JPH063278A - Substrate appearance inspection device - Google Patents

Substrate appearance inspection device

Info

Publication number
JPH063278A
JPH063278A JP4158126A JP15812692A JPH063278A JP H063278 A JPH063278 A JP H063278A JP 4158126 A JP4158126 A JP 4158126A JP 15812692 A JP15812692 A JP 15812692A JP H063278 A JPH063278 A JP H063278A
Authority
JP
Japan
Prior art keywords
substrate
light
inspected
polarized
illumination
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
Application number
JP4158126A
Other languages
Japanese (ja)
Other versions
JP3255709B2 (en
Inventor
Shinichi Tsuchisaka
新一 土坂
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.)
Olympus Corp
Original Assignee
Olympus Optical Co Ltd
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 Olympus Optical Co Ltd filed Critical Olympus Optical Co Ltd
Priority to JP15812692A priority Critical patent/JP3255709B2/en
Publication of JPH063278A publication Critical patent/JPH063278A/en
Application granted granted Critical
Publication of JP3255709B2 publication Critical patent/JP3255709B2/en
Anticipated expiration legal-status Critical
Expired - Fee Related legal-status Critical Current

Links

Abstract

PURPOSE:To provide a substrate appearance inspection device capable of substrate observation at a high S/N ratio by selectively emitting a P-polarized or S-polarized illuminating light evenly to the whole surface of a substrate to be inspected. CONSTITUTION:A substrate appearance inspection device has a light emitting means 3 for emitting a P-polarized or S-polarized illuminating light to the surface of a substrate to be inspected 1; a holding means 5 for holding the substrate 1 to be inspected; and an inclining mechanism 7 for rotating the holding means 5 within a surface vertical to the substrate 1 to be inspected including the illuminating light axis. The light emitting means 3 has a light source 9 for emitting the illuminating light; a fresnel lens 1 for converging the illuminating light emitted from the light source 9'; and a first polarizing plate 14 for selectively giving the optical characteristic of P-polarized light or S-polarized light to the illuminating light guided through the fresnel lens 1 and emitting the resulting light to the substrate surface. The holding means 5 has a second polarizing means 19 for quenching the illuminating light transmitted by the substrate 1 to be inspected.

Description

【発明の詳細な説明】Detailed Description of the Invention

【0001】[0001]

【産業上の利用分野】本発明は、例えば、ウェハ又は液
晶ガラス板等の基板の外観を検査するための基板外観検
査装置に関する。
BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a substrate appearance inspection apparatus for inspecting the appearance of a substrate such as a wafer or a liquid crystal glass plate.

【0002】[0002]

【従来の技術】従来、この種の装置では、被検査基板の
表面に観察用照明光を照射して、基板表面から反射した
反射光の光学的変化を目視観察することによって、基板
表面の外観が検査されている。被検査基板の表面に、ご
み及び傷等の異物が存在している場合、この異物から散
乱光が発生して、基板表面から反射した反射光に強度差
が生じる。観察者は、かかる強度差を検知して基板表面
に存在する異物の目視観察を行う。
2. Description of the Related Art Conventionally, in this type of apparatus, the surface of a substrate to be inspected is irradiated with illumination light for observation, and the optical change of the reflected light reflected from the surface of the substrate is visually observed to give an appearance Is being inspected. When foreign matter such as dust and scratches is present on the surface of the substrate to be inspected, scattered light is generated from the foreign matter and an intensity difference occurs in the reflected light reflected from the substrate surface. The observer detects the difference in strength and visually observes the foreign matter existing on the substrate surface.

【0003】[0003]

【発明が解決しようとする課題】しかしながら、従来の
装置では、偏光観察は行われていなかった。けだし、照
明光路内に偏光板を介在させた場合、基板表面に到達し
得る光量は約30%低下するため、結果、ごみ及び傷等
の異物から発生する散乱光の光強度も低下してしまい目
視による観察が困難になってしまうといった問題が生じ
るからである。
However, the conventional apparatus has not performed polarization observation. However, when a polarizing plate is interposed in the illumination optical path, the amount of light that can reach the substrate surface is reduced by about 30%, and as a result, the light intensity of scattered light generated from foreign matter such as dust and scratches is also reduced. This is because there arises a problem that visual observation becomes difficult.

【0004】また、従来の装置において、被検査基板
は、基板保持台によって照明光軸に対して任意の角度に
回転・揺動するように制御されている。このため、偏光
板を介してP偏光成分を有する偏光照明を照射した場合
でも、被検査基板が回転・揺動して偏光照明の光軸に対
する角度が変化すると、結果的に、基板表面にはP偏光
とS偏光が合成した照明が施されることになり、偏光板
の介在が無意味になってしまうといった問題がある。更
に、偏光照明の場合、基板表面の反射率が照射角度に対
応して大きく変化するため、安定した基板外観目視観察
ができ難いといった問題もある。
Further, in the conventional apparatus, the substrate to be inspected is controlled by the substrate holder so as to rotate and swing at an arbitrary angle with respect to the illumination optical axis. Therefore, even when polarized illumination having a P-polarized light component is irradiated through the polarizing plate, if the substrate to be inspected rotates / swings and the angle of the polarized illumination with respect to the optical axis changes, as a result, Illumination that combines P-polarized light and S-polarized light is performed, and there is a problem that the interposition of a polarizing plate becomes meaningless. Further, in the case of polarized illumination, there is a problem that it is difficult to perform a stable visual observation of the appearance of the substrate because the reflectance of the substrate surface changes greatly depending on the irradiation angle.

