An elastic wave device includes resonators having a piezoelectric substrate, a resonation unit formed on the piezoelectric substrate, and reflectors formed on respective sides of the resonation unit on the piezoelectric substrate, and bumps formed on the piezoelectric substrate. The resonators are configured such that two or more split resonators are connected in parallel, and a bump is formed in a region sandwiched between reflectors of the split resonators.
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0. 30. A duplexer comprising:
a transmission filter; and
a reception filter having a pass frequency band different from that of the transmission filter,
wherein at least one of the transmission filter and the reception filter is the filter according to claim 29.
0. 20. A duplexer comprising:
a transmission filter; and
a reception filter having a pass frequency band different from that of the transmission filter,
wherein at least one of the transmission filter and the reception filter is the filter according to claim 19.
0. 15. A duplexer comprising:
a transmission filter; and
a reception filter having a pass frequency band different from that of the transmission filter,
wherein at least one of the transmission filter and the reception filter is the filter according to claim 14.
0. 25. A duplexer comprising:
a transmission filter; and
a reception filter having a pass frequency band different from that of the transmission filter,
wherein at least one of the transmission filter and the reception filter is the filter according to claim 24.
0. 12. An elastic wave device comprising:
a resonator configured to have two or more split resonators formed on a piezoelectric substrate; and
a bump formed on the piezoelectric substrate,
wherein said two or more split resonators are connected in parallel, and the bump is formed in a region sandwiched between the split resonators and is electrically and acoustically separated from the split resonators.
0. 22. An elastic wave device comprising:
a plurality of resonators on a piezoelectric substrate, the plurality of resonators including two or more split resonators each having a pair of comb-shaped electrodes; and
a bump formed on the piezoelectric substrate,
wherein said two or more split resonators are connected in parallel, and the bump is formed in a region sandwiched between the split resonators and is electrically and acoustically separated from said comb-shaped electrodes of the split resonators.
1. An elastic wave device comprising:
a resonator having a piezoelectric substrate, a resonation unit formed on the piezoelectric substrate, and reflectors formed on respective sides of the resonation unit on the piezoelectric substrate; and
a bump formed on the piezoelectric substrate,
wherein the resonator is configured such that two or more split resonators are connected in parallel, and the bump is formed in a region sandwiched between reflectors of the split resonators and is electrically and acoustically separated from the resonator.
0. 17. An elastic wave device comprising:
a resonator configured to have two or more split resonators, the split resonators each having a resonation unit formed on a piezoelectric substrate and reflectors formed on respective sides of the resonation unit on the piezoelectric substrate; and
a bump formed on the piezoelectric substrate,
wherein said two or more split resonators are connected in parallel, and the bump is formed in a region sandwiched between reflectors of the split resonators and is electrically and acoustically separated from the resonation unit of the respective split resonators.
0. 27. An elastic wave device comprising:
a plurality of resonators on a piezoelectric substrate, the plurality of resonators each having a pair of comb-shaped electrodes, the plurality of resonators including two or more split resonators each having a pair of comb-shaped electrodes; and
a bump formed on the piezoelectric substrate,
wherein said two or more split resonators are connected in parallel, and the bump is formed in a region sandwiched between the split resonators and is electrically and acoustically separated from said comb-shaped electrodes of any of the resonators that are adjacent to the bump.
0. 32. An elastic wave device comprising:
a resonator having first and second signal wiring patterns on a surface of a piezoelectric substrate, the resonator having two split resonators arranged side-by-side with each other on the surface of the piezoelectric substrate, the two split resonators being disposed between, and each connected to, the first and second signal wiring patterns so as to be connected in parallel with each other between the first and second signal wiring patterns; and
a bump formed on a metal island on the surface of the piezoelectric substrate,
wherein the metal island having the bump thereon is disposed in a region on the surface of the piezoelectric substrate sandwiched between the two split resonators and surrounded by the first and second signal wiring patterns and the two split resonators, and is not connected to, and therefore is separated from, any of the two split resonators and the first and second signal wiring patterns on the surface of the piezoelectric substrate so that the bump on the metal island is electrically and acoustically separated from the two split resonators on the surface of the piezoelectric substrate.
