JP3368304B2 - Electrostatic micro relay - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrostatic micro relay, and more particularly to an electrostatic micro relay that can be manufactured by a semiconductor process.

[0002]

2. Description of the Related Art Conventionally, as an electrostatic micro relay, for example, as shown in FIG. 7, there is one in which an actuator 2 made of a silicon wafer is mounted on a base 1 made of a glass wafer. That is, the base 1 is provided with a fixed electrode 3 at the center of the upper surface thereof, and a pair of fixed contacts 4 and 5 (the fixed contact 5 on the back side is not shown) is arranged in parallel at one edge portion thereof. On the other hand, the actuator 2 has a cantilever-shaped movable electrode 7 extending laterally from the upper edge of the anchor 6 standing on the base 1. A movable contact 9 is provided at the free end of the insulating film 8 formed on the lower surface of the movable electrode 7, and faces the fixed contacts 4 and 5 of the base 1 so as to be contactable and separable.

[0003]

However, according to the above-mentioned electrostatic micro relay, even if the movable electrode 7 is attracted and attracted by the electrostatic attraction of the fixed electrode 3 with respect to the movable electrode 7, the movable electrode 7 can be attracted. A movable contact 9 is arranged on the lower surface of the free end. Therefore, due to the lever principle, the load applied to the movable contact 9 on the fixed contacts 4 and 5 is small, and the contact pressure is low. As a result, the movable contact 9 is likely to be separated from the fixed contacts 4 and 5 due to external vibration or impact force, and malfunction is likely to occur. Further, since the fixed electrode 3 attracts the vicinity of the base portion of the movable electrode 7 rather than the movable contact 9, there is a problem that a high drive voltage is required when the movable electrode 7 is attracted and displaced by electrostatic attraction.

In view of the above problems, it is an object of the present invention to provide an electrostatic microrelay that can be driven with a low driving voltage and can obtain a desired contact pressure.

[0005]

In order to achieve the above object, an electrostatic micro relay according to the present invention has a voltage applied between a fixed electrode provided on a base and a movable electrode of an actuator fixed on the upper surface of the base. In the electrostatic micro relay that drives the movable electrode by an electrostatic attractive force generated by applying the electric field to open and close an electric circuit by bringing the movable contact provided in the actuator into contact with and separated from the fixed contact provided in the base, While forming fixed electrodes on the upper surface and arranging fixed contacts around the fixed electrodes, an actuator in which a thin film movable electrode is extended from the upper edge of the frame body is provided outside the fixed contacts on the upper surface of the base. The movable electrode of the actuator is opposed to the fixed electrode so that the movable electrode can come into contact with and separate from the fixed electrode, and the movable contact provided on the lower surface of the movable electrode is fixed to the fixed electrode. Are constituted was separable therefrom opposite the contacts.

Further, the movable electrode is driven by an electrostatic attraction generated by applying a voltage between the fixed electrode provided on the base and the movable electrode of the actuator fixed on the upper surface of the base, and the movable electrode is provided on the base. An electrostatic micro relay that opens and closes an electric circuit by contacting and separating a fixed contact with a movable contact provided in the actuator, and an anchor having an actuator having a thin plate beam portion having a substantially cross-shaped plan view at an end portion of the thin plate beam portion. Is fixed upright on the upper surface of the base, the movable electrode extending laterally from the edge portion of the thin plate beam portion, while facing the fixed electrode provided on the upper surface of the base so as to be contactable and separable, The movable contact provided in the center of the lower surface of the thin plate beam portion may be opposed to the fixed contact of the base so as to be contactable and separable.

Further, the movable electrode is driven by the electrostatic attraction generated by applying a voltage between the fixed electrode provided on the base and the movable electrode of the actuator fixed on the upper surface of the base, and the movable electrode is provided on the base. In an electrostatic micro relay that opens and closes an electric circuit by contacting and separating a fixed contact with a movable contact provided in the actuator, an actuator having a straight thin plate beam portion and an anchor provided at an end of the thin plate beam portion are used as the base. The thin plate beam is fixed upright on the upper surface of the thin plate beam, and the movable electrodes extending laterally from both side edges of the thin plate beam portion are made to face the fixed electrode provided on the upper surface of the base so that they can be separated from each other. The movable contact provided in the center of the lower surface of the portion may face the fixed contact of the base so that the movable contact can come into contact with and separate from the fixed contact.

