KR100745520B1 - Multi-layered printed circuit board and the manufacturing method thereof - Google Patents

Abstract

A multilayer printed circuit board and a method of manufacturing the same are disclosed. A printed circuit board comprising a plurality of circuit pattern layers, each of which comprises a plurality of land portions formed on the plurality of circuit pattern layers and aligned in a thickness direction of the printed circuit board, and an outer layer circuit formed on the surface of the printed circuit board. And a PTH penetrating through the plurality of land portions and the outer layer circuit, and a conductive material filled in the PTH.

Printed Circuit Boards, IVH, BVH, Plating

Description

Multi-layered printed circuit board and its manufacturing method

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

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

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

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

10: core substrate 12: inner layer circuit

20: insulation layer 22: outer layer circuit

30: land part 40: PTH

42: conductive paste

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

In the conventional multilayer printed circuit board, an inner layer circuit is formed by applying an additive method or a subtractive method to the surface of a core substrate such as a copper clad laminate (CCL), and an insulating layer and a metal layer are sequentially stacked. It is manufactured by forming the outer layer circuit in the same way as the inner layer circuit while building (up).

In the manufacturing process of multilayer printed circuit boards, the interstitial via hole (IVH), blind via hole (BVH), and plated through hole (PTH) are used for electrical connection between circuit patterns of each layer, and electrical connection between circuit patterns and electronic devices. Various via holes are formed.

That is, in the manufacturing process of the multilayer printed circuit board according to the prior art, first, IVH is drilled and drilled into a core substrate such as CCL, and a plating layer is formed on the surface of the core substrate and the inner circumferential surface of the IVH by copper plating, and the inner space of the IVH Is filled with a conductive material, the surface is polished, and an inner layer circuit is formed by applying an additive method or a subtractive method to the surface of the core substrate.

Next, after both surfaces of the core substrate are inspected (AOI, automatic optical inspection), and after the pretreatment process, an insulating material such as Ajinomoto Build-up Film (ABF) is laminated on the surface of the core substrate, and then a metal layer is formed on the surface. Insulating material having a metal layer formed on the surface, such as Resin coated copper (RCC), is laminated, and BVH is processed for electrical connection between the metal layer and the inner layer circuit by laser drilling.

Next, after the desmear process, electroless copper plating is applied to the surface of the BVH, and an additive circuit method is applied to form an outer layer circuit pattern, a plating layer is formed on the surface of the BVH, and a substrate after flash etching Examine the surface of the (AOI). As a result, a four-layer printed circuit board is formed, and a multilayer printed circuit board is formed by repeating insulating material stacking, laser drilling (BVH formation), additive process, and flash etching process.

Meanwhile, as printed circuit boards such as ball grid array (BGA) are becoming highly integrated, in order to form electrical connection paths that penetrate the entire substrate in a conventional multilayer printed circuit board manufacturing method, a circuit pattern may be used for interlayer electrical connection. The BVHs are aligned in the thickness direction of the substrate to form a so-called 'stack via', which stack vias form BVHs one by one and fill plating to form electrical connection paths in the thickness direction of the entire substrate. Therefore, there is a problem that the stability of the electrical connection and the accuracy of processing is poor.

In addition, there is a limit that it becomes more difficult to align the position of the BVH as the specification of the printed circuit board, such as BGA or package substrate.

The present invention provides a multilayer printed circuit board and a method for manufacturing the multilayer printed circuit board capable of forming a stack via structure that is electrically stable and has high processing accuracy without forming BVH for each layer of the circuit pattern in the multilayer printed circuit board.

According to an aspect of the present invention, in a printed circuit board including a plurality of circuit pattern layers, a plurality of land portions respectively formed in the plurality of circuit pattern layers, the positions of which are aligned in the thickness direction of the printed circuit board, and printing There is provided a multilayer printed circuit board comprising an outer layer circuit formed on the surface of the circuit board, a PTH penetrating through the plurality of land portions and the outer layer circuit, and a conductive material filled in the PTH.

The land portion is preferably formed corresponding to the position where the BVH for electrical connection between the plurality of circuit pattern layers is to be formed. It is preferable that a conductive material is a conductive paste. The printed circuit board is preferably a flip chip ball grid array (FCBGA).

In addition, a method of manufacturing a multilayer printed circuit board which is formed on a plurality of circuit pattern layers and includes a plurality of land portions aligned in a thickness direction of a printed circuit board, the method comprising: (a) forming an inner layer circuit on a surface of a core substrate; Forming (b) sequentially stacking an insulating layer and a circuit pattern layer on the core substrate, (c) drilling a PTH through a plurality of land portions and an inner layer circuit, and (d) a conductive material in the PTH. Provided is a method of manufacturing a multilayer printed circuit board, including the step of filling the same.

Step (c) may be performed by mechanical drilling. It is preferable that a conductive material is a conductive paste. The core substrate is a copper clad laminate, and step (a) is preferably carried out by additive process. Step (b) may include laminating an insulating layer on which the metal layer is stacked, and removing a portion of the metal layer to form a circuit pattern.

The land portion is preferably formed corresponding to the position where the BVH for electrical connection between the plurality of circuit pattern layers is to be formed. The land portion is preferably formed in correspondence with the position where the IVH perforated on the core substrate is to be formed for electrical connection between inner layer circuits formed on both sides of the core substrate.

Hereinafter, a preferred embodiment of a multilayer 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, and in the following description with reference to the accompanying drawings, the same or corresponding components regardless of reference numerals Denotes the same reference numerals and duplicate description thereof will be omitted.

1 is a cross-sectional view illustrating a multilayer printed circuit board according to an exemplary embodiment of the present invention. Referring to FIG. 1, a core substrate 10, an inner layer circuit 12, an insulating layer 20, an outer layer circuit 22, a land portion 30, a PTH 40, and a conductive paste 42 are illustrated. .

The present invention perforates the PTH 40 at a position where a stack via is to be formed by mechanical drilling such as a CNC drill after a build up process to form a stack via in a multilayer printed circuit board. By filling the interior space of the PTH 40 with a conductive paste, it is electrically stable and has improved processing accuracy.

In the present embodiment shown in Fig. 1, the BVH is formed and filled by laser drilling for each circuit layer in order to form a full stack stack via in a '3 + 2 + 3 structure', that is, an 8-layer multilayer printed circuit board. After forming three layers of insulating layer 20 and a circuit pattern without forming a fill plating, the area where full-layer stack vias are to be formed is drilled by a CNC drill, and then a conductive material such as a conductive paste is filled to improve precision. Improved and stable stack vias.

To this end, in the present invention, only the land portion 30 is first formed in the portion of the circuit pattern of each layer in which the via hole is to be formed, followed by building up, and then processing the PTH 40 penetrating the entire substrate and filling the conductive paste 42. Electrical conduction.

In the present exemplary embodiment, the land part 30 may be electrically connected to each of the circuit pattern layers and the via holes when a via hole such as a conductive PTH 40 is formed in the multilayer printed circuit board for electrical conduction between the circuit pattern layers. It is the part that plays the role of mediator

That is, the land portion 30 has a function corresponding to a portion of the 'wing shape' in the cross-section formed on the surface of the substrate of the BVH of the prior art, so that the shape also extends a predetermined distance along the circuit pattern layer in the via hole It is formed of a circuit pattern of a shape.

The shape of the land part 30 according to the present invention does not need to be identically formed for each circuit pattern layer, and is fixed to the surface of the substrate adjacent to the position of the via hole so that electrical conduction between the circuit pattern layers can be realized through the via hole. Part is formed. That is, like the land part of the BVH of the prior art, when formed by a separate plating, it may be formed as a 'donut' type circuit pattern, and when formed by the entire plating on the substrate surface, the circuit pattern It can be formed as part of a layer.

In the multilayer printed circuit board including the plurality of circuit pattern layers according to the present invention, the land portions 30 are formed in the plurality of circuit pattern layers formed in the respective layers. Land portion 30 is formed so that the position is aligned in the thickness direction of the printed circuit board, the plurality of land portion 30 and the outer layer circuit formed on the surface of the printed circuit board aligned after stacking the multilayered printed circuit PTH 40 is penetrated through 22. The PTH 40 may be filled with a conductive material such as the conductive paste 42 to implement an electrical connection path.

In this way, the PTH 40 penetrating the entire substrate functions as a stack via, so that the land portion 30 of each circuit pattern layer through which the PTH 40 penetrates has a BVH in order to form a stack via in the prior art. Is formed at a position where it will be formed continuously.

Meanwhile, although the conductive paste 42 is used in the present embodiment as the conductive material to be filled in the PTH 40, the present invention is not necessarily limited thereto, and a fill plating layer may be formed on the PTH 40 or the like. Of course, it can also be filled with a conductive material that can be implemented within the scope apparent to those skilled in the art.

The multilayer printed circuit board forming the stack vias is applicable to high specification products, and is typically applied to fabrication of flip chip ball grid array (FCBGA) or next generation package substrates.

2 is a flowchart illustrating a method of manufacturing a multilayer printed circuit board according to an exemplary embodiment of the present invention, and FIG. 3 is a flowchart illustrating a process of manufacturing a multilayer printed circuit board according to an exemplary embodiment of the present invention. Referring to FIG. 3, a core substrate 10, an inner layer circuit 12, an insulating layer 20, an outer layer circuit 22, a land portion 30, a PTH 40, and a conductive paste 42 are illustrated. .

In order to manufacture the multi-layer printed circuit board of the present invention, which includes a plurality of land portions 30 respectively formed on the plurality of circuit pattern layers in such a manner that their positions are aligned in the thickness direction of the printed circuit board, first, FIGS. As described above, the inner circuit 12 is formed on the surface of the core substrate 10 (100). In the case of using a common copper clad laminate as the core substrate 10, a part of the copper foil layer laminated on the surface may be removed to form an inner layer circuit 12. In the case of realizing a fine circuit pattern such as a high specification printed circuit board, copper foil may be used. After forming a plating layer on the surface of a laminated board, laminating a dry film, it is good to apply the additive process of forming a circuit pattern through fixing, such as exposure, image development, and etching.

Next, as shown in FIG. 3B, the insulating layer 20 and the circuit pattern layer are sequentially stacked on the core substrate 10 while forming only the land portion 30 without forming BVH in the portion where the stack via is to be formed. As shown in FIG. 3C, a multilayer printed circuit board is formed (110). This can be proceeded by stacking the insulating layer 20 such as ABF and forming a plating layer, and also by sequentially stacking the insulating layer 20 where the metal layer is laminated, such as resin coated copper (RCC). It can also proceed in a manner to form a circuit pattern.

The land part 30 is formed at a position where the BVH for electrical connection between the plurality of circuit pattern layers is to be formed. That is, in the present invention, instead of the conventional method of stacking the circuit pattern and the BVH while forming the circuit pattern and BVH, only the circuit pattern and the land portion 30 are formed on each circuit pattern layer, and thus the land portion 30 is laminated. ) Is formed at the position where BVH would have been formed in the prior art.

Furthermore, the present invention implements the stack via by forming the PTH 40 penetrating not only the land portion 30 of each layer but also the core substrate 10, so that the inner layer formed on both sides of the core substrate 10 in the conventional case. Even in the position where the IVH for the electrical connection between the circuits 12 has been formed, instead of drilling the IVH, only the land portion 30 is formed and then the lamination process is performed.

Next, as illustrated in FIG. 3D, the PTH 40 penetrating through the plurality of land portions 30 and the inner layer circuit 12 is drilled (120). The PTH 40 may be drilled using a mechanical drill such as a CNC drill, and other drilling methods may be used within a range apparent to those skilled in the art.

Finally, as shown in FIG. 3E, a conductive material is filled in the PTH 40 to form a stack via (130). As described above, the conductive material is preferably the conductive paste 42, but the present invention is not necessarily limited to the conductive paste 42 as a filling material.

After the stack via structure is completed as described above, a subsequent process may be performed by applying an existing printed circuit board manufacturing process.

Although the technical spirit of the present invention has been described in detail according to the above-described embodiments, the above-described embodiments are for the purpose of description and not of limitation, and a person of ordinary skill in the art will appreciate It will be understood that various embodiments are possible within the scope.

According to the present invention having such a configuration, since the stack via structure is formed in a multilayer printed circuit board, the density of circuit design per unit area is improved, and PTH is formed at once without stacking BVHs formed in each layer. As a result, the electrical stability is improved, and a more precise stack via structure can be formed.

Claims (6)

In a printed circuit board comprising a plurality of circuit pattern layers, Respectively formed on the plurality of circuit pattern layers, the positions of which are aligned in the thickness direction of the printed circuit board, and corresponding to positions at which blind via holes (BVHs) are to be formed for electrical connection between the plurality of circuit pattern layers. A plurality of land portions; An outer layer circuit formed on a surface of the printed circuit board; A via hole penetrating the plurality of land portions and the outer layer circuit; A multilayer printed circuit board comprising a conductive material filled in the via hole. delete A plurality of circuit patterns each formed on a plurality of circuit pattern layers, the positions of which are aligned in a thickness direction of the printed circuit board, and corresponding to positions at which blind via holes (BVHs) are to be formed for electrical connection between the plurality of circuit pattern layers. A method of manufacturing a multilayer printed circuit board comprising a land portion, (a) forming an inner layer circuit on the surface of the core substrate; (b) sequentially stacking an insulating layer and a circuit pattern layer on the core substrate; (c) drilling a via hole penetrating through the plurality of land portions and the inner layer circuit; And (d) filling a conductive material in the via hole. The method of claim 3, The step (b) is a method of manufacturing a multilayer printed circuit board comprising laminating an insulating layer on which a metal layer is laminated, and removing a part of the metal layer to form a circuit pattern. delete The method of claim 3, And the land portion is formed corresponding to a position at which an interstitial via hole (IVH) is formed in the core substrate for electrical connection between the inner layer circuits formed on both surfaces of the core substrate.

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