WO2022161142A1 - Résonateur acoustique en volume, filtre et dispositif électronique - Google Patents

Résonateur acoustique en volume, filtre et dispositif électronique Download PDF

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WO2022161142A1
WO2022161142A1 PCT/CN2022/070884 CN2022070884W WO2022161142A1 WO 2022161142 A1 WO2022161142 A1 WO 2022161142A1 CN 2022070884 W CN2022070884 W CN 2022070884W WO 2022161142 A1 WO2022161142 A1 WO 2022161142A1
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bottom electrode
piezoelectric layer
electrically connected
electrical connection
layer
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PCT/CN2022/070884
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English (en)
Chinese (zh)
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张孟伦
庞慰
杨清瑞
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诺思(天津)微系统有限责任公司
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Publication of WO2022161142A1 publication Critical patent/WO2022161142A1/fr

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    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
    • H03H3/00—Apparatus or processes specially adapted for the manufacture of impedance networks, resonating circuits, resonators
    • H03H3/007—Apparatus or processes specially adapted for the manufacture of impedance networks, resonating circuits, resonators for the manufacture of electromechanical resonators or networks
    • H03H3/02—Apparatus or processes specially adapted for the manufacture of impedance networks, resonating circuits, resonators for the manufacture of electromechanical resonators or networks for the manufacture of piezoelectric or electrostrictive resonators or networks
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
    • H03H9/00—Networks comprising electromechanical or electro-acoustic devices; Electromechanical resonators
    • H03H9/02—Details
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
    • H03H9/00—Networks comprising electromechanical or electro-acoustic devices; Electromechanical resonators
    • H03H9/15—Constructional features of resonators consisting of piezoelectric or electrostrictive material
    • H03H9/17—Constructional features of resonators consisting of piezoelectric or electrostrictive material having a single resonator

