JP2005050834A - Wafer supporting member - Google Patents

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JP2005050834A
JP2005050834A JP2003202727A JP2003202727A JP2005050834A JP 2005050834 A JP2005050834 A JP 2005050834A JP 2003202727 A JP2003202727 A JP 2003202727A JP 2003202727 A JP2003202727 A JP 2003202727A JP 2005050834 A JP2005050834 A JP 2005050834A
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wafer
ceramic body
plate
heating element
resistance heating
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JP4646502B2 (en
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Tsunehiko Nakamura
恒彦 中村
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Kyocera Corp
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Kyocera Corp
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Abstract

<P>PROBLEM TO BE SOLVED: To solve a problem that temperature variation in the wafer surface is significant during a transient period immediately after a wafer is replaced on a planar ceramic body in a wafer heater before the temperature is settled. <P>SOLUTION: The wafer supporting member provided, on one major surface of a planar ceramic body, with a resistive heating element and, on the other major surface thereof, with a wafer mounting surface comprises a section for supplying power to the resistive heating element, and a metal case surrounding the power supply section. The resistive heating element located at the outer circumferential part of the planar ceramic body has a concentric pattern, the mounting surface is protruding and the circumcircle of the resistive heating element has a diameter of 90-99% that of the planar ceramic body. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

【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や特許文献２には、図８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、板状セラミック体７２の下面に、例えば図９に示すような同心円状の抵抗発熱体７５を備えるようになっていた。
【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るようになっていた。
【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、抵抗発熱体７５の抵抗分布を調整したり、抵抗発熱体７５の温度を分割制御することが行われている。また、熱引きを発生し易い構造の特許文献３や特許文献４に記載のウェハ支持部材では、ウェハＷの周辺域の発熱域を増大させる等の提案がなされていた。
【０００８】
近年半導体配線の微細化の為に用いられるようになってきた化学増幅型レジストの熱処理に於いては、ウェハＷを板状セラミックス体７２の上に差し替えした際に温度が安定するまでの過渡時における、ウェハＷ面内の温度バラツキが、露光後のレジストの化学増幅処理に極めて重要であり、従来に増して、緻密かつ応答性の良い温度制御が必要となってきた。
【０００９】
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、定常時のウェハＷの面内温度差を均一にすることが重要である。ウェハＷの面内温度差を小さくするため、発熱抵抗体７５の抵抗分布を調整したり、発熱抵抗体７５の温度を分割制御したり、熱引きを発生したりするような構造部を接続する場合、その接続部の発熱量を増大させる等の提案がされていた。
【００１０】
特許文献５には、載置面７３からウェハを浮かせて支持するために３個の支持ピン８２を設置し、この位置を調整することにより、ウェハＷの反りを発生させることにより載置面７３との間隔を調整し、ウェハＷの温度を均一にすることが示されていた。
【００１１】
また、ウェハＷを載せる載置面を凸形状としてウェハＷ面の過渡温度特性を改善したウェハ支持部材が開示されている（特許文献６）。
【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
【００１４】
【特許文献２】
特開２００１−３１３２４９号公報
【００１５】
【特許文献３】
特開２００２−７６１０２号公報
【００１６】
【特許文献４】
特許第２５２７８３６号公報
【００１７】
【特許文献５】
特開平１０−２２３６４２号広報
【００１８】
【特許文献６】
特開２００２−８３８５８号公報
【００１９】
【発明が解決しようとする課題】
しかしながら、特許文献５に示すウェハ加熱装置は、ウェハを均一に加熱するために、ウェハＷの反りを利用して調整するようにしているが、載置面７３に温度差があり、その温度差は載置面７３内全体に一様でなく、ウェハＷの反りでこの温度差を補正しても十分補正できず温度差がまだ大きいとの課題があった。このようにウェハＷと載置面７３の間の間隔が一定でないと、ウェハＷを載せ替えた際の昇温過渡時に、前記間隔が小さい部分は板状セラミックス体７２の昇温の影響を大きく受けて速やかに温度が高めになり、逆に前記間隔が大きい部分はウェハＷの温度が遅れ気味に上昇するので、両者の間で温度差が大きくなるという問題があった。最近のレジストにおいては、この温度差が成膜バラツキや、レジスト膜の反応状態を不均一にしてしまうという問題があった。
【００２０】
特に、近年、細密化が進み、低温側での温度依存性の高いレジストが普及されており、ウェハが載置面７３へ載置される直後でウェハＷの温度が室温から設定温度に達するまでのウェハＷ面内の最大温度差が６℃以下と小さいことが望まれている。
【００２１】
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。
【００２２】
しかしながら、特許文献１や２に紹介されている装置では、樹脂リング７４としてフッ素樹脂が用いられるが、固定ボルト８０による押圧により変形し易く板状セラミックス体７２が傾いたりして位置精度良く設置できないことから過渡時のウェハ面内の温度差が大きいとの課題があった。
【００２３】
また、特許文献６に記載のように載置面を凸形状とてウェハ温度の過渡特性を改善しているが、更なる過渡特性の改善が望まれている。
【００２４】
【課題を解決するための手段】
本発明者等は、上記の課題について鋭意検討した結果、板状セラミックス体の一方の主面に抵抗発熱体を備え、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、前記抵抗発熱体に電力を供給する給電部と、該給電部を囲む金属ケースとを有し、前記板状セラミックス体の外周部に位置する前記抵抗発熱体は同心円状のパターンを有し、上記載置面が凸状で、且つ前記抵抗発熱体の外接円の直径が前記板状セラミックス体の直径の９０〜９９％であることを特徴とする。
【００２５】
また、前記凸状の載置面の突出量が５〜９０μｍであることを特徴とする。
【００２６】
また、前記板状セラミック体の周辺部をリング状に支持して前記金属ケースと接続する接触部材を備えていることを特徴とする。
【００２７】
また、前記接触部材が前記板状セラミックス体と接する巾が０．１〜１３ｍｍであることを特徴とする。
【００２８】
また、前記接触部材の熱伝導率が前記板状セラミックス体の熱伝導率より小さいことを特徴とする。
【００２９】
また、前記接触部材のヤング率が１ＧＰａ以上で、板状セラミックス体のヤング率より小さいことを特徴とする。
【００３０】
また、前記接触部材の断面が円形状であることを特徴とする。
【００３１】
また、前記接触部材の断面の直径が１ｍｍ以下であることを特徴とする。
【００３２】
また、前記抵抗発熱体は、前記外接円に接する円弧状パターンと、該円弧状パターンに連続して繋がった連結パターンとを備え、前記外接円の一部に前記円弧状パターンのない空白域が存在し、この空白域の間隔が、前記板状セラミックス体の直径と前記外接円の直径との差より小さいことを特徴とする。
【００３３】
また、前記円弧状パターンの線幅は、前記円弧状パターンに繋がる前記連結パターンの線幅と同等或いは大きいことを特徴とする。
【００３４】
また、前記板状セラミックス体の厚みが１〜７ｍｍで、前記抵抗発熱体の厚みが５〜７０μｍであるとともに、前記抵抗発熱体の外接円の面積に対する抵抗発熱体の面積の比率が５〜５０％であることを特徴とする。
【００３５】
【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。
【００３６】
図１（ａ）は本発明に係るウェハ支持部材１の１例を示す断面図であり、図１（ｂ）は図１（ａ）の板状セラミックス体２が凸形状であることを示す模式図である。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、該抵抗発熱体５に電気的に接続する給電部６を具備したヒータ板１００を備え、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。
【００３７】
また、ウェハリフトピン２５は板状セラミック体２を貫通する孔を通してウェハＷを上下に移動させて、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。
【００３８】
尚、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、ウェハＷの片当たり等による温度バラツキを防止する。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。
【００３９】
図２は本発明に掛かるウェハ支持部材１の他の実施例を示す断面図で、図１と異なり、板状セラミックス体２の外周面１３に接続部材１７を介して金属ケースと固定してある。
【００４０】
図３は抵抗発熱体５のパターン形状の１例を示し、抵抗発熱体５の周辺部は同心円状をした円弧状パターン５ａとこれらと連続して繋がっている連結パターン５ｂからなり、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５は同心状の円弧状パターン５ａを有する事が好ましく、載置面３を均一に加熱できるパターン形状であれば良い。また、均熱性を改善するため、周辺部に４個と中心部に２個の合計６個のパターンに抵抗発熱体５を分割している。またパターンの線幅や粗密を調整し、発熱量の密度に分布をつけて均熱性を改善しても良い。また、抵抗発熱体５の外接円Ｃの直径ＤＣはウェハＷの直径ＤＷと同等或いは直径ＤＣが直径ＤＷより大きいことがウェハＷ面内の温度差を小さくする上で好ましい。
【００４１】
図４は本発明の抵抗発熱体５のパターン形状の他の例を示す。抵抗発熱体５は周辺部に４個と中心部に１個の合計５個のパターンに分割された例を示す。
【００４２】
また、図５は抵抗発熱体５が１個のパターン形状からなる他の例を示す。
【００４３】
本発明のウェハ支持部材１は、板状セラミックス体２の一方の主面にウェハＷを載せる載置面３が凸状で、且つ前記抵抗発熱体５の外接円Ｃの直径ＤＣが前記板状セラミックス体２の直径Ｄの９０〜９９％であることが重要である。
【００４４】
載置面３が凸状であると、加熱した板状セラミックス体２に室温に冷えたウェハＷを載せると、ウェハＷ面内の温度差が小さい状態で加熱されることから好ましい。
【００４５】
更に、前記抵抗発熱体５の外接円Ｃの直径ＤＣが前記板状セラミックス体２の直径Ｄの９０〜９９％であると、載置面３が凸状による相乗効果が発現し、ウェハＷを載置面３に載せた瞬間からウェハＷが加熱され温度が一定の温度に達するまでのウェハＷ面内の温度差が小さくなる。その結果、例えばウェハＷ上のレジスト膜の面内での均一性が極めて優れたものとなることが判明した。
【００４６】
載置面３が凸状で抵抗発熱体５の外接円Ｃの直径ＤＣが板状セラミックス体２の直径Ｄの９０％より小さいと、ウェハＷを板状セラミックス体２に載せた瞬間板状セラミックス体２の熱が奪われるが、板状セラミックス体２の周辺はウェハＷが対向していないことから温度の低下が小さいことから、ウェハＷの中心より周辺の温度が高い状態で加熱されながら設定温度に収斂する。この理由からウェハＷ面内の過渡時の温度差が大きくなる虞があるからである。また、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。更に、板状セラミックス体２の直径Ｄ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Ｄに比較して小さくなり、ウェハＷを加熱する電力に対するウェハ加熱効率が悪くなる。
【００４７】
載置面３が凸状で抵抗発熱体５の外接円Ｃの直径ＤＣが板状セラミックス体２の直径Ｄ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に大量に流れるとともにウェハＷと対向しない板状セラミックス体２の周辺部の熱容量が小さいことから、板状セラミックス体２にウェハＷを載せた瞬間、ウェハＷの周辺の温度が下がりすぎてウェハＷ面内の温度差が大きな状態で加熱される虞がある。
【００４８】
また、ウェハＷ温度が定常な状態で、外周部の円弧状パターン５ａ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５ａ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５ａ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からである。
【００４９】
より好ましくは、抵抗発熱体５の外接円Ｃの直径ＤＣが板状セラミックス体２の直径Ｄの９２〜９７％である。
【００５０】
特に、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が支える図１のウェハ支持部材１の場合、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ＤＣが板状セラミックス体２の直径Ｄの９２〜９５％であり、更に好ましくは９３〜９５％である。
【００５１】
一方、板状セラミックス体２の外周面１３を覆うように金属ケース１９が接続した図２のウェハ支持部材の場合には、抵抗発熱体５の外接円Ｃの直径ＤＣが板状セラミックス体２の直径Ｄの９５〜９８％が好ましく、更に好ましくは９６〜９７％である。
【００５２】
尚、本発明のウェハ支持部材１は板状セラミックス体２の周辺部下面に金属ケース１９を接続したり、板状セラミックス体２の外周面１３で金属ケースと接続した例で説明したが、周辺部下面と外周面との両方同時に金属ケース１９と接続したウェハ支持部材１も含まれることは当然である。
【００５３】
また、凸状の載置面３の突出量ｔｏが５〜９０μｍであることが好ましい。
【００５４】
突出量が５μｍを下回ったり、載置面３が凹状であると、ウェハＷの中心部における板状セラミックス体２との距離が周辺部より大きくなり、載置面３からの熱の伝達が遅くなり、載置面３にウェハＷを載せた直後の過渡時のウェハＷの中心部の温度が低くなる虞がある。
【００５５】
また、前記突出量が９０μｍを超えると、板状セラミックス体２の中心部と周辺部の高低差が大きくなり過ぎて、ウェハＷの周辺部と板状セラミックス体２との距離が中心部に比べ大きくなり、中心部に比べ周辺部の温度が低く、温度差が大きな状態で加熱される虞があるからである。
【００５６】
より好ましくは、凸状の載置面３の突出量が２０〜７０μｍであり更に好ましくは３０〜５０μｍである。尚、この突出量はウェハＷサイズにも関連し、概ね直径３００ｍｍ以上大きさのウェハＷでより効果が大きくなることが判明した。
【００５７】
図６は、図１に示すウェハ支持部材１のリング状の接触部材１７付近を示す拡大断面図である。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ことからウェハＷの過渡時の温度差が小さくなり好ましい。また、ウェハＷの面内の定常時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。
