JP2004207673A

JP2004207673A - Electronic component

Info

Publication number: JP2004207673A
Application number: JP2003151605A
Authority: JP
Inventors: Masafumi Hisataka; 将文久高; Mitsutaka Touden; 光隆嶌田; Ko Matsuo; 香松尾
Original assignee: Kyocera Corp
Current assignee: Kyocera Corp
Priority date: 2002-10-30
Filing date: 2003-05-28
Publication date: 2004-07-22
Anticipated expiration: 2023-05-28
Also published as: JP4384443B2

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electronic component in which thermal melting of the internal solder and short circuits due to outflowing solder are prevented when the electronic component is mounted on a mother board. <P>SOLUTION: In order to form a specified interval between the surface of a base substrate 3 and one major surface of an electronic component element 2, a side face coating member 6b applied to the side face of the electronic component element 2 connected/secured to the surface of the base substrate 3 and to the outer circumferential surface of a solder joint member 5 has such a modulus of elasticity as the interval between the surface of the base substrate 1 and one major surface of the electronic component element 2 is varied while following the expansion of volume when a solder bump member 4 and the solder joint member 5 melt. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

【０００１】
【発明の属する技術分野】
本発明は、電子部品素子をハンダにてフリップチップ実装及び封止を行った電子部品装置に関するものである。
【０００２】
【従来の技術】
従来、電子部品装置の小型化の要求に伴い、電子部品素子の入出力電極にバンプを形成し、ベース基板の接続電極とファイスダウンにて接合・実装するフリップチップ実装を行った電子部品装置が知られている。
【０００３】
図５に、このような電子部品素子をハンダにてフリップチップ実装及び封止を行った電子部品装置として弾性表面波装置１００の断面図を示す。
【０００４】
電子部品素子である弾性表面波素子１００は、弾性表面波素子１０１の一方主面とベース基板１０２の表面との間に所定間隔を形成するようにハンダバンプ部材１０３にて、弾性表面波素子１０１の接続電極１０４とベース基板１０２の素子接続用電極１０５とが接続されている。また、弾性表面波素子１０１の外周には外周封止電極１０６が形成され、この部分とベース基板１０２の外周封止導体膜１０７とがハンダ接合部材１０８によって接合され、弾性表面波素子１０１の一方主面とベース基板１０２の表面との間の空隙が気密封止されている。この結果、弾性表面波素子１０１の一方主面に形成されたＩＤＴ電極は、水分の侵入等による変質を防ぐことができ、安定した信頼性性能を確保できる。
【０００５】
このように、ベース基板１０２と接続・封止を行った弾性表面波素子１０１の他方主面側から、エポキシ樹脂ペースト等を塗布、硬化処理することで外装樹脂層１０９を形成している。
【０００６】
【特許文献１】
特願２００２−２２２５８２号
【０００７】
【発明が解決しようとする課題】
しかしながら、上述の従来の弾性表面波装置１００においては、マザーボードへの実装時において、ハンダリフロー等の熱が弾性表面波装置１００の内部にも加わるため、弾性表面波素子１０１の外周封止電極１０６と、ベース基板１０２の外周封止導体膜１０７とを接合しているハンダ接合部材１０８にも熱が加わる。その結果、ハンダ接合部材１０８は、熱によって膨張するとともに再溶融時に大きく体積が膨張する。ハンダ接合部材１０８の外周面及び弾性表面波素子１０１の側面及び他方主面は、外装樹脂層１０９によって覆われており、強固に固定されているため、再溶融し体積が膨張したハンダ接合部材１０８は弾性表面波素子１０１とベース基板１０２との間の空隙を、内部方向に向かって流れ出すこととなり、その結果、ハンダバンプ部材１０３や接続電極１０４、あるいは素子接続電極１０５などと短絡する問題が発生していた。
【０００８】
この場合、再溶融したハンダの流れだしを防ぐために、ハンダ接合部材１０８とハンダバンプ部材１０３や接続電極１０４、あるいは素子接続電極１０５などとの間隔を十分とれば短絡は防止できるが、その結果、弾性表面波素子１０１やベース基板１０２の寸法の大型化を招き、製品の小型化対応には逆行する設計となってしまうため、効果的な問題解決が望まれていた。
【０００９】
本発明は上述の課題に鑑みて案出されたものであり、その目的は、マザーボードに実装する際、内部のハンダの再溶融による短絡を防止する電子部品装置を提供することにある。
【００１０】
【課題を解決するための手段】
上述の課題を解決するために本発明の電子部品装置は、一方主面に接続電極及び外周封止電極が形成された電子部品素子と、
ハンダバンプ部材を介して前記接続電極と接続する素子接続用電極、ハンダ接合部材を介して前記外周封止電極と接合する外周封止導体膜及び外部端子電極が夫々形成されたベース基板とを、前記ベース基板と前記電子部品素子との間に所定間隔が形成されるようにして接続するとともに、
前記電子部品素子の側面及び前記ハンダ接合部材の外周面に側面外装部材を、前記電子部品素子の他方主面に上面外装部材を配して成る電子部品装置において、前記側面外装部材は、前記ハンダバンプ部材及びハンダ接合部材の溶融温度で、該ハンダバンプ部材及びハンダ接合部材の体積膨張により発生する前記ベース基板と前記電子部品素子との間の間隔の変化に追従する弾性率を有することを特徴とする電子部品装置である。
【００１１】
また、前記側面外装部材は、熱可逆性を有する樹脂である。
【００１２】
また、前記側面外装部材は、温度２５℃における弾性率が３．５ＧＰａ〜６ＧＰａであり、且つ温度２３０℃における弾性率が０．２ＧＰａ〜０．８ＧＰａである。
【００１３】
【作用】
