JP2004071755A

JP2004071755A - Plasma treatment method and apparatus thereof

Info

Publication number: JP2004071755A
Application number: JP2002227376A
Authority: JP
Inventors: Masanori Sakamoto; 坂本　正紀; Seiji Matsumoto; 松元　省二; Shiyunsuke Hisakure; 久呉　俊介; Hirotoshi Nakada; 中田　弘利
Original assignee: Matsushita Electric Industrial Co Ltd
Current assignee: Panasonic Holdings Corp
Priority date: 2002-08-05
Filing date: 2002-08-05
Publication date: 2004-03-04

Abstract

<P>PROBLEM TO BE SOLVED: To reduce the frequency of replacement of a peripheral member which is consumed by ion irradiation of a plasma, and to stabilize the process characteristics. <P>SOLUTION: A plasma treatment apparatus comprises a substrate placing part 5 for placing a substrate 2 to be treated by the plasma generated in a pressure reducible reaction chamber, and a peripheral member 3 which is arranged around the substrate placing part 5 and movable at least in the direction opposite to the direction that the surface of the peripheral member 3 is consumed by the plasma. Consequently, even when the surface of the peripheral member 3 is consumed by the plasma and the relative surface position of the peripheral member 3 is shifted, the surface of the member 3 can be easily returned to its original position. Hence, it is possible to restrain the fluctuating condition of the plasma, and to stabilize the process characteristics. It is also possible to extend the replacement interval in replacing the peripheral member 3 while opening the reaction chamber, and to reduce cost for the maintenance. <P>COPYRIGHT: (C)2004,JPO

Description

【０００１】
【発明の属する技術分野】
この発明は、半導体集積回路などをプラズマを用いて素子パターン形成などを行うプラズマ処理方法およびプラズマ処理装置に関するものである。
【０００２】
【従来の技術】
真空または減圧することができる反応室にガスを導入し、そのガスをプラズマ化させて処理を行うプラズマ加工（ドライエッチング）技術は、現在の高集積化が進む半導体デバイスを微細加工する上で必須の技術である。図７に従来のドライエッチング装置の反応室内部の主要構造を示す。同図において、半導体基板２がガスプラズマを発生させるための高周波電圧を印加する下部電極５上に設置され、下部電極５の周囲には絶縁材料でできたリング状の周辺部材３が台座６上に設けられている。この周辺部材３はいわゆるフォーカスリングを含むものである。下部電極５は、セラミックやアルマイト表面被覆の金属からなることが多い。また、下部電極周辺部材３は、ＳｉＣ、Ｓｉ、ＳｉＯ_２、アルミナなどからなり、どの材料を用いるかは、半導体基板上に形成されたエッチング膜材料によって異なっている。
【０００３】
このような構造において、ドライエッチング時には半導体基板２に近い空間でプラズマ１が発生し、半導体基板２上の被エッチング膜がエッチングされるとともに、当然半導体基板２周囲の下部電極周辺部材３の表面もプラズマ１にさらされ部材の消耗が進むことになるのである。この現象はプラズマを用いる限り現状では回避することが困難である。
【０００４】
【発明が解決しようとする課題】
以上のように、ドライエッチング装置において周辺部材３の消耗が進むと、図８に示すように半導体基板２の高さに対して、周辺部材３表面の高さが徐々に下がり、消耗空間７が大きくなってゆくが、この現象は半導体基板エッチング時、プラズマ発生領域の広さが変化する、エッチングの均一性が変化する、エッチング速度が変動するなど、すなわち反応室内のプラズマ状態が変動する。そしてこれにより、ドライエッチング条件を初期に一定の条件に設定しても時間とともにわずかずつシフトし、プロセス特性の安定化が損なわれるという問題がある。
【０００５】
消耗した周辺部材３を新品に交換することにより、エッチング特性の安定性をある程度の範囲内で保つことが可能ではあるが、周辺部材３の消耗に対応して、厳密には刻々とプロセス特性は変動し、半導体装置の加工不良の要因になる。また周辺部材３を交換するという保守作業を高頻度で行うと、反応室を大気中に開放しなければならないので装置の稼働率低下へつながり、設備保守費用が増大するという欠点がある。
【０００６】
したがって、この発明の目的は、上記課題を解決することで、プラズマのイオン照射により消耗した周辺部材の交換頻度を減らし、プロセス特性の安定化を図ることができるプラズマ処理方法およびプラズマ処理装置を提供することである。
【０００７】
【課題を解決するための手段】
上記目的を達成するためにこの発明の請求項１記載のプラズマ処理方法は、基板設置部に基板を設置して前記基板をプラズマ処理する際、プラズマにより前記基板設置部の周囲に設けた周辺部材の表面が所定量消耗した後、前記周辺部材の表面が消耗した方向と反対方向に、消耗量に相当する距離だけ前記周辺部材を移動させる工程と、前記周辺部材を移動後、前記基板のプラズマ処理を続ける工程とを含む。
【０００８】
このように、プラズマにより基板設置部の周囲に設けた周辺部材の表面が所定量消耗した後、周辺部材の表面が消耗した方向と反対方向に、消耗量に相当する距離だけ周辺部材を移動させる工程と、周辺部材を移動後、基板のプラズマ処理を続ける工程とを含むので、周辺部材の表面がプラズマにより消耗して基板との相対的位置が変動したとしても、表面の位置を元に戻すことができる。したがって、プラズマ発生領域の広さが一定となることでプラズマ状態変動を抑制しプロセス特性を安定化させられる。また、周辺部材の交換周期を延長させ、保守のコスト低減を可能にする。
【０００９】
請求項２記載のプラズマ処理方法は、基板設置部に基板を設置して前記基板をプラズマ処理する際、プラズマにより前記基板設置部の周囲に設けた周辺部材の表面が所定量消耗したことを検出する工程と、所定量消耗したことを検出した後、前記周辺部材の表面が消耗した方向と反対方向に、消耗量に相当する距離だけ前記周辺部材を移動させる工程と、前記周辺部材を移動後、前記基板のプラズマ処理を続ける工程とを含む。
