WO2021143409A1 - 一种复合基板及其制造方法、表声波谐振器及其制造方法 - Google Patents

一种复合基板及其制造方法、表声波谐振器及其制造方法 Download PDF

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Publication number
WO2021143409A1
WO2021143409A1 PCT/CN2020/135659 CN2020135659W WO2021143409A1 WO 2021143409 A1 WO2021143409 A1 WO 2021143409A1 CN 2020135659 W CN2020135659 W CN 2020135659W WO 2021143409 A1 WO2021143409 A1 WO 2021143409A1
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Prior art keywords
polycrystalline
composite substrate
piezoelectric
manufacturing
layer
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PCT/CN2020/135659
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English (en)
French (fr)
Inventor
黄河
罗海龙
李伟
齐飞
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中芯集成电路（宁波）有限公司
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Priority to JP2022543079A priority Critical patent/JP7443535B2/ja
Publication of WO2021143409A1 publication Critical patent/WO2021143409A1/zh
Priority to US17/867,629 priority patent/US20220352870A1/en

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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
    • 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
    • H03H9/02535—Details of surface acoustic wave devices
    • H03H9/02543—Characteristics of substrate, e.g. cutting angles
    • H03H9/02574—Characteristics of substrate, e.g. cutting angles of combined substrates, multilayered substrates, piezoelectrical layers on not-piezoelectrical substrate
    • 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
    • H03H3/08—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 resonators or networks using surface acoustic waves
    • 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
    • H03H9/02535—Details of surface acoustic wave devices
    • H03H9/02543—Characteristics of substrate, e.g. cutting angles
    • H03H9/02559—Characteristics of substrate, e.g. cutting angles of lithium niobate or lithium-tantalate substrates
    • 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
    • H03H9/02535—Details of surface acoustic wave devices
    • H03H9/02637—Details concerning reflective or coupling arrays
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
    • H03H9/00—Networks comprising electromechanical or electro-acoustic devices; Electromechanical resonators
    • H03H9/25—Constructional features of resonators using surface acoustic waves
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
    • H03H9/00—Networks comprising electromechanical or electro-acoustic devices; Electromechanical resonators
    • H03H9/46—Filters
    • H03H9/64—Filters using surface acoustic waves
    • H—ELECTRICITY
    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10N—ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10N30/00—Piezoelectric or electrostrictive devices

