JP2005045414A - Surface acoustic wave device - Google Patents

Surface acoustic wave device Download PDF

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Publication number
JP2005045414A
JP2005045414A JP2003201348A JP2003201348A JP2005045414A JP 2005045414 A JP2005045414 A JP 2005045414A JP 2003201348 A JP2003201348 A JP 2003201348A JP 2003201348 A JP2003201348 A JP 2003201348A JP 2005045414 A JP2005045414 A JP 2005045414A
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Prior art keywords
bonding
adhesive
acoustic wave
surface acoustic
wire
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JP2003201348A
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Japanese (ja)
Inventor
Shuichi Iguchi
修一 井口
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Seiko Epson Corp
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Seiko Epson Corp
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Priority to JP2003201348A priority Critical patent/JP2005045414A/en
Publication of JP2005045414A publication Critical patent/JP2005045414A/en
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    • H01L2924/351—Thermal stress

Abstract

<P>PROBLEM TO BE SOLVED: To realize a stable operation, frequency characteristics, a high quality and high reliability by wire-bonding a SAW element always in an excellent joining state with sufficient joining strength in a SAW device for high frequencies with high precision. <P>SOLUTION: The SAW element 5 is supported with bonding wires 7 and 8 which are the suspension wires without contacting a base 1 or bonded and fixed to the base with an adhesive 16 whose elasticity modulus is small. Join parts between a bonding pad 11 and a ground electrode 12 of the SAW element, and bonding wires are completely covered with a conductive adhesive 15 whose elasticity modulus is small. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

【０００１】
【発明の属する技術分野】
本発明は、弾性表面波（ＳＡＷ：ｓｕｒｆａｃｅ ａｃｏｕｓｔｉｃ ｗａｖｅ ）素子をパッケ−ジ内に気密封止した弾性表面波（ＳＡＷ）デバイスに関し、特にＳＡＷ素子をワイヤボンディングで接続するＳＡＷデバイスの構造に関する。
【０００２】
【従来の技術】
従来から、圧電基板の表面に形成した交差指電極からなるＩＤＴ（すだれ状トランスデューサ）と反射器とを備え、ＩＤＴから励振した弾性表面波を利用するＳＡＷ素子を用いた共振子、フィルタ、発振器等のＳＡＷデバイスが様々な電子機器に広く使用されている。特に最近は、通信機器などの分野で、通信の高速化に対応したＳＡＷデバイスの高周波化及び高精度化が要求されている。
【０００３】
一般にＳＡＷデバイスは、セラミック材料からなるベースに金属リッドをシーム溶接で接合したパッケージの中にＳＡＷ素子を気密封止する。ＳＡＷ素子は、圧電基板表面に形成したＩＤＴのボンディングパッドをパッケージ側の接続端子とボンディングワイヤで電気的に接続する。ＳＡＷ素子の場合、ＩＤＴなどの電極膜は、その質量、膜厚、パターニングの容易性、コストなどを考慮して、アルミニウムで形成するのが一般的である。
【０００４】
接合界面における金属材料の共晶を避けるために、アルミニウムのボンディングパッドに対してアルミニウム系材料のボンディングワイヤを使用し、ウエッジボンディング法により、その先端部をボンディングパッド面にウエッジツールで加圧しつつ超音波振動を加えて接合する（例えば、特許文献１を参照）。また、ボンディングワイヤに金線を使用し、ボールボンディング法により、その先端を加熱溶融させて形成したボールを圧着して接合することもできる。
【０００５】
ＳＡＷ素子は、通常その下面を接着剤でベースの実装面に接着固定する。しかし、シーム溶接の際に、熱膨張率の大きい金属製リッドが封止後に冷却収縮して、ベースを変形させるような応力が発生するため、これが接着剤を介してＳＡＷ素子に伝達され、その周波数特性を変化させる虞がある。また、接着剤が硬化する際に幾分収縮するため、それによる応力がＳＡＷ素子に作用して悪影響を及ぼす虞がある。更に、外部から落下などによる衝撃がＳＡＷデバイスに加わることによって、周波数特性が変動する場合がある。
【０００６】
これらの応力は、特にＳＡＷデバイスの高周波化及び高精度化には好ましくないことから、パッケージのキャビティ底面にシリコン樹脂層を形成しかつその上にシリコン樹脂系の弾性接着剤を用いてＳＡＷ素子を接着固定し、シーム溶接による熱変形などの応力や衝撃を吸収する構造が提案されている（特許文献２を参照）。また、本願出願人は、ＳＡＷ素子をパッケージ基板に対してボンディングワイヤからなる吊り線により非接触で支持することにより、熱などの応力や衝撃による周波数の変化を防止して、安定した周波数特性が得られるようにしたＳＡＷデバイスを提案している（特許文献３を参照）。
【０００７】
