JP4101089B2 - Beam source and beam processing apparatus - Google Patents

Description

ここで、αは係数である。
【００４９】
例えば、主として正イオンと加熱された電子とからなるプラズマと、正イオンと負イオンが共存したプラズマにおいて、Ｓａ＜αＳｋのようにすればＶ_ＤＣは正となり、第１電極（オリフィス電極）１の電位がアンテナの電位より低くなるので、プラズマ中の正イオンがこの電位差によってオリフィス電極に向けて加速され、オリフィス電極に形成されたオリフィスに入っていく。オリフィス電極のオリフィスの内部を通過する正イオンは、主として、オリフィスの周壁の固体表面近傍において電子を与えられて中性化されるか、オリフィス電極の表面から放出された電子と衝突して再結合することで中性化されるか、あるいは、オリフィスの内部に残留しているガスとの電荷交換によって中性化されて中性粒子となり、中性粒子ビームを引き出すことが出来る。
【００５０】
同様に、正イオンと負イオンが共存したプラズマにおいて、Ｓａ＞αＳｋのようにすればＶ_ＤＣは負となり、第１電極（オリフィス電極）１の電位がアンテナの電位より高くなるので、プラズマ中の負イオンがこの電位差によってオリフィス電極に向けて加速され、オリフィス電極に形成されたオリフィスに入っていく。オリフィス電極のオリフィスの内部を通過する負イオンは、主として、オリフィスの周壁の固体表面近傍において電子を奪われて中性化され、あるいは、オリフィスの内部に残留しているガスとの電荷交換によって中性化され、中性粒子ビームを引き出すことが出来る。ここで、図７（ｂ）で示すように、高周波電圧の印加と直流電圧の印加の間に、例えば５０μ秒程度の電圧を印加しない負イオン生成時間Ｔを設けてもよい。このようにすると、直流電圧を印加した際にプラズマ中の負イオンの割合が高いので、効率よく大量の負イオンを加速することができる。
【００５１】
また、アンテナの形状は、例えばプラズマ生成室の直径程度の寸法を持つ大口径のらせん状コイルや略円形のループ状コイルの形状であってもよいし、二つ以上のループ状のコイルを並列に接続した形状であってもよい。また、大口径のコイルはインピーダンスが大きくなるので、複数個の小型のアンテナを設置するようにしてもよい。このように、アンテナは、その適正配置によりプラズマ生成室内に均一なプラズマを生成できれば良いので、その構造、形態は問わない。
【００５２】
このように、中性粒子ビームを引き出すことができるので被処理物に対しチャージアップ現象を引き起こさないチャージフリーなビーム源を実現でき、且つプラズマからの放射光を第１電極（オリフィス電極）で遮蔽することのできるビーム源を実現できた。即ち、チャージアップ現象に起因する損傷や放射光による損傷のないダメージフリーなビーム源を実現できる。加えて、ビームを引き出すのに必要となる一対の電極の片方をアンテナが兼ねることで、電極とアンテナの取り合い（相互干渉）を考慮する必要が無くなる。したがって、プラズマ密度が均一になるようにプラズマ生成室の任意の場所にアンテナを配置することができる。よって、大口径で均一なプラズマの生成と、プラズマからの中性粒子ビームの引き出しの両方が簡単な構成で実現可能である。
【００５３】
次に、本発明に係るビーム源の第４の実施形態について図８を参照して説明する。なお、上述の第１の実施形態における部材又は要素と同一の作用又は機能を有する部材又は要素には同一の符号を付し、特に説明しない部分については第１の実施形態と同様である。
図８（ａ）に示すように、このビーム源は、円筒状のプラズマ生成室４と、前記プラズマ生成室４下端に配置された第１電極１と、前記プラズマ生成室４内にプラズマを生成する前記プラズマ生成室４内に配置されたアンテナ２を備えている。
【００５４】
前記プラズマ生成室４の壁面は、石英ガラス又はセラミック、金属などから選択された材料で構成される。このプラズマ生成室４には、プラズマ生成室４内にガスを導入する図示しないガス導入ポートが設けられており、このガス導入ポートは図示しないガス供給配管と図示しないガス供給源とともにガス供給手段を構成している。このガス供給手段からはＳＦ_６，ＣＨＦ_３，ＣＦ_４，Ｃｌ_２，Ａｒ，Ｏ_２，Ｎ_２，Ｃ_４Ｆ_８などのガスがプラズマ生成室４内に供給される。
前記第１電極１は、グラファイトなどの導電体で形成されたオリフィス板（オリフィス電極）であり、このオリフィス電極は接地電位とされる。このオリフィス電極は第１電極として機能する他、ビームを構成する粒子の中性化手段としても機能するものである。
【００５５】
ここで、このビーム源は、第１電極（オリフィス電極）１を介して図示しない真空チャンバに接続されており、該真空チャンバは、これに接続された真空ポンプにより減圧されている。プラズマ生成室４内の圧力は、主としてこの真空チャンバに接続された真空ポンプの排気量と、オリフィス電極のコンダクタンス、供給されるガスの種類やその流量によって決まる。
【００５６】
前記アンテナ２は、例えばプラズマ生成室４内部の上端に第１電極１に対向して配置された誘導結合型のコイルであり、表面が誘電体９により覆われている。このアンテナ２の形態は、自身の冷却のために水冷パイプの形態をもつものであってもよい。また、このアンテナ２の形態は、例えば図８（ｂ）に示すように銅パイプ２ａに石英などの一種以上の誘電体膜２ｃを被覆した形態でもよいし、図８（ｃ）に示すように銅パイプ２ａをガスや真空等の中空部２ｄを介して誘電体の管２ｅで覆った形態にしてもよい。
【００５７】
このアンテナは、図示しないマッチングボックスを介して高周波電源３に接続されており、例えば、１３．５６ＭＨｚの高周波電圧がアンテナに印加される。これらのアンテナ、マッチングボックス、高周波電源３によってプラズマ生成手段が構成されている。即ち、アンテナに高周波電流を流すことで誘導磁場を生じさせ、磁界の時間変化が電界を誘導し、その電界で電子が加速されてプラズマが生成される。このようにして、プラズマは、該プラズマを生成するアンテナ２をプラズマ生成室の適切な位置に配置することにより、プラズマ生成室内に均一に生成できる。
ここで、第１の実施形態において説明したように、高周波電源３からの高周波電圧の供給方法により、主として正イオンと加熱された電子とからなるプラズマと、正イオンと負イオンが共存したプラズマの、二種類のプラズマを生成することができる。
【００５８】
上記アンテナ２は、例えば周波数６００ｋＨｚの低周波のバイアス電源６にも接続されている。このバイアス電源６は、高周波電源３と共に電圧印加手段を構成し、図７（ａ）に示すように、高周波電源３からの高周波電圧とバイアス電源６からの低周波電圧とを交互にアンテナに印加することができる。ここで、低周波電圧を印加している時間は、プラズマが消滅するよりも十分に短い時間である。そうすると、アンテナの表面が誘電体により覆われているので、低周波電圧の印加の際にアンテナ２と第１電極１の間にセルフバイアス電圧が発生しビームの引き出しを行なうことができる。したがって、高周波電圧の印加によってプラズマを生成した後に、低周波電圧の印加によってビームを引き出すという一連の操作の繰り返しを行なうことが出来る。
【００５９】
ここで、セルフバイアス電圧の直流成分Ｖ_ＤＣは、第１電極１の面積Ｓａと、アンテナを覆う誘電体の表面積Ｓｌと、バイアス電源６の電圧の振幅Ｖによって、簡易的には式（２）の様になると考えられる。
【数２】

【００６０】
例えば、主として正イオンと加熱された電子とからなるプラズマと、正イオンと負イオンが共存したプラズマにおいて、Ｓａ＜ＳｌのようにすればＶ_ＤＣは正となり、第１電極（オリフィス電極）１の電位がアンテナの電位より低くなるので、プラズマ中の正イオンがこの電位差によってオリフィス電極に向けて加速され、オリフィス電極に形成されたオリフィスに入っていく。オリフィス電極のオリフィスの内部を通過する正イオンは、主として、オリフィスの周壁の固体表面近傍において電子を与えられて中性化されるか、オリフィス電極の表面から放出された電子と衝突して再結合することで中性化されるか、あるいは、オリフィスの内部に残留しているガスとの電荷交換によって中性化されて中性粒子となり、中性粒子ビームを引き出すことが出来る。
【００６１】
同様に、正イオンと負イオンが共存したプラズマにおいて、Ｓａ＞ＳｌのようにすればＶ_ＤＣは負となり、第１電極（オリフィス電極）１の電位がアンテナの電位より高くなるので、プラズマ中の負イオンがこの電位差によってオリフィス電極に向けて加速され、オリフィス電極に形成されたオリフィスに入っていく。オリフィス電極のオリフィスの内部を通過する負イオンは、主として、オリフィスの周壁の固体表面近傍において電子を奪われて中性化され、あるいは、オリフィスの内部に残留しているガスとの電荷交換によって中性化され、中性粒子ビームを引き出すことが出来る。ここで、図７（ｂ）で示すように、高周波電圧の印加と直流電圧の印加の間に、例えば５０μ秒程度の電圧を印加しない負イオン生成時間Ｔを設けてもよい。このようにすると、直流電圧を印加した際にプラズマ中の負イオンの割合が高いので、効率よく大量の負イオンを加速することができる。
【００６２】
また、アンテナの形状は、例えばプラズマ生成室の直径程度の寸法を持つ大口径のらせん状コイルや略円形のループ状コイルの形状であってもよいし、二つ以上のループ状のコイルを並列に接続した形状であってもよい。また、大口径のコイルはインピーダンスが大きくなるので、複数個の小型のアンテナを設置するようにしてもよい。このように、アンテナは、その適正配置によりプラズマ生成室内に均一なプラズマを生成できれば良いので、その構造、形態は問わない。
【００６３】
このように、中性粒子ビームを引き出すことができるので被処理物に対しチャージアップ現象を引き起こさないチャージフリーなビーム源を実現でき、且つプラズマからの放射光を第１電極（オリフィス電極）で遮蔽することのできるビーム源を実現できる。即ち、チャージアップ現象に起因する損傷や放射光による損傷のないダメージフリーなビーム源を実現できる。加えて、ビームを引き出すのに必要となる一対の電極の片方をアンテナが兼ねることで、電極とアンテナの取り合いを考慮する必要が無くなる。したがって、プラズマ密度が均一になるようにプラズマ生成室の任意の場所にアンテナを配置することができるので、大口径で均一なプラズマの生成と、プラズマからの中性粒子ビームの引き出しの両方が簡単な構成で実現可能である。
【００６４】
次に、本発明に係るビーム源の第５の実施形態について図９を参照して説明する。なお、上述の第１の実施形態における部材又は要素と同一の作用又は機能を有する部材又は要素には同一の符号を付し、特に説明しない部分については第１の実施形態と同様である。
図９に示すように、このビーム源は、円筒状のプラズマ生成室４と、前記プラズマ生成室４下端に配置された第１電極１と、前記プラズマ生成室４内にプラズマを生成する前記プラズマ生成室４内に配置されたアンテナ２とを備えている。
【００６５】
前記プラズマ生成室４の壁面は、石英ガラス又はセラミック、金属などから選択された材料で構成される。このプラズマ生成室４には、プラズマ生成室４内にガスを導入する図示しないガス導入ポートが設けられており、このガス導入ポートは図示しないガス供給配管と図示しないガス供給源とともにガス供給手段を構成している。このガス供給手段からはＳＦ_６，ＣＨＦ_３，ＣＦ_４，Ｃｌ_２，Ａｒ，Ｏ_２，Ｎ_２，Ｃ_４Ｆ_８などのガスがプラズマ生成室４内に供給される。
前記第１電極１は、グラファイトなどの導電体で形成されたオリフィス板（オリフィス電極）であり、このオリフィス電極は接地電位とされる。このオリフィス電極は第１電極として機能する他、ビームを構成する粒子の中性化手段としても機能するものである。
