JP2012095422A - Electrostatic conversion apparatus and method for manufacturing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electrostatic conversion apparatus capable of improving a generating efficiency, and method for manufacturing the same.SOLUTION: A first fixed electrode 17 and a second fixed electrode 18 are arranged on an orbit of an insulating charged body 16 formed on a surface of a wide part 15b to oppose the first fixed electrode 17 and the second fixed electrode 18 to the insulating charged body 16 in a plane perpendicular to a semiconductor substrate 11. An overlap area of the insulating charged body 16, and the first fixed electrode 17 and the second fixed electrode 18 can be set without being restricted by an area of the semiconductor substrate 11, and the generating efficiency can be improved.

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, the primary battery and the secondary battery conventionally used for the power source of the mobile terminal device are larger in size than the components of the mobile terminal device, 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. 16 (see Non-Patent Document 3).

  As shown in FIG. 16, the electrostatic conversion device disclosed in Non-Patent Document 3 is composed of a lower substrate 701 made of a glass plate of about 20 mm square and a material equivalent to the lower substrate 701, and And an exciter 703 that is connected to one end of the upper substrate 702 and vibrates the upper substrate 702 in a direction parallel to the plane. And. A plurality of electrodes 704 are provided on the surface of the lower substrate 701 facing the upper substrate 702. Similarly, a plurality of electrodes 705 are provided on the surface of the upper substrate 702 facing the lower substrate 701. These electrodes 704 and 705 are arranged opposite to each other and are electrically connected via an external load 706. In addition, an insulating layer 707 is provided on a part of the electrode 704 provided on the lower substrate 701. This insulating layer 707 functions as an insulator for retaining electric charge, generally called “electret”.

  In the electrostatic conversion device configured as described above, an induced charge is generated in the electrode 705 facing the insulating layer 707 by an electrostatic field formed by the insulating layer 707 functioning as an electret. Then, the vibrator 703 is driven to vibrate the upper substrate 702 in a direction parallel to the plane, so that the overlapping area (hereinafter referred to as “overlapping area”) of the insulating layer 707 and the electrode 705 is changed. Then, when a portion that does not overlap with the insulating layer 707 of the electrode 705 is generated, the charge induced in this portion moves to the electrode 704 through the external load 706, and when that portion again overlaps with the insulating layer 707, The electric charge that has moved to the electrode 704 moves to that portion through the external load 706. As a result, an alternating current flows to the outside 706. Therefore, the power generation efficiency of such an electrostatic conversion device depends on a change in the overlapping area due to a spatial change in the electric field formed by the electret and a change in the relative positional relationship between the lower substrate 701 and the upper substrate 702. You can say.

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. 504-505, 2010 S. Beeby, et al., “Energy harvesting vibration sources for microsystem applications” Meas. Sci. Technol., 17 (2006) pp. R175-R195 T. Tsutsumino, et al., “SEISMIC POWER GENERATOR USING HIGH-PERFORMANCE POLYMER ELECTRET” Proc. Int. Conf. MEMS 2006, pp. 98-101, 2006

  However, in the conventional electrostatic conversion device, the region where the insulating layer 707 functioning as an electret and the electrode 705 facing the electret can be formed is limited to the facing surface between the lower substrate 701 and the upper substrate 702. For this reason, it has been difficult to improve the power generation efficiency.

  Accordingly, an object of the present invention is to provide an electrostatic conversion device and a method for manufacturing the electrostatic conversion device that can improve power generation efficiency.

  In order to solve the above-described problems, an electrostatic conversion device according to the present invention is provided above a substrate and supported so as to be movable in a first direction parallel to the plane of the substrate. A movable member, a bar-shaped member extending in the first direction, one end of which is connected to the movable member, a first charged body provided at the other end of the arm member, and a substrate A first fixed electrode provided on the substrate and provided at a predetermined distance apart in a second direction parallel to the plane and perpendicular to the first direction from the movement locus of the first charged body; It is provided with the 2nd fixed electrode arranged in parallel with the 1st fixed electrode along the 1st direction.

  The electrostatic conversion device further includes a first terminal and a second terminal connected to an external load, the first terminal is connected to the first fixed electrode, and the second terminal is the first terminal You may make it connect to 2 fixed electrodes.

  In the electrostatic conversion device, the arm member may be provided on both sides of the movable member.

  In the electrostatic conversion device, the first fixed electrode and the second fixed electrode may be provided at positions that are line-symmetric with respect to the movement locus.

  In the electrostatic conversion device, the second fixed electrode may be provided on both sides of the first fixed electrode in the first direction.

  Further, in the electrostatic conversion device, a pair of columnar column members suspended on the substrate at a predetermined interval in the second direction, and one end supported on the upper end of one column member, the other column member The movable member has a rectangular parallelepiped shape, and the other end of the beam member is connected to the pair of first side surfaces facing the column member. By doing so, the arm member may be provided on the second side surface orthogonal to the first side surface of the movable member.

  In the electrostatic conversion device, the second charged body suspended from the upper surface of the movable member, the third fixed electrode disposed opposite to the second charged body above the movable member, and the movable member And a fourth fixed electrode disposed apart from the third fixed electrode in the first direction.

  In the electrostatic conversion device, a plurality of second charged bodies are provided at predetermined intervals in the first direction, and the third fixed electrode and the fourth fixed electrode are alternately arranged in the second direction. A plurality of them may be provided.

  In addition, a method for manufacturing an electrostatic conversion device according to the present invention includes a substrate, a movable member provided above the substrate and supported so as to be movable in a first direction parallel to the plane of the substrate, It consists of a rod-shaped member extending in the first direction, one end of which is connected to the movable member, the first charging body provided at the other end of the arm member, A first fixed electrode provided at a predetermined distance apart in a second direction parallel to the plane and perpendicular to the first direction from the movement locus of the first charged body, and suspended from the substrate; A method of manufacturing an electrostatic conversion device comprising a first fixed electrode and a second fixed electrode arranged in parallel along a first direction, wherein a silicon substrate having an upper surface formed with an insulating film is used as a substrate First step to be prepared, and a photoresist is applied on the insulating film, and a predetermined amount is applied 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. And forming the first metal pattern, and then removing the first resist pattern to form a lower portion of the first fixed electrode and a lower portion of the second fixed electrode, A fourth step of forming a first sacrificial layer with the upper surface of the first metal pattern exposed on an insulating film including the metal pattern; and applying a photoresist on the first sacrificial layer; A fifth step of forming a second resist pattern in which a second opening is formed at a predetermined location by exposing the substrate to light using a mask pattern having a predetermined shape, and a second opening by plating. After the metal is deposited in the part to form the second metal pattern, the second resist pattern is removed, so that the upper part of the first fixed electrode, the upper part of the second fixed electrode, the movable member, and the arm member A sixth step of forming, a seventh step of removing the first sacrificial layer, and an eighth step of forming a first charged body on the arm member by electrodeposition It is.

  According to the present invention, by arranging the first fixed electrode and the second fixed electrode in parallel with the track of the first charging body, the first charging body and the first and second charging bodies are arranged in a plane perpendicular to the substrate. The fixed electrodes are opposed to each other. Accordingly, the overlapping area between the first charged body and the first and second fixed electrodes can be set without being restricted by the area of the substrate, and the power generation efficiency can be improved.

