WO2009113344A1

WO2009113344A1 - Variable capacitance element

Info

Publication number: WO2009113344A1
Application number: PCT/JP2009/051972
Authority: WO
Inventors: 義宏小中; 光治竹村; 悌二山本; 順一吉田
Original assignee: 株式会社村田製作所
Priority date: 2008-03-11
Filing date: 2009-02-05
Publication date: 2009-09-17

Abstract

Insulating first and second substrates (1, 2) having through-holes (3, 4) in which copper (13, 14) is filled are disposed so that the respective substrate surfaces face each other with a space in-between. A fixed electrode (5) conducted to the copper (13) is formed on the facing substrate surface (11) of the first substrate (1). An insulating stopper (10) is provided on the surface of the fixed electrode (5). A movable electrode (7) conducted through a beam portion (6) to the copper (14) is formed on the facing substrate surface (12) of the second substrate (2). The movable electrode (7) is spring-biased by the beam portion (6) toward the fixed electrode (5) and is floated from the second substrate (2). When a voltage is not applied to a driving electrode (9), the distance between the fixed electrode (5) and the movable electrode (7) narrows. When the voltage is applied, the movable electrode (7) moves toward the second substrate (2), widening the distance between the fixed electrode (5) and the movable electrode (7). This distance change causes the change of capacitance. A signal conduction path passing through this capacitance portion is formed by the path passing the copper (13, 14).

Description

Variable capacitance element

The present invention relates to a variable capacitance element that can be varied in capacitance, for example, applied to various electric circuits.

FIG. 9a and FIG. 9b are cross-sectional views showing a proposed example of a micro electromechanical switch as a variable capacitance element (see, for example, Patent Document 1). As shown in FIG. 9 a, a signal line (wiring) 48 and a bottom electrode 44 are provided on the substrate 42. Further, a movable electrode portion 47 is provided on the substrate 42 via an anchor structure portion 49. The movable electrode portion 47 has spring-like portions on both ends, and is disposed with a distance from the substrate 42. The movable electrode portion 47, the bottom electrode 44, the signal line 48, and the like are manufactured on the substrate 42 by using a thin film forming technique.

In the state shown in FIG. 9 a, the central portion of the movable electrode portion 47 is separated from the signal line 48. In this state, the capacitance between the movable electrode portion 47 and the signal line 48 is small, and the switch is turned off. On the other hand, when a voltage is applied to the movable electrode portion 47, the movable electrode portion 47 is attracted toward the bottom electrode 44 by electrostatic force as shown in FIG. 9b. And the center part of the movable electrode part 47 approaches the signal line 48, the capacity | capacitance between the movable electrode part 47 and the wiring line 48 becomes large, and it will be in a switch-on state.

JP 2001-143595 A

However, since the variable capacitance element shown in FIGS. 9a and 9b forms the wiring by using the thin film formation technique as described above, the loss in the wiring becomes large, and it is difficult to achieve high Q. There's a problem.

Also, the variable capacitance element as shown in FIGS. 9a and 9b has a problem that self-actuation occurs when a high-power signal is input to the signal line 48. FIG. The reason is that the direction in which the movable electrode portion 47 is displaced when a voltage is applied to the movable electrode portion 47 is a direction approaching the signal line 48, and when a signal is input to the signal line 48, this signal This is because the direction in which the movable electrode portion 47 is displaced by the generated electrostatic force is also a direction approaching the signal line 48. That is, when a high-power signal is input to the signal line 48, the variable capacitance element is drawn to the signal line 48 side by the electrostatic force without applying a voltage to the movable electrode portion 47, It will be displaced.

Furthermore, the variable capacitance element needs to have the configuration shown in FIGS. 9a and 9b in the package. Therefore, there is a problem that a loss occurs in the sealing portion between this package and the configuration shown in FIGS. 9a and 9b, and the cost is increased because the package forming process is complicated.

