JP2003082468A - Catalyst solution for electroless plating - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an electroless plating catalyst which can be suitably used for applying an electroless plating catalyst to only a conductor part of a material to be plated consisting of the conductor part and an insulator part, which hardly causes nondeposition of plating on the conductor part and spreading of plating to the insulator part, in which adsorption of catalytic metal to a catalyzing tank can be minimized and which exhibits excellent stability. SOLUTION: The catalyst solution for electroless plating is composed of an aqueous solution containing (i) at least one compound selected from the group consisting of gold compounds, silver compounds, palladium compounds, ruthenium compounds, rhodium compounds, platinum compounds and copper compounds and (ii) a water-soluble nitrogen compound containing hexavalent sulfur.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a catalyst liquid for electroless plating.

[0002]

2. Description of the Related Art Using an electronic component substrate having a conductor pattern of W, Mo, Cu or the like as an object to be plated to perform electroless plating only on the conductor pattern, a catalyst metal for starting electroless plating is used. It is necessary to apply the nucleus only to the surface of the conductor pattern.

Conventionally, an aqueous solution in which a water-soluble catalytic metal compound is dissolved is mainly used as a catalyst for electroless plating. However, when such a catalyst aqueous solution is used as a catalyst solution for an article on which a conductor pattern is formed, the deposition of catalytic metal nuclei on the conductor pattern is insufficient and electroless plating may be deposited unevenly. Alternatively, the electroless plating reaction may not start, and partial plating non-precipitation called a skip phenomenon may occur.

Further, in the above catalyst aqueous solution, the catalyst metal exists as free metal ions and its concentration is high, so that the metal colloidation of the catalyst metal ions easily proceeds, and the surface of the substrate other than the conductor pattern is colloided. There is also a drawback that electroless plating is likely to be deposited also on this portion due to the deposition of the catalyst metal, and plating spread, which is a phenomenon in which electroless plating is deposited on the substrate surface other than the conductor pattern, occurs.

Therefore, an attempt has been made to prevent the skip phenomenon and the plating spread by complexing the catalyst metal with a chelating agent such as a carboxylic acid compound or an aminocarboxylic acid compound.

However, even when using a catalyst liquid containing these chelating agents, the skip phenomenon and the plating spread cannot be sufficiently prevented. Moreover, when a chelating agent such as a carboxylic acid compound or an aminocarboxylic acid compound is used, the catalytic metal complex is easily adsorbed to the resin treatment tank used for the catalyst application treatment, and the catalyst inside the treatment tank is treated within a few days. There is a problem that the catalyst metal concentration decreases.

[0007]

The main object of the present invention is to:
A catalyst for electroless plating that is suitable for applying a catalyst for electroless plating only to a conductor portion in an object to be plated consisting of a conductor portion and an insulator portion. It is an object of the present invention to provide a catalyst for electroless plating which is less likely to spread in the plating, has less adsorption of the catalyst metal in the catalyst applying treatment tank, and is excellent in stability.

[0008]

Means for Solving the Problems As a result of intensive studies to achieve the above object, the present inventor has found that gold compounds, silver compounds, palladium compounds, ruthenium compounds, rhodium compounds, platinum compounds and copper are used as catalyst substances. A conductor pattern was formed by using a novel electroless plating catalyst liquid containing at least one compound selected from the compounds and further containing a water-soluble nitrogen compound containing hexavalent sulfur as a chelating agent. It has been found that it is possible to form a good electroless plating film only on the conductor pattern without causing a skip phenomenon or plating spread when an electronic component substrate or the like is to be plated. The invention was completed.

That is, the present invention provides the following electroless plating catalyst liquid. 1. (I) gold compound, silver compound, palladium compound,
A catalyst liquid for electroless plating comprising an aqueous solution containing at least one compound selected from the group consisting of ruthenium compounds, rhodium compounds, platinum compounds and copper compounds, and (ii) a water-soluble nitrogen compound containing hexavalent sulfur. 2. (I) gold compound, silver compound, palladium compound,
Water-soluble containing at least one compound selected from the group consisting of ruthenium compounds, rhodium compounds, platinum compounds and copper compounds as a metal concentration of 1 × 10 ^{−5 to} 0.1 mol / l, and (ii) hexavalent sulfur 2x nitrogen compounds
A catalyst solution for electroless plating, which comprises an aqueous solution containing 10 ^{−5 to} 0.5 mol / l.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION The catalyst liquid for electroless plating of the present invention is (i) at least one selected from the group consisting of gold compounds, silver compounds, palladium compounds, ruthenium compounds, rhodium compounds, platinum compounds and copper compounds. And a water-soluble nitrogen compound containing (ii) hexavalent sulfur.

