JP2004342711A - Optical illumination apparatus, aligner, and exposure method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an aligner that illuminates a prescribed area not containing the optical axis of, for example, a catadioptric optical projection system and can satisfactorily compensate the error of the object-side telecentricity of the optical projection system, by using optical compensation elements readily positioned by avoiding mechanical interferences with other components without increasing the size of an optical element constituting an optical illumination system in the radial direction. <P>SOLUTION: Optical illumination equipment is deviated in a prescribed direction from the projection optical axis (AXp) of the catadioptric projection optical system (PL) on the object surface of the projection system (PL), so that the equipment may illuminate a prescribed area not containing the projection optical axis (AXp). The equipment has an illumination optical axis (AXi) passing the center of the prescribed area and is provided with two optical compensation elements for compensating the error of the object-side telecentricity of the optical projection system (PL). The optical compensation elements are disposed in a state where the elements are deviated from the illumination optical axis (AXi) along the direction optically corresponding to the prescribed direction. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

【００４４】
本実施形態において、両凹レンズＬ６１は球面レンズであって、レチクルＲ上のＹ方向に光学的に対応する方向に沿って図中の矢印Ｆ１の向きに１．０４８ｍｍだけ照明光軸ＡＸｉから偏心して配置された第１補償光学素子を構成している。正メニスカスレンズＬ６２は非球面レンズであって、レチクルＲ上のＹ方向に光学的に対応する方向に沿って図中の矢印Ｆ２の向きに６．７４９ｍｍだけ照明光軸ＡＸｉから偏心して配置された第２補償光学素子を構成している。正メニスカスレンズＬ６４は球面レンズであって、レチクルＲ上のＹ方向に光学的に対応する方向に沿って図中の矢印Ｆ３の向きに６．１７１ｍｍだけ照明光軸ＡＸｉから偏心して配置された第３補償光学素子を構成している。
【００４５】
両凸レンズＬ６６は非球面レンズであって、レチクルＲ上のＹ方向に光学的に対応する方向に沿って図中の矢印Ｆ４の向きに１．４３９ｍｍだけ照明光軸ＡＸｉから偏心して配置された第４補償光学素子を構成している。正メニスカスレンズＬ６７は球面レンズであって、レチクルＲ上のＹ方向に光学的に対応する方向に沿って図中の矢印Ｆ５の向きに５．２７７ｍｍだけ照明光軸ＡＸｉから偏心して配置された第５補償光学素子を構成している。正メニスカスレンズＬ６８は非球面レンズであって、レチクルＲ上のＹ方向に光学的に対応する方向に沿って図中の矢印Ｆ６の向きに５．３７１ｍｍだけ照明光軸ＡＸｉから偏心して配置された第６補償光学素子を構成している。
【００４６】
次の表（１）に、本実施形態にかかる結像光学系６の諸元の値を掲げる。表（１）の主要諸元において、λは露光光の中心波長を、βは結像倍率を、ＮＡは像側（レチクル側）開口数を、Ｃは投影光軸ＡＸｐに対する照明光軸ＡＸｉの偏心量をそれぞれ表している。また、Ｌｉｙ×Ｌｉｘは照明領域ＩＲの短辺方向寸法×長辺方向寸法を、Ｙｉは照明領域ＩＲにおける照明光軸ＡＸｉからの最大距離を、Ｌｏｙ×Ｌｏｘはレチクルブラインド５の光透過部５ａの短辺方向寸法×長辺方向寸法を、Ｙｏはレチクルブラインド５の光透過部５ａにおける照明光軸ＡＸｉからの最大距離をそれぞれ表している。
【００４７】
また、表（１）の光学部材諸元において、面番号はレチクルブラインド側からの光学面の順序を、ｒは各光学面の曲率半径（非球面の場合には頂点曲率半径：ｍｍ）を、ｄは各光学面の軸上間隔すなわち面間隔（ｍｍ）を、φは各光学面の有効径（直径：ｍｍ）を、ｎは露光光の中心波長に対する屈折率を、ｓは各補償光学素子の照明光軸ＡＸｉからの偏心量（ｍｍ）をそれぞれ示している。なお、各光学面の軸上間隔ｄは、各補償光学素子が偏心していない状態における軸上間隔を示している。
【００４８】
【表１】
（主要諸元）
λ＝１９３．３０６ｎｍ
β＝１．２５
ＮＡ＝０．２２１
Ｃ＝２２ｍｍ
Ｌｉｙ×Ｌｉｘ＝２０ｍｍ×１０４ｍｍ
Ｙｉ＝５２．９５ｍｍ
Ｌｏｙ×Ｌｏｘ＝１６ｍｍ×８３．２ｍｍ
Ｙｏ＝４２．３６ｍｍ

（非球面データ）
６面
κ＝０．００００００
Ｃ_４＝−９．２１４１７×１０^−９ Ｃ_６＝−３．３４３１２×１０^−１３
Ｃ_８＝−１．３６１０５×１０^−１６
１６面
κ＝０．００００００
Ｃ_４＝１．３０９３３×１０^−９ Ｃ_６＝−１．０８１５１×１０^−１５
Ｃ_８＝１．８２８３４×１０^−２０
２０面
κ＝０．００００００
Ｃ_４＝４．０４２２７×１０^−９ Ｃ_６＝２．２８０４７×１０^−１３
Ｃ_８＝−１．４３１６９×１０^−１７
【００４９】
図５〜図７は、本実施形態の結像光学系における横収差を示す図である。具体的には、図５は、レチクルＲ面に形成される矩形状の照明領域ＩＲにおいて照明光軸ＡＸｉを原点としてＹ＝０％，Ｘ＝１００％〜０％の座標位置に対応する横収差を示している。また、図６は、レチクルＲ面に形成される矩形状の照明領域ＩＲにおいて照明光軸ＡＸｉを原点としてＹ＝＋１００％，Ｘ＝１００％〜０％の座標位置に対応する横収差を示している。
【００５０】
さらに、図７は、レチクルＲ面に形成される矩形状の照明領域ＩＲにおいて照明光軸ＡＸｉを原点としてＹ＝−１００％，Ｘ＝１００％〜０％の座標位置に対応する横収差を示している。各収差図から明らかなように、本実施形態の結像光学系６では、横収差が良好に補正されている。なお、レチクルＲ面に形成される矩形状の照明領域ＩＲにおいて照明光軸ＡＸｉを原点とする座標位置については、図２（ａ）の表示を参照することができる。
【００５１】
本実施形態において、非球面レンズＬ６２、Ｌ６６およびＬ６８は、照明光軸ＡＸｉに関して回転対称な非球面形状の光学面を有するレンズを照明光軸ＡＸｉに対して偏心配置したものである。さらに換言すれば、非球面レンズＬ６２、Ｌ６６およびＬ６８は、投影光軸ＡＸｐに関して回転非対称な非球面形状の光学面を有するレンズである。そして、非球面レンズＬ６２における非球面形状の光学面の回転軸線の照明光軸ＡＸｉからの偏心量Ｂは６．７４９ｍｍであり、非球面レンズＬ６６における非球面形状の光学面の回転軸線の照明光軸ＡＸｉからの偏心量Ｂは１．４３９ｍｍであり、非球面レンズＬ６８における非球面形状の光学面の回転軸線の照明光軸ＡＸｉからの偏心量Ｂは５．３７１ｍｍである。
【００５２】
一方、球面レンズＬ６１の照明光軸ＡＸｉからの偏心量Ａは１．０４８ｍｍであり、球面レンズＬ６４の照明光軸ＡＸｉからの偏心量Ａは６．１７１ｍｍであり、球面レンズＬ６７の照明光軸ＡＸｉからの偏心量Ａは５．２７７ｍｍである。さらに、表（１）を参照すると、レチクルブラインド５に最も近い第１補償光学素子すなわち球面レンズＬ６１からレチクルブラインド５までの軸上距離Ｄｏは５８．２２４ｍｍであり、レチクルＲに最も近い第６補償光学素子すなわち非球面レンズＬ６８からレチクルＲまでの軸上距離Ｄｉは１８５．７８８ｍｍである。
【００５３】
図８は、本実施形態における投影光学系の物体側テレセントリシティの誤差を模式的に示す図である。図８では、本実施形態における投影光学系ＰＬの物体面（レチクルＲのパターン面）における照明領域ＩＲの範囲内を通過する各主光線の位置と、投影光学系ＰＬの物体面から所定距離だけウェハ側において物体面と平行に設定された所定平行面を通過する当該主光線の位置とを結ぶ線分が、そのＸ方向成分に対応する線分およびＹ方向成分に対応する線分とともに示されている。なお、上述の表記は、以下の対応する図９および図１０においても同様である。
【００５４】
投影光学系ＰＬにおいて物体側（レチクル側）テレセントリシティの誤差が全くない場合、物体面の法線に対する主光線の傾きすなわち投影光軸ＡＸｐや照明光軸ＡＸｉに対する主光線の傾きが全くなく、図８にはマトリックス状に点だけが現われることになる。しかしながら、実際には、図８に示すように、照明領域ＩＲを通過する各主光線は、図中左上端の位置（照明光軸ＡＸｉを原点としてＸ＝−１００％，Ｙ＝−１００％の座標位置）および左下端の位置（照明光軸ＡＸｉを原点としてＸ＝＋１００％，Ｙ＝−１００％の座標位置）を除き、投影光軸ＡＸｐに向かって傾き、物体側テレセントリシティの誤差が発生する。
【００５５】
ここで、投影光学系ＰＬの物体側テレセントリシティの誤差分布は、照明光軸ＡＸｉを原点とするＹ軸に関して対称である。なお、図８の右下に主光線の１ｍｒａｄの傾きに対応する線分を示しているが、投影光学系ＰＬにおける物体側テレセントリシティのＸ方向の最大誤差成分は３．２３×１０^−３ラジアンすなわち３．２３ｍｒａｄであり、Ｙ方向の最大誤差成分は３．４６ｍｒａｄである。
【００５６】
図９は、本実施形態における結像光学系によるテレセントリシティの補償作用を模式的に示す図である。また、図１０は、本実施形態における投影光学系の物体側テレセントリシティの誤差が結像光学系により補償された結果を模式的に示す図である。本実施形態では、投影光学系ＰＬの物体側テレセントリシティの誤差を補償するために、６つの補償光学素子（Ｌ６１，Ｌ６２，Ｌ６４，Ｌ６６，Ｌ６７，Ｌ６８）を用いて、図９に示すように、投影光学系ＰＬの物体側テレセントリシティの誤差分布と逆の傾向を有する像側（レチクル側）テレセントリシティの誤差分布を結像光学系６に付与している。
