JP3929879B2 - Wafer support member - Google Patents

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JP3929879B2
JP3929879B2 JP2002338135A JP2002338135A JP3929879B2 JP 3929879 B2 JP3929879 B2 JP 3929879B2 JP 2002338135 A JP2002338135 A JP 2002338135A JP 2002338135 A JP2002338135 A JP 2002338135A JP 3929879 B2 JP3929879 B2 JP 3929879B2
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wafer
plate
resistance heating
ceramic body
heating element
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JP2004172463A (en
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恒彦 中村
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Kyocera Corp
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Kyocera Corp
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【０００１】
【発明の属する技術分野】
本発明は、主にウェハを加熱する際に用いるウェハ加熱装置に関するものであり、例えば半導体ウェハや液晶装置あるいは回路基板等のウェハ上に薄膜を形成したり、前記ウェハ上に塗布されたレジスト液を乾燥焼き付けしてレジスト膜を形成する際に好適なウェハ支持部材に関するものである。
【０００２】
【従来の技術】
半導体製造装置の製造工程における、半導体薄膜の成膜処理、エッチング処理、レジスト膜の焼き付け処理等においては、半導体ウェハ（以下、ウェハと略す）を加熱するためのウェハ支持部材が用いられている。
【０００３】
従来の半導体製造装置は、複数のウェハを一括して加熱するバッチ式と、１枚ずつ加熱する枚様式とがあり、枚葉式には、温度制御性に優れているので、半導体素子の配線の微細化とウェハ熱処理温度の精度向上が要求されるに伴い、ウェハ支持部材が広く使用されている。
【０００４】
このようなウェハ支持部材として、例えば特許文献１、特許文献２や特許文献３には、図７に示すようなウェハ支持部材が提案されている。
【０００５】
このウェハ支持部材７１は、板状セラミックス体７２、金属ケース７９、を主要な構成要素としたもので、アルミニウム等の金属からなる有底状の金属ケース７９の開口部に、窒化物セラミックスや炭化物セラミックスからなる板状セラミックス体７２を樹脂製の断熱性の接続部材７４を介してボルト８０で固定され、その上面をウェハＷを載せる載置面７３とするとともに、板状セラミックス体７２の下面に、例えば図８に示すような同心円状の抵抗発熱体７５を備えていた。
【０００６】
さらに、抵抗発熱体７５の端子部には、給電端子７７がロウ付けされており、この給電端子７７が金属ケース７９の底部７９ａに形成されたリード線引出用の孔７６に挿通されたリード線７８と電気的に接続されていた。
【０００７】
ところで、このようなウェハ支持部材７１において、ウェハＷの表面全体に均質な膜を形成したり、レジスト膜の加熱反応状態を均質にするためには、ウェハの温度分布を均一にすることが重要である。その為、これまでウェハの面内の温度差を小さくするため、載置面７３にウェハＷ支持ピンを設け、ウェハＷを載置面７３から微小な距離浮かしたウェハ支持部材７１が特許文献４に記載されている。
【０００８】
特許文献５には、板状セラミックス体７２の周縁にウェハを取り囲む壁を設け、該壁と当接する凸状部を設け、ウェハＷ周辺の温度低下を防ぐウェハ支持部材が開示されている。
【０００９】
また、特許文献６には、図９に示すように、板状セラミックス体７２の外縁部にウェハＷと嵌合させるための突部を形成し、該突部の内側には、ウェハＷと抵触する多数の凸状体が形成することで均一な温度分布を実現するウェハ支持部材が開示されている。
【００１０】
また、特許文献７には板状セラミックス体の周辺にウェハＷの位置決めを行うガイドピンを備えることで、ウェハＷを均一な温度分布としたウェハ支持部材が開示されている。
【００１１】
更に、特許文献８にはウェハＷの支持ピンの高さが自由に調整することでウェハＷの温度分布を調整できるウェハ支持部材が開示されている。また、支持ピンにガイドピンを嵌合させたウェハ支持部材が開示されている。
【００１２】
しかし、いずれも非常に複雑で微妙な構造、制御が必要になるという課題があり、簡単な構造で温度分布を更に均一に加熱できるようなウェハ支持部材が求められていた。
【００１３】
【特許文献１】
特開２００１−２０３１５６号公報
【特許文献２】
特開２００１−３１３２４９号公報
【特許文献３】
特開２００２−７６１０２号公報
【特許文献４】
特開平１０−２２３６４２号公報
【特許文献５】
特開平１０−２２９１１４号公報
【特許文献６】
特開２００２−２３７３７５号公報
【特許文献７】
特開２００２−１８４６８３号公報
【特許文献８】
特開２００１−６８４０７号公報
【００１４】
【発明が解決しようとする課題】
近年生産効率の向上の為、ウェハサイズの大型化が進んでいるが、半導体素子自体も多様化し、必ずしも大判ウェハで製造することが生産効率の向上にはつながらず、ひとつの装置で、多種多様のウェハサイズや熱処理条件に対応可能な装置が望まれている。
【００１５】
更に、半導体素子の配線微細化に伴い使用され始めた化学増幅型レジストにおいては、ウェハの温度の均一性は勿論のこと、ウェハを熱処理装置に載置した瞬間から離脱し熱処理を終了させるまでの過渡的な温度履歴も極めて重要となり、ウェハ載置直後から概ね６０秒以内にウェハの温度が均一に安定することが望まれている。
【００１６】
しかしながら、特許文献５や特許文献６に紹介されている装置では、板状セラミックス体の周辺部の肉厚が大きく熱容量が大きいことからウェハＷ面内の過渡温度が不均一で、ウェハの面内の温度差は０．４〜１．２℃と大きく、また、板状セラミックス体の外周の放熱の影響から温度が安定するまでの応答時間が大きくなる虞があった。
【００１７】
また、特許文献８に記載のウェハ支持部材では、ウェハＷの周辺部と中心部の温度差を調整することができない虞があり、しかも支持ピンの高さを微調整することは困難であり、調整できてもウェハ表面の温度差は１℃以上と大きなものであった。
【００１８】
更に、何れのウェハ支持部材も、ウェハＷを均一に加熱したり、ウェハＷを急速に昇温したり急速に降温させる時間が大きくなる虞があった。
【００１９】
【課題を解決するための手段】
本発明は、板状セラミックス体の一方の主面または内部に複数の抵抗発熱体を備え、他方の主面にウェハを載せる載置面を備えたウェハ支持部材であって、上記載置面の周辺部に３個以上の周辺凸部を設け、該周辺凸部の内側に高さの低い内側凸部を設けるとともに、上記内側凸部の上記載置面からの突出高さは０．０５〜０．５ｍｍであり、上記内側凸部は、上記載置面の中心から上記周辺凸部に内接する内接円の直径の０．５倍の範囲内に少なくとも１個、上記内接円の直径の０．５〜１倍の範囲内に少なくとも３個以上それぞれ同心円状に配置されていることを特徴とする。
【００２０】
また、上記周辺凸部を構成する部材は上記載置面に形成した凹部に取り付けられたことを特徴とする。
【００２１】
また、上記周辺凸部は円形のセラミックスからなり、該セラミックスの熱伝導率が２０Ｗ／（ｍ・Ｋ）以上であり上記板状セラミックス体の熱伝導率の２倍より小さいことを特徴とする。
【００２２】
また、周辺凸部の一部は上記抵抗発熱体を囲む外接円の内部にあることを特徴とする。
【００２４】
また、上記抵抗発熱体の上記外接円の直径Ｄが上記板状セラミックス体の直径ＤＰの９０〜９９％であることを特徴とする。
【００２５】
【発明の実施の形態】
以下、本発明の実施の形態について説明する。
【００２６】
図１（ａ）は本発明に係るウェハ支持部材１の１例を示す断面図で、炭化珪素または窒化アルミニウムを主成分とするセラミックスからなる板状セラミックス体２の一方の主面あるいは内部に複数の抵抗発熱体５を形成し、他方の主面をウェハＷを載せる載置面３とするとともに、上記抵抗発熱体５に電気的に接続する給電部６を具備した均熱板７からなり、給電部６に給電端子１１が接続している。これらの給電部６を囲む金属ケース１９が接続部材１７を介して板状セラミックス体２の他方の主面の周辺部に固定されている。
【００２７】
また、ウェハリフトピン２５は板状セラミックス体２を貫通する孔を通してウェハＷを上下に移動させウェハＷを載置面３に載せたり降ろしたりすることができる。そして、給電部６に給電端子１１が接続し外部から電力が供給され、測温素子２７で板状セラミックス体２の温度を測定しながらウェハＷを加熱することができる。
【００２８】
尚、抵抗発熱体５を複数のゾーンに分割する場合、それぞれのゾーンの温度を独立に制御することにより、各給電部６の給電端子１１に電力を供給し、各測温素子２７の温度が各設定値となるように給電端子１１に加える電力を調整し、載置面３に載せたウェハＷの表面温度が均一となるようにしている。
【００２９】
抵抗発熱体５には、金や銀、パラジウム、白金等の材質からなる給電部６が形成され、該給電部６に給電端子１１を接触させることにより、導通が確保されている。給電端子１１と給電部６とは、導通が確保できる方法で有れば、はんだ付け、ロー付け等の手法を用いてもよい。
【００３０】
ウェハＷの載置面３に対応して円板状のウェハＷの表面を均一に加熱するにはウェハＷ周辺の雰囲気やウェハＷに対抗する壁面やガスの流れの影響を受けるが、円板状のウェハＷの表面温度をばらつかせないために、ウェハＷの周囲や上面の対抗面や雰囲気ガスの流れはウェハＷに対し中心対称となるように設計されているからである。ウェハＷを均一に加熱するにはウェハＷに対し中心対称な上記環境に合わせたウェハ支持部材１が必要で、更に載置面３を中心対称に分割し抵抗発熱体ゾーンを形成することが好ましい。
【００３１】
本発明のウェハ支持部材１は、図１（ｂ）に示すように前記板状セラミックス体２の載置面の周辺部に３個以上の周辺凸部４を設け、前記周辺凸部の内側に該周辺凸部４より高さの低い内側凸部８を設けたことを特徴とする。
【００３２】
ウェハＷは不図示のアームから移送され板状セラミックス体２の載置面３に突出したウェハリフトピン２５の上に載せられる。そしてウェハリフトピン２５が降下し載置面３上の内側凸部８にウェハＷは載せられる。ウェハＷの面内温度差を小さくするのは抵抗発熱体５を備えた板状セラミックス体２の中心位置に合わせ、板状セラミックス体２に対して正確な位置でウェハＷを載せることが重要であり、周辺凸部４をウェハガイドとして、ウェハＷは周囲が周辺凸部４と接触しながら内側凸部８で支えられることが好ましい。
【００３３】
周辺凸部４がウェハＷの横ズレを防ぐには周辺凸部４が同一円周上に少なくとも３個必要であり、周辺凸部４と接触する内接円の直径はウェハＷの直径より１．００１から１．０１倍の大きさであることが好ましい。このように配設することにより載置面３上の正確な位置にウェハＷを載せることができることから抵抗発熱体５を備えた板状セラミックス体２からの熱を均一に受けることが可能となりウェハＷの表面温度差を小さくすることができる。
【００３４】
図２（ａ）（ｂ）（ｃ）は周辺凸部４を示す拡大断面図である。図２（ａ）は円錐台形状の周辺凸部４を示し。図２（ｂ）は円柱の上に円錐台が結合した形状の周辺凸部４を示す。図２（ｃ）は周辺が湾曲面からなる周辺凸部４を示す。
【００３５】
また、前記の周辺凸部４は、板状セラミックス体２の他方の主面と同一の平面に備えることが好ましく、前記複数の周辺凸部４がウェハＷを囲む内接円の大きさは先端部で大きく、下部で小さいことが好ましい。
【００３６】
尚、特許文献５、６に記載のウェハ支持部材のようにウェハＷの横ズレを防止する円環状の凸部は板状セラミックス体２の周辺部の厚みが大きくなることから、板状セラミックス体の周辺部の熱容量が大きくなり、昇温途中の過渡時のウェハＷ面内温度差が大きいとの問題がある。しかし、本発明の板状セラミックス体２の周辺部に孤立した周辺凸部を備えることで、過渡時のウェハＷ面内の温度差の増大を防止し、しかもウェハＷの横ズレを防止できる。
【００３７】
また、ウェハＷの面内温度差を小さくするためには、板状セラミックス体２の載置面３に凹部９を形成し、その凹部９に埋設金具を接着しボルト１０で周辺凸部４を締め付けて取り付けることが好ましい。このように配設することで、載置面３の温度分布を均一に保つ事が可能となり、ウェハＷ面内の温度差を小さくできる。尚、上記凹部９に板状セラミックス体と熱伝導率の近いＦｅ−Ｎｉ−Ｃｏ合金からなる埋め込みリングで周辺凸部４をネジ止めすることもできる。
【００３８】
更に、周辺凸部４の熱伝導率は２０Ｗ／（ｍ・Ｋ）以上であり板状セラミックス体２の熱伝導率の２倍以下の熱伝導率を有することが好ましい。周辺凸部４の熱伝導率が２０Ｗ／（ｍ・Ｋ）を下回ると、周辺凸部４の周辺の温度が低下してウェハＷ面内の温度差が大きくなる虞がある。また、周辺凸部４の熱伝導率が板状セラミックス体２の熱伝導率の２倍を越えると周辺凸部４の温度が上昇し易くなりウェハＷを加熱する際の過渡時のウェハＷ面内温度差が大きくなり好ましくない。好ましくは、周辺凸部４の熱伝導率を３０Ｗ／（ｍ・Ｋ）以上とし、板状セラミックス体２の熱伝導率の１倍以下とすると、周辺凸部４の周辺の温度低下や上昇を小さくすることができる。
【００３９】
尚、ウェハＷの表面温度差を小さくするには周辺凸部４の一部は板状セラミックス体２の抵抗発熱体５を囲む外接円の内部にあることが好ましい。このような配置とすると抵抗発熱体５によりウェハＷの表面積より広い範囲の載置面３を加熱することが可能となり、ウェハＷの面内の温度差が小さくなり好ましい。
【００４０】
また、周辺凸部４は平面視したときに円形状のセラミックスであることが好ましく、さらに直径５〜３０ｍｍであることが好ましい。直径５ｍｍを下回ると載置面３に精度良く固定することが困難であり、直径３０ｍｍを越えるとウェハＷの面内温度差が大きくなる虞がある。好ましくは直径１０〜２０ｍｍである。
