JP4131793B2

JP4131793B2 - High frequency power supply and control method thereof, and plasma processing apparatus

Info

Publication number: JP4131793B2
Application number: JP2001375961A
Authority: JP
Inventors: 利泰速水; 剛大瀬; 淳一高平; 淳一島田
Original assignee: Tokyo Electron Ltd
Current assignee: Tokyo Electron Ltd
Priority date: 2001-12-10
Filing date: 2001-12-10
Publication date: 2008-08-13
Anticipated expiration: 2021-12-10
Also published as: JP2003179030A

Description

【０００１】
【発明の属する技術分野】
本発明は、高周波電源及びその制御方法、並びにプラズマ処理装置に関し、特に、半導体ウエハに対してプラズマ処理を行うプラズマ処理装置の高周波電源及びその制御方法に関する。
【０００２】
【従来の技術】
従来、半導体デバイスの製造プロセスでは、比較的低圧の雰囲気内で高密度のプラズマを生成して半導体ウエハ（以下、単に「ウエハ」という。）にエッチングを行うプラズマ処理装置が用いられている。例えば、平行平板プラズマ処理装置は、プラズマチャンバ内に一対の平行平板電極（上部及び下部電極）を配置し、処理ガスを該チャンバ内に導入すると共に、電極の一方に高周波を印加して電極間に高周波電界を生成し、この高周波電界により処理ガスのプラズマを生成してウエハにエッチングを行っている。
【０００３】
このようなプラズマ処理装置は、エッチングを効率よく行うため下部電極にプラズマ生成用の高周波とプラズマ中のイオンを引き込むためのバイアス用の高周波とを重畳して同時に印加する。具体的には、プラズマ生成用の高周波電源を整合回路（以下「マッチングボックス」という。）を介して下部電極に接続すると共に、バイアス用の高周波電源をマッチングボックスを介して下部電極に接続して２つの高周波を重畳させる。プラズマ生成用高周波は、プラズマの生成効率を考慮して１００ＭＨｚの周波数に設定されている一方、バイアス用高周波は、３．２ＭＨｚの周波数に設定されている。
【０００４】
上記プラズマ処理装置では、プラズマ処理の際に、主周波数である１００ＭＨｚ，３．２ＭＨｚそれぞれに対応する高調波や変調波が発生し、これら高調波や変調波が入射波（Ｐｆ）の主周波数近傍に現れると共に（図４（ａ））、反射波（Ｐｒ）の主周波数近傍にも現れて（図４（ｂ））、マッチングボックスや高周波電源に誤動作等を引き起こしている。そのため、高周波電源は、入射波及び反射波を検出して高周波出力を制御するパワーモニタを備えており、該パワーモニタがＬＣ回路から成るバンドパスフィルタ等を含む検波回路（図５）により高調波や変調波を除去している。
【０００５】
【発明が解決しようとしている課題】
しかしながら、上記従来のバンドパスフィルタを備える高周波電源では、入射波であるプラズマ生成用高周波とバイアス用高周波との周波数の差が大きくなると、反射波に含まれる主周波数と変調波等の周波数との差が小さくなり、ＬＣ回路で構成されたバンドパスフィルタにより変調波等の減衰を十分に行えず、その結果、変調波等を反射波と見なしてしまい、高周波電源が誤動作を起こすおそれがあった。
【０００６】
また、変調波等の減衰が十分に行えないと、プラズマ処理時に適正な高周波を印加することが困難であった。
【０００７】
本発明は、上記問題に鑑みて成されたものであり、プラズマ生成時に発生する高調波や変調波を精度よく除去して誤動作を防止すると共に、適正な高周波を印加することができる高周波電源及びその制御方法、並びにプラズマ処理装置を提供することを目的とする。
【０００８】
【課題を解決するための手段】
上記目的を達成するために、請求項１記載の高周波電源は、プラズマ処理容器内に下部電極が配置されたプラズマ処理装置の高周波電源であって、前記下部電極に接続された第１の高周波電源及び第２の高周波電源を備え、前記第１の高周波電源は、前記プラズマ処理容器内にプラズマを生成するための第１の高周波を発生する高周波発生源と、前記第１の高周波を取り出す高周波取り出し手段と、前記第１の高周波と異なる周波数の第２の高周波を発振する発振手段と、前記高周波取り出し手段により取り出された第１の高周波及び前記発振手段により発振された第２の高周波を乗算する乗算手段と、前記乗算手段により乗算された結果から高調波及び変調波の成分を含む高周波分を減衰・除去する高周波減衰手段と、前記高周波減衰手段から出力される１０Ｈｚ〜５００ｋＨｚの範囲の周波数を検波する検波手段と、前記検波手段からの検波出力と、前記高周波発生源の出力を設定するための基準電圧とを比較し、当該比較結果に基づいて前記高周波発生源の出力を制御する制御手段とを備えることを特徴とする。
請求項２記載の高周波電源は、請求項１記載の高周波電源において、前記高周波発生源が発生する第１の高周波の周波数は、前記第２の高周波電源からの出力の周波数より高い周波数であることを特徴とする。
請求項３記載の高周波電源は、請求項１又は２記載の高周波電源において、前記高周波減衰手段からの出力の周波数は、前記第２の高周波電源からの出力の周波数より低い周波数であることを特徴とする。
請求項４記載の高周波電源は、請求項１乃至３のいずれか１項に記載の高周波電源において、前記第２の高周波電源は第３の高周波を発生する他の高周波発生源を備え、前記下部電極及び前記他の高周波発生源の間に整合器が配置され、且つ前記下部電極及び前記整合器の間にローパスフィルタが配置されることを特徴とする。
上記目的を達成するために、請求項５記載の高周波電源は、プラズマ処理容器内に下部電極が配置されたプラズマ処理装置の高周波電源であって、前記下部電極に接続された第１の高周波電源と、前記下部電極に接続された、前記第１の高周波電源が出力する第１の高周波の周波数よりも低い周波数の高周波を出力する第２の高周波電源とを備え、前記第１の高周波電源は、前記プラズマ処理容器内にプラズマを生成するための第１の高周波を発生する高周波発生源と、前記第１の高周波を取り出す高周波取り出し手段と、前記第１の高周波と異なる周波数の第２の高周波を発振する発振手段と、前記高周波取り出し手段により取り出された第１の高周波及び前記発振手段により発振された第２の高周波を乗算する乗算手段と、前記乗算手段により乗算された結果から高調波及び変調波の成分を含む高周波分を減衰するローパスフィルタと、前記ローパスフィルタから出力される、前記第２の高周波電源からの出力の周波数よりも低い周波数の出力を検波する検波手段と、前記検波手段からの検波出力と、前記高周波発生源の出力を設定するための基準電圧とを比較し、当該比較結果に基づいて前記高周波発生源の出力を制御する制御手段とを備えることを特徴とする。
請求項６記載の高周波電源は、請求項５記載の高周波電源において、前記第２の高周波電源は第３の高周波を発生する他の高周波発生源を備え、前記下部電極及び前記他の高周波発生源の間に整合器が配置され、且つ前記下部電極及び前記整合器の間に他のローパスフィルタが配置されることを特徴とする。
請求項７記載の高周波電源は、請求項５又は６記載の高周波電源において、前記検波手段は前記ローパスフィルタから出力される１０Ｈｚ〜５００ｋＨｚの範囲の周波数を検波することを特徴とする。
請求項８記載の高周波電源は、請求項５乃至７のいずれか１項に記載の高周波電源において、前記検波手段は理想検波器を有しており、当該理想検波器により前記ローパスフィルタからの出力を直流にすることを特徴とする。
【００１２】
上記目的を達成するために、請求項９記載の高周波電源の制御方法は、プラズマ処理容器内に下部電極が配置されたプラズマ処理装置の高周波電源の制御方法であって、前記高周波電源は、前記下部電極に接続された第１の高周波電源及び第２の高周波電源を備え、前記第１の高周波電源は、前記プラズマ処理容器内にプラズマを生成するための第１の高周波を発生する高周波発生源を備え、前記第１の高周波を取り出す高周波取り出し工程と、前記第１の高周波と異なる周波数の第２の高周波を発振する発振工程と、前記高周波取り出し工程にて取り出された第１の高周波及び前記発振工程にて発振された第２の高周波を乗算する乗算工程と、前記乗算工程にて乗算された結果から高調波及び変調波の成分を含む高周波分を減衰・除去する高周波減衰工程と、前記高周波減衰工程後に出力される１０Ｈｚ〜５００ｋＨｚの範囲の周波数を検波する検波工程と、前記検波工程後の検波出力と、前記高周波発生源の出力を設定するための基準電圧とを比較し、当該比較結果に基づいて前記高周波発生源の出力を制御する制御工程とを有することを特徴とする。
上記目的を達成するために、請求項１０記載の高周波電源の制御方法は、プラズマ処理容器内に下部電極が配置されたプラズマ処理装置の高周波電源の制御方法であって、前記高周波電源は、前記下部電極に接続された第１の高周波電源と、前記下部電極に接続された、前記第１の高周波電源が出力する第１の高周波の周波数よりも低い周波数の高周波を出力する第２の高周波電源とを備え、前記第１の高周波電源は、前記プラズマ処理容器内にプラズマを生成するための第１の高周波を発生する高周波発生源を備え、前記第１の高周波を取り出す高周波取り出し工程と、前記第１の高周波と異なる周波数の第２の高周波を発振する発振工程と、前記高周波取り出し工程にて取り出された第１の高周波及び前記発振工程にて発振された第２の高周波を乗算する乗算工程と、前記乗算工程にて乗算された結果から高調波及び変調波の成分を含む高周波分をローパスフィルタにより減衰する高周波減衰工程と、前記高周波減衰工程にて出力される、前記第２の高周波電源からの出力の周波数よりも低い周波数の出力を検波する検波工程と、前記検波工程後の検波出力と、前記高周波発生源の出力を設定するための基準電圧とを比較し、当該比較結果に基づいて前記高周波発生源の出力を制御する制御工程とを有することを特徴とする。
上記目的を達成するために、請求項１１記載のプラズマ処理装置は、プラズマ処理容器内に下部電極が配置されたプラズマ処理装置であって、前記下部電極に接続された第１の高周波電源及び第２の高周波電源を備え、前記第１の高周波電源は、前記プラズマ処理容器内にプラズマを生成するための第１の高周波を発生する高周波発生源と、前記第１の高周波を取り出す高周波取り出し手段と、前記第１の高周波と異なる周波数の第２の高周波を発振する発振手段と、前記高周波取り出し手段により取り出された第１の高周波及び前記発振手段により発振された第２の高周波を乗算する乗算手段と、前記乗算手段により乗算された結果から高調波及び変調波の成分を含む高周波分を減衰・除去する高周波減衰手段と、前記高周波減衰手段から出力される１０Ｈｚ〜５００ｋＨｚの範囲の周波数を検波する検波手段と、前記検波手段からの検波出力と、前記高周波発生源の出力を設定するための基準電圧とを比較し、当該比較結果に基づいて前記高周波発生源の出力を制御する制御手段とを備えることを特徴とする。
請求項１２記載のプラズマ処理装置は、請求項１１記載のプラズマ処理装置において、前記高周波発生源が発生する第１の高周波の周波数は、前記第２の高周波電源からの出力の周波数より高い周波数であることを特徴とする。
請求項１３記載のプラズマ処理装置は、請求項１１又は１２記載のプラズマ処理装置において、前記高周波減衰手段からの出力の周波数は、前記第２の高周波電源からの出力の周波数より低い周波数であることを特徴とする。
請求項１４記載のプラズマ処理装置は、請求項１１乃至１３のいずれか１項に記載のプラズマ処理装置において、前記第２の高周波電源は第３の高周波を発生する他の高周波発生源を備え、前記下部電極及び前記他の高周波発生源の間に配置された整合器と、前記下部電極及び前記整合器の間に配置されたローパスフィルタとをさらに備えることを特徴とする。
上記目的を達成するために、請求項１５記載のプラズマ処理装置は、プラズマ処理容器内に下部電極が配置されたプラズマ処理装置であって、前記下部電極に接続された第１の高周波電源と、前記下部電極に接続された、前記第１の高周波電源が出力する第１の高周波の周波数よりも低い周波数の高周波を出力する第２の高周波電源とを備え、前記第１の高周波電源は、前記プラズマ処理容器内にプラズマを生成するための高周波であり、且つ前記第２の高周波電源からの出力の周波数よりも高い周波数である第１の高周波を発生する高周波発生源と、前記第１の高周波を取り出す高周波取り出し手段と、前記第１の高周波と異なる周波数の第２の高周波を発振する発振手段と、前記高周波取り出し手段により取り出された第１の高周波及び前記発振手段により発振された第２の高周波を乗算する乗算手段と、前記乗算手段により乗算された結果から高調波及び変調波の成分を含む高周波分を減衰するローパスフィルタと、前記ローパスフィルタから出力される、前記第２の高周波電源からの出力の周波数よりも低い周波数の出力を検波する検波手段と、前記検波手段からの検波出力と、前記高周波発生源の出力を設定するための基準電圧とを比較し、当該比較結果に基づいて前記高周波発生源の出力を制御する制御手段とを備えることを特徴とする。
請求項１６記載のプラズマ処理装置は、請求項１５記載のプラズマ処理装置において、前記第２の高周波電源は第３の高周波を発生する他の高周波発生源を備え、前記下部電極及び前記他の高周波発生源の間に配置された整合器と、前記下部電極及び前記整合器の間に配置された他のローパスフィルタとをさらに備えることを特徴とする。
請求項１７記載のプラズマ処理装置は、請求項１５又は１６記載のプラズマ処理装置において、前記検波手段は前記ローパスフィルタから出力される１０Ｈｚ〜５００ｋＨｚの範囲の周波数を検波することを特徴とする。
請求項１８記載のプラズマ処理装置は、請求項１５乃至１７のいずれか１項に記載のプラズマ処理装置において、前記検波手段は理想検波器を有しており、当該理想検波器により前記ローパスフィルタからの出力を直流にすることを特徴とする。
【００１３】
【発明の実施の形態】
以下、本発明の実施の形態を図面を参照して詳細に説明する。
【００１４】
図１は、本発明の実施の形態に係る高周波電源を備えるプラズマ処理装置の全体構成を示すブロック図である。
【００１５】
図１において、プラズマ処理装置１は、プラズマ処理容器であるプラズマチャンバ２と、プラズマチャンバ２内の不図示の下部電極に接続された第１のマッチングボックス３と、第１のマッチングボックス３に接続された第１の高周波電源４と、プラズマチャンバ２内の前記電極にローパスフィルタ７を介して接続された第２のマッチングボックス５と、第２のマッチングボックス５に接続された第２の高周波電源６とで構成される。
【００１６】
プラズマ処理装置１は、プラズマチャンバ２内に不図示の一対の平行平板電極（上部電極及び下部電極）を配置して処理ガスを導入すると共に、当該電極の一方に高周波を印加して電極間に高周波電界を形成し、この高周波電界によりプラズマを生成して半導体ウエハ（以下「ウエハ」という。）にプラズマ処理を行う。
【００１７】
第１の高周波電源４は、プラズマチャンバ２に進行する入射波（入射電力：Ｐｆ）及びプラズマ生成時にプラズマチャンバ２から戻ってくる反射波（反射電力：Ｐｒ）を検出して高周波出力を制御するパワーモニタ８と、１００ＭＨｚの高周波を発生する高周波発生源１０とを備え、１００ＭＨｚのプラズマ生成用高周波電力を出力する。また、第１の高周波電源４は、高周波発生源１０から発生した高周波をパワーモニタ８により制御して第１のマッチングボックス３へ出力する。
【００１８】
第１のマッチングボックス３は、１００ＭＨｚの高周波を検波するＲＦセンサ（不図示）と、可変コンデンサ及びコイル等から成る回路（不図示）とを備え、反射波を最も少なくするようにプラズマチャンバ２側の負荷インピーダンスを第１の高周波電源４側の電源インピーダンスに合わせるための整合回路である。特に、第１のマッチングボックス３の入力側からみた負荷インピーダンスと第１の高周波電源４の出力側からみたインピーダンスとが同じ（５０Ω）になるように設定されている。
