JP3994000B2

JP3994000B2 - Thin film deposition apparatus and method

Info

Publication number: JP3994000B2
Application number: JP2001368425A
Authority: JP
Inventors: 典明谷; 寿弘鈴木; 孝文松元; 幸一半澤
Original assignee: Ulvac Inc
Current assignee: Ulvac Inc
Priority date: 2001-12-03
Filing date: 2001-12-03
Publication date: 2007-10-17
Anticipated expiration: 2021-12-03
Also published as: JP2003166055A

Description

【０００１】
【発明の属する技術分野】
本発明は、回転基板上に薄膜を成膜する装置及びこの装置を用いて薄膜を成膜する方法に関する。例えば、ガラス基板上にスパッタ装置などで成膜を行うと、基板上の所望位置にスパッタ粒子が堆積して薄膜が形成される際に、成膜条件を均一にする目的で用いる回転基板方式では、その径方向において、ターゲット中心に対応する基板部分をピークにするような膜厚分布を有する薄膜が形成されることが多い。また、回転基板の円周方向においても回転する基板のどの部分から成膜を開始し終了したかによって、これらの部分を始端または終端とするような膜厚分布が生じることが多い。このような膜厚の散布度は、所望の膜厚値の数パーセント程度であることが多いが、光素子や光フィルタ等に用いられる光学薄膜分野においては、膜厚に起因して変化する光学膜厚（膜厚と屈折率との積）を制御するため、厳密に均等な膜厚の薄膜を成膜することが求められている。
【０００２】
【従来の技術】
従来、成膜条件の均一化を図るために基板を回転させ、この基板上に薄膜の成膜を行うスパッタ装置は図１に示す構成を有する。このものでは、装置チャンバ１内の上方に、回転軸２で軸支されて回転可能な基板ホルダ３を設け、該ホルダ３上にガラス基板４を取り付けている。また、装置チャンバ１の断面下方の一方の側面領域に、基板４方向に向けたＴｉターゲット５を載置したスパッタカソード６を成膜源として設置し、Ｔｉターゲット５とスパッタカソード６とで構成されるスパッタリングターゲットの外側に防着板７を覆設している。さらに、装置チャンバ１内の下方に、円形状の開口部８ａを有するシャッタ８を、回転軸９で軸支して該回転軸９まわりに回転可能にして設けている。（図２参照。）
【０００３】
ここで、図１のスパッタ装置において、基板ホルダ３の回転軸２とシャッタ８の回転軸９とはそれぞれ独立に作動できるようにしている。また、基板ホルダ３と基板４とには、基板４上に成膜された薄膜の膜厚を計測する膜厚モニタ１０が設けられている。膜厚モニタ１０は、発光部１０ａ₁〜１０ａ₃と、発光部１０ａ₁〜１０ａ₃にそれぞれ対応する受光部１０ｂ₁〜１０ｂ₃とから成り、発光部１０ａと受光部１０ｂとの組み合わせにより、第１モニタ１０ａ₁-１０ｂ₁、第２モニタ１０ａ₂-１０ｂ₂及び第３モニタ１０ａ₃-１０ｂ₃を構成している。このように、発光部１０ａ₁〜１０ａ₃と受光部１０ｂ₁〜１０ｂ₃とから成る光センサで複数のモニタ（第１乃至第３モニタ）を構成することにより、膜厚モニタ１０は、ガラス基板４と薄膜との光透過度を測定して、薄膜の膜厚や分布の均等性をモニタできる。また、装置チャンバ１は、排気ポンプ１１により真空排気できるように構成され、さらに、装置チャンバ１断面下方のスパッタリングターゲット側の領域にガス導入口１２ａを設け、該ガス導入口１２ａからスパッタガスを導入し、装置チャンバ１断面上方の基板ホルダ３の近傍領域にガス導入口１２ｂを設け、該ガス導入口１２ｂから反応性ガスを導入するようにしている。
【０００４】
ガラス基板４上に成膜を行うに際しては、まず、前処理として排気ポンプ１１によりチャンバ１内を真空排気した後、ガス導入口１２ａからスパッタガスとしてＡｒガスを導入し、シャッタ８を回転軸９まわりに回転させて開口部８ａがターゲット５上に位置しないように調整する。この状態で、スパッタカソード６に電力を印加して行うプレスパッタにより、ターゲット５表面をクリーニングする。その後、ガス導入口１２ａからスパッタガスとしてＡｒガスを導入すると共に、ガス導入口１２ｂから反応性ガスとして酸素ガスを導入し、さらに、シャッタ８を回転軸９まわりに回転させて開口部８ａがターゲット５上に位置するように調整し、スパッタカソード６に電力を印加してスパッタカソード６上のＴｉターゲット５をスパッタさせ、これにより、ＴｉＯ₂から成る酸化膜を基板４上に成膜する。このとき、基板ホルダ３は回転軸２まわりに回転しており、これに伴って基板４も回転されている。そして、基板４上に成膜される薄膜の膜厚を膜厚モニタ１０により計測しながら、基板４上のＴｉＯ₂の成膜を所定時間継続し、薄膜が所定膜厚に成膜できた時点で、再び、シャッタ８を回転させて開口部８ａがターゲット５上に位置しないように調整し、この状態で成膜を終了させる。
【０００５】
上記の従来の装置において、シャッタ８は、成膜の開始と終了とを切り替える手段として、あるいはプレスパッタ時に、ターゲット物質の基板４への飛来を妨げるものとして用いられているが、シャッタ８の開口部８ａの形状により基板４上の薄膜の膜厚分布を補正する機能も備えている。このように膜厚補正を可能にする形状の開口部を有するシャッタ（膜厚補正板）を備えるスパッタ装置として、特開平４−１７３９７２号公報の第５図に示す開口部の形状を有するシャッタ（膜厚補正板）を備えるものが開示されている。
【０００６】
ところが、このように形状が固定された開口部を有するシャッタ（膜厚補正板）では、スパッタ中における種々のスパッタ条件（真空度、ガス導入量、チャンバ内からの放出ガス量、スパッタ電圧、スパッタ電流等）の変化に対応することが困難である。特に、光学薄膜の分野においては、酸化膜や窒化膜などの薄膜を、反応性スパッタ装置を用いて成膜することが多いが、この場合の成膜速度や膜質はターゲットの表面状態に依存することが知られている。そして、ターゲットの表面状態は反応性ガスの分圧に関係している。通常、この成膜速度と反応性ガスの分圧とはヒステリシス曲線を描くような相関を有することが多く、また、投入電力においてもヒステリシス曲線が大きく異なるため不安定な状態であり、上記のようなスパッタ条件が変化し易くなっている。
【０００７】
【発明が解決しようとする課題】
そこで、多数の可動な膜厚補正板により膜厚補正部材を構成し、各膜厚補正板を駆動させてその開口部の形状を調整し、膜厚分布の変化に対応できるようにしたものとして、特開昭６１−１８３４６４号公報の第２図に示すものがある。しかしながら、このものでは、各膜厚補正板の駆動機構を作動させる際に、チャンバの真空度を維持できなくなる可能性があり、取扱い上効率的とは言えない。
【０００８】
さらに、上記の特開平４−１７３９７２号公報及び特開昭６１−１８３４６４号公報に開示されている従来技術は、ともに回転する基板上に成膜された薄膜の径方向の膜厚分布を補正するものであり、上記回転の開始及び終了時に生じる回転円周方向の膜厚分布を補正する効果については不明である。
【０００９】
