JPH0755523A - Flow rate sensor - Google Patents
Flow rate sensorInfo
- Publication number
- JPH0755523A JPH0755523A JP5206716A JP20671693A JPH0755523A JP H0755523 A JPH0755523 A JP H0755523A JP 5206716 A JP5206716 A JP 5206716A JP 20671693 A JP20671693 A JP 20671693A JP H0755523 A JPH0755523 A JP H0755523A
- Authority
- JP
- Japan
- Prior art keywords
- flow rate
- substrate
- circuit conductor
- detection circuit
- film
- 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.)
- Withdrawn
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Abstract
Description
【0001】[0001]
【産業上の利用分野】本発明は、極めて微小な流体の流
速を検出するための流量センサに関するものである。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a flow rate sensor for detecting an extremely minute flow velocity of a fluid.
【0002】[0002]
【従来の技術】従来、微小な流体の流速を検出する流量
センサとしては、例えば、図6(a)、(b)に示すよ
うに、極めて熱容量の小さい薄膜構造部を有する流量セ
ンサチップからなるものが知られている。これは、基板
1表面に絶縁膜2、および導体保護膜3の2層を積層し
た薄膜構造部4内に、薄膜形成技術および薄膜加工技術
によって流量を検出するための、発熱体5と一対の感温
抵抗体6、6からなる流量検出回路導体7が形成された
ものであり、基板1裏面側の流量検出回路導体7の位置
する部分に熱絶縁用の空間部8が形成されており、流量
検出回路導体7の上流側と下流側における温度差(この
場合、一対の感温抵抗体6、6の抵抗値)が流速に応じ
て変化することを利用したものである。2. Description of the Related Art Conventionally, as a flow rate sensor for detecting a minute flow velocity of a fluid, as shown in FIGS. 6A and 6B, for example, a flow rate sensor chip having a thin film structure portion having an extremely small heat capacity is formed. Things are known. This is because a pair of heating elements 5 and a heating element 5 for detecting a flow rate by a thin film forming technique and a thin film processing technique are provided in a thin film structure 4 in which two layers of an insulating film 2 and a conductor protective film 3 are laminated on a surface of a substrate 1. A flow rate detection circuit conductor 7 composed of the temperature sensitive resistors 6 is formed, and a space 8 for heat insulation is formed in a portion of the back surface of the substrate 1 where the flow rate detection circuit conductor 7 is located. This utilizes that the temperature difference between the upstream side and the downstream side of the flow rate detection circuit conductor 7 (in this case, the resistance value of the pair of temperature sensitive resistors 6, 6) changes according to the flow velocity.
【0003】この流量センサ9においては、微小な流体
の流速を検出するために、前記流量検出回路導体7領域
の熱容量を小さくして、微小な温度変化を検出する必要
があり、前記流量検出回路導体7領域は薄膜構造になっ
ているわけである。また、微小な温度変化を検出するた
めには、流量検出回路導体7領域は、基板1との間にお
いて熱の流出入の遮断を行なう必要もあり、この熱絶縁
性を向上させるため、図7(a)、(b)に示すよう
に、発熱体5や各感温抵抗体6の周辺部に熱絶縁用の孔
10、10、…を設けた構造の流量センサ11も製作さ
れていた。In this flow rate sensor 9, in order to detect the flow velocity of a minute fluid, it is necessary to reduce the heat capacity of the area of the flow rate detecting circuit conductor 7 to detect a minute temperature change. The conductor 7 region has a thin film structure. Further, in order to detect a minute temperature change, it is necessary to block the inflow and outflow of heat between the flow rate detection circuit conductor 7 region and the substrate 1, and in order to improve the heat insulation property, it is necessary to use As shown in (a) and (b), a flow rate sensor 11 having a structure in which holes 10 for thermal insulation are provided in the peripheral portion of the heating element 5 and the temperature sensitive resistors 6 has also been manufactured.
【0004】[0004]
【発明が解決しようとする課題】しかしながら、図6に
示す従来の流量センサ9においては、前述した流量検出
回路導体7領域自体の熱容量の問題とともに、絶縁膜
2、および導体保護膜3の2層によって薄膜構造部4内
の流量検出回路導体7と基板1との熱伝導量が大きくな
る、あるいは流量検出回路導体7領域内における発熱体
5と一対の感温抵抗体6、6間での絶縁膜2を通した熱
伝導量が大きくなることによりセンサの応答性が低下す
るといった問題があり、この双方の問題を解決するため
には薄膜構造部4の膜厚を薄くすべきであるが、一方、
膜厚を薄くすればする程、薄膜構造部4の機械的強度が
弱くなり、衝撃により破損しやすくなるという問題があ
った。However, in the conventional flow rate sensor 9 shown in FIG. 6, in addition to the problem of the heat capacity of the flow rate detection circuit conductor 7 region itself, the two layers of the insulating film 2 and the conductor protective film 3 are provided. As a result, the amount of heat conduction between the flow rate detection circuit conductor 7 in the thin film structure 4 and the substrate 1 becomes large, or the insulation between the heating element 5 and the pair of temperature sensitive resistors 6, 6 in the area of the flow rate detection circuit conductor 7 is increased. There is a problem that the responsiveness of the sensor decreases due to an increase in the amount of heat conduction through the film 2, and in order to solve both of these problems, the film thickness of the thin film structure portion 4 should be thin. on the other hand,
The thinner the film thickness, the weaker the mechanical strength of the thin film structure portion 4 and the more likely it is to be damaged by impact.
