WO2022252178A1 - 鳍片结构扬声器及其形成方法 - Google Patents

鳍片结构扬声器及其形成方法 Download PDF

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Publication number
WO2022252178A1
WO2022252178A1 PCT/CN2021/098112 CN2021098112W WO2022252178A1 WO 2022252178 A1 WO2022252178 A1 WO 2022252178A1 CN 2021098112 W CN2021098112 W CN 2021098112W WO 2022252178 A1 WO2022252178 A1 WO 2022252178A1
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Prior art keywords
fin
piezoelectric layer
fin structure
speaker
loudspeaker according
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French (fr)
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张孟伦
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Tianjin University
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Tianjin University
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    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; ELECTRIC HEARING AIDS; PUBLIC ADDRESS SYSTEMS
    • H04R17/00—Piezoelectric transducers; Electrostrictive transducers
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; ELECTRIC HEARING AIDS; PUBLIC ADDRESS SYSTEMS
    • H04R19/00—Electrostatic transducers
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; ELECTRIC HEARING AIDS; PUBLIC ADDRESS SYSTEMS
    • H04R19/00—Electrostatic transducers
    • H04R19/02—Loudspeakers
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; ELECTRIC HEARING AIDS; PUBLIC ADDRESS SYSTEMS
    • H04R31/00—Apparatus or processes specially adapted for the manufacture of transducers or diaphragms therefor

Definitions

  • the invention relates to the technical field of MEMS (micro-electro-mechanical systems), in particular to a fin-structure loudspeaker and a forming method thereof.
  • MEMS micro-electro-mechanical systems
  • the fin structure loudspeaker has the basic components as shown in Figure 1A, where C1 is the upper package cover structure, C2 is the lower package cover structure, and D1 is the core working area. Further, the top view structure of D1 is shown in FIG. 1B , the D1 structure includes a surrounding frame and several fins F1 to F8 (the number is 8 is just an example) located in the frame.
  • the thickness of the piezoelectric layer is uniform. Assuming that the driving voltage remains unchanged, when the thickness of the piezoelectric layer is thicker, the electric field inside the piezoelectric layer is smaller, the fin displacement is smaller, and the sound pressure generated by the speaker is lower, which cannot meet the index requirements; when the thickness of the piezoelectric layer is thinner At this time, although the electric field inside the piezoelectric layer is relatively large, the output linearity of the speaker is poor due to the nonlinearity of the piezoelectric material. In addition, when the thickness of the piezoelectric layer is uniform, the Q value of the fins at mechanical resonance is high, resulting in poor frequency response and small bandwidth of the speaker.
  • the present invention proposes a fin structure loudspeaker structure and a forming method thereof.
  • the first aspect of the present invention proposes a fin structure loudspeaker, including a surrounding frame and a plurality of sound-speaking fins located in the surrounding frame, and the sound-speaking fins include: a fin base; A piezoelectric layer of uneven thickness on the surface of the two vertical sidewalls.
  • the material of the fin base is silicon.
  • crystal phases of the piezoelectric layers on the surfaces of the two vertical sidewalls of the same fin base are opposite.
  • the section of the piezoelectric layer is wedge-shaped.
  • the piezoelectric layer has a maximum width at a position closest to the top and bottom of the speaker fin, and the piezoelectric layer has a minimum width at a position closest to the middle of the speaker fin;
  • the piezoelectric layer has the largest width at a position closest to one of the top and bottom ends of the sounding fin, and the piezoelectric layer has the largest width at a position closest to the top and bottom of the sounding fin. The position of the other of the two ends has the minimum width.
  • the angle between the outer surface of the piezoelectric layer and the vertical side wall surface of the fin base is defined as a first angle, and the first angle ranges from 0 to 45°.
  • the ratio of the length of the piezoelectric layer covering the vertical sidewall of the fin base to the full length of the vertical sidewall of the fin base is defined as the piezoelectric layer coverage ratio, and the piezoelectric layer covers The ratio of the ratio ranges from 10% to 100%, or from 30% to 60%.
  • the speaker fins further include: external electrodes located on the surface of the piezoelectric layer.
  • an angle between the outer surface of the external electrode and the outer surface of the piezoelectric layer is defined as a second included angle, and the value of the second included angle ranges from 0 to 45°.
  • the thickness of the piezoelectric layer under the ends of the external electrodes is greater than 100 nanometers.
  • the coverage area of the external electrode is smaller than the coverage area of the piezoelectric layer.
  • the speaker fin further includes: an internal electrode located between the fin base and the piezoelectric layer.
  • the piezoelectric layers on both sides of the same speaker fin are powered independently.
