TW201527744A - Test apparatus, test system and test method of defects in blind vias of printed circuit board - Google Patents

Abstract

Test apparatus, test system and test method of defects in blind vias of a printed circuit board are provided to test the defects in the blind vias of the printed circuit board by casting a light ray on the printed circuit board and capturing images of the printed circuit board, characterized in that the wavelength of the light ray is that of invisible light. Unlike the prior art, the present invention is effective in detecting defects on metallic conductive contacts at the bottoms of the blind vias in a printed circuit board appearance test stage and thereby enhancing greatly the test precision of an appearance test procedure and the reliability of the quality of printed circuit boards which pass the test.

Description

Detection device, detection system and detection method for defect in blind hole of circuit board

The invention relates to an optical detecting device, a detecting system and a detecting method thereof, and more particularly to a detecting device, a detecting system and a detecting method for a defect in a blind hole of a circuit board.

The light source system plays a pivotal role in automatic optical inspection (AOI). For example, precision automated optical inspection is required in the manufacture of liquid crystal displays, wafers of semiconductor integrated circuits, and related printed circuits to ensure the quality of finished products.

The detection on the circuit board is usually for the inspection of whether the metal wire line or the conductive contact pad is defective. Traditionally, the illumination light in the visible light band is forwardly irradiated to the object to be tested, since the wire is generally made of a metal material (for example: The copper material) is therefore highly reflective, and it is judged whether or not the wire is broken, broken or stained by the presence or absence of the reflected light of the illuminating light in the forward direction.

In the trend that the electronic components inside the electronic device are constantly shrinking, the circuit board is often stacked with several layers of wiring structures, and the insulation structure between the two layers of wires is required when the interconnection between different layers is required for interconnection conduction. A blind hole is formed in the resin layer (the resin layer), and the bottom of the blind hole can expose the conductive contact of the lower layer, and then fills the conductive material into the blind hole to electrically connect the conductive connection of the lower layer. Point the wire with the upper line.

When a blind hole is opened, it is easy to stain the conductive contact on the bottom of the conductive contact during the manufacturing process or even damage the conductive contact. However, the existing automatic optical detection often detects the appearance of the circuit board due to the blind hole. Difficult to be irradiated to visible light, resulting in difficulty in obtaining the image of the conductive contact at the bottom of the blind hole. As shown in Fig. 1, it is the image data obtained at the blind hole under the detection of the general circuit board appearance detector. Since the depth ratio of the blind hole is nearly 1:1, the deep blind hole allows the image at the blind hole to show only a black color, and the image of the conductive contact at the bottom of the blind hole cannot be obtained, thereby causing Effective appearance inspection of the conductive contacts at the bottom of the blind hole is not possible.

One of the objects of the present invention is to enable effective visual inspection of conductive contacts at the bottom of blind vias.

To achieve the above and other objects, the present invention provides a detection system for a defect in a blind hole of a circuit board, which is performed by illuminating an illumination source of the circuit board and capturing an image of the printed circuit board. The detection of defects in the blind holes of the board is characterized in that the wavelength band of the light source is a wavelength section of invisible light.

In order to achieve the above and other objects, the present invention provides a method for detecting a defect in a blind hole of a circuit board, comprising the steps of: illuminating a circuit board to be tested with illumination light of an invisible wavelength band; and extracting a circuit board to be tested. Image data; identifying a contour of a bottom of the blind hole according to the image data; determining whether there is a defect in the bottom portion of the blind hole according to the contour; and outputting the identification result.

In order to achieve the above and other objects, the present invention further provides a device for detecting a defect in a blind hole of a circuit board, comprising: a carrier having a to-be-detected area for carrying the circuit board; and a light source generating device configured An image capturing device is disposed above the loading platform for obtaining an image of the circuit board on the to-be-detected area. And a computing host connected to the image capturing device for comparing the image data with a preset metal line image data to identify the contour of the bottom of the blind hole and performing defect in the bottom portion of the blind hole Identification.

In an embodiment of the invention, the illumination source is incident on the circuit board at an incident angle of no more than 50 degrees.

In an embodiment of the invention, the wavelength range of the invisible light is 850 to 950 nm.

In an embodiment of the invention, the light source generating device comprises two light source illuminators located above the two sides of the to-be-detected area to provide symmetrical incident light to the area to be inspected.

In an embodiment of the invention, the light source generating device is in an annular configuration to provide enclosed illumination light to the detection region.

