Thin film bulk acoustic resonator with good heat dissipation, preparation method and filter

Abstract

The present invention relates to the technical field of thin film bulk acoustic wave resonators, and in particular to a thin film bulk acoustic wave resonator with excellent heat dissipation, a preparation method, and a filter. The thin film bulk acoustic wave resonator comprises a supporting substrate, a thermally conductive layer, a first electrode layer, a piezoelectric layer, a second electrode layer, and a passivation layer stacked in sequence. The first local electrode layer and the thermally conductive layer are connected to a first conductive pad, and the first conductive pad extends beyond the supporting substrate. The second local electrode layer and the thermally conductive layer are connected to a second conductive pad, and the second conductive pad extends beyond the supporting substrate. The thermally conductive layer is connected to a thermally conductive pad, and the thermally conductive pad extends beyond the supporting substrate. The first conductive pad, the second conductive pad, and the thermally conductive pad can promptly dissipate heat generated by the thin film bulk acoustic wave resonator to the outside of the supporting substrate, thereby enhancing the heat dissipation capability of the thin film bulk acoustic wave resonator and realizing a thin film bulk acoustic wave resonator with excellent heat dissipation characteristics.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of thin film bulk acoustic resonator, and particularly relates to a thin film bulk acoustic resonator with good heat dissipation, a preparation method and a filter. BACKGROUND

[0002] In a radio frequency front-end module of a wireless communication system, a filter is an indispensable important component, which mainly functions to screen signals, thereby realizing the functions of receiving and transmitting signals. Common filters in a mobile phone include a surface acoustic wave filter, a solid-state assembled bulk acoustic wave filter and a thin film bulk acoustic wave filter. As a new technology in recent years, a thin film bulk acoustic resonator (FBAR) and a filter including the thin film bulk acoustic resonator, i.e. a thin film bulk acoustic wave filter, have the characteristics of small volume, small insertion loss, high frequency and high power capacity, and are very suitable for next-generation high-frequency mobile terminal products.

[0003] The FBAR is roughly composed of three parts, i.e. a "sandwich" structure of a metal thin film / piezoelectric material / metal thin film stack, and its working principle is based on the piezoelectric effect and inverse piezoelectric effect of the piezoelectric material, which converts an electrical signal into an acoustic wave vibration of the piezoelectric material. The resonant frequency is inversely proportional to the stacking thickness in the vertical direction, and thus the working frequency of the FBAR is controlled by the stacking thickness. The higher the frequency is, the thinner the stacking structure is.

[0004] In a high-frequency FBAR product, the thickness of the "sandwich" structure is only several tens to several hundred nanometers. The reduction of the stacking thickness not only increases the film resistivity of the metal electrode, but also reduces the lattice quality of the piezoelectric material deposited or sputtered. The former increases the electrical loss of the FBAR, and the latter increases the acoustic wave loss of the FBAR. Most of these losses are in the form of heat dissipation. If the heat cannot be dissipated in time, the FBAR overheating not only limits the power capacity of the FBAR, but also greatly reduces the service life of the FBAR, and there is a possibility of being burned at any time.

[0005] Moreover, as Figure 17An existing film bulk acoustic resonator is shown, first, a metal material layer 42 is attached in the cavity of the lower substrate 39, specifically attached to the bottom and side of the cavity, and then the metal via 45 and the pad 46 are deposited by the back opening method. The "sandwich" structure of the film bulk acoustic resonator body is composed of the top electrode 44, the piezoelectric layer 43, and the bottom electrode 41, and the top electrode 44, the piezoelectric layer 43, and the bottom electrode 41 are located between the lower substrate 39 and the upper substrate 40, and the heat generated by the vibration can be conducted to the pad 46 on the back of the lower substrate 39 through the connection of the bottom electrode 41 and the metal material layer 42 and the metal via 45. Although this structure method improves the heat dissipation capacity of the device, the improvement effect is not obvious, and the connection of the bottom electrode 41 and the metal material layer 42 is too weak, which has a great risk of failure. At the same time, due to the large contact area of the metal material layer 42 and the cavity of the lower substrate 39, there may be a part of the electrical leakage. SUMMARY

[0006] The technical problem to be solved by the present application is to provide a film bulk acoustic resonator with good heat dissipation, a preparation method and a filter.

[0007] The technical scheme of the film bulk acoustic resonator with good heat dissipation provided by the present application is as follows:

[0008] The film bulk acoustic resonator comprises a support substrate, a heat conduction layer, a first electrode layer, a piezoelectric layer, a second electrode layer and a passivation layer which are sequentially stacked, wherein the support substrate is provided with a first groove, the heat conduction layer is located on the surface of the first groove of the support substrate, and the heat conduction layer covers each surface in the first groove.

[0009] The first electrode layer comprises a first local electrode layer and a second local electrode layer which are separated from each other, the first local electrode layer covers the opening of the first groove to form a first cavity, and the second local electrode layer is electrically connected with the second electrode layer.

[0010] The first local electrode layer and the heat conduction layer are connected with a first conductive pad, and the first conductive pad extends out of the support substrate, the second local electrode layer and the heat conduction layer are connected with a second conductive pad, and the second conductive pad extends out of the support substrate, and the heat conduction layer is connected with a heat conduction pad, and the heat conduction pad extends out of the support substrate.

[0011] The film bulk acoustic resonator with good heat dissipation provided by the present application has the following beneficial effects:

[0012] In one aspect, the heat generated by the film bulk acoustic resonator can be timely conducted out of the support substrate through the first conductive pad, the second conductive pad and the heat-conductive pad, the heat dissipation capacity of the film bulk acoustic resonator is enhanced, the thermal damage to the film bulk acoustic resonator is reduced, and the mechanical strength is high, thereby realizing a film bulk acoustic resonator with good heat dissipation characteristics and high mechanical strength.

[0013] Based on the above scheme, the film bulk acoustic resonator with good heat dissipation of the present application can be further improved as follows.

[0014] Further, the support substrate is provided with a sixth through hole extending to the first local electrode layer, the first conductive pad fills the sixth through hole and extends out of the support substrate, the support substrate is provided with a first through hole extending to the second local electrode layer, and the second conductive pad fills the first through hole and extends out of the support substrate.

[0015] Further, the four heat-conductive pads are respectively a first heat-conductive pad, a second heat-conductive pad, a third heat-conductive pad and a fourth heat-conductive pad.

[0016] The support substrate is provided with a second through hole and a third through hole extending to the heat-conductive layer, a fourth through hole and a fifth through hole, the first heat-conductive pad fills the second through hole and extends out of the support substrate, the second heat-conductive pad fills the third through hole and extends out of the support substrate, the third heat-conductive pad fills the fourth through hole and extends out of the support substrate, and the fourth heat-conductive pad fills the fifth through hole and extends out of the support substrate.

[0017] The beneficial effects of the above further scheme are: further enhancing the heat dissipation capacity of the film bulk acoustic resonator.

[0018] Further, the part of the first heat-conductive pad extending out of the support substrate, the part of the second heat-conductive pad extending out of the support substrate, the part of the third heat-conductive pad extending out of the support substrate and the part of the fourth heat-conductive pad extending out of the support substrate are connected.

[0019] Further, the passivation layer is arranged on the second electrode layer, and the second electrode layer is electrically connected with the second local electrode layer.

[0020] Further, the packaging cover plate provided with a second recess is further included, the piezoelectric layer is arranged on the opening of the second recess to form a second cavity, and the passivation layer and the second electrode layer are located in the second cavity and are in non-contact with the packaging cover plate.

[0021] Further, the material of the heat-conductive layer is diamond.

[0022] Furthermore, the first conductive pad and the second conductive pad are made of copper, tungsten, gold, titanium, aluminum or silver.

[0023] The technical solution of the present invention for preparing a thin film bulk acoustic resonator with good heat dissipation is as follows:

[0024] A first groove is formed on a supporting substrate, and a first blind hole, a second blind hole, a third blind hole, a fourth blind hole, a fifth blind hole, and a sixth blind hole are formed on a surface of the supporting substrate where the opening of the first groove is located, and the first blind hole, the second blind hole, the third blind hole, the fourth blind hole, the fifth blind hole, and the sixth blind hole are filled with metal;

[0025] A heat-conducting layer is prepared on the surface of the opening of the first groove of the support substrate, and the heat-conducting layer covers each surface in the first groove, and a sacrificial material is filled in the first groove covered with the heat-conducting layer to obtain a sacrificial material layer;

[0026] removing a portion of the heat-conducting layer covering the opening of the first blind hole to expose the metal at the opening of the first blind hole, removing a portion of the heat-conducting layer covering the opening of the sixth blind hole to expose the metal at the opening of the sixth blind hole, and preparing a first metal layer, where the first metal layer covers the sacrificial material layer, the remaining portion of the heat-conducting layer, the metal at the opening of the first blind hole, and the metal at the opening of the sixth blind hole, and patterning the first metal layer to obtain a first electrode layer;

[0027] The first electrode layer includes a first partial electrode layer and a second partial electrode layer separated from each other, the first partial electrode layer is covered on the opening of the first groove and the metal at the opening of the sixth blind hole, and the second partial electrode layer is covered on the metal at the opening of the first blind hole;

[0028] preparing a piezoelectric layer, wherein the piezoelectric layer covers the first local electrode layer, the second local electrode layer, and the exposed portion of the thermal conductive layer;

[0029] Sequentially preparing a second electrode layer and a passivation layer on the piezoelectric layer, wherein the passivation layer covers the second electrode layer;

[0030] electrically connecting the other end of the second electrode layer to the second partial electrode layer;

[0031] removing the sacrificial material layer to obtain a first cavity;

[0032] The packaging cover plate with the second groove is prepared, the piezoelectric layer is covered on the opening of the second groove to form a second cavity, the passivation layer and the second electrode layer are located in the second cavity, and the passivation layer and the second electrode layer are both in non-contact with the packaging cover plate.

[0033] The back of the support substrate is thinned to expose the metal at the bottom of the first blind hole, the metal at the bottom of the second blind hole, the metal at the bottom of the third blind hole, the metal at the bottom of the fourth blind hole, the metal at the bottom of the fifth blind hole and the metal at the bottom of the sixth blind hole.

[0034] The fourth metal layer for covering the bottom of the first blind hole is prepared to obtain a second conductive pad, the fifth metal layer for covering the bottom of the second blind hole is prepared to obtain a first heat-conductive pad, the sixth metal layer for covering the bottom of the third blind hole is prepared to obtain a second heat-conductive pad, the seventh metal layer for covering the bottom of the fourth blind hole is prepared to obtain a third heat-conductive pad, the eighth metal layer for covering the bottom of the fifth blind hole is prepared to obtain a fourth heat-conductive pad, and the ninth metal layer for covering the bottom of the sixth blind hole is prepared to obtain a first conductive pad.

[0035] The preparation method of the film bulk acoustic resonator with good heat dissipation has the following beneficial effects:

[0036] The film bulk acoustic resonator with good heat dissipation characteristics and high mechanical strength can be prepared.

[0037] The film bulk acoustic resonator with good heat dissipation characteristics and high mechanical strength can be prepared. BRIEF DESCRIPTION OF DRAWINGS

[0038] Figure 1 The structure diagram of the film bulk acoustic resonator with good heat dissipation according to the embodiment of the present application is shown in the figure.

[0039] Figure 2 The flowchart of the preparation method of the film bulk acoustic resonator with good heat dissipation according to the embodiment of the present application is shown in the figure.

[0040] Figure 3 The cross-sectional structure diagram of the support substrate after the first groove is formed is shown in the figure.

[0041] Figure 4 The cross-sectional structure diagram of the support substrate after the blind hole is formed is shown in the figure.

[0042] Figure 5A cross-sectional structure schematic diagram after filling metal in the first blind hole, the second blind hole, the third blind hole, the fourth blind hole, the fifth blind hole and the sixth blind hole;

[0043] Figure 6 A cross-sectional structure schematic diagram after preparing the heat conduction layer;

[0044] Figure 7 A cross-sectional structure schematic diagram after filling the sacrificial material;

[0045] Figure 8 A cross-sectional structure schematic diagram after patterning the heat conduction layer;

[0046] Figure 9 A cross-sectional structure schematic diagram after preparing the first electrode layer;

[0047] Figure 10 A cross-sectional structure schematic diagram after preparing the piezoelectric layer;

[0048] Figure 11 A cross-sectional structure schematic diagram after preparing the second electrode layer;

[0049] Figure 12 A cross-sectional structure schematic diagram after preparing the passivation layer;

[0050] Figure 13 A cross-sectional structure schematic diagram after electrically connecting the other end of the second electrode layer and the second local electrode layer;

[0051] Figure 14 A cross-sectional structure schematic diagram after removing the sacrificial material layer;

[0052] Figure 15 A cross-sectional structure schematic diagram after covering the piezoelectric layer on the opening of the second groove;

[0053] Figure 16 A cross-sectional structure schematic diagram after thinning the back of the support substrate;

[0054] Figure 17 A cross-sectional structure schematic diagram of an existing film bulk acoustic resonator;

[0055] In the drawings, the components represented by each reference numeral are listed as follows:

[0056] 10. Support substrate; 101. First groove; 102. First blind hole; 103. Second blind hole; 104. Third blind hole; 105. Fourth blind hole; 106. Fifth blind hole; 107. Sixth blind hole; 11. Metal filled in the first blind hole; 12. Thermal conductive layer; 13. Sacrificial material layer; 14. First electrode layer; 141. First local electrode layer; 142. Second local electrode layer; 15. Piezoelectric layer; 16. Second electrode layer; 17. Passivation layer; 18. Third metal layer; 19. First cavity; 20. Package cover; 21. Second cavity; 22. Fourth metal layer; 23. Fifth metal layer; 24. Sixth metal layer; 25. Seventh metal layer, 26. Eighth metal layer; 27. Ninth metal layer; 28. First conductive pad; 29. ​​Second conductive pad; 3 0. First thermal pad; 31. Second thermal pad; 32. Third thermal pad; 33. Fourth thermal pad; 34. Metal filled in the second blind hole; 35. Metal filled in the third blind hole; 36. Metal filled in the fourth blind hole; 37. Metal filled in the fifth blind hole; 38. Metal filled in the sixth blind hole; 39. Lower substrate of an existing thin film bulk acoustic resonator; 40. Upper substrate of an existing thin film bulk acoustic resonator; 41. Bottom electrode of an existing thin film bulk acoustic resonator; 42. Metal material of an existing thin film bulk acoustic resonator; 43. Piezoelectric layer of an existing thin film bulk acoustic resonator; 44. Top electrode of an existing thin film bulk acoustic resonator; 45. Metal via of an existing thin film bulk acoustic resonator; 46. Pad of an existing thin film bulk acoustic resonator. DETAILED DESCRIPTION

[0057] like Figure 1 As shown, a thin film bulk acoustic resonator with good heat dissipation according to an embodiment of the present invention includes a supporting substrate 10, a thermal conductive layer 12, a first electrode layer 14, a piezoelectric layer 15, a second electrode layer 16, and a passivation layer 17 stacked in sequence, wherein the supporting substrate 10 is provided with a first groove 101, the thermal conductive layer 12 is located on the surface of the supporting substrate 10 where the first groove 101 is located, and the thermal conductive layer 12 covers each surface within the first groove 101;

[0058] The first electrode layer 14 includes a first partial electrode layer 141 and a second partial electrode layer 142 separated from each other. The first partial electrode layer 141 covers the opening of the first groove 101 to form a first cavity 19. The second partial electrode layer 142 is electrically connected to the second electrode layer 16.

[0059] The first partial electrode layer 141 and the heat conduction layer 12 are connected with a first conductive pad 28, and the first conductive pad 28 extends out of the support substrate 10. The second partial electrode layer 142 and the heat conduction layer 12 are connected with a second conductive pad 29, and the second conductive pad 29 extends out of the support substrate 10. The heat conduction layer 12 is connected with a heat conduction pad, and the heat conduction pad extends out of the support substrate 10.

[0060] The material of the support substrate 10 is a substrate material commonly used in semiconductor processes, including but not limited to silicon Si, germanium Ge, sapphire Al2O3, quartz SiO2, silicon carbide SiC, organic polymers, etc.

[0061] The material of the heat conduction layer 12 is diamond. Diamond has high thermal conductivity, further enhancing the heat dissipation capability of the film bulk acoustic resonator. The material of the heat conduction layer 12 can also be set according to actual conditions.

[0062] The material of the first electrode layer 14 and the second electrode layer 16 is a metal material with good electrical conductivity, including but not limited to molybdenum Mo, copper Cu, tungsten W, gold Au, titanium Ti, aluminum Al, platinum Pt, etc.

[0063] The material of the piezoelectric layer 15 is a piezoelectric material, including but not limited to aluminum nitride AlN, lithium niobate LiNbO3, lithium tantalate LiTaO3, etc.

[0064] The material of the passivation layer 17 is silicon dioxide SiO2, aluminum nitride AlN, etc.

[0065] The cross section of the first groove 101 is trapezoidal. The first groove 101 can also be set to other shapes according to actual conditions.

[0066] The implementation of the electrical connection between the second partial electrode layer 142 and the second electrode layer 16 is as follows:

[0067] Etching is performed on the piezoelectric layer 15 to expose the second partial electrode layer 142, and then metal is deposited to form a third metal layer 18 covering one end of the second electrode layer 16. The electrical connection between the second partial electrode layer 142 and the second electrode layer 16 is achieved through the third metal layer 18. The material of the third metal layer 18 is copper, tungsten, gold, titanium, aluminum, or silver.

[0068] A sixth through hole extending to the first partial electrode layer 141 is formed on the support substrate 10. The first conductive pad 28 fills the fourth through hole and extends out of the support substrate 10. A first through hole extending to the second partial electrode layer 142 is formed on the support substrate 10. The second conductive pad 29 fills the first through hole and extends out of the support substrate 10. Specifically:

[0069] 1) The specific structure of the first conductive pad 28 is that a sixth via hole is formed on the support substrate 10 to extend to the first partial electrode layer 141, the bottom of the sixth via hole exposes the first partial electrode layer 141, copper, tungsten, gold, titanium, aluminum or silver and the like are deposited in the sixth via hole, and the metal extending out of the support substrate 10 is the ninth metal layer 27, that is, the first conductive pad 28.

[0070] 2) The specific structure of the second conductive pad 29 is that a first via hole is formed on the support substrate 10 to extend to the second partial electrode layer 142, that is, the bottom of the first via hole exposes the second partial electrode layer 142, copper, tungsten, gold, titanium, aluminum or silver and the like are deposited in the first via hole, and the metal extending out of the support substrate 10 is the fourth metal layer 22, that is, the second conductive pad 29.

[0071] Among them, the specific structure of the heat conduction pad is that a via hole is formed on the support substrate 10 to expose the heat conduction layer 12, and copper, tungsten, gold, titanium, aluminum or silver and the like are deposited in the via hole and extend out of the support substrate 10, and the metal deposited in the via hole and extending out of the support substrate 10 is the heat conduction pad; a plurality of conductive pads and a plurality of heat conduction pads can be provided according to actual conditions.

[0072] Through the first conductive pad 28, the second conductive pad 29, the conductive layer 12 and the heat conduction pad as the first heat conduction pad 30, the second heat conduction pad 31, the third heat conduction pad 32 and the fourth heat conduction pad 33 in the following, the heat generated by the film bulk acoustic resonator can be timely conducted out of the support substrate 10, the heat dissipation capacity of the film bulk acoustic resonator is enhanced, the thermal damage to the film bulk acoustic resonator is reduced, and the mechanical strength is high, thereby realizing a film bulk acoustic resonator with good heat dissipation characteristics and high mechanical strength.

[0073] Moreover, in the existing thin film bulk acoustic resonator, the connection between the bottom electrode 41 and the metal material layer 42 is achieved by connecting the plane of the bottom electrode 41 with the sidewall of the metal material layer 42. The thickness of the sidewall of the metal material layer 42 is generally less than 2 microns, that is, the width of the connection surface is not more than 2 microns. In the present application, the connection mode is a metal via hole with a diameter of more than 10 microns. The metal 1 filled in the first blind hole and the metal 38 filled in the sixth blind hole can be regarded as metal columns 38 and 11. The effect of conduction and heat conduction is obvious. The metal via hole is specifically reflected in the connection between the first partial electrode layer 141, the metal 38 filled in the sixth blind hole, and the ninth metal layer 27, and the connection between the second partial electrode layer 142, the metal 11 filled in the first blind hole, and the fourth metal layer 22. Because the metal material layer 42 of the existing thin film bulk acoustic resonator is in contact with the entire cavity, the radiation area is much larger than the radiation area of the metal via hole in contact with the support substrate 10 in the present application. Therefore, the electrical leakage is relatively large, that is, the electrical leakage of the thin film bulk acoustic resonator of the present application is small.

[0074] Optionally, in the above technical solution, four heat conduction pads are included, which are a first heat conduction pad 30, a second heat conduction pad 31, a third heat conduction pad 32, and a fourth heat conduction pad 33.

[0075] The second through hole, the third through hole 104, the fourth through hole, and the fifth through hole extending to the heat conduction layer 12 are formed on the support substrate 10. The first heat conduction pad 30 fills the second through hole and extends to the outside of the support substrate 10. The second heat conduction pad 31 fills the third through hole and extends to the outside of the support substrate 10. The third heat conduction pad 32 fills the fourth through hole and extends to the outside of the support substrate 10. The fourth heat conduction pad 33 fills the fifth through hole and extends to the outside of the support substrate 10. The heat dissipation capacity of the thin film bulk acoustic resonator can be further enhanced.

[0076] The specific implementation modes of the first heat conduction pad 30, the second heat conduction pad 31, the third heat conduction pad 32, and the fourth heat conduction pad 33 are as follows:

[0077] The second through hole, the third through hole, the fourth through hole, and the fifth through hole extending to the heat conduction layer 12 are formed on the support substrate 10, that is, the bottom of the second through hole, the bottom of the third through hole, the bottom of the fourth through hole, and the bottom of the fifth through hole all expose the heat conduction layer 12. Copper, tungsten, gold, titanium, aluminum, or silver and other metals are deposited in the second through hole, the third through hole, the fourth through hole, and the fifth through hole and extend to the outside of the support substrate 10. Then:

[0078] 1) The metal deposited in the second through hole and extending to the outside of the support substrate 10, that is, the fifth metal layer 23, is the first heat conduction pad 30.

[0079] 2) the metal deposited in the third via hole and the metal extending out of the support substrate 10, i.e. the sixth metal layer 24, is the second heat-conductive pad 31;

[0080] 3) the metal deposited in the fourth via hole and the metal extending out of the support substrate 10, i.e. the seventh metal layer 25, is the third heat-conductive pad 32;

[0081] 4) the metal deposited in the fifth via hole and the metal extending out of the support substrate 10, i.e. the eighth metal layer 26, is the fourth heat-conductive pad 33.

[0082] Optionally, in the above technical solution, the part of the first heat-conductive pad 30 extending out of the support substrate 10, the part of the second heat-conductive pad 31 extending out of the support substrate 10, the part of the third heat-conductive pad 32 extending out of the support substrate 10, and the part of the fourth heat-conductive pad 33 extending out of the support substrate 10 are connected, that is, the fifth metal layer 23 of the first heat-conductive pad 30, the sixth metal layer 24 of the second heat-conductive pad 31, the seventh metal layer 25 of the third heat-conductive pad 32, and the eighth metal layer 26 of the fourth heat-conductive pad 33 are connected, and the area after connection is slightly larger than the first cavity 19.

[0083] Optionally, in the above technical solution, the passivation layer 17 is arranged on the second electrode layer 16, and the second electrode layer 16 is electrically connected with the second local electrode layer 142, which can be specifically as follows:

[0084] The passivation layer 17 is arranged on one end of the second electrode layer 16, and the passivation layer 17 is connected with the piezoelectric layer 15, and the other end of the second electrode layer 16 is electrically connected with the second local electrode layer 142. That is, the two ends of the second electrode layer 16 are respectively covered with the passivation layer 17 and the third metal layer 18.

[0085] Optionally, in the above technical solution, the packaging cover plate 20 provided with the second recess is further included, the piezoelectric layer 15 is arranged on the opening of the second recess to form the second cavity 21, and the passivation layer 17 and the second electrode layer 16 are both located in the second cavity 21 and are both in non-contact with the packaging cover plate 20.

[0086] The packaging cover plate 20 is made of a substrate material commonly used in semiconductor processes, including but not limited to silicon Si, germanium Ge, sapphire Al2O3, quartz SiO2, silicon carbide SiC, organic polymers, etc., and the packaging cover plate 20 plays a protective role.

[0087] The cross section of the second recess is rectangular, and the second recess can also be provided in other shapes according to actual conditions.

[0088] For example, the piezoelectric layer 15 is arranged on the opening of the first recess to form the first cavity 19, and the passivation layer 17 and the second electrode layer 16 are both located in the first cavity 19 and are both in non-contact with the packaging cover plate 20. Figure 2As shown, the preparation method for preparing a thin film bulk acoustic resonator with good heat dissipation according to an embodiment of the present application comprises the following steps:

[0089] S1, a first recess 101 is formed on a support substrate 10, and a first blind hole 102, a second blind hole 103, a third blind hole 104, a fourth blind hole 105, a fifth blind hole 106 and a sixth blind hole 107 are formed on the surface where the opening of the first recess 101 is located on the support substrate 10, and the first blind hole 102, the second blind hole 103, the third blind hole 104, the fourth blind hole 105, the fifth blind hole 106 and the sixth blind hole 107 are filled with metal;

[0090] S2, a heat conduction layer 12 is prepared on the surface where the opening of the first recess 101 is located on the support substrate 10, and the heat conduction layer 12 covers each surface in the first recess 101, and a sacrificial material is filled in the first recess 101 covered with the heat conduction layer 12 to obtain a sacrificial material layer 13;

[0091] S3, part of the heat conduction layer 12 covering the opening of the first blind hole 102 is removed to expose the metal at the opening of the first blind hole 102, part of the heat conduction layer 12 covering the opening of the sixth blind hole 107 is removed to expose the metal at the opening of the sixth blind hole 107, and a first metal layer is prepared, which covers the sacrificial material layer 13, the remaining part of the heat conduction layer 12, the metal at the opening of the first blind hole 102 and the metal at the opening of the sixth blind hole 107, and the first metal layer is patterned to obtain a first electrode layer 14;

[0092] S4, the first electrode layer 14 comprises a first local electrode layer 141 and a second local electrode layer 142 which are separated from each other, the first local electrode layer 141 covers the metal at the opening of the first recess 101 and the opening of the sixth blind hole 107, and the second local electrode layer 142 covers the metal at the opening of the first blind hole 102;

[0093] S5, a piezoelectric layer 15 is prepared, which covers the first local electrode layer 141, the second local electrode layer 142 and the exposed part of the heat conduction layer 12;

[0094] S6, a second electrode layer 16 and a passivation layer 17 are sequentially prepared on the piezoelectric layer 15, and the passivation layer 17 covers the second electrode layer 16;

[0095] S7, the second electrode layer 16 and the second local electrode layer 142 are electrically connected; specifically, the passivation layer 17 covers one end of the second electrode layer 16, and the passivation layer 17 is connected with the piezoelectric layer 15, and the other end of the second electrode layer 16 is electrically connected with the second local electrode layer 142. That is, the two ends of the second electrode layer 16 are respectively covered with the passivation layer 17 and a third metal layer 18.

