DC power source 16 of the parallel plate capacitor section is connected as shown in FIG. Reference numeral 17 denotes a current-voltage conversion amplifier, and 18 denotes a tunnel current signal output. By setting the variable DC power supply 16 to an appropriate voltage, the displacement amount and the generated force of the cantilever type displacement element can be limited by the electrostatic force of the parallel plate portion.

FIG. 4 shows the relationship between the piezoelectric body driving voltage and the tip displacement of the free end of the cantilever portion due to various electrostatic force applied voltages. It can be understood that the inclination of the displacement amount of the cantilever changes depending on the electrostatic force applied voltage, and the displacement amount per unit applied voltage of the piezoelectric body can be controlled by the electrostatic force applied voltage. The difference in the displacement of the cantilever is that the intercept is
This is because the cantilever portion is slightly curved by the electrostatic force. By providing the parallel plate capacitor in this way, the inclination of the displacement amount in the piezoelectric body applied voltage can be changed, so that various minute displacement amounts can be controlled and accurate positioning can be performed.

FIG. 5A shows the frequency response of various electrostatic force applied voltages when the piezoelectric applied voltage is fixed and a sinusoidal piezoelectric applied voltage is applied. The frequency response at this time was as follows.

Electrostatic force applied voltage 0V Natural frequency 20KHz Mechanical Q value 56 Electrostatic force applied voltage 10V Natural frequency 25KHz Mechanical Q value 6 By changing the electrostatic force applied voltage in this way, the natural frequency is increased, I was able to reduce the target Q value.

FIG. 5B shows a rectangular wave (1
(msec) is a view showing the response of the displacement amount under various electrostatic force applied voltages. When the electrostatic force applied voltage was 0 V, unnecessary vibration having a natural frequency as a main component was observed, and it took about 0.6 msec to attenuate. However, electrostatic force applied voltage 1
It can be seen that no unnecessary vibration is observed at 0 V, and a high-speed response is possible.

As described above, a cantilever type displacement element having high-speed response, accurate displacement amount, and unnecessary vibration could be formed. Further, when desired responsiveness and a desired amount of displacement are required, the length of the cantilever displacement element may be changed, the material of the piezoelectric thin film may be changed, and the thickness may be changed. While it is using ZnO film as the piezoelectric thin film in the present embodiment, which, PbTiO _3, P
Other piezoelectric materials such as ZT, AlN, Ta ₂ O ₅ and PLZT may be used.

Example 2 An STM apparatus using the cantilever type displacement element of Example 1 will be described. FIG. 6 shows a block diagram of the STM of this embodiment. An XY scanning mechanism 62 is installed on the anti-vibration table 61, and the sample 63 of the observation object is movable in the XY directions. Also, Z
The cantilever type displacement element according to the present invention is installed on the coarse movement mechanism 64, and the STM probe 66 is produced at the tip of the cantilever. The XY scanning mechanism 62 is driven by an XY driving circuit 67, and the Z coarse movement mechanism 64 is driven by a Z driving circuit 70. Further, the cantilever 65 can change the displacement characteristic by the electrostatic force application voltage circuit 71. The piezoelectric drive (feedback) circuit 72 provides feedback in the Z direction so that the tunnel current value flowing between the sample 63 and the STM probe 66 becomes constant. A bias voltage is applied between the sample and the STM probe by the bias applying circuit 68 and detected by the tunnel current detecting circuit 69. All the circuits are uniformly controlled by the microcomputer 73, and the observation result is displayed on the display device 74.

In this example, an Au thin film epitaxially grown was used as a sample. At this time, 1 μm x 1
STM observation of the μm region was performed. First, the electrostatic force applied voltage circuit 71 causes S to be 0V at an X-direction scanning speed of 100 Hz.
TM observation was performed. Next, when the electrostatic force applied voltage was set to 5 V, an equivalent image was obtained even at an X-direction scanning speed of 200 Hz. According to this method, an STM that can obtain a clear image at high speed
Is obtained.

