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JP4075199B2 - Power semiconductor module - Google Patents

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Publication number
JP4075199B2
JP4075199B2 JP08547499A JP8547499A JP4075199B2 JP 4075199 B2 JP4075199 B2 JP 4075199B2 JP 08547499 A JP08547499 A JP 08547499A JP 8547499 A JP8547499 A JP 8547499A JP 4075199 B2 JP4075199 B2 JP 4075199B2
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power semiconductor
semiconductor chip
main circuit
electrode
circuit wiring
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JP2000277670A (en
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巧 菊池
弘文 藤岡
敏之 菊永
浩隆 武藤
伸一 木ノ内
修 碓井
健史 大井
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Mitsubishi Electric Corp
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Mitsubishi Electric Corp
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    • H01L24/71—Means for bonding not being attached to, or not being formed on, the surface to be connected
    • H01L24/72—Detachable connecting means consisting of mechanical auxiliary parts connecting the device, e.g. pressure contacts using springs or clips
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    • H01L2224/42—Wire connectors; Manufacturing methods related thereto
    • H01L2224/44—Structure, shape, material or disposition of the wire connectors prior to the connecting process
    • H01L2224/45—Structure, shape, material or disposition of the wire connectors prior to the connecting process of an individual wire connector
    • H01L2224/45001—Core members of the connector
    • H01L2224/45099—Material
    • H01L2224/451—Material with a principal constituent of the material being a metal or a metalloid, e.g. boron (B), silicon (Si), germanium (Ge), arsenic (As), antimony (Sb), tellurium (Te) and polonium (Po), and alloys thereof
    • H01L2224/45117—Material with a principal constituent of the material being a metal or a metalloid, e.g. boron (B), silicon (Si), germanium (Ge), arsenic (As), antimony (Sb), tellurium (Te) and polonium (Po), and alloys thereof the principal constituent melting at a temperature of greater than or equal to 400°C and less than 950°C
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    • H01L2224/4805—Shape
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    • 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
    • H01L2224/484—Connecting portions
    • H01L2224/48475—Connecting portions connected to auxiliary connecting means on the bonding areas, e.g. pre-ball, wedge-on-ball, ball-on-ball
    • H01L2224/48476—Connecting portions connected to auxiliary connecting means on the bonding areas, e.g. pre-ball, wedge-on-ball, ball-on-ball between the wire connector and the bonding area
    • H01L2224/48491—Connecting portions connected to auxiliary connecting means on the bonding areas, e.g. pre-ball, wedge-on-ball, ball-on-ball between the wire connector and the bonding area being an additional member attached to the bonding area through an adhesive or solder, e.g. buffer pad
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    • H01L2224/73—Means for bonding being of different types provided for in two or more of groups H01L2224/10, H01L2224/18, H01L2224/26, H01L2224/34, H01L2224/42, H01L2224/50, H01L2224/63, H01L2224/71
    • H01L2224/732—Location after the connecting process
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    • H01L2924/19107—Disposition of discrete passive components off-chip wires

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  • Engineering & Computer Science (AREA)
  • Computer Hardware Design (AREA)
  • Microelectronics & Electronic Packaging (AREA)
  • Power Engineering (AREA)
  • Cooling Or The Like Of Semiconductors Or Solid State Devices (AREA)

Description

【０００１】
【発明の属する技術分野】
