JP6368332B2 - Filters and duplexers - Google Patents

Description

  The present invention relates to a filter and a duplexer, for example, a ladder-type filter and a duplexer.

  An elastic wave filter using an elastic wave device is used, for example, in a duplexer for mobile multi-communication. For example, a surface acoustic wave filter is used as the acoustic wave filter. In the surface acoustic wave filter, an IDT (Interdigital Transducer) that excites surface acoustic waves is formed on a piezoelectric substrate. It is known that a chip on which an acoustic wave filter is formed is flip-chip mounted on a substrate using bumps (Patent Documents 1 to 4). It is known to use bumps for heat dissipation of the chip.

JP 2007-184690 A JP 2006-042007 A JP 2000-196407 A JP 2007-116628 A

  A piezoelectric substrate has a large linear thermal expansion coefficient. For this reason, when temperature changes, frequencies, such as a pass band of a filter, will change.

  The present invention has been made in view of the above problems, and an object thereof is to suppress the temperature dependence of the frequency.

The present invention includes a piezoelectric substrate, a plurality of series resonators having an IDT provided on the piezoelectric substrate, and connected in series between an input terminal and an output terminal, and the piezoelectric substrate. One or a plurality of parallel resonators having an IDT and connected in parallel to a line between the input terminal and the output terminal; and provided on the piezoelectric substrate, and being the most of the plurality of series resonators One or a plurality of bumps including a first bump provided in the elastic wave propagation direction of the first resonator which is a series resonator having a high anti-resonance frequency, and a linear thermal expansion coefficient of the piezoelectric substrate in the elastic wave propagation direction A mounting substrate having a smaller linear thermal expansion coefficient and flip-chip mounting the piezoelectric substrate using the one or a plurality of bumps , wherein the first resonator is a part of the plurality of series resonators The antiresonance frequency is different from the series resonator of Serial to the propagation direction of the elastic wave of at least one of the series resonators of the part of the series resonators wherein the one or more bumps is a filter not provided.

The present invention includes a piezoelectric substrate, a plurality of series resonators having an IDT provided on the piezoelectric substrate, and connected in series between an input terminal and an output terminal, and the piezoelectric substrate. A plurality of parallel resonators having an IDT and connected in parallel to a line between the input terminal and the output terminal, and provided on the piezoelectric substrate, are most anti-resonant among the plurality of series resonators 1 including a first bump provided in the propagation direction of each elastic wave of the first resonator, which is a series resonator having a high frequency and a parallel resonator having the lowest resonance frequency among the plurality of parallel resonators. Or a plurality of bumps, a mounting substrate having a linear thermal expansion coefficient smaller than the linear thermal expansion coefficient in the propagation direction of the elastic wave of the piezoelectric substrate, and mounting the piezoelectric substrate flip chip using the one or more bumps, A plurality of the series resonators Out at least one different resonant frequency and the second series resonator, at least one of the plurality of parallel resonators have different resonant frequencies and other parallel resonators, the first resonator, the plurality of series The one or the plurality of bumps are provided in the resonator and the plurality of parallel resonators, respectively, and in the propagation direction of the elastic wave of the series resonators other than the first resonator among the plurality of series resonators. not be provided, is a filter that is not provided any said in the first propagation direction of the acoustic wave parallel resonator other than the resonator wherein the one or more bumps of the plurality of parallel resonators .

The said structure WHEREIN : The said 1st bump can be set as the structure provided in the both sides of the propagation direction of the said elastic wave of the said 1st resonator.

The said structure WHEREIN: The said 1st bump can be set as the structure provided in the propagation direction of the elastic wave of opening of the said 1st resonator.

In the above configuration, the distance between the first bump and the first resonator is a second distance provided in the propagation direction of the elastic wave of the second resonator other than the first resonator among the one or the plurality of bumps . The distance between the bump and the second resonator can be smaller.

  In the above configuration, the first resonator has a configuration in which the propagation direction of the elastic wave is different from that of the one or more series resonators and the one or more parallel resonators other than the second resonator other than the first resonator. It can be.

In the above configuration, the first bump may be connected to a dummy or a ground.

  The present invention is a duplexer including the filter.

