JP6145681B2 - Aqueous copper colloid catalyst solution for electroless copper plating and electroless copper plating method - Google Patents

Description

  The present invention relates to an aqueous copper colloidal catalyst solution for applying a catalyst as a pretreatment when electroless copper plating is applied to a non-conductive substrate, and the electroless copper plating method. It is possible to provide a copper film having a good uniformity and a uniform appearance.

  Starting with copper or copper alloy substrates, especially glass / epoxy resins, glass / polyimide resins, epoxy resins, polyimide resins, polycarbonate resins, ABS resins, PET resins and other resin substrates, glass substrates, ceramic substrates, etc. In order to perform electroless copper plating on a non-conductive substrate, first, a noble metal such as palladium, silver, or platinum is adsorbed on the substrate and used as a catalyst nucleus, and then electroless copper is passed through the catalyst nucleus. In general, a copper film is deposited on a substrate by a plating solution.

On the other hand, there is also a catalyst application method that uses a specific metal such as copper, nickel, cobalt, etc., which is inexpensive, without using a precious metal catalyst. In the catalyst solution of the specific metal, a soluble metal salt is treated with a reducing agent to form a metal. The basic principle is to produce colloidal particles of this and use them as catalyst nuclei.
Among these, the prior art of the aqueous copper colloid catalyst solution is as follows.

(1) Patent Document 1
A soluble copper salt, a dispersant, and a complexing agent are added, and after reducing with a reducing agent, a stabilizer is added to produce a fine copper catalyst solution for electroless copper plating.
The dispersant is gelatin or a nonionic surfactant, the complexing agent is dicarboxylic acid, oxycarboxylic acid or the like, and the reducing agent is sodium borohydride, dimethylamine borane or the like. Stabilizers include sodium hypophosphite and dimethylamine borane.
In Example 4 (upper left column on page 4), an object to be plated was immersed in a catalyst solution containing copper sulfate, gelatin, sodium borohydride, and hypophosphite, and then electroless copper plating was performed. Yes.

(2) Patent Document 2
An electroless plating catalyst comprising a copper salt, an anionic surfactant, and a reducing agent is applied to an object to be plated, and after electroless copper plating, electrolytic copper plating is performed (claims 1 and 2, paragraph 42). .
In Production Example 2 (paragraph 52), which is a specific example of the copper catalyst solution, the catalyst solution contains a copper ammine complex of copper sulfate and ammonia, an anionic surfactant, and sodium borohydride (reducing agent).

(3) Patent Document 3
After applying a catalyst with a copper (I) oxide colloidal catalyst solution to a substrate, copper is directly plated on the substrate by immersion in a solution containing a copper salt, a reducing agent, and a complexing agent. The solution contains a complexing agent and a reducing agent, but the composition of the catalyst solution is unknown.

(4) Patent Document 4
A method for preparing a catalyst solution containing cuprous salt, hypophosphite and chloride ions (Claim 1), or further containing an organic or inorganic reducing agent (amine boranes, borohydride compounds, formic acid, etc.) (Claim) Items 1 to 3), and the object to be plated are pretreated with a conditioning agent containing a surfactant (cationic, anionic, amphoteric, nonionic; paragraph 56), catalyzed with a catalyst solution, and electroless plating is performed. A method (claims 8-9) is disclosed.
The types of electroless plating are copper, nickel, gold, etc., and electroless copper plating is preferred (paragraph 70).
In the conditioning agent, particularly when a cationic surfactant is used, the hydrophilic group of the surfactant adsorbed on the object to be plated is negatively charged, the first copper ion is easily adsorbed, and the copper is uniformly distributed. It is described that a catalyzed plating object on which ions are adsorbed is obtained (paragraph 58).

(5) Patent Document 5
Treating the non-conductive substrate with an activator solution comprising a noble metal / metal-colloid (eg palladium / tin colloidal solution), and then a metal salt solution such as a copper salt and a complexing agent and reducing agent of the metal ion A direct metallization method of a non-conductive substrate is described (paragraphs 1 and 13), in which electroless plating and electroplating are performed after contact with a conductive solution containing.
The metal salt of the conductor solution is reduced with the metal of the activator solution. For example, divalent tin (oxidizing cation) of the activator solution acts on the divalent copper ion (reducing cation) of the conductor solution. As tin oxidizes to tetravalent, divalent copper ions are reduced to metallic copper (paragraphs 24 and 29).
In Example 1, after activation treatment of an ABS plastic substrate with an activator dispersion containing a palladium-tin colloid, tartaric acid (complexing agent) and hypophosphite (or hypophosphite and hydroxy) Treatment with a conductor solution containing methyl sulfonate (reducing agent), copper salt, lithium salt, and the like is described (Table 1 in paragraphs 65 and 66).

Japanese Patent Laid-Open No. 2-093076 Japanese Patent Laid-Open No. 10-229280 Japanese Patent Laid-Open No. 7-197266 JP2011-225929A Special table 2013-522476 gazette

However, the above-mentioned aqueous catalyst solution is based on the basic principle of producing a fine metal particle by treating a soluble metal salt with a reducing agent. However, there is a problem in stability over time including the catalyst solution of the above-mentioned patent document. There are many things, and there is a situation that it is not easy to ensure the continuity of work of applying a catalyst and electroless plating smoothly for a long time.
In addition, even after electroless plating after applying a catalyst to a non-conductive substrate with a copper catalyst solution, deposition is difficult, plating defects that do not partially deposit on the film, or uneven plating occurs. Or inferior uniformity.

  An object of the present invention is to improve the temporal stability of a water-based copper catalyst solution and to perform electroless copper plating on a non-conductive substrate provided with a catalyst to obtain a uniform and non-uniform copper film.

The inventors of the present invention, for example, use a stabilizer in order to maintain the reduced state of copper in Patent Document 1, and therefore, first, a component having a complexing function with respect to the copper salt is contained in the catalyst solution. The idea was to stabilize colloidal particles.
And while containing colloidal stabilizers such as oxycarboxylic acids and aminocarboxylic acids that stabilize the copper salt in the copper catalyst solution, it is possible to improve the temporal stability by adjusting the mixing ratio of the copper salt and the stabilizer, The presence of the surfactant has an adverse effect on the stability over time, and even if it is added, its content should be kept to a very small amount, and the presence of the predetermined water-soluble polymer greatly contributes to the stability over time. I got the knowledge.
Furthermore, based on this knowledge, if the pretreatment of immersing the substrate in a liquid containing an adsorption accelerator made of a surfactant before applying the catalyst with the copper catalyst solution is performed weightwise, the catalyst activity is increased when applying the catalyst. The present invention has been completed by newly finding out that it is excellent in the uniformity of the deposited film obtained by electroless copper plating and the prevention of uneven appearance of the film.

That is, the present invention 1 is an aqueous copper colloid catalyst solution for applying a catalyst by bringing it into contact with a non-conductive substrate on which electroless copper plating is performed.
(A) a soluble copper salt;
(B) a reducing agent;
(C) at least one colloidal stabilizer selected from the group consisting of oxycarboxylic acids , aminocarboxylic acids, and polycarboxylic acids ,
The content molar ratio of the components (A) and (C) is A: C = 1: 0.03 to 1:35 , the content of the component (A) is 0.05 to 0.5 mol / L, and the components The content molar ratio of (A) and (B) is A: B = 1: 0.1 to 1: 5,
It contains no surfactant or the surfactant content is 950 mg / L or less ,
An aqueous copper colloid catalyst solution for electroless copper plating , having a pH of 1 to 6 or 8 to 12 and a copper colloid having an average particle diameter of 1 to 250 nm .

Invention 2 is the invention 1, wherein the reducing agent (B) is a borohydride compound, amine boranes, hypophosphorous acids, aldehydes, ascorbic acids, hydrazines, polyhydric phenols, polyhydric naphthols, An aqueous copper colloidal catalyst solution for electroless copper plating, which is at least one selected from the group consisting of phenolsulfonic acids, naphtholsulfonic acids, and sulfinic acids.

Invention 3 is the invention 1 or 2, wherein the oxycarboxylic acids (C) are citric acid, tartaric acid, malic acid, gluconic acid, golcoheptonic acid, glycolic acid, lactic acid, trioxybutyric acid, isocitric acid, tartronic acid, glycerin. An aqueous copper colloidal catalyst solution for electroless copper plating, which is at least one selected from the group consisting of acids, hydroxybutyric acid, leucine acid, citramalic acid, and salts thereof.

Invention 4 relates to any one of Inventions 1 to 3 , wherein the aminocarboxylic acid (C) is hydroxyethylethylenediaminetriacetic acid, diethylenetriaminepentaacetic acid, triethylenetetraminehexaacetic acid, ethylenediaminetetraacetic acid, ethylenediaminetetrapropionic acid, nitrilo Triacetic acid, iminodiacetic acid, hydroxyethyliminodiacetic acid, iminodipropionic acid, 1,3-propanediaminetetraacetic acid, 1,3-diamino-2-hydroxypropanetetraacetic acid, glycol etherdiaminetetraacetic acid, metaphenylenediaminetetraacetic acid 1,2-diaminocyclohexane-N, N, N ′, N′-tetraacetic acid, diaminopropionic acid, glutamic acid, dicarboxymethylglutamic acid, ornithine, cysteine, N, N-bis (2-hydroxyethyl) glycine, ( S, S) -ethylenedia An aqueous copper colloid catalyst solution for electroless copper plating, characterized in that at least one selected from Nkohaku acids and the group consisting of salts thereof.

Invention 5 is as described in any one of Inventions 1 to 4 , wherein the polycarboxylic acid (C) is succinic acid, glutaric acid, malonic acid, adipic acid, oxalic acid, maleic acid, citraconic acid, itaconic acid, mesaconic acid And an aqueous copper colloid catalyst solution for electroless copper plating, which is at least one selected from the group consisting of these salts.

The present invention 6 is (a) non-conductive to at least one liquid containing an adsorption accelerator selected from the group consisting of a nonionic surfactant, a cationic surfactant, an anionic surfactant, and an amphoteric surfactant. Adsorption promotion process (pretreatment process) for immersing the substrate;
(B) a catalyst application step of immersing a non-conductive substrate in the aqueous copper colloid catalyst solution of any one of the present inventions 1 to 5 to adsorb copper colloid particles on the substrate surface;
(C) an electroless plating step of forming a copper film using an electroless copper plating solution on the adsorption-treated substrate.

The present invention 7 is the electroless copper plating method according to the present invention 6, wherein the adsorption accelerator in the step (a) is a cationic surfactant and / or an amphoteric surfactant.

The copper colloid catalyst solution of the present invention contains a colloidal stabilizer that has a complexing action on the copper salt, specifies the ratio of the stabilizer and the copper salt, and does not contain a surfactant or contains only a small amount. By not doing so, the stability over time of the liquid can be significantly improved.
Incidentally, the metal body-containing liquid (that is, the catalyst liquid) of Patent Document 1 does not contain a component that causes a complexing action of a copper salt. In addition, the catalyst solution of Example 4 of Patent Document 1 (upper left column to upper right column on page 4) contains 1000 mg / L of gelatin as a dispersant, or Production Example 2 of Patent Document 2 (paragraph 52). This catalyst solution contains 1000 mg / L of an anionic surfactant, and both exceed the upper limit of the specified amount of the surfactant in the catalyst solution of the present invention 1.

  In the present invention, the basic principle is to apply electroless copper plating after applying the copper colloid catalyst to the non-conductive substrate. As a pretreatment or pretreatment for applying the catalyst, the non-conductive substrate is used as an interface. By weighting the adsorption promotion treatment immersed in the liquid containing the activator and sequentially performing the adsorption promotion process, the catalyst application process, and the electroless copper plating process, the catalyst activity at the time of catalyst application is enhanced by electroless plating. The uniformity of the deposited copper film can be improved and unevenness of the film can be prevented well.

The present invention is, firstly, an aqueous copper colloid catalyst solution for bringing a catalyst into contact with a non-conductive substrate, comprising (A) a soluble copper salt, (B) a reducing agent, and (C) a colloid stabilizer. consists of a, the molar ratio of the above components (a) and (C), the content of the component (a), and specifying the molar ratio, and the pH of the components (a) and (B), surfactant Is an aqueous copper colloid catalyst solution for electroless copper plating containing no or a very small amount, and secondly, an electroless copper plating method using the first catalyst solution , which is non-conductive in advance. In this method, the substrate is subjected to adsorption promotion treatment with a surfactant-containing liquid and then subjected to electroless copper plating after the catalyst is applied with the catalyst liquid.
Examples of the non-conductive substrate include glass substrates, ceramic substrates, and the like including resin substrates such as glass / epoxy resin, glass / polyimide resin, epoxy resin, polyimide resin, polycarbonate resin, ABS resin, and PET resin.

The basic composition of the aqueous copper colloid catalyst solution of the first invention comprises (A) a soluble copper salt, (B) a reducing agent, and (C) a colloid stabilizer .
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. Specifically, copper sulfate, copper oxide, copper chloride, copper pyrophosphate, copper carbonate, or carboxylic acid copper salts such as copper acetate, copper oxalate and copper citrate, or copper methanesulfonate and copper hydroxyethanesulfonate And the like, and copper sulfate, copper citrate, and copper methanesulfonate are preferable.

  Examples of the reducing agent (B) include borohydride compounds, amine boranes, hypophosphorous acids, aldehydes, ascorbic acids, hydrazines, polyhydric phenols, polyhydric naphthols, phenolsulfonic acids, naphtholsulfonic acids, sulfines. Examples include acids. Aldehydes are formaldehyde, glyoxylic acid or salts thereof, polyhydric phenols are catechol, hydroquinone, resorcin, pyrogallol, phloroglucin, gallic acid, etc., phenol sulfonic acids are phenol sulfonic acid, cresol sulfonic acid or salts thereof, etc. It is.

The colloid stabilizer (C) is a compound that forms a copper complex in the plating bath, and fulfills the function of ensuring the temporal stability of the catalyst solution.
The colloid stabilizer (C) is selected from the group consisting of monocarboxylic acids, oxycarboxylic 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 oxycarboxylic acids include citric acid, tartaric acid, malic acid, gluconic acid, golcoheptonic acid, glycolic acid, lactic acid, trioxybutyric acid, ascorbic acid, isocitric acid, tartronic acid, glyceric acid, hydroxybutyric acid, leucine acid, citramalic acid, And salts thereof.

  Examples of the aminocarboxylic acids include ethylenediaminetetraacetic acid (EDTA), hydroxyethylethylenediaminetriacetic acid (HEDTA), diethylenetriaminepentaacetic acid (DTPA), triethylenetetraminehexaacetic acid (TTHA), ethylenediaminetetrapropionic acid, nitrilotriacetic acid (NTA). , Iminodiacetic acid (IDA), iminodipropionic acid (IDP), hydroxyethyliminodiacetic acid, 1,3-propanediaminetetraacetic acid, 1,3-diamino-2-hydroxypropanetetraacetic acid, glycol etherdiaminetetraacetic acid, meta Phenylenediaminetetraacetic acid, 1,2-diaminocyclohexane-N, N, N ′, N′-tetraacetic acid, diaminopropionic acid, glutamic acid, dicarboxymethylglutamic acid, ornithine, cysteine, N, N-bis (2-hydroxyethyl) )glycine,( , S) - ethylenediamine succinic acid and salts thereof.

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

Since the copper colloid catalyst solution of the present invention is aqueous, the solvent of the solution is limited to water and / or hydrophilic alcohol, and the use of organic solvents (including lipophilic alcohol) alone is excluded.
Moreover, about the said catalyst liquid, since catalyst activity tends to fall near neutrality, the pH of the liquid is preferably the acidic side or the alkaline side excluding the neutral range, and specifically, pH 1 to 6 and 8 to 12 are suitable. The pH is preferably 2 to 5 and 8 to 11.

In the aqueous copper colloid catalyst solution, the soluble copper salt (A) can be used alone or in combination, and its content is 0.05 to 0.5 mol / L, preferably 0.04 to 0.2 mol / L. .
The reducing agent (B) can be used alone or in combination, and its content is 0.005 to 1 mol / L, preferably 0.05 to 0.5 mol / L. If the content of the reducing agent is less than the appropriate amount, the reducing action of the copper salt is lowered. Conversely, if the content is too large, the homogeneity of the copper film deposited by electroless plating may be lowered.
The colloid stabilizer (C) can be used alone or in combination, and its content is 0.005 to 2 mol / L, preferably 0.05 to 1.5 mol / L.
In the aqueous colloidal catalyst solution, the molar ratio of (A) to (C) is A: C = 1: 0.03 to 1:35, preferably A: C = 1: 0.5 to 1. : 24. If the relative content of the colloidal stabilizer (C) is too small, the stability with time of the catalyst solution is lowered, and as a result, the copper film obtained by electroless plating causes a deposition failure. On the other hand, even if the content of the colloid stabilizer (C) is too large, the stability of the catalyst solution over time is impaired, and the quality of the obtained copper film is lowered (see the test examples described later).
In the aqueous colloidal catalyst solution, the molar ratio of (A) to (B) is A: B = 1: 0.1 to 1: 5.
In the preparation of the catalyst solution, in order to smoothly donate electrons from the reducing agent to the copper ions, the reducing agent solution is slowly dropped over the solution containing the soluble copper salt (and colloid stabilizer) over time. Basically to do. For example, a reducing agent solution of 5 to 50 ° C. (preferably 10 to 40 ° C.) is dropped into a copper salt solution and stirred for 20 to 1200 minutes (preferably 30 to 300 minutes) to prepare a catalyst solution. It should be noted that the preparation of the catalyst solution does not exclude dropping the soluble copper salt solution into the reducing agent solution.
In the catalyst solution of the present invention, the copper colloid particles generated from the soluble copper salt by the action of the reducing agent are fine particles having a suitable average particle diameter of 1 to 250 nm, preferably 1 to 120 nm, more preferably 1 to 100 nm.
When the average particle size of the copper colloidal particles is 250 nm or less, when the non-conductive substrate is immersed in the catalyst solution, the colloidal particles enter into the dents on the fine uneven surface of the substrate, and are closely adsorbed or caught. It can be presumed that the application of copper colloid nuclei to the substrate surface is accelerated by Conversely, when the average particle size is larger than 250 nm, it is difficult to obtain a stable copper colloid due to agglomeration, precipitation, or separation, and the anchor effect cannot be expected. Therefore, the copper colloid particles can only be partially applied to the substrate surface. There is a risk that it may not be applied or it may become defective.

