JP3664193B2

JP3664193B2 - Heat treatment apparatus and heat treatment method

Info

Publication number: JP3664193B2
Application number: JP4795296A
Authority: JP
Inventors: 聡一菅野
Original assignee: Tokyo Electron Ltd
Current assignee: Tokyo Electron Ltd
Priority date: 1996-02-09
Filing date: 1996-02-09
Publication date: 2005-06-22
Anticipated expiration: 2016-02-09
Also published as: JPH09219435A

Description

【０００１】
【発明の属する技術分野】
本発明は、熱処理装置及び熱処理方法に関する。
【０００２】
【従来の技術】
半導体デバイスの製造プロセスにおいては、被処理体である半導体ウエハに酸化、拡散、ＣＶＤ（Chemical Vapor Deposition）、アニールなどの処理を行うために、各種の熱処理装置が使用されている。この種の熱処理装置の一つとして、被処理体を支持する支持部を有する移載機構により、上記被処理体を予め加熱された処理室内に水平方向から挿入移載して熱処理する枚葉式の熱処理装置が提案されている。
【０００３】
上記熱処理装置によれば、処理室内が予め加熱されているので、ウエハを迅速に昇温させて熱処理することが可能となり、スループットの向上が図れる。
【０００４】
【発明が解決しようとする課題】
しかしながら、上記熱処理装置においては、予め加熱された処理室内にウエハを挿入する際に、挿入方向の先端側と後端側とに生じる挿入時差により、ウエハには挿入方向に温度分布、すなわち面内温度差が発生する。この面内温度差が大きい場合には、ウエハにスリップ（結晶のズレ）が発生し、品質の低下や半導体デバイスの歩留りの低下を招く問題がある。
【０００５】
そこで、本発明は、上記課題を解決すべくなされたもので、被処理体を予め加熱された処理室内に水平方向から挿入する際の挿入時差による被処理体の面内温度差を可及的に低減し得る熱処理装置及び熱処理方法を提供することを目的とする。
【０００６】
【課題を解決するための手段】
上記目的を達成するために本発明のうち請求項１に係る発明は、被処理体を支持する支持部を有する移載機構により、上記被処理体を予め加熱された処理室内に水平方向から挿入移載して熱処理する熱処理装置において、上記支持部の熱容量または吸熱特性を、挿入時差による上記被処理体の面内温度差を低減すべく挿入方向に変化させてなることを特徴とする。
【０００７】
請求項２に係る発明は、請求項１に記載の熱処理装置における上記支持部が肉厚を挿入方向に漸増させて形成されていることを特徴とする。
【０００８】
請求項３に係る発明は、請求項１に記載の熱処理装置における上記支持部が上記被処理体とほぼ同じ平面形状に形成され、上面を上記被処理体の載置面とし、下面側の肉厚を挿入方向に漸増させて形成されていることを特徴とする。
請求項４に係る発明は、被処理体を支持する支持部を有する移載機構により、上記被処理体を予め加熱された処理室内に水平方向から挿入移載して熱処理する熱処理方法において、挿入時差による上記被処理体の面内温度差を低減すべく上記支持部の熱容量が挿入方向に漸増するように支持部の肉厚を挿入方向後端から先端に向って漸次増大させて形成することにより、被処理体の挿入方向先端側の温度上昇を抑えて被処理体後端部の挿入時点での面内温度差を低減することを特徴とする。
【０００９】
【実施の形態】
以下に、本発明の実施の形態を添付図面に基づいて詳述する。
【００１０】
先ず、本発明が適用される熱処理装置を含む複数の処理室を備えたマルチチャンバ型処理装置の概略的平面構成を示す図３において、１はローダ室を構成する第１の移載室であり、この移載室１の両側にはゲートバルブＧ１，Ｇ２を介して第１のカセット室２Ａおよび第２のカセット室２Ｂが接続されている。これらカセット室２Ａ，２Ｂは、複数枚（例えば２５枚）の被処理体（被処理基板）例えば半導体ウエハＷを所定の間隔（例えば５ｍｍ間隔）で収容する容器たるカセット３を収容するチャンバとして形成されている。
【００１１】
上記カセット室２Ａ，２Ｂには、外部との間を開閉するゲートバルブＧ３，Ｇ４が設けられ、カセット室２Ａ，２Ｂ内には上記カセット３をウエハＷが水平な状態で支持するアームを有してカセット３を外部との間で上記ゲートバルブＧ３，Ｇ４を介して搬入搬出するカセット搬入搬出機構と、搬入されたカセット３を上記アームから受け取って高さ調整可能に支持する昇降可能なカセットステージとを備えている（図示省略）。第１の移載室１およびカセット室２Ａ，２Ｂは、不活性ガス例えば窒素（Ｎ₂）ガスの供給により、大気圧（常圧）以上、例えば大気圧の不活性ガス雰囲気に維持されていることが好ましい。
【００１２】
