JP5671213B2 - Method of joining conductors to metallic glass layer - Google Patents

Description

  The present invention relates to a method for joining a conductive wire to a metallic glass layer.

  In recent years, for example, pressure sensors, MEMS (micro electro mechanical systems) switches, electrostatic actuators, hydrogen detectors, capacitors, etc., have been used as metal glass applied devices using metal glass layers (metal glass thin films, metal glass substrates, etc.). (For example, Patent Documents 1 to 6), and a method for joining metal glass substrates is researched and developed in various places (for example, Patent Document 7).

Japanese Patent Laid-Open No. 2004-45048 JP 2008-155333 A JP 2009-10027 (paragraphs [0009]-[0025]) JP-A-2005-153110 (paragraphs [0009]-[0029]) JP 2008-8869 A Japanese Patent Laying-Open No. 2005-123235 (paragraphs [0016]-[0025]) JP 2008-214704 A

  By the way, since the metallic glass layer has conductivity, it is conceivable to electrically connect the conductive wire for wiring to the metallic glass layer. However, a technique for joining the conductive wire to the metallic glass has been developed. It wasn't. Here, the metallic glass has a strong surface oxide film, and is a material having a low-temperature joining property that is difficult to join at low temperature, and an experiment of soldering a conductive wire to the metallic glass was conducted. Elements that form stable oxides such as Zr, Ti, and Al were added, and it was impossible to obtain good wettability.

  This invention is made | formed in view of the said reason, The objective is to provide the joining method of the conducting wire to the metal glass which can join a conducting wire to the metallic glass layer stably.

The invention of claim 1 is a method of joining a conductive wire to a metallic glass layer for joining a conductive wire to a metallic glass layer, wherein the metallic wire is pressed against the joining surface of the metallic glass layer to give ultrasonic energy to the conductive wire. to so that to bond the glass layer and the conductor, using a bonding wire as a conductor, a metallic glass comprising bonding the metallic glass layer and the conductor to perform the ultrasonic wire bonding, the metal glass layer is a Zr or Ti as a component a layer, and wherein the Mochiiruko the Al-based bonding wire as bonding wire.

  According to the present invention, by applying ultrasonic energy to the conductive wire, the oxide on the bonding surface in the metallic glass layer is removed by ultrasonic vibration (depending on the material of the conductive wire, the oxide on the bonding surface of the conductive wire is also removed by ultrasonic vibration. In addition, direct bonding and the anchor effect of the conductive wire to the bonding surface of the metal glass layer (the function of improving the adhesion by increasing the mechanical fitting force) are promoted, so the conductive wire is stably bonded to the metal glass layer. can do.

Further, according to this invention, it is possible to reduce the bonding area required to ensure the desired bonding strength between the conductor in the metallic glass layer.

Further, according to this invention, the oxide bonding surface of the metallic glass layer is easily removed by ultrasonic vibration at room temperature, and a metallic glass layer and the conductor are joined more firmly. Furthermore, by direct bonding between the high affinity components of the Al-based bonding wire and the metallic glass layer, metal bonding by the formation of intermetallic compounds, and the reaction between the bonding bonding surface of the Al-based bonding wire and the metallic glass layer with the oxide of the metallic glass. Joining by the produced complex oxide is also performed.

  Moreover, according to this invention, since a conducting wire can be joined at normal temperature to a metal glass layer having a stable oxide film that is easily oxidized, the metal glass layer can be joined without crystallization.

The invention of claim 2 is a method for joining a conductive wire to a metallic glass layer for joining a conductive wire to a metallic glass layer, wherein the conductive wire is joined to a joining surface in the metallic glass layer by soldering, and a joining portion in the conducting wire The metallic glass layer and the conducting wire are joined by solder by applying ultrasonic energy to the solder surrounding the wire.

