JPS6321855B2 - - Google Patents

Info

Publication number
JPS6321855B2
JPS6321855B2 JP55144058A JP14405880A JPS6321855B2 JP S6321855 B2 JPS6321855 B2 JP S6321855B2 JP 55144058 A JP55144058 A JP 55144058A JP 14405880 A JP14405880 A JP 14405880A JP S6321855 B2 JPS6321855 B2 JP S6321855B2
Authority
JP
Japan
Prior art keywords
light
bright
field illumination
dark
field
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
Application number
JP55144058A
Other languages
Japanese (ja)
Other versions
JPS5767844A (en
Inventor
Shoichi Tanimoto
Kazunori Imamura
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Nikon Corp
Original Assignee
Nippon Kogaku KK
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Nippon Kogaku KK filed Critical Nippon Kogaku KK
Priority to JP14405880A priority Critical patent/JPS5767844A/en
Publication of JPS5767844A publication Critical patent/JPS5767844A/en
Publication of JPS6321855B2 publication Critical patent/JPS6321855B2/ja
Granted legal-status Critical Current

Links

Classifications

    • GPHYSICS
    • G01MEASURING; TESTING
    • G01NINVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
    • G01N21/00Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
    • G01N21/84Systems specially adapted for particular applications
    • G01N21/88Investigating the presence of flaws or contamination

Landscapes

  • Physics & Mathematics (AREA)
  • Health & Medical Sciences (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Chemical & Material Sciences (AREA)
  • Analytical Chemistry (AREA)
  • Biochemistry (AREA)
  • General Health & Medical Sciences (AREA)
  • General Physics & Mathematics (AREA)
  • Immunology (AREA)
  • Pathology (AREA)
  • Length Measuring Devices By Optical Means (AREA)
  • Investigating Materials By The Use Of Optical Means Adapted For Particular Applications (AREA)
  • Testing Or Measuring Of Semiconductors Or The Like (AREA)

Description

【発明の詳細な説明】 本発明は被検査物の表面の検査装置に関するも
のである。さらに詳しく言えば、LSI製造に用い
られるフオトマスクやシリコンウエハ(以下ウエ
ハと略す)の表面の回路パターン観察及び異物の
目視検査を行なう装置に関するものである。
DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an apparatus for inspecting the surface of an object to be inspected. More specifically, the present invention relates to an apparatus for observing circuit patterns on the surface of photomasks and silicon wafers (hereinafter referred to as wafers) used in LSI manufacturing and visually inspecting foreign objects.

従来より、フオトマスクやウエハ上に形成され
た回路パターンが望むような外観を呈しているか
どうかを検査するのに最も一般に行なわれてきた
方法は、光学顕微鏡により目視で観察することで
ある。特に、回路パターンの欠陥ではなく、塵等
の異物を検出する場合は、暗視野照明により異物
や回路パターンのエツジ部のみを明るい像として
観察していた。
Conventionally, the most common method for inspecting whether a circuit pattern formed on a photomask or wafer has a desired appearance is to visually observe it using an optical microscope. In particular, when detecting foreign matter such as dust rather than a defect in a circuit pattern, dark field illumination is used to observe only the foreign matter or the edge of the circuit pattern as a bright image.

一方、フオトマスクのみについては、周期的に
並んだチツプのうちの2つを比較する等の方法に
より自動的に回路パターンの欠陥検査がなされて
いたが、回路パターンそのものの欠陥であるの
か、異物が付着しているのみであるのかの判定は
自動的にはできず、加えて装置価格も高く、簡便
に使用できるものではなかつた。またウエハ表面
のパターン欠陥を自動的に検出する技術はまだ完
成しておらず、異物を検出する自動装置は複雑で
大型なものとなつて、パターンの観察装置と兼用
することはできなかつた。
On the other hand, for photomasks only, the circuit pattern was automatically inspected for defects by comparing two of the chips lined up periodically. It is not possible to automatically determine whether there is only adhesion, and in addition, the equipment is expensive and cannot be used easily. Furthermore, the technology for automatically detecting pattern defects on the surface of a wafer has not yet been perfected, and automatic devices for detecting foreign objects are complex and large, and cannot be used as pattern observation devices.

