JPH0758003A - Projection aligner - Google Patents

Projection aligner

Info

Publication number
JPH0758003A
JPH0758003A JP28832993A JP28832993A JPH0758003A JP H0758003 A JPH0758003 A JP H0758003A JP 28832993 A JP28832993 A JP 28832993A JP 28832993 A JP28832993 A JP 28832993A JP H0758003 A JPH0758003 A JP H0758003A
Authority
JP
Japan
Prior art keywords
exposure
substrate
optical axis
imaging
positions
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.)
Granted
Application number
JP28832993A
Other languages
Japanese (ja)
Other versions
JP2654418B2 (en
Inventor
Hiroshi Fukuda
宏 福田
Toshishige Kurosaki
利栄 黒崎
Norio Hasegawa
昇雄 長谷川
Toshihiko Tanaka
稔彦 田中
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Hitachi Ltd
Original Assignee
Hitachi Ltd
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Filing date
Publication date
Application filed by Hitachi Ltd filed Critical Hitachi Ltd
Priority to JP5288329A priority Critical patent/JP2654418B2/en
Publication of JPH0758003A publication Critical patent/JPH0758003A/en
Application granted granted Critical
Publication of JP2654418B2 publication Critical patent/JP2654418B2/en
Anticipated expiration legal-status Critical
Expired - Fee Related legal-status Critical Current

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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
    • G03F7/708—Construction of apparatus, e.g. environment aspects, hygiene aspects or materials
    • 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
    • G03F9/00—Registration or positioning of originals, masks, frames, photographic sheets or textured or patterned surfaces, e.g. automatically
    • G03F9/70—Registration or positioning of originals, masks, frames, photographic sheets or textured or patterned surfaces, e.g. automatically for microlithography

Landscapes

  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Health & Medical Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Environmental & Geological Engineering (AREA)
  • Epidemiology (AREA)
  • Public Health (AREA)
  • Exposure Of Semiconductors, Excluding Electron Or Ion Beam Exposure (AREA)

Abstract

PURPOSE:To increase an effective focus margin of an exposure optical system without flattening a surface of a substrate by repeatedly projecting and exposing the same mask pattern image to a plurality of positions (imaging points) at different distances from the surface of the substrate at an optical axis of the optical system. CONSTITUTION:A computer 7 previously stores pieces of information of a plurality of positions (imaging points) and pieces of information of the imaging points at different distances from a surface of a substrate at an optical axis of a projection optical system 2. In this case, an exposure mode means, in addition number of a plurality of imaging surfaces set in one time exposure sequence, a position at an optical axis of the imaging surface and an amount of exposure at each imaging surface. When the number of the imaging surfaces are two or more, the substrate is moved to the exposure position of the system 2 by driving an X-Y stage 3. Then, a control of the sequence is delivered to a multiple imaging exposure control system 11.

Description

【発明の詳細な説明】Detailed Description of the Invention

【０００１】[0001]

【産業上の利用分野】本発明は、半導体素子、磁気バブ
ル素子、超電導素子等の固体素子における微細加工に用
いて好適な投影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 projection exposure apparatus suitable for use in fine processing of solid-state elements such as semiconductor elements, magnetic bubble elements and superconducting elements.

【０００２】[0002]

【従来の技術】投影露光法における光学系の焦点裕度
は、投影レンズの口径と露光波長に強く依存する。即
ち、投影レンズの焦点深度は、その口径の２乗に反比例
し、露光波長に正比例するが、解像度を向上させる目的
で投影レンズの口径を大きくし、露光波長を短くする
と、焦点深度が減少する結果、投影レンズの像面歪や基
板表面の凹凸段差、基板の傾斜等に対する対処が困難に
なる。2. Description of the Related Art The focus latitude of an optical system in a projection exposure method strongly depends on the aperture of a projection lens and the exposure wavelength. That is, the depth of focus of the projection lens is inversely proportional to the square of the aperture and is directly proportional to the exposure wavelength, but if the aperture of the projection lens is increased and the exposure wavelength is shortened for the purpose of improving resolution, the depth of focus decreases. As a result, it becomes difficult to cope with the image distortion of the projection lens, the uneven surface of the substrate surface, the inclination of the substrate, and the like.

【０００３】比較的微細なパタンによる凹凸段差は、例
えば多層レジスト法〔ジャーナル・オブ・サイエンス・
アンド・テクノロジー（Journal of Vacuum Science an
d Technology）Ｂ１(4)(１９８３）第１２３５頁〜第１
２４０頁参照〕によって平滑化することが可能である
が、この方法は、大面積パタンによる凹凸段差の影響を
完全に防止することが出来ない。従来の投影露光装置
は、結像面を光軸上の１点に固定した状態でマスクパタ
ンの露光を行なうものであるため、基板表面の凹凸段差
の平均的な位置に結像面を設定して露光を行なう必要が
あり、凹凸段差が投影レンズの焦点深度より大きい場合
は、段差の上部又は下部において解像不良が生ずるから
である。The unevenness due to the relatively fine pattern can be formed, for example, by a multi-layer resist method [Journal of Science.
And Technology (Journal of Vacuum Science an
d Technology) B1 (4) (1983) pp. 1235-1.
However, this method cannot completely prevent the influence of the uneven step due to the large area pattern. In the conventional projection exposure apparatus, since the mask pattern is exposed with the image forming surface fixed at one point on the optical axis, the image forming surface is set at an average position of the unevenness of the substrate surface. This is because it is necessary to carry out exposure, and if the uneven step is larger than the depth of focus of the projection lens, poor resolution occurs at the upper part or the lower part of the step.

【０００４】[0004]

【発明が解決しようとする課題】近年、半導体集積回路
の高集積化に伴い、パタンの微細化と凹凸段差の増大に
対する対策の必要性が強まりつつある。従って、投影露
光法を用いてパタン形成を行なう場合は、凹凸段差の増
大に対応するため、より大きな焦点深度を有する光学系
を使用することが必要であるが、一方では、マスクパタ
ンの解像度を向上させるため、投影レンズの口径を大き
くするか、露光波長を短くすることが必要であり、この
場合、焦点深度は、逆に減少する。しかも、マスクパタ
ンの結像面は、投影レンズの像面歪により、完全に平面
化することが出来ないほか、基板表面には傾斜があるた
め、凹凸段差に対応可能な焦点深度を基板の被露光領域
の全面にわたって確保することは、極めて困難である。In recent years, along with the high integration of semiconductor integrated circuits, it is becoming increasingly necessary to take measures against the miniaturization of patterns and the increase of uneven steps. Therefore, when pattern formation is performed by using the projection exposure method, it is necessary to use an optical system having a larger depth of focus in order to cope with an increase in unevenness in level. In order to improve, it is necessary to increase the aperture of the projection lens or shorten the exposure wavelength, in which case the depth of focus decreases conversely. Moreover, the image plane of the mask pattern cannot be perfectly flattened due to the image plane distortion of the projection lens, and since the substrate surface has an inclination, the depth of focus that can cope with uneven steps is not enough. It is extremely difficult to secure the entire exposure area.

【０００５】多層レジスト法は、大面積パタンの凹凸段
差を完全に平坦化することが困難であり、仮に完全に平
坦化することが出来たとしても、レンズの像面歪のた
め、マスクパタンの結像面を基板表面に一致させること
が出来ず、上記問題点に対処することが困難である。In the multi-layer resist method, it is difficult to completely flatten the uneven steps of a large area pattern, and even if it is possible to completely flatten it, the mask image pattern distortion causes a lens pattern distortion. Since the image plane cannot be made to coincide with the substrate surface, it is difficult to deal with the above problems.

【０００６】従って、本発明の目的は、基板表面の平坦
化によらないで光学系の実効的焦点裕度を増大するため
の新しい装置を提案することにより、基板表面の凹凸段
差の増大、基板の傾斜、投影レンズの像面歪、投影レン
ズの大口径化、露光光の短波長化等に伴う焦点裕度の減
少を防止することにある。Therefore, an object of the present invention is to propose a new device for increasing the effective focus latitude of an optical system without depending on the flattening of the substrate surface, thereby increasing the unevenness of the substrate surface, Is to prevent the reduction of the focus margin due to the inclination of the, the image plane distortion of the projection lens, the enlargement of the diameter of the projection lens, the shortening of the wavelength of the exposure light and the like.

【０００７】[0007]

【課題を解決するための手段】前記課題（光学系の実効
的焦点深度の増大）は、露光光学系の光軸上における基
板表面からの距離が互いに異なる複数の位置（結像点）
に同一のマスクパタン像を繰り返して投影露光すること
によって解決することが出来る。ここで「結像点」の語
は、マスクパタンの光学系に対する共役面上の点を意味
する。The above-mentioned problem (increase in effective depth of focus of the optical system) is solved by a plurality of positions (image points) having different distances from the substrate surface on the optical axis of the exposure optical system.
Can be solved by repeatedly projecting and exposing the same mask pattern image. Here, the term "imaging point" means a point on the conjugate plane of the mask pattern with respect to the optical system.

