JPS62140419A - Position detector of surface - Google Patents
Position detector of surfaceInfo
- Publication number
- JPS62140419A JPS62140419A JP60281125A JP28112585A JPS62140419A JP S62140419 A JPS62140419 A JP S62140419A JP 60281125 A JP60281125 A JP 60281125A JP 28112585 A JP28112585 A JP 28112585A JP S62140419 A JPS62140419 A JP S62140419A
- Authority
- JP
- Japan
- Prior art keywords
- light
- wafer
- detecting
- detection
- measured
- 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
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
- 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
- G03F9/7003—Alignment type or strategy, e.g. leveling, global alignment
- G03F9/7023—Aligning or positioning in direction perpendicular to substrate surface
- G03F9/7026—Focusing
Landscapes
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Exposure Of Semiconductors, Excluding Electron Or Ion Beam Exposure (AREA)
- Optical Radar Systems And Details Thereof (AREA)
- Preparing Plates And Mask In Photomechanical Process (AREA)
- Exposure And Positioning Against Photoresist Photosensitive Materials (AREA)
Abstract
Description
【発明の詳細な説明】
［産業上の利用分野］
本発明は、物体表面の基準面からの隔りを検知する面位
置検知装置に関する。このような面位置検知装置は、例
えば半導体製造の分野において、半導体ウェハ表面にレ
チクルパターンを繰返し縮小投影露光するステッパと呼
ばれる露光装置の自動態点制御装置用として上記ウェハ
表面とレチクルパターン結像面とのずれを検知するため
に好適に用いられる。DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a surface position detection device that detects the distance of an object surface from a reference surface. Such a surface position detection device is used, for example, in the field of semiconductor manufacturing, for an automatic position control device of an exposure device called a stepper, which repeatedly performs reduction projection exposure of a reticle pattern onto the surface of a semiconductor wafer. It is suitably used to detect the deviation between the two.
［従来の技術］
従来の縮少投影露光装置のウェハ面位置検出方法として
は、エアマイクロセンサを用いる方法と、ウェハ面に斜
め方向から光束を入射させ、その反射光の位置ずれ量を
検出する方法（光学方式）とが知られている。[Prior Art] Conventional methods for detecting the position of a wafer surface in a reduction projection exposure apparatus include a method using an air microsensor, and a method in which a beam of light is incident on the wafer surface from an oblique direction and the amount of positional deviation of the reflected light is detected. method (optical method) is known.
しかしながら、エアマイクロにセンサよる方法では、
■パターン焼き付は部が直接に副長できない、■応答性
が光学式に比べて遅い、
■エアマイクロセンサのノズルとウェハ面の間隔を５０
〜６０μｍ程度に近接させなければ、高精度の検出がで
きない、
などという問題があった。However, in the method using an air microsensor, ■pattern printing cannot be done directly by the sub-layer, ■responsiveness is slower than the optical method, and ■the distance between the nozzle of the air microsensor and the wafer surface is set at 50°.
There was a problem in that highly accurate detection could not be achieved unless the distance was approximately 60 μm.
一方、光学方式の場合は、パターン焼き付は部が直接に
測長でき、応答性も早いが、ウェハ上に塗布されたレジ
ストの存在によってレジスト表面で反射した光とウェハ
表面で反射した光とが干渉を起し、検出誤差を生じるた
め高精度の位置検出が困難であるという問題があった。On the other hand, in the case of the optical method, the length of the pattern can be measured directly and the response is fast, but due to the presence of the resist coated on the wafer, the light reflected on the resist surface and the light reflected on the wafer surface are different. There is a problem in that highly accurate position detection is difficult because interference occurs and detection errors occur.
