KR20170066886A - Flexible copper clad laminate, printed circuit board using the same - Google Patents

Abstract

A flexible copper clad laminate according to an embodiment of the present invention includes: a resin layer; A tie coat layer formed on the resin layer; And a copper layer formed on the tie coat layer, wherein a binding ratio of CC, CN, CO and C = O appearing on the surface of the tie coat layer at the time of peeling between the resin layer and the tie coat layer ) Is at least 40 at%, at least 25 at%, at least 7 at%, and at least 10 at%.

Description

Technical Field [0001] The present invention relates to a flexible copper clad laminate and a printed circuit board using the same,

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a flexible copper-clad laminate (FCCL) and a printed circuit board using the flexible copper-clad laminate (FCCL), and more particularly to a flexible copper-clad laminate and a printed circuit board using the same.

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, the flexible copper clad laminate (FCCL), which is a raw material for flexible printed circuit boards, is used in digital home appliances such as mobile phones, digital camcorders, notebooks, and LCD monitors. Due to its flexibility, Is rapidly increasing.

The flexible copper-clad laminate is a laminate of a polymer film layer and a metal conductive layer, and is flexible. The flexible copper-clad laminate is used in a part of a material of electronic equipment or electronic equipment which requires flexibility and flexibility, and contributes to miniaturization and weight reduction of electronic equipment.

Conventional flexible 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 copper clad laminate of the deposition type is produced by forming a tie coat layer on a polymer film by a sputtering method and then electrolytically plating copper while continuously passing the tiecoat layer through a copper electrolytic plating bath.

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

Regarding the peel strength of the properties of such a copper-clad laminate, there have been many attempts to improve the high-temperature peel strength characteristics, but the high-temperature peel strength still satisfactory can not be obtained.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems, and it is an object of the present invention to provide a technique capable of remarkably improving high-temperature peeling strength between a resin layer and a tie coat layer.

It is to be understood, however, that the technical scope of the present invention is not limited to the above-mentioned problems, and other technical subjects not mentioned above can be understood by those skilled in the art from the description of the invention described below.

The present inventors have repeatedly studied to develop a technique for improving the high-temperature peeling strength between the resin layer and the tie coat layer. As a result, the inventors of the present invention have found that control is performed such that the CC, CN, CO, and C = O binding ratios appearing on the surface of the metal layer after peeling between the resin layer and the metal layer are at a certain level or more, So as to satisfy the required strength by controlling the illuminance appearing on the surface to be within a certain range to produce a flexible copper-clad laminate.

The flexible copper-clad laminate according to one embodiment of the present invention developed in accordance with the above-described study comprises: a resin layer; A tie coat layer formed on the resin layer; And a copper layer formed on the tie coat layer, wherein a binding ratio of CC, CN, CO and C = O appearing on the surface of the tie coat layer at the time of peeling between the resin layer and the tie coat layer ) Is at least 40 at%, at least 25 at%, at least 7 at%, and at least 10 at%.

In the resin layer, the resin layer may be made of a polyimide (PI) resin.

The resin layer may have a binding ratio of C-C, C-N, C-O, and C = O at the surface thereof of 75 at% or more, 20 at% or more, 5 at% or more, and 10 at% or more.

The tie coat layer may have an illuminance appearing on the surface after peeling from 12 nm to 19 nm.

The tie coat layer may be made of an alloy containing Ni, Mo and Nb.

The tie coat layer may be formed to a thickness of 5 nm to 35 nm.

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 copper seed layer may be formed to a thickness of 10 nm to 100 nm.

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

A printed circuit board according to an embodiment of the present invention includes a wiring pattern formed on a copper layer of a flexible copper clad laminate according to an embodiment of the present invention.

A method of manufacturing a flexible copper clad laminate according to an embodiment of the present invention includes the steps of: (a) preparing a polymer film constituting a resin layer; (b) performing a plasma pretreatment on the resin layer; (c) forming a tie coat layer on the resin layer on which plasma pretreatment has been performed; And (d) forming a copper layer on the tie coat layer; Wherein a binding ratio of CC, CN, CO and C = O at the surface of the resin layer at the time of peeling between the resin layer and the tie coat layer is 40 at% Or more, 25 at% or more, 7 at% or more, and 10 at% or more.