【００５８】
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室温に冷えたウェハＷを載置面３に載せた瞬間、ウェハＷ周辺部の温度が低く加熱され、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。
【００５９】
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、過渡時のウェハＷ面内の温度差が小さく迅速に温度を変更することが容易となる。
【００６０】
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、接触部材１７を介して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、ウェハＷを板状セラミックス体２に載せた直後のウェハＷ面内温度温度差に金属ケース１９の熱引けが悪影響する効果が小さく好ましい。
【００６１】
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。
【００６２】
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。
【００６３】
尚、接触部材をフッ素系に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。
【００６４】
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。
【００６５】
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とともにウェハＷの過渡時の面内温度差小さくなり好ましい。
【００６６】
更に、本発明のウェハ支持部材１において、抵抗発熱体５の外接円Ｃと接する円弧状パターン５ａと、該円弧状パターンと連続して繋がった連結パターン５ｂとを備え、前記外接円Ｃの一部に前記円弧状のパターンのない空白域Ｐが存在し、この空白域Ｐの間隔Ｓが、前記板状セラミックス体の直径Ｄと前記外接円Ｃの直径ＤＣとの差（以下、Ｌと略する）より小さいことが好ましい。特に、ウェハＷを載置面３に載せた直後のウェハＷ面内の温度差を小さくする上で好ましいことが判明した。
【００６７】
間隔ＳがＬより大きいと空白域Ｐの熱が板状セラミックス体の周辺部へ流れ空白域Ｐの温度が下がる虞がある。しかし、間隔ＳがＬより小さいと空白域Ｐの温度が下がり難く板状セラミックス体２の載置面３に載せたウェハＷの周辺部の一部の温度が低下せずウェハＷ面内の温度差が小さくなり好ましい。
【００６８】
そこで、前記円弧状パターンの線幅は、前記円弧状パターンに繋がる前記連結パターンの線幅と同等或いは大きいことが好ましい。
【００６９】
上記空白域Ｐの温度を下げないためには、空白域の温度を上げる必要があり、空白域を加熱する連結パターン５ｂの抵抗を同等か或いは大きくして発熱量を増大すると、空白域Ｐの温度が下がる虞が小さくなり、ウェハＷの面内温度が均一となり好ましい。印刷法等で作成した抵抗発熱体５で断面が面状の場合、円弧状パターン５ａの線幅Ｗｐより連結パターン５ｂの線幅Ｗｓを小さくすることで連結パターン５ｂの抵抗を大きくすることができ、連結パターン５ｂの温度を円弧状パターン５ａの温度より高めることでウェハＷの面内温度を均一とすることができる。
【００７０】
また、板状セラミックス体２の厚みは１〜７ｍｍで、上記抵抗発熱体５の厚みは５〜７０μｍ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。
【００７１】
即ち、抵抗発熱体５を囲む外接円Ｃの面積に対し、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。
【００７２】
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、板状セラミック体２は変形し難いセラミック焼結体からなるものの、その板状セラミック体２の厚み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。
【００７３】
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。
【００７４】
より具体的には、抵抗発熱体５は外周部に相対抗する対抗領域を有し、上記対抗領域の間隔Ｓ１が０．５ｍｍ以上で、上記板状セラミックス体２の板厚の３倍以下であることが好ましい。上記対抗領域の間隔Ｓ１が０．５ｍｍ以下では抵抗発熱体５を印刷し形成する際に抵抗発熱体５の対抗領域でひげ状の突起が発生しその部分が短絡する虞がある。また、上記対抗領域の間隔Ｓ１が板状セラミックス体２の厚みの３倍を越えると、対抗領域Ｓ１に対応するウェハＷの表面にクールゾーンが発生しウェハＷの面内温度差を大きくする虞があるからである。
【００７５】
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５〜７０μｍとすることが好ましい。
【００７６】
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７０μｍ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、板状セラミック体５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。
【００７７】
次に、更に詳細な他の構成や製法について説明する。
【００７８】
本発明に係るウェハ支持部材１の板状セラミックス体２の厚みｔは１〜７ｍｍで、１００〜２００℃のヤング率が２００〜４５０ＭＰａである板状セラミック体２からなることが好ましい。
【００７９】
１００〜２００℃のヤング率が２００〜４５０ＭＰａである板状セラミック体２の材質としては、炭化珪素、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、板状セラミック体２の材質として好適である。
【００８０】
尚、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】
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測温素子２７を設置してある。
【００８２】
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。
【００８３】
板状セラミックス体２は、有底の金属ケース１９の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。
【００８４】
さらに、載置面が凸状になるように形成するには、板状セラミックスに抵抗発熱体５を形勢したヒータ板１００を金属ケース１９に接触部材１７を介して固定した後、導通端子１１の押圧力により調整することができる。急速昇温および急速降温を可能にするため、ヒータ板１００の厚みは１〜７ｍｍの範囲に調整されており、その一方、ヒータ板１００の外形は２００ｍｍから３００ｍｍへのウェハＷの大型化に伴い直径２３０ｍｍから３３０ｍｍへと大型化する傾向にある。ヒータ板１００の大面積化と薄肉化により、ヒータ板１００は、導通端子１１の押圧力によって変形するようになってきている。
【００８５】
そこで、この押圧力を利用して、ヒータ板１００の突出量を調整することができる。場合によっては、ヒータ板１００を載置面３側が平坦もしくは凹になるように加工した後、導通端子１１の押圧力によりヒータ板１００の反りを狙いの５〜９０μｍの凸状とすることができる。
【００８６】
また、ヒータ板１００の載置面３側に、ヒータ板１００の熱膨張係数より０．８〜１．８×１０−６／℃大きな熱膨張係数を有するガラス層を４０〜３００μｍ厚み形成することにより、載置面３側が凸になるような反りを生成させても良い。
【００８７】
ガラス層の厚みを４０μｍ未満にすると、反りに対する影響が小さくなるので所望の効果が期待できなくなる。また、ガラス層の厚みが３００μｍを越える厚みにすると、載置面３側からの熱伝達が遅くなりウェハＷの昇温速度が遅くなってしまうので好ましくない。
【００８８】
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のウェハ支持部材１の製法と構成に付いて述べる。
【００８９】
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。
【００９０】
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。
【００９１】
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。
【００９２】
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。
【００９３】
一方、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。
【００９４】
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＋１×１０−７／℃〜＋６×１０−７／℃の範囲で大きな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り、載置面３側を凸状に形成することが容易となる。
【００９５】
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。
【００９６】
図９に示すように、板状セラミック体２２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が難しいことから好ましくない。
【００９７】
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。
【００９８】
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。
【００９９】
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体２の熱膨張係数に近づけるには、板状セラミック体２の熱膨張係数より大きな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。
【０１００】
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。
【０１０１】
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。
【０１０２】
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。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側が凹状に反る恐れがあるからである。
【０１０３】
さらに、絶縁層上に被着する抵抗発熱体５材料としては、金（Ａｕ）、銀（Ａｇ）、銅（Ｃｕ）、パラジウム（Ｐｄ）等の金属単体を、蒸着法やメッキ法にて直接被着するか、あるいは前記金属単体や酸化レニウム（Ｒｅ２Ｏ３）、ランタンマンガネート（ＬａＭｎＯ３）等の導電性の金属酸化物や上記金属材料を樹脂ペーストやガラスペーストに分散させたペーストを用意し、所定のパターン形状にスクリーン印刷法等にて印刷したあと焼付けして、前記導電材を樹脂やガラスから成るマトリックスで結合すれば良い。マトリックスとしてガラスを用いる場合、結晶化ガラス、非晶質ガラスのいずれでも良いが、熱サイクルによる抵抗値の変化を抑えるために結晶化ガラスを用いることが好ましい。
【０１０４】
ただし、抵抗発熱体５材料に銀（Ａｇ）又は銅（Ｃｕ）を用いる場合、マイグレーションが発生する恐れがあるため、このような場合には、抵抗発熱体５を覆うように絶縁層と同一の材質からなるコート層を４０〜４００μｍ程度の厚みで被覆しておけば良い。
【０１０５】
更に、抵抗発熱体５への給電方法については、抵抗発熱体５に金や銀、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が、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載置面３を凸状にするとともに接続を確保し給電することが好ましい。これは、１〜７ｍｍ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、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。
【０１０６】
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等の測温素子２７により測定する。測温素子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を使用することが好ましい。この熱電対の先端部は、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。
【０１０７】
また、板状セラミック体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。
【０１０８】
【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。
【０１０９】
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。
【０１１０】
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。
【０１１１】
そして、得られた窒化アルミニ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。
【０１１２】
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。
【０１１３】
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３１５ｍｍ〜３４５ｍｍ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。
【０１１４】
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、更にその外側に４つのパターンからなる計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。そして抵抗発熱体を覆うようにコート層を形成し、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。
【０１１５】
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。
【０１１６】
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。
【０１１７】
尚、凸状の載置面の突出量は導通端子により板状セラミックス体を押圧する力と前記のコート層の厚みを変えて調整した。
【０１１８】
また、板状セラミックス体の周辺部下面を支持する支持構造▲１▼と、板状セラミックス体の外周面を支持する支持構造▲２▼との２つの構造でウェハ支持部材を作製した。尚、支持構造▲１▼では、板状セラミックス体の直径と金属ケースの外形である直径を同じとした。
【０１１９】
尚、接触部材はリング状でその断面は四角形とした。台形状の断面の大きさは、厚み１ｍｍで幅５ｍｍとした。また、接触部材の材質はＴｉやチタン合金を用いた。作製した各種のウェハ支持部材を試料Ｎｏ．１〜１２とした。
【０１２０】
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保持した。その後ウェハＷを取り外した。そして、前記測温用ウェハＷを用いてウェハＷ面が同じ室温のウェハＷを載置面に載せ、ウェハＷの温度が２００℃に達するまでの各測温抵抗体の温度を測定した。そして室温２５℃から２００℃±０．５℃の範囲になるまでの時間を応答時間として測定し、それまでの各測温抵抗体の最大温度差を過渡時のウェハが２００℃に達するまでのウェハ面内の最大温度差（℃）とした。
【０１２１】
また、３０℃から２００℃に５分で昇温し５分間保持した後、３０分間冷却する温度サイクルを１０００サイクル繰り返した後、室温から２００℃に設定し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。
【０１２２】
それぞれの結果は表１に示す通りである。
【０１２３】
【表１】

Figure 2005050834
【０１２４】
表１の試料Ｎｏ．１は、板状セラミックス体の直径に対する抵抗発熱体の外接円の比率が９０％であるが、載置面がー１０μｍの凹面状であることから過渡時のウェハＷ面内の最大温度差が１１．５℃と大きく、また、ウェハの温度差は０．５℃と大きく、特に応答時間が６５秒と大きく何れの特性値も好ましくなかった。
【０１２５】
また、試料Ｎｏ．１２は板状セラミックス体の直径に対する抵抗発熱体の外接円の比率が９９．５％と大きくウェハの面内温度差は２．１℃と大きく、応答時間も６８秒と大きく好ましくなかった。
【０１２６】
これらに対し、載置面が凸状で、且つ抵抗発熱体の外接円の直径が板状セラミックス体の直径の９０〜９９％である試料Ｎｏ．３〜１１はウェハの面内の温度差が０．５℃未満と小さく、しかも応答時間も３８秒以下と小さく優れていることが分かる。
【０１２７】
更に、板状セラミックス体の外周部下面で金属ケースと接触部材を介して接続した支持構造▲１▼では、試料Ｎｏ．４〜６に示すように板状セラミックス体の直径に対する抵抗発熱体の外接円の比率が９２〜９５％で、ウェハ面内の最大温度差が５．５℃以下と小さく、ウェハの面内温度差が０．４０℃以下で且つ応答時間が３４秒以下と優れている。