【００１０】
このように、プラズマにより基板設置部の周囲に設けた周辺部材の表面が所定量消耗したことを検出する工程と、所定量消耗したことを検出した後、周辺部材の表面が消耗した方向と反対方向に、消耗量に相当する距離だけ周辺部材を移動させる工程と、周辺部材を移動後、基板のプラズマ処理を続ける工程とを含むので、周辺部材の表面がプラズマにより消耗して基板との相対的位置が変動したとしても、所定量の消耗を検出して周辺部材を所定量上昇させることで、表面の位置を元に戻すことができる。したがって、プラズマ発生領域の広さが一定となることでプラズマ状態変動を抑制しプロセス特性を安定化させられる。また、周辺部材の交換周期を延長させ、保守のコスト低減を可能にする。
【００１１】
請求項３記載のプラズマ処理装置は、減圧可能な反応室内に発生させたプラズマにより処理する基板を設置する基板設置部と、前記基板設置部の周囲に設けられた周辺部材とを備え、前記周辺部材は、前記プラズマにより前記周辺部材の表面が消耗する方向と反対方向に少なくとも可動である。
【００１２】
このように、周辺部材は、プラズマにより周辺部材の表面が消耗する方向と反対方向に少なくとも可動であるので、周辺部材の表面がプラズマにより消耗して基板との相対的位置が変動したとしても、表面の位置を元に戻すことが容易である。したがって、プラズマ発生領域の広さが一定となることでプラズマ状態変動を抑制しプロセス特性を安定化させられる。それとともに反応室を大気開放して交換する際の交換周期を延長させ、保守のコスト低減を可能にする。
【００１３】
請求項４記載のプラズマ処理装置は、減圧可能な反応室内に発生させたプラズマにより処理する基板を設置する基板設置部と、前記基板設置部の周囲に設けられた周辺部材と、前記プラズマにより前記周辺部材の表面が所定量消耗したことを検出する検出手段とを備え、前記検出手段の検出結果に基づいて、前記周辺部材は、その表面が消耗する方向と反対方向に少なくとも可動である。
【００１４】
このように、プラズマにより周辺部材の表面が所定量消耗したことを検出する検出手段の検出結果に基づいて、周辺部材は、その表面が消耗する方向と反対方向に少なくとも可動であるので、周辺部材の表面がプラズマにより消耗して基板との相対的位置が変動したとしても、検出手段で所定量の消耗を検出して周辺部材を所定量上昇させることで、表面の位置を元に戻すことができる。したがって、プラズマ発生領域の広さが一定となることでプラズマ状態変動を抑制しプロセス特性を安定化させられる。それとともに反応室を大気開放して交換する際の交換周期を延長させ、保守のコスト低減を可能にする。
【００１５】
請求項５記載のプラズマ処理装置は、減圧可能な反応室内に発生させたプラズマにより処理する基板を設置する基板設置部と、前記基板設置部の周囲に設けられた周辺部材と、前記プラズマにより前記周辺部材の表面が所定量消耗したことを検出する検出手段と、前記検出手段からの検出信号を受けて前記周辺部材の上下移動可不可判断を行いこの判断結果に基づいて移動信号を発信する演算部と、前記移動信号に基づいて前記周辺部材をその表面が消耗する方向と反対方向に所定距離移動させる移動制御部とを備えた。
【００１６】
このように、プラズマにより周辺部材の表面が所定量消耗したことを検出する検出手段と、検出手段からの検出信号を受けて周辺部材の上下移動可不可判断を行いこの判断結果に基づいて移動信号を発信する演算部と、移動信号に基づいて周辺部材をその表面が消耗する方向と反対方向に所定距離移動させる移動制御部とを備えたので、周辺部材の表面がプラズマにより消耗して基板との相対的位置が変動したとしても、検出手段で所定量の消耗を検出して周辺部材を所定量上昇させることで、表面の位置を元に戻すことができる。この際、検出手段からの検出信号が演算部に入力され、上下移動可不可判断のための自動計算を実施し、上下移動可能であった場合に、移動制御部に対して移動信号を発信し、表面が消耗した所定距離だけ上昇させる。したがって、プラズマ発生領域の広さが一定となることでプラズマ状態変動を抑制しプロセス特性を安定化させられる。それとともに反応室を大気開放して交換する際の交換周期を延長させ、保守のコスト低減を可能にする。
【００１７】
請求項６記載のプラズマ処理装置は、請求項４または５記載のプラズマ処理装置において、検出手段は、周辺部材を挟んで配置された発光部および受光部からなる。このように、検出手段は、周辺部材を挟んで配置された発光部および受光部からなるので、発光部からの光は最初は周辺部材で遮断された状態にあり受光部で検知されないが、周辺部材の表面が消耗し一定の高さになると光が受光部で検知されることで周辺部材の所定量の消耗を検出できる。
【００１８】
【発明の実施の形態】
この発明の第１の実施の形態を図１および図２に基づいて説明する。図１は、この発明の第１の実施の形態のプラズマ処理装置であるドライエッチング装置を用いたエッチング方法を示す概略断面図である。
【００１９】
図１に示すように、減圧可能な反応室内に発生させたプラズマ１により処理する半導体基板２を設置する基板設置部（下部電極５）と、基板設置部の周囲に設けられた周辺部材３とを備え、周辺部材３は、プラズマ１により周辺部材３の表面が消耗する方向と反対方向に少なくとも可動である。
【００２０】
この場合、図１（ａ）は、本実施の形態のドライエッチング装置において、真空または減圧可能な反応室内部の、半導体基板２が設置された部分であり、装置の初期の状態を示している。半導体基板２が設置され高周波電圧を印加してプラズマ１を発生させる下部電極５の周囲に、絶縁材料からなる下部電極周辺部材３が設けられ、支持体４によって支持されている。そしてこの支持体４は周辺部材３とともに下部電極５に沿って上下に移動可変な構造を有するものである。すなわち、下部電極５の下端に突部５ａが形成され、この突部５ａに嵌合される穴４ａが支持体４に形成されている。図１（ａ）では、周辺部材３が新品の状態であり消耗はない。なお、周辺部材３および下部電極５は従来と同様の材質で形成される。
【００２１】
上記ドライエッチング処理装置において、下部電極５に半導体基板２を設置して半導体基板２をプラズマ処理する際、プラズマ１により下部電極５の周囲に設けた周辺部材３の表面が所定量消耗した後、周辺部材３の表面が消耗した方向と反対方向に、消耗量に相当する距離だけ周辺部材３を移動させる工程と、周辺部材３を移動後、半導体基板２のプラズマ処理を続ける工程とを行う。
【００２２】
すなわち、半導体基板２のドライエッチング処理枚数を増加していくと、この装置においても従来のように周辺部材３の表面がエッチングガスのプラズマ１により、プラズマ中のイオン衝撃を受けて徐々に消耗してゆき、図１（ｂ）のように周辺部材３の表面位置が下がるが、ある一定の量だけ下がったとき、周辺部材３を上方に移動させ、すなわちプラズマ１によって表面が消耗した方向とは反対方向に消耗した距離分だけ移動させ、半導体基板２の高さと周辺部材３の表面高さを一致させる（図１（ｃ））。こうすることによって半導体基板２と周辺部材３との位置関係を初期状態（図１（ａ））に戻す事ができる。したがってドライエッチング中のプラズマ１も初期状態に戻り、安定したエッチングプロセスを長期間維持することができるようになる。
【００２３】
図２は、ドライエッチングプロセスでの半導体基板（ウエハ）処理枚数と下部電極周辺部材厚さとの関係の一例を示すグラフである。図２に示すように、一定の率で部材が消耗することがわかる。従来、例えば下部電極周辺部材の消耗が２ｍｍを越えた時に部材を交換したとすると、交換周期は約３０００枚処理した後となっていた。一方、本発明の場合、初期の周辺部材厚を３０ｍｍ、ドライエッチング装置において最低限必要な部材厚を２０ｍｍとした場合、許容消耗量は１０ｍｍで、部材の交換までに行う半導体基板処理枚数は約１５０００枚となり、交換保守作業周期を５倍にすることが可能となり、部材の交換周期を５倍延命することができる。結果として、エッチング装置稼動率が上昇し、設備保守費用低減が本発明により実現できる。
