KR100737758B1 - Automated optical inspection system including lighting device and method for inspecting of the same - Google Patents

Abstract

The present invention relates to a lighting device having first and second light sources, an optical inspection system having the same, and a method for inspecting a pattern of a printed circuit board thereof. The illumination device provided in the automatic optical inspection system of the present invention includes at least one first light source for outputting reflected light centering on a planar portion of the printed circuit board pattern, and receiving the reflected light from the first light source and outputting the reflected light to the in-circuit circuit board. A beam splitter that receives the light reflected from the printed circuit board and outputs the reflected light to the image sensor, at least one second light source that outputs the reflected light around the edge portion of the printed circuit board pattern, and receives and collects the reflected light from the second light source The light condensing lens is provided to improve brightness and uniformity of light when an image of a fine pattern of a printed circuit board is acquired. Therefore, according to the present invention, by using the first and second light sources to obtain the image data of the planar portion and the edge portion of the printed circuit board pattern by inspecting the pattern, accurate inspection is possible, thereby undetected and overdetected Can be prevented. In addition, by providing the lighting device as a modular module for two types of substrates having different surface characteristics, optical inspection can be applied without replacing the lighting device.

Automatic optical inspection system (AOI), lighting device, light source, fine pattern, brightness uniformity

Description

AUTOMATIC OPTICAL INSPECTION SYSTEM INCLUDING LIGHTING DEVICE AND METHOD FOR INSPECTING OF THE SAME}

1 is a perspective view showing the configuration of a lighting apparatus according to the present invention;

FIG. 2 is a cross-sectional view showing the configuration of an automatic optical inspection system having the illumination device shown in FIG.

3 shows a pattern of a printed circuit board according to an embodiment of the present invention;

FIG. 4 is a view illustrating comparison of brightness and uniformity of brightness according to the measurement position of the pattern illustrated in FIG. 3; FIG. And

Fig. 5 is a flowchart showing the inspection procedure of the optical inspection system provided with the lighting device of the present invention.

Explanation of symbols on the main parts of the drawings

100: automatic optical inspection system 102: image sensor

104: printed circuit board pattern 110: lighting device

112: first light source 114: beam splitter

116: second light source 118: condensing lens

120: image processing device 130: measurement position

The present invention relates to an automatic optical inspection system, and more particularly, to a lighting device having a plurality of light sources, an automatic optical inspection system having the same, and a method for inspecting an ultrafine pattern of a printed circuit board thereof.

In recent years, printed circuit boards, which are one of the main materials used in various semiconductor integrated circuits such as LCD driver ICs, memory and LSIs, and micro products, have been manufactured in the form of films and tapes. .

Among these printed circuit boards, a circuit commonly referred to as a tape automatic bonding (TAB) or a chip on film (COF) substrate is used. Printed circuit boards in the form of films and tapes are patterned through manufacturing processes such as exposure, development, and etching. These patterns are extremely miniaturized as semiconductor devices become increasingly miniaturized, making it difficult to inspect pattern defects through the neck. The situation is getting worse. Therefore, accurately detecting defects in the pattern of the printed circuit board is an important factor in improving the productivity of the semiconductor device.

For this reason, the demand of the optical automatic inspection system of printed circuit boards is increasing, and the automatic automatic inspection system has problems of undetected phenomena of pattern defects and overdetection of detecting good products as defects in appearance inspection of printed circuit boards. There is this. This problem is one of the important factors that have an absolute influence on the reliability of the optical automatic inspection system.

A general optical automatic inspection system performs an optical inspection by using a camera, an image sensor, and the like. At this time, the optical automatic inspection system performs an accurate inspection of the appearance of the printed circuit board using a lighting device, for example, a transmission light and / or a reflection light, and the selection of any one of the various lighting devices is performed. It is essential for accurate fault detection.

For example, in inspecting a COF substrate in a film or tape type substrate, the COF substrate has a very reflective surface because its surface is similar to a mirror. The light is transmitted to the image sensor only when the angle of incidence of the light shining on the inspection object of the COF substrate is irradiated perpendicularly to the image sensor.