In the aqueous copper colloid catalyst solution of the present invention 1, it is necessary not to contain a surfactant or to suppress the content of the surfactant to 950 mg / L or less.
If a surfactant is contained in the catalyst solution, the catalyst activity may decrease, and it is preferable not to add a surfactant. However, in the case of a very small content of 950 mg / L or less, there is not much adverse effect on the decrease in catalyst activity, and preferably 700 mg / L or less.
The above-mentioned surfactant means various nonionic, amphoteric, cationic, or anionic surfactants. In particular, amphoteric, cationic, anionic, or low-molecular nonionic surfactants are not preferable.
Nonionic surfactants include C1-C20 alkanols, phenols, naphthols, bisphenols, (poly) C1-C25 alkylphenols, (poly) arylalkylphenols, C1-C25 alkylnaphthols, C1-C25 alkoxylated phosphoric acids (salts). ), Sorbitan esters, polyalkylene glycols, C1 to C22 aliphatic amines, C1 to C22 aliphatic amides and the like obtained by addition condensation of 2-300 moles of ethylene oxide (EO) and / or propylene oxide (PO), And C25 alkoxylated phosphoric acid (salt).
Examples of the cationic surfactant include quaternary ammonium salts, pyridinium salts, and the like. Specific examples include lauryl trimethyl ammonium salt, stearyl trimethyl ammonium salt, lauryl dimethyl ethyl ammonium salt, octadecyl dimethyl ethyl ammonium salt. Dimethylbenzyl lauryl ammonium salt, cetyl 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, hexadecyl pyridinium salt, lauryl pyridinium salt, dodecyl Pyridinium salt, stearylamine acetate, laurylamine acetate, octadecylamine acetate Such as the Tate, and the like.
Examples of the anionic surfactant include alkyl sulfates, polyoxyethylene alkyl ether sulfates, polyoxyethylene alkyl phenyl ether sulfates, alkyl benzene sulfonates, {(mono, di, tri) alkyl} naphthalene sulfonates, etc. Is mentioned. Examples of the amphoteric surfactant include carboxybetaine, imidazoline betaine, sulfobetaine, and aminocarboxylic acid. In addition, sulfation of a condensation product of ethylene oxide and / or propylene oxide and an alkylamine or diamine, or a sulfonated adduct can also be used.

An object of the present invention is to improve the temporal stability of the aqueous copper catalyst solution and to form a uniform and non-uniform film when electroless copper plating is applied to a non-conductive substrate. In the catalyst solution, the inclusion of a synthetic water-soluble polymer instead of eliminating the surfactant or suppressing it to below a predetermined amount improves the dispersibility of the colloidal particles, which is excellent for electroless copper plating. It can contribute to the deposition of a uniform and uniform copper film.
The above synthetic water-soluble polymer means to exclude naturally derived water-soluble polymers such as gelatin and starch .
The synthetic water-soluble polymer may be partially overlapped with the component to which it belongs in relation to the surfactant that is subject to exclusion or suppression of the catalyst solution of the present invention 1. Both are different concepts.
In the case of containing this synthetic water-soluble polymer, for example, it may or may not be contained regardless of the presence or absence of a surfactant. It is preferable that no activator is contained.
Examples of the water-soluble polymer of the synthetic system include polyethylene glycol (PEG) , polypropylene glycol (PPG), polyvinyl pyrrolidone (PVP), polyvinyl alcohol (PVA), polyacrylamide (PAM), polyethylene imine (PEI), and polyacrylate. In particular, high molecular weight PEG, PVP, PVA and the like are preferable.
The synthetic water-soluble polymer can be used singly or in combination, and its content relative to the catalyst solution is 0.05 to 100 g / L, preferably 0.5 to 50 g / L, more preferably 1.0 to 30 g / L. It is.

The present invention 6 is an electroless plating method using the aqueous copper colloid catalyst solution, which is formed by sequentially combining the following three steps.
(A) Adsorption promotion step (b) Catalyst application step (c) Electroless copper plating step The adsorption promotion step (a) is, in other words, a pretreatment (pretreatment) step of catalyst application of (b), and is a nonionic surfactant. This is a step of immersing a non-conductive substrate in a liquid containing at least one adsorption accelerator selected from the group consisting of an agent, a cationic surfactant, an anionic surfactant, and an amphoteric surfactant. By bringing into contact with the liquid containing the agent, the wettability of the substrate surface is increased to enhance the catalytic activity, and the adsorption of the copper colloid particles in the next step is promoted.
In the adsorption promotion step, it is necessary to bring the non-conductive substrate into contact with the surfactant-containing liquid, so it is basically immersed in the liquid, but the containing liquid is sprayed on the substrate or applied with a brush. There is no problem.
As shown in the present invention 7 , from the viewpoint of promoting adsorption, a positively charged cationic or amphoteric surfactant is preferred, and a cationic surfactant is particularly preferred. Further, when a small amount of nonionic surfactant is used in combination with the cationic surfactant, the adsorption promoting effect is further increased.
In the catalyst solution of the present invention 1 , since the colloidal copper particles produced by allowing a reducing agent to act on a soluble copper salt have a negative zeta potential, for example, when a non-conductive substrate is contact-treated with a cationic surfactant, the substrate becomes It is easy to carry a positive charge, and the adsorption efficiency of the copper colloidal particles on the substrate in the next process is increased.
Specific examples of the surfactant are as described for the surfactant described as an object to be excluded or suppressed in the catalyst solution of the first invention.
The content of the surfactant is from 0.05 to 100 g / L, preferably from 0.5 to 50 g / L. The temperature of the surfactant-containing liquid is preferably about 15 to 70 ° C., and the immersion time is preferably about 0.5 to 20 minutes.

The non-conductive substrate that has finished the adsorption promoting process is washed with pure water and then dried or transferred to the next catalyst application step (b) without drying.
In the catalyst application step, the non-conductive substrate is immersed in the aqueous copper colloid catalyst solution to adsorb the copper colloid on the substrate surface.
The liquid temperature of the catalyst solution is 10 to 70 ° C., and the immersion time is about 0.1 to 20 minutes. In the immersion treatment, it is sufficient to immerse the substrate in the catalyst solution in a stationary state. You may move.

The nonconductive substrate immersed in the catalyst solution is washed with pure water and then dried or transferred to the electroless copper plating step (c) without drying.
The electroless copper plating may be processed in the same manner as in the past, 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.
The soluble copper salt is as described in the copper colloid catalyst solution.

  The reducing agent contained in the electroless copper plating solution is also as described in the copper colloid catalyst solution, including formaldehyde (formalin water), hypophosphorous acid, phosphorous acid, amine borane, borohydride. And glyoxylic acid, and formalin water is preferred.

  The complexing agent contained in the electroless copper plating solution has a part in common with the colloidal stabilizer described in the copper colloid catalyst solution, specifically, ethylenediaminetetraacetic acid (EDTA), diethylenetriaminepentaacetic acid (DTPA). ), Aminocarboxylic acids such as triethylenetetramine hexaacetic acid (TTHA), hydroxyethylethylenediamine triacetic acid (HEDTA), nitrilotriacetic acid (NTA), iminodiacetic acid (IDA), ethylenediamine, tetramethylenediamine, hexamethylenediamine, diethylenetriamine, Polyamines such as tetraethylenepentamine and pentaethylenehexamine, aminoalcohols such as monoethanolamine, diethanolamine and triethanolamine, oxycarbons such as citric acid, tartaric acid, lactic acid and malic acid S, thioglycolic acid, glycine and the like.

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.