【００２４】
この発明の第２の実施の形態を図３〜図５に基づいて説明する。図３は、この発明の第２の実施の形態のプラズマ処理装置であるドライエッチング装置を用いたエッチング方法を示す概略断面図である。
【００２５】
図３に示すように、減圧可能な反応室内に発生させたプラズマ１により処理する半導体基板２を設置する基板設置部（下部電極５）と、基板設置部の周囲に設けられた周辺部材３と、プラズマ１により周辺部材３の表面が所定量消耗したことを検出する検出手段８，９とを備え、検出手段８，９の検出結果に基づいて、周辺部材３は、その表面が消耗する方向と反対方向に少なくとも可動である。
【００２６】
この場合、図３（ａ）は、本実施の形態のドライエッチング装置内部構造の初期状態を示すものである。この装置においては、図示していないが反応室内壁に検出手段としてレーザー発光部８とレーザー受光部９が周辺部材３を挟んで水平配置で設けられていることが特徴である。これ以外の構造は図１（ａ）の装置と同様であり、半導体基板２を設置する下部電極５の周囲に上下に移動できる支持体４と、この支持体４に取り付けられた下部電極周辺部材３とを備えているが、周辺部材３の水平表面の高さは半導体基板２の高さより高くなっている。そしてレーザー発光部８からのレーザー光は最初は周辺部材３で遮断された状態にある。
【００２７】
上記ドライエッチング処理装置において、下部電極５に半導体基板２を設置して半導体基板２をプラズマ処理する際、プラズマ１により下部電極５の周囲に設けた周辺部材３の表面が所定量消耗したことを検出する工程と、所定量消耗したことを検出した後、周辺部材３の表面が消耗した方向と反対方向に、消耗量に相当する距離だけ周辺部材３を移動させる工程と、周辺部材３を移動後、半導体基板２のプラズマ処理を続ける工程とを行う。
【００２８】
すなわち、半導体基板２のドライエッチング処理枚数が多くなるにしたがって下部電極周辺部材３の表面は消耗し、図３（ｂ）のようにレーザー受光部９にレーザー光１０が達するようになる支持体４に連動している上下移動可変機構に受光信号が送られ、自動的に下部電極周辺部材３を所定量上昇させる。そのことにより図３（ｃ）のように下部電極周辺部材３の高さを初期状態（図３（ａ））に戻す事ができ、エッチングプラズマの変動が少ない安定したプロセスを行うことができ、部材交換の頻度を減少させ、保守費用低減を図れる。
【００２９】
第１の実施の形態では半導体基板のドライエッチング処理枚数をカウントし、一定の処理枚数に達したころに手動で周辺部材高さを調節する必要が生じていたが、本実施の形態では周辺部材３の消耗を自動的に感知して一定の高さに調節することができる。例えばレーザー光１０が周辺部材表面から０．５ｍｍ下の周辺部材側面に照射されるようにしておけば、図２のデータから約７５０枚基板を処理した後、レーザー光１０がレーザー受光部９で検知され、自動的に高さが調整される。このように高さ調節を自動化すると、周辺部材３の消耗が大きくならないうちにその表面位置を初期状態に戻す事も可能となるのでさらに一層ドライエッチングプロセス条件を安定にできる。
【００３０】
次に図３に示したドライエッチング装置の周辺部材高さ調節制御系とその制御フローについて説明する。図４は図３のドライエッチング装置の高さ制御系の構成を示す概略図であり、図５はその制御手順を示すフロー図である。
【００３１】
図４に示すように、検出手段８，９からの検出信号を受けて周辺部材３の上下移動可不可判断を行いこの判断結果に基づいて移動信号を発信する演算部１３と、移動信号に基づいて周辺部材３をその表面が消耗する方向と反対方向に所定距離移動させる移動制御部１２とを備えている。
【００３２】
この装置の初期状態においては、レーザー光１０が下部電極周辺部材３に遮光されているが、反応室（チャンバー）１１内のプラズマにより表面が消耗することにより図４のようにレーザー受光部９でレーザー光１０を受光する（Ｓ１〜Ｓ３）。
【００３３】
その受光を表す検出信号はレーザー受光部９より装置内ＣＰＵ（演算装置）１３に入力される（Ｓ４）。次にＣＰＵ１３が上下移動可不可判断のための自動計算を実施し（Ｓ５）、可不可（ＮＧまたはＯＫ）それぞれに対しての出力信号を発する（Ｓ６）。
【００３４】
上下移動可能であった場合、周辺部材３の支持体４に連動している上下移動可変機構１２に対して移動信号を発し（Ｓ７）、表面が消耗した所定距離だけ上昇を実施する（Ｓ８）。このことによりレーザー光１０は再び遮光され（Ｓ９）、半導体基板処理が可能となる（Ｓ１）。
【００３５】
また例えば下部電極周辺部材３がその許容厚さ程度まで相当量消耗しており、上下移動不可と判断された場合、ＣＰＵ１３はアラーム表示信号を発し（Ｓ１０）、周辺部材３の交換作業を促すアラームを装置モニター（ＣＲＴ）１４に表示する。こうしてアラーム発生時の半導体基板１枚の処理が終了した後は、次の処理が行われないようにする（Ｓ１１）。そして支持体４を上下移動させる可変機構１２は、図３（ａ）のように新品の周辺部材３が装着されたのと同じ位置に自動的に移動し（Ｓ１２）、交換作業が行える状態になる（Ｓ１３）。
【００３６】
以上説明した第２の実施の形態によるドライエッチング装置に設けられた周辺部材表面位置検出機構は、半導体基板２より下部電極周辺部材３の表面のほうが本来高い位置にあるような装置に対して適用され、図１に示したような、基板２と表面とを実質的に同一高さにしなければならない配置の装置には適用することは難しいものである。これに対しては以下に述べる第３の実施の形態のようにすることで解決できる。
【００３７】
この発明の第３の実施の形態を図６に基づいて説明する。図６は、この発明の第３の実施の形態のプラズマ処理装置であるドライエッチング装置を用いたエッチング方法を示す概略断面図である。
【００３８】
図６に示すように、第２の実施の形態と同様に減圧可能な反応室内に発生させたプラズマ１により処理する半導体基板２を設置する基板設置部（下部電極５）と、基板設置部の周囲に設けられた周辺部材３と、プラズマ１により周辺部材３の表面が所定量消耗したことを検出する検出手段８，９とを備え、検出手段８，９の検出結果に基づいて、周辺部材３は、その表面が消耗する方向と反対方向に少なくとも可動である。
【００３９】
この装置におけるエッチング処理の初期状態は、半導体基板２と周辺部材３の表面とが同じ位置にある。また、検出手段としてレーザー発光部８とレーザー受光部９は図示していないが反応室壁面の適当な場所に固定設置されている。この際、レーザー発光部８は下部電極周辺部材３の端部をレーザー光１０で斜め上から外側に向けて照射し、それを受けることができるようにレーザー受光部９は斜め下にある。
【００４０】
周辺部材３の交換直後は図６（ａ）のようにレーザー光１０が周辺部材端部で遮光されるが、半導体基板２のエッチング枚数が増加し、プラズマ１にさらされる時間がある程度長くなると表面の消耗によって位置が下がり、図６（ｂ）のようにレーザー光１０がレーザー受光部９で受光されるようになる。そうすると図６（ｃ）のように支持体４を上方向に移動し周辺部材３の表面を初期の位置に戻す。このようにして再びレーザー光１０は遮光され、エッチングプラズマも初期に戻って、周辺部材３を交換することなく安定なプロセスを維持することができる。
【００４１】
以上の例ではレーザー発光部８が上部に位置する場合を述べたがレーザー発光部８、受光部９の位置を入れ替え、斜め下から周辺部材３の端部をレーザー光照射するようにしてもよい。その他の構成効果は、第２の実施の形態と同様である。
【００４２】
【発明の効果】
この発明の請求項１記載のプラズマ処理方法によれば、プラズマにより基板設置部の周囲に設けた周辺部材の表面が所定量消耗した後、周辺部材の表面が消耗した方向と反対方向に、消耗量に相当する距離だけ周辺部材を移動させる工程と、周辺部材を移動後、基板のプラズマ処理を続ける工程とを含むので、周辺部材の表面がプラズマにより消耗して基板との相対的位置が変動したとしても、表面の位置を元に戻すことができる。したがって、プラズマ発生領域の広さが一定となることでプラズマ状態変動を抑制しプロセス特性を安定化させられ、ドライエッチングなどプラズマ処理を安定に行うことができる。また、周辺部材の交換周期を延長させ、保守のコスト低減を可能にする。
