Bulk acoustic wave resonator assembly with acoustic decoupling layer, manufacturing method, filter and electronic device

Abstract

The present application relates to a bulk acoustic wave resonator assembly, comprising: a substrate; at least two resonators, the at least two resonators being bulk acoustic wave resonators and stacked in a thickness direction of the substrate on one side of the substrate, the at least two resonators comprising a first resonator and a second resonator, the second resonator being above the first resonator, the first resonator having a first top electrode, a first piezoelectric layer, a first bottom electrode and a first acoustic mirror, the second resonator having a second top electrode, a second piezoelectric layer, a second bottom electrode and a second acoustic mirror, wherein: an acoustic decoupling layer in the form of a cavity is provided between the first top electrode and the second bottom electrode, the acoustic decoupling layer acting as the second acoustic mirror. The present application also relates to a manufacturing method of a bulk acoustic wave resonator assembly, a filter and an electronic device.

Description

Technical Field

[0001] Embodiments of the present invention relate to the semiconductor field, and more particularly to a bulk acoustic wave resonator assembly and a method for manufacturing the same, a filter having the resonator assembly, and an electronic device. Background Technology

[0002] With the rapid development of wireless communication technology, the application of miniaturized portable terminal devices is becoming increasingly widespread, leading to a growing demand for high-performance, small-size radio frequency front-end modules and devices. In recent years, filter devices such as filters and duplexers based on thin-film acoustic resonators (FBARs) have become increasingly popular in the market. This is due to their excellent electrical performance, including low insertion loss, steep transition characteristics, high selectivity, high power capacity, and strong electrostatic discharge (ESD) resistance; and also to their small size and ease of integration.

[0003] However, in reality, there is a need to further reduce the size of filtering devices.

[0004] Furthermore, in existing designs, bulk acoustic wave resonators are combined in series and parallel to form filters. This requires multiple resonators to be formed on a substrate, with each resonator located at a different horizontal position on the substrate and connected by horizontal metal leads, such as... Figure 1 As shown, the dotted box indicates that the top electrode 104 of the resonator 100 is connected to the bottom electrode 102 of the resonator 200 through a conductive via 10. To ensure signal transmission and meet manufacturing process limitations, the connection width between the conductive via 10 and the top electrode 104 of the resonator 100, the width of the conductive via 10, the width of the top electrode 104 of the resonator 100, and the width of the bottom electrode 102 of the resonator 200 all have certain requirements. Generally, the total length is >5μm. This leads to the introduction of large electrical losses by the connection line, especially for high-frequency resonators. When the electrode thickness is <1000A, the insertion loss will deteriorate by more than 0.1dB. Summary of the Invention

[0005] The present invention is proposed to alleviate or solve at least one of the above-mentioned problems in the prior art.

[0006] According to one aspect of an embodiment of the present invention, a bulk acoustic resonator assembly is provided, comprising:

[0007] Base;

[0008] At least two resonators, which are bulk acoustic wave resonators, are stacked on one side of a substrate in the thickness direction of the substrate. The at least two resonators include a first resonator and a second resonator, with the second resonator above the first resonator. The first resonator has a first top electrode, a first piezoelectric layer, a first bottom electrode, and a first acoustic mirror. The second resonator has a second top electrode, a second piezoelectric layer, a second bottom electrode, and a second acoustic mirror.

[0009] in:

[0010] An acoustic decoupling layer in the form of a cavity is provided between the first top electrode and the second bottom electrode, and the acoustic decoupling layer serves as the second acoustic mirror.

[0011] Embodiments of the present invention also relate to a bulk acoustic resonator assembly, comprising at least two resonators stacked adjacent to each other from bottom to top in the thickness direction of the assembly, wherein the at least two resonators are bulk acoustic resonators, and the at least two resonators include a first resonator and a second resonator, wherein a cavity-shaped acoustic decoupling layer is disposed between the top electrode of the first resonator and the bottom electrode of the second resonator, and the acoustic decoupling layer serves as an acoustic mirror of the second resonator.

[0012] Embodiments of the present invention also relate to a method for manufacturing a bulk acoustic resonator assembly, comprising:

[0013] Step 1: Form a first structure for a first bulk acoustic resonator on the surface of a substrate, the first bulk acoustic resonator including a first acoustic mirror, a first bottom electrode, a first piezoelectric layer, and a first top electrode;

[0014] Step 2: Set a patterned sacrificial material layer on the first structure formed in Step 1;

[0015] Step 3: Form a second structure for a second bulk acoustic resonator on the structure of step 2. The second bulk acoustic resonator includes a second acoustic mirror, a second bottom electrode, a second piezoelectric layer, and a second top electrode. The sacrificial material layer is located between the first top electrode and the second bottom electrode in the thickness direction of the substrate.

[0016] Step 4: Release the sacrificial material layer to form a cavity, which constitutes the second acoustic mirror of the second bulk acoustic resonator.

[0017] Embodiments of the present invention also relate to a filter, including the aforementioned bulk acoustic resonator assembly.

[0018] Embodiments of the present invention also relate to an electronic device, including the filter or the resonator assembly described above. Attached Figure Description

[0019] The following description and accompanying drawings will better aid in understanding these and other features and advantages of the various embodiments disclosed herein, wherein the same reference numerals in the drawings always denote the same parts, wherein:

[0020] Figure 1 A schematic cross-sectional view of the electrical connection between two adjacent bulk acoustic resonators in an existing design;

[0021] Figure 2 A schematic top view of a bulk acoustic resonator assembly according to an exemplary embodiment of the present invention;

[0022] Figure 3A For an exemplary embodiment of the present invention, along Figure 2 A schematic cross-sectional view of a bulk acoustic resonator intercepted by line A-A' in the diagram;

[0023] Figure 3B For an exemplary embodiment of the present invention, along Figure 2 A schematic cross-sectional view of a bulk acoustic resonator intercepted by the B-B' line;

[0024] Figure 3C For an exemplary embodiment of the present invention, along Figure 2 A schematic cross-sectional view of a bulk acoustic resonator intercepted by the C-C' line;

[0025] Figure 3D For illustrative purposes only Figure 3A The structure relative to Figure 1 A comparison of insertion loss curves for the structures;

[0026] Figure 3E-3G According to different embodiments of the present invention, along Figure 2 A schematic cross-sectional view of a bulk acoustic resonator taken by line A-A', showing that the electrodes defining the common cavity have a shape that bulges outward relative to the common cavity;

[0027] Figure 4A For an exemplary embodiment of the present invention, along Figure 2 A schematic cross-sectional view of a bulk acoustic resonator intercepted by line A-A', wherein a portion of the non-electrode connection terminal of the bottom electrode of the upper resonator is electrically connected to the non-electrode connection terminal of the top electrode of the lower resonator in the circumferential direction.

