WO2020140572A1 - Mems麦克风制造方法 - Google Patents

Mems麦克风制造方法 Download PDF

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Publication number
WO2020140572A1
WO2020140572A1 PCT/CN2019/113322 CN2019113322W WO2020140572A1 WO 2020140572 A1 WO2020140572 A1 WO 2020140572A1 CN 2019113322 W CN2019113322 W CN 2019113322W WO 2020140572 A1 WO2020140572 A1 WO 2020140572A1
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Prior art keywords
layer
diaphragm
diaphragm structure
depositing
mems microphone
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PCT/CN2019/113322
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English (en)
French (fr)
Inventor
孟珍奎
刘政谚
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瑞声声学科技(深圳)有限公司
瑞声科技(新加坡)有限公司
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Publication of WO2020140572A1 publication Critical patent/WO2020140572A1/zh

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Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; DEAF-AID SETS; PUBLIC ADDRESS SYSTEMS
    • H04R31/00—Apparatus or processes specially adapted for the manufacture of transducers or diaphragms therefor
    • H04R31/003—Apparatus or processes specially adapted for the manufacture of transducers or diaphragms therefor for diaphragms or their outer suspension
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; DEAF-AID SETS; PUBLIC ADDRESS SYSTEMS
    • H04R19/00—Electrostatic transducers
    • H04R19/005—Electrostatic transducers using semiconductor materials
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; DEAF-AID SETS; PUBLIC ADDRESS SYSTEMS
    • H04R19/00—Electrostatic transducers
    • H04R19/04—Microphones
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; DEAF-AID SETS; PUBLIC ADDRESS SYSTEMS
    • H04R31/00—Apparatus or processes specially adapted for the manufacture of transducers or diaphragms therefor
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; DEAF-AID SETS; PUBLIC ADDRESS SYSTEMS
    • H04R7/00—Diaphragms for electromechanical transducers; Cones
    • H04R7/02—Diaphragms for electromechanical transducers; Cones characterised by the construction
    • H04R7/04—Plane diaphragms
    • H04R7/06—Plane diaphragms comprising a plurality of sections or layers
    • H04R7/10—Plane diaphragms comprising a plurality of sections or layers comprising superposed layers in contact
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; DEAF-AID SETS; PUBLIC ADDRESS SYSTEMS
    • H04R2201/00—Details of transducers, loudspeakers or microphones covered by H04R1/00 but not provided for in any of its subgroups
    • H04R2201/003—Mems transducers or their use
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; DEAF-AID SETS; PUBLIC ADDRESS SYSTEMS
    • H04R2307/00—Details of diaphragms or cones for electromechanical transducers, their suspension or their manufacture covered by H04R7/00 or H04R31/003, not provided for in any of its subgroups
    • H04R2307/025—Diaphragms comprising polymeric materials
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; DEAF-AID SETS; PUBLIC ADDRESS SYSTEMS
    • H04R2499/00—Aspects covered by H04R or H04S not otherwise provided for in their subgroups
    • H04R2499/10—General applications
    • H04R2499/11—Transducers incorporated or for use in hand-held devices, e.g. mobile phones, PDA's, camera's

Definitions

  • the present invention relates to microphone technology, and in particular, to a method for manufacturing a Micro-Electro-Mechanic (MEMS) microphone.
  • MEMS Micro-Electro-Mechanic
  • MEMS microphones are widely used in current mobile phones; common MEMS microphones are capacitive, which includes a diaphragm and a back
  • the board and the two constitute a MEMS acoustic sensing capacitor, and the MEMS acoustic sensing capacitor is further connected to the processing chip through a connecting plate to output the acoustic sensing signal to the processing chip for signal processing.
  • the prior art proposes a dual-diaphragm MEMS microphone structure, that is, a two-layer diaphragm is used to form a capacitive structure with a backplane.
  • the diaphragm and the back plate of the above MEMS microphone are made on the same silicon base and using a semiconductor manufacturing process, and the manufacturing process also includes forming an acoustic cavity, a back cavity, an acoustic hole, and ventilation Process steps such as holes and connecting plates.
  • each manufacturing process step of the MEMS microphone is formed on the same silicon base, the next process step must be performed after the previous process step is completed, which will result in a lower overall manufacturing efficiency of the MEMS microphone.
  • the present invention provides a method for manufacturing a MEMS microphone that can improve the overall manufacturing efficiency of the MEMS microphone.
