JP4478352B2 - Plasma processing apparatus, plasma processing method, and structure manufacturing method - Google Patents

Description

【０１０６】
プラズマの発生及び処理は以下のようにして行なう。
先ず、排気手段１８を介してプラズマ処理室を真空排気する。
続いて、プラズマ処理ガスを処理ガス供給口７を介して所定の流量でプラズマ処理室に導入する。
【０１０７】
次に、プラズマ処理室と排気ポンプ１８との間に設けられたコンダクタンス調整手段２８を調整し、プラズマ処理室を所定の圧力に保持する。必要に応じて、高周波バイアス印加手段２２を介して被処理体Ｗにバイアスを印加する。マイクロ波電源ＭＷより所望の電力を無終端環状導波路１３を介してプラズマ処理室に供給する。
【０１０８】
この際、無終端環状導波路１３内に導入されたＴＥ₁₀モードのマイクロ波は、導入口１５のＥ分岐で左右に二分配され、自由空間よりも長い路内波長をもって導波路１３内を伝搬する。分配されたマイクロ波同士は干渉しあい、管内波長の１／２毎に“腹”をもつ定在波ＳＴＷを生じる。導波管の導電性の面、ここではＨ面を流れる電流が最大になる位置、即ち、隣接する２つの“腹”間の中央に設置されたスロット３３から誘電体窓４を透してプラズマ処理室に導入されたマイクロ波は、スロット３３近傍にプラズマを生成する。生成したプラズマの電子プラズマ周波数が電源周波数を超える（例えば、電子密度が７×１０¹⁰／ｃｍ³を超える場合、電子プラズマ周波数が電源周波数２．４５ＧＨｚを超える）と、マイクロ波はプラズマ中を伝搬できなくなり（いわゆるカットオフ）、更に電子密度が増加し、
δ＝（２／ωμ₀σ）^1/2
［ω：電源角周波数、μ₀：真空透磁率、σ：プラズマ導電率］
で表される表皮厚が十分薄くなる（例えば、電子密度が２×１０¹²ｃｍ^-3以上になると、表皮厚は４ｍｍ以下になる）と、誘電体窓４の表面を表面波ＳＷとして伝搬する。
【０１０９】
隣接するスロット３３から導入された表面波ＳＷ同士が干渉し、略、
λ₅＝λ₀ε_r ^-1/2
［λ₀：自由空間マイクロ波波長、ε_r：誘電体比誘電率］
で表される表面波ＳＷの波長の１／２毎に表面定在波ＳＳＴＷを生じる。
【０１１０】
プラズマ処理室にしみ出したこの表面定在波ＳＳＴＷによって電子が加速され表面波干渉プラズマ（ＳＩＰ：Ｓｕｒｆａｃｅ−ｗａｖｅ Ｉｎｔｅｒｆｅｒｅｄ Ｐｌａｓｍａ）が生成される。この時に処理ガス供給口７を介して処理ガスをプラズマ処理室に導入しておくと、処理ガスは発生した高密度プラズマにより励起され、支持体２上に載置された被処理体Ｗの表面を処理する。
【０１１１】
本実施形態のマイクロ波プラズマ処理装置に用いられるスロット３３の形状は、スロット３３の中心が略、
ｒ_e＝ｎ₁λ₅／｛２ｔａｎ（π／（２ｎ_g））｝｛１＋ｃｏｓ（π／ｎ_g）｝
で表される位置Ｃ２に存在するのであれば、長さが管内波長の１／４から３／８である矩形状穿孔でなくても適用可能である。
【０１１２】
（第２の実施形態）
本発明のマイクロ波プラズマ処理装置において、ｎ_gが３、スロット間表面定在波個数ｎ₁が３、誘電体が石英ガラス（誘電率ε_r：３．８）の場合のマイクロ波供給器を図１８に示す。装置本体の構成は図１６（ａ）等とほぼ同じである。
【０１１３】
ここでは、スロット３３は、無終端環状導波管内のマイクロ波導波路１３の中央より外側の、半径が略１０３．９ｍｍである円周Ｃ５上にスロットの中心が存在するように形成されている。
【０１１４】
この際、無終端環状導波管内に導入されたＴＥ₁₀モードのマイクロ波は、Ｅ分岐で左右に二分配され、自由空間よりも長い管内波長をもって導波路１３内を伝搬する。分配されたマイクロ波同士は干渉しあい、路内波長の１／２毎に６個の“腹”をもつ定在波を生じる。電流が最大になる位置、即ち、隣接する２つの“腹”間の中央に設置されたスロット３３から誘電体窓を透してプラズマ処理室に導入されたマイクロ波は、スロット３３近傍にプラズマを生成する。
【０１１５】
生成したプラズマの電子プラズマ周波数が電源周波数を超える（例えば、電子密度が７×１０¹⁰／ｃｍ³を超える場合、電子プラズマ周波数が電源周波数２．４５ＧＨｚを超える）と、マイクロ波はプラズマ中を伝搬できなくなり（いわゆるカットオフ）、更に電子密度が増加し、
δ＝（２／ωμ₀σ）^1/2
［ω：電源角周波数、μ₀：真空透磁率、σ：プラズマ導電率］
で表される表皮厚が十分薄くなる（例えば、電子密度が２×１０¹²ｃｍ^-3以上になると、表皮厚は４ｍｍ以下になる）と、石英製の誘電体の表面を表面波として伝搬する。
【０１１６】
隣接するスロット３３から導入された表面波同士が干渉し、約３１ｍｍ毎に表面定在波を生じる。プラズマ処理室にしみ出したこの表面定在波によって電子が加速され表面波干渉プラズマが生成する。
【０１１７】
誘電体窓の材質は無水合成石英、直径３００ｍｍ、厚さ１２ｍｍである。無終端環状導波管は、内部導波路断面の寸法が２７ｍｍ×９６ｍｍであって、中心直径が１５２ｍｍ（導波路周長ｌ_gが路内波長λ_gの３倍）である。
【０１１８】
無終端環状導波管の材質は、マイクロ波の伝搬損失を抑えるため、すべてＡｌを用いている。無終端環状導波管のＨ面には、マイクロ波をプラズマ処理室を導入するためのスロット３３が形成されている。スロット３３は、長さ４０ｍｍ、幅４ｍｍの矩形状であり、中心が半径１０３．９ｍｍの円周Ｃ５上にあり放射状に６０°間隔で計６個形成されている。無終端環状導波管には、４Ｅチューナ、方向性結合器、アイソレータ、２．４５ＧＨｚの周波数を持つマイクロ波電源（不図示）が順に接続されている。
【０１１９】
図１８に示したマイクロ波供給器を有するプラズマ処理装置を使用して、Ａｒ流量５００ｓｃｃｍ、圧力１．３３Ｐａ、マイクロ波パワー３．０ｋＷの条件でプラズマを発生させ、得られたプラズマの計測を行った。プラズマ計測は、シングルプローブ法により以下のようにして行った。プローブに印加する電圧を−５０から＋１００Ｖの範囲で変化させ、プローブに流れる電流をＩ−Ｖ測定器により測定し、得られたＩ−Ｖ曲線からラングミュアらの方法により電子密度、電子温度、プラズマ電位を算出した。その結果、電子密度は、１．３３Ｐａの場合、２．１×１０¹²ｃｍ^-3±２．７％（φ３００面内）であり、低圧領域でも電子密度の高い安定したプラズマが形成されていることが確認された。
【０１２０】
（第３の実施形態）
本発明のマイクロ波プラズマ処理装置において、導波路周長／管内波長倍率ｎ_gが３、スロット間表面定在波個数ｎ₁が３、誘電体がＡＩＮ（誘電率ε_w：９．８）の場合のマイクロ波供給器の例を図１９に示す。装置本体の構成は図１６（ａ）等と同じである。
【０１２１】
ここで、スロット３３は、無終端環状導波管内のマイクロ波導波路１３の中央より内側の、半径が略６７．７ｍｍである円周Ｃ２上にスロットの中心が存在するようにオフセットをもって形成されている。
【０１２２】
無終端環状導波管に導入されたＴＥ₁₀モードのマイクロ波は、Ｅ分岐で左右に二分配され、自由空間よりも長い路内波長をもって導波路１３内を伝搬する。分配されたマイクロ波同士は干渉しあい、路内波長の１／２毎に定在波を生じる。電流が最大になる位置、即ち、隣接する２つの定在波間の中央に設置されたスロット３３からＡｌＮ製の誘電体窓４を透してプラズマ処理室に導入されたマイクロ波は、スロット３３近傍にプラズマを生成する。生成したプラズマの電子プラズマ周波数が電源周波数を超える（例えば、電子密度が７×１０¹⁰ｃｍ^-3を超える場合、電子プラズマ周波数が電源周波数２．４５ＧＨｚを超える）と、マイクロ波はプラズマ中を伝搬できなくなり（いわゆるカットオフ）、更に電子密度が増加し、
δ＝（２／ωμ₀σ）^1/2
［ω：電源角周波数、μ₀：真空透磁率、σ：プラズマ導電率］
で表される表皮厚が十分薄くなる（例えば、電子密度が２×１０¹²ｃｍ^-3以上になると、表皮厚は４ｍｍ以下になる）と、誘電体窓４の表面を表面波として伝搬する。
【０１２３】
隣接するスロット３３から導入された表面波同士が干渉し、約２０ｍｍ毎に表面定在波を生じる。プラズマ処理室にしみ出したこの表面定在波によって電子が加速された表面波干渉プラズマが生成する。
【０１２４】
ＡｌＮ製の誘電体窓４は、直径３００ｍｍ、厚さ１２ｍｍである。無終端環状導波管は、内部導波路断面の寸法が２７ｍｍ×９６ｍｍであって、中心直径が１５２ｍｍ（導波路周長ｌ_gが路内波長λ_gの３倍）である。無終端環状導波管の材質は、マイクロ波の伝搬損失を抑えるため、すべてＡｌを用いている。
【０１２５】
無終端環状導波管のＨ面には、マイクロ波をプラズマ処理室へ導入するためのスロット３３が形成されている。スロット３３は、長さ４０ｍｍ、幅４ｍｍの矩形状であり、中心が半径６７．７ｍｍの円周Ｃ２上にあり放射状に６０°間隔で計６個形成されている。無終端環状導波管には、４Ｅチューナ、方向性結合器、アイソレータ、２．４５ＧＨｚの周波数を持つマイクロ波電源が順に接続されている。
【０１２６】
図１９に示したマイクロ波供給器を有するプラズマ処理装置を使用して、Ａｒ流量５００ｓｃｃｍ、圧力１．３３Ｐａ、マイクロ波パワー３．０ｋＷの条件でプラズマを発生させ、得られたプラズマの計測を行った。プラズマ計測は、シングルプローブ法により以下のようにして行った。プローブに印加する電圧を−５０から＋１００Ｖの範囲で変化させ、プローブに流れる電流をＩ−Ｖ測定器により測定し、得られたＩ−Ｖ曲線からラングミュアらの方法により電子密度、電子温度、プラズマ電位を算出した。その結果、電子密度は、１．３３Ｐａの場合、１．９×１０¹²ｃｍ^-3±３．１％（φ３００面内）であり、低圧領域でも電子密度の高い安定したプラズマが形成されていることが確認された。
【０１２７】
（第４の実施形態）
本発明のマイクロ波プラズマ処理装置において、導波路周長／管内波長倍率ｎ_gが４、スロット間表面定在波個数ｎ₁が３及び５、誘電体がＡｌＮ（誘電率ε_w：９．８）の場合のマイクロ波供給器の例を図２０に示す。装置本体の構成は図１６（ａ）の他の装置と同じである。
【０１２８】
ここで、スロット３３は、無終端環状導波管内のマイクロ波導波路１３の中央の内側と外側、即ち、半径が略８２．９ｍｍの円周Ｃ２上と、半径がほぼ１２７．２ｍｍである円周Ｃ５上とに一対のスロット３３の中心がそれぞれ存在するよう直線状に並んで形成されている。
【０１２９】
この際、無終端環状導波管内に導入されたＴＥ₁₀モードのマイクロ波は、Ｅ分岐で左右に二分配され、自由空間よりも長い路内波長をもって導波路を伝搬する。
【０１３０】
分配されたマイクロ波同士は干渉しあい、路内波長の１／２毎に導波路内に定在波を生じる。電流が最大になる位置、即ち、隣接する２つの定在波間の中央に設置されたスロット３３から誘電体窓４を透してプラズマ処理室に導入されたマイクロ波は、スロット３３近傍にプラズマを生成する。生成したプラズマの電子プラズマ周波数が電源周波数を超える（例えば、電子密度が７×１０¹⁰ｃｍ^-3を超える場合、電子プラズマ周波数が電源周波数２．４５ＧＨｚを超える）と、マイクロ波はプラズマ中を伝搬できなくなり（いわゆるカットオフ）、更に電子密度が増加し、
δ＝（２／ωμ₀σ）^1/2
［ω：電源角周波数、μ₀：真空透磁率、σ：プラズマ導電率］
で表される表皮厚が十分薄くなる（例えば、電子密度が２×１０¹²ｃｍ^-3以上になると、表皮厚は４ｍｍ以下になる）と、誘電体窓の表面を表面波として伝搬する。
【０１３１】
隣接するスロット３３から放出された表面波同士が干渉し、約２０ｍｍ毎に表面定在波を生じる。プラズマ処理室にしみ出したこの表面定在波によって電子が加速された表面波干渉プラズマが生成する。
【０１３２】
ＡｌＮ製の誘電体窓は、直径３５０ｍｍ、厚さ１３ｍｍである。無終端環状導波管は、内部導波路断面の寸法が９ｍｍ×９６ｍｍであって、中心径が２０２ｍｍ（導波路周長が路内波長の４倍）である。無終端環状導波管の材質は、マイクロ波の伝搬損失を抑えるため、すべてＡｌを用いている。
【０１３３】
無終端環状導波管のＨ面には、マイクロ波をプラズマ処理室へ導入するためのスロット３３が形成されている。スロット３３は、内側の半径８２．９ｍｍの円周Ｃ２上にあるものが長さ４０ｍｍ、幅４ｍｍの矩形状であり、外側の半径１２７．２ｍｍの円周Ｃ５上にあるものが長さ４６ｍｍ、幅４ｍｍの矩形状であり、それぞれ、放射状に４５°間隔で８組計６個形成されている。無終端環状導波管には、４Ｅチューナ、方向性結合器、アイソレータ、２．４５ＧＨｚの周波数を持つマイクロ波電源ＭＷが順に接続されている。
【０１３４】
図２０に示したマイクロ波供給器を有するプラズマ処理装置を使用して、Ａｒ流量５００ｓｃｃｍ、圧力１０ｍＴｏｒｒ、マイクロ波パワー３．０ｋＷの条件でプラズマを発生させ、得られたプラズマの計測を行った。プラズマ計測は、シングルプローブ法により以下のようにして行った。プローブに印加する電圧を−５０から＋１００Ｖの範囲で変化させ、プローブに流れる電流をＩ−Ｖ測定器により測定し、得られたＩ−Ｖ曲線からラングミュアらの方法により電子密度、電子温度、プラズマ電位を算出した。その結果、電子密度は、１．３３Ｐａの場合、１．９×１０¹²ｃｍ^-3±２．２％（φ３００面内）であり、低圧領域でも電子密度の高い安定したプラズマが形成されていることが確認された。
【０１３５】
本発明に用いられるスロットの偏心量は、前述したとおり使用する処理条件に応じて適宜定められる。特にスロット付平板２３を交換可能に構成すれば、処理条件の変更にも柔軟に対応できる。
【０１３６】
本発明に用いられるスロットの中心が、環状導波路の中心とは異なっている異中心スロットの形状は、前述したとおり各々のスロットの中心が導波路の中心に対して内方及び／又は外方に偏在しているのであれば、１つの矩形状穿孔でも、長さが管内波長の１／４から３／８である穿孔が複数、不連続かつ直線上に配置されたものでも適用可能である。
