KR20160013261A - Pretreatment solution for electroless copper plating, and electroless copper plating method - Google Patents

Abstract

A non-conductive substrate is immersed in a pretreatment liquid for electroless copper plating in which copper nanoparticles having an average particle diameter of 1 to 250 nm are dispersed in a solvent with a dispersant and the contents of the copper nanoparticles and the dispersant are appropriately adjusted to a predetermined range, And the electroless copper plating is performed on the non-conductive substrate. Fine copper nanoparticles having a particle diameter of 250 nm or less are used to prepare a dispersion liquid. Thus, when a non-conductive substrate is immersed and electroless copper plating is performed, a homogeneous copper coating film can be formed on the entire surface of the substrate.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pretreatment liquid for electroless copper plating and an electroless copper plating method for electroless copper plating,

The present invention relates to a pretreatment liquid (electroless copper plating pretreatment liquid) for electroless copper plating and an electroless copper plating method, and more particularly, to an easy-to-handle , It is possible to smoothly conduct electroless copper plating on the surface of the non-conductive substrate.

A resin substrate such as glass / epoxy resin, glass / polyimide resin, epoxy resin, polyimide resin, polycarbonate resin, ABS resin and PET resin is coated on a non-conductive substrate such as a glass substrate or a ceramics substrate, A specific metal such as palladium, silver, platinum, or copper is adsorbed on a substrate to form a catalytic nucleus, and a copper film is formed on the substrate by an electroless copper plating solution through the catalyst nucleus It is necessary to deposit on the substrate.

First, a conventional technique of applying a noble metal such as palladium, silver, or platinum on a substrate by a catalyst and electroless copper plating is described as follows.

(1) Patent Document 1

A primer layer is formed on a non-conductive substrate using a primer composition (primer composition) comprising metal colloid particles obtained by reducing a metal compound in the presence of a polymer pigment dispersant, a curable composition and a solvent, and then electroless plating is performed . The metal colloid particles are preferably silver, palladium, silver / palladium (paragraph 13), and the metal to be electroless plated is nickel or copper (paragraph 147). The curable composition can harden the metal colloid particles on the substrate, and the particles become plating nuclei (plating nuclei), and electroless plating proceeds.

(2) Patent Document 2

Silver alloy and a metal such as palladium, platinum, gold, or tin as an electroless plating catalyst, an alloy nanoparticle layer is formed on the substrate, and electroless copper or nickel plating is performed 4). The alloy nanoparticles are prepared by precipitating hydroxides of the specific metal in the presence of a polymer pigment dispersant and then subjecting to reduction reaction (claim 3).

(3) Patent Document 3

A metal compound (divalent tin, iron, cobalt or trivalent titanium, etc.) having a lower (lower) oxidation-reduction potential than silver, and a carboxylic acid or condensed phosphoric acid (a complexing agent; (nickel or copper plating) on the substrate after applying silver to the non-conductive substrate using a catalyst composition for electroless plating containing a complexing agent (e.g., complexing agent). In the catalyst composition, a silver compound is reduced in a solution containing the complexing agent to form a silver colloid (paragraph 12).

On the other hand, in terms of cost, it is preferable to use inexpensive copper instead of the noble metal as a catalyst nucleus. However, it is not easy to directly impart the catalyst nucleus of metallic copper on a non-conductive substrate. And then electroless copper plating is performed.

(4) Patent Document 4

A solution of a copper compound (copper sulfate or copper nitrate: short circuit 9) was brought into contact with the substrate and dried, and the substrate was immersed in a reducing solution (boron hydride compound, hydrazine, etc., paragraph 12) to form copper fine particles on the substrate , Electroless copper or nickel plating (claims 1 to 4, paragraph 13). The size of the copper microparticles is generally less than 300 nm, most of which is about 100 to 200 nm (paragraph 12).

(5) Patent Document 5

The plating liquid is brought into contact with the liquid containing the tin compound and brought into contact with the liquid containing the copper compound and then a reducing agent such as a hypophosphite salt, an aldehyde salt, an amine borane borane), etc.), the catalyst to be plated is subjected to electroless copper plating (claims 1 to 3).

(6) Patent Document 6

In a direct plating method of copper, a catalyst is added to a non-conductive substrate with a copper-based catalyst containing copper (I) colloid oxide, and then a copper salt, a reducing agent of copper (dimethylamine borane, hydrazine compound, hypophosphite etc.) and Is immersed in a solution containing a complexing agent (polyamine, aminocarboxylic acid, oxycarboxylic acid, etc.) and subjected to reduction reaction or immersion in a solution containing an inorganic acid (for example, sulfuric acid) ), And metal copper is directly deposited on the substrate without electroless copper plating (claims 1 and 2).

Japanese Patent Application Laid-Open No. 2008-007849 Japanese Patent Application Laid-Open No. 2006-225712 Japanese Patent Application Laid-Open No. 2004-190066 Japanese Patent Application Laid-Open No. 6-256961 Japanese Patent Application Laid-Open No. 2002-309376 Japanese Patent Application Laid-Open No. 7-197266

In the above-mentioned prior art for applying copper-based catalyst nuclei on a substrate, Patent Document 4 discloses a method for producing a copper-based catalyst core by attaching a copper salt to a substrate and then applying catalytic nuclei of metallic copper microparticles onto the substrate with a reducing agent, Nickel plating is performed, and the copper salt adhered to the substrate is reduced to be a catalyst nucleus, so that the metal copper is not directly added to the substrate as a catalyst. Also, in Patent Document 6, the copper oxide colloid is applied to the substrate as a catalyst nuclei, and then the substrate is immersed in a solution containing a copper salt, a reducing agent and a complexing agent to form a copper film by a reduction reaction or disproportionation reaction with an inorganic acid As a matter of fact, it is copper oxide which does not provide a metal on the substrate.

On the other hand, for example, even when copper powder having an average particle diameter of μm (for example, several tens of μm) is mixed and stirred in water or an organic solvent, coagulation, precipitation or separation occurs in the mixing system, Even if the resin substrate is immersed in the mixed solution and the electroless copper plating is performed, no copper film is formed. As is apparent from this point, conventionally, it is not easy to directly apply metal copper to a non-conductive substrate such as a resin substrate directly.

Although copper-based catalyst nuclei are provided on the non-conductive substrate in this way, since copper is not directly applied as a catalyst, in the present invention, metal copper is provided as a catalyst by a simple process and electroless copper plating is carried out To be a technical challenge.

The present applicant has disclosed a conductive ink in which copper nanoparticles are dispersed in a solvent by a polymer dispersant in Japanese Patent Laid-Open Publication No. 2011-513934 (referred to as Prior Art 1). In Japanese Patent Application Laid-Open No. 2010-528428 (referred to as Prior Art 2), a film containing a plurality of copper nanoparticles is deposited on a substrate using a solution containing copper nanoparticles, a dispersant, and a solvent, (Exposed), and the exposed portion is made conductive.

As described above, the copper powder used in the technical field of the conductive ink or conductive film described above uses, for example, fine particles having a particle size of less than 1000 nm (see claim 12 of the above-mentioned prior art document 2) It is presumed that the availability of the copper catalyst in the pretreatment of the electroless copper plating (the immersion treatment of the substrate with the mixed solution of the copper powder) largely depends on the stability of the dispersion containing the copper-based compound, To apply this catalyst.

Therefore, although a copper powder finely granulated to a particle diameter of about 500 nm was used, a stable dispersion was not obtained, and since there was no precipitation of a copper film on the resin substrate by electroless plating, the copper powder was finely granulated to a particle size of about 300 nm. Copper powder mixed system was found to exhibit a stable dispersion state and subjected to pretreatment and electroless plating treatment, but copper plating was only partly precipitated unexpectedly.

Therefore, it has been considered that the use of the copper powder finer up to the nano unit makes it difficult to introduce the catalyst of the metal copper onto the resin substrate. However, when the copper nanoparticles are further finely granulated to a particle diameter of 250 nm or less, A uniform copper film can be formed on the substrate by the pretreatment and the electroless plating treatment, and the present invention has been completed.