［発明の目的］
本発明の目的は、上述の従来形における問題点に鑑み、
光学方式の面位置検出装置において、波長の異なる複数
の光束を入射することにより、被検出面およびその近傍
（フォトレジストを塗布した半導体ウェハであればレジ
スト表面およびウェハ表面）で反射した検出光の干渉作
用を平均化させ、検出光の干渉作用による検出誤差を軽
減するという構想に基づき、面位置検知精度を向上させ
ることにある。[Object of the invention] The object of the present invention is to solve the problems of the conventional type described above,
In an optical surface position detection device, by inputting multiple light beams with different wavelengths, detection light reflected from the detection surface and its vicinity (for a semiconductor wafer coated with photoresist, the resist surface and wafer surface) is detected. The purpose of this invention is to improve surface position detection accuracy based on the concept of averaging the interference effect and reducing detection errors due to the interference effect of detection light.
［実施例の説明］ 以下、図面を用いて本発明の詳細な説明する。[Explanation of Examples] Hereinafter, the present invention will be explained in detail using the drawings.
第１図は、本発明の一実施例に係る縮小投影露光装置用
自動焦点制御装置の構成を示す。同図において、１は縮
小投影レンズであり、その下方にウェハ２が位置してい
る。ウェハ２は上下方向に移動可能なステージ３に乗っ
ている。自動焦点制御装置の光学系は複数の光源４，５
を有している（第１図においては、簡単の為、複数光源
として２つの光源のみ描いである）。光源としては、波
長の異なるレーザあるいはＬＥＤ等を用いる。この光源
４および５より出た光束（検出光）は、ビームスプリッ
タ（またはハーフミラ−でもよい）６により同一の光路
を形成し、レンズ７を経た後、ミラー８で反射されウェ
ハ２上の反射点に結像する。FIG. 1 shows the configuration of an automatic focus control device for a reduction projection exposure apparatus according to an embodiment of the present invention. In the figure, 1 is a reduction projection lens, and a wafer 2 is located below it. The wafer 2 is placed on a stage 3 that is vertically movable. The optical system of the automatic focus control device includes a plurality of light sources 4 and 5.
(In FIG. 1, for simplicity, only two light sources are depicted as a plurality of light sources). As the light source, lasers or LEDs with different wavelengths are used. The light beams (detection light) emitted from the light sources 4 and 5 form the same optical path through a beam splitter (or a half mirror) 6, pass through a lens 7, and are reflected by a mirror 8 to a reflection point on the wafer 2. image is formed.
この時、検出光のウェハ面への入射角を８０’以上、す
なわちウェハ面と入射光束とのなす角θを１０°以下と
し、また、検出光をウェハに対してＳ偏光となる様にす
ると、レジスト表面からの反射光強度が支配的となりウ
ェハ基板よりの反射光の影響を小さくする事ができる。At this time, the angle of incidence of the detection light on the wafer surface is set to be 80' or more, that is, the angle θ between the wafer surface and the incident light beam is set to 10° or less, and the detection light is made to be S-polarized with respect to the wafer. , the intensity of the reflected light from the resist surface becomes dominant, and the influence of the reflected light from the wafer substrate can be reduced.
ウェハ２で反射した光束はミラー９で反射され、レンズ
１０を通り、偏光板１１（または偏光ビームスプリッタ
）を通った後、ポジションセンサダイオード１２（また
は分割センサ等）に入光、結像する。The light beam reflected by the wafer 2 is reflected by a mirror 9, passes through a lens 10, and a polarizing plate 11 (or a polarizing beam splitter), and then enters a position sensor diode 12 (or a split sensor, etc.) to form an image.
偏光板１１（または偏光ビームスプリッタ）は、ウェハ
で反射した光束中のＳ偏光成分のみをポジションセンサ
ダイオード１２に到達させることにより、検出光中のウ
ェハ基板での反射成分をさらに少なくするためのもので
ある。The polarizing plate 11 (or polarizing beam splitter) allows only the S-polarized component in the light beam reflected by the wafer to reach the position sensor diode 12, thereby further reducing the component reflected by the wafer substrate in the detection light. It is.
