Elastic wave device and communication apparatus

Abstract

The present application relates to an elastic wave device and a communication device, the elastic wave device comprising: a package substrate; a piezoelectric substrate configured opposite to the package substrate and connected by a plurality of bumps; the bumps include a first bump also used for heat dissipation; a plurality of series resonators formed on the piezoelectric substrate, each series resonator is connected in series by a corresponding wiring; a cross-coupled capacitor formed on the piezoelectric substrate, a first end of the cross-coupled capacitor is connected to a first wiring between two series resonators, and a second end of the cross-coupled capacitor is connected to a first bump pad of the first bump joint. By utilizing the first bump used for heat dissipation as a path for the cross-coupled capacitor to the package substrate, the wiring can be effectively reduced, and the occupied area can be reduced.

Description

Technical Field

[0001] This application relates to the field of signal filtering technology, and in particular to an elastic wave device and a communication device. Background Technology

[0002] With the development of technology and the continuous progress of society, the requirements for signal accuracy of communication equipment are becoming increasingly stringent. Many communication devices have adopted elastic wave devices for signal filtering. In traditional elastic wave devices, the wiring inside the chip usually intersects with signal lines and occupies a large area, which has the disadvantage of large footprint. Summary of the Invention

[0003] Therefore, it is necessary to provide an elastic wave device and communication device that can reduce the area occupied, in order to address the above problems.

[0004] The first aspect of this application provides an elastic wave device, comprising: Packaging substrate; A piezoelectric substrate is disposed opposite to the encapsulation substrate and engaged by a plurality of bumps; the bumps include a first bump that also serves for heat dissipation. Multiple series resonators formed on the piezoelectric substrate are connected in series sequentially through corresponding wiring connections. A cross-coupled capacitor is formed on the piezoelectric substrate, the first end of which is connected to a first wiring between the two series resonators, and the second end of which is connected to a first bump pad of the first bump joint.

[0005] In one embodiment, the elastic wave device further includes: Multiple parallel resonators formed on the piezoelectric substrate, the bumps further include a second bump for engagement, and the packaging substrate includes a second wiring for electrically connecting the first bump and the second bump; The first end of the parallel resonator is connected between the corresponding series resonators and is a wiring different from the first wiring. The second end of the parallel resonator is connected to the second bump pad of the second bump engagement.

[0006] In one embodiment, the first ends of at least two parallel resonators are respectively connected to wiring between corresponding series resonators, which is different from the first wiring, and the second ends are jointly connected to the second bump pad of the second bump engagement.

[0007] In one embodiment, the first end of at least one parallel resonator is connected in parallel to the wiring to which the corresponding series resonator is connected, and the second end is separately connected to the bump pad of the corresponding bump engagement.

[0008] In one embodiment, the first bump pad of the first bump engagement is formed on the piezoelectric substrate at a location closer to the central region than the bump pads of other bump engagements.

[0009] In one embodiment, the packaging substrate further includes a planar ground pattern and a first inductor, wherein wiring between the first bump and the second bump is connected to the planar ground pattern via the first inductor.

[0010] In one embodiment, the inductance value of the first inductor is greater than or equal to 0.05nH and less than or equal to 0.25nH.

[0011] In one embodiment, the packaging substrate further includes a second inductor connected in series with wiring between the first bump and the second bump.

[0012] In one embodiment, the capacitance value of the cross-coupled capacitor is greater than or equal to 0.05pF and less than or equal to 0.25pF.

[0013] A second aspect of this application provides a communication device, including an antenna and the aforementioned elastic wave device.

[0014] In the aforementioned elastic wave device and communication apparatus, the piezoelectric substrate and the packaging substrate are arranged opposite each other in the elastic wave device and are joined by multiple bumps. The first end of a cross-coupling capacitor in the piezoelectric substrate is connected to a first wiring between two series resonators, and the second end of the cross-coupling capacitor is connected to a first bump pad joined by the first bump. By utilizing the first bump, which serves as a heat dissipation surface, as a path for the cross-coupling capacitor to lead to the packaging substrate, wiring can be effectively reduced, and the occupied area can be decreased. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of the structure of an elastic wave device in one embodiment; Figure 2 This is a schematic diagram showing the distribution of cross-coupling capacitors and bump pads in one embodiment; Figure 3 This is a schematic diagram of the structure of an elastic wave device in one embodiment; Figure 4 This is a thermal simulation data diagram of an elastic wave device without heat sink bumps. Figure 5 for Figure 3 Thermal simulation data of a medium elastic wave device; Figure 6 for Figure 3 Schematic diagram of optimized filtering characteristics of elastic wave devices; Figure 7 This is a schematic diagram of the structure of the elastic wave device in another embodiment; Figure 8 for Figure 7 A schematic diagram of the filtering characteristics of a medium elastic wave device.

