KR20160046486A

KR20160046486A - Method for forming circuit pattern of printed circuit board

Info

Publication number: KR20160046486A
Application number: KR1020140142411A
Authority: KR
Inventors: 권건오; 이영종; 임한상
Original assignee: 현대자동차주식회사; 광운대학교 산학협력단
Priority date: 2014-10-21
Filing date: 2014-10-21
Publication date: 2016-04-29

Abstract

The present invention relates to a method for forming a circuit pattern on a printed circuit board, and a method for forming a circuit pattern capable of achieving miniaturization of a printed circuit board having both a large current circuit pattern and a small current circuit pattern, such as a smart junction block There is a main purpose. In order to achieve the above object, there is provided a method of manufacturing a printed circuit board, comprising: providing a printed circuit board on which circuit patterns of the same thickness are formed on a base substrate; Providing a plate with an additional conductor pattern having the same shape and pattern path as a selected one of the circuit patterns; Superimposing the plate on the printed circuit board such that additional conductor patterns are bonded on the selected circuit pattern; And removing the plate to complete a circuit pattern whose thickness is adjusted in a state where an additional conductor pattern is fixed to the selected circuit pattern.

Description

[0001] The present invention relates to a method of forming a circuit pattern on a printed circuit board,

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a circuit pattern forming method of a printed circuit board, and more particularly, to a circuit pattern forming method capable of achieving miniaturization of a printed circuit board having both a large current circuit pattern and a small current circuit pattern, Forming method.

BACKGROUND ART [0002] Conventionally, in a vehicle, a junction box is used for stably supplying and distributing battery power to various electric / electronic devices consuming electricity such as a lamp, a body electric component, a multimedia device, a motor driving device, The box is equipped with a number of fuses to prevent overcurrent or overload from being transmitted to external circuitry and relays to open and close the power supply.

The junction box, which is mainly installed in the engine room of a car, is a kind of distribution box in which each load element, that is, the fuses and relays used for each load are combined in the box between the circuits, And distributes it.

In addition, the junction box functions to store and protect various devices (fuses, relays, etc.) mounted on the inside, to protect wires, and to maintain operating efficiency through rapid heat dissipation.

Meanwhile, Smart Junction Block (Smart Junction Box) (Smart Junction Box, also referred to as Smart Junction Box), which is one step further than the conventional Junction Box, has been developed and applied to vehicles.

The smart junction block is equipped with a printed circuit board (PCB), a fuse, a relay, a switching element, an input / output connector, and a microcontroller.

The smart junction block includes a control unit including a microcontroller and various input / output related elements, and a power unit including a fuse and a large current connector for distributing and supplying battery power.

In the above-mentioned smart junction block, basically, the control unit is connected to other modules in the vehicle such as a BCM (Body Control Module) and a DDM (Driver Door Module) so that CAN communication is possible. For example, And controls the operation of a relay, a switching device, and the like.

Recently, as the number of electric / electronic devices mounted on a vehicle is increasing and the electric current consumption of electric loads in the vehicle is increasing, the size of a smart junction block is also increasing.

On the other hand, since the mounting space of the smart junction block in the vehicle is continuously decreasing, the miniaturization design of the smart junction block is urgently required in order to secure the mounting property.

In order to miniaturize the smart junction block, miniaturization of the PCB is essential. In the smart junction block, the PCB is a component in which the fuses, various devices, and connectors are mounted or assembled, and circuit patterns for electrically connecting them are formed. The size of the PCB is determined by the package area and pattern area of the devices.

Due to the characteristics of the smart junction block that supplies large currents to other devices, the area of the large current circuit and power source for driving large current loads in the PCB is the largest.

Therefore, in order to miniaturize the PCB of the smart junction block, it is very important to reduce the area of the large-current circuit and the large-current patterns of the power supply.

However, the smart junction block has a feature that a common current circuit including a microcontroller and the like exists on the same PCB together with a large current circuit for driving a large current load.

In order to miniaturize a large current PCB, there is a problem that the PCB design of a small current circuit becomes ineffective when a technique such as a metal PCB or a heavy copper PCB commonly used is used.

Since the conventional PCB is manufactured by etching unnecessary parts in the copper foil layer to form a circuit pattern, the thickness of the circuit pattern is set differently for each layer. However, in the same layer, the thickness of the circuit pattern must be made equal.

1 is a view for explaining a conventional PCB manufacturing process in which a patterned copper foil layer 2 is laminated on a base substrate 1 and a dry film 3 is formed on the patterned copper foil layer 2 Laminated.

