Elastic wave device and module

Abstract

The utility model relates to an elastic wave device and a module thereof, the elastic wave device comprises a device chip, a packaging substrate and a supporting layer, one surface of the packaging substrate is jointed with one surface of the supporting layer, and the packaging substrate is used for being connected with an external circuit; the other surface of the supporting layer is jointed with the main surface of the device chip; the supporting layer is provided with conductive through holes; conductive metal is arranged in the conductive through hole; wherein one surface of the packaging substrate is provided with a bump bonding pad, and the bump bonding pad is jointed with the conductive metal; the length of the bump pad is smaller than the aperture of the conductive through hole; the sum of the thickness of the bump pad and the thickness of the conductive metal is greater than the height of the conductive via in a direction perpendicular to the one surface of the support layer. According to the elastic wave device and the module thereof, the problems that the manufacturing cost of a traditional WLP packaging structure is high, and layering is prone to occurring at the joint of the roof layer and the supporting layer are solved, and the frequency stability and the quality factor of the elastic wave device are guaranteed while the manufacturing cost of the WLP packaging structure is reduced.

Description

Technical Field

[0001] This utility model relates to the field of semiconductor packaging technology, and in particular to an elastic wave device and module. Background Technology

[0002] Currently, wafer-level packaging (WLP) or chip-scale packaging (CSP) are commonly used in the packaging technology of elastic wave devices to meet their packaging requirements. WLP packaging is an advanced semiconductor packaging technology that, compared to traditional CSP packaging, can significantly reduce package size and allow multiple elastic wave devices to be processed simultaneously on the same wafer, thereby reducing manufacturing time and cost. Furthermore, WLP can improve electrical performance and shorten signal transmission paths, thus enhancing the overall performance of the elastic wave device.

[0003] Traditional WLP (Wave Plate Laying) packaging structures typically consist of a packaging substrate, a roof layer, a support layer, and a device chip. The roof layer, support layer, and device chip form a sealed internal space to ensure the frequency stability and quality factor of the elastic wave device and to prevent the molding compound from entering the internal space. However, this structure requires multiple photolithography processes, resulting in high manufacturing costs. Furthermore, since the roof layer and support layer are generally made of resin, delamination is prone to occur at the junction of the roof layer and support layer, potentially leading to poor sealing of the internal space.

[0004] The traditional WLP packaging structure has high manufacturing costs and is prone to delamination at the junction of the roof layer and the support layer, and there is currently no suitable solution. Utility Model Content

[0005] This embodiment provides an elastic wave device and module to solve the problems of high manufacturing cost of traditional WLP packaging structure and delamination at the junction of roof layer and support layer.

[0006] In a first aspect, this embodiment provides an elastic wave device, including a device chip, a packaging substrate, and a support layer, wherein the device chip has electrode pads, characterized in that:

[0007] One side of the packaging substrate is joined to one side of the support layer for connection with external circuitry;

[0008] The other side of the support layer is bonded to the main surface of the device chip; the support layer has conductive vias; the conductive vias have conductive metal and electrode pads, wherein the conductive metal is formed on the electrode pads;

[0009] One side of the packaging substrate has a bump pad, which is bonded to the conductive metal; the length of the bump pad is less than the diameter of the conductive via; in a direction perpendicular to the side of the support layer, the sum of the thicknesses of the bump pad, the conductive metal, and the electrode pad is greater than the height of the conductive via.

[0010] In some of these embodiments, the conductive metal includes metal bumps, columnar metal, and a seed layer;

[0011] The metal bump is formed above the columnar metal; the seed layer is formed at the bottom of the columnar metal and on the inner wall of the conductive via.

[0012] In some embodiments, the device chip further includes a piezoelectric substrate, an IDT electrode, and a wiring area;

[0013] The IDT electrode is formed on the main surface of the piezoelectric substrate;

[0014] The wiring area electrically connects the electrode pads and the IDT electrodes.

[0015] In some embodiments, the sum of the thicknesses of the conductive metal and the electrode pads is less than the height of the conductive via.

