JP2004281231A - Beam source and beam treatment device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a beam source and a beam treatment device capable of uniformly irradiating various beams like positive ion, negative ion, neutral particles or the like in a large diameter on a treated object and realizing charge-free and damage-free properties. <P>SOLUTION: The device, provided with an antenna 2 generating plasma inside a plasma generating chamber, a first electrode 1 arranged inside the plasma generating chamber 4, and a potential difference generating means generating potential difference between the first electrode 1 and the antenna 2, draws out particle beams through the first electrode 1 from the plasma generated between the antenna 2 and the first electrode 1. <P>COPYRIGHT: (C)2005,JPO&NCIPI

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]
TECHNICAL FIELD 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 the like, and in particular, various beams such as high-directivity and high-density positive ions, negative ions, and neutral particles from high-density plasma. To a beam source and a beam processing apparatus for generating a beam.
[0002]
[Prior art]
In recent years, in the field of information storage media such as semiconductor integrated circuits and hard disks, or in the field of micro machines and the like, processing patterns have been significantly miniaturized. In the processing in such a field, an energy beam such as an ion beam having a high straightness (high directivity) and a relatively large diameter and a high density is irradiated to form a film or etch an object to be processed. Technology is attracting attention.
[0003]
As a beam source of such an energy beam, those generating various beams such as positive ions, negative ions, and neutral particles are known. By irradiating various beams such as positive ions, negative ions, and neutral particles from a beam source to an arbitrary portion of an object to be processed, local film formation and etching of the object to be processed, surface modification, Bonding, bonding, and the like can be performed.
[0004]
Devices for generating various beams such as positive ions, negative ions, and neutral particles, that is, a beam source and a beam processing device using the beam source are described in, for example, Patent Document 1, Patent Document 2, Patent Document 3, It is disclosed in Patent Literature 4, Patent Literature 5, Patent Literature 6, and the like.
[0005]
FIG. 11 shows an example of the basic configuration of the device disclosed in these documents. In this apparatus, an inductive coupling type coil 20 is arranged on the outer periphery of a beam generation chamber 40, and a first electrode 10 made of a conductor such as graphite is arranged at a lower end of the beam generation chamber 40. Above one electrode 10, a second electrode 50 also made of a conductor is arranged. A high-frequency current is caused to flow in the coil 20 to generate an induced magnetic field, and a time change of the magnetic field induces an electric field, and the electric field accelerates electrons 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.
You can do it.
[0006]
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, as a plasma generation source or a plasma processing apparatus using plasma. , Etc. are disclosed. Further, another device for generating a neutral particle beam is disclosed in US Pat.
[0007]
[Patent Document 1]
JP-A-2002-289399
[Patent Document 2]
JP-A-2002-289581
[Patent Document 3]
JP-A-2002-289582
[Patent Document 4]
JP-A-2002-289583
[Patent Document 5]
JP-A-2002-289584
[Patent Document 6]
JP-A-2002-289585
[Patent Document 7]
JP-A-10-125497
[Patent Document 8]
Japanese Patent No. 3114873
[Patent Document 9]
JP-T-2001-511945
[Patent Document 10]
JP 2001-507081 A
[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. 331838
[Patent Document 16]
US Pat. No. 6,331,701
[0008]
[Problems to be solved by the invention]
For mass production and cost reduction of semiconductor integrated circuits, etc., it is necessary to increase the diameter of the semiconductor integrated circuit manufacturing equipment. However, the diameter of the conventional beam source is increased, and positive ions, negative ions, neutral particles, etc. There are the following problems when trying to generate the various types of beams.
[0009]
First, in order to obtain a uniform beam with a large area, it is desirable that the density of the plasma as the element of the beam is 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, etc., an inductive coupling type coil is arranged 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 non-uniform in the radial direction, as in the case of a dense surrounding and a sparse center. When the diameter is as small as about 100 mm, sufficient energy is supplied from the coil also to the center 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 will not be supplied from the coil to the center of the beam generation chamber, and the plasma density will become non-uniform in the radial direction, and a uniform beam will be extracted. 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 large-diameter, uniform plasma, an inductively-coupled coil is required as disclosed in Patent Document 7, Patent Document 8, Patent Document 9, Patent Document 10, Patent Document 11, Patent Document 12, and the like. It is known to adopt a configuration of disposing the object to be treated.
[0011]
In these apparatuses, unless an appropriate neutralizing means is provided, charged particles such as positive ions and negative ions are irradiated to the object. In a beam source that irradiates an object with charged particles such as positive ions and negative ions, electric charge is accumulated in the object, so that an insulator cannot be processed (charge-up phenomenon). In addition, since the ion beam diverges due to the space charge effect, it is difficult to perform fine processing.
To prevent this, it has been considered to neutralize the charge by injecting electrons into the ion beam. However, in this method, although the overall charge can be balanced, the charge is locally unbalanced, and it is also difficult to perform fine processing.
