JP4548928B2

JP4548928B2 - Electrode built-in body and wafer support member using the same

Info

Publication number: JP4548928B2
Application number: JP2000333837A
Authority: JP
Inventors: 恒彦中村
Original assignee: Kyocera Corp
Current assignee: Kyocera Corp
Priority date: 2000-10-31
Filing date: 2000-10-31
Publication date: 2010-09-22
Anticipated expiration: 2020-10-31
Also published as: JP2002141404A

Description

【０００１】
【発明の属する技術分野】
本発明は、電極を内蔵したセラミック体や電極を内蔵した樹脂層を接合したセラミック体に、上記電極と電気的に接続される給電端子を備えた電極内蔵体とこれを用いたウエハ支持部材に関するものである。
【０００２】
【従来の技術】
従来、オゾン発生器、静電吸着部材、酸素センサー、気化装置、ダイボンディング装置等には、セラミック体や樹脂層中に電極を内蔵した電極内蔵体が使用されている。
【０００３】
例えば、半導体製造プロセスでは、ドライ化が急速に進み、エッチング装置、プラズマＣＶＤ装置、プラズマＰＶＤ装置、イオン注入装置、電子ビーム描画装置、イオンビーム描画装置、Ｘ線描画装置等の半導体製造装置では、半導体ウエハ(以下、ウエハという)を真空雰囲気中で処理するため、静電チャックやサセプタなどのウエハ支持部材が使用されている。
【０００４】
図５に従来のウエハ支持部材の一例を示すように、このウエハ支持部材２１は、円盤状をしたセラミック体２２の上面をウエハＷの設置面２３とするとともに、上記セラミック体２２中に電極２４を埋設したもので、上記セラミック体２２の下面には、上記電極２４と電気的に接続される金属製の給電端子２５を接合してある。
【０００５】
また、上記ウエハ支持部材２１を形成する板状セラミック体２２と給電端子２５とを接合する手段として、特開平５−１０１８７１号公報には、図６に示すように、電極２４と給電ブロック体２６をワイヤ２７を介して電気的に接続したものを金型内に設置し、この金型内にセラミック原料を充填してホットプレスによって焼結させることにより、ワイヤ２７によって電気的に接続された電極２４と給電ブロック体２６を一体的に埋設してなるセラミック体２２を製作し、該セラミック体２２の表面に露出する給電ブロック体２６の雌ねじ部２６ａに給電端子２５の雄ねじ部２５ａを螺合させることにより、給電端子２５を電極２４と電気的に接続するようにしたものが提案されている。
【０００６】
また、特開平１０―１８９６９６号公報には、図７に示すように、セラミック体２２の下面に電極２４と連通する穴２２ａを穿孔し、該穴２２ａの内壁面にメタライズ層２８を形成した後、給電端子２５を挿入し、ロウ材層２９を介してロウ付けすることにより、給電端子２５を電極２４と電気的に接続するようにしたものが提案されている。
【０００７】
【発明が解決しようとする課題】
しかしながら、図６に示す給電構造を有するウエハ支持部材２１では、ホットプレスによりセラミック体２２を焼結させる際に異材質の給電ブロック体２６が埋設されていることから、その周囲のセラミック部に発生した応力が残留応力として残り、セラミック部にクラックが発生し易く製造歩留りが悪いといった課題があった。しかも、この給電構造の場合、ホットプレスのように大がかりな焼成装置を用いなければならないといった課題もあった。
【０００８】
また、図７に示す接合構造を有するウエハ支持部材２１では、ロウ付け後、セラミック体２２、給電端子２５、及びロウ材層２９間における熱膨張差によって室温まで冷却する際に発生する残留応力によって、セラミックス体２２に形成した穴２２ａのコーナー部を起点とするクラックが発生し易く製造歩留りが悪いといった課題があった。
【０００９】
このように、いずれの給電構造においても製造歩留りが悪く、容易にかつ確実に内部電極との接続が可能な給電構造を有するウエハ支持部材は未だ得られていなかった。
【００１０】
【課題を解決するための手段】
そこで、上記課題に鑑み、請求項１に係る発明は、電極を内蔵したセラミック体の表面又は電極を内蔵した樹脂層を接合したセラミック体の表面に、上記電極の一部が露出する凹部を設け、該凹部に上記セラミック体との熱膨張差が２×１０ ^−７／℃以下の金属からなる給電端子を挿入するとともに、該給電端子と上記凹部とを、導電性粒子を１０〜９０容量％の範囲で含有する樹脂系接着剤からなり弾性率が５〜９０ＧＰａの接着層にて接着固定して電極内蔵体を構成したものである。
請求項２に係る発明は、上記凹部の内径が１．５〜１５ｍｍの円形孔であり、上記凹部に挿入する上記給電端子の挿入部の外径と上記凹部の内径との差が０．０５〜０．３ｍｍであることを特徴とする。
請求項３に係る発明は、電極を内蔵したセラミック体の表面又は電極を内蔵した樹脂層を接合したセラミック体の表面に、上記電極の一部が露出する内径が１．５〜１５ｍｍの円形孔の凹部を設け、該凹部に挿入部の外径と上記凹部の内径との差が０．０５〜０．３ｍｍである給電端子を挿入するとともに、該給電端子と上記凹部とを、導電性粒子を１０〜９０容量％の範囲で含有する樹脂系接着剤からなる接着層にて接着固定したことを特徴とする。
【００１１】
請求項４に係る発明は、上記導電性粒子として、金、銀、銅、錫、アルミニウムのうちの少なくとも１種以上を用いたことを特徴とする。
【００１２】
請求項５に係る発明は、上記樹脂系接着剤を形成する樹脂として、エポキシ樹脂、シリコン樹脂、フッ素樹脂のいずれか１種を用いたことを特徴とする。
【００１３】
請求項６に係る発明は、上記電極内蔵体を形成する、電極を内蔵したセラミック体の表面又は電極を内蔵した樹脂層の表面をウエハの設置面としてウエハ支持部材を形成したことを特徴とする。
【００１４】
請求項７に係る発明は、請求項６に係るウエハ支持部材において、電極が、静電吸着用電極又はプラズマ電極のいずれかであることを特徴とする。
【００１５】
【発明の実施の形態】
以下、本発明の実施形態について説明する。
【００１６】
図１は本発明に係る電極内蔵体の一例であるウエハ支持部材を示す断面図である。
【００１７】
このウエハ支持部材１は、円盤状をしたセラミック体２の上面をウエハの設置面３とするとともに、上記セラミック体２中に電極４を埋設したもので、上記セラミック体２の下面には、上記電極４と電気的に接続される金属製の給電端子５を接合してある。
【００１８】
また、図２に図１のウエハ支持部材における給電構造を拡大した断面図を示すように、セラミック体２の下面には、電極４の一部が露出する凹部２ａを形成してあり、該凹部２ａには給電端子５を挿入し、導電性粒子を１０〜９０容量％の範囲で含有する樹脂系接着剤からなる接着層６にて接着固定することにより、給電端子５を電極４と電気的に接続してある。
【００１９】
そして、このウエハ支持部材１に内蔵する電極４を静電吸着用電極として用いる場合、設置面３に半導体ウエハ等のウエハＷを載せ、このウエハＷと電極４との間に電圧を印加することで、ウエハＷと電極４との間に誘電分極によるクーロン力や微少な漏れ電流によるジョンソン・ラーベック力等の静電吸着力を発現させ、ウエハＷを設置面３に吸着固定させることができ、また、電極４をプラズマ発生用電極として用いる場合、設置面３の上方に設けた別のプラズマ発生用電極と電極４との間に高周波電力を印加することで、両電極間にプラズマを発生させることができる。
【００２０】
また、本発明によれば、セラミック体２の下面に穿孔した凹部２ａに給電端子５を挿入し、樹脂系接着剤からなる接着層６にて接着固定してあることから、給電端子５の接合時にセラミック体２を破損させるようなことはなく、また、ウエハ支持部材１に使用中において、給電端子５とセラミック体２との接合部が別の熱源によって加熱されたり、給電端子５に印加する電流や高周波電力によって発熱したりしたとしても、セラミック体２を破損させることがない。
【００２１】
即ち、本発明によれば、セラミック体２と金属からなる給電端子５との間の熱膨張差による応力が発生したとしても、この応力を接着層６で吸収することができるため、セラミック体２の破損を防止することができる。
【００２２】
また、接着層６を形成する樹脂系接着剤には導電性粒子を含有させて導電性を持たせてあることから、長期間にわたり安定した通電を行うことができる。
【００２３】
しかも、従来のようにホットプレス装置を用いたり、ロウ付け等の高温に加熱したりする必要がないため、容易に製造することができる。
【００２４】
ところで、給電端子５に印加された電力をロスなく電極４へ通電するためには、接着層６に十分な導電性を持たせる必要があるが、導電性粒子の含有量が１０容量％を下回ると、給電端子５と電極４との間の抵抗が大きくなって電力ロスを生じ易くなるとともに、接合部が異常発熱し、接着層６を劣化させてしまうことになる。ただし、導電性粒子の含有量が９０容量％を超えると、接着強度が低下し、給電端子５がセラミック体２の凹部２ａから落下するおそれがある。
【００２５】
その為、十分な接着強度を維持しつつ、十分な導電性を得るためには、接着層６を形成する樹脂系接着剤に含有させる導電性粒子は、１０〜９０容量％の範囲で含有することが良く、好ましくは２０〜９０容量％の範囲で含有することが良い。
【００２６】
また、導電性粒子の材質としては、導電率が大きく、樹脂系接着剤との反応が小さく、しかも耐熱性に優れたものが良く、例えば、金、銀、銅、錫、アルミニウムを用いることができる。特に、金、銀、銅は導電率の点で好ましく、さらに樹脂系接着剤との反応が小さい点で金と銀が望ましい。なお、導電性粒子の最大粒子経は２〜５０μｍの範囲にあるものを用いることが好ましい。
【００２７】
一方、接着層６を形成する樹脂系接着剤の樹脂材としては、エポキシ樹脂、シリコン樹脂、フッ素系樹脂及びこれらを混合した樹脂が、上述した導電性粒子との反応が小さく、さらに耐熱性に優れるとともに、経時変化が少ない点で好適である。
【００２８】
また、−５０℃〜２００℃の温度範囲内における熱サイクルや温度変化に対し、セラミック体２と金属からなる給電端子５との熱膨張差による応力を吸収し、セラミック体２の破損を防止するためには、接着層６の弾性率を５〜９０ＧＰａ、好ましくは１０〜４０ＧＰａ、望ましくは１５〜３５ＧＰａとすることが良い。
【００２９】
なぜなら、接着層６の弾性率が５ＧＰａ未満であると、−５０℃〜２００℃の温度範囲内における熱サイクルや温度変化によって給電端子５の緩みが生じ易く、給電端子５が脱落するおそれがあるからであり、逆に接着層６の弾性率が９０ＧＰａを超えると、セラミック体２と金属からなる給電端子５との間の熱膨張差による応力が吸収する効果が小さく、セラミック体２にクラックが生じ易くなるからである。
【００３０】
ところで、セラミック体２を形成するセラミックスとしては、アルミナ質焼結体、窒化珪素質焼結体、窒化アルミニウム質焼結体等を用いることができる。
【００３１】
また、給電端子５を形成する金属としては、セラミック体２との熱膨張差ができるだけ小さいものが良く、好ましくは熱膨張差が２×１０^-7／℃以下であるものが良く、例えばセラミック体２が窒化アルミニウ質焼結体からなる場合、給電端子５はＦｅ−Ｃｏ−Ｎｉ合金を用いれば良い。
【００３２】
なお、セラミック体２に形成する凹部２ａの形状としては特に限定するものではないが、円形であるものが製作性の点で好ましい。ただし、凹部２ａの内径が１５ｍｍを超えると、切削加工時に凹部２ａの開口エッジ部に欠けやクラックが発生し易くなり、逆に凹部２ａの内径が１．５ｍｍより小さくなると、給電端子５の径が小さくなり、リード線の取り付けにあたってネジ止め等の手段にて簡単に取り付けることができなくなるといった不都合がある。
【００３３】
その為、セラミック体２に形成する凹部２ａの内径は１．５〜１５ｍｍの円形孔とすることが良い。
【００３４】
また、セラミック体２の凹部２ａに挿入する給電端子５は、その挿入部５ａの外径を、凹部２ａの内径との差が０．０５〜０．３ｍｍとなるようにすることが良い。
【００３５】
これは、凹部２ａの内径と挿入部５ａの外径との差が０．０５ｍｍ未満では、挿入部５ａを凹部２ａ内に挿入することが難しく、凹部２ａのコーナー部等よりセラミック体２にクラックを発生させるおそれがあるからであり、逆に凹部２ａの内径と挿入部５ａの外径との差が０．３ｍｍを超えると、給電端子５とセラミック体２に設けられた凹部２ａの間の接着層６の層厚みが大きくなり、温度サイクルによる接着層６の膨張や収縮が、給電端子５と凹部２ａとの間隔の変化に対して追従することができず、接着層６が凹部２ａより剥離するおそれがあるからである。
