JP3659301B2

JP3659301B2 - Package for storing semiconductor elements

Info

Publication number: JP3659301B2
Application number: JP30829098A
Authority: JP
Inventors: 和弘川畑
Original assignee: Kyocera Corp
Current assignee: Kyocera Corp
Priority date: 1998-10-29
Filing date: 1998-10-29
Publication date: 2005-06-15
Anticipated expiration: 2018-10-29
Also published as: JP2000138332A

Description

【０００１】
【発明の属する技術分野】
本発明はＬＳＩ（大規模集積回路素子）等の半導体素子を収容するための半導体素子収納用パッケージに関するものである。
【０００２】
【従来の技術】
従来、半導体素子を収容するための半導体素子収納用パッケージは、上面に半導体素子が載置される載置部を有する銅、銅ータングステン合金等の金属材料からなる放熱板と、該放熱板の上面に前記載置部を囲繞するようにして取着された酸化アルミニウム質焼結体等の電気絶縁材料から成る枠状の絶縁体と、該枠状絶縁体の内周部から外周部にかけて被着導出されているタングステン、モリブデン、マンガン等の高融点金属粉末からなる複数個のメタライズ配線層と、前記枠状絶縁体の上面に取着され、絶縁体の穴を塞ぐ蓋体とから構成されており、放熱板の半導体素子載置部に半導体素子をガラス、樹脂、ロウ材等の接着剤を介して接着固定するとともに該半導体素子の各電極をボンディングワイヤを介して枠状絶縁体に形成したメタライズ配線層に電気的に接続し、しかる後、枠状絶縁体に蓋体を該絶縁体の穴を塞ぐようにしてガラス、樹脂、ロウ材等から成る封止材を介して接合させ、放熱板と枠状絶縁体と蓋体とから成る容器内部に半導体素子を気密に収容することによって製品としての半導体装置となる。
【０００３】
なお、上述の半導体素子収納用パッケージにおいては、半導体素子が載置される放熱板が銅や銅ータングステン合金等の金属材料で形成されており、該銅や銅ータングステン合金等は熱伝導性に優れていることから放熱板は半導体素子の作動時に発する熱を良好に吸収するとともに大気中に良好に放散させることができ、これによって半導体素子を常に適温とし半導体素子に熱破壊が発生したり、特性に熱劣化が発生したりするのを有効に防止している。
【０００４】
【発明が解決しようとする課題】
しかしながら、この従来の半導体素子収納用パッケージでは、放熱板が銅で形成されている場合、該銅はその熱膨張係数が約１８×１０^-6／℃で枠状絶縁体を構成する酸化アルミニウム質焼結体等の熱膨張係数（酸化アルミニウム質焼結体の熱膨張係数は約７×１０^-6／℃）と大きく相異することから、容器内部に半導体素子を気密に収容し、半導体装置となした後、枠状絶縁体と放熱板の各々に半導体素子が作動時に発生する熱等が印加された場合、放熱板と枠状絶縁体との間に両者の熱膨張係数の相異に起因する大きな熱応力が発生し、該熱応力によって放熱板が枠状絶縁体より剥がれたり、枠状絶縁体に割れやクラックが発生して容器の気密封止が破れ、容器内部に収容する半導体素子を長期間にわたり、正常、且つ安定に作動させることができないという欠点を有していた。
【０００５】
また放熱板が銅ータングステン合金で形成されている場合、該銅ータングステン合金は重いことから容器内部に半導体素子を気密に収容し、半導体装置となした際、半導体装置の重量が重くなり、近時の小型化、軽量化が進む電子装置にはその実装が困難となってしまう欠点を有していた。
【０００６】
本発明は上記欠点に鑑み案出されたもので、その目的は容器内部の気密封止を完全とするとともに容器内部に収容する半導体素子を常に適温として半導体素子を長期間にわたり正常、かつ安定に作動させることができる半導体素子収納用パッケージを提供することにある。
【０００７】
【課題を解決するための手段】
本発明は、上面に半導体素子が載置される載置部を有する放熱板に前記載置部を囲繞するようにして枠状の絶縁体を取着させた半導体素子収納用パッケージであって、前記放熱板は厚み方向に配列した炭素繊維を炭素で結合した一方向性複合材料から成る芯体の上下両面にクロムー鉄合金層、銅層、モリブデン層の３層構造を有する金属層が拡散接合により被着されて形成されており、かつ前記クロムー鉄合金層、銅層、モリブデン層の各々の厚みが略同一厚みであることを特徴とするものである。
【０００８】
本発明の半導体素子収納用パッケージによれば、放熱板として厚み方向に配列した炭素繊維を炭素で結合した一方向性複合材料から成る芯体の上下両面にクロムー鉄合金層、銅層、モリブデン層の３層構造を有する金属層を拡散接合させたものを使用したことから半導体素子が作動時に発した熱は放熱板の上面側から下面側にかけて選択的に伝達されるとともに放熱板の下面側から大気中に効率良く放散されることとなり、その結果、半導体素子は常に適温となり、半導体素子を長期間にわたり正常、かつ安定に作動させることが可能となる。