【0005】また、図7に示す熱絶縁用の孔10、1
0、…を設けた流量センサ11の場合には、異物が孔1
0の縁部に付着しやすく、センサの動作異常を起こしや
すいという問題があるとともに、孔のない構造のセンサ
に比べて薄膜構造部4の機械的強度が弱くなるという問
題があった。すなわち、いずれの流量センサの場合にお
いても、熱容量、または熱伝導量を小さくして流量セン
サの応答性を向上させることと、機械的強度を向上させ
ることを両立させた流量センサの実現は困難であった。Further, the holes 10 and 1 for heat insulation shown in FIG.
In the case of the flow rate sensor 11 provided with 0, ...
There is a problem that the thin film structure portion 4 is easily attached to the edge portion of 0, an abnormal operation of the sensor is likely to occur, and the mechanical strength of the thin film structure portion 4 is weaker than that of a sensor having a structure without holes. That is, in the case of any of the flow rate sensors, it is difficult to realize a flow rate sensor in which both the heat capacity or the amount of heat conduction is reduced to improve the responsiveness of the flow rate sensor and the mechanical strength is improved. there were.
【0006】本発明は、前記の課題を解決するためにな
されたものであって、熱容量、または熱伝導を小さくす
ることにより高い応答性を有するとともに、高い機械的
強度を有する流量センサを提供することを目的とする。The present invention has been made to solve the above problems, and provides a flow rate sensor having high responsiveness and high mechanical strength by reducing heat capacity or heat conduction. The purpose is to
【0007】[0007]
【課題を解決するための手段】前記の目的を達成するた
めに、請求項1記載の流量センサは、基板と、この基板
の表面に形成された絶縁層と、この絶縁層内に形成され
た流量検出回路導体とを備えてなり、前記基板の前記流
量検出回路導体の位置する部分に熱絶縁用の空間部が形
成されている流量センサにおいて、前記絶縁層の前記流
量検出回路導体の形成された領域に薄肉部が形成されて
いることを特徴とするものである。In order to achieve the above object, a flow sensor according to claim 1 is formed with a substrate, an insulating layer formed on the surface of the substrate, and an insulating layer formed in the insulating layer. A flow rate sensor comprising a flow rate detection circuit conductor, wherein a space portion for thermal insulation is formed in a portion of the substrate where the flow rate detection circuit conductor is located, wherein the flow rate detection circuit conductor of the insulating layer is formed. It is characterized in that a thin portion is formed in the open region.
【0008】また、請求項2記載の流量センサは、基板
と、この基板の表面に形成された絶縁層と、この絶縁層
の表面に形成された流量検出回路導体と、前記絶縁層の
表面に前記流量検出回路導体を覆うように形成された導
体保護層とを備えてなり、前記基板の前記流量検出回路
導体の位置する部分に熱絶縁用の空間部が形成されてい
る流量センサにおいて、前記絶縁層に、前記流量検出回
路導体の形成された位置の下方に薄肉部が形成されてい
ることを特徴とするものである。According to a second aspect of the flow sensor, a substrate, an insulating layer formed on the surface of the substrate, a flow rate detection circuit conductor formed on the surface of the insulating layer, and a surface of the insulating layer are provided. A flow rate sensor comprising a conductor protection layer formed to cover the flow rate detection circuit conductor, wherein a space for thermal insulation is formed in a portion of the substrate where the flow rate detection circuit conductor is located, In the insulating layer, a thin portion is formed below the position where the flow rate detection circuit conductor is formed.
【0009】また、請求項3記載の流量センサは、基板
と、この基板の表面に形成された絶縁層と、この絶縁層
の表面に形成された流量検出回路導体と、前記絶縁層の
表面に前記流量検出回路導体を覆うように形成された導
体保護層とを備えてなり、前記基板の前記流量検出回路
導体の位置する部分に、熱絶縁用の空間部が形成されて
いる流量センサにおいて、前記絶縁層、または前記導体
保護層のいずれか一方に、前記流量検出回路導体の周辺
部に位置させて、厚み方向に貫通する欠落部が形成さ
れ、同他方が該欠落部を覆う構成とされていることを特
徴とするものである。A flow sensor according to a third aspect of the present invention includes a substrate, an insulating layer formed on the surface of the substrate, a flow rate detection circuit conductor formed on the surface of the insulating layer, and a surface of the insulating layer. A flow sensor comprising a conductor protection layer formed so as to cover the flow rate detection circuit conductor, wherein a space for thermal insulation is formed in a portion of the substrate where the flow rate detection circuit conductor is located, One of the insulating layer and the conductor protection layer is formed in a peripheral portion of the flow rate detection circuit conductor with a cutout portion penetrating in the thickness direction, and the other is configured to cover the cutout portion. It is characterized by that.
【0010】[0010]
【作用】請求項1記載の流量センサによれば、流量検出
回路導体の領域に形成された薄肉部により流量検出回路
導体領域の熱容量が小さくなるので、流量検出回路が微
小な温度変化を検知することができる。また、その一
方、薄肉部以外の部分が流量センサの機械的強度を保持
する。According to the flow rate sensor of the present invention, since the heat capacity of the flow rate detection circuit conductor region is reduced by the thin portion formed in the flow rate detection circuit conductor region, the flow rate detection circuit detects a minute temperature change. be able to. On the other hand, the portions other than the thin portion retain the mechanical strength of the flow rate sensor.
【0011】また、請求項2記載の流量センサによれ
ば、流量検出回路導体の下方にあたる位置に形成された
薄肉部により流量検出回路導体領域の熱容量が小さくな
るので、流量検出回路が微小な温度変化を検知すること
ができる。また、その一方、流量検出回路導体周辺の薄
肉部以外の部分が流量センサの機械的強度を保持する。Further, according to the flow rate sensor of the second aspect, since the heat capacity of the flow rate detection circuit conductor area is reduced by the thin portion formed below the flow rate detection circuit conductor, the flow rate detection circuit has a small temperature. Changes can be detected. On the other hand, the portion other than the thin portion around the flow rate detection circuit conductor retains the mechanical strength of the flow rate sensor.