【００３６】
次に、給電端子５の接合方法について説明する。
【００３７】
まず、電極４を埋設したセラミック体２を用意する。なお、セラミック体２は、セラミックグリーンシートを複数枚積み重ね、あるセラミックグリーンシート間に導体層を形成しておいたグリーンシート積層体を焼成することにより形成したものや、生のセラミック成形体上に導体層を配置し、該導体層を覆うように生のセラミック成形体上にセラミック粉末を充填し、圧力を加えて導体層を埋設した生のセラミック成形体を形成したあと焼成することにより形成したもの、あるいは上記導体層を覆うように生のセラミック成形体上にセラミック粉末を充填し、圧力を加えながら加熱して焼成することにより形成したものでも構わない。
【００３８】
そして、セラミック体２の表面に研削加工にて電極４の一部が露出する凹部２ａを穿孔する。この凹部２ａの形成にあたっては、円柱状体の外周にダイヤモンド砥粒を電着等にて固着した工具を用い、セラミック体２にクラックを発生させないようにするため、送り速度を１ｍｍ／分以下の速度で行うことが好ましい。
【００３９】
次に、この穿孔した凹部２ａの内壁面（電極４の露出部も含む）に、導電性粒子を１０〜９０容量％の範囲で含有する樹脂系接着剤を塗布し、給電端子５の挿入部５ａを凹部２ａ内に挿入する。しかる後、２４時間以上室温で樹脂系接着剤を硬化させるか、あるいは１５０℃以下の温度で６時間程加熱して樹脂系接着剤を硬化させて接着層６を形成すれば良い。
【００４０】
このように、本発明によれば、大きな熱を加える必要がないことから、セラミック体２と金属からなる給電端子５との熱膨張差による応力によってセラミック体２を破損させることなく、容易に製造することができる。
【００４１】
以上、本発明の実施形態について説明したが、本発明は図１に示したものだけに限定されるものではなく、例えば、図３や図４に示す電極内蔵体にも適用することができる。
【００４２】
図３は、本発明に係る電極内蔵体からなるウエハ支持部材の他の例を示す断面図で、電極４を内蔵したセラミック体２が、セラミック焼結体やサファイアからなる誘電体層１１の上面をウエハの設置面３とし、上記誘電体層１１の下面に電極４を、メッキ法やメタライズ法、あるいはＣＶＤ法、ＰＶＤ法、スパッタリング法等の成膜手段にて形成し、上記電極４を覆うように上記誘電体層１１の下面に、セラミック焼結体からなるベース１２を接着剤やロウ材にて接合した接合構造体からなる以外は図１と同様の構造をしたもので、図２に示す給電構造にて給電端子５を接合してある。
【００４３】
また、図４は、本発明に係る電極内蔵体からなるウエハ支持部材のさらに他の例を示す断面図で、電極４を内蔵したセラミック体２が、電極４を埋設した樹脂層１３の上面をウエハの設置面３とするとともに、樹脂層１３の下面に、セラミック焼結体からなるベース１２を接着剤やロウ材にて接合した接合構造体からなる以外は図１と同様の構造をしたもので、図２に示す給電構造にて給電端子５を接合してある。
【００４４】
また、本実施形態ではウエハ支持部材を例にとって説明したが、この他に、オゾン発生器、静電吸着部材、酸素センサー、気化装置、ダイボンディング装置等の電極内蔵体にも適用できることは言う迄もない。
【００４５】
【実施例】
以下、本発明の具体例をウエハ支持部材を例にとって説明する。
【００４６】
まず、セラミック体２を形成するため、平均粒子径が１．２μｍ程度である純度９９．０％のＡｌＮ粉末に、バインダー及び溶媒のみを添加混合して泥漿を製作した後、ドクターブレード法にて厚さ０．５ｍｍ程度のＡｌＮグリーンシートを複数枚製作し、このうち、数枚のＡｌＮグリーンシートを積層した後、その表面にスクリーン印刷法でもってタングステン粉末に若干のＡｌＮ粉末を混ぜた金属ペーストからなる半円状膜を円形に敷設し、さらに残りのＡｌＮグリーンシートを積み重ね、５０ｋｇ／ｃｍ²の圧力で加圧圧着してグリーンシート積層体を形成した。その後、切削加工を施して円板状とした後、窒素雰囲気下で２０００℃程度の焼成温度で２時間程度焼成することにより、純度９９．０％の窒化アルミニウム質焼結体からなり、その内部に電極を埋設したセラミック体を得た。
【００４７】
しかる後、セラミック体の外径を約２００ｍｍ、厚みを８ｍｍとした後、セラミック体の一方の主面（最も広い面）に、研摩加工を施して中心線平均粗さ（Ｒａ）０．８μｍの鏡面に仕上げて設置面を形成するとともに、セラミック体の他方の主面に電極の一部が露出する円形の凹部を研削加工にて穿孔し、凹部中に、導電性粒子として最大粒子径が２０μｍのＡｇを用い、１０容量％の割合で添加したエポキシ系接着剤を塗布し、Ｆｅ−Ｃｏ−Ｎｉ系合金からなる給電端子を挿入した後、１５０℃の温度で加熱硬化させて接着層を形成し、給電端子を凹部内に接着固定することによりウエハ支持部材を製作した。
【００４８】
このようにして製作したウエハ支持部材は、給電端子の接合時にセラミック体を破損させることがなく、容易に製作することができた。
【００４９】
【実験例】
（実験例１）
そこで、実施例のウエハ支持部材のうち、接着層を形成するエポキシ系接着剤に含有させる導電性粒子の割合を異ならせた時の給電端子と電極との間の抵抗値、給電端子の引っ張り強度、ウエハ支持部材に熱サイクルを加えた時の通電不良の発生率についてそれぞれ調べる実験を行った。
【００５０】
そして、本実験では、給電端子と電極との間の抵抗値が０．５Ω以下であるものを良好とし、○で示し、０．５Ωを超えるものは不良とし、×で示した。また、給電端子の引っ張り強度においては、引っ張り強度が９．８Ｎ以上であるものを良好とし、○で示し、９．８Ｎ未満であるものを不良とし、×で示した。さらに、ウエハ支持部材に熱サイクルを加えた時の通電不良の発生率については、各試料をそれぞれ２０個ずつ用意し、昇降温レートを５０℃／分とし、−５０℃と２００℃でそれぞれ１０分間保持する温度サイクルを１０００サイクル実施後に、さらに２００℃に加熱して１０００時間保持した後、給電端子と電極との間の抵抗を測定し、初期の抵抗値に対する変化率を１％以下とできなかったものの発生率を示し、この発生率が５％以下であるものを良好とした。
【００５１】
それぞれの結果は表１に示す通りである。なお、給電端子と電極との間の抵抗値は四端子法により測定した。
【００５２】
【表１】