ここで、このビーム源は、第１電極（オリフィス電極）１を介して図示しない真空チャンバに接続されており、該真空チャンバは、これに接続された真空ポンプにより減圧されている。プラズマ生成室４内の圧力は、主としてこの真空チャンバに接続された真空ポンプの排気量と、オリフィス電極のコンダクタンス、供給されるガスの種類やその流量によって決まる。前記アンテナ２は、例えばプラズマ生成室４内部の上端に第１電極１に対向して配置された誘導結合型のコイルである。このアンテナ２の形態は、自身の冷却のために水冷パイプの形態をもつものであってもよい。
【００６６】
このアンテナ２は、図示しないマッチングボックスを介して高周波電源３に接続されており、例えば、１３．５６ＭＨｚの高周波電圧がアンテナに印加される。これらのアンテナ２、マッチングボックス、高周波電源３によってプラズマ生成手段が構成されている。即ち、アンテナに高周波電流を流すことで誘導磁場を生じさせ、磁界の時間変化が電界を誘導し、その電界で電子が加速されてプラズマが生成される。このようにして、プラズマは、該プラズマを生成するアンテナをプラズマ生成室の適切な位置に配置することにより、プラズマ生成室内に均一に生成できる。ここで、第１の実施形態において説明したように、高周波電源３からの高周波電圧の供給方法により、主として正イオンと加熱された電子とからなるプラズマと、正イオンと負イオンが共存したプラズマの、二種類のプラズマを生成することができる。
【００６７】
上記アンテナ２は、例えば周波数６００ｋＨｚの低周波のバイアス電源６に例えばコンデンサなどの誘電体６ｃを介して接続されている。このバイアス電源６は、高周波電源３と共に電圧印加手段を構成し、図７（ａ）に示すように、高周波電源３からの高周波電圧とバイアス電源６からの低周波電圧とを交互にアンテナ２に印加することができる。ここで、低周波電圧を印加している時間は、プラズマが消滅するよりも十分に短い時間である。そうすると、アンテナが誘電体を介してバイアス電源６に接続されているので、低周波電圧の印加の際にアンテナ２と第１電極１の間にセルフバイアス電圧が発生しビームの引き出しを行なうことができる。したがって、高周波電圧の印加によってプラズマを生成した後に、低周波電圧の印加によってビームを引き出すという一連の操作の繰り返しを行なうことが出来る。
ここで、セルフバイアス電圧の直流成分Ｖ_ＤＣは、第１電極１の面積Ｓａと、アンテナ２の表面積Ｓｍと、バイアス電源６の電圧の振幅Ｖによって、簡易的には式（３）の様になると考えられる。
【数３】

【００６８】
例えば、主として正イオンと加熱された電子とからなるプラズマと、正イオンと負イオンが共存したプラズマにおいて、Ｓａ＜ＳｍのようにすればＶ_ＤＣは正となり、第１電極（オリフィス電極）１の電位がアンテナの電位より低くなるので、プラズマ中の正イオンがこの電位差によってオリフィス電極に向けて加速され、オリフィス電極に形成されたオリフィスに入っていく。オリフィス電極のオリフィスの内部を通過する正イオンは、主として、オリフィスの周壁の固体表面近傍において電子を与えられて中性化されるか、オリフィス電極の表面から放出された電子と衝突して再結合することで中性化されるか、あるいは、オリフィスの内部に残留しているガスとの電荷交換によって中性化されて中性粒子となり、中性粒子ビームを引き出すことが出来る。
【００６９】
同様に、正イオンと負イオンが共存したプラズマにおいて、Ｓａ＞ＳｍのようにすればＶ_ＤＣは負となり、第１電極（オリフィス電極）１の電位がアンテナの電位より高くなるので、プラズマ中の負イオンがこの電位差によってオリフィス電極に向けて加速され、オリフィス電極に形成されたオリフィスに入っていく。オリフィス電極のオリフィスの内部を通過する負イオンは、主として、オリフィスの周壁の固体表面近傍において電子を奪われて中性化され、あるいは、オリフィスの内部に残留しているガスとの電荷交換によって中性化され、中性粒子ビームを引き出すことが出来る。ここで、図７（ｂ）で示すように、高周波電圧の印加と直流電圧の印加の間に、例えば５０μ秒程度の電圧を印加しない負イオン生成時間Ｔを設けてもよい。このようにすると、直流電圧を印加した際にプラズマ中の負イオンの割合が高いので、効率よく大量の負イオンを加速することができる。
【００７０】
また、アンテナの形状は、例えばプラズマ生成室の直径程度の寸法を持つ大口径のらせん状コイルや略円形のループ状コイルの形状であってもよいし、二つ以上のループ状のコイルを並列に接続した形状であってもよい。また、大口径のコイルはインピーダンスが大きくなるので、複数個の小型のアンテナを設置するようにしてもよい。このように、アンテナは、その適正配置によりプラズマ生成室内に均一なプラズマを生成できれば良いので、その構造、形態は問わない。
【００７１】
このように、中性粒子ビームを引き出すことができるので被処理物に対しチャージアップ現象を引き起こさないチャージフリーなビーム源を実現でき、且つプラズマからの放射光を第１電極（オリフィス電極）で遮蔽することのできるビーム源を実現できる。即ち、チャージアップ現象に起因する損傷や放射光による損傷のないダメージフリーなビーム源を実現できる。加えて、ビームを引き出すのに必要となる一対の電極の片方をアンテナが兼ねることで、電極とアンテナの取り合い（相互干渉）を考慮する必要が無い。したがって、プラズマ密度が均一になるようにプラズマ生成室の任意の場所にアンテナを配置することができる。よって、大口径で均一なプラズマの生成と、プラズマからの中性粒子ビームの引き出しの両方が簡単な構成で実現可能である。
【００７２】
また、これまで説明した実施形態では、正イオン、または、負イオンを引き出し、これを中性化して中性粒子ビームとした例を説明したが、第１電極１にオリフィス電極の代わりに例えばグラファイトなどの導電体で形成された薄板グリッド状のグリッド電極を用いることによって、正イオン、または、負イオンを引き出し、これを中性化せずにそのまま正イオンビーム又は負イオンビームとして引き出すこともできる。
【００７３】
次に、本発明に係るビーム処理装置の実施形態について図１０を参照して説明する。この図において、ビーム処理装置のビーム源としては、第１の実施の形態において説明したビーム源を用いた場合を示している。
【００７４】
すなわち、ビーム源は第１電極１、プラズマ生成室４、アンテナ２、高周波電源３、バイアス電源６を備え、さらに、プラズマ生成室４にガスを導入するためのガス導入ポート７、ガス供給管８、ガス供給源９を備えて構成される。
【００７５】
また、第１電極１の下部には、これに隣接して真空チャンバ３０が配置されており、該真空チャンバは、これに接続された真空ポンプ３１により減圧されている。プラズマ生成室４内の圧力は、主としてこの真空チャンバ３０に接続された真空ポンプ３１の排気量と、第１電極１のコンダクタンス、ガス供給源９から供給されるガスの種類やその流量によって決まる。
また、前記真空チャンバ３０内には、ステージ３２が備えられ、ここに被処理物３３を固定する。これにより、ビーム源から大口径で均一なビームを被処理物に照射することができるビーム処理装置を実現できる。
【００７６】
また、前記ビームを中性粒子ビームとすることにより、被処理物３３をチャージフリーに加工することができるから、例えば微細配線に生じる静電気由来の絶縁破壊等のチャージアップ現象に由来する欠陥の発生を最小限に抑えることができ、被処理物の歩留まりを格段に向上させることができる。さらに、被処理物３３に対するプラズマからの放射光を第１電極１で遮蔽することができるので、放射光に由来する欠陥の発生を最小限に抑えることができ、被処理物の歩留まりを格段に向上させることができる。
【００７７】
ここで、ステージ３２は、第１電極１との相対運動が、例えば回転運動や直進運動ができるように構成してもよい。ビーム源から大口径で均一なビームを照射しつつ、ステージ３２を第１電極１に対し適切に相対運動させることにより、被処理物３３を被処理面全体にわたって均一に迅速に処理することができる。
このように、本発明のビーム処理装置によれば、正イオン、負イオン、中性粒子等の各種のビームを大口径で均一に被処理物に照射することができる。また、被処理物に対しチャージアップ現象を引き起こさず（チャージフリー）、且つプラズマからの放射光を遮蔽することのできる、ダメージフリーなビーム処理装置を実現できる。
【００７８】
これまで本発明のビーム源およびビーム処理装置に関する実施形態について説明したが、本発明のビーム源およびビーム処理装置は上述の実施形態に限定されず、その技術的思想の範囲内において種々異なる形態にて実施されてよいことは言うまでもない。
【００７９】
【発明の効果】
上述したように、本発明によれば、正イオン、負イオン、中性粒子等の各種のビームを大口径で均一に被処理物に照射することができると共に、チャージフリー且つダメージフリーを実現するビーム源をコンパクトな構造で提供することができる。さらに、本発明のビーム源を搭載したビーム処理装置により、被処理物の処理が均一で迅速にでき、かつ、歩留まりの高い被処理物の処理を行うことができる。
【図面の簡単な説明】
【図１】本発明の第１の実施形態におけるビーム源の全体構成を示す図である。
【図２】電圧の印加を示す波形図である。
【図３】表面に導電体を備えたアンテナの断面図である。
【図４】本発明の第２の実施形態におけるビーム源の全体構成を示す図である。
【図５】電圧の印加を示す波形図である。
【図６】本発明の第３の実施形態におけるビーム源の全体構成を示す図である。
【図７】電圧の印加を示す波形図である。
【図８】（ａ）は本発明の第４の実施形態におけるビーム源の全体構成を示す図であり、（ｂ）（ｃ）はアンテナの断面図である。
【図９】本発明の第５の実施形態におけるビーム源の全体構成を示す図である。
【図１０】本発明の実施形態におけるビーム処理装置の全体の概略を示す図である。
【図１１】従来のビーム源の全体構成を示す図である。
【図１２】他の従来のビーム源の全体構成を示す図である。
【符号の説明】
１ 第１電極
２ アンテナ
２ｂ 導電体
２ｃ 誘電体
３ 高周波電源
４ プラズマ生成室
６ 直流電源
１２ 誘電体膜
３２ ステージ
３３ 被処理物[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a beam source and a beam processing apparatus used in a manufacturing process of a semiconductor integrated circuit, and in particular, various beams such as high-density positive ions, negative ions, and neutral particles with high directivity from high-density plasma. And a beam processing apparatus.
[0002]
[Prior art]
In recent years, processing patterns have been remarkably miniaturized in the fields of semiconductor integrated circuits, information storage media such as hard disks, and micromachines. In processing in such a field, a processing object is formed or etched by irradiating an energy beam such as an ion beam having high straightness (high directivity) and a relatively large diameter and high density. Technology is drawing attention.