上記問題点に鑑み、本発明は、種々のスパッタ条件の変動により生じる、薄膜の径方向の膜厚分布の変化や、円周方向の膜厚分布に対応して効率的に膜厚を補正し得る薄膜の成膜装置を提供し、さらに、その成膜装置を用いて薄膜を成膜する方法を提供することを課題とする。
【００１０】
【課題を介設するための手段】
上記課題を解決するため、本発明の薄膜の成膜装置は、互いに対向する回転基板と成膜源とを有する薄膜の成膜装置において、前記成膜源と対向する開口部を有し、前記基板と前記成膜源との間に設けられることによって前記成膜源から前記基板上に成膜される薄膜の成膜速度を規制する第１シャッタと、前記第１シャッタの開口部を覆うことによって前記開口部の面積を減少可能な、前記基板上に成膜される薄膜の膜厚を補正する前記第１シャッタに設けられた第２シャッタと、前記成膜源と前記基板との間に挿脱自在に設けられ、前記基板上の薄膜が所望膜厚に到達した時点で前記成膜源と前記基板との間に挿入されることによって前記基板上への薄膜の成膜を遮断する可動シャッタとを備えたことを特徴とする。
【００１１】
このものは、膜厚計測手段の計測値に応じて、第１シャッタに設けた第２シャッタ（開閉シャッタ）を作動させて、第１シャッタの開口部の開度（開口面積）を増減することにより、基板上の薄膜の成膜速度を調整でき、また、膜厚計測手段の計測値に応じて、可動シャッタを作動させて、基板上の成膜を遮断できる。したがって、第１シャッタとその第２シャッタとにより、回転基板の半径に沿って精度良く傾斜させて形成した径方向の膜厚分布を、可動シャッタにより所望膜厚に到達した成膜領域から順次成膜を遮断して、最後は、所望膜厚に揃えて平坦にしたものに補正することができる。このとき、第２シャッタを作動させて第１シャッタの開口部の開度を減少させることにより、薄膜の成膜速度が減少するので、基板上の薄膜の周方向の膜厚分布も平坦なものに補正されている。
【００１２】
また、このとき、回転基板の半径に沿った複数の測定点で前記薄膜の膜厚を計測することにより、薄膜の径方向及び周方向の膜厚分布を計測する際の感度が向上するだけでなく、回転基板の径方向に傾斜した膜厚分布を精度良く観測することができる。
【００１３】
これらの場合、成膜源をスパッタリングカソードで構成して、さらに、希ガスから成るスパッタガスと反応性ガスとを用いて、反応性スパッタリング法として誘電性薄膜を成膜することが可能となる。このような反応性ガスとしては、酸素、窒素、炭素、ケイ素等の元素を含むガスが考えられるが、目的に応じて、このような単体ガス（Ｏ₂、Ｏ₃、Ｎ₂等）や化合物ガス（Ｎ₂Ｏ、Ｈ₂Ｏ、ＮＨ₃等）のみならずこれらを混合して成る混合ガスを用いても良い。
【００１４】
そして、上記の成膜装置を用い、最初に、回転基板と成膜源との間に設けられた第１シャッタの開口部を成膜源と対向させ、その状態で、基板上に薄膜を所望膜厚のうちの所定割合の膜厚に成膜する第１工程と、膜厚計測手段による膜厚の計測で基板上の薄膜の膜厚が前記所定割合に達した時点で、第１シャッタに設けられた第２シャッタにより第１シャッタの開口部を覆って該開口部の開口面積を減少させた状態で基板上に薄膜の成膜を続行する第２工程と、膜厚計測手段による膜厚の計測で基板上の薄膜の膜厚が所望値に達した時点で、基板と成膜源との間に可動シャッタを挿入して基板上への薄膜の成膜を遮断する第３工程とをこの順で順次行うこととする。このような方法によれば、第１工程において、所望膜厚の大部分（最大膜厚部において９５％程度）を成膜した後、第２工程において、比較的遅い成膜速度で精度良く所望膜厚の成膜を達成すると共に周方向の膜厚分布を平坦なものに補正し、さらに、第３工程において、可動シャッタにより、所望膜厚に到達した基板上の成膜領域から成膜を遮断するので、径方向の膜厚分布は、最後には、所望膜厚に揃えて平坦にしたものに補正することができる。したがって、所望の均等な膜厚を得ることが可能である。
【００１５】
図３は、本発明に用いる反応性スパッタリング装置の概略を示す。図１の反応性スパッタリング装置と異なるのは、図１のシャッタ８の替りに、成膜速度規制部材である第１シャッタ１３ａと膜厚補正部材である第２シャッタ１４ａ、１４ｂとが設けられていること、基板ホルダ３の近傍に、平板形状の可動シャッタ１５が追加して設けられていること、酸化反応を促進するためのプラズマ源１６が追加して設けられていることである。
【００１６】
このうち、第１シャッタ１３ａと第２シャッタ１４ａ、１４ｂとを図４に上面図として示す。図４を参照して、第１シャッタ１３ａは、開口角度θの開口部１３ｂと、開口部１３ｃと、第２シャッタ１４ａ、１４ｂとを有し、図外の駆動機構が回転軸９と同軸の駆動歯車１４ｃを作動させると、第２シャッタ１４ａ、１４ｂにより第１シャッタ１３ａの開口部１３ｂの開度が増減できるように構成されている。
【００１７】
また、可動シャッタ１５は、基板４と平行な方向に可動であり、図外の作動機構によりスパッタリング装置１内に挿入されると、基板４とスパッタカソード６との間に介在し、スパッタリングによる基板４上の成膜を遮断できるように構成されている。
【００１８】
図３の成膜装置１により、ガラス基板４上に成膜を行うに際しては、まず、図１の場合と同様の前処理とプレスパッタとを行った後、ガス導入口１２ａからスパッタガスとしてＡｒガスを導入すると共に、ガス導入口１２ｂから反応性ガスとして酸素ガスを導入する。さらに、可動シャッタ１５を基板４の回転円外の充分離れた位置に待機させると共に第２シャッタ１４ａ、１４ｂの開度を充分に保った状態で、第１シャッタ１３ａを回転軸９まわりに回転させて、第１シャッタ１３ａの開口部１３ｂをターゲット５上に位置させる。そして、スパッタカソード６に電力を印加してスパッタカソード６上のＴｉターゲット５のスパッタリングを開始し、これにより、ＴｉＯ₂から成る酸化膜を基板４上に成膜する。このとき、基板ホルダ３は回転軸２まわりに回転しており、これに伴って基板４も回転されている。
【００１９】
なお、本実施の形態では、誘電性薄膜としてＴｉＯ₂から成る酸化膜を成膜するが、ガス導入口１２ｂから反応性ガスとして窒素ガスを導入すれば、窒化膜の形成も可能である。
【００２０】
上記のＴｉＯ₂から成る酸化膜の成膜に際しては、第１シャッタ１３ａが、回転基板４の半径に沿って回転円の外側に行くほど成膜速度が大きくなるような形状の開口部１３ｂを有するので、基板４上に成膜された薄膜の膜厚分布は、回転基板４の半径に沿って回転円の外側が内側より大きな膜厚を有するように傾斜したものとなる。
【００２１】
そして、基板４上のＴｉＯ_２の成膜を所定時間継続し、最も厚い部分の膜厚が所望膜厚のおおむね９５％程度になるまで成膜できたことを膜厚モニタ１０で計測した時点で、第１シャッタ１３ａの駆動歯車１４ｃにより第２シャッタ１４ａ、１４ｂの開度を減じ、第１シャッタ１３ａの開口部１３ｂを減少させる。このときに、第２シャッタ１４ａ、１４ｂの開度を減じ、第１シャッタ１３ａの開口部１３ｂを減少させたのは、開口面積を小さくして当初より成膜速度を遅くするためである。薄膜の膜厚に求められる厳密な均等性を実現するためには、成膜の開始及び終了の際にシャッタが開閉する瞬間の成膜の有無が円周方向の膜厚分布の平坦性に大きく影響するが、上記のように成膜途中に成膜速度を小さくするとこの影響が軽減でき、円周方向に平坦な膜厚分布が得られる。この意味において、成膜速度規制部材の第１シャッタ１３ａに設けられた開閉シャッタたる第２シャッタ１４ａ、１４ｂは、その開口部１３ｂの開口面積を変更できて、膜厚補正部材として機能している。また、このような方法による成膜速度の低下は、スパッタカソード６の印加電力を軽減することにより成膜速度を低下させる場合と異なり、ターゲット５の表面状態や反応性ガスの分圧などを変動させるものではないため、スパッタ条件自体に影響を与えるものではない。
