WO2022007191A1 - 扬声器的制作方法 - Google Patents

扬声器的制作方法 Download PDF

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Publication number
WO2022007191A1
WO2022007191A1 PCT/CN2020/115242 CN2020115242W WO2022007191A1 WO 2022007191 A1 WO2022007191 A1 WO 2022007191A1 CN 2020115242 W CN2020115242 W CN 2020115242W WO 2022007191 A1 WO2022007191 A1 WO 2022007191A1
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WIPO (PCT)
Prior art keywords
cavity
piston
etching
layer
manufacturing
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PCT/CN2020/115242
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English (en)
French (fr)
Inventor
程诗阳
朱国
但强
李杨
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瑞声声学科技(深圳)有限公司
瑞声科技（南京）有限公司
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Publication of WO2022007191A1 publication Critical patent/WO2022007191A1/zh

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Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B81—MICROSTRUCTURAL TECHNOLOGY
    • B81B—MICROSTRUCTURAL DEVICES OR SYSTEMS, e.g. MICROMECHANICAL DEVICES
    • B81B7/00—Microstructural systems; Auxiliary parts of microstructural devices or systems
    • B81B7/02—Microstructural systems; Auxiliary parts of microstructural devices or systems containing distinct electrical or optical devices of particular relevance for their function, e.g. microelectro-mechanical systems [MEMS]
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B81—MICROSTRUCTURAL TECHNOLOGY
    • B81C—PROCESSES OR APPARATUS SPECIALLY ADAPTED FOR THE MANUFACTURE OR TREATMENT OF MICROSTRUCTURAL DEVICES OR SYSTEMS
    • B81C1/00—Manufacture or treatment of devices or systems in or on a substrate
    • B81C1/00015—Manufacture or treatment of devices or systems in or on a substrate for manufacturing microsystems
    • B81C1/00023—Manufacture or treatment of devices or systems in or on a substrate for manufacturing microsystems without movable or flexible elements
    • B81C1/00047—Cavities
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B81—MICROSTRUCTURAL TECHNOLOGY
    • B81C—PROCESSES OR APPARATUS SPECIALLY ADAPTED FOR THE MANUFACTURE OR TREATMENT OF MICROSTRUCTURAL DEVICES OR SYSTEMS
    • B81C1/00—Manufacture or treatment of devices or systems in or on a substrate
    • B81C1/00015—Manufacture or treatment of devices or systems in or on a substrate for manufacturing microsystems
    • B81C1/00134—Manufacture or treatment of devices or systems in or on a substrate for manufacturing microsystems comprising flexible or deformable structures
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B81—MICROSTRUCTURAL TECHNOLOGY
    • B81B—MICROSTRUCTURAL DEVICES OR SYSTEMS, e.g. MICROMECHANICAL DEVICES
    • B81B2201/00—Specific applications of microelectromechanical systems
    • B81B2201/02—Sensors
    • B81B2201/0257—Microphones or microspeakers

Definitions

  • the invention relates to the field of acoustic-electrical conversion, in particular to a method for manufacturing a loudspeaker.
  • Microspeakers based on MEMS technology are a type of loudspeakers that combine the advantages of large frequency bandwidth and high sound quality to bring extremely high-quality acoustic performance. In addition, they are very small in size and can be easily integrated into headphones.
  • the method for manufacturing the speaker generally relies on a wafer bonding process, which combines two or even multiple silicon wafers together, and forms its internal three-dimensional structure through multi-step processing.
  • the piston rod is a transmission component, and the high-speed reciprocating motion will accelerate the failure process; due to the large total thickness of the two silicon wafers, a large degree of silicon wafer thinning needs to be performed after bonding, and the thinning thickness may As high as several hundred microns, it brings a lot of challenges to the process, and it is easy to cause the wafer to be scrapped; the etching of the piston plate after bonding will cause one end of the piston plate to be parallel to the end face of the substrate, so that the piston plate vibrates part of the stroke Exposed outside the cavity, resulting in a large amount of air leakage, affecting the audio output performance of the speaker.
  • the purpose of the present invention is to provide a method for manufacturing a loudspeaker with better reliability.
  • the present invention provides a method for manufacturing a loudspeaker.
  • the loudspeaker includes a vibrating membrane, a piezoelectric driver formed on the vibrating membrane and driving the vibrating membrane to vibrate, and a piezoelectric driver fixed on the vibrating membrane away from the vibrating membrane.
  • Step S1 etching the piston rod and the first cavity: prepare a silicon wafer, the silicon wafer includes a first surface and a second surface arranged oppositely, and the first surface is etched and formed. the piston connecting rod and the first cavity;
  • Step S2 depositing a support layer: depositing a support layer material on the side of the silicon wafer where the piston rod and the first cavity are formed, and forming a support layer to fill the first cavity;
  • Step S3 surface planarization: using chemical mechanical polishing process to remove the part of the support layer higher than the piston connecting rod, so that the height of the support layer and the piston connecting rod is consistent;
  • Step S4 forming the vibrating film: depositing a vibrating film material on the piston connecting rod and the support layer to form the vibrating film;
  • Step S5 forming the piezoelectric driver: depositing a piezoelectric driver material on the side of the diaphragm away from the first cavity to form the piezoelectric driver;
  • Step S6 etching the piston plate: etching the piston plate on the second surface and forming the second cavity and the gap to expose the support layer to the gap;
  • Step S7 release of the first cavity and the piston rod: chemical etching is used to remove the support layer to release the first cavity and the piston rod.
