JP4331830B2

JP4331830B2 - Ceramic circuit board

Info

Publication number: JP4331830B2
Application number: JP23688099A
Authority: JP
Inventors: 健古桑
Original assignee: Kyocera Corp
Current assignee: Kyocera Corp
Priority date: 1999-08-24
Filing date: 1999-08-24
Publication date: 2009-09-16
Anticipated expiration: 2019-08-24
Also published as: JP2001068808A

Description

【０００１】
【発明の属する技術分野】
本発明は、セラミック基板の両面に金属回路板を取着したセラミック回路基板に関するものである。
【０００２】
【従来の技術】
近年、パワーモジュール用基板やスイッチングモジュール用基板等の回路基板として、セラミック基板上に被着させたメタライズ金属層に銀−銅合金等のロウ材を介して銅等から成る金属回路板を接合させたセラミック回路基板、セラミック基板上に銀−銅共晶合金にチタン、ジルコニウム、ハフニウムあるいはその水素化物を添加した活性金属ロウ材を介して銅等から成る金属回路板を直接接合させたセラミック回路基板、或いは、セラミック基板上に銅板を載置させた後加熱し直接セラミック基板と銅板とを接合させた所謂、ＤＢＣ（ＤｉｒｅｃｔＢｏｎｄＣｏｐｐｅｒ）法によって作製されたセラミック回路基板が用いられている。
【０００３】
また、これら各セラミック回路基板は金属回路板の実装密度を高めるためにセラミック基板の上下両面に金属回路板を接合させておき、これら上下両面の金属回路板間をセラミック基板に設けた貫通孔内に充填されているロウ材で電気的に接続することが行われている。
【０００４】
なお、前記セラミック回路基板、例えば、セラミック基板上に被着させたメタライズ金属層にロウ材を介して銅等から成る金属回路板を接合させたセラミック回路基板は、一般に酸化アルミニウム質焼結体、窒化アルミニウム質焼結体、窒化珪素質焼結体、ムライト質焼結体等の電気絶縁性のセラミックス材料から成り、上下両面に所定パターンのメタライズ金属層を有し、かつ厚み方向に貫通する貫通孔を設けたセラミック基板を準備し、次に前記セラミック基板の貫通孔内に、銀ロウ粉末（銀と銅の合金粉末）に有機溶剤、溶媒を添加混合して得たロウ材ペーストを充填するとともにメタライズ金属層上に間に銀ロウ等のロウ材を挟んで所定パターンの金属回路板を載置当接させ、しかる後、これを還元雰囲気中、約９００℃の温度に加熱し、ロウ材ペースト及びロウ材を溶融させ、メタライズ金属層と金属回路板及びセラミック基板の上下両面の金属回路板をおのおの銀ロウ等のロウ材を介し接合することによって製作される。
【０００５】
【発明が解決しようとする課題】
しかしながら、この従来のセラミック回路基板においては、セラミック基板の上下両面に接合されている金属回路板同士がセラミック基板に設けた貫通孔内に充填されているロウ材を介して電気的に接続されており、該セラミック基板に設けた貫通孔内へのロウ材の充填はセラミック基板の貫通孔内に銀ロウ粉末（銀と銅の合金粉末）に有機溶剤、溶媒を添加混合して得たロウ材ペーストを充填させた後、約９００℃の温度に加熱することによって行われ、この場合、各銀ロウ粉末間に存在する空気が溶融した銀ロウ材中に多量に抱き込まれて多孔質となり、導通抵抗が比抵抗で７〜１０μΩｃｍと高いものであった。そのため従来のセラミック回路基板では金属回路板及び貫通孔内のロウ材に１０Ａを超える大電流が流れると貫通孔内に充填されたロウ材部分が抵抗発熱し、その熱が金属回路板上に半田等の接着材を介して接着固定される半導体素子等の電子部品に作用し、電子部品を高温として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。
【０００６】
本発明は上記欠点に鑑み案出されたもので、その目的は抵抗発熱による多量の熱の発生を有効に防止し、金属回路板に接続される半導体素子等の電子部品を常に適温として正常、かつ安定に作動させることができるセラミック回路基板を提供することにある。
【０００７】
【課題を解決するための手段】
本発明のセラミック回路基板は、貫通孔を有するセラミック基板の両面に前記貫通孔を塞ぐように金属回路板を取着させるとともに前記貫通孔内に比抵抗が４μΩｃｍ以下の金属材から成る金属柱を、両端が前記金属回路板に接触した状態で配置させ、前記金属柱で前記セラミック基板両面の前記金属回路板を接続したことを特徴とするものである。
【０００８】
本発明のセラミック回路基板によれば、セラミック基板の両面に取着されている金属回路板を、セラミック基板の貫通孔内に配置されている気孔がほとんどなく、比抵抗が４μΩｃｍ以下の金属柱を、両端が金属回路板に接触した状態で配置させ、この金属柱で電気的に接続したことから、金属回路板及び金属柱に１０Ａを超える大電流が流れたとしても金属柱で抵抗発熱が起こり、多量の熱を発生することは無く、その結果、金属回路板上に半田等の接着材を用いて接着固定される半導体素子等の電子部品は常に適温となり、長期間にわたって正常、かつ安定に作動させることが可能となる。
【０００９】
【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は、本発明のセラミック回路基板の一実施例を示し、１はセラミック基板、２はメタライズ金属層、３は金属回路板である。
【００１０】
前記セラミック基板１は四角形状をなし、一部に厚み方向に貫通する貫通孔４が形成されており、該貫通孔４内には金属柱５が挿着されている。
【００１１】
また前記セラミック基板１はその上下両面にメタライズ金属層２が被着されており、該メタライズ金属層２には金属回路板３がロウ付けされている。
【００１２】
前記セラミック基板１は酸化アルミニウム質焼結体、ムライト質焼結体、炭化珪素質焼結体、窒化アルミニウム質焼結体、窒化珪素質燒結体等の電気絶縁材料から成り、例えば、酸化アルミニウム質焼結体から成る場合には、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、可塑剤、溶剤を添加混合して泥漿状となすとともに該泥漿物を従来周知の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）を形成し、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し、貫通孔４となる孔を有する所定形状に成形するとともに高温（約１６００℃）で焼成することによって、あるいは酸化アルミニウム等の原料粉末に適当な有機溶剤、溶媒を添加混合して原料粉末を調整するとともに該原料粉末をプレス成形機によって貫通孔４となる孔を有した所定形状に形成し、しかる後、前記形成体を約１６００℃の温度で焼成することによって製作される。