FIG. 1 is a plan view schematically showing the configuration of the electrostatic conversion device according to the first embodiment of the present invention. 2 is a cross-sectional view taken along the line II of FIG. FIG. 3 is an enlarged view of a main part for explaining the operation of the electrostatic conversion device of FIG. FIG. 4 is an enlarged view of a main part for explaining the operation of the electrostatic conversion device of FIG. FIG. 5 is a plan view schematically showing the configuration of the electrostatic conversion device according to the second embodiment of the present invention. 6 is an enlarged view of a main part for explaining the operation of the electrostatic conversion device of FIG. FIG. 7 is a plan view schematically showing the configuration of the electrostatic conversion device according to the third embodiment of the present invention. 8 is a cross-sectional view taken along line II-II in FIG. FIG. 9 is an enlarged view of a main part for explaining the operation of the electrostatic conversion device of FIG. FIG. 10 is an enlarged view of a main part for explaining the operation of the electrostatic conversion device of FIG. FIG. 11 is a plan view schematically showing the configuration of the electrostatic conversion device according to the fourth embodiment of the present invention. 12 is a cross-sectional view taken along line III-III in FIG. 13 is a cross-sectional view taken along line IV-IV in FIG. 14 is a cross-sectional view taken along line VV in FIG. FIG. 15A is a schematic diagram for explaining the manufacturing method for the electrostatic transducer according to the fourth embodiment of the present invention. FIG. 15B is a schematic diagram for explaining the method for manufacturing the electrostatic transducer according to the fourth embodiment of the present invention. FIG. 15C is a schematic diagram for explaining the method for manufacturing the electrostatic transducer according to the fourth embodiment of the present invention. FIG. 15D is a schematic diagram for explaining the method for manufacturing the electrostatic transducer according to the fourth embodiment of the present invention. FIG. 15E is a schematic view for explaining the method for manufacturing the electrostatic transducer according to the fourth embodiment of the present invention. FIG. 15F is a schematic view for explaining the method for manufacturing the electrostatic transducer according to the fourth embodiment of the present invention. FIG. 15G is a schematic view for explaining the method for manufacturing the electrostatic transducer according to the fourth embodiment of the present invention. FIG. 15H is a schematic view for explaining the method for manufacturing the electrostatic transducer according to the fourth embodiment of the present invention. FIG. 15I is a schematic diagram for explaining the manufacturing method for the electrostatic transducer according to the fourth embodiment of the present invention. FIG. 15J is a schematic view for explaining the method for manufacturing the electrostatic transducer according to the fourth embodiment of the present invention. FIG. 15K is a schematic diagram for explaining the manufacturing method for the electrostatic transducer according to the fourth embodiment of the present invention. FIG. 15L is a schematic diagram for explaining the manufacturing method for the electrostatic transducer according to the fourth embodiment of the present invention. FIG. 15M is a schematic diagram for explaining the manufacturing method for the electrostatic transducer according to the fourth embodiment of the present invention. FIG. 15N is a schematic diagram for explaining the manufacturing method for the electrostatic transducer according to the fourth embodiment of the present invention. FIG. 15O is a schematic view for explaining the method for manufacturing the electrostatic transducer according to the fourth embodiment of the present invention. FIG. 15P is a schematic diagram for explaining the manufacturing method for the electrostatic transducer according to the fourth embodiment of the present invention. FIG. 15Q is a schematic diagram for explaining the manufacturing method for the electrostatic transducer according to the fourth embodiment of the present invention. FIG. 15R is a schematic diagram for explaining the manufacturing method for the electrostatic transducer according to the fourth embodiment of the present invention. FIG. 16 is a cross-sectional view schematically showing a configuration of a conventional electrostatic conversion device.

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

[First Embodiment]
First, a first embodiment of the present invention will be described.

<Configuration of electrostatic conversion device>
As shown in FIGS. 1 and 2, the electrostatic conversion device 1 according to the present embodiment includes a semiconductor substrate 11 made of silicon or the like having an insulating film 12 such as silicon oxide formed on the upper surface, and an upper portion of the semiconductor substrate 11. And a movable member 15 supported in a first direction parallel to the plane of the semiconductor substrate 11 (hereinafter referred to as “Y direction”) and movable on the insulating film 12. The first fixed electrode 17 and the second fixed electrode 18 are provided at positions spaced from the 15 in the Y direction. Here, the movable member 15, the first fixed electrode 17, and the second fixed electrode 18 are insulated and separated from each other on the semiconductor substrate 11. In the present embodiment, a plurality of first fixed electrodes 17 and a plurality of second fixed electrodes 18 are provided along the X direction, and are connected to a pair of terminals 20 via wirings 19. Here, the plurality of first fixed electrodes 17 are electrically commonly connected to one terminal 20, and the plurality of second fixed electrodes 18 are electrically commonly connected to the other terminal 20. Yes. This terminal 20 is configured to be connectable to an external load 21.
For convenience, a direction perpendicular to the X direction and the Y direction, that is, a direction perpendicular to the plane of the semiconductor substrate 11 is referred to as a “Z direction”. In the X direction, the side from the column member 13a toward the column member 13b is defined as a positive side. Similarly, in the Y direction, the upper side with respect to the paper surface of FIG. Similarly, in the Z direction, the side away from the semiconductor substrate 11 is defined as the upper side or the upper side, and the side approaching the semiconductor substrate 11 is defined as the lower side or the lower side. Moreover, in FIG. 2, description is abbreviate | omitted except a cut surface.

  The movable member 15 includes a pair of column members 13a and 13b provided on the insulating film 12 at a predetermined interval, one end supported by one column member 13a and 13b, and the other end supported by the other column member 13a and 13b. A pair of beam members 14a, 14b extending toward the end, a movable member 15 supported so as to be swingable in the Y direction by being connected to the other ends of the beam members 14a, 14b, and column members 13a, 13b. And the insulating charged body 16 that covers the surfaces of the beam members 14 a and 14 b and the movable member 15.

  The column members 13a and 13b are composed of rod-shaped members made of metal protruding upward from the insulating film 12. One end of the beam member 14a is connected to the upper end of the column member 13a, and one end of the beam member 14b is connected to the upper end of the column member 13b.

  The beam members 14a and 14b are composed of rod-shaped members made of metal extending along the X direction. As described above, one end of the beam member 14 a is connected to the upper end of the column member 13 a, and the other end is connected to one side surface of the movable member 15. Similarly, one end of the beam member 14 b is connected to the upper end of the column member 13 b, and the other end is connected to one side surface of the movable member 15. Such beam members 14a and 14b are formed to have flexibility in at least the Y 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 Y direction in the cross section in the ZY direction. .

  The movable member 15 is composed of a rectangular parallelepiped member made of metal, and is arranged so that the longitudinal direction of the upper surface and the lower surface is along the X direction, and the lateral direction is along the Y direction. Here, the other end of the beam members 14 a and 14 b facing each other is connected to two side surfaces (hereinafter referred to as “first side surfaces”) facing the column members 13 a and 13 b of the movable member 15. Thereby, the movable member 15 is suspended above the semiconductor substrate 11 by the beam members 14a and 14b. At this time, since the beam members 14a and 14b have flexibility in the Y direction as described above, the movable member 15 can swing in the Y direction and can reciprocate in the positive and negative directions in the Y direction. It is said that. Therefore, when the electrostatic conversion device 1 receives an external force, the movable member 15 moves relative to the semiconductor substrate 11. When the electrostatic conversion device 1 itself vibrates, the movable member 15 reciprocates relative to the semiconductor substrate 11.

On two side surfaces different from the first side surface of the movable member 15 (hereinafter referred to as “second side surface”), a plurality of plate-like arm members 15 a provided vertically along the Y direction are mutually in the X direction. Formed at a predetermined interval. As described above, since the movable member 15 is movable to both positive and negative sides in the Y direction, the arm member 15a also moves to both positive and negative sides in the Y direction as the movable member 15 moves.
An end portion of the arm member 15a opposite to the side connected to the second side surface is provided with a wide portion 15b having a substantially rectangular shape in plan view and having a large length in the X direction. The length of the arm member 15a in the Y direction is set according to the amount of movement of the movable member 15 in the Y direction. That is, the second side surface of the movable member 15 is set so as not to contact the first fixed electrode 17.
Such a movable member 15 is grounded via a wiring (not shown).