For this reason, the pattern on the substrate becomes smaller and at the same time, in the shape of the pattern, the upper surface of the pattern, that is, the planar portion, and both end surfaces of the pattern, that is, the edge portion, is changed in technical aspect, so that the printed circuit board is subjected to the same lighting conditions. The problem is caused by checking. That is, when one illumination device is used, both ends of the pattern are not reflected exactly vertically to the image sensor differently from the upper surface of the pattern, and thus accurate optical inspection is difficult because accurate image data is not obtained at both ends. This phenomenon affects product yield because it causes undetection and overdetection of fatal defective items caused by problems such as image distortion that occurs frequently as the pattern on the printed circuit board in the form of film or tape is extremely fine. Will cause.

An object of the present invention is to solve the above-described problems, to prevent the undetected and overdetected phenomena of fatal defective items caused by the image distortion caused by the pattern on the printed circuit board in the form of film, tape To implement an automatic optical inspection system and an inspection method thereof.

Another object of the present invention is to solve the above-described problems, to overcome the limitations of brightness due to the shape and characteristics on the pattern surface, and to obtain more uniform luminance throughout the surface to increase the inspection reliability and productivity To provide a lighting device.

According to one aspect of the present invention for achieving the above object, an automatic optical inspection system for optically inspecting a fine pattern of a printed circuit board, has a plurality of first and second light sources, An illumination device for irradiating light from the two light sources to the printed circuit board; An image sensor reflecting the irradiated light through the printed circuit board and receiving the reflected light to obtain an image of the printed circuit board; An image processing apparatus which receives the image and determines whether a pattern of the printed circuit board is defective; The illumination device is provided between the printed circuit board and the image sensor, irradiates about a flat portion of the pattern using the first light sources, and uses an edge portion of the pattern using the second light sources. Investigate.

In a preferred embodiment of this feature, the lighting device comprises; The first and second light sources are provided as a module, and receive the light from the first light sources and the first light sources, output the light to the printed circuit board, and reflect the light from the printed circuit board. It receives the beam splitter for outputting to the image sensor and irradiates around the planar portion of the pattern. The lighting device includes the second light sources and a condenser lens that receives the light from the second light sources, collects the light, and outputs the light. In this case, the second light source is preferably provided to adjust the angle of incidence of the light to be irradiated around the edge portion. In this case, the second light source may adjust the incident angle automatically or manually.

According to another aspect of the present invention for achieving the above object, the inspection method of the automatic optical inspection system having a plurality of first and second light sources for inspecting the quality of the printed circuit board, the first and the first Irradiating an optical signal from the light sources onto the printed circuit board pattern; Acquiring image data of a plane / edge portion of the printed circuit board pattern in response to the optical signal emitted from the first / second light sources; And determining the quality of the printed circuit board from the obtained image data.

In a preferred embodiment of this feature, the step of investigating; The first light sources irradiate around the planar portion of the printed circuit board pattern, and the second light sources irradiate about the edge portion. In this case, the method may further include adjusting an incident angle of the reflected light to irradiate the second light sources about the edge portion.

According to another aspect of the present invention for achieving the above object, the illumination device provided in the automatic optical inspection system for inspecting a printed circuit board using an image sensor, the reflected light output to the planar portion of the printed circuit board pattern. At least one first light source; A beam splitter which receives the reflected light from the first light source and outputs the reflected light to the printed circuit board, and receives the reflected light from the printed circuit board and outputs the reflected light to the image sensor; Including at least one second light source for outputting reflected light to the edge portion of the printed circuit board pattern, to improve the uniformity of the brightness when the image of the fine pattern of the printed circuit board is acquired.

In a preferred embodiment of this feature, the illumination device is provided as a module, the second light source is provided to be able to adjust the incident angle of the reflected light to be irradiated to the edge portion. The lighting apparatus may further include a condensing lens that receives the reflected light from the second light source and condenses and outputs the reflected light.

Accordingly, according to the present invention, the automatic optical inspection system uses a first light source and a second light source to irradiate a second light source centered on an edge region of a pattern in inspecting a surface of a product on which a printed circuit board surface is reflective. Acquire accurate image data of the edge region of the pattern that could not be obtained by the light source.

DETAILED DESCRIPTION Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

1 is a perspective view showing the configuration of a lighting apparatus according to the present invention.

Referring to FIG. 1, the lighting device 110 is a device applied to an automatic optical inspection system 100 that inspects a defect of a printed circuit board pattern, and includes a plurality of first light sources 112 and a second light source 116. ) And a beam splitter 114. In addition, the lighting device 110 forms the first and second light sources 112 and 116 into one module.

Accordingly, the lighting device 110 emits light from the first light source 112 and irradiates light onto the beam splitter 114 to shine light around a printed circuit board surface, that is, a planar portion of the pattern 104. It becomes. At this time, the light irradiated vertically on the surface of the printed circuit board is vertically reflected from the beam splitter 114 and refracted again toward the irradiated side. The refracted light passes through the beam splitter 114 to transmit an image corresponding to the planar portion of the pattern 104 to the image sensor 102.

The lighting device 110 outputs light from the second light source 116 to shine light around the printed circuit board surface, that is, the edge portion of the pattern 104. At this time, the incident angle of light is automatically or manually adjusted so that the second light source 116 is irradiated around the edge portion of the pattern 104. Accordingly, the light output from the second light source 116 is irradiated around the edge portion of the printed circuit board pattern 104, and then the edge of the pattern 104 to the image sensor 102 through the beam splitter 114. Deliver the video corresponding to the part.

Accordingly, the illumination device 110 may emit light to obtain image data using the first and second light sources 112 and 116 to examine the reflective pattern of the surface of the printed circuit board. Investigate separately. Of course, the light irradiation area is not exactly distinguished due to the nature of the light. In other words, the boundary regions of the planar portion and the edge portion receive light from both the first and second light sources. Therefore, in the present invention, the description is divided into a planar portion and an edge portion, but this is for the purpose of clearly describing the technical features of the present invention and is not intended to limit the technical idea.

FIG. 2 is a cross-sectional view showing the configuration of an automatic optical inspection system having the illumination device shown in FIG. 1.

Referring to FIG. 2, the automatic optical inspection system 100 includes the illumination device 110 and is connected to the image processing device 120.

As shown in FIG. 1, the lighting device 110 is provided between the printed circuit board 104 and the image sensor 102 to planarize the pattern 104 using the first light sources 112. Irradiating around the portion (b), and irradiating around the edge portion (cb) of the pattern using the second light sources (116). The planar portion b is an image region obtained by using the first light source 112, and the edge portion is an image region obtained by using the second light source 116. except for b). Therefore, according to the present invention, the first and second light sources 112 and 116 are used to acquire image data of the image area c of the planar portion b and the edge portions c-b.

In detail, the lighting device 110 includes the first and second light sources 112 and 116 as one module, and the first light sources 112 and the first light sources 112. And a beam splitter 114 for receiving the light from the light and outputting the light to the printed circuit board 104 and receiving the light reflected from the printed circuit board 104 and outputting the light to the image sensor 102. In this case, the first light sources 112 irradiate around the planar portion b of the pattern 104. The edge portion cb of the pattern 104 may further include a second light source 116 and a condenser lens 118 that receives the light from the second light sources 116, collects the light, and outputs the light. Investigate around the center. In this case, the second light source is controlled to be irradiated about the edge portion by a control device (for example, an image processing device), and is provided to automatically or manually adjust the incident angle of the light.

The image processing apparatus 120 is provided with a typical computer system, a programmable logic controller, and the like to control and process various operations according to automatic optical inspection. The image processing apparatus 120 receives the image from the image sensor 102 and determines the pattern of the printed circuit board 104.

Here, the conventional lighting device (not shown) includes a first or second light source to irradiate the reflected light, so that the surface of the printed circuit board pattern is obtained from the beam splitter in order to obtain image data on the reflective surface such as a mirror. Light incident vertically on the test object is passed back through the beam splitter to the image sensor, where only image data can be obtained from an image area obtained using a single light source. However, in order to actually inspect the pattern, as illustrated in FIG. 2, image data of a corresponding region must be acquired and inspected using the first and second light sources 112 and 116.

Therefore, the present invention, by using the second light source 116 together with the first light source 112, by inspecting the printed circuit board of the reflective surface of the product surface, such as a mirror, it could not be accurately obtained by the first light source 112 Image data of an area of the pattern, that is, an edge portion, is accurately acquired and inspected using the second light source 116.

At this time, the angle adjustment of the second light source may be automatically or manually adjusted to obtain image data and higher data brightness of the edge portion of the pattern through the incident angle of the second light source 116. Of course, it will be apparent to those skilled in the art that the second light source 116 is fixed by setting an accurate angle of incidence in design.

Therefore, the automatic optical inspection system 110 uses the first light source and the second light sources 112 and 116 to use the second light source 116 to inspect the surface of the product where the surface of the printed circuit board 104 is reflective. In addition, accurate inspection of the printed circuit board 104 is performed by acquiring accurate image data of the edge region of the pattern 104 which cannot be obtained by the first light source 112. Obviously, the automatic optical inspection system 100 inspects printed circuit boards having different properties (eg, TAB substrates) using only the first light source 112 or the second light source 116.

3 is a view showing a pattern of a printed circuit board according to an embodiment of the present invention, Figures 4a and 4b is a waveform diagram comparing the brightness and uniformity of the brightness of the specific measurement position of the pattern by the prior art and the present invention admit.

Referring to FIGS. 4A and 4B, a profile representing brightness and uniformity of image data obtained by using a fine pattern of a printed circuit board, that is, a specific measurement position 130 shown in FIG. 132 and profile 134 according to the present invention are shown.

The profile 132 of FIG. 4A is irregularly formed between about 200 to 250 levels of brightness uniformity, and the lowest value is formed to 200 levels or less even in brightness. However, the profile 134 of FIG. It can be seen that the brightness uniformity is formed very regularly between about 240 to 250 levels using the light sources 112 and 116, and the lowest part is formed at almost 240 levels or more even in the brightness.

Therefore, comparing these two profiles 132 and 134, it can be seen that the lighting device 110 of the present invention is improved brightness of about 30% or more.

5 is a flowchart showing the inspection procedure of the optical inspection system provided with the illumination device of the present invention. This procedure is a program executed by the image processing apparatus 120, and the program is stored in a memory (not shown) of the image processing apparatus 120.

Referring to FIG. 5, the image processing apparatus 120 irradiates light to the printed circuit board 104 using the first and second light sources 112 and 116 in step S150. In this case, the first light sources 112 irradiate the center of the planar portion of the printed circuit board pattern 104, and the second light sources 116 irradiate the center of the edge portion. In addition, the incident angle of the light is adjusted so that the second light sources 116 irradiate around the edge portion.

In operation S152, image data of a planar portion and an edge portion of the printed circuit board pattern 104 may be acquired in response to the optical signals emitted from the first and second light sources 112 and 116, respectively. In operation S154, the quality of the printed circuit board pattern 104 may be determined from the obtained image data.

As described above, there are TAB and COF substrates in printed circuit boards in the form of films and tapes, and these two types of substrates have different surface features.

First of all, the TAB substrate has a diffusion surface with various surface angles formed on the surface of the pattern, and most of them react to light coming from various angles of incidence. However, in the COF substrate, as described above, the product surface is formed of a reflective surface such as a mirror. Therefore, such products have usually used lighting devices (eg, lighting devices using a beam splitter, etc.) in which an angle of incidence for irradiating an inspection object is formed perpendicular to the image sensor. However, such a lighting apparatus has a problem in that image data of a specific portion of the pattern is not accurately captured as the pattern of the printed circuit board is miniaturized.

