KR100646248B1 - The Preparation Method of 2-Layer Copper Clad Laminate - Google Patents

Abstract

The present invention relates to a method for manufacturing a two-layer copper clad laminate (2CCL), and has a functional group that induces adhesion with copper foil instead of polyamic acid (PAA), which has been conventionally used for adhesion in a two-layer copper clad laminate. Coating on copper foil using a monomolecular compound selected from the group consisting of dianhydride compounds and dianhydride compounds, for flexible circuit boards that can significantly increase the adhesion between copper foil and polyimide and reduce the frequency of use of polyamic acid. Provided is a method for producing a two-layer copper clad laminate.

2-layer copper clad laminate (2CCL), polyimide film, flexible circuit board material, imidization

Description

The Preparation Method of 2-Layer Copper Clad Laminate

The present invention relates to a two-layer copper clad laminate (hereinafter referred to as '2CCL'), and more specifically, to a printed circuit board capable of significantly increasing adhesion between copper foil and polyimide, as compared to the prior art. A method for producing a layer copper clad laminate.

The two-layer copper clad laminate is a form of directly bonding copper (Cu) and polyimide (hereinafter referred to as 'PI') films, and compared to so-called 3CCL, in which copper foil and PI film were bonded using a conventional adhesive, It is a flexible circuit board material with excellent durability and electrical characteristics.

There are two methods of making a conventional 2CCL laminate plate, one method is to deposit copper (Cu) on the surface of the PI film formed once (Sputtering method), the other is polyamic acid which is a precursor of PI to copper foil (polyamic acid; hereinafter referred to as 'PAA') A method of forming a laminate by applying a solution (varnish; varnish), drying it, and then curing it (thermally imidization) or chemically (chemical imidization) (Casting method)

Among the various required characteristics of the 2CCL, the adhesive force between the copper foil and the PI is an item that has an important effect on the performance and durability of the circuit board.

Among the two production methods described above, the casting method is most often a case where the adhesive strength is low in applying and curing the polyamic acid to the copper foil. So, until now, the PI which directly touches the copper foil has been applied to the polyamic acid which increases the adhesive strength with the copper foil, and the polyamic acid which affects the overall physical properties is sequentially applied and dried, and then cured to produce a two-layer copper clad laminate. . However, this method can produce a high adhesion 2CCL, but due to the process of applying and drying the polyamic acid with different physical properties two or more times, there is a problem of increasing the hassle and manufacturing cost.

Therefore, in order to solve the above problems, an object of the present invention is to apply a dianhydride or a diamine single molecule to the copper foil that can increase the adhesion, immediately after applying a polyamic acid and cured copper foil and polyimide (PI) It is to provide a method of manufacturing a two-layer copper clad laminate that can increase the adhesive force with and shorten the manufacturing process to bring a cost-effectiveness.

Another object of the present invention is to provide a two-layer copper clad laminate for a flexible printed circuit board manufactured by the above method.

In order to achieve the above object, the present invention                     

a) coating and drying the polyimide precursor solution on copper foil,

b) coating and drying the polyimide precursor solution of said a) on the copper foil obtained by said a),

c) coating, drying and curing the polyimide precursor solution of a) on the copper foil obtained in b), the method of producing a two-layer copper clad laminate,

The solution coated on the copper foil in step a) is a diamine compound represented by the following formula (1), and a dianhydride compound represented by the formula (2) of the two-layer copper clad laminate of one or more selected from the group consisting of It provides a manufacturing method.

[Formula 1]

H ₂ NX ₁ -NH ₂

[Formula 2]

Where

,

,

, 또는 X ₁ is

,

,

, or

이며,

Is,

Wherein Y ₁ and Y ₂ are each independently or simultaneously-, -O-, -CO-, -SO ₂ , -C (CH ₃ ) _2- , -CONH-,-(CH ₂ ) n ₁ -,-( CH ₂ ) n ₂ —O—, —O (CH ₂ ) n ₃ O—, —COO (CH 2) n ₄ OCO—, or a halogen atom, where 1 ≦ n 1, n ₃ , n ₄ ≦ 5, and 0 ≤ n is an integer of ₂ ≤5.