【0012】また、請求項3記載の流量センサによれ
ば、流量検出回路導体の周辺部に絶縁層、または導体保
護層のいずれか1層のみ存在する部分(欠落部)がで
き、この1層部が形成されたことにより流量検出回路導
体内外の熱伝導量が低減して、流量検出回路が微小な温
度変化を検知することができる。また、1層部が流量セ
ンサの機械的強度を保持する。Further, according to the flow sensor of the third aspect, there is a portion (missing portion) where only one layer of the insulating layer or the conductor protective layer exists in the peripheral portion of the flow rate detection circuit conductor. By forming the portion, the amount of heat conduction inside and outside the flow rate detection circuit conductor is reduced, and the flow rate detection circuit can detect a minute temperature change. Further, the one-layer portion retains the mechanical strength of the flow sensor.
【0013】[0013]
【実施例】以下、本発明の流量センサの第1実施例を図
1および図2を用いて説明する。図1は、本実施例の流
量センサの(a)平面図、(b)断面図を示すものであ
って、この流量センサ12は、図1(b)に示すよう
に、基板13と、この基板13の表面に形成された絶縁
膜14(絶縁層)と、この絶縁膜14の表面に形成され
た流量検出回路導体15と、これら流量検出回路導体1
5を覆うように絶縁膜14の表面に形成された導体保護
膜16(導体保護層)と、基板13の裏面側に形成され
た絶縁膜17とからなるものである。この流量検出回路
導体15は、図1(a)に示すように、ヒータ18(発
熱体)と、絶縁膜14の表面においてヒータ18の両側
方の位置に形成された感温抵抗体19、20(上流側抵
抗体19、下流側抵抗体20)とからなるものである。DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of the flow rate sensor of the present invention will be described below with reference to FIGS. FIG. 1 shows (a) a plan view and (b) a cross-sectional view of the flow rate sensor of this embodiment. The flow rate sensor 12 includes a substrate 13 and a substrate 13 as shown in FIG. 1 (b). The insulating film 14 (insulating layer) formed on the surface of the substrate 13, the flow rate detecting circuit conductor 15 formed on the surface of the insulating film 14, and the flow rate detecting circuit conductor 1
5, a conductor protective film 16 (conductor protective layer) formed on the surface of the insulating film 14 and an insulating film 17 formed on the back surface side of the substrate 13. As shown in FIG. 1A, the flow rate detection circuit conductor 15 includes a heater 18 (heating element) and temperature-sensitive resistors 19 and 20 formed at positions on both sides of the heater 18 on the surface of the insulating film 14. (Upstream-side resistor 19, downstream-side resistor 20).
【0014】そして、基板13の流量検出回路導体15
の下方にあたる部分には、基板13が部分的に取り除か
れることにより絶縁膜14を裏面側に露出させる熱絶縁
用空間部21が形成され、前記絶縁膜14、流量検出回
路導体15、および導体保護膜16が薄膜構造部22を
形成している。また、図1(a)、(b)に示すよう
に、薄膜構造部22における絶縁膜14には、流量検出
回路導体15のパターン領域の下方にそれぞれ薄肉部2
3が形成されている。Then, the flow rate detection circuit conductor 15 of the substrate 13
A space 21 for thermal insulation exposing the insulating film 14 to the back side by partially removing the substrate 13 is formed in a portion corresponding to the lower part of the insulating film 14, the insulating film 14, the flow rate detection circuit conductor 15, and the conductor protection. The film 16 forms a thin film structure 22. Further, as shown in FIGS. 1A and 1B, in the insulating film 14 in the thin film structure portion 22, the thin portion 2 is formed below the pattern region of the flow rate detection circuit conductor 15.
3 is formed.
【0015】つぎに、前記構成の流量センサ12を作成
する手順を図2を用いて説明する。まず、基板としては
厚さ200μmのシリコン基板13を用い(図2
(a))、このシリコン基板13表面に熱酸化法によっ
て膜厚500nmの酸化シリコン膜24を形成し、リソ
グラフィ技術によりこの酸化シリコン膜24をパターニ
ングする。(図2(b))。なお、ここでパターニング
される酸化シリコン膜24の平面形状は、最終的には、
図1(a)に示す薄肉部23の平面形状となるものであ
り、後ほど、流量検出回路導体15パターンが形成され
る領域である。Next, a procedure for producing the flow rate sensor 12 having the above-mentioned structure will be described with reference to FIG. First, a 200 μm thick silicon substrate 13 is used as the substrate (see FIG.
(A)) A 500 nm-thickness silicon oxide film 24 is formed on the surface of the silicon substrate 13 by a thermal oxidation method, and the silicon oxide film 24 is patterned by a lithography technique. (FIG.2 (b)). The planar shape of the silicon oxide film 24 patterned here is finally
It is a planar shape of the thin portion 23 shown in FIG. 1A, and is a region where the flow rate detection circuit conductor 15 pattern is formed later.
