CN117595823A - Film bulk acoustic resonator, electronic equipment and manufacturing method thereof - Google Patents

Film bulk acoustic resonator, electronic equipment and manufacturing method thereof Download PDF

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Publication number
CN117595823A
CN117595823A CN202311611746.1A CN202311611746A CN117595823A CN 117595823 A CN117595823 A CN 117595823A CN 202311611746 A CN202311611746 A CN 202311611746A CN 117595823 A CN117595823 A CN 117595823A
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substrate
electrode
hole
layer
forming
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Inventor
唐滨
赖志国
杨清华
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Suzhou Huntersun Electronics Co Ltd
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Suzhou Huntersun Electronics Co Ltd
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Priority to CN202311611746.1A priority Critical patent/CN117595823A/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
    • H03H9/15—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
    • 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
    • H03H9/54—Filters comprising resonators of piezoelectric or electrostrictive material
    • H03H9/56—Monolithic crystal filters
    • H03H9/564—Monolithic crystal filters implemented with thin-film techniques
    • 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
    • H03H9/54—Filters comprising resonators of piezoelectric or electrostrictive material
    • H03H9/58—Multiple crystal filters
    • H03H9/582—Multiple crystal filters implemented with thin-film techniques
    • 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

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

Abstract

The present disclosure relates to a thin film bulk acoustic resonator, an electronic device, and a method of manufacturing the same, the method of manufacturing the thin film bulk acoustic resonator including: providing a first substrate, forming a piezoelectric layer on a first surface of the first substrate, and forming a second electrode on the piezoelectric layer; thinning the first substrate, patterning the second surface of the thinned first substrate, and forming a first through hole exposing the piezoelectric layer in the first substrate; forming a first electrode in a first through hole of a first region of the first substrate, wherein the first electrode, the piezoelectric layer and the second electrode form a structural functional layer; forming a first support layer on a second surface of the first substrate, patterning the first support layer, and forming a third via hole in the first support layer corresponding to the first region of the first substrate; a third substrate is bonded on the patterned first support layer.

Description

Film bulk acoustic resonator, electronic equipment and manufacturing method thereof
Technical Field
The present disclosure relates to the field of electronics, and more particularly, to a thin film bulk acoustic resonator, an electronic device, and a method of manufacturing the same.
Background
A thin film bulk acoustic resonator is a common element in a radio frequency device, and fig. 1 is a schematic structural diagram of a conventional thin film bulk acoustic resonator. As shown in fig. 1, the thin film bulk acoustic resonator includes a substrate 100, a cavity 101, a lower electrode 102, a piezoelectric layer 103, and an upper electrode 104, wherein the lower electrode 102, the upper electrode 104, and the piezoelectric layer 103 form a sandwich structure. In the process of manufacturing the thin film bulk acoustic resonator, the cavity 101 is formed in the substrate 100, then the sacrificial material is filled in the cavity 101, then the lower electrode material is deposited and patterned to form the lower electrode 102, then the piezoelectric layer 103 is formed on the lower electrode 102, and then the sacrificial material is removed to release the cavity 101 after other manufacturing processes are completed, and the cavity 101 serves as an acoustic reflection region of the thin film bulk acoustic resonator.
The above-mentioned prior art method for manufacturing a thin film bulk acoustic resonator has the following technical problems: first, when filling the sacrificial material, the sacrificial material is generally conformally deposited on the upper surface of the substrate 100, and thus a planarization process such as chemical mechanical polishing is required on the upper surface of the substrate 100 to remove the sacrificial material outside the cavity 101. Thus, the device having the cavity 101 requires a plurality of complicated process steps in manufacturing, and the polishing rates of the sacrificial material and the substrate material are not uniform in the chemical mechanical polishing process due to the difference of the sacrificial material and the substrate material and the selective setting of the polishing liquid and the polishing pressure in the chemical mechanical polishing process, so that the upper surface of the sacrificial material in the cavity 101 protrudes from the upper surface of the substrate 100 or is lower than the upper surface of the substrate 100 after polishing, thereby generating protrusions or depressions. Defects of the structure can accumulate in different layers layer by layer, and further the growth of subsequent structural layers and the operation of devices at later stages are not facilitated. Furthermore, the process of releasing the sacrificial material to form the cavity 101 often results in increased process difficulty and the potential for unclean release of the sacrificial material.
Secondly, in the existing manufacturing method, as the piezoelectric layer is deposited and grown on the patterned lower electrode, cracks are easily generated on the piezoelectric layer due to the existence of the patterned lower electrode, and the crystal performance of the piezoelectric layer is not well ensured.
