Surface treatment agent for copper material

Abstract

Provided are: a surface treatment agent capable of forming a film which has excellent insulation properties after heat exposure at high temperatures and which enhances adhesion between a resin material and the surface of a copper material; a surface treatment method for using the surface treatment agent to form the film, which includes a copper oxide on the surface of a copper material; and a copper material having the film. An embodiment of the present invention is a surface treatment agent for a copper material, the surface treatment agent for a copper material including water, copper(II) ions, sulfate ions, and an organic acid, wherein the concentration of the sulfate ions is 1.0-55.0 g / L.

Description

Surface treatment agent for copper materials

[0001] The present invention relates to a surface treatment agent for copper materials.

[0002] There is a need for a method for treating the surface of a copper material to improve its adhesion to a resin. For example, Patent Document 1 discloses a technique for roughening the surface of a wiring including a copper layer using a copper microetching agent made of an aqueous solution containing cupric ions, an organic acid, a halide ion, an amino group-containing compound having a molecular weight of 17 to 400, and a polymer, thereby improving its adhesion to a solder resist or the like.

[0003] JP 2014-25088 A

[0004] Furthermore, in recent years, in order to improve the performance of electronic components containing copper materials, there has been a demand for insulation properties in high-temperature environments, i.e., there is a demand for a technology that can improve the adhesion of resin coatings to copper materials in high-temperature environments.

[0005] Therefore, an object of the present invention is to provide a surface treatment agent that can be applied to electronic components containing copper materials. More specifically, an object of the present invention is to provide a surface treatment agent that can improve adhesion between the surface of a copper material and a resin material and form a coating that exhibits excellent insulating properties after exposure to high temperatures, and a copper material having a coating containing copper oxide obtained using the surface treatment agent.

[0006] The present invention that achieves the above object may include the following.

[0007] One aspect of the present invention is a surface treatment agent for a copper material, which contains water, copper(II) ions, sulfate ions, and an organic acid, and preferably has a sulfate ion concentration of 1.0 g / L or more and 55.0 g / L or less.

[0008] The organic acid preferably includes a water-soluble organic acid having one or two carboxyl groups. The organic acid preferably includes a water-soluble organic acid having one carboxyl group and one hydroxyl group. The copper(II) ion concentration is preferably 0.05 g / L or more and 40.0 g / L or less. When the molar concentrations of the copper(II) ions and the sulfate ions are A and B, respectively, it is preferable that 1.0 < B / A ≦ 10. The pH of the copper material surface treatment agent is preferably 2.0 or more and 6.0 or less. The organic acid preferably includes at least one selected from glycolic acid, lactic acid, and malonic acid. The copper material surface treatment agent preferably includes a water-soluble polymer having an amino group.

[0009] Another aspect of the present invention is a method for treating the surface of a copper material or a method for producing a copper material with a copper oxide-containing film, comprising the step of bringing the surface treatment agent for a copper material into contact with the surface of a copper material to form a copper oxide-containing film.

[0010] Another aspect of the present invention is a method for producing a coated copper material, which includes a step of forming a coating film on the surface of the copper oxide-containing coating.

[0011] Another aspect of the present invention is a copper material with a copper oxide-containing coating obtained by the method for surface treatment of a copper material or the method for producing a copper material with a copper oxide-containing coating, or a copper material with a coating obtained by the method for producing a copper material with a coating.

[0012] According to the present invention, it is possible to provide a surface treatment agent that can improve the adhesion between the surface of a copper material and a resin material and form a coating that has excellent insulating properties after exposure to high temperatures, and a copper material having a coating containing copper oxide that is obtained using the surface treatment agent.

[0013] In this specification, when an upper limit value and a lower limit value are separately described, it is considered that a numerical range combining any upper limit value and any lower limit value is substantially disclosed.

[0014] In this specification, when a compound is described, its isomers are also described.

[0015] In this specification, unless otherwise specified, various measurements are carried out at room temperature (25° C.).

[0016] The present invention will be described in detail below by showing specific embodiments, but the present invention is not limited thereto.

[0017] <Surface Treatment Agent for Copper Material> The surface treatment agent for copper material of this embodiment (hereinafter sometimes simply referred to as surface treatment agent) contains copper (II) ions, sulfate ions, and an organic acid.

[0018] <Copper (II) Ions> The surface treatment agent of this embodiment contains copper (II) ions. The copper (II) ion concentration in the surface treatment agent is not particularly limited, but is preferably 0.05 g / L or more and 25.0 g / L or less, more preferably 0.1 g / L or more and 20.0 g / L or less, and even more preferably 1.0 g / L or more and 15.0 g / L or less. A surface treatment agent having a concentration within this range can form a coating with excellent adhesion between the copper material and the resin material. The concentration of copper (II) ions contained in the surface treatment agent can be measured by oxidation-reduction titration [the method specified in JIS K 8983:2016 (iodometric titration)].

[0019] The copper(II) ion source compound is not particularly limited. A compound that is soluble in water as a solvent and does not inhibit film formation is preferred. Examples of copper(II) ion source compounds include inorganic or organic copper salts such as copper(II) sulfate, copper(II) nitrate, copper(II) formate, copper(II) acetate, copper(II) propionate, copper(II) butyrate, copper(II) lactate, copper(II) malonate, and copper(II) glutarate, as well as hydrates thereof. In this embodiment, two or more of these may be used in combination. Copper(II) sulfate is preferred, with copper(II) sulfate pentahydrate being more preferred. Copper(II) sulfate can also serve as a sulfate ion source, as described below.

[0020] <Sulfate Ions> The compound serving as the sulfate ion source is not particularly limited. The sulfate ion source compound is preferably one that is soluble in water, the solvent, and does not inhibit film formation. Examples of sulfate ion sources include sulfates such as copper sulfate (preferably copper(II) sulfate), sodium sulfate, magnesium sulfate, calcium sulfate, aluminum sulfate, iron sulfate, nickel sulfate, and ammonium sulfate. In this embodiment, two or more selected from these may be used in combination. Using copper(II) sulfate as the sulfate ion source compound also serves as a copper(II) ion source, which allows for a higher proportion of the active ingredient in the solid content of the surface treatment solution according to this embodiment, and is therefore preferred. When copper(II) sulfate is used as the sulfate ion source, the concentrations of sulfate ions and copper(II) ions in the treatment solution may be individually adjusted by further blending a copper(II) ion source or sulfate ion source other than copper(II) sulfate. Specifically, when copper (II) sulfate is used as a compound serving as a sulfate ion source and it is desired to increase the sulfate ion concentration in the treatment solution, it is preferable to further use sodium sulfate as a compound serving as a sulfate ion source.

[0021] The sulfate ion concentration in the surface treatment agent of this embodiment is not particularly limited, but is preferably 1.0 g / L or more, 2.0 g / L or more, 3.0 g / L or more, 5.0 g / L or more, 8.0 g / L or more, or 10.0 g / L or more, and is preferably 55.0 g / L or less, 45.0 g / L or less, 35.0 g / L or less, or 25.0 g / L or less. More specifically, the sulfate ion concentration is preferably 1.0 g / L or more and 55.0 g / L or less, and particularly preferably 3.0 g / L or more and 25.0 g / L or less. By setting the sulfate ion concentration within this range, it is easy to form a coating that has excellent initial insulating properties (insulating properties before exposure to high temperatures) and also excellent insulating properties after exposure to high temperatures.

[0022] When the molar concentrations of copper(II) ions and sulfate ions contained in the surface treatment agent are A and B, respectively, it is preferable that 1.0<B / A<20, and more preferably 1.0<B / A≦10. In other words, B / A is preferably 1.1 or more, 1.2 or more, or 1.4 or more, and is preferably less than 20, 15 or less, or 10 or less. By setting B / A within this range, the functions of copper(II) ions and sulfate ions are well balanced, and it is easy to form a coating that has improved initial insulating properties (insulating properties before exposure to high-temperature heat) and also has excellent insulating properties after exposure to high-temperature heat.

[0023] <Organic Acid> The organic acid preferably has one or two carboxyl groups. The organic acid may or may not have a hydroxyl group.

[0024] The organic acid may be soluble in water. In this embodiment, "soluble in water" or "water-soluble" means that 1 g or more of the organic acid dissolves in 1 L of water at 25°C.

[0025] More specifically, examples of organic acids include formic acid, acetic acid, propionic acid, butyric acid, valeric acid, glycolic acid, lactic acid, hydroxybutyric acid, malonic acid, succinic acid, glutaric acid, and adipic acid. In this embodiment, two or more selected from these may be used in combination. More preferably, the organic acid is at least one selected from glycolic acid, lactic acid, and malonic acid.

[0026] The organic acid in this embodiment may be in the form of an organic salt. Furthermore, in this embodiment, when the surface treatment agent contains an organic acid, this encompasses forms in which the surface treatment agent contains an organic salt, an organic acid ion derived from an organic acid or an organic salt. In this case, the organic salt is preferably one or more selected from the alkali metal salts of the organic acids described above (e.g., lithium salt, sodium salt, potassium salt, etc.). Furthermore, an organic salt of copper(II) (e.g., copper(II) malonate, etc.) is treated as an organic acid and also serves as a copper(II) ion source.

[0027] When the molar concentrations of copper(II) ions and organic acid contained in the surface treatment agent are A and C, respectively, it is preferable that 1.0≦C / A≦10, and more preferably 1.5≦C / A≦4.0. By setting C / A in this range, the stability of the treatment solution can be increased (the occurrence of precipitation can be suppressed), and the etching action and the temperature of the organic acid can be easily optimized, which facilitates the stable formation of a coating. Note that the concentration or molar concentration of the organic acid in the surface treatment agent refers to the concentration or molar concentration in terms of organic acid, which is the sum of the organic acid, organic acid salt, and organic acid ion in the surface treatment agent.

[0028] The concentration of the organic acid contained in the surface treatment agent is not particularly limited, but is preferably 0.5 to 20.0 g / L, more preferably 1.0 to 10.0 g / L, and even more preferably 3.0 to 7.5 g / L.

[0029] <Polymer> The polymer is not particularly limited, but is preferably a water-soluble polymer, and more preferably a water-soluble polymer having an amino group. Examples of water-soluble polymers having an amino group include water-soluble polymers having a heterocyclic amine structure, and more specifically, water-soluble polymers having a constitutional unit represented by the following formula (i):

[0030]

[0031] Examples of polymers having a structural unit represented by the above formula (i) include polydiallylamines such as diallylamine homopolymers, salts of diallylamine homopolymers such as diallylamine methyl sulfate homopolymers, diallylamine sulfate homopolymers, and diallylamine acetate homopolymers, and copolymers having a structural unit represented by the above formula (i) or salts thereof. Examples of copolymers or salts having a structural unit represented by the above formula (i) include those containing a structural unit represented by the above formula (i) and acrylamide, acrylic acid, maleic acid, sulfur dioxide, allylamine, or the like, more specifically, diallylamine sulfate-acrylamide copolymers, diallylamine sulfate-maleic acid copolymers, diallylamine sulfate-sulfur dioxide copolymers, diallylamine acetate-sulfur dioxide copolymers, allylamine sulfate-diallylamine sulfate copolymers, and allylamine acetate-diallylamine acetate copolymers.

[0032] The degree of polymerization of the water-soluble polymer is not particularly limited, but the weight-average molecular weight is preferably in the range of 1,000 to 500,000, more preferably in the range of 3,000 to 150,000, and even more preferably in the range of 5,000 to 100,000. The weight-average molecular weight is a value measured by GPC (gel permeation column chromatography) and converted into polystyrene.

[0033] The content of the polymer (preferably the water-soluble polymer) relative to the total amount of the surface treatment agent is not particularly limited, but is preferably in the range of 1 to 1000 mg / L, more preferably in the range of 3 to 500 mg / L, and even more preferably in the range of 5 to 200 mg / L, in terms of solid mass concentration. A surface treatment agent having a polymer content within the above range can form a film that exhibits excellent adhesion between the copper material and the resin material.

[0034] The water-soluble polymer may be a commercially available product. Examples of commercially available water-soluble polymers include Unisense KCA103LU (diallylamine / acrylamide sulfate copolymer, manufactured by Senka Corporation; active ingredient: 40%), PAA-D19A (allylamine acetate / diallylamine acetate copolymer, manufactured by Nittobo Medical Co., Ltd.; active ingredient: 20%), and PAA-03 (allylamine polymer, manufactured by Nittobo Medical Co., Ltd.; active ingredient: 20%).

[0035] <Other Components> The surface treatment agent for copper materials of this embodiment may or may not contain substances (other components) other than the above-mentioned substances, as long as they do not impair the properties of the surface treatment agent. Examples of other components include halides and compounds containing transition metals other than copper (II). Other examples of other components include pH adjusters, which will be described later.

[0036] <pH of Surface Treatment Agent> The pH of the surface treatment agent in this embodiment is preferably 2.0 or more and 6.0 or less, and more preferably 4.5 or more and 5.5 or less. A surface treatment agent having a pH within this range can form a film with excellent adhesion between the copper material and the resin material. The pH of the surface treatment agent is measured using a pH meter at 25°C.

[0037] The pH of the surface treatment agent can be adjusted using a pH adjuster, such as an acid component such as nitric acid, or an alkali component such as ammonia, lithium hydroxide, or potassium hydroxide. The pH adjuster is not limited to these components. One or more pH adjusters may be used.

[0038] <Method for producing surface treatment agent> The surface treatment agent for copper material of this embodiment is mixed by a known mixing method and mixing device. The order in which the substances contained in the surface treatment agent for copper material of this embodiment are mixed is not particularly limited. In addition, the above substances may be mixed all at once or in portions.

[0039] <Surface Treatment Method> The surface treatment method of the present embodiment is a method including a step of contacting the copper material with the above-described surface treatment agent for copper material.

[0040] <Copper Material> The target of surface treatment with the surface treatment agent of this embodiment is a copper material. The copper material is not particularly limited as long as it contains copper, and examples thereof include pure copper and copper alloys. Examples of pure copper include oxygen-free copper, tough pitch copper, and phosphorus-deoxidized copper. Examples of alloy components other than copper in copper alloys include zinc, phosphorus, aluminum, iron, and nickel. Specific examples of copper alloys include those containing 50% by mass or more of copper (for example, brass containing 30 to 40% by mass of zinc, with the remainder being copper). The shape, structure, etc. of the copper material are not particularly limited. Examples of the shape of the copper material include plate, foil, and rod.

[0041] <Surface Treatment Method> The surface treatment method using the copper material of this embodiment (a method of contacting the surface treatment agent of this embodiment with the surface of the copper material to form a coating) is not particularly limited. Examples include immersion treatment, spray treatment, and pouring treatment. Two or more of these methods can be used in combination. Furthermore, there are no particular limitations on whether the treatment agent is stirred during immersion, the spray pressure during spray treatment, or the type of spray nozzle.

[0042] The temperature at which the copper material is brought into contact with the surface treatment agent is not particularly limited, but is preferably 20°C or higher and 60°C or lower, more preferably 35°C or higher and 45°C or lower.

[0043] The time for contacting the copper material with the surface treatment agent is not particularly limited and can be set appropriately, for example, from 1 second to 15 minutes.

[0044] After contacting the copper material with the surface treatment agent, it is preferable to rinse it with water. The water used can be tap water, industrial water, or well water, but deionized water is optimal. The temperature of the rinsing water is not particularly limited, and it may be heated to speed up drying.

[0045] In the surface treatment method of this embodiment, it is preferable to perform a pretreatment of either or both of a degreasing treatment and a pickling treatment before contacting the copper material with the surface treatment agent. The degreasing solution and the pickling solution are not particularly limited. After the pretreatment, the copper material may be washed with water and then dried, or may not be washed with water and then dried.

[0046] In the surface treatment method of the present embodiment, after the copper material is brought into contact with the surface treatment agent, it may be further post-treated with a rust inhibitor, a post-treatment agent, a pH adjuster, a coupling agent, etc. After the post-treatment, the copper material may be washed with water and then dried, or may be dried without washing with water.

[0047] <Coating> The surface treatment method of this embodiment forms a coating containing copper (I) oxide and / or copper (II) oxide (referred to as a copper oxide coating or a copper oxide-containing coating). In other words, the surface treatment method of this embodiment produces a copper material with a copper oxide coating (a copper material with a copper oxide-containing coating). The ratio of copper (I) oxide to copper (II) oxide in the copper oxide coating is not particularly limited. Furthermore, when the surface treatment solution contains a polymer (particularly, a water-soluble polymer, a water-soluble polymer having an amino group, or a water-soluble polymer having a structural unit represented by formula (i)), a coating containing the polymer (resin coating) is also formed simultaneously with the copper oxide coating. Here, the coating formed by the surface treatment method of this embodiment may be referred to as a surface treatment coating. The surface treatment coating may be either a coating containing a copper oxide coating but not a resin coating, or a coating containing a copper oxide coating and a resin coating.

[0048] The thickness of the copper oxide film formed by the surface treatment agent for copper materials in this embodiment is 1 nm or more and 100 nm or less, preferably 3 nm or more and 70 nm or less, and more preferably 5 nm or more and 50 nm or less. Copper materials with a copper oxide film thickness within this range can exhibit excellent adhesion to resin materials. The thickness of the copper oxide film is calculated by converting the mass of copper oxide calculated by electrochemical reduction method into a thickness.

[0049] The mass of the resin film formed by the surface treatment agent for copper material of this embodiment (for example, a film formed from a water-soluble polymer having a constitutional unit represented by the above formula (i)) is 0.5 mg / m ２ Above, 20mg / m ２ or less, preferably 1 mg / m ２ Above, 15mg / m ２ More preferably, it is 2 mg / m or less. ２ Above, 10mg / m ２Copper materials for which the resin film formed falls within this range can exhibit excellent adhesion to the resin material. The mass of the resin film in the surface treatment film is measured by measuring the carbon adhesion amount using an X-ray fluorescence analyzer and regarding this as the mass of the resin film.

[0050] <Bonding Material> A bonding material exhibiting high adhesion can be obtained by bonding a copper material and a resin material via a surface treatment film formed by surface-treating a copper material using the above-mentioned copper material surface treatment method. The resin material is not particularly limited, and may be a thermoplastic resin or a thermosetting resin. Examples of thermoplastic resins include AS resin, ABS resin, fluororesin, polyamide, polyethylene, polyethylene terephthalate, polyvinylidene chloride, polycarbonate, polystyrene, polysulfone, polypropylene, and liquid crystal polymer. Examples of thermosetting resins include epoxy, phenol, polyimide, polyurethane, bismaleimide-triazine, modified polyphenyl ether, and cyanate ester. These resin materials may be modified with functional groups.

[0051] The method for joining a copper material and a resin material via a surface treatment film is not particularly limited, and any known method can be used. Examples include a method in which a resin material is applied to part or the entire copper material with a surface treatment film formed by contacting the surface of the copper material with the surface treatment agent of the present embodiment, followed by pressure bonding, a method in which the copper material with the surface treatment film is bonded to a resin material by laminating them together using an adhesive or an adhesive sheet, a method in which a bonding material is applied by electrodeposition coating, powder coating, solvent coating, or the like, or a combination of these methods.

[0052] The present invention will be described in detail with reference to the following examples, although the present invention is not limited to these examples.

[0053] <Preparation of Test Panel> A test panel was prepared as follows.

[0054] First, a copper material (150 mm (length) × 70 mm (width) × 0.8 mm (thickness)) was degreased (Fine Cleaner E6400, product name, manufactured by Nippon Parkerizing Co., Ltd., dipping at 60°C for 5 minutes), and then washed with water to clean it.

[0055] Next, a surface treatment agent was prepared by dissolving the components shown in each Example and Comparative Example in Table 1 in water to the corresponding concentration, and the cleaned copper material was immersed in the surface treatment agent to perform the surface treatment. In Table 1, "-" indicates that the corresponding component was not contained. Table 1 also shows the pH of each surface treatment agent. The pH of the surface treatment agent was adjusted with an aqueous sodium hydroxide solution and sulfuric acid. In all examples, the copper material was immersed in the surface treatment agent for a uniform period of 2 minutes, and the temperature was 40°C.

[0056] Next, the surface-treated copper material was used as a substrate and coated using the coating method shown in Table 1 so that the dry film thickness was 20 μm, thereby obtaining test panels for each of the Examples and Comparative Examples.

[0057] The specific conditions for each coating method (electrodeposition coating, powder coating, solvent coating) shown in Table 1 are shown below.

[0058] <Electrodeposition Coating> Test plates were immersed in Electron KG400 (manufactured by Kansai Paint Co., Ltd.), and the voltage was increased to 200 V in 30 seconds, and then maintained for 150 seconds after reaching 200 V, depositing an uncured electrodeposition coating film on the test plate. These test plates were then heated at 180°C for 26 minutes to form an electrodeposition coating film.

[0059] <Powder Coating> Using Innovax P Series (manufactured by Shinto Paint Co., Ltd.), coating was performed using an electrostatic powder coating device manufactured by Parker Engineering Co., Ltd. to apply an uncured powder coating film onto the test plate. The test plate was then heated at 180°C for 20 minutes to form a powder coating film.

[0060] <Solvent Coating> High Merit Primer No. 300 (manufactured by Natoco Corporation) was used. The above paint and Essinner M No. 15 were mixed in a ratio of 100:30 to dilute the paint. A solvent coating film was applied to the test plate by air spraying. The test plate was then heated at 140°C for 20 minutes to form a solvent coating film.

[0061] <Evaluation> The test plates (surface-treated copper materials with coating films) obtained by the above method were subjected to various evaluations as follows. The results are shown in Table 1.

[0062] <Coating Adhesion After High-Temperature Exposure> Each test panel was left to stand in an oven set to 220°C for 625 hours. After 625 hours, the coating adhesion (checkerboard adhesion) was evaluated according to JIS K 5600. Using a cutter knife or the like, 100 squares were cut in a grid pattern that penetrated all the way to the substrate, and cellophane tape was applied to the cut areas. The test was judged based on whether or not the coating peeled off when the cellophane tape was peeled off, and panels that showed no coating peeling were rated as passing.

[0063] <Measurement of Breakdown Voltage> The breakdown voltage (breakdown voltage per unit film thickness) of each test panel was measured using a withstand voltage tester (TOS9201, manufactured by Kikusui Electronics Co., Ltd.) under the conditions of an initial voltage of 0 V, a voltage increase rate of 50 V / sec, and a cutoff current of 1.0 mA.

[0064] <Insulating properties after high-temperature exposure> Each test plate was left standing in an oven set at 220°C for 625 hours. The dielectric breakdown voltage per unit film thickness of the test plate was measured before leaving it in the oven (initial) and after 625 hours of leaving it standing, and the ratio of the value after leaving it standing to the initial value for each test plate was calculated, which was defined as the dielectric breakdown voltage retention rate and compared. A dielectric breakdown voltage retention rate of 85% or more was considered to be acceptable.

[0065]

[0066] The surface treatment agent of the present invention can enhance the adhesion between the surface of a copper material and a resin material and form a film that has excellent insulating properties after exposure to high temperatures. Therefore, the surface treatment agent of the present invention can be applied to the surface treatment of copper materials when producing a bonding material for electronic components in which a copper material and a resin material are bonded together. CROSS-REFERENCE TO RELATED APPLICATIONS

[0067] This application claims priority based on Japanese Patent Application No. 2023-220090, filed with the Japan Patent Office on December 26, 2023, the entire disclosure of which is incorporated herein by reference in its entirety.

Claims

1. A surface treatment agent for copper materials, comprising water, copper (II) ions, sulfate ions, and an organic acid, wherein the concentration of the sulfate ions is 1.0 g / L or more and 55.0 g / L or less.

2. The surface treatment agent for copper materials according to claim 1, wherein the organic acid contains an organic acid having one or two carboxyl groups and being soluble in water.

3. The surface treatment agent for copper materials according to claim 1, wherein the concentration of the copper (II) ions is 0.05 g / L or more and 40.0 g / L or less.

4. The surface treatment agent for copper materials according to claim 1, wherein when the molar concentrations of the copper (II) ions and the sulfate ions are A and B, respectively, 1.0 < B / A ≤ 10.

5. The surface treatment agent for copper materials according to claim 1, wherein the pH is 2.0 or more and 6.0 or less.

6. The surface treatment agent for copper materials according to claim 1, wherein the organic acid contains at least one selected from glycolic acid, lactic acid, and malonic acid.

7. The surface treatment agent for copper materials according to claim 1, comprising a water-soluble polymer having an amino group.

8. A method for manufacturing a copper material with a copper oxide-containing film, comprising the step of bringing the surface treatment agent for copper materials according to any one of claims 1 to 7 into contact with the surface of a copper material to form a copper oxide-containing film.

9. A method for manufacturing a copper material with a coating film, comprising the step of forming a coating film on the surface of the copper oxide-containing film according to claim 8.

10. A copper material with a copper oxide-containing film obtained by the method according to claim 8.

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