JP2010210373A - Visual inspection apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a visual inspection apparatus capable of detecting a poor appearance of a silver-plated leadframe and a leadframe sealant reliably and simply, and also inspecting the leadframe and the leadframe sealant. <P>SOLUTION: The apparatus includes: a blue illuminating section for emitting blue light toward a workpiece which is disposed on a prescribed position; a photographing section which is disposed on the same side as the blue illuminating section with respect to the workpiece, and photographs an image of the workpiece; a red illuminating section which is disposed on the same side as the blue illuminating section with respect to the workpiece, and emits red light toward the workpiece; a third illuminating section which is disposed on a position facing the photographing section so as to sandwich the workpiece, and emits light toward the photographing section; and an image processing means which forms a binarized image on the basis of the image of the workpiece, and determines whether a defect is present or absent in the workpiece, on the basis of the binarized image. The image of the workpiece is photographed by the photographing section while switching operations of lighting the blue illuminating section, lighting the red illuminating section and lighting the third illuminating section. <P>COPYRIGHT: (C)2010,JPO&amp;INPIT

Description

The present invention relates to an appearance inspection apparatus used in an assembling process for assembling a semiconductor chip or the like as a package in a manufacturing process of a semiconductor device such as an IC or LSI. In particular, the present invention relates to an appearance inspection apparatus for inspecting the appearance of a lead frame sealing body formed by sealing a lead frame or a lead frame with a resin.

Conventionally, lead frames are used as components of semiconductor devices. The assembly process starts with, for example, silver plating on the tip of the inner lead of the lead frame, and includes a number of processes such as mounting of the IC chip on the island, resin sealing, cutting and separation, and formation of the external lead. ing.

The application of the semiconductor device using the lead frame is expanding, and it plays an important role such as being mounted on a control unit of a car and controlling the operation of the car. Therefore, higher and higher quality is required for these semiconductor devices.

For this reason, various quality control systems have been adopted by semiconductor manufacturers. In the assembly process, one of the quality control systems is to perform an appearance inspection of a lead frame or a semi-finished lead frame sealing body. This visual inspection is not only for the purpose of preventing the shipment of defective products, but also for the purpose of finding various visual defects that occur during the assembly process and feeding them back to the process causing the defect to improve the process. The importance is high.

Conventionally, the appearance inspection in the assembly process has been performed by visual inspection by an operator. However, many of the defects that occur in the assembly process are so small that it is difficult for humans to visually recognize, and there is a problem that skill is required for inspection. Also, with the recent miniaturization of semiconductor devices, visual inspection by workers has become increasingly difficult due to the narrowing of lead widths and spaces between leads.

Accordingly, various proposals have been made on an appearance inspection apparatus that automatically performs these appearance inspections based on images (for example, Patent Document 1 and Patent Document 2).

JP 2007-205974 A Japanese Patent No. 2922214

According to Patent Document 1, an irradiation unit that irradiates a plating surface with light having a wavelength of 600 nm or more, an imaging unit that images the plating surface irradiated by the irradiation unit, and an image data obtained by the imaging unit There has been proposed a plating inspection apparatus that includes image processing / defect determination means for determining the presence / absence of defects, and inspects lead frame plating defects.

On the other hand, lead frames, particularly lead frames with fine pitch intervals, tend to have a structure in which a Cu material is used as a material and the tip of the lead made of the Cu material is silver-plated. . However, the light beam of 600 nm or more in Patent Document 1 has substantially the same value as the reflectance from the silver-plated portion of the lead and the reflectance from the lead portion not subjected to silver plating (see FIG. 3 of Patent Document 1). It is. Therefore, it may be difficult to distinguish between a silver-plated portion and a lead portion that is not silver-plated only by contrast in an image obtained by irradiating light from the illumination means.

Therefore, according to Patent Document 1, there is a problem that it may be difficult to determine whether the defect is in the silver plating portion or in the lead portion where silver plating is not performed. Therefore, according to Patent Document 1, there is a problem that the feedback of the inspection result to the silver plating process may be insufficient. According to Patent Document 1, although the appearance inspection of the lead frame is possible, it is not certain whether the appearance inspection of the resin portion of the lead frame sealing body is possible.

On the other hand, according to Patent Document 2, a ring illumination and a TV camera are arranged above a semiconductor device, and an optimal irradiation angle parameter is obtained and stored in advance for each inspection item of the semiconductor device. For example, a device for moving the ring illumination up and down has been proposed.

However, according to Patent Document 2, since it is necessary to obtain an optimum irradiation angle parameter for each inspection item of a semiconductor device in advance, for example, many defective samples are collected and defective items of the defective samples are detected. For this reason, there is a problem that preparation before inspection may be complicated, such as the necessity of obtaining optimum parameters.
According to Patent Document 2, although the appearance inspection of the package body after resin sealing is possible, it is not certain whether the appearance inspection of the lead frame is possible.

The present invention has been made in view of the above-described conventional problems, and its object is to reliably detect the appearance defects of the lead frame and the lead frame sealing body on which the silver plating is applied and to easily detect the lead. An object of the present invention is to provide an appearance inspection apparatus that can be used for both inspection of a frame and a lead frame sealing body.

  The invention of claim 1 is an appearance inspection apparatus for inspecting the appearance of an object to be inspected comprising a lead frame subjected to silver plating and a lead frame sealing body sealed with a resin, and is arranged at a predetermined position. A blue illumination unit that emits blue light toward the object to be inspected, an imaging unit that is disposed on the same side as the blue illumination unit with respect to the object to be inspected, and that captures an image of the object to be inspected; Arranged on the same side as the blue illumination unit with respect to the inspection object, a red illumination unit that emits red light toward the inspection object, and a position facing the imaging unit across the inspection object And generating a binarized image based on the third illuminating unit that irradiates light toward the imaging unit and the image of the object to be inspected, and in the object to be inspected based on the binarized image. Image processing means for determining the presence or absence of defects, the blue Bright portion, the image pickup unit while switching the lighting of the red illumination unit and the third illumination unit is an image of the object to be inspected, a visual inspection apparatus.

