JP2012253868A - Electrostatic conversion device and method of manufacturing electrostatic conversion device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electrostatic conversion device and a method of manufacturing the same capable of increasing a power generation amount.SOLUTION: A plurality of moving members 45 are provided. By limiting the area of each of moving members 45 to be such a value as no deflection occurs, the total area of the moving members 45 can be larger. Consequently, the number of moving electrodes 46a-46c can be increased so that a power generation amount is increased.

Description

  The present invention relates to an electrostatic conversion device that converts vibration energy into electrical energy.

  In recent years, development of a ubiquitous network composed of a large number of mobile terminal devices has progressed. In this ubiquitous network, it is desired that the mobile terminal device as a node is small and does not require maintenance from the viewpoint of portability and the like (see, for example, Non-Patent Document 1). However, primary batteries and secondary batteries that have been used for the power source of portable terminal devices are larger in size than other components of portable terminal devices, and maintenance such as replacement and charging is indispensable. .

  Therefore, in recent years, means using the energy harvesting technique has attracted attention as a power source suitable for portable terminal devices. This energy harvesting technology is a technology that converts various kinds of energy normally discharged in vain, such as vibration, heat, and electromagnetic waves (light and radio waves) present in the environment, into electrical energy. Among such energy harvesting techniques, techniques using electromagnetic induction, piezoelectric conversion, electrostatic conversion, and the like have been proposed as techniques for converting vibration energy into electrical energy (see Non-Patent Document 2). In particular, the technology using electrostatic conversion can be easily reduced in size by a semiconductor process or a micro electro mechanical system (MEMS) process, and mechanical elements and electrical elements can be designed and manufactured independently. Therefore, many proposals have been made. An example is shown in FIG. 12 (see Non-Patent Document 3).

  As shown in FIG. 12, the electrostatic conversion device disclosed in Non-Patent Document 3 includes a vibration stage 1010, a lower substrate 1020 made of a silicon substrate provided on the vibration stage 1010, and the lower substrate 1020. And an upper substrate 1030 disposed above the lower substrate 1020 at a predetermined distance, a charging insulating film 1040 provided on the upper substrate 1030, and provided on the charging insulating film 1040. The metal plate 1050 is provided. Here, the charging insulating film 1040 functions as an insulator for holding electric charge, generally called “electret”.

The lower substrate 1020 includes a support member (not shown) erected from the upper surface of the lower substrate 1020, a spring member (not shown) having one end connected to the support member, and the other end of the spring member. A movable member 1021 supported so as to be movable in the plane direction of the substrate 1020, a plurality of movable electrodes 1022 provided on the upper surface of the movable member 1021 at a predetermined interval, and a support member, a spring member, and the movable member 1021 are surrounded. A first spacer member 1023 provided on the upper surface of the lower substrate 1002 is formed. Further, a first pad 1024 connected to the movable electrode 1022 and a second pad 1025 connected to a fixed electrode 1031 described later are provided on the outer edge portion of the upper surface of the lower substrate 1020.
The upper substrate 1030 is provided with a fixed electrode 1031 disposed opposite to the movable electrode 1022 on the lower surface thereof and a position facing the first spacer member 1023 on the lower surface of the upper substrate 1030, and the first spacer member A second spacer member 1032 is provided which is connected to 1023 to separate the lower substrate 1020 and the upper substrate 1030 from each other by a predetermined distance.
Here, the movable electrode 1022 and the fixed electrode 1031 are spaced apart by about 10 μm.

  Such an electrostatic conversion device is manufactured by depositing a thin film by a known MEMS technique.

  The electrostatic conversion device shown in FIG. 12 moves the movable electrode 1022 to alternately generate induced charges in the movable electrode 1022 and the fixed electrode 1031 by an electrostatic field formed by the charging insulating film 1040 functioning as an electret. The vibration energy is converted into electric energy. Specifically, the vibration stage 1010, the second pad 1025, the metal plate 1050, and the external load 1060 are grounded, and the vibration stage 1010 is driven in a state where the first pad 1024 is connected to the external load 1060. Then, the lower substrate 1020 disposed on the vibration stage 1010 and the upper substrate 1030 disposed to face the lower substrate 1020 move in the plane direction, and the movable electrode 1022 is moved to the fixed electrode 1031 along with the movement. Move relatively in the plane direction. Thereby, in the movable electrode 1022 and the fixed electrode 1031, a state in which they are opposed and a state in which they are not opposed are repeatedly generated.

  At this time, in the state where the movable electrode 1022 and the fixed electrode 1031 are opposed to each other, the influence of the electrostatic field formed by the charging insulating film 1040 is shielded by the fixed electrode 1031, so that no positive charge appears on the movable electrode 1022. A positive charge appears on the fixed electrode 1031. From this state, when the movable electrode 1022 and the fixed electrode 1031 are not opposed to each other, that is, the region between the movable electrode 1022 and the adjacent fixed electrode 1031 is opposed, the movable electrode 1022 is moved from the region. It is affected by the electrostatic field formed by the leaked charged insulating film 1040. Then, the positive charge induced by the region moves from the fixed electrode 1031 to the movable electrode 1022 through the external load 1060. By repeating such positive charge movement, an alternating current flows through the external load 1060.

  As described above, the electrostatic conversion device generates electric current by moving electric charges between the movable electrode 1022 and the fixed electrode 1031. Therefore, in order to increase the power generation amount, for example, it is conceivable to increase the number of these electrodes. This can be realized by increasing the areas of the lower substrate 1020, the upper substrate 1030, and the movable member 1021.

