KR100809979B1 - Method for manufacturing printed circuit board - Google Patents

Abstract

A method for manufacturing a printed circuit board is provided to prevent a printing error by dualizing a curing process for a wiring unit and a pad. A method for manufacturing a printed circuit board includes the steps of: forming a pad pattern corresponding to a pad unit by discharging a conductive ink on a surface of a substrate(S10); temporarily curing the pad pattern(S20); forming a wiring pattern corresponding to a wiring unit by discharging the conductive ink on the surface of the substrate(S30); and completely curing the pad pattern and the wiring pattern(S40), wherein the conductive ink includes a light curing material, and the ultraviolet rays with predetermined energy is irradiated to the pad pattern in a temporarily curing step.

Description

Method for manufacturing printed circuit board

1 is a photograph showing a circuit pattern formed by a circuit board manufacturing method according to the prior art.

2 is a graph showing ultraviolet energy according to the distance between the substrate and the ultraviolet light source.

3 is a flow chart showing a circuit board manufacturing method according to an embodiment of the present invention.

Figure 4 is a process diagram showing a circuit board manufacturing method according to an embodiment of the present invention.

5 is a flow chart showing a circuit board manufacturing method according to an embodiment of the present invention.

6 is a photograph showing a pad pattern printing result according to ultraviolet irradiation energy.

<Explanation of symbols for the main parts of the drawings>

10: substrate 20: inkjet head

22: ink 24: pad portion

26: wiring portion 30: ultraviolet module

32: UV

The present invention relates to a circuit board manufacturing method.

In the circuit board manufacturing method according to the prior art, in order to form a circuit pattern, such as copper clad laminate (CCL) lamination, photolithography, etching, stripping, rinsing, drying The processes were carried out. This method has disadvantages in terms of time and cost due to the increase in the cost of the dry film and mask to perform the exposure process and the cost of the facility.

In order to overcome this disadvantage, a technique of using an inkjet without a mask has been proposed. Inkjet printing technology is widely developed and developed as a home printer, and if this technology is dedicated to circuit board manufacturing technology, it is possible to expect an effect of increasing the density of mounting parts and reducing the cost by an eco-friendly production process.

As the inkjet method has been proposed, studies on how to implement fine patterns have been progressed gradually, and as a result, a method of curing the ink at the same time as printing by constructing a strong UV system as possible has been proposed.

However, such a method may be an efficient method for an object requiring fineness, such as wiring, but a problem has been proposed that it is not effective for a pad that does not require relatively fineness. This is because the finer the pattern formed at the time of printing, the more number of printings have to be performed to form the pads, and the more problems are caused in print quality, such as the generation of valleys in the pads.

1 is a photograph showing a circuit pattern formed by a circuit board manufacturing method according to the prior art. Referring to FIG. 1, it can be seen that bending (Valley, 1) and separation (Split, 2) occur in the front of the pad.

The ink droplets ejected from the head are hardened by high UV irradiation energy while adhering to the substrate, and as printing is performed several times to form the pads, bending occurs depending on the curing time and difference in the middle of the pads. Defects and surface flatness will also occur.

In addition, due to the characteristics of the ink hardening at the same time as the impact caused a difference in the amount of ultraviolet light is irradiated depending on the location will cause a problem of poor print quality.

The present invention is to provide a circuit board manufacturing method that can solve the printing defect problem by changing the ultraviolet energy in forming the circuit pattern on the substrate using the inkjet technology.

According to an aspect of the present invention, a method for manufacturing a circuit board by forming a circuit pattern including a wiring part and a pad part on one surface of a substrate, by discharging conductive ink on one surface of the substrate, to form a pad pattern corresponding to the pad part. Forming; Temporarily curing the pad pattern; Discharging conductive ink on one surface of the substrate to form a wiring pattern corresponding to the wiring portion; And it can provide a circuit board manufacturing method comprising the step of completely curing the pad pattern and the wiring pattern.

The conductive ink may include a photocurable material, and the temporary curing step may include irradiating ultraviolet rays having a predetermined energy to the pad pattern. At this time, the magnitude of the ultraviolet energy can be adjusted by adjusting the distance from the pad pattern to the light source of the ultraviolet ray.

