JP5437228B2 - Copper or copper alloy foil - Google Patents

Description

  The present invention relates to a copper foil or a copper alloy foil having excellent salt corrosion resistance and good solder wettability.

A copper foil or copper alloy foil used for an electric device or an electronic device is used in a state where it is exposed to the outside air even when it is put in a case. Electronic devices that are installed or used outdoors include, for example, mobile phones, digital cameras, and portable navigation systems. These devices are faster than conventional devices due to the lighter, thinner and smaller electronic devices. Downsizing is progressing.
In this case, the more important characteristic than before is the corrosion resistance of the outside air, particularly to corrosive components such as water containing salt. Although there are a plurality of tests for verifying such corrosion resistance, the salt spray test is a typical example. In particular, the corrosion resistance required for copper or copper alloys as metal materials constituting parts that make up electronic devices that are becoming lighter and thinner is becoming more severe every day. In the case of a metal material that does not have corrosion resistance to salt water such as copper or a copper alloy, satisfactory results could not be obtained even if an attempt was made to improve the corrosion resistance performance in place of the alloy.

  In order to solve these problems, in order to suppress or inhibit the corrosion of copper or copper alloys that do not have corrosion resistance against salt water, a treatment that covers and protects the metal surface with organic or inorganic materials is examined. Has been. For example, a surface treatment agent using benzotriazole or epoxysilane is often used. However, in the conventional surface treatment, by treating the metal surface and forming a film, the characteristics of the surface as a metal deteriorated, and as one of the indicators, solder wettability tended to deteriorate.

  Moreover, regarding the fluorine-containing organic compound, an epoxy bleed-out preventing agent containing a fluorine-containing compound having a specific fluorohydrocarbon group and a polar group is known (Patent Document 1). By treating semiconductor base materials such as lead frames and printed wiring boards with the epoxy bleed-out inhibitor, the die bonding strength and assembly characteristics are not adversely affected, and the anti-discoloration treatment and sealing treatment effects are not impaired. Epoxy bleed-out in the bonding process can be prevented. However, this treatment is performed before the circuit process using the epoxy resin, and there is no description regarding the salt water corrosion resistance of the copper foil or the copper alloy foil.

International Publication No. 2007/083538 Pamphlet

  An object of this invention is to implement | achieve the copper foil or copper alloy foil which can keep corrosive by being exposed to the moisture containing salt, and can keep solder wettability favorable.

  In order to solve these problems, as a result of intensive studies, the present inventors have formed a thin film having a thickness of 0.1 to 10 nm containing a specific fluorine-containing compound on a copper foil or a copper alloy foil. Thus, it has been found that the salt water corrosion resistance can be improved without impairing the solder wettability, and the present invention has been completed.

That is, the present invention is as follows.
(1) Copper foil or copper alloy foil, on one or both sides thereof, a fluorohydrocarbon group CxHyFz- (x = 3 to 24, y = 0 to 48, z = 1 to 49, y + z ≦ 2x + 1), Thickness containing a fluorine-containing organic compound having a polar group R- selected from the group consisting of a hydroxyl group, a mercapto group, an amino group, a phosphate ester group, a carboxyl group, an imidazolyl group, a triazolyl group, a tetrazolyl group or a derivative thereof A copper foil or a copper alloy foil comprising a thin film of 1 to 10 nm.
(2) The copper alloy is at least one selected from titanium, tin, nickel, cobalt, silver, lead, zinc, aluminum, beryllium, manganese, iron, zirconium, chromium, phosphorus, silicon, magnesium, arsenic, and tellurium. Two or more elements and copper are contained, The copper foil or copper alloy foil as described in said (1) characterized by the above-mentioned.

  According to the present invention, it is possible to realize a copper foil or a copper alloy foil that can be prevented from being corroded by being exposed to moisture containing salt, and that can maintain good solder wettability.

  The copper foil or copper alloy foil of the present invention comprises a fluorohydrocarbon group CxHyFz- (x = 3 to 24, y = 0 to 48, z = 1 to 49, y + z ≦ 2x + 1), a hydroxyl group, a mercapto group, an amino group, A thin film having a thickness of 0.1 to 10 nm containing a fluorine-containing organic compound having a polar group R- selected from the group consisting of a phosphate ester group, a carboxyl group, an imidazolyl group, a triazolyl group, a tetrazolyl group or a derivative thereof. .

  Examples of the fluorohydrocarbon group include a fluoroalkyl group, a fluoroalkenyl group containing a double bond, a fluoroalkynyl group containing a triple bond, and the like, and a fluoroalkyl group is preferred. Further, these fluorohydrocarbon groups may be linear or have a side chain as long as the total number of carbon atoms in the fluorohydrocarbon group is 3 to 24. Carbon number x of a fluoro hydrocarbon group is 3-24, and the thing of 5-12 is especially preferable. If the carbon number is too small, a sufficient effect for preventing corrosion cannot be obtained. If the carbon number is too large, solder wettability may be deteriorated. On the other hand, if the fluorine number z is small, a sufficient effect for preventing corrosion cannot be obtained. If the number of carbon atoms is large and the molecule is long, the solder wettability deteriorates if the fluorine number is too large. ~ 25 is preferred.

As the fluorohydrocarbon _{group, F (CF 2) 6 -} , F (CF 2) 8 -, F (CF 2) 10 -, F (CF 2) 6 (CH 2) 2 -, F (CF 2) ₈ (CH ₂ ) ₂ —, F (CF ₂ ) ₁₀ (CH ₂ ) ₂ —, and the like can be preferably used.

The polar group R- is selected from the group consisting of a hydroxyl group, a mercapto group, an amino group, a phosphate ester group, a carboxyl group, an imidazolyl group, a triazolyl group, a tetrazolyl group, or a derivative thereof. When the polar group is a phosphate group, a monoester (—OP (O) (OH) ₂ ), a diester ((—O) ₂ P (O) (OH)), a triester ((—O) ₃ P (O)) can be used.

  There are isomers of nitrogen-containing cyclic compounds having an imidazolyl group, triazolyl group, or tetrazolyl group. In the present invention, any of the isomers can be used, and a mixture may be used. For the convenience of synthesis, it is easy to obtain a nitrogen-containing cyclic compound in which nitrogen of the nitrogen-containing cyclic compound is directly bonded to a fluorohydrocarbon group, and it can be preferably used. Examples of the imidazolyl group, triazolyl group, and tetrazolyl group derivative include those having an alkyl group or a phenyl group as a substituent.

Thus, preferred fluorine-containing organic compound, indicating CxHyFz- the fluorohydrocarbon group as A-, for example, A-OH, A-SH , A-NH 2, A-OP (O) (OH) 2, (A-O) ₂ P (O) (OH), (A-O) ₃ P (O), A-COOH, A-N ₂ C ₃ H ₃ (1-imidazolyl), A-N ₃ C ₂ H ₂ (1,2,3-triazol-1-yl), A—N ₄ CH (1-tetrazolyl) and the like.

The copper foil or copper alloy foil of the present invention can be obtained by processing using a processing solution in which the fluorine-containing organic compound as a main component is dissolved in water.
The copper foil and copper alloy foil to be treated may be obtained by a generally known production method, and the copper alloy may be titanium, tin, nickel, cobalt, silver, lead, zinc, aluminum, beryllium, manganese. And an alloy containing copper and at least one element selected from iron, zirconium, chromium, phosphorus, silicon, magnesium, arsenic, and tellurium. The copper alloy preferably has a copper content exceeding 50% by weight.

  The concentration of the fluorine-containing organic compound in the treatment liquid is preferably 10 mg / L to 10 g / L. If the concentration is less than 10 mg / L, the salt corrosion resistance effect is weak, and if it exceeds 10 g / L, the effect is saturated, and further effects cannot be expected.

  When the fluorine-containing organic compound is hardly soluble in water, an organic solvent such as alcohol or ketone can be added as necessary. The amount to be added may be a concentration necessary for the fluorine-containing organic compound to dissolve in water, but is usually preferably 0.1 g / L to 200 g / L, more preferably 1 g / L to 50 g / L. If the amount is less than 0.1 g / L, the effect of improving the solubility of the fluorine-containing organic compound is low, and if the amount exceeds 200 g / L, the effect of dissolving the fluorine-containing organic compound is saturated and no further effect can be expected. It is not preferable.

  Further, when the fluorine-containing organic compound is hardly soluble in water, if necessary, either an anionic, cationic or nonionic surfactant, or a mixture thereof is added at 1 μg / L to 10 g / L, Preferably, 10 μg / L to 1 g / L may be added. If it is less than 1 μg / L, the effect of improving the solubility of the fluorinated organic compound is low, and if it exceeds 10 g / L, the effect of dissolving the fluorinated organic compound is saturated and no further effect can be expected. .

  Further, in the treatment liquid, if it is desired to improve the pH buffering property of the liquid, 0.1 g / L to 200 g / L of a phosphoric acid, boric acid, or organic acid pH buffer is preferably used, May be added in an amount of 1 to 50 g / L. If it is less than 0.1 g / L, the effect of improving the buffering property is low, and if it exceeds 200 g / L, the effect is saturated, and further effects cannot be expected.

  Moreover, when there exists elution of a metal in a process liquid, a metal concealing agent can be used as needed. As this metal concealing agent, basically known ones can be used, but amine-based, aminocarboxylic acid-based and carboxylic acid-based complexing agents are particularly preferable, and 0.1 g / L to 200 g / L, preferably You may add 1g / L-50g / L. If it is less than 0.1 g / L, the complexing power of the metal is low, and if it exceeds 200 g / L, the effect is saturated and no further effect can be expected.

The pH of the treatment liquid is not particularly limited, but is usually between pH 1 and 14, and it is preferable to treat at pH 2-12. If it deviates from this range, it is difficult to form a film having a saltwater corrosion resistance effect, and the material is greatly damaged.
Moreover, although the temperature of a process liquid is possible in the temperature range which can be performed with aqueous solution, it is 5-90 degreeC normally, Preferably you may be 10-60 degreeC. Even if it exceeds 90 ° C., the workability only deteriorates and there is no merit of increasing the temperature.

  Furthermore, the treatment time with the treatment liquid may be appropriately adjusted in view of the effect in 0.1 seconds to 300 seconds, and is preferably 1 second to 60 seconds in consideration of work reproducibility and efficiency. If it is less than 0.1 seconds, it is difficult to form a film having a saltwater corrosion resistance preventing effect, and if it exceeds 300 seconds, the effect is saturated and the working efficiency is lowered.

  In addition, the treatment method can be performed by immersing the copper foil or copper alloy foil in the treatment liquid, or spraying the treatment liquid on the copper foil or copper alloy foil by shower, spraying, or applying by a spin coater or the like. After washing, it may be washed with water and dried.

By performing the above treatment, the fluorine-containing organic compound is adsorbed on one side or both sides of the copper foil or copper alloy foil, and a film containing the fluorine-containing organic compound having a thickness of 0.1 to 10 nm is formed. . If the thickness of the film is less than 0.1 nm, a sufficient effect for preventing corrosion cannot be obtained, and if it exceeds 10 nm, solder wettability deteriorates.
The obtained film has high water repellency, and the surface on which the film is formed has a contact angle with water of 90 degrees or more. Therefore, the saltwater corrosion resistance of the copper foil or copper alloy foil is improved. Moreover, since the film containing the fluorine-containing organic compound is very thin, the solder wettability is not impaired.
The contact angle can be measured by various conventionally known means. In this invention, it measured using the contact angle meter. Specifically, using a contact angle meter CA-DT manufactured by Kyowa Interface Chemical Co., Ltd., measurement was performed at a temperature of 25 ° C. and a liquid volume of about 1.5 μl.
Regarding solder wettability, it can be said that solder wettability is generally good when the zero cross time is 3 seconds or less. In the present invention, that the solder wettability is not impaired means that the solder wettability after the treatment with the corrosion inhibitor is shorter than 3 seconds with a zero cross time and the solder wettability is good. The zero cross time is preferably 2 seconds or less, more preferably 1 second or less, still more preferably 0.3 seconds or less.

  The copper foil and copper alloy foil of the present invention can be used for general applications, respectively, but are particularly suitable for applications that are exposed to the outside air and require corrosion resistance. For example, it can be suitably used for various parts such as a cellular phone, a digital camera, a portable music player, a portable game machine, a netbook portable, a substrate in GPS, a connector, and a contact. Even when the various parts are put in a case, they may be exposed to corrosive outside air such as sea breeze, and corrosion resistance is required.

  EXAMPLES Hereinafter, although this invention is demonstrated based on an Example, this invention is not limited to these Examples.

Examples 1-12, Comparative Examples 1-8
The copper or copper alloy thin film described in Table 1 was subjected to an immersion treatment under the processing conditions described in Table 1 using a processing solution in which the components described in Table 1 were dissolved in water.
The polar groups —N ₂ C ₃ H ₃ , —N ₃ C ₂ H ₂ , and —N ₄ CH of the fluorine-containing organic compounds used in Examples 8, 9, and 10 are a 1-imidazolyl group and 1, 2 , 3-triazol-1-yl group and 1-tetrazolyl group.
Moreover, in Table 1, "-" in a bath composition shows not adding.

About the obtained copper foil or copper alloy foil, salt water corrosion resistance and solder wettability were evaluated as follows.
Salt Water Corrosion Resistance After performing a salt spray test based on JISZ2371, for 72 hours, the weight loss per unit area (corrosion loss) after removing the bulky corrosives with soft paper was determined.
Solder wettability Wetting time (zero cross time) by a solder bath equilibrium method based on JISC0053 was determined. The solder used was Sn-3Ag-0.5Cu lead-free solder, and Tamura Kaken NA-200 was used as the flux.
The results are shown in Table 1.

Claims (2)

  Copper foil or copper alloy foil, on one side or both sides thereof, a fluorohydrocarbon group CxHyFz- (x = 3 to 24, y = 0 to 48, z = 1 to 49, y + z ≦ 2x + 1), hydroxyl group, mercapto A thickness of 0.1 to 0.1% containing a fluorine-containing organic compound having a polar group R- selected from the group consisting of a group, an amino group, a phosphate ester group, a carboxyl group, an imidazolyl group, a triazolyl group and a tetrazolyl group or a derivative thereof A copper foil or copper alloy foil comprising a 10 nm thin film. The copper alloy is at least one selected from titanium, tin, nickel, cobalt, silver, lead, zinc, aluminum, beryllium, manganese, iron, zirconium, chromium, phosphorus, silicon, magnesium, arsenic, and tellurium. The copper foil or copper alloy foil according to claim 1, comprising an element and copper.