JP2005321257A - Capacitance type pressure sensor - Google Patents

Capacitance type pressure sensor Download PDF

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JP2005321257A
JP2005321257A JP2004138397A JP2004138397A JP2005321257A JP 2005321257 A JP2005321257 A JP 2005321257A JP 2004138397 A JP2004138397 A JP 2004138397A JP 2004138397 A JP2004138397 A JP 2004138397A JP 2005321257 A JP2005321257 A JP 2005321257A
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fixed electrode
gap
pressure sensor
electrode
diaphragm
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Manabu Tamura
学 田村
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Alps Alpine Co Ltd
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Alps Electric Co Ltd
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Abstract

<P>PROBLEM TO BE SOLVED: To provide a capacitance type pressure sensor capable of detecting highly accurately a volume change in a wide pressure range from a low pressure to a high pressure. <P>SOLUTION: In this capacitance type pressure sensor, one substrate 2 where a movable electrode 3 comprising a diaphragm deformed elastically by a pressure and the other substrate 5 where a fixed electrode 4 is formed are arranged oppositely through a gap 6 provided between the movable electrode 3 and the fixed electrode 4, and a capacitance change between the movable electrode 3 and the fixed electrode 4 is detected. In the capacitance type pressure sensor 1, the fixed electrode 4 is formed so that the gap 6 at the center part of the fixed electrode 4 becomes narrower than the gap 6 at the peripheral part of the fixed electrode 4, and an insulating film 12 for covering the surface on the gap side of the fixed electrode 4 and/or the movable electrode 3 is formed. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

本発明は、一方の基板に形成された固定電極部と、他方の基板に形成されたダイヤフラム部との間にギャップが設けられた静電容量型圧力センサに関するものである。   The present invention relates to a capacitance type pressure sensor in which a gap is provided between a fixed electrode portion formed on one substrate and a diaphragm portion formed on the other substrate.

静電容量型圧力センサは、小型でしかも構造が単純であることから、最近になって様々な分野において急速に普及している。
図８に、従来の静電容量型圧力センサを示す。従来の静電容量型圧力センサ１０１は、図８に示すように、Ｓｉ基板１０２の一部を薄くして形成されたダイヤフラム１０３と、このダイヤフラム１０３に対向配置された固定電極１０４と、この固定電極１０４のダイヤフラム１０３側表面の一部に形成された凸状絶縁膜１１２と、固定電極１０４及びＳｉ基板１０２を支持する支持基板１０５とを主体として構成されている。固定電極１０４及び凸状絶縁膜１１２と、ダイヤフラム１０３との間にはギャップ１０６が設けられており、このギャップ１０６が誘電体となって一種の静電容量が形成されている（例えば、特許文献１参照）。
Ｓｉ基板１０２の上面には電極パッド（図示略）が形成され、この電極パッドにワイヤ（図示略）が接続されており、固定電極１０４には支持基板１０５をくぐって形成された取出電極（図示略）が接続されており、この取出電極にワイヤ（図示略）が接続されている。 Capacitance-type pressure sensors are small in size and simple in structure, and have recently become widespread in various fields.
FIG. 8 shows a conventional capacitive pressure sensor. As shown in FIG. 8, a conventional capacitive pressure sensor 101 includes a diaphragm 103 formed by thinning a part of a Si substrate 102, a fixed electrode 104 disposed opposite to the diaphragm 103, and a fixed electrode. The electrode 104 is mainly composed of a convex insulating film 112 formed on a part of the surface on the diaphragm 103 side and a support substrate 105 that supports the fixed electrode 104 and the Si substrate 102. A gap 106 is provided between the fixed electrode 104 and the convex insulating film 112 and the diaphragm 103, and this gap 106 serves as a dielectric to form a kind of capacitance (for example, Patent Documents). 1).
An electrode pad (not shown) is formed on the upper surface of the Si substrate 102, a wire (not shown) is connected to the electrode pad, and an extraction electrode (not shown) formed through the support substrate 105 through the fixed electrode 104. (Not shown) is connected, and a wire (not shown) is connected to the extraction electrode.