【０１３７】
本発明に用いられるスロット付平板や環状導波管の材質は、導電体であれば使用可能であるが、マイクロ波の伝搬ロスをできるだけ抑えるため導電率の高いＡｌ，Ｃｕ，Ａｇ／Ｃｕメッキしたステンレススチールなどが最適である。本発明に用いられる環状導波路への導入口の向きは、環状導波路内のマイクロ波伝搬空間に効率よくマイクロ波を導入できるものであれば、Ｈ面Ｔ分岐や接線導入のようにＨ面に平行にマイクロ波を導入できる向き、又はＥ面Ｔ分岐のようにＨ面に垂直に導入できる向きでもよい。又、導入口付近に図１５の符号１０に示したような分配器を設けてもよい。本発明に用いられるマイクロ波進行方向のスロット間隔は、管内波長の１／２もしくは１／４が最適である。
【０１３８】
本発明に用いられるマイクロ波周波数は、０．８ＧＨｚ乃至２０ＧＨｚの範囲から適宜選択することができる。
【０１３９】
本発明に用いられるマイクロ波透過窓の誘電体としては、石英ガラスやＳｉＯ₂系のその他各種ガラス、Ｓｉ₃Ｎ₄，ＮａＣｌ，ＫＣｌ，ＬｉＦ，ＣａＦ₂，ＢａＦ₂，Ａｌ₂Ｏ₃，ＡｌＮ，ＭｇＯなどの無機物が適当であるが、ポリエチレン、ポリエステル、ポリカーボネート、セルロースアセテート、ポリプロピレン、ポリ塩化ビニル、ポリ塩化ビニリデン、ポリスチレン、ポリアミド、ポリイミドなどの有機物のフィルム、シートなども適用可能である。
【０１４０】
本発明のマイクロ波プラズマ処理装置及び処理方法においては、磁界発生手段を用いても良い。本発明において用いられる磁界としては、ミラー磁界なども適用可能であるが、スロット近傍の磁界の磁束密度は基板近傍の磁界の磁束密度よりも大きいマグネトロン磁界が最適である。磁界発生手段としては、コイル以外でも、永久磁石でも使用可能である。コイルを用いる場合には過熱防止のため水冷機構や空冷など他の冷却手段を用いてもよい。
【０１４１】
また、処理のより高品質化のため、紫外光を被処理体表面に照射してもよい。光源としては、被処理体もしくはその上に付着したガスに吸収される光を放射するものなら適用可能で、エキシマレーザ、エキシマランプ、希ガス共鳴線ランプ、低圧水銀ランプなどが適当である。
【０１４２】
本発明のプラズマ処理室内の圧力は１．３３×１０^-2Ｐａ乃至１．３３×１０³Ｐａの範囲、より好ましくは、ＣＶＤの場合１．３３×１０^-1Ｐａ乃至１．３３×１０¹Ｐａ、エッチングの場合６．６５×１０^-2Ｐａから６．６５Ｐａ、アッシングの場合１．３３×１０¹Ｐａから１．３３×１０³Ｐａの範囲から選択することができる。
【０１４３】
本発明によるプラズマ処理方法について図１０（ａ）〜図１０（ｅ）を参照して説明する。
【０１４４】
図１０（ａ）に示すようにシリコン基板のような被処理体１０１の表面にＣＶＤ装置又は表面改質装置により、酸化シリコン、窒化シリコン、窒化酸化シリコン、酸化アルミニウム、酸化タンタル等の無機物や、テトラフルオロエチレン、ポリアリールエーテル等の有機物からなる絶縁膜１０２を形成する。
【０１４５】
図１０（ｂ）に示すようにフォトレジストを塗布して、ベーキングを行いフォトレジスト層１０３を形成する。
【０１４６】
図１０（ｃ）に示すように、露光装置によりホールパターン潜像の形成を行い、これを現像してホール１０４を有するフォトレジストパターン１０３’を形成する。
【０１４７】
図１０（ｄ）に示すように、エッチング装置により、フォトレジストパターン１０３’の下の絶縁膜１０２をエッチングしてホール１０５を形成する。
【０１４８】
図１０（ｅ）に示すように、アッシング装置を用いてフォトレジストパターン１０３’をアッシングして除去する。
【０１４９】
こうして、ホール付絶縁膜を有する構造体が得られる。
【０１５０】
続いて、ホール内に導電体等を堆積させる場合には、前もって、クリーニング装置等によりホール内をクリーニングすることも好ましいものである。
【０１５１】
そして、図１〜図９を参照して説明した本発明によるプラズマ処理装置は、前述した工程に用いられるＣＶＤ装置、表面改質装置、エッチング装置、アッシング装置のうちの少なくともいずれか１つとして利用可能である。
【０１５２】
図１１（ａ）〜図１１（ｃ）は本発明による別のプラズマ処理方法を示している。
【０１５３】
図１１（ａ）に示すようにアルミニウム、銅、モリブデン、クロム、タングステンのような金属或いはこれらの金属のうち少なくとも一つを主成分とする各種合金等からなる導電体のパターン又は多結晶シリコンのパターン（ここではラインアンドスペース）を形成する。
【０１５４】
図１１（ｂ）に示すようにＣＶＤ装置等により絶縁膜１０７を形成する。
【０１５５】
不図示のフォトレジストパターンを形成した後、エッチング装置にて絶縁膜１０７にホール１０８を形成する。
【０１５６】
フォトレジストパターンをアッシング装置等により除去すると図１１（ｃ）に示すような構造体が得られる。
【０１５７】
そして、本発明のプラズマ処理装置は、上述ＣＶＤ装置、エッチング装置、アッシング装置として使用できるが、後述するようにこれらにのみ限定的に適用されるわけではない。
【０１５８】
本発明のマイクロ波プラズマ処理方法による堆積膜の形成は、使用するガスを適宜選択することによりＳｉ₃Ｎ₄，ＳｉＯ₂，Ｔａ₂Ｏ₅，ＴｉＯ₂，ＴｉＮ，Ａｌ₂Ｏ₃，ＡｌＮ，ＭｇＦ₂，フルオロカーボンなどの絶縁膜、ａ−Ｓｉ，ｐｏｌｙ−Ｓｉ，ＳｉＣ，ＧａＡｓなどの半導体膜、Ａｌ，Ｗ，Ｍｏ，Ｔｉ，Ｔａなどの金属膜、アモーファスカーボン、ダイヤモンドライクカーボン、ダイヤモンド等、各種の堆積膜を効率よく形成することが可能である。
【０１５９】
本発明のプラズマ処理方法により処理する被処理体の基体は、半導体であっても、導電性のものであっても、あるいは電気絶縁性のものであってもよい。具体的にはＳｉウエハ、ＳＯＩウエハ等の半導体基体が挙げられる。
【０１６０】
導電性基体としては、Ｆｅ，Ｎｉ，Ｃｒ，Ａｌ，Ｍｏ，Ａｕ，Ｎｂ，Ｔａ，Ｖ，Ｔｉ，Ｐｔ，Ｐｂなどの金属またはこれらの合金、例えば真鍮、ステンレス鋼などが挙げられる。
【０１６１】
絶縁性基体としては、石英ガラスやそれ以外の各種ガラス、Ｓｉ₃Ｎ₄，ＮａＣｌ，ＫＣｌ，ＬｉＦ，ＣａＦ₂，ＢａＦ₂，Ａｌ₂Ｏ₃，ＡｌＮ，ＭｇＯなどの無機物、ポリエチレン、ポリエステル、ポリカーボネート、セルロースアセテート、ポリプロピレン、ポリ塩化ビニル、ポリ塩化ビニリデン、ポリスチレン、ポリアミド、ポリイミドなどの有機物のフィルム、シートなどが挙げられる。
【０１６２】
ＣＶＤ法により基板上に薄膜を形成する場合に用いられるガスとしては、一般に公知のガスが使用できる。
【０１６３】
ａ−Ｓｉ，ｐｏｌｙ−Ｓｉ，ＳｉＣなどのＳｉ系半導体薄膜を形成する場合のＳｉ原子を含有する原料ガスとしては、ＳｉＨ₄，Ｓｉ₂Ｈ₆などの無機シラン類、テトラエチルシラン（ＴＥＳ），テトラメチルシラン（ＴＭＳ），ジメチルシラン（ＤＭＳ），ジメチルジフルオロシラン（ＤＭＤＦＳ），ジメチルジクロルシラン（ＤＭＤＣＳ）などの有機シラン類、ＳｉＦ₄，Ｓｉ₂Ｆ₆，Ｓｉ₃Ｆ₈，ＳｉＨＦ₃，ＳｉＨ₂Ｆ₂，ＳｉＣｌ₄，Ｓｉ₂Ｃｌ₆，ＳｉＨＣｌ₃，ＳｉＨ₂Ｃｌ₂，ＳｉＨ₃Ｃｌ，ＳｉＣｌ₂Ｆ₂などのハロシラン類等、常温常圧でガス状態であるものまたは容易にガス化し得るものが挙げられる。また、この場合のＳｉ原料ガスと混合して導入してもよい添加ガスまたはキャリアガスとしては、Ｈ₂，Ｈｅ，Ｎｅ，Ａｒ，Ｋｒ，Ｘｅ，Ｒｎが挙げられる。
【０１６４】
Ｓｉ₃Ｎ₄，ＳｉＯ₂などのＳｉ化合物系薄膜を形成する場合のＳｉ原子を含有する原料としては、ＳｉＨ₄，Ｓｉ₂Ｈ₆などの無機シラン類、テトラエトキシシラン（ＴＥＯＳ）、テトラメトキシシラン（ＴＭＯＳ）、オクタメチルシクロテトラシラン（ＯＭＣＴＳ）、ジメチルジフルオロシラン（ＤＭＤＦＳ）、ジメチルジクロルシラン（ＤＭＤＣＳ）などの有機シラン類、ＳｉＦ₄，Ｓｉ₂Ｆ₆，Ｓｉ₃Ｆ₈，ＳｉＨＦ₃，ＳｉＨ₂Ｆ₂，ＳｉＣｌ₄，Ｓｉ₂Ｃｌ₆，ＳｉＨＣｌ₃，ＳｉＨ₂Ｃｌ₂，ＳｉＨ₃Ｃｌ，ＳｉＣｌ₂Ｆ₂などのハロゲン化シラン類等、常温常圧でガス状態であるものまたは容易にガス化し得るものが挙げられる。また、この場合の同時に導入する窒素原料ガスまたは酸素原料ガスとしては、Ｎ₂，ＮＨ₃，Ｎ₂Ｈ₄、ヘキサメチルジシラザン（ＨＭＤＳ）、Ｏ₂，Ｏ₃，Ｈ₂Ｏ，ＮＯ，Ｎ₂Ｏ，ＮＯ₂などが挙げられる。
【０１６５】
Ａｌ，Ｗ，Ｍｏ，Ｔｉ，Ｔａなどの金属薄膜を形成する場合の金属原子を含有する原料としては、トリメチルアルミニウム（ＴＭＡｌ）、トリエチルアルミニウム（ＴＥＡｌ）、トリイソブチルアルミニウム（ＴＩＢＡｌ）、ジメチルアルミニウムハイドライド（ＤＭＡｌＨ）、タングステンカルボニル（Ｗ（ＣＯ）₆）、モリブデンカルボニル（Ｍｏ（ＣＯ）₆）、トリメチルガリウム（ＴＭＧａ）、トリエチルガリウム（ＴＥＧａ）などの有機金属、ＡｌＣｌ₃，ＷＦ₆，ＴｉＣｌ₃，ＴａＣｌ₅などのハロゲン化金属等が挙げられる。また、この場合のＳｉ原料ガスと混合して導入してもよい添加ガスまたはキャリアガスとしては、Ｈ₂，Ｈｅ，Ｎｅ，Ａｒ，Ｋｒ，Ｘｅ，Ｒｎが挙げられる。
【０１６６】
Ａｌ₂Ｏ₃，ＡｌＮ，Ｔａ₂Ｏ₅，ＴｉＯ，ＴｉＮ，ＷＯ₃などの金属化合物薄膜を形成する場合の金属原子を含有する原料としては、トリメチルアルミニウム（ＴＭＡｌ）、トリエチルアルミニウム（ＴＥＡｌ）、トリイソブチルアルミニウム（ＴＩＢＡｌ）、ジメチルアルミニウムハイドライド（ＤＭＡｌＨ）、タングステンカルボニル（Ｗ（ＣＯ）₆）、モリブデンカルボニル（Ｍｏ（ＣＯ）₆）、トリメチルガリウム（ＴＭＧａ）、トリエチルガリウム（ＴＥＧａ）などの有機金属、ＡｌＣｌ₃，ＷＦ₆，ＴｉＣｌ₃，ＴａＣｌ₅などのハロゲン化金属等が挙げられる。また、この場合の同時に導入する酸素原料ガスまたは窒素原料ガスとしては、Ｏ₂，Ｏ₃，Ｈ₂Ｏ，ＮＯ，Ｎ₂Ｏ，ＮＯ₂，Ｎ₂，ＮＨ₃，Ｎ₂Ｈ₄、ヘキサメチルジシラザン（ＨＭＤＳ）などが挙げられる。アモーファスカーボン、ダイヤモンドライクカーボン、ダイヤモンド等のカーボン膜を形成する場合には、ＣＨ₄，Ｃ₂Ｈ₆等の炭素含有ガスを、フルオロカーボン膜を形成する場合には、ＣＦ₄やＣ₂Ｆ₆等のフッ素、炭素含有ガスを用いるとよい。
【０１６７】
基体表面をエッチングする場合のエッチング用ガスとしては、Ｆ₂，ＣＦ₄，ＣＨ₂Ｆ₂，Ｃ₂Ｆ₆，Ｃ₄Ｆ₈，ＣＦ₂Ｃｌ₂，ＳＦ₆，ＮＦ₃，Ｃｌ₂，ＣＣｌ₄，ＣＨ₂Ｃｌ₂，Ｃ₂Ｃｌ₆などが挙げられる。
【０１６８】
フォトレジストなど基体表面上の有機成分をアッシング除去する場合アッシング用ガスとしては、Ｏ₂，Ｏ₃，Ｈ₂Ｏ，Ｎ₂，ＮＯ，Ｎ₂Ｏ，ＮＯ₂などが挙げられる。
【０１６９】
また本発明のマイクロ波プラズマ処理装置及び処理方法を表面改質にも適用する場合、使用するガスを適宜選択することにより、例えば基体もしくは表面層としてＳｉ，Ａｌ，Ｔｉ，Ｚｎ，Ｔａなどを使用してこれら基体もしくは表面層の酸化処理あるいは窒化処理さらにはＢ，Ａｓ，Ｐなどのドーピング処理等が可能である。更に本発明はクリーニング方法にも適用できる。その場合酸化物あるいは有機物や重金属などを除去するクリーニングに使用することもできる。
【０１７０】
基体を酸化表面処理する場合の酸化性ガスとしては、Ｏ₂，Ｏ₃，Ｈ₂Ｏ，ＮＯ，Ｎ₂Ｏ，ＮＯ₂などが挙げられる。また、基体を窒化表面処理する場合の窒化性ガスとしては、Ｎ₂，ＮＨ₃，Ｎ₂Ｈ₄、ヘキサメチルジシラザン（ＨＭＤＳ）などが挙げられる。
【０１７１】
基体表面の有機物をクリーニングする場合、またはフォトレジストなど基体表面上の有機成分をアッシング除去する場合のクリーニング／アッシング用ガスとしては、Ｏ₂，Ｏ₃，Ｈ₂Ｏ，Ｈ₂，ＮＯ，Ｎ₂Ｏ，ＮＯ₂などが挙げられる。また、基体表面の無機物をクリーニングする場合のクリーニング用ガスとしては、Ｆ₂，ＣＦ₄，ＣＨ₂Ｆ₂，Ｃ₂Ｆ₆，Ｃ₄Ｆ₈，ＣＦ₂Ｃｌ₂，ＳＦ₆，ＮＦ₃などが挙げられる。
【０１７２】
【実施例】
（実施例１）
図１６（ａ）〜１６（ｃ）に示したマイクロ波プラズマ処理装置を使用し、フォトレジストのアッシングを行った。
被処理体としては、層間ＳｉＯ₂膜をエッチングし、ビアホールを形成した直後のシリコン（Ｓｉ）基板（φ８インチ）を使用した。
【０１７３】
先ず、Ｓｉ基板を支持体２上に設置し、温度調節手段１１４としてのヒータを用いてＳｉ基板を２５０℃に加熱した後、排気系を介してプラズマ処理室を真空排気し、１．３３×１０^-3Ｐａまで減圧させた。プラズマ処理ガス供給口７を介して酸素ガスを５００ｓｃｃｍの流量でプラズマ処理室に導入した。
【０１７４】
次いで、プラズマ処理室と排気ポンプ１８との間に設けられたコンダクタンスバルブ２８を調整し、処理室を４０Ｐａに保持した。プラズマ処理室に、２．４５ＧＨｚのマイクロ波電源ＭＷより１．５ｋＷの電力を無終端環状導波管を介して供給した。
【０１７５】
かくして、プラズマ処理室にプラズマを発生させた。この際、プラズマ処理ガス供給口７を介して導入された酸素ガスはプラズマ処理室で励起、分解、反応して酸素ラジカルとなり、Ｓｉ基板の方向に輸送され、Ｓｉ基板上のフォトレジストを酸化し、排気系側に排出除去された。アッシング後、アッシング速度と基板表面電荷密度などについて評価した。
【０１７６】
得られたアッシング速度及び均一性は、５．６μｍ／ｍｉｎ±４．５％と極めて良好で、表面電荷密度も、−１．３×１０¹¹ｃｍ^-2と充分低い値を示した。
【０１７７】
（実施例２）
図１７に示したマイクロ波供給器を有するプラズマ処理装置を使用し、フォトレジストのアッシングを行った。
被処理体Ｗとしては、層間ＳｉＯ₂膜をエッチングし、ビアホールを形成した直後のシリコン（Ｓｉ）基板（φ８インチ）を使用した。
【０１７８】
先ず、Ｓｉ基板を支持体２上に設置した後、排気系を介してプラズマ処理室を真空排気し、１．３３×１０^-3Ｐａまで減圧させた。プラズマ処理ガス供給口を介して酸素ガスを１ｓｌｍの流量でプラズマ処理室に導入した。
