JP2016208413A - Acoustic wave device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an acoustic wave device in which a space between wires is narrowed and downsized.SOLUTION: The acoustic wave device comprises: a substrate; a first elastic wave resonator P3 (40) and a second elastic wave resonator P2 (40) provided on the substrate; a first wire 30a electrically connected to the first elastic wave resonator and provided between the first elastic wave resonator and the second elastic wave resonator on the substrate; and a second wire 32a that is electrically connected to the second elastic wave resonator, provided between the first elastic wave resonator and the second elastic wave resonator on the substrate, has a different potential from the first wire, and is thicker than the first wire.SELECTED DRAWING: Figure 3

Description

  The present invention relates to an acoustic wave device, for example, an acoustic wave device in which wiring is provided between acoustic wave resonators.

  Elastic wave devices are used in filters for mobile communication. In an acoustic wave device, a plurality of acoustic wave resonators are formed on a substrate. A plurality of wirings formed between the acoustic wave resonators may be formed adjacent to each other (Patent Document 1).

JP 2000-114916 A

  In order to reduce the size of the acoustic wave device, it is conceivable to reduce the interval between adjacent wirings. However, if the wiring interval of different potentials is narrowed, parasitic capacitance is generated between the wirings, and the characteristics of the acoustic wave device are deteriorated. In addition, the wiring may be short-circuited due to the stress of the wiring, and electrostatic breakdown may occur due to the discharge between the wirings. Thus, it is difficult to narrow the wiring interval.

  The present invention has been made in view of the above problems, and an object of the present invention is to reduce the acoustic wave device by reducing the wiring interval.

  The present invention provides a substrate, a first acoustic wave resonator and a second acoustic wave resonator provided on the substrate, and the first acoustic wave resonator electrically connected to the substrate, on the substrate, and A first wiring provided between the first elastic wave resonator and the second elastic wave resonator, and electrically connected to the second elastic wave resonator, on the substrate and on the first elastic wave resonator An acoustic wave device comprising: a second wiring provided between a wave resonator and the second acoustic wave resonator, having a potential different from that of the first wiring and being thicker than the first wiring. It is.

  In the above configuration, the second wiring may be directly connected to a pad provided with a bump, and the first wiring may not be directly connected to a pad provided with a bump.

  In the above structure, the second wiring may be closer to an input pad for inputting a signal than the first wiring.

  In the above configuration, the extending directions of the first wiring and the second wiring may be parallel.

  In the above configuration, the first acoustic wave resonator and the second acoustic wave resonator each include a first bus bar and a second bus bar, the first wiring is electrically connected to the first bus bar, and the second The wiring may be electrically connected to the second bus bar, and the extending direction of the first wiring and the second wiring may be parallel to the extending direction of the first bus bar and the second bus bar.

  In the above configuration, one or more series resonators connected in series between the input terminal and the output terminal, a plurality of parallel resonators connected in parallel between the input terminal and the output terminal, The plurality of parallel resonators may include the first elastic wave resonator and the second elastic wave resonator.

  In the above configuration, the multimode acoustic wave filter formed on the substrate is provided, the first wiring is electrically connected to a signal terminal of the multimode acoustic wave filter, and the second wiring is the multiple multiplexing It can be set as the structure electrically connected to the ground terminal of a mode elastic wave filter.

  The said structure WHEREIN: A part of said 2nd wiring can be set as the structure which cross | intersects on the said 1st wiring.

  In the above-described configuration, a first multimode elastic wave filter and a second multimode elastic wave filter formed on the substrate are provided, and the first wiring includes a signal terminal of the first multimode elastic wave filter and the first multimode elastic wave filter. A second multi-mode elastic wave filter connected to a signal terminal of the multi-mode elastic wave filter; and the second wiring is connected to a ground terminal of at least one of the first multi-mode elastic wave filter and the second multi-mode elastic wave filter; can do.