Example 3 In this example, an information processing apparatus using the cantilever type displacement element of Example 1 will be described. FIG. 7 is a block diagram of the information processing apparatus of this embodiment. X on the seismic isolation table 61
A Y scanning mechanism 62 is installed, and a recording medium 75 is further installed on the Y scanning mechanism 62. The XY scanning mechanism 62 is driven by an XY drive circuit 67, and various biases or pulse voltages for writing, reading and erasing recording bits are applied to the recording medium 75 by a bias applying circuit 68. Z coarse movement mechanism 6 capable of coarse movement by Z axis drive circuit 70
A plurality of 10 mm square multi-cantilever displacement elements 76 are installed on the surface 4, and 4 × 3 = 12 cantilevers 77 are installed. An STM probe 66 is provided at the free end of each cantilever. Each S
The tunnel current flowing through the TM probe is detected by the tunnel current detection circuit 69, and each cantilever is driven by the piezoelectric drive (feedback) circuit 72. Further, the displacement characteristic can be controlled by the electrostatic force applied voltage circuit 71. All circuits are controlled by the microcomputer 73. The recording medium 75 is an Au thin film (2500Å) epitaxially grown on a mica substrate.
What laminated | stacked the organic recording layer on the top was used. As the organic recording layer, an LB film of squarylium-bis-6-octiazulene (one layer) was used. The method for forming the LB film is
The method disclosed in JP-A-63-161552 was followed.

Next, a recording / reproducing method will be described. First, with one of the STM probes on the + side and the Au thin film on the-side, a pulse voltage (shown in FIG. 8) of a threshold voltage V _th ON or more at which the recording layer changes to a low resistance state (ON state) is applied. Then, the ON state was generated. While maintaining the distance between the STM probe and the recording layer, 1 is provided between the probe and the Au thin film.
When the tunnel current was measured by applying a voltage of V,
It was confirmed that a current of about 0.5 mA flowed and that it was in the ON state.

Next, recording was performed one after another using this information processing apparatus. First, with the electrostatic force applied voltage set to 0 V, 12 cantilevers were sequentially driven at a speed of 10 msec per bit for one cantilever for recording. It was then possible to read this information at the same speed. At this time, no recorded bit error was observed. Next, the same experiment was conducted at a speed of 5 msec per bit, and thereafter, when reproduction was performed, an error of about 1% in the recorded bit was detected. However, when the electrostatic force applied voltage was set to 5 V and a similar experiment was performed, no error was found in the recording bit.

Embodiment 4 FIG. 11 is a configuration diagram best showing the features of the cantilever type displacement element of the present invention, and FIG. 11 (b) is a sectional view taken along the line AA ′ in FIG. 11 (a).

In this drawing, 111 is a substrate, and 112
Is a lower electrode, 113a is a lower piezoelectric thin film, 113b is an upper piezoelectric thin film, 114 is an intermediate electrode, 115 is an upper electrode,
116a, 116b, 116c and 116d are vibration absorbing electrodes.

Here, the piezoelectric thin films 113a and 113b are formed so that the polarization axes are oriented in the direction indicated by the arrow 117, and can be expanded or contracted by applying a voltage.
As a result, the cantilever portion 118 is bent and displaced. The electrodes 112, 114, 115 are drawn out to the outside so that a drive voltage can be applied from the outside.

Vibration absorbing electrodes 116a, 116d and 1
16b and 116c are electrically connected on the substrate 111. With such a structure, the cantilever portion 1
It is possible to electrically absorb unnecessary vibration that occurs when the 18 is displaced.

The principle will be described below. Electrode 112,
When a predetermined voltage is applied to 114 and 115 to bend and displace the cantilever portion 118, the cantilever portion 118 vertically vibrates around a target displacement amount. The state at this time is shown in FIG. This vibration deforms the piezoelectric thin films 113a and 113b, so
Electric charges are generated on the surfaces of 13a and 113b due to the piezoelectric effect. At this time, the lower surface of the piezoelectric thin film 113a and 11
Since the compressive deformation and the expansive deformation alternately occur on the upper surface of 3b, the negative signs of the generated charges are always opposite.

The vibration absorbing electrode 116 according to the present invention
a, 116b, 116c, 116d are piezoelectric thin film 113
It is provided on the surface of a, 113b, and electrically connects 116a and 116d and 116b and 116c, which are vertically opposed to each other with the piezoelectric body interposed therebetween. As a result, the electric charges generated by the piezoelectric effect are transmitted to the vibration absorbing electrodes 116a and 116d and 116b and 1
It makes a current between 16c and reciprocates. Therefore, a part of the vibration energy is converted into electric energy, so that the vibration damping can be accelerated.