Definitions

  • the invention relates to the field of semiconductor device manufacturing, in particular to a composite substrate and a manufacturing method thereof, and a surface acoustic wave resonator and a manufacturing method thereof.
  • high-power filters in wireless base stations and other equipment are mainly cavity filters, whose power can reach hundreds of watts, but the size of such filters is too large.
  • Some equipment uses dielectric filters, with an average power of more than 5 watts, and the size of this filter is also very large. Due to its large size, the cavity filter cannot be integrated into the RF front-end chip.
  • high-power filters in wireless base stations and other equipment are mainly cavity filters, whose power can reach hundreds of watts, but the size of such filters is too large.
  • Some equipment uses dielectric filters, with an average power of more than 5 watts, and the size of this filter is also very large. Due to its large size, the cavity filter cannot be integrated into the RF front-end chip.
  • One of the main filters in thin film filters based on semiconductor micromachining technology is a surface acoustic wave resonator (SAW).
  • SAW surface acoustic wave resonator
  • the piezoelectric substrate used in the surface acoustic wave resonator is usually formed by bonding a silicon substrate and a single crystal piezoelectric wafer to thinner.
  • the single-crystal piezoelectric wafer material is very fragile and easily cracked during the semiconductor process.
  • the process menu requires special design, which reduces the production efficiency.
  • the current largest wafer size still stays at 6 inches, and even many filter manufacturers use 4-inch technology in their process lines, and the number of filter chips produced on a single wafer is relatively small.
  • the cost of a single wafer is relatively high, so that the cost of the surface acoustic wave filter cannot be further reduced.
  • the invention discloses a composite substrate and a manufacturing method thereof, and a surface acoustic wave resonator and a manufacturing method thereof, so as to solve the problems that the piezoelectric induction film chip is easy to be broken during the manufacturing process, and has high cost and low efficiency.
  • the present invention provides a method for manufacturing a composite substrate, including:
  • the piezoelectric induction film is subjected to recrystallization annealing treatment to make the piezoelectric induction film reach a polycrystalline state, wherein the crystallization annealing includes a heating process and a cooling process, and the heating process includes performing a heating process on the piezoelectric induction film.
  • the temperature rise causes the piezoelectric induction film to reach a molten state.
  • the present invention also provides a composite substrate, including:
  • the piezoelectric induction film for generating acoustic resonance is located above the polycrystalline material layer, and the piezoelectric induction film is in a polycrystalline state.
  • the present invention also provides a surface acoustic wave resonator, including the above-mentioned composite substrate.
  • the present invention also provides a method for manufacturing a surface acoustic wave resonator, including: the above-mentioned composite substrate, and the manufacturing method further includes:
  • a first interdigital transducer and a second interdigital transducer are formed on the piezoelectric induction film.
  • single crystal is generally used as the piezoelectric film of the surface acoustic wave resonator, and polycrystalline is not used as the piezoelectric film of the surface acoustic wave resonator.
  • the main reason is that the industry generally believes that the polycrystalline piezoelectric film is not good for the sound wave. Propagation affects the performance of the resonator.
  • the inventor found that although the polycrystalline piezoelectric film is composed of single crystal particles, the single crystal particles are not arranged neatly and do not form a consistent crystal orientation, but the crystal orientation of the piezoelectric film has a very small effect on the piezoelectric performance, so Compared with the single crystal film, the performance of the polycrystalline piezoelectric film formed in this solution is consistent.
  • a polycrystalline material layer is formed on the substrate, and the polycrystalline material layer has a better crystal orientation, so that the piezoelectric induction film deposited thereon can obtain a better crystal orientation, polycrystalline material layer after an annealing process.
  • Crystalline piezoelectric sensing film Compared with the traditional method of bonding piezoelectric wafers on the substrate, this process of forming a polycrystalline piezoelectric sensing film on a substrate avoids the problems of piezoelectric crystal fragmentation, low production efficiency, and high cost.
  • the polycrystalline piezoelectric film is formed after deposition and recrystallization.
  • the growth process is simple and the cost is low; moreover, because the polycrystalline piezoelectric film has better structural strength than the single-crystal piezoelectric film, It is not easy to break; in addition, deposition and annealing technology has no limitation on wafer size, and can be applied to 6-inch, 8-inch and other production processes. Moreover, since the stress direction of the polycrystalline particles is not concentrated, the stress in a single direction will not be large, and compared with the single crystal, the risk of cracking of the piezoelectric film is greatly reduced.
  • the surface roughness index of the polycrystalline piezoelectric film is less than 10 nm, and the flatness is high.
  • the acoustic energy scattering can be minimized.
  • the polycrystalline material itself or the acoustic wave reflection layer is formed between the substrate and the polycrystalline material.
  • the longitudinal sound wave is transmitted to the acoustic wave reflection layer, it is reflected back into the piezoelectric sensing film, which reduces the energy loss of the sound wave and improves the resonator.
  • the Q value is the Q value.
  • the surface flatness of the piezoelectric induction film is improved, and the piezoelectric characteristics of the piezoelectric induction film are improved.
  • Fig. 1 shows a flow chart of a method for manufacturing a composite substrate according to an embodiment of the present invention.
  • FIGS. 2 to 4 show schematic diagrams of the structure of a composite substrate according to an embodiment of the present invention.
  • Fig. 5 shows a schematic structural diagram of a surface acoustic wave resonator according to an embodiment of the present invention.
  • Fig. 6 shows a schematic structural diagram of a surface acoustic wave resonator according to another embodiment of the present invention.
  • first element, component, region, layer or section discussed below may be represented as a second element, component, region, layer or section.
  • Spatial relationship terms such as “under”, “below”, “below”, “below”, “above”, “above”, etc., in It can be used here for the convenience of description to describe the relationship between one element or feature shown in the figure and other elements or features. It should be understood that in addition to the orientations shown in the figures, the spatial relationship terms are intended to include different orientations of devices in use and operation. For example, if the device in the figure is turned over, then elements or features described as “under” or “below” or “under” other elements will be oriented “on” the other elements or features. Therefore, the exemplary terms “below” and “below” can include both an orientation of above and below. The device can be otherwise oriented (rotated by 90 degrees or other orientation) and the spatial descriptors used here are interpreted accordingly.
  • the method herein includes a series of steps, and the order of these steps presented herein is not necessarily the only order in which these steps can be performed, and some steps may be omitted and/or some other steps not described herein may be added to this method. If the components in a certain drawing are the same as those in other drawings, although these components can be easily identified in all the drawings, in order to make the description of the drawings more clear, this specification will not describe all the same components. The reference numbers are shown in each figure.
  • FIG. 1 shows a flowchart of a method for manufacturing a composite substrate according to an embodiment of the present invention.
  • the method for manufacturing a composite substrate includes:
  • S02 Deposit a liner layer on the first substrate, the liner layer at least including a polycrystalline material layer;
  • S04 Perform recrystallization annealing treatment on the piezoelectric induction film to make the piezoelectric induction film reach a polycrystalline state, wherein the crystallization annealing includes a heating process and a cooling process, and the heating process includes sensing the piezoelectric The temperature of the film is raised so that the piezoelectric induction film reaches a molten state.
