JPH03210410A - Pin grid array inspecting instrument - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Summary] A pin grid array inspection device, particularly for inspecting the presence or absence of defects by observing the shape of board connection pins provided in an array on the back side of a package such as an IC or LSI. Regarding the technology, the purpose is to observe the entire circumferential shape of each pin, which is difficult to observe on the back side of the package, and to easily inspect the presence or absence of defects. an optical system that irradiates the pin from two directions orthogonal to the pin; and an optical system that is provided downstream of the pin to be inspected in the direction of irradiation of the light, and forms an image of the pin to be inspected at each focal position. A pair of image detection optical systems cut out four images of only the periphery of the inspection target pin from the images detected by the pair of image detection optical systems, and the images are arranged so that the images from successive positions are adjacent to each other. and an image synthesizing means for rearranging the images, and is configured to inspect each pin for the presence or absence of defects based on the result of the image synthesis.

[Industrial application field]

The present invention relates to a pin grid array inspection device, and particularly,
The present invention relates to a technique for inspecting the presence or absence of defects by observing the shape of board connection pins provided in an array on the back side of a package such as an IC or LSI.

As LSIs become more highly integrated, increasing the density of their packages on printed circuit boards has also become an issue.

The mounting technology was the original DIP (Dual In-1).
ine Package) to Q F P (Quad
There is a trend toward higher density of lead lines and an increase in the number of pins, such as in FlatPackage. These technologies attempt to pull out the pins along the edge of the package, but recently, methods that utilize the surface of the package to pull out the pins in a grid pattern, such as a pin grid array (see Figure 6), have been developed. ) and a method using bumps have been proposed.

The present invention attempts to inspect the joints of each pin from the outside to check for defects, such as solder wetting as shown in FIGS. There are defective defects, protrusion defects as shown in FIG. 2(d), and the like.

Note that FIG. 7(a) shows the shape of a normal pin.

[Prior art and problems to be solved by the invention] Conventionally, in order to inspect the soldering part (the tip of each pin),
The shape of the solder is inspected by observing its appearance with a stereomicroscope, or the amount of solder is determined from the density of the gradation image by observing an X-ray transmission image.

However, the visual inspection only targets those that can be directly observed from the outside, and it is not possible to inspect pins located on the back side of the package, especially those located deep from the periphery. On the other hand, X-ray inspection has the advantage of being able to observe the shape of soldered parts, which cannot be directly observed from the outside, in the form of an image. , IC, LSI, etc. are observed overlapping each other, so it is necessary to separate them. This is not desirable because it leads to complicated image processing.

Therefore, the only way to inspect the appearance of the pin grid array provided on the back side of the package is to observe it from above or to observe the reflected image using a mirror.

However, with this method, only a part of the surface of each pin can be observed, making it difficult to easily inspect the presence or absence of defects.

The present invention was created in view of the problems in the prior art, and is a pin grid that can observe the entire circumferential shape of each pin, which is difficult to observe on the back side of a package, and can easily inspect the presence or absence of defects. The purpose is to provide an array inspection device.

[Means to solve the problem]

In order to solve the above problems, the present invention includes an orthogonal illumination optical system and an image processing system that reorganizes the obtained image in order to observe the shape over the entire circumference of each pin of the pin grid array.

That is, according to the present invention, there is provided an apparatus for inspecting the presence or absence of defects by observing the shape of board connection pins provided in an array on the back side of an integrated circuit package, the apparatus for inspecting the presence or absence of defects therein. an optical system that emits light from two directions perpendicular to the pin to be inspected along the back surface of the pin; A pair of image detection optical systems form an image at the focal position, and from the images detected by the pair of image detection optical systems, four images of only the periphery of the inspection target pin are cut out, and images from consecutive positions are cut out. A pin grid array inspection device comprising an image composition means for rearranging images so that the images are adjacent to each other, and inspecting the presence or absence of defects in each pin based on the result of the image composition. provided.

