JP3060142B2 - Driving method of cantilever type displacement element, scanning tunneling microscope, information processing apparatus, and cantilever type displacement element - Google Patents

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 A cantilever type displacement element of this type is conventionally known as shown in FIG.

The cantilever type displacement element 91 used here has a laminated structure formed by piezoelectric thin films 4, 8 formed of electrically polarized PZT or the like and electrodes 5, 6, 9. I have. This cantilever type displacement element is fixed by a support 92 to be a cantilever type. When a voltage is applied to the electrodes 5, 6, and 9 in the contracting direction, the extending direction, or the opposite direction, the piezoelectric thin films 4, 8 are displaced upward or downward. Due to this bending displacement, the free end portion 93 can be displaced in the vertical direction.

In recent years, with the background of semiconductor process technology, mechanical electric elements (micromechanics) such as a semiconductor pressure sensor, a semiconductor acceleration sensor, and a microactuator using a semiconductor as a mechanical structure have come into the spotlight. Was.

[0005] The features of such an element include that a small and high-precision mechanical mechanism part can be provided, and the element and an electric circuit can be integrated on a Si wafer because a semiconductor wafer is used. Further, by manufacturing based on a semiconductor process, improvement in productivity by batch processing of the semiconductor process can be expected. In particular, a cantilever-type displacement element using a piezoelectric thin film can be mentioned, and since it can control very fine movement, it is applied to an STM that can directly observe an atomic level and a molecular level. For example, an STM probe using a cantilever type displacement element proposed by Kuwait of Stanford University (IEEE)
E Micro Electro Mechanical
al Systems, p188-199, Feb. 1
990). As shown in FIG. 10, a silicon substrate is formed by partially removing the back surface of the wafer of the Si substrate (wafer) 1, a thin film of Al94 and ZnO95 is sequentially laminated on the front surface, and a bimorph cantilever is formed.
The silicon membrane and the protective layer (silicon nitride film) for etching the surface of the wafer are removed from the back surface by reactive dry etching to produce a bimorph cantilever displacement element for displacing the STM probe. The tunnel current detecting probe 10 is attached to the free end of the upper surface of this cantilever, and a good STM image is obtained.

On the other hand, by using the STM technique, observation and evaluation of atomic order and molecular order of a semiconductor or a polymer material, and fine processing (EE Ehrichs, 4th In).
international Conference on
Scanning Tunneling Micro
scopy / Spectroscopy, '89, S1
3-3) and applications of the recording / reproducing apparatus to various fields are being studied. Above all, there is an increasing demand for large-capacity recording devices for computer calculation information, etc., and with advances in semiconductor process technology, microprocessors have been downsized and computational capabilities have been 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 probe for generating a tunnel current, which is located on a driving means whose distance to the recording medium can be finely adjusted. An information processing apparatus has been proposed in which information is read out by writing and detecting a change in a tunnel current due to a change in shape, and the minimum recording area is 10 nm square (US Pat. No. 4,575,822).

[0007] The STM utilizes a tunnel effect in which a current flows through a barrier between the sharp conductive probe and a sample surface when the probe approaches a sample surface of several nm or less. [G. Binnig et al. , Helvet
ica Physica Acta, 55, 726 (1
982), U.S. Pat. No. 4,343,993].

An apparatus for performing high-density information processing (recording / reproducing) by applying the principle of the STM is disclosed in JP-A-63-161.
552, and Japanese Patent Application Laid-Open No. 63-161553. In this method, recording is performed by using a probe similar to the STM and changing the voltage applied between the probe and the recording medium.

Conventionally, as a method of forming a probe used in these recording / reproducing apparatuses, a processing technique for forming a fine structure on one substrate using a semiconductor manufacturing process technique [K. E. FIG. Peterson "Silicon as
a MechanicMaterial ", Pr
received of the IEEE, 70
(5), 420-457 (1982)]. The STM constructed by such a method is disclosed in
It has been proposed in Japanese Patent Application Laid-Open No. 1-206148.