Vibration absorbing electrodes 116a, 1 according to the present invention
FIG. 12B shows the displacement characteristic of the cantilever portion 118 when 16b, 116c, and 116d are provided.

As described above, by using the vibration absorbing electrode, the displacement control of the cantilever type displacement element can be performed more accurately.

Next, an example of a method of manufacturing the cantilever type displacement element according to this embodiment will be described with reference to FIGS. 13 (a) to 13 (f).

First, a Si ₃ N ₄ film of 150 is formed on a single crystal silicon substrate 111 having a plane orientation (100) by a low pressure CVD method.
A substrate having a film thickness of 0Å and an insulating layer 119 formed thereon is used as a substrate. Next, in order to secure adhesion, Cr is vapor-deposited in a volume of 5 to 10 liters and then Au is deposited in a volume of 1000 liters to form a metal film.
A photosensitive resist is applied on this metal film and general photolithography is performed to remove unnecessary portions of Au / Cr by etching to remove the lower electrode 112 and the vibration absorbing electrodes 116c and 116.
d is patterned (FIG. 13A).

Next, ZnO is formed thereon by the sputter deposition method.
To form a piezoelectric thin film 113a.
At this time, the piezoelectric polarization axis (C axis) and its polarity can be aligned by appropriately adjusting the conditions of sputter deposition (FIG. 13B).

Next, Au is deposited on the piezoelectric thin film 113a again by the vacuum evaporation method to a thickness of 1000 liters. After that, a photosensitive resist is applied, photolithography is performed, and unnecessary portions are removed by etching to form a pattern of the intermediate electrode 114 (FIG. 13C).

Next, in the same manner as in the step of FIG. 13B, 5000 Å of ZnO was formed by the sputter deposition method, and the piezoelectric thin film 1 was formed.
13b is formed (FIG. 13D).

Again, 1000 liters of Au is formed and patterned by photolithography to form the upper electrode 115 and the vibration absorbing electrodes 116a and 116b. After that, photolithography is performed again to remove unnecessary portions of ZnO by etching (FIG. 13E).

Next, anisotropic etching is carried out from the back surface of the Si single crystal substrate 111 by utilizing the fact that the etching rate greatly differs depending on the plane orientation, and the Si ₃ N ₄ insulating layer 119 is formed.
Si is removed to the position. Next, the Si ₃ N ₄ film is removed by reactive ion etching to remove the cantilever portion 11
8 is formed (FIG. 13F).

The etching solution used for the photolithography here is a KI: I ₂ aqueous solution for Au, a (NH ₄ ) ₂ Ce (NO ₃ ) ₆ : HClO ₄ aqueous solution for Cr,
An acetic acid aqueous solution was used for ZnO. A KOH aqueous solution was used for anisotropic etching of Si, and CF ₄ gas was used for reactive ion etching.

An example of the dimensions and drive characteristics of each part of the cantilever type displacement element manufactured in this embodiment is shown below.

Cantilever portion 118 has a length of 500 μm and a width of 50 μm. The voltage applied to the lower electrode 112 and the upper electrode 115 is ± 3 V with the intermediate electrode 114 as the ground. The amount of displacement at the tip of the cantilever portion 118 is ± 2 V.
μm Unwanted vibration damping time 10 msec By using the present invention as described above, it is possible to greatly reduce the damping time of unnecessary vibration generated in the cantilever type displacement element, and it is possible to greatly improve the accuracy in position control.

Although ZnO is used as the piezoelectric material in this embodiment, it is not limited to ZnO.
1N, PZT, BaTiO ₃ , LiNbO ₃ , PVDF
Similar effects can be obtained by using other piezoelectric materials. Although Au and Cr are used as electrode materials, Pt, Pd,
Similar effects can be obtained by substituting other conductive materials such as Ti, W, and Al.

The manufacturing method is not particularly limited, and it can be formed by other methods.

Embodiment 5 FIG. 14 shows a fifth embodiment of the present invention. FIG. 14B is a sectional view taken along the line BB ′ in FIG. In this embodiment, the lower electrode is a cantilever type displacement element having a structure in which the lower electrode 112a and 112b and the upper electrode are divided into 115a and 115b.
By inverting the negative signs of the voltages applied to and 112b and 115b, in addition to the bending displacement in the vertical direction of the fourth embodiment, it is also a displacement element that enables a slight horizontal displacement.