According to a second aspect of the present invention, in the visual inspection apparatus according to the first aspect, the binarized image includes a first image based on reflected light obtained by reflecting the blue light by the lead frame. And

According to a third aspect of the present invention, in the visual inspection apparatus according to the first or second aspect, the binarized image is a second image based on reflected light obtained by reflecting the blue light by the lead frame sealing body. It is characterized by including.

According to a fourth aspect of the present invention, in the visual inspection apparatus according to any one of the first to third aspects, the binarized image includes reflected light obtained by reflecting the red light on the lead frame and the third illumination. And a third image based on the light from the unit.

A fifth aspect of the present invention is the visual inspection apparatus according to any one of the first to fourth aspects, further comprising: an illumination unit switching unit that switches lighting of the blue illumination unit, the red illumination unit, and the third illumination unit. It is characterized by that.

According to a sixth aspect of the present invention, in the visual inspection apparatus according to any one of the first to fifth aspects, a storage unit that stores an image of the object to be inspected, and an image capture that captures the image of the object to be inspected into the storage unit. An image capturing unit, wherein the processing of the image capturing unit and the processing of the image processing unit are performed in parallel.

A seventh aspect of the present invention is the appearance inspection apparatus according to any one of the first to sixth aspects, wherein the device under test, the blue illumination unit, the red illumination unit, the third illumination unit, and the imaging unit are substantially omitted. It is arranged on a vertical line.

According to the present invention, there is provided an appearance inspection apparatus for inspecting an appearance of an object to be inspected comprising a lead frame subjected to silver plating and a resin-encapsulated lead frame sealing body, wherein the object to be inspected disposed at a predetermined position. A blue illumination unit that emits blue light toward the inspection object, an imaging unit that is disposed on the same side as the blue illumination unit with respect to the inspection object, and that captures an image of the inspection object, and the inspection object Arranged on the same side as the blue illumination unit, a red illumination unit that emits red light toward the object to be inspected, and a position facing the imaging unit across the object to be inspected, A third illumination unit that emits light toward the imaging unit, and a binary image is generated based on the image of the object to be inspected, and whether there is a defect in the object to be inspected based on the binarized image Image processing means for determining the blue illumination unit, the front Since the imaging unit captures an image of the object to be inspected while switching the lighting of the red illumination unit and the third illumination unit, the blue illumination unit, the red illumination unit, and the third illumination unit are configured according to the inspection item. By switching the lighting of and taking an image of the object to be inspected, it is possible to reliably and easily detect the appearance defect of the lead frame and the lead frame sealing body subjected to silver plating, and to seal the lead frame and the lead frame. It is possible to provide an appearance inspection apparatus that can also be used for inspection of a stationary body.

Further, since the binarized image includes a first image based on the reflected light reflected by the lead frame, the blue light reflectivity from the silver plated portion and the silver plated Based on the contrast of the first image caused by the difference from the reflectance of the blue light from the portion where no plating is applied, it is possible to reliably detect a plating failure or the like of the silver plating portion of the lead frame.

Further, since the binarized image includes the second image based on the reflected light that is reflected by the lead frame sealing body, the second image has a defect such as a resin crack. It is possible to reliably inspect the resin portion for cracks and the like based on the contrast between the location where the occurrence of the occurrence and the normal portion of the resin portion.

Further, since the binarized image includes a third image based on the reflected light of the red light reflected by the lead frame and the light from the third illumination unit, the silver-plated portion The defects such as lead twist generated in the inner lead due to the red light and the third light passing between the leads in which the reflectance from the portion and the reflectance from the portion not plated with silver are substantially the same are ensured. The inspection object can be inspected over a larger number of items.

Moreover, since it is a structure provided with the illumination part switching means which switches lighting of the said blue illumination part, the said red illumination part, and the said 3rd illumination part, said each illumination according to an inspection item via an illumination part switching means The convenience that the lighting of the part can be switched is improved.

A storage unit that stores the image of the object to be inspected; and an image capturing unit that captures the image of the object to be inspected in the storage unit, the processing of the image capturing unit and the process of the image processing unit For example, while the image processing means is executing the process, it is possible to capture another image of the object to be inspected by the image capturing means, thereby improving inspection efficiency and inspection. Can be speeded up.

Moreover, since the said to-be-inspected object, the said blue illumination part, the said red illumination part, the said 3rd illumination part, and the said imaging part are the structures arrange | positioned on a substantially perpendicular line, the said blue illumination part, the said red illumination part, The third illumination unit and the imaging unit can be arranged in a compact manner, and the inspection apparatus can be made compact.

Hereinafter, an example of a preferred embodiment of the present invention will be described with reference to FIGS.
First, the lead frame 10 as the object to be inspected 25 will be described with reference to FIG. FIG. 1A is a plan view of the lead frame 10. FIG. 1B is an enlarged view of an arbitrary inner lead of the lead frame 10.
As shown in FIG. 1 (a), the lead frame 10 has, for example, four islands 12 arranged in a row at regular intervals in an elongated thin frame plate 11 on which IC chips (not shown) and the like are mounted. It is a so-called quadruple type that is arranged in the above. And as shown to Fig.1 (a), the inner lead 13 arrange | positioned radially around each island 12, the external lead 14 as electrodes, such as IC, the tie bar 9 for resin leak prevention, etc. are provided.

The lead frame 10 of the present embodiment is made of, for example, a copper alloy containing about 2 Wt% iron, and a silver plating 15 is applied to the tip of the inner lead 13 as shown in FIG. Hereinafter, this silver-plated area is referred to as “silver-plated area 15”. In FIG.1 (b), the code | symbol 18 has shown the raw material part made from the said copper alloy.
The lead frame is not limited to the copper alloy of this embodiment, and may be made of, for example, an iron-42 Wt% nickel alloy called 42 alloy. Further, the lead frame 10 of the present embodiment has the islands 12 arranged in a row, but the lead frame is not limited to the islands arranged in a row in this way, and the islands may be arranged in a matrix, for example. .

Next, the lead frame sealing body 20 as the inspection object 25 will be described with reference to FIG. FIG. 2A is a plan view of the lead frame sealing body 20. FIG. 2B is a front view of the lead frame sealing body 20.
As shown in FIG. 2A, the lead frame sealing body 20 of the present embodiment is formed by sealing the island 12 of the lead frame 10 described above with a resin portion 21 having a rectangular shape. . A plurality of external leads 14 appear on each side of the resin portion 21. Note that the lead frame sealing body is not limited to the quadruple type of the present embodiment, and may be, for example, an individual package (see FIG. 8) cut and separated for each resin portion 21. In FIG. 2A, the tie bar 9 described above is removed by a mold or the like.
As described above, the device under test 25 of this embodiment includes the lead frame 10 and the lead frame sealing body 20.

Next, a schematic configuration of the appearance inspection apparatus 30 according to the present embodiment will be described with reference to FIGS. 3 and 4. FIG. 3 is a schematic configuration diagram of the appearance inspection apparatus 30 of the present embodiment. FIG. 4 is a perspective view for explaining a part of the appearance inspection apparatus 30 of the present embodiment.
As shown in FIGS. 3 and 4, the appearance inspection apparatus 30 of the present embodiment includes a blue illumination unit 32, an imaging unit 34, a red illumination unit 36, a third illumination unit 38, and an image processing unit 60. The illumination unit switching means 70 and the support unit 40 that supports the device under test 25 are provided.

First, as shown in FIG. 4, the support unit 40 of the present embodiment includes, for example, two long support plates 42 and two guide plates 43 having substantially the same length as the support plate 42. Then, as shown in FIG. 4, the support portion 40 is disposed so that the plate surfaces of the guide plates 43 are opposed to each other while being separated by the width of the lead frame 10, and the support plates 42 are protruded from the opposite plate surfaces, respectively. ing. At this time, the support plates 42 are arranged to face each other while being separated by a distance of the side of the resin portion 21. Therefore, light from a third illumination unit 38 to be described later can pass between the support plates 42.
The lead frame 10 is mounted on the support plate 42 with its surface substantially horizontal, and is slidable in the longitudinal direction of the lead frame 10 while being guided by the guide plate 43.
The support unit 40 is disposed at a predetermined position, for example, between a transport unit (not shown) that transports the lead frame 10 and a storage unit (not shown) that stores the lead frame 10. Moreover, the support part 40 is provided with a belt (not shown) etc., for example, and may be comprised so that the lead frame 10 mounted on the said belt can be sent to the longitudinal direction.
In addition, the support part 40 of this embodiment can also support the lead frame sealing body 20 similarly to the lead frame 10. When the lead frame sealing body 20 is composed of the above-described individual packages, for example, a thin rectangular pallet on which a plurality of individual packages can be placed side by side is prepared, and the support unit is provided with the individual packages 29 together with the pallets. The structure which supports may be sufficient.

Next, as shown in FIG. 3 and FIG. 4, the blue illumination unit 32 includes a known ring-shaped illumination device in which a plurality of blue LEDs 33 that emit blue light 41 are arranged in a ring shape. It has a configuration capable of forming a region with uniform brightness. Here, the blue light 41 is composed of light whose wavelength is distributed in a wavelength range of 420 nm to 540 nm, for example, about 480 nm as a center.
And the blue illumination part 32 is arrange | positioned in the upper position of the support part 40 along the perpendicular line 31 which passes the support part 40, specifically about 50 mm-150 mm from the support part 40, as shown in FIG. Is done.
As described above, the blue illumination unit 32 is configured to irradiate blue light toward the device under test 25 arranged at a predetermined position, that is, the device under test 25 supported by the support unit 40.

Next, the imaging unit 34 is composed of, for example, a digital camera equipped with a CCD, and captures a grayscale image of the inspected object 25 by receiving reflected light from the inspected object 25 or the like. As shown in FIG. 3, the imaging unit 34 is disposed at an upper position of the support unit 40 along the vertical line 31, specifically, an upper position of about 200 mm to 350 mm from the support unit 40.
As described above, the imaging unit 34 is arranged on the same side as the blue illumination unit 32 with respect to the inspection target 25 and is configured to capture an image of the inspection target 25.

Next, as shown in FIG. 3, the red illumination unit 36 includes a red LED 37 that emits red light 45 and a half mirror 35, and the red light 45 emitted from the red LED 37 in a substantially horizontal direction is a half mirror. The light is reflected at 35 below. That is, the red illumination unit 36 is a coaxial epi-illumination that causes the red light 45 to enter the object vertically. As shown in FIG. 3, the red illumination unit 36 is between the support unit 40 and the imaging unit 34 along the vertical line 31, specifically, at an upper position of about 60 mm to 170 mm from the support unit 40. It is disposed immediately above the blue illumination unit 32. Therefore, the red light 45 from the red illumination unit 36 passes through the ring of the blue illumination unit 32 described above and reaches the inspection object 25, and the reflected light reflected from the inspection object 25 passes through the half mirror 35. It passes through and reaches the imaging unit 34. Here, the red light 45 is composed of light distributed in a wavelength range of about 610 nm to 710 nm with a center of about 660 nm.
As described above, the red illumination unit 36 is disposed on the same side as the blue illumination unit 32 with respect to the device under test 25 and is configured to irradiate the red light 45 toward the device under test 25.
In the present embodiment, the blue illumination unit 32 is composed of a ring-shaped illumination device, and the red illumination unit 36 is composed of coaxial epi-illumination. Conversely, the blue illumination unit is formed by coaxial epi-illumination, and the red illumination unit is The ring-shaped illumination device may be used, and the blue illumination unit may be disposed immediately above the red illumination unit. Further, the reflectance when blue light and red light are reflected on the surface of the inspection object 25 will be described later.

Next, the 3rd illumination part 38 consists of an illuminating device provided with LED (not shown) which emits a blue light or a red light, and a blue light or a red light is directly above the 3rd illumination part 38. Irradiate light. As shown in FIG. 3, the third illumination unit 38 is positioned below the support unit 40 along the vertical line 31, specifically, at a position about 80 mm below the support unit 40, and the imaging unit 34. It arrange | positions in the position facing. That is, as shown in FIG. 3, the third illumination unit 38 is disposed at a position facing the imaging unit 34 with the object 25 to be inspected, and is configured to irradiate light toward the imaging unit 34. It is.

