JP2012156401A - Electrostatic capacitance type device and method of manufacturing the same - Google Patents

Electrostatic capacitance type device and method of manufacturing the same Download PDF

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JP2012156401A
JP2012156401A JP2011015796A JP2011015796A JP2012156401A JP 2012156401 A JP2012156401 A JP 2012156401A JP 2011015796 A JP2011015796 A JP 2011015796A JP 2011015796 A JP2011015796 A JP 2011015796A JP 2012156401 A JP2012156401 A JP 2012156401A
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substrate
movable
fixed
silicon
metal film
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Takumi Taura
巧 田浦
Tomohiro Nakatani
友洋 中谷
Makoto Okumura
真 奥村
Kazuo Eda
和夫 江田
Koji Goto
浩嗣 後藤
Shuichi Yachi
秀一 屋地
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Panasonic Corp
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Panasonic Corp
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Priority to JP2011015796A priority Critical patent/JP2012156401A/en
Priority to PCT/JP2012/051507 priority patent/WO2012102292A1/en
Priority to TW101102866A priority patent/TW201234013A/en
Publication of JP2012156401A publication Critical patent/JP2012156401A/en
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    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01P—MEASURING LINEAR OR ANGULAR SPEED, ACCELERATION, DECELERATION, OR SHOCK; INDICATING PRESENCE, ABSENCE, OR DIRECTION, OF MOVEMENT
    • G01P15/00—Measuring acceleration; Measuring deceleration; Measuring shock, i.e. sudden change of acceleration
    • G01P15/02—Measuring acceleration; Measuring deceleration; Measuring shock, i.e. sudden change of acceleration by making use of inertia forces using solid seismic masses
    • G01P15/08—Measuring acceleration; Measuring deceleration; Measuring shock, i.e. sudden change of acceleration by making use of inertia forces using solid seismic masses with conversion into electric or magnetic values
    • G01P15/125—Measuring acceleration; Measuring deceleration; Measuring shock, i.e. sudden change of acceleration by making use of inertia forces using solid seismic masses with conversion into electric or magnetic values by capacitive pick-up
    • 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
    • B81C1/00182—Arrangements of deformable or non-deformable structures, e.g. membrane and cavity for use in a transducer
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01P—MEASURING LINEAR OR ANGULAR SPEED, ACCELERATION, DECELERATION, OR SHOCK; INDICATING PRESENCE, ABSENCE, OR DIRECTION, OF MOVEMENT
    • G01P15/00—Measuring acceleration; Measuring deceleration; Measuring shock, i.e. sudden change of acceleration
    • G01P15/02—Measuring acceleration; Measuring deceleration; Measuring shock, i.e. sudden change of acceleration by making use of inertia forces using solid seismic masses
    • G01P15/08—Measuring acceleration; Measuring deceleration; Measuring shock, i.e. sudden change of acceleration by making use of inertia forces using solid seismic masses with conversion into electric or magnetic values
    • G01P15/0802—Details
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01P—MEASURING LINEAR OR ANGULAR SPEED, ACCELERATION, DECELERATION, OR SHOCK; INDICATING PRESENCE, ABSENCE, OR DIRECTION, OF MOVEMENT
    • G01P15/00—Measuring acceleration; Measuring deceleration; Measuring shock, i.e. sudden change of acceleration
    • G01P15/02—Measuring acceleration; Measuring deceleration; Measuring shock, i.e. sudden change of acceleration by making use of inertia forces using solid seismic masses
    • G01P15/08—Measuring acceleration; Measuring deceleration; Measuring shock, i.e. sudden change of acceleration by making use of inertia forces using solid seismic masses with conversion into electric or magnetic values
    • G01P2015/0805—Measuring acceleration; Measuring deceleration; Measuring shock, i.e. sudden change of acceleration by making use of inertia forces using solid seismic masses with conversion into electric or magnetic values being provided with a particular type of spring-mass-system for defining the displacement of a seismic mass due to an external acceleration
    • G01P2015/0822—Measuring acceleration; Measuring deceleration; Measuring shock, i.e. sudden change of acceleration by making use of inertia forces using solid seismic masses with conversion into electric or magnetic values being provided with a particular type of spring-mass-system for defining the displacement of a seismic mass due to an external acceleration for defining out-of-plane movement of the mass
    • G01P2015/0825—Measuring acceleration; Measuring deceleration; Measuring shock, i.e. sudden change of acceleration by making use of inertia forces using solid seismic masses with conversion into electric or magnetic values being provided with a particular type of spring-mass-system for defining the displacement of a seismic mass due to an external acceleration for defining out-of-plane movement of the mass for one single degree of freedom of movement of the mass
    • G01P2015/0831—Measuring acceleration; Measuring deceleration; Measuring shock, i.e. sudden change of acceleration by making use of inertia forces using solid seismic masses with conversion into electric or magnetic values being provided with a particular type of spring-mass-system for defining the displacement of a seismic mass due to an external acceleration for defining out-of-plane movement of the mass for one single degree of freedom of movement of the mass the mass being of the paddle type having the pivot axis between the longitudinal ends of the mass, e.g. see-saw configuration
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01P—MEASURING LINEAR OR ANGULAR SPEED, ACCELERATION, DECELERATION, OR SHOCK; INDICATING PRESENCE, ABSENCE, OR DIRECTION, OF MOVEMENT
    • G01P15/00—Measuring acceleration; Measuring deceleration; Measuring shock, i.e. sudden change of acceleration
    • G01P15/02—Measuring acceleration; Measuring deceleration; Measuring shock, i.e. sudden change of acceleration by making use of inertia forces using solid seismic masses
    • G01P15/08—Measuring acceleration; Measuring deceleration; Measuring shock, i.e. sudden change of acceleration by making use of inertia forces using solid seismic masses with conversion into electric or magnetic values
    • G01P2015/0805—Measuring acceleration; Measuring deceleration; Measuring shock, i.e. sudden change of acceleration by making use of inertia forces using solid seismic masses with conversion into electric or magnetic values being provided with a particular type of spring-mass-system for defining the displacement of a seismic mass due to an external acceleration
    • G01P2015/0845—Measuring acceleration; Measuring deceleration; Measuring shock, i.e. sudden change of acceleration by making use of inertia forces using solid seismic masses with conversion into electric or magnetic values being provided with a particular type of spring-mass-system for defining the displacement of a seismic mass due to an external acceleration using a plurality of spring-mass systems being arranged on one common planar substrate, the systems not being mechanically coupled and the sensitive direction of each system being different

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  • Engineering & Computer Science (AREA)
  • Manufacturing & Machinery (AREA)
  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Microelectronics & Electronic Packaging (AREA)
  • Pressure Sensors (AREA)
  • Micromachines (AREA)

Abstract

PROBLEM TO BE SOLVED: To provide an electrostatic capacitance type device and a method of manufacturing the same that can suppress an effect on a device characteristic.SOLUTION: Penetration silicon portions 23a, 23b, 24a, 24b which are formed so as to penetrate through a fixed side substrate 2a and be exposed from both the surfaces of the fixed side substrate 2a are set as fixed electrodes 20a, 20b, 21a, 21b, and a metal film 25 is formed on the outer exposed faces of the penetration silicon portions 23a, 23b, 24a, 24b. A metal film 26 is formed at a site other than the outer exposed faces of the penetration silicon portions 23a, 23b, 24a, 24b on the surface of the fixed side substrate 2a so as to be spaced from the metal film 25. When a movable member substrate 1 and the fixed side substrate 2a are anodically joined to each other, a potential difference is applied between the fixed side substrate 2a and the movable member substrate 1 by using the metal films 25, 26, and the penetration silicon portions 23a, 23b, 24a, 24b and the movable member substrate 1 are set to have the same potential.

Description

本発明は、静電容量式デバイスの製造方法および静電容量式デバイスに関する。   The present invention relates to a method for manufacturing a capacitive device and a capacitive device.

従来、静電容量式デバイスとして、可動電極の中央部をビームによって支持するとともに、当該ビームで支持された中央部を境に可動電極の両端側の重心位置を非対称とすることで、加速度が入力された際に可動電極を揺動させるようにしたものが知られている（例えば、特許文献１参照）。   Conventionally, as a capacitive device, the center of the movable electrode is supported by a beam, and the center of gravity on both ends of the movable electrode is asymmetrical with the center supported by the beam as the boundary, so that acceleration is input. There is known one in which a movable electrode is swung when it is applied (see, for example, Patent Document 1).

