A bulk acoustic wave resonator, a filter and a manufacturing method thereof

Abstract

The present application provides a bulk acoustic wave resonator, a filter and a manufacturing method thereof. The bulk acoustic wave resonator includes a bulk acoustic wave resonator carrier having a first resonance cavity, a first electrode layer, a piezoelectric layer, a second electrode layer, and a bulk acoustic wave resonator cover having a second resonance cavity and a heat dissipation layer. The heat dissipation layer has at least one protrusion. The second electrode layer covers a first region of a first surface of the piezoelectric layer, and the first region is the surface of the piezoelectric layer close to the bulk acoustic wave resonator cover. The first electrode layer covers a second region of a second surface of the piezoelectric layer, and the second region is the surface of the piezoelectric layer close to the bulk acoustic wave resonator carrier. At least a part of the orthographic projection of the second region on the bulk acoustic wave resonator carrier overlaps with the orthographic projection of the first region on the bulk acoustic wave resonator carrier. By arranging a heat dissipation layer with a special structure at an appropriate position, the present application can increase the heat dissipation area and improve the heat dissipation efficiency, and solve the problems of poor heat dissipation effect and poor performance of the bulk acoustic wave resonator.

Description

Technical Field

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

[0002] Currently, with the rapid development of wireless communication, there are more and more devices for receiving and transmitting information in higher frequency bands, the requirements for radio frequency front-end circuits are becoming more and more stringent, and the market demand for high-performance filters is increasing. Due to its characteristics such as high quality factor, good out-of-band rejection, and high rectangularity coefficient, bulk acoustic wave filters are gradually becoming the mainstream in the market.

[0003] During the operation of a bulk acoustic wave resonator, heat is generated. Among them, the heat in the resonance region can be transferred outwards through the upper electrode and the lower electrode, while the heat in the non-resonance region can only be transferred outwards through the piezoelectric layer. Since the piezoelectric layer is currently mainly made of materials with poor thermal conductivity such as AlN, the existing bulk acoustic wave resonators cannot achieve efficient heat dissipation.

[0004] Therefore, on the premise of ensuring good performance of the bulk acoustic wave 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 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, including:

[0007] A bulk acoustic wave resonator carrier; the bulk acoustic wave resonator carrier has a first resonance cavity;

[0008] In a first direction A, a piezoelectric layer and a bulk acoustic wave resonator cover body are sequentially located on one side of the bulk acoustic wave resonator carrier. The first direction A is perpendicular to the plane where the bulk acoustic wave resonator carrier is located and points from the bulk acoustic wave resonator carrier to the piezoelectric layer; the bulk acoustic wave resonator cover body has a second resonance cavity and a heat dissipation layer; the heat dissipation layer has at least one protrusion;

[0009] A second electrode layer located on the side of the piezoelectric layer close to the bulk acoustic wave resonator cover body. The second electrode layer covers a first region of the first surface of the piezoelectric layer, and the first region is the surface of the piezoelectric layer on the side close to the bulk acoustic wave resonator cover body;

[0010] A first electrode layer located on a side of the piezoelectric layer close to the carrier of the bulk acoustic wave resonator, the first electrode layer covering a second region of a second surface of the piezoelectric layer, the second region being a surface of the piezoelectric layer on a side close to the carrier of the bulk acoustic wave resonator; a positive projection of the second region on the carrier of the bulk acoustic wave resonator and a positive projection of the first region on the carrier of the bulk acoustic wave resonator at least partially overlap.

[0011] Preferably, the carrier of the bulk acoustic wave resonator includes:

[0012] A first substrate located on a side of the piezoelectric layer away from the cover of the bulk acoustic wave resonator;

[0013] 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;

[0014] The first resonant cavity formed by enclosing the first bonding layer, the piezoelectric layer and the first electrode layer;

[0015] A cross-section of the first resonant cavity in a second direction B is L-shaped; a cross-section of the second resonant cavity in the first direction A is L-shaped.