【０００８】本発明者等は、基板表面のレジスト層に対
して相対的に異なる光軸上の複数の位置にマスクパタン
の共役面（即ち結像面）を設定し、これらの複数の位置
にマスクパタンの像を繰り返して露光した。結像点が単
一である従来の場合と、それぞれ３μｍ、３．５μｍ及
び５μｍ離れて二つの結像点を設定した本発明の場合に
ついて、光軸方向の位置と０．７μｍラインアンドスペ
ースの光強度コントラストの計算値の関係を比較した結
果を図５に示す。光軸方向の原点は、単一結像点及び二
つの結像点の中心においてある。同図から明らかなよう
に、異なる二つの位置に結像点を設定した本発明の場合
は、結像点が単一である従来の場合と比較し、合成光の
光強度コントラストの最高値が減少するものの、より広
い光軸上の範囲で一定以上の光強度コントラストを維持
している。従って、二つの結像点相互間の距離を最適化
することにより、光軸方向の或る範囲内で一定の光強度
コントラストを実現することが可能となる。The present inventors set the conjugate planes (that is, the image planes) of the mask pattern at a plurality of positions on the optical axis which are relatively different from the resist layer on the surface of the substrate, and set them at these plurality of positions. The image of the mask pattern was repeatedly exposed. Regarding the conventional case where a single image forming point is provided and the case of the present invention where two image forming points are set apart from each other by 3 μm, 3.5 μm and 5 μm respectively, the position in the optical axis direction and the line and space of 0.7 μm FIG. 5 shows the result of comparison of the calculated values of the light intensity contrast. The origin in the optical axis direction is at the center of a single image formation point and two image formation points. As is clear from the figure, in the case of the present invention in which the image forming points are set at two different positions, the maximum value of the light intensity contrast of the combined light is higher than that in the conventional case where the image forming point is single. Although decreasing, the light intensity contrast is maintained above a certain level in a wider range on the optical axis. Therefore, by optimizing the distance between the two image forming points, it becomes possible to realize a constant light intensity contrast within a certain range in the optical axis direction.

【０００９】もっとも、実効的焦点裕度の増加率は、使
用するレジスト、現像液、コントラスト・エンハンスメ
ント・マテリアル等の材料のほか、プロセスによる解像
可能な光強度コントラストの下限値に依存する。例え
ば、二つの結像点相互間の距離を３．５μｍに設定した
ときの実効的焦点裕度の増加率は、解像可能な光強度コ
ントラストの下限値が０．５の場合、４５％であるが、
同下限値が０．４である場合は、約７０％になる。な
お、同下限値が０．３である場合は、光軸上の三つの位
置に結像点を設定することが可能であり、これによって
実効的焦点裕度を約１５０％向上させることが出来た。However, the rate of increase in the effective focus latitude depends on the resist, developer, contrast enhancement material, and other materials used, as well as the lower limit of the light intensity contrast that can be resolved by the process. For example, when the distance between two image formation points is set to 3.5 μm, the effective focus margin increase rate is 45% when the lower limit of the resolvable light intensity contrast is 0.5. But
When the lower limit value is 0.4, it is about 70%. When the lower limit value is 0.3, it is possible to set the image forming points at three positions on the optical axis, which can improve the effective focus margin by about 150%. It was

【００１０】[0010]

【作用】基板の被露光領域の全面にわたり、凹凸段差の
上下に位置するレジスト層にマスクパタン像を良好な解
像度で結像させるには、投影レンズの像面歪、基板の平
坦度及び凹凸段差の高さで決まる光軸方向の或る範囲に
おいて、一定水準以上の光強度コントラストを保証する
必要がある。一方、投影露光の場合、レジスト層にマス
クパタン像を忠実に反映させることが出来る光軸上の位
置は、マスクパタンの共役面即ち結像面の近傍だけであ
り、そこから遠ざかるにつれて光強度コントラストが急
激に低下する。In order to form a mask pattern image with a good resolution on the resist layer located above and below the uneven surface over the entire exposed region of the substrate, the image plane distortion of the projection lens, the flatness of the substrate and the uneven surface It is necessary to guarantee a light intensity contrast above a certain level in a certain range in the optical axis direction determined by the height of the. On the other hand, in the case of projection exposure, the position on the optical axis where the mask pattern image can be faithfully reflected on the resist layer is only in the vicinity of the conjugate plane of the mask pattern, that is, the image plane, and the light intensity contrast increases as the distance from the conjugate plane increases. Drops sharply.

【００１１】光軸上の複数の位置に結像点を設定した場
合の光強度コントラストは、個々の結像点における光強
度コントラストの平均的な値となる。換言すれば、単一
結像点の場合は、光軸方向の広い範囲の全域にわたって
所望の光強度コントラストを実現することが出来ない
が、光軸上の複数の位置に結像点を設定した場合は、複
数のマスクパタン像を重ね合わせることが出来る結果、
広い範囲の全域にわたって一定水準以上の光強度コント
ラストを実現することが可能となる。The light intensity contrast when the image forming points are set at a plurality of positions on the optical axis is an average value of the light intensity contrasts at the individual image forming points. In other words, in the case of a single image forming point, a desired light intensity contrast cannot be realized over a wide range in the optical axis direction, but the image forming points are set at a plurality of positions on the optical axis. In the case, as a result of being able to superimpose multiple mask pattern images,
It is possible to realize a light intensity contrast above a certain level over a wide range.

【００１２】[0012]

【実施例】〈実施例１〉図１に示した実施例は、レチク
ル１、投影光学系２、ＸＹステージ３及びＺステージ４
からなる基板ステージ、各ステージの位置を感知するた
めのＸＹセンサ５及びＺセンサ６のほか、装置全体の制
御を行なう制御系及び通常の投影露光装置に必要な各種
構成要素をもって構成されている。なお、Ｚ軸は、光軸
方向にとり、Ｘ軸及びＹ軸は、光軸と垂直な平面内にと
るものとする。制御系は、装置全体を統制するための計
算機７のほか、当該計算機の命令によって露光シャッタ
ーの開閉を行なわせるための露光シャッター制御系８、
ＸＹステージを指定された位置に駆動するためのＸＹ制
御系９及びＺステージを指定された位置に駆動するため
のＺ制御系１０をもって構成されており、かつ、光軸方
向だけの基板の移動と露光シャッター制御系８への指令
を行なうための多重結像露光制御系１１を含む。計算機
７及び各制御系８〜１１は、バスラインを介して相互に
接続されている。EXAMPLE 1 Example 1 shown in FIG. 1 is a reticle 1, a projection optical system 2, an XY stage 3 and a Z stage 4.
In addition to the substrate stage consisting of, an XY sensor 5 and a Z sensor 6 for sensing the position of each stage, a control system for controlling the entire apparatus and various constituent elements necessary for a normal projection exposure apparatus. Note that the Z axis is in the optical axis direction, and the X axis and the Y axis are in a plane perpendicular to the optical axis. The control system includes a computer 7 for controlling the entire apparatus, and an exposure shutter control system 8 for opening and closing the exposure shutter according to a command from the computer.
It comprises an XY control system 9 for driving the XY stage to a designated position and a Z control system 10 for driving the Z stage to a designated position, and the movement of the substrate only in the optical axis direction. A multiplex image forming exposure control system 11 for giving a command to the exposure shutter control system 8 is included. The computer 7 and the control systems 8 to 11 are connected to each other via a bus line.

【００１３】計算機７には、投影光学系２の光軸上にお
ける基板表面からの距離が互いに異なる複数の位置（結
像点）の情報及び各結像点における露光モードの情報が
予め記憶されている。ここで「露光モード」とは、１回
の露光シーケンスにおいて設定される複数の結像面の数
のほか、当該結像面の光軸上の位置及び個々の結像面ご
との露光量のことをいう。露光モードが指定する結像面
の数が一つである場合は、通常のステップ・アンド・リ
ピート方式によって露光を直接制御し、結像面の数が二
つ以上である場合は、ＸＹステージ３の駆動により、基
板を投影光学系２の露光位置に移動した後、露光シーケ
ンスの制御を多重結像露光制御系１１に引き渡す。結像
面の数が二つである場合の露光シーケンスを図２に示
す。Information on a plurality of positions (image points) at different distances from the substrate surface on the optical axis of the projection optical system 2 and information on the exposure mode at each image point are stored in advance in the computer 7. There is. Here, the "exposure mode" refers to the number of a plurality of image planes set in one exposure sequence, the position of the image planes on the optical axis, and the exposure amount for each image plane. Say. When the number of image planes designated by the exposure mode is one, the exposure is directly controlled by the normal step-and-repeat method. When the number of image planes is two or more, the XY stage 3 is used. After the substrate is moved to the exposure position of the projection optical system 2 by driving, the exposure sequence control is transferred to the multiplex imaging exposure control system 11. FIG. 2 shows an exposure sequence when the number of image planes is two.