この自動焦点制御装置においては、ウェハ面上の光束の
反射点と受光素子上の入射点を結像関係に保つことによ
り、ウェハの上下方向の位置ずれを受光素子上の光束の
入光位置として検知し、投影レンズの焦点位置の自動制
御を行なうようにしている。In this automatic focus control device, by maintaining an imaging relationship between the reflection point of the light beam on the wafer surface and the incident point on the light receiving element, vertical positional deviation of the wafer can be used as the incident position of the light beam on the light receiving element. This is detected and the focal position of the projection lens is automatically controlled.
光学方式の焦点位置検知装置における位置ずれ検出誤差
の原因として、ウェハの傾き、およびウェハ上に塗布さ
れた光透過物体であるレジストの存在が考えられるが、
前者のウェハの傾きにより生じる検出誤差は、上述のよ
うに、ウェハ上の反射点と受光素子上の光束の入射点と
を結像関係に保つことにより原理的に除くことができる
。Possible causes of positional deviation detection errors in optical focus position detection devices include the tilt of the wafer and the presence of a resist, which is a light-transmitting object, coated on the wafer.
The former detection error caused by the tilt of the wafer can be eliminated in principle by maintaining the imaging relationship between the reflection point on the wafer and the incident point of the light beam on the light receiving element, as described above.
一方、後者のレジストの存在は、レジスト表面での反射
光とウェハ表面での反射光との間に干渉が生じることに
より、受光素子上に結像した光束の強度の重心のずれと
なって現われる。すなわち、レジストの厚み、あるいは
検出光として用いる光の波長によって検出される位置が
異なることを意味する。On the other hand, the presence of the latter resist causes interference between the light reflected from the resist surface and the light reflected from the wafer surface, which appears as a shift in the center of gravity of the intensity of the light beam focused on the photodetector. . This means that the detected position differs depending on the thickness of the resist or the wavelength of the light used as the detection light.
従って、より高精度の位置検出を可能とするためには、
この検出光に対するレジストの干渉効果を除くことがぜ
ひとも必要となる。Therefore, in order to enable more accurate position detection,
It is absolutely necessary to eliminate the interference effect of the resist on this detection light.
次に、第２図および第３図を用いて検出光に対するレジ
ストの干渉効果による検出誤差の軽減について説明する
。Next, the reduction of detection errors due to the interference effect of the resist with respect to the detection light will be explained using FIGS. 2 and 3.
第２図は、レジスト１４の塗布されたウェハ２上に、一
定のビーム径をもち、ビーム径内で一様の強度をもつ光
束１３が結像した状態で入射し、レジスト１４の表面お
よびウェハ２の表面で反射することにより、ビーム径内
で異なった強度の分布を示す光束１５を形成する状態を
示した模式図である。FIG. 2 shows that a light beam 13 having a constant beam diameter and a uniform intensity within the beam diameter is incident on a wafer 2 coated with a resist 14 in an imaged state, and the surface of the resist 14 and the wafer 2 are 2 is a schematic diagram showing a state in which a light beam 15 exhibiting different intensity distributions within the beam diameter is formed by reflection on the surface of the light beam 2. FIG.
また、第３図は、このレジスト１４およびウェハ２の表
面で反射し形成された光束１５が光学系により受光素子
上に結像された状態での強度の分布を示すグラフである
。Further, FIG. 3 is a graph showing the intensity distribution in a state where the light beam 15 reflected and formed by the surfaces of the resist 14 and the wafer 2 is imaged on the light receiving element by the optical system.