2. The elastic wave device according to
wherein the bump is surrounded by the signal wiring and the reflectors.
5. The elastic wave device according to
6. The elastic wave device according to
8. A filter comprising the elastic wave device according to
9. A duplexer comprising:
a transmission filter; and
a reception filter having a pass frequency band different from that of the transmission filter,
wherein at least one of the transmission filter and the reception filter is configured using the filter according to
10. A communication apparatus comprising:
an antenna;
the duplexer according to
0. 11. The elastic wave device according to claim 1, wherein there is no bump other than said bump in said region sandwiched between the reflectors of the split resonators.
0. 13. The elastic wave device according to claim 12, wherein the bump is connected to a ground.
0. 14. A filter comprising the elastic wave device according to claim 12, wherein the elastic wave device includes a plurality of resonators connected to each other.
0. 16. The elastic wave device according to claim 12, wherein there is no bump other than said bump in said region sandwiched between the split resonators.
0. 18. The elastic wave device according to claim 17, wherein the bump is connected to a ground.
0. 19. A filter comprising the elastic wave device according to claim 17, wherein the elastic wave device includes a plurality of resonators connected to each other.
0. 21. The elastic wave device according to claim 17, wherein there is no bump other than said bump in said region sandwiched between the reflectors of the split resonators.
0. 23. The elastic wave device according to claim 22, wherein the bump is connected to a ground.
0. 24. A filter comprising the elastic wave device according to claim 22, wherein the elastic wave device includes a plurality of resonators connected to each other.
0. 26. The elastic wave device according to claim 22, wherein there is no bump other than said bump in said region sandwiched between the split resonators.
0. 28. The elastic wave device according to claim 27, wherein the bump is connected to a ground.
0. 29. A filter comprising the elastic wave device according to claim 27, wherein the elastic wave device includes a plurality of resonators connected to each other.
0. 31. The elastic wave device according to claim 27, wherein there is no bump other than said bump in said region sandwiched between the split resonators.
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This application is based upon and claims the benefit of priority of the prior International Patent Application No. PCT/JP2007/072161, filed on Nov. 15, 2007 the entire contents of which are incorporated herein by reference.
The present invention relates to an elastic wave device having an elastic wave resonator, and for example an elastic wave device having a high power durability, a duplexer using the same, and a communication apparatus using the duplexer.
An elastic wave resonator has comb-shaped electrodes that have been formed from an aluminum alloy, a Cu alloy, or the like on a piezoelectric substrate, a piezoelectric thin film, or the like and that have a period corresponding to a predetermined frequency, and the elastic wave resonator makes use of elastic waves excited by the comb-shaped electrodes. The comb-shaped electrode is called IDT (Interdigital transducer). Examples of elastic waves excited by comb-shaped electrodes are surface acoustic waves and elastic boundary waves. For example, in the case of a 1 port resonator, a dual resonance characteristic of having a resonance frequency and an antiresonance frequency is exhibited. An example of a circuit employing this characteristic is a ladder filter in which 1 port resonators that have different comb-shaped electrode periods are disposed in series arms and parallel arms to form a ladder shape (e.g., see Patent Document 1). Other examples include a DMS (Double mode SAW (Surface Acoustic Wave)) filter in which a resonator is formed by a plurality of comb-shaped electrodes, and an IIDT (Interdigitated IDT) filter that has excitation comb-shaped electrodes and reception comb-shaped electrodes.
A ladder filter is used in a duplexer connected to an antenna of a communication apparatus. Accordingly, particularly in the case of a transmission ladder filter, there is demand for power durability due to being directly subjected to the power transmitted to the antenna. In a ladder filter, a first method of raising the power durability by design involves suppressing the occurrence of migration by raising the ability of the device to exhaust heat and lowering the temperature of the device.
Heat is exhausted from the piezoelectric substrate by allowing the heat to escape to a connection substrate mainly via a package or the like. In a conventional configuration, as illustrated in the top view of
Also, a reduced-size package has, as illustrated in the top view of
Also, a second method of improving the power durability involves increasing the number of pairs (number of comb-shaped electrodes) per resonator.