上記第１の移載室１内には、第１の移載機構４と、ウエハＷの中心およびオリエンテーションフラット（オリフラともいう）の位置合せを行うための回転ステージ５とが配設されている。この回転ステージ５は、ウエハＷの周縁位置を検知する図示しない光センサおよび上記第１の移載機構４とともにウエハＷの位置合せ機構を構成している。例えばウエハＷの中心が回転ステージ５の中心からずれていることが検出された場合には、第１の移載機構４によりウエハＷの位置を修正する。
【００１３】
上記第１の移載機構４は、水平に回動および伸縮可能なアーム、例えば多関節アームからなり、先端（ウエハ支持部）には支持したウエハＷを真空吸着する吸引孔６を有していることが好ましい。上記第１ないし第２のカセット室２Ａ，２Ｂ内のカセット３と、上記回転ステージ５と、後述の真空予備室１１Ａ，１１Ｂとの間でウエハＷの移載を行うように構成されている。
【００１４】
上記第１の移載室１の後方には、ゲートバルブＧ５，Ｇ６を介して第１の真空予備室７Ａおよび第２の真空予備室７Ｂが接続されている。これら真空予備室７Ａ，７Ｂは、室内を所定の圧力１０^-3〜１０^-4Ｔｏｒｒに減圧する減圧ポンプおよび室内を不活性ガス例えば窒素ガスで常圧復帰させるためのガス源が接続されている。また、真空予備室７Ａ，７Ｂには、処理前のウエハを予め加熱（予熱）する加熱手段および処理後のウエハを冷却する冷却手段を備えていることが好ましい。
【００１５】
上記第１および第２の真空予備室７Ａ，７Ｂの後方には、ゲートバルブＧ７，Ｇ８を介して第２の移載室８が接続されている。この第２の移載室８内には、上記真空予備室７Ａ，７Ｂと、後述の処理室１０Ａ〜１０Ｃとの間でウエハＷの移載を行うための例えば多関節アームからなる第２の移載機構９が配置されている。この第２の移載機構９の詳細については後述する。
【００１６】
上記第２の移載室８には、ゲートバルブＧ９〜Ｇ１１を介して左右および後方の三方に第１〜第３の処理室１０Ａ〜１０Ｃが接続され、これら移載室８および処理室１０Ａ〜１０Ｃは減圧ポンプにより所定の圧力例えば１０^-3〜１０^-6Ｔｏｒｒに減圧されるようになっている。上記処理室１０Ａ〜１０Ｃは、同一の処理を行なうように構成されていてもよく、あるいは異なる処理を行なうように構成されていてもよい。
【００１７】
上記処理室１０Ａ〜１０Ｃの少なくとも一つは、熱処理装置、例えば枚葉式減圧ＣＶＤ装置の処理室１０として構成されている。この熱処理装置の処理室１０は、例えば図４に示すように偏平な円形容器状の石英製チャンバからなっている。この処理室１０の外側の上部と下部には、例えばカンタル線等の発熱抵抗体からなる面状の加熱部（ヒータ）１１ａ，１１ｂが設けられ、処理室１０内を所定の熱処理温度、例えば１，０００℃に加熱し得るように構成されている。
【００１８】
上記処理室１０は、例えばアルミニウム合金製のケーシング１２の内部に断熱空間、あるいはグラスウール等の断熱材１３を介して収容されている。上記ケーシング１２は、外部への熱的影響を防止するために、冷却構造例えば冷却水通路を有する水冷構造とされていることが好ましい。
【００１９】
上記処理室１０の側部には、ウエハＷを搬入搬出する出入口１４が設けられ、この出入口１４にはこれを開閉するゲートバルブＧ（Ｇ９〜Ｇ１１）が設けられている。また、処理室１０の側部には、処理室１０内を減圧排気する減圧ポンプ等に通じる排気口１５と、処理室１０内に処理ガス、不活性ガス例えば窒素ガス、クリーニングガス等を供給するこれらのガス源に通じるガス供給口１６とが設けられている。
【００２０】
また、処理室１０内には、搬入されたウエハＷを保持する保持手段として、図示例ではウエハＷの下面を保持すべく複数例えば３本の石英製保持ピン（ウエハ保持ピンともいう）１７が設けられている。なお、上記保持手段としては、ウエハＷの被処理面とは反対側の面（下面または上面）全体を保持する面状のもの、あるいはウエハＷの周縁部を保持する環状のもの等であってもよい。また、上記保持手段は、移載機構（上記第２の移載機構）９との間でウエハＷの受取り受渡しを行なう上下動機構を有していてもよい。
【００２１】
上記移載機構９は、図１ないし図２に示すように基台１８の上部に水平に回動および伸縮可能な多関節アームからなる移載アーム１９を設け、この移載アーム１９の先端にウエハＷを支持する支持部（ウエハ支持部ともいう）２０を有している。上記移載アーム１９は、基台１８の上部に一端が水平に回動可能に設けられた基部アーム部１９ａと、この基部アーム部１９ａの他端に一端が水平に回動可能に設けられた中間アーム部１９ｂと、この中間アーム部１９ｂの他端に一端が水平に回動可能に設けられた先端アーム部１９ｃとから主に構成されており、この先端アーム部１９ｃに上記ウエハ支持部２０が設けられている。なお、上記処理室１０内のウエハ保持ピン１７側がウエハ支持部２０との間でウエハＷの受取り受渡しを行なうための上下動機構を有しない場合には、上記移載アーム１９側が上下動可能に構成されていることが好ましい。
【００２２】
上記移載機構９は、ウエハＷの熱処理を行なう場合、予め加熱された上記処理室１０内に移載アーム１９の伸張動作でウエハ支持部２０上のウエハＷを水平方向から挿入（搬入）してウエハ保持ピン１７上に移載した後、移載アーム１９を移載室（第２の移載室）８側に収縮させる。また、熱処理が終了した場合には、上記とは逆の動作で熱処理後のウエハＷを処理室１０外に搬出する。
【００２３】