この静電容量型圧力センサ１０１では、流体の圧力変化に対応してダイヤフラム１０３が弾性変形して撓むことによってギャップの幅が変動し、このギャップ幅の変動を静電容量の変化で捉えて圧力を検知できるようになっているものである。詳しくは、流体の圧力が高くなると、まずダイヤフラム１０３は撓んで凸状絶縁膜１１２に接触した状態となる。さらにダイヤフラム１０３が撓むと、図８の点線Ａで示すように絶縁膜１１２との接触部を支点とし、この支点の両側でそれぞれ撓むことで固定電極１０４とのギャップ幅が変化して、容量変化が生じる。
特開２００２−３１８１６６号公報 In this capacitive pressure sensor 101, the width of the gap varies as the diaphragm 103 is elastically deformed and bent in response to a change in the pressure of the fluid, and the variation in the gap width is captured by a change in the capacitance. The pressure can be detected. Specifically, when the fluid pressure increases, the diaphragm 103 first bends and comes into contact with the convex insulating film 112. Further, when the diaphragm 103 is bent, as shown by a dotted line A in FIG. 8, the contact portion with the insulating film 112 is used as a fulcrum, and the gap width with the fixed electrode 104 is changed by bending at both sides of the fulcrum. Change occurs.
JP 2002-318166 A

しかしながら従来の静電容量型圧力センサにおいては、高圧力側ではダイヤフラム１０３が絶縁膜１１２との接触部の両側でそれぞれ撓んで固定電極１０４とのギャップが狭くなるため圧力に対する容量変化（感度）が大きいが、低圧力側ではダイヤフラム１０３と固定電極１０４の距離が遠い（例えば、ダイヤフラム１０３が絶縁膜１１２に接触しているだけの状態）ために、圧力に対する容量変化（感度）が小さいという問題があった。   However, in the conventional capacitive pressure sensor, on the high pressure side, the diaphragm 103 bends on both sides of the contact portion with the insulating film 112 and the gap with the fixed electrode 104 is narrowed. Although large, on the low pressure side, the distance between the diaphragm 103 and the fixed electrode 104 is long (for example, the state in which the diaphragm 103 is only in contact with the insulating film 112), so that there is a problem that the capacitance change (sensitivity) with respect to pressure is small. there were.

本発明は上記事情に鑑みてなされたもので、低圧から高圧までの広い圧力範囲にわたって容量変化を高感度で検出できる静電容量型圧力センサの提供を目的とする。   The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a capacitive pressure sensor that can detect a change in capacitance with high sensitivity over a wide pressure range from low pressure to high pressure.

本発明の静電容量型圧力センサは、圧力によって弾性変形するダイヤフラムからなる可動電極が形成された一方の基板と、固定電極が形成された他方の基板とが上記可動電極と固定電極の間に設けられたギャップを介して対向配置され、上記可動電極と固定電極との間の静電容量の変化を検出する静電容量型圧力センサであって、
上記固定電極は、該固定電極の中心部における上記ギャップが、上記固定電極の周縁部における上記ギャップより狭くなるような形状とされ、
上記固定電極及び／又は可動電極のギャップ側の表面を覆う絶縁膜が形成されたことを特徴とする。 The capacitance-type pressure sensor of the present invention includes a substrate on which a movable electrode made of a diaphragm that is elastically deformed by pressure and a substrate on which a fixed electrode is formed between the movable electrode and the fixed electrode. A capacitance type pressure sensor that is arranged to face each other through a provided gap and detects a change in capacitance between the movable electrode and the fixed electrode,
The fixed electrode is shaped such that the gap at the center of the fixed electrode is narrower than the gap at the periphery of the fixed electrode,
An insulating film is formed to cover the gap side surface of the fixed electrode and / or the movable electrode.

本発明の静電容量型圧力センサでは、上記固定電極の中心部と上記可動電極間のギャップが、上記固定電極の周縁部と上記可動電極間のギャップより狭くされたことにより、低圧側で圧力が変化した場合はギャップが狭いところで可動電極と固定電極のギャップ幅が変化することとなり、低圧力側での容量変化を高感度で検出できる。また、圧力がさらに高くなると、上記固定電極の中心部と上記可動電極とが接触両側で固定電極と可動電極間のギャップ幅が変化するため、高圧力側の容量変化を高感度で検出できる。従って、本発明の静電容量型圧力センサでは、低圧から高圧までの広い圧力範囲にわたって容量変化を高感度で検出することができる。   In the capacitance type pressure sensor of the present invention, the gap between the center portion of the fixed electrode and the movable electrode is narrower than the gap between the peripheral portion of the fixed electrode and the movable electrode. When the gap changes, the gap width between the movable electrode and the fixed electrode changes when the gap is narrow, and the capacitance change on the low pressure side can be detected with high sensitivity. Further, when the pressure is further increased, the gap width between the fixed electrode and the movable electrode changes on both sides of contact between the central portion of the fixed electrode and the movable electrode, so that the capacitance change on the high pressure side can be detected with high sensitivity. Therefore, the capacitance type pressure sensor of the present invention can detect a change in capacitance with high sensitivity over a wide pressure range from low pressure to high pressure.