[0016] In some of these embodiments, the supporting layer is made of silicon oxide or silicon nitride.

[0017] In some embodiments, the metal bump is made of at least one of copper, nickel, and a tin-silver alloy.

[0018] In some embodiments, the height of the support layer is greater than the thickness of the electrode pads.

[0019] In some embodiments, one side of the packaging substrate is covered with silicon material covering one side of the electrode pads and the wiring area.

[0020] Secondly, this utility model provides a module comprising a plurality of elastic wave devices as described in the first aspect above.

[0021] Compared with related technologies, this embodiment provides an elastic wave device and module, including a device chip, a packaging substrate, and a support layer. The device chip has electrode pads, and one side of the packaging substrate is bonded to one side of the support layer for connection with external circuitry. The other side of the support layer is bonded to the main surface of the device chip. The support layer has conductive vias containing conductive metal. One side of the packaging substrate has bump pads bonded to the conductive metal. The length of the bump pads is less than the diameter of the vias. In a direction perpendicular to the support layer, the sum of the thickness of the bump pads and the thickness of the conductive metal is greater than the height of the conductive vias. With this elastic wave device, the traditional WLP packaging structure has a high manufacturing cost, and delamination is prone to occur at the junction of the roof layer and the support layer. This embodiment reduces the manufacturing cost of the WLP packaging structure while ensuring the frequency stability and quality factor of the elastic wave device.

[0022] Details of one or more embodiments of this application are set forth in the following drawings and description to make other features, objects and advantages of this application more readily apparent. Attached Figure Description

[0023] The accompanying drawings, which are provided to further illustrate this application and form part of this application, illustrate exemplary embodiments of this application and are used to explain this application, but do not constitute an undue limitation of this application.

[0024] Figure 1 This is a cross-sectional view of an elastic wave device according to an embodiment of this application;

[0025] Figure 2 This is a cross-sectional view of an elastic wave device according to an embodiment of this application;

[0026] Figure 3 This is a cross-sectional view of an elastic wave device according to an embodiment of this application;

[0027] Figure 4 It is along Figure 3 A top view of an elastic wave device with a horizontal cut along the AA direction;

[0028] Figures 5-12 This is a flowchart illustrating the fabrication method of the elastic wave device of this application.

[0029] In the figure: 100, device chip; 100a, main surface of device chip; 110, IDT electrode; 120, electrode pad; 130, piezoelectric substrate; 200, packaging substrate; 300, support layer; 400, conductive metal; 410, metal bump; 420, columnar metal; 430, seed layer; 500, bump pad; 600, insulating layer; 700, protective layer; M1, mask; P, photoresist pattern. Detailed Implementation

[0030] To better understand the purpose, technical solution, and advantages of this application, the application is described and illustrated below in conjunction with the accompanying drawings and embodiments.

[0031] Unless otherwise defined, the technical or scientific terms used in this application shall have the general meaning as understood by one of ordinary skill in the art to which this application pertains. Words such as “a,” “an,” “an,” “the,” “the,” and “these,” used in this application, do not indicate quantitative limitation and may be singular or plural. The terms “comprising,” “including,” “having,” and any variations thereof used in this application are intended to cover non-exclusive inclusion; for example, a process, method, system, product, or device that comprises a series of steps or modules (units) is not limited to the listed steps or modules (units) but may include steps or modules (units) not listed, or may include other steps or modules (units) inherent to such processes, methods, products, or devices. The terms “connected,” “linked,” and “coupled,” used in this application, are not limited to physical or mechanical connections but may include electrical connections, whether direct or indirect. The term “multiple” used in this application refers to two or more. The "and / or" operator describes the relationship between related objects, indicating that three relationships can exist. For example, "A and / or B" can represent three cases: A alone, A and B simultaneously, and B alone. Typically, the character " / " indicates that the objects before and after it are in an "or" relationship. The terms "first," "second," and "third," etc., used in this application are merely for distinguishing similar objects and do not represent a specific ordering of the objects.