この特許文献１では、可動電極を可動体基板となるシリコン基板に形成する一方、可動電極に対向する固定電極を固定側基板となるガラス基板に形成し、両基板を陽極接合により接合している。   In Patent Document 1, a movable electrode is formed on a silicon substrate that is a movable substrate, while a fixed electrode that is opposed to the movable electrode is formed on a glass substrate that is a stationary substrate, and both substrates are joined by anodic bonding. .

ところで、両基板を陽極接合により接合する際、シリコン基板に設けられた圧接電極とガラス基板に形成された固定電極から延設された端子電極とを踏み潰して導通させることで、シリコン基板と固定電極とが同電位となるようにするのが一般的である。   By the way, when bonding both substrates by anodic bonding, the pressure contact electrode provided on the silicon substrate and the terminal electrode extending from the fixed electrode formed on the glass substrate are crushed and made conductive, thereby fixing the silicon substrate. In general, the electrode is at the same potential.

特開２０１０−２１０４１９号公報JP 2010-210419 A

しかしながら、上記従来技術のように、電極同士を踏み潰すことでシリコン基板と固定電極とが同電位となるように導通させる方法では、踏み潰しを行う接合面に酸化膜などが形成されて導通不良が生じてしまうおそれがあった。また、このような踏み潰し構造を用いると、踏み潰し部分が応力の発生起点となって構造体に応力が作用し、デバイス特性に影響を与えてしまうおそれがあった。   However, as in the above prior art, in the method in which the silicon substrate and the fixed electrode are made to have the same potential by stepping on the electrodes, an oxide film or the like is formed on the joint surface where the stepping is performed, resulting in poor conduction. Could occur. Further, when such a crushing structure is used, there is a possibility that the crushing portion serves as a starting point of stress and stress acts on the structure to affect the device characteristics.

そこで、本発明は、デバイス特性に影響を与えてしまうのを抑制することのできる静電容量式デバイスの製造方法および静電容量式デバイスを得ることを目的とする。   Then, an object of this invention is to obtain the manufacturing method of an electrostatic capacitance type device which can suppress affecting a device characteristic, and an electrostatic capacitance type device.

本発明にあっては、可動電極が形成された可動体基板と、前記可動電極に対向する固定電極が形成され、前記可動体基板に陽極接合される固定側基板と、を備える静電容量式デバイスの製造方法であって、前記固定側基板の両面に露出するようにシリコンを貫通させて形成した貫通シリコンを前記固定電極とするとともに、前記可動体基板の少なくとも前記固定側基板に陽極接合される部位をシリコンで形成し、前記貫通シリコンの外側露出面に第１の金属膜を成膜するとともに、前記固定側基板の表面における前記貫通シリコンの外側露出面以外の部位に、前記第１の金属膜と離間するように第２の金属膜を成膜し、前記可動体基板と前記固定側基板とを陽極接合する際に、前記第１の金属膜および第２の金属膜を用いて、前記固定側基板と前記可動体基板との間に電位差を設ける一方、前記貫通シリコンと前記可動体基板とが同電位となるようにしたことを主要な特徴とする。   In the present invention, a capacitive substrate comprising: a movable substrate on which a movable electrode is formed; and a fixed-side substrate on which a fixed electrode facing the movable electrode is formed and is anodically bonded to the movable substrate. A device manufacturing method, wherein a through silicon formed by penetrating silicon so as to be exposed on both surfaces of the fixed side substrate is used as the fixed electrode, and is anodically bonded to at least the fixed side substrate of the movable substrate. And forming a first metal film on the outer exposed surface of the through silicon, and forming the first metal film on a portion of the surface of the fixed substrate other than the outer exposed surface of the through silicon. A second metal film is formed so as to be separated from the metal film, and when the movable substrate and the stationary substrate are anodically bonded, the first metal film and the second metal film are used, Fixed substrate While a potential difference between said movable member substrate is mainly characterized in that said through-silicon and the movable body substrate was set to be the same potential.

本発明によれば、固定側基板と可動体基板との間に電位差を設けるとともに、貫通シリコンと可動体基板とを同電位にした状態で、可動体基板と固定側基板との陽極接合を行っている。そのため、踏み潰し構造を用いることなく陽極接合を行うことが可能となる。その結果、接合部分に酸化膜が形成されて導通不良が生じてしまうのを抑制することができる上、踏み潰し部分に応力が作用してデバイス特性に影響を与えてしまうのを抑制することができる。   According to the present invention, a potential difference is provided between the fixed substrate and the movable substrate, and anodic bonding between the movable substrate and the fixed substrate is performed with the through silicon and the movable substrate at the same potential. ing. Therefore, anodic bonding can be performed without using a stepping-down structure. As a result, it is possible to suppress the formation of an oxide film at the bonding portion, resulting in poor conduction, and to suppress the stress from acting on the squashed portion and affecting the device characteristics. it can.

また、金属膜を用いて、固定側基板と可動体基板との間に電位差を設ける一方、貫通シリコンと可動体基板とが同電位となるようにしたため、電圧の印加や同電位化をより確実に行うことができる。   In addition, a metal film is used to provide a potential difference between the fixed-side substrate and the movable substrate, while the through silicon and the movable substrate are set to the same potential. Can be done.

図１は、本発明の一実施形態にかかる静電容量式デバイスを示す分解斜視図である。FIG. 1 is an exploded perspective view showing a capacitive device according to an embodiment of the present invention. 図２は、図１に示す静電容量式デバイスの可動体基板を示し、（ａ）は可動体基板の平面図、（ｂ）は可動体基板の底面図である。2 shows a movable substrate of the capacitance type device shown in FIG. 1, wherein (a) is a plan view of the movable substrate, and (b) is a bottom view of the movable substrate. 図３は、図１に示す静電容量式デバイスの模式的な断面図である。FIG. 3 is a schematic cross-sectional view of the capacitance type device shown in FIG. 図４は、図１に示す静電容量式デバイスの製造途中を示すウエハの平面図である。FIG. 4 is a plan view of a wafer showing the manufacturing process of the capacitive device shown in FIG. 図５は、図４中I部の拡大図である。FIG. 5 is an enlarged view of a portion I in FIG. 図６は、図５中II部の拡大図である。FIG. 6 is an enlarged view of a portion II in FIG.

以下、本発明の実施形態について図面を参照しつつ詳細に説明する。以下では、静電容量式デバイスとして、加速度センサを例示する。また、錘部の可動電極が形成される側をシリコン基板の表面側と定義する。そして、シリコン基板の短手方向をＸ方向、シリコン基板の長手方向をＹ方向、シリコン基板の厚さ方向をＺ方向として説明する。   Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. Below, an acceleration sensor is illustrated as an electrostatic capacitance type device. Further, the side of the weight portion on which the movable electrode is formed is defined as the surface side of the silicon substrate. In the following description, the short direction of the silicon substrate is the X direction, the long direction of the silicon substrate is the Y direction, and the thickness direction of the silicon substrate is the Z direction.

本実施形態にかかる加速度センサＳは、可動電極４、５を有する可動体基板としてのシリコン基板１と、このシリコン基板１の表面（図１の上面）に陽極接合されて可動電極４、５に対向する固定電極２０ａ、２０ｂ、２１ａ、２１ｂが形成された固定側基板としての上部固定板２ａと、シリコン基板１の裏面（図１の下面）に接合されて閉塞板となる下部固定板２ｂとを備えている。このように、本実施形態にかかる加速度センサＳは、上部固定板２ａと下部固定板２ｂとの間にシリコン基板１が挟持されたセンサチップとして構成されている。   The acceleration sensor S according to this embodiment includes a silicon substrate 1 as a movable substrate having movable electrodes 4 and 5, and anodically bonded to the surface of the silicon substrate 1 (upper surface in FIG. 1). An upper fixing plate 2a as a fixed-side substrate on which opposed fixed electrodes 20a, 20b, 21a and 21b are formed, and a lower fixing plate 2b which is bonded to the back surface (the lower surface in FIG. 1) of the silicon substrate 1 and serves as a closing plate It has. Thus, the acceleration sensor S according to the present embodiment is configured as a sensor chip in which the silicon substrate 1 is sandwiched between the upper fixed plate 2a and the lower fixed plate 2b.

