JP5052835B2 - Piezoelectric actuator and manufacturing method thereof - Google Patents

Description

  The present invention relates to a piezoelectric actuator using a piezoelectric material and a manufacturing method thereof.

  2. Description of the Related Art Conventionally, as an example of an apparatus that deflects and scans a light beam such as a laser beam, a device that rotates and vibrates a plane mirror for polarization with an electromagnetic actuator has been used. However, in an electromagnetic actuator, since it is necessary to arrange a permanent magnet outside, the configuration of the device is complicated and it is difficult to reduce the size. In addition, since the magnetic field is generated by driving the electromagnetic actuator, there is a possibility of adversely affecting other nearby devices.

On the other hand, a piezoelectric actuator using a thin film piezoelectric body made of a thin film piezoelectric material as an actuator has been proposed (see, for example, Patent Document 1). In this piezoelectric actuator, in order to efficiently convert a minute generated force of the thin film piezoelectric body into a mechanical motion, the thin film piezoelectric body is superposed on the cantilever. This structure is called a unimorph cantilever structure, and in-plane expansion / contraction resulting from the piezoelectric characteristics of the piezoelectric material is transmitted to the support bonded below, causing the tip portion to vibrate up and down. Therefore, when the piezoelectric cantilever is used as an actuator, the device is driven by transmitting a generated force or displacement by mechanically connecting a movable part or the like to its tip. Such a device can be formed by being integrally processed by a so-called semiconductor planar process and a micro electro mechanical systems (MEMS) process, and can be miniaturized and easily manufactured.
JP 2005-148459 A

  In the piezoelectric actuator disclosed in Patent Document 1, the magnitude of torque and displacement generated at the tip is determined by the generated force generated from the piezoelectric body and the size of the cantilever. For this reason, in order to obtain a large torque or displacement, it is necessary to increase the size, particularly the length, of the cantilever. Accordingly, in a device that requires a large torque or displacement, the size of the actuator increases, and the entire device increases in size. However, when the device increases in size, for example, the number of device chips that can be manufactured per unit wafer decreases. Also, an increase in the size of the cantilever reduces the rigidity of the structure, so that its operation is likely to be affected by disturbances or may be weak against impact. Furthermore, as the size of the cantilever increases, the influence of torque or displacement attenuation (air damping) due to the viscous resistance of air increases.

  Moreover, in the said patent document 1, the piezoelectric actuator which has only a single cantilever is arrange | positioned elastically connected. Since a single cantilever has its supported end as a fulcrum and its tip vibrates in one direction, the displacement of this piezoelectric actuator is only in one direction. For this reason, it is difficult to mount on a device that requires a complicated operation such as displacement in two or more directions.

  In view of the above circumstances, an object of the present invention is to provide a piezoelectric actuator that is small in size and capable of obtaining an extended torque or displacement, and a manufacturing method thereof.

The piezoelectric actuator of the present invention includes a support body and a plurality of piezoelectric cantilevers that have a piezoelectric body formed on the support body and bend and deform by piezoelectric driving, and drive voltages are respectively applied to the piezoelectric bodies of the plurality of piezoelectric cantilevers. Independently equipped with multiple electrodes to apply,
The ends of the plurality of piezoelectric cantilevers are mechanically coupled so as to accumulate each bending deformation, and each piezoelectric cantilever is independently bent and deformed by application of the driving voltage ,
The plurality of piezoelectric cantilever supports are integrally formed by processing a semiconductor substrate,
The piezoelectric bodies of the plurality of piezoelectric cantilevers are formed by processing a single-layer piezoelectric film directly formed on the semiconductor substrate,
The electrode includes a lower electrode formed by processing a lower electrode layer, which is a metal thin film directly formed between a semiconductor substrate and a single-layer piezoelectric film formed on the semiconductor substrate, and a piezoelectric film An upper electrode formed by processing the upper electrode layer, which is a metal thin film directly formed thereon, and the upper electrode layer and the piezoelectric film of the upper electrode layer and the piezoelectric film are partially processed to form the upper electrode layer and the piezoelectric body. And an electrode wiring pattern for applying a driving voltage to a piezoelectric body of a predetermined piezoelectric cantilever among the plurality of piezoelectric cantilevers formed separately .

  According to the piezoelectric actuator of the present invention, each of the plurality of piezoelectric cantilevers is bent and deformed by piezoelectric driving, and the other end portion (distal end portion) with one end portion (base end portion) of each piezoelectric cantilever as a support shaft. Generates torque that displaces This piezoelectric cantilever is constituted by a support and a piezoelectric body, has a simple structure, and can be miniaturized.

  In the piezoelectric actuator of the present invention, the end portions of the plurality of piezoelectric cantilevers are mechanically connected. For example, in the piezoelectric cantilever located at the base end portion of the entire piezoelectric actuator, the base end portions are supported. Torque or displacement is output to the tip of the shaft. In the next piezoelectric cantilever connected to the tip of the piezoelectric cantilever, torque or displacement is output to the tip of the piezoelectric cantilever with the connecting portion as a support shaft. Thus, in the piezoelectric actuator of the present invention, the tip of each piezoelectric cantilever can be used as an output unit for outputting torque or displacement. Then, by applying a drive voltage to each piezoelectric cantilever piezoelectric body and independently controlling the bending deformation of each piezoelectric cantilever, for example, the combination of the polarity and magnitude of the drive voltage of each piezoelectric cantilever is controlled. Thus, various outputs can be obtained at the tip of each piezoelectric cantilever. At this time, since the piezoelectric body can store and hold electric charges, it is possible to hold the displacement generated at the tip of each piezoelectric cantilever even when the application of voltage is stopped.

  Further, since the plurality of piezoelectric cantilevers are connected so as to accumulate bending deformation, the output of the piezoelectric actuator (for example, torque or displacement output at the tip of the entire piezoelectric actuator) is output generated by each piezoelectric cantilever. Will be superimposed. Therefore, it is possible to obtain a large output obtained by adding the outputs generated by each piezoelectric cantilever without increasing the piezoelectric cantilever itself.

  Further, for example, when the piezoelectric cantilevers are connected so that the length directions thereof are different, an output having a plurality of directional components obtained by combining the outputs generated by the piezoelectric cantilevers as vectors is obtained from the piezoelectric actuator. Therefore, by applying drive voltages to the piezoelectric bodies of a plurality of piezoelectric cantilevers and independently controlling the bending deformation of each piezoelectric cantilever, it is possible to independently control each direction component and obtain outputs in various directions. it can.

Therefore, according to the present invention, an extended torque or displacement can be obtained with a small piezoelectric actuator. Here, the expanded torque or displacement means that the range or scale of the torque or displacement becomes wide and large, for example, a large amount of torque or displacement, torque having many directional components (high degree of freedom). Or displacement, or the output of torque or displacement obtained at the tip of a plurality of piezoelectric cantilevers.
In the piezoelectric actuator of the present invention, the electrode is formed by shaping a lower electrode layer, which is a metal thin film directly formed between a semiconductor substrate and a single-layer piezoelectric film formed on the semiconductor substrate. And an upper electrode formed by processing an upper electrode layer that is a metal thin film directly formed on the piezoelectric film.
In this case, since the upper electrode and the lower electrode are formed with the piezoelectric body interposed therebetween, the drive voltage is applied to the piezoelectric body by applying the drive voltage between the upper electrode and the lower electrode of each piezoelectric cantilever. Thus, each piezoelectric cantilever can be bent and deformed. At this time, since the upper electrode and the lower electrode are formed by processing a metal thin film directly formed, the structure is simple, and the upper electrode and the lower electrode can be easily formed using a semiconductor planar process. In addition, the piezoelectric actuator can be formed integrally with the support and the piezoelectric body, and the entire piezoelectric actuator can be manufactured using a semiconductor planar process and a MEMS process, so that mass production and yield can be improved. In addition, when the piezoelectric actuator is incorporated into a device, the entire device can be integrally formed using a semiconductor planar process and a MEMS process, so that it can be easily incorporated into another device.
Furthermore, in the piezoelectric actuator according to the present invention, the electrode is formed by partially processing the upper electrode layer and the piezoelectric film so as to be partially separated from the upper electrode and the piezoelectric body of the piezoelectric cantilever. It further includes an electrode wiring pattern for applying a driving voltage only to the piezoelectric body of the piezoelectric cantilever.
In this case, a predetermined piezoelectric cantilever among a plurality of piezoelectric cantilevers can be bent and deformed by applying a driving voltage via the electrode wiring pattern. At this time, the electrode wiring pattern is formed separately from the upper electrodes of the other piezoelectric cantilevers so as to conduct only with the upper electrodes of the predetermined piezoelectric cantilevers by shaping the two layers of the upper electrode layer and the piezoelectric film. At the same time, the piezoelectric film under the electrode wiring pattern can be formed so as to be electrically insulated from the lower electrode (interlayer insulation between the upper electrode layer and the lower electrode layer). Therefore, the electrode wiring pattern can be formed without using another material for the electrode wiring pattern by using the upper electrode layer and the piezoelectric film for forming the upper electrode and the piezoelectric body. In addition, since the upper electrode and the piezoelectric body can be formed at the same time, an electrode wiring pattern can be formed by a simple process without requiring another process.

  Further, in the piezoelectric actuator of the present invention, the plurality of piezoelectric cantilevers are arranged side by side so that both ends of each piezoelectric cantilever are adjacent to each other, and are mechanically coupled so as to be folded back with respect to each adjacent piezoelectric cantilever. The electrodes are two independent electrodes for applying different driving voltages to the piezoelectric bodies of the adjacent piezoelectric cantilevers, and the adjacent piezoelectric cantilevers are bent and deformed in opposite directions by the application of the driving voltages. Is preferred.

  In this case, each piezoelectric cantilever is arranged side by side so that both end portions are adjacent to each other, and is mechanically connected so as to be folded back with respect to each other adjacent piezoelectric cantilever. When the two piezoelectric cantilevers are bent and deformed in directions opposite to each other, the magnitude of the output generated by each piezoelectric cantilever is added. Then, since driving voltages are applied from different electrodes between adjacent piezoelectric cantilevers, for example, the odd-numbered piezoelectric cantilevers and the even-numbered piezoelectric cantilevers are independently driven from the tip end side of the entire piezoelectric actuator, It can be bent and deformed in the opposite direction.

  As a result, the output of the piezoelectric actuator as a whole is obtained by adding the magnitude of the output generated by the odd-numbered piezoelectric cantilever and the magnitude of the output generated by the even-numbered piezoelectric cantilever. Therefore, a larger output can be obtained without increasing the length of the piezoelectric cantilever, and hence the length of the piezoelectric actuator, and without increasing the influence of air damping.

  In the piezoelectric actuator of the present invention, the drive voltage applied to the piezoelectric body of the piezoelectric cantilever is preferably a direct current voltage.

  In this case, a DC voltage is applied as a driving voltage to the piezoelectric body of the piezoelectric cantilever, and the magnitude of the output generated by each piezoelectric cantilever varies linearly according to the magnitude of the DC voltage. Therefore, for example, unlike the case where the piezoelectric cantilever is resonantly driven by applying an AC voltage, an arbitrary output can be obtained by controlling the magnitude of the DC voltage. Therefore, the output part of the piezoelectric actuator can be displaced along an arbitrary path at an arbitrary speed, or an arbitrary displacement can be maintained.

  When a DC voltage is applied as a driving voltage for the piezoelectric body as described above, a sine wave, a triangular wave, a rectangular wave, a sawtooth wave, or the like can be arbitrarily selected as the waveform of the DC voltage depending on the application.

  Furthermore, in the piezoelectric actuator of the present invention, it is preferable that the support bodies of the plurality of piezoelectric cantilevers are integrally formed by processing a semiconductor substrate.

  In this case, since a plurality of piezoelectric cantilever supports are integrally formed by shape processing, the piezoelectric cantilever supports are formed as separate bodies and connected by using a processing method such as bonding or adhesion. Thus, a joining member, an adhesive, and the like are not necessary, and the alignment accuracy of each piezoelectric cantilever can be improved. In addition, since the piezoelectric cantilevers are mechanically connected by forming the support body integrally, stress is applied to the connecting portion as compared to the case where the support bodies of the piezoelectric cantilevers are formed separately and connected. The strength of the piezoelectric actuator can be improved without being concentrated. Moreover, since the support is formed from a semiconductor substrate (for example, a silicon substrate such as a single crystal silicon substrate or an SOI substrate), the support is formed by removing a part of the semiconductor substrate using a semiconductor planar process and a MEMS process. The body can be easily formed integrally. Furthermore, when the piezoelectric actuator is incorporated into a device, the entire device can be integrally formed using a semiconductor planar process and a MEMS process, and therefore, it is easy to incorporate into another device.

  In the piezoelectric actuator of the present invention, the piezoelectric bodies of the plurality of piezoelectric cantilevers are preferably formed by shaping a single-layer piezoelectric film directly formed on a semiconductor substrate.

