JP3914764B2

JP3914764B2 - Optical semiconductor device

Info

Publication number: JP3914764B2
Application number: JP2001394119A
Authority: JP
Inventors: 耕治久保田
Original assignee: Kyocera Corp
Current assignee: Kyocera Corp
Priority date: 2001-12-26
Filing date: 2001-12-26
Publication date: 2007-05-16
Anticipated expiration: 2021-12-26
Also published as: JP2003198028A

Description

【０００１】
【発明の属する技術分野】
本発明は、光通信等の分野に用いられる光半導体素子を収納した光半導体装置に関する。
【０００２】
【従来の技術】
従来の光通信等の分野において高い周波数で作動する半導体レーザ（ＬＤ），フォトダイオード（ＰＤ）等の光半導体素子を気密封止して収納した光半導体装置の例を図２に示す。図２は光半導体素子としてＬＤを内部に収納した光半導体装置の断面図である。同図において、21は基体、22は光半導体素子、23は金属製の蓋体、24は透光性部材、26は光ファイバである。
【０００３】
基体21は鉄（Ｆｅ）−ニッケル（Ｎｉ）−コバルト（Ｃｏ）合金や銅（Ｃｕ）−タングステン（Ｗ）合金等の金属から成り、その上側主面の略中央部には、光半導体素子22が、アルミナ（Ａｌ₂Ｏ₃）質セラミックス等のセラミックスから成る略直方体の基台28を介して基体２１の上側主面に対して垂直な面に搭載固定される。光半導体素子22がこのように搭載されることにより、光半導体素子22から発する光信号が基体21の上方へ出射される。また、基体21には、Ｆｅ−Ｎｉ合金やＦｅ−Ｎｉ−Ｃｏ合金等の金属からなるピン25を挿通させるために両主面間を貫通する貫通孔21ａが形成されており、貫通孔21ａに光半導体装置内外を導通する端子としてのピン25を挿通させるとともに、ピン25と貫通孔21ａとの隙間にガラス等の誘電体から成る接合材を充填させ、基体21とピン25とを気密に接合する。これにより、ピン25が光半導体装置内外を導通する端子として機能する。
【０００４】
なお、基台28に搭載された光半導体素子22は、その電極がピン25の光半導体素子22側の先端とボンディングワイヤ29等を介して電気的に接続されている。
【０００５】
また、基体21の上側主面の外周部に接合され、上端が閉じられ下端が開かれた筒状であり上端面23ａの略中央部に貫通孔23ｂが形成されており、Ｆｅ−Ｎｉ−Ｃｏ合金等の金属から成る蓋体23が設けられる。蓋体23の下端23ｃは、例えば図２のような鍔状となっており、これにより基体21と蓋体23との接合面積が大きくなり、基体21と蓋体23とで構成される容器内部の気密信頼性が向上する。
【０００６】
さらに、貫通孔23ｂを塞ぐように、貫通孔23ｂの上端面23ａ側開口の周囲に透光性部材24が接合される。透光性部材24はガラスやサファイア等から成る円板状，レンズ状，球状または半球状等のものであり、ガラスによる接合や半田付け等により蓋体23に気密に接合される。
【０００７】
このような基体21、蓋体23および透光性部材24から主に構成される容器内部に光半導体素子22を収容し気密に封止する。
【０００８】
最後に、光ファイバ26固定用の筒状の金属製固定部材27が、蓋体23の外周面に溶接され、光ファイバ26が金属製固定部材27の上面の貫通孔に外部から挿通固定されて透光性部材24の上方に固定され、ピン25が外部電気回路（図示せず）に電気的に接続されることによって、光半導体装置となる。
【０００９】
この光半導体装置は、外部電気回路から供給される電気信号によって光半導体素子22にレーザ光等の光を励起させ、この光を透光性部材24、光ファイバ26の順に透過させ、光ファイバ26を介して外部に伝送させることによって、高速光通信等に使用される光半導体装置として機能する。また、この場合、光半導体素子22から光信号が正常に発光しているか確認するためのモニタ用ＰＤ（図示せず）が搭載されていてもよい。
【００１０】
【発明が解決しようとする課題】
しかしながら、上記従来の光半導体装置において、ピン25が基体21の貫通孔21ａに挿通されガラス等を介して気密に接合される構成であるため、ピン25の直径寸法の最小加工限界、貫通孔21ａの孔寸法、隣接する貫通孔21ａ間の間隔の最小加工限界等の制約があり、そのため、基体21にピン25を１本挿入するために大きな面積が必要とされ、基体21に取り付けられるピン25の本数が数本に限られるという問題点があった。その結果、光半導体装置内にはＬＤ等の光半導体素子22とモニタ用ＰＤのみが収容され、光半導体素子22を駆動するためのドライバＩＣは別の半導体素子収納用パッケージ内に収納され、外部電気回路を介してドライバＩＣと光半導体装置とを電気的に接続する必要があり、光半導体素子22を駆動させるための装置全体が大型化するという問題があった。
【００１１】
また、ピン25をガラス等の接合材を介して基体21に接合しただけの端子構造であるため、ピン25に外部から応力が加わわった場合に接合材にクラック等の破損が生じ、光半導体装置内部の気密が損なわれるという問題点があった。
【００１２】
さらに、ピン25の貫通孔21ａの上下開口の部位で高周波信号の反射等が発生し易いため、ピン25の貫通孔21ａに挿入されていない部位を特性インピーダンスに整合させた信号線路とするのが困難であり、ピン25を伝送する高周波信号がピン25で反射等して伝送損失が生じ、高周波信号を効率よく伝送できなくなるという問題点もあった。特に、２ＧＨｚ以上の高周波になると伝送効率が著しく劣化する場合があった。
