Bulk acoustic wave resonator, manufacturing method thereof and electronic equipment

Abstract

The invention discloses a bulk acoustic wave resonator, a manufacturing method thereof and electronic equipment. The bulk acoustic wave resonator comprises a substrate; the substrate is provided with a first through hole penetrating through the thickness direction; the supporting layer is positioned on one side of the substrate; the supporting layer is provided with an air groove penetrating through the thickness direction, and the first through hole is communicated with the air groove; the resonance layer is located on the side, away from the substrate, of the supporting layer and covers the air groove, and the resonance layer is used for converting electric signals into bulk acoustic waves propagating in the thickness direction; the heat conduction structure is located on one side, close to the substrate, of the resonance layer; one end of the heat conduction structure is in contact with the resonance layer, and the other end of the heat conduction structure sequentially penetrates through the air groove and the first through hole.

Description

Technical Field

[0001] The present invention relates to the field of electronic technology, and in particular to a bulk acoustic wave resonator and a manufacturing method thereof, and electronic equipment. Background Art

[0002] With the rapid development of mobile communication technology, the application of many RF devices has increased significantly, among which the filter market will explode.

[0003] At present, the filtering devices used in personal mobile terminals (such as mobile phones) are mainly piezoelectric acoustic wave filters. The resonators that constitute this type of filter are mainly: Film Bulk Acoustic Resonator (FBAR), Solidly Mounted Resonator (SMR), Surface Acoustic Wave Resonator (SAW), among which FBAR and SMR are collectively referred to as bulk acoustic wave resonators.

[0004] However, when the BAW resonator is working, it will inevitably generate heat, which will bring significant negative effects, such as causing the resonator temperature to rise and cause the resonator frequency to drift, or accelerate the aging of the piezoelectric structure, or even directly cause it to be damaged, thereby affecting the reliability and life of the resonator, and at the same time limiting the further improvement of the resonator's power capacity.

[0005] In view of this, reducing the heat generated by the BAW resonator during operation has become a technical problem that needs to be solved urgently. Summary of the invention

[0006] The embodiments of the present invention provide a bulk acoustic wave resonator and a manufacturing method thereof, and an electronic device, so as to solve the technical problem in the prior art that the heat generated by the bulk acoustic wave resonator brings many negative effects.

[0007] In a first aspect, in order to solve the above technical problems, an embodiment of the present invention provides a bulk acoustic wave resonator, comprising:

[0008] A base substrate; the base substrate has a first through hole extending through the thickness direction;

[0009] A support layer is located on one side of the base substrate; the support layer has an air groove running through the thickness direction, and the first through hole is connected to the air groove;

[0010] A resonance layer, located on a side of the support layer away from the substrate and covering the air slot, the resonance layer being used to convert an electrical signal into a bulk acoustic wave propagating in a thickness direction;

[0011] The heat-conducting structure is located on a side of the resonance layer close to the base substrate; one end of the heat-conducting structure contacts the resonance layer, and the other end of the heat-conducting structure passes through the air groove and the first through hole in sequence.

[0012] In a possible implementation manner, the support layer includes:

[0013] At least one total reflection structure surrounds the air slot, and the total reflection structure is used to prevent the leakage of the transverse wave generated along with the body acoustic wave, and the propagation direction of the transverse wave is perpendicular to the thickness direction.

[0014] In a possible implementation manner, the total reflection structure includes:

[0015] A first structure and a second structure;

[0016] The first structure is located in the inner layer, the second structure is located in the outer layer, and the impedance of the first structure is lower than the impedance of the second structure.

[0017] In a possible implementation manner, the base substrate further includes a second through hole penetrating in the thickness direction;

[0018] The total reflection structure extends through the second through hole to a side of the substrate away from the resonance layer.

[0019] In a possible implementation manner, the heat-conducting structure includes:

[0020] a heat absorption structure, located on a side of the resonance layer close to the substrate, and in contact with at least a portion of the resonance layer and the air slot;

[0021] The heat dissipation structure is located on a side of the heat absorption structure close to the base substrate; one end of the heat dissipation structure is connected to the heat absorption structure, and the other end is located in the first through hole.

[0022] In a possible implementation manner, an orthographic projection area of ​​the heat absorption structure on the base substrate is larger than an orthographic projection area of ​​the heat dissipation structure on the base substrate.

