JP3543672B2 - Sample surface treatment equipment using plasma - Google Patents

Description

【００１０】
【表２】

【００１１】
【表３】

【００１２】
表１〜表３の記載内容から把握されるように、上記の公報に開示されている装置は、
（１）安定なグロー放電を得ることを目的として、成膜を行なうための原料ガスをＨｅで大量に希釈する、
（２）大面積に均一な成膜を行なうために、高抵抗体２４４を、電極２４２及び２４３の少なくとも一方に取り付けることにより、直流電流が流れずに交流電流のみが流れるようにして、単位面積当たりの電流密度を制限してプラズマ２４０ｐが均一に広がりやすくする、
（３）表２に示した実験結果より、試料基板２４５と高抵抗体２４４との間の距離２４０ｇが小さいほど、膜厚分布の小さい均一な膜が形成されるので、膜厚分布を均一にするために、試料基板２４５と高抵抗体２４４との間の距離２４０ｇを１０ｍｍ〜０．１ｍｍに設定する、及び
（４）表３に示した実験結果より、全ガス流量Ｑを放電空間の体積Ｓで割った値Ｑ／Ｓが１０^−１ｓｅｃ^−１のときには、供給された原料ガスがすぐに分解してしまうために基板２４５上の成膜速度が低下し、一方、値Ｑ／Ｓが大きいと供給ガスがプラズマ２４０ｐを直ちに通過するために分解されず、成膜速度を低下させ且つ原料ガスが有効に使用されないので、放電空間のガスが、１０^−２ｓｅｃ〜１ｓｅｃで置換されるように、上記のＱ／Ｓが、１ｓｅｃ^−１〜１０^２ｓｅｃ^−１となるように成膜用の原料ガスとＨｅとからなる混合ガスを放電空間に供給する、
という特徴をもつ。
【００１３】
【発明が解決しようとする課題】
しかし、上記の従来技術は、以下の様な問題点を有する。
【００１４】
すなわち、成膜用原料ガスとＨｅとの混合ガスによって成膜室２４１の全体を大気圧周近傍の高圧力雰囲気で充たして高圧プラズマ２４０ｐを発生させ、成膜用原料ガスを分解して試料基板２４５の上に成膜を行なうので、プラズマ２４０ｐの中で発生した反応生成物が、プラズマ２４０ｐの外部に拡散後、雰囲気気体中を長時間浮遊・凝縮する。これによって、反応生成物の粒径の増大、及び、このように粒径が増大した反応生成物の粒子数の増加が発生する。粒径が増大した反応生成物が成膜基板２４５の表面に再付着すると、膜中に粒子状生成物が混入して膜質を低下させ、また反応容器の内壁に付着することにより、プロセス自体の歩留りを悪化させる。
【００１５】
また、成膜室内を大気圧近傍の高圧力に充填させるために、ガス漏洩時に成膜室の外に漏洩するガスのモル数が多く、装置の安全性が低い。
【００１６】
更に、試料基板２４５の搬出時の反応ガスパージの際に、反応ガスの排気に時間がかかる。このため、成膜速度は早いものの、成膜装置全体のスループットが低い。
【００１７】
上記の３つの問題点は何れも、反応容器全体を高圧力雰囲気に充填させることに起因する。
【００１８】
更に、電極間ギャップ２４０ｇを小さくすると、多孔板高抵抗体２４４の穴より噴出した反応ガス流が試料基板２４５の表面に衝突し、噴出穴の直下が周囲とは異なった成膜量分布を呈して、試料基板２４５の表面におけるの膜の均一性を悪化させる。
【００１９】
電極間ギャップ２４０ｇを小さくする場合、試料基板２４５に対する非接地電極２４２の傾きにより、反応ガスの流量分布が変化し、膜均一性を悪化させる。
【００２０】
拡散し難い高圧プラズマ２４０ｐを電力負荷した非接地電極２４２と試料基板２４５を設置した接地電極２４３との間で発生させるために、高圧プラズマ２４０ｐが試料基板２４５の全体に発生し難く、大面積試料基板の全体に均一に成膜することが困難である。また、試料基板２４５より小さい領域にプラズマ２４０ｐを発生させて、非接地電極２４２と試料基板２４５とを相対移動させて基板２４５の表面全体を成膜する場合においても、電極２４２或いは基板２４５の移動により電力供給路の等価回路が変化するために、成膜量分布を発生して膜均一性を悪化させる。
【００２１】
以下では、上記のような従来技術の問題点のうちで、特に第１に説明した粒径の大きな反応生成物の形成・付着に関連する点、及び第４に説明した多孔板高抵抗体２４４の噴出穴の直下における成膜量分布の変化について、更に説明する。
【００２２】
まず、成膜室２４１の内部を大気圧近傍に充填することによる膜質の劣化及びプロセス歩留り低下の原理について、説明する。
【００２３】
供給された原料ガスは、大気圧プラズマ２４０ｐの中で分解された後に成膜基板２４５に到達し、成膜基板２４５上に膜を形成する。ここで、プラズマ２４０ｐ中においては、原料ガスの分解・解離反応のみでなく、重合・凝縮反応も同時に起こる。このため、成膜室２４１内部に混入した不純物と原料ガス原子とからなる粉状の反応生成物も多数存在して、これらの反応生成物も、基板２４５の表面に到達する。ここで、プラズマ中で凝縮した反応生成物は、プラズマ２４０ｐによって即座に再分解されるので、基板２４５の表面に到達しない。しかし、プラズマ２４０ｐの外部に放出された反応生成物は、再分解されることがなく、むしろ、互いに或いは反応容器２４２の中の不純物と凝縮して、その粒径を増大させる。また、これに伴って、このような粒径の大きい反応生成物の粒子数も、増大する。ここで問題となるのは、粒径の大きな反応生成物であり、これらは、再びプラズマ２４０ｐの中へ拡散した場合においても即座に再分解されず、試料基板２４５に到達して、基板２４５上に形成された膜中に混入し、膜質を著しく低下させる。更に、これらの粒径の大きな反応生成物は、成膜室２４１の内壁に付着して成膜室２４１の内部を汚染し、その結果として成膜後の膜表面を汚染して、プロセス自体の歩留りを悪化させる。
【００２４】
ここで問題となるのは、前述の従来技術は大気圧近傍の高圧力に成膜室２４１の内部を充填させるために、プラズマ２４０ｐの外部においても、プラズマ２４０ｐの内部と同等の圧力状態であることである。この様な場合、成膜室２４１の内の雰囲気圧力を低下させて、プラズマ２４０ｐの外部における反応生成物の粒径及び粒子数の増大を抑制することも考えられるが、その場合には、同時にプラズマ２４０ｐの圧力も低下して成膜速度を低下させ、更にはプロセスのスループットを悪化させる。
このように、前述の従来技術では、大気圧近傍において成膜を行なうと膜質が劣化し、或いは、圧力を低下させて成膜を行なうと高速成膜が実現できない。これは、前述の従来技術自体が、原理的に成膜室２４１内を大気圧近傍の圧力に充填してプラズマ２４０ｐを発生させることによって成膜を行う方法である点に起因する。
【００２５】
次に、多孔板高抵抗体２４４の供給口直下において成膜を行なう場合に発生する膜厚分布について、図２５を参照しながら説明する。
【００２６】
図２５は、反応ガス供給口２５０の直下に形成される薄膜２５２の膜厚分布を示す概略図である。図中で、２５０はガス供給口、２５１は試料基板に衝突する反応ガスの流れ、２５２は不図示の基板上に形成される薄膜、２５３は、反応ガス供給口２５０の直下に形成される薄膜２５２の凸部である。
【００２７】
図２４の従来技術の構成では、非接地電極２４２と試料基板２４５との間に大気圧近傍のプラズマ２４０ｐを発生させ、プラズマ領域中に多数のガス供給口２５０より原料ガスを含んだＨｅ混合気体を噴出させる。例えば、電極２４２及び２４３の間隔は１０ｍｍ以下で０．１ｍｍ以上と記載されている。
【００２８】
しかし、電極２４２及び２４３の間隔が狭い場合は、ガス供給口２５０より噴出した反応ガスの流れ２５１は、ガス供給口２５０の直下の試料基板表面に垂直に衝突するので、この箇所に効率よく反応ガスが供給されることになり、結果として、ガス供給口２５０の直下がその周辺より成膜量が多くなり、図２５に示されるような凸部（不均一な膜厚分布）２５３を形成する。
【００２９】
従って、図２４に示された従来技術では、電極２４２と試料基板２４５との間のギャップは、上記のような不均一な膜厚分布２５３の発生を抑制するためには狭くできない。これは、電極２４２及び試料基板２４５の間にプラズマ２４０ｐを発生させて、プラズマ発生部分に反応ガス供給口２５０を設置するという構成に起因する。
【００３０】
上記では、従来技術により試料基板２４５に成膜を行う場合を例にとってその課題を説明してきたが、表面改質を行なう場合においても同様の問題点が存在する。
【００３１】
本発明は、上記の課題を解決するためになされたものであり、その目的は、（１）試料表面に高能率に成膜或いは表面改質を行ない、且つ清浄雰囲気下において試料表面に反応生成物が再付着することなく、良質な膜形成或いは表面改質を行なうことができる、プラズマを用いた表面処理方法及び表面処理装置を提供すること、（２）所望の気体雰囲気圧力を少なくともプラズマ発生部より低圧に或いは真空に維持することによって、反応生成物の凝縮や、反応ガス噴出領域直下の成膜量或いは処理層厚さの不均一な分布を発生させずに、大面積試料の上に均一に成膜或いは表面改質を行なうことのできる、プラズマを用いた表面処理方法及び表面処理装置を提供すること、である。
【００３２】
【課題を解決するための手段】
本発明によるプラズマを用いた試料の表面処理装置は、所定の気体雰囲気内に配置されており、表面処理される試料が載置される試料台と、該試料の被処理面の形状の相似形状を少なくとも一部に有する壁面が該試料の被処理面に対向して設けられた電極と、該試料の被処理面に局所的に反応ガスを供給するように該電極の壁面に設けられた反応ガス供給口と、該電極に電力を印加する電源と、前記壁面における前記反応ガス供給口から離れた位置に開放端を有し、該電極に印加される電力を該開放端まで伝送するように該電極内に設けられた電力伝送線路とを備え、該電極の壁面は、該試料の被処理面に近接して設けられており、該試料の被処理面との間に、該反応ガス供給口から該気体雰囲気に向けて低コンダクタンスの気体流路を形成するとともに、該気体雰囲気の圧力と該反応ガス供給口から供給される反応ガスの圧力との差圧によって該気体雰囲気よりも高い圧力を有する高圧反応ガス領域を該低コンダクタンスの気体流路における該開放端の近傍に局所的に形成し、該開放端に伝送される電力によって高電界を発生させて、該反応ガスに基づく局所的な高圧プラズマを該高圧反応ガス領域に発生させることにより、該高圧プラズマ中の反応ガスの反応種によって該試料に対する表面処理が行われ、そのことによって、上記の目的が達成される。
また、本発明によるプラズマを用いた試料の表面処理装置は、所定の気体雰囲気内に配置された試料の被処理面の形状の相似形状を少なくとも一部に有する壁面が該試料の被処理面に対向して設けられた電極と、該試料の被処理面に局所的に反応ガスを供給するように該電極の壁面に設けられた反応ガス供給口と、該電極に電力を印加する電源とを備え、該試料及び該電極の少なくとも一方が、該気体雰囲気の圧力と該反応ガス供給口から供給される反応ガスの圧力との差圧によって、該試料の被処理面と前記壁面とが微小間隔を隔てて浮上するように可動に構成されており、該微小間隔によって、該反応ガス供給口から該気体雰囲気に向けて低コンダクタンスの気体流路が形成されるとともに、前記差圧によって該気体雰囲気よりも高い圧力を有する高圧反応ガス領域が該低コンダクタンスの気体流路における前記反応ガス供給口から離れた位置に局所的に形成され、該電極に電力を印加して、該高圧反応ガス領域に該反応ガスに基づく局所的な高圧プラズマを発生させることにより、該高圧プラズマ中の反応ガスの反応種によって該試料に対する表面処理が行われ、そのことによって、上記の目的が達成される。
好ましくは、前記試料は試料台に載置されている。
好ましくは、前記気体雰囲気の圧力ｐ０と、前記高圧反応ガス領域における前記高圧プラズマの発生箇所の圧力ｐｘとの比を、ｐｘ／ｐ０＞１に設定する手段を更に備える。
好ましくは、前記電極の壁面が、前記試料の被処理面に対して微小間隙を隔てて対向して配置される。
好ましくは、前記電極及び前記試料台の少なくとも一方は、前記差圧によって、該電極及び該試料台の他方に対して微小間隙を隔てて浮上するように可動に構成されている。
好ましくは、前記電極及び前記試料台の少なくとも一方には、所定の大きさの磁力を発生する磁力発生機構が設けられていて、該磁力発生機構から発生する磁力と、前記差圧との両方を利用して、該電極及び該試料台の一方を他方に対して微小間隙を隔てて浮上させる。
好ましくは、前記電極の内部には、前記電極の壁面における前記反応ガス供給口から離れた位置に開放端を有する電力伝送線路が設けられており、該電力伝送線路は、該電極に印加された電力を該開放端まで伝送して、伝送された電力によって、該開放端の近傍に高電界を発生させる。
好ましくは、前記電力伝送線路は、電力が印加される内側導体と、絶縁体を介して該内側導体を覆い且つ接地されている電界遮蔽導体とによって構成されている。
好ましくは、前記電極に印加される電力は、１０ＭＨｚから１ＧＨｚの周波数帯の高周波電力、或いは１ＧＨｚ以上の周波数帯のマイクロ波電力である。
好ましくは、前記電力伝送線路は、導波管によって構成されている。
好ましくは、前記電極及び前記試料台の少なくとも一方に、使用する電源の周波数の電磁波に対して大きな吸収係数を持つ電力吸収体が設けられており、該電力吸収体は、前記低コンダクタンスの気体流路において前記高圧プラズマの発生領域よりも低圧力側に配置され、該高圧プラズマの発生領域を通過した電磁波を吸収して、該高圧プラズマの周囲領域における前記気体雰囲気の中でのプラズマの発生を抑制する。
【００５４】
【発明の実施の形態】
具体的な本発明の実施形態の説明に先立って、まず、本発明における気体雰囲気内に配した試料近傍に成膜又は表面処理を行なうための高圧反応ガスを局所的に供給すると同時に、前記の気体雰囲気より局所的な高圧反応ガス領域を前記試料近傍に形成する様な気体の流れ場を構成する方式について、図２２及び図２３を参照して説明する。
【００５５】
図２２は、円板Ｈ０による気体の流れ場の形成を示す概略図である。
【００５６】
具体的には、被成膜試料Ｊの被成膜面形状が平面である場合、外半径Ｒ２、内半径Ｒ１、厚さＴ１の平面形状を持つ円板Ｈ０をギャップｔ０だけ離れて被成膜試料Ｊに対向させ、更に高圧気体供給路１０１によって半径Ｒ１の内径穴を通じて、圧力ｐｓの高圧気体を局所的に供給する。更に、この高圧気体は、円板Ｈ０−被成膜試料Ｊの間に形成された気体流路を通じて、圧力ｐ０の円板Ｈ０の周囲の気体雰囲気へ流れるものとする。
【００５７】
ここで、円板Ｈ０と被成膜試料Ｊとの間を流れる気体の重量流量ｗ、及び圧力分布ｐを、図２３を用いて求める。図２３は、円板Ｈ０と被成膜試料Ｊとの間に円筒座標軸を設定した図である。
【００５８】
図２３に示される様に、被成膜平面及び円板Ｈ０に垂直で且つ円板Ｈ０の中心を通る直線をｚ軸とし、前記ｚ軸が被成膜平面と交わる点を原点Ｏとする。更に、図２３の様に、原点Ｏを通り且つ被成膜平面上にある直線を円筒座標系のｒ軸とし、また、そこから反時計周りに回転角θ０をとるものとする。
【００５９】
まず第１に、円板Ｈ０と被成膜試料Ｊとの間を流れる気体の重量流量ｗを求める。前記気体の流量ｗは、粘性を考慮した気体の運動方程式であるナビエ・ストークス方程式によって規定される流速を用いて求めることができる。このナビエ・ストークス方程式を円筒座標系で示すと、以下の式（１）のようになる。
【００６０】
【数１】

【００６１】
ここで、円板Ｈ０−被成膜試料Ｊの間を流れる気体流量ｗを求めるために、以下の仮定を行なう：
（１）円板Ｈ０−被成膜試料Ｊの間の距離ｔ０は円板外半径Ｒ２に比べて非常に小さい
（２）円板Ｈ０−被成膜試料Ｊの間の流れは、発達した境界層流れである
（３）ｚ軸方向に圧力分布はなく、従ってｚ軸方向の気体の速度を無視する
（４）θ方向にも圧力分布はなく、従ってθ軸方向の気体の速度も無視する
（５）圧力勾配の項に比べて、慣性力の項は小さい
（６）主なる粘性力はδ^２ｖ_ｒ／δｚ^２のみであり、他は無視する。
以上の仮定を式（１）に当てはめると、以下の式（２）のように簡略化される。
【００６２】
【数２】

【００６３】
但し、ｐはｒ方向の圧力分布、ｖ_ｒはｒ方向の流速分布、及びμは気体の粘性係数である。
【００６４】
壁面においては、気体の速度は壁面の速度に等しいとすることができるので、境界条件は、
【００６５】
【数３】

【００６６】
となる。圧力ｐはｚ方向に分布を持たないので、式（２）を式（３）の境界条件について解くと、
【００６７】
【数４】

【００６８】
が得られる。従って、円板Ｈ０−被成膜試料Ｊの間を流れる気体の重量流量ｗは、
【００６９】
【数５】

【００７０】
と表される。但し、ρは気体の密度である。
【００７１】
一方、気体の状態方程式より得られる以下の式（６）、
【００７２】
【数６】

【００７３】
（但し、ｍは気体の分子量ｍ、Ｒ０は気体定数、Ｔ０は絶対温度）を式（５）に代入すると、
【００７４】
【数７】

【００７５】
が得られる。ここで、ｗはｒによらず一定値をとらなければならないため、
【００７６】
【数８】

【００７７】
が得られる。これより、
【００７８】
【数９】

【００７９】
が得られる（但し、Ｅ０及びＦ０はそれぞれ積分定数）。これに境界条件を代入すると、
【００８０】
【数１０】

【００８１】
【数１１】

【００８２】
が得られる。従って、円板Ｈ０の下面に、円板Ｈ０−被成膜試料Ｊの間の気体圧力によって働く力は、上記の式（１０）を積分して、
【００８３】
【数１２】

【００８４】
から求めることができる。また、同時に、円板Ｈ０の上面には、周囲雰囲気の圧力ｐ０が働くため、円板Ｈ０には重力を除いて、
【００８５】
【数１３】

【００８６】
なる力ｆが、ｚ軸の正方向に働く。
【００８７】
また、式（１１）より、
【００８８】
【数１４】

【００８９】
【数１５】

【００９０】
【数１６】

【００９１】
が得られる。このとき、式（１６）の中のｗは流量、ｐｓ−ｐ０は差圧であるため、Ｃ０はコンダクタンスを表し、以下の式（１７）、
【００９２】
【数１７】

【００９３】
で表される。
【００９４】
ここで、円板Ｈ０−被成膜試料Ｊで構成される気体流路のコンダクタンスＣ０は、圧力ｐｓ及びｐ０によって変化するが、幾何学的境界条件によってこのコンダクタンスＣ０を設定する場合には、ｔ０、Ｒ２、Ｒ１に依存する。
【００９５】
上記において、プラズマを発生させる気体の圧力を、例えば大気圧近傍の高圧力に設定し、多くの気体分子をプラズマ中に供給して高い成膜速度を達成する方式が、従来技術として説明した方式である。
【００９６】
ここで、圧力ｐｓ１で気体を供給し、要求される所定の気体の流量をｗ１とし、その時の円板Ｈ０の周囲圧力をｐ０１、その時の気体の物性及び円板による境界条件Ｒ１、Ｒ２、ｔ０によって決定される定数ｃの値をｃ＝ｃ１、コンダクタンスをＣ０＝Ｃ０１とする。
【００９７】
ここで、プラズマを発生させるために供給する気体の種類（分子量ｍ）、圧力（ｐｓ）、温度（Ｔ）は、被成膜試料Ｊ、及び目的とする膜仕様やプラズマ現象等によって決定されるため、変更することができない。変更可能であるパラメータは、円板周囲の雰囲気圧力ｐ０、及び円板Ｈ０の配置、すなわち境界条件Ｒ１、Ｒ２、ｔ０である。
【００９８】
まず、ｃ＝ｃ１が非常に大きくなるようにＲ１、Ｒ２、ｔ０を設定する場合を考える。これは、供給部から円板周囲への気体流路の幅ｔ０を広くし、Ｒ２／Ｒ１を大きくすることによって、高圧反応ガス供給部から周囲気体雰囲気への気体流路のコンダクタンスＣ０を高くした場合に相当する（Ｃ０＝Ｃ０１）。
【００９９】
このとき、式（１４）及び式（１５）より、ｐｓ１≒ｐ０１となり、高圧ガス供給部圧力ｐｓと円板周囲圧力ｐ０が等しくなる。また、式（１０）より、ｐ≒ｐｓ≒ｐ０（Ｒ１≦Ｒ≦Ｒ２）となり、高圧力供給部から周囲気体雰囲気への気体流路である円板Ｈ０−被成膜試料Ｊの間に圧力分布は発生しない。
【０１００】
これに対して、必要気体供給量ｗ１及び供給気体圧力ｐｓ１をそれぞれ同じ値に保ったままで、コンダクタンスＣ０を低くしてＣ０＝Ｃ０２とし（Ｃ０１＞Ｃ０２）、それに対応して周囲気体圧力ｐ０を小さく設定する場合を考える（ｐ０＝ｐ０２＜ｐｓ１≒ｐ０１）。
【０１０１】
このときには、式（１４）及び式（１５）より、気体流量ｗがｗ＝ｗ１＝ｃ２（ｐｓ１^２−ｐ０２^２）を保つようにＣ０２及びｐ０２が設定され、且つｐｓ１（供給部圧力）＞ｐ０２（円板Ｈ０の周囲雰囲気圧力）であるために、式（１０）によって示される圧力分布が、円板Ｈ０−被加工物Ｊの間、つまり低コンダクタンス流路部分に形成される。これより、円板Ｈ０−試料Ｊの間の圧力は、円板周囲の圧力ｐ０＝ｐ０２より、全て高圧力状態となる。
【０１０２】
以上の点を考慮すると、同じ圧力ｐｓ１によって気体を供給し、ある同じ気体の供給量ｗ１を実現する方法としては、
（１）供給部から周囲雰囲気への気体流路のコンダクタンスが大きくなる様に、気体の流れ場（今回は前記壁面Ｈ０）を設定し、供給圧力ｐｓと周囲圧力ｐ０とが等しい状態で気体を流す、或いは、
（２）前記のコンダクタンスが低くなる様に上記の壁面Ｈ０を設定し、供給圧力ｐｓと周囲圧力ｐ０との差圧が大きい状態で気体を流す、
という２通りのケースが存在することになる。
【０１０３】
ここで更に、円板Ｈ０−被成膜試料Ｊの間にプラズマを発生させ、高成膜速度を達成するためにｐｓを大きくして高圧力気体を供給するケースを考える。
【０１０４】
前述したように、上記（１）及び（２）の何れの場合においても、円板Ｈ０−被成膜試料Ｊの間には同じ気体流量ｗ＝ｗ１が流れ、（１）及び（２）の各々における成膜速度は同じである。
【０１０５】
しかし、前記（１）の場合には、供給部の圧力ｐｓ、プラズマを発生させる円板Ｈ０−被成膜試料Ｊの間、更に周囲圧力ｐ０に圧力分布はなく、全て同じ圧力である。ここで、プラズマ部は高圧力であるので、粒子の平均自由行程が短く、このために容易に衝突・凝縮して反応生成物を形成する。これらの反応生成物は、プラズマ中においては即座に再分解し、被成膜表面を汚染することはない。しかし、周囲気体雰囲気においては、その周囲雰囲気圧力がプラズマ部と同等の高圧力であるため、その平均自由行程の短さから、非常に頻繁に衝突・凝縮を繰り返し、粒径の大きい反応生成物が形成される。粒径の大きい反応生成物は、プラズマ中に拡散した場合においてもその粒径の大きさから即座に分解されず、被成膜表面に付着して膜中に取り込まれ、膜質を劣化させる。また、成膜後においても膜表面に付着し、高成膜速度を達成する代わりに加工物表面を汚染しやすくなる。なお、前述したようにプラズマ中において発生した反応生成物は即座に再分解されて粉状反応生成物は成長しないため、上記の問題点は、大きな粒径の反応生成物が、プラズマ外部の高圧力により成長することに起因する。
【０１０６】
反応生成物の発生を抑制するために周囲気体雰囲気圧力ｐ０＝ｐ０１を低くすると、供給部の圧力ｐｓ、プラズマを発生させる円板Ｈ０−被成膜試料Ｊの間、更に周囲圧力ｐ０が等しい状態であるため、プラズマ部の圧力も減少する。この結果、良好な膜質や清浄表面を得ることはできるが、高成膜速度を達成できない。
【０１０７】
これより、上記（１）の状態においては、高成膜速度及び清浄表面を同時に実現することができない。
【０１０８】
一方、上記の（２）のケースでは、高成膜速度を達成するための同じ気体供給量ｗ１が実現されると同時に、その気体流路のコンダクタンスＣ０の低さから、供給部の圧力ｐｓに対してｐｓ＞ｐ０２なる周囲雰囲気圧力ｐ０２が維持される。このような状態では、プラズマ中において発生した反応生成物は、（１）と同様に即座に再分解され、被成膜表面を汚染しない。更に（２）の場合には、周囲気体雰囲気も、プラズマを発生させる円板Ｈ０−被成膜試料Ｊの間より低圧力であるために、平均自由行程が比較的長い。このため、反応生成物の衝突及び凝縮が生じ難く、粒径の大きな反応生成物が成長せずに、清浄な成膜を行なうことができる。
【０１０９】
このように、上記（２）の場合には、プラズマ部を高圧力に設定することによって高成膜速度を達成し、同時に、周囲雰囲気がプラズマ部より低圧力であることから、良好な膜質で且つ清浄な被成膜表面を得ることができる。
【０１１０】
周囲圧力ｐ０が小さければ小さいほど、清浄な成膜を行なうことができる。この最小値は、ｐ０＝０、つまり周囲が真空状態のときである。
【０１１１】
上記（１）及び（２）の各々の場合において、供給圧力ｐｓ、周囲雰囲気ｐ０、重量流量ｗ、コンダクタンスＣ０、定数ｃの状態を示すと、以下の表４のようになる。
【０１１２】
【表４】