The step (b) may be a step of performing a plasma pretreatment so that the roughness appearing on the surface of the tie coat layer after peeling is 12 nm to 19 nm.

The step (b) may be a step of performing plasma pretreatment so that the roughness appearing on the surface of the tie coat layer after peeling is 12 nm to 19 nm.

The step (b) may be a step of performing a plasma pretreatment under a voltage condition of 2.0 to 2.5 kV using nitrogen gas.

According to an aspect of the present invention, a high-temperature peel strength between a resin layer and a tie coat layer constituting a flexible copper-clad laminate is improved, thereby obtaining a flexible copper-clad laminate having excellent quality.

According to another aspect of the present invention, the quality of the printed circuit board manufactured by forming the wiring pattern on the copper layer of the flexible copper clad laminate by improving the quality of the flexible copper clad laminate can be significantly improved.

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

1 is a sectional view of a flexible copper clad laminate according to an embodiment of the present invention.

Referring to FIG. 1, a flexible copper clad laminate according to an embodiment of the present invention includes a resin layer 1, a tie coat layer 2, and a copper layer 3 sequentially laminated.

The resin layer 1 corresponds to a film made of a polyimide (PI) resin.

In the resin layer (1) used in the present invention, the binding ratios of C-C, C-N, C-O and C═O appearing on the surface are 75at% or more, 20at% or more, 5at% or more and 10at% or more, respectively.

The tie coat layer 2 is formed on the resin layer 1 to improve adhesion between the resin layer 1 and the copper layer 3 and is made of nickel (Ni), molybdenum (Mo), and niobium Nb).

The tie coat layer 2 may be deposited on the resin layer 1 by a sputtering method which is a kind of dry plating method and is preferably formed to a thickness in a range of about 5 nm to 35 nm.

When the thickness of the tie coat layer 2 is less than 5 mm, the resin layer 1 and the tie coat layer 2 are formed in the process of forming the wiring pattern through etching of the flexible copper- There is a fear of deterioration of the peel strength between them.

On the contrary, when the thickness of the tie coat layer 2 exceeds 35 mm, the etching process becomes difficult.

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 about 10 nm to 100 nm.

It is preferable that the copper coating layer 3b is formed on the copper seed layer 3a by electrolytic plating and has a thickness in the range of approximately 5 mu m to 15 mu m.

On the other hand, in the present invention, a plasma pretreatment process for the resin layer (1) is performed prior to the formation of the tie coat layer (2) in order to remove contaminants on the surface of the resin layer (1) and modify the surface.

Such a plasma pretreatment process may be performed using a DC plasma process, an RF plasma process, or an Ion plasma process, and may be performed using a nitrogen (N ₂ ) gas at a voltage range of approximately 2.0 to 2.5 kV.

In this way, the physical properties of the flexible copper-clad laminate can be controlled by limiting the detailed process conditions in the plasma pretreatment process.

Referring to Table 1 below, the results of the high-temperature peel strength test for the flexible copper-clad laminate produced using the resin layer 1 subjected to the plasma pretreatment process are shown.

Preparation of Evaluation Sample

A tie coat layer (NiMoNb) was deposited to a thickness of 20 nm on one surface of a polyimide (PI) substrate used as a substrate, and a copper seed layer was deposited thereon to a thickness of 60 nm. Then, a copper coating layer was formed to a thickness of 12 탆 by electroplating.

When the surface of the PI is subjected to surface modification through plasma treatment before forming the tie coat layer, the resulting soft copper-clad laminate after high-temperature heat treatment has excellent high-temperature peel strength characteristics. Plasma treatment changes the ratio of the functional group of the PI surface, which results in different peel strength between the metal layer and the resin layer.

