JPH02188907A - Face-position detection apparatus - Google Patents
Face-position detection apparatusInfo
- Publication number
- JPH02188907A JPH02188907A JP1008398A JP839889A JPH02188907A JP H02188907 A JPH02188907 A JP H02188907A JP 1008398 A JP1008398 A JP 1008398A JP 839889 A JP839889 A JP 839889A JP H02188907 A JPH02188907 A JP H02188907A
- Authority
- JP
- Japan
- Prior art keywords
- face
- observed
- image
- pattern
- wafer
- 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
- 238000001514 detection method Methods 0.000 title claims abstract description 33
- 230000001427 coherent effect Effects 0.000 claims description 4
- 238000000034 method Methods 0.000 abstract description 7
- 238000003384 imaging method Methods 0.000 description 18
- 230000003287 optical effect Effects 0.000 description 11
- 238000010586 diagram Methods 0.000 description 9
- 239000011295 pitch Substances 0.000 description 9
- 241000257465 Echinoidea Species 0.000 description 6
- 230000009467 reduction Effects 0.000 description 6
- 238000004519 manufacturing process Methods 0.000 description 5
- 239000004065 semiconductor Substances 0.000 description 5
- 238000005286 illumination Methods 0.000 description 4
- 238000005259 measurement Methods 0.000 description 3
- 230000005540 biological transmission Effects 0.000 description 2
- 230000008859 change Effects 0.000 description 2
- 238000006073 displacement reaction Methods 0.000 description 2
- 210000001747 pupil Anatomy 0.000 description 2
- 238000002834 transmittance Methods 0.000 description 2
- 230000004075 alteration Effects 0.000 description 1
- 238000006243 chemical reaction Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 210000003608 fece Anatomy 0.000 description 1
- 230000004907 flux Effects 0.000 description 1
- 230000008569 process Effects 0.000 description 1
- 230000035945 sensitivity Effects 0.000 description 1
Classifications
-
- G—PHYSICS
- G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
- G03F—PHOTOMECHANICAL PRODUCTION OF TEXTURED OR PATTERNED SURFACES, e.g. FOR PRINTING, FOR PROCESSING OF SEMICONDUCTOR DEVICES; MATERIALS THEREFOR; ORIGINALS THEREFOR; APPARATUS SPECIALLY ADAPTED THEREFOR
- G03F7/00—Photomechanical, e.g. photolithographic, production of textured or patterned surfaces, e.g. printing surfaces; Materials therefor, e.g. comprising photoresists; Apparatus specially adapted therefor
- G03F7/70—Microphotolithographic exposure; Apparatus therefor
-
- G—PHYSICS
- G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
- G03F—PHOTOMECHANICAL PRODUCTION OF TEXTURED OR PATTERNED SURFACES, e.g. FOR PRINTING, FOR PROCESSING OF SEMICONDUCTOR DEVICES; MATERIALS THEREFOR; ORIGINALS THEREFOR; APPARATUS SPECIALLY ADAPTED THEREFOR
- G03F9/00—Registration or positioning of originals, masks, frames, photographic sheets or textured or patterned surfaces, e.g. automatically
- G03F9/70—Registration or positioning of originals, masks, frames, photographic sheets or textured or patterned surfaces, e.g. automatically for microlithography
Landscapes
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Exposure Of Semiconductors, Excluding Electron Or Ion Beam Exposure (AREA)
- Exposure And Positioning Against Photoresist Photosensitive Materials (AREA)
Abstract
Description
【発明の詳細な説明】
（ａ１上の利用分野）
本発明は被［′ｎ面の基準面からの位置ずれ量（隔り量
）を検出する面位置検出装置に関し、例えば半導体製造
の分野における縮少投影型の露光装置においてウェハ表
面とレチクルパターンの投影結像面との位置ずれを検出
する自動制御装置として用いる場合に好適なものである
。Detailed Description of the Invention (A1 Field of Application) The present invention relates to a surface position detection device for detecting the amount of positional deviation (distance) of a target surface from a reference surface, for example in the field of semiconductor manufacturing. The present invention is suitable for use as an automatic control device for detecting a positional deviation between the wafer surface and the projection image plane of a reticle pattern in a reduction projection type exposure apparatus.
（従来の技術）
従来より半導体製造用の縮少投影型の露光装置において
高解像力を維持する為にはクエへ面上にレチクルパター
ンを高精度に投影させる必要がある、この為にはウェハ
面状態を高精度に検出することが重要となってくる。(Prior Art) Conventionally, in order to maintain high resolution in reduced projection type exposure equipment for semiconductor manufacturing, it is necessary to project a reticle pattern onto the wafer surface with high precision. It is important to detect the state with high accuracy.
第２図は従来の面位置検出装置を備えた縮少投影型の露
光装置の要部概略図である。FIG. 2 is a schematic diagram of the main parts of a reduction projection type exposure apparatus equipped with a conventional surface position detection device.