【０１１３】
本発明では、高圧ガス供給部から円板Ｈ０の周囲の雰囲気への気体流路を、内半径Ｒ１及び外半径Ｒ２である円板Ｈ０と、そこから間隔ｔ０だけ離れて対向させた被成膜試料Ｊによって形成する。この気体流路のコンダクタンスも、粘性気体の運動方程式であるナビエ・ストークス方程式（式１）を用いて求めた。
【０１１４】
但し、高圧ガス供給部と周囲雰囲気との差圧は、高圧ガス供給部から周囲雰囲気への気体の流れ場を設定し、更に流れ場のコンダクタンスを低くすることによって、形成することができる。このときの具体的な手法としては、円板Ｈ０−被加工物Ｊの間の間隔ｔ０を小さくし、Ｒ２／Ｒ１を大きくする方法に限定されるものではない。また、流れる気体の圧力が低い場合におけるコンダクタンスＣ０は、実際には、上述のナビエ・ストークス方程式によってではなく、気体分子運動論を用いて求めなければならない。しかし、コンダクタンスＣ０の求め方に関わらず、高圧ガス供給部から周囲の雰囲気への気体流路を低いコンダクタンスに設定することによって、先に（２）の場合に示したような、高い成膜速度での清浄表面の形成が実現される。
【０１１５】
以下には、以上のような考察に基づいて達成された本発明のプラズマを用いた表面処理（成膜或いは表面改質）の方法及び装置を、添付の図面を参照しながら説明する。
【０１１６】
（第１の実施形態）
図１は、電極浮上型高圧浮上電極Ｈ１と、試料Ｊ、試料台Ｔ、走査ステージＳ、反応容器Ｃ、電源Ｇ、共振・整合装置Ｍ、フレキシブル電力伝送線路Ｉ、電力伝送線路Ｋ、高圧反応ガス供給装置Ｒ、排気装置Ｅ、電極走査装置Ｕ、及びそれらを制御する制御装置Ｎとの配置関係を示す全体概念図である。なお、図示しないが、試料−電極間ギャップを測定する試料−電極間ギャップ測定装置が設けられ、更に電極Ｈ１及び試料台Ｔには、それぞれの温度を調整するための水冷機構或いは加熱機構（不図示）が設けられる。また、試料台Ｔは、更に試料固定部Ｆを備えている。
【０１１７】
図２は、前述した電極浮上型高圧浮上電極Ｈ１の断面図である。
【０１１８】
図２において、１は、高圧反応ガスを高圧反応ガス供給装置Ｒから電極浮上型高圧浮上電極Ｈ１へ輸送する高圧反応ガス供給経路である。２は、電極浮上型高圧浮上電極Ｈ１の試料Ｊに対向する位置に設けられて、高圧反応ガス供給装置Ｒから輸送された高圧反応ガスを噴出する高圧力反応ガス供給口である。１１１は、高圧反応ガス供給口２から供給する反応ガスの圧力を、供給口２によって分布が発生しない様にするバッファ部であり、図中に描かれている複数のバッファ部１１１は、実際にはお互いにつながっている。３は、反応ガス排気口４と排気装置Ｅとをつなぐ反応生成物排気経路である。また、反応ガス排気口４は、排気装置Ｅにつながっており、局所的な高圧プラズマＰ（「局所高圧プラズマＰ」とも称する）の中での反応によって発生した反応生成物を排気する。５及び６は、それぞれ電極浮上型高圧浮上電極Ｈ１の内側電極及び外側電極である。１１は、内側電極５と外側電極６との間を絶縁する絶縁体であり、７は、内側電極５及び外側電極６と絶縁体１１とによって形成される電力伝送線路開放端である。８は、電極浮上型高圧浮上電極Ｈ１とフレキシブル電力伝送線路Ｉとを接続するコネクタである。９は、電極浮上型高圧浮上電極Ｈ１と駆動モータ１０とを接続する走査ワイヤ或いはベルトであり、これを通じて駆動モータ１０を回転させることによって、電極浮上型高圧浮上電極Ｈ１を試料Ｊに対して相対的に移動させる。走査ワイヤ（ベルト）９と駆動モータ１０とを総称して、走査装置Ｕと呼ぶ。
【０１１９】
図３は、電極浮上型高圧浮上電極Ｈ１の試料対向部分を表した下方斜面図である。
【０１２０】
図示されるように、電極浮上型高圧浮上電極Ｈ１の電極形状を、反応生成物排気口４を中心に持つ円盤型形状とする。また、高圧反応ガス供給口２は、図３の中に示される微小孔とし、この微小孔を同一円周上に多数個配置する。これらの微小孔は、ここから供給されるガスの圧力分布（流量分布）が均一になるように配置することが好ましく、具体的には、ある円周上に等間隔で配置されることが好ましい。また、局所高圧プラズマＰを発生させる電力伝送線路開放端７も、同様の円周形状とし、その形成位置は、高圧反応ガス供給口２よりも反応ガス排出口４に近い側に、十分離れて設ける。
【０１２１】
更に、図４は、試料Ｊと試料台Ｔとの間の段差ｔを示す部分断面図である。
【０１２２】
本発明の第１の実施形態においては、反応容器Ｃの内に試料Ｊ及び電極浮上型高圧浮上電極Ｈ１を対向させて配置し、高圧反応ガス供給装置Ｒより、目的とする膜特性などに基づいて決定された高圧反応ガスを、高圧反応ガス供給経路１を通じて電極浮上型高圧浮上電極Ｈ１に供給する。高圧浮上電極Ｈ１は、高圧浮上電極Ｈ１と試料Ｊとが対向する部分に、高圧反応ガスを高圧反応ガス供給口２より供給することによって、試料Ｊに対して微小間隔Ｄだけ浮上する。上記の構成では、電極Ｈ１と試料Ｊとの間の間隔Ｄが非常に狭いために、この部分に供給されたガスは、電極周囲の雰囲気に流出し難い。従って、電極Ｈ１と試料Ｊとに挟まれた部分が高圧力に維持されて、ここに高圧部分が形成される。
【０１２３】
これにより、低コンダクタンスの気体流路における差圧発生理論（先述の（２）のように供給圧力ｐｓと周囲圧力ｐ０との間の差圧を利用するケース）に関連して説明したように、高圧浮上電極Ｈ１の試料Ｊと対向する部分を、高圧反応ガス供給口２から反応容器Ｃ内の気体雰囲気へ向かう気体流路を低コンダクタンスな気体流路にする壁面とし、この低コンダクタンスにより、排気装置Ｅにより排気される反応容器Ｃ内の気体圧力より高圧力の反応ガス領域（高圧反応ガス領域）を、高圧浮上電極Ｈ１と試料Ｊの間の微小間隔Ｄによる低コンダクタンス部分に、局所的に形成する。
【０１２４】
更に、電源Ｇから発生した電力は、電力伝送線路Ｋ、共振・整合装置Ｍ、フレキシブル電力伝送線路Ｉを通じて高圧浮上電極Ｈ１に伝達され、更に内側電極５、外側電極６、及び絶縁体１１によって構成される電極内電力伝送線路を通じて、高圧浮上電極Ｈ１の試料Ｊと対向する部分であって且つ高圧反応ガス供給口２より離れた位置に設けられた電力伝送線路開放端７に伝達される。これによって発生された高電界は、電力伝送線路開放端７の位置、すなわち高圧浮上電極Ｈ１と試料Ｊとの間の微小間隔Ｄの中の高圧力反応ガス領域中であって、且つ高圧反応ガス供給口２より離れた部分に、局所高圧プラズマＰを発生させる。この局所高圧プラズマＰの中で高圧反応ガスを分解・活性化し、プラズマＰの直下における試料Ｊに対して成膜を行う。
【０１２５】
プラズマＰにおいて生じた反応生成物は、反応生成物排気口４から、反応生成物排気経路３を通じて排気装置Ｅによって即座に排気される。また、反応容器Ｃ内の気体雰囲気へ流れた反応生成物は、反応容器Ｃ全体を同様に排気装置Ｅによって即座に排気することにより、除去される。
【０１２６】
更に、以上の構成では、走査装置Ｕ及び走査ステージＳを用いて高圧浮上電極Ｈ１と試料Ｊとの相対的位置を変化させることによって、試料Ｊの表面の全体に渡って成膜を行うことができる。また、制御装置Ｎによって、所望の成膜を行うための制御が行われる。
【０１２７】
このように、以上の構成では、高圧浮上電極Ｈ１と試料Ｊとの間の微小間隔Ｄ中の高圧力雰囲気に局所高圧プラズマＰを発生させるため、高密度な活性種を生成でき、その結果として高い成膜速度を実現できる。また、同時に、反応容器Ｃ内の圧力（周囲気体雰囲気の圧力）が、局所高圧プラズマＰが発生して成膜が行われている高圧浮上電極Ｈ１と試料Ｊとの間の高圧力雰囲気に比べて低圧に、或いは真空に維持されていることから、前述したように、粒径の大きな反応生成物が成長することは無く、試料Ｊに良質な膜を形成できて、且つ膜表面も清浄に維持できる。
【０１２８】
反応容器Ｃ内の圧力が低いほど、清浄な膜表面が得られて、良質な成膜を行なうことができる。特に、反応容器Ｃ内の雰囲気が真空である場合に、最大の効果を得ることができる。
【０１２９】
また、反応容器Ｃ内の圧力が１気圧以下である場合には、反応容器Ｃの外の大気よりも圧力が低いため、ガス漏洩時においても反応容器Ｃの中のガス雰囲気が反応容器Ｃの外に漏洩せず、装置の安全性を高めることができる。
【０１３０】
更に、反応容器Ｃ内の雰囲気が真空雰囲気である場合は、試料Ｊを反応容器Ｃの外に搬出する際の反応ガスパージ時に、反応ガスを排気する時間を非常に短く、或いは完全に無くすことができるので、装置のスループットが向上する。
【０１３１】
また、以上のように、微小間隔Ｄの高圧力と反応容器Ｃ内の雰囲気（周囲気体雰囲気）との差圧により、電極Ｈ１を試料Ｊに対して浮上させるので、電極Ｈ１が試料Ｊに対して傾くこと無く、微小間隔Ｄを維持することができる。また、前記微小間隔Ｄ中には、試料表面に沿って、高圧反応ガス供給口２から反応容器Ｃ内の雰囲気或いは反応生成物排気口４へ向かう反応ガスのよどみの無い流れが形成されており、このような流れが形成される微小間隔Ｄ中に局所高圧プラズマＰを発生させることにより、膜厚分布の均一な膜を形成することができる。
【０１３２】
また、高圧反応ガス供給口２の直下でなく、供給口２より離れた部分に局所高圧プラズマＰを発生させることにより、供給口２の反応ガス噴出流によって供給口２の周辺の成膜量より供給口２の直下の成膜量が多くなるような成膜量分布が形成されることがない。これによって、膜厚分布の均一な成膜を行うことができる。
【０１３３】
更に、以下には、
（１）電極Ｈ１を試料Ｊに対して微小間隔Ｄだけ浮上させる方式及びその効果、
（２）電力伝送線路開放端７によってプラズマＰを発生させる方式及びその効果、
（３）良質な膜質及び清浄な成膜表面を得る方式、並びに
（４）ガス供給口２の直下における成膜量分布の形成防止方式
について、詳述する。
【０１３４】
まず、（１）として、電極Ｈ１を試料Ｊに対して微小間隔Ｄだけ浮上させる方式について説明する。
【０１３５】
図５（ａ）は、電極浮上型高圧浮上電極Ｈ１−試料Ｊの間の微小間隔Ｄの近傍の模式的断面図であり、図５（ｂ）は、上記の微小間隔Ｄ中の高圧反応ガスの圧力分布を示す模式図である。図５（ｂ）において、Ｐ０は高圧反応ガス供給口部の圧力、Ｐ１は反応容器内の気体圧力、並びに、Ｐ２は反応ガス排気口部の圧力である。
【０１３６】
この圧力分布は、図２２として示されるような簡単な場合においては、代数的に規定することができ、同時に、気体圧力より受ける力を前記式（１３）により計算できる。しかし、電極Ｈ１のように高圧反応ガス供給口２を多数持つ場合には、代数的に求めることはできず、有限要素法等の方法を用いて数値解析を行なうことになる。同様に、気体圧力より電極Ｈ１が同時に受ける力も、数値解析的に求めることになる。
【０１３７】
高圧反応ガス供給装置Ｒより、反応ガス種、温度、圧力、流量、混合比を制御されながら供給された高圧反応ガスは、高圧反応ガス供給経路１を通じて、電極浮上型高圧浮上電極Ｈ１の内部へと供給される。電極浮上型高圧浮上電極Ｈ１の内部へ供給された高圧反応ガスは、図２の断面図に示される電極浮上型高圧浮上電極Ｈ１において、試料Ｊと対向する位置に設けられた高圧力反応ガス供給口２から、高圧浮上電極Ｈ１と試料Ｊとの間隔へ供給される。そして、排気装置Ｅにより排気されて低圧或いは真空となった反応容器Ｃ内の気体雰囲気との差圧による力を受けて、電極浮上型高圧浮上電極Ｈ１を試料Ｊより微小間隔Ｄだけ浮上させる。
【０１３８】
微小間隔Ｄの浮上量が小さいため、高圧力反応ガス供給口２から反応容器Ｃの低圧或いは真空雰囲気へと向かう気体流路のコンダクタンスは非常に小さくなり、図５中の反応ガス供給口２における反応ガス供給圧力Ｐ０から、反応容器Ｃの低圧或いは真空雰囲気の圧力Ｐ１へ、連続的に変化する圧力分布を形成する。同時に、電極浮上型高圧浮上電極Ｈ１の試料対向部分１２に開口すると共に反応生成物排気経路３を通じて排気装置Ｅに接続され、微小間隔Ｄ中の反応ガス及び反応生成物を排気する反応ガス排気口４には、圧力Ｐ２（Ｐ２＜Ｐ０）の低圧雰囲気が形成されている。これによって、同様に、高圧反応ガス供給口２における圧力Ｐ０から、反応ガス排気口４の周辺領域の低圧力Ｐ２へ変化する圧力分布を形成する。このような微小間隔Ｄによって変化する圧力分布による反応容器Ｃ内の雰囲気との差圧と電極Ｈ１の重量とのバランスによって、電極Ｈ１は浮上する。
【０１３９】
この微小間隔Ｄは、反応ガス供給圧力Ｐ０、反応容器内圧力Ｐ１、電極重量、電極−試料対向面積、高圧反応ガス供給口２の出口形状、高圧浮上電極内の反応生成物排気口における排気速度によって決定される。そこで、図示しない試料電極間ギャップ測定装置によって電極―試料間隔を測定し、反応ガス供給圧力Ｐ０、温度、混合比また周囲圧力、温度等を制御することによって、電極Ｈ１と試料Ｊの広い対向面積に対して、電極―試料間隔を、１μｍ〜数百μｍの微小間隔に安定して制御できる。
【０１４０】
この時、電極間ギャップ測定装置によって電極―試料間隔を測定し、ステージＳによって電極―試料間隔を一定に保つことも、原理的には可能である。しかし、実際には、プラズマの熱による電極Ｈ１及び試料Ｊの変形、プラズマを発生させるための電界、更に腐食性雰囲気によって、精密なギャップ測定を行なうことが困難である。この様な場合においても、本発明によれば、電極―試料間の圧力と反応容器Ｃ内の雰囲気との差圧を用いて電極Ｈ１を試料Ｊに対して浮上させることにより、電極Ｈ１と試料Ｊの広い対向面積に対して、電極―試料間隔を１μｍから数百μｍの微小間隔に、安定して制御することができる。
【０１４１】
更に、図示しないが、磁性体或いは磁力発生機構を必要に応じて電極Ｈ１及び試料台に設け、この磁性体或いは磁力発生機構から発生する磁力によって電極Ｈ１を浮上させれば、高圧反応ガス供給口部の圧力Ｐ０を低く設定することが可能となり、電極Ｈ１の重量でなく目的とする膜特性によって、高圧反応ガス供給口部の圧力条件を設定することも可能になる。
【０１４２】
次に、（２）として、微小間隔Ｄ中の高圧反応ガス領域に局所高圧プラズマＰを発生させる方式について、説明する。
【０１４３】
図６は、電極浮上型高圧浮上電極Ｈ１の試料Ｊと対向する部分に設けられた電力伝送線路開放端７における、局所高圧プラズマＰの発生を示す概略図である。
【０１４４】
図１の電源Ｇより発生した電力は、電力伝送線路Ｋを通り、共振・整合装置Ｍに達する。共振・整合装置Ｍにより必要に応じて昇圧及びインピーダンスマッチングを行われた電力は、効率よく高圧浮上電極Ｈ１へ伝達される。共振・整合装置Ｍにより昇圧された電力は、フレキシブル電力伝送線路Ｉを通じて電極浮上型高圧浮上電極Ｈ１に供給され、更に、内側電極５、外側電極６、及び絶縁体１１によって構成される電極内電力伝送線路を通じて、高圧浮上電極Ｈ１の試料Ｊに対向する部分であって且つ高圧反応ガス供給口２より離れた位置に設けられた電力伝送線路開放端７に達する。
【０１４５】
電力伝送線路開放端７は、図２に示される実施形態においては、電源Ｇより直流或いは交流電圧を伝送する電力伝送線路Ｋ、フレキシブル電力伝送線路Ｉ、及び電極内電力伝送線路が、最終的に高圧浮上電極Ｈ１の試料対向部分１２において、絶縁体１１によって内側電極５と外側電極６とが絶縁された状態のままで終端している部分を意味する。この電力伝送線路開放端７の設置により、図６に示されるように、内側電極５と外側電極６との間で高電圧或いは強電界を発生させて、試料Ｊの有無に関係なく、内側電極５と外側電極６との間でプラズマＰを発生させることが可能になる。更に、外側電極６−内側電極５間以外にプラズマＰが拡大することを抑制することができ、局所高圧プラズマＰを発生させることができる。
【０１４６】
電力伝送線路開放端７は、高圧浮上電極Ｈ１の試料対向部分１２に形成されているため、高圧浮上電極Ｈ１−試料Ｊの間の高圧反応ガス領域に、局所高圧プラズマＰを発生させる。局所高圧プラズマＰの中で高圧反応ガスは解離し、反応ガスに基づく活性種を発生して試料Ｊの表面に成膜を行う。高圧反応ガスに基づいて活性種は非常に高密度となり、高速度な成膜を行うことを可能とする。
【０１４７】
本実施形態の場合には、内側電極５をカソード電極、外側電極６をアノード電極として、試料Ｊの有無に関係なく、内側電極５と外側電極６との間でプラズマＰを発生させることが可能であるため、電極走査の際に電力伝送線路Ｋの等価回路が変化せず、プラズマＰが安定して、均一な膜厚分布を得ることができる。このプラズマＰの安定は、内側電極５をカソード電極、外側電極６をアノード電極とする場合に限らず、電力伝送線路開放端において高電界を発生させて、試料Ｊの有無に関係なくプラズマＰを発生させることに起因する。
【０１４８】
更に、ここで図示しないが、電極Ｈ１及び試料台Ｔの少なくとも何れか一方に、使用する電源Ｇの周波数の電磁波に対して大きな吸収係数を持つ電力吸収体を、反応ガス供給部２から周囲の気体雰囲気へ流れる低コンダクタンス流路のうちで局所高圧プラズマＰが発生する領域より低圧力側に設ければ、局所高圧プラズマＰで消費されず通過した電磁波を吸収することができる。これにより、特に反応容器内圧力が真空雰囲気である場合に、周囲の気体雰囲気にプラズマが発生することを防ぐことができる。更に、上記のような電力吸収体を設ければ、電極走査の際に電力伝送線路Ｋの等価回路が変化せず、プラズマが安定して、更に均一な膜厚分布を得ることができる。
【０１４９】
次に、（３）として、本実施形態によって、高速度で試料Ｊの成膜を行い、且つ良好な膜質を有する清浄な成膜表面を得る方式について、以下に説明する。
【０１５０】
本発明においては、高圧反応ガス領域中における局所高圧プラズマにより高圧反応ガスに基づく高密度活性種を発生させて、試料Ｊに対する高成膜速度を達成し、同時に、反応容器内圧力を局所高圧プラズマ発生部の圧力より低く或いは真空に維持することによって、良質な膜質及び清浄な成膜表面を得る。反応ガスに用いるガス種、温度、圧力は、目的とする膜材料によって選択されなければならない。また、反応ガス種に用いるガスは、一種類に限定されず、希ガス或いは他の反応ガスと混合させて、最適条件を設定する。
【０１５１】
高圧反応ガス供給口２より供給された高圧反応ガスは、図５に示されるように高圧反応ガス供給口２の高圧力Ｐ０から、低圧或いは真空雰囲気に排気された反応容器内の圧力Ｐ１或いは反応ガス排気口４の圧力Ｐ２へ、連続的に変化する圧力分布に従って移動する。そして、高圧浮上電極Ｈ１の試料対向部分１２に設けられた電力伝送線路開放端７に発生した局所高圧プラズマＰにおいて、分解・励起され、反応ガスに基づく活性種を発生して、局所高圧プラズマＰの直下で成膜を行う。
【０１５２】
ここで、局所高圧プラズマＰによる反応において生じるのは、成膜に寄与する活性種のみでなく、他に、成膜に寄与しない分子や原子、及びそれらが互いに或いは反応容器内の炭化粉末物や金属粉末物などと付着・重合した反応生成物も、生じる。この炭化粉末物や金属粉末物などは、供給ガス、電極材料、反応容器材料などの各種構造物材料から発生する。これらを、不純物と呼ぶ。上記のような反応生成物も試料Ｊの表面に到達するが、試料Ｊの表面にこれらの反応生成物が付着したままで成膜が進行すると、反応生成物が膜中に取り込まれて膜質を劣化させる。
【０１５３】
プラズマ中においては、凝縮した反応生成物は、粒径が小さい場合はプラズマによって即座に再分解され、反応生成物として基板表面に到達することはない。しかし、プラズマ外部に放出された反応生成物は再分解されること無く、互いに或いは容易に反応容器内の不純物と凝縮する。これによって、反応生成物の粒径が増大し、また、粒径の大きい反応生成物の粒子数が増大する。ここで問題となるのは、上記のようにして生成される、粒径の大きな反応生成物である。それらの粒径の大きな反応生成物は、再びプラズマ中に拡散した場合においても即座に再分解されず、ある一定の粒子径を持ったままで試料基板Ｊに到達して、基板Ｊの上に形成された膜中に混入することによって、膜質を著しく低下させる。或いは、粒径の大きな反応生成物は、反応容器Ｃの内壁に付着して、反応容器Ｃの内部を汚染し、その結果として、成膜後の膜表面を汚染してプロセス自体の歩留りを悪化させる。
【０１５４】
上記で問題となるのは、プラズマの外部が、プラズマ部と同等の圧力状態である点である。このために、プラズマ外部に放出された反応生成物が成膜室内を長時間浮遊し、その間に、高圧力雰囲気に起因する平均自由行程の短さから互いに或いは反応容器中の不純物と多数回の衝突・凝縮を繰り返して、反応生成物の粒径の増大や粒径の大きい反応生成物の粒子数の増大を引き起こす。また、前述したように再びプラズマ中に拡散した場合においても、即座に再分解されずに試料Ｊの表面に到達し、膜中に混入することによって膜質を著しく低下させる。
【０１５５】
これに対して本実施形態では、試料Ｊに高圧浮上電極Ｈ１を対向させ、高圧反応ガス供給口２から反応容器Ｃの内部雰囲気への気体流路を、低コンダクタンスな気体流路とする。これにより、試料Ｊ−電極Ｈ１間の気体流路部分に反応容器Ｃ内の雰囲気圧力より高圧力な反応ガス領域を形成し、そこにプラズマＰを発生させることにより高成膜速度を達成する。その一方で、反応容器Ｃ内の雰囲気圧力はプラズマ部より低圧力であるため、平均自由行程が大きくなる。これによって、反応生成物が互いに衝突・凝縮せず、反応生成物の粒径が大きく成長しない。粒径の小さい反応生成物は、プラズマに拡散した場合に即座に再分解され、成膜表面に到達することが無いので、良質な膜質及び清浄な膜表面を得ることができる。
【０１５６】
反応容器Ｃ内の雰囲気圧力は、低圧であるほど良質な膜質及び清浄な膜表面を得ることができ、真空雰囲気がその下限となることは言うまでもない。
【０１５７】
また、高圧浮上電極Ｈ１−試料Ｊの間の微小間隔Ｄ中の試料表面に沿った流れによる、局所高圧プラズマＰ中で発生した反応生成物の輸送及び除去について考えると、局所高圧プラズマＰ中の高圧反応ガスに基づく反応生成物は、試料表面に沿った流れによって速やかに局所高圧プラズマＰから移動し、一定領域によどむことの無いまま、高圧浮上電極Ｈ１中に設けられた反応ガス排気口４を通じて反応ガス排気装置Ｅへ排出される。これによって、膜表面或いは反応容器内の雰囲気の清浄化が実現される。また同時に、反応生成物は、よどむことの無いままに高圧浮上電極Ｈ１の周囲の真空或いは低圧雰囲気にも放出される。反応容器Ｃの内部を常時排気して真空或いは一定の圧力以下に維持することで、放出された反応生成物の雰囲気パーティクルとの凝縮や被加工物表面への再付着を避けることができて、反応容器内及び膜表面の清浄化を実現することができる。
【０１５８】
なお、反応容器Ｃから排気されたガスを再処理して、反応ガス或いは反応容器Ｃ内の周囲気体雰囲気として、反応容器Ｃに再び供給する手段を更に備えることも可能である。
【０１５９】
更に、本実施例において、電力伝送線路開放端７を高圧反応ガス供給口２より離れた位置に設置することによる、高圧反応ガス供給口２の直下における成膜量分布形成の防止について、更に説明する。
【０１６０】
図７（ａ）は、高圧反応ガス供給口２の近傍における構成を模式的に示す断面図であり、図７（ｂ）は、図７（ａ）の構成を利用して高圧反応ガス供給口２を含む近傍に局所高圧プラズマＰを発生させる場合に、供給口２の直下に形成される膜厚分布を示す断面図、更に図７（ｃ）は、上記に際して微小間隙Ｄに発生するガス流の状態を模式的に示す図である。一方、図８（ａ）は、高圧反応ガス供給口２から離れた位置に電力伝送線路開放端７を設置する場合の、高圧反応ガス供給口２及び線路開放端７の近傍における構成を模式的に示す断面図であり、図８（ｂ）は、図８（ａ）の構成を利用して高圧反応ガス供給口２を含む近傍に局所高圧プラズマＰを発生させる場合に、供給口２の直下に形成される膜厚分布を示す断面図、更に図８（ｃ）は、上記に際して微小間隙Ｄに発生するガス流の状態を模式的に示す図である。図７（ｂ）及び図８（ｂ）において、１７１１は、高圧反応ガス供給口２を含む近傍に局所高圧プラズマＰを発生させる場合に供給口２の直下に形成される成膜量分布、１７１２は、高圧反応ガス供給口２から離れた位置に電力伝送線路開放端７を設置して局所高圧プラズマＰを発生させる場合に局所高圧プラズマＰの直下に形成される成膜量分布である。また、図７（ａ）及び図８（ａ）において、１６１１は、高圧反応ガス供給口２から噴出する高圧反応ガス噴出流、１６１２は、微小間隔Ｄ中で試料表面に沿う流れとなった高圧反応ガス流であり、図７（ｃ）及び図８（ｃ）において、１６１３は、供給口２の近傍で乱流になった反応ガスの流速分布、１６１４は、供給口２から離れて、せん断流へ変化する反応ガスの流速分布、１６１５は、供給口２から十分に離れて、せん断流になった反応ガスの流速分布である。
【０１６１】
高圧浮上電極Ｈ１−試料Ｊの間の微小間隔Ｄの中の高圧反応ガスの流速分布においては、高圧反応ガス供給口２の直下及びその近傍においては乱流１６１３が発生し、その流速分布は乱れた分布となって、また時間的に変化する非定常流になる。この場合には、試料表面に沿った流速分布のみではなく、試料表面に垂直な方向にも流速分布を有する。しかし、供給口２から離れるに従って、流速分布は１６１４に示すように次第に安定化し、試料表面に沿った方向の流速分布のみを有するようになる。最終的には、微小間隔Ｄ及び反応ガスの流速などのパラメータにもよるが、１６１５に示されるように、試料表面に沿った流速分布のみを有する定常せん断流になる。参照番号１６１５で示される、この定常せん断流の流速分布Ｕは、以下の式（１８）、
【０１６２】
【数１８】