The catalyst liquid of the present invention will be specifically described below.

The catalyst substance contained in the catalyst liquid for electroless plating of the present invention includes a gold compound, a silver compound, a palladium compound,
At least one compound selected from the group consisting of ruthenium compounds, rhodium compounds, platinum compounds and copper compounds (hereinafter sometimes referred to as "catalyst metal compound")
Is.

As these catalytic metal compounds, any water-soluble compound containing the above-mentioned catalytic metal component can be used without particular limitation. Among these, examples of the water-soluble gold compound include gold sulfite, gold sulfate, potassium gold cyanide, gold chloride and the like, and examples of the water-soluble silver compound include silver fluoride, silver nitrate, silver sulfate, silver acetate and the like. Can be illustrated,
Examples of the water-soluble palladium compound include palladium chloride, palladium sulfate, palladium nitrate, palladium acetate, ammine palladium, and the like, and examples of the water-soluble ruthenium compound include ruthenate, ruthenium chloride, ruthenium oxide, and the like, water-soluble rhodium. As a compound,
Examples of rhodium chloride, rhodium nitrate, rhodium acetate, etc., examples of water-soluble platinum compounds include platinum chloride, etc., examples of water-soluble copper compounds include copper phthalate, copper oxide, copper oxalate, copper gluconate, formic acid. Copper, copper hydroxide, copper sulfate,
Examples include copper chloride, copper pyrophosphate, copper carbonate and the like. These catalytic metal compounds may be used alone or in combination of two or more.

The concentration of the catalytic metal compound in the catalyst liquid is preferably about 1 × 10 ^{-5 to} 0.1 mol / l as the metal concentration, and 2 × 10 ^-5 to 1 × 10 ^-2 mol / l. It is more preferable to adjust the degree.

In the catalyst liquid of the present invention, it is further necessary to add a water-soluble nitrogen compound containing hexavalent sulfur. By adding a catalyst using the catalyst liquid of the present invention containing such a specific water-soluble nitrogen compound, W, M
o. When an article having a conductor pattern made of Cu or the like formed on various non-conductors is used as an object to be plated, a skip phenomenon and plating spread are prevented, and a good electroless plating film is formed only on the conductor pattern. It becomes possible. The reason for this is not clear, but by using a water-soluble nitrogen compound containing hexavalent sulfur,
The catalyst metal ions are chelated to reduce the concentration of free metal ions and prevent the metal ions from becoming metal colloids. Moreover, the formed catalyst metal complex has a low adsorbing power to the resin, etc. It is thought that there is almost no adhesion of catalytic metal nuclei to the outside and deposition of electroless plating outside the conductor pattern is prevented. Furthermore, W, Mo. Cu
By facilitating the dissolution of the metal forming the conductor pattern such as, the substitution reaction with metal ions is facilitated, the deposition of the catalytic metal on the conductor pattern is promoted, and the skip phenomenon is prevented from occurring. I think that the.

The water-soluble nitrogen compound containing hexavalent sulfur that can be used in the present invention is not particularly limited as long as it is a water-soluble compound containing hexavalent sulfur and nitrogen in the molecule. -SO ₂ as the group containing sulfur of
Amine containing a -group, a nitrogen-containing heterocyclic compound and the like can be preferably used. The amine compound may be any of primary amine, secondary amine, and tertiary amine. As the nitrogen-containing heterocyclic compound, a saturated or unsaturated 4- to 8-membered ring containing at least one nitrogen atom as a ring-constituting atom is used. Compounds containing saturated heterocycles can be used.

