WO2023202548A9 - Résonateur à ondes acoustiques de volume, procédé de préparation de résonateur à ondes acoustiques de volume et dispositif électronique - Google Patents

Résonateur à ondes acoustiques de volume, procédé de préparation de résonateur à ondes acoustiques de volume et dispositif électronique Download PDF

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WO2023202548A9
WO2023202548A9 PCT/CN2023/088850 CN2023088850W WO2023202548A9 WO 2023202548 A9 WO2023202548 A9 WO 2023202548A9 CN 2023088850 W CN2023088850 W CN 2023088850W WO 2023202548 A9 WO2023202548 A9 WO 2023202548A9
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electrode
substrate
layer
groove
acoustic wave
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PCT/CN2023/088850
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Chinese (zh)
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WO2023202548A1 (fr
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焦卓凡
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京东方科技集团股份有限公司
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Publication of WO2023202548A1 publication Critical patent/WO2023202548A1/fr
Publication of WO2023202548A9 publication Critical patent/WO2023202548A9/fr

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    • 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
    • H03H9/02007—Details of bulk acoustic wave devices
    • H03H9/02086—Means for compensation or elimination of undesirable effects
    • H03H9/02125—Means for compensation or elimination of undesirable effects of parasitic elements
    • 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
    • H03H9/02—Details
    • H03H9/02007—Details of bulk acoustic wave devices
    • H03H9/02015—Characteristics of piezoelectric layers, e.g. cutting angles
    • 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
    • H03H9/02007—Details of bulk acoustic wave devices
    • H03H9/02086—Means for compensation or elimination of undesirable effects
    • H03H9/02102—Means for compensation or elimination of undesirable effects of temperature influence
    • 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
    • H03H9/125—Driving means, e.g. electrodes, coils
    • H03H9/13—Driving means, e.g. electrodes, coils for networks consisting of piezoelectric or electrostrictive materials
    • 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
    • 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
    • H03H9/171—Constructional features of resonators consisting of piezoelectric or electrostrictive material having a single resonator implemented with thin-film techniques, i.e. of the film bulk acoustic resonator [FBAR] type
    • 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
    • H03H2003/023—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 the resonators or networks being of the membrane type

Definitions

  • the present disclosure belongs to the technical field of bulk acoustic wave resonators, and specifically relates to a bulk acoustic wave resonator, a preparation method of a bulk acoustic wave resonator, and electronic equipment.
  • the traditional Bulk Acoustic Wave (BAW) resonator is a three-layer composite structure composed of a first electrode, a piezoelectric layer and a second electrode. It has the advantages of small size and good performance.
  • the materials used to prepare BAW resonators are negative temperature coefficient materials (for example, the materials of the piezoelectric layer are aluminum nitride AlN, zinc oxide ZnO, etc., and the electrode materials are molybdenum Mo, aluminum Al, etc.), resulting in BAW resonance
  • the resonant frequency of the device is prone to drift with changes in external temperature.
  • the present disclosure provides a bulk acoustic wave resonator, a preparation method of the bulk acoustic wave resonator, and electronic equipment.
  • the bulk acoustic wave resonator includes a first substrate, a first electrode, a piezoelectric layer, a second electrode and a temperature compensation layer; the first substrate has a first groove;
  • the second electrode, the piezoelectric layer and the first electrode are arranged in sequence along a side away from the first substrate; the groove direction of the first groove is toward the second electrode, and the The orthographic projection of the first groove on the piezoelectric layer covers the orthographic projection of the second electrode on the piezoelectric layer; the orthographic projection of the first electrode and the second electrode on the piezoelectric layer Orthographic projections overlap at least partially;
  • the temperature compensation layer is disposed on a side of the first electrode close to the first substrate, and the temperature compensation layer The degree compensation layer is in contact with the piezoelectric layer;
  • the side of the first electrode facing away from the first substrate has at least one step structure; each step structure in the at least one step structure includes a protruding structure and is disposed close to the protruding structure.
  • a second groove on one side of the central area of the first electrode; both the second groove and the protruding structure are annular.
  • the first electrode includes a plurality of the ladder structures, and the plurality of ladder structures are nested.
  • the plurality of ladder structures include a first ladder structure and a second ladder structure; the protruding structure of the first ladder structure is an annular edge portion of the first electrode, and the second ladder structure of the first ladder structure is an annular edge portion of the first electrode.
