JP3652255B2

JP3652255B2 - Package for storing semiconductor elements

Info

Publication number: JP3652255B2
Application number: JP2001019158A
Authority: JP
Inventors: 宗裕上村; 清孝横井
Original assignee: Kyocera Corp
Current assignee: Kyocera Corp
Priority date: 2001-01-26
Filing date: 2001-01-26
Publication date: 2005-05-25
Anticipated expiration: 2021-01-26
Also published as: JP2002222882A

Description

【０００１】
【発明の属する技術分野】
本発明は、半導体素子を収容し外部電気回路基板にネジ取付部を介してネジ止めされる半導体素子収納用パッケージに関する。
【０００２】
【従来の技術】
従来の、外部電気回路基板（図示せず）にネジ取付部を介してネジ止めされる半導体素子収納用パッケージ（以下、半導体パッケージという）の例を図３，図４に斜視図で示す。
【０００３】
図３に示すように、半導体パッケージは、一般に略四角形の基体１１と基体１１の上面に取着された枠体１４とを具備して成る。基体１１は、その上面に半導体素子１７が載置される載置部１１ａと、対向する辺部にそれぞれ形成されたネジ取付部１１ｂとを有し、鉄（Ｆｅ）−ニッケル（Ｎｉ）−コバルト（Ｃｏ）合金や銅（Ｃｕ）−タングステン（Ｗ）合金等の金属材料から成る。枠体１４は、１対の対向する側壁の内面と外面の一部を切り欠いて形成された取付部１２ａ、および取付部１２ａの内外を導通するように形成されたメタライズ層１２ｂから成り、内外を電気的に導通し接続する入出力部１２を有し、他の１対の対向する側壁の外面にはメタライズ金属層１３が形成されている。そして、枠体１４は、基体１１して取着され、アルミナ（Ａｌ₂Ｏ₃）セラミックスや窒化アルミニウム（ＡｌＮ）セラミックス等のセラミックス等の絶縁材料から成る。
【０００４】
この枠体１４のメタライズ金属層１３は、基体１１の上面に枠体１４の下面を銀ロウ等のロウ材で接合した際に、枠体１４の下面からメタライズ金属層１３にかけてロウ材のメニスカスを形成することにより接合を強固なものとするものであり、また外部からの電磁波をシールドする所謂電磁シールド層として機能する。
【０００５】
なお、この半導体パッケージは、図４に示すように、枠体１４の１対の対向する側壁の一部を内外を貫通するように切り欠くか、または貫通孔を形成して成る入出力部１２の取付部１２ａを有するとともに、枠体１４の内外を導通するメタライズ層１２ｂが形成された、セラミックス等の絶縁体から成る入出力部１２を取付部１２ａに嵌着接合した構成のものもある。この場合、枠体１４はＦｅ−Ｎｉ−Ｃｏ合金やＦｅ−Ｎｉ合金等の金属材料から成り、基体１１の上面に載置部１１ａを囲繞するように取着される。
【０００６】
また、メタライズ層１２ｂは、取付部１２ａや入出力部１２に枠体１４の内外を導通するように設けられており、メタライズ層１２ｂの枠体１４外側の部位の表面に外部電気回路基板と電気的に接続される、Ｆｅ−Ｎｉ−Ｃｏ合金やＦｅ−Ｎｉ合金等の金属材料から成るリード端子１６が銀ロウ等のロウ材で接合される。
【０００７】
このような半導体パッケージにおいて、基体１１上面の載置部１１ａに半導体素子１７を樹脂接着剤，ロウ材等の接着剤を介して接着固定するとともに、半導体素子１７の電極をボンディングワイヤ（図示せず）を介して、半導体パッケージ内部のメタライズ層１２ｂに接続し、しかる後、枠体１４上面に蓋体（図示せず）を金（Ａｕ）−錫（Ｓｎ）等の低融点ロウ材で接合することにより、製品としての半導体装置となる。
【０００８】
このような半導体装置は、外部電気回路基板にネジ取付部１１ｂを介してネジ止め固定され、外部電気回路基板から供給される駆動信号により半導体素子１７を作動させ、大容量の情報を高速に伝送できる装置として機能する。
【０００９】
【発明が解決しようとする課題】
しかしながら、上記従来の半導体パッケージにおいて、その小型化のためにネジ取付部１１ｂと枠体１４の外周面とは近接しており、基体１１とメタライズ金属層１３との間、または基体１１と枠体１４の下面との間に形成されるフィレット（メニスカス）が大きくなる場合、フィレットがネジ取付部１１ｂ周辺部にまで広がって延在した不要なロウ材溜まりと成る。すると、ネジがロウ材溜まりを介してネジ取付部１１ｂに取り付けられることと成るため、基体１１上面のネジ取付部１１ｂ周辺部をネジで強固に固定できない。即ち、半導体パッケージを外部電気回路基板にネジで強固に固定できないため、基体１１下面が外部電気回路基板に完全に密着せず、半導体素子１７の作動時に発する熱を効率良く外部電気回路基板に伝熱することができない。そのため、半導体素子１７は作動性が損なわれたり、熱により破損したりする等の問題点があった。