シリコン基板１は、シリコンＳＯＩ基板により形成されており、図１に示すように、２つの矩形枠３ａ、３ｂを有するフレーム３と、矩形枠２ａ、３ｂの側壁に対して隙間をあけた状態で矩形枠３ａ、３ｂに配置された矩形形状の２つの可動電極４、５とを備えている。   The silicon substrate 1 is formed of a silicon SOI substrate. As shown in FIG. 1, the frame 3 having two rectangular frames 3a and 3b and a side wall of the rectangular frames 2a and 3b are spaced from each other. Two movable electrodes 4 and 5 having a rectangular shape arranged in the rectangular frames 3a and 3b are provided.

可動電極４、５は、それぞれの側面の対向する二辺のほぼ中央が、一対のビーム６ａ、６ｂおよび７ａ、７ｂによって矩形枠３ａ、３ｂの側壁に連結されている。すなわち、一方の可動電極４がビーム６ａ、６ｂによってフレーム３に対して揺動自在に支持されるとともに、他方の可動電極５がビーム７ａ、７ｂによってフレーム３に対して揺動自在に支持されている。なお、本実施形態では、ビーム６ａ、６ｂおよびビーム７ａ、７ｂは、シリコン基板１のＺ方向（厚さ方向）に対して上部固定板２ａに対向した表面側（図１の上面側）に偏って配置されている。また、可動電極４、５の表裏面には、可動電極４、５が固定電極２０ａ、２０ｂ、２１ａ、２１ｂや後述する付着防止膜２８，２９に直接衝突するのを防止するための突起部４１，５１が突設されている。また、シリコン基板１のフレーム３表面には接地電極１０が形成されている。   The movable electrodes 4 and 5 are connected to the side walls of the rectangular frames 3a and 3b by the pair of beams 6a and 6b and 7a and 7b at substantially the center of two opposing sides of each side surface. That is, one movable electrode 4 is swingably supported with respect to the frame 3 by the beams 6a and 6b, and the other movable electrode 5 is swingably supported with respect to the frame 3 by the beams 7a and 7b. Yes. In this embodiment, the beams 6a and 6b and the beams 7a and 7b are biased to the surface side (upper surface side in FIG. 1) facing the upper fixing plate 2a with respect to the Z direction (thickness direction) of the silicon substrate 1. Are arranged. Further, on the front and back surfaces of the movable electrodes 4 and 5, the protrusions 41 for preventing the movable electrodes 4 and 5 from directly colliding with the fixed electrodes 20a, 20b, 21a and 21b and the adhesion preventing films 28 and 29 described later. , 51 are projected. A ground electrode 10 is formed on the surface of the frame 3 of the silicon substrate 1.

また、可動電極４、５は肉厚に形成されており、重りとしての機能も有している。本実施形態では、図２（ｂ）および図３に示すように、可動電極４の裏側における境界線（平面視でビーム６ａとビーム６ｂの中心を結ぶ直線）Ｍの一方側（図２（ｂ）の下側）に凹部１１が形成されており、可動電極４の重心が他方側（図２（ｂ）の上側）に片寄るようにしている。同様に、可動電極５の裏側における可動電極４に凹部１１を設けた一方側とは反対となる他方側（図２（ｂ）の上側）に凹部１１が形成されており、可動電極５の重心が一方側（図２（ｂ）の下側）に片寄るようにしている。そして、Ｘ方向もしくはＺ方向に加速度が印加された場合に、Ｘ方向およびＺ方向に印加される加速度を検出できるようにしている。   Moreover, the movable electrodes 4 and 5 are formed thick, and also have a function as a weight. In this embodiment, as shown in FIGS. 2B and 3, one side of a boundary line M (a straight line connecting the centers of the beam 6 a and the beam 6 b in a plan view) M on the back side of the movable electrode 4 (FIG. 2B ) (Lower side) is formed with a recess 11 so that the center of gravity of the movable electrode 4 is shifted to the other side (upper side in FIG. 2B). Similarly, the concave portion 11 is formed on the other side (the upper side of FIG. 2B) opposite to the one side where the concave portion 11 is provided on the movable electrode 4 on the back side of the movable electrode 5. Is shifted to one side (the lower side in FIG. 2B). When acceleration is applied in the X direction or the Z direction, the acceleration applied in the X direction and the Z direction can be detected.

上部固定板２ａは、ガラス基板により形成されており、図３に示すように、可動電極４、５の表面に対して所定間隔をあけて対向配置されている。そして、上部固定板２ａの一方の可動電極４と対向する面側には、境界線Ｍの一方側および他方側にそれぞれ固定電極２０ａ、２０ｂが設けられている。この固定電極２０ａ、２０ｂは、一方の可動電極４の表面４ａに対して所定の間隔をあけて対向配置されている。   The upper fixed plate 2a is formed of a glass substrate, and is disposed to face the surfaces of the movable electrodes 4 and 5 with a predetermined interval as shown in FIG. Then, fixed electrodes 20a and 20b are provided on one side and the other side of the boundary line M on the side of the upper fixed plate 2a facing the one movable electrode 4, respectively. The fixed electrodes 20a and 20b are arranged to face the surface 4a of one movable electrode 4 with a predetermined interval.

また、上部固定板２ａの他方の可動電極５と対向する表面側には、境界線Ｍの一方側および他方側にそれぞれ固定電極２１ａ、２１ｂが設けられており、この固定電極２１ａ、２１ｂは、他方の可動電極５の表面に対して所定間隔をあけて対向配置されている。   Further, fixed electrodes 21a and 21b are respectively provided on one side and the other side of the boundary line M on the surface side facing the other movable electrode 5 of the upper fixed plate 2a. It is arranged opposite to the surface of the other movable electrode 5 at a predetermined interval.

さらに、図１に示すように、上部固定板２ａの接地電極１０と対向する位置には、スルーホール２２ａが形成されており、このスルーホール２２ａを介して接地電極１０を外部に露出、配線させることで、接地電極１０の電位、すなわち、可動電極４，５の電位を外部に取り出せるようにしている。   Further, as shown in FIG. 1, a through hole 22a is formed at a position facing the ground electrode 10 of the upper fixing plate 2a, and the ground electrode 10 is exposed and wired through the through hole 22a. Thus, the potential of the ground electrode 10, that is, the potential of the movable electrodes 4 and 5 can be taken out to the outside.

下部固定板２ｂは、ガラス基板により形成されており、図３に示すように、双方の可動電極４、５の裏面に所定間隔をあけて対向するように配置されている。そして、この下部固定板２ｂの表面には、可動電極４、５の設置領域に対応した領域に付着防止膜２８，２９がそれぞれ形成されている（図１参照）。   The lower fixed plate 2b is formed of a glass substrate, and is disposed so as to face the back surfaces of both movable electrodes 4 and 5 with a predetermined interval as shown in FIG. Then, on the surface of the lower fixed plate 2b, adhesion preventing films 28 and 29 are formed in areas corresponding to the installation areas of the movable electrodes 4 and 5, respectively (see FIG. 1).

上述した加速度センサＳは以下のようにして製造される。   The acceleration sensor S described above is manufactured as follows.

まず、図３に示すように、シリコン基板１の表面側および裏面側に、湿式エッチングやドライエッチング等により可動電極４、５が変位するための凹部３２ａ、３２ｂを形成する。また、シリコン基板１の裏面側を更にエッチングすることで、双方の可動電極４、５および凹部１１を形成する。   First, as shown in FIG. 3, recesses 32 a and 32 b for moving the movable electrodes 4 and 5 are formed on the front side and the back side of the silicon substrate 1 by wet etching, dry etching, or the like. Moreover, both the movable electrodes 4 and 5 and the recessed part 11 are formed by further etching the back surface side of the silicon substrate 1.

その後、下部固定板２ｂをシリコン基板１の裏面側に陽極接合するとともに、上部固定板２ａに、固定電極２０ａ、２０ｂ、２１ａ、２１ｂおよびスルーホール２２ａを形成しておき、この上部固定板２ａをシリコン基板１の表面側に陽極接合する。   Thereafter, the lower fixing plate 2b is anodically bonded to the back side of the silicon substrate 1, and fixed electrodes 20a, 20b, 21a, 21b and through holes 22a are formed on the upper fixing plate 2a. Anodically bonded to the surface side of the silicon substrate 1.

