JP3555737B2 - Cleaning gas - Google Patents
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Description
【０００１】
【発明の属する技術分野】
本発明は、ＣＶＤ法、スパッタリング法、ゾルゲル法、蒸着法を用いて薄膜、厚膜、粉体、ウイスカを製造する装置において装置内壁、冶具等に堆積した不要な堆積物を除去するためのクリーニングガスに関する。
【０００２】
【従来の技術および発明が解決しようとする課題】
半導体工業を中心とした薄膜デバイス製造プロセス、光デバイス製造プロセスや超鋼材料製造プロセスでは、ＣＶＤ法、スパッタリング法、ゾルゲル法、蒸着法を用いて種々の薄膜、厚膜、粉体、ウイスカが製造されている。これらを製造する際には膜、ウイスカや粉体を堆積させるべき目的物上以外の反応器内壁、目的物を担持する冶具等にも堆積物が生成する。不要な堆積物が生成するとパーティクル発生の原因となるため良質な膜、粒子、ウイスカを製造することが困難になるため随時除去しなければならない。
【０００３】
現在、ＣＶＤ装置等の薄膜形成装置のクリーニングには、ＣＦ４、Ｃ２Ｆ６、ＣＨＦ３、ＳＦ６、ＮＦ３などのガスが使用されているが、これらは地球温暖化係数が高いことが問題となっている。また、これらは比較的安定なガスであるため、エッチャントとして有用なＣＦ３・ラジカルやＦ・ラジカル等を発生させるためには、高いエネルギーが必要であり、電力消費量が大きいこと、大量の未反応排ガス処理が困難であるなどの問題がある。
【０００４】
特開平６−１３３５０号公報には、フルオロカーボン側鎖を有するスルホン酸、またはそのハロゲン化物、またはその酸無水物から選ばれる少なくとも１種類の化合物を用いてシリコン化合物層をエッチングすることを特徴とするドライエッチング方法において、具体的には（ＣＦ３ＳＯ２）２Ｏ、ＣＦ３（ＣＦ２）３ＳＯ２Ｆを用いた方法が記載されている。この特開平６−１３３５０号公報は、半導体製造工程における微細ホール加工のためのエッチング工程に関するものであるが、クリーニング工程ではエッチング工程よりもガス化除去するべき対称物質の堆積量・体積膜厚が大きいためより高速な反応速度が求められる。しかしながら、この上記公報記載の化合物では反応速度が遅く、本発明者等が目的とするクリーニング工程には適応できない。また、クリーニング工程では、エッチング工程よりも使用するガス量が多いため、当該上記公報に記載の化合物では、炭素が配管内や反応器の低温部などで堆積が起こり、クリーニングによる反応系の２次的汚染を引き起こす等の問題がある。
【０００５】
【課題を解決するための具体的手段】
本発明者らは、鋭意検討の結果、ＣＦ３ＳＯ２Ｆ、Ｃ２Ｆ５ＳＯ２Ｆは、反応速度が高く、クリーニング能力に優れ、かつクリーニングによる２次的カーボン汚染を起こすことが無くクリーンなクリーニングを行えることを見いだし、さらに酸素との混合ガスを用いることで、より優れたクリーニングを行えることを見いだし本発明に至ったものである。
【０００６】
すなわち本発明は、薄膜形成装置の中に生成した不要な堆積物を除去するために、ＣＦ3ＳＯ2Ｆ、Ｃ2Ｆ5ＳＯ2Ｆの少なくとも１種以上のガスを含有したクリーニングガスで、さらに、ＣＦ3ＳＯ2Ｆ、Ｃ2Ｆ5ＳＯ2Ｆの少なくとも１種以上のガスとＯ2とを含有したクリーニングガスを提供するものである。
【０００７】
以下、本発明を詳細に説明する。
ＣＦ３ＳＯ２ＦあるいはＣ２Ｆ５ＳＯ２Ｆを含有するガスを高周波あるいはマイクロ波を発生させることが可能な電極を取り付けた装置内に導入し、クリーニングを行うことにより、Ｂ、Ｐ、Ｗ、Ｓｉ、Ｔｉ、Ｖ、Ｎｂ、Ｔａ、Ｓｅ、Ｔｅ、Ｍｏ、Ｒｅ、Ｏｓ、Ｉｒ、Ｓｂ、Ｇｅ、Ａｕ、Ａｇ、Ａｓ、Ｃｒ及びその化合物、具体的には酸化物、窒化物、炭化物及びこれらの合金をＣＦ４、Ｃ２Ｆ６、ＮＦ３、Ｃ４Ｆ８等の現在汎用的に使用されているガスよりも高速度でエッチングでき、優れたクリーニングを実現できるものである。
