JPH11260178A - Contact for electric-circuit switching device and electric-circuit switching device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent formation of a bad-conductor layer on a contact surface, achieve a low contact resistance property, and hence miniaturize a device and reduce power consumption, by devising on material quality of a layer lying between a contact layer and a substrate. SOLUTION: In the event that a contact layer 3 formed on an insulating or conductive substrate 1 is composed of a noble metal or a platinum group metal, or of an alloy of a noble metal or of a platinum group metal, a contact for an electric-circuit switching device for switching an electric circuit depending on whether mechanical contact exists or not, is formed by interposing, as an adhesive layer 2, between the substrate 1 and the contact layer 3, a metallic oxide layer having, as main constituent, a metallic oxide of a platinum group metal.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to at least one pair of contacts for an electric circuit switching device which opens and closes an electric circuit by mechanically contacting and opening, and an electric circuit switching device using the same. In particular, a contact and an electric circuit switch for an electric circuit switch that can be applied to a relay that opens and closes an electric contact by an external electric input, for example, a small and low power consumption type relay that uses a small driving force as a power source for opening and closing the electric contact. Related to the device.

[0002]

2. Description of the Related Art Conventionally, as an electric circuit switching device that opens and closes an electric circuit by contacting and releasing a mechanical electric contact,
BACKGROUND ART Electromagnetic relays using electromagnets, reed relays, relays using piezoelectric bimorphs, electrostatic relays, and the like are known.

[0003] Such an electric circuit switchgear has a higher input-output (between a control input for opening and closing a circuit and a signal to be turned on and off) than an electric circuit switchgear using a semiconductor such as a thyristor or MOSFET. It has very excellent characteristics such as insulation, insulation when a circuit is opened, and low resistance (insertion loss) when the circuit is closed, and has been widely used.

[0004] Most commonly used electromagnetic relays use an attractive force of an electromagnet as a driving force, drive a movable contact, and make and break contact with a fixed contact, thereby establishing an electrical connection between the two contacts. It is a thing that opens and closes.

A device that mechanically opens and closes an electric circuit by contacting and opening an electric contact is basically the same as this electromagnetic relay except for the difference in the method used as its driving force.
An electric circuit is opened and closed depending on the presence or absence of mechanical contact between the contacts. In any device, the characteristics of the contact surface influence electrical characteristics such as contact resistance when the contacts are closed. For example, when a base metal is used for a contact, an insulating or low-conductive oxide or the like is formed on the contact surface depending on the use atmosphere, resulting in poor contact resistance (OMRON Corporation Catalog 12th Edition, Catalog No. SAAO- 005, 1994
June 1998, p. 982, 983).

For this reason, as a contact material, a noble metal such as gold, platinum, silver, iridium or a platinum group metal or an alloy thereof is used, in which a defective conductor such as an insulating oxide is difficult to be formed.

Further, by applying a sufficiently large contact pressure when the movable contact and the fixed contact are brought into contact with each other, a defective conductor layer on the contact surface is mechanically broken and removed, thereby preventing a contact resistance defect.

Further, in order to electrically destroy the defective conductor layer, the current flowing through the contact must be at least a constant value in practical use, and this is defined as the minimum applicable load.

[0009]

The causes of the defective conductor layer formed on the contact surface include (1) a defective conductor layer formed by a reaction between a contact material and a contaminant gas in a surrounding atmosphere during use; (2) Contact material (and impurities therein)
Oxide-defective conductor layer due to the reaction between oxygen and a surrounding atmosphere during use or oxygen during the manufacturing process.

As the defective conductor layer belonging to (1), for example, Ag formed between H ₂ S, SO ₂ gas and silver-based contact material is used.
₂ S layer, organic gas and platinum, the polymer layer formed by palladium contact material, nitrogen oxides and H ₂ S and gold-based ammonium is formed by the contact material and the like are known.

However, the defective conductor layer belonging to (1) is a problem that can be solved if the contacts are hermetically sealed in a clean atmosphere, and a sufficient countermeasure is conventionally taken by a method such as hermetic sealing.

As the defective conductor layer belonging to (2),
(A) an oxide of a contact material; (b) an oxide of an impurity contained in the contact material; and (c) an oxide of an impurity which is included in the contact material due to diffusion of peripheral materials during the manufacturing process or use thereof. , And the like.

Among them, the oxides (a) and (b) are usually of sufficiently high purity such as gold, platinum, iridium or other noble metal or platinum group which do not cause oxidation at the operating temperature or the heat history in the manufacturing process. No problem arises if sufficient production process control is performed using the above metals and alloys thereof.

However, it is extremely difficult to avoid the diffusion of the material around the contact (c) and the formation of its oxide layer during long-term use.