  • a preparation method of MEMS microphone includes the following steps:
  • the back side is etched to form the back cavity structure corresponding to the middle body region of the back plate structure.
  • the depositing the backplane material layer includes sequentially depositing a first silicon nitride layer, a second polysilicon layer, and a second silicon nitride layer.
  • the extraction electrode for preparing the first diaphragm structure, the second diaphragm structure, and the back plate structure includes:
  • the electrode layer is deposited and patterned to form a first extraction electrode of the first diaphragm structure, a second extraction electrode of the second diaphragm structure, and a third extraction electrode of the backplate structure.
  • the forming of the back cavity includes:
  • the first oxide layer corresponding to the back cavity region under the first diaphragm structure is removed.
  • a step of depositing a passivation protective layer after forming the electrode extraction hole is further included.
  • At least one through hole penetrating the first diaphragm structure, the support member, and the second diaphragm structure is further included, and the through hole communicates the back cavity with the external environment.
  • a step of forming protrusions on the upper and lower surfaces of the middle body region of the backplane structure is further included.
  • the material of the support member includes silicon nitride.
  • the material of the electrode includes Cr and Au.
  • the invention provides a method for preparing a MEMS microphone with a double diaphragm structure, which is prepared by a standard semiconductor process and is easy to integrate with other semiconductor devices.
  • FIG. 1 is a schematic structural view of a MEMS microphone according to an embodiment of the invention.
  • FIG. 2 is a schematic structural diagram of a MEMS microphone according to another embodiment of the invention.
  • FIG. 3 is a preparation flow chart of a MEMS microphone according to an embodiment of the invention.
  • 4a-4v are schematic diagrams of the manufacturing process of the MEMS microphone involved in one embodiment of the present invention.
  • the MEMS microphone structure 100 prepared by the manufacturing method proposed by the present invention includes a substrate 101 and a capacitor system 103 disposed on the substrate 101 and insulated from the substrate 101.
  • the material of the substrate 101 is preferably a semiconductor material, such as silicon, which has a back cavity 102, a first surface 101A, and a second surface 101B opposite to the first surface.
  • An insulating layer 107 is provided on the first surface 101A of the substrate 101, and the back cavity 102 penetrates the insulating layer 107 and the first and second surfaces of the base 101.
  • the back cavity 102 can be formed by bulk silicon process or dry etching.
  • the capacitance system 103 includes a backplate 105 and first and second diaphragms 104 and 106 that are opposite to the backplate 105 and disposed on both sides of the backplate 105. Between the first diaphragm 104 and the backplate 105, the second diaphragm An insulating layer 107 is provided between the film 106 and the back plate 105, and between the first diaphragm 104 and the substrate 101.
  • the central body area of the back plate 105 includes spaced-apart acoustic through holes 108. In the present invention, the central body area of the back plate 105 is, for example, the area corresponding to the back cavity 102, and outside this area is the edge area of the back plate 105 .
  • the support 109 passes through the acoustic through hole to fix the first diaphragm 104 and the second diaphragm 106 fixedly connected. Specifically, the support 109 abuts the top surface of the first diaphragm 104 and the bottom surface of the second diaphragm 106, respectively.
  • the insulating layer 107 separates the first diaphragm 104 and the back plate 105 by a certain distance and forms a first gap 110, and separates the second diaphragm 106 and the back plate 105 by a distance and forms a second gap 111.
  • the acoustic through hole 108 penetrates the first gap 110 and the second gap 111 to form an inner cavity 112.
  • the first diaphragm 104 and the back plate 105, the second diaphragm 106 and the back plate 105 will be charged with opposite polarities, thereby forming a capacitance
  • the distance between the back plate 105 and the first diaphragm 104 and the second diaphragm 106 will change, resulting in a change in the capacitance of the capacitor system, and then converting the sound wave signal into an electrical signal, Realize the corresponding function of the microphone.
  • first diaphragm 104 and the second diaphragm 106 are square, round, or oval, and at least one support 109 is provided on the bottom surface of the first diaphragm 104 and the second diaphragm 106 Between the top surfaces.
  • the supporting member 109 is provided to pass through the acoustic through-hole 108 of the back plate 105 to fixedly connect the first diaphragm 104 and the second diaphragm 106;
  • the support 109 may be formed on the top surface of the first diaphragm 104 by various preparation techniques, such as physical vapor deposition, electrochemical deposition, chemical vapor deposition, and molecular beam epitaxy.
