WO2023210393A1

WO2023210393A1 - Elastic wave filter

Info

Publication number: WO2023210393A1
Application number: PCT/JP2023/015010
Authority: WO
Inventors: 明野口
Original assignee: 株式会社村田製作所
Priority date: 2022-04-27
Filing date: 2023-04-13
Publication date: 2023-11-02

Abstract

Provided is an elastic wave filter wherein the heat occurring at an Interdigital Transducer (IDT) electrode can be efficiently dissipated and wherein the occurrence of the unnecessary capacitance between the IDT electrode and a reflector electrode is suppressed.　The elastic wave filter comprises: a substrate; at least one resonator formed on the substrate; a plurality of bumps formed on the substrate; and a plurality of wirings formed on the substrate. The resonator comprises: an IDT electrode having IDT electrode fingers; and a pair of reflector electrodes formed on the two sides of the IDT electrode in a direction orthogonal to the direction in which the IDT electrode fingers extend. The reflector electrodes each have a plurality of reflector electrode fingers. At least one of the two reflector electrodes of the at least one resonator is connected to a bump by a first wiring. The first wiring has at least two linear portions. The first wiring comprises at least one folded portion that connects two of the linear portions placed side by side.

Description

elastic wave filter

The present invention relates to an elastic wave filter, and more particularly, to an elastic wave filter in which a resonator is formed on a substrate.

Acoustic wave filters are widely used as filters for mobile communication devices and the like.　

When an acoustic wave filter is used, heat is generated in the IDT electrode of the resonator formed on the substrate. In elastic wave filters, efficiently dissipating the heat generated in the IDT electrode of the resonator is extremely important in suppressing deterioration of characteristics, suppressing fluctuations in characteristics, and further suppressing damage to the IDT electrode. is important.

An elastic wave filter is disclosed in Patent Document 1 (Japanese Unexamined Patent Publication No. 2017-204743).

The elastic wave filter of Patent Document 1 includes a plurality of resonators, and a predetermined reflector electrode of a predetermined resonator is connected to a ground pad by wiring. A bump is formed on the ground pad.

In the elastic wave filter of Patent Document 1, it is thought that the heat generated in the IDT electrode of the resonator is radiated to the ground pad and bump via the reflector electrode and wiring. That is, in the elastic wave filter of Patent Document 1, it is considered that heat generated in the IDT electrode of the resonator is efficiently dissipated due to such a structure.

JP2017-204743A

When the elastic wave filter of Patent Document 1 is used, the ground pad and the bumps formed on the ground pad are set to the ground potential. Therefore, the reflector electrode connected by wiring also becomes the ground potential.

Therefore, in the elastic wave filter of Patent Document 1, unnecessary capacitance (stray capacitance) is generated between the IDT electrode and the reflector electrode, and there is a risk that the characteristics of the elastic wave filter may deteriorate.

Therefore, the present invention efficiently dissipates the heat generated at the IDT electrode of the resonator to the bump via the reflector electrode and wiring, and at the same time prevents the generation of unnecessary capacitance between the IDT electrode and the reflector electrode. It is an object of the present invention to provide an elastic wave filter in which deterioration of characteristics is suppressed.

In order to solve the above problems, an elastic wave filter according to an embodiment of the present invention includes a substrate, at least one resonator formed on the substrate, a plurality of bumps formed on the substrate, and a substrate. a plurality of wirings formed on the resonator, the resonator having an IDT electrode having an IDT electrode finger; a pair of reflector electrodes formed on both sides, the reflector electrode includes a plurality of reflector electrode fingers, and the at least one resonator has at least one reflector electrode connected to the bump by a first wiring; It is assumed that one wiring is provided with at least two linear parts, and the first wiring is provided with at least one folded part that folds back the two linear parts arranged side by side.

In the acoustic wave filter according to one embodiment of the present invention, heat generated in the IDT electrode is efficiently radiated. Since the elastic wave filter according to one embodiment of the present invention can increase the length of the first wiring, it is possible to suppress the generation of unnecessary capacitance between the IDT electrode and the reflector electrode, and the deterioration of characteristics. can be suppressed.

FIG. 1 is a plan view of an elastic wave filter 100 according to a first embodiment. 1 is an equivalent circuit diagram of an elastic wave filter 100. FIG. 1 is a plan view of main parts of an elastic wave filter 100. FIG. FIG. 2 is an explanatory diagram of Example of Experiment 1, Comparative Example 1, and Comparative Example 2. 3 is a graph showing the reflection characteristics of Example of Experiment 1, Comparative Example 1, and Comparative Example 2. FIG. 3 is a plan view of main parts of an elastic wave filter 200 according to a second embodiment. FIG. 7 is a plan view of main parts of an elastic wave filter 300 according to a third embodiment. FIG. 4 is a plan view of main parts of an elastic wave filter 400 according to a fourth embodiment. FIG. 7 is a plan view of main parts of an elastic wave filter 500 according to a fifth embodiment. FIG. 7 is a plan view of main parts of an elastic wave filter 600 according to a sixth embodiment. It is an explanatory view (main part sectional view) of elastic wave filter 700 concerning a 7th embodiment. FIG. 8 is a plan view of main parts of an elastic wave filter 800 according to an eighth embodiment.

Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings.

Note that each embodiment is an illustrative example of an embodiment of the present invention, and the present invention is not limited to the content of the embodiment. Further, it is also possible to implement the contents described in different embodiments in combination, and the implementation contents in that case are also included in the present invention. In addition, the drawings are intended to aid understanding of the specification and may be drawn schematically, and the drawn components or the dimensional ratios between the components may be different from those described in the specification. The proportions of those dimensions may not match. In addition, there are cases where constituent elements described in the specification are omitted in the drawings or drawn with their numbers omitted.

