JP2007028594A - Multi-mode thin film acoustic wave resonator filter, ladder-type filter with same, duplexer, and communication apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a multi-mode thin film acoustic wave resonator filter improved in characteristics by efficiently utilizing generated charges. <P>SOLUTION: A multi-mode thin film acoustic wave resonator filter 100 comprises first and second input/output vibration portions 110 and 111 configured by holding a piezoelectric thin film 103 between first and second lower electrodes 104 and 106 and first and second upper electrodes 105 and 107, and a cavity 102 for commonly guaranteeing vibrations of the first and second input/output vibration portions 110 and 111 so as to couple the vibrations. The first and second input/output vibration portions 110 and 111 are located adjacently in contact with each other with a step therebetween, so that the first and second lower electrodes 104 and 106 are not electrically connected to each other and the first and second upper electrodes 105 and 107 are not electrically connected to each other. Insulators 108 and 109 are provided in the vicinity of the step. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a filter used in a high-frequency circuit such as a wireless device, and more particularly to a thin film elastic wave resonator filter using a plurality of modes, a duplexer including the filter, and a communication device.

  Conventional filters mounted on wireless communication devices such as mobile phones include dielectric filters, multilayer filters, and acoustic wave filters. Known acoustic wave filters include a crystal filter (MCF: monolithic crystal filter) using a plurality of modes of bulk waves, a surface acoustic wave filter (SAW filter), and the like. However, in recent years, filters are required to be further reduced in size, improved in performance, and higher in frequency. As a device for realizing this, a thin film acoustic wave resonator filter (FBAR filter) using a bulk wave of a piezoelectric thin film is used. Has been developed.

A conventional MCF (Patent Document 1) using a plurality of modes will be described. As this MCF, a configuration using an AT-cut quartz substrate is common. FIG. 26 is a diagram showing a configuration of a conventional MCF.
In this MCF, the AT-cut quartz crystal substrate 91 is photo-etched, whereby an ultrathin plate vibrating portion 92 and a thick annular portion 93 that holds the vibrating portion 92 are integrally formed. Electrodes 94 a and 94 b are arranged on the plane side of the AT-cut quartz substrate 91 with a gap g. An electrode 95 is attached to the entire surface of the AT-cut quartz substrate 91 on the recessed portion side by vapor deposition or the like. With this configuration, it is possible to use the first-order mode and the second-order mode generated as a result of acoustic coupling between the two pairs of electrodes 94a and 95 and the electrodes 94b and 95. The degree of coupling between the two modes, that is, the difference between the resonance frequencies of the two modes depends on the elastic constant of the AT-cut quartz substrate 91, the electrode shape, the electrode film thickness, and the two pairs of electrode gaps g. As the degree of coupling increases, a low-loss and broadband filter can be realized.

Further, an MCF (Patent Document 2) using another multiple mode will be described. FIG. 27 is a diagram showing another configuration of the conventional MCF.
The MCF includes three pairs of electrodes 82 and 83, electrodes 84 and 85, and electrodes 86 and 87 that face each other with a crystal substrate 81 (piezoelectric substrate) interposed therebetween. The pair of electrodes 84 and 85 in the center is input or output. Two pairs of electrodes 82 and 83 and electrodes 86 and 87, which are disposed on both sides of the electrodes 84 and 85 and have substantially the same shape as each other, are connected in parallel and serve as an output or an input. This MCF realizes high coupling in a plurality of modes by exciting the thickness vibration of the first mode and the thickness vibration of the third mode. Thereby, a broadband filter is realized.

  Furthermore, a filter using a thin film acoustic wave resonator that can realize a high frequency by using a piezoelectric thin film has also been proposed. FIG. 28 is a cross-sectional view of a conventional multimode thin film acoustic wave resonator filter using a thin film acoustic wave resonator and an ideal vibration mode distribution. Since the thin film acoustic wave resonator is configured by depositing a lower electrode, a piezoelectric thin film, an upper electrode, and the like on a substrate using means such as sputtering, the basic configuration is different from that of the MCF.

  In FIG. 28, the multimode thin film acoustic wave resonator filter 70 includes two pairs of electrodes 74 and 75 and electrodes 76 and 77 with a piezoelectric thin film 73 sandwiched on a substrate 71. As a result, two input / output vibration parts 78 and 79 are formed. In addition, a cavity 72 for ensuring the vibration of the two input / output vibration parts 78 and 79 is formed in the substrate 71 so as to be covered by the two input / output vibration parts 78 and 79. Note that an acoustic mirror layer may be used as means for securing vibration. As a result, the two input / output vibration parts 78 and 79 share the same cavity or acoustic mirror layer and function as a filter by utilizing the coupling between the primary mode and the secondary mode. Furthermore, by reducing the electrode shape, electrode film thickness, and the distance between the two input / output vibration parts (two pairs of electrodes), the degree of coupling between the two modes is improved, and low loss and wideband characteristics are achieved. It is known to get.

  FIG. 29 is a cross-sectional view of a conventional multimode thin film acoustic wave resonator filter that couples a first-order mode and a third-order mode, and an ideal vibration mode distribution. The multimode thin film elastic wave resonator filter 60 shown in FIG. 29 includes three input / output vibration parts 61 to 63. As a result, a filter using the coupling between the primary mode and the tertiary mode is realized. In addition, by reducing the electrode shape, electrode film thickness, and the distance between the three input / output vibration parts (two pairs of electrodes), the degree of coupling between the two modes is improved, and low loss and wideband characteristics are achieved. It is known to get.

The integral value of the vibration mode distribution curve shown in FIGS. 28 and 29 is substantially equivalent to the generated charge amount in the piezoelectric thin film. To provide a multimode thin film acoustic wave resonator filter having a low loss and a low band characteristic by using a generated charge in a piezoelectric thin film for vibration in two vibration parts, thereby increasing the coupling coefficient of each vibration part. Can do.
Japanese Patent Laid-Open No. 10-163804, FIG. Japanese Patent Laid-Open No. 10-145181, FIG.

  However, as shown in FIG. 28 and FIG. 29, the space between two or three input / output vibrating portions (two pairs of electrodes) could not be shortened to a certain distance or less due to the constraint conditions of electrode formation. For this reason, some of the generated charges are consumed at the non-electrode portion, loss occurs, and the filter characteristics are deteriorated.

  SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a multimode thin film acoustic wave resonator filter excellent in characteristics by efficiently using generated charges in an input / output vibration section. It is another object of the present invention to provide a ladder type filter, a duplexer, and a communication device using such a multimode thin film elastic wave resonator filter.

  The present invention is directed to a multimode thin film acoustic wave resonator filter. In order to achieve the above object, the multimode thin film acoustic wave resonator filter of the present invention includes a vibration part, a common vibration securing part, and at least one insulator.