[0016] Reference numerals: 100, packaging substrate; 101, wiring; 200, piezoelectric substrate; 201, first wiring; 202, second wiring; 203, third wiring; 204, fourth wiring; 205, fifth wiring; 300, bump; 400, bump pad; 401, first bump pad; 402, second bump pad; 403, third bump pad; 404, fourth bump pad. Detailed Implementation

[0017] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application.

[0018] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the application.

[0019] It is understood that the terms "first," "second," etc., used in this application may be used to describe various elements, but these elements are not limited by these terms. These terms are only used to distinguish one element from another. In the following embodiments, "connection" should be understood as "electrical connection," "communication connection," etc., if the connected circuits, modules, units, etc., have the transmission of electrical signals or data between them.

[0020] When used herein, the singular forms of “a,” “an,” and “the” may also include the plural forms unless the context clearly indicates otherwise. It should also be understood that the terms “comprising,” “including,” or “having,” etc., specify the presence of the stated feature, whole, operation, component, part, or combination thereof, but do not preclude the possibility of the presence or addition of one or more other features, wholes, operations, components, parts, or combinations thereof.

[0021] In one embodiment, such as Figure 1As shown, an elastic wave device is provided, including a packaging substrate 100 and a piezoelectric substrate 200. The piezoelectric substrate 200 is configured opposite to the packaging substrate 100 and is connected by a plurality of bumps 300. The number of bumps 300 is not unique, and may include, for example, a first bump, a second bump, a third bump, etc. The specific number can be set according to the area of ​​the piezoelectric substrate 200 and the number of devices. The bumps 300 may be formed on the packaging substrate 100. The piezoelectric substrate 200 is provided with bump pads 400 corresponding to each bump 300. The bumps 300 are directly or indirectly connected to the planar ground pattern GND on the packaging substrate 100. The materials of the bumps 300 and the bump pads 400 are not unique, and may be materials such as gold or solder, so that the piezoelectric substrate 200 and the packaging substrate 100 can be joined to achieve electrical connection. The packaging substrate 100 is also provided with wiring to connect different bumps 300, or to directly connect some bumps 300 to the planar ground pattern GND.

[0022] The elastic wave device also includes a cross-coupling capacitor (CCC) formed on the piezoelectric substrate 200 and multiple series resonators. The bump 300 includes a first bump for heat dissipation. Each series resonator is connected in series via corresponding wiring connections. The first end of the cross-coupling capacitor is connected to the first wiring between two series resonators, and the second end of the cross-coupling capacitor is connected to the first bump pad where the first bump engages. Specifically, the bump 300 can be made of a conductive material with good thermal conductivity, such as... Figure 2 As shown, the first bump pad 401, which is engaged with the first bump, is formed on the piezoelectric substrate 200 at a position closer to the central region than the bump pads engaged with other bumps (bumps different from the first bump, such as the second bump, the third bump, etc.). The central region refers to the area formed at a certain distance around the geometric center of the piezoelectric substrate 200, which can be circular, rectangular, or other shaped areas. The specific position of the first bump pad 401 is not unique; it only needs to be closer to the central region than the bump pads engaged with other bumps to facilitate better heat dissipation. The cross-coupling capacitor C can be arranged inside or outside the chip. In this embodiment, the cross-coupling capacitor C is arranged inside the chip, specifically close to the first bump pad 401, for convenient electrical connection. The cross-coupling capacitor C can help achieve specific frequency responses, such as bandpass, bandstop, or all-pass characteristics, thereby playing a role in selectively passing or suppressing specific frequency signals in the filter. In this embodiment, the bump used to connect from the cross-coupling capacitor C to the chip's external ground pattern is shared with the heat dissipation bump arranged near the center of the chip. This eliminates the need for additional wiring inside the chip, thus enabling a reduction in chip size and area footprint.

[0023] Furthermore, the elastic wave device also includes a plurality of parallel resonators formed on the piezoelectric substrate 200, and the bumps also include second bumps for bonding. The package substrate 100 includes second wiring for electrically connecting the first bump and the second bump. The first end of the parallel resonator is connected to a wiring different from the first wiring between corresponding series resonators, and the second end of the parallel resonator is connected to a second bump pad for bonding with the second bump.

