JP2012038661A - Mems switch and method of manufacturing mems switch - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a structure of an MEMS switch capable of reducing loss in a switch, and a method of manufacturing the same.SOLUTION: A contact metal thin film 21 is disposed only in a portion opposed to a second wiring 3. Hence, a distance that a high frequency signal passes through the contact metal thin film 21 is decreased, thereby reducing loss in a MEMS switch. That is, owing to so-called skin effect, a high frequency signal having a higher frequency flows on a surface of a conductor more easily, and loss in the switch increases when the surface is covered with a material of high resistivity compared to when not covered therewith. However, because the contact metal thin film 21 is disposed only in the portion opposed to the second wiring 3 as described above, the distance that the high frequency signal passes through the contact metal thin film 21 is decreased, thereby preventing an increase in loss in the switch.

Description

  The present invention relates to a MEMS switch that controls passage and blocking of an electrical signal by MEMS (Micro Electro Mechanical Systems) technology, and a method of manufacturing the MEMS switch.

  In recent years, small terminal devices capable of wireless communication, such as mobile phones, PDAs (Personal Digital Assistants), and PCs (Personal Computers), have various types including high-frequency regions of several GHz or more as broadband and globalization progress. Therefore, it is required to support a plurality of communication systems using various frequency bands. In general, in a small terminal device, correspondence to a plurality of communication methods is realized by switching an antenna or a transmission / reception circuit used for communication by a high-frequency switch. Considering the characteristics of a small terminal device, it is desired that the high frequency switch has low insertion loss and high isolation, is small and low in profile, can be driven at a low voltage, and has low power consumption. In consideration of the case where it is applied to a transmission unit of a high-frequency circuit such as a switch for switching a power amplifier, for example, the high-frequency switch is desired to be able to switch the passage and blocking of a high-power signal of several watts.

  Therefore, MEMS switches are attracting attention as high-frequency switches suitable for switching such high-frequency signals of several GHz band or higher. The MEMS switch has a mechanically movable contact, and can be expected to have low insertion loss and high isolation in a wide frequency band including a high frequency region (for example, see Non-Patent Document 1). . In particular, a MEMS switch driven by electrostatic attraction has a feature that power consumption is small.

  In such a MEMS switch, gold is used as a contact material in order to further reduce the insertion loss. However, since gold is a material that is easily fixed to each other, if gold is used as a contact material, it is fixed when the contact comes into contact. When the force to be fixed (hereinafter referred to as a fixing force) exceeds the restoring force for separating the contact by the MEMS switch, the contact cannot be separated while being in contact. When such a state occurs, the MEMS switch continues to be in a signal passing state and cannot interrupt the signal. Such a failure is likely to occur particularly when a large amount of power passes through the contact point or during repeated operations. In order to be able to cut off the signal even in such a case, it is necessary that the restoring force by the MEMS switch exceeds the fixing force of gold. The necessary voltage will also increase. Thus, there is a trade-off relationship between high power durability, high repetitive durability, and low voltage driving.

  In order to solve such a problem, by using Ru (ruthenium), Rh (rhodium), or AuCo (gold cobalt) as a contact material, a technique for reducing the adhesion of the contact to such an extent that it does not contribute to operating characteristics. Has been proposed (see, for example, Patent Document 1). Also, one of the contact materials is made of gold, and the other is selected from one metal selected from Ir, Rh, Os, Ru, Re, Te, or TiN, ZrN, HfN, VN. A technique has also been proposed in which the contact resistance is kept low and the life is extended by using a material containing one metal (see, for example, Patent Document 2).

JP 2001-266727 A JP 2008-053077 A

G.M.Rebeiz and J.B.Muldavin, “RF MEMS switches and switch circuits”, IEEE Microwave Magazine, Vol.2, No.4, pp.59-71, Dec.2001.

  In the conventional MEMS switch as described above, the contact material is provided over almost the entire surface on which the material is provided. For example, Patent Document 1 includes a fixed metal provided on a substrate and a lower electrode provided on a lower surface of a beam provided substantially parallel to the substrate above the substrate, and the beam moves downward. Accordingly, a MEMS switch in which a fixed metal and a lower electrode are in contact with each other is disclosed. In this MEMS switch, the lower electrode made of the contact material as described above is formed over the entire lower surface of the beam. Further, Patent Document 2 includes a signal line provided on a substrate, and a contact electrode provided on a lower surface of an insulating member provided above a portion where the signal line is separated. There is disclosed a micromachine switch that conducts a signal line by moving downward and coming into contact with both edges of a separated part of the signal line. In this micromachine switch, the contact metal made of the contact material as described above is formed over the entire lower surface of the insulating member.

  When a high-frequency signal flows through such a MEMS switch, the signal flows on the surface of a member constituting the MEMS switch due to a so-called skin effect. For this reason, when a contact material with a high resistivity is provided over almost the entire surface on which the material is provided, as in the conventional MEMS switch described above, a high-frequency signal mainly passes through the contact material with a high resistivity. As a result, the loss of the signal increases.

  Therefore, an object of the present invention is to provide a structure of a MEMS switch that can reduce a loss in the switch and a manufacturing method thereof.

  In order to solve the above-described problems, a MEMS switch according to the present invention includes a substrate having at least an upper surface made of an insulating material, a first wiring provided at least partially on the upper surface of the substrate, and the first switch. A second wiring that is separated from the wiring and at least part of which is provided on the upper surface, a MEMS mechanism that includes a moving unit that is moved by an external signal, and a part of the first wiring and the second wiring that are provided above the substrate. The first wiring and the second wiring are brought into contact with each other by contacting a region facing at least one of the first wiring and the second wiring by moving the moving portion. And only a part of the contact member facing the first wiring and the second wiring, and at least one region of at least one of the first wiring and the second wiring facing the part. And the thin film is one selected from rhodium, iridium, platinum and ruthenium, or rhodium, iridium, platinum, ruthenium, osmium, gold, silver, copper and palladium. And the first wiring, the second wiring, and the contact member are at least one selected from gold, silver, copper, and aluminum. It is characterized by comprising metal.

  In the MEMS switch, the first switch and the second wiring that are opposed to the first wiring and the second wiring or at least one of the first wiring and the second wiring that are opposed to the first wiring and the second wiring are arranged to face each other. In addition, a protruding portion protruding toward at least one of the first wiring and the second wiring or a part of the contact member may be further provided.

  In the MEMS switch, the thin film may have a thickness of 0.1 μm or less.

  In the MEMS switch, the thickness of the first wiring and the second wiring may be larger than the thickness of the thin film.

  In the MEMS switch, the MEMS mechanism includes a support member that is suspended from the upper surface and connected to the second wiring, and a spring member that extends in the plane direction of the substrate that is supported at one end by the support member. And a movable electrode connected to the other end of the spring member and movable in a direction perpendicular to the planar direction of the substrate, and a movable electrode on the upper surface, opposed to the movable electrode. A control electrode for displacing the moving electrode, the contact member is supported by the moving electrode, and the spring member is made of one or more metals selected from gold, silver, copper, and aluminum You may do it.

  The MEMS switch manufacturing method according to the present invention includes a first switch composed of at least one metal selected from gold, silver, copper, and aluminum on an upper surface of a substrate having at least an upper surface made of an insulating material. A first wiring forming step for forming the wiring of the first wiring, and only one part selected from rhodium, iridium, platinum and ruthenium, or rhodium, iridium, platinum, A thin film forming step of forming a thin film made of a material containing two or more metals selected from ruthenium, osmium, gold, silver, copper, and palladium; and a first substrate on the substrate including the first wiring. A sacrificial film forming step for forming a sacrificial film having an opening that exposes the substrate at a position spaced from the wiring, and whether the gold and silver, copper, and aluminum are on the opening and the sacrificial film. A structure forming step for selectively disposing at least one selected metal to form a structure from the opening to a region above the thin film on the sacrificial film, and at least a sacrificial film removing step for removing the sacrificial film It is characterized by having.

