Elastic wave device

Abstract

The invention relates to an elastic wave device. A metal pattern includes a resonator, a metal wiring, an electrode pad, and an alignment mark metal. The electrode pad and the resonator are connected through the metal wire; a support part which surrounds the resonator, the metal wiring, and the electrode pad and is made of an insulating material; the alignment mark metal is located outside the supporting part and is electrically isolated; the minimum distance between the supporting part and the alignment mark metal is larger than or equal to the preset first distance, and through the elastic wave device, the problem that in order to meet the requirements for miniaturization and material performance of the elastic wave device, a traditional WLP packaging technology is low in alignment mark recognition accuracy is solved, and the alignment mark recognition accuracy is improved. And the alignment mark identification accuracy of the elastic wave device is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of semiconductor packaging, and particularly to an elastic wave device. Background Art

[0002] In the wafer level packaging (WLP) technology of elastic wave devices, in order to facilitate identification and assembly, the positions of the pad bumps on the elastic wave device are usually made asymmetric, or a metal film with a preset shape is formed on the cover layer of the chip to be used for setting the position of the alignment mark on the elastic wave device chip. However, with the gradual increase in the requirements for miniaturization and material performance of elastic wave devices, it is technically difficult to set the positions of the pad bumps asymmetrically, and the alignment recognition accuracy is relatively low; while forming a metal film with a preset shape on the cover layer of the elastic wave device requires more man-hours, thereby reducing the alignment recognition efficiency of the elastic wave device.

[0003] Regarding the problem that the recognition accuracy of the alignment mark is relatively low in order to meet the requirements of miniaturization and material performance of elastic wave devices, there is currently no suitable solution. Summary of the Invention

[0004] In the present invention, an elastic wave device is provided to solve the problem that the recognition accuracy of the alignment mark is relatively low in the traditional WLP packaging technology in order to meet the requirements of miniaturization and material performance of elastic wave devices.

[0005] In a first aspect, in the present embodiment, an elastic wave device is provided, including a piezoelectric substrate, a metal pattern formed on the piezoelectric substrate, and a support portion.

[0006] The metal pattern includes a resonator, metal wirings, electrode pads, and alignment mark metals.

[0007] Between the electrode pads and the resonator, they are connected through the metal wirings.

[0008] The support portion surrounds the resonator, the metal wirings, and the electrode pads, and its constituent material is an insulating material.

[0009] The alignment mark metals are located outside the support portion and are electrically isolated.

[0010] The minimum distance between the support portion and the alignment mark metals is greater than or equal to a preset first distance.

[0011] In some of the embodiments, the support portion has a first chamfered edge at the closest position to the alignment mark metals.

[0012] The minimum distance between the first chamfered edge and the alignment mark metal is greater than or equal to a preset first distance.

[0013] In some embodiments, the minimum distance between the alignment mark metal and the edge of the piezoelectric substrate is 5 μm to 30 μm.

[0014] In some embodiments, the shape of the alignment mark metal includes a triangle, a rectangle, a circle, a semicircle, or a polygon.

[0015] In some embodiments, the alignment mark metal has a hypotenuse parallel to the first chamfered edge.

[0016] In some embodiments, the target electrode pad is set as the electrode pad closest to the alignment mark metal; the target electrode pad has a second chamfered edge to make the electrical clearance between it and the alignment mark metal greater than or equal to a preset second distance.

[0017] In some embodiments, the electrical clearance between the target electrode pad and the alignment mark metal is equal to the minimum distance between the second chamfered edge and the alignment mark metal.

[0018] In some embodiments, the first chamfered edge is parallel to the second chamfered edge.

[0019] In some embodiments, the alignment mark metal includes a reflective layer and an adhesion layer, and the reflective layer is laminated on the adhesion layer.

[0020] In some embodiments, the constituent material of the reflective layer includes platinum, palladium, aluminum, copper, or molybdenum; the constituent material of the adhesion layer is titanium.

