KR20140041080A - Flexible circuit clad laminate, printed circuit board using it, and method of manufacturing the same - Google Patents

Abstract

The purpose of the present invention is to provide a flexible circuit copper-clad laminate with excellent etching characteristics, peel strength, and curl characteristics. The flexible circuit copper-clad laminate according to the present invention includes a polymer film, a tie-coat layer formed on at least one surface of the polymer film, and a copper (Cu) layer formed on the tie-coat layer. The tie-coat layer is composed of an alloy containing 10.0-70.0 wt% of molybdenum (Mo), 0.5-20.0 wt% of cobalt (Co), and a remaining part of nickel (Ni).

Description

TECHNICAL FIELD [0001] The present invention relates to a flexible circuit clad laminate, a printed circuit board using the same, and a method of manufacturing the same.

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a flexible circuit copper-clad laminate, a printed circuit board using the same, and a manufacturing method thereof, and more particularly to a flexible circuit copper-clad laminate having excellent etchability, high-temperature peel strength, ≪ / RTI >

A printed circuit board (PCB) is a wiring diagram that expresses the electrical wiring to connect various components according to the circuit design. It serves to connect or support various components. In particular, the demand for printed circuit boards has increased with the development of electronic devices such as notebook computers, mobile phones, PDAs, compact video cameras, and electronic notebooks. Furthermore, the above electronic devices are becoming increasingly smaller and lighter in weight as portability is emphasized. Therefore, printed circuit boards are being further integrated, miniaturized, and lightweight.

The printed circuit board may include a rigid printed circuit board, a flexible printed circuit board, a rigid-flexible printed circuit board coupled to the rigid printed circuit board, and a rigid-flexible printed circuit board similar to a multi- It is divided into printed circuit board. In particular, flexible circuit clad laminate (FCCL), which is a raw material of flexible printed circuit boards, is used in digital home appliances such as mobile phones, digital camcorders, notebooks, and LCD monitors, Demand is rapidly increasing.

The flexible circuit copper-clad laminate is a laminate of a polymer film layer and a metal conductive layer, and is flexible. Flexible circuit pendant side plates are used in parts of electronic equipment or electronic equipment that require flexibility and flexibility, contributing to miniaturization and weight reduction of electronic equipment.

Conventional flexible circuit copper-clad laminates related to this technology are largely divided into a method of applying a polyimide resin to a copper foil and a method of depositing copper on a polymer film. Particularly, the copper deposition method can form a very thin copper film.

The flexible circuit copper-clad laminate of the evaporation type is manufactured by forming a tie-coat layer on a polymer film by sputtering method and then electrolytically plating copper while continuously passing the tiecoat layer through a copper electrolytic plating bath.

In the fabricated flexible circuit copper-clad laminate, a semiconductor chip, an electric element, or the like is mounted on a circuit after the circuit is formed, and a miniaturization, a multi-pin, and a narrow pitch of a driver IC are rapidly proceeding . Accordingly, there is a demand for a flexible circuit copper-clad laminate having excellent physical properties such as an etching property, a peel strength, and a curl characteristic.

However, the existing flexible circuit copper-clad laminate mainly using NiCr alloy, NiMoV alloy, NiMoTi alloy, or the like as the tie coat layer does not satisfy such a demand.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a flexible circuit copper-clad laminate which has been developed in consideration of the above-described conventional techniques and has excellent physical properties such as an etching property, a high-temperature peeling strength, and a peeling strength at room temperature.

According to another aspect of the present invention, there is provided a flexible circuit copper clad laminate comprising: a polymer film; a tiecoat layer formed on at least one side of the polymer film; and a copper (Cu) Wherein the tie coat layer contains 10.0 wt% to 70.0 wt% of molybdenum (Mo), 0.5 wt% to 20.0 wt% of cobalt (Co), and the balance of nickel (Ni) Alloy.

The interface region of the tie coat layer in contact with the polymer film may have an oxygen content of 2.5at% or less.