以上のような理由で暗視野照明による顕微鏡観
察が異物検出方法として最も普及しているのであ
るが、この方法では回路パターンのエツジも明る
い線として見えてしまい、異物の明るい像もエツ
ジの明線が視野に散在する中に埋もれて、ややも
すると見逃がしやすいという欠点があつた。そこ
で、通常のパターンの観察は明視野の照明で行な
い、異物検出の時のみ暗視野照明を行なうことが
考えられるが、切り替える不便さがあつた。
For the reasons mentioned above, microscopic observation using dark-field illumination is the most popular method for detecting foreign objects, but with this method, the edges of the circuit pattern also appear as bright lines, and the bright image of the foreign object also shows the bright lines of the edges. The disadvantage was that it was easy to miss because the images were scattered in the field of vision. Therefore, it is conceivable to use bright-field illumination for normal pattern observation and use dark-field illumination only when detecting foreign objects, but this is inconvenient to switch.

本発明においては、このような欠点を解消する
ために通常のパターン観察は明視野照明で行なう
とともに、異物検出の時には暗視野照明を使用す
ることにしたのであり、しかもこのことを簡単な
装置で切替えの不便さを伴なうことなく、取付良
好性を確保しつつ達成することを目的とする。
In the present invention, in order to eliminate these drawbacks, we decided to perform normal pattern observation using bright field illumination and use dark field illumination when detecting foreign objects, and furthermore, we have decided to use dark field illumination for foreign object detection. The purpose is to achieve this while ensuring good installation quality without causing inconvenience in switching.

上記目的を達成するために、本発明において
は、表面に所定のパターンを有する被検査物を観
察光学系を用いて観察し、該表面に付着した異物
を検査する装置において、前記被検査物の表面を
第1の分光特性の光で明視野照明する明視野照明
手段と、該第1の分光特性の光の照射された前記
表面を、前記第1の分光特性と異なる第2の分光
特性の光で同時に暗視野照明する暗視野照明手段
とを有し、前記第1の分光特性の光と前記第2の
分光特性の光との強度関係を調節し、前記観察光
学系により前記被検査物のパターンの明視野像と
前記異物の暗視野像とを色彩を変えて同時に観察
するようにしたのである。
In order to achieve the above object, the present invention provides an apparatus for observing an object to be inspected having a predetermined pattern on its surface using an observation optical system and inspecting foreign matter adhering to the surface of the object to be inspected. bright-field illumination means for bright-field illuminating a surface with light having a first spectral characteristic; and bright-field illumination means for illuminating a surface with light having a first spectral characteristic; dark field illumination means for simultaneously illuminating the dark field with light, adjusting the intensity relationship between the light of the first spectral characteristic and the light of the second spectral characteristic, and controlling the intensity relationship between the light of the first spectral characteristic and the light of the second spectral characteristic, and The bright-field image of the pattern and the dark-field image of the foreign object were simultaneously observed in different colors.

以下、本発明の実施例を示す図面に基づいて詳
述する。
Hereinafter, embodiments of the present invention will be described in detail based on the drawings.

第1図において被検査物の表面(被検査面)1
には回路パターン等が描画され、対物レンズ2、
プリズム7及び接眼鏡8によつて光学顕微鏡の如
き観察光学系が構成され、ランプ3、コンデンサ
レンズ2、フイルタ5及びハーフミラー6によつ
てランプ3の光を観察視野12に導く光学系を有
する観察用照明手段が構成されている。レーザ光
源9から発せられるレーザビーム10は反射鏡1
1で反射されて、観察視野12に導かれる。
In Figure 1, the surface of the object to be inspected (surface to be inspected) 1
A circuit pattern etc. is drawn on the objective lens 2,
The prism 7 and the eyepiece 8 constitute an observation optical system such as an optical microscope, and the lamp 3, the condenser lens 2, the filter 5, and the half mirror 6 have an optical system that guides the light from the lamp 3 to the observation field 12. Observation illumination means is configured. A laser beam 10 emitted from a laser light source 9 is reflected by a reflecting mirror 1
1 and guided to the observation field 12.

