JPH0949715A - Method and apparatus for visual inspection of semiconductor package - Google Patents

Abstract

(57) Abstract: An object of the present invention is to enable highly accurate measurement of a lead length in a gull wing type lead semiconductor package based on an optical image taken. According to the present invention, in a gull wing type lead arranged around a semiconductor package, two types of resolutions Pt, Pb and a camera center position coordinate (X0 , Y
0) is used to calculate each lead length.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention particularly relates to a semiconductor IC package or a semiconductor IC package which is suitable for lead inspection of a gull wing type semiconductor package formed in a gull wing type as leads protruding in each row around the semiconductor IC package. The present invention relates to a semiconductor package appearance inspection method and apparatus for inspecting the appearance of a lead protruding from an electronic component or the like.

[0002]

2. Description of the Related Art Among the visual inspections of semiconductor packages, the first conventional technique for inspecting, for example, the lead shape of a semiconductor package or the surface of a lead is to image the lead and binarize it. Inspection is mainly performed using a binarized black-and-white image. An image storage device described in Japanese Patent Application Laid-Open No. 3-204085 is a second conventional technique for visual recognition by capturing an image for product inspection or the like. The second prior art is for distributing images obtained from a high-resolution camera in a plurality of image memories and storing high-resolution images.
It is not intended for multi-item, high-speed inspection. In addition, as a third conventional technique for inspecting the leads themselves of the semiconductor package, that is, a lead bending amount and a lead floating amount in the visual inspection of the semiconductor package, Japanese Patent Application No. 1-92 is available.
"IC lead inspection device" and Japanese Patent Application No.
-134130 publication, "optical inspection device", Japanese Patent Application No. 63-257816 "lead inspection device" and the like.

[0003]

In the production of semiconductor IC packages or other electronic parts, lead shape inspection, mold shape inspection,
Appearance inspection such as lead surface inspection, mold surface inspection, mark inspection, inter-lead foreign substance inspection is required. These inspections are carried out by installing a visual inspection device for each product type and each inspection item because there are many product types such as semiconductor IC packages and other electronic parts and many inspection items. By the way, the semiconductor package including the leads has a three-dimensional shape (3
When the semiconductor package is imaged by an image pickup means such as an image pickup camera, the two-dimensional shape of the plane can be faithfully captured as an image signal, but the image signal is changed according to the height shape. As a result, an error will occur. However, in any of the above-mentioned conventional techniques, it is possible to accurately measure, for example, the lead length in a semiconductor package having a three-dimensional shape based on an image signal obtained from the image pickup means so that the inspection can be performed with high reliability. , Was not considered enough.

In order to solve the above-mentioned problems of the prior art, an object of the present invention is to provide a semiconductor package including leads having a three-dimensional shape from an image signal picked up by an image pickup means by performing a correction according to a change in height. It is an object of the present invention to provide a semiconductor package appearance inspection method and apparatus capable of accurately calculating the shape and performing inspection with high reliability.
It is another object of the present invention to provide a semiconductor package appearance inspection method and apparatus capable of inspecting a lead portion in a semiconductor package with high reliability. Another object of the present invention is to provide a semiconductor package appearance inspection method and apparatus capable of inspecting a lead portion of a gull wing type semiconductor package with high reliability.

[0005]

In order to achieve the above object, the present invention illuminates at least a lead portion of a semiconductor package installed at a predetermined inspection position, and from at least the lead portion of the illuminated semiconductor package. The optical image based on the reflected light or transmitted light of is detected by the image pickup optical system to detect the image signal of the lead part, and the position coordinates of the tip part and the root part of the lead part obtained from the detected image signal of the lead part Is corrected based on the difference between the resolution at the tip of the lead and the resolution at the root of the lead, and the determination reference value is based on the position coordinates of the tip and the root of the corrected lead. Is a method for inspecting the appearance of a semiconductor package, characterized in that the quality of the leads is determined by comparing with. Further, according to the present invention, at least the lead portion of the semiconductor package installed at a predetermined inspection position is illuminated, and an optical image based on reflected light or transmitted light from at least the lead portion of the illuminated semiconductor package is imaged by an imaging optical system. Then, the image signal of the lead portion is detected, the position coordinates of the tip portion and the root portion of the lead portion are calculated from the detected image signal of the lead portion, and the calculated position coordinates of the tip portion and the root portion of the lead are calculated. And the appearance inspection of the semiconductor package, which determines the quality of the lead by comparing the resolution at the tip of the lead portion and the determination reference value corrected based on the difference between the resolution at the root portion of the lead portion. Is the way.