【００１４】以下、本実施例の装置の動作を図２を参照
して説明する。多重結像露光制御系１１は、Ｚステージ
４を駆動し、基板表面に対する結像点の相対位置を例え
ば図３ａに示したように設定する。この場合、Ｚステー
ジ４の移動に伴って発生するＸＹ方向の基板のずれは、
ＸＹセンサ５を介してＸＹ制御系９へフィードバックさ
れ、ＸＹステージ３の駆動によって補正されるので、基
板移動は、事実上、光軸方向だけになる。多重結像露光
制御系１１は、指定された露光位置に基板が正しく設定
されたことを確認した後、各結像面に対して所定時間の
露光を行なうよう、露光シャッター制御系８へ指令を発
し、露光(１)が実行される。露光(１)の終了を確認後、
多重結像露光制御系１１は、基板を光軸方向に移動し、
基板表面に対する結像面の相対位置を例えば図３Ｂｂに
示すように設定して露光(２)を実行させる。結像面の数
が三つ以上の場合は、同様の露光操作を結像面の数だけ
繰り返して行なう。特定の被露光領域に対する露光動作
が全て完了すると、計算機７は、ＸＹステージ３を駆動
し、基板表面の次の被露光領域が投影光学系２の露光位
置に来るように基板を移動する。以上の露光シーケンス
のタイミングを図４ａに示す。参考のため、露光モード
の結像面の数が一つだけである従来装置のタイミングを
図４ｂに示す。従来装置では、同図に示したシーケンス
でしか露光を行なうことが出来なかった。The operation of the apparatus of this embodiment will be described below with reference to FIG. The multiple imaging exposure control system 11 drives the Z stage 4 and sets the relative position of the imaging point with respect to the substrate surface as shown in FIG. 3a, for example. In this case, the displacement of the substrate in the XY directions caused by the movement of the Z stage 4 is
It is fed back to the XY control system 9 via the XY sensor 5 and is corrected by the drive of the XY stage 3, so that the substrate movement is virtually only in the optical axis direction. After confirming that the substrate has been correctly set at the designated exposure position, the multiplex image formation exposure control system 11 issues a command to the exposure shutter control system 8 to expose each image formation surface for a predetermined time. And the exposure (1) is executed. After confirming the end of exposure (1),
The multiple imaging exposure control system 11 moves the substrate in the optical axis direction,
Exposure (2) is executed by setting the relative position of the image plane with respect to the substrate surface as shown in FIG. 3Bb, for example. When the number of image planes is three or more, the same exposure operation is repeated by the number of image planes. When all the exposure operations for the specific exposed region are completed, the computer 7 drives the XY stage 3 and moves the substrate so that the next exposed region on the substrate surface comes to the exposure position of the projection optical system 2. The timing of the above exposure sequence is shown in FIG. 4a. For reference, the timing of the conventional apparatus having only one image plane in the exposure mode is shown in FIG. 4b. In the conventional apparatus, exposure could be performed only in the sequence shown in FIG.

【００１５】本実施例では、光軸方向における基板の移
動と露光を別々のタイミングで行なっているが、基板を
光軸方向に移動しながら断続的に露光を行なうことも可
能である。また、ステップ・アンド・リピート法によ
り、例えば基板表面から光軸方向−２μｍの位置におけ
る露光を全ての被露光領域に対して行なった後、基板を
光軸方向に移動し、同じくステップ・アンド・リピート
法により、例えば光軸方向＋２μｍの位置における露光
を全ての被露光領域に対して行なうことも可能である。
但し、基板は、個々の被露光領域に対する露光時間中、
固定されていなければならない。In this embodiment, the movement of the substrate in the optical axis direction and the exposure are performed at different timings, but it is also possible to perform the exposure intermittently while moving the substrate in the optical axis direction. Also, by the step-and-repeat method, for example, after exposure is performed on the entire exposed region at a position of −2 μm from the substrate surface in the optical axis direction, the substrate is moved in the optical axis direction and the same step By the repeat method, it is also possible to perform exposure at a position of +2 μm in the optical axis direction, for all exposed regions.
However, during exposure time for each exposed area, the substrate
Must be fixed.

