JP2012205215A - Surface acoustic wave device and method for manufacturing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a surface acoustic wave device having a package structure adaptable to both of an unbalanced input-unbalanced output type filter and an unbalanced input-balanced output type filter, and having reduced insertion loss.SOLUTION: A surface acoustic wave device has a structure adaptable to both of an unbalanced input-unbalanced output type reception filter and an unbalanced input-balanced output type reception filter. A surface acoustic wave filter chip 30A constituting the unbalanced input-unbalanced output type reception filter has a pad 37f functioning as an unbalanced output terminal, and a pad 37e not connected to a surface acoustic wave filter part. A wiring board has, on a back surface thereof, a single electrode connected to the pad 37f and functioning as a reception terminal, and an electrode connected to the second pad 37e and functioning as a ground terminal.

Description

  The present invention relates to a surface acoustic wave device and a method for manufacturing the same.

  A surface acoustic wave filter using a surface acoustic wave is conventionally known as a filter for extracting a predetermined frequency component. Also, a surface acoustic wave that uses surface acoustic waves in a duplexer or other duplexer that simultaneously filters transmission signals and reception signals having different frequency bands in each frequency band and prevents the inflow of signals from the transmission circuit to the reception circuit. A wave demultiplexer is also conventionally known.

  Conventionally, for example, in Japanese Unexamined Patent Application Publication No. 2003-347964 (Patent Document 1), a surface acoustic wave filter or a surface acoustic wave duplexer is used as an interstage filter or duplexer of a high-frequency circuit in a communication device such as a cellular phone. Various proposals have been made.

  In the RF circuit, a radio frequency integrated circuit (RFIC) is connected to a surface acoustic wave filter and a surface acoustic wave duplexer. The RFIC includes a balanced input type in which a signal is input by a potential difference between two signal lines and an unbalanced input type in which a signal is input by a potential difference between one signal line and a ground line.

  When the RFIC is an unbalanced input type, the surface acoustic wave filter or the reception filter of the surface acoustic wave duplexer is required to be an unbalanced input-unbalanced output type filter. On the other hand, when the RFIC is a balanced input type, the reception filter of the surface acoustic wave filter or the surface acoustic wave duplexer is an unbalanced input-balanced output type filter, that is, a filter having a balanced-unbalanced conversion function. Is required.

  Patent Document 1 describes a surface acoustic wave demultiplexer having a structure that can be used regardless of whether the RFIC is a balanced input type or an unbalanced input type. FIG. 10A in Patent Document 1 (hereinafter simply referred to as “Document 1 FIG. 10A”) shows a reception filter chip when the reception filter is an unbalanced input-unbalanced output type filter. 1B in FIG. 1 (hereinafter simply referred to as “Reference 1 FIG. 10B”) shows a reception filter chip when the reception filter is an unbalanced input-balanced output type filter. FIG. 9A (hereinafter simply referred to as “Document 1 FIG. 9A”) shows the back surface of the surface acoustic wave duplexer package.

  Reference 1 In the example of FIG. 10A, the reception filter chip has a piezoelectric substrate. Then, three interdigital transducer electrodes (hereinafter referred to as “IDT electrodes”) disposed along the propagation direction of the surface acoustic wave on the piezoelectric substrate, and one set disposed on both sides of the three IDT electrodes. Reflectors, a plurality of pads, and a plurality of wirings are formed. The wiring connects the IDT electrode or reflector and the pad. The plurality of pads include one input pad IN, two output pads OUT, and three ground pads GND. The reception filter is composed of an unbalanced input-unbalanced output type longitudinally coupled resonator type surface acoustic wave filter. Therefore, signals of the same phase are output from the two output pads OUT.

  In the example shown in FIG. 10B, the reception filter chip has a piezoelectric substrate. And on the piezoelectric substrate, three IDT electrodes arranged along the propagation direction of the surface acoustic wave, a pair of reflectors arranged on both sides of the three IDT electrodes, a plurality of pads, and a plurality of pads Wiring is formed. The wiring connects the IDT electrode or reflector and the pad. The plurality of pads include one input pad IN, two output pads OUT1 and OUT2, and three ground pads GND. Among the three IDT electrodes, in the IDT electrode located at the center, one of a pair of comb-like electrodes constituting the IDT electrode is constituted by two divided comb-like electrodes. One divided comb-like electrode is connected to the output pad OUT1, and the other divided comb-like electrode is connected to the output pad OUT2. The reception filter is composed of an unbalanced input-balanced output type, that is, a longitudinally coupled resonator type surface acoustic wave filter having a balanced-unbalanced conversion function. Therefore, signals having a phase difference of 180 degrees are output from the two output pads OUT1 and OUT2.

  Reference 1 As shown in FIG. 9A, on the back surface of the surface acoustic wave duplexer package, there are an antenna terminal Antenna, a transmission terminal Tx I / P, three ground terminals Gnd, and two reception terminals Rx O. / P1, Rx O / P2 are formed.

  Reference 1 As shown in FIG. 10A and Reference 1 FIG. 10B, the two receiving filter chips have the same pad arrangement. Therefore, when the RFIC is an unbalanced input type, the reception filter chip shown in FIG. 10A of Reference 1 is mounted on the package. When the RFIC is a balanced input type, the reception filter chip shown in FIG. 10B of Document 1 is mounted on the package. As described above, in the surface acoustic wave duplexer described in Patent Document 1, the reception filter is an unbalanced input-unbalanced output type filter in one package, and the reception filter is an unbalanced input- Both of the balanced output type filters can be dealt with.

JP 2003-347964 A

  In the surface acoustic wave duplexer described in Patent Document 1, two reception terminals (Rx O / P1, Rx O / P2) are provided in order to be compatible with an unbalanced input-balanced output type reception filter. It is necessary to keep. Therefore, when an unbalanced input-unbalanced output type reception filter is mounted, the same signal is output from the two reception terminals (Rx O / P1, Rx O / P2) on the back surface of the package. . Such a configuration causes the following problems.

  First, since the same signal is output from the two receiving terminals (Rx O / P1, Rx O / P2) on the back side of the package, the path through which the received signal flows becomes longer as a whole. As a result, the influence of wiring resistance and parasitic capacitance increases, and the insertion loss of the reception filter increases.

