JP2010139382A

JP2010139382A - Semiconductor pressure sensor

Info

Publication number: JP2010139382A
Application number: JP2008316121A
Authority: JP
Inventors: Fumihito Kato; 史仁加藤; Takuya Sunada; 卓也砂田; Yuichi Niimura; 雄一新村; Sachiko Mugiuda; 沙知子麦生田
Original assignee: Panasonic Electric Works Co Ltd
Current assignee: Panasonic Electric Works Co Ltd
Priority date: 2008-12-11
Filing date: 2008-12-11
Publication date: 2010-06-24

Abstract

<P>PROBLEM TO BE SOLVED: To attain reduction of the height of a semiconductor pressure sensor by forming a semiconductor substrate into a thin film. <P>SOLUTION: The semiconductor pressure sensor 1 is constituted of a first semiconductor substrate 2 which has a recess 21 formed by etching in the surface, and of a second semiconductor substrate 3 which is stuck on the surface of the first semiconductor substrate 2 and of which the portion corresponding to the recess 21 of the first semiconductor substrate 2 is made the thin film functioning as a diaphragm part 31. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

圧力の印加に伴うダイヤフラム構造の変位を検出することにより圧力を検出する半導体圧力センサに関する。 The present invention relates to a semiconductor pressure sensor that detects pressure by detecting displacement of a diaphragm structure that accompanies application of pressure.

従来、ダイヤフラム部を有するシリコン基板の裏面とガラス基板の表面とを真空雰囲気中で陽極接合することにより圧力基準室が設けられた半導体圧力センサが知られている（特許文献１参照）。
特開２００７−５７４５４号公報 2. Description of the Related Art Conventionally, a semiconductor pressure sensor is known in which a pressure reference chamber is provided by anodically bonding a back surface of a silicon substrate having a diaphragm portion and a front surface of a glass substrate in a vacuum atmosphere (see Patent Document 1).
JP 2007-57454 A

従来の半導体圧力センサでは、シリコン基板の厚さは、ダイヤフラム部を形成する際のハンドリングを考慮すると数百μｍ程度必要であり、また、ガラス基板の厚さは、圧力基準室の気密性を考慮すると数百μｍ程度必要である。このため、従来の半導体圧力センサでは半導体圧力センサの低背化が困難であった。 In the conventional semiconductor pressure sensor, the thickness of the silicon substrate needs to be about several hundred μm considering the handling when forming the diaphragm portion, and the thickness of the glass substrate takes into account the air tightness of the pressure reference chamber. Then, about several hundred μm is necessary. For this reason, it has been difficult to reduce the height of the semiconductor pressure sensor with the conventional semiconductor pressure sensor.

本発明は、上記の課題を解決するためになされたもので、低背化を実現することができる半導体圧力センサを提供することを目的としている。 The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a semiconductor pressure sensor capable of realizing a low profile.

本発明の半導体圧力センサは、上記の課題を解決するために、エッチングによって形成された凹部を表面に有する第１半導体基板と、第１半導体基板の表面に貼り合わせられ、当該第１半導体基板の凹部に対応する部分がダイヤフラム部として機能する薄膜化された第２半導体基板とで構成されていることを特徴としている。 In order to solve the above problems, a semiconductor pressure sensor of the present invention is bonded to the surface of a first semiconductor substrate having a recess formed by etching on the surface, and the surface of the first semiconductor substrate. A portion corresponding to the concave portion is constituted by a thinned second semiconductor substrate that functions as a diaphragm portion.

また、本発明の半導体圧力センサは、上記に加えて、第１半導体基板は、エッチングによって形成された凹部を表面に有する半導体層と当該半導体層の凹部以外の表面に形成された絶縁体層とを有し、第２半導体基板は、半導体層を有することを特徴としている。 Moreover, in addition to the above, the semiconductor pressure sensor of the present invention includes a first semiconductor substrate having a semiconductor layer having a recess formed by etching on the surface, and an insulator layer formed on the surface of the semiconductor layer other than the recess. And the second semiconductor substrate has a semiconductor layer.

