JPH05109601A - Aligner and exposure method - Google Patents
Aligner and exposure methodInfo
- Publication number
- JPH05109601A JPH05109601A JP29392091A JP29392091A JPH05109601A JP H05109601 A JPH05109601 A JP H05109601A JP 29392091 A JP29392091 A JP 29392091A JP 29392091 A JP29392091 A JP 29392091A JP H05109601 A JPH05109601 A JP H05109601A
- Authority
- JP
- Japan
- Prior art keywords
- light
- pattern
- photomask
- mask
- image
- 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
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
- G03F7/70058—Mask illumination systems
-
- 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
- G03F7/70483—Information management; Active and passive control; Testing; Wafer monitoring, e.g. pattern monitoring
- G03F7/7055—Exposure light control in all parts of the microlithographic apparatus, e.g. pulse length control or light interruption
- G03F7/70566—Polarisation control
Landscapes
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Exposure Of Semiconductors, Excluding Electron Or Ion Beam Exposure (AREA)
- Preparing Plates And Mask In Photomechanical Process (AREA)
- Exposure And Positioning Against Photoresist Photosensitive Materials (AREA)
Abstract
Description
【０００１】[0001]
【産業上の利用分野】本発明は、半導体集積回路パター
ン等の微細パターンの露光転写技術に関するものであ
る。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a technique for exposing and transferring a fine pattern such as a semiconductor integrated circuit pattern.
【０００２】[0002]
【従来の技術】半導体集積回路パターン等の微細パター
ンをレジストが塗布されたウエハ等の感応基板に露光転
写するためには、従来、フォトマスク（レチクルとも言
う）を透過照明して、ウエハ面にマスクパターンを投影
する方法が行なわれてきた。この際、従来の露光方法で
は、照明光の偏光状態を積極的に制御するということは
行なわれておらず、干渉性の強いレーザ光源を使用する
場合に、スペックルを低減する目的で直線偏光を円偏光
やランダム偏光に変換するということがなされている程
度であった。2. Description of the Related Art In order to transfer a fine pattern such as a semiconductor integrated circuit pattern onto a sensitive substrate such as a resist-coated wafer by exposure, a photomask (also referred to as a reticle) is conventionally transmitted and illuminated onto the wafer surface. Methods have been implemented for projecting mask patterns. At this time, in the conventional exposure method, the polarization state of the illumination light is not positively controlled, and when a laser light source with strong coherence is used, linearly polarized light is used for the purpose of reducing speckle. Was converted to circularly polarized light or random polarized light.
【０００３】また、最近では、フォトマスクと感応基板
（ウエハ等）の間に投影光学系を介在させ、マスクパタ
ーンをウエハ面に結像投影（特に縮小投影）する方法が
一般的となっているが、この場合も照明光の偏光状態を
パターン応じて積極的に制御するということは行なわれ
ていない。In recent years, a method of interposing a projection optical system between a photomask and a sensitive substrate (wafer or the like) to project an image of the mask pattern on the wafer surface (in particular, reduction projection) has become common. However, even in this case, the polarization state of the illumination light is not actively controlled according to the pattern.
【０００４】一方、微細パターンの転写に適したフォト
マスクとして、光透過部の一部に透過光の位相を変化さ
せる位相部材を付加した位相シフトマスクが知られてい
る。この位相シフトマスクを使用すると、一般的な露光
装置であっても解像度や焦点深度が向上する。On the other hand, as a photomask suitable for transferring a fine pattern, a phase shift mask in which a phase member for changing the phase of transmitted light is added to a part of a light transmitting portion is known. The use of this phase shift mask improves the resolution and the depth of focus even in a general exposure apparatus.
【０００５】例えば、投影露光装置を使用し、投影光学
系のウエハ側開口数がＮＡｗ、露光波長がλであるとす
ると、位相シフトマスクにより原理的には０．５λ／Ｎ
Ａｗの微細なピッチのパターンまで解像可能であるとさ
れている。For example, if a projection exposure apparatus is used, and the numerical aperture on the wafer side of the projection optical system is NAw and the exposure wavelength is λ, then 0.5 λ / N in principle due to the phase shift mask.
It is said that even a fine pitch pattern of Aw can be resolved.