In order to solve the problems as described above, the present invention has the following configuration. That is, according to the present invention, the insulating first substrate and the insulating second substrate are arranged with the substrate surfaces facing each other with a space therebetween, and the first substrate is arranged in the thickness direction of the substrate. A first through hole penetrating through the second substrate and a second through hole penetrating in the thickness direction of the substrate are formed in the second substrate, and the first and second through holes are filled with a conductor, respectively. A fixed electrode is formed on the surface of the counter substrate of the first substrate and is electrically connected to the conductor filled in the first through hole; and on the surface of the counter substrate of the second substrate, A movable electrode is formed in the conductor filled in the second through-hole through the beam portion, and the movable substrate is urged toward the fixed electrode by the beam portion. The movable electrode and the second substrate are arranged with a space therebetween in a state of floating from the second substrate. At least one of the fixed electrodes is provided with an insulator on the surface facing the counterpart electrode, and the second substrate is provided with a drive electrode that draws and moves the movable electrode toward the second substrate. When the voltage is not applied to the drive electrode, the movable electrode is pressed against the fixed electrode through the insulator, and when the voltage is applied to the drive electrode, the movable electrode moves to the second substrate side. The capacitance between the fixed electrode and the movable electrode is changed by moving in a direction away from the fixed electrode, and the conductor filled in the second through hole, the beam portion, Means for solving the problem is configured such that a signal conduction path through the capacitor portion between the movable electrode and the fixed electrode is formed by a path passing through the conductor filled in the first through hole.

Further, according to the present invention, the insulating first substrate and the insulating second substrate are arranged with the substrate surfaces facing each other with a space therebetween, and the first substrate is arranged in the thickness direction of the substrate. A first through-hole and a second through-hole penetrating are formed, and the first and second through-holes are filled with a conductor, respectively, on the surface of the counter substrate of the first substrate. Is formed with a first fixed electrode conducting to the conductor filled in the first through hole and a second fixed electrode conducting to the conductor filled in the second through hole. A movable electrode is formed on the opposite substrate surface of the substrate through a beam portion, and the movable electrode is urged toward the fixed electrode side by the beam portion and floats from the second substrate. The second substrate is disposed at an interval, and at least one of the movable electrode and the fixed electrode An insulator is provided on the surface facing the counterpart electrode, and a driving electrode is formed on the second substrate to move the movable electrode toward the second substrate, and a voltage is applied to the driving electrode. When no voltage is applied, the movable electrode is pressed against the first and second fixed electrodes through the insulator, and when a voltage is applied to the drive electrode, the movable electrode moves to the second substrate side. Thus, the capacitance between the fixed electrode and the movable electrode is changed by moving in a direction away from the first and second fixed electrodes, and the conductor filled in the first through hole A capacitor portion between the movable electrode and the first fixed electrode, a capacitor portion between the movable electrode and the second fixed electrode, and a conductor filled in the second through hole. The signal conduction path is formed by the path It is characterized.

In the variable capacitance element of the present invention, the insulating first substrate and the insulating second substrate are disposed with their substrate surfaces facing each other with a gap therebetween. The movable electrode is formed on the counter substrate surface of the second substrate via a beam portion. The movable electrode is pressed against the fixed electrode formed on the counter substrate surface of the first substrate when no voltage is applied to the drive electrode. The movable electrode moves toward the second substrate and moves away from the fixed electrode when a voltage is applied to the drive electrode.

In the present invention, when a voltage is applied to the signal conduction path, an electrostatic force is generated in a direction attracting each other between the fixed electrode and the movable electrode. When the voltage is applied to the direction of the electrostatic force and the driving electrode, The displacement direction of the movable electrode is opposite. Therefore, in the present invention, even if a high-power signal is input to the signal conduction path, self-actuation can be prevented from occurring due to the influence. When a voltage is applied to the drive electrode and the movable electrode is separated from the fixed electrode, the electrostatic force generated between the movable electrode and the fixed electrode is sufficiently small, and the movable electrode is moved toward the second substrate side. Does not affect movement.

In the present invention, the signal conduction path is a path having a conductor filled in a through hole formed in the substrate. Therefore, the thickness of the wiring can be increased as compared with the conventional case where the wiring is formed in a substrate shape using a thin film forming technique. Therefore, ESR (Equivalent Series Resistance) of wiring can be reduced, and high Q can be achieved.