本発明によれば、ベース基板と電子部品素子の一方主面との間に所定間隔を形成するようにして、ベース基板に電子部品素子が接続されるとともに、電子部品素子の側面及びハンダ接合部材外周面には側面外装部材が、電子部品素子の他方主面には上面外装部材が被覆されている。そして、この側面外装部材、ハンダバンプ部材及びハンダ接合部材の溶融温度で、ハンダバンプ部材及びハンダ接合部材の体積膨張により発生するベース基板と電子部品素子との間の間隔の変化に追従する弾性率を有している。即ち、電子部品装置をマザーボードに実装する際、ハンダリフロー等の熱でハンダバンプ部材及びハンダ接合部材が溶融し体積膨張が生じたとき、その体積膨張による応力によって、電子部品素子を上方に持ち上げる力が働く。このとき、側面外装部材にも同時に伸びが生して、ベース基板の表面と電子部品素子の一方主面との間の間隔の変化に追従する。従って、従来のようにハンダバンプ部材及びハンダ接合部材が再溶融したハンダが、電子部品素子とベース基板との空隙の内部方向に向かって流れ出し、短絡を発生させる恐れはない。
【００１４】
また本発明によれば、側面外装部材は熱可逆性樹脂であるため電子部品装置のマザーボードへの実装が終了し、電子部品装置の温度が常温に戻った時点で元の状態に復帰するため、元来の信頼性性能を損なうこともない。
【００１５】
【発明の実施の形態】
以下、本発明の電子部品装置を図面に基づいて詳説する。なお、説明にあたっては電子部品素子として弾性表面波素子を用いた電子部品装置の１つである弾性表面波装置を例にとって説明を行う。
【００１６】
図１は本発明の弾性表面波装置１の断面図であり、図２は弾性表面波装置１に用いるベース基板３の平面図である。
【００１７】
弾性表面波装置（電子部品装置）１は、弾性表面波素子（電子部品素子）２、ベース基板３、ハンダバンプ部材４、ハンダ接合部材５、外装部材６より構成されている。
【００１８】
弾性表面波素子２は弾性表面波共振子、弾性表面波フィルタなどが例示でき、水晶やニオブ酸リチウム、タンタル酸リチウムなどの圧電基板２０の一方主面上に図示しないインターデジタルトランスデューサー電極（本発明では櫛歯状電極及び反射器電極を含み、以下単にＩＤＴ電極という）が形成され、さらに、このＩＤＴ電極と接続する接続電極８が形成されている。また、この圧電基板２０の外周には全周にわたって、ＩＤＴ電極や接続電極８を取り囲むように環状の外周封止電極９が形成されている。これらの各電極は、例えばＡｌ、Ｃｕなどをフォトリソグラフィ技術により形成され、また、必要に応じてその表面にＣｒ、Ｎｉ、Ａｕなどの層が形成される。
【００１９】
ベース基板３は、図１、図２に示すように、例えば、ガラスーセラミック材料などの多層基板から成り、表面には、弾性表面波素子２の接続電極８と対向する素子接続用電極１０、及び外周封止電極９と対向する環状の外周封止導体膜１１が形成されている。また、ベース基板３の底面には、外部端子電極１２が形成されており、素子接続電極１０と外部端子電極１２とはビアホール導体１３を含む内部配線パターンにて接続されている。
【００２０】
ここで上述の弾性表面波素子２は、接続電極８とベース基板３の素子接続用電極１０とをハンダバンプ部材４によって、弾性表面波素子２の一方主面とベース基板３の表面との間に所定の空隙を形成すると同時に電気的接続を行う。また、外周封止電極９と外周導体膜１１とをハンダ接合部材５によって接合することで、弾性表面波素子２の一方主面とベース基板３の表面との間の空隙を封止し、空隙内部気密に保つことができ、湿気の侵入などによるＩＤＴ電極の劣化を防止する。
【００２１】
上述の弾性表面波素子２とベース基板３との接続・接合にあたっては、まず、ベース基板２に、それぞれハンダバンプ部材４とハンダ接合部材５を形成する。このハンダバンプ部材４とハンダ接合部材５は、それぞれ素子接続用電極１０の表面及び外周封止導体膜１１の表面にペースト状のハンダを塗布して形成するが、バンプ状の形状とするため、塗布したハンダに一次加熱処理及び洗浄処理を行う。これによって、塗布されたハンダは、素子接続用電極１０及び外周封止導体膜１１上で断面半円形状となり、さらに、不要なフラックス成分を除去することができる。そして、上述のバンプ状のハンダが形成されたベース基板３に弾性表面波素子２を載置し、リフロー処理を行うことによりハンダバンプ部材４によって電気的な接続を施し、ハンダ接合部材５によって機械的な接合を行うとともに気密的な封止を行う。これにより、ハンダバンプ部材４及びハンダ接合部材５の高さに相当する空隙が、弾性表面波素子２の一方主面とベース基板３の表面との間にでき、かつ、気密封止されるため、弾性表面波素子２の主面において安定した弾性表面波を振動させることができる。
【００２２】
そして、上述の、ベース基板３に電気的な接続及び機械的な接合が施された弾性表面波素子２には、他方主面側及び側面外周を覆って外装部材６が被着形成される。この外装部材６は、弾性表面波素子２の他方主面を覆う上面外装部材６ａと側面を覆う側面外装部材６ｂとから構成される。
【００２３】
ここで本発明の特徴的なことは、側面外装部材６ｂはハンダバンプ部材４及びハンダ接合部材５の溶融温度で体積膨張によるベース基板３の表面と弾性表面波素子２との間の間隔の変化に追従する弾性率を有していることである。即ち、弾性表面波装置１をマザーボードに実装する際、ハンダリフロー等の熱でハンダバンプ部材４及びハンダ接合部材５が溶融し体積膨張が生じる結果、弾性表面波素子１を上方に持ち上げる力が働く。このとき、側面外装部材６ｂに伸びが生じるためベース基板３の表面と弾性表面波素子１の一方主面との間は広がることができる。つまり、図３（ａ）に示すように、マザーボードに実装する前のベース基板３の表面と弾性表面波素子２の一方主面との間隔Ａは、マザーボードに実装時ハンダバンプ部材４及びハンダ接合部材５が溶融し体積膨張が生じる結果、図３（ｂ）に示す間隔Ｂとなる。このとき間隔Ａ＜間隔Ｂの関係となり、ベース基板３の表面と弾性表面波素子２の一方主面との間隔が広がることにより、ハンダバンプ部材４及びハンダ接合部材５の体積膨張（特に上下方向の動き）は妨げられることがない。よって、従来のように溶融したハンダが弾性表面波素子２とベース基板３との空隙を内部方向に向かって流れ出し短絡を発生させる恐れはない。
【００２４】
また、側面外装部材６ｂは、熱可逆性を有する例えば、エポキシ系樹脂成分であり、例えば、エポキシ樹脂成分に、無機フィラー、硬化剤成分とともにシリコーン樹脂弾性体成分を含有されている。そして、このシリコーン樹脂弾性成分を制御することにより弾性率の制御が可能となる。その弾性率は温度２５℃において３．５ＧＰａ〜６ＧＰａであり、かつ、温度２３０℃において０．２ＧＰａ〜０．８ＧＰａである。このような樹脂であれば、常温時、例えば２５℃において、外部衝撃から弾性表面波素子２を保護するのに必要な強度を有するとともに、樹脂の硬化時の収縮による反りも抑えることができる。加えて、ハンダバンプ部材４及びハンダ接合部材５が溶融する温度、例えば２３０℃において、弾性率が低下するため、ハンダバンプ部材４及びハンダ接合部材５の溶融時の体積膨張に追従して変形し、ベース基板３の表面と弾性表面波素子２の一方主面との間の間隔が変化することができる。よって、ハンダの流れ出しによる短絡不良もなく、弾性表面波素子２との密着強度も確保できる。
【００２５】
この側面外装部材６ｂにおいて、弾性率の異なる１０種類の樹脂を用いて評価を行った。この樹脂の２５℃における弾性率は１．５ＧＰａ〜８ＧＰａの間で異なっているものである。この１０種類の樹脂で側面外装部材６ｂを形成した弾性表面波装置１をそれぞれ作成した。同時に、反りの評価用として樹脂のみで３０ｍｍ角の基板もそれぞれ作成した。樹脂の硬化条件は、ともに１００℃で１時間、及び１５０℃で３時間の加熱を行った。次に、これら作成した弾性表面波装置１を１ｍの高さからコンクリート床上に自然落下させ、樹脂に割れや欠けの発生の有無を調べる落下試験と、３０ｍｍ角の基板の反りの量を測定した。これらの樹脂の２５℃における弾性率と落下試験の不良数及び基板反りの評価結果を表１に示す。
【００２６】
【表１】