【００５７】
なお、図９の右下に主光線の１ｍｒａｄの傾きに対応する線分を示しているが、結像光学系６における像側テレセントリシティのＸ方向の最大誤差成分は２．３９ｍｒａｄであり、Ｙ方向の最大誤差成分は２．５６ｍｒａｄである。その結果、本実施形態では、図１０に示すように、投影光学系ＰＬの物体側テレセントリシティの誤差が結像光学系６の作用により良好に補償されている。なお、図１０の右下に主光線の１ｍｒａｄの傾きに対応する線分を示しているが、結像光学系６により補償された投影光学系ＰＬにおける物体側テレセントリシティのＸ方向の最大誤差成分は０．８５ｍｒａｄであり、Ｙ方向の最大誤差成分は０．９８ｍｒａｄである。
【００５８】
以上のように、本実施形態では、照明光軸ＡＸｉと投影光軸ＡＸｐとが一致することなく、投影光軸ＡＸｐからＹ方向に偏心して投影光軸ＡＸｐを含まない照明領域ＩＲの中心を照明光軸ＡＸｉが通るように設定されているので、照明光学系を構成する各光学素子が径方向に大型化することなく、ひいては照明光学装置（１〜６）が巨大化することがない。また、結像光学系６の光路中において偏心配置された６つの補償光学素子を用いているので、レチクルブラインド５やレチクルステージやアライメント系と機械的に干渉しないように補償光学素子をレチクルブラインド５およびレチクルＲから十分に間隔を隔てて配置しても、ディストーションを実質的に発生させることなく、投影光学系ＰＬの物体側テレセントリシティの誤差を良好に補償することができる。
【００５９】
したがって、本実施形態では、反射屈折型投影光学系ＰＬの投影光軸ＡＸｐを含まない照明領域ＩＲを照明する露光装置において、照明光学系を構成する光学素子が径方向に大型化することなく（すなわち照明光学装置（１〜６）のコンパクト化を図りつつ）、他の部品との機械的干渉を回避して容易に配置された補償光学素子を用いて投影光学系の物体側テレセントリシティの誤差を良好に補償することができる。その結果、本実施形態では、投影光学系ＰＬの物体側テレセントリシティの誤差を良好に補償することのできるコンパクトな照明光学装置（１〜６）を用いて、高解像で高精度な投影露光を行うことができる。
【００６０】
なお、上述の実施形態では、補償光学素子として、照明光軸ＡＸｉに対して偏心配置された３つの球面レンズＬ６１、Ｌ６４およびＬ６７と、照明光軸ＡＸｉに対して偏心した回転軸線を有する（投影光軸ＡＸｐに関して回転非対称な非球面形状の光学面を有する）３つの非球面レンズＬ６２、Ｌ６６およびＬ６８とを用いてる。しかしながら、一般的には、照明光軸ＡＸｉに対して偏心配置された球面レンズであると、投影光軸ＡＸｐに関して回転非対称な非球面形状の光学面を有する非球面レンズであるとを問わず、少なくとも２つの補償光学素子を用いて、ディストーションを実質的に発生させることなく、投影光学系ＰＬの物体側テレセントリシティの誤差を良好に補償することができる。
【００６１】
この場合、ディストーションの発生をさらに良好に抑えつつ投影光学系ＰＬの物体側テレセントリシティの誤差をさらに良好に補償するには、結像光学系６の瞳面（開口絞りＡＳの位置またはその近傍）に関して一方の側に少なくとも２つの補償光学素子が配置されていることが好ましい。また、同じ理由により、少なくとも２つの補償光学素子が照明光軸ＡＸｉに対して偏心配置された２つの球面レンズを含む場合、これらの２つの球面レンズの偏心量Ａが互いに異なることが好ましい。さらに、同じ理由により、少なくとも２つの補償光学素子が非球面レンズを含む場合、当該非球面レンズの非球面形状の光学面は照明光軸ＡＸｉおよび投影光軸ＡＸｐから偏心した基準軸（回転軸線）を有することが好ましい。
【００６２】
また、本発明では、少なくとも２つの補償光学素子が照明光軸ＡＸｉに対して偏心配置された球面レンズを含む場合、当該球面レンズの照明光軸ＡＸｉからの偏心量Ａは次の条件式（１）を満足することが好ましい。
Ａ＜Ｃ×０．９ （１）
【００６３】
本実施形態では、第１補償光学素子である球面レンズＬ６１の偏心量Ａは１．０４８ｍｍであり、第３補償光学素子である球面レンズＬ６４の照明光軸ＡＸｉからの偏心量Ａは６．１７１ｍｍであり、第５補償光学素子である球面レンズＬ６７の照明光軸ＡＸｉからの偏心量Ａは５．２７７ｍｍであり、Ｃ×０．９は２２×０．９＝１９．８ｍｍである。したがって、本実施形態では、各補償光学素子が条件式（１）を満足している。換言すれば、少なくとも２つの補償光学素子を用いることにより、条件式（１）を満足することができる程度まで、当該補償光学素子の偏心量Ａを小さく抑えることができる。
【００６４】
また、本発明では、少なくとも２つの補償光学素子が照明光軸ＡＸｉに対して偏心配置された回転軸線を有する非球面レンズを含む場合、当該非球面レンズにおける非球面形状の光学面の回転軸線の照明光軸ＡＸｉからの偏心量Ｂは次の条件式（２）を満足することが好ましい。
Ｂ＜Ｃ×０．９ （２）
【００６５】
本実施形態では、第２補償光学素子である非球面レンズＬ６２における非球面形状の光学面の回転軸線の照明光軸ＡＸｉからの偏心量Ｂは６．７４９ｍｍであり、第４補償光学素子である非球面レンズＬ６６における非球面形状の光学面の回転軸線の照明光軸ＡＸｉからの偏心量Ｂは１．４３９ｍｍであり、第６補償光学素子である非球面レンズＬ６８における非球面形状の光学面の回転軸線の照明光軸ＡＸｉからの偏心量Ｂは５．３７１ｍｍであり、Ｃ×０．９は２２×０．９＝１９．８ｍｍである。したがって、本実施形態では、各補償光学素子が条件式（２）を満足している。換言すれば、少なくとも２つの補償光学素子を用いることにより、条件式（２）を満足することができる程度まで、当該補償光学素子の偏心量Ｂを小さく抑えることができる。
【００６６】
また、本発明では、補償光学素子が次の条件式（３）および（４）を満足することが好ましい。なお、条件式（３）および（４）において、Ｄは、レチクルブラインド５に最も近い補償光学素子からレチクルブラインド５までの軸上距離ＤｏとレチクルＲに最も近い補償光学素子からレチクルＲまでの軸上距離Ｄｉとのうち小さい方の距離である。
Ｄ＞Ｙｏ×０．６ （３）
Ｄ＞Ｙｉ×０．６ （４）
【００６７】
上述したように、レチクルブラインド５に最も近い第１補償光学素子すなわち球面レンズＬ６１からレチクルブラインド５までの軸上距離Ｄｏは５８．２２４ｍｍであり、レチクルＲに最も近い第６補償光学素子すなわち非球面レンズＬ６８からレチクルＲまでの軸上距離Ｄｉは１８５．７８８ｍｍである。一方、レチクルブラインド５の光透過部における照明光軸ＡＸｉからの最大距離Ｙｏは４２．３６ｍｍであり、照明領域ＩＲにおける照明光軸ＡＸｉからの最大距離Ｙｉは５２．９５ｍｍである。
【００６８】
したがって、距離ＤがＤｏ＝５８．２２４ｍｍであるのに対し、Ｙｏ×０．６は４２．３６×０．６＝２５．４１６ｍｍであり、Ｙｉ×０．６は５２．９５×０．６＝３１．７７ｍｍである。その結果、本実施形態では、補償光学素子が条件式（３）および（４）を満足している。換言すれば、少なくとも２つの補償光学素子を用いることにより、条件式（３）および（４）を満足することができる程度まで、補償光学素子をレチクルＲおよびレチクルブラインド５から十分に間隔を隔てて配置することができる。
【００６９】
また、上述の実施形態では、結像光学系６の光路中に複数の補償光学素子を配置しているが、これに限定されることなく、たとえばオプティカルインテグレータとしてのマイクロレンズアレイ３とレチクルＲとの間の光路中など、他の適当な照明光路中に複数の補償光学素子を配置することもできる。
【００７０】
ところで、上述の実施形態において、補償光学素子の製造誤差や位置決め誤差などの影響を補正するための調整光学素子を備えていることが好ましい。ここで、調整光学素子として、照明光軸ＡＸｉに沿って移動可能な屈折光学素子（レンズ）や、照明光軸ＡＸｉに対して傾動可能な屈折光学素子や、照明光軸ＡＸｉと交差する方向に沿って移動可能な屈折光学素子を用いることができる。
【００７１】
図１１は、本実施形態の第１変形例における投影光学系の具体的な構成を概略的に示す図である。本実施形態の第１変形例における投影光学系ＰＬは、図１１に示すように、投影原版としてのレチクルＲに形成されたパターンの中間像を形成するための反射屈折型の第１結像光学系Ｇ１と、第１結像光学系Ｇ１による中間像の像をワークとしてのウェハ（感光性基板）Ｗ上に再結像させるための屈折型の第２結像光学系Ｇ２とにより構成されている。
【００７２】
ここで、レチクルＲと第１結像光学系Ｇ１との間の光路中には、光路を９０°だけ偏向させるための光路折り曲げ用の反射面４１が配置されている。また、第１結像光学系Ｇ１と第２結像光学系Ｇ２との間の光路中、すなわち中間像の近傍には、光路を９０°だけ偏向させるための光路折り曲げ用の反射面４２が配置されている。これらの反射面４１および４２は、光路折り曲げ部材ＦＭ上に設けられている。また、第１結像光学系Ｇ１は、光軸ＡＸ１に沿って配置された複数のレンズ成分と凹面反射鏡ＣＭとを有しており、ほぼ等倍又はやや縮小倍率のもとで中間像を形成する。
【００７３】
第２結像光学系Ｇ２は、光軸ＡＸ１と直交する光軸ＡＸ２上に沿って配置された複数のレンズ成分及びコヒーレンスファクタを制御するための可変開口絞りＡＳを有し、中間像からの光に基づいて縮小倍率のもとで中間像の像、すなわち２次像を形成する。ここで、第１結像光学系Ｇ１の光軸ＡＸ１は光路折り曲げ用反射面４１によって９０°折り曲げられて、レチクルＲと反射面４１との間に光軸ＡＸ０を定義している。本実施形態では、光軸ＡＸ０と光軸ＡＸ２とは互いに平行であるが、一致はしていない。
【００７４】
なお、第１変形例において、光軸ＡＸ０に沿って１つまたは複数のレンズ成分を配置してもよい。また、光軸ＡＸ０と光軸ＡＸ２とを互いに一致するように配置してもよい。また、光軸ＡＸ０と光軸ＡＸ１とのなす角度を９０°とは異なる角度、好ましくは凹面反射鏡ＣＭを反時計回りに回転させた角度としても良い。このとき、反射面４２での光軸の折り曲げ角度を、レチクルＲとウェハＷとが平行になるように設定することが好ましい。
【００７５】
図１２は、本実施形態の第２変形例における投影光学系の具体的な構成を概略的に示す図である。本実施形態の第２変形例における投影光学系ＰＬは、図１２に示すように、投影原版としてのレチクルＲに形成されたパターンの中間像を形成するための反射屈折型の第１結像光学系Ｇ１と、第１結像光学系Ｇ１による中間像の像をワークとしてのウェハ（感光性基板）Ｗ上に最結像させるための屈折型の第２結像光学系Ｇ２とにより構成されている。
【００７６】
第１結像光学系Ｇ１と第２結像光学系Ｇ２との間の光路中には、光路を９０°だけ偏向させるための光路折り曲げ用の反射面５１と、光路を９０°だけ偏向させるための光路折り曲げ用の反射面５２とが配置されている。第１結像光学系Ｇ１は、光軸ＡＸ１に沿って配置された複数のレンズ成分及び凹面反射鏡ＣＭを有し、ほぼ等倍あるいはやや縮小倍率でレチクルＲの中間像を第１光路折り曲げ鏡としての反射面５１の近傍に形成する。
【００７７】