However, problems such as the following exist in the conventional filters described above. With the first method for raising the power durability, the heat conductivity per bump is good since gold is used, but the number of heat exhaust paths is reduced, and the temperature of the filter rises. For this reason, in order to efficiently exhaust heat, it is important to dispose the bumps beside the heat generating elements (comb-shaped electrodes).
Also, with the second method for raising the power durability, the size of the resonator itself increases, thus having the problem that the device size increases. Also, since the regions where a bump can be disposed are separated from the center of the heat generating elements, there are problems such as a weakening of the effect of exhausting heat via the bumps.
An elastic wave device disclosed in this application includes: a resonator having a piezoelectric substrate, a resonation unit formed on the piezoelectric substrate, and reflectors formed on respective sides of the resonation unit on the piezoelectric substrate; and a bump formed on the piezoelectric substrate. The resonator is configured such that two or more split resonators are connected in parallel, and the bump is formed in a region sandwiched between reflectors of the split resonators.
The object and advantages of the invention will be realized and attained by means of the elements and combinations particularly pointed out in the appended claims. It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the invention, as claimed.
1 ladder filter
2 input terminal
3 output terminal
4 first-stage filter
5 second-stage filter
6 third-stage filter
11, 21, 31, 51 piezoelectric substrate
12 input bump
13 output bump
14, 15, 16 ground bump
22, 32, 33, 52 resonation unit
23a, 34a, 34b first bus bar
23b, 37a, 37b second bus bar
24a, 35a, 35b first comb-shaped electrode
24b, 38a, 38b second comb-shaped electrode
25a, 36a, 36b first excitation electrode
25b, 39a, 39b second excitation electrode
26a, 26b reflector
27a, 27b, 44, 47a, 47b, 64 metal film
28a, 28b, 55, 56, 57, 65 bump
40a, 61 first signal wiring
40b, 63 second signal wiring
41a, 41b outer reflector
42a, 42b inner reflector
43 inner region where a bump can be formed
45 inner bump
46a, 46b outer region where a bump can be formed
48a, 48b outer bump
53, 54 leader wiring
62 ground bump
66 signal wiring bump
71 antenna
72 duplexer
73 transmission-side signal processing unit
74 reception-side signal processing unit
75 microphone
76 speaker
77 transmission filter
78 reception filter
S1 combined series resonator
S11, P11 first split resonator
S12, P12 second split resonator
S2, S3 series resonator
P1, P2, P3 parallel resonator
The elastic wave device disclosed in this application is connected to a package or a connection substrate with use of a bump in order to receive a supply of power during use and in order for the position of the elastic wave device to be fixed. Since the bump is formed in a region sandwiched between the reflectors of the split resonators, heat generated by the split resonators is efficiently exhausted, and the power durability is improved over that in the case of using a non-split resonator.
Also, a configuration is possible in which the elastic wave device has signal wiring connected to the resonation unit, and the bump is surrounded by the signal wiring and the reflectors.
Also, a configuration is possible in which the bump is connected to a ground. Also, a configuration is possible in which the bump is connected to external wiring.
Also, a configuration is possible in which the split resonators each have the same number of pairs of comb-shaped electrodes. Due to forming the same number of pairs, the same amount of heat is generated by the split resonators, thus improving the efficiency with which heat is exhausted from the bump sandwiched between the reflectors of the split resonators.
Also, a configuration is possible in which, in each of the split resonators, comb-shaped electrodes are formed using the same design. According to this configuration, the split resonators each have the same resonance frequency and antiresonance frequency. Also, it is possible to prevent signals from becoming attenuated due to signal reflection and the like. Examples of “the same design” include the material, width, aperture length (length along which a comb-shaped electrode opposes another comb-shaped electrode), and number of the comb-shaped electrodes all being the same, with the exception of manufacturing error.
Also, a configuration is possible in which a material of the bump is Au. Using highly conductive Au enables improving the heat-exhaust efficiency.
