KR100782404B1 - Printed circuit board and manufacturing method thereof - Google Patents

Abstract

A printed circuit board and a manufacturing method thereof are provided to improve the conductivity between substrates by forming a plating layer on the surface of a paste bump. A method for manufacturing a printed circuit board includes the steps of: forming a paste bump by selectively printing a conductive paste on a substrate(S10); forming a plating layer on the surface of the paste bump(S20); and stacking an insulating material on the substrate to make the paste bump penetrate the insulating material(S30). An inner layer circuit is formed on the surface of the substrate. The first step includes the step of printing the conductive paste to be elastically connected to the inner layer circuit.

Description

Printed circuit board and manufacturing method thereof

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

2 is a flowchart illustrating a manufacturing process of a printed circuit board according to an exemplary embodiment of the present invention.

Figure 3 is a cross-sectional view showing a printed circuit board according to an embodiment of the present invention.

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

100: substrate 103: inner layer circuit

105: paste bump 107: plating layer

109: insulating material 111: metal layer

113: outer layer circuit

The present invention relates to a printed circuit board and a method of manufacturing the same.

Functions of various electronic devices such as mobile phones are increasing, but the market demands smaller size. Accordingly, the circuit density of the printed circuit board gradually increases, and the process cost for manufacturing the same increases. Among them, a costly process is a process for connecting circuit layers in a multilayer printed circuit board having multilayer circuit pattern layers.

In a printed circuit board, a method of interlayer connection is used to process a through hole using a laser drill or a mechanical drill and then plate the inner wall of the through hole, or to fill the through hole by plating. However, the process of drilling through-holes increases the cost of printed circuit boards, lowers the production rate, and the method of drilling and plating through-holes increases the manufacturing cost as the number of interlayer connections increases. May occur.

In addition, a method of electrically conducting the through hole by filling a conductive paste into the through hole is also used. However, when the diameter of the through hole is small, it is difficult to fill the through hole by printing a uniform conductive paste. Problems can arise with reliable connection.

Therefore, there is a need for a more improved interlayer connection method capable of smoothly implementing interlayer connection of a multilayer printed circuit board without a process of drilling a through hole.

The present invention provides a printed circuit board and a method for manufacturing the same, which can improve conductivity between substrate layers and can reduce resistance due to high conductivity of the surface as the substrate is used at high frequencies.

According to one aspect of the invention, (a) selectively printing a conductive paste on a substrate to form a paste bump, (b) forming a plating layer on the surface of the paste bump, (c) the paste bump is an insulating material Provided is a method for manufacturing a printed circuit board, the method including laminating an insulating material to a substrate to penetrate through the substrate.

By forming the plating layer on the surface of the paste bump, it is possible to implement high conductivity between the layers of the substrate using the plating layer, it is possible to improve the conductivity up to a high frequency region.

An inner layer circuit is formed on a surface of the substrate, and step (a) may include printing a conductive paste to be electrically connected to the inner layer circuit.

Step (b) may be performed by any one or more methods selected from the group consisting of electroless plating, electrolytic plating and sputtering.

After step (c), it is preferable to further include the step of (d) laminating a metal layer on the surface of the insulating material to pressurize the paste bumps and selectively remove the metal layer to form an outer layer circuit electrically connected to the paste bumps. .

After step (d), (e) selectively printing a conductive paste on an insulating material on which an outer layer circuit is formed to form an outer layer bump, (f) forming a plating layer on the surface of the outer layer bump, and (g) The method may further include stacking the buildup layer on the insulating material such that the outer bump penetrates the buildup layer.

It is preferable that the thickness of a plating layer is 0.5 micrometer-10 micrometers.

According to another aspect of the invention, a printing comprising a substrate, a paste bump selectively printed on the surface of the substrate, a plating layer formed on the surface of the paste bump, and an insulating layer laminated on the substrate and penetrated by the paste bump A circuit board is provided.

An inner layer circuit is formed on the surface of the substrate, and the paste bump is preferably printed to be electrically connected to the inner layer circuit.

The plating layer may be formed by any one or more methods selected from the group consisting of an electroless plating method, an electrolytic plating method, and sputtering.

It is preferable to further include an outer layer circuit formed on the surface of the insulating material and electrically connected to the paste bumps.

Other aspects, features, and advantages other than the foregoing will be apparent from the following detailed description of the invention including the drawings and the claims.

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

1 is a flowchart illustrating a method of manufacturing a printed circuit board according to an exemplary embodiment of the present invention.

In the present embodiment, in the method of electrical connection between circuit layers during the manufacturing process of a multilayer printed circuit board, an interconnect bump is formed by using a conductive paste, and a metal layer is plated on the surface of the paste bump to improve interlayer conductivity of the substrate. It is characterized in that.

To this end, first, an inner layer circuit is formed on the surface of the substrate. The inner layer circuit can be formed by applying a subtractive method to a substrate on which a metal layer such as a copper clad laminate (CCL) is laminated, or a substrate on which an metal layer is formed on an insulating substrate by electroless plating or the like. Thus, the paste bump is printed on the substrate on which the inner layer circuit is formed (S10). The metal layer used as a material of an inner layer circuit can be made into a suitable material according to manufacturing conditions, such as copper, silver, and aluminum.