Therefore, the present invention detects the circuit board by using invisible light as the illumination light, so that defects on the metal conductive contacts at the bottom of the blind hole can be effectively detected in the appearance detection stage of the circuit board, which can be avoided. The conventional technology cannot detect the defect at the bottom of the blind hole, thereby greatly improving the detection accuracy of the appearance inspection program and the quality reliability of the board through which the inspection is performed.

In order to fully understand the objects, features and advantages of the present invention, the present invention will be described in detail by the following specific embodiments and the accompanying drawings.

First, please refer to Figure 2, which is a schematic diagram of the blind hole structure of the circuit board. The blind vias 200 are disposed to provide a path through which the metal lines 110 and the conductive contacts 120 on the upper and lower sides of the insulating layer 101 can be electrically connected within the circuit board 100. The blind hole 200 is opened at the conductive contact 120 at the bottom of the insulating layer 101 to expose the conductive contact 120, and then the conductive material is filled in the blind hole (not shown). The purpose of electrically connecting the metal lines on the upper and lower sides of the insulating layer 101 is achieved. However, since the blind hole 200 is easy to be attached to the conductive contact 120 at the bottom during the manufacturing process, or the conductive contact is damaged, the detection device, the detection system and the detection method thereof described in the present invention can be The conductive contact 120 at the bottom of the blind hole 200 performs further visual inspection. Once the conductive contact 120 is damaged or the conductive contact top surface 122 is contaminated with dirt, it can be detected.

Next, please refer to FIG. 3, which is a schematic diagram of a circuit board detecting apparatus in an embodiment of the present invention. The detecting device for the defect in the blind hole of the circuit board comprises: a carrying platform 310, a light source generating device 330, an image capturing device 350, and a computing host 370.

The carrier 310 has a to-be-detected area for carrying the circuit board 100. The light source generating device 330 is disposed above the carrying platform 310 for illuminating the to-be-detected area with the illumination light of the invisible wavelength band. The image capturing device 350 is disposed above the carrying platform 310 for acquiring image data of the circuit board 100 to be tested on the to-be-detected area. The computing host 370 is connected to the image capturing device 350 for comparing the image data with a predetermined metal line image data to identify the contour of the bottom of the blind hole and to identify the defect in the bottom portion of the blind hole.

The present invention uses the illumination source of the circuit board 100 and the image of the circuit board 100 to detect the defects in the blind hole of the circuit board 100, and uses the light source of the invisible wavelength band as the illumination. The light source allows the bottom image of the blind hole to be taken out, and the image can be detected for defects. Due to the use of a light source in the wavelength range of invisible light, the hole wall of the blind hole can accurately locate the algorithm running in the computing host 370 (see Figure 6), and then the conductive contact portion at the bottom. It is judged whether there are defects such as residual glue and foreign matter. In contrast, the image data obtained by the conventional technology (see Fig. 1) cannot determine the bottom of the blind hole.

In order to obtain a better image effect, the light source generating device 330 is preferably incident on the circuit board 100 at an incident angle of not more than 50 degrees, that is, ±50 degrees on the normal line of the detection area for the detection area. The angle of incidence within the beam is the preferred angle of illumination. In addition, another preferred condition is that the invisible light having a wavelength band limited between 850 and 950 nm can be added. It will be appreciated by those skilled in the art that the light source generating device 330 is exemplified by a single light source generator in FIG. 3, and the use of other numbers of light source generators is also applicable to the present invention.

4 is a schematic diagram of a circuit board detecting apparatus according to another embodiment of the present invention, which differs from FIG. 3 in that the light source generating apparatus 330 includes two light source illuminators located at the to-be-checked Above the sides of the zone, symmetrical incident light is provided to the zone to be inspected.

Next, please refer to FIG. 5, which is a cross-sectional view of the light source generating device of the present invention in an embodiment. As described above, the light source generating device 330 of the present invention may be a configuration of a single light source generator, a symmetric opposite arrangement of two light source generators (as shown in FIG. 4) or as shown in FIG. The configuration of a single annular light source generator that will provide a more adequate illumination source. Wherein, the fifth figure is shown in a sectional view, and the light rays generated by the annular light source generator are incident on the circuit board 100 at an incident angle of not more than 50 degrees.

FIG. 6 is a flowchart of a circuit board detecting method for a defect in a blind hole according to an embodiment of the present invention, including: Step S101: illuminating a circuit board to be tested with illumination light of an invisible wavelength band; Step S103 : capturing the image data of the circuit board to be tested; step S105: identifying the contour of the bottom of the blind hole according to the image data; step S107: performing identification of the defect in the bottom portion of the blind hole according to the contour; and step S109: outputting The identification result. Among them, the better detection conditions (incident angle, invisible light band) have been discussed before, and will not be described here.