Definitions

  • Embodiments of the present invention relate to the field of semiconductors, and in particular, to a bulk acoustic wave resonator, a filter, and an electronic device.
  • thin film bulk acoustic resonator As a kind of MEMS device, thin film bulk acoustic resonator (FBAR) has the advantages of small size, light weight, low insertion loss, high frequency bandwidth and high quality factor.
  • the structural main body of the thin film bulk acoustic wave resonator is a "sandwich" structure composed of an electrode-piezoelectric film-electrode, that is, a piezoelectric material is sandwiched between two metal electrode layers.
  • the FBAR uses the inverse piezoelectric effect to convert the input electrical signal into mechanical resonance, and then uses the piezoelectric effect to convert the mechanical resonance into an electrical signal output.
  • FIG. 1A The schematic cross-sectional structure of the existing thin film bulk acoustic wave resonator is shown in FIG. 1A , which shows a part of the “sandwich” structure formed by the piezoelectric layer 202 , the top electrode 201 and the bottom electrode 203 arranged on the substrate 204 .
  • the area shown by A1 is the effective area of the resonator. Outside the effective area, when the resonator vibrates, the acoustic wave energy will extend the piezoelectric layer 202 and transmit to the outside of the effective area, resulting in energy leakage, as shown by Q1 in the figure, This reduces the Q of the resonator.
  • the resonator requires a support structure for mechanical fixation and a substrate for carrying; in general, the acoustic energy loss of the resonator mainly comes from leakage from the effective area through the support structure to the support base; in the traditional structure, the support structure is the extension of the piezoelectric layer 202 and The combination of the extension of the bottom electric layer (piezoelectric layer 202 + top electrode 201 or piezoelectric layer 202 + bottom electrode 203), as shown in FIG. 1A, this structure causes the leakage of acoustic wave energy, and then the Q value (especially the parallel resonance point and its nearby Q value) is lower.
  • part of the piezoelectric layer can be etched away in the conventional known improved structure.
  • the transverse Lamb wave transmitted in the piezoelectric layer 202 will be reflected back. (See Q2) in the active area A1, but the transverse Lamb wave transmitted in the bottom electrode B1 area will bring serious parasitic modes in the process of being reflected back to the active area A1 (refer to Q3), affecting the performance of the device, which is urgently needed. improve.
  • the present invention is proposed to alleviate or solve at least one aspect of the above-mentioned problems in the prior art.
  • a bulk acoustic wave resonator including a substrate, a top electrode, a piezoelectric layer, a bottom electrode, and an acoustic mirror.
  • a support layer is arranged between the substrate and the resonant structure, and the piezoelectric layer is a single crystal piezoelectric layer arranged substantially parallel to the substrate.
  • a part of the outer end of the non-electrically connected end of the bottom electrode is covered by the support layer, and at the bottom electrode At least a portion of the piezoelectric layer of the non-electrical connection end is removed, and at least a portion of the upper surface of the non-electrical connection end of the bottom electrode is flush with the upper surface of the support layer.
  • a filter including the aforementioned bulk acoustic wave resonator.
  • an electronic device including the aforementioned bulk acoustic wave resonator or the aforementioned filter.
  • FIGS. 1A and 1B are partial cross-sectional views of a conventional bulk acoustic wave resonator
  • FIG. 2 is a schematic top view of a bulk acoustic wave resonator
  • FIG. 3 is a schematic cross-sectional view of a bulk acoustic wave resonator along line OC' in FIG. 2 according to an exemplary embodiment of the present invention
  • 4A-4K exemplarily show the process of manufacturing the bulk acoustic wave resonator shown in FIG. 3;
  • FIG. 5-19 are schematic cross-sectional views along line OC' in FIG. 2 of a bulk acoustic wave resonator according to various exemplary embodiments of the present invention.
  • 20-22 are schematic cross-sectional views along line OB of FIG. 2 of a bulk acoustic wave resonator according to various exemplary embodiments of the present invention.
  • FIG. 23 is a schematic cross-sectional view along line OC in FIG. 2 of a bulk acoustic wave resonator according to another exemplary embodiment of the present invention.
  • the material can be selected from molybdenum, ruthenium, gold, aluminum, magnesium, tungsten, copper, titanium, iridium, osmium, chromium or the composite of the above metals or their alloys.
  • the acoustic mirror can be a cavity, or a Bragg reflection layer and other equivalent forms. In the embodiment shown in the present invention, a cavity is used.
  • the support layer, the material may be a dielectric material such as SiN, SiO 2 , etc., the material of which is different from the material of the release material layer.
  • Substrate, optional materials are single crystal silicon, gallium nitride, gallium arsenide, sapphire, quartz, silicon carbide, diamond, etc.
  • Bonding layer such as silicon dioxide, silicon nitride and other materials.
  • Top electrode the material can be selected from molybdenum, ruthenium, gold, aluminum, magnesium, tungsten, copper, titanium, iridium, osmium, chromium or the composite of the above metals or their alloys.
  • the top and bottom electrode materials are generally the same, but can also be different.
  • the material can be selected from molybdenum, ruthenium, gold, aluminum, magnesium, tungsten, copper, titanium, iridium, osmium, chromium or a composite of the above metals or their alloys.
