JP3882537B2

JP3882537B2 - Electrode electrode forming method

Info

Publication number: JP3882537B2
Application number: JP2001185934A
Authority: JP
Inventors: 靖弘森本; 昌信藤田
Original assignee: Murata Manufacturing Co Ltd
Current assignee: Murata Manufacturing Co Ltd
Priority date: 2001-06-20
Filing date: 2001-06-20
Publication date: 2007-02-21
Anticipated expiration: 2021-06-20
Also published as: JP2003007575A

Description

【０００１】
【発明の属する技術分野】
本発明は電子部品の電極形成方法、特に表面実装型電子部品における外部電極を形成するのに適した電極形成方法に関するものである。
【０００２】
【従来の技術】
近年、回路の小型化に伴い、リード付き部品に代わって表面実装型（チップ型）の電子部品が広く用いられている。この種の表面実装型電子部品として、例えば特開２０００−２８６６６５号公報に記載のように、基板の上に圧電共振子を搭載し、圧電共振子を覆うキャップを基板に取り付けた圧電共振部品が提案されている。基板の両端部および中央部の外面には３本の外部電極が形成されており、両端部の外部電極は基板を鉢巻き状に周回している。また、中央部の外部電極は、その上面部分が欠如している。
【０００３】
【発明が解決しようとする課題】
上記構造の電子部品において、基板に鉢巻き状の外部電極を形成するには、スパッタリング法を用いるのが通例である。しかし、基板の４面に電極を形成するには、スパッタリングを４回実施しなければならない。スパッタリングでは電極形成部以外をマスキングする必要があるので、工程数が多く、コスト高になる。
【０００４】
一方、転写法を用いて外部電極を形成する方法もある。例えば特開平２−３３９０８号公報には、凹溝に導電ペーストを充填した転写版の表面に電子部品の側端部を押し付け、導電ペーストを部品の３面に同時に転写する方法が提案されている。しかし、この方法では電子部品の側端部に電極を形成できるものの、鉢巻き状に周回する電極は形成できない。
【０００５】
そこで、転写法とスパッタリング法とを併用して鉢巻き状の電極を形成する方法の一例を図１９に示す。
図１９の（ａ）のように、１回目の転写で電子部品９０の一側面と主面の一部に外部電極９１を形成する。次に、電子部品９０を１８０度反転させ、（ｂ）のように２回目の転写で電子部品９０の他側面と主面の一部に外部電極９２を形成する。次に、（ｃ）のように表側の主面にマスキング９３を行い、スパッタリングにより外部電極９４を形成する。この時、外部電極９４の両端部が既に転写法で形成された外部電極９１，９２と接続されるように位置合わせを行う。さらに、電子部品９０を１８０度反転させ、（ｄ）のように電子部品９０の裏側の主面にマスキング９５を行い、スパッタリングにより外部電極９６を形成する。この時、外部電極９６の両端部が外部電極９１，９２と接続されるように位置合わせを行う。
【０００６】
この方法であれば、スパッタリングの回数を２回分削減できるが、それでも工程数が多く、また転写装置とスパッタ装置という２種類の装置を必要とするので、コスト上昇を招く。さらに、外部電極の側面は厚膜電極、表裏主面は薄膜電極というように厚みの異なる２種類の電極で構成されるため、電極強度に差を生じ、信頼性の低下を招く場合があった。
【０００７】
そこで、本発明の目的は、工程数が少なく、簡易な装置で鉢巻き状の電極を簡単に形成できる電子部品の電極形成方法を提供することにある。
【０００８】
【課題を解決するための手段】
上記目的を達成するため、請求項１に係る発明は、表裏対向する第１と第２の主面を有する電子部品の外周面に、鉢巻き状に周回する電極を形成する方法であって、弾性を持つ第１の転写版の表面に設けられた凹溝に第１の導電ペーストを充填する工程と、上記電子部品の第２の主面を粘着性を有する第１の保持治具で密着保持した状態で、電子部品の第１の主面を第１の転写版の表面に押し付け、電子部品の第１の主面およびこの主面に連なる２つの側面に第１の導電ペーストを回り込ませて転写する工程と、上記電子部品の第１の主面およびこの主面に連なる２つの側面に付着した第１の導電ペーストを乾燥させる工程と、弾性を持つ第２の転写版の表面に設けられた凹溝に第２の導電ペーストを充填する工程と、上記電子部品の第１の主面を粘着性を有する第２の保持治具で密着保持した状態で、電子部品の第２の主面を第２の転写版の表面に押し付け、電子部品の第２の主面およびこの主面に連なる２つの側面に第２の導電ペーストを回り込ませ、かつ側面に回り込んだ第２の導電ペーストが側面に形成された第１の導電ペーストと接続されるように転写する工程と、上記電子部品の第２の主面およびこの主面に連なる２つの側面に付着した第２の導電ペーストを乾燥させる工程と、上記乾燥後の第１，第２の導電ペーストを焼き付けて電極とする工程と、を有し、上記第１の保持治具は、上記第１の転写版の凹溝と直交する方向に延び、かつ上記電子部品の凹溝方向の幅寸法より狭い幅寸法の凸部を持ち、この凸部の表面が上記電子部品の第２の主面の幅方向中央部を密着保持する粘着性を持ち、上記第２の保持治具は、上記第２の転写版の凹溝と直交する方向に延び、かつ上記電子部品の凹溝方向の幅寸法より狭い幅寸法の凸部を持ち、この凸部の表面が上記電子部品の第１の主面の幅方向中央部を密着保持する粘着性を持つことを特徴とする電子部品の電極形成方法を提供する。
【０００９】
まず電子部品の第１の主面を第１の転写版に押し付け、凹溝に充填された第１の導電ペーストを電子部品に転写する。電子部品を転写版に押し付けた時、電子部品は転写版に対して沈み込み、導電ペーストは電子部品の第１の主面だけでなくこれと連なる２つの側面にも回り込む。この導電ペーストを乾燥させると、電子部品の３面に連続する帯状の電極が形成される。次に、電子部品を１８０度反転させ、第２の主面を第２の転写版に押し付け、凹溝に充填された第２の導電ペーストを電子部品に転写する。この時も１回目の転写と同様に、導電ペーストを電子部品の第２の主面およびこれと連なる２つの側面に回り込ませる。特に、第２の導電ペーストを回り込ませた時、側面に回り込んだ第２の導電ペーストが既に側面に塗布されている第１の導電ペーストと接続されるように、位置および沈み込み量を調整する。
このように２回の転写を実施するだけで、電子部品の周囲に鉢巻き状に周回する電極を形成することができる。しかも、外部電極はすべて転写法により形成される厚膜電極であるから、信頼性の低下を招くことがない。
【００１０】
本発明の電子部品としては、平板状の部品が望ましい。つまり、表裏主面の縦横の寸法に比べて、厚みが薄く、特に厚みが１ｍｍ以下であるような薄型部品が望ましい。その理由は、電子部品の主面を凹溝を有する転写版に押しつけた際、転写版が撓んで電子部品は若干沈み込むが、比較的少ない沈み込み量でも、電子部品の側面に厚みの１／２を越える電極の回り込みを形成できるからである。
電子部品の第１の主面に形成される電極と第２の主面に形成される電極とは同一位置、同一幅である必要はない。この場合には、側面に形成される電極が階段状や屈曲形状となる。
【００１１】
本発明では、電子部品の第２の主面を粘着性を有する第１の保持治具の表面で密着保持した状態で、電子部品の第１の主面を第１の転写版の表面に押し付けるとともに、電子部品の第１の主面を粘着性を有する第２の保持治具の表面で密着保持した状態で、電子部品の第２の主面を第２の転写版の表面に押し付けるものである。
例えば特公昭６２−２０６８５号公報に記載された保持具を用い、この保持具の穴に電子部品を保持して転写版に押しつけると、電子部品が転写版に対して沈み込むので、保持具の表面と転写版の表面とが接近し、導電ペーストが電子部品の側面まで回り込むだけでなく、保持具の表面にも付着してしまうことがある。
これに対し、電子部品の背面側を粘着性を有する保持治具で密着保持すれば、電子部品が多少沈み込んでも、転写版の表面と保持治具の表面との距離を確保できるので、保持治具に導電ペーストが付着する恐れが少ない。
なお、表面に粘着性を有する保持治具としては、例えばシリコーンゴムのような低弾性材料または粘弾性材料を少なくとも表層部に持つ治具を使用できる。軟質シリコーンゴムの場合、１〜１０ｇ／ｍｍ程度の粘着力を有するので、小型部品であれば十分に保持できる。