【０１２８】
また、試料Ｎｏ．５，６は面内温度差が０．３５℃以下で応答時間も３３秒以下と小さいことから、板状セラミックス体の直径に対する抵抗発熱体の外接円の比率が９３〜９５％であるとさらに好ましいことが分る。
【０１２９】
一方、板状セラミックス体の外周部側面で金属ケースと接触部材を介して接続した支持構造▲２▼では、試料Ｎｏ．７〜１０に示すように板状セラミックス体の直径に対する抵抗発熱体の外接円の比率が９５％〜９８％で、ウェハの面内温度差が０．４４℃以下で且つ応答時間は３３秒以下と優れていた。更に、試料Ｎｏ．８，９の面内温度差はどちらも０．４０℃で応答時間が３０秒と小さいことから、板状セラミックス体の直径に対する抵抗発熱体の外接円の比率が９６％〜９７％であることがさらに好ましいことが分った。
【０１３０】
また、載置面の突出量は試料Ｎｏ．３〜１１のように５μｍから９０μｍであると好ましいことが分かった。
【０１３１】
（実施例 ２）
実施例１と同様に板状セラミックス体２を製作した。
【０１３２】
そして、有底の金属ケース１９は、直径３３０ｍｍで底面２１を構成する厚み２．０ｍｍのアルミニウムと側壁部２２を構成する厚み１．０ｍｍのアルミニウムからなり、底面２１に、ガス噴射口１２、熱電対１３、導通端子１１を所定の位置に取り付けた。また、底面２１から板状セラミックス体２までの距離は２０ｍｍとした。その後、前記有底の金属ケース１９の開口部に、板状セラミックス体２を重ね、その外周部にボルト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、接触部材１７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ウェハ支持部材１とした。接触部材１７の断面は台形状で、板状セラミックス体の周辺部を支持するリング状とした。台形状の断面の大きさは、下辺が４ｍｍで高さ２ｍｍとし上辺は０．０５〜４ｍｍと、下辺が１５ｍｍで高さ２ｍｍで上辺を５〜１５ｍｍとした接触部材をそれぞれのウェハ支持部材に取り付けた。また、接触部材の材質はチタンを用いた。作製した各種のウェハ支持部材を試料Ｎｏ．２１〜２９とした。
【０１３３】
尚、載置面３の突出量は４０μｍで一定とし、抵抗発熱体５の外接円の直径が板状セラミックス体２の直径の９５％とした。
【０１３４】
評価は、実施例１と同様に行った。
【０１３５】
それぞれの結果は表２に示す通りである。
【０１３６】
【表２】
Figure 2005050834
【０１３７】
表１から判るように、試料Ｎｏ．２１は、接触部材１７と板状セラミックス体２との接触部の巾が０．０５ｍｍと小さく応答時間やウェハの温度差は小さかったが、使用中に接触部材のエッジからと思われるパーティクルが発生しウェハ面内の最大温度差が５．６℃とやや大きく好ましくなかった。
【０１３８】
また、試料Ｎｏ．２９は接触部材１７の接触部の巾が１５ｍｍと大きくウェハ面内の最大温度差が６℃とやや大きかった。
【０１３９】
これに対し、試料Ｎｏ．２２〜２８のウェハ支持部材１は接触部材１７が板状セラミックス体２と接触する面積が０．１〜１３ｍｍであることからウェハ面内の最大温度差が４．１℃以下と小さく、ウェハの面内温度差は０．４℃以下であり、応答時間も３８秒以下と小さくより優れた特性を示すことが分かった。
【０１４０】
（実施例 ３）
実施例１と同様の板状セラミックス体２の製造工程において、酸化イットリウムの添加量を０．１〜５質量％の範囲で変化させて板状セラミックス体２を作製した。また、ＳＵＳ３０４、ＳＵＳ４０３、Ｆｅ−Ｎｉ−Ｃｏ合金（コバール）、炭素鋼、アルミニウムを用いて板状セラミックス体２と接触する接触部の巾が２ｍｍの接触部材を作製した。そして、板状セラミックス体２の熱伝導率と接触部材の熱伝導率の比が１〜１２８％となるように板状セラミックス体と接触部材を組み合わせ板状セラミックス体に上記接触部材を介してアルミニウム製の有底の金属ケースを取り付けウェハ支持部材を作製した。
【０１４１】
尚、試料Ｎｏ．３１〜３８は金属製の接触部材を用い、有底の金属ケースは直径３３０ｍｍで側壁部の板厚が１．０ｍｍ、底面の板厚が２．０ｍｍとし、深さは３０ｍｍとした。また、試料Ｎｏ．３９、４０は樹脂製の接触部材でヤング率が１ＧＰａを下回ることから台形状の接触部材の変形が大きくウェハ支持部材として使用困難であったことから、図４に示すように板状セラミックス体の外周部を覆う構造とし、有底の金属ケースは直径３４０ｍｍで側壁部の厚み１．０ｍｍ、底面の厚み２．０ｍｍとし、深さは３０ｍｍとした。
【０１４２】
そして、実施例１と同様に評価した。
【０１４３】
その結果を表３に示す。
【０１４４】
【表３】
Figure 2005050834
【０１４５】
接触部材としてＳＵＳ３０４、Ｆｅ−Ｎｉ−Ｃｏ合金、ＳＵＳ４０３、炭素鋼を用い、熱伝導率の異なる窒化アルミニウムと組み合わせ、接触部材の熱伝導率が板状セラミックス体の熱伝導率より小さい試料Ｎｏ．３１〜３７のウェハ接触部材は応答時間が３５秒以内でしかもウェハの温度差も０．３５℃以下と優れていることが分った。
【０１４６】
しかし、試料Ｎｏ．３８は接触部材の熱伝導率が板状セラミックス体より大きく、ウェハ面内の最大温度差が５．７℃と大きく、応答時間が５３秒とやや大きく、しかもウェハ面内の温度差が０．５５℃とやや大きかった。
【０１４７】
従って、接触部材の熱伝導率は板状セラミックス体の熱伝導率より小さいウェハ支持部材は応答特性やウェハの温度差が小さく優れた特性を示すことが分った。
【０１４８】
（実施例 ４）
実施例２と同様に板状セラミックス体を作製した。また、ＳＵＳ３０４、ＳＵＳ４０３、Ｆｅ−Ｎｉ−Ｃｏ合金（コバール）、炭素鋼、アルミニウム、錫、錫鉛合金を用いて板状セラミックス体と接触する接触部材の接触部の巾が０．１ｍｍでヤング率の異なる接触部材を作製した。そして、板状セラミックス体に上記接触部材を介して実施例２と同様にアルミニウム製の有底の金属ケースを取り付けウェハ支持部材を作製した。
【０１４９】
そして、実施例１と同様に評価した。
【０１５０】
その結果を表４に示す。
【０１５１】
【表４】
Figure 2005050834
【０１５２】
ヤング率が１ＧＰａ以上の接触部材からなる試料Ｎｏ．４１〜４７のウェハ支持部材は、ウェハの最大温度差が４．３℃以下で、ウェハ面内の温度差が０．３５℃以下であり、応答時間が３５秒以下と小さく好ましい特性を示すことが分った。
【０１５３】
しかし、試料Ｎｏ．４８のフッ素樹脂や繊維入り樹脂からなるウェハ支持部材はウェハの最大温度差が６℃で、ウェハ面内の温度差が０．４９℃であり、応答時間が４５秒とやや大きかった。
【０１５４】
従って、接触部材のヤング率は１ＧＰａ以上で３００ＧＰ以下であることが判明した。
【０１５５】
（実施例 ５）
実施例１と同様に板状セラミックス体を作製した。また、接触部材として炭素鋼で断面が台形のウェハ支持部材と、炭素鋼製の接触部材で断面が円形の接触部材を作製し、板状セラミックス体に上記接触部材を介してアルミニウム製の有底の金属ケースを取り付けウェハ支持部材を作製した。
【０１５６】
そして、実施例１と同様に評価した。
【０１５７】
その結果を表５に示す。
【０１５８】
【表５】
Figure 2005050834
【０１５９】
試料Ｎｏ．５１、５２の接触部材が台形のウェハ支持部材はウェハ面内の最大温度差が４．５℃、３．２℃で、ウェハ面内の温度差が０．３６℃、０．２６℃と応答時間が３５秒、２９秒であったが、図７に示す構造の試料Ｎｏ．５３，５４のように接触部材の断面が円形であるものは応答時間が２３秒、２１秒と小さく、ウェハの最大温度差も３．１℃、２．８℃と小さく、ウェハの面内温度差は０．２５℃、０．２２℃と小さくより好ましいことが分った。
【０１６０】
特に、接触部材の断面が円形で断面の直径が１ｍｍ以下のウェハ支持部材は応答時間が２１秒で且つウェハの最大温度差が２．８℃、ウェハの面内温度差が０．２２℃と更に優れた特性を示すことが分った。
【０１６１】
（実施例６）
実施例１と同様の工程で板状セラミックス体を作製した。そして、板状セラミックス体の主面に実施例１と同様の工程で抵抗発熱体を印刷した。最外周の抵抗発熱体のパターンは図４に示す最外周のパターンの構成として、抵抗発熱体として最外周の４つのパターンに接する外接円の一部に円弧状パターンのない空白域Ｐの間隔Ｓと、前記抵抗発熱体に接する外接円の直径を３１０ｍｍとして板状セラミックス体の直径を変えたウェハ支持部材を作製した。
【０１６２】
また、板状セラミックス体に上記接触部材を介してアルミニウム製の有底の金属ケースを取り付けウェハ支持部材を作製した。
【０１６３】
そして、実施例１と同様に評価した。その結果を表６に示す。
【０１６４】
【表６】
Figure 2005050834
【０１６５】
板状セラミックス体の直径と抵抗発熱体の外接円の直径との差Ｌが、空白域の間隔Ｓより大きい試料Ｎｏ．６１、６５、６７は、ウェハの最大温度差はそれぞれ５．５℃、５．４℃、５．７℃で、ウェハの面内温度差は０．４７℃、０．４５℃、０．４８℃であり、応答時間は３８、３７、３８秒とやや大きかった。
【０１６６】
これらに対し、試料Ｎｏ．６２、６３，６４、６６、６８の空白域の間隔Ｓが上記の差Ｌより小さいウェハ支持部材は、ウェハの最大温度差は３．３℃以下で、ウェハの面内温度差は０．２５℃以下と小さく、応答も２９秒以下とより優れた特性を示すことが判明した。
【０１６７】
（実施例 ７）
実施例２の試料Ｎｏ．６３と同様の構成で、抵抗発熱体の外周部の円弧状パターンの線幅とこれに繋がる連結パターンの線幅を変えたウェハ支持部材を作製し実施例２と同様の評価を行った。その結果を表３に示す。
【０１６８】
【表７】
Figure 2005050834
【０１６９】
連結パターンの線幅が円弧状パターンの線幅と同等或いは大きい試料Ｎｏ．７３，７４、７６、７７のウェハの最大温度差は２．８℃以下と小さく、ウェハの面内温度差は０．２１℃以下と小さく、しかも応答時間が２２秒以下と優れている事が判明した。
【０１７０】
更に、連結パターンの線幅が円弧状のパターンの線幅より小さい試料Ｎｏ．７４、７７のウェハの最大温度差は２．５℃、２．６９℃と小さく、面内温度差が０．２℃と小さく、しかも応答時間が２０秒と極めて優れている事が判明した。
【０１７１】
これらに対して、試料Ｎｏ．７１、７２、７５はウェハの最大温度差が５．１〜５．３℃とやや大きく、ウェハの面内温度差が０．４２〜０．４５℃で応答時間も３３〜３５秒とやや大きかった。
【０１７２】
従って、ウェハ支持部材において、前記円弧状パターンの線幅は、前記円弧状パターンと繋がる前記連結パターンの線幅と、同等或いは大きいことによりウェハの温度差が小さく応答時間の小さい優れたウェハ支持部材を提供できることが判明した。
【０１７３】
（実施例 ８）
実施例１と同様に板状セラミックス体を作製した。
【０１７４】
ただし、ペーストの印刷厚みは２０μｍとし、また、抵抗発熱体を囲む外接円に対し、抵抗発熱体の占める面積の比率を異ならせたものを用意した。
【０１７５】
そして、実施例１と同様に評価した。その結果を表８に示す。
【０１７６】
【表８】
Figure 2005050834
【０１７７】
この結果、試料Ｎｏ．８０のように、抵抗発熱体を囲む外接円に対し、抵抗発熱体の占める面積の比率が５％を下回り３％である試料は、ウエハの面内の最大温度差が５．９℃とやや大きく、ウェハの面内温度差が０．４８℃で応答時間は３９秒とやや大きかった。また、試料Ｎｏ．８９のように、抵抗発熱体を囲む外接円に対し、抵抗発熱体の占める面積の比率が５０％を越え６０％であると、ウエハの一部に温度の高いホットエリヤが現れ、ウエハの面内の最大温度差が５．８℃と大きく、ウェハの面内温度差は０．４５℃で、応答時間は３４秒とやや大きかった。
【０１７８】
これに対し、試料Ｎｏ．８１〜８８に示すように、抵抗発熱体の外接円に対して、抵抗発熱体の占める面積の比率が５〜５０％である試料は、ウエハの面内の最大温度差が４．８℃以下と小さく、ウェハの面内温度差が０．３９℃以下と小さく、応答時間も３４秒以下と小さく優れた特性を示した。
【０１７９】
また、試料Ｎｏ．８２〜８６のように、抵抗発熱体の外接円に対して、抵抗発熱体の占める面積の比率を１０〜３０％とすることで、ウエハの面内の最大温度差を３．６℃以内で、ウェハの面内温度差が０．２８以下と小さく、応答時間も２９秒以下と更に優れていることが判明した。
【０１８０】
さらには試料Ｎｏ．８３〜８５のように、抵抗発熱体の外接円に対して、抵抗発熱体の占める面積の比率を１５〜２５％とすることでウエハの面内の最大温度差を１．９℃以内とし、ウェハの面内温度差が０．１７℃以下となり応答時間が２２秒以下と極めて優れていることが分かった。
【０１８１】
【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に抵抗発熱体を備え、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、前記抵抗発熱体に電力を供給する給電部と、該給電部を囲む金属ケースとを有し、前記板状セラミックス体の外周部に位置する前記抵抗発熱体は同心円状のパターンを有し、上記載置面が凸状で、且つ前記抵抗発熱体の外接円の直径が前記板状セラミックス体の直径の９０〜９９％とすることにより板状セラミックス体上にウェハを差し替えした直後の温度が安定するまでの過渡時のウェハ面内の温度ばらつが小さく、ウェハ面内の温度差が小さく温度応答特性の優れたウェハ保持部材が得られる。
【０１８２】
更に、前記ウェハ支持部材において、前記外接円と接する円弧状パターンと、該円弧状パターンと連続して繋がった連結パターンとを備え、前記外接円の一部に前記円弧状のパターンのない空白域の間隔が、前記板状セラミックス体と前記外接円の直径との差より小さくすることでウェハの均熱性の高いウェハ支持部材が得られる。
【図面の簡単な説明】
【図１】（ａ）は本発明のウェハ加熱装置の一例を示す断面図、（ｂ）は板状セラミックス体を示す模式図である。
【図２】本発明の他のウェハ加熱装置の一例を示す断面図である。
【図３】本発明の抵抗発熱体の形状を示す概略図である。
【図４】本発明の他の抵抗発熱体の形状を示す概略図である。
【図５】本発明の他の抵抗発熱体の形状を示す概略図である。
【図６】本発明のウェハ加熱装置の一例を示す断面図であり、接触部材の付近の拡大図を示す。
【図７】本発明のウェハ加熱装置の一例を示す断面図であり、接触部材の付近の拡大図を示す。
【図８】従来のウェハ加熱装置の一例を示す断面図である。
【図９】従来の抵抗発熱体の形状を示す概略図である。
【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
５、７５：抵抗発熱体
６：給電部
８：支持ピン
１０：ガイド部材
１１、７７：給電端子
１３：外周面
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：測温素子
２８：従来のガイド部材
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 and Patent Document 2 propose a wafer support member as shown in FIG.
[0005]
The wafer support member 71 includes a plate-shaped ceramic body 72 and a metal case 79 as main components, and nitride ceramics or carbide is formed in an opening of a bottomed metal case 79 made of a metal such as aluminum. A plate-shaped ceramic body 72 made of ceramics is fixed with a bolt 80 via a heat insulating connecting member 74 made of a resin, and the upper surface thereof serves as a mounting surface 73 on which the wafer W is placed, and the lower surface of the plate-shaped ceramic body 72 For example, a concentric resistance heating element 75 as shown in FIG. 9 is provided.
[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 to be 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, until now, in order to reduce the temperature difference in the surface of the wafer, the resistance distribution of the resistance heating element 75 is adjusted, or the temperature of the resistance heating element 75 is divided and controlled. Further, in the wafer support members described in Patent Document 3 and Patent Document 4 having a structure that easily generates heat, proposals have been made to increase the heat generation area in the peripheral area of the wafer W.
[0008]
