Bulk acoustic resonators, filters, and electronic devices with closely spaced electrode leads.

Abstract

This invention relates to a bulk acoustic wave resonator. The resonator includes: a substrate; an acoustic mirror; a bottom electrode; a top electrode; and a piezoelectric layer, wherein: the resonator further includes a first electrode lead-out terminal, the first electrode lead-out terminal passing through the piezoelectric layer and electrically connected to an electrode connection terminal of the bottom electrode, and the inner side of the connection surface between the first electrode lead-out terminal and the bottom electrode is horizontally located inside the boundary of the acoustic mirror; and / or the resonator further includes a second electrode lead-out terminal, the electrode connection terminal of the top electrode is provided with a bridge portion, the second electrode lead-out terminal includes a second covering portion at least partially covering the outer slope of the bridge portion, the inner end of the second covering portion being horizontally spaced from the inner edge of the bridge portion. This invention also relates to 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, a filter having the resonator, and an electronic device. Background Technology

[0002] Electronic components, as the basic elements of electronic devices, are widely used in all aspects of our lives. Not only are our current mobile phones, cars, and home appliances full of various electronic components, but the technologies that will change the world in the future, such as artificial intelligence, the Internet of Things, and 5G communication, will still rely on electronic components as their foundation.

[0003] Electronic devices can exhibit different characteristics and advantages depending on their working principles. Among all electronic devices, those that operate using the piezoelectric effect (or inverse piezoelectric effect) are a very important category. Thin-film bulk acoustic resonators (FBARs) possess excellent characteristics such as small size (μm level), high resonant frequency (GHz), high quality factor (1000), large power capacity, and good roll-off effect. Their filters are gradually replacing traditional surface acoustic wave (SAW) filters and ceramic filters, playing a significant role in the field of wireless communication radio frequency. Their high sensitivity advantage can also be applied to sensing fields such as biology, physics, and medicine.

[0004] FBARs primarily utilize the piezoelectric and inverse piezoelectric effects of piezoelectric materials to generate bulk acoustic waves, thereby creating resonance within the device. Because FBARs possess a series of inherent advantages such as high quality factor, large power capacity, high frequency (up to 2-10 GHz or even higher), and good compatibility with standard integrated circuits (ICs), they can be widely used in high-frequency radio frequency application systems.

[0005] As wireless communication speeds continue to increase, the operating frequencies of radio frequency devices are required to increase accordingly. To manufacture higher-frequency FBAR filters, the resonant frequency of the FBAR resonator must also be increased. In existing FBAR structures, the electrodes are thinner at higher resonant frequencies, resulting in poorer electrode conductivity. This affects the impedance value of the resonator at the series resonant point, ultimately leading to a deterioration of the Q value at and near the series resonant point Qs. Summary of the Invention

[0006] The present invention is proposed to alleviate or solve at least one of the above-mentioned problems in the prior art.

[0007] According to one aspect of an embodiment of the present invention, a bulk acoustic resonator is provided, comprising:

[0008] Base;

[0009] Acoustic mirror;

[0010] Bottom electrode;

[0011] Top electrode; and

[0012] piezoelectric layer

[0013] in:

[0014] The resonator further includes a first electrode lead-out, which passes through the piezoelectric layer and is electrically connected to the electrode connection end of the bottom electrode. The inner side of the connection surface between the first electrode lead-out and the bottom electrode is located inside the boundary of the acoustic mirror in the horizontal direction; and / or

[0015] The resonator further includes a second electrode lead-out end, and the electrode connection end of the top electrode is provided with a bridge portion. The second electrode lead-out end includes a second covering portion that at least partially covers the outer slope of the bridge portion, and the inner end of the second covering portion is horizontally spaced from the inner edge of the bridge portion.

