JP2003163563A - Piezoelectric device - Google Patents
Piezoelectric deviceInfo
- Publication number
- JP2003163563A JP2003163563A JP2001359653A JP2001359653A JP2003163563A JP 2003163563 A JP2003163563 A JP 2003163563A JP 2001359653 A JP2001359653 A JP 2001359653A JP 2001359653 A JP2001359653 A JP 2001359653A JP 2003163563 A JP2003163563 A JP 2003163563A
- Authority
- JP
- Japan
- Prior art keywords
- piezoelectric
- container
- acoustic wave
- electrode
- surface acoustic
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Withdrawn
Links
- 239000000853 adhesive Substances 0.000 claims abstract description 46
- 230000001070 adhesive effect Effects 0.000 claims abstract description 46
- 238000000605 extraction Methods 0.000 claims abstract description 26
- 239000000758 substrate Substances 0.000 claims abstract description 21
- 238000010897 surface acoustic wave method Methods 0.000 description 59
- 239000000919 ceramic Substances 0.000 description 7
- PXHVJJICTQNCMI-UHFFFAOYSA-N Nickel Chemical compound [Ni] PXHVJJICTQNCMI-UHFFFAOYSA-N 0.000 description 6
- 238000000034 method Methods 0.000 description 5
- 229910052751 metal Inorganic materials 0.000 description 4
- 239000002184 metal Substances 0.000 description 4
- 230000001105 regulatory effect Effects 0.000 description 4
- 229910052782 aluminium Inorganic materials 0.000 description 3
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 3
- 230000006835 compression Effects 0.000 description 3
- 238000007906 compression Methods 0.000 description 3
- 238000010586 diagram Methods 0.000 description 3
- PCHJSUWPFVWCPO-UHFFFAOYSA-N gold Chemical compound [Au] PCHJSUWPFVWCPO-UHFFFAOYSA-N 0.000 description 3
- 229910052737 gold Inorganic materials 0.000 description 3
- 239000010931 gold Substances 0.000 description 3
- 239000011347 resin Substances 0.000 description 3
- 229920005989 resin Polymers 0.000 description 3
- 238000010438 heat treatment Methods 0.000 description 2
- 229910052759 nickel Inorganic materials 0.000 description 2
- 238000004382 potting Methods 0.000 description 2
- WSMQKESQZFQMFW-UHFFFAOYSA-N 5-methyl-pyrazole-3-carboxylic acid Chemical compound CC1=CC(C(O)=O)=NN1 WSMQKESQZFQMFW-UHFFFAOYSA-N 0.000 description 1
- 229910000531 Co alloy Inorganic materials 0.000 description 1
- 239000004593 Epoxy Substances 0.000 description 1
- 229910000640 Fe alloy Inorganic materials 0.000 description 1
- 229910000990 Ni alloy Inorganic materials 0.000 description 1
- 229910045601 alloy Inorganic materials 0.000 description 1
- 239000000956 alloy Substances 0.000 description 1
- 239000003795 chemical substances by application Substances 0.000 description 1
- 239000010941 cobalt Substances 0.000 description 1
- GUTLYIVDDKVIGB-UHFFFAOYSA-N cobalt atom Chemical compound [Co] GUTLYIVDDKVIGB-UHFFFAOYSA-N 0.000 description 1
- 238000007796 conventional method Methods 0.000 description 1
- 239000013078 crystal Substances 0.000 description 1
- 230000005284 excitation Effects 0.000 description 1
- 239000010408 film Substances 0.000 description 1
- 238000002347 injection Methods 0.000 description 1