T. Shimamura, et al., “Nano-Watt Power Management and Vibration Sensing on a Dust-Size Batteryless Sensor Node for Ambient Intelligence Applications”, Proc. Int. Conf. ISSCC2010, pp. 504-506, 2010 S. Beeby, et al., “Energy harvesting vibration sources for microsystem applications” Meas. Sci. Technol., 17 (2006) pp. R175-R195 N. Sato, K. Ono, T. Shimamura, K. Kuwabara, M. Ugajin, S. Mutoh, H. Morimura, H. Ishii, J. Kodate, and Y. Sato, “Energy Harvesting by MEMS Vibrational Devices with Electrets ”, Digest Tech. Papers, Transducers'09 Conference, Denver, USA, June 21-25, 2009, pp.1381-1384

  However, since the movable member 1021 is formed by depositing a thin film as described above, warping increases when the area is increased. When the warp of the movable member 1021 increases as described above, the distance between the movable electrode 1022 and the fixed electrode 1031 is set to about 10 μm, so that the movable electrode 1022 and the fixed electrode 1031 come into contact with each other, and the horizontal direction of the movable member 1021 Will be hindered. Then, rather than increasing the amount of power generation, even power generation cannot be performed.

  Therefore, an object of the present invention is to provide an electrostatic conversion device and a method for manufacturing the electrostatic conversion device that can increase the amount of power generation.

  In order to solve the above-described problems, an electrostatic conversion device according to the present invention is provided on a first substrate and above the first substrate, and is parallel to the plane of the first substrate. A movable member supported so as to be movable in the first direction, a first electrode provided on the movable member, a first substrate spaced above the movable member by a predetermined distance, and the first substrate A second substrate disposed in parallel with each other, a second electrode provided on a lower surface of the second substrate, disposed opposite to the first electrode at a predetermined interval, and a second substrate An electrostatic conversion device including a charged body provided on an upper surface, wherein a plurality of movable members are provided apart from each other.

  The electrostatic conversion device may further include a connecting member that connects a plurality of movable members.

  In the electrostatic conversion device, the connecting member may be formed in a bar shape extending in the first direction, and the plurality of movable members may be connected along the first direction.

  In the electrostatic conversion device, the connecting member may be formed of an elastic member.

  The electrostatic conversion device may further include a wall member arranged to face the movable member in the first direction.

  The method for manufacturing an electrostatic conversion device according to the present invention includes a first substrate and a first substrate that is provided above the first substrate and moves in a first direction parallel to the plane of the first substrate. A movable member that is supported, a first electrode provided on the movable member, a predetermined distance apart from the movable member above the movable member, and disposed in parallel with the first substrate. A second substrate, a second electrode provided on the lower surface of the second substrate, and opposed to the first electrode at a predetermined distance, and a charged body provided on the upper surface of the second substrate A plurality of movable members spaced apart from each other, and a first method of preparing a silicon substrate having a first insulating film formed on an upper surface as a first substrate. Applying a photoresist on the first insulating film, and applying a predetermined amount to the photoresist; A second step of forming a first resist pattern in which a first opening is formed at a predetermined position by exposure using a mask pattern having a shape; and depositing metal in the first opening by plating. Then, after forming the first metal pattern, the third step of removing the first resist pattern, and the first step of exposing the upper surface of the first metal pattern on the insulating film including the first metal pattern A fourth step of forming a first sacrificial layer; and applying a photoresist on the first sacrificial layer and exposing the photoresist using a mask pattern having a predetermined shape; A second step of forming a second resist pattern in which two openings are formed; and a metal is deposited in the second opening by plating to form a second metal pattern, and then the second resist By removing the turn, a sixth step of forming the movable member, and a second sacrificial layer with the upper surface of the second metal pattern exposed on the second sacrificial layer including the second metal pattern A third opening is formed at a predetermined position by applying a photoresist on the seventh step to be formed and the second sacrificial layer and exposing the photoresist using a mask pattern having a predetermined shape. Eighth step of forming the formed third resist pattern, and depositing metal in the third opening by plating to form the second metal pattern, and then removing the third resist pattern The ninth step of forming the first electrode by the tenth step, the tenth step of removing the first sacrificial layer and the second sacrificial layer, and the second silicon substrate on which the second insulating film is formed on the second surface. Prepared as a substrate A fourth opening is formed at a predetermined position by applying a photoresist on the second insulating film and exposing the photoresist using a mask pattern having a predetermined shape. A twelfth step of forming the formed fourth resist pattern, and forming a fourth metal pattern by depositing metal in the fourth opening by plating, and then removing the fourth resist pattern , A thirteenth step of forming a second electrode, and a fourteenth step of forming a charged body by applying a dielectric treatment after applying an insulator to the lower surface of the second substrate and curing it by heating. The fifteenth step of disposing the second electrode and the first electrode by disposing the second substrate above the first substrate is provided.

  In the manufacturing method of the electrostatic conversion device, the electrostatic conversion device may further include a connecting member that connects the plurality of movable members, and the sixth step may form the connecting member together with the movable member.

  According to the present invention, it is possible to increase the total area of these movable members by providing a plurality of movable members so that the area of each movable member is small enough to prevent warping. The number of first electrodes can be increased, and as a result, the amount of power generation can be increased.

