WO2021128339A1 - 薄膜体声波谐振器 - Google Patents

薄膜体声波谐振器 Download PDF

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Publication number
WO2021128339A1
WO2021128339A1 PCT/CN2019/129418 CN2019129418W WO2021128339A1 WO 2021128339 A1 WO2021128339 A1 WO 2021128339A1 CN 2019129418 W CN2019129418 W CN 2019129418W WO 2021128339 A1 WO2021128339 A1 WO 2021128339A1
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WIPO (PCT)
Prior art keywords
electrode
bulk acoustic
film bulk
outer edge
mass load
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PCT/CN2019/129418
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English (en)
French (fr)
Inventor
窦韶旭
吴珂
韩琦
王超
庄玉召
程诗阳
张丽蓉
杨帅
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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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Priority to PCT/CN2019/129418 priority Critical patent/WO2021128339A1/zh
Publication of WO2021128339A1 publication Critical patent/WO2021128339A1/zh

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    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
    • H03H9/00—Networks comprising electromechanical or electro-acoustic devices; Electromechanical resonators
    • H03H9/02—Details
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
    • H03H9/00—Networks comprising electromechanical or electro-acoustic devices; Electromechanical resonators
    • H03H9/02—Details
    • H03H9/125—Driving means, e.g. electrodes, coils
    • H03H9/13—Driving means, e.g. electrodes, coils for networks consisting of piezoelectric or electrostrictive materials
    • 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
    • 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

Definitions

  • the invention relates to the field of acoustic wave resonators, in particular to a thin-film bulk acoustic wave resonator.
  • the thin film bulk acoustic wave resonator includes: a first electrode 1; a second electrode 2 that must be located near and above the first electrode 1; the first electrode 1 and the The overlap of the second electrode 2 defines an effective area; a piezoelectric sheet 3 inserted between the first electrode 1 and the second electrode 2; must be located at one of the first electrode 1 and the second electrode 2 On one surface of the ring 4; under the first electrode 1 there is a substrate 5 forming a cavity 6 between the first electrode 1 and the substrate 5.
  • This kind of structure has certain difficulties in the micro-machining process, and it is not conducive to ensuring the uniformity of the thickness of the second electrode and the ring structure and the flatness of the film during mass production.
  • the present invention provides a thin film bulk acoustic wave resonator.
  • the thin film bulk acoustic wave resonator includes a first electrode and is located on the first electrode.
  • the upper second electrode and the piezoelectric film located between the first electrode and the second electrode, the film bulk acoustic resonator further includes a substrate and an acoustic reflection structure arranged below the first electrode, An etch stop layer provided above the second electrode and a mass load layer provided above the etch stop layer; the acoustic reflection structure, the first electrode, the piezoelectric film and the second
  • the projection overlap of the electrodes defines the effective area of the film bulk acoustic wave resonator; in any cross section of the film bulk acoustic wave resonator, the inner edge of the mass load layer is located inside the outer edge of the effective area.
  • the outer edge of the mass load layer is flush with the outer edge of the second electrode.
  • the outer edge of the mass load layer is located inside the outer edge of the second electrode.
  • the outer edge of the mass load layer is located outside the outer edge of the second electrode.
  • the thin film bulk acoustic resonator further includes a passivation layer covering the mass load layer and the etch stop layer.
  • the middle portion of the substrate is provided with a groove inwardly, a cavity is formed between the groove and the first electrode, and the cavity constitutes the acoustic reflection structure.
  • the thin-film bulk acoustic resonator provided by the present invention inserts a new etching stop layer between the mass load layer and the second electrode, and the etching stop layer plus the mass load ring ensures that The high quality factor (Quality, Q) value of the device is improved, and the film thickness consistency of the second electrode and the frame structure of the mass load layer is ensured, thereby improving the consistency of the electrical parameters of the device.
  • Q Quality of the device
  • FIG. 1 is a schematic diagram of the structure of a thin film bulk acoustic resonator in the prior art
  • FIG. 2 is a schematic diagram of a cross-sectional structure of a film bulk acoustic resonator provided by Embodiment 1 of the present invention
  • FIG. 3 is a schematic diagram of a cross-sectional structure of a thin film bulk acoustic resonator provided by the second embodiment of the present invention.
  • FIG. 4 is a schematic diagram of a cross-sectional structure of a thin film bulk acoustic resonator provided by Embodiment 3 of the present invention.
  • the film bulk acoustic resonator provided by the present invention includes a first electrode 10, a second electrode 20 located above the first electrode 10, and between the first electrode 10 and the second electrode 20
  • the piezoelectric film 30, the film bulk acoustic wave resonator further includes a substrate 40 arranged below the first electrode 10, an etching stop layer 50 arranged above the second electrode 20, and an etching stop layer 50 arranged above the second electrode 20.
  • the middle part of the substrate 40 is provided with a groove 70 inward, and a cavity is formed between the groove 70 and the first electrode 10, The cavity constitutes an acoustic reflection structure.
  • the projection overlaps of the acoustic reflection structure, the first electrode 10, the piezoelectric film 30, and the second electrode 20 define the effective area of the film bulk acoustic wave resonator.
  • the mass load layer 60 has a frame-shaped structure, and the inner edge 601 of the frame-shaped structure is smaller than the outer edge of the effective area.
  • the outer edge 602 of the mass load layer 60 is flush with the outer edge 202 of the second electrode 20.
  • the outer edge 602 of the mass load layer 60 is located inside the outer edge 202 of the second electrode 20.
  • Example 3 please refer to FIG. 4, the outer edge 602 of the mass load layer 60 is located outside the outer edge 202 of the second electrode 20.
  • the effective area of the film bulk acoustic resonator may be, for example, a cylinder, a tetragon, a pentagonal cylinder, a hexagonal cylinder, or any other shape.
  • the first electrode, the second electrode, The piezoelectric film, the substrate, the etching stop layer and the mass load layer are also arranged according to the regular shape of the film bulk acoustic resonator.
  • the thin film bulk acoustic resonator provided by the present invention inserts a new etching stop layer between the mass load layer and the second electrode.
  • the etching stop layer plus the mass load ring ensures that The high Q value of the device is ensured, and the film thickness consistency of the second electrode and the frame structure of the mass load layer is ensured, thereby improving the consistency of the electrical parameters of the device.

