JP3056155B2 - Foreign matter inspection between leads - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for inspecting foreign matter between leads for inspecting whether foreign matter such as lead burrs or tie bars exist between IC leads.

[0002]

2. Description of the Related Art Conventionally, as a method of inspecting whether there is a foreign matter such as a lead burr or a tie bar between IC leads, a method of providing a scan line and a method of masking the leads are known.

In a method of providing a scan line, for example, as shown in FIGS. 10 and 11, a scan line 61 parallel to the side surface of a lead 60 is provided between leads 60, and the density of each pixel on the scan line 61 is determined. If a pixel (defective pixel) equal to or larger than the threshold value is detected on the scan line 61, it is determined that a foreign substance exists between the leads. Since this method performs inspection only on the scan line 61, the inspection time is short, and is suitable for easily inspecting for foreign matter between leads.

In the method of masking a lead, for example, as shown in FIG. 12, an average density is obtained for an image 90 in a range including a lead, and a threshold is obtained from the average density.
The lead 91 is distinguished from the background 92 by this threshold value, and when there are a predetermined number or more of pixels exceeding the threshold value in the image 90 masking the lead 91, it is determined that a foreign substance exists between the leads. . This method is suitable for inspecting the foreign matter between leads in detail.

FIG. 8 shows an outline of an inspection apparatus used for performing an inter-lead foreign matter inspection. Reference numeral 11 denotes an image input device, which can be composed of, for example, a CCD camera, a video camera, a scanner, and the like. 12 is
Illumination device, for example, fluorescent lamp illumination, ring illumination, L
It can be composed of ED lighting or the like. Reference numeral 13 denotes an IC serving as an inspection object (sample). Reference numeral 14 denotes an image processing device that performs a predetermined process on an IC image captured by the image input device.

FIG. 9 shows a flow of processing in the image processing apparatus when performing an inter-lead foreign matter inspection by a method of providing a scan line using the inspection apparatus of FIG. The image capturing unit 1 captures the reference image and the image to be inspected into the image processing device using the image input device. The reference image is registered in the registered image memory 2, and the image to be inspected is registered in the image memory 3. The pattern matching circuit 4 performs pattern matching on the reference image and the image to be inspected, and detects the position of the lead in the image to be inspected.

The lead edge circuit 5 creates projections in the X and Y directions for a region including each lead detected by the pattern matching circuit 4, and determines the tip, root, and side edge of each lead. At the same time, the lead edge circuit 5 calculates a threshold value for a region including each lead.

The scan line setting circuit 6 sets a scan line between the leads based on the position of the side edge of the lead detected by the lead edge circuit 5. For example, as shown in FIG. 10, the scan lines 61 are disposed at or near a location that divides the space between the leads 60 into one third.

[0009] The defect determination circuit 7 checks whether or not a pixel having a density equal to or higher than the threshold exists on the scan line. If there is a pixel having a density equal to or higher than the threshold value on the scan line, the defect determination circuit performs a defect determination that a foreign substance exists between the leads.

[0010]

According to the method of providing a scan line, as shown in FIG. 11, even when a foreign substance 63 such as dust different from a foreign substance 62 such as a lead burr or a tie bar exists between leads, a scan is performed. Line 61
As long as the foreign substance 63 exists on the upper side, the defect determination is performed.

The purpose of inspecting foreign matter between leads is to detect foreign matter 62 such as lead burrs and tie bars which adversely affect the IC, and detect dust and noise between leads to judge a defect. Otherwise, an accurate inter-lead foreign matter inspection cannot be performed.

The method of masking leads using an average density as shown in FIG. 12 can provide a detailed inspection result, but has disadvantages such as a long inspection time and high cost.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned drawbacks, and an object of the present invention is to easily detect foreign matter between leads such as lead burrs and tie bars which are originally to be detected and to erroneously detect dust and noise. An object of the present invention is to provide a method for inspecting foreign matter between leads, which does not detect and determine a defect.

[0014]

In order to achieve the above object, an inspection apparatus according to the present invention comprises: means for capturing an image of an IC; and a device parallel to the side of the lead at a predetermined distance from an edge of the side of the lead of the IC. Means for setting a proper scan line, means for performing labeling processing on a range from the edge of the lead or its vicinity to the scan line when pixels having a predetermined density value or more exist on the scan line, and the labeling Means for determining the size of a region of pixels having the predetermined density value or more obtained by processing in the direction perpendicular to the side surface of the lead, and the size of the region in the direction perpendicular to the side surface of the lead is the edge of the lead. Means for determining that a foreign substance exists between the leads when the distance is substantially equal to the range from the vicinity thereof to the scan line. .

The recording medium of the present invention includes a step of capturing an image of an IC, a step of setting a scan line parallel to the side of the lead at a predetermined distance from an edge of the side of the lead of the IC, When a pixel having a predetermined density value or more is present, a step of performing a labeling process on a range from the edge of the lead or its vicinity to the scan line, and a pixel having the predetermined density value or more obtained by the labeling process Determining the size of a region in a direction perpendicular to the side surface of the lead; and the size of the region in a direction perpendicular to the side surface of the lead substantially falls within a range from the edge of the lead or the vicinity thereof to the scan line. And a step of determining that a foreign object exists between the leads when the It is.

In the method for detecting foreign matter between leads according to the present invention, a step of capturing an image of an IC, a step of setting a scan line parallel to the side surface of the lead at a predetermined distance from an edge of the side surface of the lead of the IC, Performing a labeling process for a range from the edge of the lead or the vicinity thereof to the scan line when there are pixels having a predetermined density value or more on the scan line; and Determining a size of a region composed of pixels in a direction perpendicular to the side surface of the lead; and a range of the size of the region in a direction perpendicular to the side surface of the lead from the edge of the lead or the vicinity thereof to the scan line. Determining that there is a foreign substance between the leads when substantially equal to

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a method for detecting foreign matter between leads according to the present invention will be described in detail with reference to the drawings. FIG.
1 shows an outline of an inspection apparatus used when conducting a foreign matter inspection between leads according to the present invention.

Reference numeral 11 denotes an image input device.
It can be composed of a CD camera, a video camera, a scanner, and the like. Reference numeral 12 denotes an illumination device, which can be configured by, for example, fluorescent lamp illumination, ring illumination, LED illumination, and the like. Reference numeral 13 denotes an I to be inspected object (sample)
C. 14 is an IC captured by the image input device
Is an image processing apparatus that performs a predetermined process on the image.

FIG. 2 shows a portion or a circuit for executing each processing in the image processing apparatus of FIG. FIG.
3 shows the operation of the image processing apparatus. Image capture unit 1
Then, using an image input device, an IC (reference IC, inspected IC) as shown in FIG. 4 is imaged and taken into the image processing apparatus as a reference image and an inspected image. The reference image is registered in the registered image memory 2, and the image to be inspected is stored in the image memory 3.
Registered in. The pattern matching circuit 4 performs pattern matching on the reference image and the image to be inspected, and detects the position of the lead in the image to be inspected (Step S).
T1 to ST3).

As shown in FIG. 5, the lead edge circuit 5 creates projections in the X and Y directions with respect to the area A including each lead 10 detected by the pattern matching circuit 4, and generates the tip, base, Find each side edge. At the same time, the lead edge circuit 5
Calculates a threshold value for distinguishing a foreign matter from a background in an area including each lead (step ST4).

As shown in FIG. 6, a labeling area acquisition circuit 8 scans a scan line 20 parallel to the side of the lead 10 between the leads 10 based on the position of the side edge of the lead 10 detected by the lead edge circuit 5. Set.
For example, the scan line 20 has a 1/3
Is arranged at or near the location where the image is divided. Further, the labeling area acquisition circuit 8 sets an inspection area (hereinafter, labeling area) B for performing a labeling process. The size of the labeling area B is, for example, the width of the lead 10
, And the length is from the edge of the side surface of the lead 10 (the point on the lead side several pixels away from the position recognized as the edge) to the scan line 20 (step ST5).

The defect determining circuit 9 firstly determines a pixel having a density equal to or higher than a threshold value on the scan line 20 (defective pixel).
It is checked whether or not exists (step ST6). If there is no pixel (defective pixel) having a density equal to or higher than the threshold value on the scan line 20, a good judgment is made (step ST9). If there is a pixel (defective pixel) having a density equal to or higher than the threshold value on the scan line 20, the defect determination circuit 9 performs a labeling process in the labeling area B set by the labeling area acquisition circuit 8 ( Step ST7).

The labeling process is a labeling area B
Is a process of detecting, for each region, a region composed of pixels having a density equal to or higher than a threshold value. Also,
In the present invention, in order to detect whether or not a pixel (defective pixel) having a density equal to or higher than the threshold value on the scan line 20 is connected to the edge of the side surface of the lead 10, the defect determination circuit 9 performs the detection by a labeling process. The size in the X direction (the direction perpendicular to the side surface of the lead) of each of the regions thus obtained is obtained.

When at least one of the regions detected by the labeling process has N pixels (a range substantially equal to the length of the labeling area) in the X direction (the direction perpendicular to the side surface of the lead). Recognizes that the defective pixel on the scan line 20 is connected to the edge of the side surface of the lead 10, and determines that there is a foreign substance (lead burr, tie bar, etc.) between the leads 10 that affects the operation of the IC. A determination is made (step ST8).

When the length in the X direction (the direction perpendicular to the side surface of the lead) is less than N pixels for all of the regions detected by the labeling process, I
A good determination is made on the assumption that there is no foreign matter (lead burrs, tie bars, etc.) that affects the operation of C (step ST9).

FIG. 7 shows a specific example of the pattern of the judgment in the defect judgment circuit 9. For example, when a foreign substance such as C1 exists, the foreign substance C1
Since it is on 0, labeling processing is performed. When the labeling process is performed, it is known that the size in the X direction of the region composed of the pixels equal to or larger than the threshold value representing the foreign substance C1 is N pixels. it can. Therefore, a failure determination is made.

When a foreign substance such as C2 exists,
Since the foreign matter C2 exists on the scan line 20, a labeling process is performed. By performing the labeling process, it is found that the size in the X direction of a region including pixels equal to or larger than the threshold value representing the foreign substance C2 is smaller than N pixels, and therefore, the foreign substance can be recognized as being caused by dust or noise. . Therefore, as long as there is no other defective pixel, a good judgment is made.

On the other hand, when a foreign substance such as C3 exists,
This foreign substance C3 does not exist on the scan line 20.
Therefore, no labeling process is performed, and a good determination is made unless there is another defective pixel. The foreign substance such as C3 is considered to be a lead burr or tie bar extending from the lead 10, but is short and does not affect the operation of the IC.

By the way, for all leads of the IC,
After the pass / fail judgment is completed, the same process is performed for the next IC (step ST10). According to such a method, foreign matter between leads such as lead burrs and tie bars can be distinguished from dust and noise, and the inspection of foreign matter between leads can be performed accurately and easily.

[0030]

As described above, according to the inter-lead foreign matter inspection method of the present invention, when a defective pixel is present on a scan line, the labeling process in the labeling area and the continuity of the defective pixel ( Confirmation as to whether or not it has reached the lead edge). As a result, dust and noise can be distinguished from foreign matter between leads, such as lead burrs and tie bars, which are originally to be detected, and foreign matter between leads can be inspected accurately and easily.

[Brief description of the drawings]

FIG. 1 is a view schematically showing an inspection apparatus for performing a foreign matter inspection between leads according to the present invention.

FIG. 2 is a block diagram illustrating a configuration of the image processing apparatus of FIG. 1;

FIG. 3 is a flowchart showing the operation of the image processing apparatus of FIG. 1;

FIG. 4 is a diagram of the IC viewed from above.

FIG. 5 is a diagram showing detection of a lead edge.

FIG. 6 is a diagram showing scan lines and labeling areas.

FIG. 7 is a diagram showing determination of good or bad of a lead of an IC;

FIG. 8 is a view schematically showing a conventional inspection apparatus for performing an inter-lead foreign matter inspection.

FIG. 9 is a block diagram illustrating a configuration of the image processing apparatus in FIG. 8;

FIG. 10 is a diagram showing a technique using scan lines.

FIG. 11 is a diagram showing defective pixels on a scan line.

FIG. 12 is a diagram showing a technique for masking a lead.

[Explanation of symbols]

1: image capture unit, 2: registered image memory, 3: image memory, 4: pattern matching circuit, 5: read edge circuit, 6: scan line setting circuit, 7, 9: defect determination circuit, 8: labeling area acquisition circuit , 10, 60, 91: lead, 11: image input device, 12: illumination device, 13: inspection sample, 14: image processing device, 20, 61: scan line, 30: IC body (package), 62, 63: Bad pixels, 92: background.

──────────────────────────────────────────────────続 き Continued on the front page (58) Fields surveyed (Int.Cl. ⁷ , DB name) G01N 21/88 G01N 21/95 G01B 11/02 G06T 7/00

Claims (3)

(57) [Claims] A means for capturing an image of an IC;
Means for setting a scan line parallel to the side surface of the lead at a predetermined distance from the edge of the side surface of the lead, and when a pixel having a predetermined density value or more exists on the scan line, the edge of the lead or its vicinity Means for performing a labeling process on a range from the scan line to the scan line; means for obtaining a size of a region including pixels having the predetermined density value or more obtained by the labeling process in a direction perpendicular to a side surface of the lead; Means for determining that a foreign substance exists between the leads when the size of the lead in the direction perpendicular to the side surface thereof is substantially equal to the range from the edge of the lead or the vicinity thereof to the scan line. An inspection apparatus characterized by the above-mentioned. 2. A step of capturing an image of an IC, a step of setting a scan line parallel to a side surface of the lead at a predetermined distance from an edge of a side surface of the lead of the IC, and a step of setting a predetermined density value or more on the scan line. Performing the labeling process for the range from the edge of the lead or the vicinity thereof to the scan line, when the pixel exists, and the lead of the region including the pixels having the predetermined density value or more obtained by the labeling process. Determining the size in the direction perpendicular to the side surface, and when the size of the region in the direction perpendicular to the side surface of the lead is substantially equal to the range from the edge of the lead or the vicinity thereof to the scan line, Determining that a foreign substance is present between the leads. Recording medium. 3. A step of capturing an image of an IC, a step of setting a scan line parallel to the side surface of the lead at a predetermined distance from an edge of a side surface of the lead of the IC, Performing the labeling process on the range from the edge of the lead or the vicinity thereof to the scan line, when the pixel exists, and the read of the region of the pixel having the predetermined density value or more obtained by the labeling process. Determining the size in the direction perpendicular to the side surface, and when the size of the region in the direction perpendicular to the side surface of the lead is substantially equal to the range from the edge of the lead or the vicinity thereof to the scan line, Determining that foreign matter is present between the leads.