[0003]
As such an energy beam source, one that generates various beams such as positive ions, negative ions, and neutral particles is known. By irradiating various parts such as positive ions, negative ions, and neutral particles from the beam source to any part of the object to be processed, local film formation or etching of the object to be processed, surface modification, Bonding, adhesion, etc. can be performed.
[0004]
Regarding an apparatus that generates various beams such as positive ions, negative ions, and neutral particles, that is, a beam source and a beam processing apparatus using the beam source, for example, Patent Document 1, Patent Document 2, Patent Document 3, It is disclosed in Patent Document 4, Patent Document 5, Patent Document 6, and the like.
[0005]
An example of the basic configuration of the apparatus disclosed in these documents is shown in FIG. In this apparatus, an inductively coupled coil 20 is disposed on the outer periphery of the beam generation chamber 40, and a first electrode 10 made of a conductor such as graphite is disposed at the lower end of the beam generation chamber 40. A second electrode 50 that is also formed of a conductor is disposed above the one electrode 10. An induction magnetic field is generated by flowing a high-frequency current through the coil 20, and the time change of the magnetic field induces an electric field, and electrons are accelerated by the electric field to generate plasma in the beam generation chamber 40. By appropriately applying a voltage between the first electrode 10 and the second electrode 50, various beams such as positive ions, negative ions, and neutral particles can be generated and irradiated to the object X. it can.
I can do it.
[0006]
Further, as a plasma generation source or plasma processing apparatus using plasma, Patent Document 7, Patent Document 8, Patent Document 9, Patent Document 10, Patent Document 11, Patent Document 12, Patent Document 13, Patent Document 14, Patent Document 15 , Etc. are disclosed. Furthermore, another apparatus for generating a neutral particle beam is disclosed in US Pat.
[0007]
[Patent Document 1]
JP 2002-289399 A
[Patent Document 2]
JP 2002-289581 A
[Patent Document 3]
JP 2002-289582 A
[Patent Document 4]
JP 2002-289583 A
[Patent Document 5]
JP 2002-289484 A
[Patent Document 6]
JP 2002-289585 A
[Patent Document 7]
JP-A-10-125497
[Patent Document 8]
Japanese Patent No. 3114873
[Patent Document 9]
JP-T-2001-511945
[Patent Document 10]
Japanese translation of PCT publication No. 2001-507081
[Patent Document 11]
JP-A-8-83696
[Patent Document 12]
JP-A-9-82692
[Patent Document 13]
JP 2001-35697 A
[Patent Document 14]
Japanese Patent No. 3017944
[Patent Document 15]
Japanese Patent No. 3318638
[Patent Document 16]
US Pat. No. 6,331,701
[0008]
[Problems to be solved by the invention]
For mass production of semiconductor integrated circuits, cost reduction, etc., it is essential to increase the diameter of semiconductor integrated circuit manufacturing equipment. However, the conventional beam source has been increased in diameter to make positive ions, negative ions, neutral particles, etc. When trying to generate various beams, there are the following problems.
[0009]
First, in order to obtain a uniform beam with a large area, it is desirable that the density of the plasma, which is the source of the beam, be uniformly distributed in both the radius and the circumferential direction of the beam generation chamber. According to the devices disclosed in Patent Literature 1, Patent Literature 2, Patent Literature 3, Patent Literature 4, Patent Literature 5, Patent Literature 6, and the like, an inductively coupled coil is disposed on the outer periphery of the beam generation chamber. Since the energy supplied from the coil is large at the periphery and small at the center, the density of the generated plasma tends to be uneven in the radial direction as the periphery is dense and the center is sparse. When the aperture is as small as about φ100 mm, sufficient energy is supplied from the coil to the central portion of the beam generation chamber, so that the plasma density hardly becomes uneven. However, if the beam generation chamber is enlarged to increase the diameter, sufficient energy is not supplied from the coil to the central portion of the beam generation chamber, and the plasma density is uneven in the radial direction, leading to extraction of a uniform beam. Is difficult.
[0010]
In order to extract a uniform beam with a large diameter, it is necessary to generate a uniform plasma with a large diameter. In order to obtain a uniform plasma with a large aperture, an inductively coupled coil is covered as disclosed in Patent Literature 7, Patent Literature 8, Patent Literature 9, Patent Literature 10, Patent Literature 11, Patent Literature 12, and the like. It is known to adopt a configuration in which it is arranged to face a workpiece.