Next, the image processing unit 60 of the present embodiment includes a storage unit 61, an image capturing unit 62, and an image processing unit 63, as shown in FIG.
The storage unit 61 is formed of a storage device such as a hard disk, for example, and is connected to the imaging unit 34, an image capturing unit 62 and an image processing unit 63, which will be described later, as shown in FIG. And the image of the to-be-inspected object 25 which the imaging part 34 imaged by the instruction | indication of the image taking-in means 62 is preserve | saved. In addition, the storage unit 61 stores a reference image that serves as a reference in pattern matching described later.

Next, the image capturing unit 62 includes, for example, a first CPU, and is connected to the imaging unit 34, the storage unit 61, an image processing unit 63 and an illumination unit switching unit 70 described later, as shown in FIG. And the process which takes in into the memory | storage part 61 the image of the to-be-inspected object 25 which the imaging part 34 imaged in response to the signal from the illumination part switching means 70 mentioned later is performed.

Next, the image processing unit 63 includes, for example, a second CPU, a working memory, and the like, and is connected to an image capturing unit 62, a storage unit 61, and an illumination unit switching unit 70 described later, as shown in FIG. The operation of the image processing means 63 configured as described above will be described later.

Next, the illumination unit switching means 70 comprises, for example, a sequencer equipped with a CPU, and as shown in FIG. 3, is connected to the red illumination unit 36, the blue illumination unit 32, and the third illumination unit 38 to switch these lighting. . The illumination unit switching unit 70 is also connected to the imaging unit 34, the image capturing unit 62, the image processing unit 63, and a conveyance unit (not shown) to perform sequence control of the entire appearance inspection apparatus 30. The operation of the illumination unit switching means 70 configured as described above will be described later.

Here, main appearance defect items of the inspection object 25 will be described with reference to the drawings.
First, the appearance defect of the lead frame 10 as the inspection object 25 will be described with reference to FIGS. 5 to 7 are views for explaining examples of appearance defects of the lead frame 10.
First, the plating failure of the inner lead 13 will be described with reference to FIG. FIG. 5A and FIG. 5B are plan explanatory views of the tip portion of the inner lead 13.
FIG. 5A shows a plating defect 16 in which a part of the tip of the inner lead 13 is not plated. FIG. 5B shows a plating leakage defect 17 plated out of a normal silver plating region (see FIG. 1B).

Next, a foreign matter adhesion failure, a twist failure, a punch failure, and a non-penetrating pinhole failure will be described with reference to FIG. 6 (a), 6 (b), 6 (d), and 6 (f) are plan explanatory views of the distal end portion of the inner lead 13. FIG. 6C is an end view taken along the line AA ′ of FIG. 6B, and FIG. 6E is an end view taken along the line BB ′ of FIG. 6D.
First, FIG. 6A shows a foreign matter adhesion failure. More specifically, reference numeral 19 denotes a foreign matter attached to the side portion of the inner lead 13, and reference numeral 23 denotes a foreign matter attached to the plate surface of the inner lead 13.
Next, FIG. 6B and FIG. 6C show a twist defect 33 in which the inner lead 13 is twisted. As shown in FIG. 6C, one side portion of the inner lead 13 is curled up.
Next, FIG. 6D and FIG. 6E show a pinch defect 24. As is apparent from FIGS. 6D and 6E, a part (24) of the inner lead 13 is thinner than other normal portions.
Next, FIG. 6F shows a non-penetrating pinhole 26 generated in the inner lead 13.

Next, the shape defect of the inner lead 13 will be described with reference to FIG.
FIG. 7A shows a lead bending failure, and reference numeral 27 denotes an inner lead in which a lead bending failure has occurred. FIG. 7B shows an example of a short-circuit failure between leads, for example, a short portion 28 occurs due to an etching failure or the like.

Next, the appearance defect of the lead frame sealing body 20 as the inspection object 25 will be described with reference to FIGS. FIG. 8 and FIG. 9 are diagrams for explaining examples of defective appearance of the lead frame sealing body 20.
8A, FIG. 8B, FIG. 8C, FIG. 9A, FIG. 9B, and FIG. 9C show the individual package 29 portion of the lead frame sealing body 20. FIG. It is a plane explanatory view.
FIG. 8A shows an example of a crack failure, and reference numeral 51 indicates a crack generated in the resin portion 21.
Next, FIG. 8B shows an example of a void defect, and reference numeral 52 indicates a void generated in the resin portion 21.
Next, FIG. 8C shows an example of gloss failure. Here, the gloss failure will be briefly described. Since the surface of the cavity of the resin-sealed mold is a so-called pear, and the surface of the resin part 21 is also a so-called pear pattern, almost no gloss is seen on the surface of the normal resin part 21 . The gloss failure is a failure in which a part of the surface of the resin portion 21 has a gloss due to, for example, a defect in the cavity. FIG. 8C illustrates a state in which the gloss portion 53 is provided on the surface of the resin portion 21.

Next, FIG. 9A shows a foreign matter adhesion failure in the external lead 14. In FIG. 9A, reference numeral 54 denotes a foreign substance.
Next, FIGS. 9 (b) and 9 (c) show a residual resin defect, FIG. 9 (b) shows a horn-like resin residue 55, and FIG. 9 (c) spans between external leads. The dam-like resin residue 56 is shown.