第２結像光学系Ｇ２は、光軸ＡＸ２に沿って配置された複数のレンズ成分を有し、中間像からの光に基づいて、中間像の像（２次像）をウェハＷ上に縮小倍率で形成する。ここで、反射面５１と反射面５２とが互いに直交するような角度で配置されているため、第１結像光学系Ｇ１の光軸ＡＸ１と第２結像光学系Ｇ２の光軸ＡＸ２とは互いに平行になり、レチクルＲとウェハＷとも互いに平行となる。なお、第２変形例において、光路折り曲げ用の反射面５１と５２との間の光路中に、１つまたは複数のレンズ成分を光軸ＡＸ３に沿って配置しても良い。
【００７８】
上述の実施形態にかかる露光装置では、照明光学装置によってマスク（レチクル）を照明し（照明工程）、投影光学系を用いてマスクに形成された転写用のパターンを感光性基板に露光する（露光工程）ことにより、マイクロデバイス（半導体素子、撮像素子、液晶表示素子、薄膜磁気ヘッド等）を製造することができる。以下、本実施形態の露光装置を用いて感光性基板としてのウェハ等に所定の回路パターンを形成することによって、マイクロデバイスとしての半導体デバイスを得る際の手法の一例につき図１３のフローチャートを参照して説明する。
【００７９】
先ず、図１３のステップ３０１において、１ロットのウェハ上に金属膜が蒸着される。次のステップ３０２において、そのｌロットのウェハ上の金属膜上にフォトレジストが塗布される。その後、ステップ３０３において、本実施形態の露光装置を用いて、マスク上のパターンの像がその投影光学系を介して、その１ロットのウェハ上の各ショット領域に順次露光転写される。その後、ステップ３０４において、その１ロットのウェハ上のフォトレジストの現像が行われた後、ステップ３０５において、その１ロットのウェハ上でレジストパターンをマスクとしてエッチングを行うことによって、マスク上のパターンに対応する回路パターンが、各ウェハ上の各ショット領域に形成される。その後、更に上のレイヤの回路パターンの形成等を行うことによって、半導体素子等のデバイスが製造される。上述の半導体デバイス製造方法によれば、極めて微細な回路パターンを有する半導体デバイスをスループット良く得ることができる。
【００８０】
また、本実施形態の露光装置では、プレート（ガラス基板）上に所定のパターン（回路パターン、電極パターン等）を形成することによって、マイクロデバイスとしての液晶表示素子を得ることもできる。以下、図１４のフローチャートを参照して、このときの手法の一例につき説明する。図１４において、パターン形成工程４０１では、本実施形態の露光装置を用いてマスクのパターンを感光性基板（レジストが塗布されたガラス基板等）に転写露光する、所謂光リソグラフィー工程が実行される。この光リソグラフィー工程によって、感光性基板上には多数の電極等を含む所定パターンが形成される。その後、露光された基板は、現像工程、エッチング工程、レジスト剥離工程等の各工程を経ることによって、基板上に所定のパターンが形成され、次のカラーフィルター形成工程４０２へ移行する。
【００８１】
次に、カラーフィルター形成工程４０２では、Ｒ（Ｒｅｄ）、Ｇ（Ｇｒｅｅｎ）、Ｂ（Ｂｌｕｅ）に対応した３つのドットの組がマトリックス状に多数配列されたり、またはＲ、Ｇ、Ｂの３本のストライプのフィルターの組を複数水平走査線方向に配列したカラーフィルターを形成する。そして、カラーフィルター形成工程４０２の後に、セル組み立て工程４０３が実行される。セル組み立て工程４０３では、パターン形成工程４０１にて得られた所定パターンを有する基板、およびカラーフィルター形成工程４０２にて得られたカラーフィルター等を用いて液晶パネル（液晶セル）を組み立てる。セル組み立て工程４０３では、例えば、パターン形成工程４０１にて得られた所定パターンを有する基板とカラーフィルター形成工程４０２にて得られたカラーフィルターとの間に液晶を注入して、液晶パネル（液晶セル）を製造する。
【００８２】
その後、モジュール組み立て工程４０４にて、組み立てられた液晶パネル（液晶セル）の表示動作を行わせる電気回路、バックライト等の各部品を取り付けて液晶表示素子として完成させる。上述の液晶表示素子の製造方法によれば、極めて微細な回路パターンを有する液晶表示素子をスループット良く得ることができる。
【００８３】
なお、上述の実施形態では、ＡｒＦエキシマレーザー光源を用いているが、これに限定されることなく、たとえば波長が２４８ｎｍの光を供給するＫｒＦエキシマレーザー光源や波長が１５６ｎｍの光を供給するＦ_２エキシマレーザー光源のような他の適当な光源を用いることもできる。また、上述の実施形態では、照明光学装置を備えた投影露光装置を例にとって本発明を説明したが、マスク以外の被照射面を照明するための一般的な照明光学装置に本発明を適用することができることは明らかである。
【００８４】
【発明の効果】
以上説明したように、本発明の照明光学装置では、反射屈折型投影光学系の投影光軸を含まない照明領域を照明する露光装置において、たとえば照明光軸から偏心して配置された少なくとも２つの補償光学素子を用いることにより、照明光学系を構成する光学素子が径方向に大型化することなく、すなわち照明光学装置のコンパクト化を図りつつ、他の部品との機械的干渉を回避して容易に配置された補償光学素子を用いて投影光学系の物体側テレセントリシティの誤差を良好に補償することができる。
【００８５】
したがって、本発明の照明光学装置を用いる露光装置および露光方法では、投影光学系の物体側テレセントリシティの誤差を良好に補償することのできるコンパクトな照明光学装置を用いて、高解像で高精度な投影露光を行うことができ、ひいては良好なデバイスを高精度に製造することができる。
【図面の簡単な説明】
【図１】本発明の実施形態にかかる照明光学装置を備えた露光装置の構成を概略的に示す図である。
【図２】本実施形態における照明光学装置の照明光軸と投影光学系の投影光軸との位置関係およびレチクルブラインドの光透過部の構成を概略的に示す図である。
【図３】本実施形態における投影光学系の具体的な構成を概略的に示す図である。
【図４】本実施形態における結像光学系の具体的な構成を概略的に示す図である。
【図５】レチクル面に形成される矩形状の照明領域において照明光軸を原点としてＹ＝０％，Ｘ＝１００％〜０％の座標位置に対応する横収差を示す図である。
【図６】レチクル面に形成される矩形状の照明領域において照明光軸を原点としてＹ＝＋１００％，Ｘ＝１００％〜０％の座標位置に対応する横収差を示す図である。
【図７】レチクル面に形成される矩形状の照明領域において照明光軸を原点としてＹ＝−１００％，Ｘ＝１００％〜０％の座標位置に対応する横収差を示す図である。
【図８】本実施形態における投影光学系の物体側テレセントリシティの誤差を模式的に示す図である。
【図９】本実施形態における結像光学系によるテレセントリシティの補償作用を模式的に示す図である。
【図１０】本実施形態における投影光学系の物体側テレセントリシティの誤差が結像光学系により補償された結果を模式的に示す図である。
【図１１】本実施形態の第１変形例における投影光学系の具体的な構成を概略的に示す図である。
【図１２】本実施形態の第２変形例における投影光学系の具体的な構成を概略的に示す図である。
【図１３】マイクロデバイスとしての半導体デバイスを得る際の手法のフローチャートである。
【図１４】マイクロデバイスとしての液晶表示素子を得る際の手法のフローチャートである。
【符号の説明】
１ 光源
３ マイクロレンズアレイ
４ コンデンサー光学系
５ レチクルブラインド（照明視野絞り）
６ 結像光学系
Ｒ レチクル
ＰＬ 投影光学系
Ｗ ウェハ
ＡＸｐ 投影光軸
ＡＸｉ 照明光軸
Ｌ６１〜Ｌ６８ 補償光学素子[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an illumination optical apparatus, an exposure apparatus, and an exposure method, and particularly to an illumination optical apparatus suitable for an exposure apparatus for manufacturing micro devices such as a semiconductor device, an imaging device, a liquid crystal display device, and a thin-film magnetic head by a lithography process. About.
[0002]
[Prior art]
When manufacturing a semiconductor element or the like, an exposure apparatus for transferring a pattern image of a reticle as a mask onto a wafer (or a glass plate or the like) coated with a resist via a projection optical system is used. In addition, as a type of the exposure apparatus, a reticle pattern is collectively exposed to each exposure region of the wafer according to a step-and-repeat method, or a reticle pattern is scanned and exposed to each exposure region of the wafer according to a step-and-scan method. There is a type to do.
[0003]
In this type of exposure apparatus, as the pattern of a semiconductor integrated circuit or the like becomes finer, it is desired to improve the resolving power of a projection optical system. In order to improve the resolution of the projection optical system, it is conceivable to shorten the wavelength of the exposure light or increase the numerical aperture. In recent years, exposure light has been shifting from g-line (436 nm) and i-line (365 nm) of mercury lamps to shorter wavelength KrF excimer laser light (248 nm) and ArF excimer laser light (193 nm).