【０００６】[0006]
【発明が解決しようとする課題】しかしながら、上述し
たような投影露光装置と位相シフトマスクを用いたとし
ても、実際の解像度（実際にレジストパターンを分離す
る解像度）は、原理上の解像度程高くない。However, even if the projection exposure apparatus and the phase shift mask as described above are used, the actual resolution (the resolution for actually separating the resist pattern) is not as high as the theoretical resolution. .
【０００７】この原因の１つとしては、ウエハ面に塗布
されるレジストには厚みがあるため、レジスト層を解像
するには最低限その厚み分だけの焦点深度が必要なこと
が挙げられ、この点については種々の検討がなされてい
る。One of the causes for this is that the resist applied to the wafer surface has a thickness, and therefore, in order to resolve the resist layer, a depth of focus of at least that thickness is required. Various studies have been made on this point.
【０００８】しかし、従来の露光装置では、上記の焦点
深度の問題の他に、照明光の偏光状態が不適当（詳細後
述）であるために像のコントラストが低下するという本
質的な問題がある。特に開口数（ＮＡ）の大きな投影露
光装置、或いはコンタクト型、またはプロキシミティー
型の装置ではこの問題はきわめて重大となる。However, in the conventional exposure apparatus, in addition to the problem of the depth of focus described above, there is an essential problem that the contrast of the image is lowered because the polarization state of the illumination light is inappropriate (details will be described later). . This problem becomes extremely serious particularly in a projection exposure apparatus having a large numerical aperture (NA), a contact type apparatus, or a proximity type apparatus.
【０００９】この発明は、かかる点に鑑みてなされたも
のであり、これまで検討されてこなかった照明光の偏光
状態に着眼することによって、微細パターンの高コント
ラストの像を得ることのできる露光装置及び露光方法を
提供することを目的とするものである。The present invention has been made in view of the above points, and an exposure apparatus capable of obtaining a high-contrast image of a fine pattern by focusing on the polarization state of the illumination light, which has not been studied so far. And an exposure method.
【００１０】[0010]
【課題を解決するための手段】請求項１の発明による露
光装置は、フォトマスクを照明するための照明光学系を
有し、上記の課題を達成するために、前記フォトマスク
への照明光束の偏光状態を制御する偏光部材を備えたも
のである。An exposure apparatus according to a first aspect of the present invention has an illumination optical system for illuminating a photomask, and in order to achieve the above object, an exposure light flux for the photomask is provided. It is provided with a polarizing member for controlling the polarization state.
【００１１】また、請求項３の発明による露光方法は、
フォトマスクを照明することにより、フォトマスクに形
成されたパターンを感応基板上に露光転写するに際し
て、上記の課題を達成するために、前記フォトマスクへ
の照明光の偏光状態を、前記パターンに応じて制御する
ものである。The exposure method according to the invention of claim 3 is
When the pattern formed on the photomask is exposed and transferred onto the sensitive substrate by illuminating the photomask, the polarization state of the illumination light to the photomask is changed according to the pattern in order to achieve the above object. Control it.
【００１２】[0012]
【作用】図３を参照して、本発明の作用を説明する。図
３(A) は、一次元方向に並んだラインアンドスペースパ
ターンを有するマスクの平面図であり、図３(B) は(A)
のマスクに対してほぼ垂直に照明光Ｌｉが入射し、かつ
投影光学系１３によってその像がウエハ１４に結像され
る様子を示す光路図である。The operation of the present invention will be described with reference to FIG. FIG. 3 (A) is a plan view of a mask having line-and-space patterns arranged in one-dimensional direction, and FIG. 3 (B) is (A).
FIG. 9 is an optical path diagram showing a state in which illumination light Li is incident on the mask of FIG. 10 substantially perpendicularly and an image thereof is formed on a wafer 14 by a projection optical system 13.