  The insulated charging body 16 is composed of insulators formed on the surfaces of the column members 13 a and 13 b, the beam members 14 a and 14 b and the movable member 15. Such an insulating charged body 16 functions as an electret in which at least the wide portion 15b 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.

  The first fixed electrode 17 is composed of a metal columnar member protruding upward from the insulating film 12. Such a first fixed electrode 17 is spaced apart from the second side surface of the movable member 15 by a predetermined distance while the movable member 15 is stationary, and is spaced from the wide portion 15b by a predetermined distance in the X direction. It is arranged. The distance between the wide portion 15b and the first fixed electrode 17 is set to a distance at which the first fixed electrode 17 is affected by the electrostatic field of the insulating charging body 16 provided on the surface of the wide portion 15b. The first fixed electrodes 17 can be associated with one arm member 15a one by one.

  The second fixed electrode 18 is composed of a metal columnar member protruding upward from the insulating film 12, and is disposed on the insulating film 12 at a predetermined distance from the second side surface of the movable member 15. . The second fixed electrode 18 is arranged on the same straight line along the Y direction with the first fixed electrode 17 with a predetermined interval. The second fixed electrode 18 can be associated with one arm member 15a one by one.

<Power generation operation of electrostatic conversion device>
Next, with reference to FIGS. 3 and 4, the power generation operation by the electrostatic conversion device according to the present embodiment will be described.

  First, as shown in FIG. 3, the first fixed electrode 17 located near the wide portion 15b in a state where the movable member 15 is stationary is caused by the insulating charging body 16 provided on the surface of the wide portion 15b. Under the influence of the formed electrostatic field, a positive charge corresponding to the negative charge of the insulating charged body 16 appears on the first fixed electrode 17 by the principle of electrostatic induction.

  In this state, for example, when the electrostatic conversion device 1 is vibrated, the movable member 15 having a mass swings in the Y direction. When the movable member 15 moves in the positive direction in the Y direction, as shown in FIG. 4, the wide portion 15b also moves in the positive direction in the Y direction, moves away from the first fixed electrode 17, and moves to the second fixed electrode. Approach 18 Then, the second fixed electrode 18 is closer to the insulating charging body 16 provided on the surface of the wider portion 15 b than the first fixed electrode 17, so that the insulating charging body 16 is formed more than the first fixed electrode 17. In order to be more strongly affected by the electrostatic field, a positive charge corresponding to the negative charge appears on the second fixed electrode 18 by the principle of electrostatic induction. This positive charge is because the first fixed electrode 17 and the second fixed electrode 18 are electrically connected via the external load 21, and thus the positive charge that appears on the first fixed electrode 17 in FIG. 3. Has been moved.

  When the movable member 15 moves again in the negative direction of the Y direction from the state shown in FIG. 4, the wide portion 15 b moves away from the second fixed electrode 18 and moves to the first fixed electrode 17 as shown in FIG. 3. Get closer. Then, since the first fixed electrode 17 is more strongly affected by the electrostatic field formed by the insulating charged body 16 provided on the surface of the wide portion 15b than the second fixed electrode 18, positive charge is caused by electrostatic induction. Will appear. This positive charge has moved from the second fixed electrode 18.

  Thus, when the movable member 15 swings in the Y direction by vibrating the electrostatic conversion device 1, positive charges are alternately induced in the first fixed electrode 17 and the second fixed electrode 18, A current flows through the external load 21.

  As described above, according to the present embodiment, by arranging the first fixed electrode 17 and the second fixed electrode 18 in parallel with the track of the insulating charging body 16 formed on the surface of the wide portion 15b, Insulating charging body 16, first fixed electrode 17, and second fixed electrode 18 face each other in a plane perpendicular to semiconductor substrate 11. Therefore, it is possible to set the overlapping area between the insulating charged body 16 and the first fixed electrode 17 and the second fixed electrode 18 without being restricted by the area of the semiconductor substrate 11, thereby improving the power generation efficiency. it can.

  In addition, according to the present embodiment, the electrostatic conversion can be performed on the two second side surfaces among the six surfaces forming the surface of the rectangular parallelepiped movable member 15. As a result, the output can be improved and the electrostatic conversion can be performed. Miniaturization of the apparatus can be realized.

  In the present embodiment, as shown in FIG. 1, the case where four arm members 15a are provided for each of the second side surfaces of the movable member 15 has been described as an example. However, the number of arm members 15a is limited to four. Needless to say, it can be set as appropriate.

  Further, in the present embodiment, the case where the wide portion 15b is provided at a position facing the first fixed electrode 17 in the X direction when the movable member 15 is stationary has been described as an example, but the position where the wide portion 15b is provided. Is not limited to this, and can be freely set as appropriate. For example, the wide portion 15b may be provided at a position facing the region between the first fixed electrode 17 and the second fixed electrode 18 in the X direction when the movable member 15 is stationary.

[Second Embodiment]
Next, a second embodiment of the present invention will be described. In the present embodiment, two each of the first fixed electrode 17 and the second fixed electrode 18 in the electrostatic conversion device 1 in the first embodiment described above are provided for one wide portion 15b. It is a thing. Therefore, components equivalent to those in the first embodiment described above are denoted by the same names and reference numerals, and description thereof is omitted as appropriate.

<Configuration of electrostatic conversion device>
As shown in FIG. 5, the electrostatic conversion device 1 according to the present embodiment includes a semiconductor substrate 11 having an insulating film 12 formed on the upper surface, pillar members 13a and 13b, and beam members 14a and 14b in the Y direction. A plurality of first fixed electrodes 17a provided in pairs with respect to one wide portion 15b at a position spaced apart from the movable member 15 in the Y direction on the movable member 15 supported so as to be swingable. , 17b and second fixed electrodes 18a, 18b. The first fixed electrodes 17 a and 17 b and the second fixed electrodes 18 a and 18 b are connected to a pair of terminals 20 via a wiring 19.

  Here, the first fixed electrodes 17a and 17b are provided in line symmetry with respect to the movement trajectory of the movable member 15, in other words, in line symmetry with respect to a straight line along the Y direction passing through the substantially central portion of the wide portion 15b. It has been. Further, in a state where the movable member 15 is stationary, the first fixed electrodes 17a and 17b are spaced apart from the wide portion 15b by a predetermined distance in the X direction. The distance between the wide portion 15b and the first fixed electrodes 17a and 17b is set to a distance at which the first fixed electrodes 17a and 17b are affected by the electrostatic field of the insulating charging body 16 provided on the surface of the wide portion 15b. Has been.

  The second fixed electrodes 18a and 18b are provided in line symmetry with respect to the movement trajectory of the movable member 15, in other words, in line symmetry with respect to a straight line along the Y direction passing through the substantially central portion of the wide portion 15b. . The second fixed electrode 18a is disposed at a predetermined interval on the side away from the first fixed electrode 17a and the movable member 15 in the Y direction. Similarly, the second fixed electrode 18b is disposed at a predetermined interval on the side away from the first fixed electrode 17b and the movable member 15 in the Y direction.

  Here, a pair of first fixed electrodes 17a and 17b and a pair of second fixed electrodes 18a and 18b are arranged in association with each other in the wide portion 15b. The first fixed electrodes 17a and 17b and the second fixed electrodes 18a and 18b are arranged on the same straight line along the Y direction. As described above, in the state where the movable member 15 is stationary, the wide portion 15b faces the first fixed electrodes 17a and 17b in the X direction. From this state, when the movable member 15 moves in the Y direction toward the second fixed electrodes 18a and 18b, the wide portion 15b faces the second fixed electrodes 18a and 18b in the X direction. Become.

<Power generation operation of electrostatic conversion device>
Next, with reference to FIG. 6, the power generation operation by the electrostatic conversion device according to the present embodiment will be described.