さらに、本発明では、第１の保持治具は、第１の転写版の凹溝と直交する方向に延び、かつ電子部品の凹溝方向の幅寸法より狭い幅寸法の凸部を持ち、この凸部の表面が電子部品の第２の主面の幅方向中央部を密着保持する粘着性を持ち、第２の保持治具は、第２の転写版の凹溝と直交する方向に延び、かつ電子部品の凹溝方向の幅寸法より狭い幅寸法の凸部を持ち、この凸部の表面が電子部品の第１の主面の幅方向中央部を密着保持する粘着性を持つものである。電子部品の背面側を粘着性を有する保持治具で密着保持し、電子部品の主面を転写版に押しつけるので、保持治具に導電ペーストが付着する恐れが少ないが、強く押しつけた場合には側面に回り込んだ導電ペーストが保持治具に付着する可能性がある。本発明では、保持治具が電子部品の背面の幅方向中央部を密着保持する凸部を持つので、導電ペーストが保持治具に付着する可能性をさらに低くできる。
【００１２】
請求項３のように、第２の保持治具の粘着力を第１の保持治具の粘着力より大きくし、第１の保持治具に電子部品を保持したまま第１の導電ペーストを乾燥させた後、電子部品の第１の主面を第２の保持治具の表面に密着させ、電子部品を第１の保持治具から第２の保持治具に移し替えるようにするのが望ましい。
多数の電子部品に対し同時に電極を形成する場合には、１つの保持治具に多数の電子部品を密着保持させ、しかも個々の電子部品の位置を安定に保持する必要がある。しかし、１回目の転写と２回目の転写との間で電子部品を１８０度反転させる必要があるので、電子部品を第１の保持治具から一旦取り外してばらばらにした後、再度整列して第２の保持治具に密着保持させる方法では、作業が極めて煩雑になる。
そこで、請求項３では、第１の保持治具に電子部品を保持したまま導電ペーストを乾燥させ、導電ペーストが乾燥した電子部品の第１の主面を第２の保持治具の表面に密着させ、電子部品を第１の保持治具から第２の保持治具に移し替える。このとき、第２の保持治具の粘着力が第１の保持治具の粘着力より大きいので、電子部品は第１の保持治具から第２の保持治具に簡単に移り替わる。しかも、個々の電子部品の位置は第１の保持治具から第２の保持治具に移る間で変化しないので、位置精度に狂いが生じない。
このような移し替え方法を用いれば、多数の電子部品を効率よく、かつ精度よく反転させることができる。
【００１４】
【発明の実施の形態】
図１〜図３は本発明に係る製造方法により製造されたケース基板１を用いた表面実装型の圧電共振部品の一例を示す。
この圧電共振部品は、ケース基板１の上に短冊形の圧電素子１０を搭載し、ケース基板１の上に金属キャップ２０を接着することにより、圧電素子１０の周囲を封止した構造となっている。
【００１５】
ケース基板１は、圧電性を有しない誘電体セラミックスを複数層積層したものであり、全体として長方形板状に形成されている。ケース基板１の外表面には、図４，図５に示すように、入，出力電極となる第１，第２の外部電極２，３と、アース電極となる第３の外部電極４とが形成されている。これら外部電極２，３，４は厚膜電極である。第１，第２の外部電極２，３はケース基板１の上面，下面および両側面を鉢巻き状に周回する帯状電極であり、ケース基板１の上下面において幅方向に延びる上面電極２ａ，３ａおよび下面電極２ｂ，３ｂと、ケース基板１の両側面において厚み方向に延びる側面電極２ｃ，３ｃとを有している。ここでは、上面電極２ａ，３ａ、下面電極２ｂ，３ｂ、側面電極２ｃ，３ｃは互いに同一幅に形成されている。第３の外部電極４はケース基板１の下面から両側面の一部へ延びる帯状の電極であり、ケース基板１の上面側のみが欠落している。すなわち、第３の外部電極４は下面電極４ａと側面電極４ｂとで構成されている。
【００１６】
ケース基板１の内部には、図５に示すように複数の容量電極５〜９が形成されている。すなわち、ケース基板１は４層の誘電体層１ａ〜１ｄで構成されており、第１の層１ａには容量電極が形成されておらず、第２の層１ｂには２つに分割された容量電極５，６が形成され、第３の層１ｃには１つの広面積な容量電極７が形成され、第４の層１ｄには２つに分割された容量電極８，９が形成されている。容量電極５，６と容量電極８，９は同一形状である。容量電極５〜９の幅方向両端部には、ケース基板１の長辺側側面に露出する引出部５ａ〜９ａが形成され、引出部５ａ，８ａは第１の外部電極２の側面電極２ｃと接続され、引出部６ａ，９ａは第２の外部電極３の側面電極３ｃと接続されている。さらに、容量電極７の引出部７ａは第３の外部電極４の側面電極４ｂと接続されている。
したがって、図６に示すように、第２の層１ｂを間にして対向する容量電極５，６と容量電極７との間でコンデンサＣ１，Ｃ２が形成され、第３の層１ｃを間にして対向する容量電極８，９と容量電極７との間でコンデンサＣ３，Ｃ４が形成される。
【００１７】
この実施例では、ケース基板１を４層の誘電体層１ａ〜１ｄで構成し、その内部に３層の容量電極５〜９を形成したが、これに限るものではない。例えば、誘電体層を３層構造（容量電極を２層構造）としてもよいし、誘電体層を５層以上（容量電極を４層以上）としてもよく、位相補償特性に応じて決定すればよい。
【００１８】
この実施例の圧電素子１０は、図７に示されるように、エネルギー閉じ込め型厚み縦振動モードの高調波を利用した圧電共振子であって、細長い矩形板状の圧電セラミックスよりなる圧電体１１と、この圧電体１１の表裏両面に形成され、かつ圧電体１１の長さ方向の一端から略中央部まで延びる第１，第２の励振電極１２，１３と、圧電体１１の内部に形成され、圧電体１１の長さ方向の他端から略中央部まで延びる内部電極１４とを備えており、励振電極１２，１３と内部電極１４とは一部で対向している。圧電体１１の長さ方向両端面には端面電極１５，１６が形成され、一方の端面電極１５は励振電極１２，１３と接続され、他方の端面電極１６は内部電極１４と接続されている。なお、端面電極１６は、圧電体１１の表裏面まで一部回り込んでいる。
圧電体１１は図７に矢印Ｐで示すように厚み方向に分極されており、端面電極１５，１６間に所定の信号を入力することにより、スプリアスの少ない厚み縦振動の高調波を励振させることができる。
【００１９】
図１，図３に示すように、圧電素子１０はその長さ方向がケース基板１の長辺方向と平行になるように、ケース基板１上に配置され、端面電極１６，１５が、ケース基板１の上面電極２ａ，３ａにそれぞれ導電性接着剤や半田などの導電性接合材１７，１８によって電気的に接続され、かつ機械的に固定されている。なお、圧電素子１０の振動を阻害しないように、圧電素子１０の中央部とケース基板１との間には所定の隙間δが設けられている（図３参照）。
【００２０】
キャップ２０は金属板をプレス成形したものであり、その開口部には絶縁性の接着剤（図示せず）が転写などによって塗布される。ケース基板１の上に圧電素子１０が搭載された後、キャップ２０が圧電素子１０を覆うようにケース基板１の上面に接着固定される。接着剤としては、例えばエポキシ系などの熱硬化性接着剤を用いることができる。
なお、絶縁性接着剤で接着固定した後、導電性接着剤によってキャップ２０とアース電極４とを接続し、シールド構造としてもよい。
この実施例のキャップ２０は金属板をプレス成形したものであるが、樹脂製キャップあるいはセラミック製キャップを用いてもよい。
【００２１】
ここで、上記実施例におけるケース基板１の製造途中における各電極形状を図８に示す。
図８の（ａ）は、容量電極５〜９を形成した４層の誘電体層１ａ〜１ｄを積層し、焼成した状態を示す。ケース基板１の長辺側の側面には、容量電極５〜９の引出部５ａ〜９ａが露出している。
なお、引出部５ａ〜９ａを露出させるために、ケース基板１の側面を平面研磨してもよいし、後述する側面電極２ｃ，３ｃ，４ｂとの電気的導通性を高めるために、サンドブラストやバレル研磨などを用いてケース基板１の側面を粗面としてもよい。
図８の（ｂ）は、ケース基板１の下面から側面に亘って連続して下面電極２ｂ，３ｂ，４ａと側面電極部分２ｃ₂ ，３ｃ₂ ，４ｂとを形成し、側面電極部分２ｃ₂ ，３ｃ₂ ，４ｂによってケース基板１の側面に露出した容量電極５〜９の引出部５ａ〜９ａを覆った状態を示す。
図８の（ｃ）は、（ｂ）のように下面から側面に亘って連続した電極を形成したケース基板１を１８０度反転させ、（ｂ）とほぼ同様の方法を用いてケース基板１の上面から側面にわたって連続した電極２ａ，３ａおよび側面電極部分２ｃ₁ ，３ｃ₁ を形成した状態を示す。この際、側面電極部分２ｃ₁ ，３ｃ₁ と側面電極部分２ｃ₂ ，３ｃ₂ とを接合させることが重要である。