第２図において、一定のビーム径をもちビーム径内で一
様の強度の分布を示す光束１３がレジスト１４の塗布さ
れたウェハ２上に斜め方向から入射する。この時、光束
１３は、レジスト１４の表面で反射する成分と、レジス
ト１４を透過してウェハ２の表面とレジスト１４の表面
との間で多重反射を繰り返した後、再びレジスト１４外
に出て行く成分とに分けられる。この様にレジスト１４
表面で反射された成分とウェハ２表面で反射された成分
とは合成され、第３図に示すようにビーム径内で異なっ
た強度分布を示す光束１５が形成されることになる。こ
の光束１５は、第１図のミラー９、レンズ１０および偏
光板１１を通って受光素子１２上に結像される。In FIG. 2, a light beam 13 having a constant beam diameter and exhibiting a uniform intensity distribution within the beam diameter is incident on a wafer 2 coated with a resist 14 from an oblique direction. At this time, the light beam 13 undergoes multiple reflections between the component reflected by the surface of the resist 14 and the component transmitted through the resist 14 between the surface of the wafer 2 and the surface of the resist 14, and then exits outside the resist 14 again. It is divided into components that go. Resist 14 like this
The components reflected on the surface of the wafer 2 and the components reflected on the surface of the wafer 2 are combined to form a light beam 15 having different intensity distributions within the beam diameter, as shown in FIG. This light beam 15 passes through the mirror 9, lens 10 and polarizing plate 11 shown in FIG. 1, and forms an image on the light receiving element 12.
第３図において、グラフ■はある波長λコを検出光とし
て用いた場合の受光素子上の光強度分布を示す。また、
グラフ■および■は各々異なった波長λ２．λ３を検出
光として用いた場合の受光素子上での光強度分布を示す
。さらに、グラフ■は複数の波長λ１〜λｎを検出光と
して用いた場合の受光素子上での光強度分布を示す。In FIG. 3, graph (2) shows the light intensity distribution on the light receiving element when a certain wavelength λ is used as detection light. Also,
Graphs ■ and ■ are for different wavelengths λ2. The light intensity distribution on the light receiving element is shown when λ3 is used as detection light. Furthermore, graph (2) shows the light intensity distribution on the light receiving element when a plurality of wavelengths λ1 to λn are used as detection light.
検出光として、単色（または準単色）の光源を用いた場
合の受光素子上での検出光の強度分布は、グラフ■、■
、■に示される様に、レジスト１４の表面で反射した成
分とウェハ２表面で反射した成分の干渉のために複雑な
強度分布を示す。また、この強度の分布状態は検出光の
波長およびレジスト１４の厚みによって異なる。また、
受光素子によって検出光の強度分布の重心１６．１７．
１８が位置信号として出力されるわけであるが、検出光
の波長またはレジスト１４の厚みが変わると干渉状態が
変化し、重心１６．１７．１８の位置も変化し、検出誤
差となって現われる。The intensity distribution of the detected light on the light receiving element when a monochromatic (or quasi-monochromatic) light source is used as the detection light is shown in the graphs ■ and ■.
, ■, a complicated intensity distribution is exhibited due to interference between the component reflected from the surface of the resist 14 and the component reflected from the surface of the wafer 2. Further, the distribution state of this intensity differs depending on the wavelength of the detection light and the thickness of the resist 14. Also,
Center of gravity of the intensity distribution of light detected by the light receiving element 16.17.
18 is output as a position signal, but if the wavelength of the detection light or the thickness of the resist 14 changes, the interference state changes, and the positions of the centers of gravity 16, 17, and 18 also change, resulting in detection errors.
ところで、これは本発明者等が種々検討の末、知見した
ことであるが、複数の単色（または準単色）の光源を検
出光として用いた場合の受光素子上での検出光の強度分
布は、グラフ■に示される様に、多波長の光源を用いる
ことによりレジストの存在に伴う干渉効果が平均化され
、検出光の強度分布の重心１９もレジストの膜厚にかか
わらず安定した値を示す。それ故、このような多波長の
光源を用いて光学方式のウェハ表面位置を検出すればレ
ジストの存在に伴う位置の検出誤差を除くことが可能と
なる。By the way, this is what the inventors found after various studies, but when multiple monochromatic (or quasi-monochromatic) light sources are used as detection light, the intensity distribution of the detection light on the light receiving element is As shown in the graph ■, by using a multi-wavelength light source, the interference effect due to the presence of the resist is averaged out, and the center of gravity 19 of the intensity distribution of the detected light also shows a stable value regardless of the resist film thickness. . Therefore, by optically detecting the wafer surface position using such a multi-wavelength light source, it is possible to eliminate position detection errors caused by the presence of resist.