Landscapes

  • Physics & Mathematics (AREA)
  • Acoustics & Sound (AREA)
  • Piezo-Electric Or Mechanical Vibrators, Or Delay Or Filter Circuits (AREA)

Abstract

本发明提供了一种薄膜体声波谐振器，包括第一电极、定位于所述第一电极上方的第二电极及在所述第一电极与所述第二电极之间的压电薄膜，设于所述第一电极下方的衬底和声反射结构、设于所述第二电极上方的刻蚀停止层和设于所述刻蚀停止层上方的质量负载层；所述声反射结构、所述第一电极、所述压电薄膜与所述第二电极的投影重叠界定一有效区域。与现有技术相比，本发明保证了器件高Q值，又保证了第二电极和质量负载层框形结构的膜厚一致性，从而提高了器件电参数的一致性。

Description

薄膜体声波谐振器 技术领域
本发明涉及声波谐振器领域，尤其涉及一种薄膜体声波谐振器。
 背景技术
现有技术中，请参阅图1，该薄膜体声波谐振器包含：一第一电极1；一定位于所述第一电极1附近及上方的第二电极2；所述第一电极1与所述第二电极2的重叠界定一有效面积；一插入所述第一电极1与所述第二电极2之间的压电薄片3；一定位于所述第一电极1和第二电极2中的一个的一表面上的环4；在第一电极1下方有一衬底5在第一电极1和衬底5之间形成空腔6。
 技术问题
该种结构在微机械加工工艺上有一定难度，批量生产时不利于保证第二电极和环结构的厚度一致性和薄膜平整度。
 技术解决方案
针对现有技术中存在的薄膜体声波谐振器结构中的加工难度大的问题，本发明提供一种薄膜体声波谐振器，所述薄膜体声波谐振器包括第一电极、位于所述第一电极上方的第二电极及位于所述第一电极与所述第二电极之间的压电薄膜，所述薄膜体声波谐振器还包括设于所述第一电极下方的衬底和声反射结构、设于所述第二电极上方的刻蚀停止层和设于所述刻蚀停止层上方的质量负载层；所述声反射结构、所述第一电极、所述压电薄膜与所述第二电极的投影重叠界定所述薄膜体声波谐振器工作的有效区域；在所述薄膜体声波谐振器的任一剖面，所述质量负载层的内边沿位于所述有效区域的外边沿的内侧。
优选地，在所述薄膜体声波谐振器的任一剖面，所述质量负载层的外边沿与所述第二电极的外边沿平齐。
优选地，在所述薄膜体声波谐振器的任一剖面，所述质量负载层的外边沿位于所述第二电极的外边沿的内侧。
优选地，在所述薄膜体声波谐振器的任一剖面，所述质量负载层的外边沿位于所述第二电极的外边沿的外侧。
优选地，所述薄膜体声波谐振器还包括覆盖于所述质量负载层和所述刻蚀停止层的钝化层。
优选地，所述衬底的中间部向内设有凹槽，所述凹槽与所述第一电极之间形成空腔，所述空腔构成所述声反射结构。
 有益效果
与现有技术相比，本发明提供的薄膜体声波谐振器，通过在质量负载层和第二电极之间新插入一层刻蚀停止层，所述刻蚀停止层加质量负载环，既保证了器件高品质因数（Quality，Q）值，又保证了第二电极和质量负载层框形结构的膜厚一致性，从而提高了器件电参数的一致性。
 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为现有技术中的薄膜体声波谐振器的结构示意图；
图2为本发明实施例一提供的薄膜体声波谐振器的剖面结构示意图；
图3为本发明实施例二提供的薄膜体声波谐振器的剖面结构示意图；
图4为本发明实施例三提供的薄膜体声波谐振器的剖面结构示意图。
 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。
请参阅图2，本发明提供的薄膜体声波谐振器包括第一电极10、位于所述第一电极10上方的第二电极20及位于所述第一电极10与所述第二电极20之间的压电薄膜30，所述薄膜体声波谐振器还包括设于所述第一电极10下方的衬底40、设于所述第二电极20上方的刻蚀停止层50、设于所述刻蚀停止层50上方的质量负载层60和钝化层80，所述衬底40的中间部向内设有凹槽70，所述凹槽70与所述第一电极10之间形成空腔，所述空腔构成声反射结构。
所述声反射结构、所述第一电极10、所述压电薄膜30与所述第二电极20的投影重叠界定所述薄膜体声波谐振器工作的有效区域。所述质量负载层60呈框形结构，所述框形结构的内边沿601小于所述有效区域的外边沿。
实施例一，请参阅图2，所述质量负载层60的外边沿602与所述第二电极20的外边沿202平齐。
实施例二，请参阅图3，所述质量负载层60的外边沿602位于所述第二电极20的外边沿202的内侧。
实例例三，请参阅图4，所述质量负载层60的外边沿602位于所述第二电极20的外边沿202的外侧。
具体在上述实施例中，所述薄膜体声波谐振器的有效区域可以为例如圆柱体、四方体、五角柱体、六角柱体或其它任意一种形状，所述第一电极、第二电极、压电薄膜、衬底、刻蚀停止层和质量负载层根据所述薄膜体声波谐振器的规则形状同样设置。与现有技术相比，本发明提供的薄膜体声波谐振器，通过在质量负载层和第二电极之间新插入一层刻蚀停止层，所述刻蚀停止层加质量负载环，既保证了器件高Q值，又保证了第二电极和质量负载层框形结构的膜厚一致性，从而提高了器件电参数的一致性。
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 (6)