Furthermore, according to the present invention, the fixed electrode, the movable electrode, and the drive electrode are provided in a region sandwiched between the first and second substrates having insulation properties. Therefore, for example, when these electrodes are formed, a fixed frame, a movable electrode, and a drive electrode are sealed by the sealing frame by forming a sealing frame on the outer edge portions of the opposing surfaces of the first and second substrates. it can. This eliminates the need for a package formation step, and thus makes it possible to form the variable capacitance element at a low cost.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an explanatory cross-sectional view showing a main configuration of a first embodiment of a variable capacitance element according to the present invention. It is a perspective explanatory view showing the appearance composition of the 1st example. It is a typical perspective view which shows the movable part of the variable capacitance element of 1st Example. It is typical sectional drawing for demonstrating the manufacturing process by the side of the 1st board | substrate in the variable capacitance element of 1st Example, and the joining process of the 1st board | substrate side and the 2nd board | substrate side. It is typical sectional drawing for demonstrating the manufacturing process by the side of the 2nd board | substrate in the variable capacitance element of 1st Example. In the variable capacitance element of 1st Example, it is a schematic diagram for demonstrating the temperature characteristic at the time of forming a beam part and a stress provision part with a different material. In the variable capacitance element of 1st Example, it is a schematic diagram for demonstrating the temperature characteristic at the time of forming a beam part and a stress provision part with a different material. In the variable capacitance element of 1st Example, it is a schematic diagram for demonstrating the temperature characteristic at the time of forming a beam part and a stress provision part with the same material. FIG. 6 is an explanatory cross-sectional view showing the main configuration of a second embodiment of the variable capacitance element according to the present invention. It is a figure for demonstrating the external electrode of 2nd Example. In the example of the conventional variable capacitance element, it is a section explanatory view showing the state of switch off. FIG. 9B is a cross-sectional explanatory diagram illustrating a switch-on state of the variable capacitance element of FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 1st board | substrate 2 2nd board | substrate 3 1st through-hole 4 2nd through-hole 5 Fixed electrode 6 Beam part 7 Movable electrode 9 Drive electrode 10

Stopper

13,14

Copper

15,16

Sealing frame

17,18

Gold Membrane

21, 22, 23 External electrode

Embodiments according to the present invention will be described below with reference to the drawings.

FIG. 1 shows a first embodiment of a variable capacitance element according to the present invention by a cross-sectional view taken along line AA of FIG. FIG. 1 is a schematic cross-sectional view, omitting the

external electrodes

21, 22, and 23 shown in FIG.

As shown in FIG. 1, an insulating first substrate 1 and an insulating second substrate 2 are arranged with their

substrate surfaces

11 and 12 facing each other with a gap therebetween. The first and

second substrates

1 and 2 are both glass substrates. Each of the first and

second substrates

1 and 2 has a thickness of, for example, 300 μm. The first substrate 1 has one first through hole (via hole (VH)) 3 penetrating in the thickness direction of the substrate. The first through hole 3 is formed at a position corresponding to the signal output portion 33 (see FIG. 2) provided on the external electrode 21 side. The second substrate 2 has four second through holes (via holes) 4 penetrating in the thickness direction of the substrate. In FIG. 1, only two of the second through holes 4 are shown, but two second through holes 4 are similarly formed on the back side of the drawing. These second through holes 4 are formed at positions corresponding to the signal introduction part 34 (see FIG. 2). The first and second through

holes

3 and 4 are filled with copper (Cu) 13 and 14 as conductors, respectively.

On the counter substrate surface 11 of the first substrate 1, a copper fixed electrode 5 that is electrically connected to the copper 13 filled in the first through hole 3 is formed. The fixed electrode 5 is formed to a thickness of 5 μm. A stopper 10 as an insulator is provided on the front surface side (the lower surface side in this figure) of the fixed electrode 5. The stopper 10 is formed of a silicon oxide (SiO ₂ ) film provided on the surface side of the fixed electrode 5. On the counter substrate surface 11 of the first substrate 1, a sealing frame 15 having substantially the same height (thickness) as the fixed electrode 5 is formed on the outer peripheral side thereof. A gold film 17 for sealing is formed on the front end side of the sealing frame 15 with a thickness of about 0.5 μm.

On the other hand, on the counter substrate surface 12 of the second substrate 2, a movable electrode 7 is formed which is electrically connected to the copper 14 filled in the second through hole 4 via the beam portion 6. The movable electrode 7 is arranged to be spaced from the second substrate 2 while being lifted from the second substrate 2 while being urged to the fixed electrode 5 side by the beam portion 6. . The fixed electrode 5, the movable electrode 7 and the beam portion 6 are all made of copper having a thickness of about 10 μm. The movable electrode 7 is in contact with the fixed electrode 5 through the stopper 10 to form a capacitor (capacitor). On the surface of the beam portion 6, a stress applying portion 8 having a thickness of 1 μm for applying a tensile stress in the lifting direction from the second substrate 2 to the beam portion 6 is formed.

FIG. 3 shows a schematic perspective view of the movable electrode 7 and the beam portion 6. The movable electrode 7 and the beam portion 6 shown in the cross-sectional view of FIG. 1 show the BB cross section of FIG. A plurality of through holes 27 functioning as damping holes are formed in the movable electrode 7.

As shown in FIG. 1, on the counter substrate surface 12 of the second substrate 2, a drive electrode 9 that moves the movable electrode 7 toward the second substrate 2 is formed of platinum (Pt). An insulating film 19 made of silicon oxide is formed on the surface of the drive electrode 9. Further, a sealing frame 16 having substantially the same height as the movable electrode 7 is formed on the outer peripheral side of the counter substrate surface 12 of the second substrate 2. On the front end side of the sealing frame 16, a gold film 18 for sealing is formed with a thickness of about 0.5 μm. The gold film 18 and the gold film 17 are joined. External electrodes 23 for driving the drive electrodes 9 (see FIG. 2) are formed on the outer peripheral sides of the

gold films

17 and 18 and the sealing frames 15 and 16. In addition, the code | symbol 29 shown in FIG. 1 is the contact | adherence layer which consists of chromium films. This adhesion layer is for closely adhering the second substrate 2 made of glass and the sealing frame 16 made of copper.

In this embodiment, the movable electrode 7 and the movable electrode 7 are fixed by a path passing through the copper 14 filled in the second through hole 4, the beam portion 6, and the copper 13 filled in the first through hole 3. A signal conduction path is formed through the capacitor between the electrodes 5. As shown in FIG. 2, an RF (Radio Frequency) signal input external electrode 22 is formed on the surface of the second substrate 2 opposite to the counter substrate surface 12. On the other hand, an external electrode 21 for RF signal output is formed on the surface of the first substrate 1 opposite to the counter substrate surface 11. A signal lead-out portion 33 of the external electrode 21 is connected to the copper 13 in the first through hole 13, and a signal introduction portion 34 of the external electrode 22 is connected to the copper 14 in the second through hole 14.

In this embodiment, when no voltage is applied to the drive electrode 9, the movable electrode 7 is pressed against the fixed electrode 5 via the stopper 10, as shown in FIG. In this state, the distance between the fixed electrode 5 and the movable electrode 7 is narrow, and this distance is equal to the film thickness of the stopper 10. Therefore, the capacity of the fixed electrode 5 and the movable electrode is large. When a voltage is applied to the drive electrode 9, the movable electrode 7 moves toward the second substrate 2 and moves away from the fixed electrode 5. As a result, the distance between the fixed electrode 5 and the movable electrode 7 increases as the thickness of the

gold films

17 and 18 changes, and the capacitance between the fixed electrode 5 and the movable electrode 7 decreases.

Thus, in this embodiment, the capacitance between the fixed electrode 5 and the movable electrode 7 changes by turning on and off the voltage of the drive electrode 9.

In addition, a present Example is formed according to the arrow of a figure by the process as shown in FIG. 4, FIG. As shown in the uppermost stage of FIG. 4, on the first substrate 1 side, a first through hole 3 is formed, and the first through hole 3 is filled with copper 13. Next, as shown in the second stage of FIG. 4, the fixed electrode 5 and the sealing frame 15 are formed on the opposing substrate surface 11 of the first substrate 1 by selective plating of copper, and by CMP (Chemical Mechanical Polishing). Surface polishing is performed. Reference numeral 30 denotes a resist for selective plating. After that, as shown in the third stage of FIG. 4, the stopper 10 is formed on the surface (the lower surface in this figure) side of the fixed electrode 5, and the gold is formed on the tip side (the lower side in this figure) of the sealing frame 15. A film 17 is formed. Further, the selective plating resist 30 is removed.

On the other hand, as shown in the uppermost stage of FIG. 5, the second through holes 4 are also formed on the second substrate 2 side, and each second through hole 4 is filled with copper 14. Next, as shown in the second stage of FIG. 5, the drive electrode 9, the adhesion layer 29, and the insulating film 19 for preventing the drive unit short circuit are formed on the counter substrate surface 12 of the second substrate 2. Next, as shown in the third stage of FIG. 5, the sacrificial layer 24 is formed, and the movable electrode 7, the beam portion 6, and the sealing frame 16 are formed on the upper side of the sacrificial layer 24 by selective copper plating. . Reference numeral 31 denotes a resist for selective plating.