The corrosion current density of the tie coat layer may be 0.6 mA / cm ^{2 or} more.

The thickness of the tie coat layer may be between 5 nm and 35 nm.

The polymer film may be made of at least one of a thermosetting resin, a thermoplastic resin, a polyester resin, a polyimide resin, a condensation polymer, or a mixture of at least two of the above.

The polymer film may be a polyimide resin.

Wherein the copper layer comprises: a copper seed layer formed on the tie coat layer; And a copper coating layer formed on the copper seed layer.

The thickness of the copper seed layer may be 20 nm to 100 nm.

The thickness of the copper coating layer may be 5 탆 to 15 탆.

According to another aspect of the present invention, there is provided a flexible circuit board, including a wiring pattern formed on a copper layer of the flexible circuit copper-clad laminate.

According to an aspect of the present invention, there is provided a method of fabricating a flexible circuit copper-clad laminate, comprising: (a) preparing a polymer film; (b) a tie consisting of an alloy containing molybdenum (Mo), 0.5 wt% to 20.0 wt% of cobalt (Co) and the balance of nickel (Ni) in an amount of 10.0 wt% to 70.0 wt% Forming a coat layer; And (c) forming a copper layer on the tie coat layer; .

The step (a) may include a step of removing the contaminants on the surface and modifying the surface by plasma-treating the polymer film.

The step (b) may be a step of depositing a tie coat layer on the polymer film by using a sputtering method.

In the step (b), an interface region of the tie coat layer in contact with the polymer film may have an oxygen content of 2.5at% or less.

The step (c) may be a step of forming a copper seed layer on the tie coat layer and then forming a copper coating layer on the copper seed layer.

The copper seed layer is deposited on the tie coat layer by sputtering, and the copper coating layer may be plated on the copper seed layer by electrolytic plating.

According to another aspect of the present invention, there is provided a method of manufacturing a flexible circuit board, including: fabricating the flexible circuit copper-clad laminate; And forming a wiring pattern on the copper layer of the flexible circuit copper clad laminate.

According to the present invention, the alloy constituting the tie-coat layer formed on the polymer film includes nickel (Ni), molybdenum (Mo), and cobalt (Co), and the content ratio of the metal contained in the alloy, The effect of improving the physical properties of the flexible circuit copper-clad laminate is obtained by controlling the content of oxygen and the like.

BRIEF DESCRIPTION OF THE DRAWINGS The accompanying drawings, which are incorporated in and form a part of the specification, illustrate preferred embodiments of the invention and, together with the description of the invention given above, serve to further the understanding of the technical idea of the invention. And should not be construed as limiting.
1 is a sectional view of a flexible circuit copper-clad laminate according to the present invention.
2 is a flowchart showing a method of manufacturing a flexible circuit copper-clad laminate according to the present invention.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. Prior to this, terms and words used in the present specification and claims should not be construed as limited to ordinary or dictionary terms, and the inventor should appropriately interpret the concept of the term appropriately in order to describe its own invention in the best way. It should be interpreted in accordance with the meaning and concept consistent with the technical idea of the present invention based on the principle that it can be defined. Therefore, the embodiments described in this specification and the configurations shown in the drawings are merely the most preferred embodiments of the present invention and do not represent all the technical ideas of the present invention. Therefore, It is to be understood that equivalents and modifications are possible.

1 and 2, a flexible circuit copper-clad laminate according to the present invention and a method of manufacturing the same will be described.

FIG. 1 is a cross-sectional view of a flexible circuit copper-clad laminate according to the present invention, and FIG. 2 is a flowchart showing a method of manufacturing a flexible circuit copper-clad laminate according to the present invention.

1 and 2, a flexible circuit copper-clad laminate according to the present invention comprises a polymer film 1, a tie coat layer 2, and a copper layer 3 sequentially laminated.