Next, a binarized image generated based on the image of the inspection object 25 will be described with reference to the drawings. In the present embodiment, the binarized image includes a first image, a second image, and a third image. First, the first image will be described with reference to FIGS. 10 and 11. FIG. 10 is an explanatory diagram showing the relationship between the wavelength of light and the reflectance in silver and copper. FIG. 11 is an explanatory diagram of an example of the first image.
The first image of the present embodiment is a binarized image obtained by binarizing a grayscale image captured based on the reflected light of the blue light 41 reflected by the lead frame 10 with a predetermined threshold.
As shown in FIG. 10, for light in the visible light range (wavelength range of approximately 400 nm to 700 nm), the difference between the reflectivity from silver and the reflectivity from copper is approximately 480 nm wavelength light, that is, blue light. Biggest against. Specifically, the reflectance from silver is close to 100%, and the reflectance from copper is about half that. Therefore, when the lead frame 10 is irradiated with blue light and an image of the reflected light is captured, the contrast between the silver-plated region and the copper alloy portion not subjected to silver plating is maximized in the image. Therefore, as shown in FIG. 11A, the contour shape 81 of the silver plating region appears accurately in the first image 57. For example, the defective plating defect 16 shown in FIG. 5A appears in the first image 57 as shown in FIG. Further, for example, the plating leakage defect 17 shown in FIG. 5B appears in the first image 57 as shown in FIG. In FIG. 11B, reference numeral 82 indicates an image corresponding to the defective plating defect 16. Further, in FIG. 11C, reference numeral 83 indicates an image corresponding to the plating leakage defect 17.
These defects can be reliably detected by pattern matching between the image (81) in which no defect has occurred and the first image in which the plating defect 16 or the plating leakage defect 17 has occurred.

Furthermore, according to the image captured by the inventors based on the reflected light of the blue light 41 reflected by the lead frame 10, the silver-plated region and the iron-42Wt% nickel alloy portion not subjected to silver plating It has been empirically found that the contrast of is higher than the contrast between the above-described silver-plated region and the copper alloy portion not subjected to silver plating. That is, even in a lead frame made of iron-42 Wt% nickel alloy, the blue light 41 is effective for detecting defects in the silver plating region.

Next, the second image will be described with reference to FIGS. FIG. 12 is a diagram illustrating the type of light color and contrast. FIG. 13 is an explanatory diagram of the second image, particularly an explanatory diagram of the second image related to the resin portion 21. The second image of the present embodiment is a binarized image obtained by binarizing a grayscale image captured based on the reflected light of the blue light 41 reflected by the lead frame sealing body 20 with a predetermined threshold.

In FIG. 12, the vertical axis represents the magnitude of the contrast between the normal resin portion 21 and the portion where the crack 51 or the void 52 is generated in the grayscale image by the reflected light from the lead frame sealing body 20. As shown in FIG. 12, the contrast increases as it goes up along the vertical axis. The horizontal axis indicates the type of light color. The inventors irradiated the lead frame sealing body 20 with blue light and red light by coaxial epi-illumination, and investigated the contrast in the image by the reflected light of each light. And the inventors obtained the knowledge that the said contrast by blue light is larger than red light. The reason is considered to be that the light scattering characteristics at the edges of the cracks 51 and voids 52 are different depending on the difference between the wavelength of the blue light 41 and the wavelength of the red light 45.

Therefore, the crack 51 and the void 52 appear accurately in the second image. For example, the crack 51 appears in the second image 58 as shown in FIG. Further, the void 52 appears in the second image 58 as shown in FIG. In FIG. 13A, reference numeral 51 ′ indicates an image corresponding to the crack 51. In FIG. 13B, reference numeral 52 ′ indicates an image corresponding to the void 52. In FIG. 13, reference numeral 21 ′ indicates a contour line of the resin portion 21.
Therefore, these defects can be reliably detected by the above-described pattern matching or the like.

Further, even in the case of the blue light 41, the glossy portion 53 appears brighter than the normal resin portion in the grayscale image due to the reflected light. Therefore, in the second image 58 obtained by binarizing the image with a predetermined threshold value, As shown in FIG. 13C, the glossy portion 53 can be detected. In FIG. 13C, reference numeral 53 ′ indicates an image corresponding to the glossy portion 53.

Next, the third image will be described with reference to FIG. FIG. 14 is an explanatory diagram of a third image example. Specifically, FIG. 14A shows a third image 73 corresponding to FIG. 6A, FIG. 14B shows a third image 74 corresponding to FIG. 6B, and FIG. Is a third image 75 corresponding to FIG. 6D, and FIG. 14D is a third image 76 corresponding to FIG. 6F.
In the third image of the present embodiment, an image based on the reflected light of the red light from the red illumination unit 36 reflected by the lead frame 10 and the light from the third illumination unit 38 is binary with a predetermined threshold value. This is a binarized image.

First, the third image 73 in FIG. 14A will be described as an example.
First, the light from the third illumination unit 38 reaches the imaging unit 34 between the inner leads 13, in the ring of the blue illumination unit 32, and further through a half mirror (see FIG. 3). Therefore, the imaging unit 34 can acquire a silhouette image of the lead frame 10 (see FIG. 15) only with light from the third illumination unit 38.
Next, as shown in FIG. 10, red light, for example, light having a wavelength of about 660 nm has substantially the same reflectance in silver and copper. Therefore, the brightness of the silver-plated region 15 of the inner lead 13 and the copper alloy portion 18 that is not silver-plated are substantially the same in the grayscale image resulting from the reflected light of the red light 45 reflected by the lead frame 10. Yes. However, since the red light 45 is irregularly reflected by the foreign objects 19 and 23, the foreign objects 19 and 23 appear darker than the inner lead 13 in the grayscale image. Therefore, for example, by adjusting the light quantity of the third illumination unit 38, the brightness between the inner leads 13 and the brightness of the inner leads 13 in the image are configured to be substantially the same. As a result, only the portions of the foreign matter 19 and 23 appear darker than the surroundings in the grayscale image. Therefore, by binarizing the grayscale image based on a predetermined threshold, as shown in FIG. 14A, it is possible to obtain a second image 73 in which only the portions of the foreign objects 19 and 23 are dark.

FIG. 14B shows a third image 74 obtained in the same manner as described above. In FIG. 14B, since the red light applied to the lead frame 10 is irregularly reflected on the torsionally defective 33 portion, only the torsionally defective 33 portion appears black.
Next, FIG. 14C shows a third image 75 obtained in the same manner as described above. In FIG. 14C, the red light is irregularly reflected at the portion of the poor defect 24, and only the portion of the defective defect 24 appears black.
Next, FIG. 14D is a third image 76 obtained in the same manner as described above. In FIG. 14D, the red light is irregularly reflected by the non-penetrating pinhole 26 portion, and only the non-penetrating pinhole 26 portion appears black.
As described above, according to the third image (73, 74, 75, 76), the silver plating such as the adhesion of the foreign matter (19, 23), the twisting defect 33, the chipping defect 24, the non-penetrating pinhole defect 26, etc. Even if it is a defect that can occur in either the region or the region that is not subjected to silver plating, these defects can be reliably detected. For example, in the case of the reflected light of blue light, the region not subjected to silver plating appears darker than the silver plating region 15 as described above. For this reason, when defects such as adhesion of the foreign matter (19, 23), torsional defect 33, chipping defect 24, non-penetrating pinhole defect 26, etc. occur in a region not subjected to silver plating, these defective points and silver Since the contrast with the area where plating is not performed becomes small, it becomes difficult to detect these defects.