【００１３】ここで、図３(A) に示されたマスク１１
は、透過光の位相を（２ｍ＋１）π（ｍは整数）だけ変
化させる位相部材１２ａが一定のピッチで配列された空
間周波数変調型の位相シフトマスク（例えば特公昭６２
−５０８１１号公報に開示されている）あるとすると、
位相部材１２ａの被着部と非被着部をそれぞれ透過した
零次回折光同志は相殺されるので、図３(B) においてマ
スクパターン１２より発生する回折光は主として＋１次
回折光Ｄp と−１次回折光Ｄm になる。これら２光束は
投影光学系１３により集光されウエハ１４に至り、ここ
に干渉縞を形成する。この干渉縞が図３(C) ，(D) に示
すマスクパターン１２の像１５ａ，１５ｂ（図では強度
分布として示されている）である。Here, the mask 11 shown in FIG.
Is a spatial frequency modulation type phase shift mask in which phase members 12a for changing the phase of transmitted light by (2m + 1) π (m is an integer) are arranged at a constant pitch (for example, Japanese Patent Publication No.
(Disclosed in Japanese Patent Laid-Open No. 50811),
Since the zero-order diffracted lights that have passed through the adhered part and the non-adhered part of the phase member 12a are canceled out, the diffracted lights generated from the mask pattern 12 in FIG. 3B are mainly + first-order diffracted lights D p and -1. It becomes the next diffracted light D m . These two light fluxes are condensed by the projection optical system 13 and reach the wafer 14, where interference fringes are formed. The interference fringes are the images 15a and 15b of the mask pattern 12 shown in FIGS. 3C and 3D (shown as intensity distribution in the figure).
【００１４】このとき照明光Ｌｉの偏光方向について考
える。図３(C) は照明光Ｌｉの偏光方向（電場ベクトル
の向き）が紙面に垂直、即ちパターン１２の長手方向と
平行である場合（いわゆるＳ偏光）の結像の様子を示す
概念図である。この場合、フォトマスクのパターン面か
ら発生する各回折光（±１次回折光Ｄp ，Ｄm ）の偏光
方向もやはり紙面に垂直となる。ウエハ１４上において
はこの２本の回折光Ｄp ，Ｄm が振幅加算（コヒーレン
ス加算）される。At this time, the polarization direction of the illumination light Li will be considered. FIG. 3C is a conceptual diagram showing a state of image formation when the polarization direction (direction of electric field vector) of the illumination light Li is perpendicular to the paper surface, that is, parallel to the longitudinal direction of the pattern 12 (so-called S-polarized light). .. In this case, the polarization direction of each diffracted light (± first-order diffracted light D p , D m ) generated from the pattern surface of the photomask is also perpendicular to the paper surface. On the wafer 14, the two diffracted lights D p and D m are amplitude-added (coherence addition).
【００１５】図３(C) では＋１次光Ｄp 、−１次光Ｄm
の電場ベクトルの向きは平行であるため、両者の向きが
等しく、かつ大きさを１とすれば、その和の大きさは
２、向きが逆であれば、その和の大きさは０となる。従
って、ウエハ上では強度として、４（＝｜２｜2 あるい
は｜−２｜2 ）の最大値と、０（＝｜０｜2 ）の最小値
からなるコントラスト１００％の像１５ａが形成される
ことになる。In FIG. 3C, the + 1st order light D p and the −1st order light D m
Since the directions of the electric field vectors of are parallel, if both directions are equal and the magnitude is 1, the magnitude of the sum is 2, and if the directions are opposite, the magnitude of the sum is 0. .. Therefore, on the wafer, as the intensity, an image 15a having a contrast of 100% having a maximum value of 4 (= | 2 | 2 or | −2 | 2 ) and a minimum value of 0 (= | 0 | 2 ) is formed. It will be.
【００１６】一方、図３(D) は照明光Ｌｉの偏光方向が
紙面に平行な場合（Ｐ偏光）であって、従って±１次回
折光Ｄp ，Ｄm の偏光面も紙面に平行である。この場合
にもウエハ１４上において、±１次回折光Ｄp ，Ｄm は
振幅加算されるが、両者の偏光方向が平行でないため
（入射角θの倍だけ平行からずれる）、Ｓ偏光による結
像の場合（図３(C) ）とは異なった干渉を起こす。図３
(D) における振幅和の絶対値の最大は２ｃｏｓθ、最小
は２ｓｉｎθとなる。On the other hand, FIG. 3D shows the case where the polarization direction of the illumination light Li is parallel to the paper surface (P polarized light), and therefore the polarization planes of the ± first-order diffracted lights D p and D m are also parallel to the paper surface. . In this case as well, the amplitudes of the ± 1st-order diffracted lights D p and D m are added on the wafer 14, but the polarization directions of the two are not parallel (shifted from the parallel by twice the incident angle θ), and thus the image is formed by S-polarized light. In the case of (Fig. 3 (C)), different interference occurs. Figure 3
The maximum absolute value of the amplitude sum in (D) is 2 cos θ, and the minimum is 2 sin θ.