  Further, since the same signal is output from the two receiving terminals (Rx O / P1, Rx O / P2) on the back side of the package, two RF terminals are mounted on the substrate of the RF circuit on which the surface acoustic wave duplexer is mounted. It is necessary to combine two signals output from each of the receiving terminals (Rx O / P1, Rx O / P2) into one. For this reason, it is necessary to separately form wiring for synthesizing signals on the substrate of the high-frequency circuit. For this reason, it is necessary to prepare a high-frequency circuit board corresponding to the surface acoustic wave duplexer.

  The present invention has been made in view of the above problems, and the object of the present invention is applicable to both unbalanced input-unbalanced output type filters and unbalanced input-balanced output type filters. It is an object of the present invention to provide a surface acoustic wave device having a simple package structure and low insertion loss.

  A method of manufacturing a surface acoustic wave device according to the present invention includes a first piezoelectric substrate, a first unbalanced input terminal and first and second balanced output terminals formed on the first piezoelectric substrate, A first surface acoustic wave of the unbalanced input-balanced output type having a first surface acoustic wave filter unit connected between the first unbalanced input terminal and the first and second balanced output terminals. Filter chip or second piezoelectric substrate, second unbalanced input terminal, unbalanced output terminal and ground terminal formed on the second piezoelectric substrate, second unbalanced input terminal and unbalanced input terminal A second surface acoustic wave filter connected to the balanced output terminal, and the arrangement of the unbalanced output terminal and the ground terminal with respect to the second unbalanced input terminal is the first unbalanced input terminal. Same as the arrangement of the first and second balanced output terminals for A step of preparing a second surface acoustic wave filter chip of an unbalanced input-unbalanced output type, a substrate body having a front surface and a back surface facing each other, and first to third lands provided on the surface A step of preparing a wiring board having electrodes and first to third back terminals provided on the back surface and connected to the first to third land electrodes, respectively, and a first surface acoustic wave A step of flip-chip mounting the filter chip or the second surface acoustic wave filter chip on the surface of the wiring board, and when mounting the first surface acoustic wave filter chip on the wiring board, the first unbalanced input terminal Are connected to the first land electrode, the first balanced output terminal is connected to the second land electrode, the second balanced output terminal is connected to the third land electrode, and the second surface acoustic wave filter chip is connected to the wiring board. Actually If you are the second unbalanced input terminal to the first land electrode, an unbalanced output terminal to the second land electrode is connected to the ground terminal to the third land electrode.

  In one embodiment, in the method for manufacturing the surface acoustic wave device, the surface acoustic wave filter section is constituted by a longitudinally coupled resonator type surface acoustic wave filter.

  In one embodiment, in the method for manufacturing the surface acoustic wave device, the second and third back terminals are adjacent to each other on the back surface.

  In one embodiment, in the method for manufacturing a surface acoustic wave device, the surface acoustic wave device is a duplexer including a transmission filter and a reception filter, and the first or second surface acoustic wave filter chip is a reception filter. is there.

  A surface acoustic wave device according to the present invention includes a rectangular piezoelectric substrate, an unbalanced input terminal, an unbalanced output terminal, and a ground terminal formed on the piezoelectric substrate, an unbalanced input terminal, and an unbalanced output terminal. An unbalanced input-unbalanced output type surface acoustic wave filter chip having a surface acoustic wave filter portion connected between the substrate body, a substrate body having a front surface and a back surface facing each other, and a surface provided on the surface A wiring board having first to third land electrodes and first to third back terminals provided on the back surface and connected to the first to third land electrodes, respectively. The balanced output terminal and the ground terminal are arranged symmetrically on the piezoelectric substrate, the second unbalanced input terminal is the first land electrode, the unbalanced output terminal is the second land electrode, and the ground terminal is 3rd run They are respectively connected to the electrodes.

  In one embodiment, in the surface acoustic wave device, the surface acoustic wave surface acoustic wave filter section is constituted by a longitudinally coupled resonator type surface acoustic wave surface acoustic wave filter.

  In one embodiment, in the surface acoustic wave device, the second and third back surface terminals are adjacent to each other on the back surface.

  In one embodiment, in the surface acoustic wave device, the duplexer includes a transmission filter and a reception filter, and the acoustic wave filter chip is a reception filter of the duplexer.

  According to the present invention, it has a structure that can cope with any of the unbalanced input-unbalanced output type reception filter and the unbalanced input-balanced output type reception filter, and has an insertion loss. A small surface acoustic wave device can be provided.

1 is a schematic circuit diagram of a duplexer 1 of the present embodiment (when an RFIC connected to the duplexer 1 is an unbalanced input type). 1 is a schematic circuit diagram of a duplexer 1 according to the present embodiment (when an RFIC connected to the duplexer 1 is a balanced input type). FIG. It is a typical sectional view of the duplexer of this embodiment (and comparative example). FIG. 2 is a schematic plan view of the transmission-side surface acoustic wave filter chip and the reception-side surface acoustic wave filter chip of the duplexer 1 of the present embodiment (when the RFIC connected to the duplexer 1 is an unbalanced input type). FIG. 2 is a schematic plan view of the transmission-side surface acoustic wave filter chip and the reception-side surface acoustic wave filter chip of the duplexer 1 of the present embodiment (when the RFIC connected to the duplexer 1 is a balanced input type). 4 is a schematic perspective plan view of a fourth electrode layer 47 and a third dielectric layer 43 of the wiring board 40 in the duplexer 1 according to the present embodiment. FIG. 4 is a schematic perspective plan view of a third electrode layer 46 and a second dielectric layer 42 of the wiring board 40 in the duplexer 1 according to the present embodiment. FIG. 4 is a schematic perspective plan view of a second electrode layer 45 and a first dielectric layer 41 of the wiring board 40 in the duplexer 1 according to the present embodiment. FIG. 4 is a schematic perspective plan view of a first electrode layer 44 of a wiring board 40 in the duplexer 1 according to the present embodiment. FIG. It is a schematic plan view of a transmission-side surface acoustic wave filter chip 20A and a reception-side surface acoustic wave filter chip 30C of a duplexer of a comparative example. 5 is a schematic perspective plan view of a fourth electrode layer 47 and a third dielectric layer 43 of the wiring board 40 in a duplexer according to a comparative example. FIG. 4 is a schematic perspective plan view of a third electrode layer 46 and a second dielectric layer 42 of a wiring board 40 in a duplexer according to a comparative example. FIG. 4 is a schematic perspective plan view of a second electrode layer 45 and a first dielectric layer 41 of a wiring board 40 in a duplexer according to a comparative example. FIG. 5 is a schematic perspective plan view of a first electrode layer 44 of a wiring board 40 in a duplexer according to a comparative example. FIG. It is a figure which shows the measurement board | substrate for measuring the electrical property of the receiving filter in each of the duplexer 1 which concerns on this Embodiment, and the duplexer of a comparative example. It is a figure which shows the pass characteristic of the receiving filter in each of the duplexer 1 which concerns on this Embodiment, and the duplexer of a comparative example. V. of the reception filter in each of the duplexer 1 according to the present embodiment and the duplexer of the comparative example. S. W. It is a figure which shows R (Voltage Standing Wave Ratio: voltage standing wave ratio).

