JPH10245693A - Electroplating bath for nickel and nickel alloy and electroplating method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent corrosion of electronic parts and to prevent precipitation of metals on an insulating part even when the current density is increased, by incorporating a heterocyclic quaternary ammonium compd. as a brightener into a nickel or nickel alloy electroplating bath. SOLUTION: The nickel or nickel alloy electroplating bath consists of a nickel salt or a nickel salt and a water-soluble salt of one or more elements selected from boron, cobalt, copper, iron, manganese, phosphorus, tin and zinc, and a brightener comprising a quaternary ammonium compd. expressed by formulae I to V. In formulae I to V, R1 is 6 to 18C alkyl group, R2 , R3 are -H, -CH3 , -C2 H5 , -OH, -OCH3 , -OC2 H5 , -HN2 , -NO2 -COOH, -SO3 H, X is at least one of halogen ions, CH3 SO4 <-> , C2 H5 SO4 <-> , CH3 COO<-> and NO3 <-> . The pH of the plating bath is controlled to 3 to 10. The brightner is preferably added by about 0.01 to 1g/l.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a nickel or nickel alloy electroplating bath used in a plating process for electronic parts, and a method for electroplating the bath.

[0002]

2. Description of the Related Art Normally, electronic parts made of ceramic, glass, plastic or the like are plated with tin or tin alloy for the purpose of improving the solder wettability of the electrodes. For the purpose of preventing solder erosion and whiskers, the base is plated with nickel or a nickel alloy.

At this time, various problems occur which do not occur when plating metal.

For example, when a chip component using glass or ceramic material is plated using a chloride bath having a pH of about 2.0, the glass or ceramic undergoes significant erosion or a pH of about 4.0. When plating is carried out using a Watt bath or a sulfamic acid bath, there is a phenomenon that glass or ceramic which is originally an insulator is plated, although erosion of glass or ceramic is not observed.

In order to cope with such a problem, when plating this kind of component, a countermeasure has been taken so far that a plating current is extremely reduced by using a nickel or nickel alloy bath of pH 4 to pH 6.

[0006]

However, making the plating current extremely small leads to the following various problems (a) to (c). (A) Deterioration of productivity due to prolonged plating time (a) Deterioration of component characteristics due to prolonged immersion (c) Non-deposition of plating generated on a part of the electrode The present invention has been made in view of the above problems. That
An object of the present invention is to provide a nickel or nickel alloy electroplating bath and a method for electroplating the same, in which metal is not deposited on an insulator portion even when an electronic component is not eroded and a current density is increased. I do.

[0007]

The present invention solves the above problems.
Nickel or nickel alloy electroplating bath to solve
And the electroplating method was completed. Application
The nickel or nickel alloy electroplating bath of the first invention is
(1) Nickel salt or nickel salt, boron, edge
From copper, iron, manganese, phosphorus, tin, and zinc
A water-soluble salt of at least one element, and (2) a brightener
Quaternary represented by any of the above general formulas [A] to [S]
Ammonium compounds (provided that R ₁Has 6 to 18 carbon atoms
Alkyl group, R_Two, R_ThreeIs -H, -CH_Three, -C_TwoH_Five, −
OH, -OCH_Three, -OC_TwoH_Five, -NH_Two, -NO_Two, −
COOH, -SO_ThreeH and X are halogen ions, CH_ThreeSO
_Four ^-, C_TwoH_FiveSO_Four ^-, CH_ThreeCOO^-, NO_Three ^-Less of
And (3) pH 3 to pH 10.
It has special features.

[0008] Further, the method for electroplating nickel or nickel alloy of the second invention of the present application is characterized in that an electronic component is electroplated using the above-mentioned nickel or nickel alloy electroplating bath.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The nickel or nickel alloy electroplating bath according to the first invention of the present application can achieve the object of the present invention by the above-mentioned configuration for the following reasons. That is, the following phenomena (1) and (2) were ascertained, and as a result of further study on the brightener, the fourth agent represented by the above general formula that satisfies (a) and (b) was obtained. It has been found that by adding a quaternary ammonium compound to a nickel or nickel alloy electroplating bath at pH 3 to pH 10, metal deposition on the insulator is significantly suppressed.

(1) Elution of ceramic and glass, which are constituent materials of electronic parts, greatly depends on pH, and particularly, pH 2
It becomes remarkable in the region below or pH10 or more. (2) Deposition of metal on the insulator portion is more likely to occur as the erosion of the insulator portion increases, and the deposition state also differs significantly depending on the type of brightener.

(A) A 5- or 6-membered heterocyclic structure containing a nitrogen atom. (B) The alkyl group bonded to the nitrogen atom has 6 to 1 carbon atoms.
Being a bulky group of 8.