同図において１は縮少型の投影レンズであり、不図示の
レチクルパターンをウェハ２面上に投影している。又ウ
ェハ２は上下方向及び傾きが副書可能なステージ３にＪ
ｉｌ！されている。５は結像レンズでありレーザやＬＥ
Ｄ等の光源４の光源像をミラー５を介してウェハ２面上
のチップ中心である反射点２ａに結像している。In the figure, reference numeral 1 denotes a reduction type projection lens, which projects a reticle pattern (not shown) onto the wafer 2 surface. In addition, the wafer 2 is placed on a stage 3 that allows subwriting in the vertical direction and inclination.
Il! has been done. 5 is an imaging lens, which is a laser or LE
A light source image of a light source 4 such as D is formed via a mirror 5 on a reflection point 2a which is the center of the chip on the surface of the wafer 2.
ウェハ２で反射した光束はミラー７で反射し、結像レン
ズ８によりポジションセンサー９面上に入射し光源像を
結像している。The light beam reflected by the wafer 2 is reflected by the mirror 7, and is incident on the surface of the position sensor 9 by the imaging lens 8 to form a light source image.
同図に示す面位置検出装置においてはウェハ２面上の光
束の反射点２ａとポジションセンサー９上の入射点９ａ
とを結像関係となるようにし、ウェハ２の上下方向の位
置ずれ量をポジションセンサー９上の光束の入射位置よ
り検出している。In the surface position detection device shown in the figure, the reflection point 2a of the light beam on the wafer 2 surface and the incident point 9a on the position sensor 9
The amount of vertical positional deviation of the wafer 2 is detected from the incident position of the light beam on the position sensor 9.
この面位置検出装置ではウェハ２面上のチップ中心の一
点しか検出できない。This surface position detection device can detect only one point at the center of the chip on the second surface of the wafer.
これに対してチップ中心以外の位置情報を検出する方法
としてウェハ面の傾きを所謂第３図に示すようなコリメ
ータ方式を用いた装置により行う方法がある。On the other hand, as a method of detecting position information other than the center of the chip, there is a method of measuring the inclination of the wafer surface using a device using a so-called collimator system as shown in FIG.
第３図に示すコリメータ方式の装置においては光源４か
らの光束をフーリエ変換レンズｌＯ及びミラー６を介し
、ウェハ２面上のチップ全面に平行光束を入射させ、そ
れからの反射光束をミラー７及びフーリエ変換レンズ１
１を介して光源４の光源像をポジションセンサ９上に結
像させている。このように同図においてはウェハ面２を
瞳としてウェハ２の傾きをポジションセンサ９面上の光
源像の位置ずれとして検出している。In the collimator type device shown in FIG. 3, the light beam from the light source 4 passes through the Fourier transform lens lO and the mirror 6, and the parallel light beam is made incident on the entire surface of the chip on the wafer 2 surface, and the reflected light beam is then sent to the mirror 7 and the Fourier transform lens 1O and the mirror 6. Conversion lens 1
A light source image of the light source 4 is formed on a position sensor 9 via the light source 1 . As described above, in the figure, the wafer surface 2 is used as the pupil, and the inclination of the wafer 2 is detected as a positional shift of the light source image on the position sensor 9 surface.
これよりチップ中心の上下方向の位置ずれ量ΔＺとチッ
プ全体を観測面とした傾き八〇を検出し、ステージ３を
上下方向にΔＺ移動させ、又角度Δθだけ傾きを補正し
てウェハ２の表面とレチクルパターンの投影結像面とを
一致させていた。From this, the vertical positional deviation amount ΔZ of the chip center and the tilt 80 with the entire chip as the observation surface are detected, and the stage 3 is moved vertically by ΔZ, and the tilt is corrected by the angle Δθ, so that the surface of the wafer 2 is and the projection image plane of the reticle pattern.
（発明が解決しようとする問題点）
第２図に示す面位置検出装置ではウェハ面上のチップ中
心の一点しか検出できない為ウェハ面の局所的な形状変
化に大きく影響され、検出精度及び安定性が低いという
問題点があった。(Problems to be Solved by the Invention) Since the surface position detection device shown in FIG. 2 can only detect one point at the center of the chip on the wafer surface, it is greatly affected by local shape changes on the wafer surface, resulting in poor detection accuracy and stability. There was a problem that the value was low.
又第３図に示すコリメータ方式を用いた面位置検出装置
では、例えばウェハ面が第４図（Ａ）に示すような形状
であればチップ中心の上下方向をレチクルパターンの投
影結像面に合わせウニへの傾きを補正すればウェハ面と
レチクルパターンの投影結像面を一致させることができ
る。Furthermore, in the surface position detection device using the collimator method shown in FIG. 3, if the wafer surface has a shape as shown in FIG. By correcting the inclination toward the sea urchin, the wafer surface and the projection imaging plane of the reticle pattern can be made to coincide.
しかしながらウェハ表面が第４図（Ｂ）に示すようなチ
ップ中心に対して偶関数の形状の場合もある。この場合
にはレチクルパターンの投影結像面の設定としては位置
ずれ量を上下方向に振り分けることができるから、例え
ば第４図（］のようにウウェハ面の位置を補正した方が
良いが、般にはウェハ表面の傾きを検出することができ
ない為第４図（Ｂ）の状態でウェハ表面とレチクルパタ
ーンの投影結像面が一致したものと見なしてしまうとい
う問題点があった。However, there are cases where the wafer surface has an even function shape with respect to the chip center as shown in FIG. 4(B). In this case, as the projection image plane of the reticle pattern can be set, the amount of positional deviation can be distributed vertically, so it is better to correct the position of the wafer surface, for example, as shown in Figure 4 (). Since the inclination of the wafer surface cannot be detected, it is assumed that the wafer surface and the projection image plane of the reticle pattern coincide in the state shown in FIG. 4(B).
この他コリメータ方式の装置においてはチップ面内の反
射率の分布が検出精度に大きく影響する為傾きの検出誤
差が生じやすいという問題点があった。In addition, the collimator type device has the problem that the distribution of reflectance within the chip surface greatly affects the detection accuracy, which tends to cause tilt detection errors.
本発明は被観測面（ウェハ面）の局所的な形状変化や局
所的な反射率変化があっても高精度にしかも高い安定性
をもって面位置の状態を検出することのできる、例えば
半導体製造用の露光装置に好適な面位置検出装置の提供
を目的とする。The present invention is capable of detecting the state of the surface position with high precision and high stability even if there is a local shape change or local reflectance change of the surface to be observed (wafer surface). An object of the present invention is to provide a surface position detection device suitable for an exposure apparatus.
（問題点を解決する為の手段）
格子状パターンＧ１を基準面と被観測面に投影させる投
影手段と該基準面と被観測面から反射される該格子状パ
ターンＧｌの像を該格子状パターンＧ１のピッチと異な
るピッチの格子状パターン６２面上に結像させる第１結
像手段と誤格子状パターン６２面上に形成されるモアレ
縞を検出面上に結像させる第２結像手段と該格子状パタ
ーンＧｌを該基準面と該被観測面に投影したときに該検
出面上で得られるモアレ縞の基本周期の位相Ｐ１．Ｐ２
を各々検出する検出手段と該位相Ｐ１．Ｐ２との位相差
から該基準面と該被観測面との位置ずれを求める演算手
段とを有していることである。(Means for Solving the Problem) A projection means for projecting the grid pattern G1 onto a reference surface and an observed surface, and an image of the grid pattern Gl reflected from the reference surface and the observed surface by the grid pattern. A first imaging means for forming an image on the surface of the lattice pattern 62 having a pitch different from the pitch of G1; and a second imaging means for forming an image on the detection surface of moiré fringes formed on the surface of the erroneous lattice pattern 62. The phase P1 of the fundamental period of the moiré fringe obtained on the detection surface when the lattice pattern Gl is projected onto the reference surface and the observed surface. P2
detection means for detecting each phase P1. It has calculation means for determining the positional deviation between the reference surface and the observed surface from the phase difference with P2.
特に本発明では前記被観測面を複数の領域に分割し、該
被観察面に基づくモアレ縞の基本周期の位相Ｐ２と該基
準面に基づく該位相Ｐ１どの位相差を各領域毎に求め該
基準面と各領域毎の位置ずれを求めたことを特徴として
いる。In particular, in the present invention, the observed surface is divided into a plurality of regions, and the phase difference between the phase P2 of the fundamental period of the moiré fringe based on the observed surface and the phase P1 based on the reference surface is determined for each region. It is characterized by determining the positional deviation of each surface and each region.
（実施例）
第１図は本発明の面位置検出装置を半導体製造用の縮少
投影型の露光装置に適用したときの第１実施例の要部概
略図である。(Embodiment) FIG. 1 is a schematic diagram of a main part of a first embodiment in which the surface position detection device of the present invention is applied to a reduction projection type exposure apparatus for semiconductor manufacturing.
同図においてｌは縮少型の投影レンズであり不図示のレ
チクルパターンを被観測面であるウェハ２面上に縮少投
影している。３はステージでありウェハ２と基準面２７
とを載置しており、ステージドライバ２５により水平方
向（Ｘ方向）と上下方向（２方向）及び傾き方向に駆動
制御されている。In the figure, reference numeral 1 denotes a reduction type projection lens, which projects a reticle pattern (not shown) in a reduced size onto two wafer surfaces, which are the surfaces to be observed. 3 is a stage that includes the wafer 2 and the reference surface 27.
The stage driver 25 drives and controls the horizontal direction (X direction), the vertical direction (two directions), and the tilt direction.
２０は照明装置であり、回折格子より成る格子状パター
ンＧｌを角度θ方向から照明している。Reference numeral 20 denotes an illumination device, which illuminates a grating pattern Gl made of a diffraction grating from an angle θ direction.
格子状パターンＧｌは例えば第５図（Ａ）に示すような
とッチＬｌの透過型回折格子より成っており、その大き
さはＬｘｘＬマであり、この大きさはウェハ２面上の観
察領域に相当している。２１は第１結像レンズであり格
子状パターンＧ１を基準面２７及びウェハ２面上にステ
ージ３の水平駆動に伴い順次θ方向から投影結像してい
る。２２は第２結像レンズであり基準面２７及びウェハ
２面から反射されてくる格子状パターンＧｌの像を該格
子状パターンＧｌのピッチＬｌと異なるピッチＬ２を有
する第５図（Ｂ）に示すような透過型回折格子より成る
格子状パターンＧ２面上に結像させている。The grating pattern Gl is made up of a transmission diffraction grating with contacts Ll as shown in FIG. 5(A), for example, and its size is LxxL. is equivalent to Reference numeral 21 denotes a first imaging lens which sequentially projects and images the lattice pattern G1 onto the reference plane 27 and the wafer 2 surface from the θ direction as the stage 3 is driven horizontally. 22 is a second imaging lens, and the image of the lattice pattern Gl reflected from the reference surface 27 and the two wafer surfaces is shown in FIG. 5(B), which has a pitch L2 different from the pitch L1 of the lattice pattern Gl. The image is formed on the surface of a grating pattern G2 consisting of a transmission type diffraction grating.