  In the above configuration, the first filter connected between the common terminal and the first terminal, the pass band higher than the pass band of the first filter, and connected between the common terminal and the second terminal. When the first filter is the filter, the first resonator is a series resonator, and when the second filter is the filter, the first resonator is in parallel resonance. It can be set as the device.

  According to the present invention, the temperature dependence of frequency can be suppressed.

FIG. 1A and FIG. 1B are cross-sectional views of samples used for simulation. FIGS. 2A to 2D are plan views of simulated samples A1 to A4 and B1 to B4. FIGS. 3A to 3C are plan views of simulated samples A5 to A7 and B5 to B7. FIG. 4 is a diagram showing linear thermal expansion coefficients in samples A1 to A7. FIG. 5 is a diagram showing linear thermal expansion coefficients in samples B1 to B7. FIG. 6 is a plan view of a chip used in the first embodiment. 7A and 7B are cross-sectional views taken along the line AA in FIG. FIG. 8A is a plan view of the resonator used in the first embodiment, and FIG. 8B is a cross-sectional view taken along line AA of FIG. FIG. 9 is a diagram illustrating attenuation characteristics of the resonators according to the first embodiment. FIG. 10 is a plan view of a chip used in the first modification of the first embodiment. FIG. 11 is a plan view of a chip used in the second modification of the first embodiment. FIG. 12 is a plan view of a chip used in the third modification of the first embodiment. FIG. 13 is a plan view of a chip used in the fourth modification of the first embodiment. FIG. 14 is a circuit diagram of a duplexer according to the second embodiment.

  The temperature coefficient of frequency (TCF) is determined by the sum of the coefficient of linear thermal expansion (TEC) and the temperature coefficient of phase velocity (TCV: Temperature Coefficient of Velocity). Therefore, attention was paid to the linear thermal expansion coefficient. Using protruding electrodes such as bumps, the temperature coefficient of the frequency was approached to 0 (that is, the absolute value was reduced).

  FIG. 1A and FIG. 1B are cross-sectional views of samples used for simulation. As shown in FIG. 1A, in the sample A, the chip 11 mainly includes a piezoelectric substrate 10. The chip 11 is flip-chip mounted on the mounting substrate 20 using bumps 22. The bump 22 and the mounting substrate 20 are bonded to each other. The thickness of the piezoelectric substrate 10 is the thickness T11. As shown in FIG. 1B, in the sample B, the chip 11 mainly includes a piezoelectric substrate 10 and a support substrate 28. The piezoelectric substrate 10 is attached to the upper surface (the lower surface in FIG. 1B) of the support substrate 28. The thicknesses of the piezoelectric substrate 10 and the support substrate 28 are T12 and T13, respectively. Other configurations are the same as those of the sample A, and a description thereof will be omitted.

  For samples A and B, the linear thermal expansion coefficients of the following samples A1 to A7 and samples B1 to B7 were simulated. FIGS. 2A to 3C are plan views of simulated samples A1 to A7 and B1 to B7. As shown in FIG. 2A, the chip 11 has a short side with a length L1 and a long side with a length L2. The short side direction of the chip 11 is the X direction, the long side direction is the Y direction, and the normal direction of the top surface of the chip 11 is the Z direction. The X direction, the Y direction, and the Z direction do not necessarily match the X axis direction, the Y axis direction, and the Z axis direction of the crystal orientation of the piezoelectric substrate 10. The region 23 is a region where the bumps 22 are formed with other samples, but the bumps 22 are not formed with this sample. The points for simulating the linear thermal expansion coefficient are a point 50a at the center of the chip 11, a point 50b at a distance L3 in the −X direction from the center, and a point 50c at a distance L3 in the + X direction from the center. Points 50 a to 50 c are assumed to be IDTs formed on the piezoelectric substrate 10. In samples A1 and B1, bumps are not formed on the upper surface of the chip 11.

  As shown in FIG. 2B, bumps 22 are formed in samples A2 and B2. The bump 22 is not provided around the points 50a to 50c. Other configurations are the same as those in FIG. As shown in FIG. 2C, in the samples A3 and B3, the bump 22a is provided at the position of the distance L4 in the −X direction of the point 50b. Bumps are not provided in the + X direction of the point 50c. Other configurations are the same as those in FIG. As shown in FIG. 2D, in the samples A4 and B4, the bump 22b is provided at the position of the distance L4 in the + X direction of the point 50c. Bumps are not provided in the −X direction of the point 50b. Other configurations are the same as those in FIG.