このように構成された加速度センサＳは、図３の矢印ｋで示す加速度が印加されると、双方の可動電極４、５がそれぞれ揺動運動し、可動電極４、５の両端側と固定電極２０ａ、２０ｂ、２１ａ、２１ｂとの間のギャップｄが変化し、それらのギャップｄ間の静電容量Ｃ１、Ｃ２、Ｃ３、Ｃ４が変化する。   In the acceleration sensor S configured as described above, when the acceleration indicated by the arrow k in FIG. 3 is applied, both the movable electrodes 4 and 5 swing, so that both end sides of the movable electrodes 4 and 5 and the fixed electrode are moved. The gap d between 20a, 20b, 21a and 21b changes, and the capacitances C1, C2, C3 and C4 between these gaps d change.

このときの静電容量Ｃは、Ｃ＝ε×Ｓ／ｄとなることが知られており（ε：誘電率、Ｓ：電極面積、ｄ：ギャップ）、この式からギャップｄが大きくなると静電容量Ｃは減少し、ギャップｄが小さくなると静電容量Ｃは増加することになる。   The capacitance C at this time is known to be C = ε × S / d (ε: dielectric constant, S: electrode area, d: gap), and the electrostatic capacity increases as the gap d increases from this equation. The capacitance C decreases, and the capacitance C increases as the gap d decreases.

本実施形態では、検出された静電容量Ｃ１、Ｃ２、Ｃ３、Ｃ４が、例えば、ＡＳＩＣで構成される演算回路に送られてＸ方向の加速度およびＺ方向の加速度が求められ、当該加速度を示すデータが出力されるようになっている。   In the present embodiment, the detected capacitances C1, C2, C3, and C4 are sent to an arithmetic circuit constituted by, for example, an ASIC, and the acceleration in the X direction and the acceleration in the Z direction are obtained to indicate the acceleration. Data is output.

ところで、本実施形態では、一方の可動電極４を備えた第１の加速度センサ単体Ｓａと、他方の可動電極５を備えた第２の加速度センサ単体Ｓｂとを同一チップ面内に配置するとともに、それぞれの加速度センサ単体Ｓａ、Ｓｂを相対的に１８０度回転した状態で配置している（図１参照）。このように、第１の加速度センサ単体Ｓａと第２の加速度センサ単体Ｓｂとを、それぞれの可動電極４および可動電極５の重心位置が境界線Ｍに対して互いに反対側に位置するように配置することで、Ｘ方向およびＺ方向の加速度を検出できるようにしている。なお、Ｘ方向およびＺ方向の加速度の向き及び大きさを求める演算処理については従来周知であるため説明を省略する。   By the way, in this embodiment, while arrange | positioning 1st acceleration sensor single-piece | unit Sa provided with one movable electrode 4 and 2nd acceleration sensor single-piece | unit Sb provided with the other movable electrode 5, in the same chip surface, Each acceleration sensor unit Sa, Sb is arranged in a state of being relatively rotated 180 degrees (see FIG. 1). In this way, the first acceleration sensor unit Sa and the second acceleration sensor unit Sb are arranged such that the center of gravity positions of the movable electrode 4 and the movable electrode 5 are opposite to the boundary line M. By doing so, the acceleration in the X direction and the Z direction can be detected. The calculation processing for obtaining the direction and magnitude of the acceleration in the X direction and the Z direction is well known in the art and will not be described.

ここで、本実施形態では、上部固定板（固定側基板）２ａとシリコン基板（可動体基板）１との間に電位差を設けるとともに、貫通シリコン２３ａ、２３ｂ、２４ａ、２４ｂとシリコン基板（可動体基板）１とを同電位にした状態で、シリコン基板（可動体基板）１と上部固定板（固定側基板）２ａとの陽極接合を行うようにしている。   Here, in this embodiment, a potential difference is provided between the upper fixed plate (fixed side substrate) 2a and the silicon substrate (movable body substrate) 1, and the through silicones 23a, 23b, 24a, 24b and the silicon substrate (movable body) are provided. With the substrate 1 being at the same potential, anodic bonding between the silicon substrate (movable substrate) 1 and the upper fixed plate (fixed side substrate) 2a is performed.

具体的には、以下のようにしてシリコン基板１と上部固定板２ａとの陽極接合を行うようにしている。   Specifically, anodic bonding between the silicon substrate 1 and the upper fixing plate 2a is performed as follows.

まず、図１および図３に示すように、上部固定板２ａの平面視で可動電極４、５と対応する部位、すなわち、上述した固定電極２０ａ、２０ｂ、２１ａ、２１ｂが配置される部位に、上部固定板２ａの表裏両面に露出するようにシリコンを貫通させて複数の貫通シリコン２３ａ、２３ｂ、２４ａ、２４ｂを形成し、この貫通シリコン２３ａ、２３ｂ、２４ａ、２４ｂの裏面側が固定電極２０ａ、２０ｂ、２１ａ、２１ｂとなるようにする。   First, as shown in FIG. 1 and FIG. 3, the portion corresponding to the movable electrodes 4, 5 in a plan view of the upper fixed plate 2 a, that is, the portion where the above-described fixed electrodes 20 a, 20 b, 21 a, 21 b are arranged, A plurality of through silicones 23a, 23b, 24a, 24b are formed by penetrating silicon so as to be exposed on both the front and back surfaces of the upper fixing plate 2a, and the back surfaces of the through silicones 23a, 23b, 24a, 24b are fixed electrodes 20a, 20b. , 21a, 21b.

このようなガラス埋込シリコン基板は、例えば、平坦なシリコン基板の表面に窪みを形成し、平坦なガラス基板にシリコン基板の窪みが形成された面を重ね合わせ、ガラス基板を加熱することでガラス基板の一部をこの窪みの中に埋め込んだ後、ガラス基板を再固化させ、フラット基板の表裏面を研磨してシリコンを除去することで形成することができる。   Such a glass-embedded silicon substrate is formed by, for example, forming a depression on the surface of a flat silicon substrate, superimposing the surface on which the depression of the silicon substrate is formed on the flat glass substrate, and heating the glass substrate to After a part of the substrate is embedded in the recess, the glass substrate can be re-solidified, and the front and back surfaces of the flat substrate can be polished to remove silicon.

そして、シリコン基板１の少なくとも上部固定板２ａに陽極接合される部位をシリコンで形成する。   Then, at least a portion of the silicon substrate 1 to be anodically bonded to the upper fixing plate 2a is formed of silicon.

本実施形態では、シリコン基板１の両面周縁部が上部固定板２ａおよび下部固定板２ｂの周縁部にそれぞれ陽極接合されるようになっている。このシリコン基板１として、本実施形態では、Ｓｉからなるシリコン活性層１ｂとＳｉからなる支持基板１ｃとの間にＳｉＯ２からなる埋込絶縁層１ａが介在するＳＯＩ基板を用いている。 In the present embodiment, both-surface peripheral portions of the silicon substrate 1 are anodically bonded to the peripheral portions of the upper fixing plate 2a and the lower fixing plate 2b, respectively. In this embodiment, an SOI substrate in which a buried insulating layer 1a made of SiO 2 is interposed between a silicon active layer 1b made of Si and a support substrate 1c made of Si is used as the silicon substrate 1.

このように、シリコン基板１としてＳＯＩ基板を用いることで、シリコン基板１の少なくとも上部固定板２ａに陽極接合される部位がシリコンで形成されることとなる。   As described above, by using an SOI substrate as the silicon substrate 1, at least a portion of the silicon substrate 1 to be anodically bonded to the upper fixing plate 2a is formed of silicon.

そして、貫通シリコン２３ａ、２３ｂ、２４ａ、２４ｂの外側露出面に第１の金属膜としてのアルミ膜２５を成膜するとともに、上部固定板２ａの外側面周縁部（上部固定板２ａの表面における貫通シリコン２３ａ、２３ｂ、２４ａ、２４ｂの外側露出面以外の部位）に、第２の金属膜としてのアルミ膜２６をアルミ膜２５と離間するように成膜する。このように、アルミ膜２５とアルミ膜２６とを互いに接触しないように成膜することで、アルミ膜２５とアルミ膜２６とが短絡してしまうのを抑制している。   Then, an aluminum film 25 as a first metal film is formed on the outer exposed surfaces of the penetrating silicons 23a, 23b, 24a, 24b, and the outer peripheral edge of the upper fixing plate 2a (the penetration on the surface of the upper fixing plate 2a). An aluminum film 26 as a second metal film is formed on the silicon 23 a, 23 b, 24 a, 24 b other than the outer exposed surface so as to be separated from the aluminum film 25. In this way, the aluminum film 25 and the aluminum film 26 are formed so as not to contact each other, thereby preventing the aluminum film 25 and the aluminum film 26 from being short-circuited.

そして、貫通シリコン２３ａ、２３ｂ、２４ａ、２４ｂをアルミ膜２５および金属配線ｗ２を介してアースするとともに、シリコン基板１の周縁部を金属配線ｗ３を介してアースすることで、貫通シリコン２３ａ、２３ｂ、２４ａ、２４ｂとシリコン基板１とが同電位となるようにする。   The through silicones 23a, 23b, 24a, and 24b are grounded through the aluminum film 25 and the metal wiring w2, and the peripheral portion of the silicon substrate 1 is grounded through the metal wiring w3. 24a, 24b and the silicon substrate 1 are set to the same potential.

そして、上部固定板２ａのシリコン基板１との接合部（周縁部）にアルミ膜２６および金属配線ｗ１を介して電圧を印加して、上部固定板（固定側基板）２ａとシリコン基板（可動体基板）１との間に電位差を設けることで、貫通シリコン２３ａ、２３ｂ、２４ａ、２４ｂとシリコン基板（可動体基板）１とを同電位にした状態で、シリコン基板（可動体基板）１と上部固定板（固定側基板）２ａとの陽極接合を行う。   Then, a voltage is applied to the joint portion (peripheral portion) of the upper fixed plate 2a with the silicon substrate 1 via the aluminum film 26 and the metal wiring w1, and the upper fixed plate (fixed side substrate) 2a and the silicon substrate (movable body). By providing a potential difference between the silicon substrate (movable substrate) 1 and the upper portion of the silicon substrate (movable substrate) 1 and the silicon substrate (movable substrate) 1 at the same potential. Anodic bonding with the fixed plate (fixed side substrate) 2a is performed.

すなわち、本実施形態では、シリコン基板（可動体基板）１と上部固定板（固定側基板）２ａとを陽極接合する際に、アルミ膜（第１および第２の金属膜）２５，２６を用いて、上部固定板（固定側基板）２ａとシリコン基板（可動体基板）１との間に電位差を設けるとともに、貫通シリコン２３ａ、２３ｂ、２４ａ、２４ｂとシリコン基板（可動体基板）１とが同電位となるようにしている。   That is, in this embodiment, when the silicon substrate (movable substrate) 1 and the upper fixed plate (fixed side substrate) 2a are anodically bonded, the aluminum films (first and second metal films) 25 and 26 are used. In addition, a potential difference is provided between the upper fixed plate (fixed side substrate) 2a and the silicon substrate (movable substrate) 1, and the through silicones 23a, 23b, 24a, 24b and the silicon substrate (movable substrate) 1 are the same. The electric potential is set.

このとき、図３に示すように、アルミ膜（上部固定板２ａの表面における貫通シリコン２３ａ、２３ｂ、２４ａ、２４ｂの外側露出面以外の部位に第１の金属膜としてのアルミ膜２５と離間するように成膜した第２の金属膜）２６と貫通シリコン２３ａ、２３ｂ、２４ａ、２４ｂとの最短距離ａを、上部固定板２ａの厚さｂよりも大きく（ａ＞ｂ）するのが好適である。   At this time, as shown in FIG. 3, the aluminum film (spaced apart from the aluminum film 25 as the first metal film in a portion other than the outer exposed surface of the through silicon vias 23a, 23b, 24a, 24b on the surface of the upper fixing plate 2a). It is preferable that the shortest distance a between the second metal film 26 formed in this way and the penetrating silicons 23a, 23b, 24a, 24b is larger than the thickness b of the upper fixing plate 2a (a> b). is there.

上部固定板２ａとシリコン基板１との接合部と、貫通シリコン２３ａ、２３ｂ、２４ａ、２４ｂの貫通部には共にガラスとシリコンの界面が生じているため、ａ＜ｂとした場合、上部固定板２ａのアルミ膜２６に電圧を印加した際に、距離が近い貫通シリコン２３ａ、２３ｂ、２４ａ、２４ｂの貫通部で接合反応が起こりやすくなってしまう。しかしながら、ａ＞ｂとすれば、貫通シリコン２３ａ、２３ｂ、２４ａ、２４ｂの貫通部で接合反応が起こってしまうのを抑制することができ、積極的に上部固定板２ａとシリコン基板１との接合部で接合反応を起こさせることができるようになる。   Since an interface between glass and silicon is generated at the junction between the upper fixing plate 2a and the silicon substrate 1 and the through portions of the through silicones 23a, 23b, 24a, and 24b, when a <b, the upper fixing plate When a voltage is applied to the aluminum film 26 of 2a, a bonding reaction is likely to occur at the through portions of the through silicones 23a, 23b, 24a, and 24b that are close to each other. However, if a> b, it is possible to suppress a bonding reaction from occurring in the through portions of the through silicones 23a, 23b, 24a, and 24b, and to actively join the upper fixing plate 2a and the silicon substrate 1. It becomes possible to cause a bonding reaction at the part.

また、本実施形態では、固定電極となる貫通シリコンを複数（本実施形態では４つ）備えており、それぞれの貫通シリコン２３ａ、２３ｂ、２４ａ、２４ｂに成膜したアルミ膜（複数の貫通シリコンの外側露出面に成膜した第１の金属膜）２５を金属配線（金属配線２７および金属配線ｗ２）によって相互に導通させている（図６参照）。   Further, in this embodiment, a plurality of through silicons (four in this embodiment) serving as fixed electrodes are provided, and an aluminum film (a plurality of through silicons formed on each through silicon 23a, 23b, 24a, 24b) is provided. The first metal film 25 formed on the outer exposed surface is electrically connected to each other by metal wiring (metal wiring 27 and metal wiring w2) (see FIG. 6).

このように、本実施形態では、複数のアルミ膜２５を金属配線（金属配線２７および金属配線ｗ２）によって相互に導通させることで、図４に示すようなウエハレベルで、シリコン基板（可動体基板）１と上部固定板（固定側基板）２ａとの陽極接合を行っている。   As described above, in the present embodiment, a plurality of aluminum films 25 are electrically connected to each other by the metal wiring (metal wiring 27 and metal wiring w2), so that the silicon substrate (movable body substrate) is obtained at the wafer level as shown in FIG. ) 1 and the upper fixing plate (fixed side substrate) 2a are anodic bonded.

以下、ウエハレベルでの陽極接合について説明する。   Hereinafter, anodic bonding at the wafer level will be described.

まず、１枚のウエハＷをエッチング等により加工することで、分断した際に上述の加速度センサＳが形成されるように可動電極４，５等を複数形成する。   First, by processing one wafer W by etching or the like, a plurality of movable electrodes 4, 5 and the like are formed so that the above-described acceleration sensor S is formed when the wafer W is divided.

次に、固定電極２０ａ、２０ｂ、２１ａ、２１ｂとなる貫通シリコン２３ａ、２３ｂ、２４ａ、２４ｂが埋め込まれたガラス基板（分断した際に上部固定板２ａとなる部材）を貫通シリコン２３ａ、２３ｂ、２４ａ、２４ｂが可動電極４，５と対向するように載置する。   Next, the glass substrate (the member that becomes the upper fixing plate 2a when divided) is embedded in the through silicones 23a, 23b, 24a, in which the through silicons 23a, 23b, 24a, 24b to be the fixed electrodes 20a, 20b, 21a, 21b are embedded. 24b face the movable electrodes 4 and 5.

