KR100874172B1 - Method for manufacturing flexible printed circuit board and metallic wiring pattern of flexible printed circuit board using thereof - Google Patents

Abstract

A method for manufacturing a flexible printed circuit board and a metal wiring pattern of the flexible printed circuit board are provided to prevent oxidation of a wiring pattern when the copper plating layer is exposed to the air and stored for a long time. A flexible copper-clad laminated board is prepared(S10). A photoresist is coated to implement an engraved circuit pattern on a metal conductive layer(S20). The exposure and development are performed(S30,S40). A first plating layer is formed by plating the copper on the metal conductive layer(S50). The engraved pattern of the photoresist is removed(S60). The metal conductive layer exposed except the first plating layer is removed by soft etching(S70). The wiring pattern is stacked by successively plating the nickel plating layer as the second plating layer and the gold plating layer as the third plating layer on the first plating layer(S80).

Description

METHOD FOR MANUFACTURING FLEXIBLE PRINTED PRINTED CIRCUIT BOARD AND METALLIC WIRING PATTERN OF FLEXIBLE PRINTED CIRCUIT BOARD USING THEREOF}

In recent years, as the light and short, high functional and high density of the electronic device is progressed, a light and convenient circuit board is required. However, in the case of the conventional printed circuit board, because the hardness of the substrate itself is too large, it is very difficult to install in a small electronic device and there was a big problem. Therefore, in recent years, a tape carrier type semiconductor package employing a flexible printed circuit board (FPCB) having excellent flexibility has been in the spotlight.

This flexible printed circuit board is a thin, bendable printed board composed of a copper thin film and a resin film.It was originally developed for military use such as missiles, and was adopted for consumer electronic devices such as auto focus cameras. It has been used for various electronic devices by utilizing light weight and flexibility, and recently, optical pick-up part such as DVD (Digital Versatile Disc), liquid crystal around mobile phone, printer, digital camera, hinge Many flexible printed circuit boards are used for the parts.

The flexible printed circuit board is divided into a single-sided flexible printed circuit board and a double-sided printed circuit board, and the former forms a circuit by coating copper foil on one surface of a polyimide film, which is an insulator, which is the most basic structure of a flexible printed circuit board. The latter is a structure in which circuits are formed with both the upper and lower surfaces of the polyimide film, which is an insulating base, bonded to copper foil, and in this structure, lands (solderable places) can be formed on both upper and lower surfaces. When mounting parts, the density of parts can be increased at the same size. However, in the case of the double-sided printed circuit board, the upper and lower patterns of the polyimide film need to be connected, so the cross-sectional structure undergoes unnecessary drilling process and copper plating process as the hole treatment process.

Particularly, such flexible printed circuit boards are used in COF (Chip On Film or Chip On Flexible), which requires microfabrication, and have higher rigidity requirements for hinge cables integrated with multilayer flexible substrates. The required characteristics for the copper thin film vary depending on the method and the part.

First, referring to the wiring pattern forming method of the single-sided flexible printed circuit board, as shown in FIG. 4, the conventional method for manufacturing a flexible semiconductor substrate for COF is made of a subtractive material using copper plating on a polyimide film. As shown in FIG. 4, the conventional method is a flexible copper-clad laminated board (FCCL) in which copper (2) is coated on a cross section of a raw material insulating sheet (1). After applying the photoresist 3 to the photoresist 3 and exposing and developing it, the exposed copper 2 portions other than the portion 3 'where the circuit pattern is formed are etched, and the remaining photoresist 3' is removed and finished. Plating was performed.

However, as the thick copper layer 2 is etched in the etching step, a large amount of copper raw material is lost, and in particular, connection with adjacent circuit patterns due to the formation of a poor circuit pattern, that is, a puddling phenomenon occurring during the etching process. Due to the phenomenon that the electrical insulation resistance between the circuits fall, there was a problem that it is difficult to form a high-density circuit (FINE PITCH) of 10 to 50㎛.

As a solution to this, the present inventors manufacture a flexible printed circuit board using a single-sided build-up method using soft etching or semi-additive technology instead of the subtractive method in the wiring pattern forming method. A method (Korean Patent Registration No. 10-0691336) has been proposed.

As shown in FIG. 5, the method of manufacturing a single-sided flexible printed circuit board using the semi-additive technique includes preparing an insulating sheet (S10), depositing a conductor layer (S20), and forming an embossed pattern. (S30 to S50), the pattern build-up step (S60 and S70), the photoresist removing step (S80) and the etching step (S90), the detailed process is as follows.

First, prepare a polyimide insulating sheet 10 having a thickness of 25㎛ as a raw material (insulation sheet preparation step, S10), and facilitate the copper plating (S60) to be described later on the insulating sheet 10, the copper plating layer 22 In order to improve the adhesion between the insulating sheet 10 and the insulating sheet 10, a conductive layer 21 is deposited to deposit a conductive metal such as copper and copper alloy having a thickness of 0.1 to 0.5 μm (conductor layer deposition step, S20).

Embossed pattern forming step (S30 to S50 step) is to apply the photoresist 50 on the metal deposition layer 21 formed in the conductor layer deposition step (S20) (S30), put a pattern mask 60 thereon After exposure S40 for a predetermined time, the pattern mask 60 is removed to perform development S50.

After completing the relief pattern forming steps S30 to S50, the applied photoresist 50 forms a conductive relief layer 21 exposed as a predetermined relief pattern 50 ′ and an intaglio pattern.

The pattern build-up step (S60 to S70) is performed by a semi-additive plating method, and is performed by laminating a metal on an intaglio pattern portion in which the embossed pattern 50 ′ of the circuit is not formed.