[0010] This is to form a parallel spring that can be finely moved in the X and Y directions by fine processing using single crystal silicon as a substrate,
Further, a cantilever portion having a probe formed on the movable portion is provided, and an electric field is applied to the cantilever portion and the bottom portion so as to be displaced by electrostatic force in a direction Z perpendicular to the plane of the substrate.

[0011]

The conventional cantilever-type displacement element has no means for restricting particularly the displacement amount and the operating force of the displacement element. In particular, when a cantilever type displacement element is used as an STM probe, the displacement amount and the operating force become very important. The STM is to observe the unevenness of the sample by bringing the tip of the needle close to the sample up to several square meters and monitoring the tunnel current flowing therebetween. For this reason, it is desirable that the STM probe be minutely displaced at high speed and with high accuracy. For this reason, the conventional cantilever-type displacement element does not have a means for regulating and controlling the displacement amount and the operating force, and the characteristic of the cantilever-type displacement element is uniquely determined. It was difficult to control.

In an information processing apparatus to which STM is applied, information on a recording medium is converted into bits formed by physical changes such as bits due to irregularities on the recording medium by applying an electric pulse from an 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 an information processing apparatus using such a method, an STM probe attached to a free end of a cantilever-type displacement element applies various time-varying applied voltages to a piezoelectric body in order to perform positioning with respect to a recording medium. Must give. For example, when a rectangular wave voltage is applied, the cantilever-type displacement element responds with a rectangular wave and generates unnecessary vibration whose main component is a natural frequency.
Until the unnecessary vibration is attenuated, the next operation cannot be performed, so that the speeding up of the information processing apparatus has been suppressed. Unnecessary vibrations need to be removed or attenuated as much as possible. For this reason, it is customary to sandwich the support portion of the cantilever with rubber or the like having a damper effect. However, in a cantilever type displacement element manufactured by a thin film technique and an etching technique by a semiconductor process, such an attempt is difficult due to its configuration.

[0013]

The objects of the present invention are as follows: (1) It has a high-speed and accurate displacement amount.

(2) Unnecessary vibrations are eliminated to increase the speed.

The above is the object of the present invention. 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 is to change the cantilever .
A piezoelectric two layers for causing position, a piezoelectric driving electrode for applying a voltage to the piezoelectric body, the cantilever type displacement element provided with the, for parallel electrostatic drive and the piezoelectric driving electrodes Providing an electrode, forming a parallel plate capacitor with the electrostatic drive electrode and the piezoelectric body drive electrode, and controlling the vibration of the displacement element by applying a voltage to the parallel plate capacitor. The second is a method for driving the mold displacement element.
M is an information processing device using the above driving method.

According to this configuration, 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 precisely control a desired minute displacement amount. Further, as a result of suppressing the generated force by the electrostatic force, it works as a damper effect, and unnecessary vibration can be removed.

A fourth aspect of the present invention is a cantilever-type displacement element comprising a piezoelectric body and an electrode for applying a voltage to the piezoelectric body, wherein the piezoelectric body has upper and lower piezoelectric driving elements. The cantilever-type displacement element is characterized in that the vibration-absorbing electrode is provided in an insulated state, and a pair of upper and lower vibration-absorbing electrodes are electrically connected to each other. A sixth is an STM using the fourth cantilever type displacement element, and a seventh is an information processing apparatus.

According to the above configuration, the electric charge generated on the surface by 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 the elastic vibration is converted into electric energy, and finally becomes Joule heat. For this reason, it is possible to greatly reduce the vibration damping time.

Further, by providing the above-mentioned pair of upper and lower vibration absorbing electrodes on the left and right sides of the cantilever portion and electrically connecting them, 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. High-speed, high-precision displacement control was possible because of absorption. In addition, by removing such harmful vibrations, a high-precision and high-speed STM probe can be realized.

Further, by integrating a plurality of components on the same substrate,
A small and high-accuracy STM system having a multi-probe can be constructed, and semiconductor elements such as transistors and diodes can be simultaneously integrated by using a Si single crystal as a substrate.

Further, it has become possible to provide an information processing apparatus capable of performing large-capacity, high-density recording and reproduction using a medium whose state changes by applying a voltage as an STM observation object.

