KR20090024943A - Apparatus and method for automated optical inspection - Google Patents

Abstract

A method and apparatus are provided to rapidly inspecting whether the foreign material exists in the printed circuit board or not and to perform foreign material test of the perforated part and visual inspection of pattern at the same time. The automatic optical tester of the printed circuit board is made of the first illumination, the second illumination, and the charge coupled device and the controller(140). The transmission light is irradiated to the first illumination in the lower-part of the printed circuit board. The reflection light is irradiated to the second illumination in the upper side of the printed circuit board. The printed circuit board is the non-permeability substrate having the perforated part or the flexible substrate.

Description

Automatic optical inspection device and method {APPARATUS AND METHOD FOR AUTOMATED OPTICAL INSPECTION}

1 is a block diagram for explaining the configuration of an automatic optical inspection system according to an embodiment of the present invention.

2 is a view showing an inspection unit having a first lighting member and a second lighting member.

3A and 3B are graphs showing brightness levels (illuminance levels) obtained by illuminating reflected light and transmitted light on an impermeable substrate.

FIG. 4A is a reflection transmission image obtained by simultaneously irradiating the reflected light and the transmitted light, and FIG. 4B is a reflection image obtained by only the reflection light of a punched perforated part.

5A to 5D are graphs showing brightness levels obtained by illuminating reflected light and transmitted light to a transparent substrate.

Explanation of symbols on the main parts of the drawings

110: loader

120: inspection unit

130: unloader

140: control unit

The present invention relates to an automatic optical inspection method, and more particularly to an automatic optical inspection apparatus and method for a printed circuit board for inspecting the appearance of the inspection object.

Currently, there is a product called BOC, which is used for memory among printed wiring boards (PCB) for IC packages. The characteristic of this board is that a hole is drilled in the part where the semiconductor chip is mounted. In the recent punching process, there is a part to be cut off at the end section of the substrate, or a fibrous foreign material is left at the end, so that the semiconductor When mounting the chip, these foreign matters have hindered the mountability or the semiconductor chip surface and the substrate pattern surface have been mounted, thereby causing a fatal defect that degrades the inherent function (conductivity).

In this reality, the optical inspection industry performed the inspection by irradiating light on the substrate surface by illuminating the light between the substrate surface to be inspected and the image sensor (camera). However, even with such an illumination position (reflected illumination), even if such foreign matter is present at the perforated boundary, the perforated area is dark, and thus it is impossible to detect such foreign matter. In order to detect a defect occurring at the boundary where such a hole is formed, it is easy to recognize defects at the boundary of a hole in the image obtained through the transmitted light.

However, in order to inspect one side, image acquisition and inspection of the upper and lower lights, respectively, slow down the inspection speed, causing various problems depending on productivity and data processing speed.

The present invention provides an automatic optical inspection apparatus and method for a printed circuit board that can be quickly inspected.

An object of the present invention is to provide an automatic optical inspection apparatus and method for a printed circuit board capable of simultaneously performing foreign material inspection of the perforated portion and external appearance inspection of the pattern.

The present invention provides an automatic optical inspection apparatus and method for a printed circuit board that can easily inspect foreign matter in the solder resist (SR).

Automatic optical inspection device for a printed circuit board of the present invention for achieving the above object is a first illumination for irradiating the transmitted light to the lower surface of the printed circuit board; Second illumination for irradiating the reflected light to the upper surface of the printed circuit board; An imaging member for imaging a region of the printed circuit board on which the first and second lights are irradiated simultaneously to obtain a transmission reflection image; And a controller which receives the transmission reflection image from the image pickup member and compares the presence or absence of foreign matter with a predetermined brightness level.

In the present embodiment, the printed circuit board is an impervious substrate having perforations formed therein.

In the present embodiment, the printed circuit board is a flexible substrate having an opaque pattern formed on the transparent film.

An automatic optical inspection method of a printed circuit board for achieving the above object is irradiated transmitted light to one surface of the printed circuit board, and irradiated reflected light to the other surface of the printed circuit board to which the transmitted light is irradiated, so that the transmitted light and the reflected light The transmission reflection image obtained by imaging the area of the printed circuit board irradiated at the same time is used to inspect whether the printed circuit board is defective.

In the present embodiment, the printed circuit board is a substrate on which patterns are formed on a transparent film, and the inspection using the transmission reflection image is performed by using a brightness obtained in the pattern as a first brightness level and a brightness obtained in a space between the patterns. By binarizing to a second brightness level, it is simultaneously determined whether there is foreign matter on the pattern and in the spatial region between the patterns.