First, electrolytic plating using copper (Cu) is performed on the exposed conductor deposition layer 21 to form copper, thereby forming the first plating layer 20 (S60), and as the second plating layer 30 thereon. Nickel (Ni) is plated and laminated, and a wiring pattern is formed by plating gold (Au) as the third plating layer 40 as the outermost layer thereon (S70).

The second plating layer 30 is used to prevent corrosion resistance of the wiring pattern and diffusion of the underlying metal, and the third plating layer 40 protects the wiring pattern from the etching solution in the bonding process of the chip and the etching step (S90) described later. It is used as a register layer.

The subsequent process is a photoresist removing step (S80) and an etching step (S90), in which the photoresist layer formed by the relief pattern 50 'is removed (S80), and the remaining conductor deposition layer 21 is soft-etched. By removing (S90), a desired cross-sectional flexible printed circuit board is formed.

The above method is a manufacturing method for minimizing the puddle phenomenon in the etching process (S90) by using a thick conductor layer of 6 to 8 탆 thick in the prior art, while saving copper resources.

However, if the copper plating layer, which is the first plating layer 20 of the wiring pattern formed by the pattern build-up method, is exposed to air, the copper plating layer, which is formed by the pattern build-up method, may be oxidized and corroded when stored for a long time with the wiring pattern formed. .

Moreover, the problem in copper thin film formation is mentioned. As a method of depositing the metal conductor layer 21 on the insulating sheet 10, there are largely sputtering, casting, and lamination methods. Among them, the deposition by the sputtering method has high peel strength ( It is recognized as an effective method for securing peel strength and forming fine pitch by dimension stability, and the sputtering method was used in the above-described invention and the conventional flexible printed circuit manufacturing process.

However, although not shown in FIG. 5, even when the sputtering method is used to form the copper thin film, as shown in FIG. 6 to prevent a decrease in peeling strength when sputtering the copper thin film directly onto the insulating sheet 10. Likewise, before forming the copper deposition layer 21 by sputtering, it is necessary to first form the Ni-Cr alloy layer 21 'as a seed layer or a tie-coating layer.

As shown in FIG. 6, due to the presence of the seed layer 21 ′, the seed layer etching step (S91) by the use of a separate expensive etching solution is required as a post-process of soft etching (S90) on the copper deposition layer. In particular, in the case of forming a high-density wiring pattern having a spacing between the wiring patterns, that is, a pitch of 10 to 50 μm, the seed layer 21 ′ is not removed even though the seed layer etching step S91 is performed. There are many problems that cause a decrease in electrical insulation resistance between circuits, which greatly affects the production yield.

The present invention is to solve the above problems, the object is to suppress the puddling phenomenon, easy to form the ultra fine circuit pattern, to solve the problem of environmental problems and copper resources waste by minimizing the amount of etching, To provide a method of manufacturing a printed circuit board that can reduce the cost.

Method for manufacturing single-sided and double-sided flexible printed circuit boards to prevent oxidation of the wiring pattern when the copper plating layer used as the first plating layer of the wiring pattern is exposed to air for long-term storage and a metal wiring pattern having a structure that does not oxidize To provide.

In addition, an object of the present invention is to provide an economical manufacturing method that can shorten the process by eliminating the seed layer etching process by a conventional sputtering method in forming a copper foil laminated plate.

In addition, the purpose of the present invention is to eliminate the possibility of occurrence of a phenomenon in which the electrical insulation resistance decreases due to the presence of the remaining seed layer, and to increase the production yield in the process.

 In addition, by forming a thin metal conductor layer having a thickness of 1 to 4㎛ by a casting method, an object of the present invention is to provide a method for producing a single-sided and double-sided printed circuit board with high production yield and high reliability.

The present invention provides a method for manufacturing a single-sided and double-sided flexible printed circuit board for solving the above problems,

The method for manufacturing a single-sided flexible printed circuit board includes a flexible copper laminated board preparation step of preparing a flexible copper laminated board made of an insulating sheet having a metal conductor layer formed on one surface thereof; An embossed pattern forming step of applying a photoresist to the embossed circuit pattern on the metal conductor layer formed by preparing the flexible copper clad laminate and then performing exposure and development; A first plating layer forming step of forming a first plating layer on the metal conductor layer exposed by the relief pattern forming step through copper plating; A photoresist removing step of removing the photoresist relief pattern formed by the relief pattern forming step; Etching to remove the exposed metal conductor layers other than the first plating layer by soft etching; And a pattern building up step of sequentially plating the nickel plating layer as the second plating layer and the gold plating layer as the third plating layer on the first plating layer to stack wiring patterns.

Here, the step of preparing the flexible copper-clad laminate is performed by a casting method in which the mold is installed on the side of the metal conductor layer having a thickness of 1 to 4 μm, and the insulating base melt is applied to the upper surface of the metal conductor layer to be dried and cured. It is preferable to form a reliable wiring pattern by excluding the seed layer etching step by the conventional sputtering method.

In addition, the flexible copper-clad laminate preparation step of preparing a flexible copper-clad laminate consisting of an insulating sheet with a metal conductor layer formed on one surface; An embossed pattern forming step of applying a photoresist to the embossed circuit pattern on the metal conductor layer formed by preparing the flexible copper clad laminate and then performing exposure and development; A first plating layer forming step of forming a first plating layer on the metal conductor layer exposed by the relief pattern forming step through copper plating; A pattern building-up step of laminating wiring patterns by sequentially plating a nickel plating layer as a second plating layer and a gold plating layer as a third plating layer on the first plating layer; A photoresist removing step of removing the photoresist relief pattern formed by the relief pattern forming step; In the method of manufacturing a single-sided flexible printed circuit board for a tape carrier type semiconductor package including an etching step of removing the exposed metal conductor layer other than the first plating layer by soft etching, the step of preparing a flexible copper clad laminate is 1-4. The casting is installed on the side surface of the metal conductor layer having a thickness, and the casting method is applied to the upper surface of the metal conductor layer, followed by drying and curing to remove the seed layer etching step by the conventional sputtering method. It is preferable in forming a reliable wiring pattern.