【０１６３】
で表される。但し、上記の式（１８）において、微小間隔Ｄの中心に座標原点をとり、試料表面に垂直な方向にｘ軸をとるものとし、Ｕは、原点から距離ｘだけ離れた位置における試料表面に沿った方向の流速分布、Ｕｍａｘは、原点、すなわち微小間隔Ｄの中心に発生する最大流速、ｘは、原点からの距離である。
【０１６４】
高圧反応ガス供給口２の直下を含む高圧浮上電極Ｈ１の試料対向部分１２の全面でプラズマを発生させる場合、試料Ｊの成膜領域は、プラズマ発生領域、即ち、高圧反応ガス供給口２の直下を含む高圧浮上電極Ｈ１の試料対向部分全面となる。このとき、図７（ａ）に示されるように、特に高圧反応ガス供給口２の直下においては、噴出した高圧反応ガス流１６１１が試料表面に、該試料表面に垂直な方向から衝突し、時間的に流速分布が変化する不安定な乱流が発生している。従って、反応ガス供給口２の直下では、反応ガス供給口２の周辺以外で試料表面に沿う流れ１６１２（流速分布１６１５）が形成されている領域に比べて、成膜量が多くなる。このため、図７（ｂ）に１７１１として示されるような成膜量分布を形成する。従って、高圧浮上電極Ｈ１の走査を行って試料全面の成膜を行う際に、高圧反応ガス供給口２の位置と電極Ｈ１を走査する軌跡によって決定される膜厚分布が、成膜後の成膜表面に形成される。
【０１６５】
そこで、本実施形態では、図８（ａ）に示される様に、内側電極５及び外側電極６によって構成される電力伝送線路開放端７にプラズマを発生させることにより、プラズマ発生領域を規定して局所高圧プラズマＰとする。また、局所高圧プラズマＰの位置を高圧反応ガス供給口２より十分離れた位置であって、安定したせん断流１６１５が発生している領域に設置することで、高圧反応ガス供給口２の直下における成膜量分布１７１１の形成を防ぎ、微小間隔Ｄ中の試料表面に沿う流れによって、局所高圧プラズマＰの発生部における成膜を行うことにより、非常に安定した前記局所プラズマ直下の加工量分布１７１２を得る。この状態で成膜領域を試料全体に走査させることにより、成膜量分布の無い均一な成膜を行なうことができる。
【０１６６】
本発明の表面処理では、局所的な高圧プラズマＰを発生させて、そのプラズマ近傍の局所的な成膜を行い、電極Ｈ１と試料Ｊとを相対的に移動させることによって試料表面全体の成膜を行う。また、電極Ｈ１と試料Ｊとの間の微小間隔Ｄ中の反応ガスの高圧力と電極重量、及び反応容器Ｃ内の低圧或いは真空雰囲気との釣合によって、微小間隔Ｄを形成している。これらのため、共振・整合装置Ｍと電極浮上型高圧浮上電極Ｈ１とを接続する電力伝送線路は、変形可能なフレキシブル電力伝送線路Ｉを用いることが望ましい。また、フレキシブル電力伝送線路Ｉと高圧浮上電極Ｈ１との接続は、コネクタ８によって行われ、この接続は、接続部での接触抵抗による損失、電磁波漏れの無い様に行わなければならない。
【０１６７】
絶縁体１１は、電力伝送線路開放端７に発生した局所高圧プラズマＰによって腐食されることの無い材料、例えば高純度アルミナ、窒化珪素等を用いることが望ましく、更に条件に応じて、膜材料を構成する元素を少なくとも１種類以上含む材料を用いることが望ましい。例えば、Ｓｉ膜を成膜する場合、絶縁体１１に窒化珪素（ＳｉＮ）を用いることにより、膜中への不純物混入を低減させることができる。
【０１６８】
試料固定部Ｆに関して、試料Ｊを固定する固定用治具が高圧浮上電極Ｈ１と対向する部分へ突出した場合、前述したように高圧浮上電極Ｈ１と試料Ｊは非常に接近しているため、接触による高圧浮上電極Ｈ１の試料対向部分１２の損傷や、微小間隔Ｄ内の圧力分布の変化など、好ましくない状態を引き起こす。従って、試料固定部Ｆは、真空チャックや静電チャック等の、試料固定治具などが電極対向部に突出しない機構を用いることが望ましい。
【０１６９】
また、図４に示される、試料Ｊと試料台Ｔの段差ｔは、微小間隔Ｄ内の高圧反応ガスの圧力分布を変化させ、試料Ｊに対する電極浮上型高圧浮上電極Ｈ１の電極傾斜を引き起こし、更には成膜速度分布の変化、電極表面への試料の接触等の問題を発生させるため、可能な限り小さくしなければならない。
【０１７０】
高圧浮上電極Ｈ１の試料対向部分１２に耐蝕性を有して高硬度の絶縁膜、例えばアルミナ溶射膜などを形成し、高精度に平坦化することにより、プラズマによる試料対向部分１２の腐食を軽減させ、寿命を長期化させた高圧浮上電極を実現することも可能である。
【０１７１】
図９のように、高精度に平坦化させた高精度平坦化耐蝕・高硬度絶縁体１８、例えば高純度アルミナ或いは窒化珪素などからなる絶縁体１８を、試料対向部１２の全体に取り付けることによって、膜形成の困難な耐蝕・高硬度絶縁材料を試料対向部分１２に用いることも可能である。
【０１７２】
或いは、図１０のように、反応ガス供給口２に多孔質材料１９、例えば多孔質アルミナ等を用いることによって、非常に安定して電極Ｈ１−試料Ｊの間の狭ギャップ間隔Ｄを制御することを可能とする高圧力浮上電極Ｈ１を実現することも可能である。
【０１７３】
また、高圧浮上電極Ｈ１において、高圧反応ガス供給口２及び反応ガス排気口４の位置及び数量は１つに限定されるものではない。例えば、図１１のように、試料台Ｔに、或いは高圧浮上電極Ｈ１及び試料台Ｔの両方に、高圧反応ガス供給口２及び反応ガス排気口４を設置することも可能である。
【０１７４】
先に図１を参照して説明した走査ステージＳは、目的に応じて、鉛直方向運動機構、水平方向運動機構、回転機構などを有することができる。また、試料台Ｔに固定される試料Ｊの数は、１つに限定されない。試料を多数固定する試料台を用いたバッチ処理を行うことにより、生産効率の向上を行うことができる。
【０１７５】
例えば、図１２は、多回転軸且つ回転数をもつ多数試料固定用試料台Ｔ１１を用いたバッチ処理を示す概念図である。図１２において、Ｔ１１は多数試料固定用試料台である。
【０１７６】
図１２に示される構成例においては、ＸＹＺ方向への多方向走査が可能な走査ステージＳ上に、回転機構θ１をもつ試料台Ｔ１１が設置され、更にＴ１１上には、試料台Ｔ１１の持つ回転機構θ１と同じ或いは異なる回転数、回転方向、回転軸の回転機構θをそれぞれ持つ試料台Ｔが多数個設置される。各試料台Ｔの上に試料Ｊをそれぞれ設置し、電極浮上型高圧浮上電極Ｈ１が試料Ｊに対向することにより、バッチ処理を行う。このとき、走査ワイヤ或いはベルト９を通じて電極Ｈ１を走査させ、また、走査ステージＳの多方向走査、或いは試料台Ｔ及び試料台Ｔ１１の回転機構を用いてランダムに加工を行うことによって、試料Ｊをそれぞれ均一に成膜し、非常に膜均一性の高い成膜を行なうと同時に、バッチ処理により生産効率の向上を行うことができる。
【０１７７】
高圧浮上電極Ｈ１−試料Ｊの間の微小間隔Ｄへ高圧反応ガスを供給する高圧反応ガス供給口２、反応生成物排気口４、及び高圧浮上電極Ｈ１の試料対向部分１２の形状は、試料Ｊの形状、大きさ、仕上げ精度など、目的とする成膜に応じて変化する。高圧浮上電極Ｈ１の実施形態は、これに限定しない。
【０１７８】
なお、反応容器Ｃの中に、試料などの横方向の位置決め用に高圧力部を形成することも可能である。但し、その場合の高圧力部は、上記で説明したところの「供給圧力よりも低い圧力を有する周囲気体雰囲気部」には含まれない。
【０１７９】
（第２の実施形態）
次に、試料浮上型高圧浮上電極Ｈ２を用いた本発明の第２の実施形態について、以下に説明する。
【０１８０】
本実施形態における試料浮上型高圧浮上電極Ｈ２とは、電力を電源Ｇより伝達されて局所高圧プラズマＰを発生し得る電極に対して、浮上試料Ａを浮上させる方式を用いた高圧浮上電極である。この場合、反応容器Ｃ内に設置されるのは試料浮上型高圧浮上電極Ｈ２であり、浮上するのは浮上試料Ａである。
【０１８１】
図１３は、試料浮上型高圧浮上電極Ｈ２の概略断面図であり、Ａは浮上試料、Ｈ２は試料浮上型高圧浮上電極、Ｙは浮上試料走査ワイヤー或いはベルトである。また、試料浮上型高圧浮上電極Ｈ２は、図１３には図示されない走査ステージＳ上に設置され、走査ステージＳにより試料浮上型高圧浮上電極Ｈ２を走査することにより、試料浮上型高圧浮上電極Ｈ２と浮上試料Ａとの相対的位置を変化させることができる。
【０１８２】
浮上試料走査ワイヤ或いはベルトＹは、図１３には図示されない駆動モータ１０に接続される。これより、電極浮上型高圧浮上電極Ｈ１と同様に、駆動モータ１０を回転させることによって浮上試料Ａを走査させて、試料浮上型高圧浮上電極Ｈ２と浮上試料Ａとの相対的位置を変化させることができる。駆動モータ１０及び浮上試料走査ワイヤ或いはベルトＹを総称して、試料台走査装置と呼ぶ。
【０１８３】
このように、本実施形態は、局所高圧プラズマＰを発生させる試料浮上型高圧浮上電極Ｈ２に対して、浮上試料Ａを微小間隔Ｄだけ浮上させる試料浮上方式を用いている。電極浮上型高圧浮上電極Ｈ１と同様に、微小間隔Ｄ中に発生した局所高圧プラズマＰ中の高圧反応ガスに基づく活性種により、浮上試料Ａの局所高圧プラズマＰの近傍に局所的な成膜を行う。また、走査ステージＳ及び試料台走査装置を用いて試料浮上型高圧浮上電極Ｈ２と浮上試料Ａの相対的位置を変化させることによって、試料Ａの表面に全体的な成膜を行う。また、本実施形態においては、第１の実施形態にて、電極浮上型高圧浮上電極Ｈ１に関して説明した高圧反応ガス供給口２の形状及び位置、反応生成物排気口４の形状及び位置、電力伝送線路開放端７の形状及び位置や構造は、第１の実施形態と同様とする。特に、本実施形態では、ガラス基板などの軽量な試料Ａに対して、比較的低圧な供給圧力によって試料Ａを試料台Ｔと共に浮上させることができる。これより、加工条件の圧力条件を広く設定することを可能し、同時に比較的容易に試料Ａの搬送を行うことができるので、装置全体の生産性を向上させることができる。
【０１８４】
なお、図１３に図示しない装置全体の構成、浮上試料Ａの浮上原理及び方式、局所高圧プラズマＰの発生原理及び方式、局所高圧プラズマＰ中における成膜現象、高成膜速度、膜質向上、及び成膜後の表面の清浄化を同時に実現する原理及び方式、高圧反応ガス供給口２より離れた位置に局所高圧プラズマＰを発生させて高圧反応ガス供給口２の直下における成膜量分布１７１１の形成を防止する原理及び方式については、電極浮上型高圧浮上電極Ｈ１と同様に、本実施形態においても適用できる。
【０１８５】
また、第１の実施形態で説明した高圧浮上電極Ｈ１の形状、電極浮上型高圧浮上電極Ｈ１の試料対向部１２に対する耐蝕・高硬度の絶縁膜の形成、図９に示した電極浮上型高圧浮上電極Ｈ１の試料対向部１２に対する高精度平坦化耐蝕・高硬度絶縁材料１８の設置、図１０に示した高圧反応ガス供給口２に対する多孔質材料の設置、図１２に示した多回転軸且つ回転数をもつ多数試料固定用試料台Ｔ１１によるバッチ処理方式、試料台Ｔや試料固定部Ｆなどの構成などに関する特徴は、本実施形態の試料浮上型高圧浮上電極Ｈ２に対しても同様に適用することができる。
【０１８６】
或いは、図１４のように試料浮上型高圧浮上電極Ｈ２においても、高圧反応ガス供給口２及び反応生成物排気口４の位置及び数量は１つに限定されず、試料台Ｔに、或いは高圧浮上電極Ｈ２及び試料台Ｔの両方に、設置することも可能である。
【０１８７】
図１５は、試料浮上型高圧浮上電極Ｈ２において、浮上体を、図１３に示した浮上試料Ａを固定した試料台Ｔでなく、浮上試料Ａのみとした構成である。
【０１８８】
図１５におけるＹ１１は、浮上試料Ａを拘束或いは走査させ得る浮上試料拘束走査機構であり、直接前記走査ワイヤ或いはベルトＹを浮上試料Ａに接続させること無く、浮上試料Ａの浮上方向とは別に側面より浮上試料を押すことにより、浮上試料Ａを走査させる機構である。
【０１８９】
この構成によれば、電極浮上型高圧浮上電極Ｈ１或いは試料浮上型高圧浮上電極Ｈ２における試料のチャッキング時間を省略することができる。従って、このような浮上試料拘束走査機構により、１方向に浮上試料を移動させて、流れ作業的に成膜し、その後に試料搬送を行うことにより、プロセスの生産性を向上させることができる。
【０１９０】
（第３の実施形態）
次に、導波管を電力伝達線路に用いた電極浮上型高圧浮上電極Ｈ３による、本発明の第３の実施形態について説明する。
【０１９１】
導波管を電力伝達線路に用いる場合、電力伝送線路は直流及び周波数の低い交流を伝送することができない。従って、電源Ｇとしては、少なくとも周波数１０ＭＨｚ〜１ＧＨｚの高周波、或いは１ＧＨｚ以上のマイクロ波電源Ｇ１１を用いる。
【０１９２】
図１６は、導波管を前記電力伝送線路に用いた電極浮上型高圧浮上電極Ｈ３の断面図であり、図１７は、電極Ｈ３を別の方向より見た部分断面図、図１８Ａ及び図１８Ｂは、それぞれ電極Ｈ３の下方斜面図及び上方斜面図である。
【０１９３】
図１６において、Ｈ３は導波管を前記電力伝送線路に用いた電極浮上型高圧浮上電極、Ｐは局所高圧プラズマ、２４はマイクロ波を印加することによって高電界を発生し、電極Ｈ３−試料Ｊの間の微小間隔Ｄに局所高圧プラズマＰを発生させる導波管の開放端、２１はマイクロ波電源Ｇ１１より供給されたマイクロ波を必要に応じて昇圧・マッチングする共振・整合装置Ｍから、高圧浮上電極Ｈ３にマイクロ波を伝送するフレキシブル導波管、２２はフレキシブル導波管２１より電極Ｈ３の試料対向部分２８に位置する導波管開放端２４へマイクロ波を伝達する電極内導波管、２３は、電極内導波管２２の内部空間と、電極Ｈ３−試料Ｊの間の微小間隔Ｄの高圧反応ガス領域とを分離する絶縁体、２０は、高圧反応ガス供給口として機能し、形状がスリット形状である高圧反応ガス供給スリットである。
【０１９４】
また、図１７において、Ｔ１２は、凹状形状をなし、凹部内側底面において試料Ｊを固定し、凹部内側側壁において電極Ｈ３の移動を拘束する凹状試料台である。２５は高圧気体供給口であり、凹状試料台Ｔ１２の内側側壁に設けられ、該供給口より噴出する高圧気体により、電極Ｈ３に接触すること無く、電極Ｈ３の運動方向を１方向に拘束する。２６は、高圧気体供給口２５に、図示しない高圧気体供給装置より高圧気体を輸送する高圧気体供給経路である。
【０１９５】
図１８Ａにおいて、２７は、高圧反応ガス供給スリット２０から、反応ガス排気口４へ、或いは電極Ｈ３周囲の気体雰囲気へ向かって、電極Ｈ３−試料Ｊの間の微小間隔Ｄを流れる試料表面に沿った流れである。
【０１９６】
また、これらの各図における試料Ｊ、試料固定部Ｆ、高圧反応ガス供給経路１、反応生成物排気経路３、反応生成物排気口４については、内側電極５、外側電極６及び絶縁体１１によって電極内電力伝送線路を構成する高圧浮上電極Ｈ１或いはＨ２と同様の構成である。また、図示しない走査ステージＳ、反応容器Ｃ、電源Ｇ、電力伝達線路Ｋ、共振・整合装置Ｍ、高圧反応ガス供給装置Ｒ、排気装置Ｅ、高圧浮上電極走査装置Ｕ、制御装置Ｎも、高圧浮上電極Ｈ１或いはＨ２と同様の構成となる。但し、電源Ｇに代えて、高周波或いはマイクロ波電源Ｇ１１を用いる。
【０１９７】
以下に、導波管を電力伝送線路に用いた電極浮上型高圧浮上電極Ｈ３の構成、高圧浮上電極Ｈ３の浮上方式、高圧浮上電極Ｈ３の成膜方式、導波管を電力伝送線路に用いることの効果、及びマイクロ波電源Ｇ１１を用いることの効果について、順に説明する。
【０１９８】
まず、導波管を電力伝送線路に用いた電極浮上型高圧浮上電極Ｈ３について、あらためて説明すると、図１８Ａ及び図１８Ｂに示されるように、この電極Ｈ３は、金属立方体において、試料Ｊと対向する一面を高精度に平坦化し、その面を電極浮上型高圧浮上電極Ｈ３の試料対向部分２８とする。更に、前記金属立方体内部にマイクロ波電力を伝達し得る電極内導波管２２を設け、且つ試料対向部分２８内の所望の位置に向かって、導波管２２を開放終端化させる。開放終端化した電極内導波管２２の内部空間を絶縁体２３によって塞ぎ、電極浮上型高圧浮上電極Ｈ３の周囲の気体雰囲気より分離する。この電極内導波管２２の、試料対向部分２８において開放終端化された部分を、導波管開放端２４と呼ぶ。電極内導波管２２に、導波管開放端２４とは反対方向からフレキシブル導波管２１を接続することにより、電源Ｇ１１より発生したマイクロ波電力を、電極浮上型高圧浮上電極Ｈ３内の電極内導波管２２、更には導波管開放端２４にまで伝達させる。これによって、該導波管開放端２４の位置に局所高圧プラズマＰを発生させる。
【０１９９】
ここで、絶縁体２３は、高硬度で且つ局所高圧プラズマＰに対して耐食性を持つ材質から構成されることが望ましく、そのような材質としては、例えば高純度アルミナや窒化珪素などが挙げられる。更に、場合に応じて、成膜材質を構成する元素を少なくとも１種類以上含む材料、例えばＳｉ膜を成膜する場合には、絶縁体２３に窒化珪素を用いて、膜中への不純物混入を低減させることが望ましい。絶縁体２３の設置後も、試料対向部分２８が高精度な平坦面となる程度まで、再度平坦化加工することが望ましい。更に、試料対向部分２８に高圧反応ガスを噴出するための高圧反応ガス供給スリット２０を開口させ、その位置は、導波管開放端２４より離れた位置とする。高圧反応ガス供給スリット２０に高圧反応ガス供給装置Ｒから高圧反応ガス供給経路１を通じて高圧反応ガスを供給し、高圧反応ガス供給スリット２０から、高圧反応ガスを噴出させる。更に、試料対向部分２８にあって、且つ前記高圧反応ガス供給スリット２０と導波管開放端２４とに挟まれた位置に、反応生成物排気経路３を通じて排気装置Ｅに接続され、且つプラズマ中の反応によって発生した反応生成物を排気する反応生成物排気口４を設ける。
【０２００】
ここで、図１８Ａ及び図１８Ｂに示されるように、反応生成物排気口４及び導波管開放端２４は、その形状を幅の広いスリット状とし、スリット２０、反応生成物排気口４、及び導波管開放端２４は、互いに平行関係になる様に設置する。
【０２０１】
次に、高圧浮上電極Ｈ３の浮上方式について説明する。
【０２０２】
図１７に示されるように、高圧浮上電極Ｈ３を、試料Ｊを固定した凹状試料台Ｔ１２の凹部に、両者を非接触状態に保った状態ではめ込む。高圧反応ガス供給装置Ｒより、高圧反応ガス供給経路１を通じて高圧反応ガス供給スリット２０より高圧反応ガスを噴出させることにより、高圧反応ガスと反応容器Ｃ内の気体雰囲気との差圧により、高圧浮上電極Ｈ３を試料Ｊに対して微小間隔Ｄだけ浮上させる。従って、凹状試料台Ｔ１２及び試料Ｊと高圧浮上電極Ｈ３の試料対向部分２８は、非接触状態を保つ。更に、凹状試料台Ｔ１２の内側凹部側面６３と該内側側面に対向する高圧浮上電極Ｈ３の側面６２は、高精度に平坦化されている。更に、凹状試料台Ｔ１２の凹部の幅Ｑ１２は、高圧浮上電極Ｈ３の幅Ｑ１１より僅かに大きく、図示しない高圧気体供給装置より高圧気体供給経路２６を通じて高圧気体供給口２５より高圧気体を噴出させることにより、凹状試料台Ｔ１２の内側凹部側面６３と該内側側面に対向する高圧浮上電極Ｈ３の側面６２は非接触状態を保ち、更に高圧浮上電極Ｈ３の運動方向を１方向に限定する。つまり、導波管を電力伝送線路として用いた電極浮上型高圧浮上電極Ｈ３は、電力伝送線路として電極内導波管２２を採用しただけであるため、その浮上方式では、第１の実施形態における電極浮上型高圧浮上電極Ｈ１と同じく、高圧反応ガス供給スリット２０より供給された反応ガスの高圧力Ｐ０と、排気装置Ｅによって排気された反応容器Ｃ内の低圧或いは真空雰囲気圧力Ｐ１との差圧によって、微小間隔Ｄだけ浮上する。高圧反応ガス供給口をスリット状にし、更にスリット２０及び反応生成物排気口４を互いに平行関係になる様に設置することにより、供給スリット２０から反応ガス排気口４へ向かう高圧反応ガスの流れにおいて、スリット２０の長手方向の流速分布を均一化させることができる。このように流速分布を均一化させることにより、導波管開放端２４に発生する局所高圧プラズマＰにおける前記成膜速度分布を、均一化させることができる。
【０２０３】
次に、本実施形態の電極Ｈ３による成膜方法を説明する。
【０２０４】
マイクロ波電源Ｇ１１より発生したマイクロ波電力は、共振・整合装置Ｍとフレキシブル導波管２１、更に電極内導波管２２を通じて、高圧浮上電極Ｈ３の試料対向部２８に設けられた導波管開放端２４に達する。導波管開放端２４に達したマイクロ波電力は、電極Ｈ３−試料Ｊの間の微小間隔Ｄ中の高圧反応ガスに向かって放射される。これによって高圧反応ガスは解離し、反応ガスに基づく局所高圧プラズマＰを発生させる。更に、プラズマＰ中に発生した反応ガスに基づく活性種により、試料Ｊの局所高圧プラズマＰの直下の成膜を行う。
【０２０５】
ここで、導波管２２の断面形状は、マイクロ波電源Ｇ１１の周波数と、試料Ｊと目的とする成膜特性、成膜領域より決定される。
【０２０６】
更に、高圧反応ガス供給スリット２０より供給された反応ガスは、反応容器Ｃ内の低圧或いは真空雰囲気、及び前記反応ガス排気口４へ向かって、電極Ｈ３の浮上によって形成された電極Ｈ３―被加工物Ｊの間の微小間隔Ｄ中を、試料表面に沿った流れ２７となって移動する。また、導波管を用いた電力伝送線路開放端２４を、試料対向部２８中で且つ高圧反応ガス供給スリット２０より離れた反応ガス排気口４で挟まれる位置に設けることによって、高圧反応ガスの試料表面に沿った流れ中に局所高圧プラズマＰを形成して、よどみの無い反応ガスの流れ場の中で、表面に均一な成膜を行う。
【０２０７】
次に、導波管を電力伝送線路に用いることの効果を説明する。
【０２０８】
電極Ｈ１及びＨ２のような内側電極５と外側電極６を用いて電力伝送線路を構成する実施形態においては、電源Ｇに、マイクロ波電源Ｇ１１のみでなく、直流からマイクロ波電源まで、全ての周波数の電力を用いることができる。しかし、内側電極５−外側電極６の間の絶縁、及び内側電極５と外側電極６とによって囲まれる電力伝達部分と前記電極―被加工物間の微小間隔Ｄ中の反応ガス領域との分離を行うための絶縁体１１は、内側電極５の外径及び外側電極６の内径に対して、隙間なく取り付けられていることが必要である。その場合、発生した局所高圧プラズマＰから発生する熱によって、内側電極５及び外側電極６が熱変形し、特に内側電極５の熱膨張によって絶縁体１１の破損を引き起こす可能性が存在する。従って、外側電極６及び内側電極５の冷却を行うが、現実には、この様に複雑な構造体である高圧浮上電極Ｈ１或いはＨ２を製作し、更に電極Ｈ１或いはＨ２の全体を均一に冷却する機構を設けることは、非常に困難である。
【０２０９】
しかし、本実施形態においては、電力伝送線路に導波管を用いることにより、電圧印加する内側電極５と、電界を閉じ込める外側電極６との区別が無く、マイクロ波を伝播させる場合において、高圧浮上電極内部の電力伝送線路及び電極内冷却経路の製作を容易にする。また、金属構造体が絶縁体２３を取り囲む構造となり、金属の熱膨張係数と絶縁体の熱膨張係数とでは金属の熱膨張係数の方が一般的に大きいことから、金属体の熱膨張による絶縁体２３の破損が起こり難い。
【０２１０】
また、電源としてマイクロ波電源Ｇ１１を用いることにより得られる効果について説明すると、以下の表５は、最大電界強度Ｅ０及び周波数ｆで周期的に変化する振動電界Ｅ＝Ｅ０・ｓｉｎ（２πｆｔ）の中（但しｔは時間）において、真空中で各種荷電粒子（電荷量ｅ、質量ｍ）が振動する時の振動振幅Ｌ＝（ｅ・Ｅ０／４ｍπ^２ｆ^２）の値を示した表である。但し、電界強度を１．０×１０^６［Ｖ／ｍ］としている。
【０２１１】
【表５】