  As shown in FIG. 3A, in the samples A5 and B5, the bump 22a is provided at the position of the distance L4 in the −X direction and the distance L5 in the −Y direction of the point 50b. A bump 22b is provided at a position of a distance L4 in the + X direction and a distance L5 in the -Y direction of the point 50c. Other configurations are the same as those in FIG. As shown in FIG. 3B, in the samples A6 and B6, the bump 22a is provided at the position of the distance L4 in the −X direction and the distance L6 in the −Y direction of the point 50b. A bump 22b is provided at a position of a distance L4 in the + X direction and a distance L6 in the -Y direction of the point 50c. Other configurations are the same as those in FIG. As shown in FIG. 3C, in the samples A7 and B7, the bump 22a is provided at the position of the distance L4 in the −X direction of the point 50b. A bump 22b is provided at a distance L4 in the + X direction of the point 50c. Other configurations are the same as those in FIG.

The simulation conditions are shown below.
Piezoelectric substrate 10: 42 ° rotation Y-cut X-propagation lithium tantalate substrate Young's modulus: 254 Gpa
Poisson's ratio: 0.21
Linear thermal expansion coefficient: 16.1 ppm / ° C. (X direction), 9.5 ppm (Y direction) / ° C., 10.7 ppm / ° C. (Z direction)
Support substrate 28: Sapphire substrate Young's modulus: 470 GPa
Poisson's ratio: 0.245
Linear thermal expansion coefficient: 7.35 ppm / ° C
Thickness T11 of piezoelectric substrate 10 of sample A: 0.28 mm
Thickness T12 of sample B piezoelectric substrate 10: 0.03 mm
Thickness T13 of support substrate 28 of sample B: 0.25 mm
Chip 11 short side length L1: 0.88 mm
Long side length L2 of chip 11: 1.03 mm
Linear thermal expansion coefficient of the mounting substrate 20: 0 ppm / ° C.
Bump 22: Au layer (film thickness: 12.5 μm)
Bump 22 diameter: 75 μm
Distance L3: 0.165mm
Distance L4: 0.1475mm
Distance L5: 0.10mm
Distance L6: 0.05mm

The temperature was changed from −40 ° C. to 125 ° C., and the linear thermal expansion coefficient was simulated from the change in the distance from the points 50a to 50c. FIG. 4 is a diagram showing linear thermal expansion coefficients in samples A1 to A7. The linear thermal expansion coefficient of each sample is shown below.
Sample A1: 16.10 ppm / ° C
Sample A2: 15.35 ppm / ° C
Sample A3: 14.47 ppm / ° C
Sample A4: 13.98 ppm / ° C
Sample A5: 13.12 ppm / ° C
Sample A6: 12.83 ppm / ° C
Sample A7: 12.61 ppm / ° C

  As shown in FIG. 4, the linear thermal expansion coefficient of the sample A <b> 1 where the bumps 22 are not provided is the linear thermal expansion coefficient in the X direction of the piezoelectric substrate 10. When the bump 22 is formed as in the sample A2, the linear thermal expansion coefficient is slightly smaller than that in the sample A1. When any of the bumps 22a and 22b is provided in the X direction of the points 50b and 50c like the samples A3 and A4, the linear thermal expansion coefficient is smaller than that of the sample A2. The reason why the samples A3 and A4 have different linear thermal expansion coefficients is considered because the arrangement of the bumps 22 other than the bumps 22a and 22b is not symmetrical in the X direction. When both the bumps 22a and 22b are provided as in the samples A5 to A7, the linear thermal expansion coefficient is smaller than those of the samples A3 and A4. Like the samples A5 and A6, the bumps 22a and 22b may be provided so as to be shifted in the Y direction from the X direction of the points 50b and 50c. The linear thermal expansion coefficient becomes smaller as the deviation in the Y direction (distances L5 and L6) of the bumps 22a and 22b is smaller.