[First embodiment]
1, 2, and 3 show an elastic wave filter 100 according to a first embodiment. However, FIG. 1 is a plan view of the elastic wave filter 100. FIG. 2 is an equivalent circuit diagram of the elastic wave filter 100. FIG. 3 is a plan view of essential parts of the elastic wave filter 100. Note that FIGS. 1 and 3 show the mounting surface side of the acoustic wave filter 100. Further, in FIGS. 1 and 3, arrows indicate that the horizontal direction in the drawings is the horizontal direction X of the elastic wave filter 100, and the vertical direction in the drawings is the vertical direction Y of the elastic wave filter 100. In the following description, the horizontal direction X and vertical direction Y of the elastic wave filter 100 may be referred to. Further, in FIG. 1, series arm resonators S11 to S15, S21, S22, parallel arm resonators P11 to P14, P21 to P23, etc., which will be described later, are sometimes schematically depicted.

As shown in FIG. 1, the elastic wave filter 100 includes a piezoelectric substrate 1. A duplexer consisting of the equivalent circuit shown in FIG. 2 is constructed on the main surface of the substrate 1. The duplexer includes a transmitter filter 10 and a receiver filter 20. First, with reference to FIG. 2, an equivalent circuit of the elastic wave filter 100 will be described.

The elastic wave filter 100 includes an antenna side terminal Ant, a transmitting side terminal Tx, a receiving side terminal Rx, and a ground terminal G.

A transmitting filter 10 is formed between the transmitting terminal Tx and the antenna terminal Ant. The transmitting side filter 10 is a ladder type filter including series arm resonators S11, S12, S13, S14, and S15 and parallel arm resonators P11, P12, P13, and P14.

In the transmission side filter 10, series arm resonators S11, S12, S13, S14, and S15 are connected in this order between the transmission side terminal Tx and the antenna side terminal Ant.

One end of the parallel arm resonator P11 is connected to the connection point between the series arm resonator S11 and the series arm resonator S12. Furthermore, one end of the parallel arm resonator P12 is connected to the connection point between the series arm resonator S12 and the series arm resonator S13. The other end of the parallel arm resonator P11 and the other end of the parallel arm resonator P12 are connected to each other and to ground.

A parallel arm resonator P13 is connected between the connection point of the series arm resonator S13 and the series arm resonator S14 and the ground.

A parallel arm resonator P14 is connected between the connection point of the series arm resonator S14 and the series arm resonator S15 and the ground.

A cancellation circuit 6 and a capacitor C0 are connected in parallel to the series-connected series arm resonators S11, S12, S13, S14, and S15.

A capacitor C1 is connected in parallel with the series arm resonator S14.

A receiving side filter 20 is formed between the antenna side terminal Ant and the receiving side terminal Rx. The receiving filter 20 is a ladder type filter including series arm resonators S21, S22, parallel arm resonators P21, P22, P23, and a double mode SAW filter 7.

In the reception filter 20, a series arm resonator S21, a double mode SAW filter 7, and a series arm resonator S22 are connected in this order between the antenna side terminal Ant and the reception side terminal Rx.

A parallel arm resonator P21 is connected between the connection point of the series arm resonator S21 and the double mode SAW filter 7 and the ground.

A parallel arm resonator P22 is connected between the connection point between the double mode SAW filter 7 and the series arm resonator S22 and the ground.

A parallel arm resonator P23 is connected between the connection point between the series arm resonator S22 and the receiving terminal Rx and the ground.

Note that in the elastic wave filter 100, inductors may be intentionally formed at predetermined locations, or inductors may be formed floatingly at predetermined locations by wiring, but these are not shown in FIG. The inductor is not shown.

As described above, the elastic wave filter 100 includes a duplexer including two acoustic wave filters, the transmitter filter 10 and the receiver filter 20, which are made of the equivalent circuit of FIG. 2, on the piezoelectric substrate 1. ing.

The piezoelectric substrate 1 may itself be made of a piezoelectric material. Alternatively, the piezoelectric substrate 1 may be one in which a film (layer) of a piezoelectric material is formed on a non-piezoelectric base. Although the type of piezoelectric material is arbitrary, for example, LiNbO ₃ , LiTaO ₃ , etc. can be used.

As shown in FIG. 1, on the main surface of the substrate 1, the series arm resonators S11 to S15 of the transmitting side filter 10, the parallel arm resonators P11 to P14, the series arm resonators S21 and S22 of the transmitting side filter 10, and the parallel arm Resonators P21 to P23 are formed.

The series arm resonators S11 to S15, S21, S22 and the parallel arm resonators P11 to P14, P21 to P23 will be explained by taking the series arm resonator S13 as an example, with reference to the main part plan view of the elastic wave filter 100 in FIG. do. The other resonators have the same basic structure as the series arm resonator S13 except for the dimensions and the number of electrode fingers.

The resonator (series arm resonator S13) includes an IDT electrode 30. The IDT electrode 30 includes a plurality of first IDT electrode fingers 31 and a plurality of second IDT electrode fingers 32. The plurality of first IDT electrode fingers 31 and the plurality of second IDT electrode fingers 32 are arranged so as to be engaged with each other. In this embodiment, the first IDT electrode finger 31 and the second IDT electrode finger 32 each extend in the vertical direction Y of the acoustic wave filter 100. A plurality of first IDT electrode fingers 31 are connected to a first bus bar 33. A plurality of second IDT electrode fingers 32 are connected to a second bus bar 34.

The resonator (series arm resonator S13) includes a first reflector electrode 40 and a second reflector electrode 50 on both sides of the IDT electrode 30 in the lateral direction X of the acoustic wave filter 100. The first reflector electrode 40 includes a plurality of reflector electrode fingers 41 . The reflector electrode fingers 41 extend in the vertical direction Y of the acoustic wave filter 100. Each of the plurality of reflector electrode fingers 41 has one end connected to the third bus bar 42 and the other end connected to the fourth bus bar 43. Similarly, the second reflector electrode 50 includes a plurality of reflector electrode fingers 51. The reflector electrode fingers 51 extend in the vertical direction Y of the acoustic wave filter 100. Each of the plurality of reflector electrode fingers 51 has one end connected to the fifth bus bar 52 and the other end connected to the sixth bus bar 53.