[0004]
However, when the wavelength of the exposure light is shortened to improve the resolution of the projection optical system, the types of optical materials having a predetermined transmittance that can be used for the optical members constituting the projection optical system are limited. This makes the design of the projection optical system difficult. Specifically, in a projection optical system using KrF excimer laser light or ArF excimer laser light, usable optical materials are substantially limited to quartz or fluorite having a relatively low refractive index. Further, F₂In a projection optical system using excimer laser light (157 nm), usable optical materials are substantially limited to fluorite.
[0005]
These optical materials are very expensive, and it is very difficult to realize a high-quality large-aperture lens using these optical materials. Therefore, in order to achieve a high numerical aperture using limited optical materials, catadioptric projection using an area that does not include an optical axis (an axis that is an arrangement reference of optical elements constituting an optical system) as an exposure area. Optical systems have been proposed. Various illumination optical devices have been proposed for suitably illuminating a reticle in an exposure apparatus equipped with this type of catadioptric projection optical system.
[0006]
[Problems to be solved by the invention]
In this type of catadioptric projection optical system, the residual aberration is suppressed to be extremely small in order to achieve a high resolution. However, in reality, the pupil aberration is not completely corrected by design. In other words, the projection optical system is designed to be telecentric on both sides, but an error in telecentricity (a slight inclination of the principal ray with respect to the normal to the object plane) occurs on the reticle side (object side). I do. Therefore, the error (pupil aberration) of the object-side telecentricity of the catadioptric projection optical system needs to be almost completely compensated for by the illumination optical device.
[0007]
In order to compensate for the error of the object-side telecentricity of the catadioptric projection optical system by the illumination optical device, for example, Japanese Patent Application Laid-Open No. 2000-21765 discloses an optical axis of the illumination optical device (hereinafter referred to as “illumination optical axis”). ) And the optical axis of the projection optical system (hereinafter, referred to as “projection optical axis”) have been proposed. However, in an exposure apparatus equipped with a catadioptric projection optical system having an exposure area that does not include the projection optical axis as described above, when the projection optical axis and the illumination optical axis are made to coincide with each other, compensation for a telecentricity error is not possible. Although it is relatively easy, the size of the optical element constituting the illumination optical system increases in the radial direction, and the size of the illumination optical device is increased. Optical materials that can be used for the illumination optical system are also subject to the same restrictions as in the case of the projection optical system, so that it is very difficult to realize a large-diameter lens in the illumination optical system.
[0008]
Further, in order to compensate for the error of the object side telecentricity of the catadioptric projection optical system by an illumination optical device, for example, Japanese Patent Application Laid-Open No. 2001-237183 discloses that an illumination optical axis is optically corresponded to the center of an exposure area. (I.e., the illumination optical axis and the center of the illumination area on the reticle coincide), and a wedge-type compensating optical element is arranged near the reticle (i.e., immediately above the reticle). . Similarly, for example, Japanese Patent Application Laid-Open No. 2001-308006 discloses an adaptive optics in which an illumination optical axis is set to coincide with the center of an illumination area on a reticle, and has an optical axis different from the illumination optical axis near the reticle. A configuration in which elements are arranged has been proposed.
[0009]
However, in the exposure apparatus, the above-described compensating optical element to be disposed near the reticle has a reticle stage for holding and moving the reticle and an alignment system for highly accurately aligning the reticle with respect to the projection optical system. There is a disadvantage that mechanical interference easily occurs, and as a result, it is difficult to arrange the adaptive optics at a required position near the reticle. In particular, in the case of a scanning exposure type exposure apparatus, since the reticle stage moves frequently and over a wide range, there is a disadvantage that it is more difficult to arrange the adaptive optics at a required position near the reticle. .
[0010]
The present invention has been made in view of the above-described problems. For example, in an exposure apparatus that illuminates a predetermined region not including an optical axis of a catadioptric projection optical system, an optical element forming an illumination optical system is radially oriented. Illumination optics capable of satisfactorily compensating for an object-side telecentricity error of a projection optical system by using an easily arranged compensating optical element while avoiding mechanical interference with other components without increasing the size. It is intended to provide a device. In addition, the present invention provides an exposure apparatus capable of performing high-resolution and high-accuracy projection exposure using a compact illumination optical apparatus capable of favorably compensating for an error in the object-side telecentricity of the projection optical system. It is an object to provide an apparatus and an exposure method.
[0011]
[Means for Solving the Problems]
In order to solve the above problem, in a first embodiment of the present invention, a predetermined area which is decentered in a predetermined direction from a projection optical axis of the projection optical system and does not include the projection optical axis on an object plane of a catadioptric projection optical system. An illumination optical device for illuminating
The illumination optical device has an illumination optical axis passing through the center of the predetermined area,
Comprising two compensating optical elements for compensating for an error in the object-side telecentricity of the projection optical system,
The illumination optical device is characterized in that the two compensation optical elements are arranged eccentrically from the illumination optical axis along a direction optically corresponding to the predetermined direction.
[0012]
According to a preferred aspect of the first aspect, the eccentric amounts of the two compensation optical elements from the illumination optical axis are different from each other.
[0013]
According to a second embodiment of the present invention, an illumination optical apparatus for illuminating a predetermined area which is decentered in a predetermined direction from a projection optical axis of the projection optical system on an object plane of a catadioptric projection optical system and does not include the projection optical axis. At
The illumination optical device has an illumination optical axis passing through the center of the predetermined area,
Comprising two compensating optical elements for compensating for an error in the object-side telecentricity of the projection optical system,
One of the two compensation optical elements is disposed eccentrically from the illumination optical axis along a direction optically corresponding to the predetermined direction,
The other of the two compensating optical elements has an aspherical optical surface that is rotationally asymmetric with respect to the illumination optical axis.
[0014]
According to a third aspect of the present invention, there is provided an illumination optical apparatus for illuminating a predetermined area not including the projection optical axis by decentering in a predetermined direction from a projection optical axis of the projection optical system on an object plane of a catadioptric projection optical system. At
The illumination optical device has an illumination optical axis passing through the center of the predetermined area,
Comprising two compensating optical elements for compensating for an error in the object-side telecentricity of the projection optical system,
The illumination optical device is characterized in that the two adaptive optics have an aspheric optical surface that is rotationally asymmetric with respect to the illumination optical axis.
[0015]
According to a preferred mode of the second mode and the third mode, the aspherical shape which is rotationally asymmetric with respect to the illumination optical axis has a reference axis decentered from the illumination optical axis and the projection optical axis.
[0016]
According to a preferred aspect of the first to third embodiments, a light source for supplying a light beam, and a secondary light source arranged in an optical path between the light source and the object surface and based on the light beam from the light source And an optical integrator for forming the first and second adaptive optics, wherein the two adaptive optics are disposed in an optical path between the optical integrator and the object plane. In this case, the apparatus further comprises a light guiding optical system for guiding a light beam from the secondary light source to the object surface, wherein the light guiding optical system is disposed at a position optically conjugate with the object surface, and A field stop for defining the shape and size of the illumination area formed in the, and an imaging optical system for forming an image of a light transmitting portion of the field stop on the object plane, It is preferable that the two adaptive optics are arranged in the optical path of the imaging optical system. In this case, it is preferable that the two compensating optical elements are arranged on one side with respect to a pupil plane of the imaging optical system.
[0017]
According to a preferred aspect of the first aspect, for the two compensating optical elements, A is the amount of eccentricity of each of the compensating optical elements from the illumination optical axis, and C is the amount of eccentricity of the illumination optical axis with respect to the projection optical axis. and when,
A <C × 0.9
Satisfies the condition.
[0018]
According to a preferred aspect of the second aspect, the eccentricity of the one compensating optical element from the illumination optical axis is A, and the illumination optical axis of a rotation axis of an aspherical optical surface of the other compensating optical element. When the eccentricity of the illumination optical axis with respect to the projection optical axis is C,
A <C × 0.9
B <C × 0.9
Satisfies the condition.
[0019]
According to a preferred aspect of the third mode, for the two compensation optical elements, the amount of eccentricity of the rotation axis of the aspherical optical surface of each compensation optical element from the illumination optical axis is B, and When the eccentric amount of the illumination optical axis is C,
B <C × 0.9
Satisfies the condition.
[0020]
According to a preferred mode of the first to third embodiments, the smaller of the two compensating optical elements, the distance from each compensating optical element to the field stop and the distance from each compensating optical element to the object plane. Is D, the distance from the illumination optical axis at a position farthest from the illumination optical axis in the light transmitting portion of the field stop is Yo, and the distance from the illumination optical axis is greater in the predetermined area of the object plane. When the distance from the illumination optical axis of the position
D> Yo × 0.6
D> Yi × 0.6
Satisfies the condition.
[0021]
According to a preferred embodiment of the first to third embodiments, the refractive optical element movable along the illumination optical axis, the refractive optical element tiltable with respect to the illumination optical axis, and the illumination optical axis. The apparatus further includes at least one refractive optical element that is movable along the crossing direction.
[0022]
According to a fourth aspect of the present invention, the illumination optical device according to any one of the first to third aspects and the reflective projection optical system for projecting and exposing a pattern of a mask disposed on the object plane onto a photosensitive substrate are provided. An exposure apparatus is provided.
[0023]
According to a fifth aspect of the present invention, a mask disposed on the object plane is illuminated via the illumination optical device according to the first to third aspects, and a pattern formed on the illuminated mask is projected by the reflection type. There is provided an exposure method, which comprises exposing a photosensitive substrate via an optical system.
[0024]
BEST MODE FOR CARRYING OUT THE INVENTION
An embodiment of the present invention will be described with reference to the accompanying drawings.
FIG. 1 is a view schematically showing a configuration of an exposure apparatus provided with an illumination optical device according to an embodiment of the present invention. In FIG. 1, the Z axis is along the normal direction of the wafer W as a photosensitive substrate, the Y axis is in the direction parallel to the plane of FIG. 1 in the wafer plane, and the Z axis is perpendicular to the plane of FIG. 1 in the wafer plane. The X axis is set in each direction.
[0025]
The exposure apparatus in FIG. 1 includes an ArF excimer laser light source that supplies light having a wavelength of about 193 nm as a light source 1 for supplying exposure light (illumination light). A substantially parallel light beam emitted from the light source 1 along the Y direction has a rectangular cross section elongated in the X direction, and enters a beam expander 2 including a pair of lenses 2a and 2b. Each of the lenses 2a and 2b has a negative refractive power and a positive refractive power in FIG. 1, respectively. At least one of the pair of lenses 2a and 2b is configured to be movable along the optical axis (illumination optical axis) AXi of the illumination optical device.
[0026]
Therefore, the light beam incident on the beam expander 2 is enlarged in the paper of FIG. 1 according to the distance between the pair of lenses 2a and 2b, and shaped into a light beam having a desired rectangular cross section. A substantially parallel light beam passing through a beam expander 2 as a shaping optical system enters a microlens array (or fly-eye lens) 3. The microlens array 3 is, for example, an optical element composed of a large number of minute lenses having a positive refracting power arranged vertically and horizontally and densely. In general, a microlens array is formed by, for example, performing an etching process on a parallel flat plate to form a microlens group.
