JP2018073958A - Cantilever piezoelectric element, sensor and vibration element using piezoelectric element, and manufacturing method of piezoelectric element - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a cantilever piezoelectric element suitable for large area, a high resolution and high accuracy sensor or vibration element capable of increasing the area, and a manufacturing method of cantilever piezoelectric element capable of reducing waste of material and environmental load.SOLUTION: A cantilever piezoelectric element includes a first electrode, an insulation layer having an opening and a through hole, a second electrode insulated by the insulation layer, and a cantilever. The cantilever includes a structure consisting of first and second conductive layers and a piezoelectric material layer sandwiched by the first and second conductive layers, where any one or more of the conductive layers and the piezoelectric material layer are resin-containing layers. The cantilever constitutes a displacement part in such a state that the first and second conductive layers are connected conductively with the first or second electrode directly or by an interconnect line, while partially floating above the opening.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a cantilever piezoelectric element, a sensor and a vibration element using the piezoelectric element, and a method for manufacturing the piezoelectric element.

  In recent years, the development of services that feed back the results by installing sensor devices in every place of the living space and recognizing the living environment and living situation has been attempted. For example, it is safer and safer by deploying a wide variety of sensors in residences for watching over the elderly, in each product for inventory management and distribution management, and in the human body for health management. Realization of a new society is expected. Against this backdrop, production of 1 trillion sensors per year is predicted (see Non-Patent Document 1), and further improvement in sensor performance is required. In particular, a sensor matrix that detects and maps a target event over a wide range by spreading a sensor over a large area has attracted attention. The advantage of large area deployment is the frequency and accuracy of sensing. As an example of improving the frequency, it is possible to detect the behavior of the subject without interruption by laying sensors on the floor of a residence over a large area. As an example of accuracy improvement, when detecting the amount of activity from the movement of human muscles, it is difficult to separate noise and signal from only one narrow point, but it is more reliable by averaging over a wide area It is possible to perform high sensing. In order to realize these, sensors that can be made into a sheet or matrix and have a large area have been proposed (see Patent Documents 1 and 2).

  A cantilever structure is known as a structure that is highly versatile and capable of highly sensitive sensing. The cantilever structure has a floating portion that does not contact the substrate. It is widely available as a sensor mechanism that the floating portion operates according to a detection target. The cantilever structure is the core structure of a sensor device that can be applied to both physical and chemical phenomena. For example, as a structure having a functional group that adsorbs a specific substance on the surface of the floating part of the cantilever structure, it has been reported that the cantilever can be applied to a sensor due to a change in weight caused when the substance adsorbs. (Refer nonpatent literature 2). It has also been reported that a structure in which a piezoelectric material is introduced into a floating portion of a cantilever structure can operate as a strain sensor by generating a voltage when strain is applied (see Non-Patent Document 3).

  In particular, as in Non-Patent Document 3, a cantilever using a piezoelectric material uses a voltage as a detection signal. Therefore, for example, the influence of noise is higher than that of a capacitance type using a distance between a floating portion and a substrate. Highly accurate sensor can be realized. Further, since the piezoelectric material is used, the cantilever portion can be vibrated or deformed by applying a voltage.

  Also, a hollow structure element is known in which the inside of a recess formed in a substrate is a hollow space, and a cantilever-shaped layer is disposed on the hollow space (see Patent Document 3). In Patent Document 3, an acoustic device is exemplified, and the cantilever-shaped layer has a structure in which a lower electrode, a piezoelectric film, and an upper electrode are stacked. Moreover, in patent document 3, various devices provided with a hollow structure, for example, an acceleration sensor, a pressure sensor, etc. are mentioned as a hollow structure element.

  As a result of a prior literature search for a cantilever-shaped sensor, the following Patent Document 4 was known. Patent Document 4 relates to a piezoelectric cantilever pressure sensor, and includes a piezoelectric cantilever that is attached to one end of a substrate and extends on a cavity. The piezoelectric cantilever includes a first electrode, a second electrode, and the first electrode. A structure comprising a piezoelectric element electrically connected to these between the second electrodes is shown. Also shown is a sensor array in which a plurality of piezoelectric cantilever sensors are arranged in a matrix.

  Further, when a prior literature search was conducted on the transfer technology, the following patent document 5 was known. Patent Document 5 discloses a thin film forming method for forming a thin film in a state where a space of a concave portion is maintained on a substrate provided with a concave portion for sealing. Specifically, a coating liquid containing a thin film raw material to be a thin film material and an organic material composed of an organic compound having a surface energy smaller than that of the thin film raw material is applied to the main surface of the substrate to form a coating film, and then the coating is performed. A method is shown in which a thin film is formed on the main surface of the substrate by bringing the film into contact with the main surface of the substrate, applying load and heating, and then releasing the base material.

JP-A-8-154903 JP-A-2005-150146 JP 2005-342817 A JP 2005-249785 A JP 2008-251816 A

R. Bogue, Sens. Rev. 34, 137 (2014). H. Hou, X. Bai, C. Xing, N. Gu, B. Zhang and J. Tang, Anal. Chem, 85, 2010 (2013). L. Gammelgaard, P. A. Rasmussen, M. Calleja, P. Vettiger, and A. Boisen, Appl. Phys. Lett. 88, 113508 (2006).

  Conventionally, the cantilever structure that can be used for various sensors and acoustic devices has been made with a displacement portion made of metal, Si-based inorganic compound, oxide, or the like (see Patent Documents 3 and 4). The displacement amount of the displacement member is determined by the Young's modulus, and the Young's modulus is determined by the material of the displacement member. If the material of the displacement member is limited only to the inorganic compound film, the range of Young's modulus selectivity becomes narrow, and there is a problem that sensitivity adjustment is limited in the case of a sensor, and large displacement in the case of a vibration element. There is a problem that the amount cannot be formed.

  There are still many problems in applying the cantilever structure to a high-performance sensor matrix developed over a large area.

  First, it is difficult to develop and manufacture a three-dimensional microfabrication such as a cantilever shape over a large area. In order to displace the displacement portion of the cantilever structure in a floating state from the base body, it is necessary to form a hollow portion between the base body and the cantilever. Conventionally, it has been manufactured by a method in which a hollow portion is formed by etching and removing a sacrificial layer after a process is performed in a state where a sacrificial layer is provided in a hollow portion (see Patent Documents 3 and 4). In the conventional manufacturing method, since a sacrificial layer is used, there are problems that the process of forming the hollow structure is complicated, it is difficult to increase the area, and waste of materials and energy is generated.

  Further, in order to obtain a high-performance sensor matrix, it is desired that the sensor matrix has high accuracy over a wide area and high resolution. Therefore, in particular, in forming a sensor matrix using a cantilever structure, in addition to a configuration in which a large number of cantilever beams are arranged in the same direction (referred to as a single axis), a configuration in which a large number is arranged in a plurality of directions (multiple configurations). Called the axis). That is, multi-axis means that the cantilever structures are arranged in a matrix so that the beam direction of the cantilever becomes two or more directions. The cantilever shape often has anisotropy in sensitivity due to its structure. Here, when the detection target has anisotropy, if the anisotropy coincides with the low-sensitivity axis of the cantilever, the sensing accuracy decreases. Therefore, it is desired to develop a cantilever matrix structure suitable for multi-axis.

  The present invention is intended to solve these problems. The cantilever member is novel, has a simple structure and is suitable for increasing the area, and a high resolution and high performance using the piezoelectric element. It is an object of the present invention to provide a sensor and a vibration element capable of increasing the area with high accuracy, and a method for manufacturing the piezoelectric element capable of reducing waste of materials and environmental load.

In order to achieve the above object, the present invention has the following features.
(1) a first electrode, an insulating layer provided with an opening and a through hole on the first electrode, and a second layer that is partially laminated with the first electrode and is insulated by the insulating layer A cantilever portion having a structure comprising an electrode, a first and second conductive layer, and a piezoelectric material layer sandwiched between the conductive layers, wherein at least one of the conductive layer and the piezoelectric material layer is a resin-containing layer; Each of the conductive layers is conductively connected to the first electrode or the second electrode directly or from a connection line, and a part of the conductive layer is floated on the opening. A cantilever-type piezoelectric element characterized by being.
(2) When the conductive layer far from the insulating layer is the first conductive layer and the conductive layer near is the second conductive layer, the first conductive layer is a connection line extending from the second electrode. (2), wherein the second conductive layer is electrically connected to the first electrode via the through hole and a connection line. Cantilever type piezoelectric element.
(3) When the conductive layer far from the insulating layer is the first conductive layer, and the close conductive layer is the second conductive layer, the second conductive layer is a connection line extending from the second electrode. (1), wherein the first conductive layer is electrically connected to the first electrode via the through hole and a connection line. Cantilever type piezoelectric element.
(4) When the conductive layer far from the insulating layer is the first conductive layer, and the close conductive layer is the second conductive layer, the first conductive layer is a connection line extending from the second electrode. And the second conductive layer is electrically connected to the first electrode via the conductive connection portion in the through hole (1). The cantilever piezoelectric element described in the above.
(5) When the conductive layer far from the insulating layer is the first conductive layer and the conductive layer closer to the insulating layer is the second conductive layer, the second conductive layer is directly electrically connected to the second electrode. The cantilever type piezoelectric element according to (1), wherein the first conductive layer is electrically connected to the first electrode through a through hole and a connection line.
(6) The first electrode and the second electrode have a matrix structure that intersects via the insulating layer, the cantilever portions are arranged in a plurality of intersecting regions, and the insulating layer is mesh-shaped. The cantilever type piezoelectric element according to any one of (1) to (5), wherein the cantilever type piezoelectric element is provided.
(7) The first electrode and the second electrode have a matrix structure that intersects with the insulating layer interposed therebetween, the cantilever portions are arranged in the plurality of intersecting regions, and the insulating layer has a mesh shape The cantilever type piezoelectric element according to any one of (1) to (5), wherein the plurality of cantilever portions in the intersecting region are arranged in one or more axial directions in the longitudinal direction. .
(8) A sensor comprising the cantilever piezoelectric element according to any one of (1) to (7).
(9) A vibrating element comprising the cantilever piezoelectric element according to any one of (1) to (7).
(10) A first electrode, an insulating layer having an opening and a through-hole, and a part of the first electrode are laminated on the element base material, and the second is insulated through the insulating layer. A first conductive layer and a piezoelectric material layer are formed in this order on the low surface energy material on the surface of the transfer substrate, and a second conductive layer containing a resin is formed on the piezoelectric material layer. By forming a part of the second conductive layer in contact with the insulating layer side of the element base material in a state where the second conductive layer is not completely cured, the first conductive layer is formed by a process. The cantilever piezoelectric element according to (1), wherein the layer, the piezoelectric material layer, and the second conductive layer are transferred from the low surface energy material to the element substrate side to form a cantilever part. Manufacturing method.
(11) A first electrode, an insulating layer having an opening and a through-hole, and a part of the first electrode are laminated on the element base material, and the second is insulated via the insulating layer. A first conductive layer, a piezoelectric material layer, and a second conductive layer are formed in order on a low surface energy material that is formed with an electrode and provided on the surface of the transfer substrate, and a part of the second conductive layer An adhesive layer / conductive layer containing a resin is formed thereon, and the adhesive layer / conductive layer is brought into contact with the insulating layer side of the element substrate in a state where the adhesive layer / conductive layer is not completely cured. (1), wherein the first conductive layer, the piezoelectric material layer, and the second conductive layer are transferred from the low surface energy material to the element substrate side to form a cantilever portion. Manufacturing method of cantilever type piezoelectric element.

  In this invention, since the member which comprises a cantilever part contains a resin content layer, the cantilever part which has a desired Young's modulus etc. can be designed according to the use of the target sensor or vibration element. As in the prior art (Patent Document 4 etc.), in the cantilever type piezoelectric element, since the cantilever part is made only of an inorganic material, it is hard and it is necessary to further provide an elastic layer (inorganic material). It is possible to have a minimum structure of conductive layer / insulating piezoelectric material layer / conductive layer.

  The cantilever type piezoelectric element of the present invention has a large area by aligning the beam direction of the cantilever part in one direction or a plurality of directions and arranging a plurality of cantilever structures on two mutually insulated electrodes. can do. By forming a plurality of cantilever structures of the present invention into a matrix, a high-resolution, high-accuracy sensor matrix or vibration element matrix can be obtained.