  According to this invention, by applying ultrasonic energy to the solder, the oxide on the bonding surface in the metal glass layer is removed by ultrasonic vibration, and the anchor effect of the solder on the bonding surface of the metal glass layer is promoted. Thus, the conductive wire can be stably bonded to the metal glass layer.

The invention of claim 3 is the invention of claim 1 or billed to claim 2, before bonding the metallic glass layer and the conductor, and removing the oxide bonding surface of the metallic glass layer.

  According to this invention, since the oxide on the bonding surface in the metal glass layer is removed before the bonding between the metal glass layer and the conductive wire, a good bonding between the metal glass layer and the conductive wire can be obtained, and The time for applying the sonic energy can be shortened.

The invention of claim 4 is the invention of claim 1 or billed to claim 2, before bonding the metallic glass layer and the conductor, forming a concavo-convex shape of the anchor effect promotes the bonding surface of the metallic glass layer Features.

  According to this invention, since the concave and convex shape for promoting the anchor effect is formed on the joining surface of the metallic glass layer before joining the metallic glass layer and the conductive wire, the anchor effect at the time of joining is promoted, and the metallic glass layer and It is possible to obtain a good bond with the conducting wire, shorten the time for applying ultrasonic energy, and reduce the ultrasonic power.

According to a fifth aspect of the present invention, in the first to fourth aspects of the invention, the metallic glass layer and the conductive wire are joined in a reducing atmosphere.

  According to this invention, formation of the surface oxide at the time of joining is suppressed, and favorable joining of the metallic glass layer and the conducting wire can be obtained.

The invention of claim 6 is a method of joining a conductive wire to a metallic glass layer for joining a conductive wire to a metallic glass layer, wherein an aluminum film is formed on a joining surface in the metallic glass layer, and then the surface of the aluminum film The metallic glass layer and the conductive wire are bonded by pressing a conductive wire made of an aluminum-based bonding wire, a gold bonding wire or a copper bonding wire to give ultrasonic energy to the conductive wire.

  According to the present invention, it is formed of a material having a high affinity with the metal glass layer (a material that easily forms an intermetallic compound or a material that easily reacts with an oxide of the metal glass) and can be joined to a conductive wire. After the aluminum film is formed on the bonding surface of the metal glass layer, a metal glass layer is formed by pressing a lead made of an aluminum-based bonding wire, a gold bonding wire or a copper bonding wire against the surface of the aluminum film and applying ultrasonic energy to the lead. Since the lead wire and the lead wire are joined, the lead wire can be stably joined to the metal glass layer.

In invention of Claim 1, 2, 6, there exists an effect that a conducting wire can be stably joined to a metallic glass layer.

It is explanatory drawing of the joining method of the conducting wire to the metallic glass layer of embodiment. It is a schematic sectional drawing which shows an example of the metallic glass application device in the same as the above. It is explanatory drawing of the other example of the joining method of the conducting wire to the metallic glass layer same as the above. It is explanatory drawing of another example of the joining method of the conducting wire to the metallic glass layer same as the above.

  In this embodiment, as an example of a metallic glass application device having a metallic glass layer, a capacitive transducer having the configuration shown in FIG. 2 will be described, and then a bonding method to the metallic glass layer will be described.

  The capacitive transducer having the configuration shown in FIG. 2 is a capacitive microphone that is formed using the metallic glass substrate 1 and is movable to one surface side (upper surface side in FIG. 2) of the metallic glass substrate 1. A transducer substrate A on which a diaphragm portion 11 also serving as an electrode 14 is formed; a fixed plate portion 20 made of a silicon nitride film disposed opposite to the transducer substrate A via a spacer 30 made of a rectangular frame-like insulating layer; A fixed electrode 24 formed on the movable plate 14 side of the fixed plate portion 20, and a fixed electrode portion formed of a laminate of the fixed plate portion 20 and the fixed electrode 24 is provided between the fixed electrode portion and the movable electrode 14. A plurality of acoustic holes (not shown) are provided through which the space and the external space on the opposite side of the fixed electrode portion communicate with each other. In the present embodiment, the metal glass substrate 1 constitutes a metal glass layer.