【0016】つぎに、シリコン基板13の表面に窒化シ
リコンからなる膜厚800nmの絶縁膜14をスパッタ
法、プラズマCVD法等の方法により堆積させる(図3
(c))。その後、酸化シリコン膜24上の絶縁膜14
の膜厚が400nmになるまで絶縁膜14を研磨する
(図3(d))。一方、シリコン基板13の裏面に窒化
シリコンからなる裏面絶縁膜17をスパッタ法、プラズ
マCVD法等の方法により堆積させる(図3(d))。
なお、裏面絶縁膜17は、後述するように、シリコン基
板13に熱絶縁用空間部21を形成する際のエッチング
加工のマスクとするために設けられるものである。Next, an insulating film 14 made of silicon nitride and having a thickness of 800 nm is deposited on the surface of the silicon substrate 13 by a method such as a sputtering method or a plasma CVD method (FIG. 3).
(C)). Then, the insulating film 14 on the silicon oxide film 24
The insulating film 14 is polished until the film thickness becomes 400 nm (FIG. 3D). On the other hand, a back surface insulating film 17 made of silicon nitride is deposited on the back surface of the silicon substrate 13 by a method such as a sputtering method or a plasma CVD method (FIG. 3D).
The back surface insulating film 17 is provided as a mask for etching when the heat insulating space 21 is formed in the silicon substrate 13, as described later.
【0017】つぎに、絶縁膜14表面にヒータ18およ
び感温抵抗体19、20を形成する金属膜を成膜し、リ
ソグラフィ技術により所望の回路パターン形状に加工す
る(図3(e))。なお、この金属膜は、Ni,Ni−
Fe,Pt等を用いて、真空蒸着法、スパッタ法等によ
り膜厚80nmに成膜したものである。そして、窒化シ
リコンからなる膜厚100nmの導体保護膜16を絶縁
膜14または裏面絶縁膜17の場合と同様の方法により
形成する(図3(f))。Next, a metal film for forming the heater 18 and the temperature sensitive resistors 19 and 20 is formed on the surface of the insulating film 14 and processed into a desired circuit pattern shape by a lithography technique (FIG. 3 (e)). This metal film is made of Ni, Ni-
A film having a film thickness of 80 nm is formed using Fe, Pt, or the like by a vacuum deposition method, a sputtering method, or the like. Then, the conductor protective film 16 made of silicon nitride and having a film thickness of 100 nm is formed by the same method as the case of the insulating film 14 or the back surface insulating film 17 (FIG. 3F).
【0018】つぎに、ヒータ18および感温抵抗体1
9、20の形成された位置に熱絶縁用空間部21を形成
するため、裏面絶縁膜17のパターニングを行なってヒ
ータ18および感温抵抗体19、20の下方にあたる部
分を除去し、シリコン面25(基板13の裏面)を露出
させる(図3(g))。そして、異方性エッチングによ
り露出したシリコン面25から絶縁膜14の裏面が露出
するまで基板13のエッチングを行ない、熱絶縁用空間
部21を形成する(図3(h))。なお、異方性エッチ
ング液としては、一般に用いられているKOH(水酸化
カリウム)溶液を用いる。このエッチング液は、シリコ
ンをエッチングするが、窒化シリコン、酸化シリコン等
の絶縁膜はエッチングしない性質のものである。Next, the heater 18 and the temperature sensitive resistor 1
In order to form the heat insulating space portion 21 at the position where 9 and 20 are formed, the back surface insulating film 17 is patterned to remove the portions below the heater 18 and the temperature sensitive resistors 19 and 20, and the silicon surface 25 The back surface of the substrate 13 is exposed (FIG. 3G). Then, the substrate 13 is etched until the back surface of the insulating film 14 is exposed from the silicon surface 25 exposed by anisotropic etching to form the heat insulating space portion 21 (FIG. 3 (h)). A commonly used KOH (potassium hydroxide) solution is used as the anisotropic etching solution. This etching liquid has a property of etching silicon, but not of an insulating film such as silicon nitride or silicon oxide.
【0019】つぎに、前述したように、熱絶縁用空間部
21を形成した際、酸化シリコン膜24が露出するの
で、バッファードフッ酸でこの酸化シリコン膜24を除
去する(図3(i))。このとき、酸化シリコンのバッ
ファードフッ酸に対するエッチング速度は、窒化シリコ
ンより10倍以上早いので、絶縁膜14をエッチングす
ることなく、酸化シリコン膜24のみを選択的に除去す
ることができる。以上の手順により、膜厚900nmの
薄膜構造部22(流量検出回路導体15領域)の一部分
の絶縁膜14の膜厚を400nmと薄くした流量センサ
12を製作することができる。Next, as described above, since the silicon oxide film 24 is exposed when the heat insulating space 21 is formed, the silicon oxide film 24 is removed with buffered hydrofluoric acid (FIG. 3 (i)). ). At this time, the etching rate of silicon oxide with respect to buffered hydrofluoric acid is 10 times or more faster than that of silicon nitride. Therefore, only the silicon oxide film 24 can be selectively removed without etching the insulating film 14. Through the above procedure, it is possible to manufacture the flow rate sensor 12 in which the thickness of the insulating film 14 which is a part of the thin film structure portion 22 (flow rate detection circuit conductor 15 region) having a thickness of 900 nm is reduced to 400 nm.
【0020】本実施例の流量センサ12は、流量検出回
路導体15領域にあたる薄膜構造部22の一部に薄肉部
23を形成したものであり、ヒータ18下部の絶縁膜1
4が薄いためにヒータ部の熱容量を小さくすることがで
きるので、ヒータの消費電力を低減することができる。
さらに、感温抵抗体19、20下部の絶縁膜14も薄い
ために感温抵抗体部の熱容量を小さくすることができる
ので、熱応答を向上させ、流量センサ12を感度の高い
ものとすることができる。The flow rate sensor 12 of this embodiment has a thin portion 23 formed in a part of the thin film structure portion 22 corresponding to the area of the flow rate detection circuit conductor 15, and the insulating film 1 below the heater 18 is formed.
