JP2003242850A - Contact for electrical switch and its manufacturing method as well as electrical switch - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve the problems on a conventional contact for an electrical switch, which has a roughness on the surface for reducing a contact area to prevent adhesion, that a contact material has low hardness and a protruded portion has a large minimum diameter, resulting in a low adhesion preventing effect. <P>SOLUTION: A adhesive metal layer 61, a contact metal layer 62 and a high-melting-point metal layer 63 are laminated in sequence on the upper face of a glass substrate 3 with vapor deposition or spattering. Then, the high- melting-point metal layer 63 is removed therefrom with etching while leaving part thereof instead of complete removal, to form such a contact surface that there is a roughness even on the surface of the contact metal layer 62 and the part of the high-melting-point metal layer 63 exists near the tops of protruded portions. The minimum diameter of the protruded portion on the surface of a contact 6 formed in this way is 1 μm or so, producing a high adhesion preventing effect. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a contact for an electric switch such as an electric switch and a relay, a method for manufacturing the same, and an electric switch.

[0002]

2. Description of the Related Art As a conventional contact for an electric switch, for example, there is a contact structure for a micro relay disclosed in Japanese Patent Laid-Open No. 2000-173375. This is because when a relay contact is formed by a vapor deposition method or a sputtering method, its surface becomes a mirror surface, and when the contact is closed, the surfaces of the contact adhere to each other due to adhesion and it becomes difficult to separate. In order to prevent this, the feature is that the surface of the relay contact is made uneven.

In Japanese Patent Laid-Open No. 2000-173375, after forming a contact by a vapor deposition method or a sputtering method, a checkered resist mask is formed by a photolithography method, and a concave portion of the contact is removed by an etching method to form unevenness. Roughness is formed by a plasma bombardment process or an ion bombardment process. The unevenness prevents adhesion or the like that occurs when the contacts are closed, and the contacts can be smoothly opened.

[0004]

However, the material for these contacts is a material such as Au having a low hardness and a low melting point in view of contact resistance and conductivity (generally, a material having a low hardness is a melting point). The material has a low melting point and a high hardness, and is often formed with a high melting point). It tends to spread and stick.

As a method for forming irregularities on the contact surface, for example, when irregularities are formed by a photolithography method and an etching method, when a general-purpose photolithography method is used, only a coarse checkered resist mask is formed. This is not possible, and the minimum diameter of the protrusion on the contact surface is at most 10 μm.
It can only be processed to a certain degree. If the minimum diameter of the convex portion is about 10 μm, the effect of preventing sticking cannot be sufficiently obtained. In order to obtain a sufficient effect of preventing sticking, it is necessary to form a minimum convex portion diameter of about 1 μm. Furthermore, since the same metal is patterned twice to form the concavities and convexities, the number of steps is increased, leading to an increase in cost. There is also a problem that side etching is likely to occur and the yield is reduced.

Therefore, in order to finely process the diameter of a projection that is small enough to obtain an anti-adhesion effect by using the photolithography method, a high resolution photolithography technique used for LSI or the like is required, and the number of steps is further increased. The yield will be further reduced.

Although it is possible to form a minimum convex portion diameter of about 1 μm by using a plasma bombardment process or an ion bombardment process, members other than contacts are damaged and contact materials scatter around due to the bombardment process. However, the yield is lowered and the characteristics are deteriorated. Therefore, an object of the present invention is to provide a contact for an electric switch, which has a stable contact resistance and a high adhesion preventing effect without increasing man-hours, reducing yield, and deteriorating characteristics.

[0008]

As a means for solving the above problems, the present invention provides, in the invention of claim 1, an electric switch contact used for an electric switch for conducting and interrupting an electric current, It is characterized in that minute irregularities are formed on the surface of the contact, and a material having a higher melting point than the material of the contact is dispersed on the surface of the contact.

According to a second aspect of the invention, in the contact for an electric switch according to the first aspect, the high melting point material is present in the vicinity of the apex of the convex portion of the unevenness of the contact.

According to a third aspect of the present invention, in the electric switch contact according to the first or second aspect, the contact material is Au.

According to a fourth aspect of the invention, in the electrical switch contact according to the first or second aspect, the high melting point material is any one of W, Pt, Pd, Ru and Rh. There is.

According to a fifth aspect of the present invention, in the method of manufacturing a contact for an electric switch, a material having a melting point higher than that of the contact material is laminated by an evaporation method or a sputtering method so as to cover the surface of the contact material, and then the etching method is used. It is characterized in that the high melting point material is removed so as to leave a part thereof to form a contact for an electric switch.

