JPH06101054A - Copper-based material selection type electroless plating catalyst solution - Google Patents

Abstract

(57) [Abstract] [Purpose] The present invention is capable of selectively activating a copper-based material as a catalyst and preventing a skip phenomenon, a bridge phenomenon, and the like.
Another object is to provide a cost-effective catalyst solution for electroless plating. The present invention comprises an aqueous solution containing (I) at least one of a nickel compound and a cobalt compound, and (II) at least one of thioureas, a copper-based material selective electroless plating. A catalyst liquid for use is provided.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a copper-based material selection type electroless plating catalyst solution.

[0002]

2. Description of the Related Art When electroless plating of Ni, Pd, Pd-Ni or the like using a hypophosphite compound as a reducing agent is performed on a copper-based material, it is usually used for reduction precipitation of a plating film. After applying a Pd compound as a catalyst on the material, electroless plating is performed. In such a case, the catalyst application method includes a two-step treatment with SnCl ₂ solution and PdCl ₂ solution
For example, treatment with a PdCl ₂ / SnCl ₂ mixed system acidic aqueous hydrochloric acid solution is performed. However, when these treatment methods are applied to a printed circuit board, a ceramic substrate, a chip component or the like in which an insulator and a conductor are integrated, all of the insulating portion and the conductor portion are catalytically activated. As a result, the entire surface is plated in the electroless plating process, and the plating film cannot be formed only on the conductor portion. There is also known a method of catalytically activating a copper-based material by using an acidic aqueous solution of PdCl ₂ in hydrochloric acid. In this case as well, a part of the catalyst component is adsorbed on the insulator part, and the insulator part is formed during the plating process. There is a problem that a bridge (plating bridge) phenomenon occurs in which the conductors are partially coupled to each other when a plating film is formed on a part of the surface and the space between the conductors is narrow.

As a countermeasure against this, measures have been taken to raise the pH to weaken the catalytic activity, but even if the pH is raised to about 5, the plating bridge cannot be eliminated, while the pH is 6
In the case of the above, colloidal precipitation occurs, which makes practical handling difficult.

Further, the concentration of PdCl ₂ is reduced to weaken the catalytic activity, but in this case, the plating bridge disappears, but on the contrary, the catalytic activity becomes too weak and a part of the plating is lost. There is a problem that it causes a phenomenon that does not exist (skip phenomenon).

[0005]

In view of the above-mentioned state of the art, the inventor of the present invention is capable of selectively activating only copper-based materials and does not cause skipping phenomenon, bridging phenomenon, etc. We have conducted extensive research to find a catalyst for plating. As a result, according to the aqueous solution containing at least one of the nickel compound and the cobalt compound and the thioureas, only the copper-based material can be selectively catalytically activated, and
It has been found that the skip phenomenon, the bridge phenomenon, etc. can be prevented, and further, the cost is very advantageous because the palladium compound is not used.

That is, the present invention relates to (I) at least one kind of nickel compound and cobalt compound 0.001 to 3 mol / l, and (II) at least one kind of thiourea.
The present invention relates to a copper-based material selection type electroless plating catalyst solution comprising an aqueous solution containing 05 to 5 mol / l.

In the catalyst liquid of the present invention, it is necessary to use at least one kind of nickel compound and cobalt compound as the catalyst compound.

Examples of the nickel compound used in the present invention include nickel acetate, nickel ammonium sulfate, nickel benzoate, nickel bromide, nickel carbonate, nickel chloride, nickel citrate, nickel hydroxide, nickel iodide, nickel nitrate, and silver. Nickel oxide, nickel oxide,
Examples include nickel stearate, nickel sulfamate, and nickel sulfate.

The cobalt compounds used in the present invention include cobalt acetate, cobalt ammonium chloride, cobalt ammonium sulfate, cobalt bromide, cobalt carbonate, cobalt chloride, diammonium sulfate cobalt, formate cobalt, cobalt naphthenate and nitric acid. Examples thereof include cobalt, cobalt oleate, cobalt oxalate, cobalt oxide, cobalt stearate, and cobalt sulfate.

In the present invention, the addition amount of at least one compound selected from nickel compounds and cobalt compounds is about 0.001 to 3 mol / l, preferably 0.0
It may be about 1 to 1.5 mol / l. This added amount is
If it is less than 0.001 mol / l, the skip phenomenon tends to occur, while if it exceeds 3 mol / l, it is uneconomical, which is not preferable.