  • the support 109 may be composed of a semiconductor material such as silicon or may include a semiconductor material such as silicon.
  • a semiconductor material such as silicon or may include a semiconductor material such as silicon.
  • It may also be composed of at least one of the following or may include at least one of the following: metal, dielectric material, piezoelectric material, piezoresistive material, and ferroelectric material. It can also be made of a dielectric material such as silicon nitride.
  • the support 109 may be integrally formed with the first diaphragm 104 and the second diaphragm 106, respectively.
  • the second diaphragm 106 of the present invention includes a plurality of release holes 113, and a dielectric material 114 is used to close the release holes 113.
  • the first electrode 104, the second electrode 106, and the lead-out electrodes of the back plate 105 are also included, respectively, the first electrode 115, the second electrode 116, and the third electrode 117, respectively.
  • a surface passivation protection layer 118 is also included.
  • the second diaphragm 106 also includes a through hole 119 penetrating the first diaphragm 104, the support member 109, and the second diaphragm 106.
  • the through hole 119 is provided at the center of the first diaphragm 104 and the second diaphragm 106, for example.
  • the back cavity 102 and the external environment make the external pressure of the first diaphragm 104 and the second diaphragm 106 consistent.
  • FIGS. 3-4 it is a flowchart of an embodiment of a method for manufacturing a MEMS microphone provided by the present invention.
  • the manufacturing method is used to manufacture the microphone 100 shown in FIG. 1 or FIG. 2, and specifically includes the following steps.
  • step S1 a substrate is selected, and a first diaphragm structure is prepared on the first surface of the substrate:
  • the substrate 101 is selected, and a first oxide layer 1071 is deposited on the first surface 101A of the substrate 101, as shown in FIG. 4a.
  • the base 101 is, for example, a semiconductor silicon substrate or other semiconductor material substrates, such as germanium, silicon germanium, silicon carbide, gallium nitride, indium, indium gallium nitride, indium gallium arsenide, indium gallium zinc oxide, Or other element and/or compound semiconductors (for example, III-V compound conductors such as gallium arsenide or indium phosphide) germanium or gallium nitride.
  • a semiconductor silicon substrate or other semiconductor material substrates such as germanium, silicon germanium, silicon carbide, gallium nitride, indium, indium gallium nitride, indium gallium arsenide, indium gallium zinc oxide, Or other element and/or compound semiconductors (for example, III-V compound conductors such as gallium arsenide or indium phosphide) germanium or gallium nitride.
  • the first oxide layer 1071 is, for example, silicon dioxide, and has a thickness of about 1 ⁇ m, and is formed by conventional processes such as thermal oxidation and vapor deposition.
  • a first polysilicon layer 1041 is deposited on the first oxide layer 1071, for example, the first polysilicon layer 1041 has a thickness of about 1 ⁇ m, as shown in FIG. 4b;
  • the first polysilicon 1041 is etched, and according to the structural requirements of the first diaphragm 104, the first polysilicon film 1041 is etched to form the basic structure of the first diaphragm 104, as shown in FIG. 4c.
  • Step S2 preparing a backplane structure on the side of the first diaphragm structure opposite to the first surface of the substrate:
  • a second oxide layer 1072 is deposited on the first diaphragm structure 104, and the second oxide layer 1072 is, for example, 0.5 ⁇ m thick, as shown in FIG. 4d; preferably, in order to prevent the backplate 105 and the first diaphragm For the adhesion of 104, the second oxide layer 1072 can also be etched to form a groove structure prepared by protrusions.
  • the backplane structure includes a first silicon nitride layer 1051, a second polysilicon layer 1052, and a second silicon nitride layer 1053 stacked from bottom to top.
  • the silicon nitride layer 1051 covers the second oxide layer 1071;
  • the first silicon nitride layer 1051 and the second silicon nitride layer 1053 have a thickness of about 0.25 ⁇ m, for example, and the middle second polysilicon layer 1052 has a thickness of about 0.5 ⁇ m, for example. thickness;
  • the backplane material layer is etched to form the acoustic through holes 108 at intervals, as shown in FIG. 4f;
  • the method further includes the step of preparing protrusions on the surface of the second silicon nitride layer 1053 of the backplane.