【００２７】
樹脂の弾性率が小さいと、強度が劣化するため落下試験において割れや欠けの不良が発生する。弾性率が大きくなると、樹脂が硬化する際の収縮も大きく反りが発生し、弾性表面波装置としての電気特性に悪影響を及ぼす。従って、落下試験において不良の発生がなく、弾性表面波装置としての電気特性に悪影響を与えない反り量０．１ｍｍ以下の試料を合格と判定すると、試料番号４、５、６，７が合格となり、即ち、２５℃における弾性率が３．５ＧＰａ〜６ＧＰａの樹脂を選定すれば良い。
【００２８】
次に、同じ１０種類の樹脂で側面外装部材６ｂを形成した弾性表面波装置１と密着強度評価用として１．８ｍｍ角の弾性表面波素子２に樹脂層を形成した試料を用いて、ハンダリフロー処理を行いハンダ流れ出しによる短絡不良の発生数を調べるとともに、ダイシェア強度計にて樹脂の密着強度を測定した。このとき２３０℃における弾性率は０．１ＧＰａ〜１．３ＧＰａの間で異なっており、また、表１に示す試料番号と表２に示す試料番号は同一のものである。これらの樹脂の２３０℃における弾性率と短絡不良の発生数及び密着強度の評価結果を表１に示す。
【００２９】
【表２】