[0027]
Here, each micro lens constituting the micro lens array is smaller than each lens element constituting the fly-eye lens. Also, unlike a fly-eye lens composed of lens elements isolated from each other, the microlens array has a large number of microlenses (microrefractive surfaces) formed integrally without being isolated from each other. However, the microlens array is a wavefront splitting optical integrator similar to a fly-eye lens in that lens elements having positive refractive power are arranged vertically and horizontally. Note that, in FIG. 1, illustration of a minute refraction surface forming the microlens array 3 is omitted for clarity of the drawing.
[0028]
The light beam incident on the microlens array 3 is two-dimensionally divided by a large number of minute lenses, and a light source is formed on the rear focal plane of each minute lens on which the light beam has entered. In this way, a substantial surface light source (hereinafter, referred to as “secondary light source”) including a large number of light sources is formed on the rear focal plane of the microlens array 3. The luminous flux from the secondary light source formed on the rear focal plane of the microlens array 3 is restricted by an aperture stop (not shown) arranged as necessary, passes through a condenser optical system 4, and then passes through a reticle blind 5 Are superimposedly illuminated.
[0029]
In this way, a rectangular illumination field similar to the shape of each microlens constituting the microlens array 3 is formed on the reticle blind 5 as an illumination field stop. The light beam passing through the rectangular opening (light transmitting portion) of the reticle blind 5 receives the light-condensing action of the imaging optical system 6 and then superimposes the reticle (mask) R on which a predetermined pattern is formed. Light up. Thus, the imaging optical system 6 forms an image of the rectangular opening of the reticle blind 5 on the reticle R.
[0030]
The light beam transmitted through the pattern of the reticle R forms an image of the reticle pattern on the wafer W as a photosensitive substrate via the catadioptric projection optical system PL. As described above, the light source 1, the beam expander 2, the microlens array 3, the condenser optical system 4, the reticle blind 5, and the imaging optical system 6 constitute an illumination optical device for illuminating the reticle R. Further, the condenser optical system 4, the reticle blind 5, and the imaging optical system 6 constitute a light guiding optical system for guiding a light beam from the secondary light source to the reticle R. The specific configurations of the projection optical system PL and the imaging optical system 6 will be described later.
[0031]
In this manner, scan exposure is performed while driving and controlling the wafer W two-dimensionally in a plane (XY plane) orthogonal to the optical axis (projection optical axis) AXp of the projection optical system PL, so that each exposure area of the wafer W The pattern of the reticle R is exposed. In the scan exposure, a reticle pattern is transferred to each exposure region of the wafer W while the reticle R and the wafer W are relatively moved in the Y direction with respect to the projection optical system PL according to a step-and-scan method. In this case, the shape of the illumination region on the reticle R is a rectangular shape having a ratio of the short side to the long side of, for example, 1: 3, and the cross-sectional shape of each microlens of the microlens array 3 is a rectangular shape similar to this. It becomes.
[0032]
FIG. 2 is a diagram schematically illustrating the positional relationship between the illumination optical axis of the illumination optical device and the projection optical axis of the projection optical system and the configuration of the light transmission unit of the reticle blind in the present embodiment. FIG. 2A is a view of the reticle R viewed from the illumination optical devices (1 to 6), and the projection of the illumination optical axis AXi of the illumination optical device (1 to 6) and the projection optical system PL on the reticle R. The positional relationship with the optical axis AXp is shown. Referring to FIG. 2A, an illumination area IR formed on a reticle R arranged on the object plane of the projection optical system PL has a circular projection field centered on the projection optical axis AXp of the projection optical system PL. It has a rectangular shape elongated in the X direction in the IF, the dimension in the short side direction is Liy, and the dimension in the long side direction is Lix.
[0033]
The illumination region IR is eccentric in the Y direction from the projection optical axis AXp of the projection optical system PL and does not include the projection optical axis AXp. The illumination optical axis AXi of the illumination optical devices (1 to 6) coincides with the center of the illumination region IR. As a result, the illumination optical axis AXi of the illumination optical devices (1 to 6) is eccentric in the Y direction by the distance C (the amount of eccentricity C) with respect to the projection optical axis AXp of the projection optical system PL. In the illumination region IR on the reticle R, the distance from the illumination optical axis AXi at the position farthest from the illumination optical axis AXi is defined as Yi.
[0034]
On the other hand, referring to FIG. 2B, the reticle blind 5 as a field stop has a rectangular shape having a dimension in the short side direction Loy and a dimension in the long side direction Lox so as to optically correspond to the illumination region IR. (Light opening) 5a. In the light transmitting portion 5a of the reticle blind 5, the distance from the illumination optical axis AXi at the position farthest from the illumination optical axis AXi is defined as Yo. Although not shown, a rectangular stationary exposure area elongated in the X direction on the wafer W arranged on the image plane of the projection optical system PL so as to optically correspond to the illumination area IR. Is formed.
[0035]
FIG. 3 is a diagram schematically showing a specific configuration of the projection optical system according to the present embodiment. As shown in FIG. 3, the projection optical system PL according to the present embodiment includes a refraction-type first imaging optical system G1 for forming a first intermediate image of the pattern of the reticle R, a concave reflecting mirror CM, A second imaging optical system for forming a second intermediate image (substantially the same image of the first intermediate image and a secondary image of the reticle pattern) constituted by the negative lens 33 and the image of the first intermediate image; A system G2 and a refraction-type third imaging optical system G3 for forming a final image of the reticle pattern (a reduced image of the reticle pattern) on the wafer W based on light from the second intermediate image. .
[0036]
In the optical path between the first imaging optical system G1 and the second imaging optical system G2, near the formation position of the first intermediate image, the light from the first imaging optical system G1 is applied to the second imaging optical system. A reflecting surface (first optical path bending mirror) 31 for bending the optical path for deflecting by 90 ° toward the system G2 is arranged. Further, in the optical path between the second imaging optical system G2 and the third imaging optical system G3, near the formation position of the second intermediate image, the light from the second imaging optical system G2 is subjected to the third imaging. A reflection surface (second optical path bending mirror) 32 for deflecting by 90 ° toward the image optical system G3 is arranged.
[0037]
The first intermediate image and the second intermediate image are in the optical path between the first optical path bending mirror 31 and the second imaging optical system G2 and between the second imaging optical system G2 and the second optical path bending mirror 32. Each is formed in the optical path. Here, the reflecting surface of the first optical path bending mirror 31 and the reflecting surface of the second optical path bending mirror 32 are positioned so as not to spatially overlap. The third imaging optical system G3 converts a reduced image of the pattern of the reticle R (an image of the second intermediate image and a final image of the catadioptric optical system) on the photosensitive substrate based on the light beam from the second intermediate image. Formed on a wafer W as a substrate.
[0038]
The first imaging optical system G1 has an optical axis AX1 extending linearly, the third imaging optical system G3 has an optical axis AX3 extending linearly, and the optical axis AX1 and the optical axis AX3 are common. Are set to coincide with the projection optical axis AXp, which is the single reference optical axis. Note that the projection optical axis AXp is positioned along the direction of gravity (that is, the vertical direction). As a result, reticle R and wafer W are arranged parallel to each other along a plane orthogonal to the direction of gravity, that is, a horizontal plane. In addition, all lenses forming the first imaging optical system G1 and all lenses forming the third imaging optical system G3 are also arranged along the horizontal plane on the projection optical axis AXp.
[0039]
On the other hand, the second imaging optical system G2 also has an optical axis AX2 extending linearly, and this optical axis AX2 is set to be orthogonal to the projection optical axis AXp. Further, both the first optical path bending mirror 31 and the second optical path bending mirror 32 have a planar reflecting surface, and are integrally formed as one optical member (one optical path bending mirror FM) having two reflecting surfaces. ing. The line of intersection of these two reflecting surfaces (strictly, the line of intersection of the virtual extension surface) is AX1 of the first imaging optical system G1, AX2 of the second imaging optical system G2, and AX2 of the third imaging optical system G3. AX3 is set to intersect at one point. The first optical path bending mirror 31 and the second optical path bending mirror 32 are both configured as surface reflecting mirrors.
[0040]
In the above-described configuration, the chromatic aberration and the positive Petzval sum generated in the first imaging optical system G1 and the third imaging optical system G3, which are refractive optical systems including a plurality of lenses, are converted into the concave surface of the second imaging optical system G2. Compensation is performed by the reflecting mirror CM and the two negative lenses 33. Further, with the configuration in which the second imaging optical system G2 has substantially the same magnification, it is possible to form the second intermediate image near the first intermediate image. By performing optical path separation in the vicinity of these two intermediate images, the distance of the exposure area (that is, the effective exposure area) from the projection optical axis AXp, that is, the off-axis amount can be set small. This is advantageous not only in aberration correction, but also in miniaturization of the optical system, optical adjustment, mechanical design, manufacturing cost, and the like.
[0041]
FIG. 4 is a diagram schematically illustrating a specific configuration of the imaging optical system according to the present embodiment. Referring to FIG. 4, the imaging optical system 6 in the present embodiment has the parallel plane plate P1, the biconcave lens L61, and the aspherical convex surface directed to the light exit side in the order of incidence of light from the reticle blind 5. A positive meniscus lens L62, a positive meniscus lens L63 having a concave surface on the incident side, a positive meniscus lens L64 having a concave surface on the incident side, a biconvex lens L65, a first mirror M1, an aperture stop AS, and an exit side A bi-convex lens L66 having an aspherical convex surface directed to, a positive meniscus lens L67 having a convex surface directed to the incident side, a second mirror M2, and a positive meniscus lens L68 having an aspherical convex surface directed to the incident side; It is constituted by a parallel plane plate P2.
[0042]
All light transmitting members (lenses L61 to L68 and parallel plane plates P1 and P2) constituting the imaging optical system 6 are formed of quartz. The oscillation center wavelength of the ArF excimer laser light as the exposure light is 193.306 nm, and the refractive index of quartz with respect to the center wavelength of 193.306 nm is 1.5603261. The aspheric surface has a height y in a direction perpendicular to the illumination optical axis AXi, and a distance (sag amount) along an optical axis from a tangent plane at a vertex of the aspheric surface to a position on the aspheric surface at a height y. Is z, the vertex radius of curvature is r, the cone coefficient is κ, and the nth order aspherical coefficient is C_nIs expressed by the following equation (a). In the following Table (1), an asterisk is added to the right side of the surface number for a lens surface formed in an aspherical shape.