Next, please refer to Fig. 7, which is the image data at the blind hole obtained under the detection means of the present invention. As shown in the figure, in the use of the invisible light of the present invention, the outline of the blind hole is clearly visible, so that the algorithm for analyzing the image data can easily grasp the outline of the blind hole, and thus can be preset with The line data (for example, circuit design drawing) is compared, and not only can be used to detect whether the bottom area of the blind hole is exposed to a desired value, but also the condition of the surface of the conductive contact at the bottom of the blind hole can be detected. When there are defects such as residual glue and foreign matter on the surface of the contact, it can be easily detected.

In summary, the present invention detects the circuit board by using invisible light as the illumination light, so that defects on the metal conductive contacts at the bottom of the blind hole can be effectively detected in the appearance detection stage of the circuit board. It can be avoided that the conventional technology cannot detect the defect at the bottom of the blind hole, thereby greatly improving the detection accuracy of the appearance inspection program and the quality reliability of the board through which the inspection is performed.

The invention has been described above in terms of the preferred embodiments, and it should be understood by those skilled in the art that the present invention is not intended to limit the scope of the invention. It should be noted that variations and permutations equivalent to those of the embodiments are intended to be included within the scope of the present invention. Therefore, the scope of protection of the present invention is defined by the scope of the patent application.

100‧‧‧ boards
101‧‧‧Insulation
110‧‧‧Metal lines
120‧‧‧Electrical contacts
122‧‧‧Top surface of conductive contacts
200‧‧ ‧ blind hole
310‧‧‧bearing station
330‧‧‧Light source generating device
350‧‧‧Image capture device
370‧‧‧ computing host
S101~S109‧‧‧Steps

The first figure is the image data obtained by the conventional circuit board appearance detection technology with blind holes. Figure 2 is a schematic diagram of the blind hole structure of the circuit board. Figure 3 is a schematic diagram of a circuit board detecting apparatus in an embodiment of the present invention. Figure 4 is a schematic diagram of a circuit board detecting apparatus in another embodiment of the present invention. Fig. 5 is a schematic cross-sectional view showing a light source generating device of the present invention in an embodiment. Figure 6 is a flow chart showing a method for detecting a circuit board in a blind hole in an embodiment of the present invention. Figure 7 is the image data at the blind hole obtained under the detection means of the present invention.

S101~S109‧‧‧Steps

Claims (11)

A detection system for a defect in a blind hole of a circuit board is characterized in that a defect in a blind hole of the circuit board is detected by illuminating an illumination source of the circuit board and capturing an image of the circuit board. : The wavelength band of the light source is a wavelength segment of invisible light. The detection system of claim 1, wherein the illumination source is incident on the circuit board at an incident angle of no more than 50 degrees. The detection system of claim 2, wherein the wavelength range of the invisible light is 850 to 950 nm. A method for detecting defects in a blind hole of a circuit board, comprising the steps of: illuminating a circuit board to be tested with illumination light of an invisible wavelength band; capturing image data of the circuit board to be tested; and identifying a bottom of the blind hole according to the image data The contour of the bottom of the blind hole is identified according to the contour; and the identification result is output. The detecting method of claim 4, wherein the illuminating light is incident on the circuit board to be tested at an incident angle of not more than 50 degrees. The detection method according to Item 5, wherein the wavelength range of the invisible light is 850 to 950 nm. A device for detecting a defect in a blind hole of a circuit board, comprising: a carrying platform having a to-be-detected area for carrying the circuit board; and a light source generating device disposed above the carrying platform for using an invisible wavelength The illuminating light of the segment illuminates the area to be inspected; an image capturing device is disposed above the carrying platform for acquiring image data of the circuit board on the area to be inspected; and a computing host is connected to the image 撷The device is configured to compare the image data with a preset metal line image data to identify the contour of the bottom of the blind hole and identify the defect in the bottom portion of the blind hole. The detecting device of claim 7, wherein the light source generating means causes the illumination light to be incident on the inspection area at an incident angle of not more than 50 degrees. The detecting device according to claim 8, wherein the invisible light has a wavelength band of 850 to 950 nm. The detecting device according to any one of claims 7-9, wherein the light source generating device comprises two light source illuminators located above two sides of the to-be-detected area to provide symmetry to the area to be inspected. Incident light. The detecting device according to any one of claims 7-9, wherein the light source generating device is in an annular configuration to provide enclosing illumination light to the detection region.