【００１９】
第２の高周波電源６は、入射波と反射波とを検出して高周波出力を制御するパワーモニタ９と、高周波発生源１０が発生する周波数と異なる３．２ＭＨｚの高周波を発生する高周波発生源１１とを備え、３．２ＭＨｚのバイアス用高周波電力を出力する。
【００２０】
第２のマッチングボックス５は、３．２ＭＨｚの高周波を検波するＲＦセンサ（不図示）と、可変コンデンサ及びコイル等から成る回路（不図示）とを備え、反射波を最も少なくするようにプラズマチャンバ２側の負荷インピーダンスを第２の高周波電源６側の電源インピーダンスに合わせるための整合回路である。ローパスフィルタ７は、第１の高周波電源４からの１００ＭＨｚの高周波から第２のマッチングボックス５及び第２の高周波電源６を保護し、反射波を減衰させるものである。
【００２１】
プラズマ処理時には、第１の高周波電源４により出力されたプラズマ生成用の高周波と、第２の高周波電源６により出力され、プラズマ放電中のイオンを引き込むためのバイアス用の高周波とを重畳したものをプラズマチャンバ２内の下部電極（不図示）に印加する。
【００２２】
図２は、図１におけるパワーモニタ８の内部構成を示す概略図である。
【００２３】
図２において、パワーモニタ８は、方向性結合器２１と、２入力１出力の乗算器（ＤＢＭ：ダブルバランスドミキサー）であるミキサー２２と、１００ｋＨｚのローパスフィルタ２３と、低周波検波器２４と、所定の周波数を発振する発振器２５とを備え、プラズマ生成時に発生する高調波及び変調波を除去して検波を行うと共に、プラズマ生成時に所定の高周波をプラズマチャンバ２に印加する制御装置である。
【００２４】
方向性結合器２１は、高周波発生源１０から発生した１００ＭＨｚの高周波を取り出してミキサー２２に入力する。発振器２５は、増幅器（不図示）や２倍の周波数逓倍器（不図示）、４９．９５ＭＨｚの水晶発振器（不図示）等を備え、ミキサー２２に９９．９ＭＨｚの高周波を入力する。ミキサー２２は、方向性結合器２１により取り出された高周波と発振器２５により入力された高周波とを乗算して周波数混合を行う。ローパスフィルタ２３は、ミキサー２２からの出力のうち高周波分を減衰する。低周波検波器２４は、増幅器（不図示）や１００ｋＨｚの理想検波器（不図示）等を備え、ローパスフィルタ２３からの出力のうち１００ｋＨｚの低周波を検波してＤＣ出力（検波出力）とする。図２のパワーモニタ８における検波（ビートダウン式）と図５における従来の検波（フィルタ式）の周波数特性を図３に示す。
【００２５】
次に、パワーモニタ８の動作について説明する。
【００２６】
例えば、プラズマチャンバ２内のプラズマ負荷の変調により生成された±３．２ＭＨｚのサイドバンド成分を含んだ主周波数１００ＭＨｚの高周波は、方向性結合器２１により取り出されてミキサー２２に入力される。一方、発振器２５からの９９．９ＭＨｚの高周波がミキサー２２に入力される。ミキサー２２では、これらの入力された高周波を乗算し、その結果、１９９．９ＭＨｚ±３．２ＭＨｚ、１００ＭＨｚ＋３．２ＭＨｚ等の信号がローパスフィルタ２３に出力される。
【００２７】
ミキサー２２からの出力のうち、周波数が１９９．９±３．２ＭＨｚや３．２ＭＨｚのものがローパスフィルタ２３により減衰・除去され、低周波検波器２４へ出力される。低周波検波器２４では、ローパスフィルタ２３からの出力である周波数が１００ｋＨｚの低周波をＤＣ出力として誤差増幅回路（不図示）へと出力される。この誤差増幅回路では、低周波検出器からの直流電圧（ＤＣ）と、出力を設定するための基準電圧とを比較して、この比較結果に応じて高周波増幅器（不図示）に比較電圧を与え、出力の制御を行う。これにより、プラズマ生成時に発生した高調波や変調波を精度よく除去して第１の高周波電源４の誤動作を防止すると共に、適正な高周波をプラズマ処理装置１に印加することができる。
【００２８】
主周波数の１００ＭＨｚに対して発振器２５からの周波数を９９．９ＭＨｚに選ぶことで、サイドバンド成分がローパスフィルタ２３のカットオフ周波数から十分離れた周波数となるため、ローパスフィルタ２３が簡易な構成であってもサイドバンド成分を十分に除去することが可能である。また、変調波が主周波数に近い場合であっても、ローパスフィルタ２３のカットオフ周波数を変調周波数に対して十分に低い値に選ぶことで、変調波成分を除去することができる。
【００２９】
上記実施の形態によれば、方向性結合器２１により取り出された変調波等を含む主周波数１００ＭＨｚの高周波と発振器２５により発振された周波数９９．９ＭＨｚの高周波とをミキサー２２により加算し、その出力をローパスフィルタ２３及び低周波検波器２４により１００ｋＨｚに変換して検波を行うので、プラズマ生成時に発生する高調波や変調波を精度よく除去して第１の高周波電源４の誤動作を防止すると共に、適正な高周波をプラズマチャンバ２に印加することができる。
【００３０】
上記実施の形態では、平行平板プラズマ処理装置１について説明したが、例えば、マイクロ波プラズマ処理装置、ＥＣＲ（electron coupling resonance）プラズマ処理装置等の種々のプラズマソースを有するプラズマ処理装置に適応することが可能である。
【００３１】
また、上記実施の形態におけるパワーモニタ８は、１００ＭＨｚの主周波数を１００ｋＨｚに変換して検波を行ったが、それに限られず、１００ＭＨｚ以外、例えば、７０ＭＨｚ以上の主周波数を１００ｋＨｚに変換して検波を行うようにしてもよい。さらに、検波を行う周波数を１００ｋＨｚ以外の周波数、例えば、１０Ｈｚ〜５００ｋＨｚの範囲の周波数にしてもよく、また、制御ループとしての十分速い応答速度を得たい場合には、１５Ｈｚ〜５００ｋＨｚ程度の値に設定するのが望ましい。
【００３２】
なお、上記実施の形態における第１のマッチングボックス３及び第２のマッチングボックス５における整合回路は、可変コンデンサ及びコイルで構成されていたが、例えば、７０ＭＨｚ以上の高周波を印加する場合には、特開２００１−１１８７００号公報に開示された整合器を用いて構成してもよい。
【００３３】
また、パワーモニタ８は、第１の高周波電源４内に内蔵されているが、第１の高周波電源４に代えて第１のマッチングボックス５に内蔵されるようにしてもよく、その場合、検波回路に代えて位相検出回路や演算回路を用い、ＲＦセンサとして使用するようにしてもよい。
【００３４】
【発明の効果】
以上詳細に説明したように、請求項１記載の高周波電源及び請求項１１記載のプラズマ処理装置によれば、高周波取り出し手段により取り出された第１の高周波及び発振手段により発振された第２の高周波を乗算し、乗算された結果から高調波及び変調波の成分を含む高周波分が減衰・除去されて１０Ｈｚ〜５００ｋＨｚの範囲の周波数が検波されるので、プラズマ生成時に発生する高調波や変調波を精度よく除去して誤動作を防止すると共に、適正な高周波を印加することができ、さらに、簡易なフィルタにより高調波や変調波を除去することができる。
また、請求項５記載の高周波電源及び請求項１５記載のプラズマ処理装置によれば、高周波取り出し手段により取り出された第１の高周波及び発振手段により発振された第２の高周波を乗算し、乗算された結果からローパスフィルタにより高調波及び変調波の成分を含む高周波分が減衰されて検波されるので、プラズマ生成時に発生する高調波や変調波を精度よく除去して誤動作を防止すると共に、適正な高周波を印加することができる。
【００３７】
請求項９記載の高周波電源の制御方法によれば、高周波取り出し工程にて取り出された第１の高周波及び発振工程にて発振された第２の高周波を乗算し、乗算された結果から高調波及び変調波の成分を含む高周波分が減衰・除去されて１０Ｈｚ〜５００ｋＨｚの範囲の周波数が検波されるので、プラズマ生成時に発生する高調波や変調波を精度よく除去して誤動作を防止すると共に、適正な高周波を印加することができ、さらに、簡易なフィルタにより高調波や変調波を除去することができる。
また、請求項１０記載の高周波電源の制御方法によれば、高周波取り出し工程にて取り出された第１の高周波及び発振工程にて発振された第２の高周波を乗算し、乗算された結果からローパスフィルタにより高調波及び変調波の成分を含む高周波分が減衰されて検波されるので、プラズマ生成時に発生する高調波や変調波を精度よく除去して誤動作を防止すると共に、適正な高周波を印加することができる。
【図面の簡単な説明】
【図１】本発明の実施の形態に係る高周波電源を備えるプラズマ処理装置の全体構成を示すブロック図である。
【図２】図１におけるパワーモニタ８の内部構成を示す概略図である。
【図３】図２のパワーモニタ８における検波（ビートダウン式）と図５における従来の検波（フィルタ式）の周波数特性を示す図である。
【図４】従来のプラズマ処理装置における入出力の変調波スペクトルを示す図であり、（ａ）は入射波、（ｂ）は反射波である。
【図５】従来のプラズマ処理装置におけるパワーモニタの内部構成を示す概略図である。
【符号の説明】
１プラズマ処理装置
２プラズマチャンバ
３第１のマッチングボックス
４第１の高周波電源
５第２のマッチングボックス
６第２の高周波電源
７ローパスフィルタ
８，９パワーモニタ
１０，１１高周波発生源
２１方向性結合器
２２ミキサー
２３ローパスフィルタ
２４低周波検波器
２５発振器[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a high frequency power supply and a control method thereof. And plasma processing apparatus In particular, the present invention relates to a high-frequency power source of a plasma processing apparatus that performs plasma processing on a semiconductor wafer and a control method thereof.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, in a semiconductor device manufacturing process, a plasma processing apparatus that generates high-density plasma in a relatively low-pressure atmosphere and performs etching on a semiconductor wafer (hereinafter simply referred to as “wafer”) is used. For example, in a parallel plate plasma processing apparatus, a pair of parallel plate electrodes (upper and lower electrodes) are arranged in a plasma chamber, a processing gas is introduced into the chamber, and a high frequency is applied to one of the electrodes to provide a gap between the electrodes. A high-frequency electric field is generated at this time, and plasma of a processing gas is generated by this high-frequency electric field to etch the wafer.
[0003]
In such a plasma processing apparatus, in order to perform etching efficiently, a high frequency for plasma generation and a high frequency for bias for drawing ions in the plasma are superimposed and simultaneously applied to the lower electrode. Specifically, a high frequency power source for plasma generation is connected to the lower electrode via a matching circuit (hereinafter referred to as “matching box”), and a high frequency power source for bias is connected to the lower electrode via a matching box. Two high frequencies are superimposed. The high frequency for plasma generation is set to a frequency of 100 MHz in consideration of plasma generation efficiency, while the high frequency for bias is set to a frequency of 3.2 MHz.
[0004]
In the plasma processing apparatus, during the plasma processing, harmonics and modulation waves corresponding to the main frequencies of 100 MHz and 3.2 MHz are generated, and these harmonics and modulation waves are in the vicinity of the main frequency of the incident wave (Pf). (FIG. 4 (a)) and also appears in the vicinity of the main frequency of the reflected wave (Pr) (FIG. 4 (b)), causing a malfunction or the like in the matching box or the high-frequency power source. Therefore, the high-frequency power source includes a power monitor that detects incident waves and reflected waves and controls high-frequency output, and the power monitor uses a detection circuit (FIG. 5) including a band-pass filter composed of an LC circuit to generate harmonics. And modulation waves are removed.
[0005]
[Problems to be solved by the invention]