本発明は、モータ等の電気機器の駆動電流を制御する電力変換装置などに用いられるパワー半導体モジュール、さらに詳しくは、パワー半導体モジュールにおけるパワー半導体チップと主回路配線との電気的接続部の構造に関するものである。
【０００２】
【従来の技術】
図７は、従来のパワー半導体モジュールの一例として、汎用のＩＧＢＴ（Ｉｎｓｕｌａｔｅｄ Ｇａｔｅ Ｂｉｐｏｌａｒ Ｔｒａｎｓｉｓｔｏｒ）モジュールの主要部断面模式図を示すものである。図において、１はアルミニウム（Ａｌ）や銅（Ｃｕ）等からなる放熱用ベース板、２は両面にＣｕ等の金属の薄板が接着された、アルミナ、窒化アルミ（ＡｌＮ）等からなる絶縁基板であり、放熱用ベース板上にはんだ等により固定される。絶縁基板２上にはＩＧＢＴ等のパワー半導体チップ３が搭載されている。ＩＧＢＴ３は上面がエミッタ電極４、下面がコレクタ電極５となっており、コレクタ電極５ははんだ等の導電性材料により絶縁基板２上の金属薄板と電気的に接続される。６、７はそれぞれ主回路配線の主要部をなす、エミッタ用およびコレクタ用ブスバーである。各ブスバー６、７は中継基板８と電気的に接続されるとともに、ケース外の外部配線と電気的に接続されている。中継基板８は、絶縁基板と同様、両面にＣｕ等の金属の薄板が接着された絶縁基板であり、放熱用ベース板１上にはんだ等により固定されている。パワー半導体チップ３と中継基板８との間はアルミニウム（Ａｌ）ワイヤボンド９により電気的に接続される。１０はパワー半導体モジュールのケースであり、このケース内部のモジュールはシリコンゲル１１によりモールドされている。
【０００３】
上記のように、従来のパワー半導体モジュールは、パワー半導体チップとブスバーとの電気的接続にＡｌワイヤボンドを用いている。
一方、パワー半導体モジュールの他の電気的接続法として、モジュール外部からの圧力によって、接続される導体の接触面を加圧する圧接法による接続法があり、特に大容量用に採用されている。
以上のように、従来のパワー半導体モジュールでは、パワー半導体チップと主回路配線との電気的接続法として、ワイヤボンドまたは圧接法のいずれかが採用されている。
【０００４】
【発明が解決しようとする課題】
従来のパワー半導体モジュールにおいて、パワー半導体チップと主回路配線との電気的接続にＡｌワイヤボンドを用いた場合、定格５Ａ以下の小容量のモジュールならば運転時の発熱量が小さいためワイヤボンド接続部に問題はあまり起こらないが、それ以上の大容量モジュールになると、運転時の発熱量が大きく、温度サイクルが激しいため、パワー半導体チップとＡｌワイヤボンド部のＡｌとの熱膨張差により生ずる熱ストレスにより、Ａｌワイヤボンド部の接合面の剥離が生じやすく、長期的信頼性に欠ける等の問題があった。
【０００５】
さらに詳しく説明すると、ここで言うところの熱ストレスは、通常の半導体チップを用いたものとは、ストレスモードが大きく異なる。通常の半導体チップでは、チップ自体の発熱量は小さく、主に加わる熱ストレスとしては、アセンブリ工程におけるはんだリフローや信頼性評価試験時におけるヒートショックサイクルといった外的な要因によるものであるのに対して、パワー半導体モジュールにおいて大きな問題となるのは、運転時（大電流通電時）におけるパワー半導体チップ自身の大きな発熱に起因した急峻な温度サイクルが高頻度に発生するために生じる熱ストレスにある。これは、当然大容量のモジュールになるほど重大な問題となってくる。また、電鉄や鉄鋼分野で使用されるような大容量のモジュールでは、このような過酷な使用環境で、２０年から３０年という長期寿命が要求される。
そのため、パワー半導体モジュールでは、通称「パワーサイクル試験」と呼ばれる、パワー半導体チップに断続的に大電流を通電することによって、非常に高速に温度を変化させ、しかもこれを非常に多くの回数、繰り返し行うヒートショックサイクル試験をクリアすることが要求される。
このことは、文献（題名：ＲＥＬＩＡＢＩＬＩＴＹ ＴＥＳＴＩＮＧ ＡＮＤＡＮＡＬＹＳＩＳ ＯＦ ＩＧＢＴ ＰＯＷＥＲ ＭＯＤＵＬＥＳ、著者：Ｐｅｔｅｒ Ｙａｃｏｂ， Ｍａｒｃｅｌ Ｈｅｌｄ， Ｐａｏｌｏ Ｓｃａｃｃｏ， Ｗｕｃｈｅｎ Ｗｕ、出典：ＩＥＥ Ｃｏｌｌｏｑｕｉｕｍ ｏｎ“ＩＧＢＴ ｐｒｏｐｕｌｓｉｏｎ ｄｒｉｖｅｓ”２５ Ａｐｒｉｌ １９９５）にも示されているが、従来のパワー半導体モジュールにおいては、パワーサイクル試験において、△Ｔｊ＝７０℃の条件で、８万回〜２０万回でほとんどがワイヤボンド接続部の接合面剥離モードで破壊していた。なお、ここで、ΔＴｊは１サイクル中でのチップの温度変化である。
【０００６】
一方、前記熱ストレス以外の問題として、パワー半導体モジュールにおいて、チップと主回路配線の電極とをワイヤボンドで接合する方式では、ワイヤの断面積が小さく、また、ワイヤボンドできる本数にも限りがある。そのため、チップ表面に形成された電極（エミッタ電極）を有効に使うことができず、電流の分流特性が悪くなったり、大容量モジュールでは、ワイヤを流れる電流密度が非常に高くなり、過電流により断線する危険性が高くなる。
【０００７】
さらに、パワー半導体モジュールの製造工程においては、ワイヤの接合強度を高めるため、ワイヤボンド時の接合面への加圧力を大きくする傾向にあり、この加圧力が原因で、特にＭＯＳ系半導体チップのようにエミッタ電極面の下にゲート−エミッタ間の絶縁膜が形成されている場合、ゲート−エミッタ間の絶縁不良、チップの破壊などが起こりやすく、歩留まりを低下させるなどの問題もあった。
【０００８】
一方、大容量のパワー半導体モジュールにおいて従来から採用されている圧接法による電気的接続法では、加圧力の変動がモジュールの電気特性に大きな影響を与えるため、メンテナンス性に問題があり、また、この圧接型のパワー半導体モジュールを使ったインバータなどの電力変換装置は、スタック構造等の大がかりな装置になるという問題点があった。
【０００９】
前述のように、パワー半導体モジュールにおいては、パワー半導体チップ自身の発熱による急峻で高頻度な温度変化の繰り返しの下で、パワー半導体チップと銅やアルミニウム等の金属のように線膨張係数が大きく異なっている材料との接続部に、長期間にわたって安定に大電流を通電することが可能な電気的接続を確保する必要があるが、特に近年、パワー半導体モジュールの大容量化やコンパクト化、高速スイッチング化等に伴い、パワー半導体チップの発熱密度が非常に高くなってきており、電気的接続の長期的信頼性の確保は、パワー半導体モジュールにとって最重要課題である。
【００１０】
本発明は、上記のような種々の問題点を解決するためになされたものであり、特に、パワー半導体モジュールに強く要求される電気的接続の長期信頼性を得ることを目的とする。
【００１１】
【課題を解決するための手段】
本発明のパワー半導体モジュールは、ケース内にパワー半導体チップを有するパワー半導体モジュールにおいて、上記パワー半導体チップと主回路配線の電極とを導電性樹脂で電気的に接続するとともに、上記主回路配線の電極を平板電極で構成し、かつ上記主回路配線の電極の、上記パワー半導体チップの中央部分に対向する位置に貫通孔を設け、上記パワー半導体チップを流れる電流が上記パワー半導体チップの中央部分を避けて周辺部分に流れる構造としたものである。
【００１３】
また、本発明のパワー半導体モジュールは、ケース内にパワー半導体チップを有するパワー半導体モジュールにおいて、上記パワー半導体チップと主回路配線の電極とを導電性樹脂で電気的に接続するとともに、上記主回路配線の電極を平板電極で構成し、かつ上記主回路配線の電極の、上記パワー半導体チップ側の、上記パワー半導体チップの中央部分に対向する面上に凹部を設け、上記パワー半導体チップを流れる電流が上記パワー半導体チップの中央部分を避けて周辺部分に流れる構造としたものである。
【００１４】
また、本発明のパワー半導体モジュールは、ケース内にパワー半導体チップを有するパワー半導体モジュールにおいて、上記パワー半導体チップと主回路配線の電極とを導電性樹脂で電気的に接続するとともに、１チップ当たりに複数個の主回路配線の電極を、上記パワー半導体チップの中央部分を避けて接続し、上記パワー半導体チップを流れる電流が上記パワー半導体チップの中央部分を避けて周辺部分に流れる構造としたものである。
【００１５】
また、本発明のパワー半導体モジュールは、ケース内にパワー半導体チップを有するパワー半導体モジュールにおいて、上記パワー半導体チップと主回路配線の電極とを導電性樹脂で電気的に接続するとともに、上記主回路配線の電極を平板電極で構成し、かつ上記導電性樹脂を、上記パワー半導体チップの中央部分を避けて塗布し、上記パワー半導体チップを流れる電流が上記パワー半導体チップの中央部分を避けて周辺部分に流れる構造としたものである。
【００１６】