  • Step S3 a second diaphragm structure is prepared on the side of the back plate structure opposite to the first diaphragm structure;
  • a third oxide layer 1073 is deposited on the upper surface of the backplane and planarized, as shown in FIG. 4g; the planarization referred to in this embodiment is, for example, a chemical mechanical polishing (CMP) process.
  • CMP chemical mechanical polishing
  • the third oxide layer 1073 is etched to form a support member 109 support member deposition hole 1091, the deposition hole 1091 is interposed in the acoustic through hole 108 of the backplane, exposing the upper surface of the first diaphragm structure 104, as shown in FIG. 4h Shown
  • a third silicon nitride layer 1092 is deposited to fill the deposition hole 1091, as shown in FIG. 4i; the thickness of the third silicon nitride layer 1092 is, for example, sufficient to completely fill the deposition hole 1091, about 4 microns;
  • a third polysilicon film 1061 is deposited.
  • the thickness of the third polysilicon film 1061 is, for example, 1 ⁇ m, as shown in FIG. 4k;
  • the sealing step uses, for example, a polymer, HDP oxide layer, or phosphorosilicate glass (PSG) reflow process to form a seal layer, and etch the seal layer to remove the excess seal layer 114 outside the release hole area. As shown in Figure 4n.
  • PSG phosphorosilicate glass
  • the third polysilicon layer 1061 is etched to form the second diaphragm structure 106, which mainly lies in exposing the contact hole regions 1151, 1161 and the edge region 120 of the MEMS microphone substrate 101, as shown in FIG. 4o;
  • Step S4 preparing contact electrodes
  • the first step is to etch the first contact hole 1151 exposing the backplane area, as shown in FIG. 4p, and the edge area 119 is also etched to the same depth;
  • the second step is etching to expose the first diaphragm 104, the second contact hole 1161, and the substrate silicon layer in the edge region of the MEMS microphone, as shown in FIG. 4q;
  • a passivation protection layer 1181 is deposited on the entire device surface, and the passivation layer is, for example, silicon nitride; as shown in FIG. 4r;