[0032] The following is based on Figures 1 to 12 The elastic wave device of this application will be described.

[0033] Figure 1 This is a cross-sectional view of an elastic wave device according to an embodiment of this application, as shown below. Figure 1 As shown, the elastic wave device includes a device chip 100, a packaging substrate 200, and a support layer 300. The device chip 100 has electrode pads 120. One side of the packaging substrate 200 is bonded to one side of the support layer 300 for connection to an external circuit. The other side of the support layer 300 is bonded to the main surface 100a of the device chip 100. The support layer 300 has conductive vias. Conductive metal 400 and electrode pads 120 are present in the conductive vias, wherein the conductive metal 400 is formed on the electrode pads 120. One side of the packaging substrate has a bump pad 500, which is bonded to the conductive metal 400. The length of the bump pad 500 is less than the diameter of the conductive via. In a direction perpendicular to one side of the support layer 300, the sum of the thicknesses of the bump pad 500, the conductive metal 400, and the electrode pad 120 is greater than the height of the conductive via.

[0034] Specifically, the aforementioned device chip 100 is a quadrilateral plate with a side length of 0.2mm to 1.0mm and a thickness of 0.15mm to 0.2mm, used to form and propagate elastic waves; the support layer 300 has a height of 1.5μm to 65μm, and its constituent materials include, but are not limited to, silicon oxide, silicon nitride, or PI (polyimide); one side of the packaging substrate 200 is bonded to one side of the support layer 300, its main constituent material is resin, and it also contains electronic components; the other side of the packaging substrate 200 has external connection terminals (not shown in the figure), and the elastic wave device is electrically connected to an external circuit through the external connection terminals on the packaging substrate 200 and the aforementioned electronic components. The diameter of the conductive vias in the support layer 300 is 3μm to 46μm, and the constituent material of the conductive metal 400 in the conductive vias includes at least one of copper, nickel, and tin-silver alloy. The constituent material of the electrode pads 120 includes at least one of aluminum, copper, nickel, gold, and platinum. The thickness of the bump pad 500 located on one side of the packaging substrate is 0.02μm to 63μm, and its length is less than the diameter of the conductive via. When one side of the packaging substrate 200 is joined to one side of the support layer 300, the bump pad 500 is located within the conductive via. Since the sum of the thicknesses of the bump pad 500, the conductive metal 400, and the electrode pad 120 is greater than the height of the conductive via, the conductive metal 400 is melted during the reflow soldering process, causing the bump pad 500 to be partially embedded in the conductive metal 400. This ensures that the bump pad 500 is in full contact with the conductive metal 400 within the conductive via, thereby ensuring the reliability of the electrical connection between the bump pad 500 and the conductive metal 400. Furthermore, the device chip 100, the support layer 300, and the packaging substrate 200 together form a sealed space to ensure the frequency stability and quality factor of the elastic wave device.

[0035] Compared to the traditional WLP packaging structure, the above-mentioned elastic wave device does not require the formation of a roof layer. It forms a sealed space only through the device chip 100, the support layer 300, and the packaging substrate 200, thus saving packaging costs. Furthermore, when the support layer 300 is made of silicon oxide or silicon nitride, it can prevent delamination at the junction of the packaging substrate 200 and the support layer 300, thereby improving the sealing performance of the sealed space.

[0036] Figure 2 This is a cross-sectional view of an elastic wave device according to an embodiment of this application, as shown below. Figure 2 As shown, the conductive metal includes metal bumps 410, columnar metal 420, and seed layer 430; metal bumps 410 are formed above columnar metal 420; seed layer 430 is formed at the bottom of columnar metal 420 and on the inner wall of conductive via.

[0037] Specifically, the columnar metal 420 is connected to the metal pad 500 on one side of the packaging substrate 200 via metal bumps 410. The columnar metal 420 enables electrical connection between the device chip 100 and the electronic components in the packaging substrate 200. The columnar metal 420 is made of conductive materials such as aluminum, copper, silver, or gold. A seed layer 430 is formed at the bottom of the columnar metal 420 and on the inner wall of the conductive via. Its constituent material includes at least one of titanium and copper. This seed layer improves the adhesion between the conductive metal 400 and the device chip 100 and acts as a protective layer to prevent corrosion of the device chip 100, thereby ensuring the reliability of the elastic wave device.