  • the step S1 includes the following steps:
  • Step S1a preparing the silicon wafer, and depositing photoresist on the first surface according to the shape of the first cavity and the piston connecting rod to form a first photoresist layer;
  • Step S1b using an ion implantation process to implant ions into the first surface not covered by the first photoresist layer to form an ion layer, the thickness of the ion layer is consistent with the height of the piston rod, and the ions are Formation of Group III or Group V elements;
  • Step S1c etching the ion layer to simultaneously form the piston rod and the first cavity;
  • Step S1d peeling off the first photoresist layer.
  • the ions are formed from any one of phosphorus, arsenic and boron.
  • the step S3 includes the following steps:
  • Step S3a depositing a buffer layer material on the side of the support layer away from the first cavity to form a buffer layer, the thickness of the buffer layer is smaller than the thickness of the support layer, and the buffer layer material includes silicon oxide, at least one of silicon nitride, silicon oxynitride or metal nitride;
  • Step S3b forming a second photoresist layer on the side of the buffer layer away from the support layer, and the second photoresist layer is disposed opposite to the first cavity;
  • Step S3c using a dry etching or wet etching process to remove the buffer layer not covered by the second photoresist layer;
  • Step S3d peeling off the second photoresist layer
  • Step S3e removing the buffer layer and the part of the support layer higher than the piston rod by using a chemical mechanical polishing process, so that the height of the support layer and the piston rod can be kept the same.
  • the step S6 includes the following steps:
  • Step S6a depositing any one of silicon oxide, silicon nitride and silicon oxynitride on the second surface and etching to form a hard mask, the orthographic projection of the hard mask to the piston plate is the same as the piston plate coincide;
  • Step S6b forming a third photoresist layer on the side of the substrate away from the diaphragm;
  • Step S6c etching the second surface not covered by the hard mask and the third photoresist to form the gap, etching the hard mask and the second surface covered by the hard mask to form the piston plate and the second cavity.
  • Step S6d peeling off the third photoresist layer.
  • the rate of etching the first hard mask is lower than the rate of etching the silicon wafer.
  • the manufacturing method of the speaker further includes step S0 of pre-cleaning the silicon wafer.
  • the etching depth is 0.1 ⁇ m-100 ⁇ m.
  • the material of the support layer is silicon oxide or silicon oxynitride.
  • the diaphragm material includes at least one of polycrystalline silicon, single crystal silicon, silicon nitride and amorphous silicon.
  • the thickness of the piston plate is 1 ⁇ m-100 ⁇ m.
  • the speaker manufacturing method of the present invention Compared with the related art, in the speaker manufacturing method of the present invention, only one silicon wafer is used to etch the piston connecting rod and the cavity to form the diaphragm and the piezoelectric driver, the process flow is relatively simple, and the yield is higher. ; And the error is small and the precision is high.
  • the prepared loudspeaker has better reliability and balance performance; when the piston plate vibrates, the movement stroke of the piston plate is all located in the cavity, and the sounding effect of the loudspeaker is better.
  • FIG. 1 is a schematic diagram of a three-dimensional structure of a speaker according to the present invention.
  • Fig. 2 is the sectional view of the loudspeaker of the present invention
  • Fig. 3 is the flow chart of the manufacture method of loudspeaker of the present invention.
  • FIG. 4 is a schematic structural diagram in the flow of the manufacturing method of the loudspeaker of the present invention.
  • Fig. 5 is the flow chart of another step S1 of the manufacturing method of the loudspeaker of the present invention.
  • FIG. 6 is a schematic structural diagram of another step S1 in the process of the manufacturing method of the speaker according to the present invention.
  • Fig. 7 is the flow chart of another step S3 of the manufacturing method of the loudspeaker of the present invention.
  • FIG. 8 is a schematic structural diagram of another step S3 in the process of the speaker manufacturing method of the present invention.
  • FIG. 10 is a schematic structural diagram of another step S6 in the process of the manufacturing method of the speaker according to the present invention.
  • the present invention provides a method for manufacturing a speaker.
  • the speaker 100 includes a vibrating membrane 1, a piezoelectric driver 2 formed on the vibrating membrane 1 and driving the vibrating membrane 1 to vibrate, fixed on the side of the vibrating membrane 1 away from the piezoelectric driver 2 and connected to the vibrating membrane 1.
  • the diaphragm 1 encloses the substrate 3 of the cavity 10, the piston plate 4 and the piston connecting rod 5 accommodated in the cavity 10; one end of the piston connecting rod 5 is fixed to the diaphragm 1, and the other end is fixed on the piston plate 4; the piston plate 4 divides the cavity 10 into a first cavity 10a close to the diaphragm 1 and a second cavity 10b away from the diaphragm 1, the piston plate A gap 10c is formed between 4 and the substrate 3.
  • the piezoelectric driver 2 includes a first electrode 23 , a piezoelectric layer 22 and a second electrode 21 sequentially stacked on the diaphragm 1 , and the piezoelectric layer 22 is made of aluminum nitride or zinc oxide. .