Since 4 is thin, it is possible to reduce the heat capacity of the heater portion, so that it is possible to reduce the power consumption of the heater.
Furthermore, since the insulating film 14 below the temperature sensitive resistors 19 and 20 is also thin, the heat capacity of the temperature sensitive resistor portion can be reduced, so that the thermal response is improved and the flow rate sensor 12 has high sensitivity. You can
【0021】一方、薄膜構造部22の薄肉部23以外の
部分は、この薄膜構造部22の機械的強度を保持する効
果を有しており、衝撃等による薄膜構造部22の破損を
防止することができる。すなわち、本実施例の流量セン
サ12は、低消費電力、高感度といった良好な特性と高
い機械的強度の双方を合わせ持ったものとすることがで
きる。On the other hand, the portion of the thin film structure portion 22 other than the thin portion 23 has an effect of maintaining the mechanical strength of the thin film structure portion 22, and prevents the thin film structure portion 22 from being damaged by an impact or the like. You can That is, the flow rate sensor 12 of the present embodiment can have both good characteristics such as low power consumption and high sensitivity and high mechanical strength.
【0022】なお、本実施例においては、図1(a)に
示すように、ヒータ18、一対の感温抵抗体19、20
それぞれの領域に一括した大面積の薄肉部23を形成す
るようにしたが、薄肉部23の面積は小さいほど薄膜構
造部22の機械的強度を向上させることができるので、
例えば、図3に示すように、ヒータ26、感温抵抗体2
7、28の回路パターンを変更して熱容量を小さくする
特性面の効果は保持しつつ、ヒータ26、感温抵抗体2
7、28それぞれの領域において小分割した薄肉部2
9、29、…を形成するようにして機械的強度をさらに
向上させることもできる。In this embodiment, as shown in FIG. 1A, the heater 18 and the pair of temperature sensitive resistors 19 and 20 are used.
Although the large-area thin-walled portions 23 are collectively formed in each region, the smaller the area of the thin-walled portions 23, the more the mechanical strength of the thin-film structure 22 can be improved.
For example, as shown in FIG. 3, the heater 26, the temperature sensitive resistor 2
The heater 26 and the temperature sensitive resistor 2 are maintained while maintaining the effect of the characteristic of reducing the heat capacity by changing the circuit patterns of 7 and 28.
Thin-walled portion 2 divided into small areas 7 and 28 respectively
It is also possible to further improve the mechanical strength by forming 9, 29, ....
【0023】つぎに、本発明における流量センサの第2
実施例を図4および図5を用いて説明する。図4は、本
実施例の流量センサの(a)斜視図、(b)断面図を示
すものである。この流量センサ31は第1実施例の流量
センサ12とほぼ同様の構成を持つものであって、図4
(b)に示すように、基板13と、絶縁膜14と、流量
検出回路導体15と、導体保護膜16とからなるもので
ある。また、流量検出回路導体15は、図4(a)に示
すように、ヒータ18(発熱体)と、一対の感温抵抗体
19、20(上流側抵抗体19、下流側抵抗体20)と
からなるものである。Next, the second embodiment of the flow rate sensor in the present invention.
An example will be described with reference to FIGS. 4 and 5. FIG. 4 shows a perspective view (a) and a sectional view (b) of the flow sensor of the present embodiment. The flow rate sensor 31 has substantially the same configuration as that of the flow rate sensor 12 of the first embodiment.
As shown in (b), it comprises a substrate 13, an insulating film 14, a flow rate detection circuit conductor 15, and a conductor protection film 16. As shown in FIG. 4A, the flow rate detection circuit conductor 15 includes a heater 18 (heating element) and a pair of temperature-sensitive resistors 19 and 20 (upstream-side resistor 19, downstream-side resistor 20). It consists of
【0024】そして、図4(b)に示すように、基板1
3の流量検出回路導体15の下方にあたる部分には熱絶
縁用空間部21が形成されている。また、図4(a)、
(b)に示すように、流量検出回路導体15領域である
薄膜構造部22には、絶縁膜14のみが部分的に除去さ
れた保護膜1層部(欠落部)30、30、…がヒータ1
8および感温抵抗体19、20の周辺に多数、形成され
ている。なお、図4(a)に示す保護膜1層部30の平
面形状は、従来の技術として図7で示した流量センサ1
1における熱絶縁用の孔10の形状と同様のものであ
る。Then, as shown in FIG. 4B, the substrate 1
A space 21 for heat insulation is formed in a portion below the flow rate detection circuit conductor 15 of FIG. In addition, FIG.
As shown in (b), in the thin film structure portion 22 which is the area of the flow rate detection circuit conductor 15, the protective film 1 layer portion (missing portion) 30, 30, ... In which only the insulating film 14 is partially removed is a heater. 1
A large number are formed around the temperature sensor 8 and the temperature sensitive resistors 19 and 20. The planar shape of the protective film 1 layer portion 30 shown in FIG. 4A is the same as that of the flow sensor 1 shown in FIG.
The shape is the same as that of the hole 10 for heat insulation in FIG.
【0025】つぎに、前記構成の流量センサ31を作成
する手順を図5を用いて説明する。なお、各工程の具体
的仕様については、第1実施例とほぼ同様であり詳細な
説明は省略する。まず、シリコン基板13の表面に絶縁
膜14を堆積させた後(図5(a))、この絶縁膜14
をパターニングして保護膜1層部を形成する箇所の絶縁
膜14を除去する(図5(b))。つぎに、絶縁膜14
表面にヒータ18および感温抵抗体19、20を形成す
る金属膜32を成膜した後、回路パターン形状に加工す
る(図5(c))。Next, the procedure for producing the flow rate sensor 31 having the above-mentioned structure will be described with reference to FIG. The specific specifications of each step are almost the same as those in the first embodiment, and detailed description thereof will be omitted. First, after depositing the insulating film 14 on the surface of the silicon substrate 13 (FIG. 5A), the insulating film 14 is deposited.