Therefore, the existing filter preparation process has the technical problems of complex flow, poor compatibility of piezoelectric materials, high process difficulty, poor structural stability of devices, high preparation cost, low yield and the like.
Disclosure of Invention
The present disclosure is directed to the above-mentioned technical problems, and improves the process flow of the thin film bulk acoustic resonator, which can overcome the above-mentioned technical problems existing in the prior art.
A brief summary of the disclosure will be presented below in order to provide a basic understanding of some aspects of the disclosure. It should be understood that this summary is not an exhaustive overview of the disclosure. It is not intended to identify key or critical elements of the disclosure or to delineate the scope of the disclosure. Its purpose is to present some concepts in a simplified form as a prelude to the more detailed description that is discussed later.
In one aspect, the disclosure provides a method for manufacturing a thin film bulk acoustic resonator, including: providing a first substrate, forming a piezoelectric layer on a first surface of the first substrate, and forming a second electrode on the piezoelectric layer; thinning the first substrate, patterning the second surface of the thinned first substrate, and forming a first through hole exposing the piezoelectric layer in the first substrate; forming a first electrode in a first through hole of a first region of the first substrate, wherein the first electrode, the piezoelectric layer and the second electrode form a structural functional layer; forming a first support layer on a second surface of the first substrate, patterning the first support layer, and forming a third via hole in the first support layer corresponding to the first region of the first substrate; a third substrate is bonded on the patterned first support layer.
Further, a surface of the first region of the third substrate opposite the second surface of the first substrate is etched to form a recess.
Further, a second support layer is formed, the second support layer is patterned, a fourth via is formed in the second support layer corresponding to the first region of the third substrate, and a capping layer is formed on the patterned second support layer.
Further, forming a second portion of the first electrode lead-out electrode simultaneously with the forming of the second electrode; etching the piezoelectric layer after forming the first through hole and before depositing the first electrode material layer, forming a second through hole in the piezoelectric layer, exposing a second part of the first electrode extraction electrode in the second through hole, and forming the second through hole and the first through hole of the second area of the first substrate into a first through hole; and forming a first portion of the first electrode lead-out electrode in the first through hole while forming the first electrode.
Further, in the step of patterning the second support layer, a fifth via hole is formed in the second support layer corresponding to the second region of the third substrate while the fourth via hole is formed, the fifth via hole exposing the second portion of the first electrode lead-out electrode; forming a sixth through hole in the capping layer corresponding to the fifth through hole, the fifth through hole and the sixth through hole forming a second through hole; conductive pillars are formed in the second through holes, bumps are formed on the conductive pillars or conductive pillars are formed in the second through holes, and spacers and bumps are formed on the conductive pillars.
Further, the step of thinning the first substrate includes coating a first layer of bonding material, providing a second substrate, and temporarily bonding a first surface of the second substrate opposite the first surface of the first substrate.
Further, after bonding the third substrate on the patterned first support layer, the second substrate is removed by a de-bonding process.
Further, the step of thinning the first substrate includes removing the first substrate entirely.
Further, etching the third substrate and the first support layer to form a fifth through hole in the third substrate and the first support layer at a position corresponding to the second through hole to expose a first portion of the first electrode lead-out electrode; conductive pillars are formed in the fifth through holes, bumps are formed on the conductive pillars or conductive pillars are formed in the fifth through holes, and spacers and bumps are formed on the conductive pillars.
Further, the structural function layer on the first region of the first support layer is etched, and a through hole is formed in the structural function layer.
Further, trenches are formed at the scribe lines between the dies of adjacent thin film bulk acoustic resonators, and passivation layers are deposited on the sidewalls and bottom of the trenches.
Further, the width of the trench is between the dicing blade width and the dicing street width, and the depth of the trench into the third substrate is 0.1 μm-100 μm.
Another aspect of the present disclosure provides a thin film bulk acoustic resonator fabricated by any one of the foregoing fabrication methods.
Yet another aspect of the present disclosure provides an electronic device comprising the foregoing thin film bulk acoustic resonator.
The thin film bulk acoustic resonator and the preparation process thereof have the following advantages: the method simplifies the process flow of the device, improves the compatibility of piezoelectric materials, reduces the process difficulty and the manufacturing cost, improves the structural stability of the device, improves the yield and the yield, and is convenient for industrial mass production and application.
Drawings
The above and other objects, features and advantages of the present disclosure will be more readily appreciated by reference to the following description of the specific details of the disclosure taken in conjunction with the accompanying drawings. The drawings are only for the purpose of illustrating the principles of the present disclosure. The dimensions and relative positioning of the elements in the figures are not necessarily drawn to scale.