上記のようにして、鉢巻き状に周回する外部電極２，３を形成できると共に、下面から側面へと延びる外部電極４も同時に形成できる。
【００２２】
図９〜図１１は外部電極２，３，４の具体的な形成方法を示す。この方法は、本発明の前提となるものである。
図９は１回目の転写方法を示す。
図９の（ａ）は、上面に複数本の溝３１〜３３を有する第１の転写版３０の上方に、電極を形成していないケース基板１を配置した状態を示す。転写版３０はゴム弾性を有するものであり、溝３１〜３３には導電ペーストＳが転写版３０の表面とほぼ同一面となるように充填されている。具体的には、導電ペーストＳを転写版３０の表面に供給し、スキージングすることで簡単に充填できる。また、ケース基板１は第１の保持治具４０の下面に密着保持されている。第１の保持治具４０は、少なくとも表層部が粘着性を持つシリコーンゴムなどの弾性材料で構成されている。なお、第１の保持治具４０を弾性材料のみで形成する場合のほか、剛性を持つ芯材の表層部を弾性材料で被覆したものでもよい。
図９の（ｂ）は、第１の保持治具４０を降下させ、ケース基板１を転写版３０に押しつけた状態を示す。ケース基板１を押しつけることにより、転写版３０が撓み、ケース基板１は転写版３０に対して沈み込む。このとき、溝３１〜３３内のペーストＳの一部がケース基板１の下面に押されてケース基板１の側面に回り込む。保持治具４０はケース基板１の背面を密着保持しているに過ぎないので、保持治具４０と転写版３０との距離を確保でき、ペーストＳが保持治具４０に付着する恐れが少ない。
図９の（ｃ）は、第１の保持治具４０を上昇させ、ケース基板１を転写版３０から引き上げた状態を示し、ケース基板１の下面から側面に亘って連続的にペーストＳが塗布される。１回の転写が終了した転写版３０の溝３１〜３３にはペーストＳの残量が少なくなるので、次の塗布のために転写版３０の上面にペーストＳを供給し、スキージングすることで、図９の（ａ）の状態に復帰する。
図９の（ｃ）のように導電ペーストＳを塗布したケース基板１を保持治具４０に密着保持したまま、乾燥炉へ搬送し、導電ペーストＳを乾燥させる。
【００２３】
図１０は１回目の転写が終了したケース基板１を１８０度反転させる方法を示す。
図１０の（ａ）は、第１の保持治具４０に保持されたケース基板１に対し、第２の保持治具５０を対面させた状態を示す。第２の保持治具５０も第１の保持治具４０と同様に、その表面でケース基板１を密着保持するものであり、例えばシリコーンゴムなどの表面に粘着性を持つ弾性材料で構成されている。特に、第２の保持治具５０の粘着力は第１の保持治具１の粘着力より大きい。
図１０の（ｂ）は、第１の保持治具４０に保持されたケース基板１に対し、第２の保持治具５０を押しつけた状態を示す。この際、乾燥した導電ペースト３部分だけでなく、ケース基板１の導電ペーストＳが付着していない部分にも保持治具５０が密着するように押し付けるのがよい。
図１０の（ｃ）は、第２の保持治具５０を第１の保持治具４０から引き離した状態を示し、粘着力の差によってケース基板１は第１の保持治具４０から第２の保持治具５０へ移し替えられる。
なお、図１０では単一のケース基板１を保持治具４０から保持治具５０へ移し替える場合を示しているが、実際の製造に際しては、数百あるいは数千個のケース基板１が同時に移し替えられる。上記のような粘着力の差のある２種類の保持治具４０，５０を用いることで、多数個のケース基板１を一括して、かつ個々のケース基板１の位置や姿勢を変えずに、保持治具４０から保持治具５０へ反転させて移し替えることができる。
【００２４】
図１１は２回目の転写方法を示す。
図１１の（ａ）は、上記のように第２の保持治具５０に移し替えられたケース基板１を、上面に２本の溝６１，６２を有する第２の転写版６０の上方に配置した状態を示す。第２の転写版６０も第１の転写版３０と同様にゴム弾性を有するものであり、溝６１，６２には導電ペーストＳが転写版６０の表面とほぼ同一面となるように充填されている。ここで重要な点は、１回目の転写で塗布された外部電極２，３となる導電ペーストＳの位置が、溝６１，６２の位置と一致するように、保持治具５０を転写版６０に対して正確に位置決めすることである。
図１１の（ｂ）は、保持治具５０を降下させ、ケース基板１を転写版６０に押しつけた状態を示す。ケース基板１を押しつけることにより、転写版６０が撓み、溝６１，６２内のペーストＳの一部がケース基板１の下面に押されてケース基板１の側面に回り込む。そのため、ケース基板１の側面に回り込んだ導電ペーストＳは、１回目に塗布された導電ペーストＳの側面電極部分と接続される。
図１１の（ｃ）は、保持治具５０を上昇させ、ケース基板１を転写版６０から引き上げた状態を示す。この状態で、ケース基板１の上面，下面および両側面に鉢巻き状に周回するよう導電ペーストＳが塗布される。
図１１の（ｃ）のように導電ペーストＳを塗布したケース基板１を保持治具５０に密着保持したまま、乾燥炉へ搬送し、導電ペーストＳを乾燥させる。導電ペーストＳが乾燥した後、ケース基板１を保持治具５０から取り外し、焼成炉へ搬送して導電ペーストＳを焼き付ける。その結果、外部電極２〜４を有するケース基板１が完成する。
なお、半田付け性向上のため、外部電極２〜４の上に適宜メッキ処理などを施してもよい。
【００２５】
図１２は本発明にかかる保持治具の一例を示す。
上記実施例では平板状の保持治具４０，５０を使用したが、この保持治具７０は、表面に粘着性を有する凸部７１を持ち、この凸部７１で電子部品１の短辺方向中央部の背面を密着保持するものである。そのため、電子部品１を転写版に押しつけた時、保持治具７０の凸部７１以外の逃げ部７２と、転写版との距離を確保でき、導電ペーストＳが保持治具７０に付着するのを防止できる。
【００２６】
この場合、図１３，図１４に示すように、凸部７１を剛体よりなる芯材７３の表層部に粘着性を有する弾性体７４の被膜を形成した構成とすれば、電子部品１を転写版に押しつけた時の凸部７１の撓みを少なくでき、導電ペーストの付着防止効果が高くなる。
なお、凸部７１の断面形状を図１５のような台形形状としてもよい。
【００２７】
図１６は保持治具の参考例を示す。
この保持治具８０は、粘着性を有する平板部８１に、導電ペーストの塗布箇所に相当する部分に逃げ溝８２を設けたものである。この場合も、電子部品１を転写版に押しつけた時、保持治具８０の逃げ溝８２と転写版との距離を確保でき、導電ペーストＳが保持治具８０に付着するのを防止できる。
【００２８】
図１７はケース基板の第２実施例を示す。なお、第１実施例のケース基板１と同一部分には同一符号を付して重複説明を省略する。
第２実施例のケース基板１では、上面電極２ａ，３ａの間隔ｄ１を、下面電極２ｂ，３ｂの間隔ｄ２より狭くしたものである。その理由は、上面電極２ａ，３ａの間隔ｄ１はその上に搭載される電子部品素子（圧電素子）１０の長さに応じて、下面電極の間隔ｄ２はケース基板１を実装する回路基板などの電極パッドの間隔に応じて、それぞれ最適な寸法に設定するためである。この実施例では、側面電極２ｃ，３ｃが階段状に屈曲している。
【００２９】
図１８はケース基板の第３実施例を示す。なお、第１実施例のケース基板１と同一部分には同一符号を付して重複説明を省略する。
第３実施例のケース基板１では、上面電極２ａ，３ａの幅ｄ３を下面電極２ｂ，３ｂの幅ｄ４より広くしたものである。但し、上面電極２ａ，３ａの間隔ｄ１は下面電極２ｂ，３ｂの間隔ｄ２より狭い。
この場合には、第２実施例のケース基板と同様に、上面電極２ａ，３ａの間隔ｄ１と下面電極の間隔ｄ２をそれぞれ最適な寸法に設定できるとともに、ケース基板１の上面のキャップ接着部に、上面電極２ａ，３ａによる段差が少なくなり、キャップ２０の封止性が向上する利点がある。
【００３０】
上記各実施例では、ケース基板１の両端部に鉢巻き状に周回する外部電極２，３を形成し、中央部に下面と側面とに連続する外部電極４を形成したが、これに限るものではない。例えば、中央部の外部電極４を省略してもよいし、両端部と中央部とに３本の鉢巻き状電極を形成してもよい。その他、鉢巻き状電極の本数や形状は任意に変更できる。
また、ケース基板１として誘電体よりなる多層基板を用いたが、ガラスセラミック，ガラスエポキシ樹脂、耐熱性樹脂等で構成してもよい。したがって、容量を内蔵したケース基板に限るものではない。
さらに、ケース基板１の上に搭載される電子部品素子は、厚み縦振動モード以外の圧電素子でもよく、さらに圧電素子以外の電子部品素子であってもよい。
【００３１】