[0012]
Further, in the case where ions are extracted from the plasma source and irradiated on the object to be processed, irradiation of the object with radiation such as ultraviolet rays generated from the plasma adversely affects the object. It is necessary to shield radiation such as ultraviolet rays emitted from the light source.
[0013]
In order to avoid the above problem, a large-diameter beam source capable of arbitrarily and uniformly generating 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 to face a workpiece in order to obtain a uniform plasma, and has an appropriate neutralizing means. Patent Document 16 discloses an apparatus having a configuration for blocking emitted radiation. As shown in FIG. 12, the neutral beam generator includes an RF inductor 93 connected to an RF power supply 91 via an impedance matching device 92, an RF window 94 disposed adjacent to the RF inductor 93, and an RF It comprises an RF acceleration means 97 connected to the acceleration circuit 96 and opposed to the RF inductor, and a sub-Debye neutralization grid 112 arranged opposite to the RF acceleration means 97 and set to the ground potential. By supplying RF power by the RF inductor 93, plasmas 95 and 99 are generated. Positive ions are accelerated from the plasma 99 toward the sub-Debye neutralization grid 112 due to a potential difference generated between the RF acceleration means 97 and the sub-Debye neutralization grid 112. A grid hole 117 is opened in the sub-Debye neutralization grid 112 so that accelerated positive ions are neutralized when passing through the grid hole 117.
[0014]
However, in order to emit a collimated beam with high neutralization efficiency, a grid hole of the sub-Debye neutralization grid 112 is formed by a sheath 111 formed between the plasma 99 and the sub-Debye neutralization grid 112. It is necessary that the diameter be smaller than the thickness and the aspect ratio be as high as about 10, which increases the manufacturing cost and limits the materials that can be manufactured. Therefore, aluminum is used in the beam generating apparatus, but aluminum is not suitable for a beam source having a large diameter of about 10 inches because of large thermal deformation (column 4, lines 45 to 48). Therefore, it is difficult to obtain a large-diameter, uniform beam using the technique disclosed in Patent Document 16.
[0015]
The present invention has been made in view of such problems of the related art, and a beam capable of uniformly irradiating an object to be treated with various beams such as positive ions, negative ions, and neutral particles with a large diameter. It is an object of the present invention to provide a source and a beam processing apparatus for processing an object to be processed using these beam sources. In particular, a damage-free beam source that does not cause a charge-up phenomenon (charge-free) and that can shield radiation light from plasma, and processes an object using these beam sources. It is an object to provide a beam processing device.
[0016]
[Means for Solving the Problems]
In order to solve such problems in the related art, one embodiment of the present invention provides an antenna that generates plasma in a plasma generation chamber, a first electrode disposed in the plasma generation chamber, and a first electrode. A potential difference generating means for generating a potential difference between the antenna and the antenna, wherein a particle beam is extracted from the plasma generated between the antenna and the first electrode via the first electrode. Beam source.
With such a configuration, the antenna also functions as one of the pair of electrodes necessary for extracting the particle beam, and it is not necessary to consider the interaction between the electrodes and the antenna (mutual interference). Therefore, since the antenna can be arranged at an arbitrary position so that the plasma density becomes uniform, various beams such as positive ions, negative ions, and neutral particles can be uniformly generated with a large diameter.
[0017]
In this case, it is preferable that the potential difference generating means for generating a potential difference between the first electrode and the antenna is a voltage applying means for alternately applying a high-frequency voltage and a DC voltage to the antenna. By applying a DC voltage, ions in the plasma can be accelerated toward the first electrode. In particular, when negative ions are accelerated, negative ions can be generated efficiently and continuously.
[0018]
Further, a potential difference generating means for generating a potential difference between the first electrode and the antenna is voltage applying means for alternately applying a high frequency voltage and a low frequency voltage to the antenna, and a dielectric material is provided adjacent to the antenna. Is preferably interposed. Accordingly, a self-bias voltage can be generated due to the presence of the dielectric adjacent to the antenna, and ions can be extracted from the plasma.
[0019]
Another embodiment of the present invention is a beam source, wherein the first electrode is a neutralizing means of the particle beam. With such a configuration, positive ions or negative ions are extracted from the plasma, neutralized, and a large-diameter uniform neutral beam with large kinetic energy and high linearity is obtained. It is possible to draw out.
[0020]
Further, another aspect of the present invention is a beam processing apparatus for processing an object to be processed using the beam source, comprising the beam source having the above-described configuration, and being processed so as to face the first electrode of the beam source. A stage for supporting a processing object is provided. By configuring a beam processing apparatus by selecting any one of the beam sources having the respective characteristics described above, a beam having a large kinetic energy and having a uniform diameter with a uniform diameter, such as neutral particles, can be obtained. It can be pulled out with high straightness. For this reason, the processing speed for the object to be processed is high, uniform processing can be performed on the entire surface of the object to be processed, and characteristics suitable for each use form of the beam processing apparatus can be exhibited. According to this apparatus, charge-free and damage-free processing can be performed.