A filter of the present embodiment has a plurality of resonators as the elastic wave device described above, and the plurality of resonators are connected.
This configuration enables raising the power durability. The filter can include the elastic wave device that has the plurality of resonators. At least one of the plurality of resonators includes at least two split resonators that are connected in parallel, and the bump is formed in a region sandwiched between the split resonators.
Also, a duplexer of the present embodiment includes: a transmission filter; and a reception filter having a pass frequency band different from that of the transmission filter, wherein at least one of the transmission filter and the reception filter is configured using the filter described above. This configuration enables improving the power durability of the filter, and at the same time improving the power durability of the duplexer as well.
Also, a communication apparatus of the present embodiment can have a configuration including: an antenna; the above-described duplexer that is connected to the antenna; and a signal processing unit connected to the duplexer. This configuration enables improving the power durability of the duplexer, and at the same time improving the power durability of the communication apparatus as well.
According to the preferred embodiment of present invention, resonator in the elastic wave device is split into at least two split resonators each having a halved number of pairs and a bump is provided between the split resonators of a resonator in which two split resonators are connected in parallel, thus enabling providing an elastic wave device having a high power durability in which the heat dissipation efficiency is increased without a change in capacitance, a duplexer using the same, and a communication apparatus using the duplexer.
The first-stage filter 4 has a combined series resonator S1 disposed in a series arm and a parallel resonator P1 disposed in a parallel arm. The second-stage filter 5 has a series resonator S2 disposed in a series arm and a parallel resonator P2 disposed in a parallel arm. The third-stage filter 6 has a series resonator S3 disposed in a series arm and a parallel resonator P3 disposed in a parallel arm. The combined series resonator S1 is formed by connecting a first split resonator S11 and a second split resonator S12 in parallel. The combined series resonator S1 includes the first split resonator S11 and the second split resonator S12. That is to say, combined series resonator S1 is split into two split resonator S11, S12.
The resonance frequency of the combined series resonator S1, the second series resonator S2 and the third series resonator S3 is frs, and the antiresonance frequency thereof is fas. The resonance frequency of the first parallel resonator P1, the second parallel resonator P2, and the third parallel resonator P3 is frp, and the antiresonance frequency thereof is fap. The resonance frequency frs of the series resonators and the antiresonance frequency fap of the parallel resonators are set so as to be substantially the same frequency, and the ladder filter 1 operates as a bandpass filter.
The first excitation electrode 25a is formed by connecting a plurality of first comb-shaped electrodes 24a to a first bus bar 23a. Likewise, the second excitation electrode 25b is formed by connecting a plurality of second comb-shaped electrodes 24b to a second bus bar 23b. The first excitation electrode 25a and the second excitation electrode 25b are disposed in opposition such that the first comb-shaped electrodes 24a and the second comb-shaped electrodes 24b alternate in a row. The reflectors 26a and 26b are formed on respective sides of the resonation unit 22 in a direction perpendicular to the lengthwise direction of the first comb-shaped electrodes 24a.
Metal films 27a and 27b are formed on sides of the reflectors 26a and 26b opposite from where the resonation unit 22 is formed. Bumps 28a and 28b are formed on the metal films 27a and 2′7b. The bumps 28a and 28b discharge heat generated in the resonation unit 22. In order to be used as heat conduction paths for such a purpose, such bumps are preferably provided close to the resonation unit 22, more specifically beside the reflectors 26a and 26b where disposition is possible. The bumps 28a and 28b are connected to the package, and are electrically connected to the resonation unit 22. However, a configuration in which the bumps 28a and 28b are not connected to the resonation unit 22 is also possible. Also, there is no need for the formation positions of the bumps 28a and 28b to be on the sides of the reflectors 26a and 26b opposite from the resonation unit 22, and the bumps 28a and 28b do not need to be provided if they are unnecessary.