FIG. 1 is a schematic diagram of a structure of a film bulk acoustic resonator in a conventional filter;
fig. 2-4 are schematic structural diagrams of a radio frequency device with a cavity structure provided by the present disclosure;
fig. 5-22 are schematic diagrams illustrating a process flow for fabricating a radio frequency device having a cavity structure according to the present disclosure.
Detailed Description
Exemplary disclosure of the present disclosure will be described hereinafter with reference to the accompanying drawings. In the interest of clarity and conciseness, not all features of an implementation of the present disclosure are described in the specification. It will be appreciated, however, that in the development of any such actual implementation, numerous implementation-specific decisions may be made to achieve the developers' specific goals, and that these decisions may vary from one implementation to another.
Here, it is also to be noted that, in order to avoid obscuring the present disclosure with unnecessary details, only device structures closely related to the scheme according to the present disclosure are shown in the drawings, while other details not greatly related to the present disclosure are omitted.
In general, it should be understood that the drawings and the various elements depicted therein are not drawn to scale. Moreover, the use of relative terms (e.g., "above," "below," "top," "bottom," "upper," and "lower") to describe various elements' relationships to one another should be understood to encompass different orientations of the device and/or elements in addition to the orientation depicted in the figures.
It is to be understood that the present disclosure is not limited to the described embodiments due to the following description with reference to the drawings. Herein, features between different embodiments may be replaced or borrowed, where possible, and one or more features may be omitted in one embodiment, where like reference numerals refer to like parts. It should be understood that the manufacturing steps of the present disclosure are exemplary in embodiments, and that the order of the steps may be varied.
First embodiment
Referring to fig. 2, fig. 2 shows a device structure of a thin film bulk acoustic resonator provided by the present disclosure. As shown in fig. 2, the device structure of the thin film bulk acoustic resonator includes a carrier portion, a functional element portion, a cover portion, and an electrical connection element portion. Wherein the functional component part is arranged on the carrier part, the cover part is arranged on the functional component part, and the electric connection component is used for transmitting electric signals of the functional component part.
The carrier portion includes a third substrate 3000 and a first support layer 3100. Wherein the third substrate 3000 may be, for example, high-resistance silicon, gallium arsenide, indium phosphide, glass, sapphire, aluminum oxide 、 SiC, and the like, is formed of materials compatible with semiconductor processes. It should be noted in particular that when the third substrate 3000 is made of a glass material, its dielectric constant is low, resistance efficiency is high, and in high frequency performanceFurther advantages are achieved.
The first support layer 3100 may be formed of a vertical sidewall profile material in a thicker thickness. Illustratively, the material of the first support layer 3100 may be SU-8 functional polymer, epoxy, polyester, rubber, poly-p-phenylene benzobisoxazole fiber (PBO: poly-p-phenylene benzobisoxazole), or the like.
The first support layer 3100 is formed on a first surface of the third substrate 3000. The third substrate 3000 includes a first region and a second region, wherein the first region of the third substrate 3000 does not have the first support layer 3100 thereon, and the second region of the third substrate 3000 has the first support layer 3100 thereon. The first region of third substrate 3000 and the second region of third substrate 3000 may or may not be coplanar.
The functional component part includes a first substrate 1000, a first electrode 1100, a piezoelectric layer 1200, and a second electrode 1300. Wherein the first substrate 1000 may be, for example, high resistance silicon, gallium arsenide, indium phosphide, glass, sapphire, aluminum oxide 、 SiC, and the like, is formed of materials compatible with semiconductor processes. It should be noted in particular that when the first substrate 1000 is made of a glass material, it has a low dielectric constant, high resistance efficiency, and more advantageous in high-frequency performance.
The first substrate 1000 includes a first region and a second region, and a projection of the first region of the first substrate 1000 onto the first surface of the third substrate 3000 falls within the first region of the third substrate 3000. A first cavity of the acoustic wave reflecting region of the thin film bulk acoustic resonator is provided between the first region of the first substrate 1000 and the first region of the third substrate 3000.
A first electrode 1100 of a thin film bulk acoustic resonator is formed in a first region of the first substrate 1000. The first electrode 1100 may be a single layer or multiple layers, and the first electrode 1100 may be formed of one or more conductive materials, such as various metals compatible with semiconductor processes including tungsten, molybdenum, iridium, aluminum, platinum, ruthenium, niobium, or hafnium. A first portion 5010 of the extraction electrode is formed at the second region of the first substrate 1000. The first portion 5010 of the first electrode lead electrode is electrically connected to the first electrode 1100. The material of the first portion 5010 of the first electrode lead electrode may be the same as the first electrode.
A piezoelectric layer 1200 of a thin film bulk acoustic resonator is formed on the first substrate 1000, the piezoelectric layer 1200 covering at least the first electrode 1100. The piezoelectric layer 1200 may be made of a piezoelectric material compatible with semiconductor processes, such as single crystal aluminum nitride, polycrystalline aluminum nitride, single crystal aluminum scandium nitride, polycrystalline aluminum scandium nitride, or the like.
