JPS6319001B2 - - Google Patents
Info
- Publication number
- JPS6319001B2 JPS6319001B2 JP7171981A JP7171981A JPS6319001B2 JP S6319001 B2 JPS6319001 B2 JP S6319001B2 JP 7171981 A JP7171981 A JP 7171981A JP 7171981 A JP7171981 A JP 7171981A JP S6319001 B2 JPS6319001 B2 JP S6319001B2
- Authority
- JP
- Japan
- Prior art keywords
- light
- subject
- receiving surface
- lens
- light receiving
- 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
Links
- 238000000034 method Methods 0.000 claims description 21
- 238000007689 inspection Methods 0.000 claims description 7
- 230000003287 optical effect Effects 0.000 claims 2
- 238000001514 detection method Methods 0.000 description 7
- 235000012431 wafers Nutrition 0.000 description 6
- 238000010586 diagram Methods 0.000 description 5
- 230000035945 sensitivity Effects 0.000 description 5
- 229910052710 silicon Inorganic materials 0.000 description 5
- 239000010703 silicon Substances 0.000 description 5
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 description 4
- 238000009826 distribution Methods 0.000 description 4
- 239000004065 semiconductor Substances 0.000 description 4
- 239000000758 substrate Substances 0.000 description 3
- 238000007796 conventional method Methods 0.000 description 1
- 238000005305 interferometry Methods 0.000 description 1
- 150000003376 silicon Chemical class 0.000 description 1
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
- G01N21/84—Systems specially adapted for particular applications
- G01N21/88—Investigating the presence of flaws or contamination
- G01N21/95—Investigating the presence of flaws or contamination characterised by the material or shape of the object to be examined
- G01N21/9501—Semiconductor wafers
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
- G01N21/84—Systems specially adapted for particular applications
- G01N21/88—Investigating the presence of flaws or contamination
- G01N21/8851—Scan or image signal processing specially adapted therefor, e.g. for scan signal adjustment, for detecting different kinds of defects, for compensating for structures, markings, edges
- G01N2021/8887—Scan or image signal processing specially adapted therefor, e.g. for scan signal adjustment, for detecting different kinds of defects, for compensating for structures, markings, edges based on image processing techniques
- G01N2021/889—Scan or image signal processing specially adapted therefor, e.g. for scan signal adjustment, for detecting different kinds of defects, for compensating for structures, markings, edges based on image processing techniques providing a bare video image, i.e. without visual measurement aids
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
- G01N21/84—Systems specially adapted for particular applications
- G01N21/88—Investigating the presence of flaws or contamination
- G01N21/8803—Visual inspection
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)
- Testing Or Measuring Of Semiconductors Or The Like (AREA)
Description
【発明の詳細な説明】
産業上の利用分野
本発明は被検体表面状態の検査装置及び表面の
検査方法に関する。DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to an apparatus for inspecting the surface condition of an object and a method for inspecting the surface.
従来例の構成とその問題点
従来より、鏡面状の半導体基板等の被検体表面
の非接触検査方法として種々の方法や装置が提案
されている。Conventional Structure and Problems Various methods and devices have been proposed as non-contact inspection methods for the surface of a specimen such as a mirror-like semiconductor substrate.
この中で、光やレーザー光の干渉を利用する方
法がある。この方法によれば、0.5μmm程度の段差
や傷などの検出は容易であるが、0.3μmm程度の緩
やかな凹凸は検出し難い欠点を有する。また、細
く絞つたレーザー光を被検体に投射し、その反射
の位置より凹凸を検知する装置もあるがやはり
0.3μmm以下の凹凸は検知し難い。 Among these methods, there is a method that uses interference of light or laser light. According to this method, it is easy to detect steps, scratches, etc. of about 0.5 μm, but it has the disadvantage that it is difficult to detect gentle irregularities of about 0.3 μm. There is also a device that projects a narrowly focused laser beam onto the object and detects irregularities based on the position of the reflection.
It is difficult to detect irregularities smaller than 0.3μmm.