However, in the high-frequency power supply including the conventional bandpass filter, when the frequency difference between the plasma generation high frequency and the bias high frequency, which is an incident wave, increases, the main frequency included in the reflected wave and the frequency of the modulation wave, etc. The difference is reduced, and the band-pass filter composed of the LC circuit cannot sufficiently attenuate the modulated wave, and as a result, the modulated wave is regarded as a reflected wave, which may cause the high-frequency power supply to malfunction. .
[0006]
Further, if the modulation wave or the like cannot be sufficiently attenuated, it is difficult to apply an appropriate high frequency during plasma processing.
[0007]
The present invention has been made in view of the above-described problems, and removes harmonics and modulated waves generated during plasma generation with high accuracy to prevent malfunctions and to achieve appropriate high frequency. Mark High frequency power supply that can be applied and control method thereof And plasma processing apparatus The purpose is to provide.
[0008]
[Means for Solving the Problems]
In order to achieve the above object, the high frequency power supply according to claim 1 is a high frequency power supply for a plasma processing apparatus in which a lower electrode is disposed in a plasma processing container, and the first high frequency power supply connected to the lower electrode. And a second high-frequency power source The first high-frequency power source includes a high-frequency generation source that generates a first high-frequency for generating plasma in the plasma processing vessel, a high-frequency extraction unit that extracts the first high-frequency, and the first Oscillation means for oscillating a second high frequency having a frequency different from the high frequency of the first frequency, multiplication means for multiplying the first high frequency extracted by the high frequency extraction means and the second high frequency oscillated by the oscillation means, and the multiplication From the result multiplied by means Includes harmonic and modulated wave components Attenuates high frequency components ·Removal High frequency attenuating means, and a detecting means for detecting a frequency in the range of 10 Hz to 500 kHz outputted from the high frequency attenuating means And a control means for comparing the detection output from the detection means with a reference voltage for setting the output of the high-frequency generation source and controlling the output of the high-frequency generation source based on the comparison result It is characterized by that.
The high-frequency power source according to claim 2 is the high-frequency power source according to claim 1, wherein the frequency of the first high-frequency generated by the high-frequency generation source is higher than the frequency of the output from the second high-frequency power source. It is characterized by.
The high-frequency power source according to claim 3 is the high-frequency power source according to claim 1 or 2, wherein the frequency of the output from the high-frequency attenuation means is lower than the frequency of the output from the second high-frequency power source. And
The high-frequency power source according to claim 4 is the high-frequency power source according to any one of claims 1 to 3, wherein the second high-frequency power source includes another high-frequency generation source that generates a third high frequency, and the lower portion A matching device is disposed between the electrode and the other high-frequency generation source, and a low-pass filter is disposed between the lower electrode and the matching device.
In order to achieve the above object, the high frequency power supply according to claim 5 is a high frequency power supply for a plasma processing apparatus in which a lower electrode is disposed in a plasma processing container, and the first high frequency power supply connected to the lower electrode. And a second high-frequency power source connected to the lower electrode and outputting a high frequency having a frequency lower than the first high-frequency frequency output by the first high-frequency power source. The first high-frequency power source includes a high-frequency generation source that generates a first high-frequency for generating plasma in the plasma processing vessel, a high-frequency extraction unit that extracts the first high-frequency, and the first Oscillation means for oscillating a second high frequency having a frequency different from the high frequency of the first frequency, multiplication means for multiplying the first high frequency extracted by the high frequency extraction means and the second high frequency oscillated by the oscillation means, and the multiplication From the result multiplied by means Includes harmonic and modulated wave components From a low-pass filter that attenuates high-frequency components and the low-pass filter The output frequency is lower than the frequency of the output from the second high frequency power supply Detection means to detect the output of And a control means for comparing the detection output from the detection means with a reference voltage for setting the output of the high-frequency generation source and controlling the output of the high-frequency generation source based on the comparison result It is characterized by that.
6. The high frequency power supply according to claim 6, wherein the second high frequency power supply includes another high frequency generation source for generating a third high frequency, and the lower electrode and the other high frequency generation source. A matching device is disposed between the lower electrode and the matching device, and another low-pass filter is disposed between the lower electrode and the matching device.
The high frequency power supply according to claim 7 is the high frequency power supply according to claim 5 or 6, wherein the detection means detects a frequency in a range of 10 Hz to 500 kHz output from the low pass filter.
The high-frequency power supply according to claim 8 is the high-frequency power supply according to any one of claims 5 to 7, wherein the detection means has an ideal detector, and an output from the low-pass filter by the ideal detector. Is a direct current.
[0012]
In order to achieve the above object, a high frequency power supply control method according to claim 9 is a high frequency power supply control method for a plasma processing apparatus in which a lower electrode is disposed in a plasma processing container, wherein the high frequency power supply includes First high-frequency power source connected to the lower electrode And a second high-frequency power source The first high-frequency power source includes a high-frequency generation source that generates a first high-frequency for generating plasma in the plasma processing container, and a high-frequency extraction step for extracting the first high-frequency, and the first An oscillation step of oscillating a second high frequency different from the first high frequency, a multiplication step of multiplying the first high frequency extracted in the high frequency extraction step and the second high frequency oscillated in the oscillation step, From the result of multiplication in the multiplication step Includes harmonic and modulated wave components Attenuates high frequency components ·Removal And a detection step of detecting a frequency in the range of 10 Hz to 500 kHz output after the high frequency attenuation step And a control step of comparing the detection output after the detection step with a reference voltage for setting the output of the high-frequency generation source and controlling the output of the high-frequency generation source based on the comparison result It is characterized by that.
