JP4986540B2 - Surface acoustic wave device and manufacturing method thereof - Google Patents

Description

  The present invention relates to a surface acoustic wave device and a method for manufacturing the same. This surface acoustic wave device is particularly suitable for a wireless communication circuit such as a mobile communication device.

  In recent years, surface acoustic wave devices having surface acoustic wave resonators, surface acoustic wave filters, and the like have been used in a wide range of fields such as various wireless communication devices, in-vehicle devices, and medical devices using a microwave band. . And along with the miniaturization of these devices, the surface acoustic wave device is required to be further miniaturized. FIG. 9 is a schematic cross-sectional view of a conventional representative surface acoustic wave device 100.

  The surface acoustic wave device 100 includes a surface acoustic wave element S and a mounting substrate 120. The surface acoustic wave element S includes a piezoelectric substrate 110, comb-shaped electrode IDT (Inter Digital Transducer) electrodes 111 on the piezoelectric substrate 110, and input / output electrode pads 112 as wiring electrodes. On the other hand, the mounting substrate 120 includes an electrode pattern 121 connected to an external circuit such as a drive circuit, a resonance circuit, and a ground circuit. On this electrode pattern 121, a bump connector 130 made of a meltable metal material such as solder for connecting to the electrode pad 112 is formed.

  The surface acoustic wave device 100 is formed with an annular electrode portion 131 that is formed in an annular shape in a plan view of the surface acoustic wave device 100 in order to maintain the airtightness of the space surrounding the IDT electrode 111. The bump connection body 130 is formed using a vapor deposition method, a printing method, a transfer method, an electroless plating method, an electrolytic plating method, or the like.

  The annular electrode part 131 is formed by forming a metallizing film on the piezoelectric substrate 110 by vapor deposition or the like and then patterning it using a photolithography technique.

  The piezoelectric substrate 110 and the mounting substrate 120 are placed with the electrode pads 112 and the electrode patterns 121 formed at positions facing each other. Then, by melting the bump connection body 130 by the reflow melting method, the piezoelectric substrate 110 and the mounting substrate 120 are electrically and mechanically connected. In addition, the piezoelectric substrate 110 and the mounting substrate 120 are mechanically connected by an annular electrode portion 131.

  In this manner, the surface acoustic wave device 100 faces the functional surface provided with the IDT electrode 111 of the surface acoustic wave element S and the surface on which the electrode pattern 121 of the mounting substrate 120 is located, and is mounted and fixed face-down. The flip chip method is used (see, for example, Patent Document 1). FIG. 10 is a cross-sectional view of an electrode pad 112 included in a conventional surface acoustic wave device. As shown in FIG. 9, the surface acoustic wave device connects an interdigital electrode (IDT electrode 111 in FIG. 9) made of Al (aluminum) or an Al alloy, and the interdigital electrode and an external circuit (not shown). The electrode pad 112 is provided. The surface acoustic wave device is also face-down bonded by a bump connection body (bump connection body 130 in FIG. 9) formed on the electrode pad 112.

  The electrode pad 112 is formed on the surface of the base electrode 113 formed on the piezoelectric substrate 110, a Cr (chromium) layer 114 as an adhesion electrode layer formed on the upper surface of the base electrode 113, and the Cr layer 114. And an Au (gold) electrode layer 116 that is formed of a metal such as Au (gold) and forms the outermost portion of the electrode pad 112.

The base electrode 113 is made of Al or an Al alloy. The Cr layer 114 is formed so as to cover all or part of the surface of the base electrode 113. The Cr layer 114 is interposed between the base electrode 113 and the Ni layer 115 in order to increase the adhesion of the Ni layer 115. The Ni layer 115 is formed of a single layer of Ni material as a barrier metal. The barrier metal refers to a metal thin film sandwiched between electrode pads 112 in order to prevent the formation of other phases due to diffusion and reaction occurring between different metal films or semiconductors and metal films (for example, patents). Reference 2).
JP-A-4-293310 Japanese Patent Application Laid-Open No. 11-234082

  As in Patent Document 2, since the Ni layer 115 included in the wiring electrode (electrode pad) 112 is formed as a barrier metal, the film of the Ni layer 115 is formed relatively thick. Here, the Cr layer 114 and the Ni layer 115 sandwiched between the base electrode 113 and the Au electrode layer 116 are collectively referred to as an “intermediate layer 117”. Since the Ni layer 115 is formed relatively thick on the intermediate layer 117, a strong film stress may occur in the Ni layer 115. Then, the film stress is transmitted to the entire electrode pad 112 due to the film stress generated in the Ni layer 115, and the film is formed at the interface between the base electrode 113, the Cr layer 114, and the Ni layer 115 forming the wiring electrode 112. The stress cannot be absorbed, and the bonding strength between the layers decreases. In particular, since the bonding strength between the layers decreases, peeling easily occurs at the interface of the layer below the portion where the Ni layer 115 is formed. For this reason, sufficient electrical connection of the wiring electrode 112 is ensured. Thus, the reliability of the surface acoustic wave device 100 cannot be ensured.

  On the other hand, a structure similar to that of the wiring electrode 112 can be used for the annular electrode. In this case as well, the annular electrode is formed by the film stress generated in the Ni layer 115 included in the intermediate layer 117. There is a risk of peeling at the interface of each layer. For this reason, the annular electrode part 131 including the annular electrode cannot sufficiently secure the airtightness of the space in which the IDT electrode 111 is formed.

  Therefore, in order to eliminate peeling due to film stress generated in the Ni layer 115, the surface acoustic wave element S is heated when the electrode pad 112 or the annular electrode is formed, and the adhesion strength of each layer forming the electrode pad 112 is increased. Can be considered. However, it is not preferable to heat the surface acoustic wave element S because the electrode formed on the piezoelectric substrate 110 may be destroyed due to the pyroelectric effect of the piezoelectric substrate 110.

  Further, when the film stress of the Ni layer 115 of the annular electrode portion 131 is increased, the film stress is also transmitted to the piezoelectric substrate 110, and as a result, the piezoelectric substrate 110 is warped. This causes many problems in the manufacturing process of the surface acoustic wave device such as pattern accuracy in stepper exposure used in photolithography, conveyance of the piezoelectric substrate 110, and vacuum suction on the stage. In addition, when the diameter of the piezoelectric substrate 110 is increased, the warp due to the film stress generated in the Ni layer 115 is enlarged on the piezoelectric substrate 110. Therefore, the piezoelectric substrate 110 is cracked particularly during vacuum suction. May occur.