The base portion on which the contacts are held is usually made of an insulating material or a base metal material. If these materials are in direct contact with the noble metal or platinum group metal contact part,
The noble metal or platinum group metal easily diffuses from inside the contact to the contact surface, and eventually forms an oxide layer which is a defective conductor on the contact surface.

Further, when a noble metal or a platinum group metal is used as a contact material, since the noble metal or a platinum group metal is inactive, even if it is directly bonded to an insulator material or a base metal material serving as a base of the contact, sufficient adhesive strength is obtained. I can't get it.

Therefore, in order to form a contact having sufficient adhesive strength using a noble metal or a platinum group metal material in practice, when the base is a metal material, the contact between the base and the noble metal or the platinum group metal is made. If this is not possible or if it is not possible, it is necessary to insert a mutually diffusible or reactive intermediate layer, ie an adhesive layer.

As this adhesive layer, a base metal such as Cr, Ti or the like is used. These adhesive layers and the interdiffusion layers themselves diffuse to the surface of the contact and remove the oxide layer which is a defective conductor. Will form.

Usually, in order to avoid such a diffusion problem, a diffusion preventing layer such as Ni is inserted between a noble metal or a platinum group metal as a contact material and a base metal or an insulator to diffuse the noble metal or the platinum group metal. Prevention can be considered.

However, since the diffusion preventing layer itself is a base metal material, the diffusion preventing layer itself partially diffuses in the noble metal or platinum group metal material when used for a long time or when a temperature load is applied, so that the noble metal or platinum group metal material is not diffused. An oxide layer which is a defective conductor is formed on the surface of the platinum group metal contact.

Therefore, no matter what the conventional configuration is,
The formation of a defective conductor layer formed on the contact surface is inevitable,
Since contact resistance failure is likely to occur, it is necessary to use a contact made of a precious metal or platinum group metal material, and to destroy the defective conductor layer by applying a sufficiently large mechanical pressure and a sufficient contact current. Met.

Therefore, in order to drive the movable contact as a relay, an actuator capable of generating a sufficient mechanical pressure was required.

For example, in the case of an electromagnetic relay, an actuator using an electromagnet is used as a driving force source. However, a large object must be used as the electromagnet and a sufficient coil current must flow.

This means that the size of the electric circuit switchgear can be reduced,
This is a major obstacle in reducing power consumption, and in the trend of miniaturization and low power consumption of electronic components, electromagnetic relays have become remarkably large components and large power consumption.

Further, since there is a lower limit current value (minimum applicable load) necessary for electrically breaking the defective conductor layer, there is a problem when a conventional electric circuit switch is used for switching a small signal or the like. This is a component that is difficult to use in current electronic circuits with low power consumption.

In recent years, in order to reduce the size and power consumption of such conventional electric circuit switchgears, especially relays, a so-called micromachining technology, which applies a semiconductor fine processing technology, has been used. Micro-mechanical relays, in which an electric actuator and a piezoelectric actuator are formed and a movable contact is mechanically brought into contact with a fixed contact by using these as a driving source, are being studied for practical use. For example, in the paper `` Minoru Sakata, An Electrostatic Microactu
ator for Electro-Mechanical Relay, IEEEMicro Elect
Ro Mechanical Systems, 1989.2, pp. 149-151, discloses a micromachine relay using, as a driving source, an electrostatic actuator formed by forming a laminated film using gold as a contact and Cr as an adhesive layer.

However, micromachine relays using these micro-driving force sources cannot generate sufficient contact pressure to destroy the above-described defective conductor layer on the contact surface, and therefore have low contact resistance characteristics that are practical. In addition, in order to solve this problem, to increase the driving force, problems such as increased power consumption, increased driving voltage, and increased component volume occur, and thus the practicability is poor. There was a point. Also, the problem of the minimum applied load could not be solved.

As described above, by preventing the occurrence of a defective conductor layer formed on the surface of an electric contact of a device that opens and closes an electric circuit by mechanically contacting and opening the contact, the electric circuit switch device can be improved. Although miniaturization and low power consumption can be achieved, and the problem of the minimum applicable load can be solved, these problems cannot be solved by the conventional technology even if a micromachine relay is used.

The present invention has been made to solve the problem of the contact portion in the conventional device for opening and closing an electric circuit by mechanically contacting and opening the contact. By devising the material of the adhesive layer or the diffusion prevention layer or both, which is interposed between the substrate and the base, it is possible to prevent the formation of a defective conductor layer on the contact surface, achieve a low contact resistance characteristic, and thus reduce the size of the device, An object of the present invention is to provide a contact for an electric circuit switchgear and an electric circuit switchgear capable of reducing power consumption and the like.

Other objects and novel features of the present invention will be clarified in embodiments described later.