  In another MEMS switch manufacturing method according to the present invention, at least an upper surface is made of at least one metal selected from gold, silver, copper, and aluminum on an upper surface of a substrate made of an insulating material. A first wiring forming step for forming a first wiring; and a sacrificial film forming step for forming a sacrificial film having an opening exposing the substrate at a position spaced apart from the first wiring on the substrate including the first wiring. From among rhodium, iridium, platinum and ruthenium only above a part of the region on the first wiring on the sacrificial film and only on the sacrificial film located above at least a part of the first wiring. Forms a thin film made of a material containing one or more selected metals selected from rhodium, iridium, platinum, ruthenium, osmium, gold, silver, copper, and palladium. Thin film forming step, and a structure in which at least one metal selected from gold, silver, copper, and aluminum is selectively disposed on the opening and the sacrificial film to form a structure from the opening to the thin film It has at least a body forming step and a sacrificial film removing step for removing the sacrificial film.

  In the MEMS switch manufacturing method, the thin film formation step includes a first step of forming a photoresist layer having an opening covering at least a region where the thin film is formed on the upper surface of the substrate, and the substrate on which the photoresist is formed. Above, one selected from rhodium, iridium, platinum and ruthenium, or two or more selected from rhodium, iridium, platinum, ruthenium, osmium, gold, silver, copper and palladium A second step of forming a metal film made of a material containing a metal and a third step of removing the photoresist layer together with the metal film formed thereon by a lift-off method may be used. .

  In the MEMS switch manufacturing method, the first step may be such that an opening is formed in a region other than a region where the first wiring and the structure are formed on the substrate.

  According to the present invention, only a part of the contact member facing the first wiring and the second wiring, and only at least one region of the first wiring and the second wiring facing the part By providing at least one thin film, the distance that a high-frequency signal passes through the thin film is shortened, so that loss in the switch can be reduced.

FIG. 1 is a plan view schematically showing the configuration of the MEMS switch according to the first embodiment of the present invention. 2 is a cross-sectional view taken along the line II of FIG. FIG. 3 is a diagram schematically showing the operation of the MEMS switch according to the first embodiment of the present invention. FIG. 4 is a diagram showing the relationship between the material of the contact metal thin film and the ratio of the adhesion force. FIG. 5 is a diagram showing the relationship between the material of the contact metal thin film and the hardness ratio. FIG. 6 is a cross-sectional view schematically showing a modification of the MEMS switch according to the first embodiment of the present invention. FIG. 7 is a cross-sectional view schematically showing the configuration of the MEMS switch according to the second embodiment of the present invention. FIG. 8 is a cross-sectional view illustrating an operation example of the MEMS switch without the protruding member. FIG. 9 is a cross-sectional view for explaining the operation of the MEMS switch according to the second embodiment of the present invention. FIG. 10 is a cross-sectional view schematically showing a modification of the MEMS switch according to the second embodiment of the present invention. FIG. 11A is a diagram showing a step in the method of manufacturing the MEMS switch shown in FIG. FIG. 11B is a diagram showing a step in the method of manufacturing the MEMS switch shown in FIG. FIG. 11C is a diagram showing a step in the method of manufacturing the MEMS switch shown in FIG. FIG. 11D is a diagram showing a step in the method of manufacturing the MEMS switch shown in FIG. FIG. 11E is a diagram showing a step in the method of manufacturing the MEMS switch shown in FIG. FIG. 11F is a diagram showing a step in the method of manufacturing the MEMS switch shown in FIG. FIG. 11G is a diagram showing a step in the method of manufacturing the MEMS switch shown in FIG. FIG. 11H is a diagram showing a step in the method of manufacturing the MEMS switch shown in FIG. FIG. 11I is a diagram showing a step in the method of manufacturing the MEMS switch shown in FIG. FIG. 11J is a diagram showing a step in the method of manufacturing the MEMS switch shown in FIG. FIG. 11K is a diagram showing a step in the method of manufacturing the MEMS switch shown in FIG. FIG. 11L is a plan view of FIG. 11K. FIG. 11M is a diagram showing a step in the method of manufacturing the MEMS switch shown in FIG. FIG. 11N is a diagram showing a step in the method of manufacturing the MEMS switch shown in FIG. FIG. 12 is a diagram for explaining the effect of lift-off. FIG. 13 is a plan view showing the configuration of the MEMS switch according to the third embodiment of the present invention. 14 is a cross-sectional view taken along line II-II in FIG. 15 is a cross-sectional view taken along line III-III in FIG. FIG. 16 is a cross-sectional view for explaining the operation of the MEMS switch according to the third embodiment of the present invention. FIG. 17 is a cross-sectional view for explaining the operation of the MEMS switch according to the third embodiment of the present invention. FIG. 18 is a plan view showing the configuration of the MEMS switch according to the fourth embodiment of the present invention. 19 is a cross-sectional view taken along line IV-IV in FIG. 20 is a cross-sectional view taken along line VV in FIG. 21 is a cross-sectional view taken along line VI-VI in FIG.

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

[First Embodiment]
First, the MEMS switch according to the first embodiment of the present invention will be described.

<Configuration of MEMS switch>
As shown in FIGS. 1 and 2, the MEMS switch according to the present embodiment includes a substrate 1, a rod-shaped first wiring 2 provided on the substrate 1, and a first wiring 2 on the substrate 1. A second wiring 3 provided on the same straight line as the first wiring 2 and a control electrode 4 provided below a moving electrode 33 (described later) of the second wiring 3. For convenience, the extending direction of the first wiring 2 is “X direction”, the direction perpendicular to the X direction in the plane of the substrate 1 is “Y direction”, and the direction perpendicular to the plane of the substrate 1 is “Z direction”. Say “direction”. Further, in the X direction, the side from the first wiring 2 to the second wiring 3 is defined as a positive side. Similarly, in the Y direction, the upper side with respect to the paper surface of FIG. Similarly, in the Z direction, the side away from the substrate 1 is the upper side or the upper side, and the side approaching the substrate 1 is the lower side or the lower side. Moreover, in FIG. 2, description is abbreviate | omitted except a cut surface.

  The substrate 1 is, for example, a silicon substrate in which an insulating film such as a silicon oxide film is formed on the upper surface (hereinafter referred to as “upper surface”) of the substrate 1, an alumina substrate, a glass substrate, etc. It is comprised from the material which has. As a result, the first wiring 2, the second wiring 3, and the control electrode 4 that are separately provided on the upper surface of the substrate 1 are insulated from each other.

  The first wiring 2 is composed of a rod-shaped member that extends from one end disposed at a substantially central portion of the substrate 1 to the negative side in the X direction and has the other end positioned at the edge of the substrate 1. A contact metal thin film 21 is provided on the upper surface of one end of the first wiring 2. The contact metal thin film 21 is disposed opposite to a contact member 34 of the second wiring 3 described later in the Z direction. Moreover, the edge part of the edge part side of the board | substrate 1 of the 1st wiring 2 is connected to the external circuit by the wiring which is not shown in figure, and the signal exchanged between the 1st wiring 2 and the 2nd wiring 3 is received. , Input or output through the wiring. Such a first wiring 2 is made of a material containing at least one metal selected from gold, silver, copper and aluminum. For the contact metal thin film 21, one selected from rhodium, iridium, platinum, and ruthenium, or rhodium, iridium, platinum, ruthenium, osmium, gold, silver, copper, and palladium is selected. And made of a material containing two or more metals. The material containing two or more metals is made of an alloy.