  The vibration part was arranged adjacent to each other. A first input / output vibration unit configured by sandwiching a part of the piezoelectric body between the first lower electrode and the first upper electrode, and a part of the piezoelectric body including the second lower electrode and the second upper electrode It includes at least a second input / output vibration unit that is sandwiched between electrodes. The common vibration securing unit mounts the vibration unit and combines the plurality of vibrations by securing at least the vibration of the first input / output vibration unit and the vibration of the second input / output vibration unit in common. . The at least one insulator forms a step for electrically insulating at least one of the first lower electrode and the second lower electrode and at least one of the first upper electrode and the second upper electrode. Used for.

  Preferably, a first insulator thicker than the second lower electrode of the second input / output vibration part is formed under the first lower electrode of the first input / output vibration part, A second insulator thicker than the first upper electrode of the first input / output vibration part is formed on the second upper electrode of the input / output vibration part. It is desirable that the second insulator has a thickness that makes the resonance frequencies of the first and second input / output vibration parts substantially equal. The second insulator may be formed up to the upper surface of the first upper electrode. In this case, the second insulator only needs to have a mass that substantially equalizes the resonance frequencies of the first and second input / output vibration units.

Preferably, the first insulator is formed in a shape to be inserted between the second lower electrode and the piezoelectric body, and the second insulator is the first upper electrode and the piezoelectric body. It is formed in the shape inserted between. The first and second insulators only need to have masses that substantially equalize the resonance frequencies of the first and second input / output vibration units.
Preferably, the second insulator is formed up to the upper surface of the first upper electrode. The second insulator only needs to have a mass that substantially equalizes the resonance frequencies of the first and second input / output vibrating sections.

  The vibration unit is a third input / output vibration unit that is disposed adjacent to the first input / output vibration unit and includes a portion of the piezoelectric body sandwiched between the third lower electrode and the third upper electrode. May be further provided. In this case, the common vibration securing unit couples the plurality of vibrations by securing the vibrations of the first to third input / output vibration units in common, and the third upper electrode of the third input / output vibration unit. A third insulator thicker than the first upper electrode of the first input / output vibration unit is formed thereon, and the first insulator is formed from the third lower electrode of the third input / output vibration unit. Also thicken.

  The third insulator only needs to have a thickness that substantially equalizes the resonance frequencies of the first and third input / output vibrating portions. Further, the second and third insulators may be an integral layer formed up to the upper surface of the first upper electrode. The second and third insulators may have a mass that substantially equalizes the resonance frequencies of the first to third input / output vibration units.

  Further, the first lower electrode of the first input / output vibration unit and the second lower electrode of the second input / output vibration unit are electrically connected, and the second upper electrode of the second input / output vibration unit It is also possible to form an insulator thicker than the first upper electrode of the first input / output vibration unit. The insulator desirably has a thickness that substantially equalizes the resonance frequencies of the first and second input / output vibration portions.

Typically, the resonance vibration securing portion is a hollow portion formed in the substrate or an acoustic mirror layer having alternately a high acoustic impedance layer and a low acoustic impedance layer.
Further, the present invention may be a ladder type filter including the above-described multimode thin film acoustic wave resonator filter, a duplexer, or a communication device.

  As described above, according to the present invention, the generated charges can be used efficiently, and low loss and wideband characteristics can be realized. If such a multimode thin film acoustic wave resonator filter is used, the performance of the ladder filter, duplexer, and communication device is also improved.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
(First embodiment)
FIG. 1 is a cross-sectional view of a multimode thin film acoustic wave resonator filter 100 according to the first embodiment of the present invention. In FIG. 1, a multimode thin film acoustic wave resonator filter 100 includes a substrate 101, a cavity 102, a piezoelectric thin film 103, a first lower electrode 104, a first upper electrode 105, and a second lower electrode. 106, a second upper electrode 107, a first insulator 108, and a second insulator 109.

The first and second lower electrodes 104 and 106 and the first and second upper electrodes 105 and 107 are made of, for example, molybdenum (Mo). The piezoelectric thin film 103 is formed of a piezoelectric material such as aluminum nitride (AlN). The first and second insulators 108 and 109 are made of, for example, silicon dioxide (SiO ₂ ).

First, the details of the structure of the multimode thin film acoustic wave resonator filter 100 according to the first embodiment will be described.
The first lower electrode 104, the first upper electrode 105, and a portion of the piezoelectric thin film 103 sandwiched between both electrodes constitute a first input / output vibration unit 110. The second input / output vibrating portion 111 is configured by the second lower electrode 106, the second upper electrode 107, and a part of the piezoelectric thin film 103 sandwiched between both electrodes. The first and second input / output vibrating sections 110 and 111 form a vibrating section of a multimode thin film acoustic wave resonator filter. “Upper part” and “lower part” are terms for facilitating the explanation and do not limit the absolute positional relationship. The first insulator 108 is formed under the first input / output vibration unit 110. The second insulator 109 is formed on the second input / output vibration unit 111. The first and second input / output vibration units 110 and 111 are placed on the substrate 101. A cavity 102 for confining vibration is formed in the substrate 101.

  With the above structure, the first and second input / output vibration units 110 and 111 exist in the same vibration region, and are not mechanically separated. Ideally, a plurality of nodes whose ends are nodes in the horizontal direction. The higher-order mode is provided. Here, filter characteristics can be obtained by using several vibration modes of a plurality of higher-order modes. The cavity 102 can be said to be a common vibration coupling unit for coupling the vibrations of the first and second input / output vibration units 110 and 111 in common by securing the vibrations.

The structure of the multimode thin film acoustic wave resonator filter 100 has the following four characteristics.
1. The first input / output vibration part 110 and the second input / output vibration part 111 are formed adjacent to each other without a gap.
2. The first lower electrode 104 and the second lower electrode 106 are electrically insulated.
3. The first upper electrode 105 and the second upper electrode 107 are electrically insulated.
4). The resonance frequency in the thickness direction of the first input / output vibration section 110 is substantially equal to the resonance frequency in the thickness direction of the second input / output vibration section 111.

  The condition for realizing the above features 1 to 3 is that the thickness of the first insulator 108 is first made larger than the thickness of the second lower electrode 106. Here, in a general manufacturing process, since the deposition amount of the piezoelectric thin film 103 is managed by time, the thickness of the piezoelectric thin film 103 deposited on the first lower electrode 104 and the second lower electrode 106 are The thickness of the piezoelectric thin film 103 deposited on the substrate becomes equal. Therefore, a step difference between the upper surface of the second lower electrode 106 and the upper surface of the first lower electrode 104 usually appears as a surface step of the piezoelectric thin film 103. Next, the thickness of the second upper electrode 107 is made smaller than the surface step of the piezoelectric thin film 103. And in order to implement | achieve said characteristic 4, the thickness of the 2nd insulator 109 is adjusted. For example, the height position of the upper surface of the second insulator 109 is made substantially equal to the height position of the upper surface of the first input / output vibration unit 110 (first upper electrode 105).

