JP4605887B2

JP4605887B2 - Mounting circuit board and mounting structure of semiconductor device

Info

Publication number: JP4605887B2
Application number: JP2000330136A
Authority: JP
Inventors: 徹細川
Original assignee: Kyocera Corp
Current assignee: Kyocera Corp
Priority date: 2000-10-30
Filing date: 2000-10-30
Publication date: 2011-01-05
Anticipated expiration: 2020-10-30
Also published as: JP2002134648A

Description

【０００１】
【発明の属する技術分野】
本発明は情報通信分野や半導体分野において回路基板や半導体素子収納用パッケージ等に使用される、半導体素子を始めとする各種の半導体装置をいわゆるフリップチップ実装するのに好適な、実装の際の高周波伝送特性を改善した実装用配線基板およびこの実装用配線基板を用いた半導体装置の実装構造に関するものである。
【０００２】
【従来の技術】
近年、回路基板や半導体素子収納用パッケージ等に使用される配線基板に半導体装置を搭載実装する構造として、いわゆるフリップチップ実装が多用されるようになっている。このフリップチップ実装は、一般的には、半導体装置の実装面（通常は下面）側の電極上に金やはんだ材料等によって突起電極を設け、一方、この半導体装置が搭載される配線基板には各突起電極に対応する位置に電極パッドを設けておき、半導体装置の突起電極と配線基板の電極パッドを位置合わせして半導体装置を載置した後に加熱加圧することにより、あるいは超音波エネルギーを印加することにより突起電極と電極パッドとを接合して、半導体装置を配線基板にいわゆるフェースダウンで実装するものである。
【０００３】
このようなフリップチップ実装において配線基板の電極パッドと半導体装置の突起電極とを接合して機械的かつ電気的に接合する方法には、様々な方法が用いられている。例えば、図５（ａ）に側面図で示すように、半導体装置、この例では半導体素子１の下面に形成された突起電極３の先端に例えば銀ペースト９を塗布して配線基板６の搭載部に形成された電極パッド４と当接させて載置した後、同図（ｂ）に同様の側面図で示すように、半導体素子１の上からツール10等により当接部位を加熱加圧して突起電極３と電極パッド４とを銀ペースト９を介して接続する方法がある。
【０００４】
また、半導体装置の突起電極を金で形成し、配線基板の搭載部に形成された電極パッドも金で形成しておき、銀ペーストやはんだ材料を用いずにこれら突起電極と電極パッドとを位置合わせして当接させて載置した後、半導体装置の上から超音波をかけることが可能なツールにより当接部位に超音波を印加して、超音波と加熱のみで突起電極と電極パッドとを接続する方法もある。
【０００５】
これら従来の方法では、半導体装置に設けられる突起電極は、配線基板の電極パッドに対向してこれに接続される端子電極について全て同サイズで設けられる。また、配線基板の電極パッドはそれぞれ半導体装置の突起電極に対向する位置に設けられ、その形状は、配線導体からの延長で導体の幅を太くしたり細くしたりした略四角形のものが一般的である。なお、接地用電極や放熱用の端子については、電極パッドが広面積で形成されたいわゆるベタ部分に半導体装置の複数の突起電極が接合される場合もある。
【０００６】
一方、マイクロ波やミリ波といった高周波帯で使用される半導体装置のフリップチップ実装において重要な点は、高周波信号を、反射や放射や減衰等の損失を少なくして半導体装置に効率良く入出力することである。実装部分において高周波信号に反射や放射や減衰等の損失が生じる原因は、半導体素子の電極と配線基板の電極パッドとの接合部に特性インピーダンスの不一致の箇所が存在することであり、そのような箇所を無くすこと、またはできる限り特性インピーダンスの不一致量を小さくすることが高周波用のフリップチップ実装には重要である。
【０００７】
このためには、一般的に高周波回路においては、半導体装置や配線基板に形成される信号伝送用の線路導体は特性インピーダンスが50Ωとなるように設計されていることから、半導体装置の電極と配線基板の電極パッドとの接続部分の特性インピーダンスを50Ωに近づけることが必要になる。
【０００８】
【発明が解決しようとする課題】
しかしながら、従来の半導体装置のフリップチップ実装においては、半導体装置の端子電極に突起電極を設け、これらを配線基板の対向する位置に設けた略四角形状の電極パッドに位置合わせして当接させることにより搭載実装していたことから、端子電極・突起電極・電極パッド等の接続部分の特性インピーダンスについては考慮されていなかった。このために接続部分において特性インピーダンスの不一致の箇所が存在することとなり、それによって高周波信号の反射や放射や減衰等の損失が大きくなる結果、高周波特性が悪化してしまうという問題点があった。
【０００９】
本発明は上記従来技術における問題点に鑑みてなされたものであり、その目的は、端子電極・突起電極・電極パッド等の接続部分の特性インピーダンスについてこれを50Ωに近づけることができるように考慮して特性インピーダンスの不一致の箇所を無くすことによって、接続部分における高周波信号の反射や放射や減衰等の損失を小さくすることができ、その結果、高周波特性を改善することができる、高周波特性に優れたフリップチップ実装が可能な実装用配線基板およびこの実装用配線基板を用いた半導体装置の実装構造を提供することにある。
【００１０】
【課題を解決するための手段】
本発明の実装用配線基板は、絶縁基板の上面に、下面に信号用突起電極および接地用電極を備えた半導体装置がフリップチップ実装される実装領域を有しており、該実装領域に、前記信号用突起電極に対応して形成された信号用電極パッドと、該信号用電極パッドの形状に応じて同軸線路構造を形成するように前記信号用電極パッドを取り囲んで形成され、かつその前記絶縁基板の上面からの高さが前記信号用電極パッドよりも高い、前記接地用電極が接合される接地用電極パッドとを有することで、断面視したときの同じ高さ位置において、前記信号用突起電極と接続される前記信号用電極パッドの当接部分が前記接地用電極パッドに取り囲まれていることを特徴とするものである。
【００１１】
また、本発明の半導体装置の実装構造は、上記構成の実装用配線基板の前記実装領域に、下面に信号用突起電極およびこの信号用突起電極より高さが低い接地用電極を有する半導体装置を、前記信号用電極パッドに前記信号用突起電極を当接させるとともに前記接地用電極パッドに前記接地用電極を電気的に接続させて実装したことを特徴とするものである。
【００１２】
【発明の実施の形態】
本発明の実装用配線基板によれば、素子面に相当する下面に信号用突起電極および接地用電極を備えた半導体装置がフリップチップ実装される実装領域を絶縁基板の上面に有している実装用配線基板について、この実装領域に、信号用突起電極に対応して形成された信号用電極パッドと、この信号用電極パッドを取り囲んで形成され、かつその絶縁基板の上面からの高さが信号用電極パッドよりも高い、接地用電極が接合される接地用電極パッドとを有するものとしたことから、信号用電極パッドが接地用電極パッドに略同心円状に取り囲まれて電極パッドが同軸線路構造に近くなり、また、この信号用電極パッドに接続される信号用突起電極も接地用電極パッドに接合される接地用電極や接地用導体配線で取り囲んで同様に同軸線路構造に近くすることができるため、半導体装置の端子電極・突起電極と配線基板の電極パッドとの接続部分の特性インピーダンスについても50Ωとなるように考慮することができるので、従来のように半導体装置の端子電極に突起電極を設けて対応する略四角形状の電極パッドに位置合わせしてフリップチップ実装していることにより端子電極・突起電極・電極パッド等の接続部分の特性インピーダンスについては考慮されていない場合と比較して、高周波信号の伝送経路における特性インピーダンスの不一致箇所を無くすことができ、それによって高周波信号の反射や放射や減衰等の損失を小さくすることができるので、高周波特性の悪化をなくすことができる。
【００１３】
また、本発明の実装用配線基板によれば、絶縁基板の上面からの信号用電極パッドの高さ（通常は電極パッドの導体層の厚さに相当する）を接地用電極パッドの高さよりも低くしていることから、信号用電極パッドの周囲が接地用電極パッドによって効果的にシールドされることとなり、信号用電極パッドと信号用突起電極との接続部分に外部から侵入してくるＥＭＩノイズ等の外来ノイズや、高周波信号の一部の接続部分から外部への放射等の損失が極めて低く抑えられるため、高周波信号の伝送経路における特性インピーダンスの不一致箇所を無くすことができるとともに高周波信号の反射や放射や減衰等の損失をさらに小さくすることができ、より効果的に高周波特性の悪化をなくすことができる。
【００１４】
この結果、本発明の実装用配線基板は、半導体装置のフリップチップ実装の接続部分における高周波特性を改善することができ、高周波特性に優れたフリップチップ実装が可能な実装用配線基板となる。
【００１５】
さらに、本発明の実装用配線基板によれば、接地用電極パッドの高さを信号用電極パッドよりも高くしていることから、半導体装置を実装するときに信号用電極パッドと接地用電極パッドとの間に種々の樹脂等を容易に封入することができるので、これにより、接続部分の特性インピーダンスを50Ωにするための設計の自由度も高めることもできる。
【００１６】
また、本発明の半導体装置の実装構造によれば、上記構成の本発明の実装用配線基板の実装領域に、素子面に相当する下面に信号用突起電極および信号用突起電極より下面からの高さが低い接地用電極を有する半導体装置を、信号用電極パッドに信号用突起電極を当接させるとともに接地用電極パッドに接地用電極を電気的に接続させて実装していることから、信号用電極パッドと信号用突起電極および接地用電極パッドと接地用電極により構成される接続部分の構造が同軸線路構造に近いものとなるので、この接続部分の特性インピーダンスについても50Ωとなるように考慮することができて高周波信号の伝送経路における特性インピーダンスの不一致箇所を無くすことができ、それによって高周波信号の反射や放射や減衰等の損失を小さくすることができるので、高周波特性の悪化をなくすことができる。また、実装の接続部分における絶縁基板側の接地用電極パッドの高さを信号用電極パッドよりも高くするとともに、半導体装置側の接地用電極の高さを突起電極を設けない場合あるいは突起電極を設けた場合のいずれも信号用突起電極より低くしていることから、信号用電極パッドおよび信号用突起電極の周囲が接地用電極パッドおよび接地用電極によって効果的にシールドされることとなり、信号用電極パッドと信号用突起電極との接続部分への外来ノイズや、高周波信号の一部の接続部分から外部への放射等の損失が極めて低く抑えられるため、高周波信号の伝送経路における特性インピーダンスの不一致箇所を無くすことができるとともに、高周波信号の反射や放射や減衰等の損失をさらに小さくすることができ、より効果的に高周波特性の悪化をなくすことができる。
【００１７】
この結果、本発明の半導体装置の実装構造は、半導体装置のフリップチップ実装の接続部分における高周波特性を改善することができ、高周波特性に優れたフリップチップ実装構造となる。
【００１８】
さらに、本発明の半導体装置の実装構造によれば、接地用電極パッドの高さを信号用電極パッドよりも高くし、信号用突起電極の高さを接地用電極よりも高くしていることから、半導体装置を実装するときに信号用電極パッドおよび信号用突起電極と接地用電極パッドおよび接地用電極との間に種々の樹脂等を容易に封入することができるので、これにより、接続部分の特性インピーダンスを50Ωにするための設計の自由度も高めることもできる。
【００１９】
以下、図面に基づいて本発明を詳細に説明する。
【００２０】
図１は本発明の実装用配線基板およびそれを用いた本発明の半導体装置の実装構造の実施の形態の一例を示す要部分解斜視図である。図１において、１は半導体装置としての半導体素子であり、半導体素子１は下面に信号用電極２Ｓおよび接地用電極２Ｇを備えており、信号用電極２Ｓには信号用突起電極３が形成されている。この例では、接地用電極２Ｇには突起電極を形成しておらず、これにより接地用電極２Ｇの高さを信号用突起電極３よりも低くしてある。
【００２１】
６は実装用配線基板であり、絶縁基板に所定の配線導体が形成されて半導体素子収納用パッケージやマルチチップモジュール等の高周波電気回路等に使用される。図１においては実装用配線基板６についてその絶縁基板の上面の実装領域を示している。実装用配線基板６の上面の実装領域には、信号用突起電極３に対応して円形状の信号用電極パッド４が金等で形成されており、その信号用電極パッド４の周囲を取り囲むようにして信号用電極パッド４と略同心円状になるように円形状に抜いたパターンをもつ接地用電極パッド５が金等で形成されている。そして、この接地用電極パッド５は、その絶縁基板の上面からの高さを信号用電極パッド４よりも高くして形成されている。なお、この例では、接地用電極パッド５の上面の半導体素子１の接地用電極２Ｇに対向する位置に、接地用電極２Ｇを接合するための金錫等で形成された接地用パターン７を設けている。接地用電極パッド５および接地用パターン７ならびに接地用電極２Ｇは、信号用突起電極３と信号用電極パッド４との接続部分において特性インピーダンスが50Ωとなるように設計して配設したものである。
【００２２】
このような実装用配線基板６に対して半導体素子１の信号用突起電極３と信号用電極パッド４とを位置合わせして当接させ、また接地用電極２Ｇと接地用電極パッド５の接地用パターン７とも当接させて半導体素子１を載置した後、実装用配線基板６を例えば約200℃に加熱するとともに半導体素子１の上からツール（図示せず）を用いて超音波を印加することにより、信号用突起電極３と信号用電極パッド４とを接合する。その後、実装用配線基板６を約300℃まで加熱し、半導体素子１の上からさらに加圧することにより、接地用電極２Ｇと接地用電極パッド５とを接地用パターン７を介して接合する。これにより、本発明の実装用配線基板６に半導体素子１がフリップチップ実装され、本発明の半導体装置の実装構造となる。
【００２３】
このような本発明の実装用配線基板６および半導体装置の実装構造によれば、信号用電極パッド４の周囲にこれを取り囲むように高さが高い接地用電極パッド５が形成されており、信号用電極２Ｓに形成した信号用突起電極３の周囲に同軸線路状に接地用電極パッド５が配置されることとなることから、フリップチップ実装の接続部分において信号用電極パッド４と信号用突起電極３および接地用電極パッド５と接地用電極２Ｇにより構成される構造が同軸線路構造に近いものとなり、接続部分の特性インピーダンスを他の配線導体と同じく50Ωとなるように調整することができて高周波信号の伝送経路における特性インピーダンスの不一致箇所を無くすことができ、また、高周波信号の反射・放射・減衰等の損失も非常に低く抑えることができる。
【００２４】
図２は図１に示した本発明の実装用配線基板６および半導体素子１による本発明の半導体装置の実装構造の実施の形態の一例を示す要部断面図であり、図２において図１と同様の箇所には同じ符号を付してある。なお、信号用電極２Ｓおよび接地用電極２Ｇの図示は省略している。
【００２５】
図２により分かるように、実装用配線基板６の上面に形成された信号用電極パッド４が、接地用電極パッド５よりも高さが低く形成されていることから、信号用突起電極３と信号用電極パッド４との接合部分を通る高周波信号は、この周囲を取り囲んで形成された接地用電極パッド５が略同軸状のシールドの役目を果たし、特性インピーダンスの不一致の低減と、高周波信号の反射・放射・減衰等の損失の低減とが行なえる実装構造となる。
【００２６】
また、このような本発明の半導体装置の実装構造によれば、フリップチップ実装に当たって信号用電極パッド４と接地用電極パッド５との間に例えばエポキシ系等の樹脂を充填することにより、実装強度を上げること等が可能となり、さらに樹脂の誘電率を選ぶことにより電極パッドの大きさについて自由度のある設計が可能になる。
【００２７】
また、信号用電極パッド４を取り囲んで形成される接地用電極パッド５は、円形状や略四角形状等の信号用電極パッド４の形状に応じて同軸線路構造に近い接続構造を構成するように形成される。この場合、信号用電極パッド４と接地用電極パッド５との間隔は、所望の特性インピーダンスとなるように設定すればよい。例えば特性インピーダンスを50Ωとする場合であれば、円形状の信号用電極パッド４の直径が60、80、100、120μｍのとき、接地用電極パッド５との間隔をそれぞれ138、184、230、276μｍの同心円状に設定すればよい。
【００２８】
これら信号用電極パッド４および接地用電極パッド５は、めっき工程や印刷工程を用いて金あるいは銀等によりパターン形成を行なって形成する。
【００２９】
また、信号用突起電極３は、半導体素子１（半導体装置）の信号用電極２Ｓに例えばワイヤボンディング技術の金ボールを用いて金の突起電極を形成するか、または金めっきや印刷等により導体バンプ等の突起電極を形成することによって形成される。なお、接地用電極２Ｇに突起電極を形成する場合にも、同様に形成すればよい。この場合、信号用突起電極３の半導体素子１の下面からの高さは、接地用電極２Ｇまたはその表面に形成した接地用突起電極の高さに対して、上記の信号用電極パッド４と接地用電極パッド５との高さ関係に対応するように設定すればよい。
【００３０】
次に、図３は本発明の実装用配線基板およびこれを用いた本発明の半導体装置の実装構造の実施の形態の他の例を示す、図１と同様の要部分解斜視図である。
【００３１】
図３において図１と同様の箇所には同じ符号を付してあり、１は半導体装置としての半導体素子、２Ｓは半導体素子１の信号用電極、２Ｇは接地用電極である。この例では、信号用電極２Ｓに信号用突起電極３Ｓが形成されるとともに、接地用電極２Ｇには接地用突起電極３Ｇが形成されており、この接地用突起電極３Ｇの高さは信号用突起電極３Ｓよりも低くしてある。
【００３２】
６は実装用配線基板であり、図３においてもその絶縁基板の上面の実装領域を示している。実装用配線基板６の上面の実装領域には、信号用突起電極３Ｓに対応して円形状の信号用電極パッド４が金等で形成されており、その信号用電極パッド４の周囲を取り囲むようにして信号用電極パッド４と略同心円状になるように円形状に抜いたパターンをもつ接地用電極パッド５が金等で、その絶縁基板の上面からの高さを信号用電極パッド４よりも高くして形成されている。この例では、接地用電極パッド５の上面には、接地用突起電極３Ｇを直接に接合することから、接地用電極２Ｇを接合するための金錫等で形成された接地用パターン７は設けていないが、この接地用電極パッド５および接地用突起電極３Ｇが、これらにより信号用突起電極３と信号用電極パッド４との接続部分において特性インピーダンスが50Ωとなるように設計して配設されている。
【００３３】
このような実装用配線基板６に対して半導体素子１の信号用突起電極３Ｓと信号用電極パッド４とを位置合わせして当接させ、また接地用突起電極３Ｇと接地用電極パッド５とも当接させて半導体素子１を載置した後、実装用配線基板６を例えば約200℃に加熱するとともに半導体素子１の上からツール（図示せず）を用いて超音波を印加することにより、信号用突起電極３と信号用電極パッド４とを、ならびに接地用突起電極３Ｇと接地用電極パッド５とを接合する。これにより、本発明の実装用配線基板６に半導体素子１がフリップチップ実装され、本発明の半導体装置の実装構造となる。
【００３４】
このような本発明の実装用配線基板６および半導体装置の実装構造によれば、信号用電極パッド４の周囲にこれを取り囲むように高さが高い接地用電極パッド５が形成されており、信号用電極２Ｓに形成した信号用突起電極３Ｓの周囲に同軸線路状に接地用電極パッド５および接地用突起電極３Ｇが配置されることとなることから、やはりフリップチップ実装の接続部分において信号用電極パッド４と信号用突起電極３Ｓおよび接地用電極パッド５と接地用突起電極３Ｇにより構成される構造が同軸線路構造に近いものとなり、接続部分の特性インピーダンスを他の配線導体と同じく50Ωとなるように調整することができて高周波信号の伝送経路における特性インピーダンスの不一致箇所を無くすことができ、また、高周波信号の反射・放射・減衰等の損失も非常に低く抑えることができる。
【００３５】
図４は図３に示した本発明の実装用配線基板６および半導体素子１による本発明の半導体装置の実装構造の実施の形態の他の例を示す要部断面図であり、図４において図３と同様の箇所には同じ符号を付してある。なお、信号用電極２Ｓおよび接地用電極２Ｇの図示は省略している。
【００３６】
図４により分かるように、実装用配線基板６の上面に形成された信号用電極パッド４が、接地用電極パッド５よりも高さが低く形成されていることから、信号用突起電極３Ｓと信号用電極パッド４との接合部分を通る高周波信号は、この周囲を取り囲んで形成された接地用電極パッド５および接地用突起電極３Ｇが略同軸状のシールドの役目を果たし、特性インピーダンスの不一致の低減と、高周波信号の反射・放射・減衰等の損失の低減とが行なえる実装構造となる。
【００３７】
また、このような本発明の半導体装置の実装構造によっても、フリップチップ実装に当たって信号用電極パッド４と接地用電極パッド５との間に上記の樹脂を充填することにより、実装強度を上げること等が可能となり、さらに樹脂の誘電率を選ぶことにより電極パッドの大きさについて自由度のある設計が可能になる。
【００３８】
【実施例】
次に、本発明の実装用配線基板およびこれを用いた半導体装置の実装構造について具体例を説明する。
【００３９】
まず、配線基板として厚さ0.2ｍｍのセラミック基板を用い、この基板の半導体装置の実装領域に、半導体装置の下面に形成された信号用突起電極と対向する位置に膜厚２μｍの金からなり、直径が80μｍの円形の信号用電極パッドを設けた。また、信号用突起電極と信号用電極パッドとの接続部分の特性インピーダンスが50Ωとなるように、その信号用電極パッドと同心円状となる直径が184μｍの円形パターンを抜いた同軸線路状の接地用電極パッドを信号用電極パッドの周囲に膜厚18μｍで形成し、さらに半導体装置の接地用電極に対向する部分に金錫からなる接地用パターンを形成するとともに半導体装置の信号用突起電極とショートする可能性のある部分にはポリイミド被膜を形成して、本発明の実装用配線基板を用意した。
【００４０】
そして、半導体装置として半導体素子を用意し、その信号用電極には実装後の直径が80μｍ、高さが16μｍとなるような信号用突起電極を形成し、接地用電極には突起電極を形成しない状態で、上記の実装用配線基板に位置合わせしてフリップチップ実装を行なった。このとき、実装用配線基板を約200℃にして半導体素子と位置合わせした後、超音波を印加して信号用突起電極と信号用電極パッドとを接合し、その後、加圧したまま基板温度をさらに上げて約300℃にして、金錫からなる接地用パターンを溶融させることにより接地用電極パッドに接地用電極を接合して、本発明の半導体装置の実装構造の試料Ａを作製した。
【００４１】
また、比較例として、上記と同じ半導体素子に対して従来のよう信号用突起電極と接地用突起電極とを同じ高さで形成したものと、半導体素子の各突起電極に対応する位置に四角形状の電極パッドを設けた従来の実装用配線基板とを用意し、これらを約200℃に加熱し、位置合わせして、超音波を印加することにより、従来のフリップチップ実装構造による試料Ｂを作製した。
【００４２】
そして、これら試料ＡおよびＢについて高周波伝送特性を測定機を用いて測定し、高周波信号に対するそれぞれの損失をパラメータとして、高周波特性の優劣を比較した。その結果、従来の実装構造の試料Ｂでは損失が大きかったのに対し、本発明の実装構造の試料Ａでは実装の接続部分が同軸線路構造に近くなっていることから試料Ｂよりも小さく抑えられており、良好な高周波伝送特性を有していた。
【００４３】
これにより、本発明の実装用配線基板およびこれを用いた半導体装置の実装構造によれば、良好な高周波伝送特性を有するフリップチップ実装が可能となることが確認できた。
【００４４】
次に、上記の実施例では、信号用電極パッドおよび信号用突起電極の直径を80μｍとし、これに対して、その信号用電極パッドと同心円となる直径が184μｍの円形パターンを抜いた同軸線路状の接地用電極パッドを用いたが、これに対して信号用電極パッドおよび信号用突起電極の直径を60μｍ、100μｍ、120μｍとし、それぞれ直径が138μｍ、230μｍ、276μｍの円形パターンを抜いた同軸線路状の接地用電極パッドを用いた場合も、同様の良好な結果が得られた。
【００４５】
なお、以上はあくまで本発明の実施の形態の例示であって、本発明はこれら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種々の変更や改良を加えることは何ら差し支えない。
【００４６】
【発明の効果】