[0043]
(Equation 1)

[0044]
In the present embodiment, the biconcave lens L61 is a spherical lens, and is decentered from the illumination optical axis AXi by 1.048 mm in the direction of the arrow F1 in the figure along a direction optically corresponding to the Y direction on the reticle R. It constitutes the first adaptive optics element arranged. The positive meniscus lens L62 is an aspherical lens, and is disposed eccentrically from the illumination optical axis AXi by 6.749 mm in the direction of the arrow F2 in the figure along a direction optically corresponding to the Y direction on the reticle R. It constitutes a second adaptive optical element. The positive meniscus lens L64 is a spherical lens and is disposed eccentrically from the illumination optical axis AXi by 6.171 mm in the direction of arrow F3 in the figure along a direction optically corresponding to the Y direction on the reticle R. This constitutes a three-compensation optical element.
[0045]
The biconvex lens L66 is an aspheric lens, and is disposed eccentrically from the illumination optical axis AXi by 1.439 mm in the direction of the arrow F4 in the figure along a direction optically corresponding to the Y direction on the reticle R. Four compensating optical elements are configured. The positive meniscus lens L67 is a spherical lens, and is disposed eccentrically from the illumination optical axis AXi by 5.277 mm in the direction of arrow F5 in the figure along a direction optically corresponding to the Y direction on the reticle R. 5 compensating optical elements are configured. The positive meniscus lens L68 is an aspherical lens, and is disposed eccentrically from the illumination optical axis AXi by 5.371 mm in the direction of arrow F6 in the figure along a direction optically corresponding to the Y direction on the reticle R. This constitutes a sixth adaptive optical element.
[0046]
The following Table (1) lists values of specifications of the imaging optical system 6 according to the present embodiment. In the main specifications of Table (1), λ is the central wavelength of the exposure light, β is the imaging magnification, NA is the image-side (reticle-side) numerical aperture, and C is the illumination optical axis AXi with respect to the projection optical axis AXp. The eccentricity is shown respectively. Liy × Lix is the dimension of the short side direction × long side direction dimension of the illumination region IR, Yi is the maximum distance from the illumination optical axis AXi in the illumination region IR, and Loy × Lox is the light transmission portion 5 a of the reticle blind 5. Yo represents the dimension in the short side direction × the dimension in the long side direction, and Yo represents the maximum distance from the illumination optical axis AXi in the light transmitting portion 5a of the reticle blind 5.
[0047]
In the optical member specifications of Table (1), the surface number indicates the order of the optical surfaces from the reticle blind side, r indicates the radius of curvature of each optical surface (vertical radius of curvature: mm for an aspheric surface), d is the on-axis spacing of each optical surface, that is, the surface spacing (mm), φ is the effective diameter (diameter: mm) of each optical surface, n is the refractive index for the central wavelength of exposure light, and s is each compensation optical element. (A) shows the amount of eccentricity (mm) from the illumination optical axis AXi. The on-axis distance d between the optical surfaces indicates the on-axis distance in a state where each of the compensation optical elements is not decentered.
[0048]
[Table 1]
(Main specifications)
λ = 193.306 nm
β = 1.25
NA = 0.221
C = 22mm
Liy × Lix = 20 mm × 104 mm
Yi = 52.95mm
Loy × Lox = 16 mm × 83.2 mm
Yo = 42.36mm

(Aspherical data)
6 faces
κ = 0.000000
C₄= -9.241717 * 10^-9    C₆= −3.334312 × 10^-13
C₈= -1.36105 × 10^-16
16 faces
κ = 0.000000
C₄= 1.30933 × 10^-9    C₆= −1.0815 × 10^-15
C₈= 1.882834 × 10^-20
20 faces
κ = 0.000000
C₄= 4.0427 × 10^-9    C₆= 2.28047 × 10^-13
C₈= −1.43169 × 10^-17
[0049]
FIGS. 5 to 7 are diagrams showing lateral aberrations in the imaging optical system according to the present embodiment. Specifically, FIG. 5 shows a lateral aberration corresponding to a coordinate position of Y = 0% and X = 100% to 0% with respect to the illumination optical axis AXi in the rectangular illumination region IR formed on the reticle R surface. Is shown. FIG. 6 shows lateral aberrations corresponding to coordinate positions of Y = + 100% and X = 100% to 0% with respect to the illumination optical axis AXi in the rectangular illumination region IR formed on the reticle R surface. I have.
[0050]
FIG. 7 shows lateral aberrations corresponding to coordinate positions of Y = -100% and X = 100% to 0% with respect to the illumination optical axis AXi in the rectangular illumination region IR formed on the reticle R surface. ing. As is clear from the aberration diagrams, in the imaging optical system 6 of the present embodiment, the lateral aberration is favorably corrected. In the rectangular illumination region IR formed on the reticle R surface, the coordinates shown in FIG. 2A can be referred to for the coordinate position with the illumination optical axis AXi as the origin.
[0051]
In the present embodiment, the aspheric lenses L62, L66, and L68 are each configured such that a lens having an aspheric optical surface that is rotationally symmetric with respect to the illumination optical axis AXi is eccentrically arranged with respect to the illumination optical axis AXi. In other words, the aspheric lenses L62, L66, and L68 are lenses having an aspheric optical surface that is rotationally asymmetric with respect to the projection optical axis AXp. The eccentricity B of the rotation axis of the aspheric optical surface of the aspheric lens L62 from the illumination optical axis AXi is 6.749 mm, and the illumination light of the rotation axis of the aspheric optical surface of the aspheric lens L66. The eccentricity B from the axis AXi is 1.439 mm, and the eccentricity B of the rotation axis of the aspherical optical surface of the aspherical lens L68 from the illumination optical axis AXi is 5.371 mm.
[0052]
On the other hand, the eccentricity A of the spherical lens L61 from the illumination optical axis AXi is 1.048 mm, the eccentricity A of the spherical lens L64 from the illumination optical axis AXi is 6.171 mm, and the illumination optical axis AXi of the spherical lens L67. Is 5.277 mm. Further, referring to Table (1), the first compensation optical element closest to the reticle blind 5, that is, the axial distance Do from the spherical lens L61 to the reticle blind 5 is 58.224 mm, and the sixth compensation element closest to the reticle R is The axial distance Di from the optical element, that is, the aspheric lens L68 to the reticle R is 185.788 mm.
[0053]
FIG. 8 is a diagram schematically illustrating an error of the object side telecentricity of the projection optical system according to the present embodiment. In FIG. 8, the position of each principal ray passing within the range of the illumination area IR on the object plane (the pattern surface of the reticle R) of the projection optical system PL in the present embodiment, and a predetermined distance from the object plane of the projection optical system PL A line segment connecting the position of the principal ray passing through a predetermined parallel plane set parallel to the object plane on the wafer side is shown together with a line segment corresponding to the X-direction component and a line segment corresponding to the Y-direction component. ing. Note that the above description is also applied to the following corresponding FIGS. 9 and 10.
[0054]
If there is no error in the object side (reticle side) telecentricity in the projection optical system PL, there is no inclination of the principal ray with respect to the normal to the object plane, that is, there is no inclination of the principal ray with respect to the projection optical axis AXp or the illumination optical axis AXi. In FIG. 8, only points appear in a matrix. However, in practice, as shown in FIG. 8, each principal ray passing through the illumination region IR is positioned at the upper left end in the figure (X = −100% and Y = −100% with the illumination optical axis AXi as the origin). Except for the coordinate position) and the lower left position (coordinate position of X = + 100%, Y = −100% with the illumination optical axis AXi as the origin), the object-side telecentricity error is tilted toward the projection optical axis AXp. appear.
[0055]
Here, the error distribution of the object-side telecentricity of the projection optical system PL is symmetric with respect to the Y axis having the origin at the illumination optical axis AXi. Although the line segment corresponding to the inclination of 1 mrad of the principal ray is shown in the lower right of FIG. 8, the maximum error component in the X direction of the object side telecentricity in the projection optical system PL is 3.23 × 10^-3Radians, or 3.23 mrad, and the maximum error component in the Y direction is 3.46 mrad.
[0056]
FIG. 9 is a diagram schematically showing a telecentricity compensation operation by the imaging optical system according to the present embodiment. FIG. 10 is a diagram schematically illustrating a result of compensating an error of the object-side telecentricity of the projection optical system in the present embodiment by the imaging optical system. In the present embodiment, as shown in FIG. 9, six compensating optical elements (L61, L62, L64, L66, L67, L68) are used to compensate for an error in the object-side telecentricity of the projection optical system PL. In addition, an image-side (reticle-side) telecentricity error distribution having a tendency opposite to the object-side telecentricity error distribution of the projection optical system PL is given to the imaging optical system 6.
[0057]
Note that a line segment corresponding to a tilt of 1 mrad of the principal ray is shown in the lower right of FIG. 9, and the maximum error component in the X direction of the image side telecentricity in the imaging optical system 6 is 2.39 mrad, The maximum error component in the Y direction is 2.56 mrad. As a result, in the present embodiment, as shown in FIG. 10, an error of the object side telecentricity of the projection optical system PL is favorably compensated by the operation of the imaging optical system 6. A line segment corresponding to the inclination of 1 mrad of the principal ray is shown at the lower right of FIG. 10. The maximum error in the X direction of the object side telecentricity in the projection optical system PL compensated by the imaging optical system 6. The component is 0.85 mrad, and the maximum error component in the Y direction is 0.98 mrad.
[0058]
As described above, in the present embodiment, the illumination optical axis AXi does not coincide with the projection optical axis AXp, and the illumination optical axis AXp is eccentric in the Y direction to illuminate the center of the illumination region IR not including the projection optical axis AXp. Since the optical axis AXi is set so as to pass through, each of the optical elements constituting the illumination optical system does not increase in the radial direction, and thus the illumination optical devices (1 to 6) do not increase in size. In addition, since six compensating optical elements decentered in the optical path of the imaging optical system 6 are used, the compensating optical element is not mechanically interfered with the reticle blind 5, the reticle stage, and the alignment system. Also, even if the reticle R is sufficiently spaced from the reticle R, an error in the object-side telecentricity of the projection optical system PL can be favorably compensated without substantially causing distortion.
[0059]
Therefore, in the present embodiment, in the exposure apparatus that illuminates the illumination region IR that does not include the projection optical axis AXp of the catadioptric projection optical system PL, the optical elements constituting the illumination optical system are not enlarged in the radial direction ( That is, while reducing the size of the illumination optical devices (1 to 6)), the object-side telecentricity of the projection optical system is reduced by using compensating optical elements that are easily arranged while avoiding mechanical interference with other components. The error can be well compensated. As a result, in the present embodiment, high-resolution and high-precision projection is performed using compact illumination optical devices (1 to 6) that can favorably compensate for an error in the object-side telecentricity of the projection optical system PL. Exposure can be performed.
