JPH0564450B2 - - Google Patents
Info
- Publication number
- JPH0564450B2 JPH0564450B2 JP59195728A JP19572884A JPH0564450B2 JP H0564450 B2 JPH0564450 B2 JP H0564450B2 JP 59195728 A JP59195728 A JP 59195728A JP 19572884 A JP19572884 A JP 19572884A JP H0564450 B2 JPH0564450 B2 JP H0564450B2
- Authority
- JP
- Japan
- Prior art keywords
- reduction projection
- exposure area
- image
- substrate
- exposure
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Lifetime
Links
- 239000000758 substrate Substances 0.000 claims description 31
- 230000003287 optical effect Effects 0.000 claims description 24
- 238000001514 detection method Methods 0.000 claims description 20
- 238000003384 imaging method Methods 0.000 claims description 18
- 238000000034 method Methods 0.000 claims description 16
- 238000006073 displacement reaction Methods 0.000 claims description 8
- 230000001678 irradiating effect Effects 0.000 claims description 4
- 238000010586 diagram Methods 0.000 description 11
- 229920002120 photoresistant polymer Polymers 0.000 description 4
- 230000010287 polarization Effects 0.000 description 2
- 230000006866 deterioration Effects 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 230000010354 integration Effects 0.000 description 1
- 239000004065 semiconductor Substances 0.000 description 1
Classifications
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
- H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
- H01L21/04—Manufacture or treatment of semiconductor devices or of parts thereof the devices having at least one potential-jump barrier or surface barrier, e.g. PN junction, depletion layer or carrier concentration layer
- H01L21/18—Manufacture or treatment of semiconductor devices or of parts thereof the devices having at least one potential-jump barrier or surface barrier, e.g. PN junction, depletion layer or carrier concentration layer the devices having semiconductor bodies comprising elements of Group IV of the Periodic System or AIIIBV compounds with or without impurities, e.g. doping materials
- H01L21/30—Treatment of semiconductor bodies using processes or apparatus not provided for in groups H01L21/20 - H01L21/26
Description
【発明の詳細な説明】
〔発明の利用分野〕
本発明は、縮小投影レンズの結像面にウエハ等
の被露光基板上の露光領域表面を合わせてマスク
上に形成されたLSI等の回路パターンを縮小投影
レンズにより被露光基板上の露光領域に縮小投影
して露光する縮小投影露光装置及びその方法に関
する。[Detailed Description of the Invention] [Field of Application of the Invention] The present invention relates to a circuit pattern such as an LSI formed on a mask by aligning the image forming plane of a reduction projection lens with the surface of an exposed area on a substrate to be exposed such as a wafer. The present invention relates to a reduction projection exposure apparatus and method for reducing and projecting an image onto an exposure area on a substrate to be exposed using a reduction projection lens.
従来より、半導体ウエハ上のLSIパターンな
ど、被観察物の表面の焦点位置に対する位置ずれ
を検出して位置合せを行なう方法においては、被
観察物表面に断面が例えば３mm×0.1mm程度の細
長い形状をした単一の光束を斜めに照射し、被観
察物表面からのその反射光を光電変換して反射光
の光軸位置を検出している。しかしながらこのよ
うに小さな断面形状の光束を用いて被観察物表面
を検出すると、被観察物の表面形状に凹凸があつ
たり、或いは、表面の反射率が微小な領域内で異
なつていたりすると、その表面状態の影響で正確
な位置検出および位置合せが困難になるという欠
点があつた。
Conventionally, in the method of detecting and aligning the surface of an object to be observed, such as an LSI pattern on a semiconductor wafer, by detecting the positional deviation from the focal point, a long and narrow shape with a cross section of about 3 mm x 0.1 mm is placed on the surface of the object to be observed. A single beam of light is emitted obliquely, and the reflected light from the surface of the object to be observed is photoelectrically converted to detect the optical axis position of the reflected light. However, when detecting the surface of an object to be observed using a light beam with such a small cross-sectional shape, if the surface shape of the object to be observed is uneven or the reflectance of the surface differs within a minute area, The disadvantage is that accurate position detection and alignment are difficult due to the influence of the surface condition.
特開昭56−42205号公報にはその解決策のひと
つとして、被観察物表面上での光束断面の細長い
方向が、被観察物表面の表面形状に影響されない
方向を向くように光束を照射する方法が開示され
ているが、未だ十分な解決策とはなつていないの
が実情であり、検出領域が小さいと、被観察物表
面の反り、うねり、傾きなどの検出が困難で、ま
た被観察物が透光性の場合、その表面で反射する
光束と、内部に進入して下の層との境で反射して
再び出てくる光束とがあるが、これらが混じり合
うと検出光として一様のもとはならず、検出精度
が劣化するという問題も未解決のままである。 JP-A No. 56-42205 discloses one solution to this problem, in which the light beam is irradiated so that the elongated direction of the beam cross section on the surface of the object to be observed is directed in a direction that is not affected by the surface shape of the surface of the object to be observed. Although a method has been disclosed, the reality is that it has not yet become a sufficient solution.If the detection area is small, it is difficult to detect warps, undulations, inclinations, etc. on the surface of the observed object. When an object is translucent, there is a beam of light that is reflected on its surface and a beam of light that enters the interior, reflects at the boundary with the layer below, and comes out again. However, the problem of deterioration of detection accuracy remains unsolved.