That is, the present invention 1 is a pretreatment solution for electroless copper plating in which copper particles are dispersed in a solvent with a dispersant in contact with a non-conductive substrate to be subjected to electroless copper plating, wherein the average particle diameter Is 1 to 250 nm, the content of the copper particles in the pretreatment liquid is 1 to 80% by weight, the content of the dispersant in the copper particles is 3 to 70% by weight, the solvent is water Or an organic solvent having a boiling point of 250 DEG C or less and a flash point of 10 DEG C or more at normal pressure, and the pH of the pretreating solution is 3.0 to 10.0.

A second aspect of the present invention is directed to the second aspect of the present invention, wherein the dispersant is at least one selected from the group consisting of an amine, a polyester, a carboxylic acid, a carboxylic acid ester, a phosphoric acid, a phosphoric ester and salts thereof, an alkylol ammonium salt, an alkylammonium salt, Is at least one selected from the group consisting of an ether, a polyether, a polyurethane, a polyacrylate, and a polysiloxane.

A third aspect of the present invention is directed to the first aspect of the present invention, wherein the dispersant is selected from the group consisting of polyoxyethylene dodecyl ether phosphate ester, polyoxyethylene alkyl ether phosphate ester monoethanolamine salt, polyoxyethylene alkylsulfo succinate disodium salt, polyvinylpyrrole Is at least one selected from the group consisting of water, polyethylene glycol, polypropylene glycol, polyvinyl alcohol, quaternary alkylimidazoline, and polyphosphoric acid.

In a fourth aspect of the present invention, in any one of the first to third inventions, the solvent is at least one selected from the group consisting of water, alcohols, glycol ethers, polar alicyclic hydrocarbons (polar alicyclic carbonic hydrogen) , And sulfoxides. The pretreatment liquid for electroless copper plating is at least one selected from the group consisting of:

In the present invention 5, in any one of the above-mentioned inventions 1 to 3, the solvent is selected from the group consisting of isopropyl alcohol, isobutyl alcohol, 3-methoxy-3-methyl-1-butanol, Propylene glycol monomethyl ether, 2-butoxy ethyl acetate, ethylene glycol butyl ether, propylene glycol monomethyl ether acetate, diethylene glycol monoethyl ether acetate, diethylene glycol monoethyl ether acetate, ethylene glycol monomethyl ether acetate, Is at least one selected from the group consisting of 2-ethoxyethyl acetate, ethylene glycol diacetate, N, N-dimethylformamide, dimethyl sulfoxide, N-methyl-2-pyrrolidone and propylene carbonate. It is a pretreatment liquid for copper plating.

A sixth aspect of the present invention is a method for manufacturing a copper plating bath, comprising the steps of: immersing a non-conductive substrate in a pretreatment liquid for electroless copper plating, adsorbing copper particles contained in the pretreatment liquid for electroless copper plating on the surface of the non- And an electroless plating step of forming a copper coating film on the surface of the non-conductive substrate using an electroless copper plating solution, wherein the pretreatment liquid for electroless copper plating is a plating solution for plating, And a pretreatment liquid for electroless copper plating.

When a copper powder of a normal particle size in μm is used, a stable dispersion system of copper particles can not be obtained even when mixed with a solvent. Therefore, even if a non-conductive substrate such as a resin substrate is immersed in the mixing system to deposit an electroless plating solution, Is not formed. Next, copper nanoparticles having a particle size of about 500 nm are used, and copper nanoparticles having a particle size of about 300 nm are dispersed stably in the same manner. On the other hand, copper Since the dispersion liquid is prepared using finer copper nanoparticles having a particle diameter of 250 nm or less in the present invention, if the electroless copper plating is performed after the non-conductive substrate is immersed, a homogeneous and beautiful copper coating is formed on the substrate As shown in Fig.

In the case of copper nanoparticles in nm units, the mechanism (mechanism) thereof is unclear. However, in the case of the particles of 250 nm or less as in the present invention, the anchor effect (anchor effect) I guess it could be expected. Therefore, if the particle diameter is reduced to 250 nm or less, a highly stable dispersion system is formed without causing adverse effects such as aggregation or precipitation, and then the resin substrate is immersed in the dispersion system, whereby metal copper is directly applied to the resin substrate And a copper film can be formed on the substrate well by electroless plating.

1 is a photograph showing the appearance of a copper coating obtained from Example 1A.
2 is a photograph showing the appearance of a copper film obtained from Comparative Example 4A.
3 is a photograph showing the appearance of a copper film obtained from Example 1B.
4 is a photograph showing the appearance of a copper film obtained from Comparative Example 4B.

The present invention relates to a method for electroless copper plating in which adequately finely divided copper nanoparticles (copper particles) for contact with a non-conductive substrate and subjected to pretreatment of electroless copper plating are dispersed in a predetermined solvent by a predetermined dispersing agent (Hereinafter, referred to as a pretreatment liquid). Secondly, a non-conductive substrate is immersed in the pretreatment liquid to give a catalyst of copper, and electroless copper plating is performed on the substrate. The non-conductive substrate refers to a glass substrate, a ceramic substrate, or the like including a resin substrate such as glass / epoxy resin, glass / polyimide resin, epoxy resin, polyimide resin, polycarbonate resin, ABS resin and PET resin.

The pretreatment liquid of the present invention 1 is composed of copper nanoparticles, a dispersing agent and a solvent. The copper nanoparticles of the present invention contained in the pretreatment solution are fine particles having an average particle diameter of 1 to 250 nm, preferably an average particle diameter of 1 to 150 nm, more preferably an average particle diameter of 1 to 120 nm. As described above, the copper nanoparticles having a particle diameter of 250 nm or less are more stable than the copper particles having a larger particle diameter than the copper nanoparticles having a diameter larger than that of the copper nanoparticles in the presence of the dispersing agent in the presence of the dispersing agent, It can be assumed that the anchoring effect promotes the addition of the catalyst nucleus of copper onto the surface of the non-conductive substrate.

On the other hand, if the average particle diameter is larger than 250 nm, coagulation, sedimentation, separation, or the like occurs and a stable dispersion system can not be obtained or an anchor effect can not be expected beyond the stable stable dispersion system. Can not be given, or can only be partially given. Copper nanoparticles satisfying the requirements of the present invention are readily available commercially.

The dispersing agent to be mixed with the pretreatment liquid is to disperse the copper nanoparticles in a disintegrating manner and disperse the dispersed particles stably without aggregation. The dispersing agent is preferably a polymer dispersant having a molecular weight of from 2,000 to 1,000,000, a low molecular dispersant having a molecular weight of less than 2000, Dispersants. The polymer dispersant has a high dispersing action in a small amount and can be expected to have a repulsive effect due to steric hindrance, and can be classified into anionic, cationic, and non-ionic.

Examples of the anion include a polymer dispersant for an organic solvent (for an organic solvent) such as a polycarboxylic acid-based polymer and a naphthalenesulfonic acid-formalin condensation polymer, and a polycarboxylic acid partial alkyl ester-based polymer.

The cationic property includes an organic solvent-based polymeric dispersant such as a polyalkylene polyamine-based polymer.

Examples of non-ionic properties include polymer dispersants for water-based and polyether-based organic solvents such as polyethylene glycol.

The low-molecular dispersant is excellent in the wetting action which is adsorbed on the surface of the copper nanoparticles to make it easy to wet. However, the dispersion stabilizing action is insufficient for the polymer dispersant and can also be classified into anionic, cationic and nonionic.

Anionic low-molecular dispersants such as alkylsulfonic acids and the like are available.

Examples of cationic surfactants include low molecular weight dispersants for organic solvents such as quaternary ammonium salt-based surfactants and alkylpolyamine surfactants.

Examples of the non-ionic property include low molecular weight dispersants for organic solvents such as higher alcohol and alkylene oxide-based water-soluble and polyhydric alcohol ester-based solvents.