  According to the present invention, it is possible to reduce the acoustic wave device by narrowing the wiring interval.

FIG. 1 is a circuit diagram of a duplexer in which the acoustic wave device according to the first embodiment is used. FIG. 2 is a plan view of the acoustic wave device according to the first embodiment. FIG. 3 is an enlarged view of the vicinity of the area A1 in FIG. 4 is a cross-sectional view taken along line BB in FIG. FIG. 5 is a plan view of the acoustic wave device according to the first modification of the first embodiment. FIG. 6 is a plan view of the acoustic wave device according to the second modification of the first embodiment. FIG. 7 is a plan view of the acoustic wave device according to the second embodiment. FIG. 8 is a plan view of the acoustic wave device according to the first modification of the second embodiment. FIG. 9A to FIG. 9D are cross-sectional views (part 1) illustrating the method for manufacturing the acoustic wave device according to the first and second embodiments and the modifications thereof. FIG. 10A to FIG. 10D are cross-sectional views (part 2) illustrating the method for manufacturing the acoustic wave device according to the first and second embodiments and the modifications thereof.

  Embodiments of the present invention will be described below with reference to the drawings.

  Example 1 is an example of a transmission filter as an elastic wave device. FIG. 1 is a circuit diagram of a duplexer in which the acoustic wave device according to the first embodiment is used. As shown in FIG. 1, a transmission filter 70 is connected between the antenna terminal Ant and the transmission terminal Tx, and a reception filter 72 is connected between the antenna terminal Ant and the reception terminal Rx. The transmission filter 70 outputs a signal in the transmission band among the signals input from the transmission terminal Tx to the antenna terminal Ant. The reception filter 72 outputs a signal in the reception band among the signals input to the antenna terminal Ant to the reception terminal Rx.

FIG. 2 is a plan view of the acoustic wave device according to the first embodiment. As shown in FIG. 2, in the transmission filter 100, a plurality of acoustic wave resonators 40, wirings 30 and 32, and pads 34 are formed on the substrate 10. The substrate 10 is a piezoelectric substrate such as a LiTaO ₃ substrate or a LiNbO ₃ substrate. The substrate 10 may be a substrate in which a piezoelectric substrate is attached to a support substrate such as a sapphire substrate. The acoustic wave resonator 40 is a surface acoustic wave resonator, for example. The acoustic wave resonator 40 is a one-port resonator, and includes an IDT (Interdigital Transducer) and reflectors R provided on both sides thereof. The wirings 30 and 32 and the pad 34 are formed of a metal film such as a copper film or a gold film formed on the substrate 10. The wirings 30 and 32 connect between the acoustic wave resonator 40 and between the acoustic wave resonator 40 and the pad 34. The wiring 32 is thicker than the wiring 30. The pad 34 has the same layer structure as the wiring 32 and the same thickness. Bumps 36 are formed on the pads 34. The bump 36 is, for example, a gold bump or a copper bump, for example, a stud bump or a plating bump.

  The transmission filter 100 is a ladder type filter. The series resonators S1 to S4 are connected in series between a pad 34 that is an antenna terminal Ant (output terminal) and a pad 34 that is a transmission terminal Tx (input terminal). The parallel resonators P1 to P3 are connected in parallel between the antenna terminal Ant and the transmission terminal Tx. One end of the parallel resonators P1 to P3 is connected to a pad 34 that is a ground terminal GND.

  FIG. 3 is an enlarged view of the vicinity of the area A1 in FIG. As shown in FIG. 3, the acoustic wave resonator 40 includes IDTs and reflectors R formed on both sides of the IDT. The IDT includes a pair of comb electrodes 48. The comb electrode 48 includes a plurality of electrode fingers 44 and a bus bar 46 to which the electrode fingers 44 are connected. The pair of comb-shaped electrodes 48 oppose each other so that the electrode fingers 44 are arranged almost alternately. The wirings 30a (first wiring) and 32a (second wiring) are electrically connected to the bus bar 46, respectively.