Then, in order to make the pattern shape, the exposure process for irradiating ultraviolet rays on the working film 4 is carried out. At this time, since the working film 4 can not pass ultraviolet rays, the portion selected in the dry film 3, Ultraviolet rays are irradiated only to the remaining portion except the portion where the pattern is to be formed.

Subsequently, the resist film is immersed in a developing solution to remove a portion irradiated with ultraviolet rays from the dry film (3). Then, the resist film is immersed in an etching solution to selectively remove only the portion of the copper foil layer from which the dry film (3) So that the copper foil layer portions 2a and 2b are left only (etch process).

The residual copper film layer portions 2a and 2b become circuit patterns and the large current patterns 2a and 2b having different widths in manufacturing the PCB of the smart junction block Thereby forming the small current pattern 2b.

When the large current pattern 2a and the small current pattern 2b are formed on the same PCB 10 as described above, the thickness of the pattern must be made uniform by the PCB manufacturing process, The width control method is applied.

In other words, conventionally, the thickness of the large current circuit pattern 2a and the small current circuit pattern 2b have to be made equal, so that the width of the large current circuit pattern is relatively large, So that it is difficult to downsize the PCB 10.

FIG. 2 is a schematic view illustrating a pattern for a large current used in a power source unit in a conventional PCB and a pattern for a small current used in a control unit. The large current pattern 2a and the small current pattern 2b are used in the manufacturing process of FIG. So that the thickness thereof is the same, which adversely affects the downsizing of the PCB 10.

Since the cross-sectional area of the pattern is basically proportional to the square of the current, the circuit pattern for a large current in which a maximum of several ampere flows is designed to have a much larger cross-sectional area than a circuit pattern for a small current flowing several tens of mA.

Controls include small packaged devices such as BGAs, and to minimize the PCB design of small packaged devices, their pattern width must be reduced and the spacing between the patterns must be tightly designed.

However, if the thickness of the pattern in the control part is increased, the width and spacing of the designable pattern are increased, which makes it difficult or impossible to design the control part. If the thickness of the pattern is not increased, the width of the high- It is difficult to miniaturize the power supply unit.

Among these technologies, embedded PCBs, embedded copper PCBs, and metal PCB technologies, among which embedded PCBs are techniques for reducing PCB area due to element area by inserting active or passive elements into the PCB inner layer, Does not include a passive element that can be inserted into the inner layer of the PCB, so its effect is limited in the smart junction block.

In addition, the PCB area of the power supply PCB can be reduced by increasing the thickness of the pattern, while reducing the width of the pattern while maintaining the same cross-sectional area. However, as the pattern thickness increases, The miniaturization of the control unit using the small package of FIG.

Metal PCB is a technology for designing a large current PCB by using a metal having good heat transfer characteristics as a core or a base substrate. It is effective for miniaturization of a power supply unit. However, the insulation of the vias, etc., has a negative influence on the PCB design of the control part.

Thus, in order to generate a pattern for a large current and a pattern for a small current, the cross-sectional area of the pattern required according to the current capacity is secured by adjusting the width in a state where the thickness is fixed. In the case of a PCB having only one characteristic of a large current or a small current because the thickness is the same, it is suitable for a PCB of a smart junction block having both characteristics. However, it has disadvantages such as sacrificing one of the miniaturization characteristics, .

SUMMARY OF THE INVENTION Accordingly, it is an object of the present invention to provide a circuit pattern forming method capable of achieving miniaturization of a printed circuit board having both a large current circuit pattern and a small current circuit pattern as in a smart junction block The purpose is to provide.

According to an aspect of the present invention, there is provided a method of manufacturing a printed circuit board, the method including: providing a printed circuit board on which circuit patterns of the same thickness are formed on a base substrate; Providing a plate with an additional conductor pattern having the same shape and pattern path as a selected one of the circuit patterns; Superimposing the plate on the printed circuit board such that additional conductor patterns are bonded on the selected circuit pattern; And removing the plate to complete a circuit pattern whose thickness is adjusted in a state where an additional conductor pattern is fixed to the selected circuit pattern.

According to the method of forming a circuit pattern on a printed circuit board according to the present invention, by applying a method of forming a thickness of each pattern on a printed circuit board of a smart junction block according to a required current capacity, Can be minimized, and it is possible to miniaturize the power supply circuit, the PCB, and the smart junction block.