[0038] In some embodiments, the device chip 100 further includes a piezoelectric substrate 130, an IDT electrode 110, and a wiring region; the IDT electrode 110 is formed on the main surface of the piezoelectric substrate 130; the wiring region electrically connects the electrode pad 120 and the IDT electrode 110.

[0039] Specifically, Figure 3 This is a cross-sectional view of an elastic wave device according to an embodiment of this application, as shown below. Figure 3 As shown, the piezoelectric substrate 130 is a rectangular plate with a main surface 100a. The piezoelectric substrate 130 is constructed from materials with piezoelectric properties, such as lithium tantalate or lithium niobate. IDT electrodes 110 are formed on the main surface 100a of the piezoelectric substrate 130 and are composed of electrode pairs. Each electrode pair connects multiple electrode fingers to each other at one end by a busbar. These multiple electrode fingers are arranged parallel to each other in a manner that crosses the direction of elastic wave propagation. It should be noted that in some other embodiments, the piezoelectric substrate 130 is constructed by stacking a support material such as sapphire, silicon, alumina, spinel, crystal, or glass. The coefficient of thermal expansion (CTE) of the support material is lower than that of the piezoelectric substrate. Wiring area ( Figure 3 (Not shown) Electrically connect electrode pad 120 and IDT electrode 110.

[0040] In some embodiments, the combined thickness of the conductive metal 400 and the electrode pad 120 is less than the height of the conductive via.

[0041] Specifically, such as Figure 1 As shown, the total thickness h2 of the conductive metal 400 and the electrode pad 120 is less than the height h1 of the conductive via, so as to prevent the conductive metal 400 from overflowing from the conductive via, thereby ensuring the sealing performance after one side of the support layer 300 is joined with one side of the packaging substrate 200.

[0042] In some of these embodiments, the supporting layer 300 is made of silicon oxide or silicon nitride.

[0043] Specifically, silicon oxide or silicon nitride are chemically stable and have good thermal stability, and can be prepared by chemical vapor deposition (CVD) or thermal oxidation. When the above materials are used as the constituent materials of the support layer 300, delamination can be prevented at the junction of the packaging substrate 200 and the support layer 300, the sealing performance of the sealing space can be improved, and thus the reliability of the elastic wave device can be guaranteed.

[0044] In some of these embodiments, the metal bump is made of at least one of copper, nickel, and a tin-silver alloy.

[0045] Specifically, tin-silver alloy has good weldability, copper has good electrical conductivity, and nickel has good oxidation properties. The columnar metal 420 is connected to the metal pad 500 on one side of the packaging substrate 200 through the metal bump 410, thereby realizing the electrical connection between the packaging substrate 200 and the device chip 100 and improving the reliability of the electrical connection.

[0046] In some of these embodiments, the height of the support layer 300 is greater than the thickness of the electrode pad 120.

[0047] Specifically, such as Figure 3 As shown, the height of the conductive via is equal to the height of the support layer 300. The conductive via includes electrode pad 120, conductive metal 400 and bump pad 500. Therefore, the height of the support layer must be greater than the thickness of the electrode pad 120.

[0048] In some of these embodiments, one side of the packaging substrate 200 is covered with a silicon material.

[0049] Specifically, the silicon material on one side of the packaging substrate 200 has strong adhesion to the constituent material (silicon oxide or silicon nitride) of the support layer 300, thus improving the adhesion of the bonding surface between the packaging substrate 200 and the support layer 300.

[0050] In some of these embodiments, conductive metal covers one side of the electrode pad 120 and the wiring area 140.

