KR101108816B1 - Multilayer printed circuit substrate and method of manufacturing the same - Google Patents

Abstract

The present invention relates to a multilayer printed circuit board and a method of manufacturing the same, and includes a metal pattern for protecting a circuit wiring layer in a wet process after formation of a via hole, thereby preventing voids in the via to improve electrical connection defects and long-term reliability. The present invention relates to a multilayer printed circuit board and a method of manufacturing the same.

Description

Multilayer printed circuit board and method of manufacturing the same

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a multilayer printed circuit board and a method of manufacturing the same, and to a multilayer printed circuit board having a metal pattern for protecting a circuit wiring layer in a wet process after via holes are formed and a method of manufacturing the same.

Recently, due to the high portability of electronic devices, high functionality, internet, video, and high capacity data transmission, the design of printed circuit boards is more complicated, and the demand for high density and miniaturized circuits is increasing. Interest is growing.

Multi-layer printed circuit boards are widely manufactured by semi-additive process using prepreg as an insulator according to the trend of thin and short and high density.

The semi-additive process first forms an innerlayer circuit board. Thereafter, the prepreg is laminated on the inner circuit board. At this time, in order to improve the adhesion between the prepreg and the circuit layer, an insulating layer is further formed on the prepreg. A via hole exposing a portion of the inner layer circuit is formed in the prepreg and the insulating layer. Thereafter, after forming the electroless plating layer on the insulating layer, a plating resist pattern of a predetermined pattern is formed on the electroless plating layer. Thereafter, vias and outer layer circuit layers may be formed by electroplating using a plating resist pattern.

Here, the insulating layer may be laminated on the prepreg in the form of an insulating sheet for easy processing. The insulating sheet may include a metal foil and an insulating film formed on the metal foil. The metal foil may serve to protect the surface of the insulating film as well as the base layer for forming the insulating film.

Here, the metal foil may be removed by a wet etching method after forming the via hole in the insulating layer. In this case, a crevice may be formed in the inner layer circuit by etching the surface of the inner layer circuit exposed by the via hole in the wet etching process.

The gap formed in the inner layer circuit may cause voids to be generated in the via in the plating process for forming the vias, which may result in poor electrical connection and long-term reliability of the multilayer printed circuit board.

Accordingly, the present invention was devised to solve a problem that may occur in a multilayer printed circuit board and a method of manufacturing the same. Specifically, the present invention provides a metal pattern for protecting a circuit wiring layer in a wet process after formation of a via hole. It is an object of the present invention to provide a multilayer printed circuit board and a method for manufacturing the same, which can prevent voids from occurring and improve electrical connection defects and long-term reliability.

It is an object of the present invention to provide a multilayer printed circuit board. The multilayer printed circuit board includes a core layer; First circuit layers disposed on both surfaces of the core layer; A metal pattern disposed on the first circuit layer, the metal pattern having an opening that exposes a portion of the first circuit layer; A second insulating layer having a via hole corresponding to the opening and disposed on an upper surface of the core layer including the metal pattern; Vias formed in the via holes and the openings; And a second circuit layer electrically connected to the first circuit layer through the via and disposed on the second insulating layer.

The metal pattern may have an etching selectivity different from that of the first circuit layer.

In addition, the metal pattern may have a stronger adhesive force with the second insulating layer than the first circuit layer.

In addition, the metal pattern may be made of any one of nickel, nickel alloys, aluminum and aluminum alloys.

The second insulating layer may include a prepreg and an insulating resin film disposed on the prepreg.

Another object of the present invention is to provide a method of manufacturing a multilayer printed circuit board. The manufacturing method includes forming a first circuit layer and a metal pattern disposed on the first circuit layer on both surfaces of the core layer, respectively; Stacking an insulating layer having a metal foil on a surface of the core layer including the metal pattern; Forming a via hole exposing the metal pattern in the insulating layer; Removing the metal foil; Forming an opening corresponding to the via hole in the metal pattern; And forming a via disposed in the via hole and the opening, and a second circuit layer electrically connected to the first circuit layer through the via and disposed on the insulating layer.

The metal pattern may have an etching selectivity different from that of the first circuit layer.

In addition, the metal pattern may have a stronger adhesive force with the insulating layer than the first circuit layer.

In addition, the metal pattern may be made of any one of nickel, nickel alloys, aluminum and aluminum alloys.

In addition, the insulating layer may include a prepreg and an insulating resin film disposed on the prepreg.

In addition, the metal foil may be formed of copper.

In addition, the step of forming the metal pattern disposed on the first circuit layer and the first circuit layer on each side of the core layer,

Providing a copper foil laminate comprising a core layer and a metal layer having an etching selectivity different from that of the copper layer and the copper layer on both sides of the core layer; And etching the copper layer and the metal layer to form the metal pattern and the first circuit layer.