[0031]

In order to achieve the above object, a contact for an electric circuit switching device according to the present invention is characterized in that a contact layer formed on an insulating or conductive substrate is made of a noble metal, a platinum group metal or a noble metal. Or in a configuration made of an alloy of a platinum group metal and opening and closing an electric circuit depending on the presence or absence of mechanical contact,
A metal oxide layer containing a platinum group metal oxide as a main component is interposed between the base and the contact layer.

In the electric circuit switch contact, an adhesive layer and a diffusion preventing layer are interposed between the base and the contact layer in a laminated state, and one or both of the adhesive layer and the diffusion preventing layer are oxides of the platinum group metal. May be a metal oxide layer containing as a main component. Alternatively, an adhesive layer or a diffusion preventing layer is interposed between the base and the contact layer, and the adhesive layer or the diffusion preventing layer is a metal oxide layer containing an oxide of the platinum group metal as a main component. You may.

[0033] The oxide of the platinum group metal may be iridium oxide or ruthenium oxide.

In the electric circuit switchgear of the present invention, the contact layer formed on the insulating or conductive substrate is made of a noble metal or a platinum group metal or an alloy of a noble metal or a platinum group metal,
A contact that opens and closes an electric circuit depending on the presence or absence of mechanical contact,
In a configuration having at least one pair, a metal oxide layer mainly containing an oxide of a platinum group metal is interposed between the base and the contact layer in the contact.

In the electric circuit switching device, the at least one pair of contacts may be mechanically opened and closed using an electrostatic attraction as a driving force source.

[0036]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of an electric circuit switch according to the present invention;

FIG. 1 shows a first embodiment of the present invention.
1 shows a basic configuration of a contact for an electric circuit switching device. In this figure, a contact layer 3 made of a noble metal, a platinum group metal, or an alloy thereof is formed on a base 1 of a base metal or a nonmetal (which may be either conductive or insulating) via an adhesive layer 2. Here, the adhesive layer 2 is provided to increase the adhesive strength of the contact layer 3 to the substrate 1, and is formed of a metal oxide layer containing a platinum group metal oxide as a main component, as described later. ing.

The present inventor has the effect of preventing the diffusion of peripheral materials that diffuse into the contact layer 3 made of a noble metal or a platinum group metal or an alloy thereof. As the adhesive layer 2 having the function of increasing the adhesive force, various materials having sufficient conductivity and which do not diffuse into the contact layer and do not form a defective conductor layer on the surface thereof were examined.

As a result, oxides of platinum group metals such as platinum oxide, iridium oxide, palladium oxide and ruthenium oxide are converted to noble metals such as gold and platinum or platinum group metals and base metals such as copper and nickel, and silicon oxide. It has sufficient properties as an adhesive layer between non-metals such as silicon and silicon nitride, and when used as an anti-diffusion layer, very good diffusion prevention for base metal materials and non-metal materials as described above. Found to be effective.

Further, any of these platinum group metal oxides has good electrical conductivity, and can be used as a diffusion preventing layer or an adhesive layer to provide an electrical connection between a noble metal or platinum group metal contact layer and the outside. Do not interfere.

The reason why the oxides of the platinum group metals have such good adhesion and diffusion preventing effects is not sufficiently clear at present. However, the oxides of the platinum group metals are all characterized by weak bonds between oxygen and metal atoms, and have a lower decomposition temperature than ordinary base metal oxides. Therefore, at the interface between the platinum group metal oxide layer and the noble metal or platinum group metal layer used for the contact layer, the platinum group metal oxide layer is partially reduced, and the platinum group metal oxide and the noble metal or platinum group It is considered that a metal interdiffusion region is easily formed, and the adhesive strength is high.

It is considered that between the oxide layer of the platinum group metal and the base metal layer, the base metal layer is further partially oxidized to form an adhesion region between the oxides, so that a high adhesion strength can be obtained.

When the non-metal is an oxide, the non-metal is an oxide, and the oxide of the platinum group metal is an oxide. In the case of, it is considered that the adhesive strength can be obtained between the non-oxide and the platinum group metal oxide by partially oxidizing the non-oxide with the platinum group metal oxide.

The reason why the diffusion preventing effect is good is that there is almost no diffusion of a substance such as a metal in an oxide as compared with a metal such as nickel which has been conventionally used as a diffusion preventing layer. Is probably the cause.

The platinum group metal oxide layer can be easily formed by a reactive sputtering method in which platinum oxide, iridium oxide, ruthenium oxide, and palladium oxide are sputtered on respective metal targets in an oxygen atmosphere. And these oxides have good electrical conductivity and are easy to use. In particular, iridium oxide and ruthenium oxide have high conductivity and do not hinder the electrical connection between the contact layer and the outside, and the decomposition temperature is high (1,000 ° C). This is desirable because problems such as these are unlikely to occur.

