JPH11177009A - Method for checking lead shape and device therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method and device for checking the lead shape for precisely detecting deformation of a lead, and for detecting foreign matters attached on the lead. SOLUTION: A picture data of an IC package P in which plural leads are projected from the side are obtained by a camera 2, and the picture data of the IC package P are digitally processed so that an area in which the reflected light quantity of the IC package P is large can be extracted. In this case, whether or not the arrangement of each area is made to correspond to the feature of normal lead shape, and the corresponding area is recognized as a lead. Then, the flatness of the lead is detected based on the position of each area recognized as the lead.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method and an apparatus for inspecting a lead shape of a semiconductor device.

[0002]

2. Description of the Related Art Normally, in the process of manufacturing a semiconductor device, the shape of leads of an assembled IC package is inspected. In recent years, in the inspection of lead shapes, there has been a method in which a lead is imaged by an image pickup device and a non-defective / defective product of the lead shape is determined based on the image information of the imaged lead because of a demand for a highly accurate lead shape. It is being adopted rapidly. The inspection items of the lead shape inspection include, for example, the following items.・ Lead pitch inspection ・ Lead flatness inspection ・ Lead foreign matter adhesion inspection

In the lead pitch inspection, the interval between each lead is inspected. The lead flatness inspection checks whether the lead floats and sinks with respect to the lead ground plane. In the lead portion foreign matter adhesion inspection, it is inspected whether solder, resin, or other foreign matter has adhered to the leads. As described above, these inspections are performed by imaging the IC package with the imaging device and processing the image information of the imaged leads in a predetermined procedure.

[0004]

The lead pitch inspection is performed by
Since each lead is imaged by an imaging device from above the IC package and the interval between each lead can be directly identified from the imaged data, there is no particular technical problem. In the lead flatness inspection, the flatness of each lead cannot be directly measured based on the measurement result of the position of the tip of each lead from above the IC package. For this reason, when inspecting the flatness of the lead portion using image processing from above the semiconductor device, the difference in the length of the lead end portion or the length from the mold portion of the IC package is measured. The measured values are converted into flatness using a relational expression between the tip length and the actual flatness, and the inspection is performed. However, depending on the type of lead deformation, there are cases where there is no difference between the lead end portions, where the tolerance of the product dimensions is large and it is difficult to set a reference value, and there are cases where inspection cannot be performed by numerical measurement. Further, the lead portion foreign matter adhesion inspection is detected by a pattern matching process or the like based on the image data of the lead.
However, the pattern matching process is not suitable for practical use because it requires a long time and a complicated program.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems, and can detect lead deformation with high accuracy.
An object of the present invention is to provide a lead shape inspection method and an inspection device capable of detecting a foreign substance attached to a lead.

[0006]

According to the present invention, an image pickup device acquires image data of an IC package having a plurality of leads protruding from a side portion, and uses the image data of the IC package to obtain an area having a large amount of reflected light of the IC package. Extracting, and judging whether or not the arrangement of the area having a large amount of reflected light corresponds to the characteristic of a normal lead shape, and recognizing the corresponding area as a lead. Detecting the flatness of the leads based on the positions of the respective regions.

In the present invention, the lead is recognized by judging whether or not the arrangement of the extracted area corresponds to the characteristic of the normal lead shape. Can be detected. Then, the step of recognizing the lead serves as a rough filter for detecting large deformation of the lead shape, and improves the detection accuracy of the next step of detecting the flatness of the lead.

[0008] The step of detecting the flatness of the lead includes the steps of detecting the position of the tip of each lead based on the position of each area recognized as the lead, and the step of detecting the tip of each lead provided on one side of the IC package. Comparing the position with the leading end position of each lead provided on the opposite side to determine whether or not the difference between the detected leading end positions is within a predetermined range.

The step of detecting the flatness of the lead further includes the step of detecting a difference between the positions of the tips of the leads between adjacent leads and determining whether or not the difference between the positions of the tips of the leads is within a predetermined range. Have.

The present invention further comprises the step of judging whether or not foreign matter is attached to the lead based on the area of each of the regions recognized as the lead.

[0011]

Embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 is a configuration diagram showing an embodiment of a lead shape inspection apparatus according to the present invention. The inspection device 1 illustrated in FIG. 1 includes a camera 2, an illumination device 4, and an image data processing device 6. The lighting device 4 irradiates the IC package P with light. The use of the lighting device 4
In order to accurately identify the lead L of the IC package P,
This is because it is necessary to keep the IC package P at an appropriate brightness. The IC package P has a plurality of leads L on its side.
The lead L is made of a material such as aluminum, for example, and has a white color. The IC package P portion is made of a mold resin having a color such as black. Therefore, when light is applied to the IC package P, the amount of light reflected from the leads L is large, and thus the leads L can be identified. The camera 2 is arranged above the IC package P, receives light from the IC package P, and converts the light into an electric signal. The image data processing device 6 binarizes or multi-values the light amount based on the electric signal from the camera 2 and performs various processes based on the digitized signal.