【０１７９】
次いで、プラズマ処理室と排気ポンプ１８との間に設けられたコンダクタンスバルブ２８を調整し、処理室を８０Ｐａに保持した。プラズマ処理室に、２．４５ＧＨｚのマイクロ波電源より１．５ｋＷのＴＥ₁₀モードのマイクロ波電力を無終端環状導波管を介して供給した。
【０１８０】
かくして、プラズマ処理室内にプラズマを発生させた。この際、プラズマ処理ガス供給口７を介して導入された酸素ガスはプラズマ処理室で励起、分解、反応して酸素ラジカルとなり、Ｓｉ基板の方向に輸送され、基板上のフォトレジストを酸化し、気化・除去された。アッシング後、アッシング速度と基板表面電荷密度などについて評価した。
【０１８１】
得られたアッシング速度及び均一性は、５．４μｍ／ｍｉｎ±３．４％と極めて大きく、表面電荷密度も−１．４×１０¹¹ｃｍ^-2と充分低い値を示した。
【０１８２】
（実施例３）
図１６（ａ）〜１６（ｃ）に示したマイクロ波プラズマ処理装置を使用し、半導体素子保護用の窒化シリコン膜の形成を行った。
被処理体としては、Ａｌ配線パターン（ラインアンドスペース０．５μｍ）が形成された層間ＳｉＯ₂膜付きＰ型単結晶シリコン基板（面方位〈１００〉、抵抗率１０Ωｃｍ）を使用した。
【０１８３】
先ず、シリコン基板を支持台２上に設置した後、排気系を介してプラズマ処理室を真空排気し、１．３３×１０^-5Ｐａの値まで減圧させた。
【０１８４】
次いで、温度調整手段としてのヒータ１１４に通電し、シリコン基板を３００℃に加熱し、該基板をこの温度に保持した。プラズマ処理ガス供給口を介して窒素ガスを６００ｓｃｃｍの流量で、また、モノシランガスを２００ｓｃｃｍの流量で処理室に導入した。
【０１８５】
次いで、プラズマ処理室と排気ポンプ１８との間に設けられたコンダクタンスバルブ１８を調整し、処理室を２．６７Ｐａに保持した。
【０１８６】
次いで、２．４５ＧＨｚのマイクロ波電源ＭＷより３．０ｋＷの電力を無終端環状導波管を介して供給した。
【０１８７】
かくして、プラズマ処理室にプラズマを発生させた。この際、プラズマ処理ガス供給口７を介して導入された酸素ガスはプラズマ処理室で励起、分解されて活性種となり、シリコン基板の方向に輸送され、モノシランガスと反応し、窒化シリコン膜がシリコン基板上に１．０μｍの厚さで形成した。
【０１８８】
成膜後、成膜速度、応力などの膜質について評価した。応力は成膜前後の基板の反り量の変化をレーザ干渉計Ｚｙｇｏ（商品名）で測定し求めた。
得られた窒化シリコン膜の成膜速度及び均一性は、５３０ｎｍ／ｍｉｎ±３．５％と極めて大きく、膜質も応力１．２×１０⁹ｄｙｎｅ／ｃｍ²（圧縮）、リーク電流１．２×１０^-10Ａ／ｃｍ²、絶縁耐圧９ＭＶ／ｃｍの極めて良質な膜であることが確認された。
【０１８９】
（実施例４）
図１９に示したマイクロ波供給器を有するプラズマ処理装置を使用し、プラスチックレンズ反射防止用酸化シリコン膜及び窒化シリコン膜の形成を行った。
被処理体としては、直径５０ｍｍプラスチック凸レンズを使用した。レンズを支持台２上に設置した後、排気系を介してプラズマ処理室を真空排気し、１．３３×１０^-5Ｐａの値まで減圧させた。プラズマ処理ガス供給口７を介して窒素ガスを１６０ｓｃｃｍの流量で、また、モノシランガスを１００ｓｃｃｍの流量で処理室に導入した。
【０１９０】
次いで、プラズマ処理室と排気ポンプ１８との間に設けられたコンダクタンスバルブ２８を調整し、処理室を９．３３Ｐａに保持した。
【０１９１】
次いで、２．４５ＧＨｚのマイクロ波電源ＭＷより３．０ｋＷの電力を無終端環状導波管を介してプラズマ処理室に供給した。
【０１９２】
かくして、プラズマ処理室にプラズマを発生させた。この際、プラズマ処理ガス供給口を介して導入された窒素ガスは、プラズマ処理室で励起、分解されて窒素原子などの活性種となり、レンズの方向に輸送され、モノシランガスと反応し、窒化シリコン膜がレンズ上に２１ｎｍの厚さで形成された。
【０１９３】
次いで、プラズマ処理ガス供給口を介して酸素ガスを２００ｓｃｃｍの流量で、また、モノシランガスを１００ｓｃｃｍの流量で処理室に導入した。
【０１９４】
次いで、プラズマ処理室と排気ポンプ１８との間に設けられたコンダクタンスバルブ２８を調整し、処理室を０．１３Ｐａに保持した。ついで、２．４５ＧＨｚのマイクロ波電源ＭＷより２．０ｋＷの電力を無終端環状導波管を介してプラズマ処理室に供給した。
【０１９５】
かくして、プラズマ処理室にプラズマを発生させた。この際、プラズマ処理ガス供給口を介して導入された酸素ガスは、プラズマ処理室で励起、分解されて酸素原子などの活性種となり、レンズの方向に輸送され、モノシランガスと反応し、酸化シリコン膜がレンズ上に８６ｎｍの厚さで形成された。成膜後、成膜速度、反射特性について評価した。
【０１９６】
得られた窒化シリコン膜及び酸化シリコン膜の成膜速度及び均一性はそれぞれ３３０ｎｍ／ｍｉｎ±２．４％、３５０ｎｍ／ｍｉｎ±２．６％と良好であり、膜質も５００ｎｍ付近の反射率が０．２％と極めて良好な光学特性であることが確認された。
【０１９７】
（実施例５）
図２０に示したマイクロ波供給器を有するプラズマ処理装置を使用し、半導体素子層間絶縁用酸化シリコン膜の形成を行った。
被処理体としては、最上部にＡｌパターン（ラインアンドスペース０．５μｍ）が形成されたＰ型単結晶シリコン基板（面方位〈１００〉、抵抗率１０Ωｃｍ）を使用した。
【０１９８】
先ず、シリコン基板を支持台２上に設置した後、排気系を介してプラズマ処理室を真空排気し、１．３３×１０^-5Ｐａの値まで減圧させた。
【０１９９】
続いて、ヒータに通電し、シリコン基板を３００℃に加熱し、該基板をこの温度に保持した。プラズマ処理ガス供給口７を介して酸素ガスを５００ｓｃｃｍの流量で、また、モノシランガスを２００ｓｃｃｍの流量で処理室に導入した。
【０２００】
次いで、プラズマ処理室と排気ポンプ１８との間に設けられたコンダクタンスバルブ２８を調整し、プラズマ処理室を４．０Ｐａに保持した。
【０２０１】
次いで、１３．５６ＭＨｚの高周波印加手段２２を介して３００Ｗの電力を支持体２に印加するとともに、２．４５ＧＨｚのマイクロ波電源より２．０ｋＷの電力を無終端環状導波管を介してプラズマ処理室に供給した。
【０２０２】
かくして、プラズマ処理室にプラズマを発生させた。プラズマ処理ガス供給口７を介して導入された酸素ガスはプラズマ処理室で励起、分解されて活性種となり、シリコン基板の方向に輸送され、モノシランガスと反応し、酸化シリコン膜がシリコン基板上に０．８μｍの厚さで形成された。この時、イオン種はＲＦバイアスにより加速されて基板に入射しパターン上の膜を削り平坦性を向上させる。処理後、成膜速度、均一性、絶縁耐圧、及び段差被覆性について評価した。段差被覆性は、Ａｌ配線パターン上に成膜した酸化シリコン膜の断面を走査型電子顕微鏡（ＳＥＭ）で観測し、ボイドを観測することにより評価した。
【０２０３】
得られた酸化シリコン膜の成膜速度及び均一性は２５０ｎｍ／ｍｉｎ±２．７％と良好で、膜質も絶縁耐圧８．５ＭＶ／ｃｍ、ボイドフリーであって良質な膜であることが確認された。
【０２０４】
（実施例６）
図２０に示したマイクロ波供給器を有するプラズマ処理装置を使用し、半導体素子の層間ＳｉＯ₂膜のエッチングを行った。
被処理体としては、Ａｌパターン（ラインアンドスペース０．１８μｍ）上に１μｍ犀の層間ＳｉＯ₂膜が形成されたＰ型単結晶シリコン基板（面方位〈１００〉、抵抗率１０Ωｃｍ）を使用した。
【０２０５】
先ず、シリコン基板を支持台２上に設置した後、排気系を介して処理室を真空排気し、１．３３×１０^-5Ｐａの値まで減圧した。プラズマ処理ガス供給口７を介してＣ₄Ｆ₈を１００ｓｃｃｍの流量でプラズマ処理室に導入した。
【０２０６】
次いで、プラズマ処理室と排気ポンプ１８との間に設けられたコンダクタンスバルブ２８を調整し、プラズマ処理室を１．３３Ｐａの圧力に保持した。
【０２０７】
次いで、１３．５６ＭＨｚの高周波印加手段２２を介して３００Ｗの電力を支持体２に印加するとともに、２．４５ＧＨｚのマイクロ波電源より２．０ｋＷの電力を無終端環状導波管を介してプラズマ処理室に供給した。
【０２０８】
かくして、プラズマ処理室にプラズマを発生させた。プラズマ処理ガス供給口７を介して導入されたＣ₄Ｆ₈ガスはプラズマ処理室で励起、分解されて活性種となり、シリコン基板の方向に輸送され、自己バイアスによって加速されたイオンによって層間ＳｉＯ₂膜がエッチングされた。
【０２０９】
温度調整手段としてのクーラ１１４により基板温度は８０℃までしか上昇しなかった。エッチング後、エッチング速度、選択比、及びエッチング形状について評価した。エッチング形状は、エッチングされた酸化シリコン膜の断面を走査型電子顕微鏡（ＳＥＭ）で観測し、評価した。
【０２１０】
エッチング速度及び均一性と対ＰＲ選択比は５６０ｎｍ／ｍｉｎ±３．２％、１５と良好で、エッチング形状もほぼ垂直であり、マイクロローディング効果も少ないことが確認された。
【０２１１】
（実施例７）
図２０に示したマイクロ波プラズマ処理装置を使用し、低誘電率絶縁体としての半導体素子層間絶縁用ポリアリールエーテル（ＰＡＥ）膜のエッチングを行った。
被処理体Ｗとしては、０．６μｍ厚のＰＡＥ膜上にハードマスクとして０．１８μｍのＳｉＯ₂膜パターンが０．３μｍ厚に形成されたＰ型単結晶シリコン基板（面方位〈１００〉、抵抗率１０Ωｃｍ）を使用した。
【０２１２】
先ず、シリコン基板を支持台２上に設置し、温度調整手段としてのクーラ１１４により基板温度を−１０℃に冷却した後、排気系を介してプラズマ処理室を真空排気し、１．３３×１０^-5Ｐａの値まで減圧した。処理ガス供給口７を介してＮ₂を２００ｓｃｃｍの流量でプラズマ処理室に導入した。
【０２１３】
次いで、プラズマ処理室と排気ポンプ１８との間に設けられたコンダクタンスバルブ２８を調整し、プラズマ処理室を１．３３Ｐａの圧力に保持した。
【０２１４】
次いで、１ＭＨｚの高周波印加手段２２を介して３００Ｗの電力を支持体２に印加するとともに、２．４５ＧＨｚのマイクロ波電源より２．０ｋＷの電力を無終端環状導波管を介してプラズマ処理室に供給した。
【０２１５】
かくして、プラズマ処理室にプラズマを発生させた。処理ガス供給口７を介して導入されたＮ₂ガスはプラズマ処理室で励起、分解されて活性種となり、シリコン基板の方向に輸送され、自己バイアスによって加速されたイオンによってＰＡＥ膜がエッチングされた。
【０２１６】
エッチング後、エッチング速度、選択比、及びエッチング形状について評価した。エッチング形状は、エッチングされた酸化シリコン膜の断面を走査型電子顕微鏡（ＳＥＭ）で観測し、評価した。
【０２１７】
エッチング速度及び均一性と対ＳｉＯ₂選択比は６６０ｎｍ／ｍｉｎ±３．７％、１０と良好で、エッチング形状もほぼ垂直で、マイクロローディング効果も少ないことが確認された。
【０２１８】
【発明の効果】
本発明によれば、低圧・低パワーで処理を行う場合でも、高品質な処理を高速・均一かつ安定に行うことが可能になるように、高密度低電子温度プラズマを安定して発生できるプラズマ処理装置及びプラズマ処理方法が実現する。
【０２１９】
本発明によれば、マイクロ波の放射特性をより精密に制御できるので、被処理体の半径方向及び周方向或いはこれらに等価な方向における処理の制御性を高めることができる。
【図面の簡単な説明】
【図１】本発明によるプラズマ処理装置を示す断面図である。
【図２】本発明に用いられるスロット付平板の一例を示す平面図である。
【図３】本発明による別のプラズマ処理装置を示す断面図である。
【図４】本発明に用いられるスロット付平板の他の例を示す平面図である。
【図５】本発明による環状導波管を用いたマイクロ波プラズマ処理装置の模式的断面図である。
【図６】スロット付平板の上面図である。
【図７】本発明による接線導入型の環状導波管を用いたマイクロ波プラズマ処理装置の模式断面図である。
【図８】本発明による他のマイクロ波プラズマ処理装置の模式断面図である。
【図９】本発明による他のマイクロ波プラズマ処理装置の模式断面図である。
【図１０】プラズマ処理方法の一例を示す図である。
【図１１】プラズマ処理方法の別の例を示す図である。
【図１２】プラズマ処理装置の構成を示す図である。
【図１３】マイクロ波供給器の断面図である。
【図１４】導波路の断面図である。
【図１５】マイクロ波の放射の様子を示す図である。
【図１６】本発明の他の実施形態によるプラズマ処理装置、本発明に用いられるマイクロ波供給器、及び本発明に用いられるマイクロ波供給器におけるマイクロ波伝搬の様子を示す模式図である。
【図１７】スロットの配置を示す模式図である。
【図１８】本発明に用いられるマイクロ波供給器の模式図である。
【図１９】本発明に用いられるマイクロ波供給器の模式図である。
【図２０】本発明に用いられるマイクロ波供給器の模式図である。
【符号の説明】
１ 真空容器
２ 被処理体保持手段
３ マイクロ波供給器
４ 誘電体窓
５ 導波管
６ マイクロ波電源
７ ガス供給路
８ 排気路
９ プラズマ発生空間
３３ スロット[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a plasma processing apparatus for performing plasma processing on an object to be processed using microwaves, and in particular, a plasma processing apparatus including a microwave supply device having an annular waveguide, a plasma processing method, and a structure manufacturing method. About.