[0023] In a possible implementation manner, the orthographic projection of the heat absorption structure on the base substrate is located within the orthographic projection of the air groove on the base substrate.

[0024] In a possible implementation manner, the heat absorption structure overlaps with the resonance layer.

[0025] In a possible implementation manner, the resonance layer includes:

[0026] A first electrode layer is located on a side of the support layer away from the substrate;

[0027] A piezoelectric layer is located on a side of the first electrode layer away from the substrate;

[0028] The second electrode layer is located at a side of the piezoelectric layer away from the substrate.

[0029] A possible implementation further includes:

[0030] The metal layer is located on a side of the second electrode layer away from the base substrate.

[0031] In a second aspect, an embodiment of the present invention provides a method for manufacturing a bulk acoustic wave resonator, comprising:

[0032] Providing a substrate;

[0033] A support layer is formed on one side of the base substrate; the support layer has an air groove running through the thickness direction;

[0034] filling a sacrificial layer in the air groove;

[0035] forming a blind hole penetrating the sacrificial layer to the interior of the substrate, and forming a heat conducting structure in the blind hole;

[0036] forming a resonance layer on a side of the heat-conducting structure away from the substrate, and removing the sacrificial layer;

[0037] The base substrate is thinned so that the blind hole becomes a first through hole penetrating the thinned base substrate.

[0038] A possible implementation manner is to form a blind hole penetrating through the sacrificial layer to the interior of the substrate, and to form a heat conducting structure in the blind hole, including:

[0039] forming a groove in the sacrificial layer;

[0040] Drilling a hole from the bottom of the groove into the substrate to obtain a sub-blind hole; the sub-blind hole penetrates the sacrificial layer and enters the interior of the substrate;

[0041] Filling the sub-blind holes with heat dissipation material to obtain a heat dissipation structure;

[0042] The groove is filled with a heat absorbing material to obtain a heat absorbing structure; the heat dissipation structure and the heat absorbing structure together constitute the heat conducting structure.

[0043] A possible implementation manner is to form a blind hole penetrating through the sacrificial layer to the interior of the substrate, and to form a heat conducting structure in the blind hole, including:

[0044] Drilling a hole from the sacrificial layer into the base substrate to obtain the blind hole;

[0045] Filling the blind hole with heat dissipation material to obtain a heat dissipation structure;

[0046] A heat absorbing structure is formed on a side of the heat dissipation structure away from the substrate; the heat absorbing structure overlaps with the resonance structure; and the heat dissipation structure and the heat absorbing structure together constitute the heat conducting structure.

[0047] In a third aspect, an embodiment of the present invention provides an electronic device, comprising the BAW resonator as described in the first aspect. BRIEF DESCRIPTION OF THE DRAWINGS

[0048] Figure 1 is a schematic diagram of the structure of a FBAR;

[0049] Figure 2 is a schematic diagram of the structure of an SMR;

[0050] Figure 3 A schematic structural diagram of a bulk acoustic wave resonator provided by an embodiment of the present invention;

[0051] Figure 4 A schematic structural diagram of a heat-conducting structure provided by an embodiment of the present invention;

[0052] Figure 5 A schematic structural diagram of another heat-conducting structure provided by an embodiment of the present invention;

[0053] Figure 6 A schematic structural diagram of another heat-conducting structure provided by an embodiment of the present invention;

[0054] Figure 7 A schematic structural diagram of another bulk acoustic wave resonator provided by an embodiment of the present invention;

[0055] Figure 8 A schematic structural diagram of a total reflection structure provided by an embodiment of the present invention;

[0056] Fig. 9 A schematic structural diagram of another bulk acoustic wave resonator provided by an embodiment of the present invention;

[0057] Fig.10 A schematic structural diagram of another bulk acoustic wave resonator provided by an embodiment of the present invention;

[0058] Fig.11 A schematic structural diagram of another bulk acoustic wave resonator provided by an embodiment of the present invention;

[0059] Fig.12 A schematic diagram of manufacturing a bulk acoustic wave resonator provided by an embodiment of the present invention;

[0060] Fig.13A schematic diagram of forming a heat-conducting structure provided by an embodiment of the present invention;

[0061] Fig.14 A schematic diagram of another method for forming a heat-conducting structure provided in an embodiment of the present invention.