In the heat treatment of a chemically amplified resist that has been used for miniaturization of semiconductor wiring in recent years, when the wafer W is replaced on the plate-like ceramic body 72, the temperature is stabilized until it becomes stable. The temperature variation in the surface of the wafer W is extremely important for the chemical amplification process of the resist after exposure, and more precise and responsive temperature control is required than ever before.
[0009]
In such a wafer support member 71, in order to form a uniform film on the entire surface of the wafer W or to make the heating reaction state of the resist film uniform, the in-plane temperature difference of the wafer W in the steady state is made uniform. It is important to. In order to reduce the in-plane temperature difference of the wafer W, a structure that adjusts the resistance distribution of the heating resistor 75, controls the temperature of the heating resistor 75 in a divided manner, or generates heat is connected. In some cases, proposals have been made to increase the amount of heat generated at the connecting portion.
[0010]
In Patent Document 5, three support pins 82 are provided to float and support the wafer from the mounting surface 73, and by adjusting the position, the mounting surface 73 is caused by warping the wafer W. It has been shown that the temperature of the wafer W is made uniform by adjusting the distance between the
[0011]
Further, a wafer support member is disclosed in which the mounting surface on which the wafer W is placed has a convex shape and the transient temperature characteristics of the wafer W surface are improved (Patent Document 6).
[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
[0014]
[Patent Document 2]
JP 2001-313249 A
[0015]
[Patent Document 3]
JP 2002-76102 A
[0016]
[Patent Document 4]
Japanese Patent No. 2527836
[0017]
[Patent Document 5]
Japanese Laid-Open Patent Publication No. 10-223642
[0018]
[Patent Document 6]
JP 2002-83858 A
[0019]
[Problems to be solved by the invention]
However, in the wafer heating apparatus shown in Patent Document 5, adjustment is performed using the warp of the wafer W in order to uniformly heat the wafer, but there is a temperature difference on the mounting surface 73, and the temperature difference. Is not uniform over the entire mounting surface 73, and even if this temperature difference is corrected by warpage of the wafer W, the temperature difference cannot be sufficiently corrected. As described above, if the interval between the wafer W and the mounting surface 73 is not constant, the portion where the interval is small greatly affects the temperature increase of the plate-like ceramic body 72 when the wafer W is replaced. In response to this, the temperature is quickly increased, and conversely, the temperature of the wafer W rises in a delayed manner in the portion where the interval is large, so that there is a problem that the temperature difference between the two becomes large. In recent resists, there is a problem that this temperature difference causes variations in film formation and makes the reaction state of the resist film non-uniform.
[0020]
In particular, in recent years, with the progress of miniaturization, resists with high temperature dependence on the low temperature side have become widespread, and immediately after the wafer is placed on the placement surface 73, the temperature of the wafer W reaches the set temperature from room temperature. It is desired that the maximum temperature difference in the wafer W surface is as small as 6 ° C. or less.
[0021]
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.
[0022]
However, in the devices introduced in Patent Documents 1 and 2, a fluororesin is used as the resin ring 74, but the plate-shaped ceramic body 72 is easily deformed by the pressing by the fixing bolt 80 and cannot be installed with high positional accuracy. Therefore, there is a problem that the temperature difference in the wafer surface during the transition is large.
[0023]
Further, as described in Patent Document 6, the mounting surface has a convex shape to improve the transient characteristic of the wafer temperature, but further improvement of the transient characteristic is desired.
[0024]
[Means for Solving the Problems]
As a result of intensive studies on the above-mentioned problems, the present inventors have found a wafer support member having a resistance heating element on one main surface of a plate-like ceramic body and a mounting surface on which the wafer is placed on the other main surface. And a metal case surrounding the power supply portion, and the resistance heat generator located on the outer peripheral portion of the plate-like ceramic body has a concentric pattern. The placement surface is convex, and the diameter of the circumscribed circle of the resistance heating element is 90 to 99% of the diameter of the plate-like ceramic body.
[0025]
Further, the protruding amount of the convex mounting surface is 5 to 90 μm.
[0026]
In addition, a contact member that supports a peripheral portion of the plate-like ceramic body in a ring shape and is connected to the metal case is provided.
[0027]
Moreover, the width | variety with which the said contact member contacts the said plate-shaped ceramic body is 0.1-13 mm, It is characterized by the above-mentioned.
[0028]
Further, the thermal conductivity of the contact member is smaller than the thermal conductivity of the plate-like ceramic body.
[0029]
The contact member has a Young's modulus of 1 GPa or more and is smaller than that of the plate-like ceramic body.
[0030]
The contact member may have a circular cross section.
[0031]
The contact member has a cross-sectional diameter of 1 mm or less.
[0032]
The resistance heating element includes an arc-shaped pattern in contact with the circumscribed circle and a connection pattern continuously connected to the arc-shaped pattern, and a blank area without the arc-shaped pattern is part of the circumscribed circle. It exists, The space | interval of this blank area is smaller than the difference of the diameter of the said plate-shaped ceramic body, and the diameter of the said circumscribed circle, It is characterized by the above-mentioned.
[0033]
The line width of the arc-shaped pattern is equal to or larger than the line width of the connection pattern connected to the arc-shaped pattern.
[0034]
Further, the thickness of the plate-shaped ceramic body is 1 to 7 mm, the thickness of the resistance heating element is 5 to 70 μm, and the ratio of the area of the resistance heating element to the area of the circumscribed circle of the resistance heating element is 5 to 50 %.
[0035]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below.
[0036]
FIG. 1A is a cross-sectional view showing an example of a wafer support member 1 according to the present invention, and FIG. 1B is a schematic diagram showing that the plate-like ceramic body 2 of FIG. 1A has a convex shape. FIG. One main surface of the plate-like ceramic body 2 made of ceramics mainly composed of silicon carbide or aluminum nitride is used as a mounting surface 3 on which the wafer W is placed, and a resistance heating element 5 is formed on the other main surface, A heater plate 100 having a power feeding unit 6 electrically connected to the resistance heating element 5 is provided, and a power feeding terminal 11 is connected to the power feeding 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.
[0037]
Further, the wafer lift pins 25 can move the wafer W up and down through a hole penetrating the plate-like ceramic 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.
[0038]
Note that the wafer W is held in a state of being lifted from the mounting surface 3 by the wafer support pins 8, thereby preventing temperature variations due to contact of the wafer W or the like. 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.