In this embodiment, the vibration absorbing electrode 116 is used.
a, 116b, 116c, 116d are 116a and 11
In addition to electrically connecting 6d, 116b and 116c, 116a and 116b and 116c and 116d are electrically connected at the tip of the cantilever portion 118.

With such a structure, not only the bending vibration in the length direction of the cantilever portion 118 in the fourth embodiment, but also the parasitic vibration in various modes such as the vibration in the width direction of the cantilever portion 118 and the vibration in the diagonal direction are electrically generated. It becomes possible to be absorbed.

The displacement element having such a structure can be manufactured only by changing the pattern of the photomask when performing photolithography in the manufacturing method shown in the fourth embodiment.

In the present embodiment and the fourth embodiment, the vibration absorbing electrodes 116a and 116d and 116b and 116c are electrically connected on the substrate 111, but the connection position and method are not limited to this. Instead, as shown in FIG. 15, the through holes 1 are formed in the piezoelectric thin films 113a and 113b.
It is also possible to form 20 and electrically connect there.

As shown in FIG. 16, the cantilever portion 1
Similar effects can be obtained by forming the side surface electrode 121 on a part or all of the side surface of 18.

When the voltage applied to the intermediate electrode is only the ground, the structure is such that the intermediate electrode 114 is connected through the through hole 120 as shown in FIG. 17, or the side electrode 121 is connected to the intermediate electrode 114 as shown in FIG. The structure which does is also possible. With such a structure, the charge generated on the surface by the piezoelectric effect can be more effectively consumed as a current, and the efficiency of vibration absorption is improved.

Sixth Embodiment A sixth embodiment of the present invention is shown in FIGS. FIG. 19
19B is a sectional view taken along the line CC ′ in FIG. 19A, and FIG. 20 is a rear view of FIG. 19A.

In this embodiment, in addition to the structure of the fifth embodiment, a lead electrode 122 is newly provided on the piezoelectric thin film 113b, and a conductive probe 123 connected to the lead electrode 122 is provided at the tip of the cantilever portion 118. .

By thus providing the conductive probe 123 at the tip, the cantilever type displacement element according to the present invention can be used as a probe of STM. That is, by applying a predetermined drive voltage to each electrode, the cantilever portion 118
Is bent and displaced to bring the probe 123 closer to the surface of the observation target. When the surface has conductivity, a tunnel current flows between the probe 123 and the surface when the distance between the probe 123 and the surface approaches a few nm. This tunnel current is
Since it changes exponentially with the distance between the tip of 23 and the surface, this tunnel current is taken out through the extraction electrode 122 for amplification, and by feeding back to the drive voltage of the cantilever portion 118, the tip of the probe 123 is The distance to the surface can be kept constant. By moving the cantilever portion slightly in the x and y directions in such a state, it is possible to observe the irregularities of the extremely small surface, the distribution of electric resistance, and the like from the change in the feedback voltage. The vibration absorbing electrodes 116a, 116b according to the present invention,
By providing 116c and 116d, it is possible to suppress the generation of harmful vibrations and perform accurate feedback, so that the resolution of the STM can be improved.

Such a probe can be manufactured by changing the pattern of the photomask of the photolithography in the manufacturing method shown in the fourth embodiment. In addition, the conductive probe 123 is formed by applying a photoresist 5 after forming the upper electrode.
The resist was removed only at the position where the probe 123 was formed by applying μm and the film was formed by a combination of oblique evaporation and substrate rotation. This method is known as a means for forming a microstructure having a high aspect ratio.

Embodiment 7 FIGS. 21 and 22 show a seventh embodiment of the present invention. A plurality of cantilever actuators having the probe 123 described in the sixth embodiment are manufactured on the same silicon substrate 111 to manufacture the integrated actuator 211.

Such an integrated actuator may be obtained by expanding the photolithographic pattern in the manufacturing method described in the fourth and fifth embodiments. In this way, multiple cantilevers can be formed simultaneously on the same substrate,
The dimensional accuracy is very high, and the variation in characteristics between the cantilevers can be suppressed to a very small level.

Further, by using Si single crystal as the substrate, semiconductor elements such as transistors and diodes can be integrated on the same substrate, and an amplifier for tunnel current amplification and cantilever drive can be integrated. it can.