【０００８】
また、例えばＣＦ３ＳＯ２Ｆの場合、特にプラズマ状態でなくとも、配管や装置の内部に堆積するＣＶＤ反応の副生成物である粉体やカレット状の堆積物をプラズマレスでクリーニングすることも可能であるという優れた特徴を有する。
【０００９】
さらに、本発明のガスは、プラズマ反応において所望されない地球温暖化ガスであるＣＦ４の生成を分子内に含有する酸素の効果により遊離フッ素とフッ化炭素（ＣＦ３）との結合を回避する効果があるため、２次的な環境汚染の問題もない。さらに、例えばＣＦ３ＳＯ２Ｆは、下式に示したごとくアルカリ水溶液で分解し、固体状のＣＦ３ＳＯ３Ｋとして固定できるため、未反応排ガスが反応系内から環境中に放出される危険性が無く、環境中に放出されても水と徐々に反応し分解するため地球温暖化に寄与しないという優れた特徴を有する。
ＣＦ３ＳＯ２Ｆ ＋ ＫＯＨ → ＣＦ３ＳＯ３Ｋ ＋ ＨＦ
【００１０】
本発明のガスを用いたクリーニング方法は、プラズマクリーニング、マイクロ波プラズマクリーニング、リモートプラズマクリーニング、プラズマレスクリーニングなどの各種ドライクリーニング条件下で実施可能である。
【００１１】
ＣＦ３ＳＯ２ＦおよびＣ２Ｆ５ＳＯ２Ｆは、同伴ガスを用いずとも優れたエッチング、クリーニング能力を示す。しかし、同伴ガスとしてＡｒ、Ｈｅ、Ｎ２、Ｏ２、Ｈ２、Ｆ２などの単体ガスやＣＯ、ＮＯ、Ｎ２Ｏ、ＣＨ４、ＮＨ３などの化合物を適切な割合で混合して使用することも可能である。
【００１２】
ＣＦ３ＳＯ２Ｆ、Ｃ２Ｆ５ＳＯ２Ｆをクリーニングに用いる場合の流量は、１〜１００００ＳＣＣＭの範囲が好ましい。クリーニングは、エッチングと異なり除去すべき不要物の堆積量が多いため、１ＳＣＣＭ未満の供給量では不要物を短時間に除去するには供給するフッ素量が少なく、クリーニングに長時間要するため好ましくない。一方、供給量が１００００ＳＣＣＭより多いと未反応排ガス量が著しく多くなるため効率的に除害できなくなる。また、プラズマを発生させる反応器内部の圧力は、０．０１〜５０Ｔｏｒｒの範囲が好ましい。０．０１Ｔｏｒｒ未満では反応速度が低下し、高速なクリーニングが困難になり、５０Ｔｏｒｒを越えると良好なプラズマ状態を維持できなくなる。しかし、配管の中などのフッ素ガスプラズマが到達しない箇所のクリーニングを行う場合や反応器をプラズマレスクリーニングする場合、ガス圧力は、０．１〜７６０Ｔｏｒｒの範囲からプロセスに適合可能なエッチング速度が得られる圧力を選択できる。ＣＦ３ＳＯ２Ｆ、Ｃ２Ｆ５ＳＯ２Ｆと金属やその化合物との反応速度は、０．１Ｔｏｒｒ〜５Ｔｏｒｒ以下の圧力領域では圧力に比例するが、０．１Ｔｏｒｒ未満では急速に反応速度が低下する傾向があるため好ましくない。また、５Ｔｏｒｒ以上の圧力領域では、０．１〜５Ｔｏｒｒの領域よりも圧力上昇に対する反応速度の増加割合は小さいが、圧力の上昇に伴って直線的に反応速度も増加する。但し、７６０Ｔｏｒｒ以上の圧力でクリーニングすることは反応系外へのガスの漏洩の可能性があり安全上好ましくない。
【００１３】
次に、ＣＦ3ＳＯ2Ｆ、Ｃ2Ｆ5ＳＯ2Ｆの少なくとも１種類以上のガスにＯ2を添加することによりクリーニングがさらに効果的になる。酸素ガスを添加した場合、遊離Ｆの発生量を増加させると共に遊離Ｆの長寿命化が図れ、さらに遊離フッ化炭素と結合するためＣＦ4の発生を殆ど完全に回避できる。
【００１４】