電子部品の主面を転写版に押し付ける際、電子部品を保持する保持具として、粘着性を有する表面を持つ保持治具を使用したが、この保持治具はシリコーンゴムのようにその素材自体が粘着性を持つものに限らず、粘着テープなどを用いてもよい。また、特公昭６２−２０６８５号公報に記載された保持穴を備えた保持治具を使用してもよく、電子部品を真空吸着する方式や、電子部品の外周面をチャックする方式の保持治具を使用してもよい。
【００３２】
また、電子部品を第１の保持治具から第２の保持治具に移し替えるために、第２の保持治具の粘着力を第１の保持治具の粘着力より大きくしたが、例えば第２の保持治具の粘着面積を第１の保持治具の粘着面積より大きくしてもよい。例えば、第１の保持治具を図１２、第２の保持治具を図１６のようにすれば、粘着面積に差ができ、移し替えが容易にできる。また、第１の保持治具の粘着面に貫通穴を形成し、移し替え時に裏からピンで押すことで移し替えを行ってもよい。さらに、シリコーンゴムではなく粘着テープを用いた場合には、加熱やＵＶ照射などで粘着力を低下させることで、第１の保持治具から第２の保持治具へ容易に移し替えを行うことができる。
【００３３】
本発明が対象とする電子部品としては、上記実施例のような電子部品のケース基板に限らず、積層セラミックコンデンサや、チップ抵抗、チップインダクタなどのチップ部品であってもよい。
【００３４】
【発明の効果】
以上の説明で明らかなように、本発明によれば、電子部品の第１の主面を第１の転写版に押し付け、電子部品の第１の主面とこれに連なる２つの側面に導電ペーストを回り込ませて転写した後、電子部品を１８０度反転させ、第２の主面を第２の転写版に押し付けて、電子部品の第２の主面とこれに連なる２つの側面に導電ペーストを回り込ませて転写し、側面に回り込んだ第２の導電ペーストを側面に塗布されている第１の導電ペーストと接続したものである。
このように２回の転写を実施するだけで、電子部品の周囲に鉢巻き状に周回する電極を形成することができる。そのため、工程数が少なく、しかも簡易な転写版を用いて鉢巻き状の電極を簡単に形成できる。
また、本発明では電子部品の背面を粘着性を持つ保持治具で保持しながら、電子部品の表面を転写版の表面に押し付けて導電ペーストを転写するとともに、保持治具に電子部品の背面の幅方向中央部を保持する凸状の粘着面を設けたので、導電ペーストが保持治具に付着する危険性が殆どなく、安定した電極形成が可能である。
【図面の簡単な説明】
【図１】本発明に係る製造方法により製造されたケース基板を用いた表面実装型電子部品の一例の斜視図である。
【図２】図１に示す電子部品の外観図であり、（ａ）は平面図、（ｂ）は正面図、（ｃ）は側面図である。
【図３】図２のＡ−Ａ線断面図である。
【図４】図１に示す電子部品に用いられるケース基板の斜視図である。
【図５】ケース基板の分解斜視図である。
【図６】図１に示す電子部品の回路図である。
【図７】図１に示す電子部品に搭載される圧電素子の斜視図である。
【図８】ケース基板の製造途中における電極形状を示す斜視図である。
【図９】本発明の前提となるケース基板の電極形成方法の第１段階を示す工程図である。
【図１０】本発明の前提となるケース基板の電極形成方法の第２段階を示す工程図である。
【図１１】本発明の前提となるケース基板の電極形成方法の第３段階を示す工程図である。
【図１２】本発明にかかる保持治具の第１実施例の斜視図である。
【図１３】図１２のＢ−Ｂ線断面図である。
【図１４】図１２のＣ−Ｃ線断面図である。
【図１５】図１２に示す保持治具の凸部の変形例である。
【図１６】保持治具の参考例の斜視図である。
【図１７】ケース基板の第２実施例の斜視図である。
【図１８】ケース基板の第３実施例の斜視図である。
【図１９】転写法とスパッタリング法とを併用した従来例の工程図である。
【符号の説明】
１ケース基板（電子部品）
２第１の外部電極
３第２の外部電極
１０圧電素子
２０キャップ
３０第１の転写版
３１〜３３凹溝
４０第１の保持治具
５０第２の保持治具
６０第２の転写版
６１，６２凹溝
７０保持治具
７１凸部
Ｓ導電ペースト[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an electrode forming method for an electronic component, and more particularly to an electrode forming method suitable for forming an external electrode in a surface mount electronic component.
[0002]
[Prior art]
In recent years, along with the miniaturization of circuits, surface mount type (chip type) electronic components are widely used instead of leaded components. As this type of surface-mounted electronic component, for example, as described in Japanese Patent Application Laid-Open No. 2000-286665, there is a piezoelectric resonant component in which a piezoelectric resonator is mounted on a substrate and a cap that covers the piezoelectric resonator is attached to the substrate. Proposed. Three external electrodes are formed on the outer surfaces of both ends and the center of the substrate, and the external electrodes on both ends circulate around the substrate in a headband shape. Further, the upper part of the central external electrode is lacking.
[0003]
[Problems to be solved by the invention]
In the electronic component having the above structure, a sputtering method is usually used to form a head-shaped external electrode on a substrate. However, in order to form electrodes on the four surfaces of the substrate, sputtering must be performed four times. In sputtering, since it is necessary to mask parts other than the electrode forming portion, the number of processes is large and the cost is increased.
[0004]
On the other hand, there is also a method of forming an external electrode using a transfer method. For example, Japanese Patent Laid-Open No. 2-333908 proposes a method in which the side edge of an electronic component is pressed against the surface of a transfer plate in which a concave groove is filled with a conductive paste, and the conductive paste is simultaneously transferred to three surfaces of the component. . However, although this method can form electrodes on the side edges of electronic components, it cannot form electrodes that circulate in a headband shape.
[0005]
Accordingly, FIG. 19 shows an example of a method for forming a headband electrode by using both the transfer method and the sputtering method.
As shown in FIG. 19A, external electrodes 91 are formed on one side and a part of the main surface of the electronic component 90 by the first transfer. Next, the electronic component 90 is inverted 180 degrees, and external electrodes 92 are formed on the other side surface and a part of the main surface of the electronic component 90 by the second transfer as shown in FIG. Next, as shown in (c), masking 93 is performed on the main surface on the front side, and external electrodes 94 are formed by sputtering. At this time, alignment is performed so that both ends of the external electrode 94 are connected to the external electrodes 91 and 92 already formed by the transfer method. Further, the electronic component 90 is inverted 180 degrees, masking 95 is performed on the main surface on the back side of the electronic component 90 as shown in (d), and the external electrode 96 is formed by sputtering. At this time, alignment is performed so that both ends of the external electrode 96 are connected to the external electrodes 91 and 92.
[0006]
With this method, the number of times of sputtering can be reduced by two times. However, the number of processes is still large, and two kinds of devices, that is, a transfer device and a sputtering device, are required, resulting in an increase in cost. Furthermore, since the external electrode is composed of two types of electrodes having different thicknesses such as a thick film electrode on the side surface and a thin film electrode on the front and back surfaces, there may be a difference in electrode strength, leading to a decrease in reliability. .
[0007]
SUMMARY OF THE INVENTION An object of the present invention is to provide an electrode forming method for an electronic component that can easily form a headband-shaped electrode with a simple apparatus with a small number of steps.
[0008]
[Means for Solving the Problems]
In order to achieve the above object, the invention according to claim 1 is a method of forming an electrode that circulates in a headband shape on an outer peripheral surface of an electronic component having first and second main surfaces facing each other, and is elastic. Filling the first conductive paste into the grooves provided on the surface of the first transfer plate havingIn a state where the second main surface of the electronic component is tightly held by the first holding jig having adhesiveness,A step of pressing the first main surface of the electronic component against the surface of the first transfer plate and transferring the first conductive paste around the first main surface of the electronic component and the two side surfaces connected to the main surface; ,Adhered to the first main surface of the electronic component and two side surfaces connected to the main surfaceA step of drying the first conductive paste, a step of filling the concave groove provided on the surface of the elastic second transfer plate with the second conductive paste,In a state where the first main surface of the electronic component is closely held by a second holding jig having adhesiveness,The second main surface of the electronic component is pressed against the surface of the second transfer plate, and the second conductive paste is wrapped around the second main surface of the electronic component and the two side surfaces connected to the main surface. Transferring the inserted second conductive paste to be connected to the first conductive paste formed on the side surface;Adhered to the second main surface of the electronic component and two side surfaces connected to the main surfaceDrying the second conductive paste;After dryingAnd baking the first and second conductive pastes to form electrodes.The first holding jig has a convex portion extending in a direction orthogonal to the concave groove of the first transfer plate and having a width smaller than the width of the electronic component in the concave groove direction. The surface of the part has an adhesive property that tightly holds the central part in the width direction of the second main surface of the electronic component, and the second holding jig is in a direction perpendicular to the concave groove of the second transfer plate. It has a convex portion that extends and has a width dimension narrower than the width dimension in the groove direction of the electronic component, and the surface of the convex portion has an adhesive property that tightly holds the central portion in the width direction of the first main surface of the electronic component. It is characterized by havingProvided is an electrode forming method for an electronic component.
[0009]
First, the first main surface of the electronic component is pressed against the first transfer plate, and the first conductive paste filled in the groove is transferred to the electronic component. When the electronic component is pressed against the transfer plate, the electronic component sinks into the transfer plate, and the conductive paste goes around not only the first main surface of the electronic component but also the two side surfaces that are connected to it. When this conductive paste is dried, strip-shaped electrodes that are continuous on the three surfaces of the electronic component are formed. Next, the electronic component is inverted 180 degrees, the second main surface is pressed against the second transfer plate, and the second conductive paste filled in the concave grooves is transferred to the electronic component. At this time, similarly to the first transfer, the conductive paste is made to wrap around the second main surface of the electronic component and the two side surfaces connected to the second main surface. In particular, when the second conductive paste wraps around, the position and sinking amount are adjusted so that the second conductive paste wrapping around the side surface is connected to the first conductive paste already applied to the side surface. To do.
In this way, an electrode that circulates in a headband shape can be formed around the electronic component only by performing the transfer twice. In addition, since all the external electrodes are thick film electrodes formed by a transfer method, reliability is not lowered.
[0010]
As the electronic component of the present invention, a plate-shaped component is desirable. That is, it is desirable to use a thin part having a thickness that is smaller than the vertical and horizontal dimensions of the front and back main surfaces, and particularly a thickness of 1 mm or less. The reason is that when the main surface of the electronic component is pressed against a transfer plate having a concave groove, the transfer plate bends and the electronic component sinks slightly, but even with a relatively small amount of sinking, the thickness of the electronic component is reduced to 1 side. This is because the wraparound of the electrode exceeding / 2 can be formed.
The electrode formed on the first main surface of the electronic component and the electrode formed on the second main surface need not be at the same position and the same width. In this case, the electrodes formed on the side surfaces are stepped or bent.
[0011]
In the present inventionThe second main surface of the electronic component is pressed and held against the surface of the first transfer plate while the second main surface of the electronic component is held in close contact with the surface of the first holding jig having adhesiveness. The second main surface of the electronic component is pressed against the surface of the second transfer plate in a state where the first main surface of the component is tightly held by the surface of the second holding jig having adhesiveness.Is.
For example, when a holder described in Japanese Patent Publication No. 62-20585 is used and an electronic component is held in the hole of the holder and pressed against the transfer plate, the electronic component sinks into the transfer plate. The surface and the surface of the transfer plate are close to each other, and the conductive paste may not only go around to the side surface of the electronic component but also adhere to the surface of the holder.
On the other hand, if the back side of the electronic component is closely held with an adhesive holding jig, the distance between the surface of the transfer plate and the surface of the holding jig can be secured even if the electronic component sinks somewhat. There is little risk of conductive paste adhering to the jig.
In addition, as a holding jig having adhesiveness on the surface, for example, a jig having at least a surface layer portion of a low elastic material or a viscoelastic material such as silicone rubber can be used. In the case of soft silicone rubber, since it has an adhesive force of about 1 to 10 g / mm, a small component can be sufficiently retained.
Furthermore, in the present invention, the first holding jig has a convex portion extending in a direction orthogonal to the concave groove of the first transfer plate and having a width dimension narrower than the width dimension in the concave groove direction of the electronic component. The surface of the convex portion has an adhesive property that tightly holds the central portion in the width direction of the second main surface of the electronic component, and the second holding jig extends in a direction perpendicular to the concave groove of the second transfer plate, And it has the convex part of the width dimension narrower than the width dimension of the groove direction of an electronic component, and the surface of this convex part has the adhesiveness which closely_contact | adheres the width direction center part of the 1st main surface of an electronic component. . The back side of the electronic component is held in close contact with an adhesive holding jig and the main surface of the electronic component is pressed against the transfer plate, so there is little risk of conductive paste adhering to the holding jig. There is a possibility that the conductive paste that wraps around the side surface adheres to the holding jig. In the present invention, since the holding jig has a convex portion that closely holds the central portion in the width direction of the back surface of the electronic component, the possibility that the conductive paste adheres to the holding jig can be further reduced.
[0012]
As in claim 3, the adhesive force of the second holding jig is made larger than the adhesive force of the first holding jig, and the first conductive paste is dried while holding the electronic component on the first holding jig. Then, it is desirable that the first main surface of the electronic component is brought into close contact with the surface of the second holding jig, and the electronic component is transferred from the first holding jig to the second holding jig. .
When electrodes are formed simultaneously on a large number of electronic components, it is necessary to hold a large number of electronic components in close contact with one holding jig and to hold the positions of the individual electronic components stably. However, since it is necessary to reverse the electronic component by 180 degrees between the first transfer and the second transfer, the electronic component is once detached from the first holding jig and separated, and then aligned again. In the method of tightly holding the two holding jigs, the operation becomes extremely complicated.