Then, as shown in the fourth row of FIG. 5, the selective plating resist 31 is removed and the gold film 18 is formed on the front end side (the upper side in this figure) of the sealing frame 16. Further, a stress applying portion 8 is formed on the surface of the beam portion 6. The stress applying portion 8 can be formed of, for example, a film that applies a stress that pulls the beam portion 6 due to an internal stress of platinum (platinum) or gold. When the stress applying portion 8 is formed simultaneously with the formation of the gold film 18, the variable capacitance element can be manufactured efficiently. Next, as shown in the lowermost stage of FIG. 5, the sacrificial layer 24 is removed by etching, and the beam application part 6 is lifted and lifted by the stress applying part 8, and the movable electrode 7 is lifted from the second substrate 2. State.

Then, as shown at the bottom of FIG. 4, the first substrate 1 and the second substrate 2 are opposed to each other, and the gold film 17 and the gold film 18 are bonded. As a result, the fixed electrode 5, the movable electrode 7, the beam portion 6, and the drive electrode 9 are sealed in the space between the first substrate 1 and the second substrate 2, and the movable electrode 7 is The portion 6 is pressed against the fixed electrode 5 side. Thereafter,

external electrodes

21, 22, and 23 are formed and cut by dicing to form variable capacitance elements.

The present embodiment is manufactured as described above, and has signal conduction

paths having copper

13 and 14 filled in the through

holes

3 and 4 of the first and

second substrates

1 and 2. Therefore, these thicknesses can be increased. For this reason, the present embodiment can reduce the wiring loss and increase the Q. Further, as described above, the displacement direction of the movable electrode 7 by the voltage application to the drive electrode 9 and the signal conduction path of the high-frequency signal. Since the direction of the electrostatic force generated when a voltage is applied to is reversed, self-actuation can be prevented.

Further, according to the present embodiment, the sealing frames 15 and 16 can be formed when the fixed electrode 5 is formed and when the drive electrode 7 and the beam portion 6 are formed. And since the fixed electrode 5, the movable electrode 7, and the drive electrode 9 can be sealed in the space sandwiched between the sealing frames 15 and 16 and the first and

second substrates

1 and 2, the package forming step can be performed. This is unnecessary, can prevent loss at the package forming portion, and can form the variable capacitance element at low cost.

Furthermore, in this embodiment, the movable electrode 7 and the beam portion 6 are made of copper, and the resistance of copper is low, so that ESR can be further reduced.

In addition, in forming the stress applying portion 8, the stress applying portion 8 can be formed of the same material as the beam portion 6. In this case, after forming the movable electrode 7 and the like by copper plating shown in the third stage of FIG. 5, a copper film as the stress applying portion 8 is formed on the surface of the beam portion 6 at a high temperature (for example, 80 ° C.). Form.

When the copper film is formed at a high temperature, the copper film on the second substrate 2 (the copper film for forming the beam portion 6, the movable electrode 7 and the like) is also raised to the same temperature, so that thermal expansion is attempted. The copper film on the second substrate 2 cannot be expanded because it is integrated with the second substrate 2 which is a glass substrate. On the other hand, the copper film formed at a high temperature is formed in a state of thermal expansion from the low temperature corresponding to the film formation temperature. Therefore, the film for the stress applying portion formed at a high temperature is thermally contracted when the temperature is lowered after the film formation, and when the sacrificial layer 24 is removed, the stress applying portion 8 applies a tensile stress to the beam portion 6. Thus, stress can be applied in the direction in which the movable electrode 7 is lifted. According to the experiment of the present inventor, for example, a 1 μm copper stress applying portion 8 is provided for a 10 μm beam portion 6 and the movable electrode 7 can be lifted by about 8 μm.

Further, when the stress applying portion 8 is formed of copper as described above, the following effects can be obtained. That is, when the stress applying portion 8 is formed of gold, platinum, or the like, which is a material different from copper forming the beam portion 6, the beam according to the temperature change due to the difference in linear expansion coefficient between the beam portion 6 and the stress applying portion 8. The warping of the portion 6 changes as shown by the broken lines in FIGS. 6a and 6b. Then, the movable electrode 7 provided on the distal end side of the beam portion 6 moves up and down as shown by the arrow in FIG. 6b, and the force pressing the movable electrode 7 toward the fixed electrode 5 side by the beam portion 6 varies depending on the temperature. End up.