【００３０】
２３０℃での弾性率が小さいと、溶融したハンダの体積膨張を十分吸収できる為、ハンダ流れによる短絡不良は発生しない。しかし、弾性率が小さくなりすぎると、弾性表面波素子２との密着強度が低下する。従って、短絡不良の発生がなく、密着強度が十分とされるダイシェア強度４０Ｎ以上の試料を合格と判定すると、試料番号３，４、５，６が合格となり、即ち、２３０℃における弾性率が０．２ＧＰａ〜０．８ＧＰａである樹脂を選定すれば良い。
【００３１】
従って表１での判定と表２での判定を総合すると、２５℃での弾性率が３．５ＧＰａ〜６ＧＰａ、かつ２３０℃での弾性率が０．２ＧＰａ〜０．８ＧＰａである樹脂が使用可能で、両者を満足する樹脂として試料番号４，５、６の樹脂が使用できる。
【００３２】
尚、上述の実施例では、電子部品素子として弾性表面波素子を用いた弾性表面波装置の例を示したが、電子部品素子の種類を問わず、電子部品素子をハンダパンプ及びハンダ接合部材を用いてベース基板に接続し、且つ側面を外装部材で被覆した電子部品装置に対して本発明が広く適用できることは言うまでもない。
【００３３】
例えば、図４は、弾性表面波素子に代えて圧電共振素子を利用した圧電装置に本発明を適用した例を模式的に示す断面図である。
【００３４】
同図において、圧電装置７００は、圧電素子７、ベース基板３、ハンダバンプ部材４、ハンダ接合部材５、外装部材６より構成されており、圧電素子７以外の構成は図１に示した弾性表面波装置１と全く同じである。
【００３５】
圧電素子７は、圧電共振子や、複数の圧電共振子を組み合わせたフィルタやデュプレクサなどが例示でき、例えば、シリコンからなる基体７０の一方主面上に、間に窒化アルミニウムからなる圧電体層７１が介在されている一対の振動電極７２、この振動電極７２とそれぞれ接続される接続電極８が形成されている。さらに、基体７０の一方主面の外周には、圧電素子７とベース基板３との間に形成される間隙を気密封止する為の環状の外周封止電極９が形成されている。尚、振動電極７２の振動領域上には空隙７３が形成されており、振動の減衰が防止されている。
【００３６】
また、振動電極７２はモリブデン、タングステン、アルミニウムなどからなる表面層が、接続電極８と外周封止電極９は必要に応じてクロム層、ニッケル層、金層などからなる表面層がそれぞれ形成され、ハンダとの接続性を良好なものとしている。
【００３７】
上述のような構成とすることにより、圧電素子７は、圧電体層７１の厚み方向の振動を利用した共振器もしくはその共振器を複数個組み合わせたフィルタやデュプレクサなどとして動作し、このような圧電装置においても小型で信頼性の高い圧電装置を構成することができる。
【００３８】
【発明の効果】
本発明の電子部品装置によれば、電子部品素子の側面及びハンダ接合部材外周面に被着された側面外装部材が、ハンダバンプ部材及びハンダ接合部材の溶融時の体積膨張によるベース基板の表面と電子部品素子の一方主面との間の間隔の変化に追従する弾性率を有している。従って、電子部品装置をマザーボードに実装する際、ハンダリフロー等の熱でハンダバンプ部材及びハンダ接合部材が溶融し体積膨張が生じたとき、その体積膨張は妨げられることがないため、溶融したハンダの流れ出しがなく短絡を発生させる恐れがない。
【図面の簡単な説明】
【図１】本発明の電子部品装置の断面図である。
【図２】本発明の電子部品装置に用いるベース基板の平面図である。
【図３】本発明の電子部品装置の断面図であり、（ａ）はハンダバンプ部材及びハンダ接合部材の固化時の断面図であり、（ｂ）はハンダバンプ部材及びハンダ接合部材の溶融時の断面図である。
【図４】本発明を適用した圧電装置の構造を模式的に示す断面図である。
【図５】従来の電子部品装置の断面図である。
【符号の説明】
１・・・弾性表面波装置
２・・・弾性表面波素子
３・・・ベース基板
４・・・ハンダバンプ部材
５・・・ハンダ接合部材
６・・・外装部材
６ａ・・・上面外装部材
６ｂ・・・側面外装部材
７・・・圧電素子
８・・・接続電極
９・・・外周封止電極
１０・・・素子接続用電極
１１・・・外周封止導体膜[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an electronic component device in which electronic component elements are flip-chip mounted and sealed with solder.
[0002]
[Prior art]
Conventionally, in response to the demand for miniaturization of electronic component devices, flip-chip mounting, which forms bumps on the input / output electrodes of the electronic component elements and joins and mounts the connection electrodes on the base substrate by means of face down, has been developed. Are known.
[0003]
FIG. 5 is a cross-sectional view of a surface acoustic wave device 100 as an electronic component device in which such an electronic component element is flip-chip mounted and sealed with solder.
[0004]
The surface acoustic wave element 100, which is an electronic component element, is formed by solder bump members 103 so as to form a predetermined space between one main surface of the surface acoustic wave element 101 and the surface of the base substrate 102. The connection electrode 104 and the element connection electrode 105 of the base substrate 102 are connected. Further, an outer peripheral sealing electrode 106 is formed on the outer periphery of the surface acoustic wave element 101, and this portion and an outer peripheral sealing conductor film 107 of the base substrate 102 are joined by a solder joining member 108. A gap between the main surface and the surface of the base substrate 102 is hermetically sealed. As a result, the IDT electrode formed on one principal surface of the surface acoustic wave element 101 can prevent deterioration due to intrusion of moisture or the like, and can secure stable reliability performance.
[0005]
As described above, the exterior resin layer 109 is formed by applying and curing an epoxy resin paste or the like from the other main surface side of the surface acoustic wave element 101 connected and sealed to the base substrate 102.
[0006]
[Patent Document 1]
Japanese Patent Application No. 2002-22258 [0007]
[Problems to be solved by the invention]
However, in the above-described conventional surface acoustic wave device 100, heat such as solder reflow is also applied to the inside of the surface acoustic wave device 100 when mounted on a motherboard. Then, heat is also applied to the solder bonding member 108 that bonds the outer peripheral sealing conductor film 107 of the base substrate 102. As a result, the solder joint member 108 expands due to heat and expands significantly in volume when remelted. The outer peripheral surface of the solder bonding member 108 and the side surface and the other main surface of the surface acoustic wave element 101 are covered with the exterior resin layer 109 and are firmly fixed. Causes the gap between the surface acoustic wave element 101 and the base substrate 102 to flow inward, resulting in a short circuit with the solder bump member 103, the connection electrode 104, or the element connection electrode 105. I was
[0008]
In this case, in order to prevent the re-melted solder from flowing out, a short circuit can be prevented by providing a sufficient space between the solder bonding member 108 and the solder bump member 103, the connection electrode 104, or the element connection electrode 105. Since the dimensions of the surface acoustic wave element 101 and the base substrate 102 are increased, and the design is counter to the miniaturization of products, an effective solution of the problem has been desired.
[0009]
The present invention has been devised in view of the above-described problems, and an object of the present invention is to provide an electronic component device that prevents a short circuit due to remelting of internal solder when mounted on a motherboard.
[0010]
[Means for Solving the Problems]
In order to solve the above-described problems, an electronic component device of the present invention includes an electronic component element having a connection electrode and an outer peripheral sealing electrode formed on one main surface,
An element connection electrode connected to the connection electrode via a solder bump member, an outer peripheral sealing conductor film joined to the outer peripheral sealing electrode via a solder joining member, and a base substrate on which an external terminal electrode is formed, While connecting so that a predetermined interval is formed between the base substrate and the electronic component element,
An electronic component device comprising: a side surface exterior member disposed on a side surface of the electronic component element and an outer peripheral surface of the solder joint member; and an upper surface exterior member disposed on the other main surface of the electronic component element, wherein the side surface exterior member includes the solder bump. At the melting temperature of the member and the solder joint member, the solder bump member and the solder joint member have an elastic modulus that follows a change in the space between the base substrate and the electronic component element caused by volume expansion of the solder joint member. It is an electronic component device.
[0011]
Further, the side surface exterior member is a resin having thermoreversibility.
[0012]
Further, the side surface exterior member has an elastic modulus of 3.5 GPa to 6 GPa at a temperature of 25 ° C. and an elastic modulus of 0.2 GPa to 0.8 GPa at a temperature of 230 ° C.
[0013]
[Action]
According to the present invention, the electronic component element is connected to the base substrate so as to form a predetermined space between the base substrate and one main surface of the electronic component element, and the side surface of the electronic component element and the solder bonding member The outer peripheral surface is covered with a side surface exterior member, and the other main surface of the electronic component element is covered with an upper surface exterior member. At the melting temperature of the side surface exterior member, the solder bump member, and the solder bonding member, there is an elastic modulus that follows a change in the space between the base substrate and the electronic component element caused by the volume expansion of the solder bump member and the solder bonding member. are doing. That is, when mounting the electronic component device on the motherboard, when the solder bump member and the solder bonding member are melted by heat such as solder reflow and volume expansion occurs, a force for lifting the electronic component element upward due to the stress due to the volume expansion. work. At this time, elongation also occurs in the side surface exterior member at the same time, and follows the change in the distance between the surface of the base substrate and one main surface of the electronic component element. Therefore, unlike the related art, the solder in which the solder bump member and the solder bonding member are re-melted does not flow toward the inside of the gap between the electronic component element and the base substrate, and there is no danger of causing a short circuit.
[0014]
Further, according to the present invention, the mounting of the electronic component device on the motherboard is completed because the side exterior member is a thermoreversible resin, and the electronic component device returns to the original state when the temperature of the electronic component device returns to normal temperature. It does not impair the original reliability performance.
[0015]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, an electronic component device of the present invention will be described in detail with reference to the drawings. In the description, a surface acoustic wave device which is one of electronic component devices using a surface acoustic wave device as an electronic component device will be described as an example.
[0016]
FIG. 1 is a sectional view of a surface acoustic wave device 1 of the present invention, and FIG. 2 is a plan view of a base substrate 3 used in the surface acoustic wave device 1.
[0017]
The surface acoustic wave device (electronic component device) 1 includes a surface acoustic wave element (electronic component element) 2, a base substrate 3, a solder bump member 4, a solder bonding member 5, and an exterior member 6.
[0018]
The surface acoustic wave element 2 can be exemplified by a surface acoustic wave resonator, a surface acoustic wave filter, and the like. An interdigital transducer electrode (not shown) is formed on one main surface of a piezoelectric substrate 20 made of quartz, lithium niobate, lithium tantalate, or the like. In the present invention, a comb-shaped electrode and a reflector electrode are included, and the IDT electrode (hereinafter, simply referred to as an IDT electrode) is formed. Further, a connection electrode 8 connected to the IDT electrode is formed. Further, an annular outer peripheral sealing electrode 9 is formed on the entire outer periphery of the piezoelectric substrate 20 so as to surround the IDT electrode and the connection electrode 8. Each of these electrodes is formed of, for example, Al, Cu, or the like by a photolithography technique, and a layer of Cr, Ni, Au, or the like is formed on the surface as necessary.
[0019]
As shown in FIGS. 1 and 2, the base substrate 3 is made of, for example, a multi-layer substrate made of a glass-ceramic material or the like, and has on its surface an element connection electrode 10 facing the connection electrode 8 of the surface acoustic wave element 2, In addition, an annular outer peripheral sealing conductor film 11 facing the outer peripheral sealing electrode 9 is formed. An external terminal electrode 12 is formed on the bottom surface of the base substrate 3, and the element connection electrode 10 and the external terminal electrode 12 are connected by an internal wiring pattern including a via-hole conductor 13.
[0020]
In the surface acoustic wave element 2 described above, the connection electrode 8 and the element connection electrode 10 of the base substrate 3 are connected between one principal surface of the surface acoustic wave element 2 and the surface of the base substrate 3 by the solder bump member 4. An electrical connection is made at the same time as forming a predetermined gap. Further, by bonding the outer peripheral sealing electrode 9 and the outer peripheral conductor film 11 with the solder bonding member 5, the gap between one principal surface of the surface acoustic wave element 2 and the surface of the base substrate 3 is sealed. The inside can be kept airtight, and deterioration of the IDT electrode due to invasion of moisture or the like is prevented.