本発明の目的は、前述の従来技術の問題点を解
決すべく、ウエハ等の被露光基板上の露光領域表
面の傾きを正確に検出して縮小投影レンズの結像
面に対してウエハ等の被露光基板上の露光領域表
面の傾きを合わせてマスク上に形成された微細な
回路パターンを縮小投影レンズにより被露光基板
上の露光領域に高解像度で縮小投影露光焼き付け
を可能にした縮小投影露光装置およびその方法を
提供することにある。
SUMMARY OF THE INVENTION An object of the present invention is to accurately detect the inclination of the surface of an exposure area on a substrate to be exposed such as a wafer, so as to solve the problems of the prior art described above. Reduction projection exposure enables high-resolution reduction projection exposure printing of a fine circuit pattern formed on a mask onto the exposure area on the exposure target substrate using a reduction projection lens by adjusting the surface inclination of the exposure area on the exposure target substrate. An object of the present invention is to provide a device and a method thereof.
本発明は、上記目的を達成するため、マスク
（レチクル）に形成された回路パターンを縮小投
影レンズにより被露光基板上の露光領域表面に縮
小投影露光する縮小投影露光装置およびその方法
において、前記被露光基板を前記縮小投影レンズ
の光軸方向に微移動させ、更に前記縮小投影レン
ズの結像面に対する前記被露光基板を微回動させ
るステージ手段と、前記縮小投影レンズと前記被
露光基板との間の側方より複数の光束を前記被露
光基板上の露光領域表面の異なる照射位置に縮小
投影レンズの光軸方向に対して70°以上の傾斜角
度で照射する照射手段と、該照射手段で照射され
て露光領域表面の異なる照射位置の各々から反射
する光像を、前記縮小投影レンズと前記被露光基
板との間の側方より検出して少なくとも位置検出
方向について像面に結像させる検出結像光学系
と、該検出結像光学系により像面に結像された露
光領域表面の各照射位置の高さに対応した各光像
の位置を検出して該各照射位置の高さに対応した
信号を出力する少なくとも一次元のイメージセン
サと、該イメージセンサから出力される各照射位
置の高さに対応した信号に基づいて露光領域表面
の前記結像面に対する傾きを算出し、該算出され
た露光領域表面の傾きに基づいて前記ステージ手
段を微回動駆動制御する制御手段とを備えたこと
を特徴とする縮小投影露光装置およびその方法で
ある。また本発明は、上記縮小投影露光装置およ
びその方法において、前記制御手段は、イメージ
センサから出力される各照射位置の高さに対応し
た信号に基づいて露光領域表面の前記結像面に対
する平均的な変位を算出し、該算出された変位に
基づいて前記ステージ手段を縮小投影レンズの光
軸方向に微移動駆動制御する制御手段を有するこ
とを特徴とする。また本発明は、上記縮小投影露
光装置およびその方法において、前記照射手段
は、前記複数の光束を、前記被露光基板上の露光
領域表面の異なる照射位置に対してＳ偏光で照射
するように構成したことを特徴とする。
In order to achieve the above object, the present invention provides a reduction projection exposure apparatus and method for reducing and exposing a circuit pattern formed on a mask (reticle) onto the surface of an exposure area on an exposure target substrate using a reduction projection lens. stage means for slightly moving the exposure substrate in the optical axis direction of the reduction projection lens and further slightly rotating the exposure substrate with respect to the imaging plane of the reduction projection lens; an irradiation means for irradiating a plurality of light beams from the sides between them at different irradiation positions on the surface of the exposure area on the substrate to be exposed at an inclination angle of 70° or more with respect to the optical axis direction of the reduction projection lens; Detecting a light image irradiated and reflected from each of different irradiation positions on the surface of the exposure area from a side between the reduction projection lens and the substrate to be exposed, and forming the image on an image plane at least in the position detection direction. The imaging optical system and the detection imaging optical system detect the position of each light image corresponding to the height of each irradiation position on the surface of the exposure area that is imaged on the image plane, and adjust the height of each irradiation position. Calculating the inclination of the surface of the exposure area with respect to the imaging plane based on the at least one-dimensional image sensor outputting a corresponding signal and the signal corresponding to the height of each irradiation position output from the image sensor; A reduction projection exposure apparatus and a method thereof, characterized in that the apparatus further comprises a control means for controlling the stage means to rotate slightly based on the tilt of the surface of the exposure area. Further, the present invention provides the reduction projection exposure apparatus and method thereof, wherein the control means is configured to adjust the average of the surface of the exposure area relative to the image forming plane based on a signal corresponding to the height of each irradiation position output from the image sensor. The present invention is characterized by comprising a control means that calculates a displacement and controls the stage means to move finely in the optical axis direction of the reduction projection lens based on the calculated displacement. Further, the present invention provides the reduction projection exposure apparatus and method thereof, wherein the irradiation means is configured to irradiate the plurality of light beams with S-polarized light onto different irradiation positions on the surface of the exposure area on the substrate to be exposed. It is characterized by what it did.
以下本発明に係る縮小投影露光装置について図
面を参照して説明する。第１図は本発明に係る縮
小投影露光装置において、縮小レンズ（縮小投影
レンズ）１の焦点位置（結像面）にウエハ２の露
光領域の表面を焦点合わせする光学・機械系を示
す補足説明図である。
DESCRIPTION OF THE PREFERRED EMBODIMENTS A reduction projection exposure apparatus according to the present invention will be described below with reference to the drawings. FIG. 1 is a supplementary explanation showing an optical/mechanical system for focusing the surface of an exposure area of a wafer 2 on the focal position (imaging plane) of a reduction lens (reduction projection lens) 1 in a reduction projection exposure apparatus according to the present invention. It is a diagram.