Since the paste bumps serve as a passage for conducting the circuit layers as described below, it is preferable to print the paste bumps so as to be electrically connected to the inner layer circuits (S12). That is, paste bumps are formed at positions where interlayer connection is required among the inner layer circuits.

Next, a plating layer is formed on the surface of the paste bumps (S20). The plating layer may be formed by an appropriate method in consideration of the material and process conditions of the paste bumps such as electroless plating, electrolytic plating or sputtering, and may be plated by applying various methods in combination.

Here, sputtering is a technique of attaching to the surface of a target in the form of a film, in which a thin film or a thick film is formed by evaporating a solid in a high vacuum state in order to make an electronic circuit, such as a ceramic or a material. Is used in the case.

More specifically, by plating the surface of the paste bumps, it is possible to improve the electrical conductivity of the interlayer connection through the paste bumps, since the resistance decreases as the electrical conductivity of the circuit is improved, so that the substrate is used in the high frequency region. It is possible to manufacture a printed circuit board that can function more effectively.

The plating layer not only improves the electrical conductivity of the substrate, but also serves to structurally reinforce the shape of the paste bumps in the pressing process of the paste bumps, which will be described later. It can be designed accordingly. For example, it can be in the range of 0.5 micrometer-10 micrometers.

The material of the plating layer may be a material having high conductivity such as copper, gold, silver, platinum, nickel, iron, and structurally supporting the paste bumps. These plating materials may be attached to the surface of the paste bump to serve to improve electrical conductivity and structural rigidity.

After forming the plating layer on the surface of the paste bump, the insulating material is laminated on the substrate so that the paste bump penetrates the insulating material (S30). Polypropylene glycol or an insulating film may be used as the insulating material, and a roll laminator or a press may be used to stack the insulating material so that the paste bump penetrates the insulating material. In this process, it is of course possible to use a dedicated laminate used in so-called buried bump interconnection technology (B2it), which prints paste bumps on a substrate to achieve interlayer interconnection.

Next, a metal layer is laminated on the surface of the insulating material so that one circuit layer is further formed. In this process, the surface of the insulating material is flattened by pressing the paste bump partially protruding from the surface of the insulating material (S40). Accordingly, as in the stacking of the insulating material, a metal layer is laminated on the surface of the insulating material by using a press machine or a laminator, and an outer layer circuit which is electrically connected between layers by paste bumps can be implemented.

As in the case of forming the inner layer circuit, the outer layer circuit is formed by applying a circuit pattern forming process such as a subtractive method to the metal layer laminated on the surface of the insulating material. The portion of the outer layer circuit to which the electrical connection between layers with the inner layer circuit is to be implemented is electrically connected to the paste bump so that the paste bump according to the present embodiment serves as an electrical passage between the circuit layers (S50).

In this manner, the inner layer circuit and the outer layer circuit can be electrically conducted by using paste bumps having surface plating. According to the present exemplary embodiment, a multilayer printed circuit board having two or more layers may be manufactured by stacking a plurality of substrates having a paste bump having a plating layer formed on the surface thereof.

That is, the conductive paste is printed on the insulating material on which the outer layer circuit is formed to form the outer layer bump, that is, the paste bump. The outer bumps must be formed at positions electrically connected to the outer circuits as in the case of the paste bumps and the inner circuits described above.

A plating layer is formed on the surface of the outer bump as in the case of the paste bump described above, and a buildup layer which is an insulating material is laminated so that the outer bump passes through the buildup layer. The process of laminating a metal layer on the surface of the build-up layer to press the outer bump and selectively removing the metal layer to form a circuit pattern is similar to the above-described outer layer circuit forming process.

Build-up is continued in this manner to form a multilayer printed circuit board. After the lamination process or lamination of the multi-layered circuit pattern layer, post-processing such as drilling, copper plating, resist coating, surface treatment, and routing may be performed.

2 is a flowchart illustrating a manufacturing process of a printed circuit board according to an exemplary embodiment of the present invention, and FIG. 3 is a cross-sectional view illustrating a printed circuit board according to an exemplary embodiment of the present invention. 2 and 3, a substrate 100, an inner layer circuit 103, a paste bump 105, a plating layer 107, an insulating material 109, a metal layer 111, and an outer layer circuit 113 are illustrated. .

As shown in FIG. 2A, the paste bump 105 is formed by printing a conductive paste on the surface of the insulating substrate 100 on which metal foils such as copper, silver and aluminum are laminated to form the inner layer circuit 103 on the surface. Form. In this case, it is preferable to print the conductive paste so as to be electrically connected to the inner layer circuit 103 formed on the surface of the substrate 100.

As shown in FIG. 2B, after the conductive paste is printed to be electrically connected to the inner layer circuit 103 formed on the surface of the substrate 100, the surface of the paste bump 105 is plated to form the plating layer 107. do.

More specifically, by plating the surface of the paste bump 105 to form the plating layer 107, it is possible to improve the electrical conductivity of the substrate 100, in particular, when the substrate 100 is used in a high frequency region, the paste bump Since the resistance of the substrate decreases as the conductivity of the surface of the substrate increases, a printed circuit board that realizes more efficient electrical conduction can be manufactured.

The plating layer 107 may be formed by a suitable method such as electroless plating, electroplating, or sputtering as described above, and the material may be copper, gold, silver, platinum, nickel, iron, or the like. The thickness of the plating layer 107 is within the range of improving the conductivity of the substrate 100 by the paste bump 105 and preventing the shape of the paste bump 105 from being deformed more than necessary in the pressing process of the paste bump 105. It is preferable to set at, and may be, for example, 0.5 μm to 10 μm.

As shown in FIG. 2C, the substrate 100 is provided with the insulating material 109 so that the paste bump 105 penetrates the insulating material 109 on the substrate 100 having the plating layer 107 formed on the surface of the paste bump 105. )). In this case, the insulating material 109 may use polypropylene glycol or an insulating film, and the insulating material 109 is laminated on the substrate 100 using a roll laminator or a press.

As shown in FIG. 2D, the metal layer 111 is aligned on the insulating material 109, and as shown in FIG. 2E, the metal layer 111 is laminated on the surface of the insulating material 109 to paste the paste 105. Pressurize. At this time, the shape of the paste bump 105 is deformed so that the surface of the insulating material is flat as shown.

In FIG. 2F, the outer layer circuit 113 electrically connected to the paste bump 105 is formed by selectively removing the metal layer 111. The outer circuit 113 may be formed to be electrically connected to the paste bump 105 as in the inner circuit 103.

In addition, in the present embodiment, as shown in FIG. 2 (f), the paste bumps are formed to be electrically connected to the outer layer circuits, and the insulating material is built up again to manufacture a multilayer printed circuit board. In this process, if necessary, the substrate 100 may be removed to expose the circuit pattern on both sides of the multilayer printed circuit board.

Accordingly, as shown in FIG. 2G, the paste bump 105 is printed, the plating layer 107 is formed on the surface thereof, and then the process of building up the insulating material is repeatedly performed, thereby forming a multilayer printed circuit board having a plurality of circuit layers. To prepare. In this way, the electrical connection between the circuit layers is formed without the use of a laser or a mechanical drill, and the paste bumps 105 are formed and then the surface is plated to smoothly implement the interlayer connection without the process of drilling through holes. Can improve.

3 is a cross-sectional view of the multilayer printed circuit board manufactured according to the above method. After the two or more circuit layers are laminated in this manner, a printed circuit board may be completed by performing post-processing such as drilling, copper plating, resist coating, surface treatment, and routing.

Many embodiments other than those described above are within the scope of the present invention.

As described above, a printed circuit board and a method of manufacturing the same according to an exemplary embodiment of the present invention may form a plating layer on a surface of a paste bump connecting the layers of the substrate, thereby improving conductivity between layers of the substrate using the plating layer. In addition, as the substrate is used at a high frequency, the resistance may be reduced by the high conductivity of the surface.

Claims (10)

(a) selectively printing a conductive paste on the substrate to form a paste bump; (b) forming a plating layer on a surface of the paste bump; And (c) stacking the insulating material on the substrate such that the paste bump penetrates the insulating material. The method of claim 1, An inner layer circuit is formed on a surface of the substrate, and the step (a) includes the step of printing the conductive paste to be electrically connected to the inner layer circuit. The method of claim 1, The step (b) is a method for manufacturing a printed circuit board, characterized in that carried out by any one or more methods selected from the group consisting of electroless plating, electroplating and sputtering. The method of claim 1, After step (c), (d) stacking a metal layer on the surface of the insulating material to pressurize the paste bump and selectively remove the metal layer to form an outer circuit electrically connected to the paste bump. The method of claim 4, wherein After step (d) above, (e) selectively printing a conductive paste on the insulating material on which the outer layer circuit is formed to form an outer layer bump; (f) forming a plating layer on a surface of the outer bump; And and (g) stacking the buildup layer on the insulating material such that the outer bump passes through the buildup layer. The method of claim 1, The thickness of the plating layer is a printed circuit board manufacturing method, characterized in that 0.5㎛ to 10㎛. A substrate; Paste bumps selectively printed on a surface of the substrate; A plating layer formed on a surface of the paste bump; A printed circuit board stacked on the substrate, the printed circuit board including an insulating layer penetrated by the paste bump. The method of claim 7, wherein A printed circuit board, wherein an inner layer circuit is formed on a surface of the substrate, and the paste bump is printed to be electrically connected to the inner layer circuit. The method of claim 7, wherein The plating layer is a printed circuit board, characterized in that formed by any one or more methods selected from the group consisting of electroless plating, electroplating and sputtering. The method of claim 7, wherein The printed circuit board further comprises an outer layer circuit formed on a surface of the insulating material and electrically connected to the paste bump.

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