[0062] Reference numerals:

[0063] A first substrate 01, a groove N, a first bottom electrode 02, a first piezoelectric layer 03, and a first top electrode 04;

[0064] A second substrate 01', a Bragg reflection layer 02', a high acoustic impedance layer 021', a low acoustic impedance layer 022', a second bottom electrode 03', a second piezoelectric layer 04', and a second top electrode 05';

[0065] Substrate 1, first through hole H1, support layer 2, air slot M, resonance layer 3, heat conduction structure 4, thickness direction Y, heat absorption structure 41, heat dissipation structure 42, first structure 211, second structure 212, second through hole H2, first electrode layer 31, piezoelectric layer 32, second electrode layer 33, metal layer 5;

[0066] Sacrificial layer 6, blind hole H, groove H', sub-blind hole H". DETAILED DESCRIPTION

[0067] The embodiments of the present invention provide a bulk acoustic wave resonator and a manufacturing method thereof, and an electronic device, so as to solve the technical problem in the prior art that the heat generated by the bulk acoustic wave resonator brings many negative effects.

[0068] It should be understood that the specific structural and functional details disclosed in the embodiments of the present invention are only representative and are for the purpose of describing the exemplary embodiments of the present application. However, the present application can be specifically implemented in many alternative forms or combinations, and should not be interpreted as being limited to the embodiments described herein.

[0069] In the description of the present application, it should be understood that the terms "center", "lateral", "up", "down", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, which are only for the convenience of describing the present application and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present application. In addition, the terms "first" and "second" are used for descriptive purposes only, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present application, unless otherwise specified, "multiple" means two or more. In addition, the term "including" and any variation thereof are intended to cover non-exclusive inclusions.

[0070] In the description of this application, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0071] The terms used in this application are only for describing specific embodiments and are not intended to limit exemplary embodiments. Unless the context clearly indicates otherwise, the singular forms "one", "one" and "item" used herein are also intended to include plural numbers. It should also be understood that the terms "include" and / or "comprise" used herein specify the existence of stated features, integers, steps, operations, units and / or components, without excluding the existence or addition of one or more other features, integers, steps, operations, units, components and / or combinations thereof.

[0072] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and understandable, the present invention will be further described below with reference to the accompanying drawings and examples. However, the exemplary embodiments can be implemented in various forms and should not be understood as being limited to the embodiments described herein; on the contrary, these embodiments are provided to make the present invention more comprehensive and complete, and to fully convey the concepts of the exemplary embodiments to those skilled in the art. The same figure marks in the figures represent the same or similar structures, and thus their repeated descriptions will be omitted. The words expressing position and direction described in the present invention are all explained using the accompanying drawings as examples, but changes can be made as needed, and the changes made are all included in the scope of protection of the present invention. The drawings of the present invention are only used to illustrate the relative position relationship and do not represent the true proportions.

[0073] It should be noted that specific details are described in the following description to facilitate a full understanding of the present invention. However, the present invention can be implemented in a variety of other ways different from those described herein, and those skilled in the art can make similar generalizations without violating the connotation of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below. The subsequent description of the specification is a preferred embodiment of the present application, but the description is for the purpose of illustrating the general principles of the present application and is not intended to limit the scope of the present application. The scope of protection of the present application shall be determined by the definition of the attached claims.

[0074] See also Figure 1 and Figure 2 , Figure 1 It is a structural diagram of a FBAR. Figure 2 A schematic diagram of the structure of an SMR.

[0075] like Figure 1 As shown, FBAR includes:

[0076] A first substrate 01, wherein one side of the first substrate 01 has a groove N;

[0077] The first bottom electrode 02 is located at the side of the groove N of the first substrate 01; the first bottom electrode 02 closes the opening of the groove N in the first substrate 01, thereby forming a cavity;

[0078] A first piezoelectric layer 03, located on a side of the first bottom electrode 02 away from the first substrate 01;

[0079] The first top electrode 04 is located on a side of the first piezoelectric layer 03 away from the first substrate 01 .