さらに、本発明の半導体圧力センサは、上記に加えて、第１半導体基板は、エッチングによって形成された凹部を表面に有する半導体層と当該半導体層の凹部を含む表面に形成された絶縁体層を有し、第２半導体基板は、半導体層を有することを特徴としている。 Furthermore, in the semiconductor pressure sensor of the present invention, in addition to the above, the first semiconductor substrate includes a semiconductor layer having a recess formed by etching on the surface, and an insulator layer formed on the surface including the recess of the semiconductor layer. And the second semiconductor substrate has a semiconductor layer.

さらにまた、本発明の半導体圧力センサは、上記に加えて、第１半導体基板は、エッチングによって形成された凹部を表面に有する半導体層を有し、第２半導体基板は、絶縁体層と当該絶縁体層の表面に形成された半導体層とを有することを特徴としている。 Furthermore, in the semiconductor pressure sensor of the present invention, in addition to the above, the first semiconductor substrate has a semiconductor layer having a recess formed by etching on the surface, and the second semiconductor substrate includes the insulator layer and the insulating layer. And a semiconductor layer formed on the surface of the body layer.

また、本発明の半導体圧力センサは、上記に加えて、ダイヤフラム部の半導体層の裏面に不純物拡散によって形成された可動電極と、第２半導体基板の半導体層の裏面に形成された、可動電極からの電気信号を外部へ引き出すための拡散配線とを備えたことを特徴としている。 In addition to the above, the semiconductor pressure sensor of the present invention includes a movable electrode formed by impurity diffusion on the back surface of the semiconductor layer of the diaphragm portion, and a movable electrode formed on the back surface of the semiconductor layer of the second semiconductor substrate. And a diffusion wiring for extracting the electrical signal to the outside.

また、本発明の半導体圧力センサは、上記に加えて、可動電極の対極となる固定電極が第１半導体基板であることを特徴としている。 In addition to the above, the semiconductor pressure sensor of the present invention is characterized in that the fixed electrode serving as the counter electrode of the movable electrode is the first semiconductor substrate.

また、本発明の半導体圧力センサは、上記に加えて、第１半導体基板の凹部に不純物拡散によって形成された可動電極の対極となる固定電極を備えたことを特徴としている。 In addition to the above, the semiconductor pressure sensor of the present invention is characterized in that a fixed electrode serving as a counter electrode of the movable electrode formed by impurity diffusion is provided in the recess of the first semiconductor substrate.

また、本発明の半導体圧力センサは、上記に加えて、第１半導体基板の半導体層の表面に形成された、固定電極からの電気信号を外部へ引き出すための拡散配線を備えたことを特徴としている。 In addition to the above, the semiconductor pressure sensor of the present invention includes a diffusion wiring formed on the surface of the semiconductor layer of the first semiconductor substrate for extracting an electric signal from the fixed electrode to the outside. Yes.

また、本発明の半導体圧力センサは、上記に加えて、拡散配線をエッチングストップ層としたエッチングによって当該半導体圧力センサの表面に形成された出力電極用凹部と、出力電極用凹部に金属薄膜によって形成された出力電極とを備えたことを特徴としている。 Further, in addition to the above, the semiconductor pressure sensor of the present invention is formed with a recess for an output electrode formed on the surface of the semiconductor pressure sensor by etching using a diffusion wiring as an etching stop layer, and a metal thin film in the recess for the output electrode. The output electrode is provided.

本発明の半導体圧力センサによれば、第１半導体基板の厚さは、凹部を形成する際のハンドリングを考慮しても数百μｍ程度で済み、また、第２半導体基板の厚さは、圧力基準室の気密性を考慮しても数μｍ〜数十μｍ程度で済むので、従来の半導体圧力センサと比較して半分程度の低背化を実現することができ、また、すべてのプロセスが完了した後に当該半導体圧力センサの表面を研磨することでより一層の低背化を実現することができる。 According to the semiconductor pressure sensor of the present invention, the thickness of the first semiconductor substrate may be about several hundred μm even in consideration of handling when forming the recess, and the thickness of the second semiconductor substrate is the pressure. Considering the airtightness of the reference chamber, it is only about a few μm to a few tens of μm, so it is possible to achieve a half height reduction compared to conventional semiconductor pressure sensors, and all processes are completed. After that, by further polishing the surface of the semiconductor pressure sensor, it is possible to further reduce the height.