FIG. 1 is a front view schematically showing a cross-section of the configuration of the electrostatic conversion device according to the embodiment of the present invention. FIG. 2 is a plan view from the II line direction of FIG. 3 is a cross-sectional view taken along line III-III in FIG. FIG. 4 is a plan view from the direction of the line II-II in FIG. FIG. 5 is a cross-sectional view taken along line IV-IV in FIG. FIG. 6 is a diagram for explaining the power generation operation by the electrostatic conversion device according to the embodiment of the present invention. FIG. 7 is a diagram for explaining the power generation operation by the electrostatic conversion device according to the embodiment of the present invention. FIG. 8A is a schematic view for explaining the method for manufacturing the electrostatic transducer according to the embodiment of the present invention. FIG. 8B is a schematic diagram for explaining the method for manufacturing the electrostatic transducer according to the embodiment of the present invention. FIG. 8C is a schematic diagram for explaining the method for manufacturing the electrostatic transducer according to the embodiment of the present invention. FIG. 8D is a schematic view for explaining the method for manufacturing the electrostatic transducer according to the embodiment of the present invention. FIG. 8E is a schematic view for explaining the method for manufacturing the electrostatic transducer according to the embodiment of the present invention. FIG. 8F is a schematic view for explaining the method for manufacturing the electrostatic transducer according to the embodiment of the present invention. FIG. 8G is a schematic view for explaining the method for manufacturing the electrostatic transducer according to the embodiment of the present invention. FIG. 8H is a schematic view for explaining the method for manufacturing the electrostatic transducer according to the embodiment of the present invention. FIG. 8I is a schematic diagram for explaining the method for manufacturing the electrostatic transducer according to the embodiment of the present invention. FIG. 8J is a schematic view for explaining the method for manufacturing the electrostatic transducer according to the embodiment of the present invention. FIG. 9A is a schematic view for explaining the method for manufacturing the electrostatic transducer according to the embodiment of the present invention. FIG. 9B is a schematic view for explaining the method for manufacturing the electrostatic transducer according to the embodiment of the present invention. FIG. 9C is a schematic view for explaining the method for manufacturing the electrostatic transducer according to the embodiment of the present invention. FIG. 9D is a schematic view for explaining the method for manufacturing the electrostatic transducer according to the embodiment of the present invention. FIG. 9E is a schematic view for explaining the method for manufacturing the electrostatic transducer according to the embodiment of the present invention. FIG. 10 is a schematic diagram for explaining a method of manufacturing the electrostatic conversion device according to the embodiment of the present invention. FIG. 11 is a plan view showing a modification of the electrostatic conversion device according to the embodiment of the present invention. FIG. 12 is a diagram schematically illustrating a configuration of a conventional electrostatic conversion device.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

[Configuration of electrostatic conversion device]
As shown in FIGS. 1 to 5, the electrostatic conversion device 1 according to the present embodiment has a substantially rectangular plate shape in plan view, and a first insulating film 21 such as silicon oxide is formed on the upper surface. A semiconductor substrate (hereinafter referred to as “lower substrate”) 2 made of silicon or the like, and a shape equivalent to that of the lower substrate 2, spaced apart from the lower substrate 2 by a predetermined distance and parallel to the lower substrate 2. And a semiconductor substrate (hereinafter referred to as “upper substrate”) 3 made of silicon or the like having a second insulating film 31 made of silicon oxide or the like formed on the lower surface thereof.
Here, the lower substrate 2 has a long side parallel to the plane of the lower substrate 2 and a short side parallel to the plane of the lower substrate 2 (hereinafter referred to as “X direction”). And it shall be arrange | positioned along the 2nd direction (henceforth "Y direction") orthogonal to a 1st direction.

<Configuration of lower substrate>
On the first insulating film 21 of the lower substrate 2, a plurality of movable parts 4 arranged in parallel in the X direction, connecting members 22 a and 22 b that connect these movable parts 4, and each movable part 4 are arranged in the X direction. A pair of wall members 23a, 23b provided so as to be sandwiched from both sides thereof, a first spacer member 24 erected from the vicinity of the edge of the lower substrate 2 so as to surround them, and the first spacer member 24 And a plurality of electrodes 25 provided in a region between the lower substrate 2 and the edge of the lower substrate 2. Here, the movable portion 4, the wall members 23 a and 23 b, and the first spacer member 24 are separated from each other by being spaced apart from each other on the first insulating film 21.

≪Configuration of moving part≫
The movable portion 4 includes three first column members 41 a to 41 c that are provided on the first insulating film 21 at a predetermined interval in the X direction, and the first column member 41 a on the first insulating film 21. Three second column members 42a to 42c that are arranged to face each other in the Y direction on a one-to-one basis with -41c, and a second column that has one end supported by the first column members 41a to 41c and the other end arranged opposite to each other. The first beam members 43a to 43c extending toward the members 42a to 42c and the first column members 41a to 41c having one end supported by the second column members 42a to 42c and the other end arranged opposite to each other. Are connected to the other ends of the second beam members 44a to 44c and the first beam members 43a to 43c and the second beam members 44a to 44c so as to be swingable in the X direction. Movable member 45 and in the X direction on this movable member 45 Constant distance apart from juxtaposed three first electrodes (hereinafter, referred to as "movable electrode".) Composed of a 46a through 46c.
For convenience, a direction perpendicular to the X direction and the Y direction, that is, a direction perpendicular to the plane of the lower substrate 2 is referred to as a “Z direction”. Further, in the X direction, the side from the first column member 41a toward the first column member 41b is defined as a positive side. Similarly, in the Y direction, the direction from the first column members 41a to 41c to the second column members 42a to 42c is defined as the positive side. Similarly, in the Z direction, the side away from the lower substrate 2 is defined as the upper side or the upper side, and the side approaching the lower substrate 2 is defined as the lower side or the lower side.