  Next, the operation of the multimode thin film acoustic wave resonator filter 100 according to the first embodiment will be described. FIG. 2 is a diagram showing a vibration mode distribution of the multimode thin film elastic wave resonator filter 100 according to the first embodiment. FIG. 3 is a circuit symbol showing the multimode thin film elastic wave resonator filter 100 according to the first embodiment.

  In the example of FIG. 2, one end surface portion of each of the first and second input / output vibration units 110 and 111 is a fixed end, and a higher-order mode with both fixed ends as nodes is generated. Among the higher-order modes that are generated, the modes that can be efficiently combined and obtain the filter characteristics are the first-order mode and the second-order mode. The integral value of the vibration mode distribution is equal to the amount of charge generated in the piezoelectric thin film 103. Therefore, by adopting a structure in which the first input / output vibration part 110 and the second input / output vibration part 111 are adjacent to each other without a gap, there is no electrodeless part that causes charge loss between both vibration parts, The generated charge can be used efficiently.

  Further, the resonant frequency in the thickness direction of the first input / output vibrating section 110 and the resonant frequency of the second input / output vibrating section 111 are configured to be approximately equal, so that the excited lateral vibration wave is transmitted to one vibrating section. It is possible to propagate without loss to the other oscillating portion without being confined in the. Therefore, the first and second input / output vibration units 110 and 111 can more efficiently excite vibration. Thereby, the degree of coupling can be improved, and low-loss and wideband characteristics can be realized.

  As described above, according to the multimode thin film acoustic wave resonator filter 100 according to the first embodiment of the present invention, the first input / output vibration unit 110 and the second input / output vibration unit 111 are connected to the above-described 1. Forming according to ˜4 structural features, effectively couples the two vibration modes. As a result, the generated charges can be used efficiently, and low-loss and broadband characteristics can be realized.

  As a modification of the first embodiment, for example, a multimode thin film elastic wave resonator filter 200 shown in FIG. 4 can be considered. The multimode thin film acoustic wave resonator filter 200 has a structure including a first insulator 208 and a second insulator 209 that span the first input / output vibration unit 110 and the second input / output vibration unit 111. . The first insulator 208 is formed by integrating an insulator having a certain thickness newly inserted into the lower surfaces of the first and second input / output vibrating portions 110 and 111 and the first insulator 108. is there. The second insulator 209 is an integrated structure of an insulator having a certain thickness, which is newly laminated on the upper surfaces of the first and second input / output vibrating portions 110 and 111, and the second insulator 109. is there. The second insulator 209 only needs to have a mass that substantially equalizes the resonance frequencies of the first and second input / output vibration units 110 and 111. Needless to say, a combination of the first insulator 108 and the second insulator 209 and a combination of the first insulator 208 and the second insulator 109 are also possible.

(Second Embodiment)
In the first embodiment, a multimode thin film acoustic wave resonator filter suitable for a circuit (FIG. 3) that needs to insulate the four electrodes 104 to 107 has been described. However, as a multimode thin film acoustic wave resonator filter, a circuit in which two electrodes are grounded as shown in FIGS. 5 and 8 is often used. In such a circuit, it is not necessary to insulate the two grounded electrodes, that is, it is not necessary to consider the above-described feature 2 and feature 3.
Therefore, in the second embodiment, a multimode thin film acoustic wave resonator filter suitable for the circuit shown in FIG. 5 will be described.

  FIG. 6 is a cross-sectional view of a multimode thin film acoustic wave resonator filter 300 according to the second embodiment of the present invention. In FIG. 6, a multimode thin film acoustic wave resonator filter 300 includes a substrate 101, a cavity 102, a piezoelectric thin film 103, a lower electrode 304, a first upper electrode 105, a second upper electrode 107, And an insulator 109. As can be seen in FIG. 6, the structure of the lower electrode 304 in the second embodiment is different from that in the first embodiment. In addition, about the part which has the function similar to the structure which concerns on 1st Embodiment, the same referential mark is attached | subjected and description is abbreviate | omitted.

  A part of the lower electrode 304, the first upper electrode 105, and a part of the piezoelectric thin film 103 sandwiched between both electrodes constitute a first input / output vibration unit 110. A part of the lower electrode 304, the second upper electrode 107, and a part of the piezoelectric thin film 103 sandwiched between both electrodes constitute a second input / output vibration unit 111. The thickness of the lower electrode 304 is different between a part constituting the first input / output vibration part 110 and a part constituting the second input / output vibration part 111. That is, the multimode thin film elastic wave resonator filter 300 is formed integrally with the first and second lower electrodes 104 and 106 in the multimode thin film elastic wave resonator filter 100 using the first insulator 108 as an electrode material. Structure.

  As described above, according to the multimode thin film acoustic wave resonator filter 300 according to the second embodiment of the present invention, the first input / output vibration unit 110 and the second input / output vibration unit 111 are connected to the above-described 1. Forming according to 3 and 4 structural features, effectively couples the two vibration modes. As a result, the generated charges can be used efficiently, and low-loss and broadband characteristics can be realized.

  Further, as a modification of the second embodiment, for example, a multimode thin film elastic wave resonator filter 400 shown in FIG. 7 is conceivable. The multimode thin film acoustic wave resonator filter 400 has a structure having an insulator 209 that spans between the first input / output vibrating section 110 and the second input / output vibrating section 111. The insulator 209 is formed by integrating the insulator 109 with an insulator having a certain thickness, which is newly laminated on the upper surfaces of the first and second input / output vibrating portions 110 and 111. The insulator 209 only needs to have a mass that substantially equalizes the resonance frequencies of the first and second input / output vibrating portions 110 and 111.

(Third embodiment)
Next, in the third embodiment, a multimode thin film acoustic wave resonator filter suitable for the circuit shown in FIG. 8 will be described.
FIG. 9 is a cross-sectional view of a multimode thin film acoustic wave resonator filter 500 according to the third embodiment of the present invention. In FIG. 9, a multimode thin film acoustic wave resonator filter 500 includes a substrate 101, a cavity 102, a piezoelectric thin film 103, a first lower electrode 104, a second lower electrode 106, an upper electrode 505, And an insulator 108. As can be seen from FIG. 9, the structure of the upper electrode 505 in the third embodiment is different from that in the first embodiment. In addition, about the part which has the function similar to the structure which concerns on 1st Embodiment, the same referential mark is attached | subjected and description is abbreviate | omitted. In FIG.