  • Figures 2 to 4 show schematic structural diagrams at different stages of a composite substrate manufacturing method according to an embodiment of the present invention.
  • the composite substrate manufacturing method includes:
  • step S01 provide a first substrate 10
  • the material of the first substrate 10 is selected to be suitable for the semiconductor process, and may be at least one of the following materials: silicon (Si), germanium (Ge), silicon germanium (SiGe), silicon carbon (SiC), carbon Silicon germanium (SiGeC), indium arsenide (InAs), gallium arsenide (GaAs), indium phosphide (InP) or other III/V compound semiconductors, or silicon-on-dielectric (SOI), silicon-on-dielectric ( SSOI), stacked silicon germanium on dielectric body (S-SiGeOI), silicon germanium on dielectric body (SiGeOI), germanium on dielectric body (GeOI), or double-sided polished silicon wafer (Double Side Polished Wafers (DSP), ceramic substrates such as alumina, quartz or glass substrates, etc. can also be used.
  • the material of the first substrate 10 is P-type silicon with a resistance greater than 10 KOhm.cm.
  • the reason for choosing a substrate material with a high resistance value is: when there is alternating current above the first substrate, the alternating current generates electromagnetic waves, and the electromagnetic wave radiation loses part of the electric energy. Under low frequency conditions, the radiation loss is small, but under high frequency conditions, radiation The loss increases, and the use of high-resistance substrate materials can reduce electromagnetic wave radiation and reduce power loss.
  • step S02 is performed: a liner layer 20 is deposited on the first substrate 10, the liner layer 20 includes at least a polycrystalline material layer.
  • the polycrystalline material layer has a good crystal orientation.
  • the piezoelectric induction film is crystallized according to the crystal orientation of the crystalline material layer.
  • the material of the polycrystalline material layer includes polycrystalline alumina, polycrystalline silicon dioxide or polycrystalline silicon carbide.
  • the liner layer 20 is polycrystalline aluminum oxide.
  • the polycrystalline material layer has a better crystal orientation, so that the piezoelectric induction film deposited thereon can obtain a piezoelectric induction film with a better crystal orientation and a polycrystalline state after passing through an annealing process. Compared with the traditional method of bonding piezoelectric wafers on the substrate, this process of forming a polycrystalline piezoelectric sensing film on a substrate avoids the problems of piezoelectric crystal fragmentation, low production efficiency, and high cost.
  • the method for depositing the liner layer 20 (depositing a polycrystalline material layer in this embodiment) on the first substrate 10 includes: depositing on the first substrate 10 by physical vapor deposition or chemical vapor deposition to form a thickness of 2000 angstroms to 10000 angstroms.
  • a layer of polycrystalline material The thickness of the polycrystalline material layer should not be too thin, otherwise the quality of the polycrystalline layer itself is not good, which will affect the quality of the piezoelectric sensing film formed on it in the later process; moreover, if the polycrystalline material layer is used as an acoustic wave reflection layer, Need to reach a certain thickness. The polycrystalline layer does not need to be too thick, otherwise the production efficiency will be affected.
  • the backing layer 20 further includes an acoustic wave reflection layer formed between the polycrystalline material layer and the first substrate 10.
  • the acoustic wave reflection layer and the piezoelectric induction film formed in the later process have a large impedance mismatch.
  • the acoustic wave reflection layer reflects the sound wave back into the piezoelectric induction film, reducing the energy loss of the sound wave.
  • the material of the acoustic wave reflection layer includes: aluminum oxide, silicon dioxide, silicon nitride or silicon carbide.
  • the method for depositing the liner layer 20 (including the acoustic wave reflection layer and the polycrystalline material layer) on the first substrate 10 includes: depositing on the first substrate 10 by physical vapor deposition or chemical vapor deposition to form a thickness of 2000 angstroms to 10000 angstroms. Angstrom of sound wave reflection layer. On the acoustic wave reflection layer, a polycrystalline material layer with a thickness of 2000 angstroms to 10000 angstroms is formed by physical vapor deposition or chemical vapor deposition. The method of forming the polycrystalline material layer belongs to the prior art and will not be repeated here.
  • the acoustic wave reflection layer and the polycrystalline material layer may be the same layer.
  • the material of the liner layer may be polycrystalline alumina, polycrystalline silicon dioxide, or polycrystalline silicon carbide.
  • step S03 a piezoelectric induction film 30 for generating acoustic resonance is deposited on the polycrystalline material layer by a physical or chemical deposition method.
  • the piezoelectric sensing film material is deposited on the polycrystalline material layer by a physical vapor deposition method.
  • the thickness of the piezoelectric sensing film material is usually between 0.01 and 10 microns, and the thickness in this embodiment is 0.4um to 5um.
  • the choice of the thickness of the piezoelectric sensing film material mainly considers two aspects. On the one hand, it can realize the performance of the resonator, and on the other hand, the stability of the process can be controlled.
  • Physical vapor deposition methods include vacuum evaporation, sputtering, and ion plating.
  • the purity of the target material of the piezoelectric material used in physical vapor deposition is greater than 99.99% to ensure that the deposited piezoelectric induction film has fewer impurities or defects, and to ensure that the yield of the resonator and filter reaches the target value that can be mass-produced.
  • the formed piezoelectric sensing film 30 is in a microcrystalline or amorphous state.
  • the piezoelectric induction film 30 deposited in this embodiment is used for the surface acoustic wave resonator.
  • the material of the piezoelectric sensing film 30 may be one or a combination of lithium niobate, lithium tantalate, lithium tetraborate, bismuth germanate, lanthanum gallium silicate, aluminum orthophosphate, or potassium niobate.
  • the selected sputtering target is made by sintering lithium acetate and tantalum pentoxide as raw materials, and the gas used for the sputtering ion source is argon.
  • step S04 is performed: performing recrystallization annealing treatment on the piezoelectric induction film 30 to make the piezoelectric induction film 30 reach a polycrystalline state, wherein the crystallization annealing includes a heating process and a cooling process.
  • the heating process includes heating the piezoelectric induction film 30 to make the piezoelectric induction film 30 reach a molten state.
  • the piezoelectric induction film 20 is subjected to recrystallization annealing treatment at a temperature at which the piezoelectric induction film 30 reaches a molten state.
  • recrystallization annealing treatment There are two methods of recrystallization annealing treatment. One is to uniformly heat the entire first substrate, liner layer, and piezoelectric induction film.
  • a furnace tube is used to heat the piezoelectric induction film 30, the liner layer 20, The entire first substrate 10 is heated to make the piezoelectric induction film 30 reach a molten state, and the piezoelectric induction film 30 is recrystallized.
  • the other is to locally heat the piezoelectric induction film 30, such as scanning and heating the piezoelectric induction film 30 with a laser to make the piezoelectric induction film 30 reach a molten state and recrystallize the piezoelectric induction film 30.
  • the first recrystallization annealing method specifically includes: putting the first substrate 10 on which the piezoelectric induction film 30 is deposited into a high temperature furnace, such as a horizontal furnace, a vertical furnace, or rapid thermal processing (RTP). Heat at a temperature of 1100 to 1200 degrees for 2 to 5 minutes.
  • a high temperature furnace such as a horizontal furnace, a vertical furnace, or rapid thermal processing (RTP).
  • RTP rapid thermal processing
  • the second recrystallization annealing method specifically includes: in a vacuum, nitrogen or oxygen atmosphere, a pulsed laser of 0.8-15 joules per square centimeter, a laser frequency of 1-10KHz, acting on the piezoelectric induction film for 5 seconds to 20 seconds. Seconds (different piezoelectric induction film has different action time), and the temperature of the piezoelectric induction film is heated to 1000-1400 in the form of scanning to reach the molten state and recrystallize.