Hereinafter, the examples of the electroless copper plating method including the preparation of the adsorption promoter of the present invention, the copper colloid catalyst solution, and the electroless copper plating solution will be described, and the temporal stability test example of the copper colloid catalyst solution, Examples of appearance evaluation tests of the deposited copper film obtained in the above examples will be sequentially described.
The present invention is not limited to the following 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 >>
Of the following Examples 1 to 10 , Example 5 is an example containing a very small amount of surfactant in the copper colloid catalyst solution, Examples 1 to 4 and Examples 6 to 10 do not contain a surfactant in the catalyst solution. It is an example. Reference Examples 1 to 8 are examples in which the catalyst solution contains a synthetic water-soluble polymer.
Example 1 is an example in which citric acid was used as the colloid stabilizer in the catalyst solution and sodium borohydride was used as the reducing agent. Hereinafter, based on Example 1, Example 2 is an example in which the content of colloidal stabilizer is reduced, Example 3 is an example in which the content of colloidal stabilizer is increased, and Example 4 is in which the content of reducing agent is reduced. Example 6 is an example in which the type and content of the colloidal stabilizer are changed, and Example 7 is an example in which the type of the reducing agent and the liquid temperature of the catalyst solution are changed. Moreover, based on Example 7 , Examples 8-10 are examples which changed soluble copper salt.
As described above, Example 5 is an example in which a very small amount of nonionic surfactant is contained on the basis of Example 1, and the kind of colloidal stabilizer and the pH of the catalyst solution are changed.
Based on Example 1, Reference Example 1 is an example in which polyvinyl pyrrolidone (PVP) is contained in the catalyst solution, Reference Example 2 is an example in which polyethylene glycol (PEG) is also contained, and Reference Example 3 and Reference Example 5 are PVP. Examples containing (changing the average molecular weight), Reference Example 4 is an example containing polyethyleneimine (PEI), and Reference Example 6 is an example containing polyacrylamide (PAM).
Examples 1 to 9 and Reference Examples 1 to 6 are examples where the pH of the catalyst solution is acidic, while Examples 10 and Reference Examples 7 to 8 are examples where the pH of the catalyst solution is on the alkali side. Incidentally, about 10 to 20% sulfuric acid or sodium hydroxide was used for pH adjustment.

On the other hand, among the following Comparative Examples 1 to 6, Comparative Example 1 is a blank example in which no colloidal stabilizer is contained in the catalyst solution, and Comparative Example 2 is a catalyst solution in which the relative content ratio of the colloidal stabilizer to the copper salt is the present invention 1 to 1. An example in which the content ratio is lower than the lower limit of the specified amount of 2, Comparative Example 3 is an example in which the content ratio exceeds the upper limit of the specified amount of the present invention 1-2, and Comparative Example 4 is a controlled specified amount of the present invention 1 in the catalyst solution. In Comparative Example 5, the catalyst solution contains more surfactant than Comparative Example 4, and in Comparative Example 6, the electroless plating process was immediately performed from the catalyst application process without the adsorption promotion process. This is a blank example.
Further, in Example 4 of Patent Document 1 described above , gelatin is contained as a dispersant in the catalyst solution, but Comparative Example 7 contains gelatin which is a water-soluble polymer derived from nature instead of the above-described synthetic system in the catalyst solution. In other words, this is a conforming example of Patent Document 1 above.

(1) Example 1
(A) Preparation of Adsorption Accelerator-Containing Liquid An adsorption accelerator-containing liquid was prepared with the following composition.
[Adsorption accelerator-containing liquid]
Quaternary ammonium salt of diallylamine polymer 5g / L
Polyoxyalkylene branched decyl ether 1g / L
(B) Preparation of copper colloid catalyst solution
[Copper solution]
Copper sulfate (as Cu2 +) 0.2 mol / L
Citric acid 0.6 mol / L
[Reducing agent solution]
Sodium borohydride 0.2 mol / L
A reducing agent solution was dropped into the copper solution at 25 ° C. adjusted to pH 4.0 and stirred for 45 minutes to prepare an aqueous copper colloid catalyst solution.
The molar ratio of each component of the catalyst solution is as follows.
Copper salt: colloid stabilizer = 1: 3, copper salt: reducing agent = 1: 1
The produced copper colloid particles had an average particle size of about 10 nm.
(C) Preparation of electroless copper plating solution 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 / L
Formaldehyde 5.0g / L
EDTA 30.0g / L
Sodium hydroxide 9.6g / L
Residual pure water pH (20 ° C) 12.8
(D) Processing conditions for electroless copper plating
First, a glass / epoxy resin substrate (plate thickness: 1.0 mm) which is a non-conductive substrate was used as a sample substrate.
And after carrying out adsorption promotion to a sample substrate using the adsorption promoter of the above (a), it is immersed in the catalyst solution of the above (b) to give a catalyst, and further electroless with the plating solution of the above (c). Copper plating was performed.
Specifically, the sample substrate was immersed in the adsorption accelerator-containing liquid at 50 ° C. for 2 minutes and washed with pure water. Next, the sample substrate subjected to the adsorption promotion treatment (pretreatment) was immersed in the copper colloid catalyst solution at 25 ° C. for 10 minutes and washed with pure water. Thereafter, the sample substrate to which the catalyst is applied is immersed in the electroless copper plating solution, subjected to electroless plating at 50 ° C. for 10 minutes, and a copper film is formed on the sample substrate. Washed with and dried.

(2) Example 2
Based on the above Example 1, the preparation method of the copper colloid catalyst solution and the electroless copper plating solution and the processing conditions of each step were carried out except that the adsorption accelerator containing liquid and the copper colloid catalyst liquid were prepared with the following composition. Same as Example 1.
In addition, the molar ratio of each component of the catalyst solution is as follows.
Copper salt: colloidal stabilizer = 1: 0.2, copper salt: reducing agent = 1: 1
(A) Preparation of a liquid containing an adsorption accelerator
[Adsorption accelerator-containing liquid]
Lauryldimethylbenzylammonium chloride 5g / L
(B) Preparation of copper colloid catalyst solution
[Copper solution]
Copper sulfate (as Cu2 +) 0.2 mol / L
Citric acid 0.04 mol / L
[Reducing agent solution]
Sodium borohydride 0.2 mol / L
The reducing agent solution was dropped into a copper solution at 25 ° C. adjusted to pH 4.0 and stirred for 45 minutes.
The average particle diameter of the produced copper colloid particles was about 15 nm.

(3) Example 3
Based on the above Example 1, the preparation method of the copper colloid catalyst solution and the electroless copper plating solution and the processing conditions of each step were carried out except that the adsorption accelerator containing liquid and the copper colloid catalyst liquid were prepared with the following composition. Same as Example 1.
In addition, the molar ratio of each component of the catalyst solution is as follows.
Copper salt: colloid stabilizer = 1: 15, copper salt: reducing agent = 1: 1
(A) Preparation of a liquid containing an adsorption accelerator
[Adsorption accelerator-containing liquid]
Lauryldimethylaminoacetic acid betaine 5g / L
(B) Preparation of copper colloid catalyst solution
[Copper solution]
Copper sulfate (as Cu2 +) 0.2 mol / L
Citric acid 3.0 mol / L
[Reducing agent solution]
Sodium borohydride 0.2 mol / L
The reducing agent solution was dropped into a copper solution at 25 ° C. adjusted to pH 4.0 and stirred for 45 minutes.
The produced copper colloid particles had an average particle size of about 12 nm.

(4) Example 4
Based on the above Example 1, the preparation method of the copper colloid catalyst solution and the electroless copper plating solution and the processing conditions of each step were carried out except that the adsorption accelerator containing liquid and the copper colloid catalyst liquid were prepared with the following composition. Same as Example 1.
In addition, the molar ratio of each component of the catalyst solution is as follows.
Copper salt: colloidal stabilizer = 1: 4, copper salt: reducing agent = 1: 0.05
(A) Preparation of a liquid containing an adsorption accelerator
[Adsorption accelerator-containing liquid]
Quaternary ammonium salt of diallylamine polymer 5g / L
Polyoxyalkylene branched decyl ether 1g / L
(B) Preparation of copper colloid catalyst solution
[Copper solution]
Copper sulfate (as Cu2 +) 0.2 mol / L
Citric acid 0.8 mol / L
[Reducing agent solution]
Sodium borohydride 0.01 mol / L
The reducing agent solution was dropped into a copper solution at 25 ° C. adjusted to pH 4.0 and stirred for 45 minutes.
The produced copper colloid particles had an average particle size of about 25 nm.