また、ＩＤＴのボンディングパッドとボンディングワイヤとの接合状態が不十分で、接合強度が低いと、落下の衝撃などによって接合部が破断したり、接合部における電気抵抗が増大し、安定して所望の性能を得られない虞がある。ボンディングワイヤの接合強度を増大させるために、従来から半導体装置の分野では、ステッチボンディンクグによる接合部の上にボールボンディングを追加し、また更にその上から加圧及び超音波振動を加えてステッチボンディングしたり、接合部上面に導電性接着剤や金属を塗布して補強する手法が知られている（例えば、特許文献３乃至６を参照）。
【０００８】
【特許文献１】特開２００３−１１０４０１号公報
【特許文献２】特開２００２−１６４７６号公報
【特許文献３】特開２０００−１６５１９０号公報
【特許文献４】特開平５−１３４９１号公報
【特許文献５】特開２０００−１０１４７号公報
【特許文献６】特開２００２−３２９７４０号公報
【０００９】
【発明が解決しようとする課題】
ＳＡＷデバイスの高周波化及び高精度化に対応するためにＳＡＷ素子を弾性接着剤で接着固定する場合、弾性接着剤には、その硬化後にシーム溶接による熱応力や接着剤の硬化収縮による応力を十分に吸収し得る柔らかさ、即ち小さい弾性率が要求されるから、ボンディングワイヤ先端部をウエッジツールでボンディングパッド面に押圧したとき、接着剤が変形してＳＡＷ素子が大きく沈み込む虞がある。ウエッジボンディング法では、ボンディングワイヤの接合状態が超音波の出力、ボンディングワイヤへの荷重、処理時間、及びこれらのバランスにより左右されるから、ＳＡＷ素子の沈み込みが大き過ぎると、ボンディングワイヤへの荷重及び超音波振動が逃げてしまい、良好な接合状態が得られない。また、ＳＡＷ素子をパッケージ基板にボンディングワイヤからなる吊り線で非接触に支持するＳＡＷデバイスにおいても、ワイヤボンディング時にＳＡＷ素子が下面側から十分に支持されない虞があり、同様に良好な接合状態が得られないという問題が生じる。
【００１０】
更に、ＳＡＷ素子の表面に形成されるＩＤＴなどの電極膜は、高周波化を進めるとそれだけ膜厚が薄くなる。ＩＤＴのボンディングパッドとボンディングワイヤとが正常に接合された場合でも、ボンディングパッドの膜厚が薄くなるほど、その接合強度（公知のプルテストにおけるプル強度）は低下する。例えば図５は、市販の自動超音波ウエッジボンダを使用し、加工時間２０ｍｓ、超音波出力１５０Ｗ、加圧力５０ｇの条件で４０μｍ径のＡｌ／Ｓｉ１％ワイヤを接合した場合におけるボンディングパッド（電極）の膜厚（Å）とプル強度（ｇ）との関係を示している。また、ボンディングパッドの膜厚が薄いと、ボンディングワイヤとの接合状態は不十分になり易く、接合強度を低下させる可能性が高くなる。
【００１１】
また、金線を用いたボールボンディングでは、上述したように接合界面における異種金属材料の共晶の問題があり、ボンディングパッドの膜厚が薄くなると、リッドのシーム溶接などによる熱で共晶が過度に進行した場合、接合強度が低下する。
【００１２】
これに対し、上記特許文献３乃至６に記載されるワイヤボンディングの接合補強方法において、アルミニウムのボンディングパッドに金線で追加のボールボンディングをする場合、接合界面における金属の共晶の問題を解消することはできない。更に、同質材料のワイヤで追加のボールボンディングをする場合であっても、その分だけＳＡＷ素子表面における質量が増加するので、その振動、周波数特性に影響を及ぼす虞がある。また、特許文献５記載のように、追加のボールボンディングに更に加圧及び超音波振動を加えても、ＳＡＷ素子が弾性接着剤で固定されたり吊り線で支持される場合、荷重及び超音波振動が逃げるので、良好な接合状態は期待できない。従って、これら従来の接合補強方法をそのままＳＡＷ素子のワイヤボンディングに適用することはできない。
【００１３】
そこで本発明は、上述した従来の問題点に鑑みてなされたものであり、その目的は、特にＳＡＷデバイスの高周波化及び高精度化に対応して、ＳＡＷ素子を弾性率の小さい接着剤で接着したり吊り線で非接触に支持する構造においても、常に十分な接合強度、良好な接合状態でＳＡＷ素子をワイヤボンディングすることができ、安定した動作及び周波数特性を実現する高品質・高信頼性のＳＡＷデバイスを提供することにある。
【００１４】
【課題を解決するための手段】
本発明によれば、上記目的を達成するために、圧電基板上にＩＤＴ及び反射器を形成したＳＡＷ素子と、該ＳＡＷ素子を気密封止するパッケージとを備え、ＳＡＷ素子上面のボンディングパッドとパッケージの接続端子とがボンディングワイヤで接続され、該ボンディングパッドとボンディングワイヤとの接合部が接着剤で完全に被包されていることを特徴とするＳＡＷデバイスが提供される。
【００１５】
このように、ボンディングパッドとボンディングワイヤとの接合部を接着剤で補強することにより、ＳＡＷ素子の振動、周波数特性に影響を与えることなく、接合強度を増大させることができる。従って、常に安定した動作及び周波数特性を実現することができ、高品質・高信頼性のＳＡＷデバイスを歩留まり良く提供でき、かつ製造コストを低減することができる。
【００１６】
或る実施例では、前記接着剤が導電性接着剤であり、それにより接合強度の増大に加えて、接合部における導通性が向上し、ＳＡＷデバイスの良好かつ安定した動作を確保することができる。
【００１７】
別の実施例では、前記接着剤が低弾性率の接着剤であり、該接着剤の硬化時にその収縮による応力の発生を少なくして、接合部及び接合後のボンディングワイヤに及ぼす影響を最小限に抑制することができる。
【００１８】
また、或る実施例では、ボンディングワイヤが従来と同様にウエッジボンディングによりボンディングパッドに接合され、又はボールボンディングにより接合されるが、いずれの場合にも十分な接合強度を確保でき、かつ従来のボンディング方法及び設備をそのまま利用できるので、追加の処理及びコストを最小限に抑えることができ、好都合である。ここで、ウエッジボンディングによる場合、ボンディングパッド及びボンディングワイヤがアルミニウム系材料であると、共晶の問題もなく、加工性が良くかつ低コストであることから好ましい。
【００１９】
本発明は、ＳＡＷ素子の実装構造に拘わらず適用することができ、常に良好な接合状態、十分な接合強度を確保することができる。特に、ＳＡＷ素子がその下面を、例えば低弾性率の接着剤でパッケージの実装面に接着固定される場合、又はボンディングワイヤでパッケージ内に非接触で支持される場合に、ワイヤボンディング時にＳＡＷ素子の下面がしっかりと支持されないために接合状態が不十分になる虞を解消できる。従って、熱などの応力や衝撃による周波数の変化を防止して、高周波化及び高精度化に対応したＳＡＷデバイスが実現される。
【００２０】
また、或る実施例では、ボンディングパッドとボンディングワイヤとの接合部を被包する接着剤と、ＳＡＷ素子を固定する接着剤とが同一のものであると、両方の接着剤を同一条件で硬化させることができる。更に、接着剤から発生するガスがパッケージ内に残存してＳＡＷ素子の周波数を変化させるなどの悪影響を及ぼす虞を予め解消するために、パッケージの封止前に接着剤を硬化させる真空ベークの条件を揃えることができ、好都合である。
【００２１】
【発明の実施の形態】
以下に、本発明によるＳＡＷデバイスの好適実施例について添付図面を参照しつつ詳細に説明する。
【００２２】