一方、古来より魔鏡として知られている光の反
射を利用する方法があるが、これは感度が高いこ
とが知られている。この方法を第１図を用いて説
明する。同図に以いて以下説明する。光源１１よ
りの光はピンホール１２を通過し、被検体１３で
反射され受光面１４に投影される。この時、被検
体１３表面が完全に平面であれば受光面１４上で
の照度に変化はない。しかし、被検体１３上に凹
み１５があれば、この凹み１５が凹面鏡として作
用することになり、光は被線１６の如く収光され
る。従つて、受光面１４上には１７に示される如
き照度変化が生じる。被検体１３上に凸部がある
場合は、受光面１４上には明暗が反転するが同様
に照度変化が生じる。この方法によれば、0.3μmm
程度の緩かな凹凸は検知可能となるが、この解像
度を得るために光源１１と被検体１３の距離及び
被検体１３と受光面１４の距離を各々３ｍ位とら
ねばならず、装置が大きくなつてしまう。装置が
大となることは受光面１４上での照度が不足した
り、光源１１、被検体１３及び受光面１４間の空
間の光のゆらぎによつて解像度の低下といつた欠
点が生じる。 On the other hand, there is a method that uses the reflection of light, known since ancient times as a magic mirror, but this is known to be highly sensitive. This method will be explained using FIG. This will be explained below with reference to the figure. Light from a light source 11 passes through a pinhole 12, is reflected by a subject 13, and is projected onto a light receiving surface 14. At this time, if the surface of the subject 13 is completely flat, there is no change in the illuminance on the light receiving surface 14. However, if there is a recess 15 on the subject 13, this recess 15 will act as a concave mirror, and the light will be focused like a line 16. Therefore, a change in illuminance as shown at 17 occurs on the light receiving surface 14. When there is a convex portion on the subject 13, the brightness and darkness on the light-receiving surface 14 are reversed, but the illuminance also changes. According to this method, 0.3μmm
Moderate irregularities can be detected, but in order to obtain this resolution, the distance between the light source 11 and the object 13 and the distance between the object 13 and the light-receiving surface 14 must be approximately 3 m each, which increases the size of the device. Put it away. The large size of the apparatus causes drawbacks such as insufficient illuminance on the light receiving surface 14 and a decrease in resolution due to light fluctuations in the space between the light source 11, the subject 13 and the light receiving surface 14.
上記方法より一歩進んだ例として第２図に示す
様なシユリーレン装置を応用した方法が考えられ
ている。同図において、光源１１よりの光はピン
ホール１２を通過し、凸レンズ１８により平行光
線となり被検体１３で反射され、この反射光を凸
レンズ１９により収光される。この収光光線は凸
レンズ１９の焦点拒離上に設けられたナイフエツ
ヂ２０により完全に遮へいされ、受光面１４上に
は光が全く入射されない。しかし、被検体１３上
に凸部２１があると、この凸部２１により平行光
線は散乱され、この散乱光２２の一部は図示の如
くナイフエツヂ２０を越えて受光面１４に照射さ
れる。この方法によれば、散乱光のみが受光面１
４上に結像されるので、上述の魔鏡の方法と同様
に凹凸が明暗となつて現われるが、散乱光のナイ
フエツヂ２０側に曲げられた光は、ナイフエツヂ
２０に停められてしまうために、凹凸による散乱
光の半分しか情報として得られない。また非常に
精密なナイフエツヂ２０が必要である点や、像の
半分が全く影となつてしまう点、装置の大きさも
第１図に示す例と大差ない点等の欠点を有する。 As an example that is one step more advanced than the above method, a method using a Schlieren device as shown in FIG. 2 has been considered. In the figure, light from a light source 11 passes through a pinhole 12, becomes parallel light by a convex lens 18, is reflected by a subject 13, and this reflected light is collected by a convex lens 19. This condensed light beam is completely blocked by a knife edge 20 provided on the focal point of the convex lens 19, and no light is incident on the light receiving surface 14. However, when there is a convex portion 21 on the subject 13, the parallel light rays are scattered by the convex portion 21, and a portion of this scattered light 22 passes over the knife edge 20 and is irradiated onto the light receiving surface 14 as shown in the figure. According to this method, only the scattered light is transmitted to the light receiving surface.