【００１６】本発明者等は、本実施例の装置を使用し、
種々の高さの凹凸段差を有する基板表面上に１μｍピッ
チの格子パタンや０．５μｍ径の穴パタン等を露光して
現像する実験を行なった。格子パタンの場合、従来の単
一結像面による露光では、基板表面凹凸段差の上下にお
ける良好な解像度を被露光領域の全面にわたって実現す
るためには、凹凸段差の高さが０．５μｍ以下であるこ
とが必要であるが、本実施例の場合は、レジスト表面を
挟んで光軸方向に互いに３μｍ離れた二つの位置に結像
面を設定することにより、凹凸段差が２μｍの場合で
も、被露光領域の全面にわたって良好な解像度をもって
露光することが出来た。また、穴パタンの場合は、光軸
方向に互いに３μｍ離れた三つの位置に結像面を設定す
ることにより、解像可能な段差高さを１０μｍまで拡大
させることが出来た。このような効果は、多層レジスト
法、高コントラスト現像液、高コントラストレジスト、
コントラスト・エンハンスメント・マテリアル等を用い
ることにより、更に増大させることが出来る。The present inventors have used the device of this embodiment,
Experiments were carried out in which a grid pattern with a pitch of 1 μm, a hole pattern with a diameter of 0.5 μm, and the like were exposed and developed on the surface of a substrate having unevenness steps of various heights. In the case of the lattice pattern, in the conventional exposure using a single image plane, in order to realize good resolution above and below the uneven surface of the substrate surface over the entire exposed region, the uneven height should be 0.5 μm or less. However, in the case of the present embodiment, even if the uneven step is 2 μm, even if the uneven step is 2 μm, the image forming plane is set at two positions separated from each other by 3 μm in the optical axis direction across the resist surface. It was possible to perform exposure with good resolution over the entire exposed area. Further, in the case of the hole pattern, the height of the resolvable step could be increased to 10 μm by setting the image forming planes at three positions separated from each other by 3 μm in the optical axis direction. Such effects are obtained by the multi-layer resist method, high contrast developer, high contrast resist,
It can be further increased by using contrast enhancement materials.

【００１７】本実施例では、基板ステージを光軸方向に
移動させることにより、基板表面に対する結像面の相対
位置の変更を行なったが、この種の相対位置変更は、他
の公知の方法、例えばレンズとレンズとの間を密閉し、
その密閉空間にガスを注入してガスを圧力を変化させる
方法や、レチクル又はレンズを光軸方向に移動させる等
の方法によって実現可能である。なお、エキシマレーザ
を光源とする投影露光装置に本発明の多重結像制御系を
組み合わせたところ、従来のｉ-line、ｇ-line等の紫外
線光源を用いた場合と同様、実効的な焦点裕度増大効果
を得ることが可能となり、エキシマレーザ影露光装置特
有の焦点深度の不足を克服することが出来た。このほ
か、投影露光系をテレセントリックとすることにより、
結像面位置の変更に伴う縮小率の変動をなくすることが
可能となり、チップ全体のパタン寸法精度を向上させる
ことが出来た。In this embodiment, the relative position of the image plane with respect to the substrate surface is changed by moving the substrate stage in the optical axis direction. However, this kind of relative position change can be performed by another known method. For example, seal between the lens,
This can be realized by a method of injecting gas into the closed space and changing the pressure of the gas, or a method of moving the reticle or lens in the optical axis direction. When the multiple exposure control system of the present invention is combined with a projection exposure apparatus using an excimer laser as a light source, the effective focus range is the same as when a conventional ultraviolet light source such as i-line or g-line is used. It became possible to obtain the effect of increasing the degree of focus, and it was possible to overcome the lack of depth of focus peculiar to the excimer laser shadow exposure apparatus. In addition, by making the projection exposure system telecentric,
It became possible to eliminate the fluctuation of the reduction ratio due to the change of the image plane position, and the pattern dimensional accuracy of the entire chip could be improved.

【００１８】〈実施例２〉空気と異なる屈折率を有し、
かつ、露光波長に対して透明な物質からなる平板状又は
レンズ状の焦点調整部材を使用し、当該部材を光学系中
に挿脱自在に設置することによって投影露光装置を構成
した。焦点調整部材は、光学系中に挿入することによっ
て基板近傍における結像面の位置を光軸方向でのみ所望
の距離だけ変更又は移動することが出来るよう、その厚
さ、屈折率及び光軸との直交度等を設定した。同部材
は、厚さ及び屈折率が異なるものを複数枚組み合わせて
使用することも可能であり、この場合は、結像面の位置
をより自由に変更又は移動することが出来る。<Example 2> Having a refractive index different from that of air,
A projection exposure apparatus is constructed by using a flat plate-shaped or lens-shaped focus adjusting member made of a material transparent to the exposure wavelength and installing the member in an optical system so that the member can be inserted and removed. The focus adjusting member has a thickness, a refractive index and an optical axis so that the position of the image plane near the substrate can be changed or moved by a desired distance only in the optical axis direction by inserting the focus adjusting member into the optical system. The degree of orthogonality and the like were set. This member can be used by combining a plurality of members having different thicknesses and refractive indexes, and in this case, the position of the image plane can be changed or moved more freely.