図１（Ａ）、（Ｂ）は、本発明を適用したＳＡＷ共振子の第１実施例の構成を示している。このＳＡＷ共振子は、上部を開放した矩形箱状のべース１の上端に金属薄板のリッド２を、シールリング３を介してシーム溶接により気密に接合したパッケージ４を有し、その中にＳＡＷ素子５が封止されている。べース１は、アルミナ等セラミック材料からなる複数の薄板を積層して構成され、その内部に画定される空所６内にＳＡＷ素子５がボンディングワイヤ７、８を吊り線として、べース１に非接触の状態で支持されている。
【００２３】
ＳＡＷ素子５は、水晶、リチウムタンタレート、リチウムニオベートなどの圧電材料からなる矩形基板の上面中央に１対の交差指電極９、９からなるＩＤＴが形成され、その長手方向両側に格子状の反射器１０、１０が形成されている。各交差指電極９、９には、そのバスバーに連続して前記基板の長手方向辺縁近傍にボンディングパッド１１、１１がそれぞれ形成されている。前記基板上面の各隅部付近には、それぞれ接地電極１２が形成されている。本実施例の交差指電極、反射器、ボンディングパッド及び接地電極は、加工性及びコストの観点からアルミニウムで形成されているが、それ以外の一般に使用されているアルミニウム合金などの導電性金属材料を使用することができる。
【００２４】
べース１内部には、ＳＡＷ素子５の幅方向の両側に段差が設けられ、その上面には中央に信号入出力用の接続端子１３、１３と、その両側に接地端子１４とがそれぞれ形成されている。対応するボンディングパッド１１、１１と接続端子１３、１３とがループ状に形成されたボンディングワイヤ７、７で電気的に接続され、かつ、各接地電極１２と隣接する接地端子１４とがそれぞれ同様にループ状のボンディングワイヤ８で電気的に接続されている。
【００２５】
本実施例のボンディングワイヤには、共晶による接合強度の低下を防止するために、前記ボンディングパッドと同じ導電材料のアルミニウム線を使用する。前記接続端子及び接地端子は、例えばＷ、Ｍｏ等の金属配線材料をべース１のセラミック薄板の表面にスクリーン印刷しかつその上にＮｉ、Ａｕをめっきすることにより形成され、前記セラミック薄板に設けた配線パターンやビアホール（図示せず）を介して、べース１外面の外部端子に接続されている。
【００２６】
各ボンディングワイヤ７、８は、第１ボンドとしてパッケージ側の接続端子１３及び接地端子１４に一方の端部を例えばボールボンディングで接続する。次に、第２ボンドとして各ボンディングワイヤ７、８の他方の端部を対応するボンディングパッド１１及び接地電極１２に、ウエッジツールの下端で所定の荷重で加圧しかつ超音波振動を加えてウエッジボンディング法により接続する。ボンディングパッド及び接地電極とボンディングワイヤ７、８の先端部とは、予めその表面を機械的に清浄化して酸化膜を除去しておくことが望ましい。
【００２７】
ウエッジボンディングの際、ＳＡＷ素子５は、例えば上記特許文献３に記載されるように、その下面を適当な支持ツールを用いて、又はベースの空所底面に固定した弾性体や紫外線照射により接着力を失う接着シートにより、ベースの空所底面から浮かせた状態に支持する。そのため、ＳＡＷ素子５の下面が十分に支持されず、ウエッジツールの加圧及び超音波振動が逃げて、良好な接合状態が得られない虞がある。
【００２８】
ボンディングワイヤ７、８とボンディングパッド１１及び接地電極１２との接合部は、図２（Ａ）、（Ｂ）に示すように、接着剤１５で完全に被包する。これにより接合部が補強されるので、ワイヤボンディングによる接合状態が不良又は不十分な場合でも、常に十分な接合強度を確保することができる。
【００２９】
接着剤１５は、その硬化時の収縮による応力の発生を少なくして、接合部及び接合後のボンディングワイヤに与える影響を最小に抑制するために、例えばシリコン系樹脂のような低弾性率の接着剤が好ましい。また、接着剤１６が導電性接着剤であると、接合強度の増大に加えて、接合部における導通性が向上し、ＳＡＷ共振子の良好かつ安定した動作を確保することができる。このような導電性接着剤として、従来から公知のシリコン系、ポリブタジエン系、ウレタン系又はエボキシ系のものを使用することができる。
【００３０】
接着剤１５の塗布は、例えば市販のディスペンサを用いて又は人手により行う。また、必要最少量の接着剤を前記接合部に正確に塗布するためには、画像認識装置付きのダイボンダを使用することが望ましい。
【００３１】
このようにしてＳＡＷ素子５を実装しかつ結線した後、シーム溶接でリッド２をべース１上端にシールリング３に接合して、パッケージ１４を気密に封止する。本実施例のＳＡＷ共振子は、ＳＡＷ素子５がボンディングワイヤ７、８でベース１と非接触で支持され、かつボンディングワイヤとの接合部が接着剤１５で補強されているので、熱変形などの応力や衝撃による周波数の変化を防止して、高周波化及び高精度化を図ると同時に、高品質及び高信頼性を実現できる。
【００３２】
図３は、図１に示すＳＡＷ共振子の変形例を示している。この変形例では、ＳＡＷ素子５が、その下面を弾性接着剤１６でベース１の空所６底面に接着固定されている。図１の実施例と同様に、ＳＡＷ素子５のボンディングパッド１１、１１とベース１の接続端子１３、１３とはボンディングワイヤ７、７で電気的に接続され、かつそれらの接合部は接着剤１５により補強されている。
【００３３】
ＳＡＷ共振子の高周波化及び高精度化に対応するために、弾性接着剤１６に硬化後の弾性率が０．１Ｇｐａ以下の柔らかいシリコン樹脂系接着剤を使用することによって、シーム溶接による熱応力や接着剤の硬化収縮による応力及び外部からの衝撃を有効に吸収することができる。その場合、ボンディングワイヤ７、７をウエッジボンディングする際に、ＳＡＷ素子５がウエッジツールの加圧で大きく沈み込み、良好な接合状態が得られない虞がある。しかし、ボンディングパッドとボンディングワイヤとの接合部が接着剤１５で補強されているので、ワイヤボンディングによる接合状態が不良又は不十分な場合でも、常に十分な接合強度が確保される。
【００３４】
この実施例において、ボンディングパッド１１とボンディングワイヤ７との接合部を被包する接着剤１５と、ＳＡＷ素子５を固定する接着剤１６とが同一のものであると、両接着剤を同一条件で硬化させることができる。このとき、接着剤から発生するガスがパッケージ内に残存してＳＡＷ素子の周波数を腐食させないように、パッケージ４の封止前に真空ベークで接着剤１５、１６を硬化させるが、その条件を統一することができるので、好ましい。
【００３５】
図４（Ａ）、（Ｂ）は、本発明によるＳＡＷ共振子の第２実施例の要部を示している。第２実施例では、ＳＡＷ素子５のボンディングパッド１１とベース１の接続端子１３とを接続するボンディングワイヤ１７が金線であり、かつその先端を適当な加熱手段で溶融させることにより形成したボール１８を圧着させるボールボンディングで接合されている点で、上記各実施例と異なる。
【００３６】
この実施例においても、ボンディングパッド１１とボンディングワイヤ１７との接合部は、同様に接着剤１５で完全に被包されて補強されている。ボンディングパッド１１がアルミニウムで形成されているので、接合界面には共晶の問題が生じる。特にボンディングパッドの膜厚が薄くなると、リッドのシーム溶接などによる熱で共晶が過度に進行した場合に接合強度が低下するが、接合部が接着剤１５で補強されているので、常に十分な接合強度を維持することができる。
【００３７】
