JP2005327859A - Magnetoresistive element and revolution detector - Google Patents

Magnetoresistive element and revolution detector Download PDF

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JP2005327859A
JP2005327859A JP2004143857A JP2004143857A JP2005327859A JP 2005327859 A JP2005327859 A JP 2005327859A JP 2004143857 A JP2004143857 A JP 2004143857A JP 2004143857 A JP2004143857 A JP 2004143857A JP 2005327859 A JP2005327859 A JP 2005327859A
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phase
rotation detector
magnetoresistive element
thin film
detector according
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JP4240306B2 (en
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Kazuhiro Nishimura
和浩 西村
Ichiro Shibazaki
一郎 柴崎
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Asahi Kasei Corp
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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L2224/00—Indexing scheme for arrangements for connecting or disconnecting semiconductor or solid-state bodies and methods related thereto as covered by H01L24/00
    • H01L2224/01—Means for bonding being attached to, or being formed on, the surface to be connected, e.g. chip-to-package, die-attach, "first-level" interconnects; Manufacturing methods related thereto
    • H01L2224/42—Wire connectors; Manufacturing methods related thereto
    • H01L2224/47—Structure, shape, material or disposition of the wire connectors after the connecting process
    • H01L2224/48—Structure, shape, material or disposition of the wire connectors after the connecting process of an individual wire connector
    • H01L2224/4805—Shape
    • H01L2224/4809—Loop shape
    • H01L2224/48091—Arched
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L2224/00—Indexing scheme for arrangements for connecting or disconnecting semiconductor or solid-state bodies and methods related thereto as covered by H01L24/00
    • H01L2224/01—Means for bonding being attached to, or being formed on, the surface to be connected, e.g. chip-to-package, die-attach, "first-level" interconnects; Manufacturing methods related thereto
    • H01L2224/42—Wire connectors; Manufacturing methods related thereto
    • H01L2224/47—Structure, shape, material or disposition of the wire connectors after the connecting process
    • H01L2224/48—Structure, shape, material or disposition of the wire connectors after the connecting process of an individual wire connector
    • H01L2224/481—Disposition
    • H01L2224/48151—Connecting between a semiconductor or solid-state body and an item not being a semiconductor or solid-state body, e.g. chip-to-substrate, chip-to-passive
    • H01L2224/48221—Connecting between a semiconductor or solid-state body and an item not being a semiconductor or solid-state body, e.g. chip-to-substrate, chip-to-passive the body and the item being stacked
    • H01L2224/48245—Connecting between a semiconductor or solid-state body and an item not being a semiconductor or solid-state body, e.g. chip-to-substrate, chip-to-passive the body and the item being stacked the item being metallic
    • H01L2224/48247—Connecting between a semiconductor or solid-state body and an item not being a semiconductor or solid-state body, e.g. chip-to-substrate, chip-to-passive the body and the item being stacked the item being metallic connecting the wire to a bond pad of the item

Abstract

<P>PROBLEM TO BE SOLVED: To provide a high sensitivity magnetoresistive element in which variation in resistance and temperature dependency are suppressed, and to provide a revolution detector employing the magnetoresistive element and exhibiting both high detection accuracy and stabilized temperature dependency. <P>SOLUTION: A three terminal magnetoresistive element 11 is formed on an insulating substrate 17 while having a magnetism-sensitive part 18 formed by epitaxially growing an InSb thin film doped with Sn as impurity and exhibiting high electron mobility using an MBE method, and a protective film 21 composed of an insulation layer of an inorganic material is formed on the thin film. Upper side of the magnetism-sensitive part 18, for example, is covered with a soft resin layer 22 of silicon resin or rubber-based resin and the magnetoresistive element 11 is produced by molding the entirety with mold resin 25. A revolution detector of a rotator, e.g. a gear, is manufactured using the magnetoresistive element 11. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

本発明は、化合物半導体薄膜から成る感磁部を有する磁気抵抗素子とこの磁気抵抗素子を用いて回転体の回転を検出する回転検出器に関するものである。   The present invention relates to a magnetoresistive element having a magnetosensitive portion made of a compound semiconductor thin film and a rotation detector that detects the rotation of a rotating body using the magnetoresistive element.

従来、磁気抵抗素子を用いた回転検出器としては、図３７に示すような構造のものが提案されている。同図において、１は磁性体から成る歯車、２は歯車１の回転を検出する磁気抵抗素子、３はこの磁気抵抗素子２に垂直な磁界（バイアス磁界）を印加する永久磁石で、磁気抵抗素子２としては、ＩｎＳｂバルクや真空蒸着法により形成した薄膜などが用いられている（例えば、特許文献１参照）。
ところで、歯車１の回転を検出する際は、一般的には、２個の磁気抵抗素子を直列に接続した３端子の磁気抵抗素子（単相出力）、あるいは、４個の磁気抵抗素子をループ状に接続した４端子の磁気抵抗素子（Ａ相／Ｂ相の２相出力）が使用される。３端子の磁気抵抗素子では、図３８に示すように歯車１の山と谷とに、２個の磁気抵抗素子２ａ，２ｂをそれぞれ合わせて配置する。また、４端子の磁気抵抗素子では、図３９に示すように、歯車１の山と谷にあわせて２個の磁気抵抗素子２ａ，２ｂを直列に配置したもの（Ａ相）と、その１／４周期ずれた位置に２個の磁気抵抗素子２ｃ，２ｄを直列に配置したもの（Ｂ相）が含まれている。そして、それぞれに、直流電源４を接続し、出力端子５，５ａ，５ｂの電位をそれぞれ出力電圧として取出すようにしている。
このような方式による磁気センサ回路の出力信号ｅは、例えば、図３８の場合には、磁気抵抗素子２ａ，２ｂのそれぞれの抵抗値をＲａ，Ｒｂ、直流電源４の電圧をＶｉｎとすれば、出力端子５の電位は、ｅ＝｛（Ｒｂ／（Ｒａ＋Ｒｂ）｝×Ｖｉｎとなる（例えば、特許文献２，３参照）。
特開平３−２５９５７８号公報 特開昭５２−７３７９３号公報 特開昭５２−７３７９４号公報 Conventionally, a rotation detector using a magnetoresistive element has been proposed as shown in FIG. In the figure, 1 is a gear made of a magnetic material, 2 is a magnetoresistive element for detecting the rotation of the gear 1, and 3 is a permanent magnet for applying a magnetic field (bias magnetic field) perpendicular to the magnetoresistive element 2. 2 is an InSb bulk or a thin film formed by a vacuum deposition method (see, for example, Patent Document 1).
By the way, when detecting the rotation of the gear 1, in general, a three-terminal magnetoresistive element (single-phase output) in which two magnetoresistive elements are connected in series, or four magnetoresistive elements are looped. A four-terminal magnetoresistive element (A-phase / B-phase output) is used. In the three-terminal magnetoresistive element, as shown in FIG. 38, two magnetoresistive elements 2a and 2b are respectively arranged at the crest and trough of the gear 1. Further, in the four-terminal magnetoresistive element, as shown in FIG. 39, two magnetoresistive elements 2a and 2b arranged in series in accordance with the crest and trough of the gear 1 (A phase), A device in which two magnetoresistive elements 2c and 2d are arranged in series at a position shifted by four cycles (B phase) is included. Then, a DC power source 4 is connected to each, and the potentials of the output terminals 5, 5a, 5b are respectively taken out as output voltages.
The output signal e of the magnetic sensor circuit according to this method, for example, in the case of FIG. 38, the magnetic resistance element 2a, the respective resistance values of the 2b R a, and R b, the voltage of the DC power supply 4 V in Then, the potential of the output terminal 5 becomes e = {(R b / (R a + R b )} × V in (see, for example, Patent Documents 2 and 3).
JP-A-3-259578 JP 52-73793 A JP-A-52-73794

ところで、従来のＩｎＳｂ磁気抵抗素子においては、感磁部を形成するＩｎＳｂは抵抗率が１℃当たり約２％と大きな温度依存性を有し、周辺温度や動作に関わる電流通電などによる発熱のため、磁気抵抗素子の抵抗値が変化するという問題があり、これが原因で、出力電圧が変動することも多かった。
上記のような周囲温度の変化等に起因する各種のノイズに関しては、２個の磁気抵抗素子２ａ，２ｂが空間的に近接して配置されているので、両者の受ける温度的、磁気的、または機械的原因による磁気抵抗素子２ａ，２ｂの抵抗変動分ΔＲａとΔＲｂとは等しいと考えることができる。したがって、ノイズ成分に関してはΔｅ＝０となるはずである。
しかしながら、これは、磁気抵抗素子２ａ，２ｂの抵抗値ＲａとＲｂとが等しいことが前提条件となる。一般的には、磁気抵抗素子２ａの抵抗値と磁気抵抗素子２ｂの抵抗値とは異なる場合が多く、その上、磁気抵抗素子２ａと磁気抵抗素子２ｂの抵抗値の温度係数は異なっていることが多い。したがって、ＲａとＲｂが等しい場合は、出力端子の電位は、Ｖｉｎ／２となりかつノイズ成分もなくなるが、ＲａとＲｂとが等しくない場合、あるいは抵抗値の温度係数が異なる場合にはノイズ成分も出力されるだけでなく、出力端子５の電位は、ｅ＝Ｖｉｎ／２からずれてしまい、周囲の温度が変化すれば温度ドリフトも生じることになる。 By the way, in the conventional InSb magnetoresistive element, the InSb forming the magnetic sensitive part has a large temperature dependency of about 2% per 1 ° C., and is due to heat generation due to ambient current and current conduction related to operation. However, there is a problem that the resistance value of the magnetoresistive element changes, and this often causes the output voltage to fluctuate.
With respect to various noises caused by changes in the ambient temperature as described above, the two magnetoresistive elements 2a and 2b are arranged spatially close to each other, so that both the thermal, magnetic, or magnetoresistive elements 2a due to mechanical causes, can be considered to be equal to the resistance variation [Delta] R a and [Delta] R b of 2b. Therefore, Δe = 0 should be obtained for the noise component.
However, this is a precondition that the resistance values Ra and Rb of the magnetoresistive elements 2a and 2b are equal. In general, the resistance value of the magnetoresistive element 2a is often different from the resistance value of the magnetoresistive element 2b, and the temperature coefficient of the resistance value of the magnetoresistive element 2a is different from that of the magnetoresistive element 2b. There are many. Thus, when R a and R b are equal, the potential of the output terminal, V in / 2 and becomes and the noise component is also eliminated, but if not equal the R a and R b, or if the temperature coefficient of resistance is different In addition to outputting a noise component, the potential of the output terminal 5 deviates from e = V in / 2, and if the ambient temperature changes, a temperature drift also occurs.

また、磁気抵抗素子は、これまではバルク単結晶ＩｎＳｂを厚さ数μｍから十数μｍに薄く研磨して製作されたものが多く用いられていた。上記のようなバルク単結晶ＩｎＳｂの磁気抵抗素子２を製作する際には、研磨によりバルク単結晶ＩｎＳｂを薄く加工し、更に、微細な加工を行って所望の形状にする必要があるが、研磨で製作したバルク単結晶ＩｎＳｂは標準的な半導体の微細加工技術の適用が難しいため、その平面的な加工精度はもとより、最も重要な研磨による厚さの制御が困難であった。そのため、製品の特性、特に、ＩｎＳｂの厚さのばらつきや平面的な加工精度の大きなばらつきがあると、磁気抵抗素子２の抵抗値や感度が、厚さや加工精度のばらつきに連動してしまうため、安定した特性が得られないといった問題点があった。
すなわち、従来のバルク単結晶ＩｎＳｂを薄く研磨して製作された磁気抵抗素子では、磁気抵抗素子２ａ，２ｂの抵抗値が異なり、かつ抵抗値の温度係数も異なることが多く、そのため、出力端子５の電位は、ｅ＝Ｖｉｎ／２からずれており、上記電位ｅの温度ドリフトも非常に大きかった。 In the past, many magnetoresistive elements were manufactured by polishing bulk single crystal InSb thinly from several μm to several tens of μm. When manufacturing the magnetoresistive element 2 of the bulk single crystal InSb as described above, it is necessary to thinly process the bulk single crystal InSb by polishing and further perform fine processing to obtain a desired shape. Since the bulk single crystal InSb manufactured by the method described above is difficult to apply a standard semiconductor microfabrication technique, it is difficult to control the thickness by the most important polishing as well as the planar processing accuracy. For this reason, if there is a variation in product characteristics, particularly InSb thickness or a large variation in planar processing accuracy, the resistance value and sensitivity of the magnetoresistive element 2 are linked to variations in thickness and processing accuracy. There is a problem that stable characteristics cannot be obtained.
That is, in the conventional magnetoresistive element manufactured by thinly polishing the bulk single crystal InSb, the resistance values of the magnetoresistive elements 2a and 2b are different and the temperature coefficient of the resistance value is often different. the potentials are offset from e = V in / 2, the temperature drift of the potential e was also very large.

ところで、磁気抵抗素子の磁気抵抗効果は以下の式で記述できる。
ΔＲ／Ｒ０∝（μＢ）２ ：低印加磁界時 ‥‥‥‥（１）
ΔＲ／Ｒ０∝（μＢ） ：高印加磁界時 ‥‥‥‥（２）
但し、ΔＲ＝ＲＢ−Ｒ０であり、ＲＢは磁界中での抵抗値、Ｒ０は磁場なしでの抵抗値、μは電子移動度、Ｂは印加磁界である。
式（１），（２）より、出力信号の振幅は、電子移動度μに依存することになる。従来のバルク単結晶ＩｎＳｂを薄く研磨して製作された磁気抵抗素子は、電子移動度μの温度依存性も大きく、図４０に示す出力信号振幅Ａの温度依存性が大であった。
一方、磁気抵抗素子を真空蒸着法により形成した場合も、膜厚や組成のばらつきが多く磁気抵抗素子２ａ，２ｂの素子特性を揃えることが困難なだけでなく、また、十分な電子移動度が得られず、また、その温度依存性も大きかった。
また、磁気抵抗素子は、通常、エポキシ樹脂等の硬質樹脂でモールドされる。この硬質樹脂による応力には以下のものがある。
・比較的高温でモールドが行われるために、モールド後、硬質樹脂が室温に下がったときの熱収縮からくる応力
・素子周囲の温度が変化した時に、硬質樹脂と半導体薄膜の熱膨張率が異なることによる応力
がある。更に、熱収縮による応力分布が不均一であるために、感磁部に一様に応力が加わらないことから、薄膜の温度特性が不均一になることが多かった。 Incidentally, the magnetoresistive effect of the magnetoresistive element can be described by the following equation.
ΔR / R 0 ∝ (μB) 2 : At low applied magnetic field (1)
ΔR / R 0 α (μB) : High magnetic field (2)
However, a ΔR = R B -R 0, R B is the resistance in the magnetic field, R 0 is the resistance with no magnetic field, mu is the electron mobility, B is the applied magnetic field.
From the equations (1) and (2), the amplitude of the output signal depends on the electron mobility μ. A magnetoresistive element manufactured by thinly polishing a conventional bulk single crystal InSb has a large temperature dependence of the electron mobility μ, and the temperature dependence of the output signal amplitude A shown in FIG. 40 is large.
On the other hand, when the magnetoresistive element is formed by a vacuum deposition method, not only is it difficult to align the element characteristics of the magnetoresistive elements 2a and 2b because of variations in film thickness and composition, and sufficient electron mobility is obtained. It was not obtained, and the temperature dependency was large.
The magnetoresistive element is usually molded with a hard resin such as an epoxy resin. The stress due to this hard resin includes the following.
・ Since the molding is performed at a relatively high temperature, the thermal expansion coefficient of the hard resin differs from that of the semiconductor thin film when the temperature around the element changes after the molding. There is stress due to. Furthermore, since the stress distribution due to heat shrinkage is not uniform, the stress is not uniformly applied to the magnetically sensitive portion, so that the temperature characteristics of the thin film often become nonuniform.

本発明は、従来の問題点に鑑みてなされたもので、高感度で、かつ、抵抗値のばらつきや温度依存性が小さな磁気抵抗素子と、この磁気抵抗素子を用いた高い検出精度と安定した温度依存性とを併せ持った回転検出器を提供することを目的とする。   The present invention has been made in view of the conventional problems, and has a high sensitivity, a resistance value variation and a small temperature dependence, and a high detection accuracy and a stable using the magnetoresistance element. An object of the present invention is to provide a rotation detector having both temperature dependence.

本発明者は、歯車等の回転体の回転を検出する回転検出器について、
・微細加工精度の優れた高感度の化合物半導体薄膜材料開発とその温度特性の低減技術
・素子特性のばらつきを抑えるための高度な化合物半導体薄膜の膜厚制御技術及び均一性の高い不純物のドープ技術
・歯車回転の高感度／高精度検出が可能でかつ高信頼性な素子構造
・低コストの量産プロセス技術
・高信頼性のモジュール（組立体）構造
の開発に取り組んだ結果、微細加工精度に優れた、膜厚均一性の良い薄膜材料の開発、面内均一性の高い不純物のドープ技術、高い電子移動度を得る薄膜の単結晶成長技術、高感度／高精度検出が可能で高信頼性な素子構造、信頼性の高いモジュール（組立体）構造、バイアス磁界印加手段などの複数の技術を開発し、更に、これらを適切に、かつ最適化した構成で組み合わせることで、回転体の回転を高精度に検出可能とした化合物半導体薄膜を感磁部（磁気検出部）に採用した、量産性に優れ、特性のばらつきの少ない高性能な回転検出器を得ることができることを見いだし、本発明に到ったものである。
すなわち、本発明の請求項１に記載の発明は、絶縁基板上に形成された化合物半導体薄膜から成る感磁部と、この感磁部に形成された複数の端子電極とを備えた磁気抵抗素子であって、前記化合物半導体薄膜にドナー不純物をドープするとともに、前記感磁部の上部側を、直接または間接に覆う軟質樹脂層を設けたことを特徴とするものである。 The inventor of the present invention has a rotation detector that detects rotation of a rotating body such as a gear.
・ Development of highly sensitive compound semiconductor thin film materials with excellent microfabrication accuracy and technology for reducing temperature characteristics ・ Advanced compound semiconductor thin film thickness control technology and highly uniform impurity doping technology to suppress variations in device characteristics・ Highly reliable / high-precision detection of gear rotation and high-reliability element structure ・ Low-cost mass-production process technology ・ High-reliability module (assembly) structure development results in excellent micromachining accuracy Development of thin film materials with good film thickness uniformity, impurity doping technology with high in-plane uniformity, single crystal growth technology for thin film with high electron mobility, high sensitivity / high accuracy detection and high reliability Developed multiple technologies such as element structure, highly reliable module (assembly) structure, bias magnetic field application means, etc., and combined them with appropriate and optimized configurations to rotate the rotating body We have found that a compound semiconductor thin film that can be detected with high precision is adopted in the magnetic sensing part (magnetic detection part), and that it is possible to obtain a high-performance rotation detector with excellent mass productivity and little variation in characteristics. It has arrived.
That is, the invention according to claim 1 of the present invention is a magnetoresistive element including a magnetic sensing portion made of a compound semiconductor thin film formed on an insulating substrate and a plurality of terminal electrodes formed on the magnetic sensing portion. The compound semiconductor thin film is doped with a donor impurity and is provided with a soft resin layer that directly or indirectly covers the upper side of the magnetically sensitive portion.

また、請求項２に記載の発明は、絶縁基板上に形成された感磁部及びこの感磁部に形成された複数の端子電極を備えた磁気抵抗素子と、前記磁気抵抗素子に磁界を印加する手段とを備え、前記磁界を変化させる回転体の回転状態を検出する回転検出器であって、前記化合物半導体薄膜にドナー不純物をドープするとともに、前記感磁部の上部側を、直接または間接に覆う軟質樹脂層を設けたことを特徴とするものである。
請求項３に記載の回転検出器は、前記軟質樹脂層をシリコン樹脂、または、ゴム系樹脂より構成したものである。
請求項４に記載の回転検出器は、前記化合物半導体薄膜の厚さを、０．１〜４．０μｍとしたものである。
請求項５に記載の回転検出器は、前記軟質樹脂層の厚さを、１〜３００μｍしたものである。
請求項６に記載の回転検出器は、前記軟質樹脂層の上部側を、表面が前記感磁部面に対して平行面となるように、硬質樹脂層により覆うようにしたものである。 According to a second aspect of the present invention, there is provided a magnetoresistive element comprising a magnetosensitive part formed on an insulating substrate and a plurality of terminal electrodes formed on the magnetosensitive part, and applying a magnetic field to the magnetoresistive element. And a rotation detector for detecting a rotation state of the rotating body that changes the magnetic field, wherein the compound semiconductor thin film is doped with a donor impurity, and the upper side of the magnetosensitive portion is directly or indirectly A soft resin layer that covers the surface is provided.
In the rotation detector according to a third aspect, the soft resin layer is made of silicon resin or rubber resin.
In the rotation detector according to a fourth aspect of the present invention, the thickness of the compound semiconductor thin film is 0.1 to 4.0 μm.
In the rotation detector according to claim 5, the thickness of the soft resin layer is 1 to 300 μm.
In the rotation detector according to a sixth aspect of the invention, the upper side of the soft resin layer is covered with a hard resin layer so that the surface thereof is parallel to the magnetic sensitive surface.

また、請求項７に記載の回転検出器は、前記化合物半導体薄膜上に絶縁性無機質材料から成る保護層を設け、この保護層の上に前記軟質樹脂層を形成したものである。
請求項８に記載の回転検出器は、前記感磁面における磁束密度を、前記感磁部の抵抗値の変化率が５０％以上となる磁束密度としたものである。 In the rotation detector according to claim 7, a protective layer made of an insulating inorganic material is provided on the compound semiconductor thin film, and the soft resin layer is formed on the protective layer.
In the rotation detector according to an eighth aspect of the present invention, the magnetic flux density at the magnetic sensitive surface is a magnetic flux density at which the rate of change of the resistance value of the magnetic sensitive portion is 50% or more.

また、請求項９に記載の回転検出器は、前記感磁部の全面に渉り、磁界の印加された状態での抵抗値の温度依存性の均一性が±１．０％以内であることを特徴とするものである。
請求項１０に記載の回転検出器は、前記硬質樹脂層の上に、厚さが０．５ｍｍ以下の金属薄板を配置したものである。
請求項１１に記載の回転検出器は、前記磁界印加手段をＳｍＣｏ磁石としたものである。 Further, in the rotation detector according to claim 9, the uniformity of the temperature dependence of the resistance value in a state where a magnetic field is applied is within ± 1.0% over the entire surface of the magnetic sensing portion. It is characterized by.
In the rotation detector according to claim 10, a thin metal plate having a thickness of 0.5 mm or less is disposed on the hard resin layer.
In a rotation detector according to an eleventh aspect, the magnetic field applying means is an SmCo magnet.

請求項１２に記載の回転検出器は、前記感磁部を形成する化合物半導体薄膜を、単結晶ＩｎＡｓxＳｂ1-x（０≦ｘ≦１）薄膜としたことを特徴とするものである。
請求項１３に記載の回転検出器は、前記絶縁基板の表面に高抵抗層または絶縁層を設け、この上に前記化合物半導体薄膜を形成したものである。
請求項１４に記載の回転検出器は、前記化合物半導体薄膜を単結晶ＩｎＳｂ薄膜とするとともに、前記高抵抗層または絶縁層を前記薄膜の結晶構造と同一の結晶構造を有する高抵抗層または絶縁層としたものである。
請求項１５に記載の回転検出器は、前記化合物半導体薄膜を単結晶ＩｎＳｂ薄膜とするとともに、前記高抵抗層または絶縁層と前記薄膜との格子定数の差を２．０％以下としたものである。
請求項１６に記載の回転検出器は、前記ドープするドナー不純物を、Ｓｉ，Ｓｎ，Ｓ，Ｓｅ，Ｔｅ，Ｇｅ，Ｃから選ばれる少なくとも１つまたは複数としたものである。 The rotation detector according to a twelfth aspect is characterized in that the compound semiconductor thin film forming the magnetosensitive portion is a single crystal InAs x Sb 1-x (0 ≦ x ≦ 1) thin film.
According to a thirteenth aspect of the present invention, there is provided a rotation detector in which a high resistance layer or an insulating layer is provided on the surface of the insulating substrate, and the compound semiconductor thin film is formed thereon.
15. The rotation detector according to claim 14, wherein the compound semiconductor thin film is a single crystal InSb thin film, and the high resistance layer or insulating layer has a crystal structure identical to the crystal structure of the thin film. It is what.
The rotation detector according to claim 15, wherein the compound semiconductor thin film is a single crystal InSb thin film, and a difference in lattice constant between the high resistance layer or the insulating layer and the thin film is 2.0% or less. is there.
In a rotation detector according to a sixteenth aspect of the present invention, the donor impurity to be doped is at least one or more selected from Si, Sn, S, Se, Te, Ge, and C.

請求項１７に記載の回転検出器は、請求項２に記載の回転検出器において、外部接続用の３個の端子電極を有し、２個の磁気抵抗素子が直列に接続された３端子磁気抵抗素子から構成された磁気検出部を備え、前記端子から、Ａ相またはＢ相の非差動出力を得るようにしたものである。
請求項１８に記載の回転検出器は、請求項２に記載の回転検出器において、外部接続用の４個の端子電極を有し、４個の磁気抵抗素子がフルブリッジ構造に接続された４端子の磁気抵抗素子から構成された磁気検出部を備え、前記端子から、Ａ相／Ｂ相の非差動２出力を得るようにしたものである。
請求項１９に記載の回転検出器は、請求項２に記載の回転検出器において、外部接続用の４個の端子電極を有し、４個の磁気抵抗素子がフルブリッジ構造に接続された４端子磁気抵抗素子から構成され、かつ、互いに隣接して接続されていない２対の磁気抵抗素子がそれぞれ同相の磁界変化を受けるように前記各磁気抵抗素子を配置して成る磁気検出部を備え、前記端子から、Ａ相／Ａ−相、あるいは、Ｂ相／Ｂ−相の差動単相出力を得るようにしたものである。
請求項２０に記載の回転検出器は、請求項２に記載の回転検出器において、外部接続用の４個の端子電極を有し、４個の磁気抵抗素子がフルブリッジ構造に接続された４端子磁気抵抗素子から構成され、かつ、互いに隣接して接続されていない２対の磁気抵抗素子が同相の磁界変化を受けるように前記各磁気抵抗素子を配置して成る２組の磁気検出部を備え、１組の磁気抵抗素子からはＡ相／Ａ−相の、もう１組の磁気抵抗素子からはＢ相／Ｂ−相の差動２相出力を得るようにしたものである。 The rotation detector according to claim 17 is the rotation detector according to claim 2, wherein the rotation detector has three terminal electrodes for external connection, and two magnetoresistive elements are connected in series. A magnetic detection unit constituted by a resistance element is provided, and an A-phase or B-phase non-differential output is obtained from the terminal.
The rotation detector according to claim 18 is the rotation detector according to claim 2, wherein the rotation detector has four terminal electrodes for external connection, and four magnetoresistive elements are connected in a full bridge structure. A magnetic detection unit constituted by a magnetoresistive element of a terminal is provided, and two non-differential outputs of A phase / B phase are obtained from the terminal.
The rotation detector according to claim 19 is the rotation detector according to claim 2, wherein the rotation detector has four terminal electrodes for external connection, and four magnetoresistive elements are connected in a full bridge structure. A magnetic detection unit comprising the terminal magnetoresistive elements and arranging the magnetoresistive elements so that two pairs of magnetoresistive elements not connected adjacent to each other receive a change in magnetic field of the same phase; A differential single phase output of A phase / A-phase or B phase / B-phase is obtained from the terminal.
A rotation detector according to claim 20 is the rotation detector according to claim 2, wherein the rotation detector has four terminal electrodes for external connection, and four magnetoresistive elements are connected in a full bridge structure. Two sets of magnetic detectors, each of which is composed of terminal magnetoresistive elements and in which each of the magnetoresistive elements is arranged so that two pairs of magnetoresistive elements that are not connected adjacent to each other receive a change in the magnetic field of the same phase, In addition, a differential two-phase output of A phase / A-phase is obtained from one set of magnetoresistive elements, and a B-phase / B-phase output is obtained from the other set of magnetoresistive elements.

また、請求項２１に記載の回転検出器は、請求項１７に記載の回転検出器において、前記３端子の磁気抵抗素子が１チップ上に形成されていることを特徴とするものである。
請求項２２に記載の回転検出器は、請求項１８に記載の回転検出器において、前記４端子の非差動の磁気抵抗素子が１チップ上に形成されていることを特徴とするものである。
請求項２３に記載の回転検出器は、請求項１９に記載の回転検出器において、前記４端子の差動の磁気抵抗素子が１チップ上に形成されていることを特徴とするものである。
請求項２４に記載の回転検出器は、請求項２０に記載の回転検出器において、前記８個の磁気抵抗素子を有する差動の素子が１チップ上に形成されていることを特徴とするものである。 A rotation detector according to a twenty-first aspect is the rotation detector according to the seventeenth aspect, wherein the three-terminal magnetoresistive element is formed on one chip.
The rotation detector according to claim 22 is the rotation detector according to claim 18, wherein the four-terminal non-differential magnetoresistive element is formed on one chip. .
The rotation detector according to claim 23 is the rotation detector according to claim 19, wherein the four-terminal differential magnetoresistive element is formed on one chip.
A rotation detector according to claim 24 is the rotation detector according to claim 20, wherein the differential element having the eight magnetoresistive elements is formed on one chip. It is.

請求項２５に記載の回転検出器は、請求項１７に記載の回転検出器において、前記３端子の磁気抵抗素子を２個備え、一方をＡ相用とし、他方をＺ相用としたものである。
請求項２６に記載の回転検出器は、請求項１８に記載の回転検出器において、前記４端子の非差動の磁気抵抗素子を２個備え、一方をＡ相／Ｂ相用とし、他方をＺａ相／Ｚｂ相用としたことを特徴とするものである。
請求項２７に記載の回転検出器は、請求項１９に記載の回転検出器において、前記４端子の差動の磁気抵抗素子を３個備え、それぞれ、Ａ相／Ａ−相、Ｂ相／Ｂ−相、Ｚ相／Ｚ−相としたことを特徴とするものである。
請求項２８に記載の回転検出器は、請求項２０に記載の回転検出器において、前記８個の磁気抵抗素子を有する差動の素子を１個と、差動の４端子の磁気抵抗素子を１個備え、それぞれ、Ａ相／Ａ−相、Ｂ相／Ｂ−相、Ｚ相／Ｚ−相としたことを特徴とするものである。 The rotation detector according to claim 25 is the rotation detector according to claim 17, comprising two of the three-terminal magnetoresistive elements, one for the A phase and the other for the Z phase. is there.
A rotation detector according to a twenty-sixth aspect is the rotation detector according to the eighteenth aspect, comprising two of the four-terminal non-differential magnetoresistive elements, one for A-phase / B-phase and the other for It is characterized by being for the Za phase / Zb phase.
A rotation detector according to a twenty-seventh aspect is the rotation detector according to the nineteenth aspect, comprising three differential magnetoresistive elements of the four terminals, which are respectively A phase / A-phase and B phase / B. -Phase, Z-phase / Z-phase.
A rotation detector according to claim 28 is the rotation detector according to claim 20, wherein one differential element having the eight magnetoresistive elements and a differential four-terminal magnetoresistive element are provided. One is provided, and each of them is characterized as A phase / A-phase, B phase / B-phase, and Z phase / Z-phase.

本発明によれば、絶縁基板上に、ドナー不純物をドープした化合物半導体薄膜から成る感磁部と、この感磁部に設けられた複数の端子電極とを有する磁気抵抗素子を形成するとともに、感磁部の上部側を、直接または間接に覆う、例えば、シリコン樹脂、または、ゴム系樹脂から成る軟質樹脂層を設けたので、高い電子移動度を有する薄膜を作製することができるとともに、磁気抵抗素子の抵抗値のばらつきや温度依存性を小さくすることができる。また、モールドでの応力を緩和することができるので、検出感度を向上させることができる。また、この磁気抵抗素子を用いて、回転体の回転を検出するようにしたので、回転の検出精度を高めることができるとともに、回転検出器の温度ドリフトを大幅に低減することができる。
このとき、感磁面における磁束密度を、感磁部の抵抗値の変化率が５０％以上となる磁束密度とすることにより、磁気抵抗素子の感度を更に向上させることができる。
また、化合物半導体薄膜にドナー不純物をドープして感磁部の電子濃度を制御し、感磁部の全面に渉り、磁界の印加された状態での抵抗値の温度依存性の均一性が±１．０％以内となるようにしたので、温度ドリフトを更に低減することができる。 According to the present invention, a magnetoresistive element having a magnetosensitive portion made of a compound semiconductor thin film doped with a donor impurity and a plurality of terminal electrodes provided on the magnetosensitive portion is formed on an insulating substrate. Since a soft resin layer made of, for example, a silicon resin or a rubber-based resin is provided to directly or indirectly cover the upper side of the magnetic part, a thin film having high electron mobility can be produced, and a magnetoresistance Variations in resistance values and temperature dependence of the elements can be reduced. Moreover, since the stress in a mold can be relieved, detection sensitivity can be improved. In addition, since the rotation of the rotating body is detected using this magnetoresistive element, the detection accuracy of the rotation can be increased and the temperature drift of the rotation detector can be greatly reduced.
At this time, the sensitivity of the magnetoresistive element can be further improved by setting the magnetic flux density on the magnetosensitive surface to a magnetic flux density at which the rate of change of the resistance value of the magnetosensitive portion is 50% or more.
In addition, the compound semiconductor thin film is doped with a donor impurity to control the electron concentration in the magnetic sensitive part, and the temperature dependence uniformity of the resistance value in a state where a magnetic field is applied is ±±. Since it is within 1.0%, the temperature drift can be further reduced.

また、感磁部を形成する化合物半導体薄膜を、Ｓｉ，Ｓｎ，Ｓ，Ｓｅ，Ｔｅ，Ｇｅ，Ｃなどのドナー不純物をドープした単結晶ＩｎＡｓxＳｂ1-x（０≦ｘ≦１）薄膜、特に、単結晶ＩｎＳｂ薄膜とすることにより、電子移動度を大きくして検出感度を向上させることができる。
更に、絶縁基板の表面に、化合物半導体薄膜の結晶構造と同一の結晶構造を有する高抵抗層または絶縁層を設け、この高抵抗層または絶縁層の上に化合物半導体薄膜を形成するようにしたので、化合物半導体薄膜の電子移動度の低下を効果的に抑制することができる。このとき、化合物半導体薄膜を単結晶ＩｎＳｂ薄膜とするとともに、高抵抗層または絶縁層と化合物半導体薄膜との格子定数の差を２．０％以下とすれば、高い電子移動度を確実に実現することができる。 In addition, the compound semiconductor thin film that forms the magnetosensitive portion is a single crystal InAs x Sb 1-x (0 ≦ x ≦ 1) thin film doped with donor impurities such as Si, Sn, S, Se, Te, Ge, and C, In particular, by using a single crystal InSb thin film, electron mobility can be increased and detection sensitivity can be improved.
Furthermore, since a high resistance layer or an insulating layer having the same crystal structure as that of the compound semiconductor thin film is provided on the surface of the insulating substrate, the compound semiconductor thin film is formed on the high resistance layer or the insulating layer. Therefore, it is possible to effectively suppress the decrease in electron mobility of the compound semiconductor thin film. At this time, if the compound semiconductor thin film is a single crystal InSb thin film and the difference in lattice constant between the high resistance layer or the insulating layer and the compound semiconductor thin film is 2.0% or less, high electron mobility is reliably realized. be able to.