Next, an example of the IC package P inspected by the inspection apparatus having the above configuration will be described. FIG.
Is a partial cross-sectional view of an IC package P having so-called gull-wing-shaped leads. In FIG. 2, when the illumination is performed from above the IC package P, the amount of reflected light from the regions R1 and R2 of the shoulder opening La and the tip end Lb of the gull wing-shaped lead L increases. Accordingly, when the camera 2 captures an image of the IC package P and digitally processes the image data, when the leads L of the IC package P have a normal shape, the image data of the IC package P becomes as shown in FIG. The image in FIG. 3 is an island-shaped region X corresponding to the shoulder opening La of the lead L of the IC package P.
a and a region Xb corresponding to the tip Lb are arranged in a shape corresponding to each lead L.

The items of the IC package inspection described above include, for example, a lead pitch inspection, a lead flatness inspection, and a lead foreign matter adhesion inspection. In the lead pitch inspection, as shown in FIG. 4, the distance between islands in the arrangement direction of each lead is detected, and if this distance is out of a predetermined range, the lead of the IC package is determined to be defective. Specifically, the image data processing device 6 can detect the distance between the regions Xa and Xb shown in FIG. In the lead portion foreign matter adhesion inspection, it is inspected whether solder, resin, or other foreign matter has adhered to the leads L. In the lead flatness inspection, as shown in FIG. 4B, floating and sinking of the lead L with respect to the lead ground plane are inspected.

In the lead flatness inspection, deformation of the lead L related to lifting and sinking may be caused, for example, as shown in FIG. 5 by lifting (sinking) of one of the plurality of leads. In this case, a difference δ occurs between the position of the leading end of the lifted lead L and the other lead. Therefore, such deformation can be detected by detecting the tip position of the lead L.

As shown in FIG. 6 or FIG.
It is conceivable that each lead L on one side of the package may similarly float or sink. In this case, the difference δ between the tip positions of the leads L on one side of the IC package hardly occurs. Therefore, the deformation of the lead cannot be detected by comparing the tip positions of the leads L. In this case, the tip position of each lead L and the IC as shown in FIG.
It is also conceivable to compare the package P with reference dimensions at the time of design. However, in practice, since the reference dimension at the time of designing the IC package P includes a dimensional tolerance (100 μm in FIG. 8), this dimensional tolerance is generally large, and is larger than the change in the tip position caused by the deformation of the lead. large. For this reason, even if the reference dimension at the time of designing the IC package P is compared with the detected tip position of the lead L, it is not possible to accurately detect the floating or sinking of the lead L.

Next, an example of processing by the inspection apparatus having the above configuration will be described with reference to a flowchart shown in FIG. First, as shown in FIG.
The camera 2 captures an image of the IC package P inside. When the obtained image data is digitally processed, for example, image data as shown in FIG. 9B is obtained. That is, in the image data shown in FIG.
The lead L (areas Xa and Xb), which has a large amount of reflected light, and other areas composed of other reflective objects are extracted (step S).
1).

Next, an average value SM of the areas of the extracted regions is calculated (step S2). The average value SM of the area of each area can be obtained by calculating the sum of the areas of each area and dividing the sum by the number of each area.

Next, only the areas falling within a predetermined range are selected from the average value SM of the areas of the respective areas (step S).
3). That is, those exceeding a certain upper and lower limit range with respect to the average value SM are removed. Further, as shown in FIG. 9B, regions Xc and X having particularly large lengths in the X and Y directions are provided.
d is also removed. As a result, image data as shown in FIG. 10 is obtained. In this state, the above-described lead pitch inspection can be performed. Specifically, each area Xa, X
This can be done by detecting the distance between b.

Here, the image data shown in FIG. 10 is data in the case where the lead shape is normal, and the areas Xa and Xb corresponding to the shoulder opening La and the tip Lb of the lead L are arranged at a predetermined interval. It is in a state of being left. On the other hand, when the lead L of the IC package P has a shape defect as shown in FIGS. 5 to 7, for example, the regions Xa and Xb are arranged at predetermined intervals as shown in FIG. Image data in the locked state cannot be obtained. For example, as shown in FIG.
If the leads L on one side of the IC package P are similarly lifted, as shown in FIG. 11, the regions Xa and Xb are arranged at predetermined intervals on the other three sides. However, a single area Xe is arranged on the one side.