FIG. 5 is a diagram showing linear thermal expansion coefficients in samples B1 to B7. The linear thermal expansion coefficient of each sample is shown below.
Sample B1: 9.55 ppm / ° C
Sample B2: 9.31 ppm / ° C
Sample B3: 8.95 ppm / ° C
Sample B4: 8.65 ppm / ° C
Sample B5: 8.30 ppm / ° C
Sample B6: 8.17 ppm / ° C
Sample B7: 8.08 ppm / ° C

  As shown in FIG. 5, samples B1 to B7 have a smaller linear thermal expansion coefficient than samples A1 to A7. This is because the linear thermal expansion coefficient of the support substrate 28 is smaller than that of the piezoelectric substrate 10. That is, the support substrate 28 suppresses expansion and contraction of the surface of the piezoelectric substrate 10 due to heat. The tendency of the linear thermal expansion coefficient of samples B1 to B7 is the same as that of samples A1 to A7.

  Based on the above simulation results, an acoustic wave device having a filter with a small temperature dependence of the passband will be described as an example.

  FIG. 6 is a plan view of a chip used in the first embodiment. 7A and 7B are cross-sectional views taken along the line AA in FIG. FIG. 7A is an example in which the support substrate is not provided, and FIG. 7B is an example in which the piezoelectric substrate 10 is attached on the support substrate 28. As shown in FIGS. 6 and 7A, in the chip 11, one or more series resonators S1 to S4, one or more parallel resonators P1 to P3, wirings 34 and one or more on the piezoelectric substrate 10 are provided. Bumps 22 are provided. Each resonator includes an IDT 30 and reflectors 32 provided on both sides of the IDT 30. The bump 22 includes an input bump T1, an output bump T2, a ground bump Tg, and bumps 22a and 22b. The chip 11 is flip-chip mounted (or face-down mounted) on the mounting substrate 20 using bumps 22. Thereby, the input bump T1, the output bump T2, and the ground bump Tg are electrically connected to an electrode pad or the like formed on the mounting substrate 20. The wiring 34 electrically connects each resonator and between each resonator and the bump 22. The wiring 34 is a metal film such as a Cu (copper) film, an Al (aluminum) film, or an Au (gold) film, and may include the metal film 18 (see FIG. 8B). The bumps 22 that are protruding electrodes may be stud Au bumps, Cu pillars formed by plating, or solder balls such as AuSn, SnAgCu, or SnAg.

  The series resonators S1 to S4 are connected in series via the wiring 34 between the input bump T1 (ie, input terminal) and the output bump T2 (ie, output terminal). The parallel resonators P1 to P3 are connected in parallel via the wiring 34 to the line between the input bump T1 and the output bump T2. Thus, the series resonators S1 to S4 and the parallel resonators P1 to P3 function as a ladder type filter. Bumps 22a and 22b are formed on both sides of the series resonator S3 and the parallel resonator P2 in the X direction (acoustic wave propagation direction).

  FIG. 8A is a plan view of the resonator used in the first embodiment, and FIG. 8B is a cross-sectional view taken along line AA of FIG. As shown in FIGS. 8A and 8B, in the 1-port resonator, the IDT 30 and the reflector 32 are formed on the piezoelectric substrate 10. The piezoelectric substrate 10 is, for example, a lithium niobate substrate or a lithium tantalate substrate. The IDT 30 and the reflector 32 are formed by the metal film 18 formed on the piezoelectric substrate 10. The metal film 18 is, for example, a Cu (copper) film or an Al (aluminum) film. The IDT 30 includes a pair of opposing comb electrodes 16. The comb electrode 16 includes a plurality of electrode fingers 12 and a bus bar 14 to which the plurality of electrode fingers 12 are connected. The pair of comb-shaped electrodes 16 are provided facing each other such that the electrode fingers 12 are substantially staggered. The IDT 30 mainly excites an elastic wave propagating in the arrangement direction (X direction) of the electrode fingers 12. The elastic wave is reflected by the reflector 32. The pitch of the electrode fingers 12 in the comb electrode 16 substantially corresponds to the wavelength λ of the elastic wave excited by the comb electrode 16.