【００１９】焦点調整部材の挿脱制御は、実施例１の場
合と同様の機能を有する多重結像制御系に用いて行な
い、基板上の被露光領域に対する露光操作中、任意のタ
イミングをもって露光を中断し、焦点調整部材を出し入
れして基板に対する結像面の位置を変更又は移動させ
た。本実施例の装置を用いて実施例１の場合と同様の実
験を行なった結果、同様の効果を確認することが出来
た。The insertion / removal control of the focus adjusting member is carried out by using a multiple image forming control system having the same function as in the first embodiment, and the exposure is performed at an arbitrary timing during the exposure operation on the exposed region on the substrate. After that, the focus adjusting member was taken out and in to change or move the position of the image plane with respect to the substrate. As a result of conducting the same experiment as in the case of Example 1 using the apparatus of this example, the same effect could be confirmed.

【００２０】〈実施例３〉投影露光装置の光学系全体を
密閉容器内に収納し、当該容器内の気圧を変化させて任
意の値に設定することが出来るように構成した。そし
て、基板に対する露光操作中、任意のタイミングをもっ
て露光を中断し、密閉容器内の気圧を速やかに変化させ
た後、再び露光を開始した結果、露光中断の前後におい
てマスクパタンの結像面の位置を変更又は移動させるこ
とが出来た。密閉容器内の気圧を緩やかに変化させるこ
とにより、マスクパタンの結像面を光軸方向に移動しな
がら露光することも可能である。気圧の制御は、実施例
１の場合と同様の機能を有する多重結像制御系を用いて
行なった。本実施例の装置を用いて実施例１と同様の実
験を行なった結果、同様の効果を確認することが出来
た。<Embodiment 3> The entire optical system of the projection exposure apparatus is housed in a closed container, and the atmospheric pressure in the container can be changed to be set to an arbitrary value. Then, during the exposure operation for the substrate, the exposure is interrupted at an arbitrary timing, the atmospheric pressure in the closed container is rapidly changed, and then the exposure is restarted.As a result, the position of the image plane of the mask pattern before and after the interruption of the exposure is determined. Could be changed or moved. By gently changing the atmospheric pressure in the closed container, it is possible to perform exposure while moving the image forming surface of the mask pattern in the optical axis direction. The atmospheric pressure was controlled by using the multiplex imaging control system having the same function as in the first embodiment. As a result of conducting the same experiment as in Example 1 using the apparatus of this example, the same effect could be confirmed.

【００２１】[0021]

【発明の効果】本発明によれば、投影露光装置の実効的
焦点裕度を格段に増大させることが可能であり、投影レ
ンズの大口径化、像面歪、基板表面の凹凸段差の増大に
充分対処することが出来る。実効的焦点裕度の増大量
は、使用する材料やプロセス又はマスクパタンの種類等
にも依存するが、格子パタンの場合、最大１５０％程度
まで実効的焦点裕度を増大させることが出来た。穴パタ
ンの場合は、結像面の数を多く設定することにより、焦
点深度を事実上無制限に増大することが出来た。According to the present invention, it is possible to remarkably increase the effective focus latitude of the projection exposure apparatus, and to increase the diameter of the projection lens, the image plane distortion, and the unevenness of the surface of the substrate. I can deal with it enough. The amount of increase in the effective focus latitude depends on the material and process used, the type of mask pattern, etc., but in the case of the lattice pattern, the effective focus latitude could be increased up to about 150%. In the case of the hole pattern, the depth of focus could be increased virtually without limit by setting a large number of image planes.

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

【図１】本発明に係る投影露光装置の一実施例を示す構
成図FIG. 1 is a configuration diagram showing an embodiment of a projection exposure apparatus according to the present invention.

【図２】前記実施例の動作シーケンスを説明するための
フロ−チャートFIG. 2 is a flow chart for explaining the operation sequence of the above embodiment.

【図３】前記実施例の動作概念図FIG. 3 is a conceptual diagram of the operation of the embodiment.

【図４】前記実施例の動作を示すタイミング図FIG. 4 is a timing chart showing the operation of the embodiment.

【図４】本発明の作用を説明するための曲線図FIG. 4 is a curve diagram for explaining the operation of the present invention.