The inorganic dispersant is strongly adsorbed on the surface of particles in the aqueous system and stabilized by electrostatic repulsion, and there is an aqueous dispersant such as tripolyphosphate.

Thus, the specific examples of the superordinate concept of the dispersing agent include amines, polyesters, carboxylic acids, carboxylic acid esters, phosphoric acid, phosphoric acid esters and salts thereof, alkylolammonium salts, alkylammonium salts, straight chain alkyl ethers, polyethers, polyurethanes, polyacrylates, polysiloxanes (See invention 2).

In this case, the amine includes an alkylamine, a monoamine, a polyamine and the like, the phosphoric acid includes phosphoric acid and its salt, and the phosphoric acid includes polyphosphoric acid. Specific examples of the intermediate concept include an alkylammonium salt of a block copolymer containing an acid group, an alkylol ammonium salt of a high molecular weight acidic polymer, an alkylol ammonium salt of a polyfunctional polymer, a star-shaped modified polyalkoxylate, Salts of polyaminoamides and acid polymers, polycarboxylates of polyaminoamides, salts of long chain polyaminoamides and polar acid esters, carboxylic acid esters containing hydroxyl groups, alkylol amino amides, unsaturated polycarboxylic acid polyaminoamides, acidic A combination of an alkylammonium salt of a polymer, a modified acrylic block copolymer, a combination of a polar acid ester and a polymer alcohol, an unsaturated polycarboxylic acid polymer, and a combination of an unsaturated acid polycarboxylic acid polyester and a polysiloxane.

Specific examples of the sub-concept of the dispersant include polyoxyethylene dodecyl ether phosphate ester, polyoxyethylene alkyl ether phosphate ester monoethanolamine salt, disodium polyoxyethylene alkylsulfo succinate, polyvinylpyrrolidone, polyethylene glycol, poly Propylene glycol, polyvinyl alcohol, quaternary alkylimidazoline, and polyphosphoric acid (see Invention 3).

Examples of commercially available products of the polymer dispersant include Sol-sperse 3000, Sol Spurs 5000, Sol Spurs 9000, Sol Spurs 12000, Sol Spurs 13240, Sol Spurs 17000, Sol Spurs 20000, Sol Spurs 24000, Sol Spurs 26000, DISPERBYK 101, DISPERBY 102, DISPERBIK 103, DISPERBIC 106, DISPERBY 108, DISPERBY 109, DISPERBY 102, DISPERBY 102, DISPERBY 103, Dispersive 110, Dispersive 111, Dispersive 112, Dispersive 116, Dispersive 130, Dispersive 140, Dispersive 142, Dispersive 145, Dispersive 161, Dispersive 162, Dispersive 163, Dispersive 166, 167, Dispersive 168, Dispersive 170, Dispersive 171, Dispersive 174, Dispersive 180, Dispersive 182, Dispersive 183, Dispersive 184, Dispersive 185, Dispersive 187, Dispersive 190, Dispersive 191 , Dispersive 192, Dispersive 193, Dispersive 194, Dis Dispicbic2001, Dispicbic2008, Dispicbic2009, Dispicic2010, Dispicic2012, Dispicic2022, Dispicic2025, Dispicic2050, Dispicic2070, Dispicic2010, Dispicic2010, Dispicic2010, Dispicic2010, Dispicic2010, Dispicic2010, Dispicic2010, Dispicic2010, Dispicic2010, Dispicic2010, Dispicic2010, Dispicic2010, Dispicic2010, Dispicic2010, Polymer 100, Polymer 120, Polymer 150, Polymer 400, Polymer 100, Polystyrene 20, Dispersive 2091, Dispersive 2095, Dispersive 2096, Dispersive 2150, Dispersive 2155 and ANTI-TERRA- Polymer 401, polymer 402, polymer 403, polymer 450, polymer 451, polymer 452, polymer 453, EFKA-46, EFKA-47, EFKA-48, EFKA-49, EFKA-1501, EFKA-1502, EFKA- -4550 or higher (manufactured by EFKA Chemical), fluorene DOPA-158, fluorene DOPA-22, fluorene DOPA-17, fluorene G-700, fluorene TG-720W, fluorene- , Floren-745W (manufactured by Kyoeisha Chemical Co., Ltd.), Ajisper (AJIS (PER) PA-111, Ajisper PN411, Ajisper PB821, Ajisper PB822, Ajisper PB881 (manufactured by Ajinomoto), DISPARLON 1210, DIPARON 2150, DIPARON KS- Daparron DN-900, Diparron 1880, Diparron 1860, Diparron DA-1401, Diparron PW-36, Diparron DN-900, (Manufactured by Kusumoto Chemical Industry Co., Ltd.), SN-Dis-1, DA-1200, D-Sparone DA-550, Diparron DA-7301, Diparron DA- SN Dispersant 5022, SN Dispersant 5022, SN Dispersant 5022, SN Dispersant 5022, SN Dispersant 5042, SN Dispersant 5040, SN Dispersant 5040, SN Dispersant 5045, SN Dispersant 5468, SN Dispersant 9228, SN Spurs 70, SN Spurs 2190, SN Wet L, SN Wet 366, Knoppers-44-C, Knopp Wet 50, PLYSURF A215C, Flysurf A212C, Flysurf M208F (manufactured by Daiichi Kogyo Seiyaku Co., Ltd.), and the like.

For example, the ANTI-TERRA-250 is an alkylol ammonium salt based dispersant, 180 is a phosphoric acid ester based dispersant, 188 to 185 is a polyurethane based dispersant, 198 to 191, 191, 2015 is a polyacrylate type.

The solvent used for the pretreatment liquid is preferably water or an organic solvent having a boiling point of not higher than 250 ° C and a flash point of not less than 10 ° C at normal pressure from a viewpoint of safety and the like. Specific examples thereof include water, alcohols (including glycols) , Ethers (including glycol ethers), esters (including cyclic esters), polar alicyclic hydrocarbons, amides, sulfoxides and the like. As described above, the dispersion system is very stable by using the copper nanoparticles of the present invention, but from the viewpoint of promoting the stabilization, the solvent of the present invention is preferably a polar solvent, and the oxygen-containing compound or the compound containing an acidic group A polar solvent is more preferable.

Specific examples of the sub-concept of the organic solvent include isopropyl alcohol, isobutyl alcohol, 3-methoxy-3-methyl-1-butanol, 1-octanol, terpineol, cyclohexanol, ethylene glycol, propylene glycol, Propylene glycol monomethyl ether acetate, diethylene glycol monoethyl ether acetate, 2-ethoxy ethyl acetate, ethylene glycol diacetate, N, N-dimethyl Dimethyl sulfoxide, N-methyl-2-pyrrolidone, and propylene carbonate (see Invention 5). Also, methoxypropyl acetate, butyl acetate, dipropylene glycol monomethyl ether, tripropylene glycol monomethyl ether, butyl cellosolve and the like are also effective.

The pretreatment liquid of the present invention is prepared by mixing a dispersant in a solvent and then mixing and stirring the copper nanoparticles, which requires a pH of 3.0 to 10.0 in view of dispersion stability. In the above stirring, it is not necessary to particularly strongly stir or stir. The liquid temperature at the time of mixing and stirring may be room temperature.

The pretreatment solution may contain an antioxidant to prevent surface oxidation of the copper nanoparticles, a pH adjuster comprising various bases such as hydrochloric acid, sulfuric acid, acetic acid, oxalic acid and the like, sodium hydroxide, potassium hydroxide, ammonia water and amine, , Cationic, non-ionic surfactant, and the like.

In the pretreatment liquid of the present invention, the content of copper nanoparticles relative to the total amount of liquid is 1 to 80% by weight, preferably 5 to 70% by weight. If it is less than 1% by weight, it is difficult to adsorb copper nanoparticles uniformly on the substrate. If it exceeds 80% by weight, it is not easy to form a stable dispersion system even if a dispersant is used.