  4 is a cross-sectional view taken along line BB in FIG. As shown in FIG. 4, the electrode finger 44, the bus bar 46, and the lowermost layer 15 of the wirings 30 a and 32 a are formed of the metal film 12. The metal film 12 is, for example, an aluminum film, a titanium film, or a copper film. The wiring 30a includes a lowermost layer 15, a barrier layer 16a, and a seed layer 16b. The wiring 32a includes a lowermost layer 15, a barrier layer 16a, a seed layer 16b, a lower layer 18, a barrier layer 19, and an upper layer 20. The barrier layer 16a, seed layer 16b, lower layer 18, barrier layer 19 and upper layer 20 are, for example, a titanium layer, a copper layer, a copper layer, a palladium layer, and a gold layer. For example, the wiring 32 a may not include the barrier layer 19 and the upper layer 20. The wiring 32 a has the upper layer 20 but may not have the barrier layer 19.

As the wirings 30a and 32a, a laminated film of one or a plurality of layers can be used. As the layers mainly functioning as the wirings 30a and 32a (for example, the seed layer 16b, the lower layer 18 and the upper layer 20), it is preferable to use a gold layer, a copper layer, an aluminum layer, or a composite layer thereof having a low electric resistance. In the case of having a plurality of layers of different materials, it is preferable to provide a barrier layer that suppresses interdiffusion of atoms between films of different materials. When interdiffusion occurs, the strength decreases or the resistance increases. For example, a nickel layer, a titanium layer, or a palladium layer is used as the barrier layer. The thickness of the barrier layer is 0.05 μm to 2 μm from the viewpoint of suppressing diffusion. The film thickness T1 of the wiring 30a is, for example, 0.1 μm to 0.5 μm. The film thickness T2 of the wiring 32a is, for example, 1 μm to 10 μm. A distance D1 between the wirings 30a and 32a is, for example, 5 μm to 20 μm. Each layer of the wirings 30a and 32a can be formed using a plating method, a vapor deposition method, or a sputtering method. The size of the substrate 10 is, for example, 0.3 mm ² to 1.5 mm ² , and the thickness of the substrate 10 is, for example, 1 μm to 500 μm.

  As shown in FIG. 2, as shown in region A1, between the parallel resonators P2 and P3, the wiring 32a electrically connected to the parallel resonator P2 and the wiring electrically connected to the parallel resonator P3 30a is provided adjacently. As shown in the region A2, between the parallel resonators P1 and P2, the wiring 32a electrically connected to the parallel resonator P1 and the wiring 30a electrically connected to the parallel resonator P2 are adjacent to each other. Is provided. The wiring 32a is a ground potential and is different from the ground potential of the wiring 30a.

  In the case where the adjacent wirings are both thick wirings 32, if the interval between the wirings 32 is narrowed, parasitic capacitance is generated between the wirings, and the characteristics (for example, insertion loss) of the acoustic wave device are deteriorated. Further, the wiring 32 may be short-circuited due to the stress of the wiring 32. Further, electrostatic discharge may occur due to discharge between the wirings 32. Thus, it is difficult to narrow the interval between the wirings 32.

  According to the first embodiment, in the regions A1 and A2 where the wirings are adjacent between the acoustic wave resonators 40, one of the wirings 30a and 32a having different potentials is made thicker than the wiring 30a. Thereby, compared with the case where the thick wiring 32 adjoins, the area which wiring 32a and 30a oppose becomes small. Therefore, parasitic capacitance between wirings can be suppressed, and characteristics such as insertion loss can be improved. Further, since the wiring 30a has a lower stress than the wiring 32a, a short circuit of the wiring 32 due to the stress of the wiring 32 can be suppressed. Furthermore, electrostatic breakdown between the wirings 32a and 30a can be suppressed. Therefore, the distance D1 between the wirings 30a and 32a can be narrowed, and the transmission filter 100 can be downsized. For example, the distance D1 can be made smaller than the film thickness T1 of the wiring 30a.