また、本発明のパワー半導体モジュールは、ケース内にパワー半導体チップを有するパワー半導体モジュールにおいて、上記パワー半導体チップと主回路配線の電極とを導電性樹脂で電気的に接続するとともに、上記主回路配線の電極を平板電極で構成し、かつ上記パワー半導体チップの中央部分と上記主回路配線の電極の中央部分との間に絶縁性の部材を介在させて、上記パワー半導体チップを流れる電流が上記パワー半導体チップの中央部分を避けて周辺部分に流れる構造としたものである。
【００１７】
また、本発明のパワー半導体モジュールは、上記いずれかの構成において、導電性樹脂で接合される主回路配線の電極を加圧する加圧装置を備えたものである。
【００１８】
【発明の実施の形態】
実施の形態１．
以下、本発明の実施の形態１を図を用いて説明する。以下ではパワー半導体チップとしてＩＧＢＴを用いたパワー半導体モジュールについて説明する。図１（ａ）は、本発明の実施の形態１によるパワー半導体モジュールの主要部を示す断面構成図であり、半導体チップと主回路配線との電気的接続部分を示している。図１（ｂ）は、図１（ａ）の上面図であり、パワー半導体チップと導電性樹脂と主回路配線の電極部分を示している。
図１において、１はアルミニウム（Ａｌ）や銅（Ｃｕ）等の放熱用ベース板、２は両面にＣｕ等の金属の薄板が接着された窒化アルミ（ＡｌＮ）等の絶縁基板であり、放熱用ベース板１上にはんだ等により固定される。絶縁基板２上にはＩＧＢＴ等のパワー半導体チップ３が搭載されている。ＩＧＢＴ３は上面がエミッタ電極４、下面がコレクタ電極５となっており、コレクタ電極５ははんだ等の導電性材料により絶縁基板２上の金属薄板と電気的に接続される。この場合、ＩＧＢＴ３と絶縁基板２との線膨張係数差は小さいので、はんだのように硬い材料であっても、熱ストレスによるクラックは生じにくい。１３は主回路配線のエミッタ側電極であり、平板電極で構成されており、ＩＧＢＴ３のエミッタ電極４に接触するように配置される。また、平板電極で構成された主回路配線の電極１３には、パワー半導体チップ３の中央部分に対向する位置に貫通孔１３ａが設けられている。１２はＩＧＢＴ３のエミッタ電極４と主回路配線電極１３とを接続する導電性樹脂である。
【００１９】
ここで、パワー半導体チップの電気的接続に導電性樹脂を用いる理由について説明する。従来のように、パワー半導体モジュールにおいて、ＩＧＢＴ等の半導体チップとＡｌワイヤボンドとをはんだ付け等によって電気的に接続する場合、例えば、パワー半導体チップの線膨張係数が３〜４ｐｐｍ／℃であるのに対し、Ａｌワイヤの線膨張係数は２４ｐｐｍ／℃であって、熱膨張差が非常に大きく、運転時に生じる急激な温度サイクルによって、急激で高頻度な熱ストレスが発生し、接続部の剥離等の問題が生じ易く、電気的接続部の長期信頼性に問題があった。導電性樹脂は、はんだ等の他の接合用導電性材料に比べて弾性率が低く、熱ストレス緩衝用材料として使用されている。しかし、導電性樹脂は金属に比べれば体積抵抗率が非常に大きく、大電流を扱う用途には使用できないというのが、一般的な認識となっている。例えば配電系統への導電性樹脂の導入は、導電性樹脂部でのジュール損失が致命的な欠陥であり、現実的ではなかった。
しかし、半導体による電力変換装置では、パワー半導体自身の通電時のＯＮ電圧が数Ｖと大きく、非常に大きな発熱を生じる。したがってパワー半導体モジュール内の電気的接続部としては、他の重電分野におけるような、低抵抗、低損失は必ずしも必要でなく、パワー半導体チップのＯＮ電圧、発生損失（ジュール損失）に比べて十分無視できる程度であればよい。
【００２０】
以上を整理すると、パワー半導体モジュールにおける電気的接続部として、満たすべき最も重要な条件として次の２つがある。
（１） モータ駆動電流のような大電流を通電する能力を有し、かつ通電時での電気的接続部における発生電圧および発生損失が、パワー半導体チップにおける発生電圧および発生損失に比べ十分小さいこと。
（２） パワー半導体チップの発熱に起因する、急峻で高頻度な熱ストレスに対して、上記（１）の条件を長期にわたって満足すること。
【００２１】
パワー半導体モジュールでは、数十Ａ／ｃｍ2以上の電流を定常的に通電する必要が生じる場合があるが、導電性樹脂をこのような大電流通電部に適用した例はこれまでない。そこで発明者らは、パワー半導体モジュールにおける電気的接続部への導電性樹脂の適用の可能性を検討するため、大電流通電試験およびパワーサイクル試験等のヒートショックサイクル試験を実施し、導電性樹脂がパワー半導体モジュールの電気的接続に十分適用できることを見出した。本発明は、これら数多くの実験結果より得られた知見のもとになされたものである。
【００２２】
また、実施の形態１では、図１に示すように、パワー半導体チップ３と接続される平板状の主回路配線電極１３は、パワー半導体チップの中央部分に対向する位置に貫通孔１３ａが設けられた構造となっていることを特徴としている。このような構造にすることにより、電流がパワー半導体チップ３の中央部分を流れることができず、周辺部分を流れることになる。パワー半導体チップ３に電流が均一に流れる場合、パワー半導体チップ３の中央部分の温度が最も高くなる。そのため実機の運転時においては、チップの中央部分が最も高温に上がるが、冷却時にはチップ全体が均一な温度まで低下する。したがって、パワー半導体チップ３の中央部分が最も温度差がつくことになり、熱ストレスによる不良が最も発生しやすい。本実施の形態においては、主回路配線電極１３の中央部に貫通孔１３ａを設けることによって、パワー半導体チップ３の中央部分が主回路配線電極１３と接触しないようにし、チップ３の中央部分に電流を流さないようにしているので、チップ３の中央部分の発熱が抑えられる。その結果、従来見られたような、チップの中央部分への熱ストレスの集中により生じる接続部分の不良が抑えられ、さらに電気的接続の信頼性が向上する。
【００２３】
なお、ここで用いられる導電性樹脂１２としては、体積抵抗率が１Ω・ｃｍ以下のものが好ましい。これは、例えば、体積抵抗率１０Ω・ｃｍ程度のものでは、樹脂部で発生する抵抗により、パワー半導体チップの動作に悪影響を及ぼすことがあるためである。また、導電性樹脂部１２で発生する熱が大きくなることにより、ヒートシンク、絶縁基板等、モジュール内部を含めた他の構造を変更しなければならない問題がでてくる。
【００２４】
また、ここで用いられる導電性樹脂１２の弾性率は、３０００ｋｇｆ／ｍｍ2以下であることが好ましい。例えば、弾性率５０００ｋｇｆ／ｍｍ2の導電性樹脂を用いた場合、樹脂の靱性が低いため、パワー半導体チップ３と電極１３の熱膨張差による熱ストレスを吸収できなくなる場合がある。
【００２５】
さらに、ここで用いられる導電性樹脂１２のマトリクス材料としては、エポキシ樹脂が好適に用いられるが、これに限定されず、本実施の形態で述べた体積抵抗率および弾性率を満足する材料であれば、他の材料、例えば、ポリイミド樹脂、フェノール樹脂、シリコーン樹脂なども使用できる。
同様に、充填する導電性フィラーについても、通常は、導電率や安定性等の理由により、銀フィラーが好適に用いられるが、例えば、銅、金、白金、ニッケル、カーボン等のフィラーも、本発明で規定した体積抵抗率と弾性率を満たすものであれば使用できる。
【００２６】
実施の形態２．
また、実施の形態１では、主回路配線電極１３の中央部分に貫通孔を設けたが、主回路配線電極１３のパワー半導体チップ側の面に、パワー半導体チップ３の中央部分に対向して凹部１３ｂを設けてもよい。図２はこのような本発明の実施の形態２によるパワー半導体モジュールの主要部を示す断面構成図であり、半導体チップと主回路配線との電気的接続部分を示している。図２（ｂ）は、図２（ａ）の上面図であり、パワー半導体チップと導電性樹脂と主回路配線の電極部分を示している。
【００２７】
図２のような構成にすることでも、電流は、凹部１３ｂによりチップの中央部分を避けて周辺部分を流れることになるため、接続界面に加わる熱ストレスの最大値を低減でき、電気的接続部の長期信頼性向上に効果がある。
【００２８】
実施の形態３．
図３は本発明の実施の形態３によるパワー半導体モジュールの主要部を示す断面構成図であり、半導体チップと主回路配線との電気的接続部分を示している。図３（ｂ）は、図３（ａ）の上面図であり、パワー半導体チップと導電性樹脂と主回路配線の電極部分を示している。
図３において、パワー半導体チップ３と接続される主回路配線電極１３は、１チップ当たり複数個あり、かつそれらの各電極１３が、パワー半導体チップ３の中央部分を避けてチップに接続されている。このような構造にすることにより、１接続部当たりの熱ストレスを低減でき、接続部が複数あることによる信頼性向上が得られるばかりでなく、最も熱ストレスが集中しやすい中央部分に接続部が無いことから、電気的接続の長期信頼性がさらに向上する効果がある。
【００２９】
実施の形態４．
図４は本発明の実施の形態４によるパワー半導体モジュールの主要部を示す断面構成図であり、半導体チップと主回路配線との電気的接続部分を示している。図４（ｂ）は、図４（ａ）の上面図であり、パワー半導体チップと導電性樹脂と主回路配線の電極部分を示している。
本実施の形態４では、平板状の主回路配線電極１３のパワー半導体チップ側の面は平面でも加工していても構わないが、導電性樹脂１２がパワー半導体チップ３の中央部分を避けて塗布されていることが特徴となっている。この場合でも、電流は中央部分を流れることができないため、通電時の発熱の集中といった現象が抑えられ、電気的接続部の長寿命化に効果がある。
【００３０】
実施の形態５．
図５は本発明の実施の形態５によるパワー半導体モジュールの主要部を示す断面構成図であり、半導体チップと主回路配線との電気的接続部分を示している。図５（ｂ）は、図５（ａ）の上面図であり、パワー半導体チップと導電性樹脂と主回路配線の電極部分を示している。
本実施の形態５では、パワー半導体チップ３の中央部分と主回路配線電極１３の中央部分との間に絶縁性の部材１４を介在させて、パワー半導体チップ３と主回路配線電極１３とを導電性樹脂１２で電気的に接続している。絶縁性の部材１４は通常の絶縁材料であれば特に限定はされないが、パワー半導体チップ３との熱膨張差や耐熱性の観点から、窒化アルミ（ＡｌＮ）、Ａｌ2Ｏ3、Ｓｉ3Ｏ4などのセラミック系の材料が好適に使用される。
【００３１】
実施の形態６．
図６は本発明の実施の形態６によるパワー半導体モジュールの主要部を示す断面構成図であり、半導体チップと主回路配線との電気的接続部分を示している。図６に示すパワー半導体モジュールは、実施の形態２で示したパワー半導体モジュールに電気的接続部を加圧するための加圧装置１５を設けたものである。なお、本実施の形態６は、上述の全ての実施の形態によるパワー半導体モジュールにも適用可能である。
図６において、加圧装置１５には、ばねやゴム、スポンジなどの加圧部材を用いることが適している。本実施の形態では、加圧装置１５は、ケース１０の天井部と、主回路配線電極１３との間に配置されている。なお、加圧部材には、絶縁性の材料、非絶縁性の材料共に使用可能であるが、後者の場合は、加圧部材と電気的接続部とを絶縁する方がより望ましい。
【００３２】
このような構造にすることにより、加圧しない場合よりも、さらにパワー半導体モジュールの電気的性能、長期信頼性を向上することができる。これは、導電性樹脂部が加圧されることにより、樹脂内の導電性粒子同士の接触がよくなり、体積抵抗率が低下し、かつ導電性樹脂とパワー半導体チップ、及び導電性樹脂と配線電極との接触抵抗が低下すること、並びに導電性樹脂とパワー半導体チップ、及び導電性樹脂と配線電極との界面の密着性が高まり、接続信頼性が向上することによる。この効果は導電性樹脂の弾性率が小さいほど効果がある。
【００３３】
なお、上記各実施の形態で説明したパワー半導体チップとしては、ＩＧＢＴの他に、バイポーラトランジスタ、ＭＯＳ−ＦＥＴ、ＩＧＢＴ、ＧＴＯ、サイリスタ、トライアック、ＳＩＴ、ダイオード等のいわゆるパワー半導体と称されるものでもよく、さらにこれらを単独で使用してもよく、また、混在させて使用してもよい。
【００３４】
また、以上では主としてＩＧＢＴ等のパワー半導体チップのエミッタ電極と主回路配線電極との電気的接続について述べたが、これに限定されるものではなく、例えば、コレクタ電極と配線電極との接続、チップとコレクタ電極との接続、主回路配線電極と外部配線との接続、絶縁基板上の配線と電極との接続、ゲート配線などにも適用することもできる。
【００３５】
【発明の効果】
以上のように、本発明のパワー半導体モジュールによれば、ケース内にパワー半導体チップを有するパワー半導体モジュールにおいて、上記パワー半導体チップと主回路配線の電極とを導電性樹脂で電気的に接続するとともに、上記主回路配線の電極を平板電極で構成し、かつ上記主回路配線の電極の、上記パワー半導体チップの中央部分に対向する位置に貫通孔を設け、上記パワー半導体チップを流れる電流が上記パワー半導体チップの中央部分を避けて周辺部分に流れる構造としたので、パワー半導体モジュールの電気的接続部の長期信頼性が向上する効果がある。
【００３７】
また、本発明のパワー半導体モジュールによれば、ケース内にパワー半導体チップを有するパワー半導体モジュールにおいて、上記パワー半導体チップと主回路配線の電極とを導電性樹脂で電気的に接続するとともに、上記主回路配線の電極を平板電極で構成し、かつ上記主回路配線の電極の、上記パワー半導体チップ側の、上記パワー半導体チップの中央部分に対向する面上に凹部を設け、上記パワー半導体チップを流れる電流が上記パワー半導体チップの中央部分を避けて周辺部分に流れる構造としたので、パワー半導体モジュールの電気的接続部の長期信頼性が向上する効果がある。
【００３８】
また、本発明のパワー半導体モジュールによれば、ケース内にパワー半導体チップを有するパワー半導体モジュールにおいて、上記パワー半導体チップと主回路配線の電極とを導電性樹脂で電気的に接続するとともに、１チップ当たりに複数個の主回路配線の電極を、上記パワー半導体チップの中央部分を避けて接続し、上記パワー半導体チップを流れる電流が上記パワー半導体チップの中央部分を避けて周辺部分に流れる構造としたので、パワー半導体モジュールの電気的接続部の長期信頼性が向上する効果がある。
【００３９】
また、本発明のパワー半導体モジュールによれば、ケース内にパワー半導体チップを有するパワー半導体モジュールにおいて、上記パワー半導体チップと主回路配線の電極とを導電性樹脂で電気的に接続するとともに、上記主回路配線の電極を平板電極で構成し、かつ上記導電性樹脂を、上記パワー半導体チップの中央部分を避けて塗布し、上記パワー半導体チップを流れる電流が上記パワー半導体チップの中央部分を避けて周辺部分に流れる構造としたので、パワー半導体モジュールの電気的接続部の長期信頼性が向上する効果がある。
【００４０】
また、本発明のパワー半導体モジュールによれば、ケース内にパワー半導体チップを有するパワー半導体モジュールにおいて、上記パワー半導体チップと主回路配線の電極とを導電性樹脂で電気的に接続するとともに、上記主回路配線の電極を平板電極で構成し、かつ上記パワー半導体チップの中央部分と上記主回路配線の電極の中央部分との間に絶縁性の部材を介在させて、上記パワー半導体チップを流れる電流が上記パワー半導体チップの中央部分を避けて周辺部分に流れる構造としたので、パワー半導体モジュールの電気的接続部の長期信頼性が向上する効果がある。
【００４１】
また、本発明のパワー半導体モジュールによれば、上記いずれかの構成において、導電性樹脂で接合される主回路配線の電極を加圧する加圧装置を備えたので、パワー半導体モジュールの電気的接続部の長期信頼性がさらに向上する効果がある。
【図面の簡単な説明】
【図１】 本発明の実施の形態１によるパワー半導体モジュールの主要部を示す断面構成図及び上面図である。
【図２】 本発明の実施の形態２によるパワー半導体モジュールの主要部を示す断面構成図及び上面図である。
【図３】 本発明の実施の形態３によるパワー半導体モジュールの主要部を示す断面構成図及び上面図である。
【図４】 本発明の実施の形態４によるパワー半導体モジュールの主要部を示す断面構成図及び上面図である。
【図５】 本発明の実施の形態５によるパワー半導体モジュールの主要部を示す断面構成図及び上面図である。
【図６】 本発明の実施の形態６によるパワー半導体モジュールの主要部を示す断面構成図である。
【図７】 従来のパワー半導体モジュールの主要部を示す断面構成図である。
【符号の説明】
１ 放熱用ベース板、２ 絶縁基板、３ パワー半導体チップ、４ エミッタ電極、５ コレクタ電極、６ エミッタ用ブスバー、７ コレクタ用ブスバー、８ 中継基板、９ Ａｌワイヤボンド、１０ ケース、１１ シリコンゲル、１２ 導電性樹脂、１３ 主回路配線電極、１３ａ 貫通孔、１３ｂ 凹部、１４絶縁性の部材、１５ 加圧装置。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a power semiconductor module used in a power conversion device that controls a drive current of an electric device such as a motor, and more particularly to a structure of an electrical connection portion between a power semiconductor chip and a main circuit wiring in the power semiconductor module. Is.