  The first column members 41 a to 41 c are composed of rod-shaped members made of metal protruding upward from the first insulating film 21. As described above, one end of the first beam member 43a is provided at the upper end of the first column member 41a, one end of the first beam member 43b is provided at the upper end of the first column member 41b, and one end of the first column member 41c is provided. One end of the first beam member 43c is connected to the upper end.

  The second column members 42 a to 42 c are constituted by rod-shaped members made of metal protruding upward from the first insulating film 21. As described above, one end of the second beam member 44a is provided at the upper end of the second column member 42a, one end of the second beam member 44b is provided at the upper end of the second column member 42b, and the second column member 42c is provided. One end of the second beam member 44c is connected to the upper end.

  The 1st beam members 43a-43c are comprised from the rod-shaped member which consists of a metal extended along a Y direction. As described above, one end of the first beam member 43 a is connected to the upper end of the first column member 41 a, and the other end is connected to one side surface of the movable member 45. Similarly, one end of the first beam member 43 b is connected to the upper end of the first column member 41 b, and the other end is connected to one side surface of the movable member 45. Similarly, one end of the first beam member 43 c is connected to the upper end of the first column member 41 c, and the other end is connected to one side surface of the movable member 45.

  The 2nd beam members 44a-44c are comprised from the rod-shaped member which consists of a metal extended along a Y direction. As described above, one end of the second beam member 44 a is connected to the upper end of the second column member 42 a, and the other end is connected to one side surface of the movable member 45. Similarly, one end of the second beam member 44 b is connected to the upper end of the second column member 42 b, and the other end is connected to one side surface of the movable member 45. Similarly, one end of the second beam member 44 c is connected to the upper end of the second column member 42 c, and the other end is connected to one side surface of the movable member 45.

  Such first beam members 43a to 43c and second beam members 44a to 44c are formed to have flexibility in at least the X direction. This can be realized, for example, by forming the thickness to be larger than the width, in other words, the length in the Z direction is larger than the length in the X direction in the cross section in the ZX direction. .

  The movable member 45 is composed of a rectangular parallelepiped member made of metal, and is disposed such that the long sides of the upper surface and the lower surface are along the X direction and the short side is along the Y direction, and the area of the upper surface and the lower surface is a movable electrode. 46a-46c and fixed electrode 32a-32c are formed in the size which does not generate | occur | produce the curvature which contacts. Here, the other end of the first beam members 43a to 43c is connected to the side surface of the movable member 45 that faces the first column members 41a to 41c, and the side surface that faces the second column members 42a to 42c. Are connected to the second beam members 44a to 44c. Accordingly, the movable member 45 is suspended above the lower substrate 2 by the first beam members 43a to 43c and the second beam members 44a to 44c. At this time, since the first beam members 43a to 43c and the second beam members 44a to 44c have flexibility in the X direction as described above, the movable member 45 can swing in the X direction, that is, A reciprocating movement is possible on both positive and negative sides in the X direction. Therefore, when the electrostatic conversion device 1 receives an external force, the movable member 45 moves relative to the lower substrate 2. Further, when the electrostatic conversion device 1 itself vibrates, the movable member 45 reciprocates relative to the lower substrate 2.

  The movable electrodes 46 a to 46 c are made of a rod-shaped member made of a metal extending along the Y direction, and are arranged in parallel on the upper surface of the movable member 45 at a predetermined interval in the X direction.

≪Configuration of connecting member≫
The connecting members 22a and 22b are composed of rod-shaped members made of metal extending in the X direction. The connecting member 22a is connected to the first beam member 43a of the movable part 4 with one end positioned on the most negative side, and the other end is connected to the first beam member 43c of the movable part 4 positioned on the most positive side in the X direction. In addition to being connected, the first beam members 43a to 43c located therebetween are also coupled. Thereby, the 1st beam members 43a-43c of each movable part 4 are connected by the connection member 22a in the X direction. Similarly, the connecting member 22b includes a second beam member 44a of the movable portion 4 having one end positioned on the most negative side, and a second beam of the movable portion 4 having the other end positioned on the most positive side in the X direction. It is connected to the member 44c and is also coupled to the second beam members 44a to 44c located between them. Thereby, the 2nd beam members 44a-44c of each movable part 4 are connected with the X direction by the connection member 22b. Therefore, the movable member 45 of each movable part 4 is connected by the connection members 22a and 22b in a state of being arranged in the X direction via the first beam members 43a to 43c and the second beam members 44a to 44c. Therefore, it is interlocked with the other movable member 45 in the X direction.

≪Configuration of wall members≫
The wall members 23a and 23b are made of a rectangular parallelepiped member made of metal, and are arranged such that the long sides of the upper surface and the lower surface are along the Y-axis direction and the short sides are along the X-axis direction. Such wall members 23 a and 23 b are provided for each movable member 45. Further, the side surface of the wall member 23a located on the positive side in the X direction is disposed opposite to the side surface of the movable member 45 located on the negative side in the X direction. Furthermore, the side surface located on the negative side in the X direction of the wall member 23b is disposed opposite to the side surface located on the positive side in the X direction of the movable member 45.

≪Configuration of spacer member≫
The first spacer member 24 is made of a metal, and is formed of a cylindrical member having a substantially rectangular shape in plan view with a long side in the X direction and a short side in the Y direction.