  1. 一种薄膜体声波谐振器，所述薄膜体声波谐振器包括第一电极、位于所述第一电极上方的第二电极及位于所述第一电极与所述第二电极之间的压电薄膜，其特征在于，所述薄膜体声波谐振器还包括设于所述第一电极下方的衬底和声反射结构、设于所述第二电极上方的刻蚀停止层和设于所述刻蚀停止层上方的质量负载层；所述声反射结构、所述第一电极、所述压电薄膜与所述第二电极的投影重叠界定所述薄膜体声波谐振器工作的有效区域；在所述薄膜体声波谐振器的任一剖面，所述质量负载层的内边沿位于所述有效区域的外边沿的内侧。
  2. 根据权利要求1所述的薄膜体声波谐振器，其特征在于，在所述薄膜体声波谐振器的任一剖面，所述质量负载层的外边沿与所述第二电极的外边沿平齐。
  3. 根据权利要求1所述的薄膜体声波谐振器，其特征在于，在所述薄膜体声波谐振器的任一剖面，所述质量负载层的外边沿位于所述第二电极的外边沿的内侧。
  4. 根据权利要求1所述的薄膜体声波谐振器，其特征在于，在所述薄膜体声波谐振器的任一剖面，所述质量负载层的外边沿位于所述第二电极的外边沿的外侧。
  5. 根据权利要求1所述的薄膜体声波谐振器，其特征在于，所述薄膜体声波谐振器还包括覆盖于所述质量负载层和所述刻蚀停止层的钝化层。
  6. 根据权利要求1所述的薄膜体声波谐振器，其特征在于，所述衬底的中间部向内设有凹槽，所述凹槽与所述第一电极之间形成空腔，所述空腔构成所述声反射结构。
PCT/CN2019/129418 2019-12-27 2019-12-27 薄膜体声波谐振器 WO2021128339A1 (zh)

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Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN1794572A (zh) * 2004-12-22 2006-06-28 安捷伦科技有限公司 用选择性金属蚀刻提高声共振器的性能
CN102075161A (zh) * 2011-01-20 2011-05-25 张�浩 声波器件及其制作方法
US20120091862A1 (en) * 2010-10-15 2012-04-19 Epcos Ag Electrode, Microacoustic Component and Production Method for an Electrode
CN103296993A (zh) * 2013-04-11 2013-09-11 天津大学 谐振器及其制造方法
CN104124938A (zh) * 2014-07-18 2014-10-29 天津大学 谐振器以及谐振器的谐振频率调控方法
US20170063339A1 (en) * 2015-08-25 2017-03-02 Avago Technologies General Ip (Singapore) Pte. Ltd. Surface acoustic wave (saw) resonator

Patent Citations (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN1794572A (zh) * 2004-12-22 2006-06-28 安捷伦科技有限公司 用选择性金属蚀刻提高声共振器的性能
US20120091862A1 (en) * 2010-10-15 2012-04-19 Epcos Ag Electrode, Microacoustic Component and Production Method for an Electrode
CN102075161A (zh) * 2011-01-20 2011-05-25 张�浩 声波器件及其制作方法
CN103296993A (zh) * 2013-04-11 2013-09-11 天津大学 谐振器及其制造方法
CN104124938A (zh) * 2014-07-18 2014-10-29 天津大学 谐振器以及谐振器的谐振频率调控方法
US20170063339A1 (en) * 2015-08-25 2017-03-02 Avago Technologies General Ip (Singapore) Pte. Ltd. Surface acoustic wave (saw) resonator

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