JP2004207539A

JP2004207539A - Electronic component storage container and electronic device

Info

Publication number: JP2004207539A
Application number: JP2002375745A
Authority: JP
Inventors: Sadakatsu Yoshida; 定功吉田
Original assignee: Kyocera Corp
Current assignee: Kyocera Corp
Priority date: 2002-12-26
Filing date: 2002-12-26
Publication date: 2004-07-22

Abstract

<P>PROBLEM TO BE SOLVED: To provide a container for housing an electronic component which ensures air tightness of an electronic device even if the device is heated at the temperatures of 230-240°C when it is mounted on an external electronic circuit or the like, and uses leadless solder having superior corrosion resistance. <P>SOLUTION: The container for housing the electronic component comprises: a substrate 5 having in its upper face a recess in which a mounting part for mounting the electronic component 6 on the bottom face is formed; a metallized layer 5a and a gold layer thereon both of which are formed around the entire periphery of the recess in the upper face of the substrate 5; and a lid 1 that is bonded to the gold layer by heating and melting a solder layer 3 essentially composed of tin which is adhered around the entire periphery of the under surface of the lid 1. The weight ratio of tin in the solder layer 3 to gold in the gold layer is 7:3 to 40:1. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

【０００１】
【発明の属する技術分野】
本発明は、半導体素子や圧電振動子等の電子部品を気密に封止して収納するための電子部品収納用容器に関する。
【０００２】
【従来の技術】
従来、ＩＣ，ＬＳＩ等の半導体素子や圧電振動子等の電子部品を収納するための電子部品収納用容器（以下、容器ともいう）は、例えば酸化アルミニウム質焼結体（アルミナセラミックス）等の電気絶縁材料から成り、その上面の略中央部に電子部品を収容するための凹部およびその周辺から下面にかけて導出したタングステンやモリブデン等の高融点金属から成る複数のメタライズ配線層を有し、上面の外周部に封止用のメタライズ層が被着された基体を備えており、基体の上面の外周部に、下面の外周部に半田層等の封止材が被着された金属等から成る蓋体が接合される。
【０００３】
そして、基体の凹部底面に電子部品を接着剤を介して接着するとともに電子部品の各電極をボンディングワイヤ等を介してメタライズ配線層に接続し、しかる後、基体のメタライズ層に蓋体の下面の外周部に被着させておいた封止材が当接するように位置合わせを行い、窒素雰囲気等の不活性雰囲気中でメタライズ層と封止剤を加熱溶融一体化させ、基体と蓋体とから成る容器を気密に封止することによって最終製品としての電子装置となる。
【０００４】
なお、このような従来の電子装置においては、基体と蓋体とを接合する封止材として、金を80重量％含む金−錫合金や鉛を主成分とする半田が使用されていた。
【０００５】
しかしながら、金を80重量％含む金−錫合金を使った場合、製品の価格が高くなるため、金−錫合金を使用できる製品が限られてしまうという問題点があった。
【０００６】
また、鉛を主成分とする半田は、それに含まれる鉛が環境汚染物質に指定され、例えば鉛を含有する半田を使用した電子装置が屋外に廃棄もしくは放置され風雨に曝された場合、環境中に鉛が溶け出し環境を汚染する危険性があり、近年、地球環境保護運動の高まりの中で鉛を含有しない封止材が要求されるようになってきた。
【０００７】
そこで、人体に対して有害である鉛を用いない各種封止材が開発され提案されてきた。このような封止材として、例えば錫、ビスマス−銀、亜鉛−アルミニウム等を主成分とする各種半田が採用されている。
【０００８】
【特許文献１】
特開2000−307228号公報
【０００９】
【発明が解決しようとする課題】
しかしながら、錫−銀、錫−亜鉛等の錫を主成分とする半田は、−55〜125℃の温度サイクル条件下での耐熱疲労性には優れた信頼性を示すものの、これらの半田は、その融点がいずれも225℃以下であり、この半田を基体と蓋体とを気密に封止する封止材として使用した場合、封止材に電子装置を外部電気回路等に実装する際の230〜240℃の熱が加わると封止材自体が溶融してしまい、電子装置内部の気密封止が破れるという問題点を有していた。
【００１０】
また、ビスマス−銀を主成分とする半田は、−55〜125℃の温度サイクル条件下での耐熱疲労特性に劣り気密信頼性に欠けるため、電子装置の気密封止に用いるには不適当であるという問題点があった。
【００１１】
さらに、亜鉛−アルミニウムを主成分とする半田は、空気中に放置した場合に腐食が進行しやすく長期の気密信頼性に欠け、電子装置の気密封止用に用いるには、これもまた不適当であるという問題点があった。
