JP2004271552A - Enlarging and projecting optical system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an enlarging and projecting optical system coping with the larger screen of a display in spite of simple constitution, preventing the lowering of throughput and cost rise in the production of a mask, and having excellent image forming performance. <P>SOLUTION: The enlarging and projecting optical system for enlarging and projecting a pattern on an object surface to an image surface has a 1st lens group having at least one positive lens, a 1st mirror arranged nearly at the conjugate point of a pupil formed by the 1st lens group, a 2nd mirror arranged on the object surface side at a distance from the 1st mirror and reflecting a light beam from the 1st mirror to the image surface side, and a 2nd lens group arranged nearer to the image surface side than the 2nd mirror, forming the image on the image surface with the light beam from the 2nd mirror and having at least one positive lens in optical path order from the object surface side, and the effective image surface area contributing to projection is a circular-arc shaped area out of an axis in which the center of an optical axis is not included. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

【００２８】
数式１は、本発明が適用される像面ＩＭ側の開口数ＮＡを規定するものであり、主に液晶ディスプレイをターゲットにするにはこの範囲であることが好ましい。下限を超えると解像力が不足し、上限を超えると光束幅が大きくなるためにレンズ径が増大するなどして良くない。
【００２９】
本発明の投影光学系１００は、倍率をβとしたとき、以下の数式２で示す条件式を満足することが好ましい。
【００３０】
【数２】

【００３１】
数式２は、本発明が適用される光学系の倍率βを規定するものであり、下限を超えると、物体高が低くなると同時に、物体面ＭＳ側の開口数ＮＡが大きくなり光束幅も大きくなるので、光線と、ミラーやレンズを干渉させずに光学系を形成するのが困難になってくる。上限を超えると、物体高が高くなってくるので、マスクが大型化しマスク作製コストを低減することが難しくなってくる。
【００３２】
なお、本発明で構成されるミラーは、球面ミラーでも、非球面ミラーでも良い。また、レンズも非球面レンズとすることが、収差補正上、有効であり、レンズ枚数を削減することができる。さらに、色収差を補正する手段として、２種類以上の硝材を使用したり、色消しレンズを使用したりすることもできる。好ましくは、倍率色収差を補正する上では、相対的に正屈折力を有する第１のレンズ群Ｇ１の分散が、正屈折力を有する第２のレンズ群Ｇ２の分散より大きくなるようにガラスを選択すると良い。
【００３３】
さらに、光学系全体としてペッツバール項の和がゼロ又はゼロ近傍となるようにそのミラー形状、レンズパワーを決定するのが良い。
【００３４】
なお、本発明で使用される非球面のミラー及びレンズの形状は、以下の数式３に示す一般的な非球面の式であらわされる。
【００３５】
【数３】

【００３６】
数式３において、Ｚは光軸方向の座標、ｃは曲率（曲率半径ｒの逆数）、ｈは光軸からの高さ、ｋは円錐係数、Ａ、Ｂ、Ｃ、Ｄ、Ｅ、Ｆ、Ｇ、Ｈ、Ｊ、・・・は各々、４次、６次、８次、１０次、１２次、１４次、１６次、１８次、２０次、・・・の非球面係数である。
【００３７】
なお、本発明では、第１のミラーＭ１の近傍に図示しない開口絞りを設けても良い。開口絞りの径は、固定であっても可変であってもよい。可変の場合には、開口絞りの径を変化させることにより、光学系の開口数を変化させることができる。開口絞りを可変とすることで、深い焦点深度を得られるなどの長所が得られ、これによりさらに像を安定させることができる。
【００３８】
ここで、図２に示す本発明の反射屈折型拡大投影光学系１００Ａを用いて照明実験した結果について説明する。図２において、ＭＳは物体面位置に置かれたマスク、ＩＭは像面位置に置かれたガラス基板を示している。
【００３９】
反射屈折型拡大投影光学系１００Ａにおいて、波長３６５．０ｎｍ付近の光を放射する図示しない照明系によりマスクＭＳが照明され、マスクＭＳからの透過光が、第１のレンズ群Ｇ１を通り、距離を隔てて正レンズ群ＧＰ、第２のミラーＭ２（凸面鏡）、正レンズ群ＧＰと通過し、最後に第２のレンズ群Ｇ２により像面位置に置かれたガラス基板ＩＭ上に、マスクパターンの拡大像を形成している。なお、本実施形態では、正レンズ群ＧＰが第１のレンズ群Ｇ１の一部を兼用しており、光線が３回通る構成としている。
【００４０】
図２に示す反射屈折型拡大投影光学系１００Ａにおいて、ＮＡ＝０．０８、拡大倍率＝２倍、物高＝１５０ｍｍ乃至３００ｍｍ、像高＝３００ｍｍ乃至６００ｍｍの３００ｍｍ幅の円弧状像面である。ここで、図２の反射屈折型拡大投影光学系１００Ａの数値（曲率半径、面間隔、屈折率）を表１に、非球面係数を表２に示す。
【００４１】
【表１】

【００４２】
【表２】

【００４３】
図２に示す反射屈折型拡大投影光学系１００Ａの製造誤差を含まない収差（像高の数点で計算）は、波面収差＝０．０３２λｒｍｓ、歪曲最大値＝６７ｎｍであり、これは、波長３６５ｎｍでのｄｉｆｆｒａｃｔｉｏｎ ｌｉｍｉｔｅｄ（回折限界）な光学系であり、ターゲット解像力を３μｍとした場合でも十分な性能を有している。なお、光学系の全長は２２６６ｍｍ、最大有効径は第２のレンズ群Ｇ２でφ１３４９ｍｍとなっている。
【００４４】
以上のように、本発明の反射屈折型拡大投影光学系１００Ａは、非常に簡素な構成ながら回折限界の性能を達成し、且つ、収差補正された像面幅が大きい光学系となっている。
【００４５】
以下、図３を参照して、本発明の反射屈折型拡大投影光学系１００Ａを適用した露光装置２００を説明する。図３は、反射屈折型拡大投影光学系１００Ａを有する露光装置２００を示す概略構成図である。図３を参照するに、露光装置２００は、照明装置２１０と、マスクＭＳと、マスクステージ２２０と、反射屈折型拡大投影光学系１００Ａと、被処理体ＩＭと、ステージ２３０と、制御部２４０とを有する。
【００４６】
本発明の露光装置２００は、例えば、スキャン露光方式でマスクＭＳに形成されたパターンを被処理体ＩＭに露光する投影露光装置である。かかる露光装置は、例えば、４０インチ相当の大画面液晶ディスプレイの製造に好適である。ここで、「スキャン露光方式」とは、マスク上のパターンの一部をマスクと基板を同期走査することによりマスクパターン全体を露光する露光方法である。
【００４７】
照明装置２１０は、転写用のパターンが形成されたマスクＭＳを照明し、光源部２１２と、照明光学系２１４とを有する。
【００４８】