In this case, the thickness of the first plating layer is preferably 5 to 12㎛ for the optimum characteristic display.

In addition, the method for manufacturing a double-sided flexible printed circuit board includes a hole forming step of forming a via hole in a flexible copper-clad laminate consisting of an insulating sheet having a conductor layer formed on both sides; A hole coating step of electrically connecting upper and lower surfaces of the flexible copper clad laminate by forming a copper plating layer by sputtering on the flexible copper clad laminate having the via hole formed thereon to coat the holes; An embossed pattern forming step of forming a circuit pattern by applying photoresist on both sides of the flexible copper clad laminate and performing exposure and development; A first plating layer forming step of forming a first plating layer on the double-sided conductor layer exposed by the relief pattern forming step through additional copper plating; A photoresist removing step of removing the remaining photoresist formed by the relief pattern forming step; Etching to remove the exposed conductor layers other than the first plating layer by soft etching; It is preferable to include a pattern build-up step of sequentially plating the first plating layer and the second plating layer nickel plating layer and the third plating layer gold plating layer to stack the wiring pattern to prevent oxidation of the first plating layer.

Here, the flexible copper-clad laminate is provided with a mold on the side of the first metal conductor layer having a thickness of 1 to 4㎛, apply an insulating base melt on the upper surface of the first metal conductor layer, and has a thickness of 1 to 4㎛ After stacking the second metal conductor layer, it is formed by a casting method performed by drying and curing the insulating base melt, thereby eliminating a seed layer etching step by a conventional sputtering method, and using a wiring pattern having high reliability and high production yield. It is preferable in forming.

In addition, the hole forming step of forming a via hole in a flexible copper foil laminated plate made of an insulating sheet having a conductor layer formed on both sides; A hole coating step of electrically connecting the upper and lower sides of the flexible copper foil laminated plate by forming a copper plating layer by sputtering on the flexible copper foil laminated plate on which the via hole is formed; An embossed pattern forming step of forming photosensitive circuit patterns by applying photoresist on both sides of the flexible copper clad laminate and performing exposure and development; A first plating layer forming step of forming a copper plating layer on the double-sided conductive layer exposed by the relief pattern forming step through additional copper plating; A pattern building-up step of laminating wiring patterns by sequentially plating a nickel plating layer, which is a second plating layer, and a gold plating layer, which is a third plating layer, on the first plating layer; A photoresist removing step of removing the photoresist relief pattern formed by the relief pattern forming step; In the method of manufacturing a double-sided flexible printed circuit board for a tape carrier type semiconductor package including an etching step of removing the exposed conductor layer other than the first plating layer by soft etching, the flexible copper clad laminate is 1 to 4㎛ thickness. After the mold is provided on the side of the first metal conductor layer, an insulating base melt is applied to the upper surface of the first metal conductor layer, and a second metal conductor layer having a thickness of 1 to 4 μm is laminated thereon, and then the insulating base melt It is preferable to form a reliable wiring pattern by excluding the seed layer etching step by a conventional sputtering method, which is formed by a casting method, which dries and cures the resin.

In this case, the thickness of the first plating layer is preferably 5 to 12㎛ for the optimum characteristic display.

In addition, the metal wiring pattern of the flexible printed circuit board for a tape carrier type semiconductor package according to the present invention is laminated on at least one surface of the insulating sheet in order of a copper plating layer as the first plating layer, a nickel plating layer as the second plating layer, and a gold plating layer as the third plating layer. In order to prevent the oxidation of the metal wiring pattern, the second plating layer and the third plating layer have a structure surrounding the top and side surfaces of the first plating layer.

According to the method of manufacturing a flexible printed circuit board according to the present invention, it is possible to suppress the puddle phenomenon according to the manufacturing of the flexible printed circuit board by the conventional etching process, to form an ultra fine circuit pattern, and to minimize the amount of etching. Reducing environmental problems and waste of copper resources and increasing productivity, resulting in cost savings.

In addition, a method for manufacturing single-sided and double-sided flexible printed circuit boards which can prevent oxidation of the wiring pattern when the copper plating layer used as the first plating layer of the wiring pattern is exposed to air for a long time and the metal wiring pattern formed using the same Can be provided.

In addition, by eliminating the seed layer etching process by the conventional sputtering method in forming the copper clad laminate, it is economical to shorten the process and eliminate the possibility of occurrence of a drop in electrical insulation resistance due to the presence of the remaining seed layer. It can provide a manufacturing method.

In addition, by forming a thin conductor layer having a thickness of 1 to 4㎛ by a casting method, there is an advantage that can provide a method for manufacturing a reliable single-sided and double-sided flexible printed circuit board.

Hereinafter, the configuration and operation of the flexible printed circuit board according to the present invention will be described with reference to the accompanying drawings.

A first preferred embodiment of the present invention relates to a method for manufacturing a single-sided flexible printed circuit board according to the present invention, and a second preferred embodiment to a method for manufacturing a flexible copper foil laminate (FCCL) of a flexible printed circuit board according to the present invention. The third embodiment is a flow chart showing a method for manufacturing a double-sided flexible printed circuit board according to the present invention.