In the catalyst liquid of the present invention, it is necessary to add thioureas in addition to at least one compound selected from nickel compounds and cobalt compounds. As a result, the deposition potential of the copper-based material can be lowered, and substitution with nickel or cobalt can be made possible.

Examples of thioureas include thiourea, dimethylthiourea, trimethylthiourea, allylthiourea, acetylthiourea, ethylenethiourea and phenylthiourea, and at least one of them may be used.
The addition amount is about 0.05 to 5 mol / l, preferably 0.1.
The amount may be about 5 to 3 mol / l, and if it is less than 0.05 mol / l, the skip phenomenon tends to occur, and if it exceeds 5 mol / l, it is uneconomical, which is not preferable.

In the catalyst liquid of the present invention, if necessary,
By incorporating a chelating agent, the stability of the catalyst liquid can be improved.

Examples of the chelating agent usable in the present invention include the compounds shown in the following (a) to (g).

(A) General formula

[0016]

[Chemical 8]

(In the formulae, X ¹ , X ² and X ³ are the same or different and each represents --CH ₂ CO ₂ M, --CH ₂ PO ₃ MM, --CH
(CH ₃₎ CO ₂ M or indicates _{-CH 2 CH 2 CO 2 M,} X 4
_{-CH 2 CO 2 M, -CH 2} PO 3 MM is, -CH ₂ CH ₂ O
_{H, -CH (CH 3) CO} 2 M or -CH ₂ CH ₂ CO ₂
Indicates M, X ⁵ is _{H, -CH 2 CO 2 M,} -CH 2 PO 3 M
_{M, -CH (CH 3) CO} 2 M or -CH ₂ CH ₂ CO ₂ M
Indicates. In the above, M is the same or different and each represents H, K, Na or NH ₄ , and n is an integer of 0 to 2), (b) a general formula

[0018]

[Chemical 9]

(Where X is⁶And X⁷Are the same or different
H and C respectively_1-5Alkyl, aralkyl, aralkeni
Le, aryl, -CH₂CO₂M, -CH (CH₃) CO₂
M, -CH₂CH₂CO₂M, -CH₂PO₃MM or -C
H₂CH₂OH, X⁸Is H, C_1-5Alkyl, ara
Ruquil, aryl, -CH₂CO₂M, -CH (CH₃)
CO ₂M, -CH₂CH₂CO₂M, -CH₂PO₃MM,-
CH₂CH₂OH,-(CH₂)_p-NH₂Or-[(C
H₂)_q-NH]_rIndicates -H. In the above, M is the above
, P is an integer of 0 to 10, q is an integer of 1 to 3, r is
A compound represented by an integer of 1 to 10), (c) one
General formula

[0020]

[Chemical 10]

(In the formula, X ⁹ is H, --CH ₂ CO ₂ M or-
PO ₃ MM, X ¹⁰ represents C _1-5 alkyl, —CO ₂ M or —CH ₂ CO ₂ M, and X ¹¹ represents —CO ₂ M, —CH ₂ C.
O ₂ M, indicates -PO ₃ MM or _{-CH (OH) CO 2 M,} X 12 represents H or OH. In the above, M is the same as defined above, (d) the general formula

[0022]

[Chemical 11]

(Wherein Z ¹ , Z ² , Z ³ and Z ⁴ are the same or different and each represents H, CH ₃ , CONH ₂ or —C (N
H ₂ ) = NH is shown. In the above, M is the same as above, m
Represents an integer of 1 to 15. ) A compound represented by
(E) General formula

[0024]

[Chemical 12]

(In the formula, A is H, --OH, --SH, NH ₂
CO -, - COOM, amino, -NHC (NH ₂₎ =
_{NH, -ONH 2, -CH (NH} 2) CO 2 H, RS-,
NH ₂ CONH-,

[0026]

[Chemical 13]

Or

[0028]

[Chemical 14]

Wherein Z ⁵ , Z ⁶ and Z ⁷ are the same or different and each represents H, CH ₃ or C ₂ H ₅ , and Z ⁸ represents NH ₂ or OH. In the above, M is the same as above, R is C
_1-5 alkyl, 1 is an integer of 0 to 4, k is 0 or 1
Indicates. ), (F) a compound of general formula (IV) and / or a dipeptide or tripeptide compound condensed with a compound of general formula (V), and (g) a cyclic nitrogen compound.