The first excitation electrode 36a and the second excitation electrode 39a are disposed in opposition, and the first excitation electrode 36b and the second excitation electrode 39b are disposed in opposition, such that first comb-shaped electrodes 35a and second comb-shaped electrodes 38a alternate in a row, and first comb-shaped electrodes 35b and second comb-shaped electrodes 38b alternate in a row. In the first excitation electrode 36a, the first comb-shaped electrodes 35a are each connected to a first bus bar 34a. Likewise, in the second excitation electrode 39a, the second comb-shaped electrodes 38a are each connected to a second bus bar 37a. In the first excitation electrode 36b, the first comb-shaped electrodes 35b are each connected to a first bus bar 34b. Likewise, in the second excitation electrode 39b, the second comb-shaped electrodes 38b are each connected to a second bus bar 37b.
An inner region 43 where a bump can be formed is provided so as to be sandwiched between the inner reflectors 42a and 42b. A metal film 44 is formed in the inner region 43 where a bump can be formed, and an inner bump 45 is formed on the metal film 44. Also, outer regions 46a and 46b where a bump can be formed are provided on outer sides of the outer reflectors 41a and 41b. Metal films 47a and 47b are respectively formed in the outer regions 46a and 46b where a bump can be formed, and outer bumps 48a and 48b are respectively formed on the metal films 47a and 47b.
The inner bump 45 and the outer bumps 48a and 48b are connected to the package. Accordingly, heat generated by the first split resonator S11 and the second split resonator S12 is exhausted to the package via the inner bump 45 and the outer bumps 48a and 48b. The inner bump 45 and the outer bumps 48a and 48b are connected to a circuit (resonator). However, connection to a circuit is not necessary, and a configuration in which such bumps are electrically set-off from a circuit is also possible. Also, in the case in which the inner bump 45 and the outer bumps 48a and 48b are connected to a circuit, the inner bump 45 and the outer bumps 48a and 48b may be connected to external wiring or grounded. Also, there is no need for the formation positions of the outer bumps 48a and 48b to be on the sides of the outer reflectors 41a and 41b opposite from the resonation units 32 and 33. Also, the outer bumps 48a and 48b do not need to be provided if they are unnecessary.
The resonator illustrated in
As described above, splitting the resonator and providing an internal bump enables efficiently allowing heat generated by the resonators to escape to the package. As a result, the power durability rises without an increase in the temperature of the resonators.
In the combined parallel resonator illustrated in
A combined series resonator illustrated in
A combined series resonator illustrated in
A combined series resonator illustrated in
The combined resonators illustrated in
As described above, unlike conventional resonators, in the filter according to the present embodiment, resonators (split resonators) having a halved number of comb-shaped electrodes are connected in parallel, and a bump is formed at a position sandwiched between the reflectors of the split resonators, thus raising the heat dissipation efficiency and raising the power durability.
Note that although exemplary configurations of combined resonators are described in the present embodiment, the configuration of the combined resonator is not limited to such exemplary configurations, and any configuration is possible as long as an internal bump is formed so as to be sandwiched between split resonators. Also, a plurality of combined resonators may be disposed in the filter. Furthermore, although examples of configuring the combined resonator by two split resonators are described in the present embodiment, the combined resonator may be formed from three or more split resonators.
Also, in the ladder filter illustrated in
Also, although the split resonators may each have a different number of (number of pairs of) comb-shaped electrodes, the number of comb-shaped electrodes is preferably the same. As a result of causing the number of comb-shaped electrodes to be same, the same amount of heat is generated by the resonators. Accordingly, the position at which the internal bump is formed is a position enabling heat from the split resonators to be exhausted most efficiently. Also, the comb-shaped electrodes are preferably configured using the same design. Here, as one example of “the same design”, the material, width, aperture length (length along which a comb-shaped electrode opposes another comb-shaped electrode), and number of the comb-shaped electrodes are all the same between the split resonators. As a result of using the same design, the split resonators each have the same resonance frequency and antiresonance frequency. Also, using the same design enables preventing signals from being attenuated due to signal reflection and the like.
Also, although the filter has been described taking the example of a ladder filter in the present embodiment, the same effects can be obtained when a lattice filter is used.
Note that the combined resonator is not limited to being applied to a filter, and may be used as an elastic wave device in other applications.