On the other hand, as shown in FIG. 6 c, when the stress applying portion 8 is formed of the same material as the copper forming the beam portion 6, the linear expansion coefficient of the beam portion 6 and the stress applying portion 8 is equal. Therefore, the beam portion 6 does not go up and down. Therefore, there is an advantage that the force pressing the movable electrode 7 toward the fixed electrode 5 by the beam portion 6 can be made constant regardless of the temperature. In other words, even when a temperature change occurs, a change in the force that urges the movable electrode 7 toward the fixed electrode 5 by the beam portion 6 hardly occurs. Therefore, the temperature dependence of the capacitance between the fixed electrode 5 and the movable electrode 7 can be reduced. Therefore, when the stress applying portion 8 is formed of the same material as the copper forming the beam portion 6, the applied voltage when the same operation is performed in a wide temperature range by the variable capacitance element can be reduced.

Next, a second embodiment of the variable capacitance element according to the present invention will be described. In the description of the second embodiment, parts having the same names as those in the first embodiment are denoted by the same reference numerals, and redundant description thereof is omitted or simplified.

FIG. 7 is a schematic cross-sectional view showing the variable capacitance element of the second embodiment. As shown in the figure, in the second embodiment, a first through-hole 3 and a second through-hole 4 that penetrate in the thickness direction of the substrate are formed in the first substrate 1. These first and second through

holes

3 and 4 are filled with

copper

13 and 14, respectively.

As shown in FIG. 8, the RF signal output external electrode 22 and the RF signal input external electrode 21 are spaced from each other on the surface 38 opposite to the counter substrate surface 11 of the first substrate 1. Is provided. Further, a signal introducing unit 34 and a signal deriving unit 33 are provided. Further, on the outer peripheral side of the sealing frames 15 and 17, an external electrode 23 for driving the drive electrode 9 is provided (not shown) as in the first embodiment. The external electrode 23 is provided on the surface opposite to the counter substrate surface 11 of the first substrate 1 as shown by a broken line in FIG. 8, and the drive electrode 9 is shown as a broken line A in FIG. It is also possible to conduct to the external electrode 23 from the first substrate 1 side.

The copper 13 filled in the first through-hole 3 is conducted to the signal introducing portion 33, and the copper 14 filled in the second through-hole 4 is conducted to the signal deriving portion 34. Further, the counter substrate surface 11 of the first substrate 1 is filled in the first fixed electrode 5 (5a) conducting to the copper 13 filled in the first through hole 3 and the second through hole 4. A second fixed electrode 5 (5b) that is electrically connected to the formed copper 14 is formed. A movable electrode 7 is formed on the counter substrate surface 12 of the second substrate 2 via a beam portion 6.

In the second embodiment, when no voltage is applied to the drive electrode 9, the movable electrode 7 is pressed against the first and second

fixed electrodes

5a and 5b via the stopper 10. On the other hand, when a voltage is applied to the drive electrode 9, the movable electrode 7 moves to the second substrate side 2 and moves away from the first and second

fixed electrodes

5a and 5b. By such an operation of the movable electrode 7, the capacitance between the fixed electrode 5 and the movable electrode 7 changes.

In the second embodiment, the copper 13 filled in the first through-hole 3, the capacitor between the movable electrode 7 and the first fixed electrode 5a, and the movable electrode 7 and the second fixed electrode 5b are used. A signal conduction path is formed by a path passing through the capacitor portion between the first through hole 4 and the copper 14 filled in the second through hole 4. In the second embodiment, the capacitor (capacitor) between the movable electrode 7 and the first fixed electrode 5a and the capacitor between the movable electrode 7 and the second fixed electrode 5b are connected in series. It is made.

Other configurations of the second embodiment are the same as those of the first embodiment. In the second embodiment, the first and second through

holes

3 and 4 are formed and the

copper

13 and 14 filled in the through

holes

3 and 4 are connected to the first and second through holes. Second

fixed electrodes

5a and 5b are formed. Otherwise, the second embodiment is manufactured in the same manner as the first embodiment. Further, as described above, the second embodiment operates in substantially the same manner as the first embodiment, and can achieve the same effects as the first embodiment.

The present invention is not limited to the above-described embodiments, and various embodiments can be adopted. For example, the formation pattern of the movable electrode 7, the beam portion 6 and the like is not limited to the pattern shown in FIG. 3, and is appropriately set.

