JPS6314112A - Projection optical system for fine pattern - Google Patents
Projection optical system for fine patternInfo
- Publication number
- JPS6314112A JPS6314112A JP61159050A JP15905086A JPS6314112A JP S6314112 A JPS6314112 A JP S6314112A JP 61159050 A JP61159050 A JP 61159050A JP 15905086 A JP15905086 A JP 15905086A JP S6314112 A JPS6314112 A JP S6314112A
- Authority
- JP
- Japan
- Prior art keywords
- optical system
- aperture
- center
- phase correction
- mirror member
- 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.)
- Pending
Links
- 230000003287 optical effect Effects 0.000 title claims abstract description 71
- 238000005286 illumination Methods 0.000 claims abstract description 14
- 230000004907 flux Effects 0.000 claims abstract description 12
- 239000010453 quartz Substances 0.000 abstract description 3
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N silicon dioxide Inorganic materials O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 abstract description 3
- 230000004304 visual acuity Effects 0.000 abstract 1
- 230000001427 coherent effect Effects 0.000 description 7
- 238000002834 transmittance Methods 0.000 description 7
- 239000000463 material Substances 0.000 description 4
- 238000001228 spectrum Methods 0.000 description 4
- 230000004075 alteration Effects 0.000 description 3
- 239000013078 crystal Substances 0.000 description 3
- 238000004458 analytical method Methods 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 239000011521 glass Substances 0.000 description 2
- 230000031700 light absorption Effects 0.000 description 2
- 230000015572 biosynthetic process Effects 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 238000000034 method Methods 0.000 description 1
- 210000001747 pupil Anatomy 0.000 description 1
- 239000004065 semiconductor Substances 0.000 description 1
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
- G03F7/70225—Optical aspects of catadioptric systems, i.e. comprising reflective and refractive elements
-
- 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
- G03F7/70308—Optical correction elements, filters or phase plates for manipulating imaging light, e.g. intensity, wavelength, polarisation, phase or image shift
Landscapes
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Lenses (AREA)
- Projection-Type Copiers In General (AREA)
- Exposure And Positioning Against Photoresist Photosensitive Materials (AREA)
- Exposure Of Semiconductors, Excluding Electron Or Ion Beam Exposure (AREA)
Abstract
Description
【発明の詳細な説明】
産業上の利用分野
本発明は、半導体、ＬＳＩなどの微細なパターンを露光
するために用いる微細パターン投影光学系に関するもの
である。DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a fine pattern projection optical system used for exposing fine patterns of semiconductors, LSIs, etc.
従来の技術
従来の精密複写用投影光学系としては、例えば、特公昭
５５−１０８８３号公報に記載されているようにレンズ
のみによる屈析系から成るものが知られている。一方、
例えば特公昭２８−５７３５号公報に記載されているよ
うに反射系から成る反射顕微鏡用対物鏡が知られている
。2. Description of the Related Art As a conventional projection optical system for precision copying, there is known a system consisting of a refracting system using only lenses, as described in, for example, Japanese Patent Publication No. 10883/1983. on the other hand,
For example, as described in Japanese Patent Publication No. Sho 28-5735, an objective mirror for a reflection microscope comprising a reflection system is known.
以下、図面を参照しながら従来の投影光学系について説
明する。A conventional projection optical system will be described below with reference to the drawings.
第４図は従来の屈析系を用いた投影光学系の断面図であ
る。第４図に示すように多数枚のレンズＧが用いられ、
被投影パターン１０１はコヒーレントな準単色光による
平行光束ＩＬにより照明されている。本光学系は再回析
光学系（被投影物体の回析光が瞳面で一旦、回折次数毎
の輝点、Ｓ、。FIG. 4 is a sectional view of a projection optical system using a conventional refracting system. As shown in FIG. 4, a large number of lenses G are used,
The projected pattern 101 is illuminated by a parallel light flux IL of coherent quasi-monochromatic light. This optical system is a re-diffraction optical system (the diffracted light of the object to be projected is once on the pupil plane, a bright spot, S, for each diffraction order).