The alkyl group shown in the above (b), (c), (e) and (f) is preferably one having 1 to 5 carbon atoms, specifically methyl, ethyl, propyl, Isopropyl, cyclopropyl, n-butyl, t-
Examples thereof include butyl, n-pentyl, isoamyl, neopentyl and the like. Examples of the aralkyl group or aralkenyl group shown in (b) above include benzyl, phenethyl, phenylpropyl, cinnamyl, furfuryl,
Examples thereof include naphthylmethyl, naphthylethyl, pyridylmethyl, pyridylethyl and quinolylmethyl. Examples of the aryl group shown in (b) above include:
Examples thereof include phenyl, tolyl, mesityl, 1 naphthyl, 2-naphthyl, pyridyl, quinolyl, quinoxalyl, anthraquinolyl, thiazolyl and furyl.

Preferred specific examples of the chelating agent used in the present invention are shown below.

Compound (a): ethylenediaminetetraacetic acid (EDTA), ethylenediaminetetraacetic acid disodium salt (EDTA.2Na), hydroxyethylethylenediaminetriacetic acid (HEDTA), diethylenetriaminepentaacetic acid (DTPA), triethylenetetraminehexaacetic acid (TT).
HA), ethylenediaminetetrapropionic acid, ethylenediaminetetramethylenephosphonic acid, diethylenetriaminepentamethylenephosphonic acid and the like.

Compound (b): Nitrilotriacetic acid (NT
A), iminodiacetic acid (IDA), iminodipropionic acid (IDP), aminotrimethylenephosphonic acid, aminotrimethylenephosphonic acid pentasodium salt, methylamine,
Ethylamine, propylamine, dimethylamine, trimethylamine, dimethylethylamine, benzylamine, 2-naphthylamine, isobutylamine, isoamylamine, methylenediamine, ethylenediamine, tetramethylenediamine, pentamethylenediamine, hexamethylenediamine, diethylenetriamine, tetraethylenepentamine, Pentaethylenehexamine, hexaethyleneheptamine, cinnamylamine, p-methoxycinnamylamine, ammonia and the like.

Compound (c): 1-hydroxyethylidene-1,1-diphosphonic acid, 1-hydroxyethylidene-
1,1-diphosphonic acid trisodium salt, citric acid, tartaric acid, malic acid, malonic acid and the like.

Compound (d): Glycine, alanine, N-
Methylglycine, glycosamine, dimethylglycine,
Hydantoic acid, aminovaleric acid, β-alanine and the like.

Compound (e): Valine, norvaline, leucine, norleucine, isoleucine, serine, cysteine, asparagine, aspartic acid, glutamic acid, ornithine, lysine, arginine, glutamine, diaminopropionic acid, citrulline, hydroxy-L-lysine,
Diaminobutyric acid, aminoadipic acid, kanaline, kynurenine, diaminopimelic acid, homocysteine, histidine, methionine, etc.

Compound (f): Aspartyl-histidine, alanyl-alanine, alanyl-β-alanine, β
-Alanyl-β-alanine, glycyl-lysine, alanyl-ornithine, lysyl-lysine, ornityl-ornithine, glycyl-ornithine, β-alanyl-lysyl-
Lysine, ornithyl-lysyl-lysine, glycyl-ornithyl-ornithine and the like.

Compound (g): imidazoline, 2,4,5
-Triphenyl-2-imidazoline, 2,2'-bis (2-imidazoline), pyridine, morpholine, bipyridyl, pyrazole, triazine and the like.

In the catalyst liquid of the present invention, the above (a) to
At least one chelating agent (g) may be used, and the compounding amount thereof is 0.001 to 6 mol / l in the catalyst liquid.
The degree is preferably about 0.01 to about 0.01, and more preferably 0.01 to
It is about 3 mol / l. If it is less than 0.001 mol / l, there is no effect of improving the stability of the catalyst solution, and if it exceeds 6 mol / l, it is uneconomical, which is not preferable.

The pH of the catalyst solution of the present invention is not particularly limited, but when the pH is adjusted, an acid such as HCl or H ₂ SO ₄ or an alkali compound such as NaOH is used if necessary. Good.

A nonionic, cationic, anionic or amphoteric surface active agent may be added to the catalyst solution, whereby the surface tension of the catalyst solution is lowered and the surface of the copper-based material is reduced. The catalytic activity of can be made uniform.