[0011]
In these apparatuses, unless an appropriate neutralizing means is provided, charged particles such as positive ions and negative ions are irradiated onto the object to be processed. In a beam source that irradiates an object to be processed with charged particles such as positive ions and negative ions, an insulator cannot be processed (charge-up phenomenon) because charges accumulate on the object to be processed. In addition, since the ion beam diverges due to the space charge effect, it is difficult to perform fine processing.
In order to prevent this, it is also considered to neutralize the charge by pouring electrons into the ion beam. However, although this method can balance the overall charge, there is a local charge imbalance, and it is still difficult to perform fine processing.
[0012]
In addition, when ions are extracted from a plasma source and irradiated on the object to be processed, if the object to be processed is irradiated with radiation such as ultraviolet rays generated from the plasma, the object to be processed is adversely affected. It is necessary to shield radiation light such as ultraviolet rays emitted from.
[0013]
In order to avoid the above problem, a large-diameter beam source that can arbitrarily and uniformly generate various beams such as positive ions, negative ions, and neutral particles has been desired. As a neutral particle beam generator, an inductively coupled coil is arranged opposite to the object to be processed in order to obtain a uniform plasma, and has an appropriate neutralization means. An apparatus having a configuration that blocks the emitted light is disclosed in Patent Document 16. As shown in FIG. 12, the neutral beam generating apparatus includes an RF inductor 93 connected to an RF power source 91 via an impedance matching unit 92, an RF window 94 disposed adjacent to the RF inductor 93, and an RF An RF acceleration means 97 connected to the acceleration circuit 96 and disposed opposite to the RF inductor, and a sub-Debye neutralization grid 112 disposed opposite to the RF acceleration means 97 and set to the ground potential. Plasmas 95 and 99 are generated by supplying RF power from the RF inductor 93. Positive ions are accelerated from the plasma 99 toward the sub-Debye neutralization grid 112 by the potential difference generated between the RF acceleration means 97 and the sub-Debye neutralization grid 112. Grid holes 117 are opened in the sub-Debye neutralization grid 112, and are accelerated when the accelerated positive ions pass through the grid holes 117.
[0014]
However, in order to emit a collimated beam with high neutralization efficiency, a sheath 111 in which a grid hole of the sub-Debye neutralization grid 112 is formed between the plasma 99 and the sub-Debye neutralization grid 112 is used. Therefore, there is a problem in that the manufacturing cost is increased and the materials that can be manufactured are limited. Therefore, although aluminum is adopted in the beam generating apparatus, aluminum is a material unsuitable for a beam source having a large aperture of about 10 inches (column 4, lines 45-48) because of its large thermal deformation. Therefore, it is difficult to obtain a uniform beam with a large aperture using the technique disclosed in Patent Document 16.
[0015]
The present invention has been made in view of such problems of the prior art, and is a beam capable of uniformly irradiating an object to be processed with a large aperture of various beams such as positive ions, negative ions, and neutral particles. It is an object of the present invention to provide a beam processing apparatus for processing an object to be processed using the beam source. In particular, a damage-free beam source that does not cause a charge-up phenomenon on the object to be processed (charge-free) and can shield radiation emitted from plasma, and the object to be processed are processed using these beam sources. An object is to provide a beam processing apparatus.
[0016]
[Means for Solving the Problems]
In order to solve such a problem in the prior art, an aspect of the present invention includes a first electrode disposed in a plasma generation chamber and an inner portion of the plasma generation chamber in order to generate plasma in the plasma generation chamber. An inductively coupled coil disposed to face the first electrode; and a potential difference generating means for generating a potential difference between the first electrode and the inductively coupled coil. The potential difference generating means is a voltage applying means for alternately applying a high frequency voltage and a low frequency voltage to the inductive coupling type coil, and is arranged adjacent to the surface of the inductive coupling type coil. A plate-like dielectric film disposed oppositely, or a dielectric film coated around the inductively coupled coil, wherein the first electrode is an orifice electrode having a plurality of openings; Due to the presence of the dielectric film, Between the inductively coupled coil and the first electrode A self-bias voltage is generated inside the plasma generation chamber. From the generated plasma , The beam source is characterized by extracting a particle beam through the first electrode.
With such a configuration, the coil antenna also serves as one of the pair of electrodes necessary for extracting the particle beam, and it is not necessary to consider the connection (mutual interference) between the electrode and the coil antenna. Therefore, since the coil antenna can be arranged at an arbitrary position so that the plasma density is uniform, various beams such as positive ions, negative ions, and neutral particles can be uniformly generated with a large aperture.
[0017]
In this case, the first electrode and the Inductively coupled coil A potential difference generating means for generating a potential difference between Inductively coupled coil Preferably, it is a voltage applying means for alternately applying a high frequency voltage and a direct current voltage. By applying a DC voltage, ions in the plasma can be accelerated toward the first electrode. In particular, when accelerating negative ions, the negative ions can be generated efficiently and continuously.
[0018]
The first electrode and the Inductively coupled coil A potential difference generating means for generating a potential difference between Inductively coupled coil Is a voltage applying means for alternately applying a high frequency voltage and a low frequency voltage, Inductively coupled coil It is preferable to interpose a dielectric adjacent to the substrate. This coil Due to the presence of the dielectric adjacent to the antenna, a self-bias voltage can be generated and ions can be extracted from the plasma.
[0019]
Also The second One electrode is a means of neutralizing the particle beam Is preferred. With such a configuration, positive ions or negative ions are extracted from the plasma, neutralized, and a neutral beam with high kinetic energy and high linearity in a uniform direction has a large diameter and is uniform. It becomes possible to pull out.
[0020]
Furthermore, another aspect of the present invention is a beam processing apparatus for processing an object to be processed using a beam source, the beam processing apparatus including the beam source configured as described above and facing the first electrode of the beam source. It is characterized by including a stage for supporting a processed object. By selecting any one of the beam sources having the above-mentioned characteristics and configuring the beam processing device, a beam of neutral particles having a large kinetic energy and a uniform direction can be made uniform with a large aperture. It can be pulled out with high straightness. For this reason, the processing speed with respect to a to-be-processed object is high, a uniform process can be performed on the whole surface of a to-be-processed object, and the characteristic according to the usage form of each beam processing apparatus can be exhibited. According to this apparatus, charge-free and damage-free processing can be performed.
[0021]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, a first embodiment of a beam source according to the present invention will be described with reference to FIGS. In addition, in each figure, the same code | symbol is attached | subjected to the member or element which has the same effect | action or function, and the overlapping description is abbreviate | omitted.
[0022]
As shown in FIG. 1, the beam source includes a cylindrical plasma generation chamber 4, a first electrode 1 disposed at the lower end of the plasma generation chamber 4, and a plasma generation chamber that generates plasma in the plasma generation chamber 4. 4 is provided.
The wall surface 7 of the plasma generation chamber 4 is configured using a material selected from quartz glass, ceramic, metal, or the like. The plasma generation chamber 4 is provided with a gas introduction port (not shown) for introducing gas into the plasma generation chamber 4, and this gas introduction port has a gas supply means together with a gas supply pipe (not shown) and a gas supply source (not shown). It is composed. From this gas supply means, SF ₆ , CHF ₃ , CF ₄ , Cl ₂ , Ar, O ₂ , N ₂ , C ₄ F ₈ A gas such as is supplied into the plasma generation chamber 4.
[0023]
The first electrode 1 is an orifice plate (orifice electrode) formed of a conductor such as graphite, and the orifice electrode is set to ground potential. The orifice electrode functions not only as the first electrode but also as a means for neutralizing the particles constituting the beam. Here, the beam source is connected to a vacuum chamber (not shown) via a first electrode (orifice electrode) 1, and the vacuum chamber is decompressed by a vacuum pump connected thereto. The pressure in the plasma generation chamber 4 is determined mainly by the displacement of a vacuum pump connected to the vacuum chamber, the conductance of the orifice electrode, the type of gas supplied, and the flow rate thereof.
[0024]
The antenna 2 is, for example, an inductive coupling type coil whose surface is disposed at the upper end inside the plasma generation chamber 4 so as to face the first electrode 1. This antenna is connected to the high frequency power source 3 via a matching box (not shown), and for example, a high frequency voltage of 13.56 MHz is applied to the antenna. These antenna, matching box, and high-frequency power source 3 constitute a plasma generating means. That is, an induction magnetic field is generated by applying a high-frequency current to the antenna, and the time change of the magnetic field induces an electric field, and electrons are accelerated by the electric field to generate plasma. In this way, the plasma can be generated uniformly in the plasma generation chamber by arranging the antenna for generating the plasma at an appropriate position in the plasma generation chamber.
[0025]
Here, the plasma formed when the high frequency voltage supplied from the high frequency power supply 3 is continuously applied to the antenna as shown in FIG. 2A is a plasma mainly composed of positive ions and heated electrons. is there. On the other hand, for example, when a series of operations of alternately applying a high-frequency voltage supplied from the high-frequency power source 3 to the antenna for 10 μsec as shown in FIG. It can be generated continuously, and a plasma in which positive ions and negative ions coexist can be generated. Here, the negative ions are not positively ionized during the application of the high-frequency voltage and remain neutral, while the electrons heated during the application of the high-frequency voltage stop applying the high-frequency voltage. It is produced by collision and mainly causing dissociative adhesion.