以下、図面を参照して、本発明の実施形態となる半導体圧力センサについて説明する。 Hereinafter, a semiconductor pressure sensor according to an embodiment of the present invention will be described with reference to the drawings.

［第１実施形態］
まず、図１−１及び図１−２を参照して、本発明の第１実施形態となる半導体圧力センサの構成について説明する。 [First Embodiment]
First, the configuration of the semiconductor pressure sensor according to the first embodiment of the present invention will be described with reference to FIGS. 1-1 and 1-2.

本発明の第１実施形態となる半導体圧力センサ１は、図１−１（ａ），（ｂ）に示すように、エッチングによって形成された凹部２１を表面に有する第１半導体基板２と、この第１半導体基板２の表面に貼り合わせられ、当該第１半導体基板２の凹部２１に対応する部分がダイヤフラム部３１として機能する薄膜化された第２半導体基板３とで構成され、ダイヤフラム部３１と凹部２１で囲まれた空間が圧力基準室として機能する。なお、第１半導体基板２と第２半導体基板３とを貼り合わせる方法としては、半導体基板同士を貼り合わせる方法として一般的なフュージョンボンディングや表面活性化結合などを例示することができる。 The semiconductor pressure sensor 1 according to the first embodiment of the present invention includes, as shown in FIGS. 1-1 (a) and (b), a first semiconductor substrate 2 having a concave portion 21 formed by etching on its surface, A portion bonded to the surface of the first semiconductor substrate 2 and corresponding to the concave portion 21 of the first semiconductor substrate 2 is composed of a thinned second semiconductor substrate 3 that functions as the diaphragm portion 31, and the diaphragm portion 31 and A space surrounded by the recess 21 functions as a pressure reference chamber. In addition, as a method of bonding the first semiconductor substrate 2 and the second semiconductor substrate 3, general fusion bonding, surface activation bonding, or the like can be exemplified as a method of bonding the semiconductor substrates.

第１半導体基板２は、エッチングによって形成された凹部２１を表面に有する半導体層２２（たとえば、シリコン層）と当該半導体層２２の凹部２１以外の表面に形成された絶縁体層２３（たとえば、酸化シリコン層）とを有する。第２半導体基板３は、半導体層３２と当該半導体層３２の表面（第１半導体基板２の凹部２１に対応する部分を除く。）に形成された絶縁体層３３ｂとを有する。なお、第１半導体基板２の絶縁体層２３は、必ずしも、当該半導体層２２の凹部２１以外の表面に形成されていなくともよく、図１−２（ｃ）に示すように、当該半導体層２２の凹部２１を含む表面に形成されていてもよい。 The first semiconductor substrate 2 includes a semiconductor layer 22 (for example, a silicon layer) having a recess 21 formed by etching and an insulator layer 23 (for example, an oxidation layer) formed on a surface other than the recess 21 of the semiconductor layer 22. Silicon layer). The second semiconductor substrate 3 includes a semiconductor layer 32 and an insulator layer 33b formed on the surface of the semiconductor layer 32 (excluding a portion corresponding to the recess 21 of the first semiconductor substrate 2). Note that the insulator layer 23 of the first semiconductor substrate 2 does not necessarily have to be formed on the surface of the semiconductor layer 22 other than the recess 21. As shown in FIG. It may be formed on the surface including the recess 21.

半導体圧力センサ１の表面には後述する拡散配線２４，３４をエッチングストップ層としてエッチングすることにより出力電極用凹部４，５が形成され、この出力電極用凹部４，５を含む半導体圧力センサ１の表面には金属薄膜によって出力電極６，７が形成されている。 Output electrode recesses 4 and 5 are formed on the surface of the semiconductor pressure sensor 1 by using diffusion wirings 24 and 34 described later as etching stop layers, and the semiconductor pressure sensor 1 including the output electrode recesses 4 and 5 is formed. Output electrodes 6 and 7 are formed on the surface by a metal thin film.