Further, although the conductors filling the movable electrode 7, the beam portion 6, and the first and second through

holes

3 and 4 are all made of copper, these are not necessarily copper. That is, conductors such as silver (Ag) and gold (Au) other than copper can be appropriately filled in the first and second through

holes

3 and 4. The drive electrode 9 is also formed of a suitable conductor.

Further, in each of the above embodiments, the first and

second substrates

1 and 2 are both glass substrates. However, the first and

second substrates

1 and 2 may be insulating substrates made of other insulating materials such as ceramic, alumina, silicon, and gallium arsenide (GaAs). Furthermore, an insulating substrate formed by coating the surface of a conductive material with an insulating material may be used.

Further, in each of the above embodiments, the stopper 10 which is an insulator is provided on the surface side of the fixed electrode 5. However, the insulator may be provided on the surface side of the movable electrode 7 (surface facing the fixed electrode), or may be provided on the surface facing the counterpart electrode in both the fixed electrode 5 and the movable electrode 7. .

By providing a configuration unique to the present invention, high Q is possible, self-actuation does not occur at the time of signal input, and an inexpensive variable capacitance element can be formed, so that it can be applied to various electric circuits as a switch or the like. It is possible.

Claims

An insulating first substrate and an insulating second substrate are disposed with their substrate surfaces facing each other with a space therebetween, and the first substrate penetrates in the thickness direction of the substrate. The second substrate is formed with second through holes penetrating in the thickness direction of the substrate, and the first and second through holes are filled with a conductor, respectively. A fixed electrode is formed on the surface of the counter substrate of the first substrate and is electrically connected to the conductor filled in the first through hole. The surface of the counter substrate of the second substrate is formed on the second through hole. A movable electrode that conducts through the beam portion is formed on the filled conductor, and the movable electrode is urged toward the fixed electrode by the beam portion and floats from the second substrate. It is arranged with a distance from the second substrate, and there are few movable electrodes and fixed electrodes. The other is provided with an insulator on the surface facing the counterpart electrode, and the second substrate is provided with a drive electrode that draws and moves the movable electrode toward the second substrate. When no voltage is applied to the electrode, the movable electrode is pressed against the fixed electrode through the insulator, and when a voltage is applied to the drive electrode, the movable electrode moves to the second substrate side and The capacitance between the fixed electrode and the movable electrode is changed by moving in a direction away from the fixed electrode, and the conductor filled in the second through hole, the beam portion, and the first A variable-capacitance element characterized in that a signal conduction path through a capacitor portion between the movable electrode and the fixed electrode is formed by a path passing through a conductor filled in the through hole.
An insulating first substrate and an insulating second substrate are disposed with their substrate surfaces facing each other with a space therebetween, and the first substrate penetrates in the thickness direction of the substrate. A hole and a second through hole are formed, and each of the first and second through holes is filled with a conductor, and the first through hole is formed on the counter substrate surface of the first substrate. The counter substrate of the second substrate is formed with a first fixed electrode conducting to the conductor filled in the hole and a second fixed electrode conducting to the conductor filled in the second through-hole. A movable electrode is formed on the surface via a beam portion, and the movable electrode is lifted from the second substrate in a state of being biased toward the fixed electrode side by the beam portion and the second substrate. Arranged at an interval, and at least one of the movable electrode and the fixed electrode has a counterpart electrode An insulator is provided on the opposite surface, and a driving electrode is formed on the second substrate to draw and move the movable electrode toward the second substrate. When no voltage is applied to the driving electrode The movable electrode is pressed against the first and second fixed electrodes through the insulator, and when a voltage is applied to the drive electrode, the movable electrode moves to the second substrate side and the first and second The capacitance between the fixed electrode and the movable electrode is changed by moving in a direction away from the second fixed electrode, and the conductor filled in the first through hole, and the movable electrode And the first fixed electrode, the capacitive part between the movable electrode and the second fixed electrode, and a path through the conductor filled in the second through hole. Variable volume characterized by the formation of a path Element.
3. The variable capacitance element according to claim 1, wherein the movable electrode and the beam portion are made of copper.
On the surface of the beam portion, there is formed a stress applying portion for applying a tensile stress in the lifting direction from the second substrate to the beam portion, and the stress applying portion is formed of the same material as the beam portion. The variable capacitance element according to claim 1, wherein the variable capacitance element is provided.