【００１０】
なお、上記問題点を解決する手段として、図３，図４においてネジ取付部１１ｂと枠体１４外周面との間隔を大きくすることも考えられるが、この場合、半導体パッケージが大型化することとなり、近時の小型化，軽量化の動向から外れることとなる。
【００１１】
従って、本発明は上記問題点に鑑み完成されたもので、その目的は、ネジ取付部の周辺部でロウ材溜まりが発生するのを有効に防止することにより、半導体パッケージを外部電気回路基板に強固にネジで固定できるようにし、また半導体素子の発する熱を効率良く外部電気回路基板に伝え、半導体素子を長期にわたり正常かつ安定に作動させることにある。
【００１２】
【課題を解決するための手段】
本発明の半導体素子収納用パッケージは、枠体の外周面のネジ取付部に近接した部位に、ネジ取付部の基体上面の中心部側の先端に対応するように、枠体の外周面の下側から枠体の下面にかけて基体と枠体の接合部からネジ取付部に向かうロウ材の広がりを防ぐ切欠部が形成されていることを特徴とするものである。
【００１３】
本発明は、上記の構成により、ネジ取付部の周辺部にロウ材溜まりの発生を有効に防止でき、半導体パッケージの下面を外部電気回路基板の上面に完全に密着できる。そのため、半導体素子の発する熱を効率良く外部電気回路基板に伝えることができ、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。
【００１４】
【発明の実施の形態】
本発明の半導体パッケージについて以下に詳細に説明する。図１，図２は本発明の半導体パッケージを示し、図１は、枠体が絶縁材料である場合の実施の形態の一例を示す斜視図、図２は、枠体とネジ取付部との周辺部の要部拡大斜視図である。
【００１５】
これらの図において、１は基体、４は枠体、７は半導体素子である。これら基体１，枠体４とで半導体素子７を収容するための容器が構成される。
【００１６】
基体１は略四角形の金属板から成り、Ｆｅ−Ｎｉ−Ｃｏ合金やＣｕ−Ｗ合金等の金属材料から成り、上面の略中央部に半導体素子７を載置固定するための載置部１ａを有するとともに、基体１の対向する辺部に貫通孔または上下面を貫通する切欠部から成るネジ取付部１ｂがそれぞれ設けられ、ネジ取付部１ｂにネジを通して外部電気回路基板にネジ止めされる。
【００１７】
この基体１は半導体素子７の作動時に発する熱を効率良く外部電気回路基板に伝熱する、所謂放熱板として機能するとともに、半導体素子７を支持する支持部材として、さらには外部電気回路基板に固定される固定基板として機能する。
【００１８】
そして、基体１は、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、所定の形状に製作される。また、基体１の表面には、耐蝕性に優れかつロウ材との濡れ性に優れる金属、具体的には厚さ０．５〜９μｍのＮｉ層と、厚さ０．５〜５μｍのＡｕ層とを順次メッキ法により被着させておくと、基体１が酸化腐食するのを有効に防止できるとともに、基体１上面に半導体素子７を強固に接着固定できる。従って、基体１の表面には、０．５〜９μｍのＮｉ層や０．５〜５μｍのＡｕ層等の金属層をメッキ法により被着させておくことが好ましい。
【００１９】
また、基体１は、その上面に半導体素子７が載置される載置部１ａを囲繞するように、枠体４が銀ロウ等のロウ材で接合されており、枠体４の内側に半導体素子７を収容するための空所が形成される。枠体４の１対の対向する側部に内外を電気的に導通する入出力部２が設けられる。
【００２０】
枠体４は平面視形状が略四角形の枠状であり、枠体４がセラミックス等の絶縁材料から成る場合、1対の対向する側部の内面および外面の一部を切り欠いて形成された取付部２ａ、および取付部２ａの内外面を導通するように形成されたメタライズ層２ｂから成る入出力部２を有する。また、枠体４の他の１対の対向する側部の外面にはメタライズ金属層３が形成され、枠体４の外周面のネジ取付部１ｂに最も近接した部位に枠体４の外周面の下側から枠体４の下面にかけて切欠部５が形成されている。また、ネジ取付部１ｂは枠体４の外周面よりも外側に突出している。ネジ取付部１ｂと枠体４の外周面との間隔は、半導体パッケージの小型化のために数ｍｍ程度以下と小さなものである。
【００２１】
一方、枠体４がＦｅ−Ｎｉ−Ｃｏ合金やＦｅ−Ｎｉ合金等の金属材料から成る場合、１対の対向する側部の内外を貫通するように切り欠くか、または貫通孔を形成することにより設けられた入出力部の取付部を有する。この取付部に内外を導通するメタライズ層が形成された、セラミックス等の絶縁材料から成る入出力部を嵌着接合する。
【００２２】