【００４１】
また、周辺凸部４の側面の表面粗さは、Ｒａで０．１〜５μｍであることが好ましい。周辺凸部４の側面はウェハＷの端面或いは端面のエッジ部と接触するが、Ｒａが０．１〜５μｍであればウェハＷと接触してもウェハＷのエッジが欠損したりパーティクルを発生する虞が少ない。Ｒａが５μｍ或いはＲｍａｘが１０μｍを越えると、ウェハＷと周辺凸部４の側面が接触した際にウェハＷのエッジが欠損したり周辺凸部４の表面が欠損しパーティクルを発生する虞がある。
【００４２】
上記周辺凸部４によりウェハＷの周辺をガイドすることにより載置面３内方向のウェハＷ位置を正確に固定することができる。
【００４３】
そして、載置面３とウェハＷの間隔は内側凸部８でウェハＷを支持するが、ウェハＷ面と載置面３の間隔をできるだけ均一にするためには、内側凸部８が載置面３に均等に配設されていることが好ましい。内側凸部８は載置面３の中心から周辺凸部４に内接する内接円の直径の０．５倍の範囲内に少なくとも１個、前記内接円の直径の０．５〜１倍の範囲内に少なくとも３個配置されているとウェハＷ表面の変形が小さく、むら無く支持することが可能となり、ウェハＷの自重による変形や反りを防止することができることから、ウェハＷ面内の温度差が小さくなり好ましい。
【００４４】
また、ウェハＷは内側凸部８を介して載置面３と一定の間隔で離間させることにより、載置面３と直接接触した場合の片あたりによるウェハＷ面内の温度バラツキの発生を防止できる。そして、載置面３上のガスを介してウェハＷを加熱することによりウェハＷ面内の温度を均一に昇温させたり、ウェハＷ面内の温度を均一に保持することができる。
【００４５】
ウェハＷと載置面３の間隔を決める内側凸部８の載置面からの突出高さは０．０５〜０．５ｍｍが適切であり、０．０５ｍｍを下回ると載置面３の温度がウェハＷに急激に伝わりウェハＷ面内の温度差を大きくする。また、０．５ｍｍを越えると載置面３からウェハＷへ伝わる熱の伝わりが遅くなりウェハＷ面内の温度差を大きくする。更に好ましくは０．０７〜０．２ｍｍである。
【００４６】
また、上記内側凸部は、載置面の中心から上記周辺凸部に内接する内接円の直径の０．５倍の範囲内に少なくとも１個、前記内接円の直径の０．５〜１倍の範囲内に少なくとも３個以上それぞれ同心円状に配置されているとウェハＷを平坦端に固定しウェハＷの表面の温度差を小さくできることから好ましい。更に好ましくは、内接円の直径の０．５倍の範囲内に少なくとも３個、前記内接円の直径の０．５〜１倍の範囲内に少なくとも５個以上あるとウェハＷ面の変形が更に小さくなり、ウェハＷの面内の温度差を０．４℃以下に小さくすることが可能となる。
【００４７】
図３（ａ）は本発明のウェハ支持部材１で、板状セラミックス体２の一方の主面に複数の抵抗発熱体ゾーン４を備え、中心部に円形の抵抗発熱体ゾーン４ａと、その外側に同心円の２つの円環内に抵抗発熱体ゾーン４ｂｃと抵抗発熱体ゾーン４ｄｇとを備える各抵抗発熱体ゾーン４の配置例を示す。
【００４８】
図３（ｂ）は、本発明のウェハ支持部材１の中心部の円形の抵抗発熱体ゾーン４ａと、その外側に円環４ｂｃを２等分した扇状の２個の抵抗発熱体ゾーン４ｂ、４ｃを備え、更にその外側の円環４ｄｇ内にそれぞれ対抗する位置で円環を円周方向に４等分した扇状の４個の抵抗発熱体ゾーン４ｄ、４ｅ、４ｆ、４ｇからなるウェハ支持部材１であり、ウェハＷの表面温度がより均一となり好ましい。
【００４９】
上記ウェハ支持部材１の各抵抗発熱体ゾーン４ａ〜４ｇは独立して発熱でき、各抵抗発熱体ゾーン４ａ〜４ｇに対応して抵抗発熱体５ａ〜５ｇを備えている。
【００５０】
尚、円環状の抵抗発熱体ゾーン４ｂｃ、４ｄｇはそれぞれ放射方向に２分割、４分割したが、これに限るものではない。
【００５１】
図３（ｂ）の抵発熱体ゾーン４ｂ、４ｃの境界線は直線であるが、必ずしも直線である必要はなく、波線であってよい。抵抗発熱体ゾーン４ｂ、４ｃが板状セラミックス体２の中心に対して中心対称であることが好ましい。
【００５２】
同様に、抵抗発熱体ゾーンの４ｄと４ｅ、４ｅと４ｆ、４ｆと４ｇ、４ｇと４ｄとのそれぞれの境界線も必ずしも直線である必要はなく、それぞれの抵抗発熱体４ｄから４ｇは、板状セラミックス体２の中心に対し中心対称であることが好ましい。
【００５３】
上記の各抵抗発熱体５は、印刷法等で作製し、１〜５ｍｍの巾で厚みが５〜５０μｍで形成することが好ましい。一度に印刷する印刷面が大きくなると、印刷面の左右や前後でスキージとスクリーンとの間の圧力の違いから印刷厚みが一定とならない虞が生じる。特に、抵抗発熱体５の大きさが大きくなると、抵抗発熱体５の左右前後の厚みが異なり設計した発熱量がバラツク虞があった。発熱量がバラツクとウェハＷの面内温度差が大きくなり好ましくない。この抵抗発熱体の厚みのバラツキから生じる温度バラツキを防ぐには、一つの抵抗発熱体からなる外径の大きな個々の抵抗発熱体５を分割することが有効である事が判明した。
【００５４】
そこで、ウェハＷ載置面３の中心部を除く同心円環状の抵抗発熱体ゾーンは左右に２分割し、更に大きな円環状の抵抗発熱体ゾーンは４分割することで抵抗発熱体ゾーンにある抵抗発熱体５の印刷する大きさを小さくすることができることから、抵抗発熱体５の各部の厚みを均一にすることができ、更にウェハＷの前後左右の微妙な温度差を補正しウェハＷの表面温度を均一にすることができる。
【００５５】
また、図４に示すように、前記抵抗発熱体５の外接円Ｃの直径Ｄが前記板状セラミックス体２の直径ＤＰの９０〜９９％であることが好ましい。抵抗発熱体５の外接円Ｃの直径Ｄが板状セラミックス体２の直径ＤＰの９０％より小さいと、ウェハを急速に昇温したり急速に降温させる時間が大きくなりウェハＷの温度応答特性が劣る。
【００５６】
また、ウェハＷの周辺部の温度を下げないようウェハＷの表面温度を均一に加熱するには、直径ＤはウェハＷの直径の１．０２〜１．１倍程度が好ましいことから、ウェハＷの大きさに対して板状セラミックス体２の直径ＤＰが大きくなり、均一に加熱できるウェハＷの大きさが板状セラミックス体２の直径ＤＰに比較して小さくなり、ウェハＷを加熱する投入電力に対しウェハＷを加熱する加熱効率が悪くなる。更に、板状セラミックス体２が大きくなることからウェハ製造装置の設置面積が大きくなり、最小の設置面積で最大の生産を行う必要がある半導体製造装置の設置面積に対する稼働率を低下させ好ましくない。
【００５７】
抵抗発熱体５の外接円Ｃの直径Ｄが板状セラミックス体２の直径ＤＰの９９％より大きいと接触部材１７と抵抗発熱体５の外周との間隔が小さく抵抗発熱体５の外周部から熱が接触部材１７に不均一に流れ、特に、外周部の外接円Ｃに接する円弧状パターン５１が存在しない部分からも熱が流れ、外周部の円弧状パターン５１が板状セラミックス体２の中心部へ曲がっていることから抵抗発熱体５を囲む外接円Ｃに沿って円弧状パターン５１が欠落する部分Ｐの温度が低下しウェハＷの面内温度差を大きくする虞がある。より好ましくは、抵抗発熱体５の外接円Ｃの直径Ｄが板状セラミックス体２の直径ＤＰの９２〜９７％である。
【００５８】
また、図１（ａ）に示す様に板状セラミックス体２と金属ケース１９の外形が略同等で板状セラミックス体２を下から金属ケース１９が支える場合、ウェハＷの面内の温度差を小さくするには、抵抗発熱体５の外接円Ｃの直径Ｄが板状セラミックス体２の直径ＤＰの９２〜９５％であり、更に好ましくは９３〜９５％である。
【００５９】
一方、図６に示す様な板状セラミックス体２の外周面を覆うように金属ケースが接続した場合には、抵抗発熱体５の外接円Ｃの直径Ｄが板状セラミックス体２の直径ＤＰの９５〜９８％が好ましく、更に好ましくは９６〜９７％である。
【００６０】
板厚が１〜７ｍｍの板状セラミックス体２の一方の主面側を、ウェハを載せる載置面３とするとともに、上記板状セラミックス体２の下面に抵抗発熱体５を備えたウェハ支持部材１において、上記抵抗発熱体５の厚みが５〜５０μｍであるとともに、上記抵抗発熱体を囲む外接円Ｃの面積に対し、上記外接円Ｃに占める抵抗発熱体５の面積の比率が５〜５０％であることが好ましい。
【００６１】
即ち、抵抗発熱体５を囲む外接円Ｃの面積に対し、外接円Ｃ内に占める抵抗発熱体５の面積の比率を５％未満とすると、抵抗発熱体５の相対向する対向領域において、対向領域の対向間隔Ｓ１が大きくなり過ぎることから、抵抗発熱体５のない間隔Ｓ１に対応した載置面３の表面温度が他の部分と比較して小さくなり、載置面３の温度を均一にすることが難しいからであり、逆に抵抗発熱体５を囲む外接円Ｃの面積に対し、外接円Ｃ内に占める抵抗発熱体５の面積の比率が５０％を超えると、板状セラミックス体２と抵抗発熱体５との間の熱膨張差を３．０×１０−６／℃以下に近似させたとしても、両者の間に作用する熱応力が大きすぎることから、板状セラミックス体２は変形し難いセラミックス焼結体からなるものの、その板厚ｔが１ｍｍ〜７ｍｍと薄いことから抵抗発熱体５を発熱させると、載置面３側が凹となるように板状セラミックス体２に反りが発生し、その結果、ウェハＷの中心部の温度が周縁よりも小さくなり、温度バラツキが大きくなる恐れがあるからである。
【００６２】
なお、好ましくは、抵抗発熱体５を囲む外接円Ｃの面積に対し、外接円Ｃ内に占める抵抗発熱体５の面積の比率を１０％〜３０％、さらには１５％〜２５％とすることが好ましい。
【００６３】
さらに、このような効果を効率良く発現させるには、抵抗発熱体５の膜厚を５〜５０μｍとすることが好ましい。
【００６４】
抵抗発熱体５の膜厚が５μｍを下回ると、抵抗発熱体５をスクリーン印刷法で膜厚を均一に印刷することが困難となるからであり、また、抵抗発熱体５の厚みが５０μｍを越えると、外接円Ｐ１に対し、抵抗発熱体５の占める面積の比率を５０％以下としても抵抗発熱体５の厚みが大きく、抵抗発熱体５の剛性が大きくなり、板状セラミックス体２の温度変化により抵抗発熱体５の伸び縮みによる影響で板状セラミックス体２が変形する虞がある。また、スクリーン印刷で均一の厚みに印刷することが難しくウェハＷの表面の温度差が大きくなったりする虞があるからである。なお、好ましい抵抗発熱体５の厚みは１０〜３０μｍとすることが良い。
【００６５】
本発明の抵抗発熱体５のパターン形状としては、図３に示したような折り返しパターン、あるいは図４や図５に示すような複数のブロックに分割され、個々のブロックが円弧状のパターンと直線状のパターンとからなる渦巻き状やジグザクな折り返し形状をしたもので、本願発明のウェハ支持部材１はウェハＷを均一に加熱することが重要であることから、これらのパターン形状は帯状の抵抗発熱体５の各部の密度が均一なことが好ましい。図４に示すように板状セラミックス体２の外周部に位置する前記抵抗発熱体５ｄ、５ｅ、５ｄ、５ｆは板状セラミックス体２の中心から遠い部位は同心円状をした円弧状パターン５１とこれらと連続して繋がっている連結パターン５２からなることが好ましい。ただし、図８に示すような、板状セラミックス体７２の中心から放射方向に見て、抵抗発熱体２５の間隔が密な部分と粗な部分が交互に現れる抵抗発熱体パターンでは、粗な部分に対応するウェハＷの表面温度は小さく、密な部分に対応するウェハＷの温度は大きくなり、ウェハＷの表面の全面を均一に加熱することはできないことから好ましくない。
【００６６】
また、抵抗発熱体５を複数のブロックに分割する場合、それぞれのブロックの温度を独立に制御することにより、載置面３上のウェハＷを均一に加熱することが好ましい。
【００６７】
抵抗発熱体５は、導電性の金属粒子にガラスフリットや金属酸化物を含む電極ペーストを印刷法で板状セラミックス体２に印刷、焼き付けしたもので、金属粒子としては、Ａｕ、Ａｇ、Ｃｕ、Ｐｄ、Ｐｔ、Ｒｈの少なくとも一種の金属を用いることが好ましく、またガラスフリットとしては、Ｂ、Ｓｉ、Ｚｎを含む酸化物からなり、板状セラミックス体２の熱膨張係数より小さな４．５×１０−６／℃以下の低膨張ガラスを用いることが好ましく、さらに金属酸化物としては、酸化珪素、酸化ホウ素、アルミナ、チタニアから選ばれた少なくとも一種を用いることが好ましい。
【００６８】
ここで、抵抗発熱体５を形成する金属粒子として、Ａｕ、Ａｇ、Ｃｕ、Ｐｄ、Ｐｔ、Ｒｈの少なくとも一種の金属を用いるのは、電気抵抗が小さいからである。
【００６９】
抵抗発熱体５を形成するガラスフリットとして、Ｂ、Ｓｉ、Ｚｎを含む酸化物からなり、抵抗発熱体５を構成する金属粒子の熱膨張係数が板状セラミックス体２の熱膨張係数より大きいことから、抵抗発熱体５の熱膨張係数を板状セラミックス体２の熱膨張係数に近づけるには、板状セラミックス体２の熱膨張係数より小さな４．５×１０−６／℃以下の低膨張ガラスを用いることが好ましいからである。
【００７０】
また、抵抗発熱体５を形成する金属酸化物としては、酸化珪素、酸化ホウ素、アルミナ、チタニアから選ばれた少なくとも一種を用いるのは、抵抗発熱体５の中の金属粒子と密着性が優れ、しかも熱膨張係数が板状セラミックス体２の熱膨張係数と近く、板状セラミック体２との密着性も優れるからである。
【００７１】
ただし、抵抗発熱体５に対し、金属酸化物の含有量が８０％を超えると、板状セラミックス体２との密着力は増すものの、抵抗発熱体５の抵抗値が大きくなり好ましくない。その為、金属酸化物の含有量は６０％以下とすることが良い。
【００７２】
そして、導電性の金属粒子とガラスフリットや金属酸化物からなる抵抗発熱体５は、板状セラミック体２との熱膨張差が３．０×１０-6／℃以下であるものを用いることが好ましい。
【００７３】
即ち、抵抗発熱体５と板状セラミックス体２との熱膨張差を０．１×１０−６／℃とすることは製造上難しく、逆に抵抗発熱体５と板状セラミックス体２との熱膨張差が３．０×１０−６／℃を超えると、抵抗発熱体５を発熱させた時、板状セラミックス体２との間に作用する熱応力によって、載置面３側が凹状に反る虞があるからである。
【００７４】
更に、抵抗発熱体５への給電方法については、有底の金属ケース１９に設置した給電端子１１を板状セラミックス体２の表面に形成した給電部６にバネ（不図示）で押圧することにより接続を確保し給電する。これは、２〜５ｍｍの厚みの板状セラミックス体２に金属からなる端子部を埋設して形成すると、該端子部の熱容量により均熱性が悪くなるからである。そのため、本発明のように、給電端子１１をバネで押圧して電気的接続を確保することにより、板状セラミックス体２とその有底の金属ケース１９の間の温度差による熱応力を緩和し、高い信頼性で電気的導通を維持できる。さらに、接点が点接触となるのを防止するため、弾性のある導体を中間層として挿入しても構わない。この中間層は単に箔状のシートを挿入するだけでも効果がある。そして、給電端子１１の給電部６側の径は、１．５〜５ｍｍとすることが好ましい。