[0016] Embodiments of the present invention also relate to a bulk acoustic resonator, comprising:

[0017] Base;

[0018] Acoustic mirror;

[0019] Bottom electrode;

[0020] Top electrode; and

[0021] piezoelectric layer

[0022] in:

[0023] The resonant frequency of the resonator is not less than 2 GHz, the electrode thickness of the bottom electrode within the effective region of the resonator is less than 0.5 μm, and the resonator further includes a first electrode lead-out terminal, which passes through the piezoelectric layer and is electrically connected to the electrode connection terminal of the bottom electrode. The distance between the inner end of the contact portion of the first electrode lead-out terminal and the piezoelectric layer and the non-electrode connection terminal of the top electrode in the horizontal direction is not less than half of the wavelength of the sound wave corresponding to the resonant frequency of the resonator, and not greater than 10 μm; and / or

[0024] The resonant frequency of the resonator is not less than 2 GHz, the electrode thickness of the top electrode in the effective area of ​​the resonator is less than 0.5 μm, and the resonator also includes a second electrode lead-out end. The electrode connection end of the top electrode is provided with a bridge portion. The second electrode lead-out end includes a second covering portion that at least partially covers the outer slope of the bridge portion. The inner end of the second covering portion is spaced apart from the inner edge of the bridge portion in the horizontal direction.

[0025] Embodiments of the present invention also relate to a filter, including the aforementioned bulk acoustic resonator.

[0026] Embodiments of the present invention also relate to an electronic device, including the filter or the resonator described above. Attached Figure Description

[0027] 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:

[0028] Figure 1 A cross-sectional schematic diagram showing the positions of the electrode leads of the top electrode and the electrode leads of the bottom electrode in a bulk acoustic resonator in the prior art.

[0029] Figure 2-7 This is a cross-sectional schematic diagram of a bulk acoustic resonator according to different exemplary embodiments of the present invention. Detailed Implementation

[0030] 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.

[0031] Figure 1 This is a cross-sectional schematic diagram showing the positions of the electrode leads of the top electrode and the bottom electrode of a bulk acoustic resonator in the prior art. Figure 1 As can be seen, the electrode lead-out end 113a of the bottom electrode is located outside the boundary of the acoustic mirror 103, and the electrode lead-out end 113b of the top electrode is located outside the gap 111a defined by the bridge portion 111. For Figure 1 In the structure of the resonator, the higher the resonant frequency, the thinner the electrode, which leads to an increase in the electrical loss of the electrical connection channel between the electrode leads and the electrode, and a deterioration in the Q value of the resonator.

[0032] Figure 2-7 This is a schematic cross-sectional view of a bulk acoustic resonator according to different exemplary embodiments of the present invention. In the present invention, by redefining the structural and positional relationships between the electrode leads, the electrodes, and the piezoelectric layer, the Q-value degradation of the resonator caused by electrode thinning can be compensated, thereby improving the Qs of the resonator and the Q-value in its vicinity.

[0033] The reference numerals in the drawings of this invention are explained as follows:

[0034] 101: Substrate, with optional materials including single-crystal silicon, gallium nitride, gallium arsenide, sapphire, quartz, silicon carbide, diamond, etc.

[0035] 103: Acoustic mirror, which can be a cavity, or it can be a Bragg reflector layer or other equivalent forms. The embodiment shown in this invention uses a cavity.

[0036] 105: Bottom electrode, materials can be selected from molybdenum, ruthenium, gold, aluminum, magnesium, tungsten, copper, titanium, iridium, osmium, chromium or composites of the above metals or their alloys, etc.

[0037] 107: The piezoelectric layer 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 doped with a certain atomic ratio of the above materials. Mixed materials, such as doped aluminum nitride, contain 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.

[0038] 109: Top electrode, whose material can be the same as the bottom electrode. Materials can be 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.

[0039] 111: Bridge section, located at the electrode connection end of the top electrode.

[0040] 111a: A gap, defined by the bridge portion, is located between the bridge portion 111 and the upper surface of the piezoelectric layer 107. It can be an air gap or a dielectric layer, both of which are within the protection scope of this invention.

[0041] 113: The electrode connection end of the bottom electrode, which can be made simultaneously with the top electrode. The material can be molybdenum, ruthenium, gold, aluminum, magnesium, tungsten, copper, titanium, iridium, osmium, chromium or a composite or alloy of the above metals.

[0042] 113a: The electrode lead-out terminal of the bottom electrode, which is generally made of a high-conductivity metal, such as molybdenum, ruthenium, gold, aluminum, magnesium, tungsten, copper, titanium, iridium, osmium, chromium or a composite or alloy of the above metals.