  Hereinafter, preferred embodiments of the present invention will be described by taking the duplexer 1 shown in FIGS. 1 to 9 as a surface acoustic wave duplexer as an example. However, the duplexer 1 is merely an example. The surface acoustic wave device according to the present invention is not limited to the duplexer 1. The present invention is also applicable to a duplexer other than a duplexer, such as a triplexer.

  In the embodiments described below, the same or corresponding parts are denoted by the same reference symbols, and the description thereof may not be repeated. Further, when referring to the number, amount, and the like, the scope of the present invention is not necessarily limited to the number, amount, and the like unless otherwise specified. In the following embodiments, each component is not necessarily essential for the present invention unless otherwise specified.

  The duplexer 1 according to the present embodiment is mounted on a high-frequency device such as a mobile phone that supports a CDMA (Code Division Multiple Access) system such as UMTS (Universal Mobile Telecommunications System). The duplexer 1 is a duplexer corresponding to UMTS-BAND5. The transmission frequency band of UMTS-BAND5 is 824 MHz to 849 MHz, and the reception frequency band is 869 MHz to 894 MHz.

  The duplexer 1 according to the present embodiment is a surface acoustic wave demultiplexer that can handle the same package regardless of whether the RFIC connected to the duplexer is a balanced input type or an unbalanced input type. It is a vessel.

  FIG. 1 is a schematic circuit diagram of the duplexer 1 of the present embodiment when the RFIC connected to the duplexer is an unbalanced input type. FIG. 2 is a schematic circuit diagram of the duplexer 1 of the present embodiment when the RFIC connected to the duplexer is a balanced input type.

  As shown in FIGS. 1 and 2, the duplexer 1 includes an antenna terminal 11 connected to an antenna and a transmission terminal 12. As shown in FIG. 1, when the RFIC connected to the duplexer is an unbalanced input type, the duplexer 1 has a reception terminal 13. As shown in FIG. 2, when the RFIC connected to the duplexer is a balanced input type, the duplexer 1 has receiving terminals 13a and 13b.

  As shown in FIGS. 1 and 2, a transmission filter 20 is connected between the antenna terminal 11 and the transmission terminal 12. As shown in FIG. 1, when the RFIC connected to the duplexer is an unbalanced input type, a reception filter 30 a is connected between the antenna terminal 11 and the reception terminal 13. As shown in FIG. 2, when the RFIC connected to the duplexer is a balanced input type, a reception filter 30 b is connected between the antenna terminal 11 and the reception terminal 13. As shown in FIGS. 1 and 2, a matching circuit including an inductor L1 is connected between the antenna terminal 11, the transmission filter 20, and the reception filters 30a and 30b. One end of the inductor L1 is connected to the antenna terminal 11, and the other end is connected to the ground.

  As shown in FIGS. 1 and 2, the transmission filter 20 is configured by a ladder-type surface acoustic wave filter. The transmission filter 20 has an output terminal 21 and an input terminal 22. The output terminal 21 is connected to the antenna terminal 11, and the input terminal 22 is connected to the transmission terminal 12.

  The transmission filter 20 includes a series arm 23 that connects between the output terminal 21 and the input terminal 22. In the series arm 23, the series arm resonators S1 to S4 are connected in series. The transmission filter 20 has parallel arms 24-26 connected between the series arm 23 and the ground. The parallel arms 24-26 are provided with parallel arm resonators P1-P3. The series arm resonators S1 to S4 and the parallel arm resonators P1 to P3 are each constituted by a surface acoustic wave resonator.

  An inductor L2 is connected between the parallel arm resonator P1 and the ground. An inductor L3 is connected between the parallel arm resonators P2 and P3 and the ground.

  As shown in FIG. 1, the reception filter 30a is configured by a longitudinally coupled resonator type surface acoustic wave filter. The reception filter 30a is an unbalanced input-unbalanced output type filter. Therefore, the reception filter 30a has an unbalanced input terminal 31 and an unbalanced output terminal 32. The unbalanced input terminal 31 is connected to the antenna terminal 11, and the unbalanced output terminal 32 is connected to the receiving terminal 13. The reception filter 30a includes a surface acoustic wave resonator 33 and first and second longitudinally coupled resonator surface acoustic wave filter units 34 connected between the unbalanced input terminal 31 and the unbalanced output terminal 32. , 35.

  Further, as shown in FIG. 2, the reception filter 30b is configured by a longitudinally coupled resonator type surface acoustic wave filter, similarly to the reception filter 30a shown in FIG. The reception filter 30b is an unbalanced input-balanced output type filter. That is, the reception filter 30b is constituted by a balanced longitudinally coupled resonator type surface acoustic wave filter having a balanced-unbalanced conversion function. Therefore, the reception filter 30b has an unbalanced input terminal 31 and first and second balanced output terminals 32a and 32b. The unbalanced input terminal 31 is connected to the antenna terminal 11, and the first and second balanced output terminals 32a and 32b are connected to the first and second receiving terminals 13a and 13b. The reception filter 30b includes a surface acoustic wave resonator 33 and first and second longitudinally coupled resonators connected between the unbalanced input terminal 31 and the first and second balanced output terminals 32a and 32b. Type surface acoustic wave filter sections 34a and 35a.

  FIG. 3 is a schematic cross-sectional view of the duplexer 1 of the present embodiment. As shown in FIG. 3, the duplexer 1 includes a wiring board 40, a transmission-side surface acoustic wave filter chip 20A, and a reception-side surface acoustic wave filter chip 30A (or 30B) (illustrated in FIG. 3). For the sake of convenience, the filter chips 20A and 30A (or 30B) are drawn as one.) The transmission-side surface acoustic wave filter chip 20A and the reception-side surface acoustic wave filter chip 30A (or 30B) are flip-chip mounted by bumps on the die attach surface 40a of the wiring board 40. A sealing resin is formed on the wiring substrate 40 so as to cover the transmission-side surface acoustic wave filter chip 20A and the reception-side surface acoustic wave filter chip 30A (or 30B). That is, the duplexer 1 of the present embodiment is a CSP (Chip Size Package) type surface acoustic wave filter device. When the RFIC connected to the duplexer is an unbalanced input type, the reception-side surface acoustic wave filter chip 30A is mounted on the wiring board 40. When the RFIC connected to the duplexer is a balanced input type, the reception-side surface acoustic wave filter chip 30 </ b> B is mounted on the wiring board 40.

