【０００１】
【発明の属する技術分野】
本発明は、光半導体素子を収容するための光半導体素子収納用パッケージおよび光半導体装置に関し、特に外部電気回路基板への実装構造を改良したものに関する。
【０００２】
【従来の技術】
従来の光半導体素子を収納するための光半導体素子収納用パッケージ（以下、単にパッケージともいう）を図４，図５に示す。図４はパッケージの平面図、図５は図４のＢ−Ｂ’線における断面図である。これらの図において、２１は略直方体の基体、２２は枠体、２３は光ファイバ固定部材（以下、固定部材ともいう）、２５は蓋体を示し、これら基体２１、枠体２２および蓋体２５とで、内部空間に光半導体素子３０を収容する容器が基本的に構成される。
【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）焼結材等の金属から成り、その上側主面の中央部には、半導体レーザ（ＬＤ），フォトダイオード（ＰＤ）等の光半導体素子３０を載置固定するための載置部２１ａが設けられる。また、基体２１の四隅を同一面でもって外側に延出して設けられた延出部に貫通孔２１ｃが形成されて成るネジ取付部２１ｂが設けられている。この基体２１は、貫通孔２１ｃにネジを通して外部電気回路基板にネジ止めして固定される。
【０００４】
基体２１の上側主面の外周部には、載置部２１ａを囲繞するようにして接合され、側部に貫通孔２２ａが形成された枠体２２が立設されている。この枠体２２は、基体２１と同様にＦｅ−Ｎｉ−Ｃｏ合金やＣｕ−Ｗ焼結材等の金属から成り、基体２１と一体成形される、または基体２１に銀（Ａｇ）ロウ等のロウ材を介してロウ付けされる、またはシーム溶接法等の溶接法により接合されることによって、基体２１の上側主面の外周部に立設される。
【０００５】
また、枠体２２の側部には、固定部材２３が貫通孔２２ａに嵌着されて取り付けられている。固定部材２３は、光ファイバ２６を枠体２２の側部に固定するための筒状の部材であり、Ｆｅ−Ｎｉ−Ｃｏ合金やステンレス鋼（ＳＵＳ）等の金属から成り、固定部材２３には縦方向に形成された貫通孔２３ａが設けられており、固定部材２３の外周面が枠体２２の貫通孔２２ａの内面にロウ材を介して嵌着接合される。
【０００６】
このような構成のパッケージの載置部２１ａに光半導体素子３０をペルチェ素子や回路基板等の基台３１に搭載された状態で載置固定した後、枠体２２の側部または基体２１に設けられた、パッケージの内外の導電路として機能する入出力端子（図示せず）の枠体２２内側の電極と光半導体素子３０の電極とをボンディングワイヤで電気的に接続する。そして、ホルダー２７に固定された光ファイバ２６を固定部材２３に挿入し、ホルダー２７を固定部材２３に溶接固定することにより光ファイバ２６の光入出力端面と光半導体素子３０の光入出力端面とを光結合させる。しかる後、枠体２２の上面にＦｅ−Ｎｉ−Ｃｏ合金等から成る蓋体２５をシーム溶接法等の溶接法により接合して光半導体素子３０を気密に封止することによって、製品としての光半導体装置が完成する。
【０００７】
この光半導体装置は、ネジ取付部２１ｂの貫通孔２１ｃにネジを通して基体２１を外部電気回路基板（図示せず）にネジ止め固定し、入出力端子（図示せず）の枠体２２の外側の電極と外部電気回路とを電気的に接続した後、外部電気回路から電気信号によって光半導体素子３０で光を励起させ、この光を光ファイバ２６を介して外部に伝送することによって、または、外部から光ファイバ２６を通って伝送してきた光信号を、光半導体素子３０に受光させて光信号を電気信号に変換することによって作動し、高速光通信等に使用される。
【０００８】
しかしながら、このような光半導体装置は、貫通孔２１ｃにネジを挿入して外部電気回路基板にネジ止め固定する際、ネジの締め付けによりネジ取付部２１ｂに応力が発生し、この応力が基体２１や枠体２２に伝わってパッケージに歪みが生じ、その結果、光ファイバ２６と光半導体素子３０との光軸がずれて光結合効率が劣化するという問題点を有していた。
【０００９】
このような問題点を解決するため、ネジ取付部２１ｂを基体２１と別体とし、基体２１よりも縦弾性係数の低い材質、例えば、Ｃｕ，Ｃｕ合金，アルミニウム（Ａｌ），Ａｌ合金等で形成し、基体２１にＡｇロウ付けした構成が提案されている（例えば、下記の特許文献１参照）。これにより、パッケージをネジ止め固定する際、ネジ取付部２１ｂをネジで締め付けても、ネジ取付部２１ｂが主に変形して基体２１の変形が抑えられ、光半導体素子３０と光ファイバ２６との光結合効率の低下を抑制することができる。
【００１０】
【特許文献１】
特開平６−８２６５９号公報
【００１１】
【発明が解決しようとする課題】
しかしながら、上記特許文献１に示されるパッケージは、光半導体素子３０の動作により大量の熱が発生すると、その熱によって基体２１が熱膨張し、枠体２２との接合部において応力が発生してパッケージに歪みが生じ、その結果、光ファイバ２６と光半導体素子３０との光軸がずれて光結合効率が劣化するという問題点を有していた。
【００１２】
また、パッケージをネジ止め固定する際、ネジ取付部２１ｂをネジで締め付けても、ネジ取付部２１ｂが主に変形して基体２１の変形が抑えられるものの、ネジ取付部２１ｂと基体２１との接合部には応力が集中し易く、その応力によりネジ取付部２１ｂと基体２１との接合部において剥離が生じ、パッケージが破損するという問題点をも有していた。
【００１３】
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、光半導体素子収納用パッケージのネジ止めにより、または、光半導体素子の作動時に発生する熱により、光半導体素子収納用パッケージに歪が生じるのを有効に抑制し、ＬＤ，ＰＤ等の光半導体素子の光入出力端面と光ファイバの光入出力端面との間における光信号の授受を正常に維持させ、光結合効率の優れた光半導体素子収納用パッケージおよび光半導体装置を提供することにある。
【００１４】
【課題を解決するための手段】
本発明の光半導体素子収納用パッケージは、中央部に貫通穴を有し、四隅にネジ取付部がそれぞれ形成された略直方体の金属製の基体と、前記貫通穴に嵌着された、上面に光半導体素子を載置固定する載置用基板と、前記基体の上側主面の外周部で前記ネジ取付部よりも内側に前記貫通穴を囲繞するように接合され、側部に貫通孔が形成された金属製の枠体と、前記貫通孔に嵌着されるかまたは前記貫通孔の前記枠体外側の開口の周囲に一端が接合された筒状の光ファイバ固定部材とを具備しており、前記ネジ取付部および前記載置用基板の厚みが前記基体の前記枠体が接合される部位よりも薄く、前記載置用基板の縦弾性係数が前記基体の縦弾性係数よりも大きいことを特徴とする。
【００１５】
本発明の光半導体素子収納用パッケージは、中央部に貫通穴を有し、四隅にネジ取付部がそれぞれ形成された略直方体の金属製の基体と、貫通穴に嵌着された、上面に光半導体素子を載置固定する載置用基板と、基体の上側主面の外周部でネジ取付部よりも内側に貫通穴を囲繞するように接合され、側部に貫通孔が形成された金属製の枠体と、貫通孔に嵌着されるかまたは貫通孔の枠体外側の開口の周囲に一端が接合された筒状の光ファイバ固定部材とを具備しており、ネジ取付部および載置用基板の厚みが基体の枠体が接合される部位よりも薄く、載置用基板の縦弾性係数が基体の縦弾性係数よりも大きいことから、ネジ取付部にネジを挿入し光半導体素子収納用パッケージを外部電気回路基板にネジ止めする際に、ネジの締め付けによりネジ取付部に応力が発生したとしても、縦弾性係数が載置用基板よりも小さい基体のネジ取付部が変形することにより載置用基板に歪を生じることなく応力を緩和することができ、載置用基板に搭載された光半導体素子の位置精度を良好に維持することができる。