In addition, the step of forming the metal pattern disposed on the first circuit layer and the first circuit layer on each side of the core layer,

Providing a copper foil laminate comprising a core layer and copper layers disposed on both sides of the core layer; Etching the copper layer to form a first circuit layer; And selectively forming the metal pattern on a first circuit layer of a region corresponding to the via hole forming region.

The multilayer printed circuit board of the present invention includes a metal pattern for protecting the circuit wiring layer in the wet process after the via hole is formed, thereby preventing voids in the via, thereby improving electrical connection defects and long-term reliability.

In addition, the metal pattern provided in the multilayer printed circuit board of the present invention is made of a material having a strong adhesive force with the prepreg of the insulating layer compared to the circuit wiring layer, it is possible to further improve the reliability of the multilayer printed circuit board.

1 is a cross-sectional view of a multilayer printed circuit board according to a first embodiment of the present invention.
2 to 9 are cross-sectional views illustrating a manufacturing process of a multilayer printed circuit board according to a second exemplary embodiment of the present invention.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings of a multilayer printed circuit board. The following embodiments are provided by way of example so that those skilled in the art can fully understand the spirit of the present invention. Therefore, the present invention is not limited to the embodiments described below, but may be embodied in other forms. In the drawings, the size and thickness of the device may be exaggerated for convenience. Like numbers refer to like elements throughout.

1 is a cross-sectional view of a multilayer printed circuit board according to a first embodiment of the present invention.

Referring to FIG. 1, a multilayer printed circuit board according to a first exemplary embodiment of the present invention may include a core layer 110, a first circuit layer 120, a metal pattern 130, an insulating layer 140, and a via 150. , And the second circuit layer 160.

Here, the first circuit layer 120 may be disposed on both sides of the core layer 110, respectively. The core layer 110 may be made of an insulating resin. The core layer 110 may include at least one of an epoxy resin, a phenol resin, a polyimide resin, and a FR4 (heat resistant glass epoxy epoxy resin). However, in the embodiment of the present invention, it is not limited to the material of the core layer.

Although not shown in the drawings, the core layer 110 may further include core vias for electrically connecting the first circuit layers 120 disposed on both surfaces thereof.

The metal pattern 130 may be disposed on the first circuit layer 120. Although the metal pattern 130 is illustrated as being disposed on the entire surface of the first circuit layer 120, the metal pattern 130 is not limited thereto. The metal pattern 130 may be selectively disposed around the formation area of the via hole 141.

Here, the metal pattern 130 may be formed of a metal having an etching selectivity different from that of the first circuit layer 120. As a result, the metal pattern 130 may serve to protect the first circuit layer 120 that may be exposed to the etchant used in the manufacturing process of the multilayer printed circuit board. Here, the role of the metal pattern 130 to protect the first circuit layer 120 will be clearly understood in the description of the manufacturing process to be described later.

In addition, the metal pattern 130 may be formed of a material having a strong adhesive force with the prepreg 140a constituting the insulating layer 140, in particular, the insulating layer 140 compared to the first circuit layer 120. For example, when the first circuit layer 120 is formed of copper, the metal pattern 130 may be formed of any one of nickel, nickel alloys, aluminum, and aluminum alloys.

Accordingly, the metal pattern 130 serves to protect the first circuit layer 120 exposed by the via hole 141, and at the same time improves the bonding force between the first circuit layer 120 and the insulating layer 140. Can play a role.

The metal pattern 130 may have an opening 131 corresponding to the via hole 141. Here, the first circuit layer 120 and the via 150 may be electrically connected to each other through the opening 131.

The insulating layer 140 may be disposed on an upper surface of the core layer 110 including the metal pattern 130. In addition, the insulating layer 140 may include a via hole 141 corresponding to the opening 131 of the metal pattern 130. The insulating layer 140 may include a prepreg 140a disposed on the top surface of the core layer 110 and an insulating resin film 140b disposed on the prepreg 140a. Here, the prepreg 140a may be made of an insulating resin impregnated with glass fibers. In addition, the insulating resin film 140b may serve to increase the adhesion between the prepreg 140a and the second circuit layer 160. Here, examples of the material for forming the insulating resin film 140b may include any one or two or more of an epoxy resin, a phenol resin, a polyimide resin, and FR4 (heat-resistant glass epoxy resin). However, in the embodiment of the present invention, the material of the insulating resin film 140b is not limited.

The via 150 may be disposed to penetrate through the insulating layer 140 to perform interlayer connection of the circuit layer. That is, the via 150 may be disposed in the via hole 141 and the opening 131. Thus, the via 150 may electrically connect the first circuit layer 120 exposed by the via hole 141 and the opening 131 and the second circuit layer 160 to be described later.

In addition, since the via 150 is disposed not only on the upper surface of the first circuit layer 120 but also on the wall forming the opening of the metal pattern 130, an electrical connection area through the via 150 may be increased.