【０２１２】
また、図１９（ａ）は、荷電粒子２９の前記振動電界Ｅ（図１９（ｂ）参照）による振動振幅Ｌを示す概念図である。
【０２１３】
表５に示されるように、振動電界Ｅの振動振幅Ｌは、周波数を向上させるにしたがって小さくなる。微小間隔Ｄは１μｍ〜数百μｍ程度の狭ギャップであるが、局所高圧プラズマＰを発生させる電源に周波数が１ＭＨｚ程度である高周波電源を用いると、それによる振動振幅ＬはＨｅイオンの場合で０．６０７［ｍ］と非常に大きくなる。この結果、荷電粒子を狭ギャップ中に捕捉することができず、結果として荷電粒子が試料表面及び成膜中の膜表面に衝突して膜に損傷を与え、欠陥密度の大きい膜質となる。
【０２１４】
しかし、電極−試料の微小間隔Ｄが数百μｍ程度の時には、局所高圧プラズマＰを発生させる電源に最低１０ＭＨｚ以上の高周波を用いる一方で、微小間隔Ｄが数十μｍ程度の時には周波数１ＧＨｚ以上のマイクロ波を用いることにより、荷電粒子が電極−試料間の微小間隔Ｄ中に確実に捕捉されて、膜に損傷を与えない低損傷な成膜を実現することができる。
【０２１５】
図１７に示されるように、試料Ｊと高圧浮上電極Ｈ３との相対的な移動にあたっては、凹状試料台Ｔ１２の内側底部に試料Ｊを試料固定部Ｆによって固定し、試料台Ｔ１２の内側側面６３に設置された高圧気体供給口２５より噴出した高圧気体により、エアスライド的に摺動部を用いること無く非接触に、高圧浮上電極Ｈ３の走査方向を試料Ｊに水平な方向のみに限定する。更に、試料Ｊに水平な方向の走査は、高圧浮上電極Ｈ３に接続された走査ワイヤ或いはベルト９を図示しない駆動モータ１０に接続し、この駆動モータを回転させることによって行う。
【０２１６】
高圧気体供給口２５より噴出させる高圧気体は、試料Ｊの成膜に用いる高圧反応ガスに限定せず、絶縁性の高いガスや希ガス、或いは空気など、目的に応じて変化させる。
【０２１７】
（第４の実施形態）
次に、本発明の第４の実施形態について説明する。
【０２１８】
図２０Ａ、図２０Ｂ、及び図２０Ｃは、それぞれ、導波管を電力伝送線路に用いた試料浮上型高圧浮上電極の断面図、正面図、及び上面図である。また、これらの図中で、Ｈ４は、導波管を電力伝送線路に用いた試料浮上型高圧浮上電極、３０は突起のついた浮上試料送りベルト、３１は送りベルトの突起、３２は浮上試料送りモータである。
【０２１９】
導波管を電力伝送線路に用いた試料浮上型高圧力浮上電極Ｈ４は、先の実施形態で説明した導波管を電力伝送線路に用いた電極浮上型高圧浮上電極Ｈ３と同様に、導波管によってマイクロ波を伝達し、電極Ｈ４の試料対向部に設けられた導波管開放端２４において局所高圧プラズマＰを発生させる。そして、微小間隔Ｄ中に供給された高圧反応ガスを分解し、反応ガスに基づく活性種を発生して浮上試料Ａの表面の成膜を行う。更に、電極Ｈ４−試料Ａの間の微小間隔Ｄ中の反応ガスの試料表面に沿った流れにより、試料Ａの表面に均一に成膜を行なう。試料浮上型高圧浮上電極Ｈ２と同様に、電極浮上型高圧浮上電極Ｈ１、及び図１４の試料浮上型高圧浮上電極における試料Ｊ及びＡのチャッキング時間を省略することができるので、流れ作業的に加工・試料搬送を行うことにより、プロセスの生産性を更に向上させることができる。
【０２２０】
導波管を電力伝送線路に用いた試料浮上型高圧浮上電極Ｈ４において、図２０Ａ、図２０Ｂ、及び図２０Ｃに図示しない装置全体の構成や、試料の浮上原理、プラズマ発生方式、及び局所プラズマ中における成膜現象、高成膜速度、膜質の向上及び試料の成膜後表面の清浄化を同時に実現する原理及び方式については、先に説明した電極浮上型高圧浮上電極Ｈ１と同様である。
【０２２１】
また、図示しないが、図１４のように試料台に前記試料を固定し、試料台と共に試料を浮上させる方式を実施することも可能である。
【０２２２】
浮上試料の走査は、図２０Ｃに示すような、両端を浮上試料送りモータ３２によって拘束・回転される突起３１のついた浮上試料送りベルト３０によって、突起３１で試料を固定しながら両端のモータ３２を回転させることによって、試料を１方向に送ったり往復走査させたりする機構を用いることもできる。
【０２２３】
（第５の実施形態）
次に、本発明の第５の実施形態について説明する。
【０２２４】
図２１は、被成膜表面の形状が球面である試料に成膜を行う高圧浮上電極の部分断面図である。図２１において、Ｈ５は、試料対向部に球面形状をもつ高圧浮上電極、Ｔ１３は球面試料固定用試料台、Ｂは被成膜表面の形状が球面である試料、６０は、球面試料固定用試料台Ｔ１３の電極対向面、６１は、高圧浮上電極Ｈ５の試料対向部分である。
【０２２５】
被成膜表面の形状が球面である試料Ｂに成膜を行う場合、球面試料固定用試料台Ｔ１３の電極対向面６０を球面とし、その半径を試料Ｂの形状の球面半径に一致させて、試料Ｂの成膜面の球面が試料台Ｔ１３の電極対向面６０の球面に段差なく重なる様に設置する。一方、高圧浮上電極Ｈ５の試料対向部分６１の形状を同じく球状とし、その半径を試料Ｂの球面半径と同じ或いはそれ以上とする。このような状態で、高圧浮上電極Ｈ５の試料対向部分６１と試料Ｂの球面とを対向させ、多孔質材料１９を用いた高圧反応ガス供給口より供給した高圧反応ガスと反応容器内の低圧及び真空雰囲気との差圧により、高圧浮上電極Ｈ５を、試料Ｂの表面より微小間隔Ｄだけ浮上させる。
【０２２６】
図示しないが、同様に高圧反応ガス供給口より供給した高圧反応ガスと反応容器内の低圧及び真空雰囲気との差圧により、試料Ｂを高圧浮上電極Ｈ５より微小間隔Ｄだけ浮上させることも可能である。
【０２２７】
プラズマの発生は、高圧浮上電極Ｈ１と同様に、電極Ｈ５の試料対向面に設置した電力伝送線路開放端７に、図示しない電源Ｇより発生した直流或いは交流電圧を伝達し、高圧反応ガスの供給された電極Ｈ５−試料Ｂの間の微小間隔Ｄに強電界を発生させることによって局所高圧プラズマＰを発生させ、反応ガスに基づく活性種によって試料Ｂに成膜を行う。
【０２２８】
図２１の構成において、電力伝送線路は内側電極５及び外側電極６によって構成されており、電源Ｇより発生した直流或いは交流を、電力伝送線路開放端７、更に局所高圧プラズマＰまで、伝達している。或いは、電源がマイクロ波電源である場合は、例えば、先の実施形態に関連して図１６に示したように導波管を用いてマイクロ波を伝達させ、更に、図１８Ａの試料対向部分２８を、高圧浮上電極Ｈ５の試料対向部分６１に示されるような球面とし、試料と対向する部分に同様に設置した導波管開放端に強電界を発生させて局所高圧プラズマＰを発生させ、球面試料Ｂに成膜すればよい。
【０２２９】
電極浮上型高圧浮上電極Ｈ１、試料浮上型高圧浮上電極Ｈ２、Ｈ３、導波管をマイクロ波伝送線路として用いた高圧浮上電極Ｈ４で示した前記高圧反応ガス供給口形状及び位置、反応生成物排気口形状及び位置、マイクロ波開放端形状及び位置、高圧浮上電極形状及び試料対向部耐蝕・高硬度絶縁膜形成及び試料対向部耐蝕・高硬度絶縁材料設置、試料台、試料固定部などに関する先述の特徴は、本実施形態のように試料の成膜面形状が球面である場合の高圧浮上電極Ｈ５にも、同様に適用することができる。
【０２３０】
上記において、本発明の各実施形態の説明では、本発明によって成膜を行なう場合を中心として述べたが、表面の改質処理を行なう場合においても、同様に適用できる。
【０２３１】
【発明の効果】
以上に説明したように、本発明によれば、所望の気体雰囲気内に試料及び電力を印加する電極を対向させて配置し、電力印加によって局所的にプラズマを発生させる。このとき、局所的なプラズマ発生部のみを高圧力に維持することにより、試料表面に高能率に表面処理（例えば、成膜或いは表面処理）を行う。同時に、所望の気体雰囲気圧力を少なくとも前記の局所高圧プラズマ発生部より低圧に、或いは真空に維持することにより、反応生成物が凝縮せず且つ試料表面に再付着することもなく、良質な膜形成或いは表面処理を行なうことができる。また、プラズマ発生領域を、電極−試料間隔の反応ガス供給口近傍の反応ガス噴出領域以外の場所であって、反応ガスの試料表面に沿った流れが形成される領域中のみに限定することにより、成膜処理時には、反応ガス噴出領域の直下に成膜量分布が形成されること無く、或いは、表面処理時には、反応ガス噴出領域の直下に処理層厚さ分布が形成されること無く、試料表面の表面処理（成膜或いは表面改質）を行なうことができる。
【０２３２】
更に、本発明によれば、局所的に形成した高圧反応ガス領域においてプラズマを発生させることにより、試料に高速に成膜することができ、同時に前記プラズマの発生している局所的に高圧力となった領域以外が前記高圧反応ガス領域より低圧に維持されることにより、試料周辺雰囲気における反応生成物の凝縮が少なく、良質な膜形成を行なうことができ、また更に膜表面を清浄に保つことができる。
【０２３３】
また、本発明によれば、試料を配した気体雰囲気の圧力ｐ０に対する、前記低コンダクタンス流路部分に局所的に維持された高圧気体雰囲気中のプラズマ発生する部分の圧力ｐｘの比ｐｘ／ｐ０をｐｘ／ｐ０＞１とすることにより、プラズマ部において高密度活性種を発生して高成膜速度を達成する。同時に、プラズマ部より周囲雰囲気の圧力が低いことから、試料周辺雰囲気における反応生成物の凝縮を更に少なくし、良質な膜形成を行なうと同時に、膜表面を清浄に保つことができる。
【０２３４】
また、本発明によれば、プラズマの発生する局所的に高圧力となった部分以外の領域を、圧力１気圧以下とすることにより、反応ガスが大気に拡散し難くなって、装置の安全性を高めることができる。
【０２３５】
また、本発明によれば、プラズマの発生する局所的に高圧力となった部分以外の領域を、更に真空雰囲気とすることにより、被加工物周辺雰囲気における反応生成物の粒径、及び数の絶対値を低くすることができ、良質な膜形成を行なうことができるとともに、更に膜表面を更に清浄に保つことができる。同時に、試料の大気雰囲気への搬出時のパージに際して、雰囲気が真空に保たれているため、反応ガスをその都度排気する必要が無く、装置のスループットを向上させることができる。
【０２３６】
また、本発明によれば、低コンダクタンス流路部に局所的に形成された高圧反応ガス領域中の、更に特定領域において局所的な高圧プラズマを発生させることにより、所望の位置に局所的に成膜を行なうことができる。
【０２３７】
また、前記の局所高圧プラズマを発生させて試料表面に成膜を行なう領域を、反応ガスを供給する部分より離れた位置に設けることにより、反応ガス供給部分直下における膜厚分布形成を防ぎ、均一な成膜を行なうことができる。
【０２３８】
更に、試料に応じた形状を持ち、更に高圧反応ガス供給口を少なくとも何れか一方に持つ電極及び試料台において、電極と試料とを微小間隔を隔てて設置することにより、電極を、供給口から気体雰囲気への気体流路の低コンダクタンス部分を形成する壁面として、先に述べた高圧反応ガス領域を局所的に形成することができる。更に、電極に電力を印加して、低コンダクタンスにより局所的に高圧反応ガスとなった電極−試料間の微小間隔にプラズマを発生させれば、試料に対して高速に且つ良質な成膜を行なうことができ、更に膜表面を清浄に維持することができる。
【０２３９】
また、供給口より供給した高圧反応ガスの圧力によって局所的に形成された高圧力の反応ガス領域と気体雰囲気圧力との間の差圧により、電極を試料に対して、或いは試料を電極に対して、微小間隔を隔てて浮上させることにより、プラズマの熱による電極や試料の変形、或いはプラズマを発生させる電界や腐食性ガスの存在により微小間隔の測定・制御が困難な環境においても、低コンダクタンスな気体流路を安定して広面積に微小間隙を形成することができる。また、電極を試料に対して傾くこと無く配置することができ、反応ガスの流量分布を均一にすることにより、膜厚均一性を向上させることができる。
【０２４０】
また、更に磁性体或いは磁力発生機構を電極或いは試料台の少なくとも何れか一方に持ち、この磁性体或いは磁力発生機構より発生した磁力により、電極を試料に対して、或いは試料を電極に対して、微小間隔を隔てて浮上させることにより、低コンダクタンスな気体流路を安定して広面積に形成することができる。更に、電極或いは試料を浮上させる力に新たに設けた磁力発生機構或いは磁性体から発生した磁力を用いることにより、反応ガス圧力範囲を広く設定でき、電極重量でなく、目的とする成膜特性によって、反応ガスの供給圧力を決定できる。
【０２４１】
また、更に前記電極内に電力伝達線路を設けて、試料と対向する部分にこの電力伝達線路開放端を設けることにより、電極に印加された電力を電力伝送線路開放端に伝送させ、開放端の近傍のみに局所的にプラズマを発生させることができる。また、電力伝送線路がプラズマによって終端化されていることにより、試料を全面成膜するために電極と試料とを相対的に移動させた場合においても、電力投入機構部分の等価回路が変化しない。この結果、プラズマに対する影響が少なく、広い面積に更に均一に成膜を行なうことができる。
【０２４２】
また、プラズマを発生させる電力をマイクロ波電力とすることにより、電極と試料との間の微小間隔に発生したプラズマ中の荷電粒子を微小間隔にて確実に捕捉し、試料表面及び形成された膜に与える損傷を更に低減させることができる。また、同時に、微小間隔に保たれた電極―試料の間にプラズマを発生させることができる。
【０２４３】
また、電極内の電力伝送線路を導波管とすることにより、電極の構成を簡略化でき、プラズマの熱による電極の変形による電極自体の破損を防止することにより、装置の信頼性を向上させることができると共に、部品形状の簡略化により装置コストを低減させることができる。
【０２４４】
電極或いは試料台に、プラズマの発生する微小間隔に向かって開口する反応生成物排気口を設け、この排気口よりプラズマにおいて発生した反応生成物を即座に排気することによって、試料に良質な膜を形成することができ、また膜表面を更に清浄に維持することができる。
【０２４５】
また、試料に対して、試料と対向する部分の形状に少なくとも、試料表面に対して相似形状を含む形状をもつ電極を用いて、電極−試料間の微小間隔内の反応ガス供給口の高圧力部から電極周囲の気体雰囲気或いは反応ガス排気口へ向かう試料表面に沿う流れ中において局所的なプラズマを発生させ、このプラズマによって生じた反応ガスに基づく活性種の試料表面に沿うよどみの無い流れにより、試料に均一に成膜を行なうことができる。
【０２４６】
また、電極及び試料台の少なくとも何れか一方に、使用する電源の周波数の電磁波に対して大きな吸収係数を持つ電力吸収体を、反応ガス供給部から周囲の気体雰囲気へと流れる低コンダクタンス流路のうちの、局所高圧プラズマが発生する領域より低圧力側に設けることにより、局所高圧プラズマで消費されず通過した電磁波を吸収し、局所的な高圧雰囲気の外部における、低圧な気体雰囲気中にプラズマが発生することを防ぐことができる。
【０２４７】
また、プラズマを発生させる電極と試料とを相対的に移動させることにより、試料に対して大面積に成膜を行なうことができ、また走査速度を制御することにより、所望の膜厚分布に成膜することができる。
【０２４８】
また、反応容器内の気体雰囲気を排気し、更に処理後に再び反応ガス或いは反応容器内の気体雰囲気として供給することにより、反応ガス及び雰囲気ガスを無駄にすることが無く、成膜コストを低減させることができる。
【０２４９】
なお、電極には、直流から低周波、高周波、マイクロ波の広い範囲の電力を印加することが可能である。
【０２５０】
また、上記の本発明の効果は、本発明によって成膜を行なう場合について述べたが、表面処理を行なう場合についても、同様の効果を得ることができる。
【図面の簡単な説明】
【図１】本発明の装置の全体概念図である。
【図２】電極浮上型高圧浮上電極Ｈ１の断面図である。
【図３】電極浮上型高圧浮上電極Ｈ１の試料対向部分を表した下方斜面図である。
【図４】試料Ｊと試料台Ｔとの段差ｔを示す部分断面図である。
【図５】（ａ）は、電極浮上型高圧浮上電極Ｈ１−試料Ｊの間の微小間隔Ｄの近傍の模式的断面図であり、（ｂ）は、上記の微小間隔Ｄ中の高圧反応ガスの圧力分布を示す模式図である。
【図６】電極浮上型高圧力浮上電極Ｈ１の試料Ｊと対向する部分に設けられた電力伝送線路開放端における局所領域プラズマＰの発生を示す概略図である。
【図７】（ａ）は、高圧反応ガス供給口２の近傍における構成を模式的に示す断面図であり、（ｂ）は、（ａ）の構成を利用して高圧反応ガス供給口２を含む近傍に局所高圧プラズマＰを発生させる場合に、供給口２の直下に形成される膜厚分布を示す断面図であり、（ｃ）は、上記に際して微小間隙Ｄに発生するガス流の状態を模式的に示す図である。
【図８】（ａ）は、高圧反応ガス供給口２から離れた位置に電力伝送線路開放端７を設置する場合の、高圧反応ガス供給口２及び線路開放端７の近傍における構成を模式的に示す断面図であり、（ｂ）は、（ａ）の構成を利用して高圧反応ガス供給口２を含む近傍に局所高圧プラズマＰを発生させる場合に、供給口２の直下に形成される膜厚分布を示す断面図であり、（ｃ）は、上記に際して微小間隙Ｄに発生するガス流の状態を模式的に示す図である。
【図９】高精度平坦化耐蝕・高硬度絶縁体を試料対向部分に用いた電極浮上型高圧浮上電極の断面図である。
【図１０】高圧反応ガス供給口に多孔質材料を用いた電極浮上型高圧浮上電極の断面図である。
【図１１】試料台Ｔに高圧反応ガス供給口を設置した電極浮上型高圧浮上電極の断面図である。
【図１２】多回転軸及び回転数をもつ試料多数固定用試料台Ｔ１１を用いたバッチ処理を示す概略図である。
【図１３】試料浮上型高圧浮上電極Ｈ２の概略断面図である。
【図１４】試料台Ｔに高圧反応ガス供給口を設置した試料浮上型高圧浮上電極Ｈ２の断面図である。
【図１５】試料のみを浮上させた試料浮上型高圧浮上電極Ｈ２の概略断面図である。
【図１６】導波管を電力伝送線路に用いた電極浮上型高圧浮上電極Ｈ３の断面図である。
【図１７】導波管を電力伝送線路に用いた電極浮上型高圧浮上電極Ｈ３を別の方向より見た部分断面図である。
【図１８Ａ】導波管を電力伝送線路に用いた電極浮上型高圧浮上電極Ｈ３の下方斜面図である。
【図１８Ｂ】導波管を電力伝送線路に用いた電極浮上型高圧浮上電極Ｈ３の上方斜面図である。
【図１９】（ａ）は、荷電粒子の振動電界による振動振幅を示す概念図であり、（ｂ）は、（ａ）の振動を生じさせる振動電界を示す模式図である。
【図２０Ａ】導波管を電力伝送線路に用いた試料浮上型高圧浮上電極Ｈ４の断面図である。
【図２０Ｂ】導波管を電力伝送線路に用いた試料浮上型高圧浮上電極Ｈ４の正面図である。
【図２０Ｃ】導波管を電力伝送線路に用いた試料浮上型高圧浮上電極Ｈ４の上面図である。
【図２１】試料仕上げ形状が球面である試料の表面平滑化及び形状成膜を行う高圧浮上電極Ｈ５の部分断面図である。
【図２２】円板Ｈ０による気体の流れ場の形成を示す概略図である。
【図２３】図２２の構成において、円板−被成膜試料間に円筒座標軸を設定した図である。
【図２４】ある従来技術によるプラズマを用いた表面処理装置の構成を模式的に示す断面図である。
【図２５】原料ガス供給口直下に形成されると考えられる薄膜の膜厚分布を模式的に示す図である。
【符号の説明】
Ａ 浮上試料
Ｂ 成膜面形状が球面である試料
Ｃ 反応容器
Ｄ 微小間隔
Ｅ 排気装置
Ｆ 試料固定部
Ｇ 電源
Ｇ１１ マイクロ波電源
Ｈ０ 円板
Ｈ１ 電極浮上型高圧浮上電極
Ｈ２ 試料浮上型高圧浮上電極
Ｈ３ 導波管を電力伝送線路に用いた電極浮上型高圧浮上電極
Ｈ４ 導波管を電力伝送線路に用いた試料浮上型高圧浮上電極
Ｈ５ 試料対向部に球面形状をもつ高圧浮上電極
Ｉ フレキシブル電力伝送線路
Ｊ 試料
Ｋ 電力伝送線路
Ｌ 荷電粒子の振動電界による振動振幅
Ｍ 共振・整合装置
Ｎ 制御装置
Ｒ 高圧反応ガス供給装置
Ｓ 走査ステージ
Ｔ 試料台
Ｔ１１ 試料多数固定用試料台
Ｔ１２ 凹状試料台
Ｔ１３ 球面試料固定用試料台
Ｕ 電極走査装置
Ｙ 浮上試料走査ワイヤ
Ｙ１１ 浮上試料拘束走査機構
θ 試料台Ｔの持つ回転機構
θ１ 試料多数固定用試料台Ｔ１１の持つ回転機構
１ 高圧反応ガス供給経路
１１１ バッファ部
２ 高圧力反応ガス供給口
３ 反応生成物排気経路
４ 反応ガス排気口
５ 内側電極
６ 外側電極
７ 電力伝送線路開放端
８ コネクタ
９ 走査ワイヤ（ベルト）
１０ 駆動モータ
１１ 絶縁体
１２ 電極浮上型高圧浮上電極Ｈ１の試料対向部分
１６１１ 高圧反応ガス供給口２から噴出する高圧反応ガス噴出流
１６１２ 微小間隔Ｄ中で試料表面に沿う流れとなった高圧反応ガス流
１６１３ 供給口２の近傍で乱流になった反応ガスの流速分布
１６１４ 供給口２から離れてせん断流へ変化する反応ガスの流速分布
１６１５ 供給口２から十分に離れてせん断流になった反応ガスの流速分布
１７１１ 高圧反応ガス供給口２を含む近傍に局所高圧プラズマＰを発生させる場合に供給口２の直下に形成される成膜量分布
１７１２ 高圧反応ガス供給口２から離れた位置に電力伝送線路開放端７を設置して局所高圧プラズマＰを発生させる場合に局所高圧プラズマＰの直下に形成される成膜量分布
１８ 高精度平坦化耐蝕・高硬度絶縁体
１９ 多孔質金属或いは多孔質絶縁体材料
２０ 高圧反応ガス供給スリット
２１ フレキシブル導波管
２２ 電極内導波管
２３ 絶縁体
２４ 導波管開放端
２５ 高圧気体供給口
２６ 高圧気体供給経路
２７ 試料の表面に沿った流れ
２８ 導波管を電力伝送線路に用いた電極浮上型高圧力浮上電極Ｈ３の試料対向部分
２９ 荷電粒子
３０ 突起のついた浮上試料送りベルト
３１ 送りベルトの突起
３２ 浮上試料送りモータ
６０ 球面試料固定用試料台Ｔ１３の電極対向面
６１ 高圧浮上電極Ｈ５の試料対向部分
６２ 高圧浮上電極Ｈ３の側面
６３ 凹状試料台Ｔ１２の内側凹部側面
１０１ 高圧気体供給路
２４０ｐ 高圧プラズマ
２４０ｇ 基板間距離
２４１ 成膜室
２４２ 非接地基板
２４３ 接地電極
２４４ 多孔板高抵抗体
２４５ 試料基板
２４６ ガス導入口
２４７ ＲＦ電極
２４８ ヒータ
２４９ ガス排出口
２５０ ガス供給口
２５１ 前記試料基板に衝突する原料ガスの流れ
２５２ 薄膜
２５３ 原料ガス供給口直下に形成される薄膜の凸部[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a surface treatment method and a surface treatment apparatus using plasma, and more particularly, to film formation or surface modification in a multilayer structure of various devices such as semiconductor devices and liquid crystal devices, and film formation or surface treatment of various functional materials. The present invention relates to a surface treatment method and a surface treatment apparatus for performing surface modification at high speed using a high-pressure plasma under a clean atmosphere. The “surface treatment” in the specification of the present application comprehensively includes the above-described film formation and surface modification.
[0002]
[Prior art]
As a method for forming a film in a multilayer structure of various devices such as a semiconductor device and a liquid crystal device and for forming a film of various functional materials, plasma CVD is already known and widely used in current manufacturing processes. As a method for performing surface modification in a multilayer structure of various devices such as semiconductor devices and liquid crystal devices and surface modification of various functional materials, a surface modification method using plasma is already known.
[0003]
In the plasma CVD method or the surface modification method using plasma, a reaction gas selected according to a target film formation or surface modification is made into a plasma state by a high electric field, and is treated by active species generated in the plasma. This is a method of forming a film or modifying the surface, and can be classified according to a method of generating plasma, a pressure range for generating plasma, and the like. Although there is no clear definition in the pressure range, in the method using low-pressure plasma, the density of the active species is low and the film formation rate or the surface modification rate is low because the pressure for generating the plasma is low. For this reason, the throughput of the apparatus is low, and as a result, the unit price of the product is increased.
[0004]
In order to improve the film formation rate or the surface modification rate for the purpose of solving this point, a method of increasing the plasma generation pressure to a high pressure of about atmospheric pressure and increasing the density of the active species is known, for example. It is disclosed in Japanese Unexamined Patent Publication No. Hei 2-50969, Japanese Unexamined Patent Application Publication No. 2-73978, Japanese Unexamined Patent Application Publication No. 2-73979, and the like. Hereinafter, the method disclosed in JP-A-2-73978 will be described with reference to FIG.
[0005]
FIG. 24 is a schematic diagram showing the configuration of the device disclosed in the above publication. 24, reference numeral 241 denotes a film formation chamber; 242, a non-ground substrate; 243, a ground electrode; 244, a high-resistance porous plate; 245, a sample substrate; 246, a gas inlet; 247, an RF electrode; Is a gas outlet.
[0006]
According to the above publication, electrodes 242 and 243 facing each other are provided in a film forming chamber 241, one of the non-ground electrodes 242 is connected to an RF power source 247, and the ground electrode 243 is connected to the ground. A high-resistance body (not shown) having a size equal to or larger than the electrode 243 is provided on the ground electrode 243 as necessary, and a sample substrate 245 is further provided thereon. The non-grounded electrode 242 is provided with a perforated plate high-resistance body 244, and a mixture of the film forming gas and He is supplied from the inside of the non-grounded electrode 242 to the film forming chamber 241 through the hole of the perforated plate high-resistance body 244. Supply gas. The supplied gas is simultaneously exhausted from the gas exhaust port 249 to maintain the inside of the film forming chamber 241 at a pressure close to the atmospheric pressure. At this time, assuming that the distance between the porous plate high-resistance body 244 and the sample substrate 245 is a substrate distance 240 g, the substrate distance 240 g is 0.1 mm or more and 10 mm or less.
[0007]
In such a configuration, high-frequency power is supplied from the RF power supply 247 to the non-grounded electrode 242 to generate an atmospheric pressure plasma 240p between the non-grounded electrode 242 and the grounded electrode 243, thereby forming a film on the sample substrate 245. Do.
[0008]
Table 1 shows the experimental conditions when the film forming experiment was performed using the conventional apparatus shown in FIG. 24, and Tables 2 and 3 show the experimental results. Table 2 among them is a table showing the correlation between the inter-substrate distance 240 g and the film thickness distribution. Table 3 is a table showing the correlation between the value Q / S obtained by dividing the total gas flow rate Q by the volume S of the discharge space and the film formation rate at the central portion of the substrate 245.
[0009]
[Table 1]