[0021] Compared with the related art, in this embodiment, an elastic wave device is provided, which includes a piezoelectric substrate, a metal pattern formed on the piezoelectric substrate, and a support portion. The metal pattern includes a resonator, a metal wiring, an electrode pad, and an alignment mark metal; the electrode pad and the resonator are connected by the metal wiring; the support portion surrounds the resonator, the metal wiring, and the electrode pad, and its constituent material is an insulating material; the alignment mark metal is located outside the support portion and is electrically isolated; the minimum distance between the support portion and the alignment mark metal is greater than or equal to a preset first distance. Through the above elastic wave device, the problem that the alignment mark recognition accuracy is relatively low in the traditional WLP packaging technology to meet the miniaturization and material performance requirements of the elastic wave device is solved, and the accuracy of alignment mark recognition is improved.

[0022] Details of one or more embodiments of the present application are set forth in the following drawings and description to make other features, objects, and advantages of the present application more concise and understandable. Description of the Drawings

[0023] The accompanying drawings described herein are used to provide a further understanding of the present application and constitute a part of the present application. The schematic embodiments of the present application and their descriptions are used to explain the present application and do not constitute an improper limitation of the present application.

[0024] Figure 1 Schematic structure of the elastic wave device according to the first embodiment of the present application Figure 1 ;

[0025] Figure 2 Schematic structural diagram of the support part according to an embodiment of the present application;

[0026] Figure 3 Schematic structure of the elastic wave device according to the first embodiment of the present application Figure 2 ;

[0027] Figure 4 Cross-sectional view of the elastic wave device according to the first embodiment of the present application;

[0028] Figure 5 is Figure 1 Partial enlarged view of the electrode pad and the alignment mark metal in

[0029] Figure 6 Schematic structural diagram of the elastic wave device according to an embodiment of the present application;

[0030] Figure 7 Schematic structural diagram of the elastic wave device according to an embodiment of the present application;

[0031] Figure 8 Schematic structural diagram of the elastic wave device according to the second embodiment of the present application;

[0032] Figure 9 Partial enlarged view of the elastic wave device according to the second embodiment of the present application.

[0033] In the figure: 100, piezoelectric substrate; 200, resonator; 210, rectangular through-hole; 220, IDT electrode; 300, metal wiring; 400, support part; 400c, first chamfered edge; 500, pad electrode; 500c, second chamfered edge; 520, circular through-hole; 530, conductive metal; 540, bump; 600, alignment mark metal; 610, reflective layer; 620, adhesive layer; 700, cover layer; a, b, right-angle sides; c, hypotenuse; L1, minimum distance between the alignment mark metal and the support part; L2, minimum distance between the alignment mark metal and the target electrode pad; L3, L4, minimum distance between the alignment mark metal and the edge of the piezoelectric substrate. Detailed implementation manners

[0034] To more clearly understand the purpose, technical solution, and advantages of this application, the following describes and explains this application in conjunction with the accompanying drawings and embodiments.

[0035] Unless otherwise defined, the technical terms or scientific terms involved in this application shall have the general meaning understood by those with ordinary skills in the technical field to which this application belongs. In this application, words such as "a", "one", "a kind of", "the", "these", etc. do not indicate a limitation in quantity, and they can be singular or plural. The terms "include", "comprise", "have" and any variants thereof involved in this application are intended to cover non-exclusive inclusion; for example, a process, method, system, product, or device that includes a series of steps or modules (units) is not limited to the listed steps or modules (units), but may include unlisted steps or modules (units), or may include other steps or modules (units) inherent in these processes, methods, products, or devices. The terms "connect", "be connected", "couple" and other similar words involved in this application are not limited to physical or mechanical connections, but may include electrical connections, whether directly or indirectly connected. The "plurality" involved in this application means two or more. "And / or" describes the association relationship of associated objects and indicates that three relationships may exist. For example, "A and / or B" may mean: A exists alone, A and B exist simultaneously, and B exists alone. Usually, the character " / " indicates that the objects associated before and after are in an "or" relationship. The terms "first", "second", "third", etc. involved in this application are only used to distinguish similar objects and do not represent a specific order for the objects.

[0036] Hereinafter, based on Figures 1 to 9 , the elastic wave device of this application will be described.