【００１６】
また、光半導体素子の動作により大量の熱が発生し、その熱によって載置用基板が熱膨張したとしても、縦弾性係数が載置用基板よりも小さな基体が載置用基板の熱膨張による応力を吸収することができ、枠体と基体との接合部に応力が伝達されるのを抑制して光半導体素子収納用パッケージが歪むのを有効に抑制することができる。
【００１７】
さらに、載置用基板が基体の枠体が接合している部位よりも薄いことにより、基体と載置用基板との接合面積が小さくなり、載置用基板が熱膨張しても基体に加わる歪が小さくなって基体の変形が少なくなる。即ち、載置用基板から応力が枠体へ伝達されるのを有効に抑制することができる。また、光半導体素子の熱を載置用基板の下方の外部電気回路基板や放熱板に効率よく伝熱させることができ、放熱性が向上する。
【００１８】
また、ネジ取付部と基体の枠体が接合している部位との厚み差により段差が形成され、この段差においてネジ取付部が変形し易くなることから、基体の枠体が接合している部位に歪みが生じ難く、枠体へ応力が伝達するのを有効に抑制することができる。また、ネジ取付部と基体の枠体が接合している部位とが一体で形成されているため、強度の弱い接合部が存在せず、光半導体素子収納用パッケージが破損することもない。
【００１９】
これらの結果、光半導体素子収納用パッケージを外部電気回路基板にネジ止め固定する際や、収容する光半導体素子の作動により熱が発生した際に、応力を緩和して光半導体素子収納用パッケージの歪や破損を有効に抑制し、光半導体素子の光入出力端面と光ファイバの光入出力端面との間における光信号の授受を正常に維持させ、光結合効率の優れたものとすることができる。
【００２０】
本発明の光半導体装置は、上記本発明の光半導体素子収納用パッケージと、前記光ファイバ固定部材に挿入され固定された光ファイバと、該光ファイバに光学的に結合するように前記載置用基板に載置固定された光半導体素子と、前記枠体の上面に接合された蓋体とを具備したことを特徴とする。
【００２１】
本発明の光半導体装置は、上記の構成により、上記本発明の光半導体素子収納用パッケージを用いた信頼性の高いものとなる。
【００２２】
【発明の実施の形態】
本発明の光半導体素子収納用パッケージについて以下に詳細に説明する。図１は本発明のパッケージについて実施の形態の一例を示す平面図、図２は図１のＡ−Ａ’線における断面図である。これらの図において、１は基体、２は枠体、３は固定部材、５は蓋体を示し、これら基体１、枠体２および蓋体５とで、内部に光半導体素子１０を収容する容器が基本的に構成される。
【００２３】
本発明のパッケージは、中央部に貫通穴１ｄを有し、四隅にネジ取付部１ｂがそれぞれ形成された略直方体の金属製の基体１と、貫通穴１ｄに嵌着された、上面に光半導体素子１０を載置固定する載置用基板１−Ａと、基体１の上側主面の外周部でネジ取付部１ｂよりも内側に貫通穴１ｄを囲繞するように接合され、側部に貫通孔２ａが形成された金属製の枠体２と、貫通孔２ａに嵌着されるかまたは貫通孔２ａの枠体２外側の開口の周囲に一端が接合された筒状の固定部材３とを具備しており、ネジ取付部１ｂおよび載置用基板１−Ａの厚みが基体１の枠体２が接合される部位よりも薄く、載置用基板１−Ａの縦弾性係数が基体１の縦弾性係数よりも大きくなっている。
【００２４】
基体１はＣｕ，Ａｌ，Ａｇ等の金属やこれらの合金から成り、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。基体１の四隅には外側に延出したネジ取付部１ｂが形成されており、ネジ取付部１ｂにはネジ挿入用の貫通孔１ｃが形成されている。
【００２５】
基体１の枠体２が接合される部位の厚みｈ２は、ネジ取付部１ｂの厚みｈ１に対してｈ２＞ｈ１となっている。これにより、ネジ取付部１ｂと基体１の枠体２が接合している部位との厚み差により段差が形成され、この段差においてネジ取付部１ｂが変形し易くなることから、基体１の枠体２が接合している部位に歪みが生じ難く、枠体２へ応力が伝達するのを有効に抑制することができる。また、ネジ取付部１ｂと基体１の枠体２が接合している部位とが一体で形成されているため、強度の弱い接合部が存在せず、パッケージが破損することもない。
【００２６】
ｈ２は好ましくは１．５×ｈ１≦ｈ２≦３×ｈ１であるのがよい。ｈ２＜１．５×ｈ１である場合、ｈ１とｈ２との厚み差が小さすぎるため、特に平坦性に劣る外部電気回路基板にパッケージをネジ止め固定した際にネジ取付部１ｂの変形が非常に大きくなると、基体１の枠体２が接合されている部位までもが変形し易くなり、枠体２が歪み易くなる。また、ｈ２＞３×ｈ１であると、基体１の枠体２が接合している部位が厚くなりすぎ、光半導体素子１０の位置を高くして光ファイバ６と同じにする必要があり、パッケージが大型化する。
【００２７】
ネジ取付部１ｂの平面視形状は、図１に示すように、ネジ取付部１ｂが存在する基体１の対向する２つの変部をそれぞれ枠体２よりも外側に延出させたものでもよく、図３に示すように、基体１の四隅をそれぞれ枠体２よりも外側に張り出すように延出させ、各延出部に１個ずつ貫通孔１ｃを形成したものでもよい。
【００２８】
また、枠体２の外面は、基体１とネジ取付部１ｂとの段差部Ｄ（図２）よりも内側にあって、枠体２の外面と段差部Ｄの間の距離ｄは０ｍｍ≦ｄ≦３ｍｍであるのがよい。これにより、ネジ取付部１ｂにネジを挿入して基体１を外部電気回路基板にネジ止め固定しても、枠体２よりも外側でネジ取付部１ｂが変形することにより枠体２に歪みが加わるのを有効に防止できる。ｄ＞３ｍｍの場合、基体１が必要以上に大型化し、近時の小型化傾向に適さないものとなる。一方、枠体２の外面が段差部Ｄよりも外側にある場合、ネジ取付部１ｂの変形によりネジ取付部１ｂが枠体２に接触して枠体２が歪み易くなる。また、枠体２と基体１との接合面積が小さくなり、枠体２と基体１との接合強度も小さくなり易い。
【００２９】
本発明の載置用基板１−Ａは、その厚みが基体１の枠体２が接合される部位よりも薄く、載置用基板１−Ａの縦弾性係数が基体１の縦弾性係数よりも大きくなっている。これにより、ネジ取付部１ｂにネジを挿入しパッケージを外部電気回路基板にネジ止めする際に、ネジの締め付けによりネジ取付部１ｂに応力が発生したとしても、縦弾性係数が載置用基板１−Ａよりも小さい基体１のネジ取付部１ｂが変形することにより載置用基板１−Ａに歪を生じることなく応力を緩和することができ、載置用基板１−Ａに搭載された光半導体素子１０の位置精度を良好に維持することができる。
【００３０】
また、光半導体素子１０の作動により大量の熱が発生し、その熱によって載置用基板１−Ａが熱膨張したとしても、縦弾性係数が載置用基板１−Ａよりも小さな基体１が載置用基板１−Ａの熱膨張による応力を吸収することができ、枠体２と基体１との接合部に応力が伝達されるのを抑制してパッケージが歪むのを有効に抑制することができる。
【００３１】