1 is a flowchart illustrating a method of manufacturing a single-sided flexible printed circuit board according to a first preferred embodiment of the present invention.

As shown in FIG. 1, the method of manufacturing a single-sided flexible printed circuit board according to a first exemplary embodiment of the present invention includes a flexible copper laminated board preparing step (S10), a pattern forming step (S20 to S40), and forming a first plating layer. A step S50, a photoresist removing step S60, an etching step S70, and a pattern build-up step S80 are performed.

Specifically, by attaching a metal conductor layer 21 such as copper to the insulating sheet 10 by a casting method or a sputtering method, a single-sided flexible copper layer (FCCL) is formed (S10), and the photoresist 50 is attached thereto. After coating (S20), placing the pattern mask 60 thereon, exposing (S30) and developing (S40), and plating and laminating a copper plating layer 22 on the exposed metal conductor layer 21 The first plating layer 20 including the entire layer 21 and the copper plating layer 22 is formed (S50), and the photoresist constituting the remaining relief pattern 50 'is removed (S60), and the first plating layer ( By removing the remaining conductor layer 21 other than the part laminated in the layer 20 by soft etching (S70), and laminating the second plating layer 30 and the third plating layer 40 by electroplating (S80). A method for manufacturing a single-sided flexible printed circuit board according to the present invention is performed.

The present invention has a technical feature in the formation of the wiring pattern in the first plating layer forming step (S60) to the pattern build-up step (S90) of the manufacturing method, this technical feature is the first of the wiring pattern among the problems of the prior art The copper plating layer used as the plating layer is applied to solve the problem of preventing the oxidation problem of the wiring pattern when exposed to air for a long time storage.

In addition, by eliminating the seed layer etching process among the problems of the prior art, to shorten the process and to eliminate the possibility of occurrence of a drop in electrical insulation resistance due to the presence of the remaining seed layer As another technical feature of the present invention, it is possible to perform the step of preparing a flexible copper clad laminate (S10) by a casting method rather than a sputtering method. This will be described in the second best embodiment, which will be described later. Hereinafter, technical features of the 'metal wiring pattern formation' will be described.

Conventional wiring pattern formation, as shown in Figure 5, improves the bonding between the nickel (Ni) plating layer and the chip used to achieve the corrosion resistance of the wiring pattern as the second plating layer 30 in the first plating layer 20 and After the electroplating and laminating the gold (Au) plating layer, which is a third plating layer to be used, the remaining photoresist relief pattern 50 'is removed, and the conductor layer 21 is etched and removed to form a wiring pattern. It was.

However, according to the method of manufacturing the wiring pattern, the copper plating layer, which is the first plating layer 20, is exposed to air, and thus, the first plating layer 20 is oxidized when stored for a long time. same.

The present invention is to solve this problem, the first plating layer 20 composed of the conductor layer 21 and the copper plating layer 22 by copper electroplating so as to have a thickness of 5 to 12㎛, preferably 8 to 10㎛ After the first plating layer forming step S60, the photoresist removing step S70 for removing the photoresist relief pattern 50 'is performed immediately, followed by the etching step S80 for removing the metal conductor layer by soft etching. Then, finally, a pattern build-up step (S90) of laminating the Ni plating layer, which is the second plating layer 30, and the Au plating layer, which is the third plating layer, by the electroplating method is performed.

Here, when the first plating layer 20 is 5 μm or less, since a resist layer for protecting the wiring pattern is not provided for the separate etching solution, etching with the etching solution proceeds, and the thickness of the first plating layer 20 is too high. Due to the lowering, the electroplating of the second plating layer 30 may not be performed smoothly, and the electrical resistance of the circuit is increased. When the thickness is 12 μm or more, the copper layer, which is the first plating layer 20, is formed so high that it is economical. There is a problem.

Further, forming the first plating layer 20 to a thickness of 5 to 12 μm, preferably 8 to 10 μm, is preferably 3 to 10 μm after the first plating layer 20 is etched by the etching solution. It is for maintaining the thickness of 6-8 micrometers.

The cross-section of the metal wiring pattern of the single-sided flexible printed circuit board formed through the insulation sheet preparation step (S10) to the pattern build-up step (S90) is shown in the enlarged drawing of the last of FIG. The upper and side surfaces of the 20 are formed to surround the second plating layer 30 and the third plating layer 40.

In the structure of the completed metal wiring pattern, each thickness for optimizing the characteristics is reduced by the first plating layer 20 by etching, and is formed to have a thickness of 6 to 8 μm, and the second plating layer 30 is formed. 0.1-2.5 micrometers and the 3rd plating layer 40 are formed in 0.1 micrometer.

The reason for this configuration is that in the prior art, the first plating layer 20 to the third plating layer 40 are sequentially stacked in the state where the photoresist relief pattern 50 'is present. Since the first plating layer 20 surrounds the side surface of the first plating layer 20, the plating solution of the remaining second plating layer 30 and the third plating layer 40 may not be attached to this portion by the electroplating method. After plating the first plating layer 20, the photoresist relief pattern 50 ′ is removed, and the metal conductor layer 21 is removed by etching, so that the second plating layer 30 is formed on the side of the first plating layer 20. This is because the third plating layer 40 may be attached to form a plating layer.

Therefore, when the copper plating layer constituting the first plating layer 20 which is easy to be oxidized is protected by Ni and the third plating layer 40 Au, which is not easily oxidized in air, is stored for a long time. Also, problems such as short circuit of wiring patterns due to oxidation and corrosion can be solved.