枠体４が絶縁材料から成る場合、Ａｌ₂Ｏ₃セラミックスやＡｌＮセラミックス等から成り、以下のようにして作製される。まず、セラミックスの原料粉末に適当な有機バインダや溶剤等を添加混合しペースト状と成す。このペーストをドクターブレード法やカレンダーロール法によってセラミックグリーンシートと成す。しかる後、セラミックグリーンシートに適当な打ち抜き加工を施し、これを複数枚積層し、約１６００℃の高温で焼成することによって作製される。
【００２３】
また、メタライズ層２ｂは、半導体素子７と外部電気回路基板との電気的接続を行うものであり、その表面に、ボンディングワイヤやリード端子６との接合を容易かつ強固なものとするために、０．５〜９μｍのＮｉ層と０．５〜５μｍのＡｕ層が順次メッキ法により被着されている。そのため、半導体素子７はボンディングワイヤを介して、さらに外部電気回路基板にリード端子６を介して接続され、駆動信号の伝達が良好なものとなる。
【００２４】
また、メタライズ金属層３は、基体１の上面に枠体４を銀ロウ等のロウ材で接合した際に、それらの接合部位、即ち枠体４の下面と枠体４の外周面のメタライズ金属層３にロウ材のメニスカスを形成することにより、接合を強固なものとするものである。また、半導体パッケージの外部からの電磁波をシールドする所謂電磁シールド層として機能する。
【００２５】
これらメタライズ層２ｂ，メタライズ金属層３は、タングステン（Ｗ）やモリブデン（Ｍｏ）、マンガン（Ｍｎ）等で形成されており、例えば、Ｗ等の粉末に有機溶剤、溶媒を添加混合して得た金属ペーストを、枠体４用のセラミックグリーンシートに、予め従来周知のスクリーン印刷法により所定パターンに印刷塗布しておくことによって枠体４に形成される。
【００２６】
また、本発明の切欠部５は、メタライズ金属層３と基体１上面により形成されるフィレットが、ロウ材過多等により非常に大きくなり不要なロウ材溜まりと成るのを有効に防止でき、その結果半導体パッケージの下面を外部電気回路基板の上面に完全に密着させ得る。そのため、半導体素子７の発する熱を効率良く外部電気回路基板に伝えることができ、半導体素子７を長期にわたり正常かつ安定に作動させ得る。
【００２７】
この切欠部５は、枠体４の外周面のネジ取付部１ｂに最も近接した部位に、枠体４の外周面の下側から枠体４の下面にかけて形成される。また、切欠部５は、その中心がネジ取付部１ｂの基体１上面の中心部側の先端に対応するように形成されているのが好ましく、また１つの切欠部５の幅は、ネジ取付部１ｂの最大幅の１／５〜（ネジ頭（略円板状の頭部）の直径の２．５倍）であることが好ましい。
【００２８】
１つの切欠部５の幅が、ネジ取付部１ｂの最大幅の１／５未満の場合、ロウ材過多の際にロウ材溜まりが発生し易くなる。一方、この幅がネジ頭の直径の２．５倍を超える場合、基体１と枠体４との接合を強固なものとするフィレットが小さくなり、それらの接合強度が低下し易くなる。
【００２９】
また、切欠部５の基体１上面からの高さは０．１５ｍｍ以上であることが好ましく、０．１５ｍｍ未満の場合、切欠部５の上方のメタライズ金属層３と基体１上面とでロウ材によるブリッジが発生し易くなり、このブリッジがロウ材溜まりとなり、ネジ止めした際の問題点を誘発させることとなる。
【００３０】
また、切欠部５の枠体４厚さ方向の長さ、所謂奥行きは、０．１〜１．５ｍｍが好ましく、０．１ｍｍ未満の場合、ロウ材過多の際にロウ材溜まりが発生し易くなる。一方、１．５ｍｍを超える場合、基体１と枠体４との接合面積が小さくなることにより接合が損なわれ、半導体素子７を半導体パッケージ内部に気密に収容できない傾向にある。従って、切欠部５の枠体４厚さ方向の長さは、０．１〜１．５ｍｍが好ましい。
【００３１】
また、切欠部５の断面形状は、多角形，円形，楕円形等種々の形状であっても良く、多角形の場合は角部にＲ（円弧状の凹形曲面）があっても良い。
【００３２】
なお、この切欠部５は、ネジ取付部１ｂの周辺部にロウ材溜まりの発生を有効に防止することにより、結果として半導体パッケージの下面を外部電気回路基板の上面に完全に密着させ、伝熱効果を向上させる機能を有する。そのうえ、基体１と枠体４との接合後における熱膨張係数差による残留熱応力により、枠体４に比較して弾性率の低い基体１が反り変形を起こし、基体１下面を外部電気回路基板に完全に密着させて固定するのが困難になるのを有効に防止する機能も有する。
【００３３】
即ち、切欠部５は基体１と枠体４との接合時における熱応力を緩和する機能も有しており、それらの接合後における基体１の反り変形を有効に防止するという優れた効果も奏する。
【００３４】
また、半導体パッケージを外部電気回路基板に完全に密着して固定させるために、ネジをトルクをかけて強固に固定した場合、基体１の下面、特に載置部１ａ直下が大きく反り変形を起こし易い。その結果、半導体素子７と載置部１ａとの固定が損なわれたり、枠体４にクラック等の破損が発生する等の問題が発生し、半導体素子７の気密性や作動性が損なわれることとなる。このような問題を解決する手段としても、切欠部５は有効に機能する。
【００３５】