[0028] Figure 4B For an exemplary embodiment of the present invention, along Figure 2 A schematic cross-sectional view of a bulk acoustic resonator intercepted by the B-B' line, wherein the electrode connection terminal of the bottom electrode of the upper resonator is electrically connected to the electrode connection terminal of the top electrode of the lower resonator.

[0029] Figure 5AFor an exemplary embodiment of the present invention, along Figure 2 The schematic cross-sectional view of the bulk acoustic resonator obtained by the A-A' line is shown in the figure. The non-electrode connection end of the bottom electrode of the upper resonator is not electrically connected to the non-electrode connection end of the top electrode of the lower resonator. The end of the non-electrode connection end of the bottom electrode of the upper resonator is located on the upper surface of the piezoelectric layer of the lower resonator.

[0030] Figure 5B For an exemplary embodiment of the present invention, along Figure 2 The schematic cross-sectional view of the bulk acoustic resonator obtained by the A-A' line is shown in the figure. The non-electrode connection end of the bottom electrode of the upper resonator is not electrically connected to the non-electrode connection end of the top electrode of the lower resonator. A part of the end of the non-electrode connection end of the bottom electrode of the upper resonator is located on the upper surface of the piezoelectric layer of the lower resonator, while the other part of the end is located inside the boundary of the common cavity in the lateral direction.

[0031] Figure 5C For an exemplary embodiment of the present invention, along Figure 2 A schematic cross-sectional view of a bulk acoustic resonator intercepted by the C-C' line;

[0032] Figures 6A-6C A cross-sectional schematic diagram of a bulk acoustic resonator assembly according to different embodiments of the present invention is shown, in which a cavity is formed between the bottom electrode of the upper resonator and the top electrode of the lower resonator and a support member is provided.

[0033] Figures 7A-7E An example is shown Figure 3A A schematic diagram illustrating the fabrication process of the structure shown.

[0034] Figure 8A and 8B An example shows the production Figures 6A-6C A schematic diagram of the structure of the support component method in the process;

[0035] Figure 9 A schematic cross-sectional view of a bulk acoustic resonator assembly according to an exemplary embodiment of the present invention;

[0036] Figure 10 This is a cross-sectional view of a resonator assembly according to an exemplary embodiment of the present invention, wherein the effective regions of the upper and lower resonators are acoustically isolated by cavities, and Figure 10 In the left-hand view, the upper and lower resonators are electrically isolated from each other. Figure 10 In the right-side view, the upper and lower resonators are electrically connected to each other. Detailed Implementation

[0037] The technical solution of the present invention will be further described in detail below through embodiments and in conjunction with the accompanying drawings. In this specification, the same or similar reference numerals indicate the same or similar components. The following description of the embodiments of the present invention with reference to the accompanying drawings is intended to explain the overall inventive concept of the present invention and should not be construed as a limitation thereof. These are only some embodiments of the invention, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention are within the scope of protection of the present invention.

[0038] The reference numerals in the drawings of this invention are explained as follows:

[0039] 11: The bottom electrode of the lower resonator has external leads.

[0040] 12: The top electrode of the lower resonator has external leads.

[0041] 13: The bottom electrode of the upper resonator has external leads.

[0042] 14: External leads of the top electrode of the upper resonator. The external leads 11-14 of the above electrodes are connected to the corresponding electrodes.

[0043] S: Substrate, with optional materials including single-crystal silicon, gallium nitride, gallium arsenide, sapphire, quartz, silicon carbide, diamond, etc.

[0044] 101, 201: Acoustic mirrors. Acoustic mirror 101 can be a cavity, or it can be a Bragg reflector layer or other equivalent forms. Acoustic mirror 201 is a cavity, which constitutes an acoustic decoupling layer.

[0045] 102,202: Bottom electrode, materials can be selected from molybdenum, ruthenium, gold, aluminum, magnesium, tungsten, copper, titanium, iridium, osmium, chromium or composites or alloys of the above metals, etc.

[0046] 103, 203: Piezoelectric layer, which can be a single-crystal piezoelectric material, such as single-crystal aluminum nitride, single-crystal gallium nitride, single-crystal lithium niobate, single-crystal lead zirconate titanate (PZT), single-crystal potassium niobate, single-crystal quartz film, or single-crystal lithium tantalate, etc. It can also be a polycrystalline piezoelectric material (as opposed to single-crystal, a non-single-crystal material), such as polycrystalline aluminum nitride, zinc oxide, PZT, etc. It can also be a rare earth element containing a certain atomic ratio of the above materials. The doped material can be, for example, doped aluminum nitride, which contains at least one rare earth element, such as scandium (Sc), yttrium (Y), magnesium (Mg), titanium (Ti), lanthanum (La), cerium (Ce), praseodymium (Pr), neodymium (Nd), promethium (Pm), samarium (Sm), europium (Eu), gadolinium (Gd), terbium (Tb), dysprosium (Dy), holmium (Ho), erbium (Er), thulium (Tm), ytterbium (Yb), lutetium (Lu), etc.

[0047] 104, 204: Top electrode, whose material can be the same as the bottom electrode. Materials can include molybdenum, ruthenium, gold, aluminum, magnesium, tungsten, copper, titanium, iridium, osmium, chromium, or composites or alloys of the above metals. The top and bottom electrodes are generally made of the same material, but they can also be different.

[0048] 105, 205: Passivation layer, generally a dielectric material, such as silicon dioxide, aluminum nitride, silicon nitride, etc.

