JP3682689B2 - Film forming method and apparatus - Google Patents

Description

の反応を生ずる。
【００２６】
上記のようにして放電ユニット１２において生成された反応性フッ素系ガスは、酸素供給管３２を介してガス混合部５２に流入する酸素ガス（Ｏ₂ ）、オゾン（Ｏ₃ ）と混合し、これらを次のように分解する。
【化２】

【化３】

【００２７】
このようにして生じた活性種である酸素原子（Ｏ）は、希釈ガスのアルゴンや他のガス成分とともに処理室６０に、成膜用ガスとして大気圧状態で供給される。この成膜用ガスは、処理ステージ６４上のシリコンウエハ６２と接触し、活性な酸素が、
【化４】

の反応によってシリコンを酸化し、シリコンウエハ６２の表面にシリコン酸化膜（ＳｉＯ₂ 膜）を形成する。また、この際、ラジカルな酸素原子とともに処理室６０に流入したＨＦは、シリコンウエハ６２の表面に存在する水素、フッ素などと結合した自然形成膜と反応してこれらを除去する。
【００２８】
すなわち、ＨＦは、シリコンウエハ６２の表面に存在する［Ｓｉ_X 、Ｓｉ_Y 、Ｓｉ（ＯＨ）_Z ］からなる膜と、
【化５】

のように反応し、シリコンウエハ６２の表面に存在する好ましくない自然形成膜を除去する。このため、活性な酸素と反応して形成されたシリコン酸化膜は、自然形成膜が除去されているために絶縁性能の高い良質の絶縁膜となる。
【００２９】
しかも、実施の形態においては、反応性ハロゲン系ガスである反応性のフッ素系ガスと、原料ガスである酸素、オゾンとを、シリコンウエハ６２を配置した処理室６０に供給する前に、ガス混合部５２において混合させているため、両者が充分に混合されて原料ガスの分解が促進され、処理室６０に供給される原料ガスの活性種であるラジカルな酸素の量が増大し、成膜速度を高めることができる。そして、実施の形態においては、大気圧下における成膜をすることができ、真空を形成する必要がないために設備費やランニングコストを削減することができ、環境負荷を低減することができる。また、実施の形態においては、従来の熱酸化に比較して非常に低い温度で成膜が可能であって、設備の簡素化とエネルギーの低減を図ることができる。さらに、実施形態においては、反応性の乏しい安定なＣＦ₄ を用いて放電ユニット１２において反応性のフッ素系ガスを得るようにしているため、取扱いが容易で作業の安全性を高めることができる。しかも、放電ユニット１２において生成した反応性フッ素系ガスを、放電ユニット１２とは異なる処理室６０に輸送して成膜しているため、シリコンウエハ６２に放電による損傷を与えるおそれがない。さらに、処理室６０を加熱しているため、処理室６０に導入された水分は、処理室６０内の反応によって生じた水分が結露するのを防止することができ、成膜を安定して行なえ、良質のシリコン酸化膜が得られる。
【００３０】
《シリコン酸窒化膜の形成》
前記シリコン酸化膜の形成の場合と同様に、洗浄したシリコンウエハ６２を処理ステージ６４の上に配置し、所定の温度に保持する。そして、安定ハロゲン供給部１８から放電ユニット１２にＣＦ₄ を供給する。このＣＦ₄ の一部は、前記と同様に第１水バブリングユニット２２を介して供給し、放電ユニット１２において反応性フッ素系ガスを生成する。また、窒素供給管３０を介して窒素ガス供給源３８から原料ガスである窒素ガスをハロゲン供給管２８に供給する。ただし、窒素ガス供給源３８からの窒素ガスの一部は、第２水バブリングユニット４４を通過させ、水分を添加してハロゲン供給管２８に流入させる。さらに、シリコン酸化膜の形成の場合と同様に、酸素ガス供給源４８からの原料ガスとなる酸素ガスをオゾン発生器５０に供給して一部をオゾンにしたのち、ハロゲン供給管２８のガス混合部５２に供給する。また、アルゴンガス供給源５６からアルゴンガスを希釈ガスとしてハロゲン供給管２８に供給する。
【００３１】
放電ユニット１２において生成された反応性フッ素系ガスは、ガス混合部５２において酸素やオゾンと次のような反応をする。
【化６】

【化７】

さらに、このようにして生成されたＦ₂ が水分を含んだ窒素ガスと、
【化８】

のように反応して活性なＮＯが生成される。このＮＯは、活性な酸素（Ｏ）とともに処理室６０に流入し、
【化９】

のようにシリコンと反応してシリコン酸窒化膜を形成する。このとき、前記と同様に処理室６０に供給されたＨＦがシリコンウエハ６２の表面に存在する自然形成膜と反応してこれを除去する。したがって、前記シリコン酸化膜の形成と同様の効果を得ることができる。
【００３２】
《シリコン窒化膜の形成》
前記と同様にしてシリコンウエハ６２を処理ステージ６４の上に配置する。そして、放電ユニット１２にＣＦ₄ と水（水分）とを供給して反応性フッ素系ガスを生成する。また、ハロゲン供給管２８への酸素ガス、オゾンの供給を行なわず、窒素ガスとアルゴンガスのみを供給する。なお、窒素ガスは、第２水バブリングユニット４４を通さず、ハロゲン供給管２８に水分を供給しないようにする。これにより、化学式１に示したＨＦとＣＯ₂ とが窒素ガスと次のように反応し、活性種である窒素単原子が生成される。
【化１０】