このように、切欠部５を設けることにより、ロウ材溜まりの発生を防止し、半導体パッケージと外部電気回路基板との密着を完全なものとし、また半導体パッケージが大型化するのを回避できる。さらに、基体１と枠体４との接合後における残留熱応力の発生を防止し、半導体パッケージの外部電気回路基板への固定を良好なものとできる。
【００３６】
本発明において、枠体４の上面には、蓋体（図示せず）がＡｕ−Ｓｎ等の低融点ロウ材で接合され、半導体素子７の酸化等による作動性の劣化を有効に防止し、半導体素子７を気密に封止する。
【００３７】
本発明の半導体パッケージは、金属材料から成りネジ取付部１ｂを有する基体１の上面に、半導体素子７の載置部１ａを囲繞するように、１対の対向する側部の内外を電気的に導通する入出力部２を有する枠体４をロウ材で取着して成り、ネジ取付部１ｂは枠体４の外周面よりも外側に突出しており、枠体４の外周面のネジ取付部１ｂに最も近接した部位に枠体４の外周面の下側から枠体４の下面にかけて切欠部５が形成されていることを特徴としている。
【００３８】
このような半導体パッケージに、半導体素子７を樹脂接着剤，ロウ材等の接着剤を介して接着固定するとともに、半導体素子７の電極をボンディングワイヤを介して、半導体パッケージ内部のメタライズ層２ｂに接続し、しかる後、枠体４の上面に蓋体をＡｕ−Ｓｎ等の低融点ロウ材で接合することにより、製品としての半導体装置となる。
【００３９】
かくして、本発明は、ネジ取付部１ｂ周辺部にロウ材溜まりが発生するのを有効に防止できるため、外部電気回路基板と半導体パッケージとの密着固定を良好なものとし、半導体素子７を長期にわたり正常かつ安定に作動させ得る。
【００４０】
なお、本発明は、上記実施の形態に限定されず、本発明の要旨を逸脱しない範囲内において種々の変更を行うことは何等支障無い。
【００４１】
例えば、切欠部５が上記実施の形態の形状であれば、その内面にメタライズ金属層３を形成してもよく、その場合でもロウ材溜まりは有効に防止できる。また、この場合、上記実施の形態の場合に比し、外部からの電磁波をよりシールドできる。さらに、切欠部５は枠体４の外周面に枠体４の上下面を貫通するように形成されてもよい。その場合、切欠部５の内面にメタライズ金属層３を形成すれば、ロウ材は面積の大きな切欠部５の内面で濡れるため、ロウ材は切欠部５で枠体４の外側に漏れにくくなり、枠体４の外側におけるロウ材溜まりの形成がさらに有効に防止できる。
【００４２】
また、半導体素子７は、ＬＤ（半導体レーザ），ＰＤ（フォトダイオード）等の光信号により作動する光半導体素子であっても良く、この場合、光半導体素子を収納する容器は、光ファイバや光アイソレータ等の光学部品を実装するための光半導体パッケージとなる。
【００４３】
【発明の効果】
本発明は、基体のネジ取付部は枠体の外周面よりも外側に突出しており、枠体の外周面のネジ取付部に最も近接した部位に、枠体の外周面の下側から枠体の下面にかけて基体と枠体の接合部からネジ取付部に向かうロウ材の広がりを防ぐ切欠部が形成されていることにより、ネジ取付部周辺のロウ材溜まりの発生を防止し、その結果半導体パッケージと外部電気回路基板との密着を完全なものとできる。また、半導体パッケージが大型化するのを回避できるとともに、基体と枠体との接合後における残留熱応力の発生を防止し、半導体パッケージの外部電気回路基板への固定を良好なものとできる。
【図面の簡単な説明】
【図１】本発明の半導体パッケージについて実施の形態の一例を示す斜視図である。
【図２】図１の枠体とネジ取付部の周辺部の要部拡大斜視図である。
【図３】従来の半導体パッケージの斜視図である。
【図４】従来の半導体パッケージの斜視図である。
【符号の説明】
１：基体
１ａ：載置部
１ｂ：ネジ取付部
２：入出力部
４：枠体
５：切欠部
７：半導体素子[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a package for housing a semiconductor element that houses a semiconductor element and is screwed to an external electric circuit board via a screw mounting portion.
[0002]
[Prior art]
An example of a conventional package for housing a semiconductor element (hereinafter referred to as a semiconductor package) screwed to an external electric circuit board (not shown) via a screw mounting portion is shown in perspective views in FIGS.