(5) Example 5
A preparation method of a copper colloid catalyst solution (excluding pH conditions) and an electroless copper plating solution, except that the adsorption accelerator containing solution and the copper colloid catalyst solution were prepared with the following composition on the basis of Example 1 above. The processing conditions for each step were the same as those in Example 1.
In addition, the ratio of each component of the said catalyst liquid is as follows.
Copper salt: colloidal stabilizer = 1: 3.5, copper salt: reducing agent = 1: 1
(A) Preparation of a liquid containing an adsorption accelerator
[Adsorption accelerator-containing liquid]
Lauryldimethylaminoacetic acid betaine 5g / L
(B) Preparation of copper colloid catalyst solution
[Copper solution]
Copper sulfate (as Cu2 +) 0.2 mol / L
Gluconic acid 0.7 mol / L
Polyoxyethylene
-Styrenated phenyl ether (EO10 mol) 0.2g / L
[Reducing agent solution]
Sodium borohydride 0.2 mol / L
The reducing agent solution was added dropwise to a 25 ° C. copper solution adjusted to pH 3.0 and stirred for 45 minutes.
The average particle diameter of the produced copper colloidal particles was about 17 nm.

(6) Example 6
A preparation method of a copper colloid catalyst solution (except for stirring conditions) and an electroless copper plating solution, except that the adsorption accelerator containing solution and the copper colloid catalyst solution were prepared with the following composition on the basis of Example 1 above. The processing conditions for each step were the same as those in Example 1.
In addition, the molar ratio of each component of the catalyst solution is as follows.
Copper salt: colloid stabilizer = 1: 3, copper salt: reducing agent = 1: 1
(A) Preparation of a liquid containing an adsorption accelerator
[Adsorption accelerator-containing liquid]
Lauryldimethylbenzylammonium chloride 5g / L
(B) Preparation of copper colloid catalyst solution
[Copper solution]
Copper sulfate (as Cu2 +) 0.2 mol / L
Glycolic acid 0.6 mol / L
[Reducing agent solution]
Sodium borohydride 0.2 mol / L
The reducing agent solution was dropped into a copper solution at 25 ° C. adjusted to pH 4.0 and stirred for 90 minutes.
The average particle diameter of the produced copper colloid particles was about 15 nm.

(7) Example 7
Based on Example 1 above, a copper colloid catalyst solution (except for pH and temperature conditions of the copper solution) and electroless, except that the liquid containing the adsorption accelerator and the copper colloid catalyst solution were prepared with the following composition: The method for preparing the copper plating solution and the processing conditions for each step were the same as in Example 1.
In addition, the molar ratio of each component of the catalyst solution is as follows.
Copper salt: colloidal stabilizer = 1: 4, copper salt: reducing agent = 1: 0.5
(A) Preparation of a liquid containing an adsorption accelerator
[Adsorption accelerator-containing liquid]
Lauryldimethylbenzylammonium chloride 5g / L
(B) Preparation of copper colloid catalyst solution
[Copper solution]
Copper methanesulfonate (as Cu2 +) 0.2 mol / L
Citric acid 0.8 mol / L
[Reducing agent solution]
Dimethylamine borane 0.1 mol / L
The reducing agent solution was added dropwise to a 35 ° C. copper solution adjusted to pH 3.0 and stirred for 45 minutes.
The produced copper colloid particles had an average particle size of about 16 nm.

(8) Example 8
Based on Example 1 above, a copper colloid catalyst solution (except for pH and temperature conditions of the copper solution) and electroless, except that the liquid containing the adsorption accelerator and the copper colloid catalyst solution were prepared with the following composition: The method for preparing the copper plating solution and the processing conditions for each step were the same as in Example 1.
In addition, the molar ratio of each component of the catalyst solution is as follows.
Copper salt: colloid stabilizer = 1: 3.5, copper salt: reducing agent = 1: 0.75
(A) Preparation of a liquid containing an adsorption accelerator
[Adsorption accelerator-containing liquid]
Quaternary ammonium salt of diallylamine polymer 5g / L
(B) Preparation of copper colloid catalyst solution
[Copper solution]
Copper citrate 2.5 hydrate (as Cu2 +) 0.2 mol / L
Citric acid 0.7 mol / L
[Reducing agent solution]
Dimethylamine borane 0.15 mol / L
The reducing agent solution was added dropwise to a 35 ° C. copper solution adjusted to pH 5.0 and stirred for 45 minutes.
The average particle diameter of the produced copper colloidal particles was about 14 nm.

(9) Example 9
Based on Example 1 above, the copper colloid catalyst solution (except for the temperature condition of the copper solution) or electroless copper plating, except that the liquid containing the adsorption accelerator and the copper colloid catalyst solution were prepared with the following composition: The liquid preparation method and the treatment conditions for each step were the same as in Example 1.
In addition, the molar ratio of each component of the catalyst solution is as follows.
Copper salt: colloid stabilizer = 1: 2, copper salt: reducing agent = 1: 0.5
(A) Preparation of a liquid containing an adsorption accelerator
[Adsorption accelerator-containing liquid]
Lauryldimethylaminoacetic acid betaine 5g / L
(B) Preparation of copper colloid catalyst solution
[Copper solution]
Copper sulfate (as Cu2 +) 0.2 mol / L
Gluconic acid 0.4 mol / L
[Reducing agent solution]
Dimethylamine borane 0.1 mol / L
The reducing agent solution was added dropwise to a 35 ° C. copper solution adjusted to pH 4.0 and stirred for 45 minutes.
The produced copper colloid particles had an average particle size of about 20 nm.

(10) Example 10
A preparation method of a copper colloid catalyst solution (excluding pH conditions) and an electroless copper plating solution, except that the adsorption accelerator containing solution and the copper colloid catalyst solution were prepared with the following composition on the basis of Example 1 above. The processing conditions for each step were the same as those in Example 1.
In addition, the molar ratio of each component of the catalyst solution is as follows.
Copper salt: colloidal stabilizer = 1: 3, copper salt: reducing agent = 1: 0.5
(A) Preparation of a liquid containing an adsorption accelerator
[Adsorption accelerator-containing liquid]
Quaternary ammonium salt of diallylamine polymer 5g / L
(B) Preparation of copper colloid catalyst solution
[Copper solution]
Copper sulfate (as Cu2 +) 0.2 mol / L
Diethylenetriaminepentaacetic acid 0.6 mol / L
[Reducing agent solution]
Sodium borohydride 0.1 mol / L
The reducing agent solution was added dropwise to a 25 ° C. copper solution adjusted to pH 10.0 and stirred for 45 minutes.
The produced copper colloid particles had an average particle size of about 20 nm.

(11) Reference example 1
Based on the above Example 1, the preparation method of the copper colloid catalyst solution and the electroless copper plating solution and the processing conditions of each step were carried out except that the adsorption accelerator containing solution and the copper colloid catalyst solution were prepared with the following composition. Same as Example 1.
In addition, the molar ratio of each component of the catalyst solution is as follows.
Copper salt: colloidal stabilizer = 1: 4, copper salt: reducing agent = 1: 2.25
(A) Preparation of a liquid containing an adsorption accelerator
[Adsorption accelerator-containing liquid]
Quaternary ammonium salt of diallylamine polymer 5g / L
(B) Preparation of copper colloid catalyst solution
[Copper solution]
Copper sulfate (as Cu2 +) 0.2 mol / L
Citric acid 0.8 mol / L
Polyvinylpyrrolidone (average molecular weight 40,000) 2.0 g / L
[Reducing agent solution]
Sodium borohydride 0.45 mol / L
The reducing agent solution was dropped into a copper solution at 25 ° C. adjusted to pH 4.0 and stirred for 45 minutes.
The average particle diameter of the produced copper colloidal particles was about 8 nm.

(12) Reference example 2
A preparation method of a copper colloid catalyst solution (excluding the stirring time) and an electroless copper plating solution, except that the adsorption accelerator containing solution and the copper colloid catalyst solution were prepared with the following composition on the basis of Example 1 above. The processing conditions for each step were the same as those in Example 1.
In addition, the molar ratio of each component of the catalyst solution is as follows.
Copper salt: colloidal stabilizer = 1: 3, copper salt: reducing agent = 1: 0.5
(A) Preparation of a liquid containing an adsorption accelerator
[Adsorption accelerator-containing liquid]
Lauryldimethylbenzylammonium chloride 5g / L
(B) Preparation of copper colloid catalyst solution
[Copper solution]
Copper sulfate (as Cu2 +) 0.2 mol / L
Citric acid 0.6 mol / L
Polyethylene glycol (average molecular weight 10,000) 1.0 g / L
[Reducing agent solution]
Sodium borohydride 0.1 mol / L
The reducing agent solution is added dropwise to a copper solution at 25 ° C. adjusted to pH 4.0 and stirred for 60 minutes.
The produced copper colloid particles had an average particle size of about 30 nm.