According to a sixth aspect of the present invention, in an electric switch, the electric switch contact according to any one of the first to fourth aspects is used for at least one of the opening and closing contacts.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the accompanying drawings. FIG. 1 shows a schematic view of an electrostatic micro relay as an embodiment of an electric switch using the electric switch contact according to the present invention as a fixed contact. In this electrostatic micro relay 1, a movable substrate 10 is integrally formed on an upper surface of a fixed substrate 2, and a glass cap 20 is formed on the movable substrate 10.
It is configured to be covered with.

The fixed substrate 2 is formed by forming a fixed electrode 4 and two signal lines 5 and 5 on the upper surface of a glass substrate 3, respectively. The surface of the fixed electrode 4 is covered with an insulating film 7,
The ends form the connection pads 4a, 4b, 4c, 4d. The signal lines 5 and 5 are formed on the same straight line so that their ends have a predetermined interval, and the ends of the signal lines 5 and 5 closer to each other are fixed contacts 6 and 6.

The fixed electrodes 5 are formed on both sides of the signal lines 5 and 5 with the same distance, and the GND of the signal lines 5 and 5 is also formed.
It also serves as an electrode to form a coplanar structure.

The movable substrate 10 is formed of a substantially rectangular plate-shaped silicon substrate, has a support portion 11 at a position point-symmetric with respect to its center, and extends from the support portion 11 along the outer edge. The movable electrode 14 via the two first elastic support portions 13, 13 formed by the slits 12, 12 of the book.
Is elastically supported, and the movable contact portion 16 is elastically supported in the central portion thereof via the two second elastic support portions 15, 15.

The supporting portions 11 are respectively erected on the fixed substrate 2 so that the movable substrate 10 faces the fixed substrate 2, and as a result, the movable electrode 14 faces the fixed electrode 4 at a predetermined interval. . The support portion 11 is electrically connected to the connection pad 8b via the wiring 8a provided on the upper surface of the fixed substrate 2. Further, the movable electrode 14 has at least a portion facing the signal lines 5 and 5 removed. A movable contact 17 is formed on the lower surface of the movable contact portion 16 at a position facing the fixed contacts 6, 6 with an insulating film (not shown) interposed therebetween.

The movable electrode 14 is attracted to the fixed electrode 4 by the electrostatic attraction generated when a voltage is applied between the movable electrode 14 and the fixed electrode 4, so that the movable contact 17 supported by the movable electrode 14 is fixed. The contact points 6 and 6 are closed to electrically connect the signal lines 5 and 5.

Next, the structure of the fixed contact 6 (hereinafter referred to as contact 6) of the electrostatic micro-relay having the above-mentioned structure is shown in FIG.
Will be explained. The contact 6 is the contact according to the present invention as described above. In order to clarify the characteristics of the invention in FIG. 2, the actual correlation between the thickness of each layer and the unevenness is not necessarily accurate.

The contact 6 is formed on the glass substrate 3 by the adhesion metal layer 6
1. A contact metal layer 62 made of a contact material and a refractory metal layer 63 made of a refractory material are laminated and then removed by etching so as to partially leave the refractory metal layer 63. As the adhesion metal layer 61, for example, a Cr layer having a thickness of about 0.05 μm is laminated. As the contact metal layer 62, an Au layer having a thickness of, for example, about 2 μm is laminated on the contact metal layer 61. Asperities 64 are formed on the surface of the contact metal layer 62, and R having a melting point higher than that of Au is formed in the vicinity of the peaks of the protrusions.
A part of the refractory metal layer 63 made of u is present.

Since Ru has a higher melting point and a higher hardness than Au, even if it is closed with the movable contact 28 whose surface material is Au, no sticking occurs.

Note that Ru in a portion corresponding to the signal line 5 is not removed, and has a three-layer structure of Ru / Au / Cr.

Next, a method of manufacturing the contact 6 will be described. FIG. 3 shows a cross-sectional view and a perspective view of a flow of a method of manufacturing the fixed substrate 2 including the contacts 6. The adhesion metal layer 6 is formed on the upper surface of the glass substrate 3 by vapor deposition or sputtering.
A Cr layer having a thickness of, for example, about 0.05 μm is laminated as 1, and an Au layer having a thickness of, for example, about 2 μm is laminated as the contact metal layer 62. In this state, no unevenness is formed on the surface of the Au layer.