The second circuit layer 160 may be disposed on the insulating layer 140. In this case, the second circuit layer 160 may be electrically connected to the first circuit layer 120 through the via 150.

In addition, in the embodiment of the present invention, the multilayer printed circuit board is illustrated and described with a two-layer structure. However, the present invention is not limited thereto. And circuit layers may be stacked such that they are alternately arranged. In this case, additional metal patterns may be provided on the stacked circuit layers, respectively, to prevent formation of gaps in the stacked circuit layers in a wet process performed after via holes are formed.

In addition, the multilayer printed circuit board may further include a pad electrode and a solder resist exposing a part of the pad electrode to be electrically connected to the external circuit unit on the uppermost layer.

Therefore, as in the embodiment of the present invention, the multilayer printed circuit board includes a metal pattern for protecting the circuit wiring layer from the etching solution, thereby preventing voids from occurring in the vias, thereby improving electrical failure and long-term reliability. .

In addition, the metal pattern is made of a material having excellent bonding strength with the prepreg of the insulating layer compared to the circuit wiring layer, it is possible to further improve the reliability of the multilayer printed circuit board.

In addition, the metal pattern has an opening corresponding to the via hole, and a via is formed inside the opening, thereby increasing an electrical connection area through the via.

2 to 9 are cross-sectional views illustrating a manufacturing process of a multilayer printed circuit board according to a second exemplary embodiment of the present invention.

Referring to Figure 2, to manufacture a multilayer printed circuit board, a copper foil laminated board is provided. Here, the copper foil laminate may include a core layer 110 and a copper layer 122 disposed on both surfaces of the core layer 110. In this case, the metal layer 132 having an etching selectivity different from that of copper may be formed on the copper layer 122. In addition, the metal layer 132 may be made of a material having excellent adhesive strength with the prepreg 140a to be described later than the copper layer 122. Here, as an example of the material for forming the metal layer 132 may be made of any one of nickel, nickel alloys, aluminum and aluminum alloys.

Referring to FIG. 3, metal patterns 130 disposed on the first circuit layer 120 and the first circuit layer 120 are formed on both surfaces of the core layer 110.

In this case, in order to form the first circuit layer 120 and the metal pattern 130, a resist pattern is first formed on the metal layer 132, and then the metal layer 132 is etched using the resist pattern as an etching mask. The pattern 130 is formed. Thereafter, the first circuit layer 120 may be formed by etching the copper layer 122 using the resist pattern as an etching mask. Here, as the metal layer 132 and the copper layer 122 have different etching selectivity, the resist pattern used to form the metal pattern 130 is removed and the metal pattern 130 is used as an etching mask. One circuit layer 120 may be formed.

In addition, before the process of forming the first circuit layer 120 and the metal pattern 130, the through hole penetrating through the core layer 110, the copper layer 122 and the metal layer 132, and then through The conductive paste may be filled in the holes to further form core vias (not illustrated) to electrically connect the first circuit layers 120 disposed on both surfaces of the core layer 110.

Referring to FIG. 4, a prepreg 140a and an insulating resin film 140b are provided on the core layer 110 including the metal pattern 130. Here, a metal foil 140c is attached on the insulating resin film 140b to protect the surface. In addition, the metal foil 140c may be made of copper. In addition, the insulating resin film 140b may serve to increase adhesion between the prepreg 140a and the second circuit layer 160 formed in a subsequent process.

Referring to FIG. 5, the prepreg 140a disposed on the core layer 110 including the metal pattern 130 and the insulating resin film 140b having the metal foil 140c formed on the surface thereof are thermally compressed to form a metal pattern ( The insulating layer 140 may be stacked on the core layer 110 including the 130. In this case, the bonding force of the first circuit layer 120 and the prepreg 140a may be improved by the metal pattern 130.

Referring to FIG. 6, a via hole 141 for exposing a part of the first circuit layer 120 may be formed in the insulating layer 140. The via hole 141 may be formed through an etching process through a laser drill method, a mechanical drill method, or a photolithography process.

Referring to FIG. 7, the metal foil 140c disposed on the insulating resin film 140b is removed. The metal foil 140c may be removed by a wet etching method. Here, since the metal foil 140c and the first circuit layer 120 are made of the same material, the surface of the first circuit layer 120 may also be etched in a wet process to form a crevice. However, as the first circuit layer 120, that is, the metal pattern 130 having an etching selectivity different from that of copper is provided on the first circuit layer 120, the metal pattern 130 is subjected to the first circuit in a wet process. By protecting the surface of the layer 120, it is possible to prevent the formation of a gap in the first circuit layer 120.

Referring to FIG. 8, an opening 131 for exposing the first circuit layer 120 is formed in the metal pattern 130. In this case, the opening 131 of the metal pattern 130 may be removed by an etching process. In this case, the opening 131 is formed to correspond to the via hole 141.

