JPH0528499B2 - - Google Patents
Info
- Publication number
- JPH0528499B2 JPH0528499B2 JP26090885A JP26090885A JPH0528499B2 JP H0528499 B2 JPH0528499 B2 JP H0528499B2 JP 26090885 A JP26090885 A JP 26090885A JP 26090885 A JP26090885 A JP 26090885A JP H0528499 B2 JPH0528499 B2 JP H0528499B2
- Authority
- JP
- Japan
- Prior art keywords
- image
- center
- gravity
- detected
- 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.)
- Expired - Lifetime
Links
- 230000005484 gravity Effects 0.000 claims description 21
- 238000001514 detection method Methods 0.000 claims 1
- 235000012431 wafers Nutrition 0.000 description 28
- 230000007547 defect Effects 0.000 description 5
- 238000010586 diagram Methods 0.000 description 5
- 238000000034 method Methods 0.000 description 3
- 239000008186 active pharmaceutical agent Substances 0.000 description 2
- 238000007796 conventional method Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 230000006870 function Effects 0.000 description 1
- 238000005259 measurement Methods 0.000 description 1
- 238000000926 separation method Methods 0.000 description 1
Description
（産業上の利用分野）
本発明はウエハー等の被検出体（以下ワークと
いう）の切欠損傷を検出する画像処理装置に関す
る。
（従来技術）
ウエハーの外形の欠陥（欠落）を検出する方法
は目視にてウエハーの外形の欠陥をウエハーの面
積のみで判定することにより行なわれている。
（発明が解決しようとする問題点）
上記従来の方法では目視にてウエハーの外形の
欠陥をウエハーの面積のみで判定するので、ウエ
ハーの小さな欠落を判別できない。例えば半径ｒ
の公差＋０mm−0.5mmの５インチウエハーの場合
公差内での面積差は
πr2−πr′2＝π｛（127mm／２）2
−（127mm／２−0.5mm）2｝＝２cm2
となり、２cm2＝14×14mm以下の欠落を判定するこ
とができない。これはウエハー以外のワークの外
形の欠落を検出しようとする場合でも同様であ
る。
（問題点を解決するための手段）
本発明は第１図に示すようにワークの画像の面
積及び重心を算出する手段１と、上記重心からワ
ークの画像外縁までの半径方向距離を測定する手
段２と、上記半径方向距離の最短距離近傍の画像
外縁の適当個数のドツト位置よりワークの弦部に
相当する部分の直線式を算出する手段３と、上記
重心より上記直線に下した垂線上で上記重心から
適当間隔ずらせてワークの円弧部を含む円の中心
を算出する手段４と、ワークの画像の面積より上
記円弧部を含む円の半径を算出する手段５と、上
記円の中心及び半径に基づく円弧部及び上記直線
式による弦とワークの画像外縁とを比較する手段
６とを備えている。
（作用）
ワークの画像の面積及び重心が手段１により算
出され、その重心からワークの画像外縁までの半
径方向距離が手段２により測定されてその半径方
向距離の最短距離近傍の画像外縁の適当個数のド
ツト位置よりワークの弦部に相当する部分の直線
式が手段３により算出される。上記重心より上記
直線に下した垂線上で上記重心から適当間隔ずら
せてワークの円弧部を含む円の半径が手段５によ
り算出されて手段６により上記円の中心及び半径
に基づく円弧部及び上記直線式による弦とワーク
の画像外縁とが比較される。
（実施例）
第２図は本発明の一実施例を示す。
この実施例はウエハーの２次元的外形（平面形
状）が円の一部を弦によつて切除した円弧部と弦
部とによつて形成される一部切除円形状であるか
ら、ウエハーの円弧部をウエハーの２次元的外形
の面積より逆算した真円と半径を比較し、ウエハ
ーの弦部を最小自乗法により算出した直線と比較
することでウエハーの欠落を検出するものであ
る。ビデオカメラ１１はウエハー１２をその上方
より撮像してビデオ信号を処理回路１３へ出力
し、処理回路１３ではビデオカメラ１１からのビ
デオ信号を２値化回路１４により２値化する。同
期分離タイミング発生回路１５はビデオカメラ１
１からのビデオ信号より同期信号を分離してこの
同期信号によりデータ取込用タイミング信号を発
生し、このタイミング信号により２値化回路１４
からのビデオ信号が画像メモリ１６に書込まれ
る。同期発生メモリ読み出し回路１７は同期信号
を発生し陰極線管（CRT）表示装置１８上に表
示でぎきるタイミングで画像メモリ１６からデー
タを読み出し、このデータを表示装置１８に送出
して表示させる。中央処理装置（CPU）１９及
びメモリ２０は内部バス２１で接続されていてマ
イクロコンピユータを構成し、メモリ２０は処理
プログラム用メモリ、ヒストグラム作成用メモリ
等で構成されている。
第３図は上記コンピユータの処理フロー及びそ
の説明図を示す。上記コンピユータはまず画像メ
モリ１６に２値化回路１４からのビデオ信号を書
き込ませて表示装置１８上にウエハー１２の２次
元の外形１２Ａを第３図ｂのように表示させ、画
像橋メモリ１６内のビデオ信号よりウエハー１２
の画素（ウエハー１２の２次元の外形内の画素）
をカウントしてウエハー１２の外形の面積Ｓとヒ
ストグラムを算出する。第３図ｂ２のようにこの
ヒストグラムはＸ，Ｙ座標の直交するＸ軸及びＹ
軸上について求め、これらのヒストグラムからウ
エハー１２の外形の重心の位置（GX，GY）を
計算する。次に、画像メモリ１６内のビデオ信号
を用いてウエハー１２の外形の外縁を求めて第３
図ｂ３，ｂ４のように重心位置GX，GYからウ
エハー１２の外形外縁までの距離を重心位置
GX，GYの周囲全体0゜〜360゜にわたつて測定し、
この距離の最小部を検出する。そして第３図ｂ５
のようにこの最小部付近の前後の適当な個数のド
ツト位置、つまりウエハー１２の外形の外縁上に
おける重心位置GX，GYに最も近い位置の近傍
にある一定個数のドツト（画素）位置Ｐ１〜Ｐ５
を求めてこれらから最小自乗法によりウエハー１
２の外形の弦部に相当する直線を近似する式ｙ＝
ax＋ｂを求める。ここに
である。次に第３図ｂ６のように重心位置GX，
GYから上記直線に下した垂線の延長方向に一定
の距離ｄだけ移動した位置SX，SYを重心位置
GX，GY、ｙ＝ax＋ｂ，ｄより算出し、第３図
ｂ７のようにこの位置SX，SYを中心とした半径
ｒの円と上記外形外縁の円弧部とを円周に沿つて
比較してそのズレ量を求める。ここにｄ＝ｒ×
0.015、