[0021]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, a first embodiment of a beam source according to the present invention will be described with reference to FIGS. In the drawings, members or elements having the same operation or function are denoted by the same reference numerals, and redundant description will be omitted.
[0022]
As shown in FIG. 1, the beam source includes a cylindrical plasma generation chamber 4, a first electrode 1 disposed at a lower end of the plasma generation chamber 4, and a plasma generation chamber that generates plasma in the plasma generation chamber 4. 4 and an antenna 2 disposed in the antenna 4.
The wall surface 7 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 serves as a gas supply means together with a gas supply pipe (not shown) and a gas supply source (not shown). Make up. SF from this gas supply means ₆ , CHF ₃ , CF ₄ , Cl ₂ , Ar, O ₂ , N ₂ , C ₄ F ₈ Such a gas 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 a ground potential. This orifice electrode functions not only as a first electrode but also as a neutralizing means for particles constituting a beam. Here, this beam source is connected via a first electrode (orifice electrode) 1 to a vacuum chamber (not shown), and the vacuum chamber is depressurized by a vacuum pump connected thereto. The pressure in the plasma generation chamber 4 is mainly determined by the displacement of a vacuum pump connected to the vacuum chamber, the conductance of the orifice electrode, the type of gas supplied, and its flow rate.
[0024]
The antenna 2 is, for example, an inductively-coupled coil whose surface is arranged at the upper end inside the plasma generation chamber 4 so as to face the first electrode 1 and is a conductor. This antenna is connected to a high-frequency power supply 3 via a matching box (not shown), and for example, a high-frequency voltage of 13.56 MHz is applied to the antenna. These antennas, the matching box, and the high-frequency power supply 3 constitute a plasma generating unit. That is, a high-frequency current is caused to flow through the antenna to generate an induced magnetic field, and the time change of the magnetic field induces an electric field, and the electric field accelerates electrons to generate plasma. In this manner, the plasma can be uniformly generated in the plasma generation chamber by disposing the antenna for generating the plasma at an appropriate position in the plasma generation chamber.
[0025]
Here, the plasma formed when a 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, when a series of operations such as applying a high-frequency voltage supplied from the high-frequency power supply 3 to the antenna for 10 μs as shown in FIG. The plasma can be continuously generated, and a plasma in which positive ions and negative ions coexist can be generated. Here, while the negative ions are neutralized without being positively ionized during the application of the high-frequency voltage, the electrons heated during the application of the high-frequency voltage stop applying the high-frequency voltage. Produced by impact and predominantly causing dissociative adhesion.
[0026]
As described above, by the method of supplying the high-frequency voltage from the high-frequency power supply 3, it is possible to generate two types of plasma, a plasma mainly composed of positive ions and heated electrons, and a plasma in which positive ions and negative ions coexist. it can. Note that the form of this antenna may be a form of a water cooling pipe for cooling itself. Since the antenna 2 and the high-frequency power supply 3 are connected in series with a DC bias power supply 6 which is a potential difference generating means, the potential of the antenna 2 is higher than the potential of the first electrode 1 (ground potential). As shown in FIGS. 2C and 2D, a difference is caused by a potential given by the sum of the potential of the high-frequency power supply 3 and the potential of the bias power supply 6. 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 plasma mainly composed of positive ions and heated electrons and plasma in which positive ions and negative ions coexist (FIG. 2C )), 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 mainly neutralized by being given electrons near the solid surface on the peripheral wall of the orifice, or recombine with electrons emitted from the surface of the orifice electrode. Then, the neutralized particles are 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. 2D), the negative ions in the plasma cause the orifice due to this potential difference. It is accelerated toward the electrode and enters the orifice formed in the orifice electrode. Negative ions passing through the inside of the orifice of the orifice electrode are mainly neutralized by depriving electrons near the solid surface on the peripheral wall of the orifice, or are neutralized by charge exchange with gas remaining inside the orifice. And a neutral beam can be extracted.
[0029]
As shown in FIG. 3, the antenna 2 may be formed by coating the copper pipe 2a with another conductor 2b, for example, graphite. According to this, since the copper pipe 2a can be protected from plasma, it is possible to prevent copper particles from being mixed into the particle beam.
[0030]
Further, the shape of the antenna 2 may be, for example, a large-diameter helical coil having a size about the diameter of the plasma generation chamber, a substantially circular loop-shaped coil, or two or more loop-shaped coils. The shape may be connected in parallel. Since a large-diameter coil has a large impedance, a plurality of small antennas may be installed. As described above, the antenna may be of any structure and form as long as it can generate uniform plasma in the plasma generation chamber by proper arrangement.