The oxide of the platinum group metal may be not only an oxide of these single elements but also an oxide of an alloy. For example, a platinum group containing gold may be used for the contact layer 3 of a gold-based noble metal contact material. If an oxide layer of a metal alloy is used as the bonding layer 2, a higher bonding effect can be expected. Further, the base metal oxide may be contained in a fixed amount, preferably in a volume amount of 50% or less.

Next, the evaluation of the adhesive strength of the adhesive layer made of a platinum group metal oxide was performed as follows.

On a silicon oxide substrate as a substrate,
An iridium oxide, a palladium oxide, a ruthenium oxide, and a platinum oxide each having a thickness of 0 nm are used for an adhesive layer, and a 2 μm gold thin film is formed thereon as a contact layer.
(D3359-87) An adhesion strength test based on the cross hatch tape test was performed.

The oxides of each platinum group metal are formed by mounting each platinum group metal target on the cathode of a magnetron sputtering apparatus and performing reactive sputtering in a mixed gas of Ar and O ₂ , and subsequently, 2 μm of gold was similarly formed by a usual sputtering method using a magnetron sputtering apparatus.

For comparison, Cr and Ti were used as adhesive layers.
A sample in which each film was formed to 20 nm and a sample in which a gold film was directly formed without an adhesive layer were prepared, and an adhesion strength test was similarly performed.

Table 1 shows the results of the adhesion strength test.

Table 1 Configuration Result single layer Au single layer film OB Au / Cr 5B Au / Ti 5B Au / iridium oxide 5B Au / ruthenium oxide 5B Au / platinum oxide 4B Au / palladium oxide 4B Criteria 5B No peeling 4B Small delamination occurs along the edge of the grid of 5% or less 3B Small delamination occurs along the edge of the grid from 5 to 15% 2B Delamination occurs along the edge of the grid from 15 to 35% 1B Delamination occurs on all the grids , Large peeling from 35 to 65% 0B 65% or more lattice peeled

As is clear from Table 1, the adhesion strength was not obtained at all with a single gold film, but by using an oxide layer of a platinum group metal as an adhesive layer, the Cr layer usually used as an adhesive layer was used. Adhesive force equivalent to or close to that of a Ti or Ti layer is obtained.

Next, in order to investigate the effect of the platinum group metal oxide layer as a diffusion preventing layer, an iridium oxide and a ruthenium oxide layer were each formed on an Si substrate as a base by about 2 μm.
After forming 0 nm, a sample in which 2 μm of gold was formed as a contact layer thereon, a sample in which about 20 nm of Ni was formed as a diffusion preventing layer for comparison, and an adhesive layer Cr and a Ti film were formed in 20 nm each in place of the diffusion preventing layer Each sample was prepared and a sample in which 2 μm of gold was directly formed without a diffusion preventing layer was prepared. Each of the samples was heat-treated at 600 ° C. in air, and the gold surface was evaluated by Auger electron spectroscopy. In addition, as a method of forming each layer, a sputtering method was used as in Table 1 above.

Table 2 shows the results of the surface composition analysis.

Table 2 Configuration Surface composition analysis results Au / Si substrate Gold silicide and SiO ₂ layer Au / Ni / Si substrate Gold silicide and SiO ₂ , Ni oxide layer Au / iridium oxide / Si substrate Clean gold surface Au / ruthenium oxide Material / Si substrate Clean gold surface Au / Cr / silicon oxide substrate Cr oxide layer Au / Ti / silicon oxide substrate Ti oxide layer

As is clear from Table 2, the conventional diffusion preventing layer made of Ni or the like or the adhesive layer made of Cr, Ti or the like cannot provide a sufficient diffusion preventing effect, and in addition, itself cannot be made of gold. It deposits on the surface and forms a defective conductor layer. On the other hand, the adhesive layer made of iridium oxide or ruthenium oxide, which is an oxide of a platinum group metal, which is described in this embodiment, has a good effect as a diffusion prevention layer, and according to the present embodiment. In the contact configuration, it is possible to completely prevent diffusion of the base material and base metal material, which could not be prevented by the conventional diffusion prevention layer, and by using this for the contact of an electric circuit switch, it is formed on the contact surface. It is possible to completely prevent the generation of a defective conductor layer.

In the examples shown in Tables 1 and 2, silicon and silicon oxide are used as the substrates. However, the substrates are not limited to these, and base metals such as copper, phosphor bronze, and stainless steel may be used. Also in this case, a bonding layer of a metal oxide containing a platinum group metal oxide as a main component can provide the same bonding effect and diffusion preventing effect. Further, when a platinum group metal such as platinum, iridium, palladium or the like or an alloy thereof is used in addition to a noble metal such as gold as the contact layer, completely the same adhesive effect and diffusion preventing effect can be obtained.