The materials of the series arm resonators S11 to S15, S21, S22 and the parallel arm resonators P11 to P14, P21 to P23 are arbitrary, but for example, Pt, Au, Ag, Cu, Ni, W, Ta, Fe, Cr. , Al, and Pd, or an alloy containing one or more of these metals. The series arm resonators S11 to S15, S21, and S22 and the parallel arm resonators P11 to P14 and P21 to P23 may be formed into a multilayer structure using a plurality of types of the above metals or alloys.

As shown in FIG. 1, capacitors C0 and C1, a cancellation circuit 6, and a double mode SAW filter 7 are formed on the main surface of a substrate 1. These structures and materials are arbitrary.

A wiring 8 is formed on the main surface of the substrate 1. The material and structure of the wiring 8 are arbitrary. In this embodiment, the wiring 8 includes a first electrode layer group in which NiCr, Pt, Ti, AlCu, and Ti are laminated in order from the bottom, and a first electrode layer group in which Ti, AlCu, Ti, Pt, and Ti are laminated in order from the bottom. It includes two electrode layer groups. The wiring 8 may include a second electrode layer group overlaid on a first electrode layer group. In this case, the Ti layer at the boundary between the two may be shared. Moreover, the wiring 8 may be formed in either the first electrode layer group or the second electrode layer group. Further, the wiring 8 may include a third electrode layer group in addition to the first electrode layer group and the second electrode layer group. In each of the first electrode layer group and the second electrode layer group, the number of constituent layers can be increased or decreased (they may be a single layer consisting of one layer), and the material of the constituent layers can be changed.

A bump 2 serving as the antenna terminal Ant, a bump 3 serving as the transmitting terminal Tx, a bump 4 serving as the receiving terminal Rx, and a plurality of bumps 5 serving as the ground terminal G are formed at predetermined locations on the wiring 8. ing. The portion of the wiring 8 where the bumps 2 to 5 are formed can also be called a bump pad. Although the bumps 2 to 5 can be made of any material, they can be made of, for example, solder or Au. Note that the ground terminal G is a terminal that is set to a reference potential (eg, ground potential) when the elastic wave filter 100 is used. The reference potential is not limited to the ground potential.

The wiring 8 connects the series arm resonators S11 to S15, S21, S22, the parallel arm resonators P11 to P14, P21 to P23, the capacitors C0 and C1, the cancellation circuit 6, the double mode SAW filter 7, and the bumps 2 to 5. , the necessary electrical connections have been made.

In the elastic wave filter 100 of this embodiment, as shown in FIGS. 1 and 3, the first reflector electrode 40 of the series arm resonator S13 of the transmitting side filter 10 is connected to the ground terminal G by the first wiring 9. Connected to bump 5. The first wiring 9 is a type of wiring 8, and is provided especially for heat radiation. Specifically, the heat generated in the IDT electrode 30 of the series arm resonator S13 is transmitted through the first reflector electrode 40 and further through the first wiring 9, and is efficiently transferred to the bump 5, which is the ground terminal G. It dissipates heat.

In this embodiment, only the first reflector electrode 40 is connected to the bump 5, which is the ground terminal G, by the first wiring 9, but the second reflector electrode 50 is also connected to the ground by another first wiring 9. It may be connected to the bump 5 which is the terminal G. In this case, the heat generated in the IDT electrode 30 can be radiated more efficiently.

The first wiring 9 includes at least two linear portions arranged side by side. The first wiring 9 includes at least one folded portion that folds back the two linear portions.

In this embodiment, as shown in FIG. 3, the first wiring 9 includes seven

linear portions

91a, 91b, 91c, 91d, 91e, 91f, and 91g arranged side by side. However, the number of linear parts is not limited to seven, and can be increased or decreased from seven. The linear portions 91a to 91g each extend in the vertical direction Y of the elastic wave filter 100.

Although the shape of the linear portions is arbitrary, in this embodiment, the linear portions 91a to 91g are each straight. However, the linear portions 91a to 91g may be curved lines instead of straight lines.

The first reflector electrode 40 is connected to the linear portion 91a. The linear portion 91a and the linear portion 91b are connected by a folded portion 92a. The linear portion 91b and the linear portion 91c are connected by a folded portion 92b. The linear portion 91c and the linear portion 91d are connected by a folded portion 92c. The linear portion 91d and the linear portion 91e are connected by a folded portion 92d. The linear portion 91e and the linear portion 91f are connected by a folded portion 92e. The linear portion 91f and the linear portion 91g are connected by a folded portion 92f. The linear portion 91g is connected to the bump 5, which is the ground terminal G.

In this embodiment, the linear parts 91a to 91g folded back at the folded parts 92a to 92f are arranged parallel to each other, but the linear parts folded back at the folded parts are arranged at an angle to each other. It's okay.

The reason why the first wiring 9 is configured to include seven linear parts 91a to 91g and six folded parts 92a to 92f that connect them is because the length of the first wiring 9 is increased and the first This is to increase the impedance of the wiring 9.

That is, if the reflector electrode is connected to a bump at a reference potential (for example, ground potential) by a short wiring, the reflector electrode will also be at the reference potential or a potential close to the reference potential. Then, as described above, the potential difference between the IDT electrode and the reflector electrode increases, unnecessary capacitance is generated between the IDT electrode and the reflector electrode, and the characteristics of the acoustic wave filter deteriorate.

Therefore, the elastic wave filter 100 includes the first reflector electrode 40 and the bump 5 which is the ground terminal G, seven linear parts 91a to 91g and six folded parts 92a to 92f, and has a long length and impedance. By connecting with the first wiring 9 having a large value, the potential difference between the IDT electrode 30 and the first reflector electrode 40 is reduced, and the generation of unnecessary capacitance between the IDT electrode 30 and the first reflector electrode 40 is suppressed. .

The elastic wave filter 100 includes a meander wiring region 60 on the substrate 1 in which the first wiring 9 is formed in a meander shape, since the first wiring 9 includes a plurality of folded parts 92a to 92f.　

As shown in FIG. 3, in this embodiment, the meander wiring area 60 is rectangular. The outer edge of the meander wiring region 60 includes a first side 61, a second side 62, a third side 63, and a fourth side 64, which are connected at right angles in this order. The first side 61 and the third side 63 extend in the direction in which the first IDT electrode finger 31 and the second IDT electrode finger 32 of the IDT electrode 30 extend. That is, the first side 61 and the third side 63 are arranged in the vertical direction Y of the elastic wave filter 100. The first side 61 is arranged closer to the first reflector electrode 40 than the third side 63.