  In the above-described transducer substrate A, the planar shape of the diaphragm portion 11 is a rectangular shape (in this embodiment, a square shape), and the entire periphery is continuously and integrally connected to the frame portion 13 having a rectangular frame shape. The diaphragm portion 11 of the transducer substrate A is formed by providing a recess 5 on the other surface of the metal glass substrate 1.

  In the above-described capacitance type transducer, since the capacitor is formed by the movable electrode 14 and the fixed electrode 24 provided on the fixed plate portion 20, the movable electrode 14 and the fixed electrode are received by the diaphragm portion 11 receiving the sound pressure. The distance to 24 changes, and the capacitance of the capacitor changes. Therefore, a part of the frame portion 13 continuously integrated with the diaphragm portion 11 also serving as the movable electrode 14 is used as a pad portion, and between the pad portion and the pad 26 electrically connected to the fixed electrode 24 via the wiring 25. If a DC bias voltage is applied, a minute voltage change occurs between the pad portion and the pad 26 according to the pressure of the sound wave, so that the sound wave can be converted into an electric signal. Further, since the acoustic transducer is formed in the fixed electrode portion in the above-described capacitance type transducer, for example, when the diaphragm portion 11 is vibrated by the pressure of a sound wave, it is excessively caused by air as a medium of the space. Therefore, it is possible to obtain a flat frequency characteristic and a wide dynamic range over a wide frequency band.

Further, in the electrostatic capacitance type microphone described above, that has a diaphragm portion 11 is constituted by a portion of the metallic glass substrate 1.
In here, as a metallic glass which is the material of the metallic glass layer serving as a metal glass substrate 1, the metallic glass mainly composed of Cu (Cu ₆₀ Zr ₃₀ Ti ₁₀ or _{Cu 45 Zr 35 Al 15 Ag 5} ) a and Ni mainly Although metal glass (Ni ₆₀ Nb ₂₀ Ti ₁₀ Zr ₁₀ ) as a component is adopted, the present invention is not limited to this, and depending on the desired characteristics of the metal glass layer, for example, Zr, Ti, Fe, Ni, Pd, etc. You may employ | adopt the metal glass which has either of these as a main component.

  By the way, the above-mentioned capacitance type transducer is a conductor pattern electrically connected to the capacitance type transducer on one surface side of an insulating substrate 41 made of glass epoxy resin or the like, for example, as shown in FIG. It is mounted on the mounting substrate 40 on which 42 and 43 are formed.

  Here, the mounting substrate 40 has a sound wave introducing opening 45 formed in a portion corresponding to the recess 5 of the metallic glass substrate 1 of the capacitive transducer, and the capacitive transducer is a metallic glass substrate. 1 is bonded to the insulating substrate 41 via a bonding portion 70 made of a die bond material (for example, epoxy resin, silicone resin, etc.), and the pad portion made of the part of the frame portion 13 is bonded to a bonding wire. The other side of the mounting substrate 40 is connected to one conductor pattern 42 of the mounting substrate 40 through a conductive wire (first conductive wire) 2, and the pad 26 is connected to a second conductive wire made of a bonding wire (not shown). The conductor pattern 43 is electrically connected.

  Hereinafter, the joining method of the conducting wire 2 to the metallic glass substrate 1 for joining the conducting wire 2 to the metallic glass substrate 1 as the metallic glass layer will be described with reference to FIG.

  In the present embodiment, as shown in FIG. 1, the metallic glass substrate 1 is pressed against the bonding surface (the surface of the pad portion), and the ultrasonic energy is applied to the conductive wire 2 from the ultrasonic tool 3 to apply the metallic glass. The substrate 1 and the conductive wire 2 are joined.

