JPH05107262A - Semiconductor acceleration sensor - Google Patents
Semiconductor acceleration sensorInfo
- Publication number
- JPH05107262A JPH05107262A JP3293684A JP29368491A JPH05107262A JP H05107262 A JPH05107262 A JP H05107262A JP 3293684 A JP3293684 A JP 3293684A JP 29368491 A JP29368491 A JP 29368491A JP H05107262 A JPH05107262 A JP H05107262A
- Authority
- JP
- Japan
- Prior art keywords
- circuit
- resistor
- bridge circuit
- diagnostic
- diagnosis
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
Classifications
-
- 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
- G01P15/12—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 alteration of electrical resistance
- G01P15/123—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 alteration of electrical resistance by piezo-resistive elements, e.g. semiconductor strain gauges
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01P—MEASURING LINEAR OR ANGULAR SPEED, ACCELERATION, DECELERATION, OR SHOCK; INDICATING PRESENCE, ABSENCE, OR DIRECTION, OF MOVEMENT
- G01P21/00—Testing or calibrating of apparatus or devices covered by the preceding groups
-
- 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
- G01P2015/0828—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 being suspended at one of its longitudinal ends
Landscapes
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Measuring Instrument Details And Bridges, And Automatic Balancing Devices (AREA)
- Pressure Sensors (AREA)
Abstract
Description
【０００１】[0001]
【産業上の利用分野】この発明は、自己診断回路を備え
たピエゾ抵抗式半導体加速度センサの構成に関する。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a structure of a piezoresistive semiconductor acceleration sensor having a self-diagnosis circuit.
【０００２】[0002]
【従来の技術】自己診断回路を備えた半導体加速度セン
サとして、例えば「ＴＯＹＯＴＡ ＡＩＲ ＢＡＧ Ｓ
ＥＮＳＯＲ」（Ｍ．Ｍｕｔｏｈ ｅｔ ａｌ、ＩＳＡＴ
Ａ ９１１２７０号 第９５頁、１９９１年）に開示さ
れたようなものがある。この半導体加速度センサは、図
５に示すように、肉薄の片持ち梁６が半導体基体の固定
部７から延びており、その先端側には質量部８が接続さ
れていて、基体主面に垂直な方向の加速度が加わると、
片持ち梁６の表面に歪みが生じ応力が発生するようにな
っている。片持ち梁６上にはピエゾ抵抗ブリッジ回路１
が形成されている。すなわちピエゾ抵抗は、例えば（１
００）シリコン基体の＜１１０＞方向に形成された梁６
上に、梁と平行に２本、垂直に２本形成されていて、応
力に対して２つの出力端子の電圧変化が逆の極性になる
ようになっている。2. Description of the Related Art As a semiconductor acceleration sensor having a self-diagnosis circuit, for example, "TOYOTA AIR BAG S" is used.
ENSOR "(M. Mutoh et al, ISAT
A 911270, page 95, 1991). In this semiconductor acceleration sensor, as shown in FIG. 5, a thin cantilever beam 6 extends from a fixed portion 7 of a semiconductor substrate, and a mass portion 8 is connected to the tip side thereof so as to be perpendicular to the main surface of the substrate. When acceleration in different directions is applied,
The surface of the cantilever 6 is distorted to generate stress. Piezoresistive bridge circuit 1 on cantilever 6
Are formed. That is, the piezo resistance is, for example, (1
00) Beam 6 formed in <110> direction of silicon substrate
Two pieces are formed on the upper side in parallel with the beam and two pieces are formed on the upper side so that the voltage changes of the two output terminals with respect to the stress have opposite polarities.
【０００３】このピエゾ抵抗ブリッジ回路１を用いた検
知および自己診断の回路は、図６のようになっており、
２はピエゾ抵抗ブリッジ回路１を駆動するための電流源
回路、３はピエゾ抵抗ブリッジ回路１の出力を増幅する
ための増幅器、４はピエゾ抵抗ブリッジ回路の出力にオ
フセットを与えるための微少電流源、５は微少電流源４
をピエゾ抵抗ブリッジ回路１の片側の出力に接続するた
めのスイッチである。増幅器３や電流源回路２、微少電
流源４など周辺回路は、図５の半導体基体の固定部７に
設けられた領域９に形成される。A detection and self-diagnosis circuit using the piezoresistive bridge circuit 1 is as shown in FIG.