The movable electrode may be thinner than the thin plate beam portion. Further, an insulating film may be formed on at least one of the facing surfaces of the movable electrode and the fixed electrode.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION Next, an embodiment of the present invention will be described with reference to the accompanying drawings of FIGS. As shown in FIGS. 1 to 4, the electrostatic micro relay according to the first embodiment has an actuator 20 integrated on the upper surface of a base 10 made of a glass substrate 11a.

The base 10 is provided with a circular fixed electrode 12 at the center of the upper surface of a glass substrate 11a and a concentric fixed contact 13 around the circular fixed electrode 12. The fixed electrode 12 and the fixed contact 13 are connected to connection pads (not shown) via printed wiring (not shown).

The actuator 20 is the base 1
An anchor 21, which is an annular frame, is joined and integrated to the upper surface edge portion of 0. A thin film movable electrode 22 extends from the upper edge of the anchor 21. An annular movable contact 24 is formed on the lower surface of the movable electrode 22 via an insulating film 23.
Is formed, and faces the fixed contact 13 so that the fixed contact 13 can be contacted and separated. If a silicon oxide film having a relative permittivity of 3 to 4 or a silicon nitride film having a relative permittivity of 7 to 8 is used as the insulating film 23, a large electrostatic attractive force can be obtained and a contact load can be increased.

Next, a method of manufacturing the electrostatic micro relay having the above-mentioned structure will be described. First, as shown in FIG.
The fixed electrode 12 and the fixed contact 13 are formed by vapor-depositing Au on a glass substrate 11a such as Pyrex which becomes the base 10 and patterning. Further, at the same time, a printed wiring and a connection pad (not shown) are formed.

On the other hand, as shown in FIG. 3, after the silicon wafer 25 to be the actuator 20 is oxidized and patterned, a cavity 26 having a depth of 5 μm is formed by etching with TMAH. Then, the cavity 26
A thermal oxide film is formed on the ceiling surface of and patterned to form an insulating film 23 in the cavity 26. Then, Cr,
An annular movable contact 24 is formed by sequentially depositing Ni and Au and patterning.

Then, the silicon wafer 25 is joined to the base 10 by anodic bonding at a temperature of 400 ° C. and a voltage of 400 V for 1 hour. Then, T
Thin the silicon wafer 25 with MAH to a thickness of 10
The movable electrode 22 having a thin film of μm is formed.

The base 10 is not limited to the glass substrate 11a alone, but may be formed of a single crystal silicon substrate having at least its upper surface covered with an insulating film.

According to this embodiment, the actuator 20
Since the movable electrode 22 is formed so as to be bilaterally symmetric while being formed entirely from a silicon wafer, the movable electrode 22 is unlikely to be deformed. As a result, inoperability,
There are advantages in that variations in operating characteristics can be effectively prevented and smooth operating characteristics can be secured.

Next, the operation of the electrostatic micro relay having the above structure will be described. First, when no voltage is applied between the fixed electrode 12 and the movable electrode 22, the fixed electrode 12
And the movable electrode 22 remain parallel to each other, and the movable contact 24 is separated from the fixed contact 13 (FIG. 1B).

Next, when a voltage is applied between the fixed electrode 12 and the movable electrode 22, the movable electrode 22 is attracted to the fixed electrode 12 by the electrostatic attractive force generated between the electrodes 12 and 22. Therefore, the central portion of the movable electrode 22 sinks and the movable electrode 22 approaches the fixed electrode 12. As a result, since the gap is narrowed, the movable electrode 22 is attracted by the fixed electrode 12 by a stronger electrostatic attraction, and the movable contact 24 comes into contact with the fixed contact 13, and then the movable electrode 22 is fixed via the insulating film 23. Adsorb to 12.

When the application of the above voltage is stopped,
The movable electrode 22 is separated from the fixed electrode 12 by the spring force of the movable electrode 22, the movable contact 24 is separated from the fixed contact 13, and the movable electrode 22 is returned to its original state.