ＣＦ3ＳＯ2Ｆ、Ｃ2Ｆ5ＳＯ2ＦとＯ2を添加したガスをクリーニングに用いる場合の流量、その他の条件は、Ｏ2を混合しない場合と同様である。すなわち、流量は、１〜１００００ＳＣＣＭの範囲が好ましい。また、プラズマを発生させる反応器内部の圧力は、０．０１〜１０Ｔｏｒｒの範囲が好ましい。しかし、配管の中などのフッ素ガスプラズマが到達しない箇所のクリーニングを行う場合や反応器をプラズマレスクリーニングする場合はガス圧力は、０．１〜７６０Ｔｏｒｒの範囲からプロセスに適合可能なエッチング速度が得られる圧力を選択できる。同伴ガスとしてＯ2を用いるときは、ＣＦ3ＳＯ2Ｆなどの流量１００対して、１〜１００の流量の割合で用いることが好ましい。割合が１未満であるとＯ2の添加効果が顕著には認められず、１００より大きいと堆積物の酸化が優先的に起こるため反応速度が低下するようになる。
【００１５】
プラズマレスクリーニングを実施する場合の温度条件は、反応器壁に堆積した膜状堆積物を除去しようとした場合、酸素の添加の有無に関係なく室温（２０℃）でも反応し徐々に堆積物はガス化除去可能であるが、１００℃以上の温度に加熱することにより高速に反応除去できるためより好ましい。しかし、金属やセラミックス、樹脂の腐蝕を考慮するとその種類に応じて以下の温度以下でクリーニングすることが好ましい。
【００１６】
オーステナイト系ステンレス：３００℃以下
フェライト系ステンレス：１１０℃以下
ハステロイ、ヘインズなどの高Ｎｉ含有合金：２２５℃
モネル：４６５℃
Ｎｉ：５２０℃
Ｎｉ−Ｃｒ鋼：２４５℃
アルミ（及びアルミ合金）：５００℃
窒化アルミ（及び窒化アルミ含有複合材料）：７００℃
アルミナ（及びアルミナ含有複合材料）：７００℃
炭素珪素：４９０℃
黒鉛、硝子状炭素：３９５℃
パーフルオロエラストマ：３６５℃
フッ素ゴム：１８０℃
炭化水素系樹脂：１５０℃
塩化ビニール樹脂：１８０℃
【００１７】
【実施例】
以下、本発明を実施例により詳細に述べるが、かかる実施例により制限されるものではない。
【００１８】
実施例１〜１７
Ａｌ５０５２板状に熱ＣＶＤで、Ｗ、ＷＳｉ、Ｍｏ、Ｒｅ、Ｔｉ、ＴｉＣ、ＴｉＮ、多結晶Ｓｉ（以下、ｐｏｌｙ−Ｓｉと記す）、Ｇｅ、Ｓｉ３Ｎ４、Ｔａ２Ｏ５、をそれぞれ４０μｍに成膜したサンプル及びプラズマＣＶＤで、アモルファスＳｉ（以下、ａ−Ｓｉ：Ｈと記す）、アモルファスＳｉＮ（以下、ａ−ＳｉＮｘ：Ｈと記す）をそれぞれ４０μｍに成膜したサンプルを製作した。これらのサンプルとシリコウエハ（以下、単結晶Ｓｉと記す）及びシリコンウエハを酸素雰囲気下９２０℃で表面酸化させたシリコン酸化膜付きウエハ（以下、Ｔｈ−ＳｉＯ２と記す）（膜厚；１０μｍ）及びスパッタリングでＡｌ５０５２上に成膜したＣｒ（膜厚２μｍ）、Ａｕ板（厚さ０．１ｍｍ）をコールドウール型プラズマＣＶＤ装置のサセプタ上に設置し、試料を加熱して各々個別に下記条件でエッチング速度の測定を行った。その結果、何れの膜（及びウエハ）も非常に高速にエッチング可能であることが解った。それらの結果を表１に示した。
（条件）
ＣＦ３ＳＯ２Ｆ流量：１０００ＳＣＣＭ
ガス圧力：１５０Ｔｏｒｒ
【００１９】
【表１】
比較例１、２
実施例１で用いたＷと同じ方法で製作した試料を（ＣＦ３ＳＯ２）２Ｏ、ＣＦ３（ＣＦ２）２ＳＯ２Ｆにて同様の条件でエッチング速度を求めた。その結果、（ＣＦ３ＳＯ２）２Ｏでは、０．０３５μｍ／ｍｉｎ、ＣＦ３（ＣＦ２）２ＳＯ２Ｆでは、０．０１５μｍ／ｍｉｎの速度しか得られなかった。
【００２１】
実施例１８〜２１
実施例１で製作したＷ膜を用いて、ＣＦ３ＳＯ２Ｆに酸素、一酸化炭素、一酸化窒素を添加して下記条件でエッチング速度の測定を行った。Ｏ２を添加ガスに用いるとエッチング速度が増加する現象が認められた。それらの結果を表２に示した。（条件）
ＣＦ３ＳＯ２Ｆ流量：１０００ＳＣＣＭ
添加ガス流量：５０ＳＣＣＭ
ガス圧力：１５０Ｔｏｒｒ
【００２２】
【表２】
実施例２２〜２９
Ｂ２Ｏ３、Ｐ２Ｏ５、Ｖ、Ｎｂ、Ａｓの粉体、ポリシラン粉を各々１ｇだけ外熱式Ｎｉ製反応管内に静置し、ＣＦ３ＳＯ２Ｆを反応器内に入れ７６０Ｔｏｒｒで、３０分間反応させた後の試料重量の測定を行った。この結果、室温（１８℃）でも粉体重量は減少しており、配管の中に溜まった粉体もプラズマレスでクリーニング可能であることが解った。それらの結果を表３に示した。
