JP4647122B2 - Vacuum processing method - Google Patents

Description

【００２４】
上記の表１に示された、静電吸着力の時間依存性より、吸着電極に電圧印加を開始してから５秒経過した時点での吸着力は４．５０ｇｆ／cm²になっている。この実験に用いた基板の厚みが１cmの場合に、その基板の重さと釣り合う吸着力は２．４７ｇf／cm²であるので、厚さ３mmの基板を吊り上げるためには、余裕をみても３ｇｆ／cm²程度の吸着力があれば十分である。すなわち、ここでの最小吸着力は３ｇｆ／cm²である。これより吸着電極に電圧印加を開始してから５秒経過すれば、基板を静電吸着して吊り上げることができることがわかる。
【００２５】
しかしながら、吸着電極に６０秒間電圧を印加した後の残留吸着力の時間依存性をみると、電圧印加が終了した時刻から６０秒経過した時点で、残留吸着力は３１ｇｆ／cm²までしか減少していない。基板を安全に離脱させるためには、残留吸着力は、上述した最小吸着力(ここでは３ｇｆ／cm²)の８割程度の吸着力(ここでは２．４ｇｆ／cm²)以下まで低下することが必要であるが、６００秒経過しても残留吸着力は２５．５ｇｆ／cm²までしか低下していないので、基板を安全に離脱させることはできない。このように、１枚の基板を６０秒間吸着した後に、６００秒以上経過しても基板を離脱することができないのでは、到底実用に堪えない。
【００２６】
上記の表１で行った実験と同じ基板及び同じ静電吸着装置を用いて、吸着電極に印加する電圧を低圧(ここでは、二個の吸着電極にそれぞれ＋７５０Ｖ、−７５０Ｖを印加している)にして、同様の実験を行った。下記の表２に、その場合の、静電吸着装置とその基板との間に生じる静電吸着力の時間依存性を調べた実験の結果と、吸着電極に６０秒間電圧を印加して基板を静電吸着した後、各吸着電極に０Ｖを印加し、その時刻以降に基板及び静電吸着装置間に残留する残留吸着力の時間依存性を調べる実験の結果とを示す。
【００２７】
【表２】

【００２８】
上記の表２に示された、静電吸着力の時間依存性より、吸着力が最小吸着力(ここでは３ｇｆ／cm²)以上になるには電圧印加開始から１０秒では足りず、１０秒以上６０秒以下のある時刻で最小吸着力以上になることがわかる。電圧印加開始から５秒経過した時点での吸着力は０．２ｇｆ／cm²程度であって、基板をつり上げることは到底できないことがわかる。
【００２９】
また、６０秒間静電吸着した後の残留吸着力は小さくなっているが、電圧印加停止から６０秒経過すると、２．７ｇｆ／cm²程度までしか低下しておらず、静電吸着装置が、基板を安全に離脱することが可能な吸着力(ここでは２．４gｆ／cm²)までは低下しない。
【００３０】
以上より、同一の高電圧を吸着電極に印加し続けた場合には、比較的短時間に基板を吸着して保持することが可能になるものの、吸着力が過度に大きくなり、その後基板を離脱させるのに長時間を要してしまうことがわかり、他方、同一の低電圧を吸着電極に印加し続けた場合には、残留吸着力は過度に大きくならないものの、基板を保持可能な程度の吸着力に達するまでに長時間を要し、残留吸着力が基板を静電吸着装置から安全に離脱させるまでに要する時間もさほど短くならないことがわかった。
【００３１】
以上の結果を考察し、本発明の発明者等は、電圧印加開始から所定時間、吸着電極に高電圧を印加して吸着力を大きくした後、基板を吸着した状態で吸着電極に印加する電圧を変更して吸着力を小さくすれば、吸着力は過度に大きくならないので、短時間で基板を吸着した後、短時間で基板を脱離することができるのではないかと推測した。
【００３２】
本発明の発明者等は、この推測を確認すべく、表１等に示した実験で用いたものと同じ基板及び静電吸着装置を用い、各吸着電極に５秒間高電圧を印加した後(ここでは、二個の吸着電極にそれぞれ＋３０００Ｖ、−３０００Ｖを印加する)、印加電圧を低電圧（ここでは、二個の吸着電極にそれぞれ＋７５０Ｖ、−７５０Ｖを印加している)にし、その場合における吸着力の時間依存性を調べる実験と、その実験と同じ条件で吸着電極に合計６０秒間電圧を印加した後に、各吸着電極に印加する電圧を０Ｖにし、０Ｖにした時刻以降に生じる残留吸着力の時間依存性を調べる実験とを行った。これらの実験結果を下記の表３に示す。
【００３３】
【表３】

【００３４】
上記の表３に示した吸着力の時間依存性からは、電圧印加開始から５秒経過した時点で、吸着力は４．５gｆ／cm²に達しており、基板を吸着して保持することが可能になっており、その後、６０秒経過した時点でも、吸着力は４．９gｆ／cm²程であり、最小吸着力以上になっており、基板を十分吸着して保持できる程度の大きさを維持していることがわかる。
【００３５】
また、表３に示した残留吸着力の時間依存性からは、吸着電極への電圧印加を終了した時点での残留吸着力は４．９gｆ／cm²であるが、電圧印加を終了してから６０秒経過した時点での残留吸着力は３．１gｆ／cm²まで低下しており、残留吸着力は、一定電圧を印加し続けている場合に比して、相当小さくなっていることがわかる。
【００３６】
このように、最初、吸着力が大きくなる高電圧を吸着電極に印加し、短時間で基板を吸着保持した後に、基板を吸着保持している間に、吸着電極に印加する電圧を低下させて吸着力を低下させることにより、短時間で基板を吸着・保持し、また、短時間で基板を離脱させられることが確認できた。
【００３７】
本発明は、かかる知見に基づいて創作されたものであって、基板を静電吸着装置に当接させた状態で静電吸着装置内の電極に第１の電圧を印加した後に、電極に印加する電圧を第２の電圧に変更している。
【００３８】
このとき、予め、処理対象となる基板について、基板を静電吸着可能な力の最小値である最小吸着力を求め、基板を処理する時間に応じて、第１、第２の電圧の大きさ、印加時間、基板の処理の開始時刻及び終了時刻等の値について適当な値を求めておく。こうして求められた適当な値に従い、電極に第１の電圧を印加して静電吸着力を最小吸着力以上の大きさにして、静電吸着装置に基板を静電吸着した後に基板の処理を開始し、基板の処理中に電極に印加する電圧を第２の電圧に変更すると、第２の電圧に変更された後に静電吸着力が減少し、かつ基板の処理が終了するまでの間に、静電吸着力を最小吸着力以上に維持して、基板を静電吸着装置に静電吸着し続けることができる。
【００３９】
このように構成することにより、基板の処理が終了した時点では、同一電圧を電極に印加していた従来に比して残留電荷の量が少なくなり、残留吸着力が低下するので、静電吸着装置から基板を離脱させられるまでに要する時間を、従来に比して短縮することができる。
【００４０】
特に、その後電極に逆極性の電圧を印加して残留電荷を短時間で消滅させ、吸着力を０にする場合には、逆極性の電圧を印加する直前まで印加していた第２の電圧よりも絶対値が小さい電圧を印加しても、短時間で残留電荷を消滅させることができる。従って、従来のように高圧出力の静電吸着電源を必要としないので、装置全体のコストが高くならず、また、静電吸着装置とその周辺装置との間の放電や、吸着電極間での放電等により故障等が生じにくくなる。
【００４１】
なお、本発明において、静電吸着力が最小吸着力よりも大きい上限吸着力を上回る前に、電極に印加する電圧を第２の電圧に変更するように構成してもよい。
ここで上限吸着力とは、基板を静電吸着装置に静電吸着した状態で処理する間に、吸着力が最小吸着力以上を維持し、かつ処理が終了した後に、静電吸着装置から基板を安全に離脱させるのに十分な力まで低下することが可能な吸着力の上限である。この上限吸着力は、静電吸着装置内の電極に印加する電圧と、基板の処理時間とに応じて定まり、吸着力が上限吸着力を超えると、基板の処理が終了した後、残留吸着力が過大になり、静電吸着装置から基板を安全に離脱することができなくなる。
【００４２】
かかる上限吸着力を吸着力が上回る前に、電極に印加する電圧を第２の電圧に変更し、吸着力を減少させることにより、基板の処理が終了した時点で、残留吸着力は、静電吸着装置から基板を安全に離脱させられる程度まで低下しているので、処理終了後、速やかに基板を安全に離脱させることができる。
【００４３】
また、本発明において、静電吸着装置が有する電極は、２個の電極からなり、第１又は第２の電圧を電極に印加する際には、各電極に互いに極性の異なる電圧を印加するように構成してもよい。その場合、電極に印加する電圧を第２の電圧に変更して、静電吸着力を減少させる工程では、２個の電極の間の電位差を、第１の電圧が印加された工程における２個の電極の電位差よりも小さくするように構成してもよい。このように構成することにより、第２の電圧に変更した後の吸着力は、第１の電圧が印加されたときの電圧よりも小さくなる。
【００４４】
また、電極に印加する電圧を第２の電圧に変更して、静電吸着力を減少させる工程では、２個の電極の間の電位差を、０ボルトにするように構成してもよいし、また、第１の電圧が印加された工程において、２個の電極に印加された電圧と逆極性の電圧を、２個の電極にそれぞれ印加するように構成してもよい。このように構成することにより、第２の電圧を印加した後の静電吸着力の減少量を大きくすることができる。
【００４５】
【発明の実施の形態】
以下で図面を参照し、本発明の実施形態について説明する。図１の符号１は、本発明の真空処理方法に用いる真空処理装置を示している。
この真空処理装置１は、搬出入室２と、搬送室３と、処理室４とを有している。これらの搬出入室２、搬送室３及び処理室４には、真空排気系７２、７３、７４がそれぞれ接続されており、これらの真空排気系７２、７３、７４を起動すると、各搬出入室２、搬送室３及び処理室４の内部を真空排気することができるように構成されている。
【００４６】
搬送室３内部には、搬送ロボット１０が配置されている。この搬送ロボット１０は、駆動機構１１と、アーム１２と、静電吸着装置１３とを有している。
駆動機構１１は、搬送室３の内部底面に配置されている。
【００４７】
アーム１２は、その一端が駆動機構１１の先端に取り付けられており、駆動機構１１を動作させると、水平面内で自由に移動できるように構成されている。アーム１２の先端には静電吸着装置１３が配置されている。
【００４８】
この静電吸着装置１３の構成を図２(ａ)、(ｂ)に示す。この静電吸着装置１３は、金属板２４と、該金属板２４上に配置された誘電体層２５を有している。誘電体層２５はＡｌ₂Ｏ₃を主成分とするセラミックス製であり、その表面には、Ａｌから成る第１、第２の吸着電極２７₁、２７₂が形成されている。
【００４９】