  • the groove is located inside the convex structure of the first ladder structure; the convex structure of the second ladder structure is located inside the second groove of the first ladder structure, and the second groove of the second ladder structure is located inside the convex structure of the first ladder structure.
  • the interior of the raised structure of the second stepped structure; and the raised structure of the first stepped structure is spaced from the second groove of the first stepped structure by a first step, the second groove of the first stepped structure
  • a second step is spaced apart from the convex structure of the second step structure, and both the first step and the second step are annular.
  • the convex structure of the first ladder structure and the convex structure of the second ladder structure have the same height in a direction perpendicular to the first substrate;
  • the second groove and the second groove of the second stepped structure have the same height in a direction perpendicular to the first substrate; and/or the first step and the second step have the same height in a direction perpendicular to the first substrate.
  • the heights of the first substrate in the direction are the same.
  • orthographic projections of the outline of the second groove and the outline of the protruding structure on the first substrate are both regular polygons.
  • the regular polygons include regular quadrilaterals, regular pentagons and regular hexagons.
  • the ratio of the thickness of the protruding structure to the thickness of the first electrode is between 9/20 and 11/20; and/or,
  • the ratio of the thickness of the second groove to the thickness of the first electrode is between 1/5 and 3/10.
  • the material of the piezoelectric layer includes single crystal aluminum nitride.
  • the material of the temperature compensation layer is a material with a positive temperature coefficient.
  • the positive temperature coefficient material includes silicon dioxide.
  • the thickness of the temperature compensation layer meets at least one of the following conditions:
  • the ratio of the thickness of the temperature compensation layer to the thickness of the second electrode is between 19/20 and 21/20;
  • the ratio of the thickness of the temperature compensation layer to the thickness of the first electrode is between 9/20 and 11/20;
  • the ratio of the thickness of the temperature compensation layer to the thickness of the piezoelectric layer is between 1/20 and 3/20.
  • the temperature compensation layer is disposed between the piezoelectric layer and the first electrode; or, the temperature compensation layer is disposed between the piezoelectric layer and the second electrode.
  • an orthographic projection of the temperature compensation layer on the piezoelectric layer at least partially overlaps an orthographic projection of the first electrode and the second electrode on the piezoelectric layer.
  • the piezoelectric layer includes an epitaxial growth layer and a seed layer sequentially disposed along a side of the second electrode facing away from the first substrate.
  • a passivation layer disposed on a side of the first electrode facing away from the first substrate is further included.
  • the present disclosure also provides a method for preparing a bulk acoustic wave resonator, including:
  • the second substrate on which the piezoelectric layer and the second electrode are formed is bonded to the first substrate; the groove direction of the first groove is toward the second electrode, and the The orthographic projection of the first groove on the piezoelectric layer covers the orthographic projection of the second electrode on the piezoelectric layer;
  • the second substrate is removed, and a first electrode is formed on a side of the piezoelectric layer facing away from the first substrate; forming the first electrode includes:
  • a first electrode material layer is formed, and a first electrode having at least one ladder structure is formed through a patterning process; wherein each of the at least one ladder structure includes a protrusion structure and a second Groove; forming the first electrode with at least one step structure through a patterning process includes: forming the protruding structure on the side of the first electrode facing away from the first substrate; forming the protruding structure close to the first substrate.
  • the second groove is formed on one side of the center area of an electrode; both the second groove and the protruding structure are annular;
  • the preparation method also includes:
  • a temperature compensation layer is formed on a side of the first electrode close to the first substrate; the temperature compensation layer is in contact with the piezoelectric layer.
  • forming the first electrode having at least one ladder structure through a patterning process includes forming the first electrode having a plurality of ladder structures through a patterning process, such that a plurality of the ladder structures are nested.
  • forming the piezoelectric layer includes:
  • a first material layer is formed on the second substrate, and the first material layer serves as a seed layer;
  • a second material layer is formed on the side of the seed layer facing away from the second substrate, so that the second material layer grows epitaxially under the action of the first material layer to form The epitaxial growth layer to form the piezoelectric layer stacked by the seed layer and the epitaxial growth layer.
  • the formed first material layer and the second material layer are made of single crystal aluminum nitride.
  • the step of forming the temperature compensation layer includes any of the following methods:
  • the temperature compensation layer is formed between the piezoelectric layer and the second electrode.
  • the present disclosure also provides an electronic device, including the bulk acoustic wave resonator as described in the first aspect.
