JP2518352B2 - Semiconductor flow velocity sensor - Google Patents
Semiconductor flow velocity sensorInfo
- Publication number
- JP2518352B2 JP2518352B2 JP63133080A JP13308088A JP2518352B2 JP 2518352 B2 JP2518352 B2 JP 2518352B2 JP 63133080 A JP63133080 A JP 63133080A JP 13308088 A JP13308088 A JP 13308088A JP 2518352 B2 JP2518352 B2 JP 2518352B2
- Authority
- JP
- Japan
- Prior art keywords
- heating element
- stopper layer
- flow velocity
- layer
- velocity sensor
- 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.)
- Expired - Fee Related
Links
Landscapes
- Measuring Volume Flow (AREA)
Description
【発明の詳細な説明】 〔産業上の利用分野〕 この発明は、半導体基板上に発熱体と温度検出素子と
を形成した半導体流速センサに関し、特に発熱体と温度
検出素子を設けた半導体層を薄くした改良にかかわる。Description: TECHNICAL FIELD The present invention relates to a semiconductor flow velocity sensor in which a heating element and a temperature detecting element are formed on a semiconductor substrate, and particularly to a semiconductor layer provided with the heating element and the temperature detecting element. Involved in thinning improvement.
第６図及び第７図は例えば特開昭60-1525号公報に示
された従来の半導体流速センサを示す平面図及び断面図
である。図において、１はシリコンからなる半導体基板
で、下半部はｎ型領域1aからなるが、上半部はｐ型不純
物拡散領域1bにされている。２は領域1bに拡散抵抗によ
り形成された発熱素子で、流体の流れ方向Ｆに対し下流
端に位置している。３及び４は領域1bに形成されたダイ
オードからなる第１及び第２の温度検出素子、５はSiO2
からなる絶縁膜、６はアルミ蒸着による電極、７はSiO2
などからなる保護膜である。なお、電極６部上の保護膜
７は除去されている。基板１の下面には中央にエツチン
グにより凹部８が形成され、上部を薄くしてある。これ
により、温度勾配を大きくし、センサ自体の熱容量が小
さくなることにより応答性を改善している。6 and 7 are a plan view and a sectional view showing a conventional semiconductor flow velocity sensor disclosed in, for example, Japanese Patent Laid-Open No. 60-1525. In the figure, reference numeral 1 is a semiconductor substrate made of silicon, and the lower half part thereof is an n-type region 1a, while the upper half part is a p-type impurity diffusion region 1b. A heating element 2 is formed in the region 1b by diffusion resistance and is located at the downstream end with respect to the fluid flow direction F. 3 and 4 are the first and second temperature detecting elements formed of the diode formed in the region 1b, and 5 is SiO 2
An insulating film made of, 6 is an electrode formed by aluminum vapor deposition, 7 is SiO 2
It is a protective film composed of. The protective film 7 on the electrode 6 part is removed. A recess 8 is formed in the center of the lower surface of the substrate 1 by etching, and the upper portion is thin. As a result, the temperature gradient is increased and the heat capacity of the sensor itself is reduced, thereby improving the responsiveness.
上記のような従来の半導体流速センサでは、基板１を
エツチングして凹部８を形成するのに、深さにばらつき
があるので深くできず、上部の薄肉部の厚さが余り薄く
できなく、横方向の熱抵抗が小さく、発熱体２の温度を
上げると流体温度検出素子３、４の温度が上り、流速検
出精度が低下するという問題点があつた。さらに、熱容
量が余り小さくならず、応答性もそれだけ下がるという
問題点があつた。In the conventional semiconductor flow velocity sensor as described above, when the substrate 1 is etched to form the recessed portion 8, it is not possible to make it deep because there is variation in depth, and the thickness of the upper thin portion cannot be made too thin. The thermal resistance in the direction is small, and when the temperature of the heating element 2 is raised, the temperature of the fluid temperature detecting elements 3 and 4 rises, and the accuracy of flow velocity detection deteriorates. Further, there is a problem that the heat capacity is not so small and the responsiveness is lowered accordingly.
この発明は、このような問題点を解決するためになさ
れたもので、半導体基板の上方の発熱素子が形成された
層の横方向の熱抵抗を大きくし、発熱素子の熱容量が小
さくでき発熱素子から温度検出素子への熱伝導損失が減
少され、ドリフトが小さく応答性が向上され発熱素子か
ら流体への熱伝達率が上がり感度が増大する半導体流速
センサを得ることを目的としている。The present invention has been made in order to solve such a problem, and it is possible to increase the lateral thermal resistance of a layer on which a heating element is formed above a semiconductor substrate and to reduce the heat capacity of the heating element. It is an object of the present invention to obtain a semiconductor flow velocity sensor in which the heat conduction loss to the temperature detection element is reduced, the drift is small, the response is improved, the heat transfer coefficient from the heating element to the fluid is increased, and the sensitivity is increased.