2 is a current source circuit for driving the piezoresistive bridge circuit 1, 3 is an amplifier for amplifying the output of the piezoresistive bridge circuit 1, 4 is a minute current source for giving an offset to the output of the piezoresistive bridge circuit, 5 is a minute current source 4
Is a switch for connecting to the output on one side of the piezoresistive bridge circuit 1. Peripheral circuits such as the amplifier 3, the current source circuit 2, and the minute current source 4 are formed in the region 9 provided in the fixed portion 7 of the semiconductor substrate of FIG.
【０００４】半導体加速度センサ外部の制御システムか
ら診断信号が入力されると、スイッチ５がオンされ、微
少電流源４がピエゾ抵抗ブリッジ回路１に接続される。
これによりピエゾ抵抗ブリッジ回路１が擬似的に出力を
生じる形になるので、自己診断が可能となる。When a diagnostic signal is input from a control system outside the semiconductor acceleration sensor, the switch 5 is turned on and the minute current source 4 is connected to the piezoresistive bridge circuit 1.
As a result, the piezoresistive bridge circuit 1 produces a pseudo output, which enables self-diagnosis.
【０００５】他の例としてはまた、「Ａｃｃｅｌｅｒｏ
ｍｅｔｅｒ Ｓｙｓｔｅｍｓ ｗｉｔｈ Ｓｅｌｆ−ｔ
ｅｓｔａｂｌｅ Ｆｅａｔｕｒｅｓ」（ＨＥＮＲＹ
Ｖ．ＡＬＬＥＮ，ＳＴＥＰＨＥＮ Ｃ．ＴＥＲＲＹ ａ
ｎｄ ＤＩＥＤＥＲＩＫ Ｗ．ＤＥ ＢＲＵＩＮ， Ｓ
ｅｎｓｏｒｓ ａｎｄ Ａｃｔｕａｔｏｒｓ、 Ｖｏ
ｌ．２０、 第１５３〜１６１頁、１９８９年）に開示
された両持ち梁式の半導体加速度センサもある。Another example is also "Accelero.
meter Systems with Self-t
"Estable Features" (HENRY
V. ALLEN, STEPHEN C.I. TERRY a
nd DIEDERIK W.N. DE BRUIN, S
ensors and Actuators, Vo
l. 20, pp. 153-161, 1989).
【０００６】これを図７に示すと、中央の質量部１２を
挟むようにシリコン基体１０を裏面からエッチングして
複数の肉薄の梁１１が形成されていて、質量部１２を両
側から支持している。このシリコン基体１０の上下両面
には、それぞれストッパ基板１３、１４が接着されてい
る。ストッパ基板１３、１４の材料はシリコン或いはガ
ラスで、凹部１６、１７を形成して質量部１２が加速度
に応じて上下に変位可能な空間をつくっている。さらに
質量部１２と対向する部分には質量部の変位を所定限度
に制限するように、突起部１８、１９が形成されてい
る。As shown in FIG. 7, a plurality of thin beams 11 are formed by etching the silicon substrate 10 from the back side so as to sandwich the central mass portion 12, and the mass portion 12 is supported from both sides. There is. Stopper substrates 13 and 14 are adhered to the upper and lower surfaces of the silicon substrate 10, respectively. The material of the stopper substrates 13 and 14 is silicon or glass, and the recesses 16 and 17 are formed to form a space in which the mass portion 12 can be vertically displaced according to acceleration. Further, protrusions 18 and 19 are formed in a portion facing the mass portion 12 so as to limit the displacement of the mass portion to a predetermined limit.
【０００７】梁１１の表面にはブリッジ回路を構成する
ピエゾ抵抗１５が形成されていて、加速度により質量部
１２が変位し梁１１に応力が生じると、その抵抗値が変
化し加速度を検出できるようになっている。A piezoresistor 15 forming a bridge circuit is formed on the surface of the beam 11, and when the mass portion 12 is displaced by the acceleration and the stress is generated in the beam 11, the resistance value changes and the acceleration can be detected. It has become.