【００５３】
この結果、試料Ｎｏ．２〜９のように、導電性粒子の含有量が１０〜９０容量％の範囲あるものは、いずれも給電端子と電極との間の抵抗値を０．５Ω以下とすることができ、十分な導電性が得られるとともに、−５０℃から２００℃の熱サイクルに対しても抵抗値変化が少なく、熱サイクルによる導通不良発生率も５％以下と少なく、さらに、給電端子を強固に接合することができ、優れていた。
【００５４】
この結果、接合層を形成する樹脂中に含有させる導電性粒子の含有量は１０〜９０容量％の範囲で含有すれば良いことが判る。
【００５５】
（実験例２）
次に、接着層を形成する樹脂の種類及び導電性粒子の種類をそれぞれ異ならせ、実験例１と同様の実験を行った。
【００５６】
それぞれの結果は表２に示す通りである。
【００５７】
【表２】

【００５８】
この結果、試料Ｎｏ．１２〜１４，１６，１７，１９，２０，２４のように、導電性粒子として金、銀、銅、錫、アルミニウムを用いるとともに、導電性接着剤を形成する樹脂成分として、エポキシ樹脂、シリコン樹脂、フッ素樹脂のいずれか１種を用いることにより、給電端子と電極との間の抵抗値を０．５Ω以下とすることができ、十分な導電性が得られるとともに、−５０℃から２００℃の熱サイクル試験に対しても抵抗値の変化が少なく、導通不良率を５％以下に抑えることができ、さらに、給電端子を強固に接合することができることが判る。
【００５９】
この結果、接合層を形成する樹脂系接着剤中に含有させる導電性粒子は、金、銀、銅、錫、アルミニウムを用いるとともに、樹脂系接着剤を形成する樹脂成分は、エポキシ樹脂、シリコン樹脂、フッ素樹脂のいずれか１種を用いることが良い。
【００６０】
【発明の効果】
以上のように、本発明によれば、電極を内蔵したセラミック体の表面又は電極を内蔵した樹脂層を接合したセラミック体の表面に、上記電極の一部が露出する凹部を設け、該凹部に給電端子を挿入するとともに、該給電端子と上記凹部とを、導電性粒子を１０〜９０容量％の範囲で含有する樹脂系接着剤からなる接着層にて接着固定して電極内蔵体を構成したことから、給電端子と電極との間の十分な導電性が得られ、かつ−５０度〜２００度の温度範囲で熱サイクルが加わったとしてもセラミック体を破損させることなく確実に給電端子を接合することができる。しかも、給電端子の接合時に大きな熱を加える必要がないため、給電端子の接続を容易に行うことができる。
【００６１】
特に、上記導電性粒子として、金、銀、銅、錫、アルミニウムのうちの少なくとも１種以上を用いるとともに、樹脂系接着剤を形成する樹脂として、エポキシ樹脂、シリコン樹脂、フッ素樹脂のいずれか１種を用いれば上記効果を効果的に達成することができる。
【００６２】
その為、本発明の電極内蔵体を用いて電極が静電吸着用電極又はプラズマ電極からなるウエハ支持部材を形成すれば、電極が静電吸着用電極である時には、ウエハを吸着固定するのに十分な静電気力を発生させることができ、また電極がプラズマ電極である時には、各種処理を行うのに十分なプラズマを発生させることができる。
【図面の簡単な説明】
【図１】本発明に係る電極内蔵体の一例であるウエハ支持部材を示す断面図である。
【図２】図１のウエハ支持部材における給電構造を拡大した断面図である。
【図３】本発明に係るウエハ支持部材の他の例を示す断面図である。
【図４】本発明に係るウエハ支持部材のさらに他の例を示す断面図である。
【図５】従来の電極内蔵体の一例であるウエハ支持部材を示す断面図である。
【図６】図５のウエハ支持部材における給電構造の一例を示す拡大断面図である。
【図７】図５のウエハ支持部材における給電構造の他の例を示す拡大断面図である。
【符号の説明】
１，２１：ウエハ支持部材２，２２：セラミック体２ａ，２２ａ：凹部
３，２３：設置面４，２４：電極５，２５：給電端子６：接着層[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a built-in electrode body including a power supply terminal electrically connected to the ceramic body in which an electrode is embedded and a ceramic body in which a resin layer including the electrode is bonded, and a wafer support member using the same. Is.
[0002]
[Prior art]
Conventionally, an ozone generator, an electrostatic adsorption member, an oxygen sensor, a vaporizer, a die bonding apparatus, and the like have used a built-in electrode body in which an electrode is incorporated in a ceramic body or a resin layer.
[0003]
For example, in the semiconductor manufacturing process, the dry process rapidly progresses, and in semiconductor manufacturing apparatuses such as an etching apparatus, a plasma CVD apparatus, a plasma PVD apparatus, an ion implantation apparatus, an electron beam drawing apparatus, an ion beam drawing apparatus, and an X-ray drawing apparatus, In order to process a semiconductor wafer (hereinafter referred to as a wafer) in a vacuum atmosphere, a wafer support member such as an electrostatic chuck or a susceptor is used.
[0004]
As shown in FIG. 5 as an example of a conventional wafer support member, the wafer support member 21 has an upper surface of a disk-shaped ceramic body 22 as an installation surface 23 of the wafer W, and an electrode 24 in the ceramic body 22. A metal power supply terminal 25 electrically connected to the electrode 24 is bonded to the lower surface of the ceramic body 22.
[0005]
As a means for joining the plate-like ceramic body 22 forming the wafer support member 21 and the power supply terminal 25, Japanese Patent Laid-Open No. 5-101871 discloses an electrode 24 and a power supply block body 26 as shown in FIG. An electrode electrically connected through a wire 27 is placed in a mold, and a ceramic raw material is filled in the mold and sintered by hot pressing, whereby an electrode electrically connected by a wire 27 is provided. 24 and the power supply block body 26 are integrally embedded, and the male screw portion 25a of the power supply terminal 25 is screwed into the female screw portion 26a of the power supply block body 26 exposed on the surface of the ceramic body 22. Thus, a device in which the power supply terminal 25 is electrically connected to the electrode 24 has been proposed.
[0006]
Further, in Japanese Patent Laid-Open No. 10-189696, as shown in FIG. 7, a hole 22a communicating with the electrode 24 is formed on the lower surface of the ceramic body 22, and a metallized layer 28 is formed on the inner wall surface of the hole 22a. A power supply terminal 25 is inserted and brazed via a brazing material layer 29 so that the power supply terminal 25 is electrically connected to the electrode 24.
[0007]
[Problems to be solved by the invention]
However, in the wafer support member 21 having the power supply structure shown in FIG. 6, when the ceramic body 22 is sintered by hot pressing, the power supply block body 26 made of a different material is embedded, and thus generated in the surrounding ceramic portion. The remaining stress remains as residual stress, and cracks are likely to occur in the ceramic part, resulting in a problem in that the production yield is poor. Moreover, in the case of this power supply structure, there is a problem that a large-scale baking apparatus such as a hot press must be used.
[0008]
Further, in the wafer support member 21 having the bonding structure shown in FIG. 7, the residual stress generated when the ceramic body 22, the power supply terminal 25, and the brazing material layer 29 are cooled to room temperature due to the difference in thermal expansion after the brazing. There is a problem that cracks starting from the corners of the holes 22a formed in the ceramic body 22 are likely to occur and the manufacturing yield is poor.
[0009]
Thus, in any of the power feeding structures, the production yield is poor, and a wafer support member having a power feeding structure that can be easily and reliably connected to the internal electrode has not been obtained.
[0010]
[Means for Solving the Problems]
Accordingly, in view of the above problems, the invention according to claim 1 is provided with a recess in which a part of the electrode is exposed on the surface of the ceramic body incorporating the electrode or the surface of the ceramic body joined with the resin layer incorporating the electrode. In addition, a power feeding terminal made of a metal having a thermal expansion difference of 2 × 10 ⁻⁷ / ° C. or less with respect to the ceramic body is inserted into the recess, and 10 to 90% by volume of conductive particles are connected between the power feeding terminal and the recess. Do Ri modulus of a resin-based adhesive containing a range of is that constitutes the bonded stationary electrode internal body by an adhesive layer of 5～90GPa.
The invention according to claim 2 is a circular hole in which the inner diameter of the recess is 1.5 to 15 mm, and the difference between the outer diameter of the insertion portion of the power supply terminal inserted into the recess and the inner diameter of the recess is 0.05. It is characterized by being -0.3 mm.
According to a third aspect of the present invention, there is provided a circular hole having an inner diameter of 1.5 to 15 mm from which a part of the electrode is exposed on the surface of the ceramic body containing the electrode or the surface of the ceramic body joined with the resin layer containing the electrode. The power supply terminal having a difference between the outer diameter of the insertion portion and the inner diameter of the concave portion of 0.05 to 0.3 mm is inserted into the concave portion, and the power supply terminal and the concave portion are connected to the conductive particles. Is bonded and fixed by an adhesive layer made of a resin adhesive containing 10 to 90% by volume.
[0011]
The invention according to claim 4 is characterized in that at least one of gold, silver, copper, tin and aluminum is used as the conductive particles.
[0012]
The invention according to claim 5 is characterized in that any one of an epoxy resin, a silicon resin, and a fluororesin is used as the resin for forming the resin adhesive.
[0013]
The invention according to claim 6 is characterized in that the wafer support member is formed with the surface of the ceramic body or the surface of the resin layer incorporating the electrode forming the electrode built-in body as the wafer installation surface. .
[0014]
The invention according to claim 7 is the wafer support member according to claim 6 , wherein the electrode is either an electrostatic chucking electrode or a plasma electrode.