[0026]
As described above, by the method of supplying the high frequency voltage from the high frequency power source 3, two types of plasma, that is, plasma mainly composed of positive ions and heated electrons and plasma in which positive ions and negative ions coexist can be generated. it can. In addition, the form of this antenna may have a form of a water cooling pipe for cooling itself. Since the antenna 2 and the high-frequency power source 3 are connected in series with a DC bias power source 6 that is a potential difference generating means, the potential of the antenna 2 is relative to the potential of the first electrode 1 (ground potential). A difference is generated by a potential given by the sum of the potential of the high-frequency power source 3 and the potential of the bias power source 6 as shown in FIGS. Here, since the surface of the antenna 2 is a conductor, a beam can be extracted from the plasma generated by the antenna 2 by this potential difference.
[0027]
For example, when the potential of the first electrode (orifice electrode) 1 is lower than the potential of the antenna in a plasma mainly composed of positive ions and heated electrons and a plasma in which positive ions and negative ions coexist (FIG. 2 (c) )), Positive ions in the plasma are accelerated toward the orifice electrode by this potential difference, and enter the orifice formed in the orifice electrode. Positive ions passing through the orifice of the orifice electrode are neutralized mainly by giving electrons near the solid surface of the peripheral wall of the orifice, or colliding with electrons emitted from the surface of the orifice electrode and recombining. By doing so, it is neutralized or neutralized by charge exchange with the gas remaining inside the orifice to become neutral particles, and a neutral particle beam can be extracted.
[0028]
Similarly, in a plasma in which positive ions and negative ions coexist, when the potential of the first electrode (orifice electrode) 1 is higher than the potential of the antenna (FIG. 2 (d)), the negative ions in the plasma become orifices due to this potential difference. It accelerates towards the electrode and enters the orifice formed in the orifice electrode. Negative ions that pass through the orifice of the orifice electrode are neutralized mainly by depriving electrons near the solid surface of the peripheral wall of the orifice, or by charge exchange with the gas remaining inside the orifice. And neutral beam can be extracted.
[0029]
As shown in FIG. 3, in the antenna 2, the copper pipe 2a may be coated with another conductor 2b, such as graphite. According to this, since the copper pipe 2a can be protected from plasma, it is possible to prevent copper impurities from being mixed into the particle beam.
[0030]
The shape of the antenna 2 may be, for example, a large-diameter spiral coil having a size approximately equal to the diameter of the plasma generation chamber or a substantially circular loop coil, or two or more loop coils. The shape connected in parallel may be sufficient. In addition, since a large-diameter coil has a large impedance, a plurality of small antennas may be installed. As described above, the antenna is not limited in its structure and configuration as long as it can generate uniform plasma in the plasma generation chamber by its proper arrangement.
[0031]
In this way, since the neutral particle beam can be extracted, a charge-free beam source that does not cause a charge-up phenomenon on the object to be processed can be realized, and the emitted light from the plasma can be emitted from the first electrode (orifice electrode). A beam source that can be shielded with can be realized. That is, it is possible to realize a damage-free beam source free from damage caused by the charge-up phenomenon and damage caused by radiated light. In addition, since the antenna also serves as one of the pair of electrodes necessary for extracting the beam, it is no longer necessary to consider the contact between the electrode and the antenna (mutual interference). Therefore, the antenna 2 can be disposed at an arbitrary location in the plasma generation chamber so that the plasma density is uniform. Therefore, both generation of a uniform plasma with a large diameter and extraction of a neutral particle beam from the plasma can be realized with a simple configuration.
[0032]
Next, a second embodiment of the beam source according to the present invention will be described with reference to FIGS. In addition, the same code | symbol is attached | subjected to the member or element which has the same effect | action or function as the member or element in the above-mentioned 1st Embodiment, and the part which is not demonstrated in particular is the same as that of 1st Embodiment.
[0033]
As shown in FIG. 4, the beam source includes a cylindrical plasma generation chamber 4, a first electrode 1 disposed at the lower end of the plasma generation chamber 4, and a plasma generation chamber that generates plasma in the plasma generation chamber 4. 4 is provided with an antenna 2 arranged in the interior.
The wall surface of the plasma generation chamber 4 is selected from quartz glass, ceramic, metal, or the like. The plasma generation chamber 4 is provided with a gas introduction port (not shown) for introducing gas into the plasma generation chamber 4, and this gas introduction port has a gas supply means together with a gas supply pipe (not shown) and a gas supply source (not shown). It is composed. From this gas supply means, SF ₆ , CHF ₃ , CF ₄ , Cl ₂ , Ar, O ₂ , N ₂ , C ₄ F ₈ A gas such as is supplied into the plasma generation chamber 4. The first electrode 1 is an orifice plate (orifice electrode) formed of a conductor such as graphite, and the orifice electrode is set to ground potential. The orifice electrode functions not only as the first electrode but also as a means for neutralizing the particles constituting the beam.
[0034]
Here, the beam source is connected to a vacuum chamber (not shown) via a first electrode (orifice electrode) 1, and the vacuum chamber is decompressed by a vacuum pump connected thereto. The pressure in the plasma generation chamber 4 is determined mainly by the displacement of a vacuum pump connected to the vacuum chamber, the conductance of the orifice electrode, the type of gas supplied, and the flow rate thereof.
[0035]
The antenna 2 is, for example, an inductive coupling type coil whose surface is disposed at the upper end inside the plasma generation chamber 4 so as to face the first electrode 1. The antenna 2 is connected to a high frequency power source 3 via a matching box (not shown), and a high frequency voltage of 13.56 MHz, for example, is applied to the antenna. The antenna 2, the matching box, and the high frequency power source 3 constitute a plasma generating means. That is, an induction magnetic field is generated by applying a high-frequency current to the antenna, and the time change of the magnetic field induces an electric field, and electrons are accelerated by the electric field to generate plasma. In this way, the plasma can be generated uniformly in the plasma generation chamber by arranging the antenna for generating the plasma at an appropriate position in the plasma generation chamber.
[0036]
Here, as described in the first embodiment, by the method of supplying a high frequency voltage from the high frequency power source 3, a plasma mainly composed of positive ions and heated electrons and a plasma in which positive ions and negative ions coexist are used. Two types of plasma can be generated. In addition, the form of this antenna may have a form of a water cooling pipe for cooling itself.
[0037]
The antenna 2 is also connected to a DC bias power source 6. This bias power source 6 constitutes a voltage applying means together with the high frequency power source 3, and can apply a high frequency voltage from the high frequency power source 3 and a DC voltage from the bias power source 6 alternately to the antenna as shown in FIG. . Here, the time during which the DC voltage is applied is sufficiently shorter than the time when the plasma is extinguished. Then, since the surface of the antenna is a conductor, it is possible to repeat a series of operations of generating a plasma by applying a high frequency voltage and then extracting a beam by applying a DC voltage.
[0038]
For example, in a plasma mainly composed of positive ions and heated electrons, and in a plasma in which positive ions and negative ions coexist, the DC voltage applied to the antenna by the bias power source 6 is set to a positive bias voltage as shown by the solid line in FIG. In other words, if the potential of the first electrode (orifice electrode) 1 is made lower than the potential of the antenna 2, positive ions in the plasma are accelerated toward the orifice electrode by this potential difference and enter the orifice formed in the orifice electrode. To go. The positive ions passing through the orifice of the orifice electrode 1 are neutralized mainly by giving electrons near the solid surface of the peripheral wall of the orifice, or colliding with electrons emitted from the surface of the orifice electrode and regenerating. Neutralized by coupling, or neutralized by charge exchange with the gas remaining inside the orifice to become neutral particles, and a neutral particle beam can be extracted.
[0039]
Similarly, in a plasma in which positive ions and negative ions coexist, when a negative bias voltage is applied to the antenna by the bias power source 6 as shown by a broken line in FIG. 5, the potential of the first electrode (orifice electrode) 1 is set to the antenna. Since it becomes higher than the potential, negative ions in the plasma are accelerated toward the orifice electrode by this potential difference, and enter the orifice formed in the orifice electrode. Negative ions that pass through the orifice of the orifice electrode are neutralized mainly by depriving electrons near the solid surface of the peripheral wall of the orifice, or by charge exchange with the gas remaining inside the orifice. And neutral beam can be extracted. Here, as shown by a two-dot chain line in FIG. 5, a negative ion generation time in which a voltage of about 50 μs, for example, is not applied may be provided between the application of the high frequency voltage and the application of the DC voltage. In this way, when a direct current voltage is applied, the ratio of negative ions in the plasma is high, so that a large amount of negative ions can be efficiently accelerated.
[0040]
As in the first embodiment, the antenna 2 may be coated with a copper pipe with another conductor, such as graphite, as shown in FIG. According to this, since the copper pipe can be protected from plasma, it is possible to prevent copper impurities from being mixed into the beam.