Although the detailed mechanism by which the brightener shown in the first invention of the present application effectively acts on the above-mentioned problem as a surfactant is not clear, it may have the following structure (1) or (2). It is thought that this is acting to suppress the metal deposition. (1) The alkyl group represented by R ₁ has a certain size (in the case of a straight chain, it has 8 or more carbon atoms, and in the case of a cyclic structure, it has 6 or more carbon atoms). (2) R ₂ , so that the nitrogen atoms can approach the plating object and the surfactants can be closely packed and adsorbed.
The side chain group represented by R ₃ is a functional group having a small molecular weight.

The alkyl group represented by R ₁ has 6 to 6 carbon atoms.
18, preferably 12 to 16, which may be straight-chain, branched or cyclic. When the carbon number is less than 6, the inhibitory effect is lost, and when the carbon number is more than 18, water solubility is lost.

The side chain groups represented by R ₂ and R ₃ do not impair the inhibitory effect as long as they have a small molecular weight. However, as the molecular weight increases, the inhibitory effect gradually decreases.

Next, regarding the amount of the brightener added, if added in a large amount, reductive decomposition becomes active and management in the process becomes complicated.
g / l, more preferably 0.01 to 0.5 g / l.

The basic bath to which the brightener is to be added has a pH of 3 to p due to the following reasons (1) and (2).
There is no particular limitation as long as it is within the region of H10. (1) Erosion of glass or ceramics is more affected by bath pH than bath composition. (2) Metal deposition on glass and ceramics is suppressed by the brightener shown by the present invention.

Next, the present invention will be described more specifically based on examples, but the present invention is not limited to only these examples.

[0018]

EXAMPLES Table 1 shows sample Nos. No. 1 to No. 1 14 shows the composition, pH, and bath temperature (° C.).

[0019]

[Table 1]

Using a plating bath composed of the samples shown in Table 1, a current density (A / dm ² ) and a plating time (min) were applied to a 5 × 5 mm nickel veneer baked with lead glass (3φ).
And plating was performed. Table 2 shows the erosion state of the lead glass and the manner of plating on the lead glass at that time.

In Table 2, among the erosion of the glass parts, the one indicated by ○ indicates that no evidence of erosion was observed on the appearance, and the one indicated by △ was slightly eroded on the appearance. A mark indicates a state where a trace is observed, and a cross indicates a state where a trace of erosion is remarkably recognized in appearance. Also, in the plating of the glass part in Table 2, the symbol “○” indicates a state in which almost no metal deposition was observed on the glass, and the symbol “△” indicates a state in which slight metal deposition was observed on the glass. The symbol x indicates a state in which remarkable metal deposition on the glass is observed.

[0022]

[Table 2]

As is clear from Table 2, in the acidic bath (chloride bath) of pH 2 shown in Sample 12, when the erosion time is long, erosion of the glass portion and deposition of metal on the glass portion are observed. On the other hand, sample 13 (watt bath), sample 1
In a weakly acidic bath such as 4 (sulfamic acid bath), erosion of the glass part is suppressed, but when the current density is increased, metal deposition on the glass part is observed.

On the other hand, in the case of the baths shown in Samples 1 to 11, neither erosion of the glass portion nor deposition of metal on the glass portion is observed even when the current density is increased.

[0025]

According to the present invention, it is possible to prevent metal deposition on the insulator portion even when the electronic component is not eroded and the current density is increased.

 ──────────────────────────────────────────────────の Continued on the front page (72) Inventor Masanori Endo 2-26-10 Tenjin, Nagaokakyo-shi, Kyoto Inside Murata Manufacturing Co., Ltd.

Claims (2)

[Claims] 1. A nickel or nickel alloy electroplating bath having the following constitution. (1) Nickel salt or water-soluble salt of nickel salt and one or more elements selected from boron, cobalt, copper, iron, manganese, phosphorus, tin and zinc (2) Brightener A quaternary ammonium compound represented by any one of [A] to [S]; General formula [B] General formula [C] General formula [D] General formula [E] General formula [F] General formula [G] General formula [H] General formula [I] General formula [J] General formula [K] General formula [L] General formula [M] General formula [N] General formula [O] General formula [P] General formula [Q] General formula [R] General formula [S] (However, R ₁ is an alkyl group having 6 to 18 carbon atoms, R ₂ , R
_{3 -H, -CH 3, -C 2 H} 5, -OH, -OCH 3, -
_{OC 2 H 5, -NH 2,} -NO 2, -COOH, -SO
₃ H and X are halogen ions, CH ₃ SO ₄ ⁻ , C ₂ H ₅ S
At least one of O ₄ ⁻ , CH ₃ COO ⁻ , and NO ₃ ⁻ ) (3) pH 3 to pH 10 2. A method for electroplating nickel or a nickel alloy, comprising: electroplating an electronic component using the nickel or nickel alloy electroplating bath according to claim 1.