Is patterned to remove the insulating film 14 at the portion where the protective film 1 layer portion is to be formed (FIG. 5B). Next, the insulating film 14
After forming the metal film 32 forming the heater 18 and the temperature sensitive resistors 19 and 20 on the surface, it is processed into a circuit pattern shape (FIG. 5C).
【0026】さらに、導体保護膜16を堆積させ(図5
(d))、この導体保護膜16をパターニングする(図
5(e))。なお、このパターニングは、ヒータ18お
よび感温抵抗体19、20の端子部33において導体保
護膜16を除去し、導線等と接合のため金属膜32表面
を露出させるためのものである。つぎに、シリコン基板
13の裏面側のエッチングを行ない、熱絶縁用空間部2
1を形成する(図5(f))。以上の手順により、薄膜
構造部22(流量検出回路導体15領域)に、絶縁膜1
4が除去され導体保護膜16のみからなる保護膜1層部
30が形成された流量センサ31を製作することができ
る。Further, a conductor protection film 16 is deposited (see FIG. 5).
(D)), this conductor protection film 16 is patterned (FIG. 5E). The patterning is for removing the conductor protection film 16 at the terminal portion 33 of the heater 18 and the temperature sensitive resistors 19 and 20 and exposing the surface of the metal film 32 for bonding with a conductor or the like. Next, the back side of the silicon substrate 13 is etched to form the heat insulating space 2.
1 is formed (FIG. 5 (f)). By the procedure described above, the insulating film 1 is formed on the thin film structure portion 22 (flow rate detection circuit conductor 15 region).
It is possible to manufacture the flow rate sensor 31 in which the protective film 1-layer portion 30 including only the conductor protective film 16 is removed and the protective film 1 is removed.
【0027】本実施例の流量センサ31は、流量検出回
路導体15領域にあたる薄膜構造部22の一部に保護膜
1層部30、30、…を形成したものであり、この保護
膜1層部30、30、…を介した熱伝導量は、図6で示
した従来の流量センサ9における絶縁膜2層を介した熱
伝導量に比べて半分以下にまで低減される。したがっ
て、ヒータ18で発生した熱が絶縁膜を通して感温抵抗
体19、20に伝達されたり、熱が感温抵抗体19、2
0から基板13に伝達される割合が減少し、すなわち、
熱絶縁性が向上して、流量センサ31を感度の高いもの
とすることができる。In the flow rate sensor 31 of this embodiment, the protective film 1 layer portions 30, 30, ... Are formed on a part of the thin film structure portion 22 corresponding to the region of the flow rate detection circuit conductor 15. The protective film 1 layer portion is formed. The amount of heat conduction through 30, 30, ... Is reduced to less than half the amount of heat conduction through the two insulating film layers in the conventional flow sensor 9 shown in FIG. Therefore, the heat generated by the heater 18 is transferred to the temperature sensitive resistors 19 and 20 through the insulating film, or the heat is generated.
The rate of transmission from 0 to the substrate 13 is reduced, that is,
The heat insulating property is improved, and the flow rate sensor 31 can be made highly sensitive.
【0028】一方、本流量センサ31の保護膜1層部3
0、30、…は、図7で示した従来の流量センサ11に
おける熱絶縁用の孔10、10、…を導体保護膜161
層で埋めた形に相当するので、図7の流量センサ11に
比べて機械的強度を向上させることができるとともに、
孔10の縁部に異物が付着してセンサが動作異常を起こ
すといった不具合もなくすことができる。すなわち、本
実施例の流量センサ31は、良好な感度と高い機械的強
度の双方を合わせ持ったものとすることができる。On the other hand, the protective film 1 layer portion 3 of the present flow sensor 31.
0, 30, ... Are the heat insulating holes 10, 10, ... In the conventional flow sensor 11 shown in FIG.
Since it corresponds to a shape filled with layers, it is possible to improve mechanical strength as compared with the flow rate sensor 11 of FIG.
It is possible to eliminate the problem that foreign matter adheres to the edge of the hole 10 and causes the sensor to malfunction. That is, the flow rate sensor 31 of this embodiment can have both good sensitivity and high mechanical strength.
【0029】なお、本実施例においては、保護膜1層部
30、30、…を形成するに際して、絶縁膜14をパタ
ーニング、除去して、導体保護膜16により保護膜1層
部30、30、…を形成するようにしたが、この構造に
代えて、導体保護膜16をパターニング、除去して、絶
縁膜14により保護膜1層部30、30、…を形成する
ようにしてもよい。In the present embodiment, when forming the protective film 1-layer portions 30, 30, ..., The insulating film 14 is patterned and removed, and the conductor protective film 16 is used to form the protective film 1-layer portions 30, 30 ,. .. are formed, the conductor protective film 16 may be patterned and removed to form the protective film 1 layer portions 30, 30, ... With the insulating film 14 instead of this structure.
【0030】[0030]
【発明の効果】以上、詳細に説明したように、請求項1
記載の流量センサは、流量検出回路導体領域に薄肉部が
形成されているので、薄肉部が存在しない従来の流量セ
ンサに比べて、流量検出回路導体領域の熱容量が小さく
なり、流量検出回路の熱応答性が向上する。また、その
一方、薄肉部以外の部分が流量センサの機械的強度を保
持する。したがって、本流量センサは、応答性が高いも
のであると同時に、高い機械的強度を持つものとするこ
とができる。As described above in detail, the first aspect of the present invention is as follows.