  First, as shown in FIG. 6, when the movable electrode 15 is stationary, the first fixed electrodes 17a and 17b located near the wide portion 15b are insulated charging bodies provided on the surface of the wide portion 15b. Under the influence of the electrostatic field formed by 16, a positive charge corresponding to the negative charge of the insulating charged body 16 appears on the first fixed electrodes 17 a and 17 b by the principle of electrostatic induction.

  In this state, for example, when the electrostatic conversion device 1 is vibrated, the movable member 15 having a mass swings in the Y direction. When the movable member 15 moves in the positive direction in the Y direction, the wide portion 15b also moves in the positive direction in the Y direction and approaches the second fixed electrodes 18a and 18b. Then, since the second fixed electrodes 18a and 18b are closer to the insulating charging body 16 provided on the surface of the wide portion 15b than the first fixed electrodes 17a and 17b, they are more static than the first fixed electrodes 17a and 17b. In order to be more strongly affected by the electric field, a positive charge corresponding to the negative charge appears on the second fixed electrodes 18a and 18b by the principle of electrostatic induction. The positive charges are electrically connected to the first fixed electrode 17 in FIG. 6 because the first fixed electrodes 17a and 17b and the second fixed electrodes 18a and 18b are electrically connected via the external load 21. The positive charge that appears has moved.

  When the movable member 15 moves again in the negative direction in the Y direction from the state where the wide portion 15b is opposed to the second fixed electrodes 18a and 18b, the wide portion 15b is moved to the second fixed electrode as shown in FIG. It moves away from 18a, 18b and approaches the first fixed electrodes 17a, 17b. Then, since the first fixed electrodes 17a and 17b are more strongly affected by the insulating charged body 16 provided on the surface of the wide portion 15b than the second fixed electrodes 18a and 18b, positive charges are caused by electrostatic induction. Will appear. This positive charge has moved from the second fixed electrodes 18a and 18b.

  In this way, when the movable member 15 swings in the Y direction by vibrating the electrostatic conversion device 1, positive charges are alternately applied to the first fixed electrodes 17a and 17b and the second fixed electrodes 18a and 18b. As a result, a current flows through the external load 21.

  As described above, according to the present embodiment, as a result, the track of the insulating charging body 16 in which the first fixed electrodes 17a and 17b and the second fixed electrodes 18a and 18b are formed on the surface of the wide portion 15b. As a result, the insulating charged body 16 and the first fixed electrodes 17a and 17b and the second fixed electrodes 18a and 18b face each other in a plane perpendicular to the semiconductor substrate 11. Accordingly, the overlapping area between the insulating charged body 16 and the first fixed electrodes 17a and 17b and the second fixed electrodes 18a and 18b can be set without being restricted by the area of the semiconductor substrate 11, and the power generation efficiency can be set. Can be improved.

  In addition, according to the present embodiment, the electrostatic conversion can be performed on the two second side surfaces among the six surfaces forming the surface of the rectangular parallelepiped movable member 15. As a result, the output can be improved and the electrostatic conversion can be performed. Miniaturization of the apparatus can be realized. In the present embodiment, since the pair of first fixed electrodes 17a and 17b and the pair of second fixed electrodes 18a and 18b are provided for one wide portion 15b, the positive charge induced Since the amount increases, the output can be improved.

  In the present embodiment, as shown in FIG. 5, the case where four arm members 15a are provided on each of the second side surfaces of the movable member 15 has been described as an example, but the number of arm members 15a is limited to four. Needless to say, it can be set as appropriate. In this case, the numbers of the first fixed electrodes 17a and 17b and the second fixed electrodes 18a and 18b are also set according to the number of arm members 15a.

  Further, in the present embodiment, the case where the wide portion 15b is provided at a position facing the first fixed electrodes 17a and 17b in the X direction when the movable member 15 is stationary has been described as an example. The position to be provided is not limited to this, and can be set freely as appropriate. For example, the wide portion 15b is provided at a position facing the region between the first fixed electrodes 17a and 17b and the second fixed electrodes 18a and 18b in the X direction when the movable member 15 is stationary. May be.

[Third Embodiment]
Next, a third embodiment of the present invention will be described. In this embodiment, in the electrostatic conversion device 2 according to the second embodiment described above, a movable electrode is provided on the upper surface of the movable member 15, and a fixed electrode is further provided at a position facing the movable electrode 15. It is a thing. Therefore, components equivalent to those in the first and second embodiments described above are denoted by the same names and reference numerals, and description thereof is omitted as appropriate.

<Configuration of electrostatic conversion device>
As shown in FIGS. 7 and 8, the electrostatic conversion device 3 according to the present embodiment includes a semiconductor substrate (hereinafter referred to as “first semiconductor substrate”) 11 and an upper portion of the first semiconductor substrate 11. Are spaced apart from each other by a predetermined distance, and the spacer member 41 is disposed between the first semiconductor substrate 11 and the second semiconductor substrate 31 and keeps these distances at a predetermined distance. And. The spacer member 41 is made of metal and has a cylindrical shape having an opening that is substantially rectangular in plan view. In the opening, as shown in FIG. 8, column members 13a and 13b, beam members 14a and 14b, movable member 15, first fixed electrodes 17a and 17b, second fixed electrodes 18a and 18b, and A third fixed electrode 33 and a fourth fixed electrode 34 described later are accommodated. In addition, in FIG. 8, description is abbreviate | omitted except a cut surface.

  Here, on the first semiconductor substrate 11, column members 13 a and 13 b and a beam are formed on an insulating film (hereinafter referred to as “first insulating film”) 12 formed on the upper surface of the first semiconductor substrate 11. A pair of the movable member 15 supported by the members 14a and 14b so as to be swingable in the Y direction, and one wide portion 15b on the first insulating film 12 at a position spaced apart from the movable member 15 in the Y direction. A plurality of first fixed electrodes 17a and 17b and second fixed electrodes 18a and 18b are provided.

  Here, on the upper surface of the movable member 15, a plurality of plate-like projecting members 15 c that are suspended along the X direction are formed at predetermined intervals in the Y direction. As described above, since the movable member 15 is movable in the Y direction, as the movable member 15 moves, the protruding member 15c also moves in the Y direction. Further, an insulating charging body 16 charged with a negative charge is formed on the surface of the protruding member 15c.

  The second semiconductor substrate 31 is spaced apart from the second insulating film 32 formed on the surface of the second semiconductor substrate 31 facing the first semiconductor substrate 11 by a predetermined distance in the Y direction. A plurality of third fixed electrodes 33 and fourth fixed electrodes 34 provided alternately are provided. Here, the third fixed electrode 33 and the fourth fixed electrode 34 are connected to the pair of terminals 23 via the wiring 22 provided on the second semiconductor substrate 31 or the like. The plurality of third fixed electrodes 33 are electrically connected to one terminal 23 in common and the plurality of fourth fixed electrodes 34 are electrically connected to the other terminal 23 in common. . This terminal 23 is configured to be connectable to an external load 24.

  The second semiconductor substrate 31 is composed of a semiconductor substrate made of silicon or the like, and has an outer shape equivalent to that of the first semiconductor substrate 11. The second insulating film 32 is made of silicon oxide or the like and is formed on the lower surface of the second semiconductor substrate 31.

  The third fixed electrode 33 is composed of a metal plate-like member that protrudes downward from the second insulating film 32 and extends in the X direction. On the second insulating film 32, the upper surface of the movable member 15 and They are arranged at a predetermined interval. The third fixed electrode 33 is provided at a position facing the movable electrode 15c when the movable member 15 is stationary.

  The fourth fixed electrode 34 is composed of a metal plate-like member that protrudes downward from the second insulating film 32 and extends in the X direction. The third fixed electrode 34 is adjacent to the third insulating film 32 on the second insulating film 32. The electrodes 33 are arranged in parallel with each other and spaced apart at equal intervals. Note that the fourth fixed electrodes 34 positioned at both positive and negative ends in the Y direction are adjacent to the third fixed electrode 33 on only one of the positive side and the negative side in the Y direction.