[0002]
[Prior art]
FIG. 7 is a schematic cross-sectional view of the main part of a general-purpose IGBT (Insulated Gate Bipolar Transistor) module as an example of a conventional power semiconductor module. In the figure, 1 is a heat radiating base plate made of aluminum (Al), copper (Cu) or the like, 2 is an insulating substrate made of alumina, aluminum nitride (AlN) or the like with a thin metal plate such as Cu bonded to both sides. Yes, it is fixed on the base plate for heat dissipation with solder or the like. A power semiconductor chip 3 such as an IGBT is mounted on the insulating substrate 2. The IGBT 3 has an emitter electrode 4 on the upper surface and a collector electrode 5 on the lower surface, and the collector electrode 5 is electrically connected to a metal thin plate on the insulating substrate 2 by a conductive material such as solder. Reference numerals 6 and 7 denote bus bars for an emitter and a collector, respectively, which constitute the main part of the main circuit wiring. Each bus bar 6, 7 is electrically connected to the relay substrate 8 and is also electrically connected to external wiring outside the case. Similar to the insulating substrate, the relay substrate 8 is an insulating substrate in which a thin plate of metal such as Cu is bonded on both sides, and is fixed on the heat radiating base plate 1 with solder or the like. The power semiconductor chip 3 and the relay substrate 8 are electrically connected by an aluminum (Al) wire bond 9. Reference numeral 10 denotes a case of a power semiconductor module, and the module inside the case is molded with silicon gel 11.
[0003]
As described above, the conventional power semiconductor module uses an Al wire bond for electrical connection between the power semiconductor chip and the bus bar.
On the other hand, as another electrical connection method of the power semiconductor module, there is a connection method by a pressure contact method in which a contact surface of a conductor to be connected is pressurized by a pressure from the outside of the module, which is employed particularly for large capacity.
As described above, in the conventional power semiconductor module, either the wire bond or the pressure contact method is adopted as an electrical connection method between the power semiconductor chip and the main circuit wiring.
[0004]
[Problems to be solved by the invention]
In a conventional power semiconductor module, when an Al wire bond is used for the electrical connection between the power semiconductor chip and the main circuit wiring, a module having a small capacity of 5 A or less has a small amount of heat generated during operation, and therefore the wire bond connection portion. However, if a module with a larger capacity is used, the amount of heat generated during operation is large and the temperature cycle is severe, so the thermal stress caused by the difference in thermal expansion between the power semiconductor chip and Al in the Al wire bond part. As a result, there is a problem that the bonding surface of the Al wire bond portion is easily peeled off and lacks long-term reliability.
[0005]
More specifically, the stress mode described here is greatly different in stress mode from that using a normal semiconductor chip. In a normal semiconductor chip, the amount of heat generated by the chip itself is small, and the main heat stress is due to external factors such as solder reflow in the assembly process and heat shock cycle during the reliability evaluation test. A major problem in power semiconductor modules lies in thermal stress caused by frequent occurrence of steep temperature cycles due to large heat generation of the power semiconductor chip itself during operation (when a large current is applied). This becomes a serious problem as the capacity of the module becomes larger. In addition, a large-capacity module used in the electric railway and steel fields requires a long life of 20 to 30 years in such a severe usage environment.
Therefore, in power semiconductor modules, the so-called “power cycle test” is called a “power cycle test”, and the power semiconductor chip is intermittently supplied with a large current to change the temperature very quickly, and this is repeated very many times. It is required to clear the heat shock cycle test to be performed.
This is also described in the literature (title: RELIABILITY TESTING ANDANALYSIS OF IGBT POWER MODULES), author: Peter Yacob, Marcel Held, Paulo Scacco, Wuchen Wu, source: IEE ColloBulT25. However, in the conventional power semiconductor module, in the power cycle test, under the condition of ΔTj = 70 ° C., most of them were broken in the bonding surface peeling mode of the wire bond connection portion at 80,000 times to 200,000 times. Here, ΔTj is the temperature change of the chip during one cycle.
[0006]
On the other hand, as a problem other than the thermal stress, in the power semiconductor module, in the method in which the chip and the electrode of the main circuit wiring are joined by wire bonding, the cross-sectional area of the wire is small and the number of wires that can be bonded is limited. . For this reason, the electrode (emitter electrode) formed on the chip surface cannot be used effectively, the current shunting characteristics are deteriorated, or in a large capacity module, the current density flowing through the wire becomes very high, which is caused by overcurrent. The risk of disconnection increases.
[0007]
Furthermore, in the power semiconductor module manufacturing process, in order to increase the bonding strength of the wire, there is a tendency to increase the pressure applied to the bonding surface at the time of wire bonding. In the case where an insulating film between the gate and the emitter is formed below the emitter electrode surface, the gate-emitter insulation failure, the chip is easily broken, and the yield is lowered.
[0008]
On the other hand, in the electrical connection method using the pressure welding method that has been conventionally used in large-capacity power semiconductor modules, fluctuations in the applied pressure have a significant effect on the electrical characteristics of the module, and there is a problem in maintainability. A power conversion device such as an inverter using a pressure-contact type power semiconductor module has a problem that it becomes a large-scale device such as a stack structure.
[0009]
As described above, in a power semiconductor module, the coefficient of linear expansion differs greatly from that of a power semiconductor chip and a metal such as copper or aluminum under repeated rapid and frequent temperature changes due to the heat generated by the power semiconductor chip itself. It is necessary to secure an electrical connection that can stably supply a large current over a long period of time to the connection part with the material being used. As the power semiconductor chips are becoming more and more heated, the heat generation density of the power semiconductor chips has become extremely high, and ensuring the long-term reliability of electrical connection is the most important issue for power semiconductor modules.
[0010]
The present invention has been made to solve the various problems as described above, and in particular, has an object to obtain long-term reliability of electrical connection which is strongly required for a power semiconductor module.
[0011]
[Means for Solving the Problems]
The present invention The pa In the power semiconductor module having the power semiconductor chip in the case, the power semiconductor module electrically connects the power semiconductor chip and the electrode of the main circuit wiring with a conductive resin, The electrode of the main circuit wiring is constituted by a flat plate electrode, and a through hole is provided at a position of the electrode of the main circuit wiring facing the central portion of the power semiconductor chip, The current flowing through the power semiconductor chip avoids the central portion of the power semiconductor chip. Around It has a structure that flows to the side part.
[0013]
In addition, the present invention The pa The semiconductor module In a power semiconductor module having a power semiconductor chip in a case, the power semiconductor chip and the electrode of the main circuit wiring are electrically connected with a conductive resin, and the above Main circuit wiring electrodes The Consists of flat electrodes And the electrodes of the main circuit wiring On the power semiconductor chip side, the above A recess is formed on the surface facing the center of the power semiconductor chip. And a structure in which the current flowing through the power semiconductor chip flows to the peripheral portion avoiding the central portion of the power semiconductor chip. Is.
[0014]
In addition, the present invention The pa The semiconductor module In the power semiconductor module having the power semiconductor chip in the case, the power semiconductor chip and the electrode of the main circuit wiring are electrically connected with a conductive resin, Per chip Multiple Main circuit wiring electrodes The above Avoid the center of the power semiconductor chip Connected, and the current flowing through the power semiconductor chip is structured to flow to the peripheral portion avoiding the central portion of the power semiconductor chip. Is.
[0015]
In addition, the present invention The pa The semiconductor module In a power semiconductor module having a power semiconductor chip in a case, the power semiconductor chip and the electrode of the main circuit wiring are electrically connected with a conductive resin, and the above Main circuit wiring electrodes The Consists of flat electrodes And above Conductive resin The Apply away from the center of the power semiconductor chip The current flowing through the power semiconductor chip flows to the peripheral portion avoiding the central portion of the power semiconductor chip. Is.