- 239000007924 injection Substances 0.000 description 1
- 229910000833 kovar Inorganic materials 0.000 description 1
- GQYHUHYESMUTHG-UHFFFAOYSA-N lithium niobate Chemical compound [Li+].[O-][Nb](=O)=O GQYHUHYESMUTHG-UHFFFAOYSA-N 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
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- 230000035699 permeability Effects 0.000 description 1
- 238000007789 sealing Methods 0.000 description 1
- 230000008961 swelling Effects 0.000 description 1
- 239000010409 thin film Substances 0.000 description 1
- 238000003466 welding Methods 0.000 description 1
Landscapes
- Surface Acoustic Wave Elements And Circuit Networks Thereof (AREA)
- Piezo-Electric Or Mechanical Vibrators, Or Delay Or Filter Circuits (AREA)
Abstract
Description
【発明の詳細な説明】
【０００１】
【発明の属する技術分野】本発明は携帯用電子機器等に
使用される圧電素子を利用したフィルタや発振器などの
圧電装置に関するものである。
【０００２】
【従来の技術】周波数変化が小さい安定な電気特性を得
るために、圧電振動素子を片側保持する構造とした従来
の圧電装置の例として、特開平１０−１９０４０２号公
報に開示されるような弾性表面波フィルタや、ＷＯ９５
／２４０７５号公報に開示されるような弾性表面波共振
子等がある。
【０００３】特開平１０−１９０４０２号公報について
図４に示す。４１は弾性表面波素子、４２は容器、４３
はボンディングワイヤである。弾性表面波素子４１は圧
電性素子４１０の表面に導体薄膜からなる電極４１１、
例えば櫛歯状電極（ＩＤＴ：Ｉｎｔｅｒ Ｄｉｇｉｔａ
ｌ Ｔｒａｎｓｄｕｃｅｒ）、反射器等が形成されてお
り、接着剤４１２によって容器４２の搭載面に固定され
ている。弾性表面波素子４１と容器４２の電気的接続は
ボンディングワイヤ４３で行われており、弾性表面波素
子４１の表面に形成された電極４１１と容器４２の段差
部４５に形成された接続パッド４４がボンディングワイ
ヤ４３で接続されている。なお、容器４２の開口部は蓋
体により封止されるが説明を簡単にするために省略して
いる。
【０００４】次に、ＷＯ９５／２４０７５号公報につい
て図５（ａ）（ｂ）に示す。図５（ａ）は従来の弾性表
面波共振子の蓋体を省略した平面図、図５（ｂ）は図５
（ａ）のＡ−Ａ線概略断面図を示す。弾性表面波素子５
１は導電性接着剤５２によって容器５３の電極と接続さ
れており、さらに保持強度を向上し短絡を防止するた
め、弾性表面波素子５１の一方端の中央部で絶縁性接着
剤５４によって容器５３に固定されている。導電性接着
剤５２と絶縁性接着剤５４は弾性表面波素子５１の上面
から塗布されており、弾性表面波素子５１の上面よりも
３００μｍから５００μｍ程度盛り上がるように塗布さ
れている。
【０００５】
【発明が解決しようとする課題】図４に示す従来技術で
は、弾性表面波素子４１と容器４２との電気的接続はボ
ンディングワイヤ４３で行われており、弾性表面波素子
４１の表面に形成された電極４１１と容器４２の段差部
４５に形成された接続パッド４４をボンディングワイヤ
４３で接続する構造になっている。
【０００６】よって、このような構造の圧電装置では、
ワイヤボンディングを行うために幅２００μｍから３０
０μｍ程度の接続パッド４４が形成された段差部４５が
必要になり小型化が困難であった。また、ボンディング
ワイヤ４３の引き回しのために容器４２の深さを十分に
取り、蓋体（不図示）との接触を防止していたが、容器
４２の深さを十分にとると圧電装置を低背化することが
困難であった。
【０００７】一方、図５に示す従来技術では、弾性表面
波素子５１と容器５３の電気的接続は導電性接着剤５２
によって行われているが、導電性接着剤５２の流動性に
よる電気的短絡を防止するため、異なる電極間の距離を
一定以上狭くすることができず小型化が困難であり、更
にフィルタ等の電極数の多いものには実用上適用不可能
であった。また、電気的接続および保持のため弾性表面
波共振素子５１の上面に導電性接着剤５２および絶縁性
接着剤５４が、大きく盛り上がるように塗布されている
ため、高さ寸法においても小型化が困難で低背化の要求
に応えることができなかった。また、接着剤を上から弾
性表面波素子５１と容器５３の段差部とに跨るように塗
布しているため、弾性表面波素子５１と容器５３の段差
部との間の上下に重なる部分に接着剤を塗布する場合と
比較して２倍の接着面積を必要とし、接着強度を確保し
ようとすると接着面積が大きくなって、小型化が困難で
あるという問題があった。
【０００８】更に、保持強度を向上させるための絶縁性
接着剤５４の塗布範囲は弾性表面波素子５１の一方端側
の中央部のみであり、その両側に導電性接着剤が塗布さ
れるもののその接着強度は低く、接着強度の高い絶縁性
接着剤では一部分しか接合されないので落下衝撃に弱い
という欠点もあった。
【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、小型化、低背化が可能であり、
かつ、片側保持でありながら保持強度に優れ、落下衝撃
等の信頼性性能の優れた圧電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
めに本発明は、四角形状をなす圧電基板に振動電極を形
成し、前記圧電基板の下面の一方端面側に振動電極から
延出した引出電極を有する圧電振動素子と、キャビティ
を有し、かつ該キャビティの底面に前記圧電振動素子を
載置する載置部と、該載置部に形成した電極パッドとを
有する容器とからなり、該容器のキャビティ内に前記圧
電振動素子を収容するとともに、前記圧電振動素子の引
出電極と前記容器の電極パッドとを導電性バンプを介し
て接続してなる圧電装置であって、前記載置部と圧電振
動素子下面とで形成される間隙及び前記圧電振動素子の
一方端面と該端面に対向するキャビティの内壁面とで形
成される間隙のそれぞれに絶縁性接着剤を配設したこと
を特徴とする圧電装置である。
【作用】本発明の圧電装置によれば、圧電振動素子の引