  • the manufacturing method of the speaker 100 includes the following steps:
  • step S0 as shown in FIG. 4a, a silicon wafer 6 is prepared, and the silicon wafer 6 is pre-cleaned.
  • Step S1 etching the piston rod 5 and the first cavity 10a: preparing a silicon wafer 6, the silicon wafer 6 includes a first surface 6a and a second surface 6b arranged oppositely, and the first surface 6a and the second surface 6b are oppositely arranged.
  • the piston connecting rod 5 and the first cavity 10a are etched and formed on the surface 6a, as shown in FIG. 4b.
  • the etching depth is 0.1 ⁇ m-100 ⁇ m.
  • the etching depth can also be selected according to the actual needs of the piston rod 5 and the first cavity 10a.
  • this embodiment also provides a step S1 that can ensure that the etching depth is equal to the design length of the piston rod 5 and improve the uniformity of the device size on the entire silicon wafer 6, as shown in FIG. 5 and FIG. 6 .
  • step S1 includes the following steps:
  • Step S1a prepare a silicon wafer 6, the silicon wafer 6 includes a first surface 6a and a second surface 6b arranged opposite to each other, and the first cavity 10a and the piston are connected on the first surface 6a by pressing the first cavity 10a.
  • the shape of the rod 5 deposits photoresist to form a first photoresist layer 8, as shown in FIG. 6a.
  • Step S1b using an ion implantation process to implant ions into the first surface not covered by the first photoresist layer 8 to form an ion layer 9, as shown in FIG. 6b.
  • the thickness of the ion layer 9 is consistent with the height of the piston connecting rod 5, and the ions are formed from Group III or Group V elements.
  • the ions are made of any one of phosphorus, arsenic, and boron. form.
  • Step S1c etching the ion layer 9 to form the piston rod 5 and the first cavity 10a, as shown in FIG. 6c.
  • Step S1d peeling off the first photoresist layer 8, as shown in FIG. 6d.
  • Step S2 depositing a support layer 7: as shown in FIG. 4c, deposit a support layer material on the side of the silicon wafer 6 where the piston connecting rod 5 and the first cavity 10a are formed, and form a support layer 7 to fill the In the first cavity 10a, in this embodiment, the material of the support layer is silicon oxide or silicon oxynitride.
  • the deposition thickness of the support layer 7 is appropriately selected according to the etching depth in step 1, and is generally slightly larger than the etching depth.
  • Step S3 surface planarization: remove the part of the support layer 7 higher than the piston connecting rod 5 by chemical mechanical polishing process to keep the height of the support layer 7 and the piston connecting rod 5 consistent, as shown in Figure 4d shown.
  • step S3 due to the different hardness and other physicochemical properties of silicon and silicon oxide, the grinding and polishing rate of silicon dioxide is usually faster, so that when the grinding disc rests on the silicon surface, the silicon oxide area has formed a depression, thus A completely flat surface cannot be formed. Therefore, the present invention also provides a step S3, as shown in FIG. 7 and FIG. 8, including the following steps:
  • Step S3a As shown in FIG. 8a, deposit a buffer layer material on the side of the support layer 7 away from the first cavity 10a to form a buffer layer 9, and the thickness of the buffer layer 9 is smaller than that of the support layer 7.
  • the buffer layer material includes at least one of silicon oxide, silicon nitride, silicon oxynitride or metal nitride.
  • Step S3b As shown in FIG. 8b, a second photoresist layer 11 is formed on the side of the buffer layer 9 away from the support layer 7, the second photoresist layer 11 and the first cavity 10a are formed face setting;
  • Step S3c as shown in FIG. 8c, the buffer layer 9 that is not covered by the second photoresist layer 11 is removed by dry etching or wet etching;
  • Step S3d as shown in FIG. 8d, peeling off the second photoresist layer 11;
  • Step S3e As shown in FIG. 8e, the buffer layer 9 and the part of the support layer 7 higher than the piston rod 5 are removed by chemical mechanical polishing process, so that the support layer 7 and the piston rod 5 are removed. the height remains the same.
  • Step S4 forming the diaphragm 1 : as shown in FIG. 4 e , depositing a diaphragm material on the piston rod 5 and the support layer 7 to form the diaphragm 1 .
  • the diaphragm material includes at least one of polycrystalline silicon, single crystal silicon, silicon nitride and amorphous silicon.
  • Step S5 forming the piezoelectric driver 2: as shown in FIG. 4f, depositing piezoelectric driver material on the side of the diaphragm 1 away from the first cavity 10a to form the piezoelectric driver 2; this embodiment
  • the piezoelectric driver 2 is a sandwich structure, that is, the piezoelectric driver 2 includes a first electrode 23, a piezoelectric layer 22 and a second electrode 21 stacked in sequence.
  • a metal material is used.
  • the first electrode 23 is deposited
  • the piezoelectric layer 22 is deposited using piezoelectric materials such as aluminum nitride and zinc oxide
  • the second electrode 21 is deposited using metal materials.