【0005】また、従来では、基板表面に存在するごみ
及び傷等の異物から発生する散乱光を(背景光とは、散
乱光を除いた基板表面等から直接反射され反射光をい
う。)いかに際立たせるかに重点が置かれていた。
Further, conventionally, how scattered light generated from foreign matters such as dust and scratches present on the substrate surface (background light means reflected light directly reflected from the substrate surface excluding scattered light). The emphasis was on how to make it stand out.

【0006】このため、従来、異物から発生する散乱光
の量を増加させるための対策としては、被検査基板に照
射される照明光の光量を増加させる点にのみ注目がさ
れ、散乱光と背景光との比(即ち、S/N比)を向上さ
せる点については、全く考慮されていなかった。せいぜ
い、基板保持台の表面を黒く塗って背景光の発生を抑え
る程度であった。
Therefore, conventionally, as a measure for increasing the amount of scattered light generated from a foreign substance, attention has been paid only to increasing the amount of illumination light with which the substrate to be inspected is irradiated. No consideration has been given to improving the ratio with light (that is, the S / N ratio). At best, the surface of the substrate holder was painted black to suppress the generation of background light.

【0007】近年、被検査基板を照明光の光軸に対して
所定角度だけ回動させて、目視による基板表面の外観観
察を行う装置と(特願平3−266307号明細書参
照)、適宜選択的に光学的特性の異なる照明光を基板表
面全体に斑なく照射して、基板表面の外観観察を行う装
置と(特願平4−31922号明細書参照)が開発され
ている。これら装置では、被検査基板の表面全体に照明
光を照射して、S/N比の高い基板表面観察を行うこと
が要求されているが、今だ実用化には至っていない。
In recent years, an apparatus for visually observing the appearance of the substrate surface by rotating the substrate to be inspected by a predetermined angle with respect to the optical axis of the illumination light (see Japanese Patent Application No. 3-266307), as appropriate. An apparatus (see Japanese Patent Application No. 4-31922) for selectively illuminating the entire substrate surface with illumination light having different optical characteristics and observing the appearance of the substrate surface has been developed. In these devices, it is required to illuminate the entire surface of the substrate to be inspected with illumination light to observe the substrate surface with a high S / N ratio, but it has not yet been put to practical use.

【0008】本発明は、このような要求に対応するため
になされ、その目的は、被検査基板の表面全体に斑なく
P偏光又はS偏光の照明光を選択的に照射して、S/N
比の高い基板観察を行うことができる基板外観検査装置
を提供することにある。
The present invention has been made in order to meet such a demand, and an object thereof is to selectively irradiate the entire surface of the substrate to be inspected with P-polarized or S-polarized illuminating light to obtain S / N.
It is an object of the present invention to provide a substrate visual inspection apparatus capable of observing substrates with a high ratio.

【0009】[0009]

【課題を解決するための手段】このような目的を達成す
るために、本発明の基板外観検査装置は、被検査基板を
照明するための照明光を発光する光源と、この光源から
発光した前記照明光をP偏光又はS偏光に選択的に変換
する第1の偏光手段と、この第1の偏光手段を介して偏
光が施された前記照明光の光路中に前記被検査基板を保
持する保持台と、 S偏光照明の場合に、前記被検査基
板の表面に存在する異物から発生した散乱光のみを透過
する第2の偏光手段と、前記保持台を前記照明光軸を含
み前記被検査基板に垂直な面内で回動させる傾斜機構と
を備える。
In order to achieve such an object, the substrate appearance inspection apparatus of the present invention comprises a light source that emits illumination light for illuminating a substrate to be inspected, and the light source that emits the illumination light. First polarization means for selectively converting illumination light into P-polarized light or S-polarized light, and holding for holding the inspected substrate in the optical path of the illumination light polarized by the first polarization means. A base, a second polarization means for transmitting only scattered light generated from a foreign substance present on the surface of the substrate to be inspected in the case of S-polarized illumination, and the substrate to be inspected including the holding table including the illumination optical axis. And a tilting mechanism for rotating in a plane perpendicular to the plane.

【0010】[0010]

【作用】光源から発光した照明光は、第1の偏光手段を
介してP偏光又はS偏光に選択的に変換された後、保持
台上に保持された被検査基板に照射される。P、S各偏
光は、ガラス表面での反射、異物の散乱光に関して異な
る特性を持っているので、この特性を利用し、P偏光照
明では、散乱光と背景光とのSN比を高め、S偏光の場
合は、第2の偏光手段により、異物の散乱光のみを取り
出す。
The illumination light emitted from the light source is selectively converted into P-polarized light or S-polarized light through the first polarizing means, and then is irradiated onto the substrate to be inspected held on the holding table. Since each of P and S polarized light has different characteristics with respect to the reflection on the glass surface and the scattered light of a foreign substance, this characteristic is used to increase the SN ratio between the scattered light and the background light in P polarized illumination, In the case of polarized light, only the scattered light of the foreign matter is extracted by the second polarizing means.

【0011】[0011]

【実施例】以下、本発明の一実施例に係る基板外観検査
装置について、図1ないし図4を参照して説明する。な
お、本実施例の装置には、ガラス製の被検査基板がセッ
トされているものとする。まず、P偏光とS偏光の観察
用照明光の特性について図2ないし図4を参照して説明
する。
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A substrate appearance inspection apparatus according to an embodiment of the present invention will be described below with reference to FIGS. It should be noted that a glass substrate to be inspected is set in the apparatus of this embodiment. First, the characteristics of P-polarized and S-polarized illumination light for observation will be described with reference to FIGS. 2 to 4.

【0012】図2(a)には、空気中で被検査基板1
(屈折率n=1.5)の滑らかなガラス表面にP偏光又
はS偏光の照明光を照射した際の入射角(θ)と反射率
(r)との関係が示されている。
FIG. 2A shows the substrate 1 to be inspected in the air.
The relationship between the incident angle (θ) and the reflectance (r) when P-polarized or S-polarized illumination light is applied to a smooth glass surface (refractive index n = 1.5) is shown.

【0013】ここで、図2(b)及び図3(a)に示す
ように、P偏光の照明光を被検査基板1に照射しつつ被
検査基板1を傾斜させて、照明光軸に対する角度を変化
させていくと、反射角(θ1 )と屈折角(θ2 )とで成
す角が90°になるとき反射率は0(ゼロ)となり、 tanθ=n (n=1.5) …(1) の関係がある。このときの入射角(θ)をブリュースタ
角(θB )という。図4は、P、S偏光がごみ及び傷等
の異物Cに当った場合の散乱光の分布である。
Here, as shown in FIGS. 2 (b) and 3 (a), the substrate 1 to be inspected is tilted while irradiating the substrate 1 to be inspected with P-polarized illumination light to form an angle with respect to the illumination optical axis. When the angle formed by the reflection angle (θ 1 ) and the refraction angle (θ 2 ) becomes 90 °, the reflectance becomes 0 (zero), and tan θ = n (n = 1.5) ... There is a relationship of (1). The incident angle (θ) at this time is called Brewster's angle (θ B ). FIG. 4 is a distribution of scattered light when P and S polarized light strikes a foreign substance C such as dust and scratches.

【0014】このように、照明光がブリュースタ角(θ
B )で被検査基板1の表面に入射した場合、被検査基板
1の表面に存在するごみ及び傷等の異物Cから発生する
散乱光のみが観察者の目Dに届き、他の照明光は、基板
表面を透過して被検査基板1に吸収される。このため、
観察者の目Dには、基板表面に存在する異物Cの像のみ
が投影される。
In this way, the illumination light is reflected by the Brewster angle (θ
When incident on the surface of the substrate 1 to be inspected in B ), only scattered light generated from the foreign matter C existing on the surface of the substrate 1 to be inspected such as dust and scratches reaches the eyes D of the observer, and other illumination light , And is absorbed by the substrate 1 to be inspected. For this reason,
Only the image of the foreign matter C existing on the substrate surface is projected on the eyes D of the observer.

【0015】しかし、図3(a)及び図4に示すよう
に、ブリュースタ角(θB )は、実際、式(1)を用い
て演算すると、55°程度の入射角となる。このため、
図4の散乱分布と観察者の目Dの位置から、異物Cから
発生する散乱光は観察者に見づらいものとなる。
However, as shown in FIGS. 3A and 4, the Brewster angle (θ B ) is actually an incident angle of about 55 ° when calculated by using the equation (1). For this reason,
From the scattering distribution and the position of the observer's eyes D in FIG. 4, the scattered light generated from the foreign matter C is difficult for the observer to see.

【0016】一方、図3(b)及び図4に示すように、
ブリュースタ角(θB )よりも小さい角度(θ3 )の場
合、室内光及び背景光の光があっても、異物Cから発生
する散乱光の分布が観察者側に強くなり、且つ、ガラス
表面反射が自然光照明より小さいので、異物Cのコント
ラストが上昇する。
On the other hand, as shown in FIGS. 3 (b) and 4,
When the angle (θ 3 ) is smaller than the Brewster angle (θ B ), the distribution of scattered light generated from the foreign matter C becomes strong on the observer side even if there is room light and background light, and the glass is Since the surface reflection is smaller than that of natural light illumination, the contrast of the foreign matter C is increased.