  In this case, the piezoelectric bodies of the plurality of piezoelectric cantilevers are formed by processing a single-layer piezoelectric film directly formed on a semiconductor substrate, so that the structure is simple and it is easy to use a semiconductor planar process. Can be formed. Moreover, the support body and the piezoelectric body can be formed integrally, and no adhesive is required compared to the case where the support body and the piezoelectric body are formed and bonded separately, and the alignment accuracy is improved. It is possible to improve the strength of the piezoelectric actuator without stress concentration on the bonded portion. Furthermore, when the piezoelectric actuator is incorporated into a device, the entire device can be integrally formed using a semiconductor planar process and a MEMS process, and therefore, it is easy to incorporate into another device.

  Furthermore, in the piezoelectric actuator of the present invention, the piezoelectric film is preferably a film formed by a reactive ion plating method using arc discharge plasma.

  In this reactive ion plating method using arc discharge plasma, a source metal is heated and evaporated in a high-density oxygen plasma generated in a vacuum vessel by a plasma gun, and each metal vapor and in a vacuum vessel or on a semiconductor substrate are heated. By reacting with oxygen, a piezoelectric film is formed on the semiconductor substrate. By using this method, a piezoelectric film can be formed at high speed even at a relatively low film formation temperature, and a thick film having piezoelectric characteristics equivalent to those of a bulk piezoelectric body can be formed. Accordingly, the piezoelectric bodies of the plurality of piezoelectric cantilevers can be formed integrally with the support body by shape processing, and the output generated by each piezoelectric cantilever can be further increased.

  Alternatively, in the piezoelectric actuator of the present invention, the electrode is provided on an interlayer insulating film that covers the upper electrode, the piezoelectric body, and the lower electrode of the plurality of piezoelectric cantilevers and is partially opened on each piezoelectric cantilever. It is preferable to further include an electrode wiring pattern for applying a driving voltage to the piezoelectric body of a predetermined piezoelectric cantilever through the opening portion of the film.

  In this case, as in the case described above, a predetermined piezoelectric cantilever can be bent and deformed by applying a driving voltage via the electrode wiring pattern. At this time, since the electrode wiring pattern is provided on the interlayer insulating film, it is separated from the upper electrode of other piezoelectric cantilevers by the interlayer insulating film and electrically insulated from the lower electrode (with the upper electrode layer). Interlayer insulation with the lower electrode layer). Thus, since it is insulated by the interlayer insulation film, it is not necessary to isolate | separate the piezoelectric film under an electrode wiring pattern and to carry out interlayer insulation. Therefore, the entire piezoelectric film on the support, including the lower layer portion of the electrode wiring pattern, can be used as a piezoelectric body that generates bending deformation of the piezoelectric cantilever. That is, since the area occupation ratio of the piezoelectric body on the support can be increased, a large output can be obtained with a smaller piezoelectric actuator.

  In addition, since it is not necessary to partially separate the piezoelectric film for interlayer insulation, driving the piezoelectric actuator without affecting the bending deformation of the piezoelectric cantilever and preventing the piezoelectric cantilever from bending. The characteristics can be improved. Furthermore, by covering the piezoelectric actuator with an interlayer insulating film, resistance to external environments such as humidity can be improved.

  Examples of the material for the interlayer insulating film include inorganic insulators such as silicon oxide and silicon nitride, and organic insulators such as polyimide. The interlayer insulating film may be formed by processing the shape of the insulating film formed on the support. The electrode wiring pattern may be formed by, for example, processing a metal thin film formed on the interlayer insulating film. Thereby, the whole piezoelectric actuator can be manufactured using a semiconductor planar process and a MEMS process.

Next, a method for manufacturing a piezoelectric actuator according to the present invention relates to a method for manufacturing a piezoelectric actuator including a support and a plurality of piezoelectric cantilevers that have a piezoelectric body formed on the support and perform bending deformation by piezoelectric driving. A lower electrode layer forming step for forming a lower electrode layer that is a metal thin film on a semiconductor substrate, a piezoelectric layer forming step for forming a single-layer piezoelectric film on the lower electrode layer, and an upper portion that is a metal thin film on the piezoelectric film An upper electrode layer forming step for forming an electrode layer, a shape of the lower electrode layer, the piezoelectric film, and the upper electrode layer are processed to form a piezoelectric body of a plurality of piezoelectric cantilevers, and a driving voltage is applied to the piezoelectric body Forming an upper electrode and a lower electrode for forming the upper electrode layer and the piezoelectric film, and partially separating the upper electrode and the piezoelectric body of the piezoelectric cantilever to form a predetermined one of the plurality of piezoelectric cantilevers. a shaping step of forming an electrode wiring pattern for applying a driving voltage to the piezoelectric piezoelectric cantilevers, by processing the semiconductor substrate and are formed piezoelectric member and the upper and lower electrodes, a plurality Characterized in that it comprises a support forming step of integrally forming the support of the piezoelectric cantilever.

  According to the manufacturing method of the present invention, the piezoelectric actuator of the present invention can be easily manufactured using a semiconductor planar process and a MEMS process, and miniaturization, mass production, and yield improvement are possible. Furthermore, when the piezoelectric actuator is incorporated into a device, the entire device can be integrally formed using a semiconductor planar process and a MEMS process, and therefore, it is easy to incorporate into another device.

  At this time, since the lower electrode layer, the piezoelectric film, and the upper electrode layer are sequentially formed on the semiconductor substrate and then the shape processing is performed, for example, each layer is formed and processed for each layer, and then the next layer is formed. Compared to the case, the lower layer is flat, the film thickness at the time of film formation becomes uniform, and the accuracy of shape processing is improved. Furthermore, since the shape processing is performed after the three layers are formed, the number of steps can be reduced and the manufacturing efficiency can be further improved by processing the upper electrode layer and the piezoelectric film in the same pattern, for example.

  In the manufacturing method of the present invention, in the piezoelectric layer forming step, the piezoelectric film is preferably formed by a reactive ion plating method using arc discharge plasma.

  In this case, as described for the piezoelectric actuator of the present invention, by using an ion plating method using reactive arc discharge, a thick film having piezoelectric characteristics equivalent to that of a bulk piezoelectric material is formed. Can do. Therefore, the piezoelectric body can be formed integrally with the support by shape processing, and the output generated by each piezoelectric cantilever can be increased. Thereby, a small piezoelectric actuator capable of obtaining a large output can be easily manufactured.

In the manufacturing method of the present invention, when the upper electrode layer and the piezoelectric film are formed in the shape processing step to form the upper electrode and the piezoelectric body of each piezoelectric cantilever, one of the upper electrode layer and the piezoelectric film is formed. By separating the portions, it is possible to form an electrode wiring pattern capable of applying a driving voltage to the predetermined piezoelectric cantilever described for the piezoelectric actuator of the present invention. Thereby, an electrode wiring pattern can be formed without using another material for an electrode wiring pattern, or increasing the number of processes, and manufacturing efficiency can be improved.

  Further, in the manufacturing method of the present invention, an insulating film is formed so as to cover the piezoelectric body, the upper electrode, and the lower electrode formed in the shape processing step, and the insulating film is subjected to shape processing to thereby form each of the piezoelectric cantilevers. An interlayer insulating film forming step for forming an interlayer insulating film partially opened, and forming an electrode wiring layer made of a metal thin film on the interlayer insulating film and processing the shape of the electrode wiring layer to obtain a predetermined piezoelectric Preferably, the method further includes an electrode wiring forming step of forming an electrode wiring pattern for applying a driving voltage to the piezoelectric body of the cantilever.

  In this case, in the interlayer insulating film forming step and the electrode wiring forming step, the electrode wiring pattern capable of applying a driving voltage to the predetermined piezoelectric cantilever described for the piezoelectric actuator of the present invention can be formed on the interlayer insulating film. . At this time, the interlayer insulating film and the electrode wiring pattern can be easily formed using a semiconductor planar process and a MEMS process. Thereby, the whole piezoelectric actuator can be manufactured using a semiconductor planar process and a MEMS process, and miniaturization and mass production become easy.

[First Embodiment]
As shown in FIG. 1, the piezoelectric actuator 1 of this embodiment includes two piezoelectric cantilevers 2A and 2B. The piezoelectric cantilevers 2A and 2B are arranged on the same plane, and one piezoelectric cantilever 2A is connected to one side of the tip end b1 of the other piezoelectric cantilever 2B at a right angle to its length direction. The piezoelectric actuator 1 includes a first upper electrode 7A for applying a driving voltage to one piezoelectric cantilever 2A, a second upper electrode 7B for applying a driving voltage to the other piezoelectric cantilever 2B, And a common lower electrode 9 used as a lower electrode common to the two upper electrodes 7A and 7B.

  The piezoelectric cantilevers 2A and 2B include supports 3A and 3B, lower electrodes 4A and 4B, piezoelectric bodies 5A and 5B, and upper electrodes 6A and 6B, respectively. The first upper electrode 7A is connected to the upper electrode 6A of one piezoelectric cantilever 2A via the first upper electrode wiring 7C, and the second upper electrode 7B is connected to the upper electrode 6B of the other piezoelectric cantilever 2B. ing. The common lower electrode 9 is connected to the lower electrodes 4A and 4B of each piezoelectric cantilever. Then, by applying a voltage between the first upper electrode 7A and the common lower electrode 9, a voltage is applied between the upper electrode 6A and the lower electrode 4A, and the piezoelectric cantilever 2A is driven. Similarly, by applying a voltage between the second upper electrode 7B and the common lower electrode 9, a voltage is applied between the upper electrode 6B and the lower electrode 4B, and the piezoelectric cantilever 2B is driven.

  The support members 3A and 3B of the piezoelectric cantilevers 2A and 2B are plate-like members, and are formed of, for example, a silicon substrate such as a single crystal silicon substrate or an SOI substrate. These supports 3A and 3B are integrally formed as a single support 3 by shaping the silicon substrate. The support 3 is formed in an L shape, and its base end 3C is held by the base 10, and a portion extending from the base end 3C constitutes the support 3B of the other piezoelectric cantilever 2B. A portion extending perpendicularly from 3B constitutes a support 3A for one piezoelectric cantilever 2A. Thereby, the two piezoelectric cantilevers 2A and 2B are mechanically coupled. The pedestal 10 is also formed from a silicon substrate, and is formed integrally with the support 3 by processing the shape of the silicon substrate. As a technique for processing the shape of the silicon substrate, a semiconductor planar process and a MEMS process using a photolithography technique, a dry etching technique, or the like are used.

  The common lower electrode 9 and the lower electrodes 4A and 4B are formed by processing a metal thin film (in this embodiment, two metal thin films, hereinafter also referred to as a lower electrode layer) on the support 3 using a semiconductor planar process. Is formed. As a material of this metal thin film, for example, titanium (Ti) is used for the first layer (lower layer), and platinum (Pt) is used for the second layer (upper layer).

  The common lower electrode 9 is formed in a pad shape on the base end portion 3C of the support 3 and is electrically connected to the lower electrode 4B of the other piezoelectric cantilever 2B. The lower electrode 4B is formed on almost the entire surface of the support 3B and is electrically connected to the lower electrode 4A of one piezoelectric cantilever 2A. The lower electrode 4A is formed on almost the entire surface of the support 3A.

  The piezoelectric bodies 5A and 5B are formed separately on the lower electrodes 4A and 4B, respectively, by processing a shape of a single piezoelectric film (hereinafter also referred to as a piezoelectric layer) using a semiconductor planar process. ing. As a material of this piezoelectric film, for example, lead zirconate titanate (PZT) which is a piezoelectric material is used. The thickness of the piezoelectric film is, for example, about 1 to 10 μm. The piezoelectric film is formed by, for example, an ion plating method using reactive arc discharge. By using this method, a thick film having good piezoelectric characteristics can be formed.

  The first and second upper electrodes 7A and 7B, the second upper electrode wiring 7C, and the upper electrodes 6A and 6B are a metal thin film on the piezoelectric layer (in this embodiment, one metal thin film, hereinafter referred to as an upper electrode layer). ) Is processed by using a semiconductor planar process. For example, platinum or gold (Au) is used as the material of the metal thin film.

  The first upper electrode 7A is formed in a pad shape on the base end 3C of the support 3 and is electrically connected to the first upper electrode wiring 7C. The first upper electrode wiring 7C is linearly formed on the support 3B and is electrically connected to the upper electrode 6A of one piezoelectric cantilever 2A. The upper electrode 6A is formed on almost the entire surface of the piezoelectric body 5A. Similarly, the second upper electrode 7B is formed in a pad shape on the base end 3C of the support 3 and is electrically connected to the upper electrode 6B of the other piezoelectric cantilever 2B. The upper electrode 6B is formed on almost the entire surface of the piezoelectric body 5B.

  The first and second upper electrodes 7A and 7B are formed on the base end portion 3C of the support 3 together with the lower piezoelectric layer and the lower electrode layer, and are separated from each other. Are provided separately from the common lower electrode 9.