  In the present invention, when the matrix is formed, the opening portion of the insulating layer is just a mesh, so that the insulating layer is a mesh-like insulating layer, so that the displacement portion and the element base that are the floating portion of the cantilever portion are formed. A large gap with the material can be obtained.

  When multiple cantilever structures are arranged with the beam direction of the cantilever part aligned in multiple directions, multiple axial directions are detected even if the detection target is anisotropic pressure or multidirectional pressure Therefore, it is possible to improve the accuracy of the sensing function, detect the direction of anisotropy, and map. Moreover, detection by higher resolution and higher frequency can be performed by detecting in the multi-axis directions.

  According to the present invention, since the unnecessary portion is not removed after forming the sacrificial layer as in the prior art, but by transfer, a cantilever-type piezoelectric element is formed by a method of additionally forming a film on the necessary portion. An element can be realized. Therefore, according to the present invention, the piezoelectric element can be manufactured with a low environmental load and can be formed in a reduced process.

It is a schematic diagram of the basic structure of the cantilever type piezoelectric element of the first embodiment, and is a plan view seen from above the upper electrode side. (A) is sectional drawing of the A-A 'line of FIG. 1, (b) is sectional drawing of a B-B' line. It is a figure of the cantilever part of 1st Embodiment, (a) is the top view which looked at the cantilever part from the top, (b) is sectional drawing of the dotted line of (a). It is the top view which looked at the modification of the cantilever type piezoelectric element of 3rd Embodiment from the upper electrode side. (A) is sectional drawing of the A-A 'line | wire of FIG. 4, (b) is sectional drawing of a B-B' line | wire. It is the top view which looked at the modification of the cantilever type piezoelectric element of 4th Embodiment from the upper electrode side. (A) is sectional drawing of the A-A 'line of FIG. 6, (b) is sectional drawing of a B-B' line. It is the top view which looked at the modification of the cantilever type piezoelectric element of 5th Embodiment from the upper electrode side. (A) is sectional drawing of the A-A 'line of FIG. 8, (b) is sectional drawing of a B-B' line. It is a top view explaining the cantilever type | mold piezoelectric element made into the matrix by the uniaxial direction of 6th Embodiment. It is a top view explaining the cantilever type piezoelectric element formed into a matrix in the multi-axis direction according to the seventh embodiment.

  Embodiments of the present invention will be described below.

  The present inventor paid attention to the following points in a cantilever-shaped displacement member that can be used for a sensor or the like in a research process for developing a cantilever structure. First, the range of selection of the material for the displacement member is not limited to the conventional inorganic compounds, but a new option is realized, and second, a cantilever structure suitable for realizing a sensor matrix is realized. That is. Therefore, in the present embodiment, in the cantilever type piezoelectric element, the cantilever part has a structure including at least the resin-containing layer, thereby realizing a novel cantilever part. In addition, a cantilever-type piezoelectric element that can be made into a matrix and multi-axis has been realized.

  The cantilever means a cantilever shape, with one long end fixed and the other end movable. The cantilever structure refers to a structure including a cantilever part.

  The cantilever piezoelectric element of the present invention includes a first electrode, an insulating layer having an opening and a through hole on the first electrode, and a part of the first electrode laminated, and the insulating layer A second electrode to be insulated and a cantilever part which is one of the features of the present invention are provided. The cantilever part of the present invention has a structure composed of first and second conductive layers and a piezoelectric material layer sandwiched between the conductive layers, and at least one of the conductive layer and the piezoelectric material layer is a resin-containing layer. is there. For example, the piezoelectric material layer may be formed of a resin layer. Alternatively, when the conductive layer far from the insulating layer is the first conductive layer and the close conductive layer is the second conductive layer, the second conductive layer may be formed of a resin-containing layer. Or you may form these combinations and all the layers by a resin content layer. That is, there is no particular limitation as long as one or more of the conductive layer and the piezoelectric material layer is a resin-containing layer. In the cantilever portion, each of the conductive layers is electrically connected to the first electrode or the second electrode directly or through a connection line, and a part of the cantilever portion is floated on the opening.

(First embodiment)
This embodiment will be described below with reference to FIGS.

  FIG. 1 is a schematic diagram of a basic structure of a cantilever piezoelectric element in the present embodiment. FIG. 1 is a plan view seen from above the upper electrode side. The cantilever structure of the present embodiment includes an element substrate (not shown), a lower electrode 1 formed on the element substrate, an insulating layer 2 formed on the lower electrode 1, and an insulating layer 2 The upper electrode 3 is formed by the insulating layer 2 and is insulated from the lower electrode 1 by the insulating layer 2, and the cantilever portion 7. One end of the cantilever part 7 is supported on the insulating layer 2 and electrically connected to the upper electrode or the lower electrode. The cantilever part 7 comprises a displacement part in the state which other than said one edge part including the other edge part floated from the base material side for elements. The insulating layer 2 is provided with a region where no insulating layer exists (also referred to as “opening”) and a through hole 12. The displacement part of the cantilever part 7 is located on the opening.

2A is a cross-sectional view taken along the line AA ′ in FIG. 1, and FIG. 2B is a cross-sectional view taken along the line BB ′.
3A is a plan view of the cantilever portion 7 as viewed from above, and FIG. 3B is a cross-sectional view taken along the dotted line in FIG.

  As shown in FIG. 3, the cantilever part 7 has a laminated structure of a second conductive layer 71, a piezoelectric material layer 72, and a first conductive layer 73. When the piezoelectric material layer 72 is sandwiched between two conductive layers (71, 73) from above and below to operate the piezoelectric material as a sensor material, the voltage generated by the piezoelectric material is used for the upper and lower conductive layers. Can be detected. Also when used as a vibration element, a voltage can be applied to the piezoelectric material layer from the upper and lower conductive layers.

  As shown in FIG. 2A, the cantilever portion 7 (second conductive layer 71, piezoelectric material layer 72, first conductive layer 73) floats from the element substrate side in the cross section taken along the line AA ′. In this state, the air layer is located between the insulating layer 2 and the air layer. An upper electrode connection line 13 extending from the upper electrode is located on the first conductive layer, and the first conductive layer is conductively connected to the upper electrode 3 through the upper electrode connection line 13.