  • the piezoelectric layer material is: aluminum nitride, PZT, zinc oxide or a doped material of the above materials.
  • the piezoelectric layer is in the form of a thin film with an average thickness of 0.1 microns to 10 microns.
  • it also includes: an upper package cover structure located above the surrounding frame and the plurality of sound-speaking fins, and a lower package cover structure located below the surrounding frame and the plurality of sound-speaking fins, wherein , the upper package cover structure and/or the lower package cover structure has an acoustic hole.
  • the second aspect of the present invention provides a method for forming a fin structure loudspeaker, including: processing a wafer into a surrounding frame and a plurality of fin bases located in the surrounding frame; A piezoelectric layer with non-uniform thickness is formed on the surface of the wall, and the fin base and the piezoelectric layer constitute a sound-speaking fin.
  • the material of the fin base is silicon.
  • crystal phases of the piezoelectric layers on the surfaces of the two vertical sidewalls of the same fin base are opposite.
  • the section of the piezoelectric layer is wedge-shaped.
  • the piezoelectric layer has a maximum width at a position closest to the top and bottom of the speaker fin, and the piezoelectric layer has a minimum width at a position closest to the middle of the speaker fin;
  • the piezoelectric layer has the largest width at a position closest to one of the top and bottom ends of the sounding fin, and the piezoelectric layer has the largest width at a position closest to the top and bottom of the sounding fin. The position of the other of the two ends has the minimum width.
  • the angle between the outer surface of the piezoelectric layer and the vertical side wall surface of the fin base is defined as a first angle, and the first angle ranges from 0 to 45°.
  • the ratio of the length of the piezoelectric layer covering the vertical sidewall of the fin base to the full length of the vertical sidewall of the fin base is defined as the piezoelectric layer coverage ratio, and the piezoelectric layer covers The ratio of the ratio ranges from 10% to 100%, or from 30% to 60%.
  • the method further includes: forming external electrodes on the surface of the piezoelectric layer.
  • an angle between the outer surface of the external electrode and the outer surface of the piezoelectric layer is defined as a second included angle, and the value of the second included angle ranges from 0 to 45°.
  • the thickness of the piezoelectric layer under the ends of the external electrodes is greater than 100 nanometers.
  • the coverage area of the external electrode is smaller than the coverage area of the piezoelectric layer.
  • the method further includes: forming an internal electrode between the fin base and the piezoelectric layer.
  • the piezoelectric layers on both sides of the sound-speaking fins are powered independently.
  • the piezoelectric layer material is: aluminum nitride, PZT, zinc oxide or a doped material of the above materials.
  • the piezoelectric layer is in the form of a thin film with an average thickness of 0.1 microns to 10 microns.
  • the thickness of the piezoelectric layer material of the vertical side wall of each fin structure of the fin speaker changes along the direction of the vertical side wall of the fin (for example, it is wedge-shaped), and the specific thickness variation trend is close to the vertical side wall of the fin.
  • the sound fins are thicker at the ends and thinner near the middle of the sound fins.
  • the thickness of the piezoelectric layer changes along the extending direction of the vertical side wall of the fin structure, the characteristics of large displacement and high linearity of displacement of the fin can be satisfied at the same time.
  • the thickness of the piezoelectric layer varies along the vertical sidewall direction of the fin structure, the fin structure resonates in a wide frequency range, which can reduce the Q value and increase the bandwidth, thereby improving the frequency response of the speaker.
  • FIG. 1A and 1B are schematic diagrams of the overall structure of a fin structure speaker
  • FIGS. 2A to 2L are schematic diagrams of the forming process of the fin structure loudspeaker according to the embodiment of the present invention.
  • FIG. 3 is a cross-sectional view of a single fin base according to an embodiment of the present invention.
  • FIG. 4 is a partially enlarged view of the R1 region in FIG. 3 .
  • the overall structure of the fin structure loudspeaker according to the embodiment of the present invention is also shown in FIG. 1A and FIG. 1B , but the thickness of the piezoelectric layer in the fin base is non-uniform.
  • the processing flow of the fin structure loudspeaker according to the embodiment of the present invention will be introduced in detail below to illustrate the key features involved in the present invention.
  • the cross-section is the S1 plane in FIG. 1A , and the number of sound-speaking fins is intentionally reduced for the sake of illustration.
  • Step 1 Process the wafer into a surrounding frame and several fin bases located in the surrounding frame.
  • the masks M1 and M2 are respectively covered on both sides of the wafer D1 by CVD or other processes.
  • the material can be silicon dioxide, silicon nitride, aluminum nitride, etc., or a composite layer of the above materials.