Full curing of the wiring pattern may be performed by irradiating ultraviolet rays to the conductive ink corresponding to the point of time when the conductive ink is seated on one surface of the substrate, and the forming of the wiring pattern may be performed after the step of forming the pad pattern is completed. Can be performed.

On the other hand, the discharge of the conductive ink can be performed through the inkjet head.

Other aspects, features, and advantages other than those described above will become apparent from the following drawings, claims, and detailed description of the invention.

Hereinafter, a preferred embodiment of a circuit board manufacturing method according to the present invention will be described in detail with reference to the accompanying drawings, in the following description with reference to the accompanying drawings, the same or corresponding components are given the same reference numerals and Duplicate explanations will be omitted.

In the present embodiment, it was intended to apply to the pad formation by using the experimental result that the ultraviolet energy is changed according to the distance between the substrate and the ultraviolet light source. FIG. 2 is a graph showing the intensity of ultraviolet energy according to the distance between the substrate and the ultraviolet light source. Referring to FIG. 2, it can be seen that the farther the distance from the substrate is, the lower the intensity of the ultraviolet energy is. .

With reference to these results, it will be described below a circuit board manufacturing method according to an embodiment of the present invention.

3 is a flow chart showing a circuit board manufacturing method according to an embodiment of the present invention, Figure 4 is a process chart showing a circuit board manufacturing method according to an embodiment of the present invention, Figure 5 is an embodiment of the present invention It is a flowchart which shows the circuit board manufacturing method which followed. 4 and 5, the substrate 10, the inkjet head 20, the ink 22, the pad portion 24, the wiring portion 26, the ultraviolet module 30, and the ultraviolet ray 32 are illustrated. have.

First, the conductive ink 22 is discharged on one surface of the substrate 10 to form a pad pattern corresponding to the pad portion 24 (S10). The pad part 24 is a part of the circuit pattern formed on the circuit board 10 to be electrically connected to an electronic device or the like. The pad part 24 has a relatively larger area than the wiring part 26 which simply transmits an electrical signal. Can have

In order to form the pad part 24, as shown in FIG. 4, a method of discharging the conductive ink 22 using the inkjet head 20 may be used. By using the conductive ink 22 and the inkjet head 20, it is not necessary to perform ancillary processes such as exposure and development, thereby reducing the use of consumables such as masks. In addition, by inputting the position data for the point where the ink 22 is to be discharged so that automatic printing is performed, it is possible to form a pattern more accurately and simply.

Next, the printed pad pattern is temporarily hardened (S20). This is to control the spreadability of the ejected ink 22 in consideration of the fact that the pattern formed on the substrate 10 is also required to be refined according to the recent trend of high integration of the package. That is, to prevent the ink 22 ejected from the substrate 10 from being excessively spread to form the pad pattern.

This process may be carried out through various methods depending on the nature of the ink 22, for example, a method of providing heat for the thermosetting ink 22 may be used, and for the photocurable ink 22 may be used. A method of irradiating light such as ultraviolet ray 32 may be used.

In this embodiment, the method of irradiating the ultraviolet ray 32 to the ejected ink 22 using the photocurable ink 22 is proposed. When the photocurable ink 22 is used, the intensity of the ultraviolet ray 32 irradiated to the ink 22 can be adjusted more easily, and the degree of curing can be effectively controlled. In order to irradiate the ultraviolet light 32 to the ink 22 in this way, as shown in FIG. 4, the ultraviolet module 30 disposed adjacent to the inkjet head 20 may be used. The ultraviolet module 30 may be integrally coupled with the inkjet head 20 or may be separated separately.

Meanwhile, since the pad part 24 occupies a relatively large area compared to the wiring part 26, a method of dualizing the process of forming the wiring part 26 and the process of forming the pad part 24 can be considered. have. That is, the difference between the step of curing the pad pattern and the step of curing the wiring pattern can be efficiently performed. This will be described in more detail as follows.

In the case of the wiring pattern, it is necessary to minimize the spreadability of the ink 22 in accordance with the demand for miniaturization. Therefore, the ejected ink 22 can be cured immediately by irradiating the ultraviolet ray 32 having a strong intensity almost simultaneously with the ejection of the ink 22 so that a fine pattern can be formed.