  • the material of the piezoelectric induction film 30 is lithium niobate or lithium tantalate
  • the recrystallization annealing treatment of the piezoelectric induction film 30 by furnace tube annealing includes: Layer 20 and piezoelectric induction film 30 are uniformly heated to 1100 degrees to 1300 degrees, heating time is 5 to 30 seconds, and then cooled to room temperature. The cooling rate is lower than 5 degrees Celsius per second to prevent piezoelectric induction film 30 from peeling Or chipped.
  • the method further includes: polishing the upper surface of the piezoelectric sensing film 30 by a mechanical or mechanochemical polishing process, such as by chemical mechanical polishing (CMP).
  • CMP chemical mechanical polishing
  • the surface roughness index of the piezoelectric sensing film 30 after polishing is less than 10 nanometers.
  • the method further includes: trimming the upper surface of the piezoelectric sensing film 30 through an ion beam trimming process, and the surface thickness of the piezoelectric sensing film 30 after trimming is The uniformity is less than 2%.
  • the trimming precision of the ion beam can reach the nanometer level, and the local and overall surface height of the piezoelectric sensing film 30 can be trimmed.
  • the height of the piezoelectric sensing film on the whole substrate after trimming is consistent, which improves the performance consistency of adjacent devices and improves the yield of the resonator.
  • the ion beam trimming process adopts the following parameters: the ion beam current is 25 mA to 200 mA, and the scanning time is 30 seconds to 10 minutes.
  • the surface flatness of the piezoelectric induction film is improved, and the piezoelectric characteristics of the piezoelectric induction film are improved.
  • FIG. 4 shows a schematic structural diagram of a composite substrate according to an embodiment of the present invention. Please refer to Fig. 4, the composite substrate includes:
  • the liner layer 20 is located on the upper surface of the first substrate 10, and the liner layer 20 at least includes a polycrystalline material layer;
  • the piezoelectric sensing film 30 for generating acoustic resonance is located above the polycrystalline material layer, and the piezoelectric sensing film is in a 30-polycrystalline state.
  • the material of the first substrate 10 is P-type silicon with a resistance greater than 10 KOhm.cm.
  • the reason for choosing a substrate material with a high resistance value is that when there is alternating current above the first substrate, the alternating current generates electromagnetic waves, and the electromagnetic wave radiation loses part of the electric energy. Under low frequency conditions, the radiation loss is small, but under high frequency conditions, radiation The loss increases, and the use of high-resistance substrate materials can reduce electromagnetic wave radiation and reduce power loss.
  • the liner layer 20 has a single-layer film structure, that is, a polycrystalline material layer, and the polycrystalline material layer includes polycrystalline aluminum oxide, polycrystalline silicon dioxide, or polycrystalline silicon carbide.
  • the backing layer further includes an acoustic wave reflection layer, and the acoustic wave reflection layer is disposed between the first substrate and the polycrystalline material layer.
  • the material of the acoustic wave reflection layer includes aluminum oxide, silicon dioxide, silicon nitride or silicon carbide.
  • the acoustic wave reflection layer and the polycrystalline material layer may be the same layer.
  • the material of the liner layer includes polycrystalline alumina, polycrystalline silicon dioxide, or polycrystalline silicon carbide.
  • the function of the sound wave reflection layer When the longitudinal sound wave is transmitted to the sound wave reflection layer, it is reflected back into the piezoelectric induction film, which reduces the energy loss of the sound wave and improves the Q value of the resonator.
  • the first substrate further includes an acoustic reflection structure
  • the acoustic reflection structure includes a cavity or a Bragg reflection layer.
  • the acoustic reflection structure is used to introduce the piezoelectric sheet body into the longitudinal sound wave reflection of the first substrate or into the piezoelectric sheet, so as to further reduce the energy loss of the sound wave.
  • FIG. 5 shows a structural diagram of a surface acoustic wave resonator according to an embodiment of the present invention. Referring to FIG. 5, the method includes:
  • a first interdigital transducer 41 and a second interdigital transducer 42 are formed on the piezoelectric induction film 30.
  • a first conductive film is formed on the surface of the piezoelectric induction film 30.
  • the first conductive film can be formed on the surface of the piezoelectric induction film by physical vapor deposition such as magnetron sputtering, vapor deposition, or chemical vapor deposition.
  • the material of the first conductive film can be any suitable conductive material, for example: molybdenum (Mo), aluminum (Al), copper (Cu), tungsten (W), tantalum (Ta), platinum (Pt), ruthenium (Ru) ), rhodium (Rh), iridium (Ir), chromium (Cr), titanium (Ti), gold (Au), osmium (Os), rhenium (Re), palladium (Pd), platinum, nickel and other metals Made of or made of the above alloys.
  • the first conductive film is patterned to form a first interdigital transducer 41 and a second interdigital transducer 42.
  • the manufactured resonator is a surface acoustic wave resonator (SAW), and the method of patterning the first conductive film includes dry etching and wet etching.
  • the first interdigital transducer 41 includes a plurality of first conductive fingers that are parallel to each other, and the first interdigital transducer 41 includes a plurality of second conductive fingers that are parallel to each other.
  • the first interdigital transducer 41 and the second interdigital transducer 42 are parallel to each other, including two situations: one is that the first conductive fingers and the second conductive fingers are arranged in parallel and staggered with each other, and the other is the first conductive fingers.
  • the interdigital transducer 41 and the second interdigital transducer 42 are arranged separately, and the first conductive fingers and the second conductive fingers are parallel to each other, but not interlaced with each other. This embodiment is arranged according to the first situation.
  • the first interdigital transducer 41 and the second interdigital transducer 42 may not be parallel, as long as they do not intersect.
  • the composite substrate is formed with an acoustic reflection structure, and the first and second interdigital transducers are formed above the area enclosed by the acoustic reflection structure.
  • the acoustic reflection structure is a first cavity 51, and forming the first cavity 51 includes:
  • the first cavity 51 is formed on the side of the first substrate 10 away from the piezoelectric sensing film (the bottom surface of the first substrate) through an etching process, and the bottom of the first cavity 51 exposes the The bottom surface of the cushion layer 20.
  • a second substrate 50 is provided and bonded to the bottom surface of the first substrate 10 to seal the first cavity 51.
  • the method further includes: thinning the bottom surface of the first substrate 10 so that the thickness of the first substrate 10 is 0.5-5 microns; the thickness of the second substrate 50 is 300 -500 microns.
  • the acoustic reflection structure is a Bragg reflection layer, and forming the Bragg reflection layer includes:
  • At least two sets of staggered first acoustic impedance layers and second acoustic impedance layers are formed at the bottom of the second cavity, and the hardness of the first acoustic impedance layer is higher than the hardness of the second acoustic impedance layer, wherein
  • the material of the first acoustic impedance layer is composed of metal including tungsten or a medium including silicon carbide and diamond, and the second acoustic impedance layer includes silicon oxide or silicon nitride.
  • An embodiment of the present invention also provides a surface acoustic wave resonator, including the above-mentioned composite substrate.
  • a surface acoustic wave resonator including the above-mentioned composite substrate.
  • the polycrystalline piezoelectric sensing film has higher crystallinity and higher piezoelectric coupling coefficient than the amorphous piezoelectric sensing film, thereby improving the performance of the surface acoustic wave filter;
  • the polycrystalline material itself or the acoustic wave reflection layer is formed between the first substrate and the polycrystalline material.
  • the longitudinal sound wave is transmitted to the acoustic wave reflection layer, it is reflected back into the piezoelectric sensing film, which reduces the energy loss of the sound wave and improves The Q value of the resonator.