【００２４】
【表３】
実施例３０
高周波電源（１３．５６ＭＨｚ）を備えた平行平板型プラズマＣＶＤ装置を用いて、熱ＣＶＤ法により硝子基板状にＷ（原料ＷＦ６、Ｈ２、成膜温度５００℃）を成膜した後の反応器壁に１〜２０μｍ堆積した膜状不要物及び粉体の除去を下記条件でプラズマクリーニングを試みた。なお、反応器の器壁やサセプタ上には膜状堆積物が付着しており、反応器の底部低温部や配管内には粉体が堆積していた。その後、クリーニングを所定の時間行い、反応器内部、配管の状態を観察した。それらの結果を表４に示した。
【表４】
実施例３１
高周波電源（１３．５６ＭＨｚ）を備えた平行平板型プラズマＣＶＤ装置を用いて、熱ＣＶＤ法により硝子基板状にＷ（原料ＷＦ６、Ｈ２、成膜温度５００℃）を成膜した後の反応器壁に１〜２０μｍ堆積した膜状不要物及び粉体の除去を下記条件でプラズマクリーニングを試みた。なお、反応器の器壁やサセプタ上には膜状堆積物が付着しており、反応器の底部低温部や配管内には粉体が堆積していた。その後クリーニングを所定の時間行い、反応器内部、配管の状態を観察した。それらの結果を表５に示した。
【表５】
実施例３２
高周波電源（１３．５６ＭＨｚ）を備えた平行平板型プラズマＣＶＤ装置を用いて、熱ＣＶＤ法により硝子基板状にＷ（原料ＷＦ６、Ｈ２、成膜温度５００℃）を成膜した後の反応器壁に１〜２０μｍ堆積した膜状不要物及び粉体の除去を下記条件でプラズマクリーニングを試みた。なお、反応器の器壁やサセプタ上には膜状堆積物が付着しており、反応器の底部低温部や配管内には粉体が堆積していた。その後クリーニングを所定の時間行い、反応器内部、配管の状態を観察した。それらの結果を表６に示した。
【表６】
実施例３３〜３９
ＣＦ３ＳＯ２Ｆを用いて、熱ＣＶＤ法により、Ｗ（実施例３３）、ＷＳｉｘ（実施例３４）、Ｔａ２Ｏ５（実施例３５）、ｐｏｌｙ−Ｓｉ（実施例３６）、ＴｉＮ（実施例３７）、Ｓｉ３Ｎ４（実施例３８）、ＳｉＯ２（実施例３９）を成膜した後のコールドウオール型反応器壁に１〜２０μｍ堆積した膜状不要物及び粉体の除去をマイクロ波電源（２．４５ＧＨｚ）を反応器外部に取り付け、リモートプラズマ法により下記条件でクリーニングした。
【００３２】
クリーニング後の反応器内部、配管の状態を観察したところ堆積していた膜及び粉体は完全に除去できていた。
実施例４０〜４６
Ｃ２Ｆ５ＳＯ２Ｆを用いて、熱ＣＶＤ法により、Ｗ（実施例４０）、ＷＳｉｘ（実施例４１）、Ｔａ２Ｏ５（実施例４２）、ｐｏｌｙ−Ｓｉ（実施例４３）、ＴｉＮ（実施例４４）、Ｓｉ３Ｎ４（実施例４５）、ＳｉＯ２（実施例４６）を成膜した後のコールドウオール型反応器壁に１〜２０μｍ堆積した膜状不要物及び粉体の除去をマイクロ波電源（２．４５ＧＨｚ）を反応器外部に取り付け、リモートプラズマ法により下記条件でクリーニングした。
【００３４】
クリーニング後の反応器内部、配管の状態を観察したところ堆積していた膜及び粉体は完全に除去できていた。
【発明の効果】
本発明のクリーニングガスを用いることにより、地球温暖化の問題もなく、高速で清浄なクリーニングを行うことができる。[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a cleaning method for removing unnecessary deposits deposited on inner walls, jigs, and the like of an apparatus for manufacturing a thin film, a thick film, a powder, and a whisker using a CVD method, a sputtering method, a sol-gel method, and an evaporation method. About gas.