  As shown in FIG. 3, the wiring board 40 is configured by a laminated body of first to third dielectric layers 41 to 43 and first to fourth electrode layers 44 to 47. The first electrode layer 44 is disposed under the first dielectric layer 41. The second electrode layer 45 is disposed between the first dielectric layer 41 and the second dielectric layer 42. The third electrode layer 46 is disposed between the second dielectric layer 42 and the third dielectric layer 43. The fourth electrode layer 47 is disposed on the third dielectric layer 43. The wiring board 40 is a laminated board formed by alternately laminating electrode layers and dielectric layers. The first to fourth electrode layers 44 to 47 are connected by via hole electrodes formed on the first to third dielectric layers 41 to 43.

  Each of the first to third dielectric layers 41 to 43 can be made of, for example, a resin or ceramics such as alumina. That is, the wiring board 40 may be a printed wiring multilayer board made of resin or a ceramic multilayer board.

  In the present embodiment, an example will be described in which the wiring board is formed of a laminate of three dielectric layers and four electrode layers. However, the present invention is not limited to this configuration. In the present invention, the wiring board may have a single-layer dielectric or two or more dielectric layers.

  In the duplexer 1, a portion of the transmission filter 20 excluding the inductors L <b> 2 and L <b> 3 (the upper broken line portion in FIGS. 1 and 2) is formed on the transmission-side surface acoustic wave filter chip 20 </ b> A. In the duplexer 1, the antenna terminal 11, the transmission terminal 12, the reception terminals 13, 13 a, 13 b, and the inductors L 2, L 3 are formed on the wiring board 40. In the duplexer 1, the reception filter 30a (the lower broken line portion in FIG. 1) is formed on the reception-side surface acoustic wave filter chip 30A, and the reception filter 30b (the lower broken line portion in FIG. 2) is the reception side. It is formed on the surface acoustic wave filter chip 30B.

  Hereinafter, the transmission-side surface acoustic wave filter chip 20A and the reception-side surface acoustic wave filter chips 30A and 30B of the duplexer 1 of the present embodiment will be described.

  FIG. 4 is a schematic plan view of the transmission-side surface acoustic wave filter chip 20A and the reception-side surface acoustic wave filter chip 30A of the duplexer 1 of the present embodiment when the RFIC connected to the duplexer is an unbalanced input type. It is.

  The transmission-side surface acoustic wave filter chip 20A has a rectangular piezoelectric substrate. As shown in FIG. 4, series arm resonators S1 to S4, parallel arm resonators P1 to P3, and a plurality of pads 27a to 27f are formed on a piezoelectric substrate. Bumps are formed on the pads 27a to 27f.

  Each of the surface acoustic wave resonators constituting the series arm resonators S1 to S4 and the parallel arm resonators P1 to P3 has one IDT electrode and one set of the IDT electrode disposed on both sides of the surface acoustic wave propagation direction. And a reflector. That is, the surface acoustic wave resonators constituting the series arm resonators S1 to S4 and the parallel arm resonators P1 to P3 are one-port type surface acoustic wave resonators.

  The pad 27a is connected to the series arm resonator S1. The pad 27a functions as the output terminal 21. The pad 27b is connected to the parallel arm resonator P1. The pad 27c is connected to the parallel arm resonators P2 and P3. The pad 27d is connected to the series arm resonators S2 and S3. The pad 27e is a dummy pad and is electrically independent. The pad 27f is connected to the series arm resonator S4. The pad 27f functions as the input terminal 22.

  The reception-side surface acoustic wave filter chip 30A has a rectangular piezoelectric substrate. As shown in FIG. 4, a surface acoustic wave resonator 33, first and second longitudinally coupled resonator type surface acoustic wave filter portions 34 and 35, and a plurality of pads 37a to 37f are formed on a piezoelectric substrate. ing. Bumps are formed on the pads 37a to 37f.

  The surface acoustic wave resonator 33 includes one IDT electrode and a pair of reflectors arranged on both sides of the IDT electrode in the surface acoustic wave propagation direction. That is, the surface acoustic wave resonator 33 is a one-port surface acoustic wave resonator.

  Each of the first and second longitudinally coupled resonator type surface acoustic wave filter units 34 and 35 includes three IDT electrodes and a pair of reflectors arranged on both sides of the surface acoustic wave propagation direction of the IDT electrodes. Have. The first and second longitudinally coupled resonator type surface acoustic wave filter units 34 and 35 are cascade-connected to each other.

  The pads 37 a and 37 b are connected to the surface acoustic wave resonator 33. The pads 37a and 37b function as the unbalanced input terminal 31. The pads 37c and 37d are connected to the first and second longitudinally coupled resonator type surface acoustic wave filter sections 34 and 35. The pads 37c and 37d are ground pads connected to the ground. The pad 37e is not connected to the first and second longitudinally coupled resonator type surface acoustic wave filter units 34 and 35, but is connected to the ground. The pad 37 f is connected to the second longitudinally coupled resonator type surface acoustic wave filter unit 35. The pad 37f functions as the unbalanced output terminal 32. The pads 37e and 37f are provided at line-symmetric positions. Specifically, the pads 37e and 37f are intended for the center line passing through the midpoint between two opposing sides (here, two short sides) of the rectangular piezoelectric substrate constituting the receiving-side surface acoustic wave filter chip 30A. It is provided at a line-symmetric position with respect to the axis.

  The reception-side surface acoustic wave filter chip has insulating patterns 36a and 36b. Two wirings cross each other through the insulating patterns 36a and 36b.

  FIG. 5 is a schematic plan view of the transmission-side surface acoustic wave filter chip 20A and the reception-side surface acoustic wave filter chip 30B of the duplexer 1 of this embodiment when the RFIC connected to the duplexer is a balanced input type. is there. The transmission-side surface acoustic wave filter chip 20A shown in FIG. 5 is the same as the transmission-side surface acoustic wave filter chip 20A shown in FIG.

  As shown in FIG. 5, the reception-side surface acoustic wave filter chip 30B has substantially the same configuration as the reception-side surface acoustic wave filter chip 30A. Specifically, the reception-side surface acoustic wave filter chip 30B has a piezoelectric substrate. A surface acoustic wave resonator 33, first and second longitudinally coupled resonator type surface acoustic wave filter portions 34a and 35a, and a plurality of pads 37a to 37d, 37e1 and 37f1 are formed on the piezoelectric substrate. Bumps are formed on the pads 37a to 37d, 37e1, and 37f1.

  The surface acoustic wave resonator 33 is a one-port type surface acoustic wave resonator. Each of the first and second longitudinally coupled resonator type surface acoustic wave filter units 34a and 35a includes three IDT electrodes and a pair of reflectors arranged on both sides of the surface acoustic wave propagation direction of the IDT electrodes. Have. The first and second longitudinally coupled resonator type surface acoustic wave filter units 34a and 35a are cascade-connected to each other. Here, although two longitudinally coupled resonator type surface acoustic wave filters connected in cascade are used, the surface acoustic wave filter unit may be one longitudinally coupled resonator type surface acoustic wave filter. The surface acoustic wave filter unit may be a surface acoustic wave filter unit in which a plurality of longitudinally coupled resonator type surface acoustic wave filters are connected in parallel. That is, as long as the surface acoustic wave filter unit functions as a bandpass filter, the number and connection structure of the longitudinally coupled resonator type surface acoustic wave filters constituting the surface acoustic wave filter unit are not limited.

  The pads 37 a and 37 b are connected to the surface acoustic wave resonator 33. The pads 37a and 37b function as the unbalanced input terminal 31. The pads 37c and 37d are connected to the first and second longitudinally coupled resonator type surface acoustic wave filter portions 34a and 35a. The pads 37c and 37d are ground pads connected to the ground. The pad 37e1 is connected to the second longitudinally coupled resonator type surface acoustic wave filter part 35a. The pad 37e1 functions as the second balanced output terminal 32b. The pad 37f1 is connected to the second longitudinally coupled resonator type surface acoustic wave filter portion 35a. The pad 37f1 functions as the first balanced output terminal 32a.

  The reception-side surface acoustic wave filter chip 30B has an insulating pattern 36c. The two wirings intersect with each other via the insulating pattern 36c.

  The reception-side surface acoustic wave filter chip 30A and the reception-side surface acoustic wave filter chip 30B differ in the following points.

  Since the reception filter 30a is an unbalanced input-unbalanced output type filter, in the reception-side surface acoustic wave filter chip 30A, the second longitudinally coupled resonator type surface acoustic wave filter unit 35 is connected only to the pad 37f. ing. Specifically, among the three IDT electrodes of the second longitudinally coupled resonator type surface acoustic wave filter unit 35, the IDT electrode located at the center is connected to the pad 37f.

  On the other hand, since the reception filter 30b is an unbalanced input-balanced output type filter, in the reception-side surface acoustic wave filter chip 30B, the second longitudinally coupled resonator type surface acoustic wave filter unit 35a includes two pads 37e1, 37f1. Specifically, among the three IDT electrodes of the second longitudinally coupled resonator-type surface acoustic wave filter unit 35a, the IDT electrode located at the center is one of a pair of comb-like electrodes constituting the IDT electrode. It is composed of two divided comb-like electrodes. One divided comb-like electrode is connected to the pad 37e1, and the other divided comb-like electrode is connected to the pad 37f1.

  As described above, the reception-side surface acoustic wave filter chip 30B includes the configuration of the second longitudinally coupled resonator type surface acoustic wave filter unit and the connection structure between the second longitudinally coupled resonator type surface acoustic wave filter unit and the pad. Is different from the receiving surface acoustic wave filter chip 30A. Other configurations are the same. Therefore, the pads 37e1 and 37f1 of the unbalanced input-balanced output type reception-side surface acoustic wave filter chip 30B are the pads 37e and 37f of the unbalanced input-unbalanced output type reception-side surface acoustic wave surface acoustic wave filter chip 30A. And the arrangement is the same. That is, the arrangement of the pads 37e1 and 37f1 with respect to the pads 37a and 37b is the same as the arrangement of the pads 37e and 37f with respect to the pads 37a and 37b.

Below, the wiring board 40 of the duplexer 1 of this Embodiment is demonstrated.
FIG. 6 is a schematic perspective plan view of the fourth electrode layer 47 and the third dielectric layer 43 of the wiring board 40 in the duplexer 1 according to the present embodiment. FIG. 7 is a schematic perspective plan view of the third electrode layer 46 and the second dielectric layer 42 of the wiring board 40 in the duplexer 1 according to the present embodiment. FIG. 8 is a schematic perspective plan view of the second electrode layer 45 and the first dielectric layer 41 of the wiring board 40 in the duplexer 1 according to the present embodiment. FIG. 9 is a schematic perspective plan view of the first electrode layer 44 of the wiring board 40 in the duplexer 1 according to the present embodiment. 6 to 9 show a state in which the wiring substrate 40 is seen through from the side on which the transmission-side surface acoustic wave filter chip 20A and the reception-side surface acoustic wave filter chips 30A and 30B are mounted.

  As shown in FIG. 6, the fourth electrode layer 47 is composed of land electrodes 47a to 47l. The fourth electrode layer 47 is a land electrode layer. The land electrodes 47a to 47l are formed on the die attach surface 40a of the wiring substrate 40, and are connected to the pads of the transmission-side surface acoustic wave filter chip 20A and the pads of the reception-side surface acoustic wave filter chips 30A and 30B via bumps. Has been. In FIG. 6, regions where the transmission-side surface acoustic wave filter chip 20A and the reception-side surface acoustic wave filter chips 30A and 30B are mounted are indicated by broken lines. As shown in FIG. 7, the third electrode layer 46 includes electrodes 46 a to 46 i. As shown in FIG. 8, the second electrode layer 45 is composed of electrodes 45a to 45g. As shown in FIG. 9, the first electrode layer 44 is composed of electrodes 44a to 44i. The first electrode layer 44 is formed on the back surface 40 b of the wiring substrate 40. The first electrode layer 44 is a back terminal layer.