  As shown in FIG. 2B, the cantilever portion 7 (second conductive layer 71, piezoelectric material layer 72, first conductive layer 73) is fixed to the element substrate side in the cross section taken along line BB ′. In this state, the cantilever portion 7 (71, 72, 73) is positioned on the lower electrode connection line 11 provided on the insulating layer 2 on the lower electrode 1. The second conductive layer 71 is connected to the lower electrode 1 via the lower electrode connection line 11 on the insulating layer 2 and the conductor in the through hole 12 (a part of the lower electrode connection line may also be used). Conductive connection is made.

  Known materials can be used for the material of the lower electrode, the insulating layer, and the upper electrode, respectively. As described above, the material of the cantilever part is not particularly limited as long as any one or more of the conductive layer and the piezoelectric material layer is a resin-containing layer. The resin material can be appropriately selected depending on the purpose and production convenience. For example, phenol resin, melamine resin, polyester resin, furan resin, epoxy resin, polyurethane resin, allyl resin, polyimide resin, silicone resin, ABS resin, acrylic resin, novolac Examples thereof include resin, polystyrene, polyethylene, polybutylene, and fluororesin. Depending on the purpose, functional particles may be dispersed in these resin materials. For example, in the case of imparting conductivity, particles such as gold, silver, copper, and aluminum may be dispersed. Examples of the resin used as the piezoelectric material layer include polyvinylidene fluoride, and polyvinylidene fluoride and polytetrafluoroethylene. In addition, piezoelectric functional particles may be dispersed in other resins. Examples of the piezoelectric functional particles include barium titanate, zirconate titanate, lead titanate, potassium niobate, zinc oxide, lithium tantalate, bismuth titanate, and aluminum nitride. As the conductive layer, a resin-containing layer such as a conductive ink containing a resin as described later can be used.

(Second Embodiment)
This embodiment will be described below with reference to FIGS.

  1 and 2 shown in the first embodiment are views of a single cantilever type piezoelectric element, and an array and a matrix can be realized by arranging a plurality of the single portions. By combining a single cantilever piezoelectric element with a passive matrix, a matrix cantilevered piezoelectric cantilever can be formed. The advantage of matrixing is that sensing can be performed while mapping the target, and much more advanced information can be acquired than when supplementing with only one point. In addition, the application of the matrix vibration element is not shown at present, but advanced devices such as the ability to reproduce complex tones that were not possible by driving a microphone matrix that outputs vibration as sound have been realized. it can.

  One or more lower electrode lines (X direction) and one or more upper electrode lines (Y direction) are formed through an insulating layer, and a cantilever portion is arranged at a position where the X direction and the Y direction intersect, Make electrical connections as in the example. The lower electrode 1 (also referred to as a lower electrode line) and the upper electrode 3 (also referred to as an upper electrode line) in FIGS. The non-existing portion of the electrode is formed by opening an insulating layer. In the case of forming a matrix, since the openings are arranged in the insulating layer vertically and horizontally like a mesh, this can be called a mesh-like (network-like) insulating layer. By pulling out the displacement portion of the cantilever portion into the opening of the mesh-like insulating layer, the hollow cantilever portion can be made into a matrix, and the displacement amount can be increased.

  1 and 2, the first conductive layer 73 of the cantilever part is conductively connected to the upper electrode 3 of the passive matrix (via the connection line for the upper electrode), and the second conductive layer 71 of the cantilever part is through-holed. However, a combination of the connections described in the third, fourth, and fifth embodiments may be used.

(Third embodiment)
This embodiment will be described below with reference to FIGS. 4 and 5 can be formed into a matrix in the same manner as in the second embodiment.

  FIG. 4 is a plan view of a modified example of the cantilever piezoelectric element viewed from above the upper electrode side. 5A is a cross-sectional view taken along line A-A ′ of FIG. 4, and FIG. 5B is a cross-sectional view taken along line B-B ′. In the present embodiment, the first conductive layer 73 is connected to the lower electrode 1, and the second conductive layer 71 is connected to the upper electrode.

  As shown in FIG. 5A, the cantilever portion 7 (second conductive layer 71, piezoelectric material layer 72, first conductive layer 73) is fixed to the element substrate side in the cross section taken along line AA ′. In this state, the cantilever portion 7 (71, 72, 73) is positioned on the upper electrode connection line 13 provided on the insulating layer 2. The second conductive layer 71 is conductively connected to the upper electrode 3 through the upper electrode connection line 13.

  As shown in FIG. 5B, the cantilever portion 7 (second conductive layer 71, piezoelectric material layer 72, first conductive layer 73) floats from the element substrate side in the cross section taken along line BB ′. In this state, the air layer is located between the insulating layer 2 and the air layer. The lower electrode connection line 11 extending from the lower electrode is positioned on the first conductive layer 73, and the first conductive layer 73 passes through the lower electrode connection line 11 and passes through the lower electrode 1. Conductive connection is made.

(Fourth embodiment)
This embodiment will be described below with reference to FIGS. 6 and 7 can be matrixed as in the second embodiment.

  FIG. 6 is a plan view of a modified example of the cantilever piezoelectric element viewed from above the upper electrode side. 7A is a cross-sectional view taken along the line A-A ′ of FIG. 6, and FIG. 7B is a cross-sectional view taken along the line B-B ′. In the present embodiment, the cantilever portion 7 is disposed immediately above the through hole, is connected to the second conductive layer 71, and the first conductive layer 73 and the upper electrode 3 are connected.

  As shown in FIG. 7A, the cantilever part 7 (second conductive layer 71, piezoelectric material layer 72, first conductive layer 73) is fixed to the element substrate side in the cross section taken along the line AA ′. And is located on the insulating layer 2. An upper electrode connection line 13 extending from the upper electrode is positioned on the first conductive layer 73, and the first conductive layer 73 is conductively connected to the upper electrode 3 through the upper electrode connection line 13. .

  As shown in FIG. 7B, the cantilever portion 7 (second conductive layer 71, piezoelectric material layer 72, first conductive layer 73) is fixed to the element substrate side in the cross section taken along line BB ′. The cantilever part 7 (71, 72, 73) is positioned on the insulating layer 2 and is connected to the lower electrode connecting line 11 which is a conductive connecting part penetrating the through hole provided in the insulating layer 2. The second conductive layer 71 is conductively connected to the lower electrode 1. When the cantilever piezoelectric element is manufactured by transfer, the lower electrode connection line 11 can be constituted by an adhesive layer / conductive layer described later.