  • Step S6 etching the piston plate 4: as shown in FIG. 4g, the piston plate 4 is etched on the second surface 6b and the second cavity 10b and the gap 10c are formed to make the support The layer 7 is exposed to the gap 10c, and the thickness of the piston plate 4 is 1 ⁇ m-100 ⁇ m.
  • the thickness of the piston plate can also be selected according to actual needs.
  • the present invention also provides a step S6, as shown in FIG. 9 and FIG. 10, including the following steps:
  • Step S6a deposit any one of silicon oxide, silicon nitride and silicon oxynitride on the second surface 6b and etch to form a hard mask 12, the orthographic projection of the hard mask 12 to the piston plate 4 is the same as that of the piston plate 4.
  • the piston plates 4 are overlapped, as shown in Figure 10a.
  • Step S6b As shown in FIG. 10b, a third photoresist layer 13 is formed on the side of the substrate 3 away from the diaphragm 1, and the hard mask 12 and the third photoresist layer 13 are formed. There is a space between them, and the width of the space is equal to the width of the gap 10c.
  • Step S6c As shown in FIG. 10c, etching the second surface b not covered by the hard mask 12 and the third photoresist layer 13 to form the gap 10c, and etching the hard mask 12 and the second surface 6b covered by the hard mask 12 to form the piston plate 4 and the second cavity 10b; preferably, the rate of etching the hard mask 12 is lower than that of etching the silicon wafer 6 s speed.
  • Step S6d as shown in FIG. 10d, the third photoresist layer 13 is peeled off.
  • step S6 Under the action of the double mask (hard mask 12 and the third photoresist layer 13), the area of the gap 10c is etched; due to the existence of the hard mask 12 in the area of the piston plate 4, when the gap 10c After the silicon in the region is completely etched, a certain thickness of silicon still remains in the region of the piston plate 4 . The remaining thickness can be precisely controlled by the etching selectivity ratio and the thickness of the hard mask 12; finally, the third photoresist layer 13 is stripped. In this way, the piston plate 4 and the gap 10c are directly formed by one-step etching, and there is no excessive height difference that would adversely affect the process.