【００１７】従って、強度の最大は４ｃｏｓ2 θ、最小
は４ｓｉｎ2 θとなり、図３(C) の場合よりコントラス
トの低い干渉縞１５ｂが生じる。例えば、ウエハ１４面
への入射角θが３０°であれば、最大強度は４×（３
1/2 ／２）2 ＝３、最小強度は４×（０．５）2 ＝１と
なり、コントラストは（３−１）／（３＋１）＝５０％
しかない。Therefore, the maximum intensity is 4 cos 2 θ and the minimum intensity is 4 sin 2 θ, and the interference fringes 15b having a lower contrast than in the case of FIG. 3C are generated. For example, if the incident angle θ on the surface of the wafer 14 is 30 °, the maximum intensity is 4 × (3
1/2/2 ) 2 = 3, minimum intensity is 4 × (0.5) 2 = 1 and contrast is (3-1) / (3 + 1) = 50%
There is nothing.
【００１８】実際の露光においては、フォトレジスト中
の光量が問題となり、レジスト中の±１次回折光Ｄp ，
Ｄm の傾きθ’は、ｓｉｎθ’＝ｓｉｎθ／ｎ（ｎはレ
ジストの屈折率）となるので、レジストの屈折率ｎが
１．６であれば、ｓｉｎθ’＝０．３１２５，ｃｏｓ
θ’＝０．９４９９（入射角θ＝３０°）となる。この
とき、強度の最大は４×ｃｏｓ2 θ’＝３．６０９，最
小は４×ｓｉｎ2 θ’＝０．３９１であり、コントラス
トは、（３．６０９−０．３９１）／（３．６０９＋
０．３９１）＝８０％である。In actual exposure, the amount of light in the photoresist becomes a problem, and the ± first-order diffracted light D p in the resist,
Since the slope θ ′ of D m is sin θ ′ = sin θ / n (n is the refractive index of the resist), if the refractive index n of the resist is 1.6, sin θ ′ = 0.3125, cos
θ ′ = 0.9499 (incident angle θ = 30 °). At this time, the maximum intensity is 4 × cos 2 θ ′ = 3.609, the minimum is 4 × sin 2 θ ′ = 0.391, and the contrast is (3.609−0.391) / (3.609+).
0.391) = 80%.
【００１９】一方、図３(C) のＳ偏光による結像の場
合、当然レジスト中においても像のコントラストは１０
０％である。On the other hand, in the case of image formation by S-polarized light in FIG. 3C, the image contrast is naturally 10 even in the resist.
It is 0%.
【００２０】従って、マスクに形成されたパターンがラ
インアンドスペースパターンのとき、パターンの長手方
向と平行な方向に照明光の偏光方向（電場ベクトル）を
揃えることで、より高い像コントラストが得られること
になる。従来使用されている露光装置では、Ｓ偏光とＰ
偏光の平均状態で結像されるが、照明光をパターンに応
じて制御することで、像のコントラストを向上させるこ
とが可能となる。Therefore, when the pattern formed on the mask is a line-and-space pattern, a higher image contrast can be obtained by aligning the polarization direction (electric field vector) of the illumination light in a direction parallel to the longitudinal direction of the pattern. become. In the conventional exposure apparatus, S-polarized light and P-polarized light are used.
Although the image is formed in the average polarization state, the contrast of the image can be improved by controlling the illumination light according to the pattern.
