JP4256519B2 - Laser oscillation apparatus, exposure apparatus, and device manufacturing method - Google Patents

Description

【００５１】
で与えられる。（ξ：電波インピーダンス／δ：スキンデプス）この両者の内より支配的な損失が、例えばプラズマに供給されるエネルギより小さければよい。すなわち、プラズマでのマイクロ波の吸収率をｒとすると、プラズマがカットオフ状態の場合はｒ≪１であり、
スロット面とプラズマ界面との間を往復（多重反射）することを考慮すると、
ｅｘｐ（−２α・ｎλg ／２）＜ｒ ・・・（４）
を満たすｎを用いて、均一化線路の最大長を定義することができる。
【００５２】
しかしながら、マイクロ波の効率の点では吸収率ｒに対してより低い損失に設定することが重要でありｒに対し、１／１０〜１／１００程度少なくなるような設計が好ましい（このような設定をすることで、より損失の少ない系を設計できる。）。
【００５３】
ここで、誘電体１４を通路１１に充填した場合の具体的な実験例を以下にしめす。
ａ＝４２ｍｍ，ｂ＝２１ｍｍ、導波管共振器長（長手方向、即ちレーザ発振方向）２２０．８ｍｍのＥ面放出アンテナを用い、スロットの前面に金属壁１２を配した２．４５ＧＨｚのＡｌ合金筐体のマイクロ波照射アンテナを製作した。導波管共振器、即ち通路１１内には、誘電率９．８のアルミナが充填されている。このとき、導波管共振器内の管内波長は、４４．２ｍｍである。したがって、スロットピッチも４４．２ｍｍに設定してある。
【００５４】
スロットから放出されたマイクロ波は通路１１内に放出される。この通路１１は近似的には平行平板型の導波路であり、この近似のもとでは波長は自由空間での波長と等しく（但し、誘電体内部）３９．１ｍｍである。実際は、通路１１のレーザ発振方向の長さ２３５．３ｍｍをａとする方形導波管であるが、このときの管内波長は３９．２ｍｍであり、自由空間の波長に比べ３．５×１０^-3程度しか変わらないため、本構造では自由空間長の波長近似を用いることも可能である。このときの半波長は１９．６ｍｍであり、通路１１のスロット１０面から放出面までの距離は、ｎ：１，２，３…に対して１９．６ｍｍ，３９．２ｍｍ，５８．８ｍｍ…で与えられる。
【００５５】
ここで、共振器における損失を考慮する。誘電損によるαは、アルミナの抵抗卓が１０¹¹Ω・ｃｍのとき、５．２２×１０^-7ｄＢ／ｍであり、管壁吸収による損失は、アルミナの抵抗率を２．６５×１０^-6Ω・ｃｍとして、０．２３４ｄＢ／ｍである。この場合、支配的な損失は管壁の吸収であるため、これに着目する。１９．６ｍｍ進行する度に導波管を伝搬するエネルギーに対して０．００５３％の損失が発生する。従って、例えば通路１１を１往復する際の損失を投入エネルギーの０．０２％程度に押さえるために、ｎを４（損失：０．２１％）より小さく最も均一化の効果が得られる３に設定した。実際は、多重反射が起こるため、このように低い損失レベルに抑え込む必要がある。
【００５６】
（変形例３）
この変形例３では、図９（ａ），図９（ｂ）（図３（ａ），図３（ｂ）と同様の断面図）に示すように、通路１１の先端部位１３の近傍のみが幅広、具体的には、その半値幅αが、
α＝λg ／４
又は、
α＝λg ／２
となる幅広部１６を通路１１が有するように金属壁１２を形成する。
【００５７】
この場合、幅広部１６は通路１１に倣ってレーザ管２の長手方向に導波管１の全域にわたるように形成されており、幅広部１６が上記の如き幅に形成されていることから、この幅広部１６でマイクロ波の共振のエネルギーを効率良く集中させることが可能となる。
【００５８】
変形例２に挙げた構造を持つ導波路に対し、本構造を付加した導波路を製作した。このとき、αがλg ／４及びλg ／２に対しそれぞれ１９．６ｍｍ及び３９ｍｍであり、１６の高さを５ｍｍとして設計した。また、通路１１の厚みは４ｍｍとしている。このとき、１６に存在するエネルギーは、通路１１及び１６に存在するエネルギーのそれぞれ３１．３％／４７．７％であり、このことから窓部１５に近い部位（即ち１６）にエネルギーが集中されていることが分かる。この比較では、αがλg ／２である場合の方がよりエネルギーが集中しているように思えるが、１６の中心からλg ／４の距離内（即ちスロット１０近傍）に存在するマイクロ波のエネルギーに着目すると、通路１１及び１６に存在するエネルギーのそれぞれ３１．３％／２３．８％であり、αがλg ／４である場合の方がよりスロット１０近傍にエネルギーを集中させる効果が高いと言える。
【００５９】
更に、変形例３の他の形態を図１０に示す。この場合、幅広部１６の幅が、スロット１０から放出されるマイクロ波の強度分布を反映してレーザ管２の長手方向に沿って異なる値とされている。即ちここでは、金属壁１２を設けて通路１１を形成するに加えて、更なるマイクロ波の波面の均一化を図るため、通路１１のマイクロ波放出部位での均一化をより是正するように当該放出部位での不均一性に合わせて、幅広部１６の幅（又は半値幅α）を変化させた構造とする。
【００６０】
これにより、レーザ管２内のエキシマレーザガスには更に均一な平面波とされたマイクロ波が到達することになり、レーザ管２の長手方向にわたって均一なプラズマ放電が実現され、レーザ発光の更なる均一化に寄与する。
【００６１】
この効果は、空間的な間隙の形状を変化させることにより、伝播路の特性を変化できるというマイクロ波固有の性質によるものである。長さＬ特性インピーダンスＺ₀ である終端短絡導波路のインピーダンスＺは、
Ｚ＝ｊＺ₀ ｔａｎ（（２π／λg ）Ｌ）
となる。これは即ち如何なる値を持つ誘導性奏子（ディスクリートな素子でいうインダクタンス、コイル）及び容量性素子（ディスクリートな素子でいうキャパシタンス、キャパシタ）をＬを変化させるだけで形成することができることを示している。スロットライン方向に半値幅αを変化させるということは、電磁波にとってのスロットのインピーダンスを付随的に変化させることになり（等価回路的にみると、スロットに対して連続的にさまざまな値を持つコイルやキャパシタが並列に接続されている）、結果的にスロットから放出される電磁波の分布を制御することができる。
【００６２】
（変形例４）
この変形例４では、図１１に示すように、通路１１内の各スロット１０の上部に、当該スロット１０に対して対称形状な曲面を有する誘電体レンズ１７が設けられている。この曲面形状としては、スロット１０の形状・サイズ及び放出するマイクロ波に応じて、球面、非球面（楕円状、双曲線状等）、矩形の組み合わせとすればよく、図示の例では球面の場合を示す。この誘電体レンズ１７として適用可能なものとしては、ゾーンニングレンズをはじめマイクロ波に対するレンズ効果を奏する全ての構造を含む。
【００６３】
誘電体レンズ１７は、マイクロ波の波面形状の均一化を行なう際に、スロット１０を通過するマイクロ波の行路差による位相ずれを解消するような誘電率及び前記曲面形状をもつものである。通常マイクロ波は誘電体中を伝搬する際にはその速度が真空（又は空気中）に比して遅くなるため、誘電体レンズ１７を上記の如き構成に設計することで、行路差に比例して波面を調整することができ、均一化が可能となる。
【００６４】