この発明にかかる半導体流速センサは、半導体基板上
に絶縁層からなるエツチングストツパ層を形成し、この
ストツパ層上に温度検出素子と発熱素子を形成し、これ
らの温度検出素子と発熱素子及びストツパ層上に保護膜
を形成し、半導体基板の裏側から上記発熱素子部に対応
する範囲でエツチングによりストツパ層に達する凹部を
形成し、保護膜と絶縁層に発熱素子の両側位置のスリツ
トを設け凹部に連通させたものである。In the semiconductor flow velocity sensor according to the present invention, an etching stopper layer made of an insulating layer is formed on a semiconductor substrate, a temperature detecting element and a heat generating element are formed on this stopper layer, and these temperature detecting element, heat generating element and stopper are formed. A protective film is formed on the layer, a recess reaching the stopper layer is formed by etching from the back side of the semiconductor substrate in a range corresponding to the heating element section, and slits on both sides of the heating element are provided in the protective film and the insulating layer. It was made to communicate with.
この発明においては、発熱素子部は、下方の半導体基
板は凹部により除かれており、薄厚さのストツパ層上に
あり、かつ、両側にスリツトが設けられており、横方向
の熱抵抗が極めて大きく、発熱素子の熱容量が小さくて
よく、温度検出素子への熱伝導損失が減少し流速変化に
対する応答性が向上する。In the present invention, the heating element portion has the lower semiconductor substrate removed by the concave portion, is on the stopper layer having a thin thickness, and has the slits on both sides, and has a very large lateral thermal resistance. The heat capacity of the heat generating element may be small, the heat conduction loss to the temperature detecting element is reduced, and the responsiveness to the flow velocity change is improved.
第１図及び第２図はこの発明による半導体流速検出セ
ンサの一実施例を示す平面図及び断面図である。図にお
いて、11は半導体基板で、上部の絶縁層からなるエツチ
ングストツパ層（以下「ストツパ層」と称する）12上
に、温度検出素子14と発熱素子15とが流体の流れ方向Ｆ
に対し間隔をあけて形成され、それぞれ複数条のトリミ
ング溝14aと15aとが設けられ、抵抗値を調整している。
16、17は電極、18は各素子14、15ストツパ層12を覆う保
護膜である。ストツパ層12及び保護膜18には、発熱素子
15の両側位置にスリツト19が設けられている。基板11に
は、裏面からのエツチングによりストツパ層に達する凹
部20が形成されており、スリツト19に連通している。1 and 2 are a plan view and a sectional view showing an embodiment of a semiconductor flow velocity detecting sensor according to the present invention. In the figure, 11 is a semiconductor substrate, on the etching stopper layer (hereinafter referred to as "stopper layer") 12 made of an insulating layer, a temperature detecting element 14 and a heating element 15 are arranged in a fluid flow direction F.
A plurality of strips of trimming grooves 14a and 15a are provided at intervals with respect to each other to adjust the resistance value.
Reference numerals 16 and 17 are electrodes, and 18 is a protective film which covers the respective element 14 and 15 stop layer 12. A heating element is provided on the stopper layer 12 and the protective film 18.
The slits 19 are provided on both sides of the fifteen. The substrate 11 is formed with a recess 20 reaching the stopper layer by etching from the back surface, and communicates with the slit 19.
上記流速センサの製造は、第３図に示すようにして行
う。まず、第３図（ａ）のように、ｐ型シリコンからな
る半導体基板11の表面及び裏面に、熱酸化法、CVD又は
スパツタなどによる絶縁層（SiO2、Si3N4など）からな
るストツパ層12及び絶縁層13を形成する。The flow velocity sensor is manufactured as shown in FIG. First, as shown in FIG. 3 (a), a stopper made of an insulating layer (SiO 2 , Si 3 N 4, etc.) formed by thermal oxidation, CVD, or sputtering is formed on the front and back surfaces of the semiconductor substrate 11 made of p-type silicon. The layer 12 and the insulating layer 13 are formed.