[0002]
[Prior art]
Known plasma processing equipment that uses microwaves as an excitation source for plasma excitation includes plasma polymerization equipment, CVD equipment, surface modification equipment, etching equipment, ashing equipment, cleaning equipment, etc. used in the manufacture of structures. Yes.
[0003]
For example, CVD using such a so-called microwave plasma processing apparatus is performed as follows. That is, a gas is introduced into a plasma generation chamber and / or a film formation chamber of a microwave plasma CVD apparatus, and at the same time, microwave energy is input to generate a plasma in the plasma generation chamber to excite, dissociate, and ionize the gas. Thus, ions and radicals are generated to form a deposited film on the object to be processed disposed in the plasma generation chamber or the film formation chamber separated from the plasma generation chamber. Then, surface modification such as plasma polymerization of organic matter, oxidation, nitridation, and fluorination can be performed in the same manner.
[0004]
Moreover, the etching process of the to-be-processed object which uses what is called a microwave plasma etching apparatus is performed as follows, for example. That is, an etchant gas is introduced into the processing chamber of the apparatus, and at the same time, microwave energy is supplied to generate plasma in the processing chamber. The surface of the object to be processed disposed in the room is etched.
[0005]
Moreover, the ashing process of the to-be-processed object which uses what is called a microwave plasma ashing apparatus is performed as follows, for example. That is, an ashing gas is introduced into the processing chamber of the apparatus, and at the same time, microwave energy is input to generate plasma in the processing chamber. By ashing, the surface of the object to be processed, that is, the photoresist, disposed in the processing chamber. In the same manner as ashing, it is possible to perform cleaning to remove unnecessary substances attached to the surface to be processed.
[0006]
In the microwave plasma processing apparatus, since a microwave is used as a gas excitation source, electrons can be accelerated by an electric field having a high frequency, and gas molecules can be efficiently ionized and excited. Therefore, the microwave plasma processing apparatus has the advantages that gas ionization efficiency, excitation efficiency and dissociation efficiency are high, high-density plasma can be formed relatively easily, and high-quality processing can be performed at a low temperature and at high speed. In addition, since the microwave has a property of transmitting a dielectric such as quartz glass, the plasma processing apparatus can be configured as an electrodeless discharge type, and therefore there is an advantage that highly clean plasma processing can be performed.
[0007]
In order to further increase the speed of such a microwave plasma processing apparatus, a plasma processing apparatus using electron cyclotron resonance (ECR) has been put into practical use. In the ECR, when the magnetic flux density is 87.5 mT, the electron cyclotron frequency at which the electrons rotate around the magnetic field lines matches the general microwave frequency of 2.45 GHz, and the electrons absorb the microwaves resonantly. This is a phenomenon in which high-density plasma is generated by acceleration. Another type of plasma processing apparatus for generating high-density plasma has also been proposed.
[0008]
For example, in US Pat. No. 5,034,086, a plasma processing apparatus using a radial line slot antenna (RLSA) is disclosed.
[0009]
Alternatively, Japanese Patent Laid-Open No. 5-290995, US Pat. No. 5,359,177, and EP 0564359 disclose a plasma processing apparatus using a terminating annular waveguide.
[0010]
Apart from these, as an example of a microwave plasma processing apparatus, in recent years, an apparatus using an endless annular waveguide in which a plurality of slots are formed on the inner surface has been proposed as a uniform and efficient microwave introduction apparatus. (Japanese Patent Laid-Open No. 5-34592, US Pat. No. 5,538,699).
[0011]
However, using a conventional microwave plasma processing apparatus having an endless annular waveguide having a slot on the inner surface, for example, in a high pressure region of 100 mTorr (about 13.3 Pa) or more as in the case of ashing processing In the case of performing the above, since the diffusion of the plasma is suppressed, the plasma may be localized in the periphery and the processing speed of the central portion of the substrate may be lowered. Further, the volume of the plasma generation space becomes very large.
[0012]
On the other hand, Japanese Patent Application Laid-Open No. 7-90591 discloses a plasma processing apparatus using a disk-shaped microwave introduction apparatus. In this apparatus, a gas is introduced into a waveguide, and the gas is discharged from a slot provided in the waveguide toward a plasma generation chamber.
[0013]
In contrast to these conventional apparatuses, the configuration of the plasma processing apparatus previously proposed by the present inventor is as shown in FIG.
[0014]
1 is a container that can be evacuated, 2 is a holding means for the object to be processed, 3 is a microwave feeder comprising an annular waveguide having an annular waveguide inside, 4 is a dielectric window, and 7 is a gas supply port 7a. A gas supply pipe having In the apparatus assembled from these components, the microwave is introduced from the microwave introduction port 15 of the microwave supply device 3 and the microwave is supplied from the slot 36 into the container 1 through the dielectric window 4.
[0015]
FIGS. 13 to 15 are schematic diagrams for explaining the propagation of microwaves and the radiation of microwaves from the slots in the annular waveguide of the microwave feeder.
[0016]
FIG. 13 shows a state where the annular waveguide is viewed from above, with the slots omitted. 14 shows a cross section taken along line B-B ′ of FIG. 13, and FIG. 15 shows a cross section taken along line C-C ′.
[0017]
The vicinity of the microwave inlet 15 is an E-plane T-branch equivalent circuit, and the microwave introduced from the microwave inlet 15 is clockwise d.₂And counterclockwise d₁The course is changed so that it is distributed. Each slot 3b has a microwave traveling direction d.₁, D₂The microwaves travel while emitting microwaves from the slots.
[0018]
Since the annular waveguide is endless, the direction d₁, D₂Microwaves propagating in the (z-axis direction) interfere with each other. C1 indicates a ring (ring) formed by connecting the centers of the waveguides. When this length, that is, the circumference, is an integral multiple of the guide wavelength (intra-path wavelength), a standing wave of a predetermined mode is generated. It becomes easy to generate.
[0019]
FIG. 14 shows a cross section perpendicular to the microwave traveling direction (z-axis direction), and the upper and lower surfaces 3c of the waveguide are H surfaces perpendicular to the direction of the electric field EF. The surface 3d is an E surface parallel to the direction of the electric field EF. C0 is the center in the longitudinal direction of the slot 3b, that is, the direction perpendicular to the microwave traveling / propagating direction (x-axis direction).
[0020]
Thus, the cross section perpendicular to the microwave traveling direction of the waveguide is a rectangular cross section with the x axis and the y axis as long sides and short sides.
[0021]
The microwave MW introduced into the annular waveguide 3a is divided into left and right by the distribution block 10 having an E-plane T branch, and propagates with an in-tube wavelength longer than the free space. The distributed microwaves interfere with each other at the facing portion, and a standing wave is generated every ½ of the guide wavelength. The leakage wave EW radiated through the dielectric window 4 from the slot 3b installed at a position where the electric field across the slot is maximized generates a plasma P1 in the vicinity of the slot 3b. The electron frequency of the generated plasma P1 exceeds the frequency of the microwave power supply (for example, when the power supply frequency is 2.45 GHz, the electron density is 7 × 10^Tencm^-3The microwave cannot propagate in the plasma, so-called cutoff occurs, and propagates as a surface wave SW at the interface between the dielectric window 4 and the plasma. The surface waves SW introduced from adjacent slots interfere with each other, and the wavelength of the surface wave SW (λ · ε_r ^-1/2[Λ: free-space microwave wavelength, ε_r: Relative permittivity]) every half of the dielectric constant]). Surface wave interference plasma (SIP: Surface-wave Interfered Plasma) P <b> 2 is generated by the anti-electric field generated by the surface wave interference that oozes out to the plasma generation space side 1. When the processing gas is introduced into the plasma processing chamber at this time, the processing gas is excited, dissociated, and ionized by the generated high-density plasma, and the surface of the substrate to be processed can be processed.
[0022]
By using such a microwave plasma processing apparatus, the electron density is 10% with a uniformity of within ± 3% in a space having a diameter of 300 mm or more at a pressure of about 1.33 Pa, a microwave power of 1 kW or more.¹²/ Cm^ThreeAs described above, high density low potential plasma having an electron temperature of 3 eV or less and a plasma potential of 20 V or less can be generated.
[0023]
Therefore, the gas can be sufficiently reacted and supplied to the surface to be processed in an active state. Moreover, when the pressure is 2.7 Pa and the microwave power is 2 kW, the current due to the microwave cannot be detected at a position 8 to 10 mm away from the inner surface of the dielectric window. This means that a very thin plasma layer can be formed in the vicinity of the dielectric window in the high pressure region where plasma diffusion is suppressed. Therefore, substrate surface damage due to incident ions is reduced, and high quality and high speed processing is possible even at low temperatures.
[0024]
By the way, the circumferential length of the annular waveguide must be selected from two times, three times, four times, etc. of the guide wavelength according to the area to be processed of the object to be processed. In the case where the air in the passage is atmospheric pressure, the perimeters that can be selected are about 318 mm, about 477 mm, about 636 mm, etc., considering that the wavelength in this tube is about 159 mm. When this is converted into the diameter of the ring, it becomes about 101 mm, about 151 mm, and about 202 mm.
[0025]
On the other hand, when a general 8-inch wafer and 12-inch wafer are used as the object to be processed, the diameters are about 200 mm and about 300 mm, respectively. Choosing the optimal combination by combining the two is still not sufficient in terms of plasma uniformity and processing uniformity. For example, the plasma density decreases near the center of the workpiece and the processing speed is reduced. May occur, or the plasma density may decrease near the outer periphery of the object to be processed, resulting in a decrease in processing speed.
[0026]
[Problems to be solved by the invention]
An object of the present invention is to provide a microwave feeder capable of more precisely controlling the microwave radiation characteristics in the radial direction of the ring or an equivalent direction thereof.
[0027]
Another object of the present invention is to provide a plasma processing apparatus and a plasma processing method that can further improve the uniformity of processing in the radial direction of an object to be processed.
[0028]
Still another object of the present invention is to provide a microwave feeder capable of improving the microwave radiation uniformity in the radial direction and circumferential direction of the ring or in an equivalent direction.
[0029]
Another object of the present invention is to provide a plasma processing apparatus and a plasma processing method capable of improving both the uniformity of processing in the radial direction and circumferential direction of the object to be processed, or directions equivalent thereto.
[0030]
[Means for Solving the Problems]
The plasma processing apparatus according to the present invention includes a plasma including a container, a gas supply port for supplying a processing gas into the container, and a microwave supplier for supplying a microwave into the container through a dielectric window. In the processing apparatus, the microwave supply device includes an annular waveguide having a plurality of slots provided at predetermined intervals on a surface in contact with the dielectric window, and n₁The number of antinodes of the surface standing wave generated between the slots, λ_FiveIs the wavelength of the surface wave, n_gThe wavelength λ_gCircumference of the annular waveguide with respect to 1_gThe radius r_eStands for,
r_e= N₁λ_Five/ {2 tan (π / (2n_g))} {1 + cos (π / n_g)}
The center of the slot exists on the circumference of
[0031]
In one aspect of the plasma processing apparatus of the present invention, n_gThe value of is in the range of 2-5.
[0032]
In one aspect of the plasma processing apparatus of the present invention, the angular interval of the slots is π / n._gIt is.
[0033]
In one aspect of the plasma processing apparatus of the present invention, the number n of antinodes of surface standing waves generated between the slots.₁Is either 3, 5, or 7.
[0034]
In one aspect of the plasma processing apparatus of the present invention, the dielectric window is mainly composed of aluminum nitride.
[0035]
The plasma processing method of the present invention includes a step of installing an object to be processed in a container having a dielectric window capable of transmitting microwaves, a step of exhausting the inside of the container, and a step of introducing a processing gas into the container And a plurality of slots provided in the surface in contact with the dielectric window at a predetermined interval, and n₁The number of antinodes of the surface standing wave generated between the slots, λ_FiveIs the wavelength of the surface wave, n_gThe wavelength λ_gCircumference of the annular waveguide with respect to 1_gThe radius r_eStands for,
r_e= N₁λ_Five/ {2 tan (π / (2n_g))} {1 + cos (π / n_g)}
And a step of generating plasma by supplying a microwave from the annular waveguide into the container using an annular waveguide configured so that the center of the slot exists on the circumference of Features.
[0036]
In one embodiment of the plasma processing method of the present invention, a film is formed on the target object by chemical vapor deposition.
[0037]
In one aspect of the plasma processing method of the present invention, the object to be processed is etched.
[0038]
In one aspect of the plasma processing method of the present invention, an ashing process is performed on the object to be processed.
[0039]
In one aspect of the plasma processing method of the present invention, the object to be processed is subjected to a doping process.
[0040]
The plasma processing apparatus of the present invention has a container that can be evacuated inside, and a gas supply port that supplies a processing gas into the container, and performs plasma processing on an object to be processed disposed in the container In the apparatus, the apparatus has means for supplying microwave energy for generating plasma of the gas in the container, and the means for supplying the microwave energy is provided on the surface on the dielectric window side at a predetermined interval. An endless annular waveguide having a plurality of slots, and n₁The number of antinodes of the surface standing wave generated between the slots, λ_FiveIs the wavelength of the surface wave, n_gThe wavelength λ_gCircumference of the annular waveguide with respect to 1_gThe radius r_eStands for,
r_e= N₁λ_Five/ {2 tan (π / (2n_g))} {1 + cos (π / n_g)}
The centers of the plurality of slots are arranged so as to be offset from the center of the annular waveguide in the direction along the plane so that the centers of the slots exist on the circumference.
[0041]
In one aspect of the plasma processing apparatus of the present invention, n_gThe value of is in the range of 2-5.
[0042]
In one aspect of the plasma processing apparatus of the present invention, the angular interval of the slots is π / n._gIt is.
[0043]
In one aspect of the plasma processing apparatus of the present invention, the number n of antinodes of surface standing waves generated between the slots.₁Is either 3, 5, or 7.
[0044]
In one aspect of the plasma processing apparatus of the present invention, the dielectric window is mainly composed of aluminum nitride.
[0045]
In one aspect of the plasma processing apparatus of the present invention, the gas supply port is provided on a side wall of the container.
[0046]
In one aspect of the plasma processing apparatus of the present invention, the gas supply port is provided closer to the surface on which the plurality of slots are provided than the object to be processed.
[0047]
In one aspect of the plasma processing apparatus of the present invention, the processing gas is discharged from the gas supply port toward the surface provided with the plurality of slots.
[0048]
In one aspect of the plasma processing apparatus of the present invention, the container contains 1.34 × 10 6 inside the container.^ThreeAn exhaust pump capable of reducing the pressure to Pa or lower is provided.