第１図において、レーザ光源３からのレーザ光
束をビームエキスパンダ４により図の紙面表裏方
向に拡げて偏平な光束にし、スリツト５に入射さ
せる。スリツト５を通過した断面が細長い形状の
光を第１レンズ６を介して第１反射ミラー７に入
射させ、ミラー７で前記光束断面の細長い方向と
直交する方向に光路を曲げて、ウエハ２上に斜め
上方から照射することによりウエハ２上にスリツ
ト５の像５′を投影結像させる。このスリツト像
５′は第２反射ミラー８で光路を曲げて第２レン
ズ９により対物レンズ１０の手前に結像させる。
この位置におけるスリツト像はスリツト５の位置
の像と同形状である。対物レンズ１０はこのスリ
ツト像をさらに拡大するためのものであるが、対
物レンズ１０の視野には限界があるため、スリツ
ト像の長手方向を圧縮するためにこの例では第１
円筒レンズ１１を配置してある。対物レンズ１０
で拡大したスリツト像をCCDの如きリニアイメ
ージセンサ１２上に投影結像させるが、この場合
もセンサ１２の受光部は細幅の窓であるため、第
２円筒レンズ１３を配置し、スリツト像の全てを
圧縮してセンサ１２の受光画素列上に投影結像さ
せている。 In FIG. 1, a laser beam from a laser light source 3 is expanded by a beam expander 4 in the direction of the plane of the drawing to form a flat beam, and the beam is made incident on a slit 5. The light having an elongated cross section that has passed through the slit 5 is incident on the first reflecting mirror 7 via the first lens 6, and the optical path is bent by the mirror 7 in a direction perpendicular to the elongated direction of the cross section of the light beam, and the light is directed onto the wafer 2. An image 5' of the slit 5 is projected onto the wafer 2 by irradiating the slit 5 obliquely from above. The optical path of this slit image 5' is bent by a second reflecting mirror 8, and an image is formed in front of the objective lens 10 by a second lens 9.
The slit image at this position has the same shape as the image at the slit 5 position. The objective lens 10 is for further enlarging this slit image, but since the field of view of the objective lens 10 is limited, in this example, the first lens is used to compress the slit image in the longitudinal direction.
A cylindrical lens 11 is arranged. Objective lens 10
The magnified slit image is projected onto a linear image sensor 12 such as a CCD, but in this case as well, the light receiving part of the sensor 12 is a narrow window, so a second cylindrical lens 13 is placed to capture the slit image. All are compressed and projected onto the light-receiving pixel array of the sensor 12.
第２図は第１図の例においてスリツトが各結像
位置でどの様な形状になるかを示しており、図の
紙面表裏方向に細長い一本のスリツト５の像が、
ウエハ２上では、で示すように幅方向に拡大さ
れたスリツト像５ａとして、投影結像され、対物
レンズ１０の手前では、で示す如く円筒レンズ
１１によつて長手方向が圧縮されたスリツト像
５′ａとして結像され、またリニアイメージセン
サ１２上では、に示すように対物レンズ１０で
拡大されたスリツト像５′ａの長手方向を円筒レ
ンズ１３によつて圧縮したスリツト像５″ａとし
て投影結像されている。 FIG. 2 shows the shape of the slit at each imaging position in the example of FIG.
On the wafer 2, a slit image 5a enlarged in the width direction as shown in is projected and imaged, and in front of the objective lens 10, a slit image 5 compressed in the longitudinal direction by a cylindrical lens 11 as shown in is formed. 'a', and on the linear image sensor 12, the slit image 5'a, which has been enlarged by the objective lens 10 in the longitudinal direction, is compressed by the cylindrical lens 13 and projected as a slit image 5'a. imaged.
第３図にウエハ２上に結像される一本のスリツ
ト像５ａの照射位置の違いによる検出位置の差を
示す。例えばウエハ２の表面形状が第３図に示す
ような凹凸形状となつているものとすると、その
上に塗布されたフオトレジスト１４もその凹凸状
にならつた表面形状になる。このレジスタ１４の
表面を検出する際、スリツト像５ａが小さいと、
実線で示す光束で凹部を検出して縮小レンズ１の
焦点位置に合せ、これによつて露光を行なつた場
合に、表面部（凸部）は焦点位置からずれること
になるので、部分的に解像状態が悪いというよう
な事態が生じる恐れがあり、また逆に一転鎖線で
示す光束で凸部を検出すれば凹部で焦点ずれを起
こすことになる。さらにウエハ２が縮小レンズ１
の光軸に対して傾斜していると、焦点検出位置で
は高解像度で露光できるが、その他の箇所は焦点
ずれを起こし、解像しないという課題が生じる恐
れがある。 FIG. 3 shows the difference in detection position due to the difference in the irradiation position of one slit image 5a formed on the wafer 2. For example, if the surface of the wafer 2 has an uneven shape as shown in FIG. 3, the photoresist 14 applied thereon also has a surface that follows the same unevenness. When detecting the surface of this register 14, if the slit image 5a is small,
When the concave part is detected with the light beam shown by the solid line and aligned with the focal position of the reduction lens 1, and exposure is performed using this, the surface part (convex part) will be shifted from the focal position, so it will be partially There is a possibility that a situation such as poor resolution may occur, and conversely, if a convex portion is detected with the light beam shown by the dashed line, a defocus will occur at the concave portion. Furthermore, the wafer 2 is attached to the reduction lens 1.
If the lens is tilted with respect to the optical axis of the lens, exposure can be performed with high resolution at the focus detection position, but other locations may be out of focus and may not be resolved.