[0080] FBAR uses the acoustic impedance of air in the cavity to be approximately zero to achieve total reflection of interface acoustic waves. It has a high quality factor and is easy to integrate. However, since air is a poor conductor of heat, the heat generated by FBAR can easily cause the temperature of the device to rise, resulting in a shift in the resonant frequency and affecting the filtering performance. At the same time, the air cavity structure affects the mechanical robustness.

[0081] like Figure 2 As shown, SMR includes:

[0082] Second substrate 01';

[0083] A Bragg reflection layer 02' located on one side of the second substrate 01', wherein the Bragg reflection layer 02' comprises high acoustic impedance layers 021' and low acoustic impedance layers 022' stacked alternately;

[0084] The second bottom electrode 03' is located on a side of the high acoustic impedance layer 021' and the low acoustic impedance layer 022' away from the second substrate 01';

[0085] The second piezoelectric layer 04' is located on a side of the second bottom electrode 03' away from the second substrate 01';

[0086] The second top electrode 05 ′ is located on a side of the second piezoelectric layer 04 ′ away from the second substrate 01 ′.

[0087] SMR achieves total reflection based on a Bragg reflection layer 02' consisting of alternating high acoustic impedance layers 021' and low acoustic impedance layers 022'. The Bragg reflection layer 02' of this structure brings about a certain degree of sound wave leakage, so the quality factor is low, and the thickness of each film layer in the Bragg reflection layer 02' is required to be high, which increases the difficulty of preparation, but improves the mechanical firmness and heat dissipation performance.

[0088] However, when a BAW resonator is excited by a longitudinal wave (bulk acoustic wave), it will also generate a transverse wave, which will cause parasitic resonance and thus affect the performance of the SMR.

[0089] In order to solve the problems existing in the above-mentioned BAW resonator, the present invention provides a BAW resonator and a manufacturing method thereof, and an electronic device, which are described in detail below with reference to the accompanying drawings.

[0090] See also Figure 3 A schematic diagram of the structure of a bulk acoustic wave resonator provided in an embodiment of the present invention, the bulk acoustic wave resonator comprising:

[0091] The substrate 1 has a first through hole H1 extending in a thickness direction Y. The substrate 1 may be made of ceramic, glass, Si, GaAs or sapphire.

[0092] The support layer 2 is located on one side of the base substrate 1; the support layer 2 has an air groove M penetrating in the thickness direction Y, and the first through hole H1 is connected to the air groove M;

[0093] The resonance layer 3 is located on the side of the support layer 2 away from the substrate 1 and covers the air slot M. The resonance layer 3 is used to convert the electrical signal into a bulk acoustic wave propagating along the thickness direction Y. The substrate 1 and the resonance layer 3 respectively close the two openings of the air slot M in the support layer 2 to form a cavity, so that the bulk acoustic wave generated by the resonance layer 3 is totally reflected at the cavity interface.

[0094] The heat conducting structure 4 is located on a side of the resonance layer 3 close to the base substrate 1 ; one end of the heat conducting structure 4 contacts the resonance layer 3 , and the other end of the heat conducting structure 4 passes through the air slot M and the first through hole H1 in sequence.

[0095] In the embodiment provided by the present invention, by arranging a heat-conducting structure 4 on the side of the resonance layer 3 close to the base substrate 1, and making one end of the heat-conducting structure 4 contact with the resonance layer 3, and the other end passes through the air slot M and the first through hole H1 in sequence, the heat-conducting structure 4 can be used to conduct the heat in the resonance layer 3 and the cavity to the outside, reduce the heat generated by the bulk acoustic wave resonator during operation, and reduce the negative effects caused by the heat, and effectively support the resonance layer 3, thereby improving the structural strength of the cavity.

[0096] See also Figure 4 A schematic diagram of a heat-conducting structure 4 provided in an embodiment of the present invention. The heat-conducting structure 4 includes:

[0097] The heat absorption structure 41 is located on a side of the resonance layer 3 close to the substrate 1 and is in contact with at least a portion of the resonance layer 3 and the air slot M;

[0098] The heat dissipation structure 42 is located on a side of the heat absorption structure 41 close to the base substrate 1 ; one end of the heat dissipation structure 42 is connected to the heat absorption structure 41 , and the other end is located in the first through hole H1 .