[0037] The following describes the implementation manners with reference to the accompanying drawings. In each figure, the same or corresponding parts are marked with the same reference numerals. For parts with repeated descriptions, appropriate simplification or omission will be made.

[0038] Figure 1 The structural schematic of the elastic wave device according to the first embodiment of this application Figure 1 is as Figure 1As shown in the figure, the elastic wave device includes a piezoelectric substrate 100 and a metal pattern formed on the piezoelectric substrate 100. The metal pattern includes a resonator 200, a metal wiring 300, an electrode pad 500, and an alignment mark metal 600. The electrode pad 500 is connected to the resonator 200 through the metal wiring 300. In addition to the above structure, the elastic wave device of the present application further includes a support portion, which surrounds the resonator 200, the metal wiring 300, and the electrode pad 500, and its constituent material is an insulating material; the alignment mark metal is located outside the support portion and is electrically isolated; the minimum distance between the support portion and the alignment mark metal 400 is greater than or equal to a preset first distance, and the first distance is preset to 5 μm.

[0039] Figure 2 It is a schematic structural diagram of the support portion according to an embodiment of the present application. As Figure 2 shown, the support portion 400 has a circular through-hole 520 and a rectangular through-hole 210, and a first chamfered edge 400c, and its constituent material is an insulating material. Figure 3 It is a schematic structural diagram of the elastic wave device according to the first embodiment of the present application Figure 2 , as Figure 3 shown, the support portion 400 is formed on the piezoelectric substrate 100 by photolithography technology and surrounds the resonator 200, the metal wiring 300, and the electrode pad 500; the alignment mark metal 600 is located outside the support portion 400 and is electrically isolated; the closest position of the support portion 400 to the alignment mark metal 600 is the first chamfered edge 400c. By setting the first chamfered edge 400c, the minimum distance L1 between the alignment mark metal 600 and the support portion 400 is greater than or equal to the preset first distance. Figure 4 It is a cross-sectional view of the elastic wave device according to the first embodiment of the present application cut along the perpendicular bisector of the first chamfered edge. As Figure 4 shown, the elastic wave device further includes a cover layer 700, a conductive metal 530, and a bump 540. Among them, the constituent material of the cover layer 700 is an insulating material such as resin, which covers the support portion 400 and has a through-hole with a diameter larger than that of the circular through-hole 520 above the circular through-hole 520; the circular through-hole 520 is located at the electrode pad 500, and the conductive metal 530 is injected into the through-hole of the cover layer 700 and the circular through-hole 520 to electrically connect the conductive metal 530 to the electrode pad 500; the rectangular through-hole 210 is located at the resonator 200, and the piezoelectric substrate 100, the support portion 400, and the cover layer 700 form a sealed cavity at the resonator 200, so that the IDT electrode 220 in the resonator 200 is located in the sealed cavity. This sealed cavity can effectively reduce the leakage of elastic wave energy, thereby ensuring the Q value (quality factor) of the elastic wave device; the bump 540 is joined to the conductive metal 530, and its constituent material is a metal material such as tin or copper, which is used to realize the electrical connection between the elastic wave device and the external circuit.

[0040] Specifically, the above elastic wave device has a flat hexahedron structure, including a plurality of resonators 200. The resonators 200 include a set of IDT electrodes 220 that are oppositely arranged and staggeredly distributed, and the thickness range thereof is 0.25 mm to 0.35 mm. The metal wiring 300 is used to realize the electrical connection between the resonator 200 and the electrode pad 500, and then through the electrode pad 500 to realize the electrical connection between the elastic wave device and the external circuit. The support portion 400 is made of an insulating material such as resin, and its thickness in the direction orthogonal to the main surface of the piezoelectric substrate 100 is 10 μm to 30 μm. The above IDT electrodes, electrode pads 500, and metal wiring 300 are all formed by photolithography and evaporation processes. The piezoelectric substrate 100 is made of lithium tantalate or lithium niobate, and its thickness is 100 μm to 450 μm. It should be noted that in other embodiments, the elastic wave device further includes a support substrate, and the piezoelectric substrate 100 is laminated on the support substrate. The support substrate is made of sapphire, silicon, alumina, spinel, quartz, or glass, etc. The alignment mark metal 600 is formed together with the electrode pad 500 forming process, which simplifies the process steps of forming the alignment mark metal 600. Since the alignment mark metal 600 is a metal material, it needs to be electrically isolated from metal components such as the resonator 200, metal wiring 300, and electrode pad 500 to prevent short circuits or arc discharges caused by air breakdown. The alignment mark metal 600 is located outside the support portion 400, and the spacing distance L1 between it and the nearest electrode pad 500 is greater than or equal to the first distance, and the first distance is preset to 5 μm. The alignment mark metal 600 can be automatically recognized by providing a surface mount technology (SMT) machine, without manual judgment, thereby improving the alignment recognition efficiency.