Further, the shape of the antenna may be, for example, a large-diameter spiral coil having a size approximately equal to the diameter of the plasma generation chamber or a substantially circular loop-shaped coil, or two or more loop-shaped coils are arranged in parallel. The shape connected to may be sufficient. In addition, since a large-diameter coil has a large impedance, a plurality of small antennas may be installed. As described above, the antenna is not limited in its structure and configuration as long as it can generate uniform plasma in the plasma generation chamber by its proper arrangement.
[0041]
In this way, since the neutral particle beam can be extracted, a charge-free beam source that does not cause a charge-up phenomenon to the object to be processed can be realized, and the radiation light from the plasma can be emitted from the first electrode (orifice electrode) 1. A beam source that can be shielded can be realized. That is, it is possible to realize a damage-free beam source free from damage caused by the charge-up phenomenon and damage caused by radiated light. In addition, since the antenna also serves as one of the pair of electrodes necessary for extracting the beam, it is no longer necessary to consider the contact between the electrode and the antenna (mutual interference). Therefore, the antenna can be arranged at an arbitrary location in the plasma generation chamber so that the plasma density is uniform. Therefore, both the generation of a uniform plasma with a large diameter and the extraction of the neutral particle beam from the plasma can be realized with a simple configuration.
[0042]
Next, a third embodiment of the beam source according to the present invention will be described with reference to FIGS. In addition, the same code | symbol is attached | subjected to the member or element which has the same effect | action or function as the member or element in the above-mentioned 1st Embodiment, and the part which is not demonstrated in particular is the same as that of 1st Embodiment.
As shown in FIG. 6, the beam source includes a cylindrical plasma generation chamber 4, a first electrode 1 disposed at the lower end of the plasma generation chamber 4, and an antenna 2 that generates plasma in the plasma generation chamber 4. And a dielectric film 12 disposed adjacent to the antenna between the antenna and the first electrode.
[0043]
The wall surface of the plasma generation chamber 4 is made of a material selected from quartz glass, ceramic, metal and the like. The plasma generation chamber 4 is provided with a gas introduction port (not shown) for introducing gas into the plasma generation chamber 4, and this gas introduction port has a gas supply means together with a gas supply pipe (not shown) and a gas supply source (not shown). It is composed. From this gas supply means, SF ₆ , CHF ₃ , CF ₄ , Cl ₂ , Ar, O ₂ , N ₂ , C ₄ F ₈ A gas such as is supplied into the plasma generation chamber 4.
The first electrode 1 is an orifice plate (orifice electrode) formed of a conductor such as graphite, and the orifice electrode is set to ground potential. The orifice electrode functions not only as the first electrode but also as a means for neutralizing the particles constituting the beam.
[0044]
Here, the beam source is connected to a vacuum chamber (not shown) via a first electrode (orifice electrode) 1, and the vacuum chamber is decompressed by a vacuum pump connected thereto. The pressure in the plasma generation chamber 4 is determined mainly by the displacement of a vacuum pump connected to the vacuum chamber, the conductance of the orifice electrode, the type of gas supplied, and the flow rate thereof.
[0045]
The antenna 2 is, for example, an inductively coupled coil disposed at the upper end inside the plasma generation chamber 4 so as to face the first electrode 1. This antenna is connected to the high frequency power source 3 via a matching box (not shown), and for example, a high frequency voltage of 13.56 MHz is applied to the antenna. These antenna, matching box, and high-frequency power source 3 constitute a plasma generating means. That is, an induction magnetic field is generated by passing a high-frequency current through the antenna 2, and the time change of the magnetic field induces an electric field, and electrons are accelerated by the electric field to generate plasma. In this way, the plasma can be generated uniformly in the plasma generation chamber by arranging the antenna for generating the plasma at an appropriate position in the plasma generation chamber.
[0046]
Here, as described in the first embodiment, by the method of supplying a high frequency voltage from the high frequency power source 3, a plasma mainly composed of positive ions and heated electrons and a plasma in which positive ions and negative ions coexist are used. Two types of plasma can be generated. In addition, the form of this antenna may have a form of a water cooling pipe for cooling itself.
[0047]
The antenna 2 is also connected to a low frequency bias power source 6 having a frequency of 600 kHz, for example. This bias power source 6 constitutes a voltage applying means together with the high frequency power source 3, and as shown in FIG. 7A, a high frequency voltage from the high frequency power source 3 and a low frequency voltage from the bias power source 6 are alternately applied to the antenna. can do. Here, the time during which the low frequency voltage is applied is sufficiently shorter than the time when the plasma is extinguished. Then, due to the presence of the dielectric film 12 disposed adjacent to the antenna, a self-bias voltage is generated between the antenna 2 and the first electrode 1 when a low frequency voltage is applied, and the beam can be extracted. . Therefore, after a plasma is generated by applying a high frequency voltage, a series of operations of extracting a beam by applying a low frequency voltage can be repeated.
[0048]
Here, the DC component V of the self-bias voltage _DC This is considered to be simply expressed by the equation (1) depending on the area Sa of the first electrode 1, the area Sk of the dielectric film, and the amplitude V of the voltage of the bias power source 6.
[Expression 1]

Here, α is a coefficient.
[0049]
For example, in a plasma mainly composed of positive ions and heated electrons and in a plasma in which positive ions and negative ions coexist, if Sa <αSk, V < _DC Since the potential of the first electrode (orifice electrode) 1 becomes lower than the potential of the antenna, positive ions in the plasma are accelerated toward the orifice electrode by this potential difference and enter the orifice formed in the orifice electrode. Go. Positive ions passing through the orifice of the orifice electrode are neutralized mainly by giving electrons near the solid surface of the peripheral wall of the orifice, or colliding with electrons emitted from the surface of the orifice electrode and recombining. By doing so, it is neutralized or neutralized by charge exchange with the gas remaining inside the orifice to become neutral particles, and a neutral particle beam can be extracted.
[0050]
Similarly, in a plasma in which positive ions and negative ions coexist, if Sa> αSk, V _DC Becomes negative, and the potential of the first electrode (orifice electrode) 1 becomes higher than the potential of the antenna. Therefore, negative ions in the plasma are accelerated toward the orifice electrode by this potential difference and enter the orifice formed in the orifice electrode. Go. Negative ions that pass through the orifice of the orifice electrode are neutralized mainly by depriving electrons near the solid surface of the peripheral wall of the orifice, or by charge exchange with the gas remaining inside the orifice. And neutral beam can be extracted. Here, as shown in FIG. 7B, a negative ion generation time T in which a voltage of, for example, about 50 μs is not applied may be provided between the application of the high frequency voltage and the application of the DC voltage. In this way, when a direct current voltage is applied, the ratio of negative ions in the plasma is high, so that a large amount of negative ions can be efficiently accelerated.
[0051]
Further, the shape of the antenna may be, for example, a large-diameter spiral coil having a size approximately equal to the diameter of the plasma generation chamber or a substantially circular loop-shaped coil, or two or more loop-shaped coils are arranged in parallel. The shape connected to may be sufficient. In addition, since a large-diameter coil has a large impedance, a plurality of small antennas may be installed. As described above, the antenna is not limited in its structure and configuration as long as it can generate uniform plasma in the plasma generation chamber by its proper arrangement.
[0052]
In this way, a neutral particle beam can be extracted, so that a charge-free beam source that does not cause a charge-up phenomenon on the object to be processed can be realized, and radiation light from the plasma is shielded by the first electrode (orifice electrode). The beam source that can do was realized. That is, it is possible to realize a damage-free beam source free from damage caused by the charge-up phenomenon or damage caused by the emitted light. In addition, since the antenna also serves as one of the pair of electrodes necessary for extracting the beam, it is not necessary to consider the connection between the electrodes and the antenna (mutual interference). Therefore, the antenna can be arranged at an arbitrary location in the plasma generation chamber so that the plasma density is uniform. Therefore, both generation of a uniform plasma with a large diameter and extraction of a neutral particle beam from the plasma can be realized with a simple configuration.
[0053]
Next, a fourth embodiment of the beam source according to the present invention will be described with reference to FIG. In addition, the same code | symbol is attached | subjected to the member or element which has the same effect | action or function as the member or element in the above-mentioned 1st Embodiment, and the part which is not demonstrated in particular is the same as that of 1st Embodiment.
As shown in FIG. 8A, this beam source generates a plasma in a cylindrical plasma generation chamber 4, a first electrode 1 disposed at the lower end of the plasma generation chamber 4, and the plasma generation chamber 4. An antenna 2 disposed in the plasma generation chamber 4 is provided.
[0054]
The wall surface of the plasma generation chamber 4 is made of a material selected from quartz glass, ceramic, metal and the like. The plasma generation chamber 4 is provided with a gas introduction port (not shown) for introducing gas into the plasma generation chamber 4, and this gas introduction port has a gas supply means together with a gas supply pipe (not shown) and a gas supply source (not shown). It is composed. From this gas supply means, SF ₆ , CHF ₃ , CF ₄ , Cl ₂ , Ar, O ₂ , N ₂ , C ₄ F ₈ A gas such as is supplied into the plasma generation chamber 4.