【００１２】
したがって、本発明は上記従来の問題点に鑑み完成されたもので、その目的は、電子装置を外部電気回路等に実装する際に230〜240℃の熱が加わっても電子装置の気密性が確保でき、封止材自体の耐食性にも優れ、さらに鉛を含有しない封止材を用いた電子部品収納用容器を提供することにある。
【００１３】
【課題を解決するための手段】
本発明の電子部品収納用容器は、上面に形成された凹部の底面に電子部品が搭載される搭載部が形成された基体と、該基体の上面の前記凹部の周囲に全周にわたって形成されたメタライズ層およびその上の金層と、該金層に下面の外周部に全周にわたって被着された錫を主成分とする半田層が加熱溶融されて接合される蓋体とを具備する電子部品収納用容器であって、前記半田層に含まれる錫と前記金層の金との重量比が７：３〜40：１であることを特徴とする。
【００１４】
本発明の電子部品収納用容器は、半田層に含まれる錫と金層の金との重量比が７：３〜40：１であることから、基体と蓋体とを接合する際に半田層が加熱溶融されて金層の金を含むこととなり、その結果、半田層は融点が250℃以上の金を含む合金となることから、250℃以上の耐熱性のある電子装置を製作することができる。
【００１５】
また、本発明の電子部品収納用容器を電子装置と成して外部電気回路基板等に接続する際に、基体と蓋体との接合部に230〜240℃の熱が加わったとしても、接合部の半田層が溶融して電子部品収納用容器の気密封止が破れてしまうことはなく、気密信頼性の高い電子部品収納用容器とすることができる。
【００１６】
また本発明の電子部品収納用容器は、上面に形成された凹部の底面に電子部品が搭載される導体層から成る搭載部が形成された基体と、該基体の上面の前記凹部の周囲に全周にわたって形成されたメタライズ層およびその上の金層と、該金層に下面の外周部に全周にわたって被着された金−錫合金から成る半田層が加熱溶融されて接合される蓋体とを具備する電子部品収納用容器であって、前記半田層に含まれる錫と、前記半田層に含まれる金および前記金層の金との重量比が７：３〜40：１であることを特徴とする。
【００１７】
本発明の電子部品収納用容器は、金−錫合金から成る半田層に含まれる錫と、半田層に含まれる金および金層の金との重量比が７：３〜40：１であることから、基体と蓋体とを接合する際に半田層が加熱溶融されて金層の金を含むこととなり、その結果、半田層は金の含有量が増大して容易に融点が250℃以上の金を含む合金となることから、250℃以上の耐熱性のある電子装置を容易に製作することができる。
【００１８】
本発明の電子装置は、本発明の電子部品収納用容器と、前記基体の前記凹部の底面に搭載部に搭載された電子部品と、前記基体の上面の前記凹部の周囲に接合された蓋体とを具備したことを特徴とする。
【００１９】
本発明の電子装置は、上記の構成により、基体と蓋体との接合部が250℃以上の耐熱性のあるものとなり、電子装置を外部電気回路基板等に接続する際に基体と蓋体との接合部に230〜240℃の熱が加わったとしても、接合部の半田層が溶融して気密封止が破れることはなく、したがって気密信頼性の高い電子装置となる。
【００２０】
【発明の実施の形態】
本発明の電子部品収納用容器を以下に詳細に説明する。図１は、本発明の容器の実施の形態を示し、容器の基体に接合される蓋体の断面図である。図１において、１は蓋体、３は半田層である。図２は、本発明の電子装置の実施の形態の例を示す断面図である。図２おいて、４は容器、５は基体、５ａはメタライズ層、６は電子部品６である。
【００２１】
本発明の容器は、上面に形成された凹部の底面に電子部品６が搭載される導体層から成る搭載部が形成された基体５と、基体５の上面の凹部の周囲に全周にわたって形成されたメタライズ層５ａおよびその上の金層と、金層に下面の外周部に全周にわたって被着された錫を主成分とする半田層３が加熱溶融されて接合される蓋体１とを具備し、半田層３に含まれる錫と金層の金との重量比が７：３〜40：１である。
【００２２】
半田層３において、錫：金＝７：３の比よりも金が多くなると、合金の融点が高くなることにより、合金の流れが悪くなり、電子部品６が熱損傷する可能性のある340℃以上でないと封着ができなくなる。錫：金＝40：１の比よりも錫が多くなると、低融点の錫が多くなるため耐熱性が劣化し易くなる。
【００２３】
本発明の基体５は、上面の中央部に電子部品６を収容するための凹部が設けられており、この凹部の底面の搭載部に電子部品６がガラス、樹脂、ろう材等の接着剤を介して接着固定される。また、基体５の凹部の底面より外周部にかけて複数のメタライズ配線層（図示せず）が被着形成されており、このメタライズ配線層は、その凹部の底面に位置する部位には電子部品６の各電極がボンディングワイヤを介して電気的に接続され、外部に導出された部位は外部電気回路（図示せず）に電気的に接続されている。さらに、基体５の上面の凹部の周囲には、蓋体１を接合するためのメタライズ層５ａが被着されている。
【００２４】
この基体５は、酸化アルミニウム質焼結体（アルミナセラミックス），ムライト質焼結体，窒化アルミニウム質焼結体，炭化珪素質焼結体，ガラスセラミックス等の焼結体（セラミックス）、樹脂等の電気的絶縁材料から成る。基体５が例えば酸化アルミニウム質焼結体から成る場合、先ずアルミナ（Ａｌ₂Ｏ₃），シリカ（ＳｉＯ₂），カルシア（ＣａＯ），マグネシア（ＭｇＯ）等の原料粉末に適当な有機溶剤，溶媒を添加混合して泥漿状と成し、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でシート状に成形してセラミックグリーンシート（以下、グリーンシートともいう）を得、その後グリーンシートを所定形状に打ち抜き加工するとともに複数枚積層し、約1600℃の温度で焼成することにより製作される。
【００２５】
また、メタライズ配線層およびメタライズ層５ａは、タングステン，モリブデン，マンガン等の高融点金属から成り、これらの粉末に有機溶剤，溶媒を添加混合した金属ペーストをそれぞれグリーンシートの所定位置に従来周知のスクリーン印刷法により所定パターンに被着形成させておき、グリーンシートと同時焼成することにより形成される。
【００２６】
なお、メタライズ層５ａは、その表面に耐食性に優れ、半田等のろう材との濡れ性の良好な金層をめっき法等により0.1〜３μｍの厚さに被着させておく。
【００２７】