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

Abstract

本发明提供了一种复合基板及其制造方法、表声波谐振器及其制造方法，其中复合基板的制造方法包括：提供第一基板；在所述第一基板上沉积衬垫层，所述衬垫层至少包括多晶材料层；在所述多晶材料层上通过物理或化学沉积方法沉积用于产生声波谐振的压电感应薄膜；对所述压电感应薄膜进行再结晶退火处理，使所述压电感应薄膜达到多晶态，其中所述结晶退火包括升温过程和冷却过程，所述升温过程包括对所述压电感应薄膜进行升温使所述压电感应薄膜达到熔融状态。所述复合基板包括：第一基板；衬垫层，位于所述第一基板上表面，所述衬垫层至少包括多晶材料层；用于产生声波谐振的压电感应薄膜，位于所述多晶材料层上方，所述压电感应膜为多晶态。

Description

一种复合基板及其制造方法、表声波谐振器及其制造方法 技术领域
本发明涉及半导体器件制造领域，尤其涉及一种复合基板及其制造方法和表声波谐振器及其制造方法。
 背景技术
随着移动通信技术的发展，移动数据传输量也迅速上升。因此，在频率资源有限以及应当使用尽可能少的移动通信设备的前提下，提高无线基站、微基站或直放站等无线功率发射设备的发射功率成了必须考虑的问题，同时也意味着对移动通信设备前端电路中滤波器功率的要求也越来越高。
目前，无线基站等设备中的大功率滤波器主要是以腔体滤波器为主，其功率可达上百瓦，但是这种滤波器的尺寸太大。也有的设备中使用介质滤波器，其平均功率可达5瓦以上，这种滤波器的尺寸也很大。由于尺寸大，所以这腔体滤波器无法集成到射频前端芯片中。
 技术问题
目前，无线基站等设备中的大功率滤波器主要是以腔体滤波器为主，其功率可达上百瓦，但是这种滤波器的尺寸太大。也有的设备中使用介质滤波器，其平均功率可达5瓦以上，这种滤波器的尺寸也很大。由于尺寸大，所以这腔体滤波器无法集成到射频前端芯片中。
基于半导体微加工工艺技术的薄膜滤波器中一种主要滤波器为表面声波谐振器（SAW）。现有技术中，表面声波谐振器所用的压电基板通常为硅基板与单晶压电晶圆键合减薄后而形成。然而，单晶压电晶圆材料非常脆，在半导体工艺中极易发生破裂，工艺菜单需要特殊的设计，降低了生产效率。而且目前最大的圆片尺寸还停留在6寸，甚至有许多滤波器厂家的工艺线使用的还是4寸工艺，单片晶圆生产的滤波器芯片数量较少。另外，单晶圆片成本比较高，导致声表面波滤波器的成本不能进一步降低。
因此如何解决压电晶圆在工艺中碎裂，提高基板的生产效率，降低成本是目前面临的问题。
 技术解决方案
本发明揭示了一种复合基板及其制造方法和表声波谐振器及其制造方法，以解决压电感应薄膜晶片在制作过程中易碎裂、成本高，效率低的问题。
为解决上述技术问题，本发明提供了一种复合基板的制造方法，包括：
提供第一基板；
在所述第一基板上沉积衬垫层，所述衬垫层至少包括多晶材料层；
在所述多晶材料层上通过物理或化学沉积方法沉积用于产生声波谐振的压电感应薄膜；
对所述压电感应薄膜进行再结晶退火处理，使所述压电感应薄膜达到多晶态，其中所述结晶退火包括升温过程和冷却过程，所述升温过程包括对所述压电感应薄膜进行升温使所述压电感应薄膜达到熔融状态。
本发明还提供了一种复合基板，包括：
第一基板；
衬垫层，位于所述第一基板上表面，所述衬垫层至少包括多晶材料层；
用于产生声波谐振的压电感应薄膜，位于所述多晶材料层上方，所述压电感应膜为多晶态。
本发明还提供了一种表声波谐振器，包括上述的复合基板。
本发明还提供了一种表声波谐振器的制造方法，包括：上述的复合基板，所述制造方法还包括：
提供所述复合基板；
在所述压电感应薄膜上形成第一叉指换能器和第二叉指换能器。
 
