KR100797668B1 - Printed circuit board and manufacturing method of the same - Google Patents

Abstract

The present invention relates to a printed circuit board having a low defect rate and excellent productivity and a method of manufacturing the same. In the method of manufacturing a printed circuit board according to the present invention, (a) forming a circuit pattern and a bonding pad in a circuit region, and (b) forming a protective film having a top surface higher than the upper surface of the bonding pad in a dummy region. Characterized in that it comprises a step.

Printed Circuit Board, Bonding Pad, Protective Film, Dummy Area

Description

Printed circuit board and manufacturing method thereof {PRINTED CIRCUIT BOARD AND MANUFACTURING METHOD OF THE SAME}

1 is a plan view illustrating a printed circuit board according to an exemplary embodiment of the present invention.

FIG. 2 is a schematic cross-sectional view taken along lines II-II 'and III-III' of FIG. 1.

3A to 3C are cross-sectional views schematically illustrating a method of manufacturing a printed circuit board according to an exemplary embodiment of the present invention.

4 is a diagram illustrating a process of forming a protective film in a method of manufacturing a printed circuit board according to an exemplary embodiment of the present invention.

Description of the main parts of the drawing

10: printed circuit board 12: base substrate

12a: upper surface of the base substrate 20: circuit area

22: bonding pad 22a: upper surface of the bonding pad

26: copper foil 27: electroless copper plating layer

28 electrolytic copper plating layer 30 dummy area

32: solder resist 32a: upper surface of the solder resist

34: protective film 34a: upper surface of a protective film

40 mask 42 peelable material

The present invention relates to a printed circuit board and a manufacturing method thereof, and more particularly, to a printed circuit board and a manufacturing method thereof having a low defect rate and excellent productivity.

Printed circuit boards are the most basic electronic components used in electronic communication devices and the like, and the technology of printed circuit boards is also rapidly developing with the rapid development of electronic communication technology. In order to improve the performance of electronic communication devices, research is being conducted to improve the performance of printed circuit boards and to reduce the defective rate.

Since the wound of the printed circuit board may cause the defect of the printed circuit board, it is very important to manage it effectively. Analysis of printed circuit board wounds by type revealed that about 80% of scratches caused by roughness occurred during process handling. That is, it can be seen that more wounds occur during process handling than wounds caused by accidents such as stamping and scratching. Accordingly, there is a need for a technique for reducing scratches caused by contact or friction occurring during process handling.

In general, since the upper surface of the bonding pad is formed higher than other portions, the upper surface of the bonding pad is brought into contact with another printed circuit board or the process apparatus during process handling, so that the bonding pad may be easily scratched due to grazing. In fact, the defects generated in the bonding pads were found to be 90% or more of the total defects.

By the way, the bonding pads function as entrances and outlets for supplying external power, and thus are defect-free management sites where no wounds are allowed, and the wounds on the bonding pads are a direct cause of defective printed circuit boards. As described above, a defect due to grazing property tends to occur in a bonding pad in which conventional wounds are not allowed. Thus, a defect rate of a printed circuit board is high.

In order to prevent such a problem, a method of inserting a gap between printed circuit boards to prevent the printed circuit board from directly contacting another printed circuit board or the like is used.

However, even in this case, the bonding pads of the printed circuit board may come into contact with the interleaver and cause scratches on the bonding pads. In addition, the cost increases due to the use of consumables, which are consumables, and a process of inserting and removing interlayers between printed circuit boards is added to increase costs and processing time.

The present invention was devised to solve the above problems, and an object of the present invention is to provide a printed circuit board having a low incidence of a wound of a bonding pad by improving the structure.

In addition, another object of the present invention is to provide a method of manufacturing a printed circuit board that can prevent the occurrence of damage to the connection pad without using a sheet of paper, as well as reduce the cost and processing time.

In order to achieve the above object, a method of manufacturing a printed circuit board according to the present invention, (a) forming a circuit pattern and a bonding pad in the circuit area, and (b) in the dummy area than the upper surface of the bonding pad Forming a protective film having a high top surface.

In the present invention, in the step (b), the protective film is formed by a printing method or a film laminating method.

In the present invention, in the step (b), the protective film is formed by applying a peelable material by a printing method.

In the present invention, the protective film is characterized in that it comprises a vinyl resin or a vinyl resin derivative.

In the present invention, the protective film is characterized in that the thickness of 25㎛ 50㎛.

In the present invention, the upper surface of the bonding pad is characterized by consisting of a gold plated film formed by a gold plating method.

In the present invention, the upper surface of the bonding pad is characterized by consisting of an electrolytic gold plated film formed by the electrolytic gold plating method.