次に、ガラス基板の表面にアルミ膜（複数の貫通シリコンの外側露出面に成膜した第１の金属膜）２５を成膜する。このとき、隣り合う貫通シリコン２３ａ、２３ｂのアルミ膜２５の間、および隣り合う貫通シリコン２４ａ、２４ｂのアルミ膜２５の間に、双方のアルミ膜２５を相互に導通させる金属配線２７を設けている。さらに、複数のアルミ膜２５を金属配線（金属配線２７および金属配線ｗ２）によって相互に導通させるとともに、金属配線ｗ２を介してウエハＷの外周の一部に配置されたアース電極Ｗａに導通させている。すなわち、ウエハＷ全面に亘って固定電極２０ａ、２０ｂ、２１ａ、２１ｂとなる貫通シリコン２３ａ、２３ｂ、２４ａ、２４ｂの外側露出面に成膜したアルミ膜（第１の金属膜）２５どうしが金属配線（金属配線２７および金属配線ｗ２）によって相互に導通されている。   Next, an aluminum film (first metal film formed on the outer exposed surface of the plurality of through silicon) 25 is formed on the surface of the glass substrate. At this time, a metal wiring 27 is provided between the aluminum films 25 of the adjacent through silicones 23a and 23b and between the aluminum films 25 of the adjacent through silicones 24a and 24b. . Further, the plurality of aluminum films 25 are electrically connected to each other by the metal wiring (metal wiring 27 and metal wiring w2), and are electrically connected to the ground electrode Wa disposed on a part of the outer periphery of the wafer W via the metal wiring w2. Yes. That is, the aluminum films (first metal films) 25 formed on the outer exposed surfaces of the through silicon vias 23a, 23b, 24a, and 24b that become the fixed electrodes 20a, 20b, 21a, and 21b over the entire surface of the wafer W are metal wirings. They are electrically connected to each other by (metal wiring 27 and metal wiring w2).

また、ガラス基板の表面にアルミ膜（上部固定板２ａの表面における貫通シリコン２３ａ、２３ｂ、２４ａ、２４ｂの外側露出面以外の部位に第１の金属膜としてのアルミ膜２５と離間するように成膜した第２の金属膜に相当）２６を成膜する。このアルミ膜２６は、ガラス基板表面における分断した際に加速度センサＳの周縁部となる部位に成膜される。そして、このアルミ膜２６は、ウエハＷの外周を取り囲むように配置された電圧印加電極Ｗｂに金属配線ｗ１を介して導通されている。   Further, an aluminum film is formed on the surface of the glass substrate so as to be separated from the aluminum film 25 as the first metal film in a portion other than the outer exposed surface of the through silicones 23a, 23b, 24a, 24b on the surface of the upper fixing plate 2a. 26) (corresponding to the second metal film formed). The aluminum film 26 is formed on a portion that becomes the peripheral edge of the acceleration sensor S when it is divided on the surface of the glass substrate. The aluminum film 26 is electrically connected to the voltage application electrode Wb disposed so as to surround the outer periphery of the wafer W through the metal wiring w1.

なお、アルミ膜２５，アルミ膜２６，金属配線２７，金属配線ｗ１および金属配線ｗ２は、同時に成膜してもよいし、いずれかを先に成膜するようにしてもよい。   The aluminum film 25, the aluminum film 26, the metal wiring 27, the metal wiring w1, and the metal wiring w2 may be formed at the same time, or any one of them may be formed first.

また、シリコン基板１は、上述したように、金属配線ｗ３を介してアースされている。   Further, as described above, the silicon substrate 1 is grounded via the metal wiring w3.

かかる状態で、上部固定板２ａのシリコン基板１との接合部（周縁部）に電圧印加電極Ｗｂを介して電圧を印加して、上部固定板（固定側基板）２ａとシリコン基板（可動体基板）１との間に電位差を設けることで、貫通シリコン２３ａ、２３ｂ、２４ａ、２４ｂとシリコン基板（可動体基板）１とを同電位にした状態で一括して陽極接合を行うことができる。   In this state, a voltage is applied to the joint portion (peripheral portion) of the upper fixed plate 2a with the silicon substrate 1 via the voltage application electrode Wb, and the upper fixed plate (fixed side substrate) 2a and the silicon substrate (movable substrate). ) By providing a potential difference with respect to 1, anodic bonding can be performed in a lump with the through silicones 23 a, 23 b, 24 a, 24 b and the silicon substrate (movable substrate) 1 at the same potential.

すなわち、複数のアルミ膜２５を金属配線（金属配線２７および金属配線ｗ２）によって相互に導通させることで、シリコン基板（可動体基板）１と上部固定板（固定側基板）２ａとの陽極接合をウエハレベルで行うことができる。   That is, anodic bonding of the silicon substrate (movable body substrate) 1 and the upper fixed plate (fixed side substrate) 2a is achieved by connecting a plurality of aluminum films 25 to each other through metal wiring (metal wiring 27 and metal wiring w2). It can be done at the wafer level.

なお、本実施形態では、電圧印加電極Ｗｂからアルミ膜２６に印加する電圧値を−６００Ｖに設定したものを例示したが、電圧値は陽極接合する際の条件に応じて適宜設定することが可能である。   In the present embodiment, the voltage value applied to the aluminum film 26 from the voltage application electrode Wb is exemplified as -600 V. However, the voltage value can be appropriately set according to the conditions for anodic bonding. It is.

また、下部固定板２ｂ側は固定電極や可動電極が設けられない部分であるため、シリコン基板１と下部固定板２ｂとの陽極接合は従来の方法で行うことができるが、上部固定板２ａと同様の方法で陽極接合を行ってもよい。   Since the lower fixed plate 2b is a portion where no fixed electrode or movable electrode is provided, anodic bonding between the silicon substrate 1 and the lower fixed plate 2b can be performed by a conventional method. Anodic bonding may be performed by the same method.

そして、アルミ膜２５、２６や金属配線ｗ１、ｗ２、ｗ３および金属配線２７のうち、表面に残す部分にパターニングを行ってその他の部分を除去する。   Then, the aluminum film 25, 26, the metal wirings w1, w2, w3, and the metal wiring 27 are patterned on the portions left on the surface to remove the other portions.

本来、アルミ膜２５、２６や金属配線ｗ１、ｗ２、ｗ３および金属配線２７は、陽極接合した後に除去されるものであるが、本実施形態では、アルミ膜２５を残して、後ほど施行されるワイヤボンディングのパッドとして用いるようにしている。さらに、上部固定板２ａの表面に、金属配線（金属配線２７および金属配線ｗ２）を残し、隣り合う貫通シリコン２３ａ、２３ｂのアルミ膜２５の間、および隣り合う貫通シリコン２４ａ、２４ｂのアルミ膜２５の間に、金属配線（金属配線２７および金属配線ｗ２）が形成されるようにしている。   Originally, the aluminum films 25, 26, the metal wirings w 1, w 2, w 3 and the metal wiring 27 are removed after anodic bonding. However, in this embodiment, the aluminum film 25 is left, and the wire that will be implemented later. It is used as a bonding pad. Further, the metal wiring (metal wiring 27 and metal wiring w2) is left on the surface of the upper fixing plate 2a, and the aluminum film 25 between the adjacent through silicones 23a and 23b and between the adjacent through silicones 24a and 24b. Between these, metal wiring (metal wiring 27 and metal wiring w2) is formed.

そして、ウエハレベルでの陽極接合を行った後に、個々のチップに分断することで複数の加速度センサＳが製造される。   Then, after anodic bonding at the wafer level, a plurality of acceleration sensors S are manufactured by dividing into individual chips.

こうして、可動電極４，５が形成されたシリコン基板（可動体基板）１と、可動電極４，５と対向する部位に両面が露出するようにシリコンを貫通させて形成した複数の貫通シリコン２３ａ、２３ｂ、２４ａ、２４ｂを固定電極２０ａ、２０ｂ、２１ａ、２１ｂとした上部固定板（固定側基板）２ａと、貫通シリコン２３ａ、２３ｂ、２４ａ、２４ｂの外側露出面に成膜したアルミ膜（金属膜）２５と、を備え、隣り合うアルミ膜２５の間に金属配線（金属配線２７および金属配線ｗ２）が形成されている加速度センサ（静電容量式デバイス）Ｓが形成される。   In this way, a silicon substrate (movable body substrate) 1 on which the movable electrodes 4 and 5 are formed, and a plurality of through silicones 23a formed by penetrating silicon so that both surfaces are exposed at portions facing the movable electrodes 4 and 5, The upper fixed plate (fixed side substrate) 2a having 23b, 24a, 24b as fixed electrodes 20a, 20b, 21a, 21b, and the aluminum film (metal film) formed on the outer exposed surface of the through silicones 23a, 23b, 24a, 24b ) 25, and an acceleration sensor (capacitive device) S in which metal wiring (metal wiring 27 and metal wiring w2) is formed between adjacent aluminum films 25 is formed.

