JP6047713B2 - Electroless copper plating method - Google Patents

Description

  The present invention relates to an electroless copper plating method, and when performing electroless copper plating after applying copper nanoparticles having a predetermined particle size or less to a non-conductive substrate by pretreatment, predetermined adsorption promotion is performed before and after the pretreatment. By combining the treatment or the activation treatment in combination, it is possible to increase the deposition rate of the copper film on the substrate and to increase the plating film.

  Electroless copper plating is applied on non-conductive substrates such as glass substrates and ceramic substrates, including glass / epoxy resins, glass / polyimide resins, epoxy resins, polyimide resins, polycarbonate resins, ABS resins, and PET resins. First, a specific metal such as palladium, silver, platinum, or copper is adsorbed on a substrate to make it a catalyst nucleus, and then a copper film is deposited on the substrate by an electroless copper plating solution through the catalyst nucleus. It is necessary to deposit.

Regarding the catalyst application as the pretreatment, there is a conventional technique in which a precious metal such as palladium, silver, or platinum is applied on the substrate, and then electroless copper plating is performed. Preferably, copper is used as the catalyst nucleus.
It is not easy to directly apply a metallic copper catalyst nucleus on a non-conductive substrate such as a resin substrate. For example, after attaching a copper salt to the substrate, a reducing agent provides a catalytic nucleus of metallic copper particles on the substrate. Then, after applying electroless copper plating, or applying copper oxide colloid to the substrate as a catalyst core, by dipping in a solution containing a copper salt, a reducing agent and a complexing agent, or using an inorganic acid Some have formed a copper film by the disproportionation reaction.
However, in these techniques, it is a copper salt such as copper oxide that gives a catalyst to the substrate, not metal copper itself.

  Therefore, the applicant of the present invention previously applied in Japanese Patent Application No. 2011-248664 by a simple process of immersing a non-conductive substrate in a dispersion of copper nanoparticles that have been refined to an average particle size of 250 nm or less. In addition to obtaining knowledge that metal copper can be directly applied with a catalyst, an electroless copper plating method has been proposed that can smoothly form a copper plating film by electroless plating after the application of the catalyst (hereinafter referred to as a prior basic technique).

On the other hand, when electroless copper plating is performed on a substrate provided with a catalyst, there is a method in which electroless copper plating is performed after a predetermined chemical treatment is performed before or after the catalyst is applied.
The prior art is as follows.
(1) Patent Document 1
In performing electroless plating after applying a catalyst to a non-conductive substrate, for the purpose of forming a good electroless plating film having almost no non-plated portion (paragraphs 7 to 8), a palladium compound, a stannous compound, and After contacting the non-conductive substrate with a catalyst-providing solution containing an acid, it is brought into contact with an aqueous solution having a pH of 3 to 11 containing an oxidizing agent such as hydrogen peroxide or percarbonate, or an acidic aqueous solution having a predetermined pH or alkaline in between An electroless plating method is disclosed in which a step of contacting with an aqueous solution is interposed, followed by electroless copper plating (claims 1 to 4, paragraphs 27 to 28).
In Document 1, after the catalyst is applied to the substrate, electroless copper plating is performed after contact with an oxidizing agent-containing liquid or an acidic or alkaline aqueous solution.

(2) Patent Document 2
Resin for the purpose of obtaining an electroless plating film having good appearance and excellent adhesion without using expensive noble metals when performing electroless plating after applying a catalyst to a resin substrate (paragraphs 5 to 7) Etching the substrate, bringing it into contact with a copper compound-containing liquid, bringing it into contact with a liquid containing an oxidizing agent such as sodium peroxodisulfide, hydrogen peroxide, and perchloric acid, bringing it into contact with a liquid containing a nickel compound, and then hydrogen An electroless plating method is disclosed in which a catalyst is provided by contact with a liquid containing a reducing agent such as a boron halide compound, an amine borane, or a hypophosphite, and then an electroless copper plating is performed. (Claims 1 to 4, paragraphs 29, 40, and 45).
In Document 2, the resin substrate is brought into contact with the copper compound-containing liquid and the oxidizing agent-containing liquid in order, and electroless copper plating is performed through other treatments.

(3) Patent Document 3
A method of performing electroless plating after applying a catalyst without using an expensive metal such as palladium (paragraph 9), and (A) a conditioning agent such as an anionic surfactant on an object to be plated such as a resin substrate (Paragraphs 28 and 39), and (B) the surface of the object to be plated by a catalyst treatment using a catalyst solution containing a copper salt and a stannous salt. After forming a copper adsorption layer uniformly (paragraph 31) and (C) performing an activation treatment using amine boranes, borohydride, formaldehyde, etc. to complete the reduction treatment of the adsorbed copper (paragraph 35) An electroless plating method for performing electroless copper plating is disclosed (claims 1-8, paragraph 38).
In the said literature 3, electroless copper plating is performed through the activation process using a reducing agent after the catalyst provision to a resin substrate.

(4) Patent Document 4
A substrate having a non-conductive material portion is subjected to a catalyst treatment, and the catalyst treatment is treated with an alkaline catalyst metal and then treated with a reducing agent solution, or treated with an acidic catalyst metal colloid solution and then treated with an acid solution, It is disclosed that electroless copper plating is performed (claims 1 to 2 and 6).
The catalyst metal is palladium, silver, platinum, gold, nickel, cobalt or the like (paragraph 34), and the reducing agent is a borane compound such as dimethylamine borane or borohydride compound, hydrazine, formaldehyde or the like (paragraph). 41). The treatment with the reducing agent is mainly aimed at the metallization of the applied catalyst, or in some cases, for the purpose of removing the oxide film formed on the metal material, activating the copper portion of the substrate ( Paragraph 38).
The acid solution is a solution of hydrochloric acid, sulfuric acid, etc. (paragraph 33).
Types of electroless plating are copper, tin, silver, nickel, cobalt, etc. (paragraph 42).
In the said literature 4, it processes with a reducing agent or an acid solution after catalyst provision.

(5) Patent Document 5
(I) A surfactant and an acid are brought into contact with the resin molded body, etched, contacted with a colloid solution containing a noble metal compound and a stannous compound, and then (ii) contacted with a liquid containing a palladium compound. It is disclosed that a catalyst is applied and (iii) electroless copper plating is performed (claims 1 to 3).
The surfactant for the etching treatment is various surfactants such as cationic, nonionic, anionic and amphoteric (paragraph 27), and the content thereof is 0.1 to 10 g / L (paragraph 47). Acids include inorganic acids such as sulfuric acid and hydrochloric acid, aliphatic carboxylic acids (such as lauric acid, stearic acid, and oleic acid), oxycarboxylic acids (such as glycolic acid, lactic acid, tartaric acid, malic acid, and citric acid), and aliphatic aminocarboxylic acids (Paragraphs 50 to 51).
In the said literature 5, the resin molding is processed with surfactant or an acid before catalyst provision.

(6) Patent Document 6
For the purpose of steadily activating the copper portion of the object to be plated and depositing the electroless copper plating film uniformly (paragraphs 8-9), the activity containing a reducing agent and a surfactant and adjusted to pH 1-7 It is disclosed that electroless copper plating is performed after immersing an object to be plated in a crystallization solution (Claim 5).
As the reducing agent, formalin is suitable (paragraph 12), and as the surfactant, nonionic surfactants, particularly polyethylene glycol are suitable (paragraph 14).
In the document 6, a reducing agent and a surfactant are used for the activation process before electroless plating.

JP 2001-323383 A Japanese Patent Laid-Open No. 2003-041375 JP 2008-214706 A JP-A-2005-008936 JP 2006-299366 A JP 2001-131760 A

  As described above, in the prior basic technology, the electroless copper plating is performed after the non-conductive substrate is brought into contact with the pretreatment liquid containing the copper nanoparticles miniaturized to 250 nm or less to give the catalyst. On the other hand, as shown in Patent Documents 1 to 6, various chemical treatments are performed before and after applying the catalyst from the viewpoint of improving the appearance and adhesion of the plating film.

  In the present invention, as shown in Patent Documents 1 to 6, a predetermined chemical treatment is performed before and after the catalyst application by the copper nanoparticles refined to a specific particle size or less that forms the core of the preceding basic technology. By combining them in combination, the technical problem is to increase the certainty of the catalyst application of the copper nanoparticles and to form a thicker copper plating film.