上記ウエハＷを予め加熱された処理室１０内に水平方向から挿入する場合、その挿入過程で先ずウエハＷの挿入方向先端が最初に加熱され、次いでウエハＷの後端が遅れて加熱される。このようにウエハ面内の挿入時差に起因して生じる温度差を低減するために、上記移載機構９のウエハ支持部２０がその熱容量を挿入方向に変化させて形成されている。図示例のウエハ支持部２０においては、ウエハＷとほぼ同じ平面形状、例えばウエハＷの直径と同じ直径Ｄの円板状に形成され、その上面がウエハＷを載置する平坦な載置面２１とされ、下面側の肉厚ｔが挿入方向Ｘの後端から先端に向って漸増して形成されている。
【００２４】
上記ウエハ支持部２０の材質としては、例えばアルミナ（Ａｌ₂Ｏ₃）が用いられるが、炭化ケイ素（ＳｉＣ）、石英等であってもよい。また、処理室１０内に図４に示すようなウエハ保持ピン１７を有する場合には、上記ウエハ支持部２０には図５に示すようにウエハ保持ピン１７との干渉を避けるための切欠部２２が設けられていることが好ましい。
【００２５】
次に、以上のように構成された熱処理装置の作用について述べる。熱処理装置の処理室１０内は、加熱部１１ａ，１１ｂによって予め所定の熱処理温度に加熱されている。この加熱状態の処理室１０内にウエハＷが移載機構９によって水平方向から挿入される。この場合、上記ウエハＷは、カセット室２Ａもしくは２Ｂのカセット３から真空予備室７Ａもしくは７Ｂ内に移送されており、この真空予備室７Ａもしくは７Ｂ内から移載機構９における移載アーム１９のウエハ支持部２０上に支持されて移載室８内を経由し、上記処理室１０内に開状態のゲートバルブＧを介して水平方向から挿入され、ウエハ保持ピン１７上に移載される。移載後、移載機構９の移載アーム１９は収縮して移載室８内に戻され、処理室１０のゲートバルブＧが閉じられる。
【００２６】
上記処理室１０内は、排気口１５からの減圧排気により所定の減圧状態に維持され、この状態でガス供給口１６から処理ガスを上記加熱状態のウエハＷの被処理面に供給することにより、ウエハＷの被処理面にはＣＶＤ法による成膜処理が面内均一に施される。所定の処理が終了したなら、処理室１０内を不活性ガスでパージした後、ゲートバルブＧを開けて移載機構９により処理済みのウエハＷが処理室１０内から搬出され、真空予備室７Ａもしくは７Ｂ等を介してカセット室２Ａもしくは２Ｂのカセット３に収容される。このようにして順次連続的にウエハＷの熱処理を含む処理が行なわれる。
【００２７】
ところで、上記ウエハＷを予め加熱された処理室１０内に水平方向から挿入する場合、先ずウエハＷの挿入方向Ｘの先端が最初に挿入され、次いでウエハＷの後端が遅れて挿入されため、この挿入時差に起因してウエハＷの面内には挿入方向Ｘに温度分布ないし温度差が生じる。上記移載機構９のウエハ支持部１０の肉厚ｔが挿入方向Ｘに一定であった従来の熱処理装置においては、ウエハＷを処理室１０内に挿入した際に、ウエハＷの挿入方向先端部Ａは図６の昇温曲線Ｌ１で示すように昇温し、ウエハＷの後端部Ｂは挿入時点Ｐから昇温曲線Ｌ２で示すように昇温し、その挿入時点Ｐでの面内温度差がＴｆであった。
【００２８】
一方、本実施の形態の熱処理装置においては、上記面内温度差を低減すべく上記移載機構９のウエハ支持部２０の熱容量が挿入方向Ｘに漸増するように肉厚ｔを挿入方向後端から先端に向って漸次増大させて形成されている。このため、上記ウエハＷの下面に接しているウエハ支持部２０の挿入方向先端側の熱容量が大きい分、ウエハＷの挿入方向先端側の温度上昇が抑えられる。これにより、ウエハＷの挿入方向先端部Ａは図６の昇温曲線Ｌ３で示すように昇温するため、ウエハ後端部Ｂの挿入時点Ｐでの面内温度差が上記Ｔｆよりも小さいＴｓに低減する。
【００２９】
このように上記熱処理装置によれば、ウエハＷを支持するウエハ支持部２０を有する移載機構９により、上記ウエハＷを予め加熱された処理室１０内に水平方向から挿入移載して熱処理する熱処理装置において、上記ウエハ支持部２０の熱容量を、挿入時差による上記ウエハＷの面内温度差を低減すべく挿入方向に変化させてなるため、挿入時差により生じる上記ウエハＷの面内温度差を可及的に低減することが可能となり、上記ウエハＷの品質およびスループットの向上が図れる。
【００３０】
この場合、上記ウエハ支持部２０の肉厚ｔを挿入方向に漸増させて熱容量を漸増させているため、比較的簡単な構造で挿入時差による上記ウエハＷの面内温度差を容易に低減することが可能となる。また、上記ウエハ支持部２０が上記ウエハＷとほぼ同じ平面形状に形成され、上面を上記ウエハＷの載置面２１とし、下面側の肉厚ｔを挿入方向Ｘに漸増させて形成されているため、比較的簡単な構造で挿入時差による上記ウエハＷの面内温度差を効率よく低減することが可能となる。
【００３１】
以上、本発明の実施の形態を図面により詳述してきたが、本発明は上記実施の形態に限定されるものではなく、本発明の要旨を逸脱しない範囲での種々の設計変更等が可能である。例えば、移載機構９のウエハ支持部２０としては、その熱容量を挿入方向に比例的に変化させるために、図７に示すように下面側の肉厚ｔを挿入方向後端から先端に放物曲線状に漸増させて形成されていてもよい。
【００３２】