【００２２】
一方、膜厚モニタ１０は、第１モニタ１０ａ₁-１０ｂ₁、第２モニタ１０ａ₂-１０ｂ₂、第３モニタ１０ａ₃-１０ｂ₃により、基板４上の薄膜の膜厚を３点の測定位置１０₁、１０₂、１０₃で計測しているが、この３点データを所定時間ごとに計測することにより、基板ホルダ３の回転円における径方向の薄膜の膜厚分布をモニタできる。なお、図３中、１０₁´、１０₂´、１０₃´は、基板４上の成膜領域において膜厚モニタ１０の測定位置１０₁、１０₂、１０₃のそれぞれに対応する同心円位置である。
【００２３】
そして、第２シャッタ１４ａ、１４ｂの開度を減少させた状態で、基板４上のＴｉＯ₂の成膜を所定時間継続し、膜厚モニタ１０の第１モニタ１０ａ₁-１０ｂ₁において、薄膜が所望膜厚に成膜したことを計測した時点で、可動シャッタ１５を移動して、測定位置に対応する同心円位置１０₁´と１０₂´との間の所定の位置までがこの可動シャッタ１５の先端部分１５ａに充分覆われるようにする。かくして、前記測定位置１０₁近傍における成膜が遮断されて終了する。
【００２４】
そして、そのまま、基板４上のＴｉＯ₂の成膜を所定時間継続し、膜厚モニタ１０の第２モニタ１０ａ₂-１０ｂ₂において、薄膜が所望膜厚に成膜したことを計測した時点で、可動シャッタ１５を移動して、測定位置に対応する同心円位置１０₂´と１０₃´との間の所定の位置までがこの可動シャッタ１５の先端部分１５ａに充分覆われるようにする。かくして、前記測定位置１０₂近傍における成膜が遮断されて終了する。
【００２５】
そして、そのままさらに、基板４上のＴｉＯ₂の成膜を所定時間継続し、膜厚モニタ１０の第３モニタ１０ａ₃-１０ｂ₃において、薄膜が所望膜厚に成膜できたことを計測した時点で、可動シャッタ１５を移動して、その先端部分１５ａを基板中心位置４ａに到達させ、基板４が可動シャッタ１５に完全に覆われるようにする。かくして、基板４上における成膜が遮断され、この時点で全成膜工程を終了する。
【００２６】
なお、本実施の形態では、回転基板４の半径に沿って回転円の外側に行くほど成膜速度が大きくなるような形状の開口部１３ｂを有する第１シャッタ１３ａを用い、回転基板４の半径に沿って回転円の外側が内側より大きな膜厚を有するように傾斜した膜厚分布を形成した。そして、このような径方向に傾斜した膜厚分布を、回転円の外側から内側へ可動シャッタ１５を移動させて、回転円の外側から内側へ順次成膜を遮断して、薄膜を所望膜厚に揃えて平坦な膜厚分布を得た。
【００２７】
しかしながら、本発明は、このような実施形態に限定されず、例えば、これとは逆に、回転基板４の半径に沿って回転円の内側が外側より大きな膜厚を有するように傾斜した膜厚分布を形成し、回転円の内側から外側へ順次成膜を遮断して、平坦な膜厚分布を得るようにすることも可能である。
【００２８】
また、膜厚モニタ１０の測定位置が多いほど、さらに精密な膜厚分布の制御が可能である。また、可動シャッタ１５はステップ状に移動するより、連続的に移動できるようにした方がさらに精密な膜厚分布制御が可能である。
【００２９】
【実施例】
[実施例]図３のスパッタ装置を用い、基板ホルダ３上に光学研磨した直径２００ｍｍのドーナツ状のガラス基板４を載置した後、チャンバ１内を１×１０^-5Ｐａ以下に真空排気した。ガス導入口１１からＡｒガスを２０ｓｃｃｍ、ガス導入口１２ｂから酸素ガスを５ｓｃｃｍでそれぞれ導入し、チャンバ１内を０．５Ｐａに保つ。可動シャッタ１５は、基板４上になく退避させた状態にして、第１シャッタ１３ａの開口部１３ｂ及び１３ｃがスパッタカソード６上に位置しないことを確認して基板ホルダ３を回転軸２まわりに１５００ｒｐｍで回転させた。スパッタカソード６に異常放電対策を考慮したパルスＤＣパワーを２ｋＷで印加して放電を開始した。このときのターゲット材質はＴｉである。
【００３０】
そして、第１シャッタ１３ａの開口部１３ｂをスパッタカソード６上に位置させ放電を開始した。また、Ｔｉの酸化反応を促進させるため、プラズマ源１６に６００Ｗの電力を導入しプラズマを発生させ、第１シャッタ１３ａの開口部１３ｃを介してプラズマが基板４の近傍に達するようにした。このときのＴｉＯ₂の成膜速度は、１５０Å／ｍｉｎである。そして、既に調整済みの光学式膜厚モニタ１０により最も外側の測定ポイント１０₁が１９９０Åの膜厚に達した時、図外の駆動機構により駆動歯車１４ｃを作動させて、成膜速度を規制する第２シャッタ１４ａ、１４ｂの開度を減少させ、第１シャッタ１３ａの開口部１３ｂの開口角度θに対し約１／１０の開口角度になった時点で、第２シャッタ１４ａ、１４ｂの開度減少作動を停止した。
【００３１】
この直前の基板４上の薄膜の膜厚は基板４の外周部の方が厚い傾向にあり、このときの第１モニタ１０ａ₁-１０ｂ₁、第２モニタ１０ａ₂-１０ｂ₂、第３モニタ１０ａ₃-１０ｂ₃により計測された膜厚値はそれぞれ１９９０Å、１９８０Å、１９６５Åであった。第２シャッタ１４ａ、１４ｂを作動して第１シャッタ１３ａの開口面積を減少させたときの成膜速度は１５Å／ｍｉｎであった。
【００３２】
そのまま、さらに薄膜の成膜を続行し、第１モニタ１０ａ₁-１０ｂ₁が２０００Åの膜厚を計測した瞬間に、可動シャッタ１５を移動させ、その先端部分１５ａが、第１モニタ１０ａ₁-１０ｂ₁の測定位置１０₁に対応する、基板４の成膜位置１０₁´を充分覆うようにして、回転基板４の外周部とこの成膜位置１０₁´近傍との領域において薄膜の成膜を遮断する。この結果、この成膜領域では、膜厚が２０００Åとなって成膜が終了する。このとき、第２モニタ１０ａ₂-１０ｂ₂及び第３モニタ１０ａ₃-１０ｂ₃が計測する膜厚値はそれぞれ１９８８Å及び１９７１Åであった。
【００３３】
そのまま、さらに薄膜の成膜を続行し、第２モニタ１０ａ₂-１０ｂ₂が２０００Åの膜厚を計測した瞬間に、可動シャッタ１５を移動させ、その先端部分１５ａが、第２モニタ１０ａ₂-１０ｂ₂の測定位置１０₂に対応する、基板４の成膜位置１０₂´を充分覆うようにして、回転基板４の外周部とこの成膜位置１０₂´近傍との領域において薄膜の成膜を遮断する。この結果、この成膜領域では、膜厚が２０００Åとなって成膜が終了する。このとき、第３モニタ１０ａ₃-１０ｂ₃が計測する膜厚値は１９８０Åであった。
【００３４】
そのまま、さらに、薄膜の成膜を続行し、第３モニタ１０ａ₃-１０ｂ₃が２０００Åの膜厚を計測した瞬間に、可動シャッタ１５を移動させ、その先端部分１５ａを基板中心位置４ａに到達させて、基板４を可動シャッタ１５で完全に覆い、基板４上の成膜を遮断する。この結果、基板４上では、膜厚が２０００Åに揃って成膜が終了する。
【００３５】
成膜終了後、基板４を取り出し、薄膜の膜厚と基板４上の膜厚分布とをエリプソメータで測定したところ、平均膜厚は２０００．０Åで、膜厚分布はこの膜厚に対して±０．０１％の優れた散布度を有するものであった。
【００３６】