In order to achieve the above object, a high frequency power supply control method according to claim 10 is a high frequency power supply control method for a plasma processing apparatus in which a lower electrode is disposed in a plasma processing vessel, wherein the high frequency power supply includes First high-frequency power source connected to the lower electrode And a second high-frequency power source connected to the lower electrode and outputting a high frequency having a frequency lower than the first high-frequency frequency output by the first high-frequency power source. The first high-frequency power source includes a high-frequency generation source that generates a first high-frequency for generating plasma in the plasma processing container, and a high-frequency extraction step for extracting the first high-frequency, and the first An oscillation step of oscillating a second high frequency different from the first high frequency, a multiplication step of multiplying the first high frequency extracted in the high frequency extraction step and the second high frequency oscillated in the oscillation step, From the result of multiplication in the multiplication step Includes harmonic and modulated wave components A high frequency attenuation process for attenuating a high frequency component with a low-pass filter and output in the high frequency attenuation process A frequency lower than the frequency of the output from the second high-frequency power source. Detection process for detecting output And a control step of comparing the detection output after the detection step with a reference voltage for setting the output of the high-frequency generation source and controlling the output of the high-frequency generation source based on the comparison result It is characterized by that.
In order to achieve the above object, a plasma processing apparatus according to claim 11 is a plasma processing apparatus in which a lower electrode is disposed in a plasma processing container, wherein a first high-frequency power source connected to the lower electrode, Two high-frequency power sources, wherein the first high-frequency power source includes a high-frequency generation source that generates a first high frequency for generating plasma in the plasma processing vessel, and a high-frequency extraction unit that extracts the first high frequency. Oscillating means for oscillating a second high frequency different from the first high frequency, and multiplying means for multiplying the first high frequency extracted by the high frequency extracting means and the second high frequency oscillated by the oscillating means. And from the result of multiplication by the multiplication means Includes harmonic and modulated wave components Attenuates high frequency components ·Removal High frequency attenuating means, and a detecting means for detecting a frequency in the range of 10 Hz to 500 kHz outputted from the high frequency attenuating means And a control means for comparing the detection output from the detection means with a reference voltage for setting the output of the high-frequency generation source and controlling the output of the high-frequency generation source based on the comparison result It is characterized by that.
The plasma processing apparatus according to claim 12 is the plasma processing apparatus according to claim 11, wherein the frequency of the first high frequency generated by the high frequency generation source is higher than the frequency of the output from the second high frequency power supply. It is characterized by being.
The plasma processing apparatus according to claim 13 is the plasma processing apparatus according to claim 11 or 12, wherein the frequency of the output from the high frequency attenuation means is lower than the frequency of the output from the second high frequency power supply. It is characterized by.
The plasma processing apparatus according to claim 14 is the plasma processing apparatus according to any one of claims 11 to 13, wherein the second high-frequency power source includes another high-frequency generation source that generates a third high-frequency, The apparatus further includes a matching unit disposed between the lower electrode and the other high-frequency generation source, and a low-pass filter disposed between the lower electrode and the matching unit.
In order to achieve the above object, the plasma processing apparatus according to claim 15 is a plasma processing apparatus in which a lower electrode is disposed in a plasma processing container, and the first high-frequency power source connected to the lower electrode And outputs a high frequency having a frequency lower than the first high frequency output from the first high frequency power source connected to the lower electrode. Second high frequency power supply When The first high-frequency power source is a high-frequency for generating plasma in the plasma processing vessel, and the first high-frequency power is higher than the frequency of the output from the second high-frequency power source. A high-frequency generation source for generating, a high-frequency extraction means for extracting the first high frequency, an oscillating means for oscillating a second high frequency different from the first high frequency, and a first extracted by the high-frequency extraction means Multiplying means for multiplying the high frequency and the second high frequency oscillated by the oscillating means, and the result multiplied by the multiplying means Includes harmonic and modulated wave components From a low-pass filter that attenuates high-frequency components and the low-pass filter The output frequency is lower than the frequency of the output from the second high frequency power supply Detection means to detect the output of And a control means for comparing the detection output from the detection means with a reference voltage for setting the output of the high-frequency generation source and controlling the output of the high-frequency generation source based on the comparison result It is characterized by that.
The plasma processing apparatus according to claim 16 is the plasma processing apparatus according to claim 15, wherein the second high-frequency power source includes another high-frequency generation source that generates a third high-frequency, and the lower electrode and the other high-frequency generation source. It further comprises a matching unit disposed between the generation sources, and another low-pass filter disposed between the lower electrode and the matching unit.