ＳＡＷ素子５は、図１のようにボンディングワイヤを吊り線としてベースに非接触で支持する構造でも、図２のように弾性接着剤でベースに接着固定する構造でもよい。いずれの場合にも、接合界面における金属材料の共晶による接合強度の低下を、接着剤１５による接合部の補強で十分に補うことができる。従って、熱変形などの応力や衝撃による周波数の変化を防止して、ＳＡＷ共振子の高周波化及び高精度化と共に、その高品質及び高信頼性を達成することができる。
【００３８】
また、本発明は上記実施例に限定されるものではなく、これに様々な変形・変更を加えて実施し得ることは当業者に明らかである。例えば、ＳＡＷ素子を用いたフィルタ、発振器等のＳＡＷデバイスについても、同様に適用することができる。
【００３９】
【実施例】
（実施例１）
上述した本発明の第１実施例の吊り線によるＳＡＷ素子の支持構造を有するＳＡＷ共振子を製造した。ボンディングワイヤは４０μｍ径のＡｌ／Ｓｉ１％ワイヤを使用し、市販の自動超音波ウエッジボンダを用いて、加工時間２０ｍｓ、超音波出力１５０Ｗ、加圧力５０ｇの条件でウエッジボンディングした。接合部は、弾性率０．０５Ｇｐａのシリコン系低弾性率導電性接着剤で完全に被包し、補強した。比較例として、本実施例と同様の構造を有するが、接合部を接着剤で補強しないＳＡＷ共振子を製造した。
【００４０】
これらのＳＡＷ共振子に、−５５℃３０分、１２５℃３０分の低温高温繰り返しによる耐久性試験を行い、ボンディングワイヤの接合はがれをＳＡＷ共振子の発振不良として検出し、接合状態の信頼性を試験した。その結果を次の表１に示す。本実施例のＳＡＷ共振子は、低温高温繰り返しを５００サイクル行った場合でも、発振不良が発生しなかった。これに対し、比較例では、低温高温繰り返しが多くなるほど、発振不良が多く発生した。
【００４１】
【表１】

Figure 2005045414
【００４２】
また、これらのＳＡＷ共振子を、１５０ｃｍの高さからコンクリート床面に繰り返し自然落下させる衝撃耐久性試験を行い、同様にボンディングワイヤの接合はがれをＳＡＷ共振子の発振不良として検出し、接合状態の信頼性を試験した。その結果を次の表２に示す。本実施例のＳＡＷ共振子は、１００回落下させた場合でも、発振不良が発生しなかった。これに対し、比較例では、落下回数が多くなるほど、発振不良が多く発生した。
【００４３】
【表２】
Figure 2005045414
【００４４】
これらの試験結果から、本実施例のワイヤボンディングの接合部を弾性接着剤で補強する構成によって、その接合強度が増大し、温度変化によるパッケージの変形応力及び外部からの衝撃に対して、高い信頼性を発揮し得ることが分かる。
【００４５】
（実施例２）
上述した本発明の第２実施例のＳＡＷ共振子を製造した。ボンディングワイヤは２５μｍ径のＡｕワイヤを使用し、市販のＡｕボールボンダを用いて、加工時間５ｍｓ、超音波出力７０Ｗ、加圧力４０ｇの条件で、膜厚２０００Åのアルミニウムで形成したボンディングパッドに圧着した。接合部は、弾性率０．０５Ｇｐａのシリコン系低弾性率導電性接着剤で完全に被包し、補強した。ＳＡＷ素子は弾性接着剤でベースに接着固定した。比較例として、本実施例と同様の構造を有するが、接合部を接着剤で補強しないＳＡＷ共振子を製造した。
【００４６】
これらのＳＡＷ共振子について、１２５℃１００時間放置する前後でボンディングワイヤのプルテストを行い、プル強度及び破壊モードを測定した。破壊モードは、ワイヤの破壊個所によって、ＳＡＷ素子ボンディングパッドとの界面剥離をＡ、ＳＡＷ素子ボンディングパッドとの接合部直近での切断をＢ、ワイヤの引張位置での切断をＣ、パッケージ接合端子との接合部直近での切断をＤ、パッケージ接合端子との界面剥離をＥで表す。この結果を以下の表３及び表４にそれぞれに示す。
【００４７】
【表３】
Figure 2005045414
【００４８】
【表４】
Figure 2005045414
【００４９】
本実施例では、１２５℃の高温に放置する前の初期値において高いプル強度を示すと共に、高温放置後も高いプル強度を維持した。また、破壊モードは高温放置の前後においてＣであった。これに対し、比較例は、高温放置前の初期値においてプル強度が本実施例の約半分であり、高温放置後は、更にその１／１０程度まで低下した。また、破壊モードは高温放置前の初期値においてＢであり、高温放置後はＡとなった。これから、本実施例を採用することによって、接合界面における金属材料の共晶が進行しても、十分な接合強度を維持し得ることが分かる。
【図面の簡単な説明】
【図１】（Ａ）図は本発明によるＳＡＷ共振子の第１実施例を示す平面図、（Ｂ）図はそのＩ−Ｉ線における断面図。
【図２】（Ａ）図はボンディングパッドとボンディングワイヤとの接合部を部分的に拡大して示す平面図、（Ｂ）図はその断面図。
【図３】図１の第１実施例の変形例を示す図１（Ｂ）と同様の断面図。
【図４】本発明によるＳＡＷ共振子の第２実施例の要部を示す図１（Ａ）と同様の部分拡大側面図。
【図５】ボンディングパッドの膜厚とプル強度との関係を例示する線図。
【符号の説明】
１…ベース、２…リッド、３…シールリング、４…パッケージ、５…ＳＡＷ素子、６…空所、７，８，１７…ボンディングワイヤ、９…交差指電極、１０…反射器、１１…ボンディングパッド、１２…接地電極、１３…接続端子、１４…接地端子、１５，１６…接着剤、１０，２４…ウエッジツール、１６…実装面、１７…弾性接着剤、１８…ボール。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a surface acoustic wave (SAW) device in which a surface acoustic wave (SAW) element is hermetically sealed in a package, and more particularly to a structure of a SAW device in which SAW elements are connected by wire bonding.
[0002]
[Prior art]
Conventionally, a resonator, a filter, an oscillator, etc. using a SAW element having an IDT (interdigital transducer) made of interdigitated electrodes formed on the surface of a piezoelectric substrate and a reflector and using a surface acoustic wave excited from the IDT SAW devices are widely used in various electronic devices. In particular, in recent years, in the field of communication equipment and the like, there has been a demand for higher frequency and higher accuracy of SAW devices corresponding to higher communication speeds.