Further, according to the present invention, in the appearance inspection method for a semiconductor package, the difference between the resolution at the tip of the lead and the resolution at the root of the lead changes depending on the type of the semiconductor package. . Further, the present invention is characterized in that, in the semiconductor package appearance inspection method, the determination standard is changed according to the type of the semiconductor package. Further, according to the present invention, in the appearance inspection method for a semiconductor package, the semiconductor package is a gull wing type. Further, according to the present invention, in the appearance inspection method for a semiconductor package, the illumination light is ring-shaped illumination light. Further, the present invention is based on an illumination optical system that illuminates at least the lead portion of a semiconductor package installed at a predetermined inspection position, and reflected light or transmitted light from at least the lead portion of the semiconductor package illuminated by the illumination optical system. An imaging optical system that captures an optical image to detect the image signal of the lead portion, and a lead for the position coordinates of the tip portion and the root portion of the lead portion obtained from the image signal of the lead portion detected by the imaging optical system. Correction based on the difference between the resolution at the tip of the lead and the resolution at the root of the lead, and based on the position coordinates of the tip and the root of the lead that have been corrected, compared with the determination reference value. An appearance inspection device for a semiconductor package, comprising: an image processing device for determining whether a lead is good or bad.

Further, according to the present invention, an illumination optical system for illuminating at least a lead portion of a semiconductor package installed at a predetermined inspection position, and a light reflected or transmitted from at least a lead portion of the semiconductor package illuminated by the illumination optical system. An imaging optical system that captures an optical image based on light to detect an image signal of the lead portion, and position coordinates of the tip portion and the root portion of the lead portion are calculated from the image signal of the lead portion detected by the imaging optical system. , The calculated position coordinates of the tip portion and the root portion of the lead are compared with the judgment reference value corrected based on the difference in the resolution at the tip portion of the lead portion and the resolution at the root portion of the lead. An appearance inspection device for a semiconductor package, comprising: an image processing device for determining acceptability. Further, according to the present invention, in the image processing apparatus in the appearance inspection apparatus for the semiconductor package, the difference between the resolution at the tip portion of the lead and the resolution at the root portion of the lead is changed and corrected according to the type of the semiconductor package. It is characterized in that it is configured as follows. Further, the present invention is characterized in that, in the image processing apparatus in the appearance inspection apparatus for the semiconductor package, the determination standard is changed according to the type of the semiconductor package. Further, the present invention is characterized in that, in the image processing apparatus in the appearance inspection apparatus for semiconductor packages, a processing program adapted to the gull-wing type is selected from processing programs prepared according to types. . Further, the present invention is characterized in that, in the semiconductor package appearance inspection device, the illumination optical system is configured by a ring-shaped illumination optical system.

Further, the present invention is a method for inspecting the appearance of a semiconductor package, which is arranged on the periphery or on both sides, and has a gull wing type shape at each end of each row.
When the semiconductor package mounted at a predetermined inspection position is illuminated, the leads of the illuminated semiconductor package are imaged,
Each lead length in each imaged row is calculated from the resolution of the lead tip portion, the resolution of the lead root portion, and the camera center position. Further, in the present invention, in measuring the lead length of a semiconductor package, one lead length is measured and set as a reference lead length value, and other adjacent lead lengths are measured from a difference from the reference lead length value. Is characterized by.