また、第１図に示した様に波長の異なる複数の光源を用
いるとともに、ウェハへの入射光がウェハとなす角θを
１０°以下にすること、および検出光としてウェハに対
するＳ偏光を用いることにより、ウェハ表面での反射光
が減少し、本発明の効果を、さらに大ならしめることが
できる。In addition, as shown in Figure 1, multiple light sources with different wavelengths are used, the angle θ that the incident light makes with the wafer is 10 degrees or less, and S-polarized light with respect to the wafer is used as the detection light. As a result, reflected light on the wafer surface is reduced, and the effects of the present invention can be further enhanced.
なお、上記干渉効果の平均化は、上記複数波長の光を混
合してウェハ上に同時に照射し、その反射光を検出する
ことによっても達成されるが、これらの多光を、例えば
時分割で照射する等により、個々独立に検出し、得られ
た複数個の検出信号を演算処理することにより行なって
もよい。特に、後者の方式によると、調整誤差等による
多光ごとの照射光路のずれまでも含めて処理することが
できる。これは、予めレジストを塗布しない基準ウェハ
を用いて各光源を１つずつ発光させながら、各光源に対
応する受光位置を測定し、実際のウエハ表面位置は各光
源の発光に同期してこれらの受光位置を基準または参照
位置として測定するようにすればよい。このような処理
は、マイクロプロセッサ等の中央処理装置（ＣＰＵ）を
用いることにより、当業者ならば容易に実施することが
できる。Note that the above-mentioned averaging of the interference effect can also be achieved by mixing the above-mentioned multiple wavelengths of light, irradiating the wafer at the same time, and detecting the reflected light. The detection may be performed by individually detecting the signals by irradiating them, etc., and then calculating and processing the obtained plurality of detection signals. In particular, according to the latter method, it is possible to process even the deviation of the irradiation optical path for each multi-beam beam due to adjustment errors and the like. This method uses a reference wafer that is not coated with resist in advance, causes each light source to emit light one by one, and measures the light receiving position corresponding to each light source. The measurement may be performed using the light receiving position as a standard or reference position. Such processing can be easily carried out by those skilled in the art by using a central processing unit (CPU) such as a microprocessor.
前記の実施例において、光源としてはＬＥＤまたはレー
ザ等を用いることができる。また、受光素子としては、
ポジションセンサディテクタ（ＰＳＤ）、分割センサデ
ィテクタおよびＣＣＤなどの位置検出能力をもつ光電変
換素子を用いることができる。In the embodiments described above, the light source may be an LED, a laser, or the like. In addition, as a light receiving element,
A photoelectric conversion element having position detection capability such as a position sensor detector (PSD), a split sensor detector, and a CCD can be used.
特に、受光素子にポジションセンサディテクタを用いる
場合は、ポジションセンサディテクタにおける基準点の
時間変化に伴う位置信号の検出誤差をなくすために、第
４図に示すように、基準信号検出系を用いることが考え
られる。In particular, when using a position sensor detector as a light receiving element, it is recommended to use a reference signal detection system as shown in Fig. 4 in order to eliminate position signal detection errors caused by time changes in the reference point in the position sensor detector. Conceivable.
同図において、基準光源２０より発せられた光束は、レ
ンズ２１を経てビームスプリッタ（またはハーフミラ−
）２２により方向を変えられた後、ポジションセンサデ
ィテクタ１２上に結像する。In the same figure, the light beam emitted from the reference light source 20 passes through the lens 21 and the beam splitter (or half mirror).
) 22, the image is formed on the position sensor detector 12.
ここで、本装置は、組み立て調整する際に基準光源２０
および複数の光源４．５より得られるポジションセンサ
ディテクタの位置信号がゼロとなるように、光学系の光
軸およびポジションセンサディテクタ１２の基準点が調
整されているものとする。Here, when assembling and adjusting this device, the reference light source 20
It is assumed that the optical axis of the optical system and the reference point of the position sensor detector 12 are adjusted so that the position signal of the position sensor detector obtained from the plurality of light sources 4.5 becomes zero.
次に、第４図の装置において、実際にウェハ２を投影レ
ンズ１の焦点面に位置合せする場合を考える。この時ポ
ジションセンサディテクタ１２が、初めの調整時点より
、基準点が経時変化Δを生じているとしても、ウェハ２
に対する検出光を検出する前に、先ず、基準光源２０を
発光させ、その位置信号を検出することにより、ポジシ
ョンセンサディテクタ１２の基準点の経時変化Δを計測
することができる。Next, consider the case where the wafer 2 is actually aligned to the focal plane of the projection lens 1 in the apparatus shown in FIG. At this time, even if the reference point has changed over time Δ since the initial adjustment, the position sensor detector 12 detects that the wafer 2
Before detecting the detection light for the reference point, first, the reference light source 20 is made to emit light and its position signal is detected, thereby making it possible to measure the change over time Δ of the reference point of the position sensor detector 12.
次に、ウェハ２に対する検出光の位置信号Ｓを検出する
。この時、基準点の経時変化Δと位置信号Ｓを測定する
時間間隔は、ポジションセンサディテクタ１２の基準点
の経時変化が生じない程の小なる時間内で行なうものと
する。この位置信号Ｓはポジションセンサディテクタ１
２の基準点の経時変化Δを含むものであるので、上記基
準光源２ｏを発光させた時の位置信号Δを引いてやるこ
とにより、高精度の位置検出が可能となる。すなわち、
（Ｓ−Δ）なる位置信号を用いて、焦点位置検出装置の
制御を行なうようにすれば、ポジションセンサディテク
タ１２の基準点の経時変化を含まない、高精度の焦点合
せが可能となる。Next, a position signal S of the detection light relative to the wafer 2 is detected. At this time, the time interval at which the change Δ of the reference point over time and the position signal S are measured is so small that the reference point of the position sensor detector 12 does not change over time. This position signal S is sent to the position sensor detector 1.
Since this includes the temporal change Δ of the reference point 2, highly accurate position detection is possible by subtracting the position signal Δ when the reference light source 2o is emitted. That is,
If the focus position detection device is controlled using the position signal (S-Δ), highly accurate focusing that does not include changes in the reference point of the position sensor detector 12 over time becomes possible.
また、この時、検出側のレンズ系１０の受光素子側主点
より、レンズ系１０の焦点距離だけ受光素子側にずらし
た位置にストッパ２３を設けることにより、パターンの
あるウェハ上のレジスト表面より反射される反射光の高
次の回折光成分をカットするものとする。このことによ
り、パターンのあるウェハに対して位置検出を行う際に
も、高次の回折光成分による検出光の光重心の変化をう
けないで済む。すなわち、パターンのあるウェハに対し
ても、高精度の位置検出が可能となる。At this time, by providing a stopper 23 at a position shifted toward the light receiving element by the focal length of the lens system 10 from the principal point on the light receiving element side of the lens system 10 on the detection side, the resist surface on the patterned wafer can be It is assumed that high-order diffracted light components of the reflected light are cut. As a result, even when performing position detection on a wafer with a pattern, the optical center of gravity of the detection light does not change due to higher-order diffracted light components. In other words, highly accurate position detection is possible even for wafers with patterns.
［発明の効果］
以上説明したように本発明によれば、波長の異なる複数
個の光を用い、かつこれらの光による面位置検出信号を
波長ごとに個々独立に検出してこれらの信号を基に面位
置を求めるようにしているため、レジストを塗布したウ
ェハ面の様に検出光束に対、する反射面が複数面ある場
合の検出光の干渉による検出誤差を軽減し、正確にしか
も再現性良くウェハ等の面位置を検出することができる
。[Effects of the Invention] As explained above, according to the present invention, a plurality of lights with different wavelengths are used, surface position detection signals from these lights are detected individually for each wavelength, and these signals are used as a basis. Since the surface position is determined based on the surface position, it reduces detection errors caused by interference of the detection light when there are multiple reflective surfaces that reflect the detection light beam, such as a wafer surface coated with resist, and provides accurate and reproducible results. The surface position of a wafer, etc. can be detected well.
また、本発明の装置は、特に高精度の焦点検出の要求さ
れる縮小投影細光装置の縮小投影レンズの焦点合せに有
効である。この場合、高精度の焦点検出が出来ため、高
解像のパターンが形成可能になり、より集積度の高い回
路を作成できるという効果がある。Further, the device of the present invention is particularly effective for focusing a reduction projection lens of a reduction projection narrow light device which requires highly accurate focus detection. In this case, since highly accurate focus detection is possible, a pattern with high resolution can be formed, and a circuit with a higher degree of integration can be created.
第１図は、本発明の一実施例に係る自動焦点制御装置を
示す構成図、
第２図は、レジストを塗布したウェハ上に低角度で光束
を入射、結像させた場合のレジスト表面およびウェハ表
面での光束の反射状態を示す断面図、
第３図は、レジストを塗布したウェハ上で反射された光
束が受光素子上に入光し結像した状態での検出光の強度
の分布を示すグラフ、
第４図は、受光素子としてポジシミンセンサディテクタ
を用い、基準信号検出系を具備したところの本発明の他
の実施例に係る自動焦点制御装置を示す構成図である。
１・・・縮小投影レンズ、２・・・ウェハ、３・・・ス
テージ、４，５．２０・・・レーザ（またはＬＥＤ）、
６・・・ビームスプリッタ（またはハーフミラ−）、７
、１０．２１・・・レンズ系、８，９・；・ミラー、１
１゜２２・・・偏光板（または偏光ビームスプリッタ）
、１２・・・ポジションセンサダイオード（または分割
センサーダイオードもしくはＣ０Ｄ）、１３・・・光束
（入射光束）、１４・・・レジスト、１５・・・光束（
反射光束） 、 １６．１７．１８．１９・・・強度分
布の重心、２３・・・ストッパ。
第４図
■東 鍼慄
ｅ Ｇ
（２） ｃ。
Ｏ■FIG. 1 is a configuration diagram showing an automatic focus control device according to an embodiment of the present invention. FIG. 2 shows the resist surface and the image formed when a light beam is incident at a low angle on a wafer coated with resist. Figure 3, a cross-sectional view showing the state of reflection of a light beam on the wafer surface, shows the intensity distribution of the detected light when the light beam reflected on the wafer coated with resist enters the light receiving element and forms an image. The graph shown in FIG. 4 is a block diagram showing an automatic focus control device according to another embodiment of the present invention, which uses a positimine sensor detector as a light receiving element and is equipped with a reference signal detection system. 1... Reduction projection lens, 2... Wafer, 3... Stage, 4,5.20... Laser (or LED),
6... Beam splitter (or half mirror), 7
, 10.21... Lens system, 8, 9... Mirror, 1
1゜22...Polarizing plate (or polarizing beam splitter)
, 12... Position sensor diode (or split sensor diode or C0D), 13... Luminous flux (incident luminous flux), 14... Resist, 15... Luminous flux (
reflected light flux), 16.17.18.19... center of gravity of intensity distribution, 23... stopper. Figure 4 ■ East Acupuncture G (2) c. O■
Claims (1)
の光を被測定面に斜め方向から投光する手段と、 該被測定面からの反射光を受光してその受光位置に応じ
た電気信号を出力する受光素子と、該電気信号を上記波
長ごとに個々独立に検出し、得られた複数個の検出信号
に基づいて上記被測定面の基準面からのずれ量を検知す
る電気信号処理手段とを具備することを特徴とする面位
置検知装置。 ２、前記投光手段が、前記各発光手段の出射光に対し実
質的に同一の光路を形成する第１の光学系を含む特許請
求の範囲第１項記載の面位置検知装置。 ３、前記被測定面への入射光をＳ偏光とし、かつ該入射
光の該被測定面となす角を１０°以下とした特許請求の
範囲第１または２項記載の面位置検知装置。 ４、前記投光手段が、前記各波長の光を時分割で投光す
る特許請求の範囲第１、２または３項記載の面位置検知
装置。 ５、前記被測定面と受光素子受光面とを実質的に共役に
する第２の光学系を有する特許請求の範囲第１〜４項の
いずれか１つに記載の面位置検知装置。 ６、前記被測定面が、感剤を塗布した基板における感剤
表面または基板表面である特許請求の範囲第１〜５項の