  The second wiring 3 includes a columnar support member 31 suspended on the substrate 1 and a rod-shaped spring member having one end connected to the upper end of the support member 31 and extending from the one end to the negative side in the X direction. 32, a plate-like moving electrode 33 having a substantially rectangular shape in plan view connected to the other end of the spring member 32, and an end of the moving electrode 33 on the negative side in the X direction. The protruding contact member 34 is provided, and these are integrally formed. Here, the one end of the first wiring 2 is located below the contact member 34. The support member 31 is connected to an external circuit by a wiring (not shown), and a signal exchanged between the first wiring 2 and the second wiring 3 is input or output through the wiring. Further, a driving voltage is supplied to the moving electrode 33 from a control device (not shown). Such a second wiring 3 is made of a material containing at least one metal selected from gold, silver, copper and aluminum.

  The control electrode 4 has the same outer shape as the moving electrode 33 and is provided below the moving electrode 33 on the substrate 1. The control electrode 4 is electrically connected to a control device (not shown), and a drive voltage is supplied from the control device. Such a control electrode 4 is comprised from the material which has electroconductivity, such as Au, Al, Cu, Ni, for example.

  Such a MEMS switch can be manufactured by performing film formation, selective etching, or the like using a known micromachine manufacturing technique.

<Operation of MEMS switch>
Next, the operation of the MEMS switch according to this embodiment will be described.

  When a driving voltage is applied from a control device (not shown) to the moving electrode 33 of the second wiring 3 and the control electrode 4 disposed opposite to the moving electrode 33, electrostatic attraction is caused by a potential difference between the opposed electrodes. appear. Due to the electrostatic attraction, the moving electrode 33 is attracted toward the control electrode 4, and the contact member 34 of the second wiring 3 is also displaced along with this movement. The displacement amounts of the moving electrode 33 and the contact member 34 vary depending on the balance between the electrostatic attractive force and the elastic restoring force of the spring member 32 of the second wiring 3. When the potential difference between the moving electrode 33 and the control electrode 4 is increased, the electrostatic attractive force generated is also increased, and the amount of displacement is also increased. When the potential difference becomes larger than a predetermined value, the lower end of the contact member 34 of the second wiring 3 comes into contact with the first wiring 2 through the contact metal thin film 21 as shown in FIG. As a result, the first wiring 2 and the second wiring 3 become conductive.

  Thus, when the potential difference is made smaller than the predetermined value from the state where the contact member 34 of the second wiring 3 is in contact with the contact metal thin film 21 of the first wiring 2, the spring member 32 of the second wiring 3. Due to the restoring force, the member of the second wiring 3 is moved away from the substrate 1, and the contact member 34 is separated from the first wiring 2. As a result, the first wiring 2 and the second wiring 3 are in a non-conductive state.

  Thus, by changing the potential difference between the moving electrode 33 and the control electrode 4, conduction and non-conduction between the first wiring 2 and the second wiring 3 can be controlled.

  As described above, in the present embodiment, the contact metal thin film 21 is provided only in the portion facing the second wiring 3. This shortens the distance that a high-frequency signal passes through the contact metal thin film 21, thereby reducing the loss in the MEMS switch. In other words, due to the so-called skin effect, the higher the frequency of the high-frequency signal, the more the signal flows through the surface of the conductor, and the switch is more covered when the surface is covered with a highly resistive material than when it is not covered. Loss increases. However, in this embodiment, since the contact metal thin film 21 is provided only in the portion facing the second wiring 3, the distance that a high-frequency signal passes through the contact metal thin film 21 is shortened. Can be prevented from increasing. Further, compared to the case where the contact metal thin film 21 is provided on the entire upper surface of the first wiring 2 as in the prior art, the amount of diffusion of the contact metal thin film 21 on the surface to the inside during the manufacturing process of the MEMS switch is reduced. Therefore, it is possible to prevent the wiring resistivity from increasing, and as a result, it is possible to prevent the loss of the MEMS switch from increasing.

  Further, in the present embodiment, since the contact metal thin film 21 is not provided on the spring member 32, the deformation of the second wiring 3 itself can be suppressed and the fluctuation of the operating voltage can be prevented.

  Here, the smaller the Young's modulus of the material constituting the spring member 32 and the smaller the restoring force that is generated, the lower the drive voltage required to bring the first wiring 2 and the second wiring 3 into contact with each other. it can. As described above, in the present embodiment, since the second wiring 3 is made of a material containing one or more metals selected from gold, silver, copper, and aluminum, the restoration generated by the spring member 32. The force is small and the first wiring 2 and the second wiring 3 can be brought into contact with each other at a low voltage.

  In the present embodiment, the contact metal thin film 21 is one selected from rhodium, iridium, platinum, and ruthenium, or rhodium, iridium, platinum, ruthenium, osmium, gold, silver, copper, Further, by using a material containing two or more metals selected from palladium, the fixing force generated at the contact point between the first wiring 1 and the second wiring 3 is reduced even when high power is passed. be able to.

  As an example, FIG. 4 shows the adhesion force when rhodium is used for the contact metal thin film 21. 4 shows a case where the contact metal thin film 21 is not formed (“gold contact” in FIG. 4), and a case where a 0.02 μm-thick rhodium thin film is formed as the contact metal thin film 21 (“Rh contact ( In the case where a 0.05 μm thick thin film made of rhodium is formed as the contact metal thin film 21 (“Rh contact (film thickness 0.05 μm)” in FIG. 4)), The result of having compared the produced fixing force on the same conditions is shown. As can be seen from FIG. 16, when the contact metal thin film 21 made of rhodium is provided, the fixing force generated at the contact can be reduced by about 2.5 times compared to the case where the contact metal thin film 21 is not provided.

  By providing the contact metal thin film 21 in this way, the adhesive force at the contact can be reduced, so that even a MEMS switch with a low restoring force that can be driven at a low voltage can switch a large power signal. Such an effect is derived from the heat resistance and low adhesion inherent in the material of the contact metal thin film 21, and is considered to be obtained even with a monoatomic film (thickness of about 0.1 nm) of each atom. .

  Further, the insertion loss of the switch can be reduced by setting the thickness of the contact metal thin film 21 to 0.1 μm or less. This is because the material of the contact metal thin film 21 is a metal having a higher resistivity than the material of the first wiring 2 and the second wiring 3. Therefore, the thinner the contact metal thin film 21 is, the more the electric signal has a resistivity. This is considered to be because the distance passing through the high portion is shortened. Furthermore, since the material of the contact metal thin film 21 is harder than the material of the first wiring 2 and the second wiring 3, when the contact metal thin film 21 is formed thick, deformation due to the force pressing the contact is unlikely to occur. For this reason, a contact area is small and the loss in a contact becomes large. On the other hand, when the contact metal thin film 21 is formed thinly, the influence of the soft material constituting the first wiring 2 or the second wiring 3 becomes prominent, and deformation due to the force pressing the contact tends to occur. It is thought that the area was increased and the loss at the contact point was reduced.