  • FIG. 1 and 2 are structural cross-sectional views of a bulk acoustic wave resonator provided by embodiments of the present disclosure
  • 3a and 3b are structural cross-sectional views of the bulk acoustic wave resonator provided by embodiments of the present disclosure
  • FIGS. 4a to 4d are top views of the bulk acoustic wave resonator provided by embodiments of the present disclosure.
  • Figure 5 is a schematic diagram of a response simulation curve of the real part of the input impedance of the raised structure provided by the embodiment of the present disclosure as the frequency changes;
  • Figure 6 is a schematic diagram of a response simulation curve of the real part of the input impedance of the second groove as a function of frequency provided by an embodiment of the present disclosure
  • Figure 7 is a side view of the specific structure of the piezoelectric layer provided by an embodiment of the present disclosure.
  • Figure 8 is a flow chart of a method for preparing a bulk acoustic wave resonator provided by an embodiment of the present disclosure
  • 9a to 9f are schematic diagrams of intermediate structures formed by each step in the preparation method of a bulk acoustic wave resonator provided by embodiments of the present disclosure.
  • first direction X, the second direction Y, and the third direction Z intersect each other.
  • first direction X and the third direction X are perpendicular to each other on the plane where the first substrate is located, the first direction direction), and the third direction Z is a vertical direction, which is perpendicular to the plane where the first substrate is located, as an example for illustration. These do not limit the present disclosure.
  • the bulk acoustic wave resonator includes a first substrate 10, a first electrode 11, a piezoelectric layer 12, a second electrode 13 and Temperature compensation layer 14.
  • the first substrate 10 has a first groove 101 .
  • the second electrode 13, the piezoelectric layer 12 and the first electrode 11 are arranged in sequence along the side away from the first substrate 10, that is, the first electrode 11, the piezoelectric layer 12 and the second electrode 13 are located in different directions in the second direction Y. layer.
  • the groove direction of the first groove 101 is toward the second electrode 13 , and the orthographic projection of the first groove 101 on the piezoelectric layer 12 covers the orthographic projection of the second electrode 13 on the piezoelectric layer 12 .
  • the second electrode 13 is not in contact with the first substrate 10 , that is, the length of the second electrode 13 in the first direction X is smaller than the length of the first groove 101 in the first direction X.
  • Orthographic projections of the first electrode 11 and the second electrode 13 on the piezoelectric layer 12 at least partially overlap. For example, if the dimensions and lengths of the first electrode 11 and the second electrode 13 in the first direction X are the same, the orthographic projections of the first electrode 11 and the second electrode 13 on the piezoelectric layer 12 may be set to completely overlap.
  • the temperature compensation layer 14 is disposed on the side of the first electrode 11 close to the first substrate 10 , and the temperature compensation layer 14 is in contact with the piezoelectric layer 12 . Specifically, the temperature compensation layer 14 may be disposed between the piezoelectric layer 12 and the first electrode 11, as shown in FIG. 1 . Of course, the temperature compensation layer 14 can also be disposed between the piezoelectric layer 12 and the second electrode 13, as shown in FIG. 2 .
  • the material of the first substrate 10 may include, but is not limited to, ceramics, glass materials, silicon, gallium arsenide, sapphire and other materials.
  • the material of the piezoelectric layer 12 may include single crystal piezoelectric material, such as single crystal aluminum nitride, and the piezoelectric layer 12 may be a single crystal aluminum nitride film.
  • single crystal aluminum nitride films have better crystal quality and high voltage electrical properties than polycrystalline aluminum nitride films.
  • BAW resonators composed of single crystal aluminum nitride films have better performance than polycrystalline aluminum nitride films.
  • the BAW resonator composed of polycrystalline aluminum nitride film has lower loss and higher Q value, where the Q value is the quality factor of the BAW resonator; the higher the Q value, the more stable the resonant frequency of the BAW resonator is. The better the performance.
  • f the thickness of single crystal piezoelectric materials is compared with that of polycrystalline piezoelectric materials. Large thickness.
  • f represents the resonant frequency
  • v the sound speed of the single crystal piezoelectric material
  • t represents the thickness of the piezoelectric layer 12 . It is known that the crystal quality of the piezoelectric layer 12 decreases as the thickness decreases. Therefore, at the same resonant frequency, the single crystal piezoelectric material provided by the embodiments of the present disclosure has better crystal quality than the polycrystalline piezoelectric material. and piezoelectric properties.
  • the thermal conductivity of the polycrystalline aluminum nitride film decreases as the thickness decreases, which limits the power processing capability of the BAW resonator.