【００１３】
また、現在光信号の発光源として用いられるＬＤの多くは、光信号が光半導体素子22の端面から発光するため、光ファイバ26方向に発光させるためには、光半導体素子22を基体21の上側主面に対して垂直な面に載置する必要がある。従って、基体21の上側主面に基台28を設け、さらに基台28の基体21の上側主面に垂直な面に光半導体素子22を載置するため、光半導体素子22の実装作業の作業性が悪く手間がかかるという問題点があった。
【００１４】
また、光半導体素子22がＡｌ₂Ｏ₃質セラミックス等からなる基台28を介して基体21に載置されるため、光半導体素子22が発した熱を外部に効率よく放熱できず、光半導体素子22に蓄熱して温度が上昇し、光半導体素子22の光の波長が変動するといった事態が生じ、光半導体素子22が正常に作動しなくなるという問題点があった。
【００１５】
従って、本発明は上記問題点に鑑み完成されたものであり、その目的は、光半導体装置に取り付けられる端子数を増やして内部に収容する集積回路素子（ＩＣ）等の部品を増加させ、光半導体装置を集積化および多機能化させるとともに、高周波信号を効率よく伝送させ得るものとし、また内部の気密信頼性を向上させるとともに光半導体素子の熱を外部に効率よく放熱し、光半導体素子を長期にわたり正常かつ安定に作動させ得るものとすることにある。
【００１６】
【課題を解決するための手段】
本発明の光半導体装置は、平板状の金属製の基体と、上端面の略中央部に貫通孔が形成されているとともに下端が開かれた筒状であり、前記基体の上側主面の外周部に下端が接合された金属製の蓋体と、前記貫通孔の上端面側開口の周囲に接合された透光性部材とを具備した光半導体装置において、前記基体の上下主面間を貫通するように形成された貫通穴に、上面に一辺から対向する他辺にかけて線路導体が形成された誘電体から成る平板部および該平板部の上面に前記線路導体を間に挟んで接合された誘電体から成る立壁部から成る入出力端子が金属板に載置された状態で嵌着されており、該金属板の光半導体装置内側の先端に窒化アルミニウムセラミックスから成る基台を介して光半導体素子が載置されていることを特徴とする。
【００１７】
本発明は、上面に一辺から対向する他辺にかけて線路導体が形成された誘電体から成る平板部および平板部の上面に線路導体を間に挟んで接合された誘電体から成る立壁部から成る入出力端子を具備することにより、平板部の上面に微細な間隔をもって線路導体を多数形成することができ、その結果、光半導体素子，モニタ用ＰＤだけでなく、光半導体素子を駆動するためのドライバＩＣ等の信号入出力をこの入出力端子で行なうことができ、光半導体装置内にドライバＩＣ等も実装することができる。従って、外部電気回路を介して光半導体装置に電気的に接続する必要があったドライバＩＣ等を光半導体装置内に実装し集積化することができることから、光半導体素子を駆動させるための装置全体を小型化できる。
【００１８】
また、この入出力端子によって、平板部の上面に形成した線路導体のインピーダンスを特性インピーダンスに整合させることができ、入出力端子の線路導体を伝送する信号が高周波になっても、高周波信号を効率よく伝送でき、また入出力端子部の気密信頼性が向上する。
【００１９】
また本発明では、金属板に入出力端子を載置するとともに、金属板の光半導体装置内側の先端に窒化アルミニウム（ＡｌＮ）セラミックスから成る基台を接合した後に入出力端子および金属板を基体に嵌着すればよいことから、容易に基台を光半導体装置内に接合できるとともに、光半導体素子の端面から発光する光信号を光ファイバ方向に発光させることができ、また光半導体素子の熱を熱伝導率の高いＡｌＮセラミックスから成る基台と金属板を介して外部に効率よく放熱できる。従って、基台の接合作業の作業性が向上するとともに、光半導体素子の熱を外部に効率よく放熱でき、光半導体素子に蓄熱して温度が上昇するのを防止して光半導体素子を正常に作動させ得る。
【００２０】
【発明の実施の形態】
本発明の光半導体装置について以下に詳細に説明する。図１は本発明の光半導体装置について実施の形態の一例を示す断面図であり、１は基体、２は光半導体素子、３は金属製の蓋体、４は透光性部材、５は入出力端子、６は光ファイバである。
【００２１】
本発明の光半導体装置は、平板状の金属製の基体１と、上端面３ａの略中央部に貫通孔３ｂが形成されているとともに下端３ｃが開かれた筒状であり、基体１の上側主面の外周部に下端３ｃが接合された金属製の蓋体３と、貫通孔３ｂの上端面３ａ側開口の周囲に接合された透光性部材４とを具備し、基体１の上下主面間を貫通するように形成された貫通穴１ａに、上面に一辺から対向する他辺にかけて線路導体５ｃが形成された誘電体から成る平板部５ｂおよび平板部５ｂの上面に線路導体５ｃを間に挟んで接合された誘電体から成る立壁部５ａから成る入出力端子５が金属板10に載置された状態で嵌着されており、金属板10の光半導体装置内側の先端に窒化アルミニウムセラミックスから成る基台８を介して光半導体素子２が載置されている構成である。
【００２２】
本発明の基体１は、略円板状、略長方形等の平板状であり、Ｆｅ−Ｎｉ−Ｃｏ合金やＣｕ−Ｗ合金等の金属から成り、そのインゴットに圧延加工や打ち抜き加工等の従来周知の金属加工法を施すことによって所定形状に製作される。この基体１には、Ａｌ₂Ｏ₃質セラミックス等の誘電体から成る平板部５ｂおよびＡｌ₂Ｏ₃質セラミックス等の誘電体から成る立壁部５ａとを具備した入出力端子５および平板部５ｂの下面に接合された金属板10とを挿入するために、基体１の上下主面間を貫通する貫通穴１ａが設けられている。この貫通穴１ａに、光半導体装置内外を導通する入出力端子５および金属板10を挿通し、入出力端子５および金属板10と貫通穴１ａとの隙間に銀（Ａｇ）ろう等のろう材を充填させ、基体１と入出力端子５および金属板10とをろう付けして気密に接合する。