  Incidentally, in the process of forming the intermediate layer 117 on the base electrode 113 using the lift-off method and forming the electrode pad 112, first, as shown in FIG. 11, the intermediate layer 117 and the Au electrode layer 116 are formed. In addition to the region, a photoresist film 119 having an inverse taper and an overhang shape is formed. Next, while masking with the photoresist film 119, the Cr layer 114, the Ni layer 115, and the Au electrode layer 116 are sequentially laminated to form the electrode pad 112.

  At this time, each layer (114, 115, 116) forming the electrode pad 112 is laminated on the base electrode 113, and at the same time, each layer (134, 135, 136) is laminated on the photoresist film 119 in order. Therefore, the film stress generated in the Ni layer 135 formed on the photoresist film 119 is transmitted to the photoresist film 119. Then, the photoresist film 119 is warped, and as a result, the end portion of the resist opening is lifted and spreads beyond the design area. As a result, the material for forming the intermediate layer 117 adheres to a portion other than the design area of the base electrode 113, and burrs remain around the base electrode 113 made of Al or Al alloy. If this burr adheres in an area larger than the designed area, there is a possibility that the IDT electrode 111 is short-circuited.

  In addition, since the burrs are extremely thin, the burrs have low adhesion to the substrate and the electrodes and are easily peeled off. As a result, the burrs that have been peeled off are easily short-circuited with the surrounding electrodes, and as a result, the characteristic failure of the surface acoustic wave device occurs. Therefore, in order to reduce the film stress generated in the Ni layer 115 (135) as described above, the Ni layer 115 (135) may be thin.

  However, when the Ni layer 115 (135) is made extremely thin, the Ni layer 115 does not function as a barrier metal that is the original purpose. The present invention has been made based on such a background, and has a coupling electrode including an electrode layer that sufficiently functions as a barrier metal against a meltable metal material such as solder, and the electrode. An object of the present invention is to provide a surface acoustic wave device that can relieve the film stress generated in the process and is excellent in airtightness and reliability and a method for manufacturing the same.

  In order to solve the above problems, a surface acoustic wave device of the present invention is a surface acoustic wave device in which a surface acoustic wave element is mounted on a mounting substrate by a wireless bonding method, and the surface acoustic wave element is a piezoelectric substrate. An excitation electrode formed on the main surface and a coupling electrode formed on the main surface of the piezoelectric substrate and connected to the electrode on the mounting substrate, the coupling electrode being the piezoelectric substrate A base electrode formed using a metal material mainly composed of Al, and an intermediate layer formed on the base electrode, the intermediate layer including an adhesion electrode layer and a barrier metal electrode The barrier metal electrode layer includes at least one impurity-containing layer.

  With this configuration, the surface acoustic wave element can be mounted on the mounting substrate using a coupling electrode including an electrode layer that sufficiently functions as a barrier metal with respect to a meltable metal material such as solder. An electrode that functions satisfactorily as a barrier metal for a meltable metal material such as solder, by forming the barrier metal electrode layer included in the coupling electrode as a laminate including at least one impurity-containing layer. The film stress of the barrier metal electrode layer can be relaxed while having the coupling electrode including the layer. Thereby, since the electrode for peeling does not generate | occur | produce and it can have the electrode for a coupling | bonding with which a characteristic defect does not arise, the surface acoustic wave apparatus excellent in airtightness and excellent in reliability can be provided.

  The coupling electrode may be an annular electrode formed at a position surrounding the outer periphery of the excitation electrode. The coupling electrode may be a wiring electrode connected to the excitation electrode.

  The barrier metal electrode layer preferably contains at least one material of Ni and Cu. Thereby, since diffusion of meltable metals such as solder can be suppressed satisfactorily, formation of brittle intermetallic compounds and peeling between metal layers are hardly caused, and the reliability of the surface acoustic wave device can be improved.

  Moreover, it is preferable that the said impurity content layer contains at least 1 material of carbon, sulfur, and oxygen as an impurity in the material which forms the said barrier metal electrode layer. Thereby, the impurity-containing layer can reduce the film stress generated in the barrier metal electrode layer. The barrier metal electrode layer preferably has a thickness in the range of 0.5 μm to 1.5 μm. Thereby, the thickness of the barrier metal layer is not inferior in the role as a barrier metal to the connection metal such as solder as in the case where the film thickness is smaller than 0.5 μm, and as in the case where it is thicker than 1.5 μm, The film stress is not significantly increased.

  Moreover, it is preferable that the said contact | adherence electrode layer contains the material of at least 1 among Cr, Ti, V, and Pt. Thereby, the adhesiveness of a base electrode and a barrier metal electrode layer can be improved.

  In the method of manufacturing the surface acoustic wave device according to the present invention, the surface acoustic wave device is manufactured by forming the excitation electrode and the coupling electrode to be connected to the electrode on the mounting substrate on the main surface of the piezoelectric substrate. A surface acoustic wave device manufacturing method for mounting the surface acoustic wave element on the mounting substrate by a wireless bonding method, wherein the coupling electrode has Al as a main component on a main surface of the piezoelectric substrate. A first step of forming a base electrode of the coupling electrode using a metal material, a second step of forming a close-contact electrode layer on the base electrode, and a barrier metal electrode on the close-contact electrode layer It is manufactured by the 3rd process of forming the laminated body of a layer and an impurity content layer, It is characterized by the above-mentioned.

  With this configuration, it is possible to form a coupling electrode including an electrode layer sufficiently functioning as a barrier metal with respect to a meltable metal material such as solder, and using the coupling electrode, a surface acoustic wave element can be formed. A surface acoustic wave device can be manufactured by mounting on a mounting substrate. An electrode that functions satisfactorily as a barrier metal for a meltable metal material such as solder, by forming the barrier metal electrode layer included in the coupling electrode as a laminate including at least one impurity-containing layer. The film stress of the barrier metal electrode layer can be relaxed while having the coupling electrode including the layer. As a result, it is possible to form a coupling electrode that does not cause electrode peeling and does not cause poor characteristics. As a result, a surface acoustic wave device that is excellent in airtightness and reliability can be manufactured.

  The barrier including the piezoelectric substrate before forming the base electrode, the base electrode before forming the contact electrode layer, the contact electrode layer before forming the barrier metal electrode layer, and the impurity-containing layer. It is preferable that at least one surface of the metal electrode layer is roughened by performing bombardment treatment with at least one of argon ions, oxygen ions, and nitrogen ions. Thereby, the curvature by the film stress which arises in each layer can further be suppressed by roughening the interface of each layer which forms the electrode for coupling.

  The coupling electrode may be an annular electrode formed at a position surrounding the outer periphery of the excitation electrode. The coupling electrode may be a wiring electrode connected to the excitation electrode.

  The barrier metal electrode layer preferably contains at least one material of Ni and Cu. Thereby, since diffusion of meltable metals such as solder can be suppressed satisfactorily, formation of brittle intermetallic compounds and peeling between metal layers are hardly caused, and the reliability of the surface acoustic wave device can be improved.

  Moreover, it is preferable that the said impurity content layer contains at least 1 material of carbon, sulfur, and oxygen as an impurity in the material which forms the said barrier metal electrode layer. Thereby, the impurity-containing layer can reduce the film stress generated in the barrier metal electrode layer.

  The barrier metal electrode layer preferably has a thickness in the range of 0.5 μm to 1.5 μm. Thereby, the thickness of the barrier metal layer is not inferior in the role as a barrier metal to the connection metal such as solder as in the case where the film thickness is smaller than 0.5 μm, and as in the case where it is thicker than 1.5 μm, The film stress is not significantly increased.

  Moreover, it is preferable that the said contact | adherence electrode layer contains the material of at least 1 among Cr, Ti, V, and Pt. Thereby, the adhesiveness of a base electrode and a barrier metal electrode layer can be improved.

  A communication device according to the present invention includes a mixer including a mixer that superimposes a transmission signal on a carrier wave signal to form an antenna transmission signal, and a surface acoustic wave device according to any one of claims 1 to 7 that attenuates an unnecessary signal of the antenna transmission signal. The transmission circuit includes a path filter and a power amplifier that amplifies the antenna transmission signal and outputs the amplified antenna transmission signal to an antenna through a duplexer. The communication device of the present invention is a low-noise amplifier that amplifies an antenna reception signal received by an antenna and passed through a duplexer, and an elastic signal according to any one of claims 1 to 7 that attenuates an unnecessary signal of the amplified antenna reception signal. And a reception circuit including a band-pass filter including a surface wave device and a mixer for separating a reception signal from a carrier wave signal of the antenna reception signal.

  With the above configuration, even if the communication device is dropped, etc., since the surface acoustic wave device having excellent airtightness and excellent reliability is used, the surface acoustic wave device is not damaged or deteriorated. As a result, the communication device is highly durable and reliable.

  The device of the present invention is a piezoelectric substrate, a first electrode for generating a surface acoustic wave formed on a main surface of the piezoelectric substrate, a mounting substrate, and the piezoelectric substrate and the mounting substrate. A second electrode made of a metal having Al as a main component and formed on the main surface of the piezoelectric substrate; a contact electrode layer formed on the base electrode; and the contact electrode layer And a second electrode including a barrier metal electrode layer including a first metal layer and a second metal layer containing more impurities than the first metal layer. .

  With this configuration, a first electrode that generates surface acoustic waves is formed using a second electrode that includes a barrier metal electrode layer that functions sufficiently as a barrier metal with respect to a meltable metal material such as solder. The piezoelectric substrate can be mounted on the mounting substrate. The barrier metal electrode layer included in the second electrode is formed of a laminate including the first metal layer and the second metal layer containing a larger amount of impurities than the first metal layer. On the other hand, the film stress of the barrier metal electrode layer can be alleviated while having the second electrode including the barrier metal electrode layer that functions sufficiently as a barrier metal. Thereby, since it can have the 2nd electrode which electrode peeling does not generate | occur | produce and a characteristic defect does not produce, the device excellent in airtightness and excellent in reliability can be provided.

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

  FIG. 1 is a plan view of a surface acoustic wave element according to an embodiment of the present invention. The surface acoustic wave element S 1 connects the piezoelectric substrate 1, the IDT electrode 8 having comb-like electrodes, the wiring electrode 12 for inputting / outputting electric signals to / from the IDT electrode 8, and the IDT electrode 8 and the wiring electrode 12. And a ring electrode 11 for hermetically sealing the periphery of the IDT electrode 8. In the piezoelectric substrate 1, a protective film 10 is formed on the IDT electrode 8 and the lead-out wiring 9 on the side (main surface) where the IDT electrode 8 is formed.

The piezoelectric substrate 1 is, for example, a 36 ° Y cut-X propagation LiTaO ₃ single crystal, a 64 ° Y cut-X propagation LiNbO ₃ single crystal, or a 45 ° X cut-Z propagation LiB ₄ O ₇ single crystal. It is formed using the material which has the following piezoelectricity. Thereby, the piezoelectric substrate 1 can increase the electromechanical coupling coefficient and reduce the group delay time temperature coefficient.

  The thickness of the piezoelectric substrate 1 is preferably about 0.3 to 0.5 mm. Therefore, the piezoelectric substrate 1 does not become brittle as when the thickness is less than 0.3 mm, and conversely, when the thickness is greater than 0.5 mm. The material cost does not increase.

  The IDT electrode 8 is an excitation electrode for generating surface acoustic waves. The IDT electrodes 8 are formed in a comb-teeth shape that meshes with each other. The IDT electrode 8 preferably has a logarithm of 50 to 200, an electrode finger width of 0.1 to 10 μm, an electrode finger interval of 0.1 to 10 μm, and an electrode finger crossing width of 10. ˜80 μm. The IDT electrode 8 has a thickness of 0.2 to 0.4 μm in order to obtain the desired characteristics as a surface acoustic wave resonator or a surface acoustic wave filter. The IDT electrode 8 may have a structure in which reflectors are provided at both ends of the propagation path of the surface acoustic wave in order to reflect the generated surface acoustic wave and efficiently resonate.

  The IDT electrode 8 is formed using an Al—Cu-based Al alloy metal material. A metal other than Cu added to the Al—Cu-based Al alloy may be a metal such as Ti, Ta, W, or Mo. The IDT electrode 8 may be formed by laminating Al alloys containing metals such as Ti, Ta, W, and Mo.

  The IDT electrode 8 can also be applied to a slit-type reflector in which a plurality of electrode fingers are arranged in parallel. In addition, although the IDT electrode 8 showed the example which comprises the surface acoustic wave filter in which the double mode surface acoustic wave resonator filter and the ladder type surface acoustic wave filter were mixed like FIG. It may constitute a wave resonator filter or a ladder type surface acoustic wave filter.

  The IDT electrode 8 is connected to a plurality of wiring electrodes 12 by a plurality of lead wires 9. The IDT electrode 8 and the lead wiring 9 are covered with an insulating protective film 10.

  The wiring electrode 12 is made of a conductive metal material. The wiring electrode 12 is joined to a wiring connection electrode (not shown) on a mounting substrate (not shown) formed at a position facing the wiring electrode 12 by a meltable metal material such as solder. The IDT electrode 8 in the surface acoustic wave element S1 is electrically and mechanically connected to an external wiring (not shown) connected to the mounting substrate.