[0003]
In general, a SAW device hermetically seals a SAW element in a package in which a metal lid is joined to a base made of a ceramic material by seam welding. In the SAW element, an IDT bonding pad formed on the surface of the piezoelectric substrate is electrically connected to a connection terminal on the package side by a bonding wire. In the case of a SAW element, an electrode film such as IDT is generally formed of aluminum in consideration of its mass, film thickness, ease of patterning, cost, and the like.
[0004]
In order to avoid eutectic of the metal material at the bonding interface, an aluminum-based material bonding wire is used for the aluminum bonding pad, and the tip of the bonding pad surface is pressed against the bonding pad surface with a wedge tool by the wedge bonding method. Joining by applying sonic vibration (see, for example, Patent Document 1). Further, a gold wire can be used as a bonding wire, and a ball formed by heating and melting the tip can be bonded by a ball bonding method.
[0005]
SAW elements usually have their lower surfaces bonded and fixed to the base mounting surface with an adhesive. However, during seam welding, a metal lid having a high thermal expansion coefficient is cooled and contracted after sealing, and stress that deforms the base is generated. This is transmitted to the SAW element via the adhesive, and the There is a risk of changing the frequency characteristics. Further, since the adhesive shrinks somewhat when it is cured, there is a risk that the resulting stress acts on the SAW element and adversely affects it. Furthermore, the frequency characteristics may fluctuate due to external shock applied to the SAW device.
[0006]
Since these stresses are not particularly preferable for increasing the frequency and accuracy of SAW devices, a silicon resin layer is formed on the bottom surface of the cavity of the package, and a SAW element is formed using a silicon resin-based elastic adhesive thereon. There has been proposed a structure that adheres and fixes and absorbs stress and impact such as thermal deformation caused by seam welding (see Patent Document 2). In addition, the applicant of the present application supports the SAW element in a non-contact manner with a hanging wire made of a bonding wire to the package substrate, thereby preventing a change in frequency due to stress such as heat or a shock, and providing a stable frequency characteristic. A SAW device that can be obtained has been proposed (see Patent Document 3).
[0007]
Also, if the bonding state between the IDT bonding pad and the bonding wire is insufficient and the bonding strength is low, the bonded portion breaks due to a drop impact or the like, the electrical resistance at the bonded portion increases, and the desired state is stably obtained. There is a possibility that performance cannot be obtained. In order to increase the bonding strength of bonding wires, in the field of semiconductor devices, ball bonding has been added on the joints by stitch bonding, and pressure and ultrasonic vibration are further applied from above to the stitches. There are known methods for bonding or reinforcing a bonding adhesive by applying a conductive adhesive or metal on the upper surface of the joint (see, for example, Patent Documents 3 to 6).
[0008]
[Patent Document 1] JP 2003-110401 [Patent Document 2] JP 2002-16476 [Patent Document 3] JP 2000-165190 [Patent Document 4] JP 5-13491 [Patent Document 5 Japanese Patent Laid-Open No. 2000-10147 [Patent Document 6] Japanese Patent Laid-Open No. 2002-329740
[Problems to be solved by the invention]
When the SAW element is bonded and fixed with an elastic adhesive in order to cope with higher frequency and higher accuracy of the SAW device, the elastic adhesive is sufficiently subjected to thermal stress due to seam welding and stress due to curing shrinkage of the adhesive after curing. Therefore, when the tip of the bonding wire is pressed against the bonding pad surface with a wedge tool, the adhesive may be deformed and the SAW element may sink greatly. In the wedge bonding method, since the bonding state of the bonding wire depends on the output of the ultrasonic wave, the load on the bonding wire, the processing time, and the balance between them, if the SAW element sinks too much, the load on the bonding wire In addition, the ultrasonic vibration escapes and a good bonded state cannot be obtained. Further, even in a SAW device that supports a SAW element on a package substrate in a non-contact manner using a hanging wire made of a bonding wire, the SAW element may not be sufficiently supported from the lower surface side during wire bonding, and a good bonding state can be obtained similarly. The problem of not being able to occur.
[0010]
Furthermore, the electrode film such as IDT formed on the surface of the SAW element becomes thinner as the frequency increases. Even when the IDT bonding pad and the bonding wire are normally bonded, the bonding strength (pull strength in a known pull test) decreases as the thickness of the bonding pad decreases. For example, FIG. 5 shows a bonding pad (electrode) in a case where a commercially available automatic ultrasonic wedge bonder is used and a 40 μm diameter Al / Si 1% wire is bonded under the conditions of a processing time of 20 ms, an ultrasonic output of 150 W, and a pressing force of 50 g. The relationship between film thickness (Å) and pull strength (g) is shown. Moreover, when the film thickness of the bonding pad is thin, the bonding state with the bonding wire is likely to be insufficient, and the possibility of reducing the bonding strength increases.
[0011]
In addition, as described above, ball bonding using a gold wire has a problem of eutectic of dissimilar metal materials at the bonding interface. When the film thickness of the bonding pad is reduced, the eutectic is excessive due to heat from seam welding of the lid. When it progresses to, the joint strength decreases.
[0012]
On the other hand, in the bonding reinforcement method of wire bonding described in Patent Documents 3 to 6, when additional ball bonding is performed with an aluminum bonding pad using a gold wire, the problem of metal eutectic at the bonding interface is solved. It is not possible. Furthermore, even when additional ball bonding is performed with a wire made of a homogeneous material, the mass on the surface of the SAW element increases by that amount, which may affect the vibration and frequency characteristics. In addition, as described in Patent Document 5, when additional pressure bonding and ultrasonic vibration are applied to additional ball bonding, if the SAW element is fixed with an elastic adhesive or supported by a hanging line, the load and ultrasonic vibration Therefore, it is not possible to expect a good bonding state. Therefore, these conventional bonding reinforcement methods cannot be applied as they are to wire bonding of SAW elements.
[0013]
Accordingly, the present invention has been made in view of the above-described conventional problems, and its purpose is to bond a SAW element with an adhesive having a low elastic modulus, particularly in response to higher frequency and higher accuracy of a SAW device. High quality and high reliability to realize stable operation and frequency characteristics, even when the structure is supported in a non-contact manner by a hanging wire or a suspension line. To provide a SAW device.
[0014]
[Means for Solving the Problems]
According to the present invention, in order to achieve the above object, a SAW element in which an IDT and a reflector are formed on a piezoelectric substrate and a package for hermetically sealing the SAW element are provided, and a bonding pad and a package on the upper surface of the SAW element are provided. The connection terminal is connected with a bonding wire, and the bonding portion between the bonding pad and the bonding wire is completely encapsulated with an adhesive.
[0015]
Thus, by reinforcing the bonding portion between the bonding pad and the bonding wire with the adhesive, the bonding strength can be increased without affecting the vibration and frequency characteristics of the SAW element. Therefore, stable operation and frequency characteristics can be realized at all times, high-quality and high-reliability SAW devices can be provided with high yield, and manufacturing costs can be reduced.