以上のように、本発明の半導体素子の実装基板によれば、絶縁基板の上面に、下面に信号用突起電極および接地用電極を備えた半導体装置がフリップチップ実装される実装領域を有しており、この実装領域に、信号用突起電極に対応して形成された信号用電極パッドと、この信号用電極パッドを取り囲んで形成され、かつその絶縁基板の上面からの高さが信号用電極パッドよりも高い、接地用電極が接合される接地用電極パッドとを有することから、信号用電極パッドが接地用電極パッドに略同心円状に取り囲まれて電極パッドが同軸線路構造に近くなり、また、この信号用電極パッドに接続される信号用突起電極も接地用電極パッドやこれに接合される接地用電極で取り囲んで同様に同軸線路構造に近くすることができるため、半導体装置の信号用突起電極と配線基板の信号用電極パッドとの接続部分の特性インピーダンスについても50Ωとなるように調整することができて高周波信号の伝送経路における特性インピーダンスの不一致箇所を無くすことができ、それによって高周波信号の反射や放射や減衰等の損失を小さくすることができるので、高周波特性の悪化をなくすことができる。
【００４７】
また、本発明の実装用配線基板によれば、絶縁基板の上面からの信号用電極パッドの高さを接地用電極パッドの高さよりも低くしていることから、信号用電極パッドの周囲が接地用電極パッドによって効果的にシールドされることとなり、信号用電極パッドと信号用突起電極との接続部分への外来ノイズや、高周波信号の一部の接続部分から外部への放射等の損失が極めて低く抑えられるため、高周波信号の伝送経路における特性インピーダンスの不一致箇所を無くすことができるとともに高周波信号の反射や放射や減衰等の損失をさらに小さくすることができ、より効果的に高周波特性の悪化をなくすことができる。
【００４８】
この結果、本発明の実装用配線基板によれば、半導体装置のフリップチップ実装の接続部分における高周波特性を改善することができ、高周波特性に優れたフリップチップ実装が可能となる。
【００４９】
さらに、本発明の実装用配線基板によれば、接地用電極パッドの高さを信号用電極パッドよりも高くしていることから、半導体装置を実装するときに信号用電極パッドと接地用電極パッドとの間に種々の樹脂等を容易に封入することができるので、これにより、接続部分の特性インピーダンスを50Ωにするための設計の自由度も高めることもできる。
【００５０】
また、本発明の半導体装置の実装構造によれば、上記構成の本発明の実装用配線基板の実装領域に、下面に信号用突起電極および信号用突起電極より高さが低い接地用電極を有する半導体装置を、信号用電極パッドに信号用突起電極を当接させるとともに接地用電極パッドに接地用電極を電気的に接続させて実装していることから、信号用電極パッドと信号用突起電極および接地用電極パッドと接地用電極により構成される接続部分の構造が同軸線路構造に近いものとなるので、この接続部分の特性インピーダンスについても50Ωとなるように調整することができて高周波信号の伝送経路における特性インピーダンスの不一致箇所を無くすことができ、それによって高周波信号の反射や放射や減衰等の損失を小さくすることができるので、高周波特性の悪化をなくすことができる。また、実装の接続部分における絶縁基板側の接地用電極パッドの高さを信号用電極パッドよりも高くするとともに、半導体装置側の接地用電極の高さを信号用突起電極より低くしていることから、信号用電極パッドおよび信号用突起電極の周囲が接地用電極パッドおよび接地用電極によって効果的にシールドされることとなり、信号用電極パッドと信号用突起電極との接続部分への外来ノイズや、高周波信号の一部の接続部分から外部への放射等の損失が極めて低く抑えられるため、高周波信号の伝送経路における特性インピーダンスの不一致箇所を無くすことができるとともに高周波信号の反射や放射や減衰等の損失をさらに小さくすることができ、より効果的に高周波特性の悪化をなくすことができる。
【００５１】
この結果、本発明の半導体装置の実装構造によれば、半導体装置のフリップチップ実装の接続部分における高周波特性を改善することができ、高周波特性に優れたフリップチップ実装構造となる。
【００５２】
さらに、本発明の半導体装置の実装構造によれば、接地用電極パッドの高さを信号用電極パッドよりも高くし、信号用突起電極の高さを接地用電極よりも高くしていることから、半導体装置を実装するときに信号用電極パッドおよび信号用突起電極と接地用電極パッドおよび接地用電極との間に種々の樹脂等を容易に封入することができるので、これにより、接続部分の特性インピーダンスを50Ωにするための設計の自由度も高めることもできる。
【図面の簡単な説明】
【図１】本発明の実装用配線基板および半導体装置の実装構造の実施の形態の一例を示す要部分解斜視図である。
【図２】図１に示した本発明の実装用配線基板および半導体装置の実装構造の実施の形態の一例を示す要部断面図である。
【図３】本発明の実装用配線基板および半導体装置の実装構造の実施の形態の他の例を示す要部分解斜視図である。
【図４】図３に示した本発明の実装用配線基板および半導体装置の実装構造の実施の形態の他の例を示す要部断面図である。
【図５】（ａ）および（ｂ）はそれぞれ従来の半導体素子の実装方法の例を示す断面図である。
【符号の説明】
１・・・・・・・半導体素子（半導体装置）
２Ｓ・・・・・・信号用電極
２Ｇ・・・・・・接地用電極
３、３Ｓ・・・・信号用突起電極
３Ｇ・・・・・・接地用突起電極
４・・・・・・・信号用電極パッド
５・・・・・・・接地用電極パッド
６・・・・・・・実装用配線基板[0001]
BACKGROUND OF THE INVENTION
The present invention is suitable for flip chip mounting of various semiconductor devices such as semiconductor elements used for circuit boards and semiconductor element storage packages in the fields of information communication and semiconductors. The present invention relates to a mounting wiring board with improved transmission characteristics and a mounting structure of a semiconductor device using the mounting wiring board.
[0002]
[Prior art]
In recent years, so-called flip chip mounting has been widely used as a structure for mounting and mounting a semiconductor device on a wiring board used for a circuit board, a package for housing a semiconductor element, or the like. In flip-chip mounting, generally, a protruding electrode is provided on an electrode on a mounting surface (usually the lower surface) side of a semiconductor device by using gold or a solder material. On the other hand, a wiring board on which the semiconductor device is mounted is provided on a wiring board. An electrode pad is provided at a position corresponding to each protruding electrode, the protruding electrode of the semiconductor device is aligned with the electrode pad of the wiring board, and the semiconductor device is placed and then heated and pressurized, or ultrasonic energy is applied. By doing so, the protruding electrode and the electrode pad are joined, and the semiconductor device is mounted on the wiring board in a so-called face-down manner.