  • Step S7 the release of the first cavity 10a and the piston rod 5: as shown in FIG. 4h, the support layer 7 is removed by chemical etching to release the first cavity 10a and the piston rod 5 5 release.
  • both the piezoelectric layer 22 and the diaphragm 1 are deflected at the same time to drive the piston connecting rod 5 to move, and further push the piston plate 4 to reciprocate, thereby promoting the formation of air. Sound pressure, and finally output audio signal to the outside world.
  • the speaker manufacturing method of the present invention Compared with the related art, in the speaker manufacturing method of the present invention, only one silicon wafer is used to etch the piston connecting rod and the cavity to form the diaphragm and the piezoelectric driver, the process flow is relatively simple, and the yield is higher. ; And the error is small and the precision is high.
  • the prepared loudspeaker has better reliability and balance performance; when the piston plate vibrates, the movement stroke of the piston plate is all located in the cavity, and the sounding effect of the loudspeaker is better.

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  • Microelectronics & Electronic Packaging (AREA)
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Abstract

本发明提供了一种扬声器的制作方法，其包括如下步骤：步骤S1，蚀刻所述活塞连杆以及所述第一空腔；步骤S2，沉积支撑层；步骤S3，表面平坦化；步骤S4，形成所述振膜；步骤S5，形成所述压电驱动器；步骤S6，蚀刻所述活塞板；步骤S7，所述第一空腔以及所述活塞连杆的释放。与相关技术相比，本发明的扬声器的制作方法可靠性更好。

Description

扬声器的制作方法 技术领域
本发明涉及声电转换领域，尤其涉及一种扬声器的制作方法。
 背景技术
基于MEMS技术的微型扬声器是扬声器的一种，其结合了大频率带宽和高音质的优势，能够带来极高品质的声学表现。此外，它们的尺寸非常小，能够很轻松地集成至耳机中。
现有技术中，制作所述扬声器的方法一般依赖于晶圆键合(bonding)工艺，将两片甚至多片硅晶圆结合在一起，并通过多步加工形成其内部的立体结构。
 技术问题
但是现有技术中，由于两片硅晶圆不易直接键合，需要额外沉积金属层，额外增加工艺流程；两片硅晶圆键合时有较大的对准偏差（misalignment），在这种情况下原本应当对接的两部件极有可能发生失配；活塞式扬声器在其工作过程中对平衡性要求很高，若发生失配影响其平衡，极易导致器件的损坏；由于活塞式扬声器的特殊性，其中包含活塞连杆等截面小的元件，在键合中难以形成可靠的结合，容易失效。而且活塞连杆为传动组件，高速的往返运动会加速这种失效过程；由于两片硅晶圆的总厚度很大，在键合后需要进行很大程度的硅晶圆减薄，减薄厚度可能高达几百微米，给工艺带来很大考验，并且容易导致晶圆破片报废；键合后对活塞板的刻蚀会导致活塞板的一端与衬底的端面平行，这样活塞板振动时部分行程暴露于空腔之外，导致大量漏气，影响扬声器的音频输出性能。
因此，实有必要提供一种新的扬声器的制作方法解决上述技术问题。
 技术解决方案
本发明的目的在于提供一种可靠性更好的扬声器的制作方法。
为了达到上述目的，本发明提供了一种扬声器的制作方法，所述扬声器包括振膜、形成于所述振膜之上并驱动所述振膜振动的压电驱动器、固定于所述振膜远离所述压电驱动器一侧并与所述振膜围成空腔的衬底、收容于所述空腔内的活塞板以及活塞连杆；所述活塞连杆一端固定于所述振膜，其另一端固定于所述活塞板；所述活塞板将所述空腔分隔形成靠近所述振膜的第一空腔、远离所述振膜的第二空腔，所述活塞板与所述衬底之间间隔形成间隙；所述扬声器的制作方法包括如下步骤：
步骤S1，蚀刻所述活塞连杆以及所述第一空腔：准备硅晶圆，所述硅晶圆包括相对设置的第一面和第二面，在所述第一面上蚀刻并形成所述活塞连杆以及所述第一空腔；