From this, it is determined whether the regions Xa and Xb are arranged at predetermined intervals, that is, whether the regions Xa and Xb are formed according to the characteristics of the gull-wing-shaped lead L (step). S4). Area Xa, X
If b is formed, the areas Xa and Xb are recognized as a read (step S5).

For example, as shown in FIG. 11, when the regions Xa and Xb are not formed, the IC package P is determined to be defective (step S6). In this case, for example, the number N of leads L of the IC package P is registered in advance, and the number of leads actually detected is smaller than this number N, so that it is possible to easily determine.

By the steps up to this point, it is possible to select an IC package in a state where all the leads on one side are floating or a state where there is a large floating or sinking as shown in FIGS. . That is, the steps so far play a preparatory role in the subsequent inspection process.

Next, the position of the leading end of the lead L of the IC package whose lead has been recognized is detected (step S).
7). The leading end position of the lead L is detected by detecting the coordinates in the X and Y directions at the leading end position of the area Xb corresponding to the leading end Lb of the lead L.

Next, the tip positions of the leads L are compared between the adjacent leads L (step S8). In the above-described steps, it is possible to detect a lead in which floating or sinking has significantly occurred. In this step, the tip positions of the leads L are compared between adjacent leads L. If the difference between the tip positions of both leads exceeds a predetermined range, the I
It is determined that the lead shape of the C package P is defective.
That is, even when there is a small difference between the tip positions of the adjacent leads L, the deformation of the leads L can be detected.

Next, using the X and Y coordinate data of these lead tip positions, the average coordinates of the tip positions of the leads L on each side of the IC package P are determined. The average coordinates are compared for each opposite side (step S9). When the difference between the average coordinates of the tip coordinate positions of the leads L between the opposite sides exceeds a certain reference, it is considered that the leads on one of the sides are deformed. This makes it possible to detect lead deformation that cannot be detected by detecting the difference between the tip positions of the adjacent leads L. In addition, although a method of inspecting the tip position of the lead L based on the dimensions at the time of designing the actual product can be considered, as shown in FIG. 8, the tolerance range is usually as large as about ± 100 μm. If the floating amount is converted based on the difference in the length of the lead, it is necessary to judge with an accuracy of about 50 to 60 μm, so that it cannot be applied.

As described above, according to the present embodiment, the IC
An image processing inspection from above the package P can detect the deformation of the leads such as floating or sinking, and the inspection of the lead flatness can be performed with high accuracy. Also, utilizing the characteristics of the shape of the gull wing-shaped lead L, it is determined whether the number of the regions Xa and Xb is appropriate for each lead L, and whether or not the regions Xa and Xb have an appropriate area is determined. , It is possible to easily detect the deformation of the lead L, which cannot be detected by detecting the position of the tip of the lead, such as floating or sinking. In addition, after confirming the number and area of the regions Xa and Xb, the tip position of the lead L is detected, and furthermore, the deformation of the lead L is detected, so that the detection accuracy of the lead flatness is greatly improved. Also, when detecting the tip position of the lead L,
Since the lead deformation is determined not based on the absolute distance from the mold part of the IC package P but based on the difference between the adjacent leads L and the difference between the opposite sides, the lead is not affected by the dimensional tolerance at the time of design, and the lead is more precisely. Inspection of flatness can be performed.

Up to this point, the inspection of the lead flatness has been mainly described. Hereinafter, the inspection of the lead portion for foreign matter adhesion will be described. First, in the above-described inspection processing, the regions Xa, Xb
Is recognized as a lead, and the area of each of the regions Xa and Xb is calculated. At this time, if the area of each of the regions Xa, Xb does not fall within the predetermined range, the region Xa, Xb
It is determined that the foreign matter is attached to the lead L corresponding to.
Therefore, a complicated process such as a pattern matching process is not required to perform the lead portion foreign matter adhesion inspection, and the region X
By checking the areas a and Xb, it is possible to efficiently detect the adhesion of solder, resin, and other foreign substances adhered to the leads L, shorten the processing time, and simplify the program.

[0028]

According to the present invention, the inspection of the flatness of the leads can be accurately performed by the image processing inspection from above the IC package. In addition, the floating or sinking of the lead can be accurately detected only by inspection from above the IC package, so that a single facility such as a commonly used lead shape inspection machine is not required. Therefore, the camera and the lighting device can be installed anywhere if there is a space for the installation, and the lead shape inspection function can be attached to the existing facility later, so that the quality of the lead shape can be improved even in the existing facility.