[0010]
[Table 2]

[0011]
[Table 3]

[0012]
As can be understood from the contents described in Tables 1 to 3, the device disclosed in the above publication is
(1) For the purpose of obtaining a stable glow discharge, a source gas for forming a film is diluted in large quantities with He;
(2) In order to form a uniform film over a large area, a high-resistance body 244 is attached to at least one of the electrodes 242 and 243 so that only an AC current flows without a DC current. Limit the current density per unit to make it easier for plasma 240p to spread evenly,
(3) From the experimental results shown in Table 2, the smaller the distance 240 g between the sample substrate 245 and the high-resistance body 244 is, the more uniform a film having a small film thickness distribution is formed. To set the distance 240 g between the sample substrate 245 and the high-resistance body 244 to 10 mm to 0.1 mm, and
(4) From the experimental results shown in Table 3, the value Q / S obtained by dividing the total gas flow rate Q by the volume S of the discharge space is 10^-1sec^-1In this case, the supplied source gas is immediately decomposed, so that the film forming rate on the substrate 245 is reduced. On the other hand, if the value Q / S is large, the supplied gas is decomposed because it immediately passes through the plasma 240p. And the gas in the discharge space is reduced to 10% because the deposition rate is reduced and the source gas is not used effectively.^-2The above Q / S is set to 1 sec so as to be replaced in 1 sec to 1 sec.^-1-10²sec^-1A mixed gas comprising a source gas for film formation and He is supplied to the discharge space so that
Has the characteristic.
[0013]
[Problems to be solved by the invention]
However, the above prior art has the following problems.
[0014]
That is, the whole of the film forming chamber 241 is filled with a mixed gas of the film forming source gas and He in a high pressure atmosphere near the atmospheric pressure to generate high-pressure plasma 240p, and the film forming source gas is decomposed to obtain a sample substrate. Since the film is formed on the plasma 245, the reaction product generated in the plasma 240p diffuses outside the plasma 240p and then floats and condenses in the atmospheric gas for a long time. As a result, an increase in the particle size of the reaction product and an increase in the number of particles of the reaction product having the increased particle size occur. When the reaction product having the increased particle diameter re-adheres to the surface of the film forming substrate 245, the particulate product is mixed into the film to lower the film quality, and also adheres to the inner wall of the reaction vessel, thereby causing the process itself to fail. Deteriorating yield.
[0015]
Further, since the inside of the film formation chamber is filled to a high pressure near the atmospheric pressure, the number of moles of gas leaking out of the film formation chamber at the time of gas leakage is large, and the safety of the apparatus is low.
[0016]
Furthermore, it takes time to exhaust the reaction gas when purging the reaction gas when the sample substrate 245 is carried out. For this reason, although the film forming speed is high, the throughput of the entire film forming apparatus is low.
[0017]
All of the above three problems are caused by filling the entire reaction vessel into a high-pressure atmosphere.
[0018]
Further, when the electrode gap 240 g is reduced, the reaction gas flow ejected from the hole of the perforated plate high resistance body 244 collides with the surface of the sample substrate 245, and the film thickness distribution immediately below the ejection hole is different from the surrounding area. Thus, the uniformity of the film on the surface of the sample substrate 245 is deteriorated.
[0019]
When the inter-electrode gap 240g is reduced, the flow distribution of the reactant gas changes due to the inclination of the non-ground electrode 242 with respect to the sample substrate 245, thereby deteriorating the film uniformity.
[0020]
Since the high-pressure plasma 240p, which is difficult to diffuse, is generated between the ungrounded electrode 242 loaded with power and the ground electrode 243 on which the sample substrate 245 is installed, the high-pressure plasma 240p is unlikely to be generated over the entire sample substrate 245, and a large area sample It is difficult to form a uniform film on the entire substrate. Further, even when the plasma 240p is generated in a region smaller than the sample substrate 245 and the ungrounded electrode 242 and the sample substrate 245 are relatively moved to form a film on the entire surface of the substrate 245, the movement of the electrode 242 or the substrate 245 is also possible. As a result, the equivalent circuit of the power supply path changes, so that a film deposition amount distribution is generated and film uniformity is deteriorated.
[0021]
In the following, among the problems of the prior art as described above, in particular, the points related to the formation and adhesion of the reaction product having a large particle diameter described in the first section, and the porous plate high resistance body 244 described in the fourth section The change in the film deposition amount distribution immediately below the nozzle hole will be further described.
[0022]
First, the principle of film quality deterioration and process yield deterioration due to filling the inside of the film forming chamber 241 near atmospheric pressure will be described.
[0023]
The supplied source gas is decomposed in the atmospheric pressure plasma 240p and reaches the deposition substrate 245, and forms a film on the deposition substrate 245. Here, in the plasma 240p, not only the decomposition and dissociation reactions of the raw material gas, but also the polymerization and condensation reactions occur simultaneously. Therefore, a large number of powdery reaction products including impurities and source gas atoms mixed in the film formation chamber 241 exist, and these reaction products also reach the surface of the substrate 245. Here, the reaction product condensed in the plasma is immediately re-decomposed by the plasma 240p, and does not reach the surface of the substrate 245. However, the reaction products released to the outside of the plasma 240p are not re-decomposed, but rather condense with each other or with impurities in the reaction vessel 242 to increase the particle size. Accordingly, the number of particles of the reaction product having such a large particle diameter also increases. The problem here is the reaction product having a large particle size, which is not immediately re-decomposed even when diffused into the plasma 240p again, reaches the sample substrate 245, and In the film formed on the substrate to significantly lower the film quality. Further, these reaction products having a large particle diameter adhere to the inner wall of the film formation chamber 241 and contaminate the inside of the film formation chamber 241, and consequently, contaminate the film surface after film formation, resulting in the process itself. Deteriorating yield.
[0024]
The problem here is that in the above-described conventional technology, the inside of the plasma 240p is in the same pressure state as the inside of the plasma 240p because the inside of the film formation chamber 241 is filled with a high pressure near the atmospheric pressure. That is. In such a case, it is conceivable to reduce the atmospheric pressure in the film forming chamber 241 to suppress the increase in the particle size and the number of reaction products outside the plasma 240p. The pressure of the plasma 240p is also reduced, lowering the film formation rate, and further deteriorating the throughput of the process.
As described above, in the above-described related art, when the film is formed near the atmospheric pressure, the film quality is degraded, or when the film is formed at a reduced pressure, high-speed film formation cannot be realized. This is because the above-described prior art itself is a method of forming a film by filling the inside of the film forming chamber 241 with a pressure near the atmospheric pressure and generating plasma 240p in principle.
[0025]
Next, a film thickness distribution generated when a film is formed immediately below the supply port of the perforated plate high resistance body 244 will be described with reference to FIG.
[0026]
FIG. 25 is a schematic diagram illustrating a film thickness distribution of the thin film 252 formed immediately below the reaction gas supply port 250. In the figure, 250 is a gas supply port, 251 is a flow of a reaction gas that collides with a sample substrate, 252 is a thin film formed on a substrate (not shown), and 253 is a thin film formed immediately below the reaction gas supply port 250 252 projections.
[0027]
24, a plasma 240p near the atmospheric pressure is generated between the ungrounded electrode 242 and the sample substrate 245, and a He gas mixture containing a source gas is supplied from many gas supply ports 250 in the plasma region. Squirt. For example, the distance between the electrodes 242 and 243 is described as 10 mm or less and 0.1 mm or more.
[0028]
However, when the distance between the electrodes 242 and 243 is small, the flow 251 of the reaction gas ejected from the gas supply port 250 collides perpendicularly with the surface of the sample substrate immediately below the gas supply port 250, and the reaction gas efficiently reacts at this location. As a result, the gas is supplied, and as a result, the film formation amount immediately below the gas supply port 250 becomes larger than that around the gas supply port 250, and a convex portion (uneven film thickness distribution) 253 as shown in FIG. 25 is formed. .
[0029]
Therefore, in the conventional technique shown in FIG. 24, the gap between the electrode 242 and the sample substrate 245 cannot be narrowed in order to suppress the occurrence of the uneven film thickness distribution 253 as described above. This is due to the configuration in which the plasma 240p is generated between the electrode 242 and the sample substrate 245, and the reaction gas supply port 250 is provided in the plasma generation part.
[0030]
In the above, the problem has been described by taking, as an example, the case where a film is formed on the sample substrate 245 by the conventional technique. However, the same problem exists when the surface is modified.
[0031]
The present invention has been made in order to solve the above-mentioned problems, and its object is to (1) perform film formation or surface modification on a sample surface with high efficiency, and generate a reaction on a sample surface in a clean atmosphere. To provide a surface treatment method and a surface treatment apparatus using plasma capable of forming a good-quality film or modifying the surface without reattaching a substance, and (2) generating a plasma with a desired gas atmosphere pressure at least. By keeping the pressure lower than that of the section or maintaining a vacuum, the reaction product is not condensed and the film thickness or the uneven thickness distribution of the treated layer just below the reaction gas ejection area does not occur. An object of the present invention is to provide a surface treatment method and a surface treatment apparatus using plasma, which can perform uniform film formation or surface modification.
[0032]
[Means for Solving the Problems]
The sample surface treatment apparatus using the plasma according to the present invention is provided in a predetermined gas atmosphere.A sample table on which a sample to be surface-treated is placed, and a wall surface having at least a portion similar to the shape of the surface to be processed of the sample are provided so as to face the surface to be processed of the sample. An electrode, a reaction gas supply port provided on a wall surface of the electrode so as to locally supply a reaction gas to a surface to be processed of the sample, a power supply for applying power to the electrode, and the reaction on the wall surface. A power transmission line provided in the electrode so as to transmit power applied to the electrode to the open end, the power transmission line being provided at a position distant from the gas supply port; A gas channel having a low conductance is formed between the reaction gas supply port and the gas atmosphere between the sample and the surface to be processed of the sample. The pressure of the gaseous atmosphere and the reaction gas supplied from the reaction gas supply port A high-pressure reaction gas region having a pressure higher than the gaseous atmosphere due to a pressure difference from the pressure is locally formed near the open end in the low conductance gas flow path, and the power transmitted to the open end Generate a high electric field,Local high-pressure plasma based on the reaction gasBy generating in the high-pressure reaction gas region,Surface treatment of the sample by a reactive species of a reactive gas in the high-pressure plasmaIs doneThereby, the above object is achieved.
Further, in the sample surface treatment apparatus using plasma according to the present invention, the wall surface having at least a part of a shape similar to the shape of the surface to be processed of the sample placed in a predetermined gas atmosphere is formed on the surface to be processed of the sample. An electrode provided oppositely, a reaction gas supply port provided on a wall surface of the electrode so as to locally supply a reaction gas to a surface to be processed of the sample, and a power supply for applying power to the electrode. At least one of the sample and the electrode has a small gap between the surface to be processed of the sample and the wall surface due to a differential pressure between the pressure of the gas atmosphere and the pressure of the reaction gas supplied from the reaction gas supply port. Are formed so as to float with a gap therebetween, and the minute gap forms a gas channel of low conductance from the reaction gas supply port toward the gas atmosphere, and the gas atmosphere is formed by the differential pressure. Higher pressure A high-pressure reaction gas region having a pressure is formed locally at a position distant from the reaction gas supply port in the low conductance gas flow path, and by applying power to the electrode, the reaction gas is applied to the high-pressure reaction gas region. Generating a local high-pressure plasma based on the sample, a surface treatment is performed on the sample by a reactive species of a reactive gas in the high-pressure plasma,SoThus, the above object is achieved.
Preferably, the sample is placed on a sample stage.
Preferably, there is further provided a means for setting a ratio of a pressure p0 of the gas atmosphere to a pressure px of the high-pressure plasma generation location in the high-pressure reaction gas region so that px / p0> 1.
Preferably, a wall surface of the electrode is arranged to face a surface to be processed of the sample with a minute gap therebetween.
Preferably, at least one of the electrode and the sample stage is movable so as to float with a small gap from the other of the electrode and the sample stage by the differential pressure.
Preferably, at least one of the electrode and the sample stage is provided with a magnetic force generating mechanism that generates a magnetic force of a predetermined magnitude, and controls both the magnetic force generated from the magnetic force generating mechanism and the differential pressure. Utilizing this, one of the electrode and the sample stage is floated with a small gap from the other.
Preferably, inside the electrode, a power transmission line having an open end at a position away from the reaction gas supply port on the wall surface of the electrode is provided, and the power transmission line is applied to the electrode. Power is transmitted to the open end, and the transmitted power generates a high electric field near the open end.
Preferably, the power transmission line includes an inner conductor to which power is applied, and an electric field shielding conductor which covers the inner conductor via an insulator and is grounded.
Preferably, the power applied to the electrodes is high-frequency power in a frequency band of 10 MHz to 1 GHz or microwave power in a frequency band of 1 GHz or more.
Preferably, the power transmission line is constituted by a waveguide.
Preferably, at least one of the electrode and the sample stage is provided with a power absorber having a large absorption coefficient with respect to an electromagnetic wave having a frequency of a power supply to be used, and the power absorber is provided with the low-conductance gas flow. The path is arranged on a lower pressure side than the high-pressure plasma generation area, absorbs electromagnetic waves passing through the high-pressure plasma generation area, and prevents generation of plasma in the gas atmosphere in a surrounding area of the high-pressure plasma. Suppress.
[0054]
BEST MODE FOR CARRYING OUT THE INVENTION
Prior to the description of a specific embodiment of the present invention, first, a high-pressure reaction gas for performing film formation or surface treatment is locally supplied near a sample placed in a gas atmosphere in the present invention, A method of forming a gas flow field such that a high-pressure reaction gas region is formed nearer to the sample than a gas atmosphere will be described with reference to FIGS.
[0055]
FIG. 22 is a schematic diagram showing the formation of a gas flow field by the disk H0.
[0056]
Specifically, when the film formation surface shape of the film formation sample J is a plane, the disk H0 having a plane shape with an outer radius R2, an inner radius R1, and a thickness T1 is separated by a gap t0 to form a film. A high-pressure gas having a pressure of ps is locally supplied to the sample J through a high-pressure gas supply path 101 through an inner diameter hole having a radius R1. Further, this high-pressure gas flows through a gas flow path formed between the disk H0 and the sample J on which the film is to be formed into a gas atmosphere around the disk H0 at the pressure p0.
[0057]
Here, the weight flow rate w and the pressure distribution p of the gas flowing between the disk H0 and the sample J are obtained with reference to FIG. FIG. 23 is a diagram in which a cylindrical coordinate axis is set between the disk H0 and the sample J to be formed.
[0058]
As shown in FIG. 23, a straight line perpendicular to the film formation plane and the disk H0 and passing through the center of the disk H0 is defined as the z-axis, and a point where the z-axis intersects the film formation plane is defined as an origin O. Further, as shown in FIG. 23, it is assumed that a straight line passing through the origin O and on the plane on which the film is to be formed is defined as the r-axis of the cylindrical coordinate system, and the rotation angle θ0 is set counterclockwise therefrom.
[0059]
First, the weight flow rate w of the gas flowing between the disk H0 and the sample J is determined. The flow rate w of the gas can be obtained by using a flow rate defined by a Navier-Stokes equation, which is an equation of motion of a gas in consideration of viscosity. When this Navier-Stokes equation is expressed in a cylindrical coordinate system, the following equation (1) is obtained.
[0060]
(Equation 1)

[0061]
Here, in order to determine the gas flow rate w flowing between the disk H0 and the sample J, the following assumptions are made:
(1) The distance t0 between the disk H0 and the sample J to be film-formed is much smaller than the outer radius R2 of the disk.
(2) The flow between the disk H0 and the sample J is a developed boundary layer flow.
(3) There is no pressure distribution in the z-axis direction, and therefore ignores the gas velocity in the z-axis direction.
(4) There is no pressure distribution in the θ direction, so the velocity of gas in the θ axis direction is ignored.
(5) Inertia force term is smaller than pressure gradient term
(6) The main viscous force is δ²v_r/ Δz²Only and ignore others.
When the above assumption is applied to equation (1), it is simplified as in equation (2) below.
[0062]
(Equation 2)

[0063]
Where p is the pressure distribution in the r direction, v_rIs the flow velocity distribution in the r direction, and μ is the viscosity coefficient of the gas.
[0064]
On a wall, the velocity of the gas can be equal to the velocity of the wall, so the boundary condition is
[0065]
(Equation 3)

[0066]
It becomes. Since the pressure p does not have a distribution in the z direction, solving equation (2) for the boundary condition of equation (3) gives
[0067]
(Equation 4)

[0068]
Is obtained. Accordingly, the weight flow rate w of the gas flowing between the disk H0 and the sample J to be deposited is:
[0069]
(Equation 5)

[0070]
It is expressed as Where ρ is the density of the gas.
[0071]
On the other hand, the following equation (6) obtained from the equation of state of gas,
[0072]
(Equation 6)

[0073]
(Where m is the molecular weight m of the gas, R0 is the gas constant, and T0 is the absolute temperature).
[0074]
(Equation 7)

[0075]
Is obtained. Here, since w must take a constant value regardless of r,
[0076]
(Equation 8)

[0077]
Is obtained. Than this,
[0078]
(Equation 9)

[0079]
(Where E0 and F0 are integration constants, respectively). Substituting the boundary conditions into this gives
[0080]
(Equation 10)

[0081]
(Equation 11)

[0082]
Is obtained. Therefore, the force acting on the lower surface of the disc H0 by the gas pressure between the disc H0 and the sample J to be deposited is obtained by integrating the above equation (10),
[0083]
(Equation 12)

[0084]
Can be obtained from At the same time, the pressure p0 of the surrounding atmosphere acts on the upper surface of the disk H0.
[0085]
(Equation 13)

[0086]
A force f acts in the positive direction of the z-axis.
[0087]
Also, from equation (11),
[0088]
[Equation 14]

[0089]
(Equation 15)

[0090]
(Equation 16)

[0091]
Is obtained. At this time, since w in the equation (16) is a flow rate and ps-p0 is a differential pressure, C0 represents a conductance, and the following equation (17):
[0092]
[Equation 17]

[0093]
Is represented by
[0094]
Here, the conductance C0 of the gas flow path composed of the disk H0 and the sample J to be film-formed changes depending on the pressures ps and p0, but when this conductance C0 is set by a geometric boundary condition, t0 , R2, R1.
[0095]
In the above, the method of setting the pressure of the gas for generating plasma to a high pressure, for example, near the atmospheric pressure, and supplying a large number of gas molecules into the plasma to achieve a high film forming rate is a method described as a conventional technique. It is.
[0096]
Here, the gas is supplied at the pressure ps1, the required predetermined gas flow rate is w1, the ambient pressure of the disk H0 at that time is p01, the physical properties of the gas at that time, and the boundary conditions R1, R2, and t0 of the disk. Is determined as c = c1, and the conductance is C0 = C01.
[0097]
Here, the type (molecular weight m), pressure (ps), and temperature (T) of the gas supplied to generate plasma are determined by the sample J to be formed, the target film specification, the plasma phenomenon, and the like. Therefore, it cannot be changed. The parameters that can be changed are the atmospheric pressure p0 around the disk and the arrangement of the disk H0, that is, the boundary conditions R1, R2, and t0.
[0098]
First, consider the case where R1, R2, and t0 are set such that c = c1 becomes very large. This is because the conductance C0 of the gas flow path from the high-pressure reaction gas supply section to the surrounding gas atmosphere is increased by increasing the width t0 of the gas flow path from the supply section to the periphery of the disk and increasing R2 / R1. (C0 = C01).
[0099]
At this time, from Expressions (14) and (15), ps1 ≒ p01, and the high-pressure gas supply unit pressure ps and the disk peripheral pressure p0 become equal. From equation (10), p ≒ ps ≒ p0 (R1 ≦ R ≦ R2), and the pressure between the disc H0 and the sample J on which a film is to be formed is a gas flow path from the high pressure supply unit to the surrounding gas atmosphere. No distribution occurs.
[0100]
On the other hand, while maintaining the required gas supply amount w1 and the supply gas pressure ps1 at the same value, the conductance C0 is reduced to C0 = C02 (C01> C02), and the surrounding gas pressure p0 is correspondingly reduced. Consider the case of setting (p0 = p02 <ps1 ≒ p01).
[0101]
At this time, from the equations (14) and (15), the gas flow rate w is expressed as w = w1 = c2 (ps1²-P02²) Is maintained, and ps1 (supply unit pressure)> p02 (atmospheric pressure around the disk H0), the pressure distribution represented by the equation (10) is changed to the disk H0− It is formed between the workpieces J, that is, in the low conductance flow path portion. Thus, the pressure between the disc H0 and the sample J is all higher than the pressure p0 = p02 around the disc.
[0102]
Considering the above points, as a method of supplying gas at the same pressure ps1 and achieving a certain supply amount w1 of gas,
(1) The gas flow field (this time, the wall surface H0) is set so that the conductance of the gas flow path from the supply unit to the surrounding atmosphere is increased, and the gas is supplied in a state where the supply pressure ps is equal to the ambient pressure p0. Shed or
(2) The above-mentioned wall surface H0 is set so that the conductance becomes low, and the gas is caused to flow in a state where the differential pressure between the supply pressure ps and the ambient pressure p0 is large.
There are two cases.
[0103]
Here, further consider a case in which plasma is generated between the disk H0 and the sample J to be film-formed, and ps is increased to supply a high-pressure gas in order to achieve a high film-forming speed.
[0104]
As described above, in both cases (1) and (2), the same gas flow rate w = w1 flows between the disk H0 and the sample J to be deposited. The film forming speed in each case is the same.
[0105]
However, in the case of the above (1), there is no pressure distribution between the pressure ps of the supply unit and the surrounding pressure p0 between the disk H0 for generating plasma and the sample J for film formation, and the pressures are all the same. Here, since the plasma portion is at a high pressure, the mean free path of the particles is short, and therefore, the particles easily collide and condense to form a reaction product. These reaction products are immediately redissolved in the plasma and do not contaminate the surface on which the film is to be formed. However, in the ambient gas atmosphere, the ambient atmospheric pressure is as high as that of the plasma part, so due to the short mean free path, collision and condensation are repeated very frequently, and the reaction product having a large particle size Is formed. A reaction product having a large particle size is not immediately decomposed due to its large particle size even when diffused into plasma, but adheres to a surface on which a film is to be formed and is taken into the film, thereby deteriorating the film quality. Further, even after film formation, it adheres to the film surface, and tends to contaminate the workpiece surface instead of achieving a high film formation rate. As described above, the reaction product generated in the plasma is immediately re-decomposed and the powdery reaction product does not grow. It is caused by growing by pressure.
[0106]
When the ambient gas atmosphere pressure p0 = p01 is reduced in order to suppress the generation of reaction products, the pressure ps of the supply unit and the ambient pressure p0 between the disk H0 for generating plasma and the sample J for film formation are further equal. Therefore, the pressure of the plasma part also decreases. As a result, good film quality and a clean surface can be obtained, but a high film forming rate cannot be achieved.
[0107]
As a result, in the state (1), a high film forming rate and a clean surface cannot be simultaneously realized.
[0108]
On the other hand, in the above case (2), the same gas supply amount w1 for achieving a high film formation rate is realized, and at the same time, the conductance C0 of the gas flow path is reduced to the pressure ps of the supply unit. On the other hand, the ambient atmosphere pressure p02 satisfying ps> p02 is maintained. In such a state, the reaction product generated in the plasma is immediately re-decomposed as in (1), and does not contaminate the surface on which the film is to be formed. In the case of (2), the ambient gas atmosphere has a relatively long mean free path since the pressure is lower than that between the disk H0 for generating plasma and the sample J for film formation. Therefore, collision and condensation of the reaction product are unlikely to occur, and a clean film can be formed without growing the reaction product having a large particle diameter.
[0109]
As described above, in the case of the above (2), a high film forming rate is achieved by setting the plasma portion to a high pressure, and at the same time, since the surrounding atmosphere is at a lower pressure than the plasma portion, the film quality is improved. In addition, a clean deposition surface can be obtained.
[0110]
The smaller the ambient pressure p0, the more clean a film can be formed. This minimum value is when p0 = 0, that is, when the surroundings are in a vacuum state.
[0111]
Table 4 below shows the states of the supply pressure ps, the surrounding atmosphere p0, the weight flow rate w, the conductance C0, and the constant c in each of the above cases (1) and (2).
[0112]
[Table 4]

