Bulk acoustic wave resonator, filter and manufacturing method thereof

Abstract

The invention provides a bulk acoustic wave resonator, a filter and a manufacturing method thereof. The bulk acoustic wave resonator comprises a bulk acoustic wave resonator carrier with a first resonant cavity, a first electrode layer, a piezoelectric layer, a second electrode layer and a bulk acoustic wave resonator cover body with a second resonant cavity and a heat dissipation layer, the heat dissipation layer is provided with at least one protrusion. The second electrode layer covers a first area of the first surface of the piezoelectric layer, and the first area is the surface, close to one side of the bulk acoustic resonator cover body, of the piezoelectric layer; the first electrode layer covers a second area of the second surface of the piezoelectric layer, and the second area is the surface, close to one side of the bulk acoustic resonator carrier, of the piezoelectric layer; the orthographic projection of the second area on the bulk acoustic wave resonator carrier is at least partially overlapped with the orthographic projection of the first area on the bulk acoustic wave resonator carrier. The heat dissipation layer with a special structure is arranged at a proper position, so that the heat dissipation area can be increased, the heat dissipation efficiency is improved, and the problems of poor heat dissipation effect, poor performance and the like of the bulk acoustic wave resonator are solved.

Description

Technical Field

[0001] The present application relates to the technical field of resonators, and in particular to a bulk acoustic wave resonator, a filter and a manufacturing method thereof. Background Art

[0002] At present, with the rapid development of wireless communications, there are more and more devices that send and receive information at higher frequency bands, and the requirements for RF front-end circuits are becoming more and more stringent, and the market demand for high-performance filters is increasing. Bulk acoustic wave filters are gradually becoming the mainstream of the market due to their high quality factor, good out-of-band suppression, and high rectangular coefficient.

[0003] BAW resonators generate heat during operation. The heat in the resonant region can be transferred to the outside through the upper and lower electrodes, while the heat in the non-resonant region can only be transferred to the outside through the piezoelectric layer. Since the piezoelectric layer is currently mainly made of materials with poor thermal conductivity such as AlN, the existing BAW resonator cannot achieve efficient heat dissipation.

[0004] Therefore, under the premise of ensuring good performance of the BAW resonator, how to improve its heat dissipation efficiency has become an urgent problem to be solved. Summary of the invention

[0005] The present application provides a bulk acoustic wave resonator and a manufacturing method thereof, which are used to solve the problems of poor heat dissipation effect and poor performance of the bulk acoustic wave resonator.

[0006] In a first aspect, the present application provides a bulk acoustic wave resonator, comprising: A bulk acoustic wave resonator carrier; the bulk acoustic wave resonator carrier has a first resonant cavity; In a first direction A, the piezoelectric layer and the BAW resonator cover are sequentially located on one side of the BAW resonator carrier, the first direction A is perpendicular to the plane where the BAW resonator carrier is located, and points from the BAW resonator carrier to the piezoelectric layer; the BAW resonator cover has a second resonant cavity and a heat dissipation layer; the heat dissipation layer has at least one protrusion; A second electrode layer located on a side of the piezoelectric layer close to the BAW resonator cover, the second electrode layer covering a first area of ​​a first surface of the piezoelectric layer, the first area being a surface of the piezoelectric layer close to the BAW resonator cover; A first electrode layer is located on a side of the piezoelectric layer close to the BAW resonator carrier, the first electrode layer covers a second area of ​​a second surface of the piezoelectric layer, the second area is a surface of the piezoelectric layer close to the BAW resonator carrier; an orthographic projection of the second area on the BAW resonator carrier at least partially overlaps with an orthographic projection of the first area on the BAW resonator carrier.

[0007] Preferably, the BAW resonator carrier comprises: A first substrate located on a side of the piezoelectric layer away from the BAW resonator cover; a first bonding layer located on a side of the first substrate close to the piezoelectric layer; the first bonding layer has a first protrusion and a second protrusion; in the first direction A, a height of the first protrusion is greater than a height of the second protrusion; The first resonant cavity is formed by the first bonding layer, the piezoelectric layer and the first electrode layer; The cross section of the first resonant cavity in the second direction B is L-shaped; the cross section of the second resonant cavity in the first direction A is L-shaped.