However, when this method is also applied to the pad pattern, the ejection and curing of the ink 22 must be repeated several times in order to form a relatively large area, which may cause bending and separation as shown in FIG. 1. Will be.

In order to solve this problem, unlike the case of the wiring pattern, the pad pattern, after discharging the ink 22, is irradiated with ultraviolet light 32 having a relatively weak intensity, temporarily cured, and then completely cured later. It is available.

By using such a method, the surface of the ejected ink 22 can be smoothed naturally, thereby reducing the risk of occurrence of the above-described problems.

On the other hand, as a method of adjusting the intensity of the ultraviolet ray 32 provided to the discharged ink 22, a method of adjusting the distance from the pattern to the light source of the ultraviolet ray 32 can be used. Based on the relationship as shown in FIG. 2, the intensity of the ultraviolet ray 32 can be easily adjusted by adjusting the distance from the pattern to the light source. The irradiation of the ultraviolet ray 32 having a relatively low intensity with respect to the ejected ink 22 is shown in FIG. 5 (a), through which the pad pattern in the temporarily hardened state is shown in FIG. 5 (b). Is shown.

Next, the conductive ink 22 is discharged on one surface of the substrate 10 to form a wiring pattern corresponding to the wiring part 26 (S30), and completely cure the pad pattern and the wiring pattern (S40).

As described above, in order to satisfy the demand for miniaturization in the case of the wiring pattern, as shown in FIG. Can be cured. To this end, as described above, a method d ₂ <d ₁ may be used to relatively reduce the distance from the light source to the pattern. In addition, the pad portion 24 may be formed by irradiating and curing a strong ultraviolet ray 32 even on the pad pattern sufficiently flattened through the temporary curing state. The pad pattern and the wiring pattern are formed in this manner is shown in Figure 5 (d).

FIG. 6 is a photograph showing a pad pattern printing result according to ultraviolet ray 32 irradiation energy, and shows a case where the intensity of the ultraviolet ray 32 irradiated from (a) to (d) is small. Referring to FIG. 6, it can be seen that the print quality of the pad is improved as the intensity of the ultraviolet ray 32 irradiated to the pad pattern is smaller.

On the other hand, the above-described formation of the pad pattern and the formation of the wiring pattern may be performed alternately with each other, and after the formation of the pad pattern is completed, the formation of the wiring pattern may be performed. That is, by first providing only the position data corresponding to the pad pattern to the inkjet head 20, the printing of the pad pattern is completed, and then the position pattern corresponding to the wiring pattern is provided to the inkjet head 20 to print the wiring pattern. It is.

In this method, it is not necessary to move the ultraviolet light source until the temporary curing of all the pad patterns is completed, and it is sufficient to move the ultraviolet light source only when the wiring pattern is printed after the printing of the pad pattern is completed. This has the advantage of simplifying the process.

The circuit board manufacturing method according to the embodiment of the present invention has been described above, and many embodiments other than the above-described embodiment are within the claims of the present invention.

As described above, according to the preferred embodiment of the present invention, in forming a circuit pattern on a substrate using inkjet technology, the printing defect problem can be solved by dualizing the curing process for the wiring part and the pad.

Claims (6)

A method of manufacturing a circuit board by forming a circuit pattern including a wiring part and a pad part on one surface of a substrate, Discharging conductive ink on one surface of the substrate to form a pad pattern corresponding to the pad part; Temporarily curing the pad pattern; Discharging the conductive ink on one surface of the substrate to form a wiring pattern corresponding to the wiring part; And And completely curing the pad pattern and the wiring pattern. The method of claim 1, The conductive ink comprises a photocurable material, The temporary curing step, And irradiating ultraviolet rays having a predetermined energy to the pad pattern. The method of claim 2, The magnitude of the energy is controlled by controlling the distance from the pad pattern to the light source of the ultraviolet rays. The method of claim 1, Full hardening of the wiring pattern, Corresponding to the time when the conductive ink is seated on one surface of the substrate, the circuit board manufacturing method, characterized in that performed by irradiating the conductive ink with ultraviolet light. The method of claim 1, Forming the wiring pattern is performed after the forming of the pad pattern is completed. The method of claim 1, And discharging the conductive ink is performed through an inkjet head.

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