[0043] 113b: The electrode lead-out terminal of the top electrode, which is generally made of a high-conductivity metal, such as molybdenum, ruthenium, gold, aluminum, magnesium, tungsten, copper, titanium, iridium, osmium, chromium or a composite or alloy of the above metals.

[0044] 115: Passivation layer or process layer, set on the top electrode of the resonator. The function of the process layer can be a mass conditioning load or a passivation layer. Its material can be a dielectric material, such as silicon dioxide, aluminum nitride, silicon nitride, etc.

[0045] 117: Additional metal layer, the material is generally a high conductivity metal, such as molybdenum, ruthenium, gold, aluminum, magnesium, tungsten, copper, titanium, iridium, osmium, chromium or a composite or alloy of the above metals, or the same material as the bottom electrode.

[0046] 119: A cantilever, located at the non-electrode connection end of the top electrode, with a gap 119a below it.

[0047] 119a: A gap defined by the cantilever 119, located between the cantilever 119 and the upper surface of the piezoelectric layer 107. It can be an air gap or a dielectric layer, both of which are within the protection scope of this invention.

[0048] like Figure 2 As shown, the electrode lead-out end 113a passes through the piezoelectric layer 107 and is electrically connected to the electrode connection end 113 of the bottom electrode 105, and the electrode lead-out end 113a extends inward to the inner side of the boundary of the acoustic mirror 103. In other words, in Figure 2 In the middle, the portion where the electrode lead-out end 113a connects to the electrode connection end 113 spans the boundary of the acoustic mirror 103. The electrode lead-out end 113a covers the surface of the electrode connection end 113 of the bottom electrode 105 and the sidewall of the conductive via in the piezoelectric layer 107.

[0049] like Figure 2 As shown, in an optional embodiment, the electrode lead-out terminal 113a further includes a covering portion M covering the upper surface of the piezoelectric layer 107. The covering portion M can ensure that 113a completely covers the boundary of 105.

[0050] To ensure that the cover M does not affect the effective region of the resonator, a distance L1 can be defined to ensure sufficient acoustic decoupling isolation between the cover M and the edge of the non-electrode connection end of the top electrode. L1 is defined as: the inner end of the electrode lead 113a that contacts the piezoelectric layer (in... Figure 2 The middle (right end) and the non-electrode connection end of the top electrode 109 (in Figure 2 The distance in the horizontal direction (where the left end is in the middle) is the distance from the middle end. In one embodiment of the present invention, optionally, L1 ≥ λ / 2, where λ is the wavelength of the sound wave corresponding to the resonant frequency of the resonator.

[0051] See Figure 2The top electrode 109 has a bridge portion 111 at its electrode connection end, and a gap 111a is defined below the bridge portion. Figure 2 In the middle, the bridge section 111 has a horizontal section, such as... Figure 2 In the embodiment shown, the electrode lead-out end 113b of the top electrode covers the right slope (i.e. the outer slope) of the bridge portion and a portion of the horizontal portion.

[0052] It should be noted that, in this invention, the outer slope of the bridge section includes a single slope, a stepped surface, multiple slopes, etc., between the top (highest) and the outermost (lowest) portion of the bridge section, all of which are within the scope of protection of this invention. In this invention, the horizontal portion of the bridge section corresponds to the portion forming the highest or top of the bridge section.

[0053] like Figure 2 As shown, the inner end of electrode lead 113b ( Figure 2 The left end of the bridge 111 is at a distance L2 from the inner edge of the gap 111a of the bridge 111 in the horizontal direction.

[0054] In one embodiment of the invention, L2 is defined to ensure the effective region of the corresponding electrode lead 113b and the resonator (the effective region is the overlapping area of ​​the top electrode 109, piezoelectric layer 107, and bottom electrode 105 in the thickness direction of the resonator, such as...). Figure 2 As shown in A1, sufficient acoustic decoupling and isolation are achieved. Figure 2 In this context, L2 is also the distance between the inner end of electrode lead 113b and the edge of top electrode 109 in the effective region. In an optional embodiment, L2 ≥ λ / 2, where λ is the acoustic wavelength corresponding to the resonant frequency of the resonator.