[0024] Specifically, multiple series resonators and multiple parallel resonators constitute a ladder filter. The ladder filter can be connected between the antenna terminal Ant and the transmitting terminal Tx, or between the antenna terminal Ant and the receiving terminal Rx. The number of series and parallel resonators is not unique and can be set according to actual needs. The series resonators are connected in series sequentially, and the first end of each parallel resonator is connected in parallel to the wiring between the corresponding series resonators (or between the series resonator and the terminal). The second end of each parallel resonator is connected to the bump pad of the corresponding bump 300 engagement. For example... Figure 3 As shown (bump 300 not shown), taking the trapezoidal filter connected between the antenna terminal Ant and the transmitting terminal Tx as an example, the series resonator includes series resonators S1, S2, S3, and S4 connected in series via wiring. Series resonator S1 is connected to the antenna terminal Ant via wiring, and series resonator S4 is connected to the transmitting terminal Tx via wiring. The wiring between series resonators S3 and S4 serves as the first wiring 201. The first end of the cross-coupling capacitor C is connected to the first wiring 201 between series resonators S3 and S4, and the second end of the cross-coupling capacitor C is connected to the first bump pad 401 of the first bump joint. The capacitance value of the cross-coupling capacitor C is not unique; it can be greater than or equal to 0.05 pF (picofarad) and less than or equal to 0.25 pF, for example, 0.05 pF, 0.1 pF, 0.15 pF, 0.2 pF, 0.25 pF, etc. In this embodiment, the capacitance value of the cross-coupling capacitor C is 0.1 pF.

[0025] In one embodiment, the first ends of at least two parallel resonators are respectively connected to wiring between corresponding series resonators, which is different from the first wiring, and the second ends are jointly connected to the second bump pad of the second bump engagement. In addition, the first end of at least one parallel resonator is connected in parallel to the wiring to which the corresponding series resonator is connected, and the second end is separately connected to the bump pad of the corresponding bump engagement (a bump different from the first bump and the second bump).

[0026] Continue to refer to Figure 3The parallel resonators include parallel resonators P1, P2, P3, and P4. The first end of parallel resonator P1 is connected to the third wiring 203 between series resonators S1 and S2. The first end of parallel resonator P2 is connected to the fourth wiring 204 between series resonators S2 and S3. The second ends of parallel resonators P1 and P2 are connected via a second wiring 202, which is connected to a second bump pad 402 of a second bump engagement. Wiring 101 is provided in the package substrate 100 to electrically connect the first bump and the second bump. The first end of parallel resonator P3 is connected to the first wiring 201 between series resonators S3 and S4, and the second end is connected to the third bump pad 403 of the third bump engagement. The first end of parallel resonator P4 is connected to the fifth wiring 205 between series resonator S4 and the emitter terminal Tx, and the second end is connected to the fourth bump pad 404 of the fourth bump engagement.

[0027] In one embodiment, such as Figure 3 As shown, the packaging substrate 100 also includes a planar ground pattern GND and a first inductor L1. The wiring 101 between the first bump and the second bump is connected to the planar ground pattern GND through the first inductor L1. Correspondingly, the third bump and the fourth bump are directly connected to the planar ground pattern GND through wiring on the packaging substrate 100. The first inductor L1 can be formed inside or outside the chip, and the inductance value of the first inductor L1 is not unique. It can be greater than or equal to 0.05nH (nanohenries) and less than or equal to 0.25nH, for example, 0.05nH, 0.1nH, 0.15nH, 0.2nH, 0.25nH, etc. The specific value can be set according to actual needs. In this embodiment, the inductance value of the first inductor L1 is 0.1nH.

[0028] In existing elastic wave devices, the bumps used for heat dissipation are either connected to the resonator in the piezoelectric substrate 200 or to the ground line in the package substrate 100, serving only as chip heat dissipation. Internal chip wiring typically intersects with signal lines and occupies a large area. In this application, the cross-coupling capacitor C in the piezoelectric substrate 200 is connected to the first bump pad 401 used for heat dissipation. On the package substrate 100, the wiring 101 between the first and second bumps is connected to the planar ground pattern GND through the first inductor L1. The first bump is not connected to the resonator on the chip side, nor to the planar ground pattern GND on the package side. That is, both sides of the first bump are signal lines, and it can also function as a heat dissipation bump. By effectively utilizing the first bump, located near the center of the chip for heat dissipation, as a signal path, excellent heat dissipation performance is achieved, and the attenuation pole can be shifted. Figure 4The image shows thermal simulation data for an elastic wave device without heat dissipation bumps. A large amount of heat is easily generated at the transmitting end of the communication device, mainly concentrated at the resonator location, with the highest temperature reaching 88.4℃. Figure 5 As shown Figure 3 The thermal simulation data of the elastic wave device shows that utilizing the first bump as a signal path also provides excellent heat dissipation performance, reducing the highest temperature at the resonator location to 86.6℃. The circuit containing the first inductor L1 serves as the main signal path; the larger the linewidth, the shorter the length, and the higher the Q value of the first inductor L1, the better its passband performance. Figure 6 As shown Figure 3 A schematic diagram illustrating the optimized filtering characteristics of a medium-elastic wave device. Figure 3 The elastic wave device in the middle can shift the attenuation pole to a lower frequency compared to existing technologies, that is, the attached elastic wave device. Figure 6 The red curve (existing technology attenuation pole) moves along the arrow direction to a lower frequency. In the figure, red represents the filtering characteristic curve of the existing technology, and blue represents... Figure 3 The filtering characteristic curve of the elastic wave device is shown, with the horizontal axis representing frequency (GHz) and the vertical axis representing attenuation. It is clear that the attenuation peak of the existing technology is 4.6 GHz. Figure 3 The attenuation pole of the elastic wave device is 4.05 GHz, which is 0.55 GHz lower than the existing technology, thus achieving the shift of the attenuation pole to a lower frequency.