レーザ光源9は単色性の良い光源として暗視野
照明用に用いられ、フイルタ5はランプ3の光を
レーザ光源と異なるスペクトル分布(分光特性)
の光にして、その光で明視野照明するように用い
られる。回路パターンは上記の明視野照明の顕微
鏡によつて観察され、レジストパターン形成工程
やエツチング工程が検査される。これらの検査時
に、表面に異物の付着している被検査物の部分が
回路パターンと共に顕微鏡視野12に入つた場
合、異物によるレーザ光の散乱強度は明視野照明
によるパターンの観察像の強度よりも強く、明視
野像の中に違つた色の像として明瞭に観察され
る。すなわち、回路パターンのエツジにより散乱
されたレーザ光による像は明視野照明によるパタ
ーンの像よりも弱く、明視野像の中に埋もれてし
まうように、レーザビームの強度と明視野照明の
強度の関係を定めればよい。この状態はレーザビ
ーム10又は明視野照明の強度を調節することに
よつて容易に達成される。
The laser light source 9 is used as a monochromatic light source for dark field illumination, and the filter 5 converts the light from the lamp 3 into a spectral distribution (spectral characteristic) different from that of the laser light source.
This light is used for bright field illumination. The circuit pattern is observed using the above-mentioned bright field illumination microscope, and the resist pattern forming process and etching process are inspected. During these inspections, if a part of the object to be inspected that has foreign matter attached to its surface enters the microscope field of view 12 along with the circuit pattern, the intensity of the laser light scattered by the foreign matter will be higher than the intensity of the observed image of the pattern using bright field illumination. It is intense and can be clearly observed as a different color image in a bright field image. In other words, the relationship between the intensity of the laser beam and the intensity of bright-field illumination is such that the image created by the laser beam scattered by the edges of the circuit pattern is weaker than the image of the pattern created by bright-field illumination and is buried in the bright-field image. All you have to do is determine. This condition is easily achieved by adjusting the intensity of the laser beam 10 or bright field illumination.

レーザ光源として波長633nmのHe−Neレーザ
を用いた場合、明視野照明は緑色を用いると、補
色の関係によつて回路パターン像と異物とを最も
明瞭に区別して観察することができる。さらに、
回路パターン像が緑色なので、目の被労も起りに
くい。
When a He--Ne laser with a wavelength of 633 nm is used as the laser light source, using green as the bright field illumination allows the circuit pattern image and the foreign matter to be most clearly distinguished and observed due to the relationship of complementary colors. moreover,
Since the circuit pattern image is green, it is less likely to cause eye strain.

しかし一般に明視野照明光は緑色でなくてもよ
く、暗視野照明光のスペクトル分布と異なつてい
て、色彩の違いとして認識できればよい。
However, in general, bright-field illumination light does not have to be green; it is sufficient that the spectral distribution is different from that of dark-field illumination light and can be recognized as a difference in color.

また上記実施例では暗視野照明光源をレーザ光
源9として記述したが、強度の強い光源であれば
よく、高輝度のLED、他のランプ等でもよい。
そのようなレーザ光源以外の光源においては、そ
の照明時のスペクトルが明視野照明のスペクトル
と違つており、色彩の区別ができればよい。この
ような光源のうち単色性が悪いものについては適
当なフイルターを用いればよい。
Further, in the above embodiment, the dark-field illumination light source is described as the laser light source 9, but any light source with high intensity may be used, such as a high-intensity LED or other lamp.
In a light source other than such a laser light source, the spectrum during illumination is different from the spectrum of bright field illumination, and it is sufficient if the color can be distinguished. For such light sources with poor monochromaticity, an appropriate filter may be used.

以上の実施例は落射型の明視野照明を行なつた
場合のものであつたが、透過型の明視野照明に対
しても本発明を適用することができる。この場
合、暗視野の照明は第1図と同様に反射型でも行
なえるし、透過型で観察用対物レンズの開口に直
接透過光が入射しないような配置にして行なうこ
ともできる。このような透過型の照明はフオトマ
スク等の検査に有用である。
Although the above embodiments are those in which epi-illuminated bright-field illumination is performed, the present invention can also be applied to transmission-type bright-field illumination. In this case, the dark field illumination can be performed by a reflection type as in FIG. 1, or by a transmission type and arranged so that the transmitted light does not directly enter the aperture of the observation objective lens. Such transmission type illumination is useful for inspecting photomasks and the like.

また、以上の実施例では接眼鏡を通して肉眼で
像を観察するように記述したが、暗視野照明の強
い光が被検査物の表面の傾きによつて入射し、肉
眼に入つて眼に傷害を与える恐れがある場合に
は、最低2色の撮像ができるカラーテレビカメラ
により撮像し、テレビ画面を見るようにした方が
良い。
Furthermore, although the above embodiment described the image being observed with the naked eye through an eyepiece, strong light from dark field illumination may enter the naked eye due to the inclination of the surface of the object to be inspected, causing damage to the eye. If there is a risk of this happening, it is better to use a color television camera that can capture images in at least two colors and view the image on a television screen.

尚、実施例では、明視野用及び暗視野用それぞ
れに照明用光源を設けたが、特に輝度の強いラン
プを用いれば、そのランプの光をフイルタによつ
て2色に分けて明視野及び暗視野照明することも
可能である。
In the example, a light source for illumination was provided for bright field and dark field, but if a lamp with particularly strong brightness is used, the light from the lamp is divided into two colors by a filter and used for bright field and dark field. Field illumination is also possible.

以上のように本発明によれば、普通の顕微鏡で
明視野照明観察を行なうと同時に、異物の検出及
び観察が行なえる利点があり、装置の構成が簡単
であるから、すでに販売されて使用中の顕微鏡に
も取付けが可能であるという利点もある。
As described above, the present invention has the advantage of being able to detect and observe foreign objects at the same time as performing bright field illumination observation with an ordinary microscope, and the device has a simple configuration, so it is already on the market and in use. Another advantage is that it can be attached to other types of microscopes.

更に本発明は、LSI製造用のフオトマスクやシ
リコンウエハの表面検査はもとより、これらのみ
ならず滑らかな表面を有し、微小な異物の付着が
問題となる物体の表検査にも有用である。
Furthermore, the present invention is useful not only for surface inspection of photomasks and silicon wafers for LSI manufacturing, but also for surface inspection of objects that have smooth surfaces and where attachment of minute foreign matter is a problem.

【図面の簡単な説明】[Brief explanation of the drawing]

図面は本発明の実施例の説明図である。 主要部分の符号の説明、1……被検査物、3…
…ランプ、5……フイルタ、8……接眼鏡、9…
…レーザ光源、10……レーザビーム、12……
観察視野。
The drawings are explanatory diagrams of embodiments of the present invention. Explanation of symbols of main parts, 1...Object to be inspected, 3...
...Lamp, 5...Filter, 8...Eyepiece, 9...
...Laser light source, 10...Laser beam, 12...
observation field.

Claims (1)

【特許請求の範囲】 1 表面に所定のパターンを有する被検査物を観
察光学系を用いて観察し、該表面に付着した異物
を検査する装置において、 前記被検査物の表面を第1の分光特性の光で明
視野照明する明視野照明手段と、該第1の分光特
性の光の照射された前記表面を、前記第1の分光
特性と異なる第2の分光特性の光で同時に暗視野
照明する暗視野照明手段とを有し、前記第1の分
光特性の光と前記第2の分光特性の光との強度関
係を調節し、前記観察光学系により前記被検査物
のパターンの明視野像と前記異物の暗視野像とを
色彩を変えて同時に観察することを特徴とする表
面検査装置。 2 前記明視野照明手段からの光と、前記暗視野
照明手段からの光とを補色の関係に定めた特許請
求の範囲第1項に記載の表面検査装置。 3 前記暗視野照明手段は、ほぼコーヒレントな
レーザ光を発生するレーザ光源である特許請求の
範囲第2項に記載の表面検査装置。
[Scope of Claims] 1. In an apparatus for observing an object to be inspected having a predetermined pattern on its surface using an observation optical system and inspecting foreign matter adhering to the surface, the surface of the object to be inspected is subjected to a first spectroscopy. bright-field illumination means for bright-field illuminating with light of a characteristic, and dark-field illumination of the surface irradiated with light of the first spectral characteristic with light of a second spectral characteristic different from the first spectral characteristic; dark-field illumination means for adjusting the intensity relationship between the light having the first spectral characteristic and the light having the second spectral characteristic, and producing a bright-field image of the pattern of the object to be inspected by the observation optical system. and a dark-field image of the foreign matter at the same time in different colors. 2. The surface inspection apparatus according to claim 1, wherein the light from the bright field illumination means and the light from the dark field illumination means are set in a complementary color relationship. 3. The surface inspection apparatus according to claim 2, wherein the dark field illumination means is a laser light source that generates substantially coherent laser light.
JP14405880A 1980-10-15 1980-10-15 Surface inspecting device Granted JPS5767844A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP14405880A JPS5767844A (en) 1980-10-15 1980-10-15 Surface inspecting device