Ｓｏ、Ｓ、スペクトルとなり、再度、広がりを持つ光束
となり、レンズＧより出射し、像面にて０次回析光及び
±１次回折先の重なりとして像形成を行う光学系）とな
っており、垂直斜線を施した光束がＯ次回析光、右上り
の斜線を施した光束が＋１次回析光、左上りの斜線を施
した光束が一１次回析光である。回折角θは被投影物体
の空間周波数をＵ（パターンピッチの逆数）とし、光源
の波長をλとすると、
ス
Ｓｉｎθニー
という関係となる。It becomes a So, S spectrum, becomes a spread light beam again, exits from the lens G, and forms an image at the image plane as an overlap of the 0th-order diffraction light and the ±1st-order diffraction points). The vertically shaded light beam is the O-th order diffraction light, the light beam with the upper-right diagonal line is the +1st-order diffraction light, and the light flux with the upper-left diagonal line is the 11th-order diffraction light. The diffraction angle θ has the following relationship, where U is the spatial frequency of the object to be projected (the reciprocal of the pattern pitch) and λ is the wavelength of the light source.
被投影物体１０１から出た各回析光は絞りｓｐ上で輝点
スペクトルに分離し、後側のレンズ系を通過後、再び平
行光束となり像面１０２上で重なり、干渉縞により投影
パターンの形成を行う。Each diffracted light emitted from the projection object 101 is separated into a bright spot spectrum on the aperture sp, and after passing through the rear lens system, it becomes a parallel light beam again and overlaps on the image plane 102, forming a projection pattern by interference fringes. conduct.
第５図は従来の反射系を用いた反射顕微鏡用対物鏡の断
面図である。第５図に示すように被投影物体１０１から
出た光束が副鏡１０５、主鏡１０６の順に反射され、被
投影物体１０１と反対側の平面１０２上に縮小された像
ｌを形成するようになっている。FIG. 5 is a sectional view of an objective mirror for a reflection microscope using a conventional reflection system. As shown in FIG. 5, the light flux emitted from the projection object 101 is reflected by the secondary mirror 105 and the primary mirror 106 in this order, and forms a reduced image l on the plane 102 on the opposite side of the projection object 101. It has become.
発明が解決しようとする問題点
投影光学系の解像限界りは、レーリーの式を用いて表現
すると、
λ
Ｄ＝０．６１−
ＮＡ
但し、ＮＡ：光学系の像側の開口数、λ：使用波長で与
えられ、解像力向上のためには、使用波長λを小さくす
るか、光学系の開口数ＮＡを太きくすれば良いが、開口
数ＮＡの向上は、レンズの光学設計を著しく困難とする
ため、使用波長スを小さくする方向での対応が主流とな
りつつある。Problem to be Solved by the Invention The resolution limit of the projection optical system is expressed using Rayleigh's equation as follows: λ D = 0.61- NA where NA: numerical aperture on the image side of the optical system, λ: In order to improve the resolution, it is possible to reduce the wavelength λ used or increase the numerical aperture NA of the optical system, but improving the numerical aperture NA makes optical design of the lens extremely difficult. Therefore, the mainstream approach is to reduce the wavelength used.
第４図に示した従来の屈析光学系においては、使用波長
大を紫外域まで短くすると、透過率が極端に低下する。In the conventional dioptric optical system shown in FIG. 4, when the wavelength used is shortened to the ultraviolet region, the transmittance is extremely reduced.
例えば、レンズＧにショット社製のＵＢＫ７のように特
に紫外域の波長用に調質されたガラスを用いても、波長
が２８０ ｎｍでは透過率が２３％（ガラス厚５ｍｍの
場合）となる。For example, even if lens G is made of glass specially tempered for wavelengths in the ultraviolet region, such as UBK7 manufactured by Schott, the transmittance is 23% at a wavelength of 280 nm (when the glass thickness is 5 mm).
一方、光学結晶材の内、Ｔ ｉ Ｆ Ｃａ Ｆ ２
、Ｋｃ１合成δ晶のように２００ ｎｍ付近の波長にお
いても、約８０％の透過率が得られるものがあるが、一
般的に大型の結晶材の入手が困難であり、加工性が非常
に悪く、高精度の加工が難しい。また種類が限られるた
め、設計の自由度が小さくなり、紫外域、あるいは遠紫
外域の波長において、限られた枚数で透過率を確保しな
がら開口数ＮＡの大きな再回析光学系を実現しようとす
ると、十分な収差補正を行うことができず、屈析材料の
みにより光学系を構成するのは困難である。On the other hand, among optical crystal materials, T i F Ca F 2
, Kc1 synthetic δ crystals have a transmittance of about 80% even at wavelengths around 200 nm, but it is generally difficult to obtain large crystal materials, and processability is very poor. , difficult to process with high precision. In addition, since the types are limited, the degree of freedom in design is reduced, and it is necessary to realize a re-diffraction optical system with a large numerical aperture NA while ensuring transmittance with a limited number of lenses at wavelengths in the ultraviolet or deep ultraviolet range. If so, sufficient aberration correction cannot be performed, and it is difficult to construct an optical system using only refractive materials.
一方、第５図に示した従来の反射光学系においては、反
射鏡のみで構成されているため、使用波長に対する制約
はない。しかし、本光学系を再回析光学系として見た場
合、副鏡１０５によってＯ次回析光が遮蔽されるため、
投影平面１０２上では±１次回析光のみの重なりとなり
、光学技術］ンタクトＶｏｊ’１２３、Ａ３ Ｃ１９８
５）ｉ（オイて明記されているように、本来、再生すべ
き空間周波数の２倍の周波数の干渉縞を形成してしまい
、コヒーレント照明下においては微細パターンの投影が
不可能であった。On the other hand, in the conventional reflective optical system shown in FIG. 5, there is no restriction on the wavelength used since it is composed of only a reflective mirror. However, when this optical system is viewed as a re-diffraction optical system, since the O-order diffraction light is blocked by the secondary mirror 105,
On the projection plane 102, only the ±1st-order diffraction light overlaps, and optical technology] Contact Voj'123, A3 C198
5) i (As clearly stated, interference fringes with a frequency twice the spatial frequency to be reproduced were formed, making it impossible to project fine patterns under coherent illumination.
そこで、本発明は、上記従来の問題点を解決するもので
、反射光学系を主としたレンズ構成としてレンズ枚数を
低減し、光の吸収量を極力小さく抑え、紫外域、あるい
は遠紫外域への適用を可能とし、高解像を得ることがで
き、またコヒーレント照明下においても反射鏡による喰
をなくし、０次及び±１次回析光の重なりを得て像形成
を行うことができ、従って微細パターンの投影を行うこ
とができるようにした微細パターン投影光学系を提供し
ようとするものである。Therefore, the present invention solves the above-mentioned conventional problems by reducing the number of lenses by using a lens configuration mainly using a reflective optical system, suppressing the amount of light absorption as much as possible, and extending the light absorption to the ultraviolet region or deep ultraviolet region. can be applied, high resolution can be obtained, and even under coherent illumination, it is possible to eliminate the interference caused by the reflecting mirror and form an image by obtaining the overlap of the zero-order and ±1st-order diffracted light. It is an object of the present invention to provide a fine pattern projection optical system capable of projecting fine patterns.
問題点を解決するための手段
そして上記問題点を解決するための本発明の技術的な手
段は、物点側の屈析光学系及び像点側のカタジオプトリ
ック光学系から成り、上記屈析光学系は複数の屈析部材
が組合わされ、上記カタジオプトリック光学系は基準軸
を中心に回転対称な位相補正部材の曲率の中心に対し、
中心にそれぞれ開口を有する凸面鏡部材及び凹面鏡部材
が同心に配され、上記屈析光学系及びカタジオプトリッ
ク光学系が共軸上で、上記位相補正部材の像点側の面が
絞り位置となるようにこの位相補正部材を境界として結
合され、物点から出た光束が上記屈析光学系を屈析され
ながら通過し、上記カタジオプトリック光学系の位相補
正部材を通過後、一部の光束が凸面鏡部材の開口及び凹
面鏡部材の開口を通過して像点へ到達し、残りの光束が
凹面鏡部材により位相補正部材側に反射され、さらに凸
面鏡部材により位相補正部材とは反対側に反射され、凹
面鏡部材の開口を通過して像点へ到達し、基準軸とは直
角面内で、かつ凹面鏡部材の後方に像形成を行う投影レ
ンズと、上記屈析光学系の物点側焦点面に置かれ、パタ
ーンの空間周波数が高く、コヒーレント光による照明に
より回析光を生じる被投影物体と、照明光束が上記位相
補正部材の曲率中心に集光する如く被投影物体に対して
収れん照明を行う照明光源とを備えたものである。Means for solving the problems and technical means of the present invention for solving the above problems consist of a refractive optical system on the object point side and a catadioptric optical system on the image point side. The analytical optical system is a combination of a plurality of refractive members, and the catadioptric optical system has a rotational symmetry with respect to the center of curvature of the phase correction member, which is rotationally symmetrical about the reference axis.
A convex mirror member and a concave mirror member each having an aperture at the center are arranged concentrically, the refractive optical system and the catadioptric optical system are coaxial, and the image point side surface of the phase correction member is the aperture position. The light flux emitted from the object point passes through the refracting optical system while being refracted, and after passing through the phase correcting member of the catadioptric optical system, some The light flux passes through the aperture of the convex mirror member and the aperture of the concave mirror member to reach the image point, and the remaining light flux is reflected by the concave mirror member toward the phase correction member, and further reflected by the convex mirror member to the side opposite to the phase correction member. , a projection lens that passes through the aperture of the concave mirror member and forms an image in a plane perpendicular to the reference axis and behind the concave mirror member, and a focal plane on the object point side of the refractive optical system. convergent illumination is performed on the projected object such that the illumination light flux is focused on the center of curvature of the phase correction member. It is equipped with an illumination light source.
作 用 上記技術的手段による作用は次のようになる。For production The effects of the above technical means are as follows.
投影光学系の位相補正部材の曲率中心、すなわち絞り面
中心に集光するようにコヒーレント光により被投影物体
を収れん照明し、０次回行光、±１次回折先の輝点スペ
クトルを絞り面上に得る。The object to be projected is convergently illuminated with coherent light so that the light is focused on the center of curvature of the phase correction member of the projection optical system, that is, the center of the aperture surface, and the bright spot spectrum of the 0th-order running light and the ±1st-order diffracted points is focused on the aperture surface. get to.
しかる後、±１次回折先は凹面鏡部材、凸面鏡部材の順
に反射させ、凹面鏡部材の開口より像面へ到達させる。Thereafter, the ±1st-order diffraction points are reflected by the concave mirror member and the convex mirror member in this order, and are made to reach the image plane through the aperture of the concave mirror member.
一方、０次回行光は凸面鏡部材、凹面鏡部材の開口より
像面へ到達させる。ここで、凹面鏡部材及び凸面鏡部材
の曲率中心は絞り面中心に対して同心に配置しであるた
め、凹面鏡部材、凸面鏡部材で反射されて像面へ到達し
た場合と金く同様の光学収差性能が得られ、かつ像面で
の０次回行光、±１次回折先の重なりを得ることができ
、微細パターンの投影が可能となる。また主たる屈析力
を反射系で得ているため、屈析レンズ枚数が低減でき、
紫外域、遠紫外域の短波長での透過率を確保することが
でき、高解像力の投影光学系を得ることができる。On the other hand, the 0th order light reaches the image plane through the apertures of the convex mirror member and the concave mirror member. Here, since the centers of curvature of the concave mirror member and the convex mirror member are arranged concentrically with respect to the center of the diaphragm surface, the optical aberration performance is the same as that when it is reflected by the concave mirror member and the convex mirror member and reaches the image plane. In addition, it is possible to obtain an overlap of the 0th-order traveling light and the ±1st-order diffraction destinations on the image plane, making it possible to project a fine pattern. In addition, since the main refractive power is obtained from the reflective system, the number of refractive lenses can be reduced.
Transmittance at short wavelengths in the ultraviolet region and deep ultraviolet region can be ensured, and a projection optical system with high resolution can be obtained.
実施例
以下、本発明の実施例について図面を参照しながら説明
する。EXAMPLES Hereinafter, examples of the present invention will be described with reference to the drawings.
第１図は本発明の一実施例における微細パターン投影光
学系を示す全体断面図、第２図は投影レンズ部の拡大図
である。第１図及び第２図に示すように合成石英から成
る凸レンズ１、凹レンズ２、凸レンズ３及び凸レンズ４
により物点側の屈析光学系Ｉが構成されており、被投影
物体９は屈析光学系■の焦平面Ｆ上に置かれる。FIG. 1 is an overall sectional view showing a fine pattern projection optical system according to an embodiment of the present invention, and FIG. 2 is an enlarged view of a projection lens section. As shown in FIGS. 1 and 2, a convex lens 1, a concave lens 2, a convex lens 3, and a convex lens 4 made of synthetic quartz
A refractive optical system I on the object point side is constructed, and the object 9 to be projected is placed on the focal plane F of the refractive optical system (2).
一方、位相補正板５、中心に開口０．を有する凹面鏡６
及び中心に開口０２を有する凸面鏡７により像点側のカ
タジオプトリック光学系■が構成されている。このカタ
ジオプトリック光学系■は被投影物体９に対し、位相補
正板５、凸面鏡６、凹面鏡５の順で配置されている。こ
れら屈析光学系Ｉとカタジオプトリック光学系■は共軸
上で、系としての絞りＡＰ位置が位相補正板５の曲率中
心Ｃに一致するよう互いに相対して結合されている。On the other hand, the phase correction plate 5 has an opening at the center. concave mirror 6 having
A catadioptric optical system (2) on the image point side is constituted by a convex mirror 7 having an aperture 02 at the center. This catadioptric optical system (2) has a phase correction plate 5, a convex mirror 6, and a concave mirror 5 arranged in this order with respect to the object 9 to be projected. The refractive optical system I and the catadioptric optical system (2) are coaxially connected to each other so that the aperture AP position of the system coincides with the center of curvature C of the phase correction plate 5.
位相補正板５は基準軸を中心に回転対称となっており、
凸面鏡７及び凹面鏡６はそれぞれ位相補正板５の曲率中
心Ｃに対して同心配置となっている。The phase correction plate 5 is rotationally symmetrical about the reference axis,
The convex mirror 7 and the concave mirror 6 are each arranged concentrically with respect to the center of curvature C of the phase correction plate 5.
本実施例における物点側の開口数は０．０７６、像側の
開口数は０．３８、倍率は１１５である。照明２０はコ
ヒーレント光であり、被投影物体９全体を照らし、屈析
光学系Ｉを通過した後、位相補正板５の曲率中心Ｃに集
光するよう収れん的に照明する。In this example, the numerical aperture on the object side is 0.076, the numerical aperture on the image side is 0.38, and the magnification is 115. The illumination 20 is coherent light that illuminates the entire projection object 9 and, after passing through the refractive optical system I, is convergently illuminated so that the light is focused on the center of curvature C of the phase correction plate 5.
而してコヒーレントで、かつ収れん的な照明２０により
照明された被投影物体９からは、０次回析光Ｄ０、±１
次回析光Ｄ＋４、Ｄ、、さらには高次の回析光が生じ、
投影レンズ（Ｉ＋ＩＩ）へ入射する。本実施例では、投
影レンズの像側の開口数（ＮＡ＝ＳｉｎＯｏ）で決定さ
れる入射角度と被投影物体９からの一次回析光角θ１と
が一致するよう設計しである。そのため、２次回析光以
上の高次の回析光は投影レンズ（Ｉ＋ＩＩ ）へは入射
しない。Therefore, from the projected object 9 illuminated by the coherent and convergent illumination 20, the 0th order diffraction light D0, ±1
The next diffraction light D+4, D, and even higher-order diffraction light are generated,
The light enters the projection lens (I+II). This embodiment is designed so that the angle of incidence determined by the image-side numerical aperture (NA=SinOo) of the projection lens matches the angle of primary diffraction light θ1 from the object 9 to be projected. Therefore, higher-order diffraction light higher than second-order diffraction light does not enter the projection lens (I+II).
投影物体９からの＋１次回析光Ｄ＋１、−１次回行光Ｄ
ｏ次回析光り。はそれぞれ屈析しなから凸レンズ１、凹
レンズ２、凸レンズ３、凸レンズ４、位相補正板５を通
過した後、絞りＡＰ上で各輝点スペクトルＳ十１、Ｓ−
１、Ｓｏに集光し、分離する。その後、±１次回析光Ｄ
＋４、Ｄｌは凹面鏡６により被投影物体９側へ反射され
、さらに凸面鏡７により再度、被投影物体９とは反射側
に反射され、凹面鏡６の開口０．を通過し、投影光学系
（Ｉ＋ＩＩ）の右方へ出射する。一方、０次回析光り。+1st-order analytical light D+1, -1st-order running light D from the projection object 9
o-order analysis light. After passing through convex lens 1, concave lens 2, convex lens 3, convex lens 4, and phase correction plate 5, each bright spot spectrum S11, S-
1. Focus the light on So and separate it. After that, ±1st order diffraction light D
+4, Dl is reflected by the concave mirror 6 toward the projection object 9 side, and further reflected again by the convex mirror 7 toward the reflection side away from the projection object 9, and the aperture 0. and exits to the right of the projection optical system (I+II). On the other hand, 0th order analysis light.
は凸面鏡７の開口０２を通過し、さらに凹面鏡６の開口
０１を通過し、同様に投影光学系（Ｉ十〇 ）の右方へ
出射していく。０次回析光Ｄ０については凹面鏡６、凸
面鏡７の反射を経ていないが、凹面鏡６及び凸面鏡７は
０次回行光Ｄ１の集光点Ｃ（すなわら、絞りＡＰ上の０
点）に対して同心となっているため、第３図に示すよう
に反射した場合と同様の光路を経ることとなるため、光
学収差においては何らの変化もない。passes through the aperture 02 of the convex mirror 7, further passes through the aperture 01 of the concave mirror 6, and similarly exits to the right of the projection optical system (I10). The 0th-order diffracted light D0 has not been reflected by the concave mirror 6 and the convex mirror 7, but the concave mirror 6 and the convex mirror 7
Since the light beam is concentric with respect to the point ), it follows the same optical path as in the case of reflection as shown in FIG. 3, so there is no change in optical aberration.
投影像は０次回行光ｐ０、±１次回析光Ｄ＋４、Ｄ、
が同じ大きさで重なる像平面１Ｍ上において、干渉縞
として形成される。The projected image is 0th order line light p0, ±1st order analytical light D+4, D,
are formed as interference fringes on the image plane 1M where they overlap and have the same size.
また高ＮＡ部を反射系で負担させ、低ＮＡ部を屈析部で
分担することにより、レンズである屈析材料が合成石英
のみであり、枚数も５枚であるため、λ＝２００ｎｍの
波長においても、３０％以上の透過率が得られる。In addition, by sharing the high NA part with the reflective system and the low NA part with the refracting part, the refractive material of the lens is only synthetic quartz, and the number of lenses is 5, so the wavelength of λ = 200 nm Even in this case, a transmittance of 30% or more can be obtained.