[0008] Preferably, the BAW resonator cover comprises: a second substrate located on a side of the heat dissipation layer close to the BAW resonator carrier; a first through hole and a second through hole penetrating the second substrate in the first direction A; a second bonding layer located on a side of the second substrate close to the piezoelectric layer; A pad is located on a side of the second bonding layer close to the piezoelectric layer.

[0009] Preferably, the entire surface of the heat dissipation layer on a side away from the BAW resonator carrier is in contact with the entire surface of the second substrate on a side close to the BAW resonator carrier.

[0010] Preferably, at least a portion of the surface of the heat dissipation layer on a side close to the BAW resonator carrier is in contact with a surface of the second substrate on a side away from the BAW resonator carrier; and the heat dissipation layer covers at least a portion of the surface of the second substrate on a side away from the BAW resonator carrier.

[0011] Preferably, the heat dissipation layer covers the entire surface of the second substrate on a side away from the BAW resonator carrier.

[0012] Preferably, along the second direction B, the heat dissipation layer has a third protrusion and a fourth protrusion of the same height, and the surfaces of the third protrusion and the fourth protrusion close to the piezoelectric layer are connected to at least a portion of the surface of the pad away from the piezoelectric layer, and the second direction B is parallel to the first direction A and points from the piezoelectric layer to the BAW resonator carrier.

[0013] Preferably, at least a portion of the surface of the soldering pad on a side close to the BAW resonator carrier is in contact with at least a portion of the first electrode layer; and / or at least a portion of the surface of the soldering pad on a side close to the BAW resonator carrier is in contact with at least a portion of the second electrode layer.

[0014] Preferably, there is a first distance D between the heat dissipation layer and the pad, and the first distance D>5 μm.

[0015] Preferably, the BAW resonator further comprises: a packaging connection line arranged on a side of the first electrode layer away from the piezoelectric layer.

[0016] In a second aspect, the present application further provides a filter, comprising a bulk acoustic wave resonator as described in any one of the first aspects.

[0017] In a third aspect, the present application further provides a method for manufacturing a bulk acoustic wave resonator, the method for manufacturing the bulk acoustic wave resonator described in any one of the first aspects, the method comprising: Providing a carrier substrate; forming a second electrode layer on one side of the carrier substrate; forming a piezoelectric layer on a side of the second electrode layer away from the carrier substrate; forming a first electrode layer on a side of the piezoelectric layer away from the carrier substrate; Etching the first electrode layer so that the first electrode layer covers a second area of ​​the second surface of the piezoelectric layer, where the second area is at least a portion of the surface of the piezoelectric layer on a side close to the first electrode layer; forming a first sacrificial layer on a side of the piezoelectric layer and the first electrode layer away from the carrier substrate; etching the first sacrificial layer; forming a first bonding layer on a side of the first sacrificial layer away from the carrier substrate; forming a first substrate on a side of the first bonding layer away from the carrier substrate; In the thickness direction, the BAW resonator is turned 180° and the carrier substrate is removed; Etching the second electrode layer so that the second electrode layer covers a first area of ​​a first surface of the piezoelectric layer, the first area being at least a portion of a surface of the piezoelectric layer on a side close to the second electrode layer; an orthographic projection of the first area on the BAW resonator carrier at least partially overlaps with an orthographic projection of the second area on the BAW resonator carrier; etching the piezoelectric layer; Etching pads; Placing the pad on the side of the piezoelectric layer and the first electrode layer close to the second electrode layer; removing the first sacrificial layer to form the first resonant cavity; forming a patterned second bonding layer; Placing the second bonding layer on the pad, the piezoelectric layer and the first electrode layer on a side close to the second electrode layer to form a second resonant cavity; forming a second substrate on a side of the second bonding layer away from the piezoelectric layer; etching the second bonding layer and the second substrate; forming the heat dissipation layer on a side of the pad away from the piezoelectric layer; A packaging connection line is formed on a side of the first electrode layer away from the piezoelectric layer.

[0018] Preferably, the heat dissipation layer covers at least a portion of the surface of the second substrate away from the piezoelectric layer; And / or, the heat dissipation layer covers the entire surface of the second substrate on a side away from the piezoelectric layer; And / or, the entire surface of the heat dissipation layer away from the piezoelectric layer is in contact with the entire surface of the second substrate close to the piezoelectric layer.