[0016]
In one embodiment, the adhesive is a conductive adhesive, thereby improving the electrical conductivity at the joint in addition to increasing the joint strength and ensuring good and stable operation of the SAW device. .
[0017]
In another embodiment, the adhesive is a low-modulus adhesive, which reduces the occurrence of stress due to its shrinkage when the adhesive is cured, thereby minimizing the effect on the bonded portion and the bonded wire after bonding. Can be suppressed.
[0018]
In some embodiments, the bonding wire is bonded to the bonding pad by wedge bonding as in the prior art, or is bonded by ball bonding. In either case, sufficient bonding strength can be ensured, and conventional bonding can be achieved. Advantageously, the method and equipment can be used as is, which can minimize additional processing and costs. Here, in the case of wedge bonding, it is preferable that the bonding pad and the bonding wire are made of an aluminum-based material because there is no problem of eutectic and the workability is good and the cost is low.
[0019]
The present invention can be applied regardless of the mounting structure of the SAW element, and can always ensure a good bonding state and sufficient bonding strength. In particular, when the SAW element is bonded and fixed to the mounting surface of the package with an adhesive having a low elastic modulus, for example, or when it is supported in a non-contact manner in the package with a bonding wire, the SAW element is bonded during wire bonding. Since the lower surface is not firmly supported, the possibility that the bonding state becomes insufficient can be solved. Therefore, a change in frequency due to stress such as heat or shock is prevented, and a SAW device corresponding to higher frequency and higher accuracy is realized.
[0020]
In one embodiment, when the adhesive encapsulating the bonding portion between the bonding pad and the bonding wire is the same as the adhesive fixing the SAW element, both adhesives are cured under the same conditions. Can be made. Furthermore, in order to eliminate in advance the risk of adverse effects such as the gas generated from the adhesive remaining in the package and changing the frequency of the SAW element, conditions for vacuum baking for curing the adhesive before sealing the package It is convenient and can be arranged.
[0021]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, preferred embodiments of a SAW device according to the present invention will be described in detail with reference to the accompanying drawings.
[0022]
1A and 1B show the configuration of a first embodiment of a SAW resonator to which the present invention is applied. This SAW resonator has a package 4 in which a lid 2 made of a thin metal plate is airtightly joined to a top end of a rectangular box-like base 1 having an open upper portion by seam welding through a seal ring 3. The SAW element 5 is sealed. The base 1 is configured by laminating a plurality of thin plates made of a ceramic material such as alumina, and the SAW element 5 has a bonding wire 7 and 8 as suspension lines in a space 6 defined therein. 1 is supported in a non-contact state.
[0023]
The SAW element 5 has an IDT formed of a pair of crossed finger electrodes 9 and 9 formed at the center of the upper surface of a rectangular substrate made of a piezoelectric material such as quartz, lithium tantalate, or lithium niobate, and has a lattice shape on both sides in the longitudinal direction. Reflectors 10 and 10 are formed. Bonding pads 11 and 11 are formed on the cross finger electrodes 9 and 9 in the vicinity of the edge in the longitudinal direction of the substrate in succession to the bus bar. Ground electrodes 12 are formed in the vicinity of each corner on the upper surface of the substrate. The crossed finger electrode, reflector, bonding pad and ground electrode of the present embodiment are made of aluminum from the viewpoint of workability and cost, but other conductive metal materials such as aluminum alloys are generally used. Can be used.
[0024]
Steps are provided on both sides of the SAW element 5 in the width direction inside the base 1, and signal input / output connection terminals 13 and 13 are formed in the center on the upper surface, and ground terminals 14 are formed on both sides thereof. Has been. Corresponding bonding pads 11 and 11 and connection terminals 13 and 13 are electrically connected by bonding wires 7 and 7 formed in a loop shape, and each ground electrode 12 and adjacent ground terminal 14 are similarly connected. They are electrically connected by a looped bonding wire 8.
[0025]
The bonding wire of this embodiment uses an aluminum wire made of the same conductive material as that of the bonding pad in order to prevent a decrease in bonding strength due to eutectic. The connection terminal and the ground terminal are formed, for example, by screen-printing a metal wiring material such as W or Mo on the surface of the ceramic thin plate of the base 1 and plating Ni or Au on the surface of the ceramic thin plate. It is connected to an external terminal on the outer surface of the base 1 through a provided wiring pattern or via hole (not shown).
[0026]
Each of the bonding wires 7 and 8 is connected to the connection terminal 13 and the ground terminal 14 on the package side as a first bond, for example, by ball bonding. Next, as the second bond, the other end of each of the bonding wires 7 and 8 is pressed against the corresponding bonding pad 11 and the ground electrode 12 with a predetermined load at the lower end of the wedge tool and applied with ultrasonic vibration to perform wedge bonding. Connect by law. It is desirable that the bonding pad and ground electrode and the tips of the bonding wires 7 and 8 have their surfaces mechanically cleaned in advance to remove the oxide film.
[0027]
At the time of wedge bonding, the SAW element 5 is bonded to an elastic body with its lower surface fixed to the bottom surface of the base using an appropriate support tool or ultraviolet irradiation, as described in Patent Document 3, for example. It is supported by the adhesive sheet that loses the surface, in a state where it floats from the bottom surface of the void of the base. Therefore, the lower surface of the SAW element 5 is not sufficiently supported, and the pressurization and ultrasonic vibration of the wedge tool may escape and a good bonded state may not be obtained.
[0028]
The bonding portions between the bonding wires 7 and 8 and the bonding pads 11 and the ground electrode 12 are completely encapsulated with an adhesive 15 as shown in FIGS. As a result, the joint is reinforced, so that a sufficient joint strength can always be ensured even when the joint state by wire bonding is poor or insufficient.
[0029]
The adhesive 15 reduces the generation of stress due to shrinkage at the time of curing and minimizes the influence on the bonding portion and the bonding wire after bonding, for example, a low elastic modulus bonding such as a silicon-based resin. Agents are preferred. Further, when the adhesive 16 is a conductive adhesive, in addition to an increase in bonding strength, conductivity at the bonded portion is improved, and a good and stable operation of the SAW resonator can be ensured. As such a conductive adhesive, conventionally known silicon-based, polybutadiene-based, urethane-based, or epoxy-based adhesives can be used.
[0030]
Application of the adhesive 15 is performed using, for example, a commercially available dispenser or manually. In order to accurately apply the minimum amount of adhesive to the joint, it is desirable to use a die bonder with an image recognition device.