[0039]
FIG. 2 is a cross-sectional view showing another embodiment of the wafer support member 1 according to the present invention. Unlike FIG. 1, the wafer support member 1 is fixed to the outer peripheral surface 13 of the plate-like ceramic body 2 via a connecting member 17 with a metal case. .
[0040]
FIG. 3 shows an example of the pattern shape of the resistance heating element 5, and the peripheral portion of the resistance heating element 5 is composed of concentric arc-shaped patterns 5 a and connection patterns 5 b continuously connected to these. The resistance heating element 5 located on the outer peripheral portion of the body 2 preferably has a concentric arc-shaped pattern 5a, and any pattern shape can be used as long as the mounting surface 3 can be heated uniformly. Further, in order to improve the thermal uniformity, the resistance heating element 5 is divided into a total of six patterns, four in the peripheral part and two in the central part. Moreover, the line width and density of the pattern may be adjusted to improve the heat uniformity by providing a distribution of the calorific value density. In order to reduce the temperature difference in the wafer W, it is preferable that the diameter DC of the circumscribed circle C of the resistance heating element 5 is equal to the diameter DW of the wafer W or larger than the diameter DW.
[0041]
FIG. 4 shows another example of the pattern shape of the resistance heating element 5 of the present invention. The resistance heating element 5 shows an example in which the resistance heating element 5 is divided into a total of five patterns, four at the periphery and one at the center.
[0042]
FIG. 5 shows another example in which the resistance heating element 5 has a single pattern shape.
[0043]
In the wafer support member 1 of the present invention, the mounting surface 3 for placing the wafer W on one main surface of the plate-like ceramic body 2 is convex, and the diameter DC of the circumscribed circle C of the resistance heating element 5 is the plate-like shape. It is important that it is 90 to 99% of the diameter D of the ceramic body 2.
[0044]
When the mounting surface 3 is convex, it is preferable to place the wafer W cooled to room temperature on the heated plate-like ceramic body 2 because the temperature difference in the wafer W surface is heated in a small state.
[0045]
Further, if the diameter DC of the circumscribed circle C of the resistance heating element 5 is 90 to 99% of the diameter D of the plate-like ceramic body 2, a synergistic effect due to the convexity of the mounting surface 3 is expressed, and the wafer W is formed. The temperature difference in the wafer W surface from the moment when it is placed on the mounting surface 3 until the wafer W is heated and reaches a certain temperature is reduced. As a result, it has been found that, for example, the in-plane uniformity of the resist film on the wafer W is extremely excellent.
[0046]
When the mounting surface 3 is convex and the diameter DC of the circumscribed circle C of the resistance heating element 5 is smaller than 90% of the diameter D of the plate-like ceramic body 2, the instantaneous plate-like ceramic on which the wafer W is placed on the plate-like ceramic body 2 Although the heat of the body 2 is deprived, the temperature of the periphery of the plate-shaped ceramic body 2 is set while being heated at a higher temperature than the center of the wafer W because the temperature decrease is small because the wafer W is not opposed. Converge on temperature. For this reason, there is a possibility that the temperature difference at the time of transition in the wafer W surface becomes large. In addition, the time for rapidly raising or lowering the temperature of the wafer is increased, and the temperature response characteristics of the wafer W are inferior. Furthermore, the diameter D of the plate-like ceramic body 2 is increased, and the size of the wafer W that can be uniformly heated is smaller than the diameter D of the plate-like ceramic body 2, and the wafer heating efficiency with respect to the electric power for heating the wafer W is improved. Deteriorate.
[0047]
When the mounting surface 3 is convex and the diameter DC of the circumscribed circle C of the resistance heating element 5 is larger than 99% of the diameter D 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. Since a large amount of heat flows from the outer peripheral portion of the heating element 5 to the contact member 17 and the heat capacity of the peripheral portion of the plate-like ceramic body 2 that does not face the wafer W is small, the moment when the wafer W is placed on the plate-like ceramic body 2, There is a possibility that the temperature around the wafer W is too low and the wafer W is heated with a large temperature difference in the surface.
[0048]
Further, when the wafer W temperature is in a steady state, heat flows from a portion where the arc-shaped pattern 5 a on the outer peripheral portion does not exist, and the arc-shaped pattern 5 a on the outer peripheral portion is bent toward the center of the plate-like ceramic body 2. This is because the temperature of the portion P where the arc-shaped pattern 5a is missing along the circumscribed circle C surrounding the resistance heating element 5 is lowered, and the in-plane temperature difference of the wafer W may be increased.
[0049]
More preferably, the diameter DC of the circumscribed circle C of the resistance heating element 5 is 92 to 97% of the diameter D of the plate-like ceramic body 2.
[0050]
In particular, in the case of the wafer support member 1 in FIG. 1 in which the outer shapes of the plate-like ceramic body 2 and the metal case 19 are substantially equal and the metal case 19 supports the plate-like 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 DC of the circumscribed circle C of the resistance heating element 5 is 92 to 95%, more preferably 93 to 95% of the diameter D of the plate-like ceramic body 2.
[0051]
On the other hand, in the case of the wafer support member of FIG. 2 in which the metal case 19 is connected so as to cover the outer peripheral surface 13 of the plate-like ceramic body 2, the diameter DC of the circumscribed circle C of the resistance heating element 5 is that of the plate-like ceramic body 2. The diameter D is preferably 95 to 98%, more preferably 96 to 97%.
[0052]
The wafer support member 1 of the present invention has been described with an example in which the metal case 19 is connected to the lower surface of the peripheral portion of the plate-like ceramic body 2 or the metal case is connected to the outer peripheral surface 13 of the plate-like ceramic body 2. Of course, the wafer supporting member 1 connected to the metal case 19 at the same time on both the lower surface and the outer peripheral surface is also included.
[0053]
Moreover, it is preferable that the protrusion amount to of the convex mounting surface 3 is 5 to 90 μm.
[0054]
If the protruding amount is less than 5 μm or the mounting surface 3 is concave, the distance from the peripheral portion to the plate-like ceramic body 2 at the center of the wafer W becomes larger, and the heat transfer from the mounting surface 3 is slow. Therefore, there is a possibility that the temperature of the central portion of the wafer W at the time of transition immediately after the wafer W is placed on the placement surface 3 is lowered.
[0055]
If the protrusion amount exceeds 90 μm, the difference in height between the central portion and the peripheral portion of the plate-like ceramic body 2 becomes too large, and the distance between the peripheral portion of the wafer W and the plate-like ceramic body 2 is larger than that of the central portion. This is because the temperature of the peripheral part is lower than that of the central part, and there is a risk of heating with a large temperature difference.
[0056]
More preferably, the protruding amount of the convex mounting surface 3 is 20 to 70 μm, and more preferably 30 to 50 μm. This protrusion amount is also related to the size of the wafer W, and it has been found that the effect becomes larger when the wafer W has a diameter of approximately 300 mm or more.
[0057]
FIG. 6 is an enlarged cross-sectional view showing the vicinity of the ring-shaped contact member 17 of the wafer support member 1 shown in FIG. 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 amount of heat that flows from the plate-like ceramic body 2 to the bottomed metal case 19 via the contact member 17 can be reduced. Smaller is preferable. Further, the temperature difference in the normal state in the surface of the wafer W is small, and the wafer W can be heated uniformly.
[0058]
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 cooled to room temperature. At the moment when the wafer is placed on the mounting surface 3, the temperature around the wafer W is heated low, and it becomes difficult to uniformly heat the wafer W. 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.
[0059]
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 of the wafer is raised or lowered, the amount of heat transferred to the contact member 17 is small and the thermal interference with the bottomed metal case 19 is small, and the temperature difference in the wafer W surface during the transition is small and quickly. It becomes easy to change the temperature.
[0060]
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, the heat of the plate-like ceramic body 2 flows to the bottomed metal case 19 via the contact member 17. It is difficult, and the effect that the heat shrinkage of the metal case 19 adversely affects the temperature difference in the wafer W surface immediately after the wafer W is placed on the plate-like ceramic body 2 is preferable.
[0061]
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.
[0062]
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-like ceramic body 2 can be held with high accuracy without being displaced or changing in parallelism.
[0063]
In addition, the precision which cannot be obtained with the contact member which consists of resin which added resin and glass fiber to the fluorine-type contact member can be achieved.
[0064]
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.
[0065]
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 preferable that the surface temperature of the wafer W can be uniformly raised and lowered quickly without changing the position of the wafer W, and that the in-plane temperature difference during the transition of the wafer W can be reduced.
[0066]
Further, the wafer support member 1 of the present invention includes an arc-shaped pattern 5a in contact with the circumscribed circle C of the resistance heating element 5 and a connection pattern 5b continuously connected to the arc-shaped pattern. There is a blank area P without the arc-shaped pattern in the part, and the interval S between the blank areas P is the difference between the diameter D of the plate-like ceramic body and the diameter DC of the circumscribed circle C (hereinafter abbreviated as L). Smaller). In particular, it has been found that it is preferable to reduce the temperature difference in the wafer W surface immediately after the wafer W is placed on the placement surface 3.
[0067]
If the distance S is larger than L, the heat of the blank area P flows to the peripheral part of the plate-shaped ceramic body, and the temperature of the blank area P may be lowered. However, if the interval S is smaller than L, the temperature of the blank area P is unlikely to decrease, and the temperature in the peripheral portion of the wafer W placed on the mounting surface 3 of the plate-like ceramic body 2 does not decrease, but the temperature within the wafer W surface. This is preferable because the difference is reduced.
[0068]
Therefore, it is preferable that the line width of the arc-shaped pattern is equal to or larger than the line width of the connection pattern connected to the arc-shaped pattern.
[0069]
In order not to lower the temperature of the blank area P, it is necessary to raise the temperature of the blank area. If the resistance of the connection pattern 5b for heating the blank area is equal or increased to increase the heat generation amount, The possibility that the temperature is lowered is reduced, and the in-plane temperature of the wafer W is preferably uniform. When the resistance heating element 5 created by printing or the like has a planar cross section, the resistance of the connection pattern 5b can be increased by making the line width Ws of the connection pattern 5b smaller than the line width Wp of the arc-shaped pattern 5a. The in-plane temperature of the wafer W can be made uniform by raising the temperature of the connection pattern 5b above the temperature of the arc-shaped pattern 5a.
[0070]
The plate-like ceramic body 2 has a thickness of 1 to 7 mm, the resistance heating element 5 has a thickness of 5 to 70 μm, and occupies the circumscribed circle C with respect to the area of the circumscribed circle C surrounding the resistance heating element. The area ratio of the resistance heating element 5 is preferably 5 to 50%.
[0071]
That is, if the ratio of the area of the resistance heating element 5 to the area of the circumscribed circle C surrounding the resistance heating element 5 is less than 5%, the opposing interval S1 between the opposing areas in the opposing area of the resistance heating element 5 is as follows. Since it 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 it is difficult to make the temperature of the mounting surface 3 uniform.
[0072]
On the contrary, when 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%, it is between the plate-like ceramic body 2 and the resistance heating element 5. Of thermal expansion of 3.0 × 10 -6 Even when approximated to / ° C. or less, the thermal stress acting between the two is too large, and the plate-like ceramic body 2 is made of a ceramic sintered body that is difficult to deform, but the thickness t of the plate-like ceramic body 2 is When the resistance heating element 5 is heated because it is as thin as 1 mm to 7 mm, the plate-like ceramic body 2 is warped so that the mounting surface 3 side is concave, and as a result, the temperature of the central portion of the wafer W is higher than the peripheral edge. There is a risk that the temperature variation also becomes large and the temperature variation becomes large.
[0073]
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.
[0074]
More specifically, the resistance heating element 5 has a counter area that opposes the outer peripheral portion, and the interval S1 between the counter areas is 0.5 mm or more, and is not more than three times the plate thickness of the plate-like ceramic body 2. Preferably there is. If the interval S1 between the opposing regions is 0.5 mm or less, when the resistance heating element 5 is printed and formed, whisker-like protrusions may occur in the opposing region of the resistance heating element 5 and the portion may be short-circuited. Further, when the interval S1 between the opposing regions exceeds three times the thickness of the plate-like ceramic body 2, a cool zone is generated on the surface of the wafer W corresponding to the opposing region S1, and the in-plane temperature difference of the wafer W may be increased. Because there is.