Also, although exemplary configurations in which the filter is connected to the package using a face-down method have been described, there is no limitation to using a face-down method. The same heat-exhaust effect can be obtained in any configuration in which heat is exhausted by a bump.
The microphone 75 converts audio into an audio signal, and inputs the audio signal to the transmission-side signal processing unit 73. The transmission-side signal processing unit 73 generates a transmission signal by modulating the audio signal. The duplexer 72 inputs the transmission signal generated by the transmission-side signal processing unit 73 to the antenna 71.
The antenna 71 converts the transmission signal into radio waves, and outputs the radio waves. Also, the antenna 71 converts radio waves into a reception signal, which is an electrical signal, and inputs the reception signal to the duplexer 72. In the duplexer 72, the reception filter 78 allows a reception band portion of the reception signal to pass, and inputs the resulting reception signal to the reception-side signal processing unit 74. On the other hand, the transmission filter 77 does not allow the reception signal to pass since the passband thereof is different from the reception band. Accordingly, the reception signal is not input to the transmission-side signal processing unit 73. The reception-side signal processing unit 74 generates an audio signal by performing processing such as wave detection and amplification on the reception signal. The speaker 76 converts the audio signal into audio, and outputs the audio.
The transmission filter 77 and the reception filter 78 use a ladder filter 5 having the configuration illustrated in
Note that although the communication apparatus has been described as having a configuration including the microphone 75 and the speaker 76, there is no limitation to such configuration, and the communication apparatus may be an apparatus that does not necessarily need the microphone 75 or the speaker 76, or an apparatus that transmits and receives data other than audio data, such as a personal computer.
Although embodiments of the present invention have been described above, the present invention is not limited to the such specific embodiments, and various modifications and variations can be made within the scope of the gist of the present invention disclosed in the claims.
A filter of the present invention has a superior power durability, and is applicable to, for example, a duplexer in a communication apparatus.
Examples and conditional language recited herein are intended for pedagogical purposes to aid the reader in understanding the principles of the invention and the concepts contributed by the inventor to furthering the art, and are to be construed as being without limitation to such specifically recited examples and conditions, nor does the organization of such examples in the specification relate to a showing of the superiority and inferiority of the invention. Although the embodiment of the present invention has been described in detail, it should be understood that the various changes, substitutions, and alterations could be made hereto without departing from the spirit and scope of the invention.
Inoue, Kazunori, Matsuda, Takashi, Miura, Michio
Patent | Priority | Assignee | Title |
Patent | Priority | Assignee | Title |
5400950, | Feb 22 1994 | Delphi Technologies, Inc | Method for controlling solder bump height for flip chip integrated circuit devices |
5773917, | Oct 27 1993 | TAIYO YUDEN CO , LTD | Surface acoustic wave device and production process thereof |
5774962, | Oct 27 1993 | TAIYO YUDEN CO , LTD | Process for producing a surface acoustic wave device |
6310422, | Mar 12 1998 | SKYWORKS FILTER SOLUTIONS JAPAN CO , LTD | Surface acoustic wave filter |
7135944, | Dec 21 2001 | TAIYO YUDEN CO , LTD ; TAIYO YUDEN MOBILE TECHNOLOGY CO , LTD | Branching filter having both saw ladder and dual mode filters, and electronic apparatus using the branching filter |
20040029356, | |||
20040100342, | |||
20040155730, | |||
20050110596, | |||
20060158281, | |||
20060249825, | |||
20090096551, | |||
EP603928, | |||
EP1465337, | |||
JP2000196407, | |||
JP2003249842, | |||
JP2003332884, | |||
JP2006157174, | |||
JP2007116628, | |||
JP2007184690, | |||
JP7122961, | |||
RE38002, | Oct 27 1993 | TAIYO YUDEN CO , LTD | Process for providing a surface acoustic wave device |
RE38278, | Oct 27 1993 | TAIYO YUDEN CO , LTD | Surface acoustic wave device and production process thereof |
WO7114390, | |||
WO9852279, | |||
WO3000337, | |||
WO2007114390, |
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