以下、本発明の実施の形態について、図面に基づき説明する。
［実施の形態１］
図１は、本実施の形態１に係る回転検出器１０の構成を示す断面図で、同図において、１１は絶縁基板上に形成された、抵抗値が磁界によって変化する化合物半導体薄膜から成る感磁部と複数の端子電極を備えた磁気抵抗素子、１２は磁気抵抗素子１１の検出対象である歯車１とは反対側に設けられた、感磁部に垂直にバイアス磁界を印加するための永久磁石、１３は磁気抵抗素子１１に直流電圧を加えたり、磁気抵抗素子１１からの出力を外部に取出すための端子ピン、１４は磁気抵抗素子１１を保護するための薄い金属板、１５は永久磁石１２を保持している磁石ホルダー、１６は磁気抵抗素子１１や永久磁石１２などを収納する円筒状の樹脂ケースである。なお、本例の回転検出器１０の検出対象である歯車１は磁性体から構成されるが、検出部となる歯またはその一部が磁性体であれば、歯車全体が必ずしも磁性体でなくてもよい。
図２は、磁気抵抗素子１１の基本構成を示す図で、この磁気抵抗素子１１は、絶縁性基板１７上に形成された化合物半導体薄膜から成る感磁部１８と、この感磁部１８に接続される端子電極１９と、感磁部１８上に形成された複数の短絡電極２０と、感磁部１８及び短絡電極２０とを覆う無機質材料の絶縁層から成る保護膜２１と、この保護膜２１上に形成された軟質樹脂層２２とを備えた３端子構成の磁気抵抗素子で、この３端子の磁気抵抗素子１１は、詳細には、図３（ａ），（ｂ）に示すように、互いに並行に配置された第１及び第２の磁気抵抗素子１８ａ，１８ｂと、この磁気抵抗素子１８ａ，１８ｂの一方の端部にはそれぞれ設けられた入力端子となる端子電極１９ａ，１９ｂと、磁気抵抗素子１８ａ，１８ｂの他方の端部同士を接続する出力端子となる端子電極１９ｃと、端子電極１９ａと端子電極１９ｃとの間、及び、端子電極１９ｂと端子電極１９ｃとの間に形成された複数の短絡電極２０とを備えている。なお、同図において、１２は上述した磁石ホルダー１５に保持され、３端子の磁気抵抗素子１１の裏面側に配置された永久磁石である。
永久磁石１２としては、フェライト磁石、サマリウムコバルト磁石（ＳｍＣｏ磁石）、ネオジム磁石等があり、残留磁束密度の温度係数は、それぞれ−０．１８％／℃、−０．０３％／℃、−０．１２％／℃である。したがって、温度特性の観点からは、永久磁石１２としては、ＳｍＣｏ磁石が最適である。 Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[Embodiment 1]
FIG. 1 is a cross-sectional view showing the configuration of the rotation detector 10 according to the first embodiment. In FIG. 1, reference numeral 11 denotes a sensitivity formed of a compound semiconductor thin film formed on an insulating substrate and having a resistance value that varies with a magnetic field. A magnetoresistive element having a magnetic part and a plurality of terminal electrodes, 12 is a permanent magnet for applying a bias magnetic field perpendicularly to the magnetic sensitive part provided on the side opposite to the gear 1 which is a detection target of the magnetoresistive element 11. A magnet, 13 is a terminal pin for applying a DC voltage to the magnetoresistive element 11 or taking out an output from the magnetoresistive element 11, 14 is a thin metal plate for protecting the magnetoresistive element 11, and 15 is a permanent magnet. A magnet holder 16 for holding 12 is a cylindrical resin case for housing the magnetoresistive element 11 and the permanent magnet 12. Note that the gear 1 that is the detection target of the rotation detector 10 of this example is made of a magnetic material. However, if the teeth that serve as the detection unit or a part thereof are magnetic, the entire gear is not necessarily a magnetic material. Also good.
FIG. 2 is a diagram showing a basic configuration of the magnetoresistive element 11. The magnetoresistive element 11 is connected to the magnetosensitive part 18 made of a compound semiconductor thin film formed on the insulating substrate 17 and the magnetosensitive element 18. Terminal electrode 19, a plurality of short-circuit electrodes 20 formed on the magnetic sensing part 18, a protective film 21 made of an insulating layer of an inorganic material covering the magnetic sensor part 18 and the short-circuit electrode 20, and the protective film 21 A three-terminal magnetoresistive element having a soft resin layer 22 formed thereon, the three-terminal magnetoresistive element 11 is shown in detail in FIGS. 3 (a) and 3 (b). First and second magnetoresistive elements 18a and 18b arranged in parallel to each other, terminal electrodes 19a and 19b serving as input terminals respectively provided at one end of the magnetoresistive elements 18a and 18b, and magnetic The other ends of the resistance elements 18a and 18b And the terminal electrode 19c serving as an output terminal for connection, comprises between the terminal electrode 19a and the terminal electrode 19c, and a plurality of short-circuit electrodes 20 formed between the terminal electrode 19b and the terminal electrode 19c. In the figure, reference numeral 12 denotes a permanent magnet which is held on the magnet holder 15 and arranged on the back side of the three-terminal magnetoresistive element 11.
As the permanent magnet 12, there are a ferrite magnet, a samarium cobalt magnet (SmCo magnet), a neodymium magnet, etc., and the temperature coefficient of the residual magnetic flux density is -0.18% / ° C, -0.03% / ° C, -0, respectively. 12% / ° C. Therefore, an SmCo magnet is optimal as the permanent magnet 12 from the viewpoint of temperature characteristics.

磁気抵抗素子１１は、端子電極１９ａ，１９ｂ及び端子電極１９ｃとを、例えば、図４に示すように、金ワイヤー２３により、図示しない端子ピン１３に接続されるリードフレーム２４にワイヤーボンドした後、これらをエポキシ樹脂などのモールド樹脂２５によりパッケージされ、永久磁石１２を保持した磁石ホルダー１５とともに円筒状の樹脂ケース１６に収納される。これにより、全体が円柱状である回転検出器１０を得ることができる。
ところで、歯車１等の回転を検出する際には、図５（ａ），（ｂ）に示すように、感磁部１８を構成する化合物半導体薄膜の表面から歯車１までの距離（ギャップ）Ｇが近いほど出力信号は大きくなる。したがって、モールド樹脂２５の上に配置される金属板１４としては、厚さが０．５ｍｍ以下の金属薄板を用いることが好ましく、特に、金属板１４の厚さを０．１５ｍｍ程度とし、化合物半導体薄膜の表面からモールド樹脂２５の表面までの距離を０．２ｍｍ以下になるようにすれは、高い感度を得ることができる。このとき、軟質樹脂層２２の上部側を覆うモールド樹脂２５の表面側を、感磁部面と平行面とすることが肝要である。これにより、歯車１と感磁部１８との距離を確実に一定にすることができ、第１及び第２の磁気抵抗素子１８ａ，１８ｂの感度を揃えることができる。 The magnetoresistive element 11 wire bonds the terminal electrodes 19a and 19b and the terminal electrode 19c to a lead frame 24 connected to a terminal pin 13 (not shown) by a gold wire 23 as shown in FIG. These are packaged with a mold resin 25 such as an epoxy resin, and stored in a cylindrical resin case 16 together with a magnet holder 15 holding the permanent magnet 12. Thereby, the rotation detector 10 whose whole is a column shape can be obtained.
By the way, when detecting the rotation of the gear 1 or the like, as shown in FIGS. 5A and 5B, the distance (gap) G from the surface of the compound semiconductor thin film constituting the magnetic sensitive portion 18 to the gear 1 is shown. The closer the is, the larger the output signal. Therefore, as the metal plate 14 disposed on the mold resin 25, it is preferable to use a metal thin plate having a thickness of 0.5 mm or less. In particular, the thickness of the metal plate 14 is set to about 0.15 mm, and the compound semiconductor is used. If the distance from the surface of the thin film to the surface of the mold resin 25 is 0.2 mm or less, high sensitivity can be obtained. At this time, it is important that the surface side of the mold resin 25 covering the upper side of the soft resin layer 22 is a plane parallel to the magnetic sensitive surface. As a result, the distance between the gear 1 and the magnetic sensing portion 18 can be made constant, and the sensitivity of the first and second magnetoresistive elements 18a and 18b can be made uniform.

磁気抵抗素子１１の感磁部１８を構成する化合物半導体薄膜としては、一般には、周期律表でIII族及びＶ族の元素から成る化合物半導体が用いられる。本発明においては、化合物半導体は、高い磁気抵抗変化率を得るためにできるだけ高い電子移動度を有していることが好ましいことから、化合物半導体薄膜をＩｎＳｂ、ＩｎＡｓ、あるいは、ＩｎＡｓｘＳｂ１−ｘ、ＩｎｘＧａ１−ｘＳｂ、ＩｎｘＧａ１−ｘＡｓ（０≦ｘ≦１）から成る薄膜とすることが好ましく、更に好ましくは、ＩｎＡｓxＳｂ1-x（０≦ｘ≦１）であり、単結晶ＩｎＳｂ薄膜とすることが特に好ましい。
また、化合物半導体薄膜の膜厚としては、０．１〜４μｍが適当である。磁気抵抗素子の作製プロセスでは、通常のフォトリソグラフィーの技術を用いるが、このとき、ウェットエッチングによって所望の形状に化合物半導体薄膜をメサエッチングすることが多い。このウェットエッチングは膜厚方向のエッチングともに、膜厚方向とは垂直方向のサイドエッチングが進むため、膜厚が厚過ぎると、膜厚方向のエッチングは終了する時点ではサイドエッチングもかなり進むため、素子抵抗値の設計値と実際の素子抵抗値がずれるだけでなく、素子抵抗値の個体差も大きくなる。すなわち、膜厚が４μｍを超えると、フォトリソグラフィーの精度が悪化するため、素子特性が劣化するだけでなく、素子特性にばらつきが大きくなる。また、膜厚が０．１μｍ未満では感磁部１８の体積が小さくなって十分な素子特性が得られないので、化合物半導体薄膜の膜厚としては０．１〜４μｍの範囲とすることが好ましい。 As the compound semiconductor thin film that constitutes the magnetosensitive part 18 of the magnetoresistive element 11, a compound semiconductor composed of elements of group III and group V in the periodic table is generally used. In the present invention, since the compound semiconductor preferably has as high an electron mobility as possible in order to obtain a high magnetoresistance change rate, the compound semiconductor thin film is made of InSb, InAs, or InAs x Sb 1-x. , In x Ga 1-x Sb, In x Ga 1-x As (0 ≦ x ≦ 1) is preferable, and InAs x Sb 1-x (0 ≦ x ≦ 1) is more preferable. And a single crystal InSb thin film is particularly preferable.
Moreover, as a film thickness of a compound semiconductor thin film, 0.1-4 micrometers is suitable. In the process of manufacturing the magnetoresistive element, a normal photolithography technique is used. At this time, the compound semiconductor thin film is often mesa-etched into a desired shape by wet etching. In this wet etching, the side etching in the direction perpendicular to the film thickness direction proceeds with the etching in the film thickness direction. If the film thickness is too thick, the side etching also proceeds considerably when the etching in the film thickness direction is completed. Not only does the design value of the resistance value deviate from the actual element resistance value, but individual differences in element resistance values also increase. That is, when the film thickness exceeds 4 μm, the accuracy of photolithography deteriorates, so that not only the device characteristics deteriorate but also the device characteristics vary greatly. Further, if the film thickness is less than 0.1 μm, the volume of the magnetically sensitive portion 18 becomes small and sufficient element characteristics cannot be obtained. Therefore, the film thickness of the compound semiconductor thin film is preferably in the range of 0.1 to 4 μm. .

化合物半導体薄膜を形成する方法としては、分子線エピタキシー（ＭＢＥ）法を用いることが薄膜の膜厚や組成の制御性が高く特に好ましい方法である。ＭＢＥ法を用いて作製した化合物半導体薄膜から成る感磁部１８を備えた回転検出器においては、歯車１の回転によって生じる磁束密度変化検出のために配置される複数の素子の電子移動度が高いだけでなく、各素子の特性差はほとんどないので、磁界の印加された状態での抵抗値の温度依存性を均一に設定することができる。
また、本例では、感磁部１８である化合物半導体薄膜中にキャリアを増加させ、電子移動度を更に高めるために、ドナー不純物を添加するようにしている。ドナー不純物の添加方法としては、化合物半導体薄膜を形成する際に同時に行ってもよいが、成膜後にイオン注入法を用いて打ち込んでもよい。このとき用いられるドナー不純物としては、化合物半導体が、例えば、ＩｎＳｂやＩｎＡｓのようなIII−Ｖ族化合物半導体の場合には、Ｃ、Ｓｉ、Ｇｅ、ＳｎのようなIV族元素やＳ、Ｓｅ、Ｔｅに代表されるVI族元素を添加するとよい。その中でも特にＳｉ、Ｓｎが好ましい。このように、化合物半導体にドナー不純物をドープし、かつ、上述した均一性の高い不純物ドープ技術を用いて感磁部の電子濃度を適正に制御すれば、感磁部１８の全面に渉り、磁界の印加された状態での抵抗値の温度依存性の均一性を±１．０％以内に設定することができる。 As a method for forming a compound semiconductor thin film, the molecular beam epitaxy (MBE) method is a particularly preferable method because the film thickness and composition of the thin film are highly controllable. In the rotation detector provided with the magnetosensitive part 18 made of the compound semiconductor thin film manufactured by using the MBE method, the electron mobility of a plurality of elements arranged for detecting a change in magnetic flux density caused by the rotation of the gear 1 is high. In addition, since there is almost no characteristic difference between the elements, the temperature dependence of the resistance value in a state where a magnetic field is applied can be set uniformly.
In this example, donor impurities are added to increase the number of carriers in the compound semiconductor thin film that is the magnetically sensitive portion 18 and further increase the electron mobility. The donor impurity may be added simultaneously with the formation of the compound semiconductor thin film, or may be implanted using an ion implantation method after film formation. As a donor impurity used at this time, for example, when the compound semiconductor is a III-V group compound semiconductor such as InSb or InAs, a group IV element such as C, Si, Ge, or Sn, or S, Se, A group VI element typified by Te may be added. Of these, Si and Sn are particularly preferable. Thus, if the compound semiconductor is doped with a donor impurity and the electron concentration of the magnetosensitive portion is appropriately controlled using the above-described highly uniform impurity doping technique, the entire surface of the magnetosensitive portion 18 is affected. The uniformity of the temperature dependence of the resistance value in a state where a magnetic field is applied can be set within ± 1.0%.

また、本発明に用いられる絶縁性基板１７としては、表面が絶縁性もしくは絶縁化された半導体の絶縁層を持つ基板が好ましく、半導体基板の中でもＧａＡｓ、ＩｎＰ、ＧａＰなどの基板を用いると、感磁部１８を構成する化合物半導体薄膜の電子移動度を高くできるので、特に好ましいものとなる。
このとき、絶縁性基板１７の表面粗さを１０オングストローム以内とすることが好ましい。絶縁性基板上には、通常、１０オングストローム程度の酸化膜が形成されており、この酸化膜上で薄膜を成長させると、電子移動度が小さくなってしまうことから、この酸化膜を除去し、表面粗さを１０オングストローム以内とすることにより、化合物半導体薄膜の電子移動度を高めることができる。
また、絶縁性基板１７の表面に高抵抗層または絶縁層を設け、この高抵抗層または絶縁層の上に化合物半導体薄膜を形成することが好ましい。このとき、高抵抗層または絶縁層を化合物半導体薄膜の結晶構造と同一の結晶構造を有する高抵抗層または絶縁層とすれば、薄膜の形状が安定するとともに、結晶境界で相互作用を小さくできるので、結晶構造のミスマッチによる電子移動度の低下を抑制することができる。
特に、化合物半導体薄膜が単結晶ＩｎＳｂ薄膜である場合には、高い電子移動度を実現するため、例えば、ＧａＡｓ、ＡｌｘＧａ１−ｘＡｓ１−ｙＳｂｙ（０≦ｘ≦１，０≦ｙ≦１）などの薄膜の結晶構造と同一の結晶構造を有し、かつ、薄膜との格子定数の差が２．０％以下である絶縁層を設けることが好ましい。 Further, as the insulating substrate 17 used in the present invention, a substrate having a semiconductor insulating layer whose surface is insulative or insulated is preferable. When a substrate such as GaAs, InP, or GaP is used among the semiconductor substrates, the sensitivity is increased. Since the electron mobility of the compound semiconductor thin film which comprises the magnetic part 18 can be made high, it becomes especially preferable.
At this time, the surface roughness of the insulating substrate 17 is preferably within 10 angstroms. On the insulating substrate, an oxide film of about 10 angstroms is usually formed, and when a thin film is grown on this oxide film, the electron mobility decreases, so this oxide film is removed, By setting the surface roughness within 10 angstroms, the electron mobility of the compound semiconductor thin film can be increased.
In addition, it is preferable to provide a high resistance layer or an insulating layer on the surface of the insulating substrate 17 and form a compound semiconductor thin film on the high resistance layer or the insulating layer. At this time, if the high resistance layer or insulating layer is a high resistance layer or insulating layer having the same crystal structure as that of the compound semiconductor thin film, the shape of the thin film can be stabilized and the interaction can be reduced at the crystal boundary In addition, a decrease in electron mobility due to a crystal structure mismatch can be suppressed.
Particularly, when the compound semiconductor thin film is a single crystal InSb thin film, in order to achieve a high electron mobility, for example, GaAs, Al x Ga 1- x As 1-y Sb y (0 ≦ x ≦ 1,0 ≦ It is preferable to provide an insulating layer having the same crystal structure as that of the thin film such as y ≦ 1) and having a lattice constant difference of 2.0% or less from the thin film.

また、端子電極１９及び短絡電極２０に用いられる電極材料は、Ｃｕ単層や、Ｔｉ／Ａｕ，Ｎｉ／Ａｕ，Ｃｒ／Ｃｕ，Ｃｕ／Ｎｉ／Ａｕ，Ｔｉ／Ａｕ／Ｎｉ，Ｃｒ／Ａｕ／Ｎｉ，Ｃｒ／Ｎｉ／Ａｕ／Ｎｉなどのような積層としてもよい。この電極材料は、作製した素子の使用される動作条件と環境条件に耐えられる材質であれば、どのような材料を用いてもかまわない。また、電極を形成する方法としては、電子ビーム蒸着や抵抗加熱蒸着といった一般的な真空蒸着法や、スパッタ法やメッキ法によって形成してもよい。また、電極形成後に端子電極１９及び短絡電極２０と動作層である感磁部１８とのオーミック接触性を良好にするために、急昇温熱アニール（ＲＴＡ）法を用いて熱処理することも好ましい。   The electrode material used for the terminal electrode 19 and the short-circuit electrode 20 is a Cu single layer, Ti / Au, Ni / Au, Cr / Cu, Cu / Ni / Au, Ti / Au / Ni, Cr / Au / Ni. , Cr / Ni / Au / Ni, etc. The electrode material may be any material as long as it can withstand the operating conditions and environmental conditions in which the manufactured element is used. Moreover, as a method for forming the electrode, it may be formed by a general vacuum vapor deposition method such as electron beam vapor deposition or resistance heating vapor deposition, a sputtering method or a plating method. Further, in order to improve the ohmic contact between the terminal electrode 19 and the short-circuit electrode 20 and the magnetically sensitive portion 18 that is the operation layer after the electrodes are formed, it is also preferable to perform heat treatment using a rapid temperature rising thermal annealing (RTA) method.

また、感磁部１８を構成する化合物半導体薄膜を保護する保護膜２１としては、一般的には絶縁性無機質材料であることが好ましく、例えば、窒化シリコン、酸化ケイ素等の薄膜をプラズマＣＶＤ法等により形成したものが好適に用いられる。このとき、保護膜２１の厚さとしては、２００ｎｍ〜５００ｎｍ程度とすることが好ましい。保護膜２１の厚さが２００ｎｍに満たない場合には、空気の遮断が不十分であり信頼性が低下する。また、膜厚が５００ｎｍを超えても保護膜としての効果は特に変わらないので、保護膜２１を特に厚くする必要はなく、５００ｎｍ以下とするのが適当である。
また、軟質樹脂層２２は、硬質樹脂であるモールド樹脂２５による化合物半導体薄膜への圧力や面内応力を緩和する目的で、保護膜２１上に上記部位を覆うように形成されたもので、この軟質樹脂層２２を形成する樹脂は、半導体封止用の樹脂であり、主に、シリコン樹脂やゴム系樹脂が好適に用いられる。また、応力緩和に必要な膜厚としては、シリコン樹脂では、１〜３００μｍが、ゴム系樹脂では１〜１０μｍが適当である。
シリコン樹脂による軟質樹脂層２２を形成する方法としては、例えば、ディスペンサでシリコン樹脂の液滴を感磁部１８に滴下し、これを熱硬化（２００℃、２時間程度）させて、約３００μｍ程度の柔らかいコンタクト樹脂層を形成したり、感光性のシリコン樹脂をスピンコートでウエーハ上に塗布し、フォトマスクを用いてパターンニングして、感磁部１８のみを覆うようにし、現像後、熱硬化させて数１０μｍ程度のコンタクト樹脂層を形成する方法などがある。なお、感光性のシリコン樹脂としては、ネガタイプのものであっても良いし、ポジタイプのものであっても良い。
また、ゴム系樹脂の場合には、肉厚を数μｍ程度とするためには、感光性のものを用いてパターンニングして、感磁部１８のみを覆うようにすることが好ましいが、他の方法であっても良い。
なお、軟質樹脂層２２は、上記モールド樹脂に対する化合物半導体薄膜への応力緩和効果だけでなく、万が一、回転検出器１０が歯車１に接触して衝撃を受けた場合にも、その衝撃を緩和し、化合物半導体薄膜を保護することができるという利点を有する。 In addition, the protective film 21 that protects the compound semiconductor thin film that constitutes the magnetosensitive portion 18 is generally preferably an insulating inorganic material. For example, a thin film of silicon nitride, silicon oxide, or the like is formed by a plasma CVD method or the like. Those formed by the above are preferably used. At this time, the thickness of the protective film 21 is preferably about 200 nm to 500 nm. When the thickness of the protective film 21 is less than 200 nm, air is not sufficiently blocked and the reliability is lowered. Further, even if the film thickness exceeds 500 nm, the effect as a protective film is not particularly changed. Therefore, the protective film 21 does not need to be particularly thick, and is suitably 500 nm or less.
The soft resin layer 22 is formed on the protective film 21 so as to cover the above-mentioned part for the purpose of relaxing the pressure and in-plane stress on the compound semiconductor thin film by the mold resin 25 which is a hard resin. The resin forming the soft resin layer 22 is a resin for semiconductor encapsulation, and mainly a silicon resin or a rubber-based resin is preferably used. Moreover, as a film thickness required for stress relaxation, 1 to 300 μm is appropriate for silicon resin, and 1 to 10 μm is appropriate for rubber-based resin.
As a method of forming the soft resin layer 22 made of silicon resin, for example, a dispenser of silicon resin is dropped on the magnetic sensitive part 18 with a dispenser, and this is thermally cured (200 ° C., about 2 hours) to be about 300 μm. A soft contact resin layer, or a photosensitive silicon resin is applied onto the wafer by spin coating, and patterned using a photomask so as to cover only the magnetically sensitive portion 18, and after development, thermosetting And a method of forming a contact resin layer of about several tens of μm. The photosensitive silicone resin may be a negative type or a positive type.
In the case of a rubber-based resin, it is preferable to perform patterning using a photosensitive material so as to cover only the magnetosensitive portion 18 in order to make the thickness about several μm. This method may be used.
The soft resin layer 22 reduces not only the stress relaxation effect on the compound semiconductor thin film with respect to the mold resin, but also the shock when the rotation detector 10 contacts the gear 1 and receives an impact. The compound semiconductor thin film can be protected.

次に、磁気抵抗素子１１の作製方法について説明する。
図６（ａ）〜（ｅ）は、３端子の磁気抵抗素子１１の作製プロセスフローを示す図で、プロセスとしては、通常のフォトリソグラフィーの技術を用いることができる。
はじめに、図６（ａ）に示すように、絶縁性基板であるＧａＡｓ基板１７上に、感磁部１８を構成するためのＩｎＳｂ薄膜１８Ｆを形成する。具体的には、分子線エピタキシー（ＭＢＥ）法を用いて、半絶縁性のＧａＡｓ単結晶基板１７の（１００）面上に、化合物半導体薄膜としてＳｎドープＩｎＳｂ薄膜１８Ｆをエピタキシャル成長させる。
次に、図６（ｂ）に示すように、ＩｎＳｂのメサエッチング用のフォトマスクを用いて、感磁部のパターンを露光・現像した後に、ＩｎＳｂ薄膜１８Ｆを塩酸・過酸化水素系のエッチング液で所望の形状にメサエッチングして、第１及び第２の磁気抵抗素子１８ａ，１８ｂを形成する。なお、感磁部である第１及び第２の磁気抵抗素子１８ａ，１８ｂの間隔は、検出する歯車１の山と谷の間隔（歯車のピッチをＰとすると、Ｐ／２）に合わせるものとする。
その後、図６（ｃ）に示すように、磁気抵抗素子１８ａ，１８ｂ上に、複数の短絡電極２０を形成し、更に、図６（ｄ）に示すように、窒化シリコン薄膜から成る保護膜２１を、プラズマＣＶＤ法により形成する。そして、図６（ｅ）に示すように、端子電極１９部分のみの窒化シリコン膜を反応性イオンエッチング装置を用いて除去した後、端子電極１９（入力端子１９ａ，１９ｂ及び出力端子１９ｃ）を形成する。最後に、磁気抵抗素子の感磁部面上（実際には、保護膜２１上）に、上記部位を覆うように、柔らかいシリコン樹脂層から成る軟質樹脂層２２を形成する。
このようにして、ＳｎドープＩｎＳｂ薄膜１８Ｆを感磁部１８とし、端子電極１９を３個を有し、各端子電極１９間に複数の短絡電極２０を有する高磁界感度の３端子構成の磁気抵抗素子から成る磁気抵抗素子１１を、フォトリソグラフィーを応用した微細加工プロセスの応用により、１枚のウエーハ上に多数製作することができる。
次に、ウエーハから、ダイシングにより、個別の３端子の磁気抵抗素子１１に切離す。こうして製作した磁気抵抗素子１１のチップを、リードフレームを利用して、エポキシ樹脂などの硬質樹脂によりパッケージし、永久磁石１２が保持された磁石ホルダー１５とともに樹脂ケース１６に収納することにより、図１に示すような、本発明の回転検出器１０を製作することができる。 Next, a method for manufacturing the magnetoresistive element 11 will be described.
FIGS. 6A to 6E are diagrams showing a process flow for producing the three-terminal magnetoresistive element 11, and a normal photolithography technique can be used as the process.
First, as shown in FIG. 6A, an InSb thin film 18F for forming the magnetic sensitive part 18 is formed on a GaAs substrate 17 which is an insulating substrate. Specifically, a Sn-doped InSb thin film 18F is epitaxially grown as a compound semiconductor thin film on the (100) plane of the semi-insulating GaAs single crystal substrate 17 by using molecular beam epitaxy (MBE).
Next, as shown in FIG. 6B, using a photomask for mesa etching of InSb, after exposing and developing the pattern of the magnetically sensitive portion, the InSb thin film 18F is etched with a hydrochloric acid / hydrogen peroxide etching solution. Then, the first and second magnetoresistive elements 18a and 18b are formed by mesa etching into a desired shape. The distance between the first and second magnetoresistive elements 18a and 18b, which are the magnetic sensing parts, is adjusted to the distance between the peaks and valleys of the gear 1 to be detected (P / 2 when the gear pitch is P). To do.
Thereafter, as shown in FIG. 6C, a plurality of short-circuit electrodes 20 are formed on the magnetoresistive elements 18a and 18b. Further, as shown in FIG. 6D, a protective film 21 made of a silicon nitride thin film is formed. Is formed by plasma CVD. Then, as shown in FIG. 6E, after the silicon nitride film of only the terminal electrode 19 portion is removed using a reactive ion etching apparatus, the terminal electrodes 19 (input terminals 19a and 19b and output terminal 19c) are formed. To do. Finally, a soft resin layer 22 made of a soft silicon resin layer is formed on the surface of the magnetosensitive element of the magnetoresistive element (actually on the protective film 21) so as to cover the portion.
In this way, the magnetic resistance of a three-terminal configuration with high magnetic field sensitivity, in which the Sn-doped InSb thin film 18F is used as the magnetic sensing portion 18, the terminal electrodes 19 are provided, and the plurality of short-circuit electrodes 20 are provided between the terminal electrodes 19. A large number of magnetoresistive elements 11 composed of elements can be manufactured on a single wafer by applying a microfabrication process using photolithography.
Next, the wafer is separated into individual three-terminal magnetoresistive elements 11 by dicing. The chip of the magnetoresistive element 11 manufactured in this way is packaged with a hard resin such as an epoxy resin using a lead frame, and is housed in a resin case 16 together with a magnet holder 15 holding a permanent magnet 12. A rotation detector 10 of the present invention as shown in FIG.

本例では、３端子の磁気抵抗素子１１を、その磁気抵抗変化率が５０％となる磁束密度となるように、永久磁石１２によるバイアス磁界の大きさを設定している。また、本例においては、前記磁気抵抗素子１１の抵抗値の温度依存性の均一性は、感磁部１８の全面に渉り、磁界の印加された状態において±１．０％以内である。
図３（ａ），（ｂ）に示した３端子の磁気抵抗素子１１の抵抗値の磁場依存性を測定するため、磁気抵抗素子１１に電磁石で一様な磁場をかけ、端子電極１９ａと端子電極１９ｃとの間の抵抗値を測定した結果を図７に示す。また、図８は、磁気抵抗変化率ΔＲ／Ｒ０と磁束密度の関係を示す図で、ここで、ΔＲ＝ＲＢ−Ｒ０であり、ＲＢは磁場中での抵抗値、Ｒ０は磁場なしでの抵抗値である。なお、メサエッチング後の化合物半導体薄膜の幅（電流に直交する方向の幅：素子幅）をＷとし、短絡電極間の距離（素子長）をＬとしたとき、Ｌ／Ｗを形状因子と呼ぶが、本実施の形態１では、形状因子を、Ｌ／Ｗ＝０．２とした。
図８からわかるように、磁束密度が大きくなるほど、磁気抵抗変化率ΔＲ／Ｒ０の傾きは大きくなる。すなわち、磁界に対する感度が大きくなる。この磁気抵抗変化率ΔＲ／Ｒ０は、電子移動度をμ、磁束密度をＢとすると、これらの積μＢに相当するもので、この曲線は、低磁界領域ではほぼ二次曲線的に増加し、高磁界領域ではほぼ直線的に変化する。すなわち、電子移動度μが高い磁気抵抗素子ほど磁束密度が小さい領域から直線的に変化する。
磁気抵抗素子の感度を良くするためには、この直線領域を使用することが好ましく、特に、磁気抵抗変化率ΔＲ／Ｒ０が５０％増加する磁束密度以上で使用することが好ましい。
ちなみに、フェライト磁石の表面磁束密度は０．１〜０．１５Ｔ程度であり、ＳｍＣｏ磁石の表面磁束密度は０．２５〜０．３Ｔ程度であるので、磁気抵抗素子の感度を良くするためには、ＳｍＣｏ磁石等の希土類合金系の永久磁石を用いることが好ましい。 In this example, the magnitude of the bias magnetic field by the permanent magnet 12 is set so that the magnetoresistive element 11 having three terminals has a magnetic flux density at which the magnetoresistance change rate is 50%. In this example, the uniformity of the temperature dependence of the resistance value of the magnetoresistive element 11 extends over the entire surface of the magnetic sensing portion 18 and is within ± 1.0% when a magnetic field is applied.
In order to measure the magnetic field dependence of the resistance value of the three-terminal magnetoresistive element 11 shown in FIGS. 3A and 3B, a uniform magnetic field is applied to the magnetoresistive element 11 with an electromagnet, and the terminal electrode 19a and the terminal The result of measuring the resistance value between the electrode 19c is shown in FIG. Further, FIG. 8 is a diagram showing the relationship between the magnetoresistance ratio [Delta] R / R 0 and the magnetic flux density, wherein a ΔR = R B -R 0, R B is the resistance in a magnetic field, R 0 is Resistance value without magnetic field. When the width of the compound semiconductor thin film after mesa etching (width in the direction orthogonal to the current: element width) is W and the distance between the short-circuit electrodes (element length) is L, L / W is called a shape factor. However, in the first embodiment, the shape factor is L / W = 0.2.
As can be seen from FIG. 8, as the magnetic flux density increases, the slope of the magnetoresistance change rate ΔR / R 0 increases. That is, the sensitivity to the magnetic field is increased. The magnetoresistance ratio [Delta] R / R 0, when the electron mobility mu, the magnetic flux density is B, which corresponds to the product thereof .mu.B, this curve in the low magnetic field region increases substantially quadratically In the high magnetic field region, it changes almost linearly. That is, the magnetoresistive element having a higher electron mobility μ changes linearly from the region where the magnetic flux density is small.
In order to improve the sensitivity of the magnetoresistive element, it is preferable to use this linear region, and it is particularly preferable to use it at a magnetic flux density at which the magnetoresistance change rate ΔR / R 0 increases by 50% or more.
Incidentally, since the surface magnetic flux density of the ferrite magnet is about 0.1 to 0.15T and the surface magnetic flux density of the SmCo magnet is about 0.25 to 0.3T, in order to improve the sensitivity of the magnetoresistive element. Rare earth alloy permanent magnets such as SmCo magnets are preferably used.

本発明の磁気検出部となる３端子の磁気抵抗素子１１では、図９に示すように、第１及び第２の磁気抵抗素子１８ａ，１８ｂは、歯車１の山と谷とにそれぞれ合わせて配置されており、磁気抵抗素子１１の入力端子である端子電極１９ａ，１９ｂ間に直流電源４を接続することにより、第１及び第２の磁気抵抗素子１８ａ，１８ｂの中点である端子電極１９ｃからは、歯車１の回転に伴って、図１０に示すような、Ａ相またはＢ相の非差動出力（Ｖｏｕｔ）が出力される。
本例の磁気抵抗素子１１は、前記のように、１つのチップ上に第１及び第２の磁気抵抗素子１８ａ，１８ｂを同時に形成しているので、磁気抵抗素子１８ａと磁気抵抗素子１８ｂとの間隔は歯車の山と谷の間隔（Ｐ／２）に等しくなるように作製することができる。すなわち、磁気抵抗素子１８ａ，１８ｂの間隔が歯車１の山谷ピッチと正確に合っているため、個体差はほとんど生じないだけでなく、感磁部１８は、半絶縁性のＧａＡｓ単結晶から成る絶縁性基板１７上に、ＳｎドープＩｎＳｂ薄膜１８Ｆを分子線エピタキシー法により成長させて成る高い電子移動度を有する化合物半導体から構成されているので、第１及び第２の磁気抵抗素子１８ａ，１８ｂの素子特性も揃っており、かつ、抵抗値の温度依存性の均一性を±１．０％以内にすることができる。したがって、３端子の磁気抵抗素子１１を用いることで、検出感度の高くかつ温度ドリフトの極めて小さな回転検出器１０を製作することができる。 In the three-terminal magnetoresistive element 11 serving as the magnetic detecting portion of the present invention, as shown in FIG. 9, the first and second magnetoresistive elements 18a and 18b are arranged in accordance with the crest and trough of the gear 1, respectively. The DC power supply 4 is connected between the terminal electrodes 19a and 19b that are input terminals of the magnetoresistive element 11, so that the terminal electrode 19c that is the midpoint of the first and second magnetoresistive elements 18a and 18b is connected. As the gear 1 rotates, an A-phase or B-phase non-differential output (V out ) is output as shown in FIG.
In the magnetoresistive element 11 of this example, since the first and second magnetoresistive elements 18a and 18b are simultaneously formed on one chip as described above, the magnetoresistive element 18a and the magnetoresistive element 18b The distance can be made to be equal to the distance (P / 2) between the crest and trough of the gear. That is, since the interval between the magnetoresistive elements 18a and 18b is exactly matched with the peak-and-valley pitch of the gear 1, there is almost no individual difference, and the magnetosensitive portion 18 is an insulating material made of a semi-insulating GaAs single crystal. The first and second magnetoresistive elements 18a and 18b are composed of a compound semiconductor having a high electron mobility obtained by growing a Sn-doped InSb thin film 18F on a conductive substrate 17 by molecular beam epitaxy. The characteristics are uniform and the uniformity of the temperature dependence of the resistance value can be within ± 1.0%. Therefore, by using the three-terminal magnetoresistive element 11, the rotation detector 10 having high detection sensitivity and extremely small temperature drift can be manufactured.

このように、本実施の形態１によれば、絶縁性基板であるＧａＡｓ基板１７上に、ドナー不純物としてＳｎをドープした、高い電子移動度を有するＩｎＳｂ薄膜を、分子線エピタキシー（ＭＢＥ）法を用いてエピタキシャル成長させて、これを感磁部１８とした３端子の磁気抵抗素子１１を形成するとともに、感磁部１８の上部側を、例えば、シリコン樹脂、または、ゴム系樹脂から成る軟質樹脂層２２で覆った後、モールド樹脂２５によりモールドしたので、磁気抵抗素子１８ａ，１８ｂの抵抗値のばらつきや温度依存性を小さくすることができるとともに、モールドでの応力を緩和することができるので、検出感度を向上させることができる。
また、３端子の磁気抵抗素子１１を用いて回転検出器１０を作製したので、歯車１の回転の検出精度を高めることができるとともに温度ドリフトを大幅に低減することができる。 Thus, according to the first embodiment, an InSb thin film having high electron mobility doped with Sn as a donor impurity on a GaAs substrate 17 which is an insulating substrate is subjected to molecular beam epitaxy (MBE). The three-terminal magnetoresistive element 11 is formed by epitaxial growth using this as a magnetosensitive part 18, and the upper side of the magnetosensitive part 18 is a soft resin layer made of, for example, a silicon resin or a rubber-based resin. After being covered with 22 and molded with the mold resin 25, it is possible to reduce variations in resistance values and temperature dependence of the magnetoresistive elements 18a and 18b, and to relieve stress in the mold. Sensitivity can be improved.
In addition, since the rotation detector 10 is manufactured using the three-terminal magnetoresistive element 11, the detection accuracy of the rotation of the gear 1 can be increased and the temperature drift can be greatly reduced.

なお、実施の形態１では、歯車１の回転を検出する回転検出器１０について説明したが、本発明はこれに限るものではなく、例えば、円柱棒の表面に凹部又は凸部を付けた回転体など、他の回転体の回転を検出する一般の回転検出器にも適用可能である。
更には、図１１に示すような、凹凸のある磁性体から成る移動体５０の前記凹凸の検出にも適用可能である。
また、磁気抵抗素子１１に代えて、図１２に示すような、軟磁性体であるフェライト基板から成る磁気誘導層２６を備えた磁気抵抗素子１１Ｔを用いて回転検出器１０を作製すれば、出力信号振幅の大きな回転検出器を得ることができる。
磁気誘導層２６は、永久磁石１２からの磁界を感磁部１８に集磁する機能を有するので、この集磁効果により、磁気抵抗素子１８ａ，１８ｂに作用する磁界の大きさを更に大きくすることができるだけでなく、磁気抵抗素子１８ａ，１８ｂの端部においても、磁界の垂直成分が増加するため、出力振幅が増加し、検出感度が向上する。
磁気誘導層２６は、例えば、図１３に示すように、微細加工プロセスの応用により１枚のウエーハ１７Ｐ上に素子を多数製作した後、裏面研磨によって絶縁性基板１７となるウエーハ１７Ｐを所定の厚さだけ研磨し、この裏面に、接着剤により、厚さ０．２５ｍｍ程度のフェライト基板２６Ｐに貼りあわせ、その後、ダイシングにより個別の磁気抵抗素子１１Ｔに切離すことにより作製する。なお、前記切り離しは、通常、上述した軟質樹脂層２２の形成後に行う。 In the first embodiment, the rotation detector 10 for detecting the rotation of the gear 1 has been described. However, the present invention is not limited to this, and for example, a rotating body with a concave or convex portion on the surface of a cylindrical rod. The present invention is also applicable to a general rotation detector that detects the rotation of other rotating bodies.
Furthermore, the present invention can also be applied to detection of the unevenness of the moving body 50 made of a magnetic material having unevenness as shown in FIG.
If the rotation detector 10 is manufactured using a magnetoresistive element 11T having a magnetic induction layer 26 made of a soft magnetic ferrite substrate as shown in FIG. A rotation detector having a large signal amplitude can be obtained.
Since the magnetic induction layer 26 has a function of collecting the magnetic field from the permanent magnet 12 in the magnetic sensing part 18, the magnitude of the magnetic field acting on the magnetoresistive elements 18a and 18b can be further increased by this magnetic collection effect. In addition, since the vertical component of the magnetic field increases at the ends of the magnetoresistive elements 18a and 18b, the output amplitude increases and the detection sensitivity improves.
For example, as shown in FIG. 13, the magnetic induction layer 26 is manufactured by manufacturing a large number of elements on a single wafer 17P by applying a microfabrication process, and then polishing the wafer 17P to be the insulating substrate 17 by a back surface polishing to a predetermined thickness. This is polished and bonded to the back surface of the ferrite substrate 26P having a thickness of about 0.25 mm by an adhesive, and then separated into individual magnetoresistive elements 11T by dicing. The separation is usually performed after the formation of the soft resin layer 22 described above.

また、前記例では、３端子の磁気抵抗素子１１を１個として、Ａ相またはＢ相の非差動出力を出力するようにしたが、図１４に示すように、歯車として、１歯が欠歯している歯車１Ｋを用いるとともに、１チップ上に磁気抵抗素子１１と同一構成の磁気抵抗素子を２個備え、一方の磁気抵抗素子１１ＡをＡ相またはＢ相用とし、他方の磁気抵抗素子１１Ｋを、インデックス検出用であるＺ相用とした回転検出器１０Ｋを作製することができる。これにより、図１５（ａ），（ｂ）に示すような、Ａ相またはＢ相の非差動出力とともに、欠歯を検出するＺ相での出力信号を得ることができるので、回転検出器１０Ｋからの出力信号を磁気エンコーダとして使用することができる。高分解能の磁気エンコーダを得るためには、回転検出器からの信号が、温度に対して安定していることが極めて重要であることから、感度も高く、温度ドリフトも小さい本発明の回転検出器１０Ｋを用いることにより、高分解能の磁気エンコーダを実現することが可能となる。   In the above example, the three-terminal magnetoresistive element 11 is used as one to output an A-phase or B-phase non-differential output. However, as shown in FIG. The toothed gear 1K is used, two magnetoresistive elements having the same configuration as the magnetoresistive element 11 are provided on one chip, one magnetoresistive element 11A is used for A phase or B phase, and the other magnetoresistive element A rotation detector 10K in which 11K is used for the Z phase for index detection can be manufactured. Thus, as shown in FIGS. 15 (a) and 15 (b), an A-phase or B-phase non-differential output and an output signal in the Z phase for detecting missing teeth can be obtained. The output signal from 10K can be used as a magnetic encoder. In order to obtain a high-resolution magnetic encoder, it is extremely important that the signal from the rotation detector is stable with respect to temperature. Therefore, the rotation detector of the present invention has high sensitivity and small temperature drift. By using 10K, a high-resolution magnetic encoder can be realized.

［実施の形態２］
実施の形態１では、３端子構成の磁気抵抗素子１１について説明したが、本発明はこれに限るものではなく、４端子の磁気抵抗素子など、他の構成の磁気抵抗素子にも適用可能である。
図１６は、本発明の実施の形態２に係る４端子の磁気抵抗素子１１Ｍの構成を示す図で、この磁気抵抗素子１１Ｍは、実施の形態１と同様にして作製される。同図は、ダイシングにより個別の磁気抵抗素子１１Ｍに切離した状態のものを示したもので、この磁気抵抗素子１１Ｍは、１つのチップ上に４個の磁気抵抗素子１８Ａ〜１８Ｄが作製されており、図１７に示すように、磁気抵抗素子１８Ａと磁気抵抗素子１８Ｂの間隔と磁気抵抗素子１８Ｃと磁気抵抗素子１８Ｄの間隔は、ともに、歯車のピッチをＰとすると、歯車の山と谷の間隔であるＰ／２に等しく、かつ、磁気抵抗素子１８Ａ、磁気抵抗素子１８Ｃ、及び、磁気抵抗素子１８Ｂと磁気抵抗素子１８Ｄとは、歯車１の回転方向に対して、Ｐ／４だけずらして形成されている。これにより、端子電極１９Ａと端子電極１９Ｂとの間に直流電源４を接続すれば、歯車１の回転に伴って、磁気抵抗素子１８Ａと磁気抵抗素子１８Ｂとの中点に設けられた端子電極１９ＭからはＡ相の信号が、磁気抵抗素子１８Ｃと磁気抵抗素子１８Ｄとの中点に設けられた端子電極１９Ｎからは、Ａ相とは９０°の位相差を有するＢ相の信号が出力され、Ａ相／Ｂ相の非差動２出力を出力する４端子の磁気抵抗素子１１Ｍを作製することができる。
また、この磁気抵抗素子１１Ｍを用いることにより、歯車１の回転に伴ってＡ相／Ｂ相の非差動２出力を出力する回転検出器を作製することができる。 [Embodiment 2]
In the first embodiment, the three-terminal configuration magnetoresistive element 11 has been described. However, the present invention is not limited to this, and the present invention can be applied to other configurations of magnetoresistive elements such as a four-terminal magnetoresistive element. .
FIG. 16 is a diagram showing a configuration of a 4-terminal magnetoresistive element 11M according to Embodiment 2 of the present invention, and this magnetoresistive element 11M is manufactured in the same manner as in Embodiment 1. This figure shows a state in which the individual magnetoresistive elements 11M are separated by dicing. In the magnetoresistive element 11M, four magnetoresistive elements 18A to 18D are formed on one chip. 17, the distance between the magnetoresistive element 18A and the magnetoresistive element 18B and the distance between the magnetoresistive element 18C and the magnetoresistive element 18D are as follows. Is equal to P / 2, and the magnetoresistive element 18A, the magnetoresistive element 18C, and the magnetoresistive element 18B and the magnetoresistive element 18D are formed so as to be shifted by P / 4 with respect to the rotation direction of the gear 1. Has been. Thus, if the DC power supply 4 is connected between the terminal electrode 19A and the terminal electrode 19B, the terminal electrode 19M provided at the midpoint between the magnetoresistive element 18A and the magnetoresistive element 18B as the gear 1 rotates. The A phase signal is output from the terminal electrode 19N provided at the midpoint between the magnetoresistive element 18C and the magnetoresistive element 18D, and the B phase signal having a phase difference of 90 ° from the A phase is output from A four-terminal magnetoresistive element 11M that outputs two non-differential outputs of A phase / B phase can be manufactured.
Further, by using this magnetoresistive element 11M, a rotation detector that outputs two non-differential outputs of A phase / B phase as the gear 1 rotates can be manufactured.

従来の回転検出器の中には、４個の磁気抵抗素子を個別に切離し、ダイボンディグで配置しているものが多かったが、これでは各素子の間隔と歯車の山谷ピッチとが微妙に異なるため、出力信号振幅、Ａ相／Ｂ相の位相差にかなり個体差が生じていた。
これに対して、本実施の形態２の磁気抵抗素子１１Ｍは、１つのチップ上に４個の磁気抵抗素子１８Ａ〜１８Ｄを同時に形成したので、磁気抵抗素子１１Ａと磁気抵抗素子１１Ｂの間隔および磁気抵抗素子１１Ｃと磁気抵抗素子１１Ｄの間隔は歯車の山と谷の間隔（Ｐ／２）に等しくなるように正確に作製することができる。したがって、各素子の間隔と歯車１の山谷ピッチとがと正確に合っているため、構造状の個体差はほとんど生じない。
また、磁気抵抗素子１８Ａ〜１８Ｄは、実施の形態１と同様に、ＧａＡｓ基板１７上に、分子線エピタキシー法を用いて形成された、ＳｎドープＩｎＳｂ薄膜から構成されているので、４個の磁気抵抗素子１８Ａ〜１８Ｄの素子特性も揃っており、かつ、抵抗値の温度依存性の均一性を±１．０％以内にすることができるので、検出感度が高く、かつ、温度ドリフトの極めて小さな回転検出器を製作することができる。 In many conventional rotation detectors, four magnetoresistive elements are separated individually and arranged by die bonding, but this is because the distance between each element and the pitch of the gears are slightly different. There were considerable individual differences in the output signal amplitude and the phase difference between the A phase and the B phase.
On the other hand, in the magnetoresistive element 11M of the second embodiment, since the four magnetoresistive elements 18A to 18D are simultaneously formed on one chip, the distance between the magnetoresistive element 11A and the magnetoresistive element 11B and the magnetic The distance between the resistance element 11C and the magnetoresistance element 11D can be accurately manufactured so as to be equal to the distance (P / 2) between the crests and troughs of the gear. Therefore, since the interval between the elements and the pitch of the peaks and valleys of the gear 1 are accurately matched, there is almost no difference in individual structural features.
Further, since the magnetoresistive elements 18A to 18D are composed of Sn-doped InSb thin film formed on the GaAs substrate 17 by using the molecular beam epitaxy as in the first embodiment, the four magnetic elements The element characteristics of the resistance elements 18A to 18D are uniform, and the uniformity of the temperature dependence of the resistance value can be within ± 1.0%, so that the detection sensitivity is high and the temperature drift is extremely small. A rotation detector can be manufactured.

また、図１８に示すように、歯車として、１歯が欠歯している歯車１Ｋを用いるとともに、１チップ上に４端子の磁気抵抗素子１１と同様の構成の磁気抵抗素子を２個備え、一方の磁気抵抗素子１１ＳをＡ相／Ｂ相用とし、他方の磁気抵抗素子１１ＺをＺａ／Ｚｂ相用とした回転検出器１０Ｚを作製すれば、図１９（ａ），（ｂ）に示すような、Ａ相／Ｂ相の非差動出力とともに、欠歯を検出するＺａ／Ｚｂ相での出力信号を得ることができるので、回転検出器１０Ｚからの出力信号を高精度／高分解能の磁気エンコーダとして使用することが可能となる。なお、図１９では、図を見やすくするため、Ｚａ相の出力信号のみを示した。   Further, as shown in FIG. 18, a gear 1K with one missing tooth is used as a gear, and two magnetoresistive elements having the same configuration as the four-terminal magnetoresistive element 11 are provided on one chip. If a rotation detector 10Z in which one magnetoresistive element 11S is for A phase / B phase and the other magnetoresistive element 11Z is for Za / Zb phase is manufactured, as shown in FIGS. 19 (a) and 19 (b). In addition, since the output signal in the Za / Zb phase for detecting missing teeth can be obtained together with the non-differential output of the A phase / B phase, the output signal from the rotation detector 10Z can be used as a high-precision / high-resolution magnetic signal. It can be used as an encoder. In FIG. 19, only the output signal of the Za phase is shown to make the drawing easier to see.

また、実施の形態２では、Ａ相／Ｂ相の非差動２出力を出力する４端子の磁気抵抗素子１１Ｍについて説明したが、図２０に示すように、４個の磁気抵抗素子１１ａ〜１１ｄがフルブリッジ構造に接続された４端子磁気抵抗素子から構成され、かつ、互いに隣接して接続されていない２対の磁気抵抗素子（磁気抵抗素子１１ａと磁気抵抗素子１１ｄ、及び、磁気抵抗素子１１ｂと磁気抵抗素子１１ｃ）がそれぞれ同相の磁界変化を受けるように、各磁気抵抗素子１１ａ〜１１ｄを配置した構成の磁気抵抗素子１１Ｐを作製することもできる。この磁気抵抗素子１１Ｐでは、図２１に示すように、磁気抵抗素子１１ａと磁気抵抗素子１１ｂとの中点の端子電極１９ｍからはＡ相の、磁気抵抗素子１１ｃと磁気抵抗素子１１ｄとの中点の端子電極１９ｎからは、Ａ相とは１８０°の位相差を有するＡ−相信号が出力されるので、Ａ相／Ａ−相、あるいは、Ｂ相／Ｂ−相の差動単相出力を出力する４端子の磁気抵抗素子１１Ｐと、これを用いた回転検出器を作製することができる。   In the second embodiment, the four-terminal magnetoresistive element 11M that outputs two non-differential outputs of A phase / B phase has been described. However, as shown in FIG. 20, four magnetoresistive elements 11a to 11d are provided. Is composed of a four-terminal magnetoresistive element connected in a full-bridge structure, and two pairs of magnetoresistive elements (the magnetoresistive element 11a, the magnetoresistive element 11d, and the magnetoresistive element 11b) that are not connected adjacent to each other. And the magnetoresistive element 11c) can also be manufactured to have a configuration in which the magnetoresistive elements 11a to 11d are arranged so that each of the magnetoresistive elements 11c) receives a change in the magnetic field in phase. In the magnetoresistive element 11P, as shown in FIG. 21, the midpoint between the magnetoresistive element 11c and the magnetoresistive element 11d of the A phase from the midpoint terminal electrode 19m of the magnetoresistive element 11a and the magnetoresistive element 11b. Since the A-phase signal having a phase difference of 180 ° with respect to the A phase is output from the terminal electrode 19n, the differential single phase output of the A phase / A-phase or the B phase / B-phase is output. A 4-terminal magnetoresistive element 11P to output and a rotation detector using the same can be manufactured.