[0016] Preferably, the cover of the bulk acoustic wave resonator includes:

[0017] A second substrate located on a side of the heat dissipation layer close to the carrier of the bulk acoustic wave resonator; a first through hole and a second through hole penetrating the second substrate in the first direction A;

[0018] A second bonding layer located on a side of the second substrate close to the piezoelectric layer;

[0019] A pad located on a side of the second bonding layer close to the piezoelectric layer.

[0020] Preferably, all surfaces on a side of the heat dissipation layer away from the carrier of the bulk acoustic wave resonator are in contact with all surfaces on a side of the second substrate close to the carrier of the bulk acoustic wave resonator.

[0021] Preferably, at least a part of a surface on a side of the heat dissipation layer close to the carrier of the bulk acoustic wave resonator is in contact with a surface on a side of the second substrate away from the carrier of the bulk acoustic wave resonator; the heat dissipation layer covers at least a part of a surface on a side of the second substrate away from the carrier of the bulk acoustic wave resonator.

[0022] Preferably, the heat dissipation layer covers all surfaces on a side of the second substrate away from the carrier of the bulk acoustic wave resonator.

[0023] Preferably, along the second direction B, the heat dissipation layer has a third protrusion and a fourth protrusion with the same height. The surfaces of the third protrusion and the fourth protrusion close to the piezoelectric layer are in contact with at least a part of the surface of the pad away from the piezoelectric layer. The second direction B is parallel to the first direction A and points from the piezoelectric layer to the bulk acoustic wave resonator carrier.

[0024] Preferably, at least a part of the surface of the pad close to the bulk acoustic wave resonator carrier is in contact with at least a part of the first electrode layer; and / or, at least a part of the surface of the pad close to the bulk acoustic wave resonator carrier is in contact with at least a part of the second electrode layer.

[0025] Preferably, there is a first distance D between the heat dissipation layer and the pad, and the first distance D > 5 μm.

[0026] Preferably, the bulk acoustic wave resonator further includes: a package connection line disposed on the side of the first electrode layer away from the piezoelectric layer.

[0027] In a second aspect, the present application further provides a filter, including the bulk acoustic wave resonator according to any one of the first aspects.

[0028] In a third aspect, the present application further provides a manufacturing method of a bulk acoustic wave resonator. The manufacturing method is used to manufacture the bulk acoustic wave resonator according to any one of the first aspects, and the manufacturing method includes:

[0029] providing a carrier substrate; forming a second electrode layer on one side of the carrier substrate; forming a piezoelectric layer on the side of the second electrode layer away from the carrier substrate; forming a first electrode layer on the side of the piezoelectric layer away from the carrier substrate;

[0030] etching the first electrode layer so that the first electrode layer covers a second region of the second surface of the piezoelectric layer, and the second region is at least a part of the surface of the piezoelectric layer close to the first electrode layer;

[0031] forming a first sacrificial layer on the side of the piezoelectric layer and the first electrode layer away from the carrier substrate;

[0032] etching the first sacrificial layer;

[0033] forming a first bonding layer on the side of the first sacrificial layer away from the carrier substrate;

[0034] forming a first substrate on the side of the first bonding layer away from the carrier substrate;

[0035] in the thickness direction, flipping the bulk acoustic wave resonator by 180° and removing the carrier substrate;

[0036] Etch the second electrode layer such that the second electrode layer covers a first region of a first surface of the piezoelectric layer, where the first region is at least a part of the surface of the piezoelectric layer on a side close to the second electrode layer; at least a part of a positive projection of the first region on the bulk acoustic wave resonator carrier overlaps with a positive projection of the second region on the bulk acoustic wave resonator carrier;

[0037] Etch the piezoelectric layer;

[0038] Etch the pad;

[0039] Place the pad on a side of the piezoelectric layer and the first electrode layer close to the second electrode layer;

[0040] Remove the first sacrificial layer to form the first resonant cavity;

[0041] Form a patterned second bonding layer;

[0042] Place the second bonding layer on a side of the pad, the piezoelectric layer, and the first electrode layer close to the second electrode layer to form a second resonant cavity; form a second substrate on a side of the second bonding layer away from the piezoelectric layer;

[0043] Etch the second bonding layer and the second substrate;

[0044] Form the heat dissipation layer on a side of the pad away from the piezoelectric layer;

[0045] Form a package connection line on a side of the first electrode layer away from the piezoelectric layer.

[0046] Preferably, the heat dissipation layer covers at least a part of a surface of the second substrate on a side away from the piezoelectric layer;

[0047] And / or, the heat dissipation layer covers all of the surface of the second substrate on a side away from the piezoelectric layer;

[0048] And / or, all of the surface of the heat dissipation layer on a side away from the piezoelectric layer is in contact with all of the surface of the second substrate on a side close to the piezoelectric layer.

[0049] The bulk acoustic wave resonator provided by the present application includes a bulk acoustic wave resonator carrier having a first resonant cavity, a first electrode layer, a piezoelectric layer, a second electrode layer, and a bulk acoustic wave resonator cover body 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 region of the first surface of the piezoelectric layer, and the first region is the surface of the piezoelectric layer close to the bulk acoustic wave resonator cover body; the first electrode layer covers a second region of the second surface of the piezoelectric layer, and the second region is the surface of the piezoelectric layer close to the bulk acoustic wave resonator carrier; at least a part of the orthographic projection of the second region on the bulk acoustic wave resonator carrier overlaps with the orthographic projection of the first region on the bulk acoustic wave resonator carrier. By arranging a heat dissipation layer with a special structure at an appropriate position, the present application can increase the heat dissipation area, improve the heat dissipation efficiency, avoid the resonance frequency of the bulk acoustic wave resonator from drifting, enhance the stability of the overall structure of the bulk acoustic wave resonator, avoid the resonance structure of the bulk acoustic wave resonator from being distorted and deformed, slow down the aging of the bulk acoustic wave resonator or the damage caused by heating, and improve the reliability and service life of the thin film bulk acoustic wave resonator. BRIEF DESCRIPTION OF THE DRAWINGS

[0050] In order to more clearly illustrate the technical solutions in the present application or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the drawings in the following description are some embodiments of the present application. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0051] Figure 1 It is a schematic diagram of the steps provided in the first embodiment of the present application Figure 1 ;

[0052] Figure 2 It is a schematic diagram of the steps provided in the first embodiment of the present application Figure 2 ;

[0053] Figure 3 It is a schematic diagram of the steps provided in the first embodiment of the present application Figure 3 ;

[0054] Figure 4 It is a schematic diagram of the steps provided in the first embodiment of the present application Figure 4 ;

[0055] Figure 5 It is a schematic diagram of the steps provided in the first embodiment of the present application Figure 5 ;

[0056] Figure 6 It is a schematic diagram of the steps provided in the first embodiment of the present application Figure 6 ;

[0057] Figure 7 It is a schematic diagram of the steps provided in the first embodiment of the present application Figure 7 ;

[0058] Figure 8 It is a step diagram provided by the first embodiment of the present application Figure 8 ;

[0059] Figure 9 It is a step diagram provided by the first embodiment of the present application Figure 9 ;

[0060] Figure 10 It is a step diagram provided by the first embodiment of the present application Figure 10 ;

[0061] Figure 11 It is a step diagram provided by the first embodiment of the present application Figure 11 One;

[0062] Figure 12 It is a step diagram provided by the first embodiment of the present application Figure 12 Two;

[0063] Figure 13 It is a step diagram provided by the first embodiment of the present application Figure 13 Three;

[0064] Figure 14 It is a step diagram provided by the first embodiment of the present application Figure 14 Four;

[0065] Figure 15 It is a step diagram provided by the first embodiment of the present application Figure 15 Five;

[0066] Figure 16 It is a step diagram provided by the first embodiment of the present application Figure 16 Six;

[0067] Figure 17 It is a step diagram provided by the first embodiment of the present application Figure 17 Seven;

[0068] Figure 18 It is a step diagram provided by the first embodiment of the present application Figure 18 Eight;

[0069] Figure 19 It is a step diagram provided by the first embodiment of the present application Figure 19 Nine;

[0070] Figure 20 It is a step diagram provided by the first embodiment of the present application Figure 2 Ten;

[0071] Figure 21 It is a step diagram provided by the second embodiment of the present application;

[0072] Figure 22It is a step diagram provided in Embodiment 3 of the present application Figure 1 ;

[0073] Figure 23 It is a step diagram provided in Embodiment 3 of the present application Figure 2 。

[0074] Symbol description:

[0075] 1. Bulk acoustic wave resonator carrier; 11. First resonance cavity; 12. First substrate; 13. First bonding layer; 2. First electrode layer; 3. Piezoelectric layer; 4. Second electrode layer; 5. Bulk acoustic wave resonator cover; 51. Second resonance cavity; 52. Heat dissipation layer; 53. Second substrate; 54. Second bonding layer; 55. Pad; 6. Package connection line; A. First direction; B. Second direction. Detailed implementation manners

[0076] To make the objectives, technical solutions, and advantages of the present application clearer, the technical solutions in the present application will be clearly and completely described below with reference to the accompanying drawings in the present application. Apparently, the described embodiments are some, but not all, of the embodiments of the present application. All other embodiments obtained by those of ordinary skill in the art based on the embodiments in the present application without making creative efforts belong to the scope of protection of the present application.

[0077] The terms "first", "second", etc. in the specification and claims of the present application and the above-mentioned accompanying drawings are used to distinguish similar objects and do not necessarily need to describe a specific order or sequence. It should be understood that such data can be interchanged under appropriate circumstances so that the embodiments described here can be implemented in an order different from that shown or described here.

[0078] In a first aspect, as Figures 1 to 23 shown, the present application provides a bulk acoustic wave resonator, including:

[0079] A bulk acoustic wave resonator carrier 1; the bulk acoustic wave resonator carrier 1 has a first resonance cavity 11;

[0080] In the first direction A, a piezoelectric layer 3 and a bulk acoustic wave resonator cover 5 are sequentially located on one side of the bulk acoustic wave resonator carrier 1. The first direction A is perpendicular to the plane where the bulk acoustic wave resonator carrier 1 is located and points from the bulk acoustic wave resonator carrier 1 to the piezoelectric layer 3; the bulk acoustic wave resonator cover 5 has a second resonance cavity 51 and a heat dissipation layer 52; the heat dissipation layer 52 has at least one protrusion;

[0081] A second electrode layer 4 located on one side of the piezoelectric layer 3 close to the bulk acoustic wave resonator cover 5, the second electrode layer 4 covering a first region of the first surface of the piezoelectric layer 3, the first region being the surface of the piezoelectric layer 3 on the side close to the bulk acoustic wave resonator cover 5;

[0082] A first electrode layer 2 located on one side of the piezoelectric layer 3 close to the bulk acoustic wave resonator carrier 1, the first electrode layer 2 covering a second region of the second surface of the piezoelectric layer 3, the second region being the surface of the piezoelectric layer 3 on the side close to the bulk acoustic wave resonator carrier 1; at least a part of the orthographic projection of the second region on the bulk acoustic wave resonator carrier 1 overlaps with the orthographic projection of the first region on the bulk acoustic wave resonator carrier 1.

[0083] The bulk acoustic wave resonator provided in this application includes a bulk acoustic wave resonator carrier having a first resonant cavity, a first electrode layer, a piezoelectric layer, a second electrode layer, and a bulk acoustic wave 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 region of the first surface of the piezoelectric layer, the first region being the surface of the piezoelectric layer on the side close to the bulk acoustic wave resonator cover; the first electrode layer covers a second region of the second surface of the piezoelectric layer, the second region being the surface of the piezoelectric layer on the side close to the bulk acoustic wave resonator carrier; at least a part of the orthographic projection of the second region on the bulk acoustic wave resonator carrier overlaps with the orthographic projection of the first region on the bulk acoustic wave resonator carrier. By providing a heat dissipation layer with a special structure at an appropriate position in this application, the heat dissipation area can be increased, the heat dissipation efficiency can be improved, the resonant frequency drift of the bulk acoustic wave resonator can be avoided, the stability of the overall structure of the bulk acoustic wave resonator can be enhanced, the resonant structure distortion of the bulk acoustic wave resonator can be avoided, the aging of the bulk acoustic wave resonator or the damage caused by heating can be slowed down, and the reliability and service life of the thin film bulk acoustic wave resonator can be improved.

[0084] Preferably, the bulk acoustic wave resonator carrier 1 includes:

[0085] A first substrate 12 located on one side of the piezoelectric layer 3 away from the bulk acoustic wave resonator cover 5;

[0086] A first bonding layer 13 located on one 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;

[0087] The first resonant cavity 11 formed by enclosing the first bonding layer 13, the piezoelectric layer 3 and the first electrode layer 2;

[0088] 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.

[0089] Preferably, the bulk acoustic wave resonator cover 5 includes:

[0090] A second substrate 53 located on the 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 through the second substrate 53 in the first direction A;

[0091] A second bonding layer 54 located on the side of the second substrate 53 close to the piezoelectric layer 3;

[0092] A pad 55 located on the side of the second bonding layer 54 close to the piezoelectric layer 3, Figures 9 to 11 is a top view of three embodiments of etching the pad 55, Figure 11 The shown pad 55 is grounded.

[0093] Preferably, as Figure 21 shown, all surfaces of the side of the heat dissipation layer 52 away from the bulk acoustic wave resonator carrier 1 are in contact with all surfaces of the side of the second substrate 53 close to the bulk acoustic wave resonator carrier 1; Figure 21 The top view of the heat dissipation layer 52 in the shown embodiment is as Figure 18 shown. It can increase the heat dissipation area, improve the heat dissipation efficiency, avoid the resonance frequency of the bulk acoustic wave resonator from drifting, enhance the stability of the overall structure of the bulk acoustic wave resonator, avoid the resonance structure of the bulk acoustic wave resonator from being distorted and deformed, slow down the aging of the bulk acoustic wave resonator or damage caused by heat, and improve the reliability and service life of the thin film bulk acoustic wave resonator.

[0094] Preferably, as Figure 19 , Figure 20 and Figure 22 shown, at least a part of the surface of the heat dissipation layer 52 close to the bulk acoustic wave resonator carrier 1 is in contact with the surface of the second substrate 53 away from the bulk acoustic wave resonator carrier 1, and the heat dissipation layer 52 covers at least a part of the surface of the second substrate 53 away from the bulk acoustic wave resonator carrier 1; Figure 19 , Figure 20 shown, the top view of the heat dissipation layer 52 in the embodiment is as Figure 18 shown, Figure 22 shown, the top view of the heat dissipation layer 52 in the embodiment is as Figure 23 shown. It can better improve the heat dissipation efficiency, enhance the performance, structural stability, reliability and service life of the bulk acoustic wave resonator.

[0095] Preferably, as Figure 19 and Figure 20As shown, the heat dissipation layer 52 covers the entire surface of the second substrate 53 on the side away from the bulk acoustic wave resonator carrier 1. This can further increase the heat dissipation area, improve the heat dissipation efficiency, prevent the resonance frequency of the bulk acoustic wave resonator from drifting, enhance the stability of the overall structure of the bulk acoustic wave resonator, prevent the resonance structure of the bulk acoustic wave resonator from being distorted or deformed, slow down the aging of the bulk acoustic wave resonator or damage caused by heat, and improve the reliability and service life of the thin film bulk acoustic wave resonator.

[0096] Preferably, along the second direction B, the heat dissipation layer 52 has a third protrusion and a fourth protrusion with the same height. The surfaces of the third protrusion and the fourth protrusion on the side close to the piezoelectric layer 3 are in contact with at least a part of the surface of the pad 55 on the side away from the piezoelectric layer 3. 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. This can further improve the heat dissipation efficiency, prevent the resonance frequency of the bulk acoustic wave resonator from drifting, enhance the stability of the overall structure of the bulk acoustic wave resonator, prevent the resonance structure of the bulk acoustic wave resonator from being distorted or deformed, slow down the aging of the bulk acoustic wave resonator or damage caused by heat, and improve the reliability and service life of the thin film bulk acoustic wave resonator.

[0097] Preferably, as Figures 19 to 22 shown, at least a part of the surface of the pad 55 on the side close to the bulk acoustic wave resonator carrier 1 is in contact with at least a part of the first electrode layer 2; and / or, as Figure 20 shown, at least a part of the surface of the pad 55 on the side close to the bulk acoustic wave resonator carrier 1 is in contact with at least a part of the second electrode layer 4.

[0098] Preferably, there is a first distance D between the heat dissipation layer 52 and the pad 55. The first distance is determined by device design and its value range is: 5μm < D < 100μm. This can further improve the heat dissipation efficiency, prevent the resonance frequency of the bulk acoustic wave resonator from drifting, enhance the stability of the overall structure of the bulk acoustic wave resonator, prevent the resonance structure of the bulk acoustic wave resonator from being distorted or deformed, slow down the aging of the bulk acoustic wave resonator or damage caused by heat, and improve the reliability and service life of the thin film bulk acoustic wave resonator.

[0099] Preferably, the bulk acoustic wave resonator further includes: a packaging connection line 6 disposed on the side of the first electrode layer 2 away from the piezoelectric layer 3.

[0100] Second aspect, the present application also provides a filter, including the bulk acoustic wave resonator described in any one of the first aspect. By providing 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 resonance frequency drift of the bulk acoustic wave resonator can be avoided, the stability of the overall structure of the bulk acoustic wave resonator can be enhanced, the resonance structure distortion of the bulk acoustic wave resonator can be avoided, the aging of the bulk acoustic wave resonator or the damage caused by heat can be slowed down, and the reliability and service life of the thin film bulk acoustic wave resonator can be improved.

[0101] Third aspect, as Figures 1 to 23 shown, the present application also provides a manufacturing method of a bulk acoustic wave resonator, which is used to manufacture the bulk acoustic wave resonator described in any one of the first aspect, and the manufacturing method includes:

[0102] As Figure 1 shown, provide a carrier substrate 7; form a second electrode layer 4 on one side of the carrier substrate 7; form a piezoelectric layer 3 on the side of the second electrode layer 4 away from the carrier substrate 7; form a first electrode layer 2 on the side of the piezoelectric layer 3 away from the carrier substrate 7;

[0103] As Figure 2 shown, etch the first electrode layer 2 so that the first electrode layer 2 covers a second region of the second surface of the piezoelectric layer 3, and the second region is at least a part of the surface of the piezoelectric layer 3 on the side close to the first electrode layer 2;

[0104] As Figure 3 shown, form a first sacrificial layer 15 on the side of the piezoelectric layer 3 and the first electrode layer 2 away from the carrier substrate 7; etch the first sacrificial layer 15;

[0105] As Figure 4 shown, form a first bonding layer 13 on the side of the first sacrificial layer 15 away from the carrier substrate 7;

[0106] As Figure 5 shown, form a first substrate 12 on the side of the first bonding layer 13 away from the carrier substrate 7;

[0107] As Figure 6 shown, turn the bulk acoustic wave resonator 180° in the thickness direction and remove the carrier substrate 7;

[0108] As Figure 7As shown, etch the second electrode layer 4 such that the second electrode layer 4 covers a first region of the first surface of the piezoelectric layer 3, where the first region is at least a part of the surface of the piezoelectric layer 3 on the side close to the second electrode layer 4; at least a part of the orthographic projection of the first region on the bulk acoustic wave resonator carrier 1 overlaps with the orthographic projection of the second region on the bulk acoustic wave resonator carrier 1;

[0109] As Figure 8 shown, etch the piezoelectric layer 3;

[0110] As Figures 9 to 11 shown, etch the pad 55, Figures 9 to 11 which is a top view of three embodiments of etching the pad 55, Figure 11 the pad 55 shown is grounded;

[0111] As Figure 12 shown, place the pad 55 on the sides of the piezoelectric layer 3 and the first electrode layer 2 close to the second electrode layer 4;

[0112] As Figure 13 shown, remove the first sacrificial layer 15 to form the first resonator cavity 11;

[0113] As Figure 14 shown, form a patterned second bonding layer 54;

[0114] As Figure 15 shown, place the second bonding layer 54 on the sides 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 resonator cavity 51; form a second substrate 53 on the side of the second bonding layer 54 away from the piezoelectric layer 3;

[0115] As Figure 16 shown, etch the second bonding layer 54 and the second substrate 53;

[0116] As Figures 17 to 23 shown, form the heat dissipation layer 52 on the side of the pad 55 away from the piezoelectric layer 3. The heat dissipation layer 52 is electroplated on the whole surface, and the surface thickness of the electroplating is greater than 0.5 μm. The materials used include at least one of gold, silver, copper, and nickel.

[0117] As Figures 19 to 22 shown, form a package connection line 6 on the side of the first electrode layer 2 away from the piezoelectric layer 3.

[0118] Preferably, as Figure 19 , Figure 20 and Figure 22 shown, the heat dissipation layer 52 covers at least a part of the surface of the second substrate 53 on the side away from the piezoelectric layer 3; Figure 22In the embodiment shown, the top view of the heat dissipation layer 52 is as follows Figure 23 shown, the size of the opening at the center position of the heat dissipation layer 52 is greater than 5 μm;

[0119] and / or, as Figure 19 and Figure 20 shown, the heat dissipation layer 52 covers all the surfaces of the second substrate 53 on the side away from the piezoelectric layer 3; as Figure 19 and Figure 20 In the embodiment shown, the top view of the heat dissipation layer 52 is as follows Figure 18 shown;

[0120] and / or, as Figure 21 shown, all the surfaces of the heat dissipation layer 52 on the side away from the piezoelectric layer 3 are in contact with all the surfaces of the second substrate 53 on the side close to the piezoelectric layer 3; Figure 21 In the embodiment shown, the top view of the heat dissipation layer 52 is as follows Figure 18 shown.

[0121] 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 resonance frequency drift of the bulk acoustic wave resonator can be avoided, the stability of the overall structure of the bulk acoustic wave resonator can be enhanced, the resonance structure distortion of the bulk acoustic wave resonator can be avoided, the aging of the bulk acoustic wave resonator or the damage caused by heat can be slowed down, and the reliability and service life of the thin film bulk acoustic wave resonator can be improved.

[0122] The above embodiments are only used to illustrate the technical solutions of the present application, and are not intended to limit them; although the present application has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements for some of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate 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: BAW resonator carrier (1); The bulk acoustic wave resonator carrier (1) has a first resonant cavity (11); 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 a first direction (A), a height of the first protrusion is greater than a 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; the cross section of the second resonant cavity (51) in the first direction (A) is L-shaped; 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), wherein 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); and 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), the first electrode layer (2) covers 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); 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).

2. 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) is located on a side of the second bonding layer (54) close to the piezoelectric layer (3).

3. The bulk acoustic wave resonator according to claim 2, characterized in that: The entire surface of the heat dissipation layer (52) on a side away from the BAW resonator carrier (1) is in contact with the entire surface of the second substrate (53) on a side close to the BAW resonator carrier (1).

4. The bulk acoustic wave resonator according to claim 2, 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).

5. The bulk acoustic wave resonator according to claim 3, 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).

6. The bulk acoustic wave resonator according to claim 2, characterized in that: Along the 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 BAW resonator carrier (1).

7. The bulk acoustic wave resonator according to claim 2, 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).

8. The bulk acoustic wave resonator according to claim 2, characterized in that: There is a first distance D between the heat dissipation layer (52) and the pad (55), and the first distance D is greater than 5 μm.

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

10. A filter, characterized in that: The bulk acoustic wave resonator comprises the bulk acoustic wave resonator according to any one of claims 1 to 9.

11. 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 9, 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); 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 turned 180 degrees 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 a pad (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).

12. The manufacturing method according to claim 11, 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