出電極が容器の電極パッドに導電性バンプを介して接続
されるため、電極パッドは引出電極の直下に形成すれば
よい。従って、従来ワイヤボンディングのために必要と
されていた圧電振動素子の周囲に設けた容器側の電極パ
ッドが必要でなくなるために、電極パッドが形成される
領域分、容器を小型化することができる。また、ボンデ
ィングワイヤの引き回しのために容器の深さを十分に取
り、蓋体との接触を防止していたが、その必要が無くな
り低背化が可能になる。
【００１１】また、従来のような導電性接着剤で接合す
る場合は引き出し電極同士の間に充分な距離を取って導
電性接着剤が拡がっても異なる引出電極同士が短絡しな
いようにする必要があり小型化が困難で、更にフィルタ
等のように引き出し電極数が多いものには実用上適用不
可能であったが、電気的に圧電振動素子の引出電極と容
器の電極パッドとを導電性バンプにより接続し、機械的
に絶縁性樹脂でそれぞれを固定することで短絡なく引出
電極間を狭く形成することができ全体として小型化が可
能となる。従って、フィルタ等のように引き出し電極数
が多いものにも適用可能となる。
【００１２】更に、載置部と圧電振動素子下面とで形成
される間隙に絶縁性接着剤が介在するだけでなく、圧電
振動素子の一方端面とその端面と対面するキャビティの
内壁面で形成される間隙にも絶縁性接着剤が配設されて
いるので、接合強度が強固になり充分な接合強度を得る
ことが出来る。また、従来圧電振動素子の主面から盛り
上がる形で塗布されていた導電性接着剤及び絶縁性接着
剤が無くなる為、圧電装置の更なる低背化を達成するこ
とができる。
【００１３】
【発明の実施の形態】以下、本発明の圧電装置を図面に
基づいて詳説するが、理解のため、弾性表面波を用いた
弾性表面波装置について説明する。図１は本発明の弾性
表面波装置１の外観斜視図、図２は本発明の弾性表面波
装置１の中央線断面図、図３は弾性表面波素子の構造を
説明する図であって、（ａ）はその下面図、（ｂ）は側
面図である。図において、１は弾性表面波装置であり、
弾性表面波装置１は、弾性表面波素子２、筐体状の容器
３、及び蓋体４により構成される。
【００１４】弾性表面波素子２は圧電基板１１の下面に
互いに対向した櫛歯状電極（励振電極）１２、１２と、
この櫛歯状電極１２、１２の両外側に反射器１３、１３
と、櫛歯状電極１２、１２から複数の接続電極１４を介
して引き出された複数の引出電極１５とがそれぞれ形成
されている。圧電基板１１は矩形状の基板であり、その
材質としてはタンタル酸リチウム、ニオブ酸リチウム、
水晶等が用いられる。また、櫛歯状電極１２、１２及び
反射器１３、１３、接続電極１４はアルミニウムまたは
アルミニウムを主成分とする金属にて形成される。櫛歯
状電極１２から引き出す複数の接続電極１４は圧電基板
１１下面の一方端面２０側に向けて形成される。
【００１５】更に、接続電極１４に接続される複数の引
出電極１５はアルミニウムや金等からなり、圧電基板１
１下面の一方端面２０側の幅方向に複数形成されてい
る。また、引出電極１５上には後述の容器３に形成され
ている電極パッド８とフリップチップボンディング法に
て接合するために導電性バンプ１６が形成されている。
【００１６】なお、本実施の形態では櫛歯状電極１２を
圧電基板１１の下面に形成したがこれに限定されず圧電
基板１１の上面に形成しても良い。この場合、引出電極
１５は圧電基板１１の下面に形成されなければ成らず、
その際の接続電極１４は圧電基板１１の上面から下面に
引き出すように形成する。
【００１７】容器３は図２に示すように、複数のセラミ
ック基板が複数積層されたセラミック多層基板３０を有
し、そのセラミック多層基板３０上にシールリング５
が、また、シールリング５上に蓋体４が形成されてい
る。
【００１８】セラミック多層基板３０は直方体状の筐体
が用いられ、直方体状のキャビティを有し、その下面の
4隅には複数の外部端子電極９が形成されている。
【００１９】このキャビティ６の底面の一方端側には弾
性表面波素子２を搭載する載置部７が形成されている。
載置部７は図２のように、その上面がキャビティ６底面
から一段高くなったセラミック基板からなる段差７０上
に設けられれている。載置部７には弾性表面波素子２の
導電性バンプ１６が接続される電極パッド８が形成され
る。
【００２０】また、この段差７０は、後述のように絶縁
性接着剤１７が硬化以前の流動性により弾性表面波素子
２の櫛歯状電極１２と反射器１３が形成されている振動
領域へ流れ出し電気特性を劣化させることの無いよう、
絶縁性接着剤１７の流れる長さを規制する役割をもち、
従って載置部７の長さＸの寸法は弾性表面波素子２の最
低限の接着強度及び必要な振動領域の寸法の両面より決
定される。特に、載置部７と弾性表面波振動素子２下面
とで形成される間隙に絶縁性接着剤１７が介在するだけ
でなく弾性表面波振動素子２の一方端面と対面するキャ
ビティ６の内壁面で形成される間隙にも絶縁性接着剤１
７が配設されるために、従来の導電性接着剤による段差
部への保持に較べて載置部７の長さＸを短縮することが
できる。この結果、容器３の長さをおさえることができ
る。
【００２１】なお、本実施の形態では段差７０の上面に
載置部７が設けられた例を示したがこれに限定されず、
キャビティ６底面の一部を載置部７とし、この位置に直
接電極パッド８を形成したものでも良い。
【００２２】外部端子電極９は不図示のマザーボードと
接続するためのものであり、外部端子電極９は載置部７
の電極パッド８からセラミック多層基板３０内に形成し
た内部配線パターン１０によって接続されている。
【００２３】１７は絶縁性接着剤であり、この絶縁性接
着剤１７はアンダーフィル樹脂とも呼ばれ、フリップチ
ップ実装した電子部品の実装領域に形成されるものであ
る。絶縁性接着剤１７が形成される領域は載置部７と弾
性表面波素子２下面とで形成される間隙ｇ1及び弾性表
面波素子２の一方端面２０とその一方端面２０と対面す
るキャビティ６の内壁面１８で形成される間隙ｇ2であ
る。この時、間隙ｇ2は、弾性表面波装置１の小型化の
ため約１００μｍ程度であることが望ましい。
【００２４】また、絶縁性接着剤１７は弾性表面波素子
２の下面に形成された櫛歯状電極１２、反射器１３等に
付着しないように、載置部７の段差７０で規制されてい
る。なお、段差７０を形成しない場合、即ち、直接キャ
ビティ６底面に直接電極パッド８を形成する場合には図
３（ａ）の点線に示す反射器１３と接続電極１５との間
の領域でキャビティ６底面との間に絶縁性接着剤１７の
流れを規制する規制部材２１を形成してもよい。絶縁性
接着剤１７としては、例えば、紫外線照射や加熱により
硬化する低粘度のエポキシ系樹脂が用いられる。
【００２５】弾性表面波素子２の一方端を容器内壁面１
８に近づけて配置し、絶縁性接着剤１７によって、弾性
表面波素子２の下面とその一方端面２０が載置部７とキ
ャビティ６の内壁面１８に強固に固定される。即ち、弾
性表面波素子２の一方端端面２０と容器３内壁面１８の