２３は第３結像レンズであり、格子状パターン６２面上
に形成される、例えば第５図（Ｃ）に示すようなそアレ
縞をＣＣＤ等から成る検出手段２４の検出面２４ａ上に
結像している。Reference numeral 23 denotes a third imaging lens, which focuses the fringes formed on the surface of the lattice pattern 62, for example as shown in FIG. image.
２６は演算手段であり、検出手段２４からのモアレ縞の
基本周期の位相に基づく出力信号を利用して所定の演算
即ち基準面２７とウェハ面２との位置ずれ環を求め、そ
の演算結果に基づく信号をステージドライバ２５に送出
している。26 is a calculation means, which uses the output signal from the detection means 24 based on the phase of the basic period of the moiré fringes to calculate a predetermined calculation, that is, a positional deviation ring between the reference surface 27 and the wafer surface 2, and calculates the positional deviation ring between the reference surface 27 and the wafer surface 2, and calculates the positional deviation ring between the reference surface 27 and the wafer surface 2, and calculates the positional deviation ring between the reference surface 27 and the wafer surface 2, A signal based on this signal is sent to the stage driver 25.
本実施例においては第１結像レンズ２１の投影結像面と
第２結像レンズ２２の物体面そして投影レンズ１による
レチクルパターンの投影結像面が互いに一致するように
構成している。In this embodiment, the projection image plane of the first imaging lens 21, the object plane of the second imaging lens 22, and the projection image plane of the reticle pattern by the projection lens 1 are configured to coincide with each other.
次に本実施例において基準面２７に対する被観測面であ
るウェハ面のＺ方向の位置ずれ量を求める方法について
示す。Next, a method for determining the amount of positional deviation in the Z direction of the wafer surface, which is the observed surface, with respect to the reference surface 27 in this embodiment will be described.
尚、簡単のろに第１．第２．第３結像レンズ２１．２２
．２３の結像倍率を１とし、又格子状パターンＧ１．Ｇ
２のピッチＬ１％Ｌ２と格子状パターンＧｌのＸ方向の
長さＬ８との間には１ ／Ｌ２−１ ／Ｌｌ・５／Ｌ８
・・・・・・・・・・・・・・（りなる関係があるもの
とする。In addition, the first step is simple. Second. Third imaging lens 21.22
．． The imaging magnification of G1.23 is set to 1, and the grid pattern G1. G
The distance between the pitch L1%L2 of 2 and the length L8 in the X direction of the lattice pattern Gl is 1 /L2-1 /Ll・5/L8
・・・・・・・・・・・・・・・(It is assumed that there is a following relationship.
格子状パターンＧ ｌ−ＥのＸ軸上の１点Ｘ１は。One point X1 on the X axis of the grid pattern Gl-E is.
その共役の位置であるウェーハ表面２の位置でのレチク
ルパターンの投影結像面とウェーハ表面の上下方向のズ
レ量Ｚ （ＸＩ 、 Ｙ、 ）により格子状パターンＧ
２上でのその像はδ（ＸＩ）の位置ズレなおこす、ここ
で位置ずれ量δ（Ｘ、）はδ（Ｘｉ） ＝ ２２（ＸＩ
、Ｙ＋） ｃｏｇ（ａ ）＝・・・（２）となる、した
がって格子状パターンＧ１の透過率分布Ｔ、（Ｘ、Ｙ）
は次のようになる。The lattice pattern G is determined by the amount of vertical deviation Z (XI, Y, ) between the projected image plane of the reticle pattern at the conjugate position of the wafer surface 2 and the wafer surface.
The image on 2 causes a displacement of δ(XI), where the amount of displacement δ(X,) is δ(Xi) = 22(XI
, Y+) cog(a)=...(2) Therefore, the transmittance distribution T of the grid pattern G1, (X, Y)
becomes as follows.
Ｔ、（Ｘ、Ｙ） ＝ Ｉ−ｃｏｓ （−Ｌ」」−一）−
（３）格子状パターンＧ２上の強度分布Ｉｔ （Ｘ、
Ｙ）は
となる。T, (X, Y) = I-cos (-L''-1)-
(3) Intensity distribution It (X,
Y) becomes.
また格子状パターンＧ２の透過率分布Ｔ２（ｘ、ｙ）は
次のよう表わせる。Further, the transmittance distribution T2 (x, y) of the grid pattern G2 can be expressed as follows.