[0113]
According to the present invention, the film formation is performed in such a manner that the gas flow path from the high-pressure gas supply unit to the atmosphere around the disk H0 is opposed to the disk H0 having the inner radius R1 and the outer radius R2 at a distance t0 from the disk H0. Formed by sample J. The conductance of this gas flow path was also determined using the Navier-Stokes equation (Equation 1), which is the equation of motion of a viscous gas.
[0114]
However, the differential pressure between the high-pressure gas supply unit and the surrounding atmosphere can be formed by setting the flow field of the gas from the high-pressure gas supply unit to the surrounding atmosphere and further reducing the conductance of the flow field. A specific method at this time is not limited to a method in which the interval t0 between the disk H0 and the workpiece J is reduced and R2 / R1 is increased. In addition, the conductance C0 in the case where the pressure of the flowing gas is low must be actually obtained not by the above-mentioned Navier-Stokes equation but by the gas molecule kinetics. However, regardless of how to obtain the conductance C0, by setting the gas flow path from the high-pressure gas supply unit to the surrounding atmosphere to a low conductance, a high deposition rate as shown in the case of (2) above can be obtained. The formation of a clean surface is realized.
[0115]
Hereinafter, a method and apparatus for surface treatment (film formation or surface modification) using plasma of the present invention achieved based on the above considerations will be described with reference to the accompanying drawings.
[0116]
(1st Embodiment)
FIG. 1 shows an electrode floating type high-voltage floating electrode H1, a sample J, a sample stage T, a scanning stage S, a reaction vessel C, a power source G, a resonance / matching device M, a flexible power transmission line I, a power transmission line K, a high pressure reaction. FIG. 2 is an overall conceptual diagram showing an arrangement relationship among a gas supply device R, an exhaust device E, an electrode scanning device U, and a control device N for controlling them. Although not shown, a sample-electrode gap measuring device for measuring the sample-electrode gap is provided, and the electrode H1 and the sample table T are further provided with a water-cooling mechanism or a heating mechanism (not provided) for adjusting the respective temperatures. (Shown). The sample table T further includes a sample fixing section F.
[0117]
FIG. 2 is a cross-sectional view of the electrode floating type high-voltage floating electrode H1 described above.
[0118]
In FIG. 2, reference numeral 1 denotes a high-pressure reaction gas supply path for transporting the high-pressure reaction gas from the high-pressure reaction gas supply device R to the electrode floating type high-pressure floating electrode H1. Reference numeral 2 denotes a high-pressure reactant gas supply port provided at a position facing the sample J of the electrode levitation type high-pressure levitation electrode H1 and ejecting the high-pressure reactant gas transported from the high-pressure reactant gas supply device R. Reference numeral 111 denotes a buffer unit that prevents the pressure of the reaction gas supplied from the high-pressure reaction gas supply port 2 from being distributed by the supply port 2, and the plurality of buffer units 111 depicted in the drawing actually Are connected to each other. Reference numeral 3 denotes a reaction product exhaust path connecting the reaction gas exhaust port 4 and the exhaust device E. The reaction gas exhaust port 4 is connected to an exhaust device E, and exhausts a reaction product generated by a reaction in the local high-pressure plasma P (also referred to as “local high-pressure plasma P”). Reference numerals 5 and 6 are an inner electrode and an outer electrode of the electrode floating type high-voltage floating electrode H1, respectively. Reference numeral 11 denotes an insulator that insulates between the inner electrode 5 and the outer electrode 6, and reference numeral 7 denotes an open end of the power transmission line formed by the inner electrode 5, the outer electrode 6, and the insulator 11. Reference numeral 8 denotes a connector for connecting the electrode floating type high-voltage floating electrode H1 and the flexible power transmission line I. Reference numeral 9 denotes a scanning wire or a belt for connecting the electrode levitation type high voltage levitation electrode H1 and the drive motor 10, and by rotating the drive motor 10 therethrough, the electrode levitation type high voltage levitation electrode H1 is moved relative to the sample J. Move. The scanning wire (belt) 9 and the drive motor 10 are collectively referred to as a scanning device U.
[0119]
FIG. 3 is a lower oblique view showing a portion of the electrode floating type high-voltage floating electrode H1 facing the sample.
[0120]
As shown in the figure, the electrode shape of the electrode floating type high-pressure floating electrode H1 is a disk shape having the reaction product exhaust port 4 at the center. The high-pressure reactant gas supply port 2 is a small hole shown in FIG. 3, and a plurality of such small holes are arranged on the same circumference. These micropores are preferably arranged such that the pressure distribution (flow rate distribution) of the gas supplied therefrom is uniform, and specifically, it is preferable to arrange them at regular intervals on a certain circumference. . Further, the open end 7 of the power transmission line for generating the local high-pressure plasma P has the same circumferential shape, and its formation position is sufficiently away from the high-pressure reaction gas supply port 2 to the side closer to the reaction gas discharge port 4. Provide.
[0121]
FIG. 4 is a partial sectional view showing a step t between the sample J and the sample table T.
[0122]
In the first embodiment of the present invention, a sample J and an electrode-floating high-pressure floating electrode H1 are arranged in a reaction vessel C so as to face each other, and a high-pressure reaction gas supply device R is used based on target film characteristics and the like. The high-pressure reaction gas determined in this way is supplied to the electrode floating type high-pressure floating electrode H1 through the high-pressure reaction gas supply path 1. The high-pressure floating electrode H1 floats at a minute interval D with respect to the sample J by supplying a high-pressure reaction gas from the high-pressure reaction gas supply port 2 to a portion where the high-pressure floating electrode H1 and the sample J face each other. In the above configuration, since the distance D between the electrode H1 and the sample J is very small, the gas supplied to this portion is unlikely to flow out into the atmosphere around the electrode. Therefore, a portion sandwiched between the electrode H1 and the sample J is maintained at a high pressure, and a high-pressure portion is formed here.
[0123]
Accordingly, as described in connection with the theory of generating a differential pressure in the gas flow path having a low conductance (the case of using the differential pressure between the supply pressure ps and the ambient pressure p0 as in (2) described above), A portion of the high-pressure floating electrode H1 facing the sample J is a wall surface that makes a gas flow path from the high-pressure reaction gas supply port 2 to the gas atmosphere in the reaction vessel C a low-conductance gas flow path. The reaction gas region (high-pressure reaction gas region) having a higher pressure than the gas pressure in the reaction vessel C exhausted by the apparatus E is locally added to the low conductance portion due to the minute interval D between the high-pressure floating electrode H1 and the sample J. Form.
[0124]
Further, the power generated from the power source G is transmitted to the high-voltage floating electrode H1 through the power transmission line K, the resonance / matching device M, and the flexible power transmission line I, and further includes the inner electrode 5, the outer electrode 6, and the insulator 11. Through the in-electrode power transmission line, the power is transmitted to the power transmission line open end 7 provided at a portion of the high-pressure floating electrode H1 facing the sample J and at a position away from the high-pressure reaction gas supply port 2. The generated high electric field is located at the position of the open end 7 of the power transmission line, that is, in the high pressure reaction gas region in the minute interval D between the high pressure floating electrode H1 and the sample J, and A local high-pressure plasma P is generated in a portion away from the supply port 2. The high-pressure reaction gas is decomposed and activated in the local high-pressure plasma P, and a film is formed on the sample J immediately below the plasma P.
[0125]
The reaction product generated in the plasma P is immediately exhausted by the exhaust device E from the reaction product exhaust port 4 through the reaction product exhaust path 3. Further, the reaction products flowing into the gas atmosphere in the reaction vessel C are removed by immediately exhausting the entire reaction vessel C by the exhaust device E in the same manner.
[0126]
Further, in the above configuration, the film is formed over the entire surface of the sample J by changing the relative position between the high-pressure floating electrode H1 and the sample J using the scanning device U and the scanning stage S. it can. Further, control for performing desired film formation is performed by the control device N.
[0127]
As described above, in the above configuration, since the local high-pressure plasma P is generated in the high-pressure atmosphere in the minute interval D between the high-pressure floating electrode H1 and the sample J, a high-density active species can be generated. A high deposition rate can be realized. At the same time, the pressure in the reaction vessel C (the pressure of the surrounding gas atmosphere) is lower than that in the high pressure atmosphere between the high pressure floating electrode H1 and the sample J where the local high pressure plasma P is generated and the film is formed. As described above, a reaction product having a large particle size does not grow, a high-quality film can be formed on the sample J, and the film surface is also cleaned. Can be maintained.
[0128]
As the pressure in the reaction vessel C is lower, a clean film surface is obtained, and a high-quality film can be formed. In particular, the maximum effect can be obtained when the atmosphere in the reaction vessel C is vacuum.
[0129]
Further, when the pressure in the reaction vessel C is 1 atm or less, the pressure is lower than the atmosphere outside the reaction vessel C, so that even when gas leaks, the gas atmosphere in the reaction vessel C Without leaking outside, the safety of the device can be enhanced.
[0130]
Further, when the atmosphere in the reaction vessel C is a vacuum atmosphere, the time for exhausting the reaction gas during the purge of the reaction gas when the sample J is carried out of the reaction vessel C may be extremely short or completely eliminated. As a result, the throughput of the apparatus is improved.
[0131]
Further, as described above, the electrode H1 is floated with respect to the sample J by the differential pressure between the high pressure at the minute interval D and the atmosphere (ambient gas atmosphere) in the reaction vessel C. The small interval D can be maintained without tilting. During the minute interval D, a steady flow of the reaction gas from the high-pressure reaction gas supply port 2 to the atmosphere in the reaction vessel C or the reaction product exhaust port 4 is formed along the sample surface. By generating the local high-pressure plasma P in the minute interval D where such a flow is formed, a film having a uniform film thickness distribution can be formed.
[0132]
In addition, the local high-pressure plasma P is generated not in the area immediately below the high-pressure reaction gas supply port 2 but in a portion away from the supply port 2, so that the reaction gas jet flow of the supply port 2 reduces the film formation amount around the supply port 2. A film formation amount distribution in which the film formation amount immediately below the supply port 2 is increased is not formed. As a result, a film having a uniform thickness distribution can be formed.
[0133]
In addition,
(1) A method of floating the electrode H1 with respect to the sample J by a minute interval D and its effect,
(2) A method of generating plasma P by the power transmission line open end 7 and its effect,
(3) A method of obtaining a good film quality and a clean film formation surface, and
(4) A method for preventing the formation of a film thickness distribution immediately below the gas supply port 2
Will be described in detail.
[0134]
First, as (1), a method of floating the electrode H1 with respect to the sample J by a small interval D will be described.
[0135]
FIG. 5A is a schematic cross-sectional view showing the vicinity of the minute interval D between the electrode floating type high-pressure floating electrode H1 and the sample J, and FIG. FIG. 4 is a schematic diagram showing a pressure distribution of FIG. In FIG. 5B, P0 is the pressure at the high pressure reaction gas supply port, P1 is the gas pressure in the reaction vessel, and P2 is the pressure at the reaction gas exhaust port.
[0136]
This pressure distribution can be defined algebraically in a simple case as shown in FIG. 22, and at the same time, the force received from the gas pressure can be calculated by the above equation (13). However, when a large number of high-pressure reactant gas supply ports 2 are provided like the electrode H1, it cannot be obtained algebraically, and a numerical analysis is performed using a method such as a finite element method. Similarly, the force that the electrode H1 simultaneously receives from the gas pressure is obtained by numerical analysis.
[0137]
The high-pressure reaction gas supplied from the high-pressure reaction gas supply device R while controlling the reaction gas type, temperature, pressure, flow rate, and mixing ratio is passed through the high-pressure reaction gas supply path 1 to the inside of the electrode floating type high-pressure floating electrode H1. Is supplied. The high-pressure reaction gas supplied to the inside of the electrode levitation high pressure levitation electrode H1 is supplied to the high pressure reaction gas supply provided at a position facing the sample J in the electrode levitation high pressure levitation electrode H1 shown in the sectional view of FIG. The liquid is supplied from the port 2 to the space between the high-pressure floating electrode H1 and the sample J. Then, by receiving a force due to a pressure difference between the gas atmosphere in the reaction vessel C which has been evacuated to a low pressure or vacuum by the exhaust device E, the electrode floating type high pressure floating electrode H1 is floated by a minute interval D from the sample J.
[0138]
Since the floating amount of the minute interval D is small, the conductance of the gas flow path from the high pressure reaction gas supply port 2 to the low pressure or vacuum atmosphere of the reaction vessel C becomes very small, and the reaction gas supply port 2 in FIG. A pressure distribution that changes continuously from the reaction gas supply pressure P0 to the low pressure of the reaction vessel C or the pressure P1 of the vacuum atmosphere is formed. At the same time, a reaction gas exhaust port that opens to the sample facing portion 12 of the electrode levitation type high pressure levitation electrode H1 and is connected to the exhaust device E through the reaction product exhaust path 3 to exhaust the reaction gas and the reaction product in the minute interval D. 4, a low-pressure atmosphere with a pressure P2 (P2 <P0) is formed. Thus, similarly, a pressure distribution is formed that changes from the pressure P0 at the high-pressure reaction gas supply port 2 to the low pressure P2 in the area around the reaction gas exhaust port 4. The electrode H1 floats due to the balance between the pressure difference between the atmosphere in the reaction vessel C and the weight of the electrode H1 due to the pressure distribution changed by the minute interval D.
[0139]
The minute interval D is a reaction gas supply pressure P0, a reaction vessel pressure P1, an electrode weight, an electrode-sample facing area, an outlet shape of the high pressure reaction gas supply port 2, and an exhaust speed at a reaction product exhaust port in the high pressure floating electrode. Is determined by The electrode-sample gap is measured by a sample electrode gap measuring device (not shown), and the reaction gas supply pressure P0, the temperature, the mixing ratio, the ambient pressure, the temperature, and the like are controlled, so that a wide facing area between the electrode H1 and the sample J is obtained. In contrast, the electrode-sample interval can be stably controlled to a minute interval of 1 μm to several hundred μm.
[0140]
At this time, it is also possible in principle to measure the electrode-sample distance by the inter-electrode gap measuring device and to keep the electrode-sample distance constant by the stage S. However, in practice, it is difficult to perform a precise gap measurement due to deformation of the electrode H1 and the sample J due to the heat of the plasma, an electric field for generating the plasma, and a corrosive atmosphere. Even in such a case, according to the present invention, the electrode H1 is floated with respect to the sample J by using the pressure difference between the electrode and the sample and the pressure difference between the atmosphere in the reaction vessel C and the electrode H1. For a large opposing area of J, the electrode-sample interval can be stably controlled to a minute interval of 1 μm to several hundred μm.
[0141]
Further, although not shown, a magnetic substance or a magnetic force generating mechanism is provided on the electrode H1 and the sample stage as necessary, and the electrode H1 is floated by the magnetic force generated from the magnetic substance or the magnetic force generating mechanism. The pressure P0 of the unit can be set low, and the pressure condition of the high-pressure reactant gas supply port can also be set according to the target film characteristics instead of the weight of the electrode H1.
[0142]
Next, as (2), a method of generating the local high-pressure plasma P in the high-pressure reaction gas region in the minute interval D will be described.
[0143]
FIG. 6 is a schematic diagram showing generation of local high-pressure plasma P at the power transmission line open end 7 provided at a portion of the electrode floating type high-voltage floating electrode H1 facing the sample J.
[0144]
The power generated from the power supply G of FIG. 1 passes through the power transmission line K and reaches the resonance / matching device M. The power subjected to boosting and impedance matching as needed by the resonance / matching device M is efficiently transmitted to the high-voltage floating electrode H1. The power boosted by the resonance / matching device M is supplied to the electrode floating type high-voltage floating electrode H1 through the flexible power transmission line I, and further, the power within the electrode constituted by the inner electrode 5, the outer electrode 6, and the insulator 11 Through the transmission line, it reaches a power transmission line open end 7 provided at a portion of the high-pressure floating electrode H1 facing the sample J and at a position away from the high-pressure reaction gas supply port 2.
[0145]
In the embodiment shown in FIG. 2, the power transmission line open end 7 is configured such that the power transmission line K for transmitting a DC or AC voltage from the power source G, the flexible power transmission line I, and the in-electrode power transmission line eventually become In the sample facing portion 12 of the high-voltage floating electrode H1, it means a portion where the inner electrode 5 and the outer electrode 6 are terminated while being insulated by the insulator 11. The installation of the open end 7 of the power transmission line generates a high voltage or a strong electric field between the inner electrode 5 and the outer electrode 6 as shown in FIG. The plasma P can be generated between the outer electrode 5 and the outer electrode 6. Further, the expansion of the plasma P other than between the outer electrode 6 and the inner electrode 5 can be suppressed, and the local high-pressure plasma P can be generated.
[0146]
Since the power transmission line open end 7 is formed in the sample facing portion 12 of the high-pressure floating electrode H1, the local high-pressure plasma P is generated in the high-pressure reaction gas region between the high-pressure floating electrode H1 and the sample J. The high-pressure reaction gas is dissociated in the local high-pressure plasma P, generates active species based on the reaction gas, and forms a film on the surface of the sample J. The active species become very dense based on the high-pressure reaction gas, and it is possible to form a film at a high speed.
[0147]
In the case of the present embodiment, the plasma P can be generated between the inner electrode 5 and the outer electrode 6 regardless of the presence or absence of the sample J by using the inner electrode 5 as a cathode electrode and the outer electrode 6 as an anode electrode. Therefore, the equivalent circuit of the power transmission line K does not change during the electrode scanning, the plasma P is stabilized, and a uniform film thickness distribution can be obtained. The stability of the plasma P is not limited to the case where the inner electrode 5 is the cathode electrode and the outer electrode 6 is the anode electrode. A high electric field is generated at the open end of the power transmission line, and the plasma P is generated regardless of the presence or absence of the sample J. Caused by the occurrence.
[0148]
Further, although not shown here, a power absorber having a large absorption coefficient for the electromagnetic wave of the frequency of the power supply G to be used is provided on at least one of the electrode H1 and the sample stage T from the reaction gas supply unit 2 to the surroundings. If provided on the low pressure side of the region where the local high-pressure plasma P is generated in the low conductance flow path flowing into the gaseous atmosphere, it is possible to absorb the electromagnetic waves that are not consumed by the local high-pressure plasma P and pass through. This can prevent generation of plasma in the surrounding gas atmosphere, particularly when the pressure inside the reaction vessel is a vacuum atmosphere. Further, if the power absorber as described above is provided, the equivalent circuit of the power transmission line K does not change during the electrode scanning, the plasma is stabilized, and a more uniform film thickness distribution can be obtained.
[0149]
Next, as (3), a method of forming a film of the sample J at a high speed and obtaining a clean film-forming surface having good film quality according to the present embodiment will be described below.
[0150]
In the present invention, high-density active species based on the high-pressure reaction gas are generated by the local high-pressure plasma in the high-pressure reaction gas region to achieve a high film formation rate for the sample J, and at the same time, the pressure in the reaction vessel is reduced by the local high-pressure plasma. By maintaining the pressure lower than the pressure of the generating unit or maintaining the vacuum, a good film quality and a clean film forming surface are obtained. The gas type, temperature, and pressure used for the reaction gas must be selected according to the target film material. Further, the gas used as the reactive gas species is not limited to one type, and the optimal conditions are set by mixing with a rare gas or another reactive gas.
[0151]
The high-pressure reaction gas supplied from the high-pressure reaction gas supply port 2 is supplied from the high pressure P0 of the high-pressure reaction gas supply port 2 as shown in FIG. It moves to the pressure P2 of the gas exhaust port 4 according to a continuously changing pressure distribution. Then, the local high-pressure plasma P generated at the power transmission line open end 7 provided in the sample facing portion 12 of the high-pressure floating electrode H1 is decomposed and excited to generate active species based on the reaction gas, and the local high-pressure plasma P The film is formed immediately below.
[0152]
Here, what occurs in the reaction by the local high-pressure plasma P is not only the active species that contribute to the film formation, but also molecules and atoms that do not contribute to the film formation, and carbonized powders that are mutually or in the reaction vessel. A reaction product that adheres and polymerizes with a metal powder or the like is also generated. The carbonized powder and the metal powder are generated from various structural materials such as a supply gas, an electrode material, and a reaction vessel material. These are called impurities. The reaction products as described above also reach the surface of the sample J, but when the film formation proceeds while these reaction products adhere to the surface of the sample J, the reaction products are taken into the film and the quality of the film is reduced. Deteriorate.
[0153]
In plasma, the condensed reaction product is immediately re-decomposed by the plasma when the particle size is small, and does not reach the substrate surface as a reaction product. However, the reaction products discharged to the outside of the plasma condense with each other or easily with impurities in the reaction vessel without being re-decomposed. As a result, the particle size of the reaction product increases, and the number of particles of the reaction product having a large particle size increases. The problem here is the reaction product having a large particle size, which is produced as described above. The reaction product having a large particle diameter is not immediately re-decomposed even when it is diffused into the plasma again, and reaches the sample substrate J with a certain particle diameter and forms on the substrate J. Incorporation into the deposited film significantly reduces the quality of the film. Alternatively, the reaction product having a large particle size adheres to the inner wall of the reaction vessel C and contaminates the inside of the reaction vessel C. As a result, the film surface after film formation is contaminated and the yield of the process itself is deteriorated. Let it.
[0154]
The problem above is that the outside of the plasma is in the same pressure state as the plasma part. For this reason, the reaction products released to the outside of the plasma float in the film formation chamber for a long time, and during that time, impurities and the impurities in the reaction vessel may be generated many times due to the short mean free path caused by the high pressure atmosphere. Repeated collision and condensation cause an increase in the particle size of the reaction product and an increase in the number of particles of the reaction product having a large particle size. Also, as described above, even when it diffuses again into the plasma, it reaches the surface of the sample J without being immediately re-decomposed, and significantly deteriorates the film quality by being mixed into the film.
[0155]
On the other hand, in the present embodiment, the high pressure floating electrode H1 is opposed to the sample J, and the gas flow path from the high pressure reaction gas supply port 2 to the internal atmosphere of the reaction vessel C is a low conductance gas flow path. As a result, a reaction gas region having a pressure higher than the atmospheric pressure in the reaction vessel C is formed in the gas flow path portion between the sample J and the electrode H1, and the plasma P is generated therein, thereby achieving a high film formation rate. On the other hand, since the atmospheric pressure in the reaction vessel C is lower than that in the plasma section, the mean free path becomes large. As a result, the reaction products do not collide and condense with each other, and the particle size of the reaction products does not grow large. The reaction product having a small particle size is immediately re-decomposed when diffused into the plasma, and does not reach the film-forming surface, so that a good film quality and a clean film surface can be obtained.
[0156]
The lower the atmospheric pressure in the reaction vessel C, the better the quality of the film and the clean the surface of the film can be obtained. Needless to say, the lower limit is the vacuum atmosphere.
[0157]
Considering the transport and removal of the reaction product generated in the local high-pressure plasma P by the flow along the sample surface in the minute interval D between the high-pressure floating electrode H1 and the sample J, The reaction product based on the high-pressure reaction gas is quickly moved from the local high-pressure plasma P by the flow along the sample surface, and the reaction gas exhaust port 4 provided in the high-pressure floating electrode H1 without stagnating in a certain area. Through the reaction gas exhaust device E. Thereby, the cleaning of the atmosphere on the film surface or in the reaction vessel is realized. At the same time, the reaction product is released into the vacuum or low-pressure atmosphere around the high-pressure floating electrode H1 without stagnation. By constantly evacuating the inside of the reaction vessel C and maintaining it at a vacuum or a certain pressure or less, it is possible to avoid condensation of the released reaction product with atmospheric particles and reattachment to the surface of the workpiece, The inside of the reaction vessel and the membrane surface can be cleaned.
[0158]
It is also possible to further provide a means for reprocessing the gas exhausted from the reaction vessel C and supplying the gas to the reaction vessel C again as a reaction gas or an ambient gas atmosphere in the reaction vessel C.
[0159]
Further, in the present embodiment, the prevention of the formation of the film deposition amount distribution immediately below the high-pressure reaction gas supply port 2 by installing the power transmission line open end 7 at a position away from the high-pressure reaction gas supply port 2 will be further described. I do.
[0160]
FIG. 7A is a cross-sectional view schematically showing a configuration near the high-pressure reaction gas supply port 2, and FIG. 7B is a cross-sectional view of the high-pressure reaction gas supply port using the configuration of FIG. FIG. 7C is a cross-sectional view showing a film thickness distribution formed immediately below the supply port 2 when the local high-pressure plasma P is generated in the vicinity including the gas supply port 2. It is a figure which shows the state of FIG. On the other hand, FIG. 8A schematically shows a configuration near the high-pressure reaction gas supply port 2 and the line open end 7 when the power transmission line open end 7 is installed at a position away from the high-pressure reaction gas supply port 2. 8B is a cross-sectional view. FIG. 8B is a cross-sectional view showing a case where local high-pressure plasma P is generated in the vicinity including the high-pressure reaction gas supply port 2 using the configuration of FIG. FIG. 8C is a diagram schematically showing a state of a gas flow generated in the minute gap D at the time of the above. 7B and FIG. 8B, reference numeral 1711 denotes a film-forming amount distribution formed immediately below the supply port 2 when the local high-pressure plasma P is generated near the high-pressure reaction gas supply port 2; Is a film thickness distribution formed immediately below the local high-pressure plasma P when the power transmission line open end 7 is installed at a position distant from the high-pressure reaction gas supply port 2 to generate the local high-pressure plasma P. 7A and FIG. 8A, reference numeral 1611 denotes a high-pressure reaction gas jet flowing out from the high-pressure reaction gas supply port 2, and reference numeral 1612 denotes a high-pressure reaction gas flowing along the sample surface in the minute interval D. In FIG. 7C and FIG. 8C, a reaction gas flow 1613 is a flow velocity distribution of the reaction gas which has become turbulent in the vicinity of the supply port 2, and 1614 is a shear gas flow away from the supply port 2. A flow rate distribution 1615 of the reaction gas changing into a flow is a flow velocity distribution of the reaction gas which is sufficiently separated from the supply port 2 and has become a shear flow.
[0161]
In the flow rate distribution of the high-pressure reactant gas in the minute interval D between the high-pressure floating electrode H1 and the sample J, a turbulent flow 1613 occurs immediately below and near the high-pressure reactant gas supply port 2, and the flow rate distribution is turbulent. And a non-steady flow that changes over time. In this case, there is a flow velocity distribution not only in the flow velocity distribution along the sample surface but also in a direction perpendicular to the sample surface. However, as the distance from the supply port 2 increases, the flow velocity distribution is gradually stabilized as indicated by 1614, and has only the flow velocity distribution in the direction along the sample surface. Eventually, as shown by 1615, a steady shear flow having only a flow velocity distribution along the sample surface depends on parameters such as the minute interval D and the flow velocity of the reaction gas. The flow velocity distribution U of the steady shear flow indicated by reference numeral 1615 is represented by the following equation (18):
[0162]
(Equation 18)