In this embodiment, a linear portion 91a is arranged inside the first side of the meander wiring region 60, folded

portions

92a, 92c, and 92e are arranged side by side inside the second side 62, and A linear portion 91g is arranged on the inner side, and folded

portions

92b, 92d, and 92f are arranged side by side on the inner side of the fourth side 64.

Although the material of the first wiring 9 is arbitrary, it is preferable to use a material with as high thermal conductivity as possible. In this embodiment, the first wiring 9 includes a first electrode layer group in which NiCr, Pt, Ti, AlCu, and Ti are laminated in order from the bottom, and a Ti layer formed on the first electrode layer group from the bottom. , AlCu, Ti, Pt, and Ti are laminated in this order. The Ti layer at the boundary between the two may be shared.

In this embodiment, the direction in which the reflector electrode fingers 41 of the first reflector electrode 40 extend and the direction in which the linear portions 91a to 91g of the first wiring 9 extend are both arranged in the vertical direction Y of the acoustic wave filter 100. has been done. Therefore, in this embodiment, the linear portions 91a to 91g of the first wiring 9 can be used (aided) as reflector electrode fingers of the reflector electrode. In this case, the number of reflector electrode fingers 41 of the first reflector electrode 40 may be reduced. Note that when the linear portions 91a to 91g of the first wiring 9 are used as reflector electrode fingers of the reflector electrode, the pitch between the linear portions 91a to 91g of the first wiring 9 and the first reflector It is preferable that the pitch between the electrode 40 and the linear portion 91a be the same as the pitch between the reflector electrode fingers 41 of the first reflector electrode 40.

In this embodiment, since the region where the first reflector electrode 40 and the linear portion 91a of the first wiring 9 face each other is long, the heat of the first reflector electrode 40 is transferred via the first wiring 9. Heat can be efficiently radiated to the bumps 5.

In the meander wiring region 60, when the part where the first wiring 9 is provided is defined as a wiring pattern part, and the part where the first wiring 9 is not provided is defined as a non-wiring pattern part, the total area of the wiring pattern part and the non-wiring pattern part are The ratio to the total area of the pattern portion is arbitrary. However, when the area of the meander wiring region 60 is constant, the heat dissipation efficiency by the first wiring 9 improves as the total area of the wiring pattern portion is made larger than the total area of the non-wiring pattern portion. Further, when the area of the meander wiring region 60 and the interval between the wiring (linear parts) are constant, the smaller the total area of the wiring pattern part is than the total area of the non-wiring pattern part, the more the first Since the width of the wiring 9 can be reduced and the length of the first wiring 9 can be increased, the impedance of the first wiring 9 can be increased, and the impedance between the IDT electrode 30 and the first reflector electrode 40 can be increased. The generation of unnecessary capacity can be further suppressed.

In the elastic wave filter 100 of this embodiment, the first reflector electrode 40 of the series arm resonator S13 of the transmitting filter 10 is connected to the bump 5, which is the ground terminal G, via the first wiring 9. However, which reflector electrode of which resonator is connected to the bump by the first wiring is arbitrary, and reflector electrodes of other resonators may be connected to the bump. Further, reflector electrodes of a plurality of resonators may be connected to the bump. Furthermore, instead of connecting one reflector electrode of the resonator to the bump, both reflector electrodes may be connected to the bump.

However, regarding which resonator's reflector electrode should be connected to the bump by the first wiring, in the acoustic wave filter, the reflector electrode of the resonator whose IDT electrode generates a large amount of heat should be connected to the bump by the first wiring. preferable. For example, if the elastic wave filter is a ladder type filter, the series arm resonator with the lowest anti-resonance frequency among the series arm resonators, and the parallel arm resonator with the highest resonant frequency among the parallel arm resonators, Preferably, the reflector electrode is connected to the bump by a first wiring. In addition, in a series arm resonator in which the pitch of the IDT electrode fingers of the IDT electrode is the largest among the series arm resonators, and in a parallel arm resonator in which the pitch of the IDT electrode fingers of the IDT electrode is the smallest among the parallel arm resonators, Preferably, the reflector electrode is connected to the bump by a first wiring.

Further configurations may be added to the elastic wave filter 100 of this embodiment. For example, on the board 1, series arm resonators S11 to S15, S21, S22, parallel arm resonators P11 to P14, P21 to P23, capacitors C0 and C1, canceling circuit 6, double mode SAW filter 7, wiring 8, first A single dielectric layer (insulator layer) or multiple dielectric layers may be formed on the portion where the wiring 9 is formed. Moreover, the wiring 8 may be further formed between the dielectric layers or on the dielectric layer.

(Experiment 1)
In order to confirm the effectiveness of the present invention, the following Experiment 1 was conducted.

As shown in FIG. 4, as an example, an elastic wave filter 100 of this embodiment was manufactured. In the embodiment, the first reflector electrode 40 is connected to the bump 5, which is the ground terminal G, via the first wiring 9.

Comparative Example 1 was produced. In Comparative Example 1, a part of the configuration of the elastic wave filter 100 is changed, the first wiring 9 is omitted, and the first reflector electrode 40 is not connected to the bump 5, which is the ground terminal G.

Comparative Example 2 was produced. In Comparative Example 2, a part of the configuration of the elastic wave filter 100 was also changed, the first wiring 9 was omitted, and a planar wiring 99 having a large rectangular area was provided instead. Then, the first reflector electrode 40 was connected to the bump 5, which is the ground terminal G, by a planar wiring 99.

Comparative Example 2, in which the first reflector electrode 40 was connected to the bump 5, which is the ground terminal G, by the planar wiring 99 was the most excellent in the ability to radiate the heat generated in the IDT electrode 30. The second example is the one in which the first reflector electrode 40 is connected to the bump 5, which is the ground terminal G, by the first wiring 9. Comparative example 1, in which the first reflector electrode 40 and the bump 5 serving as the ground terminal G are not connected, has the lowest ability to dissipate the heat generated in the IDT electrode 30.