[0075]
Furthermore, in order to efficiently exhibit such an effect, the thickness of the resistance heating element 5 is preferably set to 5 to 70 μm.
[0076]
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 70 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 increased, the rigidity of the resistance heating element 5 is increased, and the temperature change of the plate-like ceramic body 5 Therefore, the plate-like ceramic body 2 may be deformed due to the influence of the expansion and contraction of the resistance heating element 5. In addition, it is difficult to print to 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.
[0077]
Next, another detailed configuration and manufacturing method will be described.
[0078]
The thickness t of the plate-like ceramic body 2 of the wafer support member 1 according to the present invention is preferably 1 to 7 mm, and is composed of the plate-like ceramic body 2 having a Young's modulus of 100 to 200 ° C. of 200 to 450 MPa.
[0079]
Silicon carbide, alumina, silicon nitride, sialon, and aluminum nitride can be used as the material of the plate-like ceramic body 2 whose Young's modulus at 100 to 200 ° C. is 200 to 450 MPa. Among these, aluminum nitride is particularly 50 W / ( It has a high thermal conductivity of at least 100W / (m · K) and is excellent in corrosion resistance and plasma resistance to corrosive gases such as fluorine and chlorine. It is suitable as a material for the ceramic 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 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 temperature measuring element 27 for measuring the temperature of the plate-like ceramic body 2 are provided.
[0082]
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.
[0083]
The plate-shaped 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 so that the plate-shaped ceramic body 2 and the bottomed metal case 19 do not directly contact each other. And the nut 20 is screwed together with the elastic body 18 interposed from the bottomed metal case 19 side 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.
[0084]
Further, in order to form the mounting surface so as to be convex, the heater plate 100 in which the resistance heating element 5 is formed on the plate-shaped ceramic is fixed to the metal case 19 via the contact member 17, and then the conduction terminal 11 is formed. It can be adjusted by the pressing force. In order to enable rapid temperature rise and fall, the thickness of the heater plate 100 is adjusted to a range of 1 to 7 mm. On the other hand, the outer shape of the heater plate 100 increases with the increase in size of the wafer W from 200 mm to 300 mm. The diameter tends to increase from 230 mm to 330 mm. Due to the increase in area and thickness of the heater plate 100, the heater plate 100 is deformed by the pressing force of the conduction terminal 11.
[0085]
Therefore, the protruding amount of the heater plate 100 can be adjusted using this pressing force. In some cases, after processing the heater plate 100 so that the mounting surface 3 side is flat or concave, the heater plate 100 can be formed into a convex shape with a target of 5 to 90 μm by the pressing force of the conduction terminal 11. .
[0086]
Further, on the mounting surface 3 side of the heater plate 100, 0.8 to 1.8 × 10 6 from the thermal expansion coefficient of the heater plate 100. -6 By forming a glass layer having a large thermal expansion coefficient at 40 ° C./300 μm in thickness, warpage such that the mounting surface 3 side is convex may be generated.
[0087]
When the thickness of the glass layer is less than 40 μm, the influence on the warp is reduced, and thus a desired effect cannot be expected. On the other hand, if the thickness of the glass layer exceeds 300 μm, heat transfer from the mounting surface 3 side is slow, and the temperature rise rate of the wafer W is slow, which is not preferable.
[0088]
Next, the manufacturing method and configuration of the wafer support member 1 when the wafer support member 1 is used for forming a resist film will be described.
[0089]
If silicon carbide is used as the main component of the plate-like ceramic body 2, it does not react with moisture in the atmosphere and does not generate gas, so even if it is used for attaching the resist film on the wafer W, the resist film Fine wirings can be formed at high density without adversely affecting the tissue. At this time, it is necessary that the sintering aid does not contain nitrides that may react with water to form ammonia or amines.
[0090]
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 3 ) Yttria (Y 2 O 3 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.
[0091]
When a 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. In the case of using glass, if the thickness is less than 100 μm, the withstand voltage is less than 1.5 kV and insulation cannot be maintained. Conversely, if the thickness exceeds 400 μm, silicon carbide forming the plate-like ceramic body 2 Since the difference in thermal expansion from the sintered material becomes too large, cracks occur and the insulating layer does not function. Therefore, when glass is used as the insulating layer, the thickness of the insulating layer is preferably formed in the range of 100 to 400 μm, and desirably in the range of 200 μm to 350 μm.
[0092]
Furthermore, the main surface opposite to the mounting surface 3 of the plate-like ceramic body 2 has a flatness of 20 μm or less and a surface roughness with a center line average roughness from the viewpoint of improving the adhesion with an insulating layer made of glass or resin. It is preferable that (Ra) be polished to 0.1 μm to 0.5 μm.
[0093]
On the other hand, when the plate-like ceramic body 2 is formed of a sintered body containing aluminum nitride as a main component, Y is used as a sintering aid for the main component aluminum nitride. 2 O 3 And Yb 2 O 3 It is obtained by adding rare earth element oxides such as CaO and alkaline earth metal oxides such as CaO as necessary and mixing them well, processing them into a flat plate, and then firing them in nitrogen gas at 1900-2100 ° C. 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 to the resistance heating element 5 and sufficient adhesion strength is obtained by this, it can be omitted.
[0094]
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. + 1 × 10 for the thermal expansion coefficient of the ceramics -7 / ° C to + 6 × 10 -7 It is preferable to select and use a large 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. This is because the mounting surface 3 side is easily formed in a convex shape.
[0095]
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. Further, 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., and the insulating layer is deposited. By subjecting to an oxidation treatment, it is possible to improve the adhesion to the insulating layer made of glass.
[0096]
As shown in FIG. 9, the resistance heating element pattern in which the closely spaced portions and the rough portions of the resistance heating elements 25 appear alternately in the radial direction from the center of the plate-like ceramic body 22 corresponds to the rough portions. This is not preferable because the surface temperature of the wafer W is small, the temperature of the wafer W corresponding to the dense portion is large, and it is difficult to uniformly heat the entire surface of the wafer W.
[0097]
The resistance heating element 5 is obtained by printing and baking an electrode paste containing glass frit or metal oxide on conductive metal particles on the plate-like ceramic body 2 by a printing method. As the metal particles, Au, Ag, Cu, It is preferable to use at least one metal of Pd, Pt, and Rh, and the glass frit is made of an oxide containing B, Si, and Zn, and is 4.5 × 10 4 smaller than the thermal expansion coefficient of the plate-like ceramic body 2. -6 It is preferable to use low-expansion glass at / ° C. or less, and it is preferable to use at least one selected from silicon oxide, boron oxide, alumina, and titania as the metal oxide.
[0098]
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.
[0099]
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 larger than the thermal expansion coefficient of the plate-like ceramic body 2. In order to make the thermal expansion coefficient of the resistance heating element 5 close to the thermal expansion coefficient of the plate-like ceramic body 2, 4.5 × 10 larger than the thermal expansion coefficient of the plate-like ceramic body 2. -6 This is because it is preferable to use a low expansion glass at / ° C. or lower.
[0100]
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, In addition, the thermal expansion coefficient is close to the thermal expansion coefficient of the plate-like ceramic body 2 and the adhesiveness with the plate-like ceramic body 2 is also excellent.
[0101]
However, if the content of the metal oxide exceeds 80% with respect to the resistance heating element 5, the adhesion with the plate-like ceramic body 2 is increased, but the resistance value of the resistance heating element 5 is not preferable. Therefore, the content of the metal oxide is preferably 60% or less.
[0102]
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. Thermal expansion difference is 3.0 × 10 -6 If the temperature exceeds / ° C., when the resistance heating element 5 is heated, the mounting surface 3 side may be warped in a concave shape due to thermal stress acting between the plate-like ceramic body 2.
[0103]
Further, as the resistance heating element 5 material deposited on the insulating layer, a simple metal such as gold (Au), silver (Ag), copper (Cu), palladium (Pd) or the like is directly applied by a vapor deposition method or a plating method. The metal alone or rhenium oxide (Re 2 O 3 ), Lanthanum manganate (LaMnO) 3 ) And other conductive metal oxides or a paste in which the above metal material is dispersed in a resin paste or glass paste, printed in a predetermined pattern shape by screen printing or the like, and baked to obtain the conductive material. What is necessary is just to combine with the matrix which consists of resin or glass. When glass is used as the matrix, either crystallized glass or amorphous glass may be used, but crystallized glass is preferably used in order to suppress a change in resistance value due to thermal cycling.
[0104]
However, when silver (Ag) or copper (Cu) is used for the resistance heating element 5 material, migration may occur. In such a case, the same as the insulating layer is provided so as to cover the resistance heating element 5. What is necessary is just to coat | coat the coating layer which consists of material with the thickness of about 40-400 micrometers.
[0105]
Further, regarding a method of feeding power to the resistance heating element 5, a feeding part 6 made of a material such as gold, silver, palladium, or platinum is formed on the resistance heating element 5, and a feeding terminal 11 is brought into contact with the feeding part 6. , Conduction is ensured. As long as the power supply terminal 11 and the power supply section 6 can secure continuity, a technique such as soldering or brazing may be used. However, the power supply terminal 11 installed on the bottomed metal case 19 is plate-shaped. It is preferable to place the mounting surface 3 in a convex shape by pressing the power supply portion 6 formed on the surface of the ceramic body 2 with a spring (not shown), to secure the connection and to supply power. This is because when the terminal portion made of metal is embedded in the plate-like ceramic body 2 having a thickness of 1 to 7 mm, the thermal uniformity is deteriorated due to the heat capacity of the terminal portion. Therefore, by pressing the power supply terminal 11 with a spring to ensure electrical connection, the thermal stress due to the temperature difference between the plate-like ceramic body 2 and the bottomed metal case 19 is alleviated, and the electricity is highly reliable. Continuity can be maintained. 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.
[0106]
The temperature of the plate-like ceramic body 2 is measured by a temperature measuring element 27 such as a thermocouple in which the tip is embedded in the plate-like ceramic body 2. As the temperature measuring element 27, it is preferable to use a sheath-type thermocouple having an outer diameter of 0.8 mm or less from the viewpoint of its responsiveness and workability of holding. In order to improve the reliability of temperature measurement, it is preferable that the tip of the thermocouple has a hole formed in the plate-like 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.
[0107]
Further, although the wafer support member 1 having only the resistance heating element 5 on the other main surface 3 of the plate-like ceramic body 2 has been shown, the present invention provides an electrostatic adsorption between the main surface 3 and the resistance heating element 5. Needless to say, the electrodes may be embedded for use in plasma generation.
[0108]
【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.
[0109]
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.
[0110]
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.
[0111]
A laminate was formed by laminating a plurality of obtained aluminum nitride green sheets.
[0112]
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.
[0113]
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 315 mm to 345 mm, and further penetrates three places evenly on a concentric circle of 60 mm from the center. A hole was formed. The through-hole diameter was 4 mm.
[0114]
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 seven pattern configurations consisting of four patterns were formed on the outer side. 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. Then, a coating layer was formed so as to cover the resistance heating element, and then the feeding part 6 was brazed and fixed to the resistance heating element 5 to manufacture the plate-like ceramic body 2.
[0115]
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.
[0116]
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.
[0117]
In addition, the protrusion amount of the convex mounting surface was adjusted by changing the force pressing the plate-like ceramic body with the conduction terminal and the thickness of the coating layer.
[0118]
In addition, a wafer support member was manufactured with two structures, a support structure (1) for supporting the lower surface of the peripheral portion of the plate-shaped ceramic body and a support structure (2) for supporting the outer peripheral surface of the plate-shaped ceramic body. In the support structure (1), the diameter of the plate-like ceramic body is the same as the diameter of the metal case.
[0119]
The contact member was ring-shaped and the cross section was rectangular. The trapezoidal cross section had a thickness of 1 mm and a width of 5 mm. Further, Ti or titanium alloy was used as the material of the contact member. The prepared various wafer support members are sample Nos. 1-12.