Hereinafter, the present invention will be described in detail.

The present invention is characterized by providing a method for producing a two-layer copper clad laminate (2CCL) using an anhydride or a diamine single molecule that induces adhesion with a copper foil to react with a polyamic acid.

The present invention relates to a two-layer copper clad laminate comprising a) coating of PAA for adhesion, drying step, b) coating of base PAA, drying step, c) coating of PAA, drying step, and d) curing of the entire PAA. In the production method, a diamine-based or dianhydride monomolecular compound capable of enhancing adhesion instead of the polyamic acid used for the adhesion is used, and the subsequent steps proceed in the same manner as in the prior art. According to the present invention, even if the polyamic acid is not used two or more times, sufficient adhesion between the copper foil and the polyimide can be exhibited.

In the method of manufacturing a two-layer copper clad laminate of the present invention, a) applying a solution obtained by dissolving a monomolecular compound inducing adhesion to copper foil in an organic solvent and drying, b) re-coating a polyamic acid dissolved in an organic solvent thereon, Drying, c) coating and drying the polyamic acid solution of step b), and d) curing (imidization) of the polyamic acid.                     

At this time, the monomolecule may react with the polyamic acid. The reacted monomolecule not only induces adhesion with the copper foil but also becomes a polyimide forming a single molecule with the polyamic acid, and thus has high adhesive strength between the copper foil and the polyimide, and thermal stability. Allows you to build 2CCLs.

The monomolecular compound is preferably selected from the group consisting of a diamine compound represented by the following formula (1), and a dianhydride compound represented by the formula (2).

[Formula 1]

H ₂ NX ₁ -NH ₂

[Formula 2]

Where

,

,

, 또는X ₁ is

,

,

, or

이며,

Is,

Wherein Y ₁ and Y ₂ are each independently or simultaneously-, -O-, -CO-, -SO ₂ , -C (CH ₃ ) _2- , -CONH-,-(CH ₂ ) n ₁ -,-( CH ₂ ) n ₂ —O—, —O (CH ₂ ) n ₃ O—, —COO (CH 2) n ₄ OCO—, or a halogen atom, where 1 ≦ n 1, n ₃ , n ₄ ≦ 5, and 0 ≤ n is an integer of ₂ ≤5.

In the process of coating the monomolecular compound on the copper foil, the thickness thereof is preferably 0.01 to 5 μm. Generally, copper foil used in CCL (circuit material) has roughness of about 1 to 3 μm. This is to increase the adhesion to the polyimide by widening the surface area, when the coating thickness is less than 0.01 ㎛ difficult to obtain the effect of increasing the adhesive force. In addition, the polymerization of polyimide regulates the molecular weight of dianhydride or diamine in an equivalence ratio. When the coating thickness exceeds 5 μm, the cast thin film is cast by casting diamine or dianhydride and applying polyamic acid thereon. Since the equivalent ratio of dianhydride and diamine of the whole does not match, it cannot have moderate molecular weight and mechanical properties are not good.

In addition, PAA, the polyimide precursor solution of steps b) and c) is coated with a varnish containing a mixture of dianhydride and diamine in a molar ratio of 1: 0.9 to 1: 1.1 at least once in a solvent. And drying.

The dianhydride is PMDA (pyromellitic dianhydride), BPDA (3,3 ', 4,4'-biphenyltetracarboxylic dianhydride), BTDA (3,3', 4,4). '-Benzophenonetetracarboxylic dianhydride), ODPA (4,4'-oxydiphthalic anhydride), BPADA (4,4'-(4,4'-isopropylbiphenoxy) biphthalic Anhydride), 6FDA (2,2'-bis- (3,4-dicarboxylphenyl) hexafluoropropane dianhydride), TMEG (ethylene glycol bis (anhydro- trimellitate), etc.) It may be one or more selected.

The diamine may be p-PDA (p-phenylenediamine), m-PDA (m-phenylenediamine), 4,4'-ODA (4,4'-oxydianiline), 3,4'- ODA (3,4'-oxydianiline), BAPP (2,2-bis (4- [4-aminophenoxy] -phenyl) propane), TPE-R (1,3-bis (4-aminophenoxy) ) Benzene), m-BAPS (2,2-bis (4- [3-aminophenoxy] phenyl) sulfone) and the like.

Moreover, this invention can also add a small amount of other dianhydrides, another diamine, or another compound other than the said compound as needed.

The solvent is N-methylpyrrolidinone (NMP), N, N-dimethylacetamide (N, N-dimethylacetamide; DMAc), tetrahydrofuran (THF), N, N-dimethylformamide (N, N-dimethylformamide; DMF), dimethylsulfoxide (DMSO), cyclohexane (cyclohexane), acetonitrile (acetonitrile), and mixtures thereof. It doesn't happen.

The coating may be a comma coater, a die coater, or the like, in addition to the other techniques generally used for coating. Drying of the coated varnish depends on the structure and conditions of the oven, but is usually performed at about 100 to 350 ° C, more preferably at about 140 to 250 ° C.                     

As described above, according to the method of the present invention, by using a diamine or a dianhydride monomolecular compound capable of increasing adhesion by reacting with a polyamic acid, a flexible printed circuit board having excellent adhesion between copper foil and polyimide in a simple method as compared with the conventional method. 2-layer copper clad laminated board for this invention can be provided.

The two-layer copper clad laminate of the present invention thus obtained has an adhesive force of at least 500 N / m or more, a moisture absorption of 4% or less, a tensile strength of 13.8 × 10 ⁷ Pa or more, an elongation of 25% or more, and a dielectric constant of 4.0 ^t3 or less.

Hereinafter, the present invention will be described in more detail with reference to Examples. However, the following examples are merely to illustrate the invention and the scope of the present invention is not limited to the following examples.

Example 1

4,4'-oxydianiline of Formula 1a was dissolved in NMP at 10% by weight, and then applied to a copper foil with a thickness of 0.5 μm using a gravure coater. Thereafter, the process of drying polyamic acid polymerized with 20 wt% of PMDA and 4,4-ODA in a molar ratio of 1: 1 was repeated twice. Thereafter, the temperature was raised to 350 ° C at 20 ° C per minute to cure. The thickness of the PI of 2CCL thus prepared was 25 μm and the adhesion between copper foil and PI was 0.9 kg / cm.                     

(Formula 1a)

Example 2

2CCL was prepared in the same manner as in Example 1, but 4,4′-diaminobenzophenone was applied to a thickness of 1 μm. The thickness of the PI of 2CCL thus prepared was 25 μm and the adhesion between copper foil and PI was 1.0 kg / cm.

Example 3

Prepare 2CCL in the same manner as in Example 1, apply TMEG (ethylene glycol bis (anhydro- trimellitate) (Formula 2) to 1㎛ thickness, PMDA and 4,4-ODA 1: 1 The polyamic acid polymerized at 20% by weight in a molar ratio of was applied, dried and cured, and the thickness of PI of 2CCL thus prepared was 25 μm and the adhesion between copper foil and PI was 1.2 kg / cm.

[Formula 2]

Example 4

2,5-bis (4-aminophenyl) -1,3,4-oxadiazole (Formula 1b) was dissolved in NMP at 10 wt% and applied to the electrolytic copper foil using a gravure coater at a thickness of 0.5 um. Polyamic acid obtained by polymerizing BPDA and p-PDA in a 1: 1 weight ratio was applied and dried at 140 ° C. Thereafter, the temperature was raised to 350 ° C at 20 ° C per minute to cure. The thickness of the PI of 2CCL thus prepared was 25 μm and the adhesion between copper foil and PI was 1.0 kg / cm.

Comparative Example 1

In the same manner as in Example 1, but instead of the compound of Formula 1 or 2 in the first copper foil coating process, 20% by weight of polyamic acid polymerized PMDA and 4,4-ODA at a molar ratio of 1: 1 by weight Dried at 140 ° C. Thereafter, the temperature was raised to 350 ° C at 20 ° C per minute to cure. The thickness of the PI of 2CCL thus prepared was 25 μm, and the adhesion between copper foil and PI was 0.5 kg / cm.

Comparative Example 2

In the same manner as in Example 1, in the first copper foil coating process, instead of the compound of Formula 1 or 2, BPDA and p-PDA at a molar ratio of 1: 1 by weight of 20% by weight of polyamic acid 140 Dried at ° C. Thereafter, the temperature was raised to 350 ° C at 20 ° C per minute to cure. The thickness of PI of 2CCL thus prepared was 25 μm and the adhesion between copper foil and PI was 0.4 kg / cm.

Comparative Example 3

In the same manner as in Example 1, the coating thickness of the solution containing a single molecule compound was set to 0.005 ㎛. The thickness of PI of 2CCL thus prepared was 25 μm and the adhesion between copper foil and PI was 0.5 kg / cm.                     

Comparative Example 3

In the same manner as in Example 1, the coating thickness of the solution containing a single molecule compound was 6 ㎛. The PI of the 2CCL prepared in this way was 25 ㎛ and the adhesion between the copper foil and PI was 0.7 kg / cm.

In addition, for Examples 1 to 4, the elongation was tested by a conventional method as mechanical properties.

As a result, in Examples 1 to 4, the elongation rate of the polyimide was about 25%, which satisfies the criterion, but in Comparative Example 3, it was poor, less than 10%.

As described above, the method for producing a two-layer copper clad laminate of the present invention improves the adhesion between the copper foil and the polyimide by using a compound capable of reacting with the polyamic acid, and improves the frequency of use of the polyamic acid used for the adhesion. It is possible to reduce the economic effect.

Claims (7)

a) coating and drying the polyimide precursor solution on copper foil, b) coating and drying the polyimide precursor solution of said a) on the copper foil obtained by said a), c) coating, drying and curing the polyimide precursor solution of a) on the copper foil obtained in b), the method of producing a two-layer copper clad laminate, The solution coated on the copper foil in the step a), at least one selected from the group consisting of a diamine compound represented by the following formula (1), and a dianhydride compound represented by the formula (2) Method for producing a two-layer copper clad laminate comprising: [Formula 1] H ₂ NX ₁ -NH ₂ [Formula 2]

Where X ₁ is

,

,

, or

Is, Wherein Y ₁ and Y ₂ are each independently or simultaneously-, -O-, -CO-, -SO ₂ , -C (CH ₃ ) _2- , -CONH-,-(CH ₂ ) n ₁ -,-( CH ₂ ) n ₂ —O—, —O (CH ₂ ) n ₃ O—, —COO (CH 2) n ₄ OCO—, or a halogen atom, where 1 ≦ n 1, n ₃ , n ₄ ≦ 5, and 0 ≤ n is an integer of ₂ ≤5. The method of claim 1, wherein the coating of the copper foil in step a) is carried out to a thickness of 0.01 to 5 ㎛. The method according to claim 1, wherein the polyimide precursor solution of steps b) and c) is formed in a varnish form in which dianhydride and diamine are mixed in an organic solvent in a molar ratio of 1: 0.9 to 1: 1.1. The dianhydride of claim 3, wherein the dianhydride is pyromellitic dianhydride, 3,3'4,4'-biphenyltetracarboxylic dianhydride, 3,3'.4,4'-benzophenonetetracarboxyl. Rick dianhydride, 4,4'-oxydiphthalic anhydride, 4,4 '-(4,4'-isopropylbiphenoxy) biphthalic anhydride, 2,2'-bis- (3 And 4-dicarboxyphenyl) hexafluoropropane dianhydride, and ethylene glycol bis (anhydro-trimelitate). 4. The diamine according to claim 3, wherein the diamine is p-phenylenediamine, m-phenylenediamine, 4,4'-oxydianiline, 3,4'-oxydianiline, 2,2-bis (4- [4- Aminophenoxy] -phenyl) propane, 1,3-bis (4-aminophenoxy) benzene, and (2,2-bis (4- [3-aminophenoxy] phenyl) sulfone) The manufacturing method will be selected above. The method of claim 1, wherein the solvent is N-methylpyrrolidinone, N, N-dimethylacetamide, tetrahydrofuran, N, N-dimethylformamide, dimethyl sulfoxide, cyclohexane, acetonitrile and mixtures thereof. The production method is selected from the group consisting of. A two-layer copper clad laminate produced by the method of any one of claims 1 to 6.