[0041] Compared with the traditional WLP packaging structure, the above elastic wave device forms an alignment mark metal 600 that satisfies electrical isolation outside the support portion 400; a first chamfer edge is provided at the nearest position of the support portion 400 to the alignment mark metal 600, so that the spacing distance L1 between it and the nearest electrode pad 500 is greater than or equal to the first distance, while ensuring that the elastic wave device meets the requirements of miniaturization and material performance, improving the recognition accuracy of the alignment mark, and the reliability of the elastic wave device.

[0042] In some of these embodiments, the minimum distance between the alignment mark metal 600 and the edge of the piezoelectric substrate 100 is 5 μm to 30 μm.

[0043] Specifically, Figure 5 For Figure 1 the partial enlarged view of the middle electrode pad and the alignment mark metal, as Figure 5 ​As shown, L3 and L4 are the distances between the alignment mark metal 600 and the edge of the piezoelectric substrate 100. The smaller value of L3 and L4 is the minimum distance between the alignment mark metal 600 and the edge of the piezoelectric substrate 100. This minimum distance is controlled within 5μm to 30μm to prevent the alignment mark metal 600 from being damaged during the manufacturing process, thereby ensuring the effectiveness of subsequent alignment recognition.

[0044] In some of these embodiments, when ensuring that the minimum distance L1 between the alignment mark metal 600 and the support portion 400 is greater than or equal to the first distance, and the minimum distance between the alignment mark metal 600 and the edge of the piezoelectric substrate 100 is 5μm to 30μm, the shape of the alignment mark metal 600 includes a triangle, a rectangle, a circle, a semi-circle, or a polygon. Among them, Figure 1 where the alignment mark metal 600 is a triangle, Figure 6 where the alignment mark metal 600 is a circle, Figure 7 where the alignment mark metal 600 is a rectangle.

[0045] In some of these embodiments, the alignment mark metal 600 has a hypotenuse parallel to the first chamfered edge 400c.

[0046] Specifically, as Figure 5 shown, the alignment mark metal 600 is a right triangle. Among them, the right side a and the right side b are respectively parallel to the edge of the piezoelectric substrate 100 closest to them, the hypotenuse c is parallel to the first chamfered edge 400c, the inclination angle α between the hypotenuse c and the horizontal direction is between 30° and 60°, preferably the inclination angle is 45°, and the length ranges of the right side a and the right side b are 20μm to 60μm. In this embodiment, the lengths of both the right side a and the right side b are 42.5μm. Therefore, the spacing distance L1 between the hypotenuse c and the first chamfered edge 400c is the minimum distance between the alignment mark metal 600 and the support portion 400. When the above spacing distance L1 satisfies being greater than or equal to the first distance, and the minimum distance between the alignment mark metal 600 and the edge of the piezoelectric substrate 100 is 5μm to 30μm, setting the hypotenuse c of the alignment mark metal 600 to be parallel to the first chamfered edge 400c can maximize the graphic area of the alignment mark metal 600 enclosed by the right side a, the right side b, and the hypotenuse c, thereby improving the recognition accuracy of the alignment mark metal 600.