[0049]
The plasma processing method of the present invention is characterized in that, in the plasma processing method for plasma processing a target object, the target object is plasma processed using the plasma processing apparatus.
[0050]
In one embodiment of the plasma processing method of the present invention, at least one of ashing, etching, cleaning, CVD, plasma polymerization, doping, oxidation, and nitriding is used.
[0051]
The structure manufacturing method of the present invention includes a step of plasma processing the object to be processed using the plasma processing apparatus.
[0052]
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 is a schematic cross-sectional view showing a plasma processing apparatus.
The microwave supply device 3 including the annular waveguide 13 having a surface on which a plurality of slots 33 for radiating microwaves is provided has the plurality of slots 33 with respect to the center C1 of the annular waveguide 13. The center C2 is arranged so as to be biased in the direction along the surface.
[0053]
Reference numeral 1 denotes a vacuum vessel that accommodates the object to be processed W and can generate plasma in the plasma generation space 9, and is cut off from the atmosphere by, for example, an open-air vessel or a load lock chamber (not shown) arranged in parallel. It is a container.
[0054]
Reference numeral 2 denotes a target object holding means called a susceptor or holder for accommodating and holding the target object W in the container 1, and has lift pins 12 that can move the target object W up and down. Furthermore, if necessary, the holding means 2 may be provided with a temperature adjusting means such as a heater for heating the object to be processed W or a cooler for cooling the object to be processed.
[0055]
Reference numeral 3 denotes a microwave supply device for supplying microwave energy for generating plasma in the container 1. The position of the slot 33 is offset inward. Incidentally, the slot shown in FIG. 14 is not offset.
[0056]
Reference numeral 4 denotes a dielectric window that hermetically seals the inside of the container 1 and transmits microwaves.
[0057]
5 is a microwave waveguide, and 6 is a microwave power source.
[0058]
Reference numeral 7 denotes a gas supply path for supplying a processing gas that is converted into plasma by microwaves, and has a gas supply port 17 at the tip of the discharge path facing obliquely upward.
[0059]
The gas supply path 7 communicates with a gas supply system 27 such as various gas cylinders 57, valves 47, and a flow rate controller 37.
[0060]
Reference numeral 8 denotes an exhaust passage for exhausting the inside of the container 1 and communicates with an exhaust system including a vacuum pump 18 and a valve 28 through an exhaust port (not shown).
[0061]
FIG. 2 shows a slotted flat plate 23 used in the microwave feeder 3 of the apparatus of FIG.
[0062]
The slotted flat plate 23 has a plurality of slots 33. The slots are unevenly provided in the direction along the surface of the flat plate 23 so that the line connecting the center C2 of the slot is located inward of the ring from the line connecting the center C1 of the annular waveguide 13. C3 indicates the position of the outer surface of the annular waveguide 13, and C4 indicates the position of the inner surface thereof.
[0063]
The plasma processing method using the apparatus of FIG. 1 is as follows. A processing gas is supplied from the gas supply port 17 into the container 1 evacuated and exhausted to a predetermined pressure.
[0064]
The processing gas is discharged into the space 9 serving as a plasma generation chamber and then flows into the exhaust path 8.
[0065]
On the other hand, a microwave generated in a microwave power source 6 such as a magnetron propagates through a waveguide 5 such as a coaxial waveguide, a cylindrical waveguide, or a rectangular waveguide, and is microwaved from an introduction port 15. It is introduced into the feeder 3.
[0066]
The microwave introduced from the upper H surface facing one slot 33 radiates the microwave from the slot 33, and the endless loop of the microwave feeder 3 in the clockwise or counterclockwise direction in FIG. It propagates in the waveguide 13.
[0067]
On the H surface of the annular waveguide 13, for example, TE_TenSince the longitudinal slot 33 intersecting the propagation / travel direction of the microwave propagating / traveling in the road in the mode is provided, the microwave is radiated from the slot 33 toward the space 9.
[0068]
The microwave is supplied to the space 9 through the microwave transmission window 4 made of a dielectric.
[0069]
A processing gas exists in the space 9, and this processing gas is excited by microwave energy to generate plasma. The mechanism of microwave radiation and plasma generation is as described with reference to FIG.
[0070]
The surface of the workpiece W is subjected to surface treatment using this plasma. The plasma P may exist only below the slot as shown in FIG. 1 or spread over the entire lower surface of the window 4 depending on the power of the input microwave and the pressure in the container.
[0071]
Depending on the size of the workpiece W and the circumference of the microwave supply waveguide, the slots can be unevenly distributed outward.
[0072]
FIG. 3 is a schematic cross-sectional view showing the plasma processing apparatus.
[0073]
This apparatus has a slotted flat plate 23 as shown in FIG. The difference from the apparatus shown in FIG. 1 is that a flat plate 23 with a slot shown in FIG. 4 is attached and a bias power source 22 to be processed is attached.
[0074]
The pressure in the space 9 is lowered to adjust the plasma to spread more, and the plasma processing can be performed while applying a bias voltage to the workpiece W from the bias power source 22. Such a configuration is suitable for etching.
[0075]
Furthermore, it is also preferable to attach a cooler to the holding means 2 as needed to suppress the temperature rise of the workpiece W.
[0076]
1 and 2 have the same configuration as the apparatus of the embodiment of FIG.
[0077]
FIG. 4 shows another example of the slotted flat plate of the microwave feeder used in the present invention.
[0078]
4 is different from the flat plate shown in FIG. 2 in that another slot 43 is provided on the extended line of the slot 33 provided in the same manner as in FIG.
[0079]
The outer slot 43 is also provided such that a line C5 connecting the centers thereof is unevenly distributed outward of the ring with respect to a line C1 connecting the centers of the annular waveguides 13.
[0080]
The pair of slots 33 and the slots 43 in the same radial direction are formed in a discontinuous linear shape, so that microwaves can be radiated more uniformly in the radial direction than in the case of the conventional slots. In addition, microwaves can be radiated more uniformly in the circumferential direction (microwave traveling direction) than when the slot 33 and the slot 43 are integrated into a long slot.
[0081]
The amount of eccentricity of the slot used in the present invention is appropriately determined according to the processing conditions used. In particular, if the slotted flat plate 23 is configured to be replaceable with respect to the conductive base material having the concave portion that becomes the waveguide 13, it is possible to flexibly cope with changes in processing conditions.
[0082]
The center of the slot used in the present invention is different from the center of the annular waveguide. The shape of the different center slot is such that the center of each slot is inward and / or outward with respect to the center of the waveguide. If so, a single rectangular perforation or a plurality of perforations having a length of 1/4 to 3/8 of the in-tube wavelength and discontinuously arranged on a straight line can be applied.
[0083]
FIG. 5 is a schematic cross-sectional view of a microwave plasma processing apparatus using a planar annular waveguide with discontinuous linear slots, and FIG. 6 is a top view of the slot plate of the annular waveguide.
The difference from the apparatus shown in FIGS. 3 and 4 is that the size of the annular waveguide (microwave supply) 3 is relatively larger than the size of the object to be processed W, and the gas discharge port 17 is different. The point is directed obliquely downward, and the number of discontinuous linear slots including a pair of slots 33 and 43 unevenly distributed inward and outward is eight. A heater 114 is provided in the holding means 2 for controlling the temperature of the object to be processed.
As the exhaust system and gas supply system, those similar to those shown in FIGS. 1 and 3 can be used.
In FIG. 5, the slots 33 and 43 are omitted.
[0084]
Plasma generation and processing are performed as follows. The inside of the container 1 is evacuated through an exhaust system (not shown). Subsequently, a plasma processing gas is introduced into the container 1 through the gas supply path 7 at a predetermined flow rate. Next, a conductance valve (not shown) provided in the exhaust system (not shown) is adjusted to maintain the inside of the container 1 at a predetermined pressure. Plasma is generated in the container 1 by supplying desired electric power from a microwave power source (not shown) into the container 1 via the microwave supplier 3. The processing gas introduced at this time is excited, dissociated, and ionized by the generated high-density plasma, and the surface of the workpiece W placed on the holding means 2 is processed.
[0085]
The material of the annular waveguide used as the microwave supply device used in the microwave plasma processing apparatus of the present invention can be any conductive material, but Al having high conductivity is used to suppress the propagation loss of the microwave as much as possible. SUS, Cu, Ag / Cu plated SUS, etc. are optimal. The direction of the microwave inlet 15 of the annular waveguide used in the present invention can be introduced in the direction perpendicular to the H plane as shown in the figure as long as the microwave can be efficiently introduced into the waveguide in the microwave feeder. It may be divided into two in the left-right direction of the propagation space at the part, or may be parallel to the H plane and tangential to the propagation space. The slot spacing in the microwave traveling direction of the microwave feeder used in the present invention is optimally ½ of the guide wavelength.
[0086]
In the present invention, the length of each continuous portion of the discontinuous slot, that is, the length of the slot 33 or the slot 43 is preferably ¼ to 3/8 of the guide wavelength. The discontinuous linear slots 33 and 43 face the direction intersecting the microwave traveling direction 121. That is, the longitudinal direction of the slot intersects with the microwave traveling direction 121, and here intersects perpendicularly. Here, the rectangular waveguide is formed into an endless shape (of course, including not only an annular shape but also an elliptical shape, a square shape, a pentagon shape, etc.), and TE_TenMode (H₀₁Mode) microwaves are propagated, and therefore one discontinuous linear slot (a pair of slots) corresponds to one vibration antinode. Reference numeral 120 schematically indicates the direction of the magnetic field.
[0087]
FIG. 7 is a schematic cross-sectional view of a microwave plasma processing apparatus using a tangential introduction type flat annular waveguide.
[0088]
A desired power is introduced into a flat annular waveguide 3 from an introduction port 15 formed on the E plane from a microwave power source (not shown). The introduced microwave is introduced into the plasma generation space 9 through the dielectric window 4 through a slot formed every ½ of the guide wavelength. The microwave propagated once without being introduced interferes with the newly introduced tangential microwave in the vicinity of the introduction port 15 and strengthens, and most of the microwave is introduced into the plasma generation space before propagating several times. .
[0089]
FIG. 7 is also shown with the slot omitted.
Using the microwave plasma processing apparatus shown in FIG. 7, plasma was generated under the conditions of an Ar flow rate of 500 sccm, pressures of 1.33 Pa and 133 Pa, and a microwave power of 3.0 kW, and the obtained plasma was measured. Plasma measurement was performed by the single probe method as follows. The voltage applied to the probe is changed in the range of −50 to +100 V, the current flowing through the probe is measured by an IV measuring instrument, and the electron density, electron temperature, plasma is measured from the obtained IV curve by the method of Langmuir et al. The potential was calculated. As a result, the electron density is 1.9 × 10 3 at 1.33 Pa.¹²/ Cm^Three± 2.7% (in the φ300 plane) 8.7 × 10 at 133 Pa¹¹/ Cm^ThreeIt was ± 5.6% (in the φ300 plane), and it was confirmed that high-density and uniform plasma was formed even in the high-pressure region.
[0090]
FIG. 8 is a schematic cross-sectional view of a microwave plasma processing apparatus using an RF bias applying mechanism. Reference numeral 22 denotes an RF bias applying means. FIG. 8 also shows the slot omitted.
[0091]
Plasma generation and processing are performed as follows. The workpiece W is placed on the holding unit 2 and heated to a desired temperature using the heater 114. The plasma generation space 9 is evacuated through an exhaust system (not shown). Subsequently, a plasma processing gas is introduced into the plasma generation space 9 at a predetermined flow rate. Next, a conductance valve (not shown) provided in the exhaust system (not shown) is adjusted to maintain the plasma generation space at a predetermined pressure. RF power is supplied to the holding means 2 using the RF bias applying means 22, and a desired power from a microwave power source (not shown) is transmitted through the dielectric window 4 through the plate-shaped annular waveguide 3 and plasma. Introduce into the generation space 9. Electrons are accelerated by the introduced microwave electric field, and plasma is generated in the plasma generation space 9. At this time, the processing gas is excited, dissociated, and ionized by the generated high-density plasma, and the surface of the workpiece W is processed. Further, the kinetic energy of ions incident on the substrate can be controlled by the RF bias.
[0092]
FIG. 9 is a schematic cross-sectional view of a microwave plasma processing apparatus with a cooling mechanism for temperature control, and 414 is a cooler for cooling the substrate.
FIG. 9 is also shown with the slot omitted.
[0093]
Plasma generation and processing are performed as follows. The workpiece W is placed on the holding means 2 and cooled using the cooler 414. The plasma generation space 9 is evacuated through an exhaust system (not shown). Subsequently, a plasma processing gas is introduced. Next, a conductance valve (not shown) provided in the exhaust system (not shown) is adjusted to maintain the plasma generation space 9 at a predetermined pressure. RF power is supplied to the holding means 2 using the RF bias applying means 22, and a desired power from a microwave power source (not shown) is transmitted through the dielectric window 4 through the plate-shaped annular waveguide 3 and plasma. Introduce into the generation space. Electrons are accelerated by the introduced microwave electric field, and plasma is generated. By using the cooler 414, it is possible to suppress overheating of the substrate due to ion incidence, which becomes a problem when high-density plasma and a high bias are used.
[0094]
The annular waveguide used in the present invention is not limited to an annular shape as long as it is annular as described above, and may have various shapes such as an elliptical annular shape, a rectangular annular shape, and a pentagonal annular shape.
When processing a disk-shaped object such as a semiconductor wafer, an optical disk or a magnetic disk, an annular shape is preferable.
[0095]
As the microwave feeder having an annular waveguide used in the present invention, it is also preferable to use an assembly of a conductive base material having an annular recess serving as a waveguide and a flat plate with a slot.
[0096]
It is also preferable to fill the waveguide with a dielectric to shorten the guide wavelength as required. As such a dielectric, a resin such as tetrafluoroethylene is preferably used. The slot position in the present invention is set as described later.
[0097]
(First embodiment)
First, the first embodiment will be described. 16 (a) to 16 (c) are schematic diagrams showing a microwave plasma processing apparatus. FIG. 16A is a cross-sectional view of the apparatus, FIG. 16B is a plan view of a microwave supply device, and FIG. 16C is a schematic diagram showing a state of microwave propagation.
[0098]
Here, 1 is a container constituting the plasma processing chamber, W is an object to be processed, 2 is a support for the object to be processed W, 114 is a means for adjusting the temperature of the object to be processed W, 22 is a high-frequency bias applying means, 7 Is a processing gas supply port, 18 is an exhaust pump, 28 is an exhaust conductance adjusting valve, 4 is a dielectric window that separates the plasma processing chamber from the atmosphere side, and 3 is a microwave passing through the dielectric window 4 into the plasma processing chamber. A microwave feeder comprising a slotted endless annular waveguide for introduction, 13 a microwave waveguide in the endless annular waveguide, 15 a right and left distribution of the microwave introduced into the endless annular waveguide The microwave introduction port constituting the E branch, STW is a standing wave generated by interference between the microwaves propagated in the waveguide distributed by the E branch, and 33 is a surface in contact with the dielectric window 4 (here, H side) for a predetermined period In a plurality of slots provided it is perforated.
[0099]
SW is a surface wave propagating on the surface of the dielectric 4 introduced through the slot 33, and SSTW is a surface standing wave generated by interference between the surface waves SW emitted from the adjacent slots 33. Plasma is called surface wave interference plasma because it is generated below the dielectric window by electronic excitation by the surface standing wave SSTW.
[0100]
Here, the slot 33 is not the center of the microwave waveguide 13 in the endless annular waveguide, but n₁The number of antinodes of the surface standing wave SSTW generated between the slots 33, λ_FiveIs the wavelength of the surface wave SW, n_gThe wavelength λ_gCircumference l of the circular waveguide 13 with respect to_gAs the magnification of
Radius r_eStands for,
r_e= N₁λ_Five/ {2 tan (π / (2n_g))} {1 + cos (π / n_g)}
The center of the slot 33 exists on the circumference C2 that is.
[0101]
The reason for this will be described with reference to FIG.
When it can be approximated that an odd number of surface standing waves SSTW are generated between the slots 33 in parallel with the arrangement direction of the slots due to interference between the surface waves SW generated from the adjacent slots 33, the surface standing wave SSTW is The wavelength λ of the surface wave SW_FiveOccurs at intervals of 1/2. Therefore, in order to generate the surface standing wave SSTW at equal intervals most efficiently, the propagation length of the surface wave SW between the slots (which is equal to the central standing wave interval L) is:
L = n₁λ_Five/ 2
It is necessary to. In the general case where the arrangement direction of the slots and the arrangement direction of the generated surface standing waves SSTW cannot be approximated as parallel,
L = n₁λ_Five/ {1 + cos (π / n_g)}
It is necessary to replace with.
[0102]
The propagation length L is the radius r of the circumference where the slot center should exist._eAnd the half angle θ between the slots,
L = 2r_etanθ
= 2r_etan (π / (2n_g)
(In this case, the angular spacing of the slots is π / n_gBecomes). Therefore, the radius r of the circumference where the slot center should exist_eIs
r_e= N₁λ_Five/ {2 tan (π / (2n_g))} {1 + cos (π / n_g)}
It is expressed.
[0103]
Where n_g(= 1_g/ Λ_g) Is preferably in the range of 2-5. The number n of antinodes of the surface standing wave SSTW generated between the slots 33₁Is preferably any of 3, 5 and 7.
[0104]
As an example, the number n of surface standing waves between slots₁: 3, 5, microwave frequency 2.45 GHz (λ₀: 22.44 mm), n_g: 2, 3, 4 Dielectric window: Quartz glass (ε_w: 3.8), aluminum nitride (ε_w: 9.8) shows the slot center radius in Table 1 below.
[0105]
[Table 1]

[0106]
Plasma generation and processing are performed as follows.
First, the plasma processing chamber is evacuated through the exhaust means 18.
Subsequently, the plasma processing gas is introduced into the plasma processing chamber through the processing gas supply port 7 at a predetermined flow rate.
[0107]
Next, conductance adjusting means 28 provided between the plasma processing chamber and the exhaust pump 18 is adjusted to keep the plasma processing chamber at a predetermined pressure. If necessary, a bias is applied to the workpiece W via the high frequency bias applying means 22. A desired power is supplied from the microwave power source MW to the plasma processing chamber via the endless annular waveguide 13.
[0108]
At this time, the TE introduced into the endless annular waveguide 13_TenThe mode microwave is divided into left and right at the E branch of the introduction port 15 and propagates in the waveguide 13 with an in-path wavelength longer than the free space. The distributed microwaves interfere with each other to generate a standing wave STW having an “antinode” every ½ of the guide wavelength. The plasma passes through the dielectric window 4 from the slot 33 provided at the position where the current flowing through the conductive surface of the waveguide, here the H-plane, becomes maximum, that is, between the two adjacent antinodes. The microwave introduced into the processing chamber generates plasma near the slot 33. The electron plasma frequency of the generated plasma exceeds the power supply frequency (for example, the electron density is 7 × 10^Ten/ Cm^ThreeIf the electron plasma frequency exceeds the power frequency of 2.45 GHz), the microwave cannot propagate in the plasma (so-called cutoff), and the electron density further increases.
δ = (2 / ωμ₀σ)^1/2
[Ω: power supply angular frequency, μ₀: Vacuum permeability, σ: Plasma conductivity]
Is sufficiently thin (for example, the electron density is 2 × 10¹²cm^-3When the thickness is as described above, the skin thickness is 4 mm or less), and the surface of the dielectric window 4 propagates as the surface wave SW.
[0109]
The surface waves SW introduced from the adjacent slots 33 interfere with each other,
λ_Five= Λ₀ε_r ^-1/2
[Λ₀: Free-space microwave wavelength, ε_r: Dielectric relative permittivity]
The surface standing wave SSTW is generated every half of the wavelength of the surface wave SW represented by
[0110]
Electrons are accelerated by this surface standing wave SSTW that has oozed into the plasma processing chamber, and surface-wave interfering plasma (SIP) is generated. At this time, if the processing gas is introduced into the plasma processing chamber via the processing gas supply port 7, the processing gas is excited by the generated high-density plasma, and the surface of the workpiece W placed on the support 2. Process.
[0111]
The shape of the slot 33 used in the microwave plasma processing apparatus of this embodiment is substantially the center of the slot 33,
r_e= N₁λ_Five/ {2 tan (π / (2n_g))} {1 + cos (π / n_g)}
If it exists in the position C2 represented by this, even if it is not the rectangular perforation whose length is 1/4 to 3/8 of the in-tube wavelength, it is applicable.
[0112]
(Second Embodiment)
In the microwave plasma processing apparatus of the present invention, n_gIs 3, number of surface standing waves between slots n₁Is 3, and the dielectric is quartz glass (dielectric constant ε_r: 3.8) shows the microwave feeder in FIG. The configuration of the apparatus main body is almost the same as that shown in FIG.
[0113]
Here, the slot 33 is formed so that the center of the slot exists on a circumference C5 having a radius of about 103.9 mm, outside the center of the microwave waveguide 13 in the endless annular waveguide.
[0114]
At this time, TE introduced into the endless annular waveguide_TenThe mode microwave is divided into left and right by the E branch, and propagates in the waveguide 13 with an in-tube wavelength longer than the free space. The distributed microwaves interfere with each other and generate standing waves having six “antinodes” for every half of the path wavelength. The microwave introduced into the plasma processing chamber through the dielectric window from the position where the current is maximized, that is, in the center between the two adjacent “antinodes” through the dielectric window, Generate.
[0115]
The electron plasma frequency of the generated plasma exceeds the power supply frequency (for example, the electron density is 7 × 10^Ten/ Cm^ThreeIf the electron plasma frequency exceeds the power frequency of 2.45 GHz), the microwave cannot propagate in the plasma (so-called cutoff), and the electron density further increases.
δ = (2 / ωμ₀σ)^1/2
[Ω: power supply angular frequency, μ₀: Vacuum permeability, σ: Plasma conductivity]
Is sufficiently thin (for example, the electron density is 2 × 10¹²cm^-3Then, the skin thickness is 4 mm or less), and the surface of the quartz dielectric is propagated as a surface wave.
[0116]
Surface waves introduced from adjacent slots 33 interfere with each other, and surface standing waves are generated every about 31 mm. Electrons are accelerated by the surface standing waves that have oozed into the plasma processing chamber, and surface wave interference plasma is generated.
[0117]
The material of the dielectric window is anhydrous synthetic quartz, the diameter is 300 mm, and the thickness is 12 mm. The endless annular waveguide has an internal waveguide cross-sectional dimension of 27 mm × 96 mm and a center diameter of 152 mm (waveguide circumference l_gIs the wavelength λ_g3 times).
[0118]
Al is used as the material for the endless annular waveguide in order to suppress the propagation loss of microwaves. A slot 33 for introducing a microwave into the plasma processing chamber is formed on the H surface of the endless annular waveguide. The slots 33 have a rectangular shape with a length of 40 mm and a width of 4 mm, the center is on a circumference C5 having a radius of 103.9 mm, and a total of six slots 33 are formed radially at intervals of 60 °. A 4E tuner, a directional coupler, an isolator, and a microwave power source (not shown) having a frequency of 2.45 GHz are sequentially connected to the endless annular waveguide.
[0119]
Using the plasma processing apparatus having the microwave supply device shown in FIG. 18, plasma is generated under the conditions of an Ar flow rate of 500 sccm, a pressure of 1.33 Pa, and a microwave power of 3.0 kW, and the obtained plasma is measured. It was. Plasma measurement was performed by the single probe method as follows. The voltage applied to the probe is changed in the range of −50 to +100 V, the current flowing through the probe is measured by an IV measuring instrument, and the electron density, electron temperature, plasma is measured from the obtained IV curve by the method of Langmuir et al. The potential was calculated. As a result, the electron density is 2.1 × 10 3 at 1.33 Pa.¹²cm^-3It was ± 2.7% (φ300 in-plane), and it was confirmed that a stable plasma with a high electron density was formed even in a low pressure region.
[0120]
(Third embodiment)
In the microwave plasma processing apparatus of the present invention, the waveguide circumference / in-tube wavelength magnification n_gIs 3, number of surface standing waves between slots n₁Is 3, and the dielectric is AIN (dielectric constant ε_wFIG. 19 shows an example of the microwave feeder in the case of 9.8). The configuration of the apparatus main body is the same as that shown in FIG.
[0121]
Here, the slot 33 is formed with an offset so that the center of the slot exists on a circumference C2 having a radius of approximately 67.7 mm, which is inside the center of the microwave waveguide 13 in the endless annular waveguide. Yes.
[0122]
TE introduced into an endless annular waveguide_TenThe mode microwave is divided into left and right by the E branch, and propagates in the waveguide 13 with an in-path wavelength longer than the free space. The distributed microwaves interfere with each other, and a standing wave is generated every half of the path wavelength. The microwave introduced into the plasma processing chamber through the AlN dielectric window 4 from the slot 33 installed at the center between the two standing waves adjacent to the position where the current is maximized is in the vicinity of the slot 33. To generate plasma. The electron plasma frequency of the generated plasma exceeds the power supply frequency (for example, the electron density is 7 × 10^Tencm^-3If the electron plasma frequency exceeds the power frequency of 2.45 GHz), the microwave cannot propagate in the plasma (so-called cutoff), and the electron density further increases.
δ = (2 / ωμ₀σ)^1/2
[Ω: power supply angular frequency, μ₀: Vacuum permeability, σ: Plasma conductivity]
Is sufficiently thin (for example, the electron density is 2 × 10¹²cm^-3Then, the skin thickness is 4 mm or less), and the surface of the dielectric window 4 propagates as a surface wave.
[0123]
Surface waves introduced from adjacent slots 33 interfere with each other, and a surface standing wave is generated about every 20 mm. Surface wave interference plasma in which electrons are accelerated is generated by this surface standing wave that oozes into the plasma processing chamber.
[0124]
The dielectric window 4 made of AlN has a diameter of 300 mm and a thickness of 12 mm. The endless annular waveguide has an internal waveguide cross-sectional dimension of 27 mm × 96 mm and a center diameter of 152 mm (waveguide circumference l_gIs the wavelength λ_g3 times). Al is used as the material for the endless annular waveguide in order to suppress the propagation loss of microwaves.
[0125]
A slot 33 for introducing a microwave into the plasma processing chamber is formed on the H surface of the endless annular waveguide. The slots 33 have a rectangular shape with a length of 40 mm and a width of 4 mm, the center is on a circumference C2 having a radius of 67.7 mm, and a total of six slots 33 are formed radially at intervals of 60 °. A 4E tuner, a directional coupler, an isolator, and a microwave power source having a frequency of 2.45 GHz are sequentially connected to the endless annular waveguide.
[0126]
Using the plasma processing apparatus having the microwave supply device shown in FIG. 19, plasma is generated under the conditions of an Ar flow rate of 500 sccm, a pressure of 1.33 Pa, and a microwave power of 3.0 kW, and the obtained plasma is measured. It was. Plasma measurement was performed by the single probe method as follows. The voltage applied to the probe is changed in the range of −50 to +100 V, the current flowing through the probe is measured by an IV measuring instrument, and the electron density, electron temperature, plasma is measured from the obtained IV curve by the method of Langmuir et al. The potential was calculated. As a result, when the electron density is 1.33 Pa, 1.9 × 10¹²cm^-3It was ± 3.1% (in the φ300 plane), and it was confirmed that a stable plasma with a high electron density was formed even in the low pressure region.
[0127]
(Fourth embodiment)
In the microwave plasma processing apparatus of the present invention, the waveguide circumference / in-tube wavelength magnification n_gIs 4, number n of surface standing waves between slots₁Is 3 and 5, and the dielectric is AlN (dielectric constant ε_w: 9.8) An example of a microwave feeder in the case of 9.8) is shown in FIG. The configuration of the apparatus main body is the same as that of the other apparatus in FIG.
[0128]
Here, the slot 33 includes the center inside and outside of the microwave waveguide 13 in the endless annular waveguide, that is, on the circumference C2 having a radius of about 82.9 mm and the circumference having a radius of about 127.2 mm. The pair of slots 33 are formed in a straight line so that the centers of the pair of slots 33 exist on C5.
[0129]
At this time, TE introduced into the endless annular waveguide_TenThe mode microwave is divided into left and right at the E branch, and propagates through the waveguide with an in-path wavelength longer than free space.
[0130]
The distributed microwaves interfere with each other, and a standing wave is generated in the waveguide every ½ of the wavelength in the path. The microwave introduced into the plasma processing chamber through the dielectric window 4 from the slot 33 installed at the center between the two standing waves adjacent to the position where the current is maximized, Generate. The electron plasma frequency of the generated plasma exceeds the power supply frequency (for example, the electron density is 7 × 10^Tencm^-3If the electron plasma frequency exceeds the power frequency of 2.45 GHz), the microwave cannot propagate in the plasma (so-called cutoff), and the electron density further increases.
δ = (2 / ωμ₀σ)^1/2
[Ω: power supply angular frequency, μ₀: Vacuum permeability, σ: Plasma conductivity]
Is sufficiently thin (for example, the electron density is 2 × 10¹²cm^-3If it becomes above, the skin thickness will be 4 mm or less), and the surface of the dielectric window propagates as a surface wave.
[0131]
Surface waves emitted from the adjacent slots 33 interfere with each other, and surface standing waves are generated about every 20 mm. Surface wave interference plasma in which electrons are accelerated is generated by this surface standing wave that oozes into the plasma processing chamber.
[0132]
The dielectric window made of AlN has a diameter of 350 mm and a thickness of 13 mm. The endless annular waveguide has an internal waveguide cross-sectional dimension of 9 mm × 96 mm and a center diameter of 202 mm (waveguide circumferential length is four times the in-path wavelength). Al is used as the material for the endless annular waveguide in order to suppress the propagation loss of microwaves.
[0133]
A slot 33 for introducing a microwave into the plasma processing chamber is formed on the H surface of the endless annular waveguide. The slot 33 has a rectangular shape with a length of 40 mm and a width of 4 mm on the circumference C2 with an inner radius of 82.9 mm, and a slot with a length of 46 mm on the circumference C5 with an outer radius of 127.2 mm. It is a rectangular shape with a width of 4 mm, and is formed in a total of six sets of 8 sets radially at 45 ° intervals. A 4E tuner, a directional coupler, an isolator, and a microwave power source MW having a frequency of 2.45 GHz are sequentially connected to the endless annular waveguide.
[0134]
Plasma was generated under the conditions of an Ar flow rate of 500 sccm, a pressure of 10 mTorr, and a microwave power of 3.0 kW using the plasma processing apparatus having the microwave supply shown in FIG. 20, and the obtained plasma was measured. Plasma measurement was performed by the single probe method as follows. The voltage applied to the probe is changed in the range of −50 to +100 V, the current flowing through the probe is measured by an IV measuring instrument, and the electron density, electron temperature, plasma is measured from the obtained IV curve by the method of Langmuir et al. The potential was calculated. As a result, when the electron density is 1.33 Pa, 1.9 × 10¹²cm^-3It was ± 2.2% (in the φ300 plane), and it was confirmed that stable plasma with a high electron density was formed even in the low pressure region.
[0135]
The amount of eccentricity of the slot used in the present invention is appropriately determined according to the processing conditions used as described above. In particular, if the slotted flat plate 23 is configured to be replaceable, it can flexibly cope with changes in processing conditions.
[0136]
The center of the slot used in the present invention is different from the center of the annular waveguide. As described above, the center of each slot is inward and / or outward with respect to the center of the waveguide. If it is unevenly distributed, a single rectangular perforation or a plurality of perforations having a length of 1/4 to 3/8 of the in-tube wavelength and discontinuously arranged on a straight line can be applied. .
[0137]
The slotted flat plate and the annular waveguide used in the present invention can be used as long as they are conductors. However, Al, Cu, and Ag / Cu plated with high conductivity are used to suppress the propagation loss of microwaves as much as possible. Stainless steel is best. The direction of the introduction port to the annular waveguide used in the present invention is such that the microwave can be efficiently introduced into the microwave propagation space in the annular waveguide. The direction in which microwaves can be introduced in parallel with each other, or the direction in which the microwaves can be introduced perpendicularly to the H plane, such as an E plane T branch, may be employed. Further, a distributor as shown by reference numeral 10 in FIG. 15 may be provided in the vicinity of the inlet. The slot spacing in the microwave traveling direction used in the present invention is optimally 1/2 or 1/4 of the guide wavelength.
[0138]
The microwave frequency used in the present invention can be appropriately selected from the range of 0.8 GHz to 20 GHz.
[0139]
Examples of the dielectric material of the microwave transmission window used in the present invention include quartz glass and SiO.₂Other glass, Si_ThreeN_Four, NaCl, KCl, LiF, CaF₂, BaF₂, Al₂O_ThreeInorganic materials such as AlN and MgO are suitable, but organic films and sheets such as polyethylene, polyester, polycarbonate, cellulose acetate, polypropylene, polyvinyl chloride, polyvinylidene chloride, polystyrene, polyamide, and polyimide are also applicable. .
[0140]
In the microwave plasma processing apparatus and processing method of the present invention, magnetic field generating means may be used. As the magnetic field used in the present invention, a mirror magnetic field or the like can also be applied. However, the magnetic flux density of the magnetic field near the slot is optimally a magnetron magnetic field larger than the magnetic flux density of the magnetic field near the substrate. As the magnetic field generating means, a permanent magnet can be used in addition to the coil. When using a coil, other cooling means such as a water cooling mechanism or air cooling may be used to prevent overheating.
[0141]
Moreover, you may irradiate the to-be-processed object surface for the quality improvement of a process. As the light source, any light source that emits light absorbed by the object to be processed or a gas attached thereon can be used, and an excimer laser, an excimer lamp, a rare gas resonance line lamp, a low-pressure mercury lamp, or the like is suitable.
[0142]
The pressure in the plasma processing chamber of the present invention is 1.33 × 10^-2Pa to 1.33 × 10^ThreeIn the range of Pa, more preferably 1.33 × 10 in the case of CVD^-1Pa to 1.33 × 10¹Pa, 6.65 × 10 for etching^-2Pa to 6.65 Pa, ashing 1.33 × 10¹From Pa to 1.33 × 10^ThreeIt can be selected from the range of Pa.
[0143]
The plasma processing method according to the present invention will be described with reference to FIGS. 10 (a) to 10 (e).
[0144]
As shown in FIG. 10A, an inorganic material such as silicon oxide, silicon nitride, silicon nitride oxide, aluminum oxide, or tantalum oxide is formed on the surface of the object 101 such as a silicon substrate by a CVD apparatus or a surface modification apparatus, An insulating film 102 made of an organic material such as tetrafluoroethylene or polyaryl ether is formed.
[0145]
As shown in FIG. 10B, a photoresist is applied and baked to form a photoresist layer 103.
[0146]
As shown in FIG. 10C, a hole pattern latent image is formed by an exposure apparatus, and this is developed to form a photoresist pattern 103 ′ having holes 104.
[0147]
As shown in FIG. 10D, holes 105 are formed by etching the insulating film 102 under the photoresist pattern 103 'by an etching apparatus.
[0148]
As shown in FIG. 10E, the photoresist pattern 103 'is removed by ashing using an ashing apparatus.
[0149]
Thus, a structure having an insulating film with holes is obtained.
[0150]
Subsequently, when depositing a conductor or the like in the hole, it is also preferable to clean the inside of the hole with a cleaning device or the like in advance.
[0151]
The plasma processing apparatus according to the present invention described with reference to FIGS. 1 to 9 is used as at least one of a CVD apparatus, a surface modification apparatus, an etching apparatus, and an ashing apparatus used in the above-described steps. Is possible.
[0152]
FIG. 11A to FIG. 11C show another plasma processing method according to the present invention.
[0153]
As shown in FIG. 11 (a), a conductor pattern made of a metal such as aluminum, copper, molybdenum, chromium, tungsten, or various alloys containing at least one of these metals as a main component, or polycrystalline silicon. A pattern (here, line and space) is formed.
[0154]
As shown in FIG. 11B, an insulating film 107 is formed by a CVD apparatus or the like.
[0155]
After forming a photoresist pattern (not shown), a hole 108 is formed in the insulating film 107 with an etching apparatus.
[0156]
When the photoresist pattern is removed by an ashing device or the like, a structure as shown in FIG. 11C is obtained.
[0157]
The plasma processing apparatus of the present invention can be used as the above-described CVD apparatus, etching apparatus, and ashing apparatus, but is not limited to these as described later.
[0158]
Formation of the deposited film by the microwave plasma processing method of the present invention is performed by appropriately selecting the gas to be used._ThreeN_Four, SiO₂, Ta₂O_Five, TiO₂, TiN, Al₂O_Three, AlN, MgF₂Insulating films such as fluorocarbon, semiconductor films such as a-Si, poly-Si, SiC, and GaAs, metal films such as Al, W, Mo, Ti, and Ta, amorphous carbon, diamond-like carbon, diamond, etc. A deposited film can be formed efficiently.
[0159]
The substrate of the object to be processed to be processed by the plasma processing method of the present invention may be a semiconductor, a conductive one, or an electrically insulating one. Specific examples include semiconductor substrates such as Si wafers and SOI wafers.
[0160]
Examples of the conductive substrate include metals such as Fe, Ni, Cr, Al, Mo, Au, Nb, Ta, V, Ti, Pt, and Pb, or alloys thereof, such as brass and stainless steel.
[0161]
As an insulating substrate, quartz glass and other various glasses, Si_ThreeN_Four, NaCl, KCl, LiF, CaF₂, BaF₂, Al₂O_Three, AlN, MgO and other inorganic materials, polyethylene, polyester, polycarbonate, cellulose acetate, polypropylene, polyvinyl chloride, polyvinylidene chloride, polystyrene, polyamide, polyimide, and other organic films and sheets.
[0162]
As a gas used when a thin film is formed on a substrate by a CVD method, generally known gases can be used.
[0163]
As a source gas containing Si atoms when forming a Si-based semiconductor thin film such as a-Si, poly-Si, or SiC, SiH_Four, Si₂H₆Inorganic silanes such as tetraethylsilane (TES), tetramethylsilane (TMS), dimethylsilane (DMS), dimethyldifluorosilane (DMDFS), dimethyldichlorosilane (DMDCS), etc., SiF_Four, Si₂F₆, Si_ThreeF₈, SiHF_Three, SiH₂F₂, SiCl_Four, Si₂Cl₆, SiHCl_Three, SiH₂Cl₂, SiH_ThreeCl, SiCl₂F₂And those that are in a gas state at normal temperature and pressure or can be easily gasified. In this case, as an additive gas or carrier gas that may be introduced by mixing with the Si source gas, H₂, He, Ne, Ar, Kr, Xe, and Rn.
[0164]
Si_ThreeN_Four, SiO₂As a raw material containing Si atoms when forming a Si compound-based thin film such as SiH_Four, Si₂H₆Inorganic silanes such as tetraethoxysilane (TEOS), tetramethoxysilane (TMOS), octamethylcyclotetrasilane (OMCTS), dimethyldifluorosilane (DMDFS), dimethyldichlorosilane (DMDCS), and other organic silanes, SiF_Four, Si₂F₆, Si_ThreeF₈, SiHF_Three, SiH₂F₂, SiCl_Four, Si₂Cl₆, SiHCl_Three, SiH₂Cl₂, SiH_ThreeCl, SiCl₂F₂And halogenated silanes such as those that are in a gas state at normal temperature and pressure, or those that can be easily gasified. In this case, the nitrogen source gas or oxygen source gas introduced at the same time is N₂, NH_Three, N₂H_Four, Hexamethyldisilazane (HMDS), O₂, O_Three, H₂O, NO, N₂O, NO₂Etc.
[0165]
As raw materials containing metal atoms for forming a metal thin film such as Al, W, Mo, Ti, Ta, etc., trimethylaluminum (TMAl), triethylaluminum (TEAl), triisobutylaluminum (TIBAl), dimethylaluminum hydride ( DMAlH), tungsten carbonyl (W (CO)₆), Molybdenum carbonyl (Mo (CO)₆), Organic metals such as trimethylgallium (TMGa) and triethylgallium (TEGa), AlCl_Three, WF₆, TiCl_Three, TaCl_FiveAnd metal halides. In this case, as an additive gas or carrier gas that may be introduced by mixing with the Si source gas, H₂, He, Ne, Ar, Kr, Xe, and Rn.
[0166]
Al₂O_Three, AlN, Ta₂O_Five, TiO, TiN, WO_ThreeThe raw materials containing metal atoms when forming a metal compound thin film such as trimethylaluminum (TMAl), triethylaluminum (TEAl), triisobutylaluminum (TIBAl), dimethylaluminum hydride (DMAlH), tungsten carbonyl (W ( CO)₆), Molybdenum carbonyl (Mo (CO)₆), Organic metals such as trimethylgallium (TMGa) and triethylgallium (TEGa), AlCl_Three, WF₆, TiCl_Three, TaCl_FiveAnd metal halides. In this case, the oxygen source gas or the nitrogen source gas introduced simultaneously is O₂, O_Three, H₂O, NO, N₂O, NO₂, N₂, NH_Three, N₂H_Four, Hexamethyldisilazane (HMDS) and the like. When forming a carbon film such as amorphous carbon, diamond-like carbon, diamond, etc., CH_Four, C₂H₆When a fluorocarbon film is formed using a carbon-containing gas such as_FourOr C₂F₆It is recommended to use a fluorine-containing gas such as carbon.
[0167]
As an etching gas for etching the substrate surface, F₂, CF_Four, CH₂F₂, C₂F₆, C_FourF₈, CF₂Cl₂, SF₆, NF_Three, Cl₂, CCl_Four, CH₂Cl₂, C₂Cl₆Etc.
[0168]
When ashing and removing organic components such as photoresist on the substrate surface, the ashing gas is O₂, O_Three, H₂O, N₂, NO, N₂O, NO₂Etc.
[0169]
Further, when the microwave plasma processing apparatus and the processing method of the present invention are applied to surface modification, for example, Si, Al, Ti, Zn, Ta or the like is used as a substrate or a surface layer by appropriately selecting a gas to be used. Then, oxidation treatment or nitridation treatment of these substrates or surface layers, and further doping treatment of B, As, P, etc. are possible. Furthermore, the present invention can be applied to a cleaning method. In that case, it can also be used for cleaning to remove oxides, organic substances, heavy metals, and the like.
[0170]
As an oxidizing gas when the substrate is subjected to an oxidation surface treatment, O₂, O_Three, H₂O, NO, N₂O, NO₂Etc. Further, as a nitriding gas when the substrate is nitrided, N₂, NH_Three, N₂H_Four, Hexamethyldisilazane (HMDS) and the like.
[0171]
As a cleaning / ashing gas for cleaning organic substances on the substrate surface or for ashing and removing organic components on the substrate surface such as photoresist, O₂, O_Three, H₂O, H₂, NO, N₂O, NO₂Etc. Further, as a cleaning gas for cleaning the inorganic substance on the substrate surface, F₂, CF_Four, CH₂F₂, C₂F₆, C_FourF₈, CF₂Cl₂, SF₆, NF_ThreeEtc.
[0172]
【Example】
Example 1
Photoresist ashing was performed using the microwave plasma processing apparatus shown in FIGS.
As an object to be processed, interlayer SiO₂The silicon (Si) substrate (φ8 inch) immediately after the film was etched and the via hole was formed was used.
[0173]
First, the Si substrate is placed on the support 2 and the Si substrate is heated to 250 ° C. using a heater as the temperature adjusting means 114, and then the plasma processing chamber is evacuated through an exhaust system to obtain 1.33 × 10^-3The pressure was reduced to Pa. Oxygen gas was introduced into the plasma processing chamber through the plasma processing gas supply port 7 at a flow rate of 500 sccm.
[0174]
Next, a conductance valve 28 provided between the plasma processing chamber and the exhaust pump 18 was adjusted to maintain the processing chamber at 40 Pa. The plasma processing chamber was supplied with power of 1.5 kW from a microwave power source MW of 2.45 GHz via an endless annular waveguide.
[0175]
Thus, plasma was generated in the plasma processing chamber. At this time, the oxygen gas introduced through the plasma processing gas supply port 7 is excited, decomposed, and reacted in the plasma processing chamber to form oxygen radicals, which are transported in the direction of the Si substrate and oxidize the photoresist on the Si substrate. The exhaust system was discharged and removed. After ashing, ashing speed and substrate surface charge density were evaluated.
[0176]
The obtained ashing speed and uniformity were very good at 5.6 μm / min ± 4.5%, and the surface charge density was −1.3 × 10 6.¹¹cm^-2And a sufficiently low value.
[0177]
(Example 2)
Photoresist ashing was performed using the plasma processing apparatus having the microwave supplier shown in FIG.
As the object to be processed W, interlayer SiO₂The silicon (Si) substrate (φ8 inch) immediately after the film was etched and the via hole was formed was used.
[0178]
First, after setting the Si substrate on the support 2, the plasma processing chamber is evacuated through an exhaust system to obtain 1.33 × 10 6.^-3The pressure was reduced to Pa. Oxygen gas was introduced into the plasma processing chamber through the plasma processing gas supply port at a flow rate of 1 slm.
[0179]
Next, a conductance valve 28 provided between the plasma processing chamber and the exhaust pump 18 was adjusted to maintain the processing chamber at 80 Pa. In the plasma processing chamber, 1.5kW TE from a 2.45GHz microwave power source_TenMode microwave power was supplied through an endless annular waveguide.
[0180]
Thus, plasma was generated in the plasma processing chamber. At this time, the oxygen gas introduced through the plasma processing gas supply port 7 is excited, decomposed, and reacted in the plasma processing chamber to become oxygen radicals, which are transported in the direction of the Si substrate, oxidizing the photoresist on the substrate, Vaporized and removed. After ashing, ashing speed and substrate surface charge density were evaluated.
[0181]
The obtained ashing speed and uniformity were as extremely large as 5.4 μm / min ± 3.4%, and the surface charge density was −1.4 × 10.¹¹cm^-2And a sufficiently low value.
[0182]
(Example 3)
Using the microwave plasma processing apparatus shown in FIGS. 16A to 16C, a silicon nitride film for protecting a semiconductor element was formed.
The object to be processed is an interlayer SiO in which an Al wiring pattern (line and space 0.5 μm) is formed.₂A P-type single crystal silicon substrate with a film (plane orientation <100>, resistivity 10 Ωcm) was used.
[0183]
First, after the silicon substrate is placed on the support base 2, the plasma processing chamber is evacuated through an exhaust system to obtain 1.33 × 10 6.^-FiveThe pressure was reduced to a value of Pa.
[0184]
Next, the heater 114 as a temperature adjusting means was energized, the silicon substrate was heated to 300 ° C., and the substrate was kept at this temperature. Nitrogen gas was introduced into the treatment chamber through the plasma treatment gas supply port at a flow rate of 600 sccm and monosilane gas at a flow rate of 200 sccm.
[0185]
Next, the conductance valve 18 provided between the plasma processing chamber and the exhaust pump 18 was adjusted to maintain the processing chamber at 2.67 Pa.
[0186]
Next, 3.0 kW of power was supplied from the 2.45 GHz microwave power source MW via the endless annular waveguide.
[0187]
Thus, plasma was generated in the plasma processing chamber. At this time, the oxygen gas introduced through the plasma processing gas supply port 7 is excited and decomposed in the plasma processing chamber to become active species, transported in the direction of the silicon substrate, reacts with the monosilane gas, and the silicon nitride film becomes the silicon substrate. It was formed with a thickness of 1.0 μm on top.