[0163]
Is represented by However, in the above equation (18), the coordinate origin is taken at the center of the minute interval D, and the x-axis is taken in a direction perpendicular to the sample surface. The flow velocity distribution in the along direction, Umax, is the origin, that is, the maximum flow velocity generated at the center of the minute interval D, and x is the distance from the origin.
[0164]
When plasma is generated on the entire surface of the sample facing portion 12 of the high-pressure floating electrode H1 including immediately below the high-pressure reaction gas supply port 2, the film formation region of the sample J is formed in a plasma generation region, that is, immediately below the high-pressure reaction gas supply port 2. And the entire surface of the high-pressure floating electrode H1 facing the sample. At this time, as shown in FIG. 7A, the jetted high-pressure reactant gas flow 1611 collides with the sample surface from a direction perpendicular to the sample surface, particularly immediately below the high-pressure reactant gas supply port 2, and time. An unstable turbulent flow whose flow velocity distribution changes is generated. Therefore, immediately below the reaction gas supply port 2, the amount of film formation is larger than in a region other than around the reaction gas supply port 2, where a flow 1612 (flow velocity distribution 1615) is formed along the sample surface. For this reason, a film formation amount distribution as indicated by 1711 in FIG. 7B is formed. Therefore, when the high-pressure floating electrode H1 is scanned to form a film on the entire surface of the sample, the film thickness distribution determined by the position of the high-pressure reactant gas supply port 2 and the trajectory of the scanning of the electrode H1 is changed. Formed on the film surface.
[0165]
Therefore, in the present embodiment, as shown in FIG. 8A, plasma is generated at the open end 7 of the power transmission line constituted by the inner electrode 5 and the outer electrode 6, thereby defining a plasma generation region. The local high-pressure plasma P is used. The local high-pressure plasma P is located at a position sufficiently distant from the high-pressure reactant gas supply port 2 and in a region where a stable shear flow 1615 is generated, so that the local high-pressure plasma P is located immediately below the high-pressure reactant gas supply port 2. The formation of the film deposition amount distribution 1711 is prevented and the flow along the sample surface in the minute interval D is used to form the film at the local high-pressure plasma P generation portion, thereby making the extremely stable processing amount distribution 1712 immediately below the local plasma. Get. By scanning the film formation region over the entire sample in this state, uniform film formation without a film formation amount distribution can be performed.
[0166]
In the surface treatment of the present invention, a local high-pressure plasma P is generated, a local film is formed near the plasma, and the electrode H1 and the sample J are relatively moved to form a film on the entire surface of the sample. I do. Further, the minute interval D is formed by the balance between the high pressure of the reaction gas in the minute interval D between the electrode H1 and the sample J, the electrode weight, and the low pressure or vacuum atmosphere in the reaction vessel C. Therefore, it is desirable to use a deformable flexible power transmission line I as the power transmission line connecting the resonance / matching device M and the electrode floating type high-voltage floating electrode H1. The connection between the flexible power transmission line I and the high-voltage floating electrode H1 is made by the connector 8, and this connection must be made so that there is no loss due to contact resistance at the connection portion and no leakage of electromagnetic waves.
[0167]
The insulator 11 is preferably made of a material that is not corroded by the local high-pressure plasma P generated at the open end 7 of the power transmission line, for example, high-purity alumina, silicon nitride, or the like. It is desirable to use a material containing at least one kind of constituent elements. For example, when a Si film is formed, the use of silicon nitride (SiN) for the insulator 11 can reduce the amount of impurities mixed into the film.
[0168]
When the fixing jig for fixing the sample J with respect to the sample fixing portion F projects to a portion facing the high-voltage floating electrode H1, the high-pressure floating electrode H1 and the sample J are very close to each other as described above. This causes undesired states such as damage to the sample facing portion 12 of the high-voltage floating electrode H1 and a change in the pressure distribution within the minute interval D. Therefore, it is desirable to use a mechanism such as a vacuum chuck or an electrostatic chuck that does not allow the sample fixing jig or the like to protrude from the electrode facing portion as the sample fixing portion F.
[0169]
Further, the step t between the sample J and the sample table T shown in FIG. 4 changes the pressure distribution of the high-pressure reaction gas within the minute interval D, causing the electrode levitation type high-pressure levitation electrode H1 to be inclined with respect to the sample J, Furthermore, in order to cause problems such as a change in the film-forming speed distribution and contact of the sample with the electrode surface, it is necessary to minimize the distribution.
[0170]
Corrosion-resistant and high-hardness insulating film, such as alumina sprayed film, is formed on the sample facing portion 12 of the high-voltage floating electrode H1 and flattened with high precision, thereby reducing corrosion of the sample facing portion 12 due to plasma. As a result, it is also possible to realize a high-voltage floating electrode having a longer life.
[0171]
As shown in FIG. 9, a highly accurate flattened corrosion-resistant and hardened insulator 18, for example, an insulator 18 made of high-purity alumina or silicon nitride, which is flattened with high accuracy, is attached to the entirety of the sample facing portion 12. It is also possible to use a corrosion-resistant and high-hardness insulating material for which film formation is difficult for the sample facing portion 12.
[0172]
Alternatively, as shown in FIG. 10, by using a porous material 19, for example, porous alumina or the like for the reaction gas supply port 2, it is possible to control the narrow gap interval D between the electrode H1 and the sample J very stably. It is also possible to realize a high-pressure floating electrode H1 that enables the following.
[0173]
In the high-pressure floating electrode H1, the positions and the numbers of the high-pressure reaction gas supply port 2 and the reaction gas exhaust port 4 are not limited to one. For example, as shown in FIG. 11, the high-pressure reaction gas supply port 2 and the reaction gas exhaust port 4 can be provided on the sample table T or on both the high-pressure floating electrode H1 and the sample table T.
[0174]
The scanning stage S described above with reference to FIG. 1 can have a vertical movement mechanism, a horizontal movement mechanism, a rotation mechanism, and the like according to the purpose. Further, the number of the samples J fixed to the sample table T is not limited to one. By performing batch processing using a sample stage on which a large number of samples are fixed, production efficiency can be improved.
[0175]
For example, FIG. 12 is a conceptual diagram showing a batch process using a multi-sample fixing sample stage T11 having multiple rotation axes and rotation speeds. In FIG. 12, T11 is a sample stage for fixing many samples.
[0176]
In the configuration example shown in FIG. 12, a sample stage T11 having a rotation mechanism θ1 is installed on a scanning stage S capable of performing multi-directional scanning in the XYZ directions, and a rotation stage of the sample stage T11 is further mounted on T11. A large number of sample tables T each having a rotation mechanism θ of the same or different rotation number, rotation direction, and rotation axis as the mechanism θ1 are installed. The sample J is placed on each sample table T, and the electrode floating type high-voltage floating electrode H1 is opposed to the sample J to perform batch processing. At this time, the sample J is scanned by scanning the electrode H1 through the scanning wire or the belt 9 and by performing multi-directional scanning of the scanning stage S or performing random processing using the rotation mechanism of the sample stage T and the sample stage T11. Each film can be formed uniformly, and film formation with extremely high film uniformity can be performed, and at the same time, production efficiency can be improved by batch processing.
[0177]
The shape of the high-pressure reaction gas supply port 2 for supplying the high-pressure reaction gas to the minute interval D between the high-pressure floating electrode H1 and the sample J, the reaction product exhaust port 4, and the sample facing portion 12 of the high-pressure floating electrode H1 is the same as that of the sample J. The shape, size, finishing accuracy, and the like vary depending on the intended film formation. The embodiment of the high-voltage floating electrode H1 is not limited to this.
[0178]
It should be noted that a high-pressure portion may be formed in the reaction vessel C for positioning the sample or the like in the horizontal direction. However, the high pressure portion in that case is not included in the “ambient gas atmosphere portion having a pressure lower than the supply pressure” described above.
[0179]
(Second embodiment)
Next, a second embodiment of the present invention using the sample floating type high-voltage floating electrode H2 will be described below.
[0180]
The sample levitation type high-voltage levitation electrode H2 in the present embodiment is a high-voltage levitation electrode using a method in which a levitation sample A is levitated with respect to an electrode capable of generating local high-pressure plasma P by transmitting power from a power supply G. . In this case, the sample floating type high-voltage floating electrode H2 is installed in the reaction vessel C, and the floating sample A is floating.
[0181]
FIG. 13 is a schematic cross-sectional view of the sample floating high-voltage floating electrode H2, where A is a floating sample, H2 is a sample floating high-voltage floating electrode, and Y is a floating sample scanning wire or belt. The sample levitation type high-voltage levitation electrode H2 is set on a scanning stage S (not shown in FIG. 13), and the sample levitation type high-pressure levitation electrode H2 is scanned by the scanning stage S. The relative position with respect to the flying sample A can be changed.
[0182]
The floating sample scanning wire or belt Y is connected to a drive motor 10 not shown in FIG. Thus, similarly to the electrode levitation type high voltage levitation electrode H1, by rotating the drive motor 10, the levitation sample A is scanned to change the relative position between the sample levitation type high voltage levitation electrode H2 and the levitation sample A. Can be. The drive motor 10 and the floating sample scanning wire or belt Y are collectively called a sample stage scanning device.
[0183]
As described above, the present embodiment uses the sample levitation method in which the levitation sample A is floated by the minute interval D with respect to the sample levitation type high pressure levitation electrode H2 that generates the local high-pressure plasma P. Similarly to the electrode levitation type high pressure levitation electrode H1, a local film is formed in the vicinity of the local high pressure plasma P of the floating sample A by an active species based on the high pressure reaction gas in the local high pressure plasma P generated during the minute interval D. Do. Further, the entire film is formed on the surface of the sample A by changing the relative positions of the sample floating type high-voltage floating electrode H2 and the floating sample A using the scanning stage S and the sample stage scanning device. Further, in the present embodiment, the shape and position of the high-pressure reaction gas supply port 2, the shape and position of the reaction product exhaust port 4, and the power transmission described in the first embodiment with respect to the electrode floating type high-pressure floating electrode H 1. The shape, position and structure of the line open end 7 are the same as in the first embodiment. In particular, in the present embodiment, the sample A can be floated together with the sample stage T with a relatively low supply pressure for a light sample A such as a glass substrate. Thus, the pressure condition of the processing conditions can be set broadly, and at the same time, the sample A can be transported relatively easily, so that the productivity of the entire apparatus can be improved.
[0184]
In addition, the configuration of the entire apparatus not shown in FIG. 13, the floating principle and method of the floating sample A, the generation principle and method of the local high-pressure plasma P, the film forming phenomenon in the local high-pressure plasma P, the high film forming speed, the film quality improvement, and The principle and method for simultaneously realizing the surface cleaning after film formation, the local high-pressure plasma P is generated at a position distant from the high-pressure reaction gas supply port 2, and the film formation amount distribution 1711 immediately below the high-pressure reaction gas supply port 2 is obtained. The principle and method of preventing the formation can be applied to the present embodiment, similarly to the electrode floating type high-voltage floating electrode H1.
[0185]
Further, the shape of the high-voltage floating electrode H1 described in the first embodiment, the formation of a corrosion-resistant and high-hardness insulating film on the sample facing portion 12 of the high-voltage floating electrode H1 and the high-voltage floating electrode shown in FIG. Installation of high-precision flattening corrosion-resistant and high-hardness insulating material 18 on sample facing portion 12 of electrode H1, installation of porous material on high-pressure reactant gas supply port 2 shown in FIG. 10, multi-rotation axis and rotation shown in FIG. The features relating to the batch processing method using a large number of sample holders T11 for fixing a large number of samples, the configuration of the sample stage T, the sample fixing portion F, and the like are similarly applied to the sample floating type high-voltage floating electrode H2 of the present embodiment. be able to.
[0186]
Alternatively, in the sample-floating high-pressure floating electrode H2 as shown in FIG. 14, the positions and quantities of the high-pressure reaction gas supply port 2 and the reaction product exhaust port 4 are not limited to one. It is also possible to install on both the electrode H2 and the sample stage T.
[0187]
FIG. 15 shows a configuration in which the floating body in the sample floating type high-voltage floating electrode H2 is only the floating sample A instead of the sample table T to which the floating sample A shown in FIG. 13 is fixed.
[0188]
In FIG. 15, Y11 is a floating sample restraining scanning mechanism capable of restraining or scanning the floating sample A, and without connecting the scanning wire or the belt Y directly to the floating sample A, separately from the floating direction of the floating sample A. This is a mechanism for scanning the floating sample A by pressing the floating sample more.
[0189]
According to this configuration, the chucking time of the sample in the electrode levitation type high voltage levitation electrode H1 or the sample levitation type high voltage levitation electrode H2 can be omitted. Therefore, the productivity of the process can be improved by moving the floating sample in one direction by such a floating sample constrained scanning mechanism, forming a film in a flowing manner, and then transferring the sample.
[0190]
(Third embodiment)
Next, a description will be given of a third embodiment of the present invention using an electrode floating type high-voltage floating electrode H3 using a waveguide as a power transmission line.
[0191]
When a waveguide is used for a power transmission line, the power transmission line cannot transmit DC and AC having a low frequency. Therefore, as the power source G, a high frequency having a frequency of at least 10 MHz to 1 GHz or a microwave power source G11 having a frequency of 1 GHz or more is used.
[0192]
FIG. 16 is a cross-sectional view of an electrode floating type high-voltage floating electrode H3 using a waveguide as the power transmission line, and FIG. 17 is a partial cross-sectional view of the electrode H3 viewed from another direction, FIGS. 18A and 18B. FIG. 4 is a lower slope view and an upper slope view of the electrode H3.
[0193]
In FIG. 16, reference numeral H3 denotes an electrode floating type high-voltage floating electrode using a waveguide as the power transmission line, P denotes a local high-pressure plasma, 24 denotes a high electric field by applying a microwave, and an electrode H3-sample J The open end 21 of the waveguide for generating a local high-pressure plasma P at a minute interval D between the resonance-matching device M for boosting and matching the microwave supplied from the microwave power source G11 as necessary, A flexible waveguide for transmitting microwaves to the floating electrode H3, an in-electrode waveguide 22 for transmitting microwaves from the flexible waveguide 21 to the waveguide open end 24 located at the sample facing portion 28 of the electrode H3, 23 is an insulator that separates the internal space of the in-electrode waveguide 22 from the high-pressure reactant gas region at the minute interval D between the electrode H3 and the sample J, 20 functions as a high-pressure reactant gas supply port, Jo is pressure reaction gas supply slit is a slit shape.
[0194]
In FIG. 17, T12 is a concave sample stage that has a concave shape, fixes the sample J on the inner bottom surface of the concave portion, and restricts the movement of the electrode H3 on the inner side wall of the concave portion. Reference numeral 25 denotes a high-pressure gas supply port, which is provided on the inner side wall of the concave sample stage T12 and restricts the movement direction of the electrode H3 in one direction without contacting the electrode H3 by the high-pressure gas ejected from the supply port. Reference numeral 26 denotes a high-pressure gas supply path that transports high-pressure gas from a high-pressure gas supply device (not shown) to the high-pressure gas supply port 25.
[0195]
In FIG. 18A, reference numeral 27 denotes a sample gas flowing through the minute interval D between the electrode H3 and the sample J from the high-pressure reaction gas supply slit 20 to the reaction gas exhaust port 4 or toward the gas atmosphere around the electrode H3. It is a flow.
[0196]
In each of these figures, the sample J, the sample fixing portion F, the high-pressure reaction gas supply path 1, the reaction product exhaust path 3, and the reaction product exhaust port 4 are formed by the inner electrode 5, the outer electrode 6, and the insulator 11. The configuration is the same as that of the high-voltage floating electrode H1 or H2 constituting the in-electrode power transmission line. The scanning stage S, reaction vessel C, power supply G, power transmission line K, resonance / matching device M, high-pressure reaction gas supply device R, exhaust device E, high-pressure floating electrode scanning device U, and control device N (not shown) The configuration is the same as that of the floating electrode H1 or H2. However, instead of the power supply G, a high frequency or microwave power supply G11 is used.
[0197]
The following describes the configuration of the electrode levitation type high-voltage levitation electrode H3 using the waveguide as the power transmission line, the levitation method of the high-voltage levitation electrode H3, the film formation method of the high-voltage levitation electrode H3, and the use of the waveguide for the power transmission line. And the effect of using the microwave power supply G11 will be described in order.
[0198]
First, the electrode levitation type high-voltage levitation electrode H3 using a waveguide as a power transmission line will be described again. As shown in FIGS. 18A and 18B, the electrode H3 faces the sample J in a metal cube. One surface is flattened with high precision, and the surface is used as a sample facing portion 28 of the electrode floating type high voltage floating electrode H3. Further, an in-electrode waveguide 22 capable of transmitting microwave power is provided inside the metal cube, and the waveguide 22 is open-ended toward a desired position in the sample facing portion 28. The internal space of the open-terminated in-electrode waveguide 22 is closed by the insulator 23, and separated from the gas atmosphere around the electrode floating type high-voltage floating electrode H3. A portion of the in-electrode waveguide 22 which is open-ended at the sample facing portion 28 is referred to as a waveguide open end 24. By connecting the flexible waveguide 21 to the in-electrode waveguide 22 from the direction opposite to the waveguide open end 24, the microwave power generated from the power source G11 can be used to convert the microwave power generated from the power source G11 into the electrode in the electrode floating type high-voltage floating electrode H3. The light is transmitted to the inner waveguide 22 and further to the waveguide open end 24. As a result, a local high-pressure plasma P is generated at the position of the waveguide open end 24.
[0199]
Here, the insulator 23 is desirably made of a material having high hardness and corrosion resistance to the local high-pressure plasma P. Examples of such a material include high-purity alumina and silicon nitride. Further, as the case may be, when a material containing at least one or more elements constituting the film forming material, for example, a Si film is formed, silicon nitride is used for the insulator 23 to prevent impurities from entering the film. It is desirable to reduce it. Even after the insulator 23 is installed, it is desirable to perform the flattening again until the sample facing portion 28 becomes a highly accurate flat surface. Further, a high-pressure reactant gas supply slit 20 for ejecting a high-pressure reactant gas is opened in the sample facing portion 28, and the position thereof is set at a position apart from the waveguide open end 24. A high-pressure reaction gas is supplied from the high-pressure reaction gas supply device R to the high-pressure reaction gas supply slit 20 through the high-pressure reaction gas supply path 1, and the high-pressure reaction gas supply slit 20 ejects the high-pressure reaction gas. Further, at the sample facing portion 28 and at a position between the high-pressure reaction gas supply slit 20 and the waveguide open end 24, it is connected to the exhaust device E through the reaction product exhaust path 3, A reaction product exhaust port 4 for exhausting the reaction product generated by the above reaction is provided.
[0200]
Here, as shown in FIG. 18A and FIG. 18B, the reaction product exhaust port 4 and the waveguide open end 24 have a wide slit shape, and the slit 20, the reaction product exhaust port 4, The waveguide open ends 24 are placed in a parallel relationship with each other.
[0201]
Next, the floating method of the high-voltage floating electrode H3 will be described.
[0202]
As shown in FIG. 17, the high-voltage floating electrode H3 is fitted into the concave portion of the concave sample stage T12 to which the sample J is fixed, while keeping the two in a non-contact state. By ejecting the high-pressure reaction gas from the high-pressure reaction gas supply device R through the high-pressure reaction gas supply slit 20 through the high-pressure reaction gas supply path 1, the high-pressure reaction gas rises due to the pressure difference between the high-pressure reaction gas and the gas atmosphere in the reaction vessel C. The electrode H3 is floated at a minute interval D with respect to the sample J. Therefore, the concave sample stage T12, the sample J, and the sample facing portion 28 of the high-voltage floating electrode H3 maintain a non-contact state. Further, the inner concave side surface 63 of the concave sample stage T12 and the side surface 62 of the high-voltage floating electrode H3 facing the inner side surface are flattened with high precision. Further, the width Q12 of the concave portion of the concave sample stage T12 is slightly larger than the width Q11 of the high-pressure floating electrode H3, and the high-pressure gas is ejected from the high-pressure gas supply port 25 through the high-pressure gas supply path 26 from the high-pressure gas supply device (not shown). Thereby, the inner concave side surface 63 of the concave sample stage T12 and the side surface 62 of the high-voltage floating electrode H3 facing the inner side surface are kept in a non-contact state, and the movement direction of the high-voltage floating electrode H3 is further limited to one direction. That is, the electrode floating type high-voltage floating electrode H3 using the waveguide as the power transmission line only employs the in-electrode waveguide 22 as the power transmission line. Similarly to the electrode levitation type high pressure levitation electrode H1, the pressure difference between the high pressure P0 of the reaction gas supplied from the high pressure reaction gas supply slit 20 and the low pressure or vacuum atmosphere pressure P1 in the reaction vessel C exhausted by the exhaust device E. As a result, it floats by the minute interval D. By forming the high-pressure reaction gas supply port into a slit shape and further arranging the slit 20 and the reaction product exhaust port 4 in a parallel relationship with each other, the flow of the high-pressure reaction gas from the supply slit 20 to the reaction gas exhaust port 4 is reduced. In addition, the flow velocity distribution in the longitudinal direction of the slit 20 can be made uniform. By thus making the flow velocity distribution uniform, the film forming velocity distribution in the local high-pressure plasma P generated at the waveguide open end 24 can be made uniform.
[0203]
Next, a film forming method using the electrode H3 of the present embodiment will be described.
[0204]
The microwave power generated from the microwave power source G11 is passed through the resonance / matching device M, the flexible waveguide 21, and the in-electrode waveguide 22 to open the waveguide provided on the sample facing portion 28 of the high-voltage floating electrode H3. End 24 is reached. The microwave power reaching the waveguide open end 24 is radiated toward the high-pressure reactant gas in the minute interval D between the electrode H3 and the sample J. Thereby, the high-pressure reaction gas is dissociated, and a local high-pressure plasma P based on the reaction gas is generated. Further, a film is formed on the sample J just below the local high-pressure plasma P by an active species based on the reaction gas generated in the plasma P.
[0205]
Here, the cross-sectional shape of the waveguide 22 is determined by the frequency of the microwave power supply G11, the sample J, the target film formation characteristics, and the film formation region.
[0206]
Furthermore, the reaction gas supplied from the high-pressure reaction gas supply slit 20 is supplied to the electrode H3 formed by the floating of the electrode H3 toward the low-pressure or vacuum atmosphere in the reaction vessel C and the reaction gas exhaust port 4, and the electrode H3 is processed. In the minute interval D between the objects J, it moves as a flow 27 along the sample surface. Further, by providing the open end 24 of the power transmission line using the waveguide in the sample facing portion 28 and at a position sandwiched between the reaction gas exhaust ports 4 distant from the high pressure reaction gas supply slit 20, the high pressure reaction gas A local high-pressure plasma P is formed in the flow along the sample surface, and a uniform film is formed on the surface in a flow field of the reaction gas without stagnation.
[0207]
Next, the effect of using the waveguide for the power transmission line will be described.
[0208]
In the embodiment in which the power transmission line is configured using the inner electrode 5 and the outer electrode 6 such as the electrodes H1 and H2, not only the microwave power source G11 but also all frequencies from DC to microwave power source are provided for the power source G. Of power can be used. However, the insulation between the inner electrode 5 and the outer electrode 6 and the separation between the power transmission portion surrounded by the inner electrode 5 and the outer electrode 6 and the reaction gas region in the minute gap D between the electrode and the workpiece are not required. It is necessary that the insulator 11 to be mounted is attached with no gap to the outer diameter of the inner electrode 5 and the inner diameter of the outer electrode 6. In this case, the heat generated from the generated local high-pressure plasma P thermally deforms the inner electrode 5 and the outer electrode 6, and there is a possibility that the thermal expansion of the inner electrode 5 may damage the insulator 11. Therefore, the outer electrode 6 and the inner electrode 5 are cooled, but in reality, the high-pressure floating electrode H1 or H2 having such a complicated structure is manufactured, and the entire electrode H1 or H2 is uniformly cooled. Providing a mechanism is very difficult.
[0209]
However, in the present embodiment, by using a waveguide for the power transmission line, there is no distinction between the inner electrode 5 for applying a voltage and the outer electrode 6 for confining an electric field. The power transmission line inside the electrode and the cooling path inside the electrode are easily manufactured. In addition, since the metal structure surrounds the insulator 23, the coefficient of thermal expansion of the metal is generally larger than the coefficient of thermal expansion of the insulator. The body 23 is hardly damaged.
[0210]
The effect obtained by using the microwave power supply G11 as the power supply will be described. Table 5 below shows the maximum electric field intensity E0 and the oscillating electric field E = E0 · sin (2πft) that periodically changes with the frequency f. (Where t is time), the vibration amplitude L when various charged particles (charge amount e, mass m) vibrate in a vacuum L = (e · E0 / 4mπ)²f²4) is a table showing the values of the above. However, when the electric field strength is 1.0 × 10⁶[V / m].
[0211]
[Table 5]