次に第３図（ｂ）のように、ストツパ層12上に蒸着、
スパツタ、CVDなどにより白金（Pt）、ニツケルなどの
金属層を形成し、ホトエツチングなどによりパターン化
し、温度検出素子14、発熱素子15を形成する。双方の素
子14、15にはトリミング溝14a、15aが設けられ、抵抗値
を調整している。各素子14、15に電極16、17を設ける。Next, as shown in FIG. 3 (b), vapor deposition is performed on the stopper layer 12,
A metal layer such as platinum (Pt) or nickel is formed by sputtering, CVD or the like, and patterned by photoetching or the like to form the temperature detecting element 14 and the heat generating element 15. Trimming grooves 14a and 15a are provided in both elements 14 and 15 to adjust the resistance value. Electrodes 16, 17 are provided on each element 14, 15.
第３図（Ｃ）のように、各素子14、15及びストツパ層
12をCVDなどによる保護膜（SiO2、Si3N4）18で覆う。As shown in FIG. 3C, each element 14, 15 and stopper layer
12 is covered with a protective film (SiO 2 , Si 3 N 4 ) 18 formed by CVD or the like.
つづいて、第３図（ｄ）のように上方からホトエツチ
ングによりストツプ層12と保護膜18に、発熱素子15の両
側位置にスリツト19を設ける。電極16、17部上の保護膜
18は除去する。また、絶縁層13を下方からホトエツチン
グにより、発熱素子15及び両スリツト19にまたがる範囲
の下方位置を開口する。Subsequently, as shown in FIG. 3 (d), the slits 19 are provided on the stop layer 12 and the protective film 18 on both sides of the heating element 15 by photo-etching from above. Protective film on electrodes 16 and 17
18 is removed. Further, the insulating layer 13 is photoetched from below so as to open a lower position in a range extending over the heating element 15 and both slits 19.
ついで、第２図に示すように、半導体基板11を裏面か
らエツチングし、ストツパ層12に達する凹部20を形成
し、両スリツト19に連通させる。Then, as shown in FIG. 2, the semiconductor substrate 11 is etched from the back surface to form a recess 20 reaching the stopper layer 12 and communicated with both slits 19.
温度検出素子14及び発熱素子15は抵抗温度係数の大き
い白金、又はニツケルなどからなり、発熱素子15は温度
検出素子14より一定温度高い温度になるよう電気回路が
構成されている。発熱素子15から流体への熱伝達量は流
速の関数となるので、発熱素子15に流れる加熱電流を検
出することで、流通の測定が実現できる。The temperature detecting element 14 and the heating element 15 are made of platinum or nickel having a large temperature coefficient of resistance, and the heating element 15 has an electric circuit configured to have a temperature higher than the temperature detecting element 14 by a constant temperature. Since the amount of heat transferred from the heat generating element 15 to the fluid is a function of the flow velocity, by measuring the heating current flowing through the heat generating element 15, the flow measurement can be realized.
上記基板11はエツチングにより凹部20部がストツパ層
12に達した正確な深さに形成され、上部の薄厚さのスト
ツプ層12と保護膜18とに発熱素子15が挾まれており、両
側にはスリツト19が設けられている。これにより、発熱
素子15に対する横方向の熱抵抗が極めて大きくなり、発
熱素子15の熱容量が小さくてよくなる。The recessed portion 20 of the substrate 11 is a stopper layer due to etching.
The heating element 15 is formed to a precise depth of 12 and is sandwiched by the upper thin stop layer 12 and the protective film 18, and the slits 19 are provided on both sides. Thereby, the thermal resistance in the lateral direction with respect to the heat generating element 15 becomes extremely large, and the heat capacity of the heat generating element 15 can be small.
なお上記実施例では、ストツパ層12上の温度検出素子
14、発熱素子15は金属材の付着によつたが、これに限ら
ず、ストツパ層上に単結晶シリコン層を形成し、このシ
リコン層にポロンイオン注入などにより拡散抵抗を形成
し、この拡散抵抗を温度検出素子及び発熱素子にし、他
の部分のシリコン層はエツチング除去してもよい。In the above embodiment, the temperature detecting element on the stopper layer 12
14, the heating element 15 is based on the adhesion of a metal material, but not limited to this, a single crystal silicon layer is formed on the stopper layer, and a diffusion resistance is formed by polon ion implantation in this silicon layer. May be used as the temperature detecting element and the heat generating element, and the silicon layer in other portions may be removed by etching.
また、上記実施例では温度検出素子14を１個設けた
が、発熱素子15から接近した位置と遠ざかつた位置との
２個を設けた場合にも適用できるものである。Further, although one temperature detecting element 14 is provided in the above embodiment, the present invention can be applied to a case where two elements are provided, one at a position close to the heating element 15 and one at a position away from the heating element 15.