[0049] Figure 2 This is a schematic top view of a bulk acoustic resonator assembly according to an exemplary embodiment of the present invention. Figure 2 In the diagram, line A-A' corresponds to the cross-section through the non-electrode connection terminals of the top and bottom electrodes of the upper and lower resonators, line B-B' corresponds to the cross-section through the electrode connection terminals of the bottom and top electrodes of the lower resonator, and line C-C' corresponds to the cross-section through the electrode connection terminals of the bottom and top electrodes of the upper resonator.

[0050] Figure 3A For an exemplary embodiment of the present invention, along Figure 2 A schematic cross-sectional view of a bulk acoustic resonator obtained by the A-A' line.

[0051] Although not shown, a process layer can also be disposed on the top electrode of the resonator. This process layer can cover the top electrode and can function as a mass conditioning load or a passivation layer. The passivation layer can be made of a dielectric material, such as silicon dioxide, aluminum nitride, or silicon nitride.

[0052] In addition, Figure 3A In the structure shown, two resonators are formed at the same horizontal position on the substrate S, and the two resonators are spatially different in the vertical direction or in the thickness direction of the substrate.

[0053] As those skilled in the art will understand, three or more resonators may be stacked. Figure 9 This is a schematic cross-sectional view of a bulk acoustic resonator assembly according to an exemplary embodiment of the present invention. Figure 9 As shown, the resonator assembly includes a first resonator, a second resonator, and a third resonator stacked in the thickness direction. An acoustic decoupling layer 201 (a cavity in this embodiment) is provided between the top electrode 104 of the first resonator and the bottom electrode 202 of the second resonator. An acoustic decoupling layer 301 (a cavity in this embodiment) is also provided between the top electrode 204 of the second resonator and the bottom electrode 302 of the third resonator. The acoustic decoupling layer 301 constitutes the acoustic mirror of the third resonator. Optionally, such as... Figure 9As shown, the boundary of the acoustic decoupling layer 301 is located outside the boundary of the acoustic decoupling layer 201 in the horizontal direction. It will be understood that the component structures shown in other embodiments of the invention may also be stacked.

[0054] exist Figure 3A The structure shown includes two resonators, an upper and a lower one. The effective region of the upper resonator is the overlapping area in the thickness direction of the top electrode 204, the piezoelectric layer 203, the bottom electrode 202, and the cavity 201. The lower resonator is the overlapping area in the thickness direction of the cavity 201, the top electrode 104, the piezoelectric layer 103, the bottom electrode 102, and the acoustic mirror 101.

[0055] Correspondingly, in Figure 9 In the middle, the effective region of the uppermost third resonator is the overlapping region of the top electrode 304, piezoelectric layer 303, bottom electrode 302, and cavity 301 in the thickness direction; the effective region of the middle second resonator is the overlapping region of the cavity 301, top electrode 204, piezoelectric layer 203, bottom electrode 202, and cavity 201 in the thickness direction; and the effective region of the lowermost first resonator is the overlapping region of the cavity 201, top electrode 104, piezoelectric layer 103, bottom electrode 102, and cavity 101 in the thickness direction.

[0056] exist Figure 3A In the structure shown, the upper resonator and the lower resonator are acoustically separated by the cavity 201. That is, the cavity 201 constitutes an acoustic decoupling layer between the upper and lower resonators, thereby completely avoiding the acoustic coupling problem that may be caused by the adjacent stacking of the two resonators.

[0057] Using cavity 201 as an acoustic decoupling layer enables complete acoustic decoupling of the upper and lower resonators, resulting in superior resonator performance. Furthermore, cavity 201 is directly surrounded by the top electrode 104 of the lower resonator and the bottom electrode 202 of the upper resonator (in other embodiments, the structure defining the cavity location also includes the piezoelectric layer of the upper and / or lower resonator), for example... Figures 3A-3C In the case of the structures shown in 3E-3G and 9, the overall structure is stable and reliable and the processing technology is simple.

[0058] As those skilled in the art will understand, the cavity 201 disposed between the bottom electrode of the upper resonator and the top electrode of the lower resonator in the thickness direction of the resonator includes not only the case where at least a portion of the upper and lower boundaries of the cavity is defined by the lower surface of the bottom electrode of the upper resonator and the upper surface of the top electrode of the lower resonator, but also the case where a process layer (e.g., a passivation layer) is disposed on the upper surface of the top electrode of the lower resonator, thereby defining at least a portion of the lower boundary of the cavity 201. All of these are within the scope of protection of this invention.

[0059] exist Figure 3A In the structure shown, because multiple resonators are formed at the same horizontal position on the substrate S, and the spatial positions of these resonators differ in the vertical direction or in the thickness direction of the substrate, the area of ​​the filter can be greatly reduced. For example, with the same arrangement of two resonators, the area can be reduced from... Figure 1 The area P1 shown is reduced to Figure 3A The area P2 shown is shown.

[0060] like Figure 3A As shown, the bottom electrode 202 of the upper resonator and the top electrode 104 of the lower resonator are electrically connected to each other at the non-electrode connection terminals. When the bottom electrode of the upper resonator is directly connected to the top electrode of the lower resonator, the bottom electrode of the upper resonator and the top electrode of the lower resonator are directly electrically connected, and the length of the connection portion is relatively... Figure 1 The intermediate frequency is shortened, meaning the transmission path is shortened, reducing transmission loss. Furthermore, the electrical signal output passes through a metal with a thickness equal to the sum of the thicknesses of the top electrode of the lower resonator and the bottom electrode of the upper resonator, further reducing transmission loss. By reducing electrical loss, the insertion loss of the final filter is optimized. For example... Figure 3A As shown, the length of the transmission path formed by the bottom electrode of the upper resonator and the top electrode of the lower resonator at the non-connected end of the electrodes is d, which can be less than 5μm.