双方からの保持力が働き、下面の接着面積は増やすこと
なく強固な固定を行う。また、絶縁性接着剤１７は浸透
性、流動性を考慮し比較的低粘度なものを選択すること
により、弾性表面波素子２の一方端の端面と容器３内壁
面の間にポッティングした場合、速やかに間隙に浸透
し、載置部７の側面と底面を強固に接着することができ
る。特にポッティング箇所で低粘度の絶縁性接着剤１７
は間隙ｇ2に吸い込まれるので上側にはほとんど残ら
ず、高さが抑えられるために容器３の深さを抑えても蓋
体４と接触することがなく低背化を達成することができ
る。
【００２６】シールリング５は鉄とニッケルとコバルト
の合金等からなり、蓋体４を載置してシーム封止を行
う。蓋体４はコバールや４２アロイ等の金属もしくは表
面に金属膜を形成したセラミック等からなり、必要に応
じて表面にニッケルや金等のメッキが施される。また、
シールリング５も必要に応じてニッケルや金等のメッキ
が施される。
【００２７】ここで、弾性表面波装置１は以下の手順で
作製される。まず、弾性表面波素子２は、図３（ｂ）に
示すように櫛歯状電極１２が下に向くフェイスダウンで
搭載され、予め圧電基板１１下面の一方端面側の引出電
極１５上に形成された導電性バンプ１６と、容器３の載
置部７に形成されている電極パッド８とが加熱圧着、超
音波圧着、加熱超音波圧着等により接合される。次に、
この導電性バンプ１６によって接続されている弾性表面
波素子２の一方端面２０とそれに対向するキャビティ６
の内壁面１８とで形成される間隙ｇ2に絶縁性接着剤１
７を注入すると、弾性表面波素子２の下面と載置部７と
の間に形成される間隙ｇ1にも絶縁性接着剤１７が入り
込み、熱処理等により硬化させる。
【００２８】その後、蓋体４を筐体状容器３のシールリ
ング５上に載置し、シーム溶接等の工法により気密封止
され弾性表面波装置となる。
【００２９】かくして、本発明の構成によれば、弾性表
面波素子２の引出電極１５と容器２の載置部７の電極パ
ッド８とを導電性バンプ１６を介して電気的に接続する
とともに、圧電振動素子２の下面とその一方端面２０
が、載置部７とキャビティ６の内壁面１８のそれぞれに
絶縁性接着剤１７にて機械的に固定される。
【００３０】従って、引出電極１５と電極パッド８とが
電気的に確実に接続されるとともに、弾性表面波素子２
の一方端端面２０と容器３内壁面１８の双方からの保持
力が働き、下面の接着面積は増やすことなく強固な固定
を行うことができる。これにより落下衝撃等に対する信
頼性の高い弾性表面波装置１を提供することができる。
【００３１】また、弾性表面波素子２の引出電極１５が
容器３の電極パッド８に導電性バンプ１６を介して接続
されるため、電極パッド８は引出電極１５の直下に形成
すればよい。従って、従来ワイヤボンディングのために
弾性表面波素子２の周囲の容器に形成していた電極パッ
ドが不要になるため、容器を小型化することができる。
また、ボンディングワイヤの引き回しのために容器の深
さを十分に取り蓋体との接触を防止していたが、その必
要が無くなり低背化が可能になる。
【００３２】また、引出電極１５と電極パッド８とをバ
ンプ１６を用いてフリップチップボンディング法により
接合しているので、弾性表面波素子２に形成する各引出
電極１５の異なる電極同士が短絡することは無くなり、
各引出電極１５間を狭く形成することができるため圧電
振動素子２及び容器３を小型化することが出来、更にフ
ィルタ等の引き出し電極数の多いものにも適用可能とな
る。
【００３３】上記実施形態は、本発明を説明するための
ものであって、特許請求の範囲に記載の発明を限定する
ものではない。また本発明の各部構成は上記実施形態に
限らず特許請求の範囲に記載の技術的範囲内で種々の変
形が可能である。例えば、本実施形態の説明では縦結合
型ダブルモードＳＡＷ共振子フィルタの図を示したが、
トランスバーサル型フィルタやラダー型フィルタ等の他
の弾性表面波フィルタや、共振器や遅延線のような他の
圧電装置においても本発明は適用可能である。
【００３４】また、上述の導電性バンプ１６は、例えば
ワイヤボンディング技術を応用したスタッドバンプを用
いればよりいっそうの小型化が図れる。
【００３５】
【発明の効果】本発明による圧電装置は、圧電振動素子
の引出電極と、容器の圧電振動素子用載置部に形成した
電極パッドとを導電性バンプを介して接続するととも
に、その載置部と圧電振動素子下面とで形成される間隙
及び圧電振動素子の一方端面とその端面と対面するキャ
ビティの内壁面とで形成される間隙のそれぞれに絶縁性
接着剤を配設したため、電気的接続が確実に行われると
ともに、保持力が強固になり、耐衝撃性等の信頼性性能
が大幅に向上し、かつ小型化、低背化が可能となり、更
にフィルタ等の引き出し電極数の多いものにも適用可能
となる。
【００３６】その結果、周波数変化が小さい安定した電
気特性を有したまま小型・低背化され、かつ接続強度も
向上し、実装状態での充分な落下強度が要求される携帯
型電子機器においても問題なく使用できる圧電装置を提
供できる。Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a piezoelectric device such as a filter and an oscillator using a piezoelectric element used in portable electronic equipment and the like. 2. Description of the Related Art Japanese Patent Application Laid-Open No. H10-190402 discloses an example of a conventional piezoelectric device having a structure in which a piezoelectric vibrating element is held on one side in order to obtain stable electric characteristics with a small frequency change. Surface acoustic wave filter such as WO95
/ 24075 discloses a surface acoustic wave resonator and the like. FIG. 4 shows JP-A-10-190402. 41 is a surface acoustic wave element, 42 is a container, 43
Is a bonding wire. The surface acoustic wave element 41 has an electrode 411 made of a conductive thin film on the surface of the piezoelectric element 410.