[0047] In some of these embodiments, the target electrode pad is set as the electrode pad 500 closest to the alignment mark metal 600; the target electrode pad has a second chamfered edge to make its electrical clearance from the alignment mark metal greater than or equal to a preset second distance.

[0048] Specifically, Figure 8 is a schematic structural diagram of the elastic wave device according to the second embodiment of the present application. AsFigure 8 As shown, in order to prevent breakdown discharge caused by too small a distance between the alignment mark metal 600 and the target electrode pad closest to it, the electrical clearance L2 between the alignment mark metal 600 and the target electrode pad needs to be greater than or equal to a preset second distance, where the second distance is preset to be greater than 6 μm. By providing a second chamfered edge 500c on the target electrode pad, the elastic wave device expands the electrical clearance between the alignment mark metal 600 and the target electrode pad while maintaining the original size, so as to prevent breakdown discharge of the elastic wave device due to too small an electrical clearance, thereby ensuring the reliability of the elastic wave device. Among them, the electrical clearance between the above-mentioned target electrode pad and the alignment mark metal 600, that is, the minimum distance between the second chamfered edge 500c and the alignment mark metal 600.

[0049] In some of these embodiments, the first chamfered edge 400c is parallel to the second chamfered edge 500c. Figure 9 This is a partial enlarged view of the elastic wave device according to the second embodiment of the present application. As Figure 9 shown, the first chamfered edge 400c and the second chamfered edge 500c have the same inclination angle in the horizontal direction, and the range is between 30° and 60°, preferably the inclination angle is 45°. In this embodiment, on the basis of providing the first chamfered edge 400c, a second chamfered edge 500c is also provided on the target electrode pad, expanding the electrical clearance between the alignment mark metal 600 and the target electrode pad, and further improving the electrical isolation effectiveness of the alignment mark metal 600.

[0050] As Figure 4 shown, in some of these embodiments, the alignment mark metal 600 includes a reflective layer 610 and an adhesion layer 620. Among them, the reflective layer 610 is laminated on the adhesion layer 620, and its constituent materials include platinum, palladium, aluminum, copper or molybdenum to improve the accuracy of identifying the alignment mark metal 600; the constituent material of the adhesion layer 620 is titanium to enhance the adhesion of the alignment mark metal 600.

[0051] The elastic wave device of the present application will be described below through a first preferred embodiment.

[0052] As Figure 3As shown in the figure, the elastic wave device of the present preferred embodiment includes a piezoelectric substrate 100, a metal pattern formed on the piezoelectric substrate 100, and a support portion 400. Among them, the material of the piezoelectric substrate 100 is lithium tantalate. The metal pattern includes a resonator 200, a metal wiring 300, an electrode pad 500, and an alignment mark metal 600. The electrode pad 500 is connected to the resonator 200 through the metal wiring 300. The support portion 400 surrounds the resonator 200, the metal wiring 300, and the electrode pad 500, and its constituent material is a resin material. The alignment mark metal is located outside the support portion 400 and is electrically isolated. The support portion 400 has a first chamfered edge 400c at the closest position to the alignment mark metal 600, so that the minimum distance L1 from it to the alignment mark metal 600 is greater than or equal to a preset first distance, and the first distance is preset to 5 μm. The shape of the alignment mark metal 600 is an isosceles right triangle with a right-angled side length of 42.5 μm, and its hypotenuse is parallel to the first chamfered edge 400c. The minimum distance between the alignment mark metal and the edge of the piezoelectric substrate is 5 μm. The alignment mark metal 600 includes a reflective layer and an adhesion layer. The reflective layer is laminated on the adhesion layer, and the constituent material of the reflective layer includes platinum, palladium, aluminum, copper, or molybdenum, and the constituent material of the adhesion layer is titanium.

[0053] The elastic wave device of the present application will be described below through a second preferred embodiment.

