JPS62103387A - Electroplating liquid - Google Patents

Abstract

PURPOSE:To provide an electroplating liquid with which plating films of Ni, Co, Fe, etc. having an excellent uniform electrodeposition characteristic are obtd. by incorporating a water soluble salt of Ni, Co, Fe, etc. into the liquid and incorporating an adequate amt. of a buffer consisting of a specific conductive salt and specific water soluble compd. CONSTITUTION:This electroplating liquid is formed by contg. the water soluble salt of the metal selected from Ni, Co and Fe, contg. at least one kind among a water soluble halide, sulfate and sulfamate of the metal selected from an alkali metal, alkaline earth metal and Al as the conductive salt at a high concn. of 150-800g/l, and contg. >=1 kinds among an org. carboxylic acid and the salt thereof, ammonium hydroxide, ammonium salt and amine as the buffer. The above-mentioned electroplating liquid has the excellent uniform electrodeposition characteristic, yields the plating films of Ni, Co and Fe or the alloy thereof and is suitable for electroplating of materials having intricate shapes.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to an electroplating solution capable of providing a plating film with excellent uniform electrodeposition of nickel, cobalt, iron, or an alloy thereof.

Conventional techniques and problems to be solved by the invention Conventionally, as nickel and nickel alloy electroplating solutions, Watt bath, Wisevelve bath, high nickel sulfate bath, high chloride bath, nickel sulfamate bath, etc. have been known. All of these baths have problems with uniform electrodeposition, and corrosion resistance, gloss, and leveling deteriorate due to insufficient film thickness in low current density areas.

On the other hand, problems arise, such as an increase in plating time to ensure film thickness in low current density areas, a decrease in dimensional accuracy of plated products due to excessive electrodeposition in high current density areas, and wasteful consumption of plated metal. Especially recently, plating for etching resist of printed circuit boards, terminal plating, IC, LS
Nickel plating or nickel-cobalt alloy plating is widely used as a gold plating base for I wiring, lead frames, etc., but when used for these platings, as mentioned above, uniform electrodeposition is required. The coating strength in the low current density area is poor, resulting in poor bonding and soldering, and poor corrosion resistance.To prevent this, increasing the plating thickness in the low current density area will cause the plating thickness in the high current density area to increase. This has disadvantages such as increased stress, increased stress, and poor adhesion, which has been a major problem in the manufacture of IC1LSIs and the like. Furthermore, when plating plastic or zinc die-cast products or packaging for EMI (electromagnetic interference) prevention, these products often have complex shapes, so poor gloss in low current density areas and EMI There were problems such as a decline in prevention ability.

In this case, chemical plating may be used to make the plating thickness uniform, but chemical plating has a slow plating speed and requires a metal ion reducing agent, which increases plating costs. In addition, the types of metals and alloys that can be chemically plated are currently limited, and since metal ions are usually complexed, wastewater treatment requires time and effort.

Therefore, there has been a desire for electroplating solutions for nickel, cobalt, iron, and alloys thereof that have excellent uniform electrodeposition properties.

The present invention was made in view of the above circumstances, and an object of the present invention is to provide an electroplating solution capable of producing a nickel, cobalt, iron, or alloy plating film having excellent uniform electrodeposition properties.

As a means to solve the problem, the present inventor has conducted extensive research into improving the uniform electrodeposition properties of plating films made of nickel, nickel alloys, etc., and as a result, has developed a method for improving the uniform electrodeposition of plating films made of nickel, nickel alloys, etc. At least one of water-soluble halides, sulfates, and sulfamates of a metal selected from alkali metals, alkaline earth metals, and aluminum is added in a plating solution using a water-soluble salt as an ion source for the metal to be plated at a concentration of 150 g/ Q
above, more preferably at a high concentration of 200 g/Q or more, and one or more water-soluble buffers selected from organic carboxylic acids and their salts, ammonium hydroxide, ammonium salts, and amines. It has been found that when the compound is added, the uniform electrodeposition property is significantly increased. In this case, for example, the Watts bath is NiSO4.6H2
A normal nickel sulfamate bath contains about 300 g/l of nickel sulfamate.
Although plating solutions containing 300 g/Q of N1cQ2.6H20 have been known as high nickel chloride baths, these are poor in uniform electrodeposition as described above. However, sulfate ions, halogen ions, or sulfamate ions are not provided as sulfates or halides of Ni, Co, Fe, etc.