【符号の説明】[Explanation of symbols]

４…Ｚステージ ６…Ｚセンサ ７…計算機 ８…露光シャッター制御系 １０…Ｚ制御系 １１…多重結像露光制御系 4 ... Z stage 6 ... Z sensor 7 ... Calculator 8 ... Exposure shutter control system 10 ... Z control system 11 ... Multiple imaging exposure control system

─────────────────────────────────────────────────────
─────────────────────────────────────────────────── ───

【手続補正書】[Procedure amendment]

【提出日】平成６年６月２４日[Submission date] June 24, 1994

【手続補正１】[Procedure Amendment 1]

【補正対象書類名】明細書[Document name to be amended] Statement

【補正対象項目名】図面の簡単な説明[Name of item to be corrected] Brief description of the drawing

【補正方法】変更[Correction method] Change

【補正内容】[Correction content]

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

【図１】本発明に係る投影露光装置の一実施例を示す構
成図FIG. 1 is a configuration diagram showing an embodiment of a projection exposure apparatus according to the present invention.

【図２】前記実施例の動作シーケンスを説明するための
フロ−チャートFIG. 2 is a flow chart for explaining the operation sequence of the above embodiment.

【図３】前記実施例の動作概念図FIG. 3 is a conceptual diagram of the operation of the embodiment.

【図４】前記実施例の動作を示すタイミング図FIG. 4 is a timing chart showing the operation of the embodiment.

【図５】本発明の作用を説明するための曲線図FIG. 5 is a curve diagram for explaining the operation of the present invention.

【符号の説明】 ４…Ｚステージ ６…Ｚセンサ ７…計算機 ８…露光シャッター制御系 １０…Ｚ制御系 １１…多重結像露光制御系[Explanation of Codes] 4 ... Z stage 6 ... Z sensor 7 ... Calculator 8 ... Exposure shutter control system 10 ... Z control system 11 ... Multiple imaging exposure control system

───────────────────────────────────────────────────── フロントページの続き (72)発明者 田中 稔彦 東京都国分寺市東恋ケ窪一丁目280番地 株式会社日立製作所中央研究所内 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Toshihiko Tanaka 1-280, Higashi Koikekubo, Kokubunji, Tokyo Inside the Central Research Laboratory, Hitachi, Ltd.

Claims (3)

【特許請求の範囲】[Claims] 【請求項１】光学系の光軸方向における基板表面からの
距離が互いに異なる複数の位置に同一のマスクパターン
像を繰り返して投影露光するための制御手段を具備し、
当該制御手段は、投影露光中、光軸方向に基板を振動さ
せることなしに投影露光を行なうことにより、マスクパ
ターンの結像面を上記複数の位置にそれぞれ形成するも
のであり、かつ、上記複数の位置を予め記憶するための
手段を具備することを特徴とする投影露光装置。1. A control means for repeatedly projecting and exposing the same mask pattern image at a plurality of positions having different distances from the substrate surface in the optical axis direction of the optical system,
The control means forms the image plane of the mask pattern at each of the plurality of positions by performing the projection exposure without vibrating the substrate in the optical axis direction during the projection exposure. A projection exposure apparatus comprising means for pre-storing the position of the. 【請求項２】前記制御手段は、前記複数の位置における
露光量を予め記憶するための手段を更に具備することを
特徴とする請求項１に記載の投影露光装置。2. The projection exposure apparatus according to claim 1, wherein the control means further comprises means for pre-storing exposure amounts at the plurality of positions. 【請求項３】前記制御手段は、前記複数の位置の数を予
め記憶する手段を更に具備することを特徴とする請求項
１又は請求項２に記載の投影露光装置。3. The projection exposure apparatus according to claim 1, wherein the control means further comprises means for storing the number of the plurality of positions in advance.
JP5288329A 1993-11-17 1993-11-17 Projection exposure equipment Expired - Fee Related JP2654418B2 (en)

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Related Parent Applications (1)

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JP61207835A Division JPH0810666B2 (en) 1986-08-08 1986-09-05 Pattern formation method

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2007133382A (en) * 2005-10-05 2007-05-31 Asml Netherlands Bv System and method to correct for field curvature of multilens array

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2009065061A (en) 2007-09-07 2009-03-26 Canon Inc Exposure system, method of exposure, and method of manufacturing device

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4239790A (en) * 1979-09-12 1980-12-16 Rca Corporation Method of defining a photoresist layer
JPS5817446A (en) * 1981-07-24 1983-02-01 Hitachi Ltd Projection exposing method and its device

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4239790A (en) * 1979-09-12 1980-12-16 Rca Corporation Method of defining a photoresist layer
JPS5817446A (en) * 1981-07-24 1983-02-01 Hitachi Ltd Projection exposing method and its device

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2007133382A (en) * 2005-10-05 2007-05-31 Asml Netherlands Bv System and method to correct for field curvature of multilens array
JP4509990B2 (en) * 2005-10-05 2010-07-21 エーエスエムエル ネザーランズ ビー．ブイ． System and method for correcting field curvature in a multi-lens array

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