For example, a comb-shaped electrode (IDT: Inter Digita)
1 Transducer), a reflector, and the like are formed, and are fixed to the mounting surface of the container 42 by the adhesive 412. Electrical connection between the surface acoustic wave element 41 and the container 42 is made by a bonding wire 43, and an electrode 411 formed on the surface of the surface acoustic wave element 41 and a connection pad 44 formed on a step 45 of the container 42. They are connected by bonding wires 43. The opening of the container 42 is sealed by a lid, but is omitted for the sake of simplicity. Next, WO95 / 24075 is shown in FIGS. 5 (a) and 5 (b). FIG. 5A is a plan view of the conventional surface acoustic wave resonator in which a cover is omitted, and FIG.
FIG. 2A is a schematic cross-sectional view taken along line AA of FIG. Surface acoustic wave element 5
Numeral 1 is connected to the electrode of the container 53 by a conductive adhesive 52. In order to further improve the holding strength and prevent a short circuit, the center of one end of the surface acoustic wave element 51 is connected to the container 53 by an insulating adhesive 54. Fixed to. The conductive adhesive 52 and the insulating adhesive 54 are applied from the upper surface of the surface acoustic wave element 51, and are applied so as to rise from the upper surface of the surface acoustic wave element 51 by about 300 μm to 500 μm. In the prior art shown in FIG. 4, the electrical connection between the surface acoustic wave element 41 and the container 42 is made by a bonding wire 43, and the surface of the surface acoustic wave element 41 is And the connection pad 44 formed on the step portion 45 of the container 42 is connected by a bonding wire 43. Accordingly, in a piezoelectric device having such a structure,
Width 200 μm to 30 to perform wire bonding
A step 45 on which a connection pad 44 of about 0 μm is formed is required, and miniaturization is difficult. In addition, the container 42 has a sufficient depth for routing the bonding wire 43 to prevent contact with a lid (not shown). However, if the container 42 has a sufficient depth, the piezoelectric device may be lowered. It was difficult to erect. On the other hand, in the prior art shown in FIG. 5, an electrical connection between the surface acoustic wave element 51 and the container 53 is made by a conductive adhesive 52.
However, in order to prevent an electrical short circuit due to the fluidity of the conductive adhesive 52, the distance between different electrodes cannot be reduced more than a certain value, making it difficult to reduce the size. It was not practically applicable to a large number. In addition, since the conductive adhesive 52 and the insulating adhesive 54 are applied on the upper surface of the surface acoustic wave resonator 51 for electrical connection and holding so as to be greatly raised, miniaturization is difficult even in the height dimension. Could not meet the demand for lower profile. Further, since the adhesive is applied so as to straddle the surface acoustic wave element 51 and the step portion of the container 53 from above, the adhesive is adhered to a vertically overlapping portion between the surface acoustic wave element 51 and the step portion of the container 53. This requires twice the bonding area as compared with the case where the agent is applied, and there is a problem in that if the bonding strength is to be ensured, the bonding area becomes large and miniaturization is difficult. Further, the application range of the insulating adhesive 54 for improving the holding strength is only the central portion on one end side of the surface acoustic wave element 51, and the conductive adhesive is applied on both sides thereof. There is also a disadvantage that the adhesive strength is low, and the insulating adhesive having high adhesive strength is only partially bonded, so that the adhesive is weak against a drop impact. The present invention has been made in view of the above-mentioned problems, and its object is to reduce the size and height of the device.
Another object of the present invention is to provide a piezoelectric device which is excellent in holding strength while being one-sided holding and has excellent reliability performance such as drop impact. [0010] In order to solve the above-mentioned problems, the present invention is to form a vibrating electrode on a square-shaped piezoelectric substrate, and connect the vibrating electrode to one end face side of the lower surface of the piezoelectric substrate. A container having a piezoelectric vibrating element having an extended extraction electrode, a cavity having a cavity, and a mounting portion for mounting the piezoelectric vibrating element on a bottom surface of the cavity, and an electrode pad formed on the mounting portion; A piezoelectric device comprising the piezoelectric vibrating element housed in a cavity of the container and connecting an extraction electrode of the piezoelectric vibrating element and an electrode pad of the container via a conductive bump. An insulating adhesive is provided in each of a gap formed between the mounting portion and the lower surface of the piezoelectric vibrating element and a gap formed between one end surface of the piezoelectric vibrating element and an inner wall surface of the cavity opposed to the end surface. Especially This is a piezoelectric device. According to the piezoelectric device of the present invention, since the extraction electrode of the piezoelectric vibrating element is connected to the electrode pad of the container via the conductive bump, the electrode pad may be formed immediately below the extraction electrode. Therefore, since the electrode pad on the container side provided around the piezoelectric vibrating element, which is conventionally required for wire bonding, is not required, the size of the container can be reduced by the area where the electrode pad is formed. . In addition, the container has a sufficient depth for routing the bonding wire to prevent contact with the lid. However, the necessity is eliminated and the height can be reduced. In the case of bonding with a conventional conductive adhesive, it is necessary to provide a sufficient distance between the lead electrodes so that different lead electrodes do not short-circuit even if the conductive adhesive spreads. Although it was difficult to reduce the size, and it was not practically applicable to those having a large number of extraction electrodes, such as filters, etc., electrically connecting the extraction electrodes of the piezoelectric vibrating element and the electrode pads of the container to conductive bumps By connecting each other and mechanically fixing each with an insulating resin, it is possible to form a narrow space between the extraction electrodes without short-circuiting, and to reduce the size as a whole. Therefore, the present invention can be applied to a filter having a large number of extraction electrodes, such as a filter. Furthermore, not only is the insulating adhesive interposed in the gap formed between the mounting portion and the lower surface of the piezoelectric vibrating element, but it is also formed by one end face of the piezoelectric vibrating element and the inner wall surface of the cavity facing the end face. Since the insulating adhesive is also provided in the gap, the bonding strength is increased, and sufficient bonding strength can be obtained. Further, since the conductive adhesive and the insulating adhesive which have been applied in the form of swelling from the main surface of the piezoelectric vibration element in the related art are eliminated, the height of the piezoelectric device can be further reduced. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a piezoelectric device of the present invention will be described in detail with reference to the drawings. For understanding, a surface acoustic wave device using a surface acoustic wave will be described. FIG. 1 is an external perspective view of a surface acoustic wave device 1 of the present invention, FIG. 2 is a center line cross-sectional view of the surface acoustic wave device 1 of the present invention, and FIG. (A) is a bottom view, and (b) is a side view. In the figure, 1 is a surface acoustic wave device,
The surface acoustic wave device 1 includes a surface acoustic wave element 2, a case-like container 3, and a lid 4. The surface acoustic wave element 2 has comb-shaped electrodes (excitation electrodes) 12 and 12 facing each other on the lower surface of a piezoelectric substrate 11.