The polymer film (1) is a film of a single layer or a multiple layer composed of at least one of a thermosetting resin, a thermoplastic resin, a polyester resin, a polyimide resin, a condensation polymer or a mixture of at least two or more thereof. The polymer film 1 may be made of a filler (or no filler), woven glass, non woven glass and / or other textile materials.

Examples of the thermosetting resin include phenol resin, phenol aldehyde resin, furan resin, aminoplast resin, alkyd resin, allyl resin, epoxy resin, epoxy prepreg, polyurethane resin, thermosetting polyester resin, Can be used. Examples of the thermoplastic resin include polyethylene, polypropylene, ethylene / vinyl copolymer, and ethylene acrylic acid copolymer. As the polyester resin, those prepared from a dihydric aliphatic and aromatic carboxylic acid and a diol or triol can be used. The polyimide resin is particularly useful because it is obtained by bringing a tetrabasic acid dianhydride into contact with an aromatic diamine to yield a polyamic acid and then converting it into heat and / or a polymeric weight linear polyimide . As the condensation polymer, polyamide, polyether imide, polysulfone, polyethersulfone, polybenzazole, aromatic polysulfone and the like can be used. The polymer film (1) is subjected to a pretreatment process before depositing the tie coat layer (2). That is, the polymer film 1 is plasma-treated prior to the formation of the tie coat layer 2 to remove contaminants on the surface and modify the surface.

The tie coat layer 2 is formed on at least one surface of the both surfaces of the polymer film 1 and is made of an alloy containing molybdenum (Mo), cobalt (Co), and the remainder nickel (Ni). The tie coat layer 2 may be deposited on the polymer film 1 by a sputtering method, which is a kind of dry plating method, and is preferably formed to a thickness of about 5 nm to 35 nm. When the thickness of the tie coat layer 2 is less than 5 nm, the peeling strength may be lowered at the time of etching for forming the wiring pattern. If the thickness is more than 35 nm, the etching process may not be easy.

The content of molybdenum constituting the alloy is preferably about 10.0 wt% to 70.0 wt% with respect to the total weight of the alloy. When the content of the molybdenum is less than 10.0 wt%, there is a problem that the etching property is poor, that is, the corrosion current density value is measured too low (less than 0.6 mA / cm ² ). If the corrosion current density is measured to be less than 0.6 mA / cm ² , residues may remain at the time of etching, which may cause a short circuit between the wirings due to ion migration. On the contrary, when the content of the molybdenum exceeds 70.0 wt%, the tie coat layer 2 may be inferior in workability. Here, when the workability of the tie coat layer 2 is deteriorated, it means that the brittleness is strengthened. Therefore, when the workability is low, the target may be broken at the time of sputtering.

The content of cobalt present in the alloy is preferably about 0.5 wt% to 20 wt%. When the content of the cobalt is less than 0.5 wt%, the peeling strength at room temperature of the flexible circuit copper clad laminate becomes too weak. On the contrary, when the content of the cobalt exceeds 20 wt%, there is a problem that the high-temperature peel strength becomes too weak. In the case where the peel strength falls below a certain value (high temperature: less than 0.4 kgf / cm and room temperature: less than 0.6 kgf / cm), the peeling phenomenon (polymer film- Tie coat ") occurs.

Therefore, in order to obtain a flexible circuit copper-clad laminate having excellent etching properties, high temperature / room temperature peel strength characteristics and workability, the content range of molybdenum contained in the alloy constituting the tie coat layer 2 is limited to 10 wt% to 70 wt% Is limited to 0.5 wt% to 20 wt%.

On the other hand, the oxygen content of the tie coat layer 2 can be controlled by controlling the degree of vacuum of the chamber during the sputtering process for forming the tie coat layer 2. In the tie coat layer 2, the polymer film 1 ) Is preferably 2.5at% (atomic percent) or less. This is because when the oxygen content in the interfacial region of the tie coat layer 2 exceeds 2.5 at%, a phenomenon (in particular, less than 0.4 kgf / cm) in which the high-temperature peel strength characteristic is lowered is generated. On the other hand, as the oxygen content in the interface region approaches 0 at%, the high-temperature peel strength characteristics can be further improved.