【００７５】
また、板状セラミックス体２の温度は、板状セラミックス体２にその先端が埋め込まれた熱電対２７により測定する。熱電対２７としては、その応答性と保持の作業性の観点から、外径０．８ｍｍ以下のシース型の熱電対２７を使用することが好ましい。この熱電対２７の先端部は、板状セラミックス体２に孔が形成され、この中に設置された固定部材により孔の内壁面に押圧固定することが測温の信頼性を向上させるために好ましい。同様に素線の熱電対やＰｔ等の測温抵抗体を埋設して測温を行うことも可能である。
【００７６】
また、図１（ａ）では板状セラミックス体２の他方の主面３に抵抗発熱体５のみを備えたウェハ支持部材１について示したが、本発明は、主面３と抵抗発熱体５との間に静電吸着用やプラズマ発生用としての電極を埋設したものであっても良いことは言うまでもない。
【００７７】
更に詳細な構成について説明する。
【００７８】
図１（ａ）は本発明に係るウェハ支持部材の一例を示す断面図で、板厚ｔが１〜７ｍｍ、１００〜２００℃のヤング率が２００〜４５０ＭＰａである板状セラミックス体２の一方の主面を、ウェハＷを載せる載置面３とするとともに、他方の主面に抵抗発熱体５を形成し、この抵抗発熱体５に電気的に接続する給電部６を備えたものである。
【００７９】
１００〜２００℃のヤング率が２００〜４５０ＭＰａである板状セラミックス体２の材質としては、アルミナ、窒化珪素、サイアロン、窒化アルミニウムを用いることができ、この中でも特に窒化アルミニウムは５０Ｗ／（ｍ・Ｋ）以上、さらには１００Ｗ／（ｍ・Ｋ）以上の高い熱伝導率を有するとともに、フッ素系や塩素系等の腐食性ガスに対する耐蝕性や耐プレズマ性にも優れることから、板状セラミックス体２の材質として好適である。
【００８０】
板状セラミックス体２の厚みは、２〜５ｍｍとすると更に好ましい。板状セラミックス体２の厚みが２ｍｍより薄いと、板状セラミックス体２の強度がなくなり抵抗発熱体５の発熱による加熱時、ガス噴射口２４らの冷却エアーを吹き付けた際に、冷却時の熱応力に耐えきれず、板状セラミックス体２にクラックが発生する虞があるからである。また、板状セラミックス体２の厚みが５ｍｍを越えると、板状セラミックス体２の熱容量が大きくなるので加熱および冷却時の温度が安定するまでの時間が長くなる虞がある。
【００８１】
板状セラミックス体２は、有底の金属ケース１９開口部の外周にボルト１６を貫通させ、板状セラミックス体２と有底の金属ケース１９が直接当たらないように、リング状の接触部材１７を介在させ、有底の金属ケース１９側より弾性体１８を介在させてナット２０を螺着することにより弾性的に固定している。これにより、板状セラミックス体２の温度が変動した場合に有底の金属ケース１９が変形しても、上記弾性体１８によってこれを吸収し、これにより板状セラミックス体２の反りを抑制し、ウェハ表面に、板状セラミックス体２の反りに起因する温度ばらつきが発生することを防止できるようになる。
【００８２】
リング状の接触部材１７の断面は多角形や円形の何れでも良いが、板状セラミックス体２と接触部材１７が平面で接触する場合において、板状セラミックス体２と接触部材１７の接する接触部の巾は０．１ｍｍ〜１３ｍｍであれば、板状セラミックス体２の熱が接触部材１７を介して有底の金属ケース１９に流れる量を小さくすることができる。そして、ウェハＷの面内の温度差が小さくウェハＷを均一に加熱することができる。好ましくは０．１〜８ｍｍである。接触部材１７の接触部の巾が０．１ｍｍ以下では、板状セラミックス体２と接触固定した際に接触部が変形し、接触部材が破損する虞がある。また、接触部材１７の接触部の巾が１３ｍｍを越える場合には、板状セラミックス体２の熱が接触部材に流れ、板状セラミックス体２の周辺部の温度が低下しウェハＷを均一に加熱することが難しくなる。好ましくは接触部材１７と板状セラミックス体２の接触部の巾は０．１ｍｍ〜８ｍｍであり、更に好ましくは０．１〜２ｍｍである。
【００８３】
また、接触部材１７の熱伝導率は板状セラミックス体２の熱伝導率より小さいことが好ましい。接触部材１７の熱伝導率が板状セラミックス体２の熱伝導率より小さければ板状セラミックス体２に載せたウェハＷ面内の温度分布を均一に加熱することができると共に、板状セラミックス体２の温度を上げたり下げたりする際に、接触部材１７との熱の伝達量が小さく有底の金属ケース１９との熱的干渉が少なく、迅速に温度を変更することが容易となる。
【００８４】
接触部材１７の熱伝導率が板状セラミックス体２の熱伝導率の１０％より小さいウェハ支持部材１では、板状セラミックス体２の熱が有底の金属ケース１９に流れ難く、雰囲気ガス（ここでは空気）による伝熱や輻射伝熱により流れる熱が多くなり逆に効果が小さい。
【００８５】
接触部材１７の熱伝導率が板状セラミックス体２の熱伝導率より大きい場合には、板状セラミックス体２の周辺部の熱が接触部材１７を介して有底の金属ケース１９に流れ、有底の金属ケース１９を加熱すると共に、板状セラミックス体２の周辺部の温度が低下しウェハＷ面内の温度差が大きくなり好ましくない。また、有底の金属ケース１９が加熱されることからガス噴射口２４からエアを噴射し板状セラミックス体２を冷却しようとしても有底の金属ケース１９の温度が高いことから冷却する時間が大きくなったり、一定温度に加熱する際に一定温度になるまでの時間が大きくなる虞があった。
【００８６】
一方、前記接触部材１７を構成する材料としては、小さな接触部を保持するために、接触部材のヤング率は１ＧＰａ以上が好ましく、更に好ましくは１０ＧＰａ以上である。このようなヤング率とすることで、接触部の巾が０．１ｍｍ〜８ｍｍと小さく、板状セラミックス体２を有底の金属ケース１９に接触部材１７を介してボルト１６で固定しても、接触部材１７が変形することが無く、板状セラミックス体２が位置ズレしたり平行度が変化したりすることなく、精度良く保持することができる。
尚、特開２００１−３１３２４９号公報に記載のような、フッ素系樹脂やガラス繊維を添加した樹脂からなる接触部材では得られない精度を達成することができる。
【００８７】
前記接触部材１７の材質としては鉄とカーボンからなる炭素鋼やニッケル、マンガン、クロムを加えた特殊鋼等の金属がヤング率が大きく好ましい。また、熱伝導率の小さな材料としては、ステンレス鋼やＦｅ―Ｎｉ−Ｃｏ系合金の所謂コバールが好ましく、板状セラミックス体２の熱伝導率より小さくなるように接触部材１７の材料を選択することが好ましい。
【００８８】
更に、接触部材１７と板状セラミックス体２との接触部を小さく、且つ接触部が小さくても接触部が欠損しパーティクルを発生する虞が小さく安定な接触部を保持できるために、板状セラミックス体２に垂直な面で切断した接触部材１７の断面は多角形より円形が好ましく、断面の直径１ｍｍ以下の円形のワイヤを接触部材１７として使用すると板状セラミックス体２と有底の金属ケース１９の位置が変化することなくウェハＷの表面温度を均一にしかも迅速に昇降温することが可能である。
【００８９】
以上、接触部材１７の構成と板状セラミックス体２と抵抗発熱体５の配設の関係について説明したが、これらの配設は、前記周辺凸部４の一部が抵抗発熱体５を囲む直径Ｄの内側に存在することから、周辺凸部４のウェハＷ面内温度に対する影響を考慮していることは言うまでもない。
【００９０】
次に、有底の金属ケース１９は側壁部２２と底面２１を有し、板状セラミックス体２はその有底の金属ケース１９の開口部を覆うように設置してある。また、有底の金属ケース１９には冷却ガスを排出するための孔２３が施されており、板状セラミックス体２の抵抗発熱体５に給電するための給電部６に導通するための給電端子１１，板状セラミックス体２を冷却するためのガス噴射口２４、板状セラミックス体２の温度を測定するための熱電対２７を設置してある。
【００９１】
なお、有底の金属ケース１９の深さは１０〜５０ｍｍで、底面２１は、板状セラミックス体２から１０〜５０ｍｍの距離に設置することが望ましい。更に好ましくは２０〜３０ｍｍである。これは、板状セラミックス体２と有底の金属ケース１９相互の輻射熱により載置面３の均熱化が容易となると同時に、外部との断熱効果があるので、載置面３の温度が一定で均一な温度となるまでの時間が短くなるためである。
【００９２】
そして、有底の金属ケース１９内に昇降自在に設置されたリフトピン２５により、ウェハＷを載置面３上に載せたり載置面３より持ち上げたりといった作業がなされる。そして、ウェハＷは、ウェハ支持ピン８により載置面３から浮かした状態で保持され、片当たり等による温度バラツキを防止するようにしている。
【００９３】
また、このウェハ加熱装置１によりウェハＷを加熱するには、搬送アーム（不図示）にて載置面３の上方まで運ばれたウェハＷをリフトピン２５にて支持したあと、リフトピン２５を降下させてウェハＷを載置面３上に載せる。
【００９４】
次に、ウェハ支持部材１をレジスト膜形成用として使用する場合は、板状セラミックス体２の主成分を炭化珪素にすると、大気中の水分等と反応してガスを発生させることもないため、ウェハＷ上へのレジスト膜の貼付に用いたとしても、レジスト膜の組織に悪影響を与えることがなく、微細な配線を高密度に形成することが可能である。この際、焼結助剤に水と反応してアンモニアやアミンを形成する可能性のある窒化物を含まないようにすることが必要である。
【００９５】
なお、板状セラミックス体２を形成する炭化珪素質焼結体は、主成分の炭化珪素に対し、焼結助剤として硼素（Ｂ）と炭素（Ｃ）を添加したり、もしくはアルミナ（Ａｌ2Ｏ3）イットリア（Ｙ2Ｏ3）のような金属酸化物を添加して十分混合し、平板状に加工したのち、１９００〜２１００℃で焼成することにより得られる。炭化珪素はα型を主体とするものあるいはβ型を主体とするもののいずれであっても構わない。
【００９６】
一方、炭化珪素質焼結体を板状セラミックス体２として使用する場合、半導電性を有する板状セラミックス体２と抵抗発熱体５との間の絶縁を保つ絶縁層としては、ガラス又は樹脂を用いることが可能であり、ガラスを用いる場合、その厚みが１００μｍ未満では耐電圧が１．５ｋＶを下回り絶縁性が保てず、逆に厚みが４００μｍを越えると、板状セラミックス体２を形成する炭化珪素質焼結体や窒化アルミニウム質焼結体との熱膨張差が大きくなり過ぎるために、クラックが発生して絶縁層として機能しなくなる。その為、絶縁層としてガラスを用いる場合、絶縁層４の厚みは１００〜４００μｍの範囲で形成することが好ましく、望ましくは２００μｍ〜３５０μｍの範囲とすることが良い。
【００９７】
さらに、板状セラミックス体２の載置面３と反対側の主面は、ガラスや樹脂からなる絶縁層４との密着性を高める観点から、平面度２０μｍ以下、面粗さを中心線平均粗さ（Ｒａ）で０．１μｍ〜０．５μｍに研磨しておくことが好ましい。
【００９８】
また、板状セラミックス体２を、窒化アルミニウムを主成分とする焼結体で形成する場合は、主成分の窒化アルミニウムに対し、焼結助剤としてＹ2Ｏ3やＹｂ2Ｏ3等の希土類元素酸化物と必要に応じてＣａＯ等のアルカリ土類金属酸化物を添加して十分混合し、平板状に加工した後、窒素ガス中１９００〜２１００℃で焼成することにより得られる。板状セラミックス体２に対する抵抗発熱体５の密着性を向上させるために、ガラスからなる絶縁層を形成することもある。ただし、抵抗発熱体５の中に十分なガラスを添加し、これにより十分な密着強度が得られる場合は、省略することが可能である。
【００９９】
この絶縁層を形成するガラスの特性としては、結晶質又は非晶質のいずれでも良く、耐熱温度が２００℃以上でかつ０℃〜２００℃の温度域における熱膨張係数が板状セラミックス体２を構成するセラミックスの熱膨張係数に対し−５×１０-7／℃〜＋５×１０-7／℃の範囲にあるものを適宜選択して用いることが好ましい。即ち、熱膨張係数が前記範囲を外れたガラスを用いると、板状セラミックス体２を形成するセラミックスとの熱膨張差が大きくなりすぎるため、ガラスの焼付け後の冷却時においてクラックや剥離等の欠陥が生じ易いからである。
【０１００】
なお、ガラスからなる絶縁層を板状セラミックス体２上に被着する手段としては、前記ガラスペーストを板状セラミックス体２の中心部に適量落とし、スピンコーティング法にて伸ばして均一に塗布するか、あるいはスクリーン印刷法、ディッピング法、スプレーコーティング法等にて均一に塗布したあと、ガラスペーストを６００℃以上の温度で焼き付けすれば良い。また、絶縁層としてガラスを用いる場合、予め炭化珪素質焼結体又は窒化アルミニウム質焼結体からなる板状セラミックス体２を８５０〜１３００℃程度の温度に加熱し、絶縁層を被着する表面を酸化処理しておくことで、ガラスからなる絶縁層との密着性を高めることができる。
【０１０１】
【実施例】
（実施例 １）
まず、窒化アルミニウム粉末に対し、重量換算で１．0質量％の酸化イットリウムを添加し、さらにイソプロピルアルコールとウレタンボールを用いてボールミルにより４８時間混練することにより窒化アルミニウムのスラリーを製作した。
【０１０２】
次に、窒化アルミニウムのスラリーを２００メッシュに通し、ウレタンボールやボールミル壁の屑を取り除いた後、防爆乾燥機にて１２０℃で２４時間乾燥した。
【０１０３】
次いで、得られた窒化アルミニウム粉末にアクリル系のバインダーと溶媒を混合して窒化アルミニムのスリップを作製し、ドクターブレード法にて窒化アルミニムのグリーンシートを複数枚製作した。
【０１０４】
そして、得られた窒化アルミニウムのグリーンシートを複数枚積層熱圧着にて積層体を形成した。
【０１０５】
しかる後、積層体を非酸化性ガス気流中にて５００℃の温度で５時間脱脂を施した後、非酸化性雰囲気にて１９００℃の温度で５時間の焼成を行い各種の熱伝導率を有する板状セラミックス体を製作した。
【０１０６】
そして、窒化アルミニウム焼結体に研削加工を施し、板厚３ｍｍ、直径３３０ｍｍの円盤状をした板状セラミックス体と板厚４ｍｍで周辺部に円環状の凸部を備え直径３０１ｍｍの中心部の板厚が３ｍｍの板状セラミックス体を作製した。更に中心から６０ｍｍの同心円上に均等に３箇所貫通孔を形成した。貫通口径は、４ｍｍとした。
【０１０７】
次いで板状セラミックス体の上に抵抗発熱体５を被着するため、導電材としてＡｕ粉末とＰｄ粉末と、前記同様の組成からなるバインダーを添加したガラスペーストを混練して作製した導電体ペーストをスクリーン印刷法にて所定のパターン形状に印刷したあと、１５０℃に加熱して有機溶剤を乾燥させ、さらに５５０℃で３０分間脱脂処理を施したあと、７００〜９００℃の温度で焼き付けを行うことにより、厚みが５０μｍの抵抗発熱体５を形成した。
【０１０８】