[0021]
In connecting and joining the surface acoustic wave element 2 and the base substrate 3, first, a solder bump member 4 and a solder joining member 5 are formed on the base substrate 2. The solder bump member 4 and the solder bonding member 5 are formed by applying paste solder to the surface of the element connection electrode 10 and the surface of the outer peripheral sealing conductor film 11, respectively. A primary heat treatment and a cleaning treatment are performed on the solder that has been made. As a result, the applied solder has a semicircular cross-section on the element connection electrode 10 and the outer peripheral sealing conductor film 11, and furthermore, unnecessary flux components can be removed. Then, the surface acoustic wave element 2 is placed on the base substrate 3 on which the above-mentioned bump-shaped solder is formed, and is electrically connected by the solder bump member 4 by performing a reflow process. And a hermetic seal. As a result, a gap corresponding to the height of the solder bump member 4 and the solder bonding member 5 is formed between one principal surface of the surface acoustic wave element 2 and the surface of the base substrate 3 and is hermetically sealed. A stable surface acoustic wave can be vibrated on the main surface of the surface acoustic wave element 2.
[0022]
The exterior member 6 is attached to the surface acoustic wave element 2 electrically connected and mechanically joined to the base substrate 3 so as to cover the other main surface and the outer periphery of the side surface. The exterior member 6 includes an upper exterior member 6a that covers the other main surface of the surface acoustic wave element 2 and a side exterior member 6b that covers the side surface.
[0023]
Here, the characteristic of the present invention is that the side surface exterior member 6b is capable of changing the distance between the surface of the base substrate 3 and the surface acoustic wave element 2 due to volume expansion at the melting temperature of the solder bump member 4 and the solder bonding member 5. That is, it has a following elastic modulus. That is, when the surface acoustic wave device 1 is mounted on a motherboard, heat such as solder reflow causes the solder bump member 4 and the solder bonding member 5 to melt and expand in volume, resulting in a force for lifting the surface acoustic wave element 1 upward. At this time, since the side surface exterior member 6b is elongated, the space between the surface of the base substrate 3 and one main surface of the surface acoustic wave element 1 can be expanded. That is, as shown in FIG. 3A, the distance A between the surface of the base substrate 3 and one main surface of the surface acoustic wave element 2 before being mounted on the motherboard is the solder bump member 4 and the solder bonding member when mounted on the motherboard. As a result of melting of 5 and volume expansion, the interval B shown in FIG. At this time, the relationship of the interval A <the interval B is satisfied, and the interval between the surface of the base substrate 3 and one main surface of the surface acoustic wave element 2 is increased, so that the volume expansion of the solder bump member 4 and the solder bonding member 5 (particularly, the vertical direction). Movement) is not hindered. Therefore, there is no possibility that the molten solder flows in the gap between the surface acoustic wave element 2 and the base substrate 3 toward the inside and causes a short circuit unlike the related art.
[0024]
The side surface exterior member 6b is, for example, an epoxy resin component having thermoreversibility. For example, the epoxy resin component contains a silicone resin elastic component together with an inorganic filler and a curing agent component. The elastic modulus can be controlled by controlling the silicone resin elastic component. Its elastic modulus is 3.5 GPa to 6 GPa at a temperature of 25 ° C., and 0.2 GPa to 0.8 GPa at a temperature of 230 ° C. With such a resin, at room temperature, for example, at 25 ° C., it has the strength necessary to protect the surface acoustic wave element 2 from an external impact, and also suppresses warping due to shrinkage of the resin during curing. In addition, at a temperature at which the solder bump member 4 and the solder joint member 5 melt, for example, at 230 ° C., the elastic modulus decreases, so that the solder bump member 4 and the solder joint member 5 deform according to the volume expansion at the time of melting, and The distance between the surface of the substrate 3 and one main surface of the surface acoustic wave element 2 can be changed. Therefore, there is no short-circuit failure due to solder flowing out, and the adhesion strength with the surface acoustic wave element 2 can be secured.
[0025]
This side exterior member 6b was evaluated using ten kinds of resins having different elastic moduli. The elastic modulus of the resin at 25 ° C. is different between 1.5 GPa and 8 GPa. The surface acoustic wave device 1 in which the side surface exterior member 6b was formed of the ten kinds of resins was manufactured. At the same time, 30 mm square substrates were also made of resin alone for evaluation of warpage. Regarding the curing conditions of the resin, heating was performed at 100 ° C. for 1 hour and at 150 ° C. for 3 hours. Next, the produced surface acoustic wave device 1 was naturally dropped on a concrete floor from a height of 1 m, a drop test for checking whether or not cracking or chipping occurred in the resin, and the amount of warpage of a 30 mm square substrate was measured. . Table 1 shows the elastic modulus of these resins at 25 ° C., the number of defects in the drop test, and the evaluation results of the substrate warpage.
[0026]
[Table 1]