  • a conductive contact point is formed on the upper surface, which corresponds to the lead-out electrode 115 of the first diaphragm 104, the lead-out electrode 116 of the second diaphragm structure 106, and the lead-out electrode 117 of the back plate structure 105;
  • Step 5 forming the back cavity
  • the back surface of the substrate is thinned, for example, the back surface of the substrate 101 is thinned by a grinding process
  • the method further includes the step of forming a through hole 119 penetrating the support in the central area of the device to form the MEMS microphone as shown in FIG.
  • the preparation of the dual-diaphragm MEMS microphone is completed using a standard semiconductor process, which is easy to integrate with other semiconductor devices.

Abstract

本发明提出一种MEMS麦克风的制备方法，包括如下步骤：选择基底，在所述基底的第一表面上制备第一振膜结构；在所述第一振膜结构的与所述基底的第一表面相对的侧面间隔制备背板结构，所述第一振膜结构与所述背板结构之间具有第一间隙；在所述背板结构的与所述第一振膜结构相对的侧面间隔制备第二振膜结构，所述第二振膜结构与所述背板结构之间具有第二间隙；在所述第二振膜结构的与所述背板结构相对的侧面制备电极；刻蚀所述基底的与所述第一表面相对的第二表面，形成背腔。

Description

MEMS麦克风制造方法 技术领域
本发明涉及麦克风技术，特别地，涉及一种微机电系统(Micro-Electro-Mechanic System,MEMS)麦克风的制造方法。
 背景技术
随着无线通讯的发展，用户对移动电话的通话质量要求越来越高，麦克风作为移动电话的语音拾取装置，其设计的好坏直接影响移动电话的通话质量。
由于MEMS技术具有小型化、易集成、高性能、低成本等特点，使其获得业界青睐，MEMS麦克风在当前的移动电话中应用较为广泛；常见的MEMS麦克风为电容式，即包括振膜和背板，二者构成MEMS声传感电容，且MEMS声传感电容进一步通过连接盘连接到处理芯片以将声传感信号输出给处理芯片进行信号处理。为了进一步提高MEMS麦克风的性能，现有技术提出了双振膜MEMS麦克风结构，即利用两层振膜分别与背板构成电容结构。基于硅技术的MEMS麦克风中，上述MEMS麦克风的振膜和背板是在同一个硅基座并利用半导体制作工艺制作而成，且在制作过程中还包括形成声腔、背腔、声学孔、透气孔和连接盘等工艺步骤。
由于MEMS麦克风的每一个制作工艺步骤是在同一个硅基座制作形成，因此必须在前一个工艺步骤完成之后方可进行下一个工艺步骤，此将导致MEMS麦克风的整体制造效率较低。
 技术问题
基于这些问题，有必要提供一种新的MEMS麦克风双振膜结构的制造方法，以提高制造效率。
 技术解决方案
为解决上述技术问题，本发明提供一种可以提高MEMS麦克风整体制造效率的MEMS麦克风的制造方法。 
具体地，本发明提出的方案如下：
一种MEMS麦克风的制备方法，包括如下步骤：
选择基底，在所述基底的第一表面上沉积第一氧化层；
在所述第一氧化层的表面上沉积第一多晶硅层并图形化该第一多晶硅层以形成第一振膜结构；
在所述第一振膜结构的表面沉积第二氧化层；
在所述第二氧化层的表面沉积背板材质层，
图形化所述背板材质层，在所述背板材质层的中间主体区域形成多个声学通孔;
在所述背板结构上沉积第三氧化层，并平坦化所述第三氧化层；
图形化所述第三氧化层、第二氧化层，形成介于所述声学通孔之间的支撑件沉积孔，所述支撑件沉积孔露出所述第一振膜结构；
沉积支撑件材质层，以填充所述支撑件沉积孔；
平坦化所述第三氧化层表面，以去除所述支撑件沉积孔之外的支撑件材质层;
在平坦化的所述第三氧化层表面沉积第三多晶硅层以形成第二振膜结构；
图形化所述第三多晶硅层以形成多个释放孔；