ウエハＷの面内温度差は、予め加熱された処理室１０内へのウエハＷの挿入時だけでなく、搬出時にも生じる。この場合、高温の処理室１０から常温の移載室８にウエハＷが搬出されるので、上記とは逆に、搬出方向先端側の降温を抑えるべくウエハ支持部２０の肉厚を搬出方向後端から先端に漸増させて形成することが好ましい。このようにウエハ挿入時とウエハ搬出時では逆の構造のウエハ支持部２０が要求されるため、例えば図８に示すように移載機構９の先端アーム部１９ｃを中央で回転可能に支持された構造にし、この先端アーム部１９ｃの一端に挿入用のウエハ支持部２０Ａを設け、先端アーム１９ｃの他端に搬出用のウエハ支持部２０Ｂを設けるようにするとよい。
【００３３】
上記実施の形態では、挿入時差によるウエハＷの面内温度差を低減するために、ウエハ支持部２０の熱容量を挿入方向に変化させたが、ウエハ支持部２０の吸熱特性例えば熱吸収率を挿入方向に変化させてもよい。この場合、例えばウエハ支持部２０の密度、材質等を挿入方向に変化させて形成すればよく、必ずしも肉厚ｔを変化させる必要はない。本発明が適用される熱処理装置としては、ＣＶＤ処理以外に例えば酸化、拡散、アニール等の処理を行なうものであってもよい。また、被処理体としては、半導体ウエハ以外に例えばＬＣＤ基板等も適用可能である。
【００３４】
【発明の効果】
以上要するに本発明によれば、次のような優れた効果が得られる。
【００３５】
（１）請求項１に係る発明によれば、被処理体を支持する支持部を有する移載機構により、上記被処理体を予め加熱された処理室内に水平方向から挿入移載して熱処理する熱処理装置において、上記支持部の熱容量または吸熱特性を、挿入時差による上記被処理体の面内温度差を低減すべく挿入方向に変化させてなるため、挿入時差により生じる上記被処理体の面内温度差を可及的に低減することが可能となり、上記被処理体の品質およびスループットの向上が図れる。
【００３６】
（２）請求項２に係る発明によれば、上記支持部が肉厚を挿入方向に漸増させて形成されているため、比較的簡単な構造で挿入時差による上記被処理体の面内温度差を容易に低減することが可能となる。
【００３７】
（３）請求項３に係る発明によれば、上記支持部が上記被処理体とほぼ同じ平面形状に形成され、上面を上記被処理体の載置面とし、下面側の肉厚を挿入方向に漸増させて形成されているため、比較的簡単な構造で挿入時差による上記被処理体の面内温度差を効率よく低減することが可能となる。
（４）請求項４に係る発明によれば、被処理体を支持する支持部を有する移載機構により、上記被処理体を予め加熱された処理室内に水平方向から挿入移載して熱処理する熱処理方法において、挿入時差による上記被処理体の面内温度差を低減すべく上記支持部の熱容量が挿入方向に漸増するように支持部の肉厚を挿入方向後端から先端に向って漸次増大させて形成することにより、被処理体の挿入方向先端側の温度上昇を抑えて被処理体後端部の挿入時点での面内温度差を低減するため、上記被処理体の品質およびスループットの向上が図れる。
【図面の簡単な説明】
【図１】本発明の実施の形態を示す熱処理装置における移載機構の側面図である。
【図２】図１の移載機構の平面図である。
【図３】図１の熱処理装置を備えたマルチチャンバ型処理装置の概略的構成を示す平面図である。
【図４】図１の熱処理装置の一例を示す断面図である。
【図５】移載機構の支持部の平面図である。
【図６】ウエハ挿入後のウエハ温度の変化を示すグラフである。
【図７】本発明の他の実施の形態を示す移載機構の支持部の側面図である。
【図８】本発明の他の実施の形態を示す移載機構の斜視図である。
【符号の説明】
Ｗ半導体ウエハ（被処理体）
１０処理室
１９移載機構
２０ウエハ支持部（支持部）
２１載置面[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a heat treatment apparatus and a heat treatment method .
[0002]
[Prior art]
In a semiconductor device manufacturing process, various types of heat treatment apparatuses are used to perform processes such as oxidation, diffusion, CVD (Chemical Vapor Deposition), and annealing on a semiconductor wafer that is an object to be processed. As one of the heat treatment apparatuses of this type, a single wafer type in which the object to be treated is inserted and transferred from a horizontal direction into a preheated treatment chamber by a transfer mechanism having a support part for supporting the object to be treated, and then heat treated. A heat treatment apparatus has been proposed.