[0027]
If the elastic modulus of the resin is small, the strength is deteriorated, so that cracking or chipping occurs in a drop test. When the elastic modulus increases, the resin shrinks when it cures, causing a large warp, which adversely affects the electrical characteristics of the surface acoustic wave device. Therefore, when a sample having a warpage of 0.1 mm or less, which does not cause a defect in the drop test and does not adversely affect the electrical characteristics of the surface acoustic wave device, is judged to be acceptable,

sample numbers

4, 5, 6, and 7 pass. That is, a resin having an elastic modulus at 25 ° C. of 3.5 GPa to 6 GPa may be selected.
[0028]
Next, using a sample in which a resin layer was formed on a surface acoustic wave device 1 having a side surface exterior member 6b made of the same ten kinds of resins and a surface acoustic wave element 2 having a 1.8 mm square for evaluation of adhesion strength, a solder reflow was performed. After the treatment, the number of occurrences of short-circuit failure due to solder flowing out was examined, and the adhesive strength of the resin was measured with a die shear strength meter. At this time, the elastic modulus at 230 ° C. is different between 0.1 GPa and 1.3 GPa, and the sample numbers shown in Table 1 and 2 are the same. Table 1 shows the evaluation results of the elastic modulus at 230 ° C., the number of occurrences of short-circuit failure, and the adhesion strength of these resins.
[0029]
[Table 2]