A second electrode 1300 of the thin film bulk acoustic resonator and a second portion 5020 of the first electrode lead-out electrode are formed on the piezoelectric layer 1200. The projection of the second electrode 1300 onto the first surface of the third substrate 3000 has at least a portion overlapping with the projection of the first electrode 1100 onto the first surface of the third substrate 3000. The projection of the second portion 5020 of the first electrode lead electrode onto the first surface of the third substrate 3000 falls within the second region of the third substrate 3000. The first portion 5010 of the first electrode lead-out electrode and the second portion 5020 of the first electrode lead-out electrode together constitute the first electrode lead-out electrode for use as a signal transmitting terminal of the first electrode 1100. The second electrode 1300 may be a single layer or a plurality of layers, and the material of the second electrode 1300 may be formed of one or more conductive materials, such as various metals compatible with semiconductor processes including tungsten, molybdenum, iridium, aluminum, platinum, ruthenium, niobium, or hafnium. The materials of the first electrode 1100 and the second electrode 1300 may be the same or different. The upper surface of the second portion 5020 of the first electrode lead-out electrode is coplanar with the upper surface of the second electrode 1300, which are the same material. The overlapping portions of the first electrode 1100, the piezoelectric layer 1200, and the second electrode 1300 in the direction perpendicular to the third substrate 3000 constitute structural functional layers of the thin film bulk acoustic resonator.
Further, the functional component part may further include a mass loading layer, a frame structure, etc. formed on the first electrode 1100 and/or the second electrode 1300. Alternatively, a passivation layer may be formed on the second electrode 1300. The mass-loaded layer may be integrally formed with the first electrode 1100 and/or the second electrode 1300 or may be separately formed. The material of the mass-loaded layer may be the same as the material of the first electrode 1100 and/or the second electrode 1300. A passivation layer is coated on the second electrode 1300, and the material of the passivation layer may be the same as that of the piezoelectric layer 1200.
The capping portion includes a capping layer 4000 and a second support layer 4100. The second support layer 4100 is formed on the component functional layer, and the capping layer 4000 is formed on the second support layer 4100. The first surface of the capping layer 4000 is disposed opposite to the first surface of the third substrate 3000. Wherein the second support layer 4100 employs a material that can form vertical sidewall profiles in a thicker thickness. By way of example, the second support layer 4100 may be SU-8 functional polymer, epoxy, polyester, rubber, poly-p-phenylene benzobisoxazole fiber (PBO: poly-p-phenylene benzobisoxazole), or the like, that may be formed to a thicker thickness having a vertical sidewall profile. The materials of the second support layer 4100 and the first support layer 3100 may be the same or different.
The capping layer 4000 is made of a material having good sealing and solder resist effects. Illustratively, it may be selected from SU-8 functional polymers, epoxy resins, poly-p-phenylene benzobisoxazole fibers, polyimide layers, glass frit layers. The capping layer 4000 includes a first region and a second region, wherein the second support layer 4100 is not provided at the first region of the capping layer 4000, and the second support layer 4100 is provided at the second region of the capping layer 4000. The first region of the capping layer 4000 is disposed such that the projection of the structural functional layer onto the first surface of the capping layer 4000 falls within the first region of the capping layer 4000. A second cavity of the thin film bulk acoustic resonator is formed between the first region of the capping layer 4000 and the second electrode 1300.
A through hole is formed in the second support layer 4100 corresponding to and at the second region of the capping layer 4000, a conductive pillar 5030 connected to the second portion 5020 of the first electrode lead-out electrode is formed in the through hole, and a bump 5040 is formed on the conductive pillar 5030. The conductive posts 5030 are preferably made of a metal having excellent conductivity, such as copper, for better electrical signal transmission, and the bumps 5040 may be made of a metal material having a low melting point, such as tin, lead (Pb), or aluminum, for easy melt molding. Further, a spacer layer may be provided between the conductive posts 5030 and the bumps 5040. The spacer layer is selected to provide spacer protection based on the material of the third conductive pillars 5030 and the material of the bumps 5040, such as nickel.
The first electrode extraction electrode, the conductive post 5030, the bump 5040, and the spacer layer (if any) constitute an electrical connection assembly of the thin film bulk acoustic resonator for transmitting electrical signals of the functional assembly portion.
The thin film bulk acoustic resonator provided by the present disclosure may be modified as follows on the basis of the foregoing basic embodiment.
In the first alternative embodiment provided in the present disclosure, the functional component part of the thin film bulk acoustic resonator does not have the first substrate 1000, and the rest of the structural arrangements are the same as those of the basic embodiment, which is not described herein again.