As the pH buffering agent, hydrochloric acid-potassium chloride, potassium hydrogen phthalate-hydrochloric acid, potassium hydrogen phthalate-sodium hydroxide, potassium dihydrogen phosphate-sodium hydroxide, boric acid-sodium hydroxide, hydrogen carbonate. Sodium-sodium hydroxide, disodium hydrogen phosphate-sodium hydroxide, sodium hydroxide-potassium chloride, tris (hydroxymethyl) aminomethane-hydrochloric acid,
Sodium acetate-acetic acid or the like can also be added. The surfactant and the pH buffer can be used alone or in an appropriate mixture as needed.

The catalyst solution of the present invention selectively activates a copper-based material for catalysts, and is suitable for a material such as a printed circuit board, a ceramic substrate, and a chip component in which an insulator and a conductor are integrated. It becomes possible to selectively catalytically activate only the base material and perform electroless plating only on the copper base material portion.

As the copper-based material to be applied, copper, brass, phosphor bronze, nickel silver, etc. can be mentioned, and these coppers can be formed by plating, vapor deposition, paste or the like on the material itself or various substrates. It can be applied to those with a coating of a system material.

The treatment method with the catalyst solution of the present invention may be the same as the treatment with an ordinary catalyst solution, and the solution temperature is about 10 to 90 ° C.
Preferably, the object to be treated may be immersed in the catalyst solution at about 25 to 70 ° C. for about 10 seconds to 10 minutes. If the liquid temperature is too low, the skip phenomenon easily occurs. On the other hand, if the liquid temperature is too high, the working environment deteriorates, so care must be taken.

After activation by the catalyst solution, electroless plating is performed to selectively form a plating film on the copper-based material. The catalyst solution of the present invention is not particularly limited as an electroless plating solution, but is particularly effective when an electroless plating solution such as Ni, Pd, Pd-Ni using a hypophosphorous acid compound as a reducing agent is used. .

When the catalyst solution of the present invention is used, pretreatments such as degreasing and pickling may be carried out according to conventional methods, and electroless plating conditions may be usual.

[0048]

EFFECTS OF THE INVENTION By using the catalyst solution of the present invention, it is possible to selectively perform electroless plating only on a copper-based material, and a material consisting of an insulator and a conductor such as a printed circuit board, a ceramic substrate, and a chip part. Against the skip phenomenon,
It is possible to form a good plating film only on the conductor portion without causing a bridge phenomenon or the like. Further, the catalyst liquid of the present invention uses nickel or cobalt as the catalyst metal, and is more cost effective than the conventional catalyst liquid containing palladium as the catalyst metal.

[0049]

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

[0050]

[Example 1] A hole was drilled in a glass epoxy copper clad laminate,
After performing electroless copper plating and electrolytic copper plating, an etching resist layer is formed, and then etching, etching resist layer peeling, solder resist printing, character printing,
The following treatment was performed on a 100 × 170 × 16 mm copper-plated through-hole printed wiring board for mixed mounting of double-sided surface mounting components and single-sided insertion type components obtained through the outer shape processing step.

After the printed wiring board is immersed in degreasing and pickled,
60 g of ammonium persulfate aqueous solution at 30 ℃
After soaking for 2 seconds to perform soft etching, and then pickling, a catalyst was applied under the catalyst liquid composition and conditions shown in Table 1. Then, with the following composition and conditions, Ni, Pd, Pd-N
Each electroless plating of i was conducted to examine whether or not the skip phenomenon and the bridge phenomenon occurred. In the case of evaluating the skip phenomenon, the plating time was 30 seconds, and in the case of evaluating the bridge phenomenon, the plating time was 30 minutes.

Electroless Ni plating solution Nickel sulfate (hexahydrate) 20 g / l Malic acid 20 g / l Sodium hypophosphite (monohydrate) 30 g / l Lead acetate (trihydrate) 1 mg / l pH (ammonia water 6 bath temperature 85 ° C. deposition rate approximately 8 μm / h electroless Pd plating solution palladium chloride 0.01 mol / l ethylenediamine 0.08 mol / l thiodiglycolic acid 20 mg / l sodium hypophosphite 0.06 mol / L pH 8 Bath temperature 50 ° C Deposition rate Approximately 1 µm / h Electroless Pd-Ni plating solution Palladium chloride 0.01 mol / l Nickel chloride 0.1 mol / l Ethylenediamine 0.08 mol / l Thiodiglycolic acid 20 mg / l Sodium hypophosphite 0.06 mol / l pH 8 Bath temperature 50 ° C. Deposition rate approx. 2 μm / h

[0053]

[Table 1]

As a result of the above test, No. When the catalyst solutions 1 to 8 are used, the substitution reaction between the copper-based material and nickel or cobalt does not occur. Therefore, if electroless plating of Ni, Pd and Pd-Ni is performed thereafter, all the plating solutions In many cases, no plating phenomenon or skip phenomenon was observed.

