JP2004289028A

JP2004289028A - Semiconductor device

Info

Publication number: JP2004289028A
Application number: JP2003081710A
Authority: JP
Inventors: Bishiyuku Yamazaki; 美淑山崎; Satoshi Matsuyoshi; 松吉　　聡; Tsutomu Nakajima; 力中島; Shoichi Fukui; 昭一福井
Original assignee: Hitachi Ltd
Current assignee: Hitachi Ltd
Priority date: 2003-03-25
Filing date: 2003-03-25
Publication date: 2004-10-14
Anticipated expiration: 2023-03-25
Also published as: JP4096776B2

Abstract

<P>PROBLEM TO BE SOLVED: To provide a highly reliable semiconductor device by effectively preventing the development of cracking. <P>SOLUTION: The semiconductor device has a lead electrode communicating to leads, a case electrode having a protruded wall part on a circumferential part, a metal plate located through a junction member between the case electrode and a semiconductor chip having a rectifying function and disposed via the lead electrode and the junction member, and a first region thicker than an end part of a lead electrode surface joined with the semiconductor chip via the junction member. The case electrode includes a second region of a region in which the metal plate is disposed, and a third region thinner than the second region, and forms a fourth region of a central part thinner than the metal plate end part such that a protrusion of the second region and a lower surface of the metal plate satisfy a recessed relation. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

