JP3987350B2 - Laser illumination optical system and exposure apparatus, laser processing apparatus, and projection apparatus using the same - Google Patents

Description

【００２６】
尚、表１では平行平板１２ａ，１２ｃ，１２ｄの傾斜方向と厚さで変位量を決めているが、下記の表２のように平行平板１２ａ，１２ｃ，１２ｄの厚さを同じにして傾斜角を各々変えても良い。
【００２７】
【表２】

【００２８】
表１または表２に示す傾斜角と厚さの平行平板１２ａ，１２ｃ，１２ｄを用いて、レーザアレイ光の光路を変位させ、フライアイインテグレータ１３，１４，１５で被照射部１６を照明すると図６のような強度分布が得られる。すなわち第１フライアイレンズ１３の各アレイ（各レンズ部）への入射光プロファイルは図６のアレイ１〜アレイ４に示すような位相がずれた強度分布となるため、被照射部１６で積算されると照度が均一化される。ただし、合成された光の周辺部は均一では無いため図６の矢印で示す領域が被照射部となるように設計することで均一性を確保できる。
【００２９】
次に図７は請求項３に係る発明の第２の実施例を示すレーザ照明光学系の概略平面構成図である。このレーザ照明光学系は、レーザアレイ光源１１と、複数のホログラム素子４１ａ，４１ｃ，４１ｄと、フライアイインテグレータ１３，１４，１５で構成されており、１６は被照射部を示している。すなわち、図７に示す構成は、図４の構成の平行平板の代わりに、レーザアレイ光源１１とフライアイインテグレータ１３，１４，１５の間に複数のホログラム素子４１ａ，４１ｃ，４１ｄを配置し、複数のホログラム素子４１ａ，４１ｃ，４１ｄでフライアイレンズ１３，１４のアレイごとに入射されるレーザアレイ光を所定の距離だけ変位させる手段を構成したものである。尚、その他の構成は図４と同様である。
【００３０】
ホログラム素子４１ａ，４１ｃ，４１ｄは、例えば透明な平行平板の表裏にレリーフ型ホログラムを作製し、表側で回折された光を裏側のホログラムで再度回折させる構成である。また、ホログラム素子４１ａ，４１ｃ，４１ｄへの入射光軸と出射光軸が平行となるようにし、変位量は第１の実施例で示した値と同じとする。この第２の実施例の構成でも、被照射部１６での照度分布は図６のようになり、照度が均一化される。本実施例でホログラム素子４１ａ，４１ｃ，４１ｄは表裏にホログラムが設置されているが、入射光軸と出射光軸は平行にしなくても本発明の効果は得られる。従って、ホログラム素子は表裏のうちどちらか一方にホログラムを作製しても良い。
【００３１】
（実施例４）
次に請求項４に係る発明の実施例について説明する。
図８は請求項４に係る発明の一実施例を示すレーザ照明光学系の概略平面構成図である。このレーザ照明光学系は、レーザ発光部がアレイ状に配列されたレーザアレイ光源５１（例えば半導体レーザアレイ光源）と、コリメートレンズアレイ５２と、フライアイレンズのアレイごとに入射されるレーザアレイ光を所定の距離だけ変位させる手段１２と、フライアイインテグレータ１３，１４，１５で構成されており、１６は被照射部である。
【００３２】
フライアイインテグレータ１３，１４，１５の構成及び機能（動作）は実施例１と同様である。
変位手段１２は、一例として、実施例３の第１実施例と同様に複数の平行平板１２ａ，１２ｃ，１２ｄを用いた場合を図示しているが、その他にも、実施例３の第２実施例と同様の複数のホログラム素子を用いた変位手段であっても良い。
レーザアレイ光源５１から出射される各レーザ光は全角で１０〜３０°程度の広がり角で発散される。コリメートレンズアレイ５２はこれらの発散ビームを平行光束化させるように機能する。すなわちコリメートレンズアレイ５２は、レーザアレイ光源５１の発光部のアレイピッチと同じピッチでレンズがアレイ化されており、レーザアレイ光源５１の各々の発光部から発散されるレーザ光を、各々対応するレンズでコリメートして平行光束化させる。コリメートレンズアレイ５２で平行光束化されたレーザビームは変位手段１２によって所定のビームが所定の距離だけ変位される。
【００３３】
仮に、レーザアレイ光源５１のアレイ数が１６で、第１、第２フライアイレンズ１３，１４の光源アレイ方向に沿った分割数が４の場合には、第１フライアイレンズ１３の各アレイに図５と同様な４個のガウシアンプロファイルのアレイ光が入射される。従ってこのときの変位手段１２（例えば複数の平行平板１２ａ，１２ｃ，１２ｄ）による変位量は前述の表１または表２のようになり、実施例３で述べたように、第１フライアイレンズ１３の各アレイ（各レンズ部）への入射光プロファイルは図６のアレイ１〜アレイ４に示すような位相がずれた強度分布となるため、被照射部１６で積算されると照度が均一化される。
このように、光源５１をレーザアレイとしても、コリメートレンズアレイ５２と変位手段１２を用いることによって、フライアイレンズ１３，１４の分割数が光源のアレイ数の約数であるという条件でも、被照射部１６上での照度の均一化が可能である。
【００３４】
（実施例５）
次に請求項５に係る発明の実施例について説明する。
図９は請求項５に係る発明の一実施例を示す図であって、（ａ）はレーザ照明光学系の概略平面構成図、（ｂ）はレーザ照明光学系の概略側面構成図である。このレーザ照明光学系は、レーザ発光部がアレイ状に配列されたレーザアレイ光源５１（例えば半導体レーザアレイ光源）と、コリメートレンズアレイ５２と、レーザアレイ光を所定の距離だけ変位させる手段１２と、レーザアレイに直交方向の光束を均一化させるホログラム素子６１と、フライアイインテグレータ６３，６４，６５で構成されており、１６は被照射部である。尚、図９（ａ），（ｂ）にはコリメートレンズアレイ５２があるが、光源の広がり角が小さければ必ずしも必要ではない。また、変位手段１２は、一例として、実施例３の第１実施例と同様の複数の平行平板１２ａ，１２ｃ，１２ｄを用いた場合を図示しているが、その他にも、実施例３の第２実施例と同様のホログラム素子を用いることも可能である。
【００３５】
本実施例のフライアイインテグレータはフライアイレンズ６３，６４とコンデンサレンズ６５からなり、実施例１と同様にシリンドリカルレンズ系で構成されており機能も同様のものである。すなわち、第１及び第２のフライアイレンズ６３，６４はシリンドリカルレンズアレイであり、コンデンサレンズ６５はシリンドリカルレンズである。そして図９（ａ）の紙面内に平行な光束がフライアイインテグレータで均一化され、被照射部１６が均一照明される。図９（ａ）の紙面内の動作は実施例４で述べた動作と同様であり、第１フライアイレンズ６３に入射されるレーザアレイ光が変位手段１２によって所定の距離だけ変位され、被照射部１６に照射されるプロファイルの位相が適宜ずれるため、照度が均一化される。
【００３６】
次にレーザアレイに直交方向の光束を均一化させるホログラム素子６１について述べる。ホログラム素子６１は、透過型振幅格子、透過型位相格子または透過型ブレーズ格子等により構成され、それぞれフォトレジストに干渉縞を焼き付けたり、機械的にダイヤモンドカッターでガラス板等の基板表面に溝を刻線する等して作製することができる。このホログラム素子６１は、レーザアレイ光源５１から発散されるレーザ光束のうち、一方向（格子溝のピッチ方向）のみの強度分布を格子によって変換させる働きを有する。本実施例では、ホログラム素子６１の格子方向は図９（ａ）の紙面に平行で、格子ピッチはホログラム素子面内で異なっているので、レーザアレイに直交方向の光束を均一化させるように機能する。このホログラム素子６１の変調ピッチは、一例として図１０に示すような格子ピッチで実現される。このような変調ピッチにガウシアンプロファイルのレーザビームが入射されると、光束の中心付近が広がり、ビームの周辺が圧縮されて均一化強度になる。図９（ｂ）では光束の強度の強い光線は間隔を狭めて表しており、ホログラム素子６１によってレーザアレイ光源５１のレーザアレイに直交する方向の光線の方向が変わり、被照射部１６で均一な照度が得られる。尚、フライアイインテグレータ６３，６４，６５はシリンドリカルレンズ系で構成されているので、図９（ｂ）のように、照明光学系の側面側からフライアイインテグレータを見ると単なる平板にすぎず、レーザアレイ光源５１のレーザアレイに直交する方向の屈折作用は無い。
【００３７】
ホログラム素子６１によるレーザアレイに直交方向の光束の照度均一化の過程では、フライアイインテグレータ６３，６４，６５を用いて光束を分割し被照射部１６で重ね合わせるといった場合にも干渉縞発生は起こらない。すなわち、ホログラム素子６１により光束の密度（照度）を連続的に変えていくため干渉縞が出ない。このため、被照射部１６の照度均一性は良好となる。尚、図９（ａ）においては、フライアイインテグレータ６３，６４，６５を用いた光学系であるが、被照射部１６で重ね合わされる光どうしはレーザアレイ光源５１の別々の光共振部（レーザ発光部）から出射した光であるため干渉しない。
【００３８】
（実施例６）
次に請求項６に係る発明の実施例について説明する。
図１１は請求項６に係る発明の実施例を示す図であって、（ａ）はレーザ照明光学系の概略平面構成図、（ｂ）はレーザ照明光学系の概略側面構成図である。このレーザ照明光学系は、レーザ発光部がアレイ状に配列されたレーザアレイ光源５１（例えば半導体レーザアレイ光源）と、コリメートレンズアレイ５２と、レーザアレイ光を所定の距離だけ変位させる手段１２と、レーザアレイに直交方向の光束を均一化させるホログラム素子６１と、フライアイインテグレータ機能を有するホログラム素子６２で構成されており、１６は被照射部である。
【００３９】
本実施例のレーザ照明光学系は、図９に示した構成のレーザ照明光学系のフライアイインテグレータ（フライアイレンズとコンデンサレンズ）に代えて、該フライアイインテグレータと同じ機能を持つホログラム素子６２を用いたものであり、その他のレーザアレイ光源５１、コリメートレンズアレイ５２、変位手段１２、ホログラム素子６１の構成、動作は実施例５と同様であるので、これらの説明は省略する。
【００４０】
フライアイインテグレータとしてのホログラム素子６２は、図９（ａ）に示したフライアイレンズ系と同じ機能を持つので、図１１（ａ）に示すように例えば１６個の発光部を有するレーザアレイ光源５１に対してアレイ方向に４分割して用いるものとするなら、各領域からの回折光は被照射部１６の全面を照らすように偏向され、かつ、拡大（場合によっては縮小）される。また、図９に示したようなフライアイレンズ系に比べれば、少なくともフライアイレンズ間隔（第１フライアイレンズ６３から第２フライアイレンズ６４までの間隔）を縮めることができる。このため、光学系を小型にすることができる。
【００４１】
（実施例７）
次に請求項７に係る発明の実施例について説明する。
図１２は請求項７に係る発明の一実施例を示す露光装置の概略構成図であり、図中の符号１００はレーザアレイ光源（または半導体レーザアレイ光源）、１０１は実施例１〜６（請求項１〜請求項６）のうちのいずれか一つに記載の構成を用いたレーザ照明光学系、１０２は被照射部であるレチクル、１０３は投影レンズ、１０４は基板ステージである。
【００４２】
本実施例の露光装置では、レーザアレイ光源１００からのレーザアレイ光は、実施例１〜６（請求項１〜請求項６）のうちのいずれか一つに記載の構成を用いたレーザ照明光学系１０１によって被照射部であるレチクル１０２上で均一放射照度となる。
レチクル１０２は半導体デバイスの製作工程でウエハー上に回路パターンを露光するために使用される露光用マスクのことであり、レチクル１０２のパターンは投影レンズ１０３によって基板ステージ１０４上に置かれたウエハーに露光される。また、基板ステージ１０４で露光位置を調整し、ウエハーの所望の位置を露光する。
【００４３】
尚、レーザ照明光学系１０１として、実施例１〜４（請求項１〜４）のうちのいずれか一つで説明した構成のレーザ照明光学系を用いた場合には、レチクル面上で均一照明が可能であり、また、実施例５，６（請求項５，６）で説明したレーザ照明光学系を用いた場合には、レーザアレイ光源１００のアレイ直交方向の光束を変調ピッチのホログラム素子で均一化させるため、レチクル面上で干渉縞のでない均一照明で露光を行うことができる。従って、照明性能がよく高性能な露光装置を実現することができる。
【００４４】
（実施例８）
次に請求項８に係る発明の実施例について説明する。
図１３は請求項８に係る発明の一実施例を示すレーザ加工装置の概略構成図であり、図中の符号１００はレーザアレイ光源（または半導体レーザアレイ光源）、１０１は実施例１〜６（請求項１〜請求項６）のうちのいずれか一つに記載の構成を用いたレーザ照明光学系、１０５はレンズ、１０６はワークである。
【００４５】
本実施例のレーザ加工装置では、レーザアレイ光源１００からのレーザ光を実施例１〜６（請求項１〜請求項６）のうちのいずれか一つに記載のレーザ照明光学系で均一ビームに変換し、レンズ１０５でワーク１０６に縮小または拡大して照射される。集光スポットではワーク１０６の表面加工や切断加工ができる。また、レンズ１０５を投影レンズに置きかえるか、もしくは被照射部を直接ワークとする配置では、ワーク１０６の広い範囲にわたって均一照明できるため、レーザアニールとしても利用できる。
【００４６】
尚、レーザ照明光学系１０１として、実施例１〜４（請求項１〜４）のうちのいずれか一つで説明した構成のレーザ照明光学系を用いた場合には、ワーク上で均一照明でき、また、実施例５，６（請求項５，６）で説明したレーザ照明光学系を用いた場合には、レーザアレイ光源１００のアレイ直交方向の光束を変調ピッチのホログラム素子で均一化させるため、ワーク上で干渉縞が発生しない。このため、良好なレーザ加工やレーザアニールを行うことができる。
【００４７】
（実施例９）
次に請求項９に係る発明の実施例について説明する。
図１４は請求項９に係る発明の一実施例を示す投射装置の概略構成図である。本実施例の投射装置は、レーザアレイ光源１００ｒ，１００ｇ，１００ｂと、実施例１〜６（請求項１〜請求項６）のうちのいずれか一つに記載の構成を用いたレーザ照明光学系１１０ｒ、１１０ｇ、１１０ｂと、色合成手段１１３と、空間変調器（ライトバルブ）１１４と、投射レンズ１１５で構成されている。また、符号１１６はフィールドレンズで、ライトバルブ１１４からの画像光を効率良く投射レンズ瞳に入れるために用いるが、必ずしも必要ではない。尚、色合成手段１１３としてはダイクロイックプリズムやダイクロイックミラーを用いることができる。
【００４８】
本実施例では、レーザ照明光学系１１０ｒ、１１０ｇ、１１０ｂは、例えばホログラム素子１１１ｒ，１１１ｇ，１１１ｂとフライアイインテグレータ１１２ｒ，１１２ｇ，１１２ｂで構成されている。すなわち本実施例では、実施例５（または実施例６）で述べたような変調ピッチのホログラム素子１１１ｒ，１１１ｇ，１１１ｂでレーザアレイ光源１００ｒ，１００ｇ，１００ｂのアレイ直交方向の強度分布を変換し、アレイ方向はフライアイインテグレータ（フライアイレンズとコンデンサレンズ、あるいはフライアイインテグレータの機能を持つホログラム素子）１１２ｒ，１１２ｇ，１１２ｂで照度均一化させる。このレーザ照明光学系１１０ｒ、１１０ｇ、１１０ｂを使えば被照射部であるライトバルブ１１４面で干渉縞が発生しない。また、光源１００ｒ，１００ｇ，１００ｂとホログラム素子１１１ｒ，１１１ｇ，１１１ｂの間にコリメートレンズアレイを用いても良い。また、ホログラム素子１１１ｒ，１１１ｇ，１１１ｂを使用せず、フライアイインテグレータ１１２ｒ，１１２ｇ，１１２ｂでレーザアレイ光源１００ｒ，１００ｇ，１００ｂのアレイ方向とアレイ直交方向とを均一化させても良い。
【００４９】
レーザ照明光学系１１０ｒ、１１０ｇ、１１０ｂからの光束は色合成手段１１３に入射し、色合成手段１１３で赤（Ｒ）、緑（Ｇ）、青（Ｂ）の３色のレーザ光が合成される。この３色の合成光でライトバルブ１１４が照明され、ライドバルブ１１４で空間変調された画像は投射レンズ１１５でスクリーン（図示を省略）に投影される。ライトバルブ１１４としては例えば液晶素子を用いることができる。また、図１４では透過型のライトバルブを図示しているが、反射型のライトバルブを用いて照明光と投射光を偏光ビームスプリッタで分岐するように構成しても良い。
【００５０】
また、本実施例では単板のライトバルブ１１４を使っているが、３つのライトバルブを使うようにしても良い。図示しないが、３板式の場合には、一つのレーザアレイ光源とレーザ照明光学系の被照射部にライトバルブを配置し、３つのライトバルブからの画像光を色合成手段（例えばダイクロイックプリズム）で合成して投射レンズでスクリーンに投影させる。
【００５１】
本実施例の投射装置では、光源がレーザアレイ光源であるため、個々のレーザパワーが小さくてもアレイ数を多くすることにより高出力にできる。また、本実施例のように、レーザアレイ光源のレーザアレイ直交方向の光束を変調ピッチのホログラム素子１１１ｒ，１１１ｇ，１１１ｂで強度分布を変換させる場合、ライトバルブ１１４上で干渉縞の発生しない均一照明ができるため、明るくて表示品質の高い投射装置を実現することができる。
【００５２】
（実施例１０）
次に請求項１０に係る発明の実施例について説明する。
図１５は請求項１０に係る発明の一実施例を示す投射装置の概略構成図である。本実施例の投射装置は、レーザアレイ光源１００ｒ，１００ｇ，１００ｂと、実施例１〜６（請求項１〜請求項６）のうちのいずれか一つに記載の構成を用いたレーザ照明光学系（ホログラム素子１１１ｒ，１１１ｇ，１１１ｂ，フライアイインテグレータ１１２）と、色合成手段１１３と、ライトバルブ１１４と、投射レンズ１１５で構成されている。また、符号１１６はフィールドレンズで、ライトバルブ１１４からの画像光を効率良く投射レンズ瞳に入れるために用いるが、必ずしも必要ではない。尚、色合成手段１１３としては、ダイクロイックプリズムやダイクロイックミラーを用いることができる。
【００５３】
本実施例では、レーザ照明光学系は、三つのホログラム素子１１１ｒ，１１１ｇ，１１１ｂと一つのフライアイインテグレータ（例えばフライアイレンズ系、あるいはフライアイレンズ系の機能を有するホログラム素子）１１２からなるが、フライアイインテグレータ１１２は、色合成手段１１３で赤（Ｒ）、緑（Ｇ）、青（Ｂ）の３色のレーザ光を合成した後の光路に配置している。本実施例の構成によって、フライアイインテグレータ１１２が１組で足りるため装置の部品点数を減らすことができ、装置も小型にすることができる。
【００５４】
本実施例の投射装置では、光源がレーザアレイ光源であるため、個々のレーザパワーが小さくてもアレイ数を多くすることにより高出力にできる。また、本実施例のように、レーザアレイ光源のレーザアレイ直交方向の光束を変調ピッチのホログラム素子１１１ｒ，１１１ｇ，１１１ｂで強度分布を変換させる場合、ライトバルブ上で干渉縞の発生しない均一照明ができるため、明るくて表示品質の高い投射装置を実現することができる。さらに、本実施例では、フライアイインテグレータ１１２を共通化させたため、部品点数が少なくなり、低コストで小型の投射装置を実現することができる。
【００５５】
【発明の効果】
以上説明したように、請求項１記載のレーザ照明光学系では、複数の発光部を有するレーザアレイ光源と、フライアイレンズのレーザアレイ方向の分割数が前記複数の発光部の約数であるフライアイインテグレータを有するレーザ照明光学系であって、前記フライアイレンズのレンズに入射される前記発光部のレーザ光のプロファイルの空間的な位相をレンズ毎に異ならせることを特徴とするので、レーザアレイの周期構造とフライアイレンズの大きさを所定の条件にすることで、フライアイレンズの分割数がレーザアレイ光のアレイ数の約数の条件でも、被照射部での照度の均一化を図ることができる。
【００５６】
請求項２記載のレーザ照明光学系では、複数の発光部を有するレーザアレイ光源と、フライアイレンズを有するフライアイインテグレータを有するレーザ照明光学系であって、前記レーザアレイ光源の発光部は周期的に配置されており、前記レーザアレイ光源の発光部には、周期的に非点灯である発光部を有しており、前記フライアイレンズのレンズに入射される前記発光部のレーザ光のプロファイルの空間的な位相をレンズ毎に異ならせ、前記フライアイレンズのレーザアレイ方向の分割数は、前記発光部のうち点灯する発光部の約数であることにより、フライアイレンズの分割数がレーザアレイ光のアレイ数の約数の条件でも、被照射部での照度の均一化を図ることができる。
【００５７】
請求項３記載のレーザ照明光学系では、請求項１または２の構成に加えて、前記レーザアレイ光源と前記フライアイレンズの間に配置され該フライアイレンズのアレイごとに入射されるレーザアレイ光を所定の距離だけ変位させる手段を有することを特徴とするので、フライアイレンズに入射されるレーザアレイ光を変位手段で変位させることにより、フライアイレンズの分割数がレーザアレイ光のアレイ数の約数の条件でも、被照射部での照度の均一化を図ることができる。
【００５８】
請求項４記載のレーザ照明光学系では、複数の発光部を有するレーザアレイ光源と、コリメートレンズアレイと、フライアイレンズのレーザアレイ方向の分割数が発光部の約数であるフライアイインテグレータとを有し、前記フライアイレンズの所定のレンズに入射される前記発光部のレーザ光を変位させて、前記レーザ光のプロファイルの空間的な位相をレンズ毎に異ならせる手段を前記コリメートレンズと前記フライアイレンズとの間に配置したことを特徴とするので、フライアイレンズに入射されるレーザアレイ光を変位手段で変位させることにより、レーザアレイを用い且つフライアイレンズの分割数がレーザアレイ光のアレイ数の約数の条件でも、被照射部での照度の均一化を図ることができる。
【００５９】
請求項５記載のレーザ照明光学系では、請求項１，３または４の構成において、前記フライアイインテグレータはシリンドリカルレンズアレイとシリンダーレンズで構成され、レーザアレイに直交方向の光束は、光源とフライアイインテグレータの間に配置される変調ピッチのホログラム素子で均一化されることを特徴とするので、フライアイレンズに入射されるレーザアレイ光を変位させることで、フライアイレンズの分割数がレーザアレイ光のアレイ数の約数の条件でも、レーザアレイ方向の光束成分の照度を均一化ができ、レーザアレイに垂直方向は変調ピッチのホログラム素子で照度分布を変換し均一化を図るため、被照射部で干渉縞が出ず良好な照明が可能になる。
【００６０】
請求項６記載のレーザ照明光学系では、請求項１，３または４の構成において、前記フライアイインテグレータは、フライアイレンズに代えて同機能のホログラム素子で構成され、レーザアレイに直交方向の光束は、光源とフライアイインテグレータの間に配置される変調ピッチのホログラム素子で均一化されることを特徴とするので、請求項５と同様の効果が得られると共に、レーザアレイ方向の照度均一化と、アレイ直交方向の照度均一化を測る素子の両方をホログラム素子で構成するので、照明光学系を小さくすることが可能になる。
【００６１】
請求項７記載の露光装置では、請求項１〜６のいずれか一つに記載のレーザ照明光学系と、投影レンズを備えたことを特徴とするので、フライアイインテグレータのアレイ数がレーザアレイ数の約数の条件でも良好な照明が可能な露光装置を実現することができる。
【００６２】
請求項８記載のレーザ加工装置では、請求項１〜６のいずれか一つに記載のレーザ照明光学系と、レンズを備えたことを特徴とするので、フライアイインテグレータのアレイ数がレーザアレイ数の約数の条件でも良好な照明が可能なレーザ加工装置を実現することができる。
【００６３】
請求項９記載の投射装置では、請求項１〜６のいずれか一つに記載のレーザ照明光学系と、色合成手段と、空間変調器（ライトバルブ）と、投射レンズを備えたことを特徴とするので、フライアイインテグレータのアレイ数がレーザアレイ数の約数の条件でも良好な照明が可能で、色純度の高い投射装置を実現することができる。
【００６４】
請求項１０記載の投射装置では、請求項９の構成に加えて、色合成手段と空間変調器の間にフライアイインテグレータを配置したことを特徴とするので、フライアイインテグレータのアレイ数がレーザアレイ数の約数の条件でも良好な照明が可能で、色純度の高い投射装置を実現でき、さらに、複数の光源に対してフライアイインテグレータを一つに共通化させることができるので、部品点数を減らすことができ、低コストで小型な投射装置を実現することができる。
【図面の簡単な説明】
【図１】請求項１に係る発明の一実施例を示すレーザ照明光学系の概略平面構成図である。
【図２】請求項２に係る発明の一実施例を示すレーザ照明光学系の概略平面構成図である。
【図３】図１および図２に示すレーザ照明光学系の第１フライアイレンズに入射されるレーザアレイ光のプロファイルを示す図である。
【図４】請求項３に係る発明の第１の実施例を示すレーザ照明光学系の概略平面構成図である。
【図５】図４に示すレーザ照明光学系の第１フライアイレンズの一つのアレイ（レンズ部）に入射されるレーザアレイ光のプロファイルを示す図である。
【図６】図１、図２または図４に示すレーザ照明光学系のフライアイレンズの４分割された各アレイ（各レンズ部）を通過したレーザアレイ光（アレイ１〜４）の強度分布と被照射部１６上で加算された強度分布を示す図である。
【図７】請求項３に係る発明の第２の実施例を示すレーザ照明光学系の概略平面構成図である。
【図８】請求項４に係る発明の一実施例を示すレーザ照明光学系の概略平面構成図である。
【図９】請求項５に係る発明の一実施例を示す図であって、（ａ）はレーザ照明光学系の概略平面構成図、（ｂ）はレーザ照明光学系の概略側面構成図である。
【図１０】図９に示すレーザ照明光学系に用いられるホログラム素子のホログラム面の位置と格子ピッチの関係を示す図である。
【図１１】請求項６に係る発明の一実施例を示す図であって、（ａ）はレーザ照明光学系の概略平面構成図、（ｂ）はレーザ照明光学系の概略側面構成図である。
【図１２】請求項７に係る発明の一実施例を示す露光装置の概略構成図である。
【図１３】請求項８に係る発明の一実施例を示すレーザ加工装置の概略構成図である。
【図１４】請求項９に係る発明の一実施例を示す投射装置の概略構成図である。
【図１５】請求項１０に係る発明の一実施例を示す投射装置の概略構成図である。
【符号の説明】
１０，１１：レーザアレイ光源
１２：変位手段
１２ａ，１２ｃ，１２ｄ：変位手段を構成する平行平板
１３：第１フライアイレンズ
１４：第２フライアイレンズ
１５：コンデンサレンズ
１６：被照射部
４１ａ，４１ｃ，４１ｄ：変位手段を構成するホログラム素子
５１：レーザアレイ光源
５２：コリメートレンズアレイ
６１：変調ピッチのホログラム素子
６２：フライアイインテグレータ機能を有するホログラム素子
６３：第１フライアイレンズ（シリンドリカルレンズアレイ）
６４：第２フライアイレンズ（シリンドリカルレンズアレイ）
６５：コンデンサレンズ（シリンドリカルレンズ）
１００：レーザアレイ光源（または半導体レーザアレイ光源）
１００ｒ，１００ｇ，１００ｂ：レーザアレイ光源（または半導体レーザアレイ光源）
１０１：レーザ照明光学系
１０２：レチクル（露光用マスク）
１０３：投影レンズ
１０４：基板ステージ
１０５：レンズ
１０６：ワーク
１１０ｒ，１１０ｇ，１１０ｂ：レーザ照明光学系
１１１ｒ，１１１ｇ，１１１ｂ：ホログラム素子
１１２：フライアイインテグレータ
１１２ｒ，１１２ｇ，１１２ｂ：フライアイインテグレータ
１１３：色合成手段
１１４：空間変調器（ライトバルブ）
１１５：投射レンズ
１１６：フィールドレンズ[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a laser illumination optical system that uses a laser as a light source to make the illuminance at an irradiated portion uniform, and an exposure apparatus, a laser processing apparatus, and a projection apparatus using the same.
[0002]
[Prior art]
A projection apparatus using a laser as a light source is expected to project with high color purity because the oscillation spectrum of the laser is narrow. On the other hand, since the laser has high coherence, interference fringes may occur when the light beams are divided and then combined. For example, when a single laser beam is made uniform in illuminance by a normal fly-eye lens optical system, interference fringes are seen in the irradiated portion. Further, for example, in the hologram element described in Japanese Patent Application Laid-Open No. 8-94839, a configuration in which a part of the laser beam is superimposed on the irradiated portion to suppress interference is disclosed. Does not go away.
[0003]
On the other hand, a laser array light source (especially a semiconductor laser array light source) is expected as a laser light source with a relatively small size and high optical output. It is possible to constitute the laser illumination optical system. Further, when a laser array light source and a fly-eye lens are combined, the illuminance can be made uniform by selecting a number of divisions of the fly-eye lens other than a divisor of the number of laser arrays.
[0004]
However, when a number other than a divisor of the number of laser arrays is selected as the number of divisions of the fly-eye lens, the number may be large depending on the number of laser arrays. It was.
In other words, when combining a laser array light source and a fly-eye lens, etc., if the illuminance can be made uniform by dividing the fly-eye lens by a number that is a divisor of the number of laser arrays, the degree of freedom in designing the laser illumination optical system can be increased. Can be high.
[0005]
[Problems to be solved by the invention]
The present invention has been made in view of the above circumstances, and in a laser illumination optical system in which a laser array light source and a fly-eye lens are combined, the number of divisions of a fly-eye lens that has been difficult to achieve uniform illumination is conventionally a laser array. The object is to increase the illuminance uniformity at the irradiated portion when the number is a divisor.
[0006]
More specifically, the invention according to claims 1, 2 and 3 includes a laser array light source and a fly-eye lens, and the number of divisions of the fly-eye lens that has been difficult to achieve uniform illumination is conventionally lit. An object of the present invention is to provide a laser illumination optical system capable of improving the illuminance uniformity at the irradiated portion even when the number is a divisor.
Further, the invention according to claim 4 includes a semiconductor laser array light source and a fly-eye lens, and the number of divisions of the fly-eye lens that has been conventionally difficult to equalize illuminance is a divisor of the number of laser arrays that are turned on. Sometimes, it aims at providing the laser illumination optical system which can improve the illumination intensity uniformity of a laser array direction in an irradiated part.
[0007]
Furthermore, the invention according to claim 5 increases the illuminance uniformity in the laser array direction at the irradiated portion even when the number of divisions of the fly-eye lens, which has conventionally been difficult to achieve illuminance uniformity, is a divisor of the number of laser arrays. Another object of the present invention is to provide a laser illumination optical system that can reduce interference fringes caused by light beams in the array vertical direction of a laser array light source and improve the illumination performance to the irradiated portion.
Further, the invention according to claim 6 uses a hologram element instead of the fly-eye lens, and improves the illuminance uniformity in the laser array direction at the irradiated portion even when the number of divisions is a divisor of the number of laser arrays. A laser illumination optical system capable of reducing interference fringes caused by light beams in the vertical direction of the array of the laser array light source, improving the illumination performance to the irradiated part, and further reducing the size of the optical system The purpose is to provide.
[0008]
An object of the invention according to claim 7 is to provide an exposure apparatus in which the illumination optical system has a uniform illuminance and good illumination performance on a reticle or the like.
Another object of the present invention is to provide a laser processing apparatus in which the illumination optical system has uniform illuminance and high illuminance uniformity, and further a laser processing apparatus having no interference fringes.
Furthermore, the invention according to claim 9 is to provide a projection device in which the illumination optical system has a uniform illuminance and good illumination performance on the spatial modulator (light valve), and further a projection device in which no interference fringes are generated. And
In addition to the object of the ninth aspect, an object of the present invention is to provide a projection apparatus that can reduce the size of the illumination optical system.
[0009]
[Means for Solving the Problems]
In order to achieve the above object, the laser illumination optical system according to claim 1 comprises: Has multiple light emitting parts The number of divisions of the laser array light source and the fly-eye lens in the laser array direction is The plurality of light emitting units Fly eye integrator that is a divisor of Have A laser illumination optical system comprising: lens Incident on Laser light of the light emitting part Spatial phase of the profile Different for each lens It is characterized by this.
The laser illumination optical system according to claim 2 Has multiple light emitting parts With laser array light source Has a fly-eye lens Flyer good Integrator Have A laser illumination optical system, Said Laser array light source The light emitting units are periodically arranged, and the light emitting unit of the laser array light source includes Periodically It has a light emitting part that is not lit, Fly eye lens The spatial phase of the laser light profile of the light emitting unit incident on the lens is made different for each lens, and the fly-eye lens Number of divisions in the laser array direction Is the light emitting part to be lit among the light emitting parts. It is a divisor.
According to a third aspect of the present invention, in addition to the configuration of the first or second aspect, the laser illumination optical system is a laser that is disposed between the laser array light source and the fly eye lens and is incident on each fly eye lens array. It has means for displacing the array light by a predetermined distance.
[0010]
The laser illumination optical system according to claim 4, Has multiple light emitting parts The number of divisions of the laser array light source, collimating lens array, and fly-eye lens in the laser array direction is Of the light emitting part A fly eye integrator that is a divisor Have , Means for displacing the laser light of the light-emitting portion incident on a predetermined lens of the fly-eye lens to vary the spatial phase of the profile of the laser light for each lens, the collimating lens and the fly-eye lens Placed between It is characterized by this.
[0011]
According to a fifth aspect of the present invention, there is provided the laser illumination optical system according to the first, third, or fourth aspect, wherein the fly eye integrator includes a cylindrical lens array and a cylinder lens, and a light beam orthogonal to the laser array includes a light source and a fly eye. It is characterized by being made uniform by a hologram element having a modulation pitch arranged between integrators.
According to a sixth aspect of the present invention, there is provided the laser illumination optical system according to the first, third, or fourth aspect, wherein the fly eye integrator is configured by a hologram element having the same function instead of the fly eye lens, and is orthogonal to the laser array. The light flux is made uniform by a hologram element having a modulation pitch arranged between the light source and the fly eye integrator.
[0012]
An exposure apparatus according to a seventh aspect comprises the laser illumination optical system according to any one of the first to sixth aspects and a projection lens.
A laser processing apparatus according to an eighth aspect includes the laser illumination optical system according to any one of the first to sixth aspects and a lens.
[0013]
A projection apparatus according to a ninth aspect includes the laser illumination optical system according to any one of the first to sixth aspects, a color synthesis unit, a spatial modulator (light valve), and a projection lens. It is what.
According to a tenth aspect of the present invention, in addition to the configuration of the ninth aspect, a fly eye integrator is disposed between the color synthesizing means and the spatial modulator.
[0014]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the configuration, operation, and action of the laser illumination optical system and the exposure apparatus, laser processing apparatus, and projection apparatus using the laser illumination optical system according to the present invention will be described in detail based on the illustrated embodiments.
[0015]
Example 1
First, an embodiment of the invention according to claim 1 will be described.
FIG. 1 is a schematic plan view of a laser illumination optical system showing an embodiment of the invention according to claim 1. This laser illumination optical system includes a laser array light source 10 in which a plurality of light emitting portions are arranged in an array, a first fly-eye lens 13, a second fly-eye lens 14, and a condenser lens 15. A fly eye integrator having a number of divisions in the laser array direction that is a divisor of the number of laser arrays, and a plurality of laser beams oscillated from the laser array light source 10 are irradiated via the fly eye integrators 13 to 15. 16 is illuminated. The irradiated portion 16 is a portion irradiated with a uniform light beam, and an exposure mask (reticle) corresponds to the irradiated portion in the exposure apparatus, and a spatial light modulator (so-called light valve) corresponds to the irradiated portion in the projection apparatus. .
[0016]
As the laser array light source 10, a type in which laser oscillation units (light emitting units) such as semiconductor lasers are arranged in an array, a stripe type laser, or the like can be suitably used.
The first fly-eye lens 13 and the second fly-eye lens 14 constituting the fly-eye integrator are formed by arranging spherical or cylindrical lenses in an array shape in the same direction as the direction of the laser array. For example, from a cylindrical lens array Thus, the first fly-eye lens 13 functions to divide the incident light flux into light fluxes of the number of lens arrays and to collect the light on each lens of the second fly-eye lens 14. The second fly-eye lens 14 functions to refract the image condensed by the first fly-eye lens and collect the light flux on the irradiated portion 16 as much as possible.
[0017]
The condenser lens 15 arranged on the emission side optical path of the second fly's eye lens 14 of the fly eye integrator is composed of, for example, a cylindrical lens, and the condenser lens 15 makes the irradiated portion 16 arranged at a predetermined position more uniform. It is provided to illuminate the light, and by condensing the light emitted from the second fly-eye lens 14 on the irradiated portion 16, the light use efficiency can be increased and the unevenness in illuminance can be eliminated. The uniformity can be improved. That is, the light intensity in the lens array direction is made uniform by the first and second fly-eye lenses 13 and 14, but when there is no condenser lens 15, array light that does not illuminate the irradiated portion 16 is generated. Depending on how the array light overlaps in the irradiated portion 16, uneven illumination may occur. In the present embodiment, the first and second fly-eye lenses 13 are provided by the condenser lens (cylindrical lens) 15. , 14 is set so that the light beam in the lens array direction (laser array direction) is condensed on the irradiated portion 16, thereby realizing uniform illumination in the irradiated portion 16.
[0018]
In the present embodiment, the number of divisions in the laser array direction of the fly-eye lenses 13 and 14 constituting the fly-eye integrator is a divisor of the number of arrays of laser oscillation units (light emitting units) of the laser array light source 10. In the example of FIG. 1, the number of laser arrays is 16, and the number of divisions of the fly-eye lenses 13 and 14 in the laser array direction is 4. This is only an example, and other combinations may be used as long as a divisor relationship is established.
In this embodiment, the spatial phase of the profile of the laser array light incident on each array (each lens unit) of the fly-eye lenses 13 and 14 is different.
[0019]
Here, the arrangement of the light emitting portions of the laser array light source 10 and the relationship between the fly-eye lenses 13 and 14 will be described with reference to FIG. FIG. 3 shows a profile of the laser array light incident on the first fly-eye lens 13 of the laser illumination optical system shown in FIG. The laser light from each light emitting part of the laser array light source 10 has a Gaussian profile and four beam diameters are periodically arranged with P, and the following four are arranged with a gap of P. In other words, there are four laser profiles in a 5P period. Accordingly, the length of each array (each lens portion) of the first fly-eye lens 13 is 19P / 4. With such a configuration, the profile of the laser light incident on the first fly-eye lens 13 is shifted in phase by P / 4. Since the first fly-eye lens 13 and the irradiated portion 16 are in a conjugate relationship, the Gaussian profile array is added with a phase shift of P / 4 in the irradiated portion 16 as well. The intensity distribution of the laser array light (arrays 1 to 4) that has passed through each four-divided array (each lens part) of the fly-eye lens and the intensity distribution added on the irradiated part 16 are as shown in FIG. The illumination intensity on the irradiated portion 16 is made uniform.
[0020]
(Example 2)
Next, an embodiment of the invention according to claim 2 will be described.
FIG. 2 is a schematic plan view of a laser illumination optical system showing an embodiment of the invention according to claim 2. This laser illumination optical system includes a laser array light source 11 in which a plurality of light emitting units are arranged in an array, a first fly-eye lens 13, a second fly-eye lens 14, and a condenser lens 15. However, unlike the first embodiment, the laser array light source 11 is driven so that there is a light emitting portion that is not periodically turned on, although the intervals between adjacent lasers are all the same. That is, the laser array light source 11 includes non-lighting light emitting units arranged periodically. In FIG. 2, as an example, the five light emitting units 11 a to 11 e of the laser array light source 11 are set as one set, and one of the light emitting units 11 e is not lit. The fly eye lenses 13 and 14 are configured such that the number of divisions in the laser array direction is a divisor of the number of laser arrays to be lit, and a plurality of laser beams oscillated from the laser array light source 11 are transmitted to the fly eye integrators 13 to 13. 15 illuminates the irradiated portion 16. The irradiated portion 16 is a portion irradiated with a uniform light beam, and an exposure mask (reticle) corresponds to the irradiated portion in the exposure apparatus, and a spatial light modulator (so-called light valve) corresponds to the irradiated portion in the projection apparatus. .
As the laser array light source 11, a type in which laser oscillation units (light emitting units) such as lasers are arranged in an array, a stripe type laser, or the like can be suitably used.
Since the function of the fly eye integrator is the same as that described in the first embodiment, the description thereof is omitted.
[0021]
In the present embodiment, the laser light that is turned on by the laser array light source 11 is periodically arranged in a Gaussian profile with four beam diameters of P, and the following four are arranged with a gap of P. In other words, there are four laser profiles in a 5P period. Therefore, as shown in FIG. 3, the length of each array (each lens portion) of the first fly-eye lens 13 is 19P / 4. With such a configuration, the profile of the laser light incident on the first fly-eye lens 13 is shifted in phase by P / 4. Since the first fly-eye lens 13 and the irradiated portion 16 are in a conjugate relationship, the Gaussian profile array is added with a phase shift of P / 4 in the irradiated portion 16 as well. The intensity distribution of the laser array light (arrays 1 to 4) that has passed through each four-divided array (each lens part) of the fly-eye lens and the intensity distribution added on the irradiated part 16 are as shown in FIG. The illumination intensity on the irradiated portion 16 is made uniform.
[0022]
(Example 3)
Next, an embodiment of the invention according to claim 3 will be described.
FIG. 4 is a schematic plan view of a laser illumination optical system showing a first embodiment of the invention according to claim 3. This laser illumination optical system includes a laser array light source 11, a plurality of parallel plates 12a, 12c, and 12d, and fly eye integrators 13, 14, and 15, and 16 denotes an irradiated portion. That is, in the configuration shown in FIG. 4, in addition to the configuration of FIG. 1, a plurality of parallel plates 12a, 12c, and 12d made of a transparent member are arranged between the laser array light source 11 and the fly eye integrators 13, 14, and 15, A plurality of parallel plates 12a, 12c, and 12d constitute means for displacing the laser array light incident on each of the fly-eye lenses 13 and 14 by a predetermined distance. The configurations and functions (operations) of the fly eye integrators 13, 14, 15 are the same as those in the first embodiment.
[0023]
In the present embodiment, the number of laser arrays of the laser array light source 11 is 16 as in the first embodiment (FIG. 1), and the number of divisions of the first and second fly-eye lenses 13 and 14 in the laser array direction for explanation of the operation. Is 4. When configured with a normal fly-eye integrator, four laser array lights having a profile (intensity distribution) as shown in FIG. 5 are incident on one array (lens portion) of the first fly-eye lens 13. Since all the arrays (lens portions) of the first fly-eye lens 13 are incident with the light having the same profile as that in FIG. 5, the irradiated portion 16 accumulates four profiles in FIG. Irradiance unevenness occurs.
[0024]
Therefore, in this embodiment, as shown in FIG. 4, a plurality of parallel plates 12 a, 12 c, and 12 d are arranged between the laser array light source 11 and the first fly-eye lens 13, and are incident on each fly-eye lens 13 array. Means for displacing the laser array light by a predetermined distance is provided. Each parallel plate 12a, 12c, 12d constituting this displacement means is arranged at a predetermined inclination angle and has a predetermined thickness. For example, if one beam diameter P of the laser array light is 1 mm, the number of divisions of the fly-eye lens 13 is 4, so that the amount of light displacement by the parallel plates 12a, 12c, and 12d is 1/4 = 0.25. [Mm] each. As a specific example, parallel flat plates 12a, 12c, and 12d having an inclination angle and thickness as shown in Table 1 below are arranged. However, the refractive indexes of the parallel plates 12a, 12c, and 12d were 1.52.
[0025]
[Table 1]

[0026]
In Table 1, the amount of displacement is determined by the inclination direction and thickness of the parallel plates 12a, 12c, and 12d. However, as shown in Table 2 below, the parallel plates 12a, 12c, and 12d have the same thickness and the inclination angle is changed. May be changed.
[0027]
[Table 2]

[0028]
Using the parallel plates 12a, 12c, and 12d having the inclination angles and thicknesses shown in Table 1 or Table 2, the optical path of the laser array light is displaced, and the irradiated part 16 is illuminated by the fly eye integrators 13, 14, and 15 An intensity distribution like 6 is obtained. That is, the incident light profile to each array (each lens unit) of the first fly-eye lens 13 has an intensity distribution with a phase shift as shown in the arrays 1 to 4 in FIG. Then, the illuminance is made uniform. However, since the peripheral portion of the synthesized light is not uniform, the uniformity can be ensured by designing the region indicated by the arrow in FIG. 6 to be the irradiated portion.
[0029]
Next, FIG. 7 is a schematic plan view of a laser illumination optical system showing a second embodiment of the invention according to claim 3. This laser illumination optical system includes a laser array light source 11, a plurality of hologram elements 41a, 41c, and 41d, and fly eye integrators 13, 14, and 15, and 16 denotes an irradiated portion. That is, in the configuration shown in FIG. 7, a plurality of hologram elements 41a, 41c, 41d are arranged between the laser array light source 11 and the fly eye integrators 13, 14, 15 instead of the parallel plate of the configuration of FIG. The hologram elements 41a, 41c and 41d constitute means for displacing the laser array light incident for each array of fly-eye lenses 13 and 14 by a predetermined distance. Other configurations are the same as those in FIG.
[0030]
The hologram elements 41a, 41c, and 41d have a configuration in which, for example, a relief-type hologram is produced on the front and back sides of a transparent parallel plate, and light diffracted on the front side is diffracted again on the back side hologram. Further, the incident optical axis and the outgoing optical axis to the hologram elements 41a, 41c and 41d are made parallel to each other, and the displacement amount is the same as the value shown in the first embodiment. Even in the configuration of the second embodiment, the illuminance distribution in the irradiated portion 16 is as shown in FIG. 6, and the illuminance is made uniform. In this embodiment, the hologram elements 41a, 41c and 41d are provided with holograms on the front and back, but the effect of the present invention can be obtained even if the incident optical axis and the outgoing optical axis are not parallel. Therefore, the hologram element may produce a hologram on either the front or back side.
[0031]
(Example 4)
Next, an embodiment of the invention according to claim 4 will be described.
FIG. 8 is a schematic plan view of a laser illumination optical system showing an embodiment according to the fourth aspect of the present invention. This laser illumination optical system receives laser array light incident on each array of laser array light sources 51 (for example, semiconductor laser array light sources) in which laser light emitting sections are arranged in an array, a collimator lens array 52, and fly-eye lenses. It comprises means 12 for displacing by a predetermined distance, and fly eye integrators 13, 14, and 15. Reference numeral 16 denotes an irradiated portion.
[0032]
The configurations and functions (operations) of the fly eye integrators 13, 14, and 15 are the same as those in the first embodiment.
As an example, the displacing means 12 uses a plurality of parallel plates 12a, 12c, and 12d as in the first embodiment of the third embodiment, but the second embodiment of the third embodiment is also shown. Displacement means using a plurality of hologram elements similar to the example may be used.
Each laser beam emitted from the laser array light source 51 is diverged at a spread angle of about 10 to 30 ° in all angles. The collimating lens array 52 functions to make these divergent beams into parallel beams. That is, the collimating lens array 52 is an array of lenses at the same pitch as the array pitch of the light emitting portions of the laser array light source 51, and the laser light emitted from each light emitting portion of the laser array light source 51 is converted into a corresponding lens. Collimate with to make parallel light flux. The laser beam converted into a parallel beam by the collimating lens array 52 is displaced by a predetermined distance by the displacing means 12.
[0033]
If the number of arrays of the laser array light sources 51 is 16, and the number of divisions along the light source array direction of the first and second fly-eye lenses 13 and 14 is 4, each array of the first fly-eye lenses 13 The array light of four Gaussian profiles similar to FIG. 5 is incident. Accordingly, the displacement amount by the displacement means 12 (for example, the plurality of parallel flat plates 12a, 12c, 12d) at this time is as shown in Table 1 or Table 2 described above. As described in the third embodiment, the first fly-eye lens 13 The incident light profile to each array (each lens unit) has an intensity distribution that is out of phase as shown in array 1 to array 4 in FIG. The
As described above, even when the light source 51 is a laser array, even when the number of divisions of the fly-eye lenses 13 and 14 is a divisor of the number of light source arrays by using the collimating lens array 52 and the displacement means 12, The illuminance on the portion 16 can be made uniform.
[0034]
(Example 5)
Next, an embodiment of the invention according to claim 5 will be described.
FIGS. 9A and 9B are diagrams showing an embodiment of the invention according to claim 5, wherein FIG. 9A is a schematic plan view of a laser illumination optical system, and FIG. 9B is a schematic side view of the laser illumination optical system. The laser illumination optical system includes a laser array light source 51 (for example, a semiconductor laser array light source) in which laser light emitting units are arranged in an array, a collimator lens array 52, a means 12 for displacing the laser array light by a predetermined distance, It is composed of a hologram element 61 for uniformizing light beams in an orthogonal direction on the laser array and fly eye integrators 63, 64, 65, and 16 is an irradiated portion. Although FIGS. 9A and 9B show the collimator lens array 52, this is not always necessary if the light source has a small spread angle. Further, as an example, the displacing means 12 uses a plurality of parallel plates 12a, 12c, and 12d similar to those of the first embodiment of the third embodiment. It is also possible to use the same hologram element as in the second embodiment.
[0035]
The fly eye integrator according to the present embodiment includes fly eye lenses 63 and 64 and a condenser lens 65, and is configured by a cylindrical lens system as in the first embodiment and has the same function. That is, the first and second fly-eye lenses 63 and 64 are cylindrical lens arrays, and the condenser lens 65 is a cylindrical lens. Then, parallel light beams in the plane of FIG. 9A are made uniform by the fly eye integrator, and the irradiated portion 16 is illuminated uniformly. 9A is the same as the operation described in the fourth embodiment, and the laser array light incident on the first fly-eye lens 63 is displaced by a predetermined distance by the displacing means 12 to be irradiated. Since the phase of the profile irradiated to the part 16 is appropriately shifted, the illuminance is made uniform.
[0036]
Next, a description will be given of the hologram element 61 that makes the light flux in the orthogonal direction uniform on the laser array. The hologram element 61 is composed of a transmission type amplitude grating, a transmission type phase grating, a transmission type blaze grating, or the like. Each of the hologram elements 61 bakes interference fringes on the photoresist, or mechanically engraves grooves on the substrate surface such as a glass plate with a diamond cutter. It can be produced by wire or the like. The hologram element 61 has a function of converting the intensity distribution of only one direction (the pitch direction of the grating grooves) of the laser beam emitted from the laser array light source 51 by the grating. In this embodiment, the grating direction of the hologram element 61 is parallel to the paper surface of FIG. 9A, and the grating pitch is different within the hologram element surface, so that the laser array functions to make the light flux in the orthogonal direction uniform. To do. As an example, the modulation pitch of the hologram element 61 is realized by a grating pitch as shown in FIG. When a Gaussian profile laser beam is incident on such a modulation pitch, the vicinity of the center of the light beam spreads, and the periphery of the beam is compressed to a uniform intensity. In FIG. 9B, the light beam having a high intensity is shown with a narrower interval, and the direction of the light beam orthogonal to the laser array of the laser array light source 51 is changed by the hologram element 61 so that it is uniform in the irradiated portion 16. Illuminance can be obtained. Since the fly eye integrators 63, 64, and 65 are configured by a cylindrical lens system, as shown in FIG. 9B, when the fly eye integrator is viewed from the side of the illumination optical system, it is merely a flat plate. There is no refraction effect in the direction perpendicular to the laser array of the array light source 51.
[0037]
In the process of uniforming the illuminance of the light beam orthogonal to the laser array by the hologram element 61, interference fringes are generated even when the light beam is divided using the fly eye integrators 63, 64, 65 and superimposed on the irradiated portion 16. Absent. That is, since the density (illuminance) of the light beam is continuously changed by the hologram element 61, no interference fringes appear. For this reason, the illuminance uniformity of the irradiated portion 16 is good. In FIG. 9A, an optical system using fly eye integrators 63, 64, 65 is used, but the light superimposed on the irradiated portion 16 is separated from the separate optical resonators (lasers) of the laser array light source 51. Since it is light emitted from the light emitting part), it does not interfere.
[0038]
(Example 6)
Next, an embodiment of the invention according to claim 6 will be described.
11A and 11B are diagrams showing an embodiment of the invention according to claim 6, wherein FIG. 11A is a schematic plan configuration diagram of a laser illumination optical system, and FIG. 11B is a schematic side configuration diagram of the laser illumination optical system. The laser illumination optical system includes a laser array light source 51 (for example, a semiconductor laser array light source) in which laser light emitting units are arranged in an array, a collimator lens array 52, a means 12 for displacing the laser array light by a predetermined distance, It is composed of a hologram element 61 for uniformizing light beams in the orthogonal direction on the laser array and a hologram element 62 having a fly eye integrator function, and 16 is an irradiated portion.
[0039]
The laser illumination optical system of the present embodiment replaces the fly eye integrator (fly eye lens and condenser lens) of the laser illumination optical system having the configuration shown in FIG. 9 with a hologram element 62 having the same function as the fly eye integrator. Since the other laser array light source 51, collimating lens array 52, displacement means 12, and hologram element 61 are configured and operated in the same manner as in the fifth embodiment, description thereof will be omitted.
[0040]
Since the hologram element 62 as a fly eye integrator has the same function as the fly eye lens system shown in FIG. 9A, a laser array light source 51 having, for example, 16 light emitting portions as shown in FIG. However, if the light is divided into four in the array direction, the diffracted light from each region is deflected so as to illuminate the entire surface of the irradiated portion 16 and is enlarged (or reduced in some cases). Compared with the fly-eye lens system as shown in FIG. 9, at least the fly-eye lens interval (the interval from the first fly-eye lens 63 to the second fly-eye lens 64) can be reduced. For this reason, an optical system can be reduced in size.
[0041]
(Example 7)
Next, an embodiment of the invention according to claim 7 will be described.
FIG. 12 is a schematic block diagram of an exposure apparatus showing an embodiment of the invention according to claim 7. In FIG. 12, reference numeral 100 denotes a laser array light source (or semiconductor laser array light source), and 101 denotes examples 1 to 6 (invoices). A laser illumination optical system using the configuration according to any one of claims 1 to 6, 102 is a reticle that is an irradiated portion, 103 is a projection lens, and 104 is a substrate stage.
[0042]
In the exposure apparatus of the present embodiment, the laser array light from the laser array light source 100 is laser illumination optics using the configuration described in any one of Embodiments 1 to 6 (claims 1 to 6). The system 101 provides uniform irradiance on the reticle 102 which is the irradiated portion.
The reticle 102 is an exposure mask used to expose a circuit pattern on a wafer in a semiconductor device manufacturing process, and the pattern of the reticle 102 is exposed to a wafer placed on a substrate stage 104 by a projection lens 103. Is done. Further, the exposure position is adjusted by the substrate stage 104 to expose a desired position of the wafer.
[0043]
When the laser illumination optical system having the configuration described in any one of the first to fourth embodiments (claims 1 to 4) is used as the laser illumination optical system 101, uniform illumination is performed on the reticle surface. In addition, when the laser illumination optical system described in the fifth and sixth embodiments (Claims 5 and 6) is used, the light beam in the array orthogonal direction of the laser array light source 100 is converted by a hologram element having a modulation pitch. In order to make uniform, exposure can be performed with uniform illumination without interference fringes on the reticle surface. Therefore, it is possible to realize an exposure apparatus with good illumination performance and high performance.
[0044]
(Example 8)
Next, an embodiment of the invention according to claim 8 will be described.
FIG. 13 is a schematic configuration diagram of a laser processing apparatus showing an embodiment of the invention according to claim 8. In FIG. 13, reference numeral 100 denotes a laser array light source (or semiconductor laser array light source), and 101 denotes the first to sixth embodiments. A laser illumination optical system using the configuration according to any one of claims 1 to 6, 105 is a lens, and 106 is a workpiece.
[0045]
In the laser processing apparatus of the present embodiment, the laser light from the laser array light source 100 is converted into a uniform beam by the laser illumination optical system according to any one of the first to sixth embodiments (claims 1 to 6). Then, the work is reduced or enlarged by the lens 105 and irradiated. Surface processing and cutting of the workpiece 106 can be performed at the focused spot. Further, in the case where the lens 105 is replaced with a projection lens or the portion to be irradiated is directly used as a workpiece, uniform illumination can be performed over a wide range of the workpiece 106, so that it can be used for laser annealing.
[0046]
In addition, when the laser illumination optical system having the configuration described in any one of Examples 1 to 4 (Claims 1 to 4) is used as the laser illumination optical system 101, uniform illumination can be performed on the workpiece. When the laser illumination optical system described in Examples 5 and 6 (Claims 5 and 6) is used, the light beam in the array orthogonal direction of the laser array light source 100 is made uniform by a hologram element having a modulation pitch. No interference fringes occur on the workpiece. For this reason, good laser processing and laser annealing can be performed.
[0047]
Example 9
Next, an embodiment of the invention according to claim 9 will be described.
FIG. 14 is a schematic configuration diagram of a projection apparatus showing an embodiment of the invention according to claim 9. The projection apparatus of the present embodiment is a laser illumination optical system using the configuration described in any one of the laser array light sources 100r, 100g, and 100b and Embodiments 1 to 6 (claims 1 to 6). 110r, 110g, 110b, a color synthesizing unit 113, a spatial modulator (light valve) 114, and a projection lens 115. Reference numeral 116 denotes a field lens, which is used to efficiently put image light from the light valve 114 into the projection lens pupil, but is not always necessary. A dichroic prism or a dichroic mirror can be used as the color synthesizing unit 113.
[0048]
In the present embodiment, the laser illumination optical systems 110r, 110g, and 110b are configured by, for example, hologram elements 111r, 111g, and 111b and fly eye integrators 112r, 112g, and 112b. That is, in this embodiment, the intensity distribution in the array orthogonal direction of the laser array light sources 100r, 100g, and 100b is converted by the hologram elements 111r, 111g, and 111b having the modulation pitch as described in the fifth embodiment (or the sixth embodiment), The array direction is made uniform in illuminance by fly eye integrators (fly eye lenses and condenser lenses, or hologram elements having functions of fly eye integrators) 112r, 112g, and 112b. If the laser illumination optical systems 110r, 110g, and 110b are used, no interference fringes are generated on the surface of the light valve 114 that is the irradiated portion. A collimating lens array may be used between the light sources 100r, 100g, and 100b and the hologram elements 111r, 111g, and 111b. Further, without using the hologram elements 111r, 111g, and 111b, the array directions of the laser array light sources 100r, 100g, and 100b and the array orthogonal direction may be made uniform by the fly eye integrators 112r, 112g, and 112b.
[0049]
The light beams from the laser illumination optical systems 110r, 110g, and 110b are incident on the color synthesizing unit 113, and the color synthesizing unit 113 synthesizes laser beams of three colors of red (R), green (G), and blue (B). . The light valve 114 is illuminated with the combined light of these three colors, and the image spatially modulated by the ride valve 114 is projected onto a screen (not shown) by the projection lens 115. As the light valve 114, for example, a liquid crystal element can be used. Further, although a transmission type light valve is illustrated in FIG. 14, it may be configured such that illumination light and projection light are branched by a polarization beam splitter using a reflection type light valve.
[0050]
In this embodiment, the single plate light valve 114 is used, but three light valves may be used. Although not shown, in the case of a three-plate type, a light valve is disposed in the irradiated portion of one laser array light source and the laser illumination optical system, and image light from the three light valves is color-synthesized (for example, dichroic prism). Combine and project on the screen with a projection lens.
[0051]
In the projection apparatus of the present embodiment, since the light source is a laser array light source, high output can be achieved by increasing the number of arrays even if the individual laser power is small. Further, as in the present embodiment, when the intensity distribution is converted by the hologram elements 111r, 111g, and 111b having the modulation pitch with the light beams in the laser array orthogonal direction of the laser array light source, uniform illumination without generating interference fringes on the light valve 114 is performed. Therefore, a bright and high display quality projection device can be realized.
[0052]
(Example 10)
Next, an embodiment of the invention according to claim 10 will be described.
FIG. 15 is a schematic configuration diagram of a projection apparatus showing an embodiment of the invention according to claim 10. The projection apparatus of the present embodiment is a laser illumination optical system using the configuration described in any one of the laser array light sources 100r, 100g, and 100b and Embodiments 1 to 6 (claims 1 to 6). (Hologram elements 111r, 111g, 111b, fly eye integrator 112), color synthesizing means 113, light valve 114, and projection lens 115. Reference numeral 116 denotes a field lens, which is used to efficiently put image light from the light valve 114 into the projection lens pupil, but is not always necessary. As the color composition unit 113, a dichroic prism or a dichroic mirror can be used.
[0053]
In this embodiment, the laser illumination optical system includes three hologram elements 111r, 111g, and 111b and one fly-eye integrator (for example, a fly-eye lens system or a hologram element having a fly-eye lens system function) 112. The fly eye integrator 112 is arranged in the optical path after the color combining unit 113 combines the laser beams of the three colors red (R), green (G), and blue (B). With the configuration of this embodiment, since one set of fly eye integrators 112 is sufficient, the number of parts of the apparatus can be reduced, and the apparatus can also be reduced in size.
[0054]
In the projection apparatus of the present embodiment, since the light source is a laser array light source, high output can be achieved by increasing the number of arrays even if the individual laser power is small. Further, as in the present embodiment, when the intensity distribution is converted by the hologram elements 111r, 111g, and 111b having a modulation pitch with the light beams in the laser array orthogonal direction of the laser array light source, uniform illumination without interference fringes is generated on the light valve. Therefore, it is possible to realize a projection device that is bright and has high display quality. Further, in this embodiment, since the fly eye integrator 112 is made common, the number of parts is reduced, and a small projection device can be realized at low cost.
[0055]
【The invention's effect】
As described above, in the laser illumination optical system according to claim 1, Has multiple light emitting parts The number of divisions of the laser array light source and the fly-eye lens in the laser array direction is The plurality of light emitting units Fly eye integrator that is a divisor of Have A laser illumination optical system comprising: lens Incident on Laser light of the light emitting part Spatial phase of the profile Different for each lens By setting the periodic structure of the laser array and the size of the fly-eye lens to predetermined conditions, even if the number of fly-eye lens divisions is a divisor of the number of laser array light arrays, It is possible to make the illuminance uniform in the part.
[0056]
In the laser illumination optical system according to claim 2, Has multiple light emitting parts With laser array light source Has a fly-eye lens Flyer good Integrator Have A laser illumination optical system, Said Laser array light source The light emitting units are periodically arranged, and the light emitting unit of the laser array light source includes Periodically It has a light emitting part that is not lit, Fly eye lens The spatial phase of the laser light profile of the light emitting unit incident on the lens is made different for each lens, and the fly-eye lens Number of divisions in the laser array direction Is the light emitting part to be lit among the light emitting parts. By being a divisor, the illuminance at the irradiated portion can be made uniform even when the number of divisions of the fly-eye lens is a divisor of the number of laser array light arrays.
[0057]
In the laser illumination optical system according to claim 3, in addition to the configuration of claim 1 or 2, the laser array light disposed between the laser array light source and the fly eye lens and incident on each fly eye lens array Since the laser array light incident on the fly-eye lens is displaced by the displacement means, the number of fly-eye lens divisions is equal to the number of laser array light arrays. Even under divisor conditions, it is possible to make the illuminance uniform in the irradiated portion.
[0058]
In the laser illumination optical system according to claim 4, Has multiple light emitting parts The number of divisions of the laser array light source, collimating lens array, and fly-eye lens in the laser array direction is Of the light emitting part A fly eye integrator that is a divisor Have , Means for displacing the laser light of the light-emitting portion incident on a predetermined lens of the fly-eye lens to vary the spatial phase of the profile of the laser light for each lens, the collimating lens and the fly-eye lens Placed between Since the laser array light incident on the fly-eye lens is displaced by the displacing means, the laser array is used and the number of fly-eye lens divisions is a divisor of the array number of the laser array light. Thus, it is possible to make the illuminance uniform in the irradiated portion.
[0059]
According to a fifth aspect of the present invention, in the laser illumination optical system according to the first, third, or fourth aspect, the fly eye integrator includes a cylindrical lens array and a cylinder lens. Since it is uniformized by a hologram element having a modulation pitch arranged between the integrators, the number of divisions of the fly-eye lens can be reduced by displacing the laser array light incident on the fly-eye lens. The illumination intensity of the luminous flux component in the laser array direction can be made uniform even under the condition of a divisor of the number of arrays, and in the direction perpendicular to the laser array, the illuminance distribution is converted and made uniform by a hologram element having a modulation pitch. Therefore, no interference fringes appear and good illumination becomes possible.
[0060]
7. The laser illumination optical system according to claim 6, wherein the fly-eye integrator is constituted by a hologram element having the same function in place of the fly-eye lens in the configuration of claim 1, 3 or 4, and the light beam orthogonal to the laser array. Is uniformized by a hologram element having a modulation pitch arranged between the light source and the fly-eye integrator. Therefore, the same effect as in the fifth aspect can be obtained, and the illuminance can be made uniform in the laser array direction. Since both of the elements for measuring the illuminance uniformity in the array orthogonal direction are composed of hologram elements, the illumination optical system can be made small.
[0061]
The exposure apparatus according to claim 7 is provided with the laser illumination optical system according to any one of claims 1 to 6 and a projection lens, so that the number of fly-eye integrators is the number of laser arrays. It is possible to realize an exposure apparatus that can perform satisfactory illumination even under the condition of the divisor.
[0062]
Since the laser processing apparatus according to claim 8 is provided with the laser illumination optical system according to any one of claims 1 to 6 and a lens, the number of fly eye integrators is the number of laser arrays. Thus, it is possible to realize a laser processing apparatus capable of satisfactory illumination even under the condition of a few divisors.
[0063]
According to a ninth aspect of the present invention, there is provided a projection apparatus comprising the laser illumination optical system according to any one of the first to sixth aspects, a color synthesizing unit, a spatial modulator (light valve), and a projection lens. Therefore, even when the number of fly-eye integrator arrays is a divisor of the number of laser arrays, it is possible to achieve good illumination and to realize a projection apparatus with high color purity.
[0064]
According to a tenth aspect of the present invention, in addition to the configuration of the ninth aspect, a fly eye integrator is disposed between the color synthesizing means and the spatial modulator. Good illumination is possible even under divisor conditions, a projection device with high color purity can be realized, and a fly eye integrator can be shared for multiple light sources, so the number of parts can be reduced. A small projection device can be realized at low cost.
[Brief description of the drawings]
FIG. 1 is a schematic plan view of a laser illumination optical system showing an embodiment of the invention according to claim 1;
FIG. 2 is a schematic plan view of a laser illumination optical system showing an embodiment of the invention according to claim 2;
3 is a diagram showing a profile of laser array light incident on a first fly-eye lens of the laser illumination optical system shown in FIGS. 1 and 2. FIG.
4 is a schematic plan view of a laser illumination optical system showing a first embodiment of the invention according to claim 3; FIG.
5 is a view showing a profile of laser array light incident on one array (lens portion) of the first fly-eye lens of the laser illumination optical system shown in FIG. 4. FIG.
6 is an intensity distribution of laser array light (arrays 1 to 4) that has passed through each of the four divided arrays (each lens unit) of the fly-eye lens of the laser illumination optical system shown in FIG. 1, FIG. 2, or FIG. It is a figure which shows the intensity distribution added on the to-be-irradiated part.
7 is a schematic plan view of a laser illumination optical system showing a second embodiment of the invention according to claim 3. FIG.
8 is a schematic plan view of a laser illumination optical system showing an embodiment of the invention according to claim 4; FIG.
9A and 9B are diagrams showing an embodiment of the invention according to claim 5, wherein FIG. 9A is a schematic plan configuration diagram of a laser illumination optical system, and FIG. 9B is a schematic side configuration diagram of a laser illumination optical system. .
10 is a diagram showing the relationship between the position of the hologram surface of the hologram element used in the laser illumination optical system shown in FIG. 9 and the grating pitch.
11A and 11B are diagrams showing an embodiment of the invention according to claim 6, wherein FIG. 11A is a schematic plan configuration diagram of a laser illumination optical system, and FIG. 11B is a schematic side configuration diagram of the laser illumination optical system. .
12 is a schematic block diagram of an exposure apparatus showing an embodiment of the invention according to claim 7. FIG.
FIG. 13 is a schematic configuration diagram of a laser processing apparatus showing one embodiment of the invention according to claim 8;
14 is a schematic configuration diagram of a projection apparatus showing an embodiment of the invention according to claim 9. FIG.
FIG. 15 is a schematic configuration diagram of a projection apparatus showing an embodiment of the invention according to claim 10;
[Explanation of symbols]
10, 11: Laser array light source
12: Displacement means
12a, 12c, 12d: parallel flat plates constituting the displacement means
13: First fly-eye lens
14: Second fly-eye lens
15: Condenser lens
16: Irradiated part
41a, 41c, 41d: Hologram elements constituting displacement means
51: Laser array light source
52: Collimating lens array
61: Hologram element with modulation pitch
62: Hologram element having fly eye integrator function
63: First fly-eye lens (cylindrical lens array)
64: Second fly-eye lens (cylindrical lens array)
65: Condenser lens (cylindrical lens)
100: Laser array light source (or semiconductor laser array light source)
100r, 100g, 100b: Laser array light source (or semiconductor laser array light source)
101: Laser illumination optical system
102: Reticle (mask for exposure)
103: Projection lens
104: Substrate stage
105: Lens
106: Work
110r, 110g, 110b: Laser illumination optical system
111r, 111g, 111b: hologram element
112: Fly eye integrator
112r, 112g, 112b: fly eye integrator
113: Color composition means
114: Spatial modulator (light valve)
115: Projection lens
116: Field lens

Claims (10)

A laser illumination optical system having a laser array light source having a plurality of light emitting units and a fly eye integrator in which the number of divisions of the fly eye lens in the laser array direction is a divisor of the plurality of light emitting units ,
Laser illumination optical system characterized by varying the spatial phase of the profile of the laser beam of the light emitting portion is incident on the lens of the fly-eye lenses for each lens. A laser array light source having a plurality of light emitting portions, a laser illumination optical system having a Furaia good integrators having a fly-eye lens,
The light emitting section of the laser array light source is periodically arranged, and the light emitting section of the laser array light source has a light emitting section that is periodically not lit, and is incident on the lens of the fly-eye lens. The spatial phase of the laser light profile of the light emitting unit is different for each lens, and the number of divisions of the fly-eye lens in the laser array direction is a divisor of the light emitting units to be lit among the light emitting units. A featured laser illumination optical system. The laser illumination optical system according to claim 1 or 2,
A laser illumination optical system comprising means for displacing laser array light disposed between the laser array light source and the fly-eye lens and incident on each fly-eye lens array by a predetermined distance. A laser array light source having a plurality of light emitting portions has a collimating lens array, the number of divided laser array direction of the fly's eye lens and a fly-eye integrator is a submultiple of the light emitting portion, a predetermined lens of the fly-eye lens A means for displacing the laser light of the light emitting portion incident on the lens to vary the spatial phase of the profile of the laser light for each lens is disposed between the collimating lens and the fly-eye lens. Laser illumination optical system. The laser illumination optical system according to claim 1, 3 or 4,
The fly eye integrator is composed of a cylindrical lens array and a cylinder lens, and light beams orthogonal to the laser array are made uniform by a hologram element having a modulation pitch arranged between the light source and the fly eye integrator. Laser illumination optical system. The laser illumination optical system according to claim 1, 3 or 4,
The fly eye integrator is composed of a hologram element having the same function instead of the fly eye lens, and the light beam orthogonal to the laser array is made uniform by a hologram element having a modulation pitch arranged between the light source and the fly eye integrator. A laser illumination optical system.   An exposure apparatus comprising the laser illumination optical system according to claim 1 and a projection lens.   A laser processing apparatus comprising: the laser illumination optical system according to claim 1; and a lens.   A projection apparatus comprising the laser illumination optical system according to claim 1, a color synthesis unit, a spatial modulator, and a projection lens.   10. The projection apparatus according to claim 9, wherein a fly eye integrator is disposed between the color synthesizing means and the spatial modulator.

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