  The electrode 44 a of the first electrode layer 44 functions as the antenna terminal 11. The electrode 44 a is connected to the electrode 45 a of the second electrode layer 45 by the via hole electrode 51 a of the first dielectric layer 41. The via hole electrode 51a is two via hole electrodes. The electrode 45 a is connected to the electrode 46 a of the third electrode layer 46 by the via hole electrode 52 a of the second dielectric layer 42. The electrode 46 a is connected to the land electrodes 47 a, 47 b, 47 c of the fourth electrode layer 47 by via hole electrodes 53 a, 53 b, 53 c of the third dielectric layer 43. The land electrode 47a is connected to the pads 37a of the receiving surface acoustic wave filter chips 30A and 30B via bumps. The land electrode 47b is connected to the pads 37b of the receiving surface acoustic wave filter chips 30A and 30B via bumps. The land electrode 47c is connected to the pad 27a of the transmitting surface acoustic wave filter chip 20A via a bump.

  The electrode 44 b of the first electrode layer 44 functions as the transmission terminal 12. The electrode 44 b is connected to the electrode 45 b of the second electrode layer 45 by the via hole electrode 51 b of the first dielectric layer 41. The via hole electrode 51b is two via hole electrodes. The electrode 45 b is connected to the electrode 46 b of the third electrode layer 46 by the via hole electrode 52 b of the second dielectric layer 42. The electrode 46 b is connected to the land electrode 47 d of the fourth electrode layer 47 by the via hole electrode 53 d of the third dielectric layer 43. The land electrode 47d is connected to the pad 27f of the transmitting surface acoustic wave filter chip 20A via a bump.

  The electrode 44c of the first electrode layer 44 functions as the reception terminal 13 when the reception-side surface acoustic wave filter chip 30A is mounted on the wiring substrate 40, and the reception-side surface acoustic wave filter chip 30B is provided on the wiring substrate 40. When mounted, it functions as the first receiving terminal 13a. The electrode 44 c is connected to the electrode 45 c of the second electrode layer 45 by the via hole electrode 51 c of the first dielectric layer 41. The electrode 45 c is connected to the electrode 46 c of the third electrode layer 46 by the via hole electrode 52 c of the second dielectric layer 42. The electrode 46 c is connected to the land electrode 47 e of the fourth electrode layer 47 by the via hole electrode 53 e of the third dielectric layer 43. The land electrode 47e is connected to the pad 37f via a bump when the receiving-side surface acoustic wave filter chip 30A is mounted on the wiring board 40, and the receiving-side surface acoustic wave filter chip 30B is mounted on the wiring board 40. In such a case, the pad 37f1 is connected via a bump. The electrode 44c of the first electrode layer 44 constitutes a “first electrode”.

  The electrodes 44d, 44f, and 44g of the first electrode layer 44 function as ground terminals. The electrodes 44d, 44f, 44g are connected to the electrode 45d of the second electrode layer 45 by via hole electrodes 51d, 51e, 51f of the first dielectric layer 41. The electrode 45 d is connected to the electrodes 46 d and 46 i of the third electrode layer 46 by via hole electrodes 52 d and 52 e of the second dielectric layer 42. The via hole electrode 52d is ten via hole electrodes. The electrode 46 d is connected to the land electrodes 47 f and 47 g of the fourth electrode layer 47 by via hole electrodes 53 f and 53 g of the third dielectric layer 43. The electrode 46 i is connected to the land electrode 47 h of the fourth electrode layer 47 by a via hole electrode 53 h of the third dielectric layer 43. The land electrode 47f is connected to the pads 37c of the receiving surface acoustic wave filter chips 30A and 30B via bumps. The land electrode 47g is connected to the pads 37d of the receiving surface acoustic wave filter chips 30A and 30B via bumps. The land electrode 47h is connected to the pad 27e of the transmission-side surface acoustic wave filter chip 20A via a bump.

  The electrode 44h of the first electrode layer 44 functions as a ground terminal. The electrode 44 h is connected to the electrode 45 f of the second electrode layer 45 by a via hole electrode 51 g of the first dielectric layer 41. The electrode 45 f is connected to the electrode 46 f of the third electrode layer 46 by the via hole electrode 52 f of the second dielectric layer 42. The electrode 46 f is connected to the land electrode 47 i of the fourth electrode layer 47 by the via hole electrode 53 i of the third dielectric layer 43. The land electrode 47i is connected to the pad 27b of the transmitting surface acoustic wave filter chip 20A via a bump. The electrodes 45f, 46f, 47i and the via hole electrodes 51g, 52f, 53i constitute an inductor L2.

  The electrode 44i of the first electrode layer 44 functions as a ground terminal. The electrode 44 i is connected to the electrode 45 g of the second electrode layer 45 by the via hole electrode 51 h of the first dielectric layer 41. The electrode 45g is connected to the electrode 46g of the third electrode layer 46 by the via hole electrode 52g of the second dielectric layer 42. The electrode 46 g is connected to the land electrode 47 j of the fourth electrode layer 47 by the via hole electrode 53 j of the third dielectric layer 43. The land electrode 47j is connected to the pad 27c of the transmitting surface acoustic wave filter chip 20A via a bump. The electrodes 45g, 46g, 47j and the via hole electrodes 51h, 52g, 53j constitute an inductor L3.

  The electrode 46h of the third electrode layer 46 is a floating electrode. Therefore, the electrode 46h is connected to the land electrode 47k of the fourth electrode layer 47 by the via hole electrode 53k of the third dielectric layer 43, but the electrodes 45a to 45g of the second electrode layer 45 and It is not connected to any of the electrodes 44 a to 44 i of the first electrode layer 44. The land electrode 47k is connected to the pad 27d of the transmitting surface acoustic wave filter chip 20A via a bump.

  The electrode 44e of the first electrode layer 44 functions as a ground terminal when the receiving-side surface acoustic wave filter chip 30A is mounted on the wiring substrate 40, and the receiving-side surface acoustic wave filter chip 30B is mounted on the wiring substrate 40. If it is, it functions as the second receiving terminal 13b. The electrode 44 e is connected to the electrode 45 e of the second electrode layer 45 by the via hole electrode 51 i of the first dielectric layer 41. The electrode 45e is connected to the electrode 46e of the third electrode layer 46 by a via hole electrode 52h of the second dielectric layer 42. The electrode 46 e is connected to the land electrode 47 l of the fourth electrode layer 47 by the via hole electrode 53 l of the third dielectric layer 43. When the reception-side surface acoustic wave filter chip 30A is mounted on the wiring substrate 40, the land electrode 47l is connected to the pad 37e via a bump, and the reception-side surface acoustic wave filter chip 30B is mounted on the wiring substrate 40. In that case, it is connected to the pad 37e1 via a bump. The electrode 44e of the first electrode layer 44 constitutes a “second electrode”.

  As a comparative example for the duplexer 1, when the RFIC connected to the duplexer is an unbalanced input type, a duplexer in which a receiving surface acoustic wave filter chip 30C different from the receiving surface acoustic wave filter chip 30A is mounted on a wiring board is provided. Produced. In the duplexer of the comparative example, when the RFIC connected to the duplexer is an unbalanced input type, the reception-side surface acoustic wave filter chip 30C is mounted on the wiring board. The reception-side surface acoustic wave filter chip 30C is different in the connection method between the reception-side surface acoustic wave filter chip 30A, the second longitudinally coupled resonator-type surface acoustic wave filter section, and the pad.

  FIG. 10 is a schematic plan view of the transmission-side surface acoustic wave filter chip 20A and the reception-side surface acoustic wave filter chip 30C of the duplexer of the comparative example.

  As shown in FIG. 10, the transmission-side surface acoustic wave filter chip 20A of the duplexer of the comparative example is the same as the transmission-side surface acoustic wave filter chip 20A of the duplexer 1 shown in FIGS.

  As shown in FIG. 10, in the receiving-side surface acoustic wave filter chip 30C of the duplexer of the comparative example, not only the pad 37f but also the pad 37e2 is connected to the second longitudinally coupled resonator type surface acoustic wave filter unit 35. The pad 37e2 and the pad 37f have the same configuration as the receiving surface acoustic wave filter chip 30A of the duplexer 1 shown in FIG. 4 except that both the pad 37e2 and the pad 37f function as the unbalanced output terminal 32.

  11 to 14 show a wiring board of a duplexer of a comparative example. As shown in FIGS. 11 to 14, in the wiring board of the duplexer of the comparative example, the electrode 44e1 of the first electrode layer 44 is shown in FIGS. 6 to 9 except that it functions as the receiving terminal 13 together with the electrode 44c. It has the same configuration as the wiring board 40 of the duplexer 1.

  Here, the electrical characteristics of the reception filter in each of the duplexer 1 according to the present embodiment and the duplexer of the comparative example were measured. In the duplexer 1, the reception-side surface acoustic wave filter chip 30 </ b> A is mounted on the wiring board 40.

  The duplexer 1 according to the present embodiment was measured using the measurement substrate shown in FIG. The duplexer of the comparative example was measured using the measurement substrate shown in FIG. The difference in the measurement substrate used between the duplexer 1 according to the present embodiment and the duplexer according to the comparative example is that the function of the electrode of the first electrode layer 44 of the wiring substrate 40 is different. Specifically, in the duplexer 1 according to the present embodiment, only the electrode 44c of the first electrode layer 44 functions as the receiving terminal 13, while in the duplexer of the comparative example, the electrode 44e1 of the first electrode layer 44 is used. Since the electrode 44c functions as the receiving terminal 13, the same signal is output from the electrode 44e1 and the electrode 44c. For this reason, it is necessary to combine the two signals output from the electrodes 44e1 and 44c into one. Therefore, when measuring the filter characteristics of the reception filter of the duplexer of the comparative example, it is necessary to use a measurement board on which wiring for synthesizing two signals output from the electrodes 44e1 and 44c into one is used. There is.

  FIG. 16 shows the pass characteristics of the reception filter in each of the duplexer 1 according to the present embodiment and the duplexer of the comparative example. As illustrated in FIG. 16, the reception filter of the duplexer 1 according to the present embodiment has a smaller insertion loss in the pass band (869 MHz to 894 MHz) of the reception filter than the reception filter of the duplexer of the comparative example. Further, the reception filter of the duplexer 1 according to the present embodiment has a larger attenuation in the pass band (824 MHz to 849 MHz) of the transmission filter than the reception filter of the duplexer of the comparative example.

  17 shows the V.V. of the reception filter in each of the duplexer 1 according to the present embodiment and the duplexer of the comparative example. S. W. R (Voltage Standing Wave Ratio) is shown. As illustrated in FIG. 17, the reception filter of the duplexer 1 according to the present embodiment has a V.V. in the reception filter pass band (869 MHz to 894 MHz), more than the reception filter of the duplexer of the comparative example. S. W. R is small.

  In the duplexer of the comparative example, the same signal is output from the electrode 44e1 and the electrode 44c of the first electrode layer 44 functioning as the receiving terminal 13, so that wiring for combining two signals of the measurement board into one, etc. Including, the path through which the received signal flows is long. For this reason, the influence of the resistance and parasitic capacitance due to the wiring is increased. As a result, in the reception filter of the duplexer of the comparative example, insertion loss or V.V. in the pass band (869 MHz to 894 MHz) of the reception filter is obtained. S. W. R increases. On the other hand, in the duplexer 1 according to the present embodiment, since a signal is output only from the electrode 44c of the first electrode layer 44 functioning as the reception terminal 13, the path through which the reception signal flows is short. For this reason, the influence of resistance and parasitic capacitance due to the wiring is reduced. Therefore, in the duplexer 1 according to the present embodiment, the insertion loss or V.V. in the pass band (869 MHz to 894 MHz) of the reception filter. S. W. R is small.

  As described above, in the duplexer 1 according to the present embodiment, when the surface acoustic wave filter chip is an unbalanced input-unbalanced output type, the electrodes that function as the receiving terminal 13 are integrated into one (FIG. 9). Therefore, even when the surface acoustic wave filter chip is of the unbalanced input-balanced output type, it is possible to cope with the same package and suppress insertion loss.