【００１３】
前記セラミック基板１は金属回路板３を支持する支持部材として作用し、その上下両面及び貫通孔４内壁面にメタライズ金属層２が所定パターンに被着形成されており、該セラミック基板１の上下両面に被着されているメタライズ金属層２には所定パターンの金属回路板３がロウ付けされている。
【００１４】
前記メタライズ金属層２は金属回路板３をセラミック基板１にロウ付けする際の下地金属層として作用し、タングステン、モリブデン、マンガン等の高融点金属材料より成り、例えば、タングステン粉末に適当な有機バインダー、可塑材、溶剤を添加混合して得た金属ペーストを焼成によってセラミック基板１となるセラミックグリーンシート（セラミック生シート）の上下両面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印刷塗布しておくことによってセラミック基板１の上下両面に所定パターン、所定厚み（１０〜５０μｍ）に被着される。
【００１５】
なお、前記メタライズ金属層２はその表面にニッケル、金等の良導電性で、耐蝕性及びロウ材との濡れ性が良好な金属をメッキ法により１μｍ〜２０μｍの厚みに被着させておくと、メタライズ金属層２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金属層２と金属回路板３とのロウ付けを極めて強固となすことができる。従って、前記メタライズ金属層２の酸化腐蝕を有効に防止し、メタライズ金属層２と金属回路板３とのロウ付けを強固となすにはメタライズ金属層２の表面にニッケル、金等の良導電性で、耐蝕性及びロウ材との濡れ性が良好な金属を１μｍ〜２０μｍの厚みに被着させておくことが好ましい。
【００１６】
前記セラミック基板１の上下両面に被着されているメタライズ金属層２には金属回路板３がセラミック基板１に設けた貫通孔４を塞ぐようにしてロウ材を介し取着されている。
【００１７】
前記金属回路板３は銅やアルミニウム等の金属材料から成り、セラミック基板１の上下両面に被着形成されているメタライズ金属層２上に銀ロウ等のロウ材を介して取着される。
【００１８】
なお、前記銅やアルミニウム等から成る金属回路板３は、銅やアルミニウム等のインゴット（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、例えば、厚さが５００μｍで、メタライズ金属層２のパターン形状に対応する所定パターン形状に形成される。
【００１９】
また、前記金属回路板３はこれを無酸素銅で形成しておくと、該無酸素銅はロウ付けの際に銅の表面が銅中に存在する酸素により酸化されることなくロウ材との濡れ性が良好となり、メタライズ金属層２へのロウ材を介しての接合が強固となる。従って、前記金属回路板３はこれを無酸素銅で形成しておくことが好ましい。
【００２０】
更に前記金属回路板３はその表面にニッケル等から成る、良導電性で、かつ耐蝕性及びロウ材との濡れ性が良好な金属をメッキ法により被着させておくと、金属回路板３に酸化腐蝕が発生するのを有効に防止することができるとともに金属回路板３と外部電気回路との電気的接続及び金属回路板３への半導体素子等の電子部品の接続を強固となすことができる。従って、前記金属回路板３はその表面にニッケル等から成る、良導電性で、かつ耐蝕性及びロウ材との濡れ性が良好な金属をメッキ法により被着させておくことが好ましい。
【００２１】
また更に、前記セラミック基板１に被着させたメタライズ金属層２への金属回路板３のロウ付けは、メタライズ金属層２上に金属回路板３を、間に、例えば、銀ロウ材（銀：７２重量％、銅：２８重量％）やアルミニウムロウ材（アルミニウム：８８重量％、シリコン：１２重量％）等から成るロウ材を挟んで載置させ、しかる後、金属回路板３に３０〜１００ｇ／ｃｍ²の荷重を加えた状態で真空中もしくは中性、還元雰囲気中、所定温度（銀ロウ材の場合は約９００℃、アルミニウムロウ材の場合は約６００℃）に加熱処理し、ロウ材を溶融せしめ、該溶融したロウ材でメタライズ金属層２と金属回路板３とを接合させることによって行われる。
【００２２】
前記金属回路板３がロウ付けされたセラミック基板１はまた貫通孔４の内部に金属柱５が配置されており、該金属柱５はセラミック基板１の上下両面にロウ付けされている金属回路板３間を電気的に接続する作用をなす。
【００２３】
前記金属柱５は比抵抗が４μΩｃｍ以下の銅（１．７μΩｃｍ）、アルミニウム（２．７μΩｃｍ）、銀（１．６μΩｃｍ）等の良導電性の金属材により形成されており、金属柱５の比抵抗が４μΩｃｍ以下と小さい、即ち、金属柱５の導通抵抗が小さいことから金属回路板３及び金属柱５に１０Ａを超える大電流が流れたとしても金属回路板３及び金属柱５より抵抗発熱により大量の熱が発生することは無く、その結果、金属回路板３上に半田等の接着材を用いて接着固定される半導体素子等の電子部品は常に適温となり、長期間にわたって正常、かつ安定に作動させることが可能となる。
【００２４】
前記金属柱５は、例えば、銅から成る場合、銅のインゴット（塊）に圧延加工法や打ち抜き加工法、引き抜き加工法等、従来周知の金属加工法を施すことによって円柱状に形成され、セラミック基板１に設けられた貫通孔４内に、両端をセラミック基板１の上下両面に取着されている金属回路板３に接触するように配置させるとともに貫通孔４内壁に被着されているメタライズ金属層２に銀ロウ等のロウ材を介しロウ付けすることによって、セラミック基板１の貫通孔４内に両端がセラミック基板１の上下両面に取着されている金属回路板３に接触した状態で配置される。
【００２５】
なお、前記金属柱５はこれを無酸素銅で形成しておくと、該無酸素銅はロウ付けの際に銅の表面が銅中に存在する酸素により酸化されることなくロウ材との濡れ性が良好となり、セラミック基板１の貫通孔４内壁に被着させたメタライズ金属層へのロウ材を介しての接合が強固となる。従って、前記金属柱５はこれを無酸素銅で形成しておくことが好ましい。
【００２６】
また前記金属柱５はその径が２００μｍ未満となると金属柱５の導通抵抗が大きくなって１０Ａを超える大電流が流れた場合に抵抗発熱により多量の熱が発生してしまう危険性がある。従って、前記金属柱５はその径を２００μｍ以上、好適には３５０μｍ以上としておくことがよい。特に金属柱５の径を３５０μｍ以上としておくと金属柱５に２０Ａを超える大電流が流れても抵抗発熱による多量の熱を発生することはなく、これによって金属回路板３上に半田等の接着材を用いて接着固定される半導体素子等の電子部品を常に適温となすことができ、電子部品を長期間にわたって正常、かつ安定に作動させることが可能となる。
【００２７】
かくして、上述のセラミック回路基板によれば、セラミック基板１の上面に取着された金属回路板３に半田等の接着材を介して半導体素子等の電子部品を接着固定させるとともに半導体素子等の電子部品の各電極をボンディングワイヤ等の電気的接続手段を介して金属回路板３に電気的に接続させれば半導体素子等の電子部品はセラミック回路基板に実装され、同時に金属回路板３を外部電気回路に電気的に接続させれば半導体素子等の電子部品は外部電気回路に接続されることとなる。
【００２８】
次に本発明の他の実施例を図２及び図３に基づいて説明する。
なお、図中、図１と同一個所については同一符号が付してある。
図２のセラミック回路基板は、セラミック基板１の上下両面に所定パターンの金属回路板３が活性金属ロウ材６を介して取着されており、同時にセラミック基板１に設けた厚み方向に貫通する貫通孔４内に金属柱５がその外表面を活性金属ロウ材６を介し貫通孔４内壁に取着することによって配置されている。
【００２９】
前記セラミック基板１に設けた貫通孔４内に配置されている金属柱５はその両端が金属回路板３に接触しており、これによってセラミック基板１の上下両面に取着されている金属回路板３は金属柱５を介して電気的に接続されることとなる。
【００３０】
前記貫通孔４を有するセラミック基板１は上述の実施例と同様の材料からなり、同様の方法によって所定形状に作成されている。
【００３１】
また前記セラミック基板１はその上下両面でセラミック基板１に設けた貫通孔４を塞ぐように金属回路板３が活性金属ロウ材６を介して取着されており、該金属回路板３は銅やアルミニウム等の金属材料から成り、銅やアルミニウム等のインゴット（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、例えば、５００μｍの厚みで、所定のパターンに形成される。
【００３２】
なお、前記金属回路板３はこれを無酸素銅で形成しておくと、該無酸素銅は活性金属ロウ材６を介して取着する際、銅の表面が銅中に存在する酸素により酸化されることなく活性金属ロウ材６との濡れ性が良好となって金属回路板３をセラミック基板１に活性金属ロウ材６を介しての取着接合が強固となる。従って、前記金属回路板３はこれを無酸素銅で形成しておくことが好ましい。
【００３３】
また前記セラミック基板１は貫通孔４の内部に金属柱５が配置されており、該金属柱５はセラミック基板１の上下両面にロウ付けされている金属回路板３間を電気的に接続する作用をなす。
【００３４】
前記金属柱５は比抵抗が４μΩｃｍ以下の銅（１．７μΩｃｍ）、アルミニウム（２．７μΩｃｍ）、銀（１．６μΩｃｍ）等の良導電性の金属材により形成されており、金属柱５の比抵抗が４μΩｃｍ以下と小さい、即ち、金属柱５の導通抵抗が小さいことから金属回路板３及び金属柱５に１０Ａを超える大電流が流れたとしても金属回路板３及び金属柱５より抵抗発熱により大量の熱が発生することは無く、その結果、金属回路板３上に半田等の接着材を用いて接着固定される半導体素子等の電子部品は常に適温となり、長期間にわたって正常、かつ安定に作動させることが可能となる。
【００３５】
前記金属柱５は、例えば、銅から成る場合、銅のインゴット（塊）に圧延加工法や打ち抜き加工法、引き抜き加工法等、従来周知の金属加工法を施すことによって円柱状に形成され、セラミック基板１に設けられた貫通孔４内に、両端をセラミック基板１の上下両面に取着されている金属回路板３に接触するように配置させるとともに貫通孔４内壁に活性金属ロウ材６を介して取着される。
【００３６】
なお、前記金属柱５はこれを無酸素銅で形成しておくと、該無酸素銅は活性金属ロウ材６を介してセラミック基板１の貫通孔４内に取着する際、銅の表面が銅中に存在する酸素により酸化されることなく活性金属ロウ材６との濡れ性が良好となり、セラミック基板１の貫通孔４内壁に活性金属ロウ材６を介して強固に接合することとなる。従って、前記金属柱５はこれを無酸素銅で形成しておくことが好ましい。
【００３７】
また前記金属柱５はその径が２００μｍ未満となると金属柱５の導通抵抗が大きくなって１０Ａを超える大電流が流れた場合に抵抗発熱により多量の熱が発生してしまう危険性がある。従って、前記金属柱５はその径を２００μｍ以上、好適には３５０μｍ以上としておくことがよい。特に金属柱５の径を３５０μｍ以上としておくと金属柱５に２０Ａを超える大電流が流れても抵抗発熱による多量の熱を発生することはなく、これによって金属回路板３上に半田等の接着材を用いて接着固定される半導体素子等の電子部品を常に適温となすことができ、電子部品を長期間にわたって正常、かつ安定に作動させることが可能となる。
【００３８】
更に前記金属回路板３及び金属柱５は金属活性ロウ材を使用することによってメタライズ金属層を不要としてセラミック基板１の上下両面および貫通孔４内にロウ付け取着されており、該金属活性ロウ材としては金属回路板３及び金属柱５が銅で形成されている場合は銀−銅共晶合金にチタン、ジルコニウム、ハフニウム等の金属もしくはその水素化物を２〜５重量％添加させたものが、また金属回路板３及び金属柱５がアルミニウムで形成されている場合はアルミニウム−シリコン共晶合金にチタン、ジルコニウム、ハフニウム等の金属もしくはその水素化物を２〜５重量％添加させたものが好適に使用される。
【００３９】
前記金属活性ロウ材を使用しての金属回路板３及び金属柱５の貫通孔４を有するセラミック基板１への取着はまず、例えば、銀−銅共晶合金にチタン、ジルコニウム、ハフニウム等の金属もしくはその水素化物を２〜５重量％添加させたものに有機溶剤、溶媒を混合して活性金属ロウ材ペーストを作成し、次にセラミック基板１の上下両面及び貫通孔４内壁に前記活性金属ロウ材ペーストを従来周知のスクリーン印刷法等を採用することによって所定パターンに印刷塗布し、次に前記セラミック基板１の貫通孔４内に金属柱５を挿入配置させるとともにセラミック基板１の上下両面に印刷塗布されている活性金属ロウ材ペースト上に金属回路板３を載置させ、しかる後、これを真空中もしくは中性、還元雰囲気中、所定温度（銅の場合は約９００℃、アルミニウムの場合は約６００℃）で加熱処理し、活性金属ロウ材６を溶融せしめ、該溶融した活性金属ロウ材６でセラミック基板１と金属回路板３及び金属柱５とを接合させることによって行われる。
【００４０】
かかるセラミック回路基板は上述の実施例と同様、金属柱５の比抵抗が４μΩｃｍ以下と小さい、即ち、金属柱５の導通抵抗が小さいことから金属回路板３及び金属柱５に１０Ａを超える大電流が流れたとしても金属回路板３及び金属柱５より抵抗発熱により大量の熱が発生することは無く、その結果、金属回路板３上に半田等の接着材を用いて接着固定される半導体素子等の電子部品は常に適温となり、長期間にわたって正常、かつ安定に作動させることが可能となる。
【００４１】
また図３のセラミック回路基板は、セラミック基板１の上下両面に銅からなる所定パターンの金属回路板３がＤＢＣ（ＤｉｒｅｃｔＢｏｎｄＣｏｐｐｅｒ）法によって取着されており、同時にセラミック基板１に設けた厚み方向に貫通する貫通孔４内に金属柱５がその両端を金属回路板３に接触した状態で配置されている。
【００４２】
前記貫通孔４を有するセラミック基板１は前述の実施例と同様の材料からなり、同様の方法によって所定形状に作成されている。
【００４３】
前記セラミック基板１はその上下両面でセラミック基板１に設けた貫通孔４を塞ぐように銅からなる金属回路板３がＤＢＣ法によって取着されており、該銅からなる金属回路板３は銅のインゴット（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、例えば、５００μｍの厚みで、所定のパターンに形成される。
【００４４】
前記金属回路板３のセラミック基板１の上下両面への取着は、セラミック基板１の上下両面に金属回路板３をセラミック基板１に設けた貫通孔４を塞ぐように載置当接させ、次にこれを真空中もしくは中性、還元雰囲気中、所定温度（１０６５〜１０８３℃）で加熱処理し、セラミック基板１の上面と金属回路板３の下面との間に銅−酸化銅共晶を形成することによってセラミック基板１の表面に取着される。
【００４５】
なお、前記銅からなる金属回路板３はその表面に予め０．０２〜０．５μｍの酸化膜を形成しておく、あるいは酸素含有量を１００〜２０００ｐｐｍとしておくとセラミック基板１と金属回路板３とを接合する際、銅−酸化銅の共晶が容易となってセラミック基板１に金属回路板３を極めて強固に取着接合させることができる。従って、前記銅からなる金属回路板３はその表面に予め０．０２〜０．５μｍの酸化膜を形成しておく、あるいは酸素含有量を１００〜２０００ｐｐｍとしておくことが好ましい。
【００４６】
また前記銅からなる金属回路板３はその表面にニッケルから成る、良導電性で、かつ耐食性及びロウ材との濡れ性が良好な金属をメッキ法により被着させておくと、金属回路板３と半導体素子等の電子部品及び外部電気回路との電気的接続を良好と成すことができる。従って、前記銅からなる金属回路板３はその表面にニッケルから成る、良導電性で、かつ耐食性及びロウ材との濡れ性が良好な金属をメッキ法により被着させておくことが好ましい。
【００４７】
更に前記セラミック基板１は貫通孔４の内部に金属柱５が配置されており、該金属柱５はセラミック基板１の上下両面に取着されている金属回路板３間を電気的に接続する作用をなす。
【００４８】
前記金属柱５は比抵抗が４μΩｃｍ以下の銅（１．７μΩｃｍ）、アルミニウム（２．７μΩｃｍ）、銀（１．６μΩｃｍ）等の良導電性の金属材により形成されており、金属柱５の比抵抗が４μΩｃｍ以下と小さい、即ち、金属柱５の導通抵抗が小さいことから金属回路板３及び金属柱５に１０Ａを超える大電流が流れたとしても金属回路板３及び金属柱５より抵抗発熱により大量の熱が発生することは無く、その結果、金属回路板３上に半田等の接着材を用いて接着固定される半導体素子等の電子部品は常に適温となり、長期間にわたって正常、かつ安定に作動させることが可能となる。
【００４９】
なお、前記金属柱５は、例えば、銅から成る場合、銅のインゴット（塊）に圧延加工法や打ち抜き加工法、引き抜き加工法等、従来周知の金属加工法を施すことによって円柱状に形成され、セラミック基板１に設けられた貫通孔４内に挿入配置させ、セラミック基板１の上下両面に該セラミック基板１に設けた貫通孔４を塞ぐように銅からなる金属回路板３をＤＢＣ法により取着させることによって、両端をセラミック基板１の上下両面に取着される金属回路板３と接触するようにして貫通孔４内に配置される。
【００５０】
また前記金属柱５はその径が２００μｍ未満となると金属柱５の導通抵抗が大きくなって１０Ａを超える大電流が流れた場合に抵抗発熱により多量の熱が発生してしまう危険性がある。従って、前記金属柱５はその径を２００μｍ以上、好適には３５０μｍ以上としておくことがよい。特に金属柱５の径を３５０μｍ以上としておくと金属柱５に２０Ａを超える大電流が流れても抵抗発熱による多量の熱を発生することはなく、これによって金属回路板３上に半田等の接着材を用いて接着固定される半導体素子等の電子部品を常に適温となすことができ、電子部品を長期間にわたって正常、かつ安定に作動させることが可能となる。
【００５１】
更に本発明は上述の実施例に限定されるものではなく、本発明の趣旨を逸脱しない範囲であれば種々の変更は可能である。
【００５２】
【発明の効果】
本発明のセラミック回路基板によれば、セラミック基板の両面に取着されている金属回路板をセラミック基板の貫通孔内に配置されている気孔がほとんどなく、比抵抗が４μΩｃｍ以下の金属柱を、両端が金属回路板に接触した状態で配置させ、この金属柱で電気的に接続したことから、金属回路板及び金属柱に１０Ａを超える大電流が流れたとしても金属柱で抵抗発熱が起こり、多量の熱を発生することは無く、その結果、金属回路板上に半田等の接着材を用いて接着固定される半導体素子等の電子部品は常に適温となり、長期間にわたって正常、かつ安定に作動させることが可能となる。
【図面の簡単な説明】
【図１】本発明のセラミック回路基板の一実施例を示す断面図である。
【図２】本発明の他の実施例を示す断面図である。
【図３】本発明の他の実施例を示す断面図である。
【符号の説明】
１・・・・セラミック基板
２・・・・メタライズ金属層
３・・・・金属回路板
４・・・・貫通孔
５・・・・金属柱
６・・・・活性金属ロウ材[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a ceramic circuit board having metal circuit boards attached to both sides of the ceramic board.
[0002]
[Prior art]
In recent years, a metal circuit board made of copper or the like is bonded to a metallized metal layer deposited on a ceramic substrate through a brazing material such as a silver-copper alloy as a circuit board such as a power module board or a switching module board. Ceramic circuit board obtained by directly joining a metal circuit board made of copper or the like through an active metal brazing material in which titanium, zirconium, hafnium or a hydride thereof is added to a silver-copper eutectic alloy on the ceramic circuit board. Alternatively, a ceramic circuit substrate manufactured by a so-called DBC (Direct Bond Copper) method in which a copper plate is placed on a ceramic substrate and then heated to directly join the ceramic substrate and the copper plate is used.
[0003]
In addition, in order to increase the mounting density of the metal circuit boards, the ceramic circuit boards are bonded to the upper and lower surfaces of the ceramic board, and the space between the upper and lower metal circuit boards is within the through-hole provided in the ceramic board. Electrical connection is made with a brazing material filled in the metal.
[0004]
The ceramic circuit board, for example, a ceramic circuit board in which a metal circuit board made of copper or the like is bonded to a metallized metal layer deposited on the ceramic board via a brazing material is generally an aluminum oxide sintered body, It is made of an electrically insulating ceramic material such as an aluminum nitride sintered body, a silicon nitride sintered body, or a mullite sintered body, and has a metallized metal layer with a predetermined pattern on both upper and lower surfaces, and penetrates in the thickness direction. Prepare a ceramic substrate with holes, and then fill the through holes of the ceramic substrate with a brazing material paste obtained by adding and mixing an organic solvent and a solvent to silver brazing powder (alloy powder of silver and copper). At the same time, a metal circuit board having a predetermined pattern is placed on and abutted on the metallized metal layer with a brazing material such as silver solder interposed therebetween, and then this is heated to a temperature of about 900 ° C. in a reducing atmosphere. And the brazing material paste and brazing material is melted, it is fabricated by respectively bonding a brazing material of silver solder or the like metallized metal layer and the metal circuit plate and the upper and lower surfaces of the metal circuit plate of the ceramic substrate.
[0005]
[Problems to be solved by the invention]
However, in this conventional ceramic circuit board, the metal circuit boards bonded to the upper and lower surfaces of the ceramic board are electrically connected via a brazing material filled in a through hole provided in the ceramic board. In addition, the brazing material obtained by adding an organic solvent and a solvent to silver brazing powder (alloy powder of silver and copper) in the through hole of the ceramic substrate is filled in the through hole provided in the ceramic substrate. After filling the paste, it is performed by heating to a temperature of about 900 ° C. In this case, a large amount of air existing between the silver brazing powders is embraced in the molten silver brazing material and becomes porous, The conduction resistance was as high as 7 to 10 μΩcm in specific resistance. Therefore, in a conventional ceramic circuit board, when a large current exceeding 10 A flows through the metal circuit board and the brazing material in the through hole, the brazing material portion filled in the through hole generates resistance heat, and the heat is soldered on the metal circuit board. However, it has a drawback in that the electronic component cannot be stably operated at a high temperature by acting on an electronic component such as a semiconductor element that is bonded and fixed via an adhesive material such as the above.
[0006]
The present invention has been devised in view of the above-mentioned drawbacks, and its purpose is to effectively prevent the generation of a large amount of heat due to resistance heat generation, and to normally operate electronic components such as semiconductor elements connected to the metal circuit board as appropriate temperatures, It is another object of the present invention to provide a ceramic circuit board that can be stably operated.
[0007]
[Means for Solving the Problems]
Ceramic circuit board of the present invention, the metal columns consisting resistivity in the through-hole causes attached a metal circuit plate so as to close the through-hole on both surfaces of the ceramic substrate from the metallic material 4μΩcm having a through-hole , both ends were is placed in contact with the metal circuit plate, is characterized in that connects the metal circuit plate of the ceramic substrate both sides with the metal column.
[0008]
According to the ceramic circuit board of the present invention, a metal circuit plate which is attached to both surfaces of the ceramic substrate, almost no pores disposed in the through hole of the ceramic substrate, specific resistance of the following metal columns 4μΩcm , it is disposed in a state in which both ends are in contact with the metal circuit plate, since the electrically connected with the metal columns, also occurs the resistance heating in the metal column as a large current of more than 10A on the metal circuit plate and the metal column flows As a result, a large amount of heat is not generated, and as a result, electronic components such as semiconductor elements that are bonded and fixed onto a metal circuit board using an adhesive such as solder are always at an appropriate temperature, and are normal and stable over a long period of time. It can be activated.
[0009]
DETAILED DESCRIPTION OF THE INVENTION
Next, the present invention will be described in detail with reference to the accompanying drawings.
FIG. 1 shows an embodiment of a ceramic circuit board according to the present invention, wherein 1 is a ceramic substrate, 2 is a metallized metal layer, and 3 is a metal circuit board.
[0010]
The ceramic substrate 1 has a quadrangular shape, and a through hole 4 penetrating in the thickness direction is formed in a part thereof, and a metal column 5 is inserted into the through hole 4.
[0011]
The ceramic substrate 1 has metallized metal layers 2 deposited on both upper and lower surfaces, and a metal circuit board 3 is brazed to the metallized metal layer 2.
[0012]
The ceramic substrate 1 is made of an electrically insulating material such as an aluminum oxide sintered body, a mullite sintered body, a silicon carbide sintered body, an aluminum nitride sintered body, or a silicon nitride sintered body. In the case of a sintered body, a suitable organic binder, plasticizer, and solvent are added to and mixed with raw material powders such as aluminum oxide, silicon oxide, magnesium oxide, and calcium oxide to form a mud and the mud is well known in the art. A ceramic green sheet (ceramic green sheet) is formed by adopting the doctor blade method and the calender roll method, and then the ceramic green sheet is appropriately punched to have a predetermined shape having a hole to be a through hole 4 Or by firing at a high temperature (about 1600 ° C), or aluminum oxide, etc. An appropriate organic solvent and a solvent are added to and mixed with the raw material powder to prepare the raw material powder, and the raw material powder is formed into a predetermined shape having holes to be through holes 4 by a press molding machine. It is manufactured by firing at a temperature of about 1600 ° C.
[0013]
The ceramic substrate 1 acts as a support member for supporting the metal circuit board 3, and metallized metal layers 2 are formed in a predetermined pattern on both the upper and lower surfaces and the inner wall surface of the through hole 4. A metal circuit board 3 having a predetermined pattern is brazed to the metallized metal layer 2 deposited on the metal plate.
[0014]
The metallized metal layer 2 acts as a base metal layer when the metal circuit board 3 is brazed to the ceramic substrate 1 and is made of a refractory metal material such as tungsten, molybdenum, manganese, etc. For example, an organic binder suitable for tungsten powder A metal paste obtained by adding and mixing a plasticizer and a solvent is preliminarily printed in a predetermined pattern on both the upper and lower surfaces of a ceramic green sheet (ceramic green sheet) to be a ceramic substrate 1 by firing. As a result, the ceramic substrate 1 is deposited on the upper and lower surfaces of the ceramic substrate 1 in a predetermined pattern and a predetermined thickness (10 to 50 μm).
[0015]
The metallized metal layer 2 is formed by depositing a metal having good conductivity such as nickel and gold and having good corrosion resistance and wettability with a brazing material to a thickness of 1 μm to 20 μm by plating. Further, the oxidative corrosion of the metallized metal layer 2 can be effectively prevented, and the brazing between the metallized metal layer 2 and the metal circuit board 3 can be extremely strengthened. Therefore, in order to effectively prevent the oxidative corrosion of the metallized metal layer 2 and to strengthen the brazing between the metallized metal layer 2 and the metal circuit board 3, the surface of the metallized metal layer 2 has good conductivity such as nickel and gold. Thus, it is preferable to deposit a metal having good corrosion resistance and wettability with the brazing material to a thickness of 1 μm to 20 μm.
[0016]
A metal circuit board 3 is attached to the metallized metal layers 2 deposited on the upper and lower surfaces of the ceramic substrate 1 via a brazing material so as to close the through holes 4 provided in the ceramic substrate 1.
[0017]
The metal circuit board 3 is made of a metal material such as copper or aluminum, and is attached to the metallized metal layer 2 deposited on the upper and lower surfaces of the ceramic substrate 1 via a brazing material such as silver brazing.
[0018]
The metal circuit board 3 made of copper, aluminum, or the like has a thickness of, for example, by applying a conventionally known metal processing method such as a rolling method or a stamping method to an ingot (lumb) such as copper or aluminum. A predetermined pattern shape corresponding to the pattern shape of the metallized metal layer 2 is formed at 500 μm.
[0019]
In addition, when the metal circuit board 3 is formed of oxygen-free copper, the oxygen-free copper is not oxidized by the oxygen existing in the copper during the brazing process. The wettability becomes good and the bonding to the metallized metal layer 2 through the brazing material becomes strong. Therefore, the metal circuit board 3 is preferably formed of oxygen-free copper.
[0020]
Further, when the metal circuit board 3 is coated with a metal made of nickel or the like, which has good conductivity, corrosion resistance, and good wettability with a brazing material, by plating. It is possible to effectively prevent the occurrence of oxidative corrosion and to strengthen the electrical connection between the metal circuit board 3 and the external electric circuit and the connection of electronic components such as semiconductor elements to the metal circuit board 3. . Therefore, the metal circuit board 3 is preferably coated with a metal made of nickel or the like, which has good conductivity, corrosion resistance, and good wettability with the brazing material, on the surface thereof.
[0021]
Still further, the metal circuit board 3 is brazed to the metallized metal layer 2 deposited on the ceramic substrate 1 by placing the metal circuit board 3 on the metallized metal layer 2 and, for example, a silver brazing material (silver: 72% by weight, copper: 28% by weight) and brazing material made of aluminum brazing material (aluminum: 88% by weight, silicon: 12% by weight), etc., and then placed on the metal circuit board 3 by 30-100 g. Heat treatment to a predetermined temperature (about 900 ° C. for silver brazing material, about 600 ° C. for aluminum brazing material) in a vacuum or neutral, reducing atmosphere with a load of / cm ² applied. The metallized metal layer 2 and the metal circuit board 3 are joined with the molten brazing material.
[0022]
The ceramic substrate 1 to which the metal circuit board 3 is brazed has metal pillars 5 disposed in the through holes 4, and the metal pillars 5 are brazed to both the upper and lower surfaces of the ceramic substrate 1. It serves to electrically connect the three.
[0023]
The metal column 5 is formed of a highly conductive metal material such as copper (1.7 μΩcm), aluminum (2.7 μΩcm), silver (1.6 μΩcm) having a specific resistance of 4 μΩcm or less. The resistance is as small as 4 μΩcm or less, that is, the conduction resistance of the metal column 5 is small, so that even if a large current exceeding 10 A flows through the metal circuit board 3 and the metal column 5, resistance heat is generated from the metal circuit board 3 and the metal column 5. A large amount of heat is not generated, and as a result, electronic components such as semiconductor elements that are bonded and fixed onto the metal circuit board 3 using an adhesive such as solder are always at an appropriate temperature, and are normal and stable over a long period of time. It can be activated.
[0024]
For example, when the metal pillar 5 is made of copper, the metal pillar 5 is formed in a cylindrical shape by subjecting a copper ingot (lumb) to a conventionally known metal working method such as a rolling method, a punching method, or a drawing method. the provided et the through hole 4 in the substrate 1, metallization has been applied in the through-hole 4 interior wall causes disposed in contact with the metal circuit plate 3 are attached at both ends to the upper and lower surfaces of the ceramic substrate 1 By brazing the metal layer 2 with a brazing material such as silver braze, both ends of the ceramic substrate 1 are in contact with the metal circuit board 3 attached to the upper and lower surfaces of the ceramic substrate 1 in the through hole 4. Be placed.
[0025]
When the metal pillar 5 is formed of oxygen-free copper, the oxygen-free copper is wetted with the brazing material without being oxidized by the oxygen present in the copper surface during brazing. As a result, the bonding property to the metallized metal layer deposited on the inner wall of the through hole 4 of the ceramic substrate 1 through the brazing material becomes strong. Therefore, the metal pillar 5 is preferably formed of oxygen-free copper.
[0026]
If the diameter of the metal column 5 is less than 200 μm, the conduction resistance of the metal column 5 increases, and there is a risk that a large amount of heat is generated due to resistance heating when a large current exceeding 10 A flows. Therefore, the diameter of the metal column 5 is preferably 200 μm or more, preferably 350 μm or more. In particular, if the diameter of the metal column 5 is set to 350 μm or more, even if a large current exceeding 20 A flows through the metal column 5, a large amount of heat due to resistance heat generation is not generated. An electronic component such as a semiconductor element that is bonded and fixed using a material can always be kept at an appropriate temperature, and the electronic component can be operated normally and stably over a long period of time.
[0027]
Thus, according to the above-described ceramic circuit board, electronic components such as semiconductor elements are bonded and fixed to the metal circuit board 3 attached to the upper surface of the ceramic substrate 1 via an adhesive material such as solder and the electronic elements such as the semiconductor elements. When each electrode of the component is electrically connected to the metal circuit board 3 through an electrical connection means such as a bonding wire, the electronic component such as a semiconductor element is mounted on the ceramic circuit board, and at the same time, the metal circuit board 3 is connected to the external electric circuit. When electrically connected to the circuit, an electronic component such as a semiconductor element is connected to an external electric circuit.
[0028]
Next, another embodiment of the present invention will be described with reference to FIGS.
In the figure, the same parts as those in FIG. 1 are denoted by the same reference numerals.
The ceramic circuit board of FIG. 2 has metal circuit boards 3 of a predetermined pattern attached to the upper and lower surfaces of the ceramic board 1 via active metal brazing material 6 and penetrates in the thickness direction provided in the ceramic board 1 at the same time. A metal column 5 is disposed in the hole 4 by attaching its outer surface to the inner wall of the through-hole 4 via the active metal brazing material 6.
[0029]
The metal pillars 5 arranged in the through holes 4 provided in the ceramic substrate 1 are in contact with the metal circuit board 3 at both ends thereof, whereby the metal circuit boards are attached to the upper and lower surfaces of the ceramic substrate 1. 3 is electrically connected through the metal pillar 5.
[0030]
The ceramic substrate 1 having the through holes 4 is made of the same material as that of the above-described embodiment, and is formed into a predetermined shape by the same method.
[0031]
The ceramic substrate 1 has a metal circuit board 3 attached thereto via an active metal brazing material 6 so as to close the through holes 4 provided in the ceramic substrate 1 on both upper and lower sides. It is made of a metal material such as aluminum, and is formed into a predetermined pattern with a thickness of, for example, 500 μm by applying a conventionally known metal processing method such as a rolling method or a punching method to an ingot (lumb) such as copper or aluminum. Is done.
[0032]
If the metal circuit board 3 is formed of oxygen-free copper, the oxygen-free copper is oxidized by oxygen present in the copper when the oxygen-free copper is attached via the active metal brazing material 6. As a result, the wettability with the active metal brazing material 6 is improved and the metal circuit board 3 is firmly attached to the ceramic substrate 1 via the active metal brazing material 6. Therefore, the metal circuit board 3 is preferably formed of oxygen-free copper.
[0033]
The ceramic substrate 1 has metal pillars 5 disposed in the through holes 4, and the metal pillars 5 electrically connect the metal circuit boards 3 brazed to the upper and lower surfaces of the ceramic substrate 1. Make.
[0034]
The metal column 5 is formed of a highly conductive metal material such as copper (1.7 μΩcm), aluminum (2.7 μΩcm), silver (1.6 μΩcm) having a specific resistance of 4 μΩcm or less. The resistance is as small as 4 μΩcm or less, that is, the conduction resistance of the metal column 5 is small, so that even if a large current exceeding 10 A flows through the metal circuit board 3 and the metal column 5, resistance heat is generated from the metal circuit board 3 and the metal column 5. A large amount of heat is not generated, and as a result, electronic components such as semiconductor elements that are bonded and fixed onto the metal circuit board 3 using an adhesive such as solder are always at an appropriate temperature, and are normal and stable over a long period of time. It can be activated.
[0035]
For example, when the metal pillar 5 is made of copper, the metal pillar 5 is formed in a cylindrical shape by subjecting a copper ingot (lumb) to a conventionally known metal working method such as a rolling method, a punching method, or a drawing method. the provided et the through hole 4 in the substrate 1, an active metal brazing material 6 into the through-hole 4 interior wall causes disposed in contact with the metal circuit plate 3 are attached at both ends to the upper and lower surfaces of the ceramic substrate 1 Is attached via.
[0036]
The metal pillar 5 is formed of oxygen-free copper. When the oxygen-free copper is attached in the through hole 4 of the ceramic substrate 1 via the active metal brazing material 6, the copper surface is The wettability with the active metal brazing material 6 is improved without being oxidized by oxygen present in the copper, and the active metal brazing material 6 is firmly bonded to the inner wall of the through hole 4 of the ceramic substrate 1. Therefore, the metal pillar 5 is preferably formed of oxygen-free copper.
[0037]
If the diameter of the metal column 5 is less than 200 μm, the conduction resistance of the metal column 5 increases, and there is a risk that a large amount of heat is generated due to resistance heating when a large current exceeding 10 A flows. Therefore, the diameter of the metal column 5 is preferably 200 μm or more, preferably 350 μm or more. In particular, if the diameter of the metal column 5 is set to 350 μm or more, even if a large current exceeding 20 A flows through the metal column 5, a large amount of heat due to resistance heat generation is not generated. An electronic component such as a semiconductor element that is bonded and fixed using a material can always be kept at an appropriate temperature, and the electronic component can be operated normally and stably over a long period of time.
[0038]
Further, the metal circuit board 3 and the metal pillars 5 are brazed and attached to the upper and lower surfaces of the ceramic substrate 1 and the through holes 4 without using a metallized metal layer by using a metal active brazing material. As the material, when the metal circuit board 3 and the metal pillar 5 are made of copper, a silver-copper eutectic alloy is added with a metal such as titanium, zirconium, hafnium or a hydride thereof in an amount of 2 to 5% by weight. In addition, when the metal circuit board 3 and the metal pillar 5 are made of aluminum, it is preferable to add 2-5% by weight of a metal such as titanium, zirconium, hafnium or a hydride thereof to an aluminum-silicon eutectic alloy. Used for.
[0039]
First, for example, the silver-copper eutectic alloy such as titanium, zirconium, hafnium or the like is attached to the ceramic substrate 1 having the metal circuit board 3 and the metal pillar 5 through-hole 4 using the metal active brazing material. An active metal brazing paste is prepared by mixing an organic solvent and a solvent with a metal or hydride added thereto in an amount of 2 to 5% by weight. Next, the active metal is formed on the upper and lower surfaces of the ceramic substrate 1 and the inner wall of the through hole 4. A brazing paste is applied and applied in a predetermined pattern by adopting a conventionally known screen printing method, and then metal pillars 5 are inserted and disposed in the through holes 4 of the ceramic substrate 1 and on both upper and lower surfaces of the ceramic substrate 1. The metal circuit board 3 is placed on the active metal brazing paste that has been applied by printing, and then is placed in a vacuum or in a neutral or reducing atmosphere at a predetermined temperature (about 9 for copper). Heat treatment at 0 ° C. and about 600 ° C. in the case of aluminum), the active metal brazing material 6 is melted, and the ceramic substrate 1, the metal circuit board 3 and the metal pillars 5 are joined by the melted active metal brazing material 6. Is done by.
[0040]
In the ceramic circuit board, the specific resistance of the metal pillar 5 is as small as 4 μΩcm or less, that is, the conduction resistance of the metal pillar 5 is small, so that a large current exceeding 10 A is applied to the metal circuit board 3 and the metal pillar 5 as in the above-described embodiment. Even if the current flows, a large amount of heat is not generated by the resistance heat generation from the metal circuit board 3 and the metal pillar 5, and as a result, the semiconductor element is bonded and fixed on the metal circuit board 3 using an adhesive such as solder. Such electronic components are always at a suitable temperature, and can be operated normally and stably over a long period of time.