[0031]
After mounting and connecting the SAW element 5 in this manner, the lid 2 is joined to the seal ring 3 at the upper end of the base 1 by seam welding, and the package 14 is hermetically sealed. In the SAW resonator of this embodiment, the SAW element 5 is supported by the bonding wires 7 and 8 in a non-contact manner with the base 1 and the bonding portion with the bonding wire is reinforced by the adhesive 15. It is possible to prevent a change in frequency due to stress or impact, to achieve high frequency and high accuracy, and at the same time to realize high quality and high reliability.
[0032]
FIG. 3 shows a modification of the SAW resonator shown in FIG. In this modification, the SAW element 5 has its lower surface bonded and fixed to the bottom surface of the space 6 of the base 1 with an elastic adhesive 16. As in the embodiment of FIG. 1, the bonding pads 11, 11 of the SAW element 5 and the connection terminals 13, 13 of the base 1 are electrically connected by bonding wires 7, 7, and their joints are adhesive 15. It is reinforced by.
[0033]
In order to cope with higher frequency and higher accuracy of the SAW resonator, by using a soft silicone resin adhesive having an elastic modulus after curing of 0.1 Gpa or less as the elastic adhesive 16, thermal stress caused by seam welding can be reduced. Stress due to curing shrinkage of the adhesive and impact from the outside can be effectively absorbed. In this case, when the bonding wires 7 and 7 are wedge-bonded, the SAW element 5 may be greatly sunk by the pressure of the wedge tool, and a good bonding state may not be obtained. However, since the bonding portion between the bonding pad and the bonding wire is reinforced with the adhesive 15, sufficient bonding strength is always ensured even when the bonding state by wire bonding is poor or insufficient.
[0034]
In this embodiment, if the adhesive 15 encapsulating the bonding portion between the bonding pad 11 and the bonding wire 7 and the adhesive 16 for fixing the SAW element 5 are the same, both adhesives can be used under the same conditions. It can be cured. At this time, the adhesives 15 and 16 are cured by vacuum baking before sealing the package 4 so that the gas generated from the adhesive remains in the package and does not corrode the frequency of the SAW element. This is preferable.
[0035]
4A and 4B show the main part of a second embodiment of the SAW resonator according to the present invention. In the second embodiment, the bonding wire 17 that connects the bonding pad 11 of the SAW element 5 and the connection terminal 13 of the base 1 is a gold wire, and the ball 18 is formed by melting its tip with an appropriate heating means. They are different from the above embodiments in that they are joined by ball bonding for pressure bonding.
[0036]
Also in this embodiment, the joint between the bonding pad 11 and the bonding wire 17 is similarly completely encapsulated with the adhesive 15 and reinforced. Since the bonding pad 11 is made of aluminum, a eutectic problem occurs at the bonding interface. In particular, when the film thickness of the bonding pad is reduced, the bonding strength is reduced when the eutectic proceeds excessively due to heat such as seam welding of the lid. However, since the bonding portion is reinforced with the adhesive 15, it is always sufficient. Bonding strength can be maintained.
[0037]
The SAW element 5 may have a structure in which a bonding wire is supported as a suspension line in a non-contact manner as shown in FIG. 1 or a structure in which the SAW element 5 is bonded and fixed to the base with an elastic adhesive as shown in FIG. In any case, the decrease in the bonding strength due to the eutectic of the metal material at the bonding interface can be sufficiently compensated by the reinforcement of the bonded portion by the adhesive 15. Therefore, it is possible to prevent a change in frequency due to stress or impact such as thermal deformation, and to achieve high quality and high reliability as well as high frequency and high accuracy of the SAW resonator.
[0038]
The present invention is not limited to the above-described embodiments, and it will be apparent to those skilled in the art that various modifications and changes can be made thereto. For example, the present invention can be similarly applied to SAW devices such as filters and oscillators using SAW elements.
[0039]
【Example】
(Example 1)
A SAW resonator having a support structure for the SAW element by the suspension line of the first embodiment of the present invention described above was manufactured. The bonding wire was an Al / Si 1% wire with a diameter of 40 μm, and was subjected to wedge bonding using a commercially available automatic ultrasonic wedge bonder under the conditions of a processing time of 20 ms, an ultrasonic output of 150 W, and a pressing force of 50 g. The joint portion was completely encapsulated and reinforced with a silicon-based low elastic modulus conductive adhesive having an elastic modulus of 0.05 Gpa. As a comparative example, a SAW resonator having the same structure as that of the present example but not reinforced with a bonding portion was manufactured.
[0040]
These SAW resonators are subjected to durability tests at low temperatures and high temperatures of −55 ° C. for 30 minutes and 125 ° C. for 30 minutes to detect bonding wire bonding peeling as a SAW resonator oscillation failure and to improve the reliability of the bonding state. Tested. The results are shown in Table 1 below. In the SAW resonator of this example, no oscillation failure occurred even when 500 cycles of low temperature and high temperature repetition were performed. On the other hand, in the comparative example, as the number of low temperature and high temperature repetitions increased, more oscillation failures occurred.
[0041]
[Table 1]
Figure 2005045414
[0042]
In addition, an impact durability test in which these SAW resonators are repeatedly spontaneously dropped from a height of 150 cm onto a concrete floor surface is performed. Similarly, bonding wire peeling is detected as an oscillation failure of the SAW resonator, Reliability was tested. The results are shown in Table 2 below. Even when the SAW resonator of this example was dropped 100 times, no oscillation failure occurred. In contrast, in the comparative example, the greater the number of drops, the more oscillation failures occurred.
[0043]
[Table 2]
Figure 2005045414
[0044]
From these test results, the bonding strength of the wire bonding of this embodiment is reinforced with an elastic adhesive, and the bonding strength is increased, and high reliability against deformation stress of the package due to temperature change and external impact. It can be seen that it can exert its properties.
[0045]
(Example 2)
The SAW resonator according to the second embodiment of the present invention described above was manufactured. The bonding wire was an Au wire with a diameter of 25 μm, and was bonded to a bonding pad formed of aluminum having a thickness of 2000 mm using a commercially available Au ball bonder under conditions of a processing time of 5 ms, an ultrasonic output of 70 W, and a pressure of 40 g. . The joint portion was completely encapsulated and reinforced with a silicon-based low elastic modulus conductive adhesive having an elastic modulus of 0.05 Gpa. The SAW element was bonded and fixed to the base with an elastic adhesive. As a comparative example, a SAW resonator having the same structure as that of the present example but not reinforced with a bonding portion was manufactured.
[0046]
With respect to these SAW resonators, a pull test of the bonding wire was performed before and after leaving at 125 ° C. for 100 hours, and the pull strength and the fracture mode were measured. In the break mode, depending on the breakage point of the wire, the interface peeling with the SAW element bonding pad is A, the cutting near the joint with the SAW element bonding pad is B, the cutting at the tensile position of the wire is C, and the package bonding terminal In the figure, D indicates the cutting immediately before the bonding portion, and E indicates the interface peeling with the package bonding terminal. The results are shown in Table 3 and Table 4 below.