  As will be described later, when the thick wiring 32a is formed using a plating method, if the interval between the thick wirings 32a is narrow, a resist pattern that is a mask for plating may not be appropriately formed. In this case, the wiring may be short-circuited, or a resistor may remain on the substrate 10, which may cause reliability concerns. In Example 1, since one of the adjacent wirings 30a and 32a is thin wiring 30a, a resist pattern can be appropriately formed.

  When the aspect ratio T2 / D1 between the film thickness T2 of the wiring 32a and the distance D1 is larger than 2, there is a high possibility that the resist pattern is not properly formed. Therefore, T2 / D1 is preferably 2 or less. Also, from the viewpoint of miniaturization, T2 / D1 is preferably 0.025 or more.

  Of the adjacent wirings 30a and 32a, it is preferable to increase the thickness of the wiring 32a that is directly connected to the pad 34 provided with the bumps 36. Further, it is preferable to thin the wiring 30a that is not directly connected to the pad 34 provided with the pump 36. The bumps 36 are bonded to, for example, a module substrate. Heat generated in the acoustic wave device is released to the module substrate through the bumps 36. The thick wiring 32 has better thermal conductivity than the thin wiring 30. Therefore, heat can be efficiently released by increasing the thickness of the wiring 32a directly connected to the pad 34. The pad 34 corresponding to the ground terminal GND has good heat dissipation through a module substrate or the like. Therefore, the pad 34 to which the wiring 32a is directly connected is preferably a pad corresponding to the ground terminal GND.

  FIG. 5 is a plan view of the acoustic wave device according to the first modification of the first embodiment. As shown in FIG. 5, in the transmission filter 102, not only the regions A1 and A2, but also the wiring directly connected to the pad 34 provided with the bump 36 is the thick wiring 32, and the wiring not directly connected to the bump 36 is used. Thin wiring 30 is used. For example, a thin wiring 30 is used as a wiring connecting the acoustic wave resonators 40. Other configurations are the same as those of the first embodiment, and the description thereof is omitted. Also in the first modification of the first embodiment, heat can be efficiently radiated from the bumps 36.

  As in the first embodiment, only in the regions A1 and A2 where wirings with different potentials are adjacent, the wiring that is not directly connected to the pad 34 may be the thin wiring 30, and the other wiring may be the thick wiring 32. As a result, the wiring that does not cause a problem of parasitic capacitance can be thickened, so that heat dissipation and power durability can be improved. Further, as in the first modification of the first embodiment, the thin wiring 30 may be provided in a region other than the regions A1 and A2. In this way, at least in the regions A1 and A2 where the wirings having different potentials are adjacent, one wiring may be thinner than the other.

  FIG. 6 is a plan view of the acoustic wave device according to the second modification of the first embodiment. In the transmission filter 104, the wirings 30a and 32a are adjacent to each other between the parallel resonators P2 and P3 in the region A3. The wiring 30a is connected to a node between the series resonators S3 and S4. The wiring 32a is connected between the series resonators S2 and S3. Both the wirings 30 a and 32 a are not directly connected to the pad 34. Other configurations are the same as those of the first embodiment, and the description thereof is omitted.

  According to the second modification of the first embodiment, the wiring 32a is closer to the pad 34 (pad to which a signal is input) corresponding to the transmission terminal Tx than the wiring 30a. A resonator near the pad 34 corresponding to the transmission terminal Tx generates more heat than a far resonator. Therefore, the wiring close to the input pad 34 is a thick wiring 32. Thereby, efficient heat dissipation becomes possible.