Next, an example of a silhouette image by light from the third illumination unit 38 will be described with reference to FIGS. 15 and 16. FIG. 15 shows a silhouette image by light from the third illumination unit 38 that has passed between the leads of the lead frame 10. Specifically, FIG. 15A shows a silhouette image 84 corresponding to FIG. FIG. 15B shows a silhouette image 85 corresponding to FIG.
These defects can be detected by pattern matching between the silhouette image of the inspected object 25 in which the lead bending defect or the lead-to-lead short defect has occurred and the reference image in which no defect has occurred.

Next, FIG. 16 shows a silhouette image by light from the third illumination unit 38 that has passed between the external leads of the lead frame sealing body 20. Specifically, FIG. 16A shows a silhouette image 86 corresponding to FIG. FIG. 16B shows a silhouette image 87 corresponding to FIG. Further, FIG. 16C shows a silhouette image 88 corresponding to FIG.
The pattern matching between the silhouette image of the inspected object 25 in which the adhesion failure of these foreign matters 54, the horn-like resin residue 55, the dam-like resin residue 56, etc. has occurred, and the reference image in which no defect has occurred is performed by pattern matching. Defects can be detected.

Next, the operation of the appearance inspection apparatus 30 configured as described above will be described with reference to the drawings. FIGS. 17-19 is a flowchart explaining the example of a processing flow performed with the external appearance inspection apparatus 30 of this embodiment.

First, the operation of the illumination unit switching means 70, that is, an example of the illumination switching process flow will be described with reference to FIG.
When the object to be inspected 25 comes to a predetermined position, for example, a start signal from a transport unit (not shown) is transmitted to the illumination unit switching means 70.
The lighting unit switching means 70 that has received this start signal determines whether or not the device under test 25 is the lead frame 10 in step S10. For example, the configuration may be such that the determination is based on the presence or absence of a signal from a position sensor (not shown) made of laser light that passes a little above the support plate 42 in the horizontal direction. This is because the resin part 21 is formed in the case of the lead frame sealing body 20, and therefore it can be determined whether or not the lead frame 10 is based on whether or not the passage of the laser light is blocked by the resin part 21.
If the inspected object 25 is determined to be the lead frame 10 by the determination in step S10, the illumination unit switching unit 70 proceeds to step S12. If the determination is not made to be the lead frame 10, the process proceeds to step S34. Proceed.

Next, in step S <b> 12, the illumination unit switching unit 70 transmits a lighting signal to the third illumination unit 38 to turn on the third illumination unit 38. Then, the process proceeds to step S14.

Next, in step S <b> 14, the illumination unit switching unit 70 transmits an imaging signal instructing imaging to the imaging unit 34, and causes the imaging unit 34 to capture an image of the lead frame 10. Then, the process proceeds to step S16.

Next, in step S <b> 16, when the illumination unit switching unit 70 receives an imaging completion signal indicating that imaging has been completed from the imaging unit 34, the captured image is an image of the lead frame 10 by the light of the third illumination unit 38. Image identification information A indicating that it is a (silhouette image) and an image capture signal instructing capture of the captured image from the image capturing unit 34 are transmitted to the image capture means 62. And the illumination part switching means 70 transmits a light extinction signal to the 3rd illumination part 38 from the imaging part 34, makes the 3rd illumination part 38 light-extinguish, and advances a process to step S18 after that.

Next, in step S <b> 18, the illumination unit switching means 70 transmits a lighting signal to the blue illumination unit 32 to light the blue illumination unit 32. Then, the process proceeds to step S20.

Next, in step S <b> 20, the illumination unit switching unit 70 transmits an imaging signal to the imaging unit 34 and causes the imaging unit 34 to capture an image of the lead frame 10. Then, the process proceeds to step S22.

Next, in step S22, when the illumination unit switching means 70 receives the imaging completion signal from the imaging unit 34, the image identification information b indicating that the captured image is an image of the lead frame 10 by blue light and the image capture. The capture signal is transmitted to the image capture means 62. And the illumination part switching means 70 transmits a light extinction signal to the blue illumination part 32, makes the blue illumination part 32 light-extinguish, and then advances a process to step S24.

Next, in step S24, the illumination unit switching means 70 transmits a lighting signal to the red illumination unit 36 and the third illumination unit 38, and turns on the red illumination unit 36 and the third illumination unit 38 simultaneously. Then, the process proceeds to step S26.

Next, in step S <b> 26, the illumination unit switching unit 70 transmits an imaging signal to the imaging unit 34 and causes the imaging unit 34 to capture an image of the lead frame 10. Then, the process proceeds to step S28.

Next, when the illumination unit switching unit 70 receives the imaging completion signal from the imaging unit 34 in step S28, the captured image is red light and an image indicating that the lead frame 10 is an image of the third illumination unit 38. The identification information C and the image capture signal are transmitted to the image capture means 62. And the illumination part switching means 70 transmits a light extinction signal to the red illumination part 36 and the 3rd illumination part 38, makes the red illumination part 36 and the 3rd illumination part 38 light-extinguish, and then advances a process to step S30.

Next, in step S30, the illumination unit switching means 70 transmits an instruction to send the lead frame 10 to the transport unit, and the lead frame so that the center vicinity of the adjacent island 12 is directly below the imaging unit 34 via the transport unit. Send ten. Then, the process proceeds to step S32.

Next, in step S32, the illumination unit switching unit 70 determines whether or not the imaging of one lead frame 10 has been completed (for example, whether or not imaging for four islands has been completed), and has not ended. If it is determined, the process proceeds to step S12. If it is determined that the process has been completed, the process ends.

Next, in step S <b> 34, the illumination unit switching unit 70 transmits a lighting signal to the third illumination unit 38 to turn on the third illumination unit 38. Then, the process proceeds to step S36.

Next, in step S <b> 36, the illumination unit switching unit 70 transmits an imaging signal to the imaging unit 34 and causes the imaging unit 34 to capture an image of the lead frame sealing body 20. Then, the process proceeds to step S38.

Next, in step S38, when the illumination unit switching unit 70 receives the imaging completion signal from the imaging unit 34, the captured image is an image (silhouette image) of the lead frame sealed body 20 by the light of the third illumination unit 38. The image identification information D indicating that the image is received and the image capture signal are transmitted to the image capture means 62. And the illumination part switching means 70 transmits a light extinction signal to the 3rd illumination part 38, makes the 3rd illumination part 38 light-extinguish, and advances a process to step S40 after that.

Next, in step S <b> 40, the illumination unit switching unit 70 transmits a lighting signal to the blue illumination unit 32 to light the blue illumination unit 32. Then, the process proceeds to step S42.

Next, in step S <b> 42, the illumination unit switching unit 70 transmits an imaging signal to the imaging unit 34 and causes the imaging unit 34 to capture an image of the lead frame sealing body 20. Then, the process proceeds to step S44.

Next, in step S44, when the illumination unit switching means 70 receives the imaging completion signal from the imaging unit 34, the image identification information h and the image identification information indicating that the captured image is an image of the lead frame sealing body 20 by blue light. The image capture signal is transmitted to the image capture means 62. And the illumination part switching means 70 transmits a light extinction signal to the blue illumination part 32, turns off the blue illumination part 32, and advances a process to step S46 after that.

Next, in step S46, the illumination unit switching means 70 transmits an instruction to feed the lead frame 10 to the transport unit, and leads through the transport unit so that the vicinity of the center of the adjacent resin unit 21 is directly below the imaging unit 34. Send frame 10. Then, the process proceeds to step S48.

Next, in step S48, the illumination unit switching unit 70 determines whether or not the imaging of the lead frame sealing body 20 has been completed (for example, whether or not imaging of four packages has been completed), and ends. If it is determined that the process has not been completed, the process proceeds to step S34. If it is determined that the process has been completed, the process ends.

As described above, the appearance inspection apparatus 30 according to the present embodiment is configured to include the illumination unit switching means 70 that switches the lighting of the blue illumination unit 32, the red illumination unit 36, and the third illumination unit 38.

Next, an example of an image capture processing flow will be described with reference to FIG.
As described above, the first CPU (image capture means 62) that has received the image identification information (I, B, C, D, E) and the image capture signal from the illumination unit switching means 70 captures an image in step S50. The captured image of the unit 34 is read out, and the image identification information (I, B, C, D, E) is attached to the captured image and stored in a predetermined area of the storage unit 61. Then, the image capturing means 62 transmits an image processing signal that instructs the image processing means 63 to start image processing, and ends the processing.
Thus, the first CPU functions as the image capturing means 62 that captures the image of the inspection object 25 in the storage unit 61.

Next, the operation of the image processing means 63, that is, an example of the image processing flow will be described with reference to FIG.
The second CPU (image processing means 63) that has received the image processing signal described above reads the image identification information and the captured image from the predetermined area of the storage unit 61 in step S52, and advances the processing to step S54.

Next, in step S54, the second CPU determines whether or not the read image identification information is image identification information i. If not, the process proceeds to step S56. If it is determined that the image identification information is a, the process proceeds to step S64.

Next, in step S56, the second CPU determines whether or not the image identification information is image identification information b. If not, the process proceeds to step S58, where image identification information b is determined. If it is determined that the information is low, the process proceeds to step S66.

Next, in step S58, the second CPU determines whether or not the image identification information is image identification information c. If it is not determined to be image identification information c, the process proceeds to step S60, and the image identification information is determined. If it is determined that the information is c, the process proceeds to step S70.

Next, in step S60, the second CPU determines whether or not the image identification information is image identification information d. If not, the process proceeds to step S62, and the image identification information is determined. If it is determined that the information is c, the process proceeds to step S74.

Next, in step S62, the second CPU determines whether or not the image identification information is image identification information e. If it is determined, the process proceeds to step S76.

Next, in step S64, the second CPU associates the reference image previously stored in the storage unit 61 with the image identification information A, for example, the image of the lead frame 10 having no defect, and the imaging read in step S52. For example, pattern matching with an image (a silhouette image of the lead frame 10 (see FIG. 15)) is executed. Then, the presence or absence of a defect in the lead frame 10 is determined, and the result is stored in the storage unit 61. Thereafter, the process ends.

Next, in step S66, the second CPU generates a first image 57 obtained by binarizing the captured image read out in step S52 (the grayscale image of the lead frame 10 using blue light) with a predetermined threshold. . Then, the process proceeds to step S68.

Next, in step S68, the second CPU associates the reference image previously stored in the storage unit 61 with the image identification information b, for example, the image of the silver-plated region 15 having no defect, and the first image. Pattern matching with 57 is executed. Then, the presence or absence of a defect in the silver plating region 15 is determined, and the result is stored in the storage unit 61. Thereafter, the process ends.

Next, in step S70, the second CPU binarizes the captured image read out in step S52 (red light and grayscale image of the lead frame 10 by the third illumination unit 38) with a predetermined threshold value. Images 73, 74, 75, and 76 are generated. Then, the process proceeds to step S72.

Next, in step S72, the second CPU stores a reference image stored in the storage unit 61 in advance in association with the image identification information C, for example, an image including only a white background, the third image 73, Pattern matching with 74, 75, 76 is executed. Then, the presence or absence of a defect in the inner lead 13 is determined, and the result is stored in the storage unit 61. Thereafter, the process ends.