The plasma processing apparatus according to claim 17 is the plasma processing apparatus according to claim 15 or 16, wherein the detection means detects a frequency in a range of 10 Hz to 500 kHz output from the low-pass filter.
The plasma processing apparatus according to claim 18 is the plasma processing apparatus according to any one of claims 15 to 17, wherein the detection means includes an ideal detector, and the ideal detector detects the low-pass filter. Is characterized in that the output is DC.
[0013]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
[0014]
FIG. 1 is a block diagram showing an overall configuration of a plasma processing apparatus including a high frequency power source according to an embodiment of the present invention.
[0015]
In FIG. 1, a plasma processing apparatus 1 is connected to a plasma chamber 2 that is a plasma processing container, a first matching box 3 connected to a lower electrode (not shown) in the plasma chamber 2, and a first matching box 3. First high-frequency power source 4, a second matching box 5 connected to the electrode in the plasma chamber 2 via a low-pass filter 7, and a second high-frequency power source connected to the second matching box 5 6.
[0016]
The plasma processing apparatus 1 arranges a pair of parallel plate electrodes (not shown) (upper electrode and lower electrode) in the plasma chamber 2 to introduce a processing gas, and applies a high frequency to one of the electrodes to apply a gap between the electrodes. A high frequency electric field is formed, plasma is generated by the high frequency electric field, and a semiconductor wafer (hereinafter referred to as “wafer”) is subjected to plasma treatment.
[0017]
The first high-frequency power source 4 detects an incident wave (incident power: Pf) traveling to the plasma chamber 2 and a reflected wave (reflected power: Pr) returning from the plasma chamber 2 when plasma is generated to control the high-frequency output. A power monitor 8 and a high frequency generation source 10 that generates a high frequency of 100 MHz are provided, and a high frequency power for plasma generation of 100 MHz is output. Further, the first high frequency power source 4 controls the high frequency generated from the high frequency generation source 10 by the power monitor 8 and outputs it to the first matching box 3.
[0018]
The first matching box 3 includes an RF sensor (not shown) that detects a high frequency of 100 MHz and a circuit (not shown) that includes a variable capacitor, a coil, and the like, and has a plasma chamber 2 side that minimizes reflected waves. Is a matching circuit for matching the load impedance to the power impedance on the first high-frequency power source 4 side. In particular, the load impedance viewed from the input side of the first matching box 3 and the impedance viewed from the output side of the first high-frequency power supply 4 are set to be the same (50Ω).
[0019]
The second high-frequency power source 6 includes a power monitor 9 that detects incident waves and reflected waves and controls high-frequency output, and a high-frequency generation source 11 that generates a high frequency of 3.2 MHz different from the frequency generated by the high-frequency generation source 10. And outputs a bias high frequency power of 3.2 MHz.
[0020]
The second matching box 5 includes an RF sensor (not shown) for detecting a high frequency of 3.2 MHz and a circuit (not shown) made up of a variable capacitor, a coil and the like, and a plasma chamber so as to minimize reflected waves. This is a matching circuit for matching the load impedance on the second side with the power source impedance on the second high-frequency power source 6 side. The low-pass filter 7 protects the second matching box 5 and the second high-frequency power source 6 from a high frequency of 100 MHz from the first high-frequency power source 4 and attenuates reflected waves.
[0021]
At the time of plasma processing, a plasma generation high frequency output from the first high frequency power supply 4 and a bias high frequency output from the second high frequency power supply 6 for drawing ions in the plasma discharge are superimposed. The voltage is applied to a lower electrode (not shown) in the plasma chamber 2.
[0022]
FIG. 2 is a schematic diagram showing the internal configuration of the power monitor 8 in FIG.
[0023]
In FIG. 2, the power monitor 8 includes a directional coupler 21, a mixer 22 that is a 2-input 1-output multiplier (DBM: double balanced mixer), a 100 kHz low-pass filter 23, and a low-frequency detector 24. The control device includes an oscillator 25 that oscillates at a predetermined frequency, and performs detection by removing harmonics and modulation waves generated during plasma generation, and applies a predetermined high frequency to the plasma chamber 2 during plasma generation.
[0024]
The directional coupler 21 takes out a high frequency of 100 MHz generated from the high frequency generation source 10 and inputs it to the mixer 22. The oscillator 25 includes an amplifier (not shown), a double frequency multiplier (not shown), a 49.95 MHz crystal oscillator (not shown), and the like, and inputs a high frequency of 99.9 MHz to the mixer 22. The mixer 22 multiplies the high frequency extracted by the directional coupler 21 and the high frequency input by the oscillator 25 to perform frequency mixing. The low pass filter 23 attenuates the high frequency component of the output from the mixer 22. The low-frequency detector 24 includes an amplifier (not shown), an ideal detector (not shown) of 100 kHz, and the like, and detects a low frequency of 100 kHz among outputs from the low-pass filter 23 to obtain a DC output (detection output). . FIG. 3 shows frequency characteristics of detection (beat down type) in the power monitor 8 of FIG. 2 and conventional detection (filter type) in FIG.
[0025]
Next, the operation of the power monitor 8 will be described.
[0026]
For example, a high frequency with a main frequency of 100 MHz including a side band component of ± 3.2 MHz generated by modulation of the plasma load in the plasma chamber 2 is taken out by the directional coupler 21 and input to the mixer 22. On the other hand, a high frequency of 99.9 MHz from the oscillator 25 is input to the mixer 22. The mixer 22 multiplies these input high frequencies, and as a result, a signal of 199.9 MHz ± 3.2 MHz, 100 MHz + 3.2 MHz, or the like is output to the low-pass filter 23.
[0027]