Reflectors 13, 13 are provided on both outer sides of the comb-shaped electrodes 12, 12, respectively.
And a plurality of extraction electrodes 15 which are extracted from the comb-shaped electrodes 12 and 12 via the plurality of connection electrodes 14, respectively. The piezoelectric substrate 11 is a rectangular substrate, and its material is lithium tantalate, lithium niobate,
Crystal or the like is used. The comb-shaped electrodes 12, 12, the reflectors 13, 13, and the connection electrode 14 are formed of aluminum or a metal containing aluminum as a main component. The plurality of connection electrodes 14 drawn from the comb-shaped electrode 12 are formed toward the one end surface 20 of the lower surface of the piezoelectric substrate 11. The plurality of extraction electrodes 15 connected to the connection electrodes 14 are made of aluminum, gold, or the like.
A plurality of the lower surfaces are formed in the width direction on the one end surface 20 side. A conductive bump 16 is formed on the extraction electrode 15 so as to be bonded to an electrode pad 8 formed on the container 3 described later by a flip chip bonding method. In the present embodiment, the comb-shaped electrode 12 is formed on the lower surface of the piezoelectric substrate 11, but is not limited to this, and may be formed on the upper surface of the piezoelectric substrate 11. In this case, the extraction electrode 15 must be formed on the lower surface of the piezoelectric substrate 11,
At this time, the connection electrode 14 is formed so as to be drawn from the upper surface of the piezoelectric substrate 11 to the lower surface. As shown in FIG. 2, the container 3 has a ceramic multilayer substrate 30 in which a plurality of ceramic substrates are laminated, and a seal ring 5 is provided on the ceramic multilayer substrate 30.
However, the lid 4 is formed on the seal ring 5. As the ceramic multilayer substrate 30, a rectangular parallelepiped housing is used, which has a rectangular parallelepiped cavity.
A plurality of external terminal electrodes 9 are formed at the four corners. A mounting portion 7 on which the surface acoustic wave element 2 is mounted is formed at one end of the bottom surface of the cavity 6.
As shown in FIG. 2, the mounting portion 7 is provided on a step 70 made of a ceramic substrate whose upper surface is one step higher than the bottom surface of the cavity 6. An electrode pad 8 to which the conductive bump 16 of the surface acoustic wave element 2 is connected is formed on the mounting portion 7. The step 70 flows out to the vibrating region of the surface acoustic wave element 2 where the comb-shaped electrode 12 and the reflector 13 are formed due to the fluidity before the insulating adhesive 17 is cured as described later. In order not to deteriorate the electrical characteristics,
It has the role of regulating the length of flow of the insulating adhesive 17,
Therefore, the dimension of the length X of the mounting portion 7 is determined based on both the minimum adhesive strength of the surface acoustic wave element 2 and the required size of the vibration area. In particular, not only is the insulating adhesive 17 interposed in the gap formed between the mounting portion 7 and the lower surface of the surface acoustic wave vibration element 2, but also the inner wall surface of the cavity 6 facing one end surface of the surface acoustic wave vibration element 2. Insulating adhesive 1 in gaps formed
Since the 7 is provided, the length X of the mounting portion 7 can be shortened as compared with the conventional method in which the conductive adhesive is used to hold the step portion. As a result, the length of the container 3 can be reduced. In this embodiment, an example in which the mounting portion 7 is provided on the upper surface of the step 70 has been described. However, the present invention is not limited to this.
A part of the bottom surface of the cavity 6 may be used as the mounting part 7 and the electrode pad 8 may be directly formed at this position. The external terminal electrodes 9 are for connecting to a motherboard (not shown).
Are connected by the internal wiring pattern 10 formed in the ceramic multi-layer substrate 30 from the electrode pad 8 of FIG. Reference numeral 17 denotes an insulating adhesive. The insulating adhesive 17 is also called an underfill resin and is formed in a mounting area of an electronic component mounted by flip-chip bonding. The area where the insulating adhesive 17 is formed is a gap g 1 formed between the mounting portion 7 and the lower surface of the surface acoustic wave element 2, one end face 20 of the surface acoustic wave element 2, and the cavity 6 facing the one end face 20. a gap g 2 which is formed by the inner wall surface 18 of the. At this time, it is desirable that the gap g 2 is about 100 μm to reduce the size of the surface acoustic wave device 1. Further, the insulating adhesive 17 is regulated by the step 70 of the mounting portion 7 so as not to adhere to the comb-like electrode 12, the reflector 13, etc. formed on the lower surface of the surface acoustic wave element 2. . When the step 70 is not formed, that is, when the electrode pad 8 is formed directly on the bottom surface of the cavity 6, the cavity 6 is formed in a region between the reflector 13 and the connection electrode 15 shown by a dotted line in FIG. A regulating member 21 for regulating the flow of the insulating adhesive 17 may be formed between the bottom surface and the bottom surface. As the insulating adhesive 17, for example, a low-viscosity epoxy-based resin that is cured by ultraviolet irradiation or heating is used. One end of the surface acoustic wave element 2 is
The lower surface of the surface acoustic wave element 2 and one end surface 20 thereof are firmly fixed to the mounting portion 7 and the inner wall surface 18 of the cavity 6 by the insulating adhesive 17. That is, the holding force from both the one end surface 20 of the surface acoustic wave element 2 and the inner wall surface 18 of the container 3 acts, and firm fixing is performed without increasing the bonding area of the lower surface. In addition, when the insulating adhesive 17 is selected to have a relatively low viscosity in consideration of permeability and fluidity, when the potting is performed between one end surface of the surface acoustic wave element 2 and the inner wall surface of the container 3, It quickly penetrates into the gap, and the side and bottom surfaces of the mounting portion 7 can be firmly bonded. In particular, a low-viscosity insulating adhesive 17 at a potting location.