[0030]
If the elastic modulus at 230 ° C. is small, the volume expansion of the molten solder can be sufficiently absorbed, so that short-circuit failure due to solder flow does not occur. However, when the elastic modulus is too small, the adhesion strength with the surface acoustic wave element 2 is reduced. Accordingly, when a sample having a die shear strength of 40 N or more, which has no short-circuit failure and has a sufficient adhesion strength, is judged to be acceptable,

sample numbers

3, 4, 5, and 6 pass, that is, the elastic modulus at 230 ° C. is 0. What is necessary is just to select the resin which is 0.2 GPa to 0.8 GPa.
[0031]
Therefore, when the judgment in Table 1 and the judgment in Table 2 are combined, it is possible to use a resin having an elastic modulus at 25 ° C. of 3.5 GPa to 6 GPa and an elastic modulus at 230 ° C. of 0.2 GPa to 0.8 GPa. Then, the resins of

sample numbers

4, 5, and 6 can be used as resins satisfying both.
[0032]
In the above-described embodiment, an example of a surface acoustic wave device using a surface acoustic wave element as an electronic component element has been described. However, regardless of the type of the electronic component element, the electronic component element uses a solder pump and a solder joint member. Needless to say, the present invention can be widely applied to an electronic component device connected to a base substrate and covered on its side surface with an exterior member.
[0033]
For example, FIG. 4 is a cross-sectional view schematically showing an example in which the present invention is applied to a piezoelectric device using a piezoelectric resonance element instead of a surface acoustic wave element.
[0034]
In the figure, a piezoelectric device 700 includes a piezoelectric element 7, a base substrate 3, a solder bump member 4, a solder bonding member 5, and an exterior member 6, and the configuration other than the piezoelectric element 7 is the surface acoustic wave shown in FIG. It is exactly the same as the device 1.
[0035]
The piezoelectric element 7 can be exemplified by a piezoelectric resonator, a filter combining a plurality of piezoelectric resonators, a duplexer, or the like. For example, a piezoelectric layer 71 made of aluminum nitride is provided on one main surface of a substrate 70 made of silicon. Are formed, and a pair of vibration electrodes 72 and connection electrodes 8 respectively connected to the vibration electrodes 72 are formed. Further, an annular outer peripheral sealing electrode 9 for hermetically sealing a gap formed between the piezoelectric element 7 and the base substrate 3 is formed on the outer periphery of one main surface of the base 70. A gap 73 is formed on the vibration area of the vibration electrode 72 to prevent the vibration from attenuating.
[0036]
Further, the vibration electrode 72 is formed with a surface layer made of molybdenum, tungsten, aluminum, or the like, and the connection electrode 8 and the outer peripheral sealing electrode 9 are formed with a surface layer made of a chromium layer, a nickel layer, a gold layer, or the like as necessary. Good connection with solder.
[0037]
With the above-described configuration, the piezoelectric element 7 operates as a resonator using the vibration in the thickness direction of the piezoelectric layer 71 or as a filter or a duplexer in which a plurality of the resonators are combined. Also in the device, a small and highly reliable piezoelectric device can be configured.
[0038]
【The invention's effect】
According to the electronic component device of the present invention, the side surface exterior member attached to the side surface of the electronic component element and the outer peripheral surface of the solder joint member is formed between the surface of the base substrate due to volume expansion when the solder bump member and the solder joint member melt. It has an elastic modulus that follows a change in the distance between the component element and one main surface. Therefore, when mounting the electronic component device on the motherboard, when the solder bump member and the solder bonding member are melted by heat such as solder reflow and the volume expansion occurs, the volume expansion is not hindered. There is no danger of short-circuiting.
[Brief description of the drawings]
FIG. 1 is a sectional view of an electronic component device of the present invention.
FIG. 2 is a plan view of a base substrate used in the electronic component device of the present invention.
3A and 3B are cross-sectional views of the electronic component device of the present invention, in which FIG. 3A is a cross-sectional view of a solder bump member and a solder bonding member when they are solidified, and FIG. FIG.
FIG. 4 is a cross-sectional view schematically illustrating a structure of a piezoelectric device to which the present invention is applied.
FIG. 5 is a sectional view of a conventional electronic component device.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Surface acoustic wave device 2 ... Surface acoustic wave element 3 ... Base substrate 4 ... Solder bump member 5 ... Solder joining member 6 ... Exterior member 6a ... Top exterior member 6b ..Side exterior member 7 ... Piezoelectric element 8 ... Connection electrode 9 ... Outer periphery sealing electrode 10 ... Element connection electrode 11 ... Outer periphery sealing conductor film

Claims

On the other hand, an electronic component element having a connection electrode and an outer peripheral sealing electrode formed on a main surface,
An element connection electrode connected to the connection electrode via a solder bump member, an outer peripheral sealing conductor film joined to the outer peripheral sealing electrode via a solder joining member, and a base substrate on which an external terminal electrode is formed, Along with joining such that a predetermined space is formed between the base substrate and the electronic component element,
An electronic component device comprising: a side surface exterior member on the side surface of the electronic component element and an outer peripheral surface of the solder bonding member; and an upper surface exterior member on the other main surface of the electronic component element.
The side exterior member has an elasticity that follows a change in the distance between the base substrate and the electronic component element caused by volume expansion of the solder bump member and the solder joint member at a melting temperature of the solder bump member and the solder joint member. An electronic component device having a rate.

The electronic component device according to claim 1, wherein the side surface exterior member is a resin having thermoreversibility.

The elastic modulus of the side exterior member at a temperature of 25 ° C is 3.5 GPa to 6 GPa, and the elastic modulus at a temperature of 230 ° C is 0.2 GPa to 0.8 GPa. Electronic component device according to the above.