  If the non-conductive substrate is treated in advance with a liquid containing a predetermined nitrogen-containing compound, a surfactant, a reducing agent, etc. before the catalyst is imparted by the copper nanoparticles, the present applicant can further absorb the catalyst nucleus in the next step. It is possible to increase the density of catalyst application by accelerating, and when the substrate subjected to the catalyst application treatment is treated with a solution containing an acid or a reducing agent, the catalyst application activity of the substrate can be improved, so that the chemical treatment is performed before and after the catalyst application. The present invention has been completed by finding that the deposition rate of the electroless copper plating film can be increased and the film can be formed thicker than in the case where the electroless plating is not performed.

That is, the present invention 1 includes (a) nonionic surfactant, anionic surfactant, cationic surfactant, amphoteric surfactant, thiazole, benzothiazole, methylbenzothiazole, mercaptobenzothiazole, triazole, tolyltriazole Benzotriazole, methylbenzotriazole, imitazole, 2-undecylimidazole, 2-heptadecylimidazole, benzimidazole, guanidines, thioureas, phthalocyanines, formaldehyde, amineboranes, hypophosphorous acids, ascorbic acid, glyoxalic acid, An adsorption promoting step of immersing the non-conductive substrate in a liquid containing at least one adsorption promoter selected from the group consisting of formic acid ;
(B) 1 to 80% by weight of copper nanoparticles having an average particle diameter of 1 to 250 nm in a solvent by a dispersant selected from a high-molecular surfactant, a low-molecular surfactant, and an aqueous inorganic dispersant composed of tripolyphosphoric acid. Before preparing the pretreatment liquid by dispersing the non-conductive substrate subjected to the adsorption promotion treatment and immersing the non-conductive substrate in the pretreatment liquid on the surface of the substrate to adsorb the copper nanoparticles contained in the pretreatment liquid. Processing steps;
(D) comprising an electroless plating step of forming a copper film on the pretreated substrate using an electroless copper plating solution ,
The electroless copper plating method is characterized in that the non -conductive substrate is a resin substrate or a glass substrate .

The present invention 2 comprises (b) a copper nanoparticle having an average particle diameter of 1 to 250 nm in a solvent by a dispersant selected from a high-molecular surfactant, a low-molecular surfactant, and an aqueous inorganic dispersant composed of tripolyphosphoric acid. Before preparing a pretreatment liquid by dispersing at a content of 1 to 80% by weight, immersing the non-conductive substrate in the pretreatment liquid, and adsorbing the copper nanoparticles contained in the pretreatment liquid on the substrate surface Processing steps;
(C) Containing at least one activator selected from the group consisting of hydrochloric acid, sulfuric acid, carboxylic acid, sulfonic acid, formaldehyde, amine boranes, borohydride compounds, hypophosphorous acids, ascorbic acid, glyoxalic acid, formic acid A post-treatment step of immersing the non-conductive substrate pre-treated in the liquid;
(D) comprising an electroless plating step of forming a copper film on the post-treated substrate using an electroless copper plating solution ,
The electroless copper plating method is characterized in that the non -conductive substrate is a resin substrate or a glass substrate .

The present invention 3 includes (a) nonionic surfactant, anionic surfactant, cationic surfactant, amphoteric surfactant, thiazole, benzothiazole, methylbenzothiazole, mercaptobenzothiazole, triazole, tolyltriazole, benzo From triazole, methylbenzotriazole, imitazole, 2-undecylimidazole, 2-heptadecylimidazole, benzimidazole, guanidines, thioureas, phthalocyanines, formaldehyde, amineboranes, hypophosphorous acids, ascorbic acid, glyoxalic acid, formic acid An adsorption promoting step of immersing the non-conductive substrate in a liquid containing at least one adsorption promoter selected from the group consisting of:
(B) 1 to 80% by weight of copper nanoparticles having an average particle diameter of 1 to 250 nm in a solvent by a dispersant selected from a high-molecular surfactant, a low-molecular surfactant, and an aqueous inorganic dispersant composed of tripolyphosphoric acid. Before preparing the pretreatment liquid by dispersing the non-conductive substrate subjected to the adsorption promotion treatment and immersing the non-conductive substrate in the pretreatment liquid on the surface of the substrate to adsorb the copper nanoparticles contained in the pretreatment liquid. Processing steps;
(C) Containing at least one activator selected from the group consisting of hydrochloric acid, sulfuric acid, carboxylic acid, sulfonic acid, formaldehyde, amine boranes, borohydride compounds, hypophosphorous acids, ascorbic acid, glyoxalic acid, formic acid A post-treatment step of immersing the non-conductive substrate pre-treated in the liquid;
(D) comprising an electroless plating step of forming a copper film on the post-treated substrate using an electroless copper plating solution ,
The electroless copper plating method is characterized in that the non -conductive substrate is a resin substrate or a glass substrate .

Invention 4 is the invention according to any one of the inventions 1 to 3, wherein the content of the dispersant with respect to the copper nanoparticles is 3 to 70% by weight,
An electroless copper plating method, wherein the solvent is an organic solvent having a boiling point of 250 ° C. or lower and a flash point of 10 ° C. or higher at normal pressure, or water, and the pH of the pretreatment liquid is 3.0 to 10.0. is there.

In the basic technology of the present invention, in order to prepare a dispersion using copper nanoparticles refined to a particle size of 250 nm or less, a non-conductive substrate selected from a resin substrate and a glass substrate is immersed, and then electroless When copper plating is performed, a beautiful copper film can be formed on the entire surface of the substrate.
In the present invention, after imparting a metallic copper catalyst nucleus using copper nanoparticles refined to a predetermined particle size or less (that is, pretreatment), in performing electroless copper plating, the pretreatment is further applied in a weighted manner. In order to promote the adsorption of copper nanocatalysts in advance, the copper deposition density during electroless plating increases, compared to the case of electroless plating without chemical treatment before catalyst application. Thus, the deposition rate of the electroless copper plating film can be increased, and the film thickness obtained within the unit plating time can be increased.
In addition, after the pre-treatment, activation treatment (post-treatment) is performed to remove the surface oxidation of the copper nano-catalyst and improve the activity of imparting the catalyst, thus eliminating copper deposition defects during electroless plating. The deposition rate can be increased and the resulting electroless copper plating film can be increased.
Furthermore, in the case where both the adsorption promotion treatment and the activation treatment are combined before and after the pretreatment, the copper deposited film at the time of electroless plating can be made thicker efficiently.
Therefore, when combined with adsorption promotion treatment or post-treatment with an activator before and after pretreatment, a uniform and beautiful copper film can be formed on the entire surface of the non-conductive substrate, and the deposition rate of the plating film is increased. A film increasing effect is obtained.

In the present invention, first, when a catalyst is applied (pretreatment) using a pretreatment liquid in which appropriately refined copper nanoparticles are dispersed, pretreatment is performed when electroless copper plating is performed on a nonconductive substrate. Is an electroless copper plating method in which the substrate is immersed in an adsorption accelerator-containing liquid prior to the adsorption promotion treatment. Second, the substrate is immersed in the activator-containing liquid after the pretreatment to activate This is an electroless copper plating method in which an activation treatment is performed (that is, an activation treatment is interposed between the pretreatment and the electroless plating treatment). Third, adsorption promotion treatment and activation treatment before and after the pretreatment This is an electroless copper plating method that combines the above.
The non-conductive substrate means a resin substrate such as glass / epoxy resin, glass / polyimide resin, epoxy resin, polyimide resin, polycarbonate resin, ABS resin, PET resin , or glass substrate.

The present invention 1 is an electroless copper plating method comprising (a) an adsorption promotion step, (b) a pretreatment step, and (d) an electroless plating step, using an adsorption promoter prior to the pretreatment. It is characterized in that the adsorption promoting process is performed on the non-conductive substrate.
The adsorption promoters are broadly classified into (1) heteromonocyclic, condensed heterocyclic or thiourea-based nitrogen compounds, (2) phthalocyanines, (3) surfactants, and (4) reducing agents. Use alone or in combination.

The nitrogen-containing compound (1) is classified into a heteromonocyclic compound, a condensed heterocyclic compound, and a thiourea compound.
Examples of the heterocyclic monocyclic nitrogen-containing compounds include thiazoles such as thiazole, triazoles such as triazole and tolyltriazole, imidazoles such as imitazole, 2-undecylimidazole, and 2-heptadecylimidazole .
Examples of condensed heterocyclic nitrogen-containing compounds include benzothiazoles such as benzothiazole, methylbenzothiazole and mercaptobenzothiazole, benzotriazoles such as benzotriazole and methylbenzotriazole, and benzimidazole .
Examples of the nitrogen-containing compound based on the heteromonocyclic compound include pyrimidine and triazine 6-membered heteromonocyclic compounds, and 5-membered heteromonocyclic compounds such as thiazole, triazole, and imitazole are preferable.
Similarly, examples of the nitrogen-containing compounds of the above-mentioned condensed heterocyclic compound system include 6-membered condensed heterocyclic compounds of quinoxaline, but 5-membered condensed heterocyclic compounds such as henzothiazole, benzotriazole, and benzimitazole. A compound (a cyclic compound in which a 5-membered heteromonocycle and a benzene ring are condensed) is preferable.
Further, thiourea-based nitrogen-containing compounds include guanidines and thioureas . Examples of guanidines include guanidine, polyallylguanidine hydrochloride having many allyl groups bonded to guanidine, and the like. Examples of thioureas include thiourea or thiourea derivatives such as dimethylthiourea, trimethylthiourea, diethylthiourea, allylthiourea, acetylthiourea, ethylenethiourea, diphenylthiourea, thiourea dioxide, and thiosemicarbazide.
On the other hand, the phthalocyanine of the above (2) is not a metal phthalocyanine coordinated with a metal, but a compound in which a metal is not coordinated.

The surfactant (3) is roughly classified into a high molecular surfactant having a molecular weight of 2,000 to 1,000,000, a low molecular surfactant having a molecular weight of less than 2,000, and an inorganic surfactant.
The above surfactants can be classified into nonionic, anionic, cationic and amphoteric. Moreover, when these are classified from different aspects, they become high-molecular or low-molecular surfactants and inorganic surfactants.
For example, among polymer surfactants, there are anionic polymer surfactants for aqueous systems such as polycarboxylic acids and naphthalene sulfonic acid formalin condensation systems, and for organic solvents such as polycarboxylic acid partial alkyl ester systems. .
Cationics include organic solvent-based polymeric surfactants such as cationic diallylamine polymers and polyalkylenepolyamines.
Nonionic properties include polymer surfactants for water-based polyethylene glycol and other organic solvents such as polyether.
Amphoteric surfactants include amphoteric diallylamine polymers.
Among the low molecular surfactants, there are anionic low molecular surfactants for aqueous systems such as alkylsulfonic acid type.
Cationics include low molecular surfactants for aqueous systems such as quaternary ammonium salts and organic solvents such as alkylpolyamines.
Nonionics include low molecular surfactants for aqueous systems such as higher alcohol alkylene oxides and organic solvents such as polyhydric alcohol esters.
Examples of amphoteric surfactants include carboxybetaine, sulfobetaine, imidazoline betaine, and aminocarboxylic acid.
Examples of the inorganic surfactant include aqueous surfactants such as tripolyphosphate.
Surfactant (3) includes cationic diallylamine polymer, amphoteric diallylamine polymer, dioctylsulfosuccinate, alkylnaphthalenesulfonate, dialkyldimethylammonium chloride, lauryldimethylaminoacetic acid betaine, polyoxyethylene styrenated phenyl ether, etc. Is preferred.

Examples of the reducing agent (4) include formaldehyde, amine boranes, hypophosphorous acids, borohydrides, hydrazine derivatives, ascorbic acid, glyoxalic acid and formic acid .
Examples of the amine boranes include dimethylamine borane, trimethylamine borane, isopropylamine borane, morpholine borane and the like.
Examples of the hypophosphorous acid include hypophosphorous acid and salts thereof such as ammonium, lithium, sodium, potassium, and calcium.
Examples of the borohydrides include sodium borohydride.
Examples of the hydrazine derivative include hydrazine hydrate and phenylhydrazine.
Also, hydroquinone, catechol, resorcin, phloroglucin, cresol sulfonic acid, phenol sulfonic acid, catechol sulfonic acid, hydroquinone sulfonic acid or salts thereof can be expected to be effective.

In the adsorption promoting step (a) of the present invention 1, the non-conductive substrate is immersed in the liquid containing the adsorption promoter.
The density | concentration with respect to the liquid containing an adsorption accelerator is 0.01-300 g / L, Preferably it is 0.01-200 g / L, More preferably, it is 0.01-100 g / L.
If the adsorption promoter is less than 0.01 g / L, the function of promoting adsorption of copper nanoparticles cannot be exhibited, and even if the amount is increased from 300 g / L, the adsorption promotion function is not significantly changed.

Next, in the pretreatment step (b) of the present invention 1, a pretreatment liquid is prepared by dispersing copper nanoparticles having an average particle diameter of 1 to 250 nm in a solvent at a content of 1 to 80% by weight with a dispersant. Then, the non-conductive substrate that has been subjected to the adsorption promotion treatment is immersed in the pretreatment liquid, and the copper nanoparticles contained in the pretreatment liquid are adsorbed on the substrate surface.
The pretreatment liquid includes copper nanoparticles, a dispersant, and a solvent.
The copper nanoparticles of the present invention contained in the pretreatment liquid are fine particles having an average particle diameter of 1 to 250 nm, preferably an average particle diameter of 1 to 150 nm, and more preferably an average particle diameter of 1 to 120 nm.
When copper nanoparticles having a particle size of 250 nm or less are mixed with a solvent as compared with copper particles having a larger particle size, the dispersion system is truly stabilized in the presence of a dispersant, and this dispersion system (that is, the pretreatment liquid) ), It can be presumed that the anchor effect promotes the application of copper catalyst nuclei on the surface of the non-conductive substrate.
On the contrary, if the average particle size is larger than 250 nm, aggregation, precipitation or separation occurs, and a stable dispersion cannot be obtained, or the appearance is stable and the anchor effect cannot be expected. Even if the non-conductive substrate is immersed in the pretreatment liquid, the copper catalyst cannot be applied or only partially applied.
Copper nanoparticles that meet the requirements of the present invention are readily available from commercial products.

The dispersant to be mixed with the pretreatment liquid is for peptizing the copper nanoparticles in pieces and stably dispersing the loosened particles without agglomerating, and the surfactant described as a component of the adsorption accelerator and The same can be used.
That is, the dispersant is roughly classified into a high molecular dispersant having a molecular weight of 2,000 to 1,000,000, a low molecular dispersant having a molecular weight of less than 2000, and an inorganic dispersant.
The polymer dispersant is highly dispersed in a small amount, can be expected to have a repulsive effect due to steric hindrance, and can be classified into anionic, cationic, and nonionic.
Although the low molecular weight dispersant is excellent in the wetting action that is easily adsorbed on the surface of the copper nanoparticles, the dispersion stabilizing action does not reach that of the polymer dispersing agent, and can be classified into anionic, cationic, and nonionic properties.
The inorganic dispersant is strongly adsorbed on the particle surface in an aqueous system and has a stabilizing effect due to electrostatic repulsion, and there is an aqueous dispersant composed of tripolyphosphoric acid and a salt thereof .

Therefore, the above-mentioned dispersants are explained by upper conceptual specific examples. Amine, polyester, carboxylic acid, carboxylic acid ester, phosphoric acid, phosphoric acid ester and salts thereof, alkylol ammonium salt, alkyl ammonium salt, linear alkyl ether , Polyether, polyurethane, polyacrylate, polysiloxane .
In this case, the amine includes alkylamines, monoamines, polyamines, etc., the phosphoric acids are phosphoric acid and salts thereof, and the phosphoric acid includes polyphosphoric acid.
In addition, the intermediate conceptual specific examples include alkyl ammonium salts of block copolymers containing acid groups, alkylol ammonium salts of high molecular weight acidic polymers, alkylol ammonium salts of polyfunctional polymers, star-structure-modified polyalkoxys. Rate, salt of long-chain polyaminoamide and acid polymer, polycarboxylate of polyaminoamide, salt of long-chain polyaminoamide and polar acid ester, hydroxyl group-containing carboxylic acid ester, alkylol aminoamide, unsaturated polycarboxylic acid polyaminoamide, An alkyl ammonium salt of an acidic polymer, a modified acrylic block copolymer, a combination of a polar acid ester and a polymer alcohol, an unsaturated polycarboxylic acid polymer, a combination of an unsaturated acidic polycarboxylic acid polyester and polysiloxane, and the like are preferable.
Furthermore, as subordinate conceptual specific examples of the dispersant, polyoxyethylene dodecyl ether phosphate ester, polyoxyethylene alkyl ether phosphate ester / monoethanolamine salt, disodium polyoxyethylene alkylsulfosuccinate, polyvinyl pyrrolidone, polyethylene It is preferable to select from the group consisting of glycol, polypropylene glycol, polyvinyl alcohol, quaternized alkylimidazoline, and polyphosphoric acid .

   Commercially available products of the polymer dispersant include Solsparse 3000, Solspers 5000, Solspers 9000, Solspers 12000, Solspers 13240, Solspers 17000, Solspers 20000, Solspers 24000, Solspers 26000, Solspers 27000, Solspers 28000, Solspers 41090 (and above, Japan) Lubrizol Corporation), Dispersic 101, Dispersic 102, Dispersic 103, Dispersic 106, Dispersic 108, Dispersic 109, Dispersic 110, Dispersic 111, Dispersic 112, Dispersic 116, Dispersic 130, Dispersic 140, Superbic 142, Dispersic 145, Dispersic 161, Dispersic 162, Dispersic 163, Dispersic 166, Dispersic 167, Dispersic 168, Dispersic 170, Dispersic 171, Dispersic 174, Dispersic 180, Dispersic 182, Dispersic-183, Dispersic 184, Dispersic 185, Dispersic 187, Dispersic 190, Dispersic 191, Dispersic 192, Dispersic 193, Dispersic 194, Dispersic 198, Dispersic 199, Dispersic 2000 , Disperbic-2001, Disperbic 2008, Disper 2009, Dispersic 2010, Dispersic 2012, Dispersic 2022, Dispersic 2025, Dispersic 2050, Dispersic 2070, Dispersic 2090, Dispersic 2091, Dispersic 2095, Dispersic 2096, Dispersic 2150, Dispersic 2155, ANTI-TERRA-U (manufactured by Big Chemie Japan), polymer 100, polymer 120, polymer 150, polymer 400, 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-4540, EFKA-4550 (manufactured by EFKA Chemical Co., Ltd.), FLOREN DOPA-158, FLOREN DOPA-22, FLOREN DOPA-17, FLOREN G-700, FLOREN TG-720W, FLOREN-730W, FLOREN-740W, Floren-745W (above, manufactured by Kyoeisha Chemical Co., Ltd.), Ajisper PA-111, Azisper PN411, Azisper PB821, Azisper PB822, Azisper PB881 (above, Ajinomoto Co., Inc.), Disparon 1210, Disparon 2150, Disparon KS-860, Disparon KS -873N, Disparon 7004, Disparon 1831, Disparon 1850, Disparon 1860, Disparon DA-1401, Disparon PW-36, Spalon DN-900, Disparon DA-1200, Disparon DA-550, Disparon DA-7301, Disparon DA-325, Disparon DA-375, Disparon DA-234 (above, manufactured by Enomoto Kasei Co., Ltd.), SN Dispersant 5020, SN Dispar Santo 5027, SN Dispersant 5029, SN Dispersant 5034, SN Dispersant 5040, SN Dispersant 5045, SN Dispersant 5468, SN Dispersant 9228, SN Sparse 70, SN Sparse 2190, SN Wet L, SN Wet 366, Nop Cospers 44-C, Nopco Wet 50, Nopco Santo RFA (above, manufactured by San Nopco), Price Surf A215C, Price Surf A212C, Pricer Off M208F (manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd.) and the like.

  For example, the above ANTI-TERRA-250 is alkylol ammonium salt type, Dispersic 180 is phosphate ester type, Dispersic 182-185, 198 is polyurethane type, Dispersic 187, 190-191, 194, 199, 2010, 2012 , 2015 is a polyacrylate type.

The solvent used in the pretreatment liquid is preferably water or an organic solvent having a boiling point of 250 ° C. or lower and a flash point of 10 ° C. or higher at normal pressure (see the present invention 4) from the viewpoint of safety and the like. It is selected from 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 truly stabilized by using the copper nanoparticles of the present invention, but from the viewpoint of promoting this stabilization, the solvent of the present invention is preferably a polar solvent, and further, an oxygen-containing compound, or A polar solvent comprising an acidic group-containing compound is more preferred.
Subconceptual specific examples 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, 2-butoxyethyl acetate, ethylene glycol butyl ether, propylene glycol monomethyl ether acetate, diethylene glycol monoethyl ether acetate, 2-ethoxyethyl acetate, ethylene glycol diacetate, N, N-dimethylformamide, dimethyl sulfoxide, N-methyl-2-pyrrolidone , And preferably selected from the group consisting of propylene carbonate.
Further, methoxypropyl acetate, butyl acetate, dipropylene glycol monomethyl ether, tripropylene glycol monomethyl ether, butyrocellosolve, etc. are also effective.

The pretreatment liquid of the present invention is prepared by mixing a dispersant with a solvent, and then mixing and stirring the copper nanoparticles. From the viewpoint of dispersion stability, pH 3.0 to 10.0 is preferable (Invention 4). reference).
In the above stirring, it is not necessary to stir particularly strongly or for a long time. The liquid temperature during mixing and stirring may be room temperature.
In addition, the pretreatment liquid includes an antioxidant for preventing the surface oxidation of copper particles, various acids such as hydrochloric acid, sulfuric acid, acetic acid, and oxalic acid, various kinds such as sodium hydroxide, potassium hydroxide, aqueous ammonia, and amine. It goes without saying that various additives such as a pH adjuster made of a base or an anionic, cationic or nonionic surfactant can be contained.

In the pretreatment liquid of the present invention, the content of copper nanoparticles with respect to the total amount of the liquid is 1 to 80% by weight, preferably 5 to 70% by weight. If the amount is less than 1% by weight, it is difficult to uniformly adsorb the copper nanoparticles on the substrate. If the amount exceeds 80% by weight, it becomes difficult to form a stable dispersion even if a dispersant is used.
In the pretreatment liquid of the present invention, the content of the dispersant with respect to the copper nanoparticles is preferably 3 to 70% by weight (see the present invention 4), and 3 to 50% by weight, although it depends on the type of the dispersant. More preferred. If the amount is less than 3% by weight, it is not easy to form a stable dispersion. If the amount is more than 70% by weight, impurities may be mixed in the electroless copper film after application of the catalyst.
In the pretreatment step (b), the liquid temperature when the nonconductive substrate is immersed in the pretreatment liquid is generally 5 to 70 ° C., preferably 10 to 50 ° C., and the immersion time is 1 to 20 minutes. Non-conductive substrates are as described above, including glass / epoxy resin substrates.
The nonconductive substrate immersed in the pretreatment liquid is washed and then dried or transferred to the next electroless copper plating step (d) without drying.

In the electroless plating step (d) of the present invention 1, a copper film is formed on the pretreated substrate using an electroless copper plating solution.
In this electroless copper plating process, it may be processed in the same manner as in the prior art, and there are no particular restrictions. The temperature of the electroless copper plating solution is generally 15 to 70 ° C, preferably 20 to 60 ° C.
In stirring the copper plating solution, air stirring, rapid liquid flow stirring, mechanical stirring using a stirring blade, or the like can be used.

There is no particular limitation on the composition of the electroless copper plating solution, 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.
Any soluble salt (A) may be used as long as it is a soluble salt that generates cuprous or cupric ions in an aqueous solution, and there is no particular limitation, and hardly soluble salts are not excluded. Specific examples include copper sulfate, copper oxide, copper chloride, copper carbonate, copper acetate, copper pyrophosphate, copper oxalate, and the like, with copper sulfate and copper oxide being preferred.

  The reducing agent contained in the electroless copper plating solution includes formaldehyde (formalin water), hypophosphorous acid, phosphorous acid, amine boranes, borohydrides, glyoxylic acid, etc., and formalin water is preferred.

  The complexing agent contained in the electroless copper plating solution is ethylenediaminetetraacetic acid (EDTA), diethylenetriaminepentaacetic acid (DTPA), triethylenetetraminehexaacetic acid (TTHA), hydroxyethylethylenediaminetriacetic acid (HEDTA), nitrilotriacetic acid ( NTA), aminocarboxylic acids such as iminodiacetic acid (IDA), polyamines such as ethylenediamine, tetramethylenediamine, hexamethylenediamine, diethylenetriamine, tetraethylenepentamine, pentaethylenehexamine, monoethanolamine, diethanolamine, triethanolamine, etc. Examples thereof include amino alcohols, citric acid, tartaric acid, oxycarboxylic acids such as lactic acid and malic acid, thioglycolic acid, and glycine.

As described above, an additive such as a surfactant may be contained in the electroless copper plating solution. In this case, the surfactant includes polyethylene glycol, polypropylene glycol, polyoxyethylene-polyoxypropylene random copolymer, polyoxyethylene. Examples thereof include oxyethylene-polyoxypropylene block copolymers.
The molecular weight of the polymer is generally in the range of 500 to 1,000,000, preferably 1000 to 100,000.
The pH adjuster is as described in the pretreatment liquid.

The electroless copper plating solution may contain an organic acid and 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 borofluoric 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.

On the other hand, the present invention 2 is an electroless copper plating method comprising (b) a pretreatment step, (c) a posttreatment step with an activator, and (d) an electroless plating step, and is activated after the pretreatment. It is characterized in that it is applied to electroless copper plating through a post-treatment using an agent.
The activators are roughly classified into (1) acids and (2) reducing agents , which are used alone or in combination.
Examples of the acid (1) include hydrochloric acid, sulfuric acid, nitric acid, oxalic acid, carboxylic acid, organic sulfonic acid, sulfosuccinic acid, and sulfamic acid .
Reducing agent of (2) is basically the use of a reducing agent used in the adsorption promoting agents, like formaldehyde, amine boranes, borohydride compound, hypophosphorous acid, ascorbic acid, glyoxalic acid, such as formic acid It is done.
In this post-treatment step (c), the pretreated non-conductive substrate is immersed in the liquid containing the activator.
The content of the activator in the liquid is 0.01 to 300 g / L, preferably 0.01 to 200 g / L, more preferably 0.01 to 100 g / L.
When the activator is less than 0.01 g / L, the function of removing the surface oxidation of the catalyst core of the copper nanoparticles is lowered, and when it is more than 300 g / L, impurities may be mixed into the film obtained by the next electroless plating. There is.
And the said post-processed board | substrate transfers to the following electroless-plating process (d).
The electroless plating step (d) is as described in the same step of the first invention.

Next, the present invention 3 provides an electroless copper plating method comprising: (a) an adsorption promoting step; (b) a pretreatment step; (c) a posttreatment step with an activator; and (d) an electroless plating step. This is characterized in that, prior to the pretreatment, the non-conductive substrate is subjected to adsorption promotion treatment using an adsorption promoter, and post-treatment using an activator is performed on the substrate after the pretreatment.
The adsorption promoting step (a) is as described in the same step of the present invention 1, and the post-processing step (c) is as described in the same step of the present invention 2.
In the present invention 3, in order to combine the adsorption promotion treatment and the post-treatment before and after the pretreatment, compared to the present invention 1 or the present invention 2 in which either the adsorption promotion treatment or the post-treatment is combined before or after the pretreatment, The reliability of copper nanoparticle catalyst application increases (the density of catalyst application increases) and the decrease in the active function of the catalyst core before plating can be eliminated, resulting in a faster deposition rate of the copper film in electroless plating The film increasing effect can be expected more.
Between the steps of the present invention 1 to 3, the substrate after the predetermined processing is basically cleaned, but the cleaning can be omitted. For the washing, water (selectable from warm water to cold water) may be used, or alcohols, acetone, or various solvents listed for the pretreatment liquid may be used. Further, in the case of washing (especially washing with water), it is fundamental to proceed to the next step without drying, but it is also possible to perform a drying treatment. The drying may be performed with cold air or hot air. For example, in consideration of suppression of damage to the resin of the resin substrate, the temperature is 150 ° C. or lower, preferably 80 ° C. or lower, when using cold air or hot air. Preferably it is 60 degrees C or less.

Examples of the electroless copper plating method of the present invention in which electroless plating is performed by combining the adsorption promoting step and / or the post-processing step before and after the pretreatment step, and electroless plating is applied to the resin substrate. Test examples of the appearance evaluation and film thickness of the obtained copper film will be sequentially described. In the examples, “%” is based on weight.
The present invention is not limited to the above-described examples and test examples, and it is needless to say that arbitrary modifications can be made within the scope of the technical idea of the present invention.

<< Example of electroless copper plating method >>
Among Examples 1 to 23 below, Examples 1 to 14 are examples of adsorption promotion treatment → pretreatment → electroless copper plating, and Examples 1 and 3 use an anionic surfactant as an adsorption accelerator. Examples, Example 2 is also an example using a nonionic surfactant, Examples 4 and 6 are examples using a cationic surfactant, Examples 5 and 7 are examples using an amphoteric surfactant, Examples Examples 8 to 9 are examples using a reducing agent, Examples 10 to 11 are examples using a 5-membered condensed heterocyclic nitrogen-containing compound, Example 12 is an example using phthalocyanine, Examples 13 to 14 are thiourea series This is an example using the nitrogen-containing compound.
Examples 15 to 20 are examples of pretreatment → post treatment → electroless copper plating, Example 15 is an example using an acid as an activator, and Examples 16 to 20 are examples using a reducing agent. .
Examples 21 to 23 are examples of adsorption promotion treatment → pretreatment → post treatment → electroless copper plating, and Example 21 uses a nonionic surfactant as an adsorption promoter and a reducing agent as an activator. Example, Example 22 is an example using an anionic surfactant as an adsorption accelerator and a reducing agent as an activator, Example 23 is active using a 5-membered condensed heterocyclic nitrogen-containing compound as an adsorption accelerator This is an example in which a reducing agent is used as the agent.

On the other hand, in Reference Example 1, as in the preceding basic technology, no special chemical treatment is performed before or after the pretreatment step in which the pretreatment liquid is applied to the resin substrate, and the electroless copper plating is immediately performed after the pretreatment. This is an example (ie, pretreatment → electroless copper plating).
Comparative Examples 1 and 2 are examples of pretreatment using copper nanoparticles having a particle size larger than the appropriate range of the present invention based on the above Reference Example 1, and Comparative Example 1 is an example having a particle size of 500 nm. Comparative Example 2 is an example having a particle size of 300 nm.

(1) Example 1
After preliminarily roughening the resin substrate (desmear treatment), the adsorption promotion treatment is performed under the following condition (a), and then the pretreatment is performed under the condition (b), followed by the condition (d). Electroless copper plating was performed.
(A) Adsorption promotion step First, in a double-sided copper-clad glass / epoxy resin substrate (FR-4 manufactured by Panasonic Electric Works Co., Ltd., plate thickness: 1.0 mm), a sample substrate obtained by dissolving and removing a 35 μm copper foil is used. did.
A liquid containing the adsorption accelerator was prepared with the following composition.
[Adsorption accelerator-containing liquid]
Dioctyl sodium sulfosuccinate 10g / L
(B) Pretreatment process The copper nanoparticle and the dispersing agent were mixed and stirred in a solvent (mixture of pure water and an organic solvent) with the following composition to prepare a pretreatment liquid.
[Pretreatment liquid]
Copper nanoparticles 5.0g
DISPERBYK-180 1.0g
2.6g of pure water
Isopropyl alcohol 2.5g
The copper nanoparticles have a particle size of 80 nm, DISPERBYK-180 is a dispersant manufactured by Big Chemie Japan, and has as its main component an alkyl ammonium salt of a block copolymer containing acid groups.
In this case, the content of the copper nanoparticles with respect to the total amount of the liquid is 45%, and the content of the dispersant with respect to the copper nanoparticles is 20%. The pH was 6.5.
(D) Electroless copper plating step An electroless copper plating solution was constructed with the following composition. The plating solution was pH adjusted with the following sodium hydroxide.
[Electroless copper plating solution]
Copper sulfate pentahydrate (as Cu2 +) 2.0g
Formaldehyde 5.0g
EDTA 30.0g
Sodium hydroxide 9.6g
Residual pure water pH (20 ° C) 12.8
After immersing the sample substrate in the liquid containing the adsorption promoter (a) at 25 ° C. for 5 minutes and washing with pure water, the substrate whose adsorption was promoted was subjected to the above condition (b) at 30 ° C. for 5 minutes. After immersing in the pretreatment liquid and washing with pure water, electroless plating is performed at 50 ° C. for 5 minutes in the electroless copper plating liquid of (d) to form a copper film on the sample substrate. After forming, it was washed with pure water and dried.
The film thickness of the obtained copper plating film was 0.30 μm.

(2) Example 2
Based on the above Example 1, the treatment was performed under the same conditions as in Example 1 except that the liquid containing the adsorption accelerator was prepared with the following composition.
[Adsorption accelerator-containing liquid]
Polyoxyethylene styrenated phenyl ether (EO23 mol) 7g / L
The film thickness of the obtained copper plating film was 0.27 μm.

(3) Example 3
Based on the above Example 1, the treatment was performed under the same conditions as in Example 1 except that the liquid containing the adsorption accelerator was prepared with the following composition.
[Adsorption accelerator-containing liquid]
Sodium alkylnaphthalene sulfonate 5g / L
The film thickness of the obtained copper plating film was 0.32 μm.

(4) Example 4
Based on the above Example 1, the treatment was performed under the same conditions as in Example 1 except that the liquid containing the adsorption accelerator was prepared with the following composition.
[Adsorption accelerator-containing liquid]
Distearyldimethylammonium chloride 5g / L
The film thickness of the obtained copper plating film was 0.28 μm.

(5) Example 5
Based on the above Example 1, the treatment was performed under the same conditions as in Example 1 except that the liquid containing the adsorption accelerator was prepared with the following composition.
[Adsorption accelerator-containing liquid]
Lauryldimethylaminoacetic acid betaine 10g / L
The film thickness of the obtained copper plating film was 0.26 μm.

得られた銅メッキ皮膜の膜厚は０.２８μｍであった。 (6) Example 6
Based on the above Example 1, the treatment was performed under the same conditions as in Example 1 except that the liquid containing the adsorption accelerator was prepared with the following composition.
[Adsorption accelerator-containing liquid]
Diallyldimethylammonium chloride polymer 5g / L
The polymer is represented by the following structural formula.

The film thickness of the obtained copper plating film was 0.28 μm.

得られた銅メッキ皮膜の膜厚は０.３０μｍであった。 (7) Example 7
Based on the above Example 1, the treatment was performed under the same conditions as in Example 1 except that the liquid containing the adsorption accelerator was prepared with the following composition.
[Adsorption accelerator-containing liquid]
Diallylamine hydrochloride / maleic acid copolymer 3g / L
The copolymer is represented by the following structural formula.

The film thickness of the obtained copper plating film was 0.30 μm.

(8) Example 8
Based on the above Example 1, the treatment was performed under the same conditions as in Example 1 except that the liquid containing the adsorption accelerator was prepared with the following composition.
[Adsorption accelerator-containing liquid]
Dimethylamine borane 10g / L
The film thickness of the obtained copper plating film was 0.26 μm.

(9) Example 9
Based on the above Example 1, the treatment was performed under the same conditions as in Example 1 except that the liquid containing the adsorption accelerator was prepared with the following composition.
[Adsorption accelerator-containing liquid]
Formaldehyde 10g / L
The film thickness of the obtained copper plating film was 0.26 μm.

(10) Example 10
Based on the above Example 1, the treatment was performed under the same conditions as in Example 1 except that the liquid containing the adsorption accelerator was prepared with the following composition.
[Adsorption accelerator-containing liquid]
Benzotriazole 5g / L
The film thickness of the obtained copper plating film was 0.30 μm.

(11) Example 11
Based on the above Example 1, the treatment was performed under the same conditions as in Example 1 except that the liquid containing the adsorption accelerator was prepared with the following composition.
[Adsorption accelerator-containing liquid]
Benzimidazole 3g / L
The film thickness of the obtained copper plating film was 0.29 μm.

(12) Example 12
Based on the above Example 1, the treatment was performed under the same conditions as in Example 1 except that the liquid containing the adsorption accelerator was prepared with the following composition.
[Adsorption accelerator-containing liquid]
Phthalocyanine (solvent: dimethyl sulfoxide) 1 g / L
The film thickness of the obtained copper plating film was 0.26 μm.

(13) Example 13
Based on the above Example 1, the treatment was performed under the same conditions as in Example 1 except that the liquid containing the adsorption accelerator was prepared with the following composition.
[Adsorption accelerator-containing liquid]
Polyallyl guanidine hydrochloride (solvent: dimethyl sulfoxide) 1 g / L
The film thickness of the obtained copper plating film was 0.27 μm.

(14) Example 14
Based on the above Example 1, the treatment was performed under the same conditions as in Example 1 except that the liquid containing the adsorption accelerator was prepared with the following composition.
[Adsorption accelerator-containing liquid]
Thiourea 15g / L
The film thickness of the obtained copper plating film was 0.26 μm.

(15) Example 15
The resin substrate is preliminarily surface-roughened (desmeared), pre-treated under the following condition (b), then post-treated under condition (c), and then free under condition (d). Electrolytic copper plating was performed.
(B) Pretreatment step First, in a double-sided copper-clad glass / epoxy resin substrate (FR-4 manufactured by Panasonic Electric Works Co., Ltd., plate thickness: 1.0 mm), a sample substrate obtained by dissolving and removing a 35 μm copper foil was used. did.
Meanwhile, a pretreatment liquid was prepared by mixing and stirring copper nanoparticles and a dispersant in a solvent (pure water) having the following composition.
[Pretreatment liquid]
Copper nanoparticles 5.0g
DISPERBYK-180 1.0g
2.6g of pure water
Isopropyl alcohol 2.5g
The copper nanoparticles have a particle size of 80 nm, DISPERBYK-180 is a dispersant manufactured by Big Chemie Japan, and has as its main component an alkyl ammonium salt of a block copolymer containing acid groups.
In this case, the content of the copper nanoparticles with respect to the total amount of the liquid is 45%, and the content of the dispersant with respect to the copper nanoparticles is 20%. The pH was 6.5.
(C) Post-processing process The activator containing liquid was prepared with the following composition.
[Activator-containing liquid]
Sulfuric acid 70g / L
(D) Electroless copper plating step An electroless copper plating solution was constructed with the following composition. The plating solution was pH adjusted with the following sodium hydroxide.
[Electroless copper plating solution]
Copper sulfate pentahydrate (as Cu2 +) 2.0g
Formaldehyde 5.0g
EDTA 30.0g
Sodium hydroxide 9.6g
Residual pure water pH (20 ° C) 12.8
The substrate whose adsorption has been promoted is immersed in the pretreatment liquid (b) at 30 ° C. for 5 minutes, washed with pure water, and then the pretreated substrate is converted into the activator-containing liquid (c). After immersing at 25 ° C. for 5 minutes and washing with pure water, electroless plating is performed in the above-mentioned electroless copper plating solution (d) at 50 ° C. for 5 minutes on the sample substrate. After forming the copper film, it was washed with pure water and dried.
The film thickness of the obtained copper plating film was 0.26 μm.

(16) Example 16
Based on the above Example 15, the treatment was performed under the same conditions as in Example 15 except that the activator-containing liquid was prepared with the following composition.
[Activator-containing liquid]
Dimethylamine borane 20g / L
The film thickness of the obtained copper plating film was 0.34 μm.

(17) Example 17
Based on the above Example 15, the treatment was performed under the same conditions as in Example 15 except that the activator-containing liquid was prepared with the following composition.
[Activator-containing liquid]
Formaldehyde 30g / L
The film thickness of the obtained copper plating film was 0.35 μm.

(18) Example 18
Based on the above Example 15, the treatment was performed under the same conditions as in Example 15 except that the activator-containing liquid was prepared with the following composition.
[Activator-containing liquid]
Ascorbic acid 50g / L
The film thickness of the obtained copper plating film was 0.30 μm.

(19) Example 19
Based on the above Example 15, the treatment was performed under the same conditions as in Example 15 except that the activator-containing liquid was prepared with the following composition.
[Activator-containing liquid]
Formic acid 20g / L
The film thickness of the obtained copper plating film was 0.28 μm.

(20) Example 20
Based on the above Example 15, the treatment was performed under the same conditions as in Example 15 except that the activator-containing liquid was prepared with the following composition.
[Activator-containing liquid]
Hypophosphorous acid 15g / L
The film thickness of the obtained copper plating film was 0.27 μm.

(21) Example 21
After preliminarily roughening the resin substrate (desmear treatment), the adsorption promotion treatment is performed under the following condition (a), then the pretreatment is performed under the condition (b), and the condition (c) is continued. After the post-treatment, electroless copper plating was performed under the condition (d).
(A) Adsorption promotion step First, in a double-sided copper-clad glass / epoxy resin substrate (FR-4 manufactured by Panasonic Electric Works Co., Ltd., plate thickness: 1.0 mm), a sample substrate obtained by dissolving and removing a 35 μm copper foil is used. did.
A liquid containing the adsorption accelerator was prepared with the following composition.
[Adsorption accelerator-containing liquid]
Polyoxyethylene styrenated phenyl ether (EO23 mol) 7g / L
(B) Pretreatment step Copper nanoparticles and a dispersant were mixed and stirred in a solvent (pure water) with the following composition to prepare a pretreatment liquid.
[Pretreatment liquid]
Copper nanoparticles 5.0g
DISPERBYK-180 1.0g
2.6g of pure water
Isopropyl alcohol 2.5g
The copper nanoparticles have a particle size of 80 nm, DISPERBYK-180 is a dispersant manufactured by Big Chemie Japan, and has as its main component an alkyl ammonium salt of a block copolymer containing acid groups.
In this case, the content of the copper nanoparticles with respect to the total amount of the liquid is 45%, and the content of the dispersant with respect to the copper nanoparticles is 20%. The pH was 6.5.
(C) Post-processing process The activator containing liquid was prepared with the following composition.
[Activator-containing liquid]
Formaldehyde 10g / L
(D) Electroless copper plating step An electroless copper plating solution was constructed with the following composition. The plating solution was pH adjusted with the following sodium hydroxide.
[Electroless copper plating solution]
Copper sulfate pentahydrate (as Cu2 +) 2.0g
Formaldehyde 5.0g
EDTA 30.0g
Sodium hydroxide 9.6g
Residual pure water pH (20 ° C) 12.8
After immersing the sample substrate in the liquid containing the adsorption promoter (a) at 25 ° C. for 5 minutes and washing with pure water, the substrate whose adsorption was promoted was subjected to the above condition (b) at 30 ° C. for 5 minutes. The pretreated substrate was immersed in the pretreatment liquid and washed with pure water, and then the pretreated substrate was immersed in the activator-containing liquid (c) at 25 ° C. for 5 minutes and washed with pure water. Thereafter, electroless plating was performed in the electroless copper plating solution (d) at 50 ° C. for 5 minutes to form a copper film on the sample substrate, and then washed with pure water and dried.
The film thickness of the obtained copper plating film was 0.30 μm.

(22) Example 22
Based on the above Example 21, the treatment was performed under the same conditions as in Example 21 except that the liquid containing the adsorption accelerator and the liquid containing the activator were prepared with the following composition.
[Adsorption accelerator-containing liquid]
Sodium alkylnaphthalene sulfonate 5g / L
[Activator-containing liquid]
Hypophosphorous acid 10g / L
The film thickness of the obtained copper plating film was 0.28 μm.

(23) Example 23
Based on the above Example 21, the treatment was performed under the same conditions as in Example 21 except that the liquid containing the adsorption accelerator and the liquid containing the activator were prepared with the following composition.
[Adsorption accelerator-containing liquid]
Benzotriazole 1g / L
[Activator-containing liquid]
Dimethylamine borane 10g / L
The film thickness of the obtained copper plating film was 0.38 μm.

(24) Standard example 1
The resin substrate was preliminarily roughened (desmeared) and then pretreated under the following condition (b), followed by electroless copper plating under the condition (d).
(B) Pretreatment step First, in a double-sided copper-clad glass / epoxy resin substrate (FR-4 manufactured by Panasonic Electric Works Co., Ltd., plate thickness: 1.0 mm), a sample substrate obtained by dissolving and removing a 35 μm copper foil was used. did.
Meanwhile, a pretreatment liquid was prepared by mixing and stirring copper nanoparticles and a dispersant in a solvent (pure water) having the following composition.
[Pretreatment liquid]
Copper nanoparticles 5.0g
DISPERBYK-180 1.0g
2.6g of pure water
Isopropyl alcohol 2.5g
The copper nanoparticles have a particle size of 80 nm, DISPERBYK-180 is a dispersant manufactured by Big Chemie Japan, and has as its main component an alkyl ammonium salt of a block copolymer containing acid groups.
In this case, the content of the copper nanoparticles with respect to the total amount of the liquid is 45%, and the content of the dispersant with respect to the copper nanoparticles is 20%. The pH was 6.5.
(D) Electroless copper plating step An electroless copper plating solution was constructed with the following composition. The plating solution was pH adjusted with the following sodium hydroxide.
[Electroless copper plating solution]
Copper sulfate pentahydrate (as Cu2 +) 2.0g
Formaldehyde 5.0g
EDTA 30.0g
Sodium hydroxide 9.6g
Residual pure water pH (20 ° C) 12.8
A sample substrate is immersed in the pretreatment liquid at 30 ° C. for 5 minutes, washed with pure water, and then electroless plated in the electroless copper plating solution at 50 ° C. for 5 minutes. After forming a copper film on the substrate, it was washed with pure water and dried.
The film thickness of the obtained copper plating film was 0.25 μm.

(25) Comparative Example 1
Based on the above Reference Example 1, it was processed under the same conditions as Reference Example 1 except that the pretreatment liquid was prepared with the following composition.
[Pretreatment liquid]
Copper nanoparticles 5.0g
DISPERBYK-111 0.2g
5.9 g of 3-methoxy-3-methyl-1-butanol
As the copper nanoparticles, particles having an average particle diameter of 500 nm were used. DISPERBYK-111 is a dispersant manufactured by Big Chemie Japan, and has a copolymer containing an acid group as a main component.
However, in Comparative Example 1, no copper film was deposited during electroless plating.

(26) Comparative Example 2
Based on the above Reference Example 1, it was processed under the same conditions as Reference Example 1 except that the pretreatment liquid was prepared with the following composition.
[Pretreatment liquid]
Copper nanoparticles 5.0g
DISPERBYK-111 0.2g
5.9 g of 3-methoxy-3-methyl-1-butanol
As the copper nanoparticles, particles having an average particle diameter of 300 nm were used.
However, in this comparative example 2, as a result of electroless plating, the copper film was only partially deposited on the substrate.

<< External appearance test example of copper film on resin substrate >>
Next, for Examples 1 to 23, Reference Example 1 and Comparative Examples 1 and 2, the copper film obtained by electroless plating on the resin substrate subjected to the adsorption promotion treatment and / or the activation treatment before and after the pretreatment. The appearance was visually observed and the superiority or inferiority was evaluated according to the following criteria.
O: A uniform, smooth and beautiful copper film was obtained by electroless plating.
Δ: Copper film partially deposited.
X: The copper film did not precipitate.

<< Appearance evaluation of copper film and film thickness test result >>
The results of the copper film appearance evaluation test are shown in Table A below. In Table A below, the film thickness (μm) of the copper film obtained by electroless plating is also shown. About the said film thickness, what was described in each end of the said Examples 1-23 and the reference example 1 was transcribed.
As described above, in Comparative Example 1, no copper film was deposited, and thus the film thickness was not measurable. In Comparative Example 2, the copper film was only partially deposited and was insufficient from the standpoint of obtaining a practical film, so the film thickness was not measured. About Comparative Examples 1-2, "-" of the column of a film thickness shows these things.

[Table A] Plating appearance Film thickness (μm) Plating appearance Film thickness (μm)
Example 1 ○ 0.30 Example 14 ○ 0.26
Example 2 ○ 0.27 Example 15 ○ 0.26
Example 3 ○ 0.32 Example 16 ○ 0.34
Example 4 ○ 0.28 Example 17 ○ 0.35
Example 5 ○ 0.26 Example 18 ○ 0.30
Example 6 ○ 0.28 Example 19 ○ 0.28
Example 7 ○ 0.30 Example 20 ○ 0.27
Example 8 ○ 0.26 Example 21 ○ 0.30
Example 9 ○ 0.26 Example 22 ○ 0.28
Example 10 ○ 0.30 Example 23 ○ 0.38
Example 11 ○ 0.29 Reference Example 1 ○ 0.25
Example 12 ○ 0.26 Comparative Example 1 × −−
Example 13 ○ 0.27 Comparative Example 2 Δ −−

<< Comprehensive evaluation of test results >>
(1) In Comparative Examples 1 and 2 in which the resin substrate was pretreated using copper nanoparticles having a particle size larger than the appropriate range of the present invention, the copper film was not deposited at all or was only partially deposited.
On the other hand, in Reference Example 1 in which the resin substrate was pretreated using copper nanoparticles appropriately refined to 250 μm or less and electroless copper plating was performed, a uniform film was obtained on the entire substrate, and the film thickness was Was 0.25 μm.
On the other hand, in Examples 1 to 14 in which the pretreatment and the electroless plating treatment are premised and the adsorption promotion treatment is combined prior to the pretreatment, a uniform film is obtained on the entire substrate, and the copper film is all formed. Thus, it was formed thicker than Reference Example 1.
Similarly, in Examples 15 to 20 in which the pretreatment was combined with the post-treatment with the activator, the copper film was deposited uniformly on the entire substrate and formed thicker than the reference example 1.
Next, in Examples 21 to 23 in which both the adsorption promotion treatment and the post-treatment steps were combined before and after the pretreatment, the copper film was naturally deposited uniformly on the entire substrate and formed thicker than the reference example 1.
Thus, when the adsorption promotion treatment and / or the post-treatment are combined in combination before and after the pre-treatment, the pre-treatment and the electroless copper plating treatment alone are performed without these treatments (that is, the reference example 1). It was confirmed that the deposition rate of the film could be increased and the film thickness of the resulting copper film increased.

(2) Therefore, first, when Examples 1 to 14 combined with the adsorption promotion treatment are viewed in detail, Examples 1 to 7 are examples using various surfactants as the adsorption accelerator. It can be seen that the same film increasing effect was obtained regardless of the type. In Examples 8 to 9 using a reducing agent as an adsorption accelerator, it was possible to confirm a temporary film increasing effect as compared with Reference Example 1. In Examples 10 to 14 in which a predetermined nitrogen-containing compound and phthalocyanine were used as the adsorption accelerator, a film thickening effect similar to that in the surfactant use example could be confirmed.
As a result, if a compound that appears to have different characteristics, such as a condensed heterocyclic or thiourea-based nitrogen-containing compound, phthalocyanine, reducing agent, or surfactant, is brought into contact with the substrate prior to pretreatment, a common adsorption promotion is achieved. It was confirmed that there was an effect. For example, a condensed heterocyclic or thiourea-based predetermined nitrogen-containing compound attached to a substrate is coordinated to copper nanoparticles used in the next step due to a loan pair of a plurality of nitrogen atoms possessed by each molecule. Thus, it can be expected that the copper nanoparticles are promoted to be adsorbed on the substrate.
In view of the film thickness shown in Table A above, among the condensed heterocyclic nitrogen-containing compounds, thiourea-based nitrogen-containing compounds, or phthalocyanines, the condensed heterocyclic nitrogen-containing compounds have a relatively excellent film increasing effect. I can see that.
Next, in Examples 15 to 20 in which post-treatments were combined, it was shown that the use of a reducing agent was superior to the use of an acid as an activator, and that the film-forming effect was superior, and dimethylamine borane or formaldehyde was used as the reducing agent. When used, relatively good results were obtained. Therefore, it was confirmed that the compounds that seem to have different actions of acid and reducing agent have a common activating action.
Further, in Examples 21 to 23 in which both the adsorption promotion treatment and the post-treatment were combined before and after the pretreatment, it was naturally excellent in the film increasing effect, and in particular, the adsorption promotion treatment with the condensed heterocyclic nitrogen-containing compound and the reduction. It is presumed that a relatively better film thickening effect can be obtained by combining post-treatment with an agent.
In addition, what should be noted in the above-mentioned embodiment is that the reducing agent has both the effects of promoting adsorption and activation.

Claims (4)

(A) Nonionic surfactant, anionic surfactant, cationic surfactant, amphoteric surfactant, thiazole, benzothiazole, methylbenzothiazole, mercaptobenzothiazole, triazole, tolyltriazole, benzotriazole, methylbenzotriazole , Imitazole, 2-undecylimidazole, 2-heptadecylimidazole, benzimidazole, guanidines, thioureas, phthalocyanines, formaldehyde, amineboranes, hypophosphorous acids, ascorbic acid, glyoxalic acid, formic acid An adsorption promoting step of immersing the non-conductive substrate in the liquid containing at least one kind of the adsorption promoting agent,
(B) Copper nanoparticles having an average particle size of 1 to 250 nm are added to a solvent in a solvent by a dispersant selected from a high molecular surfactant, a low molecular surfactant, an inorganic dispersant consisting of tripolyphosphoric acid and a salt thereof. Prepare a pretreatment liquid by dispersing at a content of wt%, immerse the non-conductive substrate that has been subjected to adsorption promotion treatment in the pretreatment liquid, and adsorb the copper nanoparticles contained in the pretreatment liquid on the substrate surface A pre-processing step of
(D) comprising an electroless plating step of forming a copper film on the pretreated substrate using an electroless copper plating solution ,
The electroless copper plating method, wherein the non-conductive substrate is a resin substrate or a glass substrate . (B) Copper nanoparticles having an average particle size of 1 to 250 nm are added to a solvent in a solvent by a dispersant selected from a high molecular surfactant, a low molecular surfactant, an inorganic dispersant consisting of tripolyphosphoric acid and a salt thereof. A pretreatment step of preparing a pretreatment liquid by dispersing at a content of wt%, immersing the non-conductive substrate in the pretreatment liquid, and adsorbing copper nanoparticles contained in the pretreatment liquid on the substrate surface; ,
(C) Containing at least one activator selected from the group consisting of hydrochloric acid, sulfuric acid, carboxylic acid, sulfonic acid, formaldehyde, amine boranes, borohydride compounds, hypophosphorous acids, ascorbic acid, glyoxalic acid, formic acid A post-treatment step of immersing the non-conductive substrate pre-treated in the liquid;
(D) comprising an electroless plating step of forming a copper film on the post-treated substrate using an electroless copper plating solution ,
The electroless copper plating method, wherein the non-conductive substrate is a resin substrate or a glass substrate . (A) Nonionic surfactant, anionic surfactant, cationic surfactant, amphoteric surfactant, thiazole, benzothiazole, methylbenzothiazole, mercaptobenzothiazole, triazole, tolyltriazole, benzotriazole, methylbenzotriazole , Imitazole, 2-undecylimidazole, 2-heptadecylimidazole, benzimidazole, guanidines, thioureas, phthalocyanines, formaldehyde, amineboranes, hypophosphorous acids, ascorbic acid, glyoxalic acid, formic acid An adsorption promoting step of immersing the non-conductive substrate in a liquid containing at least one kind of adsorption promoter
(B) Copper nanoparticles having an average particle size of 1 to 250 nm are added to a solvent in a solvent by a dispersant selected from a high molecular surfactant, a low molecular surfactant, an inorganic dispersant consisting of tripolyphosphoric acid and a salt thereof. Prepare a pretreatment liquid by dispersing at a content of wt%, immerse the non-conductive substrate that has been subjected to adsorption promotion treatment in the pretreatment liquid, and adsorb the copper nanoparticles contained in the pretreatment liquid on the substrate surface A pre-processing step of
(C) Containing at least one activator selected from the group consisting of hydrochloric acid, sulfuric acid, carboxylic acid, sulfonic acid, formaldehyde, amine boranes, borohydride compounds, hypophosphorous acids, ascorbic acid, glyoxalic acid, formic acid A post-treatment step of immersing the non-conductive substrate pre-treated in the liquid;
(D) comprising an electroless plating step of forming a copper film on the post-treated substrate using an electroless copper plating solution ,
The electroless copper plating method, wherein the non-conductive substrate is a resin substrate or a glass substrate . The content of the dispersant with respect to the copper nanoparticles is 3 to 70% by weight,
The solvent is an organic solvent having a boiling point of 250 ° C or lower and a flash point of 10 ° C or higher at normal pressure, or water, and the pH of the pretreatment liquid is 3.0 to 10.0. The electroless copper plating method according to any one of the above.