【００２１】図３ではフォトマスクとして位置シフトマ
スクを使用したが、クロム等からなる遮光部材だけでパ
ターン形成された通常マスクであっても上述した作用は
同様であり、照明光の偏光方向をパターンの長手方向と
平行な方向に揃えることで、像のコントラストが高ま
る。また、投影光学系による結像投影を行なう場合だけ
でなく、プロキシミティー方式の露光装置であっても同
様にコントラストの向上が図られる。Although the position shift mask is used as the photomask in FIG. 3, the above-described operation is the same even in the case of a normal mask in which a pattern is formed only by a light shielding member made of chromium or the like, and the polarization direction of the illumination light is patterned. By aligning in a direction parallel to the longitudinal direction of, the image contrast is enhanced. Further, not only when the image projection is performed by the projection optical system, but also in the proximity type exposure apparatus, the contrast is similarly improved.
【００２２】そして、照明光の偏光方向を制御すること
による効果は、どのような形式の露光装置であっても、
ウエハ上に転写すべきパターンが微細である程大きい。
このことは、例えば図３の例において図中のθがパター
ンの微細化と共に大きくなり、Ｐ偏光による結像では、
θ（実際にはθ’）が４５°になると、ｓｉｎ2 θ＝ｃ
ｏｓ2 θとなってコントラストが０となることを考えれ
ば明白である。The effect of controlling the polarization direction of the illumination light can be obtained by any type of exposure apparatus.
The finer the pattern to be transferred onto the wafer, the larger.
This means that, for example, in the example of FIG. 3, θ in the figure becomes larger as the pattern becomes finer, and in imaging by P-polarized light,
When θ (actually θ ′) becomes 45 °, sin 2 θ = c
It is obvious when considering that the contrast becomes os 2 θ and the contrast becomes 0.
【００２３】なお、投影露光装置においてＳ偏光による
結像を行なうためには、投影光学系のフーリエ変換面に
偏光部材を配置してマスクを透過した光の偏光状態を制
御することも考えられるが、照明光がＳ偏光とＰ偏光の
平均状態である場合、偏光部材は照明光の１／２の光量
を吸収することになり、偏光部材の吸熱による結像性能
への影響が問題となる。このため、本発明ではマスク透
過後の光束ではなく、照明光の偏光状態を制御するもの
としている。In order to form an image with S-polarized light in the projection exposure apparatus, it is possible to arrange a polarizing member on the Fourier transform plane of the projection optical system to control the polarization state of the light transmitted through the mask. When the illumination light is in an average state of S-polarized light and P-polarized light, the polarizing member absorbs half the amount of the illumination light, and the heat absorption of the polarizing member affects the imaging performance. Therefore, in the present invention, the polarization state of the illumination light is controlled, not the light flux after passing through the mask.
【００２４】[0024]
【実施例】図１は本発明の実施例による露光装置の構成
図であり、本実施例では照明光学系中に偏光板６を設け
ている。図において、水銀ランプ等の光源１より放射さ
れた照明光は楕円鏡２、ミラー３、集光レンズ４、オプ
チカルインテグレーター５を介して、偏光板６に入射す
る。この偏光板６は支持具７により支持され、かつ、光
軸Ａx あるいは、それと平行な軸を中心として回転可能
となっている。この回転は支持具７上に設けられたモー
ター（不図示）等により行なう。従って偏光板６を透過
する照明光束は、この偏光板６の回転方向に応じた偏光
方向（直線偏光）の光束となる。1 is a block diagram of an exposure apparatus according to an embodiment of the present invention. In this embodiment, a polarizing plate 6 is provided in an illumination optical system. In the figure, illumination light emitted from a light source 1 such as a mercury lamp enters a polarizing plate 6 via an elliptical mirror 2, a mirror 3, a condenser lens 4 and an optical integrator 5. The polarizing plate 6 is supported by a support 7 and is rotatable about an optical axis A x or an axis parallel to the optical axis A x . This rotation is performed by a motor (not shown) provided on the support 7. Therefore, the illumination light beam that passes through the polarizing plate 6 becomes a light beam having a polarization direction (linearly polarized light) according to the rotation direction of the polarizing plate 6.