  A part of the first lower electrode 104, a part of the upper electrode 505, and a part of the piezoelectric thin film 103 sandwiched between both electrodes constitute a first input / output vibration unit 110. A part of the second lower electrode 106, a part of the upper electrode 505, and a part of the piezoelectric thin film 103 sandwiched between both electrodes constitute a second input / output vibration unit 111. The thickness of the upper electrode 505 is different between a part constituting the first input / output vibration part 110 and a part constituting the second input / output vibration part 111. That is, the multimode thin film acoustic wave resonator filter 500 is integrally formed with the first and second upper electrodes 104 and 106 using the second insulator 109 as an electrode material in the multimode thin film acoustic wave resonator filter 100. Structure.

  As described above, according to the multimode thin film acoustic wave resonator filter 500 according to the third embodiment of the present invention, the first input / output vibration unit 110 and the second input / output vibration unit 111 are connected to the above-mentioned 1. Forming according to 2 and 4 structural features, effectively couples the two vibration modes. As a result, the generated charges can be used efficiently, and low-loss and broadband characteristics can be realized.

  As a modification of the third embodiment, for example, a multimode thin film elastic wave resonator filter 600 shown in FIG. 10 is conceivable. The multimode thin film acoustic wave resonator filter 600 has a structure having an insulator 608 that spans between the first input / output vibrating section 110 and the second input / output vibrating section 111. The insulator 608 is formed by integrating an insulator of a certain thickness newly inserted into the lower surfaces of the first and second input / output vibrating portions 110 and 111 and the insulator 108.

(Fourth embodiment)
In the fourth embodiment, another modification of the first embodiment will be described.
FIG. 11 is a cross-sectional view of a multimode thin film acoustic wave resonator filter 700 according to the fourth embodiment of the present invention. In FIG. 11, a multimode thin film acoustic wave resonator filter 700 includes a substrate 101, a cavity 102, a piezoelectric thin film 103, a first lower electrode 104, a second lower electrode 106, and a first upper electrode. 105, a second upper electrode 107, a first insulator 708, and a second insulator 709. As can be seen in FIG. 11, the structure of the first insulator 708 and the second insulator 709 is different in the fourth embodiment from the first embodiment. In addition, about the part which has the function similar to the structure which concerns on 1st Embodiment, the same referential mark is attached | subjected and description is abbreviate | omitted.

  The first insulator 708 is formed from the upper surface position of the first lower electrode 104 to the lower surface position of the second lower electrode 106. The first insulator 708, the first lower electrode 104, and the second lower electrode 106 are designed so as to satisfy the above feature 2. The second insulator 709 is formed from the upper surface position of the first upper electrode 105 to the lower surface position of the second upper electrode 107. The second insulator 709, the first upper electrode 105, and the second upper electrode 107 are designed to satisfy the above feature 3.

  As described above, according to the multimode thin film elastic wave resonator filter 700 according to the fourth embodiment of the present invention, the first input / output vibrating unit 110 and the second input / output vibrating unit 111 are connected to the above-mentioned 1. Forming according to ˜4 structural features, effectively couples the two vibration modes. As a result, the generated charges can be used efficiently, and low-loss and broadband characteristics can be realized.

  As a modification of the fourth embodiment, for example, a multimode thin film elastic wave resonator filter 800 shown in FIG. 12 is conceivable. The multimode thin film acoustic wave resonator filter 800 has a structure including a first insulator 808 and a second insulator 809 that span the first input / output vibrating section 110 and the second input / output vibrating section 111. . The first insulator 808 is formed by integrating an insulator having a certain thickness newly inserted into the lower surfaces of the first and second input / output vibrating portions 110 and 111 and the first insulator 708. is there. The second insulator 809 is formed by integrating an insulator having a certain thickness, which is newly laminated on the upper surfaces of the first and second input / output vibrating portions 110 and 111, and the second insulator 709. is there. The second insulator 809 only needs to have a mass that makes the resonance frequencies of the first and second input / output vibrating portions 110 and 111 substantially equal. Needless to say, a combination of the first insulator 708 and the second insulator 809 and a combination of the first insulator 808 and the second insulator 709 are also possible.

  In the multimode thin film acoustic wave resonator filter described in the first to fourth embodiments, an acoustic mirror layer in which low acoustic impedance layers and high acoustic impedance layers are alternately arranged instead of the cavity 102. Even if is used, the same effect can be obtained. Further, in at least one of the first input / output vibration unit 110 and the second input / output vibration unit 111, the lower electrode 104 or 106 and the upper electrode 105 or 107 are used as balanced input / output terminal electrodes. Type multimode thin film acoustic wave resonator filter can be realized.

(Fifth embodiment)
In the first to fourth embodiments, the example of the multimode thin film acoustic wave resonator filter having two input / output vibration units has been described. However, in the present invention, a multi-mode thin film acoustic wave resonator filter having three or more input / output vibration units can be easily configured.
Hereinafter, in the fifth to eighth embodiments, a case where three input / output vibration units are provided will be described.

  FIG. 13 is a cross-sectional view of a multimode thin film acoustic wave resonator filter 900 according to the fifth embodiment of the present invention. In FIG. 10, a multimode thin film acoustic wave resonator filter 900 includes a substrate 101, a cavity 102, a piezoelectric thin film 103, a first lower electrode 904, a first upper electrode 905, and a second lower electrode. 906, a second upper electrode 907, a third lower electrode 908, a third upper electrode 909, a first insulator 910, a second insulator 911, a third insulator 912, Is provided.

  The first to third lower electrodes 904, 906, and 908 and the first to third upper electrodes 905, 907, and 909 are made of, for example, molybdenum. The piezoelectric thin film 103 is formed of a piezoelectric material such as aluminum nitride. The first to third insulators 910 to 912 are made of, for example, silicon dioxide.

First, details of the structure of the multimode thin film acoustic wave resonator filter 900 according to the fifth embodiment will be described.
The first input / output vibration unit 913 is configured by the first lower electrode 904, the first upper electrode 905, and a part of the piezoelectric thin film 103 sandwiched between both electrodes. The second input / output vibration unit 914 is configured by the second lower electrode 906, the second upper electrode 907, and a part of the piezoelectric thin film 103 sandwiched between both electrodes. A third input / output vibration unit 915 is configured by the third lower electrode 908, the third upper electrode 909, and a part of the piezoelectric thin film 103 sandwiched between both electrodes. The first to third input / output vibration parts 913 to 915 form a vibration part of a multimode thin film acoustic wave resonator filter. The first to third input / output vibration units 913 to 915 are placed on the substrate 101. A cavity 102 for confining vibration is formed in the substrate 101.

  With the above structure, the first to third input / output vibration portions 913 to 915 are present in the same vibration region, are not mechanically separated, and ideally a plurality of nodes whose ends are nodes in the horizontal direction. The higher-order mode is provided. Here, filter characteristics can be obtained by using several vibration modes of a plurality of higher-order modes. It can be said that the cavity 102 is a common vibration coupling part for coupling these vibrations by securing the vibrations of the first to third input / output vibration parts 913 to 915 in common.

