JP3244076B2 - Exposure apparatus and method, and method of manufacturing semiconductor element - Google Patents

Exposure apparatus and method, and method of manufacturing semiconductor element

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Publication number
JP3244076B2
JP3244076B2 JP20679499A JP20679499A JP3244076B2 JP 3244076 B2 JP3244076 B2 JP 3244076B2 JP 20679499 A JP20679499 A JP 20679499A JP 20679499 A JP20679499 A JP 20679499A JP 3244076 B2 JP3244076 B2 JP 3244076B2
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JP
Japan
Prior art keywords
light
pattern
optical system
illumination
optical axis
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
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JP20679499A
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Japanese (ja)
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JP2000036460A (en
Inventor
直正 白石
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Nikon Corp
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Nikon Corp
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Classifications

    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03F—PHOTOMECHANICAL PRODUCTION OF TEXTURED OR PATTERNED SURFACES, e.g. FOR PRINTING, FOR PROCESSING OF SEMICONDUCTOR DEVICES; MATERIALS THEREFOR; ORIGINALS THEREFOR; APPARATUS SPECIALLY ADAPTED THEREFOR
    • G03F7/00—Photomechanical, e.g. photolithographic, production of textured or patterned surfaces, e.g. printing surfaces; Materials therefor, e.g. comprising photoresists; Apparatus specially adapted therefor
    • G03F7/70—Microphotolithographic exposure; Apparatus therefor
    • G03F7/70216—Mask projection systems

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  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Exposure Of Semiconductors, Excluding Electron Or Ion Beam Exposure (AREA)
  • Exposure And Positioning Against Photoresist Photosensitive Materials (AREA)

Description

【発明の詳細な説明】DETAILED DESCRIPTION OF THE INVENTION

【０００１】[0001]

【発明の属する技術分野】本発明は、半導体集積回路の
製造工程、特に半導体回路パターンの転写に利用される
投影型露光装置に関するものである。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a process for manufacturing a semiconductor integrated circuit, and more particularly to a projection exposure apparatus used for transferring a semiconductor circuit pattern.

【０００２】[0002]

【従来の技術】半導体メモリや液晶素子の回路パターン
の形成には、一般的に、フォトリソグラフ技術と呼ばれ
るマスクパターンを試料基板上に転写する方法が採用さ
れる。ここでは、所定のパターンが形成されたマスクを
紫外線等の露光光で照射し、そのパターン像を投影光学
系を介して、試料基板上の感光レジスト層に結像投影す
るものである。2. Description of the Related Art A method of transferring a mask pattern onto a sample substrate, which is called a photolithographic technique, is generally used for forming a circuit pattern of a semiconductor memory or a liquid crystal element. Here, a mask on which a predetermined pattern is formed is irradiated with exposure light such as ultraviolet rays, and the pattern image is formed and projected on a photosensitive resist layer on a sample substrate via a projection optical system.

【０００３】解像可能なマスクパターン（特にライン・
アンド・スペース）のピッチは露光波長と投影光学系の
開口数でほぼ決まり、レンズ材料やレジスト材料等の制
約から露光波長の短波長化にも限界があり、焦点深度の
制約から投影光学系の開口数の増大化にも限界があっ
た。また、従来においてもマスクパターンで生じる回折
光を積極的に利用して投影光学系の解像度を向上する技
術として、パターンの透過部の１つおきに露光光の位相
を反転させる誘電体、所謂位相シフターを設ける技術が
報告されている。しかしながら複雑な半導体回路パター
ン上に位相シフターを設けることは現実には難しく、位
相シフター付フォトマスクの検査方法も未だに確立され
ていない。[0003] Resolvable mask patterns (particularly lines and
The pitch of the projection optical system is almost determined by the exposure wavelength and the numerical aperture of the projection optical system, and there is a limit to shortening the exposure wavelength due to the limitations of the lens material and resist material. There is also a limit to increasing the numerical aperture. Conventionally, as a technique for improving the resolution of a projection optical system by positively utilizing diffracted light generated by a mask pattern, a dielectric material that inverts the phase of exposure light at every other transmission portion of a pattern, a so-called phase Techniques for providing shifters have been reported. However, it is actually difficult to provide a phase shifter on a complicated semiconductor circuit pattern, and a method for inspecting a photomask with a phase shifter has not yet been established.

【０００４】[0004]

【発明が解決しようとする課題】従来この種の装置にお
いては、図１０に示す如く照明光束Ｌ１０は、照明光学
系の瞳面付近に、投影光学系２９の瞳３２とほぼ共役に
配置されたほぼ円形の開口絞り１６ｄにより照明光学系
の光軸を中心とする円形領域内を通る光束Ｌ１１となっ
てレチクル（マスク）２７ｂを照明していた。ここで、
光束を表す実線は１点から出た光の主光線を表してい
る。Conventionally, in this type of apparatus, as shown in FIG. 10, an illumination light beam L10 is disposed near a pupil plane of an illumination optical system and almost conjugate with a pupil 32 of a projection optical system 29. The substantially circular aperture stop 16d illuminates the reticle (mask) 27b as a light flux L11 passing through a circular area centered on the optical axis of the illumination optical system. here,
A solid line representing a light flux represents a principal ray of light emitted from one point.

【０００５】このとき、照明光学系の開口数と投影光学
系２９のレチクル側開口数の比、所謂σ値は開口絞りに
より決定され、その値は０．３〜０．６程度が一般的で
ある。照明光Ｌ１１はレチクル２７ｂにパターニングさ
れたパターン２８ｂにより回折され、パターン２８ｂか
らは０次回折光Ｄｏ、＋１次回折光Ｄｒ、−１次回折光
Ｄｌが発生する。それぞれの回折光は投影光学系２９に
より集光されウェハ（試料基板）３０上に干渉縞を発生
させる。この干渉縞がパターン２８ｂの像である。At this time, the ratio between the numerical aperture of the illumination optical system and the numerical aperture on the reticle side of the projection optical system 29, the so-called σ value, is determined by the aperture stop, and the value is generally about 0.3 to 0.6. is there. The illumination light L11 is diffracted by the pattern 28b patterned on the reticle 27b, and the pattern 28b generates a 0th-order diffracted light Do, a + 1st-order diffracted light Dr, and a -1st-order diffracted light Dl. The respective diffracted lights are condensed by the projection optical system 29 and generate interference fringes on the wafer (sample substrate) 30. This interference fringe is an image of the pattern 28b.

【０００６】このとき、０次回折光Ｄｏと±１次回折光
Ｄｒ、Ｄｌとのなす角θはｓｉｎθ＝λ／Ｐ（λ：露光
波長、Ｐ：パターンピッチ）により決まる。パターンピ
ッチが微細化するとｓｉｎθが大きくなり、ｓｉｎθが
投影光学系のレチクル側開口数（ＮＡR）より大きくな
ると±１次回折光Ｄｒ、Ｄｌは投影光学系に入射できな
くなる。At this time, the angle θ between the zero-order diffracted light Do and the ± first-order diffracted lights Dr and Dl is determined by sin θ = λ / P (λ: exposure wavelength, P: pattern pitch). When the pattern pitch becomes finer, sin θ becomes larger. When sin θ becomes larger than the reticle-side numerical aperture (NA R ) of the projection optical system, the ± first-order diffracted lights Dr and Dl cannot enter the projection optical system.

【０００７】このとき、ウェハ３０上には０次回折光Ｄ
ｏのみしか到達せず干渉縞は生じない。つまり、ｓｉｎ
θ＞ＮＡRとなる場合にはパターン２８ｂの像は得られ
ず、パターン２８ｂをウェハ３０上に転写することがで
きなくなってしまう。以上より従来の露光装置において
は、ｓｉｎθ＝λ／Ｐ≒ＮＡRとなるピッチＰは次式で
与えられ、 Ｐ≒λ／ＮＡR ・・・（１） このピッチＰがウェハ３０上に転写可能となるパターン
のレチクル上での最小ピッチである。従って、上記
（１）式を満たすピッチよりも微細なピッチを有するパ
ターンは解像できないという問題点があった。又、焦点
深度は±λ／２(ＮＡw)2程度となっていた。（ＮＡwは
ウェハ側開口数）一方、位相シフトレチクルも限界解像
を上げる方法であるが、製造工程が複雑であり、従って
コストも高く、又検査方法も確立されていないなど多く
の問題が残されている。At this time, the zero-order diffracted light D
Only o arrives and no interference fringes occur. That is, sin
If θ> NA R , an image of the pattern 28b cannot be obtained, and the pattern 28b cannot be transferred onto the wafer 30. As described above, in the conventional exposure apparatus, the pitch P at which sin θ = λ / P ≒ NA R is given by the following equation: P ≒ λ / NA R (1) This pitch P can be transferred onto the wafer 30. Is the minimum pitch of the pattern on the reticle. Therefore, there is a problem that a pattern having a finer pitch than the pitch satisfying the above equation (1) cannot be resolved. Further, the depth of focus was about ± λ / 2 (NAw) 2 . (NAw is the numerical aperture on the wafer side.) On the other hand, the phase shift reticle is also a method of increasing the limit resolution, but the manufacturing process is complicated, the cost is high, and there are still many problems such as no inspection method established. Have been.

【０００８】本発明は以上の点を考慮してなされたもの
で、従来試料基板上で十分に解像できなかった微細なパ
ターンを従来のレチクルを使用して光量損失を少なく、
かつ、高解像度でウェハ上に転写する露光装置を得るこ
とを目的としている。又、高コントラストを保ったまま
焦点深度を上げることを目的とする。The present invention has been made in view of the above points, and reduces a light amount loss by using a conventional reticle to reduce a fine pattern which could not be sufficiently resolved on a conventional sample substrate.
It is another object of the present invention to obtain an exposure apparatus for transferring images onto a wafer with high resolution. Another object is to increase the depth of focus while maintaining high contrast.

【０００９】[0009]

【課題を解決するための手段】かかる問題点を解決する
ため本発明においては、マスクに照明光を照射する照明
光学系と、照明光を基板上に投射する投影光学系とを備
え、照明光の照射によってマスクのパターンを基板上に
転写する露光装置において、マスクパターンの微細度に
応じた角度だけ投影光学系の光軸に対して傾いてマスク
に入射するように、照明光を互いに異なる方向に進む複
数の光束に変換する偏向部材を設ける。According to the present invention, there is provided an illumination optical system for illuminating a mask with illumination light, and a projection optical system for projecting the illumination light onto a substrate. In an exposure apparatus that transfers a mask pattern onto a substrate by irradiation of light, illumination light is directed in different directions so that the light is incident on the mask at an angle corresponding to the degree of fineness of the mask pattern with respect to the optical axis of the projection optical system. A deflecting member for converting the light beam into a plurality of light beams is provided.

【００１０】[0010]

【作用】従来の投影型露光装置では、レチクルに対して
上方から種々の入射角で入射する露光光が無差別に用い
られ、レチクルパターンで発生した０次、±１次、±２
次、・・・の各回折光がほぼ無制限に投影光学系を透過
してウェハ上に結像していた。In the conventional projection type exposure apparatus, exposure light incident on the reticle from above at various incident angles is used indiscriminately, and the 0th order, ± 1st order, ± 2th order generated in the reticle pattern are used.
Next, each of the diffracted lights transmitted through the projection optical system almost indefinitely to form an image on the wafer.

【００１１】これに対して、本発明の投影型露光装置で
は、図９の如く照明光Ｌ１０から照明光学系中のレチク
ルパターン面と略共役な面に設けられた光束変換部材
（回折格子状パターン等の周期構造パターンが形成され
た光透過性平板、ウォラストンプリズム等）により照明
光学系の光軸上を通らない光束、つまりレチクルパター
ンに対して特定の方向と角度で斜めに入射する任意の２
つの光束Ｌ１２，Ｌ１３或いは２ｎ本（ｎは自然数）の
光束を発生させ、レチクルパターン２８ａを照明する。
レチクルパターン２８ａは通常光透過部と遮光部とが所
定のピッチで繰り返し形成された周期構造を有するパタ
ーンを多く含んでいる。そしてレチクルパターン２８ａ
で発生した０次回折光と±１次回折光とを投影光学系２
９を介してウェハ上に結像させる。On the other hand, according to the projection type exposure apparatus of the present invention, as shown in FIG. 9, a light beam conversion member (diffraction grating pattern) provided from illumination light L10 to a surface substantially conjugate with the reticle pattern surface in the illumination optical system. (A light-transmitting flat plate having a periodic structure pattern, such as a Wollaston prism), a light beam that does not pass on the optical axis of the illumination optical system, that is, any light obliquely incident on the reticle pattern at a specific direction and angle. 2
One light beam L12, L13 or 2n light beams (n is a natural number) is generated to illuminate the reticle pattern 28a.
The reticle pattern 28a includes many patterns having a periodic structure in which light transmitting portions and light shielding portions are repeatedly formed at a predetermined pitch. And the reticle pattern 28a
The 0th order diffracted light and ± 1st order diffracted light generated in
9 to form an image on the wafer.

【００１２】すなわち、レチクルパターン２８ａの微細
度に応じてパターン２８ａに所定の方向と角度で２本或
いは２ｎ本の光束を入射させることによって、最適な０
次回折光と±１次回折光を発生させることにより従来で
は十分に解像できなかったパターンをウェハ上に高コン
トラストに、かつ、大きい焦点深度を持って結像させる
ことが可能となる。ここで、レチクルに入射する光束
は、光束変換部材によって投影光学系の光軸ＡＸに対し
て対称に所定の角度ψだけ傾いて入射する主光線を有す
る２本の光束に変換されたものである。ここでも、光束
を表す実線は１点から出た光の主光線を表している。ま
ず図９に基づいて照明光Ｌ１２による回折光について説
明する。照明光Ｌ１２はレチクルパターン２８ａにより
回折され０次回折光Ｄｏ、＋１次回折光Ｄｒ、−１次回
折光Ｄｌを発生する。しかしながら、照明光Ｌ１２は投
影光学系２９の光軸ＡＸに対して角度ψだけ傾いてレチ
クルパターン２８ａに入射するので、０次回折光Ｄｏも
また投影光学系の光軸ＡＸに対して角度ψだけ傾いた方
向に進行する。That is, by irradiating two or 2n luminous fluxes at a predetermined direction and angle to the pattern 28a in accordance with the fineness of the reticle pattern 28a, an optimum 0
By generating the first-order diffracted light and the ± first-order diffracted light, it becomes possible to form a pattern that could not be resolved sufficiently in the past on a wafer with a high contrast and a large depth of focus. Here, the luminous flux incident on the reticle is converted into two luminous fluxes having chief rays incident symmetrically at a predetermined angle ψ with respect to the optical axis AX of the projection optical system by the luminous flux conversion member. . Again, the solid line representing the luminous flux represents the chief ray of the light emitted from one point. First, the diffracted light by the illumination light L12 will be described with reference to FIG. The illumination light L12 is diffracted by the reticle pattern 28a to generate a 0th-order diffracted light Do, a + 1st-order diffracted light Dr, and a -1st-order diffracted light Dl. However, since the illumination light L12 is incident on the reticle pattern 28a at an angle に 対 し て with respect to the optical axis AX of the projection optical system 29, the zero-order diffracted light Do is also inclined at an angle ψ with respect to the optical axis AX of the projection optical system. Proceed in the direction

【００１３】従って、＋１次回折光Ｄｒは光軸ＡＸに対
してθp＋ψの方向に進行し、−１次回折光Ｄｌは光軸
ＡＸに対してθm−ψの方向に進行する。このときθp、
θmはそれぞれ ｓｉｎ(θp＋ψ)−ｓｉｎψ＝λ／Ｐ・・・（２） ｓｉｎ(θm−ψ)＋ｓｉｎψ＝λ／Ｐ・・・（３） である。Accordingly, the + 1st-order diffracted light Dr travels in the direction of θp + に 対 し て with respect to the optical axis AX, and the -1st-order diffracted light Dl travels in the direction of θm-ψ with respect to the optical axis AX. At this time, θp,
θm is sin (θp + ψ) −sinψ = λ / P (2) sin (θm−ψ) + sinψ = λ / P (3)

【００１４】仮にいま＋１次回折光Ｄｒ、−１次回折光
Ｄｌの両方が投影レンズＰＬに入射しているとする。レ
チクルパターン２８ａの微細化に伴って回折角が増大す
ると、先ずθp＋ψの方向に進行する＋１次回折光Ｄｒ
が投影光学系２９に入射できなくなる（ｓｉｎ(θp＋
ψ)＞ＮＡRとなる）。しかし、照明光Ｌ１２が光軸ＡＸ
に対して傾いて入射している為、このときの回折角でも
−１次回折光Ｄｌは、入射投影光学系２９に入射可能と
なる（ｓｉｎ(θm−ψ)＜ＮＡRとなる）。Assume now that both the + 1st-order diffracted light Dr and the -1st-order diffracted light Dl are incident on the projection lens PL. When the diffraction angle increases with the miniaturization of the reticle pattern 28a, first, the + 1st-order diffracted light Dr traveling in the direction of θp + ψ
Cannot enter the projection optical system 29 (sin (θp +
ψ)> NA R ). However, the illumination light L12 has an optical axis AX
-1st-order diffracted light Dl can enter the incident projection optical system 29 even at the diffraction angle at this time (sin (θm− で も) <NA R ).

【００１５】従って、ウェハ３０上には０次回折光Ｄｏ
と−１次回折光Ｄｌの２光束による干渉縞が生じる。こ
の干渉縞はレチクルパターン２８ａの像でありレチクル
パターン２８ａが１：１のラインアンドスペースの時約
９０％のコントラストとなり、表面にレジストが塗布さ
れたウェハ上にパターン２８ａをパターニングすること
が可能となる。Therefore, the zero-order diffracted light Do
And interference fringes due to two light beams of the -1st-order diffracted light Dl. This interference fringe is an image of the reticle pattern 28a. When the reticle pattern 28a has a line and space ratio of 1: 1, the contrast becomes about 90%, and the pattern 28a can be patterned on a wafer having a surface coated with a resist. Become.

【００１６】このときの解像限界は、 ｓｉｎ(θm−ψ)＝ＮＡR ・・・（４） となるときであり、従って ＮＡR＋ｓｉｎψ＝λ／Ｐ Ｐ＝λ／ＮＡR＋ｓｉｎψ・・・（５） がレチクル上の転写可能な最小パターンのピッチであ
る。The resolution limit at this time is when sin (θm−ψ) = NA R (4), and therefore, NA R + sinψ = λ / PP = λ / NA R + sinψ. (5) is the minimum pattern pitch that can be transferred on the reticle.

【００１７】今ｓｉｎψを０．５×ＮＡR程度に定める
とすれば転写可能なレチクル上のパターンの最小ピッチ
は Ｐ＝λ／ＮＡR＋０．５ＮＡR＝２λ／３ＮＡR ・・・（６） である。一方、図１０に示す照明光が投影光学系９の光
軸ＡＸを中心とする円形領域内を通る光束である従来の
露光装置の場合、解像限界は（１）式に示したようにＰ
≒λ／ＮＡRであった。Assuming that sinψ is set to about 0.5 × NA R , the minimum pitch of the pattern on the reticle that can be transferred is P = λ / NA R + 0.5NA R = 2λ / 3NA R (6) It is. On the other hand, in the case of a conventional exposure apparatus in which the illumination light shown in FIG. 10 is a light beam passing through a circular area centered on the optical axis AX of the projection optical system 9, the resolution limit is P as shown in the equation (1).
≒ λ / NA R

【００１８】従って、従来の露光装置より高い解像度が
実現できる。照明光Ｌ１３についても同様に考えて、＋
１次回折光Ｄｒ1は光軸ＡＸに対してθp1−ψの方向に
進行し、−１次回折光Ｄｌ1は光軸ＡＸに対してθm1＋
ψの方向に進行する。Ｄｏ1は０次回折光を表してい
る。このときθp1、θm1はそれぞれ ｓｉｎ(θm1＋ψ)−ｓｉｎψ＝λ／Ｐ・・・（７） ｓｉｎ(θp1−ψ)＋ｓｉｎψ＝λ／Ｐ・・・（８） であり、解像限界はｓｉｎ(θp1−ψ)＝ＮＡRのときで
ある。Accordingly, a higher resolution than the conventional exposure apparatus can be realized. Considering the illumination light L13 similarly,
The first-order diffracted light Dr 1 travels in the direction of θp 1 −ψ with respect to the optical axis AX, and the −1st-order diffracted light Dl 1 is θm 1 + with respect to the optical axis AX.
Proceed in the direction of ψ. Do 1 represents the zero-order diffracted light. At this time, θp 1 and θm 1 are respectively sin (θm 1 + ψ) -sinψ = λ / P (7) sin (θp 1 -ψ) + sinψ = λ / P (8) The limit is when sin (θp 1 −ψ) = NA R.

【００１９】従って、照明光Ｌ１２の場合と同様に
（５）式に示すパターンピッチが転写可能なパターンの
最小ピッチとなる。照明光Ｌ１２とＬ１３の両方を使う
ことにより投影光学系の光軸に対して光量重心が偏らな
いようにしている。次に、レチクルパターンに対して特
定の入射方向と入射角で露光光を入射して、０次回折光
と１次回折光とを用いてウェハ上に結像パターンを形成
することにより、焦点深度が大きくなる理由を説明す
る。Therefore, similarly to the case of the illumination light L12, the pattern pitch shown in the equation (5) is the minimum pitch of a transferable pattern. By using both the illumination lights L12 and L13, the center of gravity of the light quantity is not deviated with respect to the optical axis of the projection optical system. Next, the exposure light is incident on the reticle pattern in a specific incident direction and an incident angle, and an imaging pattern is formed on the wafer using the 0th-order diffracted light and the 1st-order diffracted light, thereby increasing the depth of focus. The reason will be explained.

【００２０】ウェハが投影光学系の焦点位置に一致して
いる場合には、マスク上の１点を出てウェハ上の一点に
達する各回折光は、投影光学系のどの部分を通るもので
あってもすべて等しい光路長を有する。このため、従来
のように０次回折光が投影光学系の瞳面のほぼ中心を貫
通する場合でも、０次回折光とその他の回折光とで光路
長は相等しく、相互の波面収差も０である。しかし、ウ
ェハが投影光学系の焦点位置に一致していない場合、斜
めに入射する高次の回折光の光路長は光軸付近を通る０
次回折光に対して焦点前方（投影光学系から遠ざかる
方）では短く、焦点後方（投影光学系に近づく方）では
長くなりその差は入射角の差に応じたものとなる。従っ
て、０次、１次、・・・の各回折光は相互に波面収差を
形成して焦点位置の前後における結像パターンのぼけを
発生する。この波面収差ΔＷは、次式で表される。 ΔＷ＝１／２×（ＮＡ）2Δｆ Δｆ：デフォーカス量 ＮＡ：瞳面上の中心からの距離を開口数で表した値 従って、瞳面のほぼ中心を貫通する０次回折光（ΔＷ＝
０）に対して、瞳面の周囲、半径ｒ1（〔ＮＡ〕を単位
とする）を通る１次回折光では、 ΔＷ＝１／２×(ｒ1)2Δｆ の波面収差を持つこととなり、焦点位置の前後での解像
度、すなわち焦点深度を低くしている。一方、本発明の
投影型露光装置の場合、例えば図９の如くθm＝２ψと
なる入射角でレチクルパターン２８ａに２つの光束を入
射した場合、パターン２８ａからの０次回折光と１次回
折光とが瞳面上でほぼ中心から等距離となる位置（共に
半径ｒ2とする）を通るようになり０次回折光と１次回
折光の波面収差は相等しくΔＷ＝１／２×(ｒ2)2Δｆと
なり、０次回折光に対する１次回折光の収差は０とな
り、デフォーカスによるぼけが無くなる。この分だけ焦
点深度が大きくなっている。When the wafer coincides with the focal position of the projection optical system, each diffracted light that leaves one point on the mask and reaches one point on the wafer passes through any part of the projection optical system. All have the same optical path length. For this reason, even when the zero-order diffracted light penetrates substantially the center of the pupil plane of the projection optical system as in the related art, the optical path lengths of the zero-order diffracted light and the other diffracted lights are equal, and the mutual wavefront aberration is zero. . However, when the wafer does not coincide with the focal position of the projection optical system, the optical path length of the obliquely incident high-order diffracted light is 0 passing through the vicinity of the optical axis.
With respect to the next diffracted light, it is short before the focal point (away from the projection optical system) and long behind the focal point (approaching the projection optical system), and the difference depends on the difference in the incident angle. Therefore, the 0th-order, 1st-order,... Diffracted light mutually forms wavefront aberrations, and blurs the imaging pattern before and after the focal position. This wavefront aberration ΔW is expressed by the following equation. ΔW = 1/2 × (NA) 2 Δf Δf: Defocus amount NA: Value representing the distance from the center on the pupil plane as a numerical aperture Therefore, the 0th-order diffracted light (ΔW =
On the other hand, the first-order diffracted light passing through the radius r 1 (in units of [NA]) around the pupil plane has a wavefront aberration of ΔW = １ ／ × (r 1 ) 2 Δf with respect to 0). The resolution before and after the focal position, that is, the depth of focus is reduced. On the other hand, in the case of the projection type exposure apparatus of the present invention, when two light beams are incident on the reticle pattern 28a at an incident angle of θm = 2 °, for example, as shown in FIG. On the pupil plane, the light passes through a position which is almost equidistant from the center (both have a radius r 2 ), and the wavefront aberrations of the 0th-order diffracted light and the 1st-order diffracted light are equal, and ΔW = １ ／ × (r 2 ) 2 Δf Thus, the aberration of the first-order diffracted light with respect to the zero-order diffracted light becomes zero, and blurring due to defocus is eliminated. The depth of focus is increased by that much.

【００２１】以上照明光学系中のレチクルパターン面と
略共役な面に設けられた光束変換部材により照明光は回
折され照明光学系中の瞳面又は略瞳共役面においては照
明光学系の光軸を中心に対称な位置に上記回折光の±１
次回折光が集光される。またこの集光位置の変更は上記
光束変換部材の条件を変更（回折格子状パターンの形
状、ピッチの変更等）するだけで実現可能である。As described above, the illumination light is diffracted by the light beam conversion member provided on the surface substantially conjugate with the reticle pattern surface in the illumination optical system, and the optic axis of the illumination optical system in the pupil plane or the substantially pupil conjugate plane in the illumination optical system. ± 1 of the above diffracted light at symmetrical positions with respect to
Next-order diffracted light is collected. The change of the light condensing position can be realized only by changing the conditions of the light beam converting member (change of the shape of the diffraction grating pattern, the pitch, etc.).

【００２２】従って、照明光の光量を大幅に損失するこ
となく照明光学系の瞳面上で任意の照明光量分布を実現
することができ、レチクルパターン２８ａに応じた光束
をパターン２８ａに入射させることができる。このため
投影光学系に入射する光束の角度を所望の角度となるよ
うに調整可能となり、高い解像度をもち、かつ、光量損
失の少ない投影型露光装置を得ることができる。又光束
変換部材は照明光学系の瞳面又は略瞳共役面に光束のパ
ターン２８ａへの入射角に応じた任意形状の光量分布を
発生させる為のものなので、レチクルパターンとの相対
的位置関係の調整は不用である。Accordingly, it is possible to realize an arbitrary illumination light amount distribution on the pupil plane of the illumination optical system without largely losing the light amount of the illumination light, and to make the light flux corresponding to the reticle pattern 28a incident on the pattern 28a. Can be. For this reason, the angle of the light beam incident on the projection optical system can be adjusted to a desired angle, and a projection type exposure apparatus having a high resolution and a small loss of light amount can be obtained. The light beam conversion member is for generating a light quantity distribution of an arbitrary shape in accordance with the angle of incidence of the light beam on the pattern 28a on the pupil plane or the substantially pupil conjugate plane of the illumination optical system. No adjustment is necessary.

【００２３】以上のように構成すると光束変換部材とし
ての回折格子状パターンが照明光学系によりレチクルパ
ターン面に投影（結像）されて、不要な明暗の縞（回折
格子パターンの像）が生じる。この不要な明暗の縞は像
劣化手段により劣化（ホモナイズ）され、或いは時間的
に平均化されて像面光量分布上一様化され、レチクルパ
ターン面での照度むらの悪化を防止できる。With the above configuration, the diffraction grating pattern as the light beam conversion member is projected (imaged) on the reticle pattern surface by the illumination optical system, and unnecessary light and dark fringes (image of the diffraction grating pattern) are generated. The unnecessary light and dark fringes are degraded (homogenized) by the image degrading means, or averaged over time to make the distribution of the light amount on the image plane uniform, thereby preventing deterioration of the illuminance unevenness on the reticle pattern surface.

【００２４】以上本発明によれば、解像度の向上効果は
位相シフターに匹敵するものがありながら、従来のフォ
トマスクがそのまま使用でき、従来のフォトマスク検査
技術もそのまま踏襲することができる。更に、位相シフ
ターを採用すると、焦点深度が増大する効果も得られる
が、本発明においてもデフォーカスによる波面収差の影
響を受けにくくなるため、深い焦点深度（焦点裕度）が
得られる。According to the present invention, a conventional photomask can be used as it is, and a conventional photomask inspection technique can be followed as it is, although the effect of improving resolution is comparable to that of a phase shifter. Further, when the phase shifter is employed, the effect of increasing the depth of focus can be obtained. However, in the present invention, the depth of focus (focus latitude) can be obtained because the effect of wavefront aberration due to defocusing is reduced.

【００２５】[0025]

【発明の実施の形態】以下、図面を参照して本発明の実
施例について詳述する。図１は本発明の第１実施例によ
る投影型露光装置の全体構成図を示したものである。露
光用光源である水銀ランプ１から射出され楕円鏡２によ
り収束された光束Ｌ１はミラー３により反射されリレー
レンズ４を通り波長選択素子５により単色化される。単
色化された光束Ｌ２はミラー６で折り曲げられ、フライ
アイレンズ７に入射する。このときフライアイレンズ７
の入射面はレチクルパターン面２８と結像関係の位置に
ある。また、フライアイレンズ７の射出面は照明光学系
の１種の瞳面となっている。このフライアイレンズ７の
射出面近傍に開口絞り８が設けられている。そして開口
部の大きさを可変とする駆動部９により照明光Ｌ３の開
口数が決定される。照明光束Ｌ３はミラー１０により反
射されコンデンサーレンズ１１により回折格子状パター
ン１３ａが刻まれた光透過性平板１２を照明する。この
光透過性平板１２は本発明における光束変換部材として
機能するものであり、着脱及び交換可能となっている。
このとき光透過性平板１２はレチクル７に形成された微
細なレチクルパターン２８とほぼ結像関係の位置にあ
る。ここで、レチクルパターン２８は孤立パターンであ
ってもよく、又周期構造を持ったパターンであってもよ
い。Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 is an overall configuration diagram of a projection type exposure apparatus according to a first embodiment of the present invention. A light beam L1 emitted from a mercury lamp 1 as an exposure light source and converged by an elliptical mirror 2 is reflected by a mirror 3, passes through a relay lens 4, and is made monochromatic by a wavelength selection element 5. The monochromatic light beam L2 is bent by the mirror 6 and enters the fly-eye lens 7. At this time, the fly-eye lens 7
Is located in an image-forming relationship with the reticle pattern surface 28. The exit surface of the fly-eye lens 7 is a kind of pupil surface of the illumination optical system. An aperture stop 8 is provided near the exit surface of the fly-eye lens 7. Then, the numerical aperture of the illumination light L3 is determined by the driving unit 9 that makes the size of the opening variable. The illumination light beam L3 is reflected by the mirror 10 and illuminates the light transmitting flat plate 12 on which the diffraction grating pattern 13a is engraved by the condenser lens 11. The light-transmitting flat plate 12 functions as a light beam conversion member in the present invention, and is detachable and replaceable.
At this time, the light transmissive flat plate 12 is located at a position substantially in an imaging relationship with the fine reticle pattern 28 formed on the reticle 7. Here, the reticle pattern 28 may be an isolated pattern or a pattern having a periodic structure.

【００２６】図２は光透過性平板の一例を示す平面図で
ある。光透過性平板１２は石英ガラス等の透明基板であ
り、回折格子状パターン１３ａはＣｒ等の遮光性金属薄
膜で形成されているラインアンドスペースのパターンで
ある。尚、このとき、回折格子状パターン１３ａのピッ
チＰｇはレチクルパターン２８のピッチＰｒに対してＰ
ｇ＝２Ｐｒ×Ｍ（Ｍは回折格子状パターン１３ａとレチ
クルパターン２８間の結像倍率）程度であることが望ま
しい。そのデューティは必ずしも１：１である必要はな
く任意である。FIG. 2 is a plan view showing an example of a light-transmitting flat plate. The light transmissive flat plate 12 is a transparent substrate such as quartz glass, and the diffraction grating pattern 13a is a line-and-space pattern formed of a light-shielding metal thin film such as Cr. At this time, the pitch Pg of the diffraction grating pattern 13a is smaller than the pitch Pr of the reticle pattern 28 by P.
It is desirable that g = 2Pr × M (M is the imaging magnification between the diffraction grating pattern 13a and the reticle pattern 28). The duty does not necessarily have to be 1: 1 and is arbitrary.

【００２７】さて、図１の説明に戻って、回折格子状パ
ターン１３ａにより発生した−１次回折光Ｌ４及び＋１
次回折光Ｌ５は集光レンズ１５によりそれぞれ照明光学
系の光軸に対して対称となる照明光学系中の別の瞳面上
に集光される。この照明光学系の瞳面近傍に設けられた
空間フィルター１６は回折格子状パターン１３ａから発
生した回折光のうち特定の次数の回折光、本実施例では
±１次回折光Ｌ４，Ｌ５を透過するものである。尚、こ
の空間フィルター１６は透光部を可変可能とする可変型
フィルターでもよく、又着脱、交換可能なフィルターで
もよい。空間フィルター１６は、回折格子状パターン１
３ａから０次回折光が発生する場合は、その０次回折光
を遮光する大きさのＣｒ薄膜を設けた方がよい。また不
必要な次数の光を遮光することもできる。Returning to the description of FIG. 1, the -1st-order diffracted lights L4 and +1 generated by the diffraction grating pattern 13a are generated.
The next-order diffracted light L5 is condensed by the condenser lens 15 on another pupil plane in the illumination optical system that is symmetric with respect to the optical axis of the illumination optical system. A spatial filter 16 provided in the vicinity of the pupil plane of this illumination optical system transmits a specific order of diffracted light out of the diffracted light generated from the diffraction grating pattern 13a, that is, ± 1st order diffracted light L4, L5 in this embodiment. It is. It should be noted that the spatial filter 16 may be a variable filter capable of changing the light-transmitting portion, or may be a detachable / replaceable filter. The spatial filter 16 includes the diffraction grating pattern 1
When the 0th-order diffracted light is generated from 3a, it is better to provide a Cr thin film having a size that blocks the 0th-order diffracted light. Also, unnecessary orders of light can be blocked.

【００２８】図３は図２の如き回折格子状パターン１３
ａを使用したときに好適な空間フィルター１６ａを表
す。斜線部は遮光部でありその半径は照明光学系の全開
口数以上とする。中心点に対して対称に位置する２つの
白丸部は光透過部（開口部）を示している。ここで、必
要とされる照明光学系の瞳面での強度分布はレチクルパ
ターン２８の方向性によっても異なるが、回折格子状パ
ターン１３ａとしてはレチクルパターン２８と等しい方
向性（レチクルパターン２８に投影された回折格子状パ
ターン１３ａの方向性がレチクルパターンの大部分の方
向性と一致する。）であることが望ましい。またこれら
を実現するために、各レチクルパターン２８に対して決
められる固有の回折格子状パターンを各光透過性平板上
に刻んでおき、レチクル２７の交換時に同時に光透過性
平板をレチクルに合わせて交換すればよい。FIG. 3 shows a diffraction grating pattern 13 shown in FIG.
a represents a suitable spatial filter 16a when a is used. The shaded portion is a light-shielding portion, the radius of which is equal to or larger than the total numerical aperture of the illumination optical system. Two white circles located symmetrically with respect to the center point indicate light transmission parts (openings). Here, the required intensity distribution on the pupil plane of the illumination optical system differs depending on the directionality of the reticle pattern 28, but the diffraction grating pattern 13a has the same directionality as that of the reticle pattern 28 (projected onto the reticle pattern 28). It is preferable that the directionality of the diffraction grating pattern 13a matches the directionality of most of the reticle pattern.) To realize these, a unique diffraction grating pattern determined for each reticle pattern 28 is cut on each light transmitting flat plate, and the light transmitting flat plate is adjusted to the reticle at the same time when the reticle 27 is replaced. I just need to replace it.

【００２９】回折格子状パターン１３ａは、レチクルパ
ターン２８のピッチ或いは線幅及び方向性により決定さ
れるので、ピッチ或いは線幅のほぼ等しいパターンを有
する複数のレチクルに対しては、回折格子状パターン１
３ａの刻まれた同じ光透過性平板を共用してもよい。上
記複数のレチクルの方向性が異なる場合には回折格子状
パターン１３ａを面内で回転してレチクル上のパターン
の方向性に一致させればよい。又、イメージローテータ
でパターン１３ａの像を回転させてもよい。Since the diffraction grating pattern 13a is determined by the pitch or line width and directionality of the reticle pattern 28, the diffraction grating pattern 1a is not used for a plurality of reticles having a pattern having substantially the same pitch or line width.
The same light-transmitting flat plate engraved with 3a may be shared. When the directions of the plurality of reticles are different from each other, the diffraction grating pattern 13a may be rotated in a plane to match the direction of the pattern on the reticle. Further, the image of the pattern 13a may be rotated by an image rotator.

【００３０】例えば、図２のような回折格子状パターン
１３ａをレチクルパターン２８の方向性に従って任意の
角度となるように照明光学系の光軸を中心として回転さ
せた状態で使用してもよい。さて、図１に示すように、
空間フィルター１６を通過した光束Ｌ４，Ｌ５は集光レ
ンズ１９によりレチクルブラインド２０へ導かれる。レ
チクルブラインド２０はレチクルパターン面と結像関係
の位置にありレチクル２７上の特定エリアのみを照明す
るための視野絞りである。この視野絞りは駆動系２１に
より開閉可能となっており、レチクル２７上の照明エリ
アの大きさを調整可能となっている。レチクルブライン
ド２０を通過した光束Ｌ６、Ｌ７はコンデンサーレンズ
２２，２６及び略瞳面近傍に設けられたミラー２４を介
してレチクル２７を照明する。光束Ｌ６、Ｌ７がレチク
ルパターン２８に入射し、パターン２８から発生した回
折光は投影光学系２９によりウェハステージ３１上に置
かれたウェハ３０上に集光結像される。For example, the diffraction grating pattern 13a as shown in FIG. 2 may be used while being rotated about the optical axis of the illumination optical system so as to have an arbitrary angle in accordance with the directionality of the reticle pattern 28. Now, as shown in FIG.
The light beams L4 and L5 that have passed through the spatial filter 16 are guided to the reticle blind 20 by the condenser lens 19. The reticle blind 20 is a field stop for illuminating only a specific area on the reticle 27 at a position having an image forming relationship with the reticle pattern surface. The field stop can be opened and closed by a drive system 21 so that the size of the illumination area on the reticle 27 can be adjusted. The light beams L6 and L7 that have passed through the reticle blind 20 illuminate the reticle 27 via the condenser lenses 22 and 26 and the mirror 24 provided substantially near the pupil plane. The light beams L6 and L7 enter the reticle pattern 28, and the diffracted light generated from the pattern 28 is focused and imaged on a wafer 30 placed on a wafer stage 31 by a projection optical system 29.

【００３１】ここで、前述の如く光束Ｌ６、Ｌ７はレチ
クルパターン２８に投影光学系の光軸に対して互いに対
称に角度ψだけ傾いて入射し、パターン２８からは０次
回折光Ｄｏ、−１次回折光Ｄｌ、＋１次回折光Ｄｒが発
生する。入射角ψはレチクルパターン２８と投影光学系
の開口数ＮＡによって定められ、（５）式で示したよう
に、レチクルパターンピッチの最小値に対応した入射角
に選択される。入射の方向はレチクルパターンのピッチ
配列方向となるようにするのが望ましい。Here, as described above, the light beams L6 and L7 are incident on the reticle pattern 28 at an angle ψ symmetrically with respect to the optical axis of the projection optical system. Folded light Dl and + 1st-order diffracted light Dr are generated. The incident angle ψ is determined by the reticle pattern 28 and the numerical aperture NA of the projection optical system, and is selected to be the incident angle corresponding to the minimum value of the reticle pattern pitch, as shown in equation (5). It is desirable that the direction of incidence be the pitch arrangement direction of the reticle pattern.

【００３２】ここで、回折格子状パターン１３ａは照明
光学系によりレチクルパターン２８上に投影されるので
レチクルパターン２８上には回折格子状の明暗像が生
じ、照明光量の均一化を悪化させる。しかしながら、上
記回折格子状パターン１３ａの刻まれた光透過性平板１
２をモータ、ピエゾ等の駆動部材１４で１ショット当た
りの露光時間中（ウェハ３０に対して不図示のシャッタ
ーが開いている間）に回折格子状パターン１３ａの１ピ
ッチ又はその整数倍程度以上移動又は振動させる。これ
により、１ショット当たりの露光時間中に明暗像が１ピ
ッチ程度以上移動し明暗は時間的に平均化（ホモナイ
ズ）されるため照明光量の均一性は良好に保たれる。上
記明暗像の移動又は振動の方向は回折格子状パターン１
３の方向と相関性の少ないものがよい。例えばパターン
１３ａのピッチＰｇ以上を直径とする円運動（ｘ方向と
ｙ方向の振動の合成）をさせてもよい。Here, since the diffraction grating pattern 13a is projected on the reticle pattern 28 by the illumination optical system, a diffraction grating bright and dark image is generated on the reticle pattern 28, and the uniformity of the illumination light amount is deteriorated. However, the light transmitting flat plate 1 on which the diffraction grating pattern 13a is engraved is used.
2 is moved by a driving member 14 such as a motor or a piezo during the exposure time per shot (while a shutter (not shown) is opened with respect to the wafer 30), at least one pitch of the diffraction grating pattern 13a or an integer multiple thereof. Or vibrate. As a result, the bright and dark images move by about one pitch or more during the exposure time per shot, and the brightness is temporally averaged (homogenized), so that the uniformity of the illumination light amount can be kept good. The direction of movement or vibration of the bright and dark images is the diffraction grating pattern 1
The one having little correlation with the direction of 3 is preferable. For example, a circular motion (combination of vibrations in the x and y directions) having a diameter equal to or greater than the pitch Pg of the pattern 13a may be performed.

【００３３】このとき光透過性平板１２の代わりに照明
光学系内で、かつ、光透過性平板１２よりレチクル２７
に近い１つ以上の光学部材を同様の条件で移動、振動或
いは円運動させてもよい。図１中ではコンデンサーレン
ズ２２及びミラー２４に駆動部材２３，２５を付けた例
を示してある。At this time, the reticle 27 is placed in the illumination optical system instead of the light-transmitting flat plate 12 and from the light-transmitting flat plate 12.
One or more optical members close to may be moved, vibrated, or circularly moved under the same conditions. FIG. 1 shows an example in which drive members 23 and 25 are attached to the condenser lens 22 and the mirror 24.

【００３４】上記のような移動、振動或いは円運動を与
えることにより露光時間内に上記明暗像は平均化され
て、レチクルパターン２８上での照明光量は均一に保た
れる。しかしながら、回折格子状パターン１３ａの製造
誤差によるパターン面内の透過率のバラツキや回折効率
のバラツキにより、レチクルパターン面２８にて光量む
らが発生する可能性がある。これを防止するためにはレ
モンスキン等の拡散板などの光散乱部材１７を照明光学
系の瞳面近傍に設ければよい。By giving the above-mentioned movement, vibration or circular movement, the bright and dark images are averaged within the exposure time, and the amount of illumination on the reticle pattern 28 is kept uniform. However, unevenness in the amount of light may occur on the reticle pattern surface 28 due to variations in the transmittance in the pattern surface and variations in the diffraction efficiency due to manufacturing errors of the diffraction grating pattern 13a. In order to prevent this, a light scattering member 17 such as a diffusion plate such as a lemon skin may be provided near the pupil plane of the illumination optical system.

【００３５】光散乱部材１７により回折格子状パターン
１３ａ上の一点より出た光は、散乱されてレチクルパタ
ーン面２８の広い面積を照明することになる。これは、
換言するとレチクルパターン面２８上の一点には回折格
子状パターン１３ａの広い面積の部分からの光が到達す
ることになり、回折格子状パターン１３ａの局所的な製
造誤差は緩和される。このとき、光散乱部材１７を１シ
ョットの露光時間中にモータ１８等で移動、振動あるい
は回転させると時間的な平均化効果が生じ、より照明光
量のバラツキを除去し易い。Light emitted from one point on the diffraction grating pattern 13a by the light scattering member 17 is scattered and illuminates a wide area of the reticle pattern surface 28. this is,
In other words, light from a large area of the diffraction grating pattern 13a reaches one point on the reticle pattern surface 28, and local manufacturing errors of the diffraction grating pattern 13a are reduced. At this time, if the light scattering member 17 is moved, vibrated, or rotated by the motor 18 or the like during the exposure time of one shot, a time averaging effect occurs, and it is easier to remove the variation in the illumination light amount.

【００３６】尚、光散乱部材１７を移動、振動あるいは
回転させる場合、光透過性平板１２或いはコンデンサー
レンズ２２やミラー２４等の光学部材の移動、振動ある
いは回転は行わなくてもよい。瞳面近傍に設けられたこ
の光散乱部材１７は回折格子状パターン１３ａの像を劣
化させるが、レチクルパターン面２８に入射する照明光
の入射方向の角度範囲を極端に乱すことはない。When the light scattering member 17 is moved, vibrated or rotated, the light transmitting plate 12 or the optical members such as the condenser lens 22 and the mirror 24 need not be moved, vibrated or rotated. The light scattering member 17 provided near the pupil plane deteriorates the image of the diffraction grating pattern 13a, but does not extremely disturb the angle range of the incident direction of the illumination light incident on the reticle pattern surface.

【００３７】また、光散乱部材１７の代わりに瞳面上に
ファイバーの束を少なくともスポット光の大きさ以上に
或いは瞳面全体に敷き詰めて光束を劣化させるようにし
てもよい。更に、光散乱部材１７と併用すればより像劣
化の効果を高めることができる。本発明にかかる本実施
例による解像度向上の効果をより強くするために照明系
の開口絞り８を調整することによってσ＝０．２〜０．
３程度とすることが好ましい。これはσ値が大きすぎる
と解像度や焦点深度の向上が実現できず、小さすぎると
像の忠実度が低下する為である。Further, instead of the light scattering member 17, a bundle of fibers may be spread over at least the size of the spot light or spread over the entire pupil plane to degrade the light flux. Further, when used in combination with the light scattering member 17, the effect of image deterioration can be further enhanced. By adjusting the aperture stop 8 of the illumination system in order to further enhance the effect of improving the resolution according to the present embodiment according to the present invention, σ = 0.2 to 0.2.
It is preferred to be about 3. This is because if the σ value is too large, the resolution and the depth of focus cannot be improved, and if the σ value is too small, the fidelity of the image decreases.

【００３８】従って、照明光学系のフライアイレンズ７
の射出面積に対して０．３とするようにフライアイレン
ズ７そのものを作ることが望ましく、楕円鏡２からフラ
イアイレンズ７までの照明光学系はσ≒０．３に対して
光量を最大とする構成とするとよい。又、実施例中の各
ミラーの位置はこれに限定されるものではない。例え
ば、駆動部材２５付のミラー２４はレチクルブラインド
２０より空間フィルター１６側であってもよい。Therefore, the fly-eye lens 7 of the illumination optical system
It is desirable that the fly-eye lens 7 itself is made to be 0.3 with respect to the emission area of the lens, and the illumination optical system from the elliptical mirror 2 to the fly-eye lens 7 has the maximum light amount for σ ≒ 0.3. It is preferable to adopt a configuration in which Further, the position of each mirror in the embodiment is not limited to this. For example, the mirror 24 with the driving member 25 may be closer to the spatial filter 16 than the reticle blind 20.

【００３９】<<変形例>>次に回折格子状パターン１３ａ
の変形例について説明する。レチクルパターン２８の方
向がレチクル全面において均一ではなく部分的に異なる
方向を向いている場合には、図４に示すような部分的に
異なる方向に配列された回折格子状パターン１３ｂが形
成された光透過性平板１２を用いればよい。<< Modification >> Next, the diffraction grating pattern 13a
A modified example will be described. When the direction of the reticle pattern 28 is not uniform over the entire surface of the reticle but points in a partially different direction, the light having the diffraction grating patterns 13b arranged in partially different directions as shown in FIG. 4 is formed. What is necessary is just to use the transparent flat plate 12.

【００４０】図４ではレチクルパターン２８がｘ，ｙ２
方向に周期構造を持っている場合について示している。
回折格子状パターン１３ｂ１，１３ｂ３はｙ方向に周期
構造を持つレチクルパターン２８に対応するものであ
り、回折格子状パターン１３ｂ２，１３ｂ３はｘ方向に
周期構造を持つレチクルパターン２８に対応するもので
ある。このとき回折格子状パターン１３ｂ１〜１３ｂ４
のピッチ配列方向はレチクルパターン２８の方向と等し
くなるようにする。In FIG. 4, the reticle pattern 28 has x, y2
The case where a periodic structure is provided in the direction is shown.
The diffraction grating patterns 13b1 and 13b3 correspond to the reticle pattern 28 having a periodic structure in the y direction, and the diffraction grating patterns 13b2 and 13b3 correspond to the reticle pattern 28 having a periodic structure in the x direction. At this time, the diffraction grating patterns 13b1 to 13b4
Are arranged to be equal to the direction of the reticle pattern 28.

【００４１】図５は、図４の如き回折格子状パターン１
３ｂに対応する空間フィルター１６ｂを示した図であ
る。斜線部は遮光部を表し、白丸は光透過部（開口部）
を表す。光透過部１６０ａ、１６０ｃは回折格子状パタ
ーン１３ｂ１、１３ｂ３から生じる回折光を透過するも
のである。光透過部１６０ａと１６０ｂの間隔は回折格
子状パターン１３ｂ１、１３ｂ３のピッチにより決ま
る。空間フィルター１６での回折光の位置、つまり光透
過部１６０ａ、１６０ｃの位置によりレチクルパターン
に入射する回折光の方向、角度が決定する。FIG. 5 shows a diffraction grating pattern 1 shown in FIG.
FIG. 4 is a diagram showing a spatial filter 16b corresponding to 3b. The shaded area indicates the light shielding area, and the white circle indicates the light transmitting area (opening).
Represents The light transmitting portions 160a and 160c transmit the diffracted light generated from the diffraction grating patterns 13b1 and 13b3. The distance between the light transmitting portions 160a and 160b is determined by the pitch of the diffraction grating patterns 13b1 and 13b3. The direction and angle of the diffracted light incident on the reticle pattern are determined by the position of the diffracted light on the spatial filter 16, that is, the positions of the light transmitting portions 160a and 160c.

【００４２】同様に、光透過部１６０ｂ、１６０ｄは回
折格子状パターン１３ｂ２、１３ｂ４から生じる回折光
を透過するものであり、回折格子状パターン１３ｂ２、
１３ｂ４のピッチにより決まる空間フィルター１６上で
の回折光位置によりレチクルパターン２８に入射する光
束の方向、角度が決定する。又、回折格子状パターン１
３の形状は図２、図４に示すようなラインアンドスペー
スに限らず、図６に示すような市松格子状パターン１３
ｃであってもよい。ピッチの配列方向はレチクルパター
ンの配列方向に合わせておくことが望ましい。レチクル
上の周期パターン部分がｘ、ｙの両方向に並んでいる場
合は図６に示すように市松格子状パターン１３ｃのピッ
チをｘ、ｙ方向に配列するようにすればよい。そのデュ
ーティは１：１に限るものではない。図７は図６のごと
き市松格子状パターン１３ｃに対する空間フィルター１
６ｃを示したものであり、斜線部は遮光部を表し、白丸
は光透過部を表す。光透過部１６１ａと１６１ｂ，１６
１ｄと１６１ｃの間隔は図６に示す回折格子状パターン
１３ｃのｘ方向のピッチによって決まり、光透過部１６
１ａと１６１ｄ、１６１ｂと１６１ｃの間隔は図６に示
す回折格子状パターン１３ｃのｙ方向のピッチによって
決まる。レチクルパターン２８がｘ、ｙ２方向に周期構
造を持つ場合、光透過部１６１ａ、１６１ｄを透過した
照明光がｘ方向に周期構造を持つレチクルパターン２８
に入射したことにより発生する＋１次回折光は投影光学
系の瞳面において、それぞれ光透過部１６１ｂ、１６１
ｃを透過した照明光の０次回折光とほぼ同じ位置を通
り、逆に光透過部１６１ｂ、１６１ｃを透過した照明光
がｘ方向に周期構造を持ったレチクルパターン２８に入
射したことにより発生する−１次回折光は投影光学系の
瞳面で、それぞれ光透過部１６１ａ、１６１ｄを透過し
た照明光の０次回折光とほぼ同じ位置を通る。光軸から
各光透過部１６１ａ、１６１ｂ、１６１ｃ、１６１ｄま
での距離はみな等しく設定してあるので、この場合にも
各０次回折光と各＋１次回折光或いは−１次回折光とは
投影光学系の瞳面で光軸からの距離がほぼ等しい位置を
通る。また、光透過部１６１ａ〜１６１ｄを通る４つの
光束による照明光がレチクルパターン２８に入射するこ
とにより発生する＋１次または−１次のどちらか一方の
１次回折光と０次回折光の組み合わせは全てウェハ３０
に達するので前述の如くコントラストがほぼ９０％の像
が形成される。さらに、各０次回折光と１次回折光は、
投影光学系の瞳面で光軸からほぼ等距離となる位置を通
る為焦点深度も深いものとなる。Similarly, the light transmitting portions 160b and 160d transmit the diffracted light generated from the diffraction grating patterns 13b2 and 13b4.
The direction and angle of the light beam incident on the reticle pattern 28 are determined by the position of the diffracted light on the spatial filter 16 determined by the pitch of 13b4. Diffraction grating pattern 1
The shape of 3 is not limited to the line and space as shown in FIGS. 2 and 4, and the checkerboard pattern 13 as shown in FIG.
It may be c. It is desirable that the pitch arrangement direction is matched with the reticle pattern arrangement direction. When the periodic pattern portions on the reticle are arranged in both the x and y directions, the pitch of the checkerboard lattice pattern 13c may be arranged in the x and y directions as shown in FIG. The duty is not limited to 1: 1. FIG. 7 shows a spatial filter 1 for a checkered grid pattern 13c as shown in FIG.
6c, a hatched portion indicates a light shielding portion, and a white circle indicates a light transmitting portion. Light transmitting parts 161a and 161b, 16
The interval between 1d and 161c is determined by the pitch in the x direction of the diffraction grating pattern 13c shown in FIG.
The intervals between 1a and 161d and between 161b and 161c are determined by the pitch in the y direction of the diffraction grating pattern 13c shown in FIG. When the reticle pattern 28 has a periodic structure in the x and y2 directions, the illuminating light transmitted through the light transmitting portions 161a and 161d has a periodic structure in the x direction.
The + 1st-order diffracted light generated due to the light incident on the pupil plane of the projection optical system respectively has the light transmitting portions 161b and 161b.
This is caused by the fact that the illumination light passing through substantially the same position as the 0th-order diffracted light of the illumination light transmitted through the light transmission portion 161b and the light transmission portions 161b and 161c enters the reticle pattern 28 having a periodic structure in the x direction. The first-order diffracted light passes on the pupil plane of the projection optical system at substantially the same position as the zero-order diffracted light of the illumination light transmitted through the light transmitting portions 161a and 161d. Since the distances from the optical axis to the respective light transmitting portions 161a, 161b, 161c, 161d are all set to be equal, in this case also, each 0th-order diffracted light and each + 1st-order diffracted light or -1st-order diffracted light are converted by the projection optical system. It passes through a position on the pupil plane where the distance from the optical axis is approximately equal. The combination of either the + 1st-order or the -1st-order first-order diffracted light and the 0th-order diffracted light generated by the illumination light of the four light beams passing through the light transmitting portions 161a to 161d incident on the reticle pattern 28 is a wafer. 30
, An image having a contrast of about 90% is formed as described above. Further, each of the 0th-order diffracted light and the 1st-order diffracted light is
Since the light passes through a position on the pupil plane of the projection optical system which is almost equidistant from the optical axis, the depth of focus becomes deep.

【００４３】以上、ｘ方向に周期性を持つパターンの場
合について説明したが、ｙ方向に周期性を持つパターン
であってもよい。格子の方向はこれに限るものではなく
レチクルパターンに応じて、例えば斜め方向であっても
よい。また、図２のような繰り返し回折格子状パターン
１３ａが形成された光透過性基板２枚をパターン面が互
いに向かい合うように配置し、照明光学系の光軸を中心
として２枚の平板を相対的に回転し、夫々のパターンの
相対位置を調整して任意のパターンとしてもよい。さら
に、他の任意の形状の繰り返しパターンであってもよ
い。又回折格子状パターン１３は直線状のパターンのみ
でなく周期構造を持ったパターン、例えば同心円状の格
子パターン（フレネルゾーンプレート等）や同心状の楕
円状のパターンでもよい。Although the case of the pattern having the periodicity in the x direction has been described above, the pattern may have the periodicity in the y direction. The direction of the grating is not limited to this, and may be, for example, an oblique direction according to the reticle pattern. Further, two light-transmitting substrates on which the repetitive diffraction grating pattern 13a as shown in FIG. 2 is formed are arranged so that the pattern surfaces face each other, and the two flat plates are relatively positioned around the optical axis of the illumination optical system. , And the relative position of each pattern may be adjusted to an arbitrary pattern. Furthermore, a repetition pattern of another arbitrary shape may be used. The diffraction grating pattern 13 may be not only a linear pattern but also a pattern having a periodic structure, for example, a concentric lattice pattern (such as a Fresnel zone plate) or a concentric elliptical pattern.

【００４４】又、液晶等を使ってｘ、ｙ２方向について
任意の明暗部を持つパターンを作り出すようにしてもよ
い。これらの場合にも回折光の位置をもとに透過部を決
定した空間フィルター１６を使用すればよい。又、回折
格子状パターン１３の遮光面をＳｉＯ2等の誘電体薄膜
で形成された位相反転透過部（位相シフター部）で作成
してもよい。このように位相シフター部でパターンを構
成すると、不要な回折光の発生を抑えることができ、光
量の損失が少なくなる。又、図３に示すパターン１３ａ
の遮光面を位相シフターとした場合、０次回折光をカッ
トするための空間フィルター１６は設けなくともよい。Also, a pattern having an arbitrary bright and dark portion in the x and y2 directions may be created by using a liquid crystal or the like. In these cases, the spatial filter 16 whose transmission portion is determined based on the position of the diffracted light may be used. Further, the light-shielding surface of the diffraction grating pattern 13 may be formed by a phase inversion transmission portion (phase shifter portion) formed of a dielectric thin film such as SiO 2 . When the pattern is formed by the phase shifter as described above, generation of unnecessary diffracted light can be suppressed, and loss of light amount is reduced. The pattern 13a shown in FIG.
When the light-shielding surface is a phase shifter, the spatial filter 16 for cutting the zero-order diffracted light need not be provided.

【００４５】次に像劣化手段の変形例として、空間フィ
ルター１６の開口部（白丸部）に光学素子を設けて回折
格子状パターン１３の像を劣化させる方法を説明する。
空間フィルター１６の各開口部にそれぞれ厚さ又は屈折
率の異なる透過性平板を付着させておくとそれぞれの開
口部を透過する光は、前記透過性平板の厚さ×屈折率だ
け長い光路長を通ることになる。各開口を通った光束の
光路長の差が照明光のコヒーレント長より長ければ各開
口部を透過した光同士はレチクルパターン面において互
いに干渉し合わない、つまり、回折格子状パターンの像
を生じないことになる。例えば照明光が水銀ランプのｉ
線（波長＝０．３６５μｍ、波長幅＝０．００５μｍ）
であると照明光のコヒーレント長はほぼ２７μｍであ
る。前述の光透過性平板として屈折率１．５のガラスを
使用すると、空気の屈折率を１として各開口部に付着さ
れた平板の厚さの差（Δｔ）は、 Δｔ×（１．５−１）≧２７μｍ であればよく、Δｔ≧５４μｍの厚さの差を有していれ
ばよい。Next, as a modified example of the image deterioration means, a method of providing an optical element in the opening (open circle) of the spatial filter 16 to deteriorate the image of the diffraction grating pattern 13 will be described.
If a transparent flat plate having a different thickness or refractive index is attached to each opening of the spatial filter 16, light transmitted through each opening has an optical path length longer by the thickness of the transparent flat plate times the refractive index. I will pass. If the difference in the optical path lengths of the light beams passing through the openings is longer than the coherent length of the illumination light, the lights transmitted through the openings do not interfere with each other on the reticle pattern surface, that is, do not produce an image of a diffraction grating pattern. Will be. For example, if the illumination light is a mercury lamp i
Line (wavelength = 0.365 μm, wavelength width = 0.005 μm)
, The coherent length of the illumination light is approximately 27 μm. When glass having a refractive index of 1.5 is used as the light-transmitting flat plate, the difference (Δt) between the thicknesses of the flat plates attached to the openings with the refractive index of air being 1 is Δt × (1.5− 1) It suffices if ≧ 27 μm, and it is only necessary to have a thickness difference Δt ≧ 54 μm.

【００４６】従って、例えば図３に示すような空間フィ
ルター各開口部に例えば屈折率１．５で厚さがそれぞれ
１０００μｍ，１０６０μｍ（厚さの差が６０μｍ）の
ガラスを付着すると、レチクルパターン面上での干渉縞
すなわち回折格子状パターンの像は消失（劣化）するこ
とになる。この様に空間フィルター１６の各開口部に厚
さ又は屈折率の異なる光透過性平板を付着した場合、前
記回折格子状パターン１３、前記光学部材或いは前記光
散乱部材１７の振動、移動或いは回転等は行わなくても
よい。Therefore, for example, when glass having a refractive index of 1.5 and a thickness of 1000 μm and a thickness of 1060 μm (a thickness difference of 60 μm) is attached to each opening of the spatial filter as shown in FIG. , Ie, the image of the diffraction grating pattern disappears (degrades). When light-transmitting flat plates having different thicknesses or refractive indices are attached to the respective openings of the spatial filter 16 as described above, vibration, movement, rotation, or the like of the diffraction grating pattern 13, the optical member, or the light scattering member 17 is performed. Need not be performed.

【００４７】照明光の可干渉距離が長い場合、例えばレ
ーザ光源を使用する場合には、空間フィルター１６の開
口部のうちの片方に水晶等の旋光素子を付着させて、透
過光の偏光方向をほぼ９０°回転させるとよい。残りの
開口部には上述旋光素子とほぼ光路長の等しいガラス等
の透過性平板を付着させておく。この様な空間フィルタ
ーを用いるとレチクルパターン面に照射される光束のう
ちほぼ半数は偏光方向が互いに直交する（又は逆回りの
円偏向となる）ので干渉縞すなわち前記回折格子状パタ
ーンの像は劣化する。また、前記回折格子状パターン１
３を前記レチクルパターン２８との共役位置より僅かに
光軸方向にずらした位置とすることによってレチクルパ
ターン２８上に投影される回折格子状パターン１３の像
を劣化（デフォーカス）させてもよい。When the coherence length of the illumination light is long, for example, when a laser light source is used, an optical rotation element such as quartz is attached to one of the openings of the spatial filter 16 to change the polarization direction of the transmitted light. It is good to rotate it by approximately 90 °. A transparent flat plate made of glass or the like having substantially the same optical path length as the optical rotation element is attached to the remaining openings. When such a spatial filter is used, almost half of the luminous flux irradiated on the reticle pattern surface has polarization directions orthogonal to each other (or becomes circularly polarized in opposite directions), so that interference fringes, that is, the image of the diffraction grating pattern is deteriorated. I do. The diffraction grating pattern 1
The image of the diffraction grating pattern 13 projected on the reticle pattern 28 may be degraded (defocused) by setting 3 to a position slightly shifted in the optical axis direction from the conjugate position with the reticle pattern 28.

【００４８】更に、光束変換部材として周期構造を持っ
たパターンを含む光透過性平板１２の代わりに図８に示
すようにウォラストンプリズム３３等の光学素子でレチ
クルパターン２８に入射する２光束に変換してもよい。
尚、本実施例においては光源を水銀ランプ１としたが、
他の輝線ランプあるいはレーザ光源であっても良い。Further, instead of the light-transmitting flat plate 12 including a pattern having a periodic structure as a light beam converting member, as shown in FIG. 8, an optical element such as a Wollaston prism 33 converts the light beam into two light beams incident on the reticle pattern 28. May be.
In this embodiment, the light source is the mercury lamp 1,
Other bright line lamps or laser light sources may be used.

【００４９】又、光透過性平板１２の代わりに周期構造
を持つパターンを含む反射型平板を用いてもよい。Further, instead of the light transmitting flat plate 12, a reflective flat plate including a pattern having a periodic structure may be used.

【００５０】[0050]

【発明の効果】以上のように本発明によれば、照明光学
系の瞳面上で任意の照明光量分布を実現することがで
き、レチクルパターンに応じた光束をレチクルパターン
に入射させることができる。このため、投影光学系に入
射する光束の角度を調整可能とし、高い解像度をもち、
かつ、光量損失のない投影型露光装置を得ることができ
る。また、レチクル面上に生じる光束変換部材の像は像
劣化手段により劣化され、或いは時間的に平均化されて
劣化し、レチクルパターン面での照度均一化の悪化を防
止できる。このため、使用する光束変換部材の製造上の
欠陥に影響されず光束変換部材の製造コストを大幅に低
減できる。さらに、解像度向上度は位相シフターに匹敵
するものがありながら、従来のフォトマスクがそのまま
使用でき、従来のフォトマスク検査技術もそのまま踏襲
することができる。As described above, according to the present invention, an arbitrary illumination light amount distribution can be realized on the pupil plane of the illumination optical system, and a light beam corresponding to the reticle pattern can be incident on the reticle pattern. . For this reason, the angle of the light beam incident on the projection optical system can be adjusted, and has a high resolution.
In addition, it is possible to obtain a projection type exposure apparatus without loss of light quantity. Further, the image of the light beam converting member generated on the reticle surface is deteriorated by the image deterioration means or is averaged and deteriorated over time, thereby preventing deterioration of uniformity of illuminance on the reticle pattern surface. For this reason, the manufacturing cost of the light beam conversion member can be significantly reduced without being affected by manufacturing defects of the light beam conversion member used. Further, while the degree of resolution improvement is comparable to that of a phase shifter, a conventional photomask can be used as it is, and a conventional photomask inspection technique can be followed as it is.

【００５１】更に、位相シフターを採用すると、焦点深
度が増大する効果も得られるが、本発明においてもデフ
ォーカスによる波面収差の影響を受けにくく、従って、
深い焦点深度が得られる。Further, when the phase shifter is employed, the effect of increasing the depth of focus can be obtained. However, the present invention is also less susceptible to the wavefront aberration due to defocusing.
A deep depth of focus can be obtained.

【図面の簡単な説明】[Brief description of the drawings]

【図１】本発明の一実施例による全体構成を示す図。FIG. 1 is a diagram showing an overall configuration according to an embodiment of the present invention.

【図２】周期構造のパターンを含む光透過性基板（光束
変換部材）を示す図。FIG. 2 is a view showing a light-transmitting substrate (light flux conversion member) including a pattern of a periodic structure.

【図３】図２のようなパターンに対応する空間フィルタ
ーを示す図。FIG. 3 is a diagram showing a spatial filter corresponding to the pattern as shown in FIG. 2;

【図４】周期構造パターンの変形例を示す図。FIG. 4 is a diagram showing a modification of the periodic structure pattern.

【図５】図４のようなパターンに対応する空間フィルタ
ーを示す図。FIG. 5 is a view showing a spatial filter corresponding to the pattern as shown in FIG. 4;

【図６】周期構造パターンの変形例を示す図。FIG. 6 is a diagram showing a modification of the periodic structure pattern.

【図７】図６のようなパターンに対応する空間フィルタ
ーを示す図。FIG. 7 is a diagram showing a spatial filter corresponding to the pattern shown in FIG. 6;

【図８】プリズムを使った光束変換部材の変形例を示す
図。FIG. 8 is a diagram showing a modified example of a light beam conversion member using a prism.

【図９】本発明の原理説明図。FIG. 9 is a diagram illustrating the principle of the present invention.

【図１０】従来の装置を示す図。FIG. 10 is a diagram showing a conventional device.

【符号の説明】[Explanation of symbols]

１…光源、１２…光透過性平板、１３…回折格子状パタ
ーン、１６…空間フィルター、１７，１８，２１，２
３，２５…像劣化手段、２７…レチクル、２８…レチク
ルパターン、２９…投影光学系、３０…ウェハ、３３…
ウォラストンプリズムDESCRIPTION OF SYMBOLS 1 ... Light source, 12 ... Light transmissive flat plate, 13 ... Diffraction grating pattern, 16 ... Spatial filter, 17,18,21,2
3, 25 image degrading means, 27 reticle, 28 reticle pattern, 29 projection optical system, 30 wafer, 33
Wollaston prism

Claims (32)

(57)【特許請求の範囲】(57) [Claims] 【請求項１】マスクに照明光を照射する照明光学系と、
前記照明光を基板上に投射する投影光学系とを備えた露
光装置において、 前記照明光学系の瞳面上での前記照明光の光量分布を前
記照明光学系の光軸から前記マスクのパターンの配列方
向に離れるとともに、前記パターンの微細度に応じて前
記光軸との距離がほぼ等しく定められる複数の領域で高
めるために、前記照明光を入射して前記光軸と異なる方
向に回折光を発生する回折光学素子を備え、前記照明光
学系内で前記パターンとほぼ共役な位置又はその近傍に
前記回折光学素子を配置したことを特徴とする露光装
置。An illumination optical system for irradiating illumination light to a mask,
In exposure <br/> optical apparatus having a projection optical system for projecting the illuminating light on the substrate, before the light intensity distribution of the illumination light on the pupil plane of the illumination optical system
How to arrange the pattern of the mask from the optical axis of the illumination optical system
Away from the front and depending on the fineness of the pattern,
High in multiple areas where the distance from the optical axis is almost equal
The illumination light to make it different from the optical axis
A diffractive optical element for generating diffracted light in the
At a position almost conjugate with the pattern in the academic system or in the vicinity thereof
An exposure apparatus comprising the diffractive optical element . 【請求項２】前記回折光学素子は、前記照明光学系の光
軸に沿って進む回折光の光量をほぼ零にすることを特徴
とする請求項１に記載の露光装置。2. An exposure apparatus according to claim 1 , wherein said diffractive optical element makes the amount of diffracted light traveling along the optical axis of said illumination optical system substantially zero. 【請求項３】前記回折光学素子は位相反転透過部を有す
ることを特徴とする請求項１又は２に記載の露光装置。3. An exposure apparatus according to claim 1, wherein said diffractive optical element has a phase inversion transmitting section . 【請求項４】前記回折光学素子は０次回折光の発生が抑
制される位相型であることを特徴とする請求項１又は２
に記載の露光装置。4. The diffractive optical element suppresses generation of zero-order diffracted light.
3. The method according to claim 1, wherein the phase type is controlled.
3. The exposure apparatus according to claim 1. 【請求項５】前記複数の領域はその数が２ｎ個（ｎは自
然数）であることを特徴とする請求項１〜４のいずれか
一項に記載の露光装置。5. The number of the plurality of regions is 2n (where n is
Natural number) exposure apparatus according to any one of claims 1 to 4, characterized in der Rukoto. 【請求項６】前記複数の領域は前記照明光学系の光軸に
関してほぼ対称に配置されることを特徴とする請求項１
〜５のいずれか一項に記載の露光装置。 6. The illumination optical system according to claim 1, wherein the plurality of regions are located on an optical axis of the illumination optical system.
Claim 1, wherein Rukoto arranged substantially symmetrically regarding
The exposure apparatus according to any one of claims 1 to 5. 【請求項７】前記パターンが第１及び第２方向にそれぞ
れ周期構造を有するとき、前記各領域から射出される光
束が前記第１及び第２方向の両方と交差する方向から前
記マスクに入射するように、前記各領域の位置を規定す
ることを特徴とする請求項１〜６のいずれか一項に記載
の露光装置。7. The pattern according to claim 1, wherein said pattern is in a first direction and a second direction.
Light having a periodic structure
Forward from the direction in which the bundle intersects both said first and second directions
The exposure apparatus according to any one of claims 1 to 6 , wherein a position of each of the regions is defined so as to be incident on the mask . 【請求項８】前記パターンが第１及び第２方向にそれぞ
れ周期構造を有するとき、前記複数の領域のうち第１及
び第２領域を前記第１方向に沿って配置し、前記第１領
域と第３領域とを前記第２方向に沿って配置し、前記第
３領域と第４領域とを前記第１方向に沿って配置し、か
つ前記第２及び第４領域を前記第２方向に沿って配置す
ることを特徴とする請求項１〜７のいずれか一項に記載
の露光装置。8. The method according to claim 1, wherein said pattern is formed in first and second directions.
When having a periodic structure, the first and
And a second region are arranged along the first direction, and the first region
Region and a third region are arranged along the second direction, and the
Three regions and a fourth region are arranged along the first direction;
The second and fourth regions are arranged along the second direction.
The exposure apparatus according to any one of claims 1 to 7, wherein: 【請求項９】前記照明光学系の瞳面上で前記照明光の光
量重心を光軸とほぼ一致させることを特徴とする請求項
１〜８のいずれか一項に記載の露光装置。9. The light of the illumination light on a pupil plane of the illumination optical system.
The mass center of gravity substantially coincides with the optical axis.
The exposure apparatus according to any one of claims 1 to 8. 【請求項１０】前記各領域から射出される光束の前記マ
スクへの入射角をψ、前記光束の照射によって前記パタ
ーンから発生する同次数の２つの回折光の回折角をθ、
前記投影光学系の前記マスク側の開口数をＮＡRとする
と、前記２つの回折光の一方でｓｉｎ(θ−ψ)＝ＮＡR
なる関係が満たされるときを前記投影光学系の解像限界
とすることを特徴とする請求項１〜９のいずれか一項に
記載の露光装置。10. An angle of incidence of a light beam emitted from each of the regions on the mask, a diffraction angle of two diffracted lights of the same order generated from the pattern by irradiation of the light beam, θ,
And the numerical aperture of the mask side of the projection optical system is NA R, while at sin (θ-ψ) of the two diffracted lights = NA R
When the following relationship is satisfied , the resolution limit of the projection optical system
The exposure apparatus according to any one of claim 1 to 9, characterized in that a. 【請求項１１】前記関係を満たす前記一方の回折光は、
前記投影光学系の光軸に関して前記パターンから発生す
る０次回折光とほぼ対称になることを特徴とする請求項
１０に記載の露光装置。11. The one diffracted light satisfying the above relationship,
An apparatus according to claim 1 0, characterized in that is substantially symmetrical to the zero-order diffracted light generated from the pattern with respect to the optical axis of the projection optical system. 【請求項１２】前記照明光の波長をλ、前記照明光の前
記マスクへの入射角をψ、前記投影光学系の前記マスク
側の開口数をＮＡ R として、前記基板上に転写可能なパ
ターンの最小ピッチがλ／(ＮＡ R ＋ｓｉｎψ)であるこ
とを特徴とする請求項１〜１１のいずれか一項に記載の
露光装置。12. The wavelength of the illumination light is λ, and the wavelength of the illumination light is
The incident angle on the mask is ψ, and the mask of the projection optical system is
The numerical aperture of the side as NA R, transferable path on the substrate
The minimum pitch of the turn is λ / (NA R + sinψ)
The exposure apparatus according to claim 1, wherein: 【請求項１３】前記照明光の波長をλ、前記投影光学系
の前記マスク側の開口数をＮＡ R として、前記パターン
はピッチがλ／ＮＡ R よりも小さい周期構造を有するこ
とを特徴とする請求項１〜１２のいずれか一項に記載の
露光装置。13. The projection optical system, wherein a wavelength of the illumination light is λ,
The numerical aperture as NA R of the mask side, the pattern
Has a periodic structure with a pitch smaller than λ / NA R
The exposure apparatus according to claim 1, wherein: 【請求項１４】前記複数の領域の１つから射出される第
１光束の照射によって前記パターンから発生する第１回
折光と、前記１つの領域と異なる別の領域から射出され
る第２光束の照射によって前記パターンから発生する前
記第１回折光と次数が異なる第２回折光とは、前記投影
光学系の瞳面上でその光軸から偏心したほぼ同一位置を
通ることを特徴とする請求項１〜１３のいずれか一項に
記載の露光装置。14. A first diffracted light generated from the pattern by irradiation of a first light beam emitted from one of the plurality of areas, and emitted from another area different from the one area.
That the second light flux the first diffractive light and orders generated from the pattern is different second diffraction light by the irradiation of the through substantially the same position deviated from the optical axis on the pupil plane of the projection optical system the exposure apparatus according to any one of claims 1 to 1 3, characterized. 【請求項１５】前記第１光束の照射によって前記パター
ンから発生する前記第１回折光と次数が異なる第３回折
光と、前記第２光束の照射によって前記パターンから発
生する前記第２回折光と次数が異なる第４回折光とは、
前記投影光学系の瞳面上でその光軸から偏心したほぼ同
一位置を通り、かつ前記投影光学系の光軸との距離が前
記第１及び第２回折光とほぼ等しいことを特徴とする請
求項１４に記載の露光装置。15. A third diffracted light having a different order from the first diffracted light generated from the pattern by the irradiation of the first light flux, and a second diffracted light generated from the pattern by the irradiation of the second light flux. The fourth diffracted light having a different order is
The optical system according to claim 1, wherein the light passes through substantially the same position decentered from the optical axis on the pupil plane of the projection optical system, and has a distance from the optical axis of the projection optical system substantially equal to the first and second diffracted lights. An apparatus according to claim 1 4. 【請求項１６】前記各領域から射出される光束の開口数
を０．２〜０．３程度に定めることを特徴とする請求項
１〜１５のいずれか一項に記載の露光装置。16. The exposure apparatus according to any one of claims 1 to 1 5 to the numerical aperture of the light beam emitted from the respective regions, characterized in that provided for in the order of 0.2 to 0.3. 【請求項１７】マスクに照明光を照射するとともに、投
影光学系を介して前記照明光で基板を露光する方法にお
いて、 前記照明光学系の瞳面上での前記照明光の光量分布を前
記照明光学系の光軸から前記マスクのパターンの配列方
向に離れるとともに、前記パターンの微細度に応じて前
記光軸との距離がほぼ等しく定められる複数の領域で高
めるために、前記照明光学系内で前記パターンとほぼ共
役な位置又はその近傍に配置される回折光学素子で前記
光軸と異なる方向に回折光を発生することを特徴とする
露光方法。17. A method of irradiating a mask with illumination light and exposing a substrate with the illumination light via a projection optical system, wherein a light amount distribution of the illumination light on a pupil plane of the illumination optical system is previously determined.
How to arrange the pattern of the mask from the optical axis of the illumination optical system
Away from the front and depending on the fineness of the pattern,
High in multiple areas where the distance from the optical axis is almost equal
In the illumination optical system,
The diffractive optical element arranged at or near a useful position
An exposure method comprising generating diffracted light in a direction different from the optical axis . 【請求項１８】前記照明光学系の光軸に沿って進む回折
光の光量をほぼ零にすることを特徴とする請求項１７に
記載の露光方法。18. Diffraction traveling along an optical axis of the illumination optical system.
The exposure method according to claim 17, characterized in that the amount of light to substantially zero. 【請求項１９】前記回折光学素子は０次回折光の発生が
抑制される位相型であることを特徴とする請求項１７又
は１８に記載の露光方法。19. The diffractive optical element generates zero-order diffracted light.
18. A phase type which is suppressed.
19. The exposure method according to 18 . 【請求項２０】前記複数の領域はその数が２ｎ個（ｎは
自然数）であることを特徴とする請求項１７〜１９のい
ずれか一項に記載の露光方法。20. The number of the plurality of regions is 2n (n is
20. A method according to claim 17, wherein
The exposure method according to any one of the preceding claims . 【請求項２１】前記複数の領域は前記照明光学系の光軸
に関してほぼ対称に配置されることを特徴とする請求項
１７〜２０のいずれか一項に記載の露光方法。21. The plurality of areas are optical axes of the illumination optical system.
Claims characterized by being arranged substantially symmetrically with respect to
21. The exposure method according to any one of 17 to 20 . 【請求項２２】前記パターンが第１及び第２方向にそれ
ぞれ周期構造を有するとき、前記各領域から射出される
光束が前記第１及び第２方向の両方と交差する方向から
前記マスクに入射するように、前記各領域の位置を規定
することを特徴とする請求項１７〜２１のいずれか一項
に記載の露光方法。22. The method according to claim 19, wherein the pattern is displaced in first and second directions.
When each has a periodic structure, it is emitted from each of the regions.
From the direction in which the light beam intersects both the first and second directions
Define the position of each area so as to be incident on the mask
The exposure method according to any one of claims 17 to 21, wherein the exposure is performed. 【請求項２３】前記パターンが第１及び第２方向にそれ
ぞれ周期構造を有するとき、前記複数の領域のうち第１
及び第２領域を前記第１方向に沿って配置し、前記第１
領域と第３領域とを前記第２方向に沿って配置し、前記
第３領域と第４領域とを前記第１方向に沿って配置し、
かつ前記第２及び第４領域を前記第２方向に沿って配置
することを特徴とする請求項１７〜２２のいずれか一項
に記載の露光方法。23. The pattern according to claim 19, wherein the pattern is deflected in first and second directions.
When each of the plurality of regions has a periodic structure,
And the second region is arranged along the first direction, and the first region
Arranging a region and a third region along the second direction,
A third region and a fourth region are arranged along the first direction;
And arranging the second and fourth regions along the second direction.
The exposure method according to any one of claims 17 to 22, wherein the exposure is performed. 【請求項２４】前記照明光学系の瞳面上で前記照明光の
光量重心を光軸とほぼ一致させることを特徴とする請求
項１７〜２３のいずれか一項に記載の露光方法。24. An illumination optical system comprising:
The exposure method according to any one of claims 17 to 23, wherein the center of gravity of the light amount is made substantially coincident with the optical axis . 【請求項２５】前記各領域から射出される光束の前記マ
スクへの入射角をψ、前記光束の照射によって前記パタ
ーンから発生する同次数の２つの回折光の回折角をθ、
前記投影光学系の前記マスク側の開口数をＮＡRとする
と、前記２つの回折光の一方でｓｉｎ(θ−ψ)＝ＮＡR
なる関係が満たされるときを前記投影光学系の解像限界
とすることを特徴とする請求項１７〜２４のいずれか一
項に記載の露光方法。25. An incident angle of a light beam emitted from each of the regions to the mask, and a diffraction angle of two diffraction lights of the same order generated from the pattern by irradiation of the light beam, θ.
And the numerical aperture of the mask side of the projection optical system is NA R, while at sin (θ-ψ) of the two diffracted lights = NA R
When the following relationship is satisfied , the resolution limit of the projection optical system
The exposure method according to any one of claims 17-24, characterized in that a. 【請求項２６】前記関係を満たす前記一方の回折光は、
前記投影光学系の光軸に関して前記パターンから発生す
る０次回折光とほぼ対称になることを特徴とする請求項
２５に記載の露光方法。26. The one diffracted light satisfying the above relationship,
26. The exposure method according to claim 25 , wherein the light is substantially symmetric with respect to an optical axis of the projection optical system with respect to a zero-order diffracted light generated from the pattern. 【請求項２７】前記照明光の波長をλ、前記照明光の前
記マスクへの入射角をψ、前記投影光学系の前記マスク
側の開口数をＮＡ R として、前記基板上に転写可能なパ
ターンの最小ピッチがλ／(ＮＡ R ＋ｓｉｎψ)であるこ
とを特徴とする請求項１７〜２６のいずれか一項に記載
の露光方法。27. The wavelength of the illumination light is λ, and the wavelength of the illumination light is
The incident angle on the mask is ψ, and the mask of the projection optical system is
The numerical aperture of the side as NA R, transferable path on the substrate
The minimum pitch of the turn is λ / (NA R + sinψ)
The exposure method according to any one of claims 17 to 26, wherein: 【請求項２８】前記照明光の波長をλ、前記投影光学系
の前記マスク側の開口数をＮＡ R として、前記パターン
はピッチがλ／ＮＡ R よりも小さい周期構造を有するこ
とを特徴とする請求項１７〜２７のいずれか一項に記載
の露光方法。28. The projection optical system, wherein the wavelength of the illumination light is λ.
The numerical aperture as NA R of the mask side, the pattern
The exposure method according to any one of claims 17 to 27, characterized in the this <br/> having a period smaller structure than pitch lambda / NA R is. 【請求項２９】前記複数の領域の１つから射出される第
１光束の照射によって前記パターンから発生する第１回
折光と、前記１つの領域と異なる別の領域から射出され
る第２光束の照射によって前記パターンから発生する前
記第１回折光と次数が異なる第２回折光とは、前記投影
光学系の瞳面上でその光軸から偏心したほぼ同一位置を
通ることを特徴とする請求項１７〜２８のいずれか一項
に記載の露光方法。29. A first diffracted light generated from the pattern by irradiation of a first light beam emitted from one of the plurality of areas, and emitted from another area different from the one area.
That the second light flux the first diffractive light and orders generated from the pattern is different second diffraction light by the irradiation of the through substantially the same position deviated from the optical axis on the pupil plane of the projection optical system The exposure method according to any one of claims 17 to 28 , characterized in that: 【請求項３０】前記第１光束の照射によって前記パター
ンから発生する前記第１回折光と次数が異なる第３回折
光と、前記第２光束の照射によって前記パターンから発
生する前記第２回折光と次数が異なる第４回折光とは、
前記投影光学系の瞳面上でその光軸から偏心したほぼ同
一位置を通り、かつ前記投影光学系の光軸との距離が前
記第１及び第２回折光とほぼ等しいことを特徴とする請
求項２９に記載の露光方法。30. A third diffracted light having a different order from the first diffracted light generated from the pattern by the irradiation of the first light beam, and a second diffracted light generated from the pattern by the irradiation of the second light beam. The fourth diffracted light having a different order is
The optical system according to claim 1, wherein the light passes through substantially the same position decentered from the optical axis on the pupil plane of the projection optical system, and has a distance from the optical axis of the projection optical system substantially equal to the first and second diffracted lights. Item 30. An exposure method according to Item 29 . 【請求項３１】前記各領域から射出される光束の開口数
を０．２〜０．３程度に定めることを特徴とする請求項
１７〜３０のいずれか一項に記載の露光方法。31. The numerical aperture of a light beam emitted from each of the regions is set to about 0.2 to 0.3.
The exposure method according to any one of claims 17 to 30 . 【請求項３２】請求項１７〜３１のいずれか一項に記載
された露光方法を用いて、デバイスパターンをウエハ上
に転写する工程を含むことを特徴とする半導体素子の製
造方法。32. A method of manufacturing a semiconductor device, comprising a step of transferring a device pattern onto a wafer by using the exposure method according to claim 17 .
JP20679499A 1999-07-21 1999-07-21 Exposure apparatus and method, and method of manufacturing semiconductor element Expired - Lifetime JP3244076B2 (en)

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