[0016]
In addition, the present invention The pa The semiconductor module In a power semiconductor module having a power semiconductor chip in a case, the power semiconductor chip and the electrode of the main circuit wiring are electrically connected with a conductive resin, and the above Main circuit wiring electrodes The Consists of flat electrodes And above The central part of the power semiconductor chip and the above An insulating member is interposed between the central part of the main circuit wiring electrodes, The structure is such that the current flowing through the power semiconductor chip flows to the peripheral portion avoiding the central portion of the power semiconductor chip. Is.
[0017]
In addition, the present invention The pa The semiconductor module the above In any configuration, a pressurizing device that pressurizes the electrodes of the main circuit wiring joined by the conductive resin is provided.
[0018]
DETAILED DESCRIPTION OF THE INVENTION
Embodiment 1 FIG.
Embodiment 1 of the present invention will be described below with reference to the drawings. Hereinafter, a power semiconductor module using an IGBT as a power semiconductor chip will be described. FIG. 1A is a cross-sectional configuration diagram showing a main part of the power semiconductor module according to the first embodiment of the present invention, and shows an electrical connection portion between the semiconductor chip and the main circuit wiring. FIG. 1B is a top view of FIG. 1A and shows a power semiconductor chip, conductive resin, and electrode portions of main circuit wiring.
In FIG. 1, 1 is a heat dissipation base plate such as aluminum (Al) or copper (Cu), 2 is an insulating substrate such as aluminum nitride (AlN) with a thin metal plate such as Cu bonded on both sides, and is used for heat dissipation. It is fixed on the base plate 1 with solder or the like. A power semiconductor chip 3 such as an IGBT is mounted on the insulating substrate 2. The IGBT 3 has an emitter electrode 4 on the upper surface and a collector electrode 5 on the lower surface, and the collector electrode 5 is electrically connected to a metal thin plate on the insulating substrate 2 by a conductive material such as solder. In this case, since the linear expansion coefficient difference between the IGBT 3 and the insulating substrate 2 is small, even a hard material such as solder hardly causes cracks due to thermal stress. Reference numeral 13 denotes an emitter-side electrode of the main circuit wiring, which is composed of a flat plate electrode and is arranged so as to be in contact with the emitter electrode 4 of the IGBT 3. In addition, a through-hole 13 a is provided in a position facing the central portion of the power semiconductor chip 3 in the electrode 13 of the main circuit wiring constituted by a flat plate electrode. A conductive resin 12 connects the emitter electrode 4 of the IGBT 3 and the main circuit wiring electrode 13.
[0019]
Here, the reason why the conductive resin is used for electrical connection of the power semiconductor chip will be described. In a power semiconductor module, when a semiconductor chip such as an IGBT and an Al wire bond are electrically connected by soldering or the like, for example, the power semiconductor chip has a linear expansion coefficient of 3 to 4 ppm / ° C. On the other hand, the linear expansion coefficient of the Al wire is 24 ppm / ° C., and the thermal expansion difference is very large. Due to the rapid temperature cycle that occurs during operation, rapid and frequent thermal stress occurs, peeling of the connection portion, etc. There is a problem in the long-term reliability of the electrical connection portion. The conductive resin has a lower elastic modulus than other conductive materials for bonding such as solder, and is used as a heat stress buffer material. However, it is generally recognized that conductive resins have a very large volume resistivity compared to metals and cannot be used for applications that handle large currents. For example, the introduction of the conductive resin into the power distribution system is not realistic because the Joule loss in the conductive resin portion is a fatal defect.
However, in a power converter using a semiconductor, the ON voltage when the power semiconductor itself is energized is as large as several volts, and a very large amount of heat is generated. Therefore, the electrical connection in the power semiconductor module does not necessarily require low resistance and low loss as in other heavy electric fields, and is sufficient compared to the ON voltage and generated loss (joule loss) of the power semiconductor chip. It only needs to be negligible.
[0020]
To summarize the above, there are the following two most important conditions to be satisfied as the electrical connection portion in the power semiconductor module.
(1) It has the ability to pass a large current such as a motor drive current, and the generated voltage and generated loss at the electrical connection portion when energized are sufficiently smaller than the generated voltage and generated loss in the power semiconductor chip. .
(2) The condition (1) should be satisfied over a long period of time against a sharp and frequent thermal stress caused by the heat generated by the power semiconductor chip.
[0021]
For power semiconductor modules, dozens of A / cm 2 Although it may be necessary to constantly energize the above current, there has been no example in which a conductive resin is applied to such a large current energizing part. Therefore, the inventors conducted heat shock cycle tests such as a large current conduction test and a power cycle test in order to examine the possibility of applying the conductive resin to the electrical connection portion in the power semiconductor module, and the conductive resin Has been found to be sufficiently applicable to electrical connection of power semiconductor modules. The present invention has been made based on the knowledge obtained from these many experimental results.
[0022]
In the first embodiment, as shown in FIG. 1, the flat main circuit wiring electrode 13 connected to the power semiconductor chip 3 is provided with a through hole 13a at a position facing the central portion of the power semiconductor chip. It is characterized by the structure. With this structure, current cannot flow through the central portion of the power semiconductor chip 3 but flows through the peripheral portion. When current flows uniformly through the power semiconductor chip 3, the temperature of the central portion of the power semiconductor chip 3 is highest. For this reason, during operation of the actual machine, the central portion of the chip rises to the highest temperature, but the entire chip falls to a uniform temperature during cooling. Therefore, the central portion of the power semiconductor chip 3 has the highest temperature difference, and a defect due to thermal stress is most likely to occur. In the present embodiment, by providing a through hole 13 a in the central portion of the main circuit wiring electrode 13, the central portion of the power semiconductor chip 3 is prevented from coming into contact with the main circuit wiring electrode 13. Therefore, the heat generation at the center portion of the chip 3 can be suppressed. As a result, it is possible to suppress defects in the connection portion caused by concentration of thermal stress on the center portion of the chip as seen in the past, and further improve the reliability of electrical connection.
[0023]
In addition, as the conductive resin 12 used here, a resin having a volume resistivity of 1 Ω · cm or less is preferable. This is because, for example, when the volume resistivity is about 10 Ω · cm, the resistance generated in the resin portion may adversely affect the operation of the power semiconductor chip. Further, since the heat generated in the conductive resin portion 12 becomes large, there arises a problem that other structures including the inside of the module, such as a heat sink and an insulating substrate, must be changed.
[0024]
The elastic modulus of the conductive resin 12 used here is 3000 kgf / mm. 2 The following is preferable. For example, elastic modulus 5000 kgf / mm 2 When the conductive resin is used, since the toughness of the resin is low, it may be impossible to absorb the thermal stress due to the difference in thermal expansion between the power semiconductor chip 3 and the electrode 13.
[0025]
Further, as the matrix material of the conductive resin 12 used here, an epoxy resin is preferably used, but is not limited to this, and any material satisfying the volume resistivity and elastic modulus described in this embodiment. For example, other materials such as polyimide resin, phenol resin, and silicone resin can be used.
Similarly, as for the conductive filler to be filled, usually, a silver filler is suitably used for reasons such as conductivity and stability. For example, fillers such as copper, gold, platinum, nickel, and carbon are also used. Any material satisfying the volume resistivity and elastic modulus defined in the invention can be used.
[0026]
Embodiment 2. FIG.
In the first embodiment, the through hole is provided in the central portion of the main circuit wiring electrode 13, but the concave portion is formed on the surface of the main circuit wiring electrode 13 on the power semiconductor chip side so as to face the central portion of the power semiconductor chip 3. 13b may be provided. FIG. 2 is a cross-sectional view showing the main part of the power semiconductor module according to the second embodiment of the present invention, and shows an electrical connection portion between the semiconductor chip and the main circuit wiring. FIG. 2B is a top view of FIG. 2A and shows a power semiconductor chip, a conductive resin, and electrode portions of the main circuit wiring.
[0027]
Even in the configuration as shown in FIG. 2, since the current flows through the peripheral portion by avoiding the central portion of the chip by the recess 13b, the maximum value of the thermal stress applied to the connection interface can be reduced, and the electrical connection portion It is effective in improving long-term reliability.
[0028]
Embodiment 3 FIG.
FIG. 3 is a cross-sectional configuration diagram showing the main part of the power semiconductor module according to Embodiment 3 of the present invention, and shows the electrical connection between the semiconductor chip and the main circuit wiring. FIG. 3B is a top view of FIG. 3A and shows the power semiconductor chip, conductive resin, and electrode portions of the main circuit wiring.
In FIG. 3, there are a plurality of main circuit wiring electrodes 13 connected to the power semiconductor chip 3 per chip, and each of these electrodes 13 is connected to the chip avoiding the central portion of the power semiconductor chip 3. . With such a structure, the thermal stress per connection part can be reduced, and not only the improvement in reliability due to the plurality of connection parts can be obtained, but also the connection part is provided in the central part where heat stress is most likely to concentrate. Since there is not, there exists an effect which further improves the long-term reliability of electrical connection.
[0029]
Embodiment 4 FIG.
FIG. 4 is a cross-sectional configuration diagram showing the main part of the power semiconductor module according to the fourth embodiment of the present invention, and shows the electrical connection between the semiconductor chip and the main circuit wiring. FIG. 4B is a top view of FIG. 4A and shows the power semiconductor chip, conductive resin, and electrode portions of the main circuit wiring.
In the fourth embodiment, the surface of the flat main circuit wiring electrode 13 on the side of the power semiconductor chip may be flat or processed, but the conductive resin 12 is applied while avoiding the central portion of the power semiconductor chip 3. It is characterized by being. Even in this case, since the current cannot flow through the central portion, a phenomenon such as concentration of heat generation during energization can be suppressed, which is effective in extending the life of the electrical connection portion.
[0030]
Embodiment 5. FIG.
FIG. 5 is a cross-sectional configuration diagram showing a main part of a power semiconductor module according to Embodiment 5 of the present invention, and shows an electrical connection portion between the semiconductor chip and the main circuit wiring. FIG. 5B is a top view of FIG. 5A and shows the power semiconductor chip, conductive resin, and electrode portions of the main circuit wiring.
In the fifth embodiment, an insulating member 14 is interposed between the central portion of the power semiconductor chip 3 and the central portion of the main circuit wiring electrode 13 to conduct the power semiconductor chip 3 and the main circuit wiring electrode 13. The resin 12 is electrically connected. The insulating member 14 is not particularly limited as long as it is a normal insulating material, but from the viewpoint of thermal expansion difference from the power semiconductor chip 3 and heat resistance, aluminum nitride (AlN), Al 2 O Three , Si Three O Four A ceramic material such as is preferably used.
[0031]
Embodiment 6 FIG.
FIG. 6 is a cross-sectional configuration diagram showing a main part of a power semiconductor module according to Embodiment 6 of the present invention, and shows an electrical connection portion between the semiconductor chip and the main circuit wiring. The power semiconductor module shown in FIG. 6 is obtained by providing the power semiconductor module shown in Embodiment 2 with a pressurizing device 15 for pressurizing the electrical connection portion. The sixth embodiment can also be applied to the power semiconductor modules according to all the above-described embodiments.
In FIG. 6, it is suitable to use a pressure member such as a spring, rubber, or sponge for the pressure device 15. In the present embodiment, the pressure device 15 is disposed between the ceiling portion of the case 10 and the main circuit wiring electrode 13. In addition, although an insulating material and a non-insulating material can be used for the pressurizing member, in the latter case, it is more desirable to insulate the pressurizing member from the electrical connection portion.
[0032]
By adopting such a structure, the electrical performance and long-term reliability of the power semiconductor module can be further improved as compared with the case where no pressure is applied. This is because when the conductive resin portion is pressurized, the contact between the conductive particles in the resin is improved, the volume resistivity is reduced, and the conductive resin and power semiconductor chip, and the conductive resin and wiring are reduced. This is because the contact resistance with the electrode is lowered, and the adhesiveness at the interface between the conductive resin and the power semiconductor chip, and between the conductive resin and the wiring electrode is increased, and the connection reliability is improved. This effect is more effective as the elastic modulus of the conductive resin is smaller.
[0033]
In addition to the IGBT, the power semiconductor chip described in each of the above embodiments may be a so-called power semiconductor such as a bipolar transistor, MOS-FET, IGBT, GTO, thyristor, triac, SIT, or diode. In addition, these may be used alone or in combination.
[0034]
Further, the electrical connection between the emitter electrode of the power semiconductor chip such as IGBT and the main circuit wiring electrode has been described above. However, the present invention is not limited to this. For example, the connection between the collector electrode and the wiring electrode, the chip The present invention can also be applied to the connection between the collector electrode and the collector electrode, the connection between the main circuit wiring electrode and the external wiring, the connection between the wiring on the insulating substrate and the electrode, and the gate wiring.
[0035]
【The invention's effect】
As described above, the present invention The pa According to the word semiconductor module, in the power semiconductor module having the power semiconductor chip in the case, the power semiconductor chip and the electrode of the main circuit wiring are electrically connected with the conductive resin, The electrode of the main circuit wiring is constituted by a flat plate electrode, and a through hole is provided at a position of the electrode of the main circuit wiring facing the central portion of the power semiconductor chip, The current flowing through the power semiconductor chip avoids the central portion of the power semiconductor chip. Around Since the structure flows in the side portion, the long-term reliability of the electrical connection portion of the power semiconductor module is improved.
[0037]
In addition, the present invention The pa According to Wah Semiconductor Module In a power semiconductor module having a power semiconductor chip in a case, the power semiconductor chip and the electrode of the main circuit wiring are electrically connected with a conductive resin, and the above Main circuit wiring electrodes The Consists of flat electrodes And the electrodes of the main circuit wiring On the power semiconductor chip side, the above A recess is formed on the surface facing the center of the power semiconductor chip. Provided above The current flowing through the power semiconductor chip the above Avoid the center of the power semiconductor chip Around Flows to the side Because it was structured There is an effect that the long-term reliability of the electrical connection portion of the power semiconductor module is improved.
[0038]
In addition, the present invention The pa According to Wah Semiconductor Module In the power semiconductor module having the power semiconductor chip in the case, the power semiconductor chip and the electrode of the main circuit wiring are electrically connected with a conductive resin, Per chip Multiple Main circuit wiring electrodes The above Avoid the center of the power semiconductor chip Connect and above The current flowing through the power semiconductor chip the above Avoid the center of the power semiconductor chip Around Flows to the side Because it was structured There is an effect that the long-term reliability of the electrical connection portion of the power semiconductor module is improved.
[0039]
In addition, the present invention The pa According to Wah Semiconductor Module In a power semiconductor module having a power semiconductor chip in a case, the power semiconductor chip and the electrode of the main circuit wiring are electrically connected with a conductive resin, and the above Main circuit wiring electrodes The Consists of flat electrodes And above Conductive resin The Apply away from the center of the power semiconductor chip And above The current flowing through the power semiconductor chip the above Avoid the center of the power semiconductor chip Around Flowing to the side Because it was structured There is an effect that the long-term reliability of the electrical connection portion of the power semiconductor module is improved.
[0040]
In addition, the present invention The pa According to Wah Semiconductor Module In a power semiconductor module having a power semiconductor chip in a case, the power semiconductor chip and the electrode of the main circuit wiring are electrically connected with a conductive resin, and the above Main circuit wiring electrodes The Consists of flat electrodes And above The central part of the power semiconductor chip and the above An insulating member is interposed between the central part of the main circuit wiring electrodes, the above The current flowing through the power semiconductor chip the above Avoid the center of the power semiconductor chip Around Flowing to the side Because it was structured There is an effect that the long-term reliability of the electrical connection portion of the power semiconductor module is improved.
[0041]
In addition, the present invention The pa According to Wah Semiconductor Module the above In any configuration, since the pressurizing device that pressurizes the electrode of the main circuit wiring joined by the conductive resin is provided, there is an effect that the long-term reliability of the electrical connection portion of the power semiconductor module is further improved.
[Brief description of the drawings]
FIGS. 1A and 1B are a cross-sectional configuration diagram and a top view showing main parts of a power semiconductor module according to a first embodiment of the present invention.
FIGS. 2A and 2B are a cross-sectional configuration diagram and a top view showing main parts of a power semiconductor module according to a second embodiment of the present invention. FIGS.
FIGS. 3A and 3B are a cross-sectional configuration diagram and a top view showing main parts of a power semiconductor module according to a third embodiment of the present invention. FIGS.
FIGS. 4A and 4B are a cross-sectional configuration diagram and a top view showing main parts of a power semiconductor module according to a fourth embodiment of the present invention. FIGS.
FIGS. 5A and 5B are a cross-sectional configuration diagram and a top view showing main parts of a power semiconductor module according to a fifth embodiment of the present invention. FIGS.
FIG. 6 is a cross-sectional configuration diagram showing a main part of a power semiconductor module according to a sixth embodiment of the present invention.
FIG. 7 is a cross-sectional configuration diagram showing a main part of a conventional power semiconductor module.
[Explanation of symbols]
1 Base plate for heat dissipation, 2 Insulating substrate, 3 Power semiconductor chip, 4 Emitter electrode, 5 Collector electrode, 6 Bus bar for emitter, 7 Bus bar for collector, 8 Relay substrate, 9 Al wire bond, 10 Case, 11 Silicon gel, 12 Conductive resin, 13 main circuit wiring electrode, 13a through hole, 13b recess, 14 insulating member, 15 pressurizing device.

Claims (6)

ケース内にパワー半導体チップを有するパワー半導体モジュールにおいて、上記パワー半導体チップと主回路配線の電極とを導電性樹脂で電気的に接続するとともに、上記主回路配線の電極を平板電極で構成し、かつ上記主回路配線の電極の、上記パワー半導体チップの中央部分に対向する位置に貫通孔を設け、上記パワー半導体チップを流れる電流が上記パワー半導体チップの中央部分を避けて周辺部分に流れる構造としたことを特徴とするパワー半導体モジュール。 In a power semiconductor module having a power semiconductor chip in a case, the power semiconductor chip and an electrode of the main circuit wiring are electrically connected with a conductive resin, and the electrode of the main circuit wiring is constituted by a plate electrode , and A through hole is provided at a position of the electrode of the main circuit wiring facing the central portion of the power semiconductor chip, and a current flowing through the power semiconductor chip flows to a peripheral portion avoiding the central portion of the power semiconductor chip. features and to Rupa Wah semiconductor module that. ケース内にパワー半導体チップを有するパワー半導体モジュールにおいて、上記パワー半導体チップと主回路配線の電極とを導電性樹脂で電気的に接続するとともに、上記主回路配線の電極を平板電極で構成し、かつ上記主回路配線の電極の、上記パワー半導体チップ側の、上記パワー半導体チップの中央部分に対向する面上に凹部を設け、上記パワー半導体チップを流れる電流が上記パワー半導体チップの中央部分を避けて周辺部分に流れる構造としたことを特徴とするパワー半導体モジュール。 In a power semiconductor module having a power semiconductor chip in a case, the power semiconductor chip and an electrode of the main circuit wiring are electrically connected with a conductive resin, and the electrode of the main circuit wiring is constituted by a plate electrode , and the electrodes of the main circuit lines, said power semiconductor chip side, a concave portion is provided on a surface facing the central portion of the power semiconductor chip, a current flowing through said power semiconductor chip is to avoid the central portion of the power semiconductor chip features and to Rupa Wah semiconductor module that has a structure that flows in the peripheral portion. ケース内にパワー半導体チップを有するパワー半導体モジュールにおいて、上記パワー半導体チップと主回路配線の電極とを導電性樹脂で電気的に接続するとともに、１チップ当たりに複数個の主回路配線の電極を、上記パワー半導体チップの中央部分を避けて接続し、上記パワー半導体チップを流れる電流が上記パワー半導体チップの中央部分を避けて周辺部分に流れる構造としたことを特徴とするパワー半導体モジュール。 In a power semiconductor module having a power semiconductor chip in a case, the power semiconductor chip and the main circuit wiring electrode are electrically connected with a conductive resin, and a plurality of main circuit wiring electrodes are provided per chip . It said power semiconductor chips avoiding the central portion is connected, wherein the to Rupa Wah semiconductor module that current flowing through said power semiconductor chip has a structure that flows in the peripheral portion while avoiding the central portion of the power semiconductor chip. ケース内にパワー半導体チップを有するパワー半導体モジュールにおいて、上記パワー半導体チップと主回路配線の電極とを導電性樹脂で電気的に接続するとともに、上記主回路配線の電極を平板電極で構成し、かつ上記導電性樹脂を、上記パワー半導体チップの中央部分を避けて塗布し、上記パワー半導体チップを流れる電流が上記パワー半導体チップの中央部分を避けて周辺部分に流れる構造としたことを特徴とするパワー半導体モジュール。 In a power semiconductor module having a power semiconductor chip in a case, the power semiconductor chip and an electrode of the main circuit wiring are electrically connected with a conductive resin, and the electrode of the main circuit wiring is constituted by a plate electrode , and the conductive resin, is coated to avoid the central portion of the power semiconductor chip, a current flowing through said power semiconductor chip you characterized in that the structure flowing to the peripheral portion while avoiding the central portion of the power semiconductor chip power semiconductor module. ケース内にパワー半導体チップを有するパワー半導体モジュールにおいて、上記パワー半導体チップと主回路配線の電極とを導電性樹脂で電気的に接続するとともに、上記主回路配線の電極を平板電極で構成し、かつ上記パワー半導体チップの中央部分と上記主回路配線の電極の中央部分との間に絶縁性の部材を介在させて、上記パワー半導体チップを流れる電流が上記パワー半導体チップの中央部分を避けて周辺部分に流れる構造としたことを特徴とするパワー半導体モジュール。 In a power semiconductor module having a power semiconductor chip in a case, the power semiconductor chip and an electrode of the main circuit wiring are electrically connected with a conductive resin, and the electrode of the main circuit wiring is constituted by a plate electrode , and peripheral portion by interposing an insulating member, a current flowing through said power semiconductor chip is to avoid the central portion of the power semiconductor chip between the central portion and the central portion of the electrode of the main circuit lines of the power semiconductor chip features and to Rupa Wah semiconductor module that has a structure that flows in. 導電性樹脂で接合される主回路配線の電極を加圧する加圧装置を備えたことを特徴とする請求項１〜５のいずれか１項に記載のパワー半導体モジュール。The power semiconductor module according to any one of claims 1-5, characterized in that the electrodes of the joined the main circuit wiring with a pressurizing pressure device with a conductive resin.
JP08547499A 1999-03-29 1999-03-29 Power semiconductor module Expired - Fee Related JP4075199B2 (en)

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