[0051] Specifically, Figure 4 yes Figure 3 A top view of an elastic wave device horizontally cut along the AA direction, as shown below. Figure 4 As shown, conductive metal 400 covers one side of electrode pad 120 and wiring area 140 to increase the contact area between the metals. According to R = ρL / S, where R is the resistance value, ρ is the resistivity of the conductive metal, L is the length of the conductive metal, and S is the contact area between the conductive metal and the wiring area, when the contact area S increases, the resistance of the conductive metal decreases, thereby ensuring the electrical performance of the elastic wave device.

[0052] The elastic wave device of this application will be described below through preferred embodiments.

[0053] The elastic wave device of this preferred embodiment includes a device chip 100, a packaging substrate 200, and a support layer 300. The device chip 100 has electrode pads 120. One side of the packaging substrate 200 is bonded to one side of the support layer 300 for connection to an external circuit. The other side of the support layer 300 is bonded to the main surface 100a of the device chip 100. The support layer 300 has conductive vias. Conductive metal 400 and electrode pads 120 are present in the conductive vias, wherein the conductive metal 400 is formed on the electrode pads 120. One side of the packaging substrate 200 has bump pads 500, which are bonded to the conductive metal 400. The length of the bump pads 500 is less than the diameter of the conductive vias. In a direction perpendicular to one side of the support layer 300, the sum of the thicknesses of the bump pads 500, the conductive metal 400, and the electrode pads 120 is greater than the height of the conductive vias.

[0054] The conductive metal 400 includes metal bumps 410, columnar metal 420, and a seed layer 430; the metal bumps 410 are formed above the columnar metal 420; the seed layer 430 is formed at the bottom of the columnar metal 420 and on the inner wall of the conductive via. The device chip 100 includes a piezoelectric substrate 130, an IDT electrode 110, and a wiring region; the IDT electrode 110 is formed on the main surface of the piezoelectric substrate 130; the electrode pad 120 is formed on the main surface of the piezoelectric substrate 130 and is bonded to the conductive metal 400; the wiring region connects the electrode pad 120 and the IDT electrode 110. The sum of the thicknesses of the conductive metal 400 and the electrode pad 120 is less than the height of the conductive via. The support layer 300 is made of silicon oxide or silicon nitride. The metal bumps 410 are made of at least one of copper, nickel, and a tin-silver alloy. The height of the support layer 300 is greater than the thickness of the electrode pad 120. One side of the packaging substrate 200 is covered with silicon material. Conductive metal 400 covers one side of electrode pad 120 and the wiring area.

[0055] Compared to the conventional WLP packaging structure, the elastic wave device of the above preferred embodiment does not require the formation of a roof layer. Instead, it forms a sealed space only through the device chip 100, the support layer 300, and the packaging substrate 200, thus saving packaging costs. Furthermore, when the support layer 300 is made of silicon oxide or silicon nitride, delamination at the junction of the packaging substrate 200 and the support layer 300 can be prevented, thereby improving the sealing performance of the sealed space.

[0056] Figures 5 to 12 This is a flowchart illustrating the fabrication method of the elastic wave device of this utility model. The specific steps are as follows:

[0057] S1, as Figure 5As shown, an insulating layer 600, made of silicon nitride or silicon oxide and with a thickness of 1.5 μm to 65 μm, is formed on a piezoelectric substrate 130 by chemical vapor deposition.

[0058] S2, as Figure 6 As shown, a mask M1 is designed, and a photoresist pattern P is formed on the insulating layer 600 through coating, exposure, and development processes.

[0059] S3, as Figure 7 As shown, the insulating layer 600 is dry etched based on the photoresist pattern P to form the support layer 300, and then the photoresist pattern P is removed by a photoresist removal process.

[0060] S4, such as Figure 8 As shown, a mask M2 is designed, and an IDT electrode 110 is formed through coating, exposure, development, and evaporation processes.

[0061] S5, such as Figure 9 As shown, a protective layer 700 is formed by chemical vapor deposition and dry etching processes to prevent the IDT electrode 110 from being oxidized.

[0062] S6, such as Figure 10 As shown, electrode pads 120 are formed by designing a mask (not shown in the figure) and through coating, exposure, development and vapor deposition processes.