【００２３】
また、入出力端子５を構成する平板部５ｂおよび立壁部５ａは以下のようにして作製される。例えば、Ａｌ₂Ｏ₃質セラミックスから成る場合、先ず酸化アルミニウム、酸化珪素（ＳｉＯ₂）、酸化マグネシウム（ＭｇＯ）および酸化カルシウム（ＣａＯ）等の原料粉末に適当な有機バインダー、可塑剤、溶剤等を添加混合して泥漿状と成す。これ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等のテープ成形技術により複数のセラミックグリーンシートを得る。次に、このセラミックグリーンシートに、タングステン（Ｗ）やモリブデン（Ｍｏ）等の高融点金属粉末に適当な有機バインダー、可塑剤、溶剤等を添加混合して得た金属ペーストを、スクリーン印刷法等の厚膜形成技術により印刷塗布して、線路導体５ｃとなるメタライズ配線層を所定パターンに形成する。また、平板部５ｂの下面には、金属板10をＡｇろう等によりろう付けできるように、メタライズ層を全面に印刷塗布しておくのがよい。その後、セラミックグリーンシートを複数枚積層し、これを還元雰囲気中、約1600℃の温度で焼成することにより製作される。このようにして、入出力端子５に特性インピーダンスに整合された線路導体５ｃが形成される。
【００２４】
金属板10は、略長方形であり、Ｆｅ−Ｎｉ−Ｃｏ合金やＣｕ−Ｗ合金等の金属から成り、そのインゴットに圧延加工や打ち抜き加工等の従来周知の金属加工法を施すことによって所定形状に製作される。この金属板10の入出力端子５が載置された主面の光半導体装置内側の先端部には、ＡｌＮセラミックスからなる光半導体素子２を載置するための略直方体の基台８がＡｇろう等によりろう付けされている。
【００２５】
基台８には光半導体素子２が載置される主面にＷやＭｏ等からなる線路導体８ａが設けられているのがよい。即ち、基台８に搭載された光半導体素子２は、その電極が線路導体８ａの光半導体素子２側の先端とボンディングワイヤ９等を介して電気的に接続され、線路導体８ａと線路導体５ｃとがボンディングワイヤ９等を介して電気的に接続されるので、光半導体素子２の電極を、入出力端子５の線路導体５ｃに直接接続するのではなく、基台８の線路導体８ａに接続することにより、ボンディングワイヤ９の長さを短くでき、ボンディングワイヤ９による高周波信号の伝送損失を最小限に抑えられる。また、基台８の他方の主面には金属板10とをろう付けするためにＷやＭｏ等からなるメタライズ層を全面に印刷塗布しておく。
【００２６】
この基台８はＡｌＮセラミックスからなるため、光半導体素子２が作動時に発する熱を効率よく金属板10に伝達し、金属板10の光半導体装置外側の部位から外部に効率よく放熱できる。従って、光半導体素子２の熱を外部に効率よく放熱でき、光半導体素子２に蓄熱して温度が上昇するのを防止し、光半導体素子２を正常に作動させ得る。
【００２７】
また、入出力端子５がＡｌＮセラミックスから成り基台８と一体に成形されていてもよいが、ＡｌＮセラミックスはＡｌ₂Ｏ₃セラミックスに比して入出力端子５の製作コストが高くなるため、光半導体素子２の熱を外部に効率よく放熱するためには、基台８のみがＡｌＮセラミックスから成るようにすれば十分である。
【００２８】
また、基体１の上側主面の外周部には、上端面３ａの略中央部に貫通孔３ｂが形成され下端が開かれた筒状である蓋体３が設けられる。蓋体３の下端３ｃは、鉛（Ｐｂ）−錫（Ｓｎ）半田等の半田による半田付けや溶接等によって基体１と気密に接合される。下端３ｃは、基体１との接合面積を大きくして、基体１と蓋体３とで構成される容器内部の気密信頼性を向上させるために、図１に示すような鍔状であることが好ましい。
【００２９】
蓋体３は、断面形状（横断面形状）が円形または長方形等の多角形の筒状であり、Ｆｅ−Ｎｉ−Ｃｏ合金等の金属のインゴットに圧延加工や打ち抜き加工等の従来周知の金属加工法を施すことによって所定形状に製作される。なお、蓋体３は、筒状部と上端面３ａが個々に製作され、それらをろう付け、半田付け、溶接等によって接合したものであってもよい。
【００３０】
蓋体３には、貫通孔３ｂを塞ぐように貫通孔３ｂの上端面３ａ側開口の周囲に、透光性部材４がガラス接合や半田付け等により気密に接合される。透光性部材４は、ガラスやサファイア等から成る円板状，レンズ状，球状または半球状等のものであり、球状の場合周縁部で、円板状やレンズ状の場合一主面の外周部で、半球状の場合平面部の外周部で蓋体３に接合される。
【００３１】
また、光ファイバ６は、Ｆｅ−Ｎｉ−Ｃｏ合金等の金属から成る略円筒状の金属製固定部材７の上端面に固定されており、金属製固定部材７の下端面が蓋体３の外周面にレーザ溶接法等の溶接によって接合される。光ファイバ６が金属製固定部材７を介して透光性部材４の上方に固定されることによって、製品としての光半導体装置となる。これにより、光ファイバ６を介して内部に収容する光半導体素子２と外部との光信号の授受が可能となる。
【００３２】