Here, in this embodiment, since a bonding wire is used as the conducting wire 2 and the metallic glass substrate 1 and the conducting wire 2 are joined by ultrasonic wire bonding, the metallic glass substrate 1 can be connected to the conducting wire 2 in a desired manner. It is possible to reduce the bonding area (surface area of the portion regarded as the pad portion ) necessary for obtaining the bonding strength. In addition, an Al-based bonding wire is used as the bonding wire as the conducting wire 2, and the oxide (oxide film) on the bonding surface 1a of the metallic glass substrate 1 can be easily removed by ultrasonic vibration at room temperature, and the metallic glass. The board | substrate 1 and the conducting wire 2 are joined more firmly. In the present embodiment, the conductive wire 2 made of an Al-based bonding wire and the metallic glass substrate 1 are directly bonded to each other with high affinity components, metal bonding by generation of an intermetallic compound, or the conductive wire 2 made of an Al-based bonding wire and the metallic glass. Bonding with a complex oxide generated by reaction with an oxide of metal glass on the bonding surface of the substrate 1 is also performed. Moreover, since the conducting wire 2 can be joined to the metallic glass substrate 1 having a stable oxide film that is easily oxidized at room temperature, the metallic glass substrate 1 can be joined without being crystallized. Here, as the Al-based bonding wire, for example, a 1% Si—Al wire, a 1% Mg—Al wire, or the like having a wire diameter of 100 μm to 300 μm may be used. When an Al-based bonding wire is used in this way, a known wedge tool may be used as the ultrasonic tool 3 described above, and an ultrasonic vibration is applied to the ultrasonic tool 3 in the horizontal direction. Thus, ultrasonic energy may be given to the conductive wire 2. The bonding conditions in this case include, for example, an ultrasonic power of 2 to 4 W, an ultrasonic frequency of 20 to 100 kHz, a load of 1.96 to 3.92 N, and an ultrasonic application time of 100 to 500 ms. And the bonding temperature may be set to room temperature. Here, the bonding strength is evaluated by a wire pull test, and the conducting wire 2 breaks at about 2.5 to 5.0 N, but the joining interface between the conducting wire 2 and the metal glass substrate 1 does not break, and the bonding strength is strong. It was confirmed that In addition, since the Al-based bonding wire has a lower hardness as the purity of Al increases, an anchor effect is expected when using an Al bonding wire with a higher Al purity, and a 1% Si-Al bonding wire or When an Al-based bonding wire having a high hardness such as a 1% Mg—Al bonding wire is used, an effect of removing the oxide film on the bonding surface 1a of the composite oxide or metal glass substrate 1 is expected.

  In the bonding method of the conducting wire 2 to the metallic glass substrate 1 of the present embodiment described above, the oxide on the joining surface 1a in the metallic glass substrate 1 is removed (destructed) by ultrasonic vibration by applying ultrasonic energy to the conducting wire 2. (Depending on the material of the conductive wire 2, the oxide on the bonding surface of the conductive wire 2 is removed by ultrasonic vibration), and the direct bonding and the anchor effect of the conductive wire 2 to the bonding surface 1a of the metal glass substrate 1 are promoted. The conductive wire 2 can be stably bonded to the metal glass substrate 1 (can be firmly bonded). In addition, by using an Al-based bonding wire as the conducting wire 2, it is possible to achieve an extremely short time of about 100 to 500 ms without impairing the characteristics of the metallic glass substrate 1 below the glass transition temperature of the low-temperature bonding metallic glass substrate 1. High-strength bonding can be realized with the bonding time (here, the same as the ultrasonic wave application time).

  By the way, as a method for joining the conducting wire 2 to the metallic glass substrate 1 as the metallic glass layer, as shown in FIG. 3, the conducting wire 2 is joined to the joining surface 1a of the metallic glass substrate 1 by solder 80, 2 in the joining portion with the metallic glass substrate 1 (the end of the conducting wire 2 opposite to the end on the mounting substrate 40 side and overlapping the joining surface 1a of the metallic glass substrate 1 in the thickness direction of the metallic glass substrate 1). There is also a method in which the metallic glass substrate 1 and the conductive wire 2 are joined by the solder 80 by applying ultrasonic energy from the ultrasonic tool 3 to the solder 80 surrounding the portion 80). Here, as bonding conditions, for example, Sn—Zn—Sb solder is used as the solder 80, and the ultrasonic frequency may be set appropriately within a range of 20 to 100 kHz and a bonding temperature within a range of 200 to 300 ° C.