また、上記構成の本発明の静電容量型圧力センサにおいて、上記ギャップの縦断面は、上記固定電極の周縁部から中心部にかけて階段状に狭くなる形状であってもよい。   In the capacitive pressure sensor of the present invention having the above-described configuration, the vertical cross section of the gap may have a stepwise narrowing shape from the periphery to the center of the fixed electrode.

また、上記いずれかの構成の本発明の静電容量型圧力センサにおいて、上記固定電極の形状が凸字状であることが製造し易い点で好ましい。   Moreover, in the capacitance type pressure sensor of the present invention having any one of the above structures, the shape of the fixed electrode is preferably a convex shape because it is easy to manufacture.

本発明によれば、低圧から高圧までの広い圧力範囲にわたって容量変化を高感度で検出できる静電容量型圧力センサを提供できる。   According to the present invention, it is possible to provide a capacitive pressure sensor that can detect a change in capacitance with high sensitivity over a wide pressure range from low pressure to high pressure.

次に図面を用いて本発明の実施の形態を詳細に説明する。
なお、本発明は以下に説明する実施の形態に限定されるものではないことは勿論であるとともに、以下の図面においては各構成部分の縮尺について図面に表記することが容易となるように構成部分毎に縮尺を変えて記載している。 Next, embodiments of the present invention will be described in detail with reference to the drawings.
The present invention is of course not limited to the embodiments described below, and in the following drawings, the constituent parts are shown so that the scale of each constituent part can be easily shown in the drawings. The scale is changed every time.

図１は、本発明の実施形態の静電容量型圧力センサの概略構成を示す断面図である。
本実施形態の静電容量型圧力センサ１は、シリコン基板（一方の基板）２の一部を薄くして形成された可動電極としてのダイヤフラム３と、このダイヤフラム３に対向配置された固定電極４と、固定電極４及びシリコン基板２を支持する支持基板（他方の基板）５とを主体として構成されている。
ダイヤフラム３と固定電極４との間にはギャップ６が設けられており、このギャップ６が誘電体となって一種の静電容量が形成されている。
支持基板５のシリコン基板２側の表面には、固定電極４を覆うように絶縁膜１２が形成されている。従って、この固定電極４のギャップ側の表面は絶縁膜１２が形成されている。絶縁膜１２の材質は、シリコン酸化膜や、シリコン窒化膜などが用いられ、また、厚みは０．０５μｍ〜０．２μｍ程度とされる。
この静電容量型圧力センサ１は、流体の圧力変化に対応してダイヤフラム３が弾性変形して撓むことによってギャップ幅が変動し、このギャップ幅の変動を静電容量の変化で捉えて圧力を検知できるものである。 FIG. 1 is a cross-sectional view showing a schematic configuration of a capacitive pressure sensor according to an embodiment of the present invention.
A capacitive pressure sensor 1 according to this embodiment includes a diaphragm 3 as a movable electrode formed by thinning a part of a silicon substrate (one substrate) 2, and a fixed electrode 4 arranged to face the diaphragm 3. And a support substrate (the other substrate) 5 that supports the fixed electrode 4 and the silicon substrate 2.
A gap 6 is provided between the diaphragm 3 and the fixed electrode 4, and this gap 6 serves as a dielectric to form a kind of electrostatic capacity.
An insulating film 12 is formed on the surface of the support substrate 5 on the silicon substrate 2 side so as to cover the fixed electrode 4. Therefore, the insulating film 12 is formed on the surface of the fixed electrode 4 on the gap side. The insulating film 12 is made of a silicon oxide film, a silicon nitride film, or the like, and has a thickness of about 0.05 μm to 0.2 μm.
In this capacitive pressure sensor 1, the gap width changes due to the elastic deformation of the diaphragm 3 corresponding to a change in the pressure of the fluid, and the change in the gap width is detected by the change in the capacitance. Can be detected.