さらに、窒素単原子が、
【化１１】

のように反応し、シリコン窒化膜が形成される。この場合においても、前記と同様の効果が得られる。
【００３３】
なお、前記実施の形態においては、ワークがシリコンウエハ６２である場合について説明したが、ワークは多結晶シリコンやアモルファスシリコン、ゲルマニウムなどの半導体であってもよく、さらにアルミニウムや銅、タンタルなどの各種金属、各種セラミックなどの絶縁体であってもよい。そして、前記実施形態においては、シリコンウエハ６２に絶縁膜を形成する場合について説明したが、例えばＩＴＯ（Ｉｎｄｉｕｍ Ｔｉｎ Ｏｘｉｄｅ）などの製作や磁性体薄膜などの各種デバイス薄膜の製作に適用することができる。また、前記実施形態においては、シリコンウエハ６２を処理室６０内に配置して成膜する場合について説明したが、シリコンウエハ６２を処理室外の開放系に配置して成膜処理を行なってもよい。さらに、前記実施形態においては、ハロゲン系ガスがフッ素系ガスである場合について説明したが、ワークの材質によっては塩素系ガスや臭素系ガスなどの他のハロゲン系ガスを用いることができる。
【００３４】
図３は、ガス混合部の他の実施形態を示したものである。この実施形態に係るガス混合部１００は、攪拌手段が設けてある。すなわち、ガス混合部１００は、混合室１０６の内部にモータ１０２によって回転駆動されるファン１０４が配設してあり、混合室１０６に流入したガスを攪拌できるようにしてある。このようになっているガス混合部１００においては、反応性フッ素系ガスと原料ガス（窒素ガスまたは／および酸素ガス、オゾン）との混合をより迅速、充分に行なうことができ、原料ガスの活性種をさらに多くすることができる。
【００３５】
図４は、他の実施形態の要部を示したものである。図４に示した成膜装置１１０は、ハロゲン供給管２８のアルゴン供給管３４との接続部１１２より下流側に、ブロアや圧縮機などの昇圧手段１１４が設けてあって、処理室６０に供給する成膜用の処理ガスを昇圧できるようにしてある。また、処理室６０に接続した排気管６８には、圧力制御弁１１６が設けてあって、処理室６０内の圧力を所定の値に保持できるようになっている。さらに、処理室６０には、圧力センサ１１８が設けてあって、処理室６０内の圧力を検出できるようにしてある。この圧力センサ１１８の出力信号は、昇圧手段１１４を駆動するモータ１２０を制御するコントローラ１２２に入力するようになっている。このコントローラ１２２は、圧力センサ１１８が出力する検出信号に基づいて、処理室６０内の圧力が設定値となるようにモータ１２０を介して昇圧手段１１４を駆動する。
【００３６】
このように構成した実施形態に係る成膜装置１１０は、処理室６０の内部を大気圧より高い圧力にすることができ、処理室６０に供給される成膜用処理ガスの活性種の量を多くすることが可能で、成膜速度をより高めることができる。
【００３７】
【実施例】
図１に示した成膜装置１０と同様の装置を用いて成膜実験を行なった。成膜実験に使用した処理室６０は、アルミニウムによって円筒状に形成した容積が８０ｍＬである。そして、処理室６０内に配置したワークは、一辺が２０ｍｍの単結晶シリコン（試料）を用いた。また、放電ユニット１２は、図２に示した放電部８０の長さＬが４０ｍｍ、放電部８０の幅Ｄが７０ｍｍであって、上下の電極８２、８４の電極歯８８、９０の厚さｔが１ｍｍ、高さｈが３ｍｍであって、図２（２）の紙面に直交した方向の長さが４０ｍｍである。さらに、ガス流路９２、９４は幅が３ｍｍ、高さが３ｍｍの断面正方形である。また、絶縁板８６は、アルミナ（Ａｌ₂ Ｏ₃ ）によって形成してあり、厚さｄが１ｍｍである。そして、上部電極８２と下部電極８４との間に印加した電圧は、周波数が１５〜２０ｋＨｚであり、電圧値がｐ−ｐ値で１０ｋＶである。
【００３８】
処理室６０は、試料を配置したのち、図５に示したように、室温から２００℃まで内部を昇温した。昇温速度は３５〜４０℃／ｍｉｎである。そして、処理室６０の内部が２００℃に達した段階で、処理室内に乾燥した窒素ガスを１０Ｌ／ｍｉｎの割合で１０分間供給し、窒素ガスによる置換を行なった。その後、窒素ガスの供給を停止し、後述する成膜用の処理ガスを９０分間供給し、試料の表面に酸化膜、酸窒化膜、窒化膜を成膜した。そして、９０分間の成膜試験が終了した段階で、再び窒素ガスを１０Ｌ／ｍｉｎの割合で処理室６０に供給し、室温まで放冷しながら窒素ガスによる置換を１０分間行なった。なお、放電ユニット１２における放電と、処理室６０における成膜処理は、いずれも大気圧状態で行なっている。そして、これらの条件は、下記の各実施例について適用した。
【００３９】
《実施例１》
上記のようにして処理室６０の内部を窒素ガスによる置換を行なったのち、放電ユニット１２に１００ｍＬ／ｍｉｎのＣＦ₄ を供給した。ただし、半分の５０ｍＬ／ｍｉｎは、第１水バブリングユニット２２に導入し、水分を含ませて放電ユニット１２に供給した。また、酸素ガス供給源４８から２００ｍＬ／ｍｉｎの酸素ガスをオゾン発生器５０に供給し、酸素ガスの一部をオゾンにしてハロゲン供給管２８のガス混合部５２に供給した。したがって、供給された酸素およびオゾンとＦ₄ との比は、（Ｏ₂ ／Ｏ₃ ）：ＣＦ₄ ＝２：１である。
【００４０】
ただし、窒素ガス供給源３８からハロゲン供給管２８に窒素ガスの供給は行なわなかった。なお、オゾン発生器５０によるオゾンの生成割合は、１００％の酸素ガスである場合、２．３体積％であった。
【００４１】
このような条件で生成した成膜用ガスを処理室６０に供給し、試料の成膜処理を９０分間行なったところ、試料の表面にシリコン酸化膜が形成された。そして、このシリコン酸化膜を分析したところ、ウエット洗浄に伴う水素やフッ素を含んだ自然形成膜が除去されていて、非常に高品質のシリコン酸化膜を形成することができた。
【００４２】
《実施例２》
実施例１と同様に、酸素ガス供給源４８から酸素ガスを、オゾン発生器５０を介してハロゲン供給管２８に設けた混合部５２に２００ｍＬ／ｍｉｎ供給するとともに、安定ハロゲン供給部１８からＣＦ₄ を放電ユニット１２に５０ｍＬ／ｍｉｎ供給し、窒素ガス供給源３８から窒素ガスをハロゲン供給管２８に５０ｍＬ／ｍｉｎ供給した。したがって、各ガスの流量割合は、（Ｏ₂ ／Ｏ₃ ）：Ｎ₂ ：ＣＦ₄ ＝４：１：１である。ただし、ＣＦ₄ と窒素ガスとは、供給量の半分の２５ｍＬ／ｍｉｎが水バブリングユニットを通さないドライなガスであり、残り半分の２５ｍＬ／ｍｉｎが第１水バブリングユニット２２または第２水バブリングユニット４４に通して水分を含ませたウエットなガスである。
【００４３】
上記のようにして生成した成膜用処理ガスを処理室６０に供給して９０分の成膜処理を行なったところ、単結晶シリコンからなる試料の表面にシリコン（Ｓｉ）、酸素（Ｏ）、窒素（Ｎ）からなるシリコン酸窒化膜を形成することができた。この場合においても、洗浄の影響による自然形成膜が除去され、絶縁特性に優れた絶縁膜を得ることができた。
【００４４】
《実施例３》
安定ハロゲン供給部１８から放電ユニット１２に安定なフッ素系ガスであるＣＦ₄ を供給し、放電によって反応性フッ素系ガスを生成した。放電ユニット１２に供給したＣＦ₄ は、水分を含ませないドライなガスが５０ｍＬ／ｍｉｎ、第１水バブリングユニット２２を通した水分を含ませたウエットなガスが５０ｍＬ／ｍｉｎである。また、窒素ガス供給源３８から２００ｍＬ／ｍｉｎの第２水バブリングユニット４４を通さないドライな窒素ガスをハロゲン供給管２８に供給した。したがって、原料ガスである窒素ガスとＣＦ₄ との比は、Ｎ₂：ＣＦ₄＝２：１である。
【００４５】
このようなガスによって生成した成膜用ガスを処理室６０に供給して成膜処理を９０分間行なったところ、単結晶シリコンからなる試料の表面にシリコン（Ｓｉ）と窒素（Ｎ）とからなるシリコン窒化膜が形成された。また、このようにして行なった成膜は、前記の実施例と同様に試料表面の自然形成膜が除去されており、成膜されたシリコン窒化膜が優れた絶縁性を示した。
【００４６】
《実施例４》
図６は、成膜用処理ガスの種類と成膜速度との関係を示したものである。なお、使用した装置および温度条件、試料などは前記各実施例と同様であって、成膜用ガスだけが異なっている。
【００４７】
図６の下部にＡｒとして示したものは、酸素ガス供給源４８からの酸素ガスを、オゾン発生器５０を介してガス混合部に２００ｍＬ／ｍｉｎ供給し、アルゴンガス供給源５６から１００ｍＬ／ｍｉｎのアルゴンガスをハロゲン供給管２８に供給し、これらの混合ガスを処理室６０に導入して成膜処理を行なった結果である。ただし、安定ハロゲン供給部１８からのＣＦ₄ の供給と、窒素ガス供給源３８からの窒素ガスの供給とは行なっていない。この場合、９０分の成膜処理を行なったが、測定の誤差の範囲であって成膜は行なわれなかった。
【００４８】
図６にＮ₂ として示したものは、酸素ガスおよびオゾンと窒素ガスとによる成膜処理の結果を示したものである。すなわち、窒素ガス供給源３８から１００ｍＬ／ｍｉｎの窒素ガスをハロゲン供給管に供給し、酸素ガス供給源４８からオゾン発生器５０を介して２００ｍＬ／ｍｉｎの酸素ガスをハロゲン供給管２８に供給し、ガス混合部５２で混合したのち、処理室６０に導入した。ただし、窒素ガスは、第２水バブリングユニット４４を介してウエットの状態で供給した。この場合、９０分の成膜処理を行なったが、ほとんど測定の誤差の範囲であって、約０．１オングストローム／分（ｍｉｎ）の成膜速度が得られた。
【００４９】
図６にＣＦ₄ （ＤＲＹ）として示したものは、安定ハロゲン供給部１８から放電ユニット１２に乾燥したＣＦ₄ を１００ｍＬ／ｍｉｎ供給し、放電ユニット１２における気体放電によりＦ₂ などの反応性フッ素系ガスを生成するとともに、酸素ガス供給源４８から２００ｍＬ／ｍｉｎの酸素ガスを、オゾン発生器５０を介してハロゲン供給管２８に供給し、これらの混合ガスを成膜用ガスとして処理室６０に供給し、９０分間の成膜処理をしたときの結果である。この場合においても、図から明らかなように、ほぼ測定の誤差範囲内であって、約０．２オングストローム／分の成膜速度であった。
【００５０】
図６にＮ₂ ＋ＣＦ₂ （Ｈ₂ Ｏ）と記載したものは、放電ユニット１２に、第１水バブリングユニット２２を介したウエットなＣＦ₄ を５０ｍＬ／ｍｉｎ供給し、放電によって反応性フッ素系ガスを生成するとともに、窒素ガス供給源３８から第２水バブリングユニット４４を介したウエットな窒素ガスを５０ｍＬ／ｍｉｎハロゲン供給管２８に供給し、さらに酸素ガス供給源４８から２００ｍＬ／ｍｉｎの酸素ガスをオゾン発生器５０に供給し、酸素ガスとオゾンとの混合ガスにしてガス混合部５２に流入させ、これらの混合ガスによる成膜用ガスを処理室６０に導入し、９０分間の成膜処理を行なった結果を示したものである。この場合、シリコン酸窒化膜が形成され、成膜速度が大幅に上昇して約１．４５オングストローム／分の成膜速度を得ることができた。ただし、希釈ガスであるアルゴンを供給していない。
【００５１】
図６にＣＦ₄ （Ｈ₂ Ｏ）として示したものは、放電ユニット１２に、第１水バブリングユニット２２を通過させたウエットなＣＦ₄ を１００ｍＬ／ｍｉｎ供給して反応性フッ素系ガスを生成するとともに、酸素ガス供給減４８からの酸素ガス２００ｍＬ／ｍｉｎを、オゾン発生器５０を介して酸素ガスとおよびオゾンの混合ガスにし、ハロゲン供給管２８に供給して得た成膜用ガスを処理室６０に導入し、９０分間の成膜処理を行なった結果である。なお、窒素ガスとアルゴンガスとは、成膜用ガスに添加していない。この場合、シリコンからなる試料の表面にシリコン酸化膜が形成された。また、シリコン酸化膜の成膜速度は、約１．６オングストローム／分であった。
【００５２】
【発明の効果】
以上に説明したように、本発明によれば、ワークと反応させてワークの表面に膜を形成する原料ガスに反応性ハロゲン系ガスを添加したことにより、原料ガスが反応性ハロゲンガスによって活性化されるとともに、ワークの表面に存在するウエット洗浄時の残存物である水素やフッ素と結合した膜が反応性ハロゲン系ガスによって除去されるため、これらの自然に形成された膜の除去と、原料ガスの反応による成膜とを同時に行なうことができ、品質の優れた膜を形成することができる。
【図面の簡単な説明】
【図１】本発明の実施の形態に係る成膜装置の説明図である。
【図２】実施の形態に係る放電ユニットの詳細説明図である。
【図３】他の実施形態に係るガス混合部の説明図である。
【図４】他の実施の形態に係る成膜装置の要部説明図である。
【図５】実施例における温度プロファイルの説明図である。
【図６】実施例における成膜用ガスと成膜速度との関係を示す図である。
【符号の説明】
１０、１１０………成膜装置、１２………放電部（放電ユニット）、
１８………ハロゲン系ガス供給部（安定ハロゲン供給部）、
２２………水分供給手段（第１水バブリングユニット）、
３６………原料ガス供給部、３８………窒素ガス供給源、
４４………第２水分供給手段（第２水バブリングユニット）、
４８………酸素ガス供給源、５０………オゾン発生器、
５２、１００………ガス混合部、６０………処理室、
６２………ワーク（シリコンウエハ）、６６………加熱手段（加熱器）、
１０４………攪拌手段（ファン）、１１４………昇圧手段、
１１６………圧力制御弁、１１８………圧力センサ、
１２０………モータ、１２２………コントローラ。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method of forming a film on the surface of a workpiece by reacting the workpiece with a gas, and particularly suitable for forming an insulating film such as a silicon oxide film or a silicon nitride film on the surface of a silicon wafer or the like. The present invention relates to a membrane method and apparatus.
[0002]
[Prior art]