According to the contact for an electric circuit switching device shown in the first embodiment, the following effects can be obtained.

(1) An adhesive layer 2 formed of a metal oxide layer containing an oxide of a platinum group metal as a main component is bonded to a base 1 and a contact layer 3 made of a noble metal or a platinum group metal or an alloy thereof.
The contact surface that maintains a completely clean metal surface does not occur because a defective conductor layer on the contact surface formed by diffusion from the contact peripheral material, which was inevitable in the past, does not occur. Can be configured.

(2) For this reason, it is necessary to mechanically and electrically destroy the defective conductor layer on the contact surface by applying a physically strong pressure between the contacts and flowing a larger contact current as in the prior art. Absent.

(3) It is not necessary to use an actuator having a large generating force, which is necessary for obtaining a large contact pressure, and it is easy to reduce the size and power consumption of the electric circuit switchgear.

(4) The limitation on the minimum applicable load, which narrows the range of use of the conventional electric circuit switching device, is eliminated, and the switching of minute signals can be facilitated. In particular, it solves the problem of micromachine relays that use a small driving force such as electrostatic actuators, which previously lacked practicality because a large contact pressure could not be obtained and a low contact resistance could not be obtained. It can be improved.

In the first embodiment, the adhesive layer 2 between the base 1 and the contact layer 3 utilizes the adhesive action and diffusion preventing action of a metal oxide layer containing a platinum group metal oxide as a main component. However, the structure may be divided into two layers, that is, an adhesive layer and a diffusion prevention layer. This case is shown in FIG. 2 as a second embodiment of the present invention.

In the second embodiment shown in FIG. 2, reference numeral 1 denotes a substrate, on which an adhesive layer 4 and a diffusion preventing layer 5 are sequentially laminated, and a contact layer 3 is formed thereon. Here, the base 1 may be a base metal or a nonmetal (either conductive or insulating), and the adhesive layer 4 may be a general Cr, Ti, or the like.
The diffusion preventing layer 5 is a metal oxide containing a platinum group metal oxide as a main component, and the contact layer 3 is made of a noble metal, a platinum group metal, or an alloy thereof as in the first embodiment.

In this case, an adhesive layer 4 is formed for the purpose of further improving the adhesiveness to the substrate 1, and the diffusion preventing layer 5 made of a metal oxide mainly composed of an oxide of a platinum group metal is mainly used for the purpose of preventing diffusion. Is provided.

Here, in order to examine the effect of the platinum group metal oxide layer as the diffusion preventing layer 5 when the base metal adhesive layer was used, a Cr and Ti adhesive layer was formed on a silicon oxide substrate to a thickness of about 20 nm. Thereafter, a sample in which an iridium oxide and ruthenium oxide layer is formed to a thickness of about 20 nm as a diffusion prevention layer 5 and a sample in which gold is formed to be 2 μm as a contact layer 3 and a sample in which about 20 nm of Ni is formed as a diffusion prevention layer for comparison A sample in which 2 μm of direct gold without a diffusion preventing layer was formed on the adhesive layer was prepared, each was heat-treated at 600 ° C. in air, and the gold surface was evaluated by Auger electron spectroscopy. In addition, as a method of forming each layer, a sputtering method was used as in Table 1 above.

Table 3 shows the results of the surface composition analysis.

Table 3 Configuration Surface composition analysis results Au / Cr / silicon oxide substrate Cr oxide layer Au / Ti / silicon oxide substrate Ti oxide layer Au / Ni / Cr / silicon oxide substrate Cr oxide layer Au / iridium oxide / Cr / Silicon oxide substrate Clean gold surface Au / iridium oxide / Ti / silicon oxide substrate Clean gold surface Au / ruthenium oxide / Cr / silicon oxide substrate Clean gold surface Au / ruthenium oxide / Ti / silicon oxide substrate Clean gold surface

As is clear from Table 3, the diffusion preventing layer made of Ni or the like or the adhesive layer made of Cr, Ti, etc., which has been conventionally used, cannot provide a sufficient diffusion preventing effect and is itself made of gold. It deposits on the surface and forms a defective conductor layer. On the other hand, in the contact structure using the diffusion prevention layer made of iridium oxide or ruthenium oxide, which is an oxide of a platinum group metal, shown in the present embodiment, the substrate which could not be blocked by the conventional diffusion prevention layer It is possible to completely prevent the diffusion of the base metal material of the material and the adhesive layer, and by using this for the contacts of electric circuit switchgear, it is possible to completely prevent the occurrence of defective conductor layers formed on the contact surfaces. It is possible.