[0003]
As shown in FIG. 3, the semiconductor package generally includes a substantially rectangular base body 11 and a frame body 14 attached to the upper surface of the base body 11. The base body 11 has a mounting portion 11a on which the semiconductor element 17 is mounted and a screw mounting portion 11b formed on each of opposite sides, and iron (Fe) -nickel (Ni) -cobalt. It consists of metal materials, such as (Co) alloy and copper (Cu) -tungsten (W) alloy. The frame body 14 is composed of a pair of opposing side walls and a mounting portion 12a formed by cutting out part of the outer surface, and a metallized layer 12b formed so as to be electrically connected to the inside and outside of the mounting portion 12a. The metallized metal layer 13 is formed on the outer surface of the other pair of opposing side walls. The frame 14 is attached as the base 11 and is made of an insulating material such as ceramics such as alumina (Al ₂ O ₃ ) ceramics or aluminum nitride (AlN) ceramics.
[0004]
The metallized metal layer 13 of the frame body 14 has a brazing material meniscus from the lower surface of the frame body 14 to the metallized metal layer 13 when the lower surface of the frame body 14 is joined to the upper surface of the base 11 with a brazing material such as silver brazing. By forming it, the bonding is strengthened, and it functions as a so-called electromagnetic shield layer that shields electromagnetic waves from the outside.
[0005]
In this semiconductor package, as shown in FIG. 4, the input / output unit 12 is formed by cutting out a part of a pair of opposing side walls of the frame body 14 so as to penetrate the inside or outside, or forming a through hole. There is also a configuration in which an input / output part 12 made of an insulator such as ceramics, in which a metallized layer 12b that conducts the inside and outside of the frame body 14 is formed, is fitted and joined to the attachment part 12a. In this case, the frame 14 is made of a metal material such as an Fe—Ni—Co alloy or an Fe—Ni alloy, and is attached to the upper surface of the base 11 so as to surround the mounting portion 11a.
[0006]
Further, the metallized layer 12b is provided so as to conduct the inside and outside of the frame body 14 to the mounting portion 12a and the input / output unit 12, and an external electric circuit board and an electric circuit are formed on the surface of the metallized layer 12b outside the frame body 14. The lead terminals 16 made of a metal material such as Fe—Ni—Co alloy or Fe—Ni alloy are joined together by a brazing material such as silver brazing.
[0007]
In such a semiconductor package, the semiconductor element 17 is bonded and fixed to the mounting portion 11a on the upper surface of the base 11 via an adhesive such as a resin adhesive or a brazing material, and the electrode of the semiconductor element 17 is bonded to a bonding wire (not shown). ), And then a lid (not shown) is joined to the upper surface of the frame 14 with a low melting point brazing material such as gold (Au) -tin (Sn). Thus, a semiconductor device as a product is obtained.
[0008]
Such a semiconductor device is screwed and fixed to an external electric circuit board via a screw mounting portion 11b, and operates a semiconductor element 17 by a drive signal supplied from the external electric circuit board to transmit a large amount of information at high speed. Functions as a device that can.
[0009]
[Problems to be solved by the invention]
However, in the above-described conventional semiconductor package, the screw mounting portion 11b and the outer peripheral surface of the frame body 14 are close to each other for miniaturization, and the base body 11 and the metallized metal layer 13 or between the base body 11 and the frame body. When the fillet (meniscus) formed between the lower surface of 14 becomes large, the fillet becomes an unnecessary brazing material reservoir that extends to the periphery of the screw mounting portion 11b. Then, since the screw is attached to the screw attachment portion 11b via the brazing material reservoir, the periphery of the screw attachment portion 11b on the upper surface of the base 11 cannot be firmly fixed with the screw. That is, since the semiconductor package cannot be firmly fixed to the external electric circuit board with screws, the lower surface of the base 11 is not completely adhered to the external electric circuit board, and the heat generated during the operation of the semiconductor element 17 is efficiently transmitted to the external electric circuit board. I can't heat it. Therefore, the semiconductor element 17 has problems such as loss of operability and damage due to heat.
[0010]
As a means for solving the above problem, it is conceivable to increase the distance between the screw mounting portion 11b and the outer peripheral surface of the frame body 14 in FIGS. 3 and 4, but in this case, the semiconductor package becomes large. This will deviate from the recent trend of miniaturization and weight reduction.
[0011]
Accordingly, the present invention has been completed in view of the above problems, and an object of the present invention is to effectively prevent the occurrence of brazing material accumulation in the peripheral portion of the screw mounting portion, so that the semiconductor package can be mounted on the external electric circuit board. The object is to enable the semiconductor element to operate normally and stably over a long period of time by allowing the semiconductor element to be firmly fixed with screws, and efficiently transferring heat generated by the semiconductor element to the external electric circuit board.
[0012]
[Means for Solving the Problems]
The package for housing a semiconductor element of the present invention is provided below the outer peripheral surface of the frame body so as to correspond to the tip of the screw mounting portion near the screw mounting portion on the outer peripheral surface of the frame body. A notch is formed from the side to the lower surface of the frame to prevent the brazing material from spreading from the joint between the base and the frame toward the screw mounting portion.
[0013]
According to the present invention, the above configuration can effectively prevent the brazing material accumulation in the peripheral portion of the screw mounting portion, and can completely adhere the lower surface of the semiconductor package to the upper surface of the external electric circuit board. Therefore, the heat generated by the semiconductor element can be efficiently transmitted to the external electric circuit board, and the semiconductor element can be operated normally and stably over a long period of time.
[0014]
DETAILED DESCRIPTION OF THE INVENTION
The semiconductor package of the present invention will be described in detail below. 1 and 2 show a semiconductor package of the present invention, FIG. 1 is a perspective view showing an example of an embodiment in which the frame body is made of an insulating material, and FIG. 2 shows the periphery of the frame body and the screw mounting portion. It is a principal part expansion perspective view of a part.
[0015]
In these figures, 1 is a base, 4 is a frame, and 7 is a semiconductor element. The base body 1 and the frame body 4 constitute a container for housing the semiconductor element 7.
[0016]
The base body 1 is made of a substantially rectangular metal plate, made of a metal material such as an Fe—Ni—Co alloy or Cu—W alloy, and a mounting portion 1 a for mounting and fixing the semiconductor element 7 on a substantially central portion of the upper surface. In addition, screw attachment portions 1b each having a through hole or a notch penetrating the upper and lower surfaces are provided in opposing side portions of the base 1, and are screwed to the external electric circuit board through the screw attachment portion 1b.
[0017]
The base body 1 functions as a so-called heat radiating plate that efficiently transfers heat generated during operation of the semiconductor element 7 to the external electric circuit board, and is fixed to the external electric circuit board as a support member for supporting the semiconductor element 7. Functions as a fixed substrate.
[0018]
And the base | substrate 1 is manufactured in a defined shape by giving conventionally well-known metal processing methods, such as rolling and punching, to the ingot. Further, on the surface of the substrate 1, a metal having excellent corrosion resistance and wettability with the brazing material, specifically, a Ni layer having a thickness of 0.5 to 9 μm and an Au layer having a thickness of 0.5 to 5 μm Are successively deposited by a plating method, so that the base 1 can be effectively prevented from being oxidized and corroded, and the semiconductor element 7 can be firmly bonded and fixed to the upper surface of the base 1. Therefore, it is preferable to deposit a metal layer such as a 0.5 to 9 μm Ni layer or a 0.5 to 5 μm Au layer on the surface of the substrate 1 by a plating method.
[0019]
Further, the base body 1 has a frame body 4 joined with a brazing material such as silver solder so as to surround a mounting portion 1 a on which the semiconductor element 7 is mounted on the upper surface thereof, and a semiconductor is formed inside the frame body 4. A space for accommodating the element 7 is formed. An input / output unit 2 that is electrically connected inside and outside is provided on a pair of opposing side portions of the frame body 4.
[0020]
The frame body 4 has a substantially quadrangular frame shape in plan view, and when the frame body 4 is made of an insulating material such as ceramics, the frame body 4 is formed by cutting out a part of the inner surface and the outer surface of a pair of opposing side portions. It has the input / output part 2 which consists of the metallization layer 2b formed so that the attachment part 2a and the inner and outer surfaces of the attachment part 2a may be conducted. Further, a metallized metal layer 3 is formed on the outer surfaces of the other pair of opposing side portions of the frame body 4, and the outer peripheral surface of the frame body 4 is located at a position closest to the screw mounting portion 1 b on the outer peripheral surface of the frame body 4. A notch 5 is formed from the lower side to the lower surface of the frame 4. Further, the screw mounting portion 1 b protrudes outward from the outer peripheral surface of the frame body 4. The distance between the screw mounting portion 1b and the outer peripheral surface of the frame body 4 is as small as about several mm or less in order to reduce the size of the semiconductor package.
[0021]
On the other hand, when the frame 4 is made of a metal material such as an Fe—Ni—Co alloy or an Fe—Ni alloy, the frame body 4 is cut out so as to penetrate the inside or outside of a pair of opposing side portions, or a through hole is formed. The mounting part of the input-output part provided by is provided. An input / output portion made of an insulating material such as ceramics, in which a metallized layer that conducts inside and outside is formed on the mounting portion, is fitted and joined.
[0022]
When the frame 4 is made of an insulating material, it is made of Al ₂ O ₃ ceramics, AlN ceramics or the like, and is manufactured as follows. First, a suitable organic binder, solvent, or the like is added to and mixed with the ceramic raw material powder to form a paste. This paste is formed into a ceramic green sheet by a doctor blade method or a calendar roll method. Thereafter, an appropriate punching process is performed on the ceramic green sheet, and a plurality of these are laminated and fired at a high temperature of about 1600 ° C.
[0023]
Further, the metallized layer 2b is used to electrically connect the semiconductor element 7 and the external electric circuit board, and in order to make the bonding wire and the lead terminal 6 easily and firmly bonded to the surface thereof, A Ni layer of 0.5 to 9 μm and an Au layer of 0.5 to 5 μm are sequentially deposited by a plating method. Therefore, the semiconductor element 7 is connected to the external electric circuit board via the lead terminal 6 via the bonding wire, and the transmission of the drive signal becomes good.