［比較例］成膜速度を規制する第１シャッタ１３ａ及び第２シャッタ１４ａ、１４ｂ機構の替りにシャッタ板１７ａを用いた。図５を参照して、シャッタ板１７ａは、従来の装置において一般的に用いられている開口部１７ｂと、図４における開口部１３ｃと同形状の開口部１７ｃとを有している。この開口部１７ｃにより、［実施例］と同様の条件で、基板４の近傍にプラズマを到達させることができる。このシャッタ板１７ａを用いた以外は、［実施例］と同じく図３に示すスパッタ装置１を用いて同様の方法で薄膜の成膜を行った。得られた基板４を測定したところ、基板中心位置４ａからの距離が４０ｍｍの成膜位置では、その円周上での平均膜厚とその散布度とが２００７．２Å±１．３％として示される膜厚分布であった。また、基板中心位置４ａからの距離が８０ｍｍの成膜位置では、その円周上での平均膜厚とその散布度とが２００６．９Å±１．０％として示される膜厚分布であった。そして、基板全面では、平均膜厚とその散布度とが、２００７．１Å±１．８％として示される膜厚分布を有することが分かった。
【００３７】
【発明の効果】
以上の説明から明らかなように、本発明は、通常の成膜法により薄膜の所望膜厚の大部分を成膜した後、基板上に成膜される薄膜の膜厚と膜厚分布との計測結果に基づき、第２シャッタ（開閉シャッタ）を作動させ、第１シャッタの開口部の開度を調整して成膜速度を低下させた状態で、残りの膜厚部分を成膜し、さらに、基板上に成膜される薄膜の膜厚と膜厚分布との計測結果に基づき、可動シャッタを作動させ、所望の膜厚に到達した基板上の成膜領域の成膜を遮断できる。即ち、基板上では、所望の膜厚に到達した領域が出現した時点で、その成膜領域における成膜を終了させるので、基板上の全成膜領域で成膜が終了したとき、回転基板の径方向及び円周方向に良好な精度で均等な膜厚分布を有する薄膜を成膜できる。
【図面の簡単な説明】
【図１】従来の反応性スパッタリング装置の概要断面図
【図２】図１のシャッタ（成膜速度規制部材）の上面図
【図３】本発明の［実施例］において用いる反応性スパッタリング装置の概要断面図
【図４】図３の第１及び第２の両シャッタ（成膜速度規制部材）の上面図
【図５】［比較例］において用いるシャッタ板（成膜速度規制部材）の上面図
【符号の説明】
４回転基板
６スパッタカソード
８シャッタ（膜厚補正部材）８ａ開口部
１０膜厚モニタ
１０₁第１モニタの計測点
１０₂第２モニタの計測点
１０₃第３モニタの計測点
１３ａ第１シャッタ１３ｂ、１３ｃ開口部 θ 開口角度（開度）
１４ａ、１４ｂ第２シャッタ(開閉シャッタ）
１５可動シャッタ
１７ａシャッタ板１７ｂ、１７ｃ開口部[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an apparatus for forming a thin film on a rotating substrate and a method for forming a thin film using the apparatus. For example, when a film is formed on a glass substrate with a sputtering apparatus or the like, when a sputtered particle is deposited at a desired position on the substrate to form a thin film, the rotating substrate system used for the purpose of uniform film formation conditions is used. In the radial direction, a thin film having a film thickness distribution such that the substrate portion corresponding to the center of the target peaks is often formed. Further, in many cases, a film thickness distribution in which these portions are used as the start end or the end depends on which part of the rotating substrate starts and ends in the circumferential direction of the rotating substrate. In many cases, the spread degree of the film thickness is about several percent of the desired film thickness value. However, in the field of optical thin films used for optical elements, optical filters, etc. In order to control the film thickness (product of the film thickness and the refractive index), it is required to form a thin film having a strictly uniform film thickness.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, a sputtering apparatus that rotates a substrate in order to make the film forming conditions uniform and forms a thin film on the substrate has the configuration shown in FIG. In this apparatus, a substrate holder 3 that is rotatably supported by a rotation shaft 2 is provided above the apparatus chamber 1, and a glass substrate 4 is mounted on the holder 3. Further, a sputtering cathode 6 on which a Ti target 5 facing the direction of the substrate 4 is placed as a film forming source in one side region below the cross section of the apparatus chamber 1, and is composed of the Ti target 5 and the sputtering cathode 6. The deposition preventing plate 7 is provided outside the sputtering target. Furthermore, a shutter 8 having a circular opening 8 a is provided below the apparatus chamber 1 so as to be supported by a rotating shaft 9 and rotatable around the rotating shaft 9. (See Figure 2.)