According to the second embodiment, two layers of the adhesive layer 4 and the diffusion prevention layer 5 are interposed between the base 1 and the contact layer 3, and the adhesive It is possible to select a material having a high effect of improving adhesiveness, and
This has the advantage that materials having a high diffusion prevention effect can be individually selected. Other functions and effects are the same as those of the first embodiment.

Although the example of Table 3 shows an example of silicon oxide as the substrate, the substrate is not limited to this, and a base metal substrate such as copper, phosphor bronze, or stainless steel may be used. Also, a diffusion preventing layer of a metal oxide containing a platinum group metal oxide as a main component can provide the same diffusion preventing effect. Further, when a platinum group metal such as platinum, iridium, palladium or the like or an alloy thereof is used in addition to a noble metal such as gold as the contact layer, completely the same diffusion preventing effect and adhesive effect can be obtained. Further, a conventional general material such as Cr and Ti can be used for the adhesive layer 4, but the adhesive layer 4 is also a metal oxide mainly composed of an oxide of a platinum group metal different from the diffusion prevention layer 5. It is also possible to form them in layers.

FIGS. 3 and 4 show a third embodiment of the present invention, in which an electrostatic actuator is used as a drive source as an example of an electric circuit switch having at least one pair of contacts for the electric circuit switch. The case where a micro relay (electrostatic relay) is configured is shown.

In these figures, the micro relay is
An insulating substrate, an anchor structure 12 erected and fixed on the substrate 10, and a torsion-like torsion elastic portion 13 supported by the anchor structure 12 with a gap from the substrate 10.
And an electrostatic relay structure 20 rotatable by elastic support by the torsion elastic portion 13. That is, the electrostatic relay structure 20 is held with a gap from the substrate 10 via the anchor structure 12 and the torsion elastic portion 13,
In addition, the substrate 10 can be rotated with respect to the substrate 10 by the torsional elasticity of the torsionally elastic torsion 13. The electrostatic relay structure 20 includes a doubly supported beam connecting portion 21, an electrostatic actuator movable electrode support portion 22, and a movable contact support portion 23.

A movable contact 24 is formed on the movable contact supporting portion 23 of the electrostatic relay structure 20 on the side facing the substrate, and an electrostatic actuator movable electrode 25 is disposed on the surface of the electrostatic actuator movable electrode supporting portion 22. You. A fixed contact 14 and an electrostatic actuator fixed electrode 15 are formed and arranged on the substrate 10 at a position facing these. The fixed electrode 15 fixed on the insulating substrate 10 and the movable electrode 25 fixed on the movable electrode support 22 are parts constituting an electrostatic actuator that generates an electrostatic attraction by a voltage applied between them. The fixed electrode 15 and the movable electrode 25 of the electrostatic actuator are connected to an external power supply by wiring (not shown).

The fixed contact 14 and the movable contact 24 have a contact structure as shown in the second embodiment of the present invention. That is, the fixed contact 14 is made of Au having a thickness of 1 μm.
A contact layer 30 made of iridium oxide and a bonding layer 32 made of 10 nm Cr
Are laminated on a substrate 10 as a base through the substrate. The movable contact 24 includes a contact layer 40 made of 500 nm of Au, a diffusion prevention layer 41 made of an iridium oxide layer of about 20 nm, an adhesive layer 42 of Cr 10 nm, and an adhesive layer 42 of about 20 nm.
Is formed on the lower surface of the movable contact support portion 23 on the side of the electrostatic relay structure via the SiN reaction prevention layer 43 of FIG. In addition, since the fixed electrode 15 is also manufactured at the same time as the fixed contact 14, the fixed electrode 15 has the same laminated structure, and the same layer as the fixed contact 14 has the same reference numeral.

Next, a method of manufacturing the micro relay shown in this embodiment will be described.

First, an approximately 1 μm thick Si
Using a single-crystal Si substrate on which an O ₂ insulating layer is formed as a substrate 10, a contact layer 30 made of a 1 μm-thick Au layer is formed by sputtering into a diffusion preventing layer 31 made of iridium oxide 20 nm and an adhesion layer 32 made of Cr 10 nm. Was formed over the entire surface of the substrate. Next, the electrostatic actuator fixed electrode 15 and the fixed contact 14 of the relay were patterned using photoetching.

Next, an SiO ₂ film serving as a sacrificial layer is formed on the entire surface of the substrate at a temperature of about 400 ° C. by a CVD method at a temperature of about 400 ° C.
μm was deposited.

