JP2003232750A - Apparatus and method for visual inspection - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a visual inspection apparatus which is suitable for inspecting a semiconductor package in an in-tray state. <P>SOLUTION: An oblique light lighting unit 3 and a four-direction plane lighting unit 4 are arranged and installed in such a way that a tray pocket in a tray 9 is irradiated with beams of light from both lighting units. The lighting unit 3 illuminates a specimen from an oblique upper part tilted by e.g. 10 to 30° from a surface region on an IC to be inspected, and it can be constituted of a fluorescent tube or an LED. The lighting unit 4 is used to condense light toward the inside from four outside directions so as to reduce diffuse reflected light. As a result, it is possible to prevent e.g. a lead tip of the IC to be inspected from being reflected, and a reflected area can be reduced. The lighting units can be changed over so as to be used by corresponding to a visual inspection mode such as a lead inspection mode or a mold inspection mode. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a visual inspection apparatus for visual inspection of semiconductor packages and the like, and more particularly to a visual inspection apparatus suitable for in-tray semiconductor packages.

[0002]

2. Description of the Related Art Generally, in the visual inspection of semiconductor packages such as BGA and QFP and the visual inspection of lead frames, each item inspection is performed by image processing using projected light or transmitted light. For example, BGA (Ball Grid array)
) In the visual inspection, package dimensions, package warpage, ball position, diameter, height, etc.
In the visual inspection of the Package), mainly the EIAJ (Electronic Indus), such as the terminal flatness of the semiconductor package, the terminal width, the terminal angle, the size of each part of the lead frame, the defect inspection, etc.
Items specified by the Try Association of Japan) are inspected by image processing.

Conventionally, for example, as shown in FIG. 10, an inspector picks up an IC to be inspected from a tray and moves it to an inspection stage, and a lead floating inspection from the lateral direction is performed using a CCD line sensor. In addition, a back light is used to perform a floating test by contrast. In addition, as a simple method, an inspector visually detects the lead deformation by the light of fluorescent lamp illumination and rejects it.

[0004]

However, the IC to be inspected
There is a problem that there is a latent factor that causes defects when picking up the tray from the tray or during transportation. Further, there is a problem that the cost of the inspection device increases due to the configuration of the camera / optical system and the inspection stage for the three-dimensional inspection. On the other hand, in the visual inspection, since the inspection is performed by human eyes, there is a problem that variations and oversights occur due to individual differences.

[0005]

SUMMARY OF THE INVENTION The present invention is a visual inspection apparatus and method for solving the above problems.

That is, the appearance inspection apparatus according to the present invention includes an inspection stage on which a tray accommodating an object to be inspected is mounted, a linear actuator group for two-dimensionally controlling the position of the inspection stage, and the surface of the object to be inspected. Illuminating device, an imaging device that images the inspected object that receives illumination light from the illuminating device from above, and outputs an image including the entire surface area of the inspected object, and the imaging device that outputs the image. An image processing unit that takes in image data, analyzes the image data by a predetermined analysis program corresponding to an inspection item installed in advance, and inspects the appearance of the inspection object is characterized by being provided.

Further, in the appearance inspection apparatus of the present invention,
The inspection items are a lead inspection, a mark inspection, and a mold inspection of the inspection object.

Further, in the appearance inspection apparatus of the present invention, the image pickup apparatus is equipped with a non-angle lens.

Further, in the appearance inspection apparatus of the present invention,
The illuminating device comprises a first illuminating device and a second illuminating device, and is characterized by being switchable according to inspection items.

Further, in the appearance inspection apparatus of the present invention,
If the inspection item is a lead inspection of the inspection object, the first
It is characterized in that a four-direction surface illumination device is used as the illumination device.

Further, in the appearance inspection apparatus of the present invention, when the inspection item is the mark inspection or the mold inspection of the inspection object, the oblique illumination device is used as the second illumination device. It is a thing.

According to the present invention as described above, it is possible to perform the visual inspection of the object to be inspected with high accuracy in the in-tray state.

In the appearance inspection method of the present invention, a step of placing a tray containing an object to be inspected on an inspection stage, a step of two-dimensionally controlling the position of the inspection stage, and illuminating the surface of the object to be inspected. A step of imaging the object to be inspected that has received the illumination light from above, outputting an image including the entire surface area of the object to be inspected, and capturing the output image data and mounting it in advance. A step of analyzing the image data by a predetermined analysis program corresponding to the inspection item and inspecting the appearance of the inspected object.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the appearance inspection apparatus of the present invention will be described below with reference to the drawings. In each figure, the same parts are designated by the same reference numerals. FIG. 1 is a schematic external view of the appearance inspection apparatus of this embodiment, and FIG. 2 is a perspective view showing the main configuration thereof. The console 8 is an IC to be inspected
An inspection stage 10 is provided for placing the tray 9 accommodating the above in a predetermined position. The inspection stage 10 is supplied with electric power and can be two-dimensionally position-controlled by the Y-axis linear actuator 5 and the X-axis linear actuator 6. These linear actuators control a moving distance in a linear direction with high accuracy, and a piezoelectric actuator, a voice coil motor, a linear motor, or the like can be used. Therefore, the tray 9 on the inspection stage 10 can be positioned and controlled with high accuracy.

A tray pocket in the tray 9 is arranged so that light is emitted from the oblique light illuminating device 3 and the four-direction surface illuminating device 4. The oblique illumination device 3 illuminates an object to be inspected from an oblique upper side inclined by, for example, 10 to 30 degrees from the surface area of the IC to be inspected, and can be configured by a fluorescent tube or an LED. Further, as shown in FIG. 4, the four-direction surface lighting device 4 collects light from the four outer directions to the inner side with respect to the tray pocket, and the diffused reflected light is significantly reduced. Therefore, for example, the reflection of the tip of the lead of the IC to be inspected can be prevented, and the reflection area can be reduced as shown in FIG. These illuminating devices are configured so that they can be switched and used according to a visual inspection mode such as a lead inspection or a mold inspection.

The image pickup apparatus 1 picks up an image of the IC to be inspected irradiated with the illumination light from above and outputs an image including the entire surface area of the IC to be inspected. As the image pickup apparatus 1, for example, a digital camera having several million pixels can be adopted. A non-angle lens 2 is set in the image pickup apparatus 1. The non-angle-of-view lens 2 is a telecentric type lens, and unlike a general zoom lens as shown in FIG. 3 (1), it has almost no angle of view, so that diffused reflected light can be suppressed.

When an IC lead inspection is generally performed in the in-tray state, since the conventional general zoom lens has an angle of view of about 10 to 15 degrees, the image of the tip of the IC lead is reflected on the inner wall of the tray pocket. Easily occurs, and IC
The tip of the lead and the image of the reflection were connected, and it was sometimes detected incorrectly (Fig. 3 (1)). On the other hand, in the present embodiment, as shown in FIG. 3B, by adopting the non-viewing angle lens 2, it is possible to reduce the amount of reflection of the image of the IC lead tip, so that the IC lead tip and the reflection of the image can be reduced. The map can be accurately separated and grasped.

As described above, when the non-viewing angle lens 2 and the four-direction surface illuminating device 4 are used in combination, the reflection image on the tip of the IC lead and the reflection image on the inner wall of the tray pocket are separated even in the inspection in the in-tray state. Since this is done, it is possible to prevent erroneous detection even during image processing.

According to the appearance inspection apparatus of the present invention, it is possible to perform, for example, the lead inspection, the mark inspection, and the mold inspection of the IC to be inspected. These inspection algorithms will be described.

In the lead inspection, first, the IC to be inspected is photographed from directly above by the image pickup device 1 of the image processing apparatus. The deviation amount of the lead tip of the IC to be inspected is calculated by the two-dimensional inspection based on the captured image as shown in FIG. After that, as shown in FIG. 7, the deviation amount of the lead tip of the IC to be inspected is calculated as a floating amount by a calculation program incorporated in the image processing apparatus. At this time, the shape (length) of the leads of the IC to be inspected is not changed. The inspection of pitch and skew can be performed by a two-dimensional inspection.

Next is the case of mark inspection. The mark inspection is an inspection of a marking portion such as a company slip or a trademark attached to the IC to be inspected. As shown in FIG. 8, a mark inspection area is set, the initials of the mark are searched for in an arbitrarily defined area, and pattern matching inspection and chipping inspection are performed. The inspection standard is the same as the mark registered in advance. The chip inspection may arbitrarily determine the range to be inspected. For example, in the range of the matching rate of 50% to 80%, it can be set that the inspection of the chip is performed. Therefore, if the upper limit of the matching rate is exceeded, the determination is made only by the pattern matching inspection, and if the lower limit of the matching rate is less than the lower limit of the matching rate, it is determined as a defective product before the chipping inspection is performed.

In the case of the mold inspection, for example, using an arbitrarily set threshold value as a reference, the image data of the mold portion is subjected to gray shading processing by an arithmetic program installed in the image processing apparatus to perform the inspection. Since this gray shading process can use a known technique, its details are omitted.

As shown in FIG. 9, in the mold inspection, there are two patterns of chipping and dirt on the entire package surface of the IC to be inspected, except for some masked portions such as corners of the package and marks of ejector pins during molding. Can be inspected.

In the above-described embodiment, the inspector performs the tray remounting and the defective rejection, and the inspection process is automated. In general, providing a visual inspection apparatus with a loader / unloader mechanism leads to a significant increase in the cost of the entire apparatus. Therefore, according to the present embodiment, it is possible to suppress the cost increase in the part that is not related to the aspect of ensuring the inspection accuracy.

The present invention is not limited to the above-mentioned embodiments, and various modifications can be made within the scope of the invention described in the claims, and these are also included in the scope of the present invention. Needless to say.

[0026]

According to the present invention, the appearance can be accurately mapped in the state where the objects to be inspected are packed in the tray, that is, in the in-tray state, so that the inspection can be performed without fear of erroneous detection.

[Brief description of drawings]

FIG. 1 is a schematic external view of an appearance inspection device according to an embodiment of the present invention.

FIG. 2 is a perspective view showing the main configuration of FIG.

FIG. 3 is a comparative explanatory diagram of a conventional zoom lens and a non-angle-of-view lens of the present embodiment.

FIG. 4 is an explanatory diagram of four-direction surface illumination according to the embodiment of the present invention.

FIG. 5 is a diagram showing an example of mapping according to the embodiment of the present invention.

FIG. 6 is a diagram showing an example of an image on the image pickup apparatus according to the embodiment of the present invention.

FIG. 7 is an explanatory view of IC lead inspection according to the embodiment of the present invention.

FIG. 8 is an explanatory diagram of IC mark inspection according to the embodiment of the present invention.

FIG. 9 is an explanatory diagram of IC mold inspection according to the embodiment of the present invention.

FIG. 10 is an explanatory diagram showing an example of a conventional visual inspection.

[Explanation of symbols]

1 ... Imaging device 2 ... Angleless lens 3 ... Oblique illumination device 4 ... 4 direction surface lighting device 5 ... Y-axis linear actuator 6 ... X-axis linear actuator 7 ... Image processing unit 8 ... Console 9 ... Tray 10 ... Inspection stage

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Claims (7)

[Claims] 1. An inspection stage on which a tray containing an object to be inspected is placed, a linear actuator group for two-dimensionally controlling the position of this inspection stage, an illuminating device for illuminating the surface of the inspected object, and this illuminating device. An image of the object to be inspected that has received illumination light from above and outputs an image including the entire surface area of the object to be inspected, and image data output from the imager is captured in advance, An appearance inspection apparatus, comprising: an image processing unit that analyzes the image data and inspects the appearance of the object to be inspected by a predetermined analysis program corresponding to the installed inspection item. 2. The appearance inspection apparatus according to claim 1, wherein the inspection items are a lead inspection, a mark inspection, and a mold inspection of the inspection object. 3. The appearance inspection apparatus according to claim 1, wherein the image pickup apparatus is equipped with a non-angle lens. 4. The lighting device comprises a first lighting device and a second lighting device.
4. The appearance inspection apparatus according to claim 1, wherein the appearance inspection apparatus is configured to be switched according to the inspection item and can be used. 5. The appearance inspection apparatus according to claim 4, wherein when the inspection item is a lead inspection of the inspection object, a four-direction surface illumination device is used as the first illumination device. . 6. The appearance inspection according to claim 4, wherein when the inspection item is a mark inspection or a mold inspection of the inspection object, an oblique illumination device is used as the second illumination device. apparatus. 7. A step of placing a tray containing an inspection object on an inspection stage, a two-dimensional position control of the inspection stage, a step of illuminating the surface of the inspection object, and an illumination light. The step of taking an image of the inspected object received from above and outputting an image including the entire surface area of the inspected object, and taking in the output image data, a predetermined value corresponding to an inspection item installed in advance. And a step of inspecting the appearance of the inspected object by analyzing the image data by the analysis program.