  • ordinary silicon wafers are used instead of SOI silicon wafers, which can greatly reduce manufacturing costs.
  • one side of the mask is patterned by dry or wet etching, and the patterned mask layer is M1 in this example.
  • the number of fin bases is reduced to 3 pieces, and accordingly, 4 exposure windows are set on the cross section of the mask M1.
  • three fin bases are processed on D1 by wet process (potassium hydroxide solution etching, etc.) or dry process (DRIE, etc.).
  • the processed fin gap between the fin bases runs through the wafer D1 and ends at the mask layer M2.
  • Step 2 forming a piezoelectric layer with an uneven thickness on the surfaces of the two vertical side walls of the fin base, and the fin base and the piezoelectric layer form a speaker fin.
  • the vertical sidewall is the sidewall of the fin perpendicular to the base.
  • the piezoelectric layer film L1 is deposited on one side of the wafer D1, wherein the section of L1 located on the vertical side wall of the fin has a wedge shape or similar wedge shape, specifically, the wedge is near the wafer
  • the portion of the surface of D1 has a large width and gradually becomes thinner as the depth increases.
  • a layer of protective layer material P1 may be bonded to the non-deposition side of D1 for protecting the cavity and devices during the deposition process.
  • a piezoelectric layer L2 is deposited on the opposite side of the deposited layer L1 (optionally, a protective layer P2 is used).
  • L2 and L1 have the same or similar cross-sectional structure and size distribution.
  • the piezoelectric layer thickness varies with depth.
  • the piezoelectric layer material includes aluminum nitride, PZT, zinc oxide, and doped materials of the above materials; the piezoelectric layer is in the form of a thin film with an average thickness of 0.1 micron to 10 micron.
  • the crystal phases of the piezoelectric layers on the surfaces of the two vertical sidewalls of the same fin base are opposite. This is beneficial to the stress symmetry of the piezoelectric layer on both sides of the same fin base.
  • a step may further be included: forming an internal electrode located between the fin base and the piezoelectric layer.
  • the internal electrodes are not an essential structure.
  • the fin base is made of a material with low resistivity, the fin base can be directly used as the internal electrode.
  • the method for forming a fin structure loudspeaker according to the embodiment of the present invention may further include a step of forming an external electrode on the surface of the piezoelectric layer.
  • the metal layer E2 is continuously deposited on the side where L2 has been deposited as an electrode.
  • E2 has a wedge-shaped structure on the vertical sidewall of the piezoelectric layer.
  • FIG. 2H continue to deposit a metal layer E1 as an external electrode (optionally, use a protective layer P3 ) on the opposite side where the E2 layer has been deposited.
  • the external electrode E2 has a wedge-shaped structure on the vertical sidewall of the piezoelectric layer.
  • E2 and E1 have a "lap" at the end deep into the wafer to form a layer of metal electrodes.
  • the method for forming a fin structure loudspeaker according to the embodiment of the present invention may further include a step of: forming breaks in the external electrodes at both ends of the sound-speaking fins.
  • the external electrodes that originally surround the piezoelectric layer are disconnected above the top end and the bottom end of each fin base through a process such as dry or wet etching, This enables independent power supply to the piezoelectric layers located on the two vertical sidewalls of each fin.
  • the metal located on the upper and lower surfaces of the D1 frame can also be removed for subsequent processes.
  • the method for forming the fin structure loudspeaker according to the embodiment of the present invention may further include a step of packaging the upper package cover structure and the lower package cover structure.
  • the upper package lid structure C1 and the lower package lid structure C2 are respectively bonded on both sides of FIG. 2I , wherein V1-2 and U1-2 are acoustic holes located on C1 and C2.
  • This step is a common process and is not the focus of this article, so specific steps are omitted.
  • an "overlap" is formed between the piezoelectric layers L1 and L2/between the electrodes E1 and E2 deep in the wafer D1.
  • the above-mentioned electrodes and piezoelectric layers can also be formed on the vertical side walls.
  • the non-contact structure as shown in FIG. 2K , on the two vertical sidewalls of each fin, there is an exposed wafer surface between the piezoelectric layers L1 and L2 / between the electrodes E1 and E2 .
  • only one side of the fin may cover the piezoelectric layer L1 and the electrode E1 .
  • the wedge-shaped piezoelectric layer and external electrodes can be defined in shape and size.
  • the angle between the outer surface of the piezoelectric layer and the side plane of the fin base is defined as a first angle ⁇ , and the value range of the first angle ⁇ is 0 to 45°.
  • the angle between the outer surface of the external electrode and the outer surface of the piezoelectric layer is defined as a second angle ⁇ , and the value range of the second angle ⁇ is 0 to 45°.