[0060]
In the above-described embodiment, the compensating optical element includes three spherical lenses L61, L64, and L67 eccentrically arranged with respect to the illumination optical axis AXi, and a rotation axis eccentric with respect to the illumination optical axis AXi (projection). Three aspheric lenses L62, L66, and L68 having an aspheric optical surface that is rotationally asymmetric with respect to the optical axis AXp). However, in general, a spherical lens that is decentered with respect to the illumination optical axis AXi, regardless of whether it is an aspheric lens having an aspheric optical surface that is rotationally asymmetric with respect to the projection optical axis AXp, By using at least two adaptive optics, it is possible to satisfactorily compensate for an error in the object side telecentricity of the projection optical system PL without substantially causing distortion.
[0061]
In this case, in order to further satisfactorily compensate for the error of the object side telecentricity of the projection optical system PL while further suppressing the occurrence of distortion, the pupil plane of the imaging optical system 6 (at or near the position of the aperture stop AS). Preferably, at least two adaptive optics are arranged on one side with respect to ()). For the same reason, when at least two compensating optical elements include two spherical lenses eccentrically arranged with respect to the illumination optical axis AXi, it is preferable that these two spherical lenses have different amounts of eccentricity A from each other. Furthermore, for the same reason, when at least two compensating optical elements include an aspheric lens, the aspheric optical surface of the aspheric lens has a reference axis (rotation axis) decentered from the illumination optical axis AXi and the projection optical axis AXp. It is preferable to have
[0062]
In the present invention, when at least two compensating optical elements include a spherical lens eccentrically arranged with respect to the illumination optical axis AXi, the amount of eccentricity A of the spherical lens from the illumination optical axis AXi is expressed by the following conditional expression (1). ) Is preferably satisfied.
A <C × 0.9 (1)
[0063]
In the present embodiment, the eccentricity A of the spherical lens L61 as the first compensating optical element is 1.048 mm, and the eccentricity A of the spherical lens L64 as the third compensating optical element from the illumination optical axis AXi is 6.171 mm. The eccentricity A of the spherical lens L67, which is the fifth compensation optical element, from the illumination optical axis AXi is 5.277 mm, and C × 0.9 is 22 × 0.9 = 19.8 mm. Therefore, in the present embodiment, each adaptive optics satisfies the conditional expression (1). In other words, by using at least two compensating optical elements, the amount of eccentricity A of the compensating optical element can be suppressed to the extent that conditional expression (1) can be satisfied.
[0064]
In the present invention, when at least two compensating optical elements include an aspheric lens having a rotation axis decentered with respect to the illumination optical axis AXi, the rotation axis of the aspherical optical surface of the aspheric lens in the aspheric lens is determined. The eccentric amount B from the illumination optical axis AXi preferably satisfies the following conditional expression (2).
B <C × 0.9 (2)
[0065]
In the present embodiment, the eccentricity B of the rotation axis of the aspherical optical surface of the aspheric lens L62, which is the second compensation optical element, from the illumination optical axis AXi is 6.749 mm, and is the fourth compensation optical element. The amount of eccentricity B of the rotation axis of the aspherical optical surface of the aspherical lens L66 from the illumination optical axis AXi is 1.439 mm, and the amount of eccentricity B of the aspherical optical surface of the aspherical lens L68 that is the sixth compensating optical element. The amount of eccentricity B of the rotation axis from the illumination optical axis AXi is 5.371 mm, and C × 0.9 is 22 × 0.9 = 19.8 mm. Therefore, in the present embodiment, each adaptive optics satisfies the conditional expression (2). In other words, by using at least two compensating optical elements, the amount of eccentricity B of the compensating optical element can be reduced to the extent that conditional expression (2) can be satisfied.
[0066]
In the present invention, it is preferable that the adaptive optics satisfies the following conditional expressions (3) and (4). In the conditional expressions (3) and (4), D is the axial distance Do from the compensation optical element closest to the reticle blind 5 to the reticle blind 5 and the axis from the compensation optical element closest to the reticle R to the reticle R. This is the smaller one of the upper distance Di.
D> Yo × 0.6 (3)
D> Yi × 0.6 (4)
[0067]
As described above, the first compensation optical element closest to the reticle blind 5, that is, the axial distance Do from the spherical lens L61 to the reticle blind 5 is 58.224 mm, and the sixth compensation optical element closest to the reticle R, that is, the aspheric surface The axial distance Di from the lens L68 to the reticle R is 185.788 mm. On the other hand, the maximum distance Yo from the illumination optical axis AXi in the light transmitting portion of the reticle blind 5 is 42.36 mm, and the maximum distance Yi from the illumination optical axis AXi in the illumination region IR is 52.95 mm.
[0068]
Therefore, while the distance D is Do = 58.224 mm, Yo × 0.6 is 42.36 × 0.6 = 25.416 mm, and Yi × 0.6 is 52.95 × 0.6 = 31.77 mm. As a result, in the present embodiment, the adaptive optics satisfies the conditional expressions (3) and (4). In other words, by using at least two compensating optical elements, the compensating optical elements are sufficiently spaced from the reticle R and the reticle blind 5 until the conditional expressions (3) and (4) can be satisfied. Can be arranged.
[0069]
Further, in the above-described embodiment, a plurality of compensating optical elements are arranged in the optical path of the imaging optical system 6. However, the present invention is not limited to this. For example, the microlens array 3 as an optical integrator and the reticle R A plurality of compensating optics can also be arranged in other suitable illumination light paths, such as in the light path between them.
[0070]
By the way, in the above-described embodiment, it is preferable to include an adjusting optical element for correcting an influence of a manufacturing error or a positioning error of the adaptive optical element. Here, as the adjusting optical element, a refractive optical element (lens) movable along the illumination optical axis AXi, a refractive optical element tiltable with respect to the illumination optical axis AXi, or a direction intersecting the illumination optical axis AXi. Refractive optics that can move along can be used.
[0071]
FIG. 11 is a diagram schematically illustrating a specific configuration of a projection optical system according to a first modification of the present embodiment. As shown in FIG. 11, a projection optical system PL in a first modification of the present embodiment is a catadioptric first imaging optical system for forming an intermediate image of a pattern formed on a reticle R as a projection master. A system G1 and a refraction-type second imaging optical system G2 for re-imaging an image of an intermediate image by the first imaging optical system G1 on a wafer (photosensitive substrate) W as a work. I have.
[0072]
Here, in the optical path between the reticle R and the first imaging optical system G1, a reflecting surface 41 for bending the optical path for deflecting the optical path by 90 ° is arranged. In the optical path between the first imaging optical system G1 and the second imaging optical system G2, that is, in the vicinity of the intermediate image, a reflecting surface 42 for bending the optical path for deflecting the optical path by 90 ° is disposed. Have been. These reflecting surfaces 41 and 42 are provided on the optical path bending member FM. Further, the first imaging optical system G1 has a plurality of lens components and a concave reflecting mirror CM arranged along the optical axis AX1, and forms an intermediate image under substantially equal or slightly reduced magnification. Form.
[0073]
The second imaging optical system G2 has a plurality of lens components arranged along an optical axis AX2 orthogonal to the optical axis AX1 and a variable aperture stop AS for controlling a coherence factor. , An intermediate image, that is, a secondary image, is formed at a reduced magnification. Here, the optical axis AX1 of the first imaging optical system G1 is bent by 90 ° by the reflecting surface 41 for bending the optical path, and defines the optical axis AX0 between the reticle R and the reflecting surface 41. In the present embodiment, the optical axis AX0 and the optical axis AX2 are parallel to each other, but do not coincide.
[0074]
In the first modification, one or a plurality of lens components may be arranged along the optical axis AX0. Further, the optical axis AX0 and the optical axis AX2 may be arranged so as to coincide with each other. Further, the angle between the optical axis AX0 and the optical axis AX1 may be an angle different from 90 °, preferably an angle obtained by rotating the concave reflecting mirror CM counterclockwise. At this time, it is preferable to set the bending angle of the optical axis on the reflection surface 42 so that the reticle R and the wafer W are parallel.
[0075]
FIG. 12 is a diagram schematically showing a specific configuration of a projection optical system according to a second modification of the present embodiment. As shown in FIG. 12, a projection optical system PL in a second modification of the present embodiment is a catadioptric first imaging optical system for forming an intermediate image of a pattern formed on a reticle R as a projection original. A system G1 and a refraction-type second imaging optical system G2 for forming the intermediate image formed by the first imaging optical system G1 on a wafer (photosensitive substrate) W as a workpiece. I have.
[0076]
In the optical path between the first imaging optical system G1 and the second imaging optical system G2, a reflecting surface 51 for bending the optical path for deflecting the optical path by 90 °, and for deflecting the optical path by 90 °. And a reflection surface 52 for bending the optical path. The first imaging optical system G1 has a plurality of lens components and a concave reflecting mirror CM arranged along the optical axis AX1, and converts the intermediate image of the reticle R into a first optical path bending mirror at substantially the same magnification or slightly reduced magnification. Formed in the vicinity of the reflecting surface 51 as the first.
[0077]
The second imaging optical system G2 has a plurality of lens components arranged along the optical axis AX2, and reduces an image of the intermediate image (secondary image) on the wafer W based on light from the intermediate image. Form at magnification. Here, since the reflection surface 51 and the reflection surface 52 are arranged at an angle so as to be orthogonal to each other, the optical axis AX1 of the first imaging optical system G1 and the optical axis AX2 of the second imaging optical system G2 are different from each other. The reticle R and the wafer W are parallel to each other. In the second modification, one or more lens components may be arranged along the optical axis AX3 in the optical path between the reflecting surfaces 51 and 52 for bending the optical path.
[0078]
In the exposure apparatus according to the above-described embodiment, a mask (reticle) is illuminated by an illumination optical device (illumination step), and a transfer pattern formed on the mask is exposed onto a photosensitive substrate using a projection optical system (exposure). Through the steps, a micro device (semiconductor element, imaging element, liquid crystal display element, thin film magnetic head, etc.) can be manufactured. Hereinafter, an example of a method for obtaining a semiconductor device as a micro device by forming a predetermined circuit pattern on a wafer or the like as a photosensitive substrate using the exposure apparatus of the present embodiment will be described with reference to the flowchart of FIG. Will be explained.
[0079]
First, in step 301 of FIG. 13, a metal film is deposited on one lot of wafers. In the next step 302, a photoresist is applied on the metal film on the l lot of wafers. Thereafter, in step 303, using the exposure apparatus of this embodiment, an image of the pattern on the mask is sequentially exposed and transferred to each shot area on the wafer of the lot through the projection optical system. After that, in step 304, the photoresist on the one lot of wafers is developed, and in step 305, the resist on the one lot of wafers is etched using the resist pattern as a mask to form a pattern on the mask. A corresponding circuit pattern is formed in each shot area on each wafer. Thereafter, a device such as a semiconductor element is manufactured by forming a circuit pattern of an upper layer and the like. According to the above-described semiconductor device manufacturing method, a semiconductor device having an extremely fine circuit pattern can be obtained with high throughput.