步骤S2，沉积支撑层：在所述硅晶圆形成所述活塞连杆以及所述第一空腔的一侧沉积支撑层材料并形成支撑层以填充所述第一空腔；
步骤S3，表面平坦化：利用化学机械研磨工艺去除所述支撑层高于所述活塞连杆的部分以使所述支撑层与所述活塞连杆的高度保持一致；
步骤S4，形成所述振膜：在所述活塞连杆以及所述支撑层之上沉积振膜材料以形成所述振膜；
步骤S5，形成所述压电驱动器：在所述振膜远离所述第一空腔的一侧沉积压电驱动器材料以形成所述压电驱动器；
步骤S6，蚀刻所述活塞板：在所述第二面上蚀刻出所述活塞板并形成所述第二空腔和所述间隙以使所述支撑层暴露于所述间隙；
步骤S7，所述第一空腔以及所述活塞连杆的释放：利用化学蚀刻去除所述支撑层以释放所述第一空腔以及所述活塞连杆。
优选的，所述步骤S1包括以下步骤：
步骤S1a：准备所述硅晶圆，在所述第一面上按所述第一空腔和所述活塞连杆的形状堆积光刻胶形成第一光刻胶层；
步骤S1b：利用离子注入工艺将离子注入未被所述第一光刻胶层覆盖的第一面形成离子层，所述离子层的厚度与所述活塞连杆的高度保持一致，所述离子由三族或五族元素形成；
步骤S1c：蚀刻所述离子层以同步形成所述活塞连杆以及所述第一空腔；
步骤S1d：剥离所述第一光刻胶层。
优选的，所述离子由磷、砷、硼中的任意一种形成。
优选的，所述步骤S3包括以下步骤：
步骤S3a：在所述支撑层远离所述第一空腔的一侧沉积缓冲层材料以形成缓冲层，所述缓冲层的厚度小于所述支撑层的厚度，所述缓冲层材料包括氧化硅、氮化硅、氮氧化硅或金属氮化物的至少一种；
步骤S3b：在所述缓冲层远离所述支撑层的一侧形成第二光刻胶层，所述第二光刻胶层与所述第一空腔正对设置；
步骤S3c：利用干法蚀刻或湿法蚀刻工艺去除未被所述第二光刻胶层覆盖的所述缓冲层；
步骤S3d：剥离所述第二光刻胶层；
步骤S3e：利用化学机械研磨工艺去除所述缓冲层以及所述支撑层高于所述活塞连杆的部分以使所述支撑层与所述活塞连杆的高度保持一致。
优选的，所述步骤S6包括以下步骤：
步骤S6a：在所述第二面沉积氧化硅、氮化硅以及氮氧化硅中任意一种材料并蚀刻形成硬掩膜，所述硬掩膜向所述活塞板的正投影与所述活塞板重合；
步骤S6b：在所述衬底远离所述振膜的一侧形成第三光刻胶层；
步骤S6c：蚀刻未被所述硬掩膜与所述第三光刻胶覆盖的所述第二面以形成所述间隙，蚀刻所述硬掩膜以及被所述硬掩膜覆盖的第二面以形成所述活塞板和所述第二空腔。
步骤S6d：剥离第三光刻胶层。
优选的，进行步骤S6c时，蚀刻所述第一硬掩膜的速率小于蚀刻所述硅晶圆的速率。
优选的，所述扬声器的制作方法在进行步骤S1之前还包括步骤S0，对所述硅晶圆进行预清洗。
优选的，在进行步骤S1时，蚀刻深度为0.1μm-100μm。
优选的，在进行步骤S2时，所述支撑层材料为氧化硅或氮氧化硅。
优选的，进行步骤S4时，所述振膜材料包括多晶硅、单晶硅、氮化硅和无定形硅的至少一种。
优选的，在进行步骤S6时，所述活塞板的厚度为1μm-100μm。
 有益效果
与相关技术相比，本发明的扬声器的制作方法中，仅利用一片硅晶圆蚀刻出所述活塞连杆以及空腔，并形成振膜以及压电驱动器，工艺流程相对简单，良率更高；且误差小，精度高。制得的扬声器可靠性及平衡性能更好；当活塞板振动时，其活塞板的运动行程均位于所述空腔内，扬声器的发声效果更好。
 附图说明
为了更清楚地说明本发明实施例中的技术方案，下面将对实施例描述中所需要使用的附图作简单地介绍，显而易见地，下面描述中的附图仅仅是本发明的一些实施例，对于本领域普通技术人员来讲，在不付出创造性劳动的前提下，还可以根据这些附图获得其它的附图，其中：
图1为本发明扬声器立体结构示意图；
图2为本发明扬声器的剖视图；
图3为本发明扬声器的制作方法的流程图；
图4为本发明扬声器的制作方法流程中的结构示意图；
图5为本发明扬声器的制作方法另一步骤S1的流程图；
图6为本发明扬声器的制作方法另一步骤S1流程中的结构示意图；
图7为本发明扬声器的制作方法另一步骤S3的流程图；
图8为本发明扬声器的制作方法另一步骤S3流程中的结构示意图；
图9为本发明扬声器的制作方法另一步骤S6的流程图；
图10为本发明扬声器的制作方法另一步骤S6流程中的结构示意图。
 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。
需要说明的是，各实施例之间的技术方案可相互组合，但必须是以本领域普通技术人员能够实现为基础。
请参阅图1-图10所示，本发明提供了一种扬声器的制作方法。
扬声器100包括振膜1、形成于所述振膜1之上并驱动所述振膜1振动的压电驱动器2、固定于所述振膜1远离所述压电驱动器2一侧并与所述振膜1围成空腔10的衬底3、收容于所述空腔10内的活塞板4以及活塞连杆5；所述活塞连杆5一端固定于所述振膜1，其另一端固定于所述活塞板4；所述活塞板4将所述空腔10分隔形成靠近所述振膜1的第一空腔10a、远离所述振膜1的第二空腔10b，所述活塞板4与所述衬底3之间间隔形成间隙10c。本实施例中所述压电驱动器2包括依次叠设于所述振膜1上的第一电极23、压电层22以及第二电极21，压电层22由氮化铝或氧化锌制成。
所述扬声器100的制作方法包括如下步骤：
步骤S0，如图4a所示，准备硅晶圆6，对所述硅晶圆6进行预清洗。
步骤S1，蚀刻所述活塞连杆5以及所述第一空腔10a：准备硅晶圆6，所述硅晶圆6包括相对设置的第一面6a和第二面6b，在所述第一面6a上蚀刻并形成所述活塞连杆5以及所述第一空腔10a，如图4b所示。优选的，蚀刻深度为0.1μm-100μm，当然也可根据所述活塞连杆5以及所述第一空腔10a的实际需要选择蚀刻深度。