  According to Example 1 and its modification, the extending directions of the wirings 30a and 32a are parallel as shown in FIG. When parallel wirings are adjacent to each other, an increase in parasitic capacitance between the wirings, a short circuit between the wirings, and / or electrostatic breakdown between the wirings is likely to occur. Therefore, the wiring 32a is made thicker than 30a. Thereby, a wiring space | interval can be narrowed and an elastic wave device can be reduced in size.

  The wiring 30a is electrically connected to the bus bar 46 of the parallel resonator P3 (first elastic wave resonator), and the wiring 32a is electrically connected to the bus bar 46 of the parallel resonator P2 (second elastic wave resonator). Has been. The extending direction of the wirings 30 a and 32 a is parallel to the extending direction of the bus bar 46. When the acoustic wave resonator 40 includes the bus bar 46, the length in which the wirings 30a and 32a face each other is increased. When the opposing length of the wiring is large, parasitic capacitance between the wirings increases, a short circuit between the wirings and / or electrostatic breakdown between the wirings easily occurs. Therefore, the wiring 32a is made thicker than 30a. Thereby, a wiring space | interval can be narrowed and an elastic wave device can be reduced in size.

  When adjacent resonators are parallel resonators, opposing wirings have different potentials. Therefore, an increase in parasitic capacitance between wirings, a short circuit between wirings, and / or electrostatic breakdown between wirings are likely to occur. Therefore, the wiring 32a is made thicker than 30a. Thereby, a wiring space | interval can be narrowed and an elastic wave device can be reduced in size.

  The second embodiment is an example in which the acoustic wave device is the reception filter 72 of FIG. FIG. 7 is a plan view of the acoustic wave device according to the second embodiment. As shown in FIG. 7, in the reception filter 106, an elastic wave resonator 40 and a multimode elastic wave filter 42 are formed on the substrate 10. The multimode acoustic wave filter 42 is a dual mode surface acoustic wave filter DMS1 and DMS2. DMS1 and DMS2 are connected in parallel. The input terminals of DMS1 and DMS2 are connected to the antenna terminal Ant via the resonator R1. The grounds of DMS1 and DMS2 are connected to the ground terminal GND. Series resonators S1 and S2 are connected in series between the output terminals of DMS1 and DMS2 and the reception terminal Rx, and parallel resonators P1 and P2 are connected in parallel. Series resonators S1 and S2 are divided into two and three, respectively. The parallel resonators P1 and P2 are divided into two and four, respectively.

  In the region A4, wirings 32b and 30b are adjacent between the resonators R1 and DMS1, between the resonators R1 and DMS2, between the DMS1 and the series resonator S1, and between the DMS2 and the parallel resonator P1. ing. A wiring through which a signal propagates from the antenna terminal Ant to the receiving terminal Rx is a thin wiring 30b. The wiring directly connected to the ground terminal GND is a thick wiring 32b. In the region A5, the wirings 30a and 32a are adjacent between the parallel resonators P1 and P2. The thick wiring 32 a is directly connected to the pad 34 provided with the bump 36. The thin wiring 30 a is not directly connected to the pad 34 provided with the bump 36. Other configurations are the same as those of the first embodiment, and the description thereof is omitted.

  According to the second embodiment, the wiring 30 b is electrically connected to the input terminal and the output terminal (that is, the signal terminal) of the multimode elastic wave filter 42, and the wiring 32 b is electrically connected to the ground terminal of the multimode elastic wave filter 42. Connected. The signal terminal and the ground terminal of the multimode acoustic wave filter 42 are adjacent to each other. Therefore, the wiring 32a is made thicker than 30a. Thereby, a wiring space | interval can be narrowed and an elastic wave device can be reduced in size.

  FIG. 8 is a plan view of the acoustic wave device according to the first modification of the second embodiment. As shown in FIG. 8, in the reception filter 108, resonators R2, DMS3, and DMS4 are connected in series between the antenna terminal Ant and the reception terminal Rx. The DMS 3 includes IDT 11 to IDT 13 and a reflector R. IDTs 11 to 13 are arranged in the propagation direction of the elastic wave. The DMS 4 includes IDT 21 to IDT 23 and a reflector R.