(13) Reference example 3
Based on Example 1 above, the copper colloid catalyst solution (except for the temperature condition of the copper solution) or electroless copper plating, except that the liquid containing the adsorption accelerator and the copper colloid catalyst solution were prepared with the following composition: The liquid preparation method and the treatment conditions for each step were the same as in Example 1.
In addition, the molar ratio of each component of the catalyst solution is as follows.
Copper salt: colloidal stabilizer = 1: 3, copper salt: reducing agent = 1: 0.5
(A) Preparation of a liquid containing an adsorption accelerator
[Adsorption accelerator-containing liquid]
Quaternary ammonium salt of diallylamine polymer 5g / L
Polyoxyalkylene branched decyl ether 1g / L
(B) Preparation of copper colloid catalyst solution
[Copper solution]
Copper sulfate (as Cu2 +) 0.2 mol / L
Citric acid 0.6 mol / L
Polyvinylpyrrolidone (Molecular weight 300,000) 1.0 g / L
[Reducing agent solution]
Dimethylamine borane 0.1 mol / L
The reducing agent solution was added dropwise to a 35 ° C. copper solution adjusted to pH 4.0 and stirred for 45 minutes.
The produced copper colloid particles had an average particle size of about 45 nm.

(14) Reference example 4
Based on the above Example 1, the preparation method of the copper colloid catalyst solution and the electroless copper plating solution and the processing conditions of each step were carried out except that the adsorption accelerator containing liquid and the copper colloid catalyst liquid were prepared with the following composition. Same as Example 1.
In addition, the molar ratio of each component of the catalyst solution is as follows.
Copper salt: colloid stabilizer = 1: 4, copper salt: reducing agent = 1: 1
(A) Preparation of a liquid containing an adsorption accelerator
[Adsorption accelerator-containing liquid]
Quaternary ammonium salt of diallylamine polymer 5g / L
(B) Preparation of copper colloid catalyst solution
[Copper solution]
Copper sulfate (as Cu2 +) 0.2 mol / L
Citric acid 0.8 mol / L
Polyethyleneimine 1.5g / L
[Reducing agent solution]
Sodium borohydride 0.2 mol / L
The reducing agent solution was dropped into a copper solution at 25 ° C. adjusted to pH 4.0 and stirred for 45 minutes.
The average particle diameter of the produced copper colloidal particles was about 17 nm.

(15) Reference example 5
Based on the above Example 1, the preparation method of the copper colloid catalyst solution and the electroless copper plating solution and the processing conditions of each step were carried out except that the adsorption accelerator containing liquid and the copper colloid catalyst liquid were prepared with the following composition. Same as Example 1.
In addition, the molar ratio of each component of the catalyst solution is as follows.
Copper salt: colloid stabilizer = 1: 4, copper salt: reducing agent = 1: 1
(A) Preparation of a liquid containing an adsorption accelerator
[Adsorption accelerator-containing liquid]
Quaternary ammonium salt of diallylamine polymer 5g / L
(B) Preparation of copper colloid catalyst solution
[Copper solution]
Copper sulfate (as Cu2 +) 0.2 mol / L
Citric acid 0.8 mol / L
Polyvinylpyrrolidone (Molecular weight 300,000) 1.0 g / L
[Reducing agent solution]
Sodium borohydride 0.2 mol / L
The reducing agent solution was dropped into a copper solution at 25 ° C. adjusted to pH 4.0 and stirred for 45 minutes.
The average particle diameter of the produced copper colloid particles was about 15 nm.

(16) Reference example 6
Based on the above Example 1, the preparation method of the copper colloid catalyst solution and the electroless copper plating solution and the processing conditions of each step were carried out except that the adsorption accelerator containing liquid and the copper colloid catalyst liquid were prepared with the following composition. Same as Example 1.
In addition, the molar ratio of each component of the catalyst solution is as follows.
Copper salt: colloid stabilizer = 1: 4, copper salt: reducing agent = 1: 1
(A) Preparation of a liquid containing an adsorption accelerator
[Adsorption accelerator-containing liquid]
Quaternary ammonium salt of diallylamine polymer 5g / L
(B) Preparation of copper colloid catalyst solution
[Copper solution]
Copper acetate monohydrate (as Cu2 +) 0.2 mol / L
Citric acid 0.8 mol / L
Polyacrylamide 0.5g / L
[Reducing agent solution]
Sodium borohydride 0.2 mol / L
The reducing agent solution was dropped into a copper solution at 25 ° C. adjusted to pH 4.0 and stirred for 45 minutes.
The average particle diameter of the produced copper colloidal particles was about 22 nm.

(17) Reference example 7
A preparation method of a copper colloid catalyst solution (excluding pH conditions) and an electroless copper plating solution, except that the adsorption accelerator containing solution and the copper colloid catalyst solution were prepared with the following composition on the basis of Example 1 above. The processing conditions for each step were the same as those in Example 1.
In addition, the molar ratio of each component of the catalyst solution is as follows.
Copper salt: colloidal stabilizer = 1: 3, copper salt: reducing agent = 1: 0.5
(A) Preparation of a liquid containing an adsorption accelerator
[Adsorption accelerator-containing liquid]
Quaternary ammonium salt of diallylamine polymer 5g / L
Polyoxyalkylene branched decyl ether 1g / L
(B) Preparation of copper colloid catalyst solution
[Copper solution]
Copper sulfate (as Cu2 +) 0.2 mol / L
Ethylenediaminetetraacetic acid 0.6 mol / L
Polyvinylpyrrolidone (Molecular weight 300,000) 1.0 g / L
[Reducing agent solution]
Sodium borohydride 0.1 mol / L
The reducing agent solution was added dropwise to a 25 ° C. copper solution adjusted to pH 9.0 and stirred for 45 minutes.
The produced copper colloid particles had an average particle size of about 18 nm.

(18) Reference example 8
A preparation method of a copper colloid catalyst solution (excluding pH conditions) and an electroless copper plating solution, except that the adsorption accelerator containing solution and the copper colloid catalyst solution were prepared with the following composition on the basis of Example 1 above. The processing conditions for each step were the same as those in Example 1.
In addition, the molar ratio of each component of the catalyst solution is as follows.
Copper salt: colloid stabilizer = 1: 4, copper salt: reducing agent = 1: 1
(A) Preparation of a liquid containing an adsorption accelerator
[Adsorption accelerator-containing liquid]
Quaternary ammonium salt of diallylamine polymer 5g / L
Polyoxyalkylene branched decyl ether 1g / L
(B) Preparation of copper colloid catalyst solution
[Copper solution]
Copper sulfate (as Cu2 +) 0.2 mol / L
Nitrilotriacetic acid 0.8 mol / L
Polyacrylamide 1.0g / L
[Reducing agent solution]
Dimethylamine borane 0.2 mol / L
The reducing agent solution was added dropwise to a 25 ° C. copper solution adjusted to pH 10.0 and stirred for 45 minutes.
The average particle diameter of the produced copper colloid particles was about 15 nm.

(19) Comparative Example 1
Based on the above Example 1, the preparation method of the copper colloid catalyst solution and the electroless copper plating solution and the processing conditions of each step were carried out except that the adsorption accelerator containing liquid and the copper colloid catalyst liquid were prepared with the following composition. Same as Example 1.
In addition, the molar ratio of each component of the catalyst solution is as follows.
Copper salt: colloidal stabilizer = 1: 0, copper salt: reducing agent = 1: 1
(A) Preparation of a liquid containing an adsorption accelerator
[Adsorption accelerator-containing liquid]
Quaternary ammonium salt of diallylamine polymer 5g / L
(B) Preparation of copper colloid catalyst solution
[Copper solution]
Copper sulfate (as Cu2 +) 0.2 mol / L
[Reducing agent solution]
Sodium borohydride 0.2 mol / L
The reducing agent solution was dropped into a copper solution at 25 ° C. adjusted to pH 4.0 and stirred for 45 minutes.
Copper colloidal particles were formed, but agglomerated and precipitated.

(20) Comparative example 2
Based on the above Example 1, the preparation method of the copper colloid catalyst solution and the electroless copper plating solution and the processing conditions of each step were carried out except that the adsorption accelerator containing liquid and the copper colloid catalyst liquid were prepared with the following composition. Same as Example 1.
In addition, the molar ratio of each component of the catalyst solution is as follows.
Copper salt: colloidal stabilizer = 1: 0.01, copper salt: reducing agent = 1: 1
(A) Preparation of a liquid containing an adsorption accelerator
[Adsorption accelerator-containing liquid]
Quaternary ammonium salt of diallylamine polymer 5g / L
(B) Preparation of copper colloid catalyst solution
[Copper solution]
Copper sulfate (as Cu2 +) 0.2 mol / L
Citric acid 0.002 mol / L
[Reducing agent solution]
Sodium borohydride 0.2 mol / L
The reducing agent solution was dropped into a copper solution at 25 ° C. adjusted to pH 4.0 and stirred for 45 minutes.
Copper colloidal particles were formed, but agglomerated and precipitated.