In the present invention, before the step (b), the step of forming a solder resist in the dummy region, characterized in that further performing.

 In the present invention, after the step (b), characterized in that for performing the step of removing the protective film.

On the other hand, the printed circuit board according to the present invention, at least one circuit region in which the circuit pattern and the bonding pad is formed, a dummy region formed outside the circuit region, and formed in the dummy region than the upper surface of the bonding pad And a protective film having a high top surface.

In the present invention, the protective film is made of a peelable material.

In the present invention, the protective film is characterized in that it comprises a vinyl resin or a vinyl resin derivative.

In the present invention, the protective film is characterized in that the thickness of 25㎛ 50㎛.

In the present invention, the upper surface of the bonding pad is characterized by consisting of a gold plated film.

In the present invention, the upper surface of the bonding pad is characterized by consisting of an electrolytic gold plated film.

In the present invention, the dummy region is characterized in that it further comprises a solder resist formed under the protective film.

Hereinafter, a printed circuit board and a manufacturing method thereof according to an embodiment of the present invention will be described in detail with reference to the accompanying drawings.

First, a printed circuit board according to an exemplary embodiment of the present invention will be described with reference to FIGS. 1 and 2.

1 is a plan view illustrating a printed circuit board 10 according to an exemplary embodiment of the present invention, and FIG. 2 is a schematic cross-sectional view taken along lines II-II 'and III-III' of FIG. 1.

Referring to the drawings, the printed circuit board 10 according to the present embodiment includes at least one circuit region 20 and a dummy region 30 formed outside the circuit region 20.

Here, the circuit region 20 refers to a region in which a circuit pattern (not shown) and the bonding pads 22 are formed. In the present embodiment, a plurality of such circuit regions 20 are provided. In the present specification, the circuit region 20 is referred to for the sake of clarity. However, the circuit regions 20 formed in the present exemplary embodiment may be separated from each other to substantially function as one printed circuit board.

However, the present invention is not limited thereto and only one circuit region 20 may be formed on the printed circuit board 10 so that the present invention may be used without being separated, which is also within the scope of the present invention.

The circuit pattern formed in the circuit region 20 may be formed inside and / or outside the base substrate 12, and may be formed in one layer or multiple layers. In the present embodiment, although the circuit pattern is formed in the portions 24 connecting the two different bonding pads 22 in FIG. 1, the circuit pattern may be specifically considered in consideration of the fact that the circuit pattern may have various shapes and arrangements. Not shown. The circuit pattern formed in the circuit region 20 may be made of copper foil. However, the present invention is not limited thereto and may be composed of a film containing various materials other than copper foil.

The bonding pad 22 serves to receive external power by wire bonding. Although wire bonding has been described as an example, the present invention is not limited thereto and various bonding methods other than wire bonding may be applied.

The upper surface 22a of the bonding pad 22 is preferably made of a material having excellent conductivity in order to prevent poor contact and improve electrical characteristics. In consideration of this, in the present embodiment, the bonding pad 22 includes a nickel plated film 27 and a gold plated film 28 that are sequentially stacked on the copper foil 26 constituting a part of the circuit pattern. That is, the upper surface 22a of the bonding pad 22 is composed of a gold plated film 28, which may be an electrolytic gold plated film 28 formed by an electroplating method. However, the present invention is not limited thereto, and the upper surface 22a of the bonding pad 22 may be made of another material.

On the other hand, the dummy region 30 refers to a region formed outside the circuit region 20 and which does not substantially contribute to the operation of the printed circuit board 10 because the circuit pattern and the bonding pads 22 are not formed. .

In this dummy region 30, a solder resist 32 and a protective film 34 are sequentially formed.

The solder resist 32 is formed on a portion other than the bonding pads 22 connected to the outside for supplying power and exchanging signals, and is formed on at least the entire surface of the dummy region 30.

The protective film 34 formed on the solder resist 32 may be formed to have a predetermined thickness so that the upper surface 34a of the protective film 34 is higher than the upper surface 22a of the bonding pad 22. Make sure Here, the upper surface 22a of the bonding pad 22 is formed to be higher, so that the upper surface 22a of the bonding pad 22 is the surface of the base substrate 12 than the upper surface 34a of the protective film 34. It means farther away from (12a).

The thickness of the protective film 34 may be determined in consideration of the step between the upper surface 22a of the bonding pad 22 and the upper surface 32a of the solder resist 32. For example, when the step difference between the upper surface 22a of the bonding pad 22 and the upper surface 32a of the solder resist 32 is about 20 μm, the protective film 34 is formed to a thickness of about 25 μm to 50 μm. Thus, the upper surface 22a of the bonding pad 22 can be formed 10 µm or more higher than the upper surface 34a of the protective film 34. However, the thickness of the passivation layer 34 is merely an example, and the thickness of the top surface 34a of the passivation layer 34 may be higher than that of the top surface 22a of the bonding pad 22.