The copper layer 3 is formed on the tie coat layer 2 and includes a copper seed layer 3a and a copper coating layer 3b. The copper seed layer 3a is formed on the tie coat layer 2 by sputtering to have a thickness of approximately 10 nm to 100 nm.

The coating layer 3b is a copper layer formed by electrolytic plating on the copper seed layer 3a and is preferably formed to a thickness of about 5 탆 to 15 탆 and more preferably a thickness of 8 탆 to 8.5 탆 .

As described above, the flexible circuit copper-clad laminate according to the present invention includes a step S1 of preparing a pretreated polymer film 1, a step S2 of forming a tie coat layer 2, a step of forming a copper seed layer 3a, (S3) of forming a copper coating layer (3) and forming a copper coating layer (3b) (S4).

The flexible circuit copper-clad laminate produced according to this manufacturing method of the present invention can have excellent physical properties by adjusting the content of nickel, molybdenum and cobalt contained in the tie coat layer 2 to a certain range. In addition, the flexible circuit copper-clad laminate can have excellent physical properties by adjusting the oxygen content of the interface region of the tie coat layer 2 in contact with the polymer film 1 to a certain range or less.

Meanwhile, a desired wiring pattern can be formed by etching the copper layer of the flexible circuit copper-clad laminate manufactured through the above process using a known method such as photoetching or the like, thereby obtaining a printed circuit board (PCB).

Hereinafter, pretreatment and film forming conditions (Table 1) for evaluating the properties of the flexible circuit copper clad laminate, evaluation methods of physical properties and experimental examples (Table 2) will be described.

≪ Property evaluation method &

- Peel strength: Peel strength was measured in accordance with IPC-TM-650, NUMBER 2.4.9. UTM equipment is used to average the remaining values except the maximum and minimum values after 8 measurements. The lead width is 1 mm and the required angle is 90 degrees. The film substrate having the lead of 1 mm as an index of heat resistance was left in an oven at 150 캜 for 168 hours, and the peel strength was evaluated.

Oxygen also ryuryang: Prepare a sample 50mm × 50mm, using the Auger analysis equipment obtaining the profile (depth profile) of the depth of the O ₂ content. The analysis is carried out by Auger analysis from the surface of the peeled tie coat layer after measuring the peel strength. The O ₂ content was determined by pre-sputtering O ₂ content in the outermost layer after 5 nm of surface removal to avoid the effect of oxidation on the atmospheric exposure during sample preparation.

- Etching property: A polyimide (PI) / tie coat layer (20 nm) / copper seed layer (60 nm) was deposited and sampled at a size of 30 mm × 30 mm and dipped in an electrochemical test solution to obtain Potentio- , The etching current density value was measured to confirm the etching tendency. (Etching solution conditions: Base 5 ml + DI Water 1.5 L / Base solution: FeCl ₃ .6H ₂ O: 76.2 g + DI water 152.4 g Specific gravity 1.3)

Comparing the experimental results and the experimental results shown in the comparative example 1 with the experimental results shown in the first and third comparative examples, the tie coat layer 2 When the molybdenum content is maintained in the range of 10 wt% to 70 wt%, the properties of the flexible circuit copper-clad laminate are excellent (particularly in terms of etching property and workability).

In particular, the experimental results shown in Example 4 and Comparative Example 4 were compared and the experimental results shown in Example 6 and Comparative Example 6 were compared. As a result, the tie coat layer 2 ) Is maintained in the range of 0.5 wt% to 20 wt%, the properties of the flexible circuit copper-clad laminate are excellent (in particular, in terms of the room-temperature peel strength and the high-temperature peel strength).

