JP3886626B2 - Manufacturing method of heat sink for semiconductor device - Google Patents

Manufacturing method of heat sink for semiconductor device Download PDF

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JP3886626B2
JP3886626B2 JP35108497A JP35108497A JP3886626B2 JP 3886626 B2 JP3886626 B2 JP 3886626B2 JP 35108497 A JP35108497 A JP 35108497A JP 35108497 A JP35108497 A JP 35108497A JP 3886626 B2 JP3886626 B2 JP 3886626B2
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JPH11186474A (en
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祥治 小泉
俊一 梅本
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Shinko Electric Industries Co Ltd
Kobe Steel Ltd
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Shinko Electric Industries Co Ltd
Kobe Steel Ltd
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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L2224/00—Indexing scheme for arrangements for connecting or disconnecting semiconductor or solid-state bodies and methods related thereto as covered by H01L24/00
    • H01L2224/01—Means for bonding being attached to, or being formed on, the surface to be connected, e.g. chip-to-package, die-attach, "first-level" interconnects; Manufacturing methods related thereto
    • H01L2224/42—Wire connectors; Manufacturing methods related thereto
    • H01L2224/47—Structure, shape, material or disposition of the wire connectors after the connecting process
    • H01L2224/48—Structure, shape, material or disposition of the wire connectors after the connecting process of an individual wire connector
    • H01L2224/4805—Shape
    • H01L2224/4809—Loop shape
    • H01L2224/48091—Arched
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L2224/00—Indexing scheme for arrangements for connecting or disconnecting semiconductor or solid-state bodies and methods related thereto as covered by H01L24/00
    • H01L2224/01—Means for bonding being attached to, or being formed on, the surface to be connected, e.g. chip-to-package, die-attach, "first-level" interconnects; Manufacturing methods related thereto
    • H01L2224/42—Wire connectors; Manufacturing methods related thereto
    • H01L2224/47—Structure, shape, material or disposition of the wire connectors after the connecting process
    • H01L2224/48—Structure, shape, material or disposition of the wire connectors after the connecting process of an individual wire connector
    • H01L2224/481—Disposition
    • H01L2224/48151—Connecting between a semiconductor or solid-state body and an item not being a semiconductor or solid-state body, e.g. chip-to-substrate, chip-to-passive
    • H01L2224/48221—Connecting between a semiconductor or solid-state body and an item not being a semiconductor or solid-state body, e.g. chip-to-substrate, chip-to-passive the body and the item being stacked
    • H01L2224/48225—Connecting between a semiconductor or solid-state body and an item not being a semiconductor or solid-state body, e.g. chip-to-substrate, chip-to-passive the body and the item being stacked the item being non-metallic, e.g. insulating substrate with or without metallisation
    • H01L2224/48227—Connecting between a semiconductor or solid-state body and an item not being a semiconductor or solid-state body, e.g. chip-to-substrate, chip-to-passive the body and the item being stacked the item being non-metallic, e.g. insulating substrate with or without metallisation connecting the wire to a bond pad of the item
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L2224/00—Indexing scheme for arrangements for connecting or disconnecting semiconductor or solid-state bodies and methods related thereto as covered by H01L24/00