  • Passivation layer generally a dielectric material, such as silicon dioxide, aluminum nitride, silicon nitride, etc.
  • Lithium oxide and other materials can also contain rare earth element doped materials with a certain atomic ratio of the above materials, such as doped aluminum nitride, and doped aluminum nitride 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 (T
  • the dielectric layer can be silicon dioxide, aluminum nitride, silicon nitride, etc.
  • Air gap or dielectric layer the material of the dielectric layer can be silicon dioxide, aluminum nitride, silicon nitride, etc.
  • Filling layer the material of which can be SiN, SiO 2 and other dielectric materials.
  • Auxiliary substrate, optional materials are single crystal silicon, gallium nitride, gallium arsenide, sapphire, quartz, silicon carbide, diamond, etc.
  • the material may be a dielectric material such as SiN, SiO 2 or the like.
  • FIG 3 is a schematic cross-sectional view of a bulk acoustic wave resonator according to an exemplary embodiment of the present invention, which is one parallel to the thickness direction of the resonator through the non-electrically connected end of the bottom electrode 10 and the non-electrically connected end of the top electrode 50 Sectional view.
  • the BAW resonator mainly includes: a substrate 40 , a support layer 30 , an acoustic mirror 20 , a bottom electrode 10 , a piezoelectric layer 70 and a top electrode 50 .
  • the support layer 30 is disposed on the substrate 40 for supporting the resonant structure of the BAW resonator.
  • a cavity is formed in the support layer 30 , which cavity constitutes the acoustic mirror 20 .
  • the bottom electrode 10 is disposed on the lower surface of the piezoelectric layer 70
  • the top electrode 50 is disposed on the upper surface of the piezoelectric layer 40 , so that the piezoelectric layer 70 is sandwiched between the bottom electrode 10 and the top electrode 50 .
  • the support layer 30 (ie, the support structure) is disposed between the lower surface of the piezoelectric layer 70 and the upper surface of the substrate 40 , and the piezoelectric layer 70 and the substrate 40 are generally arranged in parallel.
  • the bottom side of the cavity or the cavity of the acoustic mirror is defined by the support layer, but the present invention is not limited thereto, and the bottom side of the cavity may also be defined by the substrate 40 . These are all within the protection scope of the present invention.
  • a portion of the outer end of the non-electrically connected end of the bottom electrode 10 is covered by the support layer 30, and at least a portion of the piezoelectric layer above the non-electrically connected end of the bottom electrode 10 is displaced and at least a part of the upper surface of the non-electrically connecting end of the bottom electrode 10 is flush with the upper surface of the supporting layer 30 .
  • the area shown by C1 is the area where the upper part of the acoustic mirror 20 only covers the bottom electrode 10 or only the bottom electrode 10 , and in the area C1 , the piezoelectric layer is removed.
  • the outer end of the piezoelectric layer 70 is inside the boundary of the acoustic mirror 20 .
  • the width of the C1 region in FIG. 3 is the distance in the horizontal direction between the outer end of the piezoelectric layer 70 at the non-electrically connected end of the bottom electrode 10 and the boundary of the acoustic mirror 20 . greater than a quarter of the wavelength of the resonator, or greater than 0.5 ⁇ m.
  • the end faces of the piezoelectric layers are inclined planes.
  • the present invention is not limited to this, and the end face may also be a vertical face, for example, see FIGS. 9 and 10 .
  • the Lamb wave transmitted in the bottom electrode 10 can be further diffused outward to the support layer 30 , effectively reducing the above-mentioned Lamb wave caused by the bottom electrode 10 .
  • the parasitic mode caused by the return can effectively improve the performance of the device.
  • FIG. 5 is a schematic cross-sectional view of a bulk acoustic wave resonator along line OC' in FIG. 2 according to another exemplary embodiment of the present invention.
  • the difference between the embodiment shown in FIG. 5 and FIG. 3 is that in FIG. 5 , the piezoelectric layers outside the effective area are not all removed as shown in FIG. 3 , but are removed from the upper surface of the piezoelectric layer 70 . A portion of the thickness is removed to form the shape of a step 71 on the upper surface of the piezoelectric layer 70 .
  • the structure shown in FIG. 5 has more sound wave leakage due to less removal, and the Q value is relatively low, but the support is more stable, so the reliability is better.
  • the other structures shown in FIG. 5 are basically the same as those shown in FIG. 3 , and will not be repeated here.
  • FIG. 6 is a schematic cross-sectional view of a bulk acoustic wave resonator along line OC' in FIG. 2 according to another exemplary embodiment of the present invention.
  • the difference between the embodiment shown in FIG. 6 and FIG. 5 is that, in FIG. 6 , the upper surface of the piezoelectric layer outside the effective area is removed by a part of its thickness to form a plurality of steps 71 and 72 , not as Figure 5 shows only one step.
  • the structure shown in Figure 6 has a stepped structure and features with more removal, resulting in less acoustic leakage and a relatively high Q value; compared with the structure shown in Figure 3, the support is more stable, so Reliability is better.
  • the other structures shown in FIG. 6 are basically the same as those shown in FIG. 3 and FIG. 5 , and will not be repeated here.
  • FIG. 7 is a schematic cross-sectional view along line OC' in FIG. 2 of a bulk acoustic wave resonator according to another exemplary embodiment of the present invention.