[0031]
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 emitted from plasma can be emitted from the first electrode (orifice electrode). Can realize a beam source that can be shielded. That is, a damage-free beam source free of damage due to the charge-up phenomenon and damage due to radiation light can be realized. In addition, the antenna also serves as one of the pair of electrodes required to extract the beam, so that it is not necessary to consider the interaction between the electrodes and the antenna (mutual interference). Therefore, the antenna 2 can be arranged at an arbitrary position in the plasma generation chamber so that the plasma density becomes uniform. Therefore, both generation of a large-diameter and uniform plasma 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. Members or elements having the same functions or functions as those of the first embodiment described above are denoted by the same reference numerals, and parts that are not particularly described are the same as those of the first embodiment.
[0033]
As shown in FIG. 4, the beam source includes a cylindrical plasma generation chamber 4, a first electrode 1 disposed at a lower end of the plasma generation chamber 4, and a plasma generation chamber that generates plasma in the plasma generation chamber 4. 4 includes an antenna 2 disposed therein.
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 serves as a gas supply means together with a gas supply pipe (not shown) and a gas supply source (not shown). Make up. SF from this gas supply means ₆ , CHF ₃ , CF ₄ , Cl ₂ , Ar, O ₂ , N ₂ , C ₄ F ₈ Such a gas 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 a ground potential. This orifice electrode functions not only as a first electrode but also as a neutralizing means for particles constituting a beam.
[0034]
Here, this beam source is connected via a first electrode (orifice electrode) 1 to a vacuum chamber (not shown), and the vacuum chamber is depressurized by a vacuum pump connected thereto. The pressure in the plasma generation chamber 4 is mainly determined by the displacement of a vacuum pump connected to the vacuum chamber, the conductance of the orifice electrode, the type of gas supplied, and its flow rate.
[0035]
The antenna 2 is, for example, an inductively-coupled coil whose surface is arranged at the upper end inside the plasma generation chamber 4 so as to face the first electrode 1 and is a conductor. The antenna 2 is connected to a high-frequency power supply 3 via a matching box (not shown), and a high-frequency voltage of, for example, 13.56 MHz is applied to the antenna. The antenna 2, the matching box, and the high-frequency power supply 3 constitute a plasma generating unit. That is, a high-frequency current is caused to flow through the antenna to generate an induced magnetic field, and the time change of the magnetic field induces an electric field, and the electric field accelerates electrons to generate plasma. In this manner, the plasma can be uniformly generated in the plasma generation chamber by disposing 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 the high-frequency voltage from the high-frequency power supply 3, the plasma mainly composed of the positive ions and the heated electrons and the plasma in which the positive ions and the negative ions coexist are formed. , Two types of plasma can be generated. Note that the form of this antenna may be a form of a water cooling pipe for cooling itself.
[0037]
The antenna 2 is also connected to a DC bias power supply 6. The bias power supply 6 constitutes a voltage applying unit together with the high-frequency power supply 3, and as shown in FIG. 5, can apply a high-frequency voltage from the high-frequency power supply 3 and a DC voltage from the bias power supply 6 to the antenna alternately. . Here, the time during which the DC voltage is applied is sufficiently shorter than the time when the plasma disappears. Then, since the surface of the antenna is a conductor, a series of operations of generating a plasma by applying a high-frequency voltage and then extracting a beam by applying a DC voltage can be repeated.
[0038]
For example, in a plasma mainly composed of positive ions and heated electrons, and a plasma in which positive ions and negative ions coexist, the DC voltage applied to the antenna by the bias power supply 6 is changed to a positive bias voltage as shown by a solid line in FIG. 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. Positive ions passing through the inside of the orifice of the orifice electrode 1 are mainly neutralized by being given electrons near the solid surface on the peripheral wall of the orifice, or collide with electrons emitted from the surface of the orifice electrode to be regenerated. Neutralized by the 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 supply 6 as shown by the broken line in FIG. 5, the potential of the first electrode (orifice electrode) 1 becomes Since the potential is higher than the potential, the 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 passing through the inside of the orifice of the orifice electrode are mainly neutralized by depriving electrons near the solid surface on the peripheral wall of the orifice, or are neutralized by charge exchange with gas remaining inside the orifice. And a neutral beam can be extracted. Here, as shown by a two-dot chain line in FIG. 5, between the application of the high-frequency voltage and the application of the DC voltage, for example, a negative ion generation time in which no voltage is applied for about 50 μsec may be provided. With this configuration, when a DC 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]
Note that, similarly to the first embodiment, the antenna 2 may be formed by coating a copper pipe with another conductor, for example, 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 about the diameter of the plasma generation chamber, a substantially circular loop-shaped coil, or two or more loop-shaped coils arranged in parallel. May be connected. Since a large-diameter coil has a large impedance, a plurality of small antennas may be installed. As described above, the antenna may be of any structure and form as long as it can generate uniform plasma in the plasma generation chamber by proper arrangement.