  • the single crystal aluminum nitride film provided by embodiments of the present disclosure has a better thermal conductivity.
  • the first electrode 11 adopts the first electrode 11 with a ladder structure 110, as shown in the structural cross-sectional view of the bulk acoustic wave resonator in Figure 3a and Figure 3b, specifically,
  • the side of the first electrode 11 facing away from the first substrate 10 has at least one stepped structure 110;
  • the stepped structure 110 may include a protruding structure 111 and a second recess disposed on the side of the protruding structure 111 close to the central region CR of the first electrode 11.
  • the groove 112; the second groove 112 and the protruding structure 111 are all annular (see the structure shown in Figure 4a below).
  • Figure 3a takes the first electrode 11 as an example including a ladder structure 110.
  • the outer boundary of the protrusion structure 111 in the ladder structure 110 in the second direction Y is the outer boundary of the first electrode 11 in the second direction Y.
  • the second groove 112 is disposed on a side of the protruding structure 111 close to the central area of the first electrode 11, and the orthographic projection of the outline of the second groove 112 on the piezoelectric layer 12 is consistent with the outline of the protruding structure 111 on the piezoelectric layer. Orthographic projections on 12 do not overlap.
  • Figure 3a is a cross-sectional view along line EE' of the BAW resonator shown in Figure 4a.
  • the protruding structure 111 is an annular edge portion of the first electrode 11
  • the second groove 112 is formed inside the protruding structure 111 .
  • the first step 113 of the first electrode 11 It is a platform portion whose height in the second direction Y is between the convex surface of the protruding structure 111 and the bottom surface of the second groove 112).
  • a second step 114 (a platform portion whose height in the second direction Y is between the convex surface of the protruding structure 111 and the bottom surface of the second groove 112) is provided inside the second groove 112, which is connected with the second step 114.
  • the height of a step 113 in the second direction Y is the same. Therefore, the second groove 112 can be regarded as a concave structure formed inside the protruding structure 111 of the first electrode 11 and spaced apart from the protruding structure 111 . Both sides of the second groove 112 are first concave structures with the same height in the second direction Y. Platform 113 and second platform 114.
  • Figure 3b is a cross-sectional view along line EE' of the BAW resonator shown in Figure 4b.
  • the first electrode 11 may include a plurality of ladder structures 110, and the plurality of ladder structures 110 are nested. For example, among the plurality of annular structures of the plurality of ladder structures 110 of the first electrode 11 , one ladder structure 110 of every two adjacent ladder structures 110 is placed inside another ladder structure 110 , that is, every two adjacent ladder structures 110 One of the ladder structures 110 surrounds the other ladder structure 110 .
  • Figure 4b shows two nested ladder structures 110.
  • the first ladder structure 110-1 is disposed on the side of the second ladder structure 110-2 away from the central area of the first electrode 11, and the second groove 112-1 in the first ladder structure 110-1 is disposed on the second
  • the protruding structure 111-2 in the stepped structure 110-2 is away from the central area of the first electrode 11.
  • the outline of the second groove 112-1 in the first stepped structure 110-1 does not overlap with the orthographic projection of the outline of the protruding structure 111 in the second stepped structure 110-2 on the piezoelectric layer 12.
  • the embodiment of the present disclosure does not limit the separation distance between the second groove 112-1 and the protruding structure 111-2, and can be set according to actual conditions and experience.
  • the protruding structure 111-1 of the first stepped structure 110-1 is an annular edge part of the first electrode 11, and the second groove 112-1 of the first stepped structure 110-1 is formed Inside the protruding structure 111-1 of the first stepped structure 110-1.
  • the first step 113-1 of the first electrode 11 (which is a platform portion, the height of which in the second direction Y between the convex surface of the convex structure 111-1 of the first stepped structure 110-1 and the bottom surface of the second groove 112-1); provided inside the second groove 112-1 of the first stepped structure 110-1 is the second step 114-1 (which is the platform portion, the height of which in the second direction Y is between the convex surface of the protruding structure 111-1 and the bottom surface of the second groove 112-1), which is different from the first step 113-1 has the same height in the second direction Y.
  • the second groove 112-1 can be regarded as a concave structure formed inside the protruding structure 111-1 of the first electrode 11 and spaced apart from the protruding structure 111-1, and its two sides are in the second direction Y.
  • the first electrode 11 also includes a second ladder structure 110-2.
  • the protruding structure 111-2 of the second ladder structure 110-2 is an annular protruding part of the first electrode 11, which is different from the first ladder structure 110.