  According to the joining method in which the conductive wire 2 is joined to the joining surface 1a of the metallic glass substrate 1 by the solder 80, the ultrasonic energy is applied to the solder 80 so that the oxide on the joining surface 1a of the metallic glass substrate 1 is subjected to ultrasonic vibration. And the anchor effect of the solder 80 to the bonding surface 1a of the metal glass substrate 1 is promoted, so that the conductor 2 can be stably bonded to the metal glass substrate 1 (in this case, the conductor 2 is Since the solder 80 is bonded to the bonding surface 1a of the metallic glass substrate 1, the conductive wire 2 is bonded to the metallic glass substrate 1 through the solder 80).

  By the way, in the above-mentioned joining method, before joining the metallic glass substrate 1 which is a metallic glass layer and the conducting wire 2, the oxide (oxide film) on the joining surface 1a in the metallic glass substrate 1 is physically treated (for example, Ar or the like). If the metal glass substrate 1 and the conductive wire 2 are bonded together, the oxide on the bonding surface 1a in the metal glass substrate 1 is removed. In addition to being able to obtain good bonding between the metallic glass substrate 1 and the conductive wire 2, it is possible to shorten the time for applying ultrasonic energy and reduce the power of ultrasonic waves, and damage the capacitive transducer in the bonding process. It becomes possible to prevent more reliably. The physical treatment for removing the oxide on the bonding surface 1a is not limited to the plasma irradiation of Ar or the like, and any appropriate method may be adopted depending on the structure of the metallic glass application device, for example, grinding or polishing may be used. .

  Further, in the above-described joining method, before joining the metallic glass substrate 1 and the conductor 2, an uneven shape for promoting the anchor effect is formed on the joining surface 1 a of the metallic glass substrate 1 by a sputtering method or the like. Before the metal glass substrate 1 and the conductive wire 2 are joined, an uneven shape for promoting the anchor effect is formed on the joining surface 1a of the metal glass substrate 1, so that the anchor effect at the time of joining is promoted, and the metal glass substrate 1 and the conductive wire. 2 can be obtained, and it is possible to shorten the time for applying the ultrasonic energy, and to more reliably prevent the capacitive transducer from being damaged in the bonding process. In addition, the method of forming the uneven | corrugated shape for anchor effect promotion is not restricted to a sputtering method, What is necessary is just to employ | adopt suitably according to the structure of a metallic glass application device, etc. For example, sandblasting and grinding | polishing may be sufficient.

  Further, in the bonding method described above, when the metal glass substrate 1 and the conductor 2 are bonded in a reducing atmosphere (for example, a hydrogen atmosphere, a nitrogen atmosphere, a vacuum atmosphere, or a nitrogen blow state), surface oxidation during bonding is performed. The formation of objects (for example, the surface oxides of the metal glass substrate 1, the conductive wire 2, and the solder 80) is suppressed, and good bonding between the metal glass substrate 1 and the conductive wire 2 can be obtained.

  By the way, as a method for bonding the conducting wire 2 to the metal glass substrate 1 as the metal glass layer, as shown in FIG. 4, after forming an aluminum film 90 on the bonding surface 1a of the metal glass substrate 1 by, for example, sputtering. The metallic glass substrate 1 and the conducting wire 2 are joined by pressing the conducting wire 2 made of an aluminum-based bonding wire, gold bonding wire or copper bonding wire against the surface of the aluminum film 90 and applying ultrasonic energy to the conducting wire 2. Also good. The joining conditions in this case are the same as in the example of FIG. 1 described above. For example, the ultrasonic power is 2 to 4 W, the ultrasonic frequency is 20 to 100 kHz, the load is 1.96 to 3.92 N, and the ultrasonic wave The application time may be set as appropriate within a range of 100 to 500 ms, and the bonding temperature may be set to room temperature.