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP14405880A JPS5767844A (en) 1980-10-15 1980-10-15 Surface inspecting device

Publications (2)

Publication Number Publication Date
JPS5767844A JPS5767844A (en) 1982-04-24
JPS6321855B2 true JPS6321855B2 (en) 1988-05-09

Family

ID=15353326

Family Applications (1)

Application Number Title Priority Date Filing Date
JP14405880A Granted JPS5767844A (en) 1980-10-15 1980-10-15 Surface inspecting device

Country Status (1)

Country Link
JP (1) JPS5767844A (en)

Families Citing this family (13)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS59200908A (en) * 1983-04-28 1984-11-14 Hitachi Ltd Method and apparatus for lighting wafer
JPS6129712A (en) * 1984-07-23 1986-02-10 Hitachi Ltd Method and device for detecting defect of fine pattern
JPH0613963B2 (en) * 1984-09-07 1994-02-23 株式会社日立製作所 Surface defect inspection method
JPH061179B2 (en) * 1985-01-31 1994-01-05 株式会社日立製作所 Defect inspection method and apparatus
JPH061183B2 (en) * 1985-10-03 1994-01-05 株式会社日立製作所 Defect inspection method and apparatus
JPS6285809A (en) * 1985-10-11 1987-04-20 Mitsubishi Electric Corp Lighting device for pattern recognition
JP2512050Y2 (en) * 1986-02-18 1996-09-25 株式会社 東京精密 Observation device in non-contact detection device
FR2665259B1 (en) * 1990-07-27 1992-10-16 Giat Ind Sa METHOD AND APPARATUS FOR DETERMINING THE QUALITY OF OPTICAL PARTS.
JP2981117B2 (en) * 1993-06-08 1999-11-22 三菱電機株式会社 Method for detecting and inspecting minute foreign matter, scanning probe microscope used therefor, and method for producing semiconductor element or liquid crystal display element using the same
JP2827843B2 (en) * 1993-10-18 1998-11-25 村田機械株式会社 Package dirt inspection method
US6407373B1 (en) * 1999-06-15 2002-06-18 Applied Materials, Inc. Apparatus and method for reviewing defects on an object
US7782452B2 (en) * 2007-08-31 2010-08-24 Kla-Tencor Technologies Corp. Systems and method for simultaneously inspecting a specimen with two distinct channels
WO2022270015A1 (en) * 2021-06-21 2022-12-29 ソニーグループ株式会社 Biological specimen observation device and biological specimen observation system

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS53102792A (en) * 1977-02-21 1978-09-07 Hitachi Ltd Simultaneous inspecting apparatus of inside and outside of body to be inspected
JPS54101389A (en) * 1978-01-27 1979-08-09 Hitachi Ltd Foreign matter inspecting method

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS53102792A (en) * 1977-02-21 1978-09-07 Hitachi Ltd Simultaneous inspecting apparatus of inside and outside of body to be inspected
JPS54101389A (en) * 1978-01-27 1979-08-09 Hitachi Ltd Foreign matter inspecting method

Also Published As

Publication number Publication date
JPS5767844A (en) 1982-04-24

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