4, the unevenness appears as bright and dark, similar to the magic mirror method described above, but since the scattered light bent toward the knife edge 20 is stopped by the knife edge 20, Only half of the light scattered by the unevenness can be obtained as information. Further, it has disadvantages such as requiring a very precise knife edge 20, half of the image being completely in shadow, and the size of the device being not much different from the example shown in FIG.
更に、被検体１３の鏡面の位置、角度、反りな
どが少しでも狂うと、ナイフエツヂ２０に結ぶべ
き焦点がずれてしまうため、鏡面の位置精度や反
りなどを非常に精度高く取らねばならない上、調
整が非常に微妙で困難であると言う重大な欠点が
ある。 Furthermore, if the position, angle, curvature, etc. of the mirror surface of the subject 13 is even slightly out of order, the focus that should be on the knife edge 20 will shift, so the positional accuracy and curvature of the mirror surface must be very precisely determined, and the adjustment must be made with great precision. There is a serious drawback that it is very subtle and difficult.
発明の目的
本発明は上記欠点にかんがみなされたもので、
簡単な方法により、被検体上の微妙な凹凸を検知
出来、しかも、被検体の全面の観察を可能にしよ
うとする表面の検査装置及び検査方法を提供せん
とするものである。OBJECT OF THE INVENTION The present invention has been made in view of the above-mentioned drawbacks.
It is an object of the present invention to provide a surface inspection device and method that can detect minute irregularities on a subject by a simple method and also enable observation of the entire surface of the subject.
発明の構成
本発明の表面の検査装置及び検査方法は平行線
が照射された被検体と、この被検体からの反射光
を収光する凸レンズ間に形成される空間的像を受
光面に結像させようとするものである。Structure of the Invention The surface inspection apparatus and method of the present invention focuses a spatial image formed between an object to be inspected irradiated with parallel lines and a convex lens that collects reflected light from the object on a light receiving surface. It is an attempt to do so.
実施例の説明
以下、本発明に係る実施例を図面とともに説明
する。第３図は本発明の一実施例を示すもので、
同図ａはその概略構成を示し、同図ｂは動作説明
波形を示す。同図に示すように光源１１よりの光
をレンズ系２３で集光し、ほぼ平行光にし鏡面状
の被検体１３に照射し、この反射光を受光レンズ
系２４で集光した後受光面１４上に投影する。こ
こで受光レンズ２４の焦点像面を被検体１３と一
致せしめず、焦点が被検体１３と受光面１４の間
にくる様に設定する。今、同図Ａの位置に受光レ
ンズ２４の焦点が来るようにすれば、受光面１４
上にはＡの位置の像と同じものが写る。被検体１
３が完全鏡面であればＡの位置には被検体１３に
対応した全くの平面鏡面が現われ、受光面１４上
にはなんの変化も認められない。この時、受光面
１４上の像は第３図ａから明らかなように、被検
体１３に焦点があつていない、いわゆるピンボケ
像である。DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments according to the present invention will be described with reference to the drawings. FIG. 3 shows an embodiment of the present invention.
Figure a shows its schematic configuration, and Figure b shows waveforms for explaining the operation. As shown in the figure, the light from the light source 11 is focused by the lens system 23, turned into almost parallel light, and irradiated onto the mirror-like object 13. The reflected light is focused by the light receiving lens system 24, and then the light receiving surface 14 Project on top. Here, the focal image plane of the light-receiving lens 24 is not set to coincide with the subject 13, but is set so that the focal point is between the subject 13 and the light-receiving surface 14. Now, if the focus of the light-receiving lens 24 is set at the position A in the figure, the light-receiving surface 14
The same thing as the image at position A is shown above. Subject 1
If 3 is a perfect mirror surface, a completely flat mirror surface corresponding to the subject 13 will appear at the position A, and no change will be observed on the light receiving surface 14. At this time, the image on the light-receiving surface 14 is a so-called out-of-focus image in which the object 13 is not in focus, as is clear from FIG. 3a.