  • the difference between the embodiment shown in FIG. 7 and FIG. 3 is that in FIG. 7 , the piezoelectric layers outside the effective area are not all removed as shown in FIG. 3 , but are removed from the upper surface of the piezoelectric layer 70 . A portion is removed to form a recess 73 .
  • the inner edge of the recess 73 is flush with the outer edge of the non-electrically connected end of the top electrode 50 .
  • the support is further improved for the structure shown in FIG. 5, so the reliability is better; at the same time, the characteristics of the concave structure bring less sound wave leakage, and the Q value is relatively high.
  • the other structures shown in FIG. 7 are basically the same as those shown in FIG. 3 , and will not be repeated here.
  • FIG. 8 is a schematic cross-sectional view along line OC' in FIG. 2 of a bulk acoustic wave resonator according to another exemplary embodiment of the present invention.
  • the difference between the embodiment shown in FIG. 8 and FIG. 7 is that in FIG. 8 , the concave portion 73 is filled with a medium 74 , and in addition, the outer edge of the non-electrically connected end of the top electrode in FIG. 8 is in the horizontal direction of the groove. between the inner and outer edges.
  • the support is further improved for the structure shown in FIG. 7, so the reliability is better.
  • the other structures shown in FIG. 8 are basically the same as those shown in FIG. 3 and FIG. 7 , and will not be repeated here.
  • FIG. 9 is a schematic cross-sectional view along line OC' in FIG. 2 of a bulk acoustic wave resonator according to another exemplary embodiment of the present invention.
  • the difference between the embodiment shown in FIG. 9 and FIG. 3 is that, in FIG. 9 , the end face of the piezoelectric layer is a vertical face 75 .
  • the other structures shown in FIG. 9 are basically the same as those shown in FIG. 3 , and will not be repeated here.
  • FIG. 10 is a schematic cross-sectional view of a bulk acoustic wave resonator along line OC' in FIG. 2 according to another exemplary embodiment of the present invention.
  • the difference between the embodiment shown in FIG. 10 and FIG. 9 is that, in FIG. 10 , a filling layer or a support layer 89 is further provided on the outside of the end face of the piezoelectric layer, which is connected to the piezoelectric layer 70 at the non-electrical connection end of the bottom electrode. Arranged on the same level.
  • the other structures shown in FIG. 10 are basically the same as those shown in FIG. 3 and FIG. 9 , and will not be repeated here.
  • FIG. 11 is a schematic cross-sectional view along line OC' in FIG. 2 of a bulk acoustic wave resonator according to another exemplary embodiment of the present invention.
  • the difference between the embodiment shown in FIG. 11 and FIG. 3 is that, in FIG. 11 , the non-electrically connected end of the top electrode 50 extends straight to the outside of the outer end of the piezoelectric layer, so that the top electrode is on the outside of the piezoelectric layer 70
  • An air gap 76 is formed between 50 and the non-electrically connected end of the bottom electrode 10 .
  • the structure shown in FIG. 11 forms an air gap 76 that can further reduce the sound wave leakage and improve the Q value.
  • the other structures shown in FIG. 11 are basically the same as those shown in FIG. 3 , and will not be repeated here.
  • FIG. 12 is a schematic cross-sectional view of a bulk acoustic wave resonator along line OC' in FIG. 2 according to another exemplary embodiment of the present invention.
  • the difference between the embodiment shown in FIG. 12 and FIG. 3 is that in FIG. 12 , the non-electrically connected end of the top electrode 50 is formed with a cantilever structure, so that the non-electrically connected end of the top electrode and the upper surface of the piezoelectric layer 70 are formed.
  • An air gap 77 is formed therebetween.
  • the structure shown in FIG. 12 forms an air gap 77 that can further reduce the sound wave leakage and improve the Q value.
  • the other structures shown in FIG. 12 are basically the same as those shown in FIG. 3 , and will not be repeated here.
  • FIG. 13 is a schematic cross-sectional view of a bulk acoustic wave resonator along line OC' in FIG. 2 according to another exemplary embodiment of the present invention.
  • the difference between the embodiment shown in FIG. 13 and FIG. 8 is that, in FIG. 13 , the depression on the upper surface of the piezoelectric layer 70 is provided in the horizontal direction inside the non-point connection end of the top electrode 50 , and in FIG. 13 , the cross section of the depression is rectangular, while in FIG. 8 it is trapezoidal.
  • the recesses are also filled with dielectrics, such as SiO 2 , Si 3 N 4 , BPSG, and the like.
  • the other structures shown in FIG. 13 are basically the same as those shown in FIG. 3 and FIG. 8 , and will not be repeated here.
  • FIG. 14 is a schematic cross-sectional view of a bulk acoustic wave resonator along line OC' in FIG. 2 according to another exemplary embodiment of the present invention.
  • the difference between the embodiment shown in FIG. 14 and FIG. 8 is that in FIG. 14 , a depression 81 is provided on the lower surface of the piezoelectric layer 70 , and in addition, in FIG. 14 , the cross section of the depression is rectangular, while in FIG. 8 is trapezoidal.
  • the recesses may be air gaps, or may be filled with dielectrics, such as SiO 2 , Si 3 N 4 , BPSG, and the like.
  • the other structures shown in FIG. 14 are basically the same as those shown in FIG. 3 and FIG. 8 , and will not be repeated here.
  • FIG. 15 is a schematic cross-sectional view of a bulk acoustic wave resonator along line OC' in FIG. 2 according to another exemplary embodiment of the present invention.
  • the embodiment shown in FIG. 15 differs from FIG. 8 in that, in FIG. 15 , the piezoelectric layer 70 is provided with through holes 83 therethrough.
  • the through hole may be an air gap, or may be filled with a medium, such as SiO 2 , Si 3 N 4 , BPSG, or the like.
  • the other structures shown in FIG. 15 are basically the same as those shown in FIG. 3 and FIG. 8 , and will not be repeated here.
  • FIG. 16 is a schematic cross-sectional view of a bulk acoustic wave resonator along line OC' in FIG. 2 according to another exemplary embodiment of the present invention.
  • the difference between the embodiment shown in FIG. 16 and FIG. 14 is that, in FIG. 16 , the lower surface of the piezoelectric layer 70 is provided with a depression 85 extending outwards instead of just the depression 81 in FIG. 14 .
  • the bottom electrode is The non-electrical connection end of 10 is a straight portion and extends over part of the recess 85 .
  • the recesses 85 may be in the form of air gaps, and may also be filled with materials such as SiO 2 , Si 3 N 4 , and BPSG.
  • the further outward extension of the recess 85 shown in FIG. 16 can further reduce the acoustic leakage and increase the Q value.
  • the other structures shown in FIG. 16 are basically the same as those shown in FIG. 3 and FIG. 14 , and will not be repeated here.
  • the non-electrical connection end of the bottom electrode 10 is a straight portion, and the bottom electrode is a straight electrode, but the present invention is not limited thereto.
  • FIG. 17 is a schematic cross-sectional view along line OC' in FIG. 2 of a bulk acoustic wave resonator according to another exemplary embodiment of the present invention.
  • the difference between the embodiment shown in FIG. 17 and FIG. 14 is that, in FIG. 17 , the lower surface of the piezoelectric layer 70 is provided with a recess 84 , and the non-electric connection end of the bottom electrode 10 fills the recess 84 .
  • the structure shown in FIG. 17 has higher mechanical stability and better reliability.
  • the other structures shown in FIG. 17 are basically the same as those shown in FIG. 3 and FIG. 14 , and will not be repeated here.
  • FIG. 18 is a schematic cross-sectional view of a bulk acoustic wave resonator along line OC' in FIG. 2 according to another exemplary embodiment of the present invention.
  • the lower surface of the piezoelectric layer 70 is provided with a dielectric layer 87 that fills the depression and covers part of the surface of the piezoelectric layer 70 , such as SiO 2 , Si 3 N 4 , BPSG and other materials, the non-electrical connection end of the bottom electrode 10 covers the dielectric layer 87 .
  • the structure shown in Figure 18 has higher mechanical stability and better reliability; compared with the structure shown in Figure 17, the parasitic mode caused by the electrode bending is smaller, which is isolated by the dielectric layer. Electrical response in parasitic mode.
  • the other structures shown in FIG. 18 are basically the same as those shown in FIG. 3 and FIG. 17 , and will not be repeated here.
  • FIG. 19 is a schematic cross-sectional view of a bulk acoustic wave resonator along line OC' in FIG. 2 according to another exemplary embodiment of the present invention.
  • the difference between the embodiment shown in FIG. 19 and FIG. 16 is that, in FIG. 19 , the lower surface of the piezoelectric layer 70 is provided with a dielectric layer 88 , such as SiO, which fills the depression in FIG. 16 and covers part of the surface of the piezoelectric layer 70 2.
  • Materials such as Si 3 N 4 , BPSG, etc., the non-electric connection end of the bottom electrode 10 covers the dielectric layer 88 .
  • the structure shown in FIG. 19 has higher mechanical stability and better reliability than the structure shown in FIG. 16 .
  • the other structures shown in FIG. 19 are basically the same as those shown in FIG. 3 and FIG. 16 , and will not be repeated here.
  • FIG. 20 is a schematic cross-sectional view of a bulk acoustic wave resonator along line OB in FIG. 2 according to an exemplary embodiment of the present invention.
  • FIG. 20 shows a schematic cross-sectional view parallel to the thickness direction of the resonator through the non-electrically connected end of the bottom electrode 10 and the electrical connection end of the top electrode 50 .
  • the upper and lower surfaces of the piezoelectric layer 70 are both flat surfaces and extend outside the non-electrical connection end of the bottom electrode 10 .
  • FIG. 21 is a schematic cross-sectional view of a bulk acoustic wave resonator along line OB in FIG. 2 according to an exemplary embodiment of the present invention.
  • FIG. 21 shows a schematic cross-sectional view through the non-electrically connected end of the bottom electrode 10 and the electrical connection end of the top electrode 50 parallel to the thickness direction of the resonator. As shown in FIG.
  • the electrical connection terminal of the top electrode 50 extends horizontally to the outside of the piezoelectric layer.
  • the air gap 91 may be replaced by a filled insulating medium.
  • FIG. 22 is a schematic cross-sectional view of a bulk acoustic wave resonator along line OB in FIG. 2 according to an exemplary embodiment of the present invention.
  • FIG. 22 shows a schematic cross-sectional view through the non-electrically connected end of the bottom electrode 10 and the electrical connection end of the top electrode 50 parallel to the thickness direction of the resonator. As shown in FIG.
  • an air gap 92 is defined between the electrically connected end of the top electrode 50 and the non-electrically connected end of the bottom electrode 10 and the upper surface of the support layer 30 .