[0120]
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. It was kept until it became constant within the range. Thereafter, the wafer W was removed. Then, using the temperature measuring wafer W, a wafer W having the same room temperature as the wafer W was placed on the mounting surface, and the temperature of each resistance temperature detector until the temperature of the wafer W reached 200 ° C. was measured. Then, the time from room temperature 25 ° C. to 200 ° C. ± 0.5 ° C. is measured as the response time, and the maximum temperature difference of each resistance thermometer until then until the wafer reaches 200 ° C. at the time of transition. The maximum temperature difference (° C.) within the wafer surface was taken.
[0121]
Further, after the temperature cycle of 30 ° C. to 200 ° C. in 5 minutes and holding for 5 minutes and then cooling for 30 minutes is repeated 1000 cycles, the temperature is set from room temperature to 200 ° C. and the maximum value of the wafer temperature after 10 minutes The difference between the minimum values was measured as the temperature difference of the wafer W.
[0122]
Each result is as shown in Table 1.
[0123]
[Table 1]
Figure 2005050834
[0124]
Sample No. in Table 1 No. 1 is that the ratio of the circumscribed circle of the resistance heating element to the diameter of the plate-shaped ceramic body is 90%, but since the mounting surface is a concave shape of −10 μm, the maximum temperature difference in the wafer W surface at the time of transition is The temperature difference of the wafer was as large as 11.5 ° C. and the temperature difference of the wafer was as large as 0.5 ° C., and the response time was particularly large as 65 seconds.
[0125]
Sample No. No. 12 was not preferable because the ratio of the circumscribed circle of the resistance heating element to the diameter of the plate-like ceramic body was 99.5%, the in-plane temperature difference of the wafer was as large as 2.1 ° C., and the response time was as large as 68 seconds.
[0126]
On the other hand, in the case of sample No. 1 in which the mounting surface is convex and the diameter of the circumscribed circle of the resistance heating element is 90 to 99% of the diameter of the plate-like ceramic body. 3 to 11 show that the temperature difference in the plane of the wafer is as small as less than 0.5 ° C., and the response time is as small as 38 seconds or less.
[0127]
Furthermore, in the support structure {circle around (1)} connected to the metal case via the contact member on the lower surface of the outer peripheral portion of the plate-like ceramic body, As shown in 4 to 6, the ratio of the circumscribed circle of the resistance heating element to the diameter of the plate-like ceramic body is 92 to 95%, the maximum temperature difference in the wafer surface is as small as 5.5 ° C. or less, and the in-plane temperature of the wafer The difference is excellent at 0.40 ° C. or less and the response time is 34 seconds or less.
[0128]
Sample No. Nos. 5 and 6 have an in-plane temperature difference of 0.35 ° C. or less and a response time of 33 seconds or less, so that the ratio of the circumscribed circle of the resistance heating element to the diameter of the plate-like ceramic body is 93 to 95%. It turns out that it is preferable.
[0129]
On the other hand, in the supporting structure (2) connected to the metal case and the contact member on the outer peripheral side surface of the plate-shaped ceramic body, As shown in 7 to 10, the ratio of the circumscribed circle of the resistance heating element to the diameter of the plate-like ceramic body is 95% to 98%, the in-plane temperature difference of the wafer is 0.44 ° C. or less, and the response time is 33 seconds or less. And was excellent. Furthermore, sample no. Since the in-plane temperature difference between 8 and 9 is both 0.40 ° C. and the response time is as short as 30 seconds, the ratio of the circumscribed circle of the resistance heating element to the diameter of the plate-like ceramic body is 96% to 97%. Has been found to be more preferable.
[0130]
Further, the amount of protrusion of the mounting surface is the sample No. It turned out that it is preferable in it being 5 micrometers to 90 micrometers like 3-11.
[0131]
(Example 2)
A plate-like ceramic body 2 was produced in the same manner as in Example 1.
[0132]
The bottomed metal case 19 is made of aluminum having a diameter of 330 mm and a thickness of 2.0 mm forming the bottom surface 21 and a thickness of 1.0 mm forming the side wall portion 22. The pair 13 and the conduction terminal 11 were attached at predetermined positions. The distance from the bottom surface 21 to the plate-like ceramic body 2 was 20 mm. Thereafter, the plate-like ceramic body 2 is overlaid on the opening of the bottomed metal case 19, and the bolt 16 is passed through the outer periphery thereof so that the plate-like ceramic body 2 and the bottomed metal case 19 do not directly contact each other. The wafer support member 1 was elastically fixed by interposing the ring-shaped contact member 17 and screwing the nut 20 through the elastic member 18 from the contact member 17 side. The cross section of the contact member 17 is trapezoidal, and has a ring shape that supports the periphery of the plate-like ceramic body. The size of the trapezoidal cross section is 4 mm for the lower side and 2 mm for the upper side, 0.05 to 4 mm for the upper side, 15 mm for the lower side, 2 mm for the height, and 5 to 15 mm for the upper side for each wafer support member. Attached. The contact member was made of titanium. The prepared various wafer support members are sample Nos. 21 to 29.
[0133]
The protruding amount of the mounting surface 3 was constant at 40 μm, and the diameter of the circumscribed circle of the resistance heating element 5 was 95% of the diameter of the plate-like ceramic body 2.
[0134]
Evaluation was performed in the same manner as in Example 1.
[0135]
Each result is as shown in Table 2.
[0136]
[Table 2]
Figure 2005050834
[0137]
As can be seen from Table 1, sample no. In No. 21, the width of the contact portion between the contact member 17 and the plate-like ceramic body 2 was as small as 0.05 mm, and the response time and the temperature difference of the wafer were small. However, the maximum temperature difference in the wafer surface was slightly large at 5.6 ° C., which was not preferable.
[0138]
Sample No. In No. 29, the width of the contact portion of the contact member 17 was as large as 15 mm, and the maximum temperature difference in the wafer surface was slightly large at 6 ° C.
[0139]
In contrast, sample no. The wafer support members 1 to 22 to 28 have an area where the contact member 17 is in contact with the plate-like ceramic body 2 and is 0.1 to 13 mm. Therefore, the maximum temperature difference in the wafer surface is as small as 4.1 ° C. or less. The in-plane temperature difference was 0.4 ° C. or less, and the response time was as small as 38 seconds or less.
[0140]
(Example 3)
In the same manufacturing process of the plate-like ceramic body 2 as in Example 1, the plate-like ceramic body 2 was produced by changing the amount of yttrium oxide added in the range of 0.1 to 5% by mass. Moreover, the contact member whose width of the contact part which contacts the plate-shaped ceramic body 2 was 2 mm was produced using SUS304, SUS403, Fe-Ni-Co alloy (Kovar), carbon steel, and aluminum. Then, the plate-like ceramic body and the contact member are combined so that the ratio of the thermal conductivity of the plate-like ceramic body 2 to the thermal conductivity of the contact member is 1 to 128%, and the plate-like ceramic body is made of aluminum via the contact member. A wafer support member was prepared by attaching a metal case with a bottom.
[0141]
Sample No. 31 to 38 used metal contact members. The bottomed metal case had a diameter of 330 mm, a side wall thickness of 1.0 mm, a bottom thickness of 2.0 mm, and a depth of 30 mm. Sample No. 39 and 40 are resin contact members whose Young's modulus is less than 1 GPa, so that the deformation of the trapezoidal contact member is large and difficult to use as a wafer support member. Therefore, as shown in FIG. The bottomed metal case had a diameter of 340 mm, a side wall thickness of 1.0 mm, a bottom surface thickness of 2.0 mm, and a depth of 30 mm.
[0142]
And it evaluated similarly to Example 1. FIG.
[0143]
The results are shown in Table 3.
[0144]
[Table 3]
Figure 2005050834
[0145]
Sample No. SUS304, Fe—Ni—Co alloy, SUS403, carbon steel was used as the contact member, combined with aluminum nitride having a different thermal conductivity, and the thermal conductivity of the contact member was smaller than the thermal conductivity of the plate-like ceramic body. It was found that the wafer contact members 31 to 37 were excellent with a response time within 35 seconds and a wafer temperature difference of 0.35 ° C. or less.
[0146]
However, sample no. No. 38 has a thermal conductivity of the contact member larger than that of the plate-like ceramic body, the maximum temperature difference in the wafer surface is as large as 5.7 ° C., the response time is slightly large as 53 seconds, and the temperature difference in the wafer surface is 0. It was somewhat large at 55 ° C.
[0147]
Therefore, it has been found that the wafer support member whose thermal conductivity of the contact member is smaller than that of the plate-like ceramic body exhibits excellent characteristics with small response characteristics and temperature difference of the wafer.
[0148]
(Example 4)
A plate-like ceramic body was produced in the same manner as in Example 2. Also, the width of the contact portion of the contact member that contacts the plate-like ceramic body using SUS304, SUS403, Fe-Ni-Co alloy (Kovar), carbon steel, aluminum, tin, tin-lead alloy is 0.1 mm, and Young's modulus Different contact members were produced. Then, a bottomed metal case made of aluminum was attached to the plate-like ceramic body through the contact member in the same manner as in Example 2 to produce a wafer support member.
[0149]
And it evaluated similarly to Example 1. FIG.
[0150]
The results are shown in Table 4.
[0151]
[Table 4]
Figure 2005050834
[0152]
Sample No. made of a contact member having a Young's modulus of 1 GPa or more. The wafer support members Nos. 41 to 47 have preferable characteristics such that the maximum temperature difference of the wafer is 4.3 ° C. or less, the temperature difference in the wafer surface is 0.35 ° C. or less, and the response time is 35 seconds or less. I found out.
[0153]
However, sample no. The wafer support member made of 48 fluororesins or fiber-filled resins had a maximum wafer temperature difference of 6 ° C., a wafer surface temperature difference of 0.49 ° C., and a response time of 45 seconds.
[0154]
Therefore, it was found that the Young's modulus of the contact member is 1 GPa or more and 300 GP or less.
[0155]
(Example 5)
A plate-like ceramic body was produced in the same manner as in Example 1. Also, a carbon steel steel trapezoidal wafer support member and a carbon steel contact member having a circular cross section are produced as contact members, and a bottom made of aluminum is formed on the plate-like ceramic body via the contact member. A metal support case was attached to produce a wafer support member.
[0156]
And it evaluated similarly to Example 1. FIG.
[0157]
The results are shown in Table 5.
[0158]
[Table 5]
Figure 2005050834
[0159]
Sample No. The wafer support member with the trapezoidal contact members 51 and 52 has a maximum temperature difference in the wafer surface of 4.5 ° C. and 3.2 ° C., and the temperature difference in the wafer surface is 0.36 ° C. and 0.26 ° C. Although the time was 35 seconds and 29 seconds, the sample No. having the structure shown in FIG. When the contact member has a circular cross-section like 53 and 54, the response time is as small as 23 seconds and 21 seconds, and the maximum temperature difference of the wafer is as small as 3.1 ° C. and 2.8 ° C. It has been found that the difference is as small as 0.25 ° C. and 0.22 ° C. and more preferable.
[0160]
In particular, a wafer support member having a circular cross section of the contact member and a cross section diameter of 1 mm or less has a response time of 21 seconds, a maximum wafer temperature difference of 2.8 ° C., and an in-plane temperature difference of 0.22 ° C. Further, it has been found that excellent characteristics are exhibited.
[0161]
(Example 6)
A plate-like ceramic body was produced in the same process as in Example 1. Then, a resistance heating element was printed on the main surface of the plate-like ceramic body in the same process as in Example 1. The pattern of the outermost resistance heating element is the configuration of the outermost pattern shown in FIG. 4, and the space S between the blank areas P having no arc-shaped pattern in a part of the circumscribed circle contacting the four outermost patterns as the resistance heating element. Then, a wafer support member was produced in which the diameter of the circumscribed circle in contact with the resistance heating element was 310 mm and the diameter of the plate-like ceramic body was changed.
[0162]
In addition, a bottomed metal case made of aluminum was attached to the plate-like ceramic body via the contact member to produce a wafer support member.
[0163]
And it evaluated similarly to Example 1. FIG. The results are shown in Table 6.