固定電極４は、該固定電極４の中心部とダイヤフラム３間のギャップ６が、固定電極４の周縁部とダイヤフラム３間のギャップ６より狭くなるような形状とされている。
固定電極４は縦断面階段状とされ、特に、本実施形態では縦断面形状が凸字とされている。
固定電極４は、第１の導電性金属膜４ａと、この第１の導電性金属膜４ａの中央部に積層された第２の導電性金属膜４ｂから構成されることで、固定電極４の中央部に第２の導電性金属膜４ｂからなる凸部が設けられている。この凸部４ｂの頂部は、平坦面を有していることが好ましい。
第１の導電性金属膜４ａの直径はダイヤフラム３の直径の６０〜９０％程度とされ、第２の導電性金属膜４ｂの直径はダイヤフラム３の直径の５〜２０％程度とされることが好ましい。
第１の導電性金属膜４ａは、Ｔｉ、Ｃｒ、Ｐｔ、Ｗ、Ａｌ合金などから構成されており、第２の導電性金属膜４ｂはＡｌ、Ｃｒ、Ｔｉ、Ｐｔなどから構成されている。第１と第の導電性金属膜４ａ、４ｂに用いる材料は、異なる材料を用いるのが、固定電極を形成する際に異なるエッチング液を用いることにより縦断面階段状に成形し易い点で好ましい。
上記のように固定電極４は縦断面階段状とされていることで、静電容量型圧力センサに流体の圧力変化がかかっていない状態のときは、上記ギャップ６の縦断面は、固定電極４の周縁部から中心部にかけて階段状に狭くなる形状となっている。 The fixed electrode 4 is shaped such that the gap 6 between the center of the fixed electrode 4 and the diaphragm 3 is narrower than the gap 6 between the peripheral edge of the fixed electrode 4 and the diaphragm 3.
The fixed electrode 4 has a vertical cross-sectional step shape, and in particular, the vertical cross-sectional shape is convex in this embodiment.
The fixed electrode 4 includes the first conductive metal film 4a and the second conductive metal film 4b laminated at the center of the first conductive metal film 4a. A convex portion made of the second conductive metal film 4b is provided in the central portion. It is preferable that the top part of this convex part 4b has a flat surface.
The diameter of the first conductive metal film 4a may be about 60 to 90% of the diameter of the diaphragm 3, and the diameter of the second conductive metal film 4b may be about 5 to 20% of the diameter of the diaphragm 3. preferable.
The first conductive metal film 4a is made of Ti, Cr, Pt, W, Al alloy or the like, and the second conductive metal film 4b is made of Al, Cr, Ti, Pt or the like. It is preferable to use different materials for the first and the first conductive metal films 4a and 4b because different etching liquids are used when forming the fixed electrodes, so that the first and second conductive metal films 4a and 4b can be easily formed into a stepped vertical section.
As described above, the fixed electrode 4 has a stepwise vertical cross section. When the capacitance pressure sensor is not subjected to a change in fluid pressure, the vertical cross section of the gap 6 is It becomes the shape which becomes narrow in a step shape from the peripheral part to the center part.

シリコン基板２の上面で、ダイヤフラム３が形成されていない部分には電極パッド（図示略）が形成されている。
支持基板５は、例えば、パイレックス（登録商標）などの耐熱ガラスから構成されている。
シリコン基板２に形成された電極パッドにワイヤ（図示略）が接続され、また、固定電極４には支持基板５をくぐって形成された取出電極（図示略）が接続され、この取出電極にワイヤ（図示略）が接続されている。 An electrode pad (not shown) is formed on the upper surface of the silicon substrate 2 where the diaphragm 3 is not formed.
The support substrate 5 is made of heat resistant glass such as Pyrex (registered trademark).
A wire (not shown) is connected to an electrode pad formed on the silicon substrate 2, and an extraction electrode (not shown) formed through the support substrate 5 is connected to the fixed electrode 4, and a wire is connected to the extraction electrode. (Not shown) is connected.

次に、本実施形態の静電容量型圧力センサ１の製造方法について説明する。
本実施形態の静電容量型圧力センサ１の製造方法は、支持基板形成工程（他方の基板形成工程）と、絶縁膜形成工程と、シリコン基板形成工程（一方の基板形成工程）と、両基板接合工程とを具備して構成されている。 Next, a manufacturing method of the capacitive pressure sensor 1 of the present embodiment will be described.
The manufacturing method of the capacitive pressure sensor 1 of this embodiment includes a supporting substrate forming step (the other substrate forming step), an insulating film forming step, a silicon substrate forming step (one substrate forming step), and both substrates. And a joining step.