そして、基体５の上面の凹部の周囲に形成されたメタライズ層５ａ上の金層に、蓋体１がその下面外周部に被着された半田層３を介して接合される。このとき、半田層３に含まれる錫と金層の金との重量比が７：３〜40：１であるようにしておくことによって、基体５と蓋体１との接合部は融点が250〜300℃程度となり、250℃以上の耐熱性を確保することができる。
【００２８】
本発明の蓋体１は、例えば42アロイ（Ｆｅ42−Ｎｉ合金）やＦｅ−Ｎｉ−Ｃｏ合金等の金属、または基体５と同様の酸化アルミニウム質焼結体，ムライト質焼結体，窒化アルミニウム質焼結体，炭化珪素質焼結体，ガラスセラミックス等の焼結体から成る。蓋体２が金属から成る場合、蓋体２と成る母材を蓋体２に対応した形状（四角形や円形等）を有する打ち抜き型で打ち抜くことによって製作される。また、蓋体２がセラミックスから成る場合、基体５と同様な上記方法によって製作される。
【００２９】
また、蓋体２の半田層３が被着される領域には、下地金属層として、タングステン，モリブデン，マンガン等から成るメタライズ層と、その上に形成されたニッケル，金等のめっき層が形成される。なお、蓋体２が金属から成る場合にも、半田層３が被着される領域に、下地金属層として上記メタライズ層とその上に形成された上記めっき層が形成されていてもよい。
【００３０】
本発明の半田層３は錫を主成分とするものであるが、半田層３としては、錫を96.5重量％含み銀を3.5重量％含む共晶合金（以下、錫96.5−銀3.5共晶合金というように記す）、錫99.25−銅0.75合金、錫95.75−銀3.5−銅0.75合金、錫92−亜鉛８合金、錫99.3−銅0.7合金等の鉛を含有せず錫を主成分とする半田が用いられる。
【００３１】
なお、このような錫を主成分とする半田としては、電子部品６の熱的保護や残留応力の低減の観点から、できる限り低温で溶融可能なものが好ましく、例えば錫96.5−銀3.5共晶合金は溶融温度が約221℃であり、加熱溶融されて金層の金を含むことにより容易に融点が250℃以上の合金層となることから、好適に用いられる。
【００３２】
また、半田層３の厚みは１〜200μｍが好ましく、１μｍ未満では、溶融した際に基体との隙間を埋めることができず、気密性を確保できない傾向があり、200μｍを超えると、金層の金との合金化が不十分となり、接合部の耐熱性が低下する傾向がある。
【００３３】
また本発明の他の発明は、上面に形成された凹部の底面に電子部品６が搭載される導体層から成る搭載部が形成された基体５と、基体５の上面の凹部の周囲に全周にわたって形成されたメタライズ層５ａおよびその上の金層と、金層に下面の外周部に全周にわたって被着された金−錫合金から成る半田層３が加熱溶融されて接合される蓋体１とを具備し、半田層３に含まれる錫と、半田層３に含まれる金および金層の金との重量比が７：３〜40：１である。
【００３４】
金−錫合金から成る半田層３は、例えば金10−錫90合金等である。この場合、半田層３が加熱溶融された際に、半田層３に金層の金が拡散して半田層３中の金の含有量が増加し、基体５と蓋体１との接合部は容易に融点が250〜300℃程度となり、250℃以上の耐熱性を確保することができる。
【００３５】
この半田層３は以下の（ａ）〜（ｅ）のいずれかの方法により蓋体２に被着される。
【００３６】
（ａ）錫を主成分とする半田の粉末にフラックス，有機溶剤，溶媒を添加混合して得た半田ペーストを、蓋体２の下面の外周部に厚みが１〜200μｍとなるようにスクリーン印刷し、その後リフローし、洗浄してフラックスを除去することにより半田層３を形成する。
【００３７】
（ｂ）錫を主成分とする半田から成る厚み１〜200μｍのフィルムやシートを打ち抜いて枠状や環状の半田シートを作製し、それを還元ガス中で400℃で蓋体２に溶融密着させる方法により半田層３を形成する。
【００３８】
（ｃ）めっき法により錫を主成分とする半田を蓋体２に被着する方法により半田層３を形成する。
【００３９】
（ｄ）錫を主成分とする半田を溶融状態で蓋体２の材料のリボンに塗布することにより半田層３を形成する。得られた２層の金属板を蓋体１の形状に金型で打ち抜くことにより蓋体１が得られる。
【００４０】
（ｅ）蓋体１の材料のリボンに錫を主成分とする半田のリボンを重ねあわせ、全体を加圧圧延することにより半田層３を形成する。得られた２層の金属板を蓋体１の形状に金型で打ち抜くことにより蓋体１が得られる。
【００４１】
また、基体５と蓋体１との接合は、基体５のメタライズ層５ａ上の金層に蓋体１の半田層３が当接するようにして蓋体１を基体５上に載置し、しかる後、シール炉中において、蓋体１を上方から基体５に一定圧力で押し付けながらピーク温度が約250〜300℃の温度で窒素雰囲気中で0.5〜20分間保持して半田層３を加熱溶融させることにより、半田層３と金層の金とが合金化して、基体５に蓋体２が半田層３を介して気密に接合されることとなる。
【００４２】
なお、金層はＡｇ，Ｃｕ，Ｐｔ，Ｆｅ，Ｎｉ，Ｃｒ等の微量の不純物を含んでいてもよい。
【００４３】
かくして、本発明の容器は、基体５の凹部底面に電子部品６を接着剤等を介して接着するとともに電子部品６の各電極をボンディングワイヤ等を介してメタライズ配線層に接続し、しかる後、基体５と蓋体１とを半田層３を加熱溶融させて接合し気密に封止することによって、最終製品としての電子装置となる。
【００４４】
【実施例】
本発明の実施例について以下に説明する。
【００４５】
図１の蓋体１として、外形寸法が縦4.5ｍｍ×横4.5ｍｍ×厚さ0.15ｍｍのニッケルめっきした４２アロイ板を用意し、このニッケルめっきした４２アロイ板の下面の外周部に、錫を主成分とした各種半田（表１参照）から成る半田層３を、めっき法で0.5μ〜９μｍの種々の厚みで形成し、またはスクリーン印刷により20〜150μｍの種々の厚みで形成して、各種蓋体１のサンプルを作製した。
【００４６】
また、上面に凹部が形成された、外形寸法が縦５ｍｍ×横５ｍｍ×厚さ1.5ｍｍで、凹部の内寸法が3.7ｍｍであるアルミナセラミックスから成る基体５を用意し、凹部の底面にＷメタライズ層から成る搭載部を形成し、その搭載部に半導体素子を搭載した。また、基体５の上面の凹部の周囲に厚さ20μｍのＷメタライズ層、厚さ３μｍのニッケルめっき層、めっき法で形成された厚さ１μｍの金層を順次被着した。
【００４７】
そして、蓋体１の半田層３と基体５の金層とを当接させた状態で、封止炉中で窒素雰囲気中280℃程度に加熱し半田層３を溶融させて、蓋体１と基体５とを接合し封着した。