[0003]
According to the heat treatment apparatus, since the processing chamber is preheated, the temperature of the wafer can be quickly raised to perform heat treatment, and throughput can be improved.
[0004]
[Problems to be solved by the invention]
However, in the above heat treatment apparatus, when a wafer is inserted into a preheated processing chamber, the temperature distribution in the insertion direction, that is, in-plane, is caused by the insertion time difference generated between the front end side and the rear end side in the insertion direction. A temperature difference occurs. When this in-plane temperature difference is large, there is a problem that slips (crystal misalignment) occur in the wafer, leading to a decrease in quality and a decrease in yield of semiconductor devices.
[0005]
Therefore, the present invention has been made to solve the above-described problems, and as much as possible the in-plane temperature difference of the object to be processed due to the insertion time difference when the object to be processed is inserted into the processing chamber heated in advance from the horizontal direction. It is an object of the present invention to provide a heat treatment apparatus and a heat treatment method that can be reduced to a minimum.
[0006]
[Means for Solving the Problems]
In order to achieve the above object, the invention according to claim 1 of the present invention is such that the object to be processed is inserted from a horizontal direction into a preheated processing chamber by a transfer mechanism having a support part for supporting the object to be processed. In the heat treatment apparatus for transferring and heat-treating, the heat capacity or endothermic characteristic of the support portion is changed in the insertion direction so as to reduce the in-plane temperature difference of the object to be processed due to the insertion time difference.
[0007]
The invention according to claim 2 is characterized in that the support portion in the heat treatment apparatus according to claim 1 is formed by gradually increasing the thickness in the insertion direction.
[0008]
According to a third aspect of the present invention, in the heat treatment apparatus according to the first aspect, the support portion is formed in substantially the same planar shape as the object to be processed, and the upper surface is a mounting surface of the object to be processed, and It is characterized in that the thickness is gradually increased in the insertion direction.
According to a fourth aspect of the present invention, there is provided a heat treatment method for performing heat treatment by inserting and transferring the object to be processed from a horizontal direction into a preheated processing chamber by means of a transfer mechanism having a support part for supporting the object to be processed. In order to reduce the in-plane temperature difference of the object to be processed due to time difference, the support portion is formed by gradually increasing the thickness of the support portion from the rear end to the front end in the insertion direction so that the heat capacity of the support portion gradually increases in the insertion direction. Thus, the temperature rise at the front end side in the insertion direction of the object to be processed is suppressed to reduce the in-plane temperature difference at the time of insertion of the rear end of the object to be processed.
[0009]
Embodiment
Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.
[0010]
First, in FIG. 3 showing a schematic plan configuration of a multi-chamber processing apparatus including a plurality of processing chambers including a heat treatment apparatus to which the present invention is applied, 1 is a first transfer chamber constituting a loader chamber. The first cassette chamber 2A and the second cassette chamber 2B are connected to both sides of the transfer chamber 1 via gate valves G1 and G2. These cassette chambers 2A and 2B are formed as a chamber for accommodating a cassette 3 as a container for accommodating a plurality of (for example, 25) objects to be processed (substrates to be processed) such as semiconductor wafers W at predetermined intervals (for example, 5 mm intervals). Has been.
[0011]
The cassette chambers 2A and 2B are provided with gate valves G3 and G4 for opening and closing between the cassette chambers 2A and 2B. The cassette chambers 2A and 2B have arms for supporting the cassette 3 in a horizontal state with the wafer W in a horizontal state. A cassette loading / unloading mechanism for loading / unloading the cassette 3 to / from the outside via the gate valves G3 and G4, and a cassette stage capable of moving up and down for receiving the loaded cassette 3 from the arm and supporting the cassette 3 so that the height can be adjusted. (Not shown). The first transfer chamber 1 and the cassette chambers 2A and 2B are maintained in an inert gas atmosphere at atmospheric pressure (normal pressure) or higher, for example, atmospheric pressure by supplying an inert gas such as nitrogen (N ₂ ) gas. It is preferable.
[0012]
In the first transfer chamber 1, a first transfer mechanism 4 and a rotary stage 5 for aligning the center of the wafer W and an orientation flat (also referred to as an orientation flat) are disposed. . The rotary stage 5 constitutes a wafer W alignment mechanism together with an optical sensor (not shown) that detects the peripheral position of the wafer W and the first transfer mechanism 4. For example, when it is detected that the center of the wafer W is deviated from the center of the rotary stage 5, the position of the wafer W is corrected by the first transfer mechanism 4.
[0013]
The first transfer mechanism 4 is composed of an arm that can be rotated and extended horizontally, for example, an articulated arm, and has a suction hole 6 for vacuum-sucking the wafer W supported at the tip (wafer support portion). Preferably it is. The wafer W is transferred between the cassettes 3 in the first and second cassette chambers 2A and 2B, the rotary stage 5, and the vacuum preliminary chambers 11A and 11B described later.
[0014]
A first vacuum preparatory chamber 7A and a second vacuum preparatory chamber 7B are connected to the rear of the first transfer chamber 1 through gate valves G5 and G6. These vacuum preparatory chambers 7A and 7B are connected to a decompression pump that depressurizes the chamber to a predetermined pressure of 10 ⁻³ to 10 ⁻⁴ Torr and a gas source for returning the chamber to normal pressure with an inert gas such as nitrogen gas. . The vacuum preliminary chambers 7A and 7B are preferably provided with a heating means for preheating (preheating) the wafer before processing and a cooling means for cooling the processed wafer.