经所述释放孔去除所述第一多晶硅层至第三多晶硅层之间、位于所述背板中间主体区域范围内的第二、第三氧化层，以形成内腔；
在所述第三多晶硅层上沉积密封材质层以密封所述释放孔，并图形化该密封材质层以去除多余的部分；
制备所述第一振膜结构、第二振膜结构、背板结构的引出电极；
背面刻蚀所述基底，形成对应于所述背板结构中间主体区域的背腔结构。
进一步地，所述沉积背板材质层包括依次沉积第一氮化硅层、第二多晶硅层、第二氮化硅层。
进一步地，所述制备所述第一振膜结构、第二振膜结构、背板结构的引出电极包括：
刻蚀形成第一振膜结构、背板结构、第二振膜结构的电极引出孔；
沉积并图形化电极层，形成第一振膜结构的第一引出电极、第二振膜结构的第二引出电极、背板结构的第三引出电极。
进一步地，所述形成背腔，包括：
从所述基底的第二表面减薄并刻蚀所述基底；
去除所述第一振膜结构下方对应所述背腔区域的第一氧化层。
进一步地，还包括在形成电极引出孔之后沉积钝化保护层的步骤。
进一步地，还包括至少一个贯通所述第一振膜结构、所述支撑件、所述第二振膜结构的通孔，该通孔连通所述背腔与外界环境。
进一步地，还包括在所述背板结构的中间主体区域上下表面形成凸起的步骤。
进一步地，所述支撑件的材质包括氮化硅。
进一步地，所述电极的材质包括Cr、Au。
 有益效果
本发明提出了一种具有双振膜结构的MEMS麦克风的制备方法，通过标准的半导体工艺制备，易于与其它半导体器件集成。
 附图说明
图1为本发明其中一实施例的MEMS麦克风结构示意图；
图2为本发明另一实施例的MEMS麦克风结构示意图；
图3为本发明其中一实施例涉及的MEMS麦克风的制备流程图；
图4a-图4v为本发明其中一实施例涉及的MEMS麦克风制备工艺示意图。
 本发明的实施方式
下面将结合本发明实施例中的附图，对本发明实施例中的技术方案进行清楚、完整地描述，显然，所描述的实施例仅是本发明的一部分实施例，而不是全部的实施例。基于本发明中的实施例，本领域普通技术人员在没有做出创造性劳动前提下所获得的所有其它实施例，都属于本发明保护的范围。
请参阅图1-2，利用本发明所提出的制造方法所制备的MEMS麦克风结构100包括基底101以及设置在基底101上并与基底101绝缘相连的电容系统103。
基底101的材质优选为半导体材料，例如硅，其具有背腔102、第一表面101A以及与第一表面相对的第二表面101B，基底101的第一表面101A上设有绝缘层107，背腔102贯通绝缘层107、及基底101的第一、第二表面。其中背腔102可以通过体硅工艺或干法腐蚀形成。
电容系统103包括背板105以及与背板105相对且分别设置在背板105两侧的第一振膜104和第二振膜106，第一振膜104和背板105之间、第二振膜106和背板105之间、第一振膜104和基底101之间均设有绝缘层107。背板105的中央主体区域包括间隔设置的声学通孔108，在本发明中，背板105的中央主体区域例如为对应背腔102所在的区域，此区域之外的为背板105的边缘区域。支撑件109穿过该声学通孔将第一振膜104和第二振膜106固定连接。具体地，支撑件109分别抵接第一振膜104的顶表面和第二振膜106的底表面。绝缘层107将第一振膜104和背板105分隔一定距离并形成第一间隙110，将第二振膜106和背板105分隔一定距离并形成第二间隙111。声学通孔108将第一间隙110和第二间隙111贯通形成内腔112。在MEMS麦克风通电工作时，第一振膜104与背板105、第二振膜106与背板105会带上极性相反的电荷，从而形成电容，当第一振膜104和第二振膜106在声波的作用下产生振动，背板105与第一振膜104和第二振膜106之间的距离会发生变化，从而导致电容系统的电容发生改变，进而将声波信号转化为了电信号，实现麦克风的相应功能。
在本实施例中，第一振膜104和第二振膜 106是方形的、圆形的或者椭圆形，至少一个支撑件109被设置在第一振膜104的底表面与第二振膜106的顶表面之间。
该支撑件109设置为穿过背板105的声学通孔108将第一振膜104和第二振膜106固定连接；即支撑件109不与背板105接触，不受背板105的影响。
该支撑件109可以通过各种制备技术被形成在第一振膜104的顶表面之上，例如物理蒸汽沉积、电化学沉积、化学蒸汽沉积和分子束外延。 
该支撑件109可以由诸如硅之类的半导体材料组成或者可以包括例如硅之类的半导体材料。比如锗、硅锗、碳化硅、氮化镓、铟、氮化铟镓、砷化铟镓、氧化铟镓锌、或其他元素和/或化合物半导体(例如，例如砷化镓或磷化铟之类的III-V化合物半导体、或II-VI化合物半导体、或三元化合物半导体、或四元化合物半导体)。也可以由如下各项中的至少一种组成或者可以包括如下各项中的至少一种：金属、电介质材料、压电材料、压阻材料和铁电材料。也可以是由介质材料如氮化硅制成。
根据各个实施例，该支撑件109可以分别与第一振膜104和第二振膜106一体成型。 