【００４８】
得られた電子装置の各種サンプル（１種あたり30個）の初期気密性と、250℃に加熱した場合の耐熱性を確認した結果を表1に示す。
【００４９】
なお、初期気密性は封着直後に気密性が保たれている場合を良好とした。気密性の確認は、一般的なバブルリーク法とヘリウムリーク法によって行なった。バブルリーク法は、サンプルを６×10⁵Ｐａのヘリウムガス中で１時間以上加圧した後に、125℃に加熱したフロリナートの不活性液体中に浸漬した場合に、泡の発生の有無で確認する方法であり、連続した泡の発生が無ければ合格となる。ヘリウムリーク法は、サンプルを６×10⁵Ｐａのヘリウムガス中で１時間以上加圧した後に、30分放置し、その後ヘリウムデテクターでサンプルから検出されるヘリウム量を測定する方法であり、上記の基体５、蓋体１の寸法であれば、検出されるヘリウム量が１×10^-9Ｐａ・ｍ³／秒以下であれば合格となる。
【００５０】
また、耐熱性は、250℃のヒーターブロック上にサンプルを1分載置し、その後に気密性が保たれている場合を良好とした。そして、30個すべてのサンプルが良好なものを○、不良が発生したものを×とした。
【００５１】
【表１】

【００５２】
表１より、本発明の範囲外のサンプルでは、初期封止性や耐熱性が劣化することが判明した。
【００５３】
なお、本発明は上記実施の形態および実施例に限定されず、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、上述の実施の形態では電子部品６として半導体素子を用いた例について説明したが、圧電振動子や弾性表面波素子等の電子部品６を収容した電子装置にも本発明の容器を適用可能であることは言うまでもない。
【００５４】
【発明の効果】
本発明の電子部品収納用容器は、半田層に含まれる錫と金層の金との重量比が７：３〜40：１であることから、基体と蓋体とを接合する際に半田層が加熱溶融されて金層の金を含むこととなり、その結果、半田層は融点が250℃以上の金を含む合金となることから、250℃以上の耐熱性のある電子装置を製作することができる。また、本発明の電子部品収納用容器を電子装置と成して外部電気回路基板等に接続する際に、基体と蓋体との接合部に230〜240℃の熱が加わったとしても、接合部の半田層が溶融して電子部品収納用容器の気密封止が破れてしまうことはなく、気密信頼性の高い電子部品収納用容器とすることができる。
【００５５】
また本発明の電子部品収納用容器は、金−錫合金から成る半田層に含まれる錫と、半田層に含まれる金および金層の金との重量比が７：３〜40：１であることから、基体と蓋体とを接合する際に半田層が加熱溶融されて金層の金を含むこととなり、その結果、半田層は金の含有量が増大して容易に融点が250℃以上の金を含む合金となることから、250℃以上の耐熱性のある電子装置を容易に製作することができる。
【００５６】
本発明の電子装置は、本発明の電子部品収納用容器と、基体の凹部の底面に搭載部に搭載された電子部品と、基体の上面の凹部の周囲に接合された蓋体とを具備したことにより、基体と蓋体との接合部が250℃以上の耐熱性のあるものとなり、電子装置を外部電気回路基板等に接続する際に基体と蓋体との接合部に230〜240℃の熱が加わったとしても、接合部の半田層が溶融して気密封止が破れることはなく、したがって気密信頼性の高い電子装置となる。
【図面の簡単な説明】
【図１】本発明の電子部品収納用容器について実施の形態の例を示し、電子部品収納用容器の基体に接合される蓋体の断面図である。
【図２】本発明の電子装置について実施の形態の一例を示す断面図である。
【符号の説明】
１：蓋体
３：半田層
４：電子部品収納用容器
５：基体
５ａ：メタライズ層
６：電子部品[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an electronic component storage container for hermetically sealing and storing electronic components such as a semiconductor element and a piezoelectric vibrator.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, an electronic component storage container (hereinafter, also referred to as a container) for storing an electronic component such as a semiconductor element such as an IC or an LSI or a piezoelectric vibrator is, for example, an electric device such as an aluminum oxide sintered body (alumina ceramics). A concave portion for accommodating an electronic component and a plurality of metallized wiring layers made of a refractory metal such as tungsten or molybdenum which are led out from the periphery to the lower surface in a substantially central portion of the upper surface of the upper surface. A cover made of a metal or the like having a base on which a metallizing layer for sealing is adhered, and a sealing material such as a solder layer adhered to the outer periphery of the lower surface on the outer periphery of the upper surface of the base Are joined.