[0063] S7, such as Figure 11 As shown, a seed layer 430, columnar metal 420, and metal bumps 410 are formed sequentially by electroplating.

[0064] S8, such as Figure 12 As shown, the bump pads 500 on the packaging substrate 200 are connected to the metal bumps 410 through processes such as reflow soldering, grinding and cutting, so that one side of the packaging substrate 200 is joined to one side of the support layer 300 to form the elastic wave device of this application.

[0065] Compared with the traditional WLP packaging structure, the elastic wave device obtained by the above method does not require the formation of a roof layer. It only forms a sealed space through the device chip 100, the support layer 300 and the packaging substrate 200, which saves packaging costs. Moreover, when the supporting layer 300 is made of silicon oxide or silicon nitride, it can prevent delamination at the junction of the packaging substrate 200 and the support layer 300, thereby improving the sealing performance of the sealed space.

[0066] This invention also provides a module comprising multiple elastic wave devices and a sealing portion, which seals the elastic wave devices and other components. This module enables the transmission and reception of signals in a wireless communication system.

[0067] The expressions and terms used in this utility model are for illustrative purposes only and should not be considered limiting. The use of "comprising," "possessing," "having," "including," and variations thereof as used herein means to include the following items, their equivalents, and additional items.

[0068] The term "embodiment" in this application refers to a specific feature, structure, or characteristic described in connection with an embodiment that may be included in at least one embodiment of this application. The appearance of this phrase in various places in the specification does not necessarily imply the same embodiment, nor does it imply that it is mutually exclusive with or independent of other embodiments. It will be clearly or implicitly understood by those skilled in the art that the embodiments described in this application may be combined with other embodiments without conflict.

[0069] 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 patent protection. It should be noted that those skilled in the art can make various modifications, alterations, and improvements without departing from the concept of this application, and these all fall within the scope of protection of this application. Therefore, the scope of protection of this application should be determined by the appended claims.

Claims

1. An elastic wave device, characterized in that, It includes a device chip, a packaging substrate, and a support layer, wherein the device chip has electrode pads, characterized in that: One side of the packaging substrate is joined to one side of the support layer for connection with external circuitry; The other side of the support layer is bonded to the main surface of the device chip; the support layer has conductive vias; the conductive vias have conductive metal and electrode pads, wherein the conductive metal is formed on the electrode pads; One side of the packaging substrate has a bump pad, which is bonded to the conductive metal; the length of the bump pad is less than the diameter of the conductive via; in a direction perpendicular to the side of the support layer, the sum of the thicknesses of the bump pad, the conductive metal, and the electrode pad is greater than the height of the conductive via.

2. The elastic wave device according to claim 1, characterized in that, The conductive metal includes metal bumps, columnar metal, and a seed layer; The metal bump is formed above the columnar metal; the seed layer is formed at the bottom of the columnar metal and on the inner wall of the conductive via.

3. The elastic wave device according to claim 1, characterized in that, The device chip also includes a piezoelectric substrate, IDT electrodes, and wiring areas; The IDT electrode is formed on the main surface of the piezoelectric substrate; The wiring area electrically connects the electrode pads and the IDT electrodes.

4. The elastic wave device according to claim 1, characterized in that, The sum of the thicknesses of the conductive metal and the electrode pads is less than the height of the conductive via.

5. The elastic wave device according to claim 1, characterized in that, The supporting layer is made of silicon oxide or silicon nitride.

6. The elastic wave device according to claim 2, characterized in that, The metal bump is made of at least one of copper, nickel, and tin-silver alloy.

7. The elastic wave device according to claim 3, characterized in that, The height of the support layer is greater than the thickness of the electrode pads.

8. The elastic wave device according to claim 1, characterized in that, One side of the packaging substrate is covered with silicon material.

9. The elastic wave device according to claim 3, characterized in that, The conductive metal covers one side of the electrode pad and the wiring area.

10. A module, characterized in that, Including the elastic wave device as described in any one of claims 1-9.

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