  The above contents are summarized as follows. That is, in the duplexer 1 (demultiplexer) according to the present embodiment, the reception-side filter is either an unbalanced input-unbalanced output type (reception filter 30a) or an unbalanced input-balanced output type (reception filter 30b). This is a surface acoustic wave device having a structure that can cope with the above-described case. When manufacturing such a surface acoustic wave device, first, as an unbalanced input-balanced output type filter, a first piezoelectric substrate and a first unbalanced input terminal formed on the first piezoelectric substrate ( Pads 37a, 37b) and two balanced output terminals (pads 37e1, 37f1), and a first surface acoustic wave connected between the first unbalanced input terminal and the first and second balanced output terminals. A first surface acoustic wave filter chip (reception-side surface acoustic wave filter chip 30B) having a filter unit (first and second longitudinally coupled resonator type surface acoustic wave surface acoustic wave filter units 34a and 35a) is prepared. . Further, as an unbalanced input-unbalanced output type filter, a second piezoelectric substrate, a second unbalanced input terminal (pads 37a and 37b) formed on the second piezoelectric substrate, and an unbalanced output terminal ( A second surface acoustic wave having a pad 37f1), a ground terminal (pad 37e1), and a second surface acoustic wave filter portion connected between the second unbalanced input terminal and the unbalanced output terminal. A filter chip (reception-side surface acoustic wave filter chip 30A) is prepared. Here, the arrangement of the unbalanced output terminal and the ground terminal with respect to the second unbalanced input terminal of the second surface acoustic wave filter chip is the first with respect to the first unbalanced input terminal of the first surface acoustic wave filter chip. And the arrangement of the second balanced output terminals is the same. Further, a substrate body having a surface (die attach surface 40a) and a back surface (back surface 40b) facing each other, a first land electrode (land electrodes 47a and 47b), a second land electrode provided on the surface (Land electrode 47e) and third land electrode (land electrode 47l), and first to third back terminals (provided on the back surface and connected to the first to third land electrodes, respectively) A wiring board (wiring board 40) having back terminals 44a, 44c, 44e) is prepared. Then, the first surface acoustic wave filter chip or the second surface acoustic wave filter chip is flip-chip mounted on the surface of the wiring board. Here, when the first surface acoustic wave filter chip is mounted on the wiring board, the first unbalanced input terminal is the first land electrode, the first balanced output terminal is the second land electrode, Two balanced output terminals are respectively connected to the third land electrodes. When the second surface acoustic wave filter chip is mounted on the wiring board, the second unbalanced input terminal is the first land electrode, the unbalanced output terminal is the second land electrode, and the ground terminal is the first. 3 land electrodes. Thereby, the unbalanced input-balanced output type filter and the unbalanced input-unbalanced output type filter which can share the same wiring board can be manufactured.

  Although the embodiments of the present invention have been described above, the embodiments disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is defined by the terms of the claims, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

  DESCRIPTION OF SYMBOLS 1 Duplexer, 11 Antenna terminal, 12 Transmission terminal, 13, 13a, 13b Reception terminal, 20 Transmission filter, 20A Transmission side surface acoustic wave filter chip, 21 Output terminal, 22 Input terminal, 23 Series arm, 24-26 Parallel arm, 27a-27f, 37a-37d, 37e1, 37f1 pad, 30A, 30B, 30C reception side surface acoustic wave filter chip, 30a, 30b reception filter, 31 unbalanced input terminal, 32 unbalanced output terminal, 32a, 32b balanced output terminal 33, surface acoustic wave resonators, 34, 34a, 35, 35a surface acoustic wave filter sections, 36a, 36b, 36c insulating patterns, 40 wiring boards, 40a die attach surfaces, 40b back surfaces, 41 to 43 dielectric layers, 44-47 electrode layers, 44a-44i, 45a-45g, 46a-4 i electrode, 47a~47l land electrode, 51a~53l via hole - Le electrode.

Claims (8)

A first piezoelectric substrate, a first unbalanced input terminal and first and second balanced output terminals formed on the first piezoelectric substrate, the first unbalanced input terminal, and the first And a first surface acoustic wave filter unit connected between the first balanced output terminal and the second balanced output terminal, or a first surface acoustic wave filter chip of an unbalanced input-balanced output type or a second piezoelectric substrate A second unbalanced input terminal, an unbalanced output terminal, and a ground terminal formed on the second piezoelectric substrate, and between the second unbalanced input terminal and the unbalanced output terminal. A second surface acoustic wave filter unit connected to the second unbalanced input terminal, wherein the unbalanced output terminal and the ground terminal are arranged with respect to the first unbalanced input terminal. And the same arrangement as the second balanced output terminal A step of preparing an unbalanced output type of the second surface acoustic wave filter chip, - there unbalanced input
A substrate main body having a front surface and a back surface facing each other, first to third land electrodes provided on the front surface, and provided on the back surface, and each of the first to third land electrodes. Preparing a wiring board having first to third back terminals connected thereto;
Flip-chip mounting the first surface acoustic wave filter chip or the second surface acoustic wave filter chip on the surface of the wiring board,
When the first surface acoustic wave filter chip is mounted on the wiring board, the first unbalanced input terminal is used as the first land electrode, and the first balanced output terminal is used as the second land electrode. And connecting the second balanced output terminal to the third land electrode,
When the second surface acoustic wave filter chip is mounted on the wiring board, the second unbalanced input terminal is the first land electrode, the unbalanced output terminal is the second land electrode, A method of manufacturing a surface acoustic wave device, wherein the ground terminal is connected to the third land electrode.   The method of manufacturing a surface acoustic wave device according to claim 1, wherein the surface acoustic wave filter unit is configured by a longitudinally coupled resonator type surface acoustic wave filter.   The method for manufacturing a surface acoustic wave device according to claim 1, wherein the second and third back terminals are adjacent to each other on the back surface.   The surface acoustic wave device is a duplexer including a transmission filter and a reception filter, and the first or second surface acoustic wave filter chip is the reception filter. A method for producing the surface acoustic wave device according to claim. A rectangular piezoelectric substrate, an unbalanced input terminal formed on the piezoelectric substrate, an unbalanced output terminal, and a ground terminal, and an elasticity connected between the unbalanced input terminal and the unbalanced output terminal An unbalanced input-unbalanced output type surface acoustic wave filter chip having a surface wave filter section;
A substrate main body having a front surface and a back surface facing each other, first to third land electrodes provided on the front surface, and provided on the back surface, and each of the first to third land electrodes. A wiring board having first to third back terminals connected to each other,
The unbalanced output terminal and the ground terminal are arranged line-symmetrically on the piezoelectric substrate,
The second unbalanced input terminal is connected to the first land electrode, the unbalanced output terminal is connected to the second land electrode, and the ground terminal is connected to the third land electrode. Wave equipment.   The surface acoustic wave device according to claim 5, wherein the surface acoustic wave surface acoustic wave filter unit includes a longitudinally coupled resonator type surface acoustic wave surface acoustic wave filter.   The surface acoustic wave device according to claim 5 or 6, wherein the second and third back terminals are adjacent to each other on the back surface.   The surface acoustic wave device according to any one of claims 5 to 7, wherein the surface acoustic wave device includes a transmission filter and a reception filter, wherein the acoustic wave filter chip is a reception filter of the branching filter.

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