  As an example, assuming that the first wiring 2 made of gold is formed in FIG. 5, the rhodium thin film is 0.02 μm thick on the gold itself and the case of gold itself (symbol a in FIG. 5). 5 (symbol b in FIG. 5), a rhodium thin film formed on gold with a thickness of 0.05 μm (symbol c in FIG. 5), and bulk rhodium (symbol d in FIG. 5). The measurement result of hardness is shown. In FIG. 5, normalization is based on the hardness of gold. As shown in FIG. 5, it can be seen that when the thickness of the rhodium thin film is 0.02 μm or 0.05 μm, a value equivalent to the hardness of gold is taken. On the other hand, the bulk rhodium is about 11 times that of gold. Thus, it can be seen that the rhodium thin film is significantly softer than the bulk when the thickness is 0.1 μm or less. This is presumably because the influence of the hardness of the gold underlying the rhodium thin film appears remarkably. Further, it can be seen that 0.02 μm is softer when the rhodium thin film has a thickness of 0.02 μm and 0.05 μm. Thus, the thinner the film thickness, the smaller the hardness of the contact, so that the contact area can be increased and the loss at the contact can be reduced.

  Further, the insertion loss of the switch can be reduced by making the thickness of the first wiring 2 and the second wiring 3 thicker than the contact metal thin film 21. This is probably because the thicker the wiring, the larger the cross-sectional area and the lower the resistance.

  In the present embodiment, the first wiring 2, the second wiring 3, and the contact metal thin film 21 through which an electric signal passes are made of a metal having a low resistivity as described above. Insertion loss can be reduced.

  In the present embodiment, the case where the contact metal thin film 21 is provided on the first wiring 2 has been described as an example. However, the place where the contact metal thin film 21 is provided is not limited to this. For example, the second wiring 3 You may make it provide on top. In addition, as shown in FIG. 6, a contact metal thin film 21 may be provided on both the first wiring 2 and the second wiring 3.

[Second Embodiment]
Next, a second embodiment of the present invention will be described. In the present embodiment, a protruding member is provided on the contact member 34 of the second wiring 3 in the first embodiment, and other configurations are the same as those in the first embodiment. Therefore, in this embodiment, the same name and code | symbol are attached | subjected to the component equivalent to 1st Embodiment, and description is abbreviate | omitted suitably.

  As shown in FIG. 7, the MEMS switch according to the present embodiment is separated from the first wiring 2 on the substrate 1, the rod-shaped first wiring 2 provided on the substrate 1, and the substrate 1. In addition, a second wiring 3 provided on the same straight line as the first wiring 2 and a control electrode 4 provided below a moving electrode 33 (described later) of the second wiring 3 are provided.

  The second wiring 3 includes a columnar support member 31 suspended on the substrate 1 and a rod-shaped spring member having one end connected to the upper end of the support member 31 and extending from the one end to the negative side in the X direction. 32, a plate-like moving electrode 33 having a substantially rectangular shape in plan view connected to the other end of the spring member 32, and an end of the moving electrode 33 on the negative side in the X direction. A protruding contact member 34 and a protruding member 35 protruding from the contact member 34 to the negative side in the Z direction are provided, and these are integrally formed. Here, the projecting member 35 has a columnar shape projecting toward the contact metal thin film 21 of the first wiring 2 disposed so as to be opposed to the center of the lower surface of the contact member 34.

  Here, as shown in FIG. 8, when the projecting member 35 is not provided, when the second wiring 3 is inclined and comes into contact with the first wiring 1, the first metal is formed in a region other than the region where the contact metal thin film 21 is formed. There is a possibility that the wiring 2 and the second wiring 3 come into contact with each other. Therefore, by providing the protruding member 35 as in the present embodiment, the contact metal thin film 21 forms the protruding member 35 even if the operation of the second wiring 3 is inclined as shown in FIG. It is possible to make sure that the contacted area is brought into contact.

  Needless to say, by having the above-described configuration, it is possible to achieve the same operational effects as those of the above-described first embodiment.

<Method for manufacturing MEMS switch>
Further, as shown in FIG. 10, the protruding member 35 may be provided with a contact metal thin film 36 on the surface. A manufacturing method in this case will be described below.

  First, as shown in FIG. 11A, for example, a substrate 1 having a surface formed with an insulating material such as a silicon oxide film or a silicon nitride film is prepared, and a first seed layer 101 is formed on the substrate 1. The first seed layer 101 is formed, for example, by depositing titanium on the substrate 1 and then depositing gold on the titanium by sputtering or vapor deposition. At this time, the thickness of titanium may be about 0.1 μm, and the thickness of gold may be about 0.1 μm.

  When the first seed layer 101 is formed, a resist material is applied on the first seed layer 101 to form a resist film, and the resist film is exposed using a mask having a desired pattern. By developing with an alkaline developer, as shown in FIG. 11B, a first resist pattern 102 having openings 102a and 102b provided at predetermined locations is formed. Further, the first seed layer 101 exposed from the openings 102a and 102b is plated with a material containing at least one metal selected from gold, silver, copper and aluminum by a plating method. 1 wiring 2 and control electrode 4 are formed. Here, the thickness of the first resist pattern is about 2 μm, and the thickness of the first wiring 2 and the control electrode 4 is about 1 μm. After the first wiring 2 and the control electrode 4 are formed, the first resist pattern 102 is removed. As the resist material, for example, “PMER P-series” manufactured by Tokyo Ohka Kogyo Co., Ltd. can be used, and as the alkali developer, for example, “NMD series” manufactured by Tokyo Ohka Kogyo Co., Ltd. can be used.

  When the first resist pattern 102 is removed, as shown in FIG. 11C, the first seed layer 102 is removed using the first wiring 2 and the control electrode 4 as a mask. For this removal, for example, gold on the upper layer of the first seed layer 101 can be removed by wet etching using an etching solution made of iodine, ammonium iodide, water, and ethanol. In addition, titanium below the first seed layer 101 can be removed by wet etching using a hydrogen fluoride aqueous solution.

  When the first seed layer 101 is removed, a resist material is applied to form a resist film, exposed using a mask having a desired pattern, and developed with an alkaline developer, as shown in FIG. 11D. In addition, a second resist pattern in which openings 103a, 103b, and 103c are formed on a substrate 1 spaced apart from a part of the first wiring 2, the control electrode 4, and the first wiring 2 on the negative side in the X direction. 103 is formed. Subsequently, using the second resist pattern 103 as a mask, the metal film 104 is formed, for example, by sputtering, vapor deposition, or plating. Thus, the metal film 104 is formed on the upper surface of the first wiring 2 exposed from the opening 103a, the upper surface of the control electrode 4 exposed from the opening 103b, and the upper surface of the substrate 1 exposed from the opening 103c. The Among these, the metal film 104 formed on the upper surface of the first wiring 2 exposed from the opening 103 a becomes the contact metal thin film 21. The metal film 104 is one selected from rhodium, iridium, platinum, and ruthenium, or 2 selected from rhodium, iridium, platinum, ruthenium, osmium, gold, silver, copper, and palladium. It is composed of a material containing two or more metals. The thickness is about 0.05 μm. In addition, the material containing two or more metals among the materials of the metal thin film 104 is comprised from an alloy.

  As described above, when the step of forming the contact metal thin film 21 is performed immediately after the step of forming the first wiring 2, foreign matter is mixed between the first wiring 2 and the contact metal thin film 21. Therefore, the loss of the MEMS switch can be reduced. This step is omitted when a contact metal film is formed only on the second wiring 3.

  When the metal film 104 is formed, for example, by immersing the substrate 2 in acetone and applying ultrasonic vibration, the second resist pattern 103 is formed thereon as shown in FIG. 11E. The film 104 is removed (lift-off). By forming the contact metal thin film 21 using such a so-called lift-off method, a contact material that is difficult to etch can be easily processed into a desired shape, and a structure can be easily produced. In addition, as shown in FIG. 11D, in the present embodiment, openings 103 b and 103 c are provided in the second resist pattern 102 in addition to the openings 103 a provided on the upper surface of the first wiring 2. This is because, when the second resist pattern 103 is removed by the lift-off method, the etching proceeds from the second resist pattern 103 in the plane direction of the substrate 1, so that only the opening 103a is formed as shown in FIG. If not, it takes a long time to remove all of the second resist pattern 103. Therefore, in the present embodiment, since the three openings 103a to 103c are provided, the time for removing all of the second resist pattern 103 can be shortened.