[0003]
In such flip-chip mounting, various methods are used for mechanically and electrically joining the electrode pads of the wiring board and the protruding electrodes of the semiconductor device. For example, as shown in a side view in FIG. 5A, for example, silver paste 9 is applied to the tip of the protruding electrode 3 formed on the lower surface of the semiconductor device, in this example, the semiconductor element 1, and the mounting portion of the wiring board 6 is applied. After being placed in contact with the electrode pad 4 formed on the substrate, the contact part is heated and pressurized with a tool 10 or the like from above the semiconductor element 1 as shown in the same side view in FIG. There is a method of connecting the protruding electrode 3 and the electrode pad 4 via a silver paste 9.
[0004]
In addition, the protruding electrodes of the semiconductor device are formed of gold, and the electrode pads formed on the mounting portion of the wiring board are also formed of gold, and these protruding electrodes and electrode pads are positioned without using silver paste or a solder material. After placing and placing them in contact with each other, an ultrasonic wave is applied to the contact part with a tool capable of applying ultrasonic waves from the top of the semiconductor device, and only the ultrasonic waves and heating are used to form the protruding electrodes and electrode pads. There is also a way to connect.
[0005]
In these conventional methods, the protruding electrodes provided in the semiconductor device are all provided in the same size with respect to the terminal electrodes connected to the electrode pads of the wiring board so as to face each other. In addition, the electrode pads of the wiring board are provided at positions facing the protruding electrodes of the semiconductor device, respectively, and the shape is generally a rectangular shape that is extended from the wiring conductor to increase or decrease the width of the conductor. It is. As for the grounding electrode and the heat radiating terminal, a plurality of protruding electrodes of the semiconductor device may be joined to a so-called solid portion in which the electrode pad is formed in a large area.
[0006]
On the other hand, the important point in flip chip mounting of semiconductor devices used in high frequency bands such as microwaves and millimeter waves is that high frequency signals are efficiently input / output to / from semiconductor devices with reduced losses such as reflection, radiation and attenuation. That is. The reason why losses such as reflection, radiation, and attenuation occur in the high-frequency signal in the mounting part is that there is a mismatched portion of the characteristic impedance at the junction between the electrode of the semiconductor element and the electrode pad of the wiring board. It is important for high-frequency flip-chip mounting to eliminate the portion or to reduce the mismatch amount of the characteristic impedance as much as possible.
[0007]
For this purpose, in general, in a high-frequency circuit, a signal transmission line conductor formed on a semiconductor device or a wiring board is designed to have a characteristic impedance of 50Ω. It is necessary to make the characteristic impedance of the connection portion with the electrode pad of the substrate close to 50Ω.
[0008]
[Problems to be solved by the invention]
However, in conventional flip-chip mounting of a semiconductor device, a protruding electrode is provided on the terminal electrode of the semiconductor device, and these are aligned and brought into contact with a substantially rectangular electrode pad provided at a position facing the wiring board. Therefore, the characteristic impedance of the connection portion such as the terminal electrode, the protruding electrode, and the electrode pad has not been taken into consideration. For this reason, there is a portion where the characteristic impedance does not match in the connection portion, and as a result, the loss of high-frequency signal reflection, radiation, attenuation, or the like increases, resulting in a problem that high-frequency characteristics deteriorate.
[0009]
The present invention has been made in view of the above-described problems in the prior art, and its purpose is to consider the characteristic impedance of the connection portion such as the terminal electrode, the protruding electrode, and the electrode pad so that it can be close to 50Ω. By eliminating the location where the characteristic impedance does not match, it is possible to reduce the loss of reflection, radiation, attenuation, etc. of the high frequency signal at the connection part, and as a result, the high frequency characteristic can be improved, and the high frequency characteristic is excellent. It is an object of the present invention to provide a mounting wiring board capable of flip-chip mounting and a mounting structure of a semiconductor device using the mounting wiring board.
[0010]
[Means for Solving the Problems]
The mounting wiring board of the present invention has a mounting region on which the semiconductor device having the signal projection electrode and the grounding electrode on the lower surface is flip-chip mounted on the upper surface of the insulating substrate. A signal electrode pad formed corresponding to the signal projection electrode; and the signal electrode pad is formed so as to surround the signal electrode pad so as to form a coaxial line structure according to the shape of the signal electrode pad; By having a ground electrode pad to which the ground electrode is joined, the height from the upper surface of the substrate is higher than the signal electrode pad, At the same height when viewed in cross section, The signal electrode pad connected to the signal projection electrode; Contact portion Before It is characterized by being surrounded by the electrode pad for grounding.
[0011]
The semiconductor device mounting structure of the present invention includes a semiconductor device having a signal protruding electrode and a grounding electrode having a lower height than the signal protruding electrode on the lower surface in the mounting region of the mounting wiring board having the above configuration. The signal projecting electrode is brought into contact with the signal electrode pad, and the grounding electrode is electrically connected to the grounding electrode pad and mounted.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
According to the mounting wiring board of the present invention, the mounting having the mounting region on the upper surface of the insulating substrate on which the semiconductor device having the signal projection electrode and the grounding electrode on the lower surface corresponding to the element surface is flip-chip mounted. A wiring board for a signal is formed in the mounting region corresponding to the signal projection electrode, the signal electrode pad is formed so as to surround the signal electrode pad, and the height from the upper surface of the insulating substrate is a signal. The electrode pad for grounding is concentrically surrounded by the electrode pad for grounding, and the electrode pad is coaxial line structure. In addition, the signal projection electrode connected to the signal electrode pad is surrounded by the grounding electrode and the grounding conductor wiring joined to the grounding electrode pad, and similarly formed into a coaxial line structure. Therefore, the characteristic impedance of the connection part between the terminal electrode / projection electrode of the semiconductor device and the electrode pad of the wiring board can be considered to be 50Ω, so that the terminal of the semiconductor device as in the past When the projecting electrodes are provided on the electrodes and the corresponding impedance pads are mounted in a flip chip by aligning with the corresponding rectangular electrode pads, the characteristic impedance of the connection parts such as terminal electrodes, projecting electrodes, and electrode pads is not considered Compared to the above, it is possible to eliminate the mismatched portion of the characteristic impedance in the transmission path of the high frequency signal, thereby reducing the loss of reflection, radiation, attenuation, etc. of the high frequency signal, thereby eliminating the deterioration of the high frequency characteristic. Can do.
[0013]
Further, according to the mounting wiring board of the present invention, the height of the signal electrode pad from the upper surface of the insulating substrate (usually corresponding to the thickness of the conductor layer of the electrode pad) is made higher than the height of the ground electrode pad. Therefore, the periphery of the signal electrode pad is effectively shielded by the ground electrode pad, and the EMI noise that enters from the outside to the connection portion between the signal electrode pad and the signal projection electrode The loss of extraneous noise such as external radiation and radiation from some connected parts of the high-frequency signal to the outside can be suppressed to a very low level. In addition, losses such as radiation and attenuation can be further reduced, and deterioration of high frequency characteristics can be eliminated more effectively.
[0014]
As a result, the mounting wiring board of the present invention can improve the high frequency characteristics in the flip chip mounting connection portion of the semiconductor device, and becomes a mounting wiring board capable of flip chip mounting with excellent high frequency characteristics.
[0015]
Further, according to the mounting wiring board of the present invention, since the height of the ground electrode pad is made higher than that of the signal electrode pad, the signal electrode pad and the ground electrode pad are mounted when the semiconductor device is mounted. Since various resins and the like can be easily enclosed between the two, the degree of freedom in design for setting the characteristic impedance of the connection portion to 50Ω can also be increased.
[0016]
Further, according to the mounting structure of the semiconductor device of the present invention, in the mounting area of the mounting wiring board of the present invention having the above-described configuration, the signal projecting electrode and the signal projecting electrode are formed on the lower surface corresponding to the element surface. A semiconductor device having a low grounding electrode is mounted by contacting a signal projection electrode with a signal electrode pad and electrically connecting a grounding electrode to the grounding electrode pad. Since the structure of the connecting portion composed of the electrode pad and the signal projection electrode and the grounding electrode pad and the grounding electrode is close to the coaxial line structure, the characteristic impedance of this connecting portion is also considered to be 50Ω. It is possible to eliminate the characteristic impedance mismatch point in the transmission path of the high frequency signal, thereby reducing the loss such as reflection, radiation and attenuation of the high frequency signal. Therefore, it is possible to eliminate the deterioration of the high frequency characteristics. Further, the height of the grounding electrode pad on the insulating substrate side in the connecting part of the mounting is made higher than that of the signal electrode pad, and the height of the grounding electrode on the semiconductor device side is set not to be provided with the protruding electrode or the protruding electrode Since both are provided lower than the signal projection electrode, the periphery of the signal electrode pad and the signal projection electrode is effectively shielded by the ground electrode pad and the ground electrode. Loss of extraneous noise to the connection between the electrode pad and signal projection electrode and radiation from some connection parts of the high-frequency signal to the outside can be kept extremely low, resulting in mismatch of characteristic impedance in the transmission path of the high-frequency signal In addition to eliminating parts, it is possible to further reduce losses such as reflection, radiation, and attenuation of high-frequency signals, and more effectively It is possible to eliminate the deterioration of sex.
[0017]
As a result, the mounting structure of the semiconductor device of the present invention can improve the high frequency characteristics in the flip chip mounting connection portion of the semiconductor device, resulting in a flip chip mounting structure with excellent high frequency characteristics.
[0018]
Furthermore, according to the mounting structure of the semiconductor device of the present invention, the height of the ground electrode pad is made higher than that of the signal electrode pad, and the height of the signal protruding electrode is made higher than that of the ground electrode. When mounting a semiconductor device, various resins can be easily sealed between the signal electrode pad and the signal projection electrode and the ground electrode pad and the ground electrode. The degree of freedom in designing to make the characteristic impedance 50Ω can also be increased.
[0019]
Hereinafter, the present invention will be described in detail with reference to the drawings.
[0020]
FIG. 1 is an exploded perspective view of a principal part showing an example of an embodiment of a mounting wiring board of the present invention and a mounting structure of a semiconductor device of the present invention using the same. In FIG. 1, reference numeral 1 denotes a semiconductor element as a semiconductor device. The semiconductor element 1 includes a signal electrode 2S and a ground electrode 2G on the lower surface, and a signal projection electrode 3 is formed on the signal electrode 2S. Yes. In this example, no protruding electrode is formed on the grounding electrode 2G, whereby the height of the grounding electrode 2G is made lower than that of the signal protruding electrode 3.
[0021]
Reference numeral 6 denotes a mounting wiring board, which has a predetermined wiring conductor formed on an insulating substrate, and is used for a high-frequency electric circuit such as a package for housing a semiconductor element or a multichip module. In FIG. 1, the mounting area of the upper surface of the insulating substrate of the mounting wiring substrate 6 is shown. A circular signal electrode pad 4 corresponding to the signal projection electrode 3 is formed of gold or the like in the mounting region on the upper surface of the mounting wiring board 6 so as to surround the periphery of the signal electrode pad 4. Thus, a ground electrode pad 5 having a pattern extracted in a circular shape so as to be substantially concentric with the signal electrode pad 4 is formed of gold or the like. The ground electrode pad 5 is formed such that its height from the upper surface of the insulating substrate is higher than that of the signal electrode pad 4. In this example, a grounding pattern 7 formed of gold tin or the like for joining the grounding electrode 2G is provided on the upper surface of the grounding electrode pad 5 at a position facing the grounding electrode 2G of the semiconductor element 1. ing. The ground electrode pad 5, the ground pattern 7, and the ground electrode 2G are designed and arranged so that the characteristic impedance is 50Ω at the connection portion between the signal projection electrode 3 and the signal electrode pad 4. .
[0022]
The signal projection electrode 3 and the signal electrode pad 4 of the semiconductor element 1 are aligned and brought into contact with the mounting wiring board 6 as described above, and the ground electrode 2G and the ground electrode pad 5 are grounded. After placing the semiconductor element 1 in contact with the pattern 7, the mounting wiring board 6 is heated to, for example, about 200 ° C. and ultrasonic waves are applied from above the semiconductor element 1 using a tool (not shown). As a result, the signal projection electrode 3 and the signal electrode pad 4 are joined. Thereafter, the mounting wiring board 6 is heated to about 300 ° C. and further pressurized from above the semiconductor element 1, thereby joining the grounding electrode 2 G and the grounding electrode pad 5 via the grounding pattern 7. As a result, the semiconductor element 1 is flip-chip mounted on the mounting wiring board 6 of the present invention, and the mounting structure of the semiconductor device of the present invention is obtained.
[0023]
According to the mounting wiring substrate 6 and the semiconductor device mounting structure of the present invention, the ground electrode pad 5 having a high height is formed around the signal electrode pad 4 so as to surround the signal electrode pad 4. Since the ground electrode pad 5 is arranged in a coaxial line around the signal projection electrode 3 formed on the signal electrode 2S, the signal electrode pad 4 and the signal projection electrode are connected at the connecting portion of the flip chip mounting. 3 and the ground electrode pad 5 and the ground electrode 2G are close to the coaxial line structure, and the characteristic impedance of the connection portion can be adjusted to 50Ω as with the other wiring conductors. It is possible to eliminate inconsistencies in the characteristic impedance in the signal transmission path, and to minimize losses such as reflection, radiation, and attenuation of high-frequency signals. wear.
[0024]
FIG. 2 is a cross-sectional view of an essential part showing an example of the embodiment of the mounting structure of the semiconductor device of the present invention by the mounting wiring board 6 and the semiconductor element 1 of the present invention shown in FIG. Similar parts are denoted by the same reference numerals. The signal electrode 2S and the ground electrode 2G are not shown.
[0025]
As can be seen from FIG. 2, the signal electrode pad 4 formed on the upper surface of the mounting wiring board 6 is formed to be lower than the ground electrode pad 5. For the high-frequency signal passing through the joint portion with the electrode pad 4 for grounding, the grounding electrode pad 5 formed so as to surround the periphery serves as a substantially coaxial shield, thereby reducing the mismatch of characteristic impedance and reflecting the high-frequency signal. -A mounting structure that can reduce losses such as radiation and attenuation.
[0026]
Further, according to the mounting structure of the semiconductor device of the present invention, by mounting a resin such as an epoxy resin between the signal electrode pad 4 and the ground electrode pad 5 in flip chip mounting, the mounting strength is increased. In addition, by selecting the dielectric constant of the resin, it is possible to design with flexibility in the size of the electrode pad.
[0027]
Further, the ground electrode pad 5 formed so as to surround the signal electrode pad 4 forms a connection structure close to the coaxial line structure according to the shape of the signal electrode pad 4 such as a circular shape or a substantially square shape. It is formed. In this case, the distance between the signal electrode pad 4 and the ground electrode pad 5 may be set to have a desired characteristic impedance. For example, when the characteristic impedance is 50Ω, when the diameter of the circular signal electrode pad 4 is 60, 80, 100, 120 μm, the distance from the ground electrode pad 5 is 138, 184, 230, 276 μm, respectively. Can be set to be concentric.