（支持基板形成工程）
まず、図３のＡに示すようにパイレックス（登録商標）からなる支持基板５の表面に第１の導電性金属膜４ａを形成し、さらにこの上に第２の導電性金属膜４ｂを形成する。
次いで、図３のＢに示すように、第２の導電性金属膜４ｂ上にマスク材（図示略）を配置し、ウエット又はドライエッチングによりすることにより、中央部のみ第２の導電性金属膜４ｂを残す。
次いで、図３のＣに示すように、第１の導電性金属膜４ａ上にマスク材（図示略）を配置し、ウエット又はドライエッチングすることにより、縦断面階段状の固定電極４を形成する。
ここでの工程では例えば第１の導電性金属膜４ａをＴｉから構成した場合にはエッチャントとしてフッ酸を用い、第２の導電性金属膜４ｂをＡｌから構成した場合には、エッチャントとしてリン酸を用いる。 (Support substrate formation process)
First, as shown in FIG. 3A, a first conductive metal film 4a is formed on the surface of a support substrate 5 made of Pyrex (registered trademark), and a second conductive metal film 4b is further formed thereon. .
Next, as shown in FIG. 3B, a mask material (not shown) is disposed on the second conductive metal film 4b, and wet or dry etching is performed, so that the second conductive metal film only in the central portion. Leave 4b.
Next, as shown in FIG. 3C, a mask material (not shown) is disposed on the first conductive metal film 4a, and wet or dry etching is performed to form a fixed electrode 4 having a stepped vertical section. .
In this step, for example, when the first conductive metal film 4a is made of Ti, hydrofluoric acid is used as an etchant, and when the second conductive metal film 4b is made of Al, phosphoric acid is used as an etchant. Is used.

（絶縁膜形成工程）
図４に示すように支持基板５の表面及び固定電極４の表面に絶縁膜１２を形成する。なお、この後、絶縁膜１２を固定電極４上及び固定電極４の周辺部のみ残すようにエッチングを行ってもよい。
（シリコン基板形成工程）
まず、図５に示すようにシリコン基板２の下面側（一方の面側）にギャップを形成するための凹部２１をエッチングにより形成した後、これの両面にＳｉＯ２膜又はＳｉ３Ｎ４膜からなるマスク材（図示略）を形成し、シリコン基板２の上側（ギャップが形成される側と反対側）のＳｉＯ２膜又はＳｉ３Ｎ４膜にダイヤフラム３を形成するための開口部（図示略）を形成し、この開口部内のシリコン基板を上記ＳｉＯ２膜又はＳｉ３Ｎ４膜をマスク材として用いる異方性エッチングにより所定の深さまでエッチングして厚みを薄くして、ダイヤフラム３を形成する。 (Insulating film formation process)
As shown in FIG. 4, an insulating film 12 is formed on the surface of the support substrate 5 and the surface of the fixed electrode 4. Thereafter, the insulating film 12 may be etched so as to leave only the periphery of the fixed electrode 4 and the fixed electrode 4.
(Silicon substrate formation process)
First, as shown in FIG. 5, a recess 21 for forming a gap is formed on the lower surface side (one surface side) of the silicon substrate 2 by etching, and then a SiO 2 film or a Si 3 N 4 film is formed on both surfaces thereof. And an opening (not shown) for forming the diaphragm 3 in the SiO 2 film or Si 3 N 4 film on the upper side of the silicon substrate 2 (opposite side where the gap is formed). And the silicon substrate in the opening is etched to a predetermined depth by anisotropic etching using the SiO 2 film or the Si 3 N 4 film as a mask material to form a diaphragm 3. .

（両基板接合工程）
図４の絶縁膜形成工程で絶縁膜１２を形成した支持基板５と、図５のシリコン基板形成工程で凹部２１及び可動電極となるダイヤフラム３を形成したシリコン基板２をダイヤフラム３がギャップ６を介して固定電極４と対向するように重ねて陽極接合すると、図１に示すような静電容量型圧力センサ１が得られる。 (Both substrate bonding process)
The support substrate 5 on which the insulating film 12 is formed in the insulating film forming step of FIG. 4 and the silicon substrate 2 on which the concave portion 21 and the diaphragm 3 to be the movable electrode are formed in the silicon substrate forming step of FIG. When the anodic bonding is performed so as to face the fixed electrode 4, a capacitive pressure sensor 1 as shown in FIG. 1 is obtained.

本実施形態の静電容量型圧力センサ１は、固定電極４の中央部に第２の導電性金属膜４ｂからなる凸部が設けられているので、固定電極４の中心部とダイヤフラム３間のギャップ６が、固定電極４の周縁部とダイヤフラム３間のギャップ６より狭くされているので、低圧側で圧力が変化した場合は図１の点線Ｂで示すようにダイヤフラム３は撓んで固定電極４の中心部のギャップ幅が変化することで容量が変化するため、低圧力側での容量変化を高感度で検出できる。
圧力がさらに高くなると、図２に示すように固定電極４の中心部とダイヤフラム３との接触両側でもそれぞれ固定電極４とダイヤフラム３のギャップ幅が変化することで容量が変化するため、高圧力側の容量変化を高感度で検出できる。 In the capacitive pressure sensor 1 of the present embodiment, the convex portion made of the second conductive metal film 4 b is provided in the central portion of the fixed electrode 4, and therefore, between the central portion of the fixed electrode 4 and the diaphragm 3. Since the gap 6 is narrower than the gap 6 between the peripheral edge of the fixed electrode 4 and the diaphragm 3, when the pressure changes on the low pressure side, the diaphragm 3 bends as shown by the dotted line B in FIG. Since the capacity changes due to the change in the gap width at the center, the capacity change on the low pressure side can be detected with high sensitivity.
When the pressure is further increased, the capacitance is changed by changing the gap width between the fixed electrode 4 and the diaphragm 3 on both sides of contact between the center portion of the fixed electrode 4 and the diaphragm 3, as shown in FIG. It is possible to detect a change in capacitance with high sensitivity.