なお、残されたアルミ膜２５をワイヤーボンディングパッドとして活用することで、固定電極２０ａ、２０ｂおよび固定電極２１ａ、２１ｂの電位を外部に取り出せるようになる。   By using the remaining aluminum film 25 as a wire bonding pad, the potentials of the fixed electrodes 20a and 20b and the fixed electrodes 21a and 21b can be extracted to the outside.

以上説明したように、本実施形態では、上部固定板（固定側基板）２ａとシリコン基板（可動体基板）１との間に電位差を設けるとともに、貫通シリコン２３ａ、２３ｂ、２４ａ、２４ｂとシリコン基板（可動体基板）１とを同電位にした状態で、シリコン基板（可動体基板）１と上部固定板（固定側基板）２ａとの陽極接合を行っている。そのため、踏み潰し構造を用いることなく陽極接合を行うことが可能となる。その結果、接合部分に酸化膜が形成されて導通不良が生じてしまうのを抑制することができる上、踏み潰し部分に応力が作用してデバイス特性に影響を与えてしまうのを抑制することができる。   As described above, in this embodiment, a potential difference is provided between the upper fixed plate (fixed side substrate) 2a and the silicon substrate (movable body substrate) 1, and the through silicones 23a, 23b, 24a, 24b and the silicon substrate are provided. The anodic bonding of the silicon substrate (movable substrate) 1 and the upper fixed plate (fixed side substrate) 2a is performed with the (movable substrate) 1 at the same potential. Therefore, anodic bonding can be performed without using a stepping-down structure. As a result, it is possible to suppress the formation of an oxide film at the bonding portion, resulting in poor conduction, and to suppress the stress from acting on the squashed portion and affecting the device characteristics. it can.

このように、本実施形態によれば、デバイス特性に影響を与えてしまうのを抑制することのできる加速度センサ（静電容量式デバイス）Ｓを得ることができる。   Thus, according to this embodiment, it is possible to obtain an acceleration sensor (capacitive device) S that can suppress the influence on the device characteristics.

また、アルミ膜（第１および第２の金属膜）２５、２６を用いて、上部固定板（固定側基板）２ａとシリコン基板（可動体基板）１との間に電位差を設ける一方、貫通シリコン２３ａ、２３ｂ、２４ａ、２４ｂとシリコン基板（可動体基板）１とが同電位となるようにしたため、電圧の印加や同電位化をより確実に行うことができる。また、スパッタリングや蒸着法等ＭＥＭＳデバイスに適した方法で成膜やパターニングを容易に行うことができるようになる。   In addition, a potential difference is provided between the upper fixed plate (fixed side substrate) 2a and the silicon substrate (movable substrate) 1 using the aluminum films (first and second metal films) 25 and 26, while penetrating silicon. Since 23a, 23b, 24a, 24b and the silicon substrate (movable body substrate) 1 are set to the same potential, it is possible to more reliably apply the voltage and make the same potential. In addition, film formation and patterning can be easily performed by a method suitable for a MEMS device such as sputtering or vapor deposition.

このとき、第１および第２の金属膜の材料としてアルミを用いれば、材料的にも安価なためコスト低減を達成することができる。このようなアルミ膜２５、２６によるパターニングは、ウエットエッチングおよびドライエッチング共に技術が確立されているため、加工がし易いという利点もある。特に、数μｍ程度の微細なＭＥＭＳデバイスパターン形成の際にアルミを用いるとより効果的である。   At this time, if aluminum is used as the material of the first and second metal films, the cost can be reduced because the material is inexpensive. Such patterning by the aluminum films 25 and 26 has an advantage that it is easy to process because both wet etching and dry etching techniques have been established. In particular, it is more effective to use aluminum when forming a minute MEMS device pattern of about several μm.

また、本実施形態によれば、アルミ膜２６、すなわち、上部固定板２ａの表面における貫通シリコン２３ａ、２３ｂ、２４ａ、２４ｂの外側露出面以外の部位に第１の金属膜としてのアルミ膜２５と離間するように成膜した第２の金属膜と、貫通シリコン２３ａ、２３ｂ、２４ａ、２４ｂとの最短距離ａを、上部固定板２ａの厚さｂよりも大きくしている。   Further, according to the present embodiment, the aluminum film 26, that is, the aluminum film 25 as the first metal film on the surface of the upper fixing plate 2a other than the outer exposed surface of the through silicones 23a, 23b, 24a, 24b, The shortest distance a between the second metal film formed so as to be separated from the penetrating silicons 23a, 23b, 24a, and 24b is set larger than the thickness b of the upper fixing plate 2a.

そのため、上部固定板２ａのアルミ膜２６に電圧を印加した際に、貫通シリコン２３ａ、２３ｂ、２４ａ、２４ｂの貫通部で接合反応が起こってしまうのが抑制され、積極的に上部固定板２ａとシリコン基板１との接合部で接合反応を起こさせることができるようになる。すなわち、シリコン基板１と上部固定板２ａの接合させたい部位における接合反応をより確実に起こすことができるようになる。   Therefore, when a voltage is applied to the aluminum film 26 of the upper fixing plate 2a, it is possible to suppress the occurrence of a bonding reaction in the through portions of the through silicones 23a, 23b, 24a, and 24b. It becomes possible to cause a bonding reaction at the bonding portion with the silicon substrate 1. That is, it is possible to cause a bonding reaction more reliably at a portion where the silicon substrate 1 and the upper fixing plate 2a are to be bonded.

また、本実施形態によれば、ウエハレベルで、シリコン基板（可動体基板）１と上部固定板（固定側基板）２ａとの陽極接合を行っており、ウエハＷ全面に亘って固定電極２０ａ、２０ｂ、２１ａ、２１ｂとなる貫通シリコン２３ａ、２３ｂ、２４ａ、２４ｂの外側露出面に成膜したアルミ膜（第１の金属膜）２５どうしを金属配線（金属配線２７および金属配線ｗ２）によって相互に導通している。このように、複数の加速度センサＳの陽極接合をウエハ上で一括して行うことで、デバイス特性に影響を与えてしまうのを抑制することのできる加速度センサＳの生産性をより一層向上させることができる。   Further, according to the present embodiment, the anodic bonding of the silicon substrate (movable substrate) 1 and the upper fixed plate (fixed side substrate) 2a is performed at the wafer level, and the fixed electrode 20a, The aluminum films (first metal films) 25 formed on the outer exposed surfaces of the penetrating silicons 23a, 23b, 24a, 24b to be 20b, 21a, 21b are mutually connected by metal wiring (metal wiring 27 and metal wiring w2). Conducted. As described above, by collectively performing anodic bonding of the plurality of acceleration sensors S on the wafer, it is possible to further improve the productivity of the acceleration sensor S that can suppress the influence on the device characteristics. Can do.

また、本実施形態にかかる加速度センサＳは、アルミ膜（シリコン基板１と上部固定板２ａとを陽極接合する際に、貫通シリコン２３ａ、２３ｂ、２４ａ、２４ｂとシリコン基板１とを同電位化するために貫通シリコン２３ａ、２３ｂ、２４ａ、２４ｂの外側露出面に成膜した金属膜）２５を備えている。すなわち、貫通シリコン２３ａ、２３ｂ、２４ａ、２４ｂとシリコン基板（可動体基板）１との同電位化のために成膜したアルミ膜２５をワイヤーボンディングパッドとして活用できるようにしている。   In addition, the acceleration sensor S according to the present embodiment has an aluminum film (when the silicon substrate 1 and the upper fixing plate 2a are anodically bonded, the through silicones 23a, 23b, 24a, 24b and the silicon substrate 1 are set to the same potential. For this purpose, a metal film 25 is formed on the outer exposed surface of the through silicon vias 23a, 23b, 24a, 24b. That is, the aluminum film 25 formed for the same potential of the through silicones 23a, 23b, 24a, 24b and the silicon substrate (movable substrate) 1 can be used as a wire bonding pad.