  When the second resist pattern 103 is removed, as shown in FIG. 11F, the support member 31 for the second wiring 3 is formed on the substrate 1 on which the first wiring 2 provided with the contact metal thin film 21 is formed. A first sacrificial layer 105 made of, for example, an organic resin in which an opening portion 105a is formed at a position where the film is provided. Specifically, for example, a photosensitive organic resin composed of PBO (polybenzoxazole) is coated on the substrate 1 to form a coating film, and the formed coating film is patterned by a known lithography technique. The first sacrificial layer 105 in which the opening 105a is formed can be generated. The thickness of the first sacrificial layer 105 is about 2 μm. As the organic resin used for the first sacrificial layer 105, for example, “CRC8300” manufactured by Sumitomo Bakelite Co., Ltd. can be used. In the sacrificial layer patterning process using “CRC8300”, a pre-bake process at 120 ° C. is performed on the coating film for about 4 minutes as a pre-process. Moreover, after patterning, it is hardened by performing a heat treatment at about 310 ° C.

  When the first sacrificial layer 105 is formed, as shown in FIG. 11G, the position facing the contact metal thin film 21 of the first wiring 2 and the position where the support member 31 of the second wiring 3 is formed. A second sacrificial layer 106 made of, for example, an organic resin having openings 106a and 106b is formed. Here, the second sacrificial layer 106 is formed by a method equivalent to the first sacrificial layer 105 described above. The thickness of the second sacrificial layer is about 1 μm.

  When the second sacrificial layer 106 is formed, a resist material is applied on the second sacrificial layer 106 to form a resist film, and after exposure using a mask having a desired pattern, an alkali developer is used. By developing, as shown in FIG. 11H, a third resist pattern 107 having a position facing the contact metal thin film 21, that is, an opening 107a continuous with the opening 106a is formed. Further, a metal film 108 is formed on the third resist pattern 107 by, for example, sputtering, vapor deposition, or plating. As a result, the metal film 108 is formed around the space formed by the upper surface of the first sacrificial layer 105 and the opening 106 a of the second sacrificial layer 106. The metal film 108 is one selected from rhodium, iridium, platinum, and ruthenium, or two or more selected from rhodium, iridium, platinum, ruthenium, osmium, gold, silver, copper, and palladium. It is made of a material containing any metal. Here, the material containing two or more metals among the materials of the metal thin film 104 is made of an alloy. The thickness of the metal film 108 is about 0.05 μm. The step of forming the metal film 108 is omitted when only the contact metal thin film 21 is formed, that is, when the contact metal thin film 36 is not provided.

  When the metal film 108 is formed, as shown in FIG. 11I, for example, after the substrate 1 is immersed in acetone, ultrasonic vibration is applied to form the third resist pattern 107 on the metal film formed thereon. The entire film 108 is removed. As a result, the metal film 108 to be the contact metal thin film 36 is left in the opening 106 a of the second sacrificial layer 106.

  When the third resist pattern 107 is removed, a second seed layer 109 is formed on the second sacrificial layer 106 as shown in FIG. 11J. The second seed layer 109 is formed by a method equivalent to the first seed layer 101 described above.

  When the second seed layer 109 is formed, a resist material is applied onto the second seed layer 109 to form a resist film, and after exposure using a mask having a predetermined pattern, an alkaline developer is used. By developing, as shown in FIG. 11K which is a plan view of FIGS. 11K and 11K, a fourth resist pattern 110 having an opening 110a at a predetermined location is formed. Further, a material containing at least one metal selected from gold, silver, copper and aluminum is plated on the second seed layer 109 exposed from the opening 110a of the fourth resist pattern 110 by a plating method. As a result, the second wiring 3 is formed. Here, the thickness of the fourth resist pattern 110 is about 2 μm, and the plating thickness of the second wiring 3 is about 1 μm. As shown in FIG. 11L, the planar shape of the opening 110a is formed in a shape corresponding to the support member 31, the spring member 32, the moving electrode 33, and the contact member 34 of the second wiring 3. By plating such an opening 110a, the second wiring 3 is formed in a predetermined shape. When the second wiring 3 is formed, the fourth resist pattern 110 is removed.

  As described above, the step of forming the second wiring 3 is performed immediately after the step of forming the contact metal thin film 36, thereby preventing foreign matter from being mixed between the second wiring 3 and the contact metal thin film 36. As a result, the loss of the MEMS switch can be reduced.

  When the fourth resist pattern 110 is removed, as shown in FIG. 11M, the second seed layer 109 is removed by etching similar to the first seed layer 101 described above using the second wiring 3 as a mask.

  When the second seed layer 109 is removed, the first sacrificial layer 105 and the second sacrificial layer 106 are removed by, for example, ashing using oxygen plasma or an ozone atmosphere, and as shown in FIG. A MEMS switch according to the form is formed.

[Third Embodiment]
Next, a third embodiment of the present invention will be described. In the present embodiment, components equivalent to those in the first and second embodiments described above are denoted by the same names and reference numerals, and description thereof will be omitted as appropriate. In addition, members having the same reference numerals with “′” attached thereto are composed of equivalent materials and have equivalent functions, although there are some changes in shape.

  As shown in FIGS. 13 to 15, the MEMS switch according to the present embodiment includes a substrate 1, a rod-shaped first wiring 2 provided on the substrate, and a distance from the first wiring 2. The rod-shaped second wiring 3 ′ provided on the same straight line as the first wiring 2 is separated from the straight line connecting the first wiring 2 and the second wiring 3 ′ on the substrate 1 and is line symmetric. The first moving mechanism 5 and the second moving mechanism 6 having the same shape provided in the first moving mechanism 5 and a first control provided below the first moving electrode 53 described later of the first moving mechanism 5. A rod-like shape that connects the electrode 7, a second control electrode 8 provided below a second moving electrode 63 (described later) of the second moving mechanism 6, and the first moving mechanism 5 and the second moving mechanism 6. Insulating connecting member 9 and a contact member 10 suspended by the insulating connecting member 9 There.

  The first wiring 2 is composed of a rod-shaped member that extends from one end disposed at a substantially central portion of the substrate 1 to the negative side in the X direction and has the other end positioned at the edge of the substrate 1.

  The second wiring 3 ′ is composed of a rod-shaped member that extends from one end disposed at a substantially central portion of the substrate 1 to the positive side in the X direction and has the other end positioned at the edge of the substrate 1.

  In the first wiring 2 and the second wiring 3 ′, if one is the signal input side and the other is the signal output side, which one is the input side or the output side is arbitrarily set as appropriate. be able to.

  The first moving mechanism 5 includes a columnar first base member 51 suspended on the substrate 1 and one end connected to the upper end of the first base member 51, and from one end to the positive side in the Y direction. A rod-shaped first spring member 52 extending and a plate-like first moving electrode 53 having a substantially rectangular shape in plan view connected to the other end of the first spring member 52 are provided. Is formed. Here, the width of the first spring member 52, that is, the length in the X direction is shorter than the width of the first moving electrode 53 so that the first spring member 52 can be elastically deformed at least in the Z direction. Is formed. In addition, the first moving electrode 53 is disposed so that the side thereof is along the X direction or the Y direction, and at the substantially central portion of the side along the X direction that is disposed to face the second moving mechanism 6. The other end of the first spring member 52 is connected, and is supported by the first spring member 52 so as to be movable in the Z direction. Further, the first moving electrode 53 is disposed to face the first control electrode 7. Further, the first base member 51 is electrically connected to a control device (not shown), and a drive voltage applied from the control device is supplied to the first moving electrode 53. Such a 1st moving mechanism 5 functions as a MEMS mechanism with the 1st control electrode 7, and the 1st moving electrode 53 functions as a moving part.

