JP2715897B2 - IC foreign matter inspection apparatus and method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus and a method for detecting foreign matter such as resin waste, fiber waste and solder waste attached to IC leads.

[0002]

2. Description of the Related Art As a conventional inspection method for detecting foreign matter adhering to an IC, there is, for example, an "IC lead detection method" disclosed in JP-A-61-66908.

FIG. 10 is a block diagram showing this conventional inspection method. In this conventional inspection method, the inspection target component I
An image sensor 31 for inputting the image of C, a frame memory 32 for storing the image input from the image sensor 31, and an IC that performs arithmetic processing from the image data from the frame memory 32
When it is detected that foreign matter is attached to the lead of
And an arithmetic processing unit 33 that outputs a C reject signal.

[0004] The detection of foreign matter adhering to an IC lead in this conventional inspection method is as follows. Image data output from the frame memory 32 is input to the arithmetic processing unit 33,
The lead part is "1" and the background is "
After the binarization process is performed so as to be a dot of "0", the binarized data is "1" in the longitudinal direction of the lead in an area on the lead.
It is checked whether there is a portion that changes from "0" to "1", and if so, it is determined that foreign matter has adhered to the IC lead, and a defect signal is output.

[0005]

In the above-described conventional method for inspecting foreign matter adhering on an IC lead, the entire lead is binarized at the same binarization level to make the lead portion "1". Therefore, the binarization level must be set low so that the slope of the lead having a small amount of reflected light is "1". Therefore, when a foreign matter having a high transmittance, such as fiber waste, or a foreign matter, such as a resin waste having a good reflectance, adheres to the lead, the difference in the gray level between the lead portion and the foreign matter portion of the captured image is small, so that the binary value is obtained. It is difficult to set only the foreign matter portion to "0" in the lead portion of the structured image, and there is a disadvantage that foreign matter cannot be detected.

In addition, the above-described conventional inspection method has a defect that foreign substances attached between leads cannot be detected.

[0007]

According to the IC foreign matter inspection apparatus of the present invention, a lead to be inspected comprises a shoulder portion of a flat portion on the mold side, a flat portion on the tip side, and a slope portion located therebetween. A camera for capturing an image of an IC, AD conversion means for inputting image data from the camera, performing AD conversion and outputting grayscale image data, and
An inspection area extracting means for extracting inspection area grayscale image data in a range including all the leads of one side of C; and only the flat portion and shoulder portion of the lead, which receives the inspection area grayscale image data and receives a large amount of reflected light, from the camera. A first binarizing means for binarizing to be "1", and a binarized image data binarized by the first binarizing means being input and being perpendicular to a longitudinal direction of the lead. A projection unit for outputting X projection data obtained by measuring the number of “1” pixels in each image element sequence in the X direction; and a part of the inspection area gray image data where the X projection data is smaller than a predetermined value. A portion corresponding to the center portion is a slope image and a portion larger than the predetermined value and corresponding to the mold side portion of the IC is a shoulder image and a portion larger than the predetermined value and corresponding to a tip side portion of the lead. The flat part image and The shoulder area image, the slope area image, and the flat area image are each binarized at a unique binarization level, and a pixel of “1” is identified as the lead part. A divided region-based foreign matter detecting means for detecting foreign matter attached to the lead.

In the method for inspecting foreign matter of an IC according to the present invention, the lead to be inspected is imaged by a camera of an IC formed of a shoulder of a flat portion on the mold side, a flat portion on the tip end, and a slope portion located between them. From the A / D converted gray image data, inspection area gray image data in a range including all the leads of one side of the IC is cut out, and the camera receives the inspection region gray image data with a large amount of reflected light and the flat portion of the lead and X-projection data obtained by measuring the number of “1” pixels in each pixel row in the X-direction perpendicular to the longitudinal direction of the lead of the binarized data binarized so that only the shoulders become “1” A slope image of a portion corresponding to the center of the lead in a portion where the X projection data obtained by dividing the inspection area grayscale image data is smaller than the predetermined value, and larger than the predetermined value; The shoulder image of the portion corresponding to the field side and the flat portion image of the portion larger than the predetermined value and corresponding to the tip side of the lead are binarized at a unique binarization level for each of the leads. And detecting foreign matter attached to the lead.

[0009]

Next, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a block diagram showing an IC foreign matter inspection apparatus according to one embodiment of the present invention.