本发明的有益效果在于：
 有益效果
本发明的有益效果在于：
现有技术中普通使用单晶作为表面声波谐振器的压电薄膜，并没有使用多晶作为表面声波谐振器的压电薄膜，主要是因为，业界普遍认为多晶的压电膜不利于声波的传播会影响谐振器的性能。但是，发明人发现：尽管多晶压电薄膜由单晶颗粒拼成，单晶颗粒不会整齐排列，没有形成一致晶向，但是压电薄膜的晶向对压电性能的影响非常小，因此，本方案里形成的多晶压电薄膜与单晶薄膜相比，制作的器件性能是一致的。本方案中，在基板上形成多晶材料层，所述多晶材料层具有较好的晶向，使沉积其上的压电感应薄膜，经过通过退火工艺后，得到较好晶向的、多晶态的压电感应薄膜。这种在基板上形成多晶压电感应薄膜的工艺相对于传统的将压电晶片键合在基板上的方法，避免了压电晶体碎裂、生产效率低、成本高的问题。通过沉积后再结晶后形成多晶压电薄膜，相对于现有单晶的压电薄膜生长工艺简单，成本低；而且，由于多晶压电膜相对于单晶压电膜结构强度更好，不容易碎裂；另外，沉积和退火技术对晶圆尺寸没有限制，可以适用于6英寸、8英寸等生产工艺。而且，由于多晶颗粒的应力方向不集中，不会造成单一方向的应力很大，与单晶相比，大大降低了压电薄膜发生碎裂的风险。
进一步地，多晶的压电薄膜的表面粗糙指数小于10nm，平整度很高，对于多晶压电薄膜，可以尽量减少声波能量散射。
进一步地，多晶材料本身或者在基板和多晶材料之间形成声波反射层，当纵向声波传输至声波反射层时，被反射回压电感应薄膜内，减少了声波能量损失，提高了谐振器的Q值。
进一步地，通过对结晶后的压电感应薄膜的表面进行抛光处理和离子束修整，提高了压电感应薄膜的表面平整度，提高了压电感应薄膜的压电特性。
 附图说明
通过结合附图对本发明示例性实施例进行更详细的描述，本发明的上述以及其它目的、特征和优势将变得更加明显，在本发明示例性实施例中，相同的参考标号通常代表相同部件。
图1示出了根据本发明一实施例的一种复合基板制造方法的流程图。
图2至图4示出了根据本发明一实施例的一种复合基板的结构示意图。
图5示出了根据本发明一实施例的一种表声波谐振器的结构示意图。
图6示出了根据本发明另一实施例的一种表声波谐振器的结构示意图。
附图标记说明：
10-第一基板；20-衬垫层；30-压电感应薄膜；41-第一叉指换能器；42-第二叉指换能器；50-第二基板；51-第一空腔。
 本发明的实施方式
以下结合附图和具体实施例对本发明作进一步详细说明。根据下面的说明和附图，本发明的优点和特征将更清楚，然而，需说明的是，本发明技术方案的构思可按照多种不同的形式实施，并不局限于在此阐述的特定实施例。附图均采用非常简化的形式且均使用非精准的比例，仅用以方便、明晰地辅助说明本发明实施例的目的。
应当明白，当元件或层被称为“在...上”、“与...相邻”、“连接到”或“耦合到”其它元件或层时，其可以直接地在其它元件或层上、与之相邻、连接或耦合到其它元件或层，或者可以存在居间的元件或层。相反，当元件被称为“直接在...上”、“与...直接相邻”、“直接连接到”或“直接耦合到”其它元件或层时，则不存在居间的元件或层。应当明白，尽管可使用术语第一、第二、第三等描述各种元件、部件、区、层和/或部分，这些元件、部件、区、层和/或部分不应当被这些术语限制。这些术语仅仅用来区分一个元件、部件、区、层或部分与另一个元件、部件、区、层或部分。因此，在不脱离本发明教导之下，下面讨论的第一元件、部件、区、层或部分可表示为第二元件、部件、区、层或部分。
空间关系术语例如“在...下”、“在...下面”、“下面的”、“在...之下”、“在...之上”、“上面的”等，在这里可为了方便描述而被使用从而描述图中所示的一个元件或特征与其它元件或特征的关系。应当明白，除了图中所示的取向以外，空间关系术语意图还包括使用和操作中的器件的不同取向。例如，如果附图中的器件翻转，然后，描述为“在其它元件下面”或“在其之下”或“在其下”元件或特征将取向为在其它元件或特征“上”。因此，示例性术语“在...下面”和“在...下”可包括上和下两个取向。器件可以另外地取向(旋转90度或其它取向)并且在此使用的空间描述语相应地被解释。
在此使用的术语的目的仅在于描述具体实施例并且不作为本发明的限制。在此使用时，单数形式的“一”、“一个”和“所述/该”也意图包括复数形式，除非上下文清楚指出另外的方式。还应明白术语“组成”和/或“包括”，当在该说明书中使用时，确定所述特征、整数、步骤、操作、元件和/或部件的存在，但不排除一个或更多其它的特征、整数、步骤、操作、元件、部件和/或组的存在或添加。在此使用时，术语“和/或”包括相关所列项目的任何及所有组合。
如果本文的方法包括一系列步骤，且本文所呈现的这些步骤的顺序并非必须是可执行这些步骤的唯一顺序，且一些的步骤可被省略和/或一些本文未描述的其他步骤可被添加到该方法。若某附图中的构件与其他附图中的构件相同，虽然在所有附图中都可轻易辨认出这些构件，但为了使附图的说明更为清楚，本说明书不会将所有相同构件的标号标于每一图中。
实施例1
本发明一实施例提供了一种复合基板的制造方法，图1示出了根据本发明一实施例的一种复合基板制造方法的流程图，参照图1，复合基板的制造方法包括：
S01：提供第一基板；
S02：在所述第一基板上沉积衬垫层，所述衬垫层至少包括多晶材料层；
S03：在所述多晶材料层上通过物理或化学沉积方法沉积用于产生声波谐振的压电感应薄膜；
S04：对所述压电感应薄膜进行再结晶退火处理，使所述压电感应薄膜达到多晶态，其中所述结晶退火包括升温过程和冷却过程，所述升温过程包括对所述压电感应薄膜进行升温使所述压电感应薄膜达到熔融状态。
图2至图4示出了根据本发明一实施例的一种复合基板制造方法的不同阶段的结构示意图，参考图2至图4，复合基板的制造方法包括：
参考图2，执行步骤S01：提供第一基板10；
第一基板10的材质选择适用半导体工艺的材料，可以为以下所提到的材料中的至少一种：硅(Si)、锗(Ge)、锗硅(SiGe)、碳硅(SiC)、碳锗硅(SiGeC)、砷化铟(InAs)、砷化镓(GaAs)、磷化铟(InP)或者其它III/V化合物半导体，或者为介质体上硅(SOI)、介质体上层叠硅(SSOI)、介质体上层叠锗化硅(S-SiGeOI)、介质体上锗化硅(SiGeOI)以及介质体上锗(GeOI)，或者还可以为双面抛光硅片(Double Side Polished Wafers，DSP)，也可为氧化铝等的陶瓷基板、石英或玻璃基板等。
本实施例中，第一基板10的材质为阻值大于10KOhm.cm的P型硅。选择高阻值的基板材料的原因为：当第一基板上方有通有交流电时，交流电产生电磁波，电磁波辐射损耗一部分电能，在低频条件下，辐射损耗较小，但是在高频条件下，辐射损耗增多，采用高阻值的基板材料，可以减少电磁波辐射，减少电能损耗。
参考图3，执行步骤S02：在所述第一基板10上沉积衬垫层20，所述衬垫层20至少包括多晶材料层。
多晶材料层具有较好的晶向，在后期工艺中，对形成的压电感应薄膜进行结晶时，压电感应薄膜按照结晶材料层的晶向进行结晶。所述多晶材料层的材料包括多晶氧化铝、多晶二氧化硅或多晶碳化硅。本实施例中，衬垫层20为多晶氧化铝。所述多晶材料层具有较好的晶向，使沉积其上的压电感应薄膜，经过通过退火工艺后，得到较好晶向的、多晶态的压电感应薄膜。这种在基板上形成多晶压电感应薄膜的工艺相对于传统的将压电晶片键合在基板上的方法，避免了压电晶体碎裂、生产效率低、成本高的问题。
在所述第一基板10上沉积衬垫层20（本实施例中沉积多晶材料层）的方法包括：通过物理气相沉积或者化学气相沉积在第一基板10上沉积形成厚度为2000埃~10000埃的多晶材料层。多晶材料层的厚度不能太薄，否则多晶层本身的质量不好，影响在后期工艺中，形成在其上面的压电感应薄膜的质量；而且，多晶材料层如果作为声波反射层也需要达到一定厚度。多晶层也不需要太厚，否则影响生产效率。
在另一个实施例中，所述衬垫层20还包括声波反射层，声波反射层形成于所述多晶材料层和第一基板10之间。声波反射层与后期工艺中形成的压电感应薄膜具有较大的阻抗失配，当声波传输至声波反射层时，声波反射层将声波反射回压电感应薄膜内，减少了声波的能量损失。声波反射层的材料包括：氧化铝、二氧化硅、氮化硅或碳化硅。
在所述第一基板10上沉积衬垫层20（包括声波反射层和多晶材料层）的方法包括：通过物理气相沉积或者化学气相沉积在第一基板10上沉积形成厚度为2000埃~10000埃的声波反射层。在声波反射层上，通过物理气相沉积或者化学气相沉积方法形成厚度为2000埃~10000埃的多晶材料层。形成多晶材料层的方法属于现有技术，此处不在赘述。