第１、第２の吸着電極２７₁、２７₂の平面図を同図(ｂ)に示す。第１、第２の吸着電極２７₁、２７₂は櫛状に成形されており、その歯の部分が互いに噛み合うように配置されている。同図(ａ)は同図(ｂ)のＸ−Ｘ線断面図に相当する。第１、第２の吸着電極２７₁、２７₂の幅は４ｍｍ、電極間の間隔は１ｍｍとしており、電極の厚みを１０μｍとしている。
【００５０】
かかる静電吸着装置１３は、第１、第２の吸着電極２７₁、２７₂が配置された面が鉛直下方を向くように、上述したアーム１２の先端に取り付けられており、アーム１２が水平面内で移動すると、第１、第２の吸着電極２７₁、２７₂の配置された面が鉛直下方に向いた状態で、アーム１２とともに水平面内で自由に移動することができるように構成されている。
【００５１】
第１、第２の吸着電極２７₁、２７₂は、それぞれ搬送室３外に設けられた静電吸着電源１５に接続されており、その静電吸着電源１５を駆動すると、第１、第２の吸着電極２７₁、２７₂の間に直流電圧を印加することができるように構成されている。
【００５２】
上述した構成の真空処理装置１を用いて、搬出入室２から処理室４に基板を搬送する基板搬送処理について以下で説明する。
予め、図３に示すように、搬出入室２、搬送室３及び処理室４の内部雰囲気はそれぞれ独立に真空排気されており、その状態で駆動機構１１を動作させてアーム１２を水平移動させ、静電吸着装置１３を搬出入室２内に搬入し、搬出入室２内の載置台６の表面に載置された基板５０の上方に位置させて静止させる。
【００５３】
次に、図４に示すように、基板５０表面を、静電吸着装置１３の表面に接触させる。ここでは、昇降ピン６０上に基板５０を載せ、昇降ピン６０を上昇させて基板５０を上方に移動させることにより、基板５０表面を静電吸着装置１３の表面に接触させている。
【００５４】
次いで、静電吸着電源１５を起動し、静電吸着装置１３の第１、第２の吸着電極２７₁、２７₂間に、所定の第１の電圧を印加する。(ここでは、第１、第２の吸着電極２７₁、２７₂にそれぞれ＋３０００Ｖ、−３０００Ｖを印加している)。すると、静電吸着装置１３と基板５０との間に静電吸着力が生じる。この静電吸着力は、電圧印加時間に応じて増大する。静電吸着力が増大し、静電吸着装置１３が基板５０を静電吸着した状態で安全に移動させられる力の最小値(以下で最小吸着力と称する。)以上の値になると、基板５０は静電吸着装置１３の表面に吸着されて保持される。その状態を図５に示す。吸着保持されたら、昇降ピン６０を下降させて載置台６内に収納する。
【００５５】
次に、アーム１２を水平移動させ、基板５０を吸着した状態で静電吸着装置１３を搬出入室２から搬送室３へと移動させ、処理室４内へ搬入する。この移動の間に、静電吸着装置１３の第１、第２の吸着電極２７₁、２７₂に印加する電圧を第２の電圧(ここでは、第１、第２の吸着電極２７₁、２７₂にそれぞれ＋７５０Ｖ、−７５０Ｖを印加している)に変更する。具体的には、第１の電圧の印加が開始してから５秒間経過した後、印加電圧を第２の電圧に変更している。第２の電圧に変更された後には静電吸着力は低下するが、基板５０はまだ静電吸着装置１３に静電吸着された状態で保持されている。
【００５６】
処理室４の内部底面には、載置台４８が配置され、載置台４８上には、後に詳述する静電チャックプレート４０が配置されている。この静電チャックプレート４０上方の所定位置に静電吸着装置１３が位置したら、静電吸着装置１３を静止させる。その状態を図６に示す。
【００５７】
載置台４８及び静電チャックプレート４０内部には、これらを挿通して昇降可能な昇降ピンが配置されている。静電吸着装置１３が静電チャックプレート４０の上方位置で静止したら、図７に示すように昇降ピン６１を上昇させ、静電吸着装置１３の下方に下向きに保持された基板５０の表面に当接させる。
【００５８】
その後、第１、第２の吸着電極２７₁、２７₂に、直前まで印加していた第２の電圧と逆極性の所定電圧を印加する。具体的には、−３００Ｖ、＋３００Ｖを第１、第２の吸着電極２７₁、２７₂にそれぞれ印加している。
【００５９】
こうして逆極性の電圧が印加されると、基板５０と静電吸着装置１３との間の残留電荷が急激に減少して消滅し、静電吸着力はほぼ０になり、基板５０は静電吸着装置１３から容易に離脱可能な状態になる。その状態で、昇降ピン６１を下降させると、基板５０は静電吸着装置１３から離脱して、昇降ピン６１の上端に載せ替えられ、昇降ピン６１とともに下降する。昇降ピン６１が完全に載置台４８の内部に収納されると、基板５０は静電チャックプレート４０表面に載置される。その状態を図８に示す。以上の工程を経て、基板５０の搬出入室２から処理室４への搬送処理が終了する。
【００６０】
図１０に、上述した基板搬送処理における、第１、第２の吸着電極２７₁、２７₂間に印加する電圧及び基板５０と静電吸着装置１３との間の静電吸着力の時間変化を示す。図１０の曲線(Ａ)は、第１、第２の吸着電極２７₁、２７₂間に印加される電圧の時間変化を示しており(簡便にするため、第１の吸着電極２７₁の電圧を示している。)、曲線(Ｂ)は、基板５０と静電吸着装置１３との間に生じる静電吸着力の時間変化を示している。
【００６１】
図中、符号Ｖ₁は、第１、第２の吸着電極２７₁、２７₂間に最初に印加する第１の電圧(ここでは、第１、第２の吸着電極２７₁、２７₂にそれぞれ＋３０００Ｖ、−３０００Ｖを印加している)を示しており、符号Ｖ₂は、第１の電圧Ｖ₁を所定時間(ここでは５秒間)印加した後、第１、第２の吸着電極２７₁、２７₂間に印加する第２の電圧(ここでは、第１、第２の吸着電極２７₁、２７₂にそれぞれ＋７５０Ｖ、−７５０Ｖを印加している)を示している。また符号ｆ₁は最小吸着力を示している。
【００６２】
また、符号ｔ₁は第１、第２の吸着電極２７₁、２７₂間に電圧の印加を開始した時刻を示しており、符号ｔ₂は、静電吸着装置１３が移動を開始した時刻を示している。また、符号ｔ₃は静電吸着装置１３を基板５０を吸着した状態で移動を終了した時刻を示し、時刻ｔ_hは、印加電圧を第１の電圧Ｖ₁から第２の電圧Ｖ₂へと変更した時刻を示している。また、符号ｔ₄は、第１、第２の吸着電極２７₁、２７₂間に、直前に印加していた第２の電圧Ｖ₂と逆極性の電圧を印加し始めた時刻を示し、符号ｔ₅は、その逆極性の電圧の印加を終了した時刻を示しており、時刻ｔ₆は、基板５０を静電吸着装置１３から離脱させた時刻を示している。
【００６３】
上述した基板搬送処理においては、図１０の曲線(Ａ)に示すように、基板５０を吸着した静電吸着装置１３が時刻ｔ₂で移動を開始してから、時刻ｔ₃で移動を終了するまでの時間(ここでは６０秒間)に、時刻ｔ_hで第１、第２の吸着電極２７₁、２７₂間に印加する電圧を第１の電圧Ｖ₁から第２の電圧Ｖ₂へと変更している。
【００６４】
予め、最小吸着力ｆ₁や、これら第１、第２の電圧Ｖ_1、Ｖ₂の電圧値、印加時間は適当な値に設定されており、その結果、印加電圧を第２の電圧Ｖ₂に変更した時刻ｔ_h以降、吸着力は低下するが、移動が終了する時刻ｔ₃までの間には、曲線(Ｂ)に示すように、吸着力は最小吸着力ｆ₁以上の値になり、基板５０を吸着して移動を開始してから移動が終了するまでの間(６０秒間)は、基板５０が静電吸着装置１３から落下しないようになっている。
【００６５】
また、基板を移動させる途中で吸着力が減少するので、吸着力は過度に大きくならず、移動が終了した時刻ｔ₃における吸着力は、従来に比して小さくなる。このため、移動終了後に、時刻ｔ₄〜ｔ₅の間(ここでは２秒間)に逆極性の電圧を第１、第２の吸着電極２７₁、２７₂間に印加して、短時間で残留電荷を消滅させる場合にも、従来のように、直前まで印加していた電圧よりも絶対値の大きい電圧を印加する必要がなく、直前まで印加していた第２の電圧Ｖ₂より低い電圧を印加(ここでは、第１、第２の吸着電極２７₁、２７₂にそれぞれ−３００Ｖ、＋３００Ｖを印加している)することにより、短時間で吸着力をほぼ０にし、静電吸着装置１３から基板５０を容易に離脱させることができる。
【００６６】
従って、静電吸着電源１５を高圧出力の電源で構成する必要がないので、静電吸着電源１５のコストを低減し、ひいては装置全体のコストを低減することができる。また、静電吸着装置１３とその周辺装置との間で放電が生じたり、第１、第２の吸着電極２７₁、２７₂間で放電が生じることで、装置の故障等が生じることもない。
【００６７】
なお、上述した基板搬送処理においては、図１０に示したように、第２の電圧Ｖ₂を、第１の電圧Ｖ₁と同じ極性で、第１の電圧Ｖ₁よりも低電圧の電圧とし、その後逆極性の電圧Ｖ₃を第１、第２の吸着電極２７₁、２７₂間に印加するものとしたが、本発明の基板搬送処理はこれに限られるものではなく、例えば、図１１の曲線(Ｃ)に示すように、第２の電圧Ｖ₂を、第１の電圧Ｖ₁と同じ極性で、第１の電圧Ｖ₁(ここでは、第１、第２の吸着電極２７₁、２７₂にそれぞれ＋３０００Ｖ、−３０００Ｖを印加している)よりも低電圧の第２の電圧Ｖ₂(ここでは第１、第２の吸着電極２７₁、２７₂にそれぞれ＋９５０Ｖ、−９５０Ｖを印加している)とした後、電圧を段階的に低下させるようにしてもよい。ここでは、３段階に電圧(図１１中のＶ₄〜Ｖ₆)を低下させた後に、逆極性の電圧Ｖ₃を第１、第２の吸着電極２７₁、２７₂間に印加している。
【００６８】
このように構成し、予め第１、第２の電圧Ｖ₁、Ｖ₂の電圧値、印加時間、移動開始時刻及び移動終了時刻を適当な値に設定することにより、図１０で説明したと同様に、図１１の曲線(Ｄ)に示すように、静電吸着装置１３の移動終了時刻ｔ₃までの間で、吸着力が最小吸着力ｆ₁以上になり、移動中に基板５０が静電吸着装置１３から落下しないようにすることができる。また、吸着力は過度に上昇せず、図中の符号ｆ₂に示す上限吸着力を超えない。このため、時刻ｔ₄で逆極性の電圧を第１、第２の吸着電極２７₁、２７₂間に短期間印加して、残留電荷を短時間で消滅させる場合にも、第２の電圧Ｖ₂以下の電圧を印加(ここでは、第１、第２の吸着電極２７₁、２７₂にそれぞれ−３００Ｖ、＋３００Ｖを印加している)することで、残留電荷を消滅させ、吸着力をほぼ０にし、基板５０を容易に静電吸着装置１３から離脱させることができる。
【００６９】
また、第１、第２の吸着電極２７₁、２７₂にともに０Ｖを印加し、図１２の曲線(Ｅ)に示すように、第２の電圧Ｖ₂を０Ｖとするように構成してもよい。このように構成することにより、同図の曲線(Ｆ)に示すように、第２の電圧Ｖ₂に変更した時刻ｔ_h以降、短期間で吸着力を減少させることができる。
【００７０】