FIG. 21 is a diagram schematically showing an STM device using the integrated actuator of this embodiment. As a result, the integrated actuator 211 is used and the sample 222
It is possible to simultaneously observe STM images of a plurality of minute regions on the surface of the. In the figure, 221 and 223 are x,
a movable stage having a coarse movement mechanism in the y and z directions,
The integrated actuator 211 is fixed to the movable stage 221, and the sample 222 is fixed to the movable stage 223.

An example of the dimensions of the integrated actuator manufactured in this embodiment is shown below.

Outer diameter of integrated actuator 20: 40 × 40 × 1 mm Number of cantilevers: 90 Length of each cantilever: 500 μm Width of each cantilever: 50 μm Height of probe 123: 3 μm Example 8 Implemented in FIG. 9 is a schematic diagram of an information processing apparatus capable of recording / reproducing information using the integrated actuator described in Example 7. FIG.

In the figure, 233 is a recording layer whose resistance value changes by voltage application, 232 is a metal electrode layer, and 231 is a recording medium substrate. 234 is an XY stage, 235 is an integrated actuator according to the present invention, 236 is a support for the integrated actuator, 237 is a linear actuator for coarsely moving the integrated actuator in the Z direction, 23
Reference numerals 8 and 239 are linear actuators for driving the XY stage in the X and Y directions, respectively, and 240 is a bias circuit for recording and reproduction. 241 is a tunnel current detector, 242
Is a servo circuit for moving the integrated actuator in the Z-axis direction, and 243 is a servo circuit for driving the actuator 237. 244 is a drive circuit for minutely displacing each cantilever, and 245
Is a drive circuit for controlling the position of the XY stage. 24
A computer 6 controls these operations.

By using such a system,
It is possible to record a large amount of information at a high density, and since a large number of probes are integrated and they are simultaneously scanned, high-speed recording / reproducing can be performed.

By providing the vibration absorbing electrode according to the present invention in such a system, the resolution of each probe is improved, the tracking performance during recording / reproducing is improved, and the error occurrence rate during writing / reading is reduced. can do.

[0081]

As described above, according to the driving method of the cantilever type displacement element of the present invention, the responsiveness is good, the accurate positioning can be performed, and there is no unnecessary vibration. A processing device can be realized.

Further, according to the cantilever type displacement element of the present invention, the damaging vibration of the harmful vibration generated in the cantilever portion is significantly accelerated, thereby improving the positioning accuracy and enabling the high speed control. Further, in the STM device using the cantilever type displacement element of the present invention, the resolution is improved, and in the information processing device, further higher density,
The speed can be increased and the error occurrence rate can be reduced.

[Brief description of drawings]

FIG. 1 is a diagram showing a cantilever type displacement element according to the present invention.

FIG. 2 is a diagram showing a manufacturing process of the cantilever type displacement element shown in FIG.

FIG. 3 is a schematic connection diagram of a cantilever type displacement element according to the present invention.

FIG. 4 is a diagram showing displacement characteristics of a cantilever type displacement element according to the present invention.

FIG. 5 is a diagram showing displacement characteristics of a cantilever type displacement element according to the present invention.

FIG. 6 is a diagram showing an STM device of the present invention.

FIG. 7 is a diagram showing an information processing device of the present invention.

FIG. 8 is a diagram showing a voltage applied to a recording medium.

FIG. 9 is a view showing a conventional cantilever type displacement element.

FIG. 10 is a view showing a conventional cantilever type displacement element.

FIG. 11 is a configuration diagram of a cantilever type displacement element according to a fourth embodiment.

FIG. 12 is a diagram showing displacement characteristics of a cantilever displacement element of Example 4 and a conventional example.

FIG. 13 is a manufacturing process diagram of the cantilever displacement element of Example 4;

FIG. 14 is a configuration diagram of a cantilever type displacement element according to a fifth embodiment.

FIG. 15 is another configuration diagram of the fifth embodiment.

FIG. 16 is another configuration diagram of the fifth embodiment.

FIG. 17 is another configuration diagram of the fifth embodiment.

FIG. 18 is another configuration diagram of the fifth embodiment.

FIG. 19 is a configuration diagram of a cantilever type displacement element of Example 6;

FIG. 20 is a configuration diagram of a cantilever displacement element according to a sixth embodiment.