≪Electrode configuration≫
A plurality of electrodes 25 are juxtaposed in the X direction in a region between both sides of the lower substrate 2 parallel to the X axis and the first spacer member 24.
Such a plurality of electrodes 25 include electrodes 25 a connected to the wall members 23 a and 23 b of the movable portion 4 via wirings 26 a formed inside the lower substrate 2. The electrode 25a is grounded to prevent the wall members 23a and 23b from being charged.
In addition, an electrode 25b connected to the first column member 41b of the movable portion 4 through the wiring 26b formed inside the lower substrate 2 is also included. As described above, the movable members 45 are connected by the connecting members 22a and 22b made of metal. Therefore, the electrode 25b is electrically connected to the movable electrodes 46a to 46c of each movable part 4.
Furthermore, an electrode 25 c connected to the electrode 25 d formed on the first insulating film 21 inside the first spacer member 24 through the wiring 26 c formed inside the lower substrate 2 is also included. The electrode 25d is connected to an electrode 36 of the upper substrate 3 described later.

<Configuration of upper substrate>
On the second insulating film 31 provided on the lower surface of the upper substrate 3, second electrodes (hereinafter referred to as the following) provided on the second insulating film 31 corresponding to the movable electrodes 46 a to 46 c on a one-to-one basis. (Referred to as “fixed electrode”) 32 a to 32 c and a first spacer member 24 having a planar shape equivalent to that of the first spacer member 24, and erected from the vicinity of the edge of the upper substrate 3 so as to surround the fixed electrodes 32 a to 32 c. Two spacer members 33 are provided. Here, the fixed electrodes 32 a to 32 c and the second spacer member 33 are separated from each other by being spaced apart from each other on the second insulating film 31.
In addition, a charging insulating film 34 is provided on the upper surface of the upper substrate 3.

  The fixed electrodes 32a to 32c are each composed of a rod-shaped member made of a metal extending along the Y direction, and are arranged in parallel on the second insulating film 31 with a predetermined spacing in the X direction. Such fixed electrodes 32a to 32c are provided for each of the movable portions 4 disposed to face each other in the Z direction, and are disposed at positions facing the movable electrodes 46a to 46c in a one-to-one relationship with the movable member 45 stopped. Has been. The fixed electrodes 32 a to 32 c are connected to each other by a wiring 35. An electrode 36 is provided at one end of the wiring 35. The electrode 36 is connected to the electrode 25d of the lower substrate 2 described above, for example, by laminating metal patterns by a known MEMS technique as will be described later.

  The second spacer member 33 is made of a metal, and is formed of a cylindrical member having a substantially rectangular shape in plan view with a long side in the X direction and a short side in the Y direction. The lower surface of the second spacer member 33 is joined to the upper surface of the first spacer member 24. For this joining, the second spacer member 33 is covered with an adhesive 33a such as a silver paste.

  The charging insulating film 34 is formed on the upper surface of the upper substrate 3 and functions as an electret that is charged with electrons in advance. As will be described later, this charging is realized by an electron beam method, a liquid contact method, a corona discharge method, or the like.

  In such an electrostatic conversion device 1, the electrode 25c and the electrode 25b are connected to an external load. Thereby, fixed electrode 32a-32c and movable electrode 46a-46c will be electrically connected via the external load.

[Power generation operation of electrostatic conversion device]
Next, with reference to FIG. 6, FIG. 7, the electric power generation operation | movement by the electrostatic conversion apparatus 1 which concerns on this Embodiment is demonstrated. Below, the case where the external load 5 is connected to the electrode 25c and the electrode 25b of the electrostatic transducer 1 will be described as an example.

  First, as shown in FIG. 6, when the movable member 45 is stationary, the movable electrodes 46 a to 46 c and the fixed electrodes 32 a to 32 b are arranged to face each other. In such a state, the fixed electrodes 32a to 32c are affected by the electrostatic field formed by the charging insulating film 34. Therefore, the positive charge corresponding to the negative charge of the charging insulating film 34 is fixed by the electrostatic induction principle. Appears at 32a-32c. On the other hand, no positive charges appear on the movable electrodes 46a to 46c because the fixed electrodes 32a to 32c arranged opposite to each other block the influence of the electrostatic field formed by the charging insulating film 34.

  In such a state, for example, when the electrostatic conversion device 1 is vibrated, the movable member 45 having a mass swings in the X direction. When the movable member 45 moves in the positive direction in the X direction, the movable electrodes 46a to 46c also move in the positive direction in the X direction as shown in FIG. 7, and the influence of the electrostatic field formed by the charging insulating film 34 is affected. Is moved away from the fixed electrodes 32a to 32c that shielded the light. Then, the movable electrodes 46a to 46c face the second insulating film 31 and are affected by the electrostatic field formed by the charging insulating film 34 leaking from this position, so that the charging insulating film 34 is based on the principle of electrostatic induction. A positive charge corresponding to the negative charge appears. This positive charge is obtained by moving the positive charges appearing on the fixed electrodes 32a to 32c in FIG. 6 because the fixed electrodes 32a to 32c and the movable electrodes 46a to 46c are connected via the external load 5. is there.

  As described above, when the movable member 45 swings in the X direction by vibrating the electrostatic conversion device 1, positive charges are alternately induced in the fixed electrodes 32a to 32c and the movable electrodes 46a to 46c. An alternating current flows through the load 5.

[Method for Manufacturing Electrostatic Conversion Device]
Next, an example of a method for manufacturing the electrostatic conversion device according to the present embodiment will be described with reference to FIGS. 8A to 10. 8A to 10, the left diagram shows a cross-sectional view in the ZY plane similar to the case of FIG. 3 or 5, and the right diagram shows a cross-sectional view in the ZX plane similar to that in FIG. 1.