[0099] The material used for the heat absorption structure 41 can be inorganic materials such as silicon dioxide, aluminum nitride, aluminum oxide, silicon nitride, beryllium oxide, polycrystalline diamond (PCD), single crystal silicon, polycrystalline silicon, germanium, and organic materials such as silicon-containing polymers and epoxy resins, or metal materials such as gold, or a composite of the above materials.

[0100] In some embodiments, the thickness of the heat dissipation structure 42 ranges from 8 to 13 um.

[0101] The material used for the heat dissipation structure 42 can be metal materials such as copper, gold, silver, aluminum, etc., non-metal materials such as diamond, high thermal conductivity silicon, etc., or a composite of the above materials.

[0102] By providing a heat absorption structure 41 at least partially in contact with the resonance layer 3 and the air slot M on the side of the resonance layer 3 close to the base substrate 1, the heat absorption structure 41 can be used to quickly absorb the heat in the resonance layer 3 and the air slot M; and on the side of the heat absorption structure 41 close to the base substrate 1, a heat dissipation structure 42 is provided, one end of which is connected to the heat absorption structure 41 and the other end is connected to the first through hole H1. The heat absorbed by the heat absorption structure 41 and the heat in the air slot M can be quickly transferred to the outside of the BAW sensor, thereby reducing the heat generated by the BAW resonator.

[0103] See also Figure 5A schematic diagram of another heat-conducting structure 4 provided in an embodiment of the present invention. The orthographic projection area of ​​the heat-absorbing structure 41 on the base substrate 1 is larger than the orthographic projection area of ​​the heat-dissipating structure 42 on the base substrate 1, so that the heat-absorbing structure 41 can absorb more heat from the resonance layer 3, which is beneficial to quickly reduce the heat generated by the BAW resonator during operation.

[0104] Please continue to see Figure 5 , the orthographic projection of the heat absorbing structure 41 on the base substrate 1 is located within the orthographic projection of the air slot M on the base substrate 1. By making the orthographic projection of the heat absorbing structure 41 on the base substrate 1 located within the orthographic projection of the air slot M on the base substrate 1, the heat absorbing structure 41 is accommodated in the air slot M and contacts the resonance layer 3, so that the heat absorbing structure 41 can absorb the heat in the resonance layer 3 and the air slot M, and conduct the heat to the outside of the BAW resonator through the heat dissipation structure 42 for heat dissipation.

[0105] See also Figure 6 A schematic structural diagram of another heat-conducting structure 4 provided in an embodiment of the present invention, in which a heat-absorbing structure 41 overlaps with the resonance layer 3, so that the contact area between the heat-absorbing structure 41 and the resonance layer 3 can be increased to the maximum extent, and the heat generated by the resonance layer 3 can be quickly conducted out of the BAW resonator by the heat-dissipating structure 42 through the heat-absorbing structure 41, thereby reducing the heat generated by the BAW resonator during operation and reducing the negative factors caused by the heat.

[0106] See also Figure 7 A schematic diagram of the structure of another BAW resonator provided by an embodiment of the present invention, wherein the support layer 2 in the BAW resonator comprises:

[0107] At least one total reflection structure surrounds the air slot M. The total reflection structure is used to prevent the leakage of the shear wave generated by the accompanying body sound wave. The propagation direction of the shear wave is perpendicular to the thickness direction Y.

[0108] A layer of total reflection structure surrounding the air slot M can be arranged around the air slot M, such as Figure 7 As shown, two layers of total reflection structures surrounding the air slots M may be provided. Of course, more layers of total reflection structures surrounding the air slots M may be provided. This can prevent the leakage of transverse wave back-rise generated by the accompanying body sound waves, thereby reducing or even preventing parasitic resonance.

[0109] See also Figure 8 A schematic diagram of a total reflection structure provided by an embodiment of the present invention, the total reflection structure includes:

[0110] A first structure 211 and a second structure 212;

[0111] The first structure 211 is located in the inner layer, and the second structure 212 is located in the outer layer. The impedance of the first structure 211 is lower than the impedance of the second structure 212 .

[0112] The material used for the first structure 211 may be a material with low impedance and good heat dissipation, such as metal materials such as copper, gold, silver, aluminum, non-metallic materials such as diamond, high thermal conductivity silicon, or a composite of the above materials; the material used for the second structure 212 may include at least one of silicon dioxide and high-resistance silicon.