In FIG. 1, a camera 1 is an IC to be inspected.
The second lead 21 is imaged and analog image data a is output. The camera 1 is placed on the upper surface side of the IC 2 to be inspected, and illuminates the IC 2 by illumination (not shown) on a ring centered on the camera 1. The AD conversion means 3 receives the analog image data a, performs AD conversion, and outputs grayscale image data b. The inspection area cutout means 4 cuts out, from the grayscale image data b, grayscale image data of a portion including all the leads 21 for one side of the IC 2 in a preset range,
The inspection area gray image data c is output. Image storage means 5
Stores the inspection area grayscale image data c and outputs this as storage data. The first binarizing means 6 sets the slope 24 of the lead 21 in which the grayscale image data of one side is preset by the storage data d to “0” and the flat part 2 of the lead 21.
3 is converted into binarized image data e by a first binarization level that sets “1” to “1”, and is output. The X projection means 7 measures the number of “1” pixels of the binarized image data e for each image element sequence in a direction perpendicular to the longitudinal direction of the lead (hereinafter referred to as the X direction) and outputs measurement data f.

The second binarizing means 8 inputs the measurement data f, binarizes the measurement data f at a preset second binarization level, and outputs projection binarization data g. The read area dividing means 9 determines whether “0” and “1” of the
Of the lead 21 from the mold 22 toward the distal end of the lead 21 by using the shoulder 25, the slope 24, and the flat portion 2.
And outputs a read area division signal h for dividing into three areas. The divided area-based foreign matter detection means 10 divides grayscale image data of one side based on the storage data d by the read area division signal h, and sets a binarization level, a read width determination value, and a read interval determination value suitable for each area. Is used to determine foreign matter. The foreign matter detection method is to binarize the binarized data for each area and set “1”
Is compared with the upper limit and lower limit of the read width determination value, and the number of continuous pixels of "0" is compared with the upper limit and lower limit of the read-between determination value, and the number of continuous pixels outside the range of the determination value is determined. If there is, it is determined that foreign matter is attached.

Next, the principle of the IC foreign matter inspection method of this embodiment will be described with reference to FIGS. FIG. 2 to FIG. 9 are views for explaining the principle of lead area division in the IC foreign matter inspection method of the present embodiment.

FIG. 2 is a pattern diagram of the storage data d storing the grayscale image data c of the lead 21 for one side of the IC 2. FIG. 3 is a pattern diagram of the binarized image signal e, and a hatched portion is an area of “1” after binarization. Since the shoulder portion 25 and the flat portion 23 of the lead 21 have high reflectivity, the first binarizing means 6 forms an area of “1”. FIG. 4 is a graph of the measurement data f output from the X projecting means 7, and the vertical axis corresponds to FIG. 3 and indicates the position of the lead 21 in the longitudinal direction. The abscissa indicates the measurement frequency, and the area 23 ′ and the area 25 ′ corresponding to the flat part 23 and the shoulder part 25 of the lead 21 have a value larger than the area 24 ′ applied to the slope part 24. I have. The value of the measurement data f corresponding to the slope portion having a small reflectance is “0” or a value close to “0”. FIG. 5 shows a graph of the binarized projection data g, and the areas H1 and H where “1” of the binarized projection data are continuous.
3 correspond to the flat portion 23 and the shoulder portion 25, respectively.
The area H2 where “0” continues between 1 and H3 is the slope 24
Corresponding to Therefore, in the read area dividing means 9, an area H1 where “1” and “0” of the projection binary data g are continuous.
A lead area division signal h for dividing the longitudinal direction of the lead according to H2 and H3 is output. FIG. 6 is an image obtained by dividing the storage data d input to the divided area-based foreign matter detecting means 10 by the read area division signal h. Each of the flat portion image 26, the slope portion image 27, and the shoulder portion image 28 illustrated in FIG. 6 corresponds to each of the regions H1, H2, and H3 illustrated in FIG.