  Here, the separation of the first and second upper electrodes 7A and 7B will be described. 2 is a cross-sectional view taken along line II of the piezoelectric actuator 1 of FIG. As shown in FIG. 2, on the support 3B of the piezoelectric cantilever 2B, the first upper electrode wiring 7C and the lower piezoelectric body 5C are separated from the upper electrode 6B of the piezoelectric cantilever 2B and the lower piezoelectric body 5B. Is provided. Thus, the first upper electrode wiring 7C is planarly separated from the upper electrode 6B of the piezoelectric cantilever 2B, and is electrically insulated from the lower electrode 4B of the piezoelectric cantilever 2B by the piezoelectric body 5C. Therefore, the first upper electrode 7A and the second upper electrode 7B are planarly separated and insulated from the common lower electrode 4 (interlayer insulation between the upper electrode layer and the lower electrode layer). Therefore, a driving voltage can be applied independently to the piezoelectric cantilevers 2A and 2B by the first and second upper electrodes 7A and 7B.

  Next, the operation of the piezoelectric actuator 1 will be described.

  First, as a reference example, a general operation of a piezoelectric cantilever will be described using a piezoelectric actuator 131 including one piezoelectric cantilever 132A shown in FIG. In the piezoelectric actuator 131, the piezoelectric cantilever 132A includes a support 133A, a lower electrode 134A, a piezoelectric body 135A, and an upper electrode 136A. The support body 133A is integrally formed as the support body 133, the end 133B of the support body 133 is held by the pedestal 137, and the portion extending from the end part 133B constitutes the support body 133A. The piezoelectric actuator 131 is provided with an upper electrode 136 and a lower electrode 134 for applying a driving voltage to the piezoelectric cantilever 132A. The upper electrode 136 and the lower electrode 134 are formed in a pad shape on the end portion 133B of the support 133, and are connected to the upper electrode 136A and the lower electrode 134A, respectively. The details of each component are the same as those of the piezoelectric cantilever 2B of the piezoelectric actuator 1.

  FIG. 22 is a diagram schematically showing a driving state of the piezoelectric actuator 131 shown in FIG. In the piezoelectric actuator 131, a predetermined DC voltage is applied between the upper electrode 136 and the lower electrode 134 to drive the piezoelectric cantilever 132A. As a result, the piezoelectric body 135A expands and contracts according to the applied voltage, and an angular displacement α occurs at the distal end portion a1 of the piezoelectric cantilever 132A with the connection portion a0 as a fulcrum. That is, in the piezoelectric actuator 131 as a whole, an angular displacement α occurs at the distal end portion of the piezoelectric actuator 131 (the distal end portion a1 of the piezoelectric cantilever 132A) with the connection portion a0 as a fulcrum.

  In contrast, in the piezoelectric actuator 1 of the above embodiment, first, a predetermined first DC voltage (for example, −10 to +30 V) is applied between the first upper electrode 7A and the common lower electrode 9, The piezoelectric cantilever 2A is driven. As a result, the angular displacement α (for example, −1 to + 3 °) corresponding to the applied first DC voltage at the tip end a1 of the piezoelectric cantilever 2A with the connecting portion a0 between the piezoelectric cantilever 2A and the piezoelectric cantilever 2B as a fulcrum. Occurs. At the same time, a predetermined second DC voltage (for example, −10 to +30 V) is applied between the second upper electrode 7B and the common lower electrode 9 to drive the piezoelectric cantilever 2B. As a result, the angular displacement β (for example, −1 to + 3 °) corresponding to the applied second DC voltage is applied to the tip end b1 of the piezoelectric cantilever 2B with the connecting portion b0 between the piezoelectric cantilever 2B and the pedestal 10 as a fulcrum. appear.

  Accordingly, the piezoelectric actuator 1 as a whole has an angular displacement α at the distal end of the piezoelectric actuator 1 (the distal end a1 of the piezoelectric cantilever 2A) with the proximal end of the piezoelectric actuator 1 (the proximal end b0 of the piezoelectric cantilever 2B) as a fulcrum. And a displacement (α + β) having two angular components obtained by adding the vector and the angular displacement β. At this time, the first and second DC voltages can be applied independently, and the piezoelectric cantilevers 2A and 2B are driven independently, so that the angular displacement α and the angular displacement β can be controlled independently. Therefore, the piezoelectric actuator 1 can drive the tip part with two axes.

  According to the present embodiment, the two piezoelectric cantilevers 2A and 2B are connected so as to have different length directions, and a driving voltage can be independently applied to each piezoelectric cantilever, so that the tip of the piezoelectric actuator can be driven in two axes. it can.

In this embodiment, the two piezoelectric cantilevers 2A and 2B are connected at a right angle, but the number of connecting piezoelectric cantilevers and the connecting angle can be arbitrarily changed. For example, as another embodiment, three or more piezoelectric cantilevers may be connected so as to have different length directions so that the tip portion of the piezoelectric actuator is driven by three or more axes.
[Usage example of the piezoelectric actuator of the first embodiment]
FIG. 3 shows an optical deflection element (two-dimensional optical deflection element) using the piezoelectric actuator 1 of the first embodiment. In the following description, the same components as those of the first embodiment are denoted by the same reference numerals as those of the first embodiment, and the description thereof is omitted.

  In this light deflection element 11, a mirror portion 12 is connected to the tip portion of the piezoelectric actuator 1 (tip portion a 1 of the piezoelectric cantilever 2 A). The mirror unit 12 includes a mirror unit support 13 and a mirror surface reflection film 14 formed on the mirror unit support 13. The mirror support 13 is made of a silicon substrate and is formed integrally with the support 3 of the piezoelectric actuator 1. As a result, the mirror unit 12 is mechanically coupled to the piezoelectric actuator 1 and rotates according to the driving of the piezoelectric actuator 1.

  The mirror surface reflecting film 14 is formed from a metal thin film (one metal thin film in this embodiment) formed on the mirror support 13. As the material for the metal thin film, for example, gold, platinum, aluminum (Al) or the like is used. The thickness of the metal thin film is, for example, about 100 to 500 nm. The metal thin film is formed by, for example, a sputtering method or an electron beam evaporation method. The mirror surface reflecting film 14 is formed by processing a formed metal thin film using a semiconductor planar process. Other configurations are the same as those of the first embodiment.

  Next, the operation of the light deflection element 11 will be described. First, a predetermined first DC voltage is applied between the first upper electrode 7A and the common lower electrode 9, and a predetermined second DC voltage is applied between the second upper electrode 7B and the common lower electrode 9. Apply. As a result, as in the first embodiment, the piezoelectric cantilevers 2A and 2B are driven, and a displacement (α + β) having two angular components is generated at the tip of the piezoelectric actuator 1. In response to this displacement, the mirror unit 10 rotates to deflect a light beam such as a laser beam. At this time, since the piezoelectric cantilevers 2A and 2B have drive electrodes independently, the angular displacement α and the angular displacement β can be controlled independently, and the mirror portion 12 can be driven in two axes. . Further, since the piezoelectric bodies 5A and 5B can store and hold charges, the piezoelectric cantilevers 2A and 2B can hold the displacements α and β, respectively. Therefore, the deflection angle of the mirror unit 12 can be maintained even if the voltage application is stopped after applying a voltage to obtain a predetermined deflection angle.

In the optical deflection element 11 described above, the mirror portion is connected to the piezoelectric actuator in which the two piezoelectric cantilevers according to the first embodiment are connected at right angles. However, for example, there are three or more in the other embodiments. The mirror portion may be driven in a multiaxial manner with three or more axes by connecting the mirror portion to a piezoelectric actuator in which the piezoelectric cantilevers are connected in different length directions.
[Second Embodiment]
FIG. 4 shows a multi-contact switch 21 using the piezoelectric actuator 22 of the second embodiment in which three piezoelectric cantilevers 23A to 23C are connected. Note that the basic configuration of the piezoelectric actuator 22 of the present embodiment is the same as that of the piezoelectric actuator 1 of the first embodiment, and a detailed description thereof will be omitted with reference to the first embodiment.

  In the piezoelectric actuator 22 of the present embodiment, the piezoelectric cantilevers 23A to 23C are arranged on the same plane, and the first and third piezoelectric cantilevers 23A and 23C are the second (base end side) piezoelectric cantilevers 23B. Are connected to both sides of the front end portion b1 so as to be perpendicular to the length direction thereof. The piezoelectric actuator 22 includes a first upper electrode 28A for applying a driving voltage to the first piezoelectric cantilever 23A, a second upper electrode 28B for applying a driving voltage to the second piezoelectric cantilever 23B, A third upper electrode 28C for applying a driving voltage to the third piezoelectric cantilever 23C, and a common lower electrode 30 used as a lower electrode common to the first to third upper electrodes 28A to 28C.

  The piezoelectric cantilevers 23A to 23C include supports 24A to 24C, lower electrodes 25A to 25C, piezoelectric bodies 26A to 26C, and upper electrodes 27A to 27C, respectively. The first upper electrode 28A is connected to the upper electrode 27A of the first piezoelectric cantilever 23A via the first upper electrode wiring 28D. The second upper electrode 28B is connected to the upper electrode 27B of the second piezoelectric cantilever 23B. The third upper electrode 28C is connected to the upper electrode 27C of the third piezoelectric cantilever 23C via the third upper electrode wiring 28E. The common lower electrode 30 is connected to the lower electrodes 25A to 25C of the piezoelectric cantilevers 23A to 23C.

  Then, by applying a voltage between the first upper electrode 28A and the common lower electrode 30, a voltage is applied between the upper electrode 27A and the lower electrode 25A, and the piezoelectric cantilever 23A is driven. Similarly, by applying a voltage between the second upper electrode 28B and the common lower electrode 30, a voltage is applied between the upper electrode 27B and the lower electrode 25B, and the piezoelectric cantilever 23B is driven. Similarly, by applying a voltage between the third upper electrode 28C and the common lower electrode 30, a voltage is applied between the upper electrode 27C and the lower electrode 25C, and the piezoelectric cantilever 23C is driven.

  The support members 24A to 24C of the piezoelectric cantilevers 23A to 23C are plate-like members, and are integrally formed as a single support member 24 by processing the shape of the silicon substrate. These supports 24 are formed in a T-shape, and their base end portions 24D are held by the pedestals 31, and the portions extending from the base end portions 24D are the support 24B of the piezoelectric cantilever 23A on the base end side. And the portions on both sides branched from the support 24B constitute the supports 24A and 24C of the first and third piezoelectric cantilevers 22A and 23C, respectively. Thereby, the three piezoelectric cantilevers 23A to 23C are mechanically connected. The details of the support 24 and the pedestal 31 are the same as those of the support 3 and the pedestal 10 of the first embodiment.

  The common lower electrode 30 and the lower electrodes 25A to 25C are formed by processing a metal thin film (lower electrode layer) formed on the support 24 using a semiconductor planar process. Details of the lower electrode layer are the same as in the first embodiment. The common lower electrode 30 is formed in a pad shape on the end 24D of the support 24 and is electrically connected to the lower electrode 25B. The lower electrode 25B is formed on almost the entire surface of the support 24B and is electrically connected to the lower electrodes 25A and 25C. The lower electrodes 25A and 25C are formed on almost the entire surfaces of the support bodies 24A and 24C, respectively.

  The piezoelectric bodies 26A to 26C are formed from a single piezoelectric film (piezoelectric layer) formed on the lower electrode layer. The details of the piezoelectric layer are the same as in the first embodiment. The piezoelectric bodies 26A to 26C are formed separately on the lower electrodes 25A to 25C, respectively, by processing the piezoelectric layers using a semiconductor planar process.

  The first to third upper electrodes 28A to 28C, the first and third upper electrode wirings 28D and 28E, and the upper electrodes 27A to 27C are made of a metal thin film (upper electrode layer) formed on the piezoelectric layer. It is formed by shape processing using a semiconductor planar process. Details of the upper electrode layer are the same as in the first embodiment.

  The first upper electrode 28A is formed in a pad shape on the end 24D of the support 24 and is electrically connected to the first upper electrode wiring 28D. The first upper electrode wiring 28D is formed in a linear shape near the piezoelectric cantilever 23A on the support 24B, and is electrically connected to the upper electrode 27A of the first piezoelectric cantilever 23A. The upper electrode 27A is formed on almost the entire surface of the piezoelectric body 26A.

  Similarly, the second upper electrode 28B is formed in a pad shape on the end 24D of the support 24 and is electrically connected to the upper electrode 27B of the second piezoelectric cantilever 23B. The upper electrode 27B is formed on almost the entire surface of the piezoelectric body 26B.

  Similarly, the third upper electrode 28C is formed in a pad shape on the end 24D of the support 24 and is electrically connected to the third upper electrode wiring 28E. The third upper electrode wiring 28E is linearly formed near the piezoelectric cantilever 23C on the support 24B, and is electrically connected to the upper electrode 27C of the third piezoelectric cantilever 23C. The upper electrode 27C is formed on almost the entire surface of the piezoelectric body 26C.

  The first to third upper electrodes 28A to 28C are formed on the end 24D of the support 24 together with the lower piezoelectric layer and the lower electrode layer, and are provided separately from each other. It is provided separately from the electrode 30.