さらに、載置用基板１−Ａが基体１の枠体２が接合している部位よりも薄いことにより、基体１と載置用基板１−Ａとの接合面積が小さくなり、載置用基板１−Ａが熱膨張しても基体１に加わる歪が小さくなって基体１の変形が少なくなる。即ち、載置用基板１−Ａから応力が枠体２へ伝達されるのを有効に抑制することができる。また、光半導体素子１０の熱を載置用基板１−Ａの下方の外部電気回路基板や放熱板に効率よく伝熱させることができ、放熱性が向上する。
【００３２】
このような載置用基板１−Ａは、基体１よりも縦弾性係数の大きな材料、例えばＦｅ−Ｎｉ−Ｃｏ合金やＣｕ−Ｗの焼結材等から成り、射出成形や切削加工等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。載置用基板１−ＡはＡｇロウ等でロウ付けすることによって基体１の貫通穴１ｄに嵌着される。
【００３３】
そして、載置用基板１−Ａの上面の載置部１ａには、ＬＤ，ＰＤ等の光半導体素子１０が載置固定される。載置用基板１−Ａは、光半導体素子１０が作動時に発する熱を外部に放熱させる放熱板としての役割も果たす。なお、光半導体素子１０は、作動時に発生する熱を効率よく載置用基板１−Ａを介して外部へ放熱させるために、ペルチェ素子や回路基板等の基台１１に搭載された状態で載置部１ａに載置固定されてもよい。
【００３４】
載置用基板１−Ａの厚みｈ３は、基体１の枠体２が接合される部位の厚みｈ２に対してｈ３＜ｈ２となっている。これにより、基体１と載置用基板１−Ａとの接合面積が小さくなり、載置用基板１−Ａが熱膨張しても基体１に加わる歪が小さくなって基体１の変形が少なくなる。即ち、載置用基板１−Ａから応力が枠体２へ伝達されるのを有効に抑制することができる。また、光半導体素子１０の熱を載置用基板１−Ａの下方の外部電気回路基板や放熱板に効率よく伝熱させることができ、放熱性が向上する。さらに、載置用基板１−Ａを薄くすることができることから、載置用基板１−Ａ、基体１および枠体２から形成される容器の容積を十分に確保することができ、パッケージの小型化が可能となる。
【００３５】
ｈ３は好ましくは０．３×ｈ２≦ｈ３≦０．９×ｈ２であるのがよい。ｈ３＜０．３×ｈ２である場合、載置用基板１−Ａが薄くなって強度が小さくなり、載置用基板１−Ａが歪み易くなる。また、ｈ３＞０．９×ｈ２であると、載置用基板１−Ａと基体１との接合面積が大きくなり、光半導体素子１０の作動で発生した熱によって載置用基板１−Ａが熱膨張した際、基体１が大きく変形し易くなり、その応力が枠体２に伝達され易くなる。
【００３６】
また、ｈ３はｈ１＜ｈ３≦０．９×ｈ２であるのがよい。これにより、載置用基板１−Ａを変形し難くすることができ、基体１が大きく変形した場合でも、載置部１ａに搭載された光半導体素子１０と光ファイバ６との位置精度を良好に維持し、これらの光結合効率の低下を有効に抑制することができる。
【００３７】
さらに、載置用基板１−Ａは載置部１ａよりも外周部が厚くなっているのがよい。これにより、載置用基板１−Ａの強度を大きくして変形し難くすることができるとともに、載置部１ａは薄くなっているので光半導体素子１０で発生した熱を効率良く外部電気回路基板や放熱板に伝熱させることができる。
【００３８】
なお、基体１、載置用基板１−Ａの表面には、酸化腐食の防止や光半導体素子１０の載置固定を良好にするために、厚さ０．５〜９μｍのＮｉ層や厚さ０．５〜５μｍの金（Ａｕ）層からなる金属層をめっき法等により被着させておくとよい。
【００３９】
枠体２は、基体１の上側主面の外周部でネジ取付部１ｂよりも内側に貫通穴１ｄを囲繞するように接合され、側部に貫通孔２ａが形成されており、平面視形状が略四角形の枠状体である。
【００４０】
枠体２は、基体１および載置用基板１−Ａとともにその内側に光半導体素子１０を収容する空所を形成するとともに、その側部の貫通孔２ａに嵌着されるかまたは貫通孔２ａの枠体２外側の開口の周囲に一端が接合された筒状の固定部材３を介して光ファイバ６を支持固定する。
【００４１】
このような枠体２は、載置用基板１−Ａと同様にＦｅ−Ｎｉ−Ｃｏ合金やＣｕ−Ｗの焼結材等から成り、基体１にＡｇロウ等のロウ材を介してロウ付けされる、またはシーム溶接法等の溶接法により接合されることにより、基体１の上側主面の外周部に立設される。
【００４２】
固定部材３は、光ファイバ６を枠体２の側部に固定するための円筒状等の筒状の部材であり、Ｆｅ−Ｎｉ−Ｃｏ合金やステンレス鋼等の金属から成る。固定部材３は、軸方向に光ファイバ６を挿入するための貫通孔３ａが設けられており、枠体２の側部の貫通孔２ａの内面に外周面がロウ材を介して嵌着されるかまたは貫通孔２ａの枠体２外側の開口の周囲に一端がロウ材を介して接合されることにより、枠体２の側部に固定される。
【００４３】
ネジ取付部１ｂは、光ファイバ６が固定される貫通孔２ａが形成された枠体２の側部側およびこの側部に対向する枠体２の側部側に設けられているのがよい。これにより、パッケージを外部電気回路基板にネジ止め固定した際に発生する応力が、光ファイバ６が固定されている枠体２の側部に加わるのを抑制することができる。即ち、互いに逆の方向に延出した２つのネジ取付部１ｂの間に位置する部分において基体１の曲げ応力が最も大きくなり易いのに対し、枠体３の同じ側部側にある２つのネジ取付部１ｂの間に位置する部分においては基体１の曲げ応力は小さく、この曲げ応力の小さい部分に対応する枠体２の側部で光ファイバ６を固定することにより、光ファイバ６の位置がずれるのを有効に抑制することができる。
【００４４】
また、貫通孔１ｃの平面視形状は、図１に示すような円形である必要はなく、四角形や半円形等であってもよい。
【００４５】
本発明の光半導体装置は、上記構成のパッケージと、固定部材３に挿入され固定された光ファイバ６と、光ファイバ６に光学的に結合するように載置用基板１−Ａに載置された光半導体素子１０と、枠体２の上面に接合された蓋体５とを具備している。
【００４６】
このような光半導体装置は以下のようにして作製される。先ず、上記構成のパッケージに光半導体素子１０をペルチェ素子や回路基板等の基台１１を介して載置部１ａに載置固定した後、光半導体素子１０の電極と、枠体２の側部または基体１に設けられた、パッケージの内外の導電路として機能する入出力端子（図示せず）の枠体２内側の電極とを、ボンディングワイヤで電気的に接続し、枠体２の上面にＦｅ−Ｎｉ−Ｃｏ合金等の金属，セラミックス，樹脂等から成る蓋体５をロウ付け法やシームウエルド法等の溶接法で接合することにより、光半導体素子１０を気密に封止する。そして、光ファイバ６が挿通固定された枠状や筒状の金属製のホルダー７を、光半導体素子１０の光入出力端面と光ファイバ６の光入出力端面とが対向し光結合するようにして固定部材３の枠体２外側の一端に溶接することにより、光半導体装置が作製される。
【００４７】
本発明の光半導体装置は、ネジ取付部１ｂで外部電気回路基板にネジ止め固定され、入出力端子の枠体２外側の電極にリード端子やリボン線の一端をロウ付けし、リード端子やリボン線の他端を外部電気回路に接続することにより、光半導体装置内部に収納した光半導体素子１０が外部電気回路に電気的に接続され、光半導体素子１０が高周波信号で作動することとなる。
【００４８】