さらに、図１３の曲線(Ｇ)に示すように、第２の電圧Ｖ₂として、第１の電圧Ｖ₁と逆極性の電圧を第１、第２の吸着電極２７₁、２７₂間に印加してもよい。このように構成すると、図１２に示し、第２の電圧Ｖ₂を０Ｖとした場合に比して、図１３の曲線(Ｈ)に示すように吸着力をさらに短期間で大きく減少させることができる。
【００７１】
また、上述した実施形態では、第２の電圧Ｖ₂を印加した後に、逆極性の電圧Ｖ３を印加して残留電荷を短時間で消滅させているが、本発明はこれに限られるものではなく、第１、第２の電圧Ｖ₁、Ｖ₂の電圧値や、印加時間等の値を適当な値に設定することで、逆極性の電圧Ｖ₃を印加しなくとも、短時間で残留電荷が消滅するように構成することも可能である。
【００７２】
以上説明した基板搬送処理が終了し、基板５０が静電チャックプレート４０の表面に載置されたら、アーム１２を水平移動させて静電吸着装置１３及びアーム１２を搬送室３内に退避させた後、処理室４内部に配置された弁８を閉じ、処理室４内部を搬送室３内部と遮断し、成膜処理に移行する。その状態を図９に示す。
【００７３】
静電チャックプレート４０は、例えばセラミックス材料等から成る誘電体板からなる。この静電チャックプレート４０内には、導電性材料からなる第１、第２の吸着電極４３、４４が配置されている。
【００７４】
第１、第２の吸着電極４３、４４は、静電チャックプレート４０内部の表面近傍に配置されている。これら第１、第２の吸着電極４３、４４は、処理室４の外部に配置されたチャック電源３１に接続されており、チャック電源３１を起動すると、第１、第２の吸着電極４３、４４の間に電圧を印加することができるように構成されている。
【００７５】
静電チャックプレート４０内部には、ヒータ４５が配置されている。このヒータ４５は、処理室４外部に配置されたヒータ電源３２に接続されており、ヒータ電源３２を起動すると、ヒータ４５を発熱させ、静電チャックプレート４０を昇温させることができるように構成されている。
【００７６】
処理室４内部の天井側には、静電チャックプレート４０と対向するように、例えばアルミなどの金属材料から成るターゲット３３が配置されている。このターゲット３３は、処理室４の外部に配置された直流電源３４に接続されており、直流電源３４を起動すると、処理室４に対して負の電圧が印加されるように構成されている。
【００７７】
基板５０が静電チャックプレート４０上に載置された状態では、予めヒータ４５は発熱し、静電チャックプレート４０は昇温されている。
この状態で、チャック電源３１を起動して、第１、第２の吸着電極４３、４４の間に、第１の電圧を印加(ここでは、第１、第２の吸着電極４３、４４に、それぞれ＋３０００Ｖ、−３０００Ｖを印加)すると、基板５０と静電チャックプレート４０との間に静電吸着力が発生する。この静電吸着力は電圧印加とともに増大し、最小吸着力以上になると基板５０は静電チャックプレート４０の表面に密着する。密着すると基板５０は静電チャックプレート４０からの熱伝導によって加熱される。
【００７８】
基板５０が加熱され、所定の温度まで昇温されたら、処理室４内に例えばアルゴンガス等のスパッタリングガスを導入する。静電チャックプレート４０は接地され、その上に載置された基板５０は接地されており、直流電源３４を起動してターゲット３３に負電圧を印加すると、ターゲット３３近傍に放電が生じ、処理室４内にプラズマが生成されてターゲット３３の材料がスパッタリングされ、スパッタリングされたターゲット３３材料からなる粒子が基板５０の表面に付着し、薄膜が成膜され始める。
【００７９】
薄膜の成膜が開始したら、第１、第２の吸着電極４３、４４の間に印加する電圧を変更し、第１の電圧より低電圧である第２の電圧を印加(ここでは、第１、第２の吸着電極４３、４４に、それぞれ＋７５０Ｖ、−７５０Ｖを印加)する。
ここでは、第１の電圧を５秒間印加した後に、印加電圧を第２の電圧に変更している。こうして印加電圧を第２の電圧Ｖ₂に変更することにより、吸着力は低下するが、静電チャックプレート４０と基板５０の表面が密着し、熱伝導で加熱可能な程度の吸着力は維持されている。
そして、基板５０の表面に所定膜厚の薄膜が形成された後に直流電源４を停止させ、プラズマを消滅させる。以上の工程を経て成膜処理が終了する。
【００８０】
こうして成膜処理が終了したら、第１、第２の吸着電極４３、４４の間に、成膜処理終了時に印加されていた電圧と逆極性の電圧を印加(ここでは、第１、第２の吸着電極４３、４４にそれぞれ−１００Ｖ、＋１００Ｖの電圧を印加)して、基板５０と静電チャックプレート４０との間の残留電荷を消滅させ、残留吸着力をほぼ０にし、基板５０を、静電チャックプレート４０の表面から容易に離脱出来る状態にした後、昇降ピン６１を上昇させ、静電チャックプレート４０の表面から基板５０を離脱させ、その後上述した搬送ロボット１０を用い、上述した基板搬送処理と同様の手順で基板５０を処理室４外へと搬出する。
【００８１】
成膜処理が終了するまで、一定の高電圧を第１、第２の吸着電極４３、４４の間に印加し続けた場合には、静電チャックプレート４０と基板５０との間の残留電荷が大量になり、吸着力が過度に大きくなるので、成膜処理終了後に、成膜処理終了時の電圧と逆極性の電圧を印加して短時間で残留電荷を消滅させる際に、成膜処理終了時の電圧よりも絶対値が大きい電圧を印加しなければならない。
【００８２】
しかしながら、本実施形態の成膜処理では、第１、第２の吸着電極４３、４４に最初に第１の電圧Ｖ₁を所定時間(ここでは５秒間)印加して基板５０と静電チャックプレート４０とを密着させた後、スパッタリングがなされている間に、印加する電圧を第２の電圧Ｖ₂に変更しており、第２の電圧Ｖ₂に変更した時刻以降は吸着力が減少し、残留電荷の量も減少するので、成膜処理が終了した時点では、基板５０と静電チャックプレート４０との間の吸着力は、一定電圧を印加し続けた場合に比して小さくなっている。
【００８３】
従って、成膜処理終了時の電圧よりも絶対値が小さく、かつ逆極性の電圧を印加することで、短時間で残留電荷を消滅させ、基板５０を静電チャックプレート４０表面から容易に離脱させることができる。
【００８４】
これにより、チャック電源３１を高圧出力の電源で構成しなくともよいので、チャック電源３１のコストを低減し、真空処理装置１のコストを低減することができる。また、静電チャックプレート４０とその周辺装置との間で放電が生じたり、第１、第２の吸着電極４３、４４間で放電が生じることで、装置の故障等が生じることもない。
【００８５】
なお、上述した実施形態では、真空処理方法として、基板を静電吸着した状態で基板を搬送する基板搬送処理と、基板表面に薄膜を成膜する成膜処理について説明したが、本発明の真空処理方法はこれに限られるものではなく、真空雰囲気中で基板を静電吸着した状態で、基板を処理する方法であれば、いかなる方法にも適用可能である。
【００８６】
また、本実施形態では、基板としてソーダ石灰ガラス基板を用いたが、本発明の真空処理方法で静電吸着可能な基板はこれに限られるものではなく、例えばプラスチックや、シリコン酸化物や、窒化珪素等からなる基板のように、絶縁性を有する基板であればいかなる基板の静電吸着にも適用可能である。
また、本発明の方法は、シリコン等の半導体基板の静電吸着においても、吸着力を適正に制御し、かつ残留吸着力を抑制する方法として有効である。
【００８７】
【発明の効果】
静電吸着された基板を短時間で静電吸着装置から離脱させることができる。また、静電吸着装置用の電源を高圧出力の電源で構成する必要がないので、装置のコストを低減でき、放電等による装置の故障を抑止することができる。
【図面の簡単な説明】
【図１】本発明に係る真空処理方法を実施する真空処理装置の一例を示す概略構成図
【図２】（ａ）：本発明の真空処理方法に用いる静電吸着装置の構成を説明する断面図
（ｂ）：本発明の真空処理方法に用いる静電吸着装置の構成を説明する平面図
【図３】本発明の真空処理方法を説明する第１の図
【図４】本発明の真空処理方法を説明する第２の図
【図５】本発明の真空処理方法を説明する第３の図
【図６】本発明の真空処理方法を説明する第４の図
【図７】本発明の真空処理方法を説明する第５の図
【図８】本発明の真空処理方法を説明する第６の図
【図９】本発明の真空処理方法を説明する第７の図
【図１０】本発明の真空処理方法において、電極に印加する電圧の時間変化及び吸着力の時間変化を説明する第１のグラフ
【図１１】本発明の真空処理方法において、電極に印加する電圧の時間変化及び吸着力の時間変化を説明する第２のグラフ
【図１２】本発明の真空処理方法において、電極に印加する電圧の時間変化及び吸着力の時間変化を説明する第３のグラフ
【図１３】本発明の真空処理方法において、電極に印加する電圧の時間変化及び吸着力の時間変化を説明する第４のグラフ
【図１４】（ａ）：従来の真空処理方法を説明する第１の図
（ｂ）：従来の真空処理方法を説明する第２の図
（ｃ）：従来の真空処理方法を説明する第３の図
【図１５】（ｄ）：従来の真空処理方法を説明する第４の図
（ｅ）：従来の真空処理方法を説明する第５の図
（ｆ）：従来の真空処理方法を説明する第６の図
【図１６】従来の真空処理方法において、電極に印加する電圧の時間変化及び吸着力の時間変化を説明する第１のグラフ
【図１７】従来の真空処理方法において、電極に印加する電圧の時間変化及び吸着力の時間変化を説明する第２のグラフ
【符号の説明】
１…真空処理装置 ２…搬出入室 ３…搬送室 ４…処理室 １３…静電吸着装置 ４０…静電チャックプレート(静電吸着装置) ５０…基板[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a vacuum processing method in which a substrate is processed in a vacuum atmosphere while being attracted and held by an electrostatic adsorption device, and in particular, in a conveyance process of conveying a substrate in a state in which the substrate is electrostatically adsorbed by an electrostatic adsorption device. The present invention relates to a technique for shortening the time until the substrate is separated from the electrostatic chuck after being transported.