  At this time, as described in the first embodiment with reference to FIG. 2, the first upper electrode wiring 28D and the lower piezoelectric body 26D are separated from the upper electrode 27B and the lower piezoelectric body 26B on the support 24B. Is provided. Accordingly, the first upper electrode wiring 28D is planarly separated from the upper electrode 27B and insulated from the lower electrode 25B by the piezoelectric body 26D. Similarly, on the support 24B, the third upper electrode wiring 28E and the lower piezoelectric body 26E are provided separately from the upper electrode 27B and the lower piezoelectric body 26B. As a result, the second upper electrode wiring 28E is planarly separated from the upper electrode 27B, and is insulated from the lower electrode 25B by the piezoelectric body 26E. Therefore, the first to third upper electrodes 28 </ b> A to 28 </ b> C are separated from each other in a plane and are insulated from each other with the common lower electrode 30. Therefore, the drive voltage can be independently applied to the piezoelectric cantilevers 23A to 23C by the first to third upper electrodes 28A to 28C.

  The multi-contact switch 21 includes the above-described piezoelectric actuator 22 and first to third contacts 32A to 32C. The first contact 32A is provided to face the lower portion of the tip end a1 of the first piezoelectric cantilever 23A. The first contact 32A is turned on / off when the tip end a1 moves in the vertical direction and comes into contact / non-contact with the contact 33A. Similarly, the second contact 32B is provided facing the lower part of the tip end b1 of the second piezoelectric cantilever 23B. The second contact 32B is turned on / off when the tip end b1 moves in the vertical direction and comes into contact / non-contact with the contact 33B. Similarly, the third contact 32C is provided to face the lower part of the tip end portion c1 of the piezoelectric cantilever 23C. The third contact 32C is turned on / off when the tip end portion c1 is moved to be in contact / non-contact with the contact portion 33C. At this time, since the piezoelectric bodies 26A to 26C can store and hold charges, the displacements generated at the tip portions a1, b1, and c1 of the three piezoelectric cantilevers 23A to 23C can be held. Therefore, even if the application of this voltage is stopped after applying a voltage to obtain a predetermined connection state, this connection state (On / Off state) can be maintained.

  Next, the operation of the piezoelectric actuator 22 and the multi-contact switch 21 of this embodiment will be described. First, a predetermined first to third DC voltage is applied between the first to third upper electrodes 28A to 28C and the common lower electrode 30 to drive the piezoelectric cantilevers 23A to 23C. Thereby, in the piezoelectric cantilever 23A, an angular displacement corresponding to the first DC voltage is generated at the distal end portion a1 with the connection portion a0 as a fulcrum. Further, in the piezoelectric cantilever 23B, an angular displacement corresponding to the second DC voltage is generated at the distal end portion b1 with the connection portion b0 as a fulcrum. Further, in the piezoelectric cantilever 23C, an angular displacement corresponding to the third DC voltage is generated at the distal end portion c1 with the connection portion c0 as a fulcrum. As a result, the tip portions a1, b1, and c1 arranged to face the first to third contacts 32A to 32C as the entire piezoelectric actuator 22 move in the vertical direction, and the contacts 32A to 32C are turned on / off. The

  At this time, it is possible to select eight connection states (On / Off states) of the three contact points 32A to 32C by a combination of the first to third DC voltages to be applied. Specifically, for example, it is as shown in Table 1 below. In Table 1, the connection state {1} indicates that only the first contact 32A is in the On state. Further, the angular displacement of each of the piezoelectric cantilevers 23A to 23C is generated upward with respect to the plane on which the piezoelectric cantilevers 23A to 23C are disposed when the voltage is positive (+), and is negative (−). Shall occur in the downward direction.

According to this embodiment, the multi-contact switch can be made smaller than a multi-contact switch in which, for example, a single-axis drive type cantilever is combined by the number of contacts. Thereby, for example, a very small multiplexer can be provided. Such a small multiplexer can be used for switching a transmission path of an RF signal (GHz band) for a cellular phone.
[Third Embodiment]
As shown in FIG. 5, the piezoelectric actuator 41 according to the third embodiment includes four piezoelectric cantilevers 42A to 42D. The piezoelectric actuator 41 includes a first upper electrode 47 for applying a driving voltage to the piezoelectric cantilevers 42A and 42C, a second upper electrode 48 for applying a driving voltage to the piezoelectric cantilevers 42B and 42D, And a common lower electrode 51 used as a lower electrode common to the second upper electrodes 47 and 48. Note that the basic configuration of the piezoelectric actuator 41 of the present embodiment is the same as that of the piezoelectric actuator 1 of the first embodiment, and a detailed description thereof will be omitted with reference to the first embodiment.

  The piezoelectric cantilevers 42A to 42D are arranged in parallel on the same plane, with both end portions a0 to d0 and a1 to d1 of the piezoelectric cantilevers 42A to 42D being adjacent to each other. The adjacent portion of the end portion a0 of the piezoelectric cantilever 42A and the end portion b0 of the piezoelectric cantilever 42B are connected, and the adjacent portion of the end portion b1 of the piezoelectric cantilever 42B and the end portion c1 of the piezoelectric cantilever 42C are connected. The adjacent portions of the end c0 of the piezoelectric cantilever 42C and the end d0 of the piezoelectric cantilever 42D are connected. Accordingly, the piezoelectric cantilevers 42A to 42D are connected so as to be folded back.

  The piezoelectric cantilevers 42A to 42D include support bodies 43A to 43D, lower electrodes 44A to 44D, piezoelectric bodies 45A to 45D, and upper electrodes 46A to 46D, respectively. The first upper electrode 47 is connected to the upper electrode 46C via the first upper electrode wiring 49D, and further connected to the upper electrode 46A via the first upper electrode wiring 49B. The second upper electrode 48 is connected to the upper electrode 46D, and further connected to the upper electrode 46B via the second upper electrode wiring 50C. The common lower electrode 51 is connected to the lower electrodes 44A to 44D.

  Then, by applying a voltage between the first upper electrode 47 and the common lower electrode 51, a voltage is applied between the upper electrodes 46A, 46C and the lower electrodes 44A, 44C, respectively, and the tip of the piezoelectric actuator 41 The odd-numbered piezoelectric cantilevers 42A and 42C from the side are driven. Similarly, by applying a voltage between the second upper electrode 48 and the common lower electrode 51, a voltage is applied between the upper electrodes 46 </ b> B and 46 </ b> D and the lower electrodes 44 </ b> B and 44 </ b> D, respectively. The even-numbered piezoelectric cantilevers 42B and 42D from the part side are driven.

  The supports 43A to 43D are plate-like members, and are integrally formed as a single support 43 by processing the shape of the silicon substrate. The end portion 43E of the support body 43 is held by the pedestal 52, the portion extending from the end portion 43E constitutes the support body 43D, and the portion folded back from the support body 43D constitutes the support body 43C. The part folded back from the body 43C constitutes the support body 43B, and the part folded back from the support body 43B constitutes the support body 43A. Accordingly, the piezoelectric cantilevers 42A to 42D are mechanically connected. The details of the support 43 and the pedestal 52 are the same as those of the support 3 and the pedestal 10 of the first embodiment.

  The common lower electrode 51 and the lower electrodes 44A to 44D are formed by processing a metal thin film (lower electrode layer) formed on the support 43 using a semiconductor planar process. Details of the lower electrode layer are the same as in the first embodiment. The common lower electrode 51 is formed in a pad shape on the end portion 43E of the support body 43 and is electrically connected to the lower electrode 44D. The lower electrode 44D is formed on substantially the entire surface of the support 43D and is electrically connected to the lower electrode 44C. The lower electrode 44C is formed on substantially the entire surface of the support 43C and is electrically connected to the lower electrode 44B. The lower electrode 44B is formed on substantially the entire surface of the support body 43B and is electrically connected to the lower electrode 44A. The lower electrode 44A is formed on almost the entire surface of the support body 43A.

  The piezoelectric bodies 45A to 45D are separated from each other on the lower electrodes 44A to 44D by processing the shape of one piezoelectric film (piezoelectric layer) formed on the lower electrode layer using a semiconductor planar process, respectively. Is formed. The details of the piezoelectric layer are the same as in the first embodiment.

  The first and second upper electrodes 47 and 48, the first and second upper electrode wirings 49B, 49D and 50C, and the upper electrodes 46A to 46D are metal thin films (upper electrode layers) formed on the piezoelectric layer. ) Using a semiconductor planar process. Details of the upper electrode layer are the same as in the first embodiment.

  The first upper electrode 47 is formed in a pad shape on the end portion 43E of the support body 43, and is electrically connected to the first upper electrode wiring 49D. The first upper wiring 49D is linearly formed on the support body 43D and is electrically connected to the upper electrode 46C. The upper electrode 46C is formed on substantially the entire surface of the support 43C and is electrically connected to the first upper electrode wiring 49B. The first upper electrode wiring 49B is linearly formed on the support 43B and is electrically connected to the upper electrode 46A. The upper electrode 46A is formed on almost the entire surface of the support body 43A.

  Similarly, the second upper electrode 48 is formed in a pad shape on the end portion 43E of the support body 43 and is electrically connected to the upper electrode 46D. The upper electrode 46D is formed on almost the entire surface of the support body 43D and is electrically connected to the second upper electrode wiring 50C. The second upper electrode wiring 50C is linearly formed on the support 43C and is electrically connected to the upper electrode 46B. The upper electrode 46B is formed on almost the entire surface of the support body 43B.

  The first and second upper electrodes 47 and 48 are formed on the end portion 43C of the support 43 together with the piezoelectric layer and the lower electrode layer thereunder, and are provided separately from each other. It is provided separately from the common lower electrode 51.

  At this time, as described with reference to FIG. 2 for the first embodiment, the first upper electrode wiring 49D and the piezoelectric body below it are provided separately from the upper electrode 46D and the piezoelectric body 45D on the support 43D. Yes. Thus, the first upper electrode wiring 49D is planarly separated from the upper electrode 46D and insulated from the lower electrode 44D by the lower piezoelectric body.

  Similarly, on the support body 43C, the second upper electrode wiring 50C and the piezoelectric body thereunder are provided separately from the upper electrode 46C and the piezoelectric body 45C. As a result, the second upper electrode wiring 50C is planarly separated from the upper electrode 46C and insulated from the lower electrode 44C by the lower piezoelectric body.

  Similarly, on the support body 43B, the first upper electrode wiring 49B and the piezoelectric body therebelow are provided separately from the upper electrode 46B and the piezoelectric body 45B. As a result, the first upper electrode wiring 49B is planarly separated from the upper electrode 46B, and is insulated from the lower electrode 44B by the lower piezoelectric body.

  As described above, the first and second upper electrodes 47 and 48 are separated from each other in a plan view and are insulated from each other with the common lower electrode 51. Therefore, the first and second upper electrodes 47 and 48 can independently apply drive voltages to the odd-numbered piezoelectric cantilevers 42A and 42C and the even-numbered piezoelectric cantilevers 42B and 42D.

  Next, the operation of the piezoelectric actuator 41 of this embodiment will be described. First, a predetermined first DC voltage is applied between the first upper electrode 47 and the common lower electrode 51 to drive the odd-numbered piezoelectric cantilevers 42A and 42C. At the same time, a predetermined second DC voltage is applied between the second upper electrode 48 and the common lower electrode 51 to drive the even-numbered piezoelectric cantilevers 42B and 42D.

  At this time, the first and second DC voltages are applied so that the angular displacement between the odd-numbered piezoelectric cantilevers 42A and 42C and the even-numbered piezoelectric cantilevers 42B and 42D is generated in the opposite direction. For example, when the tip of the piezoelectric actuator 41 is displaced upward, the odd-numbered piezoelectric cantilevers 42A and 42C are displaced upward, and the even-numbered piezoelectric cantilevers 42B and 42D are displaced downward. To displace the tip portion of the piezoelectric actuator 41 in the downward direction, the reverse is performed.

  FIG. 6 is a diagram schematically showing a driving state of the piezoelectric actuator 41 of the present embodiment. In this figure, the case where the front-end | tip part of the piezoelectric actuator 41 is displaced upward is illustrated. The piezoelectric cantilever 42D has a downward angular displacement at the end d0 with the end d1 connected to the pedestal 52 as a fulcrum. Further, the piezoelectric cantilever 42C has an upward angular displacement at its end c1 with the end c0 connected to the end d0 of the piezoelectric cantilever 42D as a fulcrum. The piezoelectric cantilever 42B has a downward angular displacement at the end b0 with the end b1 connected to the end c1 of the piezoelectric cantilever 42C as a fulcrum. Further, the piezoelectric cantilever 42A has an upward angular displacement at the end a1 with the end a0 connected to the end b0 of the piezoelectric cantilever 42B as a fulcrum. By displacing the four piezoelectric cantilevers 42A to 42D in this way, a greater displacement can be obtained at the tip end a1 than, for example, the actuator 131 including one piezoelectric cantilever 132A shown in FIG. Therefore, the piezoelectric actuator 41 can obtain a large output.