[0024]
Further, the metallized metal layer 3 is formed when the frame 4 is bonded to the upper surface of the base body 1 with a brazing material such as silver brazing, that is, the metallized metal at the bonding portion thereof, that is, the lower surface of the frame 4 and the outer peripheral surface of the frame 4. By forming a braided meniscus on the layer 3, the bonding is strengthened. Also, it functions as a so-called electromagnetic shield layer that shields electromagnetic waves from the outside of the semiconductor package.
[0025]
The metallized layer 2b and the metallized metal layer 3 are made of tungsten (W), molybdenum (Mo), manganese (Mn), or the like. For example, the metallized layer 2b and the metallized metal layer 3 are obtained by adding an organic solvent and a solvent to a powder such as W. The metal paste is formed on the frame 4 by printing and applying in a predetermined pattern to the ceramic green sheet for the frame 4 in advance by a well-known screen printing method.
[0026]
Further, the notch 5 of the present invention can effectively prevent the fillet formed by the metallized metal layer 3 and the upper surface of the base 1 from becoming very large due to excessive brazing material and the like, and becoming an unnecessary brazing material reservoir. The lower surface of the semiconductor package can be completely adhered to the upper surface of the external electric circuit board. Therefore, the heat generated by the semiconductor element 7 can be efficiently transmitted to the external electric circuit board, and the semiconductor element 7 can be operated normally and stably over a long period of time.
[0027]
This notch 5 is formed from the lower side of the outer peripheral surface of the frame body 4 to the lower surface of the frame body 4 at a portion closest to the screw mounting portion 1 b on the outer peripheral surface of the frame body 4. The notch 5 is preferably formed so that the center thereof corresponds to the tip of the upper surface of the base 1 of the screw mounting portion 1b, and the width of one notch 5 is the screw mounting portion. It is preferably 1/5 of the maximum width of 1b (2.5 times the diameter of the screw head (substantially disk-shaped head)).
[0028]
When the width of one notch portion 5 is less than ５ of the maximum width of the screw mounting portion 1b, brazing material pool is likely to occur when the brazing material is excessive. On the other hand, when this width exceeds 2.5 times the diameter of the screw head, the fillet that strengthens the bonding between the base 1 and the frame body 4 becomes small, and the bonding strength thereof tends to decrease.
[0029]
Further, the height of the notch 5 from the upper surface of the base 1 is preferably 0.15 mm or more. When the height is less than 0.15 mm, the metallized metal layer 3 above the notch 5 and the upper surface of the base 1 are made of brazing material. A bridge is likely to be generated, and this bridge becomes a brazing material pool, which causes a problem when screwed.
[0030]
Further, the length of the notch 5 in the thickness direction of the frame body 4, that is, the so-called depth is preferably 0.1 to 1.5 mm, and if it is less than 0.1 mm, the brazing material pool is likely to occur when the brazing material is excessive. Become. On the other hand, when the thickness exceeds 1.5 mm, the bonding area between the base body 1 and the frame body 4 is reduced, so that the bonding is impaired, and the semiconductor element 7 tends to be unable to be hermetically accommodated inside the semiconductor package. Therefore, the length of the cutout 5 in the thickness direction of the frame 4 is preferably 0.1 to 1.5 mm.
[0031]
The cross-sectional shape of the notch 5 may be various shapes such as a polygon, a circle, and an ellipse. In the case of a polygon, the corner may have R (arc-shaped concave curved surface).
[0032]
The notch 5 effectively prevents the occurrence of brazing material accumulation in the peripheral portion of the screw mounting portion 1b, and as a result, the lower surface of the semiconductor package is completely adhered to the upper surface of the external electric circuit board, thereby It has a function to improve the effect. In addition, due to the residual thermal stress due to the difference in thermal expansion coefficient after joining the base body 1 and the frame body 4, the base body 1 having a lower elastic modulus than that of the frame body 4 is warped and deformed, and the lower surface of the base body 1 is set to the external electric circuit board. It also has a function of effectively preventing it from being difficult to be completely adhered and fixed.
[0033]
That is, the notch portion 5 also has a function of relieving thermal stress at the time of joining the base body 1 and the frame body 4, and has an excellent effect of effectively preventing warpage deformation of the base body 1 after the joining. .
[0034]
In addition, in order to fix the semiconductor package to the external electric circuit board completely in close contact with each other, when the screw is tightened and firmly fixed, the lower surface of the base body 1, particularly directly under the mounting portion 1a, is likely to be warped and deformed easily. . As a result, problems such as the fixing of the semiconductor element 7 and the mounting portion 1a being impaired and the occurrence of breakage such as cracks in the frame 4 occur, and the airtightness and operability of the semiconductor element 7 are impaired. It becomes. The notch 5 functions effectively as a means for solving such a problem.
[0035]
Thus, by providing the notch 5, it is possible to prevent the occurrence of brazing material accumulation, complete adhesion between the semiconductor package and the external electric circuit board, and avoid an increase in size of the semiconductor package. Further, it is possible to prevent the occurrence of residual thermal stress after the base body 1 and the frame body 4 are joined, and to secure the semiconductor package to the external electric circuit board.