本発明は、上記課題を解決すべく、第４図に示
すように、ウエハ２の表面にスリツト像５ａを複
数同時に投影結像させ、各々のスリツト像の平均
高さを縮小ンズの合焦位置とすることにより前述
の焦点ずれを解消することができる。第５図は本
発明の実施例を示すもので、第１図の装置におい
てスリツト５を複数並べて本発明を適用した場合
の要部の構成を示している。このようにスリツト
５を複数平行に並べた多重スリツト１５を配置す
ると、第１レンズ６によつてウエハ２上の露光領
域にはスリツト５の幅方向が拡大された平行スリ
ツト像５ｂが投影結像される。この平行スリツト
像５ｂは、第２レンズ９で対物レンズの手前にス
リツト長手方向に縮小された像５′ｂとして結像
される。前述と同様に対物レンズ１０により拡大
され第２円筒レンズ１３でスリツト長さ方向に圧
縮されたスリツト像５′ｂは、第６図上部に示す
ようにリニアイメージセンサ１２上に平行なスリ
ツト像５″ｂの列として投影結像され、そのとき
のセンサ１２の出力は第６図下部に示す様にな
る。 In order to solve the above problems, the present invention projects and forms a plurality of slit images 5a on the surface of the wafer 2 at the same time, as shown in FIG. By doing so, the above-mentioned defocus can be eliminated. FIG. 5 shows an embodiment of the present invention, and shows the configuration of essential parts when the present invention is applied to the apparatus shown in FIG. 1 by arranging a plurality of slits 5. When multiple slits 15 in which a plurality of slits 5 are arranged in parallel are arranged in this way, a parallel slit image 5b, in which the width direction of the slits 5 is enlarged, is projected onto the exposure area on the wafer 2 by the first lens 6. be done. This parallel slit image 5b is formed by the second lens 9 in front of the objective lens as an image 5'b reduced in the longitudinal direction of the slit. The slit image 5'b, which has been enlarged by the objective lens 10 and compressed in the longitudinal direction of the slit by the second cylindrical lens 13 in the same way as described above, forms a parallel slit image 5 on the linear image sensor 12, as shown in the upper part of FIG. It is projected and imaged as a column "b", and the output of the sensor 12 at that time is as shown in the lower part of FIG.
ここで一般に縮小投影露光装置における焦点合
せは、試し焼きを行なつて縮小レンズの合焦位置
（結像面の高さ位置）を求めておき、これを基準
位置としてウエハ２を位置決めすることにより行
なわれる。即ち、ウエハ２を微小距離（0.5μｍ程
度）ずつ上下させて試し焼きを行ない、最も解像
状態が良い時のウエハ２の位置をセンサ１２上の
スリツト像５″ｂの位置X1，X2，X3…Xnのデー
タとして、適当な記憶装置に記憶させておく。次
いで新たにセツトしたウエハ２上にスリツト像５
ｂを投影結像し、それによつてセンサ１２上に結
像されるスリツト像５″ｂが前記記憶装置内の位
置データX1，X2，X3…Xnで表わされる位置に来
るようにウエハステージ１６を上下させ、焦点合
せを行なう。尚、スリツト像５″ｂの位置は、第
７図に拡大して示すように、センサ１２の出力に
対して閾値Thを設定し、その閾値に相当するセ
ンサ１２の画素２０を求め、その中央値をスリツ
ト像５″ｂの位置と設定するようにしてもよい。 In general, focusing in a reduction projection exposure apparatus is performed by performing trial printing to determine the focus position (height position of the image plane) of the reduction lens, and then positioning the wafer 2 using this as a reference position. It is done. That is, test printing is performed by moving the wafer 2 up and down by a minute distance (approximately 0.5 μm), and the position of the wafer 2 when the resolution is the best is determined by the positions of the slit image 5''b on the sensor 12, X 1 and X 2 . , X 3 ...
The wafer is projected and imaged so that the slit image 5''b formed on the sensor 12 is located at the position represented by the position data X 1 , X 2 , X 3 . . . Xn in the storage device. Focusing is performed by moving the stage 16 up and down.The position of the slit image 5''b is determined by setting a threshold value Th for the output of the sensor 12, as shown in an enlarged view in FIG. The pixels 20 of the sensor 12 may be determined, and the median value thereof may be set as the position of the slit image 5''b.
第５図の実施例では複数のスリツト５がＸ方向
のみに並んでいたが、第８図はXYの２方向に複
数のスリツト５が並んでいる多重スリツト１７を
用いた実施例をしめしている。この場合、光電変
換器としてはエリアイメージセンサ１７を用い
る。このように、XY方向にスリツト５を設ける
と、ウエハ２の傾きまでも検出し位置合せできる
ようになる。この場合においても前述と同様に縮
小レンズの合焦位置（結像面の高さ位置）を予め
試し焼きによつて求めておき、そのときのエリア
イメージセンサ１７上のスリツト像５″ｃの位置
をメモリーに記憶しておく。このようにすれば、
第９図ａ〜ｄに示すように、ウエハ２に投影結像
されたスリツト像５ｃの位置（これはセンサ１７
上に投影結像されたスリツト像５″ｃの位置と同
等）により、ウエハ２の傾き即ち姿勢も検出する
ことができる。第９図において、ａは合焦位置に
ある時、ｂはＸ方向に上下の傾きがあり、Ｙ方向
について合焦している時、ｃはＸ方向について合
焦しており、Ｙ方向について上下の傾きがある
時、ｄはXY両方向について上下の傾きがある場
合をしめしている。 In the embodiment shown in Fig. 5, a plurality of slits 5 are lined up only in the X direction, but Fig. 8 shows an embodiment using a multiple slit 17 in which a plurality of slits 5 are lined up in two directions, XY. . In this case, the area image sensor 17 is used as the photoelectric converter. By providing the slits 5 in the XY directions in this way, even the inclination of the wafer 2 can be detected and aligned. In this case as well, the focusing position (height position of the imaging surface) of the reduction lens is determined in advance by trial printing in the same manner as described above, and the position of the slit image 5''c on the area image sensor 17 at that time is determined in advance. is stored in memory.In this way,
As shown in FIGS. 9a to 9d, the position of the slit image 5c projected onto the wafer 2 (this is the position of the slit image 5c projected on the wafer 2)
The inclination or posture of the wafer 2 can also be detected from the position of the slit image 5''c projected and formed above. In FIG. 9, a is at the focused position, b is the X direction has a vertical tilt and is focused in the Y direction, c is focused in the X direction and has a vertical tilt in the Y direction, and d indicates a case where there is a vertical tilt in both the X and Y directions. It's showing.
