WO2001075801A1

WO2001075801A1 - Solder hole inspecting device

Info

Publication number: WO2001075801A1
Application number: PCT/JP2000/002040
Authority: WO
Inventors: Takayuki Haga
Original assignee: Kokusai Gijutsu Kaihatsu Kabushiki Kaisha
Priority date: 2000-03-30
Filing date: 2000-03-30
Publication date: 2001-10-11

Abstract

A solder hole is inspected for all inspection items. Based on image data collected by imaging a board on which a solder hole is made by a CCD, the shape parameter and the secondary parameter are compared with prescribed values to deal with various defects.

Description

TECHNICAL FIELD The present invention relates to a solder hole pass / fail determination device, and more particularly to a solder hole pass / fail determination device, and more particularly, to inspect a solder hole defect that is to be an electrode arranged in an array on a substrate. The present invention relates to a device for determining the quality of solder holes. In recent years, there has been an increasing demand for miniaturization of semiconductor devices. Therefore, semiconductor devices of a chip size package (hereinafter referred to as a CSP) in which the external dimensions of the semiconductor device have been reduced to almost the external dimensions of the semiconductor have been developed. Proposed.

As a semiconductor device of this CSP, for example, a semiconductor element is fixed on a substrate having an external dimension slightly larger than the external dimension of the semiconductor element with an adhesive or the like, and an electrode formed on a peripheral part of the semiconductor element and a peripheral part of the substrate are used. The electrodes formed on the printed circuit board are electrically connected to each other with gold wires or the like, electrodes are formed in an array on the bottom surface of the substrate, and the electrodes are formed on the printed circuit board in the same manner as the electrodes, and A spherically formed solder ball is inserted between the two and heated to melt the solder and electrically connect the two.

Further, there has been proposed a method in which electrodes are formed in an array on the back side of a semiconductor element, and the electrodes are directly connected to an array of electrodes formed on a printed circuit board using solder balls.

Hereinafter, electrodes for connecting with solder balls on these substrates will be referred to as solder holes.

In this connection method between the printed circuit board and the semiconductor device, since the connection point with solder is below the semiconductor device, it is not possible to directly observe this soldering situation, and X-ray photography And other devices are required.

Therefore, in this connection method, it is necessary to guarantee 100% that there is no defect in the finish of each member and that it is a non-defective product, and to perform no inspection after the solder connection. The inspection target of the solder hole includes defects caused by various factors such as resist bleeding around the solder hole, defective plating, defective etching, adhesion of dust, etc. It is necessary to judge. DISCLOSURE OF THE INVENTION The present invention has been made in view of the above-mentioned facts, and has as its object to provide an apparatus for determining the quality of a solder hole that acts on various defects in the solder hole.

In order to achieve the above object, the present invention provides: a photographing means for photographing a substrate having a solder hole formed thereon, and the solder hole based on image data obtained by photographing the substrate by the photographing means. Calculating means for calculating a physical quantity representing the characteristic of the solder hole; comparing the physical quantity representing the characteristic of the solder hole calculated by the calculating means with a reference value serving as a reference for judging the quality of the solder hole; Determining means for determining the quality of the hole.

That is, the photographing means photographs the substrate on which the plated solder holes are formed. The calculating means calculates a physical quantity representing a feature of the solder hole based on image data obtained by photographing the substrate by the photographing means. That is, the calculation means calculates a physical quantity representing a feature of the solder hole by labeling based on the image data. Here, labeling refers to treating similar continuous pixels in the image data as a block, and as a result of the labeling, the characteristics (position, height, width, total number of pixels, aspect ratio, etc.) of the block are obtained. In the case of this device, labeling is performed on a plurality of shot solder holes, and when one of the solder holes is labeled, one is provided for each solder hole. A labeling result is obtained.

The determining means compares the physical quantity representing the characteristics of the solder hole calculated by the calculating means with a reference value serving as a reference for determining the quality of the solder hole. The quality of the through hole is determined. Note that this reference value may also be obtained by the above-described labeling in image data obtained by previously photographing a regular board.

