Acoustic device packaging structure

Abstract

The present invention proposes an acoustic device packaging structure, including a circuit substrate having a first surface and a second surface relative to each other; an acoustic device, a gap is formed between the acoustic device and the first surface of the circuit substrate, and the acoustic device has an IDT electrode on the surface facing the first surface of the circuit substrate; a bump, and the acoustic device is arranged on the first surface of the circuit substrate through the bump; a connecting electrode, and the bump is electrically coupled to the acoustic device through the connecting electrode; and the connecting electrode is provided with a groove on the side facing the bump, and the groove is used to match the outer edge shape of the bump. The acoustic device packaging structure of the present invention can realize the slimming and miniaturization of the acoustic device on the basis of realizing the electrical filtering characteristics, and can reduce signal loss by shortening the connection distance between chips, thereby significantly improving the reliability of the acoustic device.

Description

Technical Field

[0001] The present invention relates to the field of surface acoustic wave technology, and in particular to a surface acoustic wave filter packaging method and packaging structure. Background Art

[0002] Currently, in communication devices such as mobile phones, filter devices are used to separate the transmit signal from another signal with a different frequency band, such as the receive signal. As more communication bands are used nationally or globally, and the requirements for filter performance continue to "tighten", the need for improved out-of-band filters and efforts for steeper skirts are relentless. The current state-of-the-art RF filter technology is based on microwave electroacoustic technology due to its small size and low manufacturing cost while providing excellent performance.

[0003] The dominant RF filter technology today is surface acoustic wave (SAW) technology, due to its robustness, design flexibility and low cost. However, the increasingly smaller terminal equipment requires the size of the acoustic device to meet the small size requirement. How to provide a new packaging method and packaging structure that can make the chip size close to that of wafer-level packaging, but the cost is much lower than that of wafer-level packaging; or the volume is smaller than that of the chip obtained by film packaging, but the cost is relatively close, has become an urgent problem to be solved. Summary of the invention

[0004] In order to solve the related problems in the prior art, the present invention provides an acoustic device packaging structure, including a circuit substrate having a first surface and a second surface relative to each other; an acoustic device, forming a gap between the acoustic device and the first surface of the circuit substrate, and the acoustic device has an IDT electrode on the surface facing the first surface of the circuit substrate; a bump, and the acoustic device is arranged on the first surface of the circuit substrate through the bump; a connecting electrode, and the bump is electrically coupled to the acoustic device through the connecting electrode; the connecting electrode is provided with a groove on the side facing the bump, and the groove is used to match the shape of the outer edge of the bump.

[0005] Furthermore, the connecting electrode is a single layer and is electrically coupled with the IDT electrode inside the acoustic device.

[0006] Wherein, the groove has a square cross-section.

[0007] Wherein, the groove has a circular cross-section.

[0008] The bottom of the cross section of the groove is no more than 2 um away from the acoustic device.

[0009] Furthermore, the connecting electrode is a double layer, including a pad layer and an IDT electrode layer, the pad layer is arranged on a side close to the bump, and the IDT electrode layer is arranged on a side away from the bump.

[0010] Wherein, the groove is arranged on a side of the liner layer facing the bump.

[0011] Wherein, the groove has a square cross-section.

[0012] Wherein, the groove has a circular cross-section.

[0013] The bottom of the groove cross section is no more than 2 um away from the IDT electrode layer.

[0014] The bottom of the groove cross section extends to the IDT electrode layer.

[0015] Furthermore, the groove is arranged on a side of the IDT electrode layer facing the liner layer, so as to match the shape of an outer edge of the liner layer.

[0016] The bottom of the groove cross section is no more than 2 um away from the acoustic device.

[0017] Wherein, the bottom of the groove cross section extends to the acoustic device.

[0018] Furthermore, the present invention also provides a method for manufacturing an acoustic device packaging structure, comprising: providing a piezoelectric substrate having an upper surface and a lower surface arranged opposite to each other, forming an IDT electrode on the upper surface of the piezoelectric substrate, wherein the IDT electrode is a comb-tooth electrode with uniform thickness; forming a connecting electrode on the upper surface of the piezoelectric substrate, wherein a groove is formed on the side of the connecting electrode facing the bump; connecting the bump to the groove so that the groove matches the shape of the outer edge of the bump; providing a circuit substrate having a first surface and a second surface relative to each other; arranging the upper surface of the piezoelectric substrate relative to the first surface of the circuit substrate, and mounting them to form the acoustic device packaging structure.