抵抗発熱体ゾーンの配置は、中心部に円形の１つに抵抗発熱体ゾーンを形成し、その外側の円環を同等の２つの抵抗発熱体ゾーンに分割し、更にその外側に円環を４つの抵抗発熱体ゾーンに分割した計７個の抵抗発熱体ゾーン構成とした。
【０１０９】
また、有底の金属ケースの底面の厚みは２．０ｍｍのアルミニウムと側壁部を構成する厚み１．０ｍｍのアルミニウムからなり、底面に、ガス噴射口、熱電対、導通端子を所定の位置に取り付けた。また、底面から板状セラミックス体までの距離は２０ｍｍとした。
【０１１０】
その後、前記有底の金属ケースの開口部に、板状セラミックス体を重ね、その外周部にボルトを貫通させ、板状セラミックス体と有底の金属ケースが直接当たらないように、リング状の接触部材を介在させ、接触部材側より弾性体を介在させてナットを螺着して弾性的に固定することによりウェハ支持部材とした。
【０１１１】
尚、接触部材１７の断面は円形状で、リング状とした。円形状の断面の大きさは、直径１ｍｍとした。また、接触部材の材質はＳＵＳ３０４、炭素鋼を用いた。
【０１１２】
その後、載置面の中心に１個の内側凸部と中心から８５ｍｍの距離に３個の内側凸部を取り付け、中心から１３０ｍｍの距離に５個の内側凸部を取り付けたものを試料Ｎｏ.１、２とした。
【０１１３】
試料Ｎｏ．１は板状セラミックス体２の周辺部に周辺凸部を３箇所等配に取り付けた。また、試料Ｎｏ．２は板状セラミックス体の周辺部は載置面より１ｍｍ凸に形成された従来のウェハ支持部材である。
【０１１４】
作製したウェハ支持部材の評価は、測温抵抗体が２９箇所に埋設された直径３００ｍｍの測温用ウェハを用いて行った。夫々のウェハ支持部材に電源を取り付け２５℃から２００℃まで５分間でウェハＷを昇温し、ウェハＷの温度を２００℃に設定してからウェハＷの平均温度が２００℃±０．５℃の範囲で一定となるまでの時間保持した。そして、ウェハリフトピンを上昇させてウェハＷを取り外し、ウェハＷを室温に冷却した後再びウェハ支持部材に載せウェハＷの平均温度が２００℃±０．５℃となるまでの時間を応答時間として測定した。その後３０分間ウェハＷ平均温度を２００℃に保持した時点でのウェハＷ面内の温度差を測定した。
【０１１５】
それぞれの結果は表１に示す通りである。
【０１１６】
【表１】

Figure 0003929879
【０１１７】
載置面の周辺に孤立した周辺凸部４を設け、内側凸部４を備えた本願発明のウェハ支持部材１はウェハＷ面内の温度差は０．３５℃と小さく、しかも応答時間は３５秒と小さく優れた特性を示す事が分った。
【０１１８】
それに対して、載置面の周辺部に円環状の凸部を備えた試料Ｎｏ.２はウェハＷ面内の温度差は０．４１℃とやや小さいが、応答時間が６３秒と大きく、均一なレジスト膜を作製することが出来なかった。
【０１１９】
また、内側凸部のない試料Ｎｏ.３は、ウェハＷ面内の温度差が０．６３℃と大きく、しかも応答時間も４７秒とやや大きかった。
【０１２０】
（実施例 ２）
実施例１と同様に板状セラミックス体を作製した。
【０１２１】
そして、窒化アルミニウム焼結体に研削加工を施し、板厚３ｍｍ、直径３３０ｍｍの円盤状をした板状セラミックス体２を複数枚製作し、更に中心から６０ｍｍの同心円上に均等に３箇所貫通孔を形成した。貫通口径は、４ｍｍとした。
【０１２２】
次いで板状セラミックス体２の上に抵抗発熱体５を被着するため、導電材としてＡｕ粉末とＰｄ粉末と、前記同様の組成からなるバインダーを添加したガラスペーストを混練して作製した導電体ペーストをスクリーン印刷法にて所定のパターン形状に印刷したあと、１５０℃に加熱して有機溶剤を乾燥させ、さらに５５０℃で３０分間脱脂処理を施したあと、７００〜９００℃の温度で焼き付けを行うことにより、厚みが５０μｍの抵抗発熱体５を形成した。抵抗発熱体５のパターン配置は、中心部から放射状に円と円環状に分割し、中心部に円形の１つにパターンを形成し、その外側の円環状の部分に２つにパターンを形成し、更に最外周に４つのパターンの計７個のパターン構成とした。そして、最外周の４つのパターンの外接円Ｃの直径を３１０ｍｍとして、板状セラミックスの直径を変えて作製した。しかるのち抵抗発熱体５に給電部６をロウ付けし固着させることにより、板状セラミックス体２を製作した。
【０１２３】
また、有底の金属ケースの底面の厚みは２．０ｍｍのアルミニウムと、側壁部を構成する厚み１．０ｍｍのアルミニウムとからなり、底面に、ガス噴射口、熱電対、導通端子を所定の位置に取り付けた。また、底面から板状セラミックス体までの距離は２０ｍｍとした。
【０１２４】
その後、前記有底の金属ケースの開口部に、板状セラミックス体を重ね、その外周部にボルトを貫通させ、板状セラミックス体と有底の金属ケースが直接当たらないように、リング状の接触部材を介在させ、接触部材側より弾性体を介在させてナットを螺着することにより弾性的に固定することによりウェハ支持部材とした。
【０１２５】
尚、接触部材１７の断面は円形状で、リング状とした。円形状の断面の大きさは、直径１ｍｍとした。また、接触部材の材質はＳＵＳ３０４、炭素鋼を用いた。
【０１２６】
そして、載置面３の周辺部に直径５ｍｍの周辺凸部４を板状セラミックス体２に設けた凹部に埋設した。周辺凸部４の内接円の大きさは直径３０１ｍｍとした。また、純度９５％アルミナ、ムライト、イットリアを０．１〜５重量％添加した窒化アルミニウムで周辺凸部４を作製した。また、各周辺凸部４の外周を万能研削盤で加工し必要に応じ外周をダイヤモンド遊離砥粒で研磨しＲａが０．０５〜１０に調整した周辺凸部４を作製した。
【０１２７】
そして、周辺凸部４の熱伝導率の異なる各種のウェハ支持部材を試料Ｎｏ.２１〜２９とした。
【０１２８】
作製したウェハ支持部材の評価は、測温抵抗体が２９箇所に埋設された直径３００ｍｍの測温用ウェハを用いて行った。夫々のウェハ支持部材に電源を取り付け２５℃から２００℃まで５分間でウェハＷを昇温し、ウェハＷの温度を２００℃に設定してからウェハＷの平均温度が２００℃±０．５℃の範囲で一定となるまでの時間を応答時間として測定した。その１０分後のウェハ温度の最大値と最小値の差をウェハＷの温度差として測定した。その後、ウェハリフトピンを載置面の上面に突出させウェハＷを載置面から取り外し、不図示のハンドリングアームでウェハを取り外した。その後再びハンドリングアームからウェハＷをウェハリフトピンの上に載せ、ウェハリフトピンを降下させて、周辺凸部にガイドさせながら内側凸部の上端にウェハＷを載せた。そして、３分後に再びウェハリフトピンを上昇させて、ウェハＷを取り外した。このウェハＷ載置取り外しを１０００回繰り返し、その後ウェハＷの裏面の周辺部２０ｍｍ幅と側面に付着したパーティクルをＴＥＮＫＯＲ社製のパーティクルカウンタで評価した。
【０１２９】
それぞれの結果は表２に示す通りである。
【０１３０】
【表２】
Figure 0003929879
【０１３１】
表２の試料Ｎｏ．２１は、周辺凸部の熱伝導率が５Ｗ／（ｍ・Ｋ）と小さいことから、ウェハＷ面内の温度差が０．５１℃と大きく応答時間も６３秒と大きく好ましくなかった。
【０１３２】
また、試料Ｎｏ．２９は板状セラミックス体の熱伝導率が６０Ｗ／（ｍ・Ｋ）に対して周辺凸部の熱伝導率が１８０Ｗ／（ｍ・Ｋ）はその３倍と大きく、ウェハＷ面内の温度差は０．８℃と大きく好ましくなかった。
【０１３３】
これに対し、試料Ｎｏ．２２〜２７は周辺凸部の熱伝導率が２０Ｗ／（ｍ・Ｋ）以上と大きく、しかも板状セラミックス体の熱伝導率の２倍以下であることから、ウェハＷ面内の温度差は０．４５℃以下と小さく、応答時間も５５秒以下と小さく好ましいことが分った。
【０１３４】
更に、試料Ｎｏ．２２〜２６のように周辺凸部の外周面の表面粗さＲａが５以下であるとパーティクルの発生個数が２０００個以下と少なく更に好ましいことが分った。
【０１３５】
【発明の効果】
以上のように、本発明によれば、板状セラミックス体の一方の主面または内部に複数の抵抗発熱体を備え、他方の主面にウェハを載せる載置面を備えたウェハ支持部材であって、前記載置面の周辺部に３個以上の周辺部の凸部を設け、前記周辺凸部の内側に該凸部より高さの低い内側凸部を設けるとともに、上記内側凸部の上記載置面からの突出高さは０．０５〜０．５ｍｍであり、上記内側凸部は、上記載置面の中心から上記周辺凸部に内接する内接円の直径の０．５倍の範囲内に少なくとも１個、上記内接円の直径の０．５〜１倍の範囲内に少なくとも３個以上それぞれ同心円状に配置されていることにより、ウェハＷ面内の温度差を小さくできる。更に、過渡時のウェハＷ面の温度が安定するまでの応答時間を小さくできる。
【０１３６】
また、上記周辺部の凸部を構成する部材は載置面の凹部に取り付けることにより更にウェハＷ面内の温度を小さく、過渡時の応答時間を小さくできる。
【０１３７】
また、周辺凸部の熱伝導率を２０Ｗ／（ｍ・Ｋ）以上であり板状セラミックス体の熱伝導率の２倍以下とするとウェハＷ表面の温度差を小さく、温度応答時間が小さくなる。
【０１３８】
更に、周辺凸部の一部は板状セラミックス体の抵抗発熱体を囲む外接円の内部に設けると好ましい。
【図面の簡単な説明】
【図１】（ａ）は本発明のウェハ支持部材の一例を示す断面図、（ｂ）は同じく平面図である。
【図２】（ａ）〜（ｃ）は本発明のウェハ支持部材における周辺凸部の拡大断面図である。
【図３】（ａ）（ｂ）は本発明のウェハ支持部材における抵抗発熱体ゾーンの形状を示す概略平面図である。
【図４】本発明のウェハ支持部材における抵抗発熱体の形状を示す概略平面図である。
【図５】本発明のウェハ支持部材における抵抗発熱体の形状を示す概略平面図である。
【図６】本発明の他のウェハ支持部材の一例を示す断面図である。
【図７】従来のウェハ支持部材の一例を示す断面図である。
【図８】従来のウェハ支持部材の抵抗発熱体の形状を示す概略平面図である。
【符号の説明】
１、７１：ウェハ支持部材
２、７２：板状セラミックス体
３、７３：載置面
４：周辺凸部
５、７５：抵抗発熱体
６：給電部
７：均熱板
８：内側凸部
９：凹部
１０：ボルト
１１、７７：給電端子
１２：ガイド部材
１６：ボルト
１７：接触部材
１８：弾性体
１９、７９：金属ケース
２０：ナット
２１：底面
２３：孔
２４：ガス噴射口
２５：ウェハリフトピン
２６：貫通孔
２７：熱電対
２８：ガイド部材
Ｗ：半導体ウェハ[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a wafer heating apparatus mainly used for heating a wafer. For example, a thin film is formed on a wafer such as a semiconductor wafer, a liquid crystal device or a circuit board, or a resist solution applied on the wafer. The present invention relates to a wafer support member suitable for forming a resist film by dry baking.
[0002]
[Prior art]
A wafer support member for heating a semiconductor wafer (hereinafter abbreviated as a wafer) is used in a semiconductor thin film forming process, an etching process, a resist film baking process, and the like in a manufacturing process of a semiconductor manufacturing apparatus.
[0003]
The conventional semiconductor manufacturing apparatus has a batch type that heats a plurality of wafers at once and a sheet type that heats one wafer at a time. The single wafer type has excellent temperature controllability, so wiring of semiconductor elements is possible. Wafer support members have been widely used in accordance with demands for miniaturization of wafers and improved accuracy of wafer heat treatment temperature.
[0004]
As such a wafer support member, for example, Patent Document 1, Patent Document 2, and Patent Document 3 propose a wafer support member as shown in FIG.
[0005]
The wafer support member 71 is a plate-shaped ceramic. The The body 72 and the metal case 79 are main constituent elements, and a plate-like ceramic made of nitride ceramics or carbide ceramics in the opening of the bottomed metal case 79 made of metal such as aluminum. The The body 72 is fixed with a bolt 80 through a resin heat insulating connecting member 74, and the upper surface thereof is used as a mounting surface 73 on which the wafer W is placed, and a plate-like ceramic. The For example, a concentric resistance heating element 75 as shown in FIG. 8 was provided on the lower surface of the body 72.