しかしながら、被検体１３上に凹部２５があつ
た場合、この凹部２５が凹面鏡となり、光源１１
からの平行光線が散乱される。従つて、平行光線
は第１図に示した同様に照度変化を伴なつて、被
検体１３から光が反射される。この照度分布をも
つた反射光は同図ａのＡ，A′，A″の各位置に対
応して多少の分布変化がある。この状態を同図ｂ
に示す。同図ｂにおいて、Ａ，A′，A″は各々同
図ａのＡ，A′，A″の位置で得られる照度分布で
ある。つまり、凹部２５によりA′→Ａ→A″に従
つて光が集光されるので図示した如き波形が得ら
れる。 However, if there is a recess 25 on the subject 13, this recess 25 becomes a concave mirror, and the light source 11
Parallel rays from the are scattered. Therefore, the parallel light rays are reflected from the subject 13 with the illuminance changing as shown in FIG. The reflected light with this illuminance distribution has a slight distribution change corresponding to each position A, A', A'' in figure a.This state is shown in figure b.
Shown below. In Figure b, A, A', and A'' are illuminance distributions obtained at positions A, A', and A'' in Figure a, respectively. That is, since the light is focused by the recess 25 in the direction A'→A→A'', the waveform shown in the figure is obtained.
以上の如く、本発明に係る本実施例ではレンズ
系２４の焦点を操作すれば自由に受光面１４上の
照度分布が変化するので、被検体１３上の凹凸の
状態が容易に推定出来る。また、図面から推定さ
れる様に被検体１３とＡの位置との距離が長い程
分解能が良くなる。このため、Ａの位置は受光面
１４に近い方が感度が良く望ましい。 As described above, in this embodiment of the present invention, the illuminance distribution on the light-receiving surface 14 can be freely changed by manipulating the focal point of the lens system 24, so the state of irregularities on the subject 13 can be easily estimated. Furthermore, as estimated from the drawings, the longer the distance between the subject 13 and the position A, the better the resolution. Therefore, it is desirable that the position of A be closer to the light-receiving surface 14 for better sensitivity.
本発明では、上記した様に分解能の向上が認め
られている。その原理を第４図を用いて説明す
る。同図において、ａ，ｂ，ｃ，ｆはレンズの中
心Ｏを基点としてそれぞれＯからの距離ａ，ｂ，
ｃ，ｆなる点を示す。第４図ａは第３図ａのＡの
位置での像についての状態で、受光レンズ２４が
ある場合のもの、同図ｂは受光レンズ２４がない
場合のものである。すなわち、同図ａ，ｂにおけ
るａの位置の像（以下この像の高さをl0とする）
は第３図ａのＡの位置の像に対応しており、２４
は第３図ａの受光レンズ２４に対応している。同
図ａにおいて、ａの位置の像は受光レンズ２４
（焦点距離をｆとする）によつて受光面１４上に
投影される。その位置は受光レンズ２４の中心点
Ｏを中心にして各々ａ，ｃである。この時、受光
面１４に投影される実像はｂの位置にある。ａの
位置の像の凹凸に対する光がΔθの角度で散乱さ
れると受光面１４では完全平行光の場合のl1の位
置からΔl1ずれた位置に投影される。 In the present invention, improvement in resolution has been recognized as described above. The principle will be explained using FIG. 4. In the figure, a, b, c, and f are distances a, b, and f from O, respectively, with the center O of the lens as the base point.
Points c and f are shown. FIG. 4a shows the state of the image at position A in FIG. 3a when the light receiving lens 24 is present, and FIG. 4b shows the state when the light receiving lens 24 is not present. In other words, the image at position a in a and b in the same figure (hereinafter, the height of this image is assumed to be l 0 )
corresponds to the image at position A in Figure 3a, and 24
corresponds to the light receiving lens 24 in FIG. 3a. In the figure a, the image at position a is the light receiving lens 24.