[0028]
The signal electrode pad 4 and the ground electrode pad 5 are formed by patterning with gold or silver using a plating process or a printing process.
[0029]
Further, the signal projection electrode 3 is formed by forming a gold projection electrode on the signal electrode 2S of the semiconductor element 1 (semiconductor device) using, for example, a gold ball of wire bonding technology, or conducting bumps by gold plating or printing. It is formed by forming protruding electrodes such as. In addition, what is necessary is just to form similarly, when forming a projection electrode in the electrode 2G for grounding. In this case, the height of the signal projection electrode 3 from the lower surface of the semiconductor element 1 is the same as that of the signal electrode pad 4 and the ground with respect to the height of the ground electrode 2G or the ground projection electrode formed on the surface thereof. What is necessary is just to set so that it may respond | correspond to the height relationship with the electrode pad 5 for an object.
[0030]
Next, FIG. 3 is an exploded perspective view of the main part, similar to FIG. 1, showing another example of the embodiment of the mounting wiring board according to the present invention and the mounting structure of the semiconductor device according to the present invention.
[0031]
In FIG. 3, the same reference numerals are given to the same parts as in FIG. 1, wherein 1 is a semiconductor element as a semiconductor device, 2S is a signal electrode of the semiconductor element 1, and 2G is a ground electrode. In this example, the signal projection electrode 3S is formed on the signal electrode 2S, and the ground projection electrode 3G is formed on the ground electrode 2G. The height of the ground projection electrode 3G is the signal projection. It is lower than the electrode 3S.
[0032]
Reference numeral 6 denotes a mounting wiring board, and FIG. 3 also shows a mounting region on the upper surface of the insulating substrate. A circular signal electrode pad 4 is formed of gold or the like in the mounting region on the upper surface of the mounting wiring board 6 so as to correspond to the signal protruding electrode 3S, and surrounds the periphery of the signal electrode pad 4. The ground electrode pad 5 having a pattern extracted in a circular shape so as to be substantially concentric with the signal electrode pad 4 is gold or the like, and the height from the upper surface of the insulating substrate is higher than that of the signal electrode pad 4. It is formed high. In this example, since the grounding protruding electrode 3G is directly joined to the upper surface of the grounding electrode pad 5, the grounding pattern 7 made of gold tin or the like for joining the grounding electrode 2G is provided. However, the grounding electrode pad 5 and the grounding projection electrode 3G are designed and arranged so that the characteristic impedance is 50Ω at the connection portion between the signal projection electrode 3 and the signal electrode pad 4 due to these. Yes.
[0033]
The signal projection electrode 3S of the semiconductor element 1 and the signal electrode pad 4 are aligned and brought into contact with such a mounting wiring substrate 6, and the grounding projection electrode 3G and the grounding electrode pad 5 are in contact with each other. After placing the semiconductor element 1 in contact, the mounting wiring board 6 is heated to about 200 ° C., for example, and an ultrasonic wave is applied from above the semiconductor element 1 using a tool (not shown) to thereby generate a signal. The projecting electrode 3 and the signal electrode pad 4 are joined together, and the ground projecting electrode 3G and the ground electrode pad 5 are joined together. As a result, the semiconductor element 1 is flip-chip mounted on the mounting wiring board 6 of the present invention, and the mounting structure of the semiconductor device of the present invention is obtained.
[0034]
According to the mounting wiring substrate 6 and the semiconductor device mounting structure of the present invention, the ground electrode pad 5 having a high height is formed around the signal electrode pad 4 so as to surround the signal electrode pad 4. Since the grounding electrode pad 5 and the grounding protruding electrode 3G are arranged in a coaxial line around the signal protruding electrode 3S formed on the electrode 2S for signalling, the signal electrode is also connected at the connecting portion of the flip chip mounting. The structure constituted by the pad 4, the signal protruding electrode 3S, the ground electrode pad 5, and the ground protruding electrode 3G is close to the coaxial line structure, and the characteristic impedance of the connection portion is 50Ω as with the other wiring conductors. Can be adjusted to eliminate the mismatched part of the characteristic impedance in the transmission path of the high-frequency signal. Loss such as attenuation can be kept very low.
[0035]
FIG. 4 is a cross-sectional view of an essential part showing another example of the embodiment of the mounting structure of the semiconductor device of the present invention by the mounting wiring board 6 of the present invention and the semiconductor element 1 shown in FIG. The same parts as those in FIG. The signal electrode 2S and the ground electrode 2G are not shown.
[0036]
As can be seen from FIG. 4, since the signal electrode pad 4 formed on the upper surface of the mounting wiring board 6 is formed to be lower than the ground electrode pad 5, the signal protruding electrode 3S and the signal In the high-frequency signal passing through the joint portion with the electrode pad 4 for grounding, the grounding electrode pad 5 and the grounding protruding electrode 3G formed so as to surround the periphery serve as a substantially coaxial shield, thereby reducing the mismatch of characteristic impedance. And a mounting structure that can reduce losses such as reflection, radiation, and attenuation of high-frequency signals.
[0037]
In addition, according to the mounting structure of the semiconductor device of the present invention, the mounting strength is increased by filling the resin between the signal electrode pad 4 and the ground electrode pad 5 in flip chip mounting. In addition, by selecting the dielectric constant of the resin, it is possible to design with flexibility in the size of the electrode pad.
[0038]
【Example】
Next, specific examples of the mounting wiring board of the present invention and the mounting structure of a semiconductor device using the same will be described.
[0039]
First, a ceramic substrate having a thickness of 0.2 mm is used as the wiring substrate, and the mounting region of the semiconductor device on the substrate is made of gold with a thickness of 2 μm at a position facing the signal projection electrode formed on the lower surface of the semiconductor device. A circular signal electrode pad having a diameter of 80 μm was provided. Also, a coaxial line-shaped grounding with a circular pattern with a diameter of 184 μm concentric with the signal electrode pad so that the characteristic impedance of the connection portion between the signal projection electrode and the signal electrode pad is 50Ω. An electrode pad is formed with a film thickness of 18 μm around the signal electrode pad, and a grounding pattern made of gold-tin is formed in a portion facing the grounding electrode of the semiconductor device and is short-circuited with the signal protruding electrode of the semiconductor device. A polyimide coating was formed on the possible portion to prepare the mounting wiring board of the present invention.
[0040]
Then, a semiconductor element is prepared as a semiconductor device, a signal projection electrode having a diameter of 80 μm and a height of 16 μm is formed on the signal electrode, and no projection electrode is formed on the ground electrode. In this state, flip chip mounting was performed by aligning with the mounting wiring board. At this time, after positioning the mounting wiring board to about 200 ° C. and aligning with the semiconductor element, the ultrasonic wave is applied to join the signal projection electrode and the signal electrode pad, and then the substrate temperature is kept under pressure. The temperature was further raised to about 300 ° C., and the grounding pattern made of gold-tin was melted to bond the grounding electrode to the grounding electrode pad. Thus, sample A of the semiconductor device mounting structure of the present invention was manufactured.
[0041]
As a comparative example, a signal projection electrode and a ground projection electrode are formed at the same height as in the past on the same semiconductor element as described above, and a rectangular shape is formed at a position corresponding to each projection electrode of the semiconductor element. And a conventional mounting wiring board provided with the electrode pads, heated to approximately 200 ° C., aligned, and applied with ultrasonic waves to prepare a sample B having a conventional flip chip mounting structure did.
[0042]
Then, the high frequency transmission characteristics of these samples A and B were measured using a measuring machine, and the superiority and inferiority of the high frequency characteristics were compared using each loss for the high frequency signal as a parameter. As a result, the loss in the conventional mounting structure sample B was large, whereas in the mounting structure sample A of the present invention, the connecting portion of the mounting is close to the coaxial line structure, so it can be kept smaller than the sample B. And had good high-frequency transmission characteristics.