【００２５】偏光板６を通過した光束は、コンデンサー
レンズ８，１０、ミラー９に導かれてフォトマスク（レ
チクル）１１上の（下面の）パターン１２を照明する。
フォトマスク１１からの透過、回折光は投影光学系１３
により集光、結像され、ウエハ１４にマスクパターン１
２の像を結ぶ。この際、図１中のミラー９が照明光の振
動方向に対して垂直又は平行となる位置からずれると、
直線偏光が楕円偏光に変換されることになるので、この
点に留意する必要がある。The light flux passing through the polarizing plate 6 is guided to condenser lenses 8 and 10 and a mirror 9 to illuminate a pattern 12 (on the lower surface) on a photomask (reticle) 11.
The transmitted and diffracted light from the photomask 11 is projected by the projection optical system 13.
Is focused and imaged by the mask pattern 1 on the wafer 14.
Connect the two images. At this time, if the mirror 9 in FIG. 1 is displaced from the position perpendicular or parallel to the vibration direction of the illumination light,
This point needs to be noted because linearly polarized light will be converted to elliptically polarized light.
【００２６】ここで、マスクパターン１２は図示の如
く、１次元のラインアンドハペースパターンとした。実
際の半導体集積回路パターンにおいては、すべてのパタ
ーンが一次元ラインアンドスペースパターンで、かつ方
向性も等しいということはないが、例えばメモリー回路
の場合、微細なパターンはほぼ一次元のラインアンドス
ペースパターンであり、かつその方向性も１枚のマスク
中においてはほぼ等しいものである。また、一次元ライ
ンアンドスペースパターン以外のパターンの寸法は、ラ
インアンドスペースパターンに比べて大きくなってい
る。Here, the mask pattern 12 is a one-dimensional line and space pattern as shown in the figure. In an actual semiconductor integrated circuit pattern, all patterns are not one-dimensional line-and-space patterns and have the same directionality. For example, in the case of a memory circuit, a fine pattern is almost a one-dimensional line-and-space pattern. And the directionality thereof is almost the same in one mask. The dimensions of the patterns other than the one-dimensional line and space pattern are larger than those of the line and space pattern.
【００２７】従って、偏光板６によって照明光の偏光方
向をマスクパターン１２の長手方向と平行に揃えること
により、微細なラインアンドスペースパターン像のコン
トラストを向上することができ、集積回路の微細化が可
能になる。微細な一次元ラインアンドスペースパターン
以外では、パターンの微細度が比較的ゆるいため、パタ
ーンに対して照明光の偏光が正確に最適化されていなく
ても、生じるコントラストの低下はわずかである。Therefore, by aligning the polarization direction of the illumination light in parallel with the longitudinal direction of the mask pattern 12 by the polarizing plate 6, it is possible to improve the contrast of a fine line and space pattern image and miniaturize the integrated circuit. It will be possible. Except for the fine one-dimensional line-and-space pattern, the fineness of the pattern is relatively low, and therefore, even if the polarization of the illumination light is not accurately optimized with respect to the pattern, the decrease in contrast is slight.
【００２８】ここで、図１においては、光源１は水銀ラ
ンプとしたが、他のランプやレーザー光源であっても良
い。特に光源が直線偏光または円偏光を射出するレーザ
である場合は、偏光状態を制御するための部材として１
／２波長板や１／４波長板を用いることができる。Although the light source 1 is a mercury lamp in FIG. 1, it may be another lamp or a laser light source. In particular, when the light source is a laser that emits linearly polarized light or circularly polarized light, 1 is used as a member for controlling the polarization state.
A half wave plate or a quarter wave plate can be used.
【００２９】図２(A) は光源としてレーザを用いる場合
の偏光部材の例を示す説明図である。図において、直線
偏光（偏光方向は紙面上下方向）である入射光Ｌ0 （光
源からの光束）は、１／２波長板６ａに入射する。この
とき１／２波長板６ａの基準軸方向（図中２点鎖線）
と、入射光Ｌ0 の偏光方向がθだけ傾いているものとす
る。この結果、射出光Ｌ1 の偏光方向は、入射光Ｌ0 の
偏光方向に対して２θだけ傾いたものとなる。従って、
保持具７により１／２波長板６ａを照明光に垂直な面内
で回転することにより、射出光Ｌ1 の偏光方向を任意の
方向に設定することができる。FIG. 2A is an explanatory view showing an example of a polarizing member when a laser is used as a light source. In the figure, incident light L 0 (light flux from the light source) that is linearly polarized light (the polarization direction is the vertical direction on the paper surface) is incident on the ½ wavelength plate 6 a. At this time, the reference axis direction of the half-wave plate 6a (two-dot chain line in the figure)
Then, it is assumed that the polarization direction of the incident light L 0 is inclined by θ. As a result, the polarization direction of the emitted light L 1 is inclined by 2θ with respect to the polarization direction of the incident light L 0 . Therefore,
By rotating the half-wave plate 6a in the plane perpendicular to the illumination light by the holder 7, the polarization direction of the emitted light L 1 can be set to an arbitrary direction.
