KR100662643B1 - Laminating method for multi layer flexible printed circuit board - Google Patents

Abstract

A method for laminating a multilayer FPCB(Flexible Printed Circuit Board) is provided to prevent twist of an inter-layer and a copper plating defect by using a thermal pressurizing process. A predetermined number of inner-layer bases(10) having inner-circuits are provided. An inner-layer cover lay(20) is attached to the respective inner-layer bases. The inner-base is attached to the inner-layer cover lay by attaching heat plates on the respective inner-layer bases. The inner-layer bases having the inner-layer cover lay are combined with each other and pressurized using heat, so that an inner-layer is formed. Outer-layer bases are attached to upper and lower surfaces of the inner-layer and heat is applied on the result, so that outer-layer bases are laminated on the upper and lower surfaces of the inner-layer. Outer-layer circuits are formed on the upper and lower outer-layer bases and outer-layer cover lays are attached to surfaces of the upper and lower outer-layer bases. Heat is applied on the outer-layer base and the outer-layer cover lay.

Description

Lamination method of multilayer flexible circuit board {LAMINATING METHOD FOR MULTI LAYER FLEXIBLE PRINTED CIRCUIT BOARD}

1A to 1H are cross-sectional views illustrating a lamination process sequence for explaining a lamination method of a multilayer flexible circuit board according to the present invention.

Figure 2 is a view showing for explaining the thermocompression principle in the method of laminating a multi-layer flexible circuit board according to the present invention.

Explanation of symbols on the main parts of the drawings

10: inner layer base 20: inner layer coverlay

30: outer layer base 40: outer layer coverlay

I / L: Inner Layer O / L: Outer Layer

The present invention relates to the fabrication of a flexible circuit board forming a multi-layer structure, and more particularly, to simplify the lamination process by improving the lamination process applied in the manufacture of the multi-layer flexible circuit board and thereby the overall lamination process The present invention relates to a lamination method of a multilayer flexible circuit board which enables shortening and reduces process cost required for a lamination process, as well as improving process efficiency and productivity.

In general, flexible printed circuit boards (FPCBs) are flexible printed circuit boards that have a characteristic of being able to be bent as compared to rigid printed circuit boards (PCBs). Along with the development of electronic technology and semiconductor integrated technology, there is an increasing demand for multi-layer flexible circuit boards that enable three-dimensional wiring to increase circuit integration.

In manufacturing the multilayer flexible circuit board, a lamination process for forming a multilayer structure is indispensable, and may have a great influence on the production quality of the multilayer flexible circuit board.

Here, the lamination process refers to laminating a base film for forming a circuit pattern of a flexible circuit board and a cover lay (C / L; cover lay) functioning as a surface insulator by applying high temperature and high pressure or using an adhesive component between layers. The process of laminating | stacking a layer is called.

Usually, by such a lamination process, an inner layer in which an inner layer coverlay is laminated on an inner layer base and an outer layer in which an outer layer coverlay is laminated on an outer layer base are laminated.

In this case, a copper clad laminate (CCL) film processed to stack copper foil on one or both surfaces of the polyimide film is generally used as the inner layer base and the outer layer base, and a polyimide film is usually used as the inner layer coverlay and the outer layer coverlay. .

However, according to the lamination process performed in the manufacture of the multilayer flexible circuit board according to the prior art, there was a problem that it takes a long time from the first lamination by the process of hot-pressing the inner layer coverlay on each of a plurality of inner layer bases. Due to this, there was a problem in that the time required for the final lamination process was generally long, and the process cost was also high. Therefore, it was difficult to pursue efficiency in terms of process performance or productivity.

Furthermore, according to the conventional lamination process, there is a problem in that copper plating defects occur during copper plating due to interlayer distortion or such interlayer distortion, which causes deterioration in quality of the multilayer flexible printed circuit board.

The present invention has been made in view of the above-described conventional problems, and an object thereof is to improve the lamination process applied when fabricating a multi-layer flexible circuit board, thereby simplifying the lamination process, thereby improving the overall lamination process. The present invention provides a method of stacking multilayer flexible circuit boards that can shorten and reduce the process cost required for the lamination process, as well as improve process efficiency and productivity.

In addition, the present invention is to provide a method for laminating a multilayer flexible circuit board which can improve the quality by improving the lamination process to remove the defects such as interlayer distortion or copper plating defects by the existing lamination method.

The present invention for achieving the above object comprises the steps of providing an inner layer base formed with an inner layer circuit to the required number; Attaching an inner layer coverlay to each of the inner layer bases on which the inner layer circuits are formed, and closely bonding the inner layer base and the inner layer coverlay to each of the inner layer bases to which the inner layer coverlay is welded by thermal pressing with a hot plate; Laminating an inner layer base for each layer including the inner layer coverlay, and then forming an inner layer by laminating by thermal pressing by a hot plate; Stacking the outer layer base on the upper and lower sides of the inner layer, and then performing thermal compression on a hot plate to laminate the outer layer base on the upper and lower layers of the inner layer; The outer layer is formed by forming an outer layer circuit on the upper and lower outer layer bases, and then attaching the outer layer coverlay to the surface of the upper and lower outer layer bases, respectively, and performing thermocompression bonding with a hot plate to laminate the outer layer base and the outer layer coverlay. It is characterized by the technical configuration that is made, including the step of completing the lamination process while being formed.

Here, the thermocompression by the hot plate is preferably made under the conditions of temperature conditions 150 ~ 160 ℃, pressure conditions 50 ~ 55kgf / ㎠ and thermocompression time 120 ± 30min.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

1A to 1H are cross-sectional views illustrating a lamination process sequence for explaining a lamination method of a multi-layer flexible circuit board according to the present invention, and FIG. 2 is a thermocompression principle in the lamination method of a multi-layer flexible circuit board according to the present invention. It is a schematic diagram shown to illustrate.

First, as illustrated in FIG. 1A, a plurality of inner layer bases 10 having inner layer circuits formed therein are provided in accordance with a required number.

For example, when manufacturing a multilayer flexible printed circuit board having a five-layer structure as shown, three inner layer bases necessary for two-layer, three-layer, and four-layer inner layer except for the outer layer structure of one layer and five layers. It is to be provided.

Here, as the inner layer base 10, a copper clad laminate (CCL) film processed to stack copper foil on one or both surfaces of a polyimide film is generally used.

The inner layer coverlay (C / L) 20 is welded to each of the inner layer bases 10 on which the inner layer circuit is formed, and as shown in FIG. 1B, the inner layer base 10 to which the inner layer coverlay 20 is foldable is attached. By inner compression of the inner layer coverlay 20 to the inner layer base 10 by thermal compression using a thermocompressor, an inner film (I / F) for forming the inner layer of the multilayer flexible circuit board is required. Equipped to fit.

Here, the thermocompressor is a thermocompression bonding of the product using a hot plate as shown in Figure 2, the inner layer coverlay 20 in the state welded to the inner layer base 10 in one operation through the plate member of the hot plate. To be tightly coupled.

The inner layer coverlay 20 is to function as a surface insulator, a polyimide film is usually used.

Subsequently, after laminating a plurality of inner layer films of each layer provided by thermocompression bonding, a plurality of inner layer films in a laminated state are subjected to thermocompression bonding by the hot plate 1 as shown in FIG. 2, as shown in FIG. 1C, The inner layer film of each layer is laminated in complete contact. As a result, the inner layer (I / L) formation is completed.

After laminating the outer layer base 30 to the upper and lower sides of the inner layer (I / L) in which the inner layer film is laminated for each layer, and then performing thermocompression bonding through the hot plate as described above, the multilayer structure as shown in FIG. 1D. The outer layer base 30 is stacked above and below the inner layer I / L.

Here, the outer layer base 30 is a copper foil laminated (CCL) film processed so that copper foil is laminated on one side or both sides of the polyimide film as in the inner layer base.

Then, an outer layer circuit is formed on each of the upper and lower outer layer bases 30, and then the outer layer coverlays 40 are welded onto the surface of the upper and lower outer layer bases 30, respectively, and the hot plate 1 as described above. 1), the outer layer base 30 and the outer layer coverlay 40 are laminated so as to be in close contact with each other. As a result, the outer layer (O / L) formation is completed and the lamination process is completed.

In this case, a polyimide film is usually used as the outer coverlay 40.

In addition, the lamination and temporary welding is to form a temporary bonding state between the layers by applying an adhesive between the layer and the layer or by overlapping the adhesive sheet to form an adhesive layer.

In addition, the thermocompression operation of the product through the above-mentioned hot plate is preferably made under the conditions of temperature conditions 150 ~ 160 ℃, pressure conditions 50 ~ 55kgf / ㎠ and thermocompression time 120 ± 30min.

As described above, according to the lamination method of the multilayer flexible circuit board according to the present invention, the lamination process is simplified and the overall lamination process can be shortened due to the improvement of the lamination process by performing the thermocompression bonding process. Not only can the process cost be reduced, but it is also useful for improving process efficiency and productivity. Accordingly, it is possible to reduce costs and shorten the delivery date, thereby increasing the product competitiveness.

Furthermore, by improving the lamination process by the thermocompression process, defects such as interlayer distortion and copper plating defects caused by the existing lamination method can be eliminated, thereby improving the quality.

Claims (2)

Providing an inner layer base on which an inner layer circuit is formed, as necessary; Attaching an inner layer coverlay to each of the inner layer bases on which the inner layer circuits are formed, and closely bonding the inner layer base and the inner layer coverlay to each of the inner layer bases to which the inner layer coverlay is welded by thermal pressing with a hot plate; Laminating an inner layer base for each layer including the inner layer coverlay, and then forming an inner layer by laminating by thermal pressing by a hot plate; Stacking the outer layer base on the upper and lower sides of the inner layer, and then performing thermal compression on a hot plate to laminate the outer layer base on the upper and lower layers of the inner layer; The outer layer is formed by forming an outer layer circuit on the upper and lower outer layer bases, and then attaching the outer layer coverlay to the surface of the upper and lower outer layer bases respectively, and performing thermocompression bonding with a hot plate to laminate the outer layer base and the outer layer coverlay. A method of laminating a multi-layer flexible circuit board comprising the step of completing the lamination process while being formed. The method of claim 1, The method of laminating the multilayer flexible circuit board, wherein the thermocompression bonding by the hot plate is performed under conditions of a temperature of 150 to 160 ° C., a pressure of 50 to 55 kgf / cm 2, and a thermo compression time of 120 ± 30 min.

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