Referring to fig. 3, fig. 3 shows a second alternative embodiment of the device structure of the thin film bulk acoustic resonator provided by the present disclosure. In the second alternative embodiment, a through hole may be formed at the second region of the third substrate 3000 and in the first support layer 3100 at the second region, a conductive post 5030 connected to the second portion 5020 of the first electrode lead-out electrode is formed in the through hole, and a bump 5040 is formed on the conductive post 5030. The remaining configuration may be the same as any of the foregoing embodiments, and will not be described again here.
Referring to fig. 4, fig. 4 shows a third alternative embodiment of the device structure of the thin film bulk acoustic resonator provided by the present disclosure. In a third alternative embodiment provided by the present disclosure, a through hole 1110 is formed in a functional component part of the thin film bulk acoustic resonator so as to allow communication between the first cavity and the second cavity for balancing the pressure between the first cavity and the second cavity. The remaining configuration may be the same as any of the foregoing embodiments, and will not be described again here.
Referring to fig. 5, fig. 5 shows a fourth alternative embodiment of the device structure of the thin film bulk acoustic resonator provided by the present disclosure. In a fourth alternative embodiment provided by the present disclosure, a trench 6000 may be further formed between the die including the thin film bulk acoustic resonator, and a passivation layer 6100 may be filled at least at the sidewalls and the bottom of the trench 6000 for ensuring the air tightness of the chip. Specifically, the width of the groove 6000 is between the dicing blade width and the dicing street width, and the depth of the groove 6000 into the third substrate 3000 is 0.1 μm to 100 μm. The material of the filled passivation layer 6100 may be silicon dioxide, silicon nitride, or the like, which may be adapted to ensure the air tightness of the die. The thickness of the passivation layer 6100 may be set between 1000A-10 um. The remaining configuration may be the same as any of the foregoing embodiments, and will not be described again here.
Compared with the traditional film bulk acoustic resonator, the lower film bulk acoustic resonator provided by the disclosure has the advantages that the compatibility of piezoelectric materials is improved, the lower film bulk acoustic resonator is suitable for monocrystalline and polycrystalline piezoelectric materials, the structural stability of the device is improved, and the product yield is improved.
Second embodiment
The method for fabricating the filter structure according to the first embodiment of the present disclosure will be further described with reference to fig. 6 to 18. In the method of manufacture section, the present disclosure will be described with reference to a filter as an example. Those skilled in the art can use the methods of fabrication disclosed in this disclosure to fabricate other radio frequency devices including the structural functional layers described above in accordance with the spirit and principles of the fabrication methods.
Step 1: as shown in fig. 6, a first substrate 1000 is provided. The first substrate 1000 may be, for example, high resistance silicon, gallium arsenide, indium phosphide, glass, sapphire, aluminum oxide 、 SiC, and the like, is formed of materials compatible with semiconductor processes. Preferably, the first substrate 1000 may be made of a silicon material that is easily removable and inexpensive.
Step 2: as shown in fig. 6, a piezoelectric layer 1200 forming a thin film bulk acoustic resonator is deposited on a first surface of a first substrate 1000, and the piezoelectric layer 1200 may be composed of a piezoelectric material compatible with semiconductor processes, such as single crystal aluminum nitride, polycrystalline aluminum nitride, single crystal aluminum scandium nitride, polycrystalline aluminum scandium nitride, or the like.
Step 3: as shown in fig. 7, a second electrode material layer is deposited on the piezoelectric layer 1200, and the second electrode material layer is patterned to form a second electrode 1300 of the thin film bulk acoustic resonator and a second portion 5020 of the first electrode lead-out electrode. The material of the second electrode 1300 is selected as described above, and will not be described here again.
Step 4: next, as shown in fig. 8, a first bonding material layer 2100 is coated on the first substrate 1000 where the second electrode 1300 and the second portion 5020 of the first electrode lead-out electrode are formed, and the first bonding material layer 2100 should be coated to have a thickness greater than that of the second electrode 1300 and the second portion of the first electrode 1100 lead-out electrode to entirely cover the second electrode 1300 and the second portion of the first electrode 1100 lead-out electrode. The first bonding material layer 2100 may be selected to have a bonding material having high bonding strength, good chemical stability, good flatness, and easy debonding, and exemplary, the first bonding material layer 2100 may be resin, polyester, rubber, or the like. Then, the first bonding material layer 2100 is pre-cured, and the second substrate 2000 is stacked on the first bonding material layer 2100, where the second substrate 2000 plays a role of temporary support in the manufacturing process, and the material of the second substrate 2000 may be a substrate material that is easy to peel. The first surface of the second substrate 2000 is disposed opposite to the first surface of the first substrate 1000. The first substrate 1000 and the second substrate 2000 are temporarily bonded by the first bonding material layer 2100 under heating and pressurizing conditions to form a first intermediate structure.