【０００８】この加速度センサでは、過大な加速度が加
わると質量部１２は突起部１８、１９に当接するまでは
変位するが、そこで制限されて、梁に過大応力による破
損が生じないようになっている。両持ち梁構造での通常
作動における変位量は応力の割りに小さく、この突起部
までのギャップは微少で、通常数μｍのレベルである。In this acceleration sensor, when an excessive acceleration is applied, the mass portion 12 is displaced until it comes into contact with the protrusions 18 and 19, but this is limited so that the beam will not be damaged by excessive stress. There is. The displacement amount in the normal operation in the double-supported beam structure is small relative to the stress, and the gap up to the protrusion is very small, usually on the order of several μm.
【０００９】質量部１２上には上側ストッパ基板の突起
部１８と対向して金属電極２０が形成されている。外部
から金属電極２０とストッパ基板１３の間に電圧が印加
されると、静電力により質量部１２が上方に変位し、加
速度が加わった状態を擬似的に作ることができる。これ
によりセンサの各部の機能を確認する自己診断を行うこ
とが可能となる。なお、図中２１はボンディング・パッ
ドである。その他のシリコン基体１０の表面酸化膜．配
線電極等は簡単のため省略した。A metal electrode 20 is formed on the mass portion 12 so as to face the protrusion 18 of the upper stopper substrate. When a voltage is applied between the metal electrode 20 and the stopper substrate 13 from the outside, the mass portion 12 is displaced upward by an electrostatic force, and a state in which acceleration is applied can be artificially created. This enables self-diagnosis to confirm the function of each part of the sensor. Reference numeral 21 in the drawing is a bonding pad. Other surface oxide film of silicon substrate 10. Wiring electrodes and the like are omitted for simplicity.
【００１０】[0010]
【発明が解決しようとする課題】しかしながら、上記従
来の半導体加速度センサのうち、自己診断回路として、
ピエゾ抵抗ブリッジ回路の片側の出力端子にスイッチを
介して微少電流源を接続する構成のものでは、この微少
電流源の値は、例えばピエゾ抵抗５ＫΩ、ブリッジ印加
電圧３Ｖ、フル・レンジのピエゾ抵抗の変化率を０．１
％、診断出力をフルレンジの１０％とすると、３０ｎＡ
となり、極めて小さな値にする必要がある。However, among the above-mentioned conventional semiconductor acceleration sensors, as a self-diagnosis circuit,
In a configuration in which a minute current source is connected to an output terminal on one side of a piezoresistive bridge circuit via a switch, the value of this minute current source is, for example, piezoresistor 5KΩ, bridge applied voltage 3V, full range piezoresistor. Change rate 0.1
%, Assuming that the diagnostic output is 10% of the full range, 30 nA
Therefore, the value must be extremely small.
【００１１】このような微少な電流源を実現するために
は、大きな値の抵抗と、電流を絞っていくための多段の
カレント・ミラーが必要となる。このため、微少電流源
を実現するための回路構成が複雑となり、かつ大きな面
積を占有することになるという問題があった。In order to realize such a minute current source, a resistor having a large value and a multistage current mirror for narrowing the current are required. Therefore, there is a problem that the circuit configuration for realizing the minute current source becomes complicated and occupies a large area.
【００１２】また、数μｍという狭いギャップを挟ん
で、静電力により質量部を変位させて出力をチェックす
る方式のものでは、ギャップの管理が難かしく、製造工
程も複雑である。また静電力を用いるという特殊性か
ら、サンドウィッチ構造以外の通常の加速度センサには
適用できないという問題があった。Further, in a system in which a mass portion is displaced by an electrostatic force to check an output across a narrow gap of several μm, it is difficult to manage the gap and the manufacturing process is complicated. Further, due to the peculiarity of using electrostatic force, there is a problem that it cannot be applied to ordinary acceleration sensors other than the sandwich structure.
【００１３】したがってこの発明は、上記のような従来
の問題点に着目し、自己診断のために特別の駆動電源を
設ける必要がなく、また機械構造的に精度を必要としな
い自己診断回路を備えた半導体加速度センサを提供する
ことを目的とする。Therefore, the present invention focuses on the above-mentioned conventional problems and includes a self-diagnosis circuit that does not require a special drive power source for self-diagnosis and does not require precision in terms of mechanical structure. Another object of the present invention is to provide a semiconductor acceleration sensor.