  In the case of forming a semiconductor device using a silicon wafer, an insulating film such as a silicon oxide film or a silicon nitride film is used to separate the elements from each other and to insulate the elements from the wiring layer. When forming a silicon oxide film or a silicon nitride film, a silicon wafer is placed in an oxidizing atmosphere in which oxygen exists, or in a nitriding atmosphere such as nitrogen gas or ammonia,AtmosphereThere is a method in which silicon and oxygen or silicon and nitrogen are directly reacted while being held at a high temperature. Japanese Patent Application Laid-Open No. 62-99463 discloses that silane gas, fluorine gas, oxygen gas and / or dinitrogen tetroxide gas are introduced into a vacuum chamber having a reduced pressure, and silicon is placed on the surface of a workpiece placed in the vacuum chamber. , Oxygen or / and a method of depositing an insulating film made of nitrogen, hydrogen, and fluorine.
[0003]
[Problems to be solved by the invention]
In the method for forming an insulating film described in the above publication, a silane gas as a raw material gas, a fluorine gas as an oxidant, and an oxygen gas or / nitrous tetroxide gas are simultaneously introduced into a vacuum chamber by a triple gas introduction pipe. I am trying to supply. For this reason, each gas introduced into the vacuum chamber comes into contact with the workpiece without being sufficiently mixed, reacts with the workpiece before some of the gases are activated, and is unnecessary or undesirable for the deposition of the insulating film. A component is generated, and this component may be taken into the insulating film, which may deteriorate the film quality. Also, since each gas comes into contact with the workpiece in a state where it is not sufficiently mixed, a part of the gas is not activated, so the amount of active species is small compared to the amount of gas introduced into the vacuum chamber, and the film formation efficiency As a result, gas use efficiency decreases. Furthermore, the film forming method described in the above publication uses a high-pressure silane gas as a raw material gas while reacting in a vacuum state, which increases equipment costs and running costs, and increases the film forming costs.
[0004]
  On the other hand, when an insulating film or the like is formed on a silicon wafer, the natural oxide film present on the surface of the silicon wafer is generally removed with a cleaning liquid mainly composed of hydrofluoric acid before the film forming process. However, in the process of drying the cleaned silicon wafer, a natural oxide film is formed again,In the cleaning solutionExisting hydrogen and fluorine remain on the surface of the silicon wafer. For this reason, even if an insulating film is deposited on the cleaned silicon wafer as described in the above publication, a natural oxide film, hydrogen, fluorine, etc. exist below the formed insulating film, Combined with hydrogen or fluorineInsulationA film with insufficient characteristics may be formed naturally, which may deteriorate the characteristics of the formed insulating film.
[0005]
The present invention has been made in order to eliminate the above-mentioned drawbacks of the prior art, and an object of the present invention is to allow film formation while removing undesired films formed naturally.
Another object of the present invention is to increase the amount of active species of the raw material gas to be reacted with the workpiece.
Furthermore, an object of the present invention is to form a film having excellent characteristics.
[0006]
[Means for Solving the Problems]
  In order to achieve the above object, a film forming method according to the present invention is a method of forming a film on the surface of a workpiece by reacting a workpiece with an active species of a source gas.Stable halogen system containing moisture at atmospheric pressureA gas is activated to generate a reactive halogen-based gas, and the source gas is added to the generated reactive halogen-based gas.Added and mixed to generate active species of the source gas, containing the active speciesA mixed gas is brought into contact with the workpiece.
[0007]
In the present invention configured as described above, when a reactive halogen-based gas such as fluorine gas or hydrogen fluoride gas is added to the raw material gas, the reactive halogen gas reacts with the raw material gas, and the raw material gas is decomposed and activated. The reactive halogen gas reacts with the naturally formed film (naturally formed film) combined with hydrogen, fluorine, etc. remaining on the surface of the work after cleaning, and removes the naturally formed film. To do. For this reason, the film formation by the active species of the source gas and the removal of the naturally formed film proceed at the same time, and the film formed on the surface of the workpiece does not have an undesired naturally formed film below it, and thus has excellent characteristics. Can be.
[0008]
When the active species of the raw material gas is brought into contact with the workpiece, a mixed gas of the raw material gas and the reactive halogen-based gas is generated before being brought into contact with the workpiece, and this mixed gas is preferably brought into contact with the workpiece. When a mixed gas of a source gas and a reactive halogen gas is generated and then brought into contact with the workpiece, the gas is sufficiently mixed before contacting the workpiece and the amount of active species in the source gas increases, resulting in a film formation rate. Can be increased. Further, when the workpiece is heated and brought into contact with the active species of the source gas, the reaction between the workpiece and the active species is promoted, and the film formation rate can be increased.
[0009]
  And CF₄Or C₂F₆When a reactive halogen-based gas is generated by gas discharge of a stable (non-reactive) halogen-based gas as described above, handling is easy and safety can be improved. Gas discharge uses a stable halogen-based gas.At atmospheric pressureIt is good to hold it. in this wayAt atmospheric pressureGenerating reactive halogen gases by discharge (so-called atmospheric pressure discharge) eliminates the need for expensive vacuum chambers and vacuum pumps, which reduces equipment costs and eliminates the need for a vacuum, saving energy. Since it can be done, the environmental load can be reduced and the running cost can be reduced. In addition, a stable halogen-based gas may contain moisture. When a stable halogen-based gas is discharged in a moisture-containing state, the stable halogen-based gas reacts with water to cause F or F₂, HF, COF₂The reactive halogen gas can be efficiently generated.
[0010]