需要说明的是所述声波反射层和所述多晶材料层可以为同一层，此时所述衬垫层的材料可以为多晶氧化铝、多晶二氧化硅或多晶碳化硅。
参照图4，执行步骤S03：在所述多晶材料层上通过物理或化学沉积方法沉积用于产生声波谐振的压电感应薄膜30。
通过物理气相沉积的方法将压电感应薄膜材料沉积在多晶材料层上，压电感应薄膜材料的厚度范围通常为0.01到10微米之间，本实施例中厚度范围为0.4um到5um。压电感应薄膜材料的厚度选择主要考虑两个方面，一方面能够实现谐振器性能，另一方面工艺的稳定性可控。物理气相沉积方法包括真空蒸镀、溅射镀、离子镀。物理气相沉积所用的压电材料的靶材纯度大于99.99%，以保证沉积的压电感应薄膜具有较少的杂质或缺陷，确保谐振器和滤波器良率达到可以量产的目标值。形成的压电感应薄膜30为微晶或非晶态。本实施例中沉积的压电感应薄膜30用于表声波谐振器。压电感应薄膜30的材料可以是铌酸锂、钽酸锂、四硼酸锂，锗酸铋，硅酸镓镧，正磷酸铝或铌酸钾中的一种或它们的组合。
当沉积铌酸锂压电感应薄膜时，所选用的溅射靶材是以醋酸锂与五氧化二钽为原料烧结而成，溅射离子源所用气体为氩气。
继续参照图4，执行步骤S04：对所述压电感应薄膜30进行再结晶退火处理，使所述压电感应薄膜30达到多晶态，其中所述结晶退火包括升温过程和冷却过程，所述升温过程包括对所述压电感应薄膜30进行升温使所述压电感应薄膜30达到熔融状态。
采用使所述压电感应薄膜30达到熔融状态的温度对所述压电感应薄膜20进行再结晶退火处理。再结晶退火处理的方法包括两种，一种为对第一基板、衬垫层、压电感应薄膜整体均匀加热，如采用炉管对所述压电感应薄膜30、所述衬垫层20、所述第一基板10整体加热使所述压电感应薄膜30达到熔融状态，使所述压电感应薄膜30再结晶。另一种为对压电感应薄膜30局部加热，如采用激光对所述压电感应薄膜30进行扫描加热使所述压电感应薄膜30达到熔融状态，使所述压电感应薄膜30再结晶。
第一种再结晶退火方法具体包括：将沉积有压电感应薄膜30的第一基板10放入高温炉内，如卧式炉、立式炉、快速热处理（RTP）。在1100~1200度的温度下加热2到5分钟。
第二种再结晶退火方法具体包括：在真空、氮气或氧气氛围中，以0.8-15焦耳每平方厘米的脉冲激光，激光频率为1~10KHz，作用于所述压电感应薄膜5秒到20秒（不同的压电感应薄膜作用时间不同），以扫描形式使压电感应薄膜的温度加热至1000-1400，达到熔融态，重新结晶。
本实施例中，压电感应薄膜30的材质为铌酸锂或钽酸锂，采用炉管退火对所述压电感应薄膜30进行再结晶退火处理包括：对所述第一基板10、衬垫层20、压电感应薄膜30整体均匀加热至1100度到1300度，加热时间5至30秒，再冷却至室温，冷却的降温速率低于每秒5摄氏度，以避免压电感应薄膜30起皮或碎裂。
在本实施例中，压电感应薄膜30再结晶完成后还包括：通过机械或机械化学抛光工艺对压电感应薄膜30的上表面进行抛光处理，如通过化学机械研磨（CMP）。抛光处理后的所述压电感应薄膜30的表面粗糙指数低于10纳米。对所述压电感应薄膜30的上表面进行抛光处理后还包括：通过离子束修整工艺对所述压电感应薄膜30的上表面进行修整，修整后的所述压电感应薄膜30的表面厚度均匀性小于2%。离子束的修整精度可以达到纳米级，可以实现对压电感应薄膜30局部和整体表面高度进行修整。修整后的整片基板上的压电感应薄膜的高度达到一致，提高了相邻器件的性能一致性，提高了谐振器的良率。
本实施例中，离子束修整工艺采用如下参数：离子束电流为25毫安到200毫安，扫描时间为30秒到10分钟。
通过对结晶后的压电感应薄膜的表面进行抛光处理和离子束修整，提高了压电感应薄膜的表面平整度，提高了压电感应薄膜的压电特性。
实施例2
本发明一实施例提供了一种复合基板，图4示出了根据本发明一实施例的一种复合基板的结构示意图，请参照图4，所述复合基板包括：
第一基板10；
衬垫层20，位于所述第一基板10上表面，所述衬垫层20至少包括多晶材料层；
用于产生声波谐振的压电感应薄膜30，位于所述多晶材料层上方，所述压电感应膜为30多晶态。
本实施例中，第一基板10的材质为阻值大于10KOhm.cm的P型硅。选择高阻值的基板材料的原因为，当第一基板上方有通有交流电时，交流电产生电磁波，电磁波辐射损耗一部分电能，在低频条件下，辐射损耗较小，但是在高频条件下，辐射损耗增多，采用高阻值的基板材料，可以减少电磁波辐射，减少电能损耗。
本实施例中，所述衬垫层20为单层膜结构，即为多晶材料层，所述多晶材料层包括多晶氧化铝、多晶二氧化硅或多晶碳化硅。
在另一个实施例中，所述衬垫层还包括声波反射层，所述声波反射层设置于所述第一基板与所述多晶材料层之间。所述声波反射层的材料包括氧化铝、二氧化硅、氮化硅或碳化硅。
需要说明的是，所述声波反射层和所述多晶材料层可以为同一层，此时所述衬垫层的材料包括多晶氧化铝、多晶二氧化硅或多晶碳化硅。声波反射层的作用：当纵向声波传输至声波反射层时，被反射回压电感应薄膜内，减少了声波能量损失，提高了谐振器的Q值。
在另一个实施例中，所述第一基板还包括声反射结构，所述声反射结构包括空腔或布拉格反射层。所述声反射结构用于将压电片体传入第一基板的纵向声波反射或压电片内，进一步减少声波的能量损失。
实施例3
本发明一实施例还提供了一种表声波谐振器的制造方法，图5示出了根据本发明一实施例的一种表声波谐振器的结构图，参考图5，所述方法包括：
提供所述复合基板；
在所述压电感应薄膜30上形成第一叉指换能器41和第二叉指换能器42。
在所述压电感应薄膜30的表面上方形成第一导电薄膜。可以通过磁控溅射、蒸镀等物理气相沉积或者化学气相沉积方法在压电感应薄膜的表面上方形成第一导电薄膜。第一导电薄膜的材质可以使用任意合适的导电材料，例如：由钼（Mo）、铝（Al）、铜（Cu）、钨（W）、钽（Ta）、铂（Pt）、钌（Ru）、铑（Rh）、铱（Ir）、铬（Cr）、钛（Ti）、金(Au)、锇(Os)、铼(Re)、钯(Pd)、铂金、镍等金属中一种制成或由上述合金制成。
图形化所述第一导电薄膜，形成第一叉指换能器41和第二叉指换能器42。本实施例中，制作的谐振器为表面声波谐振器（SAW），图形化所述第一导电薄膜的方法包括干法刻蚀、湿法刻蚀。其中第一叉指换能器41包含多个相互平行相间的第一导电叉指，第一叉指换能器41包含多个相互平行相间的第二导电叉指。第一叉指换能器41和第二叉指换能器42相互平行包括两种情况：一种为第一导电叉指和第二导电叉指相互平行且交错设置，另一种为第一叉指换能器41和第二叉指换能器42分开设置，第一导电叉指和第二导电叉指相互平行，但不相互交错，本实施例按照第一种情况设置。当然第一叉指换能器41和第二叉指换能器42也可以不平行，只要不相交即可。
在一个实施例中，所述复合基板形成有声反射结构，所述第一叉指换能器和第二叉指换能器形成于所述声反射结构围成的区域上方。
参考图6，在一个实施例中，所述声反射结构为第一空腔51，形成所述第一空腔51包括：
在所述第一基板10与所述压电感应薄膜远离的一面（第一基板的底面）通过刻蚀工艺形成所述第一空腔51，所述第一空腔51的底部暴露出所述衬垫层20的底面。
提供第二基板50，键合于所述第一基板10的底面，密封所述第一空腔51。
形成所述第一空腔51之前还包括：对所述第一基板10的底面进行减薄，使所述第一基板10的厚度为0.5-5微米；所述第二基板50的厚度为300-500微米。
在另一个实施例中，所述声反射结构为布拉格反射层，形成所述布拉格反射层包括：
在所述第一基板的底面通过刻蚀工艺形成第二空腔，所述第二空腔的底部暴露出所述衬垫层；
在所述第二空腔的底部形成至少两组交错的第一声阻抗层和第二声阻抗层，所述第一声波阻抗层的硬度高于所述第二声波阻抗层的硬度，其中所述第一声波阻抗层的材料由包括钨在内的金属或包括碳化硅、金刚石在内的介质构成，所述第二声阻抗层包括氧化硅或氮化硅。
实施例4
本发明一实施例还提供了一种表声波谐振器，包括上述的复合基板。表声波谐振器的结构参照实施例3的制造表声波谐振器的方法部分。此处不在赘述。
多晶态的压电感应薄膜相对于非晶态的压电感应薄膜具有较高的结晶度和较高的压电耦合系数，从而提高了声表面波滤波器的性能；
进一步地，多晶材料本身或者在第一基板和多晶材料之间形成声波反射层，当纵向声波传输至声波反射层时，被反射回压电感应薄膜内，减少了声波能量损失，提高了谐振器的Q值。
 