このような光半導体装置は、外部電気回路から供給される駆動信号によって光半導体素子１０を光励起させ、励起したレーザ光等の光信号を光ファイバ６に入力させるとともに光ファイバ６内を伝送させることによって、または、外部から光ファイバ６を通って伝送してきた光信号を光半導体素子１０に受光させて光信号を電気信号に変換することによって、大容量の情報を高速に伝送できる光電変換装置として機能し、光通信分野等に多く用いられる。
【００４９】
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種々の変更を施すことは可能である。例えば、固定部材３は貫通孔２ａの枠体２外側開口の周囲に一端がロウ付けまたは溶接されてもよく、これにより貫通孔２ａの内面に固定部材３の外周面を嵌着させる必要がなくなるため、貫通孔２ａの内径寸法および固定部材３の外形寸法の精度を比較的粗くすることができ、貫通孔２ａや固定部材３の加工が容易になり作業効率が向上する。
【００５０】
【実施例】
本発明の光半導体素子収納用パッケージの実施例を以下に説明する。
【００５１】
図１の本発明のパッケージのサンプルを以下のようにして作製した。Ｆｅ−Ｎｉ−Ｃｏ合金（縦弾性係数：１２８ＧＰａ）からなる縦２１ｍｍ×横１３ｍｍで厚さが１．８ｍｍの直方体からなり、その中央部に縦９．５ｍｍ×横７．５ｍｍの貫通穴１ｄをもつ基体１を用意し、その四隅に種々の厚みのネジ取り付け部１ｂ（表１参照）を形成した。
【００５２】
そして、Ｆｅ−Ｎｉ−Ｃｏ合金からなり縦２１ｍｍ×横１３ｍｍ×高さ７ｍｍで厚さ１ｍｍの枠体２を用意した。
【００５３】
さらに、Ｃｕ−Ｗの焼結体（縦弾性係数：２６５ＧＰａ）からなる縦９．５ｍｍ×横７．５ｍｍ×高さ１．５ｍｍの載置用基板１−Ａを貫通穴１ｄに嵌め込み、基体１、枠体２および載置用基板１−ＡをＡｇ−Ｃｕロウ（融点７８０℃）で接合し、これらを常温（２５℃）まで均一に冷却することによりパッケージを作製した（サンプルＰ１〜Ｐ７）。
【００５４】
これらのサンプルＰ１〜Ｐ７を上面が平坦な外部回路基板にネジ止めした際の、載置用基板中心部の厚み方向の歪によって発生した変位量を有限要素法による解析によって求めた。これらの評価結果を表１に示す。
【００５５】
【表１】
【００５６】
表１に示した結果より、本発明のサンプルにおける載置用基板の中心部に発生する変位は、ネジ取付け部の厚みを基体１の枠体が接合される部位よりも薄くすることにより、４０μｍ以下の値に低減させることができ、本発明のパッケージが光ファイバ６と光半導体素子１０との光軸ずれを抑制するのに有効であることが判った。
【００５７】
特に、ネジ取付部１ｂの厚さを基体１の厚さの２／３以下とすることにより、変位を２０μｍ以下とすることができ、光ファイバ６と光半導体素子１０との光軸ずれ防止に非常に有効であることが判った。
【００５８】
なお、本発明は以上の実施の形態の例および実施例に限定されるものではなく、本発明の要旨を逸脱しない範囲内で種々の変更を施すことは何等支障ない。
【００５９】
【発明の効果】
本発明の光半導体素子収納用パッケージは、中央部に貫通穴を有し、四隅にネジ取付部がそれぞれ形成された略直方体の金属製の基体と、貫通穴に嵌着された、上面に光半導体素子を載置固定する載置用基板と、基体の上側主面の外周部でネジ取付部よりも内側に貫通穴を囲繞するように接合され、側部に貫通孔が形成された金属製の枠体と、貫通孔に嵌着されるかまたは貫通孔の枠体外側の開口の周囲に一端が接合された筒状の光ファイバ固定部材とを具備しており、ネジ取付部および載置用基板の厚みが基体の枠体が接合される部位よりも薄く、載置用基板の縦弾性係数が基体の縦弾性係数よりも大きいことから、ネジ取付部にネジを挿入し光半導体素子収納用パッケージを外部電気回路基板にネジ止めする際に、ネジの締め付けによりネジ取付部に応力が発生したとしても、縦弾性係数が載置用基板よりも小さい基体のネジ取付部が変形することにより載置用基板に歪を生じることなく応力を緩和することができ、載置用基板に搭載された光半導体素子の位置精度を良好に維持することができる。
【００６０】
また、光半導体素子の動作により大量の熱が発生し、その熱によって載置用基板が熱膨張したとしても、縦弾性係数が載置用基板よりも小さな基体が載置用基板の熱膨張による応力を吸収することができ、枠体と基体との接合部に応力が伝達されるのを抑制して光半導体素子収納用パッケージが歪むのを有効に抑制することができる。
【００６１】
さらに、載置用基板が基体の枠体が接合している部位よりも薄いことにより、基体と載置用基板との接合面積が小さくなり、載置用基板が熱膨張しても基体に加わる歪が小さくなって基体の変形が少なくなる。即ち、載置用基板から応力が枠体へ伝達されるのを有効に抑制することができる。また、光半導体素子の熱を載置用基板の下方の外部電気回路基板や放熱板に効率よく伝熱させることができ、放熱性が向上する。
【００６２】
また、ネジ取付部と基体の枠体が接合している部位との厚み差により段差が形成され、この段差においてネジ取付部が変形し易くなることから、基体の枠体が接合している部位に歪みが生じ難く、枠体へ応力が伝達するのを有効に抑制することができる。また、ネジ取付部と基体の枠体が接合している部位とが一体で形成されているため、強度の弱い接合部が存在せず、光半導体素子収納用パッケージが破損することもない。
【００６３】
これらの結果、光半導体素子収納用パッケージを外部電気回路基板にネジ止め固定する際や、収容する光半導体素子の作動により熱が発生した際に、応力を緩和して光半導体素子収納用パッケージの歪や破損を有効に抑制し、光半導体素子の光入出力端面と光ファイバの光入出力端面との間における光信号の授受を正常に維持させ、光結合効率の優れたものとすることができる。
【００６４】
本発明の光半導体装置は、上記本発明の光半導体素子収納用パッケージと、光ファイバ固定部材に挿入され固定された光ファイバと、この光ファイバに光学的に結合するように載置用基板に載置された光半導体素子と、枠体の上面に接合された蓋体とを具備したことにより、上記本発明の光半導体素子収納用パッケージを用いた信頼性の高いものとなる。
【図面の簡単な説明】
【図１】本発明の光半導体素子収納用パッケージについて実施の形態の例を示す平面図である。
【図２】図１の光半導体素子収納用パッケージのＡ−Ａ’線における断面図である。
【図３】本発明の光半導体素子収納用パッケージについて実施の形態の他の例を示す平面図である。
【図４】従来の光半導体素子収納用パッケージの平面図である。
【図５】図４の光半導体素子収納用パッケージのＢ−Ｂ’線における断面図である。
【符号の説明】
１：基体
１ａ：載置部
１ｂ：ネジ取付部
１ｃ：貫通孔
１ｄ：貫通穴
１−Ａ：載置用基板
２：枠体
２ａ：貫通孔
３：光ファイバ固定部材
５：蓋体
６：光ファイバ
１０：光半導体素子[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an optical semiconductor element housing package for housing an optical semiconductor element and an optical semiconductor device, and more particularly to an optical semiconductor device having an improved mounting structure on an external electric circuit board.