Further, a high melting point metal layer 63, for example, a Ru layer having a thickness of about 0.4 μm is laminated in this order (FIG. 3).
(A)). At this time, in order to prevent the adhesion metal layer 61 from diffusing into the contact metal layer 62, a barrier layer (not shown) may be provided between the adhesion metal layer 61 and the contact metal layer 62.
Although not shown, irregularities are formed on the surface of the refractory metal layer at this time. It is presumed that this is due to the melting point of the high melting point metal and the energy at the time of lamination.

Next, the refractory metal layer 63 is patterned into a desired shape by using a photography method or an etching method (FIG. 3B). The etching for the contact 6 is disclosed in JP
Instead of using a checkered resist mask like 000-173375 to partially etch, the entire contact is etched. Then, when the refractory metal layer 63 is not completely removed but is partially removed, the contact metal layer 62 is removed.
Is also uneven, and a contact surface is formed such that a part of the refractory metal layer 63 is present near the apex of the projection. This state is the surface state of the contact 6. The minimum diameter of the convex portion on the surface of the contact 6 thus formed is about 1 μm, and the effect of preventing adhesion is high.

Next, the contact metal layer 62 is similarly patterned by using a photolithography method or an etching method to have a desired shape (FIG. 3C), and then the adhesion metal layer 61 is similarly subjected to the photolithography method or the etching method. Patterning into a desired shape by using the method (FIG. 3D). afterwards,
An insulating layer 65 is formed at a necessary portion by using a sputtering method, a photolithography method, and an etching method (FIG. 3).
(E)). At this time, a part of the adhesion metal layer 61 is partially fixed to the fixed electrode 4.
Then, the contact metal layer 61 and a part of the contact metal layer 62 become the signal lines 5 and 5. The refractory metal layer 63 has a function as a cover layer to reduce damage to the contact metal that occurs during the process.

[0028]

In the electric switch contacts according to the first to fourth aspects of the present invention, since minute irregularities are formed on the surface of the contact, when the other contact is closed to conduct current, The contact area between the contacts is small, and because the material with a higher melting point, that is, a higher hardness than the material of this contact is dispersed on the contact surface, the contact surface is crushed by the contact force and the contact area becomes large, making it easy to stick. Can be prevented. In order to enhance the effect, it is desirable that the high-melting-point material be present near the apexes of the convex portions of the irregularities. The high melting point materials are W, Pt, Pd, Ru,
It is desirable to be any one of Rh. Further, the material of the contact metal layer is preferably Au in terms of contact reliability.

In the method of manufacturing a contact for an electric switch according to the invention of claim 5, a high melting point material is laminated by an evaporation method or a sputtering method so as to cover the surface of the lower layer material, and then the high melting point material is etched by an etching method. By forming a contact for an electric switch by removing it so as to leave a part thereof, the minimum diameter of the convex and concave convex portions is formed to be about 1 μm, and a contact effective for preventing adhesion can be manufactured.

[Brief description of drawings]

FIG. 1 is a diagram showing a configuration of an electrostatic micro relay according to the present invention.

FIG. 2 is a schematic view of a contact for an electric switch according to the present invention.

FIG. 3 is a diagram showing a flow of manufacturing a contact for an electric switch according to the present invention.

[Explanation of symbols]

1 Electrostatic micro relay 2 Fixed substrate 3 glass substrates 4 fixed electrode 4a-4d connection pad 5 signal lines 6 fixed contacts 7 Insulating film 8a wiring 8b connection pad 10 movable substrate 11 Support 12 slits 13 First elastic support 14 movable electrode 15 Second elastic support portion 16 Moving contact part 17 Moving contact 20 glass caps 61 Adhesion metal layer 62 contact metal layer 63 Refractory metal layer 64 uneven part

Claims (6)

[Claims] 1. A contact for an electric switch used in an electric switch for conducting and interrupting an electric current, wherein minute irregularities are formed on the surface of the contact, and the surface of the contact has a melting point higher than that of the material of the contact. The contacts for electric switches are characterized by the fact that the material is dispersed. 2. The high-melting-point material is present in the vicinity of the apex of the convex portion of the unevenness of the contact.
Contact for electric switch described in. 3. The contact for an electric switch according to claim 1, wherein the contact material is Au. 4. The high melting point material is W, Pt, Pd, R
It is either one of u and Rh, The contact for electric switches of Claim 1 or 2 characterized by the above-mentioned. 5. An electric switch contact for use in an electric switch for conducting and interrupting an electric current is formed by laminating a material having a higher melting point than the contact material by vapor deposition or sputtering so as to cover the surface of the contact material, and then etching. A method of manufacturing a contact for an electric switch, which is formed by removing a part of the high melting point material by a method. 6. An electric switch using the contact for electric switch according to claim 1 as at least one of the contacts for opening and closing.