２πＸ
Ｔａ（Ｘ、Ｙ） −１−ｃｏｓ （−）””・・・・（
５）Ｌ糞
格子状パターンＧｌの像が格子状パターンＧ２を透過し
、ｆ１４３結像レンズ２３を介し、検出手段２４上に結
像されると例えば第５図（Ｃ）に示すようなモアレ縞が
形成される。このモアレ縞の基本の空間周波数は（１）
式より５／Ｌ、である、この周波数近傍だけの強度分布
１．（Ｘ。2πX Ta(X, Y) −1−cos (−)””・・・(
5) When the image of the L feces grid pattern Gl passes through the grid pattern G2 and is imaged on the detection means 24 via the f143 imaging lens 23, moire fringes as shown in FIG. 5(C) are formed, for example. is formed. The basic spatial frequency of this moire fringe is (1)
From the formula, 5/L, the intensity distribution only in the vicinity of this frequency 1. (X.
Ｙ）は
１、（Ｘ、Ｙ）
においてのデータを夏（Ｘ
）とすると位相は
となる。尚、このようにする為に電気的又は光学的フィ
ルタを通している。Y) is 1, and if the data at (X, Y) is summer (X), the phase will be. In order to do this, it is passed through an electrical or optical filter.
今、Ｙ座標を固定すると（６）式の強度分布は、例えば
第７１３（Ａ）のようになる。Now, if the Y coordinate is fixed, the intensity distribution of equation (6) becomes, for example, as shown in No. 713 (A).
同図において波線は、レチクルパターンの投影結像面と
ウェーハ表面が一致しているときであり、実線か一致し
ていないときを示している。In the figure, the wavy line indicates when the projection image plane of the reticle pattern and the wafer surface match, and the solid line indicates when they do not match.
したがって、例えばクエへ面上の測定領域を５分割にし
て、一致していない時と一致している時の位相差を各々
検知すれば、分割された各領域の平均的な上下位ｎが決
定できる。Therefore, for example, by dividing the measurement area on the surface into 5 parts and detecting the phase difference when they do not match and when they match, the average upper and lower n of each divided area can be determined. can.
位相差を決定するには１分割された領域（Ｘ、（Ｘ □
≦ Ｘｏ 令 −！Ｊ−）となる、従って、
基準面２７を利用し、レチクルパターンの投影結像面と
基準面２７（被検面）が一致している時の位相なあらか
しめ測定しておけば一致していない時の位相を測定する
ことにより位相差が決定できる。また、レチクルパター
ンの投影結像面の位置は予め定められた設計値により決
まっており、この位ｔに基準面を位こづければよい、仮
に、装置の周囲の気圧変動や投影レンズの温度変化によ
り投影結像面の位ｔが変動する時は、気圧センサや露光
量計測などにより周知の方法でその時の像面位置を決定
したり、また周知の投影レンズを介した光ビームによる
面位置検知方法を用いて現在の像面位置に基準面２７を
位置付ければよい。To determine the phase difference, one divided area (X, (X □
≦ Xo order -! J-), therefore,
If you use the reference plane 27 to make a preliminary measurement of the phase when the projection imaging plane of the reticle pattern and the reference plane 27 (test surface) match, you can measure the phase when they do not match. The phase difference can be determined by In addition, the position of the projection image plane of the reticle pattern is determined by a predetermined design value, and it is only necessary to position the reference plane at this point. When the position t of the projection image plane fluctuates due to changes, the image plane position at that time can be determined using a well-known method such as using a barometric pressure sensor or exposure measurement, or the surface position can be determined using a light beam passing through a well-known projection lens. The reference plane 27 may be positioned at the current image plane position using a detection method.
今その位相差Δφを第７図（Ｂ）に示す。The phase difference Δφ is now shown in FIG. 7(B).
位相差と上下方向（Ｚ方向）の位置ずれ量Ｚ（Ｘ、Ｙ）
の関係は（２）式より次のようになる。Phase difference and positional deviation amount Z (X, Y) in the vertical direction (Z direction)
From equation (2), the relationship is as follows.
ここでＸ、Ｙは分割した各領域における代表点である。Here, X and Y are representative points in each divided area.
以上のようにして基準面に対するウニ八表面の各領域に
おける位置ずれ量を求めることができる。In the manner described above, the amount of positional deviation in each area of the surface of the sea urchin with respect to the reference plane can be determined.
本実施例においてＹ座標を変化させれば観測面全体につ
いての位置ずれ量を求めることができる。In this embodiment, by changing the Y coordinate, the amount of positional deviation for the entire observation plane can be determined.
又、（７）式より求められる位置ずれｆｆ１Ｚ（Ｘ、Ｙ
）はその値が分割された１つの領域全体の平均であるた
めウェーハに形成された回路パターンの局所的変動に左
右されない、また観測面をいくつかに分割して面位置を
検出しているので観測面の局所的な反射率の変動にも影
響されない、更にモアレ縞を利用しているので、面位置
の変動による像ずれ量を増大しているので検出感度が高
いという特長を有している。Also, the positional deviation ff1Z (X, Y
) is the average of the entire divided area, so it is not affected by local variations in the circuit pattern formed on the wafer, and since the observation surface is divided into several parts to detect the surface position, It is unaffected by local changes in reflectance on the observation surface, and since it uses moire fringes, the amount of image shift due to changes in surface position is increased, resulting in high detection sensitivity. .