In the pretreatment liquid of the present invention, the content of the dispersing agent in the copper nanoparticles is 3 to 70% by weight, preferably 3 to 50% by weight, though it depends on the kind of the dispersing agent. If it is less than 3% by weight, it is difficult to form a stable dispersion system. If it is more than 70% by weight, impurities may be mixed into the electroless copper film after the catalyst is applied.

A sixth aspect of the present invention is a method for manufacturing a semiconductor device, comprising the steps of: immersing a non-conductive substrate in the pretreatment solution of the first to fifth inventions, and adsorbing the copper nanoparticles contained in the pretreatment liquid on the surface of the non-conductive substrate; And an electroless plating step of forming a copper film on the conductive substrate by using an electroless copper plating solution.

In the pretreatment step, generally, the liquid temperature when the non-conductive substrate is immersed in the pretreatment liquid is 10 to 50 degrees, and the immersion time is 1 to 20 minutes. The non-conductive substrate is as described above including the glass epoxy resin substrate. The non-conductive substrate immersed in the pretreatment liquid is cleaned with pure water and then transferred to an electroless copper plating process without drying or drying.

In the electroless copper plating, it is preferable to perform the same treatment as in the conventional method, and there is no particular limitation. The liquid temperature of the electroless copper plating solution is generally 15 to 70 degrees, preferably 20 to 60 degrees. In the stirring of the copper plating solution, air agitation, rapid liquid flow agitation, mechanical stirring with a stirring blade, or the like can be used.

The composition of the electroless copper plating solution is not particularly limited, and a known copper plating solution can be used. The electroless copper plating solution basically contains a soluble copper salt, a reducing agent and a complexing agent, or may further contain various additives such as a surfactant and a pH adjusting agent or an acid.

As the soluble salt, any salt can be used as long as it is a soluble salt capable of generating the first or second copper ion in an aqueous solution, and there is no particular limitation, and an insoluble salt is not excluded. Specific examples thereof include copper sulfate, copper oxide, copper chloride, copper carbonate, copper acetate, copper pyrophosphate, copper oxalate and the like, and copper sulfate and copper oxide are preferable.

The reducing agent contained in the electroless copper plating solution may be selected from the group consisting of formaldehyde (formalin water), hypophosphorous acids, phosphorous acids, amine borane, hydrogenated boron, glyoxylic acid and the like , And formalin.

The complexing agent contained in the electroless copper plating solution may be at least one selected from the group consisting of ethylenediamine tetraacetic acid (EDTA), diethylenetriamine 5 acetic acid (DTPA), triethylenetetramine 6 acetic acid (TTHA), hydroxyethylethylenediamine 3 acetic acid (HEDTA) Aminocarboxylic acids such as nitrilotriacetic acid (NTA) and iminodiacetic acid (IDA), polyamines such as ethylenediamine, tetramethylenediamine, hexamethylenediamine, diethylenetriamine, tetraethylenepentamine and pentaethylenehexamine, Amino alcohols such as monoethanolamine, diethanolamine and triethanolamine, oxycarboxylic acids such as citric acid, tartaric acid, lactic acid and malic acid, thioglycolic acid, glycine and the like .

As described above, an additive such as a surfactant may be contained in the electroless copper plating solution. In this case, examples of the surfactant include polyethylene glycol, polypropylene glycol, polyoxyethylene-polyoxypropylene random copolymer, polyoxyethylene-poly And an oxypropylene block copolymer. The molecular weight of the polymer is generally in the range of 500 to 1,000,000, preferably 1,000 to 100,000. The pH adjuster is the same as described in the above-mentioned pretreatment liquid.

The electroless copper plating solution may contain an organic acid or an inorganic acid or a salt thereof as a base component of the solution. Examples of the inorganic acid include sulfuric acid, pyrophosphoric acid, and fluoroboric acid. Examples of the organic acid include oxycarboxylic acids such as glycolic acid and tartaric acid, and organic sulfonic acids such as methanesulfonic acid and 2-hydroxyethanesulfonic acid.

[Example]

Hereinafter, examples of the electroless copper plating method of the present invention comprising the preprocessing step and the electroless plating step in which the pretreatment liquid is applied to the resin substrate, the test example of the dispersed state of the preprocessed liquid prepared, the electroless plating on the resin substrate The appearance evaluation test example of the obtained copper coating film will be sequentially described. &Quot;% " It is needless to say that the present invention is not limited to the above-described embodiments and test examples, and can be modified within the scope of the technical idea of the present invention.

In the following examples, the group A is an example using water (water only system or a mixture of water and an organic solvent), and the group B is an example using an organic solvent.

(Example of electroless copper plating method in which the solvent in the pretreatment step is an aqueous solvent)

Example 1A is a basic example of preparing a pretreatment liquid with an aqueous solvent. Examples 2A to 3A are examples in which the particle diameters of the copper nanoparticles of Example 1A are varied, Examples 4A to 6A are examples in which the content of the copper nanoparticles of Example 1A is changed, Example 7A is the example of the dispersion of the dispersant of Example 1A Examples 8A to 14A are examples in which the kind of the dispersant of Example 1A is changed, and Example 20A is an example in which two kinds of dispersants are used.

Examples 1A to 14A and Example 20A are examples in which the solvent is only water, and Examples 15A to 19A are examples in which a mixed solvent of water and an organic solvent is used. On the other hand, Comparative Examples 1A to 4A are examples in which the average particle diameter of the copper powder is larger than the appropriate range of the present invention. Comparative Example 5A is an example in which the content of the copper nanoparticles is less than the appropriate range of the present invention. Comparative Example 6A is an example in which the content of the dispersant is less than the appropriate range of the present invention. Comparative Example 7A is an example in which the content of the dispersant is larger than the appropriate range of the present invention.

(1) Example 1A

After the pretreatment under the following condition (a), electroless copper plating was performed under the condition (b).

(a) Pretreatment process

First, in a glass epoxy copper-clad laminated plate (FR-4 manufactured by Panasonic Electric Works Co., Ltd., thickness of plate: 1.0 mm), a copper foil having a thickness of 35 m was dissolved and removed, .

On the other hand, copper nanoparticles and a dispersant were mixed and stirred in a solvent (pure water) with the following composition to prepare a pretreatment liquid.

[Pretreatment solution]

Copper nanoparticle 5.0g

DISPERBYK-180 1.0 g

pure 5.1 g

DISPERBYK-180 is a dispersing agent of Big Chemical Japan Co., Ltd., and the main component is an alkylammonium salt of a block copolymer including an acid group. In this case, the content of the copper nanoparticles relative to the liquid amount is 45%, and the content of the dispersant with respect to the copper nanoparticles is 20%.

(b) Electroless copper plating process

The electroless copper plating liquid was enriched with the following composition. The pH of the plating solution was adjusted with sodium hydroxide described below.

[Electroless copper plating solution]

Copper sulfate pentahydrate (as Cu2 +) 2.0 g

Formaldehyde 5.0g

EDTA 30.0 g

Sodium hydroxide 9.6 g

Remainder pure

pH (20 degrees) 12.8

The sample substrate was immersed in the pretreatment solution under conditions of 25 degrees and 1 minute, cleaned with pure water, and electroless-plated in the electroless copper plating solution under conditions of 50 degrees and 5 minutes to form a copper film Followed by washing with pure water and drying.

(2) Example 2A

Based on Example 1A, a pretreatment liquid was prepared with the following composition.

Copper nanoparticle 5.0g

DISPERBYK-180 1.0 g

pure 5.1 g

In this case, the copper nanoparticles had a particle diameter of 40 nm.

(3) Example 3A

Based on Example 1A, a pretreatment liquid was prepared with the following composition.

Copper nanoparticle 5.0g

DISPERBYK-180 1.0 g

pure 5.1 g

In this case, the diameter of the copper nanoparticles was 120 nm.

(4) Example 4A

Based on Example 1A, the composition of the pretreatment liquid was changed as follows.