  The annular electrode 11 is formed at a position surrounding the IDT electrode 8. Then, the annular electrode 11 is joined to an annular connection electrode (not shown) on the mounting substrate formed at a position facing the annular electrode 11 by a meltable metal material such as solder. The wave element S1 and the mounting substrate are mechanically connected.

  The IDT electrode 8 and the lead-out wiring 9 are formed of an Al alloy containing Al as a main component by using a thin film forming method such as a sputtering method, a vapor deposition method or a CVD method (Chemical Vapor Deposition). . Then, patterning is performed using a photolithography method to form a predetermined shape.

The protective film 10 is formed of an insulator such as a SiO ₂ film, a SiN film, or a Si film by using a thin film forming method such as a CVD method or an evaporation method.

  Thus, the surface acoustic wave element S1 includes at least a pair of the IDT electrodes 8 as described above. The surface acoustic wave element S1 can include a plurality of pairs of IDT electrodes 8 connected by a connection method such as series connection or parallel connection in order to obtain desired characteristics.

  FIG. 2 is an enlarged cross-sectional view taken along line A-A ′ of the annular electrode 11 in FIG. 1. FIG. 3 is an enlarged sectional view taken along line B-B ′ of the wiring electrode 12 in FIG. 1.

  The annular electrode 11 includes a base electrode 2 made of an Al alloy, a contact electrode layer 3 formed on the base electrode 2, a barrier metal electrode layer 4 stacked on the contact electrode layer 3, and a ring And an Au electrode layer 6 forming the outermost layer of the electrode 11. In the example of FIG. 2, the barrier metal electrode layer 4 is a laminate of five layers. There are three base material layers 4A made of only the base material of the barrier metal electrode layer 4, and two impurity-containing layers 4B are stacked so as to be sandwiched between them. For example, the impurity-containing layer 4B is formed by adding impurities to the base material of the barrier metal electrode layer 4. Here, the adhesion electrode layer 3 and the barrier metal electrode layer 4 sandwiched between the base electrode 2 and the Au electrode layer 6 are collectively referred to as an “intermediate layer 7”.

  The base electrode 2 is formed of an Al alloy containing Al as a main component by using a thin film forming method such as a sputtering method, a vapor deposition method, or a CVD method. The thickness of the base electrode 2 is 0.2 μm to 0.4 μm. Then, patterning is performed by a photolithography method to form a predetermined shape.

  The adhesion electrode layer 3 is made of a material containing Cr, Ti, V, Pt or the like in order to improve adhesion with the base electrode 2. In particular, when the adhesion electrode layer 3 is formed using Cr or Ti among the materials listed above, adhesion with the base electrode 2 formed of an Al alloy can be improved. Moreover, the thickness of the contact electrode layer 3 is 0.01 μm to 0.03 μm.

  The barrier metal electrode layer 4 is made of a material containing Ni or Cu in order to suppress the diffusion of solder. Thereby, since diffusion of solder can be satisfactorily suppressed, formation of brittle intermetallic compounds and peeling between metal layers are hardly caused, and the reliability of the surface acoustic wave device can be improved. In particular, among the materials mentioned above, when the barrier metal electrode layer 4 is formed using Ni, the diffusion rate of the solder can be reduced as compared with the case where Cu is used, and the solder is grounded during reflow. It is possible to further suppress solder erosion that diffuses to the electrode 2.

  The impurity-containing layer 4B laminated on the barrier metal electrode layer 4 uses Ni as a main material in order to reduce film stress generated in the barrier metal electrode layer 4, and carbon, sulfur, Substances such as oxygen are added. In particular, when carbon or oxygen is used as the impurity contained in the impurity-containing layer 4B, the impurity-containing layer 4B can reduce the film stress generated in the intermediate layer 7. In particular, when carbon is used as the impurity, the electrical resistance of the annular electrode 11 including the impurity-containing layer 4B is reduced, so that the impurity-containing layer 4B can improve the insertion loss of the surface acoustic wave element S1 satisfactorily. .

  When carbon is used as an impurity, the impurity concentration is about 3.0 to 3.5% by weight, and sulfur and oxygen are about the same as or lower than carbon, respectively. The impurity concentration when carbon, sulfur and oxygen impurities are naturally mixed is on the order of ppm, which is an extremely small value.

  The overall thickness of the barrier metal electrode layer 4 including the impurity-containing layer 4B is preferably formed in the range of 0.5 μm to 1.5 μm. At this time, as the thickness of the barrier metal layer 4 is thinner than 0.5 μm, the role as a barrier metal for the connection metal such as solder is not inferior, and when the thickness is larger than 1.5 μm. Further, the film stress is not significantly increased.

  Further, the barrier metal electrode layer 4 including the impurity-containing layer 4B may not have a configuration in which the interfaces can be clearly distinguished as shown in FIG. 2, and the impurity concentration gradually increases in the thickness direction of the barrier metal electrode layer 4. It may be configured to change. In other words, the impurity concentration may have a gradient in the thickness direction of the barrier metal electrode layer 4. Such a configuration can be formed, for example, by gradually changing the impurity concentration in the atmosphere in the film forming apparatus when the barrier metal electrode layer 4 is formed by a thin film forming method such as sputtering or vapor deposition. In addition, it can be formed using a target having a gradient in impurity concentration when formed by a sputtering method.

  In the annular electrode 11, the adhesion electrode layer 3, the barrier metal electrode layer 4, and the Au electrode layer 6 are sequentially formed on the base electrode 2 by using a thin film forming method such as a sputtering method or a vapor deposition method. Further, in order to obtain a predetermined shape of the annular electrode 11, a lift-off method is used. The formation process of the annular electrode 11 (coupling electrode) using this lift-off method will be described later.

  Further, as shown in FIG. 13, a barrier metal electrode layer 4 comprising a combination of only one base material layer 4A and only one impurity-containing layer 4B between the contact electrode layer 3 and the Au electrode layer 6. Even when the film is formed, the film stress generated in the intermediate layer 7 can be sufficiently reduced.

  The wiring electrode 12 may be formed by sequentially laminating the intermediate layer 7 and the Au electrode layer 6 on the base electrode 2 as in the case of the annular electrode 11 (see FIG. 3). Thereby, the wiring electrode 12 and the annular electrode 11 can be formed in the same process.

  FIG. 4 is a cross-sectional view of the surface acoustic wave device 90 in which the surface acoustic wave element S1 is mounted on the mounting substrate 60.