  • the value of the covering height (length) h2 of the piezoelectric layer L1 on one side of the vertical sidewall is between 10% and 100% of H, preferably 30%. to 60%.
  • the coverage area of the external electrode is smaller than the coverage area of the piezoelectric layer (so as to ensure that the external electrode will not cover the surface of the silicon-based fin), in other words, the external electrode in Figure 3
  • the dimension h1' is smaller than the dimension h2' of the piezoelectric layer
  • the dimension h1 of the external electrode is smaller than the dimension h2 of the piezoelectric layer.
  • the thickness D1 of the piezoelectric layer below the end of the external electrode is required to be greater than 100nm, so as to ensure that there is a sufficiently thick piezoelectric material between the electrode E1 and the silicon-based fin Fn Thereby achieving an insulating effect and preventing the piezoelectric layer from being electrically broken down.
  • internal electrodes may also be provided between the piezoelectric layer and the fin base for better electrical connection.
  • the resistivity of the material of the fin base is not required.

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  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Acoustics & Sound (AREA)
  • Signal Processing (AREA)
  • Manufacturing & Machinery (AREA)
  • Piezo-Electric Transducers For Audible Bands (AREA)

Abstract

本发明公开了一种鳍片结构扬声器及其形成方法。该鳍片结构扬声器包括周围框架和位于周围框架内的多个扬声鳍片，扬声鳍片包括：鳍片基底；位于鳍片基底的两个垂直侧壁的表面、厚度不均匀的压电层。根据本发明的技术方案，鳍片扬声器的每个鳍片结构的垂直侧壁的压电层材料的厚度沿鳍片垂直侧壁方向变化(例如呈尖劈形)，具体厚度变化趋势为靠近扬声鳍片的端部位置厚度更厚，靠近扬声鳍片的中部位置厚度更薄。这样，当压电层厚度沿鳍片结构的垂直侧壁延伸方向变化时，可以同时满足鳍片位移大和位移线性度高的特点。另一方面，由于压电层厚度沿鳍片结构垂直侧壁方向变化，鳍片结构在宽频内谐振可降低Q值提高带宽，进而改善扬声器的频率响应。

Description

鳍片结构扬声器及其形成方法 技术领域
本发明涉及MEMS(微机电系统)技术领域，具体涉及一种鳍片结构扬声器及其形成方法。
背景技术