[0003]
Then, the electronic component is bonded to the bottom surface of the concave portion of the base via an adhesive, and each electrode of the electronic component is connected to the metallized wiring layer via a bonding wire or the like. The metallization layer and the sealant are melted and integrated in an inert atmosphere such as a nitrogen atmosphere by performing alignment so that the sealant adhered to the outer peripheral portion is brought into contact with the sealant. The resulting container is hermetically sealed to provide an electronic device as a final product.
[0004]
In such a conventional electronic device, a gold-tin alloy containing 80% by weight of gold or a solder containing lead as a main component is used as a sealing material for joining the base and the lid.
[0005]
However, when a gold-tin alloy containing 80% by weight of gold is used, the price of the product becomes high, so that there is a problem that products that can use the gold-tin alloy are limited.
[0006]
In addition, the solder containing lead as a main component is designated as an environmental pollutant. For example, when an electronic device using the solder containing lead is discarded or left outdoors and exposed to the weather, it may cause environmental pollution. There is a danger that lead will melt out and pollute the environment, and in recent years, with the rise of the global environmental protection movement, a lead-free sealing material has been required.
[0007]
Therefore, various sealing materials that do not use lead, which is harmful to the human body, have been developed and proposed. As such a sealing material, for example, various solders containing tin, bismuth-silver, zinc-aluminum, or the like as a main component are employed.
[0008]
[Patent Document 1]
JP 2000-307228 A
[Problems to be solved by the invention]
However, tin-silver, tin-zinc and other solders containing tin as a main component exhibit excellent reliability in thermal fatigue resistance under temperature cycle conditions of −55 to 125 ° C., but these solders are: Each of the melting points is 225 ° C. or less, and when this solder is used as a sealing material for hermetically sealing the base and the lid, the sealing material is used for mounting an electronic device on an external electric circuit or the like. When heat of up to 240 ° C. is applied, the sealing material itself is melted, and the hermetic sealing inside the electronic device is broken.
[0010]
In addition, bismuth-silver-based solder is inferior in heat-resistant fatigue characteristics under temperature cycle conditions of -55 to 125 ° C and lacks hermetic reliability. There was a problem.
[0011]
Furthermore, the solder containing zinc-aluminum as a main component is susceptible to corrosion when left in the air and lacks long-term hermetic reliability, and is also unsuitable for use in hermetic sealing of electronic devices. There was a problem that.
[0012]
Therefore, the present invention has been completed in view of the above-mentioned conventional problems, and the object is to improve the airtightness of the electronic device even when heat of 230 to 240 ° C. is applied when the electronic device is mounted on an external electric circuit or the like. An object of the present invention is to provide a container for electronic component storage that can be secured, has excellent corrosion resistance of the sealing material itself, and further uses a sealing material containing no lead.
[0013]
[Means for Solving the Problems]
The electronic component storage container of the present invention is formed over the entire periphery of the base on which the mounting portion on which the electronic component is mounted is formed on the bottom surface of the recess formed on the upper surface, and around the recess on the upper surface of the base. An electronic component comprising: a metallized layer, a gold layer thereon, and a lid to which a solder layer containing tin as a main component, which is applied over the entire outer periphery of a lower surface of the gold layer, is heated and melted and joined. A storage container, wherein a weight ratio of tin contained in the solder layer to gold of the gold layer is 7: 3 to 40: 1.
[0014]
Since the weight ratio of tin contained in the solder layer to gold in the gold layer is 7: 3 to 40: 1, the electronic component storage container of the present invention can be used to bond the solder layer to the base and the lid. Is heated and melted to contain the gold in the gold layer, and as a result, the solder layer becomes an alloy containing gold with a melting point of 250 ° C or higher, so that it is possible to manufacture an electronic device having heat resistance of 250 ° C or higher. it can.
[0015]
Further, when the electronic component storage container of the present invention is formed into an electronic device and connected to an external electric circuit board or the like, even if heat of 230 to 240 ° C. is applied to the bonding portion between the base and the lid, the bonding is performed. Since the solder layer of the portion does not melt and the hermetic sealing of the electronic component storage container is broken, an electronic component storage container with high airtight reliability can be obtained.
[0016]
Further, the electronic component storage container of the present invention has a base on which a mounting portion formed of a conductor layer on which an electronic component is mounted is formed on the bottom surface of a concave portion formed on the upper surface, and a base formed on the upper surface of the base around the concave portion. A metallized layer formed over the circumference and a gold layer thereon, and a lid to which a solder layer made of a gold-tin alloy, which is applied to the outer circumference of the lower surface of the gold layer over the entire circumference, is heated and melted and joined. Wherein the weight ratio of tin contained in the solder layer to gold contained in the solder layer and gold of the gold layer is 7: 3 to 40: 1. Features.
[0017]
In the electronic component container of the present invention, the weight ratio of tin contained in the solder layer made of a gold-tin alloy to gold contained in the solder layer and gold of the gold layer is 7: 3 to 40: 1. Therefore, when joining the base and the lid, the solder layer is heated and melted and contains the gold of the gold layer, and as a result, the melting point of the solder layer is easily increased due to an increase in the content of gold and a melting point of 250 ° C. or higher. Since the alloy contains gold, an electronic device having heat resistance of 250 ° C. or higher can be easily manufactured.