Next, in step S74, the second CPU correlates with the reference image previously stored in the storage unit 61 in association with the image identification information D, for example, an image of the lead frame sealing body 20 having no defect, and in step S52. Pattern matching with the read captured image, that is, the image of the lead frame sealing body 20 by the light of the third illumination unit 38 (see FIG. 16) is executed. Then, it is determined whether there is a defect in the external lead 14 and the result is stored in the storage unit 61. Thereafter, the process ends.
Note that the determination in step S74 is not limited to pattern matching. For example, a search line parallel to the longitudinal direction of the external lead 14 is set at a position close to the external lead, and light and darkness on the search line is detected. There may be.

Next, in step S76, the second CPU binarizes the image read in step S52 (the grayscale image of the lead frame sealing body 20 with blue light) with a predetermined threshold value 58, 59. , 71 (see FIG. 13). Then, the process proceeds to step S68.

Next, in step S78, a reference image previously stored in the storage unit 61 in association with the image identification information e, for example, an image of the resin part 21 having no defect, and the second images 58, 59, 71 are stored. Perform pattern matching. And the presence or absence of the defect in the resin part 21 is determined, and the result is stored in the storage part 61. Thereafter, the process ends.

As described above, according to the appearance inspection apparatus 30 of the present embodiment, the binarized image (first image, second image, third image) is generated based on the image of the inspection object 25 and 2 An image processing means 63 for determining the presence or absence of a defect in the inspection object 25 based on the digitized image is provided, and the imaging unit 34 is switched while switching the lighting of the blue illumination unit 32, the red illumination unit 36, and the third illumination unit 38. The configuration is such that an image of the inspection object 25 is captured.
Further, according to the appearance inspection apparatus 30 of the present embodiment, the processing of the image capturing means 62 and the processing of the image processing means 63 are configured to be performed in parallel.

According to the embodiments described so far, it is possible to reliably and easily detect the appearance defects of the lead frame 10 and the lead frame sealing body 20 that have been subjected to silver plating, and also to detect the lead frame 10 and the lead frame sealing body 20. It is possible to provide an appearance inspection apparatus 30 that can be used for both inspections.

As described above, some of the embodiments of the present invention have been described in detail with reference to the drawings. However, these are merely examples, and the present invention is variously modified and improved based on the knowledge of those skilled in the art. Can be implemented. For example, the second CPU as the image processing unit 63 may be charged with the function as the image capturing unit.

It is explanatory drawing of the to-be-inspected object of this embodiment. It is explanatory drawing of the to-be-inspected object of this embodiment. It is a schematic block diagram of the external appearance inspection apparatus of this embodiment. It is a perspective view explaining a part of appearance inspection device of this embodiment. It is explanatory drawing of the example of the plating defect in the inner lead of a to-be-inspected object. It is explanatory drawing of the defect which generate | occur | produced in the inner lead of to-be-inspected object. It is explanatory drawing of the defect which generate | occur | produced in the inner lead of to-be-inspected object. It is explanatory drawing of the defect which generate | occur | produced in the resin part of to-be-inspected object. It is explanatory drawing of the defect which generate | occur | produced in the external lead of the to-be-inspected object. It is explanatory drawing which shows the relationship between the wavelength of the light in silver and copper, and a reflectance. It is explanatory drawing of the 1st image in this embodiment. It is a figure explaining the contrast in the image of a resin part. It is explanatory drawing of the 2nd image in this embodiment. It is explanatory drawing of the 3rd image in this embodiment. It is explanatory drawing of the silhouette image in this embodiment. It is explanatory drawing of the silhouette image in this embodiment. It is a flowchart explaining the example of a processing flow performed with the external appearance inspection apparatus of this embodiment. It is a flowchart explaining the example of a processing flow performed with the external appearance inspection apparatus of this embodiment. It is a flowchart explaining the example of a processing flow performed with the external appearance inspection apparatus of this embodiment.

DESCRIPTION OF SYMBOLS 10 Lead frame 15 Silver plating area | region 20 Lead frame sealing body 30 Appearance inspection apparatus 32 Blue illumination part 34 Imaging part 36 Red illumination part 38 3rd illumination part 41 Blue light 45 Red light 61 Memory | storage part 62 Image capture means 63 Image processing means 70 Illumination section switching means 57, 82, 83 First image 58, 59, 71 Second image 73, 74, 75, 76 Third image

Claims (7)

An appearance inspection apparatus for inspecting the appearance of an object to be inspected comprising a lead frame subjected to silver plating and a lead frame sealing body sealed with resin,
A blue illumination unit that emits blue light toward the object to be inspected arranged at a predetermined position;
An imaging unit that is disposed on the same side as the blue illumination unit with respect to the object to be inspected, and that captures an image of the object to be inspected;
A red illumination unit disposed on the same side as the blue illumination unit with respect to the object to be inspected, and irradiating red light toward the object to be inspected;
A third illumination unit that is disposed at a position facing the imaging unit across the object to be inspected, and irradiates light toward the imaging unit;
An image processing unit that generates a binarized image based on the image of the object to be inspected, and that determines whether there is a defect in the object to be inspected based on the binarized image;
An appearance inspection apparatus, wherein the imaging unit captures an image of the object to be inspected while switching lighting of the blue illumination unit, the red illumination unit, and the third illumination unit. The visual inspection apparatus according to claim 1, wherein the binarized image includes a first image based on reflected light obtained by reflecting the blue light by the lead frame. The visual inspection apparatus according to claim 1, wherein the binarized image includes a second image based on reflected light obtained by reflecting the blue light by the lead frame sealing body. 4. The binarized image includes a third image based on reflected light obtained by reflecting the red light by the lead frame and light from the third illumination unit. The visual inspection apparatus according to any one of the above. The appearance inspection apparatus according to claim 1, further comprising an illumination unit switching unit that switches lighting of the blue illumination unit, the red illumination unit, and the third illumination unit. A storage unit that stores an image of the object to be inspected; and an image capturing unit that captures the image of the object to be inspected in the storage unit, and the processing of the image capturing unit and the processing of the image processing unit are performed in parallel. The visual inspection apparatus according to claim 1, wherein the visual inspection apparatus is performed. The appearance according to claim 1, wherein the object to be inspected, the blue illumination unit, the red illumination unit, the third illumination unit, and the imaging unit are arranged on a substantially vertical line. Inspection device.

Images