(Fifth embodiment)
This embodiment will be described below with reference to FIGS. 8 and 9 can be matrixed as in the second embodiment.

  FIG. 8 is a plan view of a modified example of the cantilever piezoelectric element viewed from above the upper electrode side. 9A is a cross-sectional view taken along line A-A ′ of FIG. 8, and FIG. 9B is a cross-sectional view taken along line B-B ′. In the present embodiment, the cantilever portion 7 is disposed so as to contact the upper electrode 3 directly, the second conductive layer 71 and the upper electrode 3 are connected, and the first conductive layer 73 and the lower electrode 1 are connected. It is.

  As shown in FIG. 9A, the cantilever portion 7 (second conductive layer 71, piezoelectric material layer 72, first conductive layer 73) floats from the element substrate side in the cross section taken along the line AA ′. In this state, the air layer is located between the insulating layer 2 and the air layer. A lower electrode connection line 11 extending from the lower electrode is positioned on the first conductive layer 73, and the first conductive layer 73 is a through hole opened in the insulating layer 2 through the lower electrode connection line 11. Is electrically conductively connected to the lower electrode 1.

  As shown in FIG. 9B, the cantilever portion 7 (second conductive layer 71, piezoelectric material layer 72, first conductive layer 73) is fixed to the element substrate side in the cross section taken along line BB ′. In this state, the cantilever portion 7 (71, 72, 73) is positioned on the upper electrode 3 provided on the insulating layer 2. The second conductive layer 71 is conductively connected in contact with the upper electrode 3.

(Sixth embodiment)
In the second embodiment, there is no particular limitation on the length (also referred to as “beam” or “beam”) direction of the plurality of cantilevers, but in this embodiment, when the matrix is formed with one axis, that is, A case where the long direction is aligned in one direction when a plurality of cantilever portions are arranged vertically and horizontally will be described.

  FIG. 10 is a diagram schematically showing the cantilever piezoelectric element 7 having the basic structure shown in the first embodiment in a matrix form. FIG. 10 is a top view of a basic structure in which the basic structure is arranged in the X direction and the Y direction to form a matrix. In FIG. 10, one or more linear lower electrodes 1 (X direction) and one or more linear upper electrodes 3 (Y direction) are formed on a substrate (not shown) with an insulating layer 2 interposed therebetween. A cantilever portion 7 is disposed in the vicinity of the intersection of the upper electrode and the upper electrode. Each of the first conductive layers 73 of the arranged cantilevers 7 is electrically connected to each of the linear upper electrodes 3 arranged in parallel by the upper electrode connection lines. Each of the second conductive layers 71 of the arranged cantilevers 7 is electrically connected to one linear lower electrode 3 by each lower electrode connection line.

(Seventh embodiment)
In the present embodiment, a case where a multi-axis matrix is formed, that is, a case where a plurality of cantilevers are arranged vertically and horizontally, the longitudinal direction is aligned in two or more directions will be described. For example, the longitudinal direction can be arranged in two orthogonal directions (two orthogonal axial directions).

  FIG. 11 is a diagram schematically showing a two-axis correspondence matrix in which the cantilever portions 7 are multi-axially formed into a matrix, and is a plan view seen from the upper electrode side. In FIG. 11, the beam directions of the cantilever portions are aligned in a plurality of directions. In FIG. 11, the basic structure shown in FIG. 1 and the structure shown in FIG. 8 are arranged in parallel in the X direction and the Y direction, and at this time, the beam directions of the cantilever portions in adjacent rows are orthogonal to each other. Are arranged in a matrix. Compared to FIG. 10, FIG. 11 is made to correspond to multiple axes by adding a cantilever portion whose direction is changed to the array. In FIG. 11, one or more linear lower electrodes 1 (X direction) and one or more linear upper electrodes 3 (Y direction) are formed on a substrate (not shown) with an insulating layer 2 interposed therebetween. A cantilever portion 7 is disposed in the vicinity of the intersection of the upper electrode and the upper electrode. Each of the arranged cantilever portions 7 is electrically connected to the upper electrode and the lower electrode, respectively, as shown in FIGS.

  In FIG. 11, the cantilever portions facing in the X direction and the Y direction are alternately arranged, but the combination of the arrangements is not limited to this. In addition, the angle formed by the beam direction of the cantilever portion can be appropriately designed according to the purpose of the sensor.

(Eighth embodiment)
In the present embodiment, the basic structure of the piezoelectric element shown in the first embodiment and the case where the piezoelectric element is used as a sensor or a vibration element will be described along with a concrete example actually manufactured.

  A first electrode (corresponding to a lower electrode), a mesh-like insulating layer partially overlapping on the first electrode, and a part of the first electrode are laminated on the element base material, and the insulation A second electrode (corresponding to the upper electrode) that is insulated through the layer is formed. On the other hand, a first conductive layer is formed on a low surface energy material provided on the surface of the transfer substrate, a piezoelectric material layer covering the first conductive layer is formed, and a resin is formed on the piezoelectric material layer. A second conductive layer containing is formed by a solution process. In a state where the second conductive layer is not completely cured, a part of the second conductive layer is brought into contact with the insulating layer side (including the lower electrode connection line in the case of FIG. 1). The first conductive layer, the piezoelectric material layer, and the second conductive layer are transferred from the low surface energy material to the element substrate side, and [second conductive layer 71 / piezoelectric material layer 72 / first conductive layer 73 are transferred. ] A cantilever part having a structure is formed. In the case of FIG. 1, in a state where the second conductive layer is not completely cured, a part of the second conductive layer mainly contacts the lower electrode connection line and also adheres to the insulating layer.

  The substrate for transfer is not particularly limited as long as the low surface energy material can be uniformly laminated on the surface. Specific examples include metal plates and metal foils made of glass, aluminum, stainless steel, etc., plate-like plastics, thin-film plastic films, paper, and the like.

  The low surface energy material that covers the transfer substrate is preferably a material that easily peels off the ink of the upper layer of the transfer substrate in a later step. Specifically, polydimethylsiloxane and its derivatives and copolymers, resin materials whose terminal groups are fluorine-substituted, such as polytetrafluoroethylene, and surface treatments whose terminal groups are fluorine-substituted, such as fluorinated organopolysiloxanes And surface modifiers such as fluorinated organosilanes and fluorinated alkanethiols.

  The ink containing resin is used for the layer of the cantilever part to be transferred, for example, the second conductive layer because it has a high cohesive force. This is because it is possible to transfer the entire layer including it. When a layer not containing resin is used, only the contact portion is transferred, and the floating portion cannot be formed. Here, the resin is not particularly limited as long as it becomes a film when dried or cured. Examples include polyethylene, polypropylene, polyvinyl alcohol, polystyrene, polyvinyl pyrrolidone, polyvinyl phenol, polyimide, polyamide, polyphthalamide, polyvinyl fluoride, polymethyl methacrylate, polyvinyl chloride, polytetrafluoroethylene, and polyvinylidene fluoride. Epoxy resin, acrylic resin, urethane resin, silicone resin, butyl rubber, isoprene rubber, butadiene rubber, styrene butadiene rubber, natural rubber, and the like. These listed resins are all insulating (dielectric) materials, but may be conductive or semiconductive resins. Examples of the conductive material include PEDOT and PEDOT / PSS, and examples of the semiconductor material include polythiophene and derivatives thereof. These resin materials may be used alone or a plurality of types may be mixed.

  Ink can be mixed with gold, silver, copper, aluminum, nickel, silicon (silicon), silicon carbide, carbon nanotube, graphene, ITO, IZO, etc., in order to develop conductivity.

  In the step of forming the resin-containing layer, the resin-containing layer can be formed by drying or curing the coating layer of the ink containing the resin. The resin-containing layer can also be referred to as, for example, a resin film, and the liquid ink is dissolved or dispersed in a solvent so that the liquid ink becomes a solid by removing the solvent by drying. Point. At this time, the resin polymerization reaction or condensation reaction may not be completely completed. This includes cases where polymerization or condensation treatment (exposure, etc.) is performed later.

  In the transferring step, the entire cantilever part including the resin-containing layer is peeled off from the surface of the low surface energy material on the surface of the transfer substrate. The insulating layer on the cantilever part and the element substrate side (in the case of FIG. 1) This is because the adhesive force formed with the lower electrode connecting line is larger than the adhesive force formed between the low surface energy material and the cantilever part. By using the transfer method, a configuration of a cantilever piezoelectric element and a matrix structure can be efficiently manufactured without using a vacuum apparatus and without using a sacrificial layer in the process. In addition, the method of the present embodiment can be applied to a large transfer apparatus and can easily increase the area.

  Examples will be described in detail below.

<Formation of lower electrode>
Glass is used as a substrate, Ag is formed on the surface of the glass by a 200 nm sputtering method, Ag is formed by a photolithography method, and a line having a width of 500 μm and a length of 100 mm is parallel to the longitudinal direction of the wire at a pitch of 5 mm. The lower electrode was formed by patterning into a shape in which 10 lines were arranged.

<Formation of insulating layer>
On the substrate on which the lower electrode is formed, SU-8 (Nippon Explosives), which is a negative photoresist, is formed by spin coating, patterned by photolithography, and covers all the lines of the lower electrode; Ten lower electrode covered wires (constituting a part of the insulating layer) having a width of 700 μm and 500 μm square through holes formed at intervals of 5 mm on the covered surface were formed. Furthermore, an insulating layer composed of 10 wires in which 10 wires having a width of 700 μm and a length of 100 mm orthogonal to the lower electrode covering wire are arranged at a pitch of 5 mm (hereinafter referred to as “orthogonal insulating layer wire”). To a thickness of 200 μm. The lower electrode covered wire and the orthogonal insulating layer wire constitute a mesh-like insulating layer.

<Formation of connecting wire for lower electrode>
For the lower electrode, nano-Ag ink (Sigma Aldrich 809462) is patterned by the nozzle jet method on the substrate on which the insulating layer is formed, and the conduction of the lower electrode is drawn out from all through holes in the insulating layer to the surface of the insulating layer. A connecting line was formed and baked in an oven at 180 ° C. for 1 hour. The number of lower electrode connection lines formed on the substrate was 100.

<Formation of upper electrode>
On the substrate on which the insulating layer is formed, Au is sputtered to a thickness of 100 nm, and a line having a width of 500 μm and a length of 100 mm is formed on the surface of all lines perpendicular to the lower electrode of the mesh-like insulating layer by photolithography. To form an upper electrode.

<Formation of cantilever part>
Polydimethylsiloxane (PDMS) (Shin-Etsu Silicone Co., KE106), which is a low surface energy material, was applied to a 50 μm thick polyethylene naphthalate film (PEN film) (Teijin DuPont, Q65HA) and cured. Conductive carbon paste (Jujo Chemical Co., Ltd., JELCON CH-8) is screen-printed on the surface to form 100 rectangles with a width and depth of 100 μm and 2 mm, respectively, with a pitch of 5 mm in each of the X and Y directions. And heated in an oven at 150 ° C. for 30 minutes to form a first conductive layer having a thickness of 10 μm. The surface of the first conductive layer is flexographically printed with a polyvinylidene fluoride-tetrafluoroethylene copolymer (Kureha Chemical Co., Ltd.) dissolved in cyclohexanone (Kanto Chemical Co., Ltd.) at 10 wt%, each having a width and depth of 150 μm, A 2.05 mm piezoelectric material layer was formed in the same arrangement so as to cover the first conductive layer, and heated in an oven at 150 ° C. for 30 minutes to form a piezoelectric material layer having a thickness of 10 μm. On the surface of the piezoelectric material layer, a second conductive layer having the same material and shape as the first conductive layer is screen-printed in the same arrangement so as to overlap the first conductive layer. A conductive layer was formed. After the second conductive layer is heated in an oven at 120 ° C. for 5 minutes to be in a semi-dry state, the surface of the PEN film on which each layer is formed and the surface of the insulating layer on the substrate are in contact with each other, and the lower electrode The connecting wire and the second conductive layer were pressed so as to be aligned with each other. Thereby, on the surface of the mesh-like insulating layer having the opening corresponding to the mesh, the cantilever is fixed to the lower electrode connecting line and the floating portion is formed in the opening of the insulating layer with a length of 1.3 mm. The structure [second conductive layer 71 / piezoelectric material layer 72 / first conductive layer 73] was formed. From observation of a three-dimensional shape using a laser microscope (Keyence VK-X120), it was confirmed that a 195 μm air gap was formed between the floating floating portion and the substrate. In order to cure the semiconductive second conductive layer in this state, it was heated in an oven at 150 ° C. for 30 minutes.

<Formation of connection line for upper electrode>
Next, the nano Ag ink is patterned on the substrate by the nozzle jet method to form the upper electrode connection line 13 connecting the surface of the transferred cantilever portion 7 and the upper electrode 3, and baked in an oven at 180 ° C. for 1 hour. . The number of upper electrode connection lines formed on the substrate was 100. As a result, the basic structure of the cantilever shown in FIGS. 1 to 3 was arranged in the XY direction at a pitch of 5 mm, and a matrix of 100 cantilever piezoelectric elements was formed on the entire surface of the substrate.

<Evaluation as tactile sensor>
An FPC was connected to the manufactured substrate having a matrix structure of cantilever piezoelectric elements so as to be connected to the ends of the upper electrode and the lower electrode, and the driver circuit and the measurement PC were connected via the FPC. As a result, a measurement system capable of measuring a voltage generated between the first conductive layer and the second conductive layer of each cantilever type piezoelectric element formed into a matrix was assembled. In this state, when a rubber ball having a diameter of 3 cm was bounced on the matrix, only two elements in the XY direction of the matrix arranged in a sense of 5 mm generated a voltage of 0.5V. Thereby, it was found that the contact area by the movement of the ball was about 1 cm.

<Evaluation as vibration element>
An FPC is connected to the manufactured substrate having a matrix structure of a cantilever type piezoelectric element so as to be connected to the ends of the upper electrode and the lower electrode, and a pulse generator (Tektronix) for generating a frequency and a power source via the FPC It was connected to a source meter (Tektronix) for supply. In this state, when an AC voltage of 50 V is applied between all the upper electrodes and the lower electrodes at a frequency of 100 kHz, the AC voltage generated between the first conductive layer 73 and the second conductive layer 71 of the cantilever part is used. The cantilever vibrated and a sound of 20 dB was generated with a sound meter (Smart Tools).

(Ninth embodiment)
In the present embodiment, a case where the structure of the cantilever piezoelectric element shown in the fourth embodiment (see FIGS. 6 and 7) is used as a sensor or a vibration element will be described along a concrete example actually manufactured.

  Similarly to the eighth embodiment, the element base material includes a first electrode (corresponding to a lower electrode), a mesh-like insulating layer partially overlapping the first electrode, and the first electrode. And a second electrode (corresponding to the upper electrode) insulated from each other through the insulating layer. On the other hand, a first conductive layer is formed on a low surface energy material provided on the surface of the transfer substrate, a piezoelectric material layer covering the conductive layer is formed, and a second conductive layer is formed on the piezoelectric material layer. Layers are formed. For example, the second conductive layer is formed of a layer containing a resin. An adhesive layer / conductive layer containing a resin is formed on part of the second conductive layer. With the adhesive layer / conductive layer not completely cured, the adhesive layer / conductive layer is aligned with the through hole, and the adhesive layer / conductive layer is in contact with the insulating layer and the lower electrode on the element substrate. Thus, the first conductive layer, the piezoelectric material layer, and the second conductive layer are transferred from the low surface energy material to the element substrate side, and [second conductive layer 71 / piezoelectric material layer 72 / second 1 conductive layer 73] to form a cantilever portion.

  As the adhesive layer / conductive layer, it is possible to use a wide range of commonly used adhesive materials that have been imparted with conductivity, such as an insulating layer on the cantilever portion and the element substrate of the present embodiment, There is no particular limitation as long as it can appropriately join the lower electrode and the like. Specific examples include water-soluble adhesives such as vinyl acetate emulsion, rubber adhesives such as nitrile rubber, epoxy adhesives, acrylic adhesives, vinyl adhesives, silicone rubber adhesives, ABS resins, and polycarbonates. Resin adhesives such as polyamide and acrylic. In addition, a conductive adhesive (eg, Fujikura Kasei Co., Ltd. Dotite FA-705BN) or the like can also be used.

  Examples will be described in detail below.

<Formation of the lower electrode> was performed in the same manner as in the eighth embodiment.
<Formation of insulating layer> was performed in the same manner as in the eighth embodiment except that the thickness of the insulating layer was 100 μm.
<Formation of the upper electrode> was performed in the same manner as in the eighth embodiment. Unlike the eighth embodiment, the lower electrode connection line was not formed.

<Formation of cantilever part>
Polydimethylsiloxane (PDMS) (Shin-Etsu Silicone Co., KE106), which is a low surface energy material, was applied to a 50 μm thick polyethylene naphthalate film (PEN film) (Teijin DuPont, Q65HA) and cured. Conductive carbon paste (Jujo Chemical Co., Ltd., JELCON CH-8) is screen-printed on the surface to form 100 rectangles with a width and depth of 100 μm and 2 mm, respectively, with a pitch of 5 mm in each of the X and Y directions. And heated in an oven at 150 ° C. for 30 minutes to form a first conductive layer having a thickness of 10 μm. The surface of the first conductive layer is flexographically printed with a polyvinylidene fluoride-tetrafluoroethylene copolymer (Kureha Chemical Co., Ltd.) dissolved in cyclohexanone (Kanto Chemical Co., Ltd.) at 10 wt%, each having a width and depth of 150 μm, A piezoelectric material layer having a thickness of 2.05 mm was formed in the same arrangement so as to cover the first conductive layer, and heated in an oven at 150 ° C. for 30 minutes to form a piezoelectric material layer having a thickness of 10 μm. On the surface of the piezoelectric material layer, a second conductive layer having the same material and shape as the first conductive layer is screen-printed in the same arrangement so as to overlap the first conductive layer. A layer was formed. This second conductive layer was heated in an oven at 150 ° C. for 30 minutes to be completely cured. Subsequently, a conductive carbon paste having a size of 1 mm square and a thickness of 100 μm was screen-printed at the end of the second conductive layer to form an adhesive layer / conductive layer. This was heated in an oven at 120 ° C. for 5 minutes to make the adhesive layer / conductive layer semi-dry. In this state, the PEN film and the surface of the insulating layer on the substrate were brought into contact with each other so that the adhesive layer / conductive layer overlapped with the through hole of the insulating layer on the substrate. Thereby, on the surface of the mesh-like insulating layer having an opening corresponding to the mesh, it is fixed to the lower electrode connecting line (adhesive layer / conductive layer), and the opening of the insulating layer has a length of 1.3 mm. A cantilever portion with a floating portion is formed, and the through hole is filled with a semi-dried adhesive layer / conductive layer, so that the second conductive layer 71 of the cantilever portion and the lower electrode 1 on the substrate are electrically connected. It was done. From observation of a three-dimensional shape using a laser microscope (Keyence VK-X120), it was confirmed that a 95 μm air gap was formed between the floating portion and the substrate. In order to cure the semiconductive second conductive layer in this state, it was heated in an oven at 150 ° C. for 30 minutes.

<Upper electrode connection line> was performed in the same manner as in the eighth embodiment.
<Evaluation as a tactile sensor> was performed in the same manner as in the eighth embodiment, and similar characteristics were obtained.
<Evaluation as a vibrating element> was performed in the same manner as in the eighth embodiment, and similar characteristics were obtained.

  The examples shown in the above-described embodiment and the like are described for easy understanding of the invention, and are not limited to this embodiment.

  Since the cantilever type piezoelectric element of the present invention can have a large area, a sensor matrix or the like or a vibration element matrix with high resolution and high accuracy can be realized, which is industrially useful. Moreover, since the environmental load can be reduced by the manufacturing method of the present invention, it is industrially useful.

1 Lower electrode (first electrode)
2 Insulating layer 3 Upper electrode (second electrode)
7 Cantilever part 11 Lower electrode connection line 12 Through hole 13 Upper electrode connection line 71 Second conductive layer 72 Piezoelectric material layer 73 First conductive layer

Claims (11)

A first electrode;
An insulating layer comprising an opening and a through hole on the first electrode;
A second electrode partially laminated with the first electrode and insulated by the insulating layer;
A structure comprising a first and second conductive layer and a piezoelectric material layer sandwiched between the conductive layers, and a cantilever portion in which any one or more of the conductive layer and the piezoelectric material layer is a resin-containing layer,
In the cantilever portion, each of the conductive layers is electrically connected to the first electrode or the second electrode directly or through a connection line, and a part of the conductive layer is floated on the opening. A cantilever-type piezoelectric element. When the conductive layer on the side far from the insulating layer is the first conductive layer and the conductive layer on the near side is the second conductive layer,
The first conductive layer is electrically connected to the second electrode through a connection line extending from the second electrode,
The cantilever piezoelectric element according to claim 1, wherein the second conductive layer is electrically connected to the first electrode through the through hole and a connection line. When the conductive layer on the side far from the insulating layer is the first conductive layer and the conductive layer on the near side is the second conductive layer,
The second conductive layer is electrically connected to the second electrode via a connection line extending from the second electrode,
The cantilever piezoelectric element according to claim 1, wherein the first conductive layer is electrically connected to the first electrode through the through hole and a connection line. When the conductive layer on the side far from the insulating layer is the first conductive layer and the conductive layer on the near side is the second conductive layer,
The first conductive layer is electrically connected to the second electrode through a connection line extending from the second electrode,
2. The cantilever piezoelectric element according to claim 1, wherein the second conductive layer is electrically connected to the first electrode through a conductive connection portion in the through hole. When the conductive layer on the side far from the insulating layer is the first conductive layer and the conductive layer on the near side is the second conductive layer,
The second conductive layer is electrically connected directly to the second electrode;
2. The cantilever piezoelectric element according to claim 1, wherein the first conductive layer is electrically connected to the first electrode through a through hole and a connection line.   The first electrode and the second electrode have a matrix structure that intersects with the insulating layer interposed therebetween, the cantilever portions are arranged in a plurality of intersecting regions, and the insulating layer has a mesh shape. The cantilever piezoelectric element according to claim 1, wherein the cantilever piezoelectric element is characterized in that: The first electrode and the second electrode have a matrix structure that intersects via the insulating layer, the cantilever portions are arranged in a plurality of the intersecting regions, and the insulating layer is mesh-shaped,
6. The cantilever piezoelectric element according to claim 1, wherein the plurality of cantilever portions in the intersecting region are arranged in one or more axial directions in the longitudinal direction.   A sensor comprising the cantilever piezoelectric element according to claim 1.   A vibration element comprising the cantilever piezoelectric element according to claim 1. Formed on a substrate for an element are a first electrode, an insulating layer having an opening and a through hole, and a second electrode that is partially laminated with the first electrode and insulated through the insulating layer And
A first conductive layer and a piezoelectric material layer are sequentially formed on the low surface energy material on the surface of the transfer substrate, and a second conductive layer containing a resin is formed on the piezoelectric material layer by a solution process.
By bringing the second conductive layer into contact with the insulating layer side of the element base material in a state where the second conductive layer is not completely cured, the first conductive layer and the piezoelectric material are brought into contact with each other. 2. The method of manufacturing a cantilever piezoelectric element according to claim 1, wherein the layer and the second conductive layer are transferred from the low surface energy material to the element substrate side to form a cantilever part. Formed on a substrate for an element are a first electrode, an insulating layer having an opening and a through hole, and a second electrode that is partially laminated with the first electrode and insulated through the insulating layer And
A first conductive layer, a piezoelectric material layer, and a second conductive layer are sequentially formed on a low surface energy material provided on the surface of the transfer substrate, and a resin is formed on a part of the second conductive layer. Forming an adhesive layer / conductive layer containing
The first conductive layer, the piezoelectric material layer, and the second conductive layer are brought into contact with the insulating layer side of the element base material in a state where the adhesive layer / conductive layer is not completely cured. 2. The method of manufacturing a cantilever piezoelectric element according to claim 1, wherein the cantilever part is formed by transferring the material from the low surface energy material to the element substrate side.

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