However, even if the metal wiring pattern formation method is used, when the flexible copper clad laminate preparation step S10 is performed by the sputtering method, the fine wiring patterns of 10 to 50 μm are etched in the process of etching the metal conductor layer 21. If the etching solution does not sufficiently penetrate between the gaps, the seed layer, which is a Ni-Cr alloy existing under the metal conductor layer 21, may not be properly etched.

Thus, when electroplating the second plating layer 30 and the third plating layer 40 in the state that the seed layer (21 'shown in FIG. 6) is not removed, the plating solution is also applied to the remaining seed layer 21'. This may cause the phenomenon that the electrical insulation resistance is reduced due to the energization between the metal wiring patterns.

According to the method of manufacturing the flexible circuit board according to the second preferred embodiment of the present invention described later, since the flexible printed circuit without the seed layer can be provided, such a problem can be overcome, and further, the fine wiring pattern It is possible to form a circuit.

2 is a view showing a method of manufacturing a flexible copper clad laminate (FCCL) of a flexible printed circuit board according to a second preferred embodiment of the present invention.

The second best embodiment of the present invention shown in FIG. 2 is a method of manufacturing a flexible copper foil laminate by a casting method that can be applied to both single-sided and double-sided printed circuit boards.

The second best embodiment is a single-sided and double-sided flexible printed circuit board of the conductor deposition step (S20) of the conventional semi-enerative method described in FIG. 5, the first best embodiment and the third best embodiment to be described later. It is applied directly to the flexible copper foil laminated plate preparation step (S10, S100) of the manufacturing method.

First, the conductor layer 21 provided to manufacture the flexible copper foil laminate plate by the casting method is 1 to 4 ㎛ thick, preferably 2 to 3 ㎛ thick copper having a surface in contact with the insulating base 10 Made of a metal conductor layer.

Here, the thickness of the metal conductor layer 21 is limited, and when the thickness of the metal conductor layer 21 is 4 μm or more, it is difficult to prevent a pudling phenomenon, which is one object of the present invention. This is because when the thickness is less than 1 µm, there is a difficulty in forming the copper plated layer 22 as the wiring pattern and the workability is deteriorated.

When the metal conductor layer 21 is prepared, a mold 23 is formed in the form of the edge of the conductor layer 21 with the metal conductor layer 21 facing upward, and the insulating sheet 10 is placed thereon. The polyimide melt, which is a material of), is poured directly or applied by a rolling method.

FCCL for double-sided flexible printed circuits are two identical plate-shaped metal conductor layers, utilizing a first metal conductor layer and a second metal conductor layer, and installing a mold on the side of the first metal conductor layer having a thickness of 1 to 4 μm. The insulating base melt is applied to the upper surface of the metal conductor layer, and a second metal conductor layer having the same thickness is laminated thereon, and then the casting is performed by drying and curing the insulating base melt.

After the coating process, the molten liquid of the insulating sheet 10 is dried and cured to form a flexible copper clad laminate.

In addition to the above method, a peelable copper thin film may be utilized. The conductive layer 21 is formed by laminating a carrier foil made of a release material made of a release adhesive and a metal material formed on the opposite side to which the insulating sheet 10 melt is poured, and a metal material. It has a structure that ensures a thickness that can withstand the temperature of the melt.

The peelable copper thin film is used by injecting a melt of the insulating sheet 10, drying and curing, and then peeling the release material and the metal foil from the surface of the conductor layer 21, and finally, the insulating sheet 10 The FCCL consisting of the conductor layer 21 is obtained on the phase. This method is used when the conductor layer 21 is too thin to support the melt of the insulating sheet 10 and may be deformed.

The problem solved by the second best embodiment is, first, since it is not necessary to form the seed layer (Seed layer), which is essentially introduced in the conventional sputtering method shown in Fig. 6 after which the seed layer etching step (S91) is excluded In the high-density wiring pattern having a pitch of 10 to 50 µm, the electrical insulation resistance between the wires due to the existence of the remaining seed layer that is not removed despite the seed layer etching step (S91) of FIG. It is to provide a method for producing FCCL that can eliminate this deterioration phenomenon.

In other words, through the second best embodiment, the process can be simplified, the economical effect of reducing the expensive etching solution used to remove the seed layer can be enjoyed, and a more efficient high density wiring pattern can be realized. There is an advantage.

Next, a method for manufacturing a double-sided flexible circuit board according to a third best embodiment of the present invention will be described with reference to FIG. 3.

3 is a flowchart illustrating a method of manufacturing a double-sided flexible printed circuit board according to a third preferred embodiment of the present invention.

As shown in FIG. 3, the overall process of the flexible printed circuit board of the double-sided flexible printed circuit board according to the present invention is a flexible copper-clad laminate preparation step (S100), hole forming step (S200), hole coating step (S300), embossed pattern forming step (S410) To S420), the first plating layer forming step (S500), the photoresist removing step (S600), the etching step (S700), and the pattern building up step (S800), and the detailed process is as follows.

As a first step, in order to impart conductivity to both surfaces of the insulating sheet 100 made of polyimide as a base film having a thickness of 25 μm, 1 to 4 by the casting method described in the second embodiment of the present invention. A flexible copper clad laminate (FCCL) having a conductor layer 210 composed of a first metal conductor layer 211 and a second metal conductor layer 212 having a thickness of preferably 2 to 3 μm is prepared (flexible copper foil). Laminate preparation step, S100).

The step of preparing a flexible copper clad laminate (S100) is a sputtering method, after depositing a metal conductor layer having a thickness of 0.1 to 0.5㎛ by sputtering, respectively, the first metal conductor layer 211 having a thickness of 1 to 4㎛ and The conductive layer 210 made of the second metal conductor layer 212 is formed by forming FCCL by the electroplating method.