【００１４】[0014]
【課題を解決するための手段】このため本発明は、半導
体基体が固定部と質量部とこれら固定部と質量部とを接
続する薄肉の梁とに区分けされ、前記梁上にピエゾ抵抗
を有し、前記質量部の変位による前記ピエゾ抵抗の抵抗
値変化をブリッジ回路で検出する半導体加速度センサに
おいて、前記ブリッジ回路の出力端子の一端に設けられ
た診断抵抗と、診断信号を受けて前記ブリッジ回路の出
力端子と接地との間を前記診断抵抗を介して接続するス
イッチを有する自己診断回路を備え、前記診断抵抗が前
記半導体基体上に形成された薄膜抵抗で構成されるもの
とした。Therefore, according to the present invention, the semiconductor substrate is divided into a fixed portion, a mass portion, and a thin beam connecting the fixed portion and the mass portion, and a piezoresistor is provided on the beam. Then, in a semiconductor acceleration sensor that detects a resistance value change of the piezoresistor due to the displacement of the mass portion in a bridge circuit, a diagnostic resistor provided at one end of an output terminal of the bridge circuit, and the bridge circuit receiving a diagnostic signal. A self-diagnosis circuit having a switch for connecting the output terminal and the ground via the diagnostic resistor is provided, and the diagnostic resistor is composed of a thin film resistor formed on the semiconductor substrate.
【００１５】[0015]
【作用】スイッチがオフしているとき、加速度を受けて
質量部が変位すると、梁に歪み応力が生じて、ピエゾ抵
抗ブリッジ回路が歪み応力に対応したオフセットを生
じ、このオフセットを基に加速度信号が出力される。診
断信号によりスイッチがオンすると診断抵抗が接続され
る。これによりピエゾ抵抗ブリッジ回路の抵抗値が変化
し、擬似的に出力を生じる形になるので自己診断が可能
となる。When the switch is off and the mass section is displaced due to acceleration, a strain stress is generated in the beam, and the piezoresistive bridge circuit generates an offset corresponding to the strain stress. Is output. When the switch is turned on by the diagnostic signal, the diagnostic resistor is connected. As a result, the resistance value of the piezoresistive bridge circuit changes, and a pseudo output is generated, which enables self-diagnosis.
【００１６】[0016]
【実施例】図１は本発明の実施例を示す。ピエゾ抵抗ブ
リッジ回路２６にはその駆動回路としての電流源回路３
２が接続され、ピエゾ抵抗ブリッジ回路２６の出力端子
Ｐ１、Ｐ２は増幅器３３に接続されている。出力端子Ｐ
１には診断抵抗２８の一端が接続されており、診断抵抗
２８の他端は、スイッチ３４により接地される。このス
イッチ３４は診断信号を受けてオンするもので、例えば
トランジスタスイッチとすることができる。FIG. 1 shows an embodiment of the present invention. The piezoresistive bridge circuit 26 has a current source circuit 3 as its drive circuit.
2 are connected, and the output terminals P1 and P2 of the piezoresistive bridge circuit 26 are connected to the amplifier 33. Output terminal P
One end of the diagnostic resistor 28 is connected to 1, and the other end of the diagnostic resistor 28 is grounded by the switch 34. The switch 34 is turned on upon receiving a diagnostic signal, and can be, for example, a transistor switch.
【００１７】回路の主要素は、半導体基体上に図２およ
び図３に示すようにレイアウトされる。半導体基体は固
定部２２と質量部２４とこれら両者を接続するように裏
面よりエッチングして形成された薄肉の梁２３に別れて
おり、２５は質量部２４および梁２３を取り囲むように
形成された略Ｕ字形の溝で、表面側からのエッチングあ
るいは、予めＰ形層を形成しておいて、裏面からのエレ
クトロ・ケミカル・エッチングで梁２３部形成と同時に
エッチすることにより実現される。The main elements of the circuit are laid out on a semiconductor substrate as shown in FIGS. The semiconductor substrate is divided into a fixing portion 22, a mass portion 24, and a thin beam 23 formed by etching from the back surface so as to connect them, and 25 is formed so as to surround the mass portion 24 and the beam 23. This is realized by etching from the front surface side in a substantially U-shaped groove or by forming a P-type layer in advance and etching the beam 23 at the same time as electrobeam etching from the back surface.