[0023]

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

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

FIG. 1A is a perspective view of a cantilever type displacement element according to this embodiment. This is manufactured on a Si substrate by a normal IC manufacturing process and anisotropic etching of Si. FIG. 1B is a schematic view of a cross-sectional view of a cantilever type displacement element. Electrode 5 on Si substrate 12,
It is composed of a bimorph cantilever-type displacement element having a piezoelectric thin film 4, an electrode 6, a piezoelectric thin film 8, and an electrode 9 stacked in this order, and an electrostatic drive electrode 11 attached to the lower side of the back of the cantilever on a Si substrate. You. The electrode 5 and the electrode 1
1 forms a parallel plate capacitor. Reference numeral 10 denotes a tunnel current detection probe.

FIG. 2 is a view showing a manufacturing process of the above-mentioned cantilever type displacement element. First, the cantilever portion will be described (FIGS. 2A to 2D). First, a 250 μm thick Si
(100) The silicon nitride films 2 and 3 are stacked on the substrate 1 by LP-CVD at 500.degree. And patterned by photolithography to form an etching mask. Next, the Au electrode 5 was laminated by 1000 ° by a resistance heating method and patterned. Further, the piezoelectric ZnO thin film 4 is 1 μm thick by RF magnetron sputtering, and Au is formed by resistance heating.
The electrode 6 is set to 1000 ° and the piezoelectric ZnO is again
The thin film 8 was laminated at 1 μm and patterned.
(A)). Subsequently, an Au lead electrode 9 was deposited at a thickness of 1000 ° by a resistance heating method, and patterning was performed. On the upper part, an STM probe 10 for detecting a tunnel current formed of Pt by a vapor deposition method was manufactured (FIG. 2B).
Thereafter, anisotropic etching of Si was performed using a KOH solution to produce a cantilever (FIG. 2C). Finally,
The silicon nitride film was removed by a reactive ion etching method (FIG. 2D).

Next, the parallel plate condenser side will be described (FIGS. 2E to 2H). First, thickness 250μm
A thermal oxide film 13 of Si was formed on the Si (100) substrate 1 'of FIG. Next, LP-
The silicon nitride film 14 was laminated by 2000 ° by CVD and patterned to form an etching mask (FIG. 2).
(F)). Then, the Au electrode 11 is set to 1 by a resistance heating method.
000 was laminated and patterned (FIG. 2 (g)). Furthermore, anisotropic etching of Si is performed with a KOH solution,
A trapezoidal base 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 substrate (FIG. 2 (h)) were adhered by anodic bonding to form a parallel plate capacitor portion 15 (FIG. 2 (i)).

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

At this time, the displacement characteristics of the cantilever type displacement element when no applied voltage was applied to the parallel plate capacitor portion were as follows.

Natural frequency 20 KHz Displacement amount 0.25 μm / V (Displacement amount of free end with respect to piezoelectric unit applied voltage) Mechanical Q value at natural vibration 56 Next, a driving method of the cantilever type 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 power supply 19 is connected to the middle electrode 6. The middle electrode 6 is grounded. Next, the variable electrostatic direct-current power supply 16 of the parallel plate condenser section is connected as shown in FIG. Reference numeral 17 denotes a current-voltage conversion amplifier, and reference numeral 18 denotes a signal output of a tunnel current. By setting the variable DC power supply 16 to an appropriate voltage, the amount of displacement and 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 driving voltage of the piezoelectric body and the amount of displacement of the free end of the free end of the cantilever by various electrostatic force applied voltages. It can be seen that the inclination of the displacement amount of the cantilever changes according to the applied electrostatic force voltage, and the displacement amount per unit applied voltage of the piezoelectric body can be controlled by the applied electrostatic force voltage. The difference in the intercept for the displacement of the cantilever is that
This is because the cantilever part is slightly curved by the electrostatic force. By providing the parallel plate capacitor in this manner, the inclination of the displacement amount in the voltage applied to the piezoelectric body can be changed, so that various minute displacement amounts can be controlled, and positioning can be performed accurately.