【００３０】なお、１／２波長板６ａの基準軸は、図２
(B) に示される如く、基準軸（２点鎖線）に平行な偏光
方向の透過光に対しては、ｌ1 ＝ｍλ＋αの光路長差を
与え、垂直な偏光方向の透過光に対しては、ｌ2 ＝ｍλ
＋α＋λ／２＝ｌ1 ＋λ／２の光路長を与える軸とし
た。The reference axis of the half-wave plate 6a is shown in FIG.
As shown in (B), the optical path length difference of l 1 = mλ + α is given to the transmitted light in the polarization direction parallel to the reference axis (two-dot chain line), and the transmitted light in the vertical polarization direction is given. , L 2 = mλ
The axis giving an optical path length of + α + λ / 2 = l 1 + λ / 2.
【００３１】光源から放射される光が直線偏光でなく円
偏光である場合は、１／２波長板の代わりに１／４波長
板を使うことにより、図２で説明したと同様にして射出
光の偏光方向を制御することができる。この場合、射出
される光束は、１／４波長板の回転位置方向に応じた直
線偏光となる。When the light emitted from the light source is circularly polarized light rather than linearly polarized light, the quarter wave plate is used instead of the half wave plate, and the emitted light is the same as described with reference to FIG. The polarization direction of can be controlled. In this case, the emitted light beam becomes linearly polarized light according to the rotational position direction of the quarter-wave plate.
【００３２】上記のように、光源として直線偏光または
円偏光を射出するレーザを用い、偏光部材として１／２
波長板や１／４波長板を用いれば、光源からの光量を損
失することなく偏光方向を最適な方向に変換してマスク
に導くことができる。これに対し、光源としてランプを
用いた場合（非偏光状態の光が光源から放射される場
合）、偏光部材通過後の光量は原理的に半分になってし
まうので、この点に留意する必要がある。As described above, a laser that emits linearly polarized light or circularly polarized light is used as the light source, and 1/2 is used as the polarizing member.
If a wave plate or a quarter wave plate is used, the polarization direction can be converted to an optimum direction and guided to the mask without loss of the light amount from the light source. On the other hand, when a lamp is used as the light source (when light in the non-polarized state is emitted from the light source), the amount of light after passing through the polarizing member is theoretically halved, so it is necessary to pay attention to this point. is there.
【００３３】なお、偏光部材として１／４波長板，１／
２波長板を使用する場合、入射光束は平行光束に近いこ
とが望ましい。従って、１／４波長板，１／２波長板は
図１中のオプチカルインテグレーター５射出後でなく、
例えばリレーレンズ４より光源（レーザ光源）側に設定
することが好ましい。この配置は、水銀ランプ等の光源
を用いる場合に対して適用してもかまわない。As a polarizing member, a 1/4 wavelength plate, 1 /
When a two-wave plate is used, it is desirable that the incident light flux be close to a parallel light flux. Therefore, the quarter-wave plate and the half-wave plate are not after the injection of the optical integrator 5 in FIG.
For example, it is preferable to set it on the light source (laser light source) side of the relay lens 4. This arrangement may be applied to the case where a light source such as a mercury lamp is used.