(focal length is f) is projected onto the light receiving surface 14. Their positions are a and c, respectively, with the center point O of the light receiving lens 24 as the center. At this time, the real image projected onto the light receiving surface 14 is at position b. When the light corresponding to the unevenness of the image at position a is scattered at an angle of Δθ, it is projected on the light receiving surface 14 at a position shifted by Δl 1 from the position l 1 in the case of perfectly parallel light.
一方、同図ｂにおいて、像l0からの光は平行光
線及び散乱光はそれぞれ受光面１４上ではl0及び
Δl0ずれた位置に投影される。従つて、分解能に
対応する係数はΔl1／l1及びΔl0／l0となり、この
係数が大であれば分解能が良いと言うことにな
る。つまり、レンズ系のある場合とない場合の比
すなわち、Δl1／l1／Δl0／l0を求めると次式の
如くなる。 On the other hand, in FIG. 1B, the parallel light and the scattered light from the image l 0 are projected on the light receiving surface 14 at positions shifted from l 0 and Δl 0 , respectively. Therefore, the coefficients corresponding to the resolution are Δl 1 /l 1 and Δl 0 /l 0 , and the larger the coefficient, the better the resolution. In other words, the ratio between the case with and without the lens system, ie, Δl 1 /l 1 /Δl 0 /l 0 , is determined by the following equation.
Δl1／l1／Δl0／l0＝１＋｜c2／（ａ＋ｃ）（ｆ−ｃ）
｜＞１
〔式中絶対値符号があるのはレンズ系が凹凸両
方を想定したからである。〕
以上の如く、受光レンズ２４を設けることによ
つて拡大率が常に１より大きくなつていることが
分かる。即ち、本発明により分解能が向上してい
ることが示される。Δl 1 /l 1 /Δl 0 /l 0 =1+｜c 2 /(a+c)(f-c)
|>1 [The absolute value sign in the formula is because the lens system is assumed to have both convex and concave surfaces. ] As described above, it can be seen that by providing the light receiving lens 24, the magnification ratio is always greater than 1. That is, it is shown that the present invention improves resolution.
又、このことは次の様にも説明できる。第３図
ｃにおける凹部２５は曲率半径Ｒを有する凹面鏡
と仮定する。この凹面鏡は近似的にR/2に焦点を
結ぶが、前述の受光レンズ２４を通すことによつ
て、さらに短い焦点位置に集光させることができ
る。即ち、相対的には、観察している凹面鏡のＲ
が縮小したようにみえる。このことは、凹みが深
くなつたことに相応している。本装置は、一般的
には曲率半径Ｒとして、１〜100ｍの非常に緩か
で、他の方法では検出できないような凹凸の検出
に特に効果を発揮し、適していると言える。 This can also be explained as follows. It is assumed that the recess 25 in FIG. 3c is a concave mirror having a radius of curvature R. This concave mirror focuses the light approximately at R/2, but by passing the light through the aforementioned light receiving lens 24, the light can be focused at an even shorter focal point. That is, relatively speaking, R of the concave mirror being observed is
appears to have shrunk. This corresponds to the fact that the depression has become deeper. This device can be said to be particularly effective and suitable for detecting irregularities that have a very gentle radius of curvature R of 1 to 100 m and cannot be detected using other methods.
又、同図ｃにおいて、受光面１４上に投影され
る凹部２５の大きさは、受光レンズ２４がない場
合には実線２２のように余り縮少せず、その明暗
差は余り大きくない。従つて、凹部検出感度は余
り高くない。一方、受光レンズ２４がある場合、
焦点距離0によつて異なるが、実線のように大き
く偏光され、例えば、受光面１４がその焦点とな
るuに近い位置にある時は、凹部２５の投像は
明白な輝点（ないしは輝線）となり、従つて、対
応する凹部の検出感度は大巾に向上していること
が明白である。現実にはuは、受光面１４に一
致することは稀であるが、同様に大巾な縮少があ
り、検出感度の向上が生ずるのは明らかである。 In addition, in FIG. 3c, the size of the concave portion 25 projected onto the light-receiving surface 14 does not decrease much as shown by the solid line 22 when the light-receiving lens 24 is not provided, and the difference in brightness is not very large. Therefore, the recess detection sensitivity is not very high. On the other hand, if there is a light receiving lens 24,
Although it varies depending on the focal length 0 , when the light is greatly polarized as shown by the solid line, for example, when the light receiving surface 14 is located close to the focal point u, the projection of the concave portion 25 becomes a clear bright spot (or bright line). Therefore, it is clear that the detection sensitivity of the corresponding recesses has been greatly improved. In reality, u rarely coincides with the light-receiving surface 14, but it is clear that there is a large reduction in the same way, resulting in an improvement in detection sensitivity.