[0002]
2. Description of the Related Art
In the thin film device manufacturing process, optical device manufacturing process, and super steel material manufacturing process centered on the semiconductor industry, various thin films, thick films, powders, and whiskers are manufactured using CVD, sputtering, sol-gel, and evaporation methods. Have been. When these are produced, deposits are also formed on the inner wall of the reactor other than on the target on which films, whiskers and powders are to be deposited, jigs carrying the target, and the like. The generation of unnecessary deposits causes the generation of particles, which makes it difficult to produce high-quality films, particles, and whiskers, and must be removed as needed.
[0003]
At present, gases such as CF 4 , C 2 F 6 , CHF 3 , SF 6 , and NF 3 are used for cleaning of a thin film forming apparatus such as a CVD apparatus, but these gases have a high global warming potential. Has become a problem. Further, since these are relatively stable gases, high energy is required to generate CF 3 .radicals, F.radicals, etc. useful as an etchant. There are problems such as difficulty in treating the reaction exhaust gas.
[0004]
JP-A-6-13350 is characterized in that a silicon compound layer is etched using at least one compound selected from a sulfonic acid having a fluorocarbon side chain, a halide thereof, or an acid anhydride thereof. In the dry etching method, specifically, a method using (CF 3 SO 2 ) 2 O and CF 3 (CF 2 ) 3 SO 2 F is described. JP-A-6-13350 relates to an etching step for processing a fine hole in a semiconductor manufacturing process. In a cleaning step, the deposition amount and the volume film thickness of a symmetric substance to be gasified and removed are smaller than those in the etching step. Because of the large size, a faster reaction rate is required. However, the compounds described in the above publications have a low reaction rate and cannot be adapted to the cleaning step aimed at by the present inventors. Further, in the cleaning step, a larger amount of gas is used than in the etching step. Therefore, in the compound described in the above publication, carbon is deposited in a pipe or a low-temperature portion of a reactor, and the secondary of the reaction system due to cleaning is generated. There is a problem such as causing environmental pollution.
[0005]
[Specific means for solving the problem]
As a result of intensive studies, the present inventors have found that CF 3 SO 2 F and C 2 F 5 SO 2 F have a high reaction rate, an excellent cleaning ability, and are free from secondary carbon contamination due to cleaning. The present invention has been found to be able to perform excellent cleaning, and it has been found that more excellent cleaning can be performed by using a mixed gas with oxygen.
[0006]
That is, the present invention provides a cleaning gas containing at least one gas of CF 3 SO 2 F and C 2 F 5 SO 2 F in order to remove unnecessary deposits generated in the thin film forming apparatus. Further, the present invention provides a cleaning gas containing at least one of CF 3 SO 2 F and C 2 F 5 SO 2 F and O 2 .
[0007]
Hereinafter, the present invention will be described in detail.
A gas containing CF 3 SO 2 F or C 2 F 5 SO 2 F is introduced into a device provided with an electrode capable of generating a high frequency or a microwave, and B, P, W is obtained by performing cleaning. , Si, Ti, V, Nb, Ta, Se, Te, Mo, Re, Os, Ir, Sb, Ge, Au, Ag, As, Cr and compounds thereof, specifically, oxides, nitrides, carbides and These alloys can be etched at a higher speed than currently used gases such as CF 4 , C 2 F 6 , NF 3 , and C 4 F 8 and can realize excellent cleaning.
[0008]
Further, for example, in the case of CF 3 SO 2 F, powder or cullet-like deposits, which are by-products of a CVD reaction deposited in a pipe or an apparatus, may be cleaned without plasma, even in a plasma state. It has the excellent feature that it is possible.
[0009]
Furthermore, the gas of the present invention has the effect of avoiding the bond between free fluorine and carbon fluoride (CF 3 ) due to the effect of oxygen contained in the molecule on the formation of CF 4 , an undesirable global warming gas in the plasma reaction. Therefore, there is no problem of secondary environmental pollution. Furthermore, for example, CF 3 SO 2 F can be decomposed with an aqueous alkaline solution and fixed as solid CF 3 SO 3 K as shown in the following formula, and thus there is a risk that unreacted exhaust gas is released from the reaction system into the environment. It has an excellent feature that it does not contribute to global warming because it has a low reactivity and gradually reacts and decomposes with water even if released into the environment.
CF 3 SO 2 F + KOH → CF 3 SO 3 K + HF
[0010]
The cleaning method using the gas of the present invention can be performed under various dry cleaning conditions such as plasma cleaning, microwave plasma cleaning, remote plasma cleaning, and plasma rescreening.
[0011]
CF 3 SO 2 F and C 2 F 5 SO 2 F exhibit excellent etching and cleaning capabilities without using an accompanying gas. However, a simple gas such as Ar, He, N 2 , O 2 , H 2 , F 2 or a compound such as CO, NO, N 2 O, CH 4 , NH 3 is mixed and used at an appropriate ratio as an accompanying gas. It is also possible.
[0012]
When CF 3 SO 2 F or C 2 F 5 SO 2 F is used for cleaning, the flow rate is preferably in the range of 1 to 10000 SCCM. Cleaning, unlike etching, involves a large amount of undesired substances to be removed. Therefore, if the supply amount is less than 1 SCCM, the amount of fluorine to be supplied in order to remove unnecessary substances in a short time is small, and cleaning is undesirably long. On the other hand, if the supply amount is more than 10,000 SCCM, the amount of unreacted exhaust gas becomes extremely large, so that it is not possible to efficiently remove the harmful gas. The pressure inside the reactor for generating plasma is preferably in the range of 0.01 to 50 Torr. If the pressure is less than 0.01 Torr, the reaction speed decreases, and high-speed cleaning becomes difficult. If the pressure exceeds 50 Torr, a good plasma state cannot be maintained. However, in the case of cleaning a portion where the fluorine gas plasma does not reach, such as in a pipe, or performing plasma rescreening of a reactor, the gas pressure is set within a range of 0.1 to 760 Torr to obtain an etching rate compatible with the process. Pressure can be selected. The reaction rate between CF 3 SO 2 F and C 2 F 5 SO 2 F and a metal or a compound thereof is proportional to the pressure in a pressure range of 0.1 Torr to 5 Torr or less, but the reaction rate rapidly decreases below 0.1 Torr. It is not preferable because it tends to decrease. In the pressure range of 5 Torr or more, the rate of increase of the reaction rate with respect to the pressure rise is smaller than in the range of 0.1 to 5 Torr, but the reaction rate increases linearly with the increase of the pressure. However, cleaning at a pressure of 760 Torr or more is not preferable in terms of safety because there is a possibility of gas leaking out of the reaction system.
[0013]
Next, cleaning is made more effective by adding O 2 to at least one gas of CF 3 SO 2 F and C 2 F 5 SO 2 F. When oxygen gas is added, the amount of free F generated can be increased, and the life of free F can be prolonged. Further, the generation of CF 4 can be almost completely avoided because it is combined with free fluorocarbon.
[0014]
The flow rate and other conditions when using a gas to which CF 3 SO 2 F, C 2 F 5 SO 2 F and O 2 are added for cleaning are the same as those when O 2 is not mixed. That is, the flow rate is preferably in the range of 1 to 10000 SCCM. The pressure inside the reactor for generating plasma is preferably in the range of 0.01 to 10 Torr. However, in the case of cleaning a portion where the fluorine gas plasma does not reach, such as in a pipe, or performing plasma rescreening of a reactor, the gas pressure is in the range of 0.1 to 760 Torr, and an etching rate suitable for the process is obtained. Pressure can be selected. When O 2 is used as the accompanying gas, it is preferable to use a flow rate of 1 to 100 with respect to a flow rate of 100 such as CF 3 SO 2 F. When the ratio is less than 1, the effect of adding O 2 is not remarkably recognized, and when it is more than 100, the oxidation of the deposit occurs preferentially, so that the reaction rate is reduced.