以上のようにこの発明によれば、半導体基板上に絶縁
層からなるエツチングストツパ層を形成し、この上に温
度検出素子と発熱素子を形成し、これらの素子を保護膜
で覆い、上記半導体基板を裏面からエツチングによりス
トツパ層に達する凹部を形成し、保護膜とストツパ層
に、発熱素子の両側位置にスリツトを設け凹部に連通さ
せたので、発熱素子に対する横方向の熱抵抗が極めて大
きくなり、発熱素子の熱容量が小さくでき、温度検出素
子への熱伝導損失が減少され、ドリフトが小さく応答性
が向上され、発熱素子から横方向への熱伝導損失が減少
し、流速感度が増大される。また、消費電力が低減され
る。As described above, according to the present invention, an etching stopper layer made of an insulating layer is formed on a semiconductor substrate, a temperature detecting element and a heating element are formed on the etching stopper layer, and these elements are covered with a protective film. The substrate is etched from the back to form a recess that reaches the stopper layer, and the protective film and the stopper layer are provided with slits on both sides of the heating element so that they communicate with the recess, so the lateral thermal resistance to the heating element becomes extremely large. , The heat capacity of the heating element can be reduced, the heat conduction loss to the temperature detecting element is reduced, the drift is small and the response is improved, the heat conduction loss from the heating element in the lateral direction is reduced, and the flow velocity sensitivity is increased. . In addition, power consumption is reduced.
第１図及び第２図はこの発明による半導体流速センサの
一実施例の平面図及び正面断面図、第３図は第１図の流
速センサの製造方法を工程順に示す説明図、第４図及び
第５図は従来の半導体流速センサの平面図及び正面断面
図である。 図中、11は半導体基板、12はエツチングストツパ層、14
は温度検出素子、15は発熱素子、18は保護膜、19はスリ
ツト、20は凹部である。 尚、図中同一符号は同一または相当部分を示す。1 and 2 are a plan view and a front sectional view of an embodiment of a semiconductor flow velocity sensor according to the present invention, and FIG. 3 is an explanatory view showing a method of manufacturing the flow velocity sensor of FIG. FIG. 5 is a plan view and a front sectional view of a conventional semiconductor flow velocity sensor. In the figure, 11 is a semiconductor substrate, 12 is an etching stopper layer, and 14
Is a temperature detecting element, 15 is a heating element, 18 is a protective film, 19 is a slit, and 20 is a recess. In the drawings, the same reference numerals indicate the same or corresponding parts.
Claims (1)
面に形成された半導体基板、上記ストツパ層上に形成さ
れ、相互が流体の流れ方向に間隔をあけて配置された発
熱素子と少なくとも１個の温度検出素子、これらの素子
及び上記ストツパ層を覆つて形成された保護膜を備え、
上記半導体基板は、裏面から上記発熱素子に対応する位
置にエツチングにより上記ストツパ層に達する深さの凹
部が設けられ、上記保護膜とストツパ層には、上記発熱
素子の両側位置にスリツトを設け上記凹部に連通させた
ことを特徴とする半導体流速センサ。1. A semiconductor substrate having an etching stopper layer made of an insulating layer formed on an upper surface thereof, and at least one heating element formed on the stopper layer and spaced from each other in a fluid flow direction. A temperature detecting element, a protective film formed to cover these elements and the stopper layer,
The semiconductor substrate is provided with a recess having a depth reaching the stopper layer from the back surface at a position corresponding to the heating element by etching, and the protective film and the stopper layer are provided with slits on both sides of the heating element. A semiconductor flow velocity sensor characterized by being communicated with a recess.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP63133080A JP2518352B2 (en) | 1988-05-30 | 1988-05-30 | Semiconductor flow velocity sensor |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP63133080A JP2518352B2 (en) | 1988-05-30 | 1988-05-30 | Semiconductor flow velocity sensor |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPH01301121A JPH01301121A (en) | 1989-12-05 |
| JP2518352B2 true JP2518352B2 (en) | 1996-07-24 |
Family
ID=15096381
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP63133080A Expired - Fee Related JP2518352B2 (en) | 1988-05-30 | 1988-05-30 | Semiconductor flow velocity sensor |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP2518352B2 (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6450025B1 (en) | 1998-03-20 | 2002-09-17 | Denso Corporation | Micro-heater and airflow sensor using the same |
-
1988
- 1988-05-30 JP JP63133080A patent/JP2518352B2/en not_active Expired - Fee Related
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US6450025B1 (en) | 1998-03-20 | 2002-09-17 | Denso Corporation | Micro-heater and airflow sensor using the same |
Also Published As
| Publication number | Publication date |
|---|---|
| JPH01301121A (en) | 1989-12-05 |
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| Date | Code | Title | Description |
|---|---|---|---|
| LAPS | Cancellation because of no payment of annual fees |