【００１８】ピエゾ抵抗ブリッジ回路２６は梁２３上に
形成され、梁２３の長さ方向と平行なブリッジ抵抗２
本、これに垂直な２本が正方形の形に配置されて、フル
ブリッジを構成している。増幅器３３や電流源回路３２
など周辺回路は固定部２２に周辺回路部２７として配置
されている。なお、ブリッジ回路２６はすべての抵抗が
梁２３の面上に形成される必要はなく、一部を固定部２
２に設けるなど各種変形例が考えられる。The piezoresistive bridge circuit 26 is formed on the beam 23 and has a bridge resistance 2 parallel to the length direction of the beam 23.
A book and two perpendicular to it are arranged in a square shape to form a full bridge. Amplifier 33 and current source circuit 32
Peripheral circuits, etc. are arranged in the fixed portion 22 as the peripheral circuit portion 27. It is not necessary that all resistances of the bridge circuit 26 be formed on the surface of the beam 23.
Various modifications such as being provided in No. 2 are possible.
【００１９】診断抵抗２８が半導体基体の固定部２２上
に形成された周辺回路部２７に重ねて、薄膜プロセスに
よって同一基体上に形成されている。２９は台座で質量
部２４の上下方向の変位が可能となるように凹部３０が
形成されている。３１は絶縁酸化膜である。The diagnostic resistor 28 is formed on the same substrate by a thin film process, overlapping the peripheral circuit portion 27 formed on the fixed portion 22 of the semiconductor substrate. A pedestal 29 is formed with a recess 30 so that the mass portion 24 can be displaced in the vertical direction. Reference numeral 31 is an insulating oxide film.
【００２０】この構成における作用を説明すると、通常
はスイッチ３４はオフしていて、ピエゾ抵抗ブリッジ回
路２６は、加速度を受けたときに、ブリッジ回路が形成
されている梁２３に生じる歪み応力に対応したオフセッ
トを生じ、このオフセットが増幅器３３で増幅されて、
加速度信号等の出力を出すようになっている。The operation of this structure will be described. Normally, the switch 34 is turned off, and the piezoresistive bridge circuit 26 responds to the strain stress generated in the beam 23 in which the bridge circuit is formed, when it receives acceleration. Generated offset, which is amplified by the amplifier 33,
It is designed to output acceleration signals and the like.
【００２１】図示しない外部の制御システムから診断信
号が入ると、スイッチ３４がオンとなり、診断抵抗２８
が接地される。これによりピエゾ抵抗ブリッジ回路２６
の抵抗値が変化し擬似的に出力を生じる形になるので自
己診断が可能となる。When a diagnostic signal is input from an external control system (not shown), the switch 34 is turned on and the diagnostic resistor 28 is turned on.
Is grounded. As a result, the piezoresistive bridge circuit 26
The resistance value of changes and the pseudo output is generated, which enables self-diagnosis.
【００２２】診断抵抗２８の値としては、例えば応力に
よるピエゾ抵抗の変化率を０．１％、診断出力をフルレ
ンジの１０％とすると、診断抵抗２８をブリッジ回路２
６に接続した際の抵抗値の変化が１０-4程度になるよう
に設定される。したがって診断抵抗２８の値はピエゾ抵
抗のおよそ１０4倍となるので、ピエゾ抵抗を５ｋΩと
仮定すれば、診断抵抗２８は５０ＭΩ程度となる。As the value of the diagnostic resistor 28, for example, when the rate of change of piezo resistance due to stress is 0.1% and the diagnostic output is 10% of the full range, the diagnostic resistor 28 is replaced by the bridge circuit 2.
It is set so that the change in resistance value when connected to 6 is about 10 −4 . Therefore, the value of the diagnostic resistor 28 is approximately 10 4 times that of the piezoresistor, and assuming the piezoresistor to be 5 kΩ, the diagnostic resistor 28 is about 50 MΩ.