[0009]

With the above structure, when the semiconductor package having a three-dimensional shape is picked up by the image pickup means and the image signal is detected,
For example, it is possible to inspect a lead of a semiconductor package with high accuracy by correcting a difference in resolution in the image signal (image data) caused by a change in height between a tip portion and a root portion of the lead portion. it can. Further, with the above configuration, it is possible to inspect, for example, the leads of the semiconductor package with high accuracy by the common processing for the semiconductor packages having many types. Further, with the above configuration, the shape of the lead in the gull wing type semiconductor package can be inspected with high reliability.

[0010]

Embodiments of the present invention will be described with reference to FIGS. The semiconductor packages are roughly classified into a gull wing type and a J lead type. The gull wing type has a QFP (Quad Flat Pa
ckage) and SOP (Small Outline) with leads on both sides
Package). The J lead type has QFJ (Quad Flat J lead Package) with leads in 4 directions.
And SOJ (Small Outline J lead with lead on both sides
Package). By the way, even in the gull wing type, QFP (Quad Flat Package) and SOP (Small O
utline Package), there are different types of package, lead width, lead length, number of pins, etc. even for the same QFP. Also, for the same SOP, package size, lead width, lead length are similar. Well,
There are several types with different numbers of pins.

In FIGS. 1A and 1B, reference numeral 1 denotes a gull-wing type (particularly QFP, which may be a SOP) of a semiconductor package to be inspected.
2a to 2d are leads of the gull wing type semiconductor package 1. The leads 2a to 2d are arranged around the semiconductor package, and the tips (mounting surfaces) thereof are gull-wing type. Reference numeral 3 is a ring-shaped illuminating device for illuminating the semiconductor package 1, and when the semiconductor package 1 is mounted on the suction head 28 and the leads 2a to 2d are inspected as shown in the figure, the respective leads 2a.
It is configured to uniformly illuminate ~ 2d with ring-shaped illumination. Reference numeral 4 is an image pickup camera arranged at a position facing the illuminated semiconductor package 1. 29 is
It is a background plate that darkens the background of the lead portion, and is for making the light illuminated by the ring-shaped lighting device 3 specularly reflected and radiated to the side so that it does not enter the visual field of the imaging camera 4 and becomes completely dark. is there. The imaging camera 4 detects (images) the reflected light from the surface of the lead because it is desired to inspect the surface condition of the lead (dirt or scratch on the surface). Therefore, the transmitted light (passed light) may be imaged (detected) by the imaging camera 4 only by calculating the lead length, the lead width, and the lead pitch. That is, the transmitted light transmitted between the leads specularly reflected by the background plate 29 may be imaged by the imaging camera 4 to obtain an image signal (image data).

Reference numeral 5 is an A / D for converting the image data picked up by the image pickup camera 4 into a digital image signal for processing.
Conversion means. Reference numeral 6 denotes an image memory for recording the imaged content (digital image signal) converted by the A / D conversion means 5. An image processing means (CP) 7 inspects the leads 2a to 2d of the semiconductor package 1 for each column based on the imaged content (digital image signal) taken out from the image memory 6.
U), and the image processing means (CPU) 7 transmits the inspection result as a signal 9 to a lower means (not shown). That is,
The image processing device 21 has the image memory 6 and the image processing means (CPU) 7, and further includes a display device 22 such as a display, an input means including a keyboard 23, a disk 24 and the like, and an inspection determination reference value data. An external storage device 25 for storing and storing various data including
Connected by bus. Further, the suction head 28 is not limited to being mounted on the gull wing type semiconductor package 1, but a J lead type is also mounted. Therefore, since the image processing in the image processing device 21 is naturally different between the gull wing type and the J lead type, the type of the semiconductor package mounted on the suction head 28 (including the types described below) is recognized, and this Information of the recognized type (including type) is input to the image processing device 21. For this type, the input means 23, 2
You may input it using 4.