As shown in FIG. 5, the electrostatic microrelay according to the second embodiment comprises a base 10 made of a glass wafer 11a and an actuator 20, as in the first embodiment. The actuator 20 includes an anchor 21, which is a flat rectangular frame, and a thin plate beam portion 2 having a substantially cross shape.
It is a bridge of 7. Furthermore, this thin plate beam portion 27
Is a substantially square movable electrode 28 from one side edge in the same direction.
Have been extended respectively. The movable contact 24 is formed in the center of the lower surface of the thin plate beam portion 27 via an insulating film (not shown).
Is provided. The movable electrode 28 is thinner than the thin plate beam portion 27.

On the other hand, the base 10 made of the glass wafer 11a has fixed electrodes 12 and fixed contacts (not shown) formed at positions corresponding to the movable electrodes 28 and the movable contacts 24. Further, the fixed electrode 12 and the fixed contact are electrically connected to the connection pad via a printed wiring (not shown).

Next, a method of manufacturing the electrostatic micro relay according to the second embodiment will be described. The base 10 forms four fixed electrodes 12 and fixed contacts by vapor-depositing Au on a glass substrate 11a such as Pyrex and patterning it. At the same time, a printed wiring and a connection pad (not shown) are formed and electrically connected.

On the other hand, after the lower surface of the SOI silicon wafer to be the actuator 20 is oxidized and patterned,
A cavity is formed by etching with TMAH. Then, a thermal oxide film is formed on the ceiling surface of the cavity and patterned to form an insulating film in the cavity. Next, the movable contact 24 is formed by sequentially depositing Cr, Ni, and Au and patterning.

Then, the SOI silicon wafer is bonded and integrated with the base 10 by anodic bonding. Then TM
The silicon wafer is etched by AH to the oxide film and thinned. Further, after removing the oxide film with a fluorine-based etching solution, die-cutting etching is performed by dry etching using RIE or the like to form a bent slit to cut out the thin plate beam portion 27 and the movable electrode 28, and the actuator 20 is completed. To do.

Next, the operation of the second embodiment will be described. First, when no voltage is applied between the fixed electrode 12 and the movable electrode 28, the fixed electrode 12 and the movable electrode 28 are parallel to each other, and the movable contact 24 is separated from the fixed contact.

Next, when a voltage is applied between the fixed electrode 12 and the movable electrode 28, the movable electrode 28 is attracted to the fixed electrode 12 by the electrostatic attractive force generated between the electrodes 12 and 28. For this reason, the free end of the movable electrode 28 approaches the fixed electrode 12, the electrostatic attraction is further increased, and the movable electrode 28 is attracted with a stronger attraction force. As a result, after the thin plate beam portion 27 bends and the movable contact 24 comes into contact with the fixed contact, the movable electrode 28 is adsorbed to the fixed electrode 12 via the insulating film.

When the application of the above voltage is stopped,
After the movable electrode 28 is separated from the fixed electrode 12 by the spring force of the thin plate beam portion 27, the movable contact 24 is separated from the fixed contact, and the movable electrode 28 returns to its original state by its own spring force.

In the third embodiment, as shown in FIG. 6, an actuator 20 made of a silicon wafer is joined and integrated with a base 10 made of a silicon wafer 11b. That is, the base 10 is a silicon wafer 11
An insulating film 14 is formed on the upper surface of b, and a pair of fixed contacts 13 and 15 (the fixed contact 15 on the back side is not shown) is arranged on the upper surface. Further, a pair of fixed electrodes 12, 12 are provided with the fixed contacts 13, 15 interposed therebetween.

The actuator 20 is composed of a thin plate beam portion 27 whose both ends are bridged to the upper edge portions of a pair of anchors 21 and 21 erected on the upper surface of the base 10, and a movable contact 24 is provided at the center of the lower surface. There is. Further, movable electrodes 28 extend laterally from both side edge portions of the thin plate beam portion 27 and face the fixed electrode 12 so that they can come into contact with and separate from the fixed electrode 12. The movable electrode 28 is thinner than the thin plate beam portion 27.

A method of manufacturing the electrostatic micro relay according to the third embodiment will be described. First, the insulating film 14 is formed by oxidizing and patterning the silicon wafer 11b serving as the base 10. And Cr, Ni, Au
Are sequentially vapor-deposited and patterned to form the fixed electrode 12 and the fixed contacts 13 and 15, and at the same time, a printed wiring and a connection pad (not shown) are formed.