半導体層２２の表面の出力電極用凹部４に対応する位置には、高濃度のｐ型不純物（たとえば、ボロン）を拡散させることにより拡散配線２４が形成されている。半導体層３２の裏面のダイヤフラム部３１から出力電極用凹部５に対応する位置には、高濃度のｐ型不純物を拡散させることにより拡散配線３４が形成されている。半導体層３２のダイヤフラム部３１に対応する位置には、高濃度のｐ型不純物を拡散させることにより可動電極３５が形成され、この可動電極３５は、拡散配線３４と連続的に接続されている。 At a position corresponding to the output electrode recess 4 on the surface of the semiconductor layer 22, a diffusion wiring 24 is formed by diffusing a high-concentration p-type impurity (for example, boron). Diffusion wirings 34 are formed by diffusing high-concentration p-type impurities at positions corresponding to the output electrode recesses 5 from the diaphragm portion 31 on the back surface of the semiconductor layer 32. A movable electrode 35 is formed by diffusing a high-concentration p-type impurity at a position corresponding to the diaphragm portion 31 of the semiconductor layer 32, and the movable electrode 35 is continuously connected to the diffusion wiring 34.

以上のように構成された半導体圧力センサ１では、ダイヤフラム部３１の表面側に圧力が加わると、ダイヤフラム部３１の表面側と裏面側との間に差圧が生じることによりダイヤフラム部３１が撓み、このダイヤフラム部３１の撓みにより可動電極３５と固定電極（半導体層２２）との間の距離が変化して静電容量が変化する。このため、本発明の第１実施形態によれば、拡散配線２４，３４及び出力電極６，７を介して出力電圧の変化を検出することによりダイヤフラム部３１に印加された圧力を検出することができる。 In the semiconductor pressure sensor 1 configured as described above, when pressure is applied to the front surface side of the diaphragm portion 31, a differential pressure is generated between the front surface side and the back surface side of the diaphragm portion 31, so that the diaphragm portion 31 is bent, The distance between the movable electrode 35 and the fixed electrode (semiconductor layer 22) changes due to the bending of the diaphragm portion 31, and the capacitance changes. For this reason, according to the first embodiment of the present invention, it is possible to detect the pressure applied to the diaphragm portion 31 by detecting the change in the output voltage via the diffusion wirings 24 and 34 and the output electrodes 6 and 7. it can.

また、この半導体圧力センサ１では、たとえば、第１半導体基板２及び第２半導体基板３としてシリコン基板を用いた場合、第１半導体基板２の厚さは、凹部２１を形成する際のハンドリングを考慮しても数百μｍ程度で済み、また、第２半導体基板３の厚さは、圧力基準室の気密性を考慮しても数μｍ〜数十μｍ程度で済む。このため、本発明の第１実施形態によれば、従来の半導体圧力センサ１と比較して半分程度の低背化を実現することができ、また、すべてのプロセスが完了した後に当該半導体圧力センサ１の表面を研磨することでより一層の低背化を実現することができる。 In the semiconductor pressure sensor 1, for example, when a silicon substrate is used as the first semiconductor substrate 2 and the second semiconductor substrate 3, the thickness of the first semiconductor substrate 2 takes into account handling when forming the recess 21. Even if it is about several hundred μm, the thickness of the second semiconductor substrate 3 may be about several μm to several tens of μm even in consideration of the airtightness of the pressure reference chamber. For this reason, according to the first embodiment of the present invention, it is possible to realize a half height reduction as compared with the conventional semiconductor pressure sensor 1, and the semiconductor pressure sensor after all the processes are completed. By polishing the surface of 1, the height can be further reduced.

さらに、この半導体圧力センサ１では、ダイヤフラム部３１の可動電極３５からの電気信号が拡散配線３４により外部へ引き出される。このため、本発明の第１実施形態によれば、第１半導体基板２と第２半導体基板３の接合面に金属配線が存在せず、圧力基準室の気密性を高めることができ、また、金属配線を形成する際のウェハ汚染の心配もなく、後工程の制限が無くなる。 Further, in the semiconductor pressure sensor 1, an electrical signal from the movable electrode 35 of the diaphragm portion 31 is drawn out to the outside by the diffusion wiring 34. For this reason, according to the first embodiment of the present invention, there is no metal wiring on the joint surface between the first semiconductor substrate 2 and the second semiconductor substrate 3, and the airtightness of the pressure reference chamber can be improved, There is no concern about wafer contamination when forming the metal wiring, and there is no restriction on the post-process.