Accordingly, in claim 3, the conductive paste is dried while the electronic component is held on the first holding jig, and the first main surface of the electronic component on which the conductive paste is dried is in close contact with the surface of the second holding jig. The electronic component is transferred from the first holding jig to the second holding jig. At this time, since the adhesive force of the second holding jig is larger than the adhesive force of the first holding jig, the electronic component is easily transferred from the first holding jig to the second holding jig. In addition, since the position of each electronic component does not change during the transition from the first holding jig to the second holding jig, there is no deviation in position accuracy.
If such a transfer method is used, a large number of electronic components can be reversed efficiently and accurately.
[0014]
DETAILED DESCRIPTION OF THE INVENTION
1 to 3 show an example of a surface-mount type piezoelectric resonant component using a case substrate 1 manufactured by the manufacturing method according to the present invention.
The piezoelectric resonant component has a structure in which a rectangular piezoelectric element 10 is mounted on a case substrate 1 and a metal cap 20 is bonded on the case substrate 1 to seal the periphery of the piezoelectric element 10. Yes.
[0015]
The case substrate 1 is formed by laminating a plurality of dielectric ceramics having no piezoelectricity, and is formed in a rectangular plate shape as a whole. On the outer surface of the case substrate 1, as shown in FIGS. 4 and 5, first and second external electrodes 2 and 3 serving as input and output electrodes and a third external electrode 4 serving as a ground electrode are provided. Is formed. These external electrodes 2, 3 and 4 are thick film electrodes. The first and second external electrodes 2 and 3 are belt-like electrodes that wrap around the upper surface, lower surface, and both side surfaces of the case substrate 1 in a headband shape, and upper surface electrodes 2a and 3a extending in the width direction on the upper and lower surfaces of the case substrate 1; Lower surface electrodes 2b and 3b and side surface electrodes 2c and 3c extending in the thickness direction on both side surfaces of the case substrate 1 are provided. Here, the upper surface electrodes 2a and 3a, the lower surface electrodes 2b and 3b, and the side surface electrodes 2c and 3c are formed to have the same width. The third external electrode 4 is a belt-like electrode extending from the lower surface of the case substrate 1 to a part of both side surfaces, and only the upper surface side of the case substrate 1 is missing. That is, the third external electrode 4 is composed of the lower surface electrode 4a and the side surface electrode 4b.
[0016]
Inside the case substrate 1, a plurality of capacitive electrodes 5 to 9 are formed as shown in FIG. That is, the case substrate 1 is composed of four dielectric layers 1a to 1d. No capacitance electrode is formed on the first layer 1a, and the second layer 1b is divided into two. Capacitance electrodes 5 and 6 are formed, one large-area capacitance electrode 7 is formed on the third layer 1c, and two divided capacitance electrodes 8 and 9 are formed on the fourth layer 1d. Yes. The capacitive electrodes 5 and 6 and the capacitive electrodes 8 and 9 have the same shape. At both ends in the width direction of the capacitive electrodes 5 to 9, lead portions 5 a to 9 a exposed on the long side surface of the case substrate 1 are formed, and the lead portions 5 a and 8 a are connected to the side electrode 2 c of the first external electrode 2. The lead portions 6 a and 9 a are connected to the side electrode 3 c of the second external electrode 3. Further, the lead portion 7 a of the capacitive electrode 7 is connected to the side electrode 4 b of the third external electrode 4.
Therefore, as shown in FIG. 6, capacitors C1 and C2 are formed between the capacitive electrodes 5 and 6 and the capacitive electrode 7 facing each other with the second layer 1b in between, and the third layer 1c in between. Capacitors C3 and C4 are formed between the capacitor electrodes 8 and 9 and the capacitor electrode 7 facing each other.
[0017]
In this embodiment, the case substrate 1 is composed of four dielectric layers 1a to 1d, and the three capacitive electrodes 5 to 9 are formed therein. However, the present invention is not limited to this. For example, the dielectric layer may have a three-layer structure (capacitance electrode has a two-layer structure), the dielectric layer may have five or more layers (capacitance electrode has four or more layers), and may be determined according to phase compensation characteristics. Good.
[0018]
As shown in FIG. 7, the piezoelectric element 10 of this embodiment is a piezoelectric resonator using harmonics of an energy confinement type thickness longitudinal vibration mode, and includes a piezoelectric body 11 made of an elongated rectangular plate-shaped piezoelectric ceramic, The first and second excitation electrodes 12 and 13 are formed on both the front and back surfaces of the piezoelectric body 11 and extend from one end in the longitudinal direction of the piezoelectric body 11 to a substantially central portion, and the piezoelectric body 11 is formed inside. An internal electrode 14 extending from the other end in the length direction of the piezoelectric body 11 to a substantially central portion is provided, and the excitation electrodes 12 and 13 and the internal electrode 14 are partially opposed to each other. End face electrodes 15 and 16 are formed on both longitudinal end faces of the piezoelectric body 11, one end face electrode 15 is connected to the excitation electrodes 12 and 13, and the other end face electrode 16 is connected to the internal electrode 14. Note that the end face electrode 16 partially wraps up to the front and back surfaces of the piezoelectric body 11.
The piezoelectric body 11 is polarized in the thickness direction as indicated by an arrow P in FIG. 7, and a predetermined signal is input between the end face electrodes 15 and 16 to excite harmonics of thickness longitudinal vibration with less spurious. Can do.
[0019]
As shown in FIGS. 1 and 3, the piezoelectric element 10 is arranged on the case substrate 1 so that the length direction thereof is parallel to the long side direction of the case substrate 1, and the end face electrodes 16 and 15 are arranged on the case substrate. The upper surface electrodes 2a and 3a are electrically connected to each other by conductive bonding materials 17 and 18 such as a conductive adhesive and solder, and are mechanically fixed. A predetermined gap δ is provided between the central portion of the piezoelectric element 10 and the case substrate 1 so as not to hinder the vibration of the piezoelectric element 10 (see FIG. 3).
[0020]
The cap 20 is formed by press-molding a metal plate, and an insulating adhesive (not shown) is applied to the opening by transfer or the like. After the piezoelectric element 10 is mounted on the case substrate 1, the cap 20 is bonded and fixed to the upper surface of the case substrate 1 so as to cover the piezoelectric element 10. As the adhesive, for example, an epoxy-based thermosetting adhesive can be used.
In addition, after adhering and fixing with an insulating adhesive, the cap 20 and the ground electrode 4 may be connected with a conductive adhesive to form a shield structure.
The cap 20 in this embodiment is formed by press-molding a metal plate, but a resin cap or a ceramic cap may be used.
[0021]
Here, each electrode shape in the middle of manufacture of the case board | substrate 1 in the said Example is shown in FIG.
(A) of FIG. 8 shows the state which laminated | stacked and baked four dielectric layers 1a-1d in which the capacitive electrodes 5-9 were formed. The lead portions 5 a to 9 a of the capacitive electrodes 5 to 9 are exposed on the side surface on the long side of the case substrate 1.
In order to expose the lead portions 5a to 9a, the side surface of the case substrate 1 may be planarly polished, or in order to improve electrical conductivity with side electrodes 2c, 3c, 4b described later, The side surface of the case substrate 1 may be roughened by polishing or the like.
(B) of FIG. 8 shows the lower surface electrodes 2b, 3b, 4a and the side surface electrode portion 2c continuously from the lower surface to the side surface of the case substrate 1.₂ , 3c₂ , 4b and the side electrode portion 2c₂ , 3c₂ , 4b show the state where the lead portions 5a-9a of the capacitive electrodes 5-9 exposed on the side surface of the case substrate 1 are covered.
8C, the case substrate 1 formed with the continuous electrode from the bottom surface to the side surface as shown in FIG. 8B is inverted 180 degrees, and the case substrate 1 is formed by using a method substantially the same as that in FIG. Electrodes 2a and 3a and side electrode portion 2c continuous from the upper surface to the side surface₁ , 3c₁ The state which formed is shown. At this time, the side electrode portion 2c₁ , 3c₁ And side electrode part 2c₂ , 3c₂ It is important to join the two.