[0003]
Here, in the sputtering apparatus of FIG. 1, the rotating shaft 2 of the substrate holder 3 and the rotating shaft 9 of the shutter 8 can be operated independently. The substrate holder 3 and the substrate 4 are provided with a film thickness monitor 10 for measuring the film thickness of the thin film formed on the substrate 4. Film thickness monitor 10 includes a light emitting portion 10a ₁ 10 A _3, consists emitting portion 10a ₁ 10 A correspond to the _third light receiving portion 10b ₁ ～10B ₃ Prefecture, in combination with the light receiving portion 10b and the light emitting portion 10a, the 1 monitor 10a _₁ -10b _1, constitutes a second monitor 10a ₂ -10B ₂ and the third monitor 10a _₃ -10b _3. In this way, by forming a plurality of monitors (first to third monitors) with the optical sensor including the light emitting units 10a _{1 to} 10a ₃ and the light receiving units 10b _{1 to} 10b ₃ , the film thickness monitor 10 is made of a glass substrate. By measuring the light transmittance between the thin film 4 and the thin film, the film thickness and distribution uniformity of the thin film can be monitored. The apparatus chamber 1 is configured to be evacuated by an exhaust pump 11, and further, a gas introduction port 12a is provided in a region on the sputtering target side below the section of the apparatus chamber 1, and a sputtering gas is introduced from the gas introduction port 12a. A gas inlet 12b is provided in the vicinity of the substrate holder 3 above the section of the apparatus chamber 1, and a reactive gas is introduced from the gas inlet 12b.
[0004]
When forming a film on the glass substrate 4, first, as a pretreatment, the inside of the chamber 1 is evacuated by an exhaust pump 11, Ar gas is then introduced as a sputter gas from the gas introduction port 12 a, and the shutter 8 is connected to the rotating shaft 9. It is adjusted so that the opening 8a is not positioned on the target 5 by rotating around. In this state, the surface of the target 5 is cleaned by pre-sputtering performed by applying power to the sputtering cathode 6. Thereafter, Ar gas is introduced as a sputtering gas from the gas introduction port 12a, oxygen gas is introduced as a reactive gas from the gas introduction port 12b, and the shutter 8 is rotated about the rotation axis 9 so that the opening 8a is the target. The Ti target 5 on the sputter cathode 6 is sputtered by adjusting the power so as to be positioned on the sputter cathode 6, thereby forming an oxide film made of TiO ₂ on the substrate 4. At this time, the substrate holder 3 is rotated around the rotation axis 2, and the substrate 4 is also rotated accordingly. Then, while the film thickness of the thin film formed on the substrate 4 is measured by the film thickness monitor 10, the film formation of TiO ₂ on the substrate 4 is continued for a predetermined time, and the thin film can be formed to the predetermined film thickness. Then, the shutter 8 is rotated again so that the opening 8a is not positioned on the target 5, and the film formation is finished in this state.
[0005]
In the above-described conventional apparatus, the shutter 8 is used as a means for switching the start and end of film formation or as a means for preventing the target material from flying to the substrate 4 during pre-sputtering. It also has a function of correcting the film thickness distribution of the thin film on the substrate 4 by the shape of the portion 8a. As a sputtering apparatus having a shutter (thickness correction plate) having an opening having a shape that enables film thickness correction in this way, a shutter having the shape of the opening shown in FIG. 5 of Japanese Patent Laid-Open No. 4-173972 ( What is provided with a film thickness correction board) is disclosed.
[0006]
However, in the shutter (thickness correction plate) having an opening having a fixed shape in this way, various sputtering conditions (vacuum degree, gas introduction amount, gas discharge amount from the chamber, sputtering voltage, sputtering voltage, etc.) during sputtering. It is difficult to cope with changes in current and the like. In particular, in the field of optical thin films, thin films such as oxide films and nitride films are often formed using a reactive sputtering apparatus. In this case, the film formation speed and film quality depend on the surface condition of the target. It is known. The surface state of the target is related to the partial pressure of the reactive gas. In general, the deposition rate and the partial pressure of the reactive gas often have a correlation that draws a hysteresis curve, and the hysteresis curve also varies greatly in the applied power, which is an unstable state. The sputter conditions are likely to change.
[0007]
[Problems to be solved by the invention]
Therefore, it is assumed that a film thickness correcting member is constituted by a large number of movable film thickness correcting plates, and each film thickness correcting plate is driven to adjust the shape of the opening to cope with the change in the film thickness distribution. FIG. 2 of Japanese Patent Application Laid-Open No. 61-183464. However, in this case, when operating the drive mechanism of each film thickness correction plate, there is a possibility that the degree of vacuum of the chamber cannot be maintained, and it cannot be said that it is efficient in handling.
[0008]
Furthermore, the prior art disclosed in the above Japanese Patent Laid-Open Nos. 4-173972 and 61-183464 corrects the film thickness distribution in the radial direction of the thin film formed on the rotating substrate. The effect of correcting the film thickness distribution in the rotational circumferential direction that occurs at the start and end of the rotation is unclear.