When the workpiece is silicon such as a silicon wafer, if the source gas is oxygen or ozone, or a mixture of both, oxygen and ozone are decomposed by the reactive halogen-based gas, and the active oxygen atoms react with silicon. In addition, a high-quality silicon oxide film having excellent insulating properties can be formed on the surface of silicon. In addition, unlike thermal oxidation of silicon and the like, film formation can be performed at a relatively low temperature, so that the film formation energy can be reduced and the cost can be reduced.
[0011]
In addition, when the workpiece is silicon such as a silicon wafer and the source gas is nitrogen, the nitrogen gas is decomposed by the reactive halogen-based gas, and the nitrogen atoms as the active species react with the silicon to insulate the silicon surface. A high-quality silicon nitride film having excellent properties can be formed. Also in this case, the silicon nitride film can be formed without holding the workpiece at a high temperature as in thermal nitridation, and energy can be reduced. When the workpiece is silicon and the source gas is a mixed gas of oxygen or / and ozone and nitrogen, these gases are decomposed by the reactive halogen-based gas, and active oxygen atoms and nitrogen atoms become silicon and silicon. A so-called silicon oxynitride film composed of silicon, oxygen and nitrogen can be formed by reaction. Since this silicon oxynitride film also has no naturally formed film below it, it can be a film having excellent insulating properties, and energy required for film formation can be reduced. Nitrogen may be added with moisture. When moisture is added to nitrogen, the moisture reacts with the reactive halogen-based gas to generate active oxygen, so that a so-called silicon oxynitride film can be formed.
[0012]
A mixed gas obtained by adding a reactive halogen-based gas to the source gas can be pressurized and brought into contact with the workpiece. When the pressure-increased gas is brought into contact with the workpiece in this way, the amount of active species that come into contact with the workpiece per unit time can be increased, and the film formation rate can be improved.
[0013]
  A film forming apparatus according to the present invention for carrying out the above film forming method,Contains moisture at atmospheric pressureA discharge part that generates a reactive halogen-based gas by discharge through a stable halogen-based gas, and the reactive halogen-based gas generated by the discharge part and the source gasMix to produce active species of the source gasA gas mixing unit and a work are arranged and supplied from the gas mixing unit.Mixed gas containing the active speciesAnd a processing chamber for contacting the workpiece with the workpiece.
[0014]
The processing chamber can be provided with a heating means for heating the workpiece in order to increase the reaction rate between the workpiece and the active species. In addition, when the gas mixing part is provided with a stirring means, the source gas and the reactive halogen-based gas can be mixed efficiently, the generation efficiency of active species is improved, the amount thereof is increased, and the film formation rate is increased. be able to. Then, a moisture supply means for adding moisture to the stable halogen-based gas is provided between the halogen-based gas supply unit for supplying a stable halogen-based gas to the discharge unit and the discharge unit. When the system gas is supplied to the discharge part, the generation efficiency of the reactive halogen-based gas can be improved.
[0015]
  When the second moisture supply means for adding moisture to the source gas is provided between the source gas supply unit that supplies the source gas and the gas mixing unit, for example, when the source gas does not contain oxygen such as nitrogen, Thus, a film having nitrogen and oxygen can be formed on the workpiece. In addition, a pressure increasing means is provided between the gas mixing section and the processing chamber.Provided,When the pressure of the mixed gas is increased and brought into contact with the workpiece, the amount of active species in contact with the workpiece increases, and the film formation rate can be increased.
[0016]
DETAILED DESCRIPTION OF THE INVENTION
Preferred embodiments of a film forming method and apparatus according to the present invention will be described in detail with reference to the accompanying drawings.
FIG. 1 is an explanatory diagram of a film forming apparatus according to an embodiment of the present invention. In FIG. 1, a film forming apparatus 10 includes a discharge unit 12 that is a discharge unit. A stable halogen supply unit 18 is connected to the gas inlet 14 of the discharge unit 12 via a gas supply pipe 16. The stable halogen supply unit 18 has a CF_FourOr C₂F₆A stable (non-reactive) halogen-based gas such as CF in this embodiment_Four) Is supplied to the discharge unit 12 through the gas supply pipe 16. The gas supply pipe 16 is provided with a flow rate control valve 20 so that the amount of gas supplied to the discharge unit 12 can be arbitrarily controlled.
[0017]
One end of branch pipes 24 and 26, the other ends of which are connected to the first water bubbling unit 22, are connected to the upstream side (stable halogen supply unit 18 side) and the downstream side of the flow control valve 20, so that the stable halogen CF from supply section 18_FourA part of the water can be introduced into the first water bubbling unit 22. The branch pipe 24 is provided with a flow rate control valve 27, which supplies CF to the first water bubbling unit 22._FourThe amount can be controlled.
[0018]
  The first water bubbling unit 22 is connected to the discharge unit 12 by CF.₄A water supply means for supplying water together with the CF supplied to the first water bubbling unit 22₄Can be returned to the gas supply pipe 16 via the branch pipe 26. And the discharge unit 12 is CF by gas discharge so that it may mention later.₄And moisture (H₂O) and F or F₂,HF, COF ₂ ofReactive halogen-based gas is generated and sent out to a halogen supply pipe 28 connected to the gas outlet 27.
[0019]