Here, the reason for limiting the thickness of the metal conductor layer 210 is the same as described in the step (S10) of the flexible copper clad laminate of the first best embodiment of the present invention.

Next, a hole forming step (S200) of forming a via hole 600 in the flexible copper foil laminated plate prepared by the flexible copper laminated plate preparation step (S100) is performed.

The purpose of forming the via hole 600 is to conduct electricity between wiring patterns formed on the upper and lower surfaces of the flexible copper clad laminate, and the via hole 600 forms a through hole (PTH) penetrating through the flexible copper laminate, or in a thickness direction. As a result, blind bead holes BVH may be formed to form only a part of the holes. 3 illustrates the application of through holes.

Specifically, in the case of forming the through hole, the blind metal hole penetrates through the first metal conductor layer 211, the polyimide layer 100, and the second metal conductor layer 212 sequentially. In this case, a hole reaching the lower portion of the first metal conductor layer 211 and the insulating sheet 100 is formed to leave the second metal conductor layer 212. In the hole forming method, all three types of laser processing methods, chemical etching methods, and mechanical punching presses can be used.

Hole coating step (S300) is a hole for electrically connecting the upper and lower surfaces of the flexible copper-clad laminate by forming at least a portion of the hole by forming a plating layer by an electroless plating method on the substrate on which the hole is formed by the hole forming step (S200) The coating step (S300) may be performed, or the hole coating step (S300) by the sputtering method described below may be applied.

The hole coating step (S300) by the sputtering method may include copper on the front surface of the via hole 600 formed in the hole forming step (S200) and the first metal conductor layer 211 or the second metal conductor layer 212. Or by coating the copper deposition layer 200 'using a copper alloy sputtering method.

The hole coating step (S300) completely fills the hole 600 by copper electroplating on the copper deposition layer 200 ′ or forms a copper layer having a thickness of 1 to 4 μm on the copper deposition layer 200 ′. It may be performed by further comprising a copper electroplating step.

Next, the photoresist 500 is applied (S410), and the relief pattern forming step (S400) of exposing (S420) and developing (S430) the conventional method is performed.

Subsequently, similarly to the method of manufacturing the thin single-sided flexible printed circuit board, the double-sided flexible printed circuit board is also removed from the photoresist removing the first plating layer forming step S500 and the remaining photoresist relief pattern 500 '. Step (S600), the etching step (S700) for soft etching the metal conductor layer 210 is removed, the Ni plating layer as the second plating layer 300 is laminated on the already formed first plating layer 200, the third plating layer In order to prevent the oxidation of the copper plating of the first plating layer 200 by performing the process in the pattern building-up step (S800) of stacking the Au plating layer as (400).

In other words, in the first plating layer forming step S500, the copper plating layer 220 is laminated by additionally performing electroplating on the conductive layer 210a forming the wiring pattern exposed by the relief pattern forming step S400. This is performed by forming the first plating layer 200 having a thickness of 5 to 12 μm, and then, as described above, the photoresist removing step S600, the etching step S700, and the pattern building up step S800 are performed. A metal wiring pattern having the same shape as that of the single-sided flexible printed circuit board of the first preferred embodiment is completed.

Hereinafter, the characteristics change when the wiring pattern of the flexible printed circuit manufactured by the above-described manufacturing method is applied will be described with reference to Examples and Comparative Examples.

Example  One

In constructing the wiring pattern according to the manufacturing method of the cross-sectional flexible printed circuit board, which is applied together with the first and second best embodiments of the present invention, the Cu metal conductor layer 21 having a thickness of 2 μm by the casting method. The FCCL formed by forming the insulating sheet 10 having a thickness of 25 μm thereon was prepared, the photoresist 50 was applied on the metal conductor layer 21, and the exposure and development were performed. The copper plating layer 22 was plated on the formed metal conductor layer 21 so that the overall thickness of the first plating layer 20 was 9 μm, the photoresist relief pattern 50 ′ was removed, and then the metal conductor layer 21 was removed. ) Is removed by soft etching, and the Ni plating is deposited by plating the Ni alloy to a thickness of 0.2 μm as the second plating layer 30, and Au and 0.1 Au are respectively plated and laminated on the third plating layer 40 which protects the Ni alloy. To form a metal wiring pattern As, which resulted in the completion of the cross-section flexible printed circuit board.

Example 2

As a method according to the first preferred embodiment of the present invention, in forming the FCCL, the process is performed by the same method as in Example 1 except that the sputtering method and a separate seed layer etching step are added. A single-sided flexible printed circuit board was prepared.

Example 3

As a method according to a second preferred embodiment of the present invention, an FCCL formed by forming an insulating sheet 10 having a thickness of 25 μm on a Cu metal conductor layer 21 having a thickness of 2 μm by the casting method is provided, and a wiring pattern is provided. In forming the first plating layer 20, the second plating layer 30, and the third plating layer 40 by successively plating and laminating, after removing the photoresist embossed pattern 50 ', the metal conductor layer ( 21) was removed by soft etching, and the remainder was processed in the same manner as in Example 1 to prepare a cross-sectional flexible printed circuit board.

Comparative example

According to the conventional method of manufacturing a single-sided flexible printed circuit board, in forming a wiring pattern, FCCL is provided by a sputtering method, and the first plating layer 20, the second plating layer 30, and the third plating layer 40 are formed. After plating and laminating successively, the photoresist relief pattern 50 'was removed, and then the metal conductor layer 21 was removed by soft etching, and the remainder was subjected to the process by the same method as in Example 1 to provide ductility. A printed circuit board was manufactured.

