JPH01121709A - Pattern inspecting device - Google Patents

Abstract

PURPOSE:To omit a large amount of hardware for accurate positioning performing preprocessing for the enlargement and reduction of the pattern of an article to be inspected and then detecting the number of feature points, and comparing it with the number of feature points of a reference pattern and deciding whether or not the object article is normal. CONSTITUTION:A binarization part 2 binarizes a video signal (f) into a binarization signal (g), An enlargement processing part 3 outputs the enlarged pattern signal (h) of the signal (f). A branch point quantity detection part 4 finds the number of branch points of the signal (h). A switch part 5 supplies the branch point quantity signal (i) to a storage part 6 as a normal article pattern and to a comparison part 12 as a pattern to be inspected. A comparison part 7 compares a stored signal (j) with an inspected article signal (r) and outputs a comparison signal (k) when they coincide with each other. A reduction processing part 8, on the other hand, outputs the reduced pattern signal of the signal (g). An end point quantity detecting circuit 9 finds the number of end points of a signal (l). An end point quantity signal (m) is distributed by a switch part 10 as mentioned above. The comparison part 12 outputs the comparison signal (u) between a storage signal (n) and an inspected article signal (t). A logic part 13 ORs the signals (k) and (u) and outputs an acceptance signal (p).

Description

【発明の詳細な説明】 〔産業上の利用分野〕 本発明はパターン検査装置、特に、辞書を有しプリント
基板のパターンの欠陥を検査するパターン検査装置に関
する。DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a pattern inspection device, and more particularly to a pattern inspection device that has a dictionary and inspects defects in patterns on printed circuit boards.

〔従来の技術〕[Conventional technology]

従来の技術としては、例えば、外観検査の自動化、第５
６頁、電気学会（昭和５９年）に示されているように、
パターン比較装置がある。Conventional technologies include, for example, automation of visual inspection,
As shown in page 6, Institute of Electrical Engineers of Japan (1988),
There is a pattern comparison device.

第７図は従来のパターン検査装置の一例を示す原理説明
図である。FIG. 7 is a diagram explaining the principle of an example of a conventional pattern inspection device.

従来のパターン検査装置は、被検査品のパターン１４と
基準となる良品のパターン１５との精密な位置合わせを
行った後、両者を比較し、一致しない部分を欠陥として
検出することにより、良品、不良品の判定をしていた。Conventional pattern inspection equipment performs precise alignment between the pattern 14 of the inspected product and the standard pattern 15 of a non-defective product, then compares the two and detects non-conforming portions as defects. They were determining whether the product was defective.

〔発明が解決しようとする問題点〕[Problem that the invention seeks to solve]

上述した従来のパターン検査装置は、比較検査を行なう
ために、精密な位置合わせを行なるなくてはならず、こ
のため位置合わせに必要な検出系や駆動系などの膨大な
ハードウェアが必要であり、また位置合わせ精度以下の
微細な欠陥が検出できないという欠点があった。The conventional pattern inspection equipment described above requires precise alignment in order to perform comparative inspection, which requires a huge amount of hardware such as detection systems and drive systems necessary for alignment. This method also has the disadvantage that it cannot detect minute defects that are less than the alignment accuracy.