[0055] use Figure 2 In the technical solution of the embodiment shown, since the part of the electrode lead-out end 113a connected to the bottom electrode 105 spans the boundary of the acoustic mirror 103, and the inner end of the electrode lead-out end 113b covers a part of the horizontal part of the bridge portion 111, the electrode lead-out end is closer to the effective region of the resonator. This reduces the resistance of the electrode portion outside the effective region and between the electrode lead-out end, thus improving the Qs value at the series resonant frequency of the resonator and the Q value in the vicinity.

[0056] It should be pointed out that, in Figure 2 In the illustrated embodiment, only electrode lead-out terminal 113a may be provided, without electrode lead-out terminal 113b, or only electrode lead-out terminal 113b may be provided without electrode lead-out terminal 113a. In the case where electrode lead-out terminal 113a is provided, the electrode connection terminal of the top electrode may not have a bridge portion 111. Furthermore, although in Figure 2In the illustrated embodiment, the non-electrode connection end of the top electrode is provided with a cantilever 119, but the non-electrode connection end of the top electrode may also be without a cantilever. Furthermore, in Figure 2 In the illustrated embodiment, the portion where the electrode lead-out end 113a connects to the electrode connection end 113 horizontally spans the boundary of the acoustic mirror 103. However, the outer end of the portion where the electrode lead-out end 113a connects to the electrode connection end 113 may also be located inside the boundary of the acoustic mirror 103. All of the above are within the scope of protection of this invention and are equally applicable. Figure 3-7 The example shown.

[0057] Figure 3 The structure shown is similar to Figure 2 The difference in the structure shown is that, Figure 3 In the middle, the electrode lead-out end 113b only covers a part of the outer slope of the bridge portion 111, and does not cover the horizontal portion of the bridge portion 111.

[0058] like Figure 2 As shown, when the electrode lead-out 113b is positioned on the horizontal portion of the bridge portion 111, although the Qs value of the resonator at the series resonant frequency can be increased, it will affect other performance characteristics of the resonator to some extent, such as increasing acoustic loss. To maximize the coverage of the bridge portion 111 by the electrode lead-out 113b while minimizing the impact of this coverage on the resonator's performance, as... Figure 3 As shown, the electrode lead-out end 113b can be extended only to the outer slope of the bridge portion. For example... Figure 3 As shown, the electrode lead-out end 113b covers a portion of the outer slope of the bridge portion 111, and there is a horizontal distance L3 between the inner end of the electrode lead-out end 113b and the outer edge of the horizontal portion of the bridge portion 111. In an optional embodiment, L3 is not greater than 2μm, for example, 1μm or 0μm.

[0059] In an optional embodiment, the side surface of the piezoelectric layer 107 can be etched into a bevel to improve the coverage of the electrode lead-out terminal 113a.

[0060] Figure 4 This is a cross-sectional schematic diagram of a bulk acoustic resonator according to another exemplary embodiment of the present invention. Figure 4 and Figure 3 The difference in the structure shown is that, Figure 4 In this case, the inner end of the electrode lead-out 113a does not cover the upper surface of the piezoelectric layer 107 as in case 3, but instead forms a cantilever. Specifically, as shown... Figure 4 As shown, an outlet wing is provided on the inner side or inner end of the electrode lead-out terminal 113a. A gap is formed between the outlet wing and the upper surface of the piezoelectric layer 107, and the outer edge of the outlet wing and the non-electrode connection end of the top electrode 109 are separated by a distance L4 in the horizontal direction. Figure 4 In this configuration, the presence of the lead-out fins facilitates sufficient acoustic decoupling and isolation between the electrode lead-out 113a and the effective region. L4 is defined as the horizontal distance between the outer edge of the lead-out fin of electrode lead-out 113a and the fin of the top electrode 109. In an optional embodiment, L4 ≥ λ / 2, where λ is the acoustic wavelength corresponding to the resonant frequency of the resonator.