  According to this embodiment, the four piezoelectric cantilevers are arranged so that both ends of each piezoelectric cantilever are arranged side by side so as to be folded back, and the adjacent piezoelectric cantilevers are bent and deformed in directions opposite to each other. It is possible to apply a driving voltage. As a result, a large output can be obtained with a small piezoelectric actuator without increasing the length of the piezoelectric cantilever, and hence the length of the piezoelectric actuator, and without increasing the influence of air damping.

In the present embodiment, four piezoelectric cantilevers are connected, but the number of piezoelectric cantilevers to be connected can be arbitrarily changed.
[Fourth Embodiment]
The piezoelectric actuator of the fourth embodiment is an AC voltage applied to drive the piezoelectric cantilever in the piezoelectric actuator of the third embodiment. Since the configuration of the piezoelectric actuator of this embodiment is the same as that of the third embodiment, in the following description, the same reference numerals as those of the third embodiment are used and description thereof is omitted.

  In the operation of the piezoelectric actuator of the fourth embodiment, a predetermined first AC voltage is applied between the first upper electrode 47 and the common lower electrode 51 to drive the piezoelectric cantilevers 42A and 42C. Further, a predetermined second AC voltage is applied between the second upper electrode 48 and the common lower electrode 51 to drive the piezoelectric cantilevers 42B and 42D. The first AC voltage and the second AC voltage are obtained by inverting the phases.

  According to the present embodiment, an AC voltage having a frequency near the primary resonance point of the piezoelectric cantilevers 42A to 42D is applied to drive the piezoelectric actuator 41 to resonate, thereby increasing the magnitude of the applied voltage. Output can be obtained. In addition, an AC voltage having a frequency lower than the primary resonance point of the piezoelectric cantilevers 42A to 42D is applied (for example, about 300 Hz or less in the drive characteristic test shown in FIG. 8 described later) to make the piezoelectric actuator 41 non-resonant. By driving, a predetermined output corresponding to the magnitude of the applied voltage can be stably obtained as in the case where a DC voltage is applied. In a non-resonant drive region having a frequency lower than the primary resonance point and below a predetermined frequency, a constant output can be stably obtained at an arbitrary drive frequency and drive speed.

  Next, a test of the drive characteristics of the piezoelectric actuator 41 of this embodiment will be described with reference to FIGS. In addition, the piezoelectric actuator 41 was manufactured by the manufacturing method of 6th Embodiment mentioned later.

  As test conditions, an AC voltage A of 0 to +30 [V] is applied between the first upper electrode 47 and the common lower electrode 51, and between the second upper electrode 48 and the common lower electrode 51, An AC voltage B of +30 to 0 [V] was applied. The applied AC voltages A and B are shown in the graph of FIG. In the graph of FIG. 7, the horizontal axis is time, and the vertical axis is applied voltage. As shown in FIG. 7, the AC voltage A and the AC voltage B are obtained by inverting the phases.

  The graph of FIG. 8 shows the amount of displacement of the tip end a1 of the piezoelectric actuator 41 during driving as a test result. In the graph of FIG. 8, the horizontal axis is the frequency (drive frequency) of the applied AC voltages A and B, and the vertical axis is the relative value when the displacement amount of the tip a is 1 during non-resonant drive. is there. The primary resonance point exists at about 700 Hz, and the amount of displacement is 10 times or more that in non-resonance driving. Further, a substantially constant displacement amount can be obtained up to about 500 Hz regardless of the driving frequency.

In the present embodiment, the drive voltage of the piezoelectric actuator of the third embodiment is an AC voltage. However, the same drive is possible even if the drive voltage of the piezoelectric actuator of the fifth, seventh, and eighth embodiments described later is an AC voltage. Characteristics can be obtained.
[Fifth Embodiment]
As in the third embodiment, the piezoelectric actuator 61 of the fifth embodiment shown in FIG. 9 is configured by connecting four piezoelectric cantilevers 62A to 62D. FIG. 9 shows the piezoelectric cantilevers 62 </ b> A to 62 </ b> D of the piezoelectric actuator 61. FIG. 10 shows an enlarged view of region II in FIG. The basic structure of the piezoelectric actuator 61 is the same as that of the piezoelectric actuator 41 of the third embodiment, and the structures related to the support bodies 43A to 43D of the four piezoelectric cantilevers 42A to 42D are slightly different. In the following description, the same components as those of the third embodiment are denoted by the same reference numerals as those of the third embodiment, and the description thereof is omitted.

  In the piezoelectric actuator 61 of the present embodiment, the support bodies 43A to 43D of the four piezoelectric cantilevers 62A to 62D are respectively composed of straight portions 64A to 64D and connecting portions 65A to 65D, 66A to 66D at both ends thereof. . Adjacent piezoelectric cantilever connecting portions 66A, 66B, connecting portions 65B, 65C, and connecting portions 66C, 66D are connected in a U-shape. Further, the connecting portion 65D of the piezoelectric cantilever 62D is connected to and held by the base end portion 43E of the support body 43 on the pedestal 53.

  The lower electrodes 44A to 44D of the four piezoelectric cantilevers 62A to 62D respectively support the piezoelectric cantilevers 62A to 62D (the entire combined linear and connecting portions) 64A to 66A, 64B to 66B, 64C to 66C, 64D. It is formed on almost the entire surface on ˜66D. The piezoelectric bodies 45A to 45D of the piezoelectric cantilevers 62A to 62D and the upper electrodes 46A to 46D are formed on almost the entire surface of the linear portions 64A to 64D of the support bodies of the piezoelectric cantilevers 62A to 62D. The first upper electrode wires 67a and 67b and the second upper electrode wires 68a and 68b of the piezoelectric actuator 61 are formed on the straight portions 64B to 64D and on the side portions on the connecting portions 65B to 65D and 66A to 66D. ing.

  The first upper electrode wiring 67b and the piezoelectric body below it are separated from the upper electrode 46D and the piezoelectric body 45D of the piezoelectric cantilever 62D on the linear portion 64D of the piezoelectric cantilever 62D as described in FIG. 2 for the first embodiment. Is provided. As a result, the first upper electrode wiring 67b is planarly separated from the upper electrode 46D and insulated from the lower electrode 44D by the lower piezoelectric body.

  Similarly, the first and second upper electrode wirings 67a and 68a and the piezoelectric bodies below the first upper electrode wirings 67a and 68a are arranged on the linear portions 64B and 64C of the piezoelectric cantilevers 62B and 62C, respectively. The piezoelectric bodies 45B and 45C are provided separately. Further, on the connecting portions 65B to 65D and 66A to 66D, the first upper electrode wirings 67a and 67b and the lower piezoelectric body thereof are separated from the second upper electrode wirings 68a and 68b and the lower piezoelectric body thereof. Is provided.

  As described above, the first and second upper electrodes 47 and 48 of the piezoelectric actuator 61 are separated from each other in a plan view and are insulated from each other with the common lower electrode 51. Therefore, the drive voltage can be independently applied to the piezoelectric cantilevers 62 </ b> A to 62 </ b> D by the first and second upper electrodes 47 and 48. Other configurations and operations are the same as those in the third embodiment.

According to the present embodiment, similar to the piezoelectric actuator 41 of the third embodiment, a small and large output can be obtained.
[Sixth Embodiment]
In FIG. 11, the manufacturing method of the piezoelectric actuator of 6th Embodiment is shown. In this manufacturing method, the piezoelectric actuator 41 of the third embodiment is manufactured. 11A to 11G schematically show a cross section of the piezoelectric actuator 41 in FIG.

  As shown in FIG. 11A, an SOI substrate 81 is used as a substrate on which the support body 43 is formed. The SOI substrate 81 is a bonded substrate of single crystal silicon (also referred to as an active layer 81a or an SOI layer) / silicon oxide (intermediate oxide film layer 81b) / single crystal silicon (handling layer 81c). Regarding the thickness of each layer of the SOI substrate, for example, the thickness of the active layer 81a is 5 to 100 μm, the thickness of the intermediate oxide film layer 81b is 0.5 to 2 μm, and the thickness of the handling layer 81c is 100 to 600 μm. Further, the surface of the active layer 81a is subjected to an optical polishing process.

  First, as shown in FIG. 11B, thermally oxidized silicon films 82a and 82b are formed on the front surface (active layer 81a side) and the back surface (handling layer 81c side) of the SOI substrate 81 by a thermal oxidation furnace (diffusion furnace). (Thermal oxide film formation step). The thickness of the thermally oxidized silicon films 82a and 82b is, for example, 0.1 to 1 μm.

  Next, as shown in FIG. 11C, a lower electrode layer 83, a piezoelectric layer 84, and an upper electrode layer 85 are sequentially formed on the surface of the SOI substrate 81.

  First, in the lower electrode layer forming step, a lower electrode layer 83 made of a two-layer metal thin film is formed on the thermally oxidized silicon film 82a on the active layer 81a side of the SOI substrate 81. As a material for the lower electrode layer 83, titanium is used for the first (lower) metal thin film, and platinum is used for the second (upper) metal thin film. Each metal thin film is formed by, for example, sputtering or electron beam evaporation. The thickness of each metal thin film is, for example, about 30 to 100 nm for the first titanium layer and about 100 to 300 nm for the second platinum layer.

  Next, in the piezoelectric layer forming step, a piezoelectric layer 84 made of a single piezoelectric film is formed on the lower electrode layer 83. As a material of the piezoelectric layer 84, lead zirconate titanate (PZT) which is a piezoelectric material is used. The thickness of the piezoelectric film is, for example, about 1 to 10 μm. The piezoelectric film is formed by, for example, an ion plating method using reactive arc discharge. The ion plating method using reactive arc discharge is specifically described in Japanese Patent Application Laid-Open Nos. 2001-234331, 2002-177765, and 2003-81694 by the applicant of the present application. Use the technique.

  In this reactive ion plating method using arc discharge plasma, a source metal is heated and evaporated in a high-density oxygen plasma generated in a vacuum vessel by a plasma gun, and each metal vapor and in a vacuum vessel or on a semiconductor substrate are heated. By reacting with oxygen, a piezoelectric film is formed on the semiconductor substrate. By using this method, a piezoelectric film can be formed at high speed even at a relatively low film formation temperature. In particular, when a piezoelectric film is formed by an arc discharge reactive ion plating method, a seed layer is formed as a foundation by, for example, a chemical solution deposition method (CSD (Chemical Solution Deposition) method). A piezoelectric film having characteristics can be formed.

  The piezoelectric film may be formed by, for example, a sputtering method or a sol-gel method. However, by using an ion plating method using reactive arc discharge, a thick film having piezoelectric characteristics equivalent to that of a bulk piezoelectric body can be formed.

  Next, in the upper electrode layer forming step, an upper electrode layer 85 made of a single metal thin film is formed on the piezoelectric layer 84. As a material of the upper electrode layer 85, platinum or gold is used. The metal thin film is formed by, for example, a sputtering method or an electron beam evaporation method. The thickness of the metal thin film is, for example, about 10 nm to 200 nm.

  Next, as shown in FIG. 11D, in the shape processing step, the shapes of the upper electrode layer 85, the piezoelectric layer 84, and the lower electrode layer 83 are processed, and the upper electrodes 45A to 45D of the piezoelectric cantilevers 42A to 42D. The piezoelectric bodies 44A to 44D and the lower electrodes 43A to 43D are formed. Specifically, first, a resist material is patterned on the upper electrode layer 85 using a photolithographic technique. Next, using the patterned resist material as a mask, the upper electrode layer 85 and the piezoelectric layer 84 are dry-etched using a RIE (Reactive Ion Etching) apparatus. Thereby, the first and second upper electrodes 47 and 48, the upper electrodes 46A to 46D, and the piezoelectric bodies 45A to 45D are formed. At this time, first and second upper electrode wirings 49B, 49d, and 50C are also formed.

  Similarly, a resist material is patterned on the lower electrode layer 83 using a photolithographic technique. Next, using the patterned resist material as a mask, dry etching is performed on the lower electrode layer 83 using an RIE apparatus. Thereby, the common lower electrode 51 and the lower electrodes 44A to 44D are formed. The electrode pad of the common lower electrode 51 for applying a voltage is formed like an end e1 where the lower electrode layer 83 is exposed as shown in FIG. The electrode pads of the second upper electrodes 47 and 48 are formed like an end portion e2 where the upper electrode layer 85 is exposed.

  Next, as shown in FIGS. 11E to 11G, the support 43 and the pedestal 52 are formed in the support formation step. First, as shown in FIG. 11E, the shapes of the thermally oxidized silicon film 82a and the active layer 81a (single crystal silicon) on the active layer 81a side are processed. First, a resist material is patterned using a photolithographic technique, and the thermally oxidized silicon film 82a on the active layer 81a side is dry-etched using an RIE apparatus, using the patterned resist material as a mask. Next, with the same mask, the silicon of the active layer 81a is processed using a Deep-RIE apparatus. The Deep-RIE apparatus is a dry etching apparatus used in micromachining technology, and is an apparatus capable of deeply digging silicon vertically.