以上のような検出系に加えてウエハを傾き調整
自在なホルダー付きのステージに載置すれば、縮
小レンズの結像面へのウエハの傾き調整ができ、
極めて高精度の焦点検出と焦点合せを実現し得る
ものである。 In addition to the detection system described above, if the wafer is placed on a stage with a holder whose tilt can be adjusted, the tilt of the wafer to the imaging plane of the reduction lens can be adjusted.
This makes it possible to achieve extremely high precision focus detection and focusing.
次にウエハ２上へ照射する光束の入射角と偏光
方向について第１０図と第１１図によつて説明す
る。 Next, the incident angle and polarization direction of the light beam irradiated onto the wafer 2 will be explained with reference to FIGS. 10 and 11.
ウエハ２にフオトレジスタ１４を塗布した場合
の光の進行方向は、第１０図に示すように、レジ
スト１４の表面で反射するものと、レジスタ１４
の中に入り込んで下地層１９で反射して再び出て
くる光、レジスト１４内で反射する光、下地層１
９に入り込む光などがある。レジスト１４表面だ
けで光が反射すれば、リニアイメージセンサ１２
やエリアイメージセンサ１７でそのレジスト表面
の合焦位置検出が可能となる。しかしながら、下
地層１９からの反射光があると、前記センサ上で
はどこの位置を検出しているのか正確に判断でき
ない場合が生じる。そこで出来るだけレジスト１
４表面での反射率を高くする必要があり、このた
め好ましくはウエハ２への光束の入射角を70°以
上に大きくし、また入射光束をＳ偏光とするのが
よい。 When the photoresist 14 is coated on the wafer 2, the traveling direction of the light is as shown in FIG.
Light that enters the inside, reflects on the base layer 19 and comes out again, light that is reflected within the resist 14, base layer 1
There is light that enters 9. If light is reflected only on the surface of the resist 14, the linear image sensor 12
The area image sensor 17 can detect the focused position on the resist surface. However, if there is reflected light from the base layer 19, it may not be possible to accurately determine which position is being detected on the sensor. So resist 1 as much as possible
It is necessary to increase the reflectance on the wafer 4 surface, and for this reason, it is preferable that the angle of incidence of the light beam onto the wafer 2 be made larger than 70°, and that the incident light beam be S-polarized.
以上の述べたように本発明によれば、縮小投影
露光装置およびその方法において、複数の光束を
被露光基板上の露光領域表面の異なる照射位置に
縮小投影レンズの光軸方向に対して70°以上の傾
斜角度で照射し、露光領域表面の異なる照射位置
の各々から反射する光像を少なくとも位置検出方
向について像面に結像させ、像面に結像された露
光領域表面の各照射位置の高さに対応した各光像
の位置を少なくとも一次元のイメージセンサで検
出し、該イメージセンサから出力される各照射位
置の高さに対応した信号に基づいて被露光基板上
の露光領域表面の縮小投影レンズの結像面に対す
る傾きを算出し、該算出された被露光基板表面上
の露光領域の傾きに基づいて被露光基板の傾きを
調整するようにしたので、被露光基板上の露光領
域表面を縮小投影レンズの結像面に高精度に合ら
せることができ、マスク（レチクル）上に形成さ
れた微細な回路パターンを縮小投影レンズにより
被露光基板上の露光領域に高解像度で縮小投影露
光焼き付けを可能にして、LSI製品歩留りの一層
の向上と高集積化とをはかることができる効果を
奏する。
As described above, according to the present invention, in the reduction projection exposure apparatus and its method, a plurality of light beams are directed at different irradiation positions on the surface of the exposure area on the substrate to be exposed at an angle of 70° with respect to the optical axis direction of the reduction projection lens. The light images reflected from each of the different irradiation positions on the surface of the exposure area are focused on an image plane at least in the position detection direction, and each irradiation position on the surface of the exposure area that is imaged on the image plane is The position of each light image corresponding to the height is detected by at least a one-dimensional image sensor, and the surface of the exposure area on the exposed substrate is detected based on the signal corresponding to the height of each irradiation position output from the image sensor. The inclination of the reduction projection lens with respect to the imaging plane is calculated, and the inclination of the exposed substrate is adjusted based on the calculated inclination of the exposed area on the surface of the exposed substrate. The surface can be aligned with the imaging plane of the reduction projection lens with high precision, and the fine circuit pattern formed on the mask (reticle) can be reduced to the exposure area on the exposed substrate with high resolution using the reduction projection lens. By making projection exposure printing possible, it is possible to further improve the yield of LSI products and achieve higher integration.