根据各个实施例，本发明的第二振膜106包括若干释放孔113，并采用电介质材料114封闭该释放孔113。
根据各个实施例，还包括第一振膜104、第二振膜106、背板105的引出电极，相应地，分别为第一电极115、第二电极116、第三电极117。
根据各个实施例，还包括表面钝化保护层118。
参见图2，还包括贯通第一振膜104、支撑件109、第二振膜106的通孔119，该通孔119例如设置在第一振膜104、第二振膜106的中心位置，连通背腔102与外界环境，使得第一振膜104、第二振膜106的外表压力一致。
参阅图3-4，其为本发明提供的MEMS麦克风的制造方法的一种实施例的流程图，该制造方法用来制造如图1或者图2所示的麦克风100，具体包括如下步骤。
步骤S1，选择基底，在基底的第一表面上制备第一振膜结构：
具体地，包括如下子步骤：
S11,选择基底101，并在该基底101的第一表面101A上沉积第一氧化层1071，如图4a所示。
该基底101例如是半导体硅衬底，也可以是其它半导体材质衬底，比如：锗、硅锗、碳化硅、氮化镓、铟、氮化铟镓、砷化铟镓、氧化铟镓锌、或其他元素和/或化合物半导体(例如，例如砷化镓或磷化铟之类的III-V化合导体)锗或者氮化镓之类。
该第一氧化层1071例如为二氧化硅，厚度约为1µm，采用热氧化、气相沉积等常规工艺形成。
S12，在该第一氧化层1071上沉积第一多晶硅层1041，该第一多晶硅层1041例如厚度约为1µm，如图4b所示；
S13，刻蚀第一多晶硅1041，根据第一振膜104的结构要求，刻蚀第一多晶硅膜1041，形成第一振膜104的基本结构，如图4c所示。
步骤S2，在所述第一振膜结构的与所述基底的第一表面相对的侧面间隔制备背板结构：
具体地，包括如下子步骤：
S21,在所述第一振膜结构104上沉积第二氧化层1072，该第二氧化层1072例如为0.5µm厚，如图4d所示；优选地，为了防止背板105与第一振膜104的粘附，还可以刻蚀该第二氧化层1072形成凸起制备的凹槽结构。
S22，沉积背板材质层，在本实施例中背板结构包括从下向上叠置的第一氮化硅层1051、第二多晶硅层1052、第二氮化硅层1053，其中第一氮化硅层1051覆盖第二氧化层1071；第一氮化硅层1051、第二氮化硅层1053例如具有约0.25µm的厚度，中间的第二多晶硅层1052例如具有约0.5µm的厚度；
S23，刻蚀背板材质层，形成间隔设置的声学通孔108，如图4f所示；
优选地，还包括在背板的第二氮化硅层1053表面制备凸起的步骤。
步骤S3，在所述背板结构的与所述第一振膜结构相对的侧面间隔制备第二振膜结构；
具体地，包括如下子步骤：
S31,在背板的上表面沉积第三氧化层1073，并平坦化，如图4g所示；本实施例中所指的平坦化例如采用化学机械抛光（CMP）工艺。
S32,刻蚀第三氧化层1073，形成支撑件109支撑件沉积孔1091，该沉积孔1091介于背板的声学通孔108之中，露出第一振膜结构104的上表面，如图4h所示；
S33,沉积第三氮化硅层1092，以填满所述沉积孔1091，如图4i所示；所述第三氮化硅层1092的厚度例如满足完全填满沉积孔1091，约4微米；
S34,去除支撑件沉积孔1091的之外的第三氮化硅层1092，比如采用CMP工艺，如图4j所示；
S35，沉积第三多晶硅薄膜1061，第三多晶硅薄膜1061的厚度例如为1µm，如图4k所示；
S36，刻蚀所述第三多晶硅薄膜1061层，形成释放孔113；显然，释放孔位于支撑件109之外的位置，该释放孔用于去除第一多晶硅层1041和第三多晶硅层1061之间的，位于中央主体区域的氧化层，如图4l所示。
S37，释放氧化层，比如采用BOE溶液或者HF气相刻蚀技术，去除第三多晶硅下方的氧化层，直至露出第一多晶硅层；形成介于第一多晶硅层和背板之间的第一隔离间隙以及第三多晶硅和背板之间的第二隔离间隙，由于背板上声学通孔108的尺寸大于支撑件109的尺寸，所以第一多晶硅层1041和第三多晶硅层1061之间形成连通的腔体112，如图4m所示。
S38，密封释放孔，该密封步骤比如采用聚合物、HDP氧化层、或者磷硅玻璃（PSG）回流工艺形成密封层，并刻蚀该密封层，去除释放孔区域之外多余的密封层114，如图4n所示。
S39，刻蚀第三多晶硅层1061，以形成第二振膜结构106，主要在于露出接触孔区域1151、1161以及MEMS麦克风基底101的边缘区域120，如图4o所示；
步骤S4，制备接触电极
具体地，包括如下子步骤：
S41,刻蚀接触孔，第一步先刻蚀露出背板区域的第一接触孔1151，如图4p所示，同时将边缘区域119刻蚀同样的深度；第二步刻蚀露出第一振膜104的第二接触孔1161、以及MEMS麦克风的边缘区域的衬底硅层，如图4q所示；
S42,在整个器件表面沉积钝化保护层1181，该钝化层例如为氮化硅；如图4r所示；