[0036]
In the present invention, a lid (not shown) is joined to the upper surface of the frame 4 with a low melting point brazing material such as Au-Sn, effectively preventing deterioration of operability due to oxidation of the semiconductor element 7, The semiconductor element 7 is hermetically sealed.
[0037]
In the semiconductor package of the present invention, the inside and outside of a pair of opposing side portions are electrically connected to the upper surface of the base 1 made of a metal material and having the screw mounting portion 1b so as to surround the mounting portion 1a of the semiconductor element 7. A frame 4 having an input / output unit 2 that is electrically connected is attached with a brazing material, and the screw mounting portion 1b protrudes outward from the outer peripheral surface of the frame body 4, and the screw mounting portion on the outer peripheral surface of the frame body 4 A feature is that a notch 5 is formed from the lower side of the outer peripheral surface of the frame body 4 to the lower surface of the frame body 4 at a portion closest to 1b.
[0038]
The semiconductor element 7 is bonded and fixed to such a semiconductor package via an adhesive such as a resin adhesive or brazing material, and the electrode of the semiconductor element 7 is connected to the metallized layer 2b inside the semiconductor package via a bonding wire. Thereafter, a lid is bonded to the upper surface of the frame 4 with a low melting point brazing material such as Au—Sn, whereby a semiconductor device as a product is obtained.
[0039]
Thus, according to the present invention, it is possible to effectively prevent the brazing material pool around the screw mounting portion 1b, so that the external electric circuit board and the semiconductor package can be well fixed and the semiconductor element 7 can be kept for a long time. It can operate normally and stably.
[0040]
In addition, this invention is not limited to the said embodiment, It does not have any trouble in making a various change within the range which does not deviate from the summary of this invention.
[0041]
For example, if the notch 5 has the shape of the above embodiment, the metallized metal layer 3 may be formed on the inner surface, and even in that case, brazing material accumulation can be effectively prevented. Further, in this case, electromagnetic waves from the outside can be shielded more than in the case of the above embodiment. Further, the notch 5 may be formed on the outer peripheral surface of the frame 4 so as to penetrate the upper and lower surfaces of the frame 4. In that case, if the metallized metal layer 3 is formed on the inner surface of the notch part 5, the brazing material is wetted on the inner surface of the notch part 5 having a large area, so that the brazing material is less likely to leak to the outside of the frame 4 at the notch part 5, Formation of the brazing material pool outside the frame body 4 can be further effectively prevented.
[0042]
Further, the semiconductor element 7 may be an optical semiconductor element that operates by an optical signal, such as an LD (semiconductor laser), a PD (photodiode), etc. In this case, the container for storing the optical semiconductor element is an optical fiber or optical fiber. An optical semiconductor package for mounting an optical component such as an isolator is obtained.
[0043]
【The invention's effect】
In the present invention, the screw mounting portion of the base body protrudes outward from the outer peripheral surface of the frame body, and the frame body from the lower side of the outer peripheral surface of the frame body to the portion closest to the screw mounting portion of the outer peripheral surface of the frame body A notch is formed to prevent the brazing material from spreading from the joint between the base and the frame to the screw mounting portion over the lower surface of the substrate, thereby preventing the occurrence of brazing material pool around the screw mounting portion. As a result, the semiconductor package And the external electric circuit board can be completely adhered. In addition, it is possible to avoid an increase in the size of the semiconductor package, to prevent generation of residual thermal stress after joining the base body and the frame, and to improve the fixing of the semiconductor package to the external electric circuit board.
[Brief description of the drawings]
FIG. 1 is a perspective view showing an example of an embodiment of a semiconductor package of the present invention.
2 is an enlarged perspective view of a main part of a peripheral part of a frame body and a screw attachment part of FIG. 1;
FIG. 3 is a perspective view of a conventional semiconductor package.
FIG. 4 is a perspective view of a conventional semiconductor package.
[Explanation of symbols]
1: Base 1a: Placement part 1b: Screw mounting part 2: Input / output part 4: Frame body 5: Notch part 7: Semiconductor element

Claims

A base body made of a substantially rectangular metal plate, having a mounting portion on which the semiconductor element is mounted on the upper surface, and provided with a screw mounting portion made of a through hole or a notch penetrating the upper and lower surfaces on the opposite side portion; In the package for housing a semiconductor element, comprising: a frame body having an input / output part electrically connected to the inside and outside of the side part, which is brazed to surround the mounting part on the upper surface of the substrate; Protrudes outward from the outer peripheral surface of the frame body, and corresponds to a tip of the outer peripheral surface of the frame body in the vicinity of the screw mounting portion on the center side of the upper surface of the base body of the screw mounting portion. Further, a notch portion is formed from the lower side of the outer peripheral surface of the frame body to the lower surface of the frame body to prevent the brazing material from spreading from the joint portion of the base body and the frame body to the screw mounting portion. Package for semiconductor element storage

2. The package for housing a semiconductor element according to claim 1, wherein the frame is made of ceramics, and a metallized metal layer is formed on an inner surface of the notch.