[0041]
As described above, 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 light emitted from the plasma is emitted from the first electrode (orifice electrode) 1. A beam source that can be shielded can be realized. That is, a damage-free beam source free of damage due to the charge-up phenomenon and damage due to radiation light can be realized. In addition, the antenna also serves as one of the pair of electrodes required to extract the beam, so that it is not necessary to consider the interaction between the electrodes and the antenna (mutual interference). Therefore, the antenna can be arranged at an arbitrary position in the plasma generation chamber so that the plasma density becomes uniform. Therefore, both the generation of a large-diameter and uniform plasma and the extraction of a 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. Members or elements having the same functions or functions as those of the first embodiment described above are denoted by the same reference numerals, and parts that are not particularly described are the same as those of the first embodiment.
As shown in FIG. 6, the beam source includes a cylindrical plasma generation chamber 4, a first electrode 1 disposed at a lower end of the plasma generation chamber 4, and an antenna 2 for generating 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 serves as a gas supply means together with a gas supply pipe (not shown) and a gas supply source (not shown). Make up. SF from this gas supply means ₆ , CHF ₃ , CF ₄ , Cl ₂ , Ar, O ₂ , N ₂ , C ₄ F ₈ Such a gas 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 a ground potential. This orifice electrode functions not only as a first electrode but also as a neutralizing means for particles constituting a beam.
[0044]
Here, this beam source is connected via a first electrode (orifice electrode) 1 to a vacuum chamber (not shown), and the vacuum chamber is depressurized by a vacuum pump connected thereto. The pressure in the plasma generation chamber 4 is mainly determined by the displacement of a vacuum pump connected to the vacuum chamber, the conductance of the orifice electrode, the type of gas supplied, and its flow rate.
[0045]
The antenna 2 is, for example, an inductively-coupled coil disposed at an upper end inside the plasma generation chamber 4 so as to face the first electrode 1. This antenna is connected to a high-frequency power supply 3 via a matching box (not shown), and for example, a high-frequency voltage of 13.56 MHz is applied to the antenna. These antennas, the matching box, and the high-frequency power supply 3 constitute a plasma generating unit. That is, a high-frequency current is caused to flow through the antenna 2 to generate an induced magnetic field, and a time change of the magnetic field induces an electric field, and the electric field accelerates electrons to generate plasma. In this manner, the plasma can be uniformly generated in the plasma generation chamber by disposing 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 the high-frequency voltage from the high-frequency power supply 3, the plasma mainly composed of the positive ions and the heated electrons and the plasma in which the positive ions and the negative ions coexist are obtained. , Two types of plasma can be generated. Note that the form of this antenna may be 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, for example, 600 kHz. The bias power supply 6 constitutes a voltage applying means together with the high-frequency power supply 3 and, as shown in FIG. 7A, alternately applies a high-frequency voltage from the high-frequency power supply 3 and a low-frequency voltage from the bias power supply 6 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 disappears. 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, a series of operations of generating a plasma by applying a high-frequency voltage and then extracting a beam by applying a low-frequency voltage can be repeated.
[0048]
Here, the DC component V of the self-bias voltage _DC It can be considered that Equation (1) is simply expressed by 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 supply 6.
(Equation 1)

Here, α is a coefficient.
[0049]
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 <αSk, V _DC Becomes positive and the potential of the first electrode (orifice electrode) 1 becomes lower than the potential of the antenna, so that 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 mainly neutralized by being given electrons near the solid surface on the peripheral wall of the orifice, or recombine with electrons emitted from the surface of the orifice electrode. Then, the neutralized particles are 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, so that the 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 passing through the inside of the orifice of the orifice electrode are mainly neutralized by depriving electrons near the solid surface on the peripheral wall of the orifice, or are neutralized by charge exchange with gas remaining inside the orifice. And a neutral beam can be extracted. Here, as shown in FIG. 7B, a negative ion generation time T in which no voltage of, for example, about 50 μs is applied may be provided between the application of the high-frequency voltage and the application of the DC voltage. With this configuration, when a DC 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 about the diameter of the plasma generation chamber, a substantially circular loop-shaped coil, or two or more loop-shaped coils arranged in parallel. May be connected. Since a large-diameter coil has a large impedance, a plurality of small antennas may be installed. As described above, the antenna may be of any structure and form as long as it can generate uniform plasma in the plasma generation chamber by proper arrangement.
[0052]
As described above, a neutral particle beam can be extracted, so that a charge-free beam source that does not cause a charge-up phenomenon to be processed can be realized, and radiation emitted from plasma is shielded by the first electrode (orifice electrode). Beam source that can be used. That is, it is possible to realize a damage-free beam source free from damage due to the charge-up phenomenon and damage due to radiation light. In addition, since the antenna also serves as one of the pair of electrodes required to extract the beam, it is not necessary to consider the interaction between the electrodes and the antenna (mutual interference). Therefore, the antenna can be arranged at an arbitrary position in the plasma generation chamber so that the plasma density becomes uniform. Therefore, both generation of a large-diameter and uniform plasma 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. Members or elements having the same functions or functions as those of the first embodiment described above are denoted by the same reference numerals, and parts that are not particularly described are the same as those of the first embodiment.