Step 5: as shown in fig. 9, the first intermediate structure is turned over so that the first substrate 1000 is stacked over the second substrate 2000, and the first substrate 1000 is thinned.
Step 6: as shown in fig. 10, a patterned photoresist is formed on the second surface of the thinned first substrate 1000, the first substrate 1000 is etched using the patterned photoresist as a mask, a first via 1010 is formed in the first substrate 1000, and the piezoelectric layer 1200 is exposed in the first via 1010. The height of the first via 1010 may be set to be less than or equal to the height required for the subsequent acoustic wave reflection region constituting the thin film bulk acoustic resonator.
In a variant embodiment, the first substrate 1000 may be removed entirely in step 5. Thereby omitting step 6.
Step 7: as shown in fig. 11, the piezoelectric layer 1200 at the second portion 5020 corresponding to the first electrode lead-out electrode is etched, and a second through hole 1210 is formed in the piezoelectric layer 1200 to expose the second portion 5020 of the first electrode lead-out electrode, and the first through hole 1010 and the second through hole 1210 are formed as first through holes.
Step 8: as shown in fig. 12, a first electrode material layer is deposited, which is patterned to form a first electrode 1100 of the thin film bulk acoustic resonator in a first via hole at a first region of the first substrate 1000 and a first portion 5010 of a first electrode extraction electrode in a through hole formed by the first via hole and a second via hole at a second region of the first substrate 1000. The materials for the first electrode 1100 and the first portion 5010 of the first electrode lead-out electrode are selected as described above, and will not be described here again.
Step 9: as shown in fig. 13, a first support layer material is deposited to form a first support layer 3100. The material of the first support layer is selected as described above, and will not be described in detail herein. The first support layer 3100 is patterned, and third through holes 3110 are formed in the corresponding first support layer 3100 at the first region of the first substrate 1000, forming a second intermediate structure.
Step 10: as shown in fig. 14, a third substrate 3000 is stacked on the first support layer 3100, and the third substrate 3000 is bonded to the second intermediate structure through the first support layer 3100 using a bonding process. The height of the third via 3110 sealed by the third substrate 3000 and the height of the first via 1010 after filling the first electrode 1100 together constitute the acoustic wave reflection region of the thin film bulk acoustic resonator, forming a third intermediate structure.
In another modification, as shown in fig. 15, a groove may be etched at the surface of the first region of the third substrate 3000 opposite to the first substrate 1000, and the sound wave reflection region of the thin film bulk acoustic resonator may be collectively formed by the height of the groove, the height of the third through hole 3110, and the height of the first through hole 1010 after filling the first electrode 1100.
Step 11: as shown in fig. 16, the third intermediate structure is inverted, and the second substrate 2000 is removed by a chemical or thermal process or the like debonding process using the characteristics of the first bonding material layer 2100. And then testing the frequency of the film bulk acoustic resonator, and trimming the frequency of the film bulk acoustic resonator if necessary, thereby obtaining a fourth intermediate structure.
Step 12: as shown in fig. 17, a second support layer material is deposited over the fourth intermediate structure to form a second support layer 4100. The choice of the material of the second support layer is as described above and will not be described here again. The second support layer 4100 is patterned, and fourth vias 4110 are formed in the corresponding second support layer 4100 at the first region of the third substrate 3000. A fifth via 4120 is formed in the second support layer 4100 corresponding to the second region of the third substrate 3000, the fifth via exposing the second portion 5020 of the first electrode lead-out electrode, resulting in a fifth intermediate structure.
Step 13: as shown in fig. 18, a capping layer 4000 is disposed on the second support layer 4100, and the material of the capping layer 4000 is selected as described above and will not be described herein. The capping layer 4000 material is bonded to the fifth intermediate structure through the second support layer 4100 using a bonding process. The cap layer 4000 is patterned, and a sixth via 4010 is formed in the cap layer 4000 corresponding to the fifth via 4120. The fifth through hole 4120 and the sixth through hole 4010 constitute a second through hole.
Step 14: as shown in fig. 2, the first metal layer and the third metal layer required for sequential electroplating or the first metal layer, the second metal layer and the third metal layer required for sequential electroplating are sequentially electroplated with the patterned capping layer 4000 as a mask. Then, a reflow process is performed, and after reflow, a conductive pillar 5030 is formed in the second through hole, a bump 5040 is formed on the conductive pillar 5030, or a conductive pillar 5030 is formed in the through hole, and a spacer layer and a bump 5040 are formed on the conductive pillar 5030. The materials of the conductive pillars 5030, the bumps 5040, and the spacer layer are as described above, and will not be described here.