Then, the portion of the SiO ₂ film which will become the movable contact 24 on the sacrificial layer is formed by photo-etching to a thickness of about 500.
After etching, an Au film of about 500 nm is formed on the entire surface of the substrate as a contact layer 40 by a sputtering method, and an iridium oxide layer of about 20 nm and an adhesion layer 42 of about 10 nm of Cr and a S layer of about 20 nm are formed as a diffusion prevention layer 41.
An iN reaction prevention layer 43 was formed.

The Au / iridium oxide /
The actuator movable contact 24 was formed by patterning the Cr / SiN layer into the shape of the movable contact 24 by photoetching. Thereafter, the SiO ₂ film of the sacrificial layer corresponding to the anchor structure 12 supporting the electrostatic relay structure 20 is selectively removed by photoetching.

Next, a Si film is formed to a thickness of about 6 μm on the entire surface of the substrate by using a sputtering method.
Heat treatment was performed at 00 ° C. This Si film was patterned into the shape of the electrostatic relay structure 20 described below by the RIE method.

The torsionally elastic portion 13 having a cantilever shape has a length a of about 100 μm and a width of about 10 μm from the anchor structure 12.
The length b of the electrostatic relay structure 20 is about 100 μm.
Connection part 21, width c is about 200 μm, and length d is about 200
It is composed of an electrostatic actuator movable electrode support part 22 of μm and a movable contact support part 23 having a length e of about 50 μm.

After forming the electrostatic relay structure 20, an Au film 51 of about 100 nm is formed on the structure as a movable electrode 25 via an SiN insulating layer 50 of about 10 nm. The shape was patterned by photoetching.

Finally, the SiO ₂ sacrificial layer was etched with hydrofluoric acid, the electrostatic relay structure 20 was released, and predetermined wiring was performed to complete a micro relay.

The present microrelay is an electrostatic relay, and the entire actuator structure is a movable structure that can be rotated by the torsional elasticity of the torsionally elastic torsion part 13, and the movable electrode 25 and the fixed electrode of the electrostatic actuator are used. 1
By applying a voltage between the electrodes 5, an electrostatic attractive force acts between the actuator electrodes, and the movable contact 24 and the fixed contact 14 are brought into mechanical contact with each other to close the electric circuit.

In this embodiment, by applying an operating voltage of about 20 V or less between the electrostatic actuator electrodes,
The contact was closed, and the contact resistance at this time was about 0.5Ω.
Further, the contact resistance did not change at all even after the reliability test at 100 ° C. for 1000 hours.

As a comparative example, an electrostatic relay having the same structure but omitting the iridium oxide diffusion preventing layers 31 and 41 was prepared.
As a result of the evaluation, the operating voltage was slightly lower than about 20 V, but the contact resistance showed an extremely high value of 100 kΩ to 100 MΩ or more. Furthermore, as a result of evaluating the fixed contact surface of the electrostatic relay formed in this embodiment and the comparative example by Auger electron spectroscopy, the contact surface in this embodiment was a clean gold surface, but almost completely in the comparative example. It was found that it was covered by the Cr oxide layer.

As is clear from the above, the third aspect of the present invention
The micro relay shown in the embodiment of the present invention realizes a low contact resistance, which was impossible in the past, and has high practicality. High reliability can be easily achieved.

In the third embodiment, the contact structure is such that the adhesive layer and the diffusion preventing layer are interposed between the substrate and the contact layer. However, as shown in the first embodiment, the substrate and the contact layer And an adhesive layer of a metal oxide containing a platinum group metal oxide as a main component may be interposed therebetween.

In this embodiment, an example in which the electrostatic relay structure is formed by using the thin film forming technique has been described. However, the configuration method of the electrostatic relay as the electric circuit switching device of the present invention is not limited to this. Instead of, for example, a monocrystalline Si substrate as an electrostatic relay structure, a diffusion prevention of a metal oxide containing a platinum group metal oxide as a main component as in the present embodiment, and a movable contact using an adhesive layer. After forming a movable electrode and forming it into a predetermined structure using a technique such as anisotropic etching, the diffusion prevention of a metal oxide mainly containing an oxide of a platinum group metal,
It may be attached via a spacer to an insulating substrate on which a fixed contact and a fixed electrode using an adhesive layer are formed.

Even in such a case, it is possible to easily obtain a highly reliable electrostatic relay with low contact resistance as compared with the conventional structure.

It is also possible to use a thin metal plate whose surface is insulated for the electrostatic relay structure. An electrostatic relay formed by such a method is applicable to an application in which a larger contact current flows than an electrostatic relay using a thin film forming technique.

Although the iridium oxide layer is used as a diffusion preventing layer here, the same effect can be obtained by using a ruthenium oxide layer, and the contact layer is made of another platinum group metal oxide layer. Even when using a platinum oxide layer or a palladium oxide layer, if the manufacturing process is set within the range of the respective decomposition temperatures or less, the same diffusion prevention and adhesion effects can be obtained, and low contact resistance characteristics can be obtained.