A nitrogen supply pipe 30, an oxygen supply pipe 32, and an argon supply pipe 34 are connected to the halogen supply pipe 28. The nitrogen supply pipe 30 is connected at the base end side to a nitrogen gas supply source 38 constituting the source gas supply unit 36, and allows nitrogen gas stored in the nitrogen gas supply source 38 to flow into the halogen supply pipe 28. . The nitrogen supply pipe 30 is connected in parallel with a second water bubbling unit 44 as a second moisture supply means via branch pipes 40 and 42 to which one ends of the nitrogen supply pipe 30 are connected. A part of the nitrogen gas from the nitrogen gas supply source 38 flows into the second water bubbling unit 44, and moisture can be added to the nitrogen gas to supply it to the halogen supply pipe 28. Further, a flow rate control valve 46 for controlling the flow rate of nitrogen gas is provided between the connecting portions of the nitrogen supply pipe 30 between the branch pipes 40 and 42. Further, the branch pipe 40 is provided with a flow rate control valve 47 so that the amount of nitrogen gas supplied to the second water bubbling unit 44 can be adjusted.
[0020]
The source gas supply unit 36 includes an oxygen gas supply source 48 along with a nitrogen gas supply source 38. The oxygen supply pipe 32 connecting the oxygen gas supply source 48 and the halogen supply pipe 28 is provided with a flow control valve 49 and an ozone generator 50, and the oxygen supply pipe 48 is connected to the oxygen supply pipe 48. The oxygen gas sent to 32 is supplied to the ozone generator 50, and a part of the oxygen gas is changed to ozone. The connecting portion between the oxygen supply pipe 32 and the halogen supply pipe 28 is a gas mixing section 52, which is a reactive halogen-based gas from the discharge unit 12, a nitrogen gas from the nitrogen gas supply source 38, and ozone. The oxygen gas and ozone that have passed through the generator 50 are sufficiently mixed. The gas mixing section 52 may have a normal piping connection structure.
[0021]
The other end of the argon supply pipe 34 is connected to an argon gas supply source 56 via a flow rate control valve 54, and argon gas as a dilution gas is supplied to the halogen supply pipe 28 on the downstream side of the gas mixing unit 52. To do. The tip of the halogen supply tube 28 is connected to a processing chamber 60 for performing a film forming process. The processing chamber 60 includes a processing stage 64 in which a silicon wafer 62 serving as a workpiece is placed. In addition, the processing chamber 60 is provided with a heater (heating means) 66 for heating the inside, so that the silicon wafer 62 can be heated to a predetermined temperature. Further, the processing chamber 60 is connected to a detoxifying device 72 and an HF scrubber 74 via an exhaust pipe 68, and harmlessly removes unused gas from the film forming processing gas supplied to the processing chamber 60. To make it possible. Note that a heater serving as a heating unit may be incorporated in the processing stage 64 so that the silicon wafer 62 is directly heated.
[0022]
As shown in FIG. 2 (1), the discharge unit 12 includes a gas distribution part 76 provided with the gas inlet 14 and a gas collecting part 78 provided with the gas outlet 27. A discharge unit 80 is provided between the gas distribution unit 76 and the gas collection unit 78. As shown in FIG. 2B, the discharge unit 80 includes an upper electrode 82 and a lower electrode 84. In the embodiment, the upper electrode 82 is connected to a high-frequency power source (not shown). The lower electrode 84 is grounded. Further, the discharge part 80 is formed between the upper electrode 82 and the lower electrode 84 with ceramic (Al₂O_ThreeAn insulating plate 86 is interposed. In the case of the embodiment, the upper electrode 82 and the lower electrode 84 are made of aluminum, and the opposing portions of the upper electrode 82 and the lower electrode 84 are formed in a comb shape having a plurality of electrode teeth 88 and 90. Further, the upper electrode 82 and the lower electrode 84 are arranged such that the electrode teeth 88 and the electrode teeth 90 are staggered, and the tips of the electrode teeth 88 and 90 are in contact with the insulating plate 86. The upper electrode 82 has a gas flow path 92 that forms a discharge space between adjacent electrode teeth 88, 88, and the lower electrode 84 has a gas flow path 94 that forms a discharge space between adjacent electrode teeth 90, 90. In the direction perpendicular to the paper surface of FIG._FourIs flowing.
[0023]
Film formation on the silicon wafer 62 by the film forming apparatus 10 according to the embodiment configured as described above is performed as follows.
<Formation of silicon oxide film>
After the silicon wafer 62 is wet washed with diluted hydrofluoric acid or the like and dried, the silicon wafer 62 is placed on the processing stage 64 of the processing chamber 60, and the inside of the processing chamber 60 is heated by the heater 66 to form the desired silicon wafer 62. Hold at membrane processing temperature. The film formation temperature may be room temperature, but heating can increase the film formation rate. In the embodiment, the heating temperature of the silicon wafer 62 is 200 to 300 degrees, but it may be higher than this.
[0024]
When a silicon oxide film is formed on the surface of the silicon wafer 62, CF, which is a stable halogen-based gas, is supplied from the stable halogen supply unit 18._FourIs supplied to the discharge unit 12 through the gas supply pipe 16 at atmospheric pressure. Further, oxygen, which is a raw material gas, is supplied from the oxygen gas supply source 48 to the gas mixing unit 52 of the halogen supply pipe 28 via the ozone generator 50 provided in the oxygen supply pipe 32. As a result, the oxygen gas partially becomes ozone that is easily decomposed, and the mixed gas of oxygen gas and ozone is supplied to the gas mixing unit 52. Further, argon as a dilution gas is supplied from the argon gas supply source 56 to the halogen supply pipe 28 via the argon supply pipe 34.
[0025]
CF supplied to the discharge unit 12_FourPart of the water is introduced into the first water bubbling unit 22 to contain moisture, and the moisture (water) is converted into CF._FourAt the same time, it is supplied to the discharge unit 12. When a predetermined high-frequency voltage is applied between the upper electrode 82 and the lower electrode 84, the discharge unit 12 has a CF that flows through the gas flow paths 92 and 94._FourDischarge occurs through a mixed gas of water and water. In the case of the embodiment, the corners of the gas flow paths 92, 94, that is, the corners on the side where the electrode teeth 88, 90 and the insulating plate 86 are in contact with each other become the discharge regions 96, 98, and CF_FourAnd moisture (H₂O) and creeping discharge occurs, and CF_FourAnd H₂React with O, HF and F₂And COF₂Reactive halogen gas (fluorine gas) is generated. F₂And COF₂Some of them further react with water to become HF. For this reason,
[Chemical 1]