  Next, as shown in FIG. 11F, the shape of the handling layer 81c is processed. First, a resist material is patterned on the back surface of the SOI substrate 81 using a photolithographic technique, and the thermally oxidized silicon film 82b on the handling layer 81c side is dry-etched using an RIE apparatus, using the patterned resist material as a mask. . Next, using the same mask, the silicon of the handling layer 81c is processed using a Deep-RIE apparatus. Thereby, the back side of the movable part of the piezoelectric actuator 41 is deeply dug into a hollow state, so that the movable part (piezoelectric cantilevers 42A to 42D) of the piezoelectric actuator 41 can be driven in the vertical direction.

  Next, as shown in FIG. 11G, the intermediate oxide film layer 81b of the SOI substrate 81 is removed. Specifically, using the same mask as in FIG. 11E, the intermediate oxide film layer 81b is dry-etched from the back side of the SOI substrate using an RIE apparatus. Accordingly, the piezoelectric cantilever 42 </ b> A to 42 </ b> D can be driven by separating the movable portion of the piezoelectric actuator 61 from the surrounding SOI substrate 81.

  Through the above steps, the piezoelectric actuator 41 is manufactured.

  According to this manufacturing method, since the piezoelectric actuator 41 can be integrally formed using a semiconductor planar process and a MEMS process, manufacturing is easy, and yield improvement and mass production are possible. Further, when the piezoelectric actuator 41 is incorporated into a device, the entire device can be integrally formed using a semiconductor planar process and a MEMS process, so that the piezoelectric actuator 41 can be easily incorporated into another device. .

In the manufacturing method of the present embodiment, the piezoelectric actuator 41 of the third embodiment is manufactured. However, the piezoelectric actuator 41 of the first, second, fourth, and fifth embodiments is also used for manufacturing. Can do.
[Seventh Embodiment]
The piezoelectric actuator 71 according to the seventh embodiment shown in FIG. 12 is the same as the piezoelectric actuator 61 according to the fifth embodiment except that an interlayer insulating film is provided for insulation between the upper electrode layer and the lower electrode layer. FIG. 12 shows a top view of the piezoelectric cantilevers 72 </ b> A to 72 </ b> D of the piezoelectric actuator 71. FIG. 13 is a perspective view of the piezoelectric actuator 71 of FIG. In this figure, the interlayer insulating film 73 and the first and second upper electrode wirings 76 a, 76 b, 77 a, 77 b are shown separately for the sake of explanation, but actually, they are sequentially stacked on the support 43. ing. In the following description, the same components as those of the fifth embodiment are denoted by the same reference numerals as those of the fifth embodiment, and the description thereof is omitted.

  In the piezoelectric actuator 71 of this embodiment, only the first and second upper electrodes 47 and 48 and the upper electrodes 46A to 46D are formed by processing the upper electrode layer. An interlayer insulating film 73 is formed on the upper electrode layer. The interlayer insulating film 73 is formed by processing an insulating film formed on the upper electrode layer by a semiconductor planar process. As a material of the interlayer insulating film 73, a silicon nitride film or a silicon oxide film is used. Note that as the material of the interlayer insulating film 73, other inorganic insulating materials or organic insulating materials such as polyimide may be used.

  The interlayer insulating film 73 is formed on the entire surface of the support 43 so as to cover the lower electrodes 44A to 44D, the piezoelectric bodies 45A to 45D, and the upper electrodes 46A to 46D. The interlayer insulating film 73 is formed with first openings 74a to 74c for the first upper electrode wiring and second openings 75a to 75c for the second upper electrode wiring. Although not shown, the interlayer insulating film 73 has openings formed on the pads of the first and second upper electrodes 47 and 48 and the common lower electrode 51 on the end 43E of the supports 43A to 43D. ing.

  Further, first upper electrode wirings 76 a and 76 b and second upper electrode wirings 77 a and 77 b are formed on the interlayer insulating film 73. The first and second upper electrode wirings 76a, 76b, 77a, 77b are formed by processing a shape of an electrode wiring layer made of a metal thin film formed on an insulating film by a semiconductor planar process. As a material for the electrode wiring layer, gold, platinum, aluminum or the like is used as a material for the electrode pattern for wiring.

  One end of the first upper electrode wiring 76a is formed so as to cover the first opening 74a on the support 43A, is electrically connected to the upper electrode 46A, and is wired to the support 43C through the support 43B. . The first upper electrode wiring 76a is formed such that the other end covers the first opening 74b on the support 43C, and is electrically connected to the upper electrode 46C.

  The first upper electrode wiring 76b is formed so that one end thereof covers the first opening 74c and is electrically connected to the upper electrode 46C. The first upper electrode wiring 76b passes over the support 43D and is not shown, but is wired up to the support 43E. The other end is provided on the first upper electrode 47 and is electrically connected.

  The second upper electrode wiring 77a is formed so that one end thereof covers the second opening 75a on the support 43B, is electrically connected to the upper electrode 46C, and is routed to the support 43D through the support 63C. ing. The second upper electrode wiring 77a is formed so that the other end covers the second opening 75b on the support body 43D, and is electrically connected to the upper electrode 46D.

  The second upper electrode wiring 77b is formed so that one end thereof covers the second opening 75c on the support body 43D and is electrically connected to the upper electrode 46D. Although not shown, the third upper electrode wiring 77b is wired up to the support 43E, and the other end is provided on the second upper electrode 48 and is conductive.

  14 is a cross-sectional view of the piezoelectric actuator 71 of FIG. 12 taken along the line III-III. As shown in FIG. 14, an interlayer insulating film 73 is formed so as to cover the lower electrode 44D, the piezoelectric body 45D, and the upper electrode 46D on the support 43D. The second upper electrode wiring 77b is formed so as to cover the second opening 75c, and the second upper electrode wiring 77b and the upper electrode 46D are electrically connected. On the other hand, since the first upper electrode wiring 76b is formed on the interlayer insulating film 73, it is isolated from the upper electrode 46D and insulated from the lower electrode 44D. By providing the interlayer insulating film 73 in this manner, it is not necessary to form and separate the first upper electrode wiring 76b together with the piezoelectric body therebelow as shown in FIG. 2 for the first embodiment. Therefore, in the present embodiment, the piezoelectric body 45D formed on almost the entire surface of the support body 63D is used to cause bending deformation of the piezoelectric cantilever 62D including the lower layer portion of the first upper electrode wiring 76b. .

  According to this embodiment, as in the fifth embodiment, the four piezoelectric cantilevers are arranged so that both end portions of each piezoelectric cantilever are arranged side by side and folded so that the adjacent piezoelectric cantilevers are folded. A driving voltage can be applied so as to bend and deform in opposite directions. As a result, a large output can be obtained with a small piezoelectric actuator without increasing the length of the piezoelectric cantilever, and hence the length of the piezoelectric actuator, and without increasing the influence of air damping.

  Furthermore, in the present embodiment, since the upper electrode wiring is provided on the interlayer insulating film, it is not necessary to isolate the piezoelectric layer under the upper electrode wiring and perform interlayer insulation. Therefore, the entire piezoelectric film on the support can be used as a piezoelectric body that generates bending deformation of the piezoelectric cantilever. That is, since the area occupation ratio of the piezoelectric body on the support can be increased, a large output can be obtained with a smaller piezoelectric actuator.

In the fifth embodiment, the portion of the piezoelectric layer separated to insulate the layers may affect the bending deformation of the piezoelectric cantilever, and may prevent the bending deformation of the piezoelectric cantilever. In this embodiment, since it is not necessary to form the said part, the drive characteristic of a piezoelectric actuator can be improved. Furthermore, by covering the piezoelectric actuator with an interlayer insulating film, resistance to external environments such as humidity can be improved.
[Eighth Embodiment]
The piezoelectric actuator 70 according to the eighth embodiment shown in FIG. 15 is insulated from the upper electrode layer and the lower electrode layer in the piezoelectric actuator 41 according to the third embodiment, similarly to the piezoelectric actuator 71 according to the seventh embodiment. The interlayer insulating film is provided. FIG. 15 shows a top view of the piezoelectric actuator 70. In the following description, the same components as those of the third and seventh embodiments are denoted by the same reference numerals as those of the third and seventh embodiments, and the description thereof is omitted.

  In the piezoelectric actuator 70 of the present embodiment, as in the seventh embodiment, only the first and second upper electrodes 47 and 48 and the upper electrodes 46A to 46D are formed by shaping the upper electrode layer. An interlayer insulating film 73 is formed on the upper electrode layer. The interlayer insulating film 73 is formed on the entire surface of the support 43 so as to cover the lower electrodes 44A to 44D, the piezoelectric bodies 45A to 45D, and the upper electrodes 46A to 46D. Furthermore, on the interlayer insulating film 73, first and second upper electrode wirings 76a, 76b, 77a, 77b are formed. The details of the interlayer insulating film 73 and the first and second upper electrode wirings 76a, 76b, 77a, 77b are the same as in the seventh embodiment.

  One end of the first upper electrode wiring 76a is formed so as to cover the first opening 74a on the support 43A, is electrically connected to the upper electrode 46A, and is wired to the support 43C through the support 43B. . The first upper electrode wiring 76a is formed such that the other end covers the first opening 74b on the support 43C, and is electrically connected to the upper electrode 46C.

  The first upper electrode wiring 76b is formed so that one end thereof covers the first opening 74c and is electrically connected to the upper electrode 46C. The first upper electrode wiring 76b passes through the support body 43D and is wired to the support body 43E, and the other end is provided on the first upper electrode 47 and is conductive.

  The second upper electrode wiring 77a is formed so that one end thereof covers the second opening 75a on the support 43B, is electrically connected to the upper electrode 46C, and is routed through the support 43C to the support 43D. ing. The second upper electrode wiring 77a is formed so that the other end covers the second opening 75b on the support body 43D, and is electrically connected to the upper electrode 46D.

  The second upper electrode wiring 77b is formed so that one end thereof covers the second opening 75c on the support body 43D and is electrically connected to the upper electrode 46D. The third upper electrode wiring 77b is wired up to the support 43E, and the other end is provided on the second upper electrode 48 and is conductive. Other configurations and operations are the same as those of the third embodiment.

  According to the present embodiment, similar to the piezoelectric actuator of the third embodiment, a small and large output can be obtained.

  Furthermore, in the present embodiment, as in the seventh embodiment, since the upper electrode wiring is provided on the interlayer insulating film, it is not necessary to isolate the piezoelectric layer under the upper electrode wiring and perform interlayer insulation. Accordingly, the area occupation ratio of the piezoelectric body on the support can be further increased, the driving characteristics of the piezoelectric actuator can be improved, and a large output can be obtained with a smaller piezoelectric actuator. Furthermore, by covering the piezoelectric actuator with an interlayer insulating film, resistance to external environments such as humidity can be improved.

In the present embodiment, the piezoelectric actuator of the third embodiment is provided with an interlayer insulating film. However, as another embodiment, the piezoelectric actuator of the first, second, and fourth embodiments includes an interlayer insulating film. May be provided. In this case, for example, in the optical deflection element using the piezoelectric actuator of the first embodiment, the mirror surface reflection film and the upper electrode wiring are made of the same material, and the electrode wiring pattern and the mirror surface reflection film are made of the same metal thin film. It can be formed by shape processing.
[Ninth Embodiment]
16 and 17 show a manufacturing method according to the ninth embodiment. The piezoelectric actuator 70 of the eighth embodiment is manufactured by the manufacturing method of the present embodiment. The manufacturing method of this embodiment includes the step of forming the interlayer insulating film 73 and the step of forming the first and second upper electrode wirings 76a, 76b, 77a, 77b in the manufacturing method of the sixth embodiment. Is. In the following description, the same processing as in the sixth embodiment will be described with reference to the sixth embodiment. 16 (a) to 16 (g) and FIGS. 17 (h) to (j) schematically show a cross section of the piezoelectric actuator 70 in FIG.

  As shown in FIG. 16A, an SOI substrate 81 similar to that of the sixth embodiment is used as a substrate on which the support body 43 is formed. First, as shown in FIG. 16B, thermally oxidized silicon films 82a and 82b are formed on the front surface (active layer 81a side) and the back surface (handling layer 81c side) of the SOI substrate 81 by a thermal oxidation furnace (thermal oxide film). Forming step). Next, as shown in FIG. 16C, a lower electrode layer 83, a piezoelectric layer 84, and an upper electrode layer 85 are sequentially formed on the surface of the SOI substrate 81 (lower electrode layer forming step, piezoelectric layer forming step). , Upper electrode layer forming step). The thermal oxide film forming step, the lower electrode layer forming step, the piezoelectric layer forming step, and the upper electrode layer forming step are the same as the steps in the sixth embodiment.

  Next, as shown in FIG. 16D, the shapes of the upper electrode layer 83, the piezoelectric layer 84, and the lower electrode layer 85 are processed to form the upper electrode, the piezoelectric body, and the lower electrode (shape processing step). . The details of the shape processing step are the same as in the seventh embodiment. Thereby, the first and second upper electrodes 47 and 48, the upper electrodes 46A to 46D, and the piezoelectric bodies 45A to 45D are formed. However, at this time, the first and second upper electrode wirings 76a, 76b, 77a, 77b are not formed. The electrode pad of the common lower electrode 51 for applying a voltage is formed like an end e1 where the lower electrode layer 83 is exposed as shown in FIG. The electrode pads of the second upper electrodes 47 and 48 are formed like the end portion e2 where the upper electrode layer 85 is exposed.