【０００１】
【発明の属する技術分野】
本発明は、半導体装置に関するものである。
【０００２】
【従来の技術】
一般的な自動車用オルタネータは、特開平７−１６１８７７号公報に記載されているように、オルタネータの出力を整流する素子である半導体チップを樹脂で封止した構造である。
【０００３】
また、特開平７−２２１２３５号公報には、熱衝撃が多数回反復して加わる激しい環境でも電気的特性が長期間に渡って低下しない半導体装置を得るために、ケース電極と半導体チップとの間に多層構造となった金属板を介在させた構造が記載されている。特開平４−２２９６３９号公報では、半導体チップ部分をエポキシ系絶縁部材にて封止する構造が提案されている。特開平１０−２１５５５２号公報では、絶縁部材を大気圧を超える高圧で充填しモールド成型して絶縁部材に残留圧縮応力を発生させる構造が提案されている。
【特許文献１】
特開平７−１６１８７７号公報
【特許文献２】
特開平７−２２１２３５号公報
【特許文献３】
特開平４−２２９６３９号公報
【特許文献４】
特開平１０−２１５５５２号公報
【０００４】
【発明が解決しようとする課題】
しかし、前記公知例では、亀裂などの欠陥の発生を抑制する形態について検討されているが、一旦欠陥が発生すると十分に進展防止をすることができる形態について検討されていない。
【０００５】
半導体装置の搭載場所が自動車のエンジンルーム内であるため、高熱と、車両側電気負荷の変動により発電機の発熱量増大等の影響が極めて高い。また、特に自動車は、夏冬の温度差によって発生する、広範な温度範囲に及ぶ冷熱の繰り返しを受ける等の厳しい環境下にあるため、熱疲労に強い半導体装置が要求されている。
【０００６】
半導体装置が熱衝撃を多数回反復して受けると、半導体装置を構成する技術の線膨張率の差に起因するひずみがはんだなどの接合部材に加わり、この接合部材にクラックが発生する。クラックが発生すると、通電経路である接合部材の断面積が減少し、電気抵抗が増大することで発熱が増加するとともに、接合部材を通した放熱量も低下し、半導体チップの温度が異常に上昇する。その結果、接合部材の溶融や半導体チップが耐熱限界に達することにより、整流機能が消失し、故障状態となる。
【０００７】
このように半導体チップにはんだなどの接合部材を用いて半導体チップと大きく線膨張率の異なる部材を接合する構造は半導体チップにワイヤボンディングで接合を行う構造に比較し、半導体チップ両面で上記したひずみがはんだなどの接合部材に加わるため、対策が非常に困難であった。
【０００８】
そこで、本発明の目的は、前記課題のいずれかを解決する半導体装置を提供することにある。
【０００９】
【課題を解決するための手段】
前記課題を解決するための形態として例えば、以下の形態をとることができる。
（１）周辺部に壁部を有するケース電極と、前記ケース電極に接合部材を介して設置される整流機能を有する半導体チップと、前記半導体チップに接合部材を介して接続され、リードに連絡するリード電極と、を有し、前記ケース電極の前記接合部材に接合される領域は凸部を有し、前記凸部は前記半導体チップの外周端よりも内側に上端端部が位置されるよう形成されることを特徴とする半導体装置である。
（２）リード電極の下部端部からのクラック発生及び進展防止を図るものである。例えば、周辺部に壁部を有するケース電極と、前記ケース電極に接合部材を介して設置される整流機能を有する半導体チップと、前記半導体チップに接合部材を介して接続され、リードに連絡するリード電極と、を有し、前記リード電極の前記半導体チップ側面における前記接合部材に接合される領域は、周囲より前記半導体チップ側に突出した凸部を有することを特徴とする半導体装置である。
（３）また、中間板を効果的に用いることができる。例えば、周辺部に壁部を有するケース電極と、前記ケース電極に接合部材を介して設置される整流機能を有する半導体チップと、前記半導体チップに接合部材を介して接続され、リードに連絡するリード電極と、を有し、前記ケース電極の前記接合部材に接合される領域は凸部を有し、前記半導体チップと前記ケース電極との間には、前記チップの熱線膨張係数より大きく前記ケース電極の熱線膨張係数より小さい材料から構成された中間板を備え、前記中間板の前記凸部に対向する面には前記凸部を収容する凹部を備えることを特徴とする半導体装置である。
【００１０】
本発明の形態により、効果的にクラックの進展を防止して信頼性の高い半導体装置を提供することができる。車載電子部品として用いる場合は、近年の電子部品増加などによる環境温度上昇があった場合でも、部品点数の増加を抑止して、簡易な構成で寿命を増加することができる。また、本発明によって、製造上の組み立て位置ずれを抑制でき高性能の製品を効率的に製造することができる。
【００１１】
【発明の実施の形態】
以下、本発明の実施の形態を図に基づいて説明する。本発明は、交流発電機の交流出力を直流出力に変換する半導体装置に関する。
【００１２】
図１に示す第１実施形態の半導体装置では、リードに連絡するリード電極１ａと、周辺部に凸壁部を有するケース電極５ａと、リード電極１ａと接合部材２ａを介して配置される整流機能を有する半導体チップ３とケース電極５ａ間に接合部材を介して金属板６ａと、半導体チップ３と接合部材２ａを介して接合されるリード電極面の端部が薄い第一領域１ｂを有し、ケース電極５ａは、金属板６ａが配置される領域の第二の領域５ｄと、第二の領域より薄い第三の領域５ｂを有し、第二の領域面５ｂの凸と金属板下面が凹関係になるように金属板端部より薄い金属板中央部の第四の領域６ｅとを形成されている構造になっている。ケース電極と金属板間の線膨張率差により接合部材に生じるひずみは部材の長さの関係でケース電極側の方が大きい。従って接合部材のケース側に生じるクッラクの進展をケース電極の凸の方で防止できる。また、半導体チップと接合部材を介して接合されるリード電極面の端部が薄い第一領域によって半導体チップと接合部材を介して接合されるリード電極面端部に集中するひずみを分布させひずみ低減に効果があるとともにリード電極面の凸がクラック進展を防止できる。具体的に説明すると、以下のようになる。
【００１３】
通常、リード電極１ａとケース電極５ａと金属板は銅系、あるいは鉄系の金属で形成されている。これらの電極体が例えば銅系で形成されている場合はその線膨張係数が１７ｐｐｍ／℃程度であり、一方、半導体チップの線膨張係数は３ｐｐｍ／℃である。ここで、半導体チップ３とケース電極５ａ間の線膨張率はが大きく、半導体チップ３とケース電極５ａ間の接合部材はケース電極５ａ側ではケース電極と共に変形するが、半導体チップ３側では半導体チップ３によってその変形は押さえられるようになり、接合部材の端部に大きくひずみが発生する。そのために半導体チップとケース電極の線膨張率の中間値を持つ鉄系の金属板６ａを中間板として、ケース電極５と半導体チップ３の間に配置する。熱荷重を繰返し受ける場合に熱ひずみは増加してクラックが発生することを抑制するために、ケース電極５ａを金属板６ａが配置される領域の第二の領域５ｄと、第二の領域より薄い第三の領域５ｂに形成させる。また、第二の領域面５ｂの凸と金属板下面が凹関係になるように金属板端部より薄い金属板中央部の第四の領域６ｅを形成し、クラックの進展が第二領域面５ｂの凸角の所で停止できるようにしている。この事により通電の機能を維持できると共に熱疲労寿命が向上できる。
【００１４】
また、本実施例では、周辺部に壁部を有するケース電極５と、ケース電極５に接合部材を介して設置される整流機能を有する半導体チップ３と、半導体チップ３に接合部材を介して接続され、リードに連絡するリード電極１ａと、を有し、ケース電極５の前記接合部材に接合される領域は凸部を有し、前記凸部は半導体チップ３の外周端よりも内側に上端端部が位置されるよう形成されることを特徴とする。また、凸の径はペレットの径よりも小さくなる。なお、ペレット形状は円、四角、六角、などであってもよい。ベース形状は、ペレットに対応した形状であればよい。これにより、クラックの進展を凸部側壁で止めることができ、信頼性の高い半導体装置を提供することができる。
【００１５】
または、前記凸部の上部面及び側壁面に前記接合部材が配置されるよう形成されるようにすることもできる。なお、凸の径は前述同様に、ペレットの径よりも小さくなる。
【００１６】
また、ケース電極５は第一の厚さの凸状領域と前記凸状領域の周囲に形成される前記第一の厚さより薄い第二の領域とを有し、前記凸状領域の幅は半導体チップより小さくなるよう形成することもできる。
【００１７】
或は、リード電極の下部端部からのクラック発生及び進展防止を図る構造を備える点を特徴とする。特徴点としては、リード電極５の半導体チップ３側面における前記接合部材に接合される領域は、周囲より前記半導体チップ３側に突出した凸部を有する点である。
【００１８】
或は、半導体チップ３と第一の間隔に配置される第一の領域と前記第一の領域の周囲に第一の距離よりも大きい第二の間隔に配置される第二の領域を有する点である。
【００１９】
これにより、接合部材と接する領域複数の凸部が形成されるので応力集中を抑制し、クラックの進展を抑制することができる。
【００２０】
また、中間板である金属板６ａを効果的な形態にすることも特徴の一つである。具体的には、ケース電極５の前記接合部材に接合される領域は凸部を有し、半導体チップ３とケース電極５との間には、前記チップの熱線膨張係数より大きく前記ケース電極の熱線膨張係数より小さい材料から構成された中間板を備え、前記中間板の前記凸部に対向する面には前記凸部を収容する凹部を備える点である。
【００２１】
これにより、リード電極と中間板を接合した後にケース電極と接合しようとする場合のように、中間板をケース電極に接合する場合両者の位置ずれを抑制できる構成にでき、これによる位置ばらつき抑制できる。ひいては寿命のばらつきを抑制できる。
【００２２】
図１に示す第１実施形態の半導体装置では、金属板が銅／インバー（３５％Ｎｉ−Ｆｅの合金）／銅の三層構造の金属板の場合も同じく疲労寿命向上が期待できる。銅／インバー／銅の三層構造の場合、加工が容易である。このように、半導体チップとケース電極の線膨張率の差をカーバできる両部材の線膨張率の中間値にすることで、ひずみ低減に効果があると共に、凹形状に形成するのに加工しやすいので、製造工程を効率化することができる。
【００２３】
また、金属板が銅モリブデンの場合は熱伝導率が良く熱抵抗の低減と同時に疲労寿命向上が期待できる。
【００２４】
図１に示すように第１実施形態の半導体装置の半導体チップ３が配置される領域が凸壁部の高さ以下の位置に形成されることが好ましい。これにより、凸となった壁部は放熱板６ａに接触されているので凸壁部５ｄの高さ以下の位置することによって放熱性が向上できる。
【００２５】
図１に示すように第１実施形態のケース電極５ａ第三領域の幅５ｄは、金属板上面の幅６ｄの３０％以上１００％未満に形成されることが好ましい。これにより、クラック進展が進むと通電経路である接合部材の断面積が減少し、電気抵抗が増大することで発熱が増加するとともに、接合部材２を通した放熱量も低下し、半導体チップ３の温度が異常に上昇することを抑制することができる。そして、その結果、接合部材の溶融や半導体チップ３が耐熱限界に達することにより、整流機能が消失し、故障状態となるのを早い時期に防ぐことができる。このため、ケース電極の第三領域の幅（５ｄ）を大きくし、第三領域凸角でクラック始点近傍を防止できる。また幅が小さいとケース電極の剛性と通電容量に影響及ぼす恐れがあるので、幅は凸の加工可能な範囲で大きく決めることが好ましい。
【００２６】
図３に示すグラフはクラックが進展長さ率［（５ｄ／６ｄ）×１００％］と半導体チップ３の最大温度との関係を示している。これによると第三領域の幅５ｄ凸の角でクラック進展が防止できるので第三領域の幅５ｄは半導体チップの耐熱限界と接合部材の溶融を考えると３５％が最下限値であることがわかる。クラックが面積の１／２以上進展することを抑制することが好ましい。
【００２７】
図１に示すように第１実施形態の半導体装置であって、金属板６ａの第四領域の幅６ｅは、ケース電極５ａ第三領域の幅５ｄの１００％未満（具体的には、たとえば、９０％未満程度であってよい）に形成されることが好ましい。金属板６ａを凹に形成することでケース電極５ａに接合部材２ｃを介して金属板６ａに配置する際のずれ防止なるので組み立てプロセスが容易である。
【００２８】
図１第１実施形態の半導体装置ではケース電極５の凸壁部で囲まれた領域に絶縁部材４充填された領域を有する。例えば、前記絶縁部材４はゴム材からなる。ゴム材としては例えば、軟質性ゴムが好ましく、軟質性ゴム材は常温（２５℃）での剛性が１ＭＰａ〜３ＭＰａであることが好ましい。また、高温（２００℃）でも２ＭＰａ〜４ＭＰａと高温でも物性値の低下はなく、長時間の使用に耐えることができる。また絶縁部材自身の剛性が低いので、絶縁部材によってケース電極の外周部と放熱板を機械的に固定する際にケース電極の変形によって半導体チップに与える応力を低くすことができる。例えば、前記軟質性ゴム材としてシリコンゴムが挙げられる。憂さらに常温ではシリコーンゴムより優れた機械的強度をもつ樹脂などの有機ゴムも、多くは高温下（１５０〜２００℃以上）で強度が低下し、その優劣が逆転じることを考えると、軟質性ゴム材は樹脂などに比べ、絶縁部材の寿命を長くできる。
【００２９】
図１第１実施形態の半導体装置のケース電極はジルコン銅から形成している。これによると、通常，ジルコン銅の降伏応力値４２７ＭＰａで純銅の降伏応力値２０７ＭＰａと２倍以上高いのでケース電極５の外周部５ａと放熱板６を圧入方式で機械的に固定する際にケース電極５の変形が半導体チップ３の変形に及ぼす影響を低減することができる。
【００３０】
図２に第２実施形態の半導体装置を示す。基本的には第１実施形態で説明したのと同様の形態をとることができる。第２実施形態では、ケース電極と半導体チップが接合部材を介して隣接している点が特徴である。具体的には、リード１ａに連絡するリード電極と、周辺部に凸壁部を有するケース電極５ａと、リード電極と接合部材２ａを介して配置される整流機能を有する半導体チップ３と、半導体チップ３と接合部材２ａを介して接合されるリード電極面の端部１ｃより厚い第一領域１ｂを形成し、ケース電極５ａは、半導体チップ３が配置される領域の第二の領域５ｄと、第二の領域５ｄより薄い厚さ５ｆを持つ第三の領域を形成する。第二の領域の幅５ｄは半導体チップの幅３ａ４０％以上１００％未満に形成されている。この実施形態は熱抵抗を低減させるために半導体チップ３と接合部材２ａを介して金属板６ａを設けずにケース電極５ａに直接接合しているので第１実施形態の接合部材に発生するひずみより発生ひずみは大きくなるが、接合部材のケース側に生じるクッラクの進展をケース電極の凸の方で防止できるので熱抵抗の低減とともに熱疲労寿命の向上が期待できる。
【００３１】
また図４に示すグラフはクラックが進展長さ率［（５ｄ／３ａ）×１００％］と半導体チップ３の最大温度との関係を示している。これによると第二領域の幅５ｄ凸の角でクラック進展が防止できるので第二領域の幅５ｄは半導体チップの耐熱限界と接合部材の溶融を考えると４０％が最下限値であることがわかる。従って、第２実施形態の第二の領域の幅５ｄを半導体チップの幅３ａ４０％以上１００％未満に定量的に形成している。
【００３２】
図２第２実施形態の半導体装置も第１実施形態と同じく、ケース電極の凸壁部で囲まれた領域に絶縁部材充填し、ケース電極はジルコン入り銅で形成され、絶縁部材は軟質性ゴム材からなるように形成している。これによって第１実施形態同じ効果が得られる。
【００３３】
図５、図６は第１の実施形態、第２実施形態の半導体装置それぞれが放熱フィンに圧入された後の形態表している。半導体装置の放熱板７と接触しているローレット部分５ｃの凸壁の高さ（Ｈｂ）は、半導体装置の外周側に設置されるための放熱板の厚さ（Ｈａ）以下に形成されることを特徴としている。これによると、半導体装置の搭載場所が自動車のエンジンルーム内の場合、外部からの衝撃などにより放熱板７と固定されている半導体装置が抜けることを防止できる。
【００３４】
図７、図８に示す第３実施形態、第４実施形態の半導体装置では、図１と図２に示す第１実施形態、第２実施形態の半導体装置を放熱板７に固定する際にケース電極５ａと放熱板７を、接合部材２ｄを介して固定している。図５、図６のように半導体装置をケース電極５の径より小さい径の放熱板７穴に圧入方式で固定する場合よりも半導体チップに加わる応力の低減が期待できる。
【００３５】
図７に示す第６実施形態の半導体装置では、請求項１の半導体装置の放熱板６と接触している部分（６ａ）の凸壁の高さ（Ｈｂ）は、半導体装置の外周側に設置されるための放熱板の厚さ（Ｈａ）以下に形成されることを特徴としている。これによると、半導体装置の搭載場所が自動車のエンジンルーム内の場合、外部からの衝撃などにより放熱板６と固定されているケース電極５が抜けることを防止できる。
【００３６】
図８に示す第７実施形態の半導体装置では、図１に示す第１実施形態の半導体装置のケース電極はジルコン銅から形成している。これによると、通常，ジルコン銅の降伏応力値４２７ＭＰａで純銅の降伏応力値２０７ＭＰａと２倍以上高いのでケース電極５の外周部５ａと放熱板６を圧入方式で機械的に固定する際にケース電極５の変形が半導体チップ３の変形に及ぼす影響を低減することができる。
【００３７】
図９第２実施形態の半導体装置を上から見た図を示す。なお、半導体チップ３とケース電極との関係について見れば、第１実施形態に適応することもできる。図９ａは図２に示した形態に適応した例であり、リード１ａに連絡するリード電極と、周辺部に凸壁部を有するケース電極５ａと、リード電極と接合部材２ａを介して配置される整流機能を有する半導体チップ３と、半導体チップ３と接合部材２ａを介して接合されるリード電極面の端部１ｃより厚い第一領域１ｂを形成し、ケース電極５ａは、半導体チップ３が配置される領域の第二の領域５ｄと、第二の領域５ｄより薄い厚さ５ｆを持つ第三の領域を形成する。第二の領域の幅５ｄは円型の半導体チップの幅３ａの４０％以上１００％未満に形成されている。
【００３８】
この実施形態は熱抵抗を低減させるために半導体チップ３と接合部材２ａを介して金属板６ａを設けずにケース電極５ａに直接接合しているので第１実施形態の接合部材に発生するひずみより発生ひずみは大きくなるが、接合部材のケース側に生じるクッラクの進展をケース電極の凸の方で防止できるので熱抵抗の低減とともに熱疲労寿命の向上が期待できる。
【００３９】
また図４に示すグラフはクラックが進展長さ率［（５ｄ／３ａ）×１００％］と半導体チップ３の最大温度との関係を示している。これによると第二領域の幅５ｄ凸の角でクラック進展が防止できるので第二領域の幅５ｄは半導体チップの耐熱限界と接合部材の溶融を考えると４０％が最下限値であることがわかる。従って、第２実施形態の第二の領域の幅５ｄを半導体チップの幅３ａ４０％以上１００％未満に定量的に形成している。
【００４０】
図９ｂの半導体装置ではリード１ａに連絡するリード電極と、周辺部に凸壁部を有するケース電極５ａと、リード電極と接合部材２ａを介して配置される整流機能を有する半導体チップ３と、半導体チップ３と接合部材２ａを介して接合されるリード電極面の端部１ｃより厚い第一領域１ｂを形成し、ケース電極５ａは、半導体チップ３が配置される領域の第二の領域５ｄと、第二の領域５ｄより薄い厚さ５ｆを持つ第三の領域を形成する。第二の領域の幅５ｄは四角型の半導体チップの対角方向幅３ａの４０％以上半導体チップの辺方向幅３ａ‘の１００％未満に形成されている。これは最長幅に基いて規定しても良い。
【００４１】
この実施形態は熱抵抗を低減させるために半導体チップ３と接合部材２ａを介して金属板６ａを設けずにケース電極５ａに直接接合しているので第１実施形態の接合部材に発生するひずみより発生ひずみは大きくなるが、接合部材のケース側に生じるクッラクの進展をケース電極の凸の方で防止できるので熱抵抗の低減とともに熱疲労寿命の向上が期待できる。
【００４２】
図９ｃの半導体装置ではリード１ａに連絡するリード電極と、周辺部に凸壁部を有するケース電極５ａと、リード電極と接合部材２ａを介して配置される整流機能を有する半導体チップ３と、半導体チップ３と接合部材２ａを介して接合されるリード電極面の端部１ｃより厚い第一領域１ｂを形成し、ケース電極５ａは、半導体チップ３が配置される領域の第二の領域５ｄと、第二の領域５ｄより薄い厚さ５ｆを持つ第三の領域を形成する。第二の領域の幅５ｄは六角型の半導体チップの最長方辺向幅３ａの４０％以上半導体チップの最短辺方向幅３ａ‘の１００％未満に形成されている。この実施形態は熱抵抗を低減させるために半導体チップ３と接合部材２ａを介して金属板６ａを設けずにケース電極５ａに直接接合しているので第１実施形態の接合部材に発生するひずみより発生ひずみは大きくなるが、接合部材のケース側に生じるクッラクの進展をケース電極の凸の方で防止できるので熱抵抗の低減とともに熱疲労寿命の向上が期待できる。
【００４３】
また、本発明によれば、接合部材により電気的に接合されたリード電極と半導体チップ、半導体チップと金属板、および金属板とケース電極、部材間の相互の熱変形差から生じる熱疲労によるクラックの進展を防止し熱疲労寿命を向上させると共に、さらに放熱性を考慮した実施形態を形成することで、熱伝達と熱疲労寿命が高い半導体装置を提供できる。
【００４４】
【発明の効果】
本発明により、効果的にクラックの進展を防止して信頼性の高い半導体装置を提供することができる。
【図面の簡単な説明】
【図１】図１は、本発明の第１実施形態を示す半導体装置の要部縦断面図である。
【図２】図２は、本発明の第２実施形態を示す半導体装置の要部縦断面図である。
【図３】図３は、半導体装置において、クラックが進展長さ率と半導体チップに生じる最大温度との関係を示しているグラフ図である。
【図４】図４は、半導体装置において、クラックが進展長さ率と半導体チップに生じる最大温度との関係を示しているグラフ図である。
【図５】図５は、本発明の第１実施形態を示す半導体装置の放熱フィンへの圧入後の縦断面図である。
【図６】図６は、本発明の第２実施形態を示す半導体装置の放熱フィンへの圧入後の縦断面図である。
【図７】図７は、本発明の第３実施形態を示す半導体装置の要部縦断面図である。
【図８】図８は、本発明の第４実施形態を示す半導体装置の要部縦断面図である。
【図９】図９は、本発明の第２実施形態を示す半導体装置を上から見た概要図である。
【符号の説明】
１ａ…リード電極、１ｂ…リード電極の第一領域の幅、１ｃ…リード電極端部の厚さ、２ａ、２ｂ、２ｃ、２ｄ…接合部材（部材がはんだ）３…半導体チップ、３ａ…半導体チップの幅、４…絶縁部材（部材が軟質性ゴム材）、５ａ…ケース電極、５ｂ…ケース電極の第三領域、５ｃ…ケース電極の外周部（ローレット部）、５ｄ…ケース電極の第二領域の幅、５ｅ…ケース電極の第二領域の厚さ、５ｆ…ケース電極の第三領域の厚さ、６ａ…金属板、６ｂ…金属板の第四領域の厚さ、６ｃ…金属板端部の厚さ、６ｄ…金属板の幅、６ｄ…金属板の第四領域の幅、７…放熱板、８…絶縁部材（部材が樹脂）、Ｈａ…ケース電極の高さ、Ｈｂ…放熱フィンの高さ[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a semiconductor device.
[0002]
[Prior art]
A general automotive alternator has a structure in which a semiconductor chip, which is an element for rectifying the output of the alternator, is sealed with a resin, as described in JP-A-7-161877.
[0003]
Japanese Patent Application Laid-Open No. Hei 7-212235 discloses that a semiconductor device whose electrical characteristics do not deteriorate over a long period of time even in a severe environment where a thermal shock is repeatedly applied many times is provided between a case electrode and a semiconductor chip. Describes a structure in which a metal plate having a multilayer structure is interposed. Japanese Patent Application Laid-Open No. H4-222939 proposes a structure in which a semiconductor chip portion is sealed with an epoxy-based insulating member. Japanese Patent Application Laid-Open No. H10-215552 proposes a structure in which an insulating member is filled at a high pressure exceeding atmospheric pressure and molded to generate a residual compressive stress in the insulating member.
[Patent Document 1]
JP-A-7-161877 [Patent Document 2]
Japanese Patent Application Laid-Open No. 7-221235 [Patent Document 3]
Japanese Patent Application Laid-Open No. Hei 4-22939 [Patent Document 4]
JP-A-10-215552
[Problems to be solved by the invention]
However, in the above-mentioned known example, a mode for suppressing the generation of a defect such as a crack is studied, but a mode for preventing the progress once the defect is generated is not studied.
[0005]
Since the mounting location of the semiconductor device is in the engine room of the automobile, the effect of high heat and an increase in the calorific value of the generator due to the fluctuation of the electric load on the vehicle side is extremely high. In particular, since automobiles are in a severe environment such as being subjected to repeated cold and heat over a wide temperature range due to a temperature difference between summer and winter, a semiconductor device that is resistant to thermal fatigue is required.
[0006]
When a semiconductor device is repeatedly subjected to thermal shock many times, a strain caused by a difference in linear expansion coefficient of a technology constituting the semiconductor device is applied to a joining member such as solder, and a crack occurs in the joining member. When cracks occur, the cross-sectional area of the joining member, which is the current path, decreases, and the electrical resistance increases, which increases heat generation, reduces the amount of heat dissipated through the joining member, and abnormally increases the temperature of the semiconductor chip. I do. As a result, the rectifying function is lost due to the melting of the joining member and the heat resistance of the semiconductor chip reaching the heat resistance limit, resulting in a failure state.
[0007]
In this way, the structure in which the semiconductor chip is joined to a member having a large linear expansion coefficient by using a joining member such as solder to the semiconductor chip is compared with the structure in which the semiconductor chip is joined by wire bonding. Was added to the joining members such as solder, so that it was very difficult to take countermeasures.
[0008]
Therefore, an object of the present invention is to provide a semiconductor device that solves any of the above problems.
[0009]
[Means for Solving the Problems]
For example, the following modes can be adopted as modes for solving the above-mentioned problems.
(1) A case electrode having a peripheral wall portion, a semiconductor chip having a rectifying function installed on the case electrode via a bonding member, and connected to the semiconductor chip via a bonding member to communicate with a lead. A lead electrode; and a region of the case electrode joined to the joining member has a convex portion, and the convex portion is formed such that an upper end is located inside an outer peripheral end of the semiconductor chip. A semiconductor device.
(2) Cracks are generated and prevented from spreading from the lower end of the lead electrode. For example, a case electrode having a wall in a peripheral portion, a semiconductor chip having a rectifying function installed on the case electrode via a bonding member, and a lead connected to the semiconductor chip via a bonding member and connected to a lead A region of the lead electrode that is joined to the joining member on the side surface of the semiconductor chip, and has a protrusion protruding from the periphery toward the semiconductor chip.
(3) Further, the intermediate plate can be used effectively. For example, a case electrode having a wall in a peripheral portion, a semiconductor chip having a rectifying function installed on the case electrode via a bonding member, and a lead connected to the semiconductor chip via a bonding member and connected to a lead And a region of the case electrode that is joined to the joining member has a convex portion, and a space between the semiconductor chip and the case electrode that is larger than the linear thermal expansion coefficient of the chip. A semiconductor device comprising: an intermediate plate made of a material having a smaller coefficient of linear thermal expansion; and a concave portion for accommodating the convex portion on a surface of the intermediate plate facing the convex portion.
[0010]
According to the embodiment of the present invention, a highly reliable semiconductor device can be provided by effectively preventing cracks from developing. When used as an in-vehicle electronic component, even if there is an increase in the environmental temperature due to an increase in electronic components in recent years, an increase in the number of components can be suppressed, and the life can be increased with a simple configuration. Further, according to the present invention, it is possible to suppress a displacement of an assembling position in manufacturing and efficiently manufacture a high-performance product.
[0011]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings. The present invention relates to a semiconductor device that converts an AC output of an AC generator into a DC output.
[0012]
In the semiconductor device according to the first embodiment shown in FIG. 1, a lead electrode 1a connected to a lead, a case electrode 5a having a convex wall on the periphery, and a rectifying function arranged via the lead electrode 1a and the joining member 2a. A metal plate 6a between the semiconductor chip 3 and the case electrode 5a with a bonding member via a bonding member, and a first region 1b having a thin end portion of a lead electrode surface bonded to the semiconductor chip 3 via the bonding member 2a, The case electrode 5a has a second region 5d as a region where the metal plate 6a is arranged, and a third region 5b thinner than the second region, and the convex of the second region surface 5b and the lower surface of the metal plate are concave. The structure is such that a fourth region 6e at the center of the metal plate, which is thinner than the end of the metal plate, is formed so as to have a relationship. The strain generated in the joining member due to the difference in linear expansion coefficient between the case electrode and the metal plate is larger on the case electrode side due to the length of the member. Therefore, the crack that occurs on the case side of the joining member can be prevented from protruding on the case electrode. Further, the first region where the end of the lead electrode surface joined to the semiconductor chip via the joining member is thin distributes the strain concentrated at the end of the lead electrode surface joined to the semiconductor chip via the joining member, thereby reducing the strain. And the convexity of the lead electrode surface can prevent the crack from developing. This will be specifically described as follows.
[0013]
Usually, the lead electrode 1a, the case electrode 5a, and the metal plate are formed of a copper-based or iron-based metal. When these electrodes are made of, for example, copper, the linear expansion coefficient is about 17 ppm / ° C., while the linear expansion coefficient of the semiconductor chip is 3 ppm / ° C. Here, the linear expansion coefficient between the semiconductor chip 3 and the case electrode 5a is large, and the joining member between the semiconductor chip 3 and the case electrode 5a deforms together with the case electrode on the case electrode 5a side, but the semiconductor chip 3 on the semiconductor chip 3 side The deformation is suppressed by 3 and a large strain is generated at the end of the joining member. For this purpose, an iron-based metal plate 6a having an intermediate value of the coefficient of linear expansion between the semiconductor chip and the case electrode is disposed between the case electrode 5 and the semiconductor chip 3 as an intermediate plate. The case electrode 5a is thinner than the second region 5d of the region where the metal plate 6a is disposed and the second region 5d in order to suppress the occurrence of cracks due to an increase in thermal strain when a thermal load is repeatedly received. It is formed in the third region 5b. In addition, a fourth region 6e in the center of the metal plate, which is thinner than the end of the metal plate, is formed so that the protrusion of the second region surface 5b and the lower surface of the metal plate have a concave relationship, and the progress of cracks is reduced by the second region surface 5b. It can be stopped at the convex angle of. As a result, the function of current supply can be maintained and the thermal fatigue life can be improved.
[0014]
Further, in this embodiment, the case electrode 5 having a wall in the peripheral portion, the semiconductor chip 3 having a rectifying function installed on the case electrode 5 via a joining member, and connected to the semiconductor chip 3 via a joining member. And a lead electrode 1a connected to a lead, and a region of the case electrode 5 joined to the joining member has a convex portion, and the convex portion is located at an upper end inside the outer peripheral end of the semiconductor chip 3. The part is formed so as to be located. In addition, the diameter of the protrusion is smaller than the diameter of the pellet. Note that the pellet shape may be a circle, a square, a hexagon, or the like. The base shape should just be a shape corresponding to a pellet. Thus, the growth of the crack can be stopped at the side wall of the projection, and a highly reliable semiconductor device can be provided.
[0015]
Alternatively, the joining member may be formed on the upper surface and the side wall surface of the protrusion. In addition, the diameter of the protrusion is smaller than the diameter of the pellet as described above.
[0016]
The case electrode 5 has a convex region having a first thickness and a second region formed around the convex region and having a thickness smaller than the first thickness, and the width of the convex region is a semiconductor. It can be formed to be smaller than a chip.
[0017]
Alternatively, it is characterized in that it has a structure for preventing crack generation and propagation from the lower end of the lead electrode. As a characteristic point, a region of the lead electrode 5 that is bonded to the bonding member on the side surface of the semiconductor chip 3 has a protrusion protruding from the periphery toward the semiconductor chip 3.
[0018]
Alternatively, a point having a first region disposed at a first distance from the semiconductor chip 3 and a second region disposed at a second distance larger than the first distance around the first region. It is.
[0019]
Thereby, since a plurality of convex portions are formed in a region in contact with the joining member, stress concentration can be suppressed, and the development of cracks can be suppressed.
[0020]
Another feature is that the metal plate 6a, which is an intermediate plate, is formed in an effective form. Specifically, a region of the case electrode 5 joined to the joining member has a convex portion, and a heat-ray expansion coefficient of the case electrode between the semiconductor chip 3 and the case electrode 5 is larger than that of the chip. An intermediate plate made of a material having a smaller expansion coefficient is provided, and a surface of the intermediate plate facing the convex portion has a concave portion for accommodating the convex portion.
[0021]
Thus, when joining the intermediate plate to the case electrode, as in the case where the lead electrode and the intermediate plate are joined to the case electrode after joining, the position shift between the two can be suppressed, thereby suppressing the positional variation. . As a result, variation in life can be suppressed.
[0022]
In the semiconductor device of the first embodiment shown in FIG. 1, the improvement of the fatigue life can be similarly expected when the metal plate is a metal plate having a three-layer structure of copper / invar (an alloy of 35% Ni—Fe) / copper. In the case of a three-layer structure of copper / invar / copper, processing is easy. As described above, by setting the difference between the linear expansion coefficients of the semiconductor chip and the case electrode to an intermediate value between the linear expansion coefficients of the two members capable of covering, it is effective in reducing the strain and is easy to process to form a concave shape. Therefore, the manufacturing process can be made more efficient.
[0023]
Further, when the metal plate is made of copper molybdenum, the thermal conductivity is good and the fatigue life can be expected to be improved while the thermal resistance is reduced.
[0024]
As shown in FIG. 1, it is preferable that the region where the semiconductor chip 3 of the semiconductor device of the first embodiment is arranged is formed at a position equal to or lower than the height of the convex wall portion. Thus, since the convex wall portion is in contact with the heat radiating plate 6a, the heat dissipating property can be improved by being located below the height of the convex wall portion 5d.
[0025]
As shown in FIG. 1, the width 5d of the third region of the case electrode 5a of the first embodiment is preferably formed to be 30% or more and less than 100% of the width 6d of the upper surface of the metal plate. As a result, as the crack progresses, the cross-sectional area of the joining member, which is a current-carrying path, decreases, and the electric resistance increases. As a result, heat generation increases, and the amount of heat released through the joining member 2 decreases. An abnormal rise in temperature can be suppressed. As a result, it is possible to prevent the rectifying function from being lost due to the melting of the joining member or the heat resistance of the semiconductor chip 3 reaching the heat-resistant limit, thereby preventing a failure state at an early stage. For this reason, the width (5d) of the third region of the case electrode can be increased, and the vicinity of the crack starting point can be prevented by the third region convex angle. If the width is small, the rigidity and the current carrying capacity of the case electrode may be affected.
[0026]
The graph shown in FIG. 3 shows the relationship between the crack growth length ratio [(5d / 6d) × 100%] and the maximum temperature of the semiconductor chip 3. According to this, crack propagation can be prevented at the convex corners of the third region having a width of 5d. Therefore, considering the heat resistance limit of the semiconductor chip and the melting of the bonding member, it is understood that the lower limit of the width of the third region is 35%. . It is preferable to suppress the crack from developing by ２ or more of the area.
[0027]
As shown in FIG. 1, in the semiconductor device of the first embodiment, the width 6e of the fourth region of the metal plate 6a is less than 100% of the width 5d of the third region of the case electrode 5a (specifically, for example, (May be less than about 90%). By forming the metal plate 6a in a concave shape, it is possible to prevent displacement when the metal plate 6a is disposed on the metal plate 6a via the joining member 2c on the case electrode 5a, so that the assembly process is easy.
[0028]
FIG. 1 In the semiconductor device of the first embodiment, a region surrounded by the convex wall of the case electrode 5 has a region filled with the insulating member 4. For example, the insulating member 4 is made of a rubber material. As the rubber material, for example, a soft rubber is preferable, and the soft rubber material preferably has a rigidity at room temperature (25 ° C.) of 1 MPa to 3 MPa. Even at a high temperature (200 ° C.), even at a high temperature of 2 MPa to 4 MPa, there is no decrease in physical property values, and it can withstand long-term use. Further, since the rigidity of the insulating member itself is low, the stress applied to the semiconductor chip by the deformation of the case electrode when the outer peripheral portion of the case electrode and the heat sink are mechanically fixed by the insulating member can be reduced. For example, silicone rubber is used as the soft rubber material. In addition, organic rubbers such as resins that have better mechanical strength than silicone rubbers at room temperature also have low strength at high temperatures (150-200 ° C or higher), and the softness is considered to be the opposite. The rubber material can extend the life of the insulating member as compared with a resin or the like.
[0029]
FIG. 1 The case electrode of the semiconductor device of the first embodiment is formed of zircon copper. According to this, usually, the yield stress value of zircon copper is 427 MPa and the yield stress value of pure copper is 207 MPa, which is twice or more higher. Therefore, when the outer peripheral portion 5 a of the case electrode 5 and the heat sink 6 are mechanically fixed by the press-fitting method, the case electrode is used. The effect of the deformation of the semiconductor chip 3 on the deformation of the semiconductor chip 3 can be reduced.
[0030]
FIG. 2 shows a semiconductor device according to the second embodiment. Basically, it can take the same form as that described in the first embodiment. The second embodiment is characterized in that the case electrode and the semiconductor chip are adjacent to each other via a bonding member. More specifically, a lead electrode connected to the lead 1a, a case electrode 5a having a convex wall in the periphery, a semiconductor chip 3 having a rectifying function disposed via the lead electrode and the joining member 2a, and a semiconductor chip 3, a first region 1b thicker than the end 1c of the lead electrode surface joined via the joining member 2a is formed. The case electrode 5a has a second region 5d of the region where the semiconductor chip 3 is arranged, and a second region 5d. A third region having a thickness 5f smaller than the second region 5d is formed. The width 5d of the second region is formed to be 40% or more and less than 100% of the width 3a of the semiconductor chip. In this embodiment, the semiconductor chip 3 is directly connected to the case electrode 5a without the metal plate 6a via the bonding member 2a in order to reduce the thermal resistance. Although the generated strain is increased, the cracks generated on the case side of the joining member can be prevented from being protruded by the convex portion of the case electrode, so that the thermal resistance can be reduced and the thermal fatigue life can be improved.
[0031]
Also, the graph shown in FIG. 4 shows the relationship between the crack growth length ratio [(5d / 3a) × 100%] and the maximum temperature of the semiconductor chip 3. According to this, it is possible to prevent crack propagation at the corners of the second region having a width of 5d, so that the lower limit of the width of the second region is 40% in consideration of the heat resistance limit of the semiconductor chip and the melting of the bonding member. . Therefore, the width 5d of the second region of the second embodiment is quantitatively formed to be not less than 40% and less than 100% of the width 3a of the semiconductor chip.
[0032]
2 As in the first embodiment, the semiconductor device of the second embodiment is filled with an insulating member in a region surrounded by the convex wall of the case electrode, the case electrode is formed of copper containing zircon, and the insulating member is formed of a soft rubber. It is formed of a material. Thereby, the same effect as in the first embodiment can be obtained.
[0033]
FIG. 5 and FIG. 6 show the configurations after the semiconductor devices of the first and second embodiments have been press-fitted into the radiation fins. The height (Hb) of the convex wall of the knurl portion 5c in contact with the heat sink 7 of the semiconductor device is formed to be less than the thickness (Ha) of the heat sink to be installed on the outer peripheral side of the semiconductor device. It is characterized by. According to this, when the mounting location of the semiconductor device is in the engine room of the automobile, it is possible to prevent the semiconductor device fixed to the heat sink 7 from coming off due to an external impact or the like.
[0034]
In the semiconductor devices of the third and fourth embodiments shown in FIGS. 7 and 8, a case is used when fixing the semiconductor devices of the first and second embodiments shown in FIGS. The electrode 5a and the heat sink 7 are fixed via the joining member 2d. As shown in FIGS. 5 and 6, a reduction in the stress applied to the semiconductor chip can be expected as compared with the case where the semiconductor device is fixed to the heat radiation plate 7 having a smaller diameter than the case electrode 5 by the press-fitting method.
[0035]
In the semiconductor device of the sixth embodiment shown in FIG. 7, the height (Hb) of the convex wall of the portion (6a) in contact with the heat sink 6 of the semiconductor device of claim 1 is set on the outer peripheral side of the semiconductor device. It is characterized in that the heat sink is formed to have a thickness (Ha) or less. According to this, when the mounting location of the semiconductor device is in the engine room of the automobile, it is possible to prevent the case electrode 5 fixed to the heat sink 6 from coming off due to an external impact or the like.
[0036]
In the semiconductor device of the seventh embodiment shown in FIG. 8, the case electrode of the semiconductor device of the first embodiment shown in FIG. 1 is formed of zircon copper. According to this, usually, the yield stress value of zircon copper is 427 MPa and the yield stress value of pure copper is 207 MPa or more, which is twice or more higher. The effect of the deformation of the semiconductor chip 3 on the deformation of the semiconductor chip 3 can be reduced.
[0037]
9 shows a view of the semiconductor device of the second embodiment as viewed from above. Note that the relationship between the semiconductor chip 3 and the case electrode can be applied to the first embodiment. FIG. 9a is an example adapted to the embodiment shown in FIG. 2, and is arranged via a lead electrode connected to the lead 1a, a case electrode 5a having a convex wall in the peripheral portion, and the lead electrode and the joining member 2a. A semiconductor chip 3 having a rectifying function and a first region 1b thicker than an end 1c of a lead electrode surface joined to the semiconductor chip 3 via a joining member 2a are formed, and the case chip 5a is provided with the semiconductor chip 3. And a third region having a thickness 5f smaller than the second region 5d. The width 5d of the second region is formed to be 40% or more and less than 100% of the width 3a of the circular semiconductor chip.
[0038]
In this embodiment, the semiconductor chip 3 is directly connected to the case electrode 5a without the metal plate 6a via the bonding member 2a in order to reduce the thermal resistance. Although the generated strain is increased, the cracks generated on the case side of the joining member can be prevented from being protruded by the convex portion of the case electrode, so that the thermal resistance can be reduced and the thermal fatigue life can be improved.
[0039]
Also, the graph shown in FIG. 4 shows the relationship between the crack growth length ratio [(5d / 3a) × 100%] and the maximum temperature of the semiconductor chip 3. According to this, it is possible to prevent crack propagation at the corners of the second region having a width of 5d, so that the lower limit of the width of the second region is 40% in consideration of the heat resistance limit of the semiconductor chip and the melting of the bonding member. . Therefore, the width 5d of the second region of the second embodiment is quantitatively formed to be not less than 40% and less than 100% of the width 3a of the semiconductor chip.
[0040]
In the semiconductor device shown in FIG. 9B, a lead electrode connected to the lead 1a, a case electrode 5a having a convex wall portion in the peripheral portion, a semiconductor chip 3 having a rectifying function disposed via the lead electrode and the joining member 2a, A first region 1b thicker than the end 1c of the lead electrode surface joined to the chip 3 via the joining member 2a is formed. The case electrode 5a has a second region 5d where the semiconductor chip 3 is arranged. A third region having a thickness 5f smaller than the second region 5d is formed. The width 5d of the second region is formed to be 40% or more of the diagonal width 3a of the square semiconductor chip and less than 100% of the lateral width 3a 'of the semiconductor chip. This may be defined based on the longest width.
[0041]
In this embodiment, the semiconductor chip 3 is directly connected to the case electrode 5a without the metal plate 6a via the bonding member 2a in order to reduce the thermal resistance. Although the generated strain is increased, the cracks generated on the case side of the joining member can be prevented from being protruded by the convex portion of the case electrode, so that the thermal resistance can be reduced and the thermal fatigue life can be improved.
[0042]
In the semiconductor device shown in FIG. 9C, a lead electrode connected to the lead 1a, a case electrode 5a having a convex wall on the periphery, a semiconductor chip 3 having a rectifying function disposed via the lead electrode and the joining member 2a, and a semiconductor A first region 1b thicker than the end 1c of the lead electrode surface joined to the chip 3 via the joining member 2a is formed. The case electrode 5a has a second region 5d where the semiconductor chip 3 is arranged. A third region having a thickness 5f smaller than the second region 5d is formed. The width 5d of the second region is formed to be 40% or more of the longest side width 3a of the hexagonal semiconductor chip and less than 100% of the shortest side direction width 3a 'of the semiconductor chip. In this embodiment, the semiconductor chip 3 is directly connected to the case electrode 5a without the metal plate 6a via the bonding member 2a in order to reduce the thermal resistance. Although the generated strain is increased, the cracks generated on the case side of the joining member can be prevented from being protruded by the convex portion of the case electrode, so that the thermal resistance can be reduced and the thermal fatigue life can be improved.
[0043]
According to the present invention, the lead electrode and the semiconductor chip, the semiconductor chip and the metal plate, and the metal plate and the case electrode, which are electrically joined by the joining member, cracks due to thermal fatigue caused by a mutual thermal deformation difference between the members. In addition to preventing the development of the semiconductor device and improving the thermal fatigue life, a semiconductor device having high heat transfer and high thermal fatigue life can be provided by forming an embodiment in which heat dissipation is taken into consideration.
[0044]
【The invention's effect】
According to the present invention, it is possible to provide a highly reliable semiconductor device by effectively preventing cracks from developing.
[Brief description of the drawings]
FIG. 1 is a vertical sectional view of a main part of a semiconductor device according to a first embodiment of the present invention;
FIG. 2 is a longitudinal sectional view of a main part of a semiconductor device according to a second embodiment of the present invention.
FIG. 3 is a graph showing a relationship between a growth rate of a crack and a maximum temperature generated in a semiconductor chip in a semiconductor device.
FIG. 4 is a graph showing a relationship between a growth rate of a crack and a maximum temperature generated in a semiconductor chip in a semiconductor device.
FIG. 5 is a vertical cross-sectional view of the semiconductor device according to the first embodiment of the present invention after being press-fitted into radiation fins.
FIG. 6 is a vertical cross-sectional view of a semiconductor device according to a second embodiment of the present invention after being press-fitted into radiation fins.
FIG. 7 is a longitudinal sectional view of a main part of a semiconductor device according to a third embodiment of the present invention.
FIG. 8 is a longitudinal sectional view of a main part of a semiconductor device according to a fourth embodiment of the present invention.
FIG. 9 is a schematic view of a semiconductor device according to a second embodiment of the present invention as viewed from above.
[Explanation of symbols]
1a: Lead electrode, 1b: Width of first region of lead electrode, 1c: Thickness of end of lead electrode, 2a, 2b, 2c, 2d: Joining member (member is solder) 3: Semiconductor chip, 3a: Semiconductor chip Width: 4 ... Insulating member (member is soft rubber material), 5a: Case electrode, 5b: Third region of case electrode, 5c: Outer peripheral portion (knurl portion) of case electrode, 5d: Second region of case electrode 5e thickness of the second region of the case electrode, 5f thickness of the third region of the case electrode, 6a thickness of the fourth region of the metal plate, 6b thickness of the fourth region of the metal plate, 6c end of the metal plate Thickness, 6d: width of the metal plate, 6d: width of the fourth region of the metal plate, 7: heat sink, 8: insulating member (member is resin), Ha: height of case electrode, Hb: heat sink fin height

Claims

A case electrode having a wall in the periphery,
A semiconductor chip having a rectifying function installed on the case electrode via a bonding member,
A lead electrode connected to the semiconductor chip via a bonding member, and connected to a lead,
The region of the case electrode joined to the joining member has a convex portion,
The semiconductor device according to claim 1, wherein the convex portion is formed such that an upper end is located inside an outer peripheral end of the semiconductor chip.

A case electrode having a wall in the periphery,
A semiconductor chip having a rectifying function installed on the case electrode via a bonding member,
A lead electrode connected to the semiconductor chip and connected to a lead,
A semiconductor device, wherein the bonding member is formed on an upper surface and a side wall surface of the protrusion.

A case electrode having a wall in the periphery,
A semiconductor chip having a rectifying function installed on the case electrode via a bonding member,
A lead electrode connected to the semiconductor chip via a bonding member, and connected to a lead,
A semiconductor device, wherein a region of the lead electrode joined to the joining member on a side surface of the semiconductor chip has a protrusion protruding from the periphery toward the semiconductor chip.

A case electrode having a wall in the periphery,
A semiconductor chip having a rectifying function installed on the case electrode via a bonding member,
A lead electrode connected to the semiconductor chip via a bonding member, and connected to a lead,
The region of the case electrode joined to the joining member has a convex portion,
Between the semiconductor chip and the case electrode, an intermediate plate made of a material larger than the coefficient of linear thermal expansion of the chip and smaller than the coefficient of linear thermal expansion of the case electrode,
The semiconductor device according to claim 1, further comprising a concave portion for accommodating the convex portion on a surface of the intermediate plate facing the convex portion.

2. The semiconductor device according to claim 1, wherein a region where said semiconductor chip is arranged is formed at a position equal to or lower than a height of said case wall.

2. The semiconductor device according to claim 1, wherein a width of the case electrode protrusion is formed to be 40% or more and less than 100% of a width of the semiconductor chip.

2. The semiconductor device according to claim 1, wherein a region surrounded by a wall of said case electrode is filled with an insulating member.

5. The semiconductor device according to claim 4, wherein said intermediate plate has a multilayer structure including copper-invar copper.

5. The semiconductor device according to claim 4, wherein said intermediate plate includes a metal material containing copper and molybdenum.