[0019] The BAW resonator provided by the present application includes a BAW resonator carrier having a first resonant cavity, a first electrode layer, a piezoelectric layer, a second electrode layer, and a BAW resonator cover having a second resonant cavity and a heat dissipation layer; the heat dissipation layer has at least one protrusion; the second electrode layer covers a first area of ​​the first surface of the piezoelectric layer, the first area being the surface of the piezoelectric layer close to the BAW resonator cover; the first electrode layer covers a second area of ​​the second surface of the piezoelectric layer, the second area being the surface of the piezoelectric layer close to the BAW resonator carrier; the orthographic projection of the second area on the BAW resonator carrier overlaps at least partially with the orthographic projection of the first area on the BAW resonator carrier. The present application can increase the heat dissipation area, improve the heat dissipation efficiency, avoid the resonant frequency drift of the BAW resonator, enhance the stability of the overall structure of the BAW resonator, avoid the distortion and deformation of the resonant structure of the BAW resonator, slow down the aging of the BAW resonator or damage caused by heating, and improve the reliability and service life of the thin film BAW resonator by arranging a heat dissipation layer with a special structure at an appropriate position. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to more clearly illustrate the technical solutions in the present application or the prior art, a brief introduction will be given below to the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0021] Figure 1 This is a schematic diagram of the steps provided in Example 1 of this application. Figure 1 ; Figure 2 This is a schematic diagram of the steps provided in Example 1 of this application. Figure 2 ; Figure 3 This is a schematic diagram of the steps provided in Example 1 of this application. Figure 3 ; Figure 4 This is a schematic diagram of the steps provided in Example 1 of this application. Figure 4 ; Figure 5 This is a schematic diagram of the steps provided in Example 1 of this application. Figure 5 ; Figure 6 This is a schematic diagram of the steps provided in Example 1 of this application. Figure 6 ; Figure 7 This is a schematic diagram of the steps provided in Example 1 of this application. Figure 7 ; Figure 8 This is a schematic diagram of the steps provided in Example 1 of this application. Figure 8 ; Fig. 9 This is a schematic diagram of the steps provided in Example 1 of this application. Figure 9 ; Fig.10 This is a schematic diagram of the steps provided in Example 1 of this application. Figure 10 ; Fig.11 This is a schematic diagram of the steps provided in Example 1 of this application. Figure 10 one; Fig.12 This is a schematic diagram of the steps provided in Example 1 of this application. Figure 10 two; Fig.13 This is a schematic diagram of the steps provided in Example 1 of this application. Figure 10 three; Fig.14 This is a schematic diagram of the steps provided in Example 1 of this application. Figure 10 Four; Fig.15 This is a schematic diagram of the steps provided in Example 1 of this application. Figure 10 five; Fig.16 This is a schematic diagram of the steps provided in Example 1 of this application. Figure 10 six; Fig.17 This is a schematic diagram of the steps provided in Example 1 of this application. Figure 10 seven; Fig.18 This is a schematic diagram of the steps provided in Example 1 of this application. Figure 10 eight; Fig.19 This is a schematic diagram of the steps provided in Example 1 of this application. Figure 10 Nine; Fig. 20 This is a schematic diagram of the steps provided in Example 1 of this application. Figure 2 ten; Fig.21 This is a schematic diagram of the steps provided in Example 2 of the present application; Fig. 22This is a schematic diagram of the steps provided in Example 3 of this application. Figure 1 ; Fig.23 This is a schematic diagram of the steps provided in Example 3 of this application. Figure 2 .

[0022] Explanation of symbols: 1. BAW resonator carrier; 11. first resonant cavity; 12. first substrate; 13. first bonding layer; 2. first electrode layer; 3. piezoelectric layer; 4. second electrode layer; 5. BAW resonator cover; 51. second resonant cavity; 52. heat dissipation layer; 53. second substrate; 54. second bonding layer; 55. solder pad; 6. package connecting line; A. first direction; B. second direction. DETAILED DESCRIPTION

[0023] In order to make the purpose, technical solutions and advantages of this application clearer, the technical solutions in this application will be clearly and completely described below in conjunction with the drawings in this application. Obviously, the described embodiments are part of the embodiments of this application, not all of them. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0024] The terms "first", "second", etc. in the specification and claims of this application and the above-mentioned drawings are used to distinguish similar objects, and are not necessarily used to describe a specific order or sequence. It should be understood that the terms used in this way can be interchanged where appropriate, so that the embodiments described herein can be implemented in an order other than that illustrated or described herein.