需要说明的是，本说明书中的各个实施例均采用相关的方式描述，各个实施例之间相同相似的部分互相参见即可，每个实施例重点说明的都是与其他实施例的不同之处。尤其，对于结构实施例而言，由于其基本相似于方法实施例，所以描述的比较简单，相关之处参见方法实施例的部分说明即可。
上述描述仅是对本发明较佳实施例的描述，并非对本发明范围的任何限定，本发明领域的普通技术人员根据上述揭示内容做的任何变更、修饰，均属于权利要求书的保护范围。

Claims (24)

  1. 一种复合基板的制造方法，其特征在于，包括：
    提供第一基板；
    在所述第一基板上沉积衬垫层，所述衬垫层至少包括多晶材料层；
    在所述多晶材料层上通过物理或化学沉积方法沉积用于产生声波谐振的压电感应薄膜；
    对所述压电感应薄膜进行再结晶退火处理，使所述压电感应薄膜达到多晶态，其中所述结晶退火包括升温过程和冷却过程，所述升温过程包括对所述压电感应薄膜进行升温使所述压电感应薄膜达到熔融状态。
  2. 如权利要求1所述的复合基板的制造方法，其特征在于，所述对所述压电感应薄膜进行再结晶退火处理后还包括：
    通过机械或机械化学抛光工艺对所述压电感应薄膜的上表面进行抛光处理，抛光处理后的所述压电感应薄膜的表面粗糙指数低于10纳米。
  3. 如权利要求2述的复合基板的制造方法，其特征在于，所述对所述压电感应薄膜的上表面进行抛光处理后还包括：
    通过离子束修整工艺对所述压电感应薄膜的上表面进行修整，修整后的所述压电感应薄膜的表面厚度均匀性小于2%。
  4. 如权利要求1所述的复合基板的制造方法，其特征在于，所述压电感应薄膜的材质包括铌酸锂、钽酸锂、四硼酸锂，锗酸铋，硅酸镓镧，正磷酸铝或铌酸钾中的一种或它们的组合。
  5. 如权利要求1所述的复合基板的制造方法，其特征在于，所述压电感应薄膜的厚度为0.01-10微米。
  6. 如权利要求1所述的复合基板的制造方法，其特征在于，所述再结晶退火处理包括：
    炉管退火，对所述第一基板、第一基板上沉积的衬垫层和压电感应薄膜整体均匀加热；
    或，
    包括激光退火，对所述压电感应薄膜局部加热使之再结晶。
  7. 如权利要求6所述的复合基板的制造方法，其特征在于，所述激光退火包括：在真空、氮气或氧气氛围中，对所述压电感应薄膜进行激光退火。
  8. 如权利要求6所述的复合基板的制造方法，其特征在于，所述压电感应薄膜的材质为铌酸锂或钽酸锂，通过所述炉管退火对所述压电感应薄膜进行再结晶退火处理包括：
    对所述第一基板、衬垫层、压电感应薄膜整体均匀加热至1100-1300度，加热时间5至30秒，再冷却至室温，所述冷却的降温速率低于每秒5摄氏度。
  9. 如权利要求1所述的复合基板的制造方法，其特征在于，形成所述压电感应薄膜包括：
    采用纯度大于99.99%的靶材，通过物理气相沉积法形成微晶或非晶态的所述压电感应薄膜。
  10. 如权利要求1所述的复合基板的制造方法，其特征在于，所述多晶材料层包括多晶氧化铝、多晶二氧化硅或多晶碳化硅，。
  11. 如权利要求1所述的复合基板的制造方法，其特征在于，所述衬垫层还包括声波反射层，所述声波反射层设置于所述第一基板与所述多晶材料层之间。
  12. 如权利要求11所述的复合基板的制造方法，其特征在于，所述声波反射层的材料包括氧化铝、二氧化硅、氮化硅或碳化硅，或者它们的组合。
  13. 如权利要求11所述的复合基板的制造方法，其特征在于，所述声波反射层和所述多晶材料层为同一层，所述衬垫层的材料包括多晶氧化铝、多晶二氧化硅或多晶碳化硅。
  14. 一种复合基板，其特征在于，包括：
    第一基板；
    衬垫层，位于所述第一基板上表面，所述衬垫层至少包括多晶材料层；
    用于产生声波谐振的压电感应薄膜，位于所述多晶材料层上方，所述压电感应膜为多晶态。
  15. 如权利要求14所述的复合基板，其特征在于，所述多晶材料层包括多晶氧化铝、多晶二氧化硅或多晶碳化硅。
  16. 如权利要求14所述的复合基板的制造方法，其特征在于，所述压电感应薄膜的厚度为0.01-10微米。
  17. 如权利要求14所述的复合基板的制造方法，其特征在于，所述压电感应薄膜的表面厚度均匀性小于2%。
  18. 如权利要求14所述的复合基板，其特征在于，所述衬垫层还包括声波反射层，所述声波反射层设置于所述第一基板与所述多晶材料层之间。
  19. 如权利要求18所述的复合基板，其特征在于，所述声波反射层的材料包括氧化铝、二氧化硅、氮化硅或碳化硅。
  20. 如权利要求18所述的复合基板，其特征在于，所述声波反射层和所述多晶材料层为同一层，所述衬垫层的材料包括多晶氧化铝、多晶二氧化硅或多晶碳化硅。
  21. 如权利要求16所述的复合基板，其特征在于，所述第一基板包括声反射结构。
  22. 如权利要求21所述的复合基板，其特征在于，所述声反射结构包括空腔或布拉格反射层。
  23. 一种表声波谐振器，其特征在于，包括权利要求14至22任一项所述的复合基板。
  24. 一种表声波谐振器的制造方法，利用权利要求14至20任一项所述的复合基板，其特征在于，所述制造方法包括：
    提供所述复合基板；
    在所述压电感应薄膜上形成第一叉指换能器和第二叉指换能器。
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JPH08154033A (ja) * 1994-11-29 1996-06-11 Sumitomo Electric Ind Ltd ダイヤモンド基材および表面弾性波素子
US20030011280A1 (en) * 2000-08-09 2003-01-16 Hideaki Nakahata Surface acoustic wave device and substrate thereof
CN101777622A (zh) * 2010-01-12 2010-07-14 郑州大学 LiNbO3/SiO2/金刚石多层压电膜及其制备方法

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