  A mounting substrate 60 included in the surface acoustic wave device 90 includes a base 61, an annular connection electrode 66, and a wiring connection electrode 62. An annular sealing material 65 for directly joining the annular electrode 11 is formed on the annular connection electrode 66, and a connection body for joining the wiring electrode 12 on the wiring connection electrode 62. 63 is formed. The annular electrode 11 as a coupling electrode is directly connected to the annular connection electrode 66 via a connection member (annular sealing material 65) such as solder or a conductor bump. That is, the annular electrode 11 is connected to the annular connection electrode 66 by a flip chip method or the like that does not use a wire such as a bonding wire.

  The base 61 may be formed, for example, by laminating a ceramic substrate and a frame-shaped ceramic substrate, or may be formed as a single ceramic substrate.

  The wiring connection electrode 62 and the annular connection electrode 66 are formed on the base 61 by electrolytic plating or electroless plating.

  Here, the connection body 63 has been described as being formed on the wiring connection electrode 62, but may be formed on the wiring electrode 12.

  The annular sealing material 65 formed on the annular connection electrode 66 and the connection body 63 formed on the wiring connection electrode 62 are made of solder paste, Au—Sn paste, or the like using a printing method such as screen printing. A metal material is formed. The annular sealing material 65 and the connection body 63 can also be simultaneously formed by applying the metal material using a dispenser method.

  Although the case where the annular sealing material 65 is formed on the annular connection electrode 66 is shown here, it may be formed on the annular electrode 11.

  The connection body 63 formed on the wiring connection electrode 62 is made of, for example, an anisotropic conductive resin in which a conductive filler such as a silver filler is mixed into an epoxy resin using a photolithography method, a printing method, or a dispenser method. It is formed by coating. In order to increase the viscosity of the epoxy resin used as the material of the connection body 63 so that the resin does not spread more than necessary, a thixotropic agent may be added as an additive, or the viscosity may be adjusted by the amount of filler. . The connection body 63 preferably has a reduced impurity ion concentration as much as possible so that electrode corrosion of the surface acoustic wave element S1 does not occur. The connection body 63 may also be formed by applying an anisotropic conductive resin using a photolithography method.

  In addition, the device of the present invention includes a piezoelectric substrate 1, a first electrode (corresponding to the IDT electrode 8 in FIG. 1) formed on the main surface of the piezoelectric substrate 1, and a mounting substrate. A second electrode (corresponding to the annular electrode 11 (coupling electrode) in FIG. 1) for coupling the piezoelectric substrate 1 and the mounting substrate, which is made of a metal mainly composed of Al and is the main electrode of the piezoelectric substrate 1 The base electrode 2 formed on the surface, the contact electrode layer 3 formed on the base electrode 2, and the first metal layer (base material of the barrier metal electrode layer 4 in FIG. 2) formed on the contact electrode layer 3 And a second electrode including a barrier metal electrode layer 4 including a second metal layer (corresponding to the impurity-containing layer 4B in FIG. 2) containing more impurities than the first metal layer. It is the structure provided with. Even in this configuration, a device having the same effects as the surface acoustic wave device shown in FIGS. 1 to 5 can be obtained.

  The first electrode that generates the surface acoustic wave may be an electrode that generates the surface acoustic wave, and is not limited to the IDT electrode 8, but, for example, one or more IDT electrodes 8, or one or more IDT electrode 8 and reflector electrodes formed at both ends thereof. The second electrode for coupling the piezoelectric substrate 1 and the mounting substrate is not limited to the annular electrode 11 (coupling electrode), and may be one or more pad-shaped electrodes.

  The device of the present invention is not limited to use as a surface acoustic wave device built in a communication device such as a mobile phone, but can be used as various devices utilizing surface acoustic waves. For example, an oscillation device, a frequency filter, etc. The present invention can be applied to devices, optical waveguide devices, light modulation devices, microelectromechanical system (MEMS) devices, and the like.

  The surface acoustic wave device 90 is manufactured by the following procedure.

  First, the surface acoustic wave element S1 is placed and fixed on the mounting substrate 60 as a face-down configuration in which the main surface side on which the IDT electrode 8 is formed faces the upper surface of the base 61.

  The wiring electrode 12 is connected to a wiring connection electrode 62 formed at a position facing the wiring electrode 12 via a connection body 63. The annular electrode 11 is connected to an annular connection electrode 66 formed at a position facing the annular electrode 11 via an annular sealing material 65. The surface acoustic wave element S1 is placed in a reflow furnace together with the mounting substrate 60 on which the surface acoustic wave element S1 is placed. The connection body 63 and the annular sealing material 65 are reflow-melted and then taken out from the reflow furnace and cooled to room temperature and solidified. A wiring electrode portion 92 is formed from the wiring electrode 12, the wiring connection electrode 62, and the connection body 63, and an annular electrode portion 91 is formed from the annular electrode 11, the annular connection electrode 66, and the annular sealing material 65. Thereby, the surface acoustic wave element S1 and the mounting substrate 60 are electrically and mechanically connected.

  By the way, the annular electrode portion 91 forms a vibration space 67 at a position surrounding the IDT electrode 8 by the main surface of the surface acoustic wave element S <b> 1 and the mounting surface of the mounting substrate 60. The vibration space 67 is hermetically sealed. The vibration space 67 is preferably sealed with low-humidity air in order to suppress deterioration due to oxidation or the like of the IDT electrode 8. Further, in order to further suppress deterioration due to oxidation or the like, an inert gas such as nitrogen gas or argon gas may be enclosed and sealed instead of the air.

  Next, a resin 64 is applied to the other main surface and the peripheral surface of the surface acoustic wave element S1 by a potting method, a printing method, or the like, and the resin 64 is heated and cured. Then, the surface acoustic wave device 90 is completed by dicing at the separation position between the surface acoustic wave elements S1.

  In the surface acoustic wave device 90, since the annular electrode portion 91 and the resin 64 surround the outer peripheral portion of the vibration space 67, airtightness and moisture resistance can be sufficiently ensured, and the reliability is excellent.

  Further, since at least one impurity-containing layer 4B is interposed inside the barrier metal electrode layer 4 used as the intermediate layer 7 of the annular electrode 11, the barrier metal electrode layer 4 relieves the film stress generated there. can do. Thereby, the annular electrode 11 is less likely to cause electrode peeling due to film stress, and can sufficiently secure the airtightness of the vibration space 67.

  Furthermore, since the surface acoustic wave device 90 is unlikely to be warped in each layer forming the annular electrode portion 91 due to film stress, the surface acoustic wave device 90 is less likely to warp. It can be produced accurately. Thereby, since a more detailed design can be performed, the surface acoustic wave device 90 can have high reliability while being thinned and miniaturized.

  Below, the manufacturing method of the annular electrode 11 and the wiring electrode 12 is demonstrated. From here, the annular electrode 11 and the wiring electrode 12 will be described together as a coupling electrode E.

  FIG. 5 is an enlarged cross-sectional view for explaining a method for manufacturing the coupling electrode E. FIG. In this embodiment, the interface of each layer forming the coupling electrode E is roughened, so that the film stress generated in each layer can be further absorbed. Here, the manufacturing method of the coupling electrode E will be described including the process of roughening the surface of the layer.

  The coupling electrode E (annular electrode 11 and wiring electrode 12) includes a base electrode 2 made of an Al alloy, an intermediate layer 7 including a close contact electrode layer 3 and a barrier metal electrode layer 4 formed on the base electrode 2, and a wiring. And an Au electrode layer 6 formed on the outermost layer of the electrode 12. In addition, one or more impurity-containing layers 4B are stacked on the barrier metal electrode layer 4 between the base material layer 4A of the barrier metal electrode layer and the base material layer 4A of the barrier metal electrode layer (this implementation). In the form, 2 layers in total).

  First, the base electrode 2 is formed on the piezoelectric substrate 1 by coating a metal material such as an Al alloy containing Al as a main component by using a thin film forming method such as sputtering, vapor deposition, or CVD. Then, patterning is performed by a photolithography method to form a predetermined shape.

  Next, the intermediate layer 7 for forming the adhesion electrode layer 3 and the barrier metal electrode layer 4 and the Au electrode layer 6 at the uppermost part thereof are formed in this order by using a thin film forming method such as a sputtering method or a vapor deposition method. .

  When the barrier metal electrode layer 4 is formed, sputtering is performed while switching to a Ni target material having a high concentration of carbon or sulfur during the sputtering film formation, whereby the barrier metal electrode layer 4 formed at that time has a concentration of carbon or sulfur. High impurity content layer 4B is formed. The impurity concentration of the target material is about 3.0 to 3.5% by weight for carbon, and sulfur and oxygen are about the same.

  As a method of forming the barrier metal electrode layer 4 including the impurity-containing layer 4B, a method of mixing carbon or sulfur as an impurity doping gas in an inert gas such as Ar used as a sputtering gas, in addition to the above-described method. It may be used.

  The barrier metal electrode layer 4 including the impurity-containing layer 4B can also be formed by providing a sputtering stop period (interval) when the barrier metal electrode layer 4 is formed by a sputtering method. That is, after forming the base material layer 4A of the first barrier metal electrode layer, the sputtering is temporarily stopped and then restarted. As a result, the base material layer 4A of the first barrier metal electrode layer contains the impurities contained in the target as they are, and therefore contains impurities at a low concentration similar to the concentration of the impurities in the target. On the other hand, the base material layer 4A of the second barrier metal electrode layer formed by restarting sputtering is formed by taking in impurities in the atmosphere at the time of restarting. A high-concentration impurity-containing layer 4B added with the concentration is formed first, and then a base material layer 4A containing a low-concentration impurity comparable to the target impurity concentration is formed. As a result, the impurity-containing layer 4B is formed between the base material layer 4A of the first barrier metal electrode layer and the base material layer 4A of the second barrier metal electrode layer. When the impurity-containing layer 4B is formed by a sputtering method provided with such a stop period, a gradient is easily formed in the impurity concentration.

  Although the detailed action mechanism of the incorporation of impurities in the atmosphere at the time of resuming sputtering as described above is not clear, it has been confirmed by experiments of the present inventors that the impurity-containing layer 4B is formed at the time of resuming sputtering. ing.

  By the way, before each layer of the coupling electrode E is formed, there is a method of cleaning the surface by bombarding the interface of at least one layer with at least one kind of ion of argon ion, oxygen ion and nitrogen ion. Used. Thereby, the surface of the layer bombarded in the coupling electrode E is roughened (in the figure, the surface of all layers is bombarded). In particular, since the interface of each layer forming the coupling electrode E is roughened, warping due to film stress generated in each layer can be further suppressed.

  Below, the process at the time of manufacturing the coupling electrode E on a surface acoustic wave element by the lift-off method is demonstrated.

  FIG. 6 is an enlarged cross-sectional view when the coupling electrode E is formed by the lift-off method. In the coupling electrode E, as described above, the intermediate layer 7 and the Au electrode layer 6 are sequentially formed on the base electrode 2.

  First, on the piezoelectric substrate 1, a photoresist film 22 having a reverse taper and an overhang shape is formed in addition to the region where the intermediate layer 7 is formed. Next, the adhesion electrode layer 3, the barrier metal electrode layer 4, and the Au electrode layer 6 are sequentially laminated while masking with the photoresist film 22, thereby forming the coupling electrode E. At this time, the Cr layer 23, the Ni layer 24, and the Au layer 25 are laminated on the photoresist film 22 at the same time when the coupling electrode E is formed. Similar to the barrier metal electrode layer 4, the Ni layer 24 includes an impurity-containing layer. Thereby, in the lift-off process at the time of forming the coupling electrode E, the film stress of the Ni layer 24 is reduced and the opening formed by the photoresist film 22 is less likely to be lifted. Therefore, when the coupling electrode E is formed, burrs are hardly generated, and the adhesion electrode layer 3, the barrier metal electrode layer 4, and the Au electrode layer 6 can be formed at almost the designed positions. By using the manufacturing method of the electrode E, the occurrence of short circuit defects due to burrs can be reduced, and as a result, the yield rate can be improved.

  Here, the coupling electrode E is formed using a lift-off method, but may be formed using a thin film forming method using a metal mask such as a photolithography method.

  The surface acoustic wave device of the present invention can be applied to bandpass filters and communication devices for communication devices such as mobile phones and PHS (Personal Handy Phone). This bandpass filter is a bandpass filter used in a transmission circuit of a communication device having a transmission circuit that outputs an antenna transmission signal to an antenna via a duplexer, and includes the surface acoustic wave device of the present invention. It is. The band-pass filter is a band-pass filter used in a reception circuit of a communication device including a reception circuit that receives an antenna reception signal via a duplexer and separates the reception signal from a carrier signal of the antenna reception signal. 1 is a bandpass filter including a surface acoustic wave device according to the present invention.

  Further, the communication device of the present invention includes a bandpass including a mixer that superimposes a transmission signal on a carrier wave signal (carrier signal) to be an antenna transmission signal, and a surface acoustic wave device of the present invention that attenuates an unnecessary signal of the antenna transmission signal. The communication device includes a transmission circuit including a filter and a power amplifier that amplifies the antenna transmission signal and outputs the amplified antenna transmission signal to the antenna through the duplexer. The communication apparatus of the present invention also includes a bandpass including a low noise amplifier that amplifies an antenna reception signal received by an antenna and passed through a duplexer, and a surface acoustic wave device of the present invention that attenuates an unnecessary signal of the amplified antenna reception signal. The communication device includes a reception circuit including a filter and a mixer that separates the reception signal from the carrier wave signal of the antenna reception signal.

  FIG. 12 shows an example of a block circuit diagram of a high-frequency circuit having a band-pass filter incorporated in a mobile phone as a communication device. The transmission signal (high frequency signal) is superposed on the carrier wave signal by the mixer 220 to form an antenna transmission signal. The unnecessary signal is attenuated by the surface acoustic wave device 221 that is a bandpass filter, amplified by the power amplifier 222, and then the isolator 223. And the surface acoustic wave duplexer (duplexer) 215 and radiated from the antenna 214. The antenna reception signal received by the antenna 214 passes through the surface acoustic wave demultiplexer 215 and is amplified by the low noise amplifier 216. After the unnecessary signal is attenuated by the surface acoustic wave device 217 which is a bandpass filter, the amplifier The signal is re-amplified at 218 and converted to a low frequency signal by the mixer 219.

  The communication device of the present invention only needs to include at least one of the transmission circuit and the reception circuit, and may include both.

  Since the band-pass filter and the communication device of the present invention have the surface acoustic wave device of the present invention, they have excellent durability and high reliability.

  Hereinafter, the result of having manufactured and measured about the surface acoustic wave apparatus S1 produced along the above-mentioned embodiment is demonstrated.

As the piezoelectric substrate 1, a 36 ° Y cut-X propagation LiTaO ₃ crystal was used. The piezoelectric substrate 1 had a chip size of 1.1 mm × 1.5 mm. The mounting substrate 60 is an alumina substrate having a chip size of 70 mm × 70 mm and a thickness of 250 μm. On this alumina substrate, Au and Ni having a total film thickness of 1 μm were formed by using an electroless plating method.

  As shown in FIG. 6, in order to use the lift-off method other than the portion where the base electrode 2 and the annular electrode 11 drawn from the IDT electrode 8 are formed, masking was performed with a photoresist film 22. And the coupling electrode E (the wiring electrode 12 and the annular electrode 11) was formed using the sputtering method.

  In the coupling electrode E, the base electrode 2 is formed of an Al—Cu alloy, the adhesion electrode layer 3 is formed of Cr, the barrier metal electrode layer 4 is formed of Ni, and the outermost electrode layer 6 is formed of Au. .

  The thickness of each electrode layer forming the coupling electrode E is about 180 nm for the base electrode 2, about 20 nm for the adhesion electrode layer 3, and about about 20 nm for the barrier metal electrode layer 4 including the impurity-containing layer 4 </ b> B. The thickness was 1 μm, and the electrode layer 6 was about 200 nm.

  Inside the barrier metal electrode layer 4, two layers of impurity containing layer 4 </ b> B having a high carbon and sulfur concentration are formed by switching to a Ni target material having a high carbon and sulfur concentration and performing sputtering during film formation using the sputtering method. (See FIG. 2).

  On the wiring connection electrode 62 and the annular connection electrode 66 of the mounting substrate 60, a solder paste to be the connection body 63 and the annular sealing material 65 was applied in advance using a screen printing method. The line width of the applied solder paste was about 100 μm.

  Then, after face-down mounting at a position where the wiring connection electrode 62 and the wiring electrode 12 that face each other are connected, reflow melting is performed at a temperature of 240 ° C. for 5 minutes in a reflow furnace. Cured.

  Next, an epoxy resin 64 was applied to the upper portion of the surface acoustic wave element S1 using a potting method, and then cured by heating at a temperature of 150 ° C. for 5 minutes in a drying furnace.

  Finally, individual surface acoustic wave elements S1 were formed by dicing at the separation positions between the chips, and the surface acoustic wave device 90 of 2.5 mm × 2.0 mm was completed. The height of the surface acoustic wave device 90 at this time was about 0.7 mm.

  FIG. 7 is a graph showing the results of SIMS (Secondary Ion Mass Spectrometry) analysis of the metal elements constituting the layer in the depth direction from the surface of the coupling electrode E.

  FIG. 8 is a graph showing SIMS analysis results of the metal elements constituting the layers in the depth direction from the surface of the bonding electrode (electrode pad) 112 (see FIG. 9) as a conventional technique.

  SIMS is an accelerated and narrowed primary ion beam (oxygen, cesium, etc. ion beam) that is irradiated onto a material in a vacuum, and secondary ions out of particles that are ejected from the surface of the material by sputtering are extracted by an electric field. This is a method to analyze data. Then, the absolute concentration is converted by comparing with a standard sample.

  In FIG. 7, in the intermediate layer 7 (see FIG. 2), the barrier metal electrode layer 4 has carbon (C) and sulfur (S) impurity peaks observed in the Ni layer (near 200 sec to 300 sec, 400 sec to around 500 sec). Therefore, it can be seen that the barrier metal electrode layer 4 is a laminate in which the Ni layer is interposed by two impurity-containing layers 4B. In the impurity-containing layer 4B, the carbon concentration is about 3.16% by weight, and the sulfur concentration is about 0.5% by weight.

  On the other hand, in FIG. 8, in the intermediate layer 117 (see FIG. 9), it can be seen that the barrier metal electrode layer 115 is formed of a single Ni layer.

  In the following, the film stress applied to the coupling electrode E according to the embodiment of the present invention and the bonding electrode (electrode pad) 112 as a conventional technique will be compared.

Table 1 shows the results of measuring the film stress applied to the intermediate layer 7 of the coupling electrode E and the intermediate layer 117 of the bonding electrode (electrode pad) 112.

  In Table 1, as one embodiment of the present invention, a coupling electrode E having an impurity-containing layer 4B containing carbon and sulfur as impurities in the barrier metal electrode layer 4 included in the intermediate layer 7 (see FIG. 2). As a conventional technique, as shown in FIG. 10, a Ni layer 115 included in the intermediate layer 117 is compared with a bonding electrode 112 that does not include an impurity-containing layer.

At this time, in the coupling electrode E, the film stress of the electrode structure was 189 N / m ² . In comparison, in the bonding electrode 112, the film stress of the electrode structure was 882 N / m ² . As a result, by using the coupling electrode E according to the present invention, the film stress could be reduced to about ¼. Therefore, the coupling electrode E can prevent film peeling at each electrode layer interface caused by film stress, and can improve the reliability of the surface acoustic wave device.

Furthermore, mechanical resistance was evaluated by a free drop test using the same surface acoustic wave device S1 and comparative sample prepared for the above-described film stress measurement. Each test sample was dropped freely from a height of 1.8 meters onto the concrete surface. The number of repetitions of free fall in the durability test is 10, 30, 50, 100 times. For each set, 30 surface acoustic wave devices S1 and comparative samples were prepared and used as test samples. Samples with deteriorated filter characteristics were regarded as defective, and the cumulative number of defects was determined for each set. The results are shown in Table 2.