<Manufacturing method of lower substrate>
First, for example, a lower substrate 2 made of silicon having a first insulating film 21 made of silicon oxide formed on the upper surface is prepared. The lower substrate 2 may include a semiconductor integrated circuit including a plurality of transistors, resistors, capacitors, wirings, and the like. In this case, a contact hole for electrical connection with an integrated circuit wiring, a pad wiring, or the like may be formed in a predetermined portion of the first insulating film 21.

  A first seed layer 101 is formed on the first insulating film 21 on the lower substrate 2 as shown in FIG. 8A. The first seed layer 101 can be formed by depositing titanium on the first insulating film 21 and depositing gold on the first insulating film 21 by, for example, sputtering or vapor deposition. In this case, the thickness of titanium may be about 0.1 μm, and the thickness of gold may be about 0.1 μm.

  After the first seed layer 101 is formed, a resist material is applied on the first seed layer 101, and the resist material is exposed to light using a mask having a desired pattern. A resist pattern in which an opening is formed at a desired position on the seed layer 101 is formed. At this time, the first seed layer 101 is exposed from the opening. After such a resist pattern is formed, gold is deposited in the opening of the resist pattern by, for example, plating, and then the resist pattern is removed, so that the first seed layer 101 is formed as shown in FIG. 8B. A columnar first metal pattern 102 protruding upward is formed. At this time, for example, by setting the thickness of the resist material to be applied to about 20 μm and the thickness of the plating film to about 15 μm, the height of the first metal pattern 102 can be formed to about 15 μm.

  After the first metal pattern 102 is formed, the first seed layer 101 is removed by etching using the first metal pattern 102 as a mask. As shown in FIG. 8C, the first metal pattern 102 becomes the first insulating layer. On the film 21, they are separated from each other. Thereby, the lower part of 1st pillar member 41a-41c, the lower part of 2nd pillar member 42a-42c, the lower part of wall member 23a, 23b, the lower part of the 1st spacer member 24, and the electrode 25 are formed. .

  The first seed layer 101 is etched away by, for example, first etching the gold exposed above the first seed layer 101 with wet etching using nitric acid and hydrochloric acid, followed by wet etching. Titanium under the seed layer 101 can be formed by wet etching with an aqueous hydrogen fluoride solution.

  After selectively removing the first seed layer 101 by etching, a first sacrificial layer 103 is formed on the first insulating film 21 as shown in FIG. 8D. At this time, the upper surface of the first metal pattern 102 is exposed to the surface of the first sacrificial layer 103. For such a first sacrificial layer 103, for example, a photosensitive organic resin made of PBO (polybenzoxazole) is applied on the first insulating film 21 to form a coating film, and this coating film is formed by known lithography. It can be formed by patterning with a technique. In the patterning, pre-baking at 120 ° C. is performed for 4 minutes as pre-processing, and heat treatment at 310 ° C. is performed after patterning, so that the organic resin film is thermally cured. As the organic resin, for example, CRC8300 manufactured by Sumitomo Bakelite Co., Ltd. can be used.

  After forming the first sacrificial layer 103, as shown in FIG. 8E, the second seed layer 104 is formed on the first sacrificial layer 103 by a method similar to the method of forming the first seed layer 101 described above. Then, a second metal pattern 105 is formed on the second seed layer 104 by a method similar to the method of forming the first metal pattern 102 described above. Here, when the second metal pattern 105 is formed, for example, the resist pattern serving as a mask may be formed to have a thickness of about 40 μm and a plating thickness of about 25 μm.

  After the second metal pattern 105 is formed, the second seed layer 104 is removed by etching using the second metal pattern 105 as a mask in the same manner as the method in which the first seed layer 101 is removed by etching. As shown in FIG. 5, the second metal patterns 105 are separated from each other on the first sacrificial layer 103. Accordingly, the upper portions of the first column members 41a to 41c, the upper portions of the second column members 42a to 42c, the first beam members 43a to 43c, the second beam members 44a to 44c, the movable member 45, and the connecting member 22a. 22b, upper portions of the wall members 23a and 23b, and an upper portion of the first spacer member 24 are formed.

  After selectively removing the second seed layer 104 by etching, a second sacrificial layer 106 is formed on the first sacrificial layer 103 as shown in FIG. 8G. At this time, the upper surface of the second metal pattern 105 is exposed to the surface of the second sacrificial layer 106. The step of forming the second sacrificial layer 106 can be performed by a method equivalent to the step of forming the first sacrificial layer 103 described above.

  After forming the second sacrificial layer 106, as shown in FIG. 8H, a third seed layer 107 is formed on the second sacrificial layer 106 by a method equivalent to the method of forming the first seed layer 101. Then, the third metal pattern 108 is formed on the third seed layer 107 by a method equivalent to the method in which the first metal pattern 102 and the second metal pattern 105 are formed. Here, when the third metal pattern 108 is formed, the resist pattern serving as a mask may be formed to have a thickness of about 10 μm and a plating thickness of about 5 μm.

  After forming the third metal pattern 108, as shown in FIG. 8I, the third metal pattern 108 is masked by a method equivalent to the method in which the first seed layer 101 and the second seed layer 104 are removed by etching. As a result, the third seed layer 107 is removed. As a result, the third metal pattern 108 is separated on the second sacrificial layer 106. Thereby, the movable electrodes 46a to 46c are formed.

  After selectively removing the third seed layer 107 by etching, the first sacrificial layer 103 and the second sacrificial layer 106 are removed as shown in FIG. 8J. As a result, a space is formed below the second seed layer 104 constituting a part of the movable portion 4. The removal of the first sacrificial layer 103 and the second sacrificial layer 106 can be performed, for example, by causing ozone to act on the first sacrificial layer 103 and the second sacrificial layer 106 using an ozone asher device. .

