JP2012252878A - Contact point, switch and mems relay - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a contact point, a switch and an MEMS relay that can reduce contact resistance and enhance resistance to sticking.SOLUTION: In an MEMS relay as a kind of switch, a contact point 5 comprises nano-period multi-layer film obtained by alternately laminating a first conductive layer 5a and a second conductive layer 5b. The uppermost layer is the first conductive layer 5a. The first conductive layer 5a is formed of a first material selected from the group consisting of Au, Au alloy, Ag, Ag alloy, a composite material of Au or Ag and a different kind of metal, a composite material of Au or Ag and metal oxide, a composite material of Au or Ag and metal nitride, a composite material of Au or Ag and metal sulfide and a composite material of Au or Ag and metal borate, and the second conductive layer 5b is formed of a second material selected from the group consisting of W, Ru, Ir, Rh, IrO, TiB, TiC, ZrB, ZrC, NbC and WC.

Description

  The present invention relates to contacts, switches, and MEMS (micro electro mechanical systems) relays.

  Conventionally, an electromagnetic microrelay provided with an electromagnet device has been known (see, for example, Patent Document 1).

  Patent Document 1 discloses a microrelay including a base substrate provided with a fixed contact on one surface side in the thickness direction, an armature block provided with a movable contact that can be moved toward and away from the fixed contact, and a cover. ing.

  Here, Patent Document 1 describes that a conductive material such as Cr, Ti, Pt, Co, Cu, Ni, Au, or an alloy thereof may be employed as a material for the fixed contact.

  Conventionally, as a laminated film with excellent friction durability compared to a single layer film, a nano-period laminated film that is a laminated film having a structure in which different substances are alternately stacked in nm size, and a thin film that can be expected to have a solid lubricating effect Nano-periodic laminated solid lubricating films, which are laminated films having a thickness of 1 nm, are known (Non-Patent Documents 1 and 2).

  Non-Patent Document 1 describes that according to the nano-period laminated film, the elastic modulus and hardness can be increased as compared with the single-layer film of each laminated material. Non-Patent Document 1 describes a conductive lubricating film in which an Au film and an Ag film are stacked with a nm period, and a conductive lubricating film in which an Au film and a DLC film are stacked with a nm period.

JP 2005-216541 A

Shojiro Miyake, 1 other, “Nano-periodic laminated solid lubricating film”, tribologist, 2008, 53, 11, p. 725-730 Junichi Nojo, two others, “Formation of WS2 / MoS2 / C Solid Lubricating Film and Its Tribological Properties”, Tribologist, 2004, Vol. 49, No. 11, p. 894-900

  In the above-described micro relay, when an open / close test is performed in order to evaluate sticking resistance, sticking in which the movable contact adheres to the fixed contact may occur.

  Therefore, the inventor of the present application relates to a conductive lubricating film in which an Au film and an Ag film described in Non-Patent Document 1 are stacked with a nm period, and a conductive lubricating film in which an Au film and a DLC film are stacked with a nm period. The applicability of the above-described micro relay to movable contacts and fixed contacts was examined.

  However, the inventor of the present application has come to the conclusion that it is inappropriate to employ these conductive lubricating films for the movable contact and the fixed contact of the micro relay.

  This is because, in the above-described micro relay, when a conductive lubricating film in which an Au film and an Ag film are laminated with a period of nm is adopted as a movable contact and a fixed contact, the Au generated due to heat generated during the opening / closing operation. This is because an experimental result has been obtained that the alloy structure of Ag and Ag becomes impossible and the laminated structure cannot be maintained.

  If this point is further demonstrated, this inventor will be able to carry out a movable contact about both the micro relay after performing a switching test, and the micro relay after heating at 450 degreeC, without performing a switching test. The stationary contact was observed with a scanning electron microscope. As a result, it was confirmed that grain growth of AuAg alloy occurred in the former microrelay, and that grain growth of AuAg alloy did not occur in the latter microrelay. In addition, it is known that a metal material such as Au or Ag grows at a temperature of about 80% of the melting point. Therefore, the inventor of the present application estimated that in the above-described micro relay, the temperature of the movable contact and the fixed contact rose to about 800 ° C. to 900 ° C. during opening and closing. In addition, in the above-described micro relay, when a conductive lubricating film in which an Au film and a DLC film are laminated with a period of nm is adopted as a movable contact and a fixed contact, the heat resistance temperature of the DLC film is about 400 ° C. This is because DLC is decomposed due to heat generated during operation, and mechanical characteristics change.

  The present invention has been made in view of the above reasons, and an object of the present invention is to provide a contact, a switch, and a MEMS relay capable of reducing contact resistance and improving sticking resistance. .

The contact of the present invention is a contact made of a nano-period laminate film in which the first conductive layer and the second conductive layer are alternately stacked, and the outermost layer is the first conductive layer, and the first conductive layer is Au, Au alloy, Ag, Ag alloy, composite material of Au or Ag and dissimilar metal, composite material of Au or Ag and metal oxide, composite material of Au or Ag and metal nitride, Au or Ag and metal The second conductive layer is formed of a first material selected from the group consisting of a composite material of sulfide, a composite material of Au or Ag and a metal boride, and the second conductive layer is formed of W, Ru, Ir, Rh, IrO ₂ , TiB. ₂ , TiC, ZrB ₂ , ZrC, NbC, WC, and a second material selected from the group.

  In this contact, the Au alloy is an alloy of Au and at least one metal selected from the group of Ag, Ni, Cu, Pd, Pt, Co, and Zn, and the Ag alloy is Ag, An alloy with at least one metal selected from the group consisting of Au, Ni, Cu and Pd is preferable.

  In this contact, the first conductive layer and the second conductive layer are preferably formed by sputtering.

  The switch according to the present invention includes a movable contact and a fixed contact at which the movable contact comes into contact with or separates, and at least one of the movable contact and the fixed contact includes the contact.

  The MEMS relay according to the present invention includes a base substrate provided with a fixed contact on one surface side in the thickness direction, a cover substrate disposed opposite to the one surface side of the base substrate, and the base substrate and the cover substrate. An electromagnet device housed in one side and a movable part forming substrate disposed between the base substrate and the cover substrate, wherein the movable part forming substrate is interposed between the base substrate and the cover substrate A frame portion, a movable portion disposed inside the frame portion and supported by the frame portion so as to be swingable via a first spring portion, and a magnetic circuit provided with the electromagnet device provided in the movable portion. An armature, and a contact holding portion provided with a movable contact supported by the movable portion and contacting and leaving the fixed contact as the armature swings, the movable contact and the fixed contact, At least one, characterized in that it consists of the contact.