(21) Comparative Example 3
Based on the above Example 1, the preparation method of the copper colloid catalyst solution and the electroless copper plating solution and the processing conditions of each step were carried out except that the adsorption accelerator containing liquid and the copper colloid catalyst liquid were prepared with the following composition. Same as Example 1.
In addition, the molar ratio of each component of the catalyst solution is as follows.
Copper salt: colloid stabilizer = 1: 36, copper salt: reducing agent = 1: 1
(A) Preparation of a liquid containing an adsorption accelerator
[Adsorption accelerator-containing liquid]
Quaternary ammonium salt of diallylamine polymer 5g / L
(B) Preparation of copper colloid catalyst solution
[Copper solution]
Copper sulfate (as Cu2 +) 0.2 mol / L
Lactic acid 7.2 mol / L
[Reducing agent solution]
Sodium borohydride 0.2 mol / L
The reducing agent solution was dropped into a copper solution at 25 ° C. adjusted to pH 4.0 and stirred for 45 minutes.
Copper colloid particles were not produced.

(22) Comparative Example 4
Based on the above Example 1, the preparation method of the copper colloid catalyst solution and the electroless copper plating solution and the processing conditions of each step were carried out except that the adsorption accelerator containing liquid and the copper colloid catalyst liquid were prepared with the following composition. Same as Example 1.
In addition, the molar ratio of each component of the catalyst solution is as follows.
Copper salt: colloid stabilizer = 1: 4, copper salt: reducing agent = 1: 1
(A) Preparation of a liquid containing an adsorption accelerator
[Adsorption accelerator-containing liquid]
Quaternary ammonium salt of diallylamine polymer 5g / L
Polyoxyalkylene branched decyl ether 1g / L
(B) Preparation of copper colloid catalyst solution
[Copper solution]
Copper sulfate (as Cu2 +) 0.2 mol / L
Citric acid 0.8 mol / L
Polyoxyethylene
-Octylphenyl ether (EO15 mol) 1.0 g / L
[Reducing agent solution]
Sodium borohydride 0.2 mol / L
The reducing agent solution was dropped into a copper solution at 25 ° C. adjusted to pH 4.0 and stirred for 45 minutes.
The average particle diameter of the produced copper colloid particles was about 15 nm.

(23) Comparative Example 5
Based on the above Example 1, the preparation method of the copper colloid catalyst solution and the electroless copper plating solution and the processing conditions of each step were carried out except that the adsorption accelerator containing liquid and the copper colloid catalyst liquid were prepared with the following composition. Same as Example 1.
In addition, the molar ratio of each component of the catalyst solution is as follows.
Copper salt: colloid stabilizer = 1: 4, copper salt: reducing agent = 1: 1
(A) Preparation of a liquid containing an adsorption accelerator
[Adsorption accelerator-containing liquid]
Quaternary ammonium salt of diallylamine polymer 5g / L
Polyoxyalkylene branched decyl ether 1g / L
(B) Preparation of copper colloid catalyst solution
[Copper solution]
Copper sulfate (as Cu2 +) 0.2 mol / L
Citric acid 0.8 mol / L
Polyoxyethylene
-Octylphenyl ether (EO15 mol) 8.0g / L
[Reducing agent solution]
Sodium borohydride 0.2 mol / L
The reducing agent solution was dropped into a copper solution at 25 ° C. adjusted to pH 4.0 and stirred for 45 minutes.
Copper colloidal particles were formed, but agglomerated and precipitated.

(24) Comparative Example 6
This is an example in which the adsorption promoting step is omitted based on the above Example 1, except that the copper colloid catalyst solution is prepared with the following composition, and the method for preparing the copper colloid catalyst solution and the electroless copper plating solution and the treatment of each step The conditions were the same as in Example 1.
In addition, the molar ratio of each component of the catalyst solution is as follows.
Copper salt: colloid stabilizer = 1: 4, copper salt: reducing agent = 1: 1
(A) Preparation of copper colloid catalyst solution
[Copper solution]
Copper sulfate (as Cu2 +) 0.2 mol / L
Citric acid 0.8 mol / L
[Reducing agent solution]
Sodium borohydride 0.2 mol / L
The reducing agent solution was dropped into a copper solution at 25 ° C. adjusted to pH 4.0 and stirred for 45 minutes.
The average particle diameter of the produced copper colloidal particles was about 17 nm.

(25) Comparative Example 7
Based on the above Example 1, the preparation method of the copper colloid catalyst solution and the electroless copper plating solution and the processing conditions of each step were carried out except that the adsorption accelerator containing liquid and the copper colloid catalyst liquid were prepared with the following composition. Same as Example 1.
In addition, the molar ratio of each component of the catalyst solution is as follows.
Copper salt: colloid stabilizer = 1: 4, copper salt: reducing agent = 1: 1
(A) Preparation of a liquid containing an adsorption accelerator
[Adsorption accelerator-containing liquid]
Quaternary ammonium salt of diallylamine polymer 5g / L
(B) Preparation of copper colloid catalyst solution
[Copper solution]
Copper sulfate (as Cu2 +) 0.2 mol / L
Citric acid 0.8 mol / L
Gelatin 1.0g / L
[Reducing agent solution]
Sodium borohydride 0.2 mol / L
The reducing agent solution was dropped into a copper solution at 25 ° C. adjusted to pH 4.0 and stirred for 45 minutes.
Copper colloidal particles were formed, but agglomerated and precipitated.

<< Example of stability of catalyst solution over time >>
Then, about each copper colloid catalyst liquid prepared in the said Examples 1-10, Comparative Examples 1-7, and Reference Examples 1-8 ,
The superiority or inferiority of colloidal stability was evaluated according to the following criteria.
○: No precipitation or decomposition occurred for 1 month after bathing.
X: Sedimented or decomposed immediately after bathing.

<< External appearance test example of copper film deposited by electroless copper plating >>
Next, regarding the electroless copper film obtained by the electroless copper plating method of Examples 1-10, Comparative Examples 1-7, and Reference Examples 1-8 , the superiority or inferiority of the film appearance was visually evaluated according to the following criteria. .
A: The copper plating film was uniform and non-uniform.
○: Unevenness was observed in the copper plating film.
(Triangle | delta): Some non-precipitation (plating lack) was recognized by the copper plating film | membrane.
X: The copper film did not precipitate.
In addition, it is recognized that the “unevenness” of the deposited film has a portion different from the surroundings in the denseness and smoothness of the film. The “unevenness” of the film is a different viewpoint from the uniformity of the film.

《Test results on stability of copper colloid catalyst solution over time and coating appearance》
Film appearance Aging stability Film appearance Aging stability Example 1 ◎ ○ Comparative Example 1 × ×
Example 2 ◎ ○ Comparative Example 2 × ×
Example 3 ○ ○ Comparative Example 3 × ×
Example 4 ◎ ○ Comparative Example 4 △ ○
Example 5 ○ ○ Comparative Example 5 × ○
Example 6 ◎ ○ Comparative Example 6 △ ○
Example 7 ◎ ○ Comparative Example 7 Δ ×
Example 8
Example 9
Example 10 ◎ ○
Reference Example 1 ◎ ○
Reference Example 2 ◎ ○
Reference Example 3 ◎ ○
Reference example 4
Reference Example 5 ◎ ○
Reference Example 6 ◎ ○
Reference Example 7 ◎ ○
Reference Example 8 ◎ ○

《Comprehensive evaluation of catalyst solution over time and plating film appearance》
In Comparative Example 1 where the colloidal stabilizer was lacking in the copper colloid catalyst solution, the catalyst solution was inferior in stability over time, and therefore no copper film was deposited even when electroless plating was performed on the non-conductive substrate after contact with the catalyst solution. .
Further, when the relative amount of the colloidal stabilizer is too small in the ratio of the colloidal stabilizer to the copper salt, as shown in Comparative Example 2, the stability of the catalyst solution over time is still inferior, so that the copper film is deposited in electroless plating. There was no. This is the same when the relative amount of the colloidal stabilizer is too large. As shown in Comparative Example 3, the catalyst solution was inferior in stability over time, and no copper film was deposited in electroless plating.
In Comparative Example 6 in which the catalyst was applied to the non-conductive substrate without adsorption promoting treatment and electroless copper plating was performed, the temporal stability of the catalyst solution was the same as that of the example. Example of "adhesion of copper colloidal particles to the substrate due to lack of catalytic activity due to the absence of pretreatment for promotion of adsorption prior to catalyst application because of" plating chipping "in which unprecipitated parts occur. It can be judged that it is inferior to.

On the other hand, in Examples 1 to 10 in which the catalyst application treatment was performed after the adsorption promotion pretreatment, and then the electroless copper plating was performed, all of the catalyst solutions had good temporal stability, and were deposited by electroless plating. The copper film to be applied was generally uniform and excellent in uniformity. Reference Examples 1-8 were the same.
When the Examples 1 to 10 are compared with Comparative Example 1 above, the catalyst solution contains not only a copper salt and a reducing agent but also a colloidal stabilizer in order to obtain a uniform and uniform copper film. It turns out to be essential. Further, when Examples 1 to 10 are compared with Comparative Examples 2 to 3, in order to obtain a copper film having no unevenness and excellent uniformity, it is not sufficient to contain a colloid stabilizer, but a colloid stabilizer and a copper salt. It can be judged that optimization of the content ratio is important.
In Comparative Example 4 in which the surfactant was contained in the catalyst solution in excess of the suppression regulation amount of the present invention 1, “plating failure” in which non-deposition occurred in a part of the copper film deposited in electroless plating was observed. And in the comparative example 5 which made the catalyst solution contain more surfactant than the comparative example 4, the copper membrane | film | coat did not precipitate in electroless plating. On the other hand, in Example 5 in which the surfactant was suppressed to a very small amount not more than the specified amount of the present invention 1, the copper film was smoothly deposited without any plating defects in electroless plating (however, the film Was found to be uneven). Moreover, in Examples 1-4 and Examples 6-10 which do not contain a surfactant in the catalyst solution, naturally there was no unevenness and an excellent uniform copper film was deposited. That is, if a surfactant is added to the catalyst solution exceeding the specified value of the present invention, the catalyst activity of the copper colloid catalyst solution is reduced, and the copper film obtained by electroless plating is not plated, and the surfactant is further removed. When the content of the catalyst is increased, the catalytic activity of the liquid is lost and the copper film does not precipitate. Therefore, the copper film is deposited smoothly only when the content of the surfactant is suppressed to a very small amount. Since the activity of the catalyst solution decreases as the surfactant content increases, it can be judged that it is basically preferable not to add a surfactant in order to maintain the catalyst activity of the copper colloid catalyst solution. Further, in Comparative Example 7 in which gelatin, which is a representative example of a naturally derived water-soluble polymer, is contained in a catalyst solution, gelatin is added to the catalyst solution of the present invention 1 in an extra form . Inferior to electroless At the time of cleaning, undeposited “plating defects” were observed in part of the obtained copper film. On the other hand, in Reference Examples 1 to 8 containing a synthetic water-soluble polymer in the catalyst solution, an excellent uniform copper film was deposited without any unevenness. In order to obtain an excellent practical copper film, It was confirmed that it is necessary to select a synthetic polymer among water-soluble polymers.

Next, Examples 1 to 10 will be examined in detail.
The relative evaluation with the other examples will be described with reference to the example 1. First, in Example 1, a non-conductive substrate is pretreated with an adsorption accelerator containing a quaternary ammonium salt of diallylamine polymer which is a cationic surfactant, copper sulfate is used as a copper salt, and sodium borohydride is used as a reducing agent. This is an example of electroless copper plating after applying a catalyst with a catalyst solution containing citric acid as a colloidal stabilizer, but the catalyst solution has good stability over time, and precipitation occurs even after one month has passed since building bath, There was no decomposition, and the copper film obtained by electroless plating was excellent in uniformity and no precipitation unevenness was observed.
Example 2 is an example in which the content ratio of the colloidal stabilizer to the copper salt is lowered with respect to Example 1, Example 4 is an example in which the content of the reducing agent is lowered with respect to Example 1, and Example 6 is a colloidal stability. In this example, the agent was changed from citric acid of Example 1 to glycolic acid. The stability with time of the catalyst solution and the appearance of the plating film were evaluated in the same manner as in Example 1.
EXAMPLE 7 in which the copper salt of methanesulfonic acid copper relative to Example 1, but the embodiment 8 is an example of a copper salt copper citrate, the appearance of aging stability and plating film of the catalyst solution The evaluation was the same as in Example 1.
As described above, in Examples 1 to 4 and Examples 6 to 10 in which no surfactant was contained in the catalyst solution, the plating film was generally excellent in uniformity and no unevenness was observed. Further, in Example 5 where the surfactant is present in a very small amount less than or equal to the specified amount of the present invention 1, the copper film was smoothly deposited without the occurrence of chipping or the like in electroless plating, but deposition unevenness was observed in the film. It was.
Reference Example containing the PVP Reference Example containing (average molecular weight: 40,000) 1, similarly Reference Example 4 which contained Reference Example 2, PEI containing the PEG, PVP (average molecular weight 300,000) as a water-soluble polymer to the catalyst solution In Reference Example 6 containing 3 and 5 and PAM, the stability over time of the catalyst solution and the appearance of the plating film were evaluated in the same manner as in Example 1.
In contrast to Example 1 in which the catalyst solution was set to pH 4.0, in Example 7 at pH 3, Example 8 at pH 5, and Example 10 at pH 10 , the stability over time of the catalyst solution and the appearance of the plating film were respectively shown. The evaluation was the same as in Example 1.

Claims (7)

In an aqueous copper colloid catalyst solution for applying a catalyst by bringing it into contact with a non-conductive substrate to be electrolessly plated with copper,
(A) a soluble copper salt;
(B) a reducing agent;
(C) at least one colloidal stabilizer selected from the group consisting of oxycarboxylic acids , aminocarboxylic acids, and polycarboxylic acids ,
The content molar ratio of the components (A) and (C) is A: C = 1: 0.03 to 1:35 , the content of the component (A) is 0.05 to 0.5 mol / L, and the components The content molar ratio of (A) and (B) is A: B = 1: 0.1 to 1: 5,
It contains no surfactant or the surfactant content is 950 mg / L or less ,
An aqueous copper colloid catalyst solution for electroless copper plating , having a pH of 1 to 6 or 8 to 12 and a copper colloid having an average particle diameter of 1 to 250 nm . . Reducing agent (B) is from borohydride compounds, amine boranes, hypophosphorous acids, aldehydes, ascorbic acids, hydrazines, polyhydric phenols, polyhydric naphthols, phenolsulfonic acids, naphtholsulfonic acids, sulfinic acids The aqueous copper colloid catalyst solution for electroless copper plating according to claim 1 , wherein the aqueous copper colloid catalyst solution is at least one selected from the group consisting of: Oxycarboxylic acids (C) are citric acid, tartaric acid, malic acid, gluconic acid, golcoheptonic acid, glycolic acid, lactic acid, trioxybutyric acid, isocitric acid, tartronic acid, glyceric acid, hydroxybutyric acid, leucine acid, citramalic acid, and these 3. The aqueous copper colloid catalyst solution for electroless copper plating according to claim 1, wherein the aqueous copper colloid catalyst solution is at least one selected from the group consisting of these salts. Aminocarboxylic acids (C) are hydroxyethylethylenediaminetriacetic acid, diethylenetriaminepentaacetic acid, triethylenetetraminehexaacetic acid, ethylenediaminetetraacetic acid, ethylenediaminetetrapropionic acid, nitrilotriacetic acid, iminodiacetic acid, hydroxyethyliminodiacetic acid, iminodipropionic acid. 1,3-propanediaminetetraacetic acid, 1,3-diamino-2-hydroxypropanetetraacetic acid, glycol etherdiaminetetraacetic acid, metaphenylenediaminetetraacetic acid, 1,2-diaminocyclohexane-N, N, N ′, N From the group consisting of '-tetraacetic acid, diaminopropionic acid, glutamic acid, dicarboxymethyl glutamic acid, ornithine, cysteine, N, N-bis (2-hydroxyethyl) glycine, (S, S) -ethylenediamine succinic acid and salts thereof Was selected Aqueous copper colloid catalyst solution for electroless copper plating according to any one of claims 1 to 3, characterized in that a type even without. The polycarboxylic acid (C) is at least one 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 salts thereof. The aqueous copper colloid catalyst solution for electroless copper plating according to any one of claims 1 to 4 . (A) Adsorption in which a nonconductive substrate is immersed in a liquid containing at least one adsorption accelerator selected from the group consisting of nonionic surfactants, cationic surfactants, anionic surfactants, and amphoteric surfactants An acceleration process (pretreatment process);
(B) a catalyst application step of immersing the non-conductive substrate in the aqueous copper colloid catalyst solution according to any one of claims 1 to 5 to adsorb the copper colloid particles on the substrate surface;
(C) an electroless plating step of forming a copper film using an electroless copper plating solution on the adsorption-treated substrate. The electroless copper plating method according to claim 6 , wherein the adsorption promoter in the step (a) is a cationic surfactant and / or an amphoteric surfactant.