[0061] exist Figure 4 In the middle, because the lead-out end fins and the piezoelectric layer do not contact each other, it is possible to... Figure 2 Replace the distance L1 with L4; if the distances L1 and L4 are equal, such as both being half a wavelength, Figure 4 The piezoelectric layer etching end face is more than Figure 2 Being closer to the effective region allows for further reduction of resistive losses and improvement of the Q value. In other words, Figure 4 and Figure 2 The piezoelectric layer etching end face is a distance of M.

[0062] Compared to, for example Figure 3 The embodiment shown, Figure 4 The implementation shown allows the inner end of the electrode lead 113a of the electrode connection terminal of the contact bottom electrode to be closer to the effective region, thereby further improving the Qs value of the resonator at the series resonant frequency and the Q value in the vicinity.

[0063] Figure 5 A schematic cross-sectional view of a bulk acoustic resonator according to another exemplary embodiment of the present invention. It is related to... Figure 2 The difference in the structure shown is that, Figure 5 In this process, an additional metal layer 117 is provided between the electrode lead-out end 113a and the bottom electrode 105; in addition, a passivation layer 115 is provided on the top electrode 109, the passivation layer 115 covers a part of the horizontal portion of the bridge portion 111, and the inner end of the electrode lead-out end 113b is covered by a portion of the passivation layer 115 on the horizontal portion of the bridge portion 111.

[0064] When a passivation layer 115 is provided on the top electrode 109, the inner end of the electrode lead-out portion 113b can further extend to the outer end of the passivation layer 115. In other words, as Figure 5 As shown, the inner end of the electrode lead-out portion 113b is covered by the passivation layer 115 above the bridge portion 111, and the inner end of the electrode lead-out portion 113b is horizontally spaced from the inner edge of the bridge portion 111.

[0065] Furthermore, before growing the electrode lead-out portion 113a, the piezoelectric layer 107 needs to be etched to expose the bottom electrode 105. Etching the piezoelectric layer 107 may damage the bottom electrode 105, and there is even a risk of etching through it. Therefore, in the region corresponding to the electrode lead-out portion 113a, such as... Figure 5 As shown, an additional metal layer 117 is added above the electrode connection portion 113 of the bottom electrode 105 to prevent damage to the bottom electrode 105 during the etching of the piezoelectric layer 107, thereby improving structural reliability. On the other hand, the material of the additional metal layer 117 can be a metal, which can further improve the electrode conductivity.

[0066] like Figure 5 As shown, the additional metal layer 117 spans the boundary of the acoustic mirror 103 in the horizontal direction and is separated from the non-electrode connection end of the top electrode 109 by a distance L5 in the horizontal direction. In an optional embodiment, L5 ≥ λ / 2, where λ is the acoustic wavelength corresponding to the resonant frequency of the resonator.

[0067] In an optional embodiment, the inner end of the additional metal layer 117 is closer to the non-electrode connection end of the top electrode 109 than the inner end of the electrode lead-out end 113a.

[0068] like Figure 6 As shown, the additional metal layer 117 can also be disposed between the bottom electrode 105 and the substrate 101.

[0069] like Figure 7 As shown, the additional metal layer 117 can be formed directly by thickening the electrode connection end of the bottom electrode. Alternatively, when the additional metal layer 117 and the bottom electrode 105 are made of the same metal, the shape of the bottom electrode 105 can be changed to achieve the effect of the additional metal layer.

[0070] In this invention, for example, a bulk acoustic resonator with a resonant frequency of not less than 2 GHz, where the electrode thickness in the effective region is less than 0.5 μm, by changing the lateral position of the electrode leads 113a or 113b as described above, the length of the electrode portion between the effective region and the electrode leads can be reduced, thereby lowering the resistance of that electrode portion. Correspondingly, by ensuring that the distance in the horizontal direction between the inner end of the contact portion between the electrode lead 113a and the piezoelectric layer 107 and the non-electrode connection end of the top electrode 109 is not less than half the wavelength of the acoustic wave corresponding to the resonant frequency of the resonator, and not greater than 10 μm, a structure can be achieved where the resonant frequency of the resonator is not less than 2 GHz, and the electrode thickness of the bottom electrode in the effective region of the resonator is less than 0.5 μm. Correspondingly, when a bridge portion 111 is provided at the electrode connection end of the top electrode 109, the electrode lead-out end 113b includes a covering portion that at least partially covers the outer slope of the bridge portion 111 (the inner end of the covering portion is horizontally spaced from the inner edge of the bridge portion 111), which can achieve a structure in which the resonant frequency of the resonator is not less than 2 GHz and the electrode thickness of the top electrode in the effective region of the resonator is less than 0.5 μm.