[0009]
In view of the above problems, the present invention efficiently corrects the film thickness in response to changes in the film thickness distribution in the radial direction of the thin film and the film thickness distribution in the circumferential direction caused by variations in various sputtering conditions. An object of the present invention is to provide a thin film forming apparatus to be obtained, and to provide a method of forming a thin film using the film forming apparatus.
[0010]
[Means for interposing problems]
In order to solve the above problems, a thin film deposition apparatus of the present invention is a thin film deposition apparatus having a rotating substrate and a deposition source facing each other, and has an opening facing the deposition source, A first shutter that is provided between the substrate and the film forming source to regulate a film forming speed of a thin film formed on the substrate from the film forming source, and covers an opening of the first shutter. The area of the opening can be reduced by the second shutter provided in the first shutter for correcting the film thickness of the thin film formed on the substrate, and between the film formation source and the substrate. A movable device that is detachably provided and is inserted between the film forming source and the substrate when the thin film on the substrate reaches a desired film thickness, thereby blocking the film formation on the substrate. characterized in that a shutter.
[0011]
According to this, the second shutter (opening / closing shutter) provided in the first shutter is operated according to the measurement value of the film thickness measuring means, and the opening degree (opening area) of the opening portion of the first shutter is increased or decreased. Thus, the film formation speed of the thin film on the substrate can be adjusted, and the film formation on the substrate can be blocked by operating the movable shutter in accordance with the measurement value of the film thickness measurement means. Accordingly, the radial film thickness distribution formed by the first shutter and the second shutter with high accuracy along the radius of the rotating substrate is sequentially formed from the film formation region that has reached the desired film thickness by the movable shutter. The film can be cut off and finally corrected to be flat to the desired film thickness. At this time, by operating the second shutter to reduce the opening degree of the opening of the first shutter , the film forming speed of the thin film is reduced, so that the film thickness distribution in the circumferential direction of the thin film on the substrate is also flat. It has been corrected.
[0012]
In addition, at this time, by measuring the film thickness of the thin film at a plurality of measurement points along the radius of the rotating substrate, only the sensitivity when measuring the film thickness distribution in the radial direction and the circumferential direction of the thin film is improved. In addition, the film thickness distribution inclined in the radial direction of the rotating substrate can be accurately observed.
[0013]
In these cases, it is possible to form a dielectric thin film as a reactive sputtering method by using a sputtering cathode as a film forming source and further using a sputtering gas composed of a rare gas and a reactive gas. As such a reactive gas, a gas containing an element such as oxygen, nitrogen, carbon, or silicon can be considered. Depending on the purpose, such a simple gas (O ₂ , O ₃ , N _2, etc.) or a compound may be used. gas _{_{(N 2 O, H 2 O}} , NH 3 , etc.) not only can be used a mixed gas obtained by mixing them.
[0014]
Then, using the film forming apparatus, first, the opening of the first shutter provided between the rotating substrate and the film forming source is opposed to the film forming source, and in this state, a thin film is desired on the substrate. When the film thickness of the thin film on the substrate reaches the predetermined ratio in the first step of forming the film at a predetermined ratio of the film thickness and the film thickness measurement by the film thickness measuring means, the first shutter is applied. a second step of continuing the deposition of a thin film on a substrate in a provided a second state in which it covers the opening portion of the first shutter to reduce the opening area of the opening by the shutter, the film thickness by the film thickness measuring device When the film thickness of the thin film on the substrate reaches a desired value in the measurement of step 3 , a movable shutter is inserted between the substrate and the film formation source and a third step of blocking film formation on the substrate is performed. It will be performed sequentially in this order. According to such a method, in the first step, after a large part of the desired film thickness (about 95% in the maximum film thickness portion) is formed, the desired value is accurately obtained at a relatively low film formation speed in the second step. At the same time, the film thickness distribution in the circumferential direction is corrected to a flat one, and in the third step, the film is formed from the film formation region on the substrate that has reached the desired film thickness by the movable shutter. Since the blocking is performed, the film thickness distribution in the radial direction can be corrected to a flat film finally with a desired film thickness. Therefore, a desired uniform film thickness can be obtained.
[0015]
FIG. 3 shows an outline of the reactive sputtering apparatus used in the present invention. The reactive sputtering apparatus of FIG. 1 is different from the shutter 8 of FIG. 1 in that a first shutter 13a that is a film forming speed regulating member and second shutters 14a and 14b that are film thickness correcting members are provided. being in the vicinity of the substrate holder 3, the movable shutter 15 of the flat plate is provided in addition, is that a plasma source 16 for accelerating the oxidation reaction are additionally provided.
[0016]
Among these, the first shutter 13a and the second shutters 14a and 14b are shown as a top view in FIG. Referring to FIG. 4, the first shutter 13 a has an opening 13 b having an opening angle θ, an opening 13 c, and second shutters 14 a and 14 b, and a drive mechanism (not shown) is coaxial with the rotary shaft 9. When the drive gear 14c is operated, the opening degree of the opening 13b of the first shutter 13a can be increased or decreased by the second shutters 14a and 14b.
[0017]
The movable shutter 15 is movable in a direction parallel to the substrate 4 and is inserted between the substrate 4 and the sputter cathode 6 when inserted into the sputtering apparatus 1 by an operating mechanism (not shown). 4 is configured to be able to block the film formation on 4.
[0018]
When performing film formation on the glass substrate 4 by the film forming apparatus 1 in FIG. 3, first, pre-processing and pre-sputtering similar to those in FIG. 1 are performed, and then Ar is sputtered from the gas inlet 12a. While introducing gas, oxygen gas is introduce | transduced as reactive gas from the gas inlet 12b. Further, the first shutter 13a is rotated around the rotation shaft 9 while the movable shutter 15 is kept at a position sufficiently away from the rotation circle of the substrate 4 and the opening degree of the second shutters 14a and 14b is sufficiently maintained. Thus, the opening 13b of the first shutter 13a is positioned on the target 5. Then, power is applied to the sputtering cathode 6 to start sputtering of the Ti target 5 on the sputtering cathode 6, thereby forming an oxide film made of TiO ₂ on the substrate 4. At this time, the substrate holder 3 is rotated around the rotation axis 2, and the substrate 4 is also rotated accordingly.
[0019]
In this embodiment, an oxide film made of TiO ₂ is formed as the dielectric thin film. However, if nitrogen gas is introduced as the reactive gas from the gas inlet 12b, a nitride film can be formed.
[0020]
When forming the oxide film made of TiO ₂ , the first shutter 13a has an opening 13b having a shape such that the film forming speed increases toward the outside of the rotating circle along the radius of the rotating substrate 4. Therefore, the film thickness distribution of the thin film formed on the substrate 4 is inclined so that the outer side of the rotating circle has a larger film thickness than the inner side along the radius of the rotating substrate 4.