  The second moving mechanism 6 includes a columnar second base member 61 suspended from the substrate 1 and one end connected to the upper end of the second base member 61 to the negative side in the Y direction. A rod-shaped second spring member 62 and a plate-like second moving electrode 63 having a substantially rectangular shape in plan view to which the other end of the second spring member 62 is connected, and these are integrally formed. Has been. Here, the width of the second spring member 62, that is, the length in the X direction is shorter than the width of the second moving electrode 63 so that the second spring member 62 can be elastically deformed at least in the Z direction. Is formed. In addition, the second moving electrode 63 is disposed so that the side thereof is along the X direction or the Y direction, and at the substantially central portion of the side along the X direction that is disposed to face the first moving mechanism 5. The other end of the second spring member 62 is connected and supported by the second spring member 62 so as to be movable in the Z direction. Further, the second moving electrode 63 is disposed to face the second control electrode 8. Further, the second base member 61 is electrically connected to a control device (not shown), and a drive voltage applied from the control device is supplied to the second moving electrode 63. Such a second moving mechanism 6 functions as a MEMS mechanism together with the second control electrode 8, and the second moving electrode 63 functions as a moving unit.

  The first control electrode 7 has an outer shape equivalent to that of the first moving electrode 53 and is provided on the substrate 1 below the first moving electrode 53. The first control electrode 7 is electrically connected to a control device (not shown), and a drive voltage is supplied from the control device.

  The second control electrode 8 has the same outer shape as the second moving electrode 63, and is provided on the substrate 1 below the second moving electrode 63. The second control electrode 8 is electrically connected to a control device (not shown), and a drive voltage is supplied from the control device.

  The insulating connecting member 9 is composed of a rod-shaped member extending in the Y direction, one end connected to the upper surface of the first moving electrode 53 and the other end connected to the upper surface of the second moving electrode 63. Further, the lower surface of the central portion of the insulating connecting member 9 is connected to the upper surface of the contact member 10. Such an insulating connecting member 9 is made of a rigid body made of an insulating material such as silicon oxide or silicon nitride.

  The contact member 10 is arranged such that one end thereof is opposed to the end portion on the positive side in the X direction in the first wiring 2 and the other end is opposed to the end portion on the negative side in the X direction in the second wiring 3 ′. The center part is comprised from the rod-shaped member extended in the X direction connected to the insulation connection member 9. FIG. Here, on the lower surface of the contact member 10, a contact metal thin film 11 is formed at a position facing the first wiring 2, and a contact metal thin film 12 is formed at a position facing the second wiring 3 '. Such a contact member 10 is made of a material containing at least one metal selected from gold, silver, copper, and aluminum. For the contact metal thin films 11 and 12, one selected from rhodium, iridium, platinum and ruthenium, or rhodium, iridium, platinum, ruthenium, osmium, gold, silver, copper and palladium. It is comprised from the material containing two or more metals selected from these. The material containing two or more metals is made of an alloy. Further, the contact metal thin films 11 and 12 have a thickness of 0.1 μm or less and are smaller than the thicknesses of the first wiring 2 and the second wiring 3 ′.

  Such a MEMS switch can be manufactured by performing film formation or selective etching using a well-known micromachine manufacturing technique.

<Operation of MEMS switch>
Next, the operation of the MEMS switch according to this embodiment will be described.

  From a control device (not shown), the first moving electrode 53 of the first moving mechanism 5, the first control electrode 7 disposed to face the first moving electrode 53, and the second of the second moving mechanism 6 When a drive voltage is applied to each of the movable electrode 63 and the second control electrode 8 disposed opposite to the second movable electrode, the first voltage is generated by electrostatic attraction generated by a potential difference between the opposed electrodes. The movable electrode 53 is pulled toward the first control electrode 7 and the second movable electrode 63 is pulled toward the second control electrode 8. At this time, since the upper surface of the contact member 10 is mechanically connected to the first moving electrode 53 and the second moving electrode 63 by the insulating connecting member 9, the first moving electrode 53 and the second moving electrode are connected. As the electrode 63 moves, it moves together. The amount of displacement in this movement is based on the balance between the electrostatic attraction force and the elastic restoring force of the first spring member 52 of the first moving mechanism 5 and the second spring member 62 of the second moving mechanism 6. Change. That is, the contact member 10 is displaced toward the substrate 1 provided with the first control electrode 7 and the second control electrode 8 so that the electrostatic attraction generated by the potential difference is equal to the restoring force generated by the displacement. In addition, the amount of displacement increases as the potential difference increases and the electrostatic attractive force increases. Therefore, when the potential difference becomes larger than a predetermined value, as shown in FIGS. 16 and 17, the contact member 10 causes the first wiring 2 and the second wiring 3 ′ via the contact metal thin films 11 and 12. To touch. As a result, the first wiring 2 and the second wiring 3 'are brought into conduction.

  Thus, when the contact member 10 is in contact with the first wiring 2 and the second wiring 3 ′ and the potential difference is made smaller than the predetermined value, the first spring member of the first moving mechanism 5 is used. These members are moved away from the substrate 1 by the restoring force of the second spring member 62 of the second moving mechanism 52 and the second moving mechanism 6, and the contact member 10 is separated from the first wiring 2 and the second wiring 3 ′. As a result, the first wiring 2 and the second wiring 3 ′ are brought out of conduction.

  As described above, the first movement electrode 53 of the first movement mechanism 5, the first control electrode 7 disposed to face the first movement electrode 53, and the second movement of the second movement mechanism 6. By changing the potential difference between the electrode 63 and each of the second control electrodes 8 disposed opposite to the second moving electrode, the first wiring 2, the second wiring 3 ′ and the contact member 10 are electrically connected. And non-conduction can be controlled.

  Needless to say, by having the above-described configuration, it is possible to achieve the same operational effects as those of the first and second embodiments described above.

  In addition, according to the present embodiment, when the first wiring 2 and the second wiring 3 ′ are in a non-conductive state, these wirings are cut at at least two places, so that the isolation performance can be improved. it can.

[Fourth Embodiment]
Next, a fourth embodiment of the present invention will be described. In the present embodiment, components equivalent to those in the first to third embodiments described above are denoted by the same names and reference numerals, and description thereof will be omitted as appropriate. In addition, members having the same reference numerals with “'” and “” ”are composed of the same material and have the same function although there are some changes in the shape. ing.

  As shown in FIGS. 18 to 21, the MEMS switch according to the present embodiment includes a substrate 1, a first wiring 2 ′ provided on the substrate, and a distance from the first wiring 2 ′. The second wiring 3 ″ provided on the same straight line as the first wiring 2 ′ is separated from the straight line connecting the first wiring 2 ′ and the second wiring 3 ″ on the substrate 1 and is symmetrical with respect to the line. The first moving mechanism 5 and the second moving mechanism 6 having the same shape provided on the first moving electrode 5 and a first control electrode described later above the first moving electrode 53 described later of the first moving mechanism 5. A second control electrode 8 having a first control electrode 7 ′ having a member 73 and a second control electrode member 83 to be described later above a second movement electrode 63 to be described later of the second moving mechanism 6. And a rod-shaped insulating connecting member 9 that connects the first moving mechanism 5 and the second moving mechanism 6; And an insulating coupling member contact member 10 provided on the 9 '.