FIG. 21 is a configuration diagram of an integrated actuator of Example 7.

FIG. 22 is a diagram illustrating an S using the integrated actuator of Example 7.
It is a fragmentary sectional view of TM.

FIG. 23 is a block configuration diagram of an information processing apparatus using an integrated actuator of Example 8.

FIG. 24 is a configuration diagram of a conventional cantilever displacement element.

[Explanation of symbols]

 1,1 ′ Silicon substrate 2,3 Silicon nitride film 4,8 Piezoelectric thin film 5,6,9 Electrode 10 STM probe 11 Electrostatic drive electrode 12 Substrate 13 Thermal oxide film 14 Silicon nitride film 15 Parallel plate capacitor part 16 Static Variable power DC power supply 17 Current-voltage conversion amplifier 18 Signal output 19 Piezoelectric body driving power supply 61 Vibration isolation table 62 XY scanning mechanism 63 Sample 64 Z coarse movement mechanism 65 Cantilever type displacement element 66 STM probe 67 XY driving circuit 68 Bias applying circuit 69 Tunnel Current detection circuit 70 Z drive circuit 71 Electrostatic force applied voltage circuit 72 Piezoelectric drive circuit 73 Microcomputer 74 Display device 75 Recording medium 76 Multi cantilever type displacement element 77 Cantilever 91 Cantilever type displacement element 92 Support body 93 Free end portion 94 Al 95 ZnO 11 Substrate 112, 112a, 112b Lower electrode 113a Lower piezoelectric thin film 113b Upper piezoelectric thin film 114 Intermediate electrode 115, 115a, 115b Upper electrode 116a-d Vibration absorption electrode 118 Cantilever part 119 Insulating layer 120 Through hole 121 Side electrode 122 Extraction electrode 123 Probe 211 Integrated actuator 221,223 Movable stage 222 Sample 231 Recording medium substrate 232 Metal electrode layer 233 Recording layer 234 XY stage 235 Integrated actuator 236 Support 237 Z direction linear actuator 238 X direction linear actuator 239 Y direction linear actuator 240 recording / reproducing bias circuit 241 tunnel current detector 242, 243 servo circuit 244, 245 drive circuit 246 computer

 ─────────────────────────────────────────────────── ─── Continued front page (72) Inventor Yu Nakayama 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (72) Inventor Haruki Kawada 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Within the corporation

Claims (10)

[Claims] 1. A cantilever type displacement element comprising at least one layer of a piezoelectric body for changing the cross-sectional shape of a surface of the cantilever orthogonal to the longitudinal direction, and an electrode for applying a voltage to the piezoelectric body. An electrostatic drive electrode is provided in parallel with the electrode, a parallel plate capacitor is formed with the piezoelectric body drive electrode, and the vibration of the displacement element is controlled by applying a voltage to the parallel plate capacitor. Driving method of cantilever type displacement element. 2. A scanning tunneling microscope using the driving method of a cantilever type displacement element according to claim 1. 3. An information processing apparatus using the driving method of a cantilever type displacement element according to claim 1. 4. A cantilever type displacement element comprising a piezoelectric body and an electrode for applying a voltage to the piezoelectric body laminated, wherein the piezoelectric body driving electrode is insulated from the upper and lower surfaces of the piezoelectric body. And a pair of upper and lower vibration absorbing electrodes are electrically connected to each other, and a cantilever type displacement element. 5. The cantilever according to claim 4, wherein the vibration absorbing electrodes are provided on both sides of the piezoelectric body driving electrode with the piezoelectric body driving electrode interposed therebetween, and the vibration absorbing electrodes on both sides are electrically connected. Mold displacement element. 6. The cantilever type displacement element according to claim 4, wherein the piezoelectric body is made of a zinc oxide thin film. 7. The cantilever type displacement element according to claim 4, wherein a conductive probe and an extraction electrode are provided at the tip of the cantilever portion. 8. A cantilever type displacement element comprising a plurality of the cantilever type displacement elements according to claim 4 arranged on the same silicon single crystal substrate. 9. A scanning tunneling microscope using the cantilever type displacement element according to claim 4. 10. An information processing apparatus for recording / reproducing information on / from a recording medium by using a tunnel current.
9. An information processing device comprising the cantilever type displacement element according to any one of items 8 to 8.