【００４３】
この発明の請求項２記載のプラズマ処理方法によれば、プラズマにより基板設置部の周囲に設けた周辺部材の表面が所定量消耗したことを検出する工程と、所定量消耗したことを検出した後、周辺部材の表面が消耗した方向と反対方向に、消耗量に相当する距離だけ周辺部材を移動させる工程と、周辺部材を移動後、基板のプラズマ処理を続ける工程とを含むので、周辺部材の表面がプラズマにより消耗して基板との相対的位置が変動したとしても、所定量の消耗を検出して周辺部材を所定量上昇させることで、表面の位置を元に戻すことができる。したがって、プラズマ発生領域の広さが一定となることでプラズマ状態変動を抑制しプロセス特性を安定化させられ、ドライエッチングなどプラズマ処理を安定に行うことができる。また、周辺部材の交換周期を延長させ、保守のコスト低減を可能にする。
【００４４】
この発明の請求項３記載のプラズマ処理装置によれば、周辺部材は、プラズマにより周辺部材の表面が消耗する方向と反対方向に少なくとも可動であるので、周辺部材の表面がプラズマにより消耗して基板との相対的位置が変動したとしても、表面の位置を元に戻すことが容易である。したがって、プラズマ発生領域の広さが一定となることでプラズマ状態変動を抑制しプロセス特性を安定化させられる。また、真空あるいは減圧状態の反応室を大気解放して周辺部材を交換する保守作業周期の延長を行うことができ、したがって設備保守コスト、生産コスト低減を行うことができる。
【００４５】
この発明の請求項４記載のプラズマ処理装置によれば、プラズマにより周辺部材の表面が所定量消耗したことを検出する検出手段の検出結果に基づいて、周辺部材は、その表面が消耗する方向と反対方向に少なくとも可動であるので、周辺部材の表面がプラズマにより消耗して基板との相対的位置が変動したとしても、検出手段で所定量の消耗を検出して周辺部材を所定量上昇させることで、表面の位置を元に戻すことができる。したがって、プラズマ発生領域の広さが一定となることでプラズマ状態変動を抑制しプロセス特性を安定化させられる。また、真空あるいは減圧状態の反応室を大気解放して周辺部材を交換する保守作業周期の延長を行うことができ、したがって設備保守コスト、生産コスト低減を行うことができる。
【００４６】
この発明の請求項５記載のプラズマ処理装置によれば、プラズマにより周辺部材の表面が所定量消耗したことを検出する検出手段と、検出手段からの検出信号を受けて周辺部材の上下移動可不可判断を行いこの判断結果に基づいて移動信号を発信する演算部と、移動信号に基づいて周辺部材をその表面が消耗する方向と反対方向に所定距離移動させる移動制御部とを備えたので、周辺部材の表面がプラズマにより消耗して基板との相対的位置が変動したとしても、検出手段で所定量の消耗を検出して周辺部材を所定量上昇させることで、表面の位置を元に戻すことができる。この際、検出手段からの検出信号が演算部に入力され、上下移動可不可判断のための自動計算を実施し、上下移動可能であった場合に、移動制御部に対して移動信号を発信し、表面が消耗した所定距離だけ上昇させる。したがって、プラズマ発生領域の広さが一定となることでプラズマ状態変動を抑制しプロセス特性を安定化させられる。また、真空あるいは減圧状態の反応室を大気解放して周辺部材を交換する保守作業周期の延長を行うことができ、したがって設備保守コスト、生産コスト低減を行うことができる。
【００４７】
請求項６では、検出手段は、周辺部材を挟んで配置された発光部および受光部からなるので、発光部からの光は最初は周辺部材で遮断された状態にあり受光部で検知されないが、周辺部材の表面が消耗し一定の高さになると光が受光部で検知されることで周辺部材の所定量の消耗を検出できる。
【図面の簡単な説明】
【図１】この発明の第１の実施の形態によるドライエッチング装置主要部の動作を示す概略断面図である。
【図２】半導体基板のプラズマ処理枚数と下部電極周辺部材のプラズマ消耗による厚さ変化の関係図である。
【図３】この発明の第２の実施の形態によるドライエッチング装置主要部の動作を示す概略断面図である。
【図４】この発明の第２の実施の形態によるドライエッチング装置における下部電極周辺部材上下移動制御系の概略を示すブロック図である。
【図５】この発明の第２の実施の形態によるドライエッチング装置における下部電極周辺部材上下移動制御系のフロー図である。
【図６】この発明の第３の実施の形態によるドライエッチング装置主要部の動作を示す概略断面図である。
【図７】従来のドライエッチング装置主要部構成を示す概略断面図である。
【図８】従来のドライエッチング装置において下部電極周辺部材の消耗を示した説明図である。
【符号の説明】
１　プラズマ
２　半導体基板
３　周辺部材
４　支持体
５　下部電極（基板設置部）
６　周辺部材台座
７　プラズマによる消耗部分
８　レーザー発光部
９　レーザー受光部
１０　レーザー光
１１　反応室
１２　上下移動制御部
１３　ＣＰＵ
１４　ＣＲＴ[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a plasma processing method and a plasma processing apparatus for forming an element pattern on a semiconductor integrated circuit or the like using plasma.
[0002]
[Prior art]
Plasma processing (dry etching) technology, in which a gas is introduced into a reaction chamber that can be evacuated or decompressed, and the gas is turned into plasma for processing, is indispensable for microfabrication of today's highly integrated semiconductor devices. Technology. FIG. 7 shows a main structure inside a reaction chamber of a conventional dry etching apparatus. In the figure, a semiconductor substrate 2 is placed on a lower electrode 5 for applying a high-frequency voltage for generating gas plasma, and a ring-shaped peripheral member 3 made of an insulating material is placed on a pedestal 6 around the lower electrode 5. It is provided in. The peripheral member 3 includes a so-called focus ring. The lower electrode 5 is often made of ceramic or alumite surface-coated metal. The lower electrode peripheral member 3 is made of SiC, Si, SiO ₂ , Alumina, etc., which material to use depends on the material of the etching film formed on the semiconductor substrate.