[0015]
The temperature conditions for performing plasma rescreening are as follows. When trying to remove film-like deposits deposited on the reactor wall, the reaction occurs at room temperature (20 ° C.) regardless of the presence or absence of oxygen, and the deposits gradually grow. Although gasification removal is possible, heating to a temperature of 100 ° C. or higher is more preferable because reaction can be removed at high speed. However, considering the corrosion of metals, ceramics, and resins, it is preferable to perform cleaning at the following temperature or lower depending on the type.
[0016]
Austenitic stainless steel: 300 ° C or less Ferritic stainless steel: 110 ° C or less High Ni-containing alloys such as Hastelloy and Haynes: 225 ° C
Monel: 465 ° C
Ni: 520 ° C
Ni-Cr steel: 245 ° C
Aluminum (and aluminum alloy): 500 ° C
Aluminum nitride (and composite material containing aluminum nitride): 700 ° C
Alumina (and alumina-containing composite material): 700 ° C
Carbon silicon: 490 ° C
Graphite, glassy carbon: 395 ° C
Perfluoroelastomer: 365 ° C
Fluorine rubber: 180 ° C
Hydrocarbon resin: 150 ° C
Vinyl chloride resin: 180 ° C
[0017]
【Example】
Hereinafter, the present invention will be described in more detail with reference to examples, but the present invention is not limited to these examples.
[0018]
Examples 1 to 17
Al, 5052, W, WSi, Mo, Re, Ti, TiC, TiN, polycrystalline Si (hereinafter referred to as poly-Si), Ge, Si 3 N 4 , and Ta 2 O 5 each having a thickness of 40 μm are formed by thermal CVD. And a sample in which amorphous Si (hereinafter, referred to as a-Si: H) and amorphous SiN (hereinafter, referred to as a-SiNx: H) were formed to a thickness of 40 μm by plasma CVD. These samples, a silicon wafer (hereinafter, referred to as single crystal Si), a wafer with a silicon oxide film (hereinafter, referred to as Th-SiO 2 ) obtained by subjecting a silicon wafer to surface oxidation at 920 ° C. in an oxygen atmosphere (film thickness: 10 μm), and Cr (film thickness 2 μm) and Au plate (thickness 0.1 mm) formed on Al5052 by sputtering are placed on a susceptor of a cold wool type plasma CVD apparatus, and the samples are heated and individually etched under the following conditions. Speed measurements were taken. As a result, it was found that any of the films (and wafers) can be etched at a very high speed. The results are shown in Table 1.
(conditions)
CF 3 SO 2 F flow rate: 1000 SCCM
Gas pressure: 150 Torr
[0019]
[Table 1]
Comparative Examples 1 and 2
The etching rate of a sample manufactured by the same method as that of W used in Example 1 was determined using (CF 3 SO 2 ) 2 O and CF 3 (CF 2 ) 2 SO 2 F under the same conditions. As a result, only (0.035 μm / min) was obtained with (CF 3 SO 2 ) 2 O and only 0.015 μm / min with CF 3 (CF 2 ) 2 SO 2 F.
[0021]
Examples 18 to 21
Using the W film manufactured in Example 1, oxygen, carbon monoxide, and nitrogen monoxide were added to CF 3 SO 2 F, and the etching rate was measured under the following conditions. When O 2 was used as an additive gas, a phenomenon in which the etching rate increased was observed. Table 2 shows the results. (conditions)
CF 3 SO 2 F flow rate: 1000 SCCM
Additive gas flow rate: 50 SCCM
Gas pressure: 150 Torr
[0022]
[Table 2]
Examples 22 to 29
B 2 O 3, P 2 O 5, V, Nb, powder As, respectively polysilane powder was placed in an outer thermal Ni steel reaction tube only 1g, at 760Torr put CF 3 SO 2 F into the reactor After the reaction for 30 minutes, the weight of the sample was measured. As a result, it was found that the powder weight was reduced even at room temperature (18 ° C.), and that the powder accumulated in the pipe could be cleaned without plasma. Table 3 shows the results.
[0024]
[Table 3]
Example 30
Reaction after forming W (raw material WF 6 , H 2 , film formation temperature 500 ° C.) on a glass substrate by thermal CVD using a parallel plate type plasma CVD apparatus equipped with a high frequency power supply (13.56 MHz). Plasma cleaning was attempted under the following conditions to remove film-like undesired substances and powder deposited on the vessel wall at 1 to 20 μm. It should be noted that a film-like deposit had adhered to the vessel wall and the susceptor of the reactor, and powder had accumulated in the low-temperature portion at the bottom of the reactor and in the piping. Thereafter, cleaning was performed for a predetermined time, and the inside of the reactor and the state of the piping were observed. Table 4 shows the results.