[0080]
In the exposure apparatus of the present embodiment, a liquid crystal display element as a micro device can be obtained by forming a predetermined pattern (circuit pattern, electrode pattern, etc.) on a plate (glass substrate). Hereinafter, an example of the technique at this time will be described with reference to the flowchart in FIG. 14, in a pattern forming step 401, a so-called photolithography step of transferring and exposing a mask pattern to a photosensitive substrate (a glass substrate coated with a resist) using the exposure apparatus of the present embodiment is performed. By this photolithography process, a predetermined pattern including a large number of electrodes and the like is formed on the photosensitive substrate. Thereafter, the exposed substrate undergoes each of a developing process, an etching process, a resist stripping process, and the like, whereby a predetermined pattern is formed on the substrate, and the process proceeds to the next color filter forming process 402.
[0081]
Next, in the color filter forming step 402, a large number of sets of three dots corresponding to R (Red), G (Green), and B (Blue) are arranged in a matrix, or three sets of R, G, B Are formed in a horizontal scanning line direction to form a color filter. Then, after the color filter forming step 402, a cell assembling step 403 is performed. In the cell assembly step 403, a liquid crystal panel (liquid crystal cell) is assembled using the substrate having the predetermined pattern obtained in the pattern formation step 401, the color filter obtained in the color filter formation step 402, and the like. In the cell assembling step 403, for example, a liquid crystal is injected between a substrate having a predetermined pattern obtained in the pattern forming step 401 and the color filter obtained in the color filter forming step 402, and a liquid crystal panel (liquid crystal cell) is formed. ) To manufacture.
[0082]
Thereafter, in a module assembling step 404, components such as an electric circuit and a backlight for performing a display operation of the assembled liquid crystal panel (liquid crystal cell) are attached to complete a liquid crystal display element. According to the above-described method for manufacturing a liquid crystal display device, a liquid crystal display device having an extremely fine circuit pattern can be obtained with high throughput.
[0083]
In the above embodiment, the ArF excimer laser light source is used. However, the present invention is not limited to this. For example, a KrF excimer laser light source that supplies light having a wavelength of 248 nm or an Fr that supplies light having a wavelength of 156 nm is used.₂Other suitable light sources such as excimer laser light sources can also be used. Further, in the above-described embodiment, the present invention has been described by taking as an example a projection exposure apparatus provided with an illumination optical device. However, the present invention is applied to a general illumination optical device for illuminating an irradiated surface other than a mask. Obviously you can.
[0084]
【The invention's effect】
As described above, according to the illumination optical apparatus of the present invention, in an exposure apparatus that illuminates an illumination area that does not include the projection optical axis of a catadioptric projection optical system, for example, at least two compensation units that are arranged eccentrically from the illumination optical axis By using the optical element, the optical element constituting the illumination optical system does not become large in the radial direction, that is, while making the illumination optical device compact, and easily avoiding mechanical interference with other parts. Using the disposed compensation optical element, an error in the object side telecentricity of the projection optical system can be favorably compensated.
[0085]
Therefore, in the exposure apparatus and the exposure method using the illumination optical apparatus according to the present invention, a high-resolution and high-resolution image is obtained by using a compact illumination optical apparatus capable of satisfactorily compensating for an error in the object side telecentricity of the projection optical system. Accurate projection exposure can be performed, and a good device can be manufactured with high accuracy.
[Brief description of the drawings]
FIG. 1 is a diagram schematically showing a configuration of an exposure apparatus including an illumination optical device according to an embodiment of the present invention.
FIG. 2 is a diagram schematically illustrating a positional relationship between an illumination optical axis of an illumination optical device and a projection optical axis of a projection optical system and a configuration of a light transmission unit of a reticle blind in the embodiment.
FIG. 3 is a diagram schematically showing a specific configuration of a projection optical system according to the embodiment.
FIG. 4 is a diagram schematically illustrating a specific configuration of an imaging optical system according to the present embodiment.
FIG. 5 is a diagram illustrating lateral aberrations corresponding to coordinate positions of Y = 0% and X = 100% to 0% with respect to an illumination optical axis as an origin in a rectangular illumination area formed on a reticle surface.
FIG. 6 is a diagram showing lateral aberrations corresponding to coordinate positions of Y = + 100% and X = 100% to 0% with respect to an illumination optical axis as an origin in a rectangular illumination area formed on a reticle surface.
FIG. 7 is a diagram illustrating lateral aberrations corresponding to coordinate positions of Y = −100% and X = 100% to 0% with respect to an illumination optical axis as an origin in a rectangular illumination area formed on a reticle surface.
FIG. 8 is a diagram schematically illustrating an error in the object side telecentricity of the projection optical system according to the present embodiment.
FIG. 9 is a diagram schematically illustrating a telecentricity compensation operation by the imaging optical system according to the present embodiment.
FIG. 10 is a diagram schematically showing a result obtained by compensating an error of the object side telecentricity of the projection optical system by the imaging optical system in the embodiment.
FIG. 11 is a diagram schematically showing a specific configuration of a projection optical system according to a first modification of the present embodiment.
FIG. 12 is a diagram schematically showing a specific configuration of a projection optical system according to a second modification of the present embodiment.
FIG. 13 is a flowchart of a method for obtaining a semiconductor device as a micro device.
FIG. 14 is a flowchart of a method for obtaining a liquid crystal display element as a micro device.
[Explanation of symbols]
1 light source
3 Micro lens array
4 Condenser optical system
5 Reticle blind (illumination field stop)
6 Imaging optical system
R reticle
PL projection optical system
W wafer
AXp projection optical axis
AXi illumination optical axis
L61 to L68 adaptive optics

Claims (15)

In an illumination optical device for illuminating a predetermined area that does not include the projection optical axis by being decentered in a predetermined direction from the projection optical axis of the projection optical system on the object plane of the catadioptric projection optical system,
The illumination optical device has an illumination optical axis passing through the center of the predetermined area,
Comprising two compensating optical elements for compensating for an error in the object-side telecentricity of the projection optical system,
The illumination optical device, wherein the two compensation optical elements are arranged eccentrically from the illumination optical axis along a direction optically corresponding to the predetermined direction. The illumination optical device according to claim 1, wherein the eccentric amounts of the two compensation optical elements from the illumination optical axis are different from each other. In an illumination optical device for illuminating a predetermined area that does not include the projection optical axis by being decentered in a predetermined direction from the projection optical axis of the projection optical system on the object plane of the catadioptric projection optical system,
The illumination optical device has an illumination optical axis passing through the center of the predetermined area,
Comprising two compensating optical elements for compensating for an error in the object-side telecentricity of the projection optical system,
One of the two compensation optical elements is disposed eccentrically from the illumination optical axis along a direction optically corresponding to the predetermined direction,
The illumination optical device, wherein the other of the two compensation optical elements has an aspheric optical surface that is rotationally asymmetric with respect to the illumination optical axis. In an illumination optical device for illuminating a predetermined area that does not include the projection optical axis by being decentered in a predetermined direction from the projection optical axis of the projection optical system on the object plane of the catadioptric projection optical system,
The illumination optical device has an illumination optical axis passing through the center of the predetermined area,
Comprising two compensating optical elements for compensating for an error in the object-side telecentricity of the projection optical system,
The illumination optical device, wherein the two adaptive optics have an aspheric optical surface that is rotationally asymmetric with respect to the illumination optical axis. The illumination optical device according to claim 3, wherein the aspherical shape that is rotationally asymmetric with respect to the illumination optical axis has a reference axis decentered from the illumination optical axis and the projection optical axis. A light source for supplying a light beam, and further comprising an optical integrator arranged in an optical path between the light source and the object surface to form a secondary light source based on the light beam from the light source,
The illumination optical device according to claim 1, wherein the two adaptive optics are arranged in an optical path between the optical integrator and the object plane. Further comprising a light guiding optical system for guiding the light flux from the secondary light source to the object plane,
The light guide optical system is disposed at a position optically conjugate with the object plane, and defines a field stop for defining the shape and size of an illumination area formed on the object plane, and light transmission of the field stop. Having an imaging optical system for forming an image of the portion on the object plane,
The illumination optical device according to claim 6, wherein the two compensation optical elements are arranged in an optical path of the imaging optical system. The illumination optical device according to claim 7, wherein the two adaptive optics are arranged on one side with respect to a pupil plane of the imaging optical system. When the amount of eccentricity of each of the compensating optical elements from the illumination optical axis is A and the amount of eccentricity of the illumination optical axis with respect to the projection optical axis is C,
A <C × 0.9
The illumination optical device according to claim 1, wherein the following condition is satisfied. The eccentricity of the one compensating optical element from the illumination optical axis is A, and the eccentricity of the rotation axis of the aspherical optical surface of the other compensating optical element from the illumination optical axis is B. When the eccentric amount of the illumination optical axis with respect to the optical axis is C,
A <C × 0.9
B <C × 0.9
The illumination optical device according to claim 3, wherein the following condition is satisfied. With respect to the two compensating optical elements, the amount of eccentricity of the rotation axis of the aspherical optical surface of each compensating optical element from the illumination optical axis is B, and the amount of eccentricity of the illumination optical axis with respect to the projection optical axis is C. and when,
B <C × 0.9
The illumination optical device according to any one of claims 4 to 8, wherein the following condition is satisfied. For the two compensating optical elements, the smaller one of the distance from each compensating optical element to the field stop and the distance from each compensating optical element to the object plane is D, The distance from the illumination optical axis at a position furthest from the illumination optical axis is Yo, and the distance from the illumination optical axis at a position furthest from the illumination optical axis in the predetermined area of the object plane is Yi. When
D> Yo × 0.6
D> Yi × 0.6
The illumination optical device according to any one of claims 7 to 11, wherein the following condition is satisfied. At least one of a refractive optical element movable along the illumination optical axis, a refractive optical element tiltable with respect to the illumination optical axis, and a refractive optical element movable along a direction intersecting the illumination optical axis. The illumination optical device according to any one of claims 1 to 12, further comprising one refractive optical element. An illumination optical device according to any one of claims 1 to 13, and a reflection type projection optical system for projecting and exposing a pattern of a mask arranged on the object plane onto a photosensitive substrate. An exposure apparatus comprising: A mask disposed on the object plane is illuminated via the illumination optical device according to claim 1, and a pattern formed on the illuminated mask is reflected by the reflection type projection optical system. An exposure method comprising exposing the photosensitive substrate through a photosensitive substrate.

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