[0002]
[Prior art]
In recent years, in an apparatus that performs processing such as film formation on a substrate made of glass or the like, an electrostatic attracting apparatus that attracts and holds the substrate by electrostatic force is widely used. As such an electrostatic adsorption device, a device integrated with a hot plate capable of temperature control (heating or cooling) to maintain the substrate at a predetermined temperature in processing such as film formation, or the substrate is transported. A device that is provided at the tip of a transfer robot and that can be transferred in a state where a substrate is electrostatically attracted is known.
[0003]
Among these, the electrostatic attraction apparatus used for the substrate transfer apparatus will be described below.
Reference numeral 110 in FIG. 14 shows a substrate transfer apparatus provided with such an electrostatic chuck.
The substrate transfer device 110 includes a drive mechanism 111, an arm 112, and an electrostatic adsorption device 113. One end of the arm 112 is attached to the drive mechanism 111, and the arm 112 is configured to move in the horizontal plane and in the vertical direction when the drive mechanism 111 is driven. An electrostatic adsorption device 113 is attached to the tip of the arm 112, and is configured such that when the arm 112 is moved, the electrostatic adsorption device 113 can be freely moved in the horizontal plane and in the vertical direction.
[0004]
The electrostatic adsorption device 113 is composed of a dielectric plate, and has first and second adsorption electrodes 143 and 144 inside. These first and second suction electrodes 143 and 144 are connected to an electrostatic suction power source (not shown), and when the electrostatic suction power source is activated, the first and second suction electrodes 143 and 144 are A DC voltage can be applied.
[0005]
The operation of moving a glass substrate placed on one placement table in a vacuum atmosphere using such a substrate transfer device 110 onto another placement table will be described below. Hereinafter, it is assumed that the mounting table, the substrate transfer device, and the substrate are all arranged in a vacuum atmosphere.
[0006]
First, as shown in FIG. 14 (a), the arm 112 is moved horizontally, and the electrostatic chuck 113 is placed on the surface of a mounting table (hereinafter referred to as a moving mounting table) 105, soda-lime glass. The substrate 150 is moved upward. Next, the arm 112 is lowered, and the surface of the electrostatic chuck 113 is brought into contact with the surface of the substrate 150 as shown in FIG.
[0007]
Next, when a voltage is applied between the first and second attracting electrodes 143 and 144, an electrostatic attracting force is generated between the substrate 150 and the electrostatic attracting device 113. This electrostatic attraction force increases as the application time of the voltage applied between the first and second attraction electrodes 143 and 144 becomes longer. Even if the electrostatic adsorption device 113 moves while holding the substrate 150 downward, when the electrostatic adsorption force becomes large enough to prevent the substrate 150 from dropping, the arm 112 is raised to raise the electrostatic adsorption device 113. To raise. Then, as shown in FIG. 14 (c), the substrate 150 is lifted away from the movement source mounting table 105 together with the electrostatic chuck 113 while being held by the electrostatic chuck 113. .
[0008]
Next, the arm 112 is moved horizontally to move the electrostatic adsorption device 113 horizontally, and as shown in FIG. 15D, the electrostatic adsorption device 113 is placed on the mounting table 106 (hereinafter referred to as the mounting table 106) on which the substrate 150 is to be placed. Move to the rest and place it stationary. Next, the arm 112 is lowered and the electrostatic chuck 113 is lowered. As shown in FIG. 15E, when the substrate 150 comes into contact with the surface of the mounting table 106, the electrostatic chuck 113 is stopped.
[0009]
Thereafter, application of voltage between the first and second adsorption electrodes 143 and 144 is stopped. Then, the electrostatic attraction force generated between the substrate 150 and the electrostatic attraction device 113 decreases. When the electrostatic adsorption force is sufficiently reduced, the electrostatic adsorption device 113 cannot adsorb and hold the substrate 150. When the electrostatic attraction force is nearly zero, the electrostatic attraction device 113 is raised. Then, as shown in FIG. 15 (f), the electrostatic chuck 113 is separated from the substrate 150, and as a result, the substrate 150 is mounted on the mounting table 106 at the movement destination. Through the above operation, the substrate 150 is transported from the source mounting table 105 to the destination mounting table 106.
[0010]
FIG. 16 shows the time change of the voltage applied between the first and second suction electrodes 143 and 144 and the electrostatic suction force between the substrate 150 and the electrostatic suction device 113. A curve (V) in FIG. 15 shows a change over time in the voltage applied between the first and second adsorption electrodes, and the curve (W) is generated between the substrate 150 and the electrostatic adsorption device 113. The time change of electrostatic attraction force is shown.
[0011]
In the figure, reference numeral f ₁ Indicates the minimum force (hereinafter referred to as the minimum adsorption force) that can be safely moved while the electrostatic adsorption device 113 holds the substrate 150 by electrostatic adsorption.
Symbol t ₁ Indicates the time at which application of a voltage is started between the first and second adsorption electrodes 143 and 144. The symbol t ₂ The electrostatic attraction force is the minimum attraction force f ₁ The time when the electrostatic attraction device 113 has reached the above and started to move in a state where the electrostatic suction device 113 sucks and holds the substrate 150 is shown, and the symbol t _Three Indicates the time when the electrostatic chuck 113 is moved while the substrate 150 is held.
[0012]
The symbol t _Five Indicates the time when the application of the voltage between the first and second adsorption electrodes 143 and 144 is terminated, and the symbol t ₆ Indicates the time when the electrostatic chuck 113 releases the holding of the substrate 150 and releases the substrate 150.
[0013]
In the transfer process described above, as shown by the curve (V) in FIG. ₁ The time t when the application of the voltage between the first and second adsorption electrodes 143 and 144 is started and the movement is completed after the substrate 150 is placed on the placement platform 106. _Three After the time t _Five Until the constant voltage V between the first and second adsorption electrodes 143 and 144 is reached. ₁ Is continuing to be applied.
[0014]
For this reason, as shown by the curve (W), the electrostatic attraction force is the time t when the application of the voltage between the first and second attraction electrodes 143 and 144 ends. _Five The electrostatic adsorption force continues to rise to the minimum adsorption force f ₁ Greatly exceeded. Time t when application of voltage between the first and second adsorption electrodes 143 and 144 ends _Five Thereafter, the electrostatic attractive force gradually decreases, but the electrostatic attractive force is the minimum attractive force f. ₁ And a large amount of residual charge remains between the substrate 150 and the electrostatic adsorption device 113, and this residual charge leaves an adsorption force. Therefore, it takes a long time for the adsorption force to decrease to such an extent that the substrate can be detached. It takes time (for example, several minutes or more).
[0015]
For this reason, immediately after the application of the voltage between the first and second adsorption electrodes 143 and 144 is finished, the voltage applied between the first and second adsorption electrodes 143 and 144 is opposite to that immediately before. The inventors of the present invention proposed a technique for detaching the substrate from the electrostatic attraction apparatus in a short time by applying a polar voltage for a short period of time to eliminate residual charges and setting the electrostatic attraction force to 0. . In curves (X) and (Y) of FIG. 17, the time change of the voltage applied between the first and second suction electrodes in that case and the electrostatic force generated between the substrate 150 and the electrostatic suction device 113 are shown. The time change of the adsorption force is shown respectively.