On the other hand, after the silicon wafer to be the actuator 20 is oxidized and patterned, a cavity is formed by TMAH. Then, a thermal oxide film is formed and patterned to form an insulating film 23 on the ceiling surface of the cavity. Then, Cr, Ni, and Au are sequentially deposited and patterned to form the movable contact 24.

Next, low temperature glass is applied to the bonding surface of the silicon wafer to be the base 10 and the actuator 20 and heated at a temperature of 400 ° C. for 1 hour.
Join together. And the actuator 20 with KOH
The actuator 20 is completed by thinning a silicon wafer to be the above and by cutting out the thin plate beam portion 27 and the movable electrode 28.

Next, the operation of the third embodiment will be described. First, when no voltage is applied between the fixed electrode 12 and the movable electrode 28, the fixed electrode 12 and the movable electrode 28 face each other in parallel, and the movable contact 24 is separated from the fixed contacts 13 and 15.

Then, the fixed electrode 12 and the movable electrode 28
When a voltage is applied between them, the movable electrode 28 is attracted to the fixed electrode 12 by the electrostatic attraction generated between the electrodes 12 and 28. For this reason, the free end of the movable electrode 28 approaches the fixed electrode 12, the electrostatic attraction is further increased, and the movable electrode 28 is attracted with a stronger attraction force. As a result,
The thin plate beam portion 27 bends to move the movable contact 24 to the fixed contact 13,
After coming into contact with 15, the entire movable electrode 28 is adsorbed to the fixed electrode 12 via the insulating film 23.

When the application of the above voltage is stopped,
After the movable electrode 28 is separated from the fixed electrode 12 by the spring force of the thin plate beam portion 27, the movable contact 24 is fixed to the fixed contacts 13 and 15.
The movable electrode 28 returns to its original state by its own spring force.

[0036]

As is apparent from the above description, according to the electrostatic micro relay of the first aspect of the present invention, when a voltage is applied between the fixed electrode and the movable electrode, the center of the thin film movable electrode is reduced. Is attracted to the fixed electrode by electrostatic attraction, and the movable contact provided near the base of the movable electrode comes into contact with the fixed contact. Therefore, since the central portion of the movable electrode, which is most easily deformed, is attracted by electrostatic attraction, an electrostatic micro relay capable of opening and closing the contacts with a low driving voltage can be obtained. Further, since the movable contact is arranged at the base of the movable electrode, the electrostatic attraction can be effectively utilized by the lever principle. Therefore, an electrostatic micro relay having a large contact load and less likely to malfunction can be obtained.

According to the second and third aspects, when a voltage is applied between the fixed electrode and the movable electrode, an electrostatic attractive force is generated and the movable electrode bends. Therefore, the free end of the movable electrode approaches the fixed electrode, and the movable electrode is attracted by a larger electrostatic attraction. As a result, the thin plate beam portion bends and the movable contact comes into contact with the fixed contact, so that an electrostatic micro relay that can be driven with a low drive voltage is obtained. According to claims 2 and 3,
In each case, the movable contact is arranged at the center of the thin plate beam portion and near the base of the movable electrode. Therefore, the electrostatic attractive force can be effectively utilized, and an electrostatic micro relay having a large contact pressure can be obtained.

According to the fourth aspect, the movable electrode is thinner than the thin plate beam portion. Therefore, when a voltage is applied between the fixed electrode and the movable electrode, the movable electrode bends due to electrostatic attraction. As a result, the free end of the movable electrode approaches the fixed electrode, the movable electrode is attracted by a stronger electrostatic attraction, and the movable contact comes into contact with the fixed contact. Therefore, an electrostatic micro relay that can be driven with a lower drive voltage than that of the conventional example can be obtained. Claim 5
According to this, an insulating film is formed on at least one of the facing surfaces of the fixed electrode and the movable electrode.
For this reason, the fixed electrode and the movable electrode do not come into direct contact with each other, and both are attracted by a large electrostatic attractive force while leaving the thickness of the insulating film, so that an electrostatic micro relay having a desired contact load can be obtained. effective.

[Brief description of drawings]

1A and 1B show an electrostatic micro relay according to a first embodiment of the present invention, in which FIG. 1A is a plan view of a base and FIG.
Is a sectional view.

FIG. 2 is a base process flow according to the first embodiment.

FIG. 3 is a process flow of the actuator according to the first embodiment.

FIG. 4 is a process flow showing joining of a base and an actuator.

FIG. 5 is a plan view showing an electrostatic micro relay according to a second embodiment of the present invention.

6A and 6B show an electrostatic micro relay according to a third embodiment of the present invention, in which FIG. 6A is a plan view of a base and FIG.
Is a sectional view.

FIG. 7 is a sectional view of an electrostatic micro relay according to a conventional example.

[Explanation of symbols]

10 ... Base, 12 ... Fixed electrode, 13, 15 ... Fixed contact, 14 ... Insulating film, 20 ... Actuator, 21 ... Anchor, 22 ... Movable electrode, 23 ... Insulating film, 24 ... Movable contact,
27 ... Thin plate beam part, 28 ... Movable electrode.

─────────────────────────────────────────────────── ─── Continuation of the front page (56) Reference JP-A-2-100224 (JP, A) JP-A-8-235997 (JP, A) JP-A-8-227646 (JP, A) JP-A-8- 213803 (JP, A) JP-A-9-213191 (JP, A) JP-A-10-162713 (JP, A) Actual development 3-53731 (JP, U) (58) Fields investigated (Int.Cl. ⁷ , DB name) H01H 59/00

Claims (5)

(57) [Claims] 1. A movable electrode is driven by an electrostatic attraction generated by applying a voltage between a fixed electrode provided on a base and a movable electrode of an actuator fixed on the upper surface of the base,
In an electrostatic micro relay that opens and closes an electric circuit by bringing a movable contact provided in the actuator into contact with and separated from a fixed contact provided in the base, a fixed electrode is formed on the upper surface of the base, and a fixed contact is arranged around the fixed electrode. On the other hand, an actuator in which a thin film movable electrode is extended from the upper edge of the frame is fixed by joining the frame to the outside of the fixed contact on the upper surface of the base, and fixing the movable electrode of the actuator to the fixed electrode. And a movable contact provided on a lower surface of the movable electrode so as to face and separate from the fixed contact. 2. The movable electrode is driven by an electrostatic attraction generated by applying a voltage between a fixed electrode provided on the base and a movable electrode of an actuator fixed on the upper surface of the base,
In an electrostatic micro relay that opens and closes an electric circuit by bringing a movable contact provided in the actuator into contact with and separated from a fixed contact provided in the base, an actuator having a thin plate beam portion having a substantially cross shape in a plane,
An anchor provided at an end portion of the thin plate beam portion is erected and fixed on the upper surface of the base, and a movable electrode extending laterally from an edge portion of the thin plate beam portion is provided on the upper surface of the base. An electrostatic micro-relay, wherein a movable contact provided in the center of the lower surface of the thin plate beam portion is faced to a fixed contact of the base so as to be able to come into contact with and separated from the fixed electrode. 3. The movable electrode is driven by an electrostatic attractive force generated by applying a voltage between a fixed electrode provided on the base and a movable electrode of an actuator fixed on the upper surface of the base,
In an electrostatic micro relay that opens and closes an electric circuit by bringing a movable contact provided in the actuator into contact with and separated from a fixed contact provided in the base, an actuator composed of a straight thin plate beam portion is provided at an end portion of the thin plate beam portion. The anchor is erected on the upper surface of the base and fixed, and the movable electrode extending laterally from both side edges of the thin plate beam portion is opposed to the fixed electrode provided on the upper surface of the base so as to be contactable and separable. At the same time, an electrostatic micro relay characterized in that a movable contact provided at the center of the lower surface of the thin plate beam portion is opposed to a fixed contact of the base so that the movable contact can be contacted and separated. 4. The electrostatic micro relay according to claim 2, wherein the movable electrode is thinner than the thin plate beam portion. 5. The electrostatic micro relay according to any one of claims 1 to 4, wherein an insulating film is formed on at least one of the facing surfaces of the movable electrode and the fixed electrode. .