[0029] In addition, such as Figure 7 As shown, the packaging substrate 100 also includes a second inductor L2, which is connected in series with the wiring 101 between the first bump and the second bump. The inductance value of the second inductor L2 is not unique; it can be greater than or equal to 0.5nH and less than or equal to 2.5nH, such as 0.5nH, 1nH, 1.5nH, 2nH, 2.5nH, etc. In this embodiment, the inductance value of the second inductor L2 is 1nH. By adding a coil to the packaging substrate 100 to form the second inductor L2, there is no significant impact on the overall waveform (even if designed to be thinner and longer, there is no problem), thus providing greater design freedom. Figure 8 As shown Figure 7 The schematic diagram of the filtering characteristics of the elastic wave device also shows a low-frequency attenuation pole.

[0030] In one embodiment, a communication device is also provided, including an antenna and the aforementioned elastic wave device, wherein the antenna is connected to an antenna terminal in the elastic wave device. The communication device includes a transmitting filter and a receiving filter, wherein the transmitting filter and / or the receiving filter employs the aforementioned elastic wave device, and both the transmitting filter and the receiving filter are connected to the antenna via antenna terminals.

[0031] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0032] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this patent application should be determined by the appended claims.

Claims

1. An elastic wave device, characterized in that, include: Packaging substrate; A piezoelectric substrate is disposed opposite to the encapsulation substrate and engaged by a plurality of bumps; the bumps include a first bump that is also used for heat dissipation. Multiple series resonators formed on the piezoelectric substrate are connected in series sequentially through corresponding wiring connections. A cross-coupled capacitor is formed on the piezoelectric substrate, the first end of which is connected to a first wiring between the two series resonators, and the second end of which is connected to a first bump pad of the first bump joint.

2. The elastic wave device according to claim 1, characterized in that, Also includes: Multiple parallel resonators formed on the piezoelectric substrate, the bumps further include a second bump for engagement, and the packaging substrate includes a second wiring for electrically connecting the first bump and the second bump; The first end of the parallel resonator is connected between the corresponding series resonators, and is a wiring different from the first wiring. The second end of the parallel resonator is connected to the second bump pad of the second bump engagement.

3. The elastic wave device according to claim 2, characterized in that, The first ends of at least two parallel resonators are respectively connected to the corresponding series resonators via wiring different from the first wiring, and the second ends are connected together to the second bump pad of the second bump joint.

4. The elastic wave device according to claim 2, characterized in that, At least one parallel resonator has its first end connected in parallel to the wiring connected to the corresponding series resonator, and its second end is separately connected to the bump pad of the corresponding bump engagement.

5. The elastic wave device according to claim 2, characterized in that, The first bump pad of the first bump engagement is formed on the piezoelectric substrate at a position closer to the central region than the bump pads of other bump engagements.

6. The elastic wave device according to claim 2, characterized in that, The packaging substrate further includes a planar ground pattern and a first inductor, and the wiring between the first bump and the second bump is connected to the planar ground pattern through the first inductor.

7. The elastic wave device according to claim 6, characterized in that, The inductance value of the first inductor is greater than or equal to 0.05nH and less than or equal to 0.25nH.

8. The elastic wave device according to claim 6, characterized in that, The packaging substrate further includes a second inductor, which is connected in series with the wiring between the first bump and the second bump.

9. The elastic wave device according to any one of claims 1 to 8, characterized in that, The capacitance value of the cross-coupling capacitor is greater than or equal to 0.05pF and less than or equal to 0.25pF.

10. A communication device, characterized in that, It includes an antenna and the elastic wave device according to any one of claims 1 to 9.

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