For each of the elastic wave filters of Example, Comparative Example 1, and Comparative Example 2, the reflection characteristics of the transmitting filter 10 were measured.

Figure 5 shows the measurement results. In FIG. 5, the solid line graph is the example, the one-dot chain line graph is Comparative Example 1, and the two-dot chain line graph is Comparative Example 2.

As can be seen from FIG. 5, the reflection characteristics of Comparative Example 1 are the best (reflection is small). This is because the first reflector electrode 40 was not connected to the bump 5, which is the ground terminal G, so no potential difference (or only a very small potential difference) occurred between the IDT electrode 30 and the first reflector electrode 40. This is considered to be because no unnecessary capacitance was generated between the IDT electrode 30 and the first reflector electrode 40 (or only a very small unnecessary capacitance was generated).

On the other hand, in Examples and Comparative Example 2, the reflection characteristics are lower than in Comparative Example 1. However, the degree of decrease in reflection characteristics is large in Comparative Example 1 and small in Examples. In Comparative Example 1, the reflection characteristics were significantly reduced because the first reflector electrode 40 and the bump 5, which is the ground terminal G, were connected by a planar wiring 99 whose impedance was not large. This is considered to be because a large potential difference was generated between the IDT electrode 30 and the first reflector electrode 40, and a large unnecessary capacitance was generated between the IDT electrode 30 and the first reflector electrode 40. On the other hand, in the example, the decline in reflection characteristics was small because the first reflector electrode 40 and the bump 5, which is the ground terminal G, were connected by the first wiring 9 having a large impedance. This is considered to be because the generation of a potential difference between the IDT electrode 30 and the first reflector electrode 40 was suppressed, and the generation of unnecessary capacitance between the IDT electrode 30 and the first reflector electrode 40 was suppressed.

From the above, the present invention is effective in efficiently dissipating the heat generated in the IDT electrode to the bump, while suppressing the generation of unnecessary capacitance between the IDT electrode and the reflector electrode, and suppressing the deterioration of characteristics. It was confirmed that it is effective.

[Second embodiment]
FIG. 6 shows an elastic wave filter 200 according to the second embodiment. However, FIG. 6 is a plan view of essential parts of the elastic wave filter 200.

The elastic wave filter 200 according to the second embodiment has a part of the configuration of the elastic wave filter 100 according to the first embodiment. Specifically, in the elastic wave filter 100, the direction in which the

linear portions

91a, 91b, 91c, 91d, 91e, 91f, and 91g of the first wiring 9 extend is the longitudinal direction Y of the elastic wave filter 100. In the elastic wave filter 100, the direction in which the

linear portions

94a, 94b, 94c, 94d, 94e, 94f, 94g, 94h, and 94i of the first wiring 29 extend is the lateral direction X of the elastic wave filter 100. Then, the linear portions 94a to 94i were connected by folded portions 95a to 95h. However, the shape and size of the meander wiring region 60 are the same as those of the elastic wave filter 100, and instead, the lengths of the linear portions 94a to 94i are shortened compared to the elastic wave filter 100, and the linear portion 94a is .about.94i and the number of folded portions 95a to 95h were increased.

In the elastic wave filter 200, the folded

portions

95b, 95d, 95f, and 95h are arranged side by side on the inside of the first side of the meander wiring region 60, the linear portion 94i is arranged on the inside of the second side 62, and the folded portions 94i are arranged on the inside of the second side 62, The folded

parts

95a, 95c, 95e, and 95g are arranged side by side inside the fourth side 63, and the linear part 94a is arranged inside the fourth side 64.

The elastic wave filter 200 has a feature that, compared to the elastic wave filter 100, unnecessary capacitance (stray capacitance) generated between the first reflector electrode 40 and the bump 5 is reduced. The unnecessary capacitance generated between the first reflector electrode 40 and the bump 5 is made up of the unnecessary capacitance generated between each linear portion of the first wiring connected in series. The unnecessary capacitance generated between the elastic wave filter and the elastic wave filter 5 is also a factor that deteriorates or fluctuates the characteristics of the elastic wave filter, so it is preferable that the unnecessary capacitance is small.

In the elastic wave filter 200, the lengths of the linear parts 94a to 94i are shorter than the lengths of the linear parts 91a to 91g of the elastic wave filter 100. Further, in the elastic wave filter 200, the number of linear parts 94a to 94i folded back by the folding parts 95a to 95h is greater than the number of linear parts 91a to 91g folded back by the folding parts 92a to 92f of the elastic wave filter 100. There are also many. Therefore, the unnecessary capacitance generated between the first reflector electrode 40 and the bump 5, in which the unnecessary capacitance generated between each linear portion is connected in series, is smaller in the elastic wave filter 200 than in the elastic wave filter 100. small. Therefore, in the elastic wave filter 200, as compared to the elastic wave filter 100, deterioration and fluctuation in characteristics due to unnecessary capacitance generated between the first reflector electrode 40 and the bump 5 are suppressed.

[Third embodiment]
FIG. 7 shows an elastic wave filter 300 according to a third embodiment. However, FIG. 7 is a plan view of essential parts of the elastic wave filter 300.

The elastic wave filter 300 according to the third embodiment has a new configuration added to the elastic wave filter 100 according to the first embodiment. Specifically, in the elastic wave filter 100, only the first reflector electrode 40 was connected to the bump 5, which is the ground terminal G, by the first wiring 9. On the other hand, in the elastic wave filter 300, the second reflector electrode 50 is also connected to the bump 5, which is another ground terminal G, through another first wiring 9.

Compared to the elastic wave filter 100, the elastic wave filter 300 has improved efficiency in dissipating heat generated in the IDT 30.

[Fourth embodiment]
FIG. 8 shows an elastic wave filter 400 according to a fourth embodiment. However, FIG. 8 is a plan view of essential parts of the elastic wave filter 400.