As shown in FIG. 8A, this beam source generates a plasma in the plasma generation chamber 4, a first electrode 1 disposed at a lower end of the plasma generation chamber 4, and a cylindrical plasma generation chamber 4. And an antenna 2 disposed in the plasma generation chamber 4.
[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 serves as a gas supply means together with a gas supply pipe (not shown) and a gas supply source (not shown). Make up. SF from this gas supply means ₆ , CHF ₃ , CF ₄ , Cl ₂ , Ar, O ₂ , N ₂ , C ₄ F ₈ Such a gas 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 a ground potential. This orifice electrode functions not only as a first electrode but also as a neutralizing means for particles constituting a beam.
[0055]
Here, this beam source is connected via a first electrode (orifice electrode) 1 to a vacuum chamber (not shown), and the vacuum chamber is depressurized by a vacuum pump connected thereto. The pressure in the plasma generation chamber 4 is mainly determined by the displacement of a vacuum pump connected to the vacuum chamber, the conductance of the orifice electrode, the type of gas supplied, and its flow rate.
[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 has a surface covered with a dielectric 9. The form of the antenna 2 may be in the form of a water cooling pipe for cooling itself. The antenna 2 may have a form in which a copper pipe 2a is covered with one or more dielectric films 2c such as quartz as shown in FIG. 8B, for example, or as shown in FIG. 8C. The copper pipe 2a may be covered with a dielectric tube 2e via a hollow portion 2d of gas or vacuum.
[0057]
This antenna is connected to a high-frequency power supply 3 via a matching box (not shown), and for example, a high-frequency voltage of 13.56 MHz is applied to the antenna. These antennas, the matching box, and the high-frequency power supply 3 constitute a plasma generating unit. That is, a high-frequency current is caused to flow through the antenna to generate an induced magnetic field, and the time change of the magnetic field induces an electric field, and the electric field accelerates electrons to generate plasma. In this manner, the plasma can be uniformly generated in the plasma generation chamber by disposing 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 the high-frequency voltage from the high-frequency power supply 3, the plasma mainly composed of the positive ions and the heated electrons and the plasma in which the positive ions and the negative ions coexist are formed. , 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, for example, 600 kHz. The bias power supply 6 constitutes a voltage applying means together with the high-frequency power supply 3 and, as shown in FIG. 7A, alternately applies a high-frequency voltage from the high-frequency power supply 3 and a low-frequency voltage from the bias power supply 6 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 disappears. Then, since the surface of the antenna is covered with the dielectric, a self-bias voltage is generated between the antenna 2 and the first electrode 1 when a low frequency voltage is applied, so that the beam can be extracted. Therefore, a series of operations of generating a plasma by applying a high-frequency voltage and then extracting a beam by applying a low-frequency voltage can be repeated.
[0059]
Here, the DC component V of the self-bias voltage _DC Equation (2) is considered to be simply expressed by the area Sa of the first electrode 1, the surface area Sl of the dielectric covering the antenna, and the amplitude V of the voltage of the bias power supply 6.
(Equation 2)

[0060]
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 <Sl, V _DC Becomes positive and the potential of the first electrode (orifice electrode) 1 becomes lower than the potential of the antenna, so that 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 mainly neutralized by being given electrons near the solid surface on the peripheral wall of the orifice, or recombine with electrons emitted from the surface of the orifice electrode. Then, the neutralized particles are 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, in a plasma in which positive ions and negative ions coexist, if Sa> Sl, V _DC Becomes negative and the potential of the first electrode (orifice electrode) 1 becomes higher than the potential of the antenna, so that the 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 passing through the inside of the orifice of the orifice electrode are mainly neutralized by depriving electrons near the solid surface on the peripheral wall of the orifice, or are neutralized by charge exchange with gas remaining inside the orifice. And a neutral beam can be extracted. Here, as shown in FIG. 7B, a negative ion generation time T in which no voltage of, for example, about 50 μs is applied may be provided between the application of the high-frequency voltage and the application of the DC voltage. With this configuration, when a DC 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]
The shape of the antenna may be, for example, a large-diameter helical coil having a size about the diameter of the plasma generation chamber, a substantially circular loop-shaped coil, or two or more loop-shaped coils arranged in parallel. May be connected. Since a large-diameter coil has a large impedance, a plurality of small antennas may be installed. As described above, the antenna may be of any structure and form as long as it can generate uniform plasma in the plasma generation chamber by proper arrangement.