発明の効果
以上述べたように本発明によれば、複数の屈析部材から
成る屈析光学系と、位相補正部材、中心に開口を有する
凸面鏡部材及び凹面鏡部材から成るカタジオプトリック
光学系を位相補正部材の像点側の曲率中心が絞りの位置
となるよう共軸上で結合し、被投影物体を絞りの中心に
集光するようにコヒーレント照明することにより、反射
鏡による喰を排し、像形成に０次回析光、±１次回析光
の重なりを得る再回析光学系を実現することができ、微
細パターンの投影が可能となる。また主たる屈析力を反
射系で得ているため、屈析レンズ枚数を低減でき、紫外
域、遠紫外域の短波長での透過率を確保することができ
、高解像力の投影光学系を得ることができる。Effects of the Invention As described above, according to the present invention, a refractive optical system comprising a plurality of refractive members, a phase correction member, a catadioptric optical system comprising a convex mirror member having an aperture in the center, and a concave mirror member are provided. The center of curvature on the image point side of the phase correction member is connected coaxially to the aperture position, and coherent illumination is performed so that the projected object is focused on the center of the aperture, thereby eliminating the interference caused by the reflecting mirror. , it is possible to realize a re-diffraction optical system that obtains the overlap of 0th-order diffraction light and ±1st-order diffraction light for image formation, and it becomes possible to project fine patterns. In addition, since the main refractive power is obtained from the reflective system, the number of refractive lenses can be reduced and transmittance at short wavelengths in the ultraviolet and deep ultraviolet regions can be ensured, making it possible to obtain a projection optical system with high resolution. can.
第１図乃至第３図は本発明の一実施例における微細パタ
ーン投影光学系を示し、第１図は全体断面図、第２図は
投影光学系の拡大図、第３図は０次回析光の通過状態を
示す説明図、第４図は従来の屈析系を用いた投影光学系
の全体断面図、第５図は従来の反射系を用いた反射顕微
鏡用対物鏡の断面図である。
１ ・・凸レンズ、２・・・・・・凹レンズ、ａ・・・
・・・凸レンズ１．４・・・・・・凸レンズ、５・・・
・・位相補正板、６・・・・・・凹面鏡、７・・・・・
・凸面鏡、８・・・・・・投影像、９・・・・・・被投
影物体、２０・・・・・・照明、ＡＰ・・・・・・絞り
、■・・・・・・屈析光学系、■・・・・・・カタジオ
プトリック光学系。1 to 3 show a fine pattern projection optical system according to an embodiment of the present invention, FIG. 1 is an overall cross-sectional view, FIG. 2 is an enlarged view of the projection optical system, and FIG. 3 is a 0th-order analyzed light beam. FIG. 4 is an overall sectional view of a projection optical system using a conventional refracting system, and FIG. 5 is a sectional view of an objective mirror for a reflection microscope using a conventional reflecting system. 1... Convex lens, 2... Concave lens, a...
... Convex lens 1.4 ... Convex lens, 5 ...
... Phase correction plate, 6 ... Concave mirror, 7 ...
・Convex mirror, 8...Projected image, 9...Projected object, 20...Illumination, AP...Aperture, ■...Deflection Analytical optical system, ■... Catadioptric optical system.