The structure of the multimode thin film acoustic wave resonator filter 900 has the following four characteristics.
1. First to third input / output vibration portions 913 to 915 are formed adjacent to each other without gaps.
2. The first to third lower electrodes 904, 906, and 908 are electrically insulated from each other.
3. The first to third upper electrodes 905, 907 and 909 are electrically insulated from each other.
4). The resonance frequency in the thickness direction of the first input / output vibration portion 913, the resonance frequency in the thickness direction of the second input / output vibration portion 914, and the resonance frequency in the thickness direction of the third input / output vibration portion 915 are substantially equal. .

  The condition for realizing the above features 1 to 3 is that the thickness of the first insulator 108 is first made larger than the thicknesses of the second and third lower electrodes 906 and 908. Here, in the general manufacturing process, since the deposition amount of the piezoelectric thin film 103 is managed by time, the thickness of the piezoelectric thin film 103 deposited on the first lower electrode 904, and the second and third lower portions The thickness of the piezoelectric thin film 103 deposited on the electrodes 906 and 908 is equal. Therefore, a step difference between the upper surfaces of the second and third lower electrodes 906 and 908 and the upper surface of the first lower electrode 904 usually appears as a surface step of the piezoelectric thin film 103. Next, the thickness of the second and third upper electrodes 907 and 909 is made smaller than the surface step of the piezoelectric thin film 103. And in order to implement | achieve said characteristic 4, the thickness of the 2nd and 3rd insulators 911 and 912 is adjusted. For example, the height positions of the upper surfaces of the second and third insulators 911 and 912 are made substantially equal to the height position of the upper surface of the first input / output vibration unit 910 (first upper electrode 905).

  Next, the operation of the multimode thin film acoustic wave resonator filter 900 according to the fifth embodiment will be described. FIG. 14 is a diagram showing a vibration mode distribution of the multimode thin film acoustic wave resonator filter 900 according to the fifth embodiment.

  In the example of FIG. 14, one end surface portion of each of the second and third input / output vibration units 914 and 915 serves as a fixed end, and a higher-order mode with both fixed ends as nodes is generated. Among the higher-order modes that are generated, the modes that can be efficiently combined and obtain the filter characteristics are the first-order mode and the third-order mode. The integral value of the vibration mode distribution is equal to the amount of charge generated in the piezoelectric thin film 103. Therefore, by adopting a structure in which the first to third input / output vibrating portions 913 to 915 are adjacent to each other without a gap, there is no electrodeless portion for losing charges between the vibrating portions, and the generated charges are efficiently generated. Can be used.

  Further, the resonance frequency in the thickness direction of the first input / output vibration unit 913, the resonance frequency of the second input / output vibration unit 914, and the resonance frequency in the thickness direction of the third input / output vibration unit 915 are configured to be approximately equal. By doing so, the excited lateral vibration wave can be propagated to other vibration parts without loss without being confined in some vibration parts. Therefore, the first to third input / output vibration units 913 to 915 can more efficiently excite vibration. Thereby, the degree of coupling can be improved, and low-loss and wideband characteristics can be realized.

  As described above, according to the multimode thin film acoustic wave resonator filter 900 according to the fifth embodiment of the present invention, the first to third input / output vibrating portions 913 to 915 are configured as described in the above 1-4. It is formed according to the characteristic features and effectively couples the two vibration modes. As a result, the generated charges can be used efficiently, and low-loss and broadband characteristics can be realized.

  Further, as a modification of the fifth embodiment, for example, a multimode thin film elastic wave resonator filter 1000 shown in FIG. 15 is conceivable. The multimode thin film acoustic wave resonator filter 1000 has a structure including a first insulator 1010 and a second insulator 1011 that span the first to third input / output vibrating portions 913 to 915. The first insulator 1010 is an integrated structure of an insulator having a certain thickness newly inserted into the lower surface of the first to third input / output vibrating portions 913 to 915 and the first insulator 910. is there. The second insulator 1011 includes an insulator having a certain thickness newly laminated on the top surfaces of the first to third input / output vibrating portions 913 to 915 and the second and third insulators 911 and 912. It is a one-piece construction. The second insulator 1011 only needs to have a mass that substantially equalizes the resonance frequencies of the first to third input / output vibrating portions 913 to 915.

(Sixth embodiment)
FIG. 16 is a cross-sectional view of a multimode thin film acoustic wave resonator filter 1100 according to the sixth embodiment of the present invention. In FIG. 16, a multimode thin film acoustic wave resonator filter 1100 includes a substrate 101, a cavity 102, a piezoelectric thin film 103, a first lower electrode 904, a second lower electrode 906, and a third lower electrode. 908, a first upper electrode 905, a second upper electrode 907, a third upper electrode 909, a first insulator 1110, and a second insulator 1111. As can be seen in FIG. 16, the sixth embodiment differs from the fifth embodiment in the structure of the first and second insulators 1110 and 1111. In FIG. 16, parts having the same functions as those in the fifth embodiment are denoted by the same reference numerals, and description thereof is omitted.

  The first input / output vibration unit 913 is configured by the first lower electrode 904, the first upper electrode 905, and a part of the piezoelectric thin film 103 sandwiched between both electrodes. The second input / output vibration unit 914 is configured by the second lower electrode 906, the second upper electrode 907, and a part of the piezoelectric thin film 103 sandwiched between both electrodes. A third input / output vibration unit 915 is configured by the third lower electrode 908, the third upper electrode 909, and a part of the piezoelectric thin film 103 sandwiched between both electrodes. The first insulator 1110 is formed in a step shape only on the lower surfaces of the first lower electrode 904 and the second lower electrode 906. The thickness of each step is designed to satisfy the above feature 2. Further, the second insulator 1111 is formed in a step shape only on the top surfaces of the first upper electrode 905 and the third lower electrode 909. The thickness of each step is designed to satisfy the above feature 3.

  As described above, according to the multimode thin film acoustic wave resonator filter 1100 according to the sixth embodiment of the present invention, the first to third input / output vibrating portions 913 to 915 are configured as described in the above 1-4. It is formed according to the characteristic features and effectively couples the two vibration modes. As a result, the generated charges can be used efficiently, and low-loss and broadband characteristics can be realized.

  As a modification of the sixth embodiment, for example, a multimode thin film elastic wave resonator filter 1200 shown in FIG. 17 can be considered. The multimode thin film acoustic wave resonator filter 1200 has a structure including a first insulator 1210 and a second insulator 1211 that span the first to third input / output vibration portions 913 to 915. The first insulator 1210 is formed by integrating an insulator of a certain thickness newly inserted into the lower surface of the first to third input / output vibrating portions 913 to 915 and the first insulator 1110. is there. The second insulator 1211 is formed by integrating an insulator having a certain thickness, which is newly laminated on the top surfaces of the first to third input / output vibrating portions 913 to 915, and the second insulator 1111. is there. The second insulator 1211 only needs to have a mass that substantially equalizes the resonance frequencies of the first to third input / output vibrating portions 913 to 915.