Among the outputs from the mixer 22, those having a frequency of 199.9 ± 3.2 MHz or 3.2 MHz are attenuated and removed by the low-pass filter 23 and output to the low-frequency detector 24. The low frequency detector 24 outputs a low frequency of 100 kHz, which is an output from the low pass filter 23, as a DC output to an error amplifier circuit (not shown). In this error amplification circuit, a direct current voltage (DC) from a low frequency detector is compared with a reference voltage for setting an output, and a comparison voltage is applied to a high frequency amplifier (not shown) according to the comparison result. Control the output. Thereby, harmonics and modulation waves generated during plasma generation can be accurately removed to prevent malfunction of the first high-frequency power supply 4 and an appropriate high frequency can be applied to the plasma processing apparatus 1.
[0028]
By selecting the frequency from the oscillator 25 to 99.9 MHz with respect to the main frequency of 100 MHz, the sideband component becomes a frequency sufficiently separated from the cutoff frequency of the low-pass filter 23, so the low-pass filter 23 has a simple configuration. However, the sideband component can be sufficiently removed. Even if the modulation wave is close to the main frequency, the modulation wave component can be removed by selecting the cutoff frequency of the low-pass filter 23 to a value sufficiently lower than the modulation frequency.
[0029]
According to the above embodiment, the mixer 22 adds the high frequency of the main frequency 100 MHz including the modulated wave extracted by the directional coupler 21 and the high frequency of the frequency 99.9 MHz oscillated by the oscillator 25, and outputs the result. Is converted to 100 kHz by the low-pass filter 23 and the low-frequency detector 24 to perform detection, so that harmonics and modulation waves generated at the time of plasma generation can be accurately removed to prevent malfunction of the first high-frequency power source 4. An appropriate high frequency can be applied to the plasma chamber 2.
[0030]
Although the parallel plate plasma processing apparatus 1 has been described in the above embodiment, it can be applied to plasma processing apparatuses having various plasma sources such as a microwave plasma processing apparatus and an ECR (electron coupling resonance) plasma processing apparatus. Is possible.
[0031]
Further, the power monitor 8 in the above embodiment converts the main frequency of 100 MHz to 100 kHz and performs detection. However, the present invention is not limited to this, and other than 100 MHz, for example, the main frequency of 70 MHz or more is converted to 100 kHz and detected. You may make it perform. Furthermore, the frequency for detection may be set to a frequency other than 100 kHz, for example, a frequency in the range of 10 Hz to 500 kHz. If a sufficiently fast response speed as a control loop is desired, the value is set to a value of about 15 Hz to 500 kHz. It is desirable to set.
[0032]
Note that the matching circuit in the first matching box 3 and the second matching box 5 in the above embodiment is configured with a variable capacitor and a coil. However, for example, when a high frequency of 70 MHz or more is applied, a special circuit is used. You may comprise using the matching device disclosed by the open 2001-118700 gazette.
[0033]
Further, although the power monitor 8 is built in the first high frequency power supply 4, it may be built in the first matching box 5 instead of the first high frequency power supply 4. Instead of the circuit, a phase detection circuit or an arithmetic circuit may be used and used as an RF sensor.
[0034]
【The invention's effect】
As described above in detail, according to the high frequency power source of claim 1 and the plasma processing apparatus of claim 11, the first high frequency extracted by the high frequency extraction means and the second high frequency oscillated by the oscillation means. And from the multiplied result Includes harmonic and modulated wave components High frequency component attenuated ·Removal Since a frequency in the range of 10 Hz to 500 kHz is detected, harmonics and modulation waves generated during plasma generation can be accurately removed to prevent malfunction, and an appropriate high frequency can be applied. Harmonics and modulated waves can be removed with a simple filter.
According to the high frequency power source of claim 5 and the plasma processing apparatus of claim 15, the first high frequency extracted by the high frequency extraction means and the second high frequency oscillated by the oscillation means are multiplied and multiplied. From the result of the low pass filter Includes harmonic and modulated wave components Since the high frequency component is attenuated and detected, harmonics and modulated waves generated during plasma generation can be accurately removed to prevent malfunction and an appropriate high frequency can be applied.
[0037]
According to the method for controlling a high frequency power supply according to claim 9, the first high frequency extracted in the high frequency extraction step and the second high frequency oscillated in the oscillation step are multiplied and the result of multiplication is used. Includes harmonic and modulated wave components High frequency component attenuated ·Removal Since a frequency in the range of 10 Hz to 500 kHz is detected, harmonics and modulation waves generated during plasma generation can be accurately removed to prevent malfunction, and an appropriate high frequency can be applied. Harmonics and modulated waves can be removed with a simple filter.
According to the method for controlling a high frequency power supply according to claim 10, the first high frequency extracted in the high frequency extraction step and the second high frequency oscillated in the oscillation step are multiplied, and a low pass is determined from the multiplication result. By filter Includes harmonic and modulated wave components Since the high frequency component is attenuated and detected, harmonics and modulated waves generated during plasma generation can be accurately removed to prevent malfunction and an appropriate high frequency can be applied.
[Brief description of the drawings]
FIG. 1 is a block diagram showing an overall configuration of a plasma processing apparatus including a high frequency power supply according to an embodiment of the present invention.
2 is a schematic diagram showing an internal configuration of a power monitor 8 in FIG.
3 is a diagram showing frequency characteristics of detection (beat-down type) in the power monitor 8 of FIG. 2 and conventional detection (filter type) in FIG. 5;
FIGS. 4A and 4B are diagrams showing input / output modulated wave spectra in a conventional plasma processing apparatus, where FIG. 4A shows an incident wave and FIG. 4B shows a reflected wave;
FIG. 5 is a schematic diagram showing an internal configuration of a power monitor in a conventional plasma processing apparatus.
[Explanation of symbols]
1 Plasma processing equipment
2 Plasma chamber
3 First matching box
4 First high frequency power supply
5 Second matching box
6 Second high-frequency power supply
7 Low-pass filter
8,9 Power monitor
10, 11 High frequency source
21 Directional coupler
22 Mixer
23 Low-pass filter
24 Low frequency detector
25 Oscillator