本発明において、透光性部材４は貫通孔３ｂの上端面３ａ側開口の周囲に接合されるのが好ましく、この場合以下の点で有利である。即ち、蓋体３の外周部に金属製固定部材７を溶接する際の熱が蓋体３に局所的に加わり、蓋体３の透光性部材４との接合面に熱膨張による引っ張り応力が加わると、透光性部材４が蓋体３から剥がれ易くなるが、光半導体装置は内部を気密にするため外側から内側に気圧が加わるため、気圧によって透光性部材４が蓋体３に押し付けられて剥がれにくくなる。一方、透光性部材４が貫通孔３ｂの上端面３ａの裏面側開口の周囲に接合されていると、熱膨張による応力によって透光性部材４を剥がそうとする引っ張り応力と気圧による圧力とが、透光性部材４が蓋体３から容易に外れてしまうこととなる。
【００３３】
また本発明において、入出力端子５の平板部５ｂの上面と基台８の光半導体素子２の載置面とが略面一であることが好ましい。この場合、線路導体５ｃと線路導体８ａとを接続するボンディングワイヤ９の長さが最短化されるとともに、そのインダクタンスも小さくなる。また、ボンディングワイヤ９を使用せずに、板状の金属片で接続することもできる。板状の金属片であればさらにインダクタンスが小さくなり、また金属片においてインピーダンスを調整することもできる。
【００３４】
本発明の光半導体装置は、光半導体素子２の電極を外部電気回路に電気的に接続し、製品としての光半導体装置となる。この光半導体装置は、外部電気回路から供給される電気信号によって光半導体素子２に光を励起させ、この光を透光性部材４、光ファイバ６の順に透過させ、光ファイバ６を介して外部に伝送することによって、高速光通信等に使用される光半導体装置として機能する。
【００３５】
なお、本発明は上記実施の形態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内であれば種々の変更を施すことは何等差し支えない。
【００３６】
【発明の効果】
本発明は、平板状の金属製の基体と、上端面の略中央部に貫通孔が形成されているとともに下端が開かれた筒状であり、前記基体の上側主面の外周部に下端が接合された金属製の蓋体と、貫通孔の上端面側開口の周囲に接合された透光性部材とを具備し、基体の上下主面間を貫通するように形成された貫通穴に、上面に一辺から対向する他辺にかけて線路導体が形成された誘電体から成る平板部および平板部の上面に線路導体を間に挟んで接合された誘電体から成る立壁部から成る入出力端子が金属板に載置された状態で嵌着されており、金属板の光半導体装置内側の先端に窒化アルミニウムセラミックスから成る基台を介して光半導体素子が載置されていることにより、入出力端子の平板部の上面に微細な間隔をもって線路導体を多数形成することができ、その結果、光半導体素子，モニタ用ＰＤだけでなく、光半導体素子を駆動するためのドライバＩＣ等の信号入出力を入出力端子で行なうことができ、従って光半導体装置内にドライバＩＣ等も実装することができる。このように、外部電気回路を介して光半導体装置に電気的に接続する必要があったドライバＩＣ等を光半導体装置内に実装し集積化できることから、光半導体素子を駆動させるための装置全体を小型化できる。
【００３７】
また、入出力端子を伝送される信号が高周波になっても、高周波信号を効率よく伝送でき、また入出力端子部の気密信頼性が向上する。
【００３８】
さらに、金属板に入出力端子を載置するとともに金属板の光半導体装置内側の先端に基台を接合した後に、入出力端子および金属板を基体に嵌着できるため、容易に基台を光半導体装置内に接合できるとともに、光半導体素子の端面から発光する光信号を光ファイバ方向に発光させることができ、また光半導体素子の熱を熱伝導率の高いＡｌＮセラミックスから成る基台と金属板を介して外部に効率よく放熱できる。その結果、光半導体素子の実装作業の作業性が向上するとともに、光半導体素子の熱を外部に効率よく放熱でき、光半導体素子に蓄熱して温度が上昇するのを防いで光半導体素子を正常に作動させ得る。
【図面の簡単な説明】
【図１】本発明の光半導体装置について実施の形態の例を示す断面図である。
【図２】従来の光半導体装置の断面図である。
【符号の説明】
１：基体
１ａ：貫通穴
２：光半導体素子
３：蓋体
３ａ：上端面
３ｂ：貫通孔
４：透光性部材
５：入出力端子
５ａ：立壁部
５ｂ：平板部
５ｃ：線路導体
８：基台
１０：金属板[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an optical semiconductor device containing an optical semiconductor element used in fields such as optical communication.
[0002]
[Prior art]
FIG. 2 shows an example of an optical semiconductor device in which optical semiconductor elements such as a semiconductor laser (LD) and a photodiode (PD) that operate at a high frequency in a field of conventional optical communication and the like are hermetically sealed. FIG. 2 is a cross-sectional view of an optical semiconductor device in which an LD is housed as an optical semiconductor element. In the figure, 21 is a base, 22 is an optical semiconductor element, 23 is a metal lid, 24 is a translucent member, and 26 is an optical fiber.
[0003]
The base 21 is made of a metal such as an iron (Fe) -nickel (Ni) -cobalt (Co) alloy or copper (Cu) -tungsten (W) alloy. Is mounted and fixed on a surface perpendicular to the upper main surface of the base 21 through a substantially rectangular parallelepiped base 28 made of ceramic such as alumina (Al ₂ O ₃ ) ceramic. By mounting the optical semiconductor element 22 in this manner, an optical signal emitted from the optical semiconductor element 22 is emitted above the base 21. Further, the base 21 is formed with a through hole 21a penetrating between both main surfaces in order to insert a pin 25 made of a metal such as Fe-Ni alloy or Fe-Ni-Co alloy. A pin 25 as a terminal conducting inside and outside of the optical semiconductor device is inserted, and a gap between the pin 25 and the through hole 21a is filled with a bonding material made of a dielectric material such as glass, and the base 21 and the pin 25 are bonded in an airtight manner. To do. As a result, the pin 25 functions as a terminal for conducting the inside and outside of the optical semiconductor device.
[0004]
The electrode of the optical semiconductor element 22 mounted on the base 28 is electrically connected to the tip of the pin 25 on the optical semiconductor element 22 side via a bonding wire 29 or the like.
[0005]
Further, it is joined to the outer peripheral portion of the upper main surface of the base 21 and has a cylindrical shape in which the upper end is closed and the lower end is opened, and a through hole 23b is formed in a substantially central portion of the upper end surface 23a, and Fe-Ni-Co A lid 23 made of a metal such as an alloy is provided. The lower end 23c of the lid body 23 has, for example, a bowl shape as shown in FIG. 2, thereby increasing the bonding area between the base body 21 and the lid body 23, and the inside of the container constituted by the base body 21 and the lid body 23. Improves airtight reliability.
[0006]
Furthermore, the translucent member 24 is joined around the opening on the upper end surface 23a side of the through hole 23b so as to close the through hole 23b. The translucent member 24 has a disk shape, a lens shape, a spherical shape, a hemispherical shape, or the like made of glass, sapphire, or the like, and is airtightly bonded to the lid body 23 by bonding or soldering with glass.
[0007]
The optical semiconductor element 22 is accommodated in a container mainly composed of the base 21, the lid 23, and the translucent member 24, and hermetically sealed.
[0008]
Finally, a cylindrical metal fixing member 27 for fixing the optical fiber 26 is welded to the outer peripheral surface of the lid 23, and the optical fiber 26 is inserted and fixed from the outside into the through hole on the upper surface of the metal fixing member 27. An optical semiconductor device is obtained by being fixed above the translucent member 24 and electrically connecting the pin 25 to an external electric circuit (not shown).
[0009]
This optical semiconductor device excites light, such as laser light, into the optical semiconductor element 22 by an electrical signal supplied from an external electrical circuit, and transmits this light in the order of the translucent member 24 and the optical fiber 26. By transmitting the signal to the outside via the optical device, it functions as an optical semiconductor device used for high-speed optical communication or the like. In this case, a monitor PD (not shown) for confirming whether the optical signal is normally emitted from the optical semiconductor element 22 may be mounted.
[0010]
[Problems to be solved by the invention]
However, in the above conventional optical semiconductor device, since the pin 25 is inserted into the through hole 21a of the base 21 and is hermetically joined via glass or the like, the minimum processing limit of the diameter dimension of the pin 25, the through hole 21a There are restrictions such as the minimum processing limit of the hole size and the interval between the adjacent through holes 21a. Therefore, a large area is required for inserting one pin 25 into the base 21, and the pin 25 attached to the base 21 is required. There was a problem that the number of was limited to a few. As a result, only the optical semiconductor element 22 such as LD and the monitor PD are accommodated in the optical semiconductor device, and the driver IC for driving the optical semiconductor element 22 is accommodated in another semiconductor element accommodating package, There is a problem that the driver IC and the optical semiconductor device need to be electrically connected via an electric circuit, and the entire device for driving the optical semiconductor element 22 is increased in size.
[0011]
In addition, since the pin 25 has a terminal structure in which the pin 25 is simply bonded to the base 21 via a bonding material such as glass, when the external stress is applied to the pin 25, damage such as cracks occurs in the bonding material, and the optical semiconductor There was a problem that the airtightness inside the apparatus was impaired.
[0012]
Furthermore, since high frequency signals are likely to be reflected at the upper and lower openings of the through hole 21a of the pin 25, the signal line in which the portion not inserted into the through hole 21a of the pin 25 is matched to the characteristic impedance is used. There is also a problem that the high-frequency signal transmitted through the pin 25 is reflected by the pin 25 and transmission loss occurs, and the high-frequency signal cannot be transmitted efficiently. In particular, when the frequency becomes 2 GHz or higher, the transmission efficiency may be significantly deteriorated.
[0013]
In addition, since many of the LDs currently used as light emission sources for optical signals emit light from the end face of the optical semiconductor element 22, the optical semiconductor element 22 is placed above the base 21 in order to emit light toward the optical fiber 26. It must be placed on a surface perpendicular to the main surface. Accordingly, the base 28 is provided on the upper main surface of the base 21, and the optical semiconductor element 22 is placed on a surface perpendicular to the upper main surface of the base 21 of the base 28. There was a problem that it was poor in nature and time consuming.
[0014]
Further, since the optical semiconductor element 22 is mounted on the base 21 via the base 28 made of Al ₂ O ₃ ceramics or the like, the heat generated by the optical semiconductor element 22 cannot be efficiently radiated to the outside, and the optical semiconductor There is a problem that the temperature of the element 22 increases due to heat storage and the wavelength of light of the optical semiconductor element 22 fluctuates, and the optical semiconductor element 22 does not operate normally.
[0015]
Accordingly, the present invention has been completed in view of the above problems, and its object is to increase the number of terminals attached to the optical semiconductor device and increase the number of components such as integrated circuit elements (ICs) accommodated therein, and Semiconductor devices are integrated and multifunctional, and high-frequency signals can be transmitted efficiently, and the internal airtight reliability is improved and the heat of the optical semiconductor element is efficiently radiated to the outside. It is to be able to operate normally and stably over a long period of time.
[0016]
[Means for Solving the Problems]
The optical semiconductor device of the present invention has a flat metal base, a cylindrical shape having a through hole formed at a substantially central portion of the upper end surface and an open lower end, and an outer periphery of the upper main surface of the base. In an optical semiconductor device comprising a metal lid having a lower end joined to a portion and a translucent member joined around the opening on the upper end surface side of the through hole, it penetrates between the upper and lower main surfaces of the substrate. A dielectric plate formed of a dielectric having a line conductor formed from one side to the opposite side of the upper surface and a top surface of the flat plate portion with the line conductor sandwiched in between. An input / output terminal composed of a standing wall portion made of a body is fitted in a state of being mounted on a metal plate, and an optical semiconductor element is attached to the tip of the metal plate inside the optical semiconductor device via a base made of aluminum nitride ceramics Is mounted.
[0017]
The present invention comprises a flat plate portion made of a dielectric having a line conductor formed on one side from the other side to the opposite side, and a standing wall portion made of a dielectric joined to the upper surface of the flat plate portion with the line conductor interposed therebetween. By providing the output terminal, a large number of line conductors can be formed on the upper surface of the flat plate portion with fine intervals. As a result, not only the optical semiconductor element and the monitoring PD but also a driver for driving the optical semiconductor element. Signal input / output of an IC or the like can be performed at this input / output terminal, and a driver IC or the like can be mounted in the optical semiconductor device. Accordingly, since a driver IC or the like that needs to be electrically connected to the optical semiconductor device via an external electric circuit can be mounted and integrated in the optical semiconductor device, the entire device for driving the optical semiconductor element Can be miniaturized.
[0018]
This input / output terminal allows the impedance of the line conductor formed on the upper surface of the flat plate portion to be matched to the characteristic impedance, so that even if the signal transmitted through the line conductor of the input / output terminal becomes a high frequency, the high-frequency signal is efficiently processed. It can transmit well and the airtight reliability of the input / output terminal is improved.
[0019]
In the present invention, the input / output terminals are mounted on the metal plate, and the base made of aluminum nitride (AlN) ceramic is joined to the tip of the metal plate inside the optical semiconductor device, and then the input / output terminals and the metal plate are mounted on the base. The base can be easily joined into the optical semiconductor device, and the optical signal emitted from the end face of the optical semiconductor element can be emitted in the direction of the optical fiber, and the heat of the optical semiconductor element can be reduced. Heat can be efficiently radiated to the outside through a base made of AlN ceramics with high thermal conductivity and a metal plate. Therefore, the workability of the joining work of the base is improved, the heat of the optical semiconductor element can be efficiently radiated to the outside, the temperature of the optical semiconductor element is prevented from being increased by storing heat, and the optical semiconductor element is normally operated. Can be activated.
[0020]
DETAILED DESCRIPTION OF THE INVENTION
The optical semiconductor device of the present invention will be described in detail below. FIG. 1 is a cross-sectional view showing an embodiment of an optical semiconductor device according to the present invention. 1 is a base, 2 is an optical semiconductor element, 3 is a metal lid, 4 is a translucent member, and 5 is an insertion. An output terminal 6 is an optical fiber.
[0021]
The optical semiconductor device of the present invention has a flat metal base 1 and a cylindrical shape in which a through hole 3b is formed in a substantially central portion of an upper end surface 3a and a lower end 3c is opened. A metal lid 3 having a lower end 3c bonded to the outer peripheral portion of the main surface, and a translucent member 4 bonded around the opening on the upper end surface 3a side of the through hole 3b. A flat plate portion 5b made of a dielectric in which a line conductor 5c is formed from one side to the other side facing the upper surface in a through hole 1a formed so as to penetrate between the planes, and the line conductor 5c between the upper surface of the flat plate portion 5b. An input / output terminal 5 consisting of a standing wall portion 5a made of a dielectric material sandwiched between the two is fitted in a state of being placed on the metal plate 10, and aluminum nitride ceramics is attached to the tip of the metal plate 10 inside the optical semiconductor device. The optical semiconductor element 2 is placed via a base 8 made of This is a configuration.
[0022]
The substrate 1 of the present invention has a flat plate shape such as a substantially disk shape or a substantially rectangular shape, and is made of a metal such as a Fe—Ni—Co alloy or a Cu—W alloy. Conventionally well-known such as rolling or punching the ingot. It is manufactured in a predetermined shape by applying the metal processing method. This base body 1, the Al ₂ O ₃ quality ceramics dielectric plate portion 5b made of and Al ₂ O ₃ quality ceramics such input-output terminal 5 and the flat plate portion 5b to and a vertical wall portion 5a made of a dielectric In order to insert the metal plate 10 bonded to the lower surface, a through hole 1a penetrating between the upper and lower main surfaces of the base 1 is provided. Through the through hole 1a, the input / output terminal 5 and the metal plate 10 that are electrically connected to the inside and outside of the optical semiconductor device are inserted, and a brazing material such as silver (Ag) solder is inserted into the gap between the input / output terminal 5 and the metal plate 10 and the through hole 1a. And the base body 1, the input / output terminal 5 and the metal plate 10 are brazed and hermetically bonded.
[0023]
Further, the flat plate portion 5b and the standing wall portion 5a constituting the input / output terminal 5 are manufactured as follows. For example, in the case of an Al ₂ O ₃ ceramic, first, an appropriate organic binder, plasticizer, solvent, etc. are added to raw material powders such as aluminum oxide, silicon oxide (SiO ₂ ), magnesium oxide (MgO), and calcium oxide (CaO). Add and mix to form a slurry. From this, a plurality of ceramic green sheets are obtained by a tape forming technique such as a conventionally known doctor blade method or calendar roll method. Next, a metal paste obtained by adding and mixing an appropriate organic binder, plasticizer, solvent, etc. to a high melting point metal powder such as tungsten (W) or molybdenum (Mo) to this ceramic green sheet, a screen printing method, etc. The metallized wiring layer to be the line conductor 5c is formed in a predetermined pattern by printing and coating using the thick film forming technique. In addition, a metallized layer is preferably printed on the entire surface of the lower surface of the flat plate portion 5b so that the metal plate 10 can be brazed by Ag brazing or the like. Thereafter, a plurality of ceramic green sheets are laminated and fired at a temperature of about 1600 ° C. in a reducing atmosphere. In this way, the line conductor 5c matched with the characteristic impedance is formed at the input / output terminal 5.
[0024]
The metal plate 10 is substantially rectangular and is made of a metal such as an Fe-Ni-Co alloy or a Cu-W alloy. The metal plate 10 is formed into a predetermined shape by applying a conventionally known metal processing method such as rolling or punching to the ingot. Produced. A substantially rectangular parallelepiped base 8 on which the optical semiconductor element 2 made of AlN ceramics is placed is brazed to the tip of the inner surface of the optical semiconductor device on which the input / output terminal 5 of the metal plate 10 is placed. It is brazed by etc.
[0025]
The base 8 is preferably provided with a line conductor 8a made of W, Mo or the like on the main surface on which the optical semiconductor element 2 is placed. That is, the electrode of the optical semiconductor element 2 mounted on the base 8 is electrically connected to the tip of the line conductor 8a on the optical semiconductor element 2 side via the bonding wire 9 or the like, and the line conductor 8a and the line conductor 5c are connected. Are electrically connected via a bonding wire 9 or the like, so that the electrode of the optical semiconductor element 2 is not directly connected to the line conductor 5c of the input / output terminal 5, but is connected to the line conductor 8a of the base 8. By doing so, the length of the bonding wire 9 can be shortened, and the transmission loss of the high frequency signal by the bonding wire 9 can be minimized. In addition, a metallized layer made of W, Mo, or the like is printed on the entire surface of the other main surface of the base 8 in order to braze the metal plate 10.
[0026]
Since the base 8 is made of AlN ceramics, the heat generated by the optical semiconductor element 2 during operation can be efficiently transmitted to the metal plate 10 and efficiently radiated from the portion of the metal plate 10 outside the optical semiconductor device to the outside. Therefore, the heat of the optical semiconductor element 2 can be efficiently radiated to the outside, the temperature of the optical semiconductor element 2 can be prevented from being increased due to heat accumulation, and the optical semiconductor element 2 can be operated normally.
[0027]
The input / output terminal 5 may be made of AlN ceramics and formed integrally with the base 8. However, since the production cost of the input / output terminals 5 is higher than that of Al ₂ O ₃ ceramics, the input / output terminals 5 In order to efficiently dissipate the heat of the semiconductor element 2 to the outside, it is sufficient that only the base 8 is made of AlN ceramics.
[0028]
Further, on the outer peripheral portion of the upper main surface of the base body 1 is provided with a cylindrical lid body 3 in which a through hole 3b is formed at a substantially central portion of the upper end surface 3a and the lower end is opened. The lower end 3c of the lid 3 is airtightly joined to the base body 1 by soldering or welding with solder such as lead (Pb) -tin (Sn) solder. The lower end 3c has a bowl shape as shown in FIG. 1 in order to increase the bonding area with the base 1 and improve the airtight reliability inside the container constituted by the base 1 and the lid 3. preferable.
[0029]
The lid 3 has a cylindrical shape with a cross-sectional shape (transverse cross-sectional shape) such as a circle or a rectangle, and is conventionally known metal processing such as rolling or punching a metal ingot such as an Fe-Ni-Co alloy. It is manufactured in a predetermined shape by applying the method. The lid 3 may be one in which the cylindrical portion and the upper end surface 3a are individually manufactured and joined by brazing, soldering, welding, or the like.
[0030]
The translucent member 4 is airtightly bonded to the lid 3 by glass bonding or soldering around the upper end surface 3a side opening of the through hole 3b so as to close the through hole 3b. The translucent member 4 has a disk shape, a lens shape, a spherical shape, a hemispherical shape, or the like made of glass, sapphire, or the like. In the case of a hemispherical part, it is joined to the lid 3 at the outer peripheral part of the flat part.
[0031]
The optical fiber 6 is fixed to the upper end surface of a substantially cylindrical metal fixing member 7 made of a metal such as an Fe—Ni—Co alloy, and the lower end surface of the metal fixing member 7 is the outer periphery of the lid 3. It is joined to the surface by welding such as laser welding. When the optical fiber 6 is fixed above the translucent member 4 via the metal fixing member 7, an optical semiconductor device as a product is obtained. As a result, optical signals can be exchanged between the optical semiconductor element 2 accommodated inside and the outside via the optical fiber 6.
[0032]
In the present invention, the translucent member 4 is preferably joined around the opening on the upper end surface 3a side of the through-hole 3b. In this case, the following points are advantageous. That is, heat when the metal fixing member 7 is welded to the outer periphery of the lid 3 is locally applied to the lid 3, and tensile stress due to thermal expansion is applied to the joint surface of the lid 3 with the translucent member 4. If applied, the translucent member 4 is easily peeled off from the lid 3. However, since the optical semiconductor device is airtight from the outside to make the inside airtight, the translucent member 4 is pressed against the lid 3 by the atmospheric pressure. It becomes difficult to peel off. On the other hand, when the translucent member 4 is joined to the periphery of the opening on the back surface side of the upper end surface 3a of the through hole 3b, a tensile stress that causes the translucent member 4 to be peeled off by a stress due to thermal expansion and a pressure due to atmospheric pressure. However, the translucent member 4 is easily detached from the lid 3.
[0033]
In the present invention, the upper surface of the flat plate portion 5b of the input / output terminal 5 and the mounting surface of the optical semiconductor element 2 of the base 8 are preferably substantially flush. In this case, the length of the bonding wire 9 connecting the line conductor 5c and the line conductor 8a is minimized, and the inductance is also reduced. Moreover, it is also possible to connect with a plate-shaped metal piece without using the bonding wire 9. In the case of a plate-shaped metal piece, the inductance is further reduced, and the impedance can be adjusted in the metal piece.
[0034]
The optical semiconductor device of the present invention is an optical semiconductor device as a product by electrically connecting the electrodes of the optical semiconductor element 2 to an external electric circuit. This optical semiconductor device excites light to the optical semiconductor element 2 by an electrical signal supplied from an external electrical circuit, transmits this light in the order of the translucent member 4 and the optical fiber 6, and passes through the optical fiber 6 to the outside. By transmitting to, it functions as an optical semiconductor device used for high-speed optical communication or the like.
[0035]
Note that the present invention is not limited to the above-described embodiment, and various modifications may be made without departing from the scope of the present invention.
[0036]
【The invention's effect】
The present invention is a plate-shaped metal base, and a cylindrical shape having a through hole formed at a substantially central portion of the upper end surface and an open lower end, and a lower end at the outer peripheral portion of the upper main surface of the base. In the through hole formed so as to penetrate between the upper and lower main surfaces of the base body, comprising a joined metal lid and a translucent member joined around the upper end surface side opening of the through hole, An input / output terminal consisting of a dielectric plate that has a line conductor formed from one side to the opposite side on the upper surface, and a vertical wall that is joined to the upper surface of the plate portion with the line conductor interposed therebetween is metal. The optical semiconductor element is placed in a state where it is placed on the plate, and the optical semiconductor element is placed on the tip inside the optical semiconductor device of the metal plate via a base made of aluminum nitride ceramics. A large number of line conductors are formed on the top surface of the flat plate with fine spacing. As a result, signal input / output of not only the optical semiconductor element and the monitoring PD but also a driver IC for driving the optical semiconductor element can be performed at the input / output terminals. A driver IC or the like can also be mounted. As described above, since the driver IC and the like that need to be electrically connected to the optical semiconductor device via the external electric circuit can be mounted and integrated in the optical semiconductor device, the entire device for driving the optical semiconductor element can be integrated. Can be downsized.
[0037]
Moreover, even if the signal transmitted through the input / output terminal becomes a high frequency, the high-frequency signal can be transmitted efficiently, and the airtight reliability of the input / output terminal portion is improved.
[0038]
Furthermore, since the input / output terminals are mounted on the metal plate and the base is joined to the tip of the metal plate inside the optical semiconductor device, the input / output terminals and the metal plate can be fitted to the base, so that the base can be easily lighted. A base plate and a metal plate made of AlN ceramics with high thermal conductivity, which can be bonded into a semiconductor device and can emit an optical signal emitted from the end face of the optical semiconductor element in the direction of the optical fiber. Can efficiently dissipate heat to the outside. As a result, the workability of the mounting operation of the optical semiconductor element is improved, the heat of the optical semiconductor element can be efficiently radiated to the outside, and the temperature of the optical semiconductor element is prevented from being increased by storing heat in the optical semiconductor element, thereby making the optical semiconductor element normal Can be activated.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view showing an example of an embodiment of an optical semiconductor device of the present invention.
FIG. 2 is a cross-sectional view of a conventional optical semiconductor device.
[Explanation of symbols]
1: Base 1a: Through hole 2: Optical semiconductor element 3: Cover 3a: Upper end surface 3b: Through hole 4: Translucent member 5: Input / output terminal 5a: Standing wall portion 5b: Flat plate portion 5c: Line conductor 8: Base Table 10: Metal plate

Claims

A metal base having a flat plate shape and a metal having a through-hole formed at a substantially central portion of the upper end surface and having a lower end opened, and a lower end joined to the outer peripheral portion of the upper main surface of the base body A through hole formed so as to penetrate between the upper and lower main surfaces of the base body in an optical semiconductor device comprising a lid made of light and a translucent member bonded around the upper end surface side opening of the through hole In addition, a flat plate portion made of a dielectric having a line conductor formed from one side to the other side opposite to the upper surface, and a standing wall portion made of a dielectric bonded to the upper surface of the flat plate portion with the line conductor interposed therebetween. The output terminal is fitted in a state of being mounted on a metal plate, and the optical semiconductor element is mounted on the tip of the metal plate inside the optical semiconductor device via a base made of aluminum nitride ceramics. An optical semiconductor device.