Since the flow sensor described has the thin portion formed in the flow detection circuit conductor area, the heat capacity of the flow detection circuit conductor area becomes smaller than that of the conventional flow sensor in which the thin portion does not exist, and the heat of the flow detection circuit is reduced. Responsiveness is improved. On the other hand, the portions other than the thin portion retain the mechanical strength of the flow rate sensor. Therefore, the present flow rate sensor can have high responsiveness and high mechanical strength at the same time.
【0031】また、請求項2記載の流量センサは、流量
検出回路導体の下方にあたる位置に薄肉部が形成されて
いるので、薄肉部が存在しない従来の流量センサに比べ
て、流量検出回路導体領域の熱容量が小さくなり、流量
検出回路の熱応答性が向上する。また、その一方、流量
検出回路導体周辺の薄肉部以外の部分が流量センサの機
械的強度を保持する。したがって、本流量センサは、応
答性が高いものであると同時に、高い機械的強度を持つ
ものとすることができる。Further, in the flow sensor according to the second aspect, since the thin portion is formed at a position below the flow detecting circuit conductor, the flow detecting circuit conductor region is provided as compared with the conventional flow sensor in which the thin portion does not exist. The heat capacity of is reduced, and the thermal response of the flow rate detection circuit is improved. On the other hand, the portion other than the thin portion around the flow rate detection circuit conductor retains the mechanical strength of the flow rate sensor. Therefore, the present flow rate sensor can have high responsiveness and high mechanical strength at the same time.
【0032】また、請求項3記載の流量センサは、流量
検出回路導体の周辺部に、絶縁層、または導体保護層の
いずれか一方が欠落した欠落部ができ、この欠落部にい
ずれか1層のみが存在する構成となっているので、流量
検出回路導体領域全てが2層で構成された従来の流量セ
ンサに比べて、流量検出回路導体領域内外の熱伝導量が
低減して、流量検出回路の熱応答性が向上する。また、
孔等の欠損部分が存在しないので、流量センサの機械的
強度も保持されている。したがって、本流量センサは、
応答性が高いものであると同時に、高い機械的強度を持
つものとすることができる。Further, in the flow sensor according to the third aspect of the invention, there is a missing portion in which either the insulating layer or the conductor protection layer is missing in the peripheral portion of the flow detecting circuit conductor, and the missing portion has one layer. Since only the flow rate detecting circuit conductor area has two layers, the amount of heat conduction inside and outside the flow rate detecting circuit conductor area is smaller than that of the conventional flow rate sensor in which the flow rate detecting circuit conductor area is entirely composed of two layers. The thermal response of is improved. Also,
Since there is no defective portion such as a hole, the mechanical strength of the flow sensor is maintained. Therefore, this flow sensor
In addition to being highly responsive, it can have high mechanical strength.
【図1】本発明における流量センサの第1実施例を示す
(a)平面図、(b)(a)におけるA―A線に沿う断
面図である。1A is a plan view showing a first embodiment of a flow rate sensor according to the present invention, and FIG. 1B is a sectional view taken along line AA in FIG.
【図2】同実施例の製作手順を示す図である。FIG. 2 is a diagram showing a manufacturing procedure of the embodiment.
【図3】同実施例の変形例を示す平面図である。FIG. 3 is a plan view showing a modified example of the same embodiment.
【図4】本発明における流量センサの第2実施例を示す
(a)斜視図、(b)(a)におけるB―B線に沿う断
面図である。4A is a perspective view showing a second embodiment of the flow rate sensor according to the present invention, and FIG. 4B is a sectional view taken along line BB in FIG. 4B.
【図5】同実施例の製作手順を示す図である。FIG. 5 is a diagram showing a manufacturing procedure of the embodiment.
【図6】従来の流量センサの一例を示す(a)斜視図、
(b)(a)におけるC―C線に沿う断面図である。FIG. 6A is a perspective view showing an example of a conventional flow rate sensor,
(B) It is sectional drawing which follows CC line in (a).
【図7】従来の流量センサの他の一例を示す(a)斜視
図、(b)(a)におけるD―D線に沿う断面図であ
る。7 (a) is a perspective view showing another example of a conventional flow rate sensor, and FIG. 7 (b) is a sectional view taken along the line D-D in FIG. 7 (a).
12、31 流量センサ 13 基板 14 絶縁膜(絶縁層) 15 流量検出回路導体 16 導体保護膜(導体保護層) 21 熱絶縁用空間部 23 薄肉部 30 保護膜1層部(欠落部) 12, 31 Flow rate sensor 13 Substrate 14 Insulating film (insulating layer) 15 Flow rate detection circuit conductor 16 Conductor protective film (conductor protective layer) 21 Thermal insulation space 23 Thin portion 30 Protective film 1 layer (missing part)
Claims (3)
縁層と、この絶縁層内に形成された流量検出回路導体と
を備えてなり、 前記基板の前記流量検出回路導体の位置する部分に熱絶
縁用の空間部が形成されている流量センサにおいて、 前記絶縁層の前記流量検出回路導体の形成された領域に
薄肉部が形成されていることを特徴とする流量センサ。1. A substrate, an insulating layer formed on a surface of the substrate, and a flow rate detecting circuit conductor formed in the insulating layer, the portion of the substrate where the flow rate detecting circuit conductor is located. A flow sensor in which a space for heat insulation is formed in the flow sensor, wherein a thin portion is formed in a region of the insulating layer where the flow detection circuit conductor is formed.