【0017】また、背景光としては、被検査基板1の裏
面から反射した裏面反射光Eも、その一因となるが、図
2(b)に示すように、被検査基板1の表面に照射され
る照明光の入射角(θ)に対する裏面反射率は、図2
(a)に示された特性と同一特性となる。
As the background light, the back surface reflected light E reflected from the back surface of the substrate 1 to be inspected contributes to the background light, but as shown in FIG. The back surface reflectance with respect to the incident angle (θ) of the illumination light is shown in FIG.
The characteristics are the same as those shown in (a).

【0018】次に、S偏光の照明光を被検査基板1に照
射した場合、図2(a)、(b)に示すように、入射角
(θ)が小さいうちはP偏光と変わらないが、入射角
(θ)が15°を越える辺りから、P偏光に比べて反射
率(r)が上昇する。また、図4より基板表面に存在す
る異物Cから発生する散乱光の散乱強度も上昇する。
Next, when the substrate 1 to be inspected is irradiated with S-polarized illumination light, as shown in FIGS. 2A and 2B, while the incident angle (θ) is small, it is the same as P-polarized light. From around the angle of incidence (θ) exceeding 15 °, the reflectance (r) increases as compared with P-polarized light. Further, as shown in FIG. 4, the scattering intensity of scattered light generated from the foreign matter C existing on the substrate surface also increases.

【0019】しかし、保持板表面から反射する背景光の
光強度も上昇して、結果的に、視野の背景が明るくなり
異物Cのコントラストが低下すると共に、観察者の目D
には不要な強い光が届き始める。
However, the light intensity of the background light reflected from the surface of the holding plate also rises, and as a result, the background of the field of view becomes brighter and the contrast of the foreign matter C decreases, and the eyes D of the observer.
Unnecessary strong light begins to reach.

【0020】このようなP偏光及びS偏光の特性を考慮
すると、観察用照明光としてP偏光を用いた方が、被検
査基板1の表面に存在するごみ及び傷等の異物Cから発
生する散乱光を他の光に対して際立たせることができる
点でS偏光よりも有利である。しかし、P偏光は、散乱
光の散乱強度がS偏光の場合に比べて弱くなる点で不利
である。
Considering such characteristics of P-polarized light and S-polarized light, when P-polarized light is used as the illumination light for observation, scattering generated from foreign matter C such as dust and scratches present on the surface of the substrate 1 to be inspected. It is advantageous over S-polarized light in that it allows light to be distinguished from other light. However, P-polarized light is disadvantageous in that the scattering intensity of scattered light is weaker than that of S-polarized light.

【0021】そこで、本実施例の基板外観検査装置は、
被検査基板1の表面に存在するごみ及び傷等の異物Cか
ら発生する散乱光を他の光に対して際立たせて、異物C
の検出能力を向上させるために、P偏光及びS偏光の互
いの利点を生かした基板観察が行えるように構成されて
いる。図1には、本実施例の基板外観検査装置の構成が
概略的に示されている。
Therefore, the board appearance inspection apparatus of this embodiment is
The scattered light generated from the foreign matter C such as dust and scratches present on the surface of the substrate 1 to be inspected is made to stand out against other light, and the foreign matter C
In order to improve the detection ability of P polarized light and S polarized light, it is possible to observe the substrate by utilizing the mutual advantages of P polarized light and S polarized light. FIG. 1 schematically shows the configuration of the substrate visual inspection apparatus of this embodiment.

【0022】図1に示すように、本実施例の基板外観検
査装置は、被検査基板1の表面にP偏光又はS偏光の照
明光を照射する照射手段3と、被検査基板1を保持する
保持手段5と、この保持手段5を照明光軸を含み被検査
基板1に垂直な面内で回動させる傾斜機構7とを備えて
いる。
As shown in FIG. 1, the substrate visual inspection apparatus of this embodiment holds the substrate 1 to be inspected and an irradiation means 3 for irradiating the surface of the substrate 1 to be inspected with illumination light of P polarization or S polarization. The holding means 5 and the tilting mechanism 7 for rotating the holding means 5 in a plane including the illumination optical axis and perpendicular to the substrate 1 to be inspected are provided.

【0023】照射手段3は、照明光を発光する光源9
と、この光源9から発光された照明光を集束させるフレ
ネルレンズ11と、このフレネルレンズ11を介して導
光された照明光に対して所定の光学的特性を与えて被検
査基板1の表面に照明する第1の偏光板13とを備えて
いる。この第1の偏光板13は、受光した照明光に対し
て適宜選択的にP偏光又はS偏光の光学的特性を与える
機能を有している。
The irradiation means 3 is a light source 9 which emits illumination light.
A Fresnel lens 11 for converging the illumination light emitted from the light source 9, and a predetermined optical characteristic to the illumination light guided through the Fresnel lens 11 to provide a predetermined optical characteristic on the surface of the substrate 1 to be inspected. And a first polarizing plate 13 for illuminating. The first polarizing plate 13 has a function of selectively and selectively imparting P-polarized or S-polarized optical characteristics to the received illumination light.