The elastic wave filter 400 according to the fourth embodiment has a part of the configuration of the elastic wave filter 100 according to the first embodiment. Specifically, the elastic wave filter 400 includes a convex portion 33a formed on the first bus bar 33 of the IDT electrode 30, a convex portion 34a formed on the second bus bar 34, and a convex portion 34a formed on the third bus bar 42 of the first reflector electrode 40. A recess 42a was formed, a recess 43a was formed in the fourth bus bar 43, the protrusion 33a and the recess 42a were fitted with a space between them, and the protrusion 34a and the recess 43a were fitted with a space between them.

Note that instead of the above configuration, the first bus bar 33 and the second bus bar 34 are each provided with a concave portion, the third bus bar 42 and the fourth bus bar 43 are each provided with a convex portion, and these concave portions and convex portions are connected. They may be fitted together.

Compared to the acoustic wave filter 100, the acoustic wave filter 400 has improved efficiency in dissipating heat from the IDT electrode 30 to the first reflector electrode 40, and has improved overall efficiency in dissipating heat generated in the IDT electrode 30. , has further improved.

[Fifth embodiment]
FIG. 9 shows an elastic wave filter 500 according to the fifth embodiment. However, FIG. 9 is a plan view of essential parts of the elastic wave filter 500.

The elastic wave filter 500 according to the fifth embodiment has a new configuration added to the elastic wave filter 100 according to the first embodiment. Specifically, in the elastic wave filter 500, a protrusion 33a is formed on the first bus bar 33 of the IDT electrode 30, and a protrusion 34a is formed on the second bus bar 34. Then, the convex portion 33a is stacked on the third bus bar 42 of the first reflector electrode 40 with an insulating layer 81 interposed therebetween, and the convex portion 34a is stacked on the third bus bar 42 of the first reflector electrode 40 with an insulating layer 81 interposed therebetween. It was stacked on the fourth bus bar 43 of.

Compared to the elastic wave filter 100, the acoustic wave filter 500 has improved efficiency in dissipating heat from the IDT electrode 30 to the first reflector electrode 40, and has improved overall efficiency in dissipating heat generated in the IDT electrode 30. , has further improved.

[Sixth embodiment]
FIG. 10 shows an elastic wave filter 600 according to the sixth embodiment. However, FIG. 10 is a plan view of essential parts of the elastic wave filter 600.

The elastic wave filter 600 according to the sixth embodiment has a new configuration added to the elastic wave filter 100 according to the first embodiment. Specifically, in the acoustic wave filter 600, a rectangular planar wiring 85 having a large area is first provided in a region of the substrate 1 where the first wiring 9 is to be formed, and an insulating layer 86 is provided thereon. Then, the first wiring 9 was formed on the insulating layer 86. The planar wiring 85 is not connected to anything and is a floating electrode.

Compared to the elastic wave filter 100, the elastic wave filter 600 has improved efficiency in dissipating heat from the first reflector electrode 40, and further improves overall efficiency in dissipating heat generated in the IDT electrode 30. ing.

[Seventh embodiment]
FIG. 11 shows an elastic wave filter 700 according to a seventh embodiment. However, FIG. 11 is an explanatory diagram (a sectional view of a main part) of the elastic wave filter 700.

The elastic wave filter 700 according to the seventh embodiment has a new configuration added to the elastic wave filter 100 according to the first embodiment. Specifically, the elastic wave filter 700 includes the series arm resonators S11 to S15, S21, S22, the parallel arm resonators P11 to P14, P21 to P23, the capacitors C0 and C1, the cancellation circuit 6, A first dielectric layer (insulator layer) 71 and a second dielectric layer (insulator layer) are formed on a predetermined portion of the substrate 1 on which the double mode SAW filter 7, wiring 8, first wiring 9, etc. are formed. 72 was formed. Further, a wiring 8 was further formed between the first dielectric layer 71 and the second dielectric layer 72.

Although the first dielectric layer 71 and the second dielectric layer 72 may be made of any material, for example, SiO ₂ can be used.

In the acoustic wave filter 700, the total thickness dimension D1 of the first dielectric layer 71 and the second dielectric layer 72 in the region forming the resonator is set to The total thickness dimension D2 of the two dielectric layers 72 is made smaller. The reason why the total thickness dimension D1 of the first dielectric layer 71 and the second dielectric layer 72 in the region forming the resonator is reduced is because the first dielectric layer 71 and the second dielectric layer 72 This is to prevent the excitation of the IDT electrode 30 from being suppressed. The total thickness dimension D2 of the first dielectric layer 71 and the second dielectric layer 72 in other areas was increased by using (via) the first dielectric layer 71 and the second dielectric layer 72. This is to radiate heat generated in the IDT electrode 30 to the outside.

The heat dissipation effect of the elastic wave filter 700 is further improved by forming the first dielectric layer 71 and the second dielectric layer 72. Furthermore, by forming the first dielectric layer 71 and the second dielectric layer 72, the elastic wave filter 700 includes series arm resonators S11 to S15, S21, S22, parallel arm resonators P11 to P14, P21 to P23. , capacitors C0, C1, cancel circuit 6, double mode SAW filter 7, wiring 8, first wiring 9, etc. are protected from the outside. In addition, in the acoustic wave filter 700, by forming the first dielectric layer 71 and the second dielectric layer 72, three-dimensional wiring of the wiring 8 is possible.

[Eighth embodiment]
FIG. 12 shows an elastic wave filter 800 according to the eighth embodiment. However, FIG. 12 is a plan view of essential parts of the elastic wave filter 800.

The elastic wave filter 800 according to the eighth embodiment has a new configuration added to the elastic wave filter 100 according to the first embodiment. Specifically, in the elastic wave filter 800, a wiring missing portion 93 is formed in the first wiring 9 within the meander wiring region 60.

The elastic wave filter 800 can make the potential difference between the IDT electrode 30 and the first reflector electrode 40 smaller than the elastic wave filter 100, and can reduce unnecessary capacitance between the IDT electrode 30 and the first reflector electrode 40. The occurrence can be further suppressed. Note that the interval between the wiring missing portions 93 is preferably smaller than the interval between the IDT electrode 30 and the first reflector electrode 40 in order to maintain good heat dissipation.