(Seventh embodiment)
FIG. 18 is a cross-sectional view of a multimode thin film acoustic wave resonator filter 1300 according to the seventh embodiment of the present invention. In FIG. 18, a multimode thin film acoustic wave resonator filter 1300 includes a substrate 101, a cavity 102, a piezoelectric thin film 103, a first lower electrode 904, a second lower electrode 906, and a third lower electrode. 908, a first upper electrode 905, a second upper electrode 907, a third upper electrode 909, a first insulator 1310, and a second insulator 1311. As can be seen in FIG. 18, the seventh embodiment differs from the fifth embodiment in the structure of the first and second insulators 1310 and 1311. In FIG. 18, portions having the same functions as those in the fifth embodiment are denoted by the same reference numerals, and description thereof is omitted.

  The first input / output vibration unit 913 is configured by the first lower electrode 904, the first upper electrode 905, and a part of the piezoelectric thin film 103 sandwiched between both electrodes. The second input / output vibration unit 914 is configured by the second lower electrode 906, the second upper electrode 907, and a part of the piezoelectric thin film 103 sandwiched between both electrodes. A third input / output vibration unit 915 is configured by the third lower electrode 908, the third upper electrode 909, and a part of the piezoelectric thin film 103 sandwiched between both electrodes. The first insulator 1310 is formed only on the lower surface of the first lower electrode 904. The thickness to be formed is designed to satisfy the above feature 2. In addition, the second insulator 1311 is formed only on the upper surface of the first upper electrode 905. The thickness to be formed is designed to satisfy the above feature 3.

  As described above, according to the multimode thin film acoustic wave resonator filter 1300 according to the seventh embodiment of the present invention, the first to third input / output vibrating portions 913 to 915 are configured as described in the above 1-4. It is formed according to the characteristic features and effectively couples the two vibration modes. As a result, the generated charges can be used efficiently, and low-loss and broadband characteristics can be realized.

  As a modification of the seventh embodiment, for example, a multimode thin film elastic wave resonator filter 1400 shown in FIG. 19 is conceivable. The multimode thin film acoustic wave resonator filter 1400 has a structure including a first insulator 1410 and a second insulator 1411 that span the first to third input / output vibrating portions 913 to 915. The first insulator 1410 is formed by integrating an insulator of a certain thickness newly inserted into the lower surface of the first to third input / output vibrating portions 913 to 915 and the first insulator 1310. is there. The second insulator 1411 is an integrated structure of an insulator having a certain thickness, which is newly stacked on the top surfaces of the first to third input / output vibrating portions 913 to 915, and the second insulator 1311. is there. The second insulator 1411 only needs to have a mass that substantially equalizes the resonance frequencies of the first to third input / output vibrating portions 913 to 915.

(Eighth embodiment)
FIG. 20 is a cross-sectional view of a multimode thin film acoustic wave resonator filter 1500 according to the eighth embodiment of the present invention. In FIG. 20, a multimode thin film acoustic wave resonator filter 1500 includes a substrate 101, a cavity 102, a piezoelectric thin film 103, a first lower electrode 904, a second lower electrode 906, and a third lower electrode. 908, first upper electrode 905, second upper electrode 907, third upper electrode 909, first insulator 1510, second insulator 1511, third insulator 1512, And a fourth insulator 1513. As can be seen in FIG. 20, the eighth embodiment differs from the fifth embodiment in the structure of the first to fourth insulators 1510 to 1513. In FIG. 20, parts having the same functions as those in the fifth embodiment are denoted by the same reference numerals, and description thereof is omitted.

  The first input / output vibration unit 913 is configured by the first lower electrode 904, the first upper electrode 905, and a part of the piezoelectric thin film 103 sandwiched between both electrodes. The second input / output vibration unit 914 is configured by the second lower electrode 906, the second upper electrode 907, and a part of the piezoelectric thin film 103 sandwiched between both electrodes. A third input / output vibration unit 915 is configured by the third lower electrode 908, the third upper electrode 909, and a part of the piezoelectric thin film 103 sandwiched between both electrodes. The first insulator 1510 is formed only on the lower surface of the second lower electrode 906. The third insulator 1512 is formed only on the lower surface of the third lower electrode 908. These formation thicknesses are designed to satisfy the above feature 2. In addition, the second insulator 1511 is formed only on the upper surface of the second upper electrode 907. The fourth insulator 1513 is formed only on the upper surface of the third upper electrode 909. These formed thicknesses are designed so as to satisfy the above feature 3.

  As described above, according to the multimode thin film acoustic wave resonator filter 1500 according to the eighth embodiment of the present invention, the first to third input / output vibrating portions 913 to 915 are configured as described in the above 1-4. It is formed according to the characteristic features and effectively couples the two vibration modes. As a result, the generated charges can be used efficiently, and low-loss and broadband characteristics can be realized.

  Further, as a modification of the eighth embodiment, for example, a multimode thin film acoustic wave resonator filter 1600 shown in FIG. 21 is conceivable. The multimode thin film acoustic wave resonator filter 1600 has a structure including a first insulator 1610 and a second insulator 1611 that span the first to third input / output vibrating portions 913 to 915. The first insulator 1610 includes an insulator having a certain thickness newly inserted into the lower surface of the first to third input / output vibrating portions 913 to 915 and the first and third insulators 1510 and 1512. It is a one-piece construction. The second insulator 1611 includes an insulator having a certain thickness, which is newly stacked on the top surfaces of the first to third input / output vibrating portions 913 to 915, and the second and fourth insulators 1511 and 1513. It is a one-piece construction. The second insulator 1611 only needs to have a mass that substantially equalizes the resonance frequencies of the first to third input / output vibrating portions 913 to 915.

In the multimode thin film acoustic wave resonator filter described in the fifth to eighth embodiments, an acoustic mirror layer in which low acoustic impedance layers and high acoustic impedance layers are alternately arranged is used instead of the cavity 102. Even if it uses, the same effect is acquired. FIG. 22 shows an example of a structure using an acoustic mirror layer in the multimode thin film acoustic wave resonator filter 100 according to the first embodiment.
In addition, the second lower electrode 906 and the third upper electrode 909 or the second upper electrode 907 and the third lower electrode of the multimode thin film acoustic wave resonator filter described in the fifth to eighth embodiments. By using the electrode 908 as a balanced input / output terminal electrode, a balanced multimode thin film acoustic wave resonator filter can be realized.

The multimode thin film acoustic wave resonator filters described in the fifth to eighth embodiments may have a concentric structure on the upper surface. Specifically, if a columnar piezoelectric resonator is formed on the inner side and a donut columnar piezoelectric resonator is formed on the outer side, a concentric multimode thin film acoustic wave resonator filter is formed.
Furthermore, the structures described in the second to fourth embodiments can be employed for the multimode thin film acoustic wave resonator filters described in the fifth to eighth embodiments.