この場合、生成されるプラズマにおける反射を考慮し、多重反射を見込んで誘電率及び前記曲面形状の最適化を図ることが好適である。または、反射を最小とするために誘電体レンズ１７のレンズ厚をλg ／２の整数倍（レンズ前後の誘電体の誘電率が両者共に高い／低いとき）、あるいはλg ／４の奇数倍（その他のとき）とすることが望ましい。
【００６５】
更に、変形例４の他の形態を図１２（図１１と同様の平面図）に示す。これは、誘電体レンズ１８を各スロット１０の直上ではなく、通路１１内で所定距離離間させて配し、その曲面形状を非球面とした一例である。
【００６６】
なお、図１１及び図１２において、通路１１内に誘電体が充填された場合には、誘電体レンズ１７，１８を用いる代わりに、誘電体レンズ１７，１８の形状の空隙を通路１１内に誘電体に形成することで、同様の効果を奏することができることは言うまでもない。
【００６７】
（変形例５）
この変形例５では、図１３（ａ），図１３（ｂ）（図３（ａ），図３（ｂ）と同様）に示すように、導波管１内に誘電体１９を充填する。ここで、λc を遮断周波数とすると、放出されるマイクロ波の波長λと管内波長λg との関係は、
【００６８】
【数２】

【００６９】
で表される。即ち、Ｅ面放射では、各スロット１０の間隔がλg 又はλg ／２であるため、導波管１に高誘電率の誘電体を充填すると、誘電体１９が強磁性体でなければ、誘電率の平方根に逆比例して波長λが小さくなり、管内波長λg のピッチが狭くなり、より均一なマイクロ波の放出が可能となる。
【００７０】
使用可能な誘電体としては、例えば、以下の表１に示すものが考えられる。但し、一般に誘電率が高くなると誘電損が大きくなるため、これを考慮して選択する必要がある。
【００７１】
【表１】

【００７２】
これらの誘電体を導波管１内に充填することで、導波管１内の管内波長は表１の比で記載された波長比で小さくなり、マイクロ波の波面の十分な均一化を図ることが可能となる。
【００７３】
（変形例６）
この変形例６では、より高い周波数、例えば２．４５ＧＨｚの導波管１でのピッチに対して２倍としたい場合には、４．９ＧＨｚ程度の周波数のマイクロ波を採用する。これにより、当該周波数に反比例して波長λが変化し、スロット１０のピッチを狭めることが可能となる。
【００７４】
（変形例７）
この変形例７では、導波管１のＨ面幅を可能な限り大きくする。励起周波数帯のマイクロ波が遮断されないような範囲で導波管１の遮断周波数λc を大きくするほど、管内波長λg は波長λに近づき、小さくなる。従って、例えば導波管１内をＴＥ１０モードのみ伝搬しているような場合、Ｈ面幅を可能な限り大きくすることで、スロット１０のピッチを狭めることが可能となる。ＴＥ１０モードのみ伝搬する条件は、Ｈ面幅をａとすると、
ａ＜λ（＜２ａ）
であることから、Ｈ面幅ａは、
（λ／２＜）ａ＜λ
で与えられる。ここで、（ ）内はＴＥ１０モードを通らない、即ち全てのモードのマイクロ波が伝搬し得ない条件を除くための条件である。従って、Ｈ面幅ａを波長λ程度に設定することで、ＴＥ２０モードを励起することなく管内波長λg が最小値２／３^1/2 λ（≒１．１５λ）に設定できる。なお、多モード励起を許容すると、管内波長λg は最小値λに漸近するが、その際にはａ→∞となるため現実的でない。
【００７５】
以上説明したように、本実施形態及びその諸変形例のエキシマレーザ発振装置によれば、スロットアレイ構造を採用するも、レーザ管の長手方向にわたり全体的に均一な電磁波の放射を実現し、エネルギー損失を極力抑えた均一なレーザ発光が可能となる。
【００７６】
（第２の実施形態）
以下、第２の実施形態について説明する。この第２の実施形態では、第１の実施形態で述べたエキシマレーザ発振装置をレーザ光源として有する露光装置（ステッパー）を例示する。図１４は、このステッパーの主要構成を示す模式図である。
【００７７】
このステッパーは、所望のパターンが描かれたレチクル１０１に照明光を照射するための光学系１１１と、レチクル１０１を介した照明光が入射して当該レチクル１０１のパターンをウェハ１０２の表面に縮小投影するための投影光学系１１２と、ウェハ１０２が載置固定されるウェハチャック１１３と、ウェハチャック１１３が固定されるウェハステージ１１４とを有して構成されている。
なお、レチクルとしては、図示の如く透過型のもの（レチクル１０１）のみならず、反射型のものも適用可能である。
【００７８】
光学系１１１は、照明光としての高輝度のエキシマレーザー光を発する光源である第１の実施形態のエキシマレーザ発振装置１２１と、光源１２１からの照明光を所望の光束形状に変換するビーム形状変換手段１２２と、複数のシリンドリカルレンズや微小レンズを２次元的に配置されてなるオプティカルインテグレータ１２３と、不図示の切替手段により任意の絞りに切替可能とされ、オプティカルインテグレータ１２３により形成された２次光源の位置近傍に配置された絞り部材１２４と、絞り部材１２４を通過した照明光を集光するコンデンサーレンズ１２５と、例えば４枚の可変ブレードにより構成され、レチクル１０１の共役面に配置されてレチクル１０１の表面での照明範囲を任意に決定するブラインド１２７と、ブラインド１２７で所定形状に決定された照明光をレチクル１０１の表面に投影するための結像レンズ１２８と、結像レンズ１２８からの照明光をレチクル１０１の方向へ反射させる折り曲げミラー１２９とを有して構成されている。
【００７９】
以上のように構成されたステッパーを用い、レチクル１０１のパターンをウェハ１０２の表面に縮小投影する動作について説明する。
【００８０】
先ず、光源１２１から発した照明光は、ビーム形状変換手段１２２で所定形状に変換された後、オプティカルインテグレータ１２３に指向される。このとき、その射出面近傍に複数の２次光源が形成される。この２次光源からの照明光が、絞り部材１２４を介してコンデンサーレンズ１２５で集光され、ブラインド１２７で所定形状に決定された後に結像レンズ１２８を介して折り曲げミラー１２９で反射してレチクル１０１に入射する。続いて、レチクル１０１のパターンを通過して投影光学系１２２に入射する。そして、投影光学系１２２を通過して前記パターンが所定寸法に縮小されてウェハ１０２の表面に投影され、露光が施される。
【００８１】
本実施形態のステッパーによれば、レーザ光源として第１の実施形態のエキシマレーザ発振装置を用いるので、高出力且つ均一なエキシマレーザ光の比較的長時間の発光が可能となり、ウェハ１０２に対する露光を迅速且つ正確な露光量で行なうことができる。
【００８２】
次に、図１４を用いて説明した投影露光装置を利用した半導体装置（半導体デバイス）の製造方法の一例を説明する。
【００８３】
図１５は、半導体デバイス（ＩＣやＬＳＩ等の半導体チップ、あるいは液晶パネルやＣＣＤ等）の製造工程のフローを示す。先ず、ステップ１（回路設計）では半導体デバイスの回路設計を行なう。ステップ２（マスク製作）では設計した回路パターンを形成したマスクを製作する。一方、ステップ３（ウェハ製造）ではシリコン等の材料を用いてウェハを製造する。ステップ４（ウェハプロセス）は前工程と称され、上記の如く用意したマスクとウェハを用いて、フォトリソグラフィー技術によってウェハ上に実際の回路を形成する。次のステップ５（組み立て）は後工程と称され、ステップ４によって作製されたウェハを用いて半導体チップ化する工程であり、アッセンプリ工程（ダイシング、ボンディング）、パッケージンク工程（チップ封入）等の工程を含む。ステップ６（検査）ではステップ５で作製された半導体デバイスの動作確認テスト、耐久性テスト等の検査を行う。こうした工程を経て半導体デバイスが完成し、これが出荷（ステップ７）される。
【００８４】
図１６は上記ウェハプロセスの詳細なフローを示す。ステップ１１（酸化）ではウェハの表面を酸化させる。ステップ１２（ＣＶＤ）ではウェハ表面に気相反応を用いて導電膜や絶縁膜を形成する。ステップ１３（ＰＶＤ）ではウェハ上に導電膜や絶縁膜をスパッタリングや蒸着によって形成する。ステップ１４（イオン打込み）ではウェハにイオンを打ち込む。ステップ１５（レジスト処理）ではウェハに感光剤を塗布する。ステップ１６（露光）では上記説明した投影露光装置によってマスクの回路パターンをウェハに焼付露光する。ステップ１７（現像）では露光したウェハを現像する。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）ではエッチングが終了して不要となったレジストを除去する。これらのステップを繰り返し行なうことによって、ウェハ上に多重に回路パターンが形成される。
【００８５】
この製造方法を用いれば、従来は製造が難しかった高集積度の半導体デバイスを容易且つ確実に高い歩止まりをもって製造することが可能となる。
【００８６】
【発明の効果】
本発明によれば、スロットアレイ構造を採用するも、レーザ管の長手方向にわたり全体的に均一な電磁波の放射が実現され、エネルギー損失を極力抑えた均一なレーザ発光が可能となる。
【図面の簡単な説明】
【図１】第１の実施形態によるエキシマレーザ発振装置の主要構成を示す模式図である。
【図２】導波管の具体的な様子を示す模式図である。
【図３】導波管の具体的な様子を示す概略断面図である。
【図４】導波管のスロット位置とマイクロ波により生じる電流密度との関係を示す模式図である。
【図５】スロットからマイクロ波が放出される様子を示す概略断面図である。
【図６】変形例１における導波管の具体的な様子を示す概略断面図である。
【図７】変形例２における導波管の具体的な様子を示す概略断面図である。
【図８】変形例２における導波管の具体的な様子を示す概略断面図である。
【図９】変形例３における導波管の具体的な様子を示す概略断面図である。
【図１０】変形例３における導波管の他の例の具体的な様子を示す概略平面図である。
【図１１】変形例４における導波管の具体的な様子を示す概略断面図である。
【図１２】変形例３における導波管の他の例の具体的な様子を示す概略断面図である。
【図１３】変形例５における導波管の具体的な様子を示す模式図である。
【図１４】第２の実施形態のステッパーを示す模式図である。
【図１５】第２の実施形態のステッパーを用いた半導体デバイスの製造工程のフロー図である。
【図１６】図１５におけるウェハプロセスを詳細に示すフロー図である。
【図１７】従来の導波管の具体的な様子を示す概略断面図である。
【符号の説明】
１ 導波管
２ レーザ管
５，６ 反射構造体
７ 冷却容器
８ レーザガス導入出口
９ 冷却水導入出口
１０ スロット
１１ 通路
１２ 金属壁
１３ 先端部位
１４ 誘電体
１５ 窓部
１６ 幅広部
１７，１８ 誘電体レンズ
１９ 誘電体
１０１ レチクル
１０２ ウェハ
１１１ 光学系
１１２ 投影光学系
１１３ ウェハチャック
１１４ ウェハステージ
１２１ エキシマレーザ発振装置
１２２ ビーム形状変換手段
１２３ オプティカルインテグレータ
１２４ 絞り部材
１２５ コンデンサーレンズ
１２７ ブラインド
１２８ 結像レンズ
１２９ 折り曲げミラー[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a laser oscillation device that generates laser light by introducing electromagnetic waves into a laser tube through a plurality of minute gaps formed on a waveguide wall from the waveguide, and particularly as an electromagnetic wave for laser gas excitation. It is suitable for application to a laser oscillation apparatus using a microwave, an exposure apparatus provided with the same, and a device manufacturing method.
[0002]
[Prior art]
In recent years, so-called excimer lasers have attracted attention as the only high-power lasers that oscillate in the ultraviolet region. Specifically, in the electronics industry, chemical industry, energy industry, etc., specifically metals, resins, glass, ceramics, semiconductors, etc. Applications are expected for processing and chemical reactions.
[0003]
The functional principle of the excimer laser oscillation device will be described. First, a laser gas such as Ar, Kr, Ne, or F ₂ filled in the manifold is brought into an excited state by electron beam irradiation or discharge. At this time, the excited F atoms are combined with inactive Kr and Ar atoms in the ground state to generate KrF ^* and ArF ^* which are molecules existing only in the excited state. This molecule is called an excimer. Excimer is unstable and immediately emits ultraviolet light and falls to the ground state. This is called bond-free transition or spontaneous light emission. Excimer laser oscillation device uses this excited molecule to amplify it as light with the same phase in an optical resonator composed of a pair of reflectors and extract it as laser light. It is.
[0004]
[Problems to be solved by the invention]
When excimer laser light is emitted, a microwave is mainly used as a laser gas excitation source as described above. The microwave is an electromagnetic wave having an oscillation frequency of several hundred MHz to several tens GHz. In this case, a microwave is introduced into the laser tube through a gap (slot) formed in the waveguide wall from the waveguide, thereby exciting the laser gas in the laser tube into a plasma state.
[0005]
Here, even if the intensity distribution of the microwaves emitted from the slots is uniform, in order to supply the microwaves to a space long enough to satisfy the resonator length of the laser beam, it is necessary to extend along the resonator major axis direction. Therefore, it is necessary to form a slot array structure in which a plurality of slots are arranged. This structure is shown in FIG. In FIG. 17, a plurality of minute gaps (slots) 202 are formed at equal intervals in the waveguide wall 201, and the inside of the laser tube is abbreviated as an emission space for convenience.
[0006]
When this slot array structure is adopted, an area between adjacent slots 202 (indicated by an elliptical shaded portion in FIG. 17) is necessarily a microwave non-irradiation area. Therefore, even when the laser gas existing in the emission space is excited by the microwave, the microwave intensity is uneven due to the presence of the non-irradiation region, and a plasma discharge having a non-uniform distribution as a whole is generated.
[0007]
The present invention has been made in view of the above problems, and adopts a slot array structure, but realizes uniform electromagnetic wave radiation over the longitudinal direction of the laser tube, and achieves uniform energy loss as much as possible. It is an object of the present invention to provide a laser oscillation apparatus capable of emitting laser light, a high-performance exposure apparatus equipped with the laser oscillation apparatus, and a high-quality device manufacturing method using the exposure apparatus.
[0008]
[Means for Solving the Problems]
The laser oscillation device of the present invention excites a laser gas in the laser tube by introducing a microwave into the laser tube through a plurality of minute gaps formed on the waveguide wall from the waveguide, and emits the laser gas. In the laser oscillation device that resonates light to generate laser light, a microwave path is formed by separating a predetermined distance from the minute gap to the laser tube wall, and from the minute gap to the laser tube wall. Is an integral multiple of a half wavelength of the microwave introduced from the waveguide, and a conductor is provided so as to surround the passage including the minute gap, and the passage is in contact with the laser tube. A gap having a predetermined width in the longitudinal direction of the laser tube is formed at the site, and the waveguide is filled with a dielectric .
[0013]
In one aspect of the laser oscillation device of the present invention, the width of the gap is an integral multiple of a half wavelength of the microwave introduced from the waveguide.
[0014]
In one aspect of the laser oscillation device of the present invention, the gap has a narrow width only at the tip portion, and has a slit shape extending in the longitudinal direction of the laser tube at the contact portion with the laser tube.
[0015]
In one aspect of the laser oscillation device of the present invention, the gap is wide only in the vicinity of the tip portion, and the width is substantially equal to the wavelength or half wavelength of the microwave introduced from the waveguide. Has been.
[0016]
In one aspect of the laser oscillation device of the present invention, the gap has a width in the vicinity of the tip portion that varies along the longitudinal direction of the gap, reflecting the intensity distribution of the microwave emitted from the minute gap. Has been.
[0019]
In one aspect of the laser oscillation apparatus of the present invention, the laser gas is at least one inert gas selected from Kr, Ar, and Ne, or a mixed gas of the at least one inert gas and F ₂ gas. An excimer laser oscillation device.
[0020]
The exposure apparatus of the present invention includes the laser oscillation device that is a light source that emits illumination light, a first optical system that irradiates illumination light from the laser oscillation device to a reticle on which a predetermined pattern is formed, and the reticle. A second optical system that irradiates the irradiated surface with illumination light, and projects a predetermined pattern of the reticle onto the irradiated surface for exposure.
[0021]
The device manufacturing method of the present invention includes a step of applying a photosensitive material to an irradiated surface, a step of exposing a predetermined pattern on the irradiated surface applied with the photosensitive material using the exposure apparatus, Developing the photosensitive material that has been exposed in a predetermined pattern.
[0022]
In one aspect of the device manufacturing method of the present invention, the irradiated surface is a wafer surface, and a semiconductor element is formed on the wafer surface.
[0023]
[Action]
In the laser oscillation device of the present invention, a space between the plurality of minute gaps (slots) formed on the waveguide wall and the laser tube wall is separated by a predetermined distance to form the electromagnetic wave passage. In this case, the wavefront of the electromagnetic wave emitted from each minute gap is flattened in the vicinity of the laser tube wall and propagates in the laser tube as a plane wave approximation as a whole. Therefore, an electromagnetic wave having a substantially uniform plane wave reaches the laser gas in the laser tube, and a uniform plasma discharge is realized in the longitudinal direction of the laser tube, contributing to uniform laser emission.
[0024]
Specifically, by setting the separation distance from the micro gap to the laser tube wall to be an integral multiple of half the wavelength of the electromagnetic wave introduced from the waveguide, the electromagnetic wave emitted from each micro gap becomes a reflected wave. It will reach the laser tube without interference and weakening.
[0025]
Further, by providing a conductor so as to surround the passage including the minute gap and making the passage a gap having a predetermined width, energy loss can be minimized. Alternatively, by setting the width of the electromagnetic wave to an integral multiple of a half wavelength, resonance conditions can be given in the vertical direction of the minute gap, and the electric field at the slit can be set high.
[0026]
Furthermore, by filling the gap with a dielectric, plasma generation in the passage can be suppressed, and plasma discharge can be reliably induced only in the laser tube.
[0027]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, specific embodiments to which the present invention is applied will be described in detail with reference to the drawings.
[0028]
(First embodiment)
First, the first embodiment will be described. In the present embodiment, an excimer laser oscillation device that emits so-called excimer laser light is exemplified.
FIG. 1 is a schematic diagram showing the main configuration of the excimer laser oscillation apparatus of the present embodiment.
[0029]
As shown in FIG. 1, the excimer laser oscillation apparatus is configured to excite an excimer laser gas in a laser tube 2 that emits laser light by resonating light emitted by excitation of an excimer laser gas, and to make a plasma state. In order to cool the waveguide 1 and the waveguide 1, a cooling vessel 7 having a cooling water inlet / outlet 9 is provided.
[0030]
The excimer laser gas used as a raw material for generating excimer laser light is one or more inert gases selected from Kr, Ar, and Ne, or a mixed gas of the one or more inert gases and F ₂ gas. is there. Of these, the gas species may be appropriately selected and combined depending on the wavelength to be used. For example, when it is desired to generate a laser beam having a wavelength of 248 nm, Kr / Ne / F ₂ is used. For a wavelength of 193 nm, Ar / Ne / F _{2 is used} . For a wavelength of 157 nm, Ne / F ₂ is used. do it.
[0031]
The laser tube 2 is provided with a laser gas inlet / outlet 8 serving as a portion for introducing an excimer laser gas into the tube, and reflection structures 5 and 6 at each end, respectively. Are aligned and laser light is generated.
[0032]
The waveguide 1 is means for supplying microwaves to the laser gas in the gas supply path structure 11, and a plurality of elongated slots 10 are formed on the upper surface portion in FIG. When a microwave having a frequency of several hundred MHz to several tens GHz is introduced from the upper part of the waveguide 1, the microwave is emitted from the slot 10 to the outside of the waveguide 1 while propagating through the waveguide 1. Is done. The emitted microwave is introduced into the laser tube 2 from a window portion 15 provided in the laser tube 2. The excimer laser gas in the laser tube 2 is excited by the introduced microwave and resonates to generate excimer laser light.
[0033]
In this embodiment, a conductor plate that separates the waveguide 1 from the region other than the region on the slot 10 between the waveguide wall and the laser tube wall by a predetermined distance, here a metal wall 12 (FIG. 2). Reference) is provided.
[0034]
A specific state of the waveguide 1 is shown in FIGS. 2A is a schematic perspective view of the waveguide 1, FIG. 2B is a plan view thereof, and FIG. 3A is a line segment II-II in FIG. 2B. FIG. 3B is a cross-sectional view taken along the line II ′ in FIG. 2B.
[0035]
As shown in FIG. 2 (b), the slots 10 are arranged in a row so that the longitudinal direction thereof coincides with the longitudinal direction of the waveguide 1, and the metal wall 12 surrounds the periphery of the slots 10. Is provided. As shown in FIGS. 3A and 3B, the metal wall 12 causes a gap across the entire waveguide 1 in the longitudinal direction of the laser tube 2 between the slot 10 and the window 15 on the laser tube wall. The gap is formed and becomes a microwave passage 11.
[0036]
In this example, the case where the slot 10 is formed on the so-called E-plane of the waveguide 1 is illustrated. When the slot 10 is formed on the H-plane, a passage corresponding to the portion where the slot 10 is formed is formed. It is necessary to provide a metal wall.
[0037]
Here, the distance from the slot 10 to the window portion 15 of the laser tube wall is an integral multiple of a half wavelength in the microwave tube introduced from the waveguide 1, that is, the wavelength in the microwave is λg, and n is an integer. As
d = n × λg / 2 (1)
It is set as the distance d represented by these.
Thereby, the passage 11 functions as a resonator, and the microwaves emitted from the slots 10 do not interfere with the reflected waves from the laser tube 2 and weaken each other.
[0038]
Note that the value of the integer n is arbitrary, but if it is too large, the loss due to absorption of the microwave into the metal wall 12 increases when the microwave propagates through the passage 11 as will be described later. It is not preferable. Therefore, it is most preferable to set the integer n to about 3 as will be described later.
[0039]
For the same reason, the width of the passage 11 is also an integral multiple of a half wavelength in the microwave tube introduced from the waveguide 1, that is,
w = n × λg / 2 (2)
The width w is expressed as follows.
[0040]
Hereinafter, the function of the waveguide 1 provided with the passage 11 will be described.
As the microwave propagates through the waveguide 1, a current flows through the waveguide wall. The microwave exists as a standing wave in the propagation space defined by the longitudinal distance of the waveguide 1, and the current on the waveguide wall also takes the form of a standing wave due to this standing wave. . However, the form of the standing wave of the microwave is three-dimensional and complicated, and it is convenient to consider the standing wave of the current of a general distributed constant line as an index.
[0041]
An example using the standing wave of the current as an index is shown in FIG. As described above, in this example, the slot 10 is arranged so that the formation site thereof corresponds to the abdominal part of the standing wave of the current (that is, the standing wave of the microwave). Therefore, as shown in FIG. 5, immediately after the wavefront of the microwave is emitted from the slot 10, it becomes a discontinuous curved surface shape corresponding to each slot 10 due to the array shape of each slot 10. Then, the microwaves gradually approach a plane wave by propagating from the slots 10 through the passages 11 restricted by the metal wall 12, and when the microwaves pass through the passages 11 and are emitted to the outside (that is, in the laser tube 2), The wavefront has a substantially planar shape throughout the entire slot 10.
[0042]
Therefore, the microwave that is a substantially uniform plane wave reaches the excimer laser gas in the laser tube 2, and a uniform plasma discharge is realized in the longitudinal direction of the laser tube 2, which contributes to uniform laser emission. .
[0043]
Here, a modified example of the present embodiment will be described. In addition, about the structural member etc. corresponding to embodiment, the same code | symbol is described and description is abbreviate | omitted.
[0044]
(Modification 1)
In this modified example 1, as shown in FIGS. 6A and 6B (each is a cross-sectional view similar to FIG. 3), the metal wall 12 is formed so that only the tip portion 13 of the passage 11 is narrow. Form. In this case, the distal end portion 13 of the passage 11 has a slit shape extending in the longitudinal direction of the laser tube 2 at the contact portion (that is, the window portion 15) with the laser tube 2.
[0045]
By forming the passage 11 in such a shape, it is possible to further suppress the unintentional dissipation of energy when the microwave is emitted into the laser tube 2.
[0046]
(Modification 2)
In the second modification, a dielectric 14 is provided so as to fill the inside of the passage 11 as shown in FIGS. 7 and 8, respectively, with respect to the structure of FIGS. 3 (a) and 6 (a). As a material for the dielectric 14, quartz, calcium fluoride, aluminum nitride, alumina, zirconia and the like are suitable.
[0047]
Filling the passage 11 with the dielectric 14 can prevent generation of plasma inside the passage 11. The dielectric 14 used at this time preferably has a high dielectric constant and a low dielectric loss in order to propagate microwaves more efficiently.
[0048]
Here, in order to simultaneously release a large amount of heat generated by the plasma to the outside at high speed, the dielectric 14 is required to have high thermal conductivity. Furthermore, in view of exposure to an atmosphere containing highly reactive F ₂ or the like such as an excimer laser, it is also important to have sufficient resistance against such a corrosive gas. Temporarily, the emission end of the microwave, that is, the surface in contact with the plasma is sputtered by ion irradiation of several to several hundreds eV (depending on the plasma potential) from the plasma in addition to the high temperature of 100 to 1000 ° C. (depending on the incident energy). The environment is extremely severe. Therefore, in some cases, AlN or alumina having high thermal conductivity and relatively high F ₂ resistance is used as the material of the dielectric 14, and its surface (interface with plasma) is made of CaF ₂ , LiF ₂ , MgF _{2 or} the like. By coating a few μm to several hundreds of μm of fluoride, it is possible to achieve both the same themes of heat conduction, corrosion gas resistance, and sputtering resistance.
[0049]
The energy loss in the passage 11 is roughly divided into two. That is, the dielectric loss in the filled dielectric and the loss in the drawing tube wall. The attenuation constant α due to dielectric loss is
α = ωμσ / 2β (3)
(Ω: angular frequency / μ: magnetic permeability / σ: electrical conductivity / β: phase constant).
Moreover, in the loss in the pipe wall, when focusing on the TE10 mode,
[0050]
[Expression 1]

[0051]
Given in. (Ξ: radio wave impedance / δ: skin depth) It is sufficient that the dominant loss of both is smaller than the energy supplied to the plasma, for example. That is, assuming that the microwave absorption rate in the plasma is r, r << 1 when the plasma is in a cutoff state,
Considering the round trip (multiple reflection) between the slot surface and the plasma interface,
exp (-2α · nλg / 2) <r (4)
The maximum length of the uniformized line can be defined using n satisfying
[0052]
However, in terms of the efficiency of the microwave, it is important to set the loss to be lower than the absorption rate r, and a design that reduces about 1/10 to 1/100 of r is preferable (such setting). By doing so, you can design a system with less loss.)
[0053]
Here, a specific experimental example when the dielectric 14 is filled in the passage 11 will be described below.
2.45 GHz Al alloy in which an E-plane emitting antenna having a = 42 mm, b = 21 mm, waveguide resonator length (longitudinal direction, ie, laser oscillation direction) of 220.8 mm, and a metal wall 12 disposed on the front surface of the slot A microwave irradiation antenna for the housing was manufactured. The waveguide resonator, that is, the passage 11, is filled with alumina having a dielectric constant of 9.8. At this time, the guide wavelength in the waveguide resonator is 44.2 mm. Therefore, the slot pitch is also set to 44.2 mm.
[0054]
The microwave emitted from the slot is emitted into the passage 11. This path 11 is approximately a parallel plate type waveguide, and under this approximation, the wavelength is equal to the wavelength in free space (however, inside the dielectric) is 39.1 mm. Actually, the waveguide 11 is a rectangular waveguide having a length of 235.3 mm in the laser oscillation direction of the passage 11 as a, but the guide wavelength at this time is 39.2 mm, which is 3.5 × 10 ⁻ as compared with the wavelength in free space. ^Since only about ³ changes, it is possible to use wavelength approximation of free space length in this structure. The half wavelength at this time is 19.6 mm, and the distance from the slot 10 surface of the passage 11 to the emission surface is 19.6 mm, 39.2 mm, 58.8 mm, etc. with respect to n: 1, 2, 3. Given.
[0055]
Here, the loss in the resonator is considered. Α due to dielectric loss is 5.22 × 10 ⁻⁷ dB / m when the resistance table of alumina is 10 ¹¹ Ω · cm, and the loss due to tube wall absorption is the resistivity of alumina of 2.65 × 10 ^{−. 6} Ω · cm is 0.234 dB / m. In this case, the dominant loss is the absorption of the pipe wall, so attention is paid to this. For every 19.6 mm traveled, a loss of 0.0053% occurs with respect to the energy propagating through the waveguide. Therefore, for example, in order to suppress the loss at the time of one reciprocation of the passage 11 to about 0.02% of the input energy, n is set to 3 which is smaller than 4 (loss: 0.21%) and can achieve the most uniform effect. did. Actually, since multiple reflection occurs, it is necessary to suppress to such a low loss level.
[0056]
(Modification 3)
In Modification 3, as shown in FIGS. 9A and 9B (cross-sectional views similar to FIGS. 3A and 3B), only the vicinity of the distal end portion 13 of the passage 11 is present. Wide, specifically, its half-value width α is
α = λg / 4
Or
α = λg / 2
The metal wall 12 is formed so that the passage 11 has a wide portion 16 that becomes the following.
[0057]
In this case, the wide portion 16 is formed so as to cover the entire region of the waveguide 1 in the longitudinal direction of the laser tube 2 following the path 11, and since the wide portion 16 is formed in the width as described above, The wide portion 16 can efficiently concentrate the energy of microwave resonance.
[0058]
A waveguide with this structure added to the waveguide having the structure described in Modification 2 was manufactured. At this time, α was designed to be 19.6 mm and 39 mm for λg / 4 and λg / 2, respectively, and the height of 16 was 5 mm. The thickness of the passage 11 is 4 mm. At this time, the energy present in 16 is 31.3% / 47.7% of the energy present in the passages 11 and 16, respectively. From this, the energy is concentrated in a portion close to the window portion 15 (ie, 16). I understand that In this comparison, it seems that the energy is more concentrated when α is λg / 2, but the energy of microwaves existing within a distance of λg / 4 from the center of 16 (that is, near slot 10). In the case where the energy existing in the passages 11 and 16 is 31.3% / 23.8%, respectively, and α is λg / 4, the effect of concentrating energy near the slot 10 is higher. I can say that.
[0059]
Furthermore, the other form of the modification 3 is shown in FIG. In this case, the width of the wide portion 16 is set to a different value along the longitudinal direction of the laser tube 2 reflecting the intensity distribution of the microwave emitted from the slot 10. That is, here, in addition to forming the passage 11 by providing the metal wall 12, in order to further homogenize the wavefront of the microwave, in order to further correct the homogenization of the passage 11 at the microwave emission site. A structure in which the width (or half-value width α) of the wide portion 16 is changed in accordance with the non-uniformity at the discharge site.
[0060]
As a result, a microwave with a more uniform plane wave reaches the excimer laser gas in the laser tube 2, and a uniform plasma discharge is realized over the longitudinal direction of the laser tube 2, thereby further uniformizing the laser emission. Contribute to.
[0061]
This effect is due to the characteristic property of the microwave that the characteristics of the propagation path can be changed by changing the shape of the spatial gap. The impedance Z of the terminal short-circuited waveguide having the length L characteristic impedance Z ₀ is
Z = jZ ₀ tan ((2π / λg) L)
It becomes. This means that inductive players (inductances and coils as discrete elements) and capacitive elements (capacitances and capacitors as discrete elements) having any value can be formed simply by changing L. . Changing the half-value width α in the slot line direction changes the impedance of the slot for the electromagnetic wave (in terms of an equivalent circuit, a coil having various values continuously with respect to the slot). As a result, the distribution of electromagnetic waves emitted from the slots can be controlled.
[0062]
(Modification 4)
In the fourth modification, as shown in FIG. 11, a dielectric lens 17 having a curved surface symmetrical with respect to the slot 10 is provided above each slot 10 in the passage 11. The curved surface shape may be a combination of a spherical surface, an aspherical surface (elliptical shape, hyperbolic shape, etc.), and a rectangular shape according to the shape and size of the slot 10 and the microwave to be emitted. Show. Examples of the dielectric lens 17 that can be applied include all structures that exhibit a lens effect on microwaves, including zoning lenses.
[0063]
The dielectric lens 17 has a dielectric constant and the curved surface shape so as to eliminate a phase shift due to a difference in path of the microwave passing through the slot 10 when the wavefront shape of the microwave is made uniform. Usually, when a microwave propagates in a dielectric, its speed is slower than that in vacuum (or in air). Therefore, the dielectric lens 17 is designed in the above-described configuration, and is proportional to the path difference. The wavefront can be adjusted to make it uniform.
[0064]
In this case, it is preferable to optimize the dielectric constant and the curved surface shape in consideration of the reflection in the generated plasma in consideration of multiple reflections. Alternatively, in order to minimize reflection, the lens thickness of the dielectric lens 17 is an integral multiple of λg / 2 (when the dielectric constant of the dielectric before and after the lens is both high / low), or an odd multiple of λg / 4 (others) Is desirable).
[0065]
Furthermore, the other form of the modification 4 is shown in FIG. 12 (the same plan view as FIG. 11). This is an example in which the dielectric lens 18 is arranged not at a position directly above each slot 10 but at a predetermined distance in the passage 11 and has a curved surface.
[0066]
11 and 12, when the dielectric is filled in the passage 11, instead of using the dielectric lenses 17 and 18, the gaps in the shape of the dielectric lenses 17 and 18 are formed in the dielectric. It goes without saying that the same effect can be achieved by forming the body.
[0067]
(Modification 5)
In Modification 5, as shown in FIGS. 13A and 13B (similar to FIGS. 3A and 3B), a dielectric 19 is filled in the waveguide 1. Here, if λc is a cutoff frequency, the relationship between the wavelength λ of the emitted microwave and the wavelength λg in the tube is
[0068]
[Expression 2]

[0069]
It is represented by That is, in the E-plane radiation, the interval between the slots 10 is λg or λg / 2. Therefore, when the waveguide 1 is filled with a dielectric having a high dielectric constant, the dielectric constant is determined unless the dielectric 19 is a ferromagnetic material. The wavelength λ becomes smaller in inverse proportion to the square root of λ, the pitch of the guide wavelength λg becomes narrower, and more uniform microwave emission becomes possible.
[0070]
Examples of usable dielectrics include those shown in Table 1 below. However, since the dielectric loss generally increases as the dielectric constant increases, it is necessary to select this in consideration.
[0071]
[Table 1]

[0072]
By filling these dielectrics in the waveguide 1, the in-tube wavelength in the waveguide 1 becomes small at the wavelength ratio described in the ratio of Table 1, and the wave front of the microwave is sufficiently uniformed. It becomes possible.
[0073]
(Modification 6)
In this modified example 6, when it is desired to double the pitch of the waveguide 1 at a higher frequency, for example, 2.45 GHz, a microwave having a frequency of about 4.9 GHz is employed. Thereby, the wavelength λ changes in inverse proportion to the frequency, and the pitch of the slots 10 can be narrowed.
[0074]
(Modification 7)
In this modified example 7, the H-plane width of the waveguide 1 is increased as much as possible. As the cutoff frequency λc of the waveguide 1 is increased within a range in which the microwaves in the excitation frequency band are not blocked, the guide wavelength λg approaches the wavelength λ and decreases. Therefore, for example, when only the TE10 mode is propagated in the waveguide 1, the pitch of the slots 10 can be reduced by increasing the H-plane width as much as possible. The condition for propagating only the TE10 mode is as follows:
a <λ (<2a)
Therefore, the H surface width a is
(Λ / 2 <) a <λ
Given in. Here, the values in () are conditions for excluding the condition that the TE10 mode does not pass, that is, the microwaves of all modes cannot propagate. Therefore, by setting the H-plane width a to about the wavelength λ, the guide wavelength λg can be set to the minimum value 2/3 ^1/2 λ (≈1.15λ) without exciting the TE20 mode. If multimode excitation is allowed, the guide wavelength λg gradually approaches the minimum value λ, but in that case, a → ∞, which is not practical.
[0075]
As described above, according to the excimer laser oscillation apparatus of the present embodiment and its various modifications, even though the slot array structure is adopted, it is possible to realize uniform radiation of electromagnetic waves over the longitudinal direction of the laser tube and Uniform laser emission with as little loss as possible is possible.
[0076]
(Second Embodiment)
Hereinafter, the second embodiment will be described. In the second embodiment, an exposure apparatus (stepper) having the excimer laser oscillation apparatus described in the first embodiment as a laser light source is exemplified. FIG. 14 is a schematic diagram showing the main configuration of this stepper.
[0077]
The stepper includes an optical system 111 for irradiating illumination light onto a reticle 101 on which a desired pattern is drawn, and illumination light incident through the reticle 101, and the pattern of the reticle 101 is reduced and projected onto the surface of the wafer 102. A projection optical system 112, a wafer chuck 113 on which the wafer 102 is placed and fixed, and a wafer stage 114 on which the wafer chuck 113 is fixed.
As the reticle, not only a transmission type (reticle 101) but also a reflection type can be applied as shown in the figure.
[0078]
The optical system 111 includes the excimer laser oscillation device 121 according to the first embodiment, which is a light source that emits high-luminance excimer laser light as illumination light, and beam shape conversion that converts illumination light from the light source 121 into a desired light beam shape. A secondary light source formed by the optical integrator 123, which can be switched to an arbitrary aperture by means 122, an optical integrator 123 in which a plurality of cylindrical lenses and microlenses are two-dimensionally arranged, and a switching means (not shown). The diaphragm member 124 is arranged near the position of the lens, the condenser lens 125 that collects the illumination light that has passed through the diaphragm member 124, and four variable blades, for example. Blind 127 that arbitrarily determines the illumination range on the surface of the screen, and Blind 1 7 has an imaging lens 128 for projecting the illumination light determined in a predetermined shape onto the surface of the reticle 101, and a folding mirror 129 for reflecting the illumination light from the imaging lens 128 in the direction of the reticle 101. It is configured.
[0079]
An operation for reducing and projecting the pattern of the reticle 101 onto the surface of the wafer 102 using the stepper configured as described above will be described.
[0080]
First, the illumination light emitted from the light source 121 is converted into a predetermined shape by the beam shape conversion unit 122 and then directed to the optical integrator 123. At this time, a plurality of secondary light sources are formed in the vicinity of the emission surface. Illumination light from the secondary light source is collected by the condenser lens 125 through the diaphragm member 124, and after being determined to have a predetermined shape by the blind 127, is reflected by the bending mirror 129 through the imaging lens 128 and reflected by the reticle 101. Is incident on. Subsequently, the light passes through the pattern of the reticle 101 and enters the projection optical system 122. Then, the pattern passes through the projection optical system 122, is reduced to a predetermined size, projected onto the surface of the wafer 102, and exposed.
[0081]
According to the stepper of the present embodiment, since the excimer laser oscillation apparatus of the first embodiment is used as a laser light source, high-power and uniform excimer laser light can be emitted for a relatively long time, and exposure to the wafer 102 can be performed. The exposure can be performed quickly and accurately.
[0082]
Next, an example of a method for manufacturing a semiconductor device (semiconductor device) using the projection exposure apparatus described with reference to FIG. 14 will be described.
[0083]
FIG. 15 shows a flow of a manufacturing process of a semiconductor device (a semiconductor chip such as an IC or LSI, or a liquid crystal panel or a CCD). First, in step 1 (circuit design), a semiconductor device circuit is designed. In step 2 (mask production), a mask on which the designed circuit pattern is formed is produced. On the other hand, in step 3 (wafer manufacture), a wafer is manufactured using a material such as silicon. Step 4 (wafer process) is called a pre-process, and an actual circuit is formed on the wafer by photolithography using the mask and wafer prepared as described above. The next step 5 (assembly) is referred to as a post-process, and is a process for forming a semiconductor chip using the wafer produced in step 4, and is a process such as an assembly process (dicing, bonding), a packaging process (chip encapsulation), etc. including. In step 6 (inspection), the semiconductor device manufactured in step 5 undergoes inspections such as an operation confirmation test and a durability test. Through these steps, the semiconductor device is completed and shipped (step 7).
[0084]
FIG. 16 shows a detailed flow of the wafer process. In step 11 (oxidation), the wafer surface is oxidized. In step 12 (CVD), a conductive film or an insulating film is formed on the wafer surface using a vapor phase reaction. In step 13 (PVD), a conductive film or an insulating film is formed on the wafer by sputtering or vapor deposition. In step 14 (ion implantation), ions are implanted into the wafer. In step 15 (resist process), a photosensitive agent is applied to the wafer. In step 16 (exposure), the circuit pattern of the mask is printed on the wafer by exposure using the projection exposure apparatus described above. In step 17 (development), the exposed wafer is developed. In step 18 (etching), portions other than the developed resist image are removed. In step 19 (resist stripping), the resist that has become unnecessary after etching is removed. By repeating these steps, multiple circuit patterns are formed on the wafer.
[0085]
By using this manufacturing method, it is possible to easily and surely manufacture a highly integrated semiconductor device that has been difficult to manufacture with high yield.
[0086]
【The invention's effect】
According to the present invention, even when a slot array structure is employed, uniform electromagnetic wave radiation is realized as a whole over the longitudinal direction of the laser tube, and uniform laser emission with minimized energy loss is possible.
[Brief description of the drawings]
FIG. 1 is a schematic diagram showing a main configuration of an excimer laser oscillation device according to a first embodiment.
FIG. 2 is a schematic diagram showing a specific state of a waveguide.
FIG. 3 is a schematic cross-sectional view showing a specific state of a waveguide.
FIG. 4 is a schematic diagram showing a relationship between a slot position of a waveguide and a current density generated by a microwave.
FIG. 5 is a schematic cross-sectional view showing how microwaves are emitted from slots.
6 is a schematic cross-sectional view showing a specific state of a waveguide according to Modification 1. FIG.
7 is a schematic cross-sectional view showing a specific state of a waveguide according to Modification 2. FIG.
FIG. 8 is a schematic cross-sectional view showing a specific state of a waveguide in a second modification.
FIG. 9 is a schematic cross-sectional view showing a specific state of a waveguide according to Modification 3.
FIG. 10 is a schematic plan view showing a specific state of another example of the waveguide in Modification 3.
FIG. 11 is a schematic cross-sectional view showing a specific state of a waveguide in a fourth modification.
12 is a schematic cross-sectional view showing a specific state of another example of the waveguide in Modification 3. FIG.
FIG. 13 is a schematic diagram showing a specific state of a waveguide in a fifth modification.
FIG. 14 is a schematic diagram showing a stepper according to a second embodiment.
FIG. 15 is a flowchart of a semiconductor device manufacturing process using the stepper of the second embodiment.
16 is a flowchart showing the wafer process in FIG. 15 in detail.
FIG. 17 is a schematic sectional view showing a specific state of a conventional waveguide.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Waveguide 2 Laser tube 5, 6 Reflective structure 7 Cooling container 8 Laser gas introduction exit 9 Cooling water introduction exit 10 Slot 11 Passage 12 Metal wall 13 Tip part 14 Dielectric 15 Window part 16 Wide part 17, 18 Dielectric lens 19 Dielectric 101 Reticle 102 Wafer 111 Optical system 112 Projection optical system 113 Wafer chuck 114 Wafer stage 121 Excimer laser oscillation device 122 Beam shape conversion means 123 Optical integrator 124 Aperture member 125 Condenser lens 127 Blind 128 Imaging lens 129 Bending mirror

Claims (9)

A microwave is introduced into the laser tube through a plurality of minute gaps formed on the waveguide wall from the waveguide, thereby exciting the laser gas in the laser tube and resonating the light emitted from the laser gas to emit the laser light. In the laser oscillation device to be generated,
A microwave path is formed with a predetermined distance from the minute gap to the laser tube wall, and the distance from the minute gap to the laser tube wall is the distance of the microwave introduced from the waveguide. It is an integral multiple of a half wavelength, and a conductor is provided so as to surround the passage including the minute gap, and the passage is a gap having a predetermined width in the longitudinal direction of the laser tube at a contact portion with the laser tube. A laser oscillation apparatus , wherein the waveguide is filled with a dielectric . The width of the gap is, the laser oscillation apparatus according to claim 1, characterized in that an integer multiple of the half wavelength of the microwave introduced from the waveguide. The gap, the tip section only are the narrow, according to claim 1 or 2, characterized in that there is a slit over the longitudinal direction of the laser tube at the site of contact with the laser tube Laser oscillation device. The gap is only the tip portion near are wider, claim 1, characterized in that said width is substantially equal to the wavelength or half wavelength of the microwaves introduced from the waveguide The laser oscillation apparatus of any one of -3 . The voids claim 1, the width of the distal end portion vicinity, characterized in that reflects the microwave intensity distribution emitted from the small gap are different values along the longitudinal direction of the gap The laser oscillation apparatus of any one of -3 . It is an excimer laser oscillation device using the laser gas as at least one inert gas selected from Kr, Ar, Ne or a mixed gas of the at least one inert gas and F ₂ gas. The laser oscillation device according to any one of claims 1 to 5 . It is a light source which emits illumination light, The laser oscillation apparatus of any one of Claims 1-5 ,
A first optical system that irradiates illumination light from the laser oscillation device onto a reticle having a predetermined pattern;
A second optical system for irradiating the illuminated surface with illumination light via the reticle,
An exposure apparatus that performs exposure by projecting a predetermined pattern of the reticle onto the irradiated surface. Applying a photosensitive material to the irradiated surface;
Using the exposure apparatus according to claim 7 to perform exposure of a predetermined pattern on the irradiated surface to which the photosensitive material is applied; and
And a step of developing the photosensitive material that has been exposed to the predetermined pattern. The device manufacturing method according to claim 8 , wherein the irradiated surface is a wafer surface, and a semiconductor element is formed on the wafer surface.

Images