The elastic wave filters 100, 200, 300, 400, 500, 600, 700, and 800 according to the embodiments have been described above. However, the present invention is not limited to the content described above, and various changes can be made in accordance with the spirit of the invention.

For example, in the above embodiment, a duplexer including two elastic wave filters is shown as the elastic wave filter, but the elastic wave filter is not limited to a duplexer, and may be a single elastic wave filter. Further, in the above embodiment, the elastic wave filter is a ladder type filter, but the elastic wave filter is not limited to a ladder type filter.

Further, the shape and size of the meander wiring region shown in the above embodiments are merely examples, and the shape and size can be changed as appropriate.

The elastic wave filter according to one embodiment of the present invention is as described in the "Means for Solving the Problems" section.

In this elastic wave filter, it is also preferable that the first wiring includes at least two folded portions, and that a rectangular meander wiring region is formed on the substrate by the first wiring. In this case, it is possible to increase the length of the first wiring and increase the impedance of the first wiring, so it is possible to further suppress the generation of unnecessary capacitance between the IDT electrode and the reflector electrode. It is possible to do so.

The meander wiring area consists of a wiring pattern portion where the first wiring is provided and a non-wiring pattern portion where the first wiring is not provided, and the total area of the wiring pattern portion is larger than the total area of the non-wiring pattern portion. It is also preferable that it is large. In this case, when the area of the meander wiring region is constant, the larger the total area of the wiring pattern portion is than the total area of the non-wiring pattern portion, the more the heat dissipation efficiency by the first wiring improves.

The meandering wiring region consists of a wiring pattern portion provided with wiring and a non-wiring pattern portion not provided with wiring, and it is also preferable that the total area of the wiring pattern portion is smaller than the total area of the non-wiring pattern portion. . In this case, when the area of the meander wiring region and the interval between the wiring (linear parts) are constant, the smaller the total area of the wiring pattern part is than the total area of the non-wiring pattern part, the more Since the width of one wiring can be reduced and the length of the first wiring can be increased, the impedance of the first wiring can be increased, and unnecessary capacitance between the IDT electrode and the reflector electrode can be reduced. This can be further suppressed.

The outer edge of the meander wiring area has a first side, a second side, a third side, and a fourth side that are connected at right angles in order, and the first side and the third side extend in the direction in which the IDT electrode finger extends, and the first side are arranged closer to the reflector electrode than the third side, a plurality of the folded parts are arranged side by side inside the second side, and another plurality of folded parts are arranged side by side inside the fourth side. It is also preferable that In this case, since the direction in which the reflector electrode fingers of the reflector electrode extend and the direction in which the linear portions of the first wiring extend are the same, the linear portions of the first wiring are used as the reflector electrode fingers of the reflector electrode. )can do. In this case, it is also preferable that the pitch between the reflector electrode fingers is equal to the pitch between the linear parts of the first wiring.

The outer edge of the meander wiring area has a first side, a second side, a third side, and a fourth side that are connected at right angles in order, and the first side and the third side extend in the direction in which the IDT electrode finger extends, and the first side is arranged closer to the reflector electrode than the third side, a plurality of folded parts are arranged side by side inside the first side, and another plurality of folded parts are arranged side by side inside the fourth side. is also preferable. If the lengths of the first side and third side are longer than the lengths of the second side and fourth side, the above arrangement can shorten the length of each linear part, and the folded part Since the number of folded linear parts can be increased, unnecessary capacitance generated between the reflector electrode and the bump can be reduced, and deterioration and fluctuation of characteristics due to this unnecessary capacitance can be suppressed. In this case, it is also preferable that the pitch between the reflector electrode fingers is equal to the pitch between the linear parts of the first wiring.

The IDT electrode includes a first bus bar and a second bus bar, the reflector electrode includes a third bus bar and a fourth bus bar, and the first bus bar and the third bus bar fit into each other with a space between them. It is also preferable that the second bus bar and the fourth bus bar are arranged so as to fit into each other with a space between them. In this case, the efficiency of dissipating the heat of the IDT electrode to the reflector electrode is improved, so the overall efficiency of dissipating the heat generated in the IDT electrode is further improved.

The IDT electrode includes a first bus bar and a second bus bar, the reflector electrode includes a third bus bar and a fourth bus bar, and the first bus bar and the third bus bar are partially laminated with an insulating layer interposed therebetween. It is also preferable that the second bus bar and the fourth bus bar are arranged so as to be partially laminated with an insulating layer interposed therebetween. In this case, the efficiency of dissipating the heat of the IDT electrode to the reflector electrode is improved, so the overall efficiency of dissipating the heat generated in the IDT electrode is further improved.

It is also preferable that a wiring missing part where the wiring pattern is missing is formed in the middle of the first wiring. In this case, the potential difference between the IDT electrode and the reflector electrode can be made smaller, and the generation of unnecessary capacitance between the IDT electrode and the reflector electrode can be further suppressed. Note that, in order to maintain good heat dissipation, the interval between the wiring missing parts is preferably smaller than the interval between the IDT electrode and the reflector electrode.

A ladder type filter is configured by a plurality of resonators, and the ladder type filter includes a series arm resonator and a parallel arm resonator. , is also preferably connected to the bump by the first wiring. In this case, the heat generated in the IDT electrode of the resonator, which generates a large amount of heat, can be efficiently radiated.

A ladder type filter is configured by a plurality of resonators, and the ladder type filter includes a series arm resonator and a parallel arm resonator, and the pitch between the IDT electrode fingers of the IDT electrodes is the largest among the series arm resonators. It is also preferable that the reflector electrode of the series arm resonator is connected to the bump by the first wiring. In this case, the heat generated in the IDT electrode of the resonator, which generates a large amount of heat, can be efficiently radiated.

A ladder type filter is configured by a plurality of resonators, and the ladder type filter includes a series arm resonator and a parallel arm resonator, and in the parallel arm resonator, the reflector electrode of the parallel arm resonator having the highest resonance frequency is It is also preferable that the first wiring be connected to the bump. In this case, the heat generated in the IDT electrode of the resonator, which generates a large amount of heat, can be efficiently radiated.