光源部２１２は、例えば、光源としてレーザーを使用する。レーザーは、波長約１９３ｎｍのＡｒＦエキシマレーザー、波長約２４８ｎｍのＫｒＦエキシマレーザー、波長約１５３ｎｍのＦ_２レーザーなどを使用することができるが、レーザーの種類は限定されず、例えば、ＹＡＧレーザーを使用してもよいし、そのレーザーの個数も限定されない。例えば、独立に動作する２個の固体レーザーを使用すれば固体レーザー間相互のコヒーレンスはなく、コヒーレンスに起因するスペックルはかなり低減する。さらにスペックルを低減するために光学系を直線的又は回転的に揺動させてもよい。また、光源部２１２にレーザーが使用される場合、レーザー光源からの平行光束を所望のビーム形状に整形する光束整形光学系、コヒーレントなレーザー光束をインコヒーレント化するインコヒーレント化光学系を使用することが好ましい。また、光源部２１２に使用可能な光源はレーザーに限定されるものではなく、一又は複数の水銀ランプやキセノンランプなどのランプも使用可能である。
【００４９】
照明光学系２１４は、マスクＭＳを照明する光学系であり、レンズ、ミラー、ライトインテグレーター、絞り等を含む。例えば、コンデンサーレンズ、ハエの目レンズ、開口絞り、コンデンサーレンズ、スリット、結像光学系の順で整列する等である。照明光学系２１４は、軸上光、軸外光を問わず使用することができる。ライトインテグレーターは、ハエの目レンズや２組のシリンドリカルレンズアレイ（又はレンチキュラーレンズ）板を重ねることによって構成されるインテグレーター等を含むが、光学ロッドや回折素子に置換される場合もある。
【００５０】
マスクＭＳは、反射型又は透過型マスクで、その上には転写されるべきパターン（又は像）が形成され、マスクステージ２２０に支持及び駆動される。マスクＭＳは、反射屈折型拡大投影光学系１００Ａによって、従来に比べて小型化することができる。マスクＭＳから発せられた回折光は、反射屈折型拡大投影光学系１００Ａを通り、被処理体ＩＭ上に投影される。マスクＭＳと被処理体ＩＭとは、光学的に共役の関係に配置される。露光装置２００は、スキャン露光方式の露光装置であるため、反射屈折型拡大投影光学系１００Ａに対し相対的にマスクＭＳと被処理体ＩＭを同期走査することによりマスクＭＳのパターンを被処理体ＩＭ上に拡大投影する。
【００５１】
マスクステージ２２０は、マスクＭＳを支持して図示しない移動機構に接続されている。マスクステージ２２０は、当業界周知のいかなる機構をも適用することができる。図示しない移動機構は、リニアモーターなどで構成され、制御部２４０に制御されながら少なくともＹ方向にマスクステージ２２０を駆動することでマスクＭＳを移動することができる。露光装置２００は、マスクＭＳと被処理体ＩＭを制御部２４０によって反射屈折型拡大投影光学系１００Ａに対して同期した状態で走査する。
【００５２】
反射屈折型投影光学系１００Ａは、マスクＭＳ面上のパターンを像面上に拡大投影する光学系である。反射屈折型投影光学系１００Ａは、上述した通りのいかなる形態をも適用可能であり、ここでの詳細な説明は省略する。なお、図３では、図２に示す反射屈折型拡大投影光学系１００Ａを使用するが、かかる形態は例示的であり本発明はこれに限定されない。
【００５３】
被処理体ＩＭは、本実施形態では、ガラス基板（液晶基板）であるが、ウェハその他の被処理体を広く含む。被処理体ＩＭには、フォトレジストが塗布されている。フォトレジスト塗布工程は、前処理と、密着性向上剤塗布処理と、フォトレジスト塗布処理と、プリベーク処理とを含む。前処理は、洗浄、乾燥などを含む。密着性向上剤塗布処理は、フォトレジストと下地との密着性を高めるための表面改質（即ち、界面活性剤塗布による疎水性化）処理であり、ＨＭＤＳ（Ｈｅｘａｍｅｔｈｙｌ−ｄｉｓｉｌａｚａｎｅ）などの有機膜をコート又は蒸気処理する。プリベークは、ベーキング（焼成）工程であるが現像後のそれよりもソフトであり、溶剤を除去する。
【００５４】
ステージ２３０は、被処理体ＩＭを支持する。ステージ２３０は、例えば、リニアモーターを利用してＸＹＺ方向に被処理体ＩＭを移動させる。マスクＭＳと被処理体ＩＭは、制御部２４０により制御され同期して走査される。また、マスクステージ２２０とステージ２３０の位置は、例えば、レーザー干渉計などにより監視され、両者は一定の速度比率で駆動される。ステージ２３０は、例えば、ダンパを介して床等の上に支持されるステージ定盤上に設けられ、マスクステージ２３０及び反射屈折型拡大投影光学系１００Ａは、例えば、床等の載置されたベースフレーム上にダンパ等を介して支持される図示しない鏡筒定盤上に設けられる。
【００５５】
制御部２４０は、図示しないＣＰＵ、メモリを有し、露光装置２００の動作を制御する。制御部２４０は、照明装置２１０、マスクステージ２２０（即ち、マスクステージ２２０の図示しない移動機構）、ステージ２３０（即ち、ステージ２３０の図示しない移動機構）と電気的に接続されている。ＣＰＵは、ＭＰＵなど名前の如何を問わずいかなるプロセッサも含み、各部の動作を制御する。メモリは、ＲＯＭ及びＲＡＭより構成され、露光装置２００を動作させるファームウェアを格納する。
【００５６】
露光において、光源部２１２から射出された光束は、照明光学系２１４によりマスクＭＳを、例えば、ケーラー照明する。マスクＭＳを通過してマスクパターンを反映する光は反射屈折型拡大投影光学系１００Ａにより被処理体ＩＭ上に結像する。本実施形態において、マスクＭＳと被処理体ＩＭを拡大倍率比の速度比で走査することにより、マスクＭＳの全面を露光する。なお、露光装置２００は、一括露光も可能であり、従来のマルチレンズ方式のようにパターンのつなぎ目がなく、トータルとして結像性能に優れている。
【００５７】
次に、図４及び図５を参照して、露光装置２００を利用したデバイス製造方法の実施例を説明する。図４は、デバイス（液晶ディスプレイ（ＬＣＤ）、ＣＣＤ、ＩＣやＬＳＩなどの半導体チップ等）の製造を説明するためのフローチャートである。ここでは、ＬＣＤの製造を例に説明する。ステップ１（アレイ設計）では、ＬＣＤのアレイ設計を行う。ステップ２（マスク製作）では、設計したアレイパターンを形成したマスクを製作する。ステップ３（基板製造）では、ガラスなどの材料を用いてガラス基板を製造する。ステップ４（アレイ製造）では、マスクとガラス基板を用いてリソグラフィー技術によってガラス基板上に実際のアレイを形成する。ステップ５（パネル製造）では、ステップ４によって作成されたガラス基板と、カラーフィルターとを整合して液晶パネル化する工程であり、配向処理工程（ラビング、ラビング後洗浄）、貼り合せ工程（アライメント、パネルギャップ制御、シール本硬化）、分断工程、液晶注入工程（液晶注入、封止、洗浄、過熱徐冷）等の工程を含む。ステップ６（モジュール製造）では、ＴＣＰ（Ｔａｐｅ Ｃａｒｒｉｅｒ Ｐａｃｋａｇｅ）方式やＣＯＧ（Ｃｈｉｐ Ｏｎ Ｇｌａｓｓ）方式を用いてステップ５で作成された液晶パネルを液晶チップ化する工程である。ステップ７（検査）では、ステップ６で作成された液晶ディスプレイの動作確認テスト、耐久性テストなどの検査を行う。こうした工程を経て液晶ディスプレイが完成し、それが出荷（ステップ８）される。
【００５８】
図５は、ステップ４のアレイ製造の詳細なフローチャートである。ステップ１１（薄膜形成）では、ガラス基板上に薄膜をＣＶＤ法などによって形成する。ステップ１２（酸化）では、ガラス基板の表面を酸化させる。ステップ１３（ドーピング）では、ガラス基板にドーピングを施す。ステップ１４（アニール）では、ガラス基板のアニールを行う。ステップ１５（レジスト処理）では、ガラス基板に感光剤を塗布する。ステップ１６（露光）では、露光装置２００によってマスクのパターンをガラス基板に露光する。ステップ１７（現像）では、露光したガラス基板を現像する。ステップ１８（エッチング）では、現像したレジスト像以外の部分を削り取る。ステップ１９（レジスト剥離）では、エッチングが済んで不要となったレジストを取り除く。本実施例のデバイス製造方法によれば、従来よりも高品位の液晶ディスプレイをスループットよく製造することができる。このように、露光装置２００を使用するデバイス製造方法、並びに結果物としてのデバイスも本発明の一側面を構成する。なお、これらのステップを繰り返し行うことによってデバイスを製造してもよいことは言うまでもない。
【００５９】
以上、本発明の好ましい実施例について説明したが、本発明はこれらの実施例に限定されないことはいうまでもなく、その要旨の範囲内で種々の変形及び変更が可能である。例えば、本実施形態の反射屈折型拡大投影光学系は、第１のレンズ群Ｇ１、負レンズ群ＧＮ、正レンズ群ＧＰ、第２のレンズ群Ｇ２において、さらにレンズ枚数を多くして収差補正の自由度を増加させても良い。また、本発明は、大画面をスキャン露光する露光装置にもスキャンしない露光をする露光装置にも適用可能である。なお、光学系全体を比例倍縮小（例えば、１／２倍）することによりレンズ径や全長を小さくして、一つのガラス基板上を２回走査するなどしてガラス基板全体を露光するようにしても良い。