  • the second groove 112-1 of -1 is spaced apart from the second platform 114-1, and the second groove 112-2 of the second stepped structure 110-2 is formed on the protruding structure 111-2 of the second stepped structure 110-2.
  • the first step 113-2 of the first electrode 11 (which is a platform portion, the height of which is in the second direction Y between the convex surface of the convex structure 111-2 of the second ladder structure 110-2 and the bottom surface of the second groove 112-2); provided inside the second groove 112-2 of the second ladder structure 110-2 is the second step 114-2 (which is the platform portion, the height of which in the second direction Y is between the convex surface of the protruding structure 111-2 and the bottom surface of the second groove 112-2), which is different from the first step 113-2 has the same height in the second direction Y.
  • the second groove 112-2 can be regarded as a concave structure formed inside the protruding structure 111-2 of the first electrode 11 and spaced apart from the protruding structure 111-2, and its two sides are in the second direction Y. on the first platform 113-2 and the second platform 114-22 with the same height.
  • Figure 3b takes the first electrode 11 including two ladder structures 110 as an example, showing the first ladder structure 110-1 and the second ladder structure 110-2; the first ladder structure 110-1 includes a protrusion structure 111-1 and a The second groove 112-1; the stepped structure 111-2 and the second groove 112-2.
  • the nesting between two or more ladder structures provided by the embodiment of the present disclosure can refer to the nested arrangement of two ladder structures 110 shown in Figure 4b, and the repeated parts will not be described again.
  • the widths of the protruding structures 111 are respectively 2 ⁇ m, 4 ⁇ m, 6 ⁇ m, and 8 ⁇ m.
  • the frequency response simulation curve of the real part of the impedance where the horizontal axis is the frequency (unit: MHz), and the vertical axis represents the gain of the real part of the input impedance.
  • the width of the second groove 112 (the size along the first direction X shown in FIG. 3a and FIG. 3b ) is 2 ⁇ m, 3 ⁇ m, 4 ⁇ m, and 5 ⁇ m respectively.
  • the response simulation curve of the real part of the impedance changing with frequency where the horizontal axis is the frequency (unit: MHz), and the vertical axis represents the gain of the real part of the input impedance. It can be seen from the response simulation curves of the real part of the input impedance of different widths of the second groove 112 as a function of frequency that when the width of the second groove 112 is set to 4 ⁇ m, the spurious resonance peaks near the series and parallel resonant frequencies are smallest. Based on the above simulation results, the present disclosure can set the order
  • the width of the protruding structure 111 in the ladder structure 110 is between 5.5 ⁇ m and 6.5 ⁇ m, for example, 6 ⁇ m.
  • the present disclosure may set the width of the second groove 112 in the stepped structure 110 to be between 3.5 ⁇ m and 4.5 ⁇ m, for example, 4 ⁇ m.
  • This ladder structure 110 can effectively suppress the spurious vibration of the BAW resonator and improve the Q value of the BAW resonator.
  • the width w1 of the protruding structure 111 can be between 5.5 ⁇ m and 6.5 ⁇ m, and the thickness h1 of the protruding structure 111 (along the lines shown in Figures 3a and 3b
  • the size in the second direction Y is the size between the convex surface of the protruding structure 111 (the surface away from the first substrate direction) and the platform portion 113/114 in the direction perpendicular to the first substrate) and the first electrode 11
  • the thickness ratio may be between 9/20 and 11/20.
  • the thickness h1 of the protruding structure 111 may be half of the thickness of the first electrode 11.
  • the thickness of the first electrode 11 may be between 0.3 ⁇ m and 0.5 ⁇ m.
  • the thickness of the protruding structure 111 may be between 0.15 ⁇ m and 0.25 ⁇ m.
  • the width w2 of the second groove 112 may be between 3.5 ⁇ m and 4.5 ⁇ m.
  • the thickness h2 of the second groove 112 (the size along the second direction Y shown in FIGS. 3a and 3b ) is the second groove.
  • the ratio between the bottom surface of 112 and the platform portion 113/114 in the direction perpendicular to the first substrate) and the thickness of the first electrode 11 can be 1/5 to 3/10, for example, the thickness of the second groove 112 h2 may be one quarter of the thickness of the first electrode 11.
  • the thickness of the second groove 112 may be between 0.075 ⁇ m and 0.175 ⁇ m.
  • the material of the first electrode 11 and the second electrode 13 may include, but are not limited to: platinum, aluminum, molybdenum and other materials.