The first electrode 1 is an orifice plate (orifice electrode) formed of a conductor such as graphite, and the orifice electrode is set to ground potential. The orifice electrode functions not only as the first electrode but also as a means for neutralizing the particles constituting the beam.
[0055]
Here, the beam source is connected to a vacuum chamber (not shown) via a first electrode (orifice electrode) 1, and the vacuum chamber is decompressed by a vacuum pump connected thereto. The pressure in the plasma generation chamber 4 is determined mainly by the displacement of a vacuum pump connected to the vacuum chamber, the conductance of the orifice electrode, the type of gas supplied, and the flow rate thereof.
[0056]
The antenna 2 is, for example, an inductively coupled coil disposed at the upper end inside the plasma generation chamber 4 so as to face the first electrode 1, and the surface is covered with a dielectric 9. The antenna 2 may be in the form of a water-cooled pipe for cooling itself. The antenna 2 may have a form in which, for example, as shown in FIG. 8 (b), a copper pipe 2a is covered with one or more dielectric films 2c such as quartz, or as shown in FIG. 8 (c). The copper pipe 2a may be covered with a dielectric tube 2e through a hollow portion 2d such as gas or vacuum.
[0057]
This antenna is connected to the high frequency power source 3 via a matching box (not shown), and for example, a high frequency voltage of 13.56 MHz is applied to the antenna. These antenna, matching box, and high-frequency power source 3 constitute a plasma generating means. That is, an induction magnetic field is generated by applying a high-frequency current to the antenna, and the time change of the magnetic field induces an electric field, and electrons are accelerated by the electric field to generate plasma. In this way, the plasma can be uniformly generated in the plasma generation chamber by arranging the antenna 2 for generating the plasma at an appropriate position in the plasma generation chamber.
Here, as described in the first embodiment, by the method of supplying a high frequency voltage from the high frequency power source 3, a plasma mainly composed of positive ions and heated electrons and a plasma in which positive ions and negative ions coexist are used. Two types of plasma can be generated.
[0058]
The antenna 2 is also connected to a low frequency bias power source 6 having a frequency of 600 kHz, for example. This bias power source 6 constitutes a voltage applying means together with the high frequency power source 3, and as shown in FIG. 7A, a high frequency voltage from the high frequency power source 3 and a low frequency voltage from the bias power source 6 are alternately applied to the antenna. can do. Here, the time during which the low frequency voltage is applied is sufficiently shorter than the time when the plasma is extinguished. Then, since the surface of the antenna is covered with a dielectric, a self-bias voltage is generated between the antenna 2 and the first electrode 1 when a low frequency voltage is applied, and the beam can be extracted. Therefore, after a plasma is generated by applying a high frequency voltage, a series of operations of extracting a beam by applying a low frequency voltage can be repeated.
[0059]
Here, the DC component V of the self-bias voltage _DC Is considered to be simply given by the equation (2) depending on the area Sa of the first electrode 1, the surface area S1 of the dielectric covering the antenna, and the amplitude V of the voltage of the bias power source 6.
[Expression 2]

[0060]
For example, in a plasma mainly composed of positive ions and heated electrons and in a plasma in which positive ions and negative ions coexist, if Sa <Sl, V < _DC Since the potential of the first electrode (orifice electrode) 1 becomes lower than the potential of the antenna, positive ions in the plasma are accelerated toward the orifice electrode by this potential difference and enter the orifice formed in the orifice electrode. Go. Positive ions passing through the orifice of the orifice electrode are neutralized mainly by giving electrons near the solid surface of the peripheral wall of the orifice, or colliding with electrons emitted from the surface of the orifice electrode and recombining. By doing so, it is neutralized or neutralized by charge exchange with the gas remaining inside the orifice to become neutral particles, and a neutral particle beam can be extracted.
[0061]
Similarly, if Sa> Sl in a plasma in which positive ions and negative ions coexist, V _DC Becomes negative, and the potential of the first electrode (orifice electrode) 1 becomes higher than the potential of the antenna. Therefore, negative ions in the plasma are accelerated toward the orifice electrode by this potential difference and enter the orifice formed in the orifice electrode. Go. Negative ions that pass through the orifice of the orifice electrode are neutralized mainly by depriving electrons near the solid surface of the peripheral wall of the orifice, or by charge exchange with the gas remaining inside the orifice. And neutral beam can be extracted. Here, as shown in FIG. 7B, a negative ion generation time T in which a voltage of, for example, about 50 μs is not applied may be provided between the application of the high frequency voltage and the application of the DC voltage. In this way, when a direct current voltage is applied, the ratio of negative ions in the plasma is high, so that a large amount of negative ions can be efficiently accelerated.
[0062]
Further, the shape of the antenna may be, for example, a large-diameter spiral coil having a size approximately equal to the diameter of the plasma generation chamber or a substantially circular loop-shaped coil, or two or more loop-shaped coils are arranged in parallel. The shape connected to may be sufficient. In addition, since a large-diameter coil has a large impedance, a plurality of small antennas may be installed. As described above, the antenna is not limited in its structure and configuration as long as it can generate uniform plasma in the plasma generation chamber by its proper arrangement.
[0063]
In this way, a neutral particle beam can be extracted, so that a charge-free beam source that does not cause a charge-up phenomenon on the object to be processed can be realized, and radiation light from the plasma is shielded by the first electrode (orifice electrode). Can be realized. That is, it is possible to realize a damage-free beam source free from damage caused by the charge-up phenomenon or damage caused by the emitted light. In addition, since the antenna also serves as one of the pair of electrodes necessary for extracting the beam, it is not necessary to consider the connection between the electrode and the antenna. Therefore, since the antenna can be placed anywhere in the plasma generation chamber so that the plasma density is uniform, both large-diameter and uniform plasma generation and neutral particle beam extraction from the plasma are easy. It can be realized with a simple configuration.
[0064]
Next, a fifth embodiment of the beam source according to the present invention will be described with reference to FIG. In addition, the same code | symbol is attached | subjected to the member or element which has the same effect | action or function as the member or element in the above-mentioned 1st Embodiment, and the part which is not demonstrated in particular is the same as that of 1st Embodiment.
As shown in FIG. 9, the beam source includes a cylindrical plasma generation chamber 4, a first electrode 1 disposed at the lower end of the plasma generation chamber 4, and the plasma that generates plasma in the plasma generation chamber 4. And an antenna 2 disposed in the generation chamber 4.
[0065]
The wall surface of the plasma generation chamber 4 is made of a material selected from quartz glass, ceramic, metal and the like. The plasma generation chamber 4 is provided with a gas introduction port (not shown) for introducing gas into the plasma generation chamber 4, and this gas introduction port has a gas supply means together with a gas supply pipe (not shown) and a gas supply source (not shown). It is composed. From this gas supply means, SF ₆ , CHF ₃ , CF ₄ , Cl ₂ , Ar, O ₂ , N ₂ , C ₄ F ₈ A gas such as is supplied into the plasma generation chamber 4.
The first electrode 1 is an orifice plate (orifice electrode) formed of a conductor such as graphite, and the orifice electrode is set to ground potential. The orifice electrode functions not only as the first electrode but also as a means for neutralizing the particles constituting the beam.
Here, the beam source is connected to a vacuum chamber (not shown) via a first electrode (orifice electrode) 1, and the vacuum chamber is decompressed by a vacuum pump connected thereto. The pressure in the plasma generation chamber 4 is determined mainly by the displacement of a vacuum pump connected to the vacuum chamber, the conductance of the orifice electrode, the type of gas supplied, and the flow rate thereof. The antenna 2 is, for example, an inductively coupled coil disposed at the upper end inside the plasma generation chamber 4 so as to face the first electrode 1. The antenna 2 may be in the form of a water-cooled pipe for cooling itself.
[0066]
The antenna 2 is connected to a high frequency power source 3 via a matching box (not shown), and a high frequency voltage of 13.56 MHz, for example, is applied to the antenna. The antenna 2, the matching box, and the high frequency power source 3 constitute a plasma generating means. That is, an induction magnetic field is generated by applying a high-frequency current to the antenna, and the time change of the magnetic field induces an electric field, and electrons are accelerated by the electric field to generate plasma. In this way, the plasma can be generated uniformly in the plasma generation chamber by arranging the antenna for generating the plasma at an appropriate position in the plasma generation chamber. Here, as described in the first embodiment, by the method of supplying a high frequency voltage from the high frequency power source 3, a plasma mainly composed of positive ions and heated electrons and a plasma in which positive ions and negative ions coexist are used. Two types of plasma can be generated.
[0067]
The antenna 2 is connected to a low frequency bias power source 6 having a frequency of 600 kHz, for example, via a dielectric 6c such as a capacitor. The bias power source 6 constitutes a voltage applying means together with the high frequency power source 3, and as shown in FIG. 7A, the high frequency voltage from the high frequency power source 3 and the low frequency voltage from the bias power source 6 are alternately supplied to the antenna 2. Can be applied. Here, the time during which the low frequency voltage is applied is sufficiently shorter than the time when the plasma is extinguished. Then, since the antenna is connected to the bias power source 6 via the dielectric, a self-bias voltage is generated between the antenna 2 and the first electrode 1 when a low frequency voltage is applied, and the beam can be extracted. it can. Therefore, after a plasma is generated by applying a high frequency voltage, a series of operations of extracting a beam by applying a low frequency voltage can be repeated.