[0071] 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.

[0072] 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.

[0073] In this invention, "inner" and "outer" are relative to the center (i.e., the center of the effective region) of the resonator (the overlapping area of ​​the piezoelectric layer, top electrode, bottom electrode, and acoustic mirror in the thickness direction of the resonator constitutes the effective region) in the lateral or radial direction. A component's side or end 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.

[0074] 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.

[0075] Based on the above, the present invention proposes the following technical solution:

[0076] 1. A bulk acoustic resonator, comprising:

[0077] Base;

[0078] Acoustic mirror;

[0079] Bottom electrode;

[0080] Top electrode; and

[0081] piezoelectric layer

[0082] in:

[0083] The resonator further includes a first electrode lead-out, which passes through the piezoelectric layer and is electrically connected to the electrode connection end of the bottom electrode. The inner side of the connection surface between the first electrode lead-out and the bottom electrode is located inside the boundary of the acoustic mirror in the horizontal direction; and / or

[0084] The resonator further includes a second electrode lead-out end, and the electrode connection end of the top electrode is provided with a bridge portion. The second electrode lead-out end includes a second covering portion that at least partially covers the outer slope of the bridge portion, and the inner end of the second covering portion is horizontally spaced from the inner edge of the bridge portion.

[0085] 2. The resonator according to 1, wherein:

[0086] The inner portion of the first electrode lead-out end includes a first covering portion that covers the upper surface of the piezoelectric layer.

[0087] 3. The resonator according to 2, wherein:

[0088] The first covering portion and the non-electrode connection end of the top electrode are separated by a first distance (L1) in the horizontal direction.

[0089] 4. The resonator according to 3, wherein:

[0090] The first distance is not less than half the wavelength of the sound wave corresponding to the resonant frequency of the resonator.

[0091] 5. The resonator according to claim 1, wherein:

[0092] The inner portion of the first electrode lead-out end includes a lead-out end flap, and a gap is formed between the lead-out end flap and the upper surface of the piezoelectric layer. The outer edge of the lead-out end flap and the non-electrode connection end of the top electrode have a fourth distance (L4) in the horizontal direction.

[0093] 6. The resonator according to 5, wherein:

[0094] The fourth distance is not less than half the wavelength of the sound wave corresponding to the resonant frequency of the resonator.

[0095] 7. The resonator according to claim 1, wherein:

[0096] The resonator further includes an additional metal layer disposed between the first electrode lead-out end and the electrode connection end of the bottom electrode;

[0097] The inner end of the metal supplementary layer is located inside the boundary of the acoustic mirror in the horizontal direction, and there is a fifth distance (L5) between it and the non-electrode connection end of the top electrode in the horizontal direction.

[0098] 8. The resonator according to claim 1, wherein:

[0099] The resonator also includes an additional metal layer disposed between the electrode connection end of the bottom electrode and the substrate;

[0100] The inner end of the metal supplementary layer is located inside the boundary of the acoustic mirror in the horizontal direction, and there is a fifth distance (L5) between it and the non-electrode connection end of the top electrode in the horizontal direction.

[0101] 9. The resonator according to claim 1, wherein:

[0102] The upper surface of the electrode connection end of the bottom electrode includes an electrode thickening layer;

[0103] The inner end of the electrode thickening layer is located inside the boundary of the acoustic mirror in the horizontal direction, and there is a fifth distance (L5) between it and the non-electrode connection end of the top electrode in the horizontal direction.

[0104] 10. The resonator according to any one of 7-9, wherein:

[0105] The fifth distance is not less than half the wavelength of the sound wave corresponding to the resonant frequency of the resonator.

[0106] 11. The resonator according to any one of 1-9, wherein:

[0107] The bridge section has a horizontal section;

[0108] The second covering portion covers the outer slope and a portion of the horizontal portion, and the inner end of the second covering portion and the inner edge of the bridge portion are at a second distance (L2) in the horizontal direction.