なお、上記実施形態の静電容量型圧力センサにおいては、固定電極４の中央部に凸部４ｂを設けることで縦断面形状が階段状とされた場合について説明したが、本発明の静電容量型圧力センサでは、固定電極の中心部とダイヤフラム間のギャップが、上記固定電極の周縁部と上記ダイヤフラム間のギャップより狭くなっていればよいので、固定電極は図６に示すような形状であってもよい。図６の固定電極３４は縦断面形状が弓形とされていることで、固定電極３４の中心部とダイヤフラム３間のギャップが、上記固定電極３４の周縁部と上記ダイヤフラム３間のギャップより狭くなっている。この固定電極３４の表面にも絶縁膜１２が形成されている。
また、上記実施形態においては、固定電極４のギャップ側の表面を覆うように絶縁膜１２が形成された場合について説明したが、この絶縁膜１２はダイヤフラム３のギャップ側の表面に形成されていてもよいし、固定電極４のギャップ側の表面とダイヤフラム３のギャップ側の表面の両方に形成されていてもよい。 In the capacitance type pressure sensor of the above embodiment, the case where the vertical cross-sectional shape is stepped by providing the convex portion 4b at the center of the fixed electrode 4 has been described. In the type pressure sensor, the gap between the center of the fixed electrode and the diaphragm only needs to be narrower than the gap between the peripheral edge of the fixed electrode and the diaphragm, so the fixed electrode has a shape as shown in FIG. May be. The fixed electrode 34 shown in FIG. 6 has an arcuate vertical cross-sectional shape so that the gap between the center of the fixed electrode 34 and the diaphragm 3 is narrower than the gap between the peripheral edge of the fixed electrode 34 and the diaphragm 3. ing. The insulating film 12 is also formed on the surface of the fixed electrode 34.
In the above embodiment, the case where the insulating film 12 is formed so as to cover the gap side surface of the fixed electrode 4 has been described. However, the insulating film 12 is formed on the gap side surface of the diaphragm 3. Alternatively, it may be formed on both the gap side surface of the fixed electrode 4 and the gap side surface of the diaphragm 3.

（実施例１）
パイレックス（登録商標）からなる支持基板に、厚さ０．２μｍ、径１０００μｍの第１の導電性金属膜とこれの中央部に設けた厚さ０．２μｍ、径１００μｍの第２の導電性金属膜からなる縦断面階段状の固定電極を形成し、この支持基板の表面に固定電極を覆うように厚さ０．０５μｍのシリコン酸化膜からなる絶縁膜を形成した。
次にシリコン基板に直径１２００μｍ、厚さ５０μｍのダイヤフラムと、ギャップ用の凹部を形成した。
ついで、上記絶縁膜を形成した支持基板と、上記凹部及びダイヤフラムを形成したシリコン基板をダイヤフラムがギャップを介して固定電極と対向するように重ねて陽極接合し、図１と同様の静電容量型圧力センサを作製し、実施例１とした。
実施例１の静電容量型圧力センサのギャップ幅（支持基板表面からダイヤフラムまでの距離）は、０．８μｍであった。また、固定電極の中心部とダイヤフラム間のギャップ幅は０．４μｍ、固定電極の周縁部とダイヤフラム間のギャップ幅は０．６μｍであった。 (Example 1)
A first conductive metal film having a thickness of 0.2 μm and a diameter of 1000 μm and a second conductive metal having a thickness of 0.2 μm and a diameter of 100 μm provided in the center of the support substrate made of Pyrex (registered trademark) A fixed electrode having a stepwise vertical section made of a film was formed, and an insulating film made of a silicon oxide film having a thickness of 0.05 μm was formed on the surface of the support substrate so as to cover the fixed electrode.
Next, a diaphragm having a diameter of 1200 μm and a thickness of 50 μm and a recess for a gap were formed on the silicon substrate.
Next, the support substrate on which the insulating film is formed and the silicon substrate on which the concave portion and the diaphragm are formed are overlapped and anodically bonded so that the diaphragm faces the fixed electrode through a gap, and the capacitance type similar to FIG. A pressure sensor was produced and used as Example 1.
The gap width (distance from the support substrate surface to the diaphragm) of the capacitive pressure sensor of Example 1 was 0.8 μm. The gap width between the center of the fixed electrode and the diaphragm was 0.4 μm, and the gap width between the peripheral edge of the fixed electrode and the diaphragm was 0.6 μm.