On the other hand, the catalyst liquid of the present invention No. 9-36
When the catalyst solution of No. 2 was used, a good plating film could be formed only on the copper plating film, and no plating phenomenon, skip phenomenon and bridge phenomenon were observed at all.

[0056]

Claims (2)

[Claims] 1. At least one of (I) a nickel compound and a cobalt compound, 0.001 to 3 mol / l, and (I)
I) At least one kind of thiourea 0.05 to 5 mol / l
A copper-based material selection type electroless plating catalyst liquid, which comprises an aqueous solution containing 2. (a) General formula: (In the formula, X ¹ , X ² and X ³ are the same or different;
_{CH 2 CO 2 M, -CH 2} PO 3 MM, -CH (CH 3) C
O ₂ M or -CH ₂ CH ₂ CO ₂ shows the M, X ⁴ is -CH ₂ C
_{O 2 M, -CH 2 PO 3} MM, -CH 2 CH 2 OH, -CH
(CH ₃₎ CO ₂ M or indicates -CH ₂ CH ₂ CO ₂ M,
X ⁵ is _{H, -CH 2 CO 2 M,} -CH 2 PO 3 MM, -CH
(CH ₃₎ shows the CO ₂ M or -CH ₂ CH ₂ CO ₂ M. In the above, M is the same or different and is H, K or N, respectively.
a or NH ₄ and n is an integer of 0 to 2), (b) a compound represented by the general formula: (In the formulae, X ⁶ and X ⁷ are the same or different and each represents H, C or
_1-5 alkyl, aralkyl, aralkenyl, aryl,
_{-CH 2 CO 2 M, -CH (} CH 3) CO 2 M, -CH 2 C
H ₂ CO ₂ M, shows a -CH ₂ PO ₃ MM or -CH ₂ CH ₂ OH, X ⁸ is, H, C _1-5 alkyl, aralkyl, _{aryl, -CH 2 CO 2 M, -CH} (CH 3 ) CO ₂ M, -CH
_{2 CH 2 CO 2 M, -CH} 2 PO 3 MM, -CH 2 CH 2 O
_{H, - (CH 2) p} -NH 2 or - [(CH _{2) q} -NH] _r
Indicates -H. In the above, M is the same as above, P is 0 to
An integer of 10, q is an integer of 1 to 3, r is an integer of 1 to 10), and (c) is a compound represented by the general formula: (In the formula, X ⁹ represents H, —CH ₂ CO ₂ M or —PO ₃ MM, and X ¹⁰ is C _1-5 alkyl, —CO ₂ M or —CH ₂ CO ₂
Indicates M, X ¹¹ is _{-CO 2 M, -CH 2 CO 2} M, -PO 3
MM or —CH (OH) CO ₂ M is shown, and X ¹² is H or OH. In the above, M is the same as defined above, and (d) the general formula: (In the formula, Z ¹ , Z ² , Z ³ and Z ⁴ are the same or different and each represents H, CH ₃ , CONH ₂ or —C (NH ₂ ) ═NH. In the above, M is the same as above, m Represents an integer of 1 to 15), and (e) the general formula: (In the formula, A _{H, -OH, -SH, NH 2} CO -, - C
OOM, amino _{group, -NHC (NH 2) = NH} , -ON
_{H 2, -CH (NH 2)} CO 2 H, RS-, NH 2 CONH
-, Or And Z ⁵ , Z ⁶ and Z ⁷ are the same or different and each represents H,
CH ₃ or C ₂ H ₅ is shown, and Z ⁸ is NH ₂ or OH.
In the above, M is as defined above, R is C _1-5 alkyl, l is an integer from 0 to 4, and k is 0 or 1. ), A compound (f) of the general formula (IV) and / or a dipeptide or tripeptide compound condensed with the compound of the general formula (V), and (g) at least one chelate selected from a cyclic nitrogen compound. Agent 0.001 to 6 mol /
The copper-based material selection type electroless plating catalyst liquid according to claim 1, further containing 1 l.