In the inspection of the lead shape, complicated program processing is not required, and the processing time can be very short. In addition, it is possible to detect a product different from a normal lead state due to peculiar deformation of the lead portion other than the lead flatness and foreign matter adhesion detection without including a special detection program. In addition, even if the lead tip flat area decreases due to poor lead formation and the lead tip area becomes small, defective molding can be detected in the form of insufficient tip area, and similarly deformation of the shoulder opening can be detected.

[Brief description of the drawings]

FIG. 1 is a configuration diagram showing an embodiment of a lead shape inspection apparatus according to the present invention.

FIG. 2 is a partial cross-sectional view of an IC package P having a gull-wing-shaped lead.

FIG. 3 is an explanatory diagram showing an example of a state in which an image of an IC package is captured by a camera and the image data is digitally processed;

FIG. 4 is a diagram for explaining items of IC package inspection.

FIG. 5 is an explanatory diagram showing an example of deformation of a lead related to lifting and sinking in a lead flatness inspection.

FIG. 6 is an explanatory diagram showing another example of deformation of a lead related to lifting and sinking in a lead flatness inspection.

FIG. 7 is an explanatory view showing still another example of the deformation of the lead related to the lifting and sinking in the lead flatness inspection.

FIG. 8 is an explanatory diagram showing reference dimensions at the time of designing the IC package P.

FIG. 9 is an explanatory diagram showing image data obtained by capturing an image of an IC package P with a camera within a predetermined range M and digitally processing the obtained image data.

FIG. 10 is an explanatory diagram illustrating image data obtained by performing predetermined processing on the image data illustrated in FIG. 9;

FIG. 11 is an explanatory diagram illustrating an example of image data in a case where a lift has occurred in each of the leads L on one side of the IC package P;

FIG. 12 is a flowchart illustrating an example of a process performed by the lead shape inspection apparatus according to the present invention.

[Explanation of symbols]

2 camera, 4 lighting device, 6 image data processing device,
P: IC package, L: Lead.

Claims (9)

[Claims] An image pickup device acquires image data of an IC package having a plurality of leads protruding from a side by an image pickup means.
Extracting a region of the IC package having a large amount of reflected light from the image data of the C package; and determining whether or not the arrangement of the region of the large amount of reflected light corresponds to a characteristic of a normal lead shape. Recognizing the read area as a lead, based on the position of each area recognized as the lead,
Detecting the flatness of the lead. 2. The method according to claim 1, wherein the step of detecting the flatness of the lead includes the steps of: detecting a tip position of each lead based on a position of each area recognized as the lead; 2. The method according to claim 1, further comprising: comparing the leading end position of the lead with the leading end position of each lead provided on the opposite side to determine whether a difference between the detected lead leading end positions is within a predetermined range. Inspection method of lead shape. 3. The step of detecting the flatness of the leads includes the step of detecting the difference between the positions of the tips of the leads between adjacent leads and determining whether the difference between the positions of the tips of the leads is within a predetermined range. The inspection method of a lead shape according to claim 2, further comprising: 4. The lead shape inspection method according to claim 1, further comprising the step of determining whether or not foreign matter is attached to the lead based on the area of each of the regions recognized as the lead. 5. A step of calculating an average value of an area of each of the areas after extracting an area having a large amount of reflected light of the IC package; and, in each of the areas, an area of a predetermined range from the average value. 2. The method according to claim 1, further comprising the step of selecting only an area that falls within the range. 6. The lead shape inspection method according to claim 1, further comprising the step of selectively excluding, from the selected areas, areas whose lengths in a predetermined direction exceed a predetermined range. 7. The lead has a gull wing shape having two bent portions, and each region recognized as the lead is formed of a region corresponding to a shoulder surface and a tip end surface of the lead. Item 2. The lead shape inspection method according to Item 1. 8. When judging whether or not the arrangement of each of the selected areas corresponds to a feature of a normal lead shape, the uncorresponding area is determined to have a deformed lead of the area. The lead shape inspection method according to claim 1, wherein the judgment is made. 9. An illuminating means for irradiating light to an IC package having a plurality of leads protruding from a side portion; an imaging means for obtaining image data of the IC package from light reflected from the IC package; Image data processing means for digitally processing image data from the image data processing means, wherein the image data processing means includes: an extraction means for extracting a plurality of areas with a large amount of reflected light from image data from the imaging means; and each of the areas A feature determining means for determining whether the arrangement of the lead corresponds to the feature of the shape of the lead, and a feature determining means for recognizing the corresponding area as the lead; and a flatness of the lead based on the area recognized as the lead. A flatness detecting means for detecting whether or not a foreign substance is attached to the lead based on an area of each of the regions recognized as the lead. An inspection device for a lead shape, comprising: an attachment determining unit.