Specific examples of such water-soluble nitrogen compounds include (p-amidinophenyl) methanesulfonyl fluoride hydrochloride, methanesulfonamide, sulfamic acid, aminomethanesulfonic acid, aminoethanesulfone as primary amine compounds. Acid, p-aminophenol sulfate, 3,3'-diaminodiphenyl sulfone, 4,4 '
-Diaminodiphenyl sulfone, p-toluene sulfonamide, sulfanilamide, sulfanilic acid, 4-amino-2-methylbenzene-1-sulfonic acid, 2-amino-5-methylbenzene-1-sulfonic acid, benzenesulfonamide, N -(2-acetamido) -2-aminoethanesulfonic acid, o-aminobenzenesulfonic acid, p
-Aminobenzenesulfonamide, 1-chlorobenzene-2,4-disulfonamide, 1-amino-2-naphthol-4-sulfonic acid, 2-amino-5-naphthol-
7-sulfonic acid, 8-amino-1-naphthol-3,6
-Disulfonic acid (sodium salt), sulfanilamide, taurocyanamine, 2-aminopropanesulfonic acid and the like can be mentioned. Further, as the secondary amine compound, benzenesulfohydroxamic acid, N-cyclohexyl-3-aminopropanesulfonic acid, N-tris (hydroxymethyl) methyl-3-aminopropanesulfonic acid, N-tris (hydroxymethyl) methyl Examples include 2-aminoethanesulfonic acid, 2-hydroxy-N-tris (hydroxymethyl) methyl-3-aminopropanesulfonic acid, N-cyclohexyl-2-hydroxy-3-aminopropanesulfonic acid. As the tertiary amine compound, N, N-bis (2-hydroxyethyl) -2
-Aminoethanesulfonic acid, 3- [N, N-bis (2-
Examples thereof include hydroxyethyl) amino] -2-hydroxypropanesulfonic acid. As the heterocyclic compound,
4- (2-hydroxyethyl) 1-piperazineethanesulfonic acid, 3- (N-morpholino) propanesulfonic acid, 2- (N-morpholino) ethanesulfonic acid, piperazine-N, N'-bis (2-ethanesulfone) Acid), 2-
Hydroxy-3- [4- (2-hydroxyethyl) -1
-Piperazinyl] propanesulfonic acid, piperazine-
Examples thereof include N, N'-bis (2-hydroxypropane-3-sulfonic acid), 2-hydroxy-3-morpholinopropanesulfonic acid, pyridinesulfonic acid and diazoxide.

The water-soluble nitrogen compounds containing hexavalent sulfur may be used alone or in combination of two or more.

The concentration of the water-soluble nitrogen compound containing hexavalent sulfur in the catalyst solution is not particularly limited, but is usually
It is preferably about 2 × 10 ^{−5 to} 0.5 mol / l, more preferably about 5 × 10 ^{−5 to} 0.2 mol / l, and about 1 × 10 ^{−4 to} 0.1 mol / l. More preferably.

The method for performing electroless plating using the above-mentioned catalyst solution of the present invention will be specifically described below.

The object to be plated is not particularly limited, and various articles which have been conventionally targets for electroless plating can be targets for plating. In particular, according to the catalyst solution of the present invention, for an article composed of a conductor portion and an insulator portion, the catalyst for electroless plating can be selectively applied only to the conductor portion, so that an insulating material such as ceramics, resin, or glass can be used. It is particularly effective to use an article on which a conductor pattern of Mo, Cu, W or the like is formed, for example, a ceramics substrate, a printed circuit board, a chip or the like as the object to be plated.

First, such an object to be plated is subjected to pretreatment according to a conventional method. The pretreatment step is not particularly limited, but generally, the immersion degreasing, pickling, etc. may be performed by a known method according to the material to be treated.

As the degreasing liquid used for the immersion degreasing, an alkaline degreasing liquid, an acidic degreasing liquid,
The solvent-based degreasing liquid may be appropriately selected and used. In particular, when the conductor pattern is Mo, W, or the like, an alkaline degreasing agent is often used because it has a property of being easily dissolved in alkali.

After the degreasing treatment, the oxide film on the surface of the conductor is usually removed. However, when Mo, W, etc. are degreased with an alkaline degreasing agent, this step can be omitted.
For removing the oxide film, a sodium persulfate solution, an ammonium persulfate solution, a cyanide compound solution, a sulfuric acid-hydrogen peroxide aqueous solution or the like can be usually used. When the conductor portion is formed of a glass paste containing conductive metal powder, glass etching is usually performed using an alkaline solution, a fluoride solution or the like. This process may be performed according to a conventional method.

Next, if necessary, pickling is performed. The pickling may be carried out according to a conventional method. Usually, the object to be plated may be immersed in an aqueous solution containing a mineral acid such as hydrochloric acid, sulfuric acid or nitric acid in an acid concentration of about 0.1 to 5 mol / l. The treatment temperature is preferably room temperature to about 40 ° C., and the treatment time may be about 5 seconds to 2 minutes.

After the pretreatment, the object to be plated is brought into contact with the catalyst solution of the present invention, so that the catalyst can be applied to the object to be plated. The method of bringing the object to be plated into contact with the catalyst solution is not particularly limited, but normally, the object to be plated may be immersed in the catalyst solution.

The pH of the catalyst solution is not particularly limited, but normally, the pH may be about 0.5 to 12.5,
The pH is preferably about 1.5 to 11, and the pH is 2 to
It is more preferable to set it to about 10. The temperature of the catalyst solution and the treatment time are not limited, but are usually 0 to 90 ° C.
Degree, preferably about 5 to 80 ° C., more preferably 15
The object to be plated may be immersed in the catalyst solution at about 75 ° C. for about 5 seconds to 2 hours, and generally, a treatment time of about 15 seconds to 30 minutes is practical.

After applying the catalyst by the above-mentioned method, pickling is performed if necessary. Particularly, in the case of a material in which electroless plating deposition is likely to occur also in an insulator portion other than the conductor portion, pickling can suppress the deposition of electroless plating on portions other than the conductor portion. In the pickling treatment, for example, a mineral acid such as hydrochloric acid, sulfuric acid or nitric acid is usually used as an acid concentration of 0.
The object to be plated may be immersed in an aqueous solution containing about 1 to 5 mol / l. The treatment temperature is preferably room temperature to about 40 ° C., and the treatment time may be about 5 seconds to 2 minutes.

After the catalyst is applied by the above-mentioned method, electroless plating is carried out according to a conventional method, whereby an electroless plating film can be formed only on the conductor part of the article composed of the conductor part and the insulator part. it can. The type of electroless plating is not particularly limited, but usually electroless copper plating, electroless nickel boron plating, electroless nickel phosphorus plating, etc. are mainly used. Regarding the conditions of electroless plating, a conventional method may be used. The film thickness of the electroless plating may be appropriately determined according to the application of the object to be plated, and, for example, when an electronic component substrate having a conductor pattern is used as the object to be plated, it is usually 3 to 10
In many cases, the plating thickness is about μm.

[0030]

The catalyst solution for electroless plating of the present invention imparts the catalyst for electroless plating only to the conductor portion when an article composed of the conductor portion and the insulator portion is to be plated. It is a catalyst for electroless plating suitable for. Moreover, since excellent catalytic activity can be imparted to the conductor portion,
It is possible to prevent a non-precipitated portion of electroless plating from occurring in the conductor portion.

By using the catalyst solution of the present invention, for example, when an electronic component substrate on which a conductor pattern is formed is used as an object to be plated, the spread of plating on the insulator portion on the substrate and the skip phenomenon on the conductor pattern. Is suppressed,
It becomes possible to form a fine pattern. In addition, the catalyst liquid of the present invention is a catalyst liquid that is less adsorbed to the catalyst-providing treatment tank and can be used stably for a long period of time.

[0032]

EXAMPLES The present invention will be described in more detail with reference to examples.

Example 1 As a material to be plated, a glass paste containing a conductive metal powder of W, Mo or Cu was applied on an alumina plate and baked to form a ceramic substrate on which a conductor pattern was formed, and on a glass epoxy resin. A glass epoxy substrate on which a conductor pattern was formed by electrolytic copper plating was used. The width of the conductor pattern is 50 for both substrates.
and the width of the insulator part between the conductor patterns is 50 μm.
And

First, as a pretreatment, a ceramic substrate having a conductor pattern formed of a glass paste containing a conductive metal powder was subjected to a degreasing treatment by immersing it in an aqueous solution of 30 g / l of sodium hydroxide at 60 ° C. for 5 minutes. After 35
It was pickled by immersing it in a 100 ml / l aqueous solution of 100% hydrochloric acid at 25 ° C. for 1 minute. Further, the glass epoxy substrate on which the conductor pattern was formed by electrolytic copper plating was subjected to degreasing treatment by immersing it in an acidic degreasing agent (trade name: Acid Clean 115, manufactured by Okuno Chemical Industries Co., Ltd.) at 45 ° C. for 5 minutes. Then, it was immersed in an aqueous solution of 150 g / l of sodium persulfate at 25 ° C. for 1 minute for etching, and then immersed in an aqueous solution of 100 ml / l of 35% hydrochloric acid for 1 minute at 25 ° C. to perform pickling.

Next, after the catalyst application operation was carried out by immersing in a catalyst solution having the composition and solution temperature shown in Table 1 below for 5 minutes, 35
It was pickled by immersing it in a 100 ml / l aqueous solution of 100% hydrochloric acid at 25 ° C. for 1 minute.

After that, the electroless plating treatment shown in Table 2 below was performed. Trade names for electroless Ni-B plating:
Using an electroless Ni-B plating solution of Top Chemialoy 66 (manufactured by Okuno Chemical Industries Co., Ltd.), it was immersed in the plating solution at a solution temperature of 65 ° C for 60 minutes to form a plating film of about 7 µm. For electroless Ni-P plating, trade name: ICP
Nicolon GM (E) (Okuno Pharmaceutical Co., Ltd.) electroless
A Ni-P plating solution was used and immersed in the plating solution at a solution temperature of 80 ° C. for 30 minutes to form a plating film of about 7 μm.
For electroless copper plating, trade name: ASH Copper A
Using an electroless Cu plating solution (manufactured by Okuno Chemical Industries Co., Ltd.), immersing it in the plating solution at a liquid temperature of 55 ° C. for 140 minutes,
A plating film of about 7 μm was formed.

With respect to the electroless plating film formed by each of the above-mentioned methods, the out-of-pattern deposition, plating chipping and bath stability were evaluated by the following methods. The results are shown in Table 2 below. (1) Observed under a microscope with a magnification of 100 times out of pattern and observed when the precipitation outside the pattern was 2 μm or more as “existence of precipitation outside the pattern”, and when the precipitation outside the pattern was less than 2 μm as “absence” outside the pattern. . (2) If the plating is completely deposited on the conductor pattern by observing with a microscope with a plating deficiency of 100 times, the plating deficiency is "none",
The case where there was even one part where no plating was deposited on the conductor pattern was evaluated as "presence of plating", and the case where no plating was deposited on the conductor pattern was evaluated as "not deposited". (3) Bath stability Leave the electroless plating catalyst solution at the treatment temperature for 7 days,
"Precipitation has occurred" when there is a precipitate visually, "adsorption on the wall" when there is no precipitation but the decrease in precious metal concentration is 5% or more, and "decrease" when the decrease in precious metal concentration is less than 5%. It was evaluated as "stable".

[0038]

[Table 1]

[0039]

[Table 2]

   ─────────────────────────────────────────────────── ─── Continued front page    F-term (reference) 4K022 AA02 AA42 BA04 BA08 BA14                       BA16 BA31 BA32 BA35 CA06                       CA20 CA21 CA22 DA01                 5E343 AA02 AA15 AA17 AA23 BB24                       BB39 BB40 BB72 CC43 DD03                       DD33 EE02 EE52 ER04 GG20

Claims (2)

[Claims] 1. At least one compound selected from the group consisting of (i) gold compounds, silver compounds, palladium compounds, ruthenium compounds, rhodium compounds, platinum compounds and copper compounds, and (ii) hexavalent sulfur. A catalyst liquid for electroless plating comprising an aqueous solution containing a water-soluble nitrogen compound. 2. At least one compound selected from the group consisting of (i) a gold compound, a silver compound, a palladium compound, a ruthenium compound, a rhodium compound, a platinum compound and a copper compound, in an amount of 1 × 10 ^{−5 to} 0.1 mol / mol. l, and (i
i) Add water-soluble nitrogen compound containing hexavalent sulfur to 2 × 10 ⁻⁵
A catalyst solution for electroless plating, which comprises an aqueous solution containing 0.5 mol / l.