本实施例中，在进行上述步骤S1时，由于缺少刻蚀停止层，无法较好的控制刻蚀终点，从而影响活塞连杆5的实际长度及其在整片硅晶圆6上的均匀性。
因此本实施例还提供一种可以保证刻蚀深度与活塞连杆5的设计长度相当，且提升了整片硅晶圆6上器件尺寸的均匀性的步骤S1，参图5及图6所示，此时步骤S1包括如下步骤：
步骤S1a：准备硅晶圆6，所述硅晶圆6包括相对设置的第一面6a和第二面6b，在所述第一面6a上按所述第一空腔10a和所述活塞连杆5的形状堆积光刻胶形成第一光刻胶层8，如图6a所示。
步骤S1b：利用离子注入工艺将离子注入未被所述第一光刻胶层8覆盖的第一面形成离子层9，如图6b所示。所述离子层9的厚度与所述活塞连杆5的高度保持一致，所述离子由三族或五族元素形成，本实施例中，所述离子由磷、砷、硼中的任意一种形成。
步骤S1c：蚀刻所述离子层9以形成所述活塞连杆5以及所述第一空腔10a，如图6c所示。
步骤S1d：剥离所述第一光刻胶层8，如图6d所示。
步骤S2，沉积支撑层7：如图4c所示，在所述硅晶圆6形成所述活塞连杆5以及所述第一空腔10a的一侧沉积支撑层材料并形成支撑层7以填充所述第一空腔10a，本实施例中，所述支撑层材料为氧化硅或氮氧化硅。支撑层7沉积厚度依据步骤1的刻蚀深度适量选择，一般要略大于刻蚀深度。
步骤S3，表面平坦化：利用化学机械研磨工艺去除所述支撑层7高于所述活塞连杆5的部分以使所述支撑层7与所述活塞连杆5的高度保持一致，如图4d所示。
在进行上述步骤S3时，由于硅和氧化硅的硬度及其他物化性质不同，通常导致二氧化硅的磨抛速率更快，从而当磨盘停靠在硅表面时，氧化硅区域已经形成了凹陷，从而不能形成完全平坦化的表面。因此本发明还提供一种步骤S3，参图7和图8所示，包括如下步骤：
步骤S3a：如图8a所示，在所述支撑层7远离所述第一空腔10a的一侧沉积缓冲层材料以形成缓冲层9，所述缓冲层9的厚度小于所述支撑层7的厚度，所述缓冲层材料包括氧化硅、氮化硅、氮氧化硅或金属氮化物的至少一种。
步骤S3b：如图8b所示，在所述缓冲层9远离所述支撑层7的一侧形成第二光刻胶层11，所述第二光刻胶层11与所述第一空腔10a正对设置；
步骤S3c：如图8c所示，利用干法蚀刻或湿法蚀刻工艺去除未被所述第二光刻胶层11覆盖的所述缓冲层9；
步骤S3d：如图8d所示，剥离所述第二光刻胶层11；
步骤S3e：如图8e所示，利用化学机械研磨工艺去除所述缓冲层9以及所述支撑层7高于所述活塞连杆5的部分以使所述支撑层7与所述活塞连杆5的高度保持一致。
即采用此种步骤S3时，第一空腔10a上方有缓冲层9保护，该区域支撑层7的氧化硅不至于被过度减薄至低于第一面6a面表面，从而抑制了化学机械研磨工艺的凹陷缺陷，形成足够平坦的表面。
步骤S4，形成所述振膜1：如图4e所示，在所述活塞连杆5以及所述支撑层7之上沉积振膜材料以形成所述振膜1。本实施例中，所述振膜材料包括多晶硅、单晶硅、氮化硅和无定形硅的至少一种。
步骤S5，形成所述压电驱动器2：如图4f所示，在所述振膜1远离所述第一空腔10a的一侧沉积压电驱动器材料以形成所述压电驱动器2；本实施例中，所述压电驱动器2为三明治结构，即压电驱动器2包括依次叠设的第一电极23、压电层22以及第二电极21，形成所述压电驱动器2时，利用金属材料沉积第一电极23，利用氮化铝、氧化锌等压电材料沉积压电层22，利用金属材料沉积第二电极21。
步骤S6，蚀刻所述活塞板4：如图4g所示，在所述第二面6b上蚀刻出所述活塞板4并形成所述第二空腔10b和所述间隙10c以使所述支撑层7暴露于所述间隙10c，所述活塞板4的厚度为1μm-100μm，当然也可根据实际需要选择活塞板的厚度。
在进行上述步骤S6时，由于活塞板4区域需要保留一定厚度的硅，而活塞板4周围环绕的区域，即所述间隙10c则需要将硅刻蚀完全。常规工艺需要进行两步刻蚀，存在以下问题：活塞板4区域保留的硅的厚度不易控制，且第二面6b与活塞板4所处位置存在较大高度差（可能超过100微米），在这种情况下光刻胶难以涂覆在不同高度的表面。因此本发明还提供一种步骤S6，参图9和图10所示，包括如下步骤：
步骤S6a：在所述第二面6b沉积氧化硅、氮化硅以及氮氧化硅中任意一种材料并蚀刻形成硬掩膜12，所述硬掩膜12向所述活塞板4的正投影与所述活塞板4重合，如图10a所示。
步骤S6b：如图10b所示，在所述衬底3远离所述振膜1的一侧形成第三光刻胶层13，所述硬掩膜12与所述第三光刻胶层13之间存在间隔，其间隔的宽度与所述间隙10c的宽度相等。
步骤S6c：如图10c所示，蚀刻未被所述硬掩膜12与所述第三光刻胶层13覆盖的所述第二面b以形成所述间隙10c，蚀刻所述硬掩膜12以及被所述硬掩膜12覆盖的第二面6b以形成所述活塞板4和所述第二空腔10b；优选的，蚀刻所述硬掩膜12的速率小于蚀刻所述硅晶圆6的速率。
步骤S6d：如图10d所示，剥离第三光刻胶层13。
采用上述步骤S6时，在双掩模（硬掩膜12以及第三光刻胶层13）的作用下，间隙10c区域被刻蚀；由于活塞板4区域硬掩膜12的存在，当间隙10c区域的硅刻蚀完全后，活塞板4区域依然保留一定厚度的硅。剩余的厚度可以通过刻蚀选择比和硬掩膜12厚度来精确控制；最后剥离第三光刻胶层13。这样就通过一步刻蚀直接形成活塞板4和间隙10c，且不存在高度差过大对工艺产生不利影响。
步骤S7，所述第一空腔10a以及所述活塞连杆5的释放：如图4h所示，利用化学蚀刻去除所述支撑层7以释放所述第一空腔10a以及所述活塞连杆5的释放。