<Power generation operation of electrostatic conversion device>
Next, the power generation operation of the electrostatic conversion device according to the present embodiment will be described with reference to FIGS. Note that the power generation operation using the first fixed electrodes 17a and 17b and the second fixed electrodes 18a and 18b is the same as that in the second embodiment described above, and thus the description thereof is omitted. Hereinafter, a power generation operation using the third fixed electrode 33 and the fourth fixed electrode 34 will be described.

  First, as shown in FIG. 9, the movable member 15 is opposed to the projecting member 15c in a state where the movable member 15 is stationary, and the third fixed electrode 33 is provided on the surface of the projecting member 15c. The positive charge corresponding to the negative charge of the insulating charged body 16 appears on the third fixed electrode 33 due to the electrostatic induction principle.

  In this state, for example, when the electrostatic conversion device 1 is vibrated, the movable member 15 having a mass swings in the Y direction. When the movable member 15 moves in the positive direction in the Y direction, as shown in FIG. 10, the protruding member 15 c also moves in the positive direction in the Y direction and approaches the fourth fixed electrode 34. Then, the fourth fixed electrode 34 is closer to the insulating charging body 16 provided on the surface of the projecting member 15 c than the third fixed electrode 33, and thus the influence of the electrostatic field is stronger than the third fixed electrode 33. Therefore, a positive charge corresponding to the negative charge appears on the fourth fixed electrode 34 due to the principle of electrostatic induction. This positive charge is the positive charge that appears on the third fixed electrode 33 in FIG. 9 because the third fixed electrode 33 and the fourth fixed electrode 34 are electrically connected via the external load 24. Has been moved.

  When the movable member 15 moves again in the negative direction of the Y direction from the state shown in FIG. 10, the protruding portion 15 c moves away from the fourth fixed electrode 34 and moves to the third fixed electrode 33 as shown in FIG. 9. Get closer. Then, since the third fixed electrode 33 is more strongly affected by the insulating charged body 16 provided on the surface of the protruding member 15c than the fourth fixed electrode 34, a positive charge appears due to electrostatic induction. . This positive charge has moved from the fourth fixed electrode 34.

  In this manner, when the movable member 15 swings in the Y direction by vibrating the electrostatic conversion device 1, positive charges are alternately induced in the third fixed electrode 33 and the fourth fixed electrode 34, A current flows through the external load 24. At this time, as described in the second embodiment, positive charges are alternately induced in the first fixed electrode 17 and the second fixed electrode 18, and a current also flows in the external load 24. Thereby, according to this Embodiment, among the six surfaces forming the surface of the movable member 15 having a rectangular parallelepiped shape, electrostatic conversion can be performed on a total of three surfaces, that is, the two second side surfaces and the upper surface. As a result, it is possible to improve the output and reduce the size of the electrostatic conversion device.

[Fourth Embodiment]
Next, a fourth embodiment of the present invention will be described. In the present embodiment, components equivalent to those in the first to third implementations described above are denoted by the same names and reference numerals, and description thereof will be omitted as appropriate.

<Configuration of electrostatic conversion device>
As shown in FIGS. 11 to 14, the electrostatic conversion device 4 according to the present embodiment includes a first semiconductor substrate 11 and a first semiconductor substrate 11 disposed above the first semiconductor substrate 11 at a predetermined distance. And a spacer member 41 disposed between the first semiconductor substrate 11 and the second semiconductor substrate 31 and maintaining these distances at a predetermined distance. In FIG. 13, the description other than the cut surface is omitted.

<< Configuration of First Semiconductor Substrate >>
The first semiconductor substrate 11 has a substantially lattice-like movable member 50 in plan view supported on the first insulating film 12 by a column member 13a, 13b and a beam member 14a, 14b so as to be swingable in the Y direction. A plurality of fifth fixed electrodes 61 and sixth fixed electrodes 62 are provided around the movable member 50. Here, the fifth fixed electrode 61 and the sixth fixed electrode 62 are electrically connected via the external load 24 by the wiring 22 provided on the first semiconductor substrate 11 or the like. Here, the movable member 50, the fifth fixed electrode 61, and the sixth fixed electrode 62 are insulated and separated from each other on the first semiconductor substrate 11. In the present embodiment, a plurality of the fifth fixed electrodes 61 and the sixth fixed electrodes 62 are provided along the X direction, and are connected to the pair of terminals 20 via the wiring 19. The plurality of fifth fixed electrodes 61 are electrically connected in common to one terminal 20, and the plurality of sixth fixed electrodes 62 are electrically connected in common to the other terminal 20. This terminal 20 is configured to be connectable to an external load 21.

  The movable member 50 is composed of a base 51 made of a rectangular parallelepiped columnar member extending along the X direction and a columnar member extending along the Y direction, and one end of each side surface of the base 51 along the X direction. The plurality of first members 52 connected to each other at a predetermined interval in the X direction and a pair of columnar members extending along the X direction, and the other end of the first member 52 is connected. The second member 53 includes a plurality of third members 54 that are formed of columnar members extending along the X direction, are provided on top of the first member 52, and are spaced apart from each other by a predetermined distance in the Y direction. ing. Each of the first member 52, the second member 53, and the third member 54 is disposed symmetrically with respect to the extending direction of the first member 52. Such a movable member 50 is made of metal. In addition, an insulating charging body 16 is formed on the surface of the movable member 50 together with the column members 13a and 13b and the beam members 14a and 14b. The insulated charging body 16 functions as an electret in which at least a wide portion 52a and a third member 54 described later are charged with electrons in advance. Furthermore, the movable member 50 is connected to the ground by a wiring (not shown).

  Here, the other end of the beam members 14a and 14b facing each other is connected to two side surfaces of the base 51 facing the column members 13a and 13b. Thereby, the movable member 50 is suspended above the first semiconductor substrate 11 by the beam members 14a and 14b. At this time, since the beam members 14a and 14b have flexibility in the Y direction, the movable member 50 is in a state where it can swing in the Y direction and in a state where it can reciprocate on both positive and negative sides in the Y direction. Therefore, when the electrostatic conversion device 4 itself vibrates, the movable member 50 swings in the Y direction.

  Also, a substantially rectangular wide portion 52a in plan view having a large length in the X direction is provided at a substantially central portion in the Y direction of the first member 52. In the present embodiment, four third members 54 are provided. These are disposed at positions above the first member 52 at a predetermined distance from the wide portion 52a on both the positive and negative sides in the Y direction so as to sandwich the wide portion 52a.

  The fifth fixed electrode 61 is composed of a metal rod-like member protruding upward from the insulating film 12. In the state where the movable member 50 is stationary, such a fifth fixed electrode 61 is arranged between the wide portions 52a adjacent to the wide portions 52a adjacent to each other in the X direction at equal intervals from the wide portions 52a. They are spaced apart. In addition, about the wide part 52a located in the both ends in the X direction among the wide parts 52a, the 5th fixed electrode 61 is provided also in the side which is not adjacent to the wide part 52a. In this case, the distance between the fifth fixed electrode 61 and the wide portion 52a is provided at the same interval as that provided between the wide portion 52a. Here, the distance between the wide portion 52a and the fifth fixed electrode 61 is set to a distance at which the fifth fixed electrode 61 is affected by the electrostatic field of the insulating charging body 16 provided on the surface of the wide portion 52a. Yes.

  The sixth fixed electrode 62 is composed of a metal rod-like member protruding upward from the insulating film 12. The sixth fixed electrode 62 is arranged at a predetermined distance from the fifth fixed electrode 61 on both the positive and negative sides in the Y direction. The sixth fixed electrode 62 is connected to the ground by a wiring (not shown).

<< Configuration of Second Semiconductor Substrate >>
On the second semiconductor substrate 31, a plurality of seventh fixed electrodes 71 provided on the second insulating film 32 formed on the lower surface of the second semiconductor substrate 31 with a predetermined spacing in the Y direction. And an eighth fixed electrode 72. Here, the seventh fixed electrode 71 and the eighth fixed electrode 72 are connected to the pair of terminals 23 via the wiring 22 provided on the second semiconductor substrate 31 or the like. The plurality of seventh fixed electrodes 71 are electrically connected to one terminal 23 in common and the plurality of eighth fixed electrodes 72 are electrically connected to the other terminal 23 in common. . This terminal 23 is configured to be connectable to an external load 24.

  The seventh fixed electrode 71 is composed of a metal plate-like member that protrudes downward from the second insulating film 32 and extends in the X direction. On the second insulating film 32, the upper surface of the movable member 50 and They are arranged at a predetermined interval. The seventh fixed electrode 71 is provided at a position facing the third member 54 when the movable member 50 is stationary.

  The eighth fixed electrode 72 is composed of a metal plate-like member that protrudes downward from the second insulating film 32 and extends in the X direction, and is adjacent to the seventh fixed electrode on the second insulating film 32. The electrodes 71 are arranged in parallel to each other and spaced apart at equal intervals. Note that the eighth fixed electrodes 72 located at both positive and negative ends in the Y direction are adjacent to the seventh fixed electrode 71 on only one of the positive side and the negative side in the Y direction.

  The spacer member 41 is made of metal and has a cylindrical shape having an opening that is substantially rectangular in a plan view. In the opening, as shown in FIGS. 11 and 12, pillar members 13a and 13b, beam members 14a and 14b, movable member 50, fifth fixed electrode 61, sixth fixed electrode 62, and seventh member The fixed electrode 71 and the eighth fixed electrode 72 are accommodated. Such a spacer member 41 is connected to the ground by a wiring (not shown).

<Power generation operation of electrostatic conversion device>
Next, with reference to FIGS. 11-14, the electric power generation operation | movement by the electrostatic transducer which concerns on this Embodiment is demonstrated.

  First, the power generation operation using the fifth fixed electrode 61 and the sixth fixed electrode 62 will be described.

  First, the fifth fixed electrode 61 positioned near the wide portion 52b in a state where the movable member 50 is stationary is affected by the electrostatic field formed by the insulating charged body 16 provided on the surface of the wide portion 52b. In response to this, a positive charge corresponding to the negative charge of the insulating charged body 16 appears on the fifth fixed electrode 61 by the principle of electrostatic induction.

  In such a state, for example, when the electrostatic conversion device 4 is vibrated, the movable member 50 is in one of positive and negative directions in the Y direction (in the following, a case where the movable member 50 moves in the positive direction will be described as an example). , The wide portion 52b also moves to the positive side in the Y direction and approaches the sixth fixed electrode 62 located on the positive side in the Y direction with respect to the fifth fixed electrode. Then, since the sixth fixed electrode 62 is closer to the insulating charging body 16 provided on the surface of the wider portion 52 b than the fifth fixed electrode 61, the insulating charging body 16 is formed more than the fifth fixed electrode 61. In order to receive the influence of the electrostatic field more strongly, a positive charge corresponding to the negative charge appears on the sixth fixed electrode 62 by the principle of electrostatic induction. This positive charge is that the fifth fixed electrode 61 and the sixth fixed electrode 62 are electrically connected via the external load 21, so that the positive charge appearing on the fifth fixed electrode 61 moves. It is a thing.

  From this state, when the movable member 50 moves again in the negative direction in the Y direction, the wide portion 52 b moves away from the sixth fixed electrode 62 and approaches the fifth fixed electrode 61. Then, since the fifth fixed electrode is more strongly affected by the electrostatic field formed by the insulating charging body 16 than the sixth fixed electrode 62, a positive charge appears due to electrostatic induction. This positive charge has moved from the sixth fixed electrode 62 located on the positive side in the Y direction.

  When the movable member 50 further moves to the negative side in the Y direction, the wide portion 52 b moves away from the fifth fixed electrode 61 and approaches the sixth fixed electrode 62. Then, since the sixth fixed electrode 62 is more strongly affected by the electrostatic field formed by the insulating charged body 16 than the fifth fixed electrode 61, a positive charge appears due to electrostatic induction. This positive charge has moved from the fifth fixed electrode 61.

  From this state, when the movable member 50 moves again to the positive side in the Y direction, the wide portion 52 b moves away from the sixth fixed electrode 62 and approaches the fifth fixed electrode 61. Then, since the fifth fixed electrode is more strongly affected by the electrostatic field formed by the insulating charging body 16 than the sixth fixed electrode 62, a positive charge appears due to electrostatic induction. This positive charge has moved from the sixth fixed electrode 62 located on the negative side in the Y direction.

  As described above, when the movable member 50 is swung in the Y direction by vibrating the electrostatic conversion device 4, positive charges are alternately induced in the fifth fixed electrode 61 and the two sixth fixed electrodes 62. As a result, a current flows through the external load 24.

  According to the present embodiment, the fifth fixed electrode 61 and the sixth fixed electrode 62 are juxtaposed on the track of the insulating charging body 16 formed on the surface of the wide portion 52b, whereby the first semiconductor substrate 11 is provided. Insulating charging body 16, fifth fixed electrode 61, and sixth fixed electrode 62 face each other in a plane perpendicular to. Therefore, it is possible to set the overlapping area between the insulating charged body 16, the fifth fixed electrode 61, and the sixth fixed electrode 62 without being restricted by the area of the first semiconductor substrate 11, thereby improving the power generation efficiency. Can be made.

  In addition, according to the present embodiment, by providing the sixth fixed electrode 62 on both sides of the fifth fixed electrode 61, the movable member 50 generates power even if it moves to either the positive or negative side in the Y direction. Can do.

  Next, the power generation operation using the seventh fixed electrode 71 and the eighth fixed electrode 72 will be described.

  This case is equivalent to the power generation operation using the third fixed electrode 33 and the fourth fixed electrode 34 in the third embodiment. That is, the seventh fixed electrode 71 corresponds to the third fixed electrode 33, the eighth fixed electrode 72 corresponds to the fourth fixed electrode 34, and the third member 54 corresponds to the protruding member 15c. Therefore, when the movable member 50 moves to both the positive and negative sides in the Y direction due to the vibration of the electrostatic conversion device 4, the positive electrode is positively connected between the seventh fixed electrode 71 and the eighth fixed electrode 72 via the external load 24. As the charge moves, a current flows through the external load 24 as a result.

  Thereby, according to this Embodiment, since electrostatic conversion can be performed in many surfaces of the movable member 50, as a result, the improvement of output and size reduction of an electrostatic conversion apparatus are realizable.

<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. 15A to 15Q.

  First, for example, a first semiconductor substrate 11 made of silicon having an insulating film 12 made of silicon oxide formed on the upper surface is prepared. The first semiconductor substrate 11 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 insulating film 12.

  A first seed layer 101 is formed on the insulating film 12 on the first semiconductor substrate 11 as shown in FIG. 15A. The first seed layer 101 can be formed, for example, by depositing titanium on the insulating film 12 by sputtering or vapor deposition, and then depositing gold thereon. 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, for example, by plating, and then the resist pattern is removed, so that the first seed layer 101 is formed as shown in FIG. 15B. 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. 15C, the first metal pattern 102 is formed on the insulating film 12. The state is separated from each other. Thereby, the lower part of the column members 13a and 13b, the lower part of the fifth fixed electrode 61, the lower part of the sixth fixed electrode 62, and a part of the spacer member 41 are formed.

  For example, the first seed layer is removed by wet etching the gold on the first seed layer 101 with an aqua regia etchant composed of nitric acid and hydrochloric acid, and then exposing the first seed layer exposed by this wet etching. Titanium in the lower layer of the layer 101 can be wet-etched 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 insulating film 12 as shown in FIG. 15D. At this time, the upper surface of the first metal pattern 102 is exposed to the surface of the first sacrificial layer 103. For example, the first sacrificial layer 103 is formed by coating a photosensitive organic resin made of PBO (polybenzoxazole) on the insulating film 12 to form a coating film, and patterning the coating film by a known lithography technique. Can be formed. 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. 15E, 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. Thereby, the upper part of the column members 13a and 13b, the beam members 14a and 14b, a part of the movable member 50 (the lower part of the base 51, the first member 52 and the second member 53), and the upper part of the fifth fixed electrode 61 The upper part of the sixth fixed electrode 62 and a part of the spacer member 41 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. 15G. 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. 15H, 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. 15I, 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, a part of the movable member 50 (the upper part of the base 51, the first member 52, and the second member 42) and a part of the spacer member 41 are formed.

  After selectively removing the third seed layer 107 by etching, a third sacrificial layer 109 is formed on the second sacrificial layer 106 as shown in FIG. 15J. At this time, the upper surface of the third metal pattern 108 is exposed to the surface of the third sacrificial layer 109. The step of forming the third sacrificial layer 109 can be performed by a method equivalent to the step of forming the first sacrificial layer 103 and the second sacrificial layer 106 described above.

  After the third sacrificial layer 109 is formed, as shown in FIG. 15K, the fourth seed layer 110 is formed on the third sacrificial layer 109 by a method similar to the method of forming the first seed layer 101 and the like. Then, a fourth metal pattern 111 is formed on the fourth seed layer 110 by a method equivalent to the method of forming the first metal pattern 102 and the like. Here, when the third metal pattern 108 is formed, the resist pattern serving as a mask may have a thickness of about 20 μm and a plating thickness of about 10 μm.

  After the fourth metal pattern 111 is formed, as shown in FIG. 15L, the fourth seed layer is masked by using the fourth metal pattern 111 as a mask by a method equivalent to the method in which the first seed layer 101 and the like are removed by etching. 110 is removed. As a result, the fourth metal pattern 111 is separated on the third sacrificial layer 109. Thereby, a part of the movable member 50 (third member 54) and a part of the spacer member 41 are formed.

  After selectively removing the fourth seed layer 111 by etching, the first sacrificial layer 103, the second sacrificial layer 106, and the third sacrificial layer 109 are removed as shown in FIG. 15M. As a result, a space is formed below the second seed layer 104 constituting a part of the movable member 50. The removal of the first sacrificial layer 103, the second sacrificial layer 106, and the third sacrificial layer 109 is performed by, for example, using an ozone asher device to convert ozone into the first sacrificial layer 103, the second sacrificial layer 106, and the third sacrificial layer 103. This can be done by acting on the sacrificial layer 109.

  After removing the first sacrificial layer 103, the second sacrificial layer 106, and the third sacrificial layer 109, as shown in FIG. 15N, the first seed layer 101, the first metal pattern 102, the second seed Of the layer 104, the second metal pattern 105, the third seed layer 107, and the third metal pattern 108, the surface of the members constituting the column members 13a and 13b, the beam members 14a and 14b, and the movable member 50 is repellent. The insulating film 112 is formed by electrodeposition using an electrodeposition material that exhibits aqueous, insulating, and charging properties. The insulating film 112 constitutes the above-described insulating charged body 16. A specific example of the manufacturing process of the insulating film 112 will be described below.

  For example, an electrodeposition solution (for example, INSULEED3020X manufactured by Nippon Paint Co., Ltd.) in which sulfonium cations are dispersed is adjusted to 30 ° C., and the first semiconductor substrate 11 that has undergone the above-described steps is contained in this electrodeposition solution. The counter electrode made of platinum is immersed. In this state, a negative voltage is applied to the members constituting the column members 13a and 13b, the beam members 14a and 14b, and the movable member 50, and a positive voltage is applied to the counter electrode. That is, the members constituting the column members 13a and 13b, the beam members 14a and 14b, and the movable member 50 are set as the negative electrode, the counter electrode is set as the positive electrode and immersed in the electrodeposition liquid, and the voltage is applied using a constant voltage source. Cation electrodeposition is carried out by applying. By this electrodeposition, the insulating film forming material dispersed in the electrodeposition liquid is deposited on the surfaces of the members constituting the column members 13a and 13b, the beam members 14a and 14b and the movable member 50 to which a negative voltage is applied. Thus, the insulating film 112 is formed. The material dispersed in the electrodeposition liquid does not adhere to the surface of the insulating film 12 to which no negative voltage is applied or other members, and the column members 13a and 13b and beam members 14a and 14b to which a negative voltage is applied. In addition, the insulating film 112 can be selectively formed only on the members constituting the movable member 50.

  After the insulating film 112 is formed, the first semiconductor substrate 11 is washed with water, dried, and then subjected to heat treatment at 190 ° C. for 25 minutes in a nitrogen atmosphere, whereby the insulating film 112 is thermally cured. To do.

  After the insulating film 112 is thermally cured, the first semiconductor substrate 11 is charged by, for example, a known method such as an electron beam method, a liquid contact method, or a corona discharge method. For example, when corona discharge is used, the lower surface of the first semiconductor substrate 11 and the column members 13a and 13b, the beam members 14a and 14b, and the movable member 50 are grounded, and DC discharge is performed. The conditions for the corona discharge may be that the applied voltage is -1000 V and the application time is 60 minutes. By such charging treatment, the surface of the insulating film 112 is in a state where negative charges are charged.

  Next, for example, a second semiconductor substrate 31 made of silicon in which a second insulating film 32 made of silicon oxide is formed on one surface is prepared. Here, the second semiconductor substrate 31 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 second insulating film 32.

  With respect to such a second semiconductor substrate 31, as shown in FIG. 15O, the fifth seed is formed on the second insulating film 32 by a method similar to the method of forming the first seed layer 101 and the like described above. A layer 301 is formed, and a fifth metal pattern 302 is formed on the fifth seed layer 301 by a method similar to the method of forming the first metal pattern 102 and the like. Here, when the fifth metal pattern 302 is formed, for example, the resist pattern serving as a mask may have a thickness of about 40 μm and a thickness of about 25 μm for plating. Thereby, a part of each of the seventh fixed electrode 71, the eighth fixed electrode 72, and the spacer member 41 is formed.

  After forming the fifth metal pattern 302, as shown in FIG. 15P, the sixth metal pattern 303 is formed on the fifth metal pattern 302 by the same method as the method of forming the first metal pattern 102 described above. Form. Here, when the sixth metal pattern 303 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 the spacer member 41 is formed.

  After the sixth metal pattern 303 is formed, the fifth seed layer is masked by using the fifth metal pattern 302 and the sixth 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. As shown in FIG. 15Q, the fifth metal pattern 302 and the sixth metal pattern 303 are separated from each other on the fifth seed layer sacrificial layer 301 as shown in FIG. 15Q. Thereby, the seventh fixed electrode 71, the eighth fixed electrode 72, and a part of the spacer member 41 are formed.

  Next, as shown in FIG. 15R, the surface of the first semiconductor substrate 11 on which the first insulating film 12 is formed and the side of the second semiconductor substrate 31 on which the second insulating film 32 is formed. The upper surface of the fourth metal pattern 111 formed on the first semiconductor substrate 11 and the upper surface of the sixth metal pattern 303 formed on the second semiconductor substrate 31 are bonded together. 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. Thereby, the electrostatic conversion apparatus 4 is completed.

  In addition, it can manufacture by the method equivalent to the manufacturing method of the electrostatic transducer 4 mentioned above also about the electrostatic transducers 1-3 in the 1st-3rd embodiment mentioned above.

  For example, in the case of the electrostatic conversion device 1, the first seed layer 101 and the first metal pattern 102 allow the lower portions of the column members 13 a and 13 b, the first fixed electrode 17, and the second fixed electrode 18, respectively. Form. Further, the second seed layer 104 and the second metal pattern 105 allow the upper portions of the column members 13a and 13b, the first fixed electrode 17 and the second fixed electrode 18, and the beam members 14a and 14b and the movable member. 15 is formed. Then, an insulating film serving as the insulating charging body 16 may be formed on the surfaces of the members constituting the column members 13a and 13b, the beam members 14a and 14b, and the movable member 15.

  In the case of the electrostatic conversion device 2, the first seed layer 101 and the first metal pattern 102 are used to form the pillar members 13a and 13b, the first fixed electrodes 17a and 17b, and the second fixed electrodes 18a and 18b. Each lower part is formed. Further, by the second seed layer 104 and the second metal pattern 105, the column members 13a and 13b, the upper portions of the first fixed electrodes 17a and 17b and the second fixed electrodes 18a and 18b, and the beam members 14a, 14b and the movable member 15 are formed. Then, an insulating film serving as the insulating charging body 16 may be formed on the surfaces of the members constituting the column members 13a and 13b, the beam members 14a and 14b, and the movable member 15.

  Further, in the case of the electrostatic conversion device 3, the first seed layer 101 and the first metal pattern 102 are used to form the pillar members 13a and 13b, the first fixed electrodes 17a and 17b, and the second fixed electrodes 18a and 18b. Each lower part and a part of spacer member 41 are formed. Further, by the second seed layer 104 and the second metal pattern 105, the column members 13a and 13b, the upper portions of the first fixed electrodes 17a and 17b and the second fixed electrodes 18a and 18b, and the beam members 14a, 14b, a part of the movable member 15 (a part excluding the protruding member 15c) and a part of the spacer member 41 are formed. The third seed layer 107 and the third metal pattern 108 form part of the movable member 15 (projecting member 15c) and part of the spacer member 41. In addition, the third fixed electrode 33, the fourth fixed electrode 34, and a part of the spacer member 41 are formed by the fifth seed layer 301 and the fifth metal pattern 302. Further, a part of the spacer member 41 is formed by the sixth metal pattern 303. Then, an insulating film serving as the insulating charging body 16 may be formed on the surfaces of the members constituting the column members 13a and 13b, the beam members 14a and 14b, and the movable member 15.

  In the first to fourth embodiments, a fixed electrode may be provided below the wide portion 15b or the wide portion 52a. This makes it possible to further increase the amount of power generation. In this case, at least one metal pattern is further formed between the first metal pattern 102 and the second metal pattern 105, and the fixed electrode is formed by the first metal pattern 102. The fixed electrode may be separated from the wide portion 15b or 52a by the formed metal pattern.

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

  DESCRIPTION OF SYMBOLS 1-4 ... Electrostatic conversion apparatus, 11 ... (1st) semiconductor substrate, 12 ... (1st) insulating film, 13a, 13b ... Column member, 14a, 14b ... Beam member, 15 ... Movable member, 15a ... Arm member, 15b ... Wide portion, 15c ... Projecting member, 16 ... Insulated charged body, 17, 17a, 17b ... First fixed electrode, 18, 18a, 18b ... Second fixed electrode, 19, 22 ... Wiring, 20 , 23 ... terminals, 21, 24 ... external load, 31 ... second semiconductor substrate, 32 ... second insulating film, 33 ... third fixed electrode, 34 ... fourth fixed electrode, 41 ... spacer member, 50 ... movable member, 51 ... base, 52 ... first member, 52a ... wide part, 53 ... second member, 54 ... third member, 61 ... fifth fixed electrode, 62 ... sixth fixed electrode, 71 ... seventh fixed electrode, 72 ... eighth fixed electrode, 101 ... first seed layer, 102 ... 1 metal pattern, 103 ... first sacrificial layer, 104 ... second seed layer, 105 ... second metal pattern, 106 ... second sacrificial layer, 107 ... third seed layer, 108 ... third Metal pattern 109 ... third sacrificial layer 110 ... fourth seed layer 111 ... fourth metal pattern 112 ... insulating film 301 ... fifth seed layer 302 ... fifth metal pattern 303 ... 6th metal pattern.

Claims (9)

A substrate,
A movable member provided above the substrate and supported so as to be movable in a first direction parallel to the plane of the substrate;
An arm member having one end connected to the movable member and extending in the first direction;
A first charged body provided at the other end of the arm member;
First provided on the substrate and spaced apart from the movement locus of the first charging body by a predetermined distance in a second direction parallel to the plane and perpendicular to the first direction. A fixed electrode;
An electrostatic conversion device comprising: a second fixed electrode that is provided vertically on the substrate and is provided in parallel with the first fixed electrode along the first direction. A first terminal connected to an external load and a second terminal;
The first terminal is connected to the first fixed electrode;
The electrostatic conversion device according to claim 1, wherein the second terminal is connected to the second fixed electrode. The electrostatic conversion device according to claim 1, wherein the arm member is provided on both sides of the movable member. 4. The electrostatic according to claim 1, wherein the first fixed electrode and the second fixed electrode are provided at positions that are line-symmetric with respect to the movement locus. 5. Conversion device. 5. The electrostatic conversion device according to claim 1, wherein the second fixed electrode is provided on both sides of the first fixed electrode in the first direction. 6. A pair of columnar pillar members vertically spaced apart from each other in the second direction on the substrate;
One end is supported by the upper end of one of the pillar members, and further includes a pair of beam members extending in the plane direction of the substrate toward the other pillar member,
The movable member has a rectangular parallelepiped shape, and is disposed above the substrate by connecting the other end of the beam member to a pair of first side surfaces facing the column member,
The electrostatic conversion device according to any one of claims 1 to 5, wherein the arm member is provided on a second side surface orthogonal to the first side surface of the movable member. A second charged body suspended from the upper surface of the movable member;
A third fixed electrode disposed opposite to the second charged body above the movable member;
The fourth fixed electrode further comprising a fourth fixed electrode disposed above the movable member and spaced from the third fixed electrode in the first direction. The electrostatic conversion device according to any one of claims. A plurality of the second charged bodies are provided at a predetermined interval in the first direction,
The electrostatic conversion device according to claim 7, wherein a plurality of the third fixed electrodes and the fourth fixed electrodes are alternately provided in the second direction. A substrate, a movable member provided above the substrate and supported so as to be movable in a first direction parallel to the plane of the substrate, and one end connected to the movable member, in the first direction An extending arm member, a first charged body provided at the other end of the arm member, and a suspension suspended from the substrate, parallel to the plane and moving from the movement locus of the first charged body A first fixed electrode provided at a predetermined distance in a second direction perpendicular to the first direction, and the first fixed electrode suspended from the substrate and extending along the first direction. And a second fixed electrode arranged side by side, and a manufacturing method of an electrostatic conversion device comprising:
A first step of preparing, as the substrate, a silicon substrate having an insulating film formed on the upper surface;
A photoresist is applied on the insulating film, and the photoresist is exposed using a mask pattern having a predetermined shape, thereby forming a first resist pattern in which a first opening is formed at a predetermined location. A second step of:
After a metal is deposited in the first opening by plating to form a first metal pattern, the first resist pattern is removed to remove the lower portion of the first fixed electrode and the second fixed A third step of forming a lower portion of the electrode;
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;
After depositing a metal in the second opening by plating and forming a second metal pattern, the second resist pattern is removed, whereby the upper portion of the first fixed electrode, the second A sixth step of forming an upper part of the fixed electrode, the movable member and the arm member;
A seventh step of removing the first sacrificial layer;
And an eighth step of forming the first charged body by electrodeposition on the arm member.

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