Third embodiment
The third embodiment is a method of making the second alternative embodiment provided by the present disclosure. This is explained below with reference to fig. 3, 6 to 18, and fig. 19 to 20.
Specifically, the third embodiment is the same as steps 1 to 11 of the second embodiment.
Step 12-1: as shown in fig. 19, a second support layer 4100 material is deposited to form a second support layer 4100. The material of the second support layer 4100 is selected as described above, and will not be described here again. The second support layer 4100 is patterned, and fourth vias 4110 are formed in the corresponding second support layer 4100 at a first region of the first substrate 1000. The fifth through holes 4120 are not formed in the corresponding second support layer 4100 at the second region of the first substrate 1000.
Step 13-1: as shown in fig. 20, a capping layer 4000 is disposed on the second support layer 4100, and the material of the capping layer 4000 is selected as described above and will not be described herein. The capping layer 4000 material is bonded to the second support layer 4100 using a bonding process.
Step 14-1: as shown in fig. 3, the third substrate 3000 and the first support layer 3100 are etched to form fifth through holes in the third substrate 3000 and the first support layer 3100 at positions corresponding to the second through holes 1210, exposing the first portions 5010 of the first electrode lead-out electrodes.
Step 15-1: as shown in fig. 3, the first metal layer and the third metal layer required for the sequential plating or the first metal layer, the second metal layer and the third metal layer required for the sequential plating. Then, a reflow process is performed, and after reflow, the conductive pillars 5030 are formed in the fifth via holes, the bumps 5040 are formed on the conductive pillars 5030, or the conductive pillars 5030 are formed in the through holes, and the spacer layers and the bumps 5040 are formed on the conductive pillars 5030. The materials of the conductive pillars 5030, the bumps 5040, and the spacer layer are as described above, and will not be described here.
Fourth embodiment
A fourth embodiment is a method of making the third alternative embodiment provided by the present disclosure. This will be described below with reference to fig. 4, 6 to 18, and fig. 21.
The fourth embodiment is different from the second or third embodiment only in step 11, and the remaining steps are the same, and will not be described here again.
Specifically, in this embodiment, referring to fig. 21, after trimming the frequency of the thin film bulk acoustic resonator if necessary in step 11, the structural functional layer on the first region of the first support layer 3100 is etched, so that a through hole is formed in the structural functional layer for balancing the pressure between the subsequent first cavity and the second cavity.
Fifth embodiment
The fourth embodiment is a method of making the fourth alternative embodiment provided by the present disclosure. This is described below with reference to fig. 5, 6 to 18, and fig. 22.
Specifically, the fifth embodiment differs from the first and fourth embodiments in the processing steps that are further provided after step 12 and before step 13. The third embodiment is different in that a treatment step is further provided after step 12-1 and before step 13-1. The remaining steps are the same and are not described in detail herein.
Specifically, a trench is formed at a dicing channel between dies including adjacent thin film bulk acoustic resonators. And then depositing passivation layers on the side walls and the bottom of the grooves.
Taking the example after step 12 in the first and fourth embodiments is completed, as shown in fig. 22, the fifth intermediate structure is etched, a trench 6000 is formed at the dicing between the die including the thin film bulk acoustic resonator, and the trench 6000 forms a structure penetrating the second support layer 4100 to the first support layer 3100 and into part of the third substrate 3000. A passivation layer 6100 is then deposited over the sidewalls and bottom of the trench 6000.
The design of the new manufacturing method of the filter has the following advantages:
firstly, the steps of depositing the sacrificial material and releasing the cavity are not needed to be executed, so that the manufacturing difficulty of the planar film process is reduced, the possibility of unclean release of the cavity material is reduced, and the process flow is simplified.
Secondly, the piezoelectric layer is deposited on the flat substrate, so that the growth and the reliability of the piezoelectric layer are facilitated, and cracks of the piezoelectric layer are avoided.
The filter disclosed in the present disclosure can prepare a radio frequency device such as a duplexer and a multiplexer, and further can use the radio frequency device in the field of electronic devices such as a mobile phone, a personal digital assistant (Personal Digital Assistant, PDA), a personal wearable device, an electronic game device, and the like.
The present disclosure has been described in connection with specific embodiments, but it should be apparent to those skilled in the art that the description is intended to be illustrative and not limiting of the scope of the disclosure. Various modifications and alterations of this disclosure may be made by those skilled in the art in light of the spirit and principles of this disclosure, and such modifications and alterations are also within the scope of this disclosure.