As for the inspection judgment reference value, the QFP (Quad Flat Package) and S
Different from OP (Small Outline Package),
Even with the same QFP, there are several types with different package dimensions, lead width, lead length, number of pins, etc.
Similarly, in P, there are a plurality of types having different package dimensions, lead widths, lead lengths, pin numbers, etc., which are different from each other. Therefore, in the gull wing type semiconductor package, the data of the inspection determination reference value (in particular, the inspection determination reference value related to the lead length) is input according to various types having different package dimensions, lead widths, lead lengths, pin numbers, etc. It is necessary to use 23 and 24 to store and store in the external storage device 25. In the gull-wing type semiconductor package 1, since the lead portion is bent, when the optical axis (light flux) 8b of the optical axis (light flux) from the ring-shaped lighting device 3 hits the root of the lead tip, The light is reflected as a light flux 8b 'and enters the imaging camera 4, and the image density of that portion becomes bright. However, when the optical axis (light flux) 8a hits the bent portion of the lead, the light is reflected sideways like the light flux 8a 'and does not enter the imaging camera 4, so that when imaging with the imaging camera 4 at that portion. The image density becomes dark.

Therefore, when the image pickup camera 4 takes an image, the image pickup data of the lead portion in the semiconductor package 1 is as shown in FIG.
It becomes as shown in. That is, the imaging data captured in the image memory 6 becomes bright at the tip portion 13a and the root portion 13c of the image 12 of each of the leads 2a to 2d and becomes dark at the bent portion 13b of the lead portion. Further, as shown in FIG. 3, when the image pickup camera 4 takes an image, the distances Dt and Db from the image pickup camera 4 are different between the tip positions and the roots of the gull wing type leads 2a to 2d. On the other hand, the resolution of the image captured by the imaging camera 4 is determined by the distance from the imaging camera 4. Therefore, the lead portion looks small on the image and the resolution Pt becomes large at the tip portion having a long distance from the imaging camera 4, and the lead portion looks large on the image at the root portion having a short distance from the imaging camera 4 and the resolution Pb. Becomes smaller.

Therefore, in the present invention, after the image processing means (CPU) 7 detects the positions of the tip and the root of the lead in the image pickup data of the semiconductor package 1, the tip and the root of the lead which are obtained in advance are detected. Each lead length is calculated from the resolutions Pt, Pb and the camera center position coordinates (X0, Y0).

Next, the processing operation by the image processing means (CPU) 7 will be described with reference to the flow charts shown in FIGS. First, FIG. 3A will be described. Before starting, the type (including type) of the semiconductor package mounted on the suction head 28 is recognized, and information on the recognized type (including type) is input to the image processing device 21. Therefore, thereafter, the image processing (lead length inspection processing) is performed based on the image processing program (stored in the memory in the image processing device 21) according to the inputted type (including type) of the semiconductor package. Is done.
That is, at the time of inspection, in the image input step 41, the image pickup camera 4 images the semiconductor package 1 and A / A
The image pickup data (image data) shown in FIG. 2 converted by the D conversion unit 5 is input to the image processing device 21. Next, in the image memory storing step 42, the input image pickup data (image data) shown in FIG. 2 is stored in the image memory 6. Next, in the lead tip position detecting step 43,
The image processing means (CPU) 7 displays on the screen as shown in FIG. 2 based on the grayscale image 12 of each of the lead portions 2a to 2d obtained from the image pickup data (image data) stored in the image memory 6. Position coordinates of each lead tip (Xt1, Y
t1), (Xt4, Yt4) ... Are calculated. Next, in the lead root position detecting step 44, the image processing means (C
PU) 7 is based on the grayscale image 12 of each of the lead portions 2a to 2d obtained from the imaging data (image data) stored in the image memory 6, and as shown in FIG. Position coordinates (Xb1, Yb1), (Xb
4, Yb4) ... is calculated. Next, in step 45 of calculating the distance from the camera center to the detection point, the image processing means (CPU) 7 causes the camera center position coordinates (screen center position coordinates) (X0, Y) on the screen as shown in FIG.
0) position coordinates (X) of each lead tip calculated above.
t1, Yt1), (Xt4, Yt4) ... to length Mt1
, Mt4 ... And the position coordinates (Xb1, Yb1), (Xb) of each lead root calculated above from the camera center position coordinates (screen center position coordinates) (X0, Y0) on the screen.
4, Yb4) ... to lengths Mb1, Mb4, ... And are calculated based on the following equation (1). Mt1 = Xt1−X0, Mt4 = Xt4−X0 ... Mb1 = Xb1−X0, Mb4 = Xb4−X0 ... (Equation 1) Next, in the lead length calculation step 46. As shown in FIG. 5, the image processing means (CPU) 7 calculates the calculated lengths Mt1 to Mt16 of the tip portion and the lengths Mb1 to Mb16 of the root portion.
Then, for example, the lead lengths L1 to L16 are calculated by correction using the resolution Pt of the tip portion and the resolution Pb of the root portion stored and stored in the external storage device 25 based on the following equation (2).