  FIG. 9 is a diagram illustrating attenuation characteristics of the resonators according to the first embodiment. As shown in FIG. 9, the attenuation pole on the high frequency side of the pass band of the ladder filter is formed by the antiresonance points of the series resonators S1 to S4. The attenuation pole on the low frequency side of the pass band is formed by the resonance points of the parallel resonators P1 to P3. The series resonator S3 having the highest anti-resonance frequency among the series resonators has the greatest influence on the skirt characteristic on the high frequency side of the pass band. The parallel resonator P2 having the lowest resonance frequency among the parallel resonators has the most influence on the skirt characteristic on the low frequency side of the pass band. In order to suppress the temperature dependence of the passband, it is effective to reduce the temperature dependence of the series resonator S3 and the parallel resonator P2.

  Therefore, as shown in FIG. 6, bumps 22a and 22b are provided on both sides in the X direction of each of the series resonator S3 and the parallel resonator P2. Thereby, like the samples A7 and B7, the linear thermal expansion coefficients in the series resonator S3 and the parallel resonator P2 are reduced. The TCF of the series resonator S3 and the parallel resonator P2 is suppressed. Therefore, the temperature dependence of the skirt characteristic of the passage characteristic is reduced, and the temperature dependence of the passage area is reduced.

  The interval between the antiresonance frequency and the resonance frequency does not change depending on the resonator. Therefore, the series resonator S3 can be said to be the series resonator having the highest resonance frequency among the series resonators S1 to S4. The parallel resonator P2 can be said to be the parallel resonator having the lowest antiresonance frequency among the parallel resonators P1 to P3.

  In the experiment using samples A1 to A7 and B1 to B7, the linear thermal expansion coefficient of the mounting substrate 20 was assumed to be zero. In the first embodiment, the mounting substrate 20 having a linear thermal expansion coefficient smaller than the linear thermal expansion coefficient in the X direction of the piezoelectric substrate 10 is used. For example, the linear thermal expansion coefficient in the X direction of the lithium tantalate substrate is 16.1 ppm / ° C. Therefore, ceramics are used as the mounting substrate 20. For example, the linear thermal expansion coefficient of fine ceramics using alumina is 7.2 ppm / ° C. Thereby, the linear thermal expansion coefficient in a resonator can be made small. As the mounting substrate 20, an organic material such as a resin may be used.

  In the example of FIG. 7B, the piezoelectric substrate 10 is bonded to the support substrate 28. Other configurations are the same as those in FIG. When the piezoelectric substrate 10 is pasted on the support substrate 28, it is effective if the linear thermal expansion coefficient of the mounting substrate 20 is smaller than the linear thermal expansion coefficient of the piezoelectric substrate 10, but smaller than the linear thermal expansion coefficient of the support substrate 28. Is preferred.

  According to the first embodiment, the bump 22a is formed on the piezoelectric substrate 10 in the elastic wave propagation direction of the series resonator S3 (first resonator) having the highest antiresonance frequency among the plurality of series resonators S1 to S4. And 22b are provided. Bumps 22a and 22b are provided in the elastic wave propagation direction of the parallel resonator P2 (first resonator) having the lowest resonance frequency among the plurality of parallel resonators P1 to P3. Thereby, the temperature characteristic of a pass band can be suppressed. The bumps 22a and 22b may be provided on at least one of the series resonator S3 and the parallel resonator P2.

  The antiresonance frequencies of the series resonators S1 to S4 may all be the same. In this case, the bumps 22a and 22b may be provided in at least one X direction of the series resonators S1 to S4. Further, the resonance frequencies of the parallel resonators P1 to P3 may all be the same. In this case, the bumps 22a and 22b may be provided in at least one X direction of the parallel resonators P1 to P3.

  At least one of the series resonators S1 to S4 may have a different antiresonance frequency from the other series resonators. In this case, the bumps 22a and 22b may be provided in the X direction of the series resonator S3 having the highest antiresonance frequency. At least one of the parallel resonators P1 to P3 may have a resonance frequency different from that of the other parallel resonators. In this case, the bumps 22a and 22b may be provided in the X direction of the parallel resonator P2 having the lowest resonance frequency.

  The bumps 22a and 22b may not be provided in the X direction of some of the series resonators S1, S2, or S4 among the series resonators S1 to S4. The bumps 22a and 22b may not be provided in the X direction of some of the parallel resonators P1 and P2 among the parallel resonators P1 to P3. As a result, the number of bumps 22 can be reduced. Therefore, the area of the chip 11 can be reduced.