本発明に係る装置は必ずしも第３図に示す如く
２枚のレンズ２３，２４を用いる必要がなく、ハ
ーフミラーを用いることにより一枚のレンズでも
構成出来る。この例を第５図に示す。同図におい
て、光源１１からの光はレンズ２６により平行光
線となり、被検体１３に照射される。被検体１３
により反射された光はレンズ２６を通過し、ハー
フミラー２７で屈折され受光面１４上に投射され
る。この例ではレンズが一枚となるので、装置全
体を小型化出来る。 The device according to the present invention does not necessarily need to use two lenses 23 and 24 as shown in FIG. 3, but can be constructed with a single lens by using a half mirror. An example of this is shown in FIG. In the figure, light from a light source 11 is turned into parallel light by a lens 26, and is irradiated onto a subject 13. Subject 13
The light reflected by the lens 26 passes through the lens 26, is refracted by the half mirror 27, and is projected onto the light receiving surface 14. In this example, since there is only one lens, the entire device can be miniaturized.
第６図は第５図に示す装置により得られたもの
である。この条件として、レンズ２６の焦点距離
１ｍ、光源１１を3W豆電球、受光面１４として
焦点が35cmの撮像管、被検体１３として３インチ
シリコン半導体ウエハーを用いた。また、光源１
１から被検体１３までの距離を1.3ｍ、被検体１
３と受光面までの距離も同程度である。この第６
図の結果から明らかな様に、シリコンウエハー上
に無数の横稿が観察される。このシリコンウエハ
ーの表面状態を触針による検査法（クリステツプ
装置）により測定したところ、２〜３mm毎に2000
〜3000Åの凸部状の稿模様が検出された。この結
果は第６図に示す本発明に係る装置により得られ
たものとよく一致する。 FIG. 6 was obtained using the apparatus shown in FIG. The conditions were as follows: the focal length of the lens 26 was 1 m, the light source 11 was a 3W miniature light bulb, the light receiving surface 14 was an image pickup tube with a focal point of 35 cm, and the object 13 was a 3-inch silicon semiconductor wafer. Also, light source 1
The distance from 1 to subject 13 is 1.3m, subject 1
3 and the distance to the light receiving surface is also about the same. This sixth
As is clear from the results shown in the figure, countless horizontal drafts are observed on the silicon wafer. When the surface condition of this silicon wafer was measured using a stylus inspection method (Cristep device), it was found that 2,000
A convex pattern of ~3000 Å was detected. This result agrees well with that obtained with the device according to the invention shown in FIG.
従来の魔鏡等の方法によれば、以上の様な分解
能を得ようとするためには、被検体と光源、被検
体と受光面の距離を５〜６ｍ取らねばならず、光
源として極めて高いパワーを必要とするばかりで
なく、高感度の受光面が必要であつた。また、こ
れらの装置を全くの暗室内で行なう必要があつ
た。これ等のことを考慮すれば本発明の効果が極
めて大であることが理解される。 According to conventional methods such as magic mirrors, in order to obtain the above resolution, it is necessary to maintain a distance of 5 to 6 meters between the subject and the light source, and between the subject and the light receiving surface, which is extremely expensive for a light source. Not only did it require power, but it also required a highly sensitive light-receiving surface. Furthermore, it was necessary to operate these devices completely in a dark room. Taking these matters into consideration, it will be understood that the effects of the present invention are extremely large.