  Next, as shown in FIGS. 16E and 16F, an interlayer insulating film 73 is formed in the interlayer insulating film forming step. First, as shown in FIG. 16E, an insulating film 86, which is a thin film of an insulator, is formed on the entire surface of the SOI substrate 81 on the active layer 81a side. As the material of the insulating film 86, a silicon nitride film or a silicon oxide film is used. The insulating film 86 is formed by using, for example, a CVD (Chemical Vapor Deposition) method. The thickness of the insulating film 86 is, for example, about 100 to 500 nm.

  Note that an organic insulating material such as polyimide may be used as the material of the insulating film 86. In this case, the film is formed by using, for example, a spin coating method. At this time, the thickness of the insulating film 86 is, for example, about 0.5 to 5 μm.

  Next, as shown in FIG. 16F, the shape of the insulating film 86 formed on the entire surface is processed. Specifically, first, a resist material is patterned on the insulating film 86 using a photolithographic technique. Next, dry etching is performed on the insulating film 86 using an RIE apparatus using the patterned resist material as a mask. Thereby, an interlayer insulating film 73 partially opened on the upper electrode of each piezoelectric cantilever is formed. Note that, like the opening f1 of the interlayer insulating film 73 shown in FIG. 16F, the electrode pad of the common lower electrode 51 for applying a voltage is opened, and the opening f2 of the interlayer insulating film 73 is formed. In addition, the electrode pads of the first and second upper electrodes 47 and 48 for applying a voltage are opened. The first openings 74a, 74b, 74c and the second openings 75a, 75b, 75c are also formed like the opening f2.

  Next, in the electrode wiring formation step, an electrode wiring pattern for the upper electrode is formed as shown in FIG. First, the electrode wiring layer 87 made of a single metal thin film is formed on the entire surface of the SOI substrate 71 on the thermal oxide film 82a side. As a material for the electrode wiring layer 87, for example, gold, platinum, aluminum or the like is used. The electrode wiring layer 87 is formed by using, for example, a sputtering method or a vapor deposition method. The thickness of the electrode wiring layer 87 is, for example, about 100 to 500 nm.

  Next, the shape of the electrode wiring layer 87 is processed. Specifically, first, a resist material is patterned on the electrode wiring layer 87 using a photolithographic technique. Next, dry etching is performed on the electrode wiring layer 87 using an RIE apparatus, using the patterned resist material as a mask. As a result, as shown in FIG. 15, the electrodes 44A to 46D are electrically connected to the openings 44a, 44b, 45a, and 45b, and the electrodes are electrically connected to the first and second upper electrodes 47 and 48 on the support 63E. Wiring patterns (upper electrode wirings) 76a, 76b, 77a, 77b are formed.

  Next, as shown in FIGS. 17H to 17J, the SOI substrate 81 is processed to form the support 63 and the pedestal 52 of the piezoelectric actuator 71 (support formation step). The support forming step is the same as the step of the seventh embodiment.

  The piezoelectric actuator 70 is manufactured through the above steps.

  According to the manufacturing method of the present embodiment, since the piezoelectric actuator 70 can be integrally formed using a semiconductor planar process and a MEMS process, as in the sixth embodiment, manufacturing is easy and yield is improved. And mass production becomes possible. Furthermore, when the piezoelectric actuator 70 is incorporated in a device, the entire device can be integrally formed using a semiconductor planar process and a MEMS process, so that the piezoelectric actuator 71 can be easily incorporated in another device. .

In the present embodiment, the piezoelectric actuator of the eighth embodiment (the piezoelectric actuator having the interlayer actuator on the piezoelectric actuator of the third embodiment) is manufactured. However, the manufacturing method of the present embodiment is the first method. The piezoelectric actuator of the second and fourth embodiments having an interlayer insulating film, and the piezoelectric actuator of the seventh embodiment (the piezoelectric actuator of the fifth embodiment having an interlayer insulating film) are manufactured. Can also be used.
[Tenth embodiment]
FIG. 18 shows a variable capacitor using the piezoelectric actuator 91 of the tenth embodiment. The piezoelectric actuator 91 of this embodiment is a combination of four piezoelectric actuators 92 to 95. The variable capacitor is obtained by connecting a capacitor portion 96 to the tip portions of the four piezoelectric actuators 92 to 95 of the piezoelectric actuator 91. In addition, since the basic structure of each piezoelectric actuator 92-95 is the same as 5th or 7th Embodiment, description is abbreviate | omitted below.

  In the piezoelectric actuator 91 of the present embodiment, the four piezoelectric actuators 92 to 95 are arranged on the same plane, and the tip portions 92a1 to 95a1 are connected to the four corners of the rectangular conductor support portion 97, respectively.

  One pair of piezoelectric actuators 92 and 93 are provided to face each other on one side of the conductor support portion 97. Further, the other pair of piezoelectric actuators 94 and 95 are provided to face each other on the other side of the conductor support portion 97. Further, the one pair of piezoelectric actuators 92 and 93 and the other pair of piezoelectric actuators 94 and 94 are provided to face each other with the conductor support portion 97 interposed therebetween.

  The pair of piezoelectric actuators 92 and 93 has a base end portion 92d1 and 93d2 adjacent to the support base end portion 104A held on a pedestal 105A provided on one side of the conductor support portion 97. It is supported by being connected to two matching corners. Further, the other pair of piezoelectric actuators 94 and 95 has their base end portions 94d1 and 95d1 adjacent to the support base end portion 104B held on the base 105B provided on the other side of the conductor support portion 97. It is supported by being connected to two matching corners.

  The four piezoelectric actuators 92 to 95 include four piezoelectric cantilevers 92A to 92D, 93A to 93D, 94A to 94D, and 95A to 95D, respectively. The piezoelectric actuators 92 to 95 include supports 100 to 103 that are integrally formed as supports for the piezoelectric cantilevers 92A to 92D, 93A to 93D, 94A to 94D, and 95A to 95D, respectively.

  The conductor holding portion 97 and the supports 100 to 103, 104A, and 104B are integrally formed as a single support by shaping the silicon substrate. As a result, the conductor holding portion 97 is mechanically connected to the four piezoelectric actuators 92 to 95 and is displaced according to the driving of the piezoelectric actuators 92 to 95. Further, the pedestals 105A and 105B are also formed integrally with the one support body by shaping the silicon substrate.

  On one pedestal 105A, an electrode set 109A for applying a driving voltage to the piezoelectric actuators 92 and 93 is provided. The electrode set 109A includes a first upper electrode 106A for applying a drive voltage to the piezoelectric cantilevers 92A, 92C, 93A, and 93C, and a second upper portion for applying a drive voltage to the piezoelectric cantilevers 92B, 92D, 93B, and 93D. An electrode 107A and a common lower electrode 108A used as a lower electrode common to the first and second upper electrodes 106A and 107A are provided.

  Similarly, an electrode set 109B for applying a driving voltage to the other pair of piezoelectric actuators 94 and 95 is provided on the other pedestal 105B. The electrode set 109B includes a first upper electrode 106B for applying a driving voltage to the piezoelectric cantilevers 94A, 94C, 95A, and 95C, and a second upper portion for applying a driving voltage to the piezoelectric cantilevers 94B, 94D, 95B, and 95D. An electrode 107B and a common lower electrode 108B used as a lower electrode common to the first and second upper electrodes 106B and 107B are provided.

  Although not shown, the first and second upper electrodes 106A, 106B, 107A, and 107B are connected to the piezoelectric cantilever 92A via the first and second upper electrode wires as in the fifth or seventh embodiment. To 92D, 93A to 93D, 94A to 94D, and 95A to 95D.

  The capacitor portion 96 is configured by a plate-like upper conductor 98 held on the lower surface of the conductor holding portion 97, and a plate-like lower conductor 99 provided to face the upper conductor 98 with a predetermined interval. The By changing the distance between the upper conductor 98 and the lower conductor 99, the capacitance of the variable capacitor becomes variable.

  Next, the operation of the variable capacitor using the piezoelectric actuator 91 of this embodiment will be described. FIG. 19 is a diagram schematically showing the driving state of the variable capacitor. This figure illustrates the case where the upper conductor 98 of the variable capacitor is driven in the vertical direction. First, a predetermined first DC voltage is applied between the first upper electrodes 106A and 106B and the common lower electrodes 108A and 108B, and between the second upper electrodes 107A and 107B and the common lower electrodes 108A and 108B. Then, a predetermined second DC voltage having a polarity opposite to that of the first DC voltage is applied. As a result, the piezoelectric actuators 92 to 95 are driven, and displacement occurs in the same predetermined direction (for example, upward direction) at the distal end portions 92a1 to 95a1 according to the applied voltage. Similarly, by applying voltages having opposite polarities to the first and second DC voltages, the piezoelectric actuators 92 to 95 are driven, and the tip portions 92a1 to 95a1 have the same predetermined direction (for example, downward) according to the applied voltage. Direction).

  Due to this displacement, the conductor holding portion 97 and the upper conductor 98 are translated in the vertical direction. Accordingly, as indicated by the dotted line in FIG. 19, the upper conductor 98 is translated in the vertical direction to change the distance between the upper conductor 98 and the lower conductor 99, thereby controlling the capacitance of the variable capacitor. At this time, since the piezoelectric bodies of the piezoelectric cantilevers 92A to 92D, 93A to 93D, 94A to 94D, and 95A to 95D can store and hold charges, they are generated at the tip portions 92a1 to 95a1 of the four piezoelectric actuators 92 to 95. Displacement can be maintained. Therefore, even if the application of this voltage is stopped after applying a voltage to obtain a predetermined capacity, this capacity can be maintained.

  According to the present embodiment, since a large output can be obtained by the piezoelectric actuators 92 to 95, the variable range of the distance between the upper conductor 98 and the lower conductor 99 is large, and the capacitance can be controlled in a wide range.

  In the above-described variable capacitor, the upper conductor 98 is connected to the piezoelectric actuator 91 for driving, but the lower conductor 99 may be connected to the piezoelectric actuator 91 for driving. Furthermore, as another embodiment, the upper conductor 98 and the lower conductor 99 may be connected to different piezoelectric actuators to drive both.

In this embodiment, four piezoelectric actuators similar to those in the fifth or seventh embodiment are used in combination. However, four piezoelectric actuators in the third or eighth embodiment are used in combination. Also good.
[Eleventh embodiment]
FIG. 20 shows an optical deflection element 123 using the piezoelectric actuator 111 of the eleventh embodiment. The piezoelectric actuator 111 of the present embodiment is a two-axis drive type piezoelectric actuator in which two piezoelectric actuators 112 and 113 are combined. The optical deflection element 123 is a two-dimensional optical deflection element in which a mirror 115 is connected to the tip of the two-axis drive type piezoelectric actuator 111. The basic configuration of each of the piezoelectric actuators 112 and 113 is the same as that in the fifth or seventh embodiment, and thus the description thereof is omitted below.

  In the piezoelectric actuator 111 of the present embodiment, the two piezoelectric actuators 112 and 113 are arranged on the same plane, and one of the piezoelectric actuators 112 has a base end portion 112d1 and a tip end portion 113a1 of the other piezoelectric actuator 113. Are connected so that their output directions are orthogonal to each other. The biaxially driven piezoelectric actuator 114 includes electrode sets 116 and 117 for applying a driving voltage to the piezoelectric actuators 112 and 113, respectively.

  The piezoelectric actuators 112 and 113 include piezoelectric cantilevers 112A to 112D and 113A to 113D, respectively. The piezoelectric actuators 112 and 113 include supports 118 and 119 integrally formed as supports for the piezoelectric cantilevers 112A to 112D and 113A to 113D, respectively. These supports 118 and 119 are integrally formed as a single support 120 by shaping a silicon substrate. The base 120 of the support 120 is held on the pedestal 122, and the portion extending from the base 121 constitutes the support 119 of the other piezoelectric actuator 113, and the portion extending from the support 119 is The support body 118 of one piezoelectric actuator 112 is constituted. Thereby, the two piezoelectric actuators 112 and 113 are mechanically connected. The pedestal 122 is also formed from a silicon substrate and is formed integrally with the support 120.

  The electrode set 116 of one piezoelectric actuator 112 includes a first upper electrode 116a for applying a driving voltage to the odd-numbered piezoelectric cantilevers 112A and 112C from the tip end side, and an even-numbered piezoelectric cantilever 112B and 112D from the tip end side. A second upper electrode 116b for applying a driving voltage to the first and second upper electrodes 116a and 116b, and a common lower electrode 116c used as a lower electrode common to the first and second upper electrodes 116a and 116b. Similarly, the electrode set 117 of the other piezoelectric actuator 113 includes a first upper electrode 117a for applying a driving voltage to the odd-numbered piezoelectric cantilevers 113A and 113C from the tip end side, and an even-numbered piezoelectric cantilever from the tip end side. A second upper electrode 117b for applying a driving voltage to 113B and 113D and a common lower electrode 117c used as a lower electrode common to the first and second upper electrodes 117a and 117b are provided.