[0113] In some embodiments, the thickness of the first structure 211 and the second structure 212 ranges from 8 to 13 um.

[0114] By forming the total reflection structural color resistance into a first structure 211 with low impedance in the inner layer and a second structure 212 with high impedance in the outer layer, it is possible to prevent shear wave leakage and effectively support the resonance layer 3. The total reflection structure can also be used to dissipate the heat in the air slot M and the heat of the total reflection layer, thereby further reducing the heat of the BAW resonator.

[0115] See also Fig. 9 A schematic diagram of the structure of another BAW resonator provided by an embodiment of the present invention, wherein the substrate 1 further includes a second through hole H2 penetrating in the thickness direction Y;

[0116] The total reflection structure extends to a side of the substrate 1 away from the resonance layer 3 through the second through hole H2 .

[0117] By providing a second through hole H2 penetrating the thickness direction Y on the substrate 1, and allowing the total reflection structure to extend through the second through hole H2 to a side of the substrate 1 away from the resonance layer 3, not only can the total reflection structure be used to prevent shear wave leakage, but the total reflection structure can also be used to transfer heat in the resonance layer 3 and the air slot M to the outside of the BAW resonator, thereby further preventing heat from accumulating inside the BAW resonator and reducing the heat of the BAW resonator.

[0118] See also Fig.10 A schematic diagram of the structure of another bulk acoustic wave resonator provided in an embodiment of the present invention,

[0119] The resonance layer 3 comprises:

[0120] The first electrode layer 31 is located on a side of the support layer 2 away from the substrate 1;

[0121] The piezoelectric layer 32 is located on a side of the first electrode layer 31 away from the substrate 1;

[0122] The second electrode layer 33 is located on a side of the piezoelectric layer 32 away from the base substrate 1 .

[0123] The materials used for the first electrode layer 31 and the second electrode layer 33 can be any one or any combination of platinum, aluminum, and molybdenum. The material used for the piezoelectric layer 32 can be aluminum nitride, zinc oxide, lead zirconate titanate (PZT), and the like.

[0124] In some embodiments, the thickness of the first electrode layer 31 and the second electrode layer 33 ranges from 0.15 to 0.25 um; the thickness of the piezoelectric layer 32 ranges from 0.8 to 2 um.

[0125] See also Fig.11 A schematic diagram of the structure of another BAW resonator provided by an embodiment of the present invention, wherein the BAW resonator further includes:

[0126] The metal layer 5 is located on a side of the second electrode layer 33 away from the base substrate 1 .

[0127] The material of the metal layer 5 can be heat dissipation materials such as copper, gold, silver, and aluminum.

[0128] By providing a metal layer 5 on a side of the second electrode layer 33 away from the base substrate 1, the impedance of the second electrode layer 33 can be changed by changing the thickness of the metal layer 5, thereby correcting the resonant frequency of the resonant layer 3, and the metal layer 5 can also be used to quickly dissipate the heat generated by the resonant layer 3, thereby further improving the heat dissipation effect of the bulk acoustic wave resonator.

[0129] Based on the same inventive concept, the present invention provides a method for manufacturing a bulk acoustic wave resonator. Please refer to the manufacturing diagram of the manufacturing method. Fig.12 , the preparation method comprises:

[0130] S1: providing a substrate 1;

[0131] Initially, the thickness of the base substrate 1 ranges from 300 to 400 um;

[0132] S2: forming a support layer 2 on one side of the base substrate 1; the support layer 2 has an air groove M penetrating in the thickness direction Y;

[0133] S3: Filling the sacrificial layer 6 in the air groove M;

[0134] The material of the sacrificial layer 6 is phospho-silicon glass (PSG) [i.e. SiO2 doped with P] or one of SiO2, polysilicon, metal and polymer. The thickness of the sacrificial layer 6 ranges from 8 to 13 um;

[0135] S4: forming a blind hole H penetrating the sacrificial layer 6 to the inside of the substrate 1, and forming a heat-conducting structure 4 in the blind hole H; after the heat-conducting structure 4 is formed, the heat-conducting structure 4 may be subjected to chemical mechanical polishing to remove impurities on the surface of the heat-conducting structure 4;

[0136] S5: forming a resonance layer 3 on a side of the heat conducting structure 4 away from the substrate 1, and removing the sacrificial layer 6;

[0137] When removing the sacrificial layer 6 , a hole may be drilled in the resonance layer 3 or the base substrate 1 , and then the sacrificial layer 6 is released.