また、４端子の磁気抵抗素子１１Ｐを２組配置し、それぞれの中点の端子電極から、Ａ相／Ａ−相、及び、Ｂ相／Ｂ−相の差動２相出力を得るようにすることも可能である。あるいは、４端子の差動の磁気抵抗素子１１Ｐを３個備え、それぞれ、Ａ相／Ａ−相、Ｂ相／Ｂ−相、Ｚ相／Ｚ−相としてもよい。
更に、歯車として、１歯が欠歯している歯車１Ｋを用いるとともに、８個の磁気抵抗素子を有する差動の素子（１１Ｐ×２）を１個と、差動の４端子の磁気抵抗素子を１個備えた磁気抵抗素子も作製し、それぞれ、Ａ相／Ａ−相、Ｂ相／Ｂ−相、Ｚ相／Ｚ−相とするようにしてもよい。
これらの磁気抵抗素子はいずれも１チップ上に作製することができるので、実施の形態１，２と同様に、各素子の抵抗値も揃っており、かつ、抵抗値の温度依存性を±１．０％以内と均一にすることができるので、いずれの構成の磁気抵抗素子を用いた場合にも、検出感度が高く、かつ、温度ドリフトの極めて小さな回転検出器を製作することができる。 Further, two sets of four-terminal magnetoresistive elements 11P are arranged so that differential two-phase outputs of A phase / A-phase and B phase / B-phase can be obtained from the respective terminal electrodes at the midpoint. It is also possible. Alternatively, three differential magnetoresistive elements 11P having four terminals may be provided, which may be A phase / A-phase, B phase / B-phase, and Z phase / Z-phase, respectively.
Further, a gear 1K with one tooth missing is used as a gear, and one differential element (11P × 2) having eight magnetoresistive elements and a differential four-terminal magnetoresistive element Alternatively, a magnetoresistive element including one of these may be manufactured, and the phase may be A phase / A-phase, B phase / B-phase, and Z phase / Z-phase, respectively.
Since all of these magnetoresistive elements can be fabricated on one chip, the resistance values of the respective elements are uniform and the temperature dependence of the resistance value is ± 1 as in the first and second embodiments. Since it can be made uniform within 0.0%, a rotation detector having high detection sensitivity and extremely small temperature drift can be manufactured regardless of which magnetoresistive element is used.

［実施の形態３］
実施の形態１，２では、永久磁石１２を磁石ホルダー１５に収納した構成の回転検出器１０，１０Ｋなどについて説明したが、図２２に示すように、エポキシ樹脂などのモールド樹脂２５の磁気抵抗素子１１が配置されている側とは反対側に、永久磁石１２を接着剤等により固定するようにすれば、磁気抵抗素子１１（または、磁気抵抗素子１１Ｍ，１１Ｐなど）と永久磁石１２とがモールド樹脂２５により一体化された構成の回転検出器１０Ｈを構成することができる。図２３に示すように、磁気抵抗素子１１の中心と永久磁石１２の中心とを一致させれば、磁気抵抗素子１８ａ，１８ｂに作用する磁界の分布を同じにできるので、温度ドリフトを更に小さくすることができる。
この回転検出器１０Ｈも、図２４（ａ），（ｂ）に示すように、回転検出器１０と同様に、円筒状の樹脂ケース１６に収納される。このとき、リードフレーム２４Ｌを感磁部面に対して垂直方向に折り曲げるようにすれば、リードフレーム２４Ｌは樹脂ケース１６に接触することはないので、樹脂ケース１６に代えて、金属ケースを使用した場合でも、信号線の接触の問題が起こることはない。
なお、回転検出器１０Ｈは、図２５に示すように、プリント基板２７等に直接接続して使用する場合にも最適な構造である。
また、４端子の磁気抵抗素子１１Ｍを回転検出器１０Ｈに用いる場合には、図２６に示すように、リードフレーム２４Ｌを両側から出す構造としてもよい。 [Embodiment 3]
In the first and second embodiments, the rotation detectors 10 and 10K having the configuration in which the permanent magnet 12 is housed in the magnet holder 15 have been described. As shown in FIG. 22, the magnetoresistive element of the mold resin 25 such as an epoxy resin is used. If the permanent magnet 12 is fixed with an adhesive or the like on the side opposite to the side on which the magnet 11 is disposed, the magnetoresistive element 11 (or the magnetoresistive elements 11M, 11P, etc.) and the permanent magnet 12 are molded. The rotation detector 10H having a configuration integrated with the resin 25 can be configured. As shown in FIG. 23, by making the center of the magnetoresistive element 11 coincide with the center of the permanent magnet 12, the distribution of the magnetic field acting on the magnetoresistive elements 18a and 18b can be made the same, so that the temperature drift is further reduced. be able to.
As shown in FIGS. 24A and 24B, the rotation detector 10H is also housed in a cylindrical resin case 16 in the same manner as the rotation detector 10. At this time, if the lead frame 24L is bent in the direction perpendicular to the magnetic sensing surface, the lead frame 24L will not contact the resin case 16, so a metal case was used instead of the resin case 16. Even in this case, the problem of signal line contact does not occur.
As shown in FIG. 25, the rotation detector 10H has an optimum structure even when directly connected to a printed circuit board 27 or the like.
In addition, when the four-terminal magnetoresistive element 11M is used for the rotation detector 10H, the lead frame 24L may be extended from both sides as shown in FIG.

なお、実施の形態１〜３では、感磁部１８に加わる磁界の大きさがなるべく均一になるように、永久磁石１２の幅を、感磁部１８の幅よりも大きくは設定しているが、特に大きさについては規定していなかった。しかしながら、実施の形態２で説明した４端子の磁気抵抗素子１１Ｍのように、磁気抵抗素子１８Ａと磁気抵抗素子１８Ｂ、及び、磁気抵抗素子１８Ｃと磁気抵抗素子１８Ｄとが磁石の中心に対して対称に配置されておらず、回転方向に対してＰ／４だけずれている場合には、永久磁石１２の幅を適正に設定する必要がある（図１６，図１７参照）。
すなわち、磁気抵抗素子１８Ａに印加されている磁界の大きさＢＡと磁気抵抗素子１８Ｂに印加されている磁界の大きさＢＢ、及び、磁気抵抗素子１８Ｃに印加されている磁界の大きさＢＣと磁気抵抗素子１８Ｄに印加されている磁界の大きさＢＤとは全く等しくないので、図７に示した抵抗値と磁束密度の関係からもわかるように、印加磁界が異なると抵抗値が異なり、磁気抵抗素子１１Ｍの出力端子１８ａ及び出力端子１８ｂの電位は、Ｖｉｎ／２からずれてしまうことになる。つまり、ＢＡ≠ＢＢのため、磁気抵抗素子１８Ａの抵抗値をＲＡ、磁気抵抗素子１８Ｂの抵抗値ＲＢとすると、ＲＡ≠ＲＢとなってしまう（磁気抵抗素子１８Ｃ，１８Ｄについても同様に、ＲＣ≠ＲＤとなる）。このとき、感磁部１８の幅Ｗに比べて永久磁石１２の幅Ｗｍをかなり大きくすると、ほぼＢＡ＝ＢＢとすることができるが、回転検出器１０の大きさの制限もあり、永久磁石１２の幅Ｗｍも制限されることになる。 In the first to third embodiments, the width of the permanent magnet 12 is set larger than the width of the magnetic sensing portion 18 so that the magnitude of the magnetic field applied to the magnetic sensing portion 18 is as uniform as possible. The size was not specified. However, like the 4-terminal magnetoresistive element 11M described in the second embodiment, the magnetoresistive element 18A and the magnetoresistive element 18B, and the magnetoresistive element 18C and the magnetoresistive element 18D are symmetrical with respect to the center of the magnet. If it is not arranged at the position and is shifted by P / 4 with respect to the rotation direction, it is necessary to set the width of the permanent magnet 12 appropriately (see FIGS. 16 and 17).
That is, the size B B of the magnetic field applied to the size B A and the magnetoresistive element 18B of the magnetic field applied to the magnetoresistive element 18A, and, the magnetic field applied to the magnetoresistive element 18C size B Since C and the magnitude BD of the magnetic field applied to the magnetoresistive element 18D are not equal to each other, as can be seen from the relationship between the resistance value and the magnetic flux density shown in FIG. Unlike, the potential of the output terminal 18a and output terminal 18b of the magnetoresistive element 11M would deviate from V in / 2. That is, since the B A ≠ B B, the resistance value of the magnetoresistive element 18A R A, when the resistance R B of the magnetoresistive element 18B, R A ≠ becomes R B (magneto-resistive element 18C, the 18D likewise, the R C ≠ R D). At this time, the considerably increasing the width W m of the permanent magnet 12 than the width W of the magnetic sensing part 18, approximately B A = may be a B B, there are also limitations in the size of the rotation detector 10, width W m of the permanent magnet 12 is also limited.

そこで、図１６及び図１７に示した４端子の磁気抵抗素子１１Ｍにおいて、端子電極１９ａ，１９ｂ間に直列電源Ｖｉｎ（＝５Ｖ）を接続したときの永久磁石１２の幅と出力端子１９Ｍ（あるいは１９Ｎ）のオフセット電圧（Ｖｉｎ／２からのずれ）との関係、及び、永久磁石１２の幅と感磁部１８の幅との差（磁石の端面と感磁部の端面との距離の２倍）とオフセット電圧との関係を、磁界解析計算で見積もった結果をそれぞれ、図２７及び図２８に示す。
なお、この例では、感磁部１８の幅を２．４ｍｍとし、磁石のサイズは、４．５ｍｍ×Ｗ（歯車の回転方向の幅）×４．５ｍｍ（厚さ：感磁面に垂直方向）とし、Ｗを３．５ｍｍ〜５．５ｍｍまで変化させた。
ここで、オフセット電圧は、ｅｏｆｆ＝｛ＲＢ／（ＲＡ＋ＲＢ）｝×Ｖｉｎ―（Ｖｉｎ／２）である。
図２７から、磁石の幅が、４．５ｍｍになると、オフセット電圧は４０ｍＶ以下になることがわかる。また、図２８から、磁石の幅が感磁部の幅に比べて２ｍｍ以上大きいとき、オフセット電圧は４０ｍＶ以下にできることがわかる。
したがって、永久磁石１２の端面と感磁部１８の端面との距離を１ｍｍ以上とすることにより、オフセット電圧を４０ｍＶ以下にすることができる。なお、永久磁石１２の幅の上限については、回転検出器の大きさにより適宜決定される。 Therefore, in the four-terminal magnetoresistive element 11M shown in FIGS. 16 and 17, the width of the permanent magnet 12 when the series power source V in (= 5 V) is connected between the terminal electrodes 19a and 19b and the output terminal 19M (or 19N) and the difference between the offset voltage (deviation from V in / 2) and the difference between the width of the permanent magnet 12 and the width of the magnetic sensing portion 18 (2 of the distance between the end surface of the magnet and the end surface of the magnetic sensing portion). (Times) and the offset voltage are shown in FIGS. 27 and 28, respectively.
In this example, the width of the magnetic sensing portion 18 is 2.4 mm, and the size of the magnet is 4.5 mm × W (width in the rotation direction of the gear) × 4.5 mm (thickness: perpendicular to the magnetic sensing surface). ) And W was changed from 3.5 mm to 5.5 mm.
Here, the offset voltage is e off = {R B / (R A + R B )} × V in − (V in / 2).
FIG. 27 shows that the offset voltage is 40 mV or less when the magnet width is 4.5 mm. Further, FIG. 28 shows that the offset voltage can be made 40 mV or less when the width of the magnet is 2 mm or more larger than the width of the magnetic sensitive part.
Therefore, the offset voltage can be reduced to 40 mV or less by setting the distance between the end face of the permanent magnet 12 and the end face of the magnetic sensing portion 18 to 1 mm or more. Note that the upper limit of the width of the permanent magnet 12 is appropriately determined depending on the size of the rotation detector.

以下、実施例により本発明を詳細に説明するが、本発明の磁気抵抗素子及び回転検出器は下記に限定されるものではない。
[実施例１]
薄膜形成法の一例として分子線エピタキシー法を用いて、半絶縁性のＧａＡｓ単結晶基板の（１００）面上に、ＳｎドープＩｎＳｂ薄膜をエピタキシャル成長させた。
まず、厚さ０．３５ｍｍの半絶縁性のＧａＡｓ単結晶基板にＡｓを照射しながら、６５０℃で加熱し表面酸素を脱離させる。次に、５８０℃で温度を下げてＧａＡｓバッファ層を２００ｎｍの厚さで形成する。次に、Ａｓを照射しながら４００℃まで温度を下げた後、ＳｎとＩｎ、Ｓｂを同時に基板に照射しながら化合物半導体薄膜の膜厚１μｍからなるＳｎドープＩｎＳｂ単結晶薄膜を形成した。この際、ＩｎＳｂ単結晶薄膜の電子濃度は、７×１０１６ｃｍ−３になるようにＳｎセル温度を調節した。成膜したＩｎＳｂ単結晶薄膜の電気特性を測定したところ、電子濃度は７×１０１６ｃｍ−３、電子移動度は４０，０００ｃｍ2／Ｖｓであった。
次に、ＩｎＳｂ／ＧａＡｓ基板のＩｎＳｂ表面にフォトレジストをスピンコータで均一に塗布する。フォトレジストの塗布条件は、１００ｃｐの粘度で３２００ｒｐｍの回転速度で２０秒間回転すると２．５μｍの厚さとなる。ＩｎＳｂのメサエッチング用のフォトマスクを用いて、露光・現像した後に塩酸・過酸化水素系のエッチング液で所望の形状にＩｎＳｂ薄膜をメサエッチングした。
その後、再度、フォトレジストを塗布した後に、短絡電極を形成するための露光・現像を行い、真空蒸着法により電極を蒸着し、リフトオフ法で短絡電極を形成した。詳細には、フォトレジストによりレジストパターンを形成した後に、電子ビーム法により短絡電極として５０ｎｍ厚のＴｉと４００ｎｍ厚のＡｕ、さらに５０ｎｍ厚のＮｉからなる積層電極を形成し、リフトオフ法を用いて所望の短絡電極を形成した。
更に、保護膜として窒化シリコン薄膜を３００ｎｍの厚さでプラズマＣＶＤ法により形成し、端子電極部分のみの窒化シリコン膜を、反応性イオンエッチング装置を用いて除去し、最後に短絡電極の形成方法と同様にして、端子電極を形成した。端子電極として５０ｎｍ厚のＴｉと４００ｎｍ厚のＡｕからなる積層電極とした。化合物半導体薄膜からなる動作層との接触を改善するために、不活性ガス雰囲気で５００℃×２分間の熱処理を行った。
このようにして化合物半導体薄膜を感磁部とし、端子電極３個を有し、この端子電極間に複数の短絡電極を有する、図４の磁気抵抗素子１１と同様の構成の磁気抵抗素子を、フォトリソグラフィーを応用した微細加工プロセスの応用により、１枚のウエーハ上に多数製作した。なお、感磁部の間隔は、検出する歯車の山と谷の間隔に合わせた。 EXAMPLES Hereinafter, although an Example demonstrates this invention in detail, the magnetoresistive element and rotation detector of this invention are not limited to the following.
[Example 1]
As an example of the thin film formation method, a Sn-doped InSb thin film was epitaxially grown on the (100) plane of a semi-insulating GaAs single crystal substrate using a molecular beam epitaxy method.
First, surface oxygen is desorbed by heating at 650 ° C. while irradiating a semi-insulating GaAs single crystal substrate having a thickness of 0.35 mm with As. Next, the temperature is lowered at 580 ° C. to form a GaAs buffer layer with a thickness of 200 nm. Next, the temperature was lowered to 400 ° C. while irradiating As, and then a Sn-doped InSb single crystal thin film having a film thickness of 1 μm was formed while simultaneously irradiating the substrate with Sn, In, and Sb. At this time, the Sn cell temperature was adjusted so that the electron concentration of the InSb single crystal thin film was 7 × 10 16 cm −3 . Measurement of the film-formed InSb electrical characteristics of the single-crystal thin film, the electron concentration of 7 × 10 16 cm -3, the electron mobility was 40,000 cm 2 / Vs.
Next, a photoresist is uniformly applied to the InSb surface of the InSb / GaAs substrate by a spin coater. The photoresist coating condition is 2.5 μm when rotated for 20 seconds at a rotational speed of 3200 rpm with a viscosity of 100 cp. Using an InSb mesa etching photomask, the InSb thin film was mesa-etched into a desired shape with a hydrochloric acid / hydrogen peroxide etching solution after exposure and development.
Then, after applying a photoresist again, exposure and development for forming a short-circuit electrode were performed, an electrode was deposited by a vacuum deposition method, and a short-circuit electrode was formed by a lift-off method. Specifically, after forming a resist pattern with a photoresist, a stacked electrode made of 50 nm thick Ti, 400 nm thick Au, and 50 nm thick Ni is formed as a short-circuit electrode by an electron beam method, and desired using a lift-off method. The short-circuit electrode was formed.
Furthermore, a silicon nitride thin film having a thickness of 300 nm is formed as a protective film by plasma CVD, and the silicon nitride film only on the terminal electrode portion is removed using a reactive ion etching apparatus. Similarly, a terminal electrode was formed. As the terminal electrode, a laminated electrode made of Ti having a thickness of 50 nm and Au having a thickness of 400 nm was used. In order to improve the contact with the operation layer made of the compound semiconductor thin film, a heat treatment was performed at 500 ° C. for 2 minutes in an inert gas atmosphere.
A magnetoresistive element having the same configuration as that of the magnetoresistive element 11 in FIG. 4, having the compound semiconductor thin film as a magnetic sensing portion, having three terminal electrodes, and having a plurality of short-circuit electrodes between the terminal electrodes, Many were fabricated on one wafer by applying a microfabrication process using photolithography. The interval between the magnetic sensing portions was adjusted to the interval between the peaks and valleys of the detected gear.