[Effect]

According to the above-mentioned configuration, the image compositing means rearranges (image compositing) the four images around the pin to be inspected so that they are continuous, so the image of the entire periphery of the pin is easily visible. can be expressed. This makes it possible to easily inspect whether or not the pin has a defect.

Note that other structural features and details of the operation of the present invention will be explained using the embodiments described below with reference to the accompanying drawings.

〔Example〕

FIG. 1 schematically shows a part of the configuration of a pin grid array inspection apparatus as an embodiment of the present invention.

In the figure, 1 is an IC package, Pi is an array of pins (pin grid array) provided on the back side of the package, Li is solder attached to the tips of the corresponding pins, and 2 is a pin grid array. Intermediate.

A printed circuit board on which the technology cage 1 is mounted, 11 is a light source (for example, a halogen lamp), 12a and 12b are optical fibers for guiding the light from the light source, and 13a and i3b are for guiding the light emitted from the optical fibers 12a and 12b, respectively. A triangular mirror that reflects light in a predetermined direction is shown. triangular mirror 1
3a and 13b are each moved to an appropriate position by a drive system (not shown) before each pin is inspected.

In this case, as shown in FIG. 2(a), the lights La and Lb reflected by the triangular mirrors 13a and 13b are arranged along the back surface of the package l so that they are respectively orthogonal to the pin to be inspected Po. The position of the triangular mirror is adjusted. At this time, the directions of the light emitting ends of the optical fibers 12a and 12b are also adjusted as appropriate.

14 are reflected lights La and L from the triangular mirrors 13a and 13b.
The triangular mirrors 15a and 15b reflect the triangular mirror 14, and objective lenses 15a and 15b are arranged to receive the light reflected by the triangular mirror 14 (corresponding to the reflected lights La and Lb, respectively).
Reference numerals 6a and 16b indicate CCDs (charge coupled devices) placed at the focal positions of objective lenses 15a and 15b, respectively.

Objective lens 15a (15b) and CCD 16a (16
b) An image detector Da (Db) is constructed from D.

In the case of the irradiation mode shown in FIG. 2, as shown in FIG. 2(b), the image detector Da detects only the images of the portions ■ and ■ among the images around the pin Po to be inspected. on the other hand,
The image detector Ob detects only the images of the parts marked ■ and ■. FIGS. 3(a) and 3(b) schematically show images detected by image detectors Da and Db, respectively.
In the figure, the hatched portions correspond to the pins.

Returning to FIG. 1, 17 indicates an image synthesizer, which cuts out four images ■ to ■ of only the surrounding area of the pin to be inspected Pa based on the image data detected by the image detectors Da and Db.
It has a function to perform image synthesis so that images from consecutive positions are adjacent to each other. An example of image synthesis is shown in Fig. 4. Regarding the images obtained by the 0-image detectors Da and Db (see Fig. 3 (a) and (b)), the central part of the pin is the same as the previous pin in the same row. The disadvantage is that sufficient observations cannot be made because it is in the shadow of the Therefore, in order to make the pin images easier to see, the image synthesizer 17 cuts out and rearranges the images (1) to (2).

18 is an image output device (
For example, a CRT), 19 is a drive mechanism for moving the objective lenses 15a and 15b of the image detectors Da and Db in the optical axis direction and a direction perpendicular thereto so that the objective lenses 15a and 15b can observe the same pin, and 20 indicates a controller. The controller 20 controls the image synthesizer 17 to cut out and rearrange images, the image output device 18 controls the output of observed images, and the drive mechanism 19 controls the objective lens 15a. , 15b has a function of controlling the position adjustment.

Next, a method for inspecting a pin grid array will be explained.

First, the light from the light source 11 is connected to the optical fibers 12a and 12b.
through the triangular mirrors 13a and 13b, respectively.

The reflected lights La and Lb from the triangular mirrors 13a and 13b are irradiated to the pin to be inspected PO so as to be orthogonal to each other, as shown in FIG. 2(a). The light that has passed around the pin enters the triangular mirror 14, is reflected by the triangular mirror, is further focused by the objective lenses 15a and 15b of the image detectors Da and Db, and is focused on the respective CCDs 16a.
, 16b. The images detected by the image detectors Da and Db look like those shown in FIGS. 3(a) and 3(b), so the next-stage image synthesizer 17 cuts out an image of only the surrounding area of the pin, and By rearranging the images so that images from consecutive positions are adjacent to each other (see FIG. 4), the shape of the entire periphery of the pin can be expressed in an easy-to-see image.

This makes it possible to easily inspect whether or not the pin has a defect.

FIG. 5 shows a flowchart of the pin grid array inspection process performed by the apparatus shown in FIG.

First, in step S1, a table (not shown) on which the printed circuit board 2 with the package l mounted thereon and the triangular mirrors 13a, 13b, and 14 are connected to a drive system (not shown).
It is moved and adjusted to an appropriate position. In step S2, by appropriately adjusting the directions of the light emitting ends of the optical fibers 12a and 12b, light is irradiated so that the two incident lights are perpendicular to the pin Po to be inspected, as shown in FIG. 2(a). The direction is adjusted. In step s3, the drive mechanism 19 drives the objective lenses 15a and 15 of each image detector Da and Db.
b position adjustment and focusing are performed.

In step S4, the CCD1 of each image detector Da, Db
6a and 16b detect the image of the pin Po to be inspected (see FIGS. 3(a) and 3(b)). Step S5
Then, the image synthesizer 17 cuts out and rearranges the images (see FIG. 4), and in step s6, the image output device 18 observes the synthesized image, thereby determining whether or not there is a defect in the pin Po. be inspected.

Finally, in step S7, it is determined whether the inspection has been completed for all pins (Yll!S) or not (NO). If the determination is YES, this flow is "end", and if the determination power < NO Then, the process returns to step S1 and the above-described process is repeated.

〔Effect of the invention〕

As described above, according to the present invention, the entire circumferential shape of each pin, which is difficult to observe on the back side of the package, can be expressed in an easy-to-see image, and the presence or absence of defects can be easily inspected.

[Brief explanation of drawings]

FIG. 1 is a block diagram partially schematically showing the configuration of a pin grid array inspection device as an embodiment of the present invention, and FIGS. 2(a) and (b) are inspections using the illumination optical system of FIG. 1. 3(a) and 3(b) are diagrams schematically showing images detected by a pair of image detectors in FIG. 2; Fig. 4 is a diagram for explaining the operation of the image synthesizer in Fig. 1, Fig. 5 is a flowchart showing the pin grid array inspection process performed by the apparatus shown in Fig. 1, and Fig. 6 is for explaining the pin grid array. FIGS. 7(a) to 7(d) are sectional views showing the shape of each pin when the pin grid array is mounted on a substrate. (Explanation of symbols) Pi, Po...pin, 1...(IC) package,
2... Printed circuit board, 11... Light source, 12a, 12
b... Optical fiber, 13a, 13b, 14... Triangular mirror, 15a, 15b - Objective lens, 16a, 16
b-CCD, 17. Image synthesizer, 18. Image output device, 19. Drive mechanism, 20. Controller, Da, Db. Image detector.

Claims (1)

[Claims] A device for inspecting the presence or absence of defects by observing the shape of substrate connection pins (Pi) provided in an array on the back side of an integrated circuit package (1), comprising: a light source (11); ) from two directions perpendicular to the pin to be inspected (Po) along the back surface of the package; A pair of image detection optical systems (Da, Db
), cutting out four images of only the peripheral area of the pin to be inspected from the images detected by the pair of image detection optical systems, and rearranging the images so that the images from consecutive positions are adjacent to each other. 1. A pin grid array inspection device comprising: image synthesis means (17, 20), and inspects each pin for the presence or absence of defects based on the result of the image synthesis.