  The first wiring 2 ′ is connected to the columnar first base member 25 suspended from the negative edge of the substrate 1 in the X direction, and one end is connected to the upper end of the first base member 26. A rod-shaped first beam member 27 extending from one end toward the substantially central portion of the substrate 1 toward the positive side in the X direction is provided, and these are integrally formed.

  The first wiring 3 ″ is connected to the columnar second base member 36 suspended from the positive edge of the substrate 1 in the X direction, and one end is connected to the upper end of the second base member 36. A rod-shaped second beam member 37 extending from one end toward the substantially central portion of the substrate 1 toward the negative side in the X direction is provided, and these are integrally formed.

  In the first wiring 2 ′ and the second wiring 3 ″, if one is the signal input side and the other is the signal output side, which one is the input side or the output side can be freely set as appropriate. can do.

  The first moving mechanism 5 includes a columnar first base member 51 suspended on the substrate 1 and one end connected to the upper end of the first base member 51, and from one end to the positive side in the Y direction. A rod-shaped first spring member 52 extending and a plate-like first moving electrode 53 having a substantially rectangular shape in plan view connected to the other end of the first spring member 52 are provided. Is formed. Here, the width of the first spring member 52, that is, the length in the X direction is shorter than the width of the first moving electrode 53 so that the first spring member 52 can be elastically deformed at least in the Z direction. Is formed. In addition, the first moving electrode 53 is disposed so that the side thereof is along the X direction or the Y direction, and at the substantially central portion of the side along the X direction that is disposed to face the second moving mechanism 6. The other end of the first spring member 52 is connected, and is supported by the first spring member 52 so as to be movable in the Z direction. Further, the first moving electrode 53 is disposed to face the first control electrode member 73 of the first control electrode 7 ′ provided above the first moving electrode 53. Further, the first base member 51 is electrically connected to a control device (not shown), and a drive voltage applied from the control device is supplied to the first moving electrode 53. Such a first moving mechanism 5 functions as a MEMS mechanism together with the first control electrode 7 ′, and the first moving electrode 53 functions as a moving unit.

  The second moving mechanism 6 includes a columnar second base member 61 suspended from the substrate 1 and one end connected to the upper end of the second base member 61 to the negative side in the Y direction. A rod-shaped second spring member 62 and a plate-like second moving electrode 63 having a substantially rectangular shape in plan view to which the other end of the second spring member 62 is connected, and these are integrally formed. Has been. Here, the width of the second spring member 62, that is, the length in the X direction is shorter than the width of the second moving electrode 63 so that the second spring member 62 can be elastically deformed at least in the Z direction. Is formed. In addition, the second moving electrode 63 is disposed so that the side thereof is along the X direction or the Y direction, and at the substantially central portion of the side along the X direction that is disposed to face the first moving mechanism 5. The other end of the second spring member 62 is connected and supported by the second spring member 62 so as to be movable in the Z direction. The second moving electrode 63 is disposed opposite to the second control electrode member 83 of the second control electrode 8 ′ provided above the second moving electrode 63. Further, the second base member 61 is electrically connected to a control device (not shown), and a drive voltage applied from the control device is supplied to the second moving electrode 63. Such a second moving mechanism 6 functions as a MEMS mechanism together with the second control electrode 8 ′, and the second moving electrode 63 functions as a moving unit.

  The first control electrode 7 ′ is suspended from a plate-like first base member 71 suspended from the edge of the negative side of the substrate 1 in the X direction and the positive side of the substrate 1 in the X direction. The plate-like second base member 72, one end connected to the upper end of the first base member 71, the other end connected to the upper end of the second base member 72, and the plate-like second base member extending along the X direction. 1 control electrode member 73, and these are integrally formed. Such a first control electrode 7 ′ is formed so as to surround both side surfaces and the upper surface in the X direction of the first moving electrode 53. Further, the first control electrode member 73 is disposed to face the first moving electrode 53 disposed below. The first control electrode 7 'is electrically connected to a control device (not shown), and a drive voltage is supplied from the control device.

  The second control electrode 8 ′ is suspended from the plate-like first base member 81 suspended from the edge of the negative side of the substrate 1 in the X direction and the positive side of the substrate 1 in the X direction. A plate-like second base member 82, one end connected to the upper end of the first base member 81, the other end connected to the upper end of the second base member 82, and a plate-like second base member extending along the X direction. 2 control electrode members 83, which are integrally formed. Such a second control electrode 8 ′ is formed so as to surround both side surfaces and the upper surface of the second moving electrode 63 in the X direction. Further, the second control electrode member 83 is disposed opposite to the second moving electrode 63 disposed below. The second control electrode 8 'is electrically connected to a control device (not shown), and a drive voltage is supplied from the control device.

  One end of the insulating connecting member 9 is connected to the lower surface of the first moving electrode 53, and the other end is connected to the lower surface of the second moving electrode 63, and is suspended by the first moving electrode 53 and the second moving electrode 63. , Composed of a rod-shaped member extending in the Y direction. A contact member 10 ′ is provided on the upper surface of the central portion of the insulating connecting member 9. Such an insulating connecting member 9 is made of a rigid body made of an insulating material such as silicon oxide or silicon nitride.

  One end of the contact member 10 ′ is the lower surface of the first beam member 27 on the positive side in the X direction of the first beam 2 ′ in the first wiring 2 ′, and the other end of the second beam member 37 in the second wiring 3 ″. It is composed of a rod-like member extending in the X direction and disposed opposite the lower surface of the negative end portion in the X direction and provided on the upper surface of the insulating connecting member 9. Here, the upper surface of the contact member 10 ′ A contact metal thin film 13 is formed at a position facing the first wiring 2 ′, and a contact metal thin film 14 is formed at a position facing the second wiring 3 ″. Such a contact member 10 'is made of a material containing at least one metal selected from gold, silver, copper, and aluminum. For the contact metal thin films 13, 14, one selected from rhodium, iridium, platinum, and ruthenium, or rhodium, iridium, platinum, ruthenium, osmium, gold, silver, copper, and palladium. It is comprised from the material containing two or more metals selected from these. The material containing two or more metals is made of an alloy. The contact metal thin films 13 and 14 have a thickness of 0.1 μm or less and are smaller than the thicknesses of the first wiring 2 ′ and the second wiring 3 ″.

  Such a MEMS switch can be manufactured by performing film formation or selective etching using a well-known micromachine manufacturing technique.

<Operation of MEMS switch>
Next, the operation of the MEMS switch according to this embodiment will be described.

  From a control device (not shown), the first moving electrode 53 and the first control electrode 7 ′ of the first moving mechanism 5, and the second moving electrode 63 and the second control electrode 8 of the second moving mechanism 6 are used. When a driving voltage is applied to each of ', the first moving electrode 53 is moved to the first control electrode member 73 of the first control electrode 7' by the electrostatic attractive force generated by the potential difference between the electrodes arranged opposite to each other. On the side, the second moving electrode 63 is drawn toward the second control electrode member 83 side of the second control electrode 8 ′. At this time, since the lower surface of the contact member 10 ′ is mechanically connected to the first moving electrode 53 and the second moving electrode 63 by the insulating connecting member 9, the first moving electrode 53 and the second moving electrode 53 As the moving electrode 63 moves, it moves together. The amount of displacement in this movement is based on the balance between the electrostatic attraction force and the elastic restoring force of the first spring member 52 of the first moving mechanism 5 and the second spring member 62 of the second moving mechanism 6. Change. In other words, the contact member 10 ′ is positive in the Z direction in which the first control electrode member 73 and the second control electrode member 83 are provided so that the electrostatic attraction generated by the potential difference is equal to the restoring force generated by the displacement. The amount of displacement also increases as the potential difference increases and the electrostatic attractive force increases. Therefore, when the potential difference becomes larger than a predetermined value, the contact member 10 ′ comes into contact with the first wiring 2 ′ and the second wiring 3 ″ via the contact metal thin films 13 and 14. Thereby, the first wiring 2 ′ and the second wiring 3 ″ are contacted. The first wiring 2 ′ and the second wiring 3 ″ are brought into conduction.

  When the potential difference is made smaller than the predetermined value from the state where the contact member 10 ′ is in contact with the first wiring 2 ′ and the second wiring 3 ″ in this way, the first movement mechanism 5 has the first movement mechanism 5. These members are moved away from the substrate 1 by the restoring force of the spring member 52 and the second spring member 62 of the second moving mechanism 6, and the contact member 10 'is separated from the first wiring 2' and the second wiring 3 ". To do. As a result, the first wiring 2 ′ and the second wiring 3 ″ become non-conductive.

  As described above, the first moving electrode 53 of the first moving mechanism 5, the first control electrode 7 ′ arranged to face the first moving electrode 53, and the second moving mechanism 6 By changing the potential difference between each of the moving electrode 63 and the second control electrode 8 'disposed opposite to the second moving electrode, the first wiring 2', the second wiring 3 "and the contact member are changed. 10 'conduction and non-conduction can be controlled.

  Needless to say, by having the above-described configuration, it is possible to achieve the same operational effects as those of the first to third embodiments described above.

  In addition, according to the present embodiment, when the first wiring 2 ′ and the second wiring 3 ″ are in a non-conductive state, these wirings are cut at at least two places, so that the isolation performance is improved. Can do.

  The present invention can be applied to various microstructures manufactured by MEMS technology or the like, such as a MEMS switch.

  DESCRIPTION OF SYMBOLS 1 ... Board | substrate, 2, 2 '... 1st wiring, 3, 3', 3 "... 2nd wiring, 4 ... Control electrode, 5 ... 1st moving mechanism, 6 ... 2nd moving mechanism, 7, 7 '... first control electrode, 8, 8' ... second control electrode, 9 ... insulating connecting member, 10, 10 '... contact member, 11, 12, 21, 36 ... contact metal thin film, 26 ... first Base member 27 ... first beam member 31 ... support member 32 ... spring member 33 ... moving electrode 34 ... contact member 35 ... projecting member 36 ... second base member 37 ... second Beam member, 41 ... support member, 42 ... beam member, 43 ... contact member, 51 ... first base member, 52 ... first spring member, 53 ... first moving electrode, 61 ... second base member, 62 ... 2nd spring member, 63 ... 2nd moving electrode, 71 ... 1st base member, 72 ... 2nd base member, 73 ... 1st control electrode part , 81 ... first base member, 82 ... second base member, 83 ... second control electrode member.

Claims (9)

A substrate having at least an upper surface made of an insulating material;
First wiring provided at least in part on the upper surface of the substrate;
A second wiring separated from the first wiring and provided at least partially on the upper surface;
A MEMS mechanism including a moving unit that moves by an external signal;
Provided above the substrate, a part thereof is disposed opposite to at least one of the first wiring and the second wiring, and at least one of the first wiring and the second wiring by moving the moving portion A contact member for bringing the first wiring and the second wiring into conduction by bringing the regions facing each other into contact with each other;
Only a part of the contact member facing the first wiring and the second wiring, and at least a region of at least one of the first wiring and the second wiring facing the part A thin film formed into one,
The thin film is one selected from rhodium, iridium, platinum and ruthenium, or two or more selected from rhodium, iridium, platinum, ruthenium, osmium, gold, silver, copper and palladium. Made of materials containing metals,
The MEMS switch, wherein the first wiring, the second wiring, and the contact member are made of at least one metal selected from gold, silver, copper, and aluminum. The MEMS switch according to claim 1, wherein
A part of the contact member that faces the first wiring and the second wiring, or at least one of the first wiring and the second wiring that faces this part, are arranged to face each other. A MEMS switch, further comprising a protruding portion protruding toward at least one of the first wiring and the second wiring or a part of the contact member. The MEMS switch according to claim 1 or 2,
The MEMS switch, wherein the thin film has a thickness of 0.1 μm or less. The MEMS switch according to any one of claims 1 to 3,
The MEMS switch, wherein a thickness of the first wiring and the second wiring is larger than a thickness of the thin film. The MEMS switch according to any one of claims 1 to 4,
The MEMS mechanism is:
A support member suspended from the upper surface of the substrate and connected to the second wiring;
A spring member extending in the planar direction of the substrate, one end of which is supported by the support member;
A moving electrode connected to the other end of the spring member and movable in a direction perpendicular to the planar direction of the substrate;
A control electrode disposed on the upper surface of the substrate so as to face the moving electrode and displacing the moving electrode due to a potential difference generated between the moving electrode, and
The contact member is supported by the moving electrode;
The said spring member is comprised from 1 or more metals chosen from gold | metal | money, silver, copper, and aluminum. The MEMS switch characterized by the above-mentioned. A first wiring forming step of forming a first wiring made of at least one metal selected from gold, silver, copper, and aluminum on the upper surface of the substrate having at least an upper surface made of an insulating material; ,
Only in one region on the first wiring, one selected from rhodium, iridium, platinum and ruthenium, or rhodium, iridium, platinum, ruthenium, osmium, gold, silver, copper, and A thin film forming step of forming a thin film made of a material containing two or more metals selected from palladium;
A sacrificial film forming step of forming a sacrificial film having an opening exposing the substrate at a position separated from the first wiring on the substrate including the first wiring;
At least one metal selected from gold, silver, copper, and aluminum is selectively disposed on the opening and the sacrificial film, and reaches the region above the thin film on the sacrificial film from the opening. A structure forming step for forming the structure;
And a sacrificial film removing step for removing the sacrificial film. A first wiring forming step of forming a first wiring made of at least one metal selected from gold, silver, copper, and aluminum on the upper surface of the substrate having at least an upper surface made of an insulating material; ,
A sacrificial film forming step of forming a sacrificial film having an opening exposing the substrate at a position separated from the first wiring on the substrate including the first wiring;
Of rhodium, iridium, platinum and ruthenium only above a part of the first wiring on the sacrificial film and only on the sacrificial film located above at least a part of the first wiring. A thin film forming a thin film made of a material containing one or more metals selected from rhodium, iridium, platinum, ruthenium, osmium, gold, silver, copper, and palladium. Forming step;
Forming a structure that selectively disposes at least one metal selected from gold, silver, copper, and aluminum on the opening and the sacrificial film to form a structure extending from the opening to the thin film Steps,
And a sacrificial film removing step for removing the sacrificial film. In the manufacturing method of the MEMS switch of Claim 6 or 7,
The thin film forming step includes
A first step of forming a photoresist layer on the upper surface of the substrate having an opening that covers at least a region where the thin film is formed;
On the substrate on which the photoresist is formed, one selected from rhodium, iridium, platinum and ruthenium, or rhodium, iridium, platinum, ruthenium, osmium, gold, silver, copper and palladium. A second step of forming a metal film made of a material containing two or more metals selected from the inside;
And a third step of removing the photoresist layer together with the metal film formed thereon by a lift-off method. The method of manufacturing a MEMS switch according to claim 8,
In the first step, an opening is formed in a region other than a region where the first wiring and the structure are formed on the substrate.

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