いずれか１つに記載の面位置検知装置。[Claims] 1. A means having a plurality of light emitting means having different wavelengths and projecting light of each of these wavelengths onto a surface to be measured from an oblique direction; and a means for receiving reflected light from the surface to be measured; A light-receiving element that outputs an electrical signal according to the light-receiving position, and a light-receiving element that independently detects the electrical signal for each of the wavelengths, and determines the deviation of the surface to be measured from the reference surface based on the plurality of detection signals obtained. 1. A surface position detection device comprising an electric signal processing means for detecting an amount. 2. The surface position detection device according to claim 1, wherein the light projecting means includes a first optical system that forms substantially the same optical path for the light emitted from each of the light emitting means. 3. The surface position detection device according to claim 1 or 2, wherein the incident light on the surface to be measured is S-polarized light, and the angle between the incident light and the surface to be measured is 10 degrees or less. 4. The surface position detection device according to claim 1, 2 or 3, wherein the light projecting means projects the light of each of the wavelengths in a time-division manner. 5. The surface position detection device according to any one of claims 1 to 4, further comprising a second optical system that makes the surface to be measured and the light receiving surface of the light receiving element substantially conjugate. 6. The surface position detection device according to any one of claims 1 to 5, wherein the surface to be measured is a sensitive material surface of a substrate coated with a sensitive material or a substrate surface.
Priority Applications (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP28112585A JPH0787173B2 (en) | 1985-12-16 | 1985-12-16 | Surface position detection method |
| US07/657,950 US5162642A (en) | 1985-11-18 | 1991-02-21 | Device for detecting the position of a surface |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP28112585A JPH0787173B2 (en) | 1985-12-16 | 1985-12-16 | Surface position detection method |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS62140419A true JPS62140419A (en) | 1987-06-24 |
| JPH0787173B2 JPH0787173B2 (en) | 1995-09-20 |
Family
ID=17634710
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP28112585A Expired - Lifetime JPH0787173B2 (en) | 1985-11-18 | 1985-12-16 | Surface position detection method |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH0787173B2 (en) |
Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5760205A (en) * | 1980-09-30 | 1982-04-12 | Jeol Ltd | Exposure be electron beam |
| JPS5954908A (en) * | 1982-09-22 | 1984-03-29 | Fujitsu Ltd | Surface position detecting method |
| JPS5979527A (en) * | 1982-10-29 | 1984-05-08 | Hitachi Ltd | Pattern detector |
| JPS6080223A (en) * | 1983-10-07 | 1985-05-08 | Hitachi Ltd | Light exposing device |
-
1985
- 1985-12-16 JP JP28112585A patent/JPH0787173B2/en not_active Expired - Lifetime
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5760205A (en) * | 1980-09-30 | 1982-04-12 | Jeol Ltd | Exposure be electron beam |
| JPS5954908A (en) * | 1982-09-22 | 1984-03-29 | Fujitsu Ltd | Surface position detecting method |
| JPS5979527A (en) * | 1982-10-29 | 1984-05-08 | Hitachi Ltd | Pattern detector |
| JPS6080223A (en) * | 1983-10-07 | 1985-05-08 | Hitachi Ltd | Light exposing device |
Also Published As
| Publication number | Publication date |
|---|---|
| JPH0787173B2 (en) | 1995-09-20 |
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