[0003]
In such a structure, at the time of dry etching, plasma 1 is generated in a space close to the semiconductor substrate 2, the film to be etched on the semiconductor substrate 2 is etched, and the surface of the lower electrode peripheral member 3 around the semiconductor substrate 2 is naturally The members are exposed to the plasma 1 and the members are consumed. This phenomenon is currently difficult to avoid as long as plasma is used.
[0004]
[Problems to be solved by the invention]
As described above, when the wear of the peripheral member 3 proceeds in the dry etching apparatus, the height of the surface of the peripheral member 3 gradually decreases with respect to the height of the semiconductor substrate 2 as shown in FIG. This phenomenon is caused by the fact that, when etching the semiconductor substrate, the plasma generation area changes, the etching uniformity changes, the etching rate fluctuates, and the like, that is, the plasma state in the reaction chamber fluctuates. As a result, even if the dry etching condition is initially set to a constant condition, the condition slightly shifts with time, and there is a problem that the stabilization of the process characteristics is impaired.
[0005]
By replacing the worn out peripheral member 3 with a new one, it is possible to maintain the stability of the etching characteristics within a certain range. Fluctuates and becomes a factor of processing failure of the semiconductor device. Further, if the maintenance work of replacing the peripheral member 3 is performed at a high frequency, the reaction chamber must be opened to the atmosphere, which leads to a decrease in the operation rate of the apparatus, and there is a disadvantage that the equipment maintenance cost increases.
[0006]
Therefore, an object of the present invention is to provide a plasma processing method and a plasma processing apparatus which can solve the above-mentioned problems, reduce the frequency of replacement of peripheral members consumed by plasma ion irradiation, and stabilize process characteristics. It is to be.
[0007]
[Means for Solving the Problems]
In order to achieve the above object, a plasma processing method according to claim 1 of the present invention is characterized in that, when a substrate is installed in a substrate installation section and the substrate is subjected to plasma processing, a peripheral member provided around the substrate installation section by plasma Moving the peripheral member by a distance corresponding to the amount of consumption in a direction opposite to the direction in which the surface of the peripheral member has been consumed after the surface of the substrate has been consumed by a predetermined amount; Continuing the process.
[0008]
As described above, after the surface of the peripheral member provided around the substrate installation portion is consumed by a predetermined amount due to the plasma, the peripheral member is moved in a direction opposite to the direction in which the surface of the peripheral member is consumed by a distance corresponding to the consumption amount. Since the method includes a step and a step of continuing the plasma processing of the substrate after moving the peripheral member, even if the surface of the peripheral member is consumed by plasma and the relative position with respect to the substrate is changed, the position of the surface is returned to the original position. be able to. Therefore, the variation in the plasma state is suppressed by stabilizing the width of the plasma generation region, and the process characteristics can be stabilized. Further, the replacement cycle of the peripheral members is extended, and the cost for maintenance can be reduced.
[0009]
3. The plasma processing method according to claim 2, wherein when the substrate is set on the substrate setting portion and the substrate is subjected to plasma processing, it is detected that a predetermined amount of the surface of a peripheral member provided around the substrate setting portion has been consumed by plasma. And after detecting that the peripheral member has been consumed by a predetermined amount, moving the peripheral member by a distance corresponding to the consumed amount in a direction opposite to the direction in which the surface of the peripheral member has been consumed, and after moving the peripheral member. Continuing the plasma processing of the substrate.
[0010]
As described above, the step of detecting that the surface of the peripheral member provided around the substrate installation portion has been consumed by the plasma by a predetermined amount, and the step of detecting that the surface of the peripheral member has been exhausted after detecting that the predetermined amount has been consumed. The method includes a step of moving the peripheral member by a distance corresponding to the amount of consumption in the direction, and a step of continuing the plasma processing of the substrate after moving the peripheral member. Even if the target position changes, the surface position can be returned to the original position by detecting a predetermined amount of wear and raising the peripheral members by a predetermined amount. Therefore, the variation in the plasma state is suppressed by stabilizing the width of the plasma generation region, and the process characteristics can be stabilized. Further, the replacement cycle of the peripheral members is extended, and the cost for maintenance can be reduced.
[0011]
The plasma processing apparatus according to claim 3, further comprising: a substrate installation unit for installing a substrate to be processed by plasma generated in a reaction chamber that can be decompressed; and a peripheral member provided around the substrate installation unit; The member is movable at least in a direction opposite to a direction in which the surface of the peripheral member is consumed by the plasma.
[0012]
In this way, since the peripheral member is at least movable in the direction opposite to the direction in which the surface of the peripheral member is consumed by the plasma, even if the surface of the peripheral member is consumed by the plasma and the relative position to the substrate changes, It is easy to restore the position of the surface. Therefore, the variation in the plasma state is suppressed by stabilizing the width of the plasma generation region, and the process characteristics can be stabilized. At the same time, the replacement cycle when exchanging the reaction chamber by opening the reaction chamber to the atmosphere is extended, so that the maintenance cost can be reduced.
[0013]
The plasma processing apparatus according to claim 4, wherein a substrate installation section for installing a substrate to be processed by plasma generated in a reaction chamber that can be decompressed, a peripheral member provided around the substrate installation section, and the plasma Detecting means for detecting that the surface of the peripheral member has been consumed by a predetermined amount, and based on a detection result of the detecting means, the peripheral member is at least movable in a direction opposite to a direction in which the surface is consumed.
[0014]
As described above, the peripheral member is at least movable in the direction opposite to the direction in which the surface is consumed, based on the detection result of the detection unit that detects that the surface of the peripheral member has been consumed by the predetermined amount due to the plasma. Even if the surface of the substrate is depleted by plasma and its relative position to the substrate fluctuates, it is possible to return the surface position to the original position by detecting a predetermined amount of depletion by the detecting means and raising the peripheral member by a predetermined amount. it can. Therefore, the variation in the plasma state is suppressed by stabilizing the width of the plasma generation region, and the process characteristics can be stabilized. At the same time, the replacement cycle when exchanging the reaction chamber by opening the reaction chamber to the atmosphere is extended, so that the maintenance cost can be reduced.
[0015]
The plasma processing apparatus according to claim 5, wherein a substrate installation section for installing a substrate to be processed by plasma generated in a reaction chamber that can be decompressed, a peripheral member provided around the substrate installation section, and the plasma A detecting means for detecting that the surface of the peripheral member has been consumed by a predetermined amount; and an operation of receiving a detection signal from the detecting means, determining whether or not the peripheral member can be moved up and down, and transmitting a movement signal based on the determination result. And a movement control unit configured to move the peripheral member a predetermined distance in a direction opposite to a direction in which the surface is consumed based on the movement signal.
[0016]
As described above, the detection means for detecting that the surface of the peripheral member has been consumed by a predetermined amount due to the plasma, and the detection of the detection signal from the detection means determines whether or not the vertical movement of the peripheral member is possible. And a movement controller for moving the peripheral member a predetermined distance in a direction opposite to the direction in which the surface is consumed based on the movement signal, so that the surface of the peripheral member is consumed by plasma and Even if the relative position of the surface changes, the surface position can be returned to the original position by detecting the consumption of a predetermined amount by the detecting means and raising the peripheral member by the predetermined amount. At this time, the detection signal from the detection means is input to the arithmetic unit, and an automatic calculation for determining whether or not the vertical movement is possible is performed. If the vertical movement is possible, a movement signal is transmitted to the movement control unit. Then, the surface is raised by a predetermined distance which has been consumed. Therefore, the variation in the plasma state is suppressed by stabilizing the width of the plasma generation region, and the process characteristics can be stabilized. At the same time, the replacement cycle when exchanging the reaction chamber by opening the reaction chamber to the atmosphere is extended, so that the maintenance cost can be reduced.
[0017]
According to a sixth aspect of the present invention, in the plasma processing apparatus according to the fourth or fifth aspect, the detecting means includes a light emitting unit and a light receiving unit arranged with a peripheral member interposed therebetween. As described above, since the detection unit includes the light emitting unit and the light receiving unit arranged with the peripheral member interposed therebetween, light from the light emitting unit is initially blocked by the peripheral member and is not detected by the light receiving unit. When the surface of the member is worn and reaches a certain height, light is detected by the light receiving unit, whereby a predetermined amount of wear of the peripheral member can be detected.
[0018]
BEST MODE FOR CARRYING OUT THE INVENTION
A first embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a schematic sectional view showing an etching method using a dry etching apparatus which is a plasma processing apparatus according to a first embodiment of the present invention.
[0019]
As shown in FIG. 1, a substrate installation section (lower electrode 5) for installing a semiconductor substrate 2 to be processed by plasma 1 generated in a reaction chamber capable of being decompressed, and a peripheral member 3 provided around the substrate installation section. The peripheral member 3 is at least movable in a direction opposite to a direction in which the surface of the peripheral member 3 is consumed by the plasma 1.
[0020]
In this case, FIG. 1A shows an initial state of the dry etching apparatus according to the present embodiment, in which the semiconductor substrate 2 is installed in a reaction chamber capable of being evacuated or depressurized. . A lower electrode peripheral member 3 made of an insulating material is provided around a lower electrode 5 on which a semiconductor substrate 2 is installed and a plasma 1 is generated by applying a high-frequency voltage, and is supported by a support 4. The support 4 has a structure that can move up and down along the lower electrode 5 together with the peripheral member 3. That is, a protrusion 5 a is formed at the lower end of the lower electrode 5, and a hole 4 a to be fitted into the protrusion 5 a is formed in the support 4. In FIG. 1A, the peripheral member 3 is in a new state and does not wear. The peripheral member 3 and the lower electrode 5 are formed of the same material as that of the related art.
[0021]
In the above dry etching apparatus, when the semiconductor substrate 2 is installed on the lower electrode 5 and the semiconductor substrate 2 is subjected to plasma processing, after the surface of the peripheral member 3 provided around the lower electrode 5 is consumed by the plasma 1 by a predetermined amount, A step of moving the peripheral member 3 in a direction opposite to a direction in which the surface of the peripheral member 3 is consumed, and a step of continuing the plasma processing of the semiconductor substrate 2 after moving the peripheral member 3 are performed.
[0022]
That is, as the number of dry etching treatments of the semiconductor substrate 2 is increased, the surface of the peripheral member 3 is gradually consumed by the ion bombardment of the plasma by the plasma 1 of the etching gas in this apparatus as in the related art. As shown in FIG. 1B, the surface position of the peripheral member 3 is lowered as shown in FIG. 1B. When the surface position is lowered by a certain amount, the peripheral member 3 is moved upward. The semiconductor substrate 2 is moved in the opposite direction by the consumed distance so that the height of the semiconductor substrate 2 matches the surface height of the peripheral member 3 (FIG. 1C). By doing so, the positional relationship between the semiconductor substrate 2 and the peripheral member 3 can be returned to the initial state (FIG. 1A). Therefore, the plasma 1 during the dry etching also returns to the initial state, and a stable etching process can be maintained for a long time.
[0023]
FIG. 2 is a graph showing an example of the relationship between the number of processed semiconductor substrates (wafers) in the dry etching process and the thickness of the lower electrode peripheral members. As shown in FIG. 2, it can be seen that the members are consumed at a constant rate. Conventionally, if the member is replaced when the consumption of the lower electrode peripheral member exceeds 2 mm, for example, the replacement cycle is after about 3,000 sheets have been processed. On the other hand, in the case of the present invention, when the initial peripheral member thickness is 30 mm, and the minimum necessary member thickness in the dry etching apparatus is 20 mm, the allowable consumption amount is 10 mm, and the number of semiconductor substrate processing to be performed before the replacement of the member is about 10 mm. The number of replacement maintenance work can be increased fivefold, and the replacement cycle of members can be extended fivefold. As a result, the operating rate of the etching apparatus increases, and the equipment maintenance cost can be reduced by the present invention.
[0024]
A second embodiment of the present invention will be described with reference to FIGS. FIG. 3 is a schematic sectional view showing an etching method using a dry etching apparatus which is a plasma processing apparatus according to a second embodiment of the present invention.
[0025]
As shown in FIG. 3, a substrate installation section (lower electrode 5) for installing a semiconductor substrate 2 to be processed by plasma 1 generated in a reaction chamber capable of being decompressed, and a peripheral member 3 provided around the substrate installation section. Detecting means 8 and 9 for detecting that the surface of the peripheral member 3 has been consumed by the plasma 1 by a predetermined amount, and based on the detection results of the detecting means 8 and 9, the peripheral member 3 At least in the opposite direction.
[0026]
In this case, FIG. 3A shows an initial state of the internal structure of the dry etching apparatus according to the present embodiment. Although not shown, this apparatus is characterized in that a laser light emitting unit 8 and a laser light receiving unit 9 are provided in the reaction chamber wall as detection means in a horizontal arrangement with the peripheral member 3 interposed therebetween. The other structure is the same as that of the apparatus shown in FIG. 1A. A support 4 that can move up and down around a lower electrode 5 on which the semiconductor substrate 2 is placed, and a lower electrode peripheral member attached to the support 4 3, the height of the horizontal surface of the peripheral member 3 is higher than the height of the semiconductor substrate 2. The laser beam from the laser emitting section 8 is initially blocked by the peripheral member 3.
[0027]
In the above dry etching apparatus, when the semiconductor substrate 2 is placed on the lower electrode 5 and the semiconductor substrate 2 is subjected to plasma processing, the surface of the peripheral member 3 provided around the lower electrode 5 is consumed by the plasma 1 by a predetermined amount. A detecting step, after detecting that the peripheral member 3 has been consumed by a predetermined amount, a step of moving the peripheral member 3 by a distance corresponding to the consumed amount in a direction opposite to the direction in which the surface of the peripheral member 3 has been consumed, and moving the peripheral member 3 Thereafter, a step of continuing the plasma processing of the semiconductor substrate 2 is performed.
[0028]
That is, as the number of dry etching treatments of the semiconductor substrate 2 increases, the surface of the lower electrode peripheral member 3 is consumed, and the laser beam 10 reaches the laser light receiving section 9 as shown in FIG. The light receiving signal is sent to the up / down movement variable mechanism that is linked to, and the lower electrode peripheral member 3 is automatically raised by a predetermined amount. As a result, the height of the lower electrode peripheral member 3 can be returned to the initial state (FIG. 3A) as shown in FIG. 3C, and a stable process with little fluctuation of etching plasma can be performed. The frequency of member replacement can be reduced, and maintenance costs can be reduced.
[0029]
In the first embodiment, it is necessary to count the number of dry-etched semiconductor substrates, and manually adjust the height of the peripheral members when the number of processed semiconductor substrates reaches a certain number. 3 can be automatically detected and adjusted to a certain height. For example, if the laser light 10 is applied to the side of the peripheral member 0.5 mm below the surface of the peripheral member, the laser light 10 is processed by the laser receiving unit 9 after processing about 750 substrates from the data of FIG. It is detected and the height is adjusted automatically. When the height adjustment is automated in this manner, the surface position of the peripheral member 3 can be returned to the initial state before the wear of the peripheral member 3 becomes large, so that the dry etching process conditions can be further stabilized.
[0030]
Next, the peripheral member height adjustment control system of the dry etching apparatus shown in FIG. 3 and its control flow will be described. FIG. 4 is a schematic diagram showing a configuration of a height control system of the dry etching apparatus of FIG. 3, and FIG. 5 is a flowchart showing a control procedure thereof.
[0031]
As shown in FIG. 4, an operation unit 13 which receives the detection signals from the detection means 8 and 9 to determine whether the peripheral member 3 can be moved up and down and transmits a movement signal based on the determination result, A movement control unit 12 for moving the peripheral member 3 by a predetermined distance in a direction opposite to a direction in which the surface is worn.
[0032]
In the initial state of the apparatus, the laser beam 10 is shielded from light by the lower electrode peripheral member 3, but the surface is consumed by the plasma in the reaction chamber (chamber) 11 so that the laser beam is received by the laser receiving section 9 as shown in FIG. The laser beam 10 is received (S1 to S3).
[0033]
The detection signal indicating the light reception is input from the laser light receiving section 9 to the CPU (calculation device) 13 in the apparatus (S4). Next, the CPU 13 performs an automatic calculation for judging whether or not the vertical movement is possible (S5), and issues an output signal for each of the improper (NG or OK) (S6).
[0034]
If the vertical movement is possible, a movement signal is issued to the vertical movement variable mechanism 12 interlocked with the support 4 of the peripheral member 3 (S7), and the movement is performed by a predetermined distance whose surface has been consumed (S8). . As a result, the laser beam 10 is shielded again (S9), and the semiconductor substrate can be processed (S1).
[0035]
Further, for example, when the lower electrode peripheral member 3 has been considerably consumed to the extent of its allowable thickness, and it is determined that vertical movement is not possible, the CPU 13 issues an alarm display signal (S10), and an alarm prompting replacement work of the peripheral member 3 is made. Is displayed on the device monitor (CRT) 14. After the processing of one semiconductor substrate at the time of alarm generation is completed, the next processing is not performed (S11). Then, the variable mechanism 12 for vertically moving the support body 4 automatically moves to the same position where the new peripheral member 3 is mounted as shown in FIG. 3A (S12), so that the replacement work can be performed. (S13).
[0036]
The peripheral member surface position detecting mechanism provided in the dry etching apparatus according to the second embodiment described above is applied to an apparatus in which the surface of the lower electrode peripheral member 3 is originally higher than the semiconductor substrate 2. However, it is difficult to apply the method to an apparatus having an arrangement in which the substrate 2 and the surface must be substantially at the same height as shown in FIG. This can be solved by using a third embodiment described below.
[0037]
A third embodiment of the present invention will be described with reference to FIG. FIG. 6 is a schematic sectional view showing an etching method using a dry etching apparatus which is a plasma processing apparatus according to a third embodiment of the present invention.
[0038]
As shown in FIG. 6, as in the second embodiment, a substrate mounting section (lower electrode 5) for mounting a semiconductor substrate 2 to be processed by plasma 1 generated in a reaction chamber capable of being decompressed, A peripheral member provided around the peripheral member; and detecting means for detecting that the surface of the peripheral member has been consumed by the plasma by a predetermined amount, and detecting the peripheral member based on a detection result of the detecting means. 3 is at least movable in a direction opposite to the direction in which its surface is worn.
[0039]
In the initial state of the etching process in this apparatus, the semiconductor substrate 2 and the surface of the peripheral member 3 are at the same position. Although not shown, the laser emitting section 8 and the laser receiving section 9 are fixedly installed at appropriate places on the wall surface of the reaction chamber. At this time, the laser light emitting section 8 irradiates the end of the lower electrode peripheral member 3 with laser light 10 from obliquely upward to the outside, and the laser light receiving section 9 is obliquely downward so as to be able to receive it.
[0040]
Immediately after the replacement of the peripheral member 3, the laser light 10 is blocked at the peripheral member end as shown in FIG. 6A, but when the number of etched semiconductor substrates 2 increases and the time of exposure to the plasma 1 increases to some extent, the surface The laser light 10 is received by the laser receiving unit 9 as shown in FIG. Then, as shown in FIG. 6C, the support 4 is moved upward to return the surface of the peripheral member 3 to the initial position. In this way, the laser light 10 is shielded again, and the etching plasma returns to the initial state, so that a stable process can be maintained without replacing the peripheral member 3.
[0041]
In the above example, the case where the laser light emitting unit 8 is located on the upper side has been described. However, the positions of the laser light emitting unit 8 and the light receiving unit 9 may be exchanged, and the end of the peripheral member 3 may be irradiated with laser light from diagonally below. . Other configuration effects are the same as those of the second embodiment.
[0042]
【The invention's effect】
According to the plasma processing method according to the first aspect of the present invention, after the surface of the peripheral member provided around the substrate mounting portion is consumed by the plasma by a predetermined amount, the peripheral member is consumed in a direction opposite to the direction in which the peripheral member is consumed. The method includes a step of moving the peripheral member by a distance corresponding to the amount and a step of continuing the plasma processing of the substrate after moving the peripheral member, so that the surface of the peripheral member is consumed by plasma and the relative position with respect to the substrate fluctuates. Even so, the position of the surface can be restored. Therefore, since the width of the plasma generation region is constant, the fluctuation of the plasma state is suppressed, the process characteristics are stabilized, and plasma processing such as dry etching can be performed stably. Further, the replacement cycle of the peripheral members is extended, and the cost for maintenance can be reduced.
[0043]
According to the plasma processing method of the second aspect of the present invention, the step of detecting that the surface of the peripheral member provided around the substrate installation portion has been consumed by the plasma by a predetermined amount, and the step of detecting that the surface has been consumed by the predetermined amount A step of moving the peripheral member in a direction opposite to the direction in which the surface of the peripheral member has been consumed by a distance corresponding to the amount of consumption, and a step of continuing the plasma processing of the substrate after moving the peripheral member. Even if the surface is consumed by the plasma and its relative position to the substrate fluctuates, the position of the surface can be returned to the original position by detecting a predetermined amount of consumption and raising the peripheral member by a predetermined amount. Therefore, since the width of the plasma generation region is constant, the fluctuation of the plasma state is suppressed, the process characteristics are stabilized, and plasma processing such as dry etching can be performed stably. Further, the replacement cycle of the peripheral members is extended, and the cost for maintenance can be reduced.
[0044]
According to the plasma processing apparatus according to the third aspect of the present invention, the peripheral member is at least movable in a direction opposite to a direction in which the surface of the peripheral member is consumed by the plasma. It is easy to return the surface position to its original position even if the relative position with respect to fluctuates. Therefore, the variation in the plasma state is suppressed by stabilizing the width of the plasma generation region, and the process characteristics can be stabilized. Further, the maintenance work cycle for exchanging peripheral members by exposing the reaction chamber in a vacuum or reduced pressure state to the atmosphere can be extended, and therefore, equipment maintenance costs and production costs can be reduced.
[0045]
According to the plasma processing apparatus of the fourth aspect of the present invention, the peripheral member determines the direction in which the surface is consumed based on the detection result of the detecting means for detecting that the surface of the peripheral member has been consumed by a predetermined amount due to the plasma. Since the peripheral member is at least movable in the opposite direction, even if the surface of the peripheral member is consumed by the plasma and the relative position with respect to the substrate fluctuates, the detecting means detects a predetermined amount of consumption and raises the peripheral member by a predetermined amount. Thus, the position of the surface can be restored. Therefore, the variation in the plasma state is suppressed by stabilizing the width of the plasma generation region, and the process characteristics can be stabilized. Further, the maintenance work cycle for exchanging peripheral members by exposing the reaction chamber in a vacuum or reduced pressure state to the atmosphere can be extended, and therefore, equipment maintenance costs and production costs can be reduced.
[0046]
According to the plasma processing apparatus of the present invention, the detecting means for detecting that the surface of the peripheral member has been consumed by the plasma by a predetermined amount, and the peripheral member cannot be moved up and down in response to a detection signal from the detecting means. A calculation unit for making a determination and transmitting a movement signal based on the determination result; and a movement control unit for moving the peripheral member a predetermined distance in a direction opposite to a direction in which the surface is worn out based on the movement signal. Even if the surface of the member is consumed by the plasma and the relative position with respect to the substrate fluctuates, the surface of the member is restored by detecting the predetermined amount of consumption and raising the peripheral member by the predetermined amount. Can be. At this time, the detection signal from the detection means is input to the arithmetic unit, and an automatic calculation for determining whether or not the vertical movement is possible is performed. If the vertical movement is possible, a movement signal is transmitted to the movement control unit. Then, the surface is raised by a predetermined distance which has been consumed. Therefore, the variation in the plasma state is suppressed by stabilizing the width of the plasma generation region, and the process characteristics can be stabilized. Further, the maintenance work cycle for exchanging peripheral members by exposing the reaction chamber in a vacuum or reduced pressure state to the atmosphere can be extended, and therefore, equipment maintenance costs and production costs can be reduced.
[0047]
According to claim 6, since the detecting means includes the light emitting unit and the light receiving unit arranged with the peripheral member interposed therebetween, light from the light emitting unit is initially blocked by the peripheral member and is not detected by the light receiving unit. When the surface of the peripheral member is worn and reaches a certain height, light is detected by the light receiving unit, whereby a predetermined amount of consumption of the peripheral member can be detected.
[Brief description of the drawings]
FIG. 1 is a schematic sectional view showing an operation of a main part of a dry etching apparatus according to a first embodiment of the present invention.
FIG. 2 is a diagram illustrating a relationship between the number of plasma-processed semiconductor substrates and a change in thickness due to plasma consumption of a lower electrode peripheral member;
FIG. 3 is a schematic sectional view showing an operation of a main part of a dry etching apparatus according to a second embodiment of the present invention.
FIG. 4 is a block diagram schematically showing a lower electrode peripheral member vertical movement control system in a dry etching apparatus according to a second embodiment of the present invention.
FIG. 5 is a flowchart of a lower electrode peripheral member vertical movement control system in a dry etching apparatus according to a second embodiment of the present invention.
FIG. 6 is a schematic sectional view showing an operation of a main part of a dry etching apparatus according to a third embodiment of the present invention.
FIG. 7 is a schematic sectional view showing a configuration of a main part of a conventional dry etching apparatus.
FIG. 8 is an explanatory view showing wear of a lower electrode peripheral member in a conventional dry etching apparatus.
[Explanation of symbols]
1 Plasma
2 Semiconductor substrate
3 Peripheral members
4 Support
5 Lower electrode (board installation part)
6 Peripheral member pedestal
7 Parts consumed by plasma
8 Laser emitting part
9 Laser receiver
10 Laser light
11 Reaction chamber
12 Vertical movement control unit
13 CPU
14 CRT

Claims

When the substrate is placed on the substrate mounting portion and the substrate is subjected to plasma processing, after the surface of the peripheral member provided around the substrate mounting portion is consumed by a predetermined amount due to the plasma, a direction opposite to the direction in which the surface of the peripheral member is consumed is consumed. A plasma processing method comprising: moving the peripheral member in a direction by a distance corresponding to a consumption amount; and continuing plasma processing of the substrate after moving the peripheral member.

A step of detecting that a surface of a peripheral member provided around the substrate installation portion has been consumed by a predetermined amount by plasma when the substrate is plasma-processed by installing the substrate in the substrate installation portion; and After the detection, a step of moving the peripheral member by a distance corresponding to a consumption amount in a direction opposite to a direction in which the surface of the peripheral member is consumed, and a step of continuing the plasma processing of the substrate after moving the peripheral member. And a plasma processing method.

A substrate installation section for installing a substrate to be processed by plasma generated in a reaction chamber that can be decompressed, and a peripheral member provided around the substrate installation section, wherein the peripheral member is formed of the peripheral member by the plasma. A plasma processing apparatus characterized by being movable at least in a direction opposite to a direction in which a surface is consumed.

A substrate installation section for installing a substrate to be processed by plasma generated in a reaction chamber capable of being depressurized; a peripheral member provided around the substrate installation section; and a predetermined amount of surface of the peripheral member being consumed by the plasma. A plasma processing apparatus, wherein the peripheral member is at least movable in a direction opposite to a direction in which a surface thereof is consumed, based on a detection result of the detection means.

A substrate installation section for installing a substrate to be processed by plasma generated in a reaction chamber capable of being depressurized; a peripheral member provided around the substrate installation section; and a predetermined amount of surface of the peripheral member being consumed by the plasma. Detecting means for detecting the detection signal from the detection means, performing a determination as to whether or not the peripheral member can move up and down, and transmitting a movement signal based on the determination result; and A plasma processing apparatus comprising: a movement control unit configured to move a peripheral member a predetermined distance in a direction opposite to a direction in which the surface is worn.

The plasma processing apparatus according to claim 4, wherein the detection unit includes a light emitting unit and a light receiving unit arranged with a peripheral member interposed therebetween.