[0138] S6: thinning the base substrate 1 so that the blind hole H becomes a first through hole H1 penetrating the thinned base substrate 1 .

[0139] The heat conducting structure 4 is exposed by thinning the base substrate 1 , and the original blind hole H is transformed into a first through hole H1 penetrating the thinned base substrate 1 ; the thickness of the thinned base substrate 1 may be, for example, 50 um.

[0140] See also Fig.13 A schematic diagram of forming a heat-conducting structure 4 provided in an embodiment of the present invention.

[0141] Forming a blind hole H penetrating the sacrificial layer 6 to the interior of the substrate 1 and forming a heat conducting structure 4 in the blind hole H can be achieved in the following manner:

[0142] S21: forming a groove H' in the sacrificial layer 6;

[0143] S22: drilling a hole from the bottom of the groove H' into the base substrate 1 to obtain a sub-blind hole H". The sub-blind hole H" penetrates the sacrificial layer 6 and enters the interior of the base substrate 1;

[0144] S23: filling the sub-blind hole H" with heat dissipation material to obtain a heat dissipation structure 42;

[0145] S24 : filling the groove H′ with a heat absorbing material to obtain a heat absorbing structure 41 ; the heat dissipation structure 42 and the heat absorbing structure 41 together constitute a heat conducting structure 4 .

[0146] A groove H' for accommodating the heat absorption structure 41 is first formed in the sacrificial layer 6, and then a hole is punched at the bottom of the groove H' to the inside of the base substrate 1 to obtain a sub-blind hole H" for accommodating the heat dissipation structure 42, and then a heat dissipation material is filled in the sub-blind hole H" to obtain the heat dissipation structure 42, and a heat absorption material is filled in the groove H' to obtain the heat absorption structure 41, so that the heat conducting structure 4 can be formed quickly and conveniently.

[0147] See also Fig.14 A schematic diagram of another method of forming a heat-conducting structure 4 provided in an embodiment of the present invention.

[0148] The blind hole H penetrating the sacrificial layer 6 to the inside of the substrate 1 and forming the heat conducting structure 4 in the blind hole H can also be achieved by the following methods:

[0149] S31: drilling a hole from the sacrificial layer 6 into the base substrate 1 to obtain a blind hole H;

[0150] S32: filling the blind hole H with heat dissipation material to obtain a heat dissipation structure 42;

[0151] S33: forming a heat absorbing structure 41 on a side of the heat dissipation structure 42 away from the base substrate 1 ; the heat absorbing structure 41 overlaps with the resonance structure; and the heat dissipation structure 42 and the heat absorbing structure 41 together constitute a heat conducting structure 4 .

[0152] A blind hole H is obtained by drilling from the sacrificial layer 6 to the inside of the base substrate 1, and a heat dissipation material is filled in the blind hole H to obtain a heat dissipation structure 42, and then a heat absorption structure 41 covering the heat dissipation structure 42, the sacrificial layer 6 and the supporting layer 2 is formed on the side of the heat dissipation structure 42 away from the base substrate 1, so that the resonant structure formed later can overlap with the heat dissipation structure 42, thereby maximizing the contact area between the heat dissipation structure 42 and the resonant structure, thereby facilitating the transfer of heat from the inside of the BAW resonator to the outside of the BAW resonator.

[0153] Based on the same inventive concept, an embodiment of the present invention provides an electronic device, comprising the BAW resonator as described above.

[0154] Although the preferred embodiments of the present invention have been described, those skilled in the art may make other changes and modifications to these embodiments once they have learned the basic creative concept. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and all changes and modifications that fall within the scope of the present invention.

[0155] Obviously, those skilled in the art can make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include these modifications and variations.

Claims

1. A bulk acoustic wave resonator, characterized in that: include: substrate substrate; The base substrate has a first through hole extending through the thickness direction; A supporting layer, located on one side of the substrate; The support layer has an air groove running through the thickness direction, and the first through hole is connected to the air groove; A resonance layer, located on a side of the support layer away from the substrate and covering the air slot, the resonance layer being used to convert an electrical signal into a bulk acoustic wave propagating in a thickness direction; The heat-conducting structure is located on a side of the resonance layer close to the base substrate; one end of the heat-conducting structure contacts the resonance layer, and the other end of the heat-conducting structure passes through the air groove and the first through hole in sequence.