  In the contact according to the present invention, it is possible to reduce the contact resistance and improve the sticking resistance.

  In the switch of the present invention, it is possible to reduce the contact resistance and improve the sticking resistance.

  In the MEMS relay of the present invention, the contact resistance can be reduced and the sticking resistance can be improved.

(A) is a schematic exploded perspective view which shows the MEMS relay of embodiment, (b) is a schematic sectional drawing of a contact. It is a general | schematic disassembled perspective view of the movable part formation board | substrate in the MEMS relay of embodiment. It is a schematic perspective view of the movable part formation board | substrate in the MEMS relay of embodiment. (A) is a schematic top view of the movable part formation board | substrate in the MEMS relay of embodiment, (b) is a principal part schematic sectional drawing of a movable part formation board | substrate, (c) is a principal part schematic bottom view of a movable part formation board | substrate. . It is the schematic perspective view which showed the MEMS relay of embodiment and was seen from the base substrate side.

  In the present embodiment, a relay that is a type of switch is illustrated, but the relay illustrated here is a MEMS relay. Hereinafter, the MEMS relay will be described with reference to FIGS.

  The MEMS relay includes a base substrate 1, a cover substrate 3 arranged to face one surface of the base substrate 1, an electromagnet device 4 stored in a storage portion 16 formed on the base substrate 1, the base substrate 1 and the cover. And a movable part forming substrate 2 disposed between the substrate 3 and the substrate 3. In this MEMS relay, the armature 24 made of a magnetic plate provided on the movable part forming substrate 2 is moved by the electromagnet device 4, whereby the fixed contact 14 provided on the one surface side of the base substrate 1 and the movable part forming substrate. 2 is an electromagnetically driven relay that comes in contact with and separates from the movable contact 27 provided in 2. In the MEMS relay of this embodiment, the outer sizes of the base substrate 1 and the cover substrate 3 are set to the same outer size as that of the movable part forming substrate 2.

  Hereinafter, each component of the MEMS relay will be described in detail.

  The base substrate 1 is formed using a first substrate 10 made of a glass substrate which is a kind of insulating substrate. The first substrate 10 is not limited to a glass substrate, and for example, a high resistivity silicon substrate or a low temperature co-fired ceramic substrate (LTCC substrate) may be used. The glass material of the glass substrate used as the first substrate 10 is borosilicate glass, but is not limited thereto, and soda glass, alkali-free glass, quartz glass, or the like may be used. As the borosilicate glass, for example, Pyrex (registered trademark) or Tempax (registered trademark) can be employed. Moreover, as a high resistivity silicon substrate, for example, when a MEMS relay is used for transmission of a high frequency signal, it is preferable that the resistivity is higher. For example, if the frequency of the high frequency signal to be transmitted is 6 GHz, The rate is preferably 100 Ωcm or more, and more preferably 1000 Ωcm or more. Further, the higher the frequency of the high-frequency signal to be transmitted, the higher the resistivity is preferable.

  The above-described base substrate 1 is formed in a rectangular plate shape, and a pair of signal lines 13 and 13 are formed at both ends in the longitudinal direction of the first substrate 10 on the one surface side. Here, each pair of signal lines 13 and 13 is arranged along the short direction of the first substrate 10 on the one surface side of the base substrate 1. Further, the base substrate 1 is provided with the fixed contact 14 described above at one end of each signal line 13, and the other end of each signal line 13 is penetrated in the thickness direction of the first substrate 10. It is electrically connected to the through-hole wiring 15.

  The signal line 13 is configured by a metal layer (for example, an Au layer). The signal line 13 is made of Au, but is not limited to Au. For example, one type selected from the group of Au, Ni, Cu, Pd, Rh, Pt, Ir, and Os, or an alloy thereof. May be adopted.

  Further, the through-hole 12 (see FIG. 5) in which the above-described through-hole wiring 15 is provided inside the base substrate 1 is a taper whose opening area gradually increases as it approaches the other surface from the one surface of the base substrate 1. It is formed into a shape. Here, the through-hole wiring 15 is formed along the inner surface of the through-hole 12 and closes the through-hole 12 on the one surface side of the base substrate 1.

  Further, the base substrate 1 is formed with a storage portion 16 for storing the electromagnet device 4 as described above. Here, in the base substrate 1, an opening portion 17 that penetrates in the thickness direction and into which the electromagnet device 4 is inserted is formed in the central portion of the first substrate 10. In the base substrate 1, a thin film lid 18 that closes the opening 17 is bonded to one surface of the first substrate 10 on the movable part forming substrate 2 side. In short, in the base substrate 1, the space surrounded by the inner peripheral surface of the opening 17 and the lid body 18 constitutes the storage portion 16. Thereby, the MEMS relay of this embodiment can make the space enclosed by the base substrate 1, the frame part 21 of the movable part forming substrate 2 and the cover substrate 3 an airtight space. Note that Si is used as the material of the lid 18. The thickness of the lid 18 is preferably about 5 μm to 50 μm from the viewpoint of the attractive force that acts on the armature 24 from the electromagnet device 4, and more preferably about 20 μm to 30 μm from the viewpoint of the mechanical strength of the lid 18. .

  The opening 17 has a tapered shape in which the opening area gradually increases as the distance from the one surface of the first substrate 10 approaches the other surface. Thus, the base substrate 1 is easy to insert the electromagnet device 4 from the side opposite to the movable part forming substrate 2 side, and the opening area of the opening 17 on the one surface of the first substrate 10 is relatively small. be able to. In addition, what is necessary is just to form the above-mentioned opening part 17 and the through-hole 12 by the sandblasting method, the etching method, etc., for example.

  The electromagnet device 4 includes a U-shaped yoke 40 and two coils 42 and 42 wound around the yoke 40. The yoke 40 has an elongated rectangular plate-shaped coil winding portion 40a around which both coils 42 and 42 are directly wound, and both ends in the longitudinal direction of the coil winding portion 40a in the thickness direction of the coil winding portion 40a. It has extended side pieces 40b and 40b. In the yoke 40, the tip surfaces of the pair of side pieces 40b, 40b are excited to have different polarities according to the excitation current to the coils 42, 42. The yoke 40 is formed by processing an iron plate such as electromagnetic soft iron by bending, casting, pressing, or the like, and the cross sections of both side pieces 40b, 40b are rectangular.

  In addition, the electromagnet device 4 includes a rectangular plate-like permanent magnet 41 that is disposed between both side pieces 40b, 40b of the yoke 40 so as to overlap the central portion in the longitudinal direction of the coil winding portion 40a. Thus, in the electromagnet device 4, the movement of the coils 42 and 42 in the longitudinal direction of the coil winding portion 40 a is restricted by the permanent magnet 41 and the side pieces 40 b and 40 b of the yoke 40.

  The above-described electromagnet device 4 generates an electromagnetic force when an excitation current is applied to the two coils 42 and 42, and the electromagnetic force causes the rectangular plate-shaped armature 24 to have a longitudinal direction. A suction force for sucking one side and a repulsive force for repelling the other of the both end portions can be generated.

  In the permanent magnet 41, the magnetic pole surfaces on both sides in the thickness direction are magnetized differently, one magnetic pole surface is in contact with the coil winding portion 40a of the yoke 40, and the other magnetic pole surface is on both side pieces of the yoke 40. The thickness dimension is set so as to be located on the same plane as the tip surfaces of 40b and 40b. Here, the above-described electromagnet device 4 is housed in the housing portion 16 in such a manner that the front end surfaces of the both side pieces 40b, 40b of the yoke 40 and the other magnetic pole surface of the permanent magnet 41 abut against the lid body portion 18. . Thus, the other magnetic pole surface of the permanent magnet 41 in the electromagnet device 4 and the front end surfaces of the both side pieces 40b, 40b of the yoke 40 can be positioned on the same plane, so that there is a gap between the electromagnet device 4 and the armature 24. It is possible to improve the accuracy of the gap length.

  In addition, the electromagnet device 4 includes a printed circuit board 43 formed in an elongated rectangular plate shape. In the printed circuit board 43, conductor patterns 43b and 43b are formed at both ends in the longitudinal direction on one surface of the insulating substrate 43a, and the circularly formed portions of the conductor patterns 43b and 43b are for external connection. The electrodes 43ba and 43ba are configured, and the portions formed in a rectangular shape configure the coil connection portions 43bb and 43bb. Here, the terminal of the coils 42 and 42 is connected to the coil connection parts 43bb and 43bb. The coils 42, 42 are configured such that the tip surfaces of the side pieces 40 b, 40 b of the yoke 40 have different magnetic poles when a power source is connected between the external connection electrodes 43 ba, 43 ba and an excitation current is passed through the coils 42, 42. It is connected to the.

The movable part forming substrate 2 is formed using a semiconductor substrate 20 made of a silicon substrate. The semiconductor substrate 20 is not limited to a silicon substrate, for example, an SOI (Silicon On Insulator) substrate having a three-layer structure of silicon layer / insulating layer (SiO ₂ layer) / silicon layer, or silicon layer / insulating layer (SiO ₂ layer). A double SOI substrate having a five-layer structure (double SOI structure) of /) / silicon layer / insulating layer (SiO ₂ layer) / silicon layer may be used.

  The movable portion forming substrate 2 includes a frame portion 21 interposed between the base substrate 1 and the cover substrate 3, and four first spring portions (support spring portions) 22 arranged on the inner side of the frame portion 21. And a movable portion 23 supported so as to be freely swingable. In addition, the movable part forming substrate 2 is arranged between the above-described armature 24 that is arranged on one surface side (electromagnet apparatus 4 side) of the movable part 23 and forms a magnetic circuit together with the electromagnet apparatus 4, and the central part of the armature 24. 23, and a plate 25 arranged with 23 therebetween. Here, the plate 25 is welded to the armature 24 through a through hole 29 penetrating in the thickness direction of the movable portion 23. When the plate 25 is welded to the armature 24, the laser beam is applied to the portion corresponding to the through hole 29 in the plate 25 in a state where the armature 24 is disposed on the one surface side of the movable portion 23 and the plate 25 is disposed on the other surface side. Irradiation causes the plate 25 to be locally melted and welded to the armature 24. In short, the plate 25 is welded to the armature 24 by a laser welding method. In addition, as a laser light source at the time of welding by the laser welding method, for example, a YAG laser may be used. However, the laser light source is not limited thereto, and may be appropriately changed according to the material of the plate 25, for example.

  As the material of the magnetic plate constituting the armature 24, a magnetic material made of an iron-cobalt alloy is adopted, but not limited to this, for example, a magnetic material such as electromagnetic soft iron, electromagnetic stainless steel, and permalloy may be used. That's fine.

  Further, as a material of the plate 25, SUS430 which is a kind of ferritic stainless steel is adopted, but not limited thereto, for example, stainless steel other than SUS430, metal, alloy or the like may be adopted.

  In the movable part forming substrate 2, the thickness of the movable part 23 is smaller than the thickness of the frame part 21, and the thickness of the armature 24 is set so that the movable part forming substrate 2 and the base substrate 1 are fixed. An appropriate gap is formed between the two. The thickness dimension of the plate 25 is set so that an appropriate gap is formed between the movable portion 23 and the cover substrate 3.

  In the present embodiment, the thickness of the frame portion 21 is set to 200 μm, the thickness of the movable portion 23 is set to 50 μm, the thickness of the armature 24 is set to 100 μm, and the thickness of the plate 25 is set to 100 μm. There is no particular limitation. For example, when a silicon substrate is used as the semiconductor substrate 20, it may be appropriately changed according to the thickness of the silicon wafer that is the basis of the silicon substrate, and may be set within a range of, for example, about 50 μm to 1000 μm. Based on the thickness dimension of the substrate 20, the thickness of the movable portion 23, the thickness of the armature 24, and the thickness of the plate 25 may be appropriately changed. However, the thickness dimension of the armature 24 needs to be set so as to ensure a desired attractive force by the electromagnet device 4. On the other hand, the thickness of each of the movable part 23 and the plate 25 is preferably small from the viewpoint of reducing the size of the MEMS relay.

  In the movable part forming substrate 2 described above, the frame part 21 is formed in a rectangular frame shape, and the movable part 23 is formed in a rectangular plate shape. The armature 24 is formed in a rectangular plate shape that is smaller than the movable portion 23. The plate 25 is formed in an elongated plate shape whose longitudinal dimension is slightly larger than the lateral dimension of the movable portion 23, and both end portions in the longitudinal direction are tapered. The plate 25 is arranged at the center in the longitudinal direction of the movable part 23 so that the longitudinal direction of the plate is aligned with the short direction of the movable part 23. In addition, the shape of the plate 25 is not specifically limited, For example, a rectangular shape may be sufficient and a rhombus shape may be sufficient.

  The first spring portion 22 is formed at two locations spaced apart in the longitudinal direction of the movable portion 23 on each side edge side of the movable portion 23 in the lateral direction. Each first spring portion 22 has one end connected to the movable portion 23 and the other end connected to the inner peripheral surface of the frame portion 21. Each of the first spring portions 22 has a long dimension by forming a portion between the one end portion and the other end portion in a planar shape so as to meander in the same plane. Thereby, the movable part forming substrate 2 can disperse the stress generated in each of the first spring parts 22 when the movable part 23 swings, and the first spring parts 22 are damaged. Can be suppressed.

  Further, the movable part forming substrate 2 is provided with one rectangular first projecting piece 23 a extending from the central part of each side edge of the movable part 23 in the short direction. The movable part forming substrate 2 has one rectangular second projecting piece 21 a extending from each part corresponding to each first projecting piece 23 a of the movable part 23 on the inner peripheral surface of the frame part 21. Has been. That is, the movable portion forming substrate 2 has the front end surfaces of the first projecting piece 23a and the second projecting piece 21a corresponding to each other one-to-one. Here, a convex portion 23 b is formed on each tip surface of each first protruding piece 23 a extending from the movable portion 23. On the other hand, a concave portion 21b into which the convex portion 23b enters is formed on each tip surface of each second protruding piece 21a extending from the frame portion 21. Therefore, in the movable part forming substrate 2, the movement of the movable part 23 in the plane orthogonal to the thickness direction of the frame part 21 is restricted by the convex part 23b coming into contact with the inner peripheral surface of the concave part 21b. The two first spring portions 22 on the same side edge side of the movable portion 23 are located on both sides of the first projecting piece 23a extending from the same side edge.

  The movable part forming substrate 2 is provided with a fulcrum protrusion 23c (see FIG. 2) on the surface of the first protruding piece 23a of the movable part 23 facing the base substrate 1. The fulcrum protrusion 23 c functions as a fulcrum when the movable part 23 swings (rotates) together with the armature 24 integrated with the movable part 23. In short, in the movable part forming substrate 2, two fulcrum protrusions 23c arranged apart from each other in the short direction of the movable part 23 are in contact with the one surface of the base substrate 1, and the pair of fulcrum protrusions 23c and 23c are connected to each other. The connecting straight line can be turned around a turning axis.

  Further, the movable part forming substrate 2 is provided with rectangular third protrusions 23d extending from the four corners of the movable part 23 toward both sides of the movable part 23 in the short direction, and a base in each third protrusion 23d. A stopper portion 23e (see FIG. 2) that restricts the swing range of the movable portion 23 is formed on the surface facing the substrate 1. These stopper portions 23 e limit the amount of displacement of the movable portion 23 by coming into contact with the one surface of the base substrate 1. As a result, the MEMS relay can avoid contact between the armature 24 and the lid portion 18, and can prevent the armature 24 and the lid portion 18 from being damaged.

  In the movable part forming substrate 2, contact holding parts 28 and 28 are arranged on both sides of the movable part 23 in the longitudinal direction. Each contact holding portion 28 is supported by the movable portion 23 via a pair of second spring portions (contact pressure spring portions) 26 and 26. Each contact holding portion 28 is provided with a movable contact 27 (see FIG. 2) that contacts and separates a pair of fixed contacts 14 and 14 that face each other in the thickness direction of the base substrate 1.

  The thickness dimension of each contact holding part 28 is set to a value smaller than the thickness dimension of the frame part 21 and smaller than the thickness dimension of the movable part 23. Further, the thickness dimension of the contact holding portion 28 and the movable contact 27 that overlap in the thickness direction of the contact holding portion 28 is also set to a value that satisfies such a condition. Each contact holding part 28 has a rectangular shape in plan view, and is arranged such that the short side direction coincides with the longitudinal direction of the movable part 23.

  Each second spring part 26 has one end connected to the side edge along the longitudinal direction of the movable part 23 and the other end connected to the side edge along the short direction of the contact holding part 28. A part of the intermediate part between the one end and the other end is meandered in a plane perpendicular to the thickness direction of the movable part 23. Moreover, the length of each 2nd spring part 26 is made the same. Thus, in the MEMS relay of the present embodiment, the pair of springs corresponding to each movable contact 27 is set by appropriately setting the spring force of each second spring part 26 with the length of each second spring part 26 being an appropriate length. The contact pressure with the fixed contacts 14 and 14 can be set to a desired magnitude, and the contact reliability between each movable contact 27 and the corresponding pair of fixed contacts 14 and 14 can be improved. .

  In the movable portion forming substrate 2, the frame portion 21 is bonded to the base substrate 1 and the cover substrate 3. Thereby, the movable part forming substrate 2 is displaced between a position where each movable contact 27 faces the corresponding pair of fixed contacts 14, 14 and short-circuits between the pair of fixed contacts 14, 14 and an open position. It is possible. Here, for simplicity of explanation, the pair of fixed contacts 14 and 14 positioned on the right side in FIG. 1A corresponds to the pair of first fixed contacts 14a and 14a and the first fixed contacts 14a and 14a. The movable contact 27 to be operated corresponds to the first movable contact 27a, and the pair of fixed contacts 14 and 14 located on the left side in FIG. 1A corresponds to the pair of second fixed contacts 14b and 14b and the second fixed contacts 14b and 14b. The movable contact 27 to be performed may be referred to as a second movable contact 27b.

  In the movable part forming substrate 2, the first movable contact 27 a short-circuits between the pair of first fixed contacts 14 a and 14 a and the second movable contact 27 b is a pair of second fixed as the armature 24 operates (swings). The first state where the contacts 14b and 14b are opened, the first movable contact 27a opens between the pair of first fixed contacts 14a and 14a, and the second movable contact 27b extends between the pair of second fixed contacts 14b and 14b. The short-circuited second state appears alternately.

  Here, if the above-described double SOI substrate is used as the semiconductor substrate 20 that is the basis of the movable portion forming substrate 2, the distance between the movable portion 23 and the base substrate 1 is defined by the thickness of the silicon layer on the base substrate 1 side. Is possible. As a result, the MEMS relay sets the distance (insulating distance) between the movable contact 27 and the pair of fixed contacts 14 and 14 in a state where the pair of fixed contacts 14 and 14 corresponding to the movable contact 27 are opened. It becomes possible to set with high accuracy, and it becomes possible to set the distance (magnetic gap length) between the armature 24 and the electromagnet device 4 with high accuracy.

  Further, the cover substrate 3 is formed by using the second substrate 30 made of a glass substrate. However, the second substrate 30 is not limited to the glass substrate, but has a high resistivity, like the first substrate 10. Alternatively, a silicon substrate or an LTCC substrate may be used.

  The cover substrate 3 is provided with a recess (not shown) that secures a swinging space for the movable portion 23 on the surface facing the movable portion forming substrate 2.

  Here, the operation of the MEMS relay of this embodiment will be described.

  In the MEMS relay of this embodiment, when the coils 42 are energized, one end portion in the longitudinal direction of the armature 24 is attracted to one side piece 40 b of the yoke 40 according to the direction of magnetization. As a result, the MEMS relay contacts the pair of fixed contacts 14, 14 corresponding to the movable contact 27 near the one end of the armature 24, and the pair of movable contacts 27 corresponding to the other end of the armature 24. It will be in the state away from the fixed contacts 14 and 14. In this state, even if energization of the coils 42, 42 is stopped, the attractive force to the one end of the armature 24 is maintained by the magnetic flux generated by the permanent magnet 41, and the movable contact 27 close to the one end of the armature 24. And a pair of corresponding fixed contacts 14 and 14 are kept in contact with each other.

  Further, in the MEMS relay of the present embodiment, when the energization direction to the coils 42 is reversed, the other end portion in the longitudinal direction of the armature 24 is attracted to the other side piece 40b of the yoke 40, and the armature 24 The movable contact 27 close to the other end contacts the corresponding pair of fixed contacts 14 and 14, and the movable contact 27 close to the one end of the armature 24 leaves the corresponding pair of fixed contacts 14 and 14. It becomes. In this state, even if energization of the coils 42 and 42 is stopped, the attractive force to the other end of the armature 24 is maintained by the magnetic flux generated by the permanent magnet 41, and the armature 24 is movable close to the other end. The state where the contact 27 and the corresponding pair of fixed contacts 14 and 14 are in contact with each other is maintained.

  Note that the MEMS relay of this embodiment uses a polarized electromagnet device having a permanent magnet 41 as the electromagnet device 4 that moves the armature 24, and therefore constitutes a latching type relay (micro relay). . However, the MEMS relay may use a non-polar electromagnet device that does not include the permanent magnet 41 as the electromagnet device 4.

  The frame portion 21 of the above-described movable portion forming substrate 2 is bonded to the base substrate 1 and the cover substrate 3 by an anodic bonding method.

  The movable portion 23 has two through holes 29 described above. These two through holes 29 are formed side by side on the center line along the short direction of the movable part 23 at the center in the longitudinal direction of the movable part 23. Each through-hole 29 has a circular opening shape. On the other hand, the dimension of the longitudinal direction of the plate 25 is set to a value larger than the dimension of the movable part 23 in the lateral direction. Further, the plate 25 is set such that the dimension in the short direction at the intermediate portion in the longitudinal direction is larger than the inner diameter of the through hole 29. In addition, the opening shape of each through-hole 29 is not specifically limited. In short, the dimension in the short direction of the plate 25 may be a value larger than the maximum dimension of the through hole 29 on the other surface of the movable part 23 (maximum dimension of the through hole 29 in the longitudinal direction of the movable part 23).

  The plate 25 is welded to the armature 24 through each through hole 29 of the movable portion 23. In short, the plate 25 is welded to the armature 24 at two locations. In addition, a welding location is not limited to two locations.

  By the way, in the movable part forming substrate 2, the part including the movable part 23, the armature 24, and the plate 25 is symmetric with respect to the center line along the short direction of the movable part 23, and the longitudinal direction of the movable part 23. The arrangement area of the armature 24 on the one surface of the movable part 23 is defined so as to be symmetric with respect to the center line along the center line, and the arrangement area of the plate 25 on the other surface of the movable part 23 is defined. In short, in the MEMS relay of the present embodiment, the above-described arrangement regions are defined so that the center of gravity of the movable portion 23 and the center of gravity of each of the armature 24 and the plate 25 are positioned on a straight line. Further, in the movable part forming substrate 2, the entire block inside the frame part 21 is symmetrical with respect to the center line along the short direction of the movable part 23, and the center line along the longitudinal direction of the movable part 23. The shape and arrangement of each first spring part 22, each second spring part 26, and each contact holding part 28 are defined so as to be symmetrical with respect to each other.

  Further, the movable part forming substrate 2 positions the movable part 23 on the movable part 23 from the one surface of the movable part 23 and positions the armature 24, and projects from the other surface of the movable part 23 to position the plate 25. The second protrusion 23f is integrally provided.

  The protrusion dimension of the first protrusion 23g is preferably smaller than the thickness dimension of the armature 24 so that the first protrusion 23g does not narrow the swing range of the armature 24. For example, when the thickness dimension of the armature 24 is 100 μm, it is sufficient that the projecting dimension of the first protrusion 23 g is about 10 μm. These numerical values are merely examples, and are not particularly limited.

  The projecting dimension of the second protrusion 23 f is preferably smaller than the thickness dimension of the plate 25 so that the second protrusion 23 f does not narrow the swing range of the plate 25. For example, when the thickness dimension of the plate 25 is 100 μm, it is sufficient that the projecting dimension of the second protrusion 23 f is about 10 μm. These numerical values are merely examples, and are not particularly limited.

  Further, the movable part forming substrate 2 includes a plurality of first protrusions 23g and second protrusions 23f, and the plurality of first protrusions 23g surround a prescribed arrangement region of the armature 24 on the one surface side of the movable part 23. It is preferable that the plurality of second protrusions 23f are arranged so as to surround a prescribed arrangement region of the plate 25 on the other surface side of the movable portion 23. In short, in the movable part forming substrate 2, the plurality of first protrusions 23 g are arranged along the outer periphery of the armature 24, and the plurality of second protrusions 23 f are arranged along the outer periphery of the plate 25. In the present embodiment, the number of the first protrusions 23g is eight and the number of the second protrusions 23f is six. However, these numbers are not particularly limited. However, the first protrusion 23g is arranged symmetrically with respect to the center line along the short direction of the movable portion 23 on the one surface side of the movable portion 23, and the center along the longitudinal direction of the movable portion 23. It is preferable that they are arranged symmetrically with respect to the line. Further, the second protrusions 23f are arranged symmetrically with respect to the center line along the short direction of the movable part 23 on the other surface side of the movable part 23 and along the longitudinal direction of the movable part 23. It is preferable that they are arranged symmetrically with respect to the center line. Each first protrusion 23g and each second protrusion 23f has a rectangular planar shape, but these shapes are not limited to a rectangular shape, and may be, for example, a circular shape, a triangular shape, or a polygonal shape. Further, the plurality of first protrusions 23g need not all have the same shape. Further, the plurality of second protrusions 23f need not all have the same shape. Further, the first protrusion 23g may be only one as a frame shape surrounding the prescribed arrangement region of the armature 24 on the one surface side of the movable portion 23. Further, the second protrusion 23f may be only one as a frame-like shape surrounding the prescribed arrangement region of the plate 25 on the other surface side of the movable portion 23. Further, the formation position of the first protrusion 23g is designed so as to provide a predetermined first gap (for example, about 10 μm) between the first protrusion 23g and a predetermined arrangement region of the armature 24. As a result, the armature 24 can be easily arranged, and it is possible to suppress the occurrence of a problem that the armature 24 cannot be arranged due to the dimensional tolerance of the armature 24 or the like. Further, the formation position of the second protrusion 23 f is designed so as to provide a predetermined second gap (for example, about 10 μm) between the second protrusion 23 f and a predetermined arrangement region of the plate 25. Thereby, the arrangement of the plate 25 is facilitated, and it is possible to suppress the occurrence of a problem that the plate 25 cannot be arranged due to the dimensional tolerance of the plate 25 or the like.

  The above-described armature 24 and plate 25 are each formed using a machining technique such as punching. The armature 24 and the plate 25 are arranged with respect to the movable part 23 by a vacuum chuck or the like.

  On the other hand, the movable part forming substrate 2 is formed by using the micromachining technique for components other than the armature 24 and the plate 25. That is, the frame part 21 of the movable part formation board 2, the movable part 23, each 1st spring part 22, each 1st protrusion piece 23a, the 2nd protrusion piece 21a, each 2nd spring part 26, each contact holding | maintenance part 28, each The first protrusions 23g and the respective second protrusions 23f are formed by processing the semiconductor substrate 20 (the wafer serving as the basis of the semiconductor substrate 20) using a semiconductor process technique such as a photolithography technique or an etching technique. . Therefore, the positional accuracy of each first protrusion 23g with respect to the movable portion 23 is mainly due to the overlay of the overlay detection mark in the exposure process when each first protrusion 23g is formed using a photolithography technique and an etching technique. It depends on the accuracy (overlay accuracy) and the dimensional shift (measureshift) in the etching process.

  In order to weld the armature 24 and the plate 25, for example, the armature 24 is first positioned with respect to the movable portion 23, and then the armature 24 or the movable portion 23 is sucked by a vacuum chuck or the like, and then movable. The plate 25 is positioned with respect to the portion 23. Subsequently, a portion of the plate 25 corresponding to the through hole 29 of the movable portion 23 may be irradiated with laser light to locally melt the plate 25 and weld the plate 25 and the armature 24.

  By the way, each of the above-mentioned fixed contact 14 and movable contact 27 is a contact comprising a nano-period laminated film in which the first conductive layer 5a and the second conductive layer 5b are alternately laminated as shown in FIG. 5.

The contact 5 has the first conductive layer 5a as the outermost layer, and the first conductive layer 5a is Au, Au alloy, Ag, Ag alloy, composite material of Au or Ag and dissimilar metal, Au or Ag and metal oxide. A first material selected from the group consisting of: a composite material of Au or Ag and a metal nitride; a composite material of Au or Ag and a metal sulfide; a composite material of Au or Ag and a metal boride The second conductive layer 5b is formed of a second material selected from the group consisting of W, Ru, Ir, Rh, IrO ₂ , TiB ₂ , TiC, ZrB ₂ , ZrC, NbC, and WC. Here, the second material may be an inorganic material that is not alloyed with Au or Ag and has electrical conductivity, and a material that is not included in the above group may be employed.

  The Au alloy described above is preferably an alloy of Au and at least one metal selected from the group of Ag, Ni, Cu, Pd, Pt, Co, and Zn. An alloy of Ag and at least one metal selected from the group consisting of Au, Ni, Cu, and Pd is preferable. By adopting these Au alloys, the hardness becomes higher and the sticking resistance can be improved as compared with the case of employing other Au alloys. Further, by employing these Ag alloys, the hardness is increased and sticking resistance can be improved as compared with the case of employing other Ag alloys.

  The thickness of the first conductive layer 5a and the second conductive layer 5b is preferably set within the range of the thickness of one molecular layer to 10 nm. A group of strain energy generated between the first conductive layer 5a and the second conductive layer 5b extends over the whole thickness direction of the nano-period multilayer film, and the hardness and elastic modulus of the nano-period multilayer film are the first conductive layer. It becomes higher than the case of 5a alone or the second conductive layer 5b alone, and the sticking resistance is improved.

  Regarding the thickness of each molecular layer of each of the first conductive layer 5a and the second conductive layer 5b, when each of the first conductive layer 5a and the second conductive layer 5b is composed of a single metal, each atom of each metal It is preferable to make it the same value as the diameter. If the thickness of the first conductive layer 5a and the second conductive layer 5b is set to be thinner than the thickness of one molecular layer, each of the first conductive layer 5a and the second conductive layer 5b is unlikely to be a film, and strain energy Does not reach the entire thickness of the nano-period laminate film. For this reason, there is a high possibility that the effect that the hardness and elastic modulus of the nano-period multilayer film are higher than those of the first conductive layer 5a alone or the second conductive layer 5b alone cannot be obtained.

Further, when the thickness of the first conductive layer 5a and the second conductive layer 5b is set to be thicker than 10 nm, the strain energy does not reach the entire thickness of the nano-period laminated film. For this reason, there is a high possibility that the effect that the hardness and elastic modulus of the nano-period multilayer film are higher than those of the first conductive layer 5a alone or the second conductive layer 5b alone cannot be obtained. Further, when metal grains grow due to the temperature rise of the first conductive layer 5a and the second conductive layer 5b, the size of the metal grains in the thickness direction of the nano-period laminated film is the first conductive layer 5a and the second conductive layer. The thickness of each layer 5b becomes a limit value. In short, in the above-described MEMS relay, the particles of the metal material in the thickness direction of each of the first conductive layer 5a and the second conductive layer 5b due to a temperature rise caused by the opening and closing of the contact portion constituted by the movable contact 27 and the fixed contact 14 are performed. Growth is limited by the thickness of each of the first conductive layer 5a and the second conductive layer 5b. Also, the contact 5, the second conductive layer 5b _{is, W, Ru, Ir, Rh} , IrO 2, TiB 2, TiC, ZrB 2, ZrC, NbC, are formed by a second material selected from the group of WC Therefore, it is difficult to diffuse into the first conductive layer 5a formed of the above-mentioned first material, and the laminated structure of the nano-period laminated film is maintained even when the temperature rises. Therefore, the contact 5 is suppressed from lowering the interparticle strength of the metal material structure, and is less likely to cause transition due to shearing. On the other hand, when the thickness of at least one of the first conductive layer 5a and the second conductive layer 5b exceeds 10 μm, the interparticle strength decreases greatly, and it becomes difficult to suppress the shear fracture of the metal material structure.

  The second conductive layer 5b is made of the second material described above, and the electrical resistivity of W, Ru, Ir, Rh, Ti, Zr, Nb, and W is higher than that of Au or Ag. Although it is high, the thickness is 10 nm or less, and since it is thin, electrons flow in the thickness direction by the tunnel effect. Therefore, the contact 5 can reduce the electrical resistivity in the thickness direction of the nano-period laminated film. Here, when the thickness of the second conductive layer 5b exceeds 10 nm, the tunnel effect is reduced and the electrical resistivity of the contact 5 is increased.

The second conductive layer 5b, as described above, to form _{W, Ru, Ir, Rh,} IrO 2, TiB 2, TiC, ZrB 2, ZrC, NbC, the second material selected from the group of WC It is preferable. In short, the second conductive layer 5b may be formed of a metal made of at least one of W, Ru, Ir, and Rh, or IrO ₂ , TiB ₂ , TiC, ZrB ₂ , ZrC, NbC, and WC. You may form with the metal compound which consists of 1 type. When the second conductive layer 5b is formed of a metallized mineral, the strain energy between the second conductive layer 5b and the first conductive layer 5a is larger, and the hardness and elastic modulus are higher than when formed by a metal. Therefore, further improvement in sticking resistance can be expected.

  In the contact 5, the first conductive layer 5a is formed of the first material described above, and the outermost layer of the nano-period multilayer film is the first conductive layer 5a, so that the contact resistance can be reduced.

  The first conductive layer 5a and the second conductive layer 5b are preferably formed by sputtering. If the first conductive layer 5a and the second conductive layer 5b are formed by sputtering, each of the first conductive layer 5a and the second conductive layer 5b is compared with the case where they are formed by vapor deposition or electroplating. The thickness can be easily controlled and the nano-period laminated film can be easily manufactured. Since the first conductive layer 5a and the second conductive layer 5b are formed by the sputtering method, the contact 5 has the first conductive layer 5a and the second conductive layer 5a compared to the case where the contact 5 is formed by a vapor deposition method or an electroplating method. It becomes possible to improve the accuracy of the thickness of each of the two conductive layers 5b. In addition, when forming the 1st conductive layer 5a and the 2nd conductive layer 5b by sputtering method, nano period is controlled by controlling the opening and closing speed of the shutter between the target and the substrate holder, and the rotation speed of the substrate holder. It becomes possible to form the contact 5 made of a laminated film.

  Hereinafter, the contacts 5 of Examples 1 to 8 and Comparative Examples 1 to 3 in which the combination of the first material and the second material and the combination of the thicknesses of the first conductive layer 5a and the second conductive layer 5b are variously changed. Table 1 shows the results of evaluating the sticking resistance and the contact resistance. The contact 5 was made of silicon as a base material, a film thickness of 4 μm, and a plane size of 1 mm □.

  In evaluating the sticking resistance, the contact portion constituted by the contacts 5 of the same example was opened and closed, and the presence or absence of sticking (stick generation) was observed with a microscope. Here, the switching conditions were no current load, speed of 0.01 m / s, switching rate of 10 Hz, and contact load of 0.1 mg.

  In the evaluation of contact resistance, after the contact part was opened and closed 1000 times, the contact part resistance was measured in a state where the contacts 5 were in contact with each other, and the value obtained by subtracting the wiring resistance from the measurement result was used as the contact resistance. It was.

  From Table 1, it can be seen that the sticking resistance of the contacts 5 of Examples 1 to 8 is improved as compared to the contacts 5 of Comparative Examples 1 to 3. Moreover, in Examples 1-8, compared with the comparative example 3, it turns out that low contact resistance can be aimed at. Further, from the comparison between the comparative example 2 and the comparative example 3, in the comparative example 2 in which the thickness of the second conductive layer 5b is set within the above-mentioned range, compared with the comparative example 3 set outside the range, the low contact It can be seen that resistance can be achieved.

The contact 5 in the present embodiment described above is composed of a nano-period laminated film in which the first conductive layer 5a and the second conductive layer 5b are alternately stacked, the outermost layer is the first conductive layer 5a, and the first conductive layer Layer 5a is made of Au, Au alloy, Ag, Ag alloy, Au or a composite material of Ag and a dissimilar metal, Au or a composite material of Ag and a metal oxide, a composite material of Au or Ag and a metal nitride, Au Or formed of a first material selected from the group consisting of a composite material of Ag and a metal sulfide, a composite material of Au or Ag and a metal boride, and the second conductive layer 5b includes W, Ru, Ir, Rh, The second material is selected from the group consisting of IrO ₂ , TiB ₂ , TiC, ZrB ₂ , ZrC, NbC, and WC. Therefore, in the contact 5, it is possible to reduce the contact resistance and improve the sticking resistance.

  Further, the MEMS relay of the present embodiment includes a base substrate 1 provided with a fixed contact 14 on one surface side in the thickness direction, a cover substrate 3 disposed to face the one surface side of the base substrate 1, and the base substrate 1. And a movable part forming substrate 2 disposed between the base substrate 1 and the cover substrate 3. Further, in this MEMS relay, the movable part forming substrate 2 is disposed between the base substrate 1 and the cover substrate 3, the frame part 21 is disposed inside the frame part 21, and the first spring part 22 is provided on the frame part 21. A movable part 23 supported by the movable part 23, an armature 24 provided on the movable part 23 and constituting a magnetic circuit together with the electromagnet device 4, and the fixed contact 14 supported by the movable part 23 as the armature 24 swings. And a contact holding portion 28 provided with a movable contact 27 that contacts and separates from the contact. In the MEMS relay, each of the movable contact 27 and the fixed contact 14 is constituted by the contact 5 described above. Therefore, in the MEMS relay of this embodiment, it is possible to reduce the contact resistance of the contact portion constituted by the movable contact 27 and the fixed contact 14 and to improve the sticking resistance. In the MEMS relay of the present embodiment, both the movable contact 27 and the fixed contact 14 are configured by the above-described contact 5, but at least one of them is configured by the above-described contact 5, thereby reducing the low contact resistance of the contact portion. And the sticking resistance can be improved. In addition to this MEMS relay, in a switch provided with a movable contact and a fixed contact, at least one of the movable contact and the fixed contact is configured by the contact 5 described above, thereby reducing the contact resistance of the contact portion. It is possible to improve sticking resistance.

  In the above-described MEMS relay, the storage unit 16 that stores the electromagnet device 4 is formed on the base substrate 1. However, the present invention is not limited to this. For example, the storage unit that stores the electromagnet device 4 is formed on the cover substrate 3. It is good. In the MEMS relay in which the storage unit for storing the electromagnet device 4 is formed on the cover substrate 3, the electromagnet device 4 and the signal lines 13 and 13 are compared with the case where the storage unit 16 for storing the electromagnet device 4 is provided on the base substrate 1. Therefore, it is possible to suppress the occurrence of transmission loss due to the influence of the magnetic flux generated by the electromagnet device 4. In addition, according to the MEMS relay in which the housing portion is formed on the cover substrate 3, the thickness dimension of the base substrate 1 can be reduced as compared with the case where the electromagnet device 4 is accommodated in the base substrate 1. Since the length of 15 can be shortened, the high frequency characteristics can be improved.

  In the MEMS relay described in the above-described embodiment, two movable contacts 27 and a pair of fixed contacts 14 and 14 corresponding to each movable contact 27 are provided. The number of contacts 14 is not limited to 1: 2, but may be, for example, 1: 1. Further, the number of sets of the movable contact 27 and the corresponding fixed contact 14 is not limited to two, and may be one.

  In the above-described embodiment, the electromagnetic drive type MEMS relay is exemplified as the MEMS relay. However, the present invention is not limited to this, and for example, an electrostatic drive type MEMS relay or a piezoelectric drive type MEMS relay may be used. Moreover, a relay is not limited to a MEMS relay.

  Moreover, a switch is not restricted to a relay, For example, a MEMS switch, an electrical switch, etc. may be sufficient.

DESCRIPTION OF SYMBOLS 1 Base board | substrate 2 Movable part formation board 3 Cover board | substrate 4 Electromagnet apparatus 5 Contact 5a 1st conductive layer 5b 2nd conductive layer 14 Fixed contact 21 Frame part 22 1st spring part 23 Movable part 24 Armature 26 2nd spring part 27 Movable contact 28 Contact holding part

Claims (5)

The contact point is composed of a nano-periodic laminated film in which the first conductive layer and the second conductive layer are alternately stacked, and the outermost layer is the first conductive layer, and the first conductive layer includes Au, Au alloy, Ag , Ag alloy, composite material of Au or Ag and dissimilar metal, composite material of Au or Ag and metal oxide, composite material of Au or Ag and metal nitride, composite material of Au or Ag and metal sulfide , Au or Ag and a metal boride, and the second conductive layer is made of W, Ru, Ir, Rh, IrO ₂ , TiB ₂ , TiC, ZrB _2. A contact formed by a second material selected from the group consisting of ZrC, NbC, and WC.   The Au alloy is an alloy of Au and at least one metal selected from the group of Ag, Ni, Cu, Pd, Pt, Co, and Zn. The Ag alloy includes Ag, Au, Au, Ni, 2. The contact according to claim 1, wherein the contact is an alloy with at least one metal selected from the group consisting of Cu and Pd.   The contact according to claim 1, wherein the first conductive layer and the second conductive layer are formed by a sputtering method.   A movable contact and a fixed contact on which the movable contact comes into contact with and away from each other are provided, and at least one of the movable contact and the fixed contact includes the contact according to any one of claims 1 to 3. And a switch.   A base substrate provided with a fixed contact on one surface side in the thickness direction, a cover substrate disposed opposite to the one surface side of the base substrate, and an electromagnet device housed in one of the base substrate and the cover substrate And a movable portion forming substrate disposed between the base substrate and the cover substrate, the movable portion forming substrate including a frame portion interposed between the base substrate and the cover substrate, and the frame A movable part that is arranged on the inner side of the frame part and is swingably supported by the frame part via a first spring part, an armature that is provided in the movable part and forms a magnetic circuit together with the electromagnet device, and a movable part A contact holding portion provided with a movable contact that is supported and movable toward and away from the fixed contact as the armature swings, and at least one of the movable contact and the fixed contact is a claim. Or MEMS relay, characterized in that it consists of contacts according to any one of claims 3.

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