[0015]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described.
[0016]
FIG. 1 is a cross-sectional view showing a wafer support member which is an example of an electrode built-in body according to the present invention.
[0017]
The wafer support member 1 has an upper surface of a disk-shaped ceramic body 2 as a wafer installation surface 3 and an electrode 4 embedded in the ceramic body 2. A metal power supply terminal 5 electrically connected to the electrode 4 is joined.
[0018]
Further, as shown in FIG. 2 which is an enlarged cross-sectional view of the power feeding structure in the wafer support member of FIG. 1, a recess 2a in which a part of the electrode 4 is exposed is formed on the lower surface of the ceramic body 2. The power supply terminal 5 is inserted into 2a and bonded and fixed with an adhesive layer 6 made of a resin-based adhesive containing conductive particles in a range of 10 to 90% by volume, whereby the power supply terminal 5 is electrically connected to the electrode 4. Is connected to.
[0019]
When using an electrode 4 incorporated in the wafer support member 1 as an electrostatic attraction electrodes, placing the wafer W such as a semiconductor wafer to the installation surface 3, to mark pressurizing the voltage between the wafer W and the electrode 4 As a result, an electrostatic adsorption force such as a Coulomb force due to dielectric polarization or a Johnson-Rahbek force due to a minute leakage current can be expressed between the wafer W and the electrode 4, and the wafer W can be adsorbed and fixed to the installation surface 3. , in the case of using the electrode 4 as a plasma generating electrode, by indicia pressure to the high-frequency power between the different plasma generating electrode and the electrode 4 provided above the installation surface 3, a plasma between both electrodes Can be generated.
[0020]
In addition, according to the present invention, since the power supply terminal 5 is inserted into the recess 2a drilled in the lower surface of the ceramic body 2 and bonded and fixed by the adhesive layer 6 made of a resin-based adhesive, never such as to damage the ceramic body 2 when, also during use in the wafer support member 1, or the joint between the feeding terminal 5 and the ceramic body 2 is heated by another heat source, indicia pressure to the power supply terminal 5 even with or heating by the current and high-frequency power, there is no damaging the ceramic body 2.
[0021]
That is, according to the present invention, even if a stress due to the difference in thermal expansion between the ceramic body 2 and the power supply terminal 5 made of metal occurs, the stress can be absorbed by the adhesive layer 6, so that the ceramic body 2 Can be prevented from being damaged.
[0022]
In addition, since the resin-based adhesive forming the adhesive layer 6 is made conductive by containing conductive particles, stable energization can be performed over a long period of time.
[0023]
Moreover, since it is not necessary to use a hot press apparatus or to heat to a high temperature such as brazing as in the prior art, it can be manufactured easily.
[0024]
Meanwhile, in order to energize the electric power indicia pressurized to the power supply terminal 5 to without loss electrode 4, it is necessary to have sufficient conductivity to the adhesive layer 6, a 10% by volume content of the conductive particles If it falls below, the resistance between the power supply terminal 5 and the electrode 4 will increase, and it will become easy to produce a power loss, and a junction part will generate | occur | produce abnormally heat | fever, and the adhesive layer 6 will be deteriorated. However, the content of the conductive particles obtain super 90 volume%, the adhesive strength is lowered, the feeding terminal 5 is Re emesis dropping from the recess 2a of the ceramic body 2.
[0025]
Therefore, in order to obtain sufficient electrical conductivity while maintaining sufficient adhesive strength, the conductive particles contained in the resin-based adhesive forming the adhesive layer 6 are contained in a range of 10 to 90% by volume. It is preferable that it is contained in the range of 20 to 90% by volume.
[0026]
Moreover, as the material of the conductive particles, a material having a high conductivity, a small reaction with the resin-based adhesive, and excellent heat resistance is preferable. For example, gold, silver, copper, tin, or aluminum is used. it can. In particular, gold, silver, and copper are preferable from the viewpoint of electrical conductivity, and gold and silver are preferable from the viewpoint that reaction with the resin adhesive is small. In addition, it is preferable to use what the maximum particle diameter of electroconductive particle exists in the range of 2-50 micrometers.
[0027]
On the other hand, as a resin material of the resin-based adhesive forming the adhesive layer 6, epoxy resin, silicon resin, fluorine-based resin, and a resin obtained by mixing these resins have a small reaction with the above-described conductive particles, and further heat resistance. It is excellent in that it is excellent and changes with time are small.
[0028]
Further, the thermal cycle and temperature change within the temperature range of −50 ° C. to 200 ° C. absorbs stress due to the difference in thermal expansion between the ceramic body 2 and the power supply terminal 5 made of metal, and prevents the ceramic body 2 from being damaged. For this purpose, the elastic modulus of the adhesive layer 6 is 5 to 90 GPa, preferably 10 to 40 GPa, and desirably 15 to 35 GPa.
[0029]
This is because if the elastic modulus of the adhesive layer 6 is less than 5 GPa, easily occurs looseness of the feeding terminal 5 by thermal cycling or temperature change within the temperature range of -50 ° C. to 200 DEG ° C., but is late feeding terminal 5 from falling On the contrary, when the elastic modulus of the adhesive layer 6 exceeds 90 GPa, the effect of absorbing stress due to the difference in thermal expansion between the ceramic body 2 and the power supply terminal 5 made of metal is small, and the ceramic body 2 is cracked. It is because it becomes easy to occur.
[0030]
By the way, as ceramics which form the ceramic body 2, an alumina sintered body, a silicon nitride sintered body, an aluminum nitride sintered body and the like can be used.
[0031]
Further, the metal forming the power supply terminal 5 is preferably a metal having a difference in thermal expansion as small as possible with respect to the ceramic body 2, and preferably has a difference in thermal expansion of 2 × 10 ⁻⁷ / ° C. or less. When 2 is made of an aluminum nitride sintered body, the feeding terminal 5 may be made of an Fe—Co—Ni alloy.
[0032]
The shape of the recess 2a formed in the ceramic body 2 is not particularly limited, but a circular shape is preferable in terms of manufacturability. However, if the inner diameter of the concave portion 2a exceeds 15 mm, chipping or cracking is likely to occur at the opening edge portion of the concave portion 2a during cutting, and conversely, if the inner diameter of the concave portion 2a is smaller than 1.5 mm, the diameter of the feeding terminal 5 This leads to a disadvantage that the lead wire cannot be easily attached by means such as screwing when attaching the lead wire.
[0033]
Therefore, the inner diameter of the recess 2a formed in the ceramic body 2 is preferably a circular hole having a diameter of 1.5 to 15 mm.
[0034]
In addition, the power supply terminal 5 to be inserted into the recess 2a of the ceramic body 2 is preferably configured such that the difference between the outer diameter of the insertion portion 5a and the inner diameter of the recess 2a is 0.05 to 0.3 mm.
[0035]
This is because if the difference between the inner diameter of the concave portion 2a and the outer diameter of the insertion portion 5a is less than 0.05 mm, it is difficult to insert the insertion portion 5a into the concave portion 2a, and the ceramic body 2 cracks from the corner portion of the concave portion 2a. is because there is a Re hyperemesis for generating the difference between the outer diameter of the inner diameter and the insertion portion 5a of the recess 2a in the opposite is more than 0.3 mm, between the recess 2a provided to the power supply terminal 5 and the ceramic body 2 The thickness of the adhesive layer 6 is increased, and the expansion and contraction of the adhesive layer 6 due to the temperature cycle cannot follow the change in the distance between the power supply terminal 5 and the concave portion 2a. there is a Re emesis be more peeling.