[0164]
[Table 6]
Figure 2005050834
[0165]
Sample No. in which the difference L between the diameter of the plate-shaped ceramic body and the diameter of the circumscribed circle of the resistance heating element is larger than the space S between the blank areas. 61, 65, and 67, the maximum temperature differences of the wafers are 5.5 ° C, 5.4 ° C, and 5.7 ° C, respectively, and the in-plane temperature differences of the wafers are 0.47 ° C, 0.45 ° C, and 0.48, respectively. The response time was slightly large at 38, 37 and 38 seconds.
[0166]
In contrast, sample no. The wafer support member in which the space S between the blank areas 62, 63, 64, 66 and 68 is smaller than the above difference L has a maximum wafer temperature difference of 3.3 ° C. or less, and the in-plane temperature difference of the wafer is 0.25. It was found that the temperature was as low as 0 ° C. or less, and the response was 29 seconds or less, indicating superior characteristics.
[0167]
(Example 7)
Sample No. 2 of Example 2 A wafer support member having the same configuration as that of No. 63 and having a line width of an arc-shaped pattern on the outer peripheral portion of the resistance heating element and a line width of a connection pattern connected thereto was produced and evaluated in the same manner as in Example 2. The results are shown in Table 3.
[0168]
[Table 7]
Figure 2005050834
[0169]
Sample No. with a connecting pattern line width equal to or larger than the arc-shaped pattern line width. The maximum temperature difference between wafers 73, 74, 76, and 77 is as small as 2.8 ° C or less, the in-plane temperature difference between the wafers is as small as 0.21 ° C or less, and the response time is 22 seconds or less. found.
[0170]
In addition, the sample No. 2 in which the line width of the connection pattern is smaller than the line width of the arc-shaped pattern. It was found that the maximum temperature difference between wafers 74 and 77 was as small as 2.5 ° C. and 2.69 ° C., the in-plane temperature difference was as small as 0.2 ° C., and the response time was extremely excellent at 20 seconds.
[0171]
In contrast, sample no. 71, 72, and 75 have a maximum wafer temperature difference of 5.1 to 5.3 ° C., a wafer surface temperature difference of 0.42 to 0.45 ° C., and a response time of 33 to 35 seconds. It was.
[0172]
Accordingly, in the wafer support member, the line width of the arc-shaped pattern is equal to or larger than the line width of the connection pattern connected to the arc-shaped pattern, so that an excellent wafer support member having a small wafer temperature difference and a small response time. It was found that can provide.
[0173]
(Example 8)
A plate-like ceramic body was produced in the same manner as in Example 1.
[0174]
However, the paste was printed at a thickness of 20 μm, and the ratio of the area occupied by the resistance heating element to the circumscribed circle surrounding the resistance heating element was prepared.
[0175]
And it evaluated similarly to Example 1. FIG. The results are shown in Table 8.
[0176]
[Table 8]
Figure 2005050834
[0177]
As a result, sample no. As shown in 80, the sample in which the ratio of the area occupied by the resistance heating element to the circumscribed circle surrounding the resistance heating element is less than 5% and 3%, the maximum temperature difference in the wafer surface is slightly 5.9 ° C. The wafer surface temperature difference was 0.48 ° C. and the response time was 39 seconds. Sample No. As in 89, if the ratio of the area occupied by the resistance heating element to the circumscribed circle surrounding the resistance heating element is more than 50% and 60%, a hot area having a high temperature appears in a part of the wafer, and the surface of the wafer The maximum temperature difference was 5.8 ° C., the in-plane temperature difference of the wafer was 0.45 ° C., and the response time was 34 seconds.
[0178]
In contrast, sample no. As shown in 81 to 88, the sample in which the ratio of the area occupied by the resistance heating element to the circumscribed circle of the resistance heating element is 5 to 50% has a maximum temperature difference in the plane of the wafer of 4.8 ° C. or less. The in-plane temperature difference of the wafer was as small as 0.39 ° C. or less, and the response time was as small as 34 seconds or less, indicating excellent characteristics.
[0179]
Sample No. Like 82-86, the ratio of the area which a resistance heating element occupies with respect to the circumscribed circle of a resistance heating element shall be 10-30%, and the maximum temperature difference in the surface of a wafer is less than 3.6 degreeC. It was found that the in-plane temperature difference of the wafer was as small as 0.28 or less and the response time was 29 seconds or less.
[0180]
Furthermore, sample no. Like 83-85, the ratio of the area which a resistance heating element occupies with respect to the circumscribed circle of a resistance heating element shall be 15-25%, and the maximum temperature difference in the surface of a wafer shall be less than 1.9 ° C, It was found that the in-plane temperature difference of the wafer was 0.17 ° C. or less and the response time was 22 seconds or less, which was extremely excellent.
[0181]
【The invention's effect】
As described above, according to the present invention, there is provided a wafer support member including a resistance heating element on one main surface of a plate-like ceramic body and a mounting surface on which the wafer is placed on the other main surface, A power supply section for supplying power to the heating element; and a metal case surrounding the power supply section, and the resistance heating element located on the outer periphery of the plate-shaped ceramic body has a concentric pattern, The surface is convex and the diameter of the circumscribed circle of the resistance heating element is 90 to 99% of the diameter of the plate-like ceramic body until the temperature immediately after the wafer is replaced on the plate-like ceramic body is stabilized. Thus, a wafer holding member having a small temperature variation in the wafer surface during the transition, a small temperature difference in the wafer surface and excellent temperature response characteristics can be obtained.
[0182]
Further, the wafer support member includes an arc-shaped pattern in contact with the circumscribed circle, and a connection pattern continuously connected to the arc-shaped pattern, and a blank area where the arc-shaped pattern is not part of the circumscribed circle Is smaller than the difference between the plate-shaped ceramic body and the diameter of the circumscribed circle, a wafer support member having high heat uniformity of the wafer can be obtained.
[Brief description of the drawings]
1A is a cross-sectional view showing an example of a wafer heating apparatus of the present invention, and FIG. 1B is a schematic view showing a plate-like ceramic body.
FIG. 2 is a cross-sectional view showing an example of another wafer heating apparatus of the present invention.
FIG. 3 is a schematic view showing the shape of the resistance heating element of the present invention.
FIG. 4 is a schematic view showing the shape of another resistance heating element of the present invention.
FIG. 5 is a schematic view showing the shape of another resistance heating element of the present invention.
FIG. 6 is a cross-sectional view showing an example of the wafer heating apparatus of the present invention, showing an enlarged view of the vicinity of the contact member.
FIG. 7 is a cross-sectional view showing an example of the wafer heating apparatus of the present invention, showing an enlarged view of the vicinity of the contact member.
FIG. 8 is a cross-sectional view showing an example of a conventional wafer heating apparatus.
FIG. 9 is a schematic view showing the shape of a conventional resistance heating element.
[Explanation of symbols]
1, 71: Wafer support member
2, 72: Plate-shaped ceramic body
3, 73: Placement surface
5, 75: Resistance heating element
6: Feeder
8: Support pin
10: Guide member
11, 77: Feeding terminal
13: Outer peripheral surface
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: Temperature measuring element
28: Conventional guide member
W: Semiconductor wafer

Claims (11)

板状セラミックス体の一方の主面に抵抗発熱体を備え、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、前記抵抗発熱体に電力を供給する給電部と、該給電部を囲む金属ケースとを有し、前記板状セラミックス体の外周部に位置する前記抵抗発熱体は同心円状のパターンを有し、上記載置面が凸状で、且つ前記抵抗発熱体の外接円の直径が前記板状セラミックス体の直径の９０〜９９％であることを特徴とするウェハ支持部材。A wafer support member provided with a resistance heating element on one main surface of the plate-shaped ceramic body, and a mounting surface on which the wafer is placed on the other main surface, a power supply unit for supplying power to the resistance heating element; A metal case surrounding the power supply portion, the resistance heating element located on the outer peripheral portion of the plate-shaped ceramic body has a concentric pattern, the mounting surface is convex, and the resistance heating element The diameter of the circumscribed circle is 90 to 99% of the diameter of the plate-like ceramic body. 前記凸状の載置面の突出量が５〜９０μｍであることを特徴とする請求項１に記載のウェハ支持部材。2. The wafer support member according to claim 1, wherein a protruding amount of the convex mounting surface is 5 to 90 μm. 前記板状セラミック体の周辺部をリング状に支持して前記金属ケースと接続する接触部材を備えていることを特徴とする請求項１または２に記載のウェハ支持部材。The wafer support member according to claim 1, further comprising a contact member that supports a peripheral portion of the plate-like ceramic body in a ring shape and is connected to the metal case. 前記接触部材が前記板状セラミックス体と接する巾が０．１〜１３ｍｍであることを特徴とする請求項１記載のウェハ支持部材。The wafer support member according to claim 1, wherein a width of the contact member in contact with the plate-like ceramic body is 0.1 to 13 mm. 前記接触部材の熱伝導率が前記板状セラミックス体の熱伝導率より小さいことを特徴とする請求項１または２に記載のウェハ支持部材。The wafer support member according to claim 1, wherein a thermal conductivity of the contact member is smaller than a thermal conductivity of the plate-like ceramic body. 前記接触部材のヤング率が１ＧＰａ以上で、板状セラミックス体のヤング率より小さいことを特徴とする請求項１〜３のいずれかに記載のウェハ支持部材。The wafer support member according to claim 1, wherein the contact member has a Young's modulus of 1 GPa or more and is smaller than the Young's modulus of the plate-like ceramic body. 前記接触部材の断面が円形状であることを特徴とする請求項１〜４のいずれかに記載のウェハ支持部材。The wafer support member according to claim 1, wherein a cross section of the contact member is circular. 前記接触部材の断面の直径が１ｍｍ以下であることを特徴とする請求項５記載のウェハ支持部材。6. The wafer support member according to claim 5, wherein a diameter of a cross section of the contact member is 1 mm or less. 前記抵抗発熱体は、前記外接円に接する円弧状パターンと、該円弧状パターンに連続して繋がった連結パターンとを備え、前記外接円の一部に前記円弧状パターンのない空白域が存在し、この空白域の間隔が、前記板状セラミックス体の直径と前記外接円の直径との差より小さいことを特徴とする請求項１〜８のいずれかに記載のウェハ支持部材。The resistance heating element includes an arc-shaped pattern in contact with the circumscribed circle and a connection pattern continuously connected to the arc-shaped pattern, and a blank area without the arc-shaped pattern exists in a part of the circumscribed circle. The wafer support member according to any one of claims 1 to 8, wherein an interval between the blank areas is smaller than a difference between a diameter of the plate-shaped ceramic body and a diameter of the circumscribed circle. 前記円弧状パターンの線幅は、前記円弧状パターンに繋がる前記連結パターンの線幅と同等或いは大きいことを特徴とする請求項１〜９のいずれかに記載のウェハ支持部材。10. The wafer support member according to claim 1, wherein a line width of the arc-shaped pattern is equal to or larger than a line width of the connection pattern connected to the arc-shaped pattern. 前記板状セラミックス体の厚みが１〜７ｍｍで、前記抵抗発熱体の厚みが５〜７０μｍであるとともに、前記抵抗発熱体の外接円の面積に対する抵抗発熱体の面積の比率が５〜５０％であることを特徴とする請求項１〜１０のいずれかに記載のウェハ支持部材。The thickness of the plate-shaped ceramic body is 1 to 7 mm, the thickness of the resistance heating element is 5 to 70 μm, and the ratio of the area of the resistance heating element to the area of the circumscribed circle of the resistance heating element is 5 to 50%. The wafer support member according to claim 1, wherein the wafer support member is provided.
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Publication number Priority date Publication date Assignee Title
JP2012503312A (en) * 2008-09-16 2012-02-02 エムイーエムシー・エレクトロニック・マテリアルズ・インコーポレイテッド Wafer holder to support semiconductor wafer during heat treatment process
JP2013102052A (en) * 2011-11-08 2013-05-23 Tokyo Ohka Kogyo Co Ltd Substrate processing apparatus and substrate processing method
JP7461121B2 (en) 2019-09-09 2024-04-03 株式会社クラベ Screen Heater System

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JP2012503312A (en) * 2008-09-16 2012-02-02 エムイーエムシー・エレクトロニック・マテリアルズ・インコーポレイテッド Wafer holder to support semiconductor wafer during heat treatment process
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JP7461121B2 (en) 2019-09-09 2024-04-03 株式会社クラベ Screen Heater System

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