S43,刻蚀钝化层，露出第一多晶层、第二多晶层、第三多晶层的接触区域1152、1171、1162，此外，如果TBD为氧化物，则需要保留TBD层上的钝化层；如图4s所示；
S44,沉积金属层并图形化该金属层，该金属层例如为Cr、Cu合金，图形化的金属层使得第一多晶硅层、第二多晶硅层、第三多晶硅在器件的上表面形成导电接触点，即对应于第一振膜104的引出电极115、第二振膜结构106的引出电极116、背板结构105的引出电极117；
步骤5，形成背腔
具体地，包括如下步骤：
S51,基底背面减薄，例如采用研磨工艺将基底101的背面进行减薄；
S52,图形化基底第二表面101B并进行刻蚀，形成背腔区域102，刻蚀停止于第一氧化层1071；如图4u所示；
S53,去除背腔区域第一氧化层1071，完成MEMS麦克风制造，如图4v所示。
优选地，还包括形成贯通器件中央区域的支撑件的通孔119的步骤，以形成如图2所示的MEMS麦克风。
在本发明提供的MEMS麦克风的制造方法中，利用标准的半导体工艺完成了双振膜MEMS麦克风的制备，易于与其它半导体器件集成。  
以上所述仅为本发明的实施例，并非因此限制本发明的专利范围，凡是利用本发明说明书及附图内容所作的等效结构或等效流程变换，或直接或间接运用在其它相关的技术领域，均同理包括在本发明的专利保护范围内。

Claims (9)

  1. 一种MEMS麦克风的制备方法，其特征在于，包括如下步骤：
    选择基底，在所述基底的第一表面上沉积第一氧化层；
    在所述第一氧化层的表面上沉积第一多晶硅层并图形化该第一多晶硅层以形成第一振膜结构；
    在所述第一振膜结构的表面沉积第二氧化层；
    在所述第二氧化层的表面沉积背板材质层，
    图形化所述背板材质层，在所述背板材质层的中间主体区域形成多个声学通孔;
    在所述背板结构上沉积第三氧化层，并平坦化所述第三氧化层；
    图形化所述第三氧化层、第二氧化层，形成介于所述声学通孔之间的支撑件沉积孔，所述支撑件沉积孔露出所述第一振膜结构；
    沉积支撑件材质层，以填充所述支撑件沉积孔；
    平坦化所述第三氧化层表面，以去除所述支撑件沉积孔之外的支撑件材质层;
    在平坦化的所述第三氧化层表面沉积第三多晶硅层以形成第二振膜结构；
    图形化所述第三多晶硅层以形成多个释放孔；
    经所述释放孔去除所述第一多晶硅层至第三多晶硅层之间、位于所述背板中间主体区域范围内的第二、第三氧化层，以形成内腔；
    在所述第三多晶硅层上沉积密封材质层以密封所述释放孔，并图形化该密封材质层以去除多余的部分；
    制备所述第一振膜结构、第二振膜结构、背板结构的引出电极；
    背面刻蚀所述基底，形成对应于所述背板结构中间主体区域的背腔结构。
  2. 根据权利要求1所述的MEMS麦克风的制备方法，其特征在于，所述沉积背板材质层包括依次沉积第一氮化硅层、第二多晶硅层、第二氮化硅层。
  3. 根据权利要求1所述的MEMS麦克风的制备方法，其特征在于，所述制备所述第一振膜结构、第二振膜结构、背板结构的引出电极包括：
    刻蚀形成第一振膜结构、背板结构、第二振膜结构的电极引出孔；
    沉积并图形化电极层，形成第一振膜结构的第一引出电极、第二振膜结构的第二引出电极、背板结构的第三引出电极。
  4. 根据权利要求1所述的MEMS麦克风的制备方法，其特征在于，所述形成背腔，包括：
    从所述基底的第二表面减薄并刻蚀所述基底；
    去除所述第一振膜结构下方对应所述背腔区域的第一氧化层。
  5. 根据权利要求1所述的MEMS麦克风的制备方法，其特征在于，还包括在形成电极引出孔之后沉积钝化保护层的步骤。
  6. 根据权利要求1所述的MEMS麦克风的制备方法，其特征在于，还包括至少一个贯通所述第一振膜结构、所述支撑件、所述第二振膜结构的通孔，该通孔连通所述背腔与外界环境。
  7. 根据权利要求1所述的MEMS麦克风的制备方法，其特征在于，还包括在所述背板结构的中间主体区域上下表面形成凸起的步骤。
  8. 根据权利要求1所述的MEMS麦克风的制备方法，其特征在于，所述支撑件的材质包括氮化硅。
  9. 根据权利要求1所述的MEMS麦克风的制备方法，其特征在于，所述电极的材质包括Cr、Au。
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CN106954164A (zh) * 2016-01-06 2017-07-14 中芯国际集成电路制造(上海)有限公司 麦克风结构及其制造方法
CN105792084A (zh) * 2016-04-26 2016-07-20 瑞声声学科技(深圳)有限公司 Mems麦克风及其制造方法
CN110012409A (zh) * 2018-12-31 2019-07-12 瑞声科技(新加坡)有限公司 Mems麦克风制造方法

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