  • the orthographic projections of the outline of the second groove 112 and the outline of the protruding structure 111 on the first substrate 10 are both regular polygons.
  • regular polygons may include, but are not limited to: regular quadrilaterals, regular pentagons, regular hexagons, etc.
  • the central region CR at least includes the center C of a regular polygon, such as the center of a regular quadrilateral (Fig. 4c), a regular pentagon (Fig. 4b), and a regular hexagon (Fig. 4d).
  • the central area CR is a circle with center C as the center and radius r, as shown in Figure 4a As shown in Figure 4d.
  • Figure 3a is a cross-sectional view of the BAW resonator shown in Figure 4a along line EE';
  • Figure 3b is a cross-sectional view of the BAW resonator shown in Figures 4b to 4d along line EE', used to illustrate the first electrode 11 away from the surface morphology of the first substrate 10 .
  • orthographic projections of the contours of the second groove 112 and the protruding structure 111 on the first substrate 10 may be irregular polygons, but the irregular polygons do not contain acute angles.
  • the material of the piezoelectric layer 12, the material of the first electrode 11 and the material of the second electrode 13 in the BAW resonator have negative temperature coefficients.
  • the embodiment of the present disclosure provides a temperature compensation layer 14.
  • the temperature compensation layer 14 is made of a material with a positive temperature coefficient and can compensate for a negative temperature coefficient. The frequency shift of the resonator caused by the temperature change of the material.
  • positive temperature coefficient materials may include, but are not limited to, silicon dioxide.
  • the thickness of the temperature compensation layer 14 can meet at least one of the following conditions:
  • the ratio of the thickness of the temperature compensation layer 14 to the thickness of the second electrode 13 is between 19/20 and 21/20;
  • the ratio of the thickness of the temperature compensation layer 14 to the thickness of the first electrode 11 is between 9/20 and 11/20;
  • the ratio of the thickness of the temperature compensation layer 14 to the thickness of the piezoelectric layer 12 is between 1/20 and 3/20.
  • the thickness of the temperature compensation layer 14 may be the same as the thickness of the second electrode 13; for example, the thickness of the temperature compensation layer 14 and the thickness of the second electrode 13 are both between 0.15 ⁇ m and 0.25 ⁇ m.
  • the ratio of the thickness of the temperature compensation layer 14 to the thickness of the first electrode 11 can be 1/2; if the thickness of the first electrode 11 is between 0.3 ⁇ m and 0.5 ⁇ m, the thickness of the temperature compensation layer 14 can be set between 0.15 ⁇ m and 0.25 ⁇ m. between ⁇ m.
  • the ratio of the thickness of the temperature compensation layer 14 to the thickness of the piezoelectric layer 12 may be 1/10; for example, if the thickness of the piezoelectric layer 12 is set between 1.5 ⁇ m and 2.5 ⁇ m, the thickness of the temperature compensation layer 14 may be set to Between 0.15 ⁇ m ⁇ 0.25 ⁇ m.
  • the orthographic projection of the temperature compensation layer 14 on the piezoelectric layer 12 at least partially overlaps with the orthographic projection of the first electrode 11 and the second electrode 13 on the piezoelectric layer 12 .
  • the dimensions and lengths of the first electrode 11 and the second electrode 13 in the first direction It completely overlaps with the orthographic projection of the temperature compensation layer 14 on the piezoelectric layer 12 .
  • the piezoelectric layer 12 may include an epitaxial growth layer 121 .
  • the piezoelectric layer 12 may further include a seed layer 122.
  • the piezoelectric layer 12 includes an epitaxial growth layer 121 and a seed layer 122 sequentially arranged along the side of the second electrode 13 away from the first substrate 10 .
  • the BAW resonator further includes a passivation layer 15 , and the passivation layer 15 is disposed on the side of the first electrode 11 away from the first substrate 10 , as shown in FIG. 9 f .
  • the material of the passivation layer 15 may be the same as the material of the piezoelectric layer 12 , for example, the material of the passivation layer 15 is single crystal aluminum nitride.
  • the passivation layer 15 can protect the structure of the BAW resonator and prevent the internal structure of the BAW resonator from being affected by external conditions such as moisture, corrosion, contaminants, and debris.
  • embodiments of the disclosure also provide a method for preparing a bulk acoustic wave resonator.
  • the principle of the problem solved by the bulk acoustic wave resonator in the embodiment of the disclosure is the same as that of the embodiment of the bulk acoustic wave resonator mentioned above.
  • the principles of the problems solved by the disclosed bulk acoustic wave resonators are similar. Therefore, for the specific structure of the bulk acoustic wave resonator in the preparation method of the bulk acoustic wave resonator, please refer to the specific structure of the BAW resonator in the above embodiment of the bulk acoustic wave resonator. The repetitive parts will not be repeated.
  • the piezoelectric layer 12 is formed on the second substrate 16.
  • the thickness of the second substrate 16 may be between 10 ⁇ m and 600 ⁇ m.
  • a metal organic chemical vapor deposition process may be used to form a piezoelectric layer 12 on the second substrate 16 .
  • the thickness of the piezoelectric layer 12 may be between 1.5 ⁇ m and 2.5 ⁇ m.
  • the step S1 of forming the piezoelectric layer 12 specifically includes S1-1 and S1-2:
  • the thickness of the seed layer 122 may be between 0.5 ⁇ m and 1 ⁇ m;
  • S1-2 Use a metal organic chemical vapor deposition process to form a second material layer on the side of the seed layer 122 facing away from the second substrate 16.
  • the second material layer grows epitaxially under the action of the first material layer to form an epitaxial layer.
  • the layer 121 is grown to form the piezoelectric layer 12 which is stacked by the seed layer 122 and the epitaxial growth layer 121 .
  • the first material layer serving as the seed layer 122 can promote the second material layer to have a good crystal orientation during epitaxial growth.
  • the material of the formed first material layer and the material of the second material layer may be single crystal aluminum nitride.
  • the thickness of the formed epitaxial growth layer 121 may be between 1 ⁇ m and 1.5 ⁇ m.
  • the second electrode 13 is formed on the side of the piezoelectric layer 12 facing away from the second substrate 16.
  • the thickness of the second electrode 13 may be between 0.15 ⁇ m and 0.25 ⁇ m.
  • a magnetron sputtering process is used to form the second electrode 13 on the side of the piezoelectric layer 12 facing away from the second substrate 16 .
  • the first substrate 10 has a first groove 101.
  • the groove direction of the groove 101 is toward the second electrode 13 , and the orthographic projection of the first groove 101 on the piezoelectric layer 12 covers the orthographic projection of the second electrode 13 on the piezoelectric layer 12 .
  • the first substrate 10 has a first groove 101. After the second substrate 16 on which the piezoelectric layer 12 and the second electrode 13 are formed is bonded to the first substrate 10, an air gap is formed. The air gap is used for Confines sound waves within the BAW resonator.
  • the thickness of the first substrate 10 may be between 400 ⁇ m and 600 ⁇ m.
  • the thickness of the first groove 101 may be between 1/3 and 1/2 of the thickness of the first substrate 10 .
  • the second substrate 16 is removed.
  • the specific preparation process is as follows: first, flip the BAW resonator structure shown in Figure 9c; then, use a mechanical grinding process to thin the second substrate 16 to 1/3 to 1/2 of the second substrate 16, and then the remaining second substrate 16 is removed through a patterning process.
  • forming the first electrode 11 may specifically include the following steps S4-1 to S4-2:
  • the thickness of the material layer of the first electrode 11 may be between 0.3 ⁇ m and 0.5 ⁇ m.
  • first electrode 11 with at least one ladder structure 110 through a patterning process, where the ladder structure 110 includes a protruding structure 111 and a second groove 112; on the side of the first electrode 11 facing away from the first substrate 10 A protruding structure 111 is formed; a second groove 112 is formed on the side of the protruding structure 111 close to the central area of the first electrode 11; both the second groove 112 and the protruding structure 111 are annular.
  • the thickness of the protruding structure 111 may be half of the thickness of the first electrode 11 ; the thickness of the second groove 112 may be one-quarter of the thickness of the first electrode 11 .
  • photoresist coating, exposure, development, etching, and photoresist stripping are sequentially performed on the material layer of the first electrode 11 to form the first electrode 11 with at least one ladder structure 110 .
  • the width of the protruding structure 111 may be between 5.5 ⁇ m and 6.5 ⁇ m, and the thickness may be between 0.15 ⁇ m and 0.25 ⁇ m; and/or the width of the second groove 112 may be between 3.5 ⁇ m and 4.5 ⁇ m, and the thickness may be between 3.5 ⁇ m and 4.5 ⁇ m. Between 0.075 ⁇ m ⁇ 0.175 ⁇ m.