[0016]
According to this method, as shown by the curve (X) in FIG. _Five To time t _a The voltage V applied until just before between the first and second adsorption electrodes 143 and 144 during the period until ₁ And reverse polarity voltage V ₀ Is applied. During this period, as indicated by the curve (Y) in the figure, the electrostatic attractive force decreases rapidly and approaches 0 in a short time. ₀ Compared with the case where no is applied, the time until the substrate can be detached can be greatly reduced.
[0017]
However, in order to eliminate the residual charge in a short time and make the adsorption force zero, the reverse polarity voltage V ₀ The voltage V applied until just before applying ₁ It is necessary to apply a reverse polarity voltage whose absolute value is larger than the predetermined time.
[0018]
The inventors of the present invention applied voltages of +3000 V and −3000 V to the first and second adsorption electrodes 143 and 144, respectively, and electrostatically adsorbed a substrate made of soda-lime glass to the electrostatic adsorption device 113 for 60 seconds. Thereafter, in order to be able to safely remove the substrate 10 seconds after the completion of the suction, high voltages of −5000V and + 5000V must be applied to the first and second suction electrodes 143 and 144 for 10 seconds, respectively. I confirmed that.
[0019]
Thus, in order to apply a high-voltage reverse polarity voltage between the first and second adsorption electrodes 143 and 144, a high-voltage output power source is required, which increases the cost of the entire apparatus. In addition, since the electrostatic adsorption power supply becomes high voltage, discharge between the electrostatic adsorption device and its peripheral devices, discharge between the first and second adsorption electrodes, etc. occur, and the device breaks down due to such discharge. There were also problems such as being easy to do.
[0020]
[Problems to be solved by the invention]
The present invention was created to solve the above-described disadvantages of the prior art, and in particular, when holding a substrate by electrostatic attraction, the electrostatic attraction power source is not used as a high-voltage output power source and for a short time. It is to provide a technique that enables the substrate to be detached.
[0021]
[Means for Solving the Problems]
In order to solve the above-mentioned problem, the invention described in claim 1 is a vacuum processing method for performing processing by electrostatically attracting a substrate in a vacuum, wherein the substrate can be moved by being electrostatically attracted and suspended. First, an adsorption force is obtained in advance, the substrate is brought into contact with an electrostatic adsorption device, and an adsorption force greater than the minimum adsorption force is generated between two electrodes disposed in the electrostatic adsorption device. After the substrate is lifted with an adsorption force equal to or greater than the minimum adsorption force, a voltage to be applied between the two electrodes is applied to the electrostatic adsorption between the electrostatic adsorption device and the substrate. Change to the second voltage to decrease the force Decrease the suction force while moving the substrate The vacuum processing method of ending the movement of the substrate while the electrostatic adsorption force between the electrostatic adsorption device and the substrate is equal to or greater than the minimum adsorption force.
Invention of Claim 2 is the vacuum processing method of Claim 1, Comprising: The process of changing the voltage applied between the said electrodes to the said 2nd voltage, and reducing the said electrostatic attraction force, After the first voltage is applied, the electrostatic attraction force is performed before the upper limit attraction force greater than the minimum attraction force.
The invention described in claim 3 is the vacuum processing method according to claim 1 or 2, wherein voltages having different polarities are applied between the electrodes.
Invention of Claim 4 is the vacuum processing method of Claim 3, Comprising: In the process of changing the voltage applied between the said electrodes to the said 2nd voltage, and reducing the said electrostatic attraction force, The potential difference between the two electrodes is made smaller than the potential difference between the two electrodes in the step of applying the first voltage.
Invention of Claim 5 is the vacuum processing method of Claim 3, Comprising: In the process of changing the voltage applied between the said electrodes to the said 2nd voltage, and reducing the said electrostatic attraction force, The potential difference between the two electrodes is set to 0 volts.
Invention of Claim 6 is the vacuum processing method of Claim 3, Comprising: In the process of changing the voltage applied between the said electrodes to the said 2nd voltage, and reducing the said electrostatic attraction force, In the step of applying the first voltage, a voltage having a reverse polarity to the voltage applied between the two electrodes is applied between the two electrodes.
A seventh aspect of the present invention is the vacuum processing method according to the third aspect, wherein the voltage applied between the electrodes is changed to the second voltage to reduce the electrostatic attraction force. A voltage at which a potential difference between the two electrodes changes stepwise is applied to the two electrodes.
[0022]
The inventors of the present invention have conducted research on the relationship between the electrostatic adsorption force between the electrostatic adsorption device and the substrate, the voltage applied to the adsorption electrode, and the application time.
The inventors of the present invention have a density of 2.47 g / cm. ^Three A substrate made of soda-lime glass plate having a thickness of 3 mm is brought into contact with an electrostatic adsorption device having two adsorption electrodes, and a fixed voltage is applied to each of the two adsorption electrodes (here, two adsorption electrodes And + 3000V and -3000V, respectively), an experiment for examining the time dependency of the electrostatic adsorption force generated between the electrostatic adsorption device and the substrate, and a constant voltage (here Then, +3000 V and -3000 V are applied to the two adsorption electrodes, respectively) for 60 seconds to electrostatically adsorb the substrate, the voltage applied to each adsorption electrode is set to 0 V, and after that time the substrate and An experiment was conducted to investigate the time dependence of the electrostatic adsorption force (hereinafter referred to as the residual adsorption force) remaining between the electrostatic adsorption devices. The results of the two types of experiments are shown in Table 1 below.
[0023]
[Table 1]

[0024]
From the time dependency of the electrostatic attraction force shown in Table 1 above, the attraction force after 5 seconds from the start of voltage application to the attraction electrode is 4.50 gf / cm. ² It has become. When the thickness of the substrate used in this experiment is 1 cm, the adsorption force balanced with the weight of the substrate is 2.47 gf / cm. ² Therefore, to lift a 3mm thick substrate, 3gf / cm ² It is sufficient if there is a degree of adsorption power. That is, the minimum adsorption force here is 3 gf / cm. ² It is. From this, it can be seen that the substrate can be electrostatically attracted and lifted after 5 seconds have elapsed since the start of voltage application to the attracting electrode.
[0025]
However, looking at the time dependence of the residual adsorption force after applying a voltage to the adsorption electrode for 60 seconds, the residual adsorption force is 31 gf / cm when 60 seconds have elapsed from the time when the voltage application is completed. ² It has decreased only until. In order to safely detach the substrate, the residual adsorption force is equal to the above-mentioned minimum adsorption force (here 3 gf / cm ² ) Of about 80% of adsorption force (in this case, 2.4 gf / cm ² ) It is necessary to decrease to the following, but the residual adsorption force is 25.5 gf / cm even after 600 seconds. ² Therefore, the substrate cannot be safely removed. In this way, after a single substrate is adsorbed for 60 seconds, the substrate cannot be detached even if 600 seconds or more have passed.
[0026]
Using the same substrate and the same electrostatic adsorption apparatus as those used in Table 1 above, the voltage applied to the adsorption electrode is low (here, +750 V and -750 V are applied to the two adsorption electrodes, respectively). The same experiment was conducted. Table 2 below shows the results of an experiment examining the time dependence of the electrostatic adsorption force generated between the electrostatic adsorption device and the substrate in that case, and the substrate was applied by applying a voltage to the adsorption electrode for 60 seconds. After electrostatic attraction, 0 V is applied to each attraction electrode, and the results of an experiment for examining the time dependence of the residual attraction force remaining between the substrate and the electrostatic attraction apparatus after that time are shown.
[0027]
[Table 2]

[0028]
From the time dependency of the electrostatic adsorption force shown in Table 2 above, the adsorption force is the minimum adsorption force (here 3 gf / cm ² It can be seen that 10 seconds from the start of voltage application is not enough to increase the above, and that it becomes greater than the minimum adsorption force at a certain time between 10 seconds and 60 seconds. The adsorption force after 5 seconds from the start of voltage application is 0.2 gf / cm ² It can be seen that it is impossible to lift the substrate.
[0029]
Moreover, although the residual adsorption force after electrostatic adsorption for 60 seconds is small, 2.7 gf / cm when 60 seconds elapse after the voltage application is stopped. ² The suction force (in this case, 2.4 gf / cm) that can be safely removed from the substrate by the electrostatic suction device ² ) Will not drop.
[0030]
As described above, if the same high voltage is continuously applied to the suction electrode, it is possible to suck and hold the substrate in a relatively short time, but the suction force becomes excessive, and then the substrate is detached. On the other hand, if the same low voltage is continuously applied to the adsorption electrode, the residual adsorption force does not increase excessively, but the adsorption is sufficient to hold the substrate. It has been found that it takes a long time to reach the force, and the time required for the residual attracting force to safely remove the substrate from the electrostatic attracting apparatus is not so short.
[0031]
Considering the above results, the inventors of the present invention applied a high voltage to the adsorption electrode for a predetermined time from the start of voltage application to increase the adsorption force, and then applied the voltage to the adsorption electrode while adsorbing the substrate. If the adsorption force is reduced by changing the above, the adsorption force will not be excessively increased. Therefore, it is assumed that the substrate can be detached in a short time after adsorbing the substrate in a short time.
[0032]
In order to confirm this assumption, the inventors of the present invention applied the same substrate and electrostatic chuck as those used in the experiments shown in Table 1 and applied a high voltage to each chucking electrode for 5 seconds ( Here, + 3000V and -3000V are applied to the two adsorption electrodes, respectively), and the applied voltage is set to a low voltage (here, + 750V and -750V are applied to the two adsorption electrodes, respectively). An experiment for examining the time dependency of the adsorption force, and after applying a voltage to the adsorption electrode for a total of 60 seconds under the same conditions as the experiment, the voltage applied to each adsorption electrode is set to 0 V, and the residual adsorption force generated after the time of setting the voltage to 0 V We conducted experiments to investigate the time dependence of. The results of these experiments are shown in Table 3 below.
[0033]
[Table 3]

[0034]
From the time dependency of the adsorption force shown in Table 3 above, the adsorption force is 4.5 gf / cm when 5 seconds have elapsed from the start of voltage application. ² It is possible to adsorb and hold the substrate, and even after 60 seconds, the adsorption force is 4.9 gf / cm. ² It can be seen that it is above the minimum adsorption force and maintains a size that can sufficiently adsorb and hold the substrate.
[0035]
Further, from the time dependence of the residual adsorption force shown in Table 3, the residual adsorption force at the time when the voltage application to the adsorption electrode is finished is 4.9 gf / cm. ² However, the residual adsorptive power at the time when 60 seconds have elapsed after the voltage application is finished is 3.1 gf / cm. ² It can be seen that the residual adsorptive power is considerably smaller than when a constant voltage is continuously applied.
[0036]
In this way, first, a high voltage that increases the suction force is applied to the suction electrode, and after the substrate is sucked and held in a short time, the voltage applied to the suction electrode is decreased while the substrate is sucked and held. It was confirmed that by reducing the adsorption force, the substrate can be adsorbed and held in a short time, and the substrate can be detached in a short time.
[0037]
The present invention has been created based on such knowledge, and is applied to an electrode after applying a first voltage to an electrode in the electrostatic adsorption device while the substrate is in contact with the electrostatic adsorption device. The voltage to be changed is changed to the second voltage.
[0038]
At this time, for the substrate to be processed, a minimum suction force that is a minimum value of the force capable of electrostatically attracting the substrate is obtained in advance, and the magnitudes of the first and second voltages are determined according to the time for processing the substrate. Appropriate values are obtained for the application time, the substrate processing start time, and the end time. In accordance with the appropriate value thus obtained, the first voltage is applied to the electrode so that the electrostatic attraction force is greater than the minimum attraction force, and the substrate is processed after electrostatic attraction to the electrostatic attraction device. When the voltage applied to the electrode during the processing of the substrate is changed to the second voltage, the electrostatic attraction force decreases after the change to the second voltage and the processing of the substrate is completed. The substrate can be kept electrostatically attracted to the electrostatic attracting device while maintaining the electrostatic attracting force to be equal to or greater than the minimum attracting force.
[0039]
With this configuration, at the time when the processing of the substrate is completed, the amount of residual charge is reduced compared to the conventional case where the same voltage is applied to the electrode, and the residual attractive force is reduced. The time required for removing the substrate from the apparatus can be shortened as compared with the conventional case.
[0040]
In particular, when a voltage having a reverse polarity is applied to the electrode to eliminate the residual charge in a short time and the adsorption force is set to 0, the second voltage applied until immediately before the voltage having the reverse polarity is applied is applied. Even if a voltage having a small absolute value is applied, residual charges can be eliminated in a short time. Therefore, since a high-voltage output electrostatic adsorption power supply is not required as in the prior art, the overall cost of the apparatus does not increase, and the discharge between the electrostatic adsorption apparatus and its peripheral devices and between the adsorption electrodes Failures are less likely to occur due to discharge or the like.
[0041]
In the present invention, the voltage applied to the electrode may be changed to the second voltage before the electrostatic attraction force exceeds the upper limit attraction force larger than the minimum attraction force.
Here, the upper limit adsorption force means that, while the substrate is processed in a state of being electrostatically adsorbed to the electrostatic adsorption device, the adsorption force is maintained above the minimum adsorption force, and after the processing is completed, the substrate is transferred from the electrostatic adsorption device. Is the upper limit of the adsorption force that can be reduced to a force sufficient to safely release the. This upper limit attracting force is determined according to the voltage applied to the electrode in the electrostatic attracting apparatus and the processing time of the substrate. If the attracting force exceeds the upper limit attracting force, after the processing of the substrate is finished, the residual attracting force Becomes excessive, and the substrate cannot be safely detached from the electrostatic chuck.
[0042]
Before the upper limit attracting force exceeds the upper limit attracting force, the voltage applied to the electrode is changed to the second voltage, and the attracting force is decreased. Since it is lowered to such an extent that the substrate can be safely removed from the adsorption device, the substrate can be safely removed immediately after the processing is completed.
[0043]
In the present invention, the electrode of the electrostatic adsorption device is composed of two electrodes. When the first or second voltage is applied to the electrodes, voltages having different polarities are applied to the electrodes. You may comprise. In that case, in the step of changing the voltage applied to the electrode to the second voltage and reducing the electrostatic attraction force, the potential difference between the two electrodes is divided into two in the step where the first voltage is applied. It may be configured to be smaller than the potential difference between the electrodes. By configuring in this way, the attractive force after changing to the second voltage becomes smaller than the voltage when the first voltage is applied.
[0044]
Further, in the step of changing the voltage applied to the electrode to the second voltage to reduce the electrostatic adsorption force, the potential difference between the two electrodes may be configured to be 0 volt, Further, in the step of applying the first voltage, a voltage having a reverse polarity to the voltage applied to the two electrodes may be applied to the two electrodes. By comprising in this way, the amount of reduction of the electrostatic attraction force after applying the second voltage can be increased.
[0045]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below with reference to the drawings. Reference numeral 1 in FIG. 1 indicates a vacuum processing apparatus used in the vacuum processing method of the present invention.
The vacuum processing apparatus 1 has a carry-in / out chamber 2, a transfer chamber 3, and a processing chamber 4. The evacuation systems 72, 73, and 74 are connected to the carry-in / out chamber 2, the transfer chamber 3, and the processing chamber 4, and when these evacuation systems 72, 73, and 74 are activated, The inside of the transfer chamber 3 and the processing chamber 4 can be evacuated.
[0046]
A transfer robot 10 is disposed inside the transfer chamber 3. The transfer robot 10 includes a drive mechanism 11, an arm 12, and an electrostatic adsorption device 13.
The drive mechanism 11 is disposed on the inner bottom surface of the transfer chamber 3.
[0047]
One end of the arm 12 is attached to the tip of the drive mechanism 11, and is configured to be freely movable in a horizontal plane when the drive mechanism 11 is operated. An electrostatic adsorption device 13 is disposed at the tip of the arm 12.
[0048]
The configuration of the electrostatic adsorption device 13 is shown in FIGS. 2 (a) and 2 (b). The electrostatic adsorption device 13 includes a metal plate 24 and a dielectric layer 25 disposed on the metal plate 24. The dielectric layer 25 is made of Al. ₂ O _Three The first and second adsorption electrodes 27 made of Al are formed on the surface of the ceramic. ₁ , 27 ₂ Is formed.
[0049]
First and second adsorption electrodes 27 ₁ , 27 ₂ A plan view is shown in FIG. First and second adsorption electrodes 27 ₁ , 27 ₂ Is shaped like a comb and is arranged so that its tooth portions mesh with each other. The figure (a) is equivalent to the XX sectional view of the figure (b). First and second adsorption electrodes 27 ₁ , 27 ₂ The width of the electrode is 4 mm, the distance between the electrodes is 1 mm, and the thickness of the electrodes is 10 μm.
[0050]
Such an electrostatic adsorption device 13 includes first and second adsorption electrodes 27. ₁ , 27 ₂ When the arm 12 moves in a horizontal plane, the first and second adsorption electrodes 27 are attached so that the surface on which the is disposed faces vertically downward. ₁ , 27 ₂ It is configured so that it can move freely in the horizontal plane together with the arm 12 in a state where the surface on which the is arranged faces vertically downward.
[0051]
First and second adsorption electrodes 27 ₁ , 27 ₂ Are connected to an electrostatic attraction power source 15 provided outside the transfer chamber 3, and when the electrostatic attraction power source 15 is driven, the first and second attraction electrodes 27 are connected. ₁ , 27 ₂ It is comprised so that a DC voltage can be applied between.
[0052]
A substrate transfer process for transferring a substrate from the loading / unloading chamber 2 to the processing chamber 4 using the vacuum processing apparatus 1 having the above-described configuration will be described below.
As shown in FIG. 3, the internal atmospheres of the carry-in / out chamber 2, the transfer chamber 3, and the processing chamber 4 are each evacuated independently, and in this state, the drive mechanism 11 is operated to move the arm 12 horizontally, The electrostatic adsorption device 13 is carried into the carry-in / out chamber 2 and is placed above the substrate 50 placed on the surface of the mounting table 6 in the carry-in / out chamber 2 to be stationary.
[0053]
Next, as shown in FIG. 4, the surface of the substrate 50 is brought into contact with the surface of the electrostatic adsorption device 13. Here, the surface of the substrate 50 is brought into contact with the surface of the electrostatic adsorption device 13 by placing the substrate 50 on the elevating pins 60 and moving the substrate 50 upward by raising the elevating pins 60.
[0054]
Next, the electrostatic attraction power source 15 is activated, and the first and second attraction electrodes 27 of the electrostatic attraction apparatus 13. ₁ , 27 ₂ A predetermined first voltage is applied between them. (Here, the first and second adsorption electrodes 27 ₁ , 27 ₂ Are applied with + 3000V and -3000V, respectively). Then, an electrostatic adsorption force is generated between the electrostatic adsorption device 13 and the substrate 50. This electrostatic attraction force increases according to the voltage application time. When the electrostatic attraction force increases and becomes equal to or greater than the minimum value of the force that can be safely moved by the electrostatic attraction device 13 while electrostatically attracting the substrate 50 (hereinafter referred to as the minimum attraction force), the substrate 50. Is adsorbed and held on the surface of the electrostatic adsorption device 13. The state is shown in FIG. When sucked and held, the elevating pin 60 is lowered and stored in the mounting table 6.
[0055]
Next, the arm 12 is moved horizontally, and the electrostatic chuck 13 is moved from the loading / unloading chamber 2 to the transfer chamber 3 with the substrate 50 being sucked, and is loaded into the processing chamber 4. During this movement, the first and second adsorption electrodes 27 of the electrostatic adsorption device 13 are used. ₁ , 27 ₂ Is applied to the second voltage (here, the first and second adsorption electrodes 27). ₁ , 27 ₂ To + 750V and -750V, respectively). Specifically, the applied voltage is changed to the second voltage after 5 seconds have elapsed since the application of the first voltage was started. After changing to the second voltage, the electrostatic attraction force decreases, but the substrate 50 is still held in an electrostatic attraction state by the electrostatic attraction device 13.
[0056]
A mounting table 48 is disposed on the inner bottom surface of the processing chamber 4, and an electrostatic chuck plate 40 described in detail later is disposed on the mounting table 48. When the electrostatic chuck 13 is located at a predetermined position above the electrostatic chuck plate 40, the electrostatic chuck 13 is stopped. The state is shown in FIG.
[0057]
Inside the mounting table 48 and the electrostatic chuck plate 40, raising and lowering pins that can be moved up and down through these are arranged. When the electrostatic chuck 13 is stationary at the upper position of the electrostatic chuck plate 40, the lifting pins 61 are raised as shown in FIG. 7 so as to contact the surface of the substrate 50 held downward below the electrostatic chuck 13. Make contact.
[0058]
After that, the first and second adsorption electrodes 27 ₁ , 27 ₂ In addition, a predetermined voltage having a polarity opposite to that of the second voltage applied until immediately before is applied. Specifically, −300 V and +300 V are applied to the first and second adsorption electrodes 27. ₁ , 27 ₂ Respectively.
[0059]
When a voltage having a reverse polarity is applied in this way, the residual charge between the substrate 50 and the electrostatic adsorption device 13 is rapidly reduced and disappears, the electrostatic adsorption force becomes almost zero, and the substrate 50 is electrostatically adsorbed. The device 13 can be easily detached from the device 13. In this state, when the elevating pins 61 are lowered, the substrate 50 is detached from the electrostatic attraction device 13, is placed on the upper ends of the elevating pins 61, and is lowered together with the elevating pins 61. When the elevating pins 61 are completely accommodated in the mounting table 48, the substrate 50 is mounted on the surface of the electrostatic chuck plate 40. The state is shown in FIG. Through the above steps, the transfer process of the substrate 50 from the loading / unloading chamber 2 to the processing chamber 4 is completed.
[0060]
FIG. 10 shows the first and second adsorption electrodes 27 in the substrate transfer process described above. ₁ , 27 ₂ The voltage applied in between and the time change of the electrostatic attraction force between the board | substrate 50 and the electrostatic attraction apparatus 13 are shown. The curve (A) in FIG. 10 shows the first and second adsorption electrodes 27. ₁ , 27 ₂ The time change of the voltage applied between them is shown (for the sake of simplicity, the first adsorption electrode 27 is shown. ₁ The voltage is shown. ) And curve (B) show the time change of the electrostatic adsorption force generated between the substrate 50 and the electrostatic adsorption device 13.
[0061]
In the figure, reference sign V ₁ Are the first and second adsorption electrodes 27. ₁ , 27 ₂ The first voltage applied first in the meantime (here, the first and second adsorption electrodes 27) ₁ , 27 ₂ Are applied with + 3000V and -3000V, respectively). ₂ Is the first voltage V ₁ Is applied for a predetermined time (here, 5 seconds), and then the first and second adsorption electrodes 27 are applied. ₁ , 27 ₂ A second voltage applied between them (here, the first and second adsorption electrodes 27). ₁ , 27 ₂ Are applied with +750 V and -750 V, respectively). Also, the symbol f ₁ Indicates the minimum adsorption force.
[0062]
The symbol t ₁ Are the first and second adsorption electrodes 27. ₁ , 27 ₂ The time at which the application of voltage is started is shown, and the symbol t ₂ Indicates the time when the electrostatic chuck 13 starts moving. The symbol t _Three Indicates the time when the movement of the electrostatic chuck 13 with the substrate 50 being sucked is completed, and the time t _h Applies the applied voltage to the first voltage V ₁ To the second voltage V ₂ Indicates the time of change to. The symbol t _Four Are the first and second adsorption electrodes 27. ₁ , 27 ₂ In the meantime, the second voltage V applied immediately before ₂ And the time when the reverse polarity voltage starts to be applied, _Five Indicates the time when the application of the reverse polarity voltage is finished, and the time t ₆ Indicates the time when the substrate 50 is detached from the electrostatic chuck 13.
[0063]
In the substrate transfer process described above, as shown by the curve (A) in FIG. ₂ At the time t _Three At time t (60 seconds here) _h The first and second adsorption electrodes 27 ₁ , 27 ₂ The voltage applied between the first voltage V ₁ To the second voltage V ₂ It has changed to.
[0064]
Preliminary minimum adsorption force f ₁ And these first and second voltages V _1, V ₂ The voltage value and the application time are set to appropriate values. As a result, the applied voltage is set to the second voltage V. ₂ Time t changed to _h Thereafter, the adsorption force decreases, but the time t when the movement ends. _Three In the meantime, as shown in the curve (B), the adsorption force is the minimum adsorption force f. ₁ The values are as described above, and the substrate 50 is prevented from dropping from the electrostatic adsorption device 13 until the movement is completed (60 seconds) after the substrate 50 is attracted and moved.
[0065]
Further, since the suction force decreases during the movement of the substrate, the suction force does not increase excessively, and the time t when the movement is finished. _Three The adsorbing force at is smaller than that of the prior art. Therefore, after the movement is finished, the time t _Four ~ T _Five Between the first and second adsorption electrodes 27 during this period (here 2 seconds) ₁ , 27 ₂ Even when the residual charge is extinguished in a short time by applying in between, it is not necessary to apply a voltage having a larger absolute value than the voltage applied until just before, and it was applied until just before. Second voltage V ₂ A lower voltage is applied (here, the first and second adsorption electrodes 27). ₁ , 27 ₂ In this case, the attracting force is almost zero in a short time, and the substrate 50 can be easily detached from the electrostatic attracting device 13.
[0066]
Accordingly, since it is not necessary to configure the electrostatic attraction power source 15 with a high-voltage output power source, the cost of the electrostatic attraction power source 15 can be reduced, and the cost of the entire apparatus can be reduced. In addition, a discharge occurs between the electrostatic adsorption device 13 and its peripheral devices, or the first and second adsorption electrodes 27. ₁ , 27 ₂ As a result of the discharge occurring between the two, there is no possibility that the apparatus will fail.
[0067]
In the above-described substrate transfer process, as shown in FIG. ₂ To the first voltage V ₁ With the same polarity as the first voltage V ₁ Lower voltage, then reverse polarity voltage V _Three The first and second adsorption electrodes 27 ₁ , 27 ₂ However, the substrate transfer process of the present invention is not limited to this. For example, as shown in the curve (C) of FIG. ₂ To the first voltage V ₁ With the same polarity as the first voltage V ₁ (Here, the first and second adsorption electrodes 27 ₁ , 27 ₂ Are applied with + 3000V and -3000V respectively). ₂ (Here, the first and second adsorption electrodes 27 ₁ , 27 ₂ And + 950V and -950V, respectively, are applied), and the voltage may be lowered stepwise. Here, the voltage (V in FIG. _Four ~ V ₆ ), The reverse polarity voltage V _Three The first and second adsorption electrodes 27 ₁ , 27 ₂ Applied between.
[0068]
The first and second voltages V are configured in this way in advance. ₁ , V ₂ By setting the voltage value, the application time, the movement start time, and the movement end time to appropriate values, the electrostatic adsorption device 13 as shown in the curve (D) of FIG. Movement end time t _Three Until the adsorption force is the minimum adsorption force f ₁ As described above, it is possible to prevent the substrate 50 from dropping from the electrostatic adsorption device 13 during movement. Also, the adsorption force does not increase excessively, and the symbol f in the figure ₂ It does not exceed the upper limit adsorption force shown in. Therefore, time t _Four The reverse polarity voltage is applied to the first and second adsorption electrodes 27. ₁ , 27 ₂ Even when a short period of time is applied and the residual charge disappears in a short time, the second voltage V ₂ The following voltages are applied (here, the first and second adsorption electrodes 27) ₁ , 27 ₂ (-300V and + 300V are applied respectively), the residual charges are extinguished, the attracting force is almost zero, and the substrate 50 can be easily detached from the electrostatic attracting device 13.
[0069]
Also, the first and second adsorption electrodes 27 ₁ , 27 ₂ 0V is applied to both, and the second voltage V as shown in the curve (E) of FIG. ₂ May be configured to be 0V. With this configuration, as shown in the curve (F) in FIG. ₂ Time t changed to _h Thereafter, the adsorption force can be reduced in a short period of time.
[0070]
Furthermore, as shown in the curve (G) of FIG. ₂ As the first voltage V ₁ The first and second adsorption electrodes 27 are applied with voltages of opposite polarities. ₁ , 27 ₂ You may apply between. With this configuration, the second voltage V shown in FIG. ₂ As compared with the case where the voltage is set to 0 V, as shown by the curve (H) in FIG.
[0071]
In the above-described embodiment, the second voltage V ₂ However, the present invention is not limited to this, but the first and second voltages V3 are applied. ₁ , V ₂ By setting the voltage value and application time value to appropriate values, the reverse polarity voltage V _Three It is also possible to configure so that the residual charge disappears in a short time without applying.
[0072]
When the substrate transfer process described above is completed and the substrate 50 is placed on the surface of the electrostatic chuck plate 40, the arm 12 is moved horizontally to retract the electrostatic chuck 13 and the arm 12 into the transfer chamber 3. Thereafter, the valve 8 disposed inside the processing chamber 4 is closed, the processing chamber 4 is shut off from the inside of the transfer chamber 3, and the film forming process is started. The state is shown in FIG.
[0073]
The electrostatic chuck plate 40 is made of a dielectric plate made of, for example, a ceramic material. In the electrostatic chuck plate 40, first and second adsorption electrodes 43 and 44 made of a conductive material are arranged.
[0074]
The first and second suction electrodes 43 and 44 are disposed in the vicinity of the surface inside the electrostatic chuck plate 40. The first and second adsorption electrodes 43 and 44 are connected to a chuck power supply 31 disposed outside the processing chamber 4. When the chuck power supply 31 is activated, the first and second adsorption electrodes 43 and 44 are activated. It is comprised so that a voltage can be applied between.
[0075]
A heater 45 is disposed inside the electrostatic chuck plate 40. The heater 45 is connected to a heater power source 32 disposed outside the processing chamber 4. When the heater power source 32 is activated, the heater 45 generates heat and the electrostatic chuck plate 40 can be heated. Has been.
[0076]
A target 33 made of a metal material such as aluminum is disposed on the ceiling side inside the processing chamber 4 so as to face the electrostatic chuck plate 40. The target 33 is connected to a DC power supply 34 disposed outside the processing chamber 4, and is configured such that when the DC power supply 34 is activated, a negative voltage is applied to the processing chamber 4.
[0077]
In a state where the substrate 50 is placed on the electrostatic chuck plate 40, the heater 45 generates heat in advance and the electrostatic chuck plate 40 is heated.
In this state, the chuck power supply 31 is activated and a first voltage is applied between the first and second adsorption electrodes 43 and 44 (here, the first and second adsorption electrodes 43 and 44 are When +3000 V and −3000 V are applied), an electrostatic attraction force is generated between the substrate 50 and the electrostatic chuck plate 40. This electrostatic attraction force increases with voltage application. When the electrostatic attraction force exceeds the minimum attraction force, the substrate 50 comes into close contact with the surface of the electrostatic chuck plate 40. When in close contact, the substrate 50 is heated by heat conduction from the electrostatic chuck plate 40.
[0078]
When the substrate 50 is heated and heated to a predetermined temperature, a sputtering gas such as argon gas is introduced into the processing chamber 4. The electrostatic chuck plate 40 is grounded, and the substrate 50 placed thereon is grounded. When the DC power supply 34 is activated and a negative voltage is applied to the target 33, a discharge occurs in the vicinity of the target 33, and the processing chamber 4 generates plasma, the material of the target 33 is sputtered, particles made of the sputtered target 33 material adhere to the surface of the substrate 50, and a thin film begins to be formed.
[0079]
When the thin film is formed, the voltage applied between the first and second adsorption electrodes 43 and 44 is changed, and a second voltage lower than the first voltage is applied (here, the first voltage is applied). , + 750V and -750V are applied to the second adsorption electrodes 43 and 44, respectively).
Here, after the first voltage is applied for 5 seconds, the applied voltage is changed to the second voltage. Thus, the applied voltage is changed to the second voltage V ₂ However, the electrostatic chuck plate 40 and the surface of the substrate 50 are in close contact with each other, and the attractive force that can be heated by heat conduction is maintained.
Then, after a thin film having a predetermined thickness is formed on the surface of the substrate 50, the DC power supply 4 is stopped and the plasma is extinguished. The film forming process is completed through the above steps.
[0080]
When the film forming process is completed in this way, a voltage having a polarity opposite to that applied at the end of the film forming process is applied between the first and second adsorption electrodes 43 and 44 (here, the first and second electrodes). (Apply voltages of −100 V and +100 V to the suction electrodes 43 and 44, respectively), the residual charge between the substrate 50 and the electrostatic chuck plate 40 is eliminated, the residual suction force is almost zero, and the substrate 50 is After making it easy to detach from the surface of the electric chuck plate 40, the elevating pins 61 are raised to detach the substrate 50 from the surface of the electrostatic chuck plate 40, and then the above-described substrate transfer is performed using the transfer robot 10 described above. The substrate 50 is carried out of the processing chamber 4 in the same procedure as the processing.
[0081]
If a constant high voltage is continuously applied between the first and second suction electrodes 43 and 44 until the film forming process is completed, the residual charge between the electrostatic chuck plate 40 and the substrate 50 is reduced. The film formation process ends when the residual charge disappears in a short time by applying a voltage of the opposite polarity to the voltage at the end of the film formation process after the film formation process is completed because the amount becomes large and the adsorption power becomes excessively large. A voltage having an absolute value larger than that of the hour must be applied.
[0082]
However, in the film forming process of this embodiment, the first voltage V is first applied to the first and second adsorption electrodes 43 and 44. ₁ Is applied for a predetermined time (here, 5 seconds) and the substrate 50 and the electrostatic chuck plate 40 are brought into close contact with each other. ₂ To the second voltage V ₂ Since the attracting force decreases and the amount of residual charges also decreases after the time of changing to, the attracting force between the substrate 50 and the electrostatic chuck plate 40 is applied with a constant voltage when the film forming process is completed. It is smaller than the case of continuing to do so.
[0083]
Therefore, by applying a voltage having an absolute value smaller than the voltage at the end of the film forming process and having a reverse polarity, the residual charge is eliminated in a short time, and the substrate 50 is easily detached from the surface of the electrostatic chuck plate 40. be able to.
[0084]
Thereby, since it is not necessary to comprise the chuck | zipper power supply 31 with a high voltage | pressure output power supply, the cost of the chuck | zipper power supply 31 can be reduced and the cost of the vacuum processing apparatus 1 can be reduced. In addition, no discharge occurs between the electrostatic chuck plate 40 and its peripheral device, and no discharge occurs between the first and second suction electrodes 43 and 44, thereby causing no failure of the device.
[0085]
In the above-described embodiment, as the vacuum processing method, the substrate transport process for transporting the substrate with the substrate electrostatically adsorbed and the film formation process for forming a thin film on the substrate surface have been described. The processing method is not limited to this, and any method can be applied as long as the substrate is processed in a state where the substrate is electrostatically adsorbed in a vacuum atmosphere.
[0086]
Further, in this embodiment, a soda-lime glass substrate is used as the substrate, but the substrate that can be electrostatically adsorbed by the vacuum processing method of the present invention is not limited to this, for example, plastic, silicon oxide, nitriding Any substrate having an insulating property, such as a substrate made of silicon or the like, can be applied to electrostatic adsorption of any substrate.
The method of the present invention is also effective as a method for appropriately controlling the adsorption force and suppressing the residual adsorption force even in electrostatic adsorption of a semiconductor substrate such as silicon.
[0087]
【The invention's effect】
The electrostatically attracted substrate can be detached from the electrostatic attracting device in a short time. In addition, since it is not necessary to configure the power supply for the electrostatic adsorption device with a high-voltage output power supply, the cost of the device can be reduced, and failure of the device due to discharge or the like can be suppressed.
[Brief description of the drawings]
FIG. 1 is a schematic configuration diagram showing an example of a vacuum processing apparatus for performing a vacuum processing method according to the present invention.
FIG. 2A is a cross-sectional view illustrating the configuration of an electrostatic adsorption device used in the vacuum processing method of the present invention.
(B): Plan view for explaining the configuration of the electrostatic chuck used in the vacuum processing method of the present invention
FIG. 3 is a first diagram illustrating a vacuum processing method according to the present invention.
FIG. 4 is a second diagram illustrating a vacuum processing method according to the present invention.
FIG. 5 is a third diagram illustrating the vacuum processing method of the present invention.
FIG. 6 is a fourth diagram illustrating the vacuum processing method of the present invention.
FIG. 7 is a fifth diagram illustrating the vacuum processing method of the present invention.
FIG. 8 is a sixth diagram illustrating the vacuum processing method of the present invention.
FIG. 9 is a seventh diagram illustrating the vacuum processing method of the present invention.
FIG. 10 is a first graph illustrating a time change of a voltage applied to an electrode and a time change of an adsorption force in the vacuum processing method of the present invention.
FIG. 11 is a second graph illustrating the time change of the voltage applied to the electrode and the time change of the adsorption force in the vacuum processing method of the present invention.
FIG. 12 is a third graph for explaining the change over time of the voltage applied to the electrode and the change over time of the adsorption force in the vacuum processing method of the present invention.
FIG. 13 is a fourth graph illustrating the time change of the voltage applied to the electrode and the time change of the adsorption force in the vacuum processing method of the present invention.
14A is a first diagram illustrating a conventional vacuum processing method; FIG.
(B): 2nd figure explaining the conventional vacuum processing method
(C): 3rd figure explaining the conventional vacuum processing method
FIG. 15D is a fourth diagram for explaining a conventional vacuum processing method;
(E): 5th figure explaining the conventional vacuum processing method
(F): 6th figure explaining the conventional vacuum processing method
FIG. 16 is a first graph illustrating a time change of a voltage applied to an electrode and a time change of an attracting force in a conventional vacuum processing method;
FIG. 17 is a second graph illustrating a time change of a voltage applied to an electrode and a time change of an attracting force in a conventional vacuum processing method.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Vacuum processing apparatus 2 ... Carry-in / out chamber 3 ... Transfer chamber 4 ... Processing chamber 13 ... Electrostatic adsorption apparatus 40 ... Electrostatic chuck plate (electrostatic adsorption apparatus) 50 ... Substrate

Claims (7)

A vacuum processing method for processing by electrostatically adsorbing a substrate in a vacuum,
Obtain in advance a minimum adsorption force that can be electrostatically adsorbed and suspended and moved;
The substrate is brought into contact with an electrostatic adsorption device, a first voltage for generating an adsorption force equal to or greater than the minimum adsorption force is applied between two electrodes disposed in the electrostatic adsorption device, and the minimum After the substrate is lifted with an attracting force equal to or greater than the attracting force, a voltage applied between the two electrodes is a second voltage that reduces the electrostatic attracting force between the electrostatic attracting device and the substrate. The adsorption force is reduced during the movement of the substrate by changing to the above, and the movement of the substrate is terminated while the electrostatic adsorption force between the electrostatic adsorption device and the substrate is greater than or equal to the minimum adsorption force. Vacuum processing method. The step of changing the voltage applied between the electrodes to the second voltage to reduce the electrostatic attraction force,
2. The vacuum processing method according to claim 1, wherein the vacuum processing method is performed after the first voltage is applied and before the electrostatic attraction force becomes equal to or greater than an upper limit attraction force larger than the minimum attraction force.   The vacuum processing method according to claim 1, wherein voltages having different polarities are applied between the electrodes.   In the step of changing the voltage applied between the electrodes to the second voltage to reduce the electrostatic attraction force, the potential difference between the two electrodes is applied to the first voltage. 4. The vacuum processing method according to claim 3, wherein the potential difference is smaller than the potential difference between the two electrodes in the process.   In the step of changing the voltage applied between the electrodes to the second voltage to reduce the electrostatic attraction force, the potential difference between the two electrodes is set to 0 volt. The vacuum processing method according to claim 3.   In the step of changing the voltage applied between the electrodes to the second voltage to reduce the electrostatic attraction force, the step of applying the first voltage between the two electrodes is performed. The vacuum processing method according to claim 3, wherein a voltage having a polarity opposite to the applied voltage is applied between the two electrodes. After changing the voltage applied between the electrodes to the second voltage to reduce the electrostatic attraction force,
The vacuum processing method according to claim 3, wherein a voltage at which a potential difference between the two electrodes changes stepwise is applied to the two electrodes.

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