In particular, in inspecting a COF substrate in a film or tape type substrate, the COF substrate has a very reflective surface because its surface is similar to a mirror. The light is transmitted to the image sensor only when the incident angle of light shining on the inspection object of the COF substrate is irradiated perpendicularly to the image sensor. For this reason, as the pattern on the substrate becomes finer at the same time, the pattern upper surface, that is, the planar portion, and both end surfaces, or the edge portion, of the pattern in the shape of the pattern are changed differently from the technical aspects. When such a product is irradiated under the same lighting conditions, it is difficult to optimally inspect the image at both ends of the pattern as the image data at both ends of the pattern cannot be obtained through the image sensor unlike the image at the pattern center surface.

Therefore, the present invention reduces the image loss at both ends of the pattern of the substrate, where the product surface has a highly reflective surface similar to the effect of the mirror, and also provides a light splitter to the beam splitter in a lighting device that emits light through the beam splitter. Due to the loss of light when direct light is emitted, it is possible to improve the overall brightness of the light reflected through the inspection object and pass through the image sensor, so it is most suitable for the inspection of increasingly patterned film and tape printed circuit boards. You can get an image of

As described above, the illumination device of the present invention, at the time of optical inspection of each TAB, COF substrate, to improve the brightness and uniformity of each of the first light and the second light, especially the angle to irradiate the inspection object of the second light You can freely adjust to get the best image data.

In addition, the automatic optical inspection system including the lighting apparatus of the present invention uses the first and second light sources to acquire image data of the planar portion and the edge portion of the printed circuit board pattern, thereby inspecting the pattern, thereby enabling accurate inspection. This can prevent undetected and overdetected.

In addition, by equipping two types of substrates with different features on different surfaces in one module, it is possible to inspect both TAB and COF substrates with one illumination because optical inspection can be applied without replacing the lighting apparatus. Provide operator convenience of equipment operation.

Claims (15)

In an automated optical inspection system that optically inspects fine patterns on a printed circuit board: An illuminating device having a plurality of first and second light sources for irradiating light onto the printed circuit board; An image sensor receiving the light reflected from the printed circuit board and obtaining an image of the printed circuit board; An image processing apparatus which receives the image from the image sensor and determines whether a pattern of the printed circuit board is defective; And wherein the first light sources are arranged to irradiate about a planar portion of the pattern, and the second light sources are arranged to irradiate about an edge portion of the pattern. The method of claim 1, The lighting device; And the first and second light sources are provided in one module. The method according to claim 1 or 2, The lighting device; A beam splitter configured to receive the light from the first light sources and output the light to the printed circuit board, and to receive the reflected light from the printed circuit board and output the light to the image sensor; Automated optical inspection system, characterized in that the irradiation in the center. The method of claim 3, wherein The lighting device; And a condenser lens that receives the light from the second light sources, condenses and outputs the light, and emits light about the edge portion of the pattern. The method of claim 1, And the second light source is configured to adjust an angle of incidence of the light to be irradiated about the edge portion. In the inspection method of the automatic optical inspection system having a plurality of first and second light sources for inspecting the quality of the printed circuit board: The first light sources irradiating an optical signal about a planar portion of the printed circuit board pattern, and the second light sources irradiating an optical signal around an edge portion of the printed circuit board pattern; Acquiring image data of the printed circuit board pattern using light reflected from the printed circuit board; And determining the quality of the printed circuit board from the obtained image data. The method of claim 6, And the edge portion of the printed circuit board pattern is rounded. The method according to claim 6 or 7, The investigating step; And adjusting the angle of incidence of the light such that the second light sources irradiate about the edge portion. delete delete delete delete The method according to claim 1 or 2, The illumination device is an automatic optical inspection system, characterized in that provided between the printed circuit board and the image sensor. The method according to claim 1 or 2, And the second light sources irradiate the light about a rounded edge portion of the printed circuit board pattern. delete

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