Can be achieved hardly remain on the upper side so sucked into the gap g 2, the height not come into contact with the cover 4 also suppresses the depth of the container 3 to be suppressed low profile. The seal ring 5 is made of an alloy of iron, nickel and cobalt or the like, and performs seam sealing with the lid 4 placed thereon. The cover 4 is made of a metal such as Kovar or 42 alloy or a ceramic having a metal film formed on the surface, and the surface is plated with nickel or gold as needed. Also,
The seal ring 5 is also plated with nickel or gold as needed. Here, the surface acoustic wave device 1 is manufactured according to the following procedure. First, as shown in FIG. 3B, the surface acoustic wave element 2 is mounted face-down with the comb-shaped electrode 12 facing downward, and is formed in advance on the extraction electrode 15 on one end face side of the lower surface of the piezoelectric substrate 11. The conductive bump 16 and the electrode pad 8 formed on the mounting portion 7 of the container 3 are joined by heat compression, ultrasonic compression, heat ultrasonic compression, or the like. next,
One end face 20 of surface acoustic wave element 2 connected by conductive bump 16 and cavity 6 opposed thereto
Insulating adhesive in a gap g 2 formed by the inner wall surface 18 of 1
Injection of 7, also enters the insulating adhesive 17 in gap g 1 formed between the portion 7 placing with the lower surface of the surface acoustic wave element 2, it is cured by heat treatment or the like. Thereafter, the lid 4 is placed on the seal ring 5 of the housing 3 and hermetically sealed by a method such as seam welding to obtain a surface acoustic wave device. Thus, according to the configuration of the present invention, the extraction electrode 15 of the surface acoustic wave element 2 and the electrode pad 8 of the mounting portion 7 of the container 2 are electrically connected via the conductive bump 16 and Lower surface of piezoelectric vibrating element 2 and one end surface 20 thereof
Is mechanically fixed to the mounting portion 7 and the inner wall surface 18 of the cavity 6 with an insulating adhesive 17. Therefore, the extraction electrode 15 and the electrode pad 8 are securely connected electrically, and the surface acoustic wave element 2
The holding force from both the one end surface 20 and the inner wall surface 18 of the container 3 acts, and a firm fixing can be performed without increasing the bonding area of the lower surface. Thereby, it is possible to provide the surface acoustic wave device 1 having high reliability against a drop impact or the like. Further, since the extraction electrode 15 of the surface acoustic wave element 2 is connected to the electrode pad 8 of the container 3 via the conductive bump 16, the electrode pad 8 may be formed directly below the extraction electrode 15. Therefore, the electrode pads formed on the container around the surface acoustic wave element 2 for wire bonding in the related art become unnecessary, so that the container can be downsized.
Further, the depth of the container is sufficiently set to prevent the contact with the lid for routing the bonding wire. However, the necessity is eliminated and the height can be reduced. Further, since the extraction electrode 15 and the electrode pad 8 are joined by the flip chip bonding method using the bumps 16, different electrodes of the extraction electrodes 15 formed on the surface acoustic wave element 2 are short-circuited. Is gone,
Since the space between the extraction electrodes 15 can be formed narrow, the piezoelectric vibrating element 2 and the container 3 can be reduced in size, and can be applied to a filter or the like having a large number of extraction electrodes. The above embodiment is for describing the present invention, and does not limit the invention described in the claims. The configuration of each part of the present invention is not limited to the above embodiment, and various modifications can be made within the technical scope described in the claims. For example, in the description of the present embodiment, a diagram of the longitudinally-coupled double mode SAW resonator filter is shown.
The present invention is applicable to other surface acoustic wave filters such as transversal type filters and ladder type filters, and other piezoelectric devices such as resonators and delay lines. The size of the conductive bumps 16 can be further reduced by using, for example, stud bumps to which a wire bonding technique is applied. According to the piezoelectric device of the present invention, the extraction electrode of the piezoelectric vibrating element and the electrode pad formed on the mounting portion for the piezoelectric vibrating element of the container are connected via conductive bumps. Since an insulating adhesive is provided in each of the gap formed between the mounting portion and the lower surface of the piezoelectric vibrating element and the gap formed between one end face of the piezoelectric vibrating element and the inner wall face of the cavity facing the end face, In addition to reliable connection, the holding force is strengthened, the reliability performance such as impact resistance is greatly improved, and the size and height can be reduced, and the number of extraction electrodes such as filters is large. It can be applied to things. As a result, a portable electronic device which is required to have a small size, a low profile, a high connection strength, and a sufficient drop strength in a mounted state is required while having stable electric characteristics with a small frequency change. A piezoelectric device that can be used without any problem can be provided.