In the present embodiment, if the brightness obtained in the pattern area of the transmission reflection image is lower than the first brightness level or the brightness obtained in the spatial area of the transmission reflection image is lower than the second brightness level, it is determined that there is a foreign material. do.

In the present embodiment, the printed circuit board is any one of Tape Automated Bonding (TAB), Chip On Film (COF), and Ball Grid Array (BGA).

In the present embodiment, the printed circuit board is an impervious substrate having patterns and perforated perforations, and the inspection using the transmissive reflection image determines whether there is a foreign material on the pattern and around the perforated part. Determine whether there is any foreign object at the same time.

In the present embodiment, the printed circuit board is a board on chip (BOC).

In the present embodiment, the printed circuit board is a BOC (Board on Chip) having patterns and perforated holes, and the brightness obtained in the pattern is a brightness obtained from the pattern at a first brightness level. If the brightness obtained in the pattern area of the transmission reflection image is lower than the first brightness level or the brightness obtained in the perforated area of the transmission reflection image is lower than the second brightness level, the foreign material is binarized to a second brightness level. Determine that there is.

For example, embodiments of the present invention may be modified in various forms, and the scope of the present invention should not be construed as being limited by the embodiments described below. This embodiment is provided to more completely explain the present invention to those skilled in the art. Accordingly, the shape of the elements in the drawings and the like are exaggerated to emphasize a clearer description.

An embodiment of the present invention will be described in detail with reference to the accompanying drawings, FIGS. 1 to 5D. In addition, in the drawings, the same reference numerals are denoted together for components that perform the same function.

The inspection apparatus and method of the present invention are well suited for simultaneously inspecting the appearance (foreign material, discoloration, contamination, etc.) of an impervious substrate and inspecting defects (burrs) of perforations formed in the substrate. In addition, the inspection apparatus and method of the present invention are well suited for simultaneously inspecting foreign substances in the space between the patterns and foreign substances on the pattern formed on the transparent film.

1 is a view for explaining the configuration of an automatic optical inspection system according to an embodiment of the present invention, Figure 2 is a view showing an inspection unit having a first illumination member and a second illumination member.

1 and 2, the automatic optical inspection system 100 of the present invention is a system for automatically inspecting a test object that is a printed circuit board using reflected light and transmitted light at the same time. In the accompanying drawings, the solid arrow symbol shown in FIG. 1 indicates a moving path of the inspection object, and the dotted arrow symbol indicates signal transmission.

The optical automatic inspection system 100 includes a loader 110, an inspection unit 120, an unloader 130, and a controller 140 for controlling overall operations of these components.

The loader 110 provides an inspection object in which a printed circuit board in a film or tape form is continuously connected in a reel or roll form to the inspection unit, or provides an inspection object, which is a printed circuit board in a single form, to the inspection unit. And the unloader 130 collects the inspection object after the inspection from the inspection unit 120.

The inspection unit 120 obtains the transmission reflection image by simultaneously irradiating the reflected light and the transmitted light to the inspection object provided from the loader unit 110, and provides it to the controller 140.

The inspection unit 120 includes a first lighting member 124 for irradiating the reflected light to the upper surface of the inspection object 10, a second lighting member 126 for irradiating the transmitted light to the lower surface of the inspection object, and a first lighting member 124. And an image capturing member 122 which captures an area of a printed circuit board to which light (reflected light, transmitted light) of the second lighting member 126 is irradiated at the same time to obtain a transmission reflection image.

The controller 140 is provided with a typical computer system (aka, microcomputer) to control and process various operations according to the automatic optical inspection. In addition, the control unit 140 receives the reflection transmission image from the imager 122 to determine the defect of the inspection object. That is, the controller determines whether or not foreign matter exists by using a mutual brightness difference between the illuminance value (brightness value) of the reference image and the illuminance value of the transmission reflection image of the inspection object by a pre-programmed program.

(Imperial printed circuit board inspection)

3A and 3B are graphs showing brightness levels (amount of illuminance) obtained by illuminating reflected light and transmitted light using an impervious substrate having a perforated hole 12 as an inspection object 10a. The object 10a to be inspected here is an impermeable substrate such as a board-on-chip (BOC) having a perforated hole 12.

