TWI684673B - Copper colloidal catalyst solution for electroless copper plating and electroless copper plating method - Google Patents

Abstract

The present invention provides a copper colloidal catalyst solution for electroless copper plating. After pretreatment for promoting absorption by immersing a non-conductive substrate into a liquid containing surfactant, the copper colloidal catalyst solution for electroless copper plating comprising (A) soluble copper salt, (B) reducing agent, (C) colloidal stabilizer and (D) specific carbohydrate such as glucose, maltose, xylitol and sorbitol, is used to apply the non-conductive substrate with catalyst and then the electroless copper plating is conducted so that the catalyst solution is stable over time. In addition, after pretreatment to enhance the catalyst activity, and catalyst application with catalyst solution and electroless plating, an excellent and uniform copper film can be obtained.

Description

Copper colloidal catalytic solution for electroless copper plating and electroless copper plating method

The present invention relates to a copper colloidal catalytic solution applied as a catalyst for pretreatment when performing electroless copper plating on a non-conductive substrate, an electroless copper plating method using the catalytic solution, and a non-copper film formed by this method. The conductive substrate provides a technical solution that can significantly improve the stability of the copper catalytic solution over time and give the copper coating an excellent appearance.

For conductive substrates represented by copper or copper alloy substrates, or glass-epoxy resins, glass-polyimide resins, epoxy resins, polyimide resins, polycarbonate resins, ABS resins, A resin substrate such as PET resin is representative. Electroless copper plating is performed on non-conductive substrates such as glass substrates and ceramic substrates. The usual method is: first, noble metals such as palladium, silver, and platinum are adsorbed on the substrate as a catalyst core, and then With the use of the catalyst core, a copper film is deposited on the substrate using an electroless copper plating solution.

On the other hand, there is also a catalyst-imparting method that uses low-cost copper, nickel, cobalt, and other specific metals without using a precious metal catalyst. The basic principle of this method is: in the catalytic solution of the specific metal, the soluble metal is treated with a reducing agent The salt generates colloidal particles of the metal and uses it as a catalyst core.

Among them, the prior art of copper colloidal catalytic solution is listed as follows: Patent Document 1 discloses the addition of soluble copper salt, dispersant (gelatin, nonionic surfactant), and complexing agent (dicarboxylic acid, oxycarboxylic acid) Etc.), after reducing treatment with a reducing agent (sodium borohydride, dimethylamine borane, etc.), the stabilizer (sodium hypophosphite, di Methylamine borane, etc.) is made into a fine copper catalytic solution for electroless copper plating.

Patent Document 2 discloses that an electroless plating catalyst composed of a copper salt (copper amine complex in Preparation Example 2), an anionic surfactant, and a reducing agent is applied to an object to be plated, and after electroless copper plating, electroplating is performed. Copper (requests 1~2, paragraph 42).

Patent Document 3 discloses that after a catalyst is applied to a substrate using a copper (I) colloidal catalyst solution, the substrate is immersed in a solution containing a copper salt, a reducing agent, and a complexing agent, and copper is directly plated on the substrate.

Patent Document 4 discloses that a regulator containing a surfactant (cationic, amphoteric, nonionic, etc., paragraph 56) is used to pretreat the object to be plated, and then a monovalent copper salt, hypophosphite and chloride ion are used. Or an electroless copper plating method in which a catalyst solution containing a reducing agent (amine boranes, boron hydrides, etc.) is subjected to catalyst treatment (request items 8 to 9, paragraph 70).

Patent Document 4 also describes that if a cationic surfactant is used in particular in the above-mentioned regulator, the hydrophilic group of the surfactant adsorbed on the object is negatively charged, and the above-mentioned monovalent copper ion becomes easily adsorbed (paragraph 58).

Patent Document 5 describes the treatment of a non-conductive substrate using a dispersion liquid containing an activator of a noble metal/metal-colloid (for example, a palladium/tin colloid solution), followed by conduction with a copper salt solution, a complexing agent, and a reducing agent After the body solution is contacted, the methods of electroless plating and electroplating are carried out (paragraphs 1, 13, 24, 29, 65, Table 1).

The basic principle of the above-mentioned aqueous catalytic solution is to use a reducing agent to treat soluble metal salts to generate fine metal particles, but in fact, including the catalytic solutions of the above Patent Documents 1 to 5, the catalytic solutions of this principle usually exist in terms of stability over time. The problem is that it is not easy to maintain the continuity of catalyst giving and electroless plating operations smoothly for a long time.

If the stability over time is reduced, even if the catalyst is applied and electroless copper plating is performed, the coating may occur, or there may be a problem that the coating film is not partially deposited, the coating film is streaked, or the uniformity is poor.

For example, a copper coating that is chemically plated after being treated with a catalytic solution at the beginning of the bath At this time, the lower the stability over time when the bath is built, the worse the appearance of the coating. However, it is also necessary to consider the stability over time in units of several months after the bath is built. In other words, even if the coating treated with the catalytic solution in the initial stage of the bath is in good appearance, the coating appearance or the above-mentioned coating defects or streaks may not occur if the catalytic solution is treated with the catalytic solution after a few months from the establishment of the bath. Less, so the stability of the catalytic solution over time is important.

Therefore, the applicant proposed in Japanese Patent Application No. 2014-022271 (hereinafter referred to as the first application invention) to add colloidal stabilizers such as hydroxycarboxylic acids and aminocarboxylic acids that stabilize copper salts to a copper catalytic solution, while adjusting A copper colloidal catalytic solution in which the mixing ratio of the copper salt and the stabilizer is zero or the content of the surfactant is suppressed to a very small amount or less, thereby improving the temporal stability of the catalytic solution.

Considering the improvement of the appearance of the copper film obtained by electroless plating or the reduction of the processing cost, it is desired to further improve the stability of the catalytic solution over time.

Therefore, focusing on whether the addition of saccharides to the catalytic solution will affect the stability of the catalytic solution over time, and extracting patent documents containing the technical content of using saccharides when performing electroless copper plating after the catalyst is given are as follows.

(1) Patent Literature 6

A method of reducing a metal salt on a non-conductive substrate, performing a catalyst application process, and then performing an electroless copper plating process (request item 1, paragraph 1). The composition for applying the catalyst application includes glucose, galactose, and maltose ( reducing sugars such as maltose, fructose, and xylose (request items 1, 10, paragraphs 1, 24). In addition, the above composition may further contain buffering agents such as citric acid, tartaric acid, and malic acid (paragraph 19).

Similar existing documents include Japanese Patent Laid-Open No. 2012-127002 (Rohm & Haas).

(2) Patent Literature 7

A method of reducing a metal salt (copper salt, etc.) on a non-conductive substrate to provide a catalyst-imparting treatment, and then performing an electroless copper plating treatment (requests 1, 3, paragraph 29, table 1). The original agent may include glucose (paragraph 25). In addition, by dissolving carboxylic acids such as tartaric acid, citric acid, and succinic acid, sugars such as sucrose, fructose, and the like in the catalyst solution, the amount of adhesion of the catalyst metal to the substrate surface can be increased (paragraph 31).

(3) Patent Literature 8

A method of performing a catalyst-imparting treatment using a silver colloidal catalytic solution (pretreatment liquid) instead of a copper catalytic solution, and then performing electroless copper plating (request items 1, 35).

In addition to hydroxycarboxylic acids such as citric acid, tartaric acid, lactic acid, and malic acid (claims 1 and 3), it is also possible to add cellulose and its derivatives, monosaccharides, polysaccharides and their derivatives to the catalytic solution Colloidal dispersant (paragraph 46).

Monosaccharides, polysaccharides and their derivatives are sucrose, mannitol, sorbitol, glycerin, dextrin, etc. (paragraph 50).

(4) Patent Literature 9

A non-conductive substrate made of a resin molded body is etched to contact a colloidal solution containing a precious metal compound (gold, silver, etc.) and a stannous salt, and then contacted with an aqueous solution of a palladium compound for catalyst addition treatment, and then electroless plating Copper processing method (request items 1~2).

Reducing sugars such as glucose, sorbit, cellulose, sucrose, mannite, and gluconolactone may be added to the electroless copper plating solution instead of the above-mentioned catalytic solution (paragraph 73).

(5) Patent Literature 10

Etching is performed on non-conductive substrates such as resin, ceramics, glass, etc., and tin salts (stannous chloride, etc.) are attached for induction treatment, and immersed in a silver nitrate solution to replace silver on tin to form a tin-silver composite, A method of immersing in a reducing solution for activation and then performing electroless copper plating (requests 1 to 6, paragraphs 10 and 22). Glucose can be used in the reducing solution.

Existing technical literature:

[Patent Literature]

Patent Document 1: Japanese Patent Laid-Open No. H02-093076, Patent Document 2: Japanese Patent Laid-Open No. H10-229280, Patent Document 3: Japanese Patent Laid-Open No. H07-197266, Patent Document 4: Japanese Patent Laid-Open No. 2011-225929, Patent Document 5: Japanese Patent Laid-Open No. 2013-522476, Patent Document 6: Japanese Patent Laid-Open No. 2012-130910, Patent Document 7: Japanese Patent Laid-Open No. 2003-313670, Patent Document 8: Japanese Patent Laid-Open No. 2004-190042, Patent Document 9: Japanese Patent Laid-Open No. 2006-299366, Patent Document 10: Japanese Patent Laid-Open No. 2005-146330.

In the above Patent Documents 6 to 10, sugars such as glucose, fructose, maltose, and cellulose, or sugar alcohols such as mannitol and sorbitol are used as the catalytic solution of the pretreatment agent.

However, in Patent Document 9, sugars and sugar alcohols are used for the electroless copper plating solution instead of the catalytic solution.

The technical problem to be solved by the present invention is to expand its characteristic composition on the basis of the above-mentioned first application invention and further improve the stability of the copper colloidal catalytic solution over time.

Based on the above Patent Documents 6 to 10, the inventors conducted an in-depth study on the relationship between the copper colloidal catalytic solution added with carbohydrates containing sugars and sugar alcohols and their stability over time, and found that if a specific carbohydrate is selected When the compound is added to the copper colloidal catalytic solution, it can effectively improve the temporal stability of the catalytic solution compared to the case without carbohydrates. In addition, it is also found that the above-mentioned temporal stability will not be affected even if a carbohydrate other than a specific carbohydrate is added. Increasing or conversely decreasing will complete the present invention.

That is, the present invention 1 is a copper colloidal catalytic solution for electroless copper plating, which is used for A copper colloidal catalytic solution provided by a catalyst in contact with a non-conductive substrate subjected to electroless copper plating, containing: (A) soluble copper salt; (B) reducing agent; (C) selected from monocarboxylic acids, hydroxycarboxylic acids, and aminocarboxylic acids At least one of colloidal stabilizers in acids and polycarboxylic acids; and (D) selected from glucose, fructose, lactose, maltol, isomaltulose, xylose, sorbitol, xylitol, At least one of carbohydrates in mannitol, maltitol, erythritol, reduced starch syrup, lactitol, reduced palatinose, and gluconolactone.

The present invention 2 is, in the above-mentioned present invention 1, the content ratio of the soluble salt (A) and the colloid stabilizer (C) is a molar ratio A: C=1:0.03~1:35 copper colloidal catalytic solution for electroless copper plating .

The present invention 3 is the above-mentioned present invention 1 or 2 further containing a synthetic water-soluble material selected from polyethylene glycol, polypropylene glycol, polyvinylpyrrolidone, polyvinyl alcohol, polypropylene amide, and polyethyleneimine Copper colloidal catalytic solution for electroless copper plating of at least one of the polymers.

The present invention 4 is that in any of the above-mentioned present inventions 1 to 3, the reducing agent (B) is selected from the group consisting of boron hydride compounds, amine boranes, hypophosphorous acids, aldehydes, ascorbic acids, hydrazines, and polyphenols Copper colloidal catalytic solution for electroless copper plating of at least one of the types, multi-component naphthols, phenolsulfonic acids, naphtholsulfonic acids, and sulfinic acids.

The invention 5 is that in any one of the inventions 1 to 4 above, the monocarboxylic acids in the colloidal stabilizer (C) are selected from formic acid, acetic acid, propionic acid, butyric acid, valeric acid, hexanoic acid, caprylic acid, At least one of capric acid, lauric acid, myristic acid, palmitic acid, stearic acid, and salts thereof; hydroxycarboxylic acids are selected from citric acid, tartaric acid, malic acid, gluconic acid, glucoheptonic acid, and ethanol At least one of acid, lactic acid, trioxybutyric acid, ascorbic acid, isocitric acid, hydroxymalonic acid, glyceric acid, hydroxybutyric acid, leucine, citracallic acid, and salts thereof; amino The carboxylic acids are selected from hydroxyethylethylenediaminetriacetic acid, diethylenetriaminepentaacetic acid, triethylenetetraminehexaacetic acid, ethylenediaminetetraacetic acid, ethylenediaminetetrapropionic acid, ammoniatriacetic acid, imino Diacetic acid, hydroxyethyliminodiacetic acid, iminodipropionic acid, 1,3-propanediamine tetraacetic acid, 1,3-diamino-2-hydroxypropanetetraacetic acid ( 1,3-diamino-2-hydroxypropane tetraacetic acid), glycol ether diamine tetraacetic acid, m-benzene Diamine tetraacetic acid, 1,2-cyclohexanediamine-N,N,N',N'-tetraacetic acid, diaminopropionic acid, glutamic acid, dicarboxy methyl glutamate, bird At least one of amino acid, cysteine, N,N-bis(2-hydroxyethyl) glutamic acid, (S,S)-ethylenediamine succinic acid, and their salts; polycarboxylic acids ( C) is at least one salt selected from the group consisting of succinic acid, glutaric acid, malonic acid, adipic acid, oxalic acid, maleic acid, citraconic acid, itaconic acid, mesaconic acid, and the like Copper colloidal catalytic solution for electroless copper plating.

The present invention 6 is an electroless copper plating method, which includes: (a) an adsorption promotion step (pretreatment step), immersing a non-conductive substrate in a liquid containing an adsorption promoter selected from a non-ionic surface At least one of an active agent, a cationic surfactant, an anionic surfactant, and an amphoteric surfactant; (b) a catalyst-imparting step, a non-conductive substrate is immersed in any of the above 1 to 5 of the present invention In the copper colloidal catalytic solution, the copper colloidal particles are adsorbed on the surface of the substrate; and (c) an electroless plating step, using an electroless copper plating solution to form a copper coating on the substrate subjected to the adsorption treatment.

The present invention 7 is an electroless copper plating method in which the adsorption accelerator in step (a) is a cationic surfactant and/or amphoteric surfactant in the above-mentioned present invention 6.

The present invention 8 is a non-conductive substrate in which a copper coating is formed by the above-mentioned electroless copper plating method of the present invention 6 or 7.

In the above-mentioned first application invention, it is proposed to immerse the non-conductive substrate in a copper catalytic solution containing a copper salt, a reducing agent, and a colloidal stabilizer, so as to use its catalytic activity to precipitate a copper film with a good appearance in the next step of electroless copper plating.

In the present invention, by further adding specific carbohydrates to the essential components of the copper catalytic solution of the first application of the invention, the temporal stability of the catalytic solution can be significantly improved, and a copper coating excellent in appearance can be obtained by electroless plating.

In particular, the colloidal catalytic solution is stable even after a few months from the establishment of the bath. Therefore, a coating with excellent appearance can be obtained, the maintenance of the catalytic solution can be reduced, and the electroless copper plating can be improved. Productivity.

As a pretreatment for electroless copper plating, there has conventionally been catalyst provision using tin-palladium or the like, but no precious metals are used in the present invention, so the cost of manufacturing a substrate can be reduced without removing palladium applied to the substrate.

In addition, if the adsorption promoting treatment is performed with a surfactant before the catalyst is applied to the non-conductive substrate, the effect of the copper colloidal catalyst can be improved. Especially if treated with a cationic active agent, the effect of the copper colloidal catalyst is significantly improved.

The first aspect of the present invention is a copper colloidal catalytic solution for electroless copper plating, which is a copper colloidal catalytic solution for contacting with a non-conductive substrate to give a catalyst, and contains (A) a soluble copper salt, (B) a reducing agent and ( C) A colloidal stabilizer, and also containing (D) a specific carbohydrate; the second aspect is an electroless copper plating method using the catalytic solution of the first aspect above, which is performed on a non-conductive substrate with a liquid containing a surfactant in advance After the adsorption promotion treatment, the catalyst solution is applied using the above-mentioned catalytic solution and then electroless copper plating is performed. The third aspect is a non-conductive substrate in which a copper film is formed by the electroless copper plating method of the second aspect.

The above-mentioned non-conductive substrate refers to resin substrates such as glass-epoxy resin, glass-polyimide resin, epoxy resin, polyimide resin, polycarbonate resin, ABS resin, PET resin, etc., including glass Substrates, ceramic substrates, etc.

The essential components of the above copper colloidal catalytic solution of the present invention 1 are (A) soluble copper salt, (B) reducing agent, (C) colloidal stabilizer, and (D) specific carbohydrate.

Any soluble salt can be used as long as the above-mentioned soluble salt (A) is a soluble salt that generates monovalent or divalent copper ions in an aqueous solution, and a hardly soluble salt is not excluded. Specifically, copper sulfate, copper oxide, copper chloride, copper pyrophosphate, copper carbonate; or copper acetate, copper oxalate, copper citrate and other carboxylic acid copper salts; or copper methanesulfonate and hydroxyl group Copper ethanesulfonate Copper salts of organic sulfonic acids and the like are preferably copper sulfate, copper citrate, and copper methanesulfonate.

Examples of the reducing agent (B) include borohydride compounds, amine boranes, hypophosphorous acids, aldehydes, ascorbic acids, hydrazines, polyphenols, polynaphthols, phenolsulfonic acids, and naphtholsulfonic acids. , Sulfinic acid, etc. Aldehydes are formaldehyde, glyoxylic acid or its salts, and polyphenols are catechol, hydroquinone, resorcinol, pyrogallol, resorcinol, gallic acid, etc. The acids are phenolsulfonic acid, cresolsulfonic acid or their salts, and the like.

The colloidal stabilizer (C) is a compound that forms a copper complex in the plating bath and functions to ensure the stability of the catalytic solution over time.

The colloidal stabilizer (C) is selected from monocarboxylic acids, hydroxycarboxylic acids, aminocarboxylic acids, and polycarboxylic acids.

Examples of the monocarboxylic acids include formic acid, acetic acid, propionic acid, butyric acid, valeric acid, caproic acid, caprylic acid, capric acid, lauric acid, myristic acid, palmitic acid, stearic acid, and salts thereof.

Examples of the aforementioned hydroxycarboxylic acids include citric acid, tartaric acid, malic acid, gluconic acid, glucoheptonic acid, glycolic acid, lactic acid, trihydroxybutyric acid, ascorbic acid, isocitric acid, hydroxymalonic acid, glyceric acid, and hydroxy Butyric acid, leucine, citracallic acid, and their salts, etc.

Examples of the aminocarboxylic acids include ethylenediaminetetraacetic acid (EDTA), hydroxyethylethylenediaminetriacetic acid (HEDTA), diethylenetriaminepentaacetic acid (DTPA), and triethylenetetraminehexaacetic acid ( TTHA), ethylenediaminetetrapropionic acid, aminotriacetic acid (NTA), iminodiacetic acid (IDA), iminodipropionic acid (IDP), hydroxyethyliminodiacetic acid, 1,3-propanediamine Acetic acid, 1,3-diamino-2-hydroxypropanetetraacetic acid, glycol ether diaminetetraacetic acid, m-phenylenediaminetetraacetic acid, 1,2-cyclohexanediamine-N,N,N',N' -Tetraacetic acid, diaminopropionic acid, glutamic acid, dicarboxymethyl glutamic acid, ornithine, cysteine, N,N-bis(2-hydroxyethyl) glutamic acid, (S,S )-Ethylenediamine succinic acid and its salts.

Examples of the above polycarboxylic acids include succinic acid, glutaric acid, malonic acid, adipic acid, oxalic acid, maleic acid, citraconic acid, itaconic acid, mesaconic acid, and salts thereof, etc. .

The colloidal catalytic solution of the present invention has the option of adding specific carbohydrates (D) feature.

The above carbohydrates (D) are mainly added to improve the stability of the colloidal catalytic solution over time, and are selected from glucose, fructose, lactose, maltose, and isomaltulose ( Palatinose), xylose, sorbitol, xylitol, mannitol, maltitol, erythritol, reduced starch syrup, lactitol, reduced isomaltulose, gluconolactone.

The above glucose, fructose, xylose, etc. are monosaccharides, gluconolactone is a derivative of monosaccharides, lactose, maltose, etc. are disaccharides, sorbitol, xylitol, mannitol, etc. are sugar alcohols, and the carbohydrate of the present invention The concept of compounds includes the aforementioned sugars and their derivatives, sugar alcohols.

The reduced starch syrup refers to a starch syrup in which the aldehyde groups of specific sugars such as glucose and maltose are reduced to hydroxyl groups. In addition, as the above-mentioned carbohydrate (D), oligomers in which specific monosaccharides such as glucose, fructose, and xylose are polymerized with three or more glycosidic bonds are also effective.

On the other hand, the above carbohydrates are selected from specific ingredients, so starch, dextrin, etc. are excluded.

Preferred carbohydrates include glucose, fructose, lactose, maltose, sorbitol, xylitol, mannitol, and gluconolactone, and sugar alcohols are generally preferred.

The copper colloidal catalytic solution of the present invention is an aqueous system, so the liquid solvent is limited to water and/or hydrophilic alcohols, excluding organic solvents (including lipophilic alcohols) to be used alone.

In addition, regarding this catalytic solution, since the catalyst activity tends to decrease near neutrality, it is preferable that the pH value of the catalytic solution is on the acidic side or the basic side other than the neutral region, specifically pH 1 to 6 and 8 to 12 are more suitable It is preferably pH 2 to 5 and 8 to 11. If the pH value is adjusted to pH 2 to 5 and 8 to 11, the copper colloidal particles are easily stabilized.

In the copper colloidal catalytic solution, the above-mentioned soluble copper salt (A) can be used alone or in combination, and its content is 0.005 to 3 mol/L, preferably 0.05 to 2 mol/L, and more preferably 0.04 to 1.2 mol /L.

The reducing agent (B) can be used alone or in combination, and its content is 0.005 to 4 mol/L, preferably 0.02 to 3 mol/L, and more preferably 0.03 to 2.2 mol/L. If the content of the reducing agent is less than the appropriate amount, the reduction effect of the copper salt is reduced, whereas if it is too much, the homogeneity of the copper film deposited by electroless plating may be reduced.

The colloidal stabilizer (C) can be used alone or in combination, and its content is 0.005 to 4 mol/L, preferably 0.01 to 2 mol/L, and more preferably 0.05 to 1.6 mol/L.

The above carbohydrates (D) can be used alone or in combination, and the content thereof is 0.001 to 4 mol/L, preferably 0.01 to 3 mol/L, and more preferably 0.05 to 2.2 mol/L.

In the copper colloidal catalytic solution, the molar ratio of the above (A) to (C) is A:C=1:0.03~1:35, preferably A:C=1:0.5~1:24. If the relative content of the colloidal stabilizer (C) is too small, the temporal stability of the catalytic solution is reduced, and it also becomes the main cause of precipitation defects of the copper coating obtained by electroless plating. Conversely, if the content of the colloidal stabilizer (C) is too large, the temporal stability of the catalytic solution will be impaired, and the quality of the resulting copper coating will be degraded (refer to the test examples described later).

In the copper colloidal catalytic solution, the molar ratio of the above (A) to (B) is A:B=1:0.01~1:6, preferably A:B=1:0.05~1:4, more preferably A: B=1:0.07~1:2.

In the copper colloidal catalytic solution, the molar ratio of (A) to (D) above is A: D=1:0.01~1:40, preferably A:D=1:0.1~1:25, more preferably A: D=1:1~1:15. If the relative content of carbohydrates (D) is too large, the colloidal catalytic solution will be excessively stabilized and the catalyst activity will be lost, which may impart to the catalyst core of the non-conductive substrate, which may hinder the formation of a good-looking coating.

When preparing the catalytic solution, since the electrons are smoothly supplied from the reducing agent to the copper ions, basically it takes time to slowly drop the reducing agent solution into the solution containing the soluble copper salt (and colloidal stabilizer) for preparation. For example, a reducing agent solution at 5 to 50°C (preferably 10 to 40°C) is dropped into the copper salt solution, and stirred for 20 to 1200 minutes (preferably 30 to 300 minutes) to prepare a catalytic solution. It should be noted that in the preparation of the catalytic solution, it is not excluded to drop the soluble copper salt solution into Reductant solution.

In the catalytic solution of the present invention, the copper colloidal particles generated from the soluble copper salt by the action of the reducing agent are fine particles having an average average particle diameter of 1 to 250 nm, preferably 1 to 120 nm, and more preferably 1 to 100 nm.

If the average particle size of the copper colloidal particles is 250 nm or less, it can be inferred that when the non-conductive substrate is immersed in the catalytic solution, the colloidal particles enter the concave portions of the fine uneven surface of the substrate, and the anchoring effect such as dense adsorption or hanging, Promote the application of copper colloid cores to the substrate surface. Conversely, if the average particle size is greater than 250 nm, not only will it be difficult to obtain stable copper colloids due to aggregation, precipitation, or separation, but also the anchoring effect will be unsatisfactory. Therefore, copper colloid particles can only be locally applied to the surface of the substrate, or may appear Give bad.

The copper colloidal catalytic solution of the present invention 1 may contain a surfactant. However, since the catalyst activity may be reduced, the content of the surfactant is preferably suppressed to 950 mg/L or less.

The above-mentioned surfactants refer to nonionic, amphoteric, cationic, or anionic surfactants, and amphoteric, cationic, anionic, or low-molecular nonionic surfactants are not particularly preferred.

Examples of the above nonionic surfactants include C1-C20 fatty alcohols, phenols, naphthols, bisphenols, (poly)C1-C25 alkylphenols, (poly)arylalkylphenols, and C1- Addition condensation of C25 alkylnaphthol, C1~C25 alkoxylated phosphoric acid (salt), sorbitan ester, polyalkylene glycol, C1~C22 fatty amine, C1~C22 fatty amide, etc. 2~300 Mole ethylene oxide (EO) and/or propylene oxide (PO) compounds, or C1-C25 alkoxylated phosphoric acid (salt), etc.

Examples of the cationic surfactants include quaternary ammonium salts and pyridine salts, and specific examples thereof include dodecyl trimethyl ammonium salt, octadecyl trimethyl ammonium salt, and dodecyl group. Dimethyl ethyl ammonium salt, octadecyl dimethyl ethyl ammonium salt, dimethyl benzyl dodecyl ammonium salt, hexadecyl dimethyl benzyl ammonium salt, octadecyl dimethyl Benzyl ammonium salt, trimethyl benzyl ammonium salt, triethyl benzyl ammonium salt, dimethyl diphenyl ammonium salt, benzyl dimethyl phenyl ammonium salt, cetyl pyridinium salt, twelve Alkylpyridinium salt, dodecylpyridinium salt, stearylamine acetate, laurylamine Acetate, octadecylamine acetate, etc.

Examples of the anionic surfactant include alkyl sulfate, polyoxyethylene alkyl ether sulfate, polyoxyethylene alkyl phenyl ether sulfate, alkylbenzene sulfonate, [(mono, di, tri ) Alkyl] naphthalene sulfonate, etc.

Examples of the amphoteric surfactants include carboxybetaine, imidazoline betaine, sulfobetaine, and aminocarboxylic acid. In addition, sulfated or sulfonated adducts of condensation products of ethylene oxide and/or propylene oxide with alkylamines or diamines can also be used.

In order to improve the dispersibility of colloidal particles, a uniform and non-marking coating is obtained during electroless copper plating. The copper colloidal catalytic solution of the present invention may contain a synthetic water-soluble polymer.

If this synthetic water-soluble polymer is contained in the catalytic solution, the dispersibility of the colloidal particles is improved, which contributes to the precipitation of a copper film having excellent uniformity and no streaks during electroless copper plating.

The above-mentioned synthetic water-soluble polymer refers to the exclusion of water-soluble polymers of natural origin such as gelatin and starch, but does not exclude the semi-synthetic cellulose derivatives such as carboxymethyl cellulose (CMC) and methyl cellulose (MC) .

The catalytic solution of the present invention 3 contains synthetic water-soluble polymers. In the relationship with the above-mentioned surfactants, the components belonging to them may be partially repeated, but in the present invention, the two are different concepts.

In the catalytic solution of the present invention 3, it is not necessary to include components other than the water-soluble polymer. For example, whether or not a surfactant is included, that is, whether or not the surfactant is included may be sufficient.

As shown in the present invention 3, examples of the synthetic water-soluble polymer include polyethylene glycol (PEG), polypropylene glycol (PPG), polyvinylpyrrolidone (PVP), polyvinyl alcohol (PVA), and polypropylene amide. Amine (PAM), polyethyleneimine (PEI), polyacrylate, etc., particularly preferably high molecular weight PEG, PVP, PVA, etc.

Synthetic water-soluble polymers can be used alone or in combination. The content of the liquid is 0.05 to 100 g/L, preferably 0.5 to 50 g/L, and more preferably 1.0 to 30 g/L.

The present invention 6 is an electroless plating method using the above copper colloidal catalytic solution, which is sequentially combined by the following three steps: (a) an adsorption promoting step, (b) a catalyst providing step, and (c) an electroless copper plating step.

The above-mentioned adsorption promotion step (a) can be regarded as a pretreatment (preliminary treatment) step given by the catalyst of step (b), which is a step of immersing the non-conductive substrate in the liquid containing the adsorption promoter, and the adsorption promoter is selected from At least one of an ionic surfactant, a cationic surfactant, an anionic surfactant, and an amphoteric surfactant. By contacting the substrate with a liquid containing a surfactant, the wettability of the substrate surface can be improved, the catalyst activity can be enhanced, and the adsorption of copper colloidal particles in the next step can be promoted.

In the adsorption promotion step, the non-conductive substrate needs to be in contact with the liquid containing the surfactant, so it is basically immersed in the liquid, but the liquid containing the surfactant can also be sprayed on the substrate or coated on the substrate with bristles First class.

As shown in the present invention 7, from the viewpoint of promoting adsorption, a positively charged cationic or amphoteric surfactant is suitable, and a cationic surfactant is more particularly preferred. In addition, if a small amount of nonionic surfactant is used in combination with the cationic surfactant, the effect of promoting the adsorption further increases.

In the catalytic solution of the present invention, the zeta potential of the copper colloidal particles generated by the reducing agent acting on the soluble copper salt is a negative value. Therefore, for example, if a non-conductive substrate is subjected to contact treatment with a cationic surfactant, the substrate is likely to carry With positive charge, the adsorption efficiency of the copper colloidal particles to the substrate increases in the next step.

Specific examples of the surfactant are as described in the description of the surfactant described as the object of excluding or suppressing the object in the catalytic solution of the present invention 1 described above.

The content of the surfactant is 0.05 to 100 g/L, preferably 0.5 to 50 g/L. Preferably, the temperature of the liquid containing the surfactant is about 15 to 70° C., and the immersion time is about 0.5 to 20 minutes.

After the non-conductive substrate after the adsorption promotion treatment is washed with pure water, dry or not After drying, proceed to the next step of giving catalyst (b).

In the catalyst application step, the non-conductive substrate is immersed in the above-mentioned copper colloidal catalytic solution to adsorb the copper colloidal particles on the substrate surface.

The liquid temperature of the catalytic solution is 5 to 70°C, preferably 15 to 60°C, the immersion time is 0.1 to 20 minutes, preferably 0.2 to 10 minutes, and when the immersion treatment is performed, the substrate is placed in a state of being statically placed in the catalytic solution It can be immersed under water, but it can also be stirred or stirred.

In addition, if the pickling treatment step is inserted after the catalyst imparting step (b) and before the next electroless copper plating step (c), the activity of the catalyst activity can be further improved compared to the case without pickling, even The substrate with a complex shape having through holes or through holes can also reliably prevent the adverse effects of copper plating unevenness or wire breakage, and further improve the adhesion of the copper coating.

When pickling, the acid concentration is 10 to 200 g/L, preferably 20 to 100 g/L. For the acid, inorganic acids such as sulfuric acid and hydrochloric acid, organic acids such as organic sulfonic acid, acetic acid, tartaric acid, and citric acid can be used .

The treatment temperature of pickling is 5 to 70°C, preferably 15 to 60°C, and the treatment time is 0.1 to 20 minutes, preferably 0.2 to 10 minutes.

The non-conductive substrate immersed in the catalytic solution is washed with pure water, dried or not dried, and then enters the electroless copper plating step (c).

The electroless copper plating may be processed in the same manner as the prior art, and is not particularly limited. The liquid temperature of the electroless copper plating solution is usually 15 to 70°C, preferably 20 to 60°C.

The stirring of the copper plating liquid may be mechanical stirring such as air stirring, rapid liquid flow stirring, stirring blades and the like.

The present invention 8 is a non-conductive substrate for forming a copper film by the above-mentioned electroless copper plating method, and refers to the above-mentioned substrate for forming a copper film through the adsorption promotion, catalyst application, and electroless plating of the present invention 6.

As described above, the non-conductive substrate refers to a resin substrate such as glass-epoxy resin, glass-polyimide resin, epoxy resin, or polyimide resin, or a glass substrate, ceramic substrate, or the like.

The composition of the electroless copper plating solution is not particularly limited, and a well-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 or a pH adjusting agent or an acid.

Regarding the soluble copper salt, as described above for the copper colloidal catalytic solution.

Regarding the reducing agent contained in the electroless copper plating solution, as shown in the above description of the copper colloidal catalytic solution, represented by formaldehyde (formaldehyde water), including hypophosphorous acid, phosphorous acid, amine borane, boron hydrogen Type, glyoxylic acid, etc., preferably formaldehyde water.

The complexing agent contained in the electroless copper plating solution also includes the parts common to the colloid stabilizer described in the above copper colloidal catalytic solution, specifically: ethylenediaminetetraacetic acid (EDTA), diethylenetriamine Aminocarboxylic acids such as pentaacetic acid (DTPA), triethylenetetraminehexaacetic acid (TTHA), hydroxyethylethylenediaminetriacetic acid (HEDTA), aminotriacetic acid (NTA), and iminodiacetic acid (IDA); Polyamines such as amine, tetramethylenediamine, hexamethylenediamine, diethylenetriamine, tetraethylenepentamine, pentaethylenehexamine, etc.; monoethanolamine, diethanolamine, triethanolamine, etc. Amino alcohols; hydroxycarboxylic acids such as citric acid, tartaric acid, lactic acid, malic acid; thioglycolic acid, glutamic acid, etc.

The electroless copper plating solution may contain organic acids, inorganic acids or salts thereof as the basic components of the liquid.

Examples of the inorganic acid include sulfuric acid, pyrophosphoric acid, and fluoroboric acid. Examples of the organic acid include hydroxycarboxylic acids such as glycolic acid and tartaric acid, and organic sulfonic acids such as methanesulfonic acid and 2-hydroxyethanesulfonic acid.

[Example]

Hereinafter, embodiments of the electroless copper plating method including the preparation of the liquid containing the adsorption accelerator of the present invention, the copper colloidal catalytic solution, and the electroless copper plating solution will be described, and the copper colloidal catalytic solution will be sequentially stabilized over time. Examples of evaluation tests of the properties and appearance of the copper coatings obtained in the above examples are described.

It should be noted that the present invention is not limited to the following examples and test examples, and of course can be arbitrarily modified within the scope of the technical idea of the present invention.

"Examples of Electroless Copper Plating Method"

In the following Examples 1 to 20, Examples 9 to 10 are examples in which the synthetic water-soluble polymer is contained in the catalytic solution, and the other examples are examples without the water-soluble polymer, Examples 2 to 20 This is an example of changing the components and the like based on Example 1 or Example 4.

Example 1 is an example of using citric acid as a colloidal stabilizer, xylitol (sugar alcohol) as a carbohydrate, and sodium borohydride and hypophosphorous acid as a reducing agent in a catalytic solution. Example 2 is based on Example 1 and adjusts the content of xylitol to the lower limit of the above normal range, and Example 3 is an example of adjusting the content of xylitol to the upper limit of the above normal range. Example 4 is an example of using sorbitol (sugar alcohol) as a carbohydrate, and similarly Example 5 is an example of using mannitol (sugar alcohol) as a carbohydrate, and example 6 is using a gluconolactone (derivation of monosaccharides) of a carbohydrate (Example), Example 7 is an example of using glucose (monosaccharides) as carbohydrates, and Example 8 is an example of using maltose (disaccharides) as carbohydrates. Example 9 is an example of using xylitol as a carbohydrate and polyvinylpyrrolidone as a synthetic water-soluble polymer. Example 10 is an example of using sorbitol as a carbohydrate and polyethylene glycol as a synthetic water-soluble polymer. Example 11 is an example in which carbohydrates are used in combination with xylitol and sorbitol (a combination of sugar alcohols with each other), and similarly Example 12 is an example in which carbohydrates are used in combination with mannitol and glucose (a combination example of sugar alcohols and monosaccharides). Example 13 is an example of changing the soluble copper salt based on Example 1, and Example 14 is an example of changing the soluble copper salt based on Example 4. Examples 15 to 16 are based on Example 1 to change the colloid stabilizer, and Example 17 are based on Example 4 to change the colloid stabilizer. Example 18 is an example of changing the reducing agent based on Example 4, and Example 19 is an example of changing the reducing agent based on Example 5. Example 20 is an example of changing the pH value of the catalytic solution to the weakly alkaline region on the basis of Example 1.

In addition, Example 4 and Example 11 are examples in which the pickling step is inserted after the catalyst-imparting step and before the electroless copper-plating step. Other examples do not perform acid-washing, and sequentially perform adsorption promotion→catalyst imparting→electroless copper-plating steps example.

On the other hand, in the following Comparative Examples 1 to 3, Comparative Example 1 is a blank example in which the two components of colloidal stabilizer and carbohydrate are not contained in the catalytic solution. Comparative example 2 is contained in the catalytic solution Examples of colloidal stabilizers containing carbohydrates (starch) different from the carbohydrates specified in the present invention. Comparative Example 3 is a blank example in which the electroless plating step is performed directly from the catalyst application step without the adsorption promotion step.

In addition, the reference example is based on the above-mentioned first application invention, and therefore is an example in which the catalytic solution contains the colloidal stabilizer but does not contain the carbohydrate specified in the present invention.

(1) Example 1

"Processing steps for adsorption promotion, catalyst addition, and electroless plating"

First, a double-sided copper-clad glass-epoxy resin substrate (FR-4 manufactured by Matsushita Electric Works Co., Ltd., plate thickness: 1.0 mm) was used as a sample substrate.

Then, the sample substrate is subjected to adsorption promotion using an adsorption promoter described in (a) described later, and then immersed in a catalyst solution described in (b) described below to provide catalyst, and then electroless copper plating is performed using a plating solution described in (c) described later.

Specifically, the sample substrate was immersed in the liquid containing the adsorption accelerator under the conditions of 50° C. and 2 minutes, and then washed with pure water. Next, the sample substrate subjected to the adsorption promotion treatment (pretreatment) was immersed in the above copper colloidal catalytic solution at 25° C. for 10 minutes, and washed with pure water. Then, the sample substrate after the catalyst application was immersed in the above-mentioned electroless copper plating solution, and electroless plating was performed under the conditions of 50° C. and 10 minutes. After the copper film was formed on the sample substrate, it was washed with pure water and dried.

(a) Preparation of liquid containing adsorption promoter

The liquid containing the adsorption accelerator was prepared according to the following composition.

[Liquid containing adsorption accelerator]

Quaternary ammonium salt of diallylamine polymer: 5g/L

Polyoxyethylene side chain decyl ether: 1g/L

pH value: 10.0

(b) Preparation of copper colloidal catalytic solution

[Copper solution]

Copper sulfate (calculated as Cu ²⁺ ): 0.1 mol/L

Citric acid: 0.2 mol/L

Xylitol: 0.3 moles/L

[Reducing agent solution]

Sodium borohydride: 0.02 mol/L

Hypophosphorous acid: 0.18 mol/L

The reducing agent solution was dropped into the above copper solution adjusted to pH 4.0 at 25°C and stirred for 45 minutes to prepare a copper colloidal catalytic solution.

The molar ratios of the components of the above catalytic solution are as follows: copper salt: colloidal stabilizer=1:2, copper salt: carbohydrate=1:3, copper salt: reducing agent=1:2.

The average particle diameter of the generated copper colloidal particles was about 15 nm.

(c) Preparation of electroless copper plating solution

The electroless copper plating bath (built bath) was made according to the following composition. This plating solution adjusts pH value with sodium hydroxide mentioned later.

[Electroless copper plating solution]

Copper sulfate pentahydrate (calculated as Cu ²⁺ ): 2.0g/L

Formaldehyde: 5.0g/L

EDTA: 30.0g/L

Sodium hydroxide: 9.6g/L

Balance: pure water

pH value (20℃): 12.8

(2) Example 2

Based on the above Example 1, a copper colloidal catalytic solution was prepared according to the following composition, in addition to the composition of the liquid containing the adsorption promoter, the electroless copper plating solution, and the steps of adsorption promotion, catalyst addition, and electroless copper plating The conditions are the same as in Example 1.

(b) Preparation of copper colloidal catalytic solution

[Copper solution]

Copper sulfate (calculated as Cu ²⁺ ): 0.1 mol/L

Citric acid: 0.2 mol/L

Xylitol: 0.001 mol/L

[Reducing agent solution]

Sodium borohydride: 0.02 mol/L

Hypophosphorous acid: 0.18 mol/L

The reducing agent solution was dropped into the above copper solution adjusted to pH 4.0 at 25°C and stirred for 45 minutes to prepare a copper colloidal catalytic solution.

The molar ratios of the components of the above catalytic solution are as follows: copper salt: colloidal stabilizer=1:2, copper salt: carbohydrate=1:0.01, copper salt: reducing agent=1:2.

The average particle diameter of the generated copper colloidal particles is about 25 nm.

(3) Example 3

Based on the above Example 1, a copper colloidal catalytic solution was prepared according to the following composition, in addition to the composition of the liquid containing the adsorption promoter, the electroless copper plating solution, and the steps of adsorption promotion, catalyst addition, and electroless copper plating The conditions are the same as in Example 1.

(b) Preparation of copper colloidal catalytic solution

[Copper solution]

Copper sulfate (calculated as Cu ²⁺ ): 0.1 mol/L

Citric acid: 0.2 mol/L

Xylitol: 4.0 moles/L

[Reducing agent solution]

Sodium borohydride: 0.02 mol/L

Hypophosphorous acid: 0.18 mol/L

The reducing agent solution was dropped into the above copper solution adjusted to pH 4.0 at 25°C and stirred for 45 minutes to prepare a copper colloidal catalytic solution.

The molar ratios of the components of the above catalytic solution are as follows: copper salt: colloidal stabilizer=1:2, copper Salt: carbohydrate = 1:40, copper salt: reducing agent = 1:2.

The average particle diameter of the generated copper colloidal particles is about 10 nm.

(4) Example 4

Examples of the steps of accelerating adsorption, providing catalyst, pickling, and electroless copper plating are performed in this order.

In addition, the processing conditions of each step of the adsorption promotion, catalyst addition, electroless copper plating, and the composition of the electroless copper plating solution are the same as in Example 1, and the preparation conditions of the liquid containing the adsorption accelerator and the copper colloidal catalytic solution are shown below.

In addition, the processing conditions of pickling are as shown in (d) mentioned later.

(a) Preparation of liquid containing adsorption promoter

The liquid containing the adsorption accelerator was prepared according to the following composition.

[Liquid containing adsorption accelerator]

Dodecyl dimethyl benzyl ammonium chloride: 5g/L

Polyoxyethylene side chain decyl ether: 1g/L

pH value: 9.0

(b) Preparation of copper colloidal catalytic solution

[Copper solution]

Copper sulfate (calculated as Cu ²⁺ ): 0.1 mol/L

Citric acid: 0.2 mol/L

Sorbitol: 0.3 mol/L

[Reducing agent solution]

Sodium borohydride: 0.02 mol/L

Hypophosphorous acid: 0.18 mol/L

The reducing agent solution was dropped into the above copper solution adjusted to pH 4.0 at 25°C and stirred for 45 minutes to prepare a copper colloidal catalytic solution.

The molar ratios of the components of the above catalytic solution are as follows: copper salt: colloidal stabilizer=1:2, copper salt: carbohydrate=1:3, copper salt: reducing agent=1:2.

The average particle diameter of the generated copper colloidal particles is about 40 nm.

(d) Treatment conditions for pickling

A 50 g/L sulfuric acid washing liquid was prepared, and the sample substrate after the catalyst application treatment was immersed in the washing liquid at 45° C. for 1 minute, washed with water, and then subjected to the next step of electroless copper plating.

(5) Example 5

The processing conditions of the steps of adsorption promotion, catalyst addition, electroless copper plating, and the composition of the electroless copper plating solution are the same as in Example 1. The preparation conditions of the liquid containing the adsorption accelerator and the copper colloidal catalytic solution are as follows:

(a) Preparation of liquid containing adsorption promoter

The liquid containing the adsorption accelerator was prepared according to the following composition.

[Liquid containing adsorption accelerator]

Dodecyl dimethyl glycine betaine: 5g/L

Polyoxyethylene octyl phenyl ether: 1g/L

pH value: 10.5

(b) Preparation of copper colloidal catalytic solution

[Copper solution]

Copper sulfate (calculated as Cu ²⁺ ): 0.1 mol/L

Citric acid: 0.2 mol/L

Mannitol: 0.3 mol/L

[Reducing agent solution]

Sodium borohydride: 0.02 mol/L

Hypophosphorous acid: 0.18 mol/L

The reducing agent solution was dropped into the above copper solution adjusted to pH 4.0 at 25°C and stirred for 45 minutes to prepare a copper colloidal catalytic solution.

The molar ratios of the components of the above catalytic solution are as follows: copper salt: colloidal stabilizer=1:2, copper salt: carbohydrate=1:3, copper salt: reducing agent=1:2.

The average particle diameter of the generated copper colloidal particles is about 25 nm.

(6) Example 6

The processing conditions of each step of adsorption promotion, catalyst addition, electroless copper plating, and the composition of the liquid containing the adsorption promoter and the electroless copper plating solution are the same as in Example 1, and the preparation conditions of the copper colloidal catalytic solution are as follows:

(b) Preparation of copper colloidal catalytic solution

[Copper solution]

Copper sulfate (calculated as Cu ²⁺ ): 0.1 mol/L

Citric acid: 0.2 mol/L

Gluconolactone: 0.3 mol/L [reducing agent solution]

Sodium borohydride: 0.02 mol/L

Hypophosphorous acid: 0.18 mol/L

The reducing agent solution was dropped into the above copper solution adjusted to pH 4.0 at 25°C and stirred for 45 minutes to prepare a copper colloidal catalytic solution.

The molar ratios of the components of the above catalytic solution are as follows: copper salt: colloidal stabilizer=1:2, copper salt: carbohydrate=1:3, copper salt: reducing agent=1:2.

The average particle diameter of the generated copper colloidal particles is about 20 nm.

(7) Example 7

The adsorption conditions, catalyst addition, processing conditions of each step of electroless copper plating, and the composition of the liquid containing the adsorption promoter and the electroless copper plating solution are the same as in Example 1, and the preparation conditions of the copper colloidal catalytic solution are shown below.

(b) Preparation of copper colloidal catalytic solution

[Copper solution]

Copper sulfate (calculated as Cu ²⁺ ): 0.1 mol/L

Citric acid: 0.2 mol/L

Glucose: 0.3 mol/L

[Reducing agent solution]

Sodium borohydride: 0.02 mol/L

Hypophosphorous acid: 0.18 mol/L

The reducing agent solution was dropped into the above copper solution adjusted to pH 4.0 at 25°C and stirred for 45 minutes to prepare a copper colloidal catalytic solution.

The molar ratios of the components of the above catalytic solution are as follows: copper salt: colloidal stabilizer=1:2, copper salt: carbohydrate=1:3, copper salt: reducing agent=1:2.

The average particle diameter of the generated copper colloidal particles was about 15 nm.

(8) Example 8

The processing conditions of the steps of adsorption promotion, catalyst addition, electroless copper plating, and the composition of the electroless copper plating solution are the same as in Example 1, and the preparation conditions of the liquid containing the adsorption accelerator and the copper colloidal catalytic solution are shown below.

(a) Preparation of liquid containing adsorption promoter

The liquid containing the adsorption accelerator was prepared according to the following composition.

[Liquid containing adsorption accelerator]

Dodecyl dimethyl benzyl ammonium chloride: 5g/L

Polyoxyethylene octyl phenyl ether: 1g/L

pH value: 10.5

(b) Preparation of copper colloidal catalytic solution

[Copper solution]

Copper sulfate (calculated as Cu ²⁺ ): 0.1 mol/L

Citric acid: 0.2 mol/L

Maltose: 0.3 mol/L

[Reducing agent solution]

Sodium borohydride: 0.02 mol/L

Hypophosphorous acid: 0.18 mol/L

The reducing agent solution was dropped into the above copper solution adjusted to pH 4.0 at 25° C. and stirred for 60 minutes to prepare a copper colloidal catalytic solution.

The molar ratios of the components of the above catalytic solution are as follows: copper salt: colloidal stabilizer=1:2, copper salt: carbohydrate=1:3, copper salt: reducing agent=1:2.

The average particle diameter of the generated copper colloidal particles is about 10 nm.

(9) Example 9

The processing conditions of the steps of adsorption promotion, catalyst addition, electroless copper plating, and the composition of the electroless copper plating solution are the same as in Example 1, and the preparation conditions of the liquid containing the adsorption accelerator and the copper colloidal catalytic solution are shown below.

(a) Preparation of liquid containing adsorption promoter

The liquid containing the adsorption accelerator was prepared according to the following composition.

[Liquid containing adsorption accelerator]

Dodecyl dimethyl glycine beetroot: 5g/L

Polyoxyethylene octyl phenyl ether: 1g/L

pH value: 10.0

(b) Preparation of copper colloidal catalytic solution

[Copper solution]

Copper sulfate (calculated as Cu ²⁺ ): 0.1 mol/L

Citric acid: 0.2 mol/L

Xylitol: 0.3 moles/L

Polyvinylpyrrolidone (average molecular weight 40000): 2.0g/L

[Reducing agent solution]

Sodium borohydride: 0.02 mol/L

Hypophosphorous acid: 0.18 mol/L

The reducing agent solution was added dropwise to the copper solution at 25°C adjusted to pH 3.0 and stirred for 45 minutes to prepare Copper colloidal catalytic solution.

The molar ratios of the components of the above catalytic solution are as follows: copper salt: colloidal stabilizer=1:2, copper salt: carbohydrate=1:3, copper salt: reducing agent=1:2.

The average particle diameter of the generated copper colloidal particles is about 25 nm.

(10) Example 10

The processing conditions of the steps of adsorption promotion, catalyst addition, electroless copper plating, and the composition of the electroless copper plating solution are the same as in Example 1, and the preparation conditions of the liquid containing the adsorption accelerator and the copper colloidal catalytic solution are shown below.

(a) Preparation of liquid containing adsorption promoter

The liquid containing the adsorption accelerator was prepared according to the following composition.

[Liquid containing adsorption accelerator]

Dodecyl dimethyl benzyl ammonium chloride: 5g/L

Polyoxyethylene side chain decyl ether: 1g/L

pH value: 10.0

(b) Preparation of copper colloidal catalytic solution

[Copper solution]

Copper sulfate (calculated as Cu ²⁺ ): 0.1 mol/L

Citric acid: 0.2 mol/L

Sorbitol: 0.3 mol/L

Polyethylene glycol (average molecular weight 10000): 1.0g/L

[Reducing agent solution]

Sodium borohydride: 0.02 mol/L

Hypophosphorous acid: 0.18 mol/L

The reducing agent solution was dropped into the above copper solution adjusted to pH 4.0 at 25° C. and stirred for 90 minutes to prepare a copper colloidal catalytic solution.

The molar ratios of the components of the above catalytic solution are as follows: copper salt: colloidal stabilizer=1:2, copper Salt: Carbohydrate=1:3, Copper Salt: Reductant=1:2.

The average particle diameter of the generated copper colloidal particles was about 35 nm.

(11) Example 11

Examples of the steps of accelerating adsorption, providing catalyst, pickling, and electroless copper plating are performed in this order.

However, the processing conditions of each step of the adsorption promotion, catalyst addition, electroless copper plating, and the composition of the liquid containing the adsorption promoter and the electroless copper plating solution are the same as in Example 1, and the preparation conditions of the copper colloidal catalytic solution are shown below.

In addition, the processing conditions of pickling are as shown in (d) mentioned later.

(b) Preparation of copper colloidal catalytic solution

[Copper solution]

Copper sulfate (calculated as Cu ²⁺ ): 0.1 mol/L

Citric acid: 0.2 mol/L

Sorbitol: 0.2 mol/L

Xylitol: 0.1 mol/L

[Reducing agent solution]

Sodium borohydride: 0.02 mol/L

Hypophosphorous acid: 0.18 mol/L

The reducing agent solution was dropped into the above-mentioned copper solution adjusted to pH 4.0 at 35°C and stirred for 45 minutes to prepare a copper colloidal catalytic solution.

The molar ratios of the components of the above catalytic solution are as follows: copper salt: colloidal stabilizer=1:2, copper salt: carbohydrate=1:3, copper salt: reducing agent=1:2.

The average particle diameter of the generated copper colloidal particles is about 25 nm.

(d) Treatment conditions for pickling

A 50 g/L sulfuric acid washing liquid was prepared, and the sample substrate after the catalyst application treatment was immersed in the washing liquid at 45° C. for 1 minute, washed with water, and then subjected to the next step of electroless copper plating.

(12) Example 12

The processing conditions of the steps of adsorption promotion, catalyst addition, electroless copper plating, and the composition of the electroless copper plating solution are the same as in Example 1, and the preparation conditions of the liquid containing the adsorption accelerator and the copper colloidal catalytic solution are shown below.

(a) Preparation of liquid containing adsorption promoter

The liquid containing the adsorption accelerator was prepared according to the following composition.

[Liquid containing adsorption accelerator]

Dodecyl dimethyl benzyl ammonium chloride: 5g/L

Polyoxyethylene side chain decyl ether: 1g/L

pH value: 8.5

(b) Preparation of copper colloidal catalytic solution

[Copper solution]

Copper sulfate (calculated as Cu ²⁺ ): 0.1 mol/L

Citric acid: 0.2 mol/L

Mannitol: 0.2 mol/L

Glucose: 0.2 mol/L

[Reducing agent solution]

Sodium borohydride: 0.02 mol/L

Hypophosphorous acid: 0.18 mol/L

The reducing agent solution was dropped into the above-mentioned copper solution adjusted to pH 3.0 at 35° C. for 45 minutes to prepare a copper colloidal catalytic solution.

The molar ratios of the components of the above catalytic solution are as follows: copper salt: colloidal stabilizer=1:2, copper salt: carbohydrate=1:4, copper salt: reducing agent=1:2.

The average particle diameter of the generated copper colloidal particles was about 15 nm.

(13) Example 13

Adsorption promotion, catalyst addition, processing conditions of each step of electroless copper plating, and the composition of the liquid containing the adsorption promoter and the electroless copper plating solution are the same as in Example 1, and the preparation of the copper colloidal catalytic solution The conditions are as follows.

(b) Preparation of copper colloidal catalytic solution

[Copper solution]

Copper methanesulfonate (calculated as Cu ²⁺ ): 0.1 mol/L

Citric acid: 0.2 mol/L

Xylitol: 0.3 moles/L

[Reducing agent solution]

Sodium borohydride: 0.02 mol/L

Hypophosphorous acid: 0.18 mol/L

The reducing agent solution was dropped into the above-mentioned copper solution adjusted to pH 5.0 at 35°C and stirred for 45 minutes to prepare a copper colloidal catalytic solution.

The molar ratios of the components of the above catalytic solution are as follows: copper salt: colloidal stabilizer=1:2, copper salt: carbohydrate=1:3, copper salt: reducing agent=1:2.

The average particle diameter of the generated copper colloidal particles is about 10 nm.

(14) Embodiment 14

The adsorption conditions, catalyst addition, processing conditions of each step of electroless copper plating, and the composition of the liquid containing the adsorption promoter and the electroless copper plating solution are the same as in Example 1, and the preparation conditions of the copper colloidal catalytic solution are shown below.

(b) Preparation of copper colloidal catalytic solution

[Copper solution]

Copper citrate (calculated as Cu ²⁺ ): 0.1 mol/L

Citric acid: 0.2 mol/L

Sorbitol: 0.3 mol/L

[Reducing agent solution]

Sodium borohydride: 0.02 mol/L

Hypophosphorous acid: 0.18 mol/L

The reducing agent solution was dropped into the above-mentioned copper solution adjusted to pH 5.0 at 35°C and stirred for 45 minutes to prepare a copper colloidal catalytic solution.

The molar ratios of the components of the above catalytic solution are as follows: copper salt: colloidal stabilizer=1:2, copper salt: carbohydrate=1:3, copper salt: reducing agent=1:2.

The average particle diameter of the generated copper colloidal particles is about 25 nm.

(15) Example 15

The adsorption conditions, catalyst addition, processing conditions of each step of electroless copper plating, and the composition of the liquid containing the adsorption promoter and the electroless copper plating solution are the same as in Example 1, and the preparation conditions of the copper colloidal catalytic solution are shown below.

(b) Preparation of copper colloidal catalytic solution

[Copper solution]

Copper sulfate (calculated as Cu ²⁺ ): 0.1 mol/L

Formic acid: 0.2 mol/L

Xylitol: 0.3 moles/L

[Reducing agent solution]

Sodium borohydride: 0.02 mol/L

Hypophosphorous acid: 0.18 mol/L

The reducing agent solution was dropped into the above-mentioned copper solution adjusted to pH 4.0 at 35°C and stirred for 45 minutes to prepare a copper colloidal catalytic solution.

The molar ratios of the components of the above catalytic solution are as follows: copper salt: colloidal stabilizer=1:2, copper salt: carbohydrate=1:3, copper salt: reducing agent=1:2.

The average particle diameter of the generated copper colloidal particles was about 15 nm.

(16) Example 16

The adsorption conditions, catalyst addition, processing conditions of each step of electroless copper plating, and the composition of the liquid containing the adsorption promoter and the electroless copper plating solution are the same as in Example 1, and the preparation conditions of the copper colloidal catalytic solution are shown below.

(b) Preparation of copper colloidal catalytic solution

[Copper solution]

Copper sulfate (calculated as Cu ²⁺ ): 0.1 mol/L

Lactic acid: 0.2 mol/L

Xylitol: 0.3 moles/L

[Reducing agent solution]

Sodium borohydride: 0.02 mol/L

Hypophosphorous acid: 0.18 mol/L

The reducing agent solution was dropped into the above-mentioned copper solution adjusted to pH 4.0 at 35°C and stirred for 45 minutes to prepare a copper colloidal catalytic solution.

The molar ratios of the components of the above catalytic solution are as follows: copper salt: colloidal stabilizer=1:2, copper salt: carbohydrate=1:3, copper salt: reducing agent=1:2.

The average particle diameter of the generated copper colloidal particles is about 10 nm.

(17) Example 17

The adsorption conditions, catalyst addition, processing conditions of each step of electroless copper plating, and the composition of the liquid containing the adsorption promoter and the electroless copper plating solution are the same as in Example 1, and the preparation conditions of the copper colloidal catalytic solution are shown below.

(b) Preparation of copper colloidal catalytic solution

[Copper solution]

Copper sulfate (calculated as Cu ²⁺ ): 0.1 mol/L

Ammonia triacetic acid: 0.2 mol/L

Sorbitol: 0.3 mol/L

[Reducing agent solution]

Sodium borohydride: 0.02 mol/L

Hypophosphorous acid: 0.18 mol/L

The reducing agent solution was added dropwise to the copper solution at 35°C adjusted to pH 4.0 and stirred for 45 minutes to prepare Copper colloidal catalytic solution.

The molar ratios of the components of the above catalytic solution are as follows: copper salt: colloidal stabilizer=1:2, copper salt: carbohydrate=1:3, copper salt: reducing agent=1:2.

The average particle diameter of the generated copper colloidal particles was about 15 nm.

(18) Example 18

The adsorption conditions, catalyst addition, processing conditions of each step of electroless copper plating, and the composition of the liquid containing the adsorption promoter and the electroless copper plating solution are the same as in Example 1, and the preparation conditions of the copper colloidal catalytic solution are shown below.

(b) Preparation of copper colloidal catalytic solution

[Copper solution]

Copper sulfate (calculated as Cu ²⁺ ): 0.1 mol/L

Citric acid: 0.2 mol/L

Sorbitol: 0.3 mol/L

[Reducing agent solution]

Dimethylamine borane: 0.02 mol/L

Ascorbic acid: 0.18 mol/L

The reducing agent solution was dropped into the above copper solution adjusted to pH 4.0 at 25°C and stirred for 45 minutes to prepare a copper colloidal catalytic solution.

The molar ratios of the components of the above catalytic solution are as follows: copper salt: colloidal stabilizer=1:2, copper salt: carbohydrate=1:3, copper salt: reducing agent=1:2.

The average particle diameter of the generated copper colloidal particles is about 25 nm.

(19) Example 19

The adsorption conditions, catalyst addition, processing conditions of each step of electroless copper plating, and the composition of the liquid containing the adsorption promoter and the electroless copper plating solution are the same as in Example 1, and the preparation conditions of the copper colloidal catalytic solution are shown below.

(b) Preparation of copper colloidal catalytic solution

[Copper solution]

Copper sulfate (calculated as Cu ²⁺ ): 0.1 mol/L

Citric acid: 0.2 mol/L

Mannitol: 0.3 mol/L

[Reducing agent solution]

Dimethylamine borane: 0.02 mol/L

Ascorbic acid: 0.18 mol/L

The reducing agent solution was dropped into the above copper solution adjusted to pH 4.0 at 25°C and stirred for 45 minutes to prepare a copper colloidal catalytic solution.

The molar ratios of the components of the above catalytic solution are as follows: copper salt: colloidal stabilizer=1:2, copper salt: carbohydrate=1:3, copper salt: reducing agent=1:2.

The average particle diameter of the generated copper colloidal particles was about 15 nm.

(20) Example 20

The adsorption conditions, catalyst addition, processing conditions of each step of electroless copper plating, and the composition of the liquid containing the adsorption promoter and the electroless copper plating solution are the same as in Example 1, and the preparation conditions of the copper colloidal catalytic solution are shown below.

(b) Preparation of copper colloidal catalytic solution

[Copper solution]

Copper sulfate (calculated as Cu ²⁺ ): 0.1 mol/L

EDTA: 0.2 mol/L

Xylitol: 0.3 moles/L

[Reducing agent solution]

Dimethylamine borane: 0.02 mol/L

Ascorbic acid: 0.18 mol/L

The reducing agent solution was dropped into the above copper solution adjusted to pH 9.0 at 25°C and stirred for 45 minutes to prepare a copper colloidal catalytic solution.

The molar ratios of the components of the above catalytic solution are as follows: copper salt: colloidal stabilizer=1:2, copper salt: carbohydrate=1:3, copper salt: reducing agent=1:2.

The average particle diameter of the generated copper colloidal particles is about 30 nm.

(21) Comparative Example 1

Based on the above Example 1, but a blank example in which the copper colloidal catalytic solution does not contain colloidal stabilizers and carbohydrates.

That is, the processing conditions of each step of the adsorption promotion, catalyst addition, electroless copper plating, and the composition of the liquid containing the adsorption promoter and the electroless copper plating solution are the same as in Example 1, and the preparation conditions of the copper colloidal catalytic solution are shown below.

(b) Preparation of copper colloidal catalytic solution

[Copper solution]

Copper sulfate (calculated as Cu ²⁺ ): 0.1 mol/L

[Reducing agent solution]

Sodium borohydride: 0.02 mol/L

Hypophosphorous acid: 0.18 mol/L

The reducing agent solution was dropped into the above copper solution adjusted to pH 4.0 at 25°C and stirred for 45 minutes to prepare a copper colloidal catalytic solution.

The molar ratios of the components of the above catalytic solution are as follows: copper salt: colloidal stabilizer=1:0, copper salt: reducing agent=1:2.

Copper colloidal particles are generated, but aggregation and precipitation occur.

(22) Comparative Example 2

Based on the above Example 1, the copper colloidal catalytic solution contains an example of a colloidal stabilizer and a carbohydrate (starch) different from the provisions of the present invention.

That is, the processing conditions of each step of the adsorption promotion, catalyst addition, electroless copper plating, and the composition of the liquid containing the adsorption promoter and the electroless copper plating solution are the same as in Example 1, and the preparation conditions of the copper colloidal catalytic solution are shown below.

(b) Preparation of copper colloidal catalytic solution

[Copper solution]

Copper sulfate (calculated as Cu ²⁺ ): 0.1 mol/L

Citric acid: 0.2 mol/L

Starch: 0.3 mol/L

[Reducing agent solution]

Sodium borohydride: 0.02 mol/L

Hypophosphorous acid: 0.18 mol/L

The reducing agent solution was dropped into the above copper solution adjusted to pH 4.0 at 25°C and stirred for 45 minutes to prepare a copper colloidal catalytic solution.

The molar ratios of the components of the above catalytic solution are as follows: copper salt: colloidal stabilizer = 1:2, copper salt: carbohydrate (starch) = 1:3, copper salt: reducing agent = 1:2.

The average particle diameter of the generated copper colloidal particles is about 200 nm.

(23) Comparative Example 3

Based on the above-mentioned Embodiment 1, the example of the adsorption promotion step is omitted.

That is, the sample substrate was not subjected to the adsorption promotion treatment, and was directly immersed in the catalytic solution (b) of Example 1 to provide the catalyst, and then electroless copper plating was performed using the plating solution (c) of Example 1. The catalyst addition, the processing conditions of the electroless copper plating steps, and the preparation conditions of the copper colloidal catalytic solution and the electroless copper plating liquid are the same as in Example 1.

(24) Reference example

In accordance with the above-mentioned first application invention, based on the above Example 1, the catalytic solution contains a colloidal stabilizer but no carbohydrates.

That is, the processing conditions of each step of the adsorption promotion, catalyst addition, electroless copper plating, and the composition of the liquid containing the adsorption promoter and the electroless copper plating solution are the same as in Example 1, and the preparation conditions of the copper colloidal catalytic solution are shown below.

(b) Preparation of copper colloidal catalytic solution

[Copper solution]

Copper sulfate (calculated as Cu ²⁺ ): 0.1 mol/L

Citric acid: 0.2 mol/L

[Reducing agent solution]

Sodium borohydride: 0.02 mol/L

Hypophosphorous acid: 0.18 mol/L

The reducing agent solution was dropped into the above copper solution adjusted to pH 4.0 at 25°C and stirred for 45 minutes to prepare a copper colloidal catalytic solution.

The molar ratios of the components of the above catalytic solution are as follows: copper salt: colloidal stabilizer=1:2, copper salt: carbohydrate (starch)=1:0, copper salt: reducing agent=1:2.

The average particle diameter of the generated copper colloidal particles is about 30 nm.

"Experimental Example of Stability of Catalytic Solution"

Thus, for each of the copper colloidal catalytic solutions in the above-mentioned Examples 1 to 20, Comparative Examples 1 to 3, and the reference example, the quality of the colloidal stability was evaluated according to the following criteria.

◎: No precipitation or decomposition occurred more than 2 months after the bath was built.

○: Precipitation or decomposition occurred within 1 month to 2 months after the bath was established.

△: Precipitation or decomposition occurred within 1 month after the bath was established.

×: No colloidal particles were formed, or precipitated or decomposed immediately after the bath was established.

"Experimental Evaluation Test Example of Copper Film Precipitated by Electroless Copper Plating"

Next, for each of the copper colloidal catalyst solutions for bathing in the above Examples 1 to 20, Comparative Examples 1 to 3, and the reference example, the quality of the appearance of the copper plating film obtained by using the catalytic solution at the initial stage of bathing was visually evaluated according to the following criteria.

○: The copper plating film is uniform and free of streaks.

△: The copper plating film has streaks or partial precipitation (defect of the plating film).

×: The copper film did not precipitate.

It should be noted that the “marking” of the deposited film means that the denseness or smoothness of the film is present, which is not related to the surroundings. The same part. The "marking" of the coating is different from the uniformity of the coating.