[0041]
Further, in the ceramic circuit board of FIG. 3, a metal circuit board 3 having a predetermined pattern made of copper is attached to the upper and lower surfaces of the ceramic board 1 by the DBC (Direct Bond Copper) method, and at the same time, the thickness direction provided on the ceramic board 1 A metal column 5 is disposed in the through-hole 4 penetrating into the metal circuit board 3 with both ends thereof in contact with the metal circuit board 3.
[0042]
The ceramic substrate 1 having the through holes 4 is made of the same material as that of the above-described embodiment, and is formed into a predetermined shape by the same method.
[0043]
A metal circuit board 3 made of copper is attached by the DBC method so that the ceramic substrate 1 closes the through holes 4 provided in the ceramic substrate 1 on both upper and lower surfaces thereof, and the metal circuit board 3 made of copper is made of copper. By applying a conventionally known metal processing method such as a rolling method or a punching method to the ingot (lumps), a predetermined pattern is formed with a thickness of 500 μm, for example.
[0044]
The metal circuit board 3 is attached to the upper and lower surfaces of the ceramic substrate 1 by placing and contacting the metal circuit board 3 on the upper and lower surfaces of the ceramic substrate 1 so as to close the through holes 4 provided in the ceramic substrate 1. Then, heat treatment is performed at a predetermined temperature (1065 to 1083 ° C.) in a vacuum or in a neutral or reducing atmosphere to form a copper-copper oxide eutectic between the upper surface of the ceramic substrate 1 and the lower surface of the metal circuit board 3. By doing so, it is attached to the surface of the ceramic substrate 1.
[0045]
The metal circuit board 3 made of copper has an oxide film of 0.02 to 0.5 μm formed in advance on its surface, or if the oxygen content is 100 to 2000 ppm, the ceramic substrate 1 and the metal circuit board 3 The copper-copper oxide eutectic becomes easy and the metal circuit board 3 can be bonded and bonded to the ceramic substrate 1 very firmly. Therefore, it is preferable that the metal circuit board 3 made of copper has an oxide film of 0.02 to 0.5 μm formed in advance on its surface, or the oxygen content is set to 100 to 2000 ppm.
[0046]
Further, when the metal circuit board 3 made of copper is coated with a metal made of nickel, which has good conductivity, corrosion resistance, and good wettability with a brazing material, by plating. And electrical connection between the electronic component such as a semiconductor element and an external electric circuit can be made favorable. Therefore, the metal circuit board 3 made of copper is preferably coated with a metal made of nickel, which has good conductivity, corrosion resistance, and good wettability with the brazing material.
[0047]
Further, the ceramic substrate 1 has metal pillars 5 disposed in the through holes 4, and the metal pillars 5 electrically connect the metal circuit boards 3 attached to the upper and lower surfaces of the ceramic substrate 1. Make.
[0048]
The metal column 5 is formed of a highly conductive metal material such as copper (1.7 μΩcm), aluminum (2.7 μΩcm), silver (1.6 μΩcm) having a specific resistance of 4 μΩcm or less. The resistance is as small as 4 μΩcm or less, that is, the conduction resistance of the metal column 5 is small, so that even if a large current exceeding 10 A flows through the metal circuit board 3 and the metal column 5, resistance heat is generated from the metal circuit board 3 and the metal column 5. A large amount of heat is not generated, and as a result, electronic components such as semiconductor elements that are bonded and fixed onto the metal circuit board 3 using an adhesive such as solder are always at an appropriate temperature, and are normal and stable over a long period of time. It can be activated.
[0049]
For example, when the metal pillar 5 is made of copper, the metal pillar 5 is formed into a cylindrical shape by subjecting a copper ingot (lumb) to a conventionally known metal working method such as a rolling method, a punching method, or a drawing method. , is inserted in the the provided et the through-hole 4 the ceramic substrate 1, the metal circuit plate 3 made of copper so as to block the through-holes 4 provided on the ceramic substrate 1 on the upper and lower surfaces of the ceramic substrate 1 DBC method By being attached , both ends are disposed in the through hole 4 so as to be in contact with the metal circuit boards 3 attached to the upper and lower surfaces of the ceramic substrate 1.
[0050]
If the diameter of the metal column 5 is less than 200 μm, the conduction resistance of the metal column 5 increases, and there is a risk that a large amount of heat is generated due to resistance heating when a large current exceeding 10 A flows. Therefore, the diameter of the metal column 5 is preferably 200 μm or more, preferably 350 μm or more. In particular, if the diameter of the metal column 5 is set to 350 μm or more, even if a large current exceeding 20 A flows through the metal column 5, a large amount of heat due to resistance heat generation is not generated. An electronic component such as a semiconductor element that is bonded and fixed using a material can always be kept at an appropriate temperature, and the electronic component can be operated normally and stably over a long period of time.
[0051]
Furthermore, the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the spirit of the present invention.
[0052]
【The invention's effect】
According to the ceramic circuit board of the present invention, there is little pores is located a metal circuit plate which is attached to both surfaces of the ceramic substrate in the through hole of the ceramic substrate, specific resistance of the following metal columns 4Myuomegacm, ends were are placed in contact with the metal circuit plate, since the electrically connected with the metal columns, also occurs the resistance heating in the metal column as a large current of more than 10A on the metal circuit plate and the metal column flows, It does not generate a large amount of heat, and as a result, electronic components such as semiconductor elements that are bonded and fixed onto metal circuit boards using adhesives such as solder are always at the proper temperature, and operate normally and stably over a long period of time. It becomes possible to make it.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view showing an embodiment of a ceramic circuit board according to the present invention.
FIG. 2 is a cross-sectional view showing another embodiment of the present invention.
FIG. 3 is a cross-sectional view showing another embodiment of the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Ceramic substrate 2 ... Metallized metal layer 3 ... Metal circuit board 4 ... Through-hole 5 ... Metal pillar 6 ... Active metal brazing material

Claims

貫通孔を有するセラミック基板の両面に前記貫通孔を塞ぐように金属回路板を取着させるとともに前記貫通孔内に比抵抗が４μΩｃｍ以下の金属材から成る金属柱を、両端が前記金属回路板に接触した状態で配置させ、前記金属柱で前記セラミック基板両面の前記金属回路板を接続したことを特徴とするセラミック回路基板。The metal columns consisting resistivity in the through-hole causes attached a metal circuit plate so as to close the through-hole on both surfaces of the ceramic substrate from the metallic material 4μΩcm having a through hole, the both ends of the metal circuit board is disposed in contact with the state, the ceramic circuit board, characterized in that it connects the metal circuit plate of the ceramic substrate both sides with the metal column.