FIG. 5 (a) shows the frequency response of various electrostatic force applied voltages when a sine-wave applied piezoelectric body voltage is applied while the piezoelectric body applied voltage value is fixed. The frequency response at this time was as follows.

Electrostatic force applied voltage 0 V Natural frequency 20 KHz Mechanical Q value 56 Static force applied voltage 10 V Natural frequency 25 kHz Mechanical Q value 6 By changing the electrostatic force applied voltage in this way, the natural frequency is increased. The target Q value could be reduced.

FIG. 5 (b) shows a rectangular wave (1
(msec) is shown, the response of the displacement amount at the time of various electrostatic force application voltages is observed. 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, the electrostatic force applied voltage 1
At 0 V, no unnecessary vibration is seen at all, and it can be seen that a high-speed response is possible.

As described above, a cantilever-type displacement element having a high-speed response, a high-precision displacement, and no unnecessary vibration can be formed. If desired responsiveness and displacement are required, designs such as changing the length of the cantilever type displacement element, changing the material of the piezoelectric thin film, changing the thickness, etc. may be performed. 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.

Embodiment 2 An STM apparatus using the cantilever type displacement element of Embodiment 1 will be described. FIG. 6 shows a configuration diagram of the STM of this embodiment. An XY scanning mechanism 62 is installed on the vibration isolation 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 formed at the tip of the cantilever. The XY scanning mechanism 62 is driven by an XY drive circuit 67, and the Z coarse movement mechanism 64 is driven by a Z drive circuit 70. The displacement characteristics of the cantilever 65 can be varied by an electrostatic force application voltage circuit 71. Feedback is applied in the Z direction by the piezoelectric drive (feedback) circuit 72 so that the tunnel current 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 application circuit 68 and detected by the tunnel current detection circuit 69. All the circuits are controlled in a unified manner by a microcomputer 73, and the observation results are displayed on a display device 74.

In this embodiment, an Au thin film epitaxially grown was used for the sample. At this time, 1 μm × 1
STM observation of the region of μm was performed. First, S is applied by the electrostatic force application voltage circuit 71 at 0 V and in the 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 a scanning speed of 200 Hz in the X direction. According to the present method, an STM in which a clear image can be obtained at high speed
Is obtained.

Embodiment 3 In this embodiment, an information processing apparatus using the cantilever type displacement element of Embodiment 1 will be described. FIG. 7 is a configuration diagram of the information processing apparatus of the present embodiment. X on seismic isolation table 61
A Y scanning mechanism 62 is provided, and a recording medium 75 is further provided thereon. The XY scanning mechanism 62 is driven by an XY driving circuit 67, and various biases or pulse voltages for writing, reading, and erasing of 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-type displacement elements 76 are installed on 4, and 4 × 3 = 12 cantilevers 77 are attached. 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 a tunnel current detection circuit 69, and each cantilever is driven by a piezoelectric drive (feedback) circuit 72. Further, the displacement characteristics can be controlled by the electrostatic force application voltage circuit 71. All circuits are controlled by the microcomputer 73. The recording medium 75 is an Au thin film (2500 °) epitaxially grown on a mica substrate.
A layer having an organic recording layer laminated thereon was used. As the organic recording layer, an LB film (one layer) of squarylium-bis-6-octiazulene was used. The method of forming the LB film is as follows.
The method disclosed in JP-A-63-161552 was followed.

Next, a recording / reproducing method will be described. First, one of the STM probes is set to the + side and the Au thin film is set to the − side, and a pulse voltage (shown in FIG. 8) that is higher than the threshold voltage V _th ON at which the recording layer changes to a low resistance state (ON state) is applied. Then, an ON state was generated. While maintaining the distance between the STM probe and the recording layer, the distance between the probe and the Au thin film is 1 mm.
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 was in an ON state.

Next, recording was performed one after another using this information processing apparatus. First, the electrostatic force applied voltage was set to 0 V, and 12 cantilevers were sequentially driven at a speed of 10 msec per bit for each cantilever to perform recording. Thereafter, it was possible to read this information at the same speed. At this time, no recording bit error was observed. Next, a similar experiment was performed at a speed of 5 msec per bit, and after that, when reproduction was performed, an error of about 1% was detected in the recording bit. However, when the same experiment was performed with the applied electrostatic force voltage set to 5 V, 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. 11B is a cross-sectional view taken along the line AA 'in FIG. 11A.