As described above, the external electrodes 2 and 3 that circulate in a headband shape can be formed, and the external electrode 4 extending from the lower surface to the side surface can be formed at the same time.
[0022]
9 to 11 show a specific method for forming the external electrodes 2, 3 and 4.This method is a premise of the present invention.
FIG. 9 shows the first transfer method.
FIG. 9A shows a state in which the case substrate 1 on which no electrode is formed is disposed above the first transfer plate 30 having a plurality of grooves 31 to 33 on the upper surface. The transfer plate 30 has rubber elasticity, and the grooves 31 to 33 are filled with the conductive paste S so as to be substantially flush with the surface of the transfer plate 30. Specifically, the conductive paste S can be easily filled by supplying to the surface of the transfer plate 30 and squeezing. The case substrate 1 is held in close contact with the lower surface of the first holding jig 40. The first holding jig 40 is made of an elastic material such as silicone rubber having at least a surface layer having adhesiveness. In addition to the case where the first holding jig 40 is formed of only an elastic material, the surface layer of a rigid core material may be covered with an elastic material.
FIG. 9B shows a state in which the first holding jig 40 is lowered and the case substrate 1 is pressed against the transfer plate 30. By pressing the case substrate 1, the transfer plate 30 is bent, and the case substrate 1 sinks into the transfer plate 30. At this time, a part of the paste S in the grooves 31 to 33 is pushed by the lower surface of the case substrate 1 and goes around the side surface of the case substrate 1. Since the holding jig 40 merely holds the back surface of the case substrate 1 in close contact, the distance between the holding jig 40 and the transfer plate 30 can be secured, and there is little possibility that the paste S adheres to the holding jig 40.
FIG. 9C shows a state in which the first holding jig 40 is raised and the case substrate 1 is pulled up from the transfer plate 30, and the paste S is continuously applied from the lower surface to the side surface of the case substrate 1. Is done. Since the remaining amount of the paste S is reduced in the grooves 31 to 33 of the transfer plate 30 after one transfer, the paste S is supplied to the upper surface of the transfer plate 30 and squeezed for the next application. 9 returns to the state shown in FIG.
As shown in FIG. 9C, the case substrate 1 coated with the conductive paste S is transported to a drying furnace while being closely held by the holding jig 40, and the conductive paste S is dried.
[0023]
FIG. 10 shows a method of reversing the case substrate 1 after the first transfer by 180 degrees.
FIG. 10A shows a state in which the second holding jig 50 faces the case substrate 1 held by the first holding jig 40. Similar to the first holding jig 40, the second holding jig 50 also holds the case substrate 1 in close contact with its surface, and is made of an elastic material having adhesiveness on the surface, such as silicone rubber. Yes. In particular, the adhesive strength of the second holding jig 50 is greater than the adhesive strength of the first holding jig 1.
FIG. 10B shows a state where the second holding jig 50 is pressed against the case substrate 1 held by the first holding jig 40. At this time, it is preferable to press the holding jig 50 not only to the dry conductive paste 3 portion but also to the portion of the case substrate 1 where the conductive paste S is not attached.
FIG. 10C shows a state in which the second holding jig 50 is separated from the first holding jig 40, and the case substrate 1 is moved from the first holding jig 40 to the second by the difference in adhesive force. It is transferred to the holding jig 50.
FIG. 10 shows the case where the single case substrate 1 is transferred from the holding jig 40 to the holding jig 50. However, in actual manufacturing, hundreds or thousands of case substrates 1 are transferred simultaneously. Be replaced. By using the two types of holding jigs 40 and 50 having a difference in adhesive force as described above, a large number of case substrates 1 can be collectively and without changing the position and posture of each case substrate 1. The holding jig 40 can be inverted and transferred from the holding jig 40.
[0024]
FIG. 11 shows a second transfer method.
In FIG. 11A, the case substrate 1 transferred to the second holding jig 50 as described above is disposed above the second transfer plate 60 having two grooves 61 and 62 on the upper surface. Shows the state. Similarly to the first transfer plate 30, the second transfer plate 60 has rubber elasticity, and the grooves 61 and 62 are filled with the conductive paste S so as to be substantially flush with the surface of the transfer plate 60. Yes. The important point here is that the holding jig 50 is placed on the transfer plate 60 so that the position of the conductive paste S to be the external electrodes 2 and 3 applied in the first transfer coincides with the positions of the grooves 61 and 62. It is to position correctly with respect to it.
FIG. 11B shows a state where the holding jig 50 is lowered and the case substrate 1 is pressed against the transfer plate 60. By pressing the case substrate 1, the transfer plate 60 is bent, and a part of the paste S in the grooves 61 and 62 is pressed against the lower surface of the case substrate 1 and goes around the side surface of the case substrate 1. Therefore, the conductive paste S that wraps around the side surface of the case substrate 1 is connected to the side electrode portion of the conductive paste S applied for the first time.
FIG. 11C shows a state where the holding jig 50 is raised and the case substrate 1 is pulled up from the transfer plate 60. In this state, the conductive paste S is applied to the upper surface, the lower surface and both side surfaces of the case substrate 1 so as to circulate in a headband shape.
As shown in FIG. 11C, the case substrate 1 coated with the conductive paste S is conveyed to a drying furnace while being held in close contact with the holding jig 50, and the conductive paste S is dried. After the conductive paste S is dried, the case substrate 1 is removed from the holding jig 50 and conveyed to a baking furnace, and the conductive paste S is baked. As a result, the case substrate 1 having the external electrodes 2 to 4 is completed.
In order to improve solderability, the external electrodes 2 to 4 may be appropriately plated.
[0025]
FIG.An example of a holding jig according to the present inventionIndicates.
In the above embodiment, the flat holding jigs 40 and 50 are used. However, the holding jig 70 has a convex portion 71 having adhesiveness on the surface, and the central portion of the electronic component 1 in the short side direction by the convex portion 71. The back surface of the part is held in close contact. Therefore, when the electronic component 1 is pressed against the transfer plate, a distance between the transfer plate 72 other than the convex portion 71 of the holding jig 70 and the transfer plate can be secured, and the conductive paste S adheres to the holding jig 70. Can be prevented.
[0026]
In this case, as shown in FIG. 13 and FIG. 14, if the convex portion 71 has a structure in which a coating of an elastic body 74 having adhesiveness is formed on the surface layer portion of a core 73 made of a rigid body, the electronic component 1 is transferred to a transfer plate. The bending of the convex part 71 when pressed against can be reduced, and the effect of preventing the adhesion of the conductive paste is enhanced.
The cross-sectional shape of the convex portion 71 may be a trapezoidal shape as shown in FIG.
[0027]
Figure 16 shows the holding jigReference exampleIndicates.
This holding jig 80 is formed by providing a relief groove 82 in a portion corresponding to a location where the conductive paste is applied to a flat plate portion 81 having adhesiveness. Also in this case, when the electronic component 1 is pressed against the transfer plate, the distance between the escape groove 82 of the holding jig 80 and the transfer plate can be secured, and the conductive paste S can be prevented from adhering to the holding jig 80.
[0028]
FIG. 17 shows a second embodiment of the case substrate. In addition, the same code | symbol is attached | subjected to the same part as the case board | substrate 1 of 1st Example, and duplication description is abbreviate | omitted.
In the case substrate 1 of the second embodiment, the distance d1 between the upper surface electrodes 2a and 3a is made smaller than the distance d2 between the lower surface electrodes 2b and 3b. The reason is that the distance d1 between the upper surface electrodes 2a and 3a depends on the length of the electronic component element (piezoelectric element) 10 mounted thereon, and the distance d2 between the lower surface electrodes is such as a circuit board on which the case substrate 1 is mounted. This is because the optimum dimensions are set according to the distance between the electrode pads. In this embodiment, the side electrodes 2c and 3c are bent stepwise.
[0029]
FIG. 18 shows a third embodiment of the case substrate. In addition, the same code | symbol is attached | subjected to the same part as the case board | substrate 1 of 1st Example, and duplication description is abbreviate | omitted.
In the case substrate 1 of the third embodiment, the width d3 of the upper surface electrodes 2a and 3a is made wider than the width d4 of the lower surface electrodes 2b and 3b. However, the distance d1 between the upper surface electrodes 2a and 3a is narrower than the distance d2 between the lower surface electrodes 2b and 3b.