[0096] S8, removing the sacrificial material layer 13 to obtain a first cavity 19;

[0097] S9, preparing a packaging cover plate 20 with a second groove, covering the piezoelectric layer 15 on the opening of the second groove to form a second cavity 21, and the passivation layer 17 and the second electrode layer 16 are both located in the second cavity 21, and the passivation layer 17 and the second electrode layer 16 are both located in the second cavity 21, and the passivation layer 17 and the second electrode layer 16 are both in contact with the packaging cover plate 20;

[0098] S10, thinning the back of the support substrate 10 to expose the metal at the bottom of the first blind hole 102, the metal at the bottom of the second blind hole 103, the metal at the bottom of the third blind hole 104, the metal at the bottom of the fourth blind hole 105, the metal at the bottom of the fifth blind hole 106 and the metal at the bottom of the sixth blind hole 107;

[0099] S11, preparing a fourth metal layer 22 for covering the bottom of the first blind hole 102 to obtain a second conductive pad 29, preparing a fifth metal layer 23 for covering the bottom of the second blind hole 103 to obtain a first heat-conducting pad 30, preparing a sixth metal layer 24 for covering the bottom of the third blind hole 104 to obtain a second heat-conducting pad 31, preparing a seventh metal layer 25 for covering the bottom of the fourth blind hole 105 to obtain a third heat-conducting pad 32, preparing an eighth metal layer 26 for covering the bottom of the fifth blind hole 106 to obtain a fourth heat-conducting pad 33, and preparing a ninth metal layer 27 for covering the bottom of the sixth blind hole 107 to obtain a first conductive pad 28.

[0100] The application provides a preparation method for preparing a thin film bulk acoustic resonator with good heat dissipation.

[0101] S10, a first groove 101 is formed on the support substrate 10, and specifically:

[0102] A first groove 101 with a certain depth is formed on the support substrate 10 through a photoetching and etching process, and the depth can be set according to actual conditions, for example, the depth of the first groove 101 is 1-10 microns. Figure 3 as shown in the figure;

[0103] S11, a blind hole is formed, and specifically:

[0104] The first blind hole 102, the second blind hole 103, the third blind hole 104, the fourth blind hole 105, the fifth blind hole 106 and the sixth blind hole 107 are formed on the surface where the opening of the first groove 101 of the support substrate 10 is located through a photoetching and etching process. Figure 4 as shown in the figure;

[0105] S12, filling the first blind hole 102, the second blind hole 103, the third blind hole 104, the fourth blind hole 105, the fifth blind hole 106 and the sixth blind hole 107 with metal by sputtering, evaporation or plating process, wherein the metal 11 filled in the first blind hole, the metal 34 filled in the second blind hole, the metal 35 filled in the third blind hole, the metal 36 filled in the fourth blind hole, the metal 37 filled in the fifth blind hole and the metal 38 filled in the sixth blind hole are as shown in FIG. 2. Figure 5

[0106] S13, preparing the heat-conducting layer 12, specifically:

[0107] The heat-conducting layer 12 is prepared on the surface of the opening of the first groove 101 of the support substrate 10 by sputtering, evaporation, coating or chemical vapor deposition process, and the heat-conducting layer 12 covers each surface in the first groove 101, as shown in FIG. 3. Figure 6

[0108] S14, filling the first groove 101 covered with the heat-conducting layer 12 with a sacrificial material to obtain a sacrificial material layer 13, as shown in FIG. 4. Figure 7

[0109] S15, patterning the heat-conducting layer 12 by photolithography, etching or the like to remove part of the heat-conducting layer 12 covering the opening of the first blind hole 102 to expose the metal at the opening of the first blind hole 102, and remove part of the heat-conducting layer 12 covering the opening of the sixth blind hole 107 to expose the metal at the opening of the sixth blind hole 107, as shown in FIG. 5. Figure 8

[0110] S16, preparing the first electrode layer 14, specifically:

[0111] A first metal layer is prepared, which covers the sacrificial material layer 13, the remaining part of the heat-conducting layer 12, the metal at the opening of the first blind hole 102 and the metal at the opening of the sixth blind hole 107, and the first metal layer is patterned by photolithography, etching or the like to obtain the first electrode layer 14.

[0112] The first electrode layer 14 includes a first partial electrode layer 141 and a second partial electrode layer 142 separated from each other, the first partial electrode layer 141 covers the opening of the first groove 101 and the metal at the opening of the sixth blind hole 107, and the second partial electrode layer 142 covers the metal at the opening of the first blind hole 102, as shown in FIG. 6. Figure 9

[0113] S17, preparing the piezoelectric layer 15, specifically:

[0114] ​​​​​The piezoelectric layer 15 is prepared by sputtering or chemical vapor deposition process, and is arranged on the first local electrode layer 141, the second local electrode layer 142 and the exposed part of the heat-conducting layer 12, as shown in Figure 10 ;

[0115] S18, the second electrode layer 16 is prepared, specifically:

[0116] A second metal layer is prepared on the piezoelectric layer 15, and the second metal layer is patterned by photolithography, etching and other processes, to obtain the second electrode layer 16, as shown in Figure 11 ;

[0117] S19, the passivation layer 17 is prepared, specifically:

[0118] A layer of metal material is deposited on the piezoelectric layer 15, and the layer of metal material is patterned to obtain the passivation layer 17, or the passivation layer 17 is directly deposited, the passivation layer 17 covers one end of the second electrode layer 16, and the passivation layer 17 is connected with the piezoelectric layer 15, as shown in Figure 12 ;

[0119] S20, the other end of the second electrode layer 16 is electrically connected with the second local electrode layer 142, specifically:

[0120] Etching is performed on the piezoelectric layer 15 to expose the second local electrode layer 142, then a metal layer is deposited to form a third metal layer 18, and the third metal layer 18 covers one end of the second electrode layer 16, and the electrical connection between the second local electrode layer 142 and the second electrode layer 16 is realized through the third metal layer 18, as shown in Figure 13 .

[0121] S21, the sacrificial material layer 13 is removed to obtain the first cavity 19, as shown in Figure 14 ;

[0122] S22, the packaging cover plate 20 with a second groove is prepared, the piezoelectric layer 15 is arranged on the opening of the second groove to form a second cavity 21, the passivation layer 17 and the second electrode layer 16 are both located in the second cavity 21, and the passivation layer 17 and the second electrode layer 16 are both located in the second cavity 21, and the passivation layer 17 and the second electrode layer 16 are both in non-contact with the packaging cover plate 20, as shown in Figure 15 ;

[0123] S23, the back of the support substrate 10 is thinned to expose the metal at the bottom of the first blind hole 102, the metal at the bottom of the second blind hole 103, the metal at the bottom of the third blind hole 104, the metal at the bottom of the fourth blind hole 105, the metal at the bottom of the fifth blind hole 106 and the metal at the bottom of the sixth blind hole 107, at this time, the first blind hole 102 becomes a first through hole, the second blind hole 103 becomes a second through hole, the third blind hole 104 becomes a third through hole, the fourth blind hole 105 becomes a fourth through hole, the fifth blind hole 106 becomes a fifth through hole, and the sixth blind hole 107 becomes a sixth through hole, as shown in Figure 16

[0124] S24, a fourth metal layer 22 is prepared to cover the bottom of the first blind hole 102 to obtain a second conductive pad 29, a fifth metal layer 23 is prepared to cover the bottom of the second blind hole 103 to obtain a first heat-conductive pad 30, a sixth metal layer 24 is prepared to cover the bottom of the third blind hole 104 to obtain a second heat-conductive pad 31, a seventh metal layer 25 is prepared to cover the bottom of the fourth blind hole 105 to obtain a third heat-conductive pad 32, an eighth metal layer 26 is prepared to cover the bottom of the fifth blind hole 106 to obtain a fourth heat-conductive pad 33, and a ninth metal layer 27 is prepared to cover the bottom of the sixth blind hole 107 to obtain a first conductive pad 28, thereby obtaining a thin film bulk acoustic resonator with good heat dissipation as shown in Figure 1

[0125] In the above, the metal extending out of the support substrate 10 of the first conductive pad 28 is the ninth metal layer 27, the metal extending out of the support substrate 10 of the second conductive pad 29 is the fourth metal layer 22, the metal extending out of the support substrate 10 of the first heat-conductive pad 30 is the fifth metal layer 23, the metal extending out of the support substrate 10 of the second heat-conductive pad 31 is the sixth metal layer 24, the metal extending out of the support substrate 10 of the third heat-conductive pad 32 is the seventh metal layer 25, and the metal extending out of the support substrate 10 of the fourth heat-conductive pad 33 is the eighth metal layer 26.

[0126] The thin film bulk acoustic resonator with good heat dissipation according to any one of the above.

[0127] In the present application, the terms "first", "second" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined with "first", "second" can explicitly or implicitly include at least one of the features. In the description of the present application, the meaning of "a plurality of" is at least two, such as two, three, etc., unless otherwise specifically limited.

[0128] ​​In the description of the specification, the description of the terms "one embodiment", "some embodiments", "an example", "a specific example", or "some examples" etc. means that the specific features, structures, materials or characteristics described in connection with the embodiment or example are contained in at least one embodiment or example of the present application. In the specification, the illustrative description of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any suitable manner in any one or more embodiments or examples. In addition, the person skilled in the art can combine and combine the different embodiments or examples described in the specification and the features of the different embodiments or examples without contradiction.

[0129] Although the embodiments of the present application have been shown and described above, it is understood that the above-described embodiments are exemplary and are not to be construed as limiting the present application, and those skilled in the art can make changes, modifications, replacements and variations to the above-described embodiments within the scope of the present application.

Claims

1. A thin film bulk acoustic resonator with good heat dissipation, characterized in that: The device comprises a support substrate, a heat-conducting layer, a first electrode layer, a piezoelectric layer, a second electrode layer, and a passivation layer stacked in sequence, wherein the support substrate is provided with a first groove, the heat-conducting layer is located on the surface of the support substrate where the first groove is located, and the heat-conducting layer covers each surface within the first groove; The first electrode layer includes a first partial electrode layer and a second partial electrode layer separated from each other, the first partial electrode layer is covered on the opening of the first groove to form a first cavity, and the second partial electrode layer is electrically connected to the second electrode layer; The first local electrode layer and the heat-conducting layer are connected to a first conductive pad, and the first conductive pad extends outside the supporting substrate; the second local electrode layer and the heat-conducting layer are connected to a second conductive pad, and the second conductive pad extends outside the supporting substrate; the heat-conducting layer is connected to a heat-conducting pad, and the heat-conducting pad extends outside the supporting substrate; A sixth through hole extending to the first local electrode layer is defined on the support substrate, the first conductive pad fills the sixth through hole and extends outside the support substrate, a first through hole extending to the second local electrode layer is defined on the support substrate, the second conductive pad fills the first through hole and extends outside the support substrate; A sixth through hole extending to the first local electrode layer is opened on the supporting substrate, the first local electrode layer is exposed at the bottom of the sixth through hole, metal is deposited in the sixth through hole, and the deposited metal extends outside the supporting substrate. The metal deposited in the sixth through hole and the metal extending outside the supporting substrate are the first conductive pad; a first through hole extending to the second local electrode layer is opened on the supporting substrate, the second local electrode layer is exposed at the bottom of the first through hole, metal is deposited in the first through hole, and the deposited metal extends outside the supporting substrate. The metal deposited in the first through hole and the metal extending outside the supporting substrate are the second conductive pad.

2. The thin film bulk acoustic resonator with good heat dissipation according to claim 1, characterized in that: It includes four thermally conductive pads, which are respectively a first thermally conductive pad, a second thermally conductive pad, a third thermally conductive pad and a fourth thermally conductive pad; The support substrate is provided with a second through hole, a third through hole, a fourth through hole and a fifth through hole extending to the heat-conducting layer, the first heat-conducting pad fills the second through hole and extends outside the support substrate, the second heat-conducting pad fills the third through hole and extends outside the support substrate, the third heat-conducting pad fills the fourth through hole and extends outside the support substrate, and the fourth heat-conducting pad fills the fifth through hole and extends outside the support substrate.