  • a part of the electrical connection end of the top electrode 50 forms a gap between the thickness direction of the resonator and the upper surface of the piezoelectric layer 70 .
  • the air gap 92 may be replaced by a filled insulating medium.
  • FIG. 23 is a schematic cross-sectional view along line OC in FIG. 2 of a bulk acoustic wave resonator according to another exemplary embodiment of the present invention.
  • FIG. 23 shows a schematic cross-sectional view parallel to the thickness direction of the resonator through the electrical connection end of the bottom electrode 10 and the non-electrical connection end of the top electrode 50 .
  • a part of the outer end of the electrical connection end of the bottom electrode 10 is covered by the support layer 30 , at least a part of the piezoelectric layer at the electrical connection end of the bottom electrode 10 is removed, and the upper surface of the electrical connection end of the bottom electrode 10 is removed.
  • the resonator also includes a bottom electrode lead-out portion 61 And at least the passivation layer 62 covering the top electrode 50, the bottom electrode lead-out portion 61 covers at least a part of the upper surface of the electrical connection end of the bottom electrode 10 and the inner end of the bottom electrode lead-out portion 61 is at least above the piezoelectric layer 70 and horizontally. The direction is outside the outer end of the top electrode 50 .
  • the bottom electrode lead-out portion 61 extends toward the center of the resonator, which is beneficial to enhance the problem of the weakening of the mechanical support structure caused by the etching of the single crystal piezoelectric layer 70 .
  • Step 1 As shown in FIG. 4A , a POI (Piezoelectrics on Insulator, monocrystalline piezoelectric layer on an insulator) wafer is provided, and the POI wafer includes an auxiliary substrate 101 and an insulating layer 102 disposed on the auxiliary substrate 101 and the single crystal piezoelectric layer 70 disposed on the insulating layer 102, the side of the piezoelectric layer 70 facing away from the insulating layer 102 is the first side of the piezoelectric layer.
  • the POI wafer includes an auxiliary substrate 101 and an insulating layer 102 disposed on the auxiliary substrate 101 and the single crystal piezoelectric layer 70 disposed on the insulating layer 102, the side of the piezoelectric layer 70 facing away from the insulating layer 102 is the first side of the piezoelectric layer.
  • Step 2 As shown in FIG. 4B , the bottom electrode 10 is formed on the first side of the single crystal piezoelectric layer 70 .
  • Step 3 As shown in FIG. 4C , a patterned release material layer 20' is formed on the upper surface of the bottom electrode 10, which is used to form the acoustic mirror 20.
  • Step 4 As shown in FIG. 4D, a support layer 30 covering the release material layer 20', the bottom electrode 10 and the piezoelectric layer 70 is formed on the structure shown in FIG. 4C. ) process to planarize the outer surface of the support layer 30 .
  • Step 5 As shown in FIG. 4E , a substrate 40 is provided, and a bonding layer 41 is provided on one side of the substrate 40 .
  • Step 6 As shown in FIG. 4F , the flat surface of the support layer 30 is bonded and connected to the bonding layer 41 .
  • the support layer 30 may be bonded with the substrate 10 by physical or chemical means, or may be directly bonded without the bonding layer 41, but a chemical bond may be formed between the substrate 40 and the support layer 30, or the surface may be polished to the surface. Physical bonds are formed by intermolecular forces at very low roughness.
  • Step 7 As shown in FIG. 4G , the auxiliary substrate 101 and the insulating layer 102 are removed to expose the second side of the piezoelectric layer 70 .
  • the etching processes of the auxiliary substrate 101 and the insulating layer 102 are very different.
  • the auxiliary substrate 101 is silicon and the insulating layer 102 is silicon dioxide.
  • the removal process of the insulating layer 102 is mild, and the damage to the other surface of the piezoelectric single crystal thin film during the process of removing the auxiliary substrate 101 is reduced or even avoided.
  • Step 8 As shown in FIG. 4H , a top electrode 50 is formed on the second side of the single crystal piezoelectric layer 70 .
  • Step 9 As shown in FIG. 4I, the piezoelectric layer 70 of the structure shown in FIG. 4H is etched to form the piezoelectric layer 70 shown in FIG. 4I. In Fig. 4I, the release holes for releasing the release material layer 20' are not shown.
  • Step 10 As shown in FIG. 4J, a bottom electrode lead-out portion 60 is provided on the electrical connection end of the bottom electrode of the structure shown in FIG. 4I.
  • Step 11 As shown in Fig. 4K, release the release material layer 20' to form an acoustic mirror cavity of the resonator, thereby forming a bulk acoustic wave resonator corresponding to the structure shown in Fig. 3 .
  • upper and lower are relative to the bottom surface of the base of the resonator.
  • the side close to the bottom surface is the lower side, and the side away from the bottom surface is the upper side.
  • each numerical range except that it is clearly indicated that it does not include the endpoint value, can be the endpoint value, and can also be the median value of each numerical range, and these are all within the protection scope of the present invention. .
  • the center of the effective area of the resonator (the overlapping area of the piezoelectric layer, the top electrode, the bottom electrode and the acoustic mirror in the thickness direction of the resonator constitutes the effective area) (ie, the center of the effective area).
  • the side or end of a component close to the center of the effective area is the inner or inner end
  • the side or end of the component away from the center of the effective area is the outer or outer end.