【００２３】このような高抵抗は通常の拡散抵抗では実
現が難しいが、ポリシリコン薄膜抵抗とすることによ
り、容易に基体の酸化膜上に形成できる。診断抵抗２８
はこのように設定された抵抗値を得るため、固定部２２
上で複数回折り返されて所定の長さを得ている。あるい
はまた図４に示すように、薄膜抵抗を半導体基体の外周
縁にそって延ばして診断抵抗２８’とすることもでき
る。Such a high resistance is difficult to realize with a normal diffusion resistance, but by using a polysilicon thin film resistance, it can be easily formed on the oxide film of the substrate. Diagnostic resistance 28
In order to obtain the resistance value set in this way,
A plurality of times are folded back to obtain a predetermined length. Alternatively, as shown in FIG. 4, a thin film resistor may be extended along the outer peripheral edge of the semiconductor substrate to form a diagnostic resistor 28 '.
【００２４】以上のように、この構成によればオンチッ
プで自己診断回路をつくり込むことができ、しかもその
設計の自由度が大きい。なお、図示の実施例では片持ち
梁について説明したが、これに限定されることなく、両
持ち梁方式や４方向支持の半導体加速度センサにおいて
も適用でき、同じ効果が得られる。また、スイッチ３４
は出力端子Ｐ１と診断抵抗２８の間に設けるようにして
もよい。As described above, according to this configuration, the self-diagnosis circuit can be built in on-chip, and the degree of freedom in designing is large. In the illustrated embodiment, the cantilever beam is described, but the present invention is not limited to this and can be applied to a double-supported beam system or a four-direction supported semiconductor acceleration sensor, and the same effect can be obtained. In addition, the switch 34
May be provided between the output terminal P1 and the diagnostic resistor 28.
【００２５】[0025]
【発明の効果】以上のとおり、この発明は、スイッチに
より加速度センサのブリッジ回路に診断抵抗を接続する
ようにして自己診断回路を形成し、診断抵抗を薄膜抵抗
としたから、従来の微少電流源方式と比較して、複雑な
電流源回路を省略でき、通常のプロセスによって容易に
自己診断回路のオン・チップ化された半導体加速度セン
サが得られる。また静電力方式に比較して、ギャップの
管理を必要とせず、製造の困難性も伴なわない。As described above, according to the present invention, the self-diagnosis circuit is formed by connecting the diagnostic resistor to the bridge circuit of the acceleration sensor by the switch, and the diagnostic resistor is a thin film resistor. Compared with the method, a complicated current source circuit can be omitted, and a semiconductor acceleration sensor with a self-diagnosis circuit on-chip can be easily obtained by a normal process. Further, as compared with the electrostatic force method, the management of the gap is not required and the manufacturing difficulty is not involved.
【図１】本発明の実施例を示す回路図である。FIG. 1 is a circuit diagram showing an embodiment of the present invention.
【図２】実施例の半導体基体上のレイアウトを示す図で
ある。FIG. 2 is a diagram showing a layout on a semiconductor substrate of an example.
【図３】図２のＡ−Ａ部断面図である。FIG. 3 is a sectional view taken along the line AA of FIG.
【図４】他のレイアウト例を示す図である。FIG. 4 is a diagram showing another layout example.
【図５】従来例を示す図である。FIG. 5 is a diagram showing a conventional example.
【図６】従来例における回路を示す図である。FIG. 6 is a diagram showing a circuit in a conventional example.
【図７】他の従来例を示す図である。FIG. 7 is a diagram showing another conventional example.