1 is a view showing a method of forming a circuit pattern of a printed circuit board according to the prior art.
2 is a schematic view illustrating a pattern for a large current used in a power source unit and a pattern for a small current used in a control unit in a conventional printed circuit board.
3 is a schematic view illustrating a circuit pattern for a large current and a circuit pattern for a small current formed according to the present invention.
4 is a view showing a circuit pattern forming method of a printed circuit board according to the present invention.
5 is a cross-sectional view of a PCB on which a pattern is formed according to the present invention.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings, which will be readily apparent to those skilled in the art to which the present invention pertains.

The present invention relates to a circuit pattern forming method capable of downsizing a printed circuit pattern having both a large current circuit pattern and a small current circuit pattern, such as a printed circuit board of a smart junction block for a vehicle, In order to secure a cross-sectional area of a desired pattern, a method of controlling the thickness of the pattern instead of the method of controlling the pattern width according to the large current and the small current is employed.

3 is a schematic view illustrating a circuit pattern for a large current and a circuit pattern for a small current formed according to the present invention. As shown in the figure, in a printed circuit board (hereinafter referred to as PCB) 10 of a smart junction block, In forming the large current pattern 12 used in the circuit and the small current pattern 13 used in the control circuit, the thickness is differentiated to form a pattern.

According to the circuit pattern forming method of the present invention, it is possible to downsize the large current circuit such as the power supply unit without affecting the small current circuit of the control unit or the like, The miniaturization of the smart junction block becomes possible.

The width of the large current pattern 12 and the width of the small current pattern 13 can be made equal to each other or the width of the large current pattern 12 and the width of the small current pattern 13 ) Can be made different.

However, in order to secure the cross-sectional area of the pattern corresponding to the current capacity, the thickness of the large current pattern 12 is made larger than the thickness of the small current pattern 13 to form each pattern.

At this time, the pattern 12a for a large current and the pattern 13 for a small current are formed on the base substrate 11 with the same thickness, and then the pattern cross sectional area according to the current capacity required in the large current pattern 12a is secured The thickness of the entire large current pattern 12 is made larger than the thickness of the small current pattern 13 by further laminating the conductor pattern 12b on the large current pattern 12a formed for the first time.

Since the thickness of the large current pattern 12 can be determined independently of the thickness of the small current pattern 13, it is possible to simultaneously miniaturize the power supply part and the control part of the smart junction block.

FIG. 4 is a view illustrating a method of forming a circuit pattern of a PCB according to the present invention. Referring to FIG. 1, before the process of FIG. 4 is performed, The pattern 12a and the small current pattern 13 are formed primarily.

In this case, it is possible to form the pattern by making the width of the pattern 12a for the first large current and the width of the pattern 13 for the small current different or different. FIG. 4 is a cross- An example is shown.

1, each of the patterns is formed to have a thickness suitable for the pattern 13 for the small current.

That is, since the large current pattern 12a and the small current pattern 13 are formed to have the same thickness only by the primary circuit pattern forming process in which the base substrate 11 is processed, the small current pattern 13 ), And thereafter, an additional pattern stacking process is performed to meet the thickness of the large current pattern 12a.

FIG. 4 shows only an additional process for meeting the thickness of the final large current pattern using a PCB having undergone the primary circuit pattern forming process. In the illustrated additional process, the large current pattern (Hereinafter referred to as " additional conductor pattern ") 13 is laminated on the first large current pattern 12a (hereinafter referred to as a first large current pattern) 12a to complete the large current pattern 12 finally meeting the required thickness do.

Referring to FIG. 4, a PCB having only a primary pattern forming process is prepared (see FIG. 4A), and an additional conductive pattern having the same width and the same shape and path as the pattern 12a for primary large current 12b are attached (see Fig. 4 (b)).

At this time, the additional conductor pattern 12b should be prepared in a state in which the additional conductor pattern 12b is temporarily attached to the plate 20 (in a joined state), and in a state where an additional conductor pattern 12b is laminated on the pattern 12a for the first large current Only the plate 20 should be prepared to be removed from the PCB.

As an example of the process of preparing the plate 20 to which the additional conductor pattern 12b is temporarily attached, an additional conductor pattern 12b is formed on the plate 20, 12b are formed by sequentially performing a copper foil layer forming step, a dry film laminating step, an exposure step using a working film and an ultraviolet light source, a developing step, an etching step and a peeling step in the same manner as in the primary circuit pattern forming step.