[Table 4]
Example 31
Reaction after forming W (raw material WF 6 , H 2 , film formation temperature 500 ° C.) on a glass substrate by thermal CVD using a parallel plate type plasma CVD apparatus equipped with a high frequency power supply (13.56 MHz). Plasma cleaning was attempted under the following conditions to remove film-like undesired substances and powder deposited on the vessel wall at 1 to 20 μm. It should be noted that a film-like deposit had adhered to the vessel wall and the susceptor of the reactor, and powder had accumulated in the low-temperature portion at the bottom of the reactor and in the piping. Thereafter, cleaning was performed for a predetermined time, and the state of the inside of the reactor and the piping were observed. Table 5 shows the results.
[Table 5]
Example 32
Reaction after forming W (raw material WF 6 , H 2 , film formation temperature 500 ° C.) on a glass substrate by thermal CVD using a parallel plate type plasma CVD apparatus equipped with a high frequency power supply (13.56 MHz). Plasma cleaning was attempted under the following conditions to remove film-like undesired substances and powder deposited on the vessel wall at 1 to 20 μm. It should be noted that a film-like deposit had adhered to the vessel wall and the susceptor of the reactor, and powder had accumulated in the low-temperature portion at the bottom of the reactor and in the piping. Thereafter, cleaning was performed for a predetermined time, and the state of the inside of the reactor and the piping were observed. The results are shown in Table 6.
[Table 6]
Examples 33 to 39
W (Example 33), WSix (Example 34), Ta 2 O 5 (Example 35), poly-Si (Example 36), and TiN (Example) by thermal CVD using CF 3 SO 2 F. Example 37) The removal of film-like undesired substances and powder deposited on the wall of the cold wall type reactor after forming a film of Si 3 N 4 (Example 38) and SiO 2 (Example 39) by 1 to 20 μm was carried out by a microscopic method. A wave power supply (2.45 GHz) was attached to the outside of the reactor, and cleaning was performed by the remote plasma method under the following conditions.
[0032]
Observation of the inside of the reactor and the state of the piping after cleaning revealed that the deposited film and powder had been completely removed.
Examples 40 to 46
With C 2 F 5 SO 2 F, by a thermal CVD method, W (Example 40), WSix (Example 41), Ta 2 O 5 (Example 42), poly-Si (Example 43), TiN (Example 44), Removal of film-like unnecessary matter and powder deposited on a cold wall type reactor wall after forming a film of Si 3 N 4 (Example 45) and SiO 2 (Example 46) by 1 to 20 μm. Was installed outside the reactor with a microwave power supply (2.45 GHz), and was cleaned under the following conditions by a remote plasma method.
[0034]
Observation of the inside of the reactor and the state of the piping after cleaning revealed that the deposited film and powder had been completely removed.
【The invention's effect】
By using the cleaning gas of the present invention, high-speed and clean cleaning can be performed without a problem of global warming.
Claims (2)
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP20671098A JP3555737B2 (en) | 1998-07-22 | 1998-07-22 | Cleaning gas |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP20671098A JP3555737B2 (en) | 1998-07-22 | 1998-07-22 | Cleaning gas |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JP2000038676A JP2000038676A (en) | 2000-02-08 |
| JP3555737B2 true JP3555737B2 (en) | 2004-08-18 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP20671098A Expired - Fee Related JP3555737B2 (en) | 1998-07-22 | 1998-07-22 | Cleaning gas |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US9773679B2 (en) | 2013-09-09 | 2017-09-26 | American Air Liquide, Inc. | Method of etching semiconductor structures with etch gas |
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| JP5707144B2 (en) * | 2011-01-18 | 2015-04-22 | 東京エレクトロン株式会社 | Substrate processing apparatus dry cleaning method and metal film removal method |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US9773679B2 (en) | 2013-09-09 | 2017-09-26 | American Air Liquide, Inc. | Method of etching semiconductor structures with etch gas |
| US10115600B2 (en) | 2013-09-09 | 2018-10-30 | L'Air Liquide, Société Anonyme pour l'Etude et l'Exploitation des Procédés Georges Claude | Method of etching semiconductor structures with etch gas |
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| Publication number | Publication date |
|---|---|
| JP2000038676A (en) | 2000-02-08 |
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