１ ピエゾ抵抗ブリッジ回路 ２ 電流源回路 ３ 増幅器 ４ 微少電流源 ５ スイッチ ６、１１ 梁 ７ 固定部 ８、１２ 質量部 １０ 半導体基体 １３、１４ ストッパ基板 １５ ピエゾ抵抗 １６、１７ 凹部 １８、１９ 突起部 ２０ 金属電極 ２２ 固定部 ２３ 梁 ２４ 質量部 ２５ 溝 ２６ ピエゾ抵抗ブリッジ回路 ２７ 周辺回路部 ２８、２８’ 診断抵抗 ２９ 台座 ３０ 凹部 ３１ 絶縁酸化膜 ３２ 電流源回路 ３３ 増幅器 ３４ スイッチ 1 Piezoresistive bridge circuit 2 Current source circuit 3 Amplifier 4 Micro current source 5 Switch 6, 11 Beam 7 Fixed part 8, 12 Mass part 10 Semiconductor substrate 13, 14 Stopper substrate 15 Piezoresistor 16, 17 Recessed part 18, 19 Projection part 20 Metal electrode 22 Fixed part 23 Beam 24 Mass part 25 Groove 26 Piezoresistive bridge circuit 27 Peripheral circuit part 28, 28 'Diagnostic resistance 29 Pedestal 30 Recess 31 Insulating oxide film 32 Current source circuit 33 Amplifier 34 Switch
Claims (1)
定部と質量部とを接続する薄肉の梁とに区分けされ、前
記梁上にピエゾ抵抗を有し、前記質量部の変位による前
記ピエゾ抵抗の抵抗値変化をブリッジ回路で検出する半
導体加速度センサにおいて、前記ブリッジ回路の出力端
子の一端に設けられた診断抵抗と、診断信号を受けて前
記ブリッジ回路の出力端子と接地との間を前記診断抵抗
を介して接続するスイッチを有する自己診断回路を備
え、前記診断抵抗が前記半導体基体上に形成された薄膜
抵抗で構成されていることを特徴とする半導体加速度セ
ンサ。1. A semiconductor substrate is divided into a fixed part, a mass part, and a thin beam connecting the fixed part and the mass part, and has piezo resistance on the beam, and the piezo is caused by displacement of the mass part. In a semiconductor acceleration sensor that detects a change in resistance value of a resistor with a bridge circuit, a diagnostic resistor provided at one end of an output terminal of the bridge circuit, and a diagnostic signal between the output terminal of the bridge circuit and ground are provided. A semiconductor acceleration sensor, comprising a self-diagnosis circuit having a switch connected via a diagnostic resistor, wherein the diagnostic resistor is composed of a thin film resistor formed on the semiconductor substrate.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP3293684A JP3019549B2 (en) | 1991-10-14 | 1991-10-14 | Semiconductor acceleration sensor |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP3293684A JP3019549B2 (en) | 1991-10-14 | 1991-10-14 | Semiconductor acceleration sensor |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH05107262A true JPH05107262A (en) | 1993-04-27 |
| JP3019549B2 JP3019549B2 (en) | 2000-03-13 |
Family
ID=17797897
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP3293684A Expired - Fee Related JP3019549B2 (en) | 1991-10-14 | 1991-10-14 | Semiconductor acceleration sensor |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP3019549B2 (en) |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO1998015809A1 (en) * | 1996-10-07 | 1998-04-16 | Hitachi, Ltd. | Semiconductor sensor having diagnostic function and diagnostic method for semiconductor sensor |
| JP2010025730A (en) * | 2008-07-18 | 2010-02-04 | Tokai Rika Co Ltd | Magnetic sensor device |
| JP2010085190A (en) * | 2008-09-30 | 2010-04-15 | Denso Corp | Sensor apparatus and self-diagnosis method of sensor apparatus |
| JP2012047608A (en) * | 2010-08-27 | 2012-03-08 | Hitachi Ltd | Dynamic quantity measurement equipment |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP6769389B2 (en) * | 2017-05-09 | 2020-10-14 | 株式会社島津製作所 | Gas supply control device, gas chromatograph and pressure sensor abnormality judgment method |
-
1991
- 1991-10-14 JP JP3293684A patent/JP3019549B2/en not_active Expired - Fee Related
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO1998015809A1 (en) * | 1996-10-07 | 1998-04-16 | Hitachi, Ltd. | Semiconductor sensor having diagnostic function and diagnostic method for semiconductor sensor |
| JP2010025730A (en) * | 2008-07-18 | 2010-02-04 | Tokai Rika Co Ltd | Magnetic sensor device |
| JP2010085190A (en) * | 2008-09-30 | 2010-04-15 | Denso Corp | Sensor apparatus and self-diagnosis method of sensor apparatus |
| JP2012047608A (en) * | 2010-08-27 | 2012-03-08 | Hitachi Ltd | Dynamic quantity measurement equipment |
Also Published As
| Publication number | Publication date |
|---|---|
| JP3019549B2 (en) | 2000-03-13 |
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