さらにまた、この半導体圧力センサ１では、第１半導体基板２の半導体層２２の表面に絶縁体層２３が形成されている。このため、本発明の第１実施形態によれば、可動電極３５から固定電極２５までの距離を絶縁体層２３の厚さにより調整することができ、半導体圧力センサ１のオフセット電圧を精度よく設定することができる。 Furthermore, in this semiconductor pressure sensor 1, an insulator layer 23 is formed on the surface of the semiconductor layer 22 of the first semiconductor substrate 2. Therefore, according to the first embodiment of the present invention, the distance from the movable electrode 35 to the fixed electrode 25 can be adjusted by the thickness of the insulator layer 23, and the offset voltage of the semiconductor pressure sensor 1 can be set with high accuracy. can do.

また、この半導体圧力センサ１は、第１半導体基板２と第２半導体基板３とで構成されている。このため、本発明の第１実施形態によれば、従来の半導体圧力センサと比較してダイシング時のブレードの摩耗を抑えることができ、半導体圧力センサ１の製造コストを低減することができる。 The semiconductor pressure sensor 1 is composed of a first semiconductor substrate 2 and a second semiconductor substrate 3. For this reason, according to 1st Embodiment of this invention, compared with the conventional semiconductor pressure sensor, the abrasion of the braid | blade at the time of dicing can be suppressed, and the manufacturing cost of the semiconductor pressure sensor 1 can be reduced.

また、この半導体圧力センサ１では、拡散配線２４，３４をエッチングストップ層としてエッチングすることにより当該半導体圧力センサ１の表面に出力電極用凹部４，５が形成されている。このため、本発明の第１実施形態によれば、出力電極６，７を容易に形成することができ、金属配線を使用せずに可動電極３５及び固定電極（半導体層２２）からの電気信号を外部へ引き出すことができる。 Further, in this semiconductor pressure sensor 1, the output electrode recesses 4 and 5 are formed on the surface of the semiconductor pressure sensor 1 by etching using the diffusion wirings 24 and 34 as an etching stop layer. Therefore, according to the first embodiment of the present invention, the output electrodes 6 and 7 can be easily formed, and electrical signals from the movable electrode 35 and the fixed electrode (semiconductor layer 22) can be used without using metal wiring. Can be pulled out.

［第２実施形態］
つぎに、図２−１及び図２−２を参照して、本発明の第２実施形態となる半導体圧力センサの構成について第１実施形態との相違点を中心に説明する。 [Second Embodiment]
Next, with reference to FIGS. 2-1 and 2-2, the configuration of the semiconductor pressure sensor according to the second embodiment of the present invention will be described focusing on the differences from the first embodiment.

本発明の第２実施形態となる半導体圧力センサ１は、第１実施形態と異なり、図２−１及び図２−２に示すように、半導体層２２の表面の凹部２１から出力電極用凹部４に対応する位置には、高濃度のｐ型不純物を拡散させることにより拡散配線２４が形成されている。また、半導体層２２の凹部２１に対応する位置には、高濃度のｐ型不純物を拡散させることにより固定電極２５が形成され、この固定電極２５は、拡散配線２４と連続的に接続されている。 The semiconductor pressure sensor 1 according to the second embodiment of the present invention is different from the first embodiment in that, as shown in FIGS. A diffusion wiring 24 is formed by diffusing a high-concentration p-type impurity at a position corresponding to. In addition, a fixed electrode 25 is formed by diffusing a high-concentration p-type impurity at a position corresponding to the recess 21 of the semiconductor layer 22, and the fixed electrode 25 is continuously connected to the diffusion wiring 24. .