(Industrial Application Field) The present invention relates to an image processing apparatus for detecting notch damage in a detected object (hereinafter referred to as a workpiece) such as a wafer. (Prior Art) A method for detecting defects (missing) in the external shape of a wafer is carried out by visually determining defects in the external shape of the wafer based only on the area of the wafer. (Problems to be Solved by the Invention) In the above-mentioned conventional method, defects in the external shape of the wafer are visually determined based only on the area of the wafer, and therefore small defects in the wafer cannot be determined. For example, radius r
In the case of a 5-inch wafer with a tolerance of +0 mm - 0.5 mm, the area difference within the tolerance is πr 2 - πr' 2 = π {(127 mm/2) 2 - (127 mm/2 - 0.5 mm) 2 } = 2 cm 2 , Missing parts smaller than 2 cm 2 = 14 x 14 mm cannot be determined. This also applies when attempting to detect missing external shapes of workpieces other than wafers. (Means for Solving the Problems) As shown in FIG. 1, the present invention includes means 1 for calculating the area and center of gravity of an image of a workpiece, and means for measuring the radial distance from the center of gravity to the outer edge of the image of the workpiece. 2, a means 3 for calculating a linear equation of a portion corresponding to the chord part of the workpiece from an appropriate number of dot positions on the outer edge of the image near the shortest radial distance; Means 4 for calculating the center of a circle including the arc portion of the workpiece by shifting the center of gravity by an appropriate distance; Means 5 for calculating the radius of the circle including the arc portion from the area of the image of the workpiece; and the center and radius of the circle. It is provided with a means 6 for comparing the arc portion based on the equation and the chord based on the linear equation described above with the outer edge of the image of the workpiece. (Function) The area and center of gravity of the image of the workpiece are calculated by means 1, the radial distance from the center of gravity to the outer edge of the image of the workpiece is measured by means 2, and an appropriate number of outer edges of the image near the shortest radial distance are calculated. The linear equation of the part corresponding to the chord part of the workpiece is calculated by the means 3 from the dot position. Means 5 calculates the radius of a circle including the circular arc portion of the workpiece on a perpendicular line drawn from the center of gravity to the straight line, shifted by an appropriate interval from the center of gravity, and means 6 calculates the circular arc portion based on the center and radius of the circle and the straight line. The string according to the formula and the image outer edge of the workpiece are compared. (Example) FIG. 2 shows an example of the present invention. In this embodiment, the two-dimensional external shape (planar shape) of the wafer is a partially cut-off circular shape formed by a circular arc portion obtained by cutting a part of a circle by a string, and the string portion. The missing part of the wafer is detected by comparing the radius with a perfect circle calculated from the area of the two-dimensional outer shape of the wafer, and by comparing the chord part of the wafer with a straight line calculated by the method of least squares. The video camera 11 images the wafer 12 from above and outputs a video signal to the processing circuit 13 , where the video signal from the video camera 11 is binarized by the binarization circuit 14 . The synchronization separation timing generation circuit 15 is connected to the video camera 1.
A synchronizing signal is separated from the video signal from 1, and this synchronizing signal is used to generate a timing signal for data acquisition.
The video signal from is written to the image memory 16. A synchronization generation memory readout circuit 17 generates a synchronization signal, reads data from the image memory 16 at a timing that can be displayed on a cathode ray tube (CRT) display device 18, and sends this data to the display device 18 for display. A central processing unit (CPU) 19 and a memory 20 are connected by an internal bus 21 and constitute a microcomputer, and the memory 20 is composed of a processing program memory, a histogram creation memory, and the like. FIG. 3 shows a processing flow of the computer and an explanatory diagram thereof. The computer first writes the video signal from the binarization circuit 14 into the image memory 16 to display the two-dimensional outline 12A of the wafer 12 on the display device 18 as shown in FIG. From the video signal of wafer 12
(pixels within the two-dimensional outline of the wafer 12)
is counted to calculate the area S of the outer shape of the wafer 12 and the histogram. As shown in Figure 3 b2, this histogram shows the X and Y coordinates perpendicular to each other.
on the axis, and calculate the position (GX, GY) of the center of gravity of the outer shape of the wafer 12 from these histograms. Next, the outer edge of the wafer 12 is determined using the video signal in the image memory 16, and a third
As shown in Figures b3 and b4, the distance from the center of gravity GX, GY to the outer edge of the wafer 12 is the center of gravity
Measure the entire circumference of GX, GY from 0° to 360°,
Find the minimum of this distance. And Figure 3 b5
As shown in FIG.
Find wafer 1 from these using the least squares method.
Formula y = approximating the straight line corresponding to the chord part of the outer shape of 2
Find ax+b. Here It is. Next, as shown in Figure 3 b6, the center of gravity position GX,
The center of gravity is located at the positions SX and SY, which are moved by a certain distance d in the direction of extension of the perpendicular line drawn from GY to the above straight line.
Calculate from GX, GY, y = ax + b, d, and compare the circle of radius r centered at these positions SX, SY with the arc part of the outer edge of the above shape along the circumference as shown in Figure 3 b7. Find the amount of deviation. Here d=r×
0.015,
【式】であり、ウエハー１２
の面積Ｓと半径ｒの円の面積との差をDSとする
と、α＝０〜DSとなる。次に直線近似式ｙ＝ax
＋ｂによる直線と上記外形外縁の弦部とを比較し
てそのズレ量を求める。そしてこれらのズレ量
（ウエハー１２の円弧部、弦部とこれに対する上
記円、直線とのズレ量）が基準値以内か否かを判
定し、これによつてウエハー１２の外形外縁上の
隣合う２つのドツトが正規のドツト間隔の２倍以
内か否かを判定し、その結果を表示装置に表示さ
せる。
なお本発明はウエハーに限らず直線状に切除し
た一部切除円形部の物の切欠損傷を検出する場合
にも上記実施例と同様に適用することが可能であ
る。
（発明の効果）
以上のように本発明によれば、ワークの画像の
画像及び重心を算出してこの重心からワークの画
像外縁までの半径方向距離を測定し、この半径方
向距離の最短距離の近傍の画像外縁の適当個数の
ドツト位置よりワークの弦部に相当する直線の直
線式を算出して上記重心より上記直線に下した垂
線上で上記重心から適当間隔ずらせてワークの円
弧部を含む円の中心を算出し、ワークの画像の面
積より上記円弧部を含む円の半径を算出してこの
円の中心及び半径に基づく円弧及び上記直線式に
よる弦とワークの画像外縁とを比較するので、ワ
ークの小さな欠落を判別することが可能となる。
しかも、例えば４インチウエハーと５インチウエ
ハーの様に外形の比率がほぼ同じ物ならば同一の
装置で何も変更せずに検査でき、またワークがど
のような方向に置かれていても（ワークを任意の
方向にセツトしても）その切欠損傷を検査するこ
とができる。[Formula], and if DS is the difference between the area S of the wafer 12 and the area of a circle with radius r, α=0 to DS. Next, the linear approximation formula y=ax
The straight line defined by +b is compared with the chord part of the outer edge of the above-mentioned outline, and the amount of deviation thereof is determined. Then, it is determined whether these deviations (the deviations between the arcuate portions and chordal portions of the wafer 12 and the above-mentioned circles and straight lines) are within a reference value, and thereby the adjacent It is determined whether the distance between the two dots is within twice the regular dot interval, and the result is displayed on the display device. Note that the present invention can be applied not only to wafers, but also to the case of detecting notch damage in objects having partially cut circular parts cut out in a straight line, in the same manner as in the above embodiments. (Effects of the Invention) As described above, according to the present invention, the image and the center of gravity of the image of the workpiece are calculated, the radial distance from the center of gravity to the outer edge of the image of the workpiece is measured, and the shortest distance of this radial distance is calculated. Calculate the linear equation of a straight line corresponding to the chord part of the workpiece from the positions of an appropriate number of dots on the outer edge of the nearby image, and include the circular arc part of the workpiece by shifting an appropriate distance from the center of gravity on a perpendicular line drawn from the center of gravity to the straight line. Calculate the center of the circle, calculate the radius of the circle including the circular arc part from the area of the image of the workpiece, and compare the arc based on the center and radius of this circle, the chord according to the linear equation above, and the outer edge of the image of the workpiece. , it becomes possible to identify small defects in the workpiece.
Moreover, if the external proportions of wafers are almost the same, such as a 4-inch wafer and a 5-inch wafer, the same equipment can be used to inspect them without changing anything, and no matter what direction the workpiece is placed (workpiece ) can be set in any direction and inspected for notch damage.
第１図は本発明の構成を示すブロツク図、第２
図は本発明の一実施例を示すブロツク図、第３図
は同実施例の処理フローを示すフローチヤート及
び説明図である。
１……面積及び重心算出手段、２……半径方向
距離測定手段、３……直線式算出手段、４……中
心算出手段、５……半径算出手段、６……比較手
段。
Figure 1 is a block diagram showing the configuration of the present invention, Figure 2 is a block diagram showing the configuration of the present invention.
The figure is a block diagram showing one embodiment of the present invention, and FIG. 3 is a flowchart and explanatory diagram showing the processing flow of the same embodiment. 1... Area and center of gravity calculation means, 2... Radial distance measurement means, 3... Linear equation calculation means, 4... Center calculation means, 5... Radius calculation means, 6... Comparison means.
Claims (1)
とによつて形成される一部切除円形状の被検出体
の切欠損傷を検出する画像処理装置であつて、上
記被検出体の画像の面積及び重心を算出する手段
と、上記重心から上記被検出体の画像外縁までの
半径方向距離を測定する手段と、上記半径方向距
離の最短距離の近傍の画像外縁の適当個数のドツ
ト位置より上記弦部に相当する部分の直線式を算
出する手段と、上記重心より上記直線に下した垂
線上で上記重心から適当間隔ずらせて上記円弧部
を含む円の中心を算出する手段と、上記被検出体
の画像の面積より上記円弧部を含む円の半径を算
出する手段と、上記手段で算出して被検出体の画
像の円弧部を含む円の中心から上記手段で算出し
た被検出体の画像の円弧部を含む円の半径に基づ
く円弧及び上記直線式による弦と上記被検出体の
画像外縁とを比較する手段とを備えた画像処理装
置。1. An image processing device for detecting notch damage in a detected object having a partially cut-out circular shape formed by a circular arc portion obtained by cutting out a part of a circle by a string, and a string portion, the above-mentioned detected object means for calculating the area and center of gravity of the image, means for measuring the radial distance from the center of gravity to the outer edge of the image of the object to be detected, and an appropriate number of dots on the outer edge of the image near the shortest radial distance. means for calculating a linear equation of the part corresponding to the chord part from the position; means for calculating the center of a circle including the circular arc part by shifting an appropriate distance from the center of gravity on a perpendicular line drawn from the center of gravity to the straight line; means for calculating the radius of a circle including the arc portion from the area of the image of the object to be detected, and a detection object calculated by the means from the center of the circle including the arc portion of the image of the object to be detected; An image processing device comprising means for comparing an outer edge of the image of the object to be detected with an arc based on the radius of a circle including the arc portion of the image of the body and a chord based on the linear equation.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP26090885A JPS62120039A (en) | 1985-11-20 | 1985-11-20 | Image processor |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP26090885A JPS62120039A (en) | 1985-11-20 | 1985-11-20 | Image processor |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS62120039A JPS62120039A (en) | 1987-06-01 |
| JPH0528499B2 true JPH0528499B2 (en) | 1993-04-26 |
Family
ID=17354430
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP26090885A Granted JPS62120039A (en) | 1985-11-20 | 1985-11-20 | Image processor |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS62120039A (en) |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP3023566B2 (en) * | 1990-08-30 | 2000-03-21 | 株式会社東京精密 | Dicing equipment |
| JP4693817B2 (en) * | 2007-07-02 | 2011-06-01 | 日東電工株式会社 | Adhesive tape affixing method to semiconductor wafer and protective tape peeling method |
-
1985
- 1985-11-20 JP JP26090885A patent/JPS62120039A/en active Granted
Also Published As
| Publication number | Publication date |
|---|---|
| JPS62120039A (en) | 1987-06-01 |
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