The following reaction occurs.
[0026]
The reactive fluorine-based gas generated in the discharge unit 12 as described above is oxygen gas (O 2) flowing into the gas mixing unit 52 through the oxygen supply pipe 32.₂), Ozone (O_Three) And decompose them as follows.
[Chemical 2]

[Chemical 3]

[0027]
Oxygen atoms (O), which are active species generated in this way, are supplied to the processing chamber 60 together with the dilution gas argon and other gas components as a film forming gas at atmospheric pressure. This film-forming gas comes into contact with the silicon wafer 62 on the processing stage 64, and active oxygen is
[Formula 4]

As a result of this reaction, silicon is oxidized and a silicon oxide film (SiO 2) is formed on the surface of the silicon wafer 62.₂Film). At this time, the HF that has flowed into the processing chamber 60 together with radical oxygen atoms reacts with the naturally formed film combined with hydrogen, fluorine, etc. existing on the surface of the silicon wafer 62 to remove them.
[0028]
That is, HF exists on the surface of the silicon wafer 62 [Si_X, Si_Y, Si (OH)_ZAnd a film made of
[Chemical formula 5]

The undesired spontaneously formed film existing on the surface of the silicon wafer 62 is removed. For this reason, the silicon oxide film formed by reacting with active oxygen becomes a high-quality insulating film with high insulating performance because the naturally formed film is removed.
[0029]
Moreover, in the embodiment, before supplying the reactive fluorine-based gas that is a reactive halogen-based gas and the source gases such as oxygen and ozone to the processing chamber 60 in which the silicon wafer 62 is disposed, gas mixing is performed. Since they are mixed in the section 52, the two are sufficiently mixed to promote the decomposition of the source gas, the amount of radical oxygen that is the active species of the source gas supplied to the processing chamber 60 is increased, and the film formation rate is increased. Can be increased. In the embodiment, film formation under atmospheric pressure can be performed, and since it is not necessary to form a vacuum, equipment cost and running cost can be reduced, and environmental load can be reduced. In the embodiment, the film can be formed at a temperature much lower than that of the conventional thermal oxidation, and the equipment can be simplified and the energy can be reduced. Furthermore, in embodiments, the stable CF with poor reactivity_FourSince the reactive fluorine-based gas is obtained in the discharge unit 12 using the gas, the handling is easy and the safety of work can be improved. Moreover, since the reactive fluorine-based gas generated in the discharge unit 12 is transported to the processing chamber 60 different from the discharge unit 12 to form a film, there is no possibility that the silicon wafer 62 is damaged by the discharge. Further, since the processing chamber 60 is heated, the moisture introduced into the processing chamber 60 can prevent the moisture generated by the reaction in the processing chamber 60 from condensing, and can stably form a film. A good quality silicon oxide film can be obtained.
[0030]
<< Formation of silicon oxynitride film >>
Similar to the formation of the silicon oxide film, the cleaned silicon wafer 62 is placed on the processing stage 64 and maintained at a predetermined temperature. Then, CF is supplied from the stable halogen supply unit 18 to the discharge unit 12._FourSupply. This CF_FourA part of is supplied through the first water bubbling unit 22 in the same manner as described above, and the discharge unit 12 generates a reactive fluorine-based gas. Further, nitrogen gas, which is a raw material gas, is supplied to the halogen supply pipe 28 from the nitrogen gas supply source 38 through the nitrogen supply pipe 30. However, a part of the nitrogen gas from the nitrogen gas supply source 38 passes through the second water bubbling unit 44, adds water, and flows into the halogen supply pipe 28. Further, as in the case of the formation of the silicon oxide film, oxygen gas, which is a raw material gas from the oxygen gas supply source 48, is supplied to the ozone generator 50 to partially convert it to ozone, and then gas mixing in the halogen supply pipe 28 is performed. Supplied to the unit 52. Further, argon gas is supplied from the argon gas supply source 56 to the halogen supply pipe 28 as a diluent gas.
[0031]
The reactive fluorine-based gas generated in the discharge unit 12 reacts with oxygen and ozone in the gas mixing unit 52 as follows.
[Chemical 6]

[Chemical 7]

Furthermore, the F generated in this way₂Nitrogen gas with moisture,
[Chemical 8]

In this way, active NO is generated. This NO flows into the processing chamber 60 together with active oxygen (O),
[Chemical 9]

Thus, the silicon oxynitride film is formed by reacting with silicon. At this time, the HF supplied to the processing chamber 60 reacts with the naturally formed film existing on the surface of the silicon wafer 62 and is removed as described above. Therefore, the same effect as the formation of the silicon oxide film can be obtained.
[0032]
<< Formation of silicon nitride film >>
In the same manner as described above, the silicon wafer 62 is placed on the processing stage 64. Then, the discharge unit 12 has CF_FourAnd water (water) are supplied to generate a reactive fluorine-based gas. Further, oxygen gas and ozone are not supplied to the halogen supply pipe 28, and only nitrogen gas and argon gas are supplied. The nitrogen gas does not pass through the second water bubbling unit 44 so that moisture is not supplied to the halogen supply pipe 28. As a result, HF and CO shown in Chemical Formula 1 are obtained.₂Reacts with nitrogen gas as follows to generate nitrogen single atoms as active species.
[Chemical Formula 10]

In addition, nitrogen single atom
Embedded image

Thus, a silicon nitride film is formed. In this case, the same effect as described above can be obtained.
[0033]
In the above embodiment, the case where the workpiece is the silicon wafer 62 has been described. However, the workpiece may be a semiconductor such as polycrystalline silicon, amorphous silicon, germanium, and various types such as aluminum, copper, and tantalum. An insulator such as metal or various ceramics may be used. In the above embodiment, the case where the insulating film is formed on the silicon wafer 62 has been described. However, the present invention can be applied to manufacture of various device thin films such as ITO (Indium Tin Oxide) and magnetic thin films. . In the above-described embodiment, the case where the silicon wafer 62 is disposed in the processing chamber 60 to form a film has been described. However, the silicon wafer 62 may be disposed in an open system outside the processing chamber to perform the film forming process. . Furthermore, in the above-described embodiment, the case where the halogen-based gas is a fluorine-based gas has been described. However, depending on the material of the workpiece, other halogen-based gases such as a chlorine-based gas and a bromine-based gas can be used.
[0034]
FIG. 3 shows another embodiment of the gas mixing section. The gas mixing unit 100 according to this embodiment is provided with stirring means. That is, the gas mixing unit 100 is provided with a fan 104 that is rotationally driven by the motor 102 inside the mixing chamber 106 so that the gas flowing into the mixing chamber 106 can be stirred. In the gas mixing section 100 thus configured, the reactive fluorine-based gas and the raw material gas (nitrogen gas or / and oxygen gas, ozone) can be mixed more rapidly and sufficiently, and the activity of the raw material gas can be increased. More seeds can be added.
[0035]
FIG. 4 shows a main part of another embodiment. The film forming apparatus 110 shown in FIG. 4 is provided with a booster 114 such as a blower or a compressor on the downstream side of the connection part 112 of the halogen supply pipe 28 to the argon supply pipe 34, and supplies it to the processing chamber 60. The film forming process gas can be boosted. The exhaust pipe 68 connected to the processing chamber 60 is provided with a pressure control valve 116 so that the pressure in the processing chamber 60 can be maintained at a predetermined value. Further, the processing chamber 60 is provided with a pressure sensor 118 so that the pressure in the processing chamber 60 can be detected. The output signal of the pressure sensor 118 is input to the controller 122 that controls the motor 120 that drives the booster 114. Based on the detection signal output from the pressure sensor 118, the controller 122 drives the booster 114 via the motor 120 so that the pressure in the processing chamber 60 becomes a set value.
[0036]
The film forming apparatus 110 according to the embodiment configured as described above can set the inside of the processing chamber 60 to a pressure higher than the atmospheric pressure, and can control the amount of active species of the film forming processing gas supplied to the processing chamber 60. It is possible to increase the number, and the film formation rate can be further increased.
[0037]
【Example】
Film formation experiments were performed using an apparatus similar to the film formation apparatus 10 shown in FIG. The processing chamber 60 used for the film formation experiment has a volume of 80 mL formed in a cylindrical shape with aluminum. And the workpiece | work arrange | positioned in the process chamber 60 used the single crystal silicon (sample) whose one side is 20 mm. The discharge unit 12 has a length L of the discharge part 80 shown in FIG. 2 of 40 mm, a width D of the discharge part 80 of 70 mm, and a thickness t of the electrode teeth 88 and 90 of the upper and lower electrodes 82 and 84. Is 1 mm, the height h is 3 mm, and the length in the direction perpendicular to the paper surface of FIG. 2B is 40 mm. Furthermore, the gas flow paths 92 and 94 have a square cross section with a width of 3 mm and a height of 3 mm. The insulating plate 86 is made of alumina (Al₂O_Three), And the thickness d is 1 mm. The voltage applied between the upper electrode 82 and the lower electrode 84 has a frequency of 15 to 20 kHz and a voltage value of 10 kV as a pp value.
[0038]
After the sample was placed in the processing chamber 60, the temperature inside was increased from room temperature to 200 ° C. as shown in FIG. The temperature rising rate is 35-40 ° C./min. Then, when the inside of the processing chamber 60 reached 200 ° C., dry nitrogen gas was supplied into the processing chamber at a rate of 10 L / min for 10 minutes, and replacement with nitrogen gas was performed. Thereafter, the supply of nitrogen gas was stopped, and a film forming process gas to be described later was supplied for 90 minutes to form an oxide film, an oxynitride film, and a nitride film on the surface of the sample. Then, at the stage where the film formation test for 90 minutes was completed, nitrogen gas was again supplied to the processing chamber 60 at a rate of 10 L / min, and replacement with nitrogen gas was performed for 10 minutes while cooling to room temperature. The discharge in the discharge unit 12 and the film forming process in the processing chamber 60 are both performed at atmospheric pressure. These conditions were applied to the following examples.
[0039]
Example 1
After the inside of the processing chamber 60 is replaced with nitrogen gas as described above, the discharge unit 12 is charged with 100 mL / min of CF._FourSupplied. However, half of 50 mL / min was introduced into the first water bubbling unit 22 and supplied to the discharge unit 12 with moisture. Further, 200 mL / min of oxygen gas was supplied from the oxygen gas supply source 48 to the ozone generator 50, and a part of the oxygen gas was converted to ozone and supplied to the gas mixing unit 52 of the halogen supply pipe 28. Therefore, the supplied oxygen and ozone and F_FourThe ratio to (O₂/ O_Three: CF_Four= 2: 1.
[0040]
However, nitrogen gas was not supplied from the nitrogen gas supply source 38 to the halogen supply pipe 28. In addition, the production | generation ratio of the ozone by the ozone generator 50 was 2.3 volume% in the case of 100% oxygen gas.
[0041]
When the film forming gas generated under such conditions was supplied to the processing chamber 60 and the film forming process of the sample was performed for 90 minutes, a silicon oxide film was formed on the surface of the sample. When this silicon oxide film was analyzed, the naturally formed film containing hydrogen and fluorine accompanying wet cleaning was removed, and a very high quality silicon oxide film could be formed.
[0042]
Example 2
Similarly to Example 1, 200 mL / min of oxygen gas is supplied from the oxygen gas supply source 48 to the mixing unit 52 provided in the halogen supply pipe 28 via the ozone generator 50, and CF is supplied from the stable halogen supply unit 18._FourWas supplied to the discharge unit 12 at 50 mL / min, and nitrogen gas was supplied from the nitrogen gas supply source 38 to the halogen supply pipe 28 at 50 mL / min. Therefore, the flow rate ratio of each gas is (O₂/ O_Three: N₂: CF_Four= 4: 1: 1. However, CF_FourThe nitrogen gas is a dry gas in which 25 mL / min of half of the supply amount does not pass through the water bubbling unit, and the other half of 25 mL / min passes through the first water bubbling unit 22 or the second water bubbling unit 44. It is a wet gas with moisture.
[0043]
When the film forming process gas generated as described above is supplied to the processing chamber 60 and the film forming process is performed for 90 minutes, silicon (Si), oxygen (O), A silicon oxynitride film made of nitrogen (N) could be formed. Even in this case, the naturally formed film due to the influence of cleaning was removed, and an insulating film having excellent insulating characteristics could be obtained.
[0044]
Example 3
CF which is a stable fluorine-based gas from the stable halogen supply unit 18 to the discharge unit 12_FourThe reactive fluorine-type gas was produced | generated by discharge. CF supplied to the discharge unit 12_FourThe dry gas not containing moisture is 50 mL / min, and the wet gas containing moisture that has passed through the first water bubbling unit 22 is 50 mL / min. Further, dry nitrogen gas that does not pass through the second water bubbling unit 44 at 200 mL / min from the nitrogen gas supply source 38 was supplied to the halogen supply pipe 28. Therefore, the source gas, nitrogen gas and CF_FourThe ratio is N₂: CF_Four= 2: 1.
[0045]
A film forming gas generated by such a gas is supplied to the processing chamber 60 and the film forming process is performed for 90 minutes. As a result, the surface of the sample made of single crystal silicon is made of silicon (Si) and nitrogen (N). A silicon nitride film was formed. Further, in the film formation performed in this manner, the naturally formed film on the sample surface was removed in the same manner as in the previous example, and the formed silicon nitride film showed excellent insulation.
[0046]
Example 4
FIG. 6 shows the relationship between the type of deposition gas and the deposition rate. The apparatus used, the temperature conditions, the sample, and the like are the same as those in each of the above embodiments, and only the film forming gas is different.
[0047]
In the lower part of FIG. 6, oxygen gas from the oxygen gas supply source 48 is supplied to the gas mixing unit through the ozone generator 50 at 200 mL / min, and argon gas supply source 56 is supplied with 100 mL / min. This is the result of film formation performed by supplying argon gas to the halogen supply pipe 28 and introducing these mixed gases into the processing chamber 60. However, CF from the stable halogen supply unit 18_FourAnd supply of nitrogen gas from the nitrogen gas supply source 38 are not performed. In this case, the film formation process was performed for 90 minutes, but the film formation was not performed because of the measurement error range.
[0048]
N in FIG.₂As shown, the results of the film formation process using oxygen gas, ozone, and nitrogen gas are shown. That is, 100 mL / min of nitrogen gas is supplied from the nitrogen gas supply source 38 to the halogen supply pipe, and 200 mL / min of oxygen gas is supplied from the oxygen gas supply source 48 to the halogen supply pipe 28 via the ozone generator 50. After mixing in the gas mixing unit 52, the gas was introduced into the processing chamber 60. However, nitrogen gas was supplied in a wet state via the second water bubbling unit 44. In this case, the film forming process was performed for 90 minutes, but a film forming speed of about 0.1 angstrom / minute (min) was obtained, which was almost in the measurement error range.
[0049]
Figure 6 shows CF_Four(DRY) indicates that CF dried from the stable halogen supply unit 18 to the discharge unit 12_FourAt 100 mL / min and F is discharged by gas discharge in the discharge unit 12.₂A reactive fluorine-based gas such as the above is generated, and an oxygen gas of 200 mL / min is supplied from the oxygen gas supply source 48 to the halogen supply pipe 28 via the ozone generator 50, and these mixed gases are used as a film forming gas. As a result when the film is supplied to the processing chamber 60 and the film forming process is performed for 90 minutes. Also in this case, as is apparent from the figure, the film formation rate was approximately within the measurement error range and about 0.2 angstrom / min.
[0050]
N in FIG.₂+ CF₂(H₂O) indicates that the discharge unit 12 is wet CF via the first water bubbling unit 22._FourIs supplied to the 50 mL / min halogen supply pipe 28 from the nitrogen gas supply source 38 through the second water bubbling unit 44. Furthermore, 200 mL / min of oxygen gas is supplied from the oxygen gas supply source 48 to the ozone generator 50, and the mixed gas of oxygen gas and ozone is supplied to the gas mixing unit 52, and the film forming gas based on these mixed gases is supplied. The result of introducing into the processing chamber 60 and performing the film forming process for 90 minutes is shown. In this case, a silicon oxynitride film was formed, and the film formation rate was significantly increased, and a film formation rate of about 1.45 Å / min could be obtained. However, argon which is a dilution gas is not supplied.
[0051]
Figure 6 shows CF_Four(H₂O) shows a wet CF obtained by passing the first water bubbling unit 22 through the discharge unit 12._FourIs supplied at 100 mL / min to generate a reactive fluorine-based gas, and oxygen gas 200 mL / min from the oxygen gas supply reduction 48 is converted into a mixed gas of oxygen gas and ozone through the ozone generator 50 to supply halogen. This is a result of introducing a film forming gas obtained by supplying the tube 28 into the processing chamber 60 and performing a film forming process for 90 minutes. Note that nitrogen gas and argon gas are not added to the film forming gas. In this case, a silicon oxide film was formed on the surface of the sample made of silicon. The deposition rate of the silicon oxide film was about 1.6 angstrom / min.
[0052]
【The invention's effect】
As described above, according to the present invention, the reactive gas is activated by the reactive halogen gas by adding the reactive halogen gas to the raw material gas that reacts with the workpiece to form a film on the surface of the workpiece. At the same time, since the film bonded with hydrogen and fluorine, which is a residue from the wet cleaning on the surface of the workpiece, is removed by the reactive halogen-based gas, the removal of these naturally formed films and the raw materials Film formation by gas reaction can be performed at the same time, and a film with excellent quality can be formed.
[Brief description of the drawings]
FIG. 1 is an explanatory diagram of a film forming apparatus according to an embodiment of the present invention.
FIG. 2 is a detailed explanatory diagram of a discharge unit according to the embodiment.
FIG. 3 is an explanatory diagram of a gas mixing unit according to another embodiment.
FIG. 4 is an explanatory diagram of a main part of a film forming apparatus according to another embodiment.
FIG. 5 is an explanatory diagram of a temperature profile in an example.
FIG. 6 is a diagram showing a relationship between a film forming gas and a film forming speed in Examples.
[Explanation of symbols]
10, 110 ......... deposition apparatus, 12 ... ... discharge part (discharge unit),
18 ... Halogen gas supply unit (stable halogen supply unit),
22 ..... water supply means (first water bubbling unit),
36 ......... Raw material gas supply section, 38 ... ... Nitrogen gas supply source,
44 ......... Second moisture supply means (second water bubbling unit),
48 ......... Oxygen gas supply source, 50 ......... Ozone generator,
52, 100 ... Gas mixing section, 60 ... Processing chamber,
62 ... Work (silicon wafer), 66 Heating means (heater),
104 ......... Stirring means (fan), 114 ......... Pressure increasing means,
116... Pressure control valve 118 118 Pressure sensor
120... Motor, 122.

Claims (13)

In the method of forming a film on the surface of the workpiece by reacting the workpiece and active species of the source gas, a reactive halogen system is activated by activating a stable halogen-based gas containing moisture at atmospheric pressure by discharge between the electrodes. Generating a gas, adding the source gas to the generated reactive halogen-based gas and mixing them to generate active species of the source gas, and bringing the mixed gas containing the active species into contact with the workpiece A characteristic film forming method.   The film forming method according to claim 1, wherein the workpiece is heated. The workpiece is a silicon film forming method according to claim 1 or 2, wherein the raw material gas is characterized by an oxygen and / or ozone. The workpiece is a silicon film forming method according to claim 1 or 2, wherein the raw material gas is nitrogen. The workpiece is silicon, the material gas is oxygen and / or ozone, and film forming method according to claim 1 or 2, characterized in that a mixed gas of nitrogen. 6. The film forming method according to claim 4 , wherein moisture is added to the nitrogen. The mixed gas, film deposition method according to any one of claims 1 to 6 boosts and wherein the contacting with the workpiece. A discharge part that generates a reactive halogen-based gas by discharge through a stable halogen-based gas containing moisture at atmospheric pressure, and the reactive halogen-based gas generated by the discharge part and a raw material gas are mixed to A gas mixing unit that generates active species of source gas, and a processing chamber in which a work is disposed and a mixed gas containing the active species supplied from the gas mixing unit is brought into contact with the work. Membrane device. The film forming apparatus according to claim 8 , wherein the processing chamber includes a heating unit that heats the workpiece. The film forming apparatus according to claim 8 , wherein the gas mixing unit includes a stirring unit. A moisture supply unit for adding moisture to the stable halogen-based gas is provided between the halogen-based gas supply unit that supplies the stable halogen-based gas to the discharge unit and the discharge unit. The film forming apparatus according to claim 8 . 8. between said gas mixing unit with the raw material gas supply unit for supplying a raw material gas to the gas mixing portion, characterized in that the second water supply means for adding moisture to the feed gas is provided The film-forming apparatus in any one of 11 thru | or 11 . 13. The film forming apparatus according to claim 8 , wherein a pressure increasing unit configured to increase the pressure of the mixed gas is provided between the gas mixing unit and the processing chamber.

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