  One end of the IDT 12 of the DMS 3 is connected to the antenna terminal Ant via the resonator R2. The other end of the IDT 12 is connected to the ground terminal GND. One ends of the IDT 11 and IDT 13 are connected to the ground terminal GND. The other ends of IDT 11 and IDT 13 are connected to one ends of IDTs 21 and 23 of DMS 4 via wiring 30c, respectively. The other ends of the IDTs 21 and 23 are connected to a ground terminal. One end of the IDT 22 is connected to a ground terminal. The other end of the IDT 22 is connected to the receiving terminal Rx. Other configurations are the same as those of the second embodiment, and the description thereof is omitted.

  In the region A6, wirings 30c and 32c are provided adjacent to each other between DMS3 and DMS4. The wiring 32c intersects the wiring 30c. A dielectric layer is provided between the wirings 30c and 32c. There may be a gap between the wirings 30c and 32c. The wiring 32c is directly connected to the pad 34 on which the bump 36 is provided. The wiring 30 c is not directly connected to the pad 34. Thus, the acoustic wave device can be reduced in size by intersecting the thin wiring 30c and the thick wiring 32c. In order to easily cross the two wirings, it is preferable that a part of the thick wiring 32c crosses the thin wiring 30c.

  When connecting the signal terminals of DMS3 (first multimode elastic wave filter) and DMS4 (second multimode elastic wave filter), an elastic wave device is obtained by crossing the wiring connecting the signal terminals and the ground wiring. Can be downsized. Therefore, it is preferable that the wiring 30c connects the DMS3 signal terminal and the signal terminal of the DMS4, and the wiring 32c is connected to at least one of the ground terminals of the DMS3 and DMS4.

  For at least one of the transmission filter 70 and the reception filter 72 of the duplexer shown in FIG. 1, the transmission filter of the first embodiment and its modification or the reception filter of the second embodiment and its modification can be used.

  FIG. 9A to FIG. 10D are cross-sectional views showing a method for manufacturing an acoustic wave device according to the first and second embodiments and their modifications. As shown in FIG. 9A, a metal film 12 is formed on the substrate 10. The substrate 10 is a piezoelectric substrate such as a lithium tantalate substrate or a lithium niobate substrate. The metal film 12 is, for example, an aluminum film or a titanium film. The metal film 12 is formed using, for example, a sputtering method and an etching method. An elastic wave resonator 40 is formed by the metal film 12. The film thickness of the metal film 12 is, for example, 100 nm to 500 nm. The metal film 12 may be a copper film or a gold film. The metal film 12 forms the lowermost layer 15 of the wirings 30 and 32 and the wiring 30c.

  As shown in FIG. 9B, the protective film 14 is formed on the acoustic wave resonator 40 and the wiring 30c. The protective film 14 is a silicon oxide film having a thickness of 20 nm, for example. The protective film 14 is formed using, for example, a sputtering method and an etching method. As shown in FIG. 9C, the dielectric film 17 is formed so as to cover the wiring 30c. The dielectric film 17 is, for example, an insulator and resin.

  As shown in FIG. 9D, a mask layer 50 is formed on the substrate 10 so that the opening 52 is formed in a region where the wiring 32 and the wiring 30a are to be formed. The mask layer 50 is a photoresist, for example, and is formed using a photolithography method. The film thickness of the mask layer 50 is preferably set to 2 μm or more in order to obtain a desired resolution in the photolithography method and to lift off the seed layer 16 described later. The mask layer 50 preferably has heat resistance that can withstand subsequent baking.