  When the bumps 22a and 22b are provided on both the series resonator S3 having a high anti-resonance frequency and the parallel resonator P2 having the lowest resonance frequency, the elasticity of the series resonators S1, S2, and S4 other than the series resonator S3 is provided. It is preferable not to provide the bumps 22a and 22b in the wave propagation direction and to provide the bumps 22a and 22b in the elastic wave propagation direction of the parallel resonators P1 and P3 other than the parallel resonator P2. Thereby, the temperature dependence of the passing area is reduced, and the area of the chip 11 can be reduced.

  As in the samples A3, A4, B3, and B4, only one of the bumps 22a and 22b may be provided. As in the samples A7 and B7, the bumps 22a and 22b are preferably provided on both sides of the series resonator S3 and the parallel resonator P2 in the X direction in order to reduce the linear thermal expansion coefficient.

  The bumps 22a and 22b may be ground bumps like the bump 22b corresponding to the parallel resonator P2. The bumps 22a and 22b may be dummy bumps like the other bumps 22a and 22b. The ground bump is a bump electrically connected to the ground. A ground wiring is provided between the ground bump and the ground. Heat is easily conducted through the wiring. Therefore, heat dissipation can be improved by using at least one of the bumps 22a and 22b as a ground bump. The dummy bump is not connected to the ground wiring or the signal wiring and is electrically floating. Therefore, by making at least one of the bumps 22a and 22b a dummy, interference between the bump and the resonator can be suppressed.

(Modification 1 of Example 1)
FIG. 10 is a plan view of a chip used in the first modification of the first embodiment. As shown in FIG. 10, in addition to the series resonator S3 and the parallel resonator P2, bumps 22b are also provided in the X direction of the parallel resonator P3. The series resonator S3 and the parallel resonator P3 share the bump 22b. Other configurations are the same as those in the first embodiment, and a description thereof is omitted.

  As in the first modification of the first embodiment, the bumps 22a and 22b may be provided in a plurality of parallel resonators P2 and P3 among the parallel resonators P1 to P3. Also in the series resonator, bumps 22a and 22b may be provided on a plurality of series resonators. Further, the bump 22a or 22b may be shared by a plurality of resonators.

(Modification 2 of Example 1)
FIG. 11 is a plan view of a chip used in the second modification of the first embodiment. As shown in FIG. 11, bumps 22 a and 22 b are provided by shifting in the −Y direction with respect to the middle line 54 extending in the X direction of the series resonator S <b> 3 and the parallel resonator P <b> 2. Other configurations are the same as those of the first embodiment, and the description thereof is omitted.

  Like the samples A5, A6, B5, and B6, the bumps 22a and 22b may be shifted in the Y direction from the center line of the resonator. It is preferable that at least a part of the bumps 22a and 22b overlap with the resonator when viewed from the X direction in plan view. Further, it is more preferable that at least a part of the bumps 22a and 22b overlap with the opening of the resonator (a region where electrode fingers overlap in the IDT) when viewed from the X direction. Furthermore, it is more preferable that at least a part of the bumps 22a and 22b overlap with a center line extending in the X direction of the resonator.

(Modification 3 of Example 1)
FIG. 12 is a plan view of a chip used in the third modification of the first embodiment. As shown in FIG. 12, the planar view shapes of the bumps 22a and 22b located in the X direction of the series resonator S3 are elliptical. The bumps 22a and 22b located in the X direction of the parallel resonator P2 have a rectangular shape in plan view. Other configurations are the same as those of the first embodiment, and the description thereof is omitted.

  As in the third modification of the first embodiment, the shape of the bump can be arbitrarily set. When the bumps 22a and 22b are stud bumps, the shape in plan view is circular. When solder balls are used, the bumps 22a and 22b are spherical. When the plated bump is used, the shape in plan view can be made arbitrary.

(Modification 4 of Example 1)
FIG. 13 is a plan view of a chip used in the fourth modification of the first embodiment. As shown in FIG. 13, the propagation direction of the elastic wave of the parallel resonator P3 is the Y direction. Bumps 22a and 22b are provided in the Y direction of the parallel resonator P3. Other configurations are the same as those of the first embodiment, and the description thereof is omitted.