〔問題点を解決するための手段〕 本発明のパターン検査装置は、撮影画像を光電変換しビ
デオ信号を出力する光な変換部と、前記ビ゛デオ信号を
二値化し二値化信号を出力する二値化部と、前記二値化
信号を画素単位に拡大処理を行い拡大パターン信号を出
力する拡大処理部と、前記拡大パターン信号にもとづい
て分岐点の数を検出して分岐点数信号を出力する分岐点
数検出部と、前記撮影画像が基準となる良品パターンの
ときには前記分岐点数信号を第１の記憶部に第１の基準
信号として供給し被検査品パターンのときは第１の比較
部に第１の被検査品信号として供給する第１の切り替え
部と、前記第１の基準信号を記憶し第１の記憶信号を出
力する第１の記憶部と、前記第１の被検査品信号と前記
第１の記憶信号とを比較して両者が一致した場合に第１
の比較信号を出力する第１の比較部と、前記二値化信号
を画素単位に縮小処理を行い縮小パターン信号を出力す
る縮小処理部と、前記縮小パターン信号にもとづいて端
点数を検出し端点数信号を出力する端点数検出部と、前
記撮影画像が基準となる良品パターンのときには前記端
点数信号を第２の記憶部に第２の基準信号として供給し
被検査品パターンのときは第２の比較部に第２の被検査
品信号として供給する、第２の切り替え部と、前記第２
の基準信号を記憶し第２の記憶信号を出力する第２の記
憶部と、前記第２の被検査品信号と前記第２の記憶信号
とを比較して両者が一致した場合に第２の比較信号を出
力する第２の比較部と、前記第１の比較信号と前記第２
の比較信号とが同時に存在した場合にのみ合格信号を出
力する論理部とを含んで構成される。[Means for Solving the Problems] The pattern inspection device of the present invention includes an optical conversion section that photoelectrically converts a photographed image and outputs a video signal, and a converter that binarizes the video signal and outputs a binarized signal. an enlargement processing section for enlarging the binarized signal pixel by pixel and outputting an enlarged pattern signal; and an enlargement processing section for detecting the number of branch points based on the enlarged pattern signal and outputting a branch point number signal. a branch point number detecting section that outputs the branch point number signal, and a first comparison section that supplies the branch point number signal to a first storage section as a first reference signal when the photographed image is a standard non-defective pattern, and when it is an inspected product pattern; a first switching unit that supplies the signal as a first product-to-be-inspected signal; a first storage unit that stores the first reference signal and outputs a first storage signal; and a first storage unit that stores the first reference signal and outputs a first storage signal; and the first memory signal, and if they match, the first memory signal is
a first comparison section that outputs a comparison signal of , a reduction processing section that performs reduction processing on the binarized signal pixel by pixel and outputs a reduced pattern signal, and a reduction processing section that detects the number of end points based on the reduced pattern signal and a corner point number detection unit that outputs a point number signal, and a second storage unit that supplies the corner point number signal as a second reference signal when the photographed image is a standard non-defective pattern, and a second storage unit when the captured image is a pattern of a product to be inspected; a second switching section that supplies the comparison section with a second product-to-be-inspected signal;
a second storage section that stores a reference signal of the first one and outputs a second stored signal; and a second storage section that stores a reference signal of the second inspected product signal and outputs a second stored signal; a second comparison section that outputs a comparison signal; and a second comparison section that outputs a comparison signal;
and a logic section that outputs a pass signal only when the comparison signal and the comparison signal of .

〔実施例〕〔Example〕

次に、本発明の実施例について図面を参照して説明する
。Next, embodiments of the present invention will be described with reference to the drawings.

第１図は本発明の一実施例を示すブロック図である。FIG. 1 is a block diagram showing one embodiment of the present invention.

第１図に示すパターン検査装置は、拡大処理部３と分岐
点数検出部４と比較部７と縮小処理部８と端点数検出部
９と比較部１２と論理部１３とを含んで構成される。The pattern inspection device shown in FIG. 1 includes an enlargement processing section 3, a branch point number detection section 4, a comparison section 7, a reduction processing section 8, an end point number detection section 9, a comparison section 12, and a logic section 13. .

光電変換部１は、被撮影画像をビデオ信号ｆに変換し、
二値化部２でこれを二値化し二値化信号ｇを作成する。The photoelectric conversion unit 1 converts the photographed image into a video signal f,
A binarization unit 2 binarizes this to create a binarized signal g.

拡大処理部３は、二値化されたパターンを拡大し、拡大
パターン信号りを出力するもので、３×３のマスクを用
い着目している画素の周辺の画素のうち一つでも黒画素
があるときは、着目している画素を黒に変換する。The enlargement processing unit 3 enlarges the binarized pattern and outputs an enlarged pattern signal, and uses a 3×3 mask to detect if even one black pixel is present in the vicinity of the pixel of interest. If so, convert the pixel of interest to black.

拡大処理部３では、パターンの最小間隔をあらかじめ調
査しておき、良品のパターンを拡大してもパターン同志
が接触しないように拡大処理の回数を決定しておく。In the enlargement processing section 3, the minimum interval between patterns is investigated in advance, and the number of times of enlargement processing is determined so that even if a good pattern is enlarged, the patterns do not come into contact with each other.

第２図（ａ）の良品パターンを拡大処理したものが第２
図（ｂ）に示され、第３図（ａ）の欠陥を含むパターン
を拡大処理したものが第３図（ｂ）であり突起部分が隣
りのパターンと接触している。The second image is an enlarged version of the non-defective pattern in Figure 2(a).
FIG. 3(b) is an enlarged version of the defective pattern shown in FIG. 3(a), and the protruding portion is in contact with the adjacent pattern.

分岐点数検出部４では、拡大パターン信号りを細線化し
て、分岐点の数を求め、る。The branch point number detection unit 4 thins the expanded pattern signal to find the number of branch points.

第２図（ｃ）および第３図（ｃ）は、それぞれ第２図（
ｂ）および第３図（ｂ）に示したパターンを細線化した
結果を示し、分岐点の数を３×３のマスクを用いて検出
すると、良品パターンではＢ１−Ｂ２の２分岐点、欠陥
を含むパターンでは、Ｂ１〜Ｂ６の６分岐点が検出され
る。Fig. 2(c) and Fig. 3(c) respectively correspond to Fig. 2(c) and Fig. 3(c).
The results of thinning the patterns shown in b) and Fig. 3(b) are shown, and when the number of branch points is detected using a 3 x 3 mask, there are two branch points B1-B2 and defects in the non-defective pattern. In the pattern including this, six branch points B1 to B6 are detected.

分岐点とは、画像を画素単位に考えたときの連結数が３
となる画素のことをいい、第６図（ｂ）は分岐点の一例
である。なお、第６図（ａ）は端点、第６図（ｃ）は孤
立点、第６図（ｄ）は交点の一例を示す。ここで、連結
数４の交点は分岐点の数が２とカウントする。A branch point is a point where the number of connections is 3 when considering the image pixel by pixel.
6(b) is an example of a branch point. Note that FIG. 6(a) shows an example of an end point, FIG. 6(c) shows an isolated point, and FIG. 6(d) shows an example of an intersection point. Here, an intersection with a connection number of 4 is counted as a branch point of 2.

分岐点数信号ｉは、切り替え部５によって基準となる良
品パターンの場合は記憶部６へ、被検査品のパターンの
場合は比較部７へ供給される。The branch point number signal i is supplied by the switching unit 5 to the storage unit 6 in the case of a standard non-defective pattern, and to the comparison unit 7 in the case of the pattern of the inspected product.

比較部７は記憶信号ｊと被検査品信号ｒとを比較し両者
が一致すれば、被検査品にショートや突起がないと判定
し、比較信号ｋを出力する。The comparator 7 compares the stored signal j and the inspected product signal r, and if they match, it determines that there is no short circuit or protrusion in the inspected product, and outputs a comparison signal k.

縮小処理部８では、二値化信号ｇであられされるパター
ンを縮小し、縮小パターン信号ｌを出力する。縮小処理
とは、３×３のマスクを用い、着目している画素の周辺
の画素のうち、１つでも白画素があるときは着目してい
る画素を白に変換する処理のことをいう。The reduction processing unit 8 reduces the pattern rendered by the binary signal g and outputs a reduced pattern signal l. The reduction process is a process in which a 3×3 mask is used to convert the pixel of interest to white if there is even one white pixel among the surrounding pixels of the pixel of interest.

・　縮小処理部８では、あらかじめパターンの最小線幅
を調査しておき、良品パターンを縮小してもパターンの
つながりが途中で途切れないように縮小処理回数を決定
しておく。- In the reduction processing unit 8, the minimum line width of the pattern is investigated in advance, and the number of reduction processing times is determined so that even if a good pattern is reduced, the connection between the patterns will not be interrupted.

第４図（ａ）の良品パターンを縮小すると第４図（ｂ）
のようになり、第５図（ａ）の欠陥を含むパターンを縮
小した結果が第５図（ｂ）であり、縮小処理したなめ欠
損部分が広がり、パターンが途切れた様子を示している
。When the non-defective pattern in Figure 4(a) is reduced, Figure 4(b) is obtained.
FIG. 5(b) shows the result of reducing the defective pattern shown in FIG. 5(a), and shows that the reduced defective portion has expanded and the pattern has been interrupted.

端点数検出部９では、縮小パターン信号ｌを細線化し端
点数を求め端点数信号ｍを出力する。The endpoint number detecting section 9 thins the reduced pattern signal l, determines the number of endpoints, and outputs an endpoint number signal m.

端点とは、画像を画素単位で考えたときの連結数が１と
なる画素のことをさし、第６図（ａ）は端点の一例であ
る。なお、第６図＜ｅ）に示す孤立点は・端点数が２と
カウントする。An end point refers to a pixel for which the number of connections is 1 when considering an image pixel by pixel, and FIG. 6(a) is an example of an end point. Note that the isolated point shown in FIG. 6<e) is counted as 2 end points.

第４図（ｃ）および第５図（ｅ）は、それぞれ第４図（
ｂ）および第５図（ｂ）に示したパターンを縮小した結
果を示し、良品パターンではＴ１〜Ｔ２の２端点、欠陥
を含むパターンでは、Ｔ１〜Ｔ６の６端点が検出される
。Figure 4(c) and Figure 5(e) are respectively shown in Figure 4(c) and Figure 5(e).
b) and the result of reducing the pattern shown in FIG. 5(b), in which two end points T1 to T2 are detected in the non-defective pattern, and six end points T1 to T6 are detected in the defective pattern.

端点数信号ｍは、切り替え部１０によって基準となる良
品パターンの場合は記憶部１１へ、被検査品のパターン
の場合は比較部１２へ供給される。The end point number signal m is supplied by the switching unit 10 to the storage unit 11 in the case of a standard non-defective pattern, and to the comparison unit 12 in the case of the pattern of the inspected product.

比較部１２は記憶信号ｎと被検査品信号ｔとを比較し両
者が一致すれば、被検査品に断線や欠損がないと判定し
、比較信号Ｕを出力する。The comparator 12 compares the stored signal n and the inspected product signal t, and if they match, it determines that there is no disconnection or defect in the inspected product, and outputs a comparison signal U.

論理部１３は比較信号にと比較信号Ｕとの論理積を演算
し合格信号ｐを出力する。すなわち、分岐点数と端点数
の双方が基準となる良品パターンに一致した場合にのみ
合格信号が発生する。The logic unit 13 calculates the AND of the comparison signal and the comparison signal U, and outputs a pass signal p. That is, a pass signal is generated only when both the number of branch points and the number of end points match the standard non-defective pattern.

なお、本実施例では二値化な、パターンを黒、背景を白
として説明したが、これを逆にパターンを白、背景を黒
とするように二値化を行ない、白画素を黒画素に、黒画
素を白画素に置代えても上述の原理が成立する。In addition, in this example, the explanation was given for binarization in which the pattern is black and the background is white, but this is reversed and the binarization is performed so that the pattern is white and the background is black, and white pixels are converted to black pixels. , the above principle holds true even if black pixels are replaced with white pixels.

〔発明の効果〕〔Effect of the invention〕

本発明のパターン検査装置は、被検査品のパターンを拡
大、縮小の前処理をした後、細線化し端点、分岐点とい
う特徴点の数を検出し、基準パターンの特徴点数と比較
して良品、不良品の判定を行なうため、精密位置合せの
ための膨大なハードウェアを省略でき、また、微細なシ
ョート、断線、欠損、突起などが検出できるという効果
がある。The pattern inspection device of the present invention preprocesses the pattern of the inspected product by enlarging or reducing it, then thins it, detects the number of feature points such as end points and branch points, and compares it with the number of feature points of the reference pattern to determine whether it is a good product or not. Since defective products are determined, a large amount of hardware for precise alignment can be omitted, and minute shorts, wire breaks, defects, protrusions, etc. can be detected.

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

］・・・光電変換部、２・・・二値化部、３・・・拡大
処理部、４・・・分岐点数信号部、５．１０・・・切り
替え部−５６，１１・・・記憶部、７．１２・・・比較
部、８・・・縮小処理部、９・・・端点数検出部、１３
・・・論理部、ｆ・・・ビデオ信号、ｇ・・・二値化信
号、ｈ・・・拡大パターン信号、ｉ・・・分岐点数信号
、ｊ、ｎ・・・記憶信号、ｋ、ｕ・・・比較信号、１・
・・縮小パターン信号、ｍ・・・端点数信号、ｐ・・・
合格信号、ｑ、ｓ・・・基準信号、ｒ、ｔ・・・被検査
品信号。 代理人　弁理士　　内　原　　音]... Photoelectric conversion unit, 2... Binarization unit, 3... Enlargement processing unit, 4... Branch point number signal unit, 5.10... Switching unit -56, 11... Storage Part, 7.12... Comparison part, 8... Reduction processing part, 9... Endpoint number detection part, 13
...Logic section, f...Video signal, g...Binarized signal, h...Enlarged pattern signal, i...Band point number signal, j, n...Storage signal, k, u ... Comparison signal, 1.
...Reduced pattern signal, m...Endpoint number signal, p...
Acceptance signal, q, s... reference signal, r, t... signal of the product to be inspected. Agent Patent Attorney Oto Uchihara

Claims (1)

【特許請求の範囲】[Claims] 　撮影画像を光電変換しビデオ信号を出力する光電変換
部と、前記ビデオ信号を二値化し二値化信号を出力する
二値化部と、前記二値化信号を画素単位に拡大処理を行
い拡大パターン信号を出力する拡大処理部と、前記拡大
パターン信号にもとづいて分岐点の数を検出して分岐点
数信号を出力する分岐点数検出部と、前記撮影画像が基
準となる良品パターンのときには前記分岐点数信号を第
１の記憶部に第１の基準信号として供給し被検査品パタ
ーンのときは第１の比較部に第１の被検査品信号として
供給する第１の切り替え部と、前記第１の基準信号を記
憶し第１の記憶信号を出力する第１の記憶部と、前記第
１の被検査品信号と前記第１の記憶信号とを比較して両
者が一致した場合に第１の比較信号を出力する第１の比
較部と、前記二値化信号を画素単位に縮小処理を行い縮
小パターン信号を出力する縮小処理部と、前記縮小パタ
ーン信号にもとづいて端点数を検出し端点数信号を出力
する端点数検出部と、前記撮影画像が基準となる良品パ
ターンのときには前記端点数信号を第２の記憶部に第２
の基準信号として供給し被検査品パターンのときは第２
の比較部に第２の被検査品信号として供給する第２の切
り替え部と、前記第２の基準信号を記憶し第２の記憶信
号を出力する第２の記憶部と、前記第２の被検査品信号
と前記第２の記憶信号とを比較して両者が一致した場合
に第２の比較信号を出力する第２の比較部と、前記第１
の比較信号と前記第２の比較信号とが同時に存在した場
合にのみ合格信号を出力する論理部とを含むことを特徴
とするパターン検査装置。A photoelectric conversion section that photoelectrically converts a photographed image and outputs a video signal, a binarization section that binarizes the video signal and outputs a binarized signal, and an enlargement process that enlarges the binarized signal pixel by pixel. an enlargement processing section that outputs a pattern signal; a branch point number detection section that detects the number of branch points based on the enlarged pattern signal and outputs a branch point number signal; and a branch point number detection section that detects the number of branch points based on the expanded pattern signal and outputs a branch point number signal; a first switching section that supplies the point signal to a first storage section as a first reference signal and supplies the point signal as a first inspection object signal to a first comparison section when it is an inspection object pattern; a first storage unit that stores a reference signal of the first item and outputs a first storage signal; and a first storage unit that stores a reference signal of the first item to be inspected and outputs a first storage signal; a first comparison section that outputs a comparison signal; a reduction processing section that performs reduction processing on the binarized signal pixel by pixel and outputs a reduced pattern signal; and a reduction processing section that detects the number of end points based on the reduced pattern signal and detects the number of end points. a corner point number detection section that outputs a signal; and a second storage section that stores the corner point number signal in a second storage section when the captured image is a standard non-defective pattern;
It is supplied as the reference signal of the
a second switching unit that supplies the second inspection target signal to the comparison unit of the second inspection unit; a second storage unit that stores the second reference signal and outputs a second storage signal; a second comparison section that compares the inspection product signal and the second storage signal and outputs a second comparison signal when the two match;
and a logic section that outputs a pass signal only when the comparison signal and the second comparison signal are present at the same time.