[0002]
[Prior art]
FIGS. 4 and 5 show a conventional package for housing an optical semiconductor element (hereinafter simply referred to as a package) for housing an optical semiconductor element. FIG. 4 is a plan view of the package, and FIG. 5 is a sectional view taken along line BB ′ of FIG. In these figures, 21 is a substantially rectangular parallelepiped base, 22 is a frame, 23 is an optical fiber fixing member (hereinafter also referred to as a fixing member), 25 is a lid, and these base 21, frame 22 and lid 25 are shown. Thus, a container accommodating the optical semiconductor element 30 in the internal space is basically configured.
[0003]
The base 21 is made of a metal such as an iron (Fe) -nickel (Ni) -cobalt (Co) alloy or a copper (Cu) -tungsten (W) sintered material. A mounting portion 21a for mounting and fixing the optical semiconductor element 30 such as a (LD) and a photodiode (PD) is provided. Further, a screw mounting portion 21b is provided in which a through hole 21c is formed in an extending portion provided by extending the four corners of the base 21 outward on the same surface. The base 21 is fixed to the external electric circuit board by screwing through the through hole 21c.
[0004]
A frame 22 having a through hole 22a formed on the side thereof is provided upright on the outer peripheral portion of the upper main surface of the base 21 so as to surround the mounting portion 21a. The frame body 22 is made of a metal such as a Fe—Ni—Co alloy or a Cu—W sintered material similarly to the base body 21 and is formed integrally with the base body 21 or is formed on the base body 21 by a brazing material such as silver (Ag) brazing. By being brazed via a material or joined by a welding method such as a seam welding method, the base 21 is erected on the outer peripheral portion of the upper main surface.
[0005]
A fixing member 23 is attached to the side of the frame 22 by being fitted into the through-hole 22a. The fixing member 23 is a cylindrical member for fixing the optical fiber 26 to the side of the frame 22, and is made of a metal such as an Fe—Ni—Co alloy or stainless steel (SUS). A through hole 23a formed in a vertical direction is provided, and an outer peripheral surface of the fixing member 23 is fitted and joined to an inner surface of the through hole 22a of the frame 22 via a brazing material.
[0006]
After the optical semiconductor device 30 is mounted and fixed on the mounting portion 21a of the package having such a configuration while being mounted on the base 31 such as a Peltier device or a circuit board, the optical semiconductor device 30 is provided on the side portion of the frame 22 or the base 21. The electrodes inside the frame 22 of the input / output terminals (not shown) functioning as conductive paths inside and outside the package and the electrodes of the optical semiconductor element 30 are electrically connected by bonding wires. Then, the optical fiber 26 fixed to the holder 27 is inserted into the fixing member 23, and the holder 27 is fixed to the fixing member 23 by welding, so that the optical input / output end face of the optical fiber 26 and the optical input / output end face of the optical semiconductor element 30 are connected. Are optically coupled. Thereafter, a lid 25 made of an Fe—Ni—Co alloy or the like is joined to the upper surface of the frame 22 by a welding method such as a seam welding method to hermetically seal the optical semiconductor element 30, so that light as a product is obtained. The semiconductor device is completed.
[0007]
In this optical semiconductor device, the base 21 is screwed and fixed to an external electric circuit board (not shown) through a screw through the through hole 21c of the screw mounting portion 21b, and the outside of the frame 22 of the input / output terminal (not shown). After the electrodes are electrically connected to the external electric circuit, light is excited in the optical semiconductor element 30 by an electric signal from the external electric circuit, and the light is transmitted to the outside through the optical fiber 26, or The optical signal transmitted from the optical fiber 26 through the optical fiber 26 is received by the optical semiconductor element 30 to convert the optical signal into an electric signal, which is used for high-speed optical communication and the like.
[0008]
However, in such an optical semiconductor device, when a screw is inserted into the through hole 21c and fixed to the external electric circuit board with a screw, stress is generated in the screw mounting portion 21b due to the tightening of the screw, and the stress is generated by the base 21 or There is a problem in that the package is distorted by being transmitted to the frame 22, and as a result, the optical axis of the optical fiber 26 and the optical semiconductor element 30 are shifted, and the optical coupling efficiency is deteriorated.
[0009]
In order to solve such a problem, the screw mounting portion 21b is formed separately from the base 21, and is formed of a material having a lower longitudinal elastic modulus than the base 21, for example, Cu, Cu alloy, aluminum (Al), Al alloy, or the like. A configuration in which Ag is brazed to the base 21 has been proposed (for example, see Patent Document 1 below). Accordingly, when the package is screwed and fixed, even if the screw mounting portion 21b is tightened with a screw, the screw mounting portion 21b is mainly deformed and deformation of the base 21 is suppressed, so that the optical semiconductor element 30 and the optical fiber 26 A decrease in optical coupling efficiency can be suppressed.
[0010]
[Patent Document 1]
JP-A-6-82659
[0011]
[Problems to be solved by the invention]
However, in the package disclosed in Patent Document 1, when a large amount of heat is generated by the operation of the optical semiconductor element 30, the heat causes the base 21 to thermally expand and generate stress at a joint portion with the frame 22, thereby causing Of the optical fiber 26 and the optical semiconductor element 30 as a result, and the optical coupling efficiency is degraded.
[0012]
In addition, when the package is screwed and fixed, even if the screw mounting portion 21b is tightened with a screw, the screw mounting portion 21b is mainly deformed and deformation of the base 21 is suppressed. There is also a problem that the stress is easily concentrated on the portion, and the stress causes peeling at the joint portion between the screw mounting portion 21b and the base 21 to break the package.
[0013]
Accordingly, the present invention has been completed in view of the above problems, and has as its object to fix an optical semiconductor element housing by screwing the optical semiconductor element housing package or by heat generated during operation of the optical semiconductor element. It effectively suppresses the occurrence of distortion in the package, maintains the normal transmission and reception of optical signals between the optical input / output end faces of optical semiconductor elements such as LDs and PDs and the optical input / output end faces of optical fibers, and achieves optical coupling efficiency. It is an object of the present invention to provide an optical semiconductor element housing package and an optical semiconductor device excellent in the above.
[0014]
[Means for Solving the Problems]
The optical semiconductor element housing package of the present invention has a substantially rectangular parallelepiped metal base having a through hole in the center portion, and a screw attachment portion formed at each of the four corners, and an upper surface fitted in the through hole. A mounting substrate on which the optical semiconductor element is mounted and fixed, and an outer peripheral portion of the upper main surface of the base body, which is joined to the inside of the screw attachment portion so as to surround the through hole, and a through hole is formed in a side portion. Metal frame, and a cylindrical optical fiber fixing member fitted to the through-hole or joined at one end to the periphery of the opening of the through-hole outside the frame. The thickness of the screw mounting portion and the mounting substrate is thinner than a portion of the base body to which the frame is joined, and the longitudinal elastic coefficient of the mounting substrate is larger than the longitudinal elastic coefficient of the base body. Features.
[0015]
The optical semiconductor element housing package of the present invention has a substantially rectangular parallelepiped metal base having a through hole at the center and screw mounting portions formed at four corners, respectively, and an optical module on the upper surface fitted into the through hole. A mounting substrate on which a semiconductor element is mounted and fixed, and a metal formed on the outer peripheral portion of the upper main surface of the base so as to surround the through hole inside the screw mounting portion and form a through hole on the side portion. And a cylindrical optical fiber fixing member that is fitted into the through hole or that has one end joined to the periphery of the opening of the through hole outside the frame. The thickness of the mounting substrate is thinner than the portion where the frame of the base is joined, and the longitudinal elastic coefficient of the mounting substrate is larger than that of the base. Screw the external package to the external electric circuit board. Even if stress is generated in the mounting portion, the stress can be relieved without deforming the mounting substrate by deforming the screw mounting portion of the base having a smaller longitudinal elastic modulus than the mounting substrate, The positional accuracy of the optical semiconductor element mounted on the mounting substrate can be maintained satisfactorily.