Copper nanoparticle 5.0g

DISPERBYK-180 1.0 g

pure 44.0 g

In this case, the content of the copper nanoparticles relative to the liquid amount is 10%.

(5) Example 5A

Based on Example 1A, the composition of the pretreatment liquid was changed as follows.

Copper nanoparticle 5.0g

DISPERBYK-180 1.0 g

pure 10.7 g

In this case, the content of the copper nanoparticles relative to the liquid amount is 30%.

(6) Example 6A

Based on Example 1A, the composition of the pretreatment liquid was changed as follows.

Copper nanoparticle 5.0g

DISPERBYK-180 1.0 g

pure 2.3 g

In this case, the content of the copper nanoparticles relative to the liquid amount is 60%.

(7) Example 7A

Based on Example 1A, the composition of the pretreatment liquid was changed as follows.

Copper nanoparticle 5.0g

DISPERBYK-180 3.0 g

pure 3.1 g

In this case, the content of the dispersant in the copper nanoparticles is 60%.

(8) Example 8A

Based on Example 1A, the composition of the pretreatment liquid was changed as follows.

Copper nanoparticle 5.0g

ANTI-TERRA-250 1.0 g

pure 5.1 g

In this case, the kind of dispersant was changed from Example 1A. In addition, ANTI-TERRA-250 is a dispersing agent of Big Chem Japan, Inc. and is composed mainly of an alkylol ammonium salt of a high molecular weight acidic polymer.

(9) Example 9A

Based on Example 1A, the composition of the pretreatment liquid was changed as follows.

Copper nanoparticle 5.0g

DISPERBYK-187 1.0 g

pure 5.1 g

In this case, the kind of dispersant was changed from Example 1A. DISPERBYK-187 is a dispersant manufactured by Big Chem Japan Co., Ltd., and is mainly composed of an alkylol ammonium salt solution of a polyfunctional polymer.

(10) Example 10A

Based on Example 1A, the composition of the pretreatment liquid was changed as follows.

Copper nanoparticle 5.0g

DISPERBYK-190 1.0 g

pure 5.1 g

In this case, the kind of dispersant was changed from Example 1A. In addition, DISPERBYK-190 is a dispersing agent of Big Chem Japan Co., Ltd. It is mainly composed of block copolymer of acrylic acid ester.

(11) Example 11A

Based on Example 1A, the composition of the pretreatment liquid was changed as follows.

Copper nanoparticle 5.0g

DISPERBYK-199 1.0 g

pure 5.1 g

In this case, the kind of dispersant was changed from Example 1A. DISPERBYK-199 is a dispersant of Big Chem Japan Co., Ltd., and is mainly composed of a copolymer of acrylic ester.

(12) Example 12A

Based on Example 1A, the composition of the pretreatment liquid was changed as follows.

Copper nanoparticle 5.0g

DISPERBYK-2091 1.0 g

pure 5.1 g

In this case, the kind of dispersant was changed from Example 1A. DISPERBYK-2091 is a dispersant manufactured by Big Chem Japan Co., Ltd., and mainly composed of a modified polyalkoxylate having a modified structure.

(13) Example 13A

Based on Example 1A, the composition of the pretreatment liquid was changed as follows.

Copper nanoparticle 5.0g

FlySurf A215C 1.0 g

pure 5.1 g

In this case, the kind of dispersant was changed from Example 1A. Flysurf A215C is a dispersant of Dai-ichi Kogyo Seiyaku Co., Ltd. and contains polyoxyethylene tridecyl ether phosphate ester as a main component.

(14) Example 14A

Based on Example 1A, the composition of the pretreatment liquid was changed as follows.

Copper nanoparticle 5.0g

FlySurf M208F 1.0 g

pure 5.1 g

In this case, the kind of dispersant was changed from Example 1A. In addition, FlySurf M208F is a dispersing agent produced by Daiichi Kogyo Seiyaku Co., Ltd. and is composed mainly of polyoxyethylene alkyl ether phosphate ester.

(15) Example 15A

Based on Example 1A, the composition of the pretreatment liquid was changed as follows.

Copper nanoparticle 5.0g

DISPERBYK-180 1.0 g

pure 2.6 g

Isopropyl alcohol 2.5 g

In this case, the solvent of Example 1A was changed to a mixed solvent of pure water / alcohol.

(16) Example 16A

Based on Example 1A, the composition of the pretreatment liquid was changed as follows.

Copper nanoparticle 5.0g

DISPERBYK-180 1.0 g

pure 2.6 g

3-methoxy-3-methyl-1-butanol 2.5 g

In this case, the solvent of Example 1A was changed to a mixed solvent of pure water / alcohol.

(17) Example 17A

Based on Example 1A, the composition of the pretreatment liquid was changed as follows.

Copper nanoparticle 5.0g

DISPERBYK-180 1.0 g

pure 2.6 g

Ethylene glycol 2.5 g

In this case, the solvent of Example 1A was changed to a mixed solvent of pure water / alcohol.

(18) Example 18A

Based on Example 1A, the composition of the pretreatment liquid was changed as follows.

Copper nanoparticle 5.0g

DISPERBYK-180 1.0 g

pure 2.6 g

N, N-dimethylformamide 2.5 g

In this case, the solvent of Example 1A was changed to a mixed solvent of a pure water / an organic solvent.

(19) Example 19A

Based on Example 1A, the composition of the pretreatment liquid was changed as follows.

Copper nanoparticle 5.0g

DISPERBYK-180 1.0 g

pure 2.6 g

Dimethyl sulfoxide 2.5 g

In this case, the solvent of Example 1A was changed to a mixed solvent of a pure water / an organic solvent.

(20) Example 20A

Based on Example 1A, the composition of the pretreatment liquid was changed as follows.

Copper nanoparticle 5.0g

DISPERBYK-180 1.0 g

ANTI-TERRA-250 0.3 g

pure 4.8 g

In this case, the dispersant of Example 1A was changed to two mixing systems. Also, ANTI-TERRA-250 has excellent anti-aggregation function.

(21) Comparative Example 1A

Based on Example 1A, a pretreatment liquid was prepared in the following composition.

Copper nanoparticle 5.0g

DISPERBYK-180 1.0 g

pure 5.1 g

However, particles having an average particle diameter of 10 mu m were used as copper powder.

(22) Comparative Example 2A

Based on Example 1A, a pretreatment liquid was prepared in the following composition.

Copper nanoparticle 5.0g

DISPERBYK-180 1.0 g

pure 5.1 g

However, particles having an average particle diameter of 1 mu m were used as copper powder.

(23) Comparative Example 3A

Based on Example 1A, a pretreatment liquid was prepared in the following composition.

Copper nanoparticle 5.0g

DISPERBYK-180 1.0 g

pure 5.1 g

However, copper nanoparticles having an average particle diameter of 500 nm were used.

(24) Comparative Example 4A

Based on Example 1A, a pretreatment liquid was prepared in the following composition.

Copper nanoparticle 5.0g

DISPERBYK-180 1.0 g

pure 5.1 g

However, particles having an average particle diameter of 300 nm were used as the copper nanoparticles.

(25) Comparative Example 5A

Based on Example 1A, the composition of the pretreatment liquid was changed as follows.

Copper nanoparticle 1.0 g

DISPERBYK-180 0.2 g

pure 198.8g

In this case, the content of the copper nanoparticles relative to the liquid amount is 0.5%.

(26) Comparative Example 6A

Based on Example 1A, the composition of the pretreatment liquid was changed as follows.

Copper nanoparticle 5.0g

DISPERBYK-180 0.05 g

pure 6.05 g

In this case, the content of the dispersant in the copper nanoparticles is 1%.

(27) Comparative Example 7A

Based on Example 1A, the composition of the pretreatment liquid was changed as follows.

Copper nanoparticle 5.0g

DISPERBYK-180 3.75g

pure 2.35 g

In this case, the content of the dispersant in the copper nanoparticles is 75%.

(Test example of dispersion state of pretreatment liquid (aqueous system))

First, the dispersion state of the prepared pretreatment liquid was visually observed for Examples 1A to 20A and Comparative Examples 1A to 7A, and the superiority was evaluated based on the following criteria.