A ladder type filter is configured by a plurality of resonators, and the ladder type filter includes a series arm resonator and a parallel arm resonator, and the pitch between the IDT electrode fingers of the IDT electrodes is the smallest in the parallel arm resonator. It is also preferable that the reflector electrode of the parallel arm resonator is connected to the bump by the first wiring. In this case, the heat generated in the IDT electrode of the resonator, which generates a large amount of heat, can be efficiently radiated.

1... Board 2... Bump (antenna side terminal Ant)
3... Bump (transmission side terminal Tx)
4... Bump (receiving side terminal Rx)
5... Bump (ground terminal G)
8... Wiring 9... First wiring 91a to 91g, 94a to 94i... Linear parts 92a to 92f, 95a to 95h... Turned part 93... Wiring missing part 10... Transmission side Filter 20...Reception side filter 30...IDT electrode 31...First IDT electrode finger 32...Second IDT electrode finger 33...First bus bar 34...Second bus bar 40...First Reflector electrode 41... Reflector electrode finger 42... Third bus bar 43... Fourth bus bar 50... Second reflector electrode 51... Reflector electrode finger 52... Fifth bus bar 53... 6 bus bar 60...meander wiring area 61...first side 62...second side 63...third side 64...fourth side 71...first dielectric layer 72... Second dielectric layers 81, 86... Insulating layer 85... Planar wiring X... Horizontal direction of elastic wave filter Y... Vertical direction of elastic wave filter

Claims

A substrate and
at least one resonator formed on the substrate;
a plurality of bumps formed on the substrate;
An acoustic wave filter comprising a plurality of wirings formed on the substrate,
The resonator includes an IDT electrode having IDT electrode fingers, and a pair of reflector electrodes formed on both sides of the IDT electrode in a direction perpendicular to a direction in which the IDT electrode fingers extend,
The reflector electrode includes a plurality of reflector electrode fingers,
At least one of the resonators has at least one of the reflector electrodes connected to the bump by a first wiring,
The first wiring includes at least two linear parts,
The first wiring includes at least one folding portion that folds back the two linear portions arranged side by side.
elastic wave filter.
The first wiring includes at least two of the folded parts,
A rectangular meander wiring area is formed on the substrate by the first wiring,
The elastic wave filter according to claim 1.
The meander wiring area includes a wiring pattern portion where the first wiring is provided and a non-wiring pattern portion where the first wiring is not provided,
The total area of the wiring pattern portion is larger than the total area of the non-wiring pattern portion.
The elastic wave filter according to claim 2.
The meander wiring area includes a wiring pattern portion where the wiring is provided and a non-wiring pattern portion where the wiring is not provided,
The total area of the wiring pattern portion is smaller than the total area of the non-wiring pattern portion.
The elastic wave filter according to claim 2.
The outer edge of the meander wiring region includes a first side, a second side, a third side, and a fourth side that are connected at right angles in order,
The first side and the third side extend in a direction in which the IDT electrode finger extends,
the first side is arranged closer to the reflector electrode than the third side,
A plurality of the folded parts are arranged side by side inside the second side,
Another plurality of folded portions are arranged side by side inside the fourth side.
An elastic wave filter according to any one of claims 2 to 4.
The outer edge of the meander wiring region includes a first side, a second side, a third side, and a fourth side that are connected at right angles in order,
The first side and the third side extend in a direction in which the IDT electrode finger extends,
the first side is arranged closer to the reflector electrode than the third side,
A plurality of folded portions are arranged side by side inside the first side,
Another plurality of folded portions are arranged side by side inside the third side.
An elastic wave filter according to any one of claims 2 to 4.
the pitch between the reflector electrode fingers and the pitch between the linear portions of the first wiring are equal;
An elastic wave filter according to any one of claims 1 to 6.
The IDT electrode includes a first bus bar and a second bus bar,
The reflector electrode includes a third bus bar and a fourth bus bar,
the first bus bar and the third bus bar are arranged to fit into each other with a space between them;
The second bus bar and the fourth bus bar are arranged to fit into each other with a gap between them.
An elastic wave filter according to any one of claims 1 to 7.
The IDT electrode includes a first bus bar and a second bus bar,
The reflector electrode includes a third bus bar and a fourth bus bar,
the first bus bar and the third bus bar are arranged in a partially laminated manner with an insulating layer interposed therebetween;
The second bus bar and the fourth bus bar are arranged in a partially laminated manner with an insulating layer interposed therebetween.
An elastic wave filter according to any one of claims 1 to 7.
A wiring missing part where the wiring pattern is missing is formed in the middle of the first wiring,
An elastic wave filter according to any one of claims 1 to 9.
The distance between the missing wiring portions is smaller than the distance between the IDT electrode and the reflector electrode.
The elastic wave filter according to claim 10.
A ladder filter is configured by the plurality of resonators,
The ladder type filter includes a series arm resonator and a parallel arm resonator,
In the series arm resonator, the reflector electrode of the series arm resonator having the lowest anti-resonance frequency is connected to the bump by the first wiring.
An elastic wave filter according to any one of claims 1 to 11.
A ladder filter is configured by the plurality of resonators,
The ladder type filter includes a series arm resonator and a parallel arm resonator,
In the series arm resonator, the reflector electrode of the series arm resonator having the largest pitch between the IDT electrode fingers of the IDT electrodes is connected to the bump by the first wiring.
An elastic wave filter according to any one of claims 1 to 12.
A ladder filter is configured by the plurality of resonators,
The ladder type filter includes a series arm resonator and a parallel arm resonator,
In the parallel arm resonator, the reflector electrode of the parallel arm resonator having the highest resonance frequency is connected to the bump by the first wiring.
An elastic wave filter according to any one of claims 1 to 13.
A ladder filter is configured by the plurality of resonators,
The ladder type filter includes a series arm resonator and a parallel arm resonator,
In the parallel arm resonator, the reflector electrode of the parallel arm resonator having the smallest pitch between the IDT electrode fingers of the IDT electrode is connected to the bump by the first wiring.
An elastic wave filter according to any one of claims 1 to 14.