第１図は本発明に係る縮小投影露光装置におい
て、焦点合わせする光学・機械系を示す補足説明
図、第２図は第１図における各部スリツト像の形
状を示す構成図、第３図は検出領域が微小な場合
の焦点検出位置のずれを示す概念図、第４図は本
発明に従つて複数のスリツト像を用いた平均的焦
点位置の検出を示す概念図、第５図は本発明にか
かる多重スリツト方式を示す要部の構成図、第６
図はリニアイメージセンサの受光面上に投影結像
されたスリツト像を添画したセンサ画素位置に対
する出力の分布を示す線図、第７図は第６図の１
スリツト分を幅方向に拡大して同様に受光面上の
スリツト像を添画したセンサ画素位置に対する出
力の分布を拡大して示す線図、第８図はスリツト
をXYの二方向に設けた焦点合せ装置の全体構成
図、第９図ａ〜ｄは第８図の方式による被観察物
の姿勢状態を示す概念図、第１０図はウエハに塗
布したフオトレジストに照射した光束の進行方向
とセンサの出力を示す概念図、第１１図は入射角
と偏光の違いによるレジスト上での反射率の変化
を示す線図である。
１……縮小レンズ、２……ウエハ、３……レー
ザ光源、５……スリツト、６……第１レンズ、９
……第２レンズ、１０……対物レンズ、１２……
リニアイメージセンサ、１３……第２円筒レン
ズ、１４……フオトレジスト、１５……多重スリ
ツト、１６……ウエハステージ、１７……多重ス
リツト、１８……エリアイメージセンサ。
Fig. 1 is a supplementary explanatory diagram showing the optical and mechanical system for focusing in the reduction projection exposure apparatus according to the present invention, Fig. 2 is a configuration diagram showing the shape of the slit image of each part in Fig. 1, and Fig. 3 is a detection diagram. FIG. 4 is a conceptual diagram showing the deviation of the focus detection position when the area is minute. FIG. 4 is a conceptual diagram showing the detection of the average focal point position using a plurality of slit images according to the present invention. FIG. A configuration diagram of the main parts showing such a multiple slit system, No. 6
The figure is a line diagram showing the output distribution with respect to the sensor pixel position with the slit image projected and formed on the light-receiving surface of the linear image sensor.
A line diagram showing an enlarged distribution of output with respect to the sensor pixel position with the slit portion enlarged in the width direction and the slit image on the light-receiving surface similarly attached. Figure 8 shows the focal point with the slit provided in the two directions of X and Y. The overall configuration of the alignment device, Figures 9a to 9d are conceptual diagrams showing the posture of the object to be observed using the method shown in Figure 8, and Figure 10 shows the traveling direction of the light beam irradiated onto the photoresist coated on the wafer and the sensor. FIG. 11 is a diagram showing the change in reflectance on the resist due to the difference in incident angle and polarization. DESCRIPTION OF SYMBOLS 1... Reduction lens, 2... Wafer, 3... Laser light source, 5... Slit, 6... First lens, 9
...Second lens, 10...Objective lens, 12...
Linear image sensor, 13... second cylindrical lens, 14... photoresist, 15... multiple slits, 16... wafer stage, 17... multiple slits, 18... area image sensor.
Claims (1)
レンズにより被露光基板上の露光領域に縮小投影
露光する縮小投影露光装置において、前記被露光
基板を前記縮小投影レンズの光軸方向に微移動さ
せ、更に前記縮小投影レンズの結像面に対する前
記被露光基板を微回動させるステージ手段と、前
記縮小投影レンズと前記被露光基板との間の側方
より複数の光束を前記被露光基板上の露光領域表
面の異なる照射位置に縮小投影レンズの光軸方向
に対して70°以上の傾斜角度で照射する照射手段
と、該照射手段で照射されて露光領域表面の異な
る照射位置の各々から反射する光像を、前記縮小
投影レンズと前記被露光基板との間の側方より検
出して少なくとも位置検出方向について像面に結
像させる検出結像光学系と、該検出結像光学系に
より像面に結像された露光領域表面の各照射位置
の高さに対応した各光像の位置を検出して該各照
射位置の高さに対応した信号を出力する少なくと
も一次元のイメージセンサと、該イメージセンサ
から出力される各照射位置の高さに対応した信号
に基づいて露光領域表面の前記結像面に対する傾
きを算出し、該算出された露光領域表面の傾きに
基づいて前記ステージ手段を微回動駆動制御する
制御手段とを備えたことを特徴とする縮小投影露
光装置。 ２ 前記制御手段は、前記イメージセンサから出
力される各照射位置の高さに対応した信号に基づ
いて露光領域表面の前記結像面に対する平均的な
変位を算出し、該算出された変位に基づいて前記
ステージ手段を縮小投影レンズの光軸方向に微移
動駆動制御する制御手段を有することを特徴とす
る特許請求の範囲第１項記載の縮小投影露光装
置。 ３ 前記照射手段は、前記複数の光束を、前記露
光領域表面の異なる照射位置に対してＳ偏光で照
射するように構成したことを特徴とする特許請求
の範囲第１項記載の縮小投影露光装置。 ４ 前記照射手段には、前記複数の光束を、前記
位置検出方向に対してほぼ直角方向に延べたスリ
ツト状光束で形成する光学手段を有することを特
徴とする特許請求の範囲第１項記載の縮小投影露
光装置。 ５ 更に前記検出結像光学系には、照射位置の
各々から反射するスリツト状光像を、前記位置検
出方向に対してほぼ直角方向に集光させて像面に
結像させる集光光学系を有することを特徴とする
特許請求の範囲第４項記載の縮小投影露光装置。 ６ マスクに形成された回路パターンを縮小投影
レンズにより被露光基板上の露光領域表面に縮小
投影露光する縮小投影露光方法において、照射手
段により前記縮小投影レンズと前記被露光基板と
の間の側方より複数の光束を前記被露光基板上の
露光領域表面の異なる照射位置に縮小投影レンズ
の光軸方向に対して70°以上の傾斜角度で照射し、
該照射されて露光領域表面の異なる照射位置の
各々から反射する光像を、前記縮小投影レンズと
前記被露光基板との間の側方より検出して結像光
学系により少なくとも位置検出方向について像面
に結像させ、該像面に結像された露光領域表面の
各照射位置の高さに対応した各光像の位置を少な
くとも一次元のイメージセンサにより検出して該
各照射位置の高さに対応した信号を出力し、該出
力される各照射位置の高さに対応した信号に基づ
いて露光領域表面の前記結像面に対する傾きを算
出し、該算出された露光領域表面の傾きに基づい
て被露光基板を載置したステージ手段を微回動駆
動制御して露光領域表面の前記結像面に対する傾
きを補正することを特徴とする縮小投影露光方
法。 ７ 前記複数の光束を、前記露光領域表面の異な
る照射位置に対してＳ偏光で照射することを特徴
とする特許請求の範囲第６項記載の縮小投影露光
方法。 ８ マスクに形成された回路パターンを縮小投影
レンズにより被露光基板上の露光領域表面に縮小
投影露光する縮小投影露光装置において、照射手
段により前記縮小投影レンズと前記被露光基板と
の間の側方より複数の光束を前記被露光基板上の
露光領域表面の異なる照射位置に縮小投影レンズ
の光軸方向に対して70°以上の傾斜角度で照射し、
該照射されて露光領域表面の異なる照射位置の
各々から反射する光像を、前記縮小投影レンズと
前記被露光基板との間の側方より検出して結像光
学系により少なくとも位置検出方向について像面
に結像させ、該像面に結像された露光領域表面の
各照射位置の高さに対応した各光像の位置を少な
くとも一次元のイメージセンサにより検出して該
各照射位置の高さに対応した信号を出力し、該出
力される各照射位置の高さに対応した信号に基づ
いて露光領域表面の前記結像面に対する傾きを算
出し、該算出された露光領域表面の傾きに基づい
て被露光基板を載置したステージ手段を微回動駆
動制御して露光領域表面の前記結像面に対する傾
きを補正し、更に前記イメージセンサから出力さ
れる各照射位置の高さに対応した信号に基づいて
露光領域表面の前記結像面に対する平均的な変位
を算出し、該算出された変位に基づいて前記ステ
ージ手段を縮小投影レンズの光軸方向に微移動駆
動制御して露光領域表面を前記結像面に合わせる
ことを特徴とする縮小投影露光方法。 ９ 前記複数の光束を、前記露光領域の異なる照
射位置に対してＳ偏光で照射することを特徴とす
る特許請求の範囲第８項記載の縮小投影露光方