In this figure, reference numeral 111 denotes a substrate;
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 with their polarization axes 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, and 115 are drawn out to the outside, so that a driving voltage can be applied from the outside.

Electrodes 116a and 116d for vibration absorption and 1
16b and 116c are electrically connected on the substrate 111. With such a structure, the cantilever portion 1
Unnecessary vibrations generated when the actuator 18 is displaced can be electrically absorbed.

Hereinafter, the principle will be described. Electrodes 112,
When a predetermined voltage is applied to 114 and 115 and the cantilever portion 118 is bent and displaced, the cantilever portion 118 vibrates up and down around a target displacement amount. The situation at this time is shown in FIG. This vibration deforms the piezoelectric thin films 113a and 113b,
Electric charges are generated on the surfaces of 13a and 113b by the piezoelectric effect. At this time, the lower surface of the piezoelectric thin film 113a and 11
Since the compression deformation and the expansion deformation alternately occur on the surface above 3b, the sign of the generated charge is always opposite.

The vibration absorbing electrode 116 according to the present invention
a, 116b, 116c, and 116d are converted to the piezoelectric thin film 113.
a, 113b, and electrically connect the upper and lower parts 116a and 116d and the parts 116b and 116c which are opposed to each other with the piezoelectric body interposed therebetween. As a result, the electric charge generated by the piezoelectric effect is reduced to the vibration absorbing electrodes 116a and 116d and 116b and 1b.
The current reciprocates between 16c as a current. Therefore, a part of the energy of the vibration is converted into electric energy, so that the attenuation of the vibration can be accelerated.

The electrodes 116a, 1 for absorbing vibration according to the present invention
FIG. 12B shows the displacement characteristics of the cantilever portion 118 provided with 16b, 116c, and 116d.

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 the present embodiment will be described with reference to FIGS.

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

Next, ZnO was deposited thereon by sputtering deposition.
Is formed to form a piezoelectric thin film 113a.
At this time, by appropriately adjusting the conditions of the sputter deposition, the piezoelectric polarization axis (C axis) and the polarity thereof can be aligned (FIG. 13B).

Next, Au is deposited again on the piezoelectric thin film 113a by a vacuum evaporation method at a thickness of 1000 °. Thereafter, 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 is formed (FIG. 13D).

A film of Au is again formed to a thickness of 1000 ° and patterned by photolithography to form the upper electrode 115 and the electrodes 116a and 116b for vibration absorption. Thereafter, photolithography is performed again to remove unnecessary portions of ZnO by etching (FIG. 13E).

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

The etching solution used in the photolithography is a KI: I ₂ aqueous solution for Au, an (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 Si anisotropic etching, and CF ₄ gas was used for reactive ion etching.

The following is an example of the dimensions and drive characteristics of each part of the cantilever type displacement element manufactured in this embodiment.

The length of the cantilever 118 is 500 μm and the width is 50 μm. The voltage applied to the lower electrode 112 and the upper electrode 115 is ± 3 V with the intermediate electrode 114 serving as the ground.
μm Unnecessary vibration decay time 10 msec By using the present invention as described above, the decay time of unnecessary vibration generated in the cantilever-type displacement element can be greatly reduced, and the accuracy in position control can be greatly improved.

In this embodiment, ZnO is used as the piezoelectric body, but this is not limited to ZnO.
1N, PZT, BaTiO ₃ , LiNbO ₃ , PVDF
The same effect can be obtained by using other piezoelectric materials. Although Au and Cr are used as electrode materials, Pt, Pd,
The same effect can be obtained by substituting another conductive substance such as Ti, W, or Al.

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

Embodiment 5 FIG. 14 shows a fifth embodiment of the present invention. FIG. 14B is a cross-sectional view taken along the plane BB ′ in FIG. In this embodiment, the cantilever-type displacement element having a structure in which the lower electrode is divided into two, that is, 112a and 112b and the upper electrode is divided into 115a and 115b.
This is a displacement element capable of performing minute displacement in the horizontal direction in addition to bending displacement in the vertical direction according to the fourth embodiment by reversing the negative sign of the voltage applied to 112b and 115b.