縁層と、この絶縁層の表面に形成された流量検出回路導
体と、前記絶縁層の表面に前記流量検出回路導体を覆う
ように形成された導体保護層とを備えてなり、 前記基板の前記流量検出回路導体の位置する部分に熱絶
縁用の空間部が形成されている流量センサにおいて、 前記絶縁層に、前記流量検出回路導体の形成された位置
の下方に薄肉部が形成されていることを特徴とする流量
センサ。2. A substrate, an insulating layer formed on the surface of the substrate, a flow rate detecting circuit conductor formed on the surface of the insulating layer, and a surface of the insulating layer covering the flow rate detecting circuit conductor. A flow sensor comprising a conductor protection layer formed, wherein a space portion for thermal insulation is formed in a portion of the substrate where the flow rate detection circuit conductor is located, wherein the flow rate detection circuit conductor is provided in the insulating layer. A flow rate sensor characterized in that a thin portion is formed below the position where is formed.
縁層と、この絶縁層の表面に形成された流量検出回路導
体と、前記絶縁層の表面に前記流量検出回路導体を覆う
ように形成された導体保護層とを備えてなり、 前記基板の前記流量検出回路導体の位置する部分に熱絶
縁用の空間部が形成されている流量センサにおいて、 前記絶縁層、または前記導体保護層のいずれか一方に、
前記流量検出回路導体の周辺部に位置させて、厚み方向
に貫通する欠落部が形成され、同他方が該欠落部を覆う
構成とされていることを特徴とする流量センサ。3. A substrate, an insulating layer formed on the surface of the substrate, a flow rate detecting circuit conductor formed on the surface of the insulating layer, and a surface of the insulating layer covering the flow rate detecting circuit conductor. In a flow rate sensor comprising a formed conductor protection layer, wherein a space portion for thermal insulation is formed in a portion of the substrate where the flow rate detection circuit conductor is located, the insulating layer or the conductor protection layer On either side,
A flow rate sensor, characterized in that a cutout portion penetrating in the thickness direction is formed at a peripheral portion of the flow detection circuit conductor, and the other portion covers the cutout portion.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP5206716A JPH0755523A (en) | 1993-08-20 | 1993-08-20 | Flow rate sensor |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP5206716A JPH0755523A (en) | 1993-08-20 | 1993-08-20 | Flow rate sensor |
Publications (1)
Publication Number | Publication Date |
---|---|
JPH0755523A true JPH0755523A (en) | 1995-03-03 |
Family
ID=16527931
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
JP5206716A Withdrawn JPH0755523A (en) | 1993-08-20 | 1993-08-20 | Flow rate sensor |
Country Status (1)
Country | Link |
---|---|
JP (1) | JPH0755523A (en) |
Cited By (8)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPH10221142A (en) * | 1997-02-03 | 1998-08-21 | Omron Corp | Semiconductor flow sensor |
JP2000131112A (en) * | 1998-10-28 | 2000-05-12 | Mitsubishi Electric Corp | Heat-sensitive flow sensor |
JP2002243516A (en) * | 2001-02-13 | 2002-08-28 | Denso Corp | Method of manufacturing sensor having thin film part |
JP2002243517A (en) * | 2001-02-13 | 2002-08-28 | Denso Corp | Flow sensor |
KR100515422B1 (en) * | 1995-07-29 | 2005-11-21 | 로베르트 보쉬 게엠베하 | Mass flow sensor |
DE19838647B4 (en) * | 1998-01-13 | 2008-01-10 | Mitsubishi Denki K.K. | Flußmeßelement |
DE19857549B4 (en) * | 1998-12-14 | 2009-12-24 | Robert Bosch Gmbh | Sensor with a membrane and method of making the sensor with a membrane |
US11351313B2 (en) * | 2017-02-23 | 2022-06-07 | The Trustees Of Princeton University | System and method for monitoring injection site pressure |
-
1993
- 1993-08-20 JP JP5206716A patent/JPH0755523A/en not_active Withdrawn
Cited By (12)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
KR100515422B1 (en) * | 1995-07-29 | 2005-11-21 | 로베르트 보쉬 게엠베하 | Mass flow sensor |
JPH10221142A (en) * | 1997-02-03 | 1998-08-21 | Omron Corp | Semiconductor flow sensor |
DE19838647B4 (en) * | 1998-01-13 | 2008-01-10 | Mitsubishi Denki K.K. | Flußmeßelement |
JP2000131112A (en) * | 1998-10-28 | 2000-05-12 | Mitsubishi Electric Corp | Heat-sensitive flow sensor |
US6675644B2 (en) | 1998-10-28 | 2004-01-13 | Mitsubishi Denki Kabushiki Kaisha | Thermo-sensitive flow rate sensor |
DE19919398B4 (en) * | 1998-10-28 | 2006-05-04 | Mitsubishi Denki K.K. | Heat sensitive flow rate sensor |
DE19857549B4 (en) * | 1998-12-14 | 2009-12-24 | Robert Bosch Gmbh | Sensor with a membrane and method of making the sensor with a membrane |
JP2002243516A (en) * | 2001-02-13 | 2002-08-28 | Denso Corp | Method of manufacturing sensor having thin film part |
JP2002243517A (en) * | 2001-02-13 | 2002-08-28 | Denso Corp | Flow sensor |
JP4622114B2 (en) * | 2001-02-13 | 2011-02-02 | 株式会社デンソー | Flow sensor |
JP4639487B2 (en) * | 2001-02-13 | 2011-02-23 | 株式会社デンソー | Manufacturing method of sensor having thin film portion |
US11351313B2 (en) * | 2017-02-23 | 2022-06-07 | The Trustees Of Princeton University | System and method for monitoring injection site pressure |
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