How to measure property

- Peel Strength: Peel strength was measured in accordance with IPC-TM-650, NUMBER 2.4.9, and after 8 measurements using UTM equipment, the average value of the remaining values except min and min was determined . The film base on which a 1 mm lead was formed as an index of heat resistance was left in an oven at 150 캜 for 168 hours, and the peel strength was evaluated.

- Chemical bonding state (XPS analysis): X-ray was irradiated to measure the kinetic energy of the core electron of the atom to confirm the chemical bonding state of the atom (AXIS-His, KRATOS).

- Surface roughness (AFM analysis): The surface roughness was observed using a micro tip (NANO Stationall. Surface imaging system).

According to the results of the experiment, when the resin layer 1 constituting the flexible copper clad laminate according to the embodiment of the present invention is peeled off from the tie coat layer 2, the surface of the tie coat layer 2 The bonding ratio of CC, CN, CO and C = O in the surface of the flexible copper-clad laminate (the surface which was in contact with the substrate (1)) is more than 40 at%, more than 25 at%, more than 7 at% and 10 at% It can be confirmed that the high-temperature peeling strength is high.

According to the above test results, when the roughness of the surface of the tie coat layer 2 measured after peeling (the surface where the surface of the tie coat layer 2 before the peeling was in contact with the resin layer 1) was in the range of 12 nm to 19 nm, It can be confirmed that the high-temperature peeling strength is sufficiently high.

On the other hand, a desired wiring pattern can be formed by etching the copper layer 2 and the tie coat layer 2 of the flexible copper-clad laminate having the above-mentioned physical properties by a method such as photoetching, So that a printed circuit board (PCB) can be obtained.

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 (14)

Resin layer;
A tie coat layer formed on the resin layer; And
And a copper layer formed on the tie coat layer,
The binding ratios of CC, CN, CO and C = O appearing on the surface of the tie coat layer at the time of peeling between the resin layer and the tie coat layer are 40 at% or more, 25 at% or more, 7 at% or more, 10at% or more. The method according to claim 1,
The resin layer
Wherein the resin layer is made of a polyimide (PI) resin. 3. The method of claim 2,
The resin layer
Wherein the binding ratios of CC, CN, CO and C = O appearing on the surface are 75at% or more, 20at% or more, 5at% or more and 10at% or more, respectively. The method according to claim 1,
The tie coat layer
Wherein the roughness appearing on the surface after peeling is 12 nm to 19 nm. The method according to claim 1,
The tie coat layer
Ni, Mo and Nb. ≪ RTI ID = 0.0 > 11. < / RTI > The method according to claim 1,
The tie coat layer
Wherein the flexible copper clad laminate is formed to a thickness of 5 nm to 35 nm. The method according to 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,
The copper seed layer may include,
Wherein the flexible copper clad laminate has a thickness of 10 nm to 100 nm. 8. The method of claim 7,
The copper coating layer may be formed,
Wherein the flexible copper clad laminate is formed to a thickness of 5 to 15 占 퐉. A printed circuit board comprising a wiring pattern formed on a flexible copper-clad laminate according to any one of claims 1 to 9. (a) preparing a polymer film constituting a resin layer;
(b) performing a plasma pretreatment on the resin layer;
(c) forming a tie coat layer on the resin layer on which plasma pretreatment has been performed; And
(d) forming a copper layer on the tie coat layer; / RTI >
Wherein the binding ratio of CC, CN, CO and C = O at the surface of the resin layer at peeling between the resin layer and the tie coat layer is 40 at% or more and 25 at% or more, Or more, 7 at% or more, and 10 at% or more of the total thickness of the flexible copper clad laminate. 12. The method of claim 11,
The step (b)
And performing plasma pretreatment so that the roughness appearing on the surface of the tie coat layer after peeling becomes 12 nm to 19 nm. 12. The method of claim 11,
The step (b)
And performing plasma pretreatment so that the roughness appearing on the surface of the tie coat layer after peeling becomes 12 nm to 19 nm. 12. The method of claim 11,
The step (b)
And performing a plasma pretreatment under a voltage of 2.0 to 2.5 kV using nitrogen gas.

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