【０００９】
また本発明の半導体素子収納用パッケージによれば、厚み方向に配列した炭素繊維を炭素で結合した一方向性複合材料から成る芯体の上下両面にクロムー鉄合金層、銅層、モリブデン層の３層構造を有する金属層を拡散接合させた放熱板はその熱膨張係数が約７×１０^-6／℃であり、枠状絶縁体を形成する酸化アルミニウム質焼結体等の熱膨張係数に近似することから、容器内部に半導体素子を気密に収容し、半導体装置となした後、放熱板と枠状絶縁体の各々に半導体素子が作動時に発する熱が印加されたとしても、放熱板と枠状絶縁体との間に両者の熱膨張係数の相違に起因する大きな熱応力が発生することはなく、その結果、放熱板は絶縁体に割れやクラックを発生させることなく絶縁体に強固に接合し、かつ半導体素子の作動時に発する熱を大気中に良好に放散させることを可能として、容器内部に収容する半導体素子を長期間にわたり正常、かつ安定に作動させることができる。
【００１０】
また本発明の半導体素子収納用パッケージによれば、厚み方向に配列した炭素繊維を炭素で結合した一方向性複合材料から成る芯体の上下両面にクロムー鉄合金層、銅層、モリブデン層の３層構造を有する金属層を拡散接合させた放熱板はその重量が銅ータングステン合金に比べて１／５程度であり、極めて軽量なものであることから半導体素子収納用パッケージ内に半導体素子を収容し、半導体装置となした場合、半導体装置の重量は極めて軽量なものとなり、その結果、近時の小型化、軽量化が進む電子装置への実装も可能となる。
【００１１】
【発明の実施の形態】
次に本発明を添付図面に基づき詳細に説明する。
図１及び図２は本発明の半導体素子収納用パッケージの一実施例を示し、１は放熱板、２は枠状の絶縁体、３は蓋体である。この放熱板１と枠状絶縁体２と蓋体３とで半導体素子４を収容する容器５が構成される。
【００１２】
前記放熱板１はその上面に半導体素子４が載置される載置部１ａを有するとともに上面外周部に該放熱板１の上面に設けた半導体素子４が載置される載置部１ａを囲繞するようにして枠状の絶縁体２がロウ材やガラス、樹脂等の接着剤を介して取着されている。
【００１３】
前記放熱板１は半導体素子４を支持する支持部材として作用するとともに半導体素子４が作動時に発する熱を良好に吸収するとともに大気中に効率良く放散させ、半導体素子４を常に適温とする作用をなし、枠状絶縁体２に囲まれた放熱板１の載置部１ａ上に半導体素子４がガラス、樹脂、ロウ材等の接着剤を介して固定される。
【００１４】
前記放熱板１は、図２に示すように、厚み方向に配列した炭素繊維を炭素で結合した一方向性複合材料から成る芯体１ｂの上下両面にクロムー鉄合金層６ａ、銅層６ｂ、モリブデン層６ｃの３層構造を有する金属層６を拡散接合により被着させたものから成り、枠状絶縁体２の下面に予めタングステンやモリブデン、マンガン等の高融点金属粉末から成るメタライズ金属層７を被着させておき、該メタライズ金属層７に放熱坂１の上面側に被着させた金属層６を半田や銀ー銅合金、チタンー銀ー銅合金等のロウ材を介しロウ付けすることによって放熱板１は枠状絶縁体２の下面に取着される。
【００１５】
前記放熱板１の一方向性複合材料から成る芯体１ｂは、例えば、一方向に配列した炭素繊維の束を、固体のピッチあるいはコークスなどの微粉末を分散させたフェノール樹脂などの熱硬化性樹脂の溶液中に含浸させ、次にこれを乾燥させて一方向に炭素繊維が配列している複数枚のシー卜を形成するとともに各々のシー卜を炭素繊維の方向が同一となるようにして複数枚積層し、次に前記積層された複数枚のシー卜に所定の圧力を加えるとともに加熱して熱硬化性樹脂部分を硬化させ、最後にこれを不活性雰囲気中、高温で焼成し、フェノール樹脂とピッチあるいはコークスの微粉末を炭化させる（炭素を形成する）とともに該炭素で各々の炭素繊維を結合させることによって製作されている。
【００１６】
また前記放熱板１の一方向性複合材料からなる芯体１ｂはその上下両面にクロムー鉄合金層６ａと銅層６ｂとモリブデン層６ｃとの３つの層からなる金属層６が被着されており、該金属層６のクロムー鉄合金層６ａと銅層６ｂとモリブデン層６ｃの各々はその厚みが略同一厚みとなっている。
【００１７】
前記金属層６を略同一厚みのクロムー鉄合金層６ａと銅層６ｂとモリブデン層６ｃの３つの層で形成するのは一方向性複合材料からなる芯体１ｂの熱膨張係数を枠状絶縁体２の熱膨張係数に近似する約７×１０^-6／℃にするためであり、一方向性複合材料からなる芯体１ｂの上下両面に略同一厚みのクロムー鉄合金層６ａと銅層６ｂとモリブデン層６ｃの３つの層からなる金属層６を被着させた放熱板１はその熱膨張係数が約７×１０^-6／℃となり、これによって放熱板１を枠状絶縁体２の下面に取着させた後、両者に半導体素子４が作動時に発生する熱等が印加されたとしても、放熱板１と枠状絶縁体２との間には両者の熱膨張係数の相異に起因する大きな熱応力が発生することはなく、その結果、放熱板１は枠状絶縁体２に強固に接合し、かつ半導体素子４の作動時に発する熱を大気中に良好に放散させることを可能として、容器内部に収容する半導体素子４を長期間にわたり、正常、旦つ安定に作動させることができる。
【００１８】
なお、前記金属層６は一方向性複合材料からなる芯体１ｂの上下両面に拡散接合させることによって被着されており、具体的には、一方向性複合材料からなる芯体１ｂの上下両面に厚さ５０μｍ以下のクロムー鉄合金の箔と銅の箔とモリブデンの箔を順次、載置させ、次にこれを真空ホットプレスで５ＭＰａの圧力をかけつつ１２０００ｃの温度を１時間印加することによって行われる。
【００１９】
また前記金属層６のクロムー鉄合金層６ａは、金属層６を一方向性複合材料からなる芯体１ｂに強固に接合させる作用をなし、また銅層６ｂはクロムー鉄合金層６ａとモリブデン層６ｃとを強固に接合させるとともに両者の相互拡散を有効に防止する作用をなし、更にモリブデン層６ｃはクロムー鉄合金層６ａ及び銅層６ｂと相まって放熱板１の熱膨張係数を約７×１０^-6／℃とする作用をなす。
【００２０】
前記一方向性複合材料からなる芯体１ｂの上下両主面に金属層６を被着させてなる放熱板１は、一方向性複合材料からなる芯体１ｂの炭素繊維の方向、即ち、放熱板１の上面から下面にかけての方向の熱伝導率が３００Ｗ／ｍ・ｋ以上、炭素繊維に対し直交する方向の熱伝導率が３０Ｗ／ｍ・ｋ以下であり、放熱板１の上面側から下面側に向けて熱が一方向に選択的に効率良く伝達するようになっている。そのためこの一方向性複合材料から成る芯体１ｂを用いた放熱板１の上面に半導体素子４を載置固定させた場合、半導体素子４の作動時に発する熱は放熱板１の上面から下面にかけて一方向に伝達し、放熱板１の下面から大気中に効率良く放散されることとなる。
【００２１】
前記一方向性複合材料から成る芯体１ｂを用いた放熱板１はまたその重量が銅ータングステン合金に比較して１／５程度であり、軽いことからこの放熱板１を使用した半導体素子収納用パッケージに半導体素子４を収容して半導体装置を形成した際、該半導体装置の重量も極めて軽量なものとなり、近時の小型化、軽量化が進む電子装置にも実装が可能となる。
【００２２】
更に前記一方向性複合材料からなる芯体１ｂを用いた放熱板１はその弾性率が３０ＧＰａ以下であり、軟質であることから放熱板１と枠状絶縁体２との間に若干の熱膨張係数差があったとしても両者間に発生する熱応力は放熱板１を適度に変形させることによって吸収され、その結果、枠状絶縁体２と放熱板１とは極めて強固に接合し、半導体素子４が発する熱を常に大気中へ効率良く放散させることができる。
【００２３】
また更に前記一方向性複合材料からなる芯体１ｂの上下両面に金属層６を被着させた放熱板１は、芯体１ｂと上面金属層６との間及び芯体１ｂと下面金属層６との間に両者の熱膨張係数の相違に起因する熱応力が発生するがその各々の熱応力は金属層６の芯体１ｂに対する被着位置が異なることから互いに相殺され、その結果、放熱板１は芯体１ｂと金属層６との間に発生する熱応力によって変形することはなく常に平坦となり、これによって枠状絶縁体２の下面に放熱板１を強固に接合させることが可能となるとともに半導体素子４が作動時に発する熱を放熱板１を介して大気中に効率良く放散させることが可能となる。
【００２４】
更にまた前記放熱板１の上面外周部に該放熱板１の上面に設けた半導体素子４が載置される載置部１ａを囲繞するようにして枠状の絶縁体２がロウ材やガラス、樹脂等の接着剤を介して取着されており、放熱板１と枠状絶縁体２とで半導体素子４を収容するための空所が内部に形成される。
【００２５】
前記放熱板１に取着される枠状絶縁体２は酸化アルミニウム質焼結体等の電気絶縁材料から成り、例えば、酸化アルミニウム、酸化珪素、酸化マグネシウム、酸化カルシウム等の原料粉末に適当な有機バインダー、溶剤等を添加混合して泥漿物を作るとともに、該泥漿物をドクターブレード法やカレンダーロール法を採用することによってセラミックグリーンシート（セラミック生シート）と成し、しかる後、前記セラミックグリーンシートに適当な打ち抜き加工を施すとともにこれを複数枚積層し、約１６００℃の温度で焼成することによって製作される。
【００２６】
前記枠状絶縁体２は更にその内周部から上面にかけて導出する複数個のメタライズ配線層８が被着形成されており、枠状絶縁体２の内周部に露出するメタライズ配線層８の一端には半導体素子４の各電極がボンディングワイヤ９を介して電気的に接続され、また枠状絶縁体２の上面に導出された部位には外部電気回路と接続される外部リードピン１０が銀ロウ等のロウ材を介してロウ付け取着されている。
【００２７】
前記メタライズ配線層８は半導体素子４の各電極を外部電気回路に接続する際の導電路として作用し、タングステン、モリブデン、マンガン等の高融点金属粉末により形成されている。
【００２８】
前記メタライズ配線層８はタングステン、モリブデン、マンガン等の高融点金属粉末に適当な有機バインダー、溶剤等を添加混合して得た金属ペーストを枠状絶縁体２となるセラミックグリーンシートに予め従来周知のスクリーン印刷法により所定パターンにに印刷塗布しておくことによって枠状絶縁体２の内周部から上面にかけて被着形成される。
【００２９】
なお、前記メタライズ配線層８はその露出する表面にニッケル、金等の耐蝕性に優れ、かつロウ材との濡れ性に優れる金属を１μｍ〜２０μｍの厚みにメッキ法により被着させておくと、メタライズ配線層８の酸化腐蝕を有効に防止することができるとともにメタライズ配線層８への外部リードピン１０のロウ付けを強固となすことができる。従って、前記メタライズ配線層８は、その露出する表面にニッケル、金等の耐蝕性に優れ、かつロウ材との濡れ性に優れる金属を１μｍ〜２０μｍの厚みに被着させておくことが好ましい。
【００３０】
また前記メタライズ配線層８には外部リードピン１０が銀ロウ等のロウ材を介してロウ付け取着されており、該外部リードピン１０は容器５内部に収容する半導体素子４の各電極を外部電気回路に電気的に接続する作用をなし、外部リードピン１０を外部電気回路に接続することによって容器５内部に収容される半導体素子４はメタライズ配線層８及び外部リードピン１０を介して外部電気回路に接続されることとなる。
【００３１】
前記外部リードピン１０は鉄ーニッケルーコバルト合金や鉄ーニッケル合金等の金属材料から成り、例えば、鉄ーニッケルーコバルト合金等の金属から成るインゴット（塊）に圧延加工法や打ち抜き加工法等、従来周知の金属加工法を施すことによって所定の形状に形成される。
【００３２】
かくして上述の半導体素子収納用パッケージによれば、放熱板１の半導体素子載置部１ａ上に半導体素子４をガラス、樹脂、ロウ材等の接着剤を介して接着固定するとともに該半導体素子４の各電極をボンディングワイヤ９を介して所定のメタライズ配線層８に接続させ、しかる後、前記枠状絶縁体２の上面に蓋体３をガラス、樹脂、ロウ材等から成る封止材を介して接合させ、放熱板１、枠状絶縁体２及び蓋体３とから成る容器５内部に半導体素子４を気密に収容することによって製品としての半導体装置となる。
【００３３】
なお、本発明は上述の実施例に限定されるものではなく、本発明の要旨を逸脱しない範囲であれば種々の変更は可能である。
【００３４】
【発明の効果】
本発明の半導体素子収納用パッケージによれば、放熱板として厚み方向に配列した炭素繊維を炭素で結合した一方向性複合材料から成る芯体の上下両面にクロムー鉄合金層、銅層、モリブデン層の３層構造を有する金属層を拡散接合させたものを使用したことから半導体素子が作動時に発した熱は放熱板の上面側から下面側にかけて選択的に伝達されるとともに放熱板の下面側から大気中に効率良く放散されることとなり、その結果、半導体素子は常に適温となり、半導体素子を長期間にわたり正常、かつ安定に作動させることが可能となる。
【００３５】
また本発明の半導体素子収納用パッケージによれば、厚み方向に配列した炭素繊維を炭素で結合した一方向性複合材料から成る芯体の上下両面にクロムー鉄合金層、銅層、モリブデン層の３層構造を有する金属層を拡散接合させた放熱板はその熱膨張係数が約７×１０^-6／℃であり、枠状絶縁体を形成する酸化アルミニウム質焼結体等の熱膨張係数に近似することから、容器内部に半導体素子を気密に収容し、半導体装置となした後、放熱板と枠状絶縁体の各々に半導体素子が作動時に発する熱膨張係数が印加されたとしても、放熱板と枠状絶縁体との間に両者の熱膨張係数の相違に起因する大きな熱応力が発生することはなく、その結果、放熱板は絶縁体に割れやクラックを発生させることなく絶縁体に強固に接合し、かつ半導体素子の作動時に発する熱を大気中に良好に放散させることを可能として、容器内部に収容する半導体素子を長期間にわたり正常、かつ安定に作動させることができる。
【００３６】
また本発明の半導体素子収納用パッケージによれば、厚み方向に配列した炭素繊維を炭素で結合した一方向性複合材料から成る芯体の上下両面にクロムー鉄合金層、銅層、モリブデン層の３層構造を有する金属層を拡散接合させた放熱板はその重量が銅ータングステン合金に比べて１／５程度であり、極めて軽量なものであることから半導体素子収納用パッケージ内に半導体素子を収容し、半導体装置となした場合、半導体装置の重量は極めて軽量なものとなり、その結果、近時の小型化、軽量化が進む電子装置への実装も可能となる。
【図面の簡単な説明】
【図１】本発明の半導体素子収納用パッケージの一実施例を示す断面図である。
【図２】図１に示す半導体素子収納用パッケージの要部拡大断面図である。
【符号の説明】
１・・・・・・・・放熱板
１ａ・・・・・・・半導体素子の載置部
１ｂ・・・・・・・芯体
２・・・・・・・・枠状の絶縁体
３・・・・・・・・蓋体
４・・・・・・・・半導体素子
６・・・・・・・・金属層
６ａ・・・・・・・クロムー鉄合金層
６ｂ・・・・・・・銅層
６ｃ・・・・・・・モリブデン層
８・・・・・・・・メタライズ配線層
１０・・・・・・・・外部リードピン[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a package for housing a semiconductor element for housing a semiconductor element such as an LSI (Large Scale Integrated Circuit Element).
[0002]
[Prior art]
2. Description of the Related Art Conventionally, a package for housing a semiconductor element for housing a semiconductor element includes a heat sink made of a metal material such as copper or copper-tungsten alloy having a mounting portion on which the semiconductor element is mounted, and the heat sink. A frame-shaped insulator made of an electrically insulating material such as an aluminum oxide sintered body attached so as to surround the mounting portion on the upper surface, and a covering from the inner peripheral portion to the outer peripheral portion of the frame-shaped insulator. It consists of a plurality of metallized wiring layers made of refractory metal powders such as tungsten, molybdenum, and manganese, and a lid that is attached to the upper surface of the frame-like insulator and closes the holes of the insulator. The semiconductor element is bonded and fixed to the semiconductor element mounting portion of the heat sink via an adhesive such as glass, resin, or brazing material, and each electrode of the semiconductor element is formed on the frame-like insulator via a bonding wire. Metalla Electrically connected to the wiring layer, and after that, the lid is attached to the frame-like insulator through a sealing material made of glass, resin, brazing material, etc. so as to close the hole of the insulator, and heat dissipation A semiconductor device as a product is obtained by airtightly housing a semiconductor element in a container composed of a plate, a frame-like insulator, and a lid.
[0003]
In the semiconductor element storage package described above, the heat sink on which the semiconductor element is placed is formed of a metal material such as copper or copper-tungsten alloy, and the copper or copper-tungsten alloy is thermally conductive. Therefore, the heat sink can absorb the heat generated during the operation of the semiconductor element well and dissipate it well into the atmosphere. This effectively prevents thermal degradation of the characteristics.
[0004]
[Problems to be solved by the invention]
However, in this conventional package for housing semiconductor elements, when the heat sink is made of copper, the copper has a thermal expansion coefficient of about 18 × 10 ⁻⁶ / ° C., and the aluminum oxide material constituting the frame insulator Since the thermal expansion coefficient of the sintered body and the like (the thermal expansion coefficient of the aluminum oxide sintered body is approximately 7 × 10 ⁻⁶ / ° C.) is greatly different, the semiconductor element is hermetically accommodated inside the container, and the semiconductor device After that, when heat generated during operation of the semiconductor element is applied to each of the frame-shaped insulator and the heat sink, the difference in thermal expansion coefficient between the heat sink and the frame insulator is different. A large thermal stress is generated, and the heat sink is peeled off from the frame insulator by the thermal stress, or the frame insulator is cracked or cracked, and the hermetic seal of the container is broken, and the semiconductor accommodated inside the container Operate the device normally and stably over a long period of time Door had the disadvantage that can not be.
[0005]
Also, when the heat sink is formed of a copper-tungsten alloy, the copper-tungsten alloy is heavy, so the semiconductor element is hermetically accommodated inside the container, and when it becomes a semiconductor device, the weight of the semiconductor device becomes heavy, Recently, electronic devices that are becoming smaller and lighter have the drawback of being difficult to mount.
[0006]
The present invention has been devised in view of the above-mentioned drawbacks, and its purpose is to completely and hermetically seal a semiconductor element over a long period of time by making the semiconductor element housed inside the container completely airtight and always keeping the semiconductor element inside the container at a suitable temperature. An object of the present invention is to provide a package for housing a semiconductor element that can be operated.
[0007]
[Means for Solving the Problems]
The present invention is a package for housing a semiconductor element in which a frame-like insulator is attached so as to surround the mounting portion on a heat sink having a mounting portion on which a semiconductor element is mounted. The heat sink is formed by diffusion bonding of metal layers having a three-layer structure of a chromium-iron alloy layer, a copper layer, and a molybdenum layer on both upper and lower surfaces of a core made of a unidirectional composite material in which carbon fibers arranged in the thickness direction are bonded with carbon. And the chromium-iron alloy layer, the copper layer, and the molybdenum layer have substantially the same thickness.
[0008]
According to the package for housing a semiconductor element of the present invention, a chromium-iron alloy layer, a copper layer, and a molybdenum layer are formed on both upper and lower surfaces of a core body made of a unidirectional composite material in which carbon fibers arranged in the thickness direction as a heat sink are bonded with carbon. Since the metal layer having the three-layer structure is diffusion-bonded, heat generated during operation of the semiconductor element is selectively transmitted from the upper surface side to the lower surface side of the heat radiating plate and from the lower surface side of the heat radiating plate. As a result, the semiconductor element is always at an appropriate temperature, and the semiconductor element can be operated normally and stably over a long period of time.
[0009]
Further, according to the package for housing a semiconductor element of the present invention, a chromium-iron alloy layer, a copper layer, and a molybdenum layer are formed on the upper and lower surfaces of a core made of a unidirectional composite material in which carbon fibers arranged in the thickness direction are bonded with carbon. The heat dissipation plate made by diffusion-bonding a metal layer having a layer structure has a thermal expansion coefficient of about 7 × 10 ⁻⁶ / ° C., and approximates the thermal expansion coefficient of an aluminum oxide sintered body that forms a frame-like insulator. Therefore, after the semiconductor element is hermetically accommodated inside the container to form a semiconductor device, even if heat generated during operation of the semiconductor element is applied to each of the heat sink and the frame-like insulator, the heat sink and the frame Large thermal stress due to the difference in thermal expansion coefficient between the two is not generated between the heat insulator and the heat sink, and as a result, the heat sink is firmly bonded to the insulator without causing cracks or cracks in the insulator. And when the semiconductor device is activated Heat as possible to be favorably dissipated to the atmosphere, normally a semiconductor element housed inside the container for a long period of time, and can be stably operated that.
[0010]
Further, according to the package for housing a semiconductor element of the present invention, a chromium-iron alloy layer, a copper layer, and a molybdenum layer are formed on the upper and lower surfaces of a core made of a unidirectional composite material in which carbon fibers arranged in the thickness direction are bonded with carbon. A heat sink with a diffusion layer bonded to a metal layer having a layer structure is about 1/5 the weight of a copper-tungsten alloy, and is extremely lightweight. In the case of a semiconductor device, however, the weight of the semiconductor device is extremely light, and as a result, it can be mounted on an electronic device that has recently been reduced in size and weight.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
Next, the present invention will be described in detail with reference to the accompanying drawings.
1 and 2 show one embodiment of a package for housing a semiconductor element of the present invention, wherein 1 is a heat sink, 2 is a frame-like insulator, and 3 is a lid. The heat radiating plate 1, the frame-like insulator 2, and the lid 3 constitute a container 5 that houses the semiconductor element 4.
[0012]
The heat radiating plate 1 has a mounting portion 1a on which the semiconductor element 4 is mounted on the upper surface and surrounds the mounting portion 1a on which the semiconductor element 4 provided on the upper surface of the heat radiating plate 1 is mounted on the outer peripheral portion of the upper surface. Thus, the frame-like insulator 2 is attached via an adhesive such as a brazing material, glass, or resin.
[0013]
The heat radiating plate 1 functions as a supporting member for supporting the semiconductor element 4 and absorbs heat generated when the semiconductor element 4 is activated and efficiently dissipates it into the atmosphere, thereby making the semiconductor element 4 always have an appropriate temperature. The semiconductor element 4 is fixed on the mounting portion 1a of the heat sink 1 surrounded by the frame-like insulator 2 through an adhesive such as glass, resin, or brazing material.
[0014]
As shown in FIG. 2, the heat radiating plate 1 has a chromium-iron alloy layer 6a, a copper layer 6b, molybdenum on the upper and lower surfaces of a core body 1b made of a unidirectional composite material in which carbon fibers arranged in the thickness direction are bonded with carbon. The metal layer 6 having a three-layer structure of the layer 6c is deposited by diffusion bonding, and a metallized metal layer 7 made of a refractory metal powder such as tungsten, molybdenum, manganese or the like is previously formed on the lower surface of the frame-like insulator 2. By depositing and brazing the metallized metal layer 7 on the upper surface side of the heat radiating hill 1 with a brazing material such as solder, silver-copper alloy, titanium-silver-copper alloy, etc. The heat sink 1 is attached to the lower surface of the frame-like insulator 2.
[0015]
The core body 1b made of the unidirectional composite material of the heat radiating plate 1 is, for example, a thermosetting material such as a phenol resin in which fine fibers such as solid pitch or coke are dispersed in a bundle of carbon fibers arranged in one direction. The resin solution is impregnated and then dried to form a plurality of sheets with carbon fibers arranged in one direction, and each sheet has the same carbon fiber direction. A plurality of sheets are laminated, and then a predetermined pressure is applied to the laminated sheets and heated to cure the thermosetting resin portion, and finally, this is baked at a high temperature in an inert atmosphere. It is manufactured by carbonizing a resin and fine powder of pitch or coke (forming carbon) and bonding each carbon fiber with the carbon.
[0016]
Further, the core 1b made of the unidirectional composite material of the heat radiating plate 1 is coated with a metal layer 6 composed of three layers of a chromium-iron alloy layer 6a, a copper layer 6b, and a molybdenum layer 6c on both upper and lower surfaces. The chromium-iron alloy layer 6a, the copper layer 6b and the molybdenum layer 6c of the metal layer 6 have substantially the same thickness.
[0017]
The metal layer 6 is formed of three layers of a chromium-iron alloy layer 6a, a copper layer 6b, and a molybdenum layer 6c having substantially the same thickness. The thermal expansion coefficient of the core 1b made of a unidirectional composite material is determined as a frame-like insulator. Is approximately 7 × 10 ⁻⁶ / ° C., which approximates the thermal expansion coefficient of 2, and the chrome-iron alloy layer 6a and the copper layer 6b having substantially the same thickness on the upper and lower surfaces of the core 1b made of a unidirectional composite material, The heat radiating plate 1 to which the metal layer 6 composed of three layers of the molybdenum layer 6c is deposited has a thermal expansion coefficient of about 7 × 10 ⁻⁶ / ° C., so that the heat radiating plate 1 is placed on the lower surface of the frame insulator 2. Even if the heat generated during the operation of the semiconductor element 4 is applied to both after the attachment, the heat dissipation plate 1 and the frame-like insulator 2 are caused by the difference in thermal expansion coefficient between them. Large thermal stress is not generated, and as a result, the heat sink 1 is firmly bonded to the frame insulator 2. And the heat generated during operation of the semiconductor element 4 as possible to be favorably dissipated to the atmosphere, over an extended period of time of the semiconductor device 4 which accommodates the inner container, normally, it is possible to operate Dantsu stably.
[0018]
The metal layer 6 is applied by diffusion bonding to the upper and lower surfaces of the core body 1b made of a unidirectional composite material. Specifically, the upper and lower surfaces of the core body 1b made of a unidirectional composite material are attached. A chrome-iron alloy foil, a copper foil and a molybdenum foil having a thickness of 50 μm or less are successively placed on the substrate, and then a temperature of 12000 c is applied for 1 hour while applying a pressure of 5 MPa with a vacuum hot press. Done.
[0019]
The chromium-iron alloy layer 6a of the metal layer 6 serves to firmly bond the metal layer 6 to the core 1b made of a unidirectional composite material, and the copper layer 6b is composed of the chromium-iron alloy layer 6a and the molybdenum layer 6c. And the molybdenum layer 6c, together with the chromium-iron alloy layer 6a and the copper layer 6b, has a coefficient of thermal expansion of about 7 × 10 ^−6. / C.
[0020]
The heat radiating plate 1 in which the metal layers 6 are attached to the upper and lower main surfaces of the core 1b made of the unidirectional composite material is the direction of the carbon fibers of the core 1b made of the unidirectional composite material, that is, the heat dissipation. The thermal conductivity in the direction from the upper surface to the lower surface of the plate 1 is 300 W / m · k or more, and the thermal conductivity in the direction orthogonal to the carbon fiber is 30 W / m · k or less. Heat is transferred selectively and efficiently in one direction toward the side. Therefore, when the semiconductor element 4 is placed and fixed on the upper surface of the heat sink 1 using the core 1b made of this unidirectional composite material, the heat generated during the operation of the semiconductor element 4 is one from the upper surface to the lower surface of the heat sink 1. It is transmitted in the direction and is efficiently dissipated from the lower surface of the heat radiating plate 1 into the atmosphere.
[0021]
The heat sink 1 using the core body 1b made of the unidirectional composite material is also about 1/5 the weight of the copper-tungsten alloy, so that the semiconductor element housing using the heat sink 1 is light. When a semiconductor device is formed by accommodating the semiconductor element 4 in a package for use, the weight of the semiconductor device becomes extremely light, and it can be mounted on an electronic device that has recently been reduced in size and weight.
[0022]
Furthermore, since the heat sink 1 using the core 1b made of the unidirectional composite material has a modulus of elasticity of 30 GPa or less and is soft, it has a slight thermal expansion between the heat sink 1 and the frame insulator 2. Even if there is a coefficient difference, the thermal stress generated between the two is absorbed by appropriately deforming the heat sink 1, and as a result, the frame-like insulator 2 and the heat sink 1 are joined very firmly, and the semiconductor element The heat generated by 4 can always be efficiently dissipated into the atmosphere.
[0023]
Furthermore, the heat radiating plate 1 in which the metal layers 6 are attached to the upper and lower surfaces of the core 1b made of the unidirectional composite material is between the core 1b and the upper surface metal layer 6 and between the core 1b and the lower surface metal layer 6. The thermal stress due to the difference in thermal expansion coefficient between the two is generated between the two and the thermal stresses are offset from each other because the positions where the metal layer 6 is attached to the core 1b are different. 1 is always flat without being deformed by the thermal stress generated between the core 1 b and the metal layer 6, thereby making it possible to firmly bond the heat sink 1 to the lower surface of the frame-like insulator 2. At the same time, it is possible to efficiently dissipate heat generated during operation of the semiconductor element 4 into the atmosphere via the heat radiating plate 1.
[0024]
Furthermore, the frame-like insulator 2 is made of brazing material or glass so as to surround the mounting portion 1a on which the semiconductor element 4 provided on the upper surface of the heat sink 1 is placed on the outer peripheral portion of the upper surface of the heat sink 1. It is attached via an adhesive such as a resin, and a space for accommodating the semiconductor element 4 is formed inside the heat sink 1 and the frame-like insulator 2.
[0025]
The frame-like insulator 2 attached to the heat radiating plate 1 is made of an electrically insulating material such as an aluminum oxide sintered body. For example, an organic material suitable for raw material powders such as aluminum oxide, silicon oxide, magnesium oxide, and calcium oxide. A mud is made by adding and mixing a binder, a solvent, etc., and the mud is made into a ceramic green sheet (ceramic raw sheet) by adopting a doctor blade method or a calender roll method, and then the ceramic green sheet A suitable punching process is applied to the substrate, and a plurality of such layers are laminated and fired at a temperature of about 1600 ° C.
[0026]
The frame-like insulator 2 is further formed with a plurality of metallized wiring layers 8 led out from the inner periphery to the upper surface, and one end of the metallized wiring layer 8 exposed at the inner periphery of the frame-like insulator 2. Each electrode of the semiconductor element 4 is electrically connected via a bonding wire 9, and an external lead pin 10 connected to an external electric circuit is connected to an external electric circuit at a portion led to the upper surface of the frame-like insulator 2. It is brazed and attached via a brazing material.
[0027]
The metallized wiring layer 8 functions as a conductive path for connecting each electrode of the semiconductor element 4 to an external electric circuit, and is formed of a refractory metal powder such as tungsten, molybdenum, or manganese.
[0028]
The metallized wiring layer 8 is previously known in advance in a ceramic green sheet to be a frame-like insulator 2 using a metal paste obtained by adding and mixing an appropriate organic binder, solvent, etc. to a refractory metal powder such as tungsten, molybdenum or manganese. By coating and applying in a predetermined pattern by a screen printing method, the frame-shaped insulator 2 is deposited from the inner periphery to the upper surface.
[0029]
The metallized wiring layer 8 is formed by depositing a metal having excellent corrosion resistance such as nickel and gold on the exposed surface and excellent wettability with a brazing material to a thickness of 1 μm to 20 μm by a plating method. The oxidation corrosion of the metallized wiring layer 8 can be effectively prevented, and the brazing of the external lead pins 10 to the metallized wiring layer 8 can be strengthened. Therefore, the metallized wiring layer 8 is preferably coated with a metal having excellent corrosion resistance such as nickel and gold and excellent wettability with the brazing material on the exposed surface to a thickness of 1 μm to 20 μm.
[0030]
External lead pins 10 are brazed and attached to the metallized wiring layer 8 via a brazing material such as silver solder, and the external lead pins 10 connect each electrode of the semiconductor element 4 accommodated inside the container 5 to an external electric circuit. The semiconductor element 4 accommodated in the container 5 is connected to the external electric circuit through the metallized wiring layer 8 and the external lead pin 10 by connecting the external lead pin 10 to the external electric circuit. The Rukoto.
[0031]
The external lead pin 10 is made of a metal material such as iron-nickel-cobalt alloy or iron-nickel alloy. For example, an ingot made of a metal such as iron-nickel-cobalt alloy is conventionally processed by a rolling method or a punching method. It is formed into a predetermined shape by applying a known metal processing method.
[0032]
Thus, according to the above-described package for housing a semiconductor element, the semiconductor element 4 is bonded and fixed onto the semiconductor element mounting portion 1a of the heat radiating plate 1 through an adhesive such as glass, resin, brazing material, and the like. Each electrode is connected to a predetermined metallized wiring layer 8 via a bonding wire 9, and then the lid 3 is placed on the upper surface of the frame-like insulator 2 via a sealing material made of glass, resin, brazing material or the like. A semiconductor device as a product is obtained by bonding and housing the semiconductor element 4 in a container 5 including the heat radiating plate 1, the frame-like insulator 2, and the lid 3.
[0033]
In addition, this invention is not limited to the above-mentioned Example, A various change is possible if it is a range which does not deviate from the summary of this invention.
[0034]
【The invention's effect】
According to the package for housing a semiconductor element of the present invention, a chromium-iron alloy layer, a copper layer, and a molybdenum layer are formed on both upper and lower surfaces of a core body made of a unidirectional composite material in which carbon fibers arranged in the thickness direction as a heat sink are bonded with carbon. Since the metal layer having the three-layer structure is diffusion-bonded, heat generated during operation of the semiconductor element is selectively transmitted from the upper surface side to the lower surface side of the heat radiating plate and from the lower surface side of the heat radiating plate. As a result, the semiconductor element is always at an appropriate temperature, and the semiconductor element can be operated normally and stably over a long period of time.
[0035]
Further, according to the package for housing a semiconductor element of the present invention, a chromium-iron alloy layer, a copper layer, and a molybdenum layer are formed on the upper and lower surfaces of a core made of a unidirectional composite material in which carbon fibers arranged in the thickness direction are bonded with carbon. The heat dissipation plate made by diffusion-bonding a metal layer having a layer structure has a thermal expansion coefficient of about 7 × 10 ⁻⁶ / ° C., and approximates the thermal expansion coefficient of an aluminum oxide sintered body that forms a frame-like insulator. Therefore, after the semiconductor element is hermetically accommodated inside the container and becomes a semiconductor device, even if a thermal expansion coefficient generated during operation of the semiconductor element is applied to each of the heat sink and the frame-like insulator, the heat sink No large thermal stress due to the difference in thermal expansion coefficient between the two and the frame-like insulator is generated, and as a result, the heat sink is strong in the insulator without causing cracks or cracks in the insulator. And the fabrication of semiconductor elements The heat generated when the enable be favorably dissipated to the atmosphere, normally a semiconductor element housed inside the container for a long period of time, and can be stably operated.
[0036]
Further, according to the package for housing a semiconductor element of the present invention, a chromium-iron alloy layer, a copper layer, and a molybdenum layer are formed on the upper and lower surfaces of a core made of a unidirectional composite material in which carbon fibers arranged in the thickness direction are bonded with carbon. A heat sink with a diffusion layer bonded to a metal layer having a layer structure is about 1/5 the weight of a copper-tungsten alloy, and is extremely lightweight. In the case of a semiconductor device, however, the weight of the semiconductor device is extremely light, and as a result, it can be mounted on an electronic device that has recently been reduced in size and weight.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view showing an embodiment of a package for housing a semiconductor element of the present invention.
2 is an enlarged cross-sectional view of a main part of the package for housing a semiconductor element shown in FIG.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ...... Radiating plate 1a ... Semiconductor element mounting part 1b ... Core 2 ... Frame-shaped insulator 3 ... Lid 4 ... Semiconductor element 6 ... Metal layer 6a ... Chrome-iron alloy layer 6b ... ··· Copper layer 6c ··· Molybdenum layer 8 ··· Metallized wiring layer 10 ··· External lead pin

Claims

A package for housing a semiconductor element, wherein a frame-like insulator is attached to a heat sink having a mounting portion on which a semiconductor element is mounted so as to surround the mounting portion. A metal layer having a three-layer structure of a chromium-iron alloy layer, a copper layer, and a molybdenum layer is deposited by diffusion bonding on the upper and lower surfaces of a core made of a unidirectional composite material in which carbon fibers arranged in the thickness direction are bonded with carbon. A package for housing a semiconductor element, wherein the chromium-iron alloy layer, the copper layer, and the molybdenum layer have substantially the same thickness.