[0018]
An electronic device according to the present invention includes an electronic component storage container according to the present invention, an electronic component mounted on a mounting portion on a bottom surface of the concave portion of the base, and a lid joined to the upper surface of the base around the concave portion. And characterized in that:
[0019]
According to the electronic device of the present invention, the junction between the base and the lid has heat resistance of 250 ° C. or higher due to the above configuration. When the electronic device is connected to an external electric circuit board or the like, the base and the lid are connected to each other. Even if heat of 230 to 240 ° C. is applied to the joint, the solder layer at the joint is not melted and hermetic sealing is not broken, thus providing an electronic device with high hermetic reliability.
[0020]
BEST MODE FOR CARRYING OUT THE INVENTION
The electronic component storage container of the present invention will be described in detail below. FIG. 1 shows an embodiment of the container of the present invention, and is a cross-sectional view of a lid joined to a base of the container. In FIG. 1, 1 is a lid, and 3 is a solder layer. FIG. 2 is a sectional view showing an example of an embodiment of the electronic device of the present invention. In FIG. 2, reference numeral 4 denotes a container, 5 denotes a base, 5a denotes a metallized layer, and 6 denotes an electronic component 6.
[0021]
The container of the present invention is formed on a base 5 having a mounting portion formed of a conductor layer on which an electronic component 6 is mounted on the bottom surface of a concave portion formed on the upper surface, and is formed over the entire periphery of the concave portion on the upper surface of the base 5. Metallized layer 5a, a gold layer thereon, and a lid 1 to which a solder layer 3 containing tin as a main component, which is applied over the entire outer periphery of the lower surface of the gold layer, is melted and joined. The weight ratio between tin contained in the solder layer 3 and gold in the gold layer is 7: 3 to 40: 1.
[0022]
If the amount of gold in the solder layer 3 is higher than the ratio of tin: gold = 7: 3, the melting point of the alloy is increased, so that the flow of the alloy is deteriorated and the electronic component 6 may be thermally damaged at 340 ° C. Otherwise, sealing will not be possible. If the ratio of tin to gold is higher than the ratio of tin: gold = 40: 1, the heat resistance tends to deteriorate due to the increase in tin having a low melting point.
[0023]
The base 5 of the present invention is provided with a concave portion for accommodating the electronic component 6 at the center of the upper surface, and the electronic component 6 is provided with an adhesive such as glass, resin, brazing material or the like on the mounting portion on the bottom surface of the concave portion. It is bonded and fixed through. In addition, a plurality of metallized wiring layers (not shown) are formed on the base 5 from the bottom surface of the concave portion to the outer peripheral portion. Each electrode is electrically connected via a bonding wire, and a portion led out is electrically connected to an external electric circuit (not shown). Further, a metallized layer 5a for bonding the lid 1 is provided around the concave portion on the upper surface of the base 5.
[0024]
The substrate 5 is made of a sintered body (ceramic) such as an aluminum oxide sintered body (alumina ceramic), a mullite sintered body, an aluminum nitride sintered body, a silicon carbide sintered body, a glass ceramic, or a resin. It consists of an electrically insulating material. When the substrate 5 is made of, for example, an aluminum oxide sintered body, first, an appropriate organic solvent and a solvent are added to a raw material powder such as alumina (Al ₂ O ₃ ), silica (SiO ₂ ), calcia (CaO), and magnesia (MgO). The mixture was added and mixed to form a slurry, which was formed into a sheet by a well-known doctor blade method or calender roll method to obtain a ceramic green sheet (hereinafter also referred to as a green sheet). It is manufactured by punching into a plurality of pieces, laminating a plurality of pieces, and firing at a temperature of about 1600 ° C.
[0025]
The metallized wiring layer and the metallized layer 5a are made of a high melting point metal such as tungsten, molybdenum, manganese or the like. It is formed by adhering and forming a predetermined pattern by a printing method, and simultaneously firing with the green sheet.
[0026]
The metallized layer 5a is formed by depositing a gold layer having excellent corrosion resistance and good wettability with a brazing material such as solder on the surface to a thickness of 0.1 to 3 μm by plating or the like.
[0027]
Then, the lid 1 is joined to the gold layer on the metallized layer 5a formed around the concave portion on the upper surface of the base 5 via the solder layer 3 attached to the outer peripheral portion of the lower surface. At this time, by setting the weight ratio of tin contained in the solder layer 3 to gold of the gold layer to be 7: 3 to 40: 1, the junction between the base 5 and the lid 1 has a melting point of 250. It is about 300 ° C., and heat resistance of 250 ° C. or more can be secured.
[0028]
The lid 1 of the present invention is made of a metal such as a 42 alloy (Fe42-Ni alloy) or an Fe-Ni-Co alloy, or an aluminum oxide sintered body, a mullite sintered body, an aluminum nitride It is made of a sintered body such as a sintered body, a silicon carbide sintered body, and a glass ceramic. When the cover 2 is made of a metal, the cover 2 is manufactured by punching a base material forming the cover 2 with a punching die having a shape (such as a square or a circle) corresponding to the cover 2. When the lid 2 is made of ceramics, it is manufactured by the same method as that for the base 5.
[0029]
In a region of the lid 2 where the solder layer 3 is to be deposited, a metallized layer made of tungsten, molybdenum, manganese, or the like, and a plated layer of nickel, gold, or the like formed thereon are formed as base metal layers. Is done. Even when the lid 2 is made of metal, the metallized layer and the plating layer formed thereon may be formed as a base metal layer in the region where the solder layer 3 is applied.