3. The thin film bulk acoustic resonator with good heat dissipation according to claim 2, characterized in that: The portion of the first thermal conductive pad extending outside the support substrate, the portion of the second thermal conductive pad extending outside the support substrate, the portion of the third thermal conductive pad extending outside the support substrate, and the portion of the fourth thermal conductive pad extending outside the support substrate are connected.

4. The thin film bulk acoustic resonator with good heat dissipation according to claim 1, characterized in that: The passivation layer covers the second electrode layer, and the second electrode layer is electrically connected to the second local electrode layer.

5. The thin film bulk acoustic resonator with good heat dissipation according to any one of claims 1 to 4, characterized in that: It also includes a packaging cover plate having a second groove, the piezoelectric layer is covered on the opening of the second groove to form a second cavity, and the passivation layer and the second electrode layer are both located in the second cavity, and the passivation layer and the second electrode layer are both non-contact with the packaging cover plate.

6. A thin film bulk acoustic resonator with good heat dissipation according to any one of claims 1 to 4, characterized in that: The heat conducting layer is made of diamond.

7. A thin film bulk acoustic resonator with good heat dissipation according to any one of claims 1 to 4, characterized in that: The first conductive pad and the second conductive pad are made of copper, tungsten, gold, titanium, aluminum or silver.

8. A method for preparing a thin film bulk acoustic resonator with good heat dissipation, characterized in that: include: A first groove is formed on a supporting substrate, and a first blind hole, a second blind hole, a third blind hole, a fourth blind hole, a fifth blind hole, and a sixth blind hole are formed on a surface of the supporting substrate where the opening of the first groove is located, and the first blind hole, the second blind hole, the third blind hole, the fourth blind hole, the fifth blind hole, and the sixth blind hole are filled with metal; A heat-conducting layer is prepared on the surface of the opening of the first groove of the support substrate, and the heat-conducting layer covers each surface in the first groove, and a sacrificial material is filled in the first groove covered with the heat-conducting layer to obtain a sacrificial material layer; removing a portion of the heat-conducting layer covering the opening of the first blind hole to expose the metal at the opening of the first blind hole, removing a portion of the heat-conducting layer covering the opening of the sixth blind hole to expose the metal at the opening of the sixth blind hole, and preparing a first metal layer, where the first metal layer covers the sacrificial material layer, the remaining portion of the heat-conducting layer, the metal at the opening of the first blind hole, and the metal at the opening of the sixth blind hole, and patterning the first metal layer to obtain a first electrode layer; The first electrode layer includes a first partial electrode layer and a second partial electrode layer separated from each other, the first partial electrode layer is covered on the opening of the first groove and the metal at the opening of the sixth blind hole, and the second partial electrode layer is covered on the metal at the opening of the first blind hole; preparing a piezoelectric layer, wherein the piezoelectric layer covers the first local electrode layer, the second local electrode layer, and the exposed portion of the thermal conductive layer; Sequentially preparing a second electrode layer and a passivation layer on the piezoelectric layer, wherein the passivation layer covers the second electrode layer; electrically connecting the other end of the second electrode layer to the second partial electrode layer; removing the sacrificial material layer to obtain a first cavity; Prepare a package cover plate having a second groove, so that the piezoelectric layer covers the opening of the second groove to form a second cavity, and the passivation layer and the second electrode layer are both located in the second cavity, and the passivation layer and the second electrode layer are both located in the second cavity, and the passivation layer and the second electrode layer are not in contact with the package cover plate; performing a thinning process on the back of the supporting substrate to expose the metal at the bottom of the first blind hole, the metal at the bottom of the second blind hole, the metal at the bottom of the third blind hole, the metal at the bottom of the fourth blind hole, the metal at the bottom of the fifth blind hole, and the metal at the bottom of the sixth blind hole; A fourth metal layer is prepared for covering the bottom of the first blind hole to obtain a second conductive pad, a fifth metal layer is prepared for covering the bottom of the second blind hole to obtain a first thermal conductive pad, a sixth metal layer is prepared for covering the bottom of the third blind hole to obtain a second thermal conductive pad, a seventh metal layer is prepared for covering the bottom of the fourth blind hole to obtain a third thermal conductive pad, an eighth metal layer is prepared for covering the bottom of the fifth blind hole to obtain a fourth thermal conductive pad, and a ninth metal layer is prepared for covering the bottom of the sixth blind hole to obtain a first conductive pad; A sixth through hole extending to the first local electrode layer is defined on the support substrate, the first conductive pad fills the sixth through hole and extends outside the support substrate, a first through hole extending to the second local electrode layer is defined on the support substrate, the second conductive pad fills the first through hole and extends outside the support substrate; A sixth through hole extending to the first local electrode layer is opened on the supporting substrate, the first local electrode layer is exposed at the bottom of the sixth through hole, metal is deposited in the sixth through hole, and the deposited metal extends outside the supporting substrate. The metal deposited in the sixth through hole and the metal extending outside the supporting substrate are the first conductive pad; a first through hole extending to the second local electrode layer is opened on the supporting substrate, the second local electrode layer is exposed at the bottom of the first through hole, metal is deposited in the first through hole, and the deposited metal extends outside the supporting substrate. The metal deposited in the first through hole and the metal extending outside the supporting substrate are the second conductive pad.

9. A thin film bulk acoustic wave filter, characterized in that: A thin film bulk acoustic resonator with good heat dissipation comprising the thin film bulk acoustic resonator according to any one of claims 1 to 7.

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