9, a second circuit layer 160 is formed on the insulating layer 140. Here, the second circuit layer 160 may be formed through a plating process. In addition, in the process of forming the second circuit layer 160, the vias 150 disposed in the via holes may be simultaneously formed. In this case, the via 150 may be formed not only in the via hole 141 but also in the opening 131 of the metal pattern 130 to electrically connect the first and second circuit layers 120 and 160 to each other.

In the embodiment of the present invention, the metal pattern has been described as being formed by patterning a metal layer disposed on the copper clad laminate, but is not limited thereto. For example, after the first circuit layer is formed on the core layer, a metal pattern may be selectively formed on the first circuit layer in a region corresponding to the via hole formation region. In this case, the metal pattern may be formed through a deposition process or a printing method.

In addition, in the embodiment of the present invention, the multilayer printed circuit board is illustrated and described with a two-layer structure, but is not limited thereto. That is, the multilayer printed circuit board is stacked such that the insulating layer and the circuit layer are alternately arranged. The buildup process may be further performed to form a structure of two or more layers. In this case, an additional metal pattern may be formed on each of the stacked circuit layers, thereby preventing formation of gaps in the stacked circuit layers in the wet etching process after the via hole formation, and increasing the interlayer bonding force.

In addition, the multilayer printed circuit board may further form a pad electrode and a solder resist exposing a part of the pad electrode to be electrically connected to the external circuit portion on the uppermost layer.

Therefore, as in the embodiment of the present invention, the multilayer printed circuit board includes a metal pattern for protecting the circuit wiring layer, thereby preventing formation of a gap in the circuit wiring layer in a wet process.

In addition, the metal pattern is made of a material having excellent bonding strength with the prepreg of the insulating layer compared to the circuit wiring layer, it is possible to improve the bonding reliability of the multilayer printed circuit board.

110: core layer
120: first circuit layer
130: metal pattern
131 opening
140: insulation layer
141: via hole
150: Via
160: second circuit layer

Claims (13)

Core layer;
First circuit layers disposed on both surfaces of the core layer;
A metal pattern disposed on the first circuit layer, the metal pattern having an opening that exposes a portion of the first circuit layer;
An insulating layer having a via hole corresponding to the opening and disposed on an upper surface of the core layer including the metal pattern;
Vias formed in the via holes and the openings; And
A second circuit layer electrically connected to the first circuit layer through the via and disposed on the insulating layer;
Including;
The insulating layer includes a prepreg and an insulating resin film disposed on the prepreg.
The method of claim 1,
And the metal pattern has an etching selectivity different from that of the first circuit layer.
The method of claim 1,
The metal pattern has a stronger adhesive force with the insulating layer than the first circuit layer.
The method of claim 1,
The metal pattern is a multilayer printed circuit board made of any one of nickel, nickel alloys, aluminum and aluminum alloys.
delete Forming metal patterns disposed on the first circuit layer and the first circuit layer on both sides of the core layer, respectively;
Stacking an insulating layer having a metal foil on a surface of the core layer including the metal pattern;
Forming a via hole exposing the metal pattern in the insulating layer;
Removing the metal foil;
Forming an opening corresponding to the via hole in the metal pattern; And
Forming a via disposed in the via hole and the opening and a second circuit layer electrically connected to the first circuit layer through the via and disposed on the insulating layer;
Method of manufacturing a multilayer printed circuit board comprising a.
The method according to claim 6,
And the metal pattern has an etch selectivity different from that of the first circuit layer.
The method according to claim 6,
The metal pattern has a stronger adhesive force with the insulating layer than the first circuit layer manufacturing method of a multilayer printed circuit board.
The method according to claim 6,
The metal pattern is a method of manufacturing a multilayer printed circuit board made of any one of nickel, nickel alloys, aluminum and aluminum alloys.
The method according to claim 6,
And the insulating layer comprises a prepreg and an insulating resin film disposed on the prepreg.
The method according to claim 6,
The metal foil is a method of manufacturing a multilayer printed circuit board formed of copper.
The method according to claim 6,
Forming a metal pattern disposed on each of the first circuit layer and the first circuit layer on both sides of the core layer,
Providing a copper foil laminate comprising a core layer and a metal layer having an etching selectivity different from that of the copper layer and the copper layer on both sides of the core layer; And
And etching the copper layer and the metal layer to form the metal pattern and the first circuit layer.
The method according to claim 6,
Forming a metal pattern disposed on each of the first circuit layer and the first circuit layer on both sides of the core layer,
Providing a copper foil laminate comprising a core layer and copper layers disposed on both sides of the core layer;
Etching the copper layer to form a first circuit layer; And
And forming the metal pattern selectively on the first circuit layer in a region corresponding to the via hole formation region.

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