In this case, similarly to the case substrate of the second embodiment, the distance d1 between the upper surface electrodes 2a and 3a and the distance d2 between the lower surface electrodes can be set to optimum dimensions, respectively, and at the cap adhesive portion on the upper surface of the case substrate 1 The steps due to the upper surface electrodes 2a and 3a are reduced, and there is an advantage that the sealing performance of the cap 20 is improved.
[0030]
In each of the above embodiments, the external electrodes 2 and 3 that circulate in a bowl shape are formed at both ends of the case substrate 1, and the external electrode 4 that is continuous to the lower surface and the side surface is formed at the central portion. Absent. For example, the central external electrode 4 may be omitted, or three headband electrodes may be formed at both ends and the central part. In addition, the number and shape of the headband electrodes can be arbitrarily changed.
Further, although a multilayer substrate made of a dielectric is used as the case substrate 1, it may be made of glass ceramic, glass epoxy resin, heat resistant resin, or the like. Therefore, the present invention is not limited to the case substrate with a built-in capacitor.
Furthermore, the electronic component element mounted on the case substrate 1 may be a piezoelectric element other than the thickness longitudinal vibration mode, and may be an electronic component element other than the piezoelectric element.
[0031]
When pressing the main surface of the electronic component against the transfer plate, a holding jig with an adhesive surface was used as a holding tool to hold the electronic component. This holding jig is made of a material such as silicone rubber. It is not limited to those having adhesiveness, and an adhesive tape or the like may be used. Also, a holding jig having a holding hole described in Japanese Patent Publication No. 62-20585 may be used, and a holding jig of a method for vacuum-sucking an electronic component or a method of chucking an outer peripheral surface of an electronic component. May be used.
[0032]
Further, in order to transfer the electronic component from the first holding jig to the second holding jig, the adhesive force of the second holding jig is made larger than the adhesive force of the first holding jig. The adhesive area of the second holding jig may be larger than the adhesive area of the first holding jig. For example, if the first holding jig is as shown in FIG. 12 and the second holding jig is as shown in FIG. 16, the adhesive area can be different and transfer can be facilitated. Further, the transfer may be performed by forming a through hole in the adhesive surface of the first holding jig and pressing it with a pin from the back during the transfer. Furthermore, when adhesive tape is used instead of silicone rubber, transfer from the first holding jig to the second holding jig can be easily performed by reducing the adhesive strength by heating or UV irradiation. Can do.
[0033]
The electronic component targeted by the present invention is not limited to the case substrate of the electronic component as in the above embodiment, and may be a chip component such as a multilayer ceramic capacitor, a chip resistor, or a chip inductor.
[0034]
【The invention's effect】
As is apparent from the above description, according to the present invention, the first main surface of the electronic component is pressed against the first transfer plate, and the first main surface of the electronic component and the two side surfaces connected to the first main surface are electrically conductive paste. , The electronic component is inverted 180 degrees, the second main surface is pressed against the second transfer plate, and the conductive paste is applied to the second main surface of the electronic component and the two side surfaces connected to the second main surface. The second conductive paste that has been transferred around and transferred to the side surface is connected to the first conductive paste applied to the side surface.
In this way, an electrode that circulates in a headband shape can be formed around the electronic component only by performing the transfer twice. Therefore, it is possible to easily form a headband-shaped electrode using a simple transfer plate with a small number of steps.
In the present invention, while holding the back surface of the electronic component with an adhesive holding jig, the surface of the electronic component is pressed against the surface of the transfer plate to transfer the conductive paste, and the back surface of the electronic component is transferred to the holding jig. Since the convex adhesive surface that holds the central portion in the width direction is provided, there is almost no risk of the conductive paste adhering to the holding jig, and stable electrode formation is possible.
[Brief description of the drawings]
FIG. 1 is a perspective view of an example of a surface mount electronic component using a case substrate manufactured by a manufacturing method according to the present invention.
2 is an external view of the electronic component shown in FIG. 1, wherein (a) is a plan view, (b) is a front view, and (c) is a side view. FIG.
FIG. 3 is a cross-sectional view taken along line AA in FIG.
4 is a perspective view of a case substrate used in the electronic component shown in FIG.
FIG. 5 is an exploded perspective view of a case substrate.
6 is a circuit diagram of the electronic component shown in FIG.
7 is a perspective view of a piezoelectric element mounted on the electronic component shown in FIG. 1. FIG.
FIG. 8 is a perspective view showing an electrode shape in the middle of manufacturing a case substrate.
FIG. 9It is a premise of the present inventionIt is process drawing which shows the 1st step of the electrode formation method of a case board | substrate.
FIG. 10It is a premise of the present inventionIt is process drawing which shows the 2nd step of the electrode formation method of a case board | substrate.
FIG. 11It is a premise of the present inventionIt is process drawing which shows the 3rd step of the electrode formation method of a case board | substrate.
FIG.According to the present inventionHolding jigFirstIt is a perspective view of an Example.
13 is a cross-sectional view taken along line BB in FIG.
14 is a cross-sectional view taken along the line CC of FIG.
15 is a modification of the convex portion of the holding jig shown in FIG.
FIG. 16 shows the holding jig.Reference exampleFIG.
FIG. 17 is a perspective view of a second embodiment of the case substrate.
FIG. 18 is a perspective view of a third embodiment of a case substrate.
FIG. 19 is a process diagram of a conventional example in which a transfer method and a sputtering method are used in combination.
[Explanation of symbols]
1 Case substrate (electronic component)
2 First external electrode
3 Second external electrode
10 Piezoelectric elements
20 cap
30 First transfer plate
31-33 groove
40 First holding jig
50 Second holding jig
60 Second transfer plate
61, 62 groove
70 Holding jig
71 Convex
S conductive paste

Claims

A method of forming an electrode that circulates in a headband shape on an outer peripheral surface of an electronic component having first and second main surfaces opposite to each other,
Filling the first conductive paste into a groove provided on the surface of the first transfer plate having elasticity;
With the second main surface of the electronic component held in close contact with the first holding jig having adhesiveness , the first main surface of the electronic component is pressed against the surface of the first transfer plate. Transferring the first conductive paste around the main surface of 1 and the two side surfaces connected to the main surface;
Drying the first conductive paste attached to the first main surface of the electronic component and the two side surfaces connected to the main surface ;
Filling the concave groove provided on the surface of the second transfer plate having elasticity with the second conductive paste;
The second main surface of the electronic component is pressed against the surface of the second transfer plate in a state where the first main surface of the electronic component is closely held by the second holding jig having adhesiveness . The second conductive paste wraps around the two main surfaces and the two side surfaces continuous to the main surface, and the second conductive paste that wraps around the side surfaces is connected to the first conductive paste formed on the side surfaces. And the process of transferring to
Drying the second conductive paste attached to the second main surface of the electronic component and the two side surfaces continuous to the main surface ;
First after the drying, a step of a baking the second conductive paste electrode was perforated,
The first holding jig has a convex portion extending in a direction orthogonal to the concave groove of the first transfer plate and having a width smaller than the width of the electronic component in the concave groove direction. The surface has adhesiveness that holds the central portion in the width direction of the second main surface of the electronic component in close contact,
The second holding jig has a convex portion extending in a direction orthogonal to the concave groove of the second transfer plate and having a width smaller than the width of the electronic component in the concave groove direction. A method for forming an electrode of an electronic component, characterized in that the surface has adhesiveness that holds the central portion in the width direction of the first main surface of the electronic component in close contact .

2. The convex portions of the first holding jig and the second holding jig are obtained by forming an adhesive coating on the surface layer portion of a convex core material made of a rigid body. An electrode forming method for an electronic component as described in the above item.

The adhesive strength of the second holding jig is greater than the adhesive strength of the first holding jig,
After drying the first conductive paste while holding the electronic component on the first holding jig, the first main surface of the electronic component is brought into close contact with the surface of the second holding jig, and the electronic component is moved to the first holding jig. The method of forming an electrode for an electronic component according to claim 1 or 2 , wherein the holding jig is transferred to the second holding jig.