[0016]
In addition, even if a large amount of heat is generated by the operation of the optical semiconductor element, and the mounting substrate thermally expands due to the heat, the base having a smaller longitudinal elastic modulus than the mounting substrate is caused by the thermal expansion of the mounting substrate. The stress can be absorbed, and the transmission of the stress to the joint between the frame and the base can be suppressed, so that the optical semiconductor element housing package can be effectively prevented from being distorted.
[0017]
Furthermore, since the mounting substrate is thinner than the portion where the frame of the base is bonded, the bonding area between the base and the mounting substrate is reduced, so that the mounting substrate is added to the base even when thermally expanded. The distortion is reduced and the deformation of the base is reduced. That is, transmission of stress from the mounting substrate to the frame body can be effectively suppressed. Further, the heat of the optical semiconductor element can be efficiently transmitted to the external electric circuit board and the heat radiating plate below the mounting substrate, so that the heat radiating property is improved.
[0018]
Also, a step is formed due to a thickness difference between the screw attachment portion and the portion where the frame of the base is joined, and the screw attachment portion is easily deformed at this step, so that the portion where the frame of the base is joined is formed. In this case, distortion is less likely to occur, and transmission of stress to the frame can be effectively suppressed. Further, since the screw attachment portion and the portion where the frame of the base is joined are formed integrally, there is no weak joint portion, and the package for housing the optical semiconductor element is not damaged.
[0019]
As a result, when the optical semiconductor element housing package is screwed and fixed to the external electric circuit board or when heat is generated by the operation of the housed optical semiconductor element, stress is relieved to reduce the stress of the optical semiconductor element housing package. It is necessary to effectively suppress distortion and breakage, maintain normal transmission and reception of optical signals between the optical input / output end face of the optical semiconductor element and the optical input / output end face of the optical fiber, and achieve excellent optical coupling efficiency. it can.
[0020]
The optical semiconductor device of the present invention includes the optical semiconductor element storage package of the present invention, an optical fiber inserted and fixed in the optical fiber fixing member, and an optical fiber that is optically coupled to the optical fiber. An optical semiconductor device mounted and fixed on a substrate and a lid joined to an upper surface of the frame are provided.
[0021]
With the above configuration, the optical semiconductor device of the present invention has high reliability using the optical semiconductor element housing package of the present invention.
[0022]
BEST MODE FOR CARRYING OUT THE INVENTION
The package for housing an optical semiconductor element of the present invention will be described in detail below. FIG. 1 is a plan view showing an example of an embodiment of the package of the present invention, and FIG. 2 is a cross-sectional view taken along line AA ′ of FIG. In these figures, reference numeral 1 denotes a base, 2 denotes a frame, 3 denotes a fixing member, and 5 denotes a lid. The base 1, the frame 2 and the lid 5 are containers for housing the optical semiconductor element 10 therein. Is basically configured.
[0023]
The package of the present invention has a substantially rectangular parallelepiped metal base 1 having a through hole 1d at the center and screw mounting portions 1b at four corners, respectively, and an optical semiconductor on the upper surface fitted into the through hole 1d. The mounting substrate 1-A on which the element 10 is mounted and fixed is joined to the outer peripheral portion of the upper main surface of the base 1 so as to surround the through hole 1d inside the screw mounting portion 1b, and the through hole is formed on the side. A metal frame 2 having a metal frame 2a formed therein, and a cylindrical fixing member 3 fitted to the through hole 2a or joined at one end to a periphery of an opening of the frame 2 outside the through hole 2a. The thickness of the screw mounting portion 1b and the thickness of the mounting substrate 1-A are thinner than the portion where the frame 2 of the base 1 is joined, and the longitudinal elastic coefficient of the mounting substrate 1-A is It is larger than the elastic modulus.
[0024]
The base 1 is made of a metal such as Cu, Al, or Ag or an alloy thereof, and is manufactured into a predetermined shape by subjecting the ingot to a conventionally known metal working method such as rolling or punching. At four corners of the base 1, a screw mounting portion 1b extending outward is formed, and the screw mounting portion 1b is formed with a through hole 1c for screw insertion.
[0025]
The thickness h2 of the portion of the base 1 to which the frame 2 is joined is h2> h1 with respect to the thickness h1 of the screw mounting portion 1b. As a result, a step is formed due to the thickness difference between the screw mounting portion 1b and the portion where the frame 2 of the base 1 is joined, and the screw mounting portion 1b is easily deformed at this step, so that the frame of the base 1 is formed. Distortion hardly occurs at the portion where the joints 2 are joined, and the transmission of stress to the frame 2 can be effectively suppressed. Further, since the screw attachment portion 1b and the portion where the frame 2 of the base 1 is joined are integrally formed, there is no weak joint portion and the package is not damaged.
[0026]
h2 is preferably 1.5 × h1 ≦ h2 ≦ 3 × h1. When h2 <1.5 × h1, the thickness difference between h1 and h2 is too small, so that the screw mounting portion 1b is extremely deformed when the package is screwed and fixed to an external electric circuit board having particularly poor flatness. When the size is increased, even the portion of the base 1 to which the frame 2 is joined is easily deformed, and the frame 2 is easily deformed. If h2> 3 × h1, the portion of the base 1 to which the frame 2 is joined becomes too thick, and the position of the optical semiconductor element 10 must be increased to be the same as the optical fiber 6, and the package Becomes larger.
[0027]
As shown in FIG. 1, the shape of the screw mounting portion 1b in plan view may be such that two opposing deformed portions of the base 1 where the screw mounting portion 1b exists are each extended outside the frame body 2. As shown in FIG. 3, the four corners of the base 1 may be extended so as to protrude outside the frame body 2, and one through hole 1 c may be formed in each extension.
[0028]
The outer surface of the frame 2 is located inside the step D (FIG. 2) between the base 1 and the screw mounting portion 1b, and the distance d between the outer surface of the frame 2 and the step D is 0 mm ≦ d. It is preferred that ≦ 3 mm. Thereby, even if a screw is inserted into the screw mounting portion 1b and the base 1 is fixed to the external electric circuit board by screwing, the screw mounting portion 1b is deformed outside the frame 2 so that the frame 2 is distorted. It can be effectively prevented from joining. When d> 3 mm, the size of the base 1 becomes unnecessarily large, which is not suitable for recent miniaturization tendency. On the other hand, when the outer surface of the frame 2 is outside the stepped portion D, the screw attachment 1b comes into contact with the frame 2 due to deformation of the screw attachment 1b, and the frame 2 is easily distorted. Further, the bonding area between the frame 2 and the base 1 is reduced, and the bonding strength between the frame 2 and the base 1 is likely to be reduced.
[0029]
The mounting substrate 1-A of the present invention has a thickness smaller than a portion of the base 1 to which the frame 2 is joined, and the longitudinal elastic coefficient of the mounting substrate 1-A is smaller than that of the base 1. It is getting bigger. Accordingly, when a screw is inserted into the screw mounting portion 1b and the package is screwed to the external electric circuit board, even if stress is generated in the screw mounting portion 1b due to the tightening of the screw, the longitudinal elastic modulus is reduced. By deforming the screw mounting portion 1b of the base 1 smaller than -A, the stress can be relieved without causing distortion in the mounting substrate 1-A, and the light mounted on the mounting substrate 1-A can be reduced. The position accuracy of the semiconductor element 10 can be maintained satisfactorily.
[0030]
Further, even if a large amount of heat is generated by the operation of the optical semiconductor element 10 and the mounting substrate 1-A thermally expands due to the heat, the base 1 having a smaller longitudinal elastic coefficient than the mounting substrate 1-A is generated. Stress that is caused by thermal expansion of the mounting substrate 1-A can be absorbed, and transmission of stress to the joint between the frame 2 and the base 1 is suppressed, thereby effectively suppressing distortion of the package. Can be.
[0031]
Further, since the mounting substrate 1-A is thinner than the portion where the frame 2 of the base 1 is bonded, the bonding area between the base 1 and the mounting substrate 1-A is reduced, and the mounting substrate 1-A is reduced. Even if 1-A thermally expands, the strain applied to the base 1 is reduced and the deformation of the base 1 is reduced. That is, transmission of stress from the mounting substrate 1-A to the frame 2 can be effectively suppressed. Further, the heat of the optical semiconductor element 10 can be efficiently transferred to the external electric circuit board and the heat radiating plate below the mounting substrate 1-A, and the heat radiation property is improved.
[0032]
Such a mounting substrate 1-A is made of a material having a larger modulus of longitudinal elasticity than the base 1, such as a sintered material of Fe-Ni-Co alloy or Cu-W, and is made of metal such as injection molding or cutting. It is manufactured in a predetermined shape by applying a processing method. The mounting substrate 1-A is fitted into the through hole 1d of the base 1 by brazing with an Ag braze or the like.
[0033]
An optical semiconductor element 10 such as an LD or PD is mounted and fixed on the mounting portion 1a on the upper surface of the mounting substrate 1-A. The mounting substrate 1-A also serves as a heat radiating plate for radiating heat generated when the optical semiconductor element 10 operates to the outside. The optical semiconductor element 10 is mounted on a base 11 such as a Peltier element or a circuit board in order to efficiently radiate heat generated during operation to the outside via the mounting substrate 1-A. It may be mounted and fixed on the mounting portion 1a.
[0034]
The thickness h3 of the mounting substrate 1-A is such that h3 <h2 with respect to the thickness h2 of the portion of the base 1 to which the frame 2 is joined. Accordingly, the bonding area between the base 1 and the mounting substrate 1-A is reduced, and even when the mounting substrate 1-A thermally expands, the strain applied to the base 1 is reduced, and the deformation of the base 1 is reduced. . That is, transmission of stress from the mounting substrate 1-A to the frame 2 can be effectively suppressed. Further, the heat of the optical semiconductor element 10 can be efficiently transferred to the external electric circuit board and the heat radiating plate below the mounting substrate 1-A, and the heat radiation property is improved. Further, since the mounting substrate 1-A can be made thinner, the volume of the container formed by the mounting substrate 1-A, the base 1, and the frame 2 can be sufficiently secured, and the package can be reduced in size. Is possible.
[0035]
h3 is preferably 0.3 × h2 ≦ h3 ≦ 0.9 × h2. When h3 <0.3 × h2, the mounting substrate 1-A is thinned, the strength is reduced, and the mounting substrate 1-A is easily distorted. If h3> 0.9 × h2, the bonding area between the mounting substrate 1-A and the base 1 increases, and the mounting substrate 1-A is moved by heat generated by the operation of the optical semiconductor element 10. When thermally expanded, the base 1 is easily deformed greatly, and the stress is easily transmitted to the frame 2.
[0036]
H3 is preferably h1 <h3 ≦ 0.9 × h2. Thereby, the mounting substrate 1-A can be made hard to deform, and even when the base 1 is largely deformed, the positional accuracy between the optical semiconductor element 10 and the optical fiber 6 mounted on the mounting portion 1a is improved. , And the decrease in the optical coupling efficiency can be effectively suppressed.
[0037]
Furthermore, it is preferable that the mounting substrate 1-A be thicker at the outer periphery than the mounting portion 1a. This makes it possible to increase the strength of the mounting substrate 1-A so that it is difficult to deform, and since the mounting portion 1a is thin, heat generated in the optical semiconductor element 10 can be efficiently transferred to the external electric circuit board. Or a heat sink.
[0038]
In addition, on the surfaces of the base 1 and the mounting substrate 1-A, a Ni layer having a thickness of 0.5 to 9 μm or It is preferable that a metal layer made of a gold (Au) layer having a thickness of 0.5 to 5 μm is applied by a plating method or the like.
[0039]
The frame 2 is joined to the outer peripheral portion of the upper main surface of the base 1 so as to surround the through hole 1d inside the screw mounting portion 1b, and the through hole 2a is formed in the side portion. It is a substantially rectangular frame.
[0040]
The frame 2, together with the base 1 and the mounting substrate 1-A, forms a space for accommodating the optical semiconductor element 10 inside the frame 2, and is fitted into the through hole 2a on the side thereof or the through hole 2a. The optical fiber 6 is supported and fixed via a cylindrical fixing member 3 having one end joined to the periphery of the opening outside the frame 2.
[0041]
Such a frame 2 is made of an Fe—Ni—Co alloy, a Cu—W sintered material or the like similarly to the mounting substrate 1 -A, and is brazed to the base 1 via a brazing material such as Ag brazing. The base 1 is erected on the outer peripheral portion of the upper main surface of the base 1 by being welded or joined by a welding method such as a seam welding method.
[0042]
The fixing member 3 is a cylindrical member such as a cylindrical member for fixing the optical fiber 6 to a side portion of the frame 2, and is made of a metal such as an Fe-Ni-Co alloy or stainless steel. The fixing member 3 is provided with a through hole 3a for inserting the optical fiber 6 in the axial direction, and the outer peripheral surface is fitted to the inner surface of the through hole 2a on the side of the frame 2 via a brazing material. Alternatively, one end of the through hole 2a is joined to the periphery of the opening on the outside of the frame body 2 via a brazing material, thereby being fixed to the side of the frame body 2.
[0043]
The screw mounting portion 1b is preferably provided on the side of the frame 2 where the through hole 2a to which the optical fiber 6 is fixed is formed, and on the side of the frame 2 opposed to this side. Thus, it is possible to suppress the stress generated when the package is screwed and fixed to the external electric circuit board from being applied to the side of the frame 2 to which the optical fiber 6 is fixed. That is, the bending stress of the base 1 is most likely to be largest in a portion located between the two screw mounting portions 1b extending in opposite directions, whereas the two screws on the same side of the frame 3 are The bending stress of the base 1 is small in the portion located between the mounting portions 1b, and the position of the optical fiber 6 is fixed by fixing the optical fiber 6 on the side of the frame 2 corresponding to the portion having a small bending stress. Deviation can be effectively suppressed.
[0044]
Further, the shape of the through-hole 1c in a plan view does not need to be circular as shown in FIG. 1, but may be square or semicircular.
[0045]
The optical semiconductor device of the present invention is mounted on the mounting substrate 1 -A so as to be optically coupled to the package having the above configuration, the optical fiber 6 inserted and fixed in the fixing member 3, and the optical fiber 6. And a lid 5 bonded to the upper surface of the frame 2.
[0046]
Such an optical semiconductor device is manufactured as follows. First, after the optical semiconductor element 10 is mounted and fixed on the mounting part 1a via the base 11 such as a Peltier element or a circuit board in the package having the above configuration, the electrodes of the optical semiconductor element 10 and the side parts of the frame 2 are fixed. Alternatively, an electrode inside the frame 2 of an input / output terminal (not shown) functioning as a conductive path inside and outside the package provided on the base 1 is electrically connected to the upper surface of the frame 2 by a bonding wire. The optical semiconductor element 10 is hermetically sealed by joining the lid 5 made of a metal such as an Fe-Ni-Co alloy, ceramics, resin or the like by a welding method such as a brazing method or a seam welding method. Then, a frame-shaped or cylindrical metal holder 7 into which the optical fiber 6 is inserted and fixed is set so that the optical input / output end face of the optical semiconductor element 10 and the optical input / output end face of the optical fiber 6 face and optically couple. The optical semiconductor device is manufactured by welding the fixing member 3 to one end of the fixing member 3 outside the frame 2.
[0047]
The optical semiconductor device of the present invention is screwed and fixed to an external electric circuit board by a screw mounting portion 1b, and one end of a lead terminal or a ribbon wire is brazed to an electrode outside the frame 2 of the input / output terminal to form a lead terminal or a ribbon. By connecting the other end of the wire to an external electric circuit, the optical semiconductor element 10 housed inside the optical semiconductor device is electrically connected to the external electric circuit, and the optical semiconductor element 10 operates with a high-frequency signal.
[0048]
In such an optical semiconductor device, the optical semiconductor element 10 is optically excited by a drive signal supplied from an external electric circuit, and an optical signal such as an excited laser beam is input to the optical fiber 6 and transmitted through the optical fiber 6. Or by converting an optical signal into an electrical signal by causing the optical semiconductor element 10 to receive an optical signal transmitted from the outside through the optical fiber 6 and thereby transmitting a large amount of information at a high speed. It functions and is often used in the optical communication field and the like.
[0049]
Note that the present invention is not limited to the above-described embodiment, and various changes can be made without departing from the spirit of the present invention. For example, one end of the fixing member 3 may be brazed or welded around the outer opening of the frame 2 of the through hole 2a, so that it is not necessary to fit the outer peripheral surface of the fixing member 3 to the inner surface of the through hole 2a. Therefore, the accuracy of the inner diameter of the through hole 2a and the outer dimension of the fixing member 3 can be made relatively coarse, and the processing of the through hole 2a and the fixing member 3 becomes easy, thereby improving the working efficiency.
[0050]
【Example】
An embodiment of the package for housing an optical semiconductor element of the present invention will be described below.
[0051]
A sample of the package of the present invention shown in FIG. 1 was produced as follows. It is a rectangular parallelepiped formed of an Fe-Ni-Co alloy (longitudinal modulus of elasticity: 128 GPa) with a length of 21 mm x a width of 13 mm and a thickness of 1.8 mm. A substrate 1 was prepared, and screw attachment portions 1b (see Table 1) having various thicknesses were formed at the four corners.
[0052]
Then, a frame 2 made of an Fe-Ni-Co alloy and having a length of 21 mm x a width of 13 mm x a height of 7 mm and a thickness of 1 mm was prepared.
[0053]
Further, a mounting substrate 1-A having a length of 9.5 mm, a width of 7.5 mm, and a height of 1.5 mm made of a sintered body of Cu-W (longitudinal modulus of elasticity: 265 GPa) is fitted into the through-hole 1d, and , The frame 2 and the mounting substrate 1-A were joined with an Ag-Cu brazing material (melting point: 780 ° C.), and these were uniformly cooled to room temperature (25 ° C.) to produce a package (samples P1 to P7). .
[0054]
When these samples P1 to P7 were screwed to an external circuit board having a flat upper surface, displacements generated by strain in the thickness direction at the center of the mounting substrate were obtained by analysis by the finite element method. Table 1 shows the evaluation results.
[0055]
[Table 1]
[0056]
From the results shown in Table 1, the displacement generated at the center of the mounting substrate in the sample of the present invention was reduced to 40 μm by making the thickness of the screw attachment portion thinner than the portion of the base 1 to which the frame was joined. The values can be reduced to the following values, and it has been found that the package of the present invention is effective in suppressing the optical axis shift between the optical fiber 6 and the optical semiconductor element 10.
[0057]
In particular, by setting the thickness of the screw mounting portion 1b to ２ or less of the thickness of the base 1, the displacement can be reduced to 20 μm or less, and the displacement of the optical axis between the optical fiber 6 and the optical semiconductor element 10 can be prevented. It turned out to be very effective.
[0058]
It should be noted that the present invention is not limited to the above-described examples and examples, and various changes may be made without departing from the scope of the present invention.
[0059]
【The invention's effect】
The optical semiconductor element housing package of the present invention has a substantially rectangular parallelepiped metal base having a through hole at the center and screw mounting portions formed at four corners, respectively, and an optical module on the upper surface fitted into the through hole. A mounting substrate on which a semiconductor element is mounted and fixed, and a metal formed on the outer peripheral portion of the upper main surface of the base so as to surround the through hole inside the screw mounting portion and form a through hole on the side portion. And a cylindrical optical fiber fixing member that is fitted into the through hole or that has one end joined to the periphery of the opening of the through hole outside the frame. The thickness of the mounting substrate is thinner than the portion where the frame of the base is joined, and the longitudinal elastic coefficient of the mounting substrate is larger than that of the base. Screw the external package to the external electric circuit board. Even if stress is generated in the mounting portion, the stress can be relieved without deforming the mounting substrate by deforming the screw mounting portion of the base having a smaller longitudinal elastic modulus than the mounting substrate, The positional accuracy of the optical semiconductor element mounted on the mounting substrate can be maintained satisfactorily.
[0060]
In addition, even if a large amount of heat is generated by the operation of the optical semiconductor element, and the mounting substrate thermally expands due to the heat, the base having a smaller longitudinal elastic modulus than the mounting substrate is caused by the thermal expansion of the mounting substrate. The stress can be absorbed, and the transmission of the stress to the joint between the frame and the base can be suppressed, so that the optical semiconductor element housing package can be effectively prevented from being distorted.
[0061]
Furthermore, since the mounting substrate is thinner than the portion where the frame of the base is bonded, the bonding area between the base and the mounting substrate is reduced, so that the mounting substrate is added to the base even when thermally expanded. The distortion is reduced and the deformation of the base is reduced. That is, transmission of stress from the mounting substrate to the frame body can be effectively suppressed. Further, the heat of the optical semiconductor element can be efficiently transmitted to the external electric circuit board and the heat radiating plate below the mounting substrate, so that the heat radiating property is improved.
[0062]
Also, a step is formed due to a thickness difference between the screw attachment portion and the portion where the frame of the base is joined, and the screw attachment portion is easily deformed at this step, so that the portion where the frame of the base is joined is formed. In this case, distortion is less likely to occur, and transmission of stress to the frame can be effectively suppressed. Further, since the screw attachment portion and the portion where the frame of the base is joined are formed integrally, there is no weak joint portion, and the package for housing the optical semiconductor element is not damaged.
[0063]
As a result, when the optical semiconductor element housing package is screwed and fixed to the external electric circuit board or when heat is generated by the operation of the housed optical semiconductor element, stress is relieved to reduce the stress of the optical semiconductor element housing package. It is necessary to effectively suppress distortion and breakage, maintain normal transmission and reception of optical signals between the optical input / output end face of the optical semiconductor element and the optical input / output end face of the optical fiber, and achieve excellent optical coupling efficiency. it can.
[0064]
The optical semiconductor device of the present invention includes an optical semiconductor element housing package of the present invention, an optical fiber inserted and fixed in an optical fiber fixing member, and a mounting substrate so as to be optically coupled to the optical fiber. By providing the mounted optical semiconductor element and the lid joined to the upper surface of the frame, the reliability using the optical semiconductor element housing package of the present invention is improved.
[Brief description of the drawings]
FIG. 1 is a plan view showing an example of an embodiment of an optical semiconductor element housing package of the present invention.
FIG. 2 is a cross-sectional view taken along line AA ′ of the optical semiconductor element housing package of FIG.
FIG. 3 is a plan view showing another example of the embodiment of the package for housing an optical semiconductor element of the present invention.
FIG. 4 is a plan view of a conventional package for housing an optical semiconductor element.
5 is a cross-sectional view of the package for storing an optical semiconductor element of FIG. 4 taken along line BB ′.
[Explanation of symbols]
1: Substrate
1a: Receiver
1b: Screw mounting part
1c: Through hole
1d: Through hole
1-A: mounting substrate
2: Frame
2a: Through hole
3: Optical fiber fixing member
5: Lid
6: Optical fiber
10: Optical semiconductor device