?: A stable dispersed phase (dispersed phase) was formed without precipitation or aggregation.

X: Precipitation, aggregation or separation occurred.

(Test for Evaluation of Appearance of Copper Coating on Resin Substrate (aqueous system))

Subsequently, for each of Examples 1A to 20A and Comparative Examples 1A to 7A, the appearance of the copper coating obtained by electroless plating on the pretreated resin substrate was visually observed, and the superiority was evaluated based on the following criteria.

Good: A homogeneous, smooth and beautiful copper film was obtained by electroless plating.

DELTA: Part of the copper film was precipitated.

X: Copper film was not deposited.

However, in Comparative Examples 1A to 2A, since the precipitation and phase separation clearly showed, the pretreatment and the electroless copper plating treatment were not performed.

(Test results of the dispersion state of the pretreatment liquid and the appearance evaluation of the copper coating (aqueous system))

The results of the above tests are shown in Table 1. On the other hand, "-" in Table 1 indicates that pretreatment and electroless plating treatment were not performed.

On the other hand, in the above example, the pretreatment solvent is an aqueous solvent, but in the following, the solvent is an organic solvent.

(Example of the electroless copper plating method in which the solvent in the pretreatment step is an organic solvent)

Example 1B is a basic example of preparing a pretreatment solution with an organic solvent. Examples 2B to 3B are examples in which the particle diameters of the copper nanoparticles of Example 1B are changed, Examples 4B to 6B are examples in which the content of copper nanoparticles in Example 1B is changed, Examples 7B to 8B are Examples in which the content of copper nanoparticles is changed Examples 9B to 15B are examples in which the kind of the dispersant of Example 1B is changed, and Examples 16B to 24B are examples in which the kind of the organic solvent is changed.

On the other hand, Comparative Examples 1B to 4B are examples where the average particle diameter of the copper powder is larger than the appropriate range of the present invention. Comparative Example 5B is an example in which the content of the copper nanoparticles is less than the appropriate range of the present invention. Comparative Example 6B is an example in which the content of the dispersant is less than the appropriate range of the present invention. Comparative Example 7B is an example in which the content of the dispersant is larger than the appropriate range of the present invention.

(1) Example 1B

After the pretreatment under the following condition (a), electroless copper plating was performed under the condition (b).

(a) Pretreatment process

First, a 35-μm copper foil was dissolved and removed in a double-sided copper clad glass / epoxy resin substrate (FR-4 manufactured by Panasonic Electric Works Co., Ltd., thickness of plate: 1.0 mm)

On the other hand, copper nanoparticles and a dispersant were mixed and stirred in a solvent (organic solvent) with the following composition to prepare a pretreatment liquid.

[Pretreatment solution]

Copper nanoparticle 5.0g

DISPERBYK-111 0.2 g

3-methoxy-3-methyl-1-butanol 5.9 g

DISPERBYK-111 is a dispersant manufactured by Big Chem Japan Co., Ltd., and contains a copolymer including an acid group as a main component. The copper nanoparticles have a particle diameter of 80 nm.

In this case, the content of the copper nanoparticles relative to the liquid amount is 45%, and the content of the dispersant with respect to the copper nanoparticles is 4%.

(b) Electroless copper plating process

The electroless copper plating solution was subjected to a bath bath with the following composition. The pH of the plating solution was adjusted with the following sodium hydroxide.

[Electroless copper plating solution]

Copper sulfate pentahydrate (as Cu2 +) 2.0 g

Formaldehyde   5.0g

EDTA 30.0 g

Sodium hydroxide 9.6 g

Remainder pure

pH (20 degrees) 12.8

The sample substrate was immersed in the pretreatment solution under conditions of 25 degrees and 1 minute, cleaned with pure water, and electroless-plated in the electroless copper plating solution under conditions of 50 degrees and 5 minutes to form a copper film Followed by washing with pure water and drying.

(2) Example 2B

Based on Example 1B, a pretreatment liquid was prepared with the following composition.

Copper nanoparticle 5.0g

DISPERBYK-111 0.2 g

3-methoxy-3-methyl-1-butanol 5.9 g

In this case, the copper nanoparticles had a particle diameter of 40 nm.

(3) Example 3B

Based on Example 1B, a pretreatment liquid was prepared with the following composition.

Copper nanoparticle 5.0g

DISPERBYK-111 0.2 g

3-methoxy-3-methyl-1-butanol 5.9 g

In this case, the diameter of the copper nanoparticles was 120 nm.

(4) Example 4B

Based on Example 1B, the composition of the pretreatment liquid was changed as follows.

Copper nanoparticle 5.0g

DISPERBYK-111 0.2 g

3-methoxy-3-methyl-1-butanol 44.8g

In this case, the content of the copper nanoparticles relative to the liquid amount is 10%.

(5) Example 5B

Based on Example 1B, the composition of the pretreatment liquid was changed as follows.

Copper nanoparticle 5.0g

DISP3-ERBYK-111 0.2 g

Methoxy-3-methyl-1-butanol 11.5 g

In this case, the content of the copper nanoparticles relative to the liquid amount is 30%.

(6) Example 6B

Based on Example 1B, the composition of the pretreatment liquid was changed as follows.

Copper nanoparticle 5.0g

DISPERBYK-111 0.2 g

3-methoxy-3-methyl-1-butanol 3.1 g

In this case, the content of the copper nanoparticles relative to the liquid amount is 60%.

(7) Example 7B

Based on Example 1B, the composition of the pretreatment liquid was changed as follows.

Copper nanoparticle 5.0g

DISPERBYK-111 0.5 g

3-methoxy-3-methyl-1-butanol 5.6 g

In this case, the content of the dispersant in the copper nanoparticles is 10%.

(8) Example 8B

Based on Example 1B, the composition of the pretreatment liquid was changed as follows.

Copper nanoparticle 5.0g

DISPERBYK-111 3.0 g

3-methoxy-3-methyl-1-butanol 3.1 g

In this case, the content of the dispersant in the copper nanoparticles is 60%.

(9) Example 9B

Based on Example 1B, the composition of the pretreatment liquid was changed as follows.

Copper nanoparticle 5.0g

FlySurf A212C 0.2 g

3-methoxy-3-methyl-1-butanol 5.9 g

In this case, the kind of dispersant was changed from Example 1B. Flysurf A212C is a dispersant of Daiichi Kogyo Seiyaku Co., Ltd., and is composed mainly of polyoxyethylene tridecyl ether phosphate ester.

(10) Example 10B

Based on Example 1B, the composition of the pretreatment liquid was changed as follows.

Copper nanoparticle 5.0g

DISPERBYK-180 0.2 g

3-methoxy-3-methyl-1-butanol 5.9 g

In this case, the kind of dispersant was changed from Example 1B. DISPERBYK-180 is a dispersant manufactured by BICKEMI Japan Co., Ltd. It mainly contains an alkylammonium salt of a block copolymer containing an acid group.

(11) Example 11B

Based on Example 1B, the composition of the pretreatment liquid was changed as follows.

Copper nanoparticle 5.0g

DISPERBYK-145 0.2 g

3-methoxy-3-methyl-1-butanol 5.9 g

In this case, the kind of dispersant was changed from Example 1B. In addition, DISPERBYK-145 is a dispersing agent manufactured by BICKEMI Japan Co., Ltd., and the phosphoric acid ester salt of the copolymer is the main component.

(12) Example 12B

Based on Example 1B, the composition of the pretreatment liquid was changed as follows.

Copper nanoparticle 5.0g

DISPERBYK-2001 0.2 g

3-methoxy-3-methyl-1-butanol 5.9 g

In this case, the kind of dispersant was changed from Example 1B. DISPERBYK-2001 is a dispersant manufactured by BICKEMI Japan Co., Ltd. It is mainly composed of a modified acrylic block copolymer.

(13) Example 13B

Based on Example 1B, the composition of the pretreatment liquid was changed as follows.

Copper nanoparticle 5.0g

BYK-9076 0.2 g

3-methoxy-3-methyl-1-butanol 5.9 g

In this case, the kind of dispersant was changed from Example 1B. Also, BYK-9076 is a dispersing agent of BICKEMI, Japan, and is mainly composed of an alkylammonium salt of a polymer block of polyamino structure.

(14) Example 14B

Based on Example 1B, the composition of the pretreatment liquid was changed as follows.

Copper nanoparticle 5.0g

BYK-P105 0.2 g

3-methoxy-3-methyl-1-butanol 5.9 g

In this case, the kind of dispersant was changed from Example 1B. Also, BYK-P105 is a dispersing agent manufactured by Big Chem Japan Co., Ltd., and mainly composed of an unsaturated polycarboxylic acid polymer.

(15) Example 15B

Based on Example 1B, the composition of the pretreatment liquid was changed as follows.

Copper nanoparticle 5.0g

ANTI-TERRA-U100 0.2 g

3-methoxy-3-methyl-1-butanol 5.9 g

In this case, the kind of dispersant was changed from Example 1B. In addition, ANTI-TERRA-U100 is a dispersing agent of Big Chem Japan Co., Ltd. It mainly consists of salt of long chain polyaminoamide and acid polymer.

(16) Example 16B

Based on Example 1B, the composition of the pretreatment liquid was changed as follows.

Copper nanoparticle 5.0g

DISPERBYK-111 0.2 g

Isopropyl alcohol 5.9 g

In this case, the kind of organic solvent was changed from Example 1B.

(17) Example 17B

Copper nanoparticle 5.0g

DISPERBYK-111 0.2 g

1-octanol 5.9 g

In this case, the kind of organic solvent was changed from Example 1B.

(18) Example 18B

Based on Example 1B, the composition of the pretreatment liquid was changed as follows.

Copper nanoparticle 5.0g

DISPERBYK-111 0.2 g

Ethylene glycol 5.9 g

In this case, the kind of organic solvent was changed from Example 1B.

(19) Example 19B

Based on Example 1B, the composition of the pretreatment liquid was changed as follows.

Copper nanoparticle 5.0g

DISPERBYK-111 0.2 g

Propylene glycol 5.9 g

In this case, the kind of organic solvent was changed from Example 1B.

(20) Example 20B

Based on Example 1B, the composition of the pretreatment liquid was changed as follows.

Copper nanoparticle 5.0g

DISPERBYK-111 0.2 g

Propylene glycol monomethyl ether 5.9 g

In this case, the kind of organic solvent was changed from Example 1B.

(21) Example 21B

Based on Example 1B, the composition of the pretreatment liquid was changed as follows.

Copper nanoparticle 5.0g

DISPERBYK-111 0.2 g

N, N-dimethylformamide 5.9 g

In this case, the kind of organic solvent was changed from Example 1B.

(22) Example 22B

Based on Example 1B, the composition of the pretreatment liquid was changed as follows.

Copper nanoparticle 5.0g

DISPERBYK-111 0.2 g

Dimethyl sulfoxide 5.9 g

In this case, the kind of organic solvent was changed from Example 1B.

(23) Example 23B

Based on Example 1B, the composition of the pretreatment liquid was changed as follows.

Copper nanoparticle 5.0g

DISPERBYK-111 0.2 g

N-methyl-2-pyrrolidone 5.9 g

In this case, the kind of organic solvent was changed from Example 1B.

(24) Example 24B

Based on Example 1B, the composition of the pretreatment liquid was changed as follows.

Copper nanoparticle 5.0g

DISPERBYK-111 0.2 g

Propylene carbonate 5.9 g

In this case, the kind of organic solvent was changed from Example 1B.

(25) Comparative Example 1B

Based on Example 1B, a pretreatment liquid was prepared in the following composition.

Copper nanoparticle 5.0g

DISPERBYK-111 0.2 g

3-methoxy-3-methyl-1-butanol 5.9 g

However, particles having an average particle diameter of 10 mu m were used as copper powder.

(26) Comparative Example 2B

Based on Example 1B, a pretreatment liquid was prepared in the following composition.

Copper nanoparticle 5.0g

DISPERBYK-111 0.2 g

3-methoxy-3-methyl-1-butanol 5.9 g

However, particles having an average particle diameter of 1 mu m were used as copper powder.

(27) Comparative Example 3B

Based on Example 1B, a pretreatment liquid was prepared in the following composition.

Copper nanoparticle 5.0g

DISPERBYK-111 0.2 g

3-methoxy-3-methyl-1-butanol 5.9 g

However, copper nanoparticles having an average particle diameter of 500 nm were used.

(28) Comparative Example 4B

Based on Example 1B, a pretreatment liquid was prepared in the following composition.

Copper nanoparticle 5.0g

DISPERBYK-111 0.2 g

3-methoxy-3-methyl-1-butanol 5.9 g

However, particles having an average particle diameter of 300 nm were used as the copper nanoparticles.

(29) Comparative Example 5B

Based on Example 1B, the composition of the pretreatment liquid was changed as follows.

Copper nanoparticle 1.0 g

DISPERBYK-111 0.04 g

3-methoxy-3-methyl-1-butanol 198.96g

In this case, the content of the copper nanoparticles relative to the liquid amount is 0.5%.

(30) Comparative Example 6B

Based on Example 1B, the composition of the pretreatment liquid was changed as follows.

Copper nanoparticle 5.0g

DISPERBYK-111 0.05 g

3-methoxy-3-methyl-1-butanol 6.05 g

In this case, the content of the dispersant in the copper nanoparticles is 1%.

(31) Comparative Example 7B

Based on Example 1B, the composition of the pretreatment liquid was changed as follows.

Copper nanoparticle 5.0g

DISPERBYK-111 3.75g

3-methoxy-3-methyl-1-butanol 2.35 g

In this case, the content of the dispersant in the copper nanoparticles is 75%.

(Test Example (Organic Solvent System) of Dispersion State of Pretreatment Solution)

First, the dispersion state of the prepared pretreatment liquid was visually observed for Examples 1B to 24B and Comparative Examples 1B to 7B, and the superiority was evaluated based on the following criteria.

?: A stable dispersed phase was formed without precipitation or agglomeration.

X: Precipitation, aggregation or separation occurred.

(Evaluation test for external appearance of copper film on resin substrate (organic solvent system))

Subsequently, for each of Examples 1B to 24B and Comparative Examples 1B to 7B, the appearance of the copper coating obtained by electroless plating on the pretreated resin substrate was visually observed, and the superiority was evaluated based on the following criteria.

Good: A homogeneous, smooth and beautiful copper film was obtained by electroless plating.

DELTA: Part of the copper film was precipitated.

X: Copper film was not deposited.

However, in Comparative Examples 1B and 2B, there were clear precipitation and phase separation, and therefore, the pretreatment and the electroless copper plating treatment were not performed.

(The dispersion state of the pretreatment liquid and the test results of the appearance evaluation of the copper film (organic solvent system))

The results of the above tests are shown in Table 2. On the other hand, "-" in Table 2 indicates that pretreatment and electroless plating treatment were not performed.

(Comprehensive evaluation of test results)

(1) Examples 1A to 20A and Comparative Examples 1A to 7A using an aqueous solvent for the pretreatment

In Comparative Examples 1A to 2A using copper powders having an average particle size of 10 μm and 1 μm, coagulation and separation were observed at the time when the pretreatment liquid was prepared. As a result, apparent phase separation was confirmed. Thus, pretreatment and electroless copper plating were not performed. Further, in Comparative Example 3A using 500 nm copper nanoparticles, coagulation and separation occurred at the time when the pretreatment liquid was prepared as in Comparative Examples 1A and 2A, and clear phase separation was confirmed. However, since copper particles were refined to less than μm, When electroless copper plating was performed, no copper film was formed.