    • H01L2224/01—Means for bonding being attached to, or being formed on, the surface to be connected, e.g. chip-to-package, die-attach, "first-level" interconnects; Manufacturing methods related thereto
    • H01L2224/42—Wire connectors; Manufacturing methods related thereto
    • H01L2224/47—Structure, shape, material or disposition of the wire connectors after the connecting process
    • H01L2224/49—Structure, shape, material or disposition of the wire connectors after the connecting process of a plurality of wire connectors
    • H01L2224/491—Disposition
    • H01L2224/49105—Connecting at different heights
    • H01L2224/49109—Connecting at different heights outside the semiconductor or solid-state body

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  • Straightening Metal Sheet-Like Bodies (AREA)
  • Forging (AREA)
  • Cooling Or The Like Of Semiconductors Or Solid State Devices (AREA)

Description

【０００１】
【発明の属する技術分野】
本発明は半導体装置用放熱板の製造方法に関し、更に詳細には金属製プレートの一面側に突出する凸部の上面に形成された平坦面に、半導体素子が搭載される半導体装置用放熱板の製造方法に関する。
【０００２】
【従来の技術】
半導体装置１００には、図８に示す多層Ｐ−ＰＧＡ（Multi Layer Plastic Pin Grid Array）型のものがある。この半導体装置１００は、多層のプラスチック基板１０２の各層間に形成された導体パターン１０４、１０４・・と電気的に接続された複数本のピン１０６、１０６・・が、プラスチック基板１０２に形成された貫通孔内に立設され、且つキャビティ１０８の底面が銅や銅合金等から成る金属製プレート１１０によって形成されている。かかる金属製プレート１０４の凸部１１８の平坦面には、半導体素子１１２が搭載され、搭載された半導体素子１１２は導体パターン１０４の各々とボンディングワイヤ１１４、１１４・・によって電気的に接続される。
この様に、半導体素子１１２を金属製プレート１１０に搭載することにより、半導体装置１００の放熱性が向上できる。
尚、金属製プレート１１０に搭載された半導体素子１１２等は、キャビティ１０８の開口部に装着されたキャップ１１６によって封止される。
【０００３】
かかる金属製プレート１１０には、その斜視図である図９（ａ）及びＹ−Ｙ面における断面図である図９（ｂ）に示す様に、中央部近傍に半導体素子１１２が搭載される平坦面が上面に形成された凸部１１８が設けられている。
この凸部１１８の平坦面である上面１１８ａは、極めて高度な平坦度が要求されるため、従来、金属製プレート１１０の凸部１１８を研削加工によって形成していた。
【０００４】
【発明が解決しようとする課題】
研削加工によって形成された金属製プレート１１０は、凸部１１８の上面１１８ａを極めて高度の平坦度に仕上げることができる。
しかし、金属製プレート１１０を研削加工によって製造することは、金属製プレート１１０の加工コストが高額となるため、最終的に得られる半導体装置も高額となる。更に、研削加工では金属製プレート１１０の加工速度の向上を容易に図ることができず、生産能力にも限界が生じ易い。
このため、本発明者等は、研削加工よりも製造コストを低減でき且つ優れた生産能力を有する冷間鍛造（プレス加工）によって、図９に示す金属製プレート１１０を製造する製造方法を試みた。この製造方法は、金属製プレートの一面側からプレス加工を施して凸部を形成するものであるが、この製造方法では、金属製プレート１１０の外周方向への延びが生じてしまうため好ましくない。
一方、金属製プレートの一面側に凹部をプレス加工によって形成し、金属製プレートの他面側に凸部を突出する製造方法によれば、金属製プレート１１０の外周方向への延びを抑制できる。しかしながら、かかる製造方法によって形成した金属製プレート１１０は、凸部１１８の上面１１８ａの平坦度が、研削加工して得た金属製プレートの凸部の上面よりも劣るため、半導体素子を搭載する放熱板としては到底採用し得ないことが判明した。
唯、金属製プレート１１０にプレス加工によって形成した凸部１１８の上面１１８ａの平坦化を図ることができれば、研削加工よりも低コストの金属製プレート１１０を大量に且つ安価に供給することが可能である。
そこで、本発明の課題は、金属製プレートの外周方向への延びを抑制しつつプレス加工して得られた金属製プレートの凸部の平坦面を、半導体素子を搭載し得るように平坦化し得る半導体装置用放熱板の製造方法を提供することにある。
【０００５】
【課題を解決するための手段】
本発明者等は、前記課題を解決すべく、先ず、金属製プレートの一面側に凹部をプレス加工によって形成し、金属製プレートの他面側に凸部を突出させて得た金属製プレートに形成した凸部の上面の平坦度が研削加工したものよりも劣る原因について検討したところ、プレス加工に因る加工歪みが内在していること、及びプレス加工においては、通常、コイル状に巻いた金属帯状体を使用するため、得られた金属製プレートには、コイル状に巻かれた際の巻き癖が残留していることに因るものと考えられる。
このため、本発明者等は、プレス加工によって得た金属製プレートを、その各面の凹凸形状に倣う一対のスペーサを用いて挟み込みつつ平坦化処理を施すことによって、凸部の上面が高度に平坦化された金属製プレートを得ることができることを見出し、本発明に到達した。
【０００６】
すなわち、本発明は、金属製プレートの一面側に突出する凸部の上面に形成された平坦面に、半導体素子が搭載される半導体装置用放熱板を製造する際に、該金属製プレートの他面側に凹部をプレス加工によって形成し、前記凹部に対応する凸部を金属製プレートの一面側に突出させた後、前記凸部を形成した金属製プレートを、前記金属製プレートの凸部に対応する凹部が形成された第１スペーサと、前記金属製プレートの凹部に対応する凸部が形成された第２スペーサとの間に、前記第１スペーサの凹部の底面と金属製プレートの凸部の上面とを当接させると共に、前記第１スペーサの凹部形成面と金属製プレートの凸部形成面との間にクリアランスを設けて挟み込み、次いで、前記第１スペーサと第２スペーサとによって挟み込まれた金属製プレートを加圧しつつ加熱処理を施して前記金属製プレートの凸部の上面を平坦化することを特徴とする半導体装置用放熱板の製造方法にある。
【０００７】
かかる本発明において、金属製プレートの凸部を、冷間鍛造によって形成することによって、温間鍛造の如く、プレス加工後の金属製プレートの熱収縮等を配慮することを必要とせず好ましい。
また、第１スペーサの凹部形成面と金属製プレートの凸部形成面との間のクリアランスを０．００５〜０．２ｍｍとすることが好ましい。更に、第２スペーサの凸部形成面と金属製プレートの凹部形成面とを当接すると共に、前記第２スペーサの凸部の上面と金属製プレートの凹部の底面との間にもクリアランスを形成することにより、金属製プレートの凹部形成面の平坦化も図ることができる。
この第１スペーサと第２スペーサとを、金属製プレートと同一金属によって形成した金属製のスペーサを用いることによって、第１スペーサ及び第２スペーサと金属製プレートとの相互矯正を図ることができる。この様に、金属製のスペーサを用いる場合、加熱処理の温度を、金属製プレートの軟化点よりも低温であって、前記金属製プレートと金属製スペーサとが接着することのない温度とすることによって、両者の接着を防止できる。
また、第１スペーサと第２スペーサとの間に挟み込む金属製プレートとして、他面側に複数個の凹部をプレス加工によって一列に形成し、前記凹部の各々に対応する凸部を一面側に突出させた帯状金属製プレートを用い、前記第１スペーサと第２スペーサとによって挟み込まれた前記帯状金属製プレートを加圧しつつ加熱処理した後、前記帯状金属製プレートの凸部間の所定箇所を切断して個片の金属製プレートとすることにより、半導体装置用放熱板の生産効率を更に向上できる。
【０００８】
本発明によれば、プレス加工によって上面が平坦面である凸部が形成された金属製プレートを第１スペーサと第２スペーサとの間に挟み込む際に、金属製プレートの凸部の上面が第１スペーサに形成された凹部の底面と当接したとき、第１スペーサの凹部形成面と金属製プレートの凸部形成面との間にクリアランスが形成される。このため、第１スペーサの凹部形成面と金属製プレートの凸部形成面とが、金属製プレートの凸部の上面と第１スペーサに形成された凹部の底面とが当接する前に当接することを防止できる。
従って、金属製プレートの凸部の上面は、第１スペーサに形成された凹部の底面に確実に当接した状態で、第１スペーサと第２スペーサとによって所定圧力で挟まれて加熱処理が施されるため、金属製プレートの凸部の上面の平坦度を向上できる結果、この凸部の上面に半導体素子の背面を確実に接合できる。
【０００９】
【発明の実施の形態】
本発明に係る半導体装置用放熱板として用いる金属製プレートは、図１（ａ）に示す様に、アルミニウムから成る帯状金属製プレート１０の一面側１４に、その長手方向に沿って上面が平坦面である凸部１２、１２・・を一列に形成した後、凸部１２間の所定箇所〔図１（ａ）の一点鎖線Ａで示す箇所〕で切断して得ることができる。
かかる帯状金属製プレート１０の凸部１２、１２・・は、冷間鍛造（プレス加工）によって形成する。このプレス加工においては、所定長さに切断された帯状金属製プレート１０の他面側１６に、図１（ａ）のＸ−Ｘ面における横断面である図１（ｂ）に示す様に、凹部１８をプレス加工により形成した際に、凹部１８に対応する帯状金属製プレート１０の一面側１４の箇所が突出して凸部１２を形成する。
尚、このプレス加工においては、凹部１８の開口面積が凸部１２の突出面積よりも若干小さくなるように、凹部１８を形成することが好ましい。
【００１０】
この様な、帯状金属製プレート１０には、プレス加工による加工歪み等の種々の残留応力が残留しており、帯状金属製プレート１０の平坦度が充分でなく、平坦面である凸部１２の上面１２ａ（以下、凸部平坦面１２ａと称することもある）には、半導体素子を搭載することはできない。
この残留応力には、帯状金属製プレート１０の原材であるアルミニウムプレートについたコイル状の巻き癖も含まれる。つまり、アルミニウムプレートは、通常、コイル状に巻かれた金属帯状体から切り取られて用いられるため、コイル状の巻き癖が残留している状態でプレス加工が施されるためである。
【００１１】
かかる残留応力を除去して凸部平坦面１２ａの平坦度を向上するには、金属製プレート１０の凸部平坦面１２ａを拘束状態で加熱処理する平坦化処理を施すことによって行うことができる。
図１に示す帯状金属製プレート１０には、その一面側１４（以下、凸部形成面１４と称することがある）及び他面側１６（以下、凹部形成面１６と称することがある）に凸部１２や凹部１８等の凹凸が形成されている。このため、図２に示す様に、表面側又は裏面側が帯状金属製プレート１０の凸部形成面１４又は凹部形成面１６の形状に倣って形成された一対の第１スペーサ２０と第２スペーサ２２とを用い、帯状金属製プレート１０を第１スペーサ２０と第２スペーサ２２との間に挟み込むことによって、帯状金属製プレート１０の凸部平坦面１２ａに平坦化処理を容易に施すことができる。
この一対の第１スペーサ２０と第２スペーサ２２とは、帯状金属製プレート１０と略同一のサイズであり、帯状金属製プレート１０の凸部形成面１４側に装着される第１スペーサ２０は、その表面側３２は平坦面に形成されているが、金属製プレート１０の凸部形成面１４に対応する裏面側２４（以下、凹部形成面２４と称することがある）には、帯状金属製プレート１０の凸部形成面１４に形成された凸部１２が挿入される凹部２６が形成されている。
他方、帯状金属製プレート１０の凹部形成面１６に装着される第２スペーサ２２は、その裏面側３４が平坦面に形成されているが、帯状金属製プレート１０の凹部形成面１６に対応する表面側２８（以下、凸部形成面２８と称することがある）には、帯状金属製プレート１０の凹部形成面１６に形成された凹部１８に挿入される凸部３０が形成されている。
【００１２】
かかる一対の第１スペーサ２０と第２スペーサ２２との各々を、帯状金属製プレート１０の所定面に装着することによって、図３に示す様に、一対の第１スペーサ２０と第２スペーサ２２とによって帯状金属製プレート１０を挟み込むことができる。
この際、第１スペーサ２０に形成した凹部２６の底面２６ａ（以下、凹部底面２６ａと称することがある）と、帯状金属製プレート１０の凸部平坦面１２ａとを当接させることが大切である。かかる第１スペーサ２０の凹部底面２６ａと帯状金属製プレート１０の凸部平坦面１２ａとを当接させることなく、後述の平坦化処理を施しても、帯状金属製プレート１０の凸部平坦面１２ａを充分な平坦度とすることができない。
ここで、第１スペーサ２０の凹部底面２６ａと帯状金属製プレート１０の凸部平坦面１２ａとを確実に当接させるためには、図３に示す様に、第１スペーサ２０の凹部底面２６ａと帯状金属製プレート１０の凸部平坦面１２ａとが当接したとき、第１スペーサ２０の凹部形成面２４と金属製プレート１０の凸部形成面１４との間にクリアランスｔ1 を設ける。このクリアランスｔ1 を設けることによって、第１スペーサ２０及び帯状金属製プレート１０の加工精度等に因り、第１スペーサ２０の凹部底面２６ａと帯状金属製プレート１０の凸部平坦面１２ａとの当接よりも先に、第１スペーサ２０の凹部形成面２４と帯状金属製プレート１０の凸部形成面１４とが当接する事態を回避できる。
【００１３】
他方、帯状金属製プレート１０を切断して得た半導体装置用放熱板の裏面（半導体素子が搭載される面に対して反対側となる面）に放熱フィン等を装着する予定がない場合には、半導体装置用放熱板の裏面となる帯状金属製プレート１０の凹部形成面１６又は凹部１８の底面のいずれにも厳格な平坦性が要求されず、帯状金属製プレート１０と第２スペーサ２２とが当接した際に、両者のいずれかの箇所にクリアランスを設ける必要はない。
但し、放熱フィン等を装着すべく、帯状金属製プレート１０の凹部形成面１６の平坦性が要求される場合には、図４に示す様に、帯状金属製プレート１０の凹部形成面１６と第２スペーサ２２の凸部形成面２８とが当接したとき、帯状金属製プレート１０の凹部１８の底面と第２スペーサ２２の凸部３０の上面との間にクリアランスｔ2 を形成し、帯状金属製プレート１０の凹部形成面１６と第２スペーサ２２の凸部形成面２８とを確実に当接させることが好ましい。
尚、半導体装置用放熱板の裏面に形成された凹部１８に、放熱フィン等を装着する場合には、帯状金属製プレート１０の凹部形成面１６と第２スペーサ２２の凸部形成面２８とが当接したとき、帯状金属製プレート１０の凹部１８の底面と第２スペーサ２２の凸部３０の平坦面である上面との間にクリアランスｔ2 を形成し、帯状金属製プレート１０の凹部形成面１６と第２スペーサ２２の凸部形成面２８とを確実に当接できるようにする。
【００１４】
本発明においては、図３又は図４に示す様に、一対の第１スペーサ２０と第２スペーサ２２とによって帯状金属製プレート１０を挟み込み、帯状金属製プレート１０の両面に対応する一対の第１スペーサ２０と第２スペーサ２２との平坦面である表面側３２と裏面側３４とに力Ｆ１、Ｆ２を加えることによって、帯状金属製プレート１０を所定圧力で挟み込むことができる。
更に、本発明では、図３又は図４に示す様に、一対の第１スペーサ２０と第２スペーサ２２とによって所定圧力で挟み込んだ状態で帯状金属製プレート１０に平坦化処理を施す。
この平坦化処理では、帯状金属製プレート１０に加熱処理を施した後、冷却処理を施す。先ず、加熱処理においては、図５に示す帯状金属製プレート１０のロックウエル硬さ（ＨR ）と温度との関係を示すグラフにおいて、ＨR が急激に低下する矢印Ｂで示す変曲点（軟化点）近傍の温度で所定時間保持することが好ましい。この変曲点（軟化点）の温度は、金属の種類によって変わるため、平坦化処理を施す帯状金属製プレート１０を形成する金属について予め調査しておくことが好ましい。
この加熱処理は、帯状金属製プレート１０が酸化され易い金属から成る場合、窒素雰囲気中や真空中等の非酸化雰囲気下で施すことが好ましい。
ここで、帯状金属製プレート１０がアルミニウムによって形成されている場合、金属製プレート１０を一対のスペーサ２０、２２によって０．５〜１．０ｋｇ／ｃｍ2 の力で挟み込み、２００〜３００℃で１〜２時間の加熱処理を施すことが好ましい。
【００１５】
かかる加熱処理を施した後、一対の第１スペーサ２０と第２スペーサ２２とに挟み込んだ状態で金属製プレート１０に冷却処理を施す。この冷却処理は、一対の第１スペーサ２０と第２スペーサ２２とに挟み込まれた帯状金属プレート１０を、加熱炉等の加熱雰囲気中から徐々に雰囲気温度が低下するように制御された冷却雰囲気中を通過させて冷却してもよく、加熱雰囲気中から室温下に取り出して放冷してもよい。
室温近傍まで冷却された一対の第１スペーサ２０と第２スペーサ２２との間から帯状金属製プレート１０を取り出すことによって、凸部平坦面１２ａ等の平坦度が著しく向上された帯状金属製プレート１０を得ることができる。このため、得られた帯状金属製プレート１０を、凸部１２間の所定箇所〔図１（ａ）の一点鎖線Ａで示す箇所〕で切断することによって、半導体装置用放熱板を得ることができる。この放熱板の凸部１２の上面に形成された凸部平坦面１２ａは、その平坦度が著しく向上されおり、半導体素子を搭載できる。
また、図４に示す様に、帯状金属製プレート１０の凹部形成面１６と第２スペーサ２２の凸部形成面２８とを当接させて平坦化処理を施した帯状金属製プレート１０から形成された半導体装置用放熱板は、半導体素子が搭載される凸部平坦面１２ａ及び放熱フィン等が装着される凹部形成面１６の平坦度を著しく向上できる。
ここで、冷却処理の途中において、一対の第１スペーサ２０と第２スペーサ２２との間から帯状金属製プレート１０を取り出すと、帯状金属製プレート１０の熱収縮等に因る凹凸が帯状金属製プレート１０の凸部平坦面１２ａや凹部形成面１６に発生し易い。
【００１６】
この様に、帯状金属製プレート１０を挟み込んで平坦化処理を施す一対の第１スペーサ２０と第２スペーサ２２としては、セラミックやタングステンカーバイト等の帯状金属製プレート１０よりも著しく軟化点温度の高い材料で形成したものであってもよいが、平坦化処理を施す帯状金属製プレート１０と同一金属によって形成した一対の第１スペーサ２０と第２スペーサ２２とを用いることによって、一対の第１スペーサ２０と第２スペーサ２２と帯状金属製プレート１０との相互矯正を図ることができ好ましい。
但し、この場合、加熱処理では、帯状金属製プレート１０と第１スペーサ２０及び第２スペーサ２２との接着を防止すべく、帯状金属製プレート１０の軟化点温度よりも低温であって、帯状金属製プレート１０と一対の第１スペーサ２０及び第２スペーサ２２とが接着することのない温度で施す。かかる加熱処理温度は、図５に示す矢印Ｂの温度よりも低温となるため、加熱時間を矢印Ｂの温度で施す場合よりも長くすることが好ましい。
【００１７】
以上、述べてきた図３及び図４においては、一枚の帯状金属製プレート１０を一対の第１スペーサ２０と第２スペーサ２２との間に挟み込んで平坦化処理を施したが、図６に示す様に、複数枚の帯状金属製プレート１０、１０・・の各々を一対の第１スペーサ２０と第２スペーサ２２との間に挟み込み積層して平坦化処理を施してもよい。
この様に、複数枚の帯状金属製プレート１０、１０・・を積層して平坦化処理する場合、図７に示す様に、一枚の帯状金属製プレート１０を挟み込んだ一対の第１スペーサ２０と第２スペーサ２２とを積層した後、最上部と最下部とに位置する第１スペーサ２０と第２スペーサ２２とに所定の力Ｆ１、Ｆ２を加えることによって、帯状金属製プレート１０の各々を一対の第１スペーサ２０と第２スペーサ２２とにより所定圧力で挟み込むことができる。
【００１８】
図７において、複数枚の帯状金属製プレート１０、１０・・を積層し、各凸部平坦面１２ａを平坦化処理する際に、図７（ａ）は、第１スペーサ２０の凹部底面２６ａと帯状金属製プレート１０の凸部平坦面１２ａとが当接したとき、第１スペーサ２０の凹部形成面２４と金属製プレート１０の凸部形成面１４との間のみにクリアランスを設ける例である。また、図７（ｂ）は、第１スペーサ２０の凹部形成面２４と金属製プレート１０の凸部形成面１４との間にクリアランスを設け、更に帯状金属製プレート１０の凹部１８の底面と第２スペーサ２２の凸部３０の上面とが当接したとき、帯状金属製プレート１０の凹部形成面１６と第２スペーサ２２の凸部形成面２８との間にクリアランスを設ける例である。
【００１９】
以上、述べてきた図１〜図７においては、帯状金属製プレート１０を一対の第１スペーサ２０と第２スペーサ２２との間に挟み込んで平坦化処理を施しているが、プレス加工で形成した帯状金属製プレート１０を、図１（ａ）に示す一点鎖線Ａの箇所で切断し、凸部１２が一個形成された個片とした後、この個片の金属製プレートを一対の第１スペーサ２０と第２スペーサ２２との間に挟み込んで平坦化処理を施してもよい。
【００２０】
【発明の効果】
本発明によれば、第１スペーサと第２スペーサとによって金属製プレートを挟み込んで平坦化処理を行う際に、半導体素子が搭載される金属製プレートの凸部に形成された凸部平坦面と第１スペーサの凹部底面とが、第１スペーサの凸部形成面と金属製プレートの凸部形成面との間にクリアランスを形成することによって確実に当接して平坦化処理が施される。
このため、金属製プレートの凸部の上面は確実に平坦度が向上される結果、平坦化処理が施された金属製プレートを半導体装置用放熱板に用いることによって、この放熱板の凸部の上面に搭載された半導体素子は、その背面が凸部の上面に密着でき、放熱性が向上された半導体装置を得ることができる。
また、従来、研削加工によって形成されていた半導体装置用放熱板をプレス加工によって形成可能となり、金属製の放熱板を使用した半導体装置の製造コストの低減を図ることも可能である。
【図面の簡単な説明】
【図１】本発明に係る半導体装置用放熱板を得ることができる帯状金属製プレートを説明する斜視図と横断面図である。
【図２】帯状金属製プレートと一対のスペーサとの関係を説明する横断面図である。
【図３】帯状金属製プレートを一対のスペーサによって挟み込んだ状態を説明する横断面図である。
【図４】帯状金属製プレートを一対のスペーサによって挟み込んだ他の状態を説明する横断面図である。
【図５】平坦化処理の加熱処理において採用する加熱処理温度について説明するグラフである。
【図６】複数枚の帯状金属製プレートに平坦化処理を施す際の金属製プレートの各々と一対のスペーサとの関係を説明する横断面図である。
【図７】複数枚の帯状金属製プレートの各々を一対のスペーサで挟み積層した状態を説明する横断面図である。
【図８】半導体装置の一例を説明する断面図である。
【図９】半導体装置の放熱板に使用される従来の金属製プレートの一例を説明する斜視図と横断面図である。
【符号の説明】
１０ 帯状金属製プレート
１２ 帯状金属製プレート１０の凸部
１２ａ 凸部１２の平坦面である上面
１４ 帯状金属製プレート１０の凸部形成面
１６ 帯状金属製プレート１０の凹部形成面
１８ 帯状金属製プレート１０の凹部
２０ 第１スペーサ
２２ 第２スペーサ
２４ 第１スペーサ２０の凹部形成面
２６ 第１スペーサ２０の凹部
２６ａ 第１スペーサ２０の凹部底面
２８ 第２スペーサ２２の凸部形成面
３０ 第２スペーサ２２の凸部
Ｆ１、Ｆ２ 力[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method of manufacturing a heat sink for a semiconductor device, and more specifically, a heat sink for a semiconductor device in which a semiconductor element is mounted on a flat surface formed on an upper surface of a convex portion protruding to one surface side of a metal plate. It relates to a manufacturing method.
[0002]
[Prior art]
The semiconductor device 100 includes a multilayer P-PGA (Multi Layer Plastic Pin Grid Array) type shown in FIG. In this semiconductor device 100, a plurality of pins 106, 106... Electrically connected to conductor patterns 104, 104... Formed between respective layers of a multilayer plastic substrate 102 are formed on the plastic substrate 102. The bottom surface of the cavity 108 is formed by a metal plate 110 made of copper, a copper alloy, or the like. A semiconductor element 112 is mounted on the flat surface of the convex portion 118 of the metal plate 104, and the mounted semiconductor element 112 is electrically connected to each of the conductor pattern 104 by bonding wires 114, 114.
Thus, by mounting the semiconductor element 112 on the metal plate 110, the heat dissipation of the semiconductor device 100 can be improved.
The semiconductor element 112 and the like mounted on the metal plate 110 are sealed by a cap 116 attached to the opening of the cavity 108.
[0003]
As shown in FIG. 9A, which is a perspective view of the metal plate 110, and FIG. 9B, which is a cross-sectional view in the YY plane, the semiconductor plate 112 is mounted in the vicinity of the central portion. A convex portion 118 having a surface formed on the upper surface is provided.
Since the upper surface 118a, which is a flat surface of the convex portion 118, requires extremely high flatness, conventionally, the convex portion 118 of the metal plate 110 has been formed by grinding.
[0004]
[Problems to be solved by the invention]
The metal plate 110 formed by grinding can finish the upper surface 118a of the convex portion 118 to a very high degree of flatness.
However, manufacturing the metal plate 110 by grinding increases the processing cost of the metal plate 110, so that the finally obtained semiconductor device is also expensive. Furthermore, the grinding process cannot easily improve the processing speed of the metal plate 110, and the production capacity tends to be limited.
For this reason, the present inventors have attempted a manufacturing method for manufacturing the metal plate 110 shown in FIG. 9 by cold forging (pressing), which can reduce the manufacturing cost as compared with the grinding process and has an excellent production capacity. . In this manufacturing method, the convex portion is formed by pressing from one side of the metal plate, but this manufacturing method is not preferable because the metal plate 110 extends in the outer peripheral direction.
On the other hand, according to the manufacturing method in which the concave portion is formed on one surface side of the metal plate by press working and the convex portion protrudes on the other surface side of the metal plate, extension of the metal plate 110 in the outer peripheral direction can be suppressed. However, in the metal plate 110 formed by such a manufacturing method, the flatness of the upper surface 118a of the convex portion 118 is inferior to the upper surface of the convex portion of the metal plate obtained by grinding. It turned out that it cannot be adopted as a board.
However, if the upper surface 118a of the convex portion 118 formed on the metal plate 110 by press working can be flattened, it is possible to supply a large amount of the metal plate 110 at a lower cost than the grinding processing at a low cost. is there.
Then, the subject of this invention can planarize the flat surface of the convex part of the metal plate obtained by pressing, suppressing the extension to the outer peripheral direction of a metal plate so that a semiconductor element can be mounted. It is providing the manufacturing method of the heat sink for semiconductor devices.
[0005]
[Means for Solving the Problems]
In order to solve the above problems, the present inventors first formed a metal plate by pressing a concave portion on one surface side of a metal plate and projecting the convex portion on the other surface side of the metal plate. The reason why the flatness of the upper surface of the formed convex part is inferior to that obtained by grinding was examined. The processing distortion due to the press work was inherent, and the press work was usually wound in a coil shape. Since a metal strip is used, it is considered that the obtained metal plate is caused by residual curl when wound in a coil shape.
For this reason, the present inventors have performed a flattening process while sandwiching a metal plate obtained by pressing using a pair of spacers following the uneven shape of each surface, so that the upper surface of the convex portion is highly enhanced. It has been found that a flattened metal plate can be obtained, and the present invention has been reached.
[0006]
That is, the present invention provides a method for manufacturing a heat sink for a semiconductor device in which a semiconductor element is mounted on a flat surface formed on the upper surface of a convex portion that protrudes to one surface of a metal plate. A concave portion is formed on the surface side by press working, and a convex portion corresponding to the concave portion is protruded to one surface side of the metal plate, and then the metal plate having the convex portion is formed on the convex portion of the metal plate. Between the first spacer in which the corresponding concave portion is formed and the second spacer in which the convex portion corresponding to the concave portion of the metal plate is formed, the bottom surface of the concave portion of the first spacer and the convex portion of the metal plate Between the first spacer and the concave portion forming surface of the metal plate and a convex portion forming surface of the metal plate, and then sandwiched by the first spacer and the second spacer. The In a method of manufacturing a semiconductor device for radiating plate, characterized in that flattening the upper surface of the convex portion of the metal plate genus plate made by subjecting a pressed while heating.
[0007]
In the present invention, the convex portion of the metal plate is preferably formed by cold forging, so that it is not necessary to consider the thermal shrinkage of the metal plate after press working as in warm forging.
Moreover, it is preferable that the clearance between the recessed part formation surface of a 1st spacer and the convex part formation surface of metal plates shall be 0.005-0.2 mm. Further, the convex portion forming surface of the second spacer and the concave portion forming surface of the metal plate are brought into contact with each other, and a clearance is also formed between the top surface of the convex portion of the second spacer and the bottom surface of the concave portion of the metal plate. Thereby, the flat surface of the recessed portion forming surface of the metal plate can also be achieved.
By using the first spacer and the second spacer made of the same metal as that of the metal plate, mutual correction of the first spacer, the second spacer, and the metal plate can be achieved. In this way, when using a metal spacer, the temperature of the heat treatment is set to a temperature that is lower than the softening point of the metal plate and does not adhere to the metal plate and the metal spacer. Therefore, adhesion between the two can be prevented.
Further, as a metal plate sandwiched between the first spacer and the second spacer, a plurality of recesses are formed in a row on the other surface side by pressing, and the protrusions corresponding to each of the recesses protrude to the one surface side. Using the strip-shaped metal plate, the heat treatment is performed while pressing the strip-shaped metal plate sandwiched between the first spacer and the second spacer, and then a predetermined portion between the convex portions of the strip-shaped metal plate is cut. By using individual metal plates, the production efficiency of the semiconductor device heat sink can be further improved.
[0008]
According to the present invention, when the metal plate on which the convex portion having a flat upper surface is formed by pressing is sandwiched between the first spacer and the second spacer, the upper surface of the convex portion of the metal plate is the first surface. When contacting the bottom surface of the recess formed in one spacer, a clearance is formed between the recess formation surface of the first spacer and the projection formation surface of the metal plate. For this reason, the concave portion forming surface of the first spacer and the convex portion forming surface of the metal plate abut before the upper surface of the convex portion of the metal plate contacts the bottom surface of the concave portion formed in the first spacer. Can be prevented.
Therefore, the upper surface of the convex portion of the metal plate is sandwiched at a predetermined pressure by the first spacer and the second spacer while being securely in contact with the bottom surface of the concave portion formed in the first spacer. Therefore, as a result of improving the flatness of the upper surface of the convex portion of the metal plate, the back surface of the semiconductor element can be reliably bonded to the upper surface of the convex portion.
[0009]
DETAILED DESCRIPTION OF THE INVENTION
As shown in FIG. 1A, a metal plate used as a heat sink for a semiconductor device according to the present invention has a flat upper surface along the longitudinal direction on one surface side 14 of a strip-shaped metal plate 10 made of aluminum. Are formed in a line, and then cut at a predetermined location between the convex portions 12 [location indicated by a one-dot chain line A in FIG. 1A].
The convex portions 12, 12,... Of the strip-shaped metal plate 10 are formed by cold forging (pressing). In this press work, as shown in FIG. 1 (b) which is a cross section in the XX plane of FIG. 1 (a), on the other side 16 of the strip-shaped metal plate 10 cut to a predetermined length, When the concave portion 18 is formed by press working, a portion of the one surface side 14 corresponding to the concave portion 18 protrudes to form the convex portion 12.
In this press working, it is preferable to form the concave portion 18 so that the opening area of the concave portion 18 is slightly smaller than the protruding area of the convex portion 12.
[0010]
Such a strip-shaped metal plate 10 is left with various residual stresses such as processing strain due to press working, and the flatness of the strip-shaped metal plate 10 is not sufficient, and the convex portion 12 which is a flat surface is formed. A semiconductor element cannot be mounted on the upper surface 12a (hereinafter sometimes referred to as the convex flat surface 12a).
This residual stress includes a coiled wrinkle attached to an aluminum plate that is a raw material of the strip-shaped metal plate 10. In other words, the aluminum plate is usually cut out from a metal strip wound in a coil shape and used for press working in a state where the coiled curl remains.
[0011]
In order to remove the residual stress and improve the flatness of the convex flat surface 12a, it is possible to perform a flattening process in which the convex flat surface 12a of the metal plate 10 is heated in a restrained state.
The strip-shaped metal plate 10 shown in FIG. 1 is convex on one side 14 (hereinafter may be referred to as a convex forming surface 14) and on the other side 16 (hereinafter may be referred to as a concave forming surface 16). Irregularities such as the portion 12 and the concave portion 18 are formed. Therefore, as shown in FIG. 2, a pair of first spacers 20 and second spacers 22 whose front side or back side is formed following the shape of the convex portion forming surface 14 or the concave portion forming surface 16 of the strip-shaped metal plate 10. And sandwiching the band-shaped metal plate 10 between the first spacer 20 and the second spacer 22, the flat surface 12 a of the band-shaped metal plate 10 can be easily flattened.
The pair of first spacers 20 and second spacers 22 are substantially the same size as the band-shaped metal plate 10, and the first spacers 20 attached to the convex portion forming surface 14 side of the band-shaped metal plate 10 are: The front surface side 32 is formed as a flat surface, but on the back surface side 24 (hereinafter sometimes referred to as the concave portion forming surface 24) corresponding to the convex portion forming surface 14 of the metal plate 10, A concave portion 26 into which the convex portion 12 formed on the ten convex portion forming surfaces 14 is inserted is formed.
On the other hand, the second spacer 22 mounted on the recess-forming surface 16 of the strip-shaped metal plate 10 has a back surface 34 formed on a flat surface, but the surface corresponding to the recess-forming surface 16 of the strip-shaped metal plate 10. On the side 28 (hereinafter sometimes referred to as the convex portion forming surface 28), a convex portion 30 is formed which is inserted into the concave portion 18 formed on the concave portion forming surface 16 of the belt-shaped metal plate 10.
[0012]
By attaching each of the pair of first spacers 20 and the second spacers 22 to a predetermined surface of the strip-shaped metal plate 10, as shown in FIG. 3, the pair of the first spacers 20 and the second spacers 22 and Can sandwich the band-shaped metal plate 10.
At this time, it is important that the bottom surface 26a of the recess 26 formed in the first spacer 20 (hereinafter sometimes referred to as the recess bottom surface 26a) and the convex flat surface 12a of the strip-shaped metal plate 10 are brought into contact with each other. . Even if the flattening process described later is performed without bringing the concave bottom surface 26a of the first spacer 20 into contact with the convex flat surface 12a of the strip metal plate 10, the convex flat surface 12a of the strip metal plate 10 is applied. Cannot be made sufficiently flat.
Here, in order to make the concave bottom surface 26a of the first spacer 20 and the convex flat surface 12a of the strip-shaped metal plate 10 abut reliably, as shown in FIG. 3, the concave bottom surface 26a of the first spacer 20 When the convex flat surface 12 a of the strip-shaped metal plate 10 comes into contact, a clearance t 1 is provided between the concave portion forming surface 24 of the first spacer 20 and the convex portion forming surface 14 of the metal plate 10. By providing the clearance t 1 , the contact between the concave bottom surface 26 a of the first spacer 20 and the convex flat surface 12 a of the strip metal plate 10 depends on the processing accuracy of the first spacer 20 and the strip metal plate 10. Prior to this, it is possible to avoid a situation in which the concave portion forming surface 24 of the first spacer 20 and the convex portion forming surface 14 of the strip-shaped metal plate 10 come into contact with each other.
[0013]
On the other hand, when there is no plan to attach a radiation fin or the like to the back surface (surface opposite to the surface on which the semiconductor element is mounted) of the semiconductor device heat radiation plate obtained by cutting the strip-shaped metal plate 10 Strict flatness is not required for either the concave portion forming surface 16 of the strip-shaped metal plate 10 or the bottom surface of the concave portion 18 which becomes the back surface of the heat sink for the semiconductor device, and the strip-shaped metal plate 10 and the second spacer 22 are formed. It is not necessary to provide a clearance at any location of both when abutting.
However, when flatness of the recess forming surface 16 of the belt-shaped metal plate 10 is required in order to mount the heat radiating fins, etc., as shown in FIG. When the convex portion forming surface 28 of the two spacers 22 abuts, a clearance t 2 is formed between the bottom surface of the concave portion 18 of the strip-shaped metal plate 10 and the top surface of the convex portion 30 of the second spacer 22, and the strip-shaped metal It is preferable that the concave portion forming surface 16 of the plate 10 and the convex portion forming surface 28 of the second spacer 22 are reliably brought into contact with each other.
In addition, when attaching a radiation fin etc. to the recessed part 18 formed in the back surface of the heat sink for semiconductor devices, the recessed part formation surface 16 of the strip | belt-shaped metal plate 10 and the convex part formation surface 28 of the 2nd spacer 22 exist. When contacted, a clearance t 2 is formed between the bottom surface of the concave portion 18 of the strip-shaped metal plate 10 and the top surface which is the flat surface of the convex portion 30 of the second spacer 22, and the concave portion forming surface of the strip-shaped metal plate 10 is formed. 16 and the convex forming surface 28 of the second spacer 22 can be reliably brought into contact with each other.
[0014]
In the present invention, as shown in FIG. 3 or FIG. 4, the pair of first spacers 20 and the second spacers 22 sandwich the strip-shaped metal plate 10, and a pair of first spacers corresponding to both surfaces of the strip-shaped metal plate 10. By applying forces F1 and F2 to the front surface 32 and the rear surface 34, which are flat surfaces of the spacer 20 and the second spacer 22, the band-shaped metal plate 10 can be sandwiched with a predetermined pressure.
Furthermore, in the present invention, as shown in FIG. 3 or FIG. 4, the band-shaped metal plate 10 is flattened while being sandwiched between the pair of first spacers 20 and second spacers 22 at a predetermined pressure.
In this flattening process, the belt-shaped metal plate 10 is subjected to a heat treatment and then a cooling process. First, in the heat treatment, in a graph showing the relationship between Rockwell hardness of the strip-shaped metal plate 10 shown in FIG. 5 and (H R) and the temperature, the inflection point (softening indicated by the arrow B where H R sharply drops Point) It is preferable to hold at a temperature in the vicinity for a predetermined time. Since the temperature of the inflection point (softening point) varies depending on the type of metal, it is preferable to investigate in advance the metal forming the strip-shaped metal plate 10 to be flattened.
This heat treatment is preferably performed in a non-oxidizing atmosphere such as a nitrogen atmosphere or a vacuum when the strip-shaped metal plate 10 is made of a metal that is easily oxidized.
Here, when the strip-shaped metal plate 10 is made of aluminum, the metal plate 10 is sandwiched between the pair of spacers 20 and 22 with a force of 0.5 to 1.0 kg / cm 2 , and is 1 at 200 to 300 ° C. It is preferable to perform a heat treatment for up to 2 hours.
[0015]
After performing this heat treatment, the metal plate 10 is subjected to a cooling treatment while being sandwiched between the pair of first spacers 20 and second spacers 22. In this cooling process, the band-shaped metal plate 10 sandwiched between the pair of first spacers 20 and second spacers 22 is controlled in a cooling atmosphere controlled so that the ambient temperature gradually decreases from the heating atmosphere such as a heating furnace. May be allowed to pass through and may be cooled, or may be taken out from the heating atmosphere to room temperature and allowed to cool.
By taking out the strip-shaped metal plate 10 from between the pair of first spacers 20 and second spacers 22 cooled to near room temperature, the strip-shaped metal plate 10 in which the flatness of the convex flat surface 12a and the like is remarkably improved. Can be obtained. For this reason, by cutting the obtained band-shaped metal plate 10 at a predetermined location between the convex portions 12 [location shown by a one-dot chain line A in FIG. 1A], a heat sink for a semiconductor device can be obtained. . The convex flat surface 12a formed on the upper surface of the convex portion 12 of the heat radiating plate has remarkably improved flatness, and can mount a semiconductor element.
Further, as shown in FIG. 4, the belt-shaped metal plate 10 is formed by planarizing the concave-shaped surface 16 of the strip-shaped metal plate 10 and the convex-shaped surface 28 of the second spacer 22. The semiconductor device heat sink can remarkably improve the flatness of the convex flat surface 12a on which the semiconductor elements are mounted and the concave portion forming surface 16 on which the heat radiating fins are mounted.
Here, when the strip-shaped metal plate 10 is taken out from between the pair of the first spacer 20 and the second spacer 22 during the cooling process, the unevenness due to the heat shrinkage of the strip-shaped metal plate 10 is made of the strip-shaped metal. It tends to occur on the convex flat surface 12 a and the concave forming surface 16 of the plate 10.
[0016]
As described above, the pair of first spacers 20 and the second spacers 22 that perform the flattening process with the band-shaped metal plate 10 sandwiched therebetween have a remarkably softening point temperature as compared with the band-shaped metal plate 10 such as ceramic or tungsten carbide. Although it may be formed of a high material, a pair of first spacers 20 and second spacers 22 formed of the same metal as the strip-shaped metal plate 10 to be planarized are used. Preferably, the spacer 20, the second spacer 22, and the strip metal plate 10 can be mutually corrected.
However, in this case, in the heat treatment, in order to prevent adhesion between the strip-shaped metal plate 10 and the first spacer 20 and the second spacer 22, the strip-shaped metal is lower than the softening point temperature of the strip-shaped metal plate 10. The plate 10 is applied at a temperature at which the pair of first spacers 20 and the second spacers 22 do not adhere to each other. Since this heat treatment temperature is lower than the temperature indicated by the arrow B shown in FIG.
[0017]
In FIG. 3 and FIG. 4 described above, a single band-shaped metal plate 10 is sandwiched between a pair of first spacers 20 and second spacers 22 and planarization is performed. As shown, each of the plurality of strip-shaped metal plates 10, 10... May be sandwiched and laminated between a pair of first spacers 20 and second spacers 22 for planarization.
When a plurality of strip metal plates 10, 10,... Are laminated and planarized in this way, a pair of first spacers 20 sandwiching one strip metal plate 10 as shown in FIG. And the second spacer 22 are stacked, and then each of the strip-shaped metal plates 10 is applied by applying predetermined forces F1 and F2 to the first spacer 20 and the second spacer 22 located at the uppermost part and the lowermost part. The pair of first spacers 20 and second spacers 22 can be sandwiched at a predetermined pressure.
[0018]
7, when a plurality of strip-shaped metal plates 10, 10... Are stacked and each convex flat surface 12a is flattened, FIG. 7 (a) shows the concave bottom surface 26a of the first spacer 20 and This is an example in which a clearance is provided only between the concave portion forming surface 24 of the first spacer 20 and the convex portion forming surface 14 of the metal plate 10 when the convex flat surface 12a of the belt-shaped metal plate 10 abuts. FIG. 7B shows a clearance between the concave portion forming surface 24 of the first spacer 20 and the convex portion forming surface 14 of the metal plate 10, and the bottom surface of the concave portion 18 of the band-shaped metal plate 10 and the This is an example in which a clearance is provided between the concave portion forming surface 16 of the belt-shaped metal plate 10 and the convex portion forming surface 28 of the second spacer 22 when the upper surface of the convex portion 30 of the two spacers 22 abuts.
[0019]
As described above, in FIG. 1 to FIG. 7, the band-shaped metal plate 10 is sandwiched between the pair of first spacers 20 and the second spacers 22 to perform the flattening process, but is formed by pressing. After the strip-shaped metal plate 10 is cut at a position indicated by a one-dot chain line A shown in FIG. 1A to form a piece having one protrusion 12 formed, the piece of the metal plate is used as a pair of first spacers. A planarization process may be performed by sandwiching between 20 and the second spacer 22.
[0020]
【The invention's effect】
According to the present invention, when the metal plate is sandwiched between the first spacer and the second spacer and the planarization process is performed, the convex flat surface formed on the convex portion of the metal plate on which the semiconductor element is mounted; The bottom surface of the concave portion of the first spacer is brought into contact with the surface by forming a clearance between the convex portion forming surface of the first spacer and the convex portion forming surface of the metal plate, so that the flattening process is performed.
For this reason, the flatness of the upper surface of the convex portion of the metal plate is reliably improved. As a result, by using the metal plate that has been subjected to the flattening process as the heat sink for the semiconductor device, The semiconductor element mounted on the upper surface can be closely adhered to the upper surface of the convex portion of the semiconductor element, and a semiconductor device with improved heat dissipation can be obtained.