[0063]
As described above, a neutral particle beam can be extracted, so that a charge-free beam source that does not cause a charge-up phenomenon to be processed can be realized, and radiation emitted from plasma is shielded by the first electrode (orifice electrode). A beam source that can be used is realized. That is, it is possible to realize a damage-free beam source free from damage due to the charge-up phenomenon and damage due to radiation light. In addition, since the antenna also serves as one of the pair of electrodes required for extracting a beam, it is not necessary to consider the electrode and the antenna. Therefore, since the antenna can be arranged at any place in the plasma generation chamber so that the plasma density becomes uniform, it is easy to generate both a large-diameter and uniform plasma and to extract the neutral beam from the plasma. 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. Members or elements having the same functions or functions as those of the first embodiment described above are denoted by the same reference numerals, and parts that are not particularly described are the same as those of the first 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 generating a 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 serves as a gas supply means together with a gas supply pipe (not shown) and a gas supply source (not shown). Make up. SF from this gas supply means ₆ , CHF ₃ , CF ₄ , Cl ₂ , Ar, O ₂ , N ₂ , C ₄ F ₈ Such a gas 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 a ground potential. This orifice electrode functions not only as a first electrode but also as a neutralizing means for particles constituting a beam.
Here, this beam source is connected via a first electrode (orifice electrode) 1 to a vacuum chamber (not shown), and the vacuum chamber is depressurized by a vacuum pump connected thereto. The pressure in the plasma generation chamber 4 is mainly determined by the displacement of a vacuum pump connected to the vacuum chamber, the conductance of the orifice electrode, the type of gas supplied, and its flow rate. The antenna 2 is, for example, an inductively-coupled coil disposed at an upper end inside the plasma generation chamber 4 so as to face the first electrode 1. The form of the antenna 2 may be in the form of a water cooling pipe for cooling itself.
[0066]
The antenna 2 is connected to a high-frequency power supply 3 via a matching box (not shown), and a high-frequency voltage of, for example, 13.56 MHz is applied to the antenna. The antenna 2, the matching box, and the high-frequency power supply 3 constitute a plasma generating unit. That is, a high-frequency current is caused to flow through the antenna to generate an induced magnetic field, and the time change of the magnetic field induces an electric field, and the electric field accelerates electrons to generate plasma. In this manner, the plasma can be uniformly generated in the plasma generation chamber by disposing 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 the high-frequency voltage from the high-frequency power supply 3, the plasma mainly composed of the positive ions and the heated electrons and the plasma in which the positive ions and the negative ions coexist are obtained. , 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, for example, 600 kHz via a dielectric 6c such as a capacitor. The bias power supply 6 constitutes a voltage applying means together with the high-frequency power supply 3, and as shown in FIG. 7A, a high-frequency voltage from the high-frequency power supply 3 and a low-frequency voltage from the bias power supply 6 are alternately applied 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 disappears. Then, since the antenna is connected to the bias power supply 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, so that the beam can be extracted. it can. Therefore, a series of operations of generating a plasma by applying a high-frequency voltage and then extracting a beam by applying a low-frequency voltage can be repeated.
Here, the DC component V of the self-bias voltage _DC Equation (3) is considered to be simply expressed by 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 supply 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 Becomes positive and the potential of the first electrode (orifice electrode) 1 becomes lower than the potential of the antenna, so that 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 mainly neutralized by being given electrons near the solid surface on the peripheral wall of the orifice, or recombine with electrons emitted from the surface of the orifice electrode. Then, the neutralized particles are 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, in a plasma in which positive ions and negative ions coexist, if Sa> Sm, V _DC Becomes negative and the potential of the first electrode (orifice electrode) 1 becomes higher than the potential of the antenna, so that the 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 passing through the inside of the orifice of the orifice electrode are mainly neutralized by depriving electrons near the solid surface on the peripheral wall of the orifice, or are neutralized by charge exchange with gas remaining inside the orifice. And a neutral beam can be extracted. Here, as shown in FIG. 7B, a negative ion generation time T in which no voltage of, for example, about 50 μs is applied may be provided between the application of the high-frequency voltage and the application of the DC voltage. With this configuration, when a DC 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 about the diameter of the plasma generation chamber, a substantially circular loop-shaped coil, or two or more loop-shaped coils arranged in parallel. May be connected. Since a large-diameter coil has a large impedance, a plurality of small antennas may be installed. As described above, the antenna may be of any structure and form as long as it can generate uniform plasma in the plasma generation chamber by proper arrangement.
[0071]
As described above, a neutral particle beam can be extracted, so that a charge-free beam source that does not cause a charge-up phenomenon to be processed can be realized, and radiation emitted from plasma is shielded by the first electrode (orifice electrode). A beam source that can be used is realized. That is, it is possible to realize a damage-free beam source free from damage due to the charge-up phenomenon and damage due to radiation light. In addition, since the antenna also serves as one of the pair of electrodes required to extract a beam, there is no need to consider the interaction between the electrodes and the antenna (mutual interference). Therefore, the antenna can be arranged at an arbitrary position in the plasma generation chamber so that the plasma density becomes uniform. Therefore, both generation of a large-diameter and uniform plasma and extraction of a neutral particle beam from the plasma can be realized with a simple configuration.
[0072]
Further, in the embodiments described so far, an example was described in which positive ions or negative ions were extracted and neutralized to form a neutral particle beam. However, instead of the orifice electrode, the first electrode 1 was replaced with, for example, graphite. By using a grid electrode in the form of a thin grid formed of a conductor such as a conductor, positive ions or negative ions can be extracted and extracted as a positive ion beam or a negative ion beam without being neutralized. .