  Each electrode 116 a, 116 b, 116 c, 117 a, 117 b, 117 c of the electrode set 116, 117 is formed in a pad shape on the end 121 of the support 120. Although not shown, the first and second upper electrodes 116a, 116b, 117a, and 117b are connected to the piezoelectric cantilevers 112A to 112D via the first and second upper electrode wires, as in the sixth embodiment. It is connected to predetermined upper electrodes 113A to 113D.

  In the light deflection element 123, the mirror part 124 has a rectangular shape, and one side thereof is connected to the tip part of the piezoelectric actuator 111 (tip part 112a1 of one piezoelectric actuator 112). The mirror unit 124 includes a mirror unit support 125 and a mirror surface reflection film 126 formed on the mirror unit support 125. The details of the mirror surface reflecting film 126 are the same as those of the mirror surface reflecting film 14 of the light deflection element 11 using the piezoelectric actuator 1 of the first embodiment. The mirror support 125 is formed of a silicon substrate and is formed integrally with the support 120 of the piezoelectric actuator 111, like the mirror support 13 of the light deflection element 11. As a result, the mirror unit 124 is mechanically coupled to the piezoelectric actuator 111 and rotates according to the driving of the piezoelectric actuator 111.

  Next, the operation of the piezoelectric actuator 111 and the light deflection element 123 of this embodiment will be described. First, a predetermined first DC voltage is applied between the first upper electrode 116a and the common lower electrode 116c, and a polarity opposite to that of the first DC voltage is applied between the second upper electrode 116b and the common lower electrode 116c. A predetermined second DC voltage is applied. As a result, an angular displacement α is generated at the distal end portion 112a1 of the piezoelectric actuator 112 with the proximal end portion 112d1 of the piezoelectric actuator 112 as a fulcrum.

  At the same time, a predetermined third DC voltage is applied between the first upper electrode 117a and the common lower electrode 117c, and the third DC voltage is reversed between the second upper electrode 117b and the common lower electrode 117c. A predetermined fourth DC voltage having a polarity is applied. As a result, an angular displacement β is generated at the distal end portion 113a1 of the piezoelectric actuator 113 with the base end portion 113d1 of the piezoelectric actuator 113 as a fulcrum.

  As a result, displacement (α + β) having two angle components is generated at the tip of the piezoelectric actuator 111 as a whole. In response to this displacement, the mirror unit 124 rotates to deflect a light beam such as a laser beam. At this time, since the piezoelectric actuators 112 and 113 have drive electrodes independently, the angular displacement α and the angular displacement β can be controlled independently, and the mirror unit 124 can be driven in two axes. . Further, since the piezoelectric bodies of the piezoelectric cantilevers 112A to 112D and 113A to 113D can store and hold electric charges, the piezoelectric actuators 111 and 112 can hold the displacements α and β, respectively. Therefore, the deflection angle of the mirror part 124 can be maintained even if the application of this voltage is stopped after applying a voltage to obtain a predetermined deflection angle.

  According to this embodiment, two piezoelectric actuators that are small and can obtain a large output are connected so that the output directions are orthogonal to each other, and a driving voltage can be applied to each piezoelectric actuator independently. Therefore, the piezoelectric actuator is a two-axis drive type that can obtain a large output with a small size. And in the above-mentioned optical deflection | deviation element 123, a small and big deflection angle can be obtained by connecting a mirror part to the front-end | tip part of the piezoelectric actuator of this embodiment.

  In the present embodiment, the two piezoelectric actuators are connected so that the output directions are orthogonal to each other. However, the connecting angle can be arbitrarily changed, and the two piezoelectric actuators only need to have different output directions.

  In this embodiment, two piezoelectric actuators are connected so that the output directions are orthogonal to each other, and a mirror portion is connected to the tip of the two piezoelectric actuators to form a two-dimensional optical deflection element. However, as another embodiment, three or more The piezoelectric actuators may be coupled so that the output directions are different. Then, by connecting a mirror portion to the tip portion of the piezoelectric actuator, it is possible to obtain a light deflection element that can be driven in a multi-axis direction of three or more axes and can obtain a small and large deflection angle.

  In this embodiment, two piezoelectric actuators similar to those in the fifth or seventh embodiment are used in combination. However, two piezoelectric actuators in the third or eighth embodiment are used in combination. Also good.

The perspective view which shows the structure of the piezoelectric actuator in 1st Embodiment of this invention. FIG. 2 is a cross-sectional view taken along the line I-I of the piezoelectric actuator of FIG. 1. The perspective view which shows the structure of the optical deflection | deviation element using the piezoelectric actuator of FIG. The perspective view which shows the structure of the multi-contact switch which uses the piezoelectric actuator in 2nd Embodiment of this invention. The perspective view which shows the structure of the piezoelectric actuator in 3rd Embodiment of this invention. Explanatory drawing which shows the action | operation of the piezoelectric actuator of FIG. The graph which shows an example of the applied voltage of the piezoelectric actuator in 4th Embodiment of this invention. The graph which shows an example of the operation characteristic of the piezoelectric actuator of FIG. The perspective view which shows the structure of the piezoelectric actuator in 5th Embodiment of this invention. Explanatory drawing which shows the structure of the piezoelectric actuator of FIG. Explanatory drawing which shows the manufacturing method in 6th Embodiment of this invention. The top view which shows the structure of the piezoelectric actuator in 7th Embodiment of this invention. The perspective view which shows the structure of the piezoelectric actuator of FIG. FIG. 14 is a sectional view of the piezoelectric actuator of FIG. 13 taken along the line III-III. The top view which shows the structure of the piezoelectric actuator in 8th Embodiment of this invention. Explanatory drawing which shows the manufacturing method in 9th Embodiment of this invention. Explanatory drawing which shows the manufacturing method of the piezoelectric actuator of FIG. The perspective view which shows the structure of the variable capacitor using the piezoelectric actuator in 10th Embodiment of this invention. Explanatory drawing which shows the action | operation of the variable capacitor of FIG. The perspective view which shows the structure of the optical deflection | deviation element using the piezoelectric actuator in 11th Embodiment of this invention. The perspective view which shows the structure of the conventional piezoelectric actuator. Explanatory drawing which shows the action | operation of the piezoelectric actuator of FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Piezoelectric actuator, 2A, 2B ... Piezoelectric cantilever, 3, 3A, 3B ... Support body, 4A, 4B ... Lower electrode, 5A, 5B ... Piezoelectric body, 6A, 6B ... Upper electrode, 7A ... 1st upper electrode, 7B ... second upper electrode, 7C ... second upper electrode wiring, 9 ... common lower electrode, 10 ... pedestal,
DESCRIPTION OF SYMBOLS 11 ... Light deflection element, 12 ... Mirror part, 13 ... Mirror surface reflection film, 14 ... Mirror part support body,
DESCRIPTION OF SYMBOLS 21 ... Multi-contact switch, 22 ... Piezoelectric actuator, 23A-23C ... Piezoelectric cantilever, 24, 24A-24C ... Support body, 25A-25C ... Lower electrode, 26A-26C ... Piezoelectric body, 27A-27C ... Upper electrode, 28A- 28C ... first to third upper electrodes, 28D, 28E ... first and third upper electrode wirings, 30 ... common lower electrode, 31 ... pedestal, 32A-32C ... first to third contacts,
DESCRIPTION OF SYMBOLS 41 ... Piezoelectric actuator, 42A-42D ... Piezoelectric cantilever, 43, 43A-43D ... Support body, 44A-44D ... Lower electrode, 45A-45D ... Piezoelectric body, 46A-46D ... Upper electrode, 47 ... First upper electrode, 48 ... second upper electrode, 49B, 49D ... first upper electrode wiring, 50C ... second upper electrode wiring, 51 ... common lower electrode, 52 ... pedestal,
61 ... Piezoelectric actuator, 62A to 62D ... Piezoelectric cantilever, 64A to 64D ... Linear portion, 65A to 65D, 66A to 66D ... Connection portion, 67a, 67b ... First upper electrode wiring, 68a, 68b ... Second upper electrode wiring,
70 ... Piezoelectric actuator, 71 ... Piezoelectric actuator, 72A to 72D ... Piezoelectric cantilever, 73 ... Interlayer insulating film, 74a-74c ... First opening, 75a-75c ... Second opening, 76a, 76b ... First upper electrode wiring , 77a, 77b ... second upper electrode wiring,
81 ... SOI substrate, 81a ... active layer, 81b ... intermediate oxide film layer, 81c ... handling layer, 82a, 82b ... thermally oxidized silicon film, 83 ... lower electrode layer, 84 ... piezoelectric layer, 85 ... upper electrode layer, 86 ... Insulating film, 87 ... Electrode wiring layer,
91 ... Piezoelectric actuator, 92-95 ... Piezoelectric actuator, 92A-92D, 93A-93D, 94A-94D, 95A-95D ... Piezoelectric cantilever, 96 ... Capacitor part, 97 ... Conductor holding part, 98 ... Upper conductor, 99 ... Bottom Side conductors, 100 to 103, 104A, 104B ... support, 105A, 105B ... pedestal, 106A, 106B ... first upper electrode, 107A, 107B ... second upper electrode, 108A, 108B ... common lower electrode, 109A, 109B ... Electrode set,
DESCRIPTION OF SYMBOLS 111 ... Piezoelectric actuator, 112, 113 ... Piezoelectric actuator, 112A-112D, 113A-113D ... Piezoelectric cantilever, 116, 117 ... Electrode set, 116a, 117a ... First upper electrode, 116b, 117b ... Second upper electrode, 116c, 117c ... Common lower electrode, 118-121 ... Support, 122 ... Pedestal,
123: Light deflection element, 124: Mirror part, 125 ... Mirror part support, 126 ... Mirror surface reflection film,
131 ... Piezoelectric actuator, 132A ... Piezoelectric cantilever, 133, 133A ... Support, 134, 134A ... Lower electrode, 135A ... Piezoelectric, 136, 136A ... Upper electrode, 137 ... Pedestal.

Claims (3)

A plurality of piezoelectric cantilevers having a support and a piezoelectric body formed on the support and performing bending deformation by piezoelectric driving, and a plurality of electrodes for applying a driving voltage to the piezoelectric bodies of the plurality of piezoelectric cantilevers Independently
The plurality of piezoelectric cantilevers are mechanically coupled at their ends so as to accumulate each bending deformation, and each piezoelectric cantilever is independently bent and deformed by application of the driving voltage ,
The plurality of piezoelectric cantilever supports are integrally formed by processing a semiconductor substrate,
The piezoelectric bodies of the plurality of piezoelectric cantilevers are formed by processing a single-layer piezoelectric film directly formed on the semiconductor substrate,
The electrode is formed directly on the piezoelectric film and a lower electrode formed by processing a lower electrode layer, which is a metal thin film formed directly on the semiconductor substrate, between the piezoelectric film and the piezoelectric film. An upper electrode formed by processing a shape of the upper electrode layer, which is a metal thin film, and a shape processing of the upper electrode layer and the piezoelectric film so as to be partially separated from the upper electrode and the piezoelectric body of the piezoelectric cantilever. An electrode wiring pattern for applying a driving voltage to a piezoelectric body of a predetermined piezoelectric cantilever among the plurality of piezoelectric cantilevers . The piezoelectric actuator according to claim 1, wherein
The plurality of piezoelectric cantilevers are arranged side by side so that both ends of each piezoelectric cantilever are adjacent to each other, and are mechanically coupled so as to be folded back with respect to each adjacent piezoelectric cantilever,
The plurality of electrodes are two independent electrodes for applying different driving voltages to the piezoelectric bodies of the adjacent piezoelectric cantilevers,
The piezoelectric actuator, wherein the adjacent piezoelectric cantilevers are bent and deformed in opposite directions by the application of the driving voltage. In a method of manufacturing a piezoelectric actuator comprising a support and a plurality of piezoelectric cantilevers that have a piezoelectric body formed on the support and perform bending deformation by piezoelectric driving,
A lower electrode layer forming step of forming a lower electrode layer which is a metal thin film on a semiconductor substrate;
A piezoelectric layer forming step of forming a single-layer piezoelectric film on the lower electrode layer;
An upper electrode layer forming step of forming an upper electrode layer which is a metal thin film on the piezoelectric film;
Processing the shapes of the lower electrode layer, the piezoelectric film, and the upper electrode layer to form piezoelectric bodies of the plurality of piezoelectric cantilevers, and an upper electrode and a lower electrode for applying a driving voltage to the piezoelectric bodies And forming the upper electrode layer and the piezoelectric film into a shape so as to be partially separated from the upper electrode and the piezoelectric body of the piezoelectric cantilever. A shape processing step for forming an electrode wiring pattern for applying a driving voltage to the piezoelectric body;
And a support body forming step of integrally forming a plurality of support bodies of the piezoelectric cantilevers by processing the semiconductor substrate on which the piezoelectric body, the upper electrode, and the lower electrode are formed. A method for manufacturing a piezoelectric actuator.

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