そして、隣り合うアルミ膜２５の間に金属配線（金属配線２７および金属配線ｗ２）が形成されるようにしている。   Metal wiring (metal wiring 27 and metal wiring w2) is formed between adjacent aluminum films 25.

その結果、ワイヤーボンディングのために再度金属膜などを成膜する必要がなくなり、パターニングやエッチング工程を省略することができ、工程の簡略化を図ることができる。   As a result, there is no need to form a metal film or the like again for wire bonding, patterning and etching processes can be omitted, and the process can be simplified.

この金属膜の材料としてアルミを用いれば、スパッタリングや蒸着法等ＭＥＭＳデバイスに適した方法で成膜やパターニングを容易に行うことができる上、材料的にも安価なためコスト低減を達成することができる。   If aluminum is used as the material of the metal film, film formation and patterning can be easily performed by a method suitable for a MEMS device such as sputtering or vapor deposition, and cost reduction can be achieved because the material is inexpensive. it can.

以上、本発明の好適な実施形態について説明したが、本発明は上記実施形態には限定されず、種々の変形が可能である。   The preferred embodiments of the present invention have been described above. However, the present invention is not limited to the above embodiments, and various modifications can be made.

例えば、上記実施形態では、Ｘ方向とＺ方向の２方向の加速度を検出する加速度センサを例示したが、錘部の１つをＸＹ平面内で９０度回転させて配置し、Ｙ方向を加えた３方向の加速度を検出する加速度センサとしてもよい。   For example, in the above-described embodiment, an acceleration sensor that detects acceleration in two directions of the X direction and the Z direction has been exemplified. However, one of the weight portions is arranged by being rotated 90 degrees in the XY plane, and the Y direction is added. An acceleration sensor that detects acceleration in three directions may be used.

また、上記実施形態では、静電容量式デバイスとして加速度センサを例示したが、これに限ることなく、その他の静電容量式デバイスであっても本発明を適用することができる。   Moreover, although the acceleration sensor was illustrated as an electrostatic capacitance type device in the said embodiment, this invention can be applied even if it is another electrostatic capacitance type device without being restricted to this.

また、上記実施形態では、スルーホールを介して接地電極を外部に露出、配線させることで、接地電極の電位（可動電極の電位）を外部に取り出せるようにしたものを例示したが、スルーホールに貫通シリコンを形成し、当該貫通シリコンから接地電極の電位（可動電極の電位）を外部に取り出すようにしてもよい。こうすれば、ガラス埋込シリコン基板の製造が容易になる。   In the above embodiment, the ground electrode is exposed to the outside through the through hole and wired so that the potential of the ground electrode (potential of the movable electrode) can be taken out to the outside. Through silicon may be formed, and the potential of the ground electrode (potential of the movable electrode) may be taken out from the through silicon. This facilitates the manufacture of the glass-embedded silicon substrate.

また、可動電極や固定電極その他細部のスペック（形状、大きさ、レイアウト等）も適宜に変更可能である。   Further, the specifications (shape, size, layout, etc.) of the movable electrode, the fixed electrode, and other details can be changed as appropriate.

１ シリコン基板（可動体基板）
２ａ 上部固定板（固定側基板）
４、５ 可動電極
２０ａ、２０ｂ、２１ａ、２１ｂ 固定電極
２３ａ、２３ｂ、２４ａ、２４ｂ 貫通シリコン
２５ アルミ膜（第１の金属膜：金属膜）
２６ アルミ膜（第２の金属膜）
２７ 金属配線
Ｓ 加速度センサ（静電容量式デバイス）
ａ 金属膜と貫通シリコンとの最短距離
ｂ 固体側基板の厚さ 1 Silicon substrate (movable substrate)
2a Upper fixed plate (fixed side substrate)
4, 5 Movable electrode 20a, 20b, 21a, 21b Fixed electrode 23a, 23b, 24a, 24b Through silicon 25 Aluminum film (first metal film: metal film)
26 Aluminum film (second metal film)
27 Metal wiring S Acceleration sensor (capacitance device)
a Shortest distance between metal film and through silicon b Thickness of solid side substrate

Claims (6)

可動電極が形成された可動体基板と、前記可動電極に対向する固定電極が形成され、前記可動体基板に陽極接合される固定側基板と、を備える静電容量式デバイスの製造方法であって、
前記固定側基板の両面に露出するようにシリコンを貫通させて形成した貫通シリコンを前記固定電極とするとともに、前記可動体基板の少なくとも前記固定側基板に陽極接合される部位をシリコンで形成し、
前記貫通シリコンの外側露出面に第１の金属膜を成膜するとともに、前記固定側基板の表面における前記貫通シリコンの外側露出面以外の部位に、前記第１の金属膜と離間するように第２の金属膜を成膜し、
前記可動体基板と前記固定側基板とを陽極接合する際に、前記第１の金属膜および第２の金属膜を用いて、前記固定側基板と前記可動体基板との間に電位差を設ける一方、前記貫通シリコンと前記可動体基板とが同電位となるようにしたことを特徴とする静電容量式デバイスの製造方法。 A method of manufacturing a capacitive device, comprising: a movable substrate on which a movable electrode is formed; and a fixed substrate on which a fixed electrode facing the movable electrode is formed and is anodically bonded to the movable substrate. ,
A through silicon formed by penetrating silicon so as to be exposed on both surfaces of the fixed side substrate is used as the fixed electrode, and at least a portion of the movable substrate that is anodically bonded to the fixed side substrate is formed of silicon,
A first metal film is formed on the outer exposed surface of the through silicon, and the first metal film is spaced apart from the first metal film at a portion other than the outer exposed surface of the through silicon on the surface of the fixed substrate. 2 metal films are formed,
When anodically bonding the movable substrate and the fixed substrate, a potential difference is provided between the fixed substrate and the movable substrate using the first metal film and the second metal film. A method of manufacturing a capacitance type device, wherein the through silicon and the movable substrate have the same potential. 前記第２の金属膜と前記貫通シリコンとの最短距離を、前記固定側基板の厚さよりも大きくしたことを特徴とする請求項１に記載の静電容量式デバイスの製造方法。   2. The method of manufacturing a capacitive device according to claim 1, wherein a shortest distance between the second metal film and the penetrating silicon is larger than a thickness of the fixed-side substrate. 前記第１の金属膜および第２の金属膜の材料がアルミであることを特徴とする請求項１または請求項２に記載の静電容量式デバイスの製造方法。   3. The method of manufacturing a capacitive device according to claim 1, wherein the material of the first metal film and the second metal film is aluminum. 前記可動体基板と前記固定側基板との陽極接合はウエハレベルで行われ、
ウエハ全面に亘って前記固定電極となる貫通シリコンの外側露出面に成膜した第１の金属膜どうしが金属配線によって相互に導通されていることを特徴とする請求項１〜３のうちいずれか１項に記載の静電容量式デバイスの製造方法。 The anodic bonding of the movable substrate and the fixed substrate is performed at a wafer level,
The first metal film formed on the outer exposed surface of the through silicon serving as the fixed electrode over the entire surface of the wafer is electrically connected to each other by a metal wiring. 2. A method for manufacturing a capacitance type device according to item 1. 可動電極が形成された可動体基板と、
前記可動電極と対向する部位に両面が露出するようにシリコンを貫通させて形成した複数の貫通シリコンを固定電極とした固定側基板と、
前記貫通シリコンの外側露出面に成膜した金属膜と、
を備える静電容量式デバイスであって、
隣り合う前記金属膜の間に金属配線が形成されていることを特徴とする静電容量式デバイス。 A movable substrate on which a movable electrode is formed;
A fixed-side substrate having a plurality of through silicons formed as a fixed electrode so that both surfaces are exposed at a portion facing the movable electrode; and
A metal film formed on the outer exposed surface of the through silicon;
A capacitive device comprising:
A capacitance type device, wherein a metal wiring is formed between the adjacent metal films. 前記金属膜の材料がアルミであることを特徴とする請求項５に記載の静電容量式デバイス。   The capacitive device according to claim 5, wherein a material of the metal film is aluminum.
JP2011015796A 2011-01-27 2011-01-27 Electrostatic capacitance type device and method of manufacturing the same Pending JP2012156401A (en)

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