【００３４】[0034]
【発明の効果】以上にように本発明においては、マスク
パターン、特に微細な一次元ラインアンドスペースパタ
ーンに応じて照明光の偏光状態を制御するので、パター
ン形成面からの回折光の干渉性が高まり、感応基板上に
極めて高いコントラストの微細パターンの像を転写する
ことが可能となる。この際、位相シフトマスクを使用す
れば、一層像のコントラストを高めることができる。ま
た、照明光の偏光状態を制御するに際して、偏光部材と
して１／２または１／４波長板を使用し、光源としてレ
ーザを使用すれば照明光量を損失することもない。As described above, in the present invention, since the polarization state of the illumination light is controlled according to the mask pattern, particularly the fine one-dimensional line-and-space pattern, the coherence of the diffracted light from the pattern formation surface is As a result, it becomes possible to transfer an image of a fine pattern with extremely high contrast onto the sensitive substrate. At this time, if a phase shift mask is used, the contrast of the image can be further enhanced. Further, when controlling the polarization state of the illumination light, if a 1/2 or 1/4 wavelength plate is used as the polarization member and a laser is used as the light source, the amount of illumination light will not be lost.
【図１】本発明実施例による露光装置の構成図である。FIG. 1 is a configuration diagram of an exposure apparatus according to an embodiment of the present invention.
【図２】(A) ，(B) は光源にレーザを用いる場合の偏光
部材について説明するための外面図である。2A and 2B are external views for explaining a polarizing member when a laser is used as a light source.
【図３】(A) 〜(D) は本発明の作用を説明するための概
念図である。FIGS. 3A to 3D are conceptual diagrams for explaining the operation of the present invention.
１ 光源 ２ 楕円鏡 ３，９ ミラー ４ 集光レンズ ５ オプチカルインテグレータ ６ 偏光板 ６ａ １／２波長板 ７ 支持具 ８，１０ コンデンサーレンズ １１ フォトマスク（レチクル） １３ 投影光学系 １４ ウエハ DESCRIPTION OF SYMBOLS 1 Light source 2 Elliptical mirror 3,9 Mirror 4 Condensing lens 5 Optical integrator 6 Polarizing plate 6a 1/2 wavelength plate 7 Support tool 8,10 Condenser lens 11 Photomask (reticle) 13 Projection optical system 14 Wafer
───────────────────────────────────────────────────── フロントページの続き (51)Int.Cl.5 識別記号 庁内整理番号 ＦＩ 技術表示箇所 7352−4Ｍ Ｈ０１Ｌ 21/30 ３１１ Ｗ ─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. 5 Identification code Office reference number FI technical display location 7352-4M H01L 21/30 311 W
Claims (4)
する露光装置において、前記フォトマスクへの照明光束
の偏光状態を制御する偏光部材を備えたことを特徴とす
る露光装置。1. An exposure apparatus having an illumination optical system for illuminating a photomask, the exposure apparatus comprising a polarizing member for controlling a polarization state of an illumination light beam to the photomask.
４波長板により構成されることを特徴とする請求項１の
露光装置。2. The polarizing member is a half-wave plate or a one-half wave plate.
The exposure apparatus according to claim 1, wherein the exposure apparatus comprises a four-wave plate.
記フォトマスクに形成されたパターンを感応基板上に転
写する露光方法において、前記フォトマスクへの照明光
の偏光状態を、前記パターンに応じて制御することを特
徴とする露光方法。3. An exposure method in which a pattern formed on the photomask is transferred onto a sensitive substrate by illuminating the photomask, and a polarization state of illumination light to the photomask is controlled according to the pattern. An exposure method comprising:
光透過部に透過光の位相を変化させる位相部材が付加さ
れた位相シフト部とからなるパターンを有する位相シフ
トマスクを用いることを特徴とする露光方法。4. A phase shift mask having a pattern comprising a light transmitting portion and a phase shift portion having a phase member for changing the phase of transmitted light added to the light transmitting portion is used as the photomask. Exposure method.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP29392091A JPH05109601A (en) | 1991-10-15 | 1991-10-15 | Aligner and exposure method |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP29392091A JPH05109601A (en) | 1991-10-15 | 1991-10-15 | Aligner and exposure method |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH05109601A true JPH05109601A (en) | 1993-04-30 |
Family
ID=17800875
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP29392091A Pending JPH05109601A (en) | 1991-10-15 | 1991-10-15 | Aligner and exposure method |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH05109601A (en) |
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-
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- 1991-10-15 JP JP29392091A patent/JPH05109601A/en active Pending
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