[0030]
The solder layer 3 of the present invention contains tin as a main component. The solder layer 3 is made of a eutectic alloy containing 96.5% by weight of tin and 3.5% by weight of silver (hereinafter referred to as a tin 96.5-silver 3.5 eutectic alloy). Such as tin 99.25-copper 0.75 alloy, tin 95.75-silver 3.5-copper 0.75 alloy, tin 92-zinc 8 alloy, tin 99.3-copper 0.7 alloy, etc. Is used.
[0031]
As such a solder containing tin as a main component, a solder that can be melted at as low a temperature as possible from the viewpoint of thermal protection of the electronic component 6 and reduction of residual stress is preferable. For example, tin 96.5-silver 3.5 eutectic The alloy is preferably used because it has a melting temperature of about 221 ° C. and is easily melted by heating and containing gold in a gold layer to form an alloy layer having a melting point of 250 ° C. or more.
[0032]
Further, the thickness of the solder layer 3 is preferably 1 to 200 μm, and if it is less than 1 μm, the gap between the solder layer and the base cannot be filled when melting, and airtightness tends not to be secured. Alloying with gold becomes insufficient, and the heat resistance of the joint tends to decrease.
[0033]
Further, another aspect of the present invention provides a base 5 having a mounting portion formed of a conductive layer on which an electronic component 6 is mounted on a bottom surface of a concave portion formed on the upper surface, and an entire circumference around the concave portion on the upper surface of the base 5. Cover 1 to which a metallized layer 5a formed over the entire surface and a gold layer thereon and a solder layer 3 made of a gold-tin alloy, which is applied over the entire outer periphery of the lower surface of the gold layer, are melted and joined. And the weight ratio of tin contained in the solder layer 3 to gold contained in the solder layer 3 and gold of the gold layer is 7: 3 to 40: 1.
[0034]
The solder layer 3 made of a gold-tin alloy is, for example, a gold 10-tin 90 alloy. In this case, when the solder layer 3 is heated and melted, the gold of the gold layer diffuses into the solder layer 3 and the content of gold in the solder layer 3 increases, and the joint between the base 5 and the lid 1 is The melting point easily becomes about 250 to 300 ° C., and heat resistance of 250 ° C. or more can be secured.
[0035]
The solder layer 3 is attached to the lid 2 by any one of the following methods (a) to (e).
[0036]
(A) A solder paste obtained by adding a flux, an organic solvent, and a solvent to a solder powder containing tin as a main component and screen-printing the outer peripheral portion of the lower surface of the lid 2 so as to have a thickness of 1 to 200 μm. Then, the solder layer 3 is formed by reflowing and washing to remove the flux.
[0037]
(B) A frame or ring-shaped solder sheet is prepared by punching a film or sheet having a thickness of 1 to 200 μm made of solder containing tin as a main component, and the solder sheet is melted and adhered to the lid 2 at 400 ° C. in a reducing gas. The solder layer 3 is formed by the method.
[0038]
(C) The solder layer 3 is formed by applying a solder containing tin as a main component to the lid 2 by plating.
[0039]
(D) A solder layer 3 is formed by applying a solder containing tin as a main component in a molten state to a ribbon of the material of the lid 2. The lid 1 is obtained by punching out the obtained two-layer metal plate into the shape of the lid 1 with a die.
[0040]
(E) A solder ribbon mainly composed of tin is superimposed on the ribbon of the material of the lid 1, and the whole is rolled under pressure to form the solder layer 3. The lid 1 is obtained by punching out the obtained two-layer metal plate into the shape of the lid 1 with a die.
[0041]
The lid 5 is placed on the base 5 such that the solder layer 3 of the lid 1 is in contact with the gold layer on the metallized layer 5a of the base 5 by bonding the base 5 and the lid 1. Thereafter, in the sealing furnace, the solder layer 3 is heated and melted by pressing the lid 1 against the base 5 from above with a constant pressure and maintaining the temperature at a peak temperature of about 250 to 300 ° C. in a nitrogen atmosphere for 0.5 to 20 minutes. Thereby, the solder layer 3 and the gold of the gold layer are alloyed, and the lid 2 is hermetically joined to the base 5 via the solder layer 3.
[0042]
The gold layer may contain a trace amount of impurities such as Ag, Cu, Pt, Fe, Ni, and Cr.
[0043]
Thus, in the container of the present invention, the electronic component 6 is adhered to the bottom surface of the concave portion of the base 5 via an adhesive or the like, and each electrode of the electronic component 6 is connected to the metallized wiring layer via a bonding wire or the like. The base 5 and the lid 1 are joined by heating and melting the solder layer 3 and hermetically sealed to provide an electronic device as a final product.
[0044]
【Example】
An embodiment of the present invention will be described below.
[0045]
As a lid 1 of FIG. 1, a nickel-plated 42-alloy plate having an outer dimension of 4.5 mm × 4.5 mm × 0.15 mm in thickness is prepared, and tin is coated on the outer periphery of the lower surface of the nickel-plated 42-alloy plate. The solder layer 3 composed of various solders (see Table 1) as main components is formed in various thicknesses of 0.5 μm to 9 μm by plating or in various thicknesses of 20 μm to 150 μm by screen printing. A sample of the lid 1 was prepared.
[0046]
In addition, a base body 5 made of alumina ceramics having an outer dimension of 5 mm in length × 5 mm in width × 1.5 mm in thickness and an inner dimension of 3.7 mm in which a recess is formed on the upper surface is prepared, and a W metallization is formed on the bottom of the recess. A mounting portion composed of layers was formed, and a semiconductor element was mounted on the mounting portion. In addition, a W metallized layer having a thickness of 20 μm, a nickel plating layer having a thickness of 3 μm, and a gold layer having a thickness of 1 μm formed by a plating method were sequentially applied around the concave portion on the upper surface of the substrate 5.