近年来，MEMS(微机电系统)技术领域取得了飞速的发展，微型的鳍片结构扬声器已经面世。鳍片结构扬声器具有如图1A所示的基本部分组成，其中C1为上封装盖结构，C2为下封装盖结构，D1为核心工作区域。进一步D1的俯视结构如图1B所示，D1结构包含周围框架和位于框架内的若干鳍片F1至F8(数量为8仅是示例)。
现有技术的鳍片结构扬声器中，压电层厚度是均匀的。假设驱动电压保持不变，当压电层厚度较厚时压电层内部的电场较小，鳍片位移较小，扬声器产生的声压较低，无法满足指标要求；当压电层厚度较薄时，虽然压电层内部的电场较大，由于压电材料的非线性，导致扬声器输出线性度较差。另外，当压电层厚度均匀时，鳍片在机械谐振时Q值较高，导致扬声器的频率响应变差，带宽较小。
发明内容
有鉴于此，本发明提出一种鳍片结构扬声器结构及其形成方法。
本发明第一方面提出一种鳍片结构扬声器，包括周围框架和位于所述周围框架内的多个扬声鳍片，所述扬声鳍片包括：鳍片基底；位于所述鳍片基底的两个垂直侧壁的表面、厚度不均匀的压电层。
可选地，所述鳍片基底的材料为硅。
可选地，同一个所述鳍片基底的两个垂直侧壁的表面的压电层的晶相相反。
可选地，所述压电层的断面呈尖劈形。
可选地，所述压电层在最靠近所述扬声鳍片的顶端和底端的位置具有最大宽度，所述压电层在最靠近所述扬声鳍片的中间的位置具有最小宽度；或者，所述压电层在最靠近所述扬声鳍片的顶端和底端两者中其一的位置具有最大宽度，所述压电层在最靠近所述扬声鳍片的顶端和底端两者中另一的位置具有最小宽度。
可选地，定义所述压电层的外侧表面与所述鳍片基底的垂直侧壁表面的夹角为第一夹角，所述第一夹角度取值范围为0至45°。
可选地，定义所述压电层覆盖所述鳍片基底的垂直侧壁的长度与所述鳍片基底的垂直侧壁的全长度的比例为压电层覆盖比例，所述压电层覆盖比例的比取值范围为10％至100％，或者30％至60％。
可选地，所述扬声鳍片还包括：位于所述压电层的表面的外电极。
可选地，定义所述外电极的外侧表面与所述压电层的外侧表面的夹角为第二夹角，所述第二夹角度取值范围为0至45°。
可选地，所述外电极的末端下方的压电层的厚度大于100纳米。
可选地，所述外电极覆盖区域小于所述压电层覆盖区域。
可选地，所述扬声鳍片还包括：位于所述鳍片基底与所述压电层之间的内电极。
可选地，同一个所述扬声鳍片两侧的压电层独立供电。
可选地，所述压电层材料为：氮化铝、PZT、氧化锌或者上述材料的掺杂材料。
可选地，所述压电层为薄膜形式，平均厚度为0.1微米至10微米。
可选地，还包括：位于所述周围框架和所述多个扬声鳍片的上方的上封装盖结构以及位于周围框架和所述多个扬声鳍片的下方的下封装盖结构，其中，所述上封装盖结构和/或下封装盖结构具有声学孔。
本发明第二方面提出一种鳍片结构扬声器的形成方法，包括：将晶圆加工成周围框架和位于所述周围框架内的多个鳍片基底；在所述鳍片基底的两个垂直侧壁的表面形成厚度不均匀的压电层，所述鳍片基底和所述压电层组成扬声鳍片。
可选地，所述鳍片基底的材料为硅。
可选地，同一个所述鳍片基底的两个垂直侧壁的表面的压电层的晶相相反。
可选地，所述压电层的断面呈尖劈形。
可选地，所述压电层在最靠近所述扬声鳍片的顶端和底端的位置具有最大宽度，所述压电层在最靠近所述扬声鳍片的中间的位置具有最小宽度；或者，所述压电层在最靠近所述扬声鳍片的顶端和底端两者中其一的位置具有最大宽度，所述压电层在最靠近所述扬声鳍片的顶端和底端两者中另一的位置具有最小宽度。
可选地，定义所述压电层的外侧表面与所述鳍片基底的垂直侧壁表面的夹角为第一夹角，所述第一夹角度取值范围为0至45°。
可选地，定义所述压电层覆盖所述鳍片基底的垂直侧壁的长度与所述鳍片基底的垂直侧壁的全长度的比例为压电层覆盖比例，所述压电层覆盖比例的比取值范围为10％至100％，或者30％至60％。
可选地，还包括：在所述压电层的表面形成外电极。
可选地，定义所述外电极的外侧表面与所述压电层的外侧表面的夹角为第二夹角，所述第二夹角度取值范围为0至45°。
可选地，所述外电极的末端下方的压电层的厚度大于100纳米。
可选地，所述外电极覆盖区域小于所述压电层覆盖区域。
可选地，还包括：在所述鳍片基底与所述压电层之间形成内电极。
可选地，所述扬声鳍片两侧的压电层独立供电。
可选地，所述压电层材料为：氮化铝、PZT、氧化锌或者上述材料的掺杂材料。
可选地，所述压电层为薄膜形式，平均厚度为0.1微米至10微米。