（比較例１）
パイレックス（登録商標）からなる支持基板に、厚さ０．２μｍ、径１０００μｍの固定電極を形成し、この固定電極の中央部に高さ０．２μｍ、底面の径１００μｍの円錐状絶縁膜（凸状絶縁膜）を形成した。
次にシリコン基板に直径１２００μｍ、厚さ５０μｍのダイヤフラムと、ギャップ用の凹部を形成した。
ついで、上記凸状絶縁膜を形成した支持基板と、上記凹部及びダイヤフラムを形成したシリコン基板をダイヤフラムがギャップを介して固定電極と対向するように重ねて陽極接合し、図８と同様の従来タイプの静電容量型圧力センサを作製し、比較例１とした。
比較例１の静電容量型圧力センサのギャップ幅（支持基板表面からダイヤフラムまでの距離）は、０．８μｍであった。また、凸状絶縁膜とダイヤフラム間のギャップ幅は０．４μｍ、固定電極の周縁部とダイヤフラム間のギャップ幅は０．６μｍであった。 (Comparative Example 1)
A fixed electrode having a thickness of 0.2 μm and a diameter of 1000 μm is formed on a support substrate made of Pyrex (registered trademark). The insulating film was formed.
Next, a diaphragm having a diameter of 1200 μm and a thickness of 50 μm and a recess for a gap were formed on the silicon substrate.
Next, the support substrate on which the convex insulating film is formed and the silicon substrate on which the concave portion and the diaphragm are formed are overlapped and anodically bonded so that the diaphragm faces the fixed electrode through a gap, and the conventional type similar to FIG. A capacitance type pressure sensor was manufactured as Comparative Example 1.
The gap width (distance from the support substrate surface to the diaphragm) of the capacitive pressure sensor of Comparative Example 1 was 0.8 μm. The gap width between the convex insulating film and the diaphragm was 0.4 μm, and the gap width between the peripheral edge of the fixed electrode and the diaphragm was 0.6 μm.

図７に作製した実施例１と比較例１の静電容量型圧力センサにそれぞれ０ｋＰａ〜６００ｋＰａの圧力をかけたときの圧力（ｋＰａ）と容量（ｐＦ）の関係を示す。
図７に示す結果から実施例１の静電容量型圧力センサは、圧力が同じ値であっても比較例１の静電容量型圧力センサよりも容量変化が大きく、感度が優れており、このような傾向は低圧側でも高力側でも得られていることがわかる。 FIG. 7 shows the relationship between the pressure (kPa) and the capacitance (pF) when a pressure of 0 kPa to 600 kPa is applied to the capacitive pressure sensors of Example 1 and Comparative Example 1 produced.
From the results shown in FIG. 7, the capacitance type pressure sensor of Example 1 has a larger capacitance change and higher sensitivity than the capacitance type pressure sensor of Comparative Example 1, even if the pressure is the same value. It can be seen that such a tendency is obtained on both the low pressure side and the high strength side.

本発明の実施形態の静電容量型圧力センサの概略構成を示す断面図。Sectional drawing which shows schematic structure of the capacitance-type pressure sensor of embodiment of this invention. 図１の静電容量型圧力センサの動作を説明するための断面図。Sectional drawing for demonstrating operation | movement of the electrostatic capacitance type pressure sensor of FIG. 本実施形態の静電容量型圧力センサを製造するための支持基板形成工程の説明図。Explanatory drawing of the support substrate formation process for manufacturing the electrostatic capacitance type pressure sensor of this embodiment. 本実施形態の静電容量型圧力センサを製造するための絶縁膜形成工程の説明図。Explanatory drawing of the insulating film formation process for manufacturing the electrostatic capacitance type pressure sensor of this embodiment. 本実施形態の静電容量型圧力センサを製造するためのシリコン基板形成工程の説明図。Explanatory drawing of the silicon substrate formation process for manufacturing the electrostatic capacitance type pressure sensor of this embodiment. 本発明の他の実施形態の静電容量型圧力センサの概略構成を示す断面図。Sectional drawing which shows schematic structure of the capacitive pressure sensor of other embodiment of this invention. 実施例１と比較例１の静電容量型圧力センサについて圧力と容量の関係を示すグラフ。The graph which shows the relationship between a pressure and a capacity | capacitance about the capacitance-type pressure sensor of Example 1 and Comparative Example 1. 従来の静電容量型圧力センサの例を示す断面図。Sectional drawing which shows the example of the conventional electrostatic capacitance type pressure sensor.