FIG. 7 is a pattern diagram in which the divided image is binarized at a binarization level preset for each region so that the read portion of each region is "1". Regarding the flat portion image 26 and the shoulder portion image 28 corresponding to the flat portion 23 and the shoulder portion 25 having a large reflectance, a binary value larger than the binarization level of the slope portion image 27 corresponding to the slope portion 24 having a small reflectance. The lead level of the binarized image is set to "1" not only in the flat part image 26 and the shoulder part image 28 but also in the slope part image 27. If a small binarization level is set in the flat part image 26 and the shoulder part image 28 in accordance with the slope part image 27, the foreign matter attached to the shoulder part 25 and the flat part 23 is reflected by the small binarization level. Can detect only foreign matter whose reflectance is equal to or less than that of the lead, and can detect only foreign matter having a large difference between the lead and the reflectance.
6. By increasing the binarization level of the shoulder image 28 from that of the slope image 27 and setting the binarization levels of the flat image 26 and the shoulder image 28 as large as possible, Also, a foreign matter having a small difference between the lead and the reflectance can be detected by the shoulder 25.

FIG. 8 is a graph of measurement data obtained by projecting the number of pixels of each image "1" divided and binarized shown in FIG. 7 in a direction parallel to the longitudinal direction of the lead. FIG.
(C) is a graph for the binarized image of each of the flat part image 26, the slope part image 27, and the shoulder part image 28. The horizontal axis in FIG. 8 corresponds to the position in FIG. 7 and indicates the position in the direction perpendicular to the longitudinal direction of the lead. The vertical axis indicates the measurement frequency, and the portion corresponding to the lead has a larger value than between the leads. The value of the measurement data corresponding to between the leads is “0” or a value close to “0”. FIG. 9 (a)
8 (c) are graphs obtained by binarizing the measurement data shown in FIGS. 8 (a) to 8 (c) so that "1" is displayed on the leads and "0" is displayed between the leads. Foreign matter detection is "1"
The number of continuous pixels is compared with the performance value and lower limit of the lead width determination set for each region, and the number of continuous pixels of "0" is compared with the upper and lower limits of the read interval determination value set for each region. If there is a continuous number outside the range of the determination value, it is determined that foreign matter is attached.

For example, the image of the foreign substances 11 and 12 shown in FIG.
If the binarized images 1 and 12 are obtained, deformations as shown in waveforms 13 and 14 occur in the graph of the projection measurement data shown in FIG. 8, and a waveform 15 in the graph of FIG. ,
As shown in FIG. 16, since the number of continuous pixels in the “1” portion becomes abnormally small or large, the number of continuous pixels is compared with the upper limit value and the lower limit value to detect that the number is outside a predetermined range. To determine that foreign matter is attached. Although the width of the flat portion 23 of the lead is smaller than the width of the shoulder portion 25, the upper limit and the lower limit of the lead width determination are determined according to the area of the flat portion image 26, the slope image 27 or the shoulder image 28. By setting to, it is also possible to determine that a foreign substance smaller than the lead width of the shoulder part 25 adheres to the flat part 23 as a foreign substance.

[0018]

As described above, according to the apparatus and method for inspecting foreign matter of an IC according to the present invention, the lead portion of the IC has a shoulder portion having a high reflectance and a small lead width, a slope portion having a low reflectance, and a flat portion having a high reflectance and a large lead width. In order to perform a foreign matter inspection of the read in each of the three regions, it is possible to set a binarization level, a read width determination value, and a read interval determination value suitable for each region. This has the effect of improving the performance of detecting foreign matter on leads with small differences in shading value and foreign matter attached between leads.

[Brief description of the drawings]

FIG. 1 is a block diagram of an IC particle inspection apparatus according to an embodiment of the present invention.

FIG. 2 is a pattern diagram showing storage data d shown in FIG.

FIG. 3 is a pattern diagram of a binarized image signal e shown in FIG. 1;

FIG. 4 is a graph of measurement data f shown in FIG. 1;

FIG. 5 is a graph of the projection binarized data g shown in FIG. 1;

6 is a diagram of an image obtained by dividing the storage data d shown in FIG. 1 by a read area division signal h.

7 is a diagram of an image obtained by binarizing the divided image shown in FIG. 6 by the divided region foreign matter detection means 10 shown in FIG.

FIG. 8 is a diagram of data obtained by projecting the divided and binarized image shown in FIG. 7 in the longitudinal direction of a lead.

FIG. 9 is a diagram of data obtained by binarizing the projected data shown in FIG. 8;

FIG. 10 is a block diagram showing a conventional IC foreign matter inspection method.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Camera 2 IC 3 A / D conversion means 4 Inspection area cutout means 5 Image storage means 6 First binarization means 7 X projection means 8 Second binarization means 9 Lead area division means 10 Foreign substance detection means by division area 21 Lead 22 Mold 23 Flat portion 24 Slope portion 25 Shoulder 26 Flat portion region 23 'Flat portion region 24' Slope portion region 25 'Shoulder region 26 Flat portion image 27 Slope portion image 28 Shoulder image 31 Image sensor 32 Frame memory 33 Arithmetic processing unit a Analog image data b Gray image data c Inspection area gray image data d Storage data e Binary image data f Measurement data g Projection binary data h Read area division signal

Continuation of front page (56) References JP-A-4-310807 (JP, A) JP-A-5-109848 (JP, A) JP-A-2-44233 (JP, A) JP-A-6-194134 (JP) JP-A-5-272931 (JP, A) JP-A-2-42344 (JP, A) JP-A-4-178507 (JP, A) JP-A-4-247635 (JP, A) 5-256622 (JP, A) JP-A-6-222012 (JP, A)

Claims (4)

(57) [Claims] 1. A camera for imaging an IC in which a lead to be inspected comprises a shoulder portion of a flat portion on a mold side, a flat portion on a distal end side, and a slope portion located therebetween, and an image data from the camera. A / D conversion means for inputting and performing A / D conversion and outputting grayscale image data, inspection area cutout means for cutting out inspection area grayscale image data in a range including all leads of one side of the IC from the grayscale image data, First binarizing means for binarizing area grayscale image data so that only the flat portion and the shoulder portion of the lead having a large amount of reflected light received by the camera become "1"; and the first binarization. Projecting means for inputting the binarized image data binarized by the means and outputting X projection data obtained by measuring the number of "1" pixels in each image element sequence in the X direction perpendicular to the longitudinal direction of the lead;
In the inspection area gray image data, a portion corresponding to the central portion of the lead in a portion where the X projection data is smaller than a predetermined value is defined as a slope image and the I value is larger than the predetermined value.
A lead area dividing means for setting a portion corresponding to the mold side portion of C as a shoulder image and a portion larger than the predetermined value and corresponding to the tip end portion of the lead as a flat portion image; and the shoulder image, Foreign matter detection for each divided area for binarizing the slope part image and the flat part image with a unique binarization level to identify a pixel of "1" as a part of the lead and to detect foreign matter attached to the lead And a foreign matter inspection device for an IC. 2. The method according to claim 1, further comprising:
Projection data is obtained by measuring the number of “1” pixels in each pixel row in a direction parallel to the longitudinal direction of the lead for each of the binary image of the slope portion image and the flat portion image, and binarized data of this projection data 2. The IC foreign matter inspection device according to claim 1, wherein whether the width of the "1" portion or the "0" portion falls within a range delimited by a predetermined upper limit or lower limit is detected. 3. A grayscale image data obtained by imaging an IC including a shoulder of a flat portion on a mold side, a flat portion on a tip end side, and a slope portion located between the flat portion on the mold side by a camera and AD-converted. The inspection area grayscale image data in a range including all the leads for one side of the IC is cut out, and the inspection area grayscale image data is reflected by the camera with a large amount of reflected light, and only the flat portion and the shoulder portion of the lead are "1". X obtained by measuring the number of "1" pixels in each pixel column in the X direction perpendicular to the longitudinal direction of the lead of the binarized data binarized as follows.
The projection data is divided by a predetermined value, and the X-projection data obtained by dividing the inspection area grayscale image data is a portion corresponding to the center of the lead in a portion corresponding to the central portion of the lead in a portion smaller than the predetermined value. A shoulder image of a portion corresponding to the mold side portion of the IC and a flat portion image of a portion corresponding to the tip side portion of the lead larger than the predetermined value are respectively binarized at a unique binarization level. A method for inspecting foreign matter of an IC, comprising: digitizing a part of the lead to detect foreign matter attached to the lead; 4. A binarized image obtained by binarizing a slope image, a shoulder image, and a flat image with a unique binarization level, for each pixel column in a direction parallel to the longitudinal direction of the lead.
Projection data obtained by measuring the number of pixels of "1" is obtained, and the width of the "1" portion or "0" portion of the binarized data of the projection data falls within a range delimited by a predetermined upper limit or lower limit. 4. The method according to claim 3, wherein foreign matter attached to the lead is detected based on whether the lead is present or not.