以上の説明で明らかなように、本発明による装
置は、非常に微少な、緩やかな凹凸をもつ鏡面の
検査に適している。特に、半導体基体として多用
されているシリコンウエハーの検査には特に威力
があることが実証された。一般にシリコンウエハ
ーは、小さいものでも２〜5μｍ、大きなもので
は30μｍに至る反りを有している。レーザーなど
による干渉法ではこの反りによる干渉じまが生
じ、この「しま」と表面の緩やかな第６図に示す
ような「しま」が重畳し、まず、識別不可能であ
る。又、レーザ光の波長からみてもその検出は難
しい。前述したシユリーレン装置によれば、第６
図に示すような「しま」の検出は必ずしも不可能
でないが（空気のゆらぎ等による像の歪が生ずる
が）、前述したように、このような反りは、ナイ
フエツヂを置くべき焦点位置を変化させるため
に、期待される表面状態に対応する像でなく、全
く別の像が生じてしまう欠点がある。 As is clear from the above description, the apparatus according to the present invention is suitable for inspecting mirror surfaces with very minute and gentle irregularities. In particular, it has been demonstrated that this method is especially effective for inspecting silicon wafers, which are often used as semiconductor substrates. In general, silicon wafers have a warpage of 2 to 5 μm even if it is small, and up to 30 μm if it is large. In interferometry using a laser or the like, interference fringes occur due to this warping, and these "stripes" and "stripes" with a gentle surface as shown in FIG. 6 overlap, making them impossible to distinguish. Also, it is difficult to detect it from the viewpoint of the wavelength of the laser beam. According to the Schilleren device described above, the sixth
Although it is not necessarily impossible to detect the "stripes" shown in the figure (image distortion occurs due to air fluctuations, etc.), as mentioned above, such warping changes the focal point where the knife edge should be placed. Therefore, there is a drawback that an image that does not correspond to the expected surface state but a completely different image is generated.
このように本発明の方法によれば、半導体基板
のように、それ自体が全体に緩やかに並んでいて
も全く影響を受けず、微細な表面状態の変化を観
察し得るといつた大きな特徴がある。 As described above, according to the method of the present invention, a major feature is that even if the substrate itself is loosely arranged as a whole, it will not be affected at all, and minute changes in the surface state can be observed. be.
なお、以上の実施例においては、レンズ系を１
枚のレンズを構成する例について述べたが、必ず
しも一枚である必要がなく、数枚で構成しても良
いことは言うまでもない。また、受光レンズを複
数枚のレンズで構成する場合には、受光面に一番
近い凸レンズと被検体との間に焦点像面がある様
にこの凸レンズの焦点を設定すれば良い。 In addition, in the above embodiment, the lens system is
Although an example has been described in which the lens is composed of one lens, it goes without saying that it does not necessarily have to be one lens and may be composed of several lenses. Further, when the light receiving lens is composed of a plurality of lenses, the focus of the convex lens may be set so that the focal image plane is between the convex lens closest to the light receiving surface and the subject.
発明の効果
以上、本発明によれば、極めて簡単な構成によ
り、微小な鏡面上の凹凸が検出出来るので、特に
半導体ウエハー表面等の精密検査にその工業的価
値が高い。Effects of the Invention As described above, according to the present invention, minute irregularities on a mirror surface can be detected with an extremely simple configuration, and therefore the present invention has high industrial value, especially for precision inspection of semiconductor wafer surfaces, etc.
第１図、第２図は従来の検出方法を示す図、第
３図ａ，ｂはそれぞれ本発明の第一実施例の検出
装置の概略構成図、ａの説明波形図、第３図ｃは
検出感度向上の原理を示す補助説明図、第４図
ａ，ｂは本発明の原理を示す説明図、第５図は本
発明の第二実施例を示す図、第６図は第５図に示
す装置で得られた被検体表面写真を示す図であ
る。
１１……光源、１３……被検体、１４……受光
面、２４……受光レンズ、２６……凸レンズ、２
７……ハーフミラー。
1 and 2 are diagrams showing a conventional detection method, FIGS. 3a and 3b are schematic configuration diagrams of a detection device according to the first embodiment of the present invention, a is an explanatory waveform diagram, and FIG. 3c is a diagram showing a conventional detection method. Supplementary explanatory drawings showing the principle of improving detection sensitivity, Fig. 4 a and b are explanatory drawings showing the principle of the present invention, Fig. 5 is a drawing showing the second embodiment of the present invention, Fig. 6 is similar to Fig. 5. FIG. 2 is a diagram showing a photograph of the surface of a subject obtained with the apparatus shown in FIG. 11... Light source, 13... Subject, 14... Light receiving surface, 24... Light receiving lens, 26... Convex lens, 2
7...Half mirror.
Claims (1)
を集光し、この集光された光を被検体表面に照射
する集光レンズと、前記被検体からの反射光を集
光し、この集光された光を受光面に投像する受光
レンズとを備え、前記受光レンズの焦点像面を前
記被検体表面に一致させず、前記被検体表面像
を、前記受光レンズにて前記受光面上に投像さ
せ、前記被検体表面の凹凸を前記受光面上の明暗
像として検出することを特徴とする表面の検査装
置。 ２ 点とみなせる光源から光束を取り出し、この
取り出した光束を集光して被検体に照射し、前記
被検体からの反射光を光学系にて集光して受光面
上に投像するとともに上記光学系の焦点像面が前
記被検体と受光面の間にくるように設定し、前記
投像された被検体の明暗像でもつて前記被検体表
面の凹凸を検出する表面の検査方法。[Scope of Claims] 1. A light emitting source that generates light, a condensing lens that collects light from the light source and irradiates the surface of a subject with the collected light, and a light source that reflects light from the subject. a light-receiving lens that collects light and projects the collected light onto a light-receiving surface; A surface inspection device characterized in that a light receiving lens projects an image onto the light receiving surface, and detects irregularities on the surface of the subject as bright and dark images on the light receiving surface. 2. A light beam is extracted from a light source that can be regarded as a point, the extracted light beam is condensed and irradiated onto a subject, and the reflected light from the subject is condensed by an optical system and projected onto a light-receiving surface, and the above-mentioned A surface inspection method in which a focal image plane of an optical system is set to be between the subject and a light-receiving surface, and irregularities on the surface of the subject are detected using the projected bright and dark images of the subject.
Priority Applications (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP7171981A JPS57186106A (en) | 1981-05-13 | 1981-05-13 | Inspection device for surface |
| US06/348,086 US4547073A (en) | 1981-02-17 | 1982-02-11 | Surface examining apparatus and method |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP7171981A JPS57186106A (en) | 1981-05-13 | 1981-05-13 | Inspection device for surface |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS57186106A JPS57186106A (en) | 1982-11-16 |
| JPS6319001B2 true JPS6319001B2 (en) | 1988-04-21 |
Family
ID=13468605
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP7171981A Granted JPS57186106A (en) | 1981-02-17 | 1981-05-13 | Inspection device for surface |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS57186106A (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2006226804A (en) * | 2005-02-17 | 2006-08-31 | Matsushita Electric Ind Co Ltd | Inspection method of flat display panel |
| JP2006266934A (en) * | 2005-03-24 | 2006-10-05 | Sumitomo Electric Ind Ltd | Method and apparatus for detecting defect in film |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH02151802A (en) * | 1988-12-05 | 1990-06-11 | Matsushita Electric Ind Co Ltd | Specular surface body for projecting latent image, production thereof and method for recognizing this body |
| JP5348765B2 (en) * | 2009-07-21 | 2013-11-20 | 株式会社リューズ | Method and apparatus for inspecting fine irregularities of flat transparent body |
-
1981
- 1981-05-13 JP JP7171981A patent/JPS57186106A/en active Granted
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2006226804A (en) * | 2005-02-17 | 2006-08-31 | Matsushita Electric Ind Co Ltd | Inspection method of flat display panel |
| JP2006266934A (en) * | 2005-03-24 | 2006-10-05 | Sumitomo Electric Ind Ltd | Method and apparatus for detecting defect in film |
Also Published As
| Publication number | Publication date |
|---|---|
| JPS57186106A (en) | 1982-11-16 |
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