Claims

A high-frequency power supply for a plasma processing apparatus in which a lower electrode is disposed in a plasma processing container,
A first high-frequency power source and a second high-frequency power source connected to the lower electrode;
The first high frequency power source is:
A high frequency generation source for generating a first high frequency for generating plasma in the plasma processing vessel;
A high frequency extraction means for extracting the first high frequency;
Oscillating means for oscillating a second high frequency different from the first high frequency;
Multiplying means for multiplying the first high frequency extracted by the high frequency extracting means and the second high frequency oscillated by the oscillating means;
High-frequency attenuation means for attenuating and removing high-frequency components including harmonic and modulated wave components from the result of multiplication by the multiplication means;
Detection means for detecting a frequency in the range of 10 Hz to 500 kHz output from the high-frequency attenuation means ;
Control means for comparing the detection output from the detection means with a reference voltage for setting the output of the high-frequency generation source, and controlling the output of the high-frequency generation source based on the comparison result. And high frequency power supply.

2. The high frequency power supply according to claim 1, wherein a frequency of the first high frequency generated by the high frequency generation source is higher than a frequency of an output from the second high frequency power supply.

The high frequency power supply according to claim 1 or 2, wherein the frequency of the output from the high frequency attenuating means is lower than the frequency of the output from the second high frequency power supply.