[0036]
Next, a method for joining the power supply terminals 5 will be described.
[0037]
First, the ceramic body 2 in which the electrode 4 is embedded is prepared. The ceramic body 2 is formed by stacking a plurality of ceramic green sheets and firing a green sheet laminate in which a conductor layer is formed between certain ceramic green sheets, or on a raw ceramic molded body. Formed by placing a conductor layer, filling a ceramic powder on a raw ceramic molded body so as to cover the conductor layer, forming a raw ceramic molded body in which a conductor layer is embedded by applying pressure and then firing. Alternatively, it may be formed by filling ceramic powder on a raw ceramic molded body so as to cover the conductor layer, and heating and firing while applying pressure.
[0038]
Then, a recess 2a in which a part of the electrode 4 is exposed is drilled in the surface of the ceramic body 2 by grinding. In forming the recess 2a, a tool in which diamond abrasive grains are fixed to the outer periphery of the cylindrical body by electrodeposition or the like is used, and the feed rate is 1 mm / min or less so as not to generate cracks in the ceramic body 2. It is preferable to carry out at a speed.
[0039]
Next, a resin adhesive containing conductive particles in a range of 10 to 90% by volume is applied to the inner wall surface (including the exposed portion of the electrode 4) of the perforated recess 2a, and the insertion portion of the feeding terminal 5 is inserted. 5a is inserted into the recess 2a. Thereafter, the resin adhesive may be cured at room temperature for 24 hours or more, or may be heated at a temperature of 150 ° C. or less for 6 hours to cure the resin adhesive to form the adhesive layer 6.
[0040]
As described above, according to the present invention, since it is not necessary to apply a large amount of heat, the ceramic body 2 can be easily manufactured without damaging the ceramic body 2 due to a stress due to a thermal expansion difference between the ceramic body 2 and the power feeding terminal 5 made of metal. can do.
[0041]
Although the embodiment of the present invention has been described above, the present invention is not limited to the one shown in FIG. 1 and can be applied to, for example, the electrode built-in body shown in FIG. 3 and FIG.
[0042]
FIG. 3 is a cross-sectional view showing another example of a wafer support member made of an electrode built-in body according to the present invention, wherein the ceramic body 2 containing the electrode 4 is an upper surface of a dielectric layer 11 made of a ceramic sintered body or sapphire. Is formed on the lower surface of the dielectric layer 11 by a film forming means such as a plating method, a metallization method, a CVD method, a PVD method, or a sputtering method, and covers the electrode 4. As shown in FIG. 2, the dielectric layer 11 has the same structure as that shown in FIG. 1 except that the base 12 made of a ceramic sintered body is joined to the lower surface of the dielectric layer 11 with an adhesive or brazing material. The power supply terminal 5 is joined in the power supply structure shown.
[0043]
FIG. 4 is a cross-sectional view showing still another example of a wafer support member composed of an electrode built-in body according to the present invention, in which the ceramic body 2 containing the electrode 4 covers the upper surface of the resin layer 13 in which the electrode 4 is embedded. 1 having the same structure as that of FIG. 1 except that it is made of a wafer mounting surface 3 and a bonded structure in which a base 12 made of a ceramic sintered body is bonded to the lower surface of the resin layer 13 with an adhesive or brazing material. Thus, the power supply terminal 5 is joined in the power supply structure shown in FIG.
[0044]
Further, in the present embodiment, the wafer support member has been described as an example, but in addition to this, it can be applied to an electrode built-in body such as an ozone generator, an electrostatic adsorption member, an oxygen sensor, a vaporizer, and a die bonding apparatus. Nor.
[0045]
【Example】
Hereinafter, a specific example of the present invention will be described taking a wafer support member as an example.
[0046]
First, in order to form the ceramic body 2, a slurry was prepared by adding only a binder and a solvent to an AlN powder having an average particle diameter of about 1.2 μm and a purity of 99.0%, followed by a doctor blade method. A plurality of AlN green sheets with a thickness of about 0.5 mm are manufactured. Among them, several AlN green sheets are laminated, and then a metal paste in which some AlN powder is mixed with tungsten powder by screen printing on the surface. A semi-circular film made of the above was laid in a circle, and the remaining AlN green sheets were stacked, and pressure-bonded at a pressure of 50 kg / cm ² to form a green sheet laminate. Thereafter, it is cut into a disk shape and then fired at a firing temperature of about 2000 ° C. for about 2 hours in a nitrogen atmosphere, thereby forming an aluminum nitride sintered body having a purity of 99.0%. A ceramic body having an electrode embedded therein was obtained.
[0047]
Thereafter, after the outer diameter of the ceramic body is about 200 mm and the thickness is 8 mm, one main surface (widest surface) of the ceramic body is subjected to polishing to have a center line average roughness (Ra) of 0.8 μm. The mirror surface is finished to form an installation surface, and a circular recess in which a part of the electrode is exposed is drilled in the other main surface of the ceramic body by grinding, and the maximum particle size as conductive particles is 20 μm in the recess. After applying an epoxy adhesive added at a rate of 10% by volume, and inserting a feed terminal made of an Fe—Co—Ni alloy, the adhesive layer is formed by heating and curing at a temperature of 150 ° C. Then, the wafer supporting member was manufactured by bonding and fixing the power supply terminal in the recess.
[0048]
The wafer support member manufactured in this manner could be easily manufactured without damaging the ceramic body when the power supply terminals were joined.
[0049]
[Experimental example]
(Experimental example 1)
Therefore, the resistance value between the power supply terminal and the electrode when the ratio of the conductive particles to be included in the epoxy adhesive forming the adhesive layer in the wafer support member of the example is different, and the tensile strength of the power supply terminal An experiment was carried out to examine the occurrence rate of energization failure when a thermal cycle was applied to the wafer support member.
[0050]
In this experiment, the resistance value between the power supply terminal and the electrode was 0.5Ω or less as good, indicated by ◯, and the resistance value exceeding 0.5Ω was determined as poor and indicated by x. In addition, regarding the tensile strength of the power supply terminal, those having a tensile strength of 9.8 N or more were evaluated as good, and those having a tensile strength of less than 9.8 N were evaluated as poor and indicated by x. Furthermore, regarding the occurrence rate of the energization failure when the thermal cycle is applied to the wafer support member, 20 samples are prepared, the heating / cooling rate is 50 ° C./min, and 10 ° C. at −50 ° C. and 200 ° C., respectively. After 1000 cycles of holding the temperature cycle for 1 minute, after further heating to 200 ° C. and holding for 1000 hours, the resistance between the power supply terminal and the electrode can be measured, and the rate of change with respect to the initial resistance value can be 1% or less. The occurrence rate of those that did not exist was shown, and those with an occurrence rate of 5% or less were considered good.
[0051]
Each result is as shown in Table 1. The resistance value between the power supply terminal and the electrode was measured by the four-terminal method.
[0052]
[Table 1]

[0053]
As a result, sample no. As for 2-9, what has the content of electroconductive particle in the range of 10-90 volume% can make the resistance value between a feeding terminal and an electrode 0.5 ohm or less, and is enough Conductivity is obtained, resistance value change is small even for thermal cycles from -50 ° C to 200 ° C, conduction failure occurrence rate due to thermal cycles is less than 5%, and power supply terminals are firmly joined It was possible and was excellent.
[0054]
As a result, it can be seen that the content of the conductive particles contained in the resin forming the bonding layer may be contained in the range of 10 to 90% by volume.
[0055]
(Experimental example 2)
Next, the same experiment as in Experimental Example 1 was performed by changing the type of resin forming the adhesive layer and the type of conductive particles.
[0056]
Each result is as shown in Table 2.
[0057]
[Table 2]

[0058]
As a result, sample no. As in the case of 12-14, 16, 17, 19, 20, 24, gold, silver, copper, tin, and aluminum are used as conductive particles, and epoxy resin and silicon resin are used as resin components for forming a conductive adhesive. , 200 by using the Re or one not have a fluorine resin, the resistance value between the feeding terminal and the electrode can be less 0.5 .OMEGA, with sufficient conductivity can be obtained, from -50 ° C. It can be seen that there is little change in the resistance value even with respect to the heat cycle test at 0 ° C., the conduction failure rate can be suppressed to 5% or less, and the power supply terminals can be firmly joined.
[0059]
As a result, the conductive particles included in the resin adhesive forming the bonding layer use gold, silver, copper, tin, and aluminum, and the resin components forming the resin adhesive include epoxy resin and silicon resin. it is better to use a Re or one not have a fluorine resin.
[0060]
【The invention's effect】
As described above, according to the present invention, a recess in which a part of the electrode is exposed is provided on the surface of the ceramic body containing the electrode or the surface of the ceramic body joined with the resin layer containing the electrode. The power supply terminal was inserted, and the power supply terminal and the concave portion were bonded and fixed with an adhesive layer made of a resin-based adhesive containing conductive particles in a range of 10 to 90% by volume to constitute an electrode built-in body. Therefore, sufficient electrical conductivity between the power supply terminal and the electrode can be obtained, and the power supply terminal is securely joined without damaging the ceramic body even if a thermal cycle is applied in a temperature range of −50 ° C. to 200 ° C. can do. And since it is not necessary to apply a big heat at the time of joining of a power feeding terminal, a power feeding terminal can be connected easily.
[0061]
In particular, at least one of gold, silver, copper, tin, and aluminum is used as the conductive particles, and any one of an epoxy resin, a silicon resin, and a fluororesin is used as a resin for forming a resin adhesive. If seeds are used, the above effect can be achieved effectively.
[0062]
Therefore, if the electrode supporting body is formed by using the electrode built-in body of the present invention and the electrode is an electrostatic chucking electrode or a plasma electrode, when the electrode is an electrostatic chucking electrode, the wafer is sucked and fixed. sufficient electrostatic force can be generated, and when the electrode is a plasma electrode can generate sufficient plug's Ma to perform various processes.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view showing a wafer support member which is an example of an electrode built-in body according to the present invention.
2 is an enlarged cross-sectional view of a power feeding structure in the wafer support member of FIG.
FIG. 3 is a cross-sectional view showing another example of a wafer support member according to the present invention.
FIG. 4 is a sectional view showing still another example of a wafer support member according to the present invention.
FIG. 5 is a cross-sectional view showing a wafer support member which is an example of a conventional electrode built-in body.
6 is an enlarged cross-sectional view showing an example of a power feeding structure in the wafer support member of FIG.
7 is an enlarged cross-sectional view showing another example of a power feeding structure in the wafer support member of FIG.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1, 2: Wafer support member 2, 22: Ceramic body 2a, 22a: Recess 3, 23: Installation surface 4, 24: Electrode 5, 25: Feed terminal 6: Adhesive layer

Claims

The surface of the ceramic body containing the electrode or the surface of the ceramic body joined with the resin layer containing the electrode is provided with a recess in which a part of the electrode is exposed , and the thermal expansion difference from the ceramic body is 2 × in the recess. is inserted a feeding terminal consisting of 10 -7 ^/ ° C. or less of the metal, the power feed terminal and said recess and a, Do Ri modulus of a resin-based adhesive conductive particles contained in the range of 10 to 90% by volume An electrode built-in body, which is bonded and fixed with an adhesive layer of 5 to 90 GPa .

The inner diameter of the recess is a circular hole of 1.5 to 15 mm, and the difference between the outer diameter of the insertion portion of the power supply terminal inserted into the recess and the inner diameter of the recess is 0.05 to 0.3 mm. The electrode built-in body according to claim 1, characterized in that:

On the surface of the ceramic body containing the electrode or the surface of the ceramic body joined with the resin layer containing the electrode, a recess having a circular hole with an inner diameter of 1.5 to 15 mm from which a part of the electrode is exposed is provided. While inserting the power supply terminal whose difference of the outer diameter of an insertion part and the internal diameter of the said recessed part is 0.05-0.3 mm, this power supply terminal and the said recessed part are the range of 10-90 volume% of electroconductive particle. A built-in electrode body characterized by being bonded and fixed with an adhesive layer made of a resin-based adhesive contained in 1.

The electrode built-in body according to any one of claims 1 to 3, wherein the conductive particles are made of at least one of gold, silver, copper, tin, and aluminum.

5. The electrode built-in body according to claim 1, wherein the resin forming the resin-based adhesive is made of any one of an epoxy resin, a silicon resin, and a fluororesin.

Wafer support, characterized in that the surface of the claims 1 to resin layer with a built-in surface or electrode of the ceramic body with a built-in electrodes forming the electrode-built body according to any one of claims 5 and the installation surface of the wafer Element.

The wafer support member according to claim 6 , wherein the electrode is one of an electrostatic chucking electrode and a plasma electrode.