(Ninth embodiment)
In the ninth embodiment, an application example of the multimode thin film acoustic wave resonator filter of the present invention will be described.
FIG. 23 is a circuit diagram of a ladder type filter 1700 using the multimode thin film acoustic wave resonator filter of the present invention. In FIG. 23, a ladder type filter 1700 includes a plurality of thin film elastic wave resonators 1701 connected in series, a plurality of thin film elastic wave resonators 1702 connected in parallel to the plurality of thin film elastic wave resonators 1701, and an output. And a multimode thin film acoustic wave resonator filter 1703 of the present invention connected to a location. The thin film elastic wave resonators 1701 and 1702 are not limited to the number shown in FIG. 23 as long as they are connected in a ladder shape. Further, the location where the multimode thin film acoustic wave resonator filter 1703 is connected is not limited to the example of FIG.

  Thus, by connecting the multimode thin film acoustic wave resonator of the present invention to a ladder type filter composed of a thin film acoustic wave resonator, a filter having a low loss and a wide band characteristic can be configured.

  FIG. 24 is a block diagram showing a configuration of a communication device 1800 using the multimode thin film acoustic wave resonator filter of the present invention. 24, a communication device 1800 includes a transmission circuit 1805, a reception circuit 1806, multimode thin film acoustic wave resonator filters 1801 and 1802, a switch circuit 1803, and an antenna 1804. The multimode thin film acoustic wave resonator filter 1801 is connected between the transmission circuit 1805 and the switch circuit 1803 and has a characteristic of passing through the transmission frequency band. The multimode thin film acoustic wave resonator filter 1802 is connected between the reception circuit 1806 and the switch circuit 1803 and has a characteristic of passing through the reception frequency band. The switch circuit 1803 switches whether the signal from the transmission circuit 1805 is propagated to the antenna 1804 side or the signal from the antenna 1804 is propagated to the reception circuit 1806 side.

  Thus, by using the multimode thin film acoustic wave resonator filter of the present invention for a communication device, it is possible to configure a communication device having a low loss and a wide band characteristic.

  FIG. 25 is a block diagram showing a configuration of a duplexer 1900 using the multimode thin film acoustic wave resonator filter of the present invention. The duplexer 1900 includes a multimode thin film elastic wave resonator filter 1901 of the present invention connected to the transmission circuit side, a multimode thin film elastic wave resonator filter 1902 of the present invention connected to the reception circuit side, and an isolation shift. And a phaser 1903. The multimode thin film elastic wave resonator filters 1901 and 1902 of the present invention are, for example, the multimode thin film elastic wave resonator filters 300 and 400 shown in FIGS.

  With the configuration shown in FIG. 25, the multimode thin film elastic wave resonator filter 1901 allows only signals in the transmission frequency band to pass. The multimode thin film acoustic wave resonator filter 1902 passes only signals in the reception frequency band. As a result, the transmission signal is radiated from the antenna 1904 without wrapping around the reception circuit, and the reception signal from the antenna 1904 is propagated to the reception circuit without wrapping around the transmission circuit. Therefore, a low-loss and wide-band duplexer can be configured.

  In addition, the multimode thin film acoustic wave resonator filter of the present invention can be used as long as the device requires filter characteristics.

  The thin film acoustic wave resonator filter using a plurality of modes according to the present invention, a duplexer including the same, and a communication device can realize a low loss and a wide band, and are useful for wireless devices and the like.

Sectional drawing of the multimode thin film elastic wave resonator filter 100 which concerns on the 1st Embodiment of this invention The figure which shows the vibration mode distribution of the multimode thin film elastic wave resonator filter 100 Circuit symbol for multimode thin film acoustic wave resonator filter Sectional drawing of the multimode thin film elastic wave resonator filter 200 which is a modification of 1st Embodiment Other circuit symbols representing multimode thin film acoustic wave resonator filters Sectional drawing of the multimode thin film elastic wave resonator filter 300 which concerns on the 2nd Embodiment of this invention. Sectional drawing of the multimode thin film elastic wave resonator filter 400 which is a modification of 2nd Embodiment Other circuit symbols representing multimode thin film acoustic wave resonator filters Sectional drawing of the multimode thin film elastic wave resonator filter 500 which concerns on the 3rd Embodiment of this invention. Sectional drawing of the multimode thin film elastic wave resonator filter 600 which is a modification of 3rd Embodiment. Sectional drawing of the multimode thin film elastic wave resonator filter 700 which concerns on the 4th Embodiment of this invention. Sectional drawing of the multimode thin film elastic wave resonator filter 800 which is a modification of 4th Embodiment Sectional drawing of the multimode thin film elastic wave resonator filter 900 which concerns on the 5th Embodiment of this invention. The figure which shows the vibration mode distribution of the multimode thin film elastic wave resonator filter 900 Sectional drawing of the multimode thin film elastic wave resonator filter 1000 which is a modification of 5th Embodiment Sectional drawing of the multimode thin film elastic wave resonator filter 1100 which concerns on the 6th Embodiment of this invention. Sectional drawing of the multimode thin film elastic wave resonator filter 1200 which is a modification of 6th Embodiment Sectional drawing of the multimode thin film elastic wave resonator filter 1300 which concerns on the 7th Embodiment of this invention. Sectional drawing of the multimode thin film elastic wave resonator 1400 of the modification of 7th Embodiment Sectional drawing of the multimode thin film elastic wave resonator filter 1500 which concerns on the 8th Embodiment of this invention. Sectional drawing of the multimode thin film elastic wave resonator 1600 of the modification of 8th Embodiment. Sectional view of a multimode thin film acoustic wave resonator filter of the present invention using a mirror acoustic layer Circuit diagram of ladder-type filter 1700 using the multimode thin film acoustic wave resonator filter of the present invention The block diagram which shows the structure of the communication apparatus 1800 using the multimode thin film elastic wave resonator filter of this invention. The block diagram which shows the structure of the duplexer 1900 using the multimode thin film elastic wave resonator filter of this invention. The figure which shows the structure of the conventional MCF The figure which shows another structure of the conventional MCF A sectional view of a conventional multimode thin film acoustic wave resonator filter 70 and an ideal vibration mode distribution. Sectional view of other conventional multimode thin film acoustic wave resonator filter and diagram showing ideal vibration mode distribution

Explanation of symbols

100-1500, 1703, 1801, 1802, 1901, 1902 Multimode thin film acoustic wave resonator filter 101 Substrate 102 Cavity 103 Piezoelectric thin films 104-107, 304, 505, 904-909 Electrodes 108-109, 208-209, 608 , 708 to 709, 808 to 809, 910 to 912, 1010 to 1011, 1210 to 1211, 1310 to 1311, 1410 to 1411, 1510 to 1513, 1610 to 1611 Insulators 110 to 111, 913 to 915 Ladder type filters 1701, 1702 Thin film elastic wave resonator 1800 Communication equipment 1803 Switch circuit 1804, 1904 Antenna 1805 Transmitter circuit 1806 Receiver circuit 1900 Duplexer 1903 Isolation phase shifter