以上のように構成された半導体圧力センサ１では、第１半導体基板２の固定電極２５からの電気信号が拡散配線２４により外部へ引き出される。このため、本発明の第２実施形態によれば、第１半導体基板２と第２半導体基板３の接合面に金属配線が存在せず、圧力基準室の気密性を高めることができ、また、金属配線を形成する際のウェハ汚染の心配もなく、後工程の制限が無くなる。 In the semiconductor pressure sensor 1 configured as described above, an electrical signal from the fixed electrode 25 of the first semiconductor substrate 2 is drawn to the outside by the diffusion wiring 24. For this reason, according to the second embodiment of the present invention, there is no metal wiring on the bonding surface of the first semiconductor substrate 2 and the second semiconductor substrate 3, and the airtightness of the pressure reference chamber can be improved, There is no concern about wafer contamination when forming the metal wiring, and there is no restriction on the post-process.

また、この半導体圧力センサ１では、高濃度のｐ型不純物を拡散させることにより第１半導体基板２の拡散配線２４及び固定電極２５が形成されている。このため、本発明の第２実施形態によれば、拡散プロセスにより拡散配線２４及び固定電極２５を一括して形成することができる。 In the semiconductor pressure sensor 1, the diffusion wiring 24 and the fixed electrode 25 of the first semiconductor substrate 2 are formed by diffusing high-concentration p-type impurities. For this reason, according to the second embodiment of the present invention, the diffusion wiring 24 and the fixed electrode 25 can be collectively formed by a diffusion process.

なお、上記の第１，２実施形態では、第１半導体基板２は、エッチングによって形成された凹部２１を表面に有する半導体層２２と当該半導体層２２の表面に形成された絶縁体層２３とを有し、第２半導体基板３は、半導体層３２と当該半導体層３２の表面（第１半導体基板２の凹部２１に対応する部分を除く。）に形成された絶縁体層３３ｂとを有するが、他の実施形態では、図３，４に示すように、第１半導体基板２は、エッチングによって形成された凹部２１を表面に有する半導体層２２を有し、第２半導体基板３は、絶縁体層３３ａと当該絶縁体層３３ａの表面に形成された半導体層３２と当該半導体層３２の表面（第１半導体基板２の凹部２１に対応する部分を除く。）に形成された絶縁体層３３ｂとを有してもよい。これらの場合においても、上記の第１，２実施形態と同様の効果を奏することができる。 In the first and second embodiments, the first semiconductor substrate 2 includes the semiconductor layer 22 having the recess 21 formed by etching on the surface and the insulator layer 23 formed on the surface of the semiconductor layer 22. The second semiconductor substrate 3 includes a semiconductor layer 32 and an insulator layer 33b formed on the surface of the semiconductor layer 32 (excluding a portion corresponding to the recess 21 of the first semiconductor substrate 2). In another embodiment, as shown in FIGS. 3 and 4, the first semiconductor substrate 2 includes a semiconductor layer 22 having a recess 21 formed by etching on the surface, and the second semiconductor substrate 3 includes an insulator layer. 33a, a semiconductor layer 32 formed on the surface of the insulator layer 33a, and an insulator layer 33b formed on the surface of the semiconductor layer 32 (excluding a portion corresponding to the recess 21 of the first semiconductor substrate 2). You may have. Even in these cases, the same effects as those of the first and second embodiments can be obtained.

以上、本発明者によってなされた発明を適用した実施形態について説明したが、この実施形態による本発明の開示の一部をなす記述及び図面により本発明が限定されることはない。すなわち、上記の実施形態に基づいて当業者によってなされる他の実施形態、実施例及び運用技術などはすべて本発明の範囲に含まれることを付け加えておく。 As mentioned above, although embodiment which applied the invention made | formed by this inventor was described, this invention is not limited with description and drawing which make a part of indication of this invention by this embodiment. That is, it is added that other embodiments, examples, operation techniques, and the like made by those skilled in the art based on the above embodiments are all included in the scope of the present invention.