Claims (14)

1. A method of fabricating a thin film bulk acoustic resonator, comprising:
providing a first substrate, forming a piezoelectric layer on a first surface of the first substrate, and forming a second electrode on the piezoelectric layer;
thinning the first substrate, patterning the second surface of the thinned first substrate, and forming a first through hole exposing the piezoelectric layer in the first substrate;
forming a first electrode in a first through hole of a first region of the first substrate, wherein the first electrode, the piezoelectric layer and the second electrode form a structural functional layer;
forming a first support layer on a second surface of the first substrate, patterning the first support layer, and forming a third via hole in the first support layer corresponding to the first region of the first substrate;
a third substrate is bonded on the patterned first support layer.
2. The method for manufacturing a thin film bulk acoustic resonator according to claim 1, wherein: the surface of the first region of the third substrate opposite the second surface of the first substrate is etched to form a recess.
3. The method for manufacturing a thin film bulk acoustic resonator according to claim 1 or 2, characterized in that: and forming a second support layer, patterning the second support layer, forming a fourth through hole in the second support layer corresponding to the first region of the third substrate, and forming a capping layer on the patterned second support layer.
4. A method of making a thin film bulk acoustic resonator as claimed in claim 3, wherein: forming a second portion of the first electrode lead-out electrode simultaneously with the forming of the second electrode; etching the piezoelectric layer after forming the first through hole and before depositing the first electrode material layer, forming a second through hole in the piezoelectric layer, exposing a second part of the first electrode extraction electrode in the second through hole, and forming the second through hole and the first through hole of the second area of the first substrate into a first through hole; and forming a first portion of the first electrode lead-out electrode in the first through hole while forming the first electrode.
5. The method for manufacturing a thin film bulk acoustic resonator according to claim 4, wherein: in the step of patterning the second support layer, a fifth via hole is formed in the second support layer corresponding to the second region of the third substrate while forming the fourth via hole, the fifth via hole exposing the second portion of the first electrode lead-out electrode; forming a sixth through hole in the capping layer corresponding to the fifth through hole, the fifth through hole and the sixth through hole forming a second through hole; conductive pillars are formed in the second through holes, bumps are formed on the conductive pillars or conductive pillars are formed in the second through holes, and spacers and bumps are formed on the conductive pillars.
6. A method of making a thin film bulk acoustic resonator as claimed in claims 1 to 5, wherein: the step of thinning the first substrate includes coating a first layer of bonding material, providing a second substrate, and temporarily bonding a first surface of the second substrate opposite the first surface of the first substrate.
7. The method of manufacturing a thin film bulk acoustic resonator according to claim 6, wherein: and after bonding the third substrate on the patterned first supporting layer, removing the second substrate through a de-bonding process.
8. The method of manufacturing a thin film bulk acoustic resonator as claimed in claim 1, wherein: the step of thinning the first substrate includes removing the first substrate entirely.
9. The method for manufacturing a thin film bulk acoustic resonator according to claim 4, wherein: etching the third substrate and the first support layer to form a fifth through hole in the third substrate and the first support layer at a position corresponding to the second through hole to expose a first portion of the first electrode lead-out electrode; conductive pillars are formed in the fifth through holes, bumps are formed on the conductive pillars or conductive pillars are formed in the fifth through holes, and spacers and bumps are formed on the conductive pillars.
10. A method of manufacturing a thin film bulk acoustic resonator as claimed in any one of claims 1 to 9, wherein: and etching the structural functional layer on the first region of the first supporting layer, and forming a through hole in the structural functional layer.
11. The method of manufacturing a thin film bulk acoustic resonator according to claim 10, wherein: trenches are formed at the scribe lines between the dies of adjacent thin film bulk acoustic resonators and passivation layers are deposited on the sidewalls and bottom of the trenches.
12. The method of manufacturing a thin film bulk acoustic resonator according to claim 11, wherein: the width of the trench is between the dicing blade width and the dicing street width, and the depth of the trench into the third substrate is 0.1 μm-100 μm.
13. A thin film bulk acoustic resonator, characterized by: the thin film bulk acoustic resonator is manufactured by the manufacturing method of any one of claims 1 to 12.
14. An electronic device, characterized in that: the electronic device comprising the thin film bulk acoustic resonator of claim 13.
CN202311611746.1A 2023-11-29 2023-11-29 Film bulk acoustic resonator, electronic equipment and manufacturing method thereof Pending CN117595823A (en)

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Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN202311611746.1A CN117595823A (en) 2023-11-29 2023-11-29 Film bulk acoustic resonator, electronic equipment and manufacturing method thereof

Publications (1)

Publication Number Publication Date
CN117595823A true CN117595823A (en) 2024-02-23

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Country Link
CN (1) CN117595823A (en)

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