Claims (20)

A multimode thin film acoustic wave resonator filter comprising:
A first input / output vibration unit that is disposed adjacent to each other and sandwiches a part of the piezoelectric body between the first lower electrode and the first upper electrode, and a part of the piezoelectric body is a second lower electrode. A vibration part including at least a second input / output vibration part sandwiched between the first upper electrode and the second upper electrode;
A common vibration securing unit that mounts the vibration unit and couples the plurality of vibrations by securing at least the vibration of the first input / output vibration unit and the vibration of the second input / output vibration unit in common. When,
At least for forming a step for electrically insulating at least one of the first lower electrode and the second lower electrode and at least one of the first upper electrode and the second upper electrode. A multimode thin film acoustic wave resonator filter comprising one insulator. A first insulator thicker than the second lower electrode of the second input / output vibration part is formed under the first lower electrode of the first input / output vibration part,
A second insulator thicker than the first upper electrode of the first input / output vibration unit is formed on the second upper electrode of the second input / output vibration unit. The multimode thin film acoustic wave resonator filter according to claim 1.   3. The multimode thin film elastic wave resonator filter according to claim 2, wherein the second insulator has a thickness that makes the resonance frequencies of the first and second input / output vibrating portions substantially equal to each other. .   The multimode thin film acoustic wave resonator filter according to claim 2, wherein the second insulator is formed up to an upper surface of the first upper electrode.   5. The multimode thin film acoustic wave resonator filter according to claim 4, wherein the second insulator has a mass that substantially equalizes the resonance frequencies of the first and second input / output vibrating portions. The first insulator is formed in a shape to be inserted between the second lower electrode and the piezoelectric body,
3. The multimode thin film elastic wave resonator filter according to claim 2, wherein the second insulator is formed in a shape to be inserted between the first upper electrode and the piezoelectric body. .   The multimode thin film elastic wave resonance according to claim 6, wherein the first and second insulators have masses that substantially equalize the resonance frequencies of the first and second input / output vibration units. Filter.   The multimode thin film acoustic wave resonator filter according to claim 6, wherein the second insulator is formed up to an upper surface of the first upper electrode.   9. The multimode thin film acoustic wave resonator filter according to claim 8, wherein the second insulator has a mass that substantially equalizes the resonance frequencies of the first and second input / output vibrating portions. The vibration unit is a third input / output vibration unit that is disposed adjacent to the first input / output vibration unit and includes a portion of the piezoelectric body sandwiched between a third lower electrode and a third upper electrode. Further comprising
The common vibration securing unit combines the plurality of vibrations by securing the vibrations of the first to third input / output vibration units in common,
A third insulator thicker than the first upper electrode of the first input / output vibration part is formed on the third upper electrode of the third input / output vibration part,
3. The multimode thin film acoustic wave resonator according to claim 2, wherein the first insulator is formed thicker than a third lower electrode of the third input / output vibration unit.   11. The multimode thin film elastic wave resonator filter according to claim 10, wherein the third insulator has a thickness that substantially equalizes the resonance frequencies of the first and third input / output vibrating portions. .   11. The multimode thin film acoustic wave resonator filter according to claim 10, wherein the second and third insulators are an integral layer formed up to the top surface of the first upper electrode.   The multimode thin film acoustic wave resonator filter according to claim 12, wherein the second and third insulators have masses that substantially equalize resonance frequencies of the first to third input / output vibration units. The first lower electrode of the first input / output vibration part and the second lower electrode of the second input / output vibration part are electrically connected,
The insulator, which is thicker than the first upper electrode of the first input / output vibration part, is formed on the second upper electrode of the second input / output vibration part. 2. The multimode thin film acoustic wave resonator filter according to 1.   15. The multimode thin film acoustic wave resonator filter according to claim 14, wherein the insulator has a thickness that makes resonance frequencies of the first and second input / output vibration parts substantially equal.   The multimode thin film acoustic wave resonator filter according to claim 1, wherein the resonance vibration securing unit is a cavity formed in a substrate.   The multimode thin film acoustic wave resonator filter according to claim 1, wherein the resonance vibration securing unit is an acoustic mirror layer having high acoustic impedance layers and low acoustic impedance layers alternately. A ladder-type filter including a multimode thin film acoustic wave resonator filter,
The multi-mode thin film acoustic wave resonator filter includes:
A first input / output vibration unit that is disposed adjacent to each other and sandwiches a part of the piezoelectric body between the first lower electrode and the first upper electrode, and a part of the piezoelectric body is a second lower electrode. A vibration part including at least a second input / output vibration part sandwiched between the first upper electrode and the second upper electrode;
A common vibration securing unit that mounts the vibration unit and couples the plurality of vibrations by securing at least the vibration of the first input / output vibration unit and the vibration of the second input / output vibration unit in common. When,
At least for forming a step for electrically insulating at least one of the first lower electrode and the second lower electrode and at least one of the first upper electrode and the second upper electrode. A ladder-type filter comprising one insulator. A duplexer comprising a multimode thin film acoustic wave resonator filter,
The multi-mode thin film acoustic wave resonator filter includes:
A first input / output vibration unit that is disposed adjacent to each other and sandwiches a part of the piezoelectric body between the first lower electrode and the first upper electrode, and a part of the piezoelectric body is a second lower electrode. A vibration part including at least a second input / output vibration part sandwiched between the first upper electrode and the second upper electrode;
A common vibration securing unit that mounts the vibration unit and couples the plurality of vibrations by securing at least the vibration of the first input / output vibration unit and the vibration of the second input / output vibration unit in common. When,
At least for forming a step for electrically insulating at least one of the first lower electrode and the second lower electrode and at least one of the first upper electrode and the second upper electrode. A duplexer comprising one insulator. There is a communication device including a multimode thin film acoustic wave resonator filter,
The multi-mode thin film acoustic wave resonator filter includes:
A first input / output vibration unit that is disposed adjacent to each other and sandwiches a part of the piezoelectric body between the first lower electrode and the first upper electrode, and a part of the piezoelectric body is a second lower electrode. A vibration part including at least a second input / output vibration part sandwiched between the first upper electrode and the second upper electrode;
A common vibration securing unit that mounts the vibration unit and couples the plurality of vibrations by securing at least the vibration of the first input / output vibration unit and the vibration of the second input / output vibration unit in common. When,
At least for forming a step for electrically insulating at least one of the first lower electrode and the second lower electrode and at least one of the first upper electrode and the second upper electrode. A communication device comprising one insulator.

Images