【図面の簡単な説明】
【図１】本発明の弾性表面波装置の外観斜視図である。
【図２】本発明の弾性表面波装置の中央線断面図であ
る。
【図３】本発明の弾性表面波素子の構造を説明する図で
あって（ａ）はその下面図、（ｂ）は側面図である。
【図４】従来の弾性表面波装置の中央線断面図である。
【図５】従来の弾性表面波装置であって、（ａ）は金属
製蓋体を除いたときの下面説明図であり、（ｂ）はＡ−
Ａ線概略断面図である。
【符号の説明】
１・・・・・弾性表面波装置
２・・・・・弾性表面波素子
３・・・・・容器
４・・・・・蓋体
７・・・・・載置部
８・・・・・電極パッド
１２・・・・櫛歯状電極
１３・・・・反射器
１４・・・・接続電極
１５・・・・引出電極
１６・・・・導電性バンプ
１７・・・・絶縁性接着剤
１８・・・・内壁面BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an external perspective view of a surface acoustic wave device according to the present invention. FIG. 2 is a center line cross-sectional view of the surface acoustic wave device of the present invention. 3A and 3B are diagrams illustrating the structure of a surface acoustic wave device according to the present invention, wherein FIG. 3A is a bottom view and FIG. 3B is a side view. FIG. 4 is a sectional view taken along the center line of a conventional surface acoustic wave device. 5A and 5B are diagrams illustrating a conventional surface acoustic wave device, in which FIG. 5A is a lower surface explanatory view when a metal lid is removed, and FIG.
FIG. 3 is a schematic sectional view taken along line A. [Description of Signs] 1... Surface Acoustic Wave Device 2... Surface Acoustic Wave Element 3... Container 4... Lid 7. ······· Electrode pad 12 ···· Comb-toothed electrode 13 ····· Reflector 14 ······ Connection electrode 15 ······································· Insulating adhesive 18 ... Inner wall
───────────────────────────────────────────────────── フロントページの続き Ｆターム(参考） 5J097 AA29 BB01 BB11 DD24 EE08 FF03 GG02 GG03 GG04 HA04 JJ02 JJ09 JJ10 KK10 5J108 AA07 CC04 EE03 EE07 EE17 FF11 FF13 GG03 KK03 ────────────────────────────────────────────────── ─── Continuation of front page F term (reference) 5J097 AA29 BB01 BB11 DD24 EE08 FF03 GG02 GG03 GG04 HA04 JJ02 JJ09 JJ10 KK10 5J108 AA07 CC04 EE03 EE07 EE17 FF11 FF13 GG03 KK03
Claims (1)
極を形成し、前記圧電基板の下面の一方端面側に振動電
極から延出した引出電極を有する圧電振動素子と、 キャビティを有し、かつ該キャビティの底面に前記圧電
振動素子を載置する載置部と、該載置部に形成した電極
パッドとを有する容器とからなり、該容器のキャビティ
内に前記圧電振動素子を収容するとともに、前記圧電振
動素子の引出電極と前記容器の電極パッドとを導電性バ
ンプを介して接続してなる圧電装置であって、 前記載置部と圧電振動素子下面とで形成される間隙及び
前記圧電振動素子の一方端面と該端面に対向するキャビ
ティの内壁面とで形成される間隙のそれぞれに絶縁性接
着剤を配設したことを特徴とする圧電装置。Claims: 1. A piezoelectric vibrating element comprising: a vibrating electrode formed on a main surface of a rectangular piezoelectric substrate; and a lead electrode extending from the vibrating electrode on one end surface of a lower surface of the piezoelectric substrate. And a container having a cavity, and a mounting portion for mounting the piezoelectric vibrating element on the bottom surface of the cavity, and a container having an electrode pad formed on the mounting portion. A piezoelectric device containing a piezoelectric vibration element and connecting an extraction electrode of the piezoelectric vibration element and an electrode pad of the container via a conductive bump, wherein the mounting portion and the lower surface of the piezoelectric vibration element A piezoelectric device, wherein an insulating adhesive is disposed in each of a gap formed and a gap formed between one end surface of the piezoelectric vibrating element and an inner wall surface of a cavity opposed to the end surface.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2001359653A JP2003163563A (en) | 2001-11-26 | 2001-11-26 | Piezoelectric device |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2001359653A JP2003163563A (en) | 2001-11-26 | 2001-11-26 | Piezoelectric device |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JP2003163563A true JP2003163563A (en) | 2003-06-06 |
Family
ID=19170615
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP2001359653A Withdrawn JP2003163563A (en) | 2001-11-26 | 2001-11-26 | Piezoelectric device |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JP2003163563A (en) |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2005111142A (en) * | 2003-10-10 | 2005-04-28 | Olympus Corp | Capsule for medical use |
| JP2007013444A (en) * | 2005-06-29 | 2007-01-18 | Daishinku Corp | Piezo-electric oscillating device and method for manufacturing the same |
| US8107252B2 (en) | 2008-09-26 | 2012-01-31 | Seiko Epson Corporation | Mounting structure of electronic component and method of manufacturing electronic component |
| CN107040211A (en) * | 2015-10-26 | 2017-08-11 | 精工爱普生株式会社 | Oscillation module, electronic equipment and moving body |
-
2001
- 2001-11-26 JP JP2001359653A patent/JP2003163563A/en not_active Withdrawn
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2005111142A (en) * | 2003-10-10 | 2005-04-28 | Olympus Corp | Capsule for medical use |
| JP2007013444A (en) * | 2005-06-29 | 2007-01-18 | Daishinku Corp | Piezo-electric oscillating device and method for manufacturing the same |
| US8107252B2 (en) | 2008-09-26 | 2012-01-31 | Seiko Epson Corporation | Mounting structure of electronic component and method of manufacturing electronic component |
| US8867224B2 (en) | 2008-09-26 | 2014-10-21 | Seiko Epson Corporation | Mounting structure of electronic component and method of manufacturing electronic component |
| CN107040211A (en) * | 2015-10-26 | 2017-08-11 | 精工爱普生株式会社 | Oscillation module, electronic equipment and moving body |
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Legal Events
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| A621 | Written request for application examination |
Free format text: JAPANESE INTERMEDIATE CODE: A621 Effective date: 20040518 |
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