可选地，还包括：在所述周围框架和所述多个扬声鳍片的上方封装上封装盖结构以及在所述周围框架和所述多个扬声鳍片的下方封装下封装盖结构，其中，所述上封装盖结构和/或下封装盖结构具有声学孔。
根据本发明的技术方案，鳍片扬声器的每个鳍片结构的垂直侧壁的压 电层材料的厚度沿鳍片垂直侧壁方向变化(例如呈尖劈形)，具体厚度变化趋势为靠近扬声鳍片的端部位置厚度更厚，靠近扬声鳍片的中部位置厚度更薄。这样，当压电层厚度沿鳍片结构的垂直侧壁延伸方向变化时，可以同时满足鳍片位移大和位移线性度高的特点。另一方面，由于压电层厚度沿鳍片结构垂直侧壁方向变化，鳍片结构在宽频内谐振可降低Q值提高带宽，进而改善扬声器的频率响应。
附图说明
为了说明而非限制的目的，现在将根据本发明的优选实施例、特别是参考附图来描述本发明，其中：
图1A与图1B为鳍片结构扬声器的总体结构示意图；
图2A至图2L为本发明实施方式的鳍片结构扬声器的形成过程示意图；
图3为本发明实施方式的单个鳍片基底的断面图；
图4为图3中R1区域的局部放大图。
具体实施方式
下面结合实施例中的附图，对本发明实施例中的技术方案进行清楚、完整地描述，显然，所描述的实施例仅仅是本发明的一部分实施例，而并不是全部的实施例。基于本发明中的实施例，本领域普通技术人员所获得的所有其他实施例，都属于本发明保护的范围。
本发明实施方式的鳍片结构扬声器的总体结构也如图1A和图1B所示，但是鳍片基底中的压电层的厚度是非均匀的。下面详细介绍本发明实施方式的鳍片结构扬声器的加工流程，来说明本发明中所涉及的关键特征。其中截面为图1A中的S1平面，同时为了便于说明，有意减少扬声鳍片的数量。
步骤一：将晶圆加工成周围框架和位于周围框架内的若干个鳍片基底。
(1)如图2A所示，在晶圆D1两侧以CVD或其他工艺方式分别覆盖掩模M1和M2，其中晶圆可采用单晶硅、石英、砷化镓等业内常见材 料，掩模材料可选二氧化硅、氮化硅、氮化铝等，或上述材料的复合层。在这里采用普通硅晶圆而非SOI硅片，可极大降低制造成本。
(2)如图2B所示，通过干法或湿法刻蚀的方式将其中一侧掩模图形化，本实例中图形化的掩模层为M1。此处为了方便展示，将鳍片基底数量降低至3片，相应地，掩膜M1的断面上设置4个暴露窗口。
(3)如图2C所示，以湿法工艺(氢氧化钾溶液刻蚀等)或干法工艺(DRIE等)在D1上加工出3个鳍片基底。其中加工出的鳍片基底之间的鳍片间隙贯穿晶圆D1，并截止于掩模层M2。
(4)如图2D所示，除去掩模M1和M2，保留具有鳍片基底的晶圆D1。此时，晶圆外围的部分变为了鳍片结构扬声器中的周围框架。
事实上，上述过程仅为获取图2D中通透的鳍片基底的一种可选方式，目的并不是用于限制。也可以使用其他工艺流程获得图2D的结构。
步骤二：在鳍片基底的两个垂直侧壁的表面形成厚度不均匀的压电层，鳍片基底和压电层组成扬声鳍片。这里的垂直侧壁为鳍片的与基底垂直的侧壁。
如图2E所示，在晶圆D1的一侧沉积压电层薄膜L1，其中L1位于鳍片垂直侧壁上的断面具有尖劈形或类似尖劈形，具体的，尖劈在靠近晶圆D1表面的部分具有较大的宽度，随着深度加深逐渐变细。此处可选的，在D1的非沉积侧可键合一层保护层材料P1，用于在沉积工艺中保护腔体和器件。然后，如图2F所示，在沉积过L1层的对侧(可选的，使用保护层P2)沉积压电层L2，优选地，L2与L1具有相同或相近的截面结构和尺寸分布。此外，在本实例中L1和L2的深入晶圆的末端存在“搭接”，从而使L1和L2融合成一层压电层。在非搭接部分，压电层厚度随深度变化。压电层材料包括氮化铝、PZT、氧化锌、以及上述材料的掺杂材料；压电层为薄膜形式，平均厚度为0.1微米至10微米。
同一个鳍片基底的两个垂直侧壁的表面的压电层的晶相相反。这样有利于同一个鳍片基底两侧的压电层应力对称。
本发明实施方式的鳍片结构扬声器的形成方法中，在步骤一与步骤二之间，还可以包括步骤：形成位于鳍片基底与压电层之间的内电极。内电极并不是必须的结构。当鳍片基底为电阻率低的材料时，可以直接以鳍片基底作为内电极。
本发明实施方式的鳍片结构扬声器的形成方法中，还可以包括步骤：在压电层的表面形成外电极。
如图2G所示，在沉积过L2的一侧继续沉积金属层E2作为电极。E2在压电层的垂直侧壁上具有尖劈形的结构。然后，如图2H所示，在沉积过E2层的对侧继续沉积金属层E1作为外电极(可选的，使用保护层P3)。外电极E2在压电层的垂直侧壁上具有尖劈形的结构，在本实例中E2和E1在深入晶圆的末端存在“搭接”从而在形成一层金属电极。