[0061] Using the structure shown in Figures 3A-3C, the current transmission path to the lower resonator is shortened, for example, to less than 5 μm, reducing transmission loss. This allows for thinner top electrode 104 of the lower resonator and bottom electrode 202 of the upper resonator, facilitating further miniaturization of the resonator. With the bottom electrode of the upper resonator and the top electrode of the lower resonator electrically connected, the circuit transmission path loss to the bottom electrode of the upper resonator and the current transmission path loss to the top electrode of the lower resonator can be reduced, while simultaneously decreasing the electrode film thickness of both the bottom and top electrodes of the upper resonator. Correspondingly, when the resonant frequency of the lower resonator is greater than 0.5 GHz, the thickness of the top electrode 104 is less than... And / or, when the resonant frequency of the upper resonator is greater than 0.5 GHz, the thickness of the bottom electrode 202 is less than In a further embodiment, when the resonant frequency of the lower resonator is greater than 3 GHz, the thickness of the top electrode 104 can be designed to be less than [the required thickness]. And / or, when the resonant frequency of the upper resonator is greater than 3 GHz, the thickness of the bottom electrode 202 of the upper resonator can also be less than [a certain value]. As will be understood, in this invention, the thinning of the electrode thickness refers to the thinning of the portion of the electrode within the effective region of the resonator.

[0062] Figure 3D For illustrative purposes only Figure 3A The structure relative to Figure 1 A comparison of insertion loss curves for the structures. Figure 3D This invention is used in the 3.5G frequency band. Figure 3A The insertion loss curve (solid line) after the structure is compared with that after using Figure 1 A comparison of the insertion loss curve (dashed line) of the traditional structure shows that the method using the present invention... Figure 3A After the structure is completed, the insertion loss is improved by approximately 0.1 dB due to the reduction in electrode loss.

[0063] Figure 3B For an exemplary embodiment of the present invention, along Figure 2 A schematic cross-sectional view of a bulk acoustic resonator intercepted by the B-B' line. Figure 3C For an exemplary embodiment of the present invention, along Figure 2 A schematic cross-sectional view of the bulk acoustic resonator intercepted by the C-C' line. It can be seen that, in... Figure 3B and 3C In the middle, the top electrode of the lower resonator and the bottom electrode of the upper resonator are electrically connected in the circumferential direction around the entire cavity 201.

[0064] When the bottom electrode of the upper resonator and the top electrode of the lower resonator are electrically connected to each other, Figures 3A-3C In the structure shown, the bottom electrode of the upper resonator and the non-electrode connection terminals and electrode connection terminals of the top electrode of the lower resonator are all connected to each other, forming an electrical connection around the entire circumference of the cavity 201. However, besides... Figures 3A-3C Besides the connection method shown, other connection methods are also possible. For example, see below. Figure 4A As described above, the bottom electrode of the upper resonator and the top electrode of the lower resonator may be electrically connected to each other only at some of the non-electrode connection terminals; or, as shown in the appendix... Figure 4B The bottom electrode of the upper resonator and the top electrode of the lower resonator may be electrically connected to each other only at the electrode connection terminals; or the bottom electrode of the upper resonator and the top electrode of the lower resonator may be electrically connected to each other only at all or part of the non-electrode connection terminals. These are all within the scope of protection of this invention.

[0065] The connection between the bottom electrode of the upper resonator and the top electrode of the lower resonator is not limited to... Figures 3A-3C The structure shown. Figure 10 This is a cross-sectional view of a resonator assembly according to an exemplary embodiment of the present invention, wherein the effective regions of the upper and lower resonators are acoustically isolated by a cavity. Figure 10 In the right-side view, the upper and lower resonators are electrically connected to each other.

[0066] like Figure 10As shown in the right-hand cross-sectional view, the top electrode 104 is covered by a piezoelectric layer 103, and the bottom electrode 202 is connected to the top electrode 104 at both the electrode connection end and the non-electrode connection end. Figure 10 In the right-side view, the electrode connection end of the bottom electrode 202 covers the electrode connection end of the top electrode 104, and the non-electrode connection end of the bottom electrode 202 covers the non-electrode connection end of the top electrode 104.

[0067] exist Figure 10 The diagram shows process layers or passivation layers 105 and 205 disposed on the upper surface of the top electrode, which may or may not be disposed.

[0068] In this invention Figure 10 In the structure shown, since the second electrode layer where the bottom electrode 202 is located covers the first electrode layer where the top electrode 104 is located, the metal thickness of the bottom electrode of the upper resonator and the top electrode of the lower resonator at the electrode connection part can be increased, which is beneficial to reduce electrical losses.

[0069] When the ratio of the maximum effective width of the resonator to the cavity height is large, the upper and lower resonators may come into contact within the cavity due to bending or other reasons. For example, if the cavity height is... When the maximum width of the effective region of the resonator is greater than 100μm, in order to ensure the complete formation of the cavity 201 within the effective regions of the upper and lower resonators, the stress of the lower resonator can be controlled to bend it downwards towards the air cavity, and / or the stress of the upper resonator can be controlled to bend it upwards towards the air cavity. The top electrode of the lower resonator is concave downwards, and / or the top electrode of the upper resonator is convex upwards. Figure 3E-3G According to different embodiments of the present invention, along Figure 2 A schematic cross-sectional view of the bulk acoustic resonator taken along line A-A', showing that the electrodes defining cavity 201 have a shape that bulges outward relative to the common cavity. Specifically, Figure 3E This is a schematic diagram of the lower resonator bending downwards. Figure 3F This is a schematic diagram of the upper resonator bending upwards. Figure 3G This diagram illustrates a lower resonator bent downwards and an upper resonator bent upwards. On the other hand, although adjusting the stress of the thin films of the upper and lower resonators to cause them to bend can prevent contact, the stress of the upper resonator film will affect the operating state and performance of the lower resonator to some extent, and vice versa, due to the small thickness of the upper and lower resonator films and the mechanical contact between the upper and lower resonators at the edge of the acoustic decoupling layer in the cavity form. Therefore, the lower the stress of the lower resonator film, the better (i.e., the film should not bend, such as...). Figures 3A-3C In this way, the two resonators do not affect each other's performance; of course, to prevent the upper and lower resonators from contacting each other due to bending or other reasons within the cavity, it is necessary to adjust the stress (e.g.) Figure 3E-3G To sacrifice some of the resonator's performance, thus ensuring that the two do not come into contact.