法。[Scope of Claims] 1. In a reduction projection exposure apparatus that performs reduction projection exposure of a circuit pattern formed on a mask onto an exposure area on a substrate to be exposed using a reduction projection lens, the substrate to be exposed is positioned in the optical axis direction of the reduction projection lens. stage means for slightly moving the substrate to be exposed relative to the image forming surface of the reduction projection lens; An irradiation means that irradiates different irradiation positions on the surface of the exposure area on the exposure substrate at an angle of inclination of 70° or more with respect to the optical axis direction of the reduction projection lens; a detection and imaging optical system that detects a light image reflected from each from a side between the reduction projection lens and the substrate to be exposed and forms the image on an image plane at least in the position detection direction; At least one-dimensional image that detects the position of each light image corresponding to the height of each irradiation position on the surface of the exposure area formed on the image plane by the system and outputs a signal corresponding to the height of each irradiation position. Based on the sensor and a signal corresponding to the height of each irradiation position output from the image sensor, calculate the inclination of the exposure area surface with respect to the image forming plane, and based on the calculated inclination of the exposure area surface, 1. A reduction projection exposure apparatus comprising: a control means for controlling a stage means in a fine rotational manner. 2. The control means calculates an average displacement of the exposure area surface with respect to the imaging plane based on a signal corresponding to the height of each irradiation position output from the image sensor, and calculates an average displacement of the exposure area surface with respect to the imaging plane based on the calculated displacement. 2. The reduction projection exposure apparatus according to claim 1, further comprising control means for finely moving and controlling the stage means in the optical axis direction of the reduction projection lens. 3. The reduction projection exposure apparatus according to claim 1, wherein the irradiation means is configured to irradiate the plurality of light beams as S-polarized light onto different irradiation positions on the surface of the exposure area. . 4. The method according to claim 1, wherein the irradiation means includes an optical means for forming the plurality of light beams into a slit-like light beam extending in a direction substantially perpendicular to the position detection direction. Reduction projection exposure equipment. 5. The detection and imaging optical system further includes a condensing optical system that condenses the slit-shaped light images reflected from each of the irradiation positions in a direction substantially perpendicular to the position detection direction to form an image on an image plane. A reduction projection exposure apparatus according to claim 4, characterized in that the reduction projection exposure apparatus comprises: 6 In a reduction projection exposure method in which a circuit pattern formed on a mask is subjected to reduction projection exposure on the surface of an exposure area on a substrate to be exposed using a reduction projection lens, an irradiation means is used to expose a side surface between the reduction projection lens and the substrate to be exposed. irradiating a plurality of light beams to different irradiation positions on the surface of the exposure area on the substrate to be exposed at an inclination angle of 70° or more with respect to the optical axis direction of the reduction projection lens,
The irradiated light images reflected from different irradiation positions on the surface of the exposure area are detected from the side between the reduction projection lens and the substrate to be exposed, and an image is formed at least in the position detection direction by an imaging optical system. The image is formed on a surface, and the position of each light image corresponding to the height of each irradiation position on the surface of the exposure area formed on the image surface is detected by at least one-dimensional image sensor, and the height of each irradiation position is detected by using at least one-dimensional image sensor. output a signal corresponding to the height of each irradiation position, calculate the inclination of the exposure area surface with respect to the imaging plane based on the output signal corresponding to the height of each irradiation position, and based on the calculated inclination of the exposure area surface. 1. A reduction projection exposure method, comprising controlling a stage means on which a substrate to be exposed is placed to rotate slightly to correct the inclination of the surface of the exposure area with respect to the image forming plane. 7. The reduction projection exposure method according to claim 6, wherein the plurality of light beams are irradiated with S-polarized light onto different irradiation positions on the surface of the exposure area. 8 In a reduction projection exposure apparatus that performs reduction projection exposure of a circuit pattern formed on a mask onto the surface of an exposure area on a substrate to be exposed using a reduction projection lens, an irradiation means is used to expose a side surface between the reduction projection lens and the substrate to be exposed. irradiating a plurality of light beams to different irradiation positions on the surface of the exposure area on the substrate to be exposed at an inclination angle of 70° or more with respect to the optical axis direction of the reduction projection lens,