[0015]
A second transfer chamber 8 is connected to the rear of the first and second vacuum preliminary chambers 7A and 7B via gate valves G7 and G8. In this second transfer chamber 8, a second articulated arm, for example, comprising a multi-joint arm for transferring the wafer W between the vacuum preliminary chambers 7A, 7B and the processing chambers 10A to 10C described later. A transfer mechanism 9 is arranged. Details of the second transfer mechanism 9 will be described later.
[0016]
The first transfer chamber 8 and the processing chambers 10A to 10C are connected to the second transfer chamber 8 through gate valves G9 to G11 on the left, right, and rear three sides. 10C is decompressed to a predetermined pressure, for example, 10 ⁻³ to 10 ⁻⁶ Torr by a decompression pump. The processing chambers 10A to 10C may be configured to perform the same processing, or may be configured to perform different processing.
[0017]
At least one of the processing chambers 10A to 10C is configured as a processing chamber 10 of a heat treatment apparatus, for example, a single wafer type low pressure CVD apparatus. The processing chamber 10 of this heat treatment apparatus is composed of a flat circular container-like quartz chamber, for example, as shown in FIG. In the upper and lower portions of the outside of the processing chamber 10, planar heating portions (heaters) 11a and 11b made of a heating resistor such as Kanthal wire are provided, and a predetermined heat treatment temperature, for example, 1 is set in the processing chamber 10. It can be heated to 1,000 ° C.
[0018]
The processing chamber 10 is accommodated inside a casing 12 made of, for example, an aluminum alloy via a heat insulating space 13 or a heat insulating material 13 such as glass wool. The casing 12 is preferably a cooling structure, for example, a water cooling structure having a cooling water passage, in order to prevent thermal influence on the outside.
[0019]
An inlet / outlet port 14 for loading / unloading the wafer W is provided at the side of the processing chamber 10, and a gate valve G (G9 to G11) for opening / closing the wafer W is provided at the inlet / outlet port 14. Further, an exhaust port 15 leading to a decompression pump or the like for decompressing and exhausting the inside of the processing chamber 10 is supplied to a side portion of the processing chamber 10, and a processing gas, an inert gas such as nitrogen gas, or a cleaning gas is supplied into the processing chamber 10 A gas supply port 16 communicating with these gas sources is provided.
[0020]
In the processing chamber 10, a plurality of, for example, three quartz holding pins (also referred to as wafer holding pins) 17 are provided as holding means for holding the loaded wafer W in the illustrated example in order to hold the lower surface of the wafer W. Is provided. The holding means may be a planar one that holds the entire surface (lower surface or upper surface) opposite to the surface to be processed of the wafer W, or an annular one that holds the peripheral edge of the wafer W. Also good. The holding means may have a vertical movement mechanism for receiving and transferring the wafer W to and from the transfer mechanism (second transfer mechanism) 9.
[0021]
As shown in FIGS. 1 and 2, the transfer mechanism 9 is provided with a transfer arm 19 composed of a multi-joint arm that can be rotated and extended horizontally on an upper portion of a base 18. A support unit (also referred to as a wafer support unit) 20 that supports the wafer W is provided. The transfer arm 19 is provided with a base arm portion 19a having one end horizontally provided at the upper portion of the base 18 and one end horizontally provided at the other end of the base arm portion 19a. The intermediate arm portion 19b is mainly composed of an intermediate arm portion 19b and a distal end arm portion 19c having one end rotatably provided at the other end of the intermediate arm portion 19b. Is provided. When the wafer holding pin 17 side in the processing chamber 10 does not have a vertical movement mechanism for receiving and delivering the wafer W to and from the wafer support portion 20, the transfer arm 19 side can be moved up and down. It is preferable to be configured.
[0022]
When performing heat treatment of the wafer W, the transfer mechanism 9 inserts (loads) the wafer W on the wafer support unit 20 in the horizontal direction by the extension operation of the transfer arm 19 into the processing chamber 10 heated in advance. After the transfer onto the wafer holding pins 17, the transfer arm 19 is contracted to the transfer chamber (second transfer chamber) 8 side. Further, when the heat treatment is completed, the wafer W after the heat treatment is carried out of the processing chamber 10 by an operation reverse to the above.
[0023]
When the wafer W is inserted into the pre-heated processing chamber 10 from the horizontal direction, the front end of the wafer W in the insertion direction is first heated in the insertion process, and then the rear end of the wafer W is heated with a delay. Thus, in order to reduce the temperature difference caused by the insertion time difference in the wafer surface, the wafer support portion 20 of the transfer mechanism 9 is formed by changing its heat capacity in the insertion direction. In the illustrated wafer support portion 20, it is formed in a disk shape having substantially the same planar shape as the wafer W, for example, a diameter D that is the same as the diameter of the wafer W, and a flat placement surface 21 on which the wafer W is placed. The thickness t on the lower surface side is gradually increased from the rear end to the front end in the insertion direction X.
[0024]
For example, alumina (Al ₂ O ₃ ) is used as the material of the wafer support 20, but silicon carbide (SiC), quartz, or the like may be used. When the processing chamber 10 has the wafer holding pins 17 as shown in FIG. 4, the wafer support portion 20 has a notch 22 for avoiding interference with the wafer holding pins 17 as shown in FIG. 5. Is preferably provided.