[0006]
Furthermore, a power supply terminal 77 is brazed to the terminal portion of the resistance heating element 75, and the power supply terminal 77 is inserted into a lead wire drawing hole 76 formed in the bottom 79 a of the metal case 79. 78 was electrically connected.
[0007]
By the way, in such a wafer support member 71, it is important to make the temperature distribution of the wafer uniform in order to form a homogeneous film on the entire surface of the wafer W and to make the heating reaction state of the resist film uniform. It is. Therefore, in order to reduce the temperature difference in the surface of the wafer so far, a wafer support member 71 provided with wafer W support pins on the mounting surface 73 and floating the wafer W from the mounting surface 73 by a small distance is disclosed in Patent Document 4. It is described in.
[0008]
Patent Document 5 discloses a wafer support member in which a wall surrounding the wafer is provided on the periphery of the plate-like ceramic body 72, and a convex portion that comes into contact with the wall is provided to prevent a decrease in temperature around the wafer W.
[0009]
Further, in Patent Document 6, as shown in FIG. 9, a protrusion for fitting with the wafer W is formed on the outer edge of the plate-like ceramic body 72, and the wafer W conflicts with the inside of the protrusion. A wafer support member that realizes a uniform temperature distribution by forming a large number of convex bodies is disclosed.
[0010]
Further, Patent Document 7 discloses a wafer support member having a uniform temperature distribution on the wafer W by providing guide pins for positioning the wafer W around the plate-shaped ceramic body.
[0011]
Further, Patent Document 8 discloses a wafer support member that can adjust the temperature distribution of the wafer W by freely adjusting the height of the support pins of the wafer W. Also disclosed is a wafer support member in which guide pins are fitted to the support pins.
[0012]
However, both have the problem that a very complicated and delicate structure and control are required, and a wafer support member that can heat the temperature distribution more uniformly with a simple structure has been demanded.
[0013]
[Patent Document 1]
JP 2001-203156 A
[Patent Document 2]
JP 2001-313249 A
[Patent Document 3]
JP 2002-76102 A
[Patent Document 4]
JP-A-10-223642
[Patent Document 5]
JP-A-10-229114
[Patent Document 6]
JP 2002-237375 A
[Patent Document 7]
JP 2002-184683 A
[Patent Document 8]
JP 2001-68407 A
[0014]
[Problems to be solved by the invention]
In recent years, the size of wafers has been increased to improve production efficiency, but the semiconductor elements themselves have also diversified. Manufacturing with large-sized wafers does not necessarily lead to improvement in production efficiency. Therefore, an apparatus that can cope with the wafer size and heat treatment conditions is desired.
[0015]
Furthermore, in the chemically amplified resist that has begun to be used with the miniaturization of the wiring of the semiconductor element, not only the uniformity of the temperature of the wafer but also from the moment when the wafer is placed on the heat treatment apparatus until the heat treatment is finished. The transient temperature history is also extremely important, and it is desired that the wafer temperature be stabilized uniformly within about 60 seconds immediately after the wafer is placed.
[0016]
However, in the apparatuses introduced in Patent Document 5 and Patent Document 6, since the thickness of the peripheral portion of the plate-shaped ceramic body is large and the heat capacity is large, the transient temperature in the wafer W plane is not uniform, and the in-plane of the wafer The temperature difference is as large as 0.4 to 1.2 ° C., and there is a possibility that the response time until the temperature stabilizes becomes long due to the influence of heat radiation on the outer periphery of the plate-like ceramic body.
[0017]
Further, in the wafer support member described in Patent Document 8, there is a possibility that the temperature difference between the peripheral portion and the central portion of the wafer W cannot be adjusted, and it is difficult to finely adjust the height of the support pins, Even if it could be adjusted, the temperature difference on the wafer surface was as large as 1 ° C. or more.
[0018]
Furthermore, any wafer support member may have a longer time for uniformly heating the wafer W, rapidly raising the temperature of the wafer W, or rapidly lowering the temperature.
[0019]
[Means for Solving the Problems]
Main departure Ming the board A wafer supporting member having a plurality of resistance heating elements on one main surface or inside of a ceramic body and a mounting surface on which the wafer is placed on the other main surface, three on the periphery of the mounting surface Provide the above peripheral protrusions, and provide an inner protrusion with a low height inside the peripheral protrusions. In addition, the protruding height of the inner convex portion from the upper placement surface is 0.05 to 0.5 mm, and the inner convex portion is inscribed inscribed from the center of the upper placement surface to the peripheral convex portion. At least one in the range of 0.5 times the diameter of the circle and at least three in the range of 0.5 to 1 times the diameter of the inscribed circle are arranged concentrically. It is characterized by that.
[0020]
Moreover, the member which comprises the said peripheral convex part is the above It was attached to the recessed part formed in the mounting surface.
[0021]
The peripheral convex part is a circular ceramic. The The ceramic Of The thermal conductivity is 20 W / (m · K) or more and is smaller than twice the thermal conductivity of the plate-like ceramic body.
[0022]
Further, a part of the peripheral convex portion is inside a circumscribed circle surrounding the resistance heating element.
[0024]
Also, the resistance heating element the above The diameter D of the circumscribed circle is 90 to 99% of the diameter DP of the plate-like ceramic body.
[0025]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below.
[0026]
FIG. 1 (a) is a cross-sectional view showing an example of a wafer support member 1 according to the present invention. A plurality of plates are provided on one main surface or inside of a plate-like ceramic body 2 made of ceramics mainly composed of silicon carbide or aluminum nitride. And the other main surface is a mounting surface 3 on which the wafer W is placed, and a soaking plate 7 provided with a power feeding portion 6 electrically connected to the resistance heating member 5. A power supply terminal 11 is connected to the power supply unit 6. A metal case 19 surrounding these power feeding portions 6 is fixed to the peripheral portion of the other main surface of the plate-like ceramic body 2 via a connecting member 17.
[0027]
Further, the wafer lift pins 25 are plate-shaped ceramics. The The wafer W can be moved up and down through a hole penetrating the body 2 so that the wafer W can be placed on or lowered from the placement surface 3. Then, the power supply terminal 11 is connected to the power supply unit 6 and electric power is supplied from the outside, and the temperature W of the plate ceramic body 2 can be heated by the temperature measuring element 27 to heat the wafer W.
[0028]
When the resistance heating element 5 is divided into a plurality of zones, the temperature of each zone is controlled independently to supply power to the feeding terminals 11 of each feeding section 6, and the temperature of each temperature measuring element 27 is The electric power applied to the power supply terminal 11 is adjusted so as to be each set value so that the surface temperature of the wafer W placed on the placement surface 3 is uniform.
[0029]
The resistance heating element 5 is formed with a power feeding portion 6 made of a material such as gold, silver, palladium, platinum or the like, and the power feeding terminal 11 is brought into contact with the power feeding portion 6 to ensure conduction. As long as the power supply terminal 11 and the power supply unit 6 are a method that can ensure conduction, a method such as soldering or brazing may be used.
[0030]
In order to uniformly heat the surface of the disk-shaped wafer W corresponding to the mounting surface 3 of the wafer W, it is affected by the atmosphere around the wafer W, the wall surface facing the wafer W, and the flow of gas. This is because the surface temperature of the wafer W is designed to be symmetric with respect to the wafer W in order to prevent the surface temperature of the wafer W from varying. In order to uniformly heat the wafer W, the wafer support member 1 that matches the above-mentioned environment that is symmetric with respect to the wafer W is required. Further, the mounting surface 3 is divided symmetrically with respect to the resistance heating element zone. The It is preferable to form.
[0031]
As shown in FIG. 1B, the wafer support member 1 of the present invention is Condition Three or more peripheral convex portions 4 are provided in the peripheral portion of the mounting surface of the ceramic body 2, and an inner convex portion 8 having a lower height than the peripheral convex portion 4 is provided inside the peripheral convex portion. To do.
[0032]
The wafer W is transferred from an arm (not shown) and placed on the wafer lift pins 25 protruding on the mounting surface 3 of the plate-like ceramic body 2. The wafer lift pins 25 are lowered and the wafer W is placed on the inner convex portion 8 on the placement surface 3. In order to reduce the in-plane temperature difference of the wafer W, it is important to place the wafer W at an accurate position with respect to the plate-like ceramic body 2 in accordance with the center position of the plate-like ceramic body 2 provided with the resistance heating element 5. The peripheral protrusion 4 is used as a wafer guide, and the wafer W is preferably supported by the inner protrusion 8 while the periphery is in contact with the peripheral protrusion 4.
[0033]
In order for the peripheral convex portion 4 to prevent lateral deviation of the wafer W, at least three peripheral convex portions 4 are required on the same circumference, and the diameter of the inscribed circle in contact with the peripheral convex portion 4 is 1 than the diameter of the wafer W. It is preferable that the size is 0.001 to 1.01 times. By arranging in this way, the wafer W can be placed at an accurate position on the mounting surface 3, so that the heat from the plate-like ceramic body 2 provided with the resistance heating element 5 can be uniformly received. The surface temperature difference of W can be reduced.
[0034]
2A, 2B, and 2C are enlarged cross-sectional views showing the peripheral convex portion 4. FIG. FIG. 2A shows the peripheral convex portion 4 having a truncated cone shape. FIG. 2B shows the peripheral convex portion 4 having a shape in which a truncated cone is coupled on a cylinder. FIG.2 (c) shows the peripheral convex part 4 whose periphery consists of curved surfaces.
[0035]
The peripheral convex portion 4 is preferably provided on the same plane as the other main surface of the plate-like ceramic body 2, and the size of the inscribed circle surrounding the wafer W by the plurality of peripheral convex portions 4 is the tip. It is preferable that the portion is large and the bottom portion is small.
[0036]
In addition, like the wafer support members described in Patent Documents 5 and 6, the annular convex portion that prevents the lateral displacement of the wafer W is a plate-like ceramic body. 2 Therefore, there is a problem that the heat capacity of the peripheral portion of the plate-like ceramic body is increased, and the temperature difference in the wafer W surface during transition is large during the temperature increase. However, by providing an isolated peripheral convex portion in the peripheral portion of the plate-like ceramic body 2 of the present invention, an increase in the temperature difference in the wafer W plane at the time of transition can be prevented, and lateral deviation of the wafer W can be prevented.
[0037]
Further, in order to reduce the in-plane temperature difference of the wafer W, a concave portion 9 is formed on the mounting surface 3 of the plate-like ceramic body 2, a buried metal fitting is bonded to the concave portion 9, and the peripheral convex portion 4 is formed with a bolt 10. It is preferable to tighten and attach. By arranging in this way, the temperature distribution on the mounting surface 3 can be kept uniform, and the temperature difference in the wafer W surface can be reduced. The recessed ring 9 is an embedded ring made of a Fe-Ni-Co alloy having a thermal conductivity close to that of the plate-like ceramic body. so The peripheral convex part 4 can also be screwed.
[0038]
Further, the thermal conductivity of the peripheral convex portion 4 is preferably 20 W / (m · K) or more, and preferably has a thermal conductivity that is not more than twice the thermal conductivity of the plate-like ceramic body 2. When the thermal conductivity of the peripheral convex portion 4 is less than 20 W / (m · K), the temperature around the peripheral convex portion 4 is lowered. do it There is a possibility that the temperature difference in the wafer W surface becomes large. Further, when the thermal conductivity of the peripheral convex portion 4 exceeds twice the thermal conductivity of the plate-like ceramic body 2, the temperature of the peripheral convex portion 4 is likely to rise, and the wafer W surface in a transient state when the wafer W is heated. The internal temperature difference becomes large, which is not preferable. Preferably, if the thermal conductivity of the peripheral convex portion 4 is set to 30 W / (m · K) or higher and is equal to or lower than one time the thermal conductivity of the plate-like ceramic body 2, the temperature drop or rise around the peripheral convex portion 4 is reduced. Can be small.
[0039]
In order to reduce the surface temperature difference of the wafer W, it is preferable that a part of the peripheral protrusion 4 is inside a circumscribed circle surrounding the resistance heating element 5 of the plate-like ceramic body 2. Such an arrangement is preferable because the resistance heating element 5 can heat the mounting surface 3 in a range wider than the surface area of the wafer W, and the temperature difference in the surface of the wafer W is reduced.
[0040]
Moreover, it is preferable that the periphery convex part 4 is circular ceramics when planarly viewed, and it is more preferable that it is 5-30 mm in diameter. If the diameter is less than 5 mm, it can be fixed to the mounting surface 3 with high accuracy. When If the diameter exceeds 30 mm, the in-plane temperature difference of the wafer W may increase. The diameter is preferably 10 to 20 mm.
[0041]
Moreover, it is preferable that the surface roughness of the side surface of the peripheral convex part 4 is 0.1-5 micrometers in Ra. The side surface of the peripheral convex portion 4 is in contact with the end face of the wafer W or the edge portion of the end face. However, if Ra is 0.1 to 5 μm, the edge of the wafer W is lost or particles are generated even if it contacts with the wafer W. There is little fear. If Ra exceeds 5 μm or Rmax exceeds 10 μm, the edge of the wafer W may be lost or the surface of the peripheral protrusion 4 may be lost when the wafer W and the side surface of the peripheral protrusion 4 come into contact with each other, thereby generating particles.
[0042]
By guiding the periphery of the wafer W by the peripheral convex portion 4, the position of the wafer W in the mounting surface 3 can be accurately fixed.
[0043]
The distance between the mounting surface 3 and the wafer W supports the wafer W by the inner convex portion 8. In order to make the distance between the wafer W surface and the mounting surface 3 as uniform as possible, the inner convex portion 8 is placed. It is preferable that they are evenly arranged on the surface 3. The inner convex portion 8 is at least one in the range of 0.5 times the diameter of the inscribed circle inscribed from the center of the mounting surface 3 to the peripheral convex portion 4, and is 0.5 to 1 times the diameter of the inscribed circle. If at least three are arranged within the range, the deformation of the surface of the wafer W is small and can be supported uniformly, and deformation and warpage due to its own weight can be prevented. The temperature difference is preferably small.
[0044]
Further, the wafer W is spaced apart from the mounting surface 3 through the inner convex portion 8 at a constant interval, thereby preventing temperature variations in the wafer W surface due to one piece when directly contacting the mounting surface 3. it can. Then, by heating the wafer W via the gas on the mounting surface 3, the temperature in the wafer W surface can be raised uniformly, or the temperature in the wafer W surface can be kept uniform.
[0045]
The protrusion height from the mounting surface of the inner convex portion 8 that determines the distance between the wafer W and the mounting surface 3 is suitably 0.05 to 0.5 mm, and if it is less than 0.05 mm, the temperature of the mounting surface 3 is reduced. The temperature is rapidly transmitted to the wafer W, and the temperature difference in the wafer W surface is increased. On the other hand, if the thickness exceeds 0.5 mm, the transfer of heat transmitted from the mounting surface 3 to the wafer W is delayed, and the temperature difference in the wafer W surface is increased. More preferably, it is 0.07-0.2 mm.