<Method for manufacturing upper substrate>
Next, for example, an upper substrate 3 made of silicon in which a second insulating film 31 made of silicon oxide is formed on one surface is prepared. Here, the upper substrate 3 may include a semiconductor integrated circuit composed of a plurality of transistors, resistors, capacitors, wirings, and the like. In this case, a contact hole for electrical connection with an integrated circuit wiring, a pad wiring, or the like may be formed in a predetermined portion of the second insulating film 31.

  9A, the fourth seed layer 301 is formed on the second insulating film 31 by a method similar to the method of forming the first seed layer 101 and the like described above. Then, a fourth metal pattern 302 is formed on the fourth seed layer 301 by a method similar to the method of forming the first metal pattern 102 and the like. Here, when the fourth metal pattern 302 is formed, for example, the resist pattern serving as a mask may be formed to have a thickness of about 5 μm and a thickness of the plating of about 1 μm. Thereby, a part of each of the fixed electrodes 32a to 32c and the second spacer member 33 is formed.

  After forming the fourth metal pattern 302, as shown in FIG. 9B, the fifth metal pattern 303 is formed on the fourth metal pattern 302 by the same method as the method of forming the first metal pattern 102 described above. Form. Here, when the fifth metal pattern 303 is formed, for example, the resist pattern serving as a mask may be formed to have a thickness of about 30 μm and a thickness of plating of about 20 μm. Thereby, a part of the second spacer member 33 is formed.

  After the fifth metal pattern 303 is formed, the fourth seed layer is masked by using the fourth metal pattern 302 and the fifth metal pattern 303 as a mask by a method similar to the method in which the first seed layer 101 and the like are removed by etching. 301 is removed by etching so that the fourth metal pattern 302 and the fifth metal pattern 303 are separated from each other on the fourth seed layer 301. Thereby, a part of the second spacer member 33 is formed. Then, a resist 304 for surface protection is applied on the second insulating film 31. As a result, as shown in FIG. 9C, the fourth seed layer 301, the fourth metal pattern 302, and the fifth metal pattern 303 are covered with the resist 304.

  Next, as shown in FIG. 9D, an insulating material is applied to the surface of the upper substrate 3 on the side where the second insulating film 31 is not provided by spin coating or the like, and is cured by heating, thereby charging the insulating film. 34 is formed. Here, the charging insulating film 34 is formed to a thickness of about 20 μm.

  After the charging insulating film 34 is cured by heating, the upper substrate 3 is subjected to a charging process by a known method such as an electron beam method, a liquid contact method, or a corona discharge method. For example, the applied voltage may be −1000 V and the application time may be 60 minutes. By such a charging process, the surface of the insulating film 4 is charged with negative charges.

  Next, as shown in FIG. 9E, after removing the resist 304 with a remover, the upper substrate 3 is washed with water.

<Bonding of lower substrate and upper substrate>
Next, as shown in FIG. 10, the surface of the lower substrate 2 on which the first insulating film 21 is formed and the surface of the upper substrate 3 on which the second insulating film 31 is formed are opposed to each other. The upper surface of the second metal pattern 105 that functions as the first spacer member 24 formed on the lower substrate 2 and the fifth metal pattern 303 that functions as the second spacer member 33 formed on the upper substrate 3. Bond the top surface. As this bonding method, it can be performed by known COC (Chip On Chip) bonding, room temperature SAB (Surface Activated Bonding) bonding, or the like. In the present embodiment, after covering the fourth seed layer 301, the third metal pattern 302, and the fifth metal pattern 303 constituting the second spacer member 33 with the silver paste 305, as described above, The upper surface of the second metal pattern 105 and the upper surface of the fifth metal pattern 303 are bonded together, thereby bonding the lower substrate 2 and the upper substrate 3 together. Thereby, the electrostatic conversion apparatus 1 is completed.

  As described above, according to the present embodiment, by providing a plurality of movable members 45, the area of each movable member 45 is made small enough to prevent warping, so that the total of these movable members 45 can be obtained. Therefore, the number of movable electrodes 46a to 46c can be increased, and as a result, the amount of power generation can be increased.

  Further, according to the present embodiment, by providing the connecting members 22a and 22b that connect the plurality of movable members 45, the plurality of movable members 45 are arranged in the X direction that is the extending direction of the connecting members 22a and 22b. By connecting in a state, the plurality of movable members 45 are simultaneously moved in the same direction, and the plurality of movable electrodes 46a to 46c provided on each movable member 45 and the movable electrodes 46a to 46c are arranged to face each other. Charges move simultaneously with the fixed electrodes 32a to 32c, and as a result, the amount of power generation can be increased.

  Furthermore, according to the present embodiment, by providing the wall members 23a and 23b, the movement amount of the movable member 45 is limited, and the movable member 45 prevents contact with the adjacent movable member 45 and other components. As a result, it is possible to prevent the movable member 45 from being damaged.

  In the present embodiment, the case where the movable member 45 of each movable portion 4 is coupled by the coupling members 22a and 22b has been described as an example, but the movable member 45 is not coupled without providing the coupling members 22a and 22b. It may be. Even if it does in this way, the effect equivalent to this Embodiment can be acquired.

  Moreover, in this Embodiment, although the case where the connection members 22a and 22b were formed in a linear rod was demonstrated to the example, the structure of a connection member is not limited to this, It can set freely suitably. For example, as shown in FIG. 11, connecting members 22 a ′ and 22 b ′ having elastic portions 221 a and 221 b in which a portion between adjacent movable portions 4 has a meander shape may be used. By providing such connecting members 22a 'and 22b', it is possible to set a plurality of resonance frequencies of each movable part 4, so that a multi-mode power generation operation can be realized.

  Further, in the present embodiment, the case where two wall members 23a and 23b are provided for each movable member 45 has been described as an example, but wall members are provided on both the positive and negative sides of the movable member 45 in the X direction. If it is, the quantity of a wall member is not limited to it, It can set freely suitably. For example, only one wall member may be provided between the adjacent movable members 45. Thereby, size reduction is realizable.

  The present invention can be applied to an electrostatic transducer that converts vibration energy into electrical energy.

  DESCRIPTION OF SYMBOLS 1 ... Electrostatic transducer 2, 2 '... Lower substrate, 3 ... Upper substrate, 4 ... Movable part, 21 ... 1st insulating film, 22a, 22b, 22a', 22b '... Connection member, 23a, 23b ... Wall member, 24 ... first spacer member, 25, 25a-25c, 26a-26c ... wiring, 36 ... electrode, 31 ... second insulating film, 32a-32c ... fixed electrode, 33 ... second spacer member, 34 ... charging insulating film, 35 ... wiring, 41a-41c ... first pillar member, 42a-42c ... second pillar member, 43a-43c ... first beam member, 44a-44c ... second beam member, 45 ... movable member, 46a to 46c ... movable electrode, 101 ... first seed layer, 102 ... first metal pattern, 103 ... first sacrificial layer, 104 ... second seed layer, 105 ... second metal Pattern, 106 ... second sacrificial layer, 107 ... third sheet Layer, 108 ... third metal pattern, 301 ... fourth seed layer, 302 ... fourth metal patterns, 303 ... fifth metal pattern, 304 ... resist.

Claims (7)

A first substrate;
A movable member provided above the first substrate and supported so as to be movable in a first direction parallel to the first substrate;
A first electrode provided on the movable member;
A second substrate disposed above the movable member and spaced apart from the movable member by a predetermined distance and parallel to the first substrate;
A second electrode provided on the lower surface of the second substrate and disposed opposite to the first electrode at a predetermined interval;
An electrostatic conversion device comprising: a charged body provided on an upper surface of the second substrate;
A plurality of the movable members are provided so as to be separated from each other. The electrostatic conversion device according to claim 1, further comprising a connecting member that connects the plurality of movable members to each other. The electrostatic conversion device according to claim 2, wherein the connecting member is formed in a rod shape extending in the first direction, and connects the plurality of movable members along the first direction. The electrostatic conversion device according to claim 2, wherein the connecting member is made of an elastic member. The electrostatic conversion device according to claim 1, further comprising: a wall member disposed to face the movable member in the first direction. A first substrate, a movable member provided above the first substrate and supported so as to be movable in a first direction parallel to the plane of the first substrate, and provided on the movable member A first substrate formed above, a second substrate disposed above the movable member and spaced apart from the movable member by a predetermined distance and parallel to the first substrate, and the second substrate A second electrode disposed opposite to the first electrode and spaced apart from the first electrode by a predetermined distance; and a charged body provided on the upper surface of the second substrate, wherein the movable members are separated from each other. A plurality of electrostatic conversion device manufacturing methods,
A first step of preparing, as the first substrate, a silicon substrate having a first insulating film formed on an upper surface;
A first resist in which a first opening is formed at a predetermined position by applying a photoresist on the first insulating film and exposing the photoresist using a mask pattern having a predetermined shape. A second step of forming a pattern;
A third step of removing the first resist pattern after depositing a metal in the first opening by plating to form a first metal pattern;
A fourth step of forming a first sacrificial layer exposing an upper surface of the first metal pattern on the insulating film including the first metal pattern;
A second resist in which a second opening is formed at a predetermined position by applying a photoresist on the first sacrificial layer and exposing the photoresist using a mask pattern having a predetermined shape. A fifth step of forming a pattern;
A sixth step of forming the movable member by depositing a metal in the second opening by a plating method to form a second metal pattern and then removing the second resist pattern;
A seventh step of forming a second sacrificial layer in which an upper surface of the second metal pattern is exposed on the second sacrificial layer including the second metal pattern;
A third resist in which a third opening is formed at a predetermined position by applying a photoresist on the second sacrificial layer and exposing the photoresist using a mask pattern having a predetermined shape. An eighth step of forming a pattern;
A ninth step of forming the first electrode by depositing a metal in the third opening by plating to form a second metal pattern and then removing the third resist pattern;
A tenth step of removing the first sacrificial layer and the second sacrificial layer;
An eleventh step of preparing a silicon substrate having a second insulating film formed on the upper surface as the second substrate;
A fourth resist in which a fourth opening is formed at a predetermined position by applying a photoresist on the second insulating film and exposing the photoresist using a mask pattern having a predetermined shape. A twelfth step of forming a pattern;
A thirteenth step of forming the second electrode by depositing metal in the fourth opening by plating to form a fourth metal pattern and then removing the fourth resist pattern; ,
A fourteenth step of forming the charged body by applying an insulating treatment after applying an insulator on the lower surface of the second substrate and heating and curing;
A fifteenth step of disposing the second substrate above the first substrate so that the second electrode and the first electrode are disposed to face each other. A method for manufacturing a conversion device. The electrostatic conversion device further includes a connecting member that connects the plurality of movable members,
The method of manufacturing an electrostatic conversion device according to claim 6, wherein in the sixth step, the connecting member is formed together with the movable member.

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