In the present embodiment, an electrostatic relay using an electrostatic actuator has been described as an example of a driving force source for a movable contact. However, the contact of the present invention and a driving source for an electric circuit opening / closing device using the same are used as a driving source. However, the present invention is not limited to electrostatic actuators, and it is possible to use a small driving force, such as a micro magnetic drive circuit or a piezoelectric bimorph actuator, as a drive source for a movable electrode. As a result of reducing power consumption, the present invention can be applied to all small electric circuit switchgears in which sufficient contact pressure is difficult to generate. Further, if the contact configuration of the present invention is used in a conventional electric circuit switchgear, the conventional problem of minimum applied load can be easily solved.

Although the embodiments of the present invention have been described above, it is obvious to those skilled in the art that the present invention is not limited to the embodiments and various modifications and changes can be made within the scope of the claims. There will be.

[0097]

As described above, according to the contact for an electric circuit switching device according to the present invention, the bonding between the base and the contact layer is made of a metal oxide mainly composed of a platinum group metal oxide. By interposing a layer or a diffusion prevention layer, it is possible to completely prevent the base material or the base metal material of the adhesive layer from being diffused, which could not be prevented by the conventional diffusion prevention layer, and to form a defective conductor formed on the contact surface. It is possible to completely prevent the formation of layers. Therefore, it is not necessary to destroy the defective conductor layer on the contact surface by mechanical pressure or excessive contact current when the contacts are brought into contact as in the prior art. For this reason, even if the force generated by the actuator that mechanically drives the contacts is reduced, the problem of contact resistance failure does not occur, and an electric circuit switchgear without limitation on the minimum applicable load can be realized.

In particular, the configuration of the electric circuit switchgear using the contacts for the electric circuit switchgear according to the present invention has not been able to obtain a large contact pressure and a low contact resistance conventionally, so that practicality has been reduced. It is possible to solve the problem of the micromachine relay using the minute driving force of the lacking electrostatic actuator or the like, and to significantly improve the practicality. That is, low contact resistance, miniaturization, low power consumption, and high reliability, which were impossible in the past, can be easily achieved.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing an example of a contact for an electric circuit switching device according to a first embodiment of the present invention.

FIG. 2 is a sectional view showing another example of the contact for the electric circuit switchgear according to the second embodiment of the present invention.

FIG. 3 is a front sectional view showing a micro relay as an electric circuit switching device according to a third embodiment of the present invention.

FIG. 4 is a plan view of the same.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Base | substrate 2,4,32,42 Adhesive layer 3,30,40 Contact layer 5,31,41 Diffusion prevention layer 10 Substrate 12 Anchor structure 13 Double-ended beam-shaped torsion elastic part 14 Fixed contact 15 Static actuator fixed electrode DESCRIPTION OF SYMBOLS 20 Electrostatic relay structure 21 Doubly supported beam connection part 22 Electrostatic actuator movable electrode support part 23 Movable contact support part 24 Movable contact 25 Electrostatic actuator movable electrode

Claims (6)

[Claims] A contact layer formed on an insulating or conductive substrate is made of a noble metal or a platinum group metal or an alloy of a noble metal or a platinum group metal, and is used to open and close an electric circuit depending on the presence or absence of mechanical contact. A contact for an electric circuit switch, wherein a metal oxide layer mainly composed of a platinum group metal oxide is interposed between the base and the contact layer. 2. An adhesive layer and a diffusion preventing layer are interposed between the substrate and the contact layer in a laminated state, and one or both of the adhesive layer and the diffusion preventing layer are metal oxides mainly composed of the platinum group metal oxide. The contact for an electric circuit switchgear according to claim 1, which is a material layer. 3. An adhesive layer or a diffusion preventing layer is interposed between the base and the contact layer, and the adhesive layer or the diffusion preventing layer is a metal oxide mainly composed of an oxide of the platinum group metal. The contact for an electric circuit switchgear according to claim 1, which is a layer. 4. The contact according to claim 1, wherein the platinum group metal oxide is iridium oxide or ruthenium oxide. 5. A contact layer formed on an insulating or conductive substrate is made of a noble metal or a platinum group metal or an alloy of a noble metal or a platinum group metal, and opens and closes an electric circuit depending on the presence or absence of mechanical contact. An electric circuit switchgear having at least one pair of contacts, wherein a metal oxide layer containing a platinum group metal oxide as a main component is interposed between the base and the contact layer in the contacts. Electrical circuit switchgear. 6. The electric circuit switching device according to claim 5, wherein the at least one pair of contacts is mechanically opened and closed by using electrostatic attraction as a driving force source.