[0188]
After film formation, film quality such as film formation speed and stress was evaluated. The stress was determined by measuring the change in the amount of warpage of the substrate before and after film formation with a laser interferometer Zygo (trade name).
The film formation rate and uniformity of the obtained silicon nitride film are extremely large at 530 nm / min ± 3.5%, and the film quality is also stress 1.2 × 10.⁹dyne / cm²(Compression), leakage current 1.2 × 10^-TenA / cm²It was confirmed that the film was a very good film having a dielectric strength of 9 MV / cm.
[0189]
Example 4
Using the plasma processing apparatus having the microwave supply device shown in FIG. 19, the plastic lens antireflection silicon oxide film and silicon nitride film were formed.
A plastic convex lens with a diameter of 50 mm was used as the object to be processed. After installing the lens on the support 2, the plasma processing chamber is evacuated through an exhaust system to obtain 1.33 × 10 6.^-FiveThe pressure was reduced to a value of Pa. Nitrogen gas was introduced into the processing chamber through the plasma processing gas supply port 7 at a flow rate of 160 sccm and monosilane gas at a flow rate of 100 sccm.
[0190]
Next, a conductance valve 28 provided between the plasma processing chamber and the exhaust pump 18 was adjusted to maintain the processing chamber at 9.33 Pa.
[0191]
Next, 3.0 kW of electric power was supplied from a 2.45 GHz microwave power source MW to the plasma processing chamber via an endless annular waveguide.
[0192]
Thus, plasma was generated in the plasma processing chamber. At this time, the nitrogen gas introduced through the plasma processing gas supply port is excited and decomposed in the plasma processing chamber to become active species such as nitrogen atoms, transported in the direction of the lens, reacts with the monosilane gas, and the silicon nitride film Was formed on the lens with a thickness of 21 nm.
[0193]
Next, oxygen gas was introduced into the treatment chamber through the plasma treatment gas supply port at a flow rate of 200 sccm and monosilane gas at a flow rate of 100 sccm.
[0194]
Next, a conductance valve 28 provided between the plasma processing chamber and the exhaust pump 18 was adjusted to maintain the processing chamber at 0.13 Pa. Next, 2.0 kW of power was supplied from a 2.45 GHz microwave power source MW to the plasma processing chamber via an endless annular waveguide.
[0195]
Thus, plasma was generated in the plasma processing chamber. At this time, the oxygen gas introduced through the plasma processing gas supply port is excited and decomposed in the plasma processing chamber to become active species such as oxygen atoms, transported in the direction of the lens, reacts with the monosilane gas, and the silicon oxide film Was formed on the lens with a thickness of 86 nm. After film formation, the film formation speed and reflection characteristics were evaluated.
[0196]
The film formation rate and uniformity of the obtained silicon nitride film and silicon oxide film are as good as 330 nm / min ± 2.4% and 350 nm / min ± 2.6%, respectively, and the film quality is also a reflectance around 500 nm is 0. It was confirmed that the optical properties were very good at 2%.
[0197]
(Example 5)
Using the plasma processing apparatus having the microwave supply device shown in FIG. 20, a silicon oxide film for semiconductor element interlayer insulation was formed.
As the object to be processed, a P-type single crystal silicon substrate (plane orientation <100>, resistivity 10 Ωcm) having an Al pattern (line and space 0.5 μm) formed on the top was used.
[0198]
First, after the silicon substrate is placed on the support base 2, the plasma processing chamber is evacuated through an exhaust system to obtain 1.33 × 10 6.^-FiveThe pressure was reduced to a value of Pa.
[0199]
Subsequently, the heater was energized, the silicon substrate was heated to 300 ° C., and the substrate was kept at this temperature. Oxygen gas was introduced into the treatment chamber through the plasma treatment gas supply port 7 at a flow rate of 500 sccm and monosilane gas at a flow rate of 200 sccm.
[0200]
Next, a conductance valve 28 provided between the plasma processing chamber and the exhaust pump 18 was adjusted to maintain the plasma processing chamber at 4.0 Pa.
[0201]
Next, 300 W of electric power is applied to the support 2 through the high frequency applying means 22 of 13.56 MHz, and 2.0 kW of electric power is plasma-treated from the 2.45 GHz microwave power source through the endless annular waveguide. Supplied to the room.
[0202]
Thus, plasma was generated in the plasma processing chamber. The oxygen gas introduced through the plasma processing gas supply port 7 is excited and decomposed in the plasma processing chamber to become active species, transported in the direction of the silicon substrate, reacts with the monosilane gas, and the silicon oxide film becomes 0 on the silicon substrate. It was formed with a thickness of 8 μm. At this time, the ion species is accelerated by the RF bias and incident on the substrate, and the film on the pattern is shaved to improve the flatness. After the treatment, the film forming speed, uniformity, withstand voltage, and step coverage were evaluated. The step coverage was evaluated by observing a cross section of the silicon oxide film formed on the Al wiring pattern with a scanning electron microscope (SEM) and observing voids.
[0203]
The film formation rate and uniformity of the obtained silicon oxide film are as good as 250 nm / min ± 2.7%, and the film quality is also confirmed to be a good quality film with a dielectric breakdown voltage of 8.5 MV / cm and void-free. It was.
[0204]
(Example 6)
Using the plasma processing apparatus having the microwave supply device shown in FIG.₂The film was etched.
As an object to be processed, an interlayer SiO having a thickness of 1 μm on an Al pattern (line and space 0.18 μm) is used.₂A P-type single crystal silicon substrate (plane orientation <100>, resistivity 10 Ωcm) on which a film was formed was used.
[0205]
First, after a silicon substrate is placed on the support base 2, the processing chamber is evacuated through an exhaust system to obtain 1.33 × 10 6.^-FiveThe pressure was reduced to a value of Pa. C through the plasma processing gas supply port 7_FourF₈Was introduced into the plasma processing chamber at a flow rate of 100 sccm.
[0206]
Next, a conductance valve 28 provided between the plasma processing chamber and the exhaust pump 18 was adjusted to maintain the plasma processing chamber at a pressure of 1.33 Pa.
[0207]
Next, 300 W of electric power is applied to the support 2 through the high frequency applying means 22 of 13.56 MHz, and 2.0 kW of electric power is plasma-treated from the 2.45 GHz microwave power source through the endless annular waveguide. Supplied to the room.
[0208]
Thus, plasma was generated in the plasma processing chamber. C introduced through the plasma processing gas supply port 7_FourF₈The gas is excited and decomposed in the plasma processing chamber to become active species, transported in the direction of the silicon substrate, and the interlayer SiO by ions accelerated by self-bias.₂The film was etched.
[0209]
The substrate temperature rose only to 80 ° C. by the cooler 114 as the temperature adjusting means. After the etching, the etching rate, the selection ratio, and the etching shape were evaluated. The etched shape was evaluated by observing a cross section of the etched silicon oxide film with a scanning electron microscope (SEM).
[0210]
It was confirmed that the etching rate and uniformity and the selectivity ratio to PR were 560 nm / min ± 3.2% and 15 were good, the etching shape was almost vertical, and the microloading effect was small.
[0211]
(Example 7)
Using the microwave plasma processing apparatus shown in FIG. 20, the polyaryl ether (PAE) film for insulating a semiconductor element interlayer as a low dielectric constant insulator was etched.
As an object to be processed W, a 0.18 μm thick SiOE as a hard mask on a 0.6 μm thick PAE film.₂A P-type single crystal silicon substrate (plane orientation <100>, resistivity 10 Ωcm) having a film pattern formed to a thickness of 0.3 μm was used.
[0212]
First, a silicon substrate is placed on the support base 2, and the substrate temperature is cooled to −10 ° C. by a cooler 114 as temperature adjusting means, and then the plasma processing chamber is evacuated through an exhaust system to obtain 1.33 × 10 6.^-FiveThe pressure was reduced to a value of Pa. N through process gas supply port 7₂Was introduced into the plasma processing chamber at a flow rate of 200 sccm.
[0213]
Next, a conductance valve 28 provided between the plasma processing chamber and the exhaust pump 18 was adjusted to maintain the plasma processing chamber at a pressure of 1.33 Pa.
[0214]
Next, 300 W of power is applied to the support 2 via the 1 MHz high frequency applying means 22 and 2.0 kW of power is supplied from the 2.45 GHz microwave power source to the plasma processing chamber via the endless annular waveguide. Supplied.
[0215]
Thus, plasma was generated in the plasma processing chamber. N introduced through the processing gas supply port 7₂The gas was excited and decomposed in the plasma processing chamber to become active species, transported in the direction of the silicon substrate, and the PAE film was etched by ions accelerated by self-bias.
[0216]
After the etching, the etching rate, the selection ratio, and the etching shape were evaluated. The etched shape was evaluated by observing a cross section of the etched silicon oxide film with a scanning electron microscope (SEM).
[0217]
Etching rate and uniformity versus SiO₂It was confirmed that the selectivity was as good as 660 nm / min ± 3.7%, 10, the etching shape was almost vertical, and the microloading effect was small.
[0218]
【The invention's effect】
According to the present invention, even when processing at low pressure and low power, plasma capable of stably generating high-density and low electron temperature plasma so that high-quality processing can be performed at high speed, uniformly and stably. A processing apparatus and a plasma processing method are realized.
[0219]
According to the present invention, since the microwave radiation characteristic can be controlled more precisely, it is possible to improve the controllability of processing in the radial direction and the circumferential direction of the object to be processed or directions equivalent thereto.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view showing a plasma processing apparatus according to the present invention.
FIG. 2 is a plan view showing an example of a slotted flat plate used in the present invention.
FIG. 3 is a cross-sectional view showing another plasma processing apparatus according to the present invention.
FIG. 4 is a plan view showing another example of a slotted flat plate used in the present invention.
FIG. 5 is a schematic cross-sectional view of a microwave plasma processing apparatus using an annular waveguide according to the present invention.
FIG. 6 is a top view of a flat plate with slots.
FIG. 7 is a schematic cross-sectional view of a microwave plasma processing apparatus using a tangentially introduced annular waveguide according to the present invention.
FIG. 8 is a schematic cross-sectional view of another microwave plasma processing apparatus according to the present invention.
FIG. 9 is a schematic cross-sectional view of another microwave plasma processing apparatus according to the present invention.
FIG. 10 is a diagram illustrating an example of a plasma processing method.
FIG. 11 is a diagram showing another example of a plasma processing method.
FIG. 12 is a diagram showing a configuration of a plasma processing apparatus.
FIG. 13 is a cross-sectional view of a microwave supply device.
FIG. 14 is a cross-sectional view of a waveguide.
FIG. 15 is a diagram showing a state of microwave radiation.
FIG. 16 is a schematic diagram showing a state of microwave propagation in a plasma processing apparatus according to another embodiment of the present invention, a microwave supply used in the present invention, and a microwave supply used in the present invention.
FIG. 17 is a schematic diagram showing the arrangement of slots.
FIG. 18 is a schematic view of a microwave feeder used in the present invention.
FIG. 19 is a schematic view of a microwave feeder used in the present invention.
FIG. 20 is a schematic diagram of a microwave supply device used in the present invention.
[Explanation of symbols]
1 Vacuum container
2 Object holding means
3 Microwave feeder
4 Dielectric window
5 Waveguide
6 Microwave power supply
7 Gas supply path
8 Exhaust passage
9 Plasma generation space
33 slots

Claims (23)

A plasma processing apparatus comprising: a container; a gas supply port for supplying a processing gas into the container; and a microwave supplier for supplying a microwave through the dielectric window into the container. The wave feeder has an annular waveguide having a plurality of slots provided at predetermined intervals on a surface in contact with the dielectric window, and n ₁ is the number of antinodes of the surface standing wave generated between the slots. , the wavelength of the surface wave lambda _5, a n _g as the magnification of one round length l _g of the annular waveguide for road within the wavelength lambda _g, radius r _{e is, r e = n 1 λ 5} / {2tan (π / ( _{2n g))} {1 +} cos (π / n g)}
A plasma processing apparatus, wherein the center of the slot is present on the circumference. The plasma processing apparatus according to claim 1, wherein the value of _ng is in the range of 2 to 5. The plasma processing apparatus according to claim 1, wherein an angular interval of the slots is π / _ng . 2. The plasma processing apparatus according to claim 1, wherein the number n ₁ of antinodes of the surface standing wave generated between the slots is 3, 5, or 7.   The plasma processing apparatus according to claim 1, wherein the dielectric window is mainly composed of aluminum nitride. A step of placing the object to be processed in a container having a dielectric window capable of transmitting microwaves, a step of exhausting the inside of the container, a step of introducing a processing gas into the container, and a contact with the dielectric window A plurality of slots provided in the surface at predetermined intervals, n ₁ is the number of antinodes of the surface standing wave generated between the slots, λ ₅ is the wavelength of the surface wave, and _ng is the path as the magnification of the round length l _g of the annular waveguide with the inner wavelength lambda _g, radius r _{e is, r e = n 1 λ 5} / {2tan (π / (2n g))} {1 + cos (π / n g)}
Using the annular waveguide configured so that the center of the slot exists on the circumference of the plasma, and generating a plasma by supplying microwaves from the annular waveguide into the container. A plasma processing method characterized by the above.   The plasma processing method according to claim 6, wherein a film is formed on the object to be processed by a chemical vapor deposition method.   The plasma processing method according to claim 6, wherein an etching process is performed on the object to be processed.   The plasma processing method according to claim 6, wherein an ashing process is performed on the object to be processed.   The plasma processing method according to claim 6, wherein a doping process is performed on the object to be processed. In a plasma processing apparatus that has a container that can be evacuated inside and a gas supply port that supplies a processing gas into the container, and that performs plasma processing on an object to be processed disposed in the container, Means for supplying microwave energy for generating a plasma of gas, the means for supplying microwave energy is an endless type having a plurality of slots provided at predetermined intervals on the surface of the dielectric window. Having an annular waveguide, n ₁ is the number of antinodes of the surface standing wave generated between the slots, λ ₅ is the wavelength of the surface wave, _ng is the circumference of the annular waveguide with respect to the intra-path wavelength λ _g as the magnification of l _g, radius r _{e is, r e = n 1 λ 5} / {2tan (π / (2n g))} {1 + cos (π / n g)}
The plasma is characterized in that the centers of the plurality of slots are arranged so as to be offset from the center of the annular waveguide in a direction along the plane so that the centers of the slots exist on a circumference of Processing equipment. The plasma processing apparatus according to claim 11, wherein the value of _ng is in the range of 2-5. The plasma processing apparatus of claim 11, wherein an angular interval of the slots is π / _ng . The plasma processing apparatus according to claim 11, wherein the number n ₁ of antinodes of the surface standing wave generated between the slots is 3, 5, or 7.   The plasma processing apparatus according to claim 11, wherein a main component of the dielectric window is aluminum nitride.   The plasma processing apparatus according to claim 11, wherein the gas supply port is provided on a side wall of the container.   The plasma processing apparatus according to claim 11, wherein the gas supply port is provided closer to a surface on which the plurality of slots are provided than the object to be processed.   The plasma processing apparatus according to claim 11, wherein the processing gas is discharged from the gas supply port toward a surface provided with the plurality of slots. The plasma processing apparatus according to claim 11, wherein the container is provided with an exhaust pump capable of reducing the pressure in the container to 1.34 × 10 ³ Pa or less.   A plasma processing method for plasma processing a target object, wherein the target object is plasma processed using the plasma processing apparatus according to claim 11.   21. The plasma processing method according to claim 20, wherein the plasma processing method is at least one of ashing, etching, cleaning, CVD, plasma polymerization, doping, oxidation, and nitridation.   A method for manufacturing a structure, comprising the step of plasma processing an object to be processed using the plasma processing apparatus according to claim 1.   A method of manufacturing a structure, comprising the step of plasma processing the object to be processed using the plasma processing apparatus according to claim 11.

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