[0109] 11. The resonator according to 10, wherein:

[0110] The second distance is not less than half the wavelength of the sound wave corresponding to the resonant frequency of the resonator.

[0111] 12. The resonator according to any one of 1-9, wherein:

[0112] The bridge section has a horizontal section;

[0113] The second covering portion covers a part of the outer slope, and the inner end of the second covering portion and the outer edge of the horizontal portion are at a third distance (L3) in the horizontal direction.

[0114] 13. The resonator according to 12, wherein:

[0115] The third distance is no greater than 2μm.

[0116] 14. The resonator according to any one of 1-9, wherein:

[0117] A passivation layer is provided on the upper surface of the top electrode, and the passivation layer also covers at least a portion of the bridge portion;

[0118] The second cover portion covers the passivation layer above the bridge portion, and the inner end of the second cover portion is horizontally spaced from the inner edge of the bridge portion.

[0119] 15. A bulk acoustic resonator, comprising:

[0120] Base;

[0121] Acoustic mirror;

[0122] Bottom electrode;

[0123] Top electrode; and

[0124] piezoelectric layer

[0125] in:

[0126] The resonant frequency of the resonator is not less than 2 GHz, the electrode thickness of the bottom electrode within the effective region of the resonator is less than 0.5 μm, and the resonator further includes a first electrode lead-out terminal, which passes through the piezoelectric layer and is electrically connected to the electrode connection terminal of the bottom electrode. The distance between the inner end of the contact portion of the first electrode lead-out terminal and the piezoelectric layer and the non-electrode connection terminal of the top electrode in the horizontal direction is not less than half of the wavelength of the sound wave corresponding to the resonant frequency of the resonator, and not greater than 10 μm; and / or

[0127] The resonant frequency of the resonator is not less than 2 GHz, the electrode thickness of the top electrode in the effective area of ​​the resonator is less than 0.5 μm, and the resonator also includes a second electrode lead-out end. The electrode connection end of the top electrode is provided with a bridge portion. The second electrode lead-out end includes a second covering portion that at least partially covers the outer slope of the bridge portion. The inner end of the second covering portion is spaced apart from the inner edge of the bridge portion in the horizontal direction.

[0128] 16. The resonator according to 1 or 15, wherein:

[0129] The non-electrode connection end of the top electrode is provided with a top electrode wing.

[0130] 17. The resonator according to 1 or 15, wherein:

[0131] The connection surface between the first electrode lead-out end and the bottom electrode spans the boundary of the acoustic mirror in the horizontal direction.

[0132] 18. A filter comprising a bulk acoustic resonator according to any one of 1-17.

[0133] 19. An electronic device comprising the filter according to claim 18, or the bulk acoustic resonator according to any one of claims 1-17.

[0134] 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, comprising: Base; Acoustic mirror; Bottom electrode; Top electrode; and piezoelectric layer in: The resonator further includes a first electrode lead-out end, which passes through the piezoelectric layer and is electrically connected to the electrode connection end of the bottom electrode, and the inner side of the connection surface between the first electrode lead-out end and the bottom electrode is located inside the boundary of the acoustic mirror in the horizontal direction. The connection surface between the first electrode lead-out end and the bottom electrode spans the boundary of the acoustic mirror in the horizontal direction.

2. The resonator according to claim 1, wherein: The resonator further includes a second electrode lead-out end, and the electrode connection end of the top electrode is provided with a bridge portion. The second electrode lead-out end includes a second covering portion that at least partially covers the outer slope of the bridge portion, and the inner end of the second covering portion is horizontally spaced from the inner edge of the bridge portion.

3. The resonator according to claim 1, wherein: The inner portion of the first electrode lead-out end includes a first covering portion that covers the upper surface of the piezoelectric layer.

4. The resonator according to claim 3, wherein: The first covering portion and the non-electrode connection end of the top electrode are separated by a first distance (L1) in the horizontal direction.

5. The resonator according to claim 4, wherein: The first distance is not less than half the wavelength of the sound wave corresponding to the resonant frequency of the resonator.

6. The resonator according to claim 1, wherein: The inner portion of the first electrode lead-out end includes a lead-out end flap, and a gap is formed between the lead-out end flap and the upper surface of the piezoelectric layer. The outer edge of the lead-out end flap and the non-electrode connection end of the top electrode have a fourth distance (L4) in the horizontal direction.

7. The resonator according to claim 6, wherein: The fourth distance is not less than half the wavelength of the sound wave corresponding to the resonant frequency of the resonator.

8. The resonator according to claim 1, wherein: The resonator further includes an additional metal layer disposed between the first electrode lead-out end and the electrode connection end of the bottom electrode; The inner end of the metal supplementary layer is located inside the boundary of the acoustic mirror in the horizontal direction, and there is a fifth distance (L5) between it and the non-electrode connection end of the top electrode in the horizontal direction.

9. The resonator according to claim 1, wherein: The resonator also includes an additional metal layer disposed between the electrode connection end of the bottom electrode and the substrate; The inner end of the metal supplementary layer is located inside the boundary of the acoustic mirror in the horizontal direction, and there is a fifth distance (L5) between it and the non-electrode connection end of the top electrode in the horizontal direction.

10. The resonator according to claim 1, wherein: The upper surface of the electrode connection end of the bottom electrode includes an electrode thickening layer; The inner end of the electrode thickening layer is located inside the boundary of the acoustic mirror in the horizontal direction, and there is a fifth distance (L5) between it and the non-electrode connection end of the top electrode in the horizontal direction.

11. The resonator according to any one of claims 8-10, wherein: The fifth distance is not less than half the wavelength of the sound wave corresponding to the resonant frequency of the resonator.

12. The resonator according to claim 2, wherein: The bridge section has a horizontal section; The second covering portion covers the outer slope and a portion of the horizontal portion, and the inner end of the second covering portion and the inner edge of the bridge portion are at a second distance (L2) in the horizontal direction.

13. The resonator according to claim 12, wherein: The second distance is not less than half the wavelength of the sound wave corresponding to the resonant frequency of the resonator.

14. The resonator according to claim 2, wherein: The bridge section has a horizontal section; The second covering portion covers a part of the outer slope, and the inner end of the second covering portion and the outer edge of the horizontal portion are at a third distance (L3) in the horizontal direction.

15. The resonator according to claim 14, wherein: The third distance is no greater than 2μm.

16. The resonator according to claim 2, wherein: A passivation layer is provided on the upper surface of the top electrode, and the passivation layer also covers at least a portion of the bridge portion; The second cover portion covers the passivation layer above the bridge portion, and the inner end of the second cover portion is horizontally spaced from the inner edge of the bridge portion.

17. A bulk acoustic resonator, comprising: Base; Acoustic mirror; Bottom electrode; Top electrode; and piezoelectric layer in: The resonant frequency of the resonator is not less than 2 GHz, the electrode thickness of the bottom electrode in the effective area of ​​the resonator is less than 0.5 μm, and the resonator also includes a first electrode lead-out end, which passes through the piezoelectric layer and is electrically connected to the electrode connection end of the bottom electrode. The distance between the inner end of the contact portion of the first electrode lead-out end and the non-electrode connection end of the top electrode in the horizontal direction is not less than half of the wavelength of the sound wave corresponding to the resonant frequency of the resonator, and not greater than 10 μm. The connection surface between the first electrode lead-out end and the bottom electrode spans the boundary of the acoustic mirror in the horizontal direction.

18. The resonator according to claim 17, wherein: The resonant frequency of the resonator is not less than 2 GHz, the electrode thickness of the top electrode in the effective area of ​​the resonator is less than 0.5 μm, and the resonator also includes a second electrode lead-out end. The electrode connection end of the top electrode is provided with a bridge portion. The second electrode lead-out end includes a second covering portion that at least partially covers the outer slope of the bridge portion. The inner end of the second covering portion is spaced apart from the inner edge of the bridge portion in the horizontal direction.

19. The resonator according to claim 1 or 17, wherein: The non-electrode connection end of the top electrode is provided with a top electrode wing.

20. A filter comprising a bulk acoustic resonator according to any one of claims 1-19.

21. An electronic device comprising the filter of claim 20, or the bulk acoustic resonator of any one of claims 1-19.

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