"Test results on the stability of copper colloidal catalytic solution over time and the appearance of the coating"

"Comprehensive Evaluation of the Stability of the Catalytic Solution over Time and the Appearance of the Coating"

In Comparative Example 1 in which the copper colloidal catalytic solution did not contain colloidal stabilizers and carbohydrates, the catalytic solution had poor stability over time, and even after contacting the catalytic solution, the non-conductive substrate was chemically modified. The copper coating was not precipitated by the plating.

On the other hand, in the reference example in which the catalytic solution contains a colloidal stabilizer and no carbohydrates, it shows good stability over time after precipitation of the catalytic solution after the bath is established, and the appearance of the copper film is good.

However, in the catalytic solution in which the colloidal stabilizer and the carbohydrate coexist, a starch different from the specific carbohydrate specified in the present invention is used as the comparative example 2 of the carbohydrate, and the stability decreases over time so that the copper particles generated by the catalytic solution It is not fine, and the formed copper film is defective in plating, and the appearance of the film is problematic.

In Comparative Example 3 where electroless copper plating was carried out without performing the adsorption promotion treatment on the non-conductive substrate, the time stability of the catalytic solution was the same as in the example, but the deposited copper film had a coating defect, so it was possible It was judged that since the catalyst was not subjected to pretreatment for adsorption promotion before the catalyst was provided, the catalyst activity was insufficient, and the adsorption of the copper colloidal particles on the substrate was inferior to that of the examples.

On the other hand, after performing the adsorption promotion pretreatment, the catalyst addition treatment, followed by the electroless copper plating of Examples 1 to 20, the catalytic solution was excellent in stability over time, and the copper film deposited by the electroless plating was almost free of streaks Or the coating is defective, showing an excellent appearance.

The comparison between the above-mentioned reference example and Comparative Example 1 shows that in order to obtain a copper film with good appearance without streaks or coating defects, the catalytic solution must contain not only a copper salt and a reducing agent, but also a colloidal stabilizer.

On the other hand, it can be seen from the comparison between the above Examples 1 to 20 and the reference example that in order to obtain a copper film having an excellent appearance, it is necessary to coexist the colloidal stabilizer and the specific carbohydrate of the present invention in the catalytic solution. In particular, focusing on the stability over time of the catalytic solution, although the reference example shows a stability evaluation of more than 1 month after the bath establishment, the catalytic solutions of Examples 1 to 20 show more than 2 months after the bath establishment. Stability, indicating that for this time-dependent stability, each of the catalytic solutions of Examples 1 to 20 has advantages over the reference example, and has the ability to make the maintenance of the catalytic solution more simplified than the reference example, thereby reducing the treatment of electroless copper plating Cost advantage.

In addition, comparing Comparative Example 2 and Examples 1 to 20 using a starch different from the specific carbohydrate specified in the present invention, it can be seen that even in the case where the colloidal stabilizer and the carbohydrate coexist in the catalytic solution, if this option is not selected The specific carbohydrates specified in the invention will not improve the temporal stability of the catalytic solution, but will not form fine copper colloid particles smoothly, which will damage the appearance of the coating. Therefore, it can be judged that the selection of specific carbohydrates can improve the catalytic solution. The importance of time stability.

Next, Examples 1 to 20 will be discussed in detail.

Based on Example 1, the relative evaluation with other examples will be described. First, in Example 1, a non-conductive substrate was pretreated with an adsorption accelerator containing a quaternary ammonium salt of a diallylamine polymer, which is a cationic surfactant, using copper sulfate as a copper salt and sodium borohydride as a reducing agent. The catalytic solution of citric acid as a colloidal stabilizer and xylitol as a specific carbohydrate is given as an example of electroless copper plating. The catalytic solution has good stability over time, and no precipitation or decomposition occurs after 2 months after the bath is established. In addition, the copper coating obtained by the electroless plating did not show precipitation spots or plating defects, and exhibited an excellent appearance.

Example 2 is an example in which the content of carbohydrate is greatly reduced compared to Example 1, and Example 3 is an example in which the content of carbohydrate is greatly increased. In the same way as Example 1, the stability of the catalytic solution over time is good, and the resulting copper film appears Outstanding appearance.

Example 4 in which carbohydrate was changed to sorbitol (sugar alcohol), Example 5 in which it was also changed to mannitol (sugar alcohol), Example 6 in which it was changed to gluconolactone (monosaccharide derivative), and it was changed to glucose Example 7 of (monosaccharides), Example 8 changed to maltose (disaccharide), Example 11 changed to sorbitol and xylitol (combination of sugar alcohols with each other), mannitol and glucose (sugar alcohol and monosaccharides) In the example 12 of (combined use of ), all of them showed high stability over time and excellent appearance of the coating as in example 1.

Based on the catalytic solution of Example 1 containing xylitol, PVP (average molecular weight of 40,000) was added to the catalytic solution as a water-soluble polymer in Example 9, the time-dependent stability of the catalytic solution and the appearance and implementation of the coating The evaluation of Example 1 is the same.

Based on the catalytic solution of Example 4 containing sorbitol, add to the catalytic solution In Example 10 in which PEG (average molecular weight 10,000) was added as a water-soluble polymer, the time-dependent stability of the catalytic solution and the appearance of the coating film were the same as the evaluation in Example 4.

In addition, even if the soluble copper salt, colloidal stabilizer, and reducing agent (refer to Examples 13 to 19) were changed on the basis of Examples 1, 4, or 5, the same high-time stability and the same as in each basic example were exhibited. Excellent coating appearance.

With respect to Example 1 where the catalytic solution was set to pH 4.0, Example 20 which was set to pH 9 on the weakly alkaline side also showed high stability over time and excellent film appearance.

Example 4 and Example 11 are both examples of pickling after the catalyst-imparting treatment and then electroless copper plating. Compared with other examples, there is no particular difference in the appearance of the coating, even if heat treatment is performed between the coating surface and the substrate There is no change, and high adhesion can be confirmed.

Claims (8)

A copper colloidal catalytic solution for electroless copper plating is a copper colloidal catalytic solution for contacting with a non-conductive substrate subjected to electroless copper plating for catalyst endowment, which is characterized by containing: (A) soluble copper salt; (B) reduction Agent; (C) at least one colloidal stabilizer selected from monocarboxylic acids, hydroxycarboxylic acids, aminocarboxylic acids, and polycarboxylic acids; and (D) selected from glucose, fructose, lactose, maltol, pie At least one of carbohydrates in latinose, xylose, sorbitol, xylitol, mannitol, maltitol, erythritol, reduced starch syrup, lactitol, reduced palmitan, and gluconolactone. The copper colloidal catalytic solution for electroless copper plating according to claim 1, wherein the molar ratio of the soluble salt (A) to the colloidal stabilizer (C) is A: C=1: 0.03 ~1:35. The copper colloidal catalytic solution for electroless copper plating according to claim 1 or 2, characterized in that the copper colloidal catalytic solution for electroless copper plating further contains a polyethylene glycol, polypropylene glycol, polyvinylpyrrolidone, poly At least one of synthetic water-soluble polymers among vinyl alcohol, polypropylene amide, and polyethyleneimine. The copper colloidal catalytic solution for electroless copper plating according to claim 1 or 2, wherein the reducing agent (B) is selected from the group consisting of boron hydride compounds, amine boranes, hypophosphorous acids, aldehydes, and ascorbic acid At least one of hydrazines, polyhydric phenols, polyhydric naphthols, phenol sulfonic acids, naphthol sulfonic acids, and sulfinic acids. The copper colloidal catalytic solution for electroless copper plating according to claim 1 or 2, characterized in that: The monocarboxylic acids in the colloidal stabilizer (C) are selected from formic acid, acetic acid, propionic acid, butyric acid, valeric acid, caproic acid, caprylic acid, capric acid, lauric acid, myristic acid, palmitic acid, hard acid At least one of fatty acids and salts thereof; the hydroxycarboxylic acids are selected from citric acid, tartaric acid, malic acid, gluconic acid, glucoheptonic acid, glycolic acid, lactic acid, trihydroxybutyric acid, ascorbic acid, iso At least one of citric acid, hydroxymalonic acid, glyceric acid, hydroxybutyric acid, leucine, citracallic acid, and their salts; the amino carboxylic acids are selected from hydroxyethyl ethylenediamine triacetic acid, di Ethylenetriaminepentaacetic acid, triethylenetetraminehexaacetic acid, ethylenediaminetetraacetic acid, ethylenediaminetetrapropionic acid, ammoniatriacetic acid, iminodiacetic acid, hydroxyethyliminodiacetic acid, iminodipropylene Acid, 1,3-propanediaminetetraacetic acid, 1,3-diamino-2-hydroxypropanetetraacetic acid, glycol ether diaminetetraacetic acid, m-phenylenediaminetetraacetic acid, 1,2-cyclohexanediamine -N,N,N′,N′-tetraacetic acid, diaminopropionic acid, glutamic acid, dicarboxymethylglutamic acid, ornithine, cysteine, N,N-bis(2-hydroxyethyl At least one of glutamate, (S,S)-ethylenediamine succinic acid, and salts thereof; the polycarboxylic acids are selected from succinic acid, glutaric acid, malonic acid, adipic acid, At least one of oxalic acid, maleic acid, citraconic acid, itaconic acid, mesaconic acid, and salts thereof. A method of electroless copper plating, characterized in that it includes: (a) an adsorption promotion step (pretreatment step), immersing a non-conductive substrate in a liquid containing an adsorption promoter, the adsorption promoter selected from nonionic surface active At least one of an agent, a cationic surfactant, an anionic surfactant, and an amphoteric surfactant; (b) a catalyst-imparting step of immersing the non-conductive substrate in any one of claims 1 to 5 In the copper colloidal catalytic solution, the copper colloidal particles are adsorbed on the surface of the substrate; and (c) an electroless plating step, using an electroless copper plating solution to form a copper coating on the substrate subjected to the adsorption treatment. The method for electroless copper plating according to claim 6, wherein the adsorption accelerator in the step (a) is a cationic surfactant and/or an amphoteric surfactant. A copper-coated non-conductive substrate is formed by the electroless copper plating method described in claim 6 or 7.