Referring to FIG. 3A, the inspection object 10 has patterns 13 and perforations 12 on the impermeable substrate 11. Here, the brightness obtained by the punching part 12 is binarized to the first brightness level, and the brightness obtained from the pattern is binarized to the second brightness level. For example, the first brightness level may be in the range 250L-280L (very bright), the second brightness level may be in the range 100L-130L (bright), and the brightness level of the substrate without pattern may be in the range 10-40L (dark). have.

 As shown in the graph of FIG. 3A, the brightness obtained in the pattern 13 and the brightness obtained on the substrate on which the pattern 13 is not formed are almost the same as the brightness obtained by irradiating only the reflected light because only the reflected light is affected by the transmitted and reflected light. It can be seen that. However, since the brightness of the perforated portion 12 is directly affected by the transmitted light, the brightness of the perforated portion 12 appears to be relatively brighter than the brightness obtained in another portion (pattern).

As shown in FIG. 3B, when the foreign material (burr) 12a is present in the perforated part 12, since the brightness of the part corresponding to the perforated part 12 drops rapidly below the second brightness level, the perforated part is easily provided. It is possible to easily determine whether or not there is foreign matter in (12). Of course, the foreign matter on the pattern 13 or the external inspection on the substrate (foreign material, scratch, discoloration, contamination, etc.) can be made in the same manner as the conventional inspection using only the reflected light.

For example, when the reflection image is obtained using only the reflected light, the perforated part 12 may appear dark because there is no light reflection, and even if the perforated part 12 has a foreign material 12a, the separation is not easy. However, as in the present invention, when the reflected light is obtained by using the reflected light and the transmitted light at the same time, the transmitted light does not affect other parts except the perforated part 12, and is provided only to the perforated part 12. Compared with, the light becomes relatively bright, and thus, the foreign material 12a in the perforation part 12 can be easily identified.

FIG. 4A is a reflection transmission image obtained by simultaneously irradiating the reflected light and the transmitted light, and FIG. 4B is a reflection image obtained by only the reflection light of a punched perforated part.

As shown in FIG. 4A, when looking at the reflection transmission image, the upper surface of the substrate on which the patterns are formed is affected by the reflected light, and the shapes of the patterns are not only clearly seen (parts indicated by b), but the perforated part is affected by the transmitted light. It can be seen that the protruding fibrous foreign matter can be clearly identified (indicated by a).

However, when only the reflected light is used as shown in FIG. 4B, the shapes of the patterns on the upper surface of the substrate are clearly seen, but the perforations (parts indicated by c) are almost dark enough to be difficult to read with the substrate having no pattern formed thereon. Not only is it difficult to identify study boundaries, but it is almost impossible to identify fibrous foreign bodies in perforations.

 (Transparent printed circuit board inspection)

5A to 5C are graphs showing brightness levels obtained by illuminating reflected light and transmitted light using a flexible substrate having impermeable patterns 15 on the transparent film 14 as an inspection object 10b. The object to be inspected may be any one of a tape automated bonding (TAB), a chip on film (COF), and a ball grid array (BGA) in the form of a transparent film having impermeable patterns.

Referring to FIG. 5A, the test object 10b has patterns 15 and a solder resist (SR) layer 16 on the transparent film 14. Here, the brightness obtained in the space between the patterns 15 is binarized to the first brightness level, and the brightness obtained from the pattern 15 is binarized to the second brightness level. For example, the first brightness level may be in the range of 180L-210L (very bright), and the second brightness level may be in the range of 100L-130L (bright).

As shown in the graph of FIG. 5A, since the brightness obtained in the pattern 15 is only influenced by the reflected light among the transmitted light and the reflected light, the brightness obtained by irradiating only the reflected light may be almost the same. However, the brightness of the space between the pattern 15 and the pattern 15 is relatively brighter than the second brightness obtained in the pattern 15 because the brightness of the space between the pattern 15 and the pattern 15 is simultaneously affected by the transmitted light.

As shown in FIG. 5B, when the foreign material 18 is present in the space between the pattern 15 and the pattern 15, the brightness of the portion corresponding to the space drops sharply from the first brightness level to the second brightness level. Therefore, the presence or absence of foreign matter in the space between the pattern 15 and the pattern 15 can be easily determined. If there is a foreign object in the space between the pattern and the pattern, the transmitted light is blocked by the foreign material and brightness is obtained only by the reflected light. In the case of the foreign material, the amount of reflection is considerably lower than that of the pattern (metallic pattern), in particular by the SR layer 16 The loss of light causes the brightness to drop significantly. Therefore, when there is a foreign material in the space between the pattern 15 and the pattern 15, the brightness lower than the second brightness level (for example, dark in the range of 40L-70L) appears.

As shown in FIG. 5C, when the foreign material 18 is present on the pattern 15, the brightness of the portion corresponding to the space of the pattern 15 is lower than the second brightness level, so that the presence or absence of the foreign matter on the pattern can be easily determined. .

As shown in FIG. 5D, when the SR layer 16 covering the pattern 15 is peeled off, the pattern 15 is exposed to the outside, so that the reflected light is directly irradiated and reflected to the space of the pattern 15. The brightness of the corresponding part becomes significantly higher than the first brightness level. Therefore, when the brightness corresponding to the space of the pattern 15 becomes higher than the first brightness level, it is possible to determine whether the SR layer 16 on the pattern 15 is peeled off (SR layer defect).

As described above, the present invention has a reflected transmission image obtained by simultaneously irradiating the reflected light and the transmitted light and simultaneously checks whether there is a foreign material on the pattern and in the spatial region between the patterns as compared with the illumination intensity of the predetermined reference data. There is a special effect that can simultaneously determine whether there is a foreign material on the pattern or whether there is a foreign material around the perforation.

In the above, the configuration and operation of the automatic optical inspection device and method according to the present invention have been shown according to the above description and drawings, which are merely described for example and various changes and modifications within the scope without departing from the technical spirit of the present invention. Of course this is possible.

As described above, the present invention has a reflected transmission image obtained by simultaneously irradiating the reflected light and the transmitted light and simultaneously checks whether there is a foreign material on the pattern and in the spatial region between the patterns as compared with the illumination intensity of the predetermined reference data. There is a special effect that can simultaneously determine whether there is a foreign material on the pattern or whether there is a foreign material around the perforation.

Claims (10)

In the automatic optical inspection device of a printed circuit board: First illumination for irradiating the transmitted light to the lower surface of the printed circuit board; Second illumination for irradiating the reflected light to the upper surface of the printed circuit board; An imaging member for imaging a region of the printed circuit board on which the first and second lights are irradiated simultaneously to obtain a transmission reflection image; And And a controller which receives the transmission reflection image from the image pickup member and compares the presence or absence of foreign matter with a predetermined brightness level. The method of claim 1, The printed circuit board is An automatic optical inspection device for a printed circuit board, characterized in that it is an impermeable substrate having perforated perforations. The method of claim 1, The printed circuit board is An automatic optical inspection device for a printed circuit board, characterized in that a flexible substrate having an opaque pattern formed on a transparent film. In the automatic optical inspection method of a printed circuit board: Transmitted light is irradiated to one surface of the printed circuit board, and reflected light is irradiated to the other surface of the printed circuit board to which the transmitted light is irradiated, and the transmissive reflection image obtained by capturing an area of the printed circuit board to which the transmitted light and the reflected light are irradiated simultaneously is used. Automatic optical inspection method of a printed circuit board, characterized in that for checking whether the printed circuit board is defective. The method of claim 4, wherein The printed circuit board is A substrate having patterns formed on a transparent film, Inspection using the transmission reflection image is The brightness obtained in the pattern is converted to a first brightness level, and the brightness obtained in a space between the patterns is converted to a second brightness level to simultaneously determine whether foreign matter is present on the pattern and in the spatial region between the patterns. An automatic optical inspection method for a printed circuit board, characterized in that discriminating. The method of claim 5, Characterized in that it is determined that there is a foreign material when the brightness obtained in the pattern region of the transmission reflection image is lower than the first brightness level or the brightness obtained in the spatial region of the transmission reflection image is lower than the second brightness level. Automatic optical inspection of printed circuit boards. The method according to claim 5 or 6, The printed circuit board may be any one of a tape automated bonding (TAB), a chip on film (COF), and a ball grid array (BGA). The method of claim 4, wherein The printed circuit board is An impermeable substrate having patterns and perforated perforations, Inspection using the transmission reflection image is And determining whether there is a foreign material on the pattern and whether there is a foreign material around the perforated portion at the same time. The method of claim 8, The printed circuit board is Automatic optical inspection method of a printed circuit board characterized in that the BOC (Board on Chip). The method of claim 4, wherein The printed circuit board is BOC (Board on Chip) with patterns and perforated holes, The brightness obtained in the perforated part is binarized to a first brightness level and the brightness obtained in the pattern to a second brightness level, so that the brightness obtained in the pattern region of the transmission reflection image is lower than the first brightness level or the transmission reflection. And if the brightness obtained in the perforated area of the image is lower than the second brightness level, determining that there is a foreign material.

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