[0021]
At the time when the film thickness monitor 10 measured that the film formation of TiO ₂ on the substrate 4 was continued for a predetermined time and the film thickness of the thickest part was about 95% of the desired film thickness. The opening of the second shutter 14a, 14b is reduced by the drive gear 14c of the first shutter 13a, and the opening 13b of the first shutter 13a is reduced. At this time, the reason why the opening degree of the second shutters 14a and 14b is reduced and the opening part 13b of the first shutter 13a is reduced is to reduce the opening area and to reduce the film formation rate from the beginning. In order to achieve the strict uniformity required for the thickness of the thin film, the presence or absence of film formation at the moment when the shutter opens and closes at the start and end of film formation greatly increases the flatness of the film thickness distribution in the circumferential direction. However, if the film formation rate is reduced during film formation as described above, this influence can be reduced, and a flat film thickness distribution in the circumferential direction can be obtained. In this sense, the second shutters 14a and 14b, which are open / close shutters, provided on the first shutter 13a of the film formation speed regulating member can change the opening area of the opening 13b and function as a film thickness correction member . . Further, the decrease in the film formation rate by such a method is different from the case in which the film formation rate is decreased by reducing the power applied to the sputter cathode 6, and the surface state of the target 5 and the partial pressure of the reactive gas are changed. Therefore, the sputtering conditions themselves are not affected.
[0022]
On the other hand, the film thickness monitor 10 measures the film thickness of the thin film on the substrate 4 at three points by the first monitor 10a ₁ -10b ₁ , the second monitor 10a ₂ -10b ₂ , and the third monitor 10a ₃ -10b _3. Although the measurement is performed at 10 ₁ , 10 ₂ , and 10 ₃ , the thickness distribution of the thin film in the radial direction in the rotation circle of the substrate holder 3 can be monitored by measuring the three-point data at predetermined time intervals. In FIG. 3, 10 ₁ ′, 10 ₂ ′, 10 ₃ ′ are concentric positions corresponding to the measurement positions 10 ₁ , 10 ₂ , 10 ₃ of the film thickness monitor 10 in the film formation region on the substrate 4. is there.
[0023]
Then, the film formation of TiO ₂ on the substrate 4 is continued for a predetermined time in a state where the opening degree of the second shutters 14 a and 14 b is decreased, and the thin film is formed in the first monitors 10 a _{1 to} 10 b ₁ of the film thickness monitor 10. When it is measured that the film has been formed to have a desired film thickness, the movable shutter 15 is moved to a predetermined position between the concentric positions 10 ₁ ′ and 10 ₂ ′ corresponding to the measurement position. The tip portion 15a is sufficiently covered. Thus, film formation at the measurement position 10 ₁ near the ends are cut off.
[0024]
Then, the film formation of TiO ₂ on the substrate 4 is continued for a predetermined time, and at the time when the second monitor 10a ₂ -10b ₂ of the film thickness monitor 10 measures that the thin film has been formed to the desired film thickness, The movable shutter 15 is moved so that the tip portion 15a of the movable shutter 15 is sufficiently covered up to a predetermined position between the concentric positions 10 ₂ ′ and 10 ₃ ′ corresponding to the measurement position. Thus, film formation at the measurement position 10 ₂ near ends blocked.
[0025]
Then, the film formation of TiO ₂ on the substrate 4 is further continued for a predetermined time, and when the third monitor 10a ₃ -10b ₃ of the film thickness monitor 10 measures that the thin film has been formed to the desired film thickness. Thus, the movable shutter 15 is moved so that the front end portion 15a reaches the substrate center position 4a so that the substrate 4 is completely covered by the movable shutter 15. Thus, the film formation on the substrate 4 is blocked, and at this point, the entire film formation process is completed.
[0026]
In the present embodiment, the first shutter 13a having the opening 13b having a shape in which the film forming speed increases toward the outside of the rotation circle along the radius of the rotation substrate 4 is used. A film thickness distribution that is inclined so that the outer side of the rotating circle has a larger film thickness than the inner side is formed. The film thickness distribution inclined in the radial direction is moved from the outer side to the inner side of the rotating circle to move the movable shutter 15 so that the film formation is sequentially interrupted from the outer side to the inner side of the rotating circle. A flat film thickness distribution was obtained.
[0027]
However, the present invention is not limited to such an embodiment. For example, on the contrary, the film thickness is inclined so that the inner side of the rotating circle has a larger film thickness than the outer side along the radius of the rotating substrate 4. It is also possible to form a distribution and sequentially block the film formation from the inside to the outside of the rotating circle to obtain a flat film thickness distribution.
[0028]
Further, the more the measurement positions of the film thickness monitor 10, the more precise control of the film thickness distribution is possible. Further, it is possible to control the film thickness distribution more precisely by allowing the movable shutter 15 to move continuously rather than moving in a stepped manner.
[0029]
【Example】
[Embodiment] Using a sputtering apparatus of FIG. 3, a glass substrate 4 having a diameter of 200 mm that was optically polished was placed on the substrate holder 3, and then the inside of the chamber 1 was evacuated to 1 × 10 ⁻⁵ Pa or less. . Ar gas is introduced at 20 sccm from the gas inlet 11 and oxygen gas is introduced at 5 sccm from the gas inlet 12 b, and the inside of the chamber 1 is maintained at 0.5 Pa. The movable shutter 15 is retracted without being on the substrate 4, and it is confirmed that the openings 13 b and 13 c of the first shutter 13 a are not located on the sputter cathode 6, and the substrate holder 3 is rotated about 1500 rpm around the rotation axis 2. It was rotated with. Discharge was started by applying a pulse DC power of 2 kW in consideration of abnormal discharge countermeasures to the sputter cathode 6. The target material at this time is Ti.
[0030]
Then, the opening 13b of the first shutter 13a was positioned on the sputter cathode 6 to start discharging. In order to promote the oxidation reaction of Ti, 600 W of electric power was introduced into the plasma source 16 to generate plasma, so that the plasma reached the vicinity of the substrate 4 through the opening 13c of the first shutter 13a. At this time, the deposition rate of TiO ₂ is 150 Å / min. Then, the outermost measurement points 10 ₁ by previously adjusted optical film thickness monitor 10 when reaching the film thickness of 1990A, actuates the drive gear 14c by an unshown driving mechanism, to regulate the deposition rate When the opening degree of the second shutters 14a and 14b is decreased, and the opening angle θ of the opening part 13b of the first shutter 13a reaches about 1/10, the opening degree of the second shutters 14a and 14b decreases. The operation was stopped.
[0031]
The film thickness of the thin film on the substrate 4 immediately before this tends to be thicker in the outer peripheral portion of the substrate 4, and at this time, the first monitor 10a ₁ -10b ₁ , the second monitor 10a ₂ -10b ₂ , the third monitor 10a _The film thickness values measured by 3-10b ₃ were 1990 mm, 1980 mm, and 1965 mm, respectively. When the second shutters 14a and 14b were operated to reduce the opening area of the first shutter 13a, the film formation rate was 15 Å / min.