Thus, based on the image data obtained by photographing the substrate on which the solder holes are formed, physical quantities representing the features of the solder holes are calculated, and the physical quantities representing the features of the solder holes, a reference value, and the like. Is compared to determine the quality of the solder hole, so that the quality of the solder hole can be accurately determined.

The calculating means may calculate a physical quantity relating to the brightness of the solder hole or a physical quantity relating to the shape of the solder hole as the physical quantity representing the feature of the solder hole.

Here, the physical quantity relating to the brightness of the solder hole may be a histogram or an average of the brightness of the solder hole on at least one assumed line assumed on the solder hole.

The physical quantities related to the shape of the solder hole include a first width of the solder hole in a predetermined direction, a second width (so-called height) in a direction perpendicular to the predetermined direction, an area, the first width and the second width. And the occupancy (the ratio of the area to the ratio of the first width and the second width to the ratio). On the other hand, when the calculating means calculates the physical quantity relating to the brightness of the solder hole as the physical quantity representing the characteristics of the solder hole, the determining means obtains a reference value based on the physical quantity relating to the brightness of the solder hole, The quality of the solder hole may be determined by comparing the physical quantity representing the characteristic of (1) with the obtained reference value to determine the quality of the solder hole.

Here, there are the following reference values obtained based on the physical quantity relating to the brightness of the solder hole.

That is, there is a predetermined percentage (for example, 80%) of the average brightness of the solder holes on at least one assumed line assumed on the solder holes. The average brightness of the solder hole on at least one assumed line assumed on the solder hole includes the average brightness of the entire area of the solder hole. Also, when a plurality of solder holes are formed on the substrate, the average of the average brightness of the solder holes on at least one assumed line of each of the plurality of solder holes of at least one substrate. It is a predetermined percentage (for example, 80%). BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 is a diagram showing a pass / fail determination device according to the present embodiment.

FIG. 2 is a block diagram of the pass / fail determination device.

FIGS. 3A to 3C are views showing the appearance of an image obtained by photographing and the structure of a solder hole.

4A to 4C are diagrams illustrating the brightness of a solder hole.

FIGS. 5A and 5B are diagrams showing various types of defects in the solder holes.

FIG. 6 is a diagram illustrating a method for detecting a defective brightness portion according to a modification. 7A and 7B are diagrams illustrating a method for detecting a defective brightness portion according to another modification. BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

As shown in FIG. 1, a defect determination device as a solder hole pass / fail determination device according to the present embodiment includes a light source 10 for illuminating the inspection target 200 and a camera (for example, a camera for photographing the illuminated inspection target 200). A two-dimensional CCD sensor or the like) 12, and a determination device 14 that determines pass / fail from an image signal of the inspection target 200 captured by the camera 12.

Here, in the present embodiment, the belt 13 is moved by the motor 11 driven in accordance with the control of the determination device 14 so as to convey the inspection object arranged on the belt 13.

The inspected object for which the judgment result is obtained is marked by a marking device (not shown) on a defective portion or sent to a device for sorting defective and non-defective products.

FIG. 2 shows a block diagram of a control system for image processing of the inspection device 14. As shown in FIG. 2, the judging device 14 is an AMP 16 that amplifies an analog signal of the inspection object 200 photographed by the camera 12 and an AZD conversion that converts the analog signal amplified by the AMP 16 into a digital signal. And a shading circuit 20 for performing shading processing based on the digital image signal converted by the A / D converter 18. A lookup table and a data processing circuit 26 (not shown) are connected to the shading circuit 20.

FIG. 3 shows a state of the solder hole of the object 200 to be inspected. FIG. 3A shows the state of the entire substrate, and FIG. 3B shows the state of an area corresponding to one semiconductor device therein, in which solder holes are formed in an array. FIG. 3C is a diagram showing a cross section of one of the solder holes. In addition, the solder hole H is provided in the resist 30 on the base material 40. Figure 4 shows the brightness of the image of the solder hole.Figure 4A shows an example of an image of a single solder hole, and the brightness of the image of the assumed line AB on the solder hole. Figure 4B shows the result. The solder hole is rough on a metal surface, and the image obtained by illuminating the solder hole does not show a constant value as shown in FIG.

Fig. 4C shows a histogram of the brightness of the image of the solder hole.If the solder hole is not completely removed, the brightness of the part of the metal surface of the pattern before this plating will change. . For example, a histogram indicated by NG in FIG. 4C is obtained.

Also, this difference can be determined by judging that the brightness is within the average value V arv force reference value.

Fig. 5 shows various types of defects in the solder hole, and Fig. 5A shows an example of an image of a solder hole in which partial defect of solder hole, bleeding of resist, adhesion of foreign matter, etc. occurred. .

Calculate the width X, height Y, and area S of one solder hole from the image taken as shown in Fig. 5B, and calculate the aspect ratio R = YX and occupancy Q = SZXY as its secondary parameters. Here, each value X, Y, S, R, and Q is compared with reference values Xo, Yo, So, Ro, and Qo to judge whether the values are within predetermined values to determine pass / fail. . This makes it possible to detect various defects as shown in FIG. 5A. Fig. 6 shows the average value of the brightness Varv in one solder hole, and the ratio of the area of the brightness less than this as a reference value with α * 100% of the Varv as the reference value. This makes it possible to detect a defect that is thin and dark.

Figure 7 7 shows the solder holes arranged in an array of one semiconductor device. The average value Vavr of the brightness of each solder hole is all added, and the sum is divided by the total number of solder holes n. Is determined, and a solder hole with a brightness of Varv less than / 9 * 100% of the total average value Varv—all is determined to be defective. In such a configuration, only the solder hole connected to the solder hole is defective due to disconnection of the pattern or the like, and the solder hole in this unique state is detected.

FIG. 7B shows a substrate on which a plurality of semiconductor devices are arranged (the same as in FIG. 3A). The total average value Varv—all of the solder hole brightness of the one semiconductor device Varv_i c—bd Determine within the board. This average value Varvjc—A solder hole with Varv of brightness less than y * 100% of bd is judged as defective. By doing so, it becomes possible to accurately detect defects even with respect to fluctuations in lighting and color fluctuations in the entire pattern that varies from lot to lot.

The average value Varvjc-bd is used to label the image data obtained by binarizing the image data at δ * 100% of this average value Varv_icjDd, and the width X, height Υ, and area of each solder hole are obtained. Calculate S, and calculate the aspect ratio R = ΥΖΧ and occupancy Q = SZXY as its secondary parameters, and calculate the values X, Y, S, R, and Q as reference values Xo, Yo, So, and Ro. By comparing with Qo to judge whether it is within the default value or not, it is possible to detect failures with high accuracy even with respect to fluctuations in lighting and color variations of the entire plating that vary from lot to lot. , And high-speed processing is possible because of the labeling of binary data.

Claims

The scope of the claims

1. A photographing means for photographing a substrate having a solder hole formed thereon, and a physical quantity representing the characteristic of the solder hole is calculated based on image data obtained by photographing the substrate by the photographing means. Calculating means;

Determining means for determining the quality of the solder hole by comparing a physical quantity representing the feature of the solder hole calculated by the calculation means with a reference value for determining the quality of the solder hole,

Solder hole quality judgment device equipped with

2. The good or bad solder hole according to claim 1, wherein the calculating means calculates a physical quantity related to the brightness of the solder hole or a physical quantity related to the shape of the solder hole as the physical quantity representing the feature of the solder hole. Judgment device.

3. The calculating means calculates a physical quantity relating to the brightness of the solder hole as a physical quantity representing the feature of the solder hole,

The determining means obtains the reference value based on a physical quantity related to the brightness of the solder hole, and compares the physical quantity representing the characteristic of the solder hole with the obtained reference value to determine the quality of the solder hole.

3. The solder hole quality judgment device according to claim 2, wherein: