KR20090099334A - Printed circuit board and manufacturing method thereof - Google Patents

Abstract

A printed circuit board and a manufacturing method thereof are provided to secure high reliability of electric connection regardless of physical impact by integrating a blind via and a via land. A printed circuit board includes a core substrate(10), a blind via(12), a copper foil(14), a via land(16), a connection unit(18), and a solder ball pad(20). The blind via is formed in one side of the core substrate. An opening is formed in a blind via to one direction of the core substrate. The copper coil is formed in the other side of the core substrate to contact with the blind via. The via land is stacked on the copper foil. The connection unit passes through the copper foil and integrates the blind via and the via land. The solder ball pad contacts with the via land. The solder ball pad is made of nickel and gold.

Description

Printed Circuit Board and Manufacturing Method Thereof

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

According to the prior art, the through-holes were drilled using a drill to form an interlayer through via, and copper plating was performed, and the inside of the through-holes was filled using a resin or the like. Thereafter, unnecessary resin was removed by polishing to smooth the surface, and then copper plating was performed again to form an interlayer conductive via.

However, when the via is processed using a drill, since the filler is filled in the through-hole and polishing is performed using buffing or the like, there is difficulty in manufacturing control due to stretching of the substrate. In addition, since the cap copper plating is performed, it is affected by polishing variation and copper plating variation, so it is not suitable for forming a fine circuit pattern, and there is a problem that polishing is not possible when the substrate is thin.

Therefore, there is a problem in that the via formation method using the drill process cannot cope with the trend of miniaturization and thinning of the substrate size and miniaturization of the circuit pattern.

Accordingly, a method of interlayer conduction with a blind via structure through a laser processing method was used. However, when comparing vias with lasers and vias with drills, the vias are formed using lasers and products made with VOP (Via On Pad) structures are more vulnerable to physical impact. have.

1 is a cross-sectional view illustrating a blind via of a printed circuit board according to a conventional laser processing technology. Referring to FIG. 1, a core substrate 1, a blind via 2, a copper foil 4, a via land 6, a solder ball pad 8, and a solder resist 9 are shown.

According to the prior art by laser processing, since the copper foil 4 and the blind via 2 were connected between layers by connection, the interface existed between the copper foil 4 and the blind via 2. If cracks and lifts due to external impacts occur at the interface between the copper foil 4 and the blind via 2, the connection between the copper foil and the blind via is not complete. Therefore, the resistance of the via is increased and the reliability of the electrical connection is deteriorated. there was.

The present invention provides a printed circuit board having excellent reliability of electrical connection through a laser processing method according to the trend of miniaturization and thinning of the package substrate by reducing the interface between the copper foil and the blind via generated during the via formation by laser processing. To provide.

According to an aspect of the present invention, a blind via is formed on the core substrate and the core substrate, and the via is formed in one direction of the core substrate, and the copper foil and copper foil are formed on the other surface of the core substrate at the position where the blind via is formed. Provided is a printed circuit board having a via land integrally connected to each other and a connection part penetrating through copper foil and integrally connecting the blind via and the via land.

Here, the blind via, the via land and the connecting portion can be integrally formed by performing copper plating.

The printed circuit board may further include a solder ball pad formed in contact with the via land, and the solder ball pad may be formed of a material including nickel (Ni) and gold (Au).

In addition, according to another aspect of the invention, providing a copper foil laminated plate laminated copper foil on both sides of the core substrate, forming a blind via hole from one surface of the copper foil laminated plate, the connection hole connected to the blind via hole on the other surface of the copper foil laminate A method of manufacturing a printed circuit board is provided, the method comprising: forming a copper plating layer on both sides, forming a copper plating layer on an inner wall of a blind via hole, and a connection hole, and forming a circuit pattern and a via land on a core substrate.

Here, the step of forming a solder ball pad formed in contact with the via land may be further performed. The solder ball pads may be formed by plating nickel (Ni) and gold (Au) at positions where the solder ball pads are formed.

Here, the forming of the blind via hole may be performed by etching the copper foil on one surface of the copper foil laminate at the position where the blind via hole is formed, and etching the core substrate into the shape of the blind via hole through laser processing.

The step of forming the connection hole described above may be performed by drilling the copper foil on the other surface of the copper foil laminate through a laser processing process or an etching process.

Meanwhile, the forming of the copper plating layer may include forming roughness on both sides of the copper foil laminate, inside walls of the blind via holes, and the connection holes, and forming a seed layer on both sides of the copper foil laminate, inside the blind via holes, and the connection holes through electroless plating. The electrolytic copper plating may be performed on the seed layer.

In addition, the forming of the circuit pattern and the via land on the core substrate may be performed by forming an etching resist on the copper plating layer, supplying an etching solution to the copper plating layer, and removing the etching resist.

According to the exemplary embodiment of the present invention, since the blind via and the via land of the printed circuit board are integrally connected, it is possible to secure excellent electrical connection reliability even in physical impact.

As the invention allows for various changes and numerous embodiments, particular embodiments will be illustrated in the drawings and described in detail in the written description. However, this is not intended to limit the present invention to specific embodiments, it should be understood to include all transformations, equivalents, and substitutes included in the spirit and scope of the present invention. In the following description of the present invention, if it is determined that the detailed description of the related known technology may obscure the gist of the present invention, the detailed description thereof will be omitted.

The terminology used herein is for the purpose of describing particular example embodiments only and is not intended to be limiting of the present invention. Singular expressions include plural expressions unless the context clearly indicates otherwise. In this application, the terms "comprise" or "have" are intended to indicate that there is a feature, number, step, operation, component, part, or combination thereof described in the specification, and one or more other features. It is to be understood that the present invention does not exclude the possibility of the presence or the addition of numbers, steps, operations, components, components, or a combination thereof.

Hereinafter, an 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 following description with reference to the accompanying drawings, the same or corresponding components are given the same reference numerals. Duplicate explanations will be omitted.

2 is a cross-sectional view illustrating a blind via of a printed circuit board according to an exemplary embodiment of the present invention. Referring to FIG. 2, a core substrate 10, a blind via 12, a copper foil 14, a via land 16, a connection portion 18, a solder ball pad 20, and a solder resist 22 are shown.

According to one embodiment of the present invention, a blind via 12 is formed on one surface of the core substrate 10 to electrically connect the upper and lower surfaces of the substrate. The blind via 12 is formed in the core substrate such that the opening 42 of the blind via is formed in one direction of the core substrate. The blind via 12 serves to electrically conduct the upper and lower surfaces of the core substrate 10.

The core substrate 10 is a substrate in which the interlayer conduction is performed by the blind via 12. In the present embodiment, the core substrate 10 is illustrated as a single layer substrate, but a multilayer substrate requiring interlayer conduction will also be included in the core substrate 10 referred to in the present invention. .

Moreover, the copper foil 14 which contact | connects a blind via is formed in the other surface of the core board | substrate 10 in the position where the blind via 12 was formed. In other words, the copper foil 14 in contact with the blind via is formed on the other surface of the core substrate 10 through which the blind via 12 penetrates.

As shown in FIG. 2, via lands 16 integrally connected to the blind vias 12 are stacked on the copper foil 14 on the other surface of the core substrate 10.

In the present description, the copper foil 14 refers to a copper foil layer formed on both sides of a commercially available copper foil laminate plate laminated on both sides of the core substrate 10, and the circuit patterns and the via lands 16 of the printed circuit board are formed in the electrolytic plating process. Serves as a base layer that can be.

In the present embodiment, the via land 16 is integrally formed at the same time when the blind via 12 is formed, unlike the prior art. Therefore, as shown in FIG. 2, the blind via 12 and the via land 16 are integrally connected through the connection unit 18.

Here, as shown in FIG. 2, the connection part 18 penetrates through the copper foil 14 on the other surface of the core substrate 10 and serves to integrally connect the blind via 12 and the via land 16.

According to one embodiment of the invention, the blind via 12, via land 16 and the connecting portion 18 is formed integrally as shown in Figure 2 by performing copper plating. Therefore, the area of the interface between the blind via 12 and the copper foil 14 which existed in the prior art is reduced. This reduces the likelihood of cracking at the interface between the blind via and the copper foil during external impact. In addition, since the blind via 12 and the via land 16 are integrally connected, cracks are reduced in the joint surface between the blind via 12, the copper foil 14, and the via land 16 during an external impact.

According to this embodiment, the reliability of the electrical connection is maintained as long as there is no crack in the connecting portion 18 connecting between the blind via 12 and the via land 16.

The solder ball pad 20 formed in contact with the via land 16 and formed of nickel (Ni) and gold (Au) and solder resists 22 formed on both surfaces of the core substrate 10 are further provided to resist external impact. And it can provide a printed circuit board of VOP (Via On Pad) structure with excellent electrical reliability.

3 is a flowchart illustrating a method of manufacturing a printed circuit board according to an embodiment of the present invention, and FIGS. 4 to 15 are flowcharts illustrating a method of manufacturing a printed circuit board according to an embodiment of the present invention. 4 to 15, the core substrate 10, the blind via 12, the blind via hole 13, the copper foil 14, the via land 16, the connecting portion 18, the solder ball pad 20, Solder resist 22, copper foil laminate 30, connection hole 32, seed layer 34, copper plating layer 36, etching resist 38, circuit pattern 40, openings of blind vias 42 Is shown.

In the present description, the blind via hole 13 refers to a processing hole in which one side is opened as a step before performing the interlayer conduction of the substrate, and the blind via 12 is copper plated on the inner wall of the blind via hole 13. Interlayer means through vias.

Hereinafter, a method of manufacturing a printed circuit board according to an exemplary embodiment of the present invention illustrated in FIG. 3 will be described according to the flow of the manufacturing process illustrated in FIGS. 4 to 5.

First, as shown in FIG. 4, a copper foil laminate 30 having copper foils 14 stacked on both surfaces of the core substrate 10 is provided (S100).

Then, blind via holes 13 are formed from one surface of the copper foil laminate 30 as shown in FIGS. 5 and 6 (S200).

According to the exemplary embodiment of the present invention, in order to form the blind via hole 13 on one surface of the copper foil laminated plate 30, the copper foil 14 on one surface of the copper foil laminated plate 30 is formed at the position where the blind via hole 13 is formed. It is removed by etching (S210).

6, the core substrate 10 is etched into a shape corresponding to the blind via hole 13 through laser processing (S220). By irradiating a laser to one surface of the core substrate 10 from which the copper foil 14 is removed, a blind via hole 13 having one side open as shown in FIG. 6 can be formed.

Then, as shown in FIG. 7, a connection hole 32 connected to the blind via hole 13 is formed on the other surface of the copper foil laminate 30 (S300). According to this embodiment, the copper foil 14 formed in the other surface of the copper foil laminated board 30 can be drilled through a laser processing or an etching process.

 For example, the connection hole 32 connected to the blind via hole 13 may be formed by performing laser processing on the other surface of the copper foil laminate 30 at the position of the blind via hole 13. Alternatively, the connection hole 32 may be formed by forming an etching resist having a pattern of the connection hole 32 to be formed on the other surface of the core substrate 10 and supplying an etching solution to the other surface of the core substrate 10.

Next, as shown in FIGS. 8 to 10, the copper plating layer 36 is formed on both sides of the copper foil laminate 30, the inner wall of the blind via 13, and the connection hole 32 (S400).

In the forming of the copper plating layer 36 (S400), as shown in FIG. 8, roughness is formed on both sides of the copper foil laminate 30, the inner wall of the blind via hole 13, and the inside of the connection hole 32 (S410). By forming roughness through the smear treatment process, the seed layer 34 may be easily formed during the electroless plating process.

Then, as shown in FIG. 9, the seed layer 34 is formed on both sides of the copper foil laminate 30, the inner wall of the blind via hole 13, and the connection hole 32 through electroless plating (S420). The seed layer 34 becomes a base layer on which a plating layer may be formed, for example, the core substrate 10, which is an insulating material, in an electroplating process to be described later.

Then, as shown in FIG. 10, by performing electrolytic copper plating on the seed layer 34 (S430), the copper plating layer is formed on both sides of the copper foil laminate 30, the inner wall of the blind via hole 13, and the inside of the connection hole 32. 36 can be formed.

By performing copper plating as shown in FIG. 10, both the upper and lower surfaces of the core substrate 10 may be connected to the copper plating layer 36 to be integrally formed.

Next, as shown in FIGS. 11 to 13, the circuit pattern 40 and the via land 16 are formed on the core substrate 10 (S500).

First, as shown in FIG. 11, an etching resist 38 is formed on the copper plating layer 36 (S510). An etching resist 38 having a shape of the circuit pattern 40 and the via land 16 to be formed is formed in the copper plating layer 36.

Then, as shown in FIG. 12, an etching process is performed by supplying an etching solution to the copper plating layer 36 on which the etching resist 38 is formed (S520). Here, the portion where the etching resist 38 is formed is not etched by the etching liquid. Therefore, only the portions exposed by the etching resist 38 are etched.

Then, after the etching process is finished, as shown in FIG. 13, by removing the etching resist 38 (S530), the circuit pattern 40 and the via land 16 may be formed. In addition, by removing the etching resist 38, the shape of the blind via 12 and the via land 16 integrally formed through copper plating is completed. In the copper plating process of FIG. 10 described above, the blind via 12 and the via land 16 are integrally formed while being connected through the connection unit 18.

Meanwhile, after the circuit patterns 40 and the via lands 16 are formed on the core substrate 10, the solder ball pads 20 formed in contact with the via lands 16 are formed as shown in FIG. 14 (S600). As illustrated in FIG. 15, the solder resists 22 may be formed on both surfaces of the core substrate 10 except for the solder ball pads 20 that need to be connected to the outside.

The solder ball pad 20 may be formed by plating nickel (Ni) or gold (Au) at a position where the solder ball pad is formed. The solder ball pad 20 may be connected to an external substrate by a solder ball where the solder ball is seated.

According to the present embodiment, a printed circuit board having a VOP (Via On Pad) structure, which is resistant to external impact and has excellent electrical reliability, through a solder ball pad and a solder ball structure directly contacting the via land 16 connected integrally with the blind via 12. Can provide.

According to one embodiment of the present invention, since the blind via 12 and the via land 16 are integrally connected, the cracks generated at the interface between the conventional blind via 12 and the via land 16 during external impact are reduced. .

Accordingly, a printed circuit board having improved reliability of electrical connection may be provided through a printed circuit board and a manufacturing method thereof according to an embodiment of the present invention.

Many embodiments other than the above-described embodiments are within the scope of the claims of the present invention and described above with reference to the preferred embodiments of the present invention, but those of ordinary skill in the art will have the following claims It will be understood that various modifications and variations can be made in the present invention without departing from the spirit and scope of the invention as described.

1 is a cross-sectional view showing a blind via of a printed circuit board according to the prior art.

2 is a cross-sectional view illustrating a blind via of a printed circuit board according to an exemplary embodiment of the present invention.

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

4 to 15 are flowcharts illustrating a method of manufacturing a printed circuit board according to an exemplary embodiment of the present invention.

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

1: Core Substrate 2: Blind Via

4: copper foil 6: via land

8: solder ball pad 9: solder resist

10: core substrate 12: blind via

13: blind via hole 14: copper foil

16: Via Land 18: Connection

20: solder ball pad 22: solder resist

30: copper foil laminated sheet 32: connection hole

34: seed layer 36: copper plating layer

38: etching resist 40: circuit pattern

42: opening of blind via

Claims (11)

A core substrate; A blind via formed in the core substrate and having an opening formed in one surface direction of the core substrate; Copper foil formed on the other surface of the core substrate at the position where the blind via is formed; A via land stacked on the copper foil; And And a connection part penetrating through the copper foil and integrally connecting the blind via and the via land. The method of claim 1, The printed circuit board further comprises a solder ball pad formed in contact with the via land. The method of claim 2, The solder ball pads are made of a material containing nickel (Ni) and gold (Au). Providing a copper foil laminate in which copper foil is laminated on both sides of the core substrate; Forming a blind via hole from one surface of the copper foil laminate; Forming a connection hole connected to the blind via hole on the other surface of the copper foil laminate; Forming a copper plating layer on both sides of the copper foil laminate, the inner wall of the blind via hole, and the connection hole; And Forming a circuit pattern and a via land on the core substrate. The method of claim 4, wherein Forming the blind via hole, Etching copper foil on one surface of the copper foil laminate at a position where the blind via hole is formed; And And etching the core substrate by laser processing. The method of claim 4, wherein Forming the connection hole, A method for manufacturing a printed circuit board, which is performed by drilling a copper foil on the other surface of the copper foil laminated plate through a laser processing process or an etching process. The method of claim 4, wherein Forming the copper plating layer, Forming a seed layer on both sides of the copper foil laminate plate, the inner wall of the blind via hole, and the connection hole through electroless plating; And And electrolytic copper plating on the seed layer. The method of claim 4, wherein Forming a circuit pattern and a via land on the core substrate, Forming an etching resist on the copper plating layer; Supplying an etching solution to the copper plating layer; And And removing the etching resist. The method of claim 4, wherein And forming a solder ball pad formed in contact with the via land. The method of claim 9, Forming the solder ball pad, Printed circuit board manufacturing method characterized in that is performed by plating nickel (Ni) and gold (Au) at the position where the solder ball pad is formed. The method of claim 7, wherein Prior to forming the seed layer, And forming roughness on both surfaces of the copper foil laminate, the inner wall of the blind via hole, and the connection hole.

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