Claims (2)
ック光学系から成り、上記屈析光学系は複数の屈析部材
が組合わされ、上記カタジオプトリック光学系は基準軸
を中心に回転対称な位相補正部材の曲率の中心に対し、
中心にそれぞれ開口を有する凸面鏡部材及び凹面鏡部材
が同心に配され、上記屈析光学系及びカタジオプトリッ
ク光学系が共軸上で、上記位相補正部材の像点側の面が
絞り位置となるようにこの位相補正部材を境界として結
合され、物点から出た光束が上記屈析光学系を屈析され
ながら通過し、上記カタジオプトリック光学系の位相補
正部材を通過後、一部の光束が凸面鏡部材の開口及び凹
面鏡部材の開口を通過して像点へ到達し、残りの光束が
凹面鏡部材により位相補正部材側に反射され、さらに凸
面鏡部材により位相補正部材とは反対側に反射され、凹
面鏡部材の開口を通過して像点へ到達し、基準軸とは直
角面内で、かつ凹面鏡部材の後方に像形成を行う投影レ
ンズと、上記屈析光学系の物点側焦点面に置かれ、パタ
ーンの空間周波数が高く、コヒーレント光による照明に
より回析光を生じる被投影物体と、照明光束が上記位相
補正部材の曲率中心に集光する如く被投影物体に対して
収れん照明を行う照明光源とを備えたことを特徴とする
微細パターン投影光学系。(1) Consists of a refractive optical system on the object point side and a catadioptric optical system on the image point side. With respect to the center of curvature of the phase correction member that is rotationally symmetrical about ,
A convex mirror member and a concave mirror member each having an aperture at the center are arranged concentrically, the refractive optical system and the catadioptric optical system are coaxial, and the image point side surface of the phase correction member is the aperture position. The light flux emitted from the object point passes through the refracting optical system while being refracted, and after passing through the phase correcting member of the catadioptric optical system, some The light flux passes through the aperture of the convex mirror member and the aperture of the concave mirror member to reach the image point, and the remaining light flux is reflected by the concave mirror member toward the phase correction member, and further reflected by the convex mirror member to the side opposite to the phase correction member. , a projection lens that passes through the aperture of the concave mirror member and forms an image in a plane perpendicular to the reference axis and behind the concave mirror member, and a focal plane on the object point side of the refractive optical system. convergent illumination is performed on the projected object such that the illumination light flux is focused on the center of curvature of the phase correction member. A fine pattern projection optical system characterized by comprising an illumination light source.
系の開口数が大きい特許請求の範囲第１項記載の微細パ
ターン投影光学系。(2) The fine pattern projection optical system according to claim 1, wherein the numerical aperture of the catadioptric optical system is larger than the numerical aperture of the refractive optical system.
Priority Applications (4)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP61159050A JPS6314112A (en) | 1986-07-07 | 1986-07-07 | Projection optical system for fine pattern |
| US07/043,620 US4757354A (en) | 1986-05-02 | 1987-04-28 | Projection optical system |
| EP87106243A EP0243950B1 (en) | 1986-05-02 | 1987-04-29 | Optical projection system |
| DE8787106243T DE3784963T2 (en) | 1986-05-02 | 1987-04-29 | OPTICAL PROJECTION SYSTEM. |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP61159050A JPS6314112A (en) | 1986-07-07 | 1986-07-07 | Projection optical system for fine pattern |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPS6314112A true JPS6314112A (en) | 1988-01-21 |
Family
ID=15685133
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP61159050A Pending JPS6314112A (en) | 1986-05-02 | 1986-07-07 | Projection optical system for fine pattern |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS6314112A (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2002056114A3 (en) * | 2001-01-09 | 2003-12-11 | Zeiss Carl Smt Ag | Projection system for euv lithography |
| US7151592B2 (en) | 1999-02-15 | 2006-12-19 | Carl Zeiss Smt Ag | Projection system for EUV lithography |
| JP2009044143A (en) * | 2007-07-18 | 2009-02-26 | Asml Holding Nv | Catadioptric optical system for scatterometry |
-
1986
- 1986-07-07 JP JP61159050A patent/JPS6314112A/en active Pending
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US7151592B2 (en) | 1999-02-15 | 2006-12-19 | Carl Zeiss Smt Ag | Projection system for EUV lithography |
| WO2002056114A3 (en) * | 2001-01-09 | 2003-12-11 | Zeiss Carl Smt Ag | Projection system for euv lithography |
| JP2009044143A (en) * | 2007-07-18 | 2009-02-26 | Asml Holding Nv | Catadioptric optical system for scatterometry |
| US8107173B2 (en) | 2007-07-18 | 2012-01-31 | Asml Holding N.V. | Catadioptric optical system for scatterometry |
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