[0070] Figure 4A For an exemplary embodiment of the present invention, along Figure 2 A schematic cross-sectional view of a bulk acoustic resonator intercepted by line A-A'. Figure 4A In the middle, a portion of the non-electrode connection terminal of the bottom electrode 202 of the upper resonator is electrically connected to the top electrode 104 of the lower resonator in the circumferential direction. Figure 4A (As shown on the right side of the image), and the other part of the non-electrode connection terminal of the bottom electrode 202 of the upper resonator in the circumferential direction is not electrically connected to the top electrode 104 of the lower resonator, and this other part is located outside the non-electrode connection terminal of the top electrode 104 in the lateral direction and is disposed on the upper surface of the piezoelectric layer 103 of the lower resonator. Figure 4A (As shown on the left side of the image).

[0071] Figure 4B For an exemplary embodiment of the present invention, along Figure 2 A schematic cross-sectional view of a bulk acoustic resonator intercepted by the B-B' line. Figure 4B In the upper resonator, the bottom electrode of the upper resonator is electrically connected to the top electrode of the lower resonator. However, the non-electrode connection terminals of the bottom electrode of the upper resonator and the top electrode of the lower resonator are not connected to each other.

[0072] In the above embodiments, the bottom electrode of the upper resonator and the top electrode of the lower resonator are electrically connected to each other, but the present invention is not limited thereto. When two stacked bulk acoustic resonators share an acoustic decoupling layer, the bottom electrode of the upper resonator and the top electrode of the lower resonator can also be electrically isolated from each other.

[0073] Figure 5A For an exemplary embodiment of the present invention, along Figure 2 A schematic cross-sectional view of a bulk acoustic resonator intercepted by line A-A'. Figure 5A In the middle, the bottom electrode 202 of the upper resonator and the top electrode 104 of the lower resonator are not electrically connected. The non-electrode connection end of the bottom electrode 202 of the upper resonator is located outside the top electrode 104 of the lower resonator and is located on the upper surface of the piezoelectric layer 103 of the lower resonator.

[0074] Figure 5B For an exemplary embodiment of the present invention, along Figure 2The schematic cross-sectional view of the bulk acoustic resonator taken by line A-A' shows that the non-electrode connection terminal of the bottom electrode 202 of the upper resonator is not electrically connected to the non-electrode connection terminal of the top electrode 104 of the lower resonator. A portion of the end of the non-electrode connection terminal of the bottom electrode of the upper resonator is disposed on the upper surface of the piezoelectric layer 103 of the lower resonator (see Figure 103). Figure 5B (Left side of the image) while the other end is located inside the boundary of the shared cavity in the lateral direction (see image). Figure 5B (The right side of the middle).

[0075] Figure 5C For an exemplary embodiment of the present invention, along Figure 2 The schematic cross-sectional view of the bulk acoustic resonator obtained by the C-C' line is shown in the figure. The non-electrode connection terminal of the bottom electrode 202 of the upper resonator is not electrically connected to the non-electrode connection terminal of the top electrode 104 of the lower resonator, and the electrode connection terminal of the bottom electrode 202 of the upper resonator is not electrically connected to the electrode connection terminal of the top electrode 104 of the lower resonator.

[0076] Figure 10 This is a cross-sectional view of a resonator assembly according to an exemplary embodiment of the present invention, wherein the effective regions of the upper and lower resonators are acoustically isolated by cavities, and Figure 10 In the left-hand view, the upper and lower resonators are electrically isolated from each other.

[0077] exist Figure 10 In the left-hand view, the top electrode 104 is located in the first electrode layer. Figure 10 In the left-hand view, the aforementioned first electrode layer includes a top electrode 104 and a non-top electrode layer located outside the non-electrode connection terminal of the top electrode 104 via a disconnect structure 106. Figure 10 (The left side of the broken structure 106). Figure 10 In the middle, the bottom electrode 202 is located in the second electrode layer, such as Figure 10 As shown in the left-hand view, the second electrode layer includes a bottom electrode 202 and a non-bottom electrode layer located outside the non-electrode connection terminal of the bottom electrode 202, electrically isolated from the non-electrode connection terminal of the bottom electrode 202 via a disconnection structure 206. Figure 10 (The right side of the disconnected structure 206). Figure 10 In the left-hand view, the electrode connection end of the bottom electrode 202 covers the non-top electrode layer, and the non-bottom electrode layer covers the electrode connection end of the top electrode 104.

[0078] Figures 6A-6C This is a cross-sectional schematic diagram of a bulk acoustic resonator assembly according to different embodiments of the present invention, showing a cavity 201 between the bottom electrode of the upper resonator and the top electrode of the lower resonator, and a support member 401 is provided thereon.

[0079] exist Figure 3E-3G In the example shown, controlled stress can reduce the probability of the upper and lower resonators contacting each other, but when the resonator area is large, such as... Figures 6A-6C As shown, a support member 401 can be added. This support member 401 can contact the top or top electrode of the lower resonator, and the height of the support member must be less than or equal to the cavity height. "Equal" means the top of the support member contacts the bottom or bottom electrode of the upper resonator; "less than" means the top of the support member does not contact the upper resonator. Only when the cavity thickness decreases locally due to resonator bending will the top of the support member contact the upper resonator, thus providing support. Figures 6A-6C In the structure shown, the support 401 is in contact with both the bottom electrode of the upper resonator and the top electrode of the lower resonator.

[0080] The following reference Figures 7A-7E Exemplary Description Figure 3A The fabrication process of the structure shown.

[0081] First, such as Figure 7A As shown, a bottom electrode 102, a piezoelectric layer 103, and an electrode material layer for a top electrode 104 are formed on a substrate S. The upper surface of the substrate S also has a recess for forming an acoustic mirror 101, and the recess is filled with a sacrificial material. Figures 7A-7E In the diagram, passivation layers, frequency modulation layers, and other films that are not closely related to the concept of this patent are not shown.