[0054] As Figure 8 shown in the figure, in addition to having the structure of the elastic wave device of the above first preferred embodiment, the elastic wave device of the present second preferred embodiment sets the electrode pad 500 closest to the alignment mark metal 600 as the target electrode pad, and the target electrode pad has a second chamfered edge 500c to make the electrical clearance L2 between it and the alignment mark metal 600 greater than or equal to a preset second distance, and the second distance is preset to 6 μm. The electrical clearance between the target electrode pad and the alignment mark metal 600, that is, the minimum distance between the second chamfered edge 500c and the alignment mark metal 600, and the first chamfered edge 400c is parallel to the second chamfered edge 500c.

[0055] For the elastic wave devices of the above first preferred embodiment and the second preferred embodiment, by setting the first chamfered edge on the support portion 400 and the second chamfered edge 500c on the target electrode pad, while ensuring the electrical isolation effectiveness of the alignment mark metal 600, the area of the alignment mark metal 600 is maximized, thereby solving the problem that the recognition accuracy of the alignment mark is relatively low in the traditional WLP packaging technology to meet the requirements of miniaturization and material performance of the elastic wave device, and improving the accuracy of the alignment mark recognition of the elastic wave device.

[0056] The expressions and terms used in the present invention are for illustrative purposes only and should not be construed as limiting. The use of "including", "having", "comprising", "containing" and their variants herein means including the items listed below, their equivalents and additional items.

[0057] The term "embodiment" in this application means that the specific features, structures or characteristics described in connection with the embodiments may be included in at least one embodiment of this application. The phrase appears in various positions in the specification and does not necessarily mean the same embodiment, nor does it mean being independent or alternative to other embodiments and mutually exclusive. Those of ordinary skill in the art can clearly or implicitly understand that the embodiments described in this application can be combined with other embodiments without conflict.

[0058] The above-described embodiments merely represent several implementation manners of this application, and their descriptions are relatively specific and detailed, but should not be construed as a limitation on the scope of patent protection. It should be noted that for those of ordinary skill in the art, without departing from the concept of this application, several deformations, corrections and improvements can still be made, and these all belong to the protection scope of this application. Therefore, the protection scope of this application shall be subject to the appended claims.

Claims

1. An elastic wave device, comprising a piezoelectric substrate, a metal pattern formed on the piezoelectric substrate, and a support portion, characterized in that: The metal pattern includes a resonator, a metal wiring, an electrode pad, and an alignment mark metal; The electrode pad is connected to the resonator through the metal wiring; The support portion surrounds the resonator, the metal wiring, and the electrode pad, and is made of an insulating material; The alignment mark metal is located outside the support portion and is electrically isolated; The minimum distance between the support portion and the alignment mark metal is greater than or equal to a preset first distance.

2. The elastic wave device according to claim 1, characterized in that: The support portion has a first chamfered edge at a position closest to the alignment mark metal; The minimum distance between the first chamfered edge and the alignment mark metal is greater than or equal to a preset first distance.

3. The elastic wave device according to claim 1, characterized in that: The minimum distance between the alignment mark metal and the edge of the piezoelectric substrate is 5 μm to 30 μm.

4. The elastic wave device according to claim 1, characterized in that: The shape of the alignment mark metal includes triangle, rectangle, circle, semicircle or polygon.

5. The elastic wave device according to claim 2, characterized in that: The alignment mark metal has a beveled edge parallel to the first chamfered edge.

6. The elastic wave device according to claim 2, characterized in that: The target electrode pad is set as the electrode pad closest to the alignment mark metal; the target electrode pad has a second chamfered edge so that the electrical gap between the target electrode pad and the alignment mark metal is greater than or equal to a preset second distance.

7. The elastic wave device according to claim 6, characterized in that: The electrical gap between the target electrode pad and the alignment mark metal is equal to the minimum distance between the second chamfered edge and the alignment mark metal.

8. The elastic wave device according to claim 6, characterized in that: The first chamfered edge is parallel to the second chamfered edge.

9. The elastic wave device according to claim 1, characterized in that: The alignment mark metal comprises a reflective layer and an adhesive layer, wherein the reflective layer is stacked on the adhesive layer.

10. The elastic wave device according to claim 9, characterized in that: The material constituting the light reflecting layer includes platinum, palladium, aluminum, copper or molybdenum; the material constituting the adhesion layer is titanium.

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