[0025] First, as Figure 1 to Figure 23 As shown, the present application provides a bulk acoustic wave resonator, comprising: A bulk acoustic wave resonator carrier 1; the bulk acoustic wave resonator carrier 1 has a first resonant cavity 11; In a first direction A, the piezoelectric layer 3 and the BAW resonator cover 5 are sequentially located on one side of the BAW resonator carrier 1, the first direction A is perpendicular to the plane where the BAW resonator carrier 1 is located, and points from the BAW resonator carrier 1 to the piezoelectric layer 3; the BAW resonator cover 5 has a second resonant cavity 51 and a heat dissipation layer 52; the heat dissipation layer 52 has at least one protrusion; a second electrode layer 4 located on a side of the piezoelectric layer 3 close to the BAW resonator cover 5, the second electrode layer 4 covering a first area of ​​a first surface of the piezoelectric layer 3, the first area being a surface of the piezoelectric layer 3 close to the BAW resonator cover 5; A first electrode layer 2 is located on a side of the piezoelectric layer 3 close to the BAW resonator carrier 1, wherein the first electrode layer 2 covers a second area of ​​a second surface of the piezoelectric layer 3, and the second area is a surface of the piezoelectric layer 3 close to the BAW resonator carrier 1; an orthographic projection of the second area on the BAW resonator carrier 1 at least partially overlaps with an orthographic projection of the first area on the BAW resonator carrier 1.

[0026] The BAW resonator provided by the present application includes a BAW resonator carrier having a first resonant cavity, a first electrode layer, a piezoelectric layer, a second electrode layer, and a BAW resonator cover having a second resonant cavity and a heat dissipation layer; the heat dissipation layer has at least one protrusion; the second electrode layer covers a first area of ​​the first surface of the piezoelectric layer, the first area being the surface of the piezoelectric layer close to the BAW resonator cover; the first electrode layer covers a second area of ​​the second surface of the piezoelectric layer, the second area being the surface of the piezoelectric layer close to the BAW resonator carrier; the orthographic projection of the second area on the BAW resonator carrier overlaps at least partially with the orthographic projection of the first area on the BAW resonator carrier. The present application can increase the heat dissipation area, improve the heat dissipation efficiency, avoid the resonant frequency drift of the BAW resonator, enhance the stability of the overall structure of the BAW resonator, avoid the distortion and deformation of the resonant structure of the BAW resonator, slow down the aging of the BAW resonator or damage caused by heating, and improve the reliability and service life of the thin film BAW resonator by arranging a heat dissipation layer with a special structure at an appropriate position.

[0027] Preferably, the BAW resonator carrier 1 comprises: A first substrate 12 located on a side of the piezoelectric layer 3 away from the BAW resonator cover 5; a first bonding layer 13 located on a side of the first substrate 12 close to the piezoelectric layer 3; the first bonding layer 13 has a first protrusion and a second protrusion; in the first direction A, the height of the first protrusion is greater than the height of the second protrusion; The first resonant cavity 11 is formed by the first bonding layer 13, the piezoelectric layer 3 and the first electrode layer 2; The cross section of the first resonant cavity 11 in the second direction B is L-shaped; the cross section of the second resonant cavity 51 in the first direction A is L-shaped.

[0028] Preferably, the BAW resonator cover 5 comprises: a second substrate 53 located on a side of the heat dissipation layer 52 close to the BAW resonator carrier 1; a first through hole and a second through hole penetrating the second substrate 53 in the first direction A; A second bonding layer 54 located on a side of the second substrate 53 close to the piezoelectric layer 3; The pad 55 is located on the second bonding layer 54 and close to the piezoelectric layer 3. Figure 9~Figure 11 are top views of three embodiments of etching pads 55, Fig.11 Pad 55 is shown connected to ground.