L1 = Pt.multidot.Mt1 -Pb.Mb1, L4 = Pt.multidot.Mt4 -Pb.Mb4, ... (Equation 2) Thus, the lead lengths of all the leads are represented by (Equation 2).
It is not always necessary to calculate based on the formula. That is, regarding one lead represented by the side of the semiconductor package,
The lead length L1 may be calculated based on the equation (2) and used as the reference lead length. Then, the lead length L2 of the adjacent lead may be calculated from the difference .DELTA.L2 = (Mt2-Mt1) from the reference lead length L1. By doing so, the correction process based on the equation (2) can be significantly reduced. Next, in the step 47 of inspecting each lead length by comparison with the judgment reference value, the image processing means (CPU) 7, for example, the semiconductor input first from the judgment reference values stored and stored in the external storage device 25. Select the judgment reference value according to the package type (including the type), compare the judgment reference value including the selected allowable range with the calculated lead lengths L1 to L16, and confirm that the lead length is acceptable. It is determined whether or not, and the result 31 is output.

Next, FIG. 4B will be described. FIG.
4A is different from FIG. 4A in the lead length calculating step 46 in FIG. 4A, the lengths Mt1 to Mt16 of the tip end portion and the length Mb1 of the root portion calculated by the equation (2). .About.Mb16 is corrected based on the difference between the resolution Pt of the tip portion and the resolution Pb of the root portion to calculate the lead lengths L1 to L16. In FIG. The case where the determination reference value is set by correcting the length Rt of the tip portion and the length Rb of the root portion based on the difference between the resolution Pt of the tip portion and the resolution Pb of the root portion is shown. That is, step 4 in FIG.
1 to 45 are the same as the case shown in FIG. FIG.
In the inspection step 47 ′ of each lead length by comparison with the judgment reference value in (b), the image processing means (CP
U) 7 selects the judgment reference value according to the type (including the kind) of the semiconductor package input first from the judgment reference values stored and stored in the external storage device 25, as described above. , The length Rt of the tip of the selected judgment reference value
And the length Rb of the root portion, the determination reference value determined by performing correction based on the difference between the resolution Pt of the tip portion and the resolution Pb of the root portion, and the tip portion of the lead calculated in step 45. The lengths Mt1 to Mt16 and the root lengths Mb1 to Mb16 are compared in consideration of the allowable range to determine whether or not the lead length is non-defective, and the result 31 is output.

As described above, both the image processing shown in FIG. 4 (a) and the image processing shown in FIG. 4 (b) cause the resolution Pt and the root of the tip portion generated in the optical image picked up from the gull-wing type lead. The lead length is corrected including the determination reference value based on the difference from the resolution Pb of the part, so that the lead length can be accurately inspected. Next, in the calculation of the lead length L, the above two types of resolutions Pt and Pb to be used and the camera center position coordinates (X0, Y
A method of calculating 0) in advance and storing and storing it in the external storage device 25 will be described. First, the shape of the jig 61 used for the above will be described. That is, the jig 61 has a shape similar to that of the semiconductor package 1 as shown in FIG. 6, and the whole of the jig 61 is subjected to the raydent process so that the edge can be easily detected, the jig 61 is blackened, and the edge A
Was shaved and the metal portion was exposed to obtain a grayscale image signal. That is, the end of the jig 61 has a two-step structure including a surface 62 and a surface 63 whose height is matched with the surface of a gull wing type lead, and the resolution Pb from the outer edge 64 of the surface 62 depends on the height difference. Outline 63 of surface 63
From the above, the resolution Pt can be calculated by the image processing means (CPU) 7.