[0019] According to the acoustic device packaging structure of the present invention, the acoustic device can be further slimmed down and miniaturized on the basis of achieving electrical filtering characteristics, and signal loss can be reduced by shortening the connection distance between chips, thereby significantly improving the reliability of the acoustic device and enhancing the working stability of the acoustic device. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] The accompanying drawings are used to provide a further understanding of the present invention and constitute a part of the specification. Together with the following specific embodiments, they are used to explain the present invention but do not constitute a limitation of the present invention. In the accompanying drawings:

[0021] Figure 1 4 is a schematic cross-sectional view of the packaging structure of an acoustic device according to the first embodiment of the present invention.

[0022] Figure 2 1 is an enlarged cross-sectional schematic diagram of the connection electrode of the acoustic device packaging structure according to the first embodiment of the present invention.

[0023] Figure 3 4 is a cross-sectional schematic diagram of the packaging structure of the acoustic device according to the second embodiment of the present invention.

[0024] Figure 4 1 is a schematic cross-sectional view of an enlarged connecting electrode of the acoustic device packaging structure according to the second embodiment of the present invention.

[0025] Figure 5 Schematic diagram of the connection electrode structure of the acoustic device packaging structure according to the second embodiment of the present invention.

[0026] Figure 6 1 is an enlarged cross-sectional schematic diagram of the connection electrode of the acoustic device packaging structure according to the third embodiment of the present invention.

[0027] Figure 7 Schematic diagram of the connection electrode structure of the acoustic device module packaging structure according to the third embodiment of the present invention.

[0028] Figure 8 4 is a flow chart of a preparation process of an acoustic device package according to an embodiment of the present invention.

[0029] Reference numerals:

[0030] 1. Circuit board

[0031] 11-First surface

[0032] 12- Second surface

[0033] 2.20-Acoustic Device

[0034] 3.30-bump

[0035] 4, 40, 400 - Connecting electrodes

[0036] 41, 401- cushion layer

[0037] 42, 402-IDT electrode layer

[0038] 5, 50, 500-groove

[0039] 6-IDT electrode DETAILED DESCRIPTION

[0040] In order to more clearly understand the above-mentioned purpose, features and advantages of the present invention, the present invention is further described in detail below in conjunction with the accompanying drawings and specific embodiments. It should be noted that the embodiments of the present application and the features in the embodiments can be combined with each other without conflict.

[0041] In the following description, many specific details are set forth to facilitate a full understanding of the present invention. However, the present invention may also be implemented in other ways different from those described herein. Therefore, the protection scope of the present invention is not limited to the specific embodiments disclosed below.

[0042] Embodiment 1

[0043] like Figure 1 As shown, the present embodiment provides an acoustic device packaging structure, including a circuit substrate 1 having a first surface 11 and a second surface 12 relative to each other; an acoustic device 2, forming a gap with the first surface 11 of the circuit substrate 1, and the acoustic device 2 having an IDT electrode on the surface facing the first surface 11 of the circuit substrate 1; a bump 3, and the acoustic device is arranged on the first surface 11 of the circuit substrate 1 through the bump 3; and a connecting electrode 4, and the bump 3 is electrically coupled to the acoustic device through the connecting electrode 4. The bump of the present invention is usually made of a metal with good conductive properties, such as gold, tin, etc., so that a good electrical connection is formed between the circuit substrate and the acoustic device 2. In addition to the electrical connection function, the bump also has a heat dissipation function. Figure 1 In the acoustic device packaging structure shown, for the sake of clarity, the shape of the bump is spherical, and in the actual structure, the bump shape can also be designed to be a cylindrical, prism or other shape that is easy to process and realize, and the number of the bumps can be set to 4 or 6. However, the present invention is not limited thereto.

[0044] The acoustic device is packaged in this flip chip packaging method, and the side with the IDT electrode is set in the gap formed between the acoustic device and the first surface of the circuit substrate, so as to avoid the sealing material such as resin or the substrate surface from contacting the IDT electrode, thereby avoiding affecting the sensitive IDT electrode. Among them, the acoustic device can be SAW, XBAR, etc., and the circuit substrate is a commonly used circuit board such as PCB or other forms of multi-layer wiring circuit boards, but the present invention is not limited thereto.

[0045] The connecting electrode 4 is provided with a groove 5 on the side facing the bump, and the groove 5 is used to match the shape of the outer edge of the bump. Through this completely fitting shape matching, not only can a more effective connection between the bump and the acoustic device be achieved, but also the packaging size of the acoustic device can be further slimmed down and miniaturized, thereby reducing the installation volume.

[0046] In this embodiment, Figure 2As shown, the connecting electrode 4 is a single-layer structure, which can be a pad or an interface of an IDT electrode. The connecting electrode 4 is electrically coupled to the IDT electrode 6 inside the acoustic device 2. From the specific process implementation, the cross section of the groove can be any shape, such as a circular cross section, such as Figure 2 (a). Or a cross section with a corner shape other than a circular cross section, such as a square cross section, a rectangular cross section, a trapezoidal cross section, an inverted trapezoidal cross section, etc. In the present invention, these cross sections with corner shapes are collectively referred to as square cross sections, such as Figure 2 (b). In the specific process implementation, the bottom of the cross section of the groove is no more than 2um away from the acoustic device 2. Preferably, it is less than and close to the range of 2um, so that the package size can be further thinned and miniaturized on the basis of ensuring sufficient electrical connection between the bump and the acoustic device 2 to achieve the filtering effect.

[0047] Embodiment 2

[0048] like Figure 3 The figure shows a cross-sectional schematic diagram of the acoustic device packaging structure of the second embodiment. Similar to the first embodiment, it includes a circuit substrate, an acoustic device 20, a gap is formed between the acoustic device 20 and the first surface of the circuit substrate, and the acoustic device 20 has an IDT electrode on the surface facing the first surface of the circuit substrate; a bump 30, and the acoustic device 20 is arranged on the first surface of the circuit substrate through the bump 30; and a connecting electrode 40, and the bump 30 is electrically coupled to the acoustic device 20 through the connecting electrode 40. The connecting electrode 40 is provided with a groove 50 on the side facing the bump, and the groove 50 is used to match the shape of the outer edge of the bump. Through this completely fitting shape matching, not only can a more effective connection between the bump and the acoustic device be achieved, but also the slimming and miniaturization of the acoustic device packaging size can be further achieved, thereby reducing the installation volume.

[0049] The difference from the first embodiment is that the connection electrode 40 of the acoustic device packaging structure of the second embodiment is a double-layer structure, including a liner layer 41 and an IDT electrode layer 42, the liner layer 41 is arranged on a side close to the bump 30, and the IDT electrode layer 42 is arranged on a side away from the bump 30, such as Figure 4 and Figure 5 The connecting electrode 40 is electrically coupled to the IDT electrode inside the acoustic device 20. The groove 50 is provided on the side of the liner layer 41 facing the bump, and is used to match the outer edge shape of the bump. In terms of specific process implementation, the cross section of the groove 50 can be any shape, for example, a circular cross section, such as Figure 4Or it may be a cross section with a corner shape other than a circular cross section, such as a square cross section, a rectangular cross section, a trapezoidal cross section, an inverted trapezoidal cross section, etc. In the present invention, these cross sections with corner shapes are collectively referred to as square cross sections, such as Figure 4 (a) shows an inverted trapezoidal cross section. In the specific process implementation, the bottom of the cross section of the groove is no more than 2um away from the IDT electrode layer 42. Preferably, it is less than or close to 2um, so that the package size can be further thinned and miniaturized on the basis of ensuring sufficient electrical connection between the bump and the acoustic device to achieve filtering effect.

[0050] In this embodiment, further improved design can be made to extend the bottom of the cross section of the groove 50 to the IDT electrode layer 42, so as to further achieve slimming and miniaturization of the package size without sacrificing electrical properties.

[0051] Embodiment 3

[0052] like Figure 6 The figure is a cross-sectional schematic diagram of the acoustic device packaging structure of the third embodiment. Similar to the second embodiment, it includes a circuit substrate, an acoustic device 200, a gap is formed between the acoustic device 200 and the first surface of the circuit substrate, and the acoustic device 200 has an IDT electrode on the surface facing the first surface of the circuit substrate; a bump, and the acoustic device 200 is arranged on the first surface of the circuit substrate through the bump; and a connecting electrode 400, and the bump is electrically coupled to the acoustic device 200 through the connecting electrode 400. Similarly, the connecting electrode 400 of the acoustic device packaging structure is a double-layer structure, including a pad layer 401 and an IDT electrode layer 402, and the pad layer 401 is arranged on a side close to the bump, and the IDT electrode layer 402 is arranged on a side away from the bump, as shown in FIG. Figure 6 and Figure 7 The connecting electrode 400 is electrically coupled to the IDT electrode inside the acoustic device.

[0053] The difference between this embodiment and the second embodiment is that the groove 500 is arranged on the side of the IDT electrode layer 402 facing the liner layer 401, and is used to match the outer edge shape of the liner layer 401, and then match the outer edge shape of the bump by matching the outer edge shape of the liner layer 401, such as Figure 6 From the specific process implementation, the cross section of the groove 500 can be any shape, for example, a circular cross section, such as Figure 6 As shown in (c), further improved design can be made by extending the bottom of the groove 500 cross section to the acoustic device 200, such as Figure 6Or it may be a cross section with a corner shape other than a circular cross section, such as a square cross section, a rectangular cross section, a trapezoidal cross section, an inverted trapezoidal cross section, etc. In the present invention, these cross sections with corner shapes are collectively referred to as square cross sections, such as Figure 6 (a) shows a rectangular cross section. In a specific process implementation, the bottom of the cross section of the groove is no more than 2 um away from the acoustic device.

[0054] In this embodiment, further improved design can be made to extend the bottom of the cross section of the groove 500 to the surface of the acoustic device 200, such as Figure 6 As shown in (b), the package size can be further reduced in thickness and miniaturization while ensuring sufficient electrical connection between the bump and the acoustic device to achieve a filtering effect.

[0055] Embodiment 4 provides an exemplary technical solution related to the manufacturing process of the acoustic device packaging structure:

[0056] Embodiment 4

[0057] like Figure 8 As shown, the present invention also provides a method for manufacturing the acoustic device packaging structure as described in claim 1, comprising the following steps: providing a piezoelectric substrate having an upper surface and a lower surface (a1) arranged oppositely, forming an IDT electrode on the upper surface of the piezoelectric substrate, wherein the IDT electrode is a comb-tooth electrode with uniform thickness (a2); forming a connecting electrode on the upper surface of the piezoelectric substrate, wherein a groove is formed on the side of the connecting electrode facing the bump (a3); connecting the bump to the groove, so that the groove matches the outer edge shape of the bump (a4); providing a circuit substrate having a first surface and a second surface relative to each other (a5); arranging the upper surface of the piezoelectric substrate oppositely to the first surface of the circuit substrate, and mounting them, thereby forming a hollow packaging structure enclosed by the piezoelectric substrate and the acoustic device (a6). The connection between the bump and the groove can be made by ultrasonic connection or by soldering by heating in a tin furnace.

[0058] According to the acoustic device packaging structure of this embodiment, the acoustic device can be made thinner and smaller on the basis of achieving electrical filtering characteristics, and signal loss can be reduced by shortening the connection distance between chips, thereby significantly improving the reliability of the acoustic device.

[0059] In the present invention, the terms "first" and "second" are used for descriptive purposes only and cannot be understood as indicating or implying relative importance; the term "plurality" means two or more. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0060] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. An acoustic device packaging structure, comprising a circuit substrate having a first surface and a second surface opposite to each other; an acoustic device, forming a gap with the first surface of the circuit substrate, the acoustic device having an IDT electrode on a surface facing the first surface of the circuit substrate; a bump, wherein the acoustic device is disposed on the first surface of the circuit substrate through the bump; A connecting electrode, wherein the bump is electrically coupled to the acoustic device through the connecting electrode; characterized in that: The connecting electrode is provided with a groove on a side facing the bump, and the groove is used to match the shape of the outer edge of the bump; The connecting electrode is a double layer, including a pad layer and an IDT electrode layer, wherein the pad layer is arranged on a side close to the bump, and the IDT electrode layer is arranged on a side away from the bump; The groove is arranged on a side of the IDT electrode layer facing the liner layer, and is used to match the shape of the outer edge of the liner layer.

2. The acoustic device packaging structure according to claim 1, characterized in that: The groove is disposed on a side of the liner layer facing the bump.

3. The acoustic device packaging structure according to claim 2, characterized in that: The groove has a square cross-section.

4. The acoustic device packaging structure according to claim 2, characterized in that: The groove has a circular cross-section.

5. The acoustic device packaging structure according to claim 2, characterized in that: The bottom of the groove cross section is no more than 2 um away from the IDT electrode layer.

6. The acoustic device packaging structure according to claim 2, characterized in that: The bottom of the groove cross section extends to the IDT electrode layer.

7. The acoustic device packaging structure according to claim 1, characterized in that: The bottom of the groove cross section is no more than 2 um away from the acoustic device.

8. The acoustic device packaging structure according to claim 1, characterized in that: The bottom of the groove cross section extends to the acoustic device.

9. A method for manufacturing the acoustic device packaging structure according to claim 1, comprising: Providing a piezoelectric substrate having an upper surface and a lower surface arranged opposite to each other, forming an IDT electrode on the upper surface of the piezoelectric substrate, wherein the IDT electrode is a comb-tooth electrode with uniform thickness; A connecting electrode is formed on the upper surface of the piezoelectric substrate, and a groove is formed on a side of the connecting electrode facing the bump; Connecting the protrusion into the groove so that the groove matches the outer edge of the protrusion; Providing a circuit substrate having a first surface and a second surface opposite to each other; The upper surface of the piezoelectric substrate is arranged opposite to the first surface of the circuit substrate, and mounted to form the acoustic device packaging structure.

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