Here, the DC component V of the self-bias voltage _DC Is considered to be simply given by equation (3) depending on the area Sa of the first electrode 1, the surface area Sm of the antenna 2, and the amplitude V of the voltage of the bias power source 6.
[Equation 3]

[0068]
For example, in a plasma mainly composed of positive ions and heated electrons and a plasma in which positive ions and negative ions coexist, if Sa <Sm, V < _DC Since the potential of the first electrode (orifice electrode) 1 becomes lower than the potential of the antenna, positive ions in the plasma are accelerated toward the orifice electrode by this potential difference and enter the orifice formed in the orifice electrode. Go. Positive ions passing through the orifice of the orifice electrode are neutralized mainly by giving electrons near the solid surface of the peripheral wall of the orifice, or colliding with electrons emitted from the surface of the orifice electrode and recombining. By doing so, it is neutralized or neutralized by charge exchange with the gas remaining inside the orifice to become neutral particles, and a neutral particle beam can be extracted.
[0069]
Similarly, if Sa> Sm in a plasma in which positive ions and negative ions coexist, V _DC Becomes negative, and the potential of the first electrode (orifice electrode) 1 becomes higher than the potential of the antenna. Therefore, negative ions in the plasma are accelerated toward the orifice electrode by this potential difference and enter the orifice formed in the orifice electrode. Go. Negative ions that pass through the orifice of the orifice electrode are neutralized mainly by depriving electrons near the solid surface of the peripheral wall of the orifice, or by charge exchange with the gas remaining inside the orifice. And neutral beam can be extracted. Here, as shown in FIG. 7B, a negative ion generation time T in which a voltage of, for example, about 50 μs is not applied may be provided between the application of the high frequency voltage and the application of the DC voltage. In this way, when a direct current voltage is applied, the ratio of negative ions in the plasma is high, so that a large amount of negative ions can be efficiently accelerated.
[0070]
Further, the shape of the antenna may be, for example, a large-diameter spiral coil having a size approximately equal to the diameter of the plasma generation chamber or a substantially circular loop-shaped coil, or two or more loop-shaped coils are arranged in parallel. The shape connected to may be sufficient. In addition, since a large-diameter coil has a large impedance, a plurality of small antennas may be installed. As described above, the antenna is not limited in its structure and configuration as long as it can generate uniform plasma in the plasma generation chamber by its proper arrangement.
[0071]
In this way, a neutral particle beam can be extracted, so that a charge-free beam source that does not cause a charge-up phenomenon on the object to be processed can be realized, and radiation light from the plasma is shielded by the first electrode (orifice electrode). Can be realized. That is, it is possible to realize a damage-free beam source free from damage caused by the charge-up phenomenon or damage caused by the emitted light. In addition, since the antenna also serves as one of the pair of electrodes necessary for extracting the beam, it is not necessary to consider the connection between the electrode and the antenna (mutual interference). Therefore, the antenna can be arranged at an arbitrary location in the plasma generation chamber so that the plasma density is uniform. Therefore, both generation of a uniform plasma with a large diameter and extraction of a neutral particle beam from the plasma can be realized with a simple configuration.
[0072]
In the embodiments described so far, an example in which positive ions or negative ions are extracted and neutralized to form a neutral particle beam has been described. However, instead of the orifice electrode, for example, graphite is used as the first electrode 1. By using a grid electrode in the form of a thin plate formed of a conductor such as a positive electrode or a negative ion, it can be extracted as a positive ion beam or a negative ion beam as it is without being neutralized. .
[0073]
Next, an embodiment of a beam processing apparatus according to the present invention will be described with reference to FIG. In this figure, the beam source described in the first embodiment is used as the beam source of the beam processing apparatus.
[0074]
That is, the beam source includes the first electrode 1, the plasma generation chamber 4, the antenna 2, the high frequency power source 3, and the bias power source 6, and further includes a gas introduction port 7 for introducing gas into the plasma generation chamber 4, and a gas supply pipe 8. A gas supply source 9 is provided.
[0075]
A vacuum chamber 30 is disposed adjacent to the lower portion of the first electrode 1, and the vacuum chamber is decompressed by a vacuum pump 31 connected thereto. The pressure in the plasma generation chamber 4 is mainly determined by the exhaust amount of the vacuum pump 31 connected to the vacuum chamber 30, the conductance of the first electrode 1, the type of gas supplied from the gas supply source 9, and the flow rate thereof.
Further, a stage 32 is provided in the vacuum chamber 30, and an object 33 to be processed is fixed thereto. Thereby, the beam processing apparatus which can irradiate a to-be-processed object with a large diameter and uniform beam from a beam source is realizable.
[0076]
Moreover, since the workpiece 33 can be processed in a charge-free manner by using a neutral particle beam as the beam, generation of defects due to a charge-up phenomenon such as dielectric breakdown caused by static electricity generated in a fine wiring, for example. Can be minimized, and the yield of objects to be processed can be significantly improved. Furthermore, since the first electrode 1 can shield the radiated light from the plasma with respect to the workpiece 33, the generation of defects derived from the radiated light can be minimized, and the yield of the workpiece is markedly increased. Can be improved.
[0077]
Here, the stage 32 may be configured such that the relative motion with the first electrode 1 can be, for example, rotational motion or linear motion. The target object 33 can be uniformly and rapidly processed over the entire surface to be processed by appropriately moving the stage 32 relative to the first electrode 1 while irradiating a uniform beam with a large diameter from the beam source. .
As described above, according to the beam processing apparatus of the present invention, various types of beams such as positive ions, negative ions, and neutral particles can be uniformly irradiated on a workpiece with a large aperture. Further, it is possible to realize a damage-free beam processing apparatus that does not cause a charge-up phenomenon on the object to be processed (charge-free) and can shield radiation emitted from plasma.
[0078]
Although the embodiments related to the beam source and the beam processing apparatus of the present invention have been described so far, the beam source and the beam processing apparatus of the present invention are not limited to the above-described embodiments, and can be variously modified within the scope of the technical idea. Needless to say, it may be implemented.
[0079]
【The invention's effect】
As described above, according to the present invention, various kinds of beams such as positive ions, negative ions, and neutral particles can be uniformly irradiated on a workpiece with a large aperture, and charge-free and damage-free can be realized. The beam source can be provided with a compact structure. Furthermore, the beam processing apparatus equipped with the beam source according to the present invention can perform processing of the processing object uniformly and quickly, and can process the processing object with a high yield.
[Brief description of the drawings]
FIG. 1 is a diagram showing an overall configuration of a beam source according to a first embodiment of the present invention.
FIG. 2 is a waveform diagram showing voltage application.
FIG. 3 is a cross-sectional view of an antenna having a conductor on its surface.
FIG. 4 is a diagram showing an overall configuration of a beam source according to a second embodiment of the present invention.
FIG. 5 is a waveform diagram showing application of voltage.
FIG. 6 is a diagram showing an overall configuration of a beam source according to a third embodiment of the present invention.
FIG. 7 is a waveform diagram showing application of voltage.
FIGS. 8A and 8B are diagrams showing an overall configuration of a beam source according to a fourth embodiment of the present invention, and FIGS. 8B and 8C are cross-sectional views of an antenna.
FIG. 9 is a diagram showing an overall configuration of a beam source according to a fifth embodiment of the present invention.
FIG. 10 is a diagram showing an overall outline of a beam processing apparatus in an embodiment of the present invention.
FIG. 11 is a diagram showing an overall configuration of a conventional beam source.
FIG. 12 is a diagram showing an overall configuration of another conventional beam source.
[Explanation of symbols]
1 First electrode
2 Antenna
2b Conductor
2c dielectric
3 High frequency power supply
4 Plasma generation chamber
6 DC power supply
12 Dielectric film
32 stages
33 Workpiece

Claims (2)

A first electrode disposed in the plasma generation chamber;
An inductively coupled coil disposed in the plasma generation chamber opposite to the first electrode to generate plasma in the plasma generation chamber;
A potential difference generating means for generating a potential difference between the first electrode and the inductively coupled coil;
The potential difference generating means is a voltage applying means for alternately applying a high frequency voltage and a low frequency voltage to the inductively coupled coil;
A plate-like dielectric film disposed adjacent to the surface of the inductively coupled coil and opposed to the first electrode, or a dielectric film coated around the inductively coupled coil Prepared,
The first electrode is an orifice electrode having a plurality of openings;
Wherein the presence of the dielectric film, the self-bias voltage is generated between the first electrode and the inductively coupled coils, from the generated plasma in the plasma generating chamber portion, through said first electrode particles A beam source characterized by extracting the beam. A beam processing apparatus for processing an object to be processed with a beam source, comprising: a beam source according to claim 1, and a stage for supporting an object to be processed so as to face the first electrode of the beam source A beam processing apparatus.

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