[0025]
Next, the operation of the heat treatment apparatus configured as described above will be described. The inside of the processing chamber 10 of the heat treatment apparatus is heated in advance to a predetermined heat treatment temperature by the heating units 11a and 11b. The wafer W is inserted into the heated processing chamber 10 from the horizontal direction by the transfer mechanism 9. In this case, the wafer W is transferred from the cassette 3 in the cassette chamber 2A or 2B to the vacuum preliminary chamber 7A or 7B, and the wafer of the transfer arm 19 in the transfer mechanism 9 is transferred from the vacuum preliminary chamber 7A or 7B. It is supported on the support unit 20, passes through the transfer chamber 8, is inserted into the processing chamber 10 through the open gate valve G from the horizontal direction, and is transferred onto the wafer holding pins 17. After the transfer, the transfer arm 19 of the transfer mechanism 9 contracts and returns to the transfer chamber 8, and the gate valve G of the processing chamber 10 is closed.
[0026]
The inside of the processing chamber 10 is maintained in a predetermined reduced pressure state by the reduced pressure exhaust from the exhaust port 15, and in this state, the processing gas is supplied from the gas supply port 16 to the surface to be processed of the wafer W in the heated state. A film-forming process by the CVD method is uniformly performed on the surface to be processed of the wafer W. When the predetermined processing is completed, the inside of the processing chamber 10 is purged with an inert gas, then the gate valve G is opened, and the processed wafer W is unloaded from the processing chamber 10 by the transfer mechanism 9, and the vacuum preliminary chamber 7A. Alternatively, it is accommodated in the cassette 3 in the cassette chamber 2A or 2B via 7B or the like. In this way, the processing including the heat treatment of the wafers W is sequentially and sequentially performed.
[0027]
By the way, when the wafer W is inserted into the processing chamber 10 heated in advance from the horizontal direction, first, the front end of the insertion direction X of the wafer W is inserted first, and then the rear end of the wafer W is inserted with a delay. Due to this insertion time difference, a temperature distribution or temperature difference in the insertion direction X occurs in the plane of the wafer W. In the conventional heat treatment apparatus in which the thickness t of the wafer support portion 10 of the transfer mechanism 9 is constant in the insertion direction X, when the wafer W is inserted into the processing chamber 10, the front end portion of the wafer W in the insertion direction. A is heated as shown by a temperature rise curve L1 in FIG. 6, and the rear end B of the wafer W is heated from the insertion time P as shown by the temperature rise curve L2, and the in-plane temperature at the insertion time P is shown. The difference was Tf.
[0028]
On the other hand, in the heat treatment apparatus of the present embodiment, the thickness t is set to the rear end in the insertion direction so that the heat capacity of the wafer support portion 20 of the transfer mechanism 9 gradually increases in the insertion direction X in order to reduce the in-plane temperature difference. It is formed to gradually increase from the tip toward the tip. For this reason, since the heat capacity at the front end side in the insertion direction of the wafer support portion 20 in contact with the lower surface of the wafer W is large, the temperature rise at the front end side in the insertion direction of the wafer W can be suppressed. As a result, the tip A of the wafer W in the insertion direction is heated as shown by the temperature rise curve L3 in FIG. 6, and therefore the in-plane temperature difference at the insertion point P of the wafer rear end B is smaller than Tf. To reduce.
[0029]
As described above, according to the heat treatment apparatus, the wafer W is inserted and transferred from the horizontal direction into the preheated processing chamber 10 by the transfer mechanism 9 having the wafer support portion 20 that supports the wafer W, and heat-treated. In the heat treatment apparatus, the heat capacity of the wafer support portion 20 is changed in the insertion direction so as to reduce the in-plane temperature difference of the wafer W due to the insertion time difference. Therefore, the in-plane temperature difference of the wafer W caused by the insertion time difference is reduced. It is possible to reduce as much as possible, and the quality and throughput of the wafer W can be improved.
[0030]
In this case, since the heat capacity is gradually increased by gradually increasing the thickness t of the wafer support portion 20 in the insertion direction, the in-plane temperature difference of the wafer W due to the insertion time difference can be easily reduced with a relatively simple structure. Is possible. Further, the wafer support portion 20 is formed in substantially the same planar shape as the wafer W, the upper surface is used as the mounting surface 21 of the wafer W, and the thickness t on the lower surface side is gradually increased in the insertion direction X. Therefore, the in-plane temperature difference of the wafer W due to the insertion time difference can be efficiently reduced with a relatively simple structure.
[0031]
Although the embodiments of the present invention have been described in detail with reference to the drawings, the present invention is not limited to the above-described embodiments, and various design changes and the like can be made without departing from the gist of the present invention. is there. For example, the wafer support portion 20 of the transfer mechanism 9 has a parabolic thickness t on the lower surface side from the rear end to the front end in the insertion direction, as shown in FIG. 7, in order to change the heat capacity in proportion to the insertion direction. It may be formed by gradually increasing in a curved line.
[0032]
The in-plane temperature difference of the wafer W occurs not only when the wafer W is inserted into the preheated processing chamber 10 but also when it is unloaded. In this case, since the wafer W is carried out from the high temperature processing chamber 10 to the room temperature transfer chamber 8, contrary to the above, the thickness of the wafer support portion 20 is adjusted after the carrying out direction in order to suppress the temperature drop at the front end side in the carrying out direction. It is preferable to gradually increase from the end to the tip. Thus, when the wafer is inserted and when the wafer is unloaded, the wafer support portion 20 having the opposite structure is required. For example, as shown in FIG. 8, the front end arm portion 19c of the transfer mechanism 9 is rotatably supported at the center. It is preferable to provide a structure so that an insertion wafer support 20A is provided at one end of the tip arm 19c, and a carry-out wafer support 20B is provided at the other end of the tip arm 19c.
[0033]
In the above embodiment, in order to reduce the in-plane temperature difference of the wafer W due to the insertion time difference, the heat capacity of the wafer support 20 is changed in the insertion direction, but the heat absorption characteristics of the wafer support 20 such as the heat absorption rate are inserted. The direction may be changed. In this case, for example, the wafer support 20 may be formed by changing the density, material, and the like in the insertion direction, and it is not always necessary to change the thickness t. As a heat treatment apparatus to which the present invention is applied, other than CVD processing, for example, processing such as oxidation, diffusion and annealing may be performed. In addition to the semiconductor wafer, for example, an LCD substrate or the like is applicable as the object to be processed.
[0034]
【The invention's effect】
In short, according to the present invention, the following excellent effects can be obtained.
[0035]
(1) According to the first aspect of the present invention, the object to be processed is inserted and transferred from the horizontal direction into the preheated processing chamber and heat-treated by the transfer mechanism having the support portion that supports the object to be processed. In the heat treatment apparatus, the heat capacity or endothermic characteristic of the support part is changed in the insertion direction so as to reduce the in-plane temperature difference of the object to be processed due to the insertion time difference. The temperature difference can be reduced as much as possible, and the quality and throughput of the object to be processed can be improved.
[0036]
(2) According to the invention of claim 2, since the support portion is formed by gradually increasing the thickness in the insertion direction, an in-plane temperature difference of the object to be processed due to a difference in insertion time with a relatively simple structure. Can be easily reduced.
[0037]
(3) According to the invention of claim 3, the support part is formed in substantially the same planar shape as the object to be processed, the upper surface is the mounting surface of the object to be processed, and the thickness on the lower surface side is the insertion direction. Accordingly, the in-plane temperature difference of the object to be processed due to the insertion time difference can be efficiently reduced with a relatively simple structure.
(4) According to the invention of claim 4, the object to be processed is inserted and transferred from the horizontal direction into the preheated processing chamber and heat-treated by the transfer mechanism having the support portion that supports the object to be processed. In the heat treatment method, the thickness of the support portion is gradually increased from the rear end to the front end in the insertion direction so that the heat capacity of the support portion gradually increases in the insertion direction in order to reduce the in-plane temperature difference of the workpiece due to the difference in insertion time. In order to suppress the temperature rise at the front end side in the insertion direction of the object to be processed and reduce the in-plane temperature difference at the time of insertion of the rear end of the object to be processed, the quality and throughput of the object to be processed are reduced. Improvement can be achieved.
[Brief description of the drawings]
FIG. 1 is a side view of a transfer mechanism in a heat treatment apparatus showing an embodiment of the present invention.
FIG. 2 is a plan view of the transfer mechanism of FIG.
3 is a plan view showing a schematic configuration of a multi-chamber type processing apparatus provided with the heat treatment apparatus of FIG. 1. FIG.
4 is a cross-sectional view showing an example of the heat treatment apparatus of FIG.
FIG. 5 is a plan view of a support portion of the transfer mechanism.
FIG. 6 is a graph showing changes in wafer temperature after wafer insertion.
FIG. 7 is a side view of a support portion of a transfer mechanism showing another embodiment of the present invention.
FIG. 8 is a perspective view of a transfer mechanism showing another embodiment of the present invention.
[Explanation of symbols]
W Semiconductor wafer (object to be processed)
DESCRIPTION OF SYMBOLS 10 Processing chamber 19 Transfer mechanism 20 Wafer support part (support part)
21 Placement surface

Claims

In a heat treatment apparatus for performing heat treatment by inserting and transferring the object to be processed from a horizontal direction into a preheated processing chamber by a transfer mechanism having a support part for supporting the object to be processed, the heat capacity or heat absorption characteristics of the support part is obtained. A heat treatment apparatus characterized by being changed in the insertion direction so as to reduce the in-plane temperature difference of the object to be processed due to the insertion time difference.

The heat treatment apparatus according to claim 1, wherein the support portion is formed by gradually increasing the thickness in the insertion direction.

The support part is formed in substantially the same planar shape as the object to be processed, and the upper surface is a mounting surface of the object to be processed, and the thickness on the lower surface side is gradually increased in the insertion direction. The heat treatment apparatus according to claim 1.

In the heat treatment method of inserting and transferring the object to be processed from a horizontal direction into a preheated processing chamber by a transfer mechanism having a support part for supporting the object to be processed, a surface of the object to be processed due to insertion time difference. In order to reduce the internal temperature difference, the thickness of the support part is gradually increased from the rear end to the front end in the insertion direction so that the heat capacity of the support part gradually increases in the insertion direction. A heat treatment method characterized by suppressing a temperature rise on the front end side and reducing an in-plane temperature difference at the time of insertion of the rear end portion of the object to be processed.