[0082] Secondly, such as Figure 7B As shown, in Figure 7A A sacrificial material layer is deposited on the structure. To improve the quality of subsequent film growth, the deposited sacrificial material layer is then surface-treated using CMP (chemical mechanical polishing). Following this, an etching patterning process is performed on the sacrificial material layer to form a sacrificial layer 301, which is used to remove the sacrificial material in subsequent processes to form cavities 201. The sacrificial material can be polycrystalline silicon, amorphous silicon, silicon dioxide, doped silicon dioxide, or other similar materials.

[0083] Again, in Figure 7B The structure shown has an electrode metal layer deposited using sputtering or evaporation processes to form the bottom electrode 202 of the upper resonator. Next, the electrode metal layers corresponding to the bottom electrode 202 and the top electrode 104 are etched using photolithography and etching processes to form... Figure 7C The structure shown.

[0084] Again, as Figure 7D As shown, release Figure 7C The sacrificial material is used to form cavity 201 and acoustic mirror cavity 101.

[0085] Finally, Figure 7DA piezoelectric layer 203 and a top electrode 204 are formed on the structure shown. This ultimately forms... Figure 3A The structure shown is as follows: Figure 7E As shown.

[0086] It should be noted that, in the above manufacturing process, the sacrificial material can also be released after the piezoelectric layer and top electrode of the upper resonator are formed to form cavity 201 and acoustic mirror cavity 101.

[0087] Figure 8A and 8B An example shows the production Figures 6A-6C A structural diagram illustrating the method for fabricating the support components. Figure 6A Structure and manufacturing shown Figure 3A The structure shown differs in that it is manufactured... Figure 6A When the structure shown is in the above... Figure 7B Before the corresponding steps, it is necessary to Figure 7A On the structure shown, a support member 401 is fabricated, and then, on top of it... Figure 7B In the corresponding steps, a sacrificial material layer is deposited to cover the support 401. Then, the deposited sacrificial material layer is surface-treated using CMP (chemical mechanical polishing). Following this, an etching patterning process is performed on the sacrificial material layer to form a shape such as... Figure 8A The sacrificial layer 301 shown is used to remove it in a subsequent process to form the cavity 201.

[0088] exist Figure 8A In this structure, the height of the support 401 is less than the thickness of the sacrificial layer 301, so that in the final structure, the upper end of the support 401 does not contact the bottom electrode of the upper resonator. Figure 8B In this structure, the height of the support 401 is the same as the thickness of the sacrificial layer 301, so that in the final structure, the upper end of the support 401 contacts the bottom electrode of the upper resonator.

[0089] for Figure 7A The structure shown is manufactured in a manner similar to... Figure 3A The difference lies in the fabrication process of the structure. Figure 7B In the corresponding steps, the sacrificial layer is replaced with an acoustic reflective layer, and in Figure 7D In the corresponding steps, the step of removing the sacrificial layer 301 is cancelled.

[0090] It should be noted that, in this invention, each numerical range, except where explicitly stated not to include endpoint values, can be either an endpoint value or the median of each numerical range, and all of these are within the protection scope of this invention.

[0091] In this invention, "upper" and "lower" are relative to the bottom surface of the resonator's base. For a component, the side closer to the bottom surface is the lower side, and the side farther from the bottom surface is the upper side.

[0092] In this invention, "inner" and "outer" refer to the center of the effective region of the resonator (i.e., the center of the effective region) in the lateral or radial direction. The side or end of a component closer to the center of the effective region is called the inner side or inner end, while the side or end of the component farther from the center of the effective region is called the outer side or outer end. For a reference position, being inside the position means being between that position and the center of the effective region in the lateral or radial direction, while being outside the position means being farther from the center of the effective region in the lateral or radial direction than that position.

[0093] As those skilled in the art will understand, the bulk acoustic resonator according to the present invention can be used to form filters or electronic devices. These electronic devices include, but are not limited to, intermediate products such as RF front-ends and filtering / amplifying modules, as well as terminal products such as mobile phones, Wi-Fi devices, and drones.

[0094] Based on the above, the present invention proposes the following technical solution:

[0095] 1. A bulk acoustic resonator assembly, comprising:

[0096] Base;

[0097] At least two resonators, which are bulk acoustic wave resonators, are stacked on one side of a substrate in the thickness direction of the substrate. The at least two resonators include a first resonator and a second resonator, with the second resonator above the first resonator. The first resonator has a first top electrode, a first piezoelectric layer, a first bottom electrode, and a first acoustic mirror. The second resonator has a second top electrode, a second piezoelectric layer, a second bottom electrode, and a second acoustic mirror.

[0098] in:

[0099] An acoustic decoupling layer in the form of a cavity is provided between the first top electrode and the second bottom electrode, and the acoustic decoupling layer serves as the second acoustic mirror.

[0100] 2. The component according to 1, wherein:

[0101] The first top electrode and the second bottom electrode are electrically connected to each other.

[0102] 3. The component according to 2, wherein:

[0103] The end of the non-electrode connection of the first top electrode is connected to the end of the non-electrode connection of the second bottom electrode.

[0104] 4. The component according to 3, wherein:

[0105] The end of the non-electrode connection of the first top electrode and the end of the non-electrode connection of the second bottom electrode are connected to each other in the entire circumferential direction.

[0106] 5. The component according to 3, wherein:

[0107] A portion of the non-electrode connection end of the second bottom electrode is disposed on the upper surface of the first piezoelectric layer in the circumferential direction and is located outside the non-electrode connection end of the first bottom electrode in the horizontal direction.

[0108] 6. The component according to claim 2, wherein:

[0109] A conductive support is provided between the first top electrode and the second bottom electrode, and the first top electrode and the second bottom electrode are electrically connected to each other through the conductive support.

[0110] 7. The component according to 2, wherein:

[0111] The electrode connection terminal of the first top electrode is electrically connected to the electrode connection terminal of the second bottom electrode.

[0112] 8. The component according to 2, wherein:

[0113] The electrode connection terminal of the first top electrode is electrically connected to the electrode connection terminal of the second bottom electrode, and the non-electrode connection terminal of the first top electrode is electrically connected to the non-electrode connection terminal of the second bottom electrode.