[0047]
Then, in a state where the solder layer 3 of the lid 1 and the gold layer of the base 5 are in contact with each other, the solder layer 3 is melted by heating to about 280 ° C. in a nitrogen atmosphere in a sealing furnace, and The substrate 5 was joined and sealed.
[0048]
Table 1 shows the results of confirming the initial airtightness of various samples (30 pieces per type) of the obtained electronic devices and the heat resistance when heated to 250 ° C.
[0049]
The initial airtightness was determined to be good when airtightness was maintained immediately after sealing. The airtightness was confirmed by a general bubble leak method and a helium leak method. In the bubble leak method, when a sample is pressurized in helium gas of 6 × 10 ⁵ Pa for 1 hour or more, and then immersed in an inert liquid of Fluorinert heated to 125 ° C., the presence or absence of bubbles is confirmed. This is a method, and it passes if there is no generation of continuous bubbles. The helium leak method is a method in which a sample is pressurized in helium gas of 6 × 10 ⁵ Pa for 1 hour or more, then left for 30 minutes, and then the amount of helium detected from the sample is measured with a helium detector. If the dimensions of the base 5 and the cover 1 are the same, the test passes if the detected helium amount is 1 × 10 ⁻⁹ Pa · m ³ / sec or less.
[0050]
The heat resistance was determined to be good when the sample was placed on a heater block at 250 ° C. for 1 minute, and thereafter the airtightness was maintained. Then, all samples having good samples were evaluated as ○, and samples having defective samples were evaluated as ×.
[0051]
[Table 1]

[0052]
From Table 1, it was found that the samples outside the range of the present invention deteriorate in initial sealing property and heat resistance.
[0053]
It should be noted that the present invention is not limited to the above embodiments and examples, and various changes can be made without departing from the spirit of the present invention. For example, in the above-described embodiment, an example in which a semiconductor element is used as the electronic component 6 has been described. However, the container of the present invention can be applied to an electronic device containing the electronic component 6 such as a piezoelectric vibrator or a surface acoustic wave element. Needless to say,
[0054]
【The invention's effect】
Since the weight ratio of tin contained in the solder layer to gold in the gold layer is 7: 3 to 40: 1, the electronic component storage container of the present invention can be used to bond the solder layer to the base and the lid. Is heated and melted to contain the gold in the gold layer, and as a result, the solder layer becomes an alloy containing gold with a melting point of 250 ° C or higher, so that it is possible to manufacture an electronic device having heat resistance of 250 ° C or higher. it can. Further, when the electronic component storage container of the present invention is formed into an electronic device and connected to an external electric circuit board or the like, even if heat of 230 to 240 ° C. is applied to the bonding portion between the base and the lid, the bonding is performed. Since the solder layer of the portion does not melt and the hermetic sealing of the electronic component storage container is broken, an electronic component storage container with high airtight reliability can be obtained.
[0055]
Further, in the electronic component storage container of the present invention, the weight ratio of tin contained in the solder layer made of a gold-tin alloy to gold contained in the solder layer and gold in the gold layer is 7: 3 to 40: 1. Therefore, when joining the base and the lid, the solder layer is heated and melted and contains the gold of the gold layer, and as a result, the melting point of the solder layer is easily increased due to the increase of the gold content and the melting point is 250 ° C. or more. Since this alloy contains gold, it is possible to easily manufacture an electronic device having heat resistance of 250 ° C. or higher.
[0056]
The electronic device of the present invention includes the electronic component storage container of the present invention, an electronic component mounted on a mounting portion on the bottom surface of the concave portion of the base, and a lid joined around the concave portion on the upper surface of the base. Thereby, the junction between the base and the lid becomes heat-resistant at 250 ° C. or higher, and when the electronic device is connected to an external electric circuit board or the like, the junction between the base and the lid has a temperature of 230 to 240 ° C. Even if heat is applied, the solder layer at the bonding portion does not melt and hermetic sealing is not broken, and thus an electronic device with high hermetic reliability can be obtained.
[Brief description of the drawings]
FIG. 1 shows an example of an embodiment of an electronic component storage container of the present invention, and is a cross-sectional view of a lid joined to a base of the electronic component storage container.
FIG. 2 is a cross-sectional view illustrating an example of an embodiment of an electronic device of the invention.
[Explanation of symbols]
1: Lid 3: Solder layer 4: Container for storing electronic components 5: Base 5a: Metallized layer 6: Electronic components

Claims

A base on which a mounting portion on which an electronic component is mounted is formed on the bottom surface of the concave portion formed on the upper surface, a metallized layer formed over the entire periphery of the concave portion on the upper surface of the base and a gold layer thereon, An electronic component storage container comprising: a lid to which a tin-based solder layer adhered over the entire outer periphery of a lower surface of the lower surface of the gold layer is melted and joined; Wherein the weight ratio between tin and gold in the gold layer is 7: 3 to 40: 1.

A base on which a mounting portion made of a conductor layer on which an electronic component is mounted is formed on the bottom surface of the recess formed on the upper surface, a metallized layer formed over the entire periphery of the recess on the upper surface of the base, and An electronic component storage container comprising: a gold layer; and a lid to which a solder layer made of a gold-tin alloy adhered over the entire outer periphery of a lower surface of the gold layer is melted and joined. A weight ratio of tin contained in the solder layer to gold contained in the solder layer and gold of the gold layer is 7: 3 to 40: 1.

An electronic component storage container according to claim 1 or 2, an electronic component mounted on a mounting portion on a bottom surface of the concave portion of the base, and a lid joined to a periphery of the concave portion on an upper surface of the base. An electronic device comprising: