JP3199208B2 - Organic rust-resistant copper foil and method for producing the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an organic rust-preventive copper foil and a method for producing the same, and more particularly to 3-amino-1,2,4-triazole, silane coupling agent, carboxylic acid or carboxylic acid as an organic rust preventive. By using a mixed solution consisting of a derivative and applying the mixed solution on both sides of the copper foil and then drying, all of the properties of oxidation resistance, peeling strength, hydrochloric acid resistance, moisture resistance and solder wettability are at a high level. And a method for producing the same.

[0002]

2. Description of the Related Art Conventional surface treatment of copper foil is required to ensure peeling strength with a substrate, heat and oxidation resistance, and characteristics required for a circuit board material (hydrochloric acid resistance, moisture resistance, solder wettability, etc.). In order to satisfy these requirements, a very large number of steps such as plating with zinc or an alloy thereof, chromate treatment, and silane coupling agent treatment were required. In addition, management of the plating bath used at that time is required, which is extremely complicated. On the other hand, if these treatments are applied too strongly on the smooth surface of the copper foil, there are also problems such as a problem in solder wettability.

On the other hand, benzotriazole (BTA) and its derivatives have been known and widely used as an organic rust preventive treatment method for copper and copper alloys. Also,
As an example of the use of an organic rust preventive for copper foil, the above-mentioned BTA treatment has been used as a temporary rust preventive treatment for storage.

Recently, carboxybenzotriazole (“Rust Prevention Control”, 1993) has been used as an organic rust inhibitor having heat resistance.
November, p. 417 ") and 3-amino-1,2,4
Various BTA derivatives containing triazole (“Rust Control”, November 1993, p. 412) are being studied.

In these organic rust preventive treatments, a good rust preventive effect can be obtained by a very simple method of applying an aqueous solution containing a rust preventive agent to a copper foil, so that the process for rust preventive is shortened. At the same time, liquid management becomes easy, and its practical use is desired from the viewpoint of process management and cost reduction.

[0006] However, in the field of circuit board materials, which is a main use of copper foil, a heat press is used for bonding to a circuit substrate, so that heat resistance and oxidation resistance at about 180 ° C are required. It is known that the oxidation resistance of conventional BTA rapidly decreases when the temperature exceeds 100 ° C.

Also, BTA such as carboxybenzotriazole and 3-amino-1,2,4-triazole described above.
Derivatives have improved heat and oxidation resistance up to around 200 ° C., but the copper foil treated with these compounds has a lower peel strength with the circuit substrate of 1.0 kg / cm or less.
It is significantly lower than 1.43 kg / cm of the IS standard and is not practical.

Further, when these compounds are treated alone, the solder wettability is very good, probably because of the organic matter, but the hydrochloric acid resistance required as a material of the circuit board,
Most of the properties such as moisture resistance cannot be satisfied.
For example, the hydrochloric acid resistance (evaluated by the deterioration rate of the peeling strength after immersing a 0.8 mm width circuit in a 1: 1 hydrochloric acid solution for 30 minutes) is 40.
%, And the hydrochloric acid resistance of the ordinary treated copper foil described above is 10%.
%, Which is remarkably large as compared with the value of not more than%. Further, the moisture resistance (evaluated by the deterioration rate of the peeling strength after immersing the 0.8 mm width circuit in boiling pure water for 2 hours) is 25%, and the moisture resistance of the ordinary treated copper foil is 10% or less. Significantly larger than

[0009]

SUMMARY OF THE INVENTION The present invention solves the above-mentioned problems of the prior art, maintains the heat-resistant oxidation resistance at about 200 ° C., and has a peel strength with a substrate required as a circuit board material. It is an object of the present invention to provide an organic rust-prevention-treated copper foil satisfying characteristics such as hydrochloric acid resistance, moisture resistance, and solder wettability required as a circuit board material, and a simple and inexpensive manufacturing method thereof.

[0010]

The above object of the present invention is achieved by the following copper foil.

That is, the organic rust-preventive copper foil of the present invention comprises:
An organic rust inhibitor comprising 3-amino-1,2,4-triazole, a silane coupling agent carboxylic acid or a derivative thereof is coated on both surfaces of the copper foil.

The organic rust inhibitor used in the present invention is a mixed solution containing 3-amino-1,2,4-triazole as a main component and a silane coupling agent and a carboxylic acid added thereto. The reason that 3-amino-1,2,4-triazole is used as a main component is to utilize the property that it is not oxidized even when left at 200 ° C. for one hour. The concentration of 3-amino-1,2,4-triazole is 10 mmol / L
-0.5 mol / L is preferable. The concentration is 10 mmol /
If it is less than L, heat resistance and oxidation resistance are not exhibited, and 0.5 mol /
If it exceeds L, the heat and oxidation resistance will not be further improved, and the cost will increase, which is economically disadvantageous.

As silane coupling agents, γ- (methacryloxypropyl) trimethoxysilane, β- (3,
4-epoxycyclohexyl) ethyltrimethoxysilane, γ-glycidoxypropyltrimethoxysilane, N
-Β (aminoethyl) γ-aminopropyldimethoxysilane, N-β (aminoethyl) γ-aminopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, N-phenyl-γ-aminopropyltrimethoxysilane, etc. are used. It is possible. The concentration of the silane coupling agent is preferably from 1 g / L to 10 g / L. When the concentration is less than 1 g / L, not only the heat resistance is reduced, but also the peeling strength and the required characteristics of the circuit board material are reduced. When the concentration exceeds 10 g / L, the required characteristics of the circuit board material are reduced.

As the carboxylic acid or its derivative, dicarboxylic acid, tricarboxylic acid or a derivative thereof can be used. As dicarboxylic acids, maleic acid, fumaric acid,
Succinic acid, malic acid, tartaric acid and the like can be mentioned. As the tricarboxylic acid, citric acid, aconitic acid and the like can be used. Examples of the carboxylic acid derivatives include anhydrides such as maleic anhydride, and metal salt amides, imides, and esters. The concentration of carboxylic acid is 0.1 g / L to 10 g / L
Is preferred. If the concentration is less than 0.1 g / L, not only the heat resistance is reduced, but also the peeling strength and the required characteristics of the circuit board material are reduced. If the concentration is more than 10 g / L, the action as an acid is too strong to dissolve the copper foil. It is not preferable because it will do.

By applying such an organic rust preventive to the surface of the copper foil, the organic rust preventive treated copper foil of the present invention can be obtained. The copper foil used here is not particularly limited, and may be, for example, an electrolytic copper foil or a rolled copper foil.

As a means for applying the organic rust inhibitor to the copper foil, an aqueous solution of an organic rust inhibitor having a predetermined concentration is used, and the copper foil is immersed in the aqueous solution, or the solution is applied by shower (spray) or brush painting. Is applied to the copper foil surface. The coating temperature is preferably from room temperature to 60 ° C. If the temperature exceeds 60 ° C., it is not preferable because polyvinyl chloride cannot be used as equipment, and there are restrictions on facilities, and no improvement in characteristics is observed. The application time may be 1 second or longer, and even if it is 60 seconds or longer, no improvement in characteristics is observed.

The copper foil on which the organic rust inhibitor has been applied is dried without any excess water with a squeezing roll without washing with water. Drying is performed in a drying furnace at 100 to 250 ° C. under ordinary conditions such as 3 to 15 seconds.

[0018]

As described above, 3-amino-1,2,4-triazole alone has a low peeling strength from a circuit substrate and has no practical properties at all as a material for a circuit board. On the other hand, it has been known that a silane coupling agent has an effect of improving the peeling strength between a copper foil and a substrate material, but heat resistance and oxidation resistance can hardly be expected. Further, the carboxylic acid or its derivative alone has only an action of dissolving the copper foil as an organic acid.

According to the study of the present inventors, when 3-amino-1,2,4-triazole is mixed with a silane coupling agent, the heat-resistant oxidation resistance is 3-amino-1,2,4.
-Slightly lower than triazole alone, and the required characteristics as a circuit board material are not improved at all.

Similarly, when 3-amino-1,2,4-triazole is mixed with a carboxylic acid or a derivative thereof, the heat resistance and oxidation resistance do not decrease so much, but all the required characteristics as a circuit board material are not improved.

On the other hand, as in the present invention, 3-amino-
When 1,2,4-triazole, a silane coupling agent, a carboxylic acid or a derivative thereof are mixed at the same time,
Although the detailed mechanism is still unknown, it is possible for the first time to satisfy all of the heat resistance and oxidation resistance, the peel strength with the substrate, and the characteristics required for the circuit board material.

In this case, the heat and oxidation resistance is 200 ° C.
Even after heating for 1 hour, the film does not undergo any oxidative discoloration, the peel strength with the circuit substrate reaches 1.8 kg / cm, which is a practical range, the hydrochloric acid resistance is improved to 15% or less, and the moisture resistance is 10%. It was confirmed to improve to the following.

[0023]

EXAMPLES Hereinafter, the present invention will be specifically described based on examples and the like.

Example 1 An electrolytic copper foil having a thickness of 35 μm was prepared by using 3-amino-1,2,4-
After immersing in an organic rust inhibitor aqueous solution containing 0.1 mol / L of triazole, 5 g / L of γ-glycidoxypropyltrimethoxysilane, and 1 g / L of succinic acid at room temperature for 15 seconds, draining and drying is performed using a drier. Done.

This organic rust-proofed copper foil was reinforced with glass fiber on an epoxy resin plate at a temperature of 170.degree.
The copper-clad laminate was formed by holding at 1 cm ² for 1 hour and pressing.

Next, a circuit was formed so as to leave a copper foil having a width of 0.8 mm, a sample for evaluating characteristics was prepared, and various evaluation tests (peeling strength, hydrochloric acid resistance, moisture resistance, smooth surface solder wettability, Surface heat and oxidation resistance). Table 1 shows the evaluation results.
Shown in

This evaluation method is as described below. Peeling strength: Performed in accordance with JIS C 6481 (however, JIS regulations are measured at a width of 10 mm). Hydrochloric acid resistance: It was immersed in a 1: 1 aqueous hydrochloric acid solution for 30 minutes, and then the peeling strength was measured, and the rate of deterioration from the peeling strength before the test was calculated. Moisture resistance: The peel strength after boiling for 2 hours in boiling distilled water was measured, and the rate of deterioration from the peel strength before the test was calculated. Smooth surface solder wettability: Preflux L-35 (trade name, manufactured by Tamura Corporation) is applied to a copper-clad laminate, dried, dipped in a 260 ° C. solder melt for 3 seconds, and solder is adhered. The evaluation was based on the area ratio. The evaluation criteria are as follows. 〇; 100% △; ≧ 95% ×; <95% Smooth surface heat and oxidation resistance: 200 ° C.
The degree of change in the color tone of the appearance after holding in an oven for 1 hour was compared. The evaluation criteria are as follows. 〇; no change △; slightly discolored ×; reddish brown ×;
Dark purple

Example 2 An electrolytic copper foil having a thickness of 35 μm was coated with 3-amino-1,2,4-
Triazole 0.05 mol / L, N-β (aminoethyl) γ-aminopropyltrimethoxysilane 2 g / L,
After spraying an organic rust inhibitor aqueous solution containing 0.5 g / L of maleic acid at 50 ° C. for 3 seconds, the solution was passed through a drying oven at 150 ° C. for 6 seconds and dried. Hereinafter, evaluation was performed by the same steps as in Example 1, and the results are shown in Table 1.

Example 3 An electrolytic copper foil having a thickness of 35 μm was prepared by using 3-amino-1,2,4-
Triazole 0.4 mol / L, N-phenyl-γ-aminopropyltrimethoxysilane 2 g / L, citric acid 5
After being immersed in an organic rust inhibitor aqueous solution containing g / L for 30 seconds at room temperature, it was dried with a dryer. Hereinafter, evaluation was performed by the same steps as in Example 1, and the results are shown in Table 1.

Comparative Example 1 A 3-amino-1,2,4-
An organic rust inhibitor aqueous solution containing 0.1 mol / L of triazole was sprayed at 50 ° C. for 10 seconds, and then dried with a dryer. Hereinafter, evaluation was performed by the same steps as in Example 1, and the results are shown in Table 1.

COMPARATIVE EXAMPLE 2 An electrolytic copper foil having a thickness of 35 μm was prepared by using 3-amino-1,2,4-
It was immersed in an organic rust inhibitor solution containing 0.1 mol / L of triazole and 5 g / L of γ-glycidoxypropyltrimethoxysilane at room temperature for 15 seconds, and then dried with a dryer. Hereinafter, evaluation was performed by the same steps as in Example 1, and the results are shown in Table 1.

Comparative Example 3 An electrolytic copper foil having a thickness of 35 μm was prepared by using 3-amino-1,2,4-
It was immersed in an organic rust inhibitor solution containing 0.1 mol / L of triazole and 1 g / L of succinic acid at room temperature for 15 seconds, and then dried with a dryer. Hereinafter, evaluation was performed by the same steps as in Example 1, and the results are shown in Table 1.

Comparative Example 4 An electrolytic copper foil having a thickness of 35 μm was immersed in an aqueous organic rust inhibitor containing 5 g / L of γ-glycidoxypropyltrimethoxysilane and 1 g / L of succinic acid at room temperature for 15 seconds. ,
Dryer was dried. Hereinafter, evaluation was performed by the same steps as in Example 1, and the results are shown in Table 1.

Comparative Example 5 A benzotriazole (BT) was applied to an electrolytic copper foil having a thickness of 35 μm.
A) Spraying was performed at 50 ° C. for 10 seconds using an aqueous solution of an organic rust inhibitor containing 0.1 mol / L, followed by drying with a dryer. Hereinafter, evaluation was performed by the same steps as in Example 1, and the results are shown in Table 1.

[0035]

[Table 1]

As is clear from the results in Table 1, Example 1
No. 3 to No. 3 are superior to all of Comparative Examples 1 to 5 in peeling strength, hydrochloric acid resistance, moisture resistance, and heat and oxidation resistance.

[0037]

According to the organic rust-preventive copper foil of the present invention,
By treating the copper foil with an aqueous solution of an organic rust inhibitor containing 3-amino-1,2,4-triazole, a silane coupling agent, a carboxylic acid or a derivative thereof, 200
It is possible to satisfy all of the heat resistance and oxidation resistance at ℃, the peeling strength with the circuit board, and the hydrochloric acid resistance, moisture resistance and solder wettability required for the circuit board material.

Further, the manufacturing method of the present invention shortens the process and facilitates the liquid management, so that the process control is facilitated and the cost can be reduced.

As described above, the organic rust-prevention-treated copper foil of the present invention can be manufactured at lower cost than conventional copper foil, and has almost the same performance as conventional copper foil. The present invention can be suitably substituted for the currently used copper foil and the method for producing the copper foil.

──────────────────────────────────────────────────続 き Continuation of the front page (72) Susumu Takahashi 110-8 Yanaka, Kawagoe-shi, Saitama (56) References JP-A-3-211298 (JP, A) JP-A-3-79781 (JP, A) 58-224178 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) C23F 11/00 H05K 3/38

Claims (2)

(57) [Claims] 1. A method for producing 3-amino-1,2,4 on both surfaces of a copper foil.
An organic rust-preventive copper foil coated with an organic rust-preventive agent comprising a triazole, a silane coupling agent, a carboxylic acid or a derivative thereof; 2. A copper foil having both surfaces of 3-amino-1,2,4
-A method for producing an organic anti-rust treated copper foil, comprising applying an aqueous solution of an organic anti-rust agent comprising a triazole, a silane coupling agent, a carboxylic acid or a derivative thereof, and then drying.