[0114] 10. The component according to claim 3, wherein:

[0115] The length of the connection path between the first top electrode and the second bottom electrode at their non-connection ends is less than 5 μm.

[0116] 11. The component according to claim 1, wherein:

[0117] The first top electrode and the second bottom electrode are electrically isolated from each other.

[0118] 12. The component according to 11, wherein:

[0119] At least a portion of the non-electrode connection end of the second bottom electrode in the circumferential direction or the end of the electrode connection end of the second bottom electrode is disposed on the upper surface of the first piezoelectric layer, and the end is located outside the non-electrode connection end of the first top electrode in the horizontal direction.

[0120] 13. The component according to 12, wherein:

[0121] A portion of the non-electrode connection end of the second bottom electrode in the circumferential direction or the end of the electrode connection end of the second bottom electrode is disposed on the upper surface of the first piezoelectric layer, and the other portion of the non-electrode connection end of the second bottom electrode in the circumferential direction is located inside the boundary of the acoustic decoupling layer in the horizontal direction.

[0122] 14. The component according to 13, wherein:

[0123] The component includes a first electrode layer and a second electrode layer;

[0124] The first electrode layer includes a first top electrode and a non-top electrode layer that is electrically isolated from the non-electrode connection terminal of the first top electrode and located outside the non-electrode connection terminal of the first top electrode;

[0125] The second electrode layer includes a second bottom electrode and a non-bottom electrode layer that is electrically isolated from the non-electrode connection terminal of the second bottom electrode and located outside the non-electrode connection terminal of the second bottom electrode;

[0126] The electrode connection end of the second bottom electrode covers the non-top electrode layer, and the non-bottom electrode layer covers the electrode connection end of the first top electrode.

[0127] 15. The component according to claim 1, wherein:

[0128] At least one of the first top electrode and the second bottom electrode has a convex shape that protrudes away from the cavity; or

[0129] The portion of the first top electrode defining the lower side of the cavity and the portion of the second bottom electrode defining the upper side of the cavity both have a flat shape.

[0130] 16. The component according to 15, wherein:

[0131] The component has a support member between the first top electrode and the second bottom electrode.

[0132] 17. The component according to claim 2, wherein:

[0133] The resonant frequency of the lower resonator is greater than 0.5 GHz, and the thickness of the first top electrode is less than... and / or

[0134] The resonant frequency of the upper resonator is greater than 0.5 GHz, and the thickness of the second bottom electrode is less than...

[0135] 18. The component according to 17, wherein:

[0136] The resonant frequency of the lower resonator is greater than 3GHz, and the thickness of the first top electrode is less than... and / or

[0137] The resonant frequency of the upper resonator is greater than 3GHz, and the thickness of the second bottom electrode is less than...

[0138] 19. A bulk acoustic resonator assembly, comprising:

[0139] At least two resonators are stacked adjacent to each other from bottom to top in the thickness direction of the component. The at least two resonators are bulk acoustic resonators. The at least two resonators include a first resonator and a second resonator. An acoustic decoupling layer in the form of a cavity is provided between the top electrode of the first resonator and the bottom electrode of the second resonator. The acoustic decoupling layer serves as an acoustic mirror of the second resonator.

[0140] 20. The component according to 1 or 19, wherein:

[0141] The at least two resonators include a first resonator, a second resonator, and a third resonator stacked in the thickness direction;

[0142] The first acoustic decoupling layer is located between the top electrode of the first resonator and the bottom electrode of the second resonator, and the second acoustic decoupling layer is located between the top electrode of the second resonator and the bottom electrode of the third resonator in the form of a cavity. The second acoustic decoupling layer constitutes the acoustic mirror of the third resonator.

[0143] 21. The component according to 20, wherein:

[0144] The boundary of the second acoustic decoupling layer is located outside the boundary of the first acoustic decoupling layer in the horizontal direction.

[0145] 22. A method for manufacturing a bulk acoustic resonator assembly, comprising:

[0146] Step 1: Form a first structure for a first bulk acoustic resonator on the surface of a substrate, the first bulk acoustic resonator including a first acoustic mirror, a first bottom electrode, a first piezoelectric layer, and a first top electrode;

[0147] Step 2: Set a patterned sacrificial material layer on the first structure formed in Step 1;

[0148] Step 3: Form a second structure for a second bulk acoustic resonator on the structure of step 2. The second bulk acoustic resonator includes a second acoustic mirror, a second bottom electrode, a second piezoelectric layer, and a second top electrode. The sacrificial material layer is located between the first top electrode and the second bottom electrode in the thickness direction of the substrate.

[0149] Step 4: Release the sacrificial material layer to form a cavity, which constitutes the second acoustic mirror of the second bulk acoustic resonator.

[0150] 23. According to the method described in 22, wherein:

[0151] Step 2 also includes providing supports in the sacrificial material layer.

[0152] 24. A filter comprising a bulk acoustic resonator assembly according to any one of 1-21.

[0153] 25. An electronic device comprising the filter according to claim 24 or the bulk acoustic resonator assembly according to any one of claims 1-21.

[0154] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that variations may be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A bulk acoustic resonator assembly, comprising: Base; The system comprises at least two resonators, which are bulk acoustic wave resonators stacked on one side of a substrate in the thickness direction of the substrate. The at least two resonators include a first resonator and a second resonator, with the second resonator positioned above the first resonator. The first resonator has a first top electrode, a first piezoelectric layer, a first bottom electrode, and a first acoustic mirror. The second resonator has a second top electrode, a second piezoelectric layer, a second bottom electrode, and a second acoustic mirror. in: An acoustic decoupling layer in the form of a cavity is provided between the first top electrode and the second bottom electrode. The acoustic decoupling layer serves as the second acoustic mirror. The cavity is formed based on the support of the second bottom electrode in the thickness direction. At least a portion of the cavity is located in the thickness direction between the effective region of the first resonator and the effective region of the second resonator.

2. The component according to claim 1, wherein: The first top electrode and the second bottom electrode are electrically connected to each other.

3. The component according to claim 2, wherein: The end of the non-electrode connection of the first top electrode is connected to the end of the non-electrode connection of the second bottom electrode.