【００６０】
本出願は、更に以下の事項を開示する。
【００６１】
〔実施態様１〕 物体面上のパターンを像面上に拡大して投影する拡大投影光学系とし、
前記物体面側から光路順に、少なくとも１枚の正レンズからなる第１のレンズ群と、前記第１のレンズ群により形成される瞳のほぼ共役点に配置された第１のミラーと、前記第１のミラーから距離を隔てて前記物体面側に配置され、前記第１のミラーからの光線を前記像面側へ反射させる第２のミラーと、前記第２のミラーよりも前記像面側へ配置され、前記第２のミラーからの光線を前記像面上に結像させ、少なくとも１枚の正レンズからなる第２のレンズ群とを有し、
前記投影に寄与する有効像面領域は、光軸中心を含まない軸外の円弧状の領域であることを特徴とする拡大投影光学系。
【００６２】
〔実施態様２〕 前記第２のミラーは、前記第１のレンズ群よりも前記像面側に配置されることを特徴とする実施態様１記載の拡大投影光学系。
【００６３】
〔実施態様３〕 前記第２のレンズ群は、前記第１のミラーよりも前記像面側に配置されることを特徴とする実施態様１記載の拡大投影光学系。
【００６４】
〔実施態様４〕 前記第１のミラーは、凹面ミラーであることを特徴とする実施態様１記載の拡大投影光学系。
【００６５】
〔実施態様５〕 前記第１のミラーの前記物体側近傍に、少なくとも１枚の負レンズを有する負レンズ群を配置したことを特徴とする実施態様１記載の拡大投影光学系。
【００６６】
〔実施態様６〕 前記第２のミラーの前記像面側近傍に、少なくとも１枚の正レンズを有する正レンズ群を配置したことを特徴とする実施態様１記載の拡大投影光学系。
【００６７】
〔実施態様７〕 前記第２のミラーは、凸面ミラーであることを特徴とする実施態様１記載の拡大投影光学系。
【００６８】
〔実施態様８〕 前記像面側は、テレセントリックであることを特徴とする実施態様１記載の拡大投影光学系。
【００６９】
〔実施態様９〕 前記物体面側は、テレセントリックであることを特徴とする実施態様１記載の拡大投影光学系。
【００７０】
〔実施態様１０〕 前記像側の開口数をＮＡとしたとき、
０．０５ ＜ ＮＡ ＜０．１５
を満足することを特徴とする実施態様１記載の拡大投影光学系。
【００７１】
〔実施態様１１〕 前記拡大投影光学系の倍率をβとしたとき、
−３．０ ＜ β ＜ −１．５
を満足することを特徴とする実施態様１記載の拡大投影光学系。
【００７２】
〔実施態様１２〕 前記第１のミラー、前記第２のミラーのうち、少なくとも１つが球面ミラーであることを特徴とする実施態様１記載の拡大投影光学系。
【００７３】
〔実施態様１３〕 前記第１のミラー、前記第２のミラーのうち、少なくとも１つが非球面ミラーであることを特徴とする実施態様１記載の拡大投影光学系。
【００７４】
〔実施態様１４〕 前記拡大投影光学系を構成するレンズは、少なくとも１つの非球面レンズを含むことを特徴とする実施態様１記載の拡大投影光学系。
【００７５】
〔実施態様１５〕 前記拡大投影光学系を構成するレンズは、少なくとも２種類の硝材からなることを特徴とする拡大投影光学系。
【００７６】
〔実施態様１６〕 実施態様１乃至１５のうちいずれか一項記載の拡大投影光学系と、
前記物体面上にマスクのパターンを位置付けるべく当該マスクを保持するステージと、
前記像面上に感光層を位置付けるべく基板を保持するステージと、
前記投影光学系の視野に対応する光により前記マスクを照明する照明装置と、
前記光で前記マスクを照明する状態で前記各ステージを同期して走査する手段とを有することを特徴とする露光装置。
【００７７】
〔実施態様１７〕 光源からの光で前記パターンを照明する照明光学系と、前記パターンからの光を前記像面上に投影する、実施態様１乃至１５のいずれか一項記載の投影光学系とを有することを特徴とする露光装置。
【００７８】
〔実施態様１８〕 前記投影光学系は、前記パターンからの反射光を前記像面上に投影することを特徴とする実施態様１７記載の露光装置。
【００７９】
〔実施態様１９〕 実施態様１６乃至１８のうちいずれか一項記載記載の露光装置を用いて被処理体を露光するステップと、
露光された前記被処理体に所定のプロセスを行うステップとを有することを特徴とするデバイス製造方法。
【００８０】
ここで、上述の実施態様１において、「ほぼ共役点」とは、「共役点に完全に一致した状態」又は「共役点に完全に一致させようとして誤差を含んだ状態」を含むものとするが、共役点から１００ｍｍの範囲内であればずれても構わない。但し、ここでの１００ｍｍとは、光学系全長（本実施例においては２２６８ｍｍ）の約５％という意味であり、全長が変われば１００ｍｍという数字も変わる。
【００８１】
また、実施態様５における、第１のミラーの物体側近傍とに、少なくとも１枚の負レンズを有する負レンズ群を配置したという記載の「近傍」とは、第１のミラーから光学系全長の約７％という意味であり、第１のミラーから約１５０ｍｍ以内に負レンズ群を配置するのが好ましい。また、実施態様６は実施態様５と同様であり、第２のミラーから光学系全長の約７％の範囲内、すなわち第２のミラーから約１５０ｍｍ以内に正レンズ群を配置するのが好ましい。
【００８２】
【発明の効果】
本発明の拡大投影光学系によれば、簡易な構成でありながらディスプレイの大画面化に対応し、スループットの低下及びマスク製造のコストアップを防止すると共に優れた結像性能を達成することができる。
【図面の簡単な説明】
【図１】本発明の拡大投影光学系を示す基本概念図である。
【図２】本発明の一側面としての拡大投影光学系１００Ａの例示的一形態及びその光路を示す概略断面図である。
【図３】図２に示す拡大投影光学系を有する露光装置を示す概略構成図である。
【図４】デバイス（液晶ディスプレイ（ＬＣＤ）、ＣＣＤ、ＩＣやＬＳＩなどの半導体チップ等）の製造を説明するためのフローチャートである。
【図５】図４に示すステップ４のアレイ製造の詳細なフローチャートである。
【符号の説明】
１００、１００Ａ 反射屈折型拡大投影光学系
ＭＳ マスク（物体面）
ＩＭ ガラス基板（像面）
Ｍ１ 第１のミラー
Ｍ２ 第２のミラー
Ｇ１ 第１のレンズ群
Ｇ２ 第２のレンズ群
ＧＰ 正レンズ群
ＧＮ 負レンズ群
Ｍ１ 第１のミラー
Ｍ２ 第２のミラー
２００ 露光装置
２１０ 照明装置
２２０ マスクステージ
２３０ ステージ
２４０ 制御部[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention generally relates to a projection optical system, and more particularly, to a catadioptric magnifying projection optical system for projecting and exposing an object to be processed, such as a glass substrate for a liquid crystal display (LCD: Liquid Crystal Display). The present invention is suitable, for example, when manufacturing a large-screen liquid crystal display.
[0002]
[Prior art]
2. Description of the Related Art In recent years, liquid crystal displays (hereinafter, referred to as LCDs) have been widely used as display elements of televisions, personal computers, and the like. LCDs are manufactured by patterning transparent thin-film electrodes on a glass substrate using a photolithography (baking) technique. An exposure apparatus for manufacturing LCDs (liquid crystal display manufacturing apparatus) has an equal-magnification optical system composed of mirrors, and an object plane (mask plane) and an image plane (glass substrate) for a slit-shaped area whose aberration has been corrected. To form an image.
[0003]
As this type of optical system, for example, an optical system having a very simple configuration in which a mask pattern is basically imaged at the same magnification with two mirrors, convex and concave, has been proposed (for example, Patent Document 1). reference). The effective area that contributes to the projection of the mask pattern is an area on an arc having the same image height outside the optical axis.
[0004]
Also, a multi-lens optical system in which a plurality of optical systems of the same size are arranged has been proposed, and an exposure area is secured by configuring such a multi-lens optical system (for example, see Patent Document 2). .
[0005]
[Patent Document 1]
JP-A-52-005544
[Patent Document 2]
JP-A-07-057986
[0006]
[Problems to be solved by the invention]
However, in the optical system proposed in Patent Literature 1, the image plane width that can satisfactorily correct the field curvature and astigmatism is small because of the simple configuration. Therefore, the arc-shaped slit width when illuminating the mask is used. (The length in the scanning direction) cannot be secured large. Therefore, the exposure illuminance could not be increased, and it was difficult to improve the throughput.
[0007]
On the other hand, in the optical system proposed in Patent Document 2, since the multi-lens system is used, it is necessary to make the optical performance and the mechanical performance of each optical system used to the same degree, and it is difficult to adjust them. Was. Further, the images formed by the adjacent optical systems need to be overlapped so that the joints are double-exposed, and the continuity of the same amount of exposure and the same optical performance is required. Was very difficult to prepare and adjust.
[0008]
Further, a problem in responding to the recent increase in the screen size of the display is the cost of manufacturing a mask. The two optical systems described above both project a mask pattern at the same magnification, and require a mask of the same size as the screen becomes larger. Therefore, there is a problem that the mask becomes larger and costs increase. there were.
[0009]
Therefore, the present invention provides a catadioptric magnifying projection optical system which has a simple configuration, can cope with an increase in the screen size of a display, prevents a decrease in throughput and an increase in mask manufacturing cost, and has excellent imaging performance. For illustrative purposes.
[0010]
[Means for Solving the Problems]
In order to achieve the above object, an enlarged projection optical system according to one aspect of the present invention is a catadioptric enlarged projection optical system that enlarges and projects a pattern on an object plane onto an image plane. A first lens group having at least one positive lens, a first mirror disposed at a substantially conjugate point of a pupil formed by the first lens group, and the first mirror in order of optical path from the side A second mirror arranged at a distance from the object plane side to reflect light rays from the first mirror toward the image plane side, and a second mirror arranged closer to the image plane side than the second mirror; A second lens group having at least one positive lens for forming a light beam from the second mirror on the image plane; and an effective image plane area contributing to the projection is located at an optical axis center. Is an off-axis arc-shaped region that does not include.
[0011]
Further objects and other features of the present invention will become apparent from preferred embodiments described below with reference to the accompanying drawings.
[0012]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, a catadioptric magnifying projection optical system 100 and an exposure apparatus 200 according to one aspect of the present invention will be described with reference to the accompanying drawings. However, the present invention is not limited to these embodiments, and each component may be replaced as long as the object of the present invention is achieved. In each of the drawings, the same members are denoted by the same reference numerals, and redundant description will be omitted. Here, FIG. 1 is a basic conceptual diagram showing an enlarged projection optical system 100 of the present invention. FIG. 2 is a schematic cross-sectional view showing an exemplary embodiment of an enlarged projection optical system 100A according to one aspect of the present invention and an optical path thereof.
[0013]
Referring to FIG. 1, an enlarged projection optical system 100 (hereinafter simply referred to as a projection optical system 100) of the present invention converts a pattern on an object plane MS (for example, a mask plane) to an image plane IM (for example, a substrate or the like). This is a catadioptric magnifying projection optical system that magnifies and projects onto the object surface to be processed. The projection optical system 100 of the present invention includes, as light sources, g-line (wavelength: about 436 nm), h-line (wavelength: about 405 nm), i-line (wavelength: about 365 nm), KrF excimer laser (wavelength: about 248 nm), ArF excimer laser (wavelength: About 193 nm), F ₂ It is an optical system suitable for a laser (wavelength: about 157 nm) and the like.
[0014]
The projection optical system 100 is basically a one-time imaging optical system, and includes a first positive lens group G1, a first mirror M1 (concave mirror), and a second mirror in the optical path order from the object plane MS side. M2 and a positive second lens group G2. In the projection optical system 100, a first mirror M1 is disposed near a pupil conjugate point formed by refracting a light beam from the object plane MS by the first lens group G1. The second mirror M2 is reflected toward the image plane IM, and the reflected light passes outside the effective diameter of the first mirror M1 and is projected onto the image plane IM by the second lens group G2. It should be noted at this time that the optical system as a whole has a magnification.
[0015]
In such a configuration, the projection optical system 100 of the present invention has an advantage that it is preferable in reducing the cost of manufacturing a mask when the screen of the liquid crystal display is enlarged. In other words, the problem of the prior art has been solved in that the enlargement magnification allows the mask to be reduced in size with respect to the enlargement of the screen of the liquid crystal display, thereby reducing the manufacturing cost.
[0016]
Note that the first mirror M1 is arranged near the pupil conjugate point, but may be, for example, within a range of ± 100 mm. If it exceeds this, distortion, coma and the like generated in the first mirror M1 increase, which is not preferable.
[0017]
The projection optical system 100 is basically arranged so as to form a coaxial system, and is a coaxial optical system axially symmetric about one optical axis. However, in terms of aberration correction or aberration adjustment, the first lens group G1, the first mirror M1, the second mirror M2, and the second lens group G2 of the projection optical system 100 are completely coaxial. It is not necessary to dispose them, and a slight eccentricity may be used to improve aberration.
[0018]
In addition, by using a concave mirror having a positive power as the first mirror M1 that bears the main power of the projection optical system 100, the generation of the axial chromatic aberration is suppressed, and the negative mirror is placed near the object plane MS side of the first mirror M1. By disposing the lens group GN, it is possible to further correct axial chromatic aberration. At this time, in order to effectively correct the axial chromatic aberration, the negative lens group GN and the first mirror M1 are preferably brought into close contact with each other, and are preferably arranged within 150 mm. In addition, the positive lens group GP is arranged near the image plane IM side of the second mirror M2, and the Petzval sum of the optical system is optimally corrected by adjusting the power relationship between the second mirror M2 and the positive lens group GP. It is also possible. At this time, in order to effectively correct the Petzval sum, the second mirror M2 and the positive lens group GP are preferably brought into close contact with each other, and are preferably arranged within 150 mm.
[0019]
The second mirror M2 may be either a convex mirror or a concave mirror, but is preferably a convex mirror in terms of the configuration of the optical system. Thus, the Petzval sum can be set in the positive direction together with the positive lens group GP, so that the negative Petzval sum generated in the first mirror M1 and the negative lens group GN that bears the main power can be canceled. Therefore, it is possible to secure a large image plane IM width after aberration correction, and it is possible to increase the width of the arc-shaped slit formed by the illumination system. As a result, it is possible to improve the throughput of the exposure apparatus. It solves the conventional problem in that it can do so.
[0020]
Further, since the shape of the positive lens group GP is a semicircular shape only in the negative direction from the optical axis in FIG. 1, the processing and holding structure thereof is complicated. However, a circular shape (not shown) like a normal lens is used. ) To simplify the processing and holding structure. In this case, the light beam passes through the positive lens group GP three times, but the portion in the positive direction from the optical axis is included in the first lens group G1.
[0021]
Further, since the second mirror M2 is positioned closer to the image plane IM than the first lens group G1, the degree of freedom of the power and the shape of the lenses constituting the first lens group G1 is increased. This is preferable in terms of correction of distortion and the like.
[0022]
In addition, since the second lens group G2 is positioned closer to the image plane IM than the first mirror M1, the power and shape of the lenses constituting the second lens group G2 are increased, and the degree of telecentricity is increased. This is preferable in terms of correction of distortion and the like.
[0023]
Furthermore, in the projection optical system 100 of the present invention, the emitted light on the object plane MS side is telecentric, and the change in magnification is small even if the object plane MS moves in the optical axis direction.
[0024]
Further, the emitted light on the image plane IM side is also telecentric, and the change in magnification is small even when the image plane IM moves in the optical axis direction.
[0025]
Further, since the projection optical system 100 is arranged so as to form a coaxial system, it has an advantage that aberration is corrected in a ring-shaped image plane IM centered on the optical axis, which is preferable.
[0026]
When the numerical aperture on the image plane IM side is NA, the projection optical system 100 of the present invention preferably satisfies the following conditional expression (1).
[0027]
(Equation 1)

[0028]
Equation 1 defines the numerical aperture NA on the image plane IM side to which the present invention is applied, and is preferably in this range mainly for a liquid crystal display. If the lower limit is exceeded, the resolving power will be insufficient. If the upper limit is exceeded, the light beam width will be large, which is not good because the lens diameter will increase.
[0029]
When the magnification is β, the projection optical system 100 of the present invention preferably satisfies the following conditional expression (2).
[0030]
(Equation 2)

[0031]
Equation 2 defines the magnification β of the optical system to which the present invention is applied. If the lower limit is exceeded, the object height decreases, and at the same time, the numerical aperture NA on the object surface MS side increases and the luminous flux width also increases. Therefore, it is difficult to form an optical system without interfering a light beam with a mirror or a lens. If the upper limit is exceeded, the height of the object becomes high, so that the size of the mask becomes large and it becomes difficult to reduce the mask manufacturing cost.
[0032]
Incidentally, the mirror constituted by the present invention may be a spherical mirror or an aspherical mirror. Also, it is effective to correct the aberration by using an aspherical lens as the lens, and the number of lenses can be reduced. Further, as means for correcting chromatic aberration, two or more types of glass materials or an achromatic lens can be used. Preferably, when correcting lateral chromatic aberration, glass is selected such that the dispersion of the first lens group G1 having relatively positive refractive power is larger than the dispersion of the second lens group G2 having relatively positive refractive power. Good.
[0033]
Further, it is preferable to determine the mirror shape and the lens power so that the sum of Petzval terms becomes zero or near zero in the entire optical system.
[0034]
The shape of the aspherical mirror and lens used in the present invention is represented by a general aspherical expression shown in the following Expression 3.
[0035]
[Equation 3]

[0036]
In Equation 3, Z is the coordinate in the direction of the optical axis, c is the curvature (reciprocal of the radius of curvature r), h is the height from the optical axis, k is the cone coefficient, A, B, C, D, E, F, and G. , H, J,... Are the fourth-order, sixth-order, eighth-order, tenth-order, twelve-order, fourteenth, sixteenth, eighteenth, twenty-order,.
[0037]
In the present invention, an aperture stop (not shown) may be provided near the first mirror M1. The diameter of the aperture stop may be fixed or variable. In the case where the numerical aperture is variable, the numerical aperture of the optical system can be changed by changing the diameter of the aperture stop. By making the aperture stop variable, advantages such as obtaining a large depth of focus can be obtained, whereby the image can be further stabilized.
[0038]
Here, the result of an illumination experiment using the catadioptric magnifying projection optical system 100A of the present invention shown in FIG. 2 will be described. In FIG. 2, MS indicates a mask placed at the object plane position, and IM indicates a glass substrate placed at the image plane position.
[0039]
In the catadioptric magnifying projection optical system 100A, the mask MS is illuminated by an illumination system (not shown) that emits light having a wavelength of about 365.0 nm, and the transmitted light from the mask MS passes through the first lens group G1 to reduce the distance. The mask pattern is enlarged on the glass substrate IM that passes through the positive lens group GP, the second mirror M2 (convex mirror), and the positive lens group GP, and is finally placed at the image plane position by the second lens group G2. Forming an image. In the present embodiment, the positive lens group GP also serves as a part of the first lens group G1, and the light beam passes three times.
[0040]
In the catadioptric magnifying projection optical system 100A shown in FIG. 2, it is an arc-shaped image plane having a NA of 0.08, a magnification of 2.times., An object height of 150 mm to 300 mm, and an image height of 300 mm to 600 mm and a width of 300 mm. Here, Table 1 shows numerical values (radius of curvature, surface interval, refractive index) of the catadioptric magnifying projection optical system 100A of FIG. 2, and Table 2 shows aspheric coefficients.
[0041]
[Table 1]

[0042]
[Table 2]

[0043]
The aberrations (calculated at several points of the image height) that do not include the manufacturing error of the catadioptric expansion projection optical system 100A shown in FIG. 2 are wavefront aberration = 0.032λrms and distortion maximum = 67 nm, which is a wavelength of 365 nm. This is a diffraction limited (diffraction limited) optical system, and has sufficient performance even when the target resolution is 3 μm. The total length of the optical system is 2266 mm, and the maximum effective diameter is 1349 mm in the second lens group G2.
[0044]
As described above, the catadioptric magnifying projection optical system 100A of the present invention is an optical system that achieves diffraction-limited performance with a very simple configuration and has a large aberration-corrected image plane width.
[0045]
Hereinafter, an exposure apparatus 200 to which the catadioptric magnifying projection optical system 100A of the present invention is applied will be described with reference to FIG. FIG. 3 is a schematic configuration diagram showing an exposure apparatus 200 having the catadioptric magnifying projection optical system 100A. Referring to FIG. 3, exposure apparatus 200 includes illumination device 210, mask MS, mask stage 220, catadioptric magnifying projection optical system 100 </ b> A, object to be processed IM, stage 230, and control unit 240. Having.
[0046]
The exposure apparatus 200 of the present invention is, for example, a projection exposure apparatus that exposes a pattern formed on a mask MS to a processing object IM by a scan exposure method. Such an exposure apparatus is suitable for manufacturing, for example, a large-screen liquid crystal display corresponding to 40 inches. Here, the “scan exposure method” is an exposure method that exposes the entire mask pattern by synchronously scanning a part of the pattern on the mask with the mask and the substrate.
[0047]
The illumination device 210 illuminates the mask MS on which the transfer pattern is formed, and includes a light source 212 and an illumination optical system 214.
[0048]
The light source unit 212 uses, for example, a laser as a light source. The laser is an ArF excimer laser having a wavelength of about 193 nm, a KrF excimer laser having a wavelength of about 248 nm, and a Fr excimer laser having a wavelength of about 153 nm. ₂ Although a laser or the like can be used, the type of laser is not limited. For example, a YAG laser may be used, and the number of lasers is not limited. For example, if two solid-state lasers operating independently are used, there is no mutual coherence between the solid-state lasers, and speckle due to coherence is considerably reduced. In order to further reduce speckle, the optical system may be swung linearly or rotationally. When a laser is used for the light source unit 212, a light beam shaping optical system for shaping a parallel light beam from the laser light source into a desired beam shape and an incoherent optical system for making a coherent laser light beam incoherent are used. Is preferred. The light source that can be used for the light source unit 212 is not limited to a laser, and one or more lamps such as a mercury lamp and a xenon lamp can be used.
[0049]
The illumination optical system 214 is an optical system that illuminates the mask MS, and includes a lens, a mirror, a light integrator, a stop, and the like. For example, a condenser lens, a fly-eye lens, an aperture stop, a condenser lens, a slit, and an imaging optical system are arranged in this order. The illumination optical system 214 can be used regardless of on-axis light or off-axis light. The light integrator includes a fly-eye lens, an integrator formed by stacking two sets of cylindrical lens array (or lenticular lenses) plates, and the like, but may be replaced with an optical rod or a diffraction element.
[0050]
The mask MS is a reflective or transmissive mask on which a pattern (or image) to be transferred is formed, and is supported and driven by the mask stage 220. The mask MS can be reduced in size by the catadioptric magnifying projection optical system 100A as compared with the related art. The diffracted light emitted from the mask MS passes through the catadioptric magnifying projection optical system 100A and is projected onto the processing object IM. The mask MS and the processing object IM are arranged in an optically conjugate relationship. Since the exposure apparatus 200 is a scan exposure type exposure apparatus, the mask MS and the object IM are synchronously scanned with respect to the catadioptric magnifying projection optical system 100A so that the pattern of the mask MS is subjected to the object IM. Enlarge and project upward.
[0051]
The mask stage 220 supports the mask MS and is connected to a moving mechanism (not shown). As the mask stage 220, any mechanism known in the art can be applied. The moving mechanism (not shown) is configured by a linear motor or the like, and can move the mask MS by driving the mask stage 220 at least in the Y direction while being controlled by the control unit 240. The exposure apparatus 200 scans the mask MS and the object IM in synchronization with the catadioptric magnifying projection optical system 100A by the control unit 240.
[0052]
The catadioptric projection optical system 100A is an optical system that enlarges and projects a pattern on a mask MS surface onto an image plane. The catadioptric projection optical system 100A can apply any of the forms described above, and a detailed description thereof will be omitted. In FIG. 3, the catadioptric magnifying projection optical system 100A shown in FIG. 2 is used, but such an embodiment is exemplary and the present invention is not limited to this.
[0053]
In the present embodiment, the object to be processed IM is a glass substrate (liquid crystal substrate), but includes a wide range of wafers and other objects to be processed. A photoresist is applied to the object IM. The photoresist application step includes a pretreatment, an adhesion improver application process, a photoresist application process, and a pre-bake process. The pretreatment includes washing, drying, and the like. The adhesion improver application treatment is a surface modification (that is, hydrophobicity treatment by applying a surfactant) treatment for improving the adhesion between the photoresist and the base, and is used to remove an organic film such as HMDS (Hexamethyl-disilazane). Coat or steam. Prebaking is a baking (firing) step, but is softer than that after development, and removes the solvent.
[0054]
The stage 230 supports the object to be processed IM. The stage 230 moves the object IM in the XYZ directions using, for example, a linear motor. The mask MS and the object IM are controlled by the control unit 240 and scanned synchronously. The positions of the mask stage 220 and the stage 230 are monitored by, for example, a laser interferometer or the like, and both are driven at a constant speed ratio. The stage 230 is provided, for example, on a stage base supported on a floor or the like via a damper. The mask stage 230 and the catadioptric magnifying projection optical system 100A are, for example, a base mounted on a floor or the like. It is provided on a lens barrel base (not shown) supported on a frame via a damper or the like.
[0055]
The control unit 240 has a CPU and a memory (not shown) and controls the operation of the exposure apparatus 200. The control unit 240 is electrically connected to the illumination device 210, the mask stage 220 (ie, a moving mechanism (not shown) of the mask stage 220), and the stage 230 (ie, a moving mechanism (not shown) of the stage 230). The CPU includes any processor, such as an MPU, regardless of its name, and controls the operation of each unit. The memory includes a ROM and a RAM, and stores firmware for operating the exposure apparatus 200.
[0056]
In the exposure, the light beam emitted from the light source unit 212 illuminates the mask MS with, for example, Koehler illumination by the illumination optical system 214. Light that passes through the mask MS and reflects the mask pattern is imaged on the processing object IM by the catadioptric magnifying projection optical system 100A. In the present embodiment, the entire surface of the mask MS is exposed by scanning the mask MS and the object to be processed IM at a speed ratio of the magnification ratio. The exposure apparatus 200 is also capable of batch exposure, has no seams of patterns unlike the conventional multi-lens system, and has excellent imaging performance as a whole.
[0057]
Next, an embodiment of a device manufacturing method using the exposure apparatus 200 will be described with reference to FIGS. FIG. 4 is a flowchart for explaining the manufacture of a device (liquid crystal display (LCD), CCD, semiconductor chip such as IC or LSI, etc.). Here, the manufacture of LCD will be described as an example. In step 1 (array design), an LCD array is designed. Step 2 (mask fabrication) forms a mask on which the designed array pattern is formed. In step 3 (substrate manufacture), a glass substrate is manufactured using a material such as glass. Step 4 (array manufacture) forms an actual array on the glass substrate by lithography using the mask and the glass substrate. Step 5 (panel manufacturing) is a step of aligning the glass substrate formed in step 4 with the color filter to form a liquid crystal panel. The alignment step (rubbing, cleaning after rubbing) and the bonding step (alignment, It includes steps such as panel gap control, seal main curing), cutting step, and liquid crystal injecting step (liquid crystal injecting, sealing, washing, overheating and slow cooling). Step 6 (module manufacture) is a process of forming the liquid crystal panel formed in step 5 into a liquid crystal chip using a TCP (Tape Carrier Package) method or a COG (Chip On Glass) method. In step 7 (inspection), inspections such as an operation check test and a durability test of the liquid crystal display created in step 6 are performed. Through these steps, a liquid crystal display is completed and shipped (step 8).
[0058]
FIG. 5 is a detailed flowchart of the array manufacturing in Step 4. Step 11 (formation of a thin film) forms a thin film on the glass substrate by a CVD method or the like. Step 12 (oxidation) oxidizes the surface of the glass substrate. Step 13 (doping) is to dope the glass substrate. Step 14 (annealing) anneals the glass substrate. In step 15 (resist processing), a photosensitive agent is applied to the glass substrate. Step 16 (exposure) uses the exposure apparatus 200 to expose a mask pattern onto the glass substrate. Step 17 (development) develops the exposed glass substrate. Step 18 (etching) removes portions other than the developed resist image. Step 19 (resist stripping) removes unnecessary resist after etching. According to the device manufacturing method of the present embodiment, it is possible to manufacture a liquid crystal display with higher quality than before in a high throughput. As described above, the device manufacturing method using the exposure apparatus 200 and the resulting device also constitute one aspect of the present invention. It goes without saying that the device may be manufactured by repeating these steps.
[0059]
The preferred embodiments of the present invention have been described above. However, it goes without saying that the present invention is not limited to these embodiments, and various modifications and changes can be made within the scope of the invention. For example, the catadioptric magnifying projection optical system of the present embodiment increases the number of lenses in the first lens group G1, the negative lens group GN, the positive lens group GP, and the second lens group G2 to correct aberration. The degree of freedom may be increased. Further, the present invention is applicable to an exposure apparatus that performs scanning exposure on a large screen and an exposure apparatus that performs exposure without scanning. The entire optical system is exposed by reducing the lens diameter and overall length by reducing the entire optical system by a factor of 2 (for example, 1/2 times), and scanning one glass substrate twice. May be.
[0060]
The present application further discloses the following matters.
[0061]
Embodiment 1 An enlarged projection optical system for enlarging and projecting a pattern on an object plane onto an image plane,
A first lens group consisting of at least one positive lens in the order of the optical path from the object plane side; a first mirror arranged at a substantially conjugate point of a pupil formed by the first lens group; A second mirror disposed on the object plane side at a distance from the first mirror and reflecting light rays from the first mirror to the image plane side; and a second mirror closer to the image plane side than the second mirror. And a second lens group comprising at least one positive lens, wherein the second lens group is arranged to form a light beam from the second mirror on the image plane.
An enlarged projection optical system, wherein the effective image plane area contributing to the projection is an off-axis arc-shaped area that does not include the center of the optical axis.
[0062]
[Second Embodiment] The enlarged projection optical system according to the first embodiment, wherein the second mirror is disposed closer to the image plane than the first lens group.
[0063]
[Embodiment 3] The enlarged projection optical system according to Embodiment 1, wherein the second lens group is disposed closer to the image plane than the first mirror.
[0064]
[Embodiment 4] The enlarged projection optical system according to Embodiment 1, wherein the first mirror is a concave mirror.
[0065]
[Embodiment 5] The enlarged projection optical system according to Embodiment 1, wherein a negative lens group having at least one negative lens is arranged near the object side of the first mirror.
[0066]
[Sixth Embodiment] An enlarged projection optical system according to the first embodiment, wherein a positive lens group having at least one positive lens is arranged near the image plane side of the second mirror.
[0067]
Seventh Embodiment An enlarged projection optical system according to the first embodiment, wherein the second mirror is a convex mirror.
[0068]
[Eighth Embodiment] The enlarged projection optical system according to the first embodiment, wherein the image plane side is telecentric.
[0069]
[Embodiment 9] The enlarged projection optical system according to Embodiment 1, wherein the object plane side is telecentric.
[0070]
[Embodiment 10] When the numerical aperture on the image side is NA,
0.05 <NA <0.15
The magnifying projection optical system according to the first embodiment, characterized by satisfying the following.
[0071]
[Embodiment 11] When the magnification of the enlarged projection optical system is β,
−3.0 <β <−1.5
The magnifying projection optical system according to the first embodiment, characterized by satisfying the following.
[0072]
[Embodiment 12] The enlarged projection optical system according to Embodiment 1, wherein at least one of the first mirror and the second mirror is a spherical mirror.
[0073]
[Thirteenth Embodiment] An enlarged projection optical system according to the first embodiment, wherein at least one of the first mirror and the second mirror is an aspherical mirror.
[0074]
[Embodiment 14] The magnifying projection optical system according to embodiment 1, wherein the lens constituting the magnifying projection optical system includes at least one aspherical lens.
[0075]
[Embodiment 15] The magnifying projection optical system, wherein a lens constituting the magnifying projection optical system is made of at least two kinds of glass materials.
[0076]
[Embodiment 16] The enlarged projection optical system according to any one of Embodiments 1 to 15,
A stage for holding the mask to position the pattern of the mask on the object plane,
A stage for holding a substrate to position a photosensitive layer on the image plane;
An illumination device that illuminates the mask with light corresponding to the field of view of the projection optical system,
Means for synchronously scanning each of the stages while illuminating the mask with the light.
[0077]
[Embodiment 17] The illumination optical system according to any one of Embodiments 1 to 15, wherein the illumination optical system illuminates the pattern with light from a light source, and the light from the pattern is projected on the image plane. An exposure apparatus comprising:
[0078]
Embodiment 18 The exposure apparatus according to embodiment 17, wherein the projection optical system projects reflected light from the pattern onto the image plane.
[0079]
[Embodiment 19] A step of exposing a workpiece using the exposure apparatus according to any one of Embodiments 16 to 18,
Performing a predetermined process on the exposed object to be processed.
[0080]
Here, in the above-described first embodiment, the “almost conjugate point” includes “a state that completely matches the conjugate point” or “a state that includes an error in order to completely match the conjugate point”, It may be shifted within a range of 100 mm from the conjugate point. However, 100 mm here means about 5% of the entire length of the optical system (2268 mm in this embodiment), and if the total length changes, the figure of 100 mm also changes.
[0081]
In the fifth embodiment, “near” in which a negative lens group having at least one negative lens is arranged near the object side of the first mirror means “near the entire length of the optical system from the first mirror”. This means about 7%, and it is preferable to arrange the negative lens group within about 150 mm from the first mirror. The sixth embodiment is the same as the fifth embodiment, and it is preferable to dispose the positive lens group within a range of about 7% of the entire length of the optical system from the second mirror, that is, within about 150 mm from the second mirror.
[0082]
【The invention's effect】
ADVANTAGE OF THE INVENTION According to the expansion projection optical system of this invention, it can respond to enlargement of a display screen with a simple structure, can prevent the fall of a throughput and the cost increase of mask manufacture, and can achieve the outstanding imaging performance. .
[Brief description of the drawings]
FIG. 1 is a basic conceptual diagram showing an enlarged projection optical system according to the present invention.
FIG. 2 is a schematic cross-sectional view showing an exemplary embodiment of an enlarged projection optical system 100A as one aspect of the present invention and an optical path thereof.
FIG. 3 is a schematic configuration diagram showing an exposure apparatus having the enlarged projection optical system shown in FIG.
FIG. 4 is a flowchart for explaining the manufacture of a device (a liquid crystal display (LCD), a CCD, a semiconductor chip such as an IC or LSI, etc.).
FIG. 5 is a detailed flowchart of the array manufacture in step 4 shown in FIG. 4;
[Explanation of symbols]
100, 100A catadioptric magnifying projection optical system
MS mask (object surface)
IM glass substrate (image surface)
M1 First mirror
M2 Second mirror
G1 First lens group
G2 Second lens group
GP positive lens group
GN negative lens group
M1 First mirror
M2 Second mirror
200 Exposure equipment
210 Lighting device
220 mask stage
230 stages
240 control unit

Claims (1)

An enlarged projection optical system for enlarging and projecting a pattern on an object plane onto an image plane,
A first lens group having at least one positive lens in the order of the optical path from the object plane side; a first mirror arranged at a substantially conjugate point of a pupil formed by the first lens group; A second mirror disposed on the object plane side at a distance from the first mirror and reflecting light rays from the first mirror to the image plane side; and a second mirror closer to the image plane side than the second mirror. And a second lens group having at least one positive lens, wherein the second lens group is arranged to form a light beam from the second mirror on the image plane.
An enlarged projection optical system, wherein the effective image plane area contributing to the projection is an off-axis arc-shaped area that does not include the center of the optical axis.

Images