However, before the copper foil layer is formed, the additional conductor pattern 12b must be temporarily bonded to the plate 20, that is, in a state in which the plate can be easily removed in the desorption process. A copper foil layer is formed on the bonding layer, and then the dry film laminating process, the exposure process, the developing process, the etching process, and the peeling process are performed do.

For example, the bonding layer may be formed by applying a material that is denatured or removed by heat to facilitate pattern peeling.

Next, the plate 20 is stacked on the PCB (Fig. 4 (c) and Fig. 4 (d)) so that the additional conductor pattern 12b is bonded to the primary large current pattern 12a using a jig (See Fig. 4 (e)), and the plate 20 is removed by performing a further desorption process such as a heating process.

As a result, the large current pattern 12 of the final PCB is completed with the first large current pattern 12a and the additional conductor pattern 12b being joined and fixed. The first large current pattern 12a and the additional conductor pattern 12b 12b may be achieved by a method of bonding the two patterns using soldering when the PCB 20 having been subjected to the primary circuit pattern forming process is coupled with the plate 20, A method of processing a through hole and then filling the conductive material 14 inside the through hole is applicable.

When the terminal pin of the device such as a connector or a fuse is connected to the large current pattern 12, a through hole which passes through the both side patterns at the same time is formed and then the terminal pin is inserted into the through hole to solder the two patterns. So that it can be fixed in one piece.

As described above, according to the present invention, the circuit pattern of the power supply unit in the smart junction block, that is, the final thickness of the large current pattern, is compared with the circuit pattern of the control unit, that is, The pattern area occupied by the large current pattern can be reduced.

In other words, by applying a method of forming the thickness of each pattern according to the required current capacity, the pattern area on the PCB can be minimized for the same pattern length, and the miniaturization of the power supply circuit, the PCB, and the smart junction block It becomes possible.

5 is a cross-sectional view of a PCB on which a pattern is formed according to the present invention. The process of forming additional conductive patterns as shown in FIG. 4 is repeatedly performed for the same pattern for the first large current (the same thickness as the pattern for small current) It is possible to form a final high current pattern having a thickness.

Further, as shown in Fig. 5, the widths of the respective patterns can be different, and when forming a plurality of patterns, the thicknesses of the patterns may be different from each other.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the scope of the present invention is not limited to the disclosed exemplary embodiments. Forms are also included within the scope of the present invention.

10: printed circuit board (PCB) 11: base board
12: large current pattern 12a: primary large current pattern
12b: additional conductor pattern 13: pattern for small current

Claims

Providing a printed circuit board on which circuit patterns of the same thickness are formed on a base substrate;
Providing a plate with an additional conductor pattern having the same shape and pattern path as a selected one of the circuit patterns;
Superimposing the plate on the printed circuit board such that additional conductor patterns are bonded on the selected circuit pattern; And
And removing the plate to complete a circuit pattern whose thickness is adjusted in a state where an additional conductor pattern is fixed to the selected circuit pattern.

The method according to claim 1,
Wherein the printed circuit board includes:
Forming a copper foil layer for pattern on the base substrate;
Laminating a dry film on the patterned copper foil layer;
Exposing a portion of the dry film other than a portion where a circuit pattern is to be formed;
Developing and removing the exposed portions of the dry film;
Etching and removing the copper foil layer where the dry film is removed; And
And then peeling off the dry film to form a circuit pattern on the printed circuit board.

The method according to claim 1,
Wherein the selected circuit pattern and the additional conductor pattern are fixed by soldering and bonding the two patterns when the plate and the printed circuit board are coupled to each other.

The method according to claim 1,
Wherein the selected circuit pattern and the additional conductor pattern are formed by processing a through hole through which both patterns are simultaneously passed after removing the plate, and then filling and fixing the conductive material inside the through hole.

The method according to claim 1,
The circuit pattern and the additional conductor pattern are fixed by brazing when the through holes are formed in the both side patterns after the plate is removed and then the terminal pins of the connector or the element are inserted into the through hole for connection of the connector or element and soldered thereto Wherein the circuit pattern is formed on the printed circuit board.

The method according to claim 1,
The plate to which the additional conductor pattern is attached,
Forming a bonding layer on the plate, which is denatured or removed by heat in a desorption process for removing the plate to enable pattern separation;
Stacking a copper foil layer on the bonding layer;
Laminating a dry film on the patterned copper foil layer;
Exposing a portion of the dry film other than a portion where a circuit pattern is to be formed;
Developing and removing the exposed portions of the dry film;
Etching and removing the copper foil layer where the dry film is removed; And
And then peeling off the dry film to form a circuit pattern on the printed circuit board.