[0032]
The film formation is further continued as it is, and at the moment when the first monitor 10a ₁ -10b ₁ measures the film thickness of 2000 mm, the movable shutter 15 is moved, and the tip portion 15a thereof is the first monitor 10a ₁ -10b. _A thin film is formed in a region between the outer peripheral portion of the rotating substrate 4 and the vicinity of the film forming position 10 ₁ ′ so as to sufficiently cover the film forming position 10 ₁ ′ corresponding to the measurement position 10 ₁ of _1. Cut off. As a result, in this film formation region, the film thickness is 2000 mm and the film formation is completed. At this time, the film thickness values measured by the second monitor 10a ₂ -10b ₂ and the third monitor 10a ₃ -10b ₃ were 1988 mm and 1971 mm, respectively.
[0033]
The film formation is further continued as it is, and at the moment when the second monitor 10a ₂ -10b ₂ measures the film thickness of 2000 mm, the movable shutter 15 is moved, and the tip portion 15a thereof is moved to the second monitor 10a ₂ -10b. _The thin film is formed in the region between the outer peripheral portion of the rotating substrate 4 and the vicinity of the film forming position 10 ₂ ′ so as to sufficiently cover the film forming position 10 ₂ ′ of the substrate 4 corresponding to the _second measurement position 10 _2. Cut off. As a result, in this film formation region, the film thickness is 2000 mm and the film formation is completed. At this time, the film thickness value measured by the third monitor 10a ₃ -10b ₃ was 1980 mm.
[0034]
The thin film deposition is continued as it is, and at the moment when the third monitor 10a ₃ -10b ₃ measures the film thickness of 2000 mm, the movable shutter 15 is moved so that the tip portion 15a reaches the substrate center position 4a. Then, the substrate 4 is completely covered with the movable shutter 15 to block the film formation on the substrate 4. As a result, the film formation is completed on the substrate 4 with a film thickness of 2000 mm.
[0035]
After the film formation was completed, the substrate 4 was taken out and the film thickness of the thin film and the film thickness distribution on the substrate 4 were measured with an ellipsometer. The average film thickness was 2000.0 mm, and the film thickness distribution was ±± It had an excellent spreading degree of 0.01%.
[0036]
[Comparative Example] A shutter plate 17a was used in place of the first shutter 13a and the second shutters 14a and 14b which regulate the film forming speed. Referring to FIG. 5, shutter plate 17a has an opening 17b generally used in a conventional apparatus and an opening 17c having the same shape as opening 13c in FIG. This opening 17c allows plasma to reach the vicinity of the substrate 4 under the same conditions as in the [Example]. A thin film was formed by the same method using the sputtering apparatus 1 shown in FIG. 3 as in Example, except that this shutter plate 17a was used. When the obtained substrate 4 was measured, the average film thickness on the circumference and the degree of dispersion were shown as 2007.2Å ± 1.3% at the film formation position where the distance from the substrate center position 4a was 40 mm. Film thickness distribution. In addition, at the film forming position where the distance from the substrate center position 4a is 80 mm, the film thickness distribution shows the average film thickness on the circumference and the degree of dispersion as 2006.9６ ± 1.0%. And it turned out that it has a film thickness distribution shown as an average film thickness and its dispersion | spreading degree as 2007.1 ± 1.8% in the whole substrate surface.
[0037]
【The invention's effect】
As is apparent from the above description, the present invention provides a relationship between the film thickness and the film thickness distribution of the thin film formed on the substrate after forming a large portion of the desired film thickness by a normal film forming method. Based on the measurement result, the second shutter (opening / closing shutter) is operated, the opening of the opening of the first shutter is adjusted, and the film forming speed is reduced, and the remaining film thickness portion is further formed. Based on the measurement results of the film thickness and the film thickness distribution of the thin film formed on the substrate, the movable shutter can be operated to block the film formation in the film formation region on the substrate that has reached the desired film thickness. That is, when a region having reached a desired film thickness appears on the substrate, the film formation in the film formation region is terminated, so when the film formation is completed in all the film formation regions on the substrate, A thin film having a uniform film thickness distribution can be formed with good accuracy in the radial direction and the circumferential direction.
[Brief description of the drawings]
1 is a schematic cross-sectional view of a conventional reactive sputtering apparatus. FIG. 2 is a top view of a shutter (film formation rate regulating member) in FIG. 1. FIG. 3 is a schematic view of a reactive sputtering apparatus used in [Example] of the present invention. FIG. 4 is a top sectional view of the first and second shutters (film formation rate regulating member) in FIG. 3. FIG. 5 is a top view of a shutter plate (film formation rate regulating member) used in [Comparative Example]. [Explanation of symbols]
4 Rotating Substrate 6 Sputter Cathode 8 Shutter (Film Thickness Correction Member) 8a Opening 10 Film Thickness Monitor 10 ₁ First Monitor Measurement Point 10 ₂ Second Monitor Measurement Point 10 ₃ Third Monitor Measurement Point 13a First Shutter 13b , 13c Opening θ Opening angle (opening)
14a, 14b Second shutter (open / close shutter)
15 Movable shutter 17a Shutter plate 17b, 17c Opening

Claims

In a thin film forming apparatus having a rotating substrate and a film forming source facing each other, the film forming device has an opening facing the film forming source and is provided between the substrate and the film forming source. A first shutter that regulates a deposition rate of a thin film formed on the substrate from a source ; and a film formation on the substrate that can reduce an area of the opening by covering the opening of the first shutter A second shutter provided in the first shutter for correcting the thickness of the thin film to be formed, and a film formed on the substrate so as to be detachable between the film forming source and the substrate. film forming apparatus of thin film characterized in that a movable shutter for blocking the deposition of thin films on the substrate by being inserted between the substrate and the deposition source at a time when the arrived.

2. The thin film formation according to claim 1, wherein the film forming source is formed of a sputtering cathode, and the dielectric thin film is formed by a reactive sputtering method using a sputtering gas composed of a rare gas and a reactive gas. Membrane device.

In a method of forming a thin film on a substrate having a rotating substrate and a film forming source facing each other, an opening of a first shutter provided between the substrate and the film forming source is used as the film forming source. In this state, the first step of forming a thin film on the substrate at a predetermined proportion of the desired film thickness, and the measurement of the film thickness by the film thickness measuring means, When the film thickness reaches the predetermined ratio, the second shutter provided on the first shutter covers the opening of the first shutter and reduces the opening area of the opening on the substrate. When the film thickness of the thin film on the substrate reaches the desired value in the second step of continuing film deposition and the film thickness measurement by the film thickness measuring means, the substrate and the film deposition source insert the movable shutter between and a third step of interrupting the deposition of thin films on the substrate Method of forming a thin film characterized and.