Next, the resolution Pt at the tip of the lead and the resolution Pb at the base of the lead are calculated in advance by using the jig 61 shown in FIG.
A method of storing and storing the data in No. 5 will be described with reference to the flowchart shown in FIG. First, the jig 61 is mounted on the suction head 28, and in the image input step 71, the image of the jig 61 is picked up by the image pickup camera 4 and the image pickup data (image data) converted by the A / D conversion means 5 is subjected to image processing. It is input to the device 21. Next, in the image memory storing step 72, the input imaging data (image data)
Are stored in the image memory 6. Next, in the jig outer edge detection step 73, the image processing means (CPU) 7
The jig 6 shown in FIG. 7B stored in the image memory 6
7B by reading out the grayscale imaging data (grayscale image data) showing the outer edge 64 of the surface 63 and the outer edge 65 of the surface 62 in FIG. 1 and applying the differential processing to obtain the difference between the digital image signals of the adjacent pixels. ) To detect (calculate) the coordinates of the outer edge indicated by x. Next, in the linear approximation step 74 by the method of least squares, the image processing means (C
PU) 7, as shown in FIG.
A straight line is extracted by performing a linear approximation by the method of least squares with respect to 4, 65. Next, in the straight line intersection calculation step 75,
The image processing means (CPU) 7 calculates the intersection coordinates of the extracted straight line. Next, in the one side length Mjt, Mjb calculation step 76, the image processing means (CPU) 7 operates as shown in FIG.
The length of one side between straight lines (distance between straight lines on the screen) Mjt, Mjb corresponding to each contour edge shown in (d) is calculated.

On the other hand, the external storage device 2 of the image processing device 21
In FIG. 5, the dimension Ljt between the outer edges 64 of the jig 61, the dimension Ljb between the outer edges 65, and the dimension Lj0 between the outer edges 64 and 65 of the jig 61 measured by using a microscope or the like are input means. It is input using 23 and 24 and is stored and stored. Therefore, the dividing ability calculation step 77
In the image processing means (CPU) 7, the length Mjt of one side between straight lines corresponding to each of the calculated outer shape edges,
Dimension Lj between Mjb and the outer edges 64 and 65 of the jig 61 stored and stored in the external storage device 25.
Based on t and Ljb, the resolutions Pt and Pb at the tip and the root of the lead are calculated from the following equation (3), and are stored and stored in the external storage device 25, for example.

Pt = Ljt / Mjt, Pb = Ljb / Mjb (Equation 3) Next, a method of previously obtaining the camera center position coordinates (X0, Y0) and storing and storing them in, for example, the external storage device 25 is shown in FIG. It will be described according to the flowchart shown in FIG. Similar to that shown in FIG. 7, first, the jig 61 is mounted on the suction head 28, and in the image input step 81, the imaging camera 4
Imaging data (image data) converted by the A / D conversion means 5 by the jig 61 is input to the image processing device 21. Next, in the image memory storing step 82,
The input imaging data (image data) is stored in the image memory 6. Next, in jig outer edge detection step 83, the image processing means (CPU) 7 causes the image memory 6 to operate.
The surface 63 of the jig 61 shown in FIG.
8B is read by reading out the grayscale image pickup data (grayscale image data) showing the outer edge 64 of the surface 62 and the outer edge 65 of the surface 62, and applying a differentiating process to obtain the difference between the digital image signals of the adjacent pixels. The coordinates of the outline edges shown are detected (calculated), and the outline edges 64 and 65 are approximated to a straight line by the method of least squares, and the coordinates Xjt and Xjb of the straight lines are calculated.
To extract. Next, in the jig tip length calculating step 84, the image processing means (CPU) 7 causes the coordinates Xjt, X of the extracted straight line on the screen as shown in FIG. 8C.
Length between jb and straight line (tip length) Mj0 = (Xjt−X
jb) is calculated (only the X-axis direction is shown). Next, in the camera center position calculation step 85, the image processing means (C
The PU) 7 stores the camera center position (X0, Y0) in the external storage device 25 and the calculated length between the straight lines (tip length) Mj0 as shown in FIG. 8D in advance. Based on the dimension Lj0 between the outer shape edge 64 and the outer shape edge 65 of the jig 61, the following formula (4) (only the X coordinate is shown. The same applies to the Y coordinate). It is calculated and stored in the external storage device 25, for example.

Lj0 = Pt (Xjt-X0) -Pb (Xjb-X0) = Pt.C-Pb. (C-Mj0) C = (Lj0-Pb.Mj0) / (Pt-Pb) X0 = Xjt-C (Formula 4) The method of calculating the two types of resolutions Pt, Pb and the camera center position coordinates (X0, Y0) in advance and storing and storing them in the external storage device 25 has been described. Since (X0, Y0) corresponds to the center position coordinates of the screen imaged by the imaging camera 4, it is clear that it may be the center position coordinates of the screen imaged by the imaging camera 4. As shown in FIG. 3, the two types of resolutions Pt and Pb have a relationship determined by the distance Dt from the imaging camera 4 to the surface of the tip of the lead and the distance Db to the surface of the root of the lead. And this distance D
Since t and Db are known values, the resolutions Pt and Pb are determined. Therefore, the determined resolutions Pt and Pb are input means 23 and 2 of the image processing device 21.
It may be input at 4 and stored and stored in the external storage device 25, for example. In addition, the distances Dt and Db are set to the image processing device 2
The image processing means (CPU) 7 calculates the two types of resolutions Pt and Pb based on the input distances Dt and Db, and inputs them to the external storage device 25, for example. It should be stored in memory.

[0024]

According to the present invention, the gull-wing type semiconductor package mounted at a predetermined inspection position is illuminated to image the leads of the semiconductor package, and the gull-wing type of each lead in each imaged row is picked up. Each lead length can be accurately measured from the lead image data, and as a result, a gull wing type semiconductor package having a desired lead length can be inspected with high reliability.

[Brief description of drawings]

FIG. 1 shows an embodiment of an appearance inspection apparatus for a gull wing type lead semiconductor package according to the present invention, FIG. 1 (a) is a diagram showing the entire structure, and FIG. 1 (b) is a plan view showing a gull wing type lead semiconductor package. It is a figure.

FIG. 2 is a diagram showing imaging data (image data) obtained by imaging a gull-wing type semiconductor package with the imaging camera shown in FIG. 1 and storing it in an image memory.

FIG. 3 is a diagram showing a positional relationship between a gull wing type lead which is an inspection object and an imaging camera.

FIG. 4 is a flowchart showing two embodiments of a method for determining and inspecting the lead length of a gull wing type lead by the image processing means (CPU) according to the present invention.

FIG. 5 shows the resolution of the tip and the root of each lead and the positional relationship between the tip and the root of each lead based on imaging data (image data) in order to calculate the lead length in the flowchart shown in FIG. It is a figure for explaining.

FIG. 6 is a diagram showing a measuring jig for acquiring in advance data required for calculating each lead length by the image processing means (CPU) according to the present invention.

FIG. 7 is a diagram showing a flowchart for calculating the resolution necessary for calculating each lead length by the image processing means (CPU) according to the present invention.

FIG. 8 is a diagram showing a flowchart for calculating a camera center position necessary for calculating each lead length by the image processing means (CPU) according to the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Semiconductor package (inspection object), 2a-2d ... Leads 3 ... Ring-shaped illumination device, 4 ... Imaging camera, 5 ... A / D
Conversion means 6 ... Image memory, 7 ... Image processing means (CPU), 21 ...
Image processing device 22 ... Display (display means), 23 ... Keyboard (input means) 24 ... Disk (input means)

Claims (12)

[Claims] 1. An illumination optical system for illuminating at least a lead portion of a semiconductor package installed at a predetermined inspection position, and capturing an optical image based on reflected light or transmitted light from at least the lead portion of the illuminated semiconductor package with an imaging optical system. Then, the image signal of the lead portion is detected, and the resolution at the tip portion of the lead and the resolution at the root portion of the lead with respect to the position coordinates of the tip portion and the root portion of the lead portion obtained from the detected image signal of the lead portion. A semiconductor device characterized in that the quality of the lead is judged by comparing with a judgment reference value based on the position coordinates of the tip and the root of the lead part after the correction. Package visual inspection method. 2. A semiconductor package installed at a predetermined inspection position is illuminated with at least a lead portion, and an optical image based on reflected light or transmitted light from at least the lead portion of the illuminated semiconductor package is picked up by an image pickup optical system. Then, the image signal of the lead portion is detected, the position coordinates of the tip and the root of the lead portion are calculated from the detected image signal of the lead portion, and the calculated position coordinates of the tip and the root of the lead are calculated. And the appearance inspection of the semiconductor package, which determines the quality of the lead by comparing the resolution at the tip of the lead portion and the determination reference value corrected based on the difference between the resolution at the root portion of the lead portion. Method. 3. The difference between the resolution at the tip of the lead and the resolution at the root of the lead changes depending on the type of the semiconductor package.
Alternatively, the semiconductor package appearance inspection method according to the item 2. 4. The method for inspecting the appearance of a semiconductor package according to claim 1, wherein the determination standard is changed according to the type of the semiconductor package. 5. The appearance inspection method for a semiconductor package according to claim 1, wherein the semiconductor package is a gull wing type. 6. The semiconductor package appearance inspection method according to claim 1, wherein the illumination light is ring-shaped illumination light. 7. An illumination optical system for illuminating at least a lead portion of a semiconductor package installed at a predetermined inspection position, and a reflected light or a transmitted light from at least the lead portion of the semiconductor package illuminated by the illumination optical system. An imaging optical system that captures an optical image to detect the image signal of the lead portion, and a lead for the position coordinates of the tip and the root of the lead portion obtained from the image signal of the lead portion detected by the imaging optical system. Correction based on the difference between the resolution at the tip of the lead and the resolution at the root of the lead, and based on the position coordinates of the tip and the root of the lead that have been corrected, compared with the determination reference value. An appearance inspection device for a semiconductor package, comprising: an image processing device for determining the quality of a lead. 8. An illumination optical system for illuminating at least a lead portion of a semiconductor package installed at a predetermined inspection position, and a reflected light or a transmitted light from at least the lead portion of the semiconductor package illuminated by the illumination optical system. An imaging optical system that captures an optical image to detect the image signal of the lead portion, and the position coordinates of the tip and the root portion of the lead portion are calculated from the image signal of the lead portion detected by the imaging optical system. The quality of the lead is judged by comparing the position coordinates of the tip and the root of the lead, and the reference value corrected based on the difference between the resolution at the tip of the lead and the resolution at the root of the lead. And an image processing device for controlling the appearance of a semiconductor package. 9. The image processing apparatus is configured to change and correct the difference between the resolution at the tip of the lead and the resolution at the root of the lead according to the type of the semiconductor package. Claim 7
Alternatively, the semiconductor package visual inspection apparatus according to the item 8. 10. The appearance inspection apparatus for a semiconductor package according to claim 7, wherein the image processing apparatus is configured to change the determination standard according to the type of the semiconductor package. 11. The semiconductor device according to claim 7, wherein the image processing apparatus is configured to select a processing program adapted to the gull-wing type from processing programs prepared according to types. Package visual inspection device. 12. The appearance inspection apparatus for a semiconductor package according to claim 7, wherein the illumination optical system is a ring-shaped illumination optical system.