[0046]
Further, the inner convex portion has at least one in the range of 0.5 times the diameter of the inscribed circle inscribed from the center of the mounting surface to the peripheral convex portion, and has a diameter of 0.5 to the inscribed circle. It is preferable to arrange at least three or more concentric circles within the range of 1 times because the temperature difference on the surface of the wafer W can be reduced by fixing the wafer W to the flat end. More preferably, if there are at least three in the range of 0.5 times the diameter of the inscribed circle and at least five in the range of 0.5 to 1 times the diameter of the inscribed circle, the deformation of the wafer W surface is reduced. Is further reduced, and the temperature difference in the surface of the wafer W can be reduced to 0.4 ° C. or less.
[0047]
FIG. 3A shows a wafer support member 1 of the present invention, which is a plate-like ceramic body. 2 A plurality of resistance heating element zones 4 are provided on one main surface, a circular resistance heating element zone 4a at the center, and a resistance heating element zone 4bc and a resistance heating element zone 4dg in two concentric rings outside. The example of arrangement | positioning of each resistance heating element zone 4 provided with these is shown.
[0048]
FIG. 3B shows a circular resistance heating element zone 4a in the center of the wafer support member 1 of the present invention and two fan-shaped resistance heating element zones 4b and 4c obtained by dividing the annular ring 4bc into two equal parts. Further, the wafer support member 1 is composed of four fan-shaped resistance heating element zones 4d, 4e, 4f, and 4g obtained by equally dividing the ring into four in the circumferential direction at positions facing each other in the outer ring 4dg. This is preferable because the surface temperature of the wafer W becomes more uniform.
[0049]
Each of the resistance heating element zones 4a to 4g of the wafer support member 1 can generate heat independently, and includes resistance heating elements 5a to 5g corresponding to the resistance heating element zones 4a to 4g.
[0050]
The annular resistance heating element zones 4bc and 4dg are divided into two and four in the radial direction, respectively, but this is not restrictive.
[0051]
Although the boundary line of the resistance heating element zones 4b and 4c in FIG. 3B is a straight line, it is not necessarily a straight line. Ah It may be. It is preferable that the resistance heating element zones 4 b and 4 c are centrosymmetric with respect to the center of the plate-like ceramic body 2.
[0052]
Similarly, the boundary lines of the resistance heating element zones 4d and 4e, 4e and 4f, 4f and 4g, 4g and 4d do not necessarily have to be straight lines, and each resistance heating element 4d to 4g has a plate shape. The center of the ceramic body 2 is preferably symmetric with respect to the center.
[0053]
Each of the resistance heating elements 5 is preferably manufactured by a printing method or the like, and is formed to have a width of 1 to 5 mm and a thickness of 5 to 50 μm. When the printing surface to be printed at a time becomes large, there is a possibility that the printing thickness may not be constant due to the difference in pressure between the squeegee and the screen on the left and right or front and back of the printing surface. In particular, when the size of the resistance heating element 5 is increased, the thickness of the resistance heating element 5 on the left and right sides is different and the designed heat generation may vary. The amount of heat generation varies, and the in-plane temperature difference between the wafer W increases, which is not preferable. In order to prevent the temperature variation caused by the variation in thickness of the resistance heating element, it has been found that it is effective to divide the individual resistance heating elements 5 having a large outer diameter, which is composed of one resistance heating element.
[0054]
Thus, the concentric annular resistance heating element zone excluding the central portion of the wafer W mounting surface 3 is divided into two parts on the left and right sides, and the larger annular resistance heating element zone is divided into four parts, thereby dividing the resistance heating element zone. To Since the printing size of a certain resistance heating element 5 can be reduced, the thickness of each part of the resistance heating element 5 can be made uniform, and a subtle temperature difference between the front, back, left and right of the wafer W can be corrected to correct the wafer W. The surface temperature can be made uniform.
[0055]
Further, as shown in FIG. 4, the diameter D of the circumscribed circle C of the resistance heating element 5 is preferably 90 to 99% of the diameter DP of the plate-like ceramic body 2. If the diameter D of the circumscribed circle C of the resistance heating element 5 is smaller than 90% of the diameter DP of the plate-like ceramic body 2, the time for rapidly increasing or decreasing the temperature of the wafer increases, and the temperature response characteristics of the wafer W are increased. Inferior.
[0056]
Further, in order to uniformly heat the surface temperature of the wafer W so as not to lower the temperature at the periphery of the wafer W, the diameter D is preferably about 1.02 to 1.1 times the diameter of the wafer W. The diameter DP of the plate-like ceramic body 2 is larger than the size of the plate-like ceramic body 2, and the size of the wafer W that can be uniformly heated is smaller than the diameter DP of the plate-like ceramic body 2. On the other hand, the heating efficiency for heating the wafer W is deteriorated. Furthermore, since the plate-like ceramic body 2 becomes large, the installation area of the wafer manufacturing apparatus becomes large, which is not preferable because the operating rate with respect to the installation area of the semiconductor manufacturing apparatus that needs to perform the maximum production with the minimum installation area is lowered.
[0057]
When the diameter D of the circumscribed circle C of the resistance heating element 5 is larger than 99% of the diameter DP of the plate-like ceramic body 2, the distance between the contact member 17 and the outer periphery of the resistance heating element 5 is small, and heat is generated from the outer periphery of the resistance heating element 5. Flows non-uniformly to the contact member 17, and in particular, heat flows from a portion where the arc-shaped pattern 51 in contact with the circumscribed circle C of the outer peripheral portion does not exist, and the arc-shaped pattern 51 of the outer peripheral portion is the central portion of the plate-like ceramic body 2. Since it bends, the temperature of the portion P where the arc-shaped pattern 51 is missing along the circumscribed circle C surrounding the resistance heating element 5 may be lowered, and the in-plane temperature difference of the wafer W may be increased. More preferably, the diameter D of the circumscribed circle C of the resistance heating element 5 is 92 to 97% of the diameter DP of the plate-like ceramic body 2.
[0058]
Further, as shown in FIG. 1A, when the plate-shaped ceramic body 2 and the metal case 19 have substantially the same external shape and the metal case 19 supports the plate-shaped ceramic body 2 from below, the temperature difference in the plane of the wafer W is increased. In order to make it smaller, the diameter D of the circumscribed circle C of the resistance heating element 5 is 92 to 95%, more preferably 93 to 95% of the diameter DP of the plate-like ceramic body 2.
[0059]
On the other hand, when the metal case is connected so as to cover the outer peripheral surface of the plate-like ceramic body 2 as shown in FIG. 6, the diameter D of the circumscribed circle C of the resistance heating element 5 is equal to the diameter DP of the plate-like ceramic body 2. 95-98% is preferable, More preferably, it is 96-97%.
[0060]
One main surface side of a plate-like ceramic body 2 having a plate thickness of 1 to 7 mm is used as a mounting surface 3 on which a wafer is placed, and a wafer support member provided with a resistance heating element 5 on the lower surface of the plate-like ceramic body 2 1, the thickness of the resistance heating element 5 is 5 to 50 μm, and the ratio of the area of the resistance heating element 5 in the circumscribed circle C to the area of the circumscribed circle C surrounding the resistance heating element 5 is 5 to 50. % Is preferred.
[0061]
That is, if the ratio of the area of the resistance heating element 5 in the circumscribed circle C to the area of the circumscribed circle C surrounding the resistance heating element 5 is less than 5%, Since the facing interval S1 of the region becomes too large, the surface temperature of the mounting surface 3 corresponding to the interval S1 without the resistance heating element 5 becomes smaller than other portions, and the temperature of the mounting surface 3 is made uniform. On the contrary, if the ratio of the area of the resistance heating element 5 in the circumscribed circle C to the area of the circumscribed circle C surrounding the resistance heating element 5 exceeds 50%, the plate ceramic The The thermal expansion difference between the body 2 and the resistance heating element 5 is 3.0 × 10 -6 Even if it is approximated to below / ° C, the thermal stress acting between the two is too large, so the plate-like ceramic The Body 2 is hard to deform ceramic The Although it is made of a sintered body, its plate thickness t is as thin as 1 mm to 7 mm, so that when the resistance heating element 5 is heated, a plate-like ceramic is formed so that the mounting surface 3 side becomes concave. The This is because the body 2 is warped, and as a result, the temperature of the central portion of the wafer W becomes lower than the peripheral edge, and the temperature variation may increase.
[0062]
Preferably, the ratio of the area of the resistance heating element 5 in the circumscribed circle C to the area of the circumscribed circle C surrounding the resistance heating element 5 is 10% to 30%, more preferably 15% to 25%. Is preferred.
[0063]
Furthermore, in order to efficiently exhibit such an effect, the thickness of the resistance heating element 5 is preferably set to 5 to 50 μm.
[0064]
This is because if the thickness of the resistance heating element 5 is less than 5 μm, it becomes difficult to uniformly print the resistance heating element 5 by screen printing, and the thickness of the resistance heating element 5 exceeds 50 μm. Even if the ratio of the area occupied by the resistance heating element 5 to the circumscribed circle P1 is 50% or less, the thickness of the resistance heating element 5 is large, and the rigidity of the resistance heating element 5 is increased. The body 2 The plate-like ceramic is affected by the expansion and contraction of the resistance heating element 5 due to the temperature change of The The body 2 may be deformed. Further, it is difficult to print with a uniform thickness by screen printing, and the temperature difference on the surface of the wafer W may increase. A preferable thickness of the resistance heating element 5 is 10 to 30 μm.
[0065]
As a pattern shape of the resistance heating element 5 of the present invention, a folded pattern as shown in FIG. 3 or a plurality of blocks as shown in FIG. 4 and FIG. Since the wafer support member 1 of the present invention is important to uniformly heat the wafer W, these pattern shapes have a strip-like resistance heat generation. It is preferable that the density of each part of the body 5 is uniform. As shown in FIG. 4, the resistance heating elements 5d, 5e, 5d, and 5f located on the outer peripheral portion of the plate-like ceramic body 2 are arc-shaped patterns 51 that are concentric in the portion far from the center of the plate-like ceramic body 2. It is preferable that it consists of the connection pattern 52 connected continuously. However, as shown in FIG. The body 7 In the resistance heating element pattern in which the densely spaced portions and the rough portions of the resistance heating elements 25 appear alternately from the center of 2 in the radial direction, the surface temperature of the wafer W corresponding to the rough portions is small and dense. This is not preferable because the temperature of the wafer W corresponding to the portion is increased and the entire surface of the wafer W cannot be heated uniformly.
[0066]
Further, when the resistance heating element 5 is divided into a plurality of blocks, it is preferable to uniformly heat the wafer W on the mounting surface 3 by independently controlling the temperature of each block.
[0067]
The resistance heating element 5 is a plate-like ceramic formed by printing an electrode paste containing glass frit or metal oxide on conductive metal particles. The It is printed and baked on the body 2, and it is preferable to use at least one metal of Au, Ag, Cu, Pd, Pt, and Rh as the metal particles, and the glass frit includes B, Si, and Zn. Plate ceramic made of oxide The 4.5 × 10 smaller than the thermal expansion coefficient of the body 2 -6 It is preferable to use low-expansion glass at / ° C. or lower, and it is preferable to use at least one selected from silicon oxide, boron oxide, alumina, and titania as the metal oxide.
[0068]
Here, the reason why at least one kind of metal of Au, Ag, Cu, Pd, Pt, Rh is used as the metal particles forming the resistance heating element 5 is that the electric resistance is small.
[0069]
The glass frit forming the resistance heating element 5 is made of an oxide containing B, Si and Zn, and the thermal expansion coefficient of the metal particles constituting the resistance heating element 5 is a plate-like ceramic. The Since the thermal expansion coefficient of the body 2 is larger, the thermal expansion coefficient of the resistance heating element 5 The To get close to the coefficient of thermal expansion of the body 2 The 4.5 × 10 smaller than the thermal expansion coefficient of the body 2 -6 This is because it is preferable to use a low expansion glass having a temperature of / ° C. or lower.
[0070]
Further, as the metal oxide forming the resistance heating element 5, using at least one selected from silicon oxide, boron oxide, alumina, and titania has excellent adhesion to the metal particles in the resistance heating element 5, Moreover, the thermal expansion coefficient is plate-like ceramic The This is because the thermal expansion coefficient is close to that of the body 2 and the adhesiveness with the plate-like ceramic body 2 is also excellent.
[0071]
However, if the content of the metal oxide exceeds 80% with respect to the resistance heating element 5, the plate-like ceramic The Although the adhesion with the body 2 is increased, the resistance value of the resistance heating element 5 is increased, which is not preferable. Therefore, the content of the metal oxide is preferably 60% or less.
[0072]
The resistance heating element 5 made of conductive metal particles and glass frit or metal oxide has a thermal expansion difference of 3.0 × 10 5 from the plate-like ceramic body 2. -6 It is preferable to use one that is / ° C or lower.
[0073]
That is, the resistance heating element 5 and the plate-like ceramic The The thermal expansion difference with the body 2 is 0.1 × 10 -6 / ° C is difficult to manufacture, and conversely, the resistance heating element 5 and plate ceramic The The thermal expansion difference with the body 2 is 3.0 × 10 -6 / ° C, when the resistance heating element 5 is heated, a plate-like ceramic The The mounting surface 3 side warps in a concave shape due to the thermal stress acting between the body 2 and the body 2. fear Because there is.
[0074]
Further, regarding a method of feeding power to the resistance heating element 5, the power feeding terminal 11 installed on the bottomed metal case 19 is pressed against the power feeding portion 6 formed on the surface of the plate-like ceramic body 2 by a spring (not shown). Secure the connection and supply power. This is because if the terminal portion made of metal is embedded in the plate-like ceramic body 2 having a thickness of 2 to 5 mm, the thermal uniformity is deteriorated due to the heat capacity of the terminal portion. Therefore, as in the present invention, the thermal stress due to the temperature difference between the plate-shaped ceramic body 2 and the bottomed metal case 19 is reduced by pressing the power supply terminal 11 with a spring to ensure electrical connection. The electrical conduction can be maintained with high reliability. Further, an elastic conductor may be inserted as an intermediate layer in order to prevent the contact from becoming a point contact. This intermediate layer is effective by simply inserting a foil-like sheet. And it is preferable that the diameter by the side of the electric power feeding part 6 of the electric power feeding terminal 11 shall be 1.5-5 mm.
[0075]
Further, the temperature of the plate-like ceramic body 2 is measured by a thermocouple 27 whose tip is embedded in the plate-like ceramic body 2. As the thermocouple 27, it is preferable to use a sheath-type thermocouple 27 having an outer diameter of 0.8 mm or less from the viewpoint of responsiveness and workability of holding. In order to improve the reliability of temperature measurement, it is preferable that the tip of the thermocouple 27 has a hole formed in the plate-shaped ceramic body 2 and is fixed to the inner wall surface of the hole by a fixing member installed therein. . Similarly, it is also possible to perform temperature measurement by embedding a temperature measuring resistor such as a thermocouple of a wire or Pt.
[0076]
In FIG. 1 (a), a plate-like ceramic is used. The Although the wafer supporting member 1 having only the resistance heating element 5 on the other main surface 3 of the body 2 is shown, the present invention is for electrostatic adsorption or plasma generation between the main surface 3 and the resistance heating element 5. Needless to say, the electrode may be embedded.
[0077]
A more detailed configuration will be described.
[0078]
FIG. 1A is a cross-sectional view showing an example of a wafer support member according to the present invention, a plate-like ceramic having a plate thickness t of 1 to 7 mm and a Young's modulus of 100 to 200 ° C. of 200 to 450 MPa. The One main surface of the body 2 is used as a mounting surface 3 on which the wafer W is placed, a resistance heating element 5 is formed on the other main surface, and a power feeding unit 6 electrically connected to the resistance heating element 5 is provided. It is a thing.
[0079]
A plate-like ceramic having a Young's modulus of 100 to 200 ° C. of 200 to 450 MPa The As the material of the body 2, alumina, silicon nitride, sialon, and aluminum nitride can be used. Among them, aluminum nitride has a high heat of 50 W / (m · K) or more, more preferably 100 W / (m · K) or more. A plate-like ceramic with conductivity and excellent corrosion resistance and plasma resistance against corrosive gases such as fluorine and chlorine. The It is suitable as a material for the body 2.
[0080]
The thickness of the plate-like ceramic body 2 is more preferably 2 to 5 mm. When the thickness of the plate-like ceramic body 2 is less than 2 mm, the strength of the plate-like ceramic body 2 is lost, and when the cooling heat from the gas injection port 24 is blown when heating by the heat generation of the resistance heating body 5, This is because the plate-shaped ceramic body 2 may not be able to withstand stress and may crack. On the other hand, if the thickness of the plate-like ceramic body 2 exceeds 5 mm, the heat capacity of the plate-like ceramic body 2 increases, so that there is a possibility that the time until the temperature at the time of heating and cooling becomes stable becomes longer.
[0081]
The plate-like ceramic body 2 has a ring-shaped contact member 17 so that the bolt 16 passes through the outer periphery of the opening of the bottomed metal case 19 and the plate-like ceramic body 2 and the bottomed metal case 19 do not directly contact each other. The elastic body 18 is interposed from the bottomed metal case 19 side, and the nut 20 is screwed to be elastically fixed. Thereby, even if the bottomed metal case 19 is deformed when the temperature of the plate-like ceramic body 2 fluctuates, the elastic body 18 absorbs this, thereby suppressing the warp of the plate-like ceramic body 2, It is possible to prevent temperature variations due to warpage of the plate-shaped ceramic body 2 from occurring on the wafer surface.
[0082]
The cross-section of the ring-shaped contact member 17 may be either polygonal or circular. However, when the plate-shaped ceramic body 2 and the contact member 17 are in contact with each other in a plane, the contact portion of the plate-shaped ceramic body 2 and the contact member 17 is in contact. If the width is 0.1 mm to 13 mm, the heat of the plate-like ceramic body 2 flows to the bottomed metal case 19 via the contact member 17. Ru Reduce the amount Toga it can. And the temperature difference in the surface of the wafer W is small, and the wafer W can be heated uniformly. . Good It is preferably 0.1 to 8 mm. If the width of the contact portion of the contact member 17 is 0.1 mm or less, the contact portion may be deformed when the contact is fixed to the plate-like ceramic body 2, and the contact member may be damaged. Further, when the width of the contact portion of the contact member 17 exceeds 13 mm, the heat of the plate-like ceramic body 2 flows to the contact member, the temperature of the peripheral portion of the plate-like ceramic body 2 is lowered, and the wafer W is heated uniformly. It becomes difficult to do. Preferably, the width of the contact portion between the contact member 17 and the plate-like ceramic body 2 is 0.1 mm to 8 mm, more preferably 0.1 to 2 mm.
[0083]
Further, the thermal conductivity of the contact member 17 is preferably smaller than the thermal conductivity of the plate-like ceramic body 2. If the thermal conductivity of the contact member 17 is smaller than the thermal conductivity of the plate-like ceramic body 2, the temperature distribution in the wafer W surface placed on the plate-like ceramic body 2 can be heated uniformly, and the plate-like ceramic body 2. When the temperature is raised or lowered, the amount of heat transferred to the contact member 17 is small, and there is little thermal interference with the bottomed metal case 19, so that it is easy to change the temperature quickly.
[0084]
In the wafer support member 1 in which the thermal conductivity of the contact member 17 is smaller than 10% of the thermal conductivity of the plate-like ceramic body 2, it is difficult for the heat of the plate-like ceramic body 2 to flow into the bottomed metal case 19. , Atmosphere The amount of heat flowing due to heat transfer by ambient gas (here, air) or radiant heat increases, and the effect is small.
[0085]
When the thermal conductivity of the contact member 17 is higher than the thermal conductivity of the plate-like ceramic body 2, the heat around the plate-like ceramic body 2 flows to the bottomed metal case 19 via the contact member 17 and is present. While heating the bottom metal case 19, the temperature of the peripheral part of the plate-shaped ceramic body 2 falls, and the temperature difference in the wafer W surface becomes large, which is not preferable. In addition, since the bottomed metal case 19 is heated, even if it is attempted to cool the plate-like ceramic body 2 by injecting air from the gas injection port 24, the cooling time is large because the temperature of the bottomed metal case 19 is high. Or when it is heated to a certain temperature, there is a possibility that the time until the temperature reaches a certain temperature is increased.
[0086]
On the other hand, as a material constituting the contact member 17, the Young's modulus of the contact member is preferably 1 GPa or more, and more preferably 10 GPa or more in order to hold a small contact portion. By setting such a Young's modulus, the width of the contact portion is as small as 0.1 mm to 8 mm, and the plate-like ceramic body 2 is fixed to the bottomed metal case 19 with the bolt 16 via the contact member 17, The contact member 17 is not deformed, and the plate-shaped ceramic body 2 can be held with high accuracy without being displaced or changing in parallelism.
In addition, the precision which cannot be obtained with the contact member which consists of resin which added fluororesin and glass fiber like Unexamined-Japanese-Patent No. 2001-313249 can be achieved.
[0087]
As the material of the contact member 17, metals such as carbon steel made of iron and carbon and special steel added with nickel, manganese, and chromium are preferable because of their large Young's modulus. Further, as the material having a low thermal conductivity, so-called kovar of stainless steel or Fe—Ni—Co alloy is preferable, and the material of the contact member 17 is selected so as to be smaller than the thermal conductivity of the plate-like ceramic body 2. Is preferred.
[0088]
Furthermore, since the contact portion between the contact member 17 and the plate-like ceramic body 2 is small, and even if the contact portion is small, the contact portion is not liable to be lost and particles can be generated. The cross section of the contact member 17 cut at a plane perpendicular to the body 2 is preferably circular rather than polygonal. When a circular wire having a cross section diameter of 1 mm or less is used as the contact member 17, the plate-like ceramic body 2 and the bottomed metal case 19 are used. It is possible to raise and lower the temperature of the wafer W evenly and quickly without changing the position of the wafer W.
[0089]
The relationship between the configuration of the contact member 17 and the arrangement of the plate-like ceramic body 2 and the resistance heating element 5 has been described above. The arrangement is such that a part of the peripheral convex portion 4 surrounds the resistance heating element 5. Since it exists inside D, it is needless to say that the influence of the peripheral protrusion 4 on the in-plane temperature of the wafer W is taken into consideration.
[0090]
Next, the bottomed metal case 19 has a side wall portion 22 and a bottom surface 21, and the plate-like ceramic body 2 is installed so as to cover the opening of the bottomed metal case 19. Further, the bottomed metal case 19 is provided with a hole 23 for discharging a cooling gas, and a power supply terminal for conducting to a power supply portion 6 for supplying power to the resistance heating element 5 of the plate-like ceramic body 2. 11. A gas injection port 24 for cooling the plate-like ceramic body 2 and a thermocouple 27 for measuring the temperature of the plate-like ceramic body 2 are provided.
[0091]
The depth of the bottomed metal case 19 is 10 to 50 mm, and the bottom surface 21 is preferably installed at a distance of 10 to 50 mm from the plate-like ceramic body 2. More preferably, it is 20-30 mm. This is because heat equalization of the mounting surface 3 is facilitated by radiant heat between the plate-like ceramic body 2 and the bottomed metal case 19, and at the same time, there is a heat insulation effect from the outside, so the temperature of the mounting surface 3 is constant. This is because the time until the temperature becomes uniform is shortened.
[0092]
Then, work such as placing the wafer W on the placement surface 3 or lifting it from the placement surface 3 is performed by lift pins 25 installed in the bottomed metal case 19 so as to be movable up and down. The wafer W is held in a state of being lifted from the mounting surface 3 by the wafer support pins 8 so as to prevent temperature variation due to contact with each other.
[0093]
Further, in order to heat the wafer W by the wafer heating apparatus 1, the lift pin 25 is lowered after the wafer W carried to the upper side of the mounting surface 3 by the transfer arm (not shown) is supported by the lift pin 25. The wafer W is then placed on the placement surface 3.
[0094]
Next, when the wafer support member 1 is used for forming a resist film, if the main component of the plate-like ceramic body 2 is silicon carbide, it does not react with moisture in the atmosphere and does not generate gas. Even when the resist film is applied to the wafer W, fine wirings can be formed at a high density without adversely affecting the structure of the resist film. At this time, it is necessary that the sintering aid does not contain nitrides that may react with water to form ammonia or amines.
[0095]
In the silicon carbide sintered body forming the plate-like ceramic body 2, boron (B) and carbon (C) are added as sintering aids to the main component silicon carbide, or alumina (Al 2 O Three ) Yttria (Y 2 O Three It is obtained by adding a metal oxide such as), mixing well, processing into a flat plate, and firing at 1900-2100 ° C. Silicon carbide may be either mainly α-type or β-type.
[0096]
On the other hand, when the silicon carbide sintered body is used as the plate-like ceramic body 2, glass or resin is used as an insulating layer for maintaining insulation between the plate-like ceramic body 2 having semiconductivity and the resistance heating element 5. When glass is used, if the thickness is less than 100 μm, the withstand voltage is less than 1.5 kV and the insulation cannot be maintained. Conversely, if the thickness exceeds 400 μm, the plate-like ceramic body 2 is formed. Since the thermal expansion difference between the silicon carbide sintered body and the aluminum nitride sintered body becomes too large, cracks are generated and the insulating layer does not function. Therefore, when glass is used as the insulating layer, the thickness of the insulating layer 4 is preferably formed in the range of 100 to 400 μm, and desirably in the range of 200 μm to 350 μm.
[0097]
Furthermore, the main surface opposite to the mounting surface 3 of the plate-shaped ceramic body 2 has a flatness of 20 μm or less and a surface roughness of the center line average roughness from the viewpoint of improving the adhesion with the insulating layer 4 made of glass or resin. The thickness (Ra) is preferably polished to 0.1 μm to 0.5 μm.
[0098]
Further, when the plate-like ceramic body 2 is formed of a sintered body mainly composed of aluminum nitride, Y is used as a sintering aid for the main component aluminum nitride. 2 O Three And Yb 2 O Three It is obtained by adding a rare earth element oxide such as CaO and an alkaline earth metal oxide such as CaO as necessary and mixing them well, processing into a flat plate shape, and then firing at 1900 to 2100 ° C. in nitrogen gas. In order to improve the adhesion of the resistance heating element 5 to the plate-like ceramic body 2, an insulating layer made of glass may be formed. However, when sufficient glass is added in the resistance heating element 5 and sufficient adhesion strength can be obtained by this, it can be omitted.
[0099]
The glass forming this insulating layer may be crystalline or amorphous, and has a heat-resistant temperature of 200 ° C. or higher and a thermal expansion coefficient in the temperature range of 0 ° C. to 200 ° C. -5 x 10 for the thermal expansion coefficient of the ceramics -7 / ° C to + 5 × 10 -7 It is preferable to select and use one in the range of / ° C. That is, if a glass whose thermal expansion coefficient is out of the above range is used, the difference in thermal expansion from the ceramic forming the plate-like ceramic body 2 becomes too large, so that defects such as cracks and delamination occur during cooling after baking the glass. It is because it is easy to occur.
[0100]
In addition, as a means for depositing an insulating layer made of glass on the plate-like ceramic body 2, an appropriate amount of the glass paste is dropped on the center of the plate-like ceramic body 2, and is spread and applied uniformly by a spin coating method. Alternatively, the glass paste may be baked at a temperature of 600 ° C. or higher after being uniformly applied by a screen printing method, a dipping method, a spray coating method, or the like. When glass is used as the insulating layer, the surface of the plate-like ceramic body 2 made of a silicon carbide sintered body or an aluminum nitride sintered body is heated to a temperature of about 850 to 1300 ° C. to deposit the insulating layer. By subjecting to an oxidation treatment, adhesion to an insulating layer made of glass can be enhanced.
[0101]
【Example】
(Example 1)
First, 1.0% by mass of yttrium oxide in terms of weight was added to the aluminum nitride powder, and further kneaded for 48 hours with a ball mill using isopropyl alcohol and urethane balls to produce an aluminum nitride slurry.
[0102]
Next, the aluminum nitride slurry was passed through 200 mesh to remove urethane balls and ball mill wall debris, and then dried at 120 ° C. for 24 hours in an explosion-proof dryer.
[0103]
Next, the obtained aluminum nitride powder was mixed with an acrylic binder and a solvent to produce an aluminum nitride slip, and a plurality of aluminum nitride green sheets were produced by a doctor blade method.
[0104]
And the resulting aluminum nitride C A laminate was formed by thermocompression bonding of a plurality of green sheets.
[0105]
Thereafter, the laminate is degreased at a temperature of 500 ° C. for 5 hours in a non-oxidizing gas stream, and then fired at a temperature of 1900 ° C. for 5 hours in a non-oxidizing atmosphere to obtain various thermal conductivities. A plate-like ceramic body having the same was produced.
[0106]
Then, the aluminum nitride sintered body is subjected to grinding, and a plate-like ceramic having a disc shape with a plate thickness of 3 mm and a diameter of 330 mm. Body and A plate-like ceramic body having a plate thickness of 4 mm, an annular convex portion at the periphery, and a center portion having a diameter of 301 mm and a plate thickness of 3 mm was produced. Further, three through holes were formed uniformly on a concentric circle 60 mm from the center. The through-hole diameter was 4 mm.
[0107]
Next, plate ceramics the body's In order to deposit the resistance heating element 5 on top, a conductive paste prepared by kneading Au powder and Pd powder as conductive materials and a glass paste added with a binder having the same composition as described above is obtained by screen printing. After printing to the pattern shape, the organic solvent is dried by heating to 150 ° C., and after further degreasing treatment at 550 ° C. for 30 minutes, baking is performed at a temperature of 700 to 900 ° C., so that the thickness is 50 μm. A resistance heating element 5 was formed.
[0108]
Resistance heating element N The arrangement is such that a resistance heating element zone is formed in one circular shape at the center, the outer ring is divided into two equal resistance heating element zones, and the outer ring is divided into four resistance heating element zones. A total of seven resistance heating element zones divided into two were formed.
[0109]
The bottom of the bottomed metal case is made of 2.0mm of aluminum and 1.0mm of aluminum constituting the side wall, and the gas injection port, thermocouple, and conduction terminal are attached to the bottom of the case. It was. The distance from the bottom surface to the plate-like ceramic body was 20 mm.
[0110]
After that, a plate-shaped ceramic body is overlaid on the opening of the bottomed metal case, and a bolt is passed through the outer periphery thereof, so that the plate-shaped ceramic body and the bottomed metal case do not directly contact each other. Screw the nut with the elastic member from the contact member side. do it A wafer support member was obtained by elastically fixing.
[0111]
The contact member 17 has a circular cross section and a ring shape. The size of the circular cross section was 1 mm in diameter. The material of the contact member was SUS304 or carbon steel.
[0112]
Thereafter, one inner convex part at the center of the mounting surface and three inner convex parts at a distance of 85 mm from the center, and five inner convex parts at a distance of 130 mm from the center were attached to Sample No. 1 and 2.
[0113]
Sample No. 1 is a peripheral projection on the periphery of the plate-like ceramic body 2 Part Attached at three equal locations. Sample No. Reference numeral 2 denotes a conventional wafer support member in which the peripheral portion of the plate-like ceramic body is formed to protrude 1 mm from the mounting surface.
[0114]
Evaluation of the produced wafer support member was performed using a temperature measuring wafer having a diameter of 300 mm in which temperature measuring resistors were embedded in 29 locations. A power supply is attached to each wafer support member, the wafer W is heated from 25 ° C. to 200 ° C. in 5 minutes, the temperature of the wafer W is set to 200 ° C., and then the average temperature of the wafer W is 200 ° C. ± 0.5 ° C. The time until it became constant within the range was maintained. Then, the wafer lift pins are raised, the wafer W is removed, the wafer W is cooled to room temperature, and then placed on the wafer support member again, and the time until the average temperature of the wafer W reaches 200 ° C. ± 0.5 ° C. is measured as the response time. did. Thereafter, the temperature difference in the wafer W plane at the time when the wafer W average temperature was maintained at 200 ° C. for 30 minutes was measured.
[0115]
Each result is as shown in Table 1.
[0116]
[Table 1]
Figure 0003929879
[0117]
The wafer supporting member 1 according to the present invention having the peripheral convex portion 4 isolated around the mounting surface and having the inner convex portion 4 has a small temperature difference in the wafer W plane of 0.35 ° C. and a response time of 35. It was found that it showed excellent characteristics as small as 2 seconds.
[0118]
On the other hand, Sample No. 2 having an annular convex portion on the periphery of the mounting surface has a small temperature difference within the wafer W surface of 0.41 ° C., but the response time is as large as 63 seconds and uniform. A resist film could not be produced.
[0119]
Sample No. 3 having no inner convex portion had a large temperature difference in the wafer W plane of 0.63 ° C. and a response time of 47 seconds.
[0120]
(Example 2)
A plate-like ceramic body was produced in the same manner as in Example 1.
[0121]
Then, the aluminum nitride sintered body is ground to produce a plurality of disk-shaped ceramic bodies 2 having a disk thickness of 3 mm and a diameter of 330 mm, and three through-holes are equally formed on a concentric circle 60 mm from the center. Formed. The through-hole diameter was 4 mm.
[0122]
Next, in order to deposit the resistance heating element 5 on the plate-like ceramic body 2, a conductor paste produced by kneading a glass paste to which Au powder, Pd powder and a binder having the same composition as described above are added as a conductive material. Is printed in a predetermined pattern shape by a screen printing method, heated to 150 ° C. to dry the organic solvent, further degreased at 550 ° C. for 30 minutes, and then baked at a temperature of 700 to 900 ° C. Thus, the resistance heating element 5 having a thickness of 50 μm was formed. The pattern of the resistance heating element 5 is divided into a circle and an annular shape radially from the central portion, a pattern is formed in one circular shape in the central portion, and a pattern is formed in two in the outer annular portion. Furthermore, a total of 7 patterns of 4 patterns on the outermost periphery were formed. Then, the diameter of the circumscribed circle C of the outermost four patterns was set to 310 mm, and the diameter of the plate ceramic was changed. After that, the plate-like ceramic body 2 was manufactured by brazing and fixing the feeding portion 6 to the resistance heating element 5.
[0123]
Further, the bottom of the bottomed metal case is made of 2.0 mm aluminum and 1.0 mm thick aluminum constituting the side wall, and the gas injection port, the thermocouple, and the conduction terminal are arranged at predetermined positions on the bottom. Attached to. The distance from the bottom surface to the plate-like ceramic body was 20 mm.
[0124]
After that, a plate-shaped ceramic body is overlaid on the opening of the bottomed metal case, and a bolt is passed through the outer periphery thereof, so that the plate-shaped ceramic body and the bottomed metal case do not directly contact each other. A wafer support member was obtained by interposing a member and elastically fixing the member by screwing a nut through an elastic body from the contact member side.
[0125]
The contact member 17 has a circular cross section and a ring shape. The size of the circular cross section was 1 mm in diameter. The material of the contact member was SUS304 or carbon steel.
[0126]
Then, a peripheral convex portion 4 having a diameter of 5 mm was embedded in a concave portion provided in the plate-like ceramic body 2 in the peripheral portion of the mounting surface 3. The size of the inscribed circle of the peripheral convex portion 4 was 301 mm in diameter. Moreover, the peripheral convex part 4 was produced with the aluminum nitride which added 0.1-5 weight% of 95% purity alumina, mullite, and yttria. Moreover, the periphery convex part 4 which processed the outer periphery of each peripheral convex part 4 with the universal grinder, and grind | polished the outer periphery with the diamond loose abrasive as needed, and produced Ra adjusted to 0.05-10 was produced.
[0127]
And the various wafer support members in which the thermal conductivity of the peripheral convex part 4 differs were made into sample Nos. 21-29.
[0128]
Evaluation of the produced wafer support member was performed using a temperature measuring wafer having a diameter of 300 mm in which temperature measuring resistors were embedded in 29 locations. A power supply is attached to each wafer support member, the wafer W is heated from 25 ° C. to 200 ° C. in 5 minutes, the temperature of the wafer W is set to 200 ° C., and then the average temperature of the wafer W is 200 ° C. ± 0.5 ° C. The time until it became constant in the range of was measured as the response time. The difference between the maximum value and the minimum value of the wafer temperature after 10 minutes was measured as the temperature difference of the wafer W. Thereafter, the wafer lift pins protruded from the upper surface of the mounting surface to remove the wafer W from the mounting surface, and the wafer was removed by a handling arm (not shown). After that, the wafer W is again placed on the wafer lift pins from the handling arm, the wafer lift pins are lowered, and the inner convex portion is guided while being guided to the peripheral convex portion. of A wafer W was placed on the upper end. Then, after 3 minutes, the wafer lift pins were raised again and the wafer W was removed. This wafer W mounting / removal was repeated 1000 times, and then the particles attached to the peripheral portion 20 mm width and the side surface of the back surface of the wafer W were evaluated with a particle counter manufactured by TENKOR.
[0129]
Each result is as shown in Table 2.
[0130]
[Table 2]
Figure 0003929879
[0131]
Sample No. in Table 2 No. 21 has a small thermal conductivity of 5 W / (m · K) at the peripheral convex portion, and therefore the temperature difference in the wafer W surface was as large as 0.51 ° C. and the response time was as large as 63 seconds, which was not preferable.
[0132]
Sample No. 29, the thermal conductivity of the plate-shaped ceramic body is 60 W / (m · K), and the thermal conductivity of the peripheral convex portion is 180 W / (m · K), which is three times as large. Was not as large as 0.8 ° C.
[0133]
In contrast, sample no. In Nos. 22 to 27, the thermal conductivity of the peripheral convex portion is as large as 20 W / (m · K) or more, and is not more than twice the thermal conductivity of the plate-like ceramic body. It was found to be as small as .45 ° C. or less and a response time as small as 55 seconds or less.
[0134]
Furthermore, sample no. It has been found that when the surface roughness Ra of the outer peripheral surface of the peripheral convex portion is 5 or less as in 22 to 26, the number of particles generated is as small as 2000 or less, which is more preferable.
[0135]
【The invention's effect】
As described above, according to the present invention, there is provided a wafer support member including a plurality of resistance heating elements on one main surface or inside of a plate-like ceramic body, and a mounting surface on which the wafer is placed on the other main surface. Then, three or more peripheral convex portions are provided in the peripheral portion of the placement surface, and an inner convex portion having a height lower than the convex portion is provided inside the peripheral convex portion. And the protrusion height from the above-mentioned placement surface of the above-mentioned inside convex part is 0.05-0.5 mm, and the above-mentioned inside convex part is an inscribed circle inscribed in the above-mentioned peripheral convex part from the center of the above-mentioned placement surface Are arranged concentrically at least one in the range of 0.5 times the diameter and at least three in the range of 0.5 to 1 times the diameter of the inscribed circle. Thereby, the temperature difference in the wafer W surface can be reduced. Furthermore, the response time until the temperature of the wafer W surface during the transition is stabilized can be reduced.
[0136]
Further, by attaching the members constituting the convex portion of the peripheral portion to the concave portion of the mounting surface, the temperature in the wafer W surface can be further reduced, and the response time at the time of transition can be reduced.
[0137]
Further, when the thermal conductivity of the peripheral convex portion is 20 W / (m · K) or more and twice or less than the thermal conductivity of the plate-like ceramic body, the temperature difference on the surface of the wafer W is reduced and the temperature response time is reduced.
[0138]
Furthermore, it is preferable that a part of the peripheral convex portion is provided inside a circumscribed circle surrounding the resistance heating element of the plate-like ceramic body.
[Brief description of the drawings]
1A is a cross-sectional view showing an example of a wafer support member of the present invention, and FIG. 1B is a plan view of the same.
FIGS. 2A to 2C are enlarged sectional views of peripheral convex portions in a wafer support member of the present invention.
3A and 3B are schematic plan views showing the shape of a resistance heating element zone in the wafer support member of the present invention.
FIG. 4 is a schematic plan view showing the shape of a resistance heating element in the wafer support member of the present invention.
FIG. 5 is a schematic plan view showing the shape of a resistance heating element in the wafer support member of the present invention.
FIG. 6 is a cross-sectional view showing an example of another wafer support member of the present invention.
FIG. 7 is a cross-sectional view showing an example of a conventional wafer support member.
FIG. 8 is a schematic plan view showing the shape of a resistance heating element of a conventional wafer support member.
[Explanation of symbols]
1, 71: Wafer support member
2, 72: Plate-shaped ceramic body
3, 73: Placement surface
4: Peripheral convex part
5, 75: Resistance heating element
6: Feeder
7: Soaking plate
8: Inner convex part
9: recess
10: Bolt
11, 77: Feeding terminal
12: Guide member
16: Bolt
17: Contact member
18: Elastic body
19, 79: Metal case
20: Nut
21: Bottom
23: Hole
24: Gas injection port
25: Wafer lift pin
26: Through hole
27: Thermocouple
28: Guide member
W: Semiconductor wafer

Claims (5)

板状セラミックス体の一方の主面または内部に複数の抵抗発熱体を備え、他方の主面にウェハを載せる載置面を備えたウェハ支持部材であって、上記載置面の周辺部に３個以上の周辺凸部を設け、該周辺凸部の内側に該周辺凸部より高さの低い内側凸部を設けるとともに、上記内側凸部の上記載置面からの突出高さは０．０５〜０．５ｍｍであり、上記内側凸部は、上記載置面の中心から上記周辺凸部に内接する内接円の直径の０．５倍の範囲内に少なくとも１個、上記内接円の直径の０．５〜１倍の範囲内に少なくとも３個以上それぞれ同心円状に配置されていることを特徴とするウェハ支持部材。A wafer support member comprising a plurality of resistance heating elements on one main surface or inside of a plate-like ceramic body, and a mounting surface on which the wafer is placed on the other main surface, wherein 3 on the periphery of the mounting surface pieces or more peripheral protrusion provided Rutotomoni provided lower inner protrusion height than the peripheral projections on the inner side of the peripheral projecting portion, the projecting height from the mounting surface on said inner convex portion 0. The inward convex portion is at least one in the range of 0.5 times the diameter of the inscribed circle inscribed in the peripheral convex portion from the center of the placement surface. A wafer support member , wherein at least three or more concentric circles are arranged in a range of 0.5 to 1 times the diameter of each . 上記周辺凸部を構成する部材は、上記載置面に形成した凹部に取り付けられたことを特徴とする請求項１記載のウェハ支持部材。The peripheral protrusion constituting member, the wafer support member of claim 1, wherein a mounted in a recess formed in the mounting surface. 上記周辺凸部は円形のセラミックスからなり、該セラミックスの熱伝導率が２０Ｗ／（ｍ・Ｋ）以上であり上記板状セラミックス体の熱伝導率の２倍より小さいことを特徴とする請求項１または２記載のウェハ支持部材。Billing the peripheral protrusion comprises a circular ceramics, characterized in that the thermal conductivity of the ceramics is less than twice the thermal conductivity of and the plate-shaped ceramic body is 20W / (m · K) or higher Item 3. A wafer support member according to Item 1 or 2. 上記周辺凸部の一部は上記抵抗発熱体を囲む外接円の内部にあることを特徴とする請求項１〜３の何れかに記載のウェハ支持部材。  4. The wafer support member according to claim 1, wherein a part of the peripheral convex portion is inside a circumscribed circle surrounding the resistance heating element. 上記抵抗発熱体の上記外接円の直径Ｄが上記板状セラミックス体の直径ＤＰの９０〜９９％であることを特徴とする請求項１〜４の何れかに記載のウェハ支持部材。The wafer support member according to any one of claims 1-4 in which the diameter D of the circumscribed circle of the resistance heating element is characterized in that 90 to 99% of the diameter DP of the plate-like ceramic body.
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JP3945527B2 (en) 2004-11-30 2007-07-18 住友電気工業株式会社 Wafer holder for wafer prober and wafer prober equipped with the same
JP2007201484A (en) * 2004-11-30 2007-08-09 Sumitomo Electric Ind Ltd Wafer holder for wafer prober, and wafer prober mounted with the same
WO2007018157A1 (en) * 2005-08-05 2007-02-15 Tokyo Electron Limited Substrate processing apparatus and substrate stage used therein
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JP2008198800A (en) * 2007-02-13 2008-08-28 Bridgestone Corp Heat treatment tool
JP2010258170A (en) * 2009-04-23 2010-11-11 Tokyo Electron Ltd Substrate holding member, substrate transfer arm, and substrate carrier
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JP6730084B2 (en) * 2016-05-06 2020-07-29 日本特殊陶業株式会社 Heating member and electrostatic chuck
KR102053593B1 (en) * 2017-11-29 2019-12-09 주식회사 테스 Movement method of Lift pin and Substrate process apparatus
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