[0047]
[Table 3]
Figure 2005045414
[0048]
[Table 4]
Figure 2005045414
[0049]
In this example, a high pull strength was exhibited at an initial value before being left at a high temperature of 125 ° C., and a high pull strength was maintained even after being left at a high temperature. The failure mode was C before and after being left at high temperature. On the other hand, in the comparative example, the pull strength at the initial value before being left at high temperature was about half that of the present example, and after being left at high temperature, it was further reduced to about 1/10. Further, the fracture mode was B at the initial value before being left at high temperature, and was A after being left at high temperature. From this, it can be seen that by adopting this example, sufficient bonding strength can be maintained even if the eutectic of the metal material at the bonding interface proceeds.
[Brief description of the drawings]
FIG. 1A is a plan view showing a first embodiment of a SAW resonator according to the present invention, and FIG. 1B is a cross-sectional view taken along the line II of FIG.
2A is a plan view partially showing a bonding portion between a bonding pad and a bonding wire, and FIG. 2B is a cross-sectional view thereof.
3 is a cross-sectional view similar to FIG. 1B, showing a modification of the first embodiment of FIG.
FIG. 4 is a partially enlarged side view similar to FIG. 1 (A) showing an essential part of a second embodiment of a SAW resonator according to the present invention.
FIG. 5 is a diagram illustrating the relationship between the film thickness of the bonding pad and the pull strength.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Base, 2 ... Lid, 3 ... Seal ring, 4 ... Package, 5 ... SAW element, 6 ... Empty space, 7, 8, 17 ... Bonding wire, 9 ... Interstitial electrode, 10 ... Reflector, 11 ... Bonding Pad, 12 ... ground electrode, 13 ... connection terminal, 14 ... ground terminal, 15, 16 ... adhesive, 10, 24 ... wedge tool, 16 ... mounting surface, 17 ... elastic adhesive, 18 ... ball.

Claims (10)

圧電基板上にＩＤＴ及び反射器を形成した弾性表面波素子と、前記弾性表面波素子を気密封止するパッケージとを備え、前記弾性表面波素子上面のボンディングパッドと前記パッケージの接続端子とがボンディングワイヤで接続され、前記ボンディングパッドと前記ボンディングワイヤとの接合部が接着剤で完全に被包されていることを特徴とする弾性表面波デバイス。A surface acoustic wave element in which an IDT and a reflector are formed on a piezoelectric substrate and a package for hermetically sealing the surface acoustic wave element are provided, and a bonding pad on the surface of the surface acoustic wave element and a connection terminal of the package are bonded. A surface acoustic wave device, wherein the surface acoustic wave device is connected by a wire, and a joint between the bonding pad and the bonding wire is completely encapsulated with an adhesive. 前記接着剤が導電性接着剤であることを特徴とする請求項１に記載の弾性表面波デバイス。The surface acoustic wave device according to claim 1, wherein the adhesive is a conductive adhesive. 前記接着剤が低弾性率の接着剤であることを特徴とする請求項１に記載の弾性表面波デバイス。The surface acoustic wave device according to claim 1, wherein the adhesive is a low elastic modulus adhesive. 前記ボンディングワイヤが前記ボンディングパッドにウエッジボンディングで接合されていることを特徴とする請求項１乃至３のいずれに記載の弾性表面波デバイス。4. The surface acoustic wave device according to claim 1, wherein the bonding wire is bonded to the bonding pad by wedge bonding. 前記ボンディングパッド及び前記ボンディングワイヤがアルミニウム系材料からなることを特徴とする請求項４に記載の弾性表面波デバイス。The surface acoustic wave device according to claim 4, wherein the bonding pad and the bonding wire are made of an aluminum-based material. 前記ボンディングワイヤが前記ボンディングパッドにボールボンディングで接合されていることを特徴とする請求項１乃至３のいずれに記載の弾性表面波デバイス。4. The surface acoustic wave device according to claim 1, wherein the bonding wire is bonded to the bonding pad by ball bonding. 前記弾性表面波素子が、その下面を接着剤で前記パッケージの実装面に接着固定されていることを特徴とする請求項１乃至６のいずれに記載の弾性表面波デバイス。The surface acoustic wave device according to any one of claims 1 to 6, wherein the surface acoustic wave element has its lower surface bonded and fixed to the mounting surface of the package with an adhesive. 前記接着剤が低弾性率の接着剤であることを特徴とする請求項７に記載の弾性表面波デバイス。The surface acoustic wave device according to claim 7, wherein the adhesive is an adhesive having a low elastic modulus. 前記ボンディングパッドと前記ボンディングワイヤとの接合部を被包する前記接着剤と、前記弾性表面波素子を固定する前記接着剤とが同一のものであることを特徴とする請求項７又は８に記載の弾性表面波デバイス。9. The adhesive according to claim 7, wherein the adhesive encapsulating a bonding portion between the bonding pad and the bonding wire is the same as the adhesive fixing the surface acoustic wave element. Surface acoustic wave device. 前記弾性表面波素子が、前記ボンディングワイヤにより前記パッケージ内に非接触で支持されていることを特徴とする請求項１乃至６のいずれに記載の弾性表面波デバイス。The surface acoustic wave device according to any one of claims 1 to 6, wherein the surface acoustic wave element is supported in the package in a non-contact manner by the bonding wire.
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Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2007053130A (en) * 2005-08-15 2007-03-01 Matsushita Electric Ind Co Ltd Connection structure and connection method
JP2007220822A (en) * 2006-02-15 2007-08-30 Matsushita Electric Ind Co Ltd Connection structure and its fabrication process
JP2009206407A (en) * 2008-02-29 2009-09-10 Morioka Seiko Instruments Inc Wire bonding method
JP2013051582A (en) * 2011-08-31 2013-03-14 Kyocera Crystal Device Corp Package and piezoelectric device
JP2020088047A (en) * 2018-11-19 2020-06-04 新日本無線株式会社 Semiconductor device and manufacturing method thereof

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2007053130A (en) * 2005-08-15 2007-03-01 Matsushita Electric Ind Co Ltd Connection structure and connection method
US8012869B2 (en) 2005-08-15 2011-09-06 Panasonic Corporation Bonded structure and bonding method
JP2007220822A (en) * 2006-02-15 2007-08-30 Matsushita Electric Ind Co Ltd Connection structure and its fabrication process
JP2009206407A (en) * 2008-02-29 2009-09-10 Morioka Seiko Instruments Inc Wire bonding method
JP2013051582A (en) * 2011-08-31 2013-03-14 Kyocera Crystal Device Corp Package and piezoelectric device
JP2020088047A (en) * 2018-11-19 2020-06-04 新日本無線株式会社 Semiconductor device and manufacturing method thereof

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