  According to this bonding method, a material having high affinity with the metal glass substrate 1 (a material that easily forms an intermetallic compound or a material that easily reacts with an oxide of metal glass) and the conductor 2 A bondable aluminum film (desirably, an Al—Si film which is an aluminum film to which Si is added or an Al—Cu film which is an aluminum film to which Cu is added) 90 is formed on the bonding surface 1 a of the metallic glass substrate 1. Then, the metallic glass substrate 1 and the conducting wire 2 are joined by pressing the conducting wire 2 made of an aluminum-based bonding wire, a gold bonding wire or a copper bonding wire against the surface of the aluminum film 90 and applying ultrasonic energy to the conducting wire 2. The conducting wire 2 can be stably bonded to the metallic glass substrate 1 at room temperature. Here, before forming the aluminum film on the bonding surface 1a of the metal glass substrate 1, an uneven shape for promoting the anchor effect may be formed on the bonding surface 1a of the metal glass substrate 1 by sputtering or the like.

  In the above-described embodiment, the metal glass substrate 1 constitutes the metal glass layer. However, the metal glass layer is appropriately constituted according to the structure of the metal glass application device, for example, a metal glass thin film. It may be constituted by. In addition, metallic glass application devices are not limited to capacitive transducers. For example, pressure sensors, MEMS switches, electrostatic actuators, hydrogen sensing elements, capacitors, resistors for thermal fuses (crystallized at a certain temperature or higher) It may be shabby).

1 Metal glass substrate (metal glass layer)
1a Bonding surface 2 Conductor 3 Ultrasonic tool 80 Solder 90 Aluminum film

Claims (6)

A method of bonding a conductive wire to a metallic glass layer, wherein the conductive glass is bonded to the metallic glass layer, and the metallic glass layer and the conductive wire are bonded by pressing the conductive wire against the bonding surface of the metallic glass layer and applying ultrasonic energy to the conductive wire. to be so that, using a bonding wire as a conductor, the junction between the metallic glass layer and the conductor to perform the ultrasonic wire bonding, a metal glass layer containing as a component a is Zr or Ti metallic glass layer, a bonding wire method of bonding wires of the Al-based bonding wire to the metallic glass layer characterized by the Mochiiruko. A method of bonding a conductive wire to a metallic glass layer, wherein the conductive wire is bonded to the bonding surface of the metallic glass layer by solder, and the solder surrounding the bonding portion of the conductive wire is super method for joining conductors and bonding child the metallic glass layer and the conductor by soldering to the feature and be Rukin genus glass layer by applying a wave energy. 3. The method for bonding a conductive wire to a metal glass layer according to claim 1 or 2 , wherein the oxide on the bonding surface of the metal glass layer is removed before bonding the metal glass layer and the conductive wire. Before bonding the metallic glass layer and the conductor, to claim 1 or claim 2 wherein the metallic glass layer you characterized that you form a concavo-convex shape of the anchor effect promotes the bonding surface of the metallic glass layer Wire joining method. Method of joining lead to the metallic glass layer according to any one of claims 1 to 4, characterized that you perform bonding between the metal glass layer and conductor in a reducing atmosphere. A method of bonding a conductive wire to a metallic glass layer, wherein the conductive wire is bonded to the metallic glass layer, wherein an aluminum film is formed on the bonding surface of the metallic glass layer, and then an aluminum-based bonding wire or gold method for joining conductors that you join the metallic glass layer and the conductor to the feature and be Rukin genus glass layer by applying ultrasonic energy to the wire pressing a wire made of the bonding wire or copper bonding wire.

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