In the present embodiment, as described above, the upper surface 34a of the protective film 34 is formed higher than the upper surface 22a of the bonding pad 22, so that the printed circuit board 10 is different from the printed circuit board 10 during the process handling. Bonding pads 22 do not contact them even if they are brought into contact with the device (not shown) or the device (not shown).

Accordingly, it is possible to minimize the occurrence of scratches due to grazing on the bonding pad 22. In addition, it is also possible to reduce the occurrence of accidental scratches such as scratching and chipping in the bonding pad 22.

 In the present embodiment, since the protective film 34 can be formed to minimize the occurrence of the wound on the bonding pad 22, it is possible to avoid using the paper used in the past to prevent the occurrence of the wound. By not using the consumables, consumables can be saved, as well as the cost and process time due to the insertion and removal of the sheets.

That is, in this embodiment, the defective rate that may occur in the bonding pad 22 may be reduced, and productivity may be greatly improved by not using an interlayer paper. This can be further exerted when the upper surface 22a of the bonding pad 22 is made of an electrolytic gold plated film 28 of relatively low strength as in this embodiment.

The protective film 34 may be made of vinyl resin or a vinyl resin derivative as a main component, and a plasticizer, a color additive, an antifoam, a thixotropic additive, or the like may be added. As the vinyl resin or the vinyl resin derivative, various materials such as polyvinyl acetal, polyvinyl formal, polyvinyl alcohol, polyvinyl chloride, vinyl chloride, polyvinyl acetate, vinyl acetate and the like may be used.

Here, the protective film 34 may be made of a peelable material to be removed as necessary.

In the above, the upper surface 32a of the solder resist 32 formed in the dummy region 30 is lower than the upper surface 22a of the bonding pad 22. However, the present invention is not limited thereto. That is, even when the upper surface 32a of the solder resist 32 formed in the dummy region 30 is higher than the upper surface 22a of the bonding pad 22, a protective film ( 34), which is also within the scope of the present invention.

Hereinafter, a method of manufacturing a printed circuit board according to an exemplary embodiment of the present invention will be described with reference to FIGS. 3A to 3C. 3A to 3C are cross-sectional views schematically illustrating a method of manufacturing a printed circuit board 10 according to an exemplary embodiment of the present invention. 4 is a diagram illustrating a process of forming the protective film 34 in the method of manufacturing the printed circuit board 10 according to the exemplary embodiment of the present invention.

First, as shown in FIG. 3A, a circuit region 20 in which a bonding pad 22 or the like is formed, and a dummy region 30 formed outside the circuit region 20 and in which a solder resist 32 is formed are included. The printed circuit board 10 is prepared.

Various processes may be applied to the process of manufacturing the printed circuit board 10. For example, the copper foil 26 is formed according to the circuit pattern, and the solder resist 32 is formed to open only a portion to be connected to the outside for supplying power and exchanging signals, such as the bonding pad 22. The nickel plating film 27 and the gold plating film 28 may be sequentially formed on the portion scheduled as 22 to form the bonding pads 22.

The printed circuit board 10 of the present embodiment may be a multilayer printed circuit board (MLB) having a plurality of circuit layers. In this case, various methods such as build up may be used to form a plurality of circuit layers. Can be.

Subsequently, as shown in FIG. 3B, a protective film 34 is formed on the solder resist 32 formed in the dummy region 30. At this time, the protective film 34 is formed to a thickness such that the upper surface 34a of the protective film 34 can be positioned higher than the upper surface 22a of the bonding pad 22.

For example, the thickness of the passivation layer 34 may be 25 μm to 50 μm, and the passivation layer 34 may be made of a peelable material, and may include vinyl resin or a benyl resin derivative. When the protective film 34 is made of a peelable material, if a defect occurs during the protective film 34 forming process, only the portion where the defect has occurred can be peeled off and printed again, thereby improving productivity.

As shown in FIG. 4, the protective film 34 may be formed by applying a peelable material 42 or the like by a printing method using a mask 40 having an opening corresponding to the dummy region 30. . Alternatively, although not shown in the drawings, the protective film 34 may be formed by laminating the protective film by a film laminating method. In addition, the present invention is not limited thereto, and various methods for forming a protective film may be used.