In this embodiment, the vibration absorbing electrode 116 is used.
a, 116b, 116c, and 116d are 116a and 11
In addition to the electrical connection between 6d and 116b and 116c, 116a and 116b and 116c and 116d are further 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 and the vibration in the diagonal direction of the cantilever portion 118 are electrically controlled. It becomes possible to absorb it.

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 described in the fourth embodiment.

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

Further, as shown in FIG.
The same effect can be obtained even if the side surface electrode 121 is formed on part or all of the side surface of the 18.

When only the ground is applied to the intermediate electrode, the structure is such that the intermediate electrode 114 is connected to the intermediate electrode 114 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. It is also possible to have a structure that does this. With such a structure, electric charges generated on the surface due to the piezoelectric effect can be more effectively consumed as current, and the efficiency of vibration absorption increases.

Embodiment 6 FIGS. 19 and 20 show a sixth embodiment of the present invention. FIG.
19B is a sectional view taken along the line CC ′ in FIG. 19A, and FIG. 20 is a rear view of FIG.

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

By providing the conductive probe 123 at the tip as described above, the cantilever-type displacement element according to the present invention can be used as an STM probe. That is, a predetermined drive voltage is applied to each electrode, and the cantilever portion 118
Is bent and displaced so that the probe 123 approaches 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 the tunnel current changes exponentially depending on the distance between the tip and the surface of the probe 23, the tunnel current is extracted through the extraction electrode 122, amplified, and the drive voltage of the cantilever portion 118 is fed back. The distance to the surface can be kept constant. By slightly moving the cantilever portion in the x and y directions in such a state, it is possible to observe the unevenness of the very minute surface, the distribution of electric resistance, and the like from the change in the feedback voltage. The vibration absorbing electrodes 116a, 116b,
The provision of 116c and 116d can suppress generation of harmful vibrations, and can provide accurate feedback, so that the resolution of the STM can be increased.

Such a probe can be manufactured by changing the pattern of a photolithographic photomask in the manufacturing method described in the fourth embodiment. After forming the upper electrode, the conductive probe 123 may
The resist was removed only at the position where the probe 123 was to be formed by applying μm, and the resist was formed by a method combining vapor deposition from oblique directions 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-type actuators having the probe 123 described in the sixth embodiment are manufactured on the same silicon substrate 111, and an integrated actuator 211 is manufactured.

In such an integrated actuator, in the manufacturing method described in the fourth and fifth embodiments, it is only necessary to extend the photolithographic pattern. In this way, since 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 very small.

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

FIG. 21 is a diagram schematically showing an STM device using the integrated actuator of this embodiment. Thereby, the sample 222 is used by using the integrated actuator 211.
STM images of a plurality of minute regions on the surface of the device can be observed at the same time. In the figure, 221 and 223 are x,
a movable stage having a coarse movement mechanism in the y and z directions,
An integrated actuator 211 is fixed to the movable stage 221, and a sample 222 is fixed to the movable stage 223.

The following is an example of the dimensions of the integrated actuator manufactured in this embodiment.

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 FIG. FIG. 14 shows a schematic diagram of an information processing apparatus capable of recording and reproducing information using the integrated actuator described in Example 7.

In the figure, reference numeral 233 denotes a recording layer whose resistance value changes by applying a voltage, 232 denotes a metal electrode layer, and 231 denotes a recording medium substrate. 234, an XY stage; 235, an integrated actuator according to the present invention; 236, a support for the integrated actuator; 237, a linear actuator for coarsely moving the integrated actuator in the Z direction;
8, 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
Reference numeral 243 denotes a servo circuit for moving the integrated actuator in the Z-axis direction, and reference numeral 243 denotes a servo circuit for driving the actuator 237. Reference numeral 244 denotes a drive circuit for minutely displacing each cantilever.
Is a drive circuit for controlling the position of the XY stage. 24
A computer 6 controls these operations.

By using such a system,
Since a large amount of information can be recorded at a high density, and a large number of probes are integrated and scanned simultaneously, high-speed recording and reproduction 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 at the time of recording and reproduction is improved, and the error rate at the time of writing and 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 response is good, the positioning can be performed with high accuracy, and there is no unnecessary vibration. A processing device can be realized.

According to the cantilever type displacement element of the present invention, the harmful vibration generated in the cantilever portion is greatly attenuated, whereby the positioning accuracy is improved and high-speed control is possible. 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, the density is further increased.
It is possible to increase the speed and reduce the error occurrence rate.

[Brief description of the drawings]

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

FIG. 2 is a view 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 view showing a displacement characteristic of the cantilever displacement element according to the present invention.

FIG. 5 is a view showing displacement characteristics of the 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 apparatus of the present invention.

FIG. 8 is a diagram illustrating 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 displacement element according to a fourth embodiment.

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

FIG. 13 is a manufacturing process diagram of the cantilever-type displacement element of the fourth embodiment.

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

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 according to a seventh embodiment.

FIG. 22 shows an example of S using the integrated actuator of the seventh embodiment.
It is a fragmentary sectional view of TM.

FIG. 23 is a block diagram of an information processing apparatus using an integrated actuator according to an eighth embodiment.

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

[Explanation of symbols]

 DESCRIPTION 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 Power supply for driving piezoelectric body 61 Isolation table 62 XY scanning mechanism 63 Sample 64 Z coarse movement mechanism 65 Cantilever type displacement element 66 STM probe 67 XY drive circuit 68 Bias application circuit 69 Tunnel Current detection circuit 70 Z drive circuit 71 Electrostatic force application 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 93 Free end 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 absorbing electrode 118 Cantilever portion 119 Insulating layer 120 Through hole 121 Side electrode 122 Extraction electrode 123 Probe 211 Integrated actuator 221 and 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 bias circuit for recording / reproduction 241 tunnel current detector 242,243 servo circuit 244,245 drive circuit 246 computer

Continued on the front page (72) Inventor: Yu Nakayama 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (72) Inventor Haruki: 3-30-2 Shimomaruko, Ota-ku, Tokyo Canon Inc. (56) References JP-A-4-320918 (JP, A) JP-A-2-123541 (JP, A) JP-A-4-206536 (JP, A) JP-A-54-100687 (JP, A) JP-A-57-155000 (JP, A) JP-A-60-62170 (JP, A) JP-A-2-119278 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) G11B 9 / 14 G01N 13/12 G12B 21/20 H01L 41/09

Claims (10)

(57) [Claims] And <br/> piezoelectric body 2 layer for displacing the 1. A cantilever, a piezoelectric driving electrode for applying a voltage to the piezoelectric body, the cantilever type displacement element provided with the above piezoelectric An electrostatic drive electrode is provided in parallel with the body drive electrode, a parallel plate capacitor is formed by the electrostatic drive electrode and the piezoelectric body drive electrode, and a voltage is applied to the parallel plate capacitor to thereby displace the displacement element. A method for driving a cantilever-type displacement element, characterized by controlling vibration of a cantilever. 2. A scanning tunneling microscope using the method for driving a cantilever type displacement element according to claim 1. 3. An information processing apparatus using the method for driving 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, wherein the upper and lower surfaces of the piezoelectric body are insulated from electrodes for driving the piezoelectric body. And a pair of upper and lower vibration absorbing electrodes are electrically connected to each other. 5. The cantilever according to claim 4, wherein the vibration absorbing electrodes are provided on both sides of the piezoelectric body driving electrode, and the vibration absorbing electrodes on both sides are electrically connected. Type 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 a tip of the cantilever portion. 8. A cantilever-type displacement element according to claim 4, wherein a plurality of cantilever-type displacement elements according to claim 4 are arranged on the same silicon single crystal substrate. 9. A scanning tunneling microscope using the cantilever-type displacement element according to claim 4. Description: 10. An information processing apparatus for recording / reproducing information on / from a recording medium using a tunnel current.
An information processing apparatus using the cantilever-type displacement element according to any one of claims 1 to 8.