  As in the fourth modification of the first embodiment, at least one of the resonators may have a different propagation direction of the elastic wave. When a Y-cut X-propagating lithium tantalate substrate is used, the linear thermal expansion coefficient in the X direction (X-axis direction) of the upper surface of the piezoelectric substrate 10 is the largest. For example, when the parallel resonator P3 has the lowest resonance frequency among the parallel resonators P1 to P3, if the propagation direction of the elastic wave of the parallel resonator P3 is the Y direction, the linear thermal expansion coefficient becomes small. Further, bumps 22a and 22b are provided in the Y direction of the resonator. Thereby, a linear thermal expansion coefficient becomes smaller. As described above, the propagation direction of the elastic wave of the resonator (for example, the parallel resonator P3) that reduces the temperature dependence of the frequency is set to the series resonators S1 to S4 and the parallel resonators P1 and P3 other than the parallel resonator P3. And the bumps 22a and 22b may be provided.

  The bumps 22a and 22b are preferably closest to the resonator that suppresses temperature dependency. That is, the distance between the series resonator S3 and the bumps 22a and 22b closest to the series resonator S3 having the highest antiresonance frequency is set to the series resonator S1, S2 or S4 (second resonator) other than the series resonator S3. The distance between the nearest bump 22 (second bump) and the series resonator S1, S2 or S4 is smaller. The distance between the parallel resonator P2 and the bumps 22a and 22b closest to the parallel resonator P2 having the lowest resonance frequency is the bump closest to the parallel resonator P1 or P3 (second resonator) other than the parallel resonator P2. It is smaller than the distance between 22 (second bump) and the parallel resonator P1 or P3. This can reduce the linear thermal expansion coefficient of the resonator that most affects the temperature dependence of the passband.

  The number of series resonators and parallel resonators in the first embodiment and its modifications can be set as appropriate. Although an example in which one filter is formed on the chip 11 has been described, a plurality of filters may be formed on the chip 11. Although the example which uses a surface acoustic wave as an elastic wave was demonstrated, you may use a boundary acoustic wave or a Love wave.

  Example 2 is an example of a duplexer. FIG. 14 is a circuit diagram of a duplexer according to the second embodiment. As shown in FIG. 14, a transmission filter 44 (first filter) is connected between the common terminal Ant and the transmission terminal Tx (first terminal). A reception filter 46 (second filter) is connected between the common terminal Ant and the reception terminal Rx (second terminal). The transmission filter 44 passes a signal in the transmission band among signals input from the transmission terminal Tx as a transmission signal to the common terminal Ant, and suppresses signals of other frequencies. The reception filter 46 passes the signal in the reception band among the signals input from the common terminal Ant to the reception terminal Rx as a reception signal, and suppresses signals of other frequencies. At least one of the transmission filter 44 and the reception filter 46 can be the filter of the first embodiment and its modification.

  For example, the pass band of the reception filter 46 is higher than the pass band of the transmission filter 44. A band between the pass band of the reception filter 46 and the pass band of the transmission filter 44 is a guard band. It is preferable that the temperature change of the skirt characteristic on the guard band side in the pass band is small. Therefore, in the transmission filter 44, it is preferable to provide the bumps 22a and 22b in the propagation direction of the elastic wave of the series resonator having the highest antiresonance frequency. In the reception filter 46, it is preferable to provide the bumps 22a and 22b in the propagation direction of the elastic wave of the parallel resonator having the lowest resonance frequency.

  Although the example of the transmission filter 44 as the first filter and the reception filter 46 as the second filter has been described, the first filter may be the reception filter 46 and the second filter may be the transmission filter 44.

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

DESCRIPTION OF SYMBOLS 10 Piezoelectric substrate 16 Comb-shaped electrode 18 Metal film 20 Mounting substrate 22 Bump 28 Support substrate 30 IDT
32 Reflector

Claims (12)

A piezoelectric substrate;
A plurality of series resonators having an IDT provided on the piezoelectric substrate and connected in series between an input terminal and an output terminal;
One or more parallel resonators having an IDT provided on the piezoelectric substrate and connected in parallel to a line between the input terminal and the output terminal;
One or more including a first bump provided on the piezoelectric substrate and provided in the propagation direction of the elastic wave of the first resonator which is the series resonator having the highest antiresonance frequency among the plurality of series resonators. With bumps ,
A mounting substrate having a linear thermal expansion coefficient smaller than the linear thermal expansion coefficient in the propagation direction of elastic waves of the piezoelectric substrate, and flip-chip mounting the piezoelectric substrate using the one or more bumps ;
Equipped with,
The first resonator has a different anti-resonance frequency from some of the plurality of series resonators, and the acoustic wave propagation direction of at least one series resonator of the some series resonators is different from that of the series resonators. A filter in which the one or more bumps are not provided .   2. The filter according to claim 1, wherein none of the one or more series resonators is provided with the one or more bumps in a propagation direction of the elastic wave.   A piezoelectric substrate;
  One or more series resonators having an IDT provided on the piezoelectric substrate and connected in series between an input terminal and an output terminal;
  A plurality of parallel resonators having an IDT provided on the piezoelectric substrate and connected in parallel to a line between the input terminal and the output terminal;
  One or a plurality of bumps including a first bump provided in the elastic wave propagation direction of the first resonator which is the parallel resonator having the lowest resonance frequency among the plurality of parallel resonators;
  A mounting substrate having a linear thermal expansion coefficient smaller than the linear thermal expansion coefficient in the propagation direction of elastic waves of the piezoelectric substrate, and flip-chip mounting the piezoelectric substrate using the one or a plurality of bumps,
  The first resonator has a resonance frequency different from that of some of the plurality of parallel resonators, and the elastic wave is propagated in at least one parallel resonator of the some parallel resonators in the propagation direction of the elastic wave. A filter without one or more bumps.   The filter according to claim 3, wherein none of the one or more parallel resonators is provided with the one or more bumps in the propagation direction of the elastic wave. A piezoelectric substrate;
A plurality of series resonators having an IDT provided on the piezoelectric substrate and connected in series between an input terminal and an output terminal;
A plurality of parallel resonators having an IDT provided on the piezoelectric substrate and connected in parallel to a line between the input terminal and the output terminal;
A first resonance provided on the piezoelectric substrate and having a highest anti-resonance frequency among the plurality of series resonators and a parallel resonator having the lowest resonance frequency among the plurality of parallel resonators. One or more bumps including a first bump provided in the propagation direction of each elastic wave of the vessel;
A mounting substrate having a linear thermal expansion coefficient smaller than the linear thermal expansion coefficient in the propagation direction of elastic waves of the piezoelectric substrate, and flip-chip mounting the piezoelectric substrate using the one or more bumps;
Comprising
At least one of the plurality of series resonators has a resonance frequency different from other series resonators,
At least one of the plurality of parallel resonators has a resonance frequency different from other parallel resonators,
The first resonator is provided in each of the plurality of series resonators and the plurality of parallel resonators,
None of the one or the plurality of bumps is provided in the propagation direction of the elastic wave of the series resonator other than the first resonator among the plurality of series resonators,
The filter in which none of the one or the plurality of bumps is provided in the propagation direction of the elastic wave of the parallel resonator other than the first resonator among the plurality of parallel resonators. Wherein the first bump is the first resonator the acoustic wave filter of claim 1 which are provided on both sides of the propagation direction 5 any one claim of. The filter according to any one of claims 1 to 6 , wherein the first bump is provided in a propagation direction of an elastic wave at an opening of the first resonator. The distance between the first bump and the first resonator is the second bump provided in the elastic wave propagation direction of the second resonator other than the first resonator among the one or the plurality of bumps and the first bump . The filter according to any one of claims 1 to 7 , wherein the filter is smaller than a distance from two resonators. Wherein the first resonator, the one or more series resonators and the one or more parallel resonators the first second propagation direction of the resonator and the acoustic wave other than resonators of different claims 5, wherein among the filter. The filter according to any one of claims 1 to 9 , wherein the first bump is connected to a dummy or a ground. Duplexer including a filter according to any one of claims 1 10. Including a filter according to claim 5;
A first filter connected between the common terminal and the first terminal;
A second filter having a higher pass band than the pass band of the first filter and connected between the common terminal and the second terminal;
Comprising
When the first filter is the filter, the first resonator is a series resonator;
The duplexer , wherein when the second filter is the filter, the first resonator is a parallel resonator.

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