【0024】保持手段3は、被検査基板1よりも広範囲
な保持面15aを有する保持台15と、この保持台15
の保持面15a上に突設された複数の吸着保持部17と
を備えている。被検査基板1を保持台15上に載置する
と、被検査基板1は、その裏面に当接した複数の吸着保
持部17によって吸着保持される。この結果、被検査基
板1は、保持台15上に固定される。
The holding means 3 has a holding base 15 having a holding surface 15a having a wider area than that of the substrate 1 to be inspected, and the holding base 15.
And a plurality of suction holding portions 17 protruding from the holding surface 15a. When the substrate 1 to be inspected is placed on the holding table 15, the substrate 1 to be inspected is suction-held by the plurality of suction-holding portions 17 that are in contact with the back surface thereof. As a result, the substrate 1 to be inspected is fixed on the holding table 15.

【0025】傾斜機構7は、保持台15の一端側に取り
付けられており、かかる一端側を中心に保持台15の他
端側を図中矢印A方向に揺動させる機能を有している。
傾斜機構7を駆動して保持台15を揺動させることによ
って、保持台15上に固定された被検査基板1は、照明
光軸Bに対して所定の角度(具体的には、0度〜40度
の範囲)に傾斜される。
The tilting mechanism 7 is attached to one end side of the holding table 15 and has a function of swinging the other end side of the holding table 15 in the direction of arrow A in the figure around the one end side.
By driving the tilting mechanism 7 and swinging the holding table 15, the substrate 1 to be inspected fixed on the holding table 15 has a predetermined angle with respect to the illumination optical axis B (specifically, 0 ° to 0 °). It is tilted in the range of 40 degrees).

【0026】また、本実施例の基板外観検査装置は、保
持台15の保持面15a上に第2の偏光板19を備えて
いる。第2の偏光板19は、被検査基板1を透過した照
明光の偏光方向に対してクロスニコルとなるように、調
節可能に構成されている。
Further, the substrate visual inspection apparatus of this embodiment is provided with the second polarizing plate 19 on the holding surface 15a of the holding table 15. The second polarizing plate 19 is configured to be adjustable so that the second polarizing plate 19 has a crossed Nicol with respect to the polarization direction of the illumination light that has passed through the inspected substrate 1.

【0027】更に、本実施例の基板外観検査装置は、観
察者の目Dの前に第3の偏光板21を備えている。第3
の偏光板21は、被検査基板1の表面及び裏面から反射
した反射光の偏光方向に対してクロスニコルとなるよう
に、調節可能に構成されている。
Further, the substrate visual inspection apparatus of this embodiment is provided with the third polarizing plate 21 in front of the eyes D of the observer. Third
The polarizing plate 21 is configured to be adjustable so as to be crossed Nicol with respect to the polarization direction of the reflected light reflected from the front surface and the back surface of the substrate 1 to be inspected.

【0028】以下、本実施例の基板外観検査装置の動作
について図1を参照して説明する。まず、P偏光の照明
光を用いて基板外観の検査を行う場合、図1に示すよう
に、光源9から発光された照明光は、フレネルレンズ1
1及び第1の偏光板13を介してP偏光に変換されて、
被検査基板1の表面に照射される。このとき、傾斜機構
7を駆動させて保持台15の傾きを図中矢印A方向に変
化させて、被検査基板1の照明光軸Bに対する傾斜角度
を変化させる。
The operation of the substrate visual inspection apparatus of this embodiment will be described below with reference to FIG. First, when the substrate appearance is inspected using P-polarized illumination light, the illumination light emitted from the light source 9 is the Fresnel lens 1 as shown in FIG.
Is converted into P polarized light through the first and first polarizing plates 13,
The surface of the substrate 1 to be inspected is irradiated. At this time, the tilting mechanism 7 is driven to change the tilt of the holding table 15 in the direction of arrow A in the figure, and the tilt angle of the substrate 1 to be inspected with respect to the illumination optical axis B is changed.

【0029】被検査基板1からは、基板表面に存在する
ごみ及び傷等の異物Cから発生する散乱光と、基板表面
から直接反射した反射光と、基板裏面から反射した裏面
反射光E(図2(b)参照)とが発生する。
From the substrate 1 to be inspected, scattered light generated from foreign matters C such as dust and scratches present on the substrate surface, reflected light directly reflected from the substrate surface, and back surface reflected light E reflected from the back surface of the substrate (Fig. 2 (b)) occurs.

【0030】また、被検査基板1を透過した照明光は、
保持台15上に設けられた第2の偏光板19に照射され
る。このとき、照明光の偏光方向に対してクロスニコル
(かかる場合は、P偏光に対してクロスニコル)に第2
の偏光板19を調節する。この結果、被検査基板1を透
過した照明光は、かかる第2の偏光板19で打消され、
保持台15の保持面15aからの背景光の発生が防止さ
れる。
The illumination light transmitted through the substrate 1 to be inspected is
The second polarizing plate 19 provided on the holding table 15 is irradiated. At this time, the crossed Nicols (in this case, the crossed Nicols with respect to the P polarized light) with respect to the polarization direction of the illumination light
The polarizing plate 19 of is adjusted. As a result, the illumination light transmitted through the inspected substrate 1 is canceled by the second polarizing plate 19,
Generation of background light from the holding surface 15a of the holding table 15 is prevented.

【0031】本実施例の基板外観検査装置には、観察者
の目Dの前に第3の偏光板21が配置されており、この
第3の偏光板21を被検査基板1から反射した反射光
(基板表面及び裏面の双方からの反射光)の偏光方向
(P偏光)に対してクロスニコルに調節する。この結
果、被検査基板1の表面及び裏面から反射した反射光
は、かかる第3の偏光板21で遮光され、観察者の目D
には、被検査基板1の表面に存在する異物Cから発生し
た散乱光のみが投影される。
In the substrate visual inspection apparatus of this embodiment, a third polarizing plate 21 is arranged in front of the eyes D of the observer, and the third polarizing plate 21 is reflected from the substrate 1 to be inspected. The polarization direction (P-polarized light) of light (reflected light from both the front and back surfaces of the substrate) is adjusted to be crossed Nicols. As a result, the reflected light reflected from the front surface and the back surface of the substrate 1 to be inspected is shielded by the third polarizing plate 21 and the eyes D of the observer.
Only the scattered light generated from the foreign substance C existing on the surface of the substrate 1 to be inspected is projected on the screen.

【0032】従って、P偏光照明では、観察に無益な被
検査基板1の表面、裏面及び保持台15の保持面15a
から反射する反射光を遮光することができるため、観察
者の目Dに優しく且つごみ及び傷等の異物Cから発生す
る散乱光を際立たせることができる。この結果、被検査
基板1の表面に存在する異物Cの検出能力を向上させる
ことができる。
Therefore, in the P-polarized illumination, the front and back surfaces of the substrate 1 to be inspected and the holding surface 15a of the holding table 15 are useless for observation.
Since it is possible to block the reflected light reflected from the, it is possible to make the scattered light generated from the foreign matter C such as dust and scratches gentle to the eyes D of the observer. As a result, it is possible to improve the ability to detect the foreign substance C existing on the surface of the substrate 1 to be inspected.

【0033】更に、P偏光照明として集束光照明を用い
て、反射光の集光点近傍に目Dを位置付けた場合でも、
反射光が直接目に入らないため、目Dのくらみを引き起
こすことなくS/N比の高い基板観察を行うことができ
る。
Further, even when the focused light illumination is used as the P-polarized illumination and the eye D is positioned near the condensing point of the reflected light,
Since the reflected light does not directly enter the eyes, it is possible to observe the substrate with a high S / N ratio without causing the eyes D to be blurred.

【0034】なお、P偏光の照明光を用いた場合、被検
査基板1に照射される照明光の入射角(θ)が一定の範
囲内(15°ないし40°程度)となるように保持台1
5を制御することによって、散乱光の光強度とガラス表
面からの反射光の比を大きくできるため、第3の偏光板
21は必ずしも必要ではない。
When P-polarized illumination light is used, the holding table is arranged so that the incident angle (θ) of the illumination light applied to the substrate 1 to be inspected is within a certain range (about 15 ° to 40 °). 1
Since the ratio of the light intensity of scattered light to the light reflected from the glass surface can be increased by controlling 5, the third polarizing plate 21 is not always necessary.

【0035】次に、S偏光の照明光を用いて基板外観の
検査を行う場合、図1に示すように、光源9から発光さ
れた照明光は、フレネルレンズ11及び第1の偏光板1
3を介してS偏光に変換されて、被検査基板1の表面に
照射される。このとき、傾斜機構7を駆動させて保持台
15の傾きを図中矢印A方向に変化させて、被検査基板
1の照明光軸Bに対する傾斜角度を変化させる。
Next, when the substrate appearance is inspected using S-polarized illumination light, as shown in FIG. 1, the illumination light emitted from the light source 9 is the Fresnel lens 11 and the first polarizing plate 1.
It is converted into S-polarized light via 3 and is irradiated onto the surface of the substrate 1 to be inspected. At this time, the tilting mechanism 7 is driven to change the tilt of the holding table 15 in the direction of arrow A in the figure, and the tilt angle of the substrate 1 to be inspected with respect to the illumination optical axis B is changed.

【0036】被検査基板1からは、基板表面に存在する
ごみ及び傷等の異物Cから発生する散乱光と、基板表面
から直接反射した反射光と、基板裏面から反射した裏面
反射光E(図2(b)参照)とが発生する。
From the substrate 1 to be inspected, scattered light generated from foreign substances C such as dust and scratches present on the substrate surface, reflected light directly reflected from the substrate surface, and back surface reflected light E reflected from the back surface of the substrate (Fig. 2 (b)) occurs.

【0037】S偏光の照明光を用いた場合、基板表面に
存在するごみ及び傷等の異物Cから発生する散乱光の光
強度はP偏光の照明光を用いた場合に比べて上昇する
が、反射光及び裏面反射光Eの夫々の光強度も上昇す
る。
When the S-polarized illumination light is used, the light intensity of the scattered light generated from the foreign matter C such as dust and scratches existing on the substrate surface is higher than that when the P-polarized illumination light is used. The respective light intensities of the reflected light and the back surface reflected light E also increase.

【0038】また、被検査基板1を透過した照明光は、
保持台15上に設けられた第2の偏光板19に照射され
る。このとき、照明光の偏光方向に対してクロスニコル
(かかる場合は、S偏光に対してクロスニコル)に第2
の偏光板19を調節する。この結果、被検査基板1を透
過した照明光は、かかる第2の偏光板19で打消され、
保持台15の保持面15aからの背景光の発生が防止さ
れる。
The illumination light transmitted through the substrate 1 to be inspected is
The second polarizing plate 19 provided on the holding table 15 is irradiated. At this time, the second cross-Nicol (in this case, the cross-Nicol with respect to S-polarized light) polarization direction of the illumination light
The polarizing plate 19 of is adjusted. As a result, the illumination light transmitted through the inspected substrate 1 is canceled by the second polarizing plate 19,
Generation of background light from the holding surface 15a of the holding table 15 is prevented.

【0039】本実施例の基板外観検査装置には、観察者
の目Dの前に第3の偏光板21が配置されており、この
第3の偏光板21を被検査基板1から反射した反射光
(基板表面及び裏面の双方からの反射光)の偏光方向
(S偏光)に対してクロスニコルに調節する。この結
果、被検査基板1の表面及び裏面から反射した反射光
は、かかる第3の偏光板21で遮光され、観察者の目D
には、被検査基板1の表面に存在する異物Cから発生し
た強い光強度を有するP成分散乱光のみが投影される。
In the substrate visual inspection apparatus of this embodiment, the third polarizing plate 21 is arranged in front of the eyes D of the observer, and the third polarizing plate 21 is reflected by the substrate 1 to be inspected. The polarization direction (S-polarized light) of light (reflected light from both the front surface and the back surface of the substrate) is adjusted to be crossed Nicols. As a result, the reflected light reflected from the front surface and the back surface of the substrate 1 to be inspected is shielded by the third polarizing plate 21 and the eyes D of the observer.
Only the P-component scattered light having a strong light intensity generated from the foreign matter C existing on the surface of the substrate 1 to be inspected is projected onto.

【0040】かかる場合、観察者の目Dには、真暗な視
野の中にごみ及び傷等の異物Cが浮き上がったように写
る。この結果、被検査基板1の表面に存在する異物Cに
対してS/N比の高い基板観察を行うができる。
In such a case, the observer's eyes D appear as if foreign matter C such as dust and scratches had risen in the dark field of view. As a result, it is possible to observe the substrate having a high S / N ratio with respect to the foreign matter C existing on the surface of the substrate 1 to be inspected.

【0041】このように、本実施例の基板外観検査装置
は、被検査基板の表面全体に斑なくP偏光又はS偏光の
照明光を選択的に照射して、S/N比の高い基板観察を
行うことができる。
As described above, the substrate visual inspection apparatus of this embodiment selectively irradiates the entire surface of the substrate to be inspected with P-polarized or S-polarized illumination light to observe the substrate having a high S / N ratio. It can be performed.

【0042】[0042]

【発明の効果】本発明の基板外観検査装置は、被検査基
板の表面に存在する異物から発生した散乱光のみを透過
する第2の偏光手段を備えているため、被検査基板の表
面全体に斑なくP偏光又はS偏光の照明光を選択的に照
射してS/N比の高い基板観察を行うことができる。
Since the substrate visual inspection apparatus of the present invention comprises the second polarizing means for transmitting only the scattered light generated from the foreign matter existing on the surface of the substrate to be inspected, the entire surface of the substrate to be inspected is inspected. It is possible to selectively irradiate P-polarized light or S-polarized illumination light without unevenness to observe a substrate having a high S / N ratio.

【図面の簡単な説明】[Brief description of drawings]

【図1】本発明の一実施例に係る基板外観検査装置の構
成を概略的に示す図。
FIG. 1 is a diagram schematically showing a configuration of a board appearance inspection apparatus according to an embodiment of the present invention.

【図2】(a)は、空気中で被検査基板の滑らかなガラ
ス表面にP又はS偏光の照明光を照射した際の入射角
(θ)と反射率(r)との関係を示す図、(b)は、被
検査基板に対して照射された照明光の導光経路を示す
図。
FIG. 2A is a diagram showing a relationship between an incident angle (θ) and a reflectance (r) when P or S polarized illumination light is applied to a smooth glass surface of a substrate to be inspected in air. , (B) are views showing the light guide path of the illumination light with which the substrate to be inspected is irradiated.

【図3】(a)(b)は、共に、P偏光の照明光を被検
査基板に照射しつつ被検査基板を傾斜させて、照明光軸
に対する角度を変化させた際に、ごみ及び傷等の異物C
から発生する散乱光の発生状態を示す図。
3A and 3B show dust and scratches when the inspection substrate is tilted while the inspection light substrate is irradiated with P-polarized illumination light and the angle with respect to the illumination optical axis is changed. Foreign material C
The figure which shows the generation | occurrence | production state of the scattered light generate | occur | produced from.

【図4】P偏光及びS偏光をごみ及び傷等の異物に照射
した際に発生する散乱光の散乱強度を示す図。
FIG. 4 is a diagram showing the scattering intensity of scattered light generated when P-polarized light and S-polarized light are applied to foreign matter such as dust and scratches.

【符号の説明】[Explanation of symbols]

1…被検査基板、3…照射手段、5…保持手段、7…傾
斜機構、9…光源、11…フレネルレンズ、13…第1
の偏光板、19…第2の偏光板。
1 ... Inspected substrate, 3 ... Irradiation means, 5 ... Holding means, 7 ... Inclination mechanism, 9 ... Light source, 11 ... Fresnel lens, 13 ... First
Polarizing plate, 19 ... Second polarizing plate.

Claims (2)

【特許請求の範囲】[Claims] 【請求項1】 被検査基板を照明するための照明光を発
光する光源と、 この光源から発光した前記照明光を前記被検査基板に対
しP偏光又はS偏光に選択的に変換する第1の偏光手段
と、 この第1の偏光手段を介して偏光が施された前記照明光
の光路中に前記被検査基板を保持する保持台と、 前記保持台を前記照明光軸を含み前記被検査基板に垂直
な面内で回動させる傾斜機構と、を備えることを特徴と
する基板外観検査装置。
1. A light source that emits illumination light for illuminating a substrate to be inspected, and a first light source for selectively converting the illumination light emitted from the light source into P-polarized light or S-polarized light with respect to the substrate to be inspected. Polarizing means, a holder for holding the substrate to be inspected in the optical path of the illumination light polarized by the first polarizing means, and the substrate to be inspected including the holder for the illumination optical axis. And a tilting mechanism for rotating the board in a plane perpendicular to the substrate visual inspection apparatus.
【請求項2】 前記保持台には、前記被検査基板を透過
した照明光を消光させる第2の偏光手段が設けられてい
ることを特徴とする請求項1に記載の基板外観検査装
置。
2. The substrate visual inspection apparatus according to claim 1, wherein the holding table is provided with a second polarization unit that extinguishes the illumination light transmitted through the substrate to be inspected.
JP15812692A 1992-06-17 1992-06-17 Board appearance inspection device Expired - Fee Related JP3255709B2 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP15812692A JP3255709B2 (en) 1992-06-17 1992-06-17 Board appearance inspection device

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP15812692A JP3255709B2 (en) 1992-06-17 1992-06-17 Board appearance inspection device

Related Child Applications (1)

Application Number Title Priority Date Filing Date
JP2001157593A Division JP3523848B2 (en) 2001-05-25 2001-05-25 Lighting equipment for visual inspection

Publications (2)

Publication Number Publication Date
JPH063278A true JPH063278A (en) 1994-01-11
JP3255709B2 JP3255709B2 (en) 2002-02-12

Family

ID=15664861

Family Applications (1)

Application Number Title Priority Date Filing Date
JP15812692A Expired - Fee Related JP3255709B2 (en) 1992-06-17 1992-06-17 Board appearance inspection device

Country Status (1)

Country Link
JP (1) JP3255709B2 (en)

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JP2000097864A (en) * 1998-09-21 2000-04-07 Olympus Optical Co Ltd Floodlight device for visual inspection
WO2005040776A1 (en) * 2003-10-27 2005-05-06 Nikon Corporation Surface inspection device and surface inspection method
JP2005180939A (en) * 2003-12-16 2005-07-07 Lasertec Corp Optical apparatus, inspection device and inspection method
KR100898781B1 (en) * 2002-06-14 2009-05-20 엘지디스플레이 주식회사 Visual inspection apparatus and liquid crystal display manufacturing method using it
JP2018021805A (en) * 2016-08-03 2018-02-08 キヤノン株式会社 Lighting apparatus

Cited By (12)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2000097864A (en) * 1998-09-21 2000-04-07 Olympus Optical Co Ltd Floodlight device for visual inspection
JP4576006B2 (en) * 1998-09-21 2010-11-04 オリンパス株式会社 Projection device for visual inspection
KR100898781B1 (en) * 2002-06-14 2009-05-20 엘지디스플레이 주식회사 Visual inspection apparatus and liquid crystal display manufacturing method using it
WO2005040776A1 (en) * 2003-10-27 2005-05-06 Nikon Corporation Surface inspection device and surface inspection method
US7298471B2 (en) 2003-10-27 2007-11-20 Nikon Corporation Surface inspection apparatus and surface inspection method
JPWO2005040776A1 (en) * 2003-10-27 2007-11-22 株式会社ニコン Surface inspection apparatus and surface inspection method
JP4552859B2 (en) * 2003-10-27 2010-09-29 株式会社ニコン Surface inspection apparatus and surface inspection method
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JP2018021805A (en) * 2016-08-03 2018-02-08 キヤノン株式会社 Lighting apparatus

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