As described above, the protective film 34 may be used as the printed circuit board 10. Alternatively, as shown in FIG. 3C, after the other process is performed, the process of removing the protective film 34 may be further performed and then used as the printed circuit board 10. As described above, in the present exemplary embodiment, since the protective film 34 is formed of a peelable material, it is possible to determine whether to remove the protective film 34 in consideration of the use of the printed circuit board 10.

Hereinafter, the present invention will be described in more detail with reference to experimental examples of the present invention. This experimental example is only for illustrating the present invention and the present invention is not limited thereto.

Experimental Example

A circuit pattern is formed of 35 μm thick copper foil in the circuit area, a 20 μm thick solder resist is formed in the dummy area, and then a 5 μm thick nickel plated film and a 0.5 μm thick electrolytic gold plated film are formed on the predetermined portion of the bonding pad. Bonding pads were formed. Subsequently, a 35 μm thick protective film including a vinyl resin derivative was formed on the solder resist.

After the printed circuit board was manufactured by performing other processes without using a sheet of paper, the printed circuit board was inspected for defects.

Comparative example

A printed circuit board was manufactured in the same manner as in Experimental Example, except that no protective film was formed and interlayer paper was used. The defective printed circuit board was examined.

After manufacturing 960,157 printed circuit boards and 752,305 printed circuit boards according to the comparative example, the defects of the printed circuit boards were examined. The results are shown in Table 1 below.

Total number Bad count  Defective rate Experimental Example 960, 157 18,243 1.9 Comparative example 752,305 71,469 9.5

As shown in Table 1, according to the experimental example of the present invention, even if no interleaved paper, the defective rate of the printed circuit board is only 1.9%, and it can be seen that the defect rate is significantly lower than that of the comparative example of 9.5%. This is because the upper surface of the bonding pad may be formed higher than the upper surface of the protective film formed in the dummy area, thereby minimizing the occurrence of a wound on the bonding pad due to contact or friction of another printed circuit board or the like.

That is, the embodiments and experimental examples of the present invention have been described above, but the present invention is not limited thereto, and the present invention is not limited thereto, and various modifications or changes are made within the scope of the claims and the appended drawings. It is of course possible that this also falls within the scope of the present invention.

As described above, according to the printed circuit board of the present invention, the upper surface of the protective film is formed higher than the upper surface of the bonding pad so that the bonding pad does not directly contact other printed circuit boards or devices, so that the wound is not caused by the bonding pad. This can be minimized. Therefore, when the printed circuit board is excellent in performance and applied to an electronic communication device, the performance and reliability of the electronic communication device can be improved.

On the other hand, according to the manufacturing method of the printed circuit board of the present invention, it is possible to minimize the defective rate of the printed circuit board caused by the wound on the bonding pad. In addition, since it is possible not to use the sheet, it is possible to reduce the cost of the sheet to be used as consumables, and to reduce the cost and processing time due to the insertion and removal of the sheet. Therefore, the productivity of the printed circuit board can be remarkably improved.

Claims (16)

In the manufacturing method of a printed circuit board comprising at least one circuit region and a dummy region formed outside the circuit region, (a) forming a circuit pattern and a bonding pad in the circuit area; (b) forming a solder resist in the dummy region; And (c) forming a passivation layer having a top surface higher than the top surface of the bonding pad in the dummy region where the solder resist is formed; Method of manufacturing a printed circuit board comprising a. The method of claim 1, wherein in the step (c), the protective film is formed by a printing method or a film laminating method. delete The method of claim 1, wherein the passivation layer comprises vinyl resin or a vinyl resin derivative. The method of claim 1, wherein the passivation layer has a thickness of 25 μm to 50 μm. The method of claim 1, wherein an upper surface of the bonding pad is formed of a gold plated film formed by a gold plating method. The method of claim 1, wherein an upper surface of the bonding pad is formed of an electrolytic gold plated film formed by an electrolytic gold plating method. delete The method of manufacturing a printed circuit board according to claim 1, further comprising, after step (c), removing the protective film. At least one circuit region in which circuit patterns and bonding pads are formed; A dummy region formed outside the circuit region; A passivation layer formed on the dummy region and having a top surface higher than that of the bonding pad; And A solder resist formed in the dummy region and formed under the passivation layer Printed circuit board comprising a. delete The printed circuit board of claim 10, wherein the protective layer comprises vinyl resin or a vinyl resin derivative. The printed circuit board of claim 10, wherein the passivation layer has a thickness of 25 μm to 50 μm. The printed circuit board of claim 10, wherein an upper surface of the bonding pad is formed of a gold plated film. The printed circuit board of claim 10, wherein an upper surface of the bonding pad is formed of an electrolytic gold plated film. delete

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