  As shown in FIG. 10A, the seed layer 16 is formed on the entire surface of the substrate 10 so as to cover the mask layer 50. The seed layer 16 is, for example, a titanium film having a thickness of 0.2 μm and a gold film having a thickness of 0.15 μm from the substrate 10 side. The seed layer 16 is formed using, for example, a vapor deposition method. The seed layer 16 may be a titanium film having a thickness of 0.1 μm and a copper film having a thickness of 0.3 μm from the substrate 10 side. The seed layer 16 may be formed using a sputtering method, but is preferably formed using an evaporation method because a lift-off method is used. The film on the substrate 10 side of the seed layer 16 is an adhesion film and a barrier layer that improve adhesion to the metal film 12. When the metal film 12 is an aluminum film, the adhesion film is, for example, a titanium film. The film on the upper side of the seed layer 16 functions as a plating seed and is preferably made of the same material as the plating layer.

  As shown in FIG. 10B, a mask layer 54 is formed on the seed layer 16 so that an opening 56 is formed in a region where the wiring 32 is to be formed. A mask layer 54 is formed on the seed layer 16 to be the wiring 30a. The mask layer 54 is a photoresist film having a thickness of 7 μm, for example, and is formed using a photolithography method. The film thickness of the mask layer 54 is set so as to cover the step of the seed layer 16 and be thicker than the plating layer 22, and is, for example, 5 μm to 20 μm.

  As shown in FIG. 10C, the plating layer 22 is formed in the opening 56. The plating layer 22 includes a lower layer 18, a barrier layer (not shown), and an upper layer 20 from the substrate side. The lower layer 18 is, for example, a copper layer having a thickness of 3 μm. The barrier layer is a palladium layer having a thickness of 0.3 μm, for example. The upper layer 20 is a gold layer having a thickness of 1 μm, for example. The plating layer 22 is formed by supplying an electric current from the seed layer 16 and using an electrolytic plating method. The lower layer 18 is preferably made of a material that can be thickened, has a low electrical resistivity, and is nonmagnetic. For this reason, the lower layer 18 is preferably a copper layer or a gold layer. The film thickness of the lower layer 18 is preferably, for example, 1 μm or more in order to reduce the resistance of the wirings 30 and 32. When forming a stud bump on the plating layer 22, the upper layer 20 is preferably a gold layer. The barrier layer suppresses interdiffusion caused by heating or aging of the lower layer 18 and the upper layer 20. When the lower layer 18 is a copper layer and the upper layer 20 is a gold layer, the barrier layer is preferably a palladium layer or a nickel layer having a thickness of about 0.2 μm. The upper layer 20 can also be formed using an electroless plating method. In this case, the film thickness of the upper layer 20 is, for example, 0.4 μm. In addition, the barrier layer and the upper layer 20 can be formed using a vapor deposition method. In this case, the barrier layer is, for example, a titanium layer having a thickness of 0.2 μm, and the upper layer 20 is a gold layer having a thickness of 0.4 μm.

  As shown in FIG. 10D, the mask layers 50 and 54 are removed using, for example, an organic solvent. At this time, the seed layer 16 formed between the mask layers 50 and 54 is lifted off. In order to lift off the seed layer 16, an organic solvent may be injected at a high pressure. Moreover, you may ultrasonically wash in an organic solvent. As a result, wirings 32 and 32 a are formed from the metal film 12, the seed layer 16, and the plating layer 22. A wiring 32 c is formed from the seed layer 16 and the plating layer 22. A wiring 30 a is formed from the metal film 12 and the seed layer 16. A wiring 30 c is formed from the metal film 12. In the region A7, a thick wiring 32a and a thin wiring 30a are formed. In the region A8, the thin wiring 30c and the thick wiring 32c are formed.

  As shown in FIG. 9A, the metal film 12 is formed on the substrate 10 in the region to be the acoustic wave resonator 40 and the wirings 30 a, 30 c, 32, and 32 a. As shown in FIG. 9B, the mask layer 50 (the opening 52 (first opening) is formed on the metal film 12 in the region to be the wirings 30a, 32, 32a and 32c, and the region to be the wiring 30c is not the opening 52. First mask layer) is formed. As shown in FIG. 10A, the seed layer 16 is formed so as to contact the metal film 12 in the opening 52 and cover the mask layer 50. As shown in FIG. 10B, a mask layer 54 (second mask layer) is formed on the seed layer 16 so that the regions to be the wirings 32, 32a, and 32c become openings 56 (second openings). As shown in FIG. 10C, the plating layer 22 is formed on the seed layer 16 in the opening 56 by supplying power from the seed layer 16. As shown in FIG. 10D, by removing the mask layer 50 and the mask layer 54, the seed layer 16 other than the opening 52 is lifted off. Thereby, the thin wirings 30a and 30c and the thick wirings 32, 32a and 32c can be formed.

  In the first and second embodiments and the modifications thereof, the surface acoustic wave resonator has been described as an example of the elastic wave resonator. However, the elastic wave resonator may be a boundary acoustic wave resonator, a love wave resonator, or a piezoelectric thin film. A resonator may be used. In addition, although a transmission filter using a ladder filter and a reception filter using a DMS filter have been described as examples of the elastic wave device, other elastic wave devices may be used.

  Although the embodiments of the present invention have been described in detail above, the present invention is not limited to such specific embodiments, and various modifications and changes can be made within the scope of the gist of the present invention described in the claims. It can be changed.

DESCRIPTION OF SYMBOLS 10 Substrate 12 Metal film 14 Protective film 16 Seed layer 22 Plating layer 30, 32 Wiring 40 Elastic wave resonator 42 Multimode elastic wave filter

Claims (9)

A substrate,
A first acoustic wave resonator and a second acoustic wave resonator provided on the substrate;
A first wiring electrically connected to the first acoustic wave resonator and provided on the substrate between the first acoustic wave resonator and the second acoustic wave resonator;
Electrically connected to the second acoustic wave resonator, provided on the substrate and between the first acoustic wave resonator and the second acoustic wave resonator, at a potential different from that of the first wiring; A second wiring thicker than the first wiring;
An elastic wave device comprising:   2. The acoustic wave device according to claim 1, wherein the second wiring is directly connected to a pad provided with a bump, and the first wiring is not directly connected to a pad provided with a bump.   3. The acoustic wave device according to claim 1, wherein the second wiring is closer to an input pad for inputting a signal than the first wiring.   The elastic wave device according to claim 1, wherein extending directions of the first wiring and the second wiring are parallel. The first acoustic wave resonator and the second acoustic wave resonator each include a first bus bar and a second bus bar,
The first wiring is electrically connected to the first bus bar; the second wiring is electrically connected to the second bus bar;
The elastic wave device according to claim 4, wherein an extending direction of the first wiring and the second wiring is parallel to an extending direction of the first bus bar and the second bus bar. One or more series resonators connected in series between the input terminal and the output terminal;
A plurality of parallel resonators connected in parallel between the input terminal and the output terminal;
Comprising
6. The acoustic wave device according to claim 5, wherein the plurality of parallel resonators include the first acoustic wave resonator and the second acoustic wave resonator. Comprising a multimode acoustic wave filter formed on the substrate;
The first wiring is electrically connected to a signal terminal of the multimode acoustic wave filter,
3. The acoustic wave device according to claim 1, wherein the second wiring is electrically connected to a ground terminal of the multimode acoustic wave filter.   The acoustic wave device according to claim 1, wherein a part of the second wiring intersects the first wiring. Comprising a first multimode elastic wave filter and a second multimode elastic wave filter formed on the substrate;
The first wiring connects a signal terminal of the first multimode elastic wave filter and a signal terminal of the second multimode elastic wave filter;
9. The acoustic wave device according to claim 8, wherein the second wiring is connected to a ground terminal of at least one of the first multimode acoustic wave filter and the second multimode acoustic wave filter.

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