Next, in Comparative Example 4A in which copper nanoparticles having an average particle size of 300 nm were used, the copper nanoparticles were dispersed in an apparently stable state at the preparation time of the pretreatment liquid. Therefore, when electroless copper plating was carried out, A portion of the substrate not yet precipitated was confirmed on the substrate. Fig. 2 shows the appearance of the copper coating obtained from this Comparative Example 4A.

That is, when the particle diameter of the copper powder is in the unit of μm, a stable dispersed phase can not be obtained even when mixed with a solvent, and even when the particle diameter is 500 nm, the copper powder is not stably dispersed in the same manner. I could confirm. When the particle diameter of the copper powder was reduced to 300 nm, the pretreatment liquid showed a stable dispersion state and the copper film was also precipitated by electroless plating. However, unlike the expectation, it was confirmed that the precipitation did not reach the whole surface but partially precipitated.

On the other hand, in Comparative Example 5A in which the content of the copper nanoparticles was less than the proper range of the present invention, no copper film was precipitated on the resin substrate even when electroless plating was performed. In Comparative Example 7A in which the content of the dispersing agent in the copper nanoparticles exceeded the appropriate range of the present invention, and in Comparative Example 6A in which the content of the dispersant in the copper nanoparticles was less than the appropriate range, there was no precipitation of the copper coating.

On the contrary, in Examples 1A to 20A having particle diameters of 40 to 120 nm in which the content of copper nanoparticles and dispersant was specified within a predetermined range of the present invention and copper nanoparticles were finer than that of Comparative Example 4A, When the solution was prepared, coagulation, sedimentation and phase separation were not observed and a stable dispersion liquid was obtained. On the other hand, unlike Comparative Example 4A, electroless copper plating was performed to form a homogeneous and beautiful copper plating film over the entire surface of the substrate .

Fig. 1 shows the appearance of the copper coating obtained from this Example 1A. In other words, in view of the results of Comparative Example 4A, it was considered that it would not be difficult to apply a catalyst of metal copper over the entire surface of the resin substrate even if copper powders finer to nm units were used. However, when copper nanoparticles were further finely It was confirmed that the homogeneous copper film can be completely deposited on the substrate by pretreatment and electroless plating treatment through stabilization of the dispersion liquid.

Examples 1A to 20A were examined in detail. In the case of Examples 1A to 3A in which the diameters of copper nanoparticles were changed to 40 nm, 80 nm, and 120 nm, electroless plating was performed after the pretreatment, Was obtained on the front. Even if the content of the copper nanoparticles relative to the entire pretreatment liquid was changed (see Example 1A, Examples 4A to 6A), the content of the dispersant in the copper nanoparticles was varied (see Examples 1A and 7A) (See Example 1A and Examples 8A to 14A), or even when the solvent of the pretreatment is pure water or a mixture of pure water and an organic solvent (see Example 1A and Examples 15A to 19A) or using two kinds of dispersants (See Example 1A and Example 20A), there was no difference in that the copper coating formed by electroless plating was homogeneous and beautiful.

(2) Examples 1B to 24B and Comparative Examples 1B to 7B in which an organic solvent was used for the pretreatment

As in the case of the group A of the above-mentioned (1), in Comparative Examples 1B to 3B having an average particle diameter of 10 탆, 1 탆 and 500 nm of the copper powder, a stable dispersion was not obtained and in Comparative Example 4B having an average particle diameter of 300 nm, However, even if the electroless plating was carried out, the copper was not completely precipitated, and the non-precipitated portion was confirmed. Fig. 4 shows the appearance of the copper film of Comparative Example 4B.

Also, in Comparative Examples 5B to 7B in which the contents of the copper nanoparticles and the dispersion were deviated from the requirements of the present invention, there was no precipitation of the copper coating. On the other hand, in Examples 1B to 24B in which all of the particle diameter and the content of the copper nanoparticles and the content of the dispersing agent satisfied the requirements of the present invention, a stable dispersion liquid was obtained and electroless copper plating was carried out to obtain a homogeneous and beautiful copper plating film Can be formed over the entire surface of the substrate. Fig. 3 shows the appearance of the copper coating obtained from Example 1B.

As described above, if the particle diameter and the content of the copper nanoparticles and the content of the dispersant satisfy the requirements of the present invention, metal copper can be easily provided as a catalyst to a non-conductive substrate such as a resin substrate, such as an aqueous solvent or an organic solvent , Whereby it was confirmed that when the pretreated substrate was electroless-plated, a homogeneous and beautiful copper film could be formed well and inexpensively.

In particular, by using water as a solvent, it is possible to apply a catalyst of metal copper to a non-conductive substrate, and electroless copper plating can be performed by a safe and simple operation. In this case, there is no apparent difference in that dispersion of the pretreatment liquid is stabilized in Comparative Example 4B and Examples 1B to 24B as in the case of the Group A of the above-mentioned (1), but in the particle size of 300 nm (Comparative Example 4B) On the other hand, in Examples 1B to 24B in which the grain size was finer than that in Comparative Example 4B, it was possible to achieve total precipitation, and fineness to the optimum grain size of the copper powder had a remarkable effect The point is particularly important.

Claims (6)

(Pretreatment liquid for electroless copper plating) for electroless copper plating in which copper particles are dispersed in a solvent by a dispersing agent in contact with a resin substrate subjected to electroless copper plating,
The average particle diameter of the copper particles is 40 to 120 nm, the content of the copper particles in the pre-treatment solution is 30 to 80% by weight,
The content of the dispersant in the copper particles is 3 to 70% by weight,
Wherein the solvent is water or an organic solvent having a boiling point of 250 DEG C or less and a flash point of 10 DEG C or more at normal pressure,
Wherein the pretreatment liquid has a pH of 3.0 to 10.0.
The method according to claim 1,
Wherein the dispersant is at least one selected from the group consisting of amines, polyesters, carboxylic acids, carboxylic acid esters, phosphoric acid, phosphoric acid esters and salts thereof, alkylolammonium salts, alkylammonium salts, straight chain alkyl ethers, polyethers, polyurethanes, polyacrylates, polysiloxanes Which is a kind of pretreatment liquid for electroless copper plating.
The method according to claim 1,
Wherein the dispersant is selected from the group consisting of polyoxyethylene dodecyl ether phosphate ester, polyoxyethylene alkyl ether phosphate ester monoethanolamine salt, disodium polyoxyethylene alkylsulfo succinate, polyvinyl pyrrolidone, polyethylene glycol, polypropylene glycol, polyvinyl alcohol , Quaternary alkylimidazoline, and polyphosphoric acid. The pretreatment liquid for electroless copper plating according to claim 1,
The method according to any one of claims 1 to 3,
Characterized in that the solvent is at least one selected from the group consisting of water, alcohols, glycol ethers, polar alicyclic hydrocarbons (polar alicyclic charcoal hydrocarbons), amides, sulfoxides and electroless copper plating Pretreatment solution.
The method according to any one of claims 1 to 3,
Wherein the solvent is selected from the group consisting of isopropyl alcohol, isobutyl alcohol, 3-methoxy-3-methyl-1-butanol, 1-octanol, terpineol, cyclohexanol, ethylene glycol, propylene glycol, propylene glycol monomethyl ether, Propylene glycol monomethyl ether acetate, diethylene glycol monoethyl ether acetate, 2-ethoxy ethyl acetate, ethylene glycol diacetate, N, N-dimethylformamide, dimethyl sulfoxide, N-methyl-2-pyrrolidone, and propylene carbonate. The pretreatment liquid for electroless copper plating according to claim 1,
A pretreatment step of immersing a resin substrate in a pretreatment liquid for electroless copper plating and adsorbing copper particles having an average particle diameter of 40 to 120 nm contained in the pretreatment liquid for electroless copper plating on the surface of the resin substrate;
And an electroless plating step of forming a copper film on the surface of the resin substrate subjected to adsorption treatment using an electroless copper plating solution,
Wherein the pretreatment liquid for electroless copper plating is the pretreatment liquid for electroless copper plating according to any one of claims 1 to 3.

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