The physical properties of the prepared semiconductor substrate samples were evaluated. The evaluation items are as follows, and the evaluation results are summarized in <Table 1>.

Patterning stability

Based on IPC ™ 650 2.2.4, the difference in dimensions before and after etching and heating of the sample was measured.

Peel strength

Peel strength of Cu per unit area was measured based on IPC ™ 640 2.4.9.

Surface roughness

Atomic Force Microscope (AFM) was used to measure the desired level of surface roughness.

Insulation Resistance

After applying a 500V DC voltage between electrically independent circuits for 1 minute, the insulation resistance between adjacent circuit patterns was measured. In the case of 100 MΩ as an evaluation criterion, the evaluation was satisfactory.

Withstand voltage

When AC 500V was applied for 1 minute between electrically independent circuits, it was evaluated as being good without a short circuit or dielectric breakdown.

Flex resistance

It was tested by rotating 20 times at 135.5 ° C with R = 0.38mm in 500g strength, and there was no crack or disconnection phenomenon of copper foil, and it was evaluated as excellent if there were no functional and electrical problems.

Corrosion resistance

Tested according to KS M 8012 Neutral Salt Spray Test, the concentration of sodium chloride was 40g / l for sodium chloride, compressed air pressure was 1.2kgf / cm2, sprayed amount was 1.51ml / 80cm3 / h, air saturation The group temperature was 47 ° C, the brine tank temperature was 35 ° C, and the test bath temperature was 35 ° C. Crack resistance was evaluated as excellent when the resistance change rate was within 10% and there was no short circuit or insulation breakdown.

Thermal shock

The test was carried out with a temperature change of 10 cycles within 5 minutes at -55 ° C to room temperature (30 minutes) and again at room temperature to 120 ° C (30 minutes), and the resistance change rate was within 10%. If there was no structural abnormality, the evaluation was good.

Moisture resistance

After 96 hours in 60 ℃ and 90 ~ 95% humidity, it was measured after 1 ~ 2 hours at room temperature (15 ~ 35 ℃). No abnormalities in appearance and structure, insulation resistance is more than 10 ohm and resistance change rate is less than 10%. It evaluated as good.

Heat resistance

After 96 hours in the range of 85 ℃ to 2 ℃, it was measured after 1 to 2 hours at room temperature. It was evaluated that it was satisfactory if there were no abnormalities in appearance / structure, insulation resistance was 10 or more and resistance change rate was within 10%.

TABLE 1

Kinds pitch Composition and Thickness of Cu Layer of FCCl  Seed layer etching required  Patterning stability  Adhesion  Surface roughness  Insulation Resistance  Withstand voltage  Flex resistance  Corrosion resistance  Thermal shock  Moisture resistance  Heat resistance  Remarks Sputtering layer Conductor layer Example 1   25 μm  - 2㎛ Unnecessary ⊙ ⊙ ⊙ ⊙ ⊙ ⊙ ⊙ ⊙ ⊙ ⊙ Process Simplification Example 2  0.2 μm 2㎛ need △ ⊙ ⊙ △ ⊙ ⊙ ⊙ ⊙ ⊙ ⊙ Process addition Example 3  - 2㎛ Unnecessary ⊙ ⊙ ⊙ △ △ ⊙ Ｘ △ Ｘ ⊙ Process Simplification Comparative example  0.2 2㎛ need △ ⊙ ⊙ △ △ ⊙ Ｘ △ Ｘ ⊙ Process addition

⊙: Excellent ○: Good △: Normal Ｘ: Poor

As shown in Table 1, Example 1 showed excellent evaluation results in all evaluation items, and in Example 2, normal evaluation results were found in terms of patterning stability and insulation resistance. The results showed poor evaluation in corrosion resistance and moisture resistance.

These evaluation results show that the seed layer etching step is not required when the casting method is applied, and exhibits superior characteristics in terms of patterning stability and insulation resistance than forming a flexible copper foil laminate by the sputtering method. .

In addition, when the wiring pattern is formed according to the wiring pattern forming method according to the present invention, it can be seen that the corrosion resistance and the moisture resistance of the wiring pattern can be significantly improved as previously predicted.

The foregoing has been described in detail with reference to preferred embodiments of the present invention. However, the scope of the present invention is not limited to the above embodiments, but may be embodied in various forms of embodiments within the appended claims. Without departing from the gist of the invention as claimed in the claims, any person skilled in the art to which the invention pertains is considered to be within the scope of the claims of the invention to the various possible modifications possible.

       1 is a flowchart illustrating a method of manufacturing a single-sided flexible printed circuit board according to a first preferred embodiment of the present invention.

2 is a view showing a method of manufacturing a flexible copper clad laminate (FCCL) of a flexible printed circuit board according to a second preferred embodiment of the present invention.

3 is a flowchart illustrating a method of manufacturing a double-sided flexible printed circuit board according to a third preferred embodiment of the present invention.

4 is a flowchart illustrating a method of manufacturing a conventional single-sided flexible printed circuit board.

5 is a flowchart illustrating a method of manufacturing a conventional cross-sectional flexible printed circuit board.

6 is a flowchart illustrating a method of manufacturing a flexible copper clad laminate by a conventional sputtering method.