当外界对压电驱动器2传递电信号时，压电驱动器2上的压电层22发生位移以带动振膜1发生位移。由于压电层22和振膜1的弹性模量不同，导致压电层22和振膜1两者同时发生偏转以带动活塞连杆5运动，进一步推动活塞板4做往返运动，从而推动空气形成声压，最后向外界输出音频信号。
与相关技术相比，本发明的扬声器的制作方法中，仅利用一片硅晶圆蚀刻出所述活塞连杆以及空腔，并形成振膜以及压电驱动器，工艺流程相对简单，良率更高；且误差小，精度高。制得的扬声器可靠性及平衡性能更好；当活塞板振动时，其活塞板的运动行程均位于所述空腔内，扬声器的发声效果更好。
以上所述的仅是本发明的实施方式，在此应当指出，对于本领域的普通技术人员来说，在不脱离本发明创造构思的前提下，还可以做出改进，但这些均属于本发明的保护范围。

Claims (11)

  1. 一种扬声器的制作方法，所述扬声器包括振膜、形成于所述振膜之上并驱动所述振膜振动的压电驱动器、固定于所述振膜远离所述压电驱动器一侧并与所述振膜围成空腔的衬底、收容于所述空腔内的活塞板以及活塞连杆；所述活塞连杆一端固定于所述振膜，其另一端固定于所述活塞板；所述活塞板将所述空腔分隔形成靠近所述振膜的第一空腔、远离所述振膜的第二空腔，所述活塞板与所述衬底之间间隔形成间隙；其特征在于，所述扬声器的制作方法包括如下步骤：
    步骤S1，蚀刻所述活塞连杆以及所述第一空腔：准备硅晶圆，所述硅晶圆包括相对设置的第一面和第二面，在所述第一面上蚀刻并形成所述活塞连杆以及所述第一空腔；
    步骤S2，沉积支撑层：在所述硅晶圆形成所述活塞连杆以及所述第一空腔的一侧沉积支撑层材料并形成支撑层以填充所述第一空腔；
    步骤S3，表面平坦化：利用化学机械研磨工艺去除所述支撑层高于所述活塞连杆的部分以使所述支撑层与所述活塞连杆的高度保持一致；
    步骤S4，形成所述振膜：在所述活塞连杆以及所述支撑层之上沉积振膜材料以形成所述振膜；
    步骤S5，形成所述压电驱动器：在所述振膜远离所述第一空腔的一侧沉积压电驱动器材料以形成所述压电驱动器；
    步骤S6，蚀刻所述活塞板：在所述第二面上蚀刻出所述活塞板并形成所述第二空腔和所述间隙以使所述支撑层暴露于所述间隙；
    步骤S7，所述第一空腔以及所述活塞连杆的释放：利用化学蚀刻去除所述支撑层以释放所述第一空腔以及所述活塞连杆。
  2. 根据权利要求1所述的扬声器的制作方法，其特征在于，所述步骤S1包括以下步骤：
    步骤S1a：准备所述硅晶圆，在所述第一面上按所述第一空腔和所述活塞连杆的形状堆积光刻胶形成第一光刻胶层；
    步骤S1b：利用离子注入工艺将离子注入未被所述第一光刻胶层覆盖的第一面形成离子层，所述离子层的厚度与所述活塞连杆的高度保持一致，所述离子由三族或五族元素形成；
    步骤S1c：蚀刻所述离子层以同步形成所述活塞连杆以及所述第一空腔；
    步骤S1d：剥离所述第一光刻胶层。
  3. 根据权利要求2所述的扬声器的制作方法，其特征在于，所述离子由磷、砷、硼中的任意一种形成。
  4. 根据权利要求1所述的扬声器的制作方法，其特征在于，所述步骤S3包括以下步骤：
    步骤S3a：在所述支撑层远离所述第一空腔的一侧沉积缓冲层材料以形成缓冲层，所述缓冲层的厚度小于所述支撑层的厚度，所述缓冲层材料包括氧化硅、氮化硅、氮氧化硅或金属氮化物的至少一种；
    步骤S3b：在所述缓冲层远离所述支撑层的一侧形成第二光刻胶层，所述第二光刻胶层与所述第一空腔正对设置；
    步骤S3c：利用干法蚀刻或湿法蚀刻工艺去除未被所述第二光刻胶层覆盖的所述缓冲层；
    步骤S3d：剥离所述第二光刻胶层；
    步骤S3e：利用化学机械研磨工艺去除所述缓冲层以及所述支撑层高于所述活塞连杆的部分以使所述支撑层与所述活塞连杆的高度保持一致。
  5. 根据权利要求1所述的扬声器的制作方法，其特征在于，所述步骤S6包括以下步骤：
    步骤S6a：在所述第二面沉积氧化硅、氮化硅以及氮氧化硅中任意一种材料并蚀刻形成硬掩膜，所述硬掩膜向所述活塞板的正投影与所述活塞板重合；
    步骤S6b：在所述衬底远离所述振膜的一侧形成第三光刻胶层；
    步骤S6c：蚀刻未被所述硬掩膜与所述第三光刻胶覆盖的所述第二面以形成所述间隙，蚀刻所述硬掩膜以及被所述硬掩膜覆盖的第二面以形成所述活塞板和所述第二空腔；
    步骤S6d：剥离第三光刻胶层。
  6. 根据权利要求5所述的扬声器的制作方法，其特征在于，进行步骤S6c时，蚀刻所述第一硬掩膜的速率小于蚀刻所述硅晶圆的速率。
  7. 根据权利要求1所述的扬声器的制作方法，其特征在于，所述扬声器的制作方法在进行步骤S1之前还包括步骤S0，对所述硅晶圆进行预清洗。
  8. 根据权利要求1所述的扬声器的制作方法，其特征在于，在进行步骤S1时，蚀刻深度为0.1μm-100μm。
  9. 根据权利要求1所述的扬声器的制作方法，其特征在于，在进行步骤S2时，所述支撑层材料为氧化硅或氮氧化硅。
  10. 根据权利要求1所述的扬声器的制作方法，其特征在于，进行步骤S4时，所述振膜材料包括多晶硅、单晶硅、氮化硅和无定形硅的至少一种。
  11. 根据权利要求1所述的扬声器的制作方法，其特征在于，在进行步骤S6时，所述活塞板的厚度为1μm-100μm。
     
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