  • BAW resonators may be used to form filters or electronic devices.
  • a bulk acoustic wave resonator comprising:
  • a support layer is arranged between the substrate and the resonant structure, and the piezoelectric layer is a single crystal piezoelectric layer arranged substantially parallel to the substrate;
  • a part of the outer end of the non-electrically connected end of the bottom electrode is covered by the support layer, and at the bottom electrode At least a portion of the piezoelectric layer of the non-electrical connection end is removed, and at least a portion of the upper surface of the non-electrical connection end of the bottom electrode is flush with the upper surface of the support layer.
  • the outer end of the piezoelectric layer is inside the boundary of the acoustic mirror.
  • the distance between the outer end of the piezoelectric layer and the boundary of the acoustic mirror in the horizontal direction is greater than a quarter of the wavelength of the resonator, or greater than 0.5 ⁇ m .
  • the end face of the outer end of the piezoelectric layer is a vertical plane or an outwardly inclined inclined plane.
  • the resonator further includes a filling layer, and the filling layer is arranged in the same layer as the piezoelectric layer at the non-electrical connection end of the bottom electrode.
  • the non-electrically connected end of the top electrode is a straight end and is horizontally outside the end of the piezoelectric layer;
  • the non-electrically connected end of the top electrode has a cantilever structure.
  • a single or a plurality of stepped portions are formed on the upper surface of the piezoelectric layer;
  • a single or a plurality of stepped portions are formed on the lower surface of the piezoelectric layer.
  • a depression is formed on the upper surface or the lower surface of the piezoelectric layer
  • the piezoelectric layer is provided with a through hole at the non-electrical connection end of the bottom electrode.
  • the recessed portion or the through hole is filled with a dielectric material.
  • the end face of the non-electrically connected end of the top electrode is located between the inner side and the outer side of the recess or through hole in the horizontal direction;
  • the recessed portion or the through hole is located outside the non-electrode connection end of the top electrode in the horizontal direction;
  • the recessed portion or the through hole is located inside the non-electrode connection end of the top electrode in the horizontal direction.
  • a part of the outer end of the electrical connection end of the bottom electrode is covered by the support layer, and the electrical connection end of the bottom electrode is partially covered by the support layer.
  • at least a portion of the piezoelectric layer of the terminal is removed, and at least a portion of the upper surface of the electrical connection terminal of the bottom electrode is flush with the upper surface of the support layer;
  • the outer end of the piezoelectric layer is located inside the boundary of the acoustic mirror
  • the resonator further includes a bottom electrode lead-out portion and a passivation layer covering at least the top electrode, the bottom electrode lead-out portion covers at least a part of the upper surface of the electrical connection end of the bottom electrode, and the inner end of the bottom electrode lead-out portion is at least in The upper side of the piezoelectric layer is outside the outer end of the top electrode in the horizontal direction.
  • the bottom electrode is a flat electrode.
  • a recessed portion is formed on the lower surface of the piezoelectric layer at the non-electrically connected end of the bottom electrode, and the non-electrically connected end of the bottom electrode includes a portion located in the recessed portion;
  • a recessed portion is formed on the lower surface of the piezoelectric layer, and a recessed filling medium is further included between the non-electrically connected end of the bottom electrode and the piezoelectric layer layer, the recessed filling dielectric layer fills the recessed portion and covers a portion of the lower surface of the piezoelectric layer, and the non-electrically connected end of the bottom electrode covers the filling dielectric layer;
  • a step portion is formed on the lower surface of the piezoelectric layer at the non-electrically connected end of the bottom electrode, and a step filling medium is further included between the non-electrically connected end of the bottom electrode and the piezoelectric layer
  • the step-filled dielectric layer fills the stepped portion and covers a part of the lower surface of the piezoelectric layer, and the non-electrically connected end of the bottom electrode covers the step-filled dielectric layer.
  • the upper and lower surfaces of the piezoelectric layer are both flat surfaces and extends to the outside of the non-electrical connection end of the bottom electrode.
  • the electrical connection end of the top electrode straddles the non-electrical connection end of the bottom electrode in the horizontal direction.
  • the electrical connection end of the top electrode extends horizontally to the outside of the piezoelectric layer;
  • a portion of the electrical connection end of the top electrode forms a gap between the thickness direction of the resonator and the upper surface of the piezoelectric layer.
  • a filter comprising the bulk acoustic wave resonator of any one of 1-16.
  • An electronic device comprising the bulk acoustic wave resonator according to any one of 1-16, or the filter according to 17.
  • the electronic equipment here includes but is not limited to intermediate products such as RF front-end, filter and amplifier modules, and terminal products such as mobile phones, WIFI, and drones.