[0073]
Next, an embodiment of a beam processing apparatus according to the present invention will be described with reference to FIG. This figure shows a case where 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 a first electrode 1, a plasma generation chamber 4, an antenna 2, a high frequency power supply 3, and a bias power supply 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.
[0075]
Further, a vacuum chamber 30 is disposed below and adjacent to the first electrode 1, and the pressure in the vacuum chamber is reduced by a vacuum pump 31 connected thereto. The pressure in the plasma generation chamber 4 is mainly determined by the displacement 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. Thus, a beam processing apparatus capable of irradiating an object to be processed with a large-diameter uniform beam from a beam source can be realized.
[0076]
In addition, since the beam to be processed is a neutral particle beam, the workpiece 33 can be processed in a charge-free manner. For example, generation of defects due to a charge-up phenomenon such as dielectric breakdown caused by static electricity generated in fine wiring. Can be minimized, and the yield of the object to be processed can be significantly improved. Further, since the light emitted from the plasma with respect to the object 33 can be shielded by the first electrode 1, the generation of defects due to the emitted light can be minimized, and the yield of the object can be significantly improved. Can be improved.
[0077]
Here, the stage 32 may be configured such that the relative movement with respect to the first electrode 1 can be, for example, a rotational movement or a linear movement. By appropriately moving the stage 32 relative to the first electrode 1 while irradiating a large-diameter uniform beam from the beam source, the object 33 can be uniformly and rapidly processed over the entire surface to be processed. .
As described above, according to the beam processing apparatus of the present invention, an object to be processed can be uniformly irradiated with various beams such as positive ions, negative ions, and neutral particles with a large diameter. In addition, a damage-free beam processing apparatus that does not cause a charge-up phenomenon (charge-free) and that can shield emitted light from plasma can be realized.
[0078]
Although the embodiments relating to the beam source and the beam processing device of the present invention have been described above, the beam source and the beam processing device of the present invention are not limited to the above-described embodiments, but may be variously modified within the scope of the technical idea. Needless to say, this may be implemented.
[0079]
【The invention's effect】
As described above, according to the present invention, it is possible to uniformly irradiate an object to be processed with a large diameter and various beams such as positive ions, negative ions, and neutral particles, and to realize charge-free and damage-free. The beam source can be provided with a compact structure. Further, by the beam processing apparatus equipped with the beam source of the present invention, the processing of the processing object can be performed uniformly and quickly, and the processing of the processing object with a high yield can be performed.
[Brief description of the drawings]
FIG. 1 is a diagram illustrating an overall configuration of a beam source according to a first embodiment of the present invention.
FIG. 2 is a waveform diagram showing application of a voltage.
FIG. 3 is a cross-sectional view of an antenna having a conductor on its surface.
FIG. 4 is a diagram illustrating an overall configuration of a beam source according to a second embodiment of the present invention.
FIG. 5 is a waveform chart showing application of a voltage.
FIG. 6 is a diagram illustrating an overall configuration of a beam source according to a third embodiment of the present invention.
FIG. 7 is a waveform chart showing application of a voltage.
FIG. 8A is a diagram 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 illustrating an overall configuration of a beam source according to a fifth embodiment of the present invention.
FIG. 10 is a diagram schematically illustrating an entire beam processing apparatus according to 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 the 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 (8)

An antenna for generating plasma in a plasma generation chamber; a first electrode disposed in the plasma generation chamber; and a potential difference generating unit configured to generate a potential difference between the first electrode and the antenna. A beam source for extracting a particle beam from the plasma generated between the first electrode and the plasma through the first electrode. 2. The beam according to claim 1, wherein the potential difference generating means for generating a potential difference between the first electrode and the antenna is voltage applying means for alternately applying a high frequency voltage and a DC voltage to the antenna. source. Potential difference generating means for generating a potential difference between the first electrode and the antenna is voltage applying means for alternately applying a high-frequency voltage and a low-frequency voltage to the antenna, and a dielectric is provided adjacent to the antenna. The beam source according to claim 1, wherein Potential difference generating means for generating a potential difference between the first electrode and the antenna is voltage applying means for alternately applying a high-frequency voltage and a low-frequency voltage to the antenna, and between the antenna and the first electrode. The beam source according to claim 1, wherein a dielectric is interposed. The beam source according to claim 3, wherein a surface of the antenna is covered with a dielectric. 2. The beam source according to claim 1, wherein the first electrode is an orifice electrode having a large number of openings, and neutralizes particles extracted from the plasma at the openings. The beam source according to claim 1, wherein the antenna has a graphite coating on a surface thereof. 8. A beam processing apparatus for processing an object using a beam source, the stage supporting the object to be processed so as to face the beam source according to claim 1 and a first electrode of the beam source. A beam processing device comprising:

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