[0029] Preferably, if Fig.21 As shown, the entire surface of the heat dissipation layer 52 away from the BAW resonator carrier 1 is connected to the entire surface of the second substrate 53 close to the BAW resonator carrier 1; Fig.21 The top view of the heat dissipation layer 52 in the embodiment shown is as follows Fig.18 It can increase the heat dissipation area, improve the heat dissipation efficiency, avoid the drift of the resonance frequency of the BAW resonator, enhance the stability of the overall structure of the BAW resonator, avoid the distortion of the resonance structure of the BAW resonator, slow down the aging of the BAW resonator or the damage caused by heating, and improve the reliability and service life of the film BAW resonator.

[0030] Preferably, if Fig.19 , Fig. 20 and Fig. 22 As shown, at least a portion of the surface of the heat dissipation layer 52 on the side close to the BAW resonator carrier 1 is in contact with the surface of the second substrate 53 on the side away from the BAW resonator carrier 1, and the heat dissipation layer 52 covers at least a portion of the surface of the second substrate 53 on the side away from the BAW resonator carrier 1; Fig.19 , Fig. 20 The top view of the heat dissipation layer 52 in the embodiment shown is as follows Fig.18 As shown, Fig. 22 The top view of the heat dissipation layer 52 in the embodiment shown is as follows Fig.23 As shown. It can better improve the heat dissipation efficiency and enhance the performance, structural stability, reliability and service life of the BAW resonator.

[0031] Preferably, if Fig.19 and Fig. 20 As shown, the heat dissipation layer 52 covers the entire surface of the second substrate 53 away from the BAW resonator carrier 1. It can further increase the heat dissipation area, improve the heat dissipation efficiency, avoid the drift of the resonance frequency of the BAW resonator, enhance the stability of the overall structure of the BAW resonator, avoid the distortion of the resonance structure of the BAW resonator, slow down the aging of the BAW resonator or the damage caused by heat, and improve the reliability and service life of the thin film BAW resonator.

[0032] Preferably, along the second direction B, the heat dissipation layer 52 has a third protrusion and a fourth protrusion of the same height, the surface of the third protrusion and the fourth protrusion close to the piezoelectric layer 3 is connected to at least a part of the surface of the pad 55 away from the piezoelectric layer 3, and the second direction B is parallel to the first direction A, and points from the piezoelectric layer 3 to the BAW resonator carrier 1. It can further improve the heat dissipation efficiency, avoid the drift of the resonant frequency of the BAW resonator, enhance the stability of the overall structure of the BAW resonator, avoid the distortion of the resonant structure of the BAW resonator, slow down the aging of the BAW resonator or the damage caused by heat, and improve the reliability and service life of the thin film BAW resonator.

[0033] Preferably, if Figure 19 to Figure 22 As shown, at least a portion of the surface of the pad 55 close to the BAW resonator carrier 1 is connected to at least a portion of the first electrode layer 2; and / or, as shown Fig. 20 As shown, at least a portion of the surface of the pad 55 close to the BAW resonator carrier 1 is in contact with at least a portion of the second electrode layer 4 .

[0034] Preferably, there is a first distance D between the heat dissipation layer 52 and the pad 55, and the first distance is determined by the device design, and its value range is: 5μm<D<100μm. It can further improve the heat dissipation efficiency, avoid the drift of the resonant frequency of the BAW resonator, enhance the stability of the overall structure of the BAW resonator, avoid the distortion of the resonant structure of the BAW resonator, slow down the aging of the BAW resonator or damage caused by heat, and improve the reliability and service life of the thin film BAW resonator.

[0035] Preferably, the BAW resonator further comprises: a packaging connection line 6 arranged on a side of the first electrode layer 2 away from the piezoelectric layer 3 .

[0036] In a second aspect, the present application further provides a filter, comprising a BAW resonator as described in any one of the first aspects. By arranging a heat dissipation layer with a special structure at an appropriate position, it is possible to increase the heat dissipation area, improve the heat dissipation efficiency, avoid the resonant frequency of the BAW resonator from drifting, enhance the stability of the overall structure of the BAW resonator, avoid the distortion of the resonant structure of the BAW resonator, slow down the aging of the BAW resonator or damage caused by heat, and improve the reliability and service life of the thin film BAW resonator.

[0037] Thirdly, Figure 1 to Figure 23 As shown, the present application also provides a method for manufacturing a bulk acoustic wave resonator, the manufacturing method is used to manufacture the bulk acoustic wave resonator described in any one of the first aspects above, the manufacturing method comprising: like Figure 1As shown, a carrier substrate 7 is provided; a second electrode layer 4 is formed on one side of the carrier substrate 7; a piezoelectric layer 3 is formed on a side of the second electrode layer 4 away from the carrier substrate 7; and a first electrode layer 2 is formed on a side of the piezoelectric layer 3 away from the carrier substrate 7; like Figure 2 As shown, the first electrode layer 2 is etched so that the first electrode layer 2 covers a second area of ​​the second surface of the piezoelectric layer 3, and the second area is at least a portion of the surface of the piezoelectric layer 3 close to the first electrode layer 2; like Figure 3 As shown, a first sacrificial layer 15 is formed on the side of the piezoelectric layer 3 and the first electrode layer 2 away from the carrier substrate 7; and the first sacrificial layer 15 is etched; like Figure 4 As shown, a first bonding layer 13 is formed on the side of the first sacrificial layer 15 away from the carrier substrate 7; like Figure 5 As shown, a first substrate 12 is formed on the side of the first bonding layer 13 away from the carrier substrate 7; like Figure 6 As shown, the BAW resonator is flipped 180° in the thickness direction, and the carrier substrate 7 is removed; like Figure 7 As shown, the second electrode layer 4 is etched so that the second electrode layer 4 covers a first area of ​​the first surface of the piezoelectric layer 3, and the first area is at least a portion of the surface of the piezoelectric layer 3 on a side close to the second electrode layer 4; the orthographic projection of the first area on the BAW resonator carrier 1 and the orthographic projection of the second area on the BAW resonator carrier 1 at least partially overlap; like Figure 8 As shown, the piezoelectric layer 3 is etched; like Figure 9~Figure 11 As shown, the pad 55 is etched, Figure 9~Figure 11 are top views of three embodiments of etching pads 55, Fig.11 The pad 55 shown is grounded; like Fig.12 As shown, the pad 55 is placed on the side of the piezoelectric layer 3 and the first electrode layer 2 close to the second electrode layer 4; like Fig.13 As shown, the first sacrificial layer 15 is removed to form the first resonant cavity 11; like Fig.14 As shown, a patterned second bonding layer 54 is formed; like Fig.15As shown, the second bonding layer 54 is placed on the side of the pad 55, the piezoelectric layer 3 and the first electrode layer 2 close to the second electrode layer 4 to form a second resonant cavity 51; and a second substrate 53 is formed on the side of the second bonding layer 54 away from the piezoelectric layer 3; like Fig.16 As shown, the second bonding layer 54 and the second substrate 53 are etched; like Figure 17 to Figure 23 As shown, the heat dissipation layer 52 is formed on the side of the pad 55 away from the piezoelectric layer 3. The heat dissipation layer 52 is electroplated on the entire surface. The surface thickness of the electroplating is greater than 0.5 μm, and the material used includes at least one of gold, silver, copper, and nickel.

[0038] like Figure 19 to Figure 22 As shown, a packaging connection line 6 is formed on a side of the first electrode layer 2 away from the piezoelectric layer 3 .

[0039] Preferably, if Fig.19 , Fig. 20 and Fig. 22 As shown, the heat dissipation layer 52 covers at least a portion of the surface of the second substrate 53 away from the piezoelectric layer 3; Fig. 22 The top view of the heat dissipation layer 52 in the embodiment shown is as follows Fig.23 As shown, the size of the opening at the center of the heat dissipation layer 52 is greater than 5 μm; and / or, if Fig.19 and Fig. 20 As shown, the heat dissipation layer 52 covers the entire surface of the second substrate 53 away from the piezoelectric layer 3; Fig.19 and Fig. 20 The top view of the heat dissipation layer 52 in the embodiment shown is as follows Fig.18 As shown; and / or, if Fig.21 As shown, the entire surface of the heat dissipation layer 52 away from the piezoelectric layer 3 is connected to the entire surface of the second substrate 53 close to the piezoelectric layer 3; Fig.21 The top view of the heat dissipation layer 52 in the embodiment shown is as follows Fig.18 shown.

[0040] By arranging a heat dissipation layer with a special structure at an appropriate position, the heat dissipation area can be increased, the heat dissipation efficiency can be improved, the resonant frequency of the BAW resonator can be prevented from drifting, the stability of the overall structure of the BAW resonator can be enhanced, the resonant structure of the BAW resonator can be prevented from twisting and deforming, the aging of the BAW resonator or damage caused by heat can be slowed down, and the reliability and service life of the thin film BAW resonator can be improved.

[0041] The above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present application.

Claims

1. A bulk acoustic wave resonator, characterized in that: include: A bulk acoustic wave resonator carrier (1); the bulk acoustic wave resonator carrier (1) has a first resonant cavity (11); In a first direction (A), a piezoelectric layer (3) and a BAW resonator cover (5) are sequentially located on one side of the BAW resonator carrier (1), the first direction (A) being perpendicular to the plane where the BAW resonator carrier (1) is located and pointing from the BAW resonator carrier (1) to the piezoelectric layer (3); the BAW resonator cover (5) has a second resonant cavity (51) and a heat dissipation layer (52); the heat dissipation layer (52) has at least one protrusion; a second electrode layer (4) located on a side of the piezoelectric layer (3) close to the BAW resonator cover (5), the second electrode layer (4) covering a first area of ​​a first surface of the piezoelectric layer (3), the first area being a surface of the piezoelectric layer (3) close to the BAW resonator cover (5); a first electrode layer (2) located on a side of the piezoelectric layer (3) close to the BAW resonator carrier (1), the first electrode layer (2) covering a second area of ​​a second surface of the piezoelectric layer (3), the second area being a surface of the piezoelectric layer (3) close to the BAW resonator carrier (1); The orthographic projection of the second region on the BAW resonator carrier (1) at least partially overlaps with the orthographic projection of the first region on the BAW resonator carrier (1).

2. The bulk acoustic wave resonator according to claim 1, characterized in that The bulk acoustic wave resonator carrier (1) comprises: A first substrate (12) located on a side of the piezoelectric layer (3) away from the BAW resonator cover (5); a first bonding layer (13) located on a side of the first substrate (12) close to the piezoelectric layer (3); the first bonding layer (13) has a first protrusion and a second protrusion; in the first direction (A), the height of the first protrusion is greater than the height of the second protrusion; The first resonant cavity (11) is formed by enclosing the first bonding layer (13), the piezoelectric layer (3) and the first electrode layer (2); The cross-section of the first resonant cavity (11) in the second direction (B) is L-shaped; and the cross-section of the second resonant cavity (51) in the first direction (A) is L-shaped.

3. The bulk acoustic wave resonator according to claim 1, characterized in that: The BAW resonator cover (5) comprises: a second substrate (53) located on a side of the heat dissipation layer (52) close to the bulk acoustic wave resonator carrier (1); a first through hole and a second through hole penetrating the second substrate (53) in the first direction (A); a second bonding layer (54) located on a side of the second substrate (53) close to the piezoelectric layer (3); A pad (55) located on a side of the second bonding layer (54) close to the piezoelectric layer (3).

4. The bulk acoustic wave resonator according to claim 3, characterized in that: The entire surface of the heat dissipation layer (52) on a side away from the BAW resonator carrier (1) is connected to the entire surface of the second substrate (53) on a side close to the BAW resonator carrier (1).

5. The bulk acoustic wave resonator according to claim 3, characterized in that: At least a portion of the surface of the heat dissipation layer (52) on a side close to the BAW resonator carrier (1) is in contact with a surface of the second substrate (53) on a side away from the BAW resonator carrier (1); and the heat dissipation layer (52) covers at least a portion of the surface of the second substrate (53) on a side away from the BAW resonator carrier (1).

6. The bulk acoustic wave resonator according to claim 4, characterized in that The heat dissipation layer (52) covers the entire surface of the second substrate (53) on a side away from the BAW resonator carrier (1).