  In the surface acoustic wave device S1, no defective product was produced even after 100 times of free fall. On the other hand, in the comparative sample, the defect was already generated after 30 times of free fall. These data complement the above-described film stress measurement results and more realistically show the superiority of the surface acoustic wave device S1 according to this embodiment over the prior art.

  In addition, various design changes can be made within the scope of matters described in the claims.

1 is a plan view of a surface acoustic wave device according to an embodiment of the present invention. It is an expanded sectional view in the A-A 'line of the annular electrode in the surface acoustic wave apparatus of FIG. FIG. 2 is an enlarged cross-sectional view taken along line B-B ′ of a wiring electrode in the surface acoustic wave device of FIG. 1. 1 is a cross-sectional view of a surface acoustic wave device in which a surface acoustic wave element is mounted on a mounting substrate. It is an expanded sectional view for demonstrating the manufacturing method of the electrode for coupling | bonding. It is an expanded sectional view when the electrode for coupling is formed by the lift-off method. It is a graph which shows the SIMS analysis result of the metal element which comprises the layer to the depth direction from the surface of the electrode for joining. It is a graph which shows the SIMS analysis result of the metal element which comprises the layer to the depth direction from the surface of the electrode (electrode pad) for joining as a prior art. It is a schematic sectional drawing of the conventional typical surface acoustic wave apparatus. It is sectional drawing of the electrode pad contained in the conventional surface acoustic wave apparatus. It is sectional drawing of an electrode pad when formed by the lift-off method. 1 is a block circuit diagram of a high-frequency circuit having a band-pass filter in a communication device (mobile phone) using the surface acoustic wave device of the present invention as a band-pass filter. 1 is an enlarged cross-sectional view taken along the line AA ′ of the annular electrode in the surface acoustic wave device of FIG. 1 having a barrier metal electrode layer in which a base metal layer and an impurity-containing layer of the barrier metal electrode layer are formed one by one. FIG.

Explanation of symbols

1: piezoelectric substrate S1: surface acoustic wave element 2: base electrode 3: adhesion electrode layer 4: barrier metal electrode layer 4A: base material layer 4B of barrier metal electrode layer: impurity-containing layer 7: intermediate layer 8: IDT electrode (excitation) electrode)
9: Lead-out wiring 10: Protective film 11: Ring electrode 12: Wiring electrode E: Coupling electrode 60: Mounting substrate 90: Surface acoustic wave device

Claims (15)

A surface acoustic wave device in which a surface acoustic wave element is mounted on a mounting substrate by a wireless bonding method,
The surface acoustic wave element has an excitation electrode formed on the main surface of the piezoelectric substrate and a coupling electrode formed on the main surface of the piezoelectric substrate and connected to the electrode on the mounting substrate. ,
The coupling electrode is:
A base electrode formed on a main surface of the piezoelectric substrate using a metal material mainly composed of Al;
An intermediate layer formed on the base electrode,
The intermediate layer is a laminate of an adhesion electrode layer and a barrier metal electrode layer,
The barrier metal electrode layer is interposed between a base material layer made of Ni or Cu and a part of the base material layer in a thickness direction, and at least one material of carbon, sulfur, and oxygen is used as an impurity in the base material layer. A surface acoustic wave device comprising: an impurity-containing layer that is added , wherein the impurity concentration of the impurity-containing layer gradually decreases toward the outside in the thickness direction of the barrier metal electrode layer .   The surface acoustic wave device according to claim 1, wherein the coupling electrode is an annular electrode formed at a position surrounding an outer periphery of the excitation electrode.   The surface acoustic wave device according to claim 1, wherein the coupling electrode is a wiring electrode connected to the excitation electrode. The barrier metal electrode layer, the surface acoustic wave device according to any one of claims 1 to 3 consisting of Ni. The surface acoustic wave device according to claim 4, wherein the coupling electrode further includes an Au electrode layer laminated on the intermediate layer .   The thickness of the said barrier metal electrode layer is a surface acoustic wave apparatus in any one of Claims 1-5 which exists in the range of 0.5 micrometer-1.5 micrometers.   The surface acoustic wave device according to claim 1, wherein the adhesion electrode layer includes at least one material of Cr, Ti, V, and Pt. An excitation electrode and a coupling electrode to be connected to the electrode on the mounting substrate are formed on the main surface of the piezoelectric substrate to produce a surface acoustic wave device, and the surface acoustic wave device is formed on the mounting substrate. A method of manufacturing a surface acoustic wave device to be mounted by wireless bonding,
The coupling electrode is:
A first step of forming a base electrode of the coupling electrode on a main surface of the piezoelectric substrate using a metal material mainly composed of Al;
A second step of forming a contact electrode layer on the base electrode;
The adhesion electrode layer, a shall be manufactured by a third step of forming a barrier metal electrode layer,
In the third step, the barrier metal electrode layer forms a first base material layer by sputtering using a target made of Ni or Cu containing at least one material of carbon, sulfur and oxygen as an impurity. And a step of forming a second base material layer on the first base material layer by resuming the sputtering using the target after temporarily stopping the sputtering. A method of manufacturing a surface acoustic wave device formed . The piezoelectric substrate before forming the base electrode;
The base electrode before forming the adhesion electrode layer;
The adhesion electrode layer before forming the barrier metal electrode layer;
The surface of at least one of the barrier metal electrode layers including the impurity-containing layer is roughened by performing bombarding with at least one of argon ions, oxygen ions, and nitrogen ions. Manufacturing method of the surface acoustic wave device.   The method for manufacturing a surface acoustic wave device according to claim 8 or 9, wherein the coupling electrode is an annular electrode formed at a position surrounding an outer periphery of the excitation electrode.   The method for manufacturing a surface acoustic wave device according to claim 8, wherein the coupling electrode is a wiring electrode connected to the excitation electrode. The base material layer is composed of Ni, the production method of the surface acoustic wave device according to any one of claims 8 to claim 11. The mounting board has an annular connection electrode,
11. The surface acoustic wave device according to claim 10 , wherein the surface acoustic wave device is mounted on the mounting substrate by connecting the annular electrode and the annular connection electrode via an annular sealing material made of solder. Method.   14. The method for manufacturing a surface acoustic wave device according to claim 8, wherein a thickness of the barrier metal electrode layer is in a range of 0.5 μm to 1.5 μm.   The method of manufacturing a surface acoustic wave device according to claim 8, wherein the adhesion electrode layer includes at least one material of Cr, Ti, V, and Pt.

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