2. The bulk acoustic wave resonator according to claim 1, characterized in that The supporting layer comprises: At least one total reflection structure surrounds the air slot, and the total reflection structure is used to prevent the leakage of the transverse wave generated along with the body acoustic wave, and the propagation direction of the transverse wave is perpendicular to the thickness direction.

3. The bulk acoustic wave resonator according to claim 2, characterized in that The total reflection structure comprises: A first structure and a second structure; The first structure is located in the inner layer, the second structure is located in the outer layer, and the impedance of the first structure is lower than the impedance of the second structure.

4. The bulk acoustic wave resonator according to claim 3, characterized in that The base substrate further includes a second through hole penetrating the thickness direction; The total reflection structure extends through the second through hole to a side of the substrate away from the resonance layer.

5. The bulk acoustic wave resonator according to any one of claims 1 to 4, characterized in that: The heat conducting structure comprises: a heat absorption structure, located on a side of the resonance layer close to the substrate, and in contact with at least a portion of the resonance layer and the air slot; The heat dissipation structure is located on a side of the heat absorption structure close to the base substrate; one end of the heat dissipation structure is connected to the heat absorption structure, and the other end is located in the first through hole.

6. The bulk acoustic wave resonator according to claim 5, characterized in that The orthographic projection area of ​​the heat absorption structure on the base substrate is larger than the orthographic projection area of ​​the heat dissipation structure on the base substrate.

7. The bulk acoustic wave resonator according to claim 5, characterized in that The orthographic projection of the heat absorption structure on the base substrate is located within the orthographic projection of the air groove on the base substrate.

8. The bulk acoustic wave resonator according to claim 5, characterized in that The heat absorption structure overlaps with the resonance layer.

9. The bulk acoustic wave resonator according to any one of claims 1 to 4, characterized in that: The resonance layer comprises: A first electrode layer is located on a side of the support layer away from the substrate; A piezoelectric layer, located on a side of the first electrode layer away from the substrate; The second electrode layer is located at a side of the piezoelectric layer away from the substrate.

10. The bulk acoustic wave resonator according to claim 9, characterized in that Also includes: The metal layer is located on a side of the second electrode layer away from the base substrate.

11. A method for manufacturing a bulk acoustic wave resonator, characterized in that: include: Providing a substrate; forming a support layer on one side of the substrate; The support layer has air grooves extending through the thickness direction; filling a sacrificial layer in the air groove; forming a blind hole penetrating the sacrificial layer to the interior of the substrate, and forming a heat conducting structure in the blind hole; forming a resonance layer on a side of the heat-conducting structure away from the substrate, and removing the sacrificial layer; The base substrate is thinned so that the blind hole becomes a first through hole penetrating the thinned base substrate.

12. The method according to claim 11, characterized in that: Forming a blind hole penetrating the sacrificial layer to the interior of the substrate, and forming a heat conducting structure in the blind hole, comprising: forming a groove in the sacrificial layer; Drilling a hole from the bottom of the groove into the substrate to obtain a sub-blind hole; the sub-blind hole penetrates the sacrificial layer and enters the interior of the substrate; Filling the sub-blind holes with heat dissipation material to obtain a heat dissipation structure; The groove is filled with a heat absorbing material to obtain a heat absorbing structure; the heat dissipation structure and the heat absorbing structure together constitute the heat conducting structure.

13. The manufacturing method according to claim 11, characterized in that: Forming a blind hole penetrating the sacrificial layer to the interior of the substrate, and forming a heat conducting structure in the blind hole, comprising: Drilling a hole from the sacrificial layer into the base substrate to obtain the blind hole; Filling the blind hole with heat dissipation material to obtain a heat dissipation structure; A heat absorbing structure is formed on a side of the heat dissipation structure away from the substrate; the heat absorbing structure overlaps with the resonance structure; and the heat dissipation structure and the heat absorbing structure together constitute the heat conducting structure.

14. An electronic device, characterized in that: The device comprises a bulk acoustic wave resonator as claimed in any one of claims 1 to 10.

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