  • the formed first electrode 11 may include multiple ladder-like structures, and the multiple ladder-like structures are nested.
  • the specific nested structures can be seen in Figures 4b to 4d, and Figures 4b to 4d. The corresponding explanation content will not be repeated again.
  • a temperature compensation layer 14 may be formed on a side of the first electrode 11 close to the first substrate 10; the temperature compensation layer 14 is in contact with the piezoelectric layer 12.
  • the temperature compensation layer 14 can have a variety of different preparation methods.
  • the temperature compensation layer 14 can also be formed between the piezoelectric layer 12 and the first electrode 11. As shown in Figure 1.
  • a temperature compensation layer 14 may also be formed between the piezoelectric layer 12 and the second electrode 13, as shown in FIG. 2 .
  • the thickness of the temperature compensation layer 14 may be between 0.15 ⁇ m and 0.25 ⁇ m.
  • a passivation layer 15 is formed on the side of the first electrode 11 away from the first substrate 10.
  • embodiments of the present disclosure also provide an electronic device, which can It includes a bulk acoustic wave resonator disclosed in the above embodiments of the present disclosure, wherein the principle of the problem solved by the bulk acoustic wave resonator in electronic equipment is the same as the bulk acoustic wave resonator disclosed in the above embodiments of the present disclosure.
  • the principles of the problems solved by the acoustic wave resonator are similar. Therefore, for the specific structure of the bulk acoustic wave resonator in the electronic device according to the embodiment of the present disclosure, please refer to the specific structure of the BAW resonator in the above embodiment of the bulk acoustic wave resonator. The repeated details will not be repeated. .

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  • Physics & Mathematics (AREA)
  • Acoustics & Sound (AREA)
  • Engineering & Computer Science (AREA)
  • Manufacturing & Machinery (AREA)
  • Piezo-Electric Or Mechanical Vibrators, Or Delay Or Filter Circuits (AREA)
  • Surface Acoustic Wave Elements And Circuit Networks Thereof (AREA)

Abstract

La présente divulgation appartient au domaine technique des résonateurs à ondes acoustiques de volume. L'invention concerne un résonateur à ondes acoustiques de volume, un procédé de préparation d'un résonateur à ondes acoustiques de volume, et un dispositif électronique. Le résonateur à ondes acoustiques de volume comprend un premier substrat, une première électrode, une couche piézoélectrique, une deuxième électrode et une couche de compensation de température, le premier substrat étant pourvu d'une première rainure ; la deuxième électrode, la couche piézoélectrique et la première électrode sont agencées séquentiellement le long d'un côté qui est opposé au premier substrat ; une ouverture de la première rainure fait face à la deuxième électrode, et une projection orthographique de la première rainure sur la couche piézoélectrique recouvre une projection orthographique de la deuxième électrode sur la couche piézoélectrique ; des projections orthographiques de la première électrode et de la deuxième électrode sur la couche piézoélectrique se chevauchent au moins partiellement ; la couche de compensation de température est disposée sur le côté de la première électrode proche du premier substrat, et est en contact avec la couche piézoélectrique ; et le côté de la première électrode qui est opposé au premier substrat est pourvu d'au moins une structure étagée, la structure étagée comprend une structure en saillie et une deuxième rainure, qui est disposée sur le côté de la structure en saillie à proximité de la zone centrale de la première électrode, et la deuxième rainure et la structure en saillie sont toutes deux annulaires.
PCT/CN2023/088850 2022-04-20 2023-04-18 Résonateur à ondes acoustiques de volume, procédé de préparation de résonateur à ondes acoustiques de volume et dispositif électronique WO2023202548A1 (fr)

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CN202210417755.6A CN116961611A (zh) 2022-04-20 2022-04-20 一种体声波谐振器、体声波谐振器的制备方法和电子设备
CN202210417755.6 2022-04-20

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US9401691B2 (en) * 2014-04-30 2016-07-26 Avago Technologies General Ip (Singapore) Pte. Ltd. Acoustic resonator device with air-ring and temperature compensating layer
US20170288121A1 (en) * 2016-03-31 2017-10-05 Avago Technologies General Ip (Singapore) Pte. Ltd Acoustic resonator including composite polarity piezoelectric layer having opposite polarities
CN109889179A (zh) * 2018-12-26 2019-06-14 天津大学 谐振器和梯形滤波器
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CN114362716A (zh) * 2021-12-23 2022-04-15 苏州汉天下电子有限公司 一种谐振器、滤波器、通信设备及其制造方法

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