[0212]
FIG. 19A is a conceptual diagram illustrating a vibration amplitude L of the charged particles 29 caused by the vibration electric field E (see FIG. 19B).
[0213]
As shown in Table 5, the vibration amplitude L of the vibration electric field E decreases as the frequency increases. Although the minute interval D is a narrow gap of about 1 μm to several hundred μm, if a high-frequency power supply having a frequency of about 1 MHz is used as a power supply for generating the local high-pressure plasma P, the vibration amplitude L thereby becomes 0 in the case of He ions. .607 [m], which is very large. As a result, charged particles cannot be trapped in the narrow gap, and as a result, the charged particles collide with the sample surface and the film surface during film formation to damage the film, resulting in a film having a high defect density.
[0214]
However, when the minute interval D between the electrode and the sample is about several hundred μm, a high frequency of at least 10 MHz is used as a power source for generating the local high-pressure plasma P, while when the minute interval D is about several tens μm, the frequency is 1 GHz or more. By using the microwave, the charged particles are reliably captured in the minute interval D between the electrode and the sample, and a low-damage film formation that does not damage the film can be realized.
[0215]
As shown in FIG. 17, in relative movement between the sample J and the high-voltage floating electrode H3, the sample J is fixed to the inner bottom of the concave sample stage T12 by the sample fixing portion F, and the inner side surface 63 of the sample stage T12 is moved. The scanning direction of the high-pressure floating electrode H3 is limited to only the direction horizontal to the sample J in a non-contact manner without using a sliding portion in an air-slide manner by the high-pressure gas ejected from the high-pressure gas supply port 25 installed in the sample. Further, scanning in a direction horizontal to the sample J is performed by connecting a scanning wire or a belt 9 connected to the high-voltage floating electrode H3 to a drive motor 10 (not shown) and rotating the drive motor.
[0216]
The high-pressure gas ejected from the high-pressure gas supply port 25 is not limited to the high-pressure reaction gas used for forming the film of the sample J, and may be changed according to the purpose, such as a highly insulating gas, a rare gas, or air.
[0217]
(Fourth embodiment)
Next, a fourth embodiment of the present invention will be described.
[0218]
FIG. 20A, FIG. 20B, and FIG. 20C are a cross-sectional view, a front view, and a top view, respectively, of a sample floating high-voltage floating electrode using a waveguide as a power transmission line. In these figures, H4 is a sample floating type high-voltage floating electrode using a waveguide as a power transmission line, 30 is a floating sample feeding belt with a projection, 31 is a projection of a feeding belt, and 32 is a floating sample feeding belt. It is a feed motor.
[0219]
The sample floating type high pressure floating electrode H4 using the waveguide for the power transmission line is the same as the electrode floating type high pressure floating electrode H3 using the waveguide for the power transmission line described in the previous embodiment. Microwaves are transmitted by a tube, and local high-pressure plasma P is generated at a waveguide open end 24 provided at a sample facing portion of the electrode H4. Then, the high-pressure reaction gas supplied during the minute interval D is decomposed, and active species based on the reaction gas are generated to form a film on the surface of the floating sample A. Further, a film is uniformly formed on the surface of the sample A by the flow of the reaction gas along the sample surface in the minute interval D between the electrode H4 and the sample A. As in the case of the sample levitation high pressure levitation electrode H2, the chucking time of the samples J and A in the electrode levitation high pressure levitation electrode H1 and the sample levitation high pressure levitation electrode of FIG. 14 can be omitted. By performing the processing and the sample transfer, the productivity of the process can be further improved.
[0220]
20A, 20B, and 20C, the entire apparatus not shown in FIG. 20A, FIG. 20B, and FIG. 20C, the floating principle of the sample, the plasma generation method, and the local plasma. The principle and method for simultaneously realizing the film formation phenomenon, high film formation rate, improvement in film quality, and cleaning of the surface of the sample after film formation are the same as those of the electrode floating type high pressure floating electrode H1 described above.
[0221]
Although not shown, it is also possible to implement a method in which the sample is fixed to a sample stage and the sample floats together with the sample stage as shown in FIG.
[0222]
As shown in FIG. 20C, the scanning of the floating sample is performed by the motor 32 at both ends while the sample is fixed by the projection 31 by the floating sample feed belt 30 having the projection 31 whose both ends are restrained and rotated by the floating sample feed motor 32. By rotating, a mechanism that sends the sample in one direction or scans the sample back and forth can also be used.
[0223]
(Fifth embodiment)
Next, a fifth embodiment of the present invention will be described.
[0224]
FIG. 21 is a partial cross-sectional view of a high-voltage floating electrode for forming a film on a sample whose surface has a spherical surface. In FIG. 21, H5 is a high-pressure floating electrode having a spherical shape at the sample facing portion, T13 is a sample stage for fixing a spherical sample, B is a sample having a spherical surface on which a film is formed, and 60 is a sample for fixing a spherical sample. The electrode-facing surface 61 of the table T13 is a sample-facing portion of the high-voltage floating electrode H5.
[0225]
When forming a film on the sample B having a spherical surface, the electrode-facing surface 60 of the spherical sample-fixing sample stage T13 is spherical, and its radius is made to match the spherical radius of the sample B. The sample B is set so that the spherical surface of the film forming surface thereof overlaps the spherical surface of the electrode facing surface 60 of the sample stage T13 without any step. On the other hand, the shape of the sample-facing portion 61 of the high-voltage floating electrode H5 is also made to be spherical, and its radius is made equal to or larger than the spherical radius of the sample B. In this state, the sample-facing portion 61 of the high-pressure floating electrode H5 and the spherical surface of the sample B face each other, and the high-pressure reaction gas supplied from the high-pressure reaction gas supply port using the porous material 19 and the low-pressure and The high-pressure floating electrode H5 is floated from the surface of the sample B by a minute interval D due to the pressure difference from the vacuum atmosphere.
[0226]
Although not shown, it is also possible to cause the sample B to float by a minute interval D from the high-pressure floating electrode H5 by the differential pressure between the high-pressure reaction gas supplied from the high-pressure reaction gas supply port and the low pressure and vacuum atmosphere in the reaction vessel. is there.
[0227]
The plasma is generated by transmitting a DC or AC voltage generated from a power supply G (not shown) to the power transmission line open end 7 provided on the sample facing surface of the electrode H5, like the high-pressure floating electrode H1, to supply a high-pressure reaction gas. A local high-pressure plasma P is generated by generating a strong electric field in the minute interval D between the electrode H5 and the sample B, and a film is formed on the sample B by an active species based on the reaction gas.
[0228]
In the configuration of FIG. 21, the power transmission line is constituted by the inner electrode 5 and the outer electrode 6, and transmits DC or AC generated from the power supply G to the power transmission line open end 7 and further to the local high-pressure plasma P. I have. Alternatively, when the power supply is a microwave power supply, for example, the microwave is transmitted using a waveguide as shown in FIG. 16 in relation to the above embodiment, and further, the sample facing portion 28 shown in FIG. Is formed into a spherical surface as shown in the sample facing portion 61 of the high-voltage floating electrode H5, and a strong electric field is generated at the open end of the waveguide similarly installed in the portion facing the sample to generate a local high-pressure plasma P. What is necessary is just to form a film on the sample B.
[0229]
The shape and position of the high-pressure reactant gas supply port indicated by the electrode levitation type high-pressure levitation electrode H1, the sample levitation type high-pressure levitation electrodes H2 and H3, and the high-pressure levitation electrode H4 using a waveguide as a microwave transmission line, and reaction product exhaust. Mouth shape and position, microwave open end shape and position, high-voltage floating electrode shape, sample facing part corrosion-resistant and high-hardness insulating film formation and sample facing part corrosion-resistant and high-hardness insulating material installation, sample stage, sample fixing part, etc. The feature can be similarly applied to the high-voltage floating electrode H5 in the case where the film formation surface shape of the sample is spherical as in this embodiment.
[0230]
In the description of each embodiment of the present invention, the case where the film is formed according to the present invention has been mainly described, but the present invention can be similarly applied to the case where the surface is modified.
[0231]
【The invention's effect】
As described above, according to the present invention, a sample and an electrode to which electric power is applied are arranged to face each other in a desired gas atmosphere, and plasma is locally generated by applying electric power. At this time, the surface treatment (for example, film formation or surface treatment) is performed on the sample surface with high efficiency by maintaining only the local plasma generating portion at a high pressure. At the same time, by maintaining the desired gaseous atmosphere pressure at least lower than that of the local high-pressure plasma generating section or in a vacuum, the reaction product does not condense and does not adhere again to the sample surface, and a good quality film is formed. Alternatively, a surface treatment can be performed. In addition, by limiting the plasma generation region to a region other than the reaction gas ejection region near the reaction gas supply port at the electrode-sample interval and in a region where the flow of the reaction gas along the sample surface is formed. During the film forming process, the sample does not form a film thickness distribution just below the reaction gas ejection region, or during the surface treatment, the treatment layer thickness distribution does not form immediately below the reaction gas ejection region. Surface treatment (film formation or surface modification) of the surface can be performed.
[0232]
Furthermore, according to the present invention, by generating plasma in the locally formed high-pressure reaction gas region, it is possible to form a film at a high speed on a sample, and at the same time, to locally generate high pressure while the plasma is generated. By maintaining the pressure in the region other than the high-pressure reaction gas region at a pressure lower than that of the high-pressure reaction gas region, condensation of reaction products in the atmosphere around the sample is reduced, a good-quality film can be formed, and the film surface can be kept clean. Can be.
[0233]
According to the present invention, the ratio px / p0 of the pressure p0 of the portion where plasma is generated in the high-pressure gas atmosphere locally maintained in the low-conductance flow path portion to the pressure p0 of the gas atmosphere in which the sample is disposed is defined. By setting px / p0> 1, high-density active species are generated in the plasma portion to achieve a high deposition rate. At the same time, since the pressure of the surrounding atmosphere is lower than that of the plasma part, condensation of reaction products in the surrounding atmosphere of the sample can be further reduced, and a good quality film can be formed, and the film surface can be kept clean.
[0234]
Further, according to the present invention, by setting the area other than the locally high-pressure part where plasma is generated to a pressure of 1 atm or less, it becomes difficult for the reaction gas to diffuse into the atmosphere, and the safety of the apparatus is improved. Can be increased.
[0235]
Further, according to the present invention, the region other than the locally high-pressure portion where the plasma is generated is further made into a vacuum atmosphere, so that the particle size and the number of the reaction products in the atmosphere around the workpiece are reduced. The absolute value can be reduced, a good quality film can be formed, and the film surface can be further kept clean. At the same time, the atmosphere is kept in a vacuum at the time of purging when the sample is carried out to the atmosphere, so that it is not necessary to exhaust the reaction gas each time, and the throughput of the apparatus can be improved.
[0236]
Further, according to the present invention, a local high-pressure plasma is generated in a specific region in a high-pressure reaction gas region locally formed in a low conductance flow path portion, thereby locally forming a plasma at a desired position. A membrane can be made.
[0237]
In addition, by providing a region where the local high-pressure plasma is generated and a film is formed on the sample surface at a position away from the portion where the reaction gas is supplied, it is possible to prevent the formation of a film thickness distribution immediately below the portion where the reaction gas is supplied, and to achieve uniformity. It is possible to carry out a proper film formation.
[0238]
Further, in an electrode and a sample table having a shape corresponding to the sample and further having at least one of a high-pressure reaction gas supply port, the electrode and the sample are disposed at a small interval, so that the electrode is moved from the supply port. The above-described high-pressure reaction gas region can be locally formed as a wall surface forming a low conductance portion of a gas flow path to a gas atmosphere. Further, if power is applied to the electrode to generate plasma at a minute interval between the electrode and the sample, which has locally become a high-pressure reaction gas due to low conductance, high-speed and high-quality film formation is performed on the sample. And the film surface can be kept clean.
[0239]
In addition, due to the pressure difference between the high-pressure reaction gas region locally formed by the pressure of the high-pressure reaction gas supplied from the supply port and the gas atmosphere pressure, the electrode is moved to the sample or the sample is moved to the electrode. By floating at a small distance, low conductance can be obtained even in an environment where it is difficult to measure and control the minute distance due to the deformation of the electrode or sample due to the heat of the plasma, or the presence of an electric field or corrosive gas that generates the plasma. A small gap can be formed in a wide area with a stable gas flow path stably. In addition, the electrodes can be arranged without being inclined with respect to the sample, and the uniformity of the flow rate distribution of the reaction gas can improve the uniformity of the film thickness.
[0240]
Further, a magnetic body or a magnetic force generating mechanism is provided on at least one of the electrode and the sample stage, and the magnetic force generated by the magnetic body or the magnetic force generating mechanism causes the electrode to be placed on the sample or the sample on the electrode. By levitating at a small interval, a gas channel with low conductance can be formed in a wide area stably. Furthermore, by using a newly generated magnetic force generating mechanism or a magnetic force generated from a magnetic material as a force for floating the electrode or the sample, the reaction gas pressure range can be set broadly, and not depending on the electrode weight but on the intended film forming characteristics. The supply pressure of the reaction gas can be determined.
[0241]
Further, a power transmission line is further provided in the electrode, and the power transmission line open end is provided in a portion facing the sample, so that the power applied to the electrode is transmitted to the power transmission line open end, and the open end of the open end is provided. Plasma can be locally generated only in the vicinity. Further, since the power transmission line is terminated by the plasma, the equivalent circuit of the power supply mechanism does not change even when the electrode and the sample are relatively moved to form the entire surface of the sample. As a result, the influence on the plasma is small, and the film can be more uniformly formed over a wide area.
[0242]
In addition, by using microwave power as the power to generate plasma, charged particles in the plasma generated at minute intervals between the electrode and the sample are reliably captured at minute intervals, and the sample surface and the formed film Can be further reduced. At the same time, plasma can be generated between the electrode and the sample kept at a minute interval.
[0243]
In addition, since the power transmission line in the electrode is a waveguide, the configuration of the electrode can be simplified, and the reliability of the device can be improved by preventing damage to the electrode itself due to deformation of the electrode due to the heat of plasma. In addition, the device cost can be reduced by simplifying the component shape.
[0244]
An electrode or a sample stage is provided with a reaction product exhaust port that opens toward a minute gap where plasma is generated, and a reaction product generated in the plasma is immediately exhausted from this exhaust port, thereby forming a good quality film on the sample. It can be formed and the membrane surface can be kept even cleaner.
[0245]
In addition, the electrode having a shape including a shape similar to the sample surface at least in the shape of the portion facing the sample with respect to the sample is used. A local plasma is generated in the flow along the sample surface from the part to the gas atmosphere around the electrode or toward the reaction gas exhaust port, and the active species based on the reaction gas generated by this plasma generates a steady flow along the sample surface along the sample surface. In addition, a film can be uniformly formed on a sample.
[0246]
In addition, a power absorber having a large absorption coefficient for electromagnetic waves of a frequency of a power supply to be used is provided on at least one of the electrode and the sample stage in a low conductance flow path that flows from the reaction gas supply unit to the surrounding gas atmosphere. By providing the low-pressure side of the region where the local high-pressure plasma is generated, it absorbs electromagnetic waves that have not been consumed by the local high-pressure plasma and passes through the low-pressure gas atmosphere outside the local high-pressure atmosphere. It can be prevented from occurring.
[0247]
In addition, a film can be formed over a large area on a sample by relatively moving an electrode for generating plasma and the sample, and a desired film thickness distribution can be formed by controlling a scanning speed. Can be membrane.
[0248]
In addition, the gas atmosphere in the reaction vessel is exhausted, and further supplied as a reaction gas or a gas atmosphere in the reaction vessel after the processing, so that the reaction gas and the atmosphere gas are not wasted and the film formation cost is reduced. be able to.
[0249]
It is possible to apply a wide range of power from DC to low frequency, high frequency, and microwave to the electrode.
[0250]
Further, the above-described effects of the present invention have been described for the case where film formation is performed according to the present invention. However, similar effects can be obtained when performing surface treatment.
[Brief description of the drawings]
FIG. 1 is an overall conceptual diagram of an apparatus of the present invention.
FIG. 2 is a sectional view of an electrode floating type high-voltage floating electrode H1.
FIG. 3 is a lower oblique view showing a sample facing portion of the electrode floating type high-voltage floating electrode H1.
FIG. 4 is a partial cross-sectional view showing a step t between a sample J and a sample table T.
FIG. 5A is a schematic cross-sectional view near a minute interval D between an electrode floating type high-pressure floating electrode H1 and a sample J, and FIG. FIG. 4 is a schematic diagram showing a pressure distribution of FIG.
FIG. 6 is a schematic diagram showing generation of a local region plasma P at an open end of a power transmission line provided at a portion of the electrode floating type high-pressure floating electrode H1 facing a sample J;
FIG. 7A is a cross-sectional view schematically showing a configuration in the vicinity of a high-pressure reaction gas supply port 2, and FIG. 7B is a sectional view of the high-pressure reaction gas supply port 2 utilizing the configuration of FIG. FIG. 4 is a cross-sectional view showing a film thickness distribution formed immediately below the supply port 2 when a local high-pressure plasma P is generated in the vicinity of the gas flow, and FIG. It is a figure which shows typically.
FIG. 8A is a schematic view showing a configuration near the high-pressure reaction gas supply port 2 and the line open end 7 when the power transmission line open end 7 is installed at a position away from the high-pressure reaction gas supply port 2; (B) is formed immediately below the supply port 2 when the local high-pressure plasma P is generated in the vicinity including the high-pressure reaction gas supply port 2 using the configuration of (a). It is sectional drawing which shows a film thickness distribution, and (c) is a figure which shows typically the state of the gas flow which generate | occur | produces in the minute gap D at the time of the above.
FIG. 9 is a cross-sectional view of an electrode floating type high-voltage floating electrode using a highly accurate flattened corrosion-resistant and high-hardness insulator for a sample facing portion.
FIG. 10 is a sectional view of an electrode floating type high pressure floating electrode using a porous material for a high pressure reaction gas supply port.
FIG. 11 is a sectional view of an electrode floating type high pressure floating electrode in which a high pressure reaction gas supply port is installed on a sample stage T.
FIG. 12 is a schematic diagram showing a batch process using a sample stage T11 for fixing a large number of samples having multiple rotation axes and rotation speeds.
FIG. 13 is a schematic sectional view of a sample floating type high-voltage floating electrode H2.
FIG. 14 is a sectional view of a sample levitation type high pressure levitation electrode H2 in which a high pressure reaction gas supply port is provided on the sample stage T.
FIG. 15 is a schematic sectional view of a sample floating type high-voltage floating electrode H2 in which only a sample is floated.
FIG. 16 is a sectional view of an electrode floating type high-voltage floating electrode H3 using a waveguide as a power transmission line.
FIG. 17 is a partial cross-sectional view of an electrode floating type high-voltage floating electrode H3 using a waveguide as a power transmission line when viewed from another direction.
FIG. 18A is a lower oblique view of an electrode floating type high-voltage floating electrode H3 using a waveguide as a power transmission line.
FIG. 18B is a top oblique view of an electrode floating type high-voltage floating electrode H3 using a waveguide as a power transmission line.
FIG. 19A is a conceptual diagram showing the amplitude of vibration of a charged particle due to an oscillating electric field, and FIG. 19B is a schematic diagram showing an oscillating electric field that causes the vibration of FIG.
FIG. 20A is a cross-sectional view of a sample floating high-voltage floating electrode H4 using a waveguide as a power transmission line.
FIG. 20B is a front view of a sample floating high-voltage floating electrode H4 using a waveguide as a power transmission line.
FIG. 20C is a top view of a sample floating type high-voltage floating electrode H4 using a waveguide as a power transmission line.
FIG. 21 is a partial cross-sectional view of a high-voltage floating electrode H5 that performs surface smoothing and shape film formation on a sample having a spherical sample finish shape.
FIG. 22 is a schematic view showing the formation of a gas flow field by a disc H0.
23 is a diagram in which a cylindrical coordinate axis is set between a disk and a sample on which a film is to be formed in the configuration of FIG. 22;
FIG. 24 is a cross-sectional view schematically showing a configuration of a surface treatment apparatus using plasma according to a conventional technique.
FIG. 25 is a diagram schematically showing a film thickness distribution of a thin film which is considered to be formed immediately below a source gas supply port.
[Explanation of symbols]
A Floating sample
B Sample with a spherical surface
C reaction vessel
D minute interval
E exhaust system
F Sample fixing part
G power supply
G11 Microwave power supply
H0 disk
H1 electrode floating type high voltage floating electrode
H2 sample floating type high pressure floating electrode
Electrode levitation type high voltage levitation electrode using H3 waveguide for power transmission line
Sample floating type high voltage floating electrode using H4 waveguide as power transmission line
H5 High-voltage floating electrode with spherical shape on the sample facing part
I Flexible power transmission line
J sample
K power transmission line
L Vibration amplitude of charged particles due to oscillating electric field
M resonance / matching device
N control device
R High pressure reaction gas supply device
S scanning stage
T sample table
T11 Sample stage for fixing many samples
T12 Concave sample stage
T13 Spherical sample holder
U electrode scanning device
Y Floating sample scanning wire
Y11 Floating sample restraint scanning mechanism
θ Rotation mechanism of sample stage T
Rotation mechanism of the sample stage T11 for fixing a large number of samples
1 High pressure reaction gas supply path
111 Buffer section
2 High pressure reaction gas supply port
3 Reaction product exhaust path
4 Reactive gas exhaust port
5 inner electrode
6. Outer electrode
7 Open end of power transmission line
8 Connector
9 Scanning wire (belt)
10 Drive motor
11 Insulator
12. Electrode levitation type High pressure levitation electrode H1 sample facing part
1611 High-pressure reactant gas ejected from high-pressure reactant gas supply port 2
1612 High-pressure reactant gas flow that has flowed along the sample surface during minute interval D
1613 Velocity distribution of turbulent reactant gas near supply port 2
1614 Velocity distribution of reactant gas changing to shear flow away from supply port 2
1615 Flow velocity distribution of reactant gas which has become a shear flow far enough from supply port 2
1711 Distribution of film formation amount formed immediately below supply port 2 when local high-pressure plasma P is generated in the vicinity including high-pressure reaction gas supply port 2
1712 Distribution of film formation amount formed immediately below local high-pressure plasma P when power transmission line open end 7 is installed at a position distant from high-pressure reaction gas supply port 2 to generate local high-pressure plasma P
18 High precision flattening corrosion resistant and high hardness insulator
19. Porous metal or porous insulator material
20 High pressure reaction gas supply slit
21 Flexible waveguide
22 Waveguide in electrode
23 Insulator
24 Waveguide open end
25 High-pressure gas supply port
26 High-pressure gas supply path
27 Flow along the surface of the sample
28 Electrode levitation type using a waveguide as a power transmission line Electrode facing part of high pressure levitation electrode H3
29 charged particles
30 Floating sample feed belt with projection
31 Feed belt protrusion
32 Floating sample feed motor
60 Electrode facing surface of sample stage T13 for fixing spherical sample
61 Sample facing part of high-voltage floating electrode H5
62 Side view of high-voltage floating electrode H3
63 Side surface of inner concave portion of concave sample stage T12
101 High-pressure gas supply path
240p high pressure plasma
240g distance between boards
241 Deposition chamber
242 ungrounded board
243 ground electrode
244 perforated plate high resistance
245 sample substrate
246 Gas inlet
247 RF electrode
248 heater
249 Gas outlet
250 gas supply port
251 Flow of source gas impinging on the sample substrate
252 thin film
253 Projection of thin film formed just below source gas supply port

Claims (12)

A sample table that is arranged in a predetermined gas atmosphere and on which a sample to be surface-treated is placed,
An electrode provided with a wall surface at least partially having a shape similar to the shape of the surface to be processed of the sample facing the surface to be processed of the sample,
A reaction gas supply port provided on a wall surface of the electrode so as to locally supply a reaction gas to a surface to be processed of the sample,
A power source for applying power to the electrode;
A power transmission line provided in the electrode so as to transmit an electric power applied to the electrode to the open end, the power transmission line having an open end at a position away from the reaction gas supply port on the wall surface;
A wall surface of the electrode is provided close to the surface to be processed of the sample, and a gas flow path having a low conductance from the reaction gas supply port toward the gas atmosphere between the electrode and the surface to be processed of the sample. And a high-pressure reaction gas region having a pressure higher than the gas atmosphere due to a differential pressure between the pressure of the gas atmosphere and the pressure of the reaction gas supplied from the reaction gas supply port. Formed locally near the open end at
A high electric field is generated by the electric power transmitted to the open end, and a local high-pressure plasma based on the reaction gas is generated in the high-pressure reaction gas region. surface treatment on the sample is performed, the surface treatment apparatus of the sample using the plasma. An electrode provided with a wall surface at least partially having a shape similar to the shape of the surface to be processed of the sample placed in the predetermined gas atmosphere, and provided to face the surface to be processed of the sample,
A reaction gas supply port provided on a wall surface of the electrode so as to locally supply a reaction gas to a surface to be processed of the sample,
A power supply for applying power to the electrode,
At least one of the sample and the electrode is configured such that a surface to be processed of the sample and the wall surface are separated from each other by a minute gap due to a pressure difference between a pressure of the gas atmosphere and a pressure of a reaction gas supplied from the reaction gas supply port. The gas flow path having a low conductance is formed from the reactant gas supply port toward the gas atmosphere by the minute intervals, and the gas pressure is higher than the gas atmosphere by the differential pressure. A high-pressure reaction gas region having a high pressure is locally formed at a position away from the reaction gas supply port in the low conductance gas flow path,
By applying power to the electrode and generating a local high-pressure plasma based on the reaction gas in the high-pressure reaction gas region, the surface treatment of the sample is performed by a reactive species of the reaction gas in the high-pressure plasma. , Surface treatment equipment for samples using plasma. The surface treatment apparatus according to claim 2 , wherein the sample is placed on a sample stage. The pressure p0 of the gaseous atmosphere, the ratio between the pressure px of occurrence place of the high-pressure plasma in the high pressure reaction gas region, further comprising means for setting the px / p0> 1, the surface according to claim 1 or 2 Processing equipment. Wall of the electrode, Ru oppose each other across a small gap against the target surface of the sample, the surface treatment apparatus according to claim 1. 2. The surface according to claim 1 , wherein at least one of the electrode and the sample stage is configured to be movable by the differential pressure so as to float with a small gap from the other of the electrode and the sample stage . 3. Processing equipment. The electrode and at least one of the sample stage, have a magnetic force generating mechanism is provided for generating a predetermined magnitude of magnetic force,
7. The method according to claim 3 , wherein one of the electrode and the sample stage is floated with a small gap from the other by using both the magnetic force generated from the magnetic force generating mechanism and the differential pressure . Surface treatment equipment. Inside the electrode, a power transmission line having an open end at a position away from the reaction gas supply port on the wall surface of the electrode is provided,
The power transmission line, and transmit the power applied to the electrode to the open end, the transmitted power causes generating a high electric field in the vicinity of the open end, a surface treatment apparatus according to claim 2. The power transmission line includes an inner conductor power is applied, via an insulator are thus configured and the electric field shielding conductors being and grounded cover the inner conductor, the surface according to claim 1 or 8 Processing equipment. 3. The surface treatment apparatus according to claim 1 , wherein the power applied to the electrode is high-frequency power in a frequency band of 10 MHz to 1 GHz or microwave power in a frequency band of 1 GHz or more. 4. The surface treatment device according to claim 1 , wherein the power transmission line is configured by a waveguide . At least one of the electrode and the sample stage is provided with a power absorber having a large absorption coefficient for electromagnetic waves having a frequency of a power supply to be used,
The power absorber is disposed on a lower pressure side of the high-pressure plasma generation region in the low-conductance gas flow path, absorbs an electromagnetic wave passing through the high-pressure plasma generation region, and surrounds the high-pressure plasma around the high-pressure plasma. The surface treatment apparatus according to claim 1 , wherein generation of plasma in the gaseous atmosphere is suppressed.

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