Landscapes

  • Physics & Mathematics (AREA)
  • Acoustics & Sound (AREA)
  • Engineering & Computer Science (AREA)
  • Manufacturing & Machinery (AREA)
  • Piezo-Electric Or Mechanical Vibrators, Or Delay Or Filter Circuits (AREA)

Abstract

La présente invention concerne un résonateur acoustique en volume, comprenant un substrat, une électrode supérieure, une couche piézoélectrique, une électrode inférieure et un miroir acoustique. Une couche de support est disposée entre le substrat et une structure résonante, et la couche piézoélectrique est une couche piézoélectrique monocristalline disposée à peu près parallèle au substrat. Dans une première section transversale qui est parallèle à la direction de l'épaisseur d'un résonateur et passe à travers une extrémité non connectée électriquement de l'électrode inférieure et une extrémité non connectée électriquement de l'électrode supérieure, une partie d'une extrémité externe de l'extrémité non connectée électriquement de l'électrode inférieure est recouverte par la couche de support, au moins une partie de la couche piézoélectrique au niveau de l'extrémité non connectée électriquement de l'électrode inférieure est retirée, et au moins une partie d'une surface supérieure de l'extrémité non connectée électriquement de l'électrode inférieure affleure une surface supérieure de la couche de support. La présente invention concerne en outre un filtre et un dispositif électronique.
PCT/CN2022/070884 2021-02-01 2022-01-10 Résonateur acoustique en volume, filtre et dispositif électronique WO2022161142A1 (fr)

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CN202110139663.1A CN114844481A (zh) 2021-02-01 2021-02-01 体声波谐振器、滤波器及电子设备
CN202110139663.1 2021-02-01

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Cited By (1)

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EP4354730A4 (fr) * 2022-08-26 2024-06-26 JWL (Zhejiang) Semiconductor Co., Ltd. Ensemble résonateur, résonateur acoustique en volume, filtre et dispositif électronique

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CN111010100A (zh) * 2019-03-02 2020-04-14 天津大学 压电层带凹陷结构的体声波谐振器、滤波器及电子设备
CN111262547A (zh) * 2019-12-31 2020-06-09 诺思(天津)微系统有限责任公司 体声波谐振器、mems器件、滤波器和电子设备
CN111682101A (zh) * 2020-05-20 2020-09-18 华南理工大学 一种柔性fbar滤波器的制造方法
CN111756351A (zh) * 2020-04-03 2020-10-09 诺思(天津)微系统有限责任公司 体声波谐振器及其制造方法、滤波器和电子设备
CN113497593A (zh) * 2020-04-08 2021-10-12 诺思(天津)微系统有限责任公司 单晶体声波谐振器、滤波器及电子设备

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Publication number Priority date Publication date Assignee Title
CN111010100A (zh) * 2019-03-02 2020-04-14 天津大学 压电层带凹陷结构的体声波谐振器、滤波器及电子设备
CN111262547A (zh) * 2019-12-31 2020-06-09 诺思(天津)微系统有限责任公司 体声波谐振器、mems器件、滤波器和电子设备
CN111756351A (zh) * 2020-04-03 2020-10-09 诺思(天津)微系统有限责任公司 体声波谐振器及其制造方法、滤波器和电子设备
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CN111682101A (zh) * 2020-05-20 2020-09-18 华南理工大学 一种柔性fbar滤波器的制造方法

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP4354730A4 (fr) * 2022-08-26 2024-06-26 JWL (Zhejiang) Semiconductor Co., Ltd. Ensemble résonateur, résonateur acoustique en volume, filtre et dispositif électronique

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