* Description of the symbols for the main parts of the drawings *

10: insulating sheet 20: first plating layer (copper plating layer)

21: conductor layer 22: copper plating layer

30: second plating layer (Ni plating layer)

40: third plating layer (gold plating layer) 50: photoresist

50 ': photoresist relief pattern 60: pattern mask

100: insulating sheet 210: conductor layer

210a: wiring pattern conductor layer 211: first metal conductor layer

212: second metal conductor layer 220: copper plating layer

230: filled copper plating layer 300: second plating layer (Ni plating layer)

400: third plating layer (gold plating layer) 500: photoresist

500 ': photoresist embossed pattern

Claims (9)

In the method of manufacturing a single-sided flexible printed circuit board for a tape carrier type semiconductor package, A casting sheet is formed on the side of the metal conductor layer having a thickness of 1 to 4 μm, and is formed of an insulating sheet having a metal conductor layer formed on one surface by casting and drying by applying an insulating base melt on the upper surface of the metal conductor layer. A flexible copper clad laminate preparation step of preparing a flexible copper clad laminate; An embossed pattern forming step of applying a photoresist to the embossed circuit pattern on the metal conductor layer formed by preparing the flexible copper clad laminate and then performing exposure and development; A first plating layer forming step of forming a first plating layer on the metal conductor layer exposed by the relief pattern forming step through copper plating; A photoresist removing step of removing the photoresist relief pattern formed by the relief pattern forming step; Etching to remove the exposed metal conductor layers other than the first plating layer by soft etching; And a pattern build-up step of laminating wiring patterns by sequentially plating a nickel plating layer as a second plating layer and a gold plating layer as a third plating layer on the first plating layer. delete A step of preparing a flexible copper clad laminate that prepares a flexible copper clad laminate formed of an insulating sheet having a metal conductor layer formed on one surface thereof; An embossed pattern forming step of applying a photoresist to the embossed circuit pattern on the metal conductor layer formed by preparing the flexible copper clad laminate and then performing exposure and development; A first plating layer forming step of forming a first plating layer on the metal conductor layer exposed by the relief pattern forming step through copper plating; A pattern building-up step of laminating wiring patterns by sequentially plating a nickel plating layer as a second plating layer and a gold plating layer as a third plating layer on the first plating layer; A photoresist removing step of removing the photoresist relief pattern formed by the relief pattern forming step; A method of manufacturing a single-sided flexible printed circuit board for a tape carrier type semiconductor package comprising an etching step of removing an exposed metal conductor layer other than the first plating layer by soft etching. The flexible copper-clad laminate preparation step is performed by a casting method in which a mold is installed on the side of the metal conductor layer having a thickness of 1 to 4 μm and the insulating base melt is applied to the upper surface of the metal conductor layer to dry and harden. Method of manufacturing a single-sided flexible printed circuit board. The method according to claim 1 or 3, The thickness of the first plating layer is a manufacturing method of a cross-section flexible printed circuit board, characterized in that 5 to 12㎛. In the manufacturing method of the double-sided flexible printed circuit board for tape carrier type semiconductor package, A mold was provided on the side of the first metal conductor layer having a thickness of 1 to 4 μm, and an insulating base melt was applied to the upper surface of the first metal conductor layer, and a second metal conductor layer having a thickness of 1 to 4 μm was laminated thereon. A hole forming step of forming a via hole in a flexible copper foil laminated plate made of an insulating sheet having a conductor layer formed on both surfaces thereof, which is formed by casting, drying and curing the insulating base melt; A hole coating step of electrically connecting the upper and lower sides of the flexible copper foil laminated plate by forming a copper plating layer by sputtering on the flexible copper foil laminated plate on which the via hole is formed; An embossed pattern forming step of forming photosensitive circuit patterns by applying photoresist on both sides of the flexible copper clad laminate and performing exposure and development; A first plating layer forming step of forming a first plating layer on the double-sided conductor layer exposed by the relief pattern forming step through additional copper plating; A photoresist removing step of removing the photoresist relief pattern formed by the relief pattern forming step; Etching to remove the exposed conductor layers other than the first plating layer by soft etching; And a pattern build-up step of laminating a wiring pattern by sequentially plating the nickel plating layer, which is the second plating layer, and the gold plating layer, which is the third plating layer, on the first plating layer. delete A hole forming step of forming a via hole in a flexible copper foil laminated plate made of an insulating sheet having conductor layers formed on both surfaces thereof; A hole coating step of electrically connecting the upper and lower sides of the flexible copper foil laminated plate by forming a copper plating layer by sputtering on the flexible copper foil laminated plate on which the via hole is formed; An embossed pattern forming step of forming photosensitive circuit patterns by applying photoresist on both sides of the flexible copper clad laminate and performing exposure and development; A first plating layer forming step of forming a copper plating layer on the double-sided conductive layer exposed by the relief pattern forming step through additional copper plating; A pattern building-up step of laminating wiring patterns by sequentially plating a nickel plating layer, which is a second plating layer, and a gold plating layer, which is a third plating layer, on the first plating layer; A photoresist removing step of removing the photoresist embossed pattern formed by the embossed pattern forming step; and an etching step of removing an exposed conductor layer other than the first plating layer by soft etching, for both sides of the tape carrier type semiconductor package. In the method of manufacturing a flexible printed circuit board, The flexible copper-clad laminate is provided with a mold on the side of the first metal conductor layer having a thickness of 1 to 4 μm, and an insulating base melt is applied to the upper surface of the first metal conductor layer, and the second metal having a thickness of 1 to 4 μm thereon. A method of manufacturing a double-sided flexible printed circuit board, which is formed by casting, after laminating conductor layers, and drying and curing the insulating substrate melt. The method according to claim 5 or 7, The thickness of the first plating layer is a manufacturing method of a double-sided flexible printed circuit board, characterized in that 5 to 12㎛. delete

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