[0043]
As a result, it was confirmed that according to the mounting wiring board of the present invention and the mounting structure of the semiconductor device using the mounting substrate, flip-chip mounting having good high-frequency transmission characteristics can be realized.
[0044]
Next, in the above-described embodiment, the diameter of the signal electrode pad and the signal projection electrode is 80 μm, whereas the diameter of the coaxial electrode is 184 μm concentric with the signal electrode pad. The electrode pad for grounding was used, but the diameter of the electrode pad for signal and the protruding electrode for signal was 60μm, 100μm, 120μm, and the coaxial line shape was cut out of the circular pattern with diameters of 138μm, 230μm, 276μm, respectively The same good results were obtained when the grounding electrode pad was used.
[0045]
Note that the above are merely examples of the embodiments of the present invention, and the present invention is not limited to these embodiments, and various modifications and improvements may be made without departing from the scope of the present invention. .
[0046]
【The invention's effect】
As described above, according to the semiconductor element mounting substrate of the present invention, the upper surface of the insulating substrate has the mounting region in which the semiconductor device having the signal projection electrode and the ground electrode on the lower surface is flip-chip mounted. In this mounting area, the signal electrode pad formed corresponding to the signal projection electrode and the signal electrode pad is formed so as to surround the signal electrode pad, and the height from the upper surface of the insulating substrate is the signal electrode pad. Higher than the grounding electrode pad to which the grounding electrode is joined, so that the signal electrode pad is substantially concentrically surrounded by the grounding electrode pad, and the electrode pad is close to the coaxial line structure, Since the signal projection electrode connected to the signal electrode pad can also be surrounded by the ground electrode pad and the ground electrode joined thereto, similarly to the coaxial line structure, the semiconductor device The characteristic impedance of the connection part between the signal projection electrode and the signal electrode pad of the wiring board can also be adjusted to be 50Ω, and the mismatched part of the characteristic impedance in the transmission path of the high frequency signal can be eliminated. As a result, losses such as reflection, radiation, and attenuation of the high frequency signal can be reduced, so that deterioration of the high frequency characteristics can be eliminated.
[0047]
Further, according to the mounting wiring board of the present invention, since the height of the signal electrode pad from the upper surface of the insulating substrate is lower than the height of the ground electrode pad, the periphery of the signal electrode pad is grounded. This effectively shields the electrode pad for the signal, and the loss of external noise to the connection part between the signal electrode pad and the signal projection electrode and the radiation from the part of the connection part of the high frequency signal to the outside is extremely high. Since it can be kept low, it is possible to eliminate inconsistencies in the characteristic impedance in the transmission path of the high-frequency signal and to further reduce the loss of reflection, radiation, attenuation, etc. of the high-frequency signal. Can be eliminated.
[0048]
As a result, according to the mounting wiring board of the present invention, it is possible to improve the high-frequency characteristics in the connection part of the flip-chip mounting of the semiconductor device, and the flip-chip mounting excellent in the high-frequency characteristics becomes possible.
[0049]
Further, according to the mounting wiring board of the present invention, since the height of the ground electrode pad is made higher than that of the signal electrode pad, the signal electrode pad and the ground electrode pad are mounted when the semiconductor device is mounted. Since various resins and the like can be easily sealed between the two, the degree of freedom in design for setting the characteristic impedance of the connection portion to 50Ω can also be increased.
[0050]
Further, according to the mounting structure of the semiconductor device of the present invention, the mounting area of the mounting wiring board of the present invention having the above-described configuration has the signal protruding electrode and the ground electrode having a lower height than the signal protruding electrode on the lower surface. Since the semiconductor device is mounted with the signal projection electrode in contact with the signal electrode pad and the ground electrode is electrically connected to the ground electrode pad, the signal electrode pad, the signal projection electrode, Since the structure of the connection part composed of the electrode pad for grounding and the electrode for grounding is close to that of the coaxial line structure, the characteristic impedance of this connection part can also be adjusted to be 50Ω to transmit high-frequency signals It is possible to eliminate inconsistent parts of the characteristic impedance in the path and thereby reduce losses such as reflection, radiation and attenuation of high frequency signals. Deterioration of wave characteristics can be eliminated. In addition, the height of the ground electrode pad on the insulating substrate side in the mounting connection portion is made higher than that of the signal electrode pad, and the height of the ground electrode on the semiconductor device side is made lower than that of the signal projecting electrode. Therefore, the periphery of the signal electrode pad and the signal projection electrode is effectively shielded by the ground electrode pad and the ground electrode, so that the external noise and the connection between the signal electrode pad and the signal projection electrode are reduced. Because loss of radiation from some connected parts of the high-frequency signal to the outside can be kept extremely low, it is possible to eliminate mismatched parts of the characteristic impedance in the transmission path of the high-frequency signal and to reflect, radiate or attenuate the high-frequency signal. Loss can be further reduced, and the deterioration of the high frequency characteristics can be eliminated more effectively.
[0051]
As a result, according to the semiconductor device mounting structure of the present invention, it is possible to improve the high frequency characteristics in the flip chip mounting connection portion of the semiconductor device, and the flip chip mounting structure is excellent in high frequency characteristics.
[0052]
Furthermore, according to the mounting structure of the semiconductor device of the present invention, the height of the ground electrode pad is made higher than that of the signal electrode pad, and the height of the signal protruding electrode is made higher than that of the ground electrode. When mounting a semiconductor device, various resins can be easily sealed between the signal electrode pad and the signal projection electrode and the ground electrode pad and the ground electrode. The degree of freedom in designing to make the characteristic impedance 50Ω can also be increased.
[Brief description of the drawings]
FIG. 1 is an exploded perspective view of an essential part showing an example of an embodiment of a mounting structure of a mounting wiring board and a semiconductor device according to the present invention.
2 is a cross-sectional view of an essential part showing an example of an embodiment of a mounting structure of a mounting wiring board and a semiconductor device of the present invention shown in FIG. 1; FIG.
FIG. 3 is an exploded perspective view of a principal part showing another example of the embodiment of the mounting structure of the mounting wiring board and the semiconductor device of the present invention.
4 is a fragmentary cross-sectional view showing another example of the embodiment of the mounting structure of the mounting wiring board and semiconductor device of the present invention shown in FIG. 3; FIG.
FIGS. 5A and 5B are cross-sectional views showing examples of conventional semiconductor element mounting methods, respectively.
[Explanation of symbols]
1 .... Semiconductor element (semiconductor device)
2S ・・・・・・ Signal electrode
2G ... ・ Grounding electrode
3, 3S ··· Signal protruding electrode
3G ･･･ Projection electrode for grounding
4 .... Signal electrode pads
5 .... Earth electrode pad
6 .... Wiring board for mounting

Claims

A semiconductor device having a signal projection electrode and a grounding electrode on the lower surface is mounted on the upper surface of the insulating substrate, and has a mounting area on which the flip chip mounting is performed. The mounting area is formed corresponding to the signal projection electrode. The signal electrode pad is formed so as to surround the signal electrode pad so as to form a coaxial line structure according to the shape of the signal electrode pad, and the height from the upper surface of the insulating substrate is the height By having a grounding electrode pad to which the grounding electrode is bonded, which is higher than the signal electrode pad,
At the same height when viewed in cross section, mounting the wiring board, characterized in that the abutment portion of the signal electrode pad connected to the signal projection electrodes is surrounded before Symbol electrode pads for grounding .

A semiconductor device having a signal projection electrode and a grounding electrode having a lower height than the signal projection electrode on a lower surface in the mounting region of the mounting wiring board according to claim 1, and the signal electrode pad A mounting structure of a semiconductor device, wherein a projecting electrode is brought into contact with the ground electrode and the ground electrode is electrically connected to the ground electrode pad.