次に、モールド樹脂による圧力や面内応力を緩和するため、磁気抵抗素子の感磁部面上に、上記部位を覆うように、柔らかいシリコン樹脂から成る軟質樹脂層を形成した。
その後、ダイシングにより個別の磁気抵抗素子に切離した。こうして製作した磁気抵抗素子チップを、リードフレームを利用して、ボンデングパッケージをした。具体的には、ち、リードフレームのアイランド上に磁気抵抗素子チップを、ダイボンダーを用いダイボンドし、次いで、３０μｍの金ワイヤーにより磁気抵抗素子の３個の端子とリード間を、ワイヤーボンダーを用いワイヤーボンドした後、トランスファーモールド法によりエポキシ樹脂によりパッケージした。その後、タイバーカット、リードカットにより、及びリードのフォーミングを行い、最後に、パッケージされた磁気抵抗素子を永久磁石が保持された磁石ホルダーとともに円筒状の樹脂ケースに収納し、全体が円柱状である回転検出器を作製した。
図２９（ａ），（ｂ）は作製された３端子の磁気抵抗素子１１の構成を示す図で、図３０は磁束密度０．２５テスラのもとでの温度ドリフトを示す図である。図３０の横軸は温度、縦軸は信号出力電圧Ｖｏｕｔから電源電圧の半分（Ｖｉｎ／２）を差し引いたもの（以下、オフセット電圧と称する）である。図２９（ａ），（ｂ）において、２個の磁気抵抗素子１８ａ，１８ｂの抵抗値及びその温度変化が等しい場合は、信号出力電圧Ｖｏｕｔは、Ｖｏｕｔ＝Ｖｉｎ／２となる。
図３０から明らかなように、本例の磁気抵抗素子１１は、信号出力電圧Ｖｏｕｔの温度ドリフトがほとんどない、優れた温度依存性を示している。このことは、感磁部の全面に渉り、磁界の印加された状態の抵抗値の温度依存性が均一であること意味しており、半絶縁性のＧａＡｓ単結晶から成る絶縁性基板上に、ＳｎドープＩｎＳｂ薄膜を分子線エピタキシー法により成長させ、これを感磁部とした磁気抵抗素子は、各素子の特性も揃っており、かつ、温度依存性が極めて小さいことが確認された。 Next, in order to relieve the pressure and in-plane stress due to the mold resin, a soft resin layer made of a soft silicon resin was formed on the magnetically sensitive part surface of the magnetoresistive element so as to cover the above-mentioned part.
Thereafter, it was separated into individual magnetoresistive elements by dicing. The thus produced magnetoresistive element chip was bonded using a lead frame. Specifically, the magnetoresistive element chip is die-bonded on the island of the lead frame using a die bonder, and then the wire between the three terminals of the magnetoresistive element and the lead is formed using a wire bonder with a 30 μm gold wire. After bonding, it was packaged with an epoxy resin by a transfer mold method. After that, tie bar cutting, lead cutting, and lead forming are performed. Finally, the packaged magnetoresistive element is housed in a cylindrical resin case together with a magnet holder holding a permanent magnet, and is entirely cylindrical. A rotation detector was fabricated.
FIGS. 29A and 29B are diagrams showing the configuration of the manufactured three-terminal magnetoresistive element 11, and FIG. 30 is a diagram showing a temperature drift under a magnetic flux density of 0.25 Tesla. The horizontal axis of FIG. 30 is temperature, and the vertical axis is half the power supply voltage from the signal output voltage V out (V in / 2) minus (hereinafter, referred to as the offset voltage). In FIG. 29 (a), (b) , 2 pieces of the magnetoresistive element 18a, when the resistance and the temperature variation of 18b are equal, the signal output voltage V out becomes V out = V in / 2.
As apparent from FIG. 30, the magneto-resistive element 11 of this embodiment, there is little temperature drift of the signal output voltage V out, it shows excellent temperature dependence. This means that the temperature dependence of the resistance value in a state where a magnetic field is applied is uniform over the entire surface of the magnetosensitive portion, and is formed on an insulating substrate made of a semi-insulating GaAs single crystal. It was confirmed that the magnetoresistive element in which the Sn-doped InSb thin film was grown by the molecular beam epitaxy method and used as the magnetosensitive part has the characteristics of each element and has extremely low temperature dependence.

［比較例１］
Ｓｎのドーピングを行わずにＩｎＳｂ単結晶薄膜を形成したことと、磁気抵抗素子の感磁面上に、柔らかいシリコン樹脂から成る軟質樹脂層を形成していないことを除けば、実施例１同様にして磁気抵抗素子を作製し、その後回転検出器を作製した。
この場合も、図２９（ａ），（ｂ）に示すように、３端子の磁気抵抗素子を作製し、磁束密度０．２５テスラのもとで温度ドリフトを測定した。その結果を図３１に示す。図３１の横軸は温度、縦軸はオフセット電圧である。図３１からわかるように、Ｓｎのドーピングがなく、更に、軟質樹脂層が形成されていない磁気抵抗素子では、温度が０℃以下になると、かなりの温度ドリフトが見られる。 [Comparative Example 1]
The same as in Example 1 except that the InSb single crystal thin film was formed without doping Sn and the soft resin layer made of soft silicon resin was not formed on the magnetosensitive surface of the magnetoresistive element. Thus, a magnetoresistive element was manufactured, and then a rotation detector was manufactured.
Also in this case, as shown in FIGS. 29A and 29B, a three-terminal magnetoresistive element was manufactured, and the temperature drift was measured under a magnetic flux density of 0.25 Tesla. The result is shown in FIG. In FIG. 31, the horizontal axis represents temperature, and the vertical axis represents offset voltage. As can be seen from FIG. 31, in the magnetoresistive element which is not doped with Sn and in which the soft resin layer is not formed, a considerable temperature drift is observed when the temperature is 0 ° C. or lower.

［比較例２］
Ｓｎのドーピングを行わずにＩｎＳｂ単結晶薄膜を形成したことを除けば、実施例１同様にして磁気抵抗素子を作製し、その後回転検出器を作製した。
この場合も、図２９（ａ），（ｂ）に示すように、３端子の磁気抵抗素子を作製し、磁束密度０．２５テスラのもとで温度ドリフトを測定した。その結果を図３２に示す。図３２の横軸は温度、縦軸はオフセット電圧である。図３２からわかるように、軟質樹脂層が形成されていてもＳｎのドーピングがない磁気抵抗素子では、比較例１に比べると、オフセット電圧の温度ドリフトはかなり抑制されているが、やはり温度が０℃以下になると、温度ドリフトが見られる。 [Comparative Example 2]
A magnetoresistive element was manufactured in the same manner as in Example 1 except that an InSb single crystal thin film was formed without doping Sn, and then a rotation detector was manufactured.
Also in this case, as shown in FIGS. 29A and 29B, a three-terminal magnetoresistive element was manufactured, and the temperature drift was measured under a magnetic flux density of 0.25 Tesla. The result is shown in FIG. In FIG. 32, the horizontal axis represents temperature, and the vertical axis represents offset voltage. As can be seen from FIG. 32, in the magnetoresistive element in which the soft resin layer is formed and there is no Sn doping, the temperature drift of the offset voltage is considerably suppressed as compared with Comparative Example 1, but the temperature is still 0. Temperature drift is seen below ℃.

[実施例２]
実施例１と同様にして、図１６に示すような、４個の磁気抵抗素子をループ状に接続した４端子磁気抵抗素子１１Ｍを作製し、ダイシングにより個別の磁気抵抗素子に切離した。チップサイズは３．２ｍｍ×２．２ｍｍであり、１つのチップ上には、４個の磁気抵抗素子が作製されている。磁気抵抗素子の作製プロセスは、通常のフォトリソグラフィーの技術を用いているため、磁気抵抗素子の間隔は、量産されるすべての素子で精度よく再現できる。
次に、図１と同様の磁石ホルダー１５に２個のＳｍＣｏ磁石（永久磁石１２）を左側から挿入し、端子ピン１３も挿入した。磁石の磁化方向は感磁部１８を構成する化合物半導体薄膜の面に垂直である。磁石のサイズは、４．５ｍｍ×５．５ｍｍ（歯車の回転方向の幅）×４．５ｍｍ（厚さ：感磁面に垂直方向）である。用いた磁石の表面での磁束密度は、約０．２５Ｔであった。その後、プリント基板に図１２の構造で、図１８，１９に示した４端子磁気抵抗素子１１Ｓ，１１Ｚを半田付けした。磁気抵抗素子１１Ｓは、Ａ／Ｂ相用であり、磁気抵抗素子１１ＺはＺ相である。そして、端子ピン４を図示しないプリント基板に接続した後、磁石ホルダー１５を、円筒状の樹脂ケース１６に挿入し、樹脂ポッティングにより固定した。こうして樹脂ケース１６および薄い金属板（真鍮薄板）１４のフタで全体が保護されている回転検出器を完成した。上記樹脂ケース１６は、図１に示すものと同様に、一端が厚さ０．１５ｍｍの真鍮薄板１４のフタを有し、対抗する一端が開口部である。 [Example 2]
In the same manner as in Example 1, a four-terminal magnetoresistive element 11M in which four magnetoresistive elements were connected in a loop shape as shown in FIG. 16 was manufactured and separated into individual magnetoresistive elements by dicing. The chip size is 3.2 mm × 2.2 mm, and four magnetoresistive elements are fabricated on one chip. Since the manufacturing process of the magnetoresistive element uses a normal photolithography technique, the distance between the magnetoresistive elements can be accurately reproduced in all the mass-produced elements.
Next, two SmCo magnets (permanent magnets 12) were inserted into the magnet holder 15 similar to FIG. 1 from the left side, and the terminal pins 13 were also inserted. The magnetization direction of the magnet is perpendicular to the surface of the compound semiconductor thin film constituting the magnetosensitive portion 18. The size of the magnet is 4.5 mm × 5.5 mm (width in the rotation direction of the gear) × 4.5 mm (thickness: direction perpendicular to the magnetic sensitive surface). The magnetic flux density on the surface of the magnet used was about 0.25T. Thereafter, the four-terminal magnetoresistive elements 11S and 11Z shown in FIGS. 18 and 19 were soldered to the printed circuit board with the structure of FIG. The magnetoresistive element 11S is for the A / B phase, and the magnetoresistive element 11Z is for the Z phase. And after connecting the terminal pin 4 to the printed circuit board which is not shown in figure, the magnet holder 15 was inserted in the cylindrical resin case 16, and was fixed by resin potting. In this way, a rotation detector, which was entirely protected by the lid of the resin case 16 and the thin metal plate (brass thin plate) 14, was completed. As in the case shown in FIG. 1, the resin case 16 has a lid of a brass thin plate 14 having a thickness of 0.15 mm, and the opposite end is an opening.

このようにして完成した回転検出器のＶｉｎ端子ピンとＧＮＤ端子ピンの間に、直流電源５Ｖを接続し、実際の歯車（ＪＩＳ規格Ｂ１７０１−１円筒歯車インボリュート歯車ｐ＝０．８π）を回転させて、出力信号を観測した。今回使用した歯車は、図１８に示すように、１歯欠歯しているものを用いた。そして、出力信号波形より、Ａ相とＢ相は９０°位相がずれていることを確認し、Ｚａ相で欠歯を検出していることも確認できた。出力信号振幅Ｖｐｐは、約３００ｍＶであった。
本発明の回転検出器の温度特性を測定するために、回転機構と回転検出器を恒温槽の中に入れ、図３３に示すように、Ａ相の出力信号振幅Ｖｐｐと、Ａ相のＤＣ電圧ｅを測定した結果を図３４、図３５にそれぞれ示す。なお、図３３では、図を見易くするため、振幅変化と温度ドリフトを大きめにしてある。
図３４での縦軸は、Ａ相の出力信号振幅であり、図３５での縦軸はＡ相のＤＣ電圧ｅのＶｉｎ／２からのずれ（オフセット電圧）を示したもので、温度を−２０℃〜１４０℃まで変化させても、出力信号振幅およびオフセット電圧ともにほとんど変化ないことがわかる。これは、非常に安定して、回転検出が可能であることを意味している。 Between V in terminal pin and GND terminal pins of the rotation detector completed in this manner, by connecting the DC power supply 5V, rotate the actual gear (JIS Standard B1701-1 cylindrical gears involute gear p = 0.8π) The output signal was observed. As shown in FIG. 18, the gear used this time was one with one tooth missing. From the output signal waveform, it was confirmed that the phases A and B were 90 ° out of phase, and it was also confirmed that missing teeth were detected in the Za phase. The output signal amplitude V pp was about 300 mV.
In order to measure the temperature characteristics of the rotation detector of the present invention, the rotation mechanism and the rotation detector are placed in a thermostat, and as shown in FIG. 33, the output signal amplitude V pp of the A phase and the DC of the A phase The results of measuring the voltage e are shown in FIGS. 34 and 35, respectively. In FIG. 33, the amplitude change and the temperature drift are increased in order to make the drawing easier to see.
The vertical axis in FIG. 34 is an output signal amplitude of the A-phase, the vertical axis in FIG. 35 shows the shift (offset voltage) from V in / 2 of DC voltage e of the A-phase, the temperature It can be seen that both the output signal amplitude and the offset voltage hardly change even when the temperature is changed from −20 ° C. to 140 ° C. This means that the rotation can be detected very stably.

[実施例３]
回転検出器（図１６）を３０個作製し、図３６（ａ）に示すように歯車１を回転させて、歯車と回転検出器とのギャップＧを変化させて、出力信号振幅を測定した結果を図３６（ｂ）に示す。測定は、室温にて行った。個体差が非常に小さいことがわかる。 [Example 3]
Results of measuring 30 output detectors by producing 30 rotation detectors (FIG. 16), rotating the gear 1 as shown in FIG. 36 (a), and changing the gap G between the gear and the rotation detector. Is shown in FIG. The measurement was performed at room temperature. It can be seen that the individual difference is very small.

[実施例４]
実施例２と同様にして、図１２に示したタイプの４端子磁気抵抗素子を作製した。実施例２と異なる点は以下である。微細加工プロセスの応用により１枚のウエーハ上に素子を多数製作した後、裏面研磨によってＧａＡｓ基板を０．１ｍｍの厚さにし、その後、接着剤により、厚さ０．２５ｍｍのフェライト基板に貼りあわせた。次に、磁気抵抗素子の感磁部面上に、上記部位を覆うように、柔らかいシリコン樹脂層を形成した後、ダイシングにより個別の磁気抵抗素子に切離した。その後は、実施例１と同様にして磁気抵抗素子を作製し、回転検出器に仕上げた。
この回転検出器を用いて、実施例２と同様に歯車を回転させて、出力信号を観測したところ、出力信号振幅Ｖｐｐは、約３７０ｍＶと、実施例２に比べて出力信号振幅がさらに大きくなった。これにより、磁気誘導層を備えた磁気抵抗素子を用いて回転検出器を作製すれば、出力信号振幅をさらに大きくすることができることが確認された。 [Example 4]
In the same manner as in Example 2, a four-terminal magnetoresistive element of the type shown in FIG. Differences from the second embodiment are as follows. After many devices are fabricated on one wafer by applying microfabrication process, the GaAs substrate is made 0.1 mm thick by backside polishing, and then bonded to a 0.25 mm thick ferrite substrate with an adhesive. It was. Next, a soft silicon resin layer was formed on the magnetosensitive part surface of the magnetoresistive element so as to cover the part, and then separated into individual magnetoresistive elements by dicing. Thereafter, a magnetoresistive element was produced in the same manner as in Example 1, and finished as a rotation detector.
Using this rotation detector, it rotates the gear in the same manner as in Example 2, was observed output signal, the output signal amplitude V pp is about 370 mV, more large output signal amplitude as compared with Example 2 became. As a result, it was confirmed that the output signal amplitude could be further increased if a rotation detector was fabricated using a magnetoresistive element having a magnetic induction layer.

以上説明したように、本発明によれば、温度ドリフトが小さく回転の検出精度の高い回転検出器を実現できるので、工作機械等のスピンドルの回転状態を高精度／高分解能で検出することができるとともに、エレベータ／エスカレータのモータ制御を安定して行うことができる。また、温度特性が極めて良好であるので、例えば、電動射出成形機や自動車のエンジン制御の分野などの高温用途への展開も可能となった。
更に、本発明により、出力信号振幅、オフセット電圧の安定した磁気抵抗素子が製作でき、検出信号の信頼性も向上し、かつ個体差の非常に少ない回転検出器の量産ができる。 As described above, according to the present invention, a rotation detector with small temperature drift and high rotation detection accuracy can be realized, so that the rotation state of a spindle of a machine tool or the like can be detected with high accuracy / high resolution. At the same time, the motor control of the elevator / escalator can be stably performed. In addition, since the temperature characteristics are very good, it has become possible to expand to high temperature applications such as in the field of electric injection molding machines and automobile engine control.
Furthermore, according to the present invention, a magnetoresistive element having a stable output signal amplitude and offset voltage can be manufactured, the reliability of the detection signal can be improved, and mass production of a rotation detector with very little individual difference can be achieved.

本発明の実施の形態１に係る回転検出器の構成を示す断面図である。It is sectional drawing which shows the structure of the rotation detector which concerns on Embodiment 1 of this invention. 本実施の形態１に係る磁気抵抗素子の基本構成を示す断面図である。1 is a cross-sectional view showing a basic configuration of a magnetoresistive element according to a first embodiment. 本実施の形態１に係る３端子の磁気抵抗素子の構成を示す平面図である。FIG. 3 is a plan view showing a configuration of a three-terminal magnetoresistive element according to the first embodiment. ３端子の磁気抵抗素子のモールド後の状態を示す図である。It is a figure which shows the state after a molding of a 3 terminal magnetoresistive element. 化合物半導体薄膜の表面から歯車までの距離Ｇと出力信号振幅との関係を示す図である。It is a figure which shows the relationship between the distance G from the surface of a compound semiconductor thin film to a gearwheel, and an output signal amplitude. 本実施の形態１に係る磁気抵抗素子の作製プロセスを示す図である。It is a figure which shows the manufacturing process of the magnetoresistive element based on this Embodiment 1. FIG. 本発明による磁気抵抗素子の抵抗値の磁束密度依存性を示す図である。It is a figure which shows the magnetic flux density dependence of the resistance value of the magnetoresistive element by this invention. 本発明による磁気抵抗素子の磁気抵抗変化率を示す図である。It is a figure which shows the magnetoresistive change rate of the magnetoresistive element by this invention. 歯車回転検出における３端子の磁気抵抗素子の配置を示す図である。It is a figure which shows arrangement | positioning of the magnetoresistive element of 3 terminals in a gear rotation detection. ３端子の磁気抵抗素子の出力波形を示す図である。It is a figure which shows the output waveform of a 3 terminal magnetoresistive element. 本発明による移動体の検出方法を示す図である。It is a figure which shows the detection method of the moving body by this invention. 本発明による磁気抵抗素子の他の構成を示す図である。It is a figure which shows the other structure of the magnetoresistive element by this invention. 磁気誘導相の形成方法を示す図である。It is a figure which shows the formation method of a magnetic induction phase. Ａ相とＺ相とを出力する回転検出器の構成を示す図である。It is a figure which shows the structure of the rotation detector which outputs A phase and Z phase. Ａ相とＺ相とを出力する磁気抵抗素子の構成とその出力波形とを示す図である。It is a figure which shows the structure of the magnetoresistive element which outputs A phase and Z phase, and its output waveform. 本実施の形態２に係る４端子の磁気抵抗素子の構成を示す図である。It is a figure which shows the structure of the 4-terminal magnetoresistive element which concerns on this Embodiment 2. FIG. ４端子の磁気抵抗素子と歯車の位置関係を示す図である。It is a figure which shows the positional relationship of a 4-terminal magnetoresistive element and a gearwheel. Ａ相／Ｂ相とＺａ相／Ｚｂ相とを出力する回転検出器の構成を示す図である。It is a figure which shows the structure of the rotation detector which outputs A phase / B phase and Za phase / Zb phase. Ａ相／Ｂ相とＺａ相／Ｚｂ相とを出力する磁気抵抗素子の構成とその出力波形とを示す図である。It is a figure which shows the structure of the magnetoresistive element which outputs A phase / B phase, and Za phase / Zb phase, and its output waveform. Ａ相／Ａ−相を出力する磁気抵抗素子の構成を示す平面図である。It is a top view which shows the structure of the magnetoresistive element which outputs A phase / A-phase. Ａ相／Ａ−相を出力する磁気抵抗素子の回路構成を示す図である。It is a figure which shows the circuit structure of the magnetoresistive element which outputs A phase / A-phase. 本実施の形態３に係る永久磁石を一体にした磁気抵抗素子の構成を示す図である。It is a figure which shows the structure of the magnetoresistive element which integrated the permanent magnet which concerns on this Embodiment 3. FIG. 永久磁石と感磁部との位置関係を示す図である。It is a figure which shows the positional relationship of a permanent magnet and a magnetic sensing part. 本実施の形態３に係る回転検出器の構成を示す図である。It is a figure which shows the structure of the rotation detector which concerns on this Embodiment 3. FIG. 本発明による回転検出器の他の構成を示す図である。It is a figure which shows the other structure of the rotation detector by this invention. 本発明による回転検出器の他の構成を示す図である。It is a figure which shows the other structure of the rotation detector by this invention. 永久磁石の幅とオフセット電圧との関係を示す図である。It is a figure which shows the relationship between the width | variety of a permanent magnet, and an offset voltage. 永久磁石の幅と感磁部の幅との差とオフセット電圧との関係を示す図である。It is a figure which shows the relationship between the difference of the width | variety of a permanent magnet and the width | variety of a magnetic sensing part, and offset voltage. 実施例１のオフセット電圧の測定方法を示す図である。FIG. 3 is a diagram illustrating a method for measuring an offset voltage according to the first embodiment. オフセット電圧の温度変化の測定結果を示す図である。It is a figure which shows the measurement result of the temperature change of offset voltage. 比較例１の磁気抵抗素子におけるオフセット電圧の温度変化を示す図である。It is a figure which shows the temperature change of the offset voltage in the magnetoresistive element of the comparative example 1. 比較例２の磁気抵抗素子におけるオフセット電圧の温度変化を示す図である。It is a figure which shows the temperature change of the offset voltage in the magnetoresistive element of the comparative example 2. 実施例２の４端子の磁気抵抗素子の出力信号波形とオフセット電圧を示す図である。It is a figure which shows the output signal waveform and offset voltage of a 4-terminal magnetoresistive element of Example 2. 実施例２の４端子の磁気抵抗素子における出力信号振幅の温度変化を示す図である。It is a figure which shows the temperature change of the output signal amplitude in the 4-terminal magnetoresistive element of Example 2. FIG. 実施例２の４端子の磁気抵抗素子におけるオフセット電圧の温度変化を示す図である。FIG. 6 is a diagram showing a temperature change of an offset voltage in a four-terminal magnetoresistive element of Example 2. 実施例３の回転検出器とのギャップＧと出力信号振幅の実測結果を示す図である。It is a figure which shows the measurement result of the gap G with respect to the rotation detector of Example 3, and an output signal amplitude. 従来の磁気抵抗素子を用いた回転検出器の構造を示す図である。It is a figure which shows the structure of the rotation detector using the conventional magnetoresistive element. 歯車と３端子磁気抵抗素子との位置関係を示す図である。It is a figure which shows the positional relationship of a gearwheel and a 3 terminal magnetoresistive element. 歯車と４端子磁気抵抗素子（Ａ相／Ｂ相の２相出力）との位置関係を示す図である。It is a figure which shows the positional relationship of a gearwheel and a 4-terminal magnetoresistive element (2 phase output of A phase / B phase). 回転検出器からの出力信号の一例を示す図である。It is a figure which shows an example of the output signal from a rotation detector.

符号の説明Explanation of symbols

１ 歯車、２，２ａ〜２ｄ 磁気抵抗素子、３ 永久磁石、４ 直流電源、
５，５ａ，５ｂ 出力端子、
１０ 回転検出器、１１ ３端子の磁気抵抗素子、１２ 永久磁石、
１３ 端子ピン、１４ 薄い金属板、１５ 磁石ホルダー、１６ 樹脂ケース、
１７ 絶縁性基板、１８ 感磁部、１８ａ，１８ｂ，１８Ａ〜１８Ｄ 磁気抵抗素子、
１８Ｆ ＳｎドープＩｎＳｂ薄膜、１９ 端子電極、２０ 短絡電極、
２１ 保護膜、２２ 軟質樹脂層、２３ 金ワイヤー、２４ リードフレーム、
２５ モールド樹脂、２６ 磁気誘導層、２７ プリント基板。 1 gear, 2, 2a to 2d magnetoresistive element, 3 permanent magnet, 4 DC power supply,
5, 5a, 5b output terminal,
10 rotation detector, 11 3-terminal magnetoresistive element, 12 permanent magnet,
13 terminal pin, 14 thin metal plate, 15 magnet holder, 16 resin case,
17 Insulating substrate, 18 Magnetosensitive part, 18a, 18b, 18A-18D Magnetoresistive element,
18F Sn-doped InSb thin film, 19 terminal electrode, 20 short-circuit electrode,
21 protective film, 22 soft resin layer, 23 gold wire, 24 lead frame,
25 Mold resin, 26 Magnetic induction layer, 27 Printed circuit board.

Claims (28)

絶縁基板上に形成された化合物半導体薄膜から成る感磁部と、この感磁部に形成された複数の端子電極とを備えた磁気抵抗素子において、前記化合物半導体薄膜にドナー不純物をドープするとともに、前記感磁部の上部側を、直接または間接に覆う軟質樹脂層を設けたことを特徴とする磁気抵抗素子。   In a magnetoresistive element including a magnetosensitive portion formed of a compound semiconductor thin film formed on an insulating substrate and a plurality of terminal electrodes formed on the magnetosensitive portion, the compound semiconductor thin film is doped with a donor impurity, A magnetoresistive element comprising a soft resin layer that directly or indirectly covers an upper side of the magnetically sensitive portion. 絶縁基板上に形成された感磁部及びこの感磁部に形成された複数の端子電極を備えた磁気抵抗素子と、前記磁気抵抗素子に磁界を印加する手段とを備え、前記磁界を変化させる回転体の回転状態を検出する回転検出器において、前記化合物半導体薄膜にドナー不純物をドープするとともに、前記感磁部の上部側を、直接または間接に覆う軟質樹脂層を設けたことを特徴とする回転検出器。   A magnetoresistive element having a magnetic sensing part formed on an insulating substrate and a plurality of terminal electrodes formed on the magnetic sensing part, and means for applying a magnetic field to the magnetoresistive element, and changing the magnetic field In the rotation detector for detecting the rotation state of the rotating body, the compound semiconductor thin film is doped with a donor impurity, and a soft resin layer that directly or indirectly covers the upper side of the magnetosensitive portion is provided. Rotation detector. 前記軟質樹脂層をシリコン樹脂、または、ゴム系樹脂より構成したことを特徴とする請求項２に記載の回転検出器。   The rotation detector according to claim 2, wherein the soft resin layer is made of silicon resin or rubber-based resin. 前記化合物半導体薄膜の厚さが、０．１〜４．０μｍであることを特徴とする請求項２に記載の回転検出器。   The rotation detector according to claim 2, wherein the compound semiconductor thin film has a thickness of 0.1 to 4.0 μm. 前記軟質樹脂層の厚さが、１〜３００μｍであることを特徴とする請求項２に記載の回転検出器。   The rotation detector according to claim 2, wherein the soft resin layer has a thickness of 1 to 300 μm. 前記軟質樹脂層の上部側を、表面が前記感磁部面に対して平行面となるように、硬質樹脂層により覆うようにしたことを特徴とする請求項２に記載の回転検出器。   The rotation detector according to claim 2, wherein the upper side of the soft resin layer is covered with a hard resin layer so that a surface thereof is parallel to the magnetic sensitive surface. 前記化合物半導体薄膜上に絶縁性無機質材料から成る保護層を設け、この保護層の上に前記軟質樹脂層を形成したことを特徴とする請求項２に記載の回転検出器。   The rotation detector according to claim 2, wherein a protective layer made of an insulating inorganic material is provided on the compound semiconductor thin film, and the soft resin layer is formed on the protective layer. 前記感磁面における磁束密度を、前記感磁部の抵抗値の変化率が５０％以上となる磁束密度としたことを特徴とする請求項２に記載の回転検出器。   The rotation detector according to claim 2, wherein the magnetic flux density on the magnetic sensitive surface is a magnetic flux density at which a rate of change of the resistance value of the magnetic sensitive portion is 50% or more. 前記感磁部の全面に渉り、磁界の印加された状態での抵抗値の温度依存性の均一性が±１．０％以内であることを特徴とする請求項２に記載の回転検出器。   The rotation detector according to claim 2, wherein the uniformity of the temperature dependence of the resistance value in a state where a magnetic field is applied is within ± 1.0% over the entire surface of the magnetic sensing portion. . 前記硬質樹脂層の上に、厚さが０．５ｍｍ以下の金属薄板を配置したことを特徴とする請求項６に記載の回転検出器。   The rotation detector according to claim 6, wherein a metal thin plate having a thickness of 0.5 mm or less is disposed on the hard resin layer. 前記磁界印加手段をＳｍＣｏ磁石としたことを特徴とする請求項２に記載の回転検出器。   The rotation detector according to claim 2, wherein the magnetic field applying means is an SmCo magnet. 前記感磁部を形成する化合物半導体薄膜を、単結晶ＩｎＡｓxＳｂ1-x（０≦ｘ≦１）薄膜としたことを特徴とする請求項２に記載の回転検出器。 The rotation detector according to claim 2, wherein the compound semiconductor thin film forming the magnetosensitive portion is a single crystal InAs x Sb 1-x (0 ≦ x ≦ 1) thin film. 前記絶縁基板の表面に高抵抗層または絶縁層を設け、この上に前記化合物半導体薄膜を形成したことを特徴とする請求項２に記載の回転検出器。   The rotation detector according to claim 2, wherein a high resistance layer or an insulating layer is provided on a surface of the insulating substrate, and the compound semiconductor thin film is formed thereon. 前記化合物半導体薄膜を単結晶ＩｎＳｂ薄膜とするとともに、前記高抵抗層または絶縁層を前記薄膜の結晶構造と同一の結晶構造を有する高抵抗層または絶縁層としたことを特徴とする請求項１３に記載の回転検出器。   14. The compound semiconductor thin film is a single crystal InSb thin film, and the high resistance layer or insulating layer is a high resistance layer or insulating layer having the same crystal structure as the crystal structure of the thin film. The described rotation detector. 前記化合物半導体薄膜を単結晶ＩｎＳｂ薄膜とするとともに、前記高抵抗層または絶縁層と前記薄膜との格子定数の差を２．０％以下としたことを特徴とする請求項１３に記載の回転検出器。   14. The rotation detection according to claim 13, wherein the compound semiconductor thin film is a single crystal InSb thin film, and a difference in lattice constant between the high resistance layer or the insulating layer and the thin film is 2.0% or less. vessel. 前記ドナー不純物を、Ｓｉ，Ｓｎ，Ｓ，Ｓｅ，Ｔｅ，Ｇｅ，Ｃから選ばれる少なくとも１つまたは複数としたことを特徴とする請求項２に記載の回転検出器。   The rotation detector according to claim 2, wherein the donor impurity is at least one or more selected from Si, Sn, S, Se, Te, Ge, and C. 外部接続用の３個の端子電極を有し、２個の磁気抵抗素子が直列に接続された３端子磁気抵抗素子から構成された磁気検出部を備え、前記端子から、Ａ相またはＢ相の非差動出力を得るようにしたことを特徴とする請求項２に記載の回転検出器。   A magnetic detection unit including three terminal electrodes for external connection and including a three-terminal magnetoresistive element in which two magnetoresistive elements are connected in series; The rotation detector according to claim 2, wherein a non-differential output is obtained. 外部接続用の４個の端子電極を有し、４個の磁気抵抗素子がフルブリッジ構造に接続された４端子の磁気抵抗素子から構成された磁気検出部を備え、前記端子から、Ａ相／Ｂ相の非差動２出力を得るようにしたことを特徴とする請求項２に記載の回転検出器。   A magnetic detection unit having four terminal electrodes for external connection and having four terminal magnetoresistive elements connected to each other in a full-bridge structure. 3. The rotation detector according to claim 2, wherein two non-differential outputs of B phase are obtained. 外部接続用の４個の端子電極を有し、４個の磁気抵抗素子がフルブリッジ構造に接続された４端子磁気抵抗素子から構成され、かつ、互いに隣接して接続されていない２対の磁気抵抗素子がそれぞれ同相の磁界変化を受けるように前記各磁気抵抗素子を配置して成る磁気検出部を備え、前記端子から、Ａ相／Ａ−相、あるいは、Ｂ相／Ｂ−相の差動単相出力を得るようにしたことを特徴とする請求項２に記載の回転検出器。   Two pairs of magnets having four terminal electrodes for external connection, four magnetoresistive elements connected to each other in a full bridge structure, and not connected adjacent to each other A magnetic detection unit comprising the magnetoresistive elements arranged so that each of the resistive elements receives a change in magnetic field of the same phase, and a differential of A phase / A-phase or B phase / B-phase from the terminal; The rotation detector according to claim 2, wherein a single-phase output is obtained. 外部接続用の４個の端子電極を有し、４個の磁気抵抗素子がフルブリッジ構造に接続された４端子磁気抵抗素子から構成され、かつ、互いに隣接して接続されていない２対の磁気抵抗素子が同相の磁界変化を受けるように前記各磁気抵抗素子を配置して成る２組の磁気検出部を備え、１組の磁気抵抗素子からはＡ相／Ａ−相の、もう１組の磁気抵抗素子からはＢ相／Ｂ−相の差動２相出力を得るようにしたことを特徴とする請求項２に記載の回転検出器。   Two pairs of magnets having four terminal electrodes for external connection, four magnetoresistive elements connected to each other in a full bridge structure, and not connected adjacent to each other The magnetoresistive elements are arranged so that the resistive elements receive a change in the magnetic field of the same phase, and two sets of magnetic detectors are provided. From one set of magnetoresistive elements, another set of A phase / A-phase is provided. The rotation detector according to claim 2, wherein a differential two-phase output of B phase / B-phase is obtained from the magnetoresistive element. 前記３端子の磁気抵抗素子が１チップ上に形成されていることを特徴とする請求項１７に記載の回転検出器。   The rotation detector according to claim 17, wherein the three-terminal magnetoresistive element is formed on one chip. 前記４端子の非差動の磁気抵抗素子が１チップ上に形成されていることを特徴とする請求項１８に記載の回転検出器。   The rotation detector according to claim 18, wherein the four-terminal non-differential magnetoresistive element is formed on one chip. 前記４端子の差動の磁気抵抗素子が１チップ上に形成されていることを特徴とする請求項１９に記載の回転検出器。   20. The rotation detector according to claim 19, wherein the four-terminal differential magnetoresistive element is formed on one chip. 前記８個の磁気抵抗素子を有する差動の素子が１チップ上に形成されていることを特徴とする請求項２０に記載の回転検出器。   21. The rotation detector according to claim 20, wherein the differential element having the eight magnetoresistive elements is formed on one chip. 前記３端子の磁気抵抗素子を２個備え、一方をＡ相用とし、他方をＺ相用としたことを特徴とする請求項１７に記載の回転検出器。   18. The rotation detector according to claim 17, comprising two of the three-terminal magnetoresistive elements, one for the A phase and the other for the Z phase. 前記４端子の非差動の磁気抵抗素子を２個備え、一方をＡ相／Ｂ相用とし、他方をＺａ相／Ｚｂ相用としたことを特徴とする請求項１８に記載の回転検出器。   19. The rotation detector according to claim 18, comprising two non-differential magnetoresistive elements with four terminals, one for A phase / B phase and the other for Za phase / Zb phase. . 前記４端子の差動の磁気抵抗素子を３個備え、それぞれ、Ａ相／Ａ−相、Ｂ相／Ｂ−相、Ｚ相／Ｚ−相としたことを特徴とする請求項１９に記載の回転検出器。   20. The three-terminal differential magnetoresistive element is provided in three, and each of them is A phase / A-phase, B phase / B-phase, and Z phase / Z-phase, respectively. Rotation detector. 前記８個の磁気抵抗素子を有する差動の素子を１個と、差動の４端子の磁気抵抗素子を１個備え、それぞれ、Ａ相／Ａ−相、Ｂ相／Ｂ−相、Ｚ相／Ｚ−相としたことを特徴とする請求項２０に記載の回転検出器。   One differential element having the eight magnetoresistive elements and one differential four-terminal magnetoresistive element are provided, which are respectively A phase / A-phase, B phase / B-phase, and Z phase. The rotation detector according to claim 20, wherein the rotation detector is a / Z-phase.
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