符号の説明Explanation of symbols

１・・・静電容量型圧力センサ、２・・・シリコン基板（一方の基板）、３・・・ダイヤフラム（可動電極）、４，３４・・・固定電極、４ａ・・・第１の導電性金属膜、４ｂ・・・第２の導電性金属膜、５・・・支持基板（他方の基板）、６・・・ギャップ、１２・・・絶縁膜   DESCRIPTION OF SYMBOLS 1 ... Capacitance type pressure sensor, 2 ... Silicon substrate (one board | substrate), 3 ... Diaphragm (movable electrode), 4, 34 ... Fixed electrode, 4a ... 1st electroconductivity Conductive metal film, 4b ... second conductive metal film, 5 ... support substrate (the other substrate), 6 ... gap, 12 ... insulating film

Claims (3)

圧力によって弾性変形するダイヤフラムからなる可動電極が形成された一方の基板と、固定電極が形成された他方の基板とが前記可動電極と固定電極の間に設けられたギャップを介して対向配置され、前記可動電極と固定電極との間の静電容量の変化を検出する静電容量型圧力センサであって、
前記固定電極は、該固定電極の中心部における前記ギャップが、前記固定電極の周縁部における前記ギャップより狭くなるような形状とされ、
前記固定電極及び／又は前記可動電極のギャップ側の表面を覆う絶縁膜が形成されたことを特徴とする静電容量型圧力センサ。 One substrate on which a movable electrode made of a diaphragm that is elastically deformed by pressure and the other substrate on which a fixed electrode is formed are arranged to face each other via a gap provided between the movable electrode and the fixed electrode, A capacitance type pressure sensor for detecting a change in capacitance between the movable electrode and the fixed electrode,
The fixed electrode is shaped such that the gap at the center of the fixed electrode is narrower than the gap at the periphery of the fixed electrode,
A capacitance type pressure sensor, wherein an insulating film is formed to cover a surface of the fixed electrode and / or the movable electrode on the gap side. 前記ギャップの縦断面は、前記固定電極の周縁部から中心部にかけて階段状に狭くなる形状であることを特徴とする請求項１記載の静電容量型圧力センサ。   The capacitive pressure sensor according to claim 1, wherein a vertical cross section of the gap has a shape that narrows in a stepped manner from a peripheral portion to a central portion of the fixed electrode. 前記固定電極の形状が凸字状であることを特徴とする請求項２に記載の静電容量型圧力センサ。   The capacitive pressure sensor according to claim 2, wherein the fixed electrode has a convex shape.
JP2004138397A 2004-05-07 2004-05-07 Capacitance type pressure sensor Pending JP2005321257A (en)

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JP2007303922A (en) * 2006-05-10 2007-11-22 Alps Electric Co Ltd Capacitive pressure sensor
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US20110040189A1 (en) * 2007-12-14 2011-02-17 Koninklijke Philips Electronics N.V. Collapsed mode operable cmut including contoured substrate
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JP2007303922A (en) * 2006-05-10 2007-11-22 Alps Electric Co Ltd Capacitive pressure sensor
US20110040189A1 (en) * 2007-12-14 2011-02-17 Koninklijke Philips Electronics N.V. Collapsed mode operable cmut including contoured substrate
JP2011506075A (en) * 2007-12-14 2011-03-03 コーニンクレッカ フィリップス エレクトロニクス エヌ ヴィ CMUT operable in collapse mode with contoured substrate
US8787116B2 (en) 2007-12-14 2014-07-22 Koninklijke Philips N.V. Collapsed mode operable cMUT including contoured substrate
KR101181509B1 (en) 2010-04-30 2012-09-10 (주)코아칩스 Back touch type capacitive pressure sensor
JP2013104797A (en) * 2011-11-14 2013-05-30 Omron Corp Capacitance type pressure sensor and manufacturing method thereof, and input device
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KR101818315B1 (en) * 2013-03-11 2018-01-12 오므론 가부시키가이샤 Capacitive pressure sensor and input device
US20150090029A1 (en) * 2013-09-30 2015-04-02 Seiko Epson Corporation Physical quantity sensor, pressure sensor, altimeter, electronic apparatus, and moving object
CN109074186A (en) * 2016-04-08 2018-12-21 希迪普公司 Constitute multiple channels pressure sensor, containing its touch input device and utilize its pressure detection method
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