そして本実施例においては第５図（Ｃ）に示すようなモ
アレ縞の位相を分割した各領域毎に読み取ることにより
、ウニ八表面の複数領域における上下方向の位置ずれ量
Ｚ （Ｘｌ 、 Ｙｒ ）を第８図に示すようにして得
ている。In this example, by reading the phase of the moiré fringes as shown in FIG. 5(C) in each divided area, the amount of vertical positional deviation Z (Xl, Yr) in multiple areas on the surface of the sea urchin eight is determined. is obtained as shown in FIG.
又本実施例においては一般に（Ｘ、Ｙ）面に対して小さ
く変位した平面については
Ｚ（Ｘ１、ＹＪ）−ＡＸ＋＋ＢＹｔ＋Ｃとかける。In this embodiment, generally, a plane that is slightly displaced with respect to the (X, Y) plane is multiplied by Z(X1, YJ)-AX++BYt+C.
そこで１次式で求められる値Ｅ
を最小にするＡ、Ｂ、Ｃを決定して現状のウェーハ表面
を平面近似し、その平面と基準平面との隔り量をステー
ジ３の上下方向と傾き方向に駆！１１制御することによ
りて補正している。Therefore, determine A, B, and C that minimize the value E obtained by the linear equation, approximate the current wafer surface as a plane, and calculate the distance between that plane and the reference plane in the vertical and tilt directions of the stage 3. Drive! 11 control.
第９図は本発明の面位置検出装置を第１図の第ｌ実施例
と同様に半導体製造用の縮少投影型の露光装置に適用し
たときの第２実施例の要部概略図である。FIG. 9 is a schematic diagram of the main parts of a second embodiment when the surface position detection device of the present invention is applied to a reduction projection type exposure apparatus for semiconductor manufacturing, similar to the first embodiment of FIG. .
第１図の第１実施例では結像関係のフォーカス許容度の
為、格子状パターンＧ１とウェハ２とを光軸に対して略
垂直な平面内に配置している。In the first embodiment shown in FIG. 1, the lattice pattern G1 and the wafer 2 are arranged in a plane substantially perpendicular to the optical axis for focus tolerance in relation to imaging.
これに対して本実施例では格子状パターンＧｌａからの
回折光のうち±１次回折光のみを選択し、フォーカス許
容度を増し、これによりウェハを光軸に対して垂直な平
面から外して配置し、光学系全体の小型化を図っている
。In contrast, in this example, only the ±1st-order diffracted light from the lattice pattern Gla is selected to increase the focus tolerance, which allows the wafer to be placed out of the plane perpendicular to the optical axis. , we aim to downsize the entire optical system.
第９図において３０は照明装置であり、格子状パターン
Ｇｌａをコヒーレント光で照明している。３１．３２．
３３．３４は各々フーリエ変換レンズであり、このうち
フーリエ変換レンズ３１．３２そしてフーリエ変換レン
ズ３３．３４は各々再回折光学系９１．９２を構成して
いる。In FIG. 9, 30 is an illumination device that illuminates the grid pattern Gla with coherent light. 31.32.
Numerals 33 and 34 are Fourier transform lenses, of which Fourier transform lenses 31 and 33 and 33 and 34 constitute re-diffraction optical systems 91 and 92, respectively.
Ｓ１、Ｓ２はストッパーで所定の回折次数の光束を通過
させており、再回折光学系９１．９２の瞳近傍に配置さ
れている。S1 and S2 are stoppers that allow light beams of a predetermined order of diffraction to pass through, and are arranged near the pupils of the re-diffraction optical systems 91 and 92.
３５は結像レンズであり格子状パターンＧ２ａ面上に生
じたモアレ縞を検出手段２４面上に結像している。Reference numeral 35 denotes an imaging lens which images the moiré fringes generated on the surface of the grid pattern G2a onto the surface of the detection means 24.
本実施例では照明装置３０からコヒーレントな平行光束
を格子状パターンＧｌａに垂直に入射させている。格子
状パターンＧｌａからの射出光束のうち±１次回折光だ
けがフーリエ変換レンズ３１．３２、及びストッパーＳ
ｌから成る再回折光学系９１を通過しミラー６を介しウ
ェーハ面２上に入射される。ウェーへ面２には格子状パ
ターンＧｌａのピッチをＬａとするとＬ ａ ／ ２ｓ
ｉｎθの縞が結像する。In this embodiment, a coherent parallel light beam is made to enter the grid pattern Gla perpendicularly from the illumination device 30. Of the light flux emitted from the grid pattern Gla, only the ±1st-order diffracted light passes through the Fourier transform lens 31, 32 and the stopper S.
The light passes through a re-diffraction optical system 91 consisting of a mirror 6, and is incident on the wafer surface 2 via a mirror 6. If the pitch of the lattice pattern Gla on the wafer surface 2 is La, then La / 2s
A fringe of inθ is imaged.
そしてその縞はフーリエ変換レンズ３３．３４及びそし
てストッパーＳ２より成る再回折光学系９２を通過し格
子状パターンＧ２ａ面上に結像される。The fringes then pass through a re-diffraction optical system 92 consisting of Fourier transform lenses 33, 34 and a stopper S2, and are imaged onto the grid pattern G2a surface.
ここでストッパー３２は格子状パターンＧｌａの±１次
光近傍の光だけを通るようにして不用光をカットしてい
る。Here, the stopper 32 cuts unnecessary light by allowing only light in the vicinity of the ±1st-order light of the lattice pattern Gla to pass through.
ウェーハ表面とレチクルパターンの投影結像面が一致し
ているとき、格子状パターンＧ２ａに結像される縞のピ
ッチはＬ ａ ／ ２となる。When the wafer surface and the projection image plane of the reticle pattern match, the pitch of the stripes imaged on the lattice pattern G2a is L a /2.
今第１実施例の格子状パターンＧｌのピッチＬ、に対し
てＬ ａ ＝２ Ｌ ｌ となるように構成すると検出
手段２４上に結像される備は第１実施例と第２実施例は
同一になり、しかもウェーハ表面の上下方向の変化に対
しても同一になるので面位置検出の処理は第１実施例と
同様になる。Now, if the pitch L of the lattice pattern Gl of the first embodiment is configured so that L a =2 L l , the image formed on the detection means 24 will be the same as that of the first embodiment and the second embodiment. The process of detecting the surface position is the same as in the first embodiment because it is the same even with respect to changes in the vertical direction of the wafer surface.
尚以上の実施例においてウェハ面上を複数の領域に分割
して各領域毎の位置ずれ置を求めたが分割せずに単一の
領域として扱い該領域の位置ずれ糧を求めるようにして
も良いことは当然である。In the above embodiments, the wafer surface was divided into a plurality of regions and the positional deviation for each area was determined, but it is also possible to treat the wafer surface as a single area without dividing it and to calculate the positional deviation of the area. Good things are natural.
以上の各実施例において光学系の色収差を補正し、照明
光を多色化して使用しても良い、そしてこのとき色光に
よって光学系を分離して構成しても良い。In each of the embodiments described above, the chromatic aberration of the optical system may be corrected and the illumination light may be multicolored. In this case, the optical system may be configured to be separated depending on the colored light.
又、格子状パターンＧ１、Ｇ２のピッチをつ工へ面上の
複数に分割した各領域毎によって各々異ならしめて構成
しても良い。Alternatively, the pitches of the lattice patterns G1 and G2 may be made different for each region divided into a plurality of regions on the surface.
この他第２実施例においては格子状パターンＧｌの±１
次光をウェハ面上に入射させているがコヒーレントな２
光束を互いに角度を有してウェハ面上に入射させても良
い。In addition, in the second embodiment, ±1 of the grid pattern Gl
The second light is incident on the wafer surface, but it is coherent 2
The light beams may be incident on the wafer surface at angles to each other.
（発明の効果）
本発明によれば被観測面であるウニ八表面を単−又は複
数の領域に分割し、各領域から生ずるモアレ縞を利用し
上下方向の位置ずれ量を検知し、各領域における位置ず
れ量の平均値を求めることにより、ウニ八表面上に形成
されたパターンの局所的変化や局所的な反射率の変化等
に影響されずにウニ八表面上の面位置を基準面に対して
高精度に検出することができる面位置検出装置を達成す
ることができる。(Effects of the Invention) According to the present invention, the surface of the sea urchin, which is the surface to be observed, is divided into one or more regions, and the amount of vertical positional deviation is detected using the moiré fringes generated from each region. By calculating the average value of the amount of positional deviation at , the surface position on the surface of the sea urchin can be used as a reference plane without being affected by local changes in the pattern formed on the surface of the sea urchin, or changes in local reflectance, etc. However, it is possible to achieve a surface position detection device that can detect the surface position with high accuracy.
第１．第９図は本発明を半導体製造用の調歩投影型の露
光装置に適用したときの第１．第２実施例の要部概略図
、第２、第３図は従来の面位置検出装置の要部概略図、
第４図、第６図はウェハ表面とレチクルパターンの投影
結像面との関係の説明図、第５図は本発明に係る格子状
パターンとモアレ縞の説明図、第７図は本発明に係る検
出手段から（りられるモアレ縞の強度分布の説明図、第
８図は本発明において得られるウェハ面上の位置ずれ徂
の説明図である１図中１は投影レンズ、２０．３０．４
は照明装置、Ｇ１．Ｇ２、Ｇｌａ、Ｇ２ａは格子状パタ
ーン、２１．２２．２３は第１、第２、第３結像レンズ
、２４は検出手段、２は被観測面、２７は基準面、３は
ステージ、２５はステージドライバ、２６は演算手段、
９１．９２は再回折光学系、３１．３２．３３．３４は
フーリエ変換レンズ、Ｓ１、Ｓ２はストッパー、３５は
結像レンズである。1st. FIG. 9 shows the first example when the present invention is applied to a stop-stop projection type exposure apparatus for semiconductor manufacturing. A schematic diagram of the main part of the second embodiment, FIGS. 2 and 3 are schematic diagrams of the main part of a conventional surface position detection device,
FIGS. 4 and 6 are explanatory diagrams of the relationship between the wafer surface and the projection image plane of the reticle pattern, FIG. 5 is an explanatory diagram of the lattice pattern and moiré fringes according to the present invention, and FIG. FIG. 8 is an explanatory diagram of the intensity distribution of moiré fringes obtained from such a detection means, and FIG. 8 is an explanatory diagram of the extent of positional deviation on the wafer surface obtained in the present invention.
is a lighting device, G1. G2, Gla, and G2a are grid patterns, 21, 22, and 23 are first, second, and third imaging lenses, 24 is a detection means, 2 is a surface to be observed, 27 is a reference surface, 3 is a stage, and 25 is a stage driver, 26 is calculation means;
91.92 is a re-diffraction optical system, 31.32.33.34 is a Fourier transform lens, S1 and S2 are stoppers, and 35 is an imaging lens.
Claims (3)
せる投影手段と該基準面と被観測面から反射される該格
子状パターンＧ１の像を該格子状パターンＧ１のピッチ
と異なるピッチの格子状パターンＧ２面上に結像させる
第１結像手段と該格子状パターンＧ２面上に形成される
モアレ縞を検出面上に結像させる第２結像手段と該格子
状パターンＧ１を該基準面と該被観測面に投影したとき
に該検出面上で得られるモアレ縞の基本周期の位相Ｐ１
、Ｐ２を各々検出する検出手段と該位相Ｐ１、Ｐ２との
位相差から該基準面と該被観測面との位置ずれを求める
演算手段とを有していることを特徴とする面位置検出装
置。(1) A projection means for projecting the lattice pattern G1 onto a reference surface and an observed surface, and an image of the lattice pattern G1 reflected from the reference surface and the observed surface at a pitch different from that of the lattice pattern G1. A first image forming means for forming an image on the surface of the grid pattern G2, a second image forming means for forming an image of moiré fringes formed on the surface of the grid pattern G2 on a detection surface, and a second image forming means for forming an image on the surface of the grid pattern G2. Phase P1 of the fundamental period of moiré fringes obtained on the detection surface when projected onto the reference surface and the observed surface
, P2, and calculating means for determining the positional deviation between the reference surface and the observed surface from the phase difference between the phases P1 and P2. .
に基づくモアレ縞の基本周期の位相と該基準面に基づく
該位相Ｐ１との位相差を各領域毎に求め該基準面と各領
域毎の位置ずれを求めたことを特徴とする請求項１記載
の面位置検出装置。(2) The observed surface is divided into a plurality of regions, and the phase difference between the phase of the fundamental period of the moiré fringes based on the observed surface and the phase P1 based on the reference plane is determined for each region. 2. The surface position detection device according to claim 1, wherein the positional deviation is determined for each region.
準面又は被観測面に投影する際、コヒーレントな２光束
を異なる角度で入射させていることを特徴とする請求項
１記載の面位置検出装置。(3) Surface position detection according to claim 1, wherein the projection means allows two coherent beams of light to be incident at different angles when projecting the grid pattern G1 onto the reference surface or the observed surface. Device.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP1008398A JPH02188907A (en) | 1989-01-17 | 1989-01-17 | Face-position detection apparatus |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP1008398A JPH02188907A (en) | 1989-01-17 | 1989-01-17 | Face-position detection apparatus |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| JPH02188907A true JPH02188907A (en) | 1990-07-25 |
Family
ID=11692080
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP1008398A Pending JPH02188907A (en) | 1989-01-17 | 1989-01-17 | Face-position detection apparatus |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPH02188907A (en) |
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO1993006618A1 (en) * | 1991-09-20 | 1993-04-01 | Hitachi, Ltd. | Method and apparatus for forming pattern |
| JPH06188172A (en) * | 1991-03-07 | 1994-07-08 | Philips Gloeilampenfab:Nv | Image formation device |
| JP2012108098A (en) * | 2010-10-20 | 2012-06-07 | Canon Inc | Imaging device using talbot interference and adjustment method of imaging device |
| JP2012146959A (en) * | 2010-11-30 | 2012-08-02 | Asml Netherlands Bv | Measuring method, apparatus, and substrate |
| KR20180097690A (en) * | 2015-12-22 | 2018-08-31 | 에이에스엠엘 네델란즈 비.브이. | Topography measurement system |
-
1989
- 1989-01-17 JP JP1008398A patent/JPH02188907A/en active Pending
Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH06188172A (en) * | 1991-03-07 | 1994-07-08 | Philips Gloeilampenfab:Nv | Image formation device |
| WO1993006618A1 (en) * | 1991-09-20 | 1993-04-01 | Hitachi, Ltd. | Method and apparatus for forming pattern |
| JP2012108098A (en) * | 2010-10-20 | 2012-06-07 | Canon Inc | Imaging device using talbot interference and adjustment method of imaging device |
| US9194825B2 (en) | 2010-10-20 | 2015-11-24 | Canon Kabushiki Kaisha | Imaging apparatus using talbot interference and adjusting method for imaging apparatus |
| JP2012146959A (en) * | 2010-11-30 | 2012-08-02 | Asml Netherlands Bv | Measuring method, apparatus, and substrate |
| KR20180097690A (en) * | 2015-12-22 | 2018-08-31 | 에이에스엠엘 네델란즈 비.브이. | Topography measurement system |
| US11327412B2 (en) | 2015-12-22 | 2022-05-10 | Asml Netherlands B.V. | Topography measurement system |
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