That is, in the above content range, the flexible circuit copper-clad laminate maintains a corrosion current density of 0.6 mA / cm ² or more so that no residue is left during etching and the workability is excellent, so that the target is not broken in the sputtering process, And the peel strength at a high temperature are kept at a certain level or more (high temperature: 0.4 kgf / cm or more, room temperature: 0.6 kgf / cm or more), respectively.

Comparing the experimental results and the comparative example as a whole, the experimental results shown in the seventh embodiment and the comparative example 7 are compared in particular. As a result, the oxygen content of the interface region in contact with the polymer film 1 in the tie coat layer 2 Is not more than 2.5 at%, the properties of the flexible circuit copper-clad laminate are excellent (in particular, in terms of high-temperature peel strength).

That is, the high-temperature peel strength of the flexible circuit copper-clad laminate measured in the above range is maintained at 0.4 kgf / cm or more.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not to be limited to the details thereof and that various changes and modifications will be apparent to those skilled in the art. And various modifications and variations are possible within the scope of the appended claims.

1: polymer film 2: tie coat layer
3: copper layer 3a: copper seed layer
3b: Copper coating layer

Claims (17)

A flexible circuit copper clad laminate comprising a polymer film, a tie coat layer formed on at least one side of the polymer film, and a copper (Cu) layer formed on the tie coat layer,
The tie coat layer is composed of an alloy containing 10.0wt% to 70.0wt% molybdenum (Mo), 0.5wt% to 20.0wt% cobalt (Co) and the balance nickel (Ni) alloy Laminates. The method of claim 1,
Wherein an interface region of the tie coat layer in contact with the polymer film has an oxygen content of 2.5at% or less. The method of claim 1,
Wherein the tie coat layer has a corrosion current density of 0.6 mA / cm ² or more. The method of claim 1,
Wherein the thickness of the tie coat layer is 5 nm to 35 nm. The method of claim 1,
Wherein the polymer film is made of at least one of a thermosetting resin, a thermoplastic resin, a polyester resin, a polyimide resin, a condensation polymer, or a mixture of at least two or more thereof. 6. The method of claim 5,
Wherein the polymer film is a polyimide resin. The method of claim 1,
The copper layer may be formed,
A copper seed layer formed on the tie coat layer; And
And a copper coating layer formed on the copper seed layer. 8. The method of claim 7,
Wherein the copper seed layer has a thickness of 20 nm to 100 nm. 9. The method of claim 8,
Wherein the thickness of the copper coating layer is 5 占 퐉 to 15 占 퐉. The printed circuit board provided with the wiring pattern formed in the copper layer of the flexible circuit copper clad laminated board of any one of Claims 1-9. (a) preparing a polymer film;
(b) a tie consisting of an alloy containing molybdenum (Mo), 0.5 wt% to 20.0 wt% of cobalt (Co) and the balance of nickel (Ni) in an amount of 10.0 wt% to 70.0 wt% Forming a coat layer; And
(c) forming a copper layer on the tie coat layer; Method for producing a flexible circuit copper clad laminate comprising a. 12. The method of claim 11,
Wherein the step (a) includes a step of removing the contaminants on the surface and modifying the surface by plasma-treating the polymer film. 12. The method of claim 11,
Wherein the step (b) is a step of depositing a tie coat layer on the polymer film by using a sputtering method. 12. The method of claim 11,
The step (b) is a step of making the interface area in contact with the polymer film of the tie coat layer to have an oxygen content of 2.5 at% or less. 12. The method of claim 11,
Wherein the step (c) is a step of forming a copper seed layer on the tie coat layer and then forming a copper coating layer on the copper seed layer. 16. The method of claim 15,
The copper seed layer is deposited on the tie coat layer by sputtering,
Wherein the copper plating layer is plated on the copper seed layer by an electrolytic plating method. 17. A method for manufacturing a flexible circuit copper clad laminate according to any one of claims 11 to 16; And
And forming a wiring pattern on the copper layer of the flexible circuit copper clad laminate.

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