本发明实施方式的鳍片结构扬声器的形成方法中，还可以包括步骤：在所述扬声鳍片的两端位置的所述外电极中形成断口。
具体地，如图2I所示，通过干法或湿法刻蚀等工艺，将原本包围住压电层的外电极在每个鳍片基底的顶端位置之上和底端位置之上断开，从而实现对位于每个鳍片两个垂直侧壁上压电层的独立供电。可选的也可以将位于D1框架上下表面的金属移除，以便进行后续工艺。
本发明实施方式的鳍片结构扬声器的形成方法中，还可以包括步骤：封装上封装盖结构与下封装盖结构。
具体地，如图2J所示，在图2I的两侧分别键合上封装盖结构C1和下封装盖结构C2，其中V1-2和U1-2是位于C1和C2上的声学孔。此步骤为常用工艺且不是本文重点因此具体步骤省略。
作为举例，前述结构工艺中压电层L1与L2之间/电极E1与E2之间在晶圆D1深处形成“搭接”，此外，上述电极和压电层也可以在垂直侧壁上形成非接触结构，如图2K所示，在每个鳍片的两个垂直侧壁上，压电层L1与L2之间/电极E1与E2之间均留有裸露的晶圆表面。
在本发明其他实施方式的鳍片结构扬声器的形成方法中，也可如图2L所示实例，仅在鳍片的单侧覆盖压电层L1和电极E1。
如图3所示，可对尖劈型的压电层和外电极加以形状和尺寸限定。定义压电层的外侧表面与鳍片基底的侧平面的夹角为第一夹角α，第一夹角度α取值范围为0至45°。定义外电极的外侧表面与压电层的外侧表面的夹角为第二夹角β，第二夹角度β取值范围为0至45°。对于垂直侧壁高度(长度)为H的鳍片基底，其垂直侧壁的单侧的压电层L1的覆盖高度(长度)h2的数值为H的10％到100％之间，优选30％到60％。此要求在覆盖压电层的情况下同样适用于另一侧压电层。另外，外电极末端和压电层末端的相对位置基本原则为：外电极覆盖区域小于压电层覆盖区域(从而确保外电极不会覆盖到硅基鳍片的表面)，换言之，图3中外电极尺寸h1’小于压电层尺寸h2’，外电极尺寸h1小于压电层尺寸h2。
如图4所示(图4为图3中R1放大区域)，要求外电极末端下方的压电层厚度D1大于100nm，这样确保电极E1与硅基鳍片Fn之间有足够厚的压电材料从而达到绝缘效果，防止压电层被电学击穿。
在本发明其他实施方式的鳍片结构扬声器中，压电层和鳍片基底之间也可以提供内电极用于更好的电学连接。该情况下鳍片基底的材料的电阻率不做要求。
上述具体实施方式，并不构成对本发明保护范围的限制。本领域技术人员应该明白的是，取决于设计要求和其他因素，可以发生各种各样的修改、组合、子组合和替代。任何在本发明的精神和原则之内所作的修改、等同替换和改进等，均应包含在本发明保护范围之内。

Claims (32)

  1. 一种鳍片结构扬声器，其特征在于，包括周围框架和位于所述周围框架内的多个扬声鳍片，所述扬声鳍片包括：
    鳍片基底；
    位于所述鳍片基底的两个垂直侧壁的表面、厚度不均匀的压电层。
  2. 根据权利要求1所述的鳍片结构扬声器，其特征在于，所述鳍片基底的材料为硅。
  3. 根据权利要求1所述的鳍片结构扬声器，其特征在于，同一个所述鳍片基底的两个垂直侧壁的表面的压电层的晶相相反。
  4. 根据权利要求1所述的鳍片结构扬声器，其特征在于，所述压电层的断面呈尖劈形。
  5. 根据权利要求4所述的鳍片结构扬声器，其特征在于，
    所述压电层在最靠近所述扬声鳍片的顶端和底端的位置具有最大宽度，所述压电层在最靠近所述扬声鳍片的中间的位置具有最小宽度；或者，
    所述压电层在最靠近所述扬声鳍片的顶端和底端两者中其一的位置具有最大宽度，所述压电层在最靠近所述扬声鳍片的顶端和底端两者中另一的位置具有最小宽度。
  6. 根据权利要求4所述的鳍片结构扬声器，其特征在于，定义所述压电层的外侧表面与所述鳍片基底的垂直侧壁表面的夹角为第一夹角，所述第一夹角度取值范围为0至45°。
  7. 根据权利要求4所述的鳍片结构扬声器，其特征在于，定义所述压电层覆盖所述鳍片基底的垂直侧壁的长度与所述鳍片基底的垂直侧壁的全长度的比例为压电层覆盖比例，所述压电层覆盖比例的比取值范围为 10％至100％，或者30％至60％。
  8. 根据权利要求1所述的鳍片结构扬声器，其特征在于，所述扬声鳍片还包括：位于所述压电层的表面的外电极。
  9. 根据权利要求8所述的鳍片结构扬声器，其特征在于，定义所述外电极的外侧表面与所述压电层的外侧表面的夹角为第二夹角，所述第二夹角度取值范围为0至45°。
  10. 根据权利要求8所述的鳍片结构扬声器，其特征在于，所述外电极的末端下方的压电层的厚度大于100纳米。
  11. 根据权利要求8所述的鳍片结构扬声器，其特征在于，所述外电极覆盖区域小于所述压电层覆盖区域。
  12. 根据权利要求1所述的鳍片结构扬声器，其特征在于，所述扬声鳍片还包括：位于所述鳍片基底与所述压电层之间的内电极。
  13. 根据权利要求1所述的鳍片结构扬声器，其特征在于，同一个所述扬声鳍片两侧的压电层独立供电。
  14. 根据权利要求1所述的鳍片结构扬声器，其特征在于，所述压电层材料为：氮化铝、PZT、氧化锌或者上述材料的掺杂材料。
  15. 根据权利要求1所述的鳍片结构扬声器，其特征在于，所述压电层为薄膜形式，平均厚度为0.1微米至10微米。
  16. 根据权利要求1至15中任一项所述的鳍片结构扬声器，其特征在于，还包括：位于所述周围框架和所述多个扬声鳍片的上方的上封装盖结构以及位于周围框架和所述多个扬声鳍片的下方的下封装盖结构，其中， 所述上封装盖结构和/或下封装盖结构具有声学孔。
  17. 一种鳍片结构扬声器的形成方法，其特征在于，包括：
    将晶圆加工成周围框架和位于所述周围框架内的多个鳍片基底；
    在所述鳍片基底的两个垂直侧壁的表面形成厚度不均匀的压电层，所述鳍片基底和所述压电层组成扬声鳍片。
  18. 根据权利要求17所述的鳍片结构扬声器的形成方法，其特征在于，所述鳍片基底的材料为硅。
  19. 根据权利要求17所述的鳍片结构扬声器，其特征在于，同一个所述鳍片基底的两个垂直侧壁的表面的压电层的晶相相反。
  20. 根据权利要求17所述的鳍片结构扬声器的形成方法，其特征在于，所述压电层的断面呈尖劈形。
  21. 根据权利要求20所述的鳍片结构扬声器的形成方法，其特征在于，
    所述压电层在最靠近所述扬声鳍片的顶端和底端的位置具有最大宽度，所述压电层在最靠近所述扬声鳍片的中间的位置具有最小宽度；或者，
    所述压电层在最靠近所述扬声鳍片的顶端和底端两者中其一的位置具有最大宽度，所述压电层在最靠近所述扬声鳍片的顶端和底端两者中另一的位置具有最小宽度。
  22. 根据权利要求20所述的鳍片结构扬声器的形成方法，其特征在于，定义所述压电层的外侧表面与所述鳍片基底的垂直侧壁表面的夹角为第一夹角，所述第一夹角度取值范围为0至45°。
  23. 根据权利要求20所述的鳍片结构扬声器的形成方法，其特征在于，定义所述压电层覆盖所述鳍片基底的垂直侧壁的长度与所述鳍片基底 的垂直侧壁的全长度的比例为压电层覆盖比例，所述压电层覆盖比例的比取值范围为10％至100％，或者30％至60％。
  24. 根据权利要求17所述的鳍片结构扬声器的形成方法，其特征在于，还包括：在所述压电层的表面形成外电极。
  25. 根据权利要求24所述的鳍片结构扬声器的形成方法，其特征在于，定义所述外电极的外侧表面与所述压电层的外侧表面的夹角为第二夹角，所述第二夹角度取值范围为0至45°。
  26. 根据权利要求24所述的鳍片结构扬声器的形成方法，其特征在于，所述外电极的末端下方的压电层的厚度大于100纳米。
  27. 根据权利要求24所述的鳍片结构扬声器的形成方法，其特征在于，所述外电极覆盖区域小于所述压电层覆盖区域。
  28. 根据权利要求17所述的鳍片结构扬声器的形成方法，其特征在于，还包括：在所述鳍片基底与所述压电层之间形成内电极。
  29. 根据权利要求17所述的鳍片结构扬声器的形成方法，其特征在于，所述扬声鳍片两侧的压电层独立供电。
  30. 根据权利要求17所述的鳍片结构扬声器的形成方法，其特征在于，所述压电层材料为：氮化铝、PZT、氧化锌或者上述材料的掺杂材料。
  31. 根据权利要求17所述的鳍片结构扬声器的形成方法，其特征在于，所述压电层为薄膜形式，平均厚度为0.1微米至10微米。
  32. 根据权利要求17至31中任一项所述的鳍片结构扬声器的形成方法，其特征在于，还包括：在所述周围框架和所述多个扬声鳍片的上方封 装上封装盖结构以及在所述周围框架和所述多个扬声鳍片的下方封装下封装盖结构，其中，所述上封装盖结构和/或下封装盖结构具有声学孔。
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