Further, a heat sink for a semiconductor device that has been conventionally formed by grinding can be formed by press working, and it is possible to reduce the manufacturing cost of a semiconductor device using a metal heat sink.
[Brief description of the drawings]
1A and 1B are a perspective view and a cross-sectional view illustrating a belt-shaped metal plate from which a heat sink for a semiconductor device according to the present invention can be obtained.
FIG. 2 is a cross-sectional view illustrating the relationship between a belt-shaped metal plate and a pair of spacers.
FIG. 3 is a cross-sectional view illustrating a state in which a belt-shaped metal plate is sandwiched between a pair of spacers.
FIG. 4 is a cross-sectional view illustrating another state in which a belt-shaped metal plate is sandwiched between a pair of spacers.
FIG. 5 is a graph for explaining a heat treatment temperature employed in the heat treatment of the flattening treatment.
FIG. 6 is a cross-sectional view illustrating the relationship between each metal plate and a pair of spacers when a plurality of strip-shaped metal plates are flattened.
FIG. 7 is a cross-sectional view illustrating a state in which each of a plurality of strip-shaped metal plates is sandwiched and stacked between a pair of spacers.
FIG. 8 is a cross-sectional view illustrating an example of a semiconductor device.
FIGS. 9A and 9B are a perspective view and a cross-sectional view illustrating an example of a conventional metal plate used for a heat sink of a semiconductor device. FIGS.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 10 Strip | belt-shaped metal plate 12 Convex part 12a of the strip | belt-shaped metal plate 10 The upper surface 14 which is a flat surface of the convex part 12 The convex-part formation surface 16 of the strip | belt-shaped metal plate 10 The concave-part formation surface 18 of the strip | belt-shaped metal plate 10 10 concave portions 20 first spacer 22 second spacer 24 concave portion forming surface 26 of first spacer 20 concave portion 26a of first spacer 20 concave portion bottom surface 28 of first spacer 20 convex portion forming surface 30 of second spacer 22 second spacer 22 Convex part F1, F2 force

Claims (7)

金属製プレートの一面側に突出する凸部の上面に形成された平坦面に、半導体素子が搭載される半導体装置用放熱板を製造する際に、
該金属製プレートの他面側に凹部をプレス加工によって形成し、前記凹部に対応する凸部を金属製プレートの一面側に突出させた後、
前記凸部を形成した金属製プレートを、前記金属製プレートの凸部に対応する凹部が形成された第１スペーサと、前記金属製プレートの凹部に対応する凸部が形成された第２スペーサとの間に、前記第１スペーサの凹部の底面と金属製プレートの凸部の上面とを当接させると共に、前記第１スペーサの凹部形成面と金属製プレートの凸部形成面との間にクリアランスを設けて挟み込み、
次いで、前記第１スペーサと第２スペーサとによって挟み込まれた金属製プレートを加圧しつつ加熱処理を施して前記金属製プレートの凸部の上面を平坦化することを特徴とする半導体装置用放熱板の製造方法。When manufacturing a heat sink for a semiconductor device on which a semiconductor element is mounted on a flat surface formed on the upper surface of a convex portion protruding to one surface side of a metal plate,
After forming a concave portion on the other surface side of the metal plate by press working and projecting a convex portion corresponding to the concave portion to one surface side of the metal plate,
A metal plate having the convex portion, a first spacer having a concave portion corresponding to the convex portion of the metal plate, and a second spacer having a convex portion corresponding to the concave portion of the metal plate, Between the bottom surface of the concave portion of the first spacer and the top surface of the convex portion of the metal plate, and a clearance between the concave portion forming surface of the first spacer and the convex portion forming surface of the metal plate. And sandwiched,
Next, the metal plate sandwiched between the first spacer and the second spacer is subjected to heat treatment while pressurizing the metal plate to flatten the upper surface of the convex portion of the metal plate. Manufacturing method. 金属製プレートの凸部を、冷間鍛造によって形成する請求項１記載の半導体装置用放熱板の製造方法。The manufacturing method of the heat sink for semiconductor devices of Claim 1 which forms the convex part of metal plates by cold forging. 第１スペーサの凹部形成面と金属製プレートの凸部形成面との間のクリアランスを０．００５〜０．２ｍｍとする請求項１又は請求項２記載の半導体装置用放熱板の製造方法。The manufacturing method of the heat sink for semiconductor devices of Claim 1 or Claim 2 which makes the clearance between the recessed part formation surface of a 1st spacer, and the convex part formation surface of metal plates into 0.005-0.2 mm. 加熱処理の温度を、金属製プレートの軟化点よりも低温であって、前記金属製プレートと金属製スペーサとが接着することのない温度とする請求項１又は請求項２記載の半導体装置用放熱板の製造方法。3. The heat dissipation for a semiconductor device according to claim 1, wherein the temperature of the heat treatment is a temperature that is lower than a softening point of the metal plate and does not adhere the metal plate and the metal spacer. A manufacturing method of a board. 第１スペーサと第２スペーサとを、金属製プレートと同一金属によって形成された金属製のスペーサを用いる請求項１〜４のいずれか一項記載の半導体装置用放熱板の製造方法。The manufacturing method of the heat sink for semiconductor devices as described in any one of Claims 1-4 using the metal spacer formed by the same metal as a metal plate for a 1st spacer and a 2nd spacer. 第２スペーサの凸部形成面と金属製プレートの凹部形成面とを当接すると共に、前記第２スペーサの凸部の上面と金属製プレートの凹部の底面との間にクリアランスを形成する請求項１〜５のいずれか一項記載の半導体装置用放熱板の製造方法。2. The convex portion forming surface of the second spacer and the concave portion forming surface of the metal plate are brought into contact with each other, and a clearance is formed between the upper surface of the convex portion of the second spacer and the bottom surface of the concave portion of the metal plate. The manufacturing method of the heat sink for semiconductor devices as described in any one of -5. 第１スペーサと第２スペーサとの間に挟み込む金属製プレートとして、他面側に複数個の凹部をプレス加工によって一列に形成し、前記凹部の各々に対応する凸部を一面側に突出させた帯状金属製プレートを用い、前記第１スペーサと第２スペーサとによって挟み込まれた前記帯状金属製プレートを加圧しつつ加熱処理した後、前記帯状金属製プレートの凸部間の所定箇所を切断して個片の金属製プレートとする請求項１〜６のいずれか一項記載の半導体装置用放熱板の製造方法。As a metal plate sandwiched between the first spacer and the second spacer, a plurality of concave portions are formed in a row on the other surface side by press working, and the convex portions corresponding to each of the concave portions are projected to the one surface side. After using a strip metal plate and heat-treating the strip metal plate sandwiched between the first spacer and the second spacer while cutting, predetermined portions between the convex portions of the strip metal plate are cut. The manufacturing method of the heat sink for semiconductor devices as described in any one of Claims 1-6 used as an individual metal plate.
JP35108497A 1997-12-19 1997-12-19 Manufacturing method of heat sink for semiconductor device Expired - Fee Related JP3886626B2 (en)

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