本発明の第１実施形態となる半導体圧力センサの構成を示す（ａ）表面図、（ｂ）断面図である。It is (a) front view and (b) sectional view showing composition of a semiconductor pressure sensor used as a 1st embodiment of the present invention. 本発明の第１実施形態となる半導体圧力センサの構成を示す（ｃ）変形例の断面図である。It is sectional drawing of the modification which shows the structure of the semiconductor pressure sensor used as 1st Embodiment of this invention. 本発明の第２実施形態となる半導体圧力センサの構成を示す（ａ）表面図、（ｂ）断面図である。It is (a) front view and (b) sectional view showing composition of a semiconductor pressure sensor used as a 2nd embodiment of the present invention. 本発明の第２実施形態となる半導体圧力センサの構成を示す（ｃ）変形例の断面図である。It is sectional drawing of the (c) modification which shows the structure of the semiconductor pressure sensor used as 2nd Embodiment of this invention. 本発明の他の実施形態となる半導体圧力センサの構成を示す（ａ）表面図、（ｂ）断面図である。It is (a) front view and (b) sectional view showing composition of a semiconductor pressure sensor used as other embodiments of the present invention. 本発明の他の実施形態となる半導体圧力センサの構成を示す（ａ）表面図、（ｂ）断面図である。It is (a) front view and (b) sectional view showing composition of a semiconductor pressure sensor used as other embodiments of the present invention.

Explanation of symbols

１：半導体圧力センサ
２：第１半導体基板
２１：凹部
２２：半導体層
２３：絶縁体層
２４：拡散配線
２５：固定電極
３：第２半導体基板
３１：ダイヤフラム部
３２：半導体層
３３ａ，３３ｂ：絶縁体層
３４：拡散配線
３５：可動電極
４，５：出力電極用凹部
６，７：出力電極 1: Semiconductor pressure sensor 2: First semiconductor substrate 21: Recess 22: Semiconductor layer 23: Insulator layer 24: Diffusion wiring 25: Fixed electrode 3: Second semiconductor substrate 31: Diaphragm portion 32: Semiconductor layers 33a, 33b: Insulation Body layer 34: Diffusion wiring 35: Movable electrode 4, 5: Recess for output electrode 6, 7: Output electrode

Claims

A first semiconductor substrate having a recess formed on the surface by etching;
A semiconductor device comprising: a second semiconductor substrate which is bonded to a surface of the first semiconductor substrate, and a portion corresponding to the concave portion of the first semiconductor substrate functions as a diaphragm portion. Pressure sensor.

The first semiconductor substrate has a semiconductor layer having a recess formed by etching on its surface and an insulator layer formed on the surface of the semiconductor layer other than the recess, and the second semiconductor substrate is a semiconductor layer The semiconductor pressure sensor according to claim 1, comprising:

The first semiconductor substrate has a semiconductor layer having a recess formed by etching on the surface and an insulator layer formed on the surface of the semiconductor layer including the recess, and the second semiconductor substrate includes a semiconductor layer The semiconductor pressure sensor according to claim 1, wherein the semiconductor pressure sensor is provided.

The first semiconductor substrate has a semiconductor layer having a recess formed by etching on the surface, and the second semiconductor substrate has an insulator layer and a semiconductor layer formed on the surface of the insulator layer. The semiconductor pressure sensor according to claim 1.

A movable electrode formed by impurity diffusion on the back surface of the semiconductor layer of the diaphragm portion;
The diffusion wiring formed in the back surface of the semiconductor layer of the said 2nd semiconductor substrate for drawing out the electric signal from the said movable electrode outside is provided with any one of Claims 2-4 characterized by the above-mentioned. The semiconductor pressure sensor as described.

The semiconductor pressure sensor according to claim 5, wherein the fixed electrode serving as a counter electrode of the movable electrode is the first semiconductor substrate.

The semiconductor pressure sensor according to claim 5, further comprising a fixed electrode which is a counter electrode of the movable electrode formed by impurity diffusion in the concave portion of the first semiconductor substrate.

8. The semiconductor pressure sensor according to claim 6, further comprising a diffusion wiring formed on a surface of the semiconductor layer of the first semiconductor substrate for extracting an electrical signal from the fixed electrode to the outside.

A recess for an output electrode formed on the surface of the semiconductor pressure sensor by etching using the diffusion wiring as an etching stop layer;
The semiconductor pressure sensor according to claim 5, further comprising: an output electrode formed of a metal thin film in the recess for the output electrode.