The irradiated light images reflected from different irradiation positions on the surface of the exposure area are detected from the side between the reduction projection lens and the substrate to be exposed, and an image is formed at least in the position detection direction by an imaging optical system. The image is formed on a surface, and the position of each light image corresponding to the height of each irradiation position on the surface of the exposure area formed on the image surface is detected by at least one-dimensional image sensor, and the height of each irradiation position is detected by using at least one-dimensional image sensor. output a signal corresponding to the height of each irradiation position, calculate the inclination of the exposure area surface with respect to the imaging plane based on the output signal corresponding to the height of each irradiation position, and based on the calculated inclination of the exposure area surface. The stage means on which the substrate to be exposed is mounted is controlled to rotate slightly to correct the inclination of the surface of the exposure area with respect to the image forming plane, and furthermore, a signal corresponding to the height of each irradiation position is output from the image sensor. An average displacement of the surface of the exposure area with respect to the image forming plane is calculated based on the calculated displacement, and the stage means is controlled to be finely moved in the optical axis direction of the reduction projection lens based on the calculated displacement to change the surface of the exposure area. A reduction projection exposure method characterized by aligning the image plane with the image forming plane. 9. The reduction projection exposure method according to claim 8, wherein the plurality of light beams are irradiated with S-polarized light to different irradiation positions in the exposure area.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP59195728A JPS6174338A (en) | 1984-09-20 | 1984-09-20 | Optical alignment device |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP59195728A JPS6174338A (en) | 1984-09-20 | 1984-09-20 | Optical alignment device |
Related Child Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP6211247A Division JP2728368B2 (en) | 1994-09-05 | 1994-09-05 | Exposure method |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS6174338A JPS6174338A (en) | 1986-04-16 |
| JPH0564450B2 true JPH0564450B2 (en) | 1993-09-14 |
Family
ID=16345973
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP59195728A Granted JPS6174338A (en) | 1984-09-20 | 1984-09-20 | Optical alignment device |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS6174338A (en) |
Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS6336526A (en) * | 1986-07-30 | 1988-02-17 | Oki Electric Ind Co Ltd | Wafer exposure equipment |
| JP2556015B2 (en) * | 1986-12-25 | 1996-11-20 | 株式会社ニコン | Position shift detector |
| US6094268A (en) * | 1989-04-21 | 2000-07-25 | Hitachi, Ltd. | Projection exposure apparatus and projection exposure method |
Citations (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS516565A (en) * | 1974-06-06 | 1976-01-20 | Ibm | KOGAKUTEKIFUKUSHAKINIOITE BUTSUTAIHYOMENOYOBI * MOSHIKUHAZOHYOMENOJIDOTEKINIICHITSUKERUTAMENO HOHO |
| JPS55134812A (en) * | 1979-04-02 | 1980-10-21 | Optimetrix Corp | Optical collection system |
| JPS5632114A (en) * | 1979-06-12 | 1981-04-01 | Philips Nv | Optical image forming system |
| JPS5696203A (en) * | 1979-12-27 | 1981-08-04 | Fujitsu Ltd | Detection device for optical position |
| JPS56101112A (en) * | 1980-01-16 | 1981-08-13 | Fujitsu Ltd | Exposure method |
| JPS58156937A (en) * | 1982-03-12 | 1983-09-19 | Hitachi Ltd | Exposing device |
| JPS5947731A (en) * | 1982-09-10 | 1984-03-17 | Hitachi Ltd | Automatic focusing mechanism of projection exposing apparatus |
| JPS5999216A (en) * | 1982-11-27 | 1984-06-07 | Jeol Ltd | Measuring device of surface height of body |
| JPS5999215A (en) * | 1982-11-27 | 1984-06-07 | Jeol Ltd | Measuring device of surface height of body |
| JPS59121932A (en) * | 1982-12-28 | 1984-07-14 | Fujitsu Ltd | Automatic focusing control unit |
-
1984
- 1984-09-20 JP JP59195728A patent/JPS6174338A/en active Granted
Patent Citations (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS516565A (en) * | 1974-06-06 | 1976-01-20 | Ibm | KOGAKUTEKIFUKUSHAKINIOITE BUTSUTAIHYOMENOYOBI * MOSHIKUHAZOHYOMENOJIDOTEKINIICHITSUKERUTAMENO HOHO |
| JPS55134812A (en) * | 1979-04-02 | 1980-10-21 | Optimetrix Corp | Optical collection system |
| JPS5632114A (en) * | 1979-06-12 | 1981-04-01 | Philips Nv | Optical image forming system |
| JPS5696203A (en) * | 1979-12-27 | 1981-08-04 | Fujitsu Ltd | Detection device for optical position |
| JPS56101112A (en) * | 1980-01-16 | 1981-08-13 | Fujitsu Ltd | Exposure method |
| JPS58156937A (en) * | 1982-03-12 | 1983-09-19 | Hitachi Ltd | Exposing device |
| JPS5947731A (en) * | 1982-09-10 | 1984-03-17 | Hitachi Ltd | Automatic focusing mechanism of projection exposing apparatus |
| JPS5999216A (en) * | 1982-11-27 | 1984-06-07 | Jeol Ltd | Measuring device of surface height of body |
| JPS5999215A (en) * | 1982-11-27 | 1984-06-07 | Jeol Ltd | Measuring device of surface height of body |
| JPS59121932A (en) * | 1982-12-28 | 1984-07-14 | Fujitsu Ltd | Automatic focusing control unit |
Also Published As
| Publication number | Publication date |
|---|---|
| JPS6174338A (en) | 1986-04-16 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| EXPY | Cancellation because of completion of term |