7. The BAW resonator according to claim 3, characterized in that: Along a second direction (B), the heat dissipation layer (52) has a third protrusion and a fourth protrusion of the same height, the surfaces of the third protrusion and the fourth protrusion close to the piezoelectric layer (3) are connected to at least a portion of the surface of the pad (55) away from the piezoelectric layer (3), and the second direction (B) is parallel to the first direction (A) and points from the piezoelectric layer (3) to the bulk acoustic wave resonator carrier (1).

8. The bulk acoustic wave resonator according to claim 3, characterized in that: At least a portion of the surface of the solder pad (55) on a side close to the BAW resonator carrier (1) is in contact with at least a portion of the first electrode layer (2); and / or at least a portion of the surface of the solder pad (55) on a side close to the BAW resonator carrier (1) is in contact with at least a portion of the second electrode layer (4).

9. The BAW resonator according to claim 3, characterized in that: There is a first distance D between the heat dissipation layer (52) and the solder pad (55), and the first distance D is greater than 5 μm.

10. The bulk acoustic wave resonator according to claim 1, characterized in that Also includes: A packaging connection line (6) arranged on a side of the first electrode layer (2) away from the piezoelectric layer (3).

11. A filter, characterized in that: The bulk acoustic wave resonator comprises the bulk acoustic wave resonator according to any one of claims 1 to 10.

12. A method for manufacturing a bulk acoustic wave resonator, the method being used to manufacture the bulk acoustic wave resonator according to any one of claims 1 to 10, characterized in that: include: Providing a carrier substrate (7); forming a second electrode layer (4) on one side of the carrier substrate (7); forming a piezoelectric layer (3) on a side of the second electrode layer (4) away from the carrier substrate (7); and forming a first electrode layer (2) on a side of the piezoelectric layer (3) away from the carrier substrate (7); Etching the first electrode layer (2) so that the first electrode layer (2) covers a second area of ​​the second surface of the piezoelectric layer (3), the second area being at least a portion of the surface of the piezoelectric layer (3) on a side close to the first electrode layer (2); forming a first sacrificial layer (15) on a side of the piezoelectric layer (3) and the first electrode layer (2) away from the carrier substrate (7); and etching the first sacrificial layer (15); forming a first bonding layer (13) on a side of the first sacrificial layer (15) away from the carrier substrate (7); forming a first substrate (12) on a side of the first bonding layer (13) away from the carrier substrate (7); In the thickness direction, the BAW resonator is flipped 180° and the carrier substrate (7) is removed; The second electrode layer (4) is etched so that the second electrode layer (4) covers a first area of ​​a first surface of the piezoelectric layer (3), the first area being at least a portion of a surface of the piezoelectric layer (3) on a side close to the second electrode layer (4); and an orthographic projection of the first area on the BAW resonator carrier (1) and an orthographic projection of the second area on the BAW resonator carrier (1) at least partially overlap; Etching the piezoelectric layer (3); Etching pads (55); Placing the pad (55) on a side of the piezoelectric layer (3) and the first electrode layer (2) close to the second electrode layer (4); removing the first sacrificial layer (15) to form the first resonant cavity (11); forming a patterned second bonding layer (54); The second bonding layer (54) is placed on the side of the pad (55), the piezoelectric layer (3) and the first electrode layer (2) close to the second electrode layer (4) to form a second resonant cavity (51); and a second substrate (53) is formed on the side of the second bonding layer (54) away from the piezoelectric layer (3); Etching the second bonding layer (54) and the second substrate (53); forming the heat dissipation layer (52) on a side of the pad (55) away from the piezoelectric layer (3); A packaging connection line (6) is formed on a side of the first electrode layer (2) away from the piezoelectric layer (3).

13. The manufacturing method according to claim 12, characterized in that: The heat dissipation layer (52) covers at least a portion of the surface of the second substrate (53) on a side away from the piezoelectric layer (3); And / or, the heat dissipation layer (52) covers the entire surface of the second substrate (53) on a side away from the piezoelectric layer (3); And / or, the entire surface of the heat dissipation layer (52) on a side away from the piezoelectric layer (3) is in contact with the entire surface of the second substrate (53) on a side close to the piezoelectric layer (3).

Images