The second high-frequency power source includes another high-frequency generation source that generates a third high-frequency, a matching unit is disposed between the lower electrode and the other high-frequency generation source, and the lower electrode and the matching unit The high frequency power supply according to any one of claims 1 to 3, wherein a low-pass filter is disposed therebetween.

A high-frequency power supply for a plasma processing apparatus in which a lower electrode is disposed in a plasma processing container,
A first high-frequency power source connected to the lower electrode ;
A second high frequency power source connected to the lower electrode and outputting a high frequency of a frequency lower than the first high frequency frequency output by the first high frequency power source ,
The first high frequency power source is:
A high frequency generation source for generating a first high frequency for generating plasma in the plasma processing vessel;
A high frequency extraction means for extracting the first high frequency;
Oscillating means for oscillating a second high frequency different from the first high frequency;
Multiplying means for multiplying the first high frequency extracted by the high frequency extracting means and the second high frequency oscillated by the oscillating means;
A low-pass filter for attenuating high-frequency components including harmonic and modulated wave components from the result of multiplication by the multiplication means;
Detection means for detecting an output having a frequency lower than that of the output from the second high-frequency power source, which is output from the low-pass filter ;
Control means for comparing the detection output from the detection means with a reference voltage for setting the output of the high-frequency generation source, and controlling the output of the high-frequency generation source based on the comparison result. And high frequency power supply.

The second high-frequency power source includes another high-frequency generation source that generates a third high-frequency, a matching unit is disposed between the lower electrode and the other high-frequency generation source, and the lower electrode and the matching unit 6. The high-frequency power source according to claim 5, wherein another low-pass filter is disposed between them.

7. The high frequency power supply according to claim 5, wherein the detection means detects a frequency in a range of 10 Hz to 500 kHz output from the low pass filter.

The high-frequency power supply according to any one of claims 5 to 7, wherein the detection means includes an ideal detector, and the output from the low-pass filter is converted into a direct current by the ideal detector.

A method for controlling a high frequency power source of a plasma processing apparatus in which a lower electrode is disposed in a plasma processing container,
The high frequency power source includes a first high frequency power source and a second high frequency power source connected to the lower electrode,
The first high frequency power source includes a high frequency generation source that generates a first high frequency for generating plasma in the plasma processing vessel,
A high frequency extraction step of extracting the first high frequency;
An oscillation step of oscillating a second high frequency having a frequency different from the first high frequency;
A multiplication step of multiplying the first high frequency extracted in the high frequency extraction step and the second high frequency oscillated in the oscillation step;
A high-frequency attenuation step for attenuating and removing high-frequency components including harmonic and modulated wave components from the result of multiplication in the multiplication step;
A detection step of detecting a frequency in the range of 10 Hz to 500 kHz output after the high-frequency attenuation step ;
A control step of comparing the detection output after the detection step with a reference voltage for setting the output of the high-frequency generation source, and controlling the output of the high-frequency generation source based on the comparison result. A method for controlling a high-frequency power source.

A method for controlling a high frequency power source of a plasma processing apparatus in which a lower electrode is disposed in a plasma processing container,
The high frequency power source outputs a first high frequency power source connected to the lower electrode and a high frequency having a frequency lower than a first high frequency frequency output from the first high frequency power source connected to the lower electrode. And a second high frequency power source
The first high frequency power source includes a high frequency generation source that generates a first high frequency for generating plasma in the plasma processing vessel,
A high frequency extraction step of extracting the first high frequency;
An oscillation step of oscillating a second high frequency having a frequency different from the first high frequency;
A multiplication step of multiplying the first high frequency extracted in the high frequency extraction step and the second high frequency oscillated in the oscillation step;
A high-frequency attenuation step of attenuating a high-frequency component including harmonic and modulated wave components from the result multiplied in the multiplication step by a low-pass filter;
A detection step of detecting an output having a frequency lower than the frequency of the output from the second high-frequency power source, which is output in the high-frequency attenuation step ;
A control step of comparing the detection output after the detection step with a reference voltage for setting the output of the high-frequency generation source, and controlling the output of the high-frequency generation source based on the comparison result. A method for controlling a high-frequency power source.

A plasma processing apparatus in which a lower electrode is disposed in a plasma processing container,
A first high-frequency power source and a second high-frequency power source connected to the lower electrode;
The first high frequency power source is:
A high frequency generation source for generating a first high frequency for generating plasma in the plasma processing vessel;
A high frequency extraction means for extracting the first high frequency;
Oscillating means for oscillating a second high frequency different from the first high frequency;
Multiplying means for multiplying the first high frequency extracted by the high frequency extracting means and the second high frequency oscillated by the oscillating means;
High-frequency attenuation means for attenuating and removing high-frequency components including harmonic and modulated wave components from the result of multiplication by the multiplication means;
Detection means for detecting a frequency in the range of 10 Hz to 500 kHz output from the high-frequency attenuation means ;
Control means for comparing the detection output from the detection means with a reference voltage for setting the output of the high-frequency generation source, and controlling the output of the high-frequency generation source based on the comparison result. A plasma processing apparatus.

12. The plasma processing apparatus according to claim 11, wherein the frequency of the first high frequency generated by the high frequency generation source is higher than the frequency of the output from the second high frequency power source.

13. The plasma processing apparatus according to claim 11, wherein the frequency of the output from the high frequency attenuation means is lower than the frequency of the output from the second high frequency power source.

The second high-frequency power source includes another high-frequency generation source that generates a third high-frequency power source, and includes a matching unit disposed between the lower electrode and the other high-frequency generation source, and the lower electrode and the matching unit. The plasma processing apparatus according to claim 11, further comprising a low-pass filter disposed therebetween.

A plasma processing apparatus in which a lower electrode is disposed in a plasma processing container,
A first high-frequency power source connected to the lower electrode ;
Connected to said lower electrode, and a second RF power supply that outputs a high frequency of the first first frequency lower than the frequency of the high frequency RF power is output,
The first high frequency power source is:
A high frequency generating source that generates a first high frequency that is a high frequency for generating plasma in the plasma processing vessel and that is higher than a frequency of an output from the second high frequency power supply;
A high frequency extraction means for extracting the first high frequency;
Oscillating means for oscillating a second high frequency different from the first high frequency;
Multiplying means for multiplying the first high frequency extracted by the high frequency extracting means and the second high frequency oscillated by the oscillating means;
A low-pass filter for attenuating high-frequency components including harmonic and modulated wave components from the result of multiplication by the multiplication means;
Detection means for detecting an output having a frequency lower than that of the output from the second high-frequency power source, which is output from the low-pass filter ;
Control means for comparing the detection output from the detection means with a reference voltage for setting the output of the high-frequency generation source, and controlling the output of the high-frequency generation source based on the comparison result. A plasma processing apparatus.

The second high-frequency power source includes another high-frequency generation source that generates a third high-frequency power source, and includes a matching unit disposed between the lower electrode and the other high-frequency generation source, and the lower electrode and the matching unit. The plasma processing apparatus according to claim 15, further comprising another low-pass filter disposed therebetween.

The plasma processing apparatus according to claim 15 or 16, wherein the detection means detects a frequency in a range of 10 Hz to 500 kHz output from the low-pass filter.

The plasma processing apparatus according to any one of claims 15 to 17, wherein the detection means includes an ideal detector, and the output from the low-pass filter is converted into a direct current by the ideal detector.