4. The component according to claim 3, wherein: The end of the non-electrode connection of the first top electrode and the end of the non-electrode connection of the second bottom electrode are connected to each other in the entire circumferential direction.

5. The component according to claim 3, wherein: A portion of the non-electrode connection end of the second bottom electrode is disposed on the upper surface of the first piezoelectric layer in the circumferential direction and is located outside the non-electrode connection end of the first bottom electrode in the horizontal direction.

6. The component according to claim 2, wherein: A conductive support is provided between the first top electrode and the second bottom electrode, and the first top electrode and the second bottom electrode are electrically connected to each other through the conductive support.

7. The component according to claim 2, wherein: The electrode connection terminal of the first top electrode is electrically connected to the electrode connection terminal of the second bottom electrode.

8. The component according to claim 2, wherein: The electrode connection terminal of the first top electrode is electrically connected to the electrode connection terminal of the second bottom electrode, and the non-electrode connection terminal of the first top electrode is electrically connected to the non-electrode connection terminal of the second bottom electrode.

9. The component according to claim 3, wherein: The length of the connection path between the first top electrode and the second bottom electrode at their non-connection ends is less than 5 μm.

10. The component of claim 1, wherein: The first top electrode and the second bottom electrode are electrically isolated from each other.

11. The component of claim 10, wherein: At least a portion of the non-electrode connection end of the second bottom electrode in the circumferential direction or the end of the electrode connection end of the second bottom electrode is disposed on the upper surface of the first piezoelectric layer, and the end is located outside the non-electrode connection end of the first top electrode in the horizontal direction.

12. The component of claim 11, wherein: A portion of the non-electrode connection end of the second bottom electrode in the circumferential direction or the end of the electrode connection end of the second bottom electrode is disposed on the upper surface of the first piezoelectric layer, and the other portion of the non-electrode connection end of the second bottom electrode in the circumferential direction is located inside the boundary of the acoustic decoupling layer in the horizontal direction.

13. The component of claim 12, wherein: The component includes a first electrode layer and a second electrode layer; The first electrode layer includes a first top electrode and a non-top electrode layer that is electrically isolated from the non-electrode connection terminal of the first top electrode and located outside the non-electrode connection terminal of the first top electrode; The second electrode layer includes a second bottom electrode and a non-bottom electrode layer that is electrically isolated from the non-electrode connection terminal of the second bottom electrode and located outside the non-electrode connection terminal of the second bottom electrode; The electrode connection end of the second bottom electrode covers the non-top electrode layer, and the non-bottom electrode layer covers the electrode connection end of the first top electrode.

14. The component of claim 1, wherein: At least one of the first top electrode and the second bottom electrode has a convex shape that protrudes away from the cavity; or The portion of the first top electrode defining the lower side of the cavity and the portion of the second bottom electrode defining the upper side of the cavity both have a flat shape.

15. The component of claim 14, wherein: The component has a support member between the first top electrode and the second bottom electrode.

16. The component of claim 2, wherein: The resonant frequency of the first resonator is greater than 0.5 GHz, and the thickness of the first top electrode is less than 5000 Å; and / or The resonant frequency of the second resonator is greater than 0.5 GHz, and the thickness of the second bottom electrode is less than 5000 Å.

17. The component of claim 16, wherein: The resonant frequency of the first resonator is greater than 3 GHz, and the thickness of the first top electrode is less than 2000 Å; and / or The resonant frequency of the second resonator is greater than 3 GHz, and the thickness of the second bottom electrode is less than 2000 Å.

18. A bulk acoustic resonator assembly, comprising: At least two resonators are stacked adjacent to each other from bottom to top in the thickness direction of the component. The at least two resonators are bulk acoustic resonators. The at least two resonators include a first resonator and a second resonator. An acoustic decoupling layer in the form of a cavity is provided between the top electrode of the first resonator and the bottom electrode of the second resonator. The acoustic decoupling layer serves as an acoustic mirror of the second resonator. The cavity is formed based on the support of the bottom electrode of the second resonator in the thickness direction. At least a portion of the cavity is located in the thickness direction between the effective regions of the first resonator and the effective regions of the second resonator.

19. The component according to claim 1 or 18, wherein: The at least two resonators include a first resonator, a second resonator, and a third resonator stacked in the thickness direction; An acoustic decoupling layer is provided between the top electrode of the first resonator and the bottom electrode of the second resonator. The acoustic decoupling layer is a first acoustic decoupling layer. A cavity-shaped second acoustic decoupling layer is provided between the top electrode of the second resonator and the bottom electrode of the third resonator. The second acoustic decoupling layer constitutes the acoustic mirror of the third resonator.

20. The component of claim 19, wherein: The boundary of the second acoustic decoupling layer is located outside the boundary of the first acoustic decoupling layer in the horizontal direction.

21. A method for manufacturing a bulk acoustic resonator assembly, comprising: Step 1: Form a first structure for a first bulk acoustic resonator on the surface of a substrate, the first bulk acoustic resonator including a first acoustic mirror, a first bottom electrode, a first piezoelectric layer, and a first top electrode; Step 2: Apply a patterned sacrificial material layer to the first structure formed in Step 1; Step 3: Form a second structure for a second bulk acoustic resonator on the structure of step 2. The second bulk acoustic resonator includes a second acoustic mirror, a second bottom electrode, a second piezoelectric layer, and a second top electrode. The sacrificial material layer is located between the first top electrode and the second bottom electrode in the thickness direction of the substrate. Step 4: Release the sacrificial material layer to form a cavity, which constitutes the second acoustic mirror of the second bulk acoustic resonator; The cavity is formed based on the support of the second bottom electrode in the thickness direction; At least a portion of the cavity is located in the thickness direction between the effective region of the first bulk acoustic resonator and the effective region of the second bulk acoustic resonator.

22. The method according to claim 21, wherein: Step 2 also includes providing supports in the sacrificial material layer.

23. A filter comprising a bulk acoustic resonator assembly according to any one of claims 1-20.

24. An electronic device comprising the filter of claim 23 or the bulk acoustic resonator assembly of any one of claims 1-20.

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