Provided in high concentration as a sulfate, halide, or sulfamate of alkali metals, alkaline earth metals, or aluminum, and used as a buffering agent selected from organic carboxylic acids and their salts, ammonium hydroxide, ammonium salts, and amines. It has been found that when a species or two or more water-soluble compounds are added, the uniform electrodeposition property is significantly increased, and when sulfuric acid or hydrochloric acid is added, the uniform electrodeposition property is further increased. The present invention was based on the discovery that adding a compound, a hydrazine compound, phosphorous acid, hypophosphorous acid, or a salt thereof imparts features such as obtaining a highly hard plating film. .

The present invention will be explained in more detail below.

The plating solution according to the present invention contains a water-soluble salt of a metal selected from nickel, cobalt, and iron, and a water-soluble halide of a metal selected from alkali metals, alkaline earth metals, and aluminum as a conductive salt, and sulfuric acid. at least one of a salt and a sulfamate, from 150 to 800
g/Q.

Here, the water-soluble metal salts include Ni and Fe.

There is no particular restriction as long as it is a water-soluble salt of Co. For example, Ni
, Fe, Go sulfates, sulfamates, halides, etc., specifically nickel sulfate, ferrous sulfate, cobalt sulfate, nickel bromide, nickel chloride, ferrous chloride, cobalt chloride, nickel sulfamate, Examples include ferrous sulfamate, cobalt sulfamate, etc., and these metal salts have a content of 5 to 400 g/l, particularly 5 to 200 g/l,
More preferably it can be used at a concentration of S~100 g/Q. In this case, even if the concentration of these metal salts is low, according to the present invention, moss is unlikely to occur and uniform electrodeposition can be improved. When obtaining an alloy plating film, two or more of the above water-soluble metal salts or the above water-soluble metal salts are used as a main component, and in addition, tungstic acid and its salts, molybdic acid and its salts, zinc sulfate, zinc chloride, etc. Select and use water-soluble salts of the desired metals to be alloyed with Ni, Fe, and Co, such as zinc metal salts, copper metal salts such as copper sulfate and copper chloride, and tin metal salts such as tin sulfate and tin chloride. can do. In addition, the concentration of these metal salts to be alloyed is selected appropriately depending on the alloy composition, but is usually 1 to 100%.
g/Q, especially in the range from 1 to 50 g/Q.

In the present invention, halides, sulfates, and sulfamic acids of metals selected from alkali metals, alkaline earth metals, and aluminum are used as conductive salts in a plating solution that uses the water-soluble metal salts as ion sources for metals to be plated. salt 1
Add a seed or two or more. Specifically, petrified lithium, sodium chloride, potassium chloride, aluminum chloride, ammonium chloride, magnesium chloride, sodium bromide, potassium bromide, lithium sulfate, sodium sulfate, potassium sulfate, aluminum sulfate, sodium sulfamate,
Examples include potassium sulfamate.

The amount of these conductive salts used must be 150 to 800 g/l, and high uniformity of electrodeposition can be achieved by using these conductive salts at a high concentration of 150 g/l or more. On the other hand, if the blending amount is less than 150 g/l, the effect of improving uniform electrodeposition is poor and the object of the present invention cannot be achieved. In addition, the more preferable amount of the conductive salt used is 200 to 500 g/Ω.

In addition to the above components, the plating solution of the present invention further contains organic carboxylic acids and their salts, ammonium hydroxide,
One or two selected from ammonium salts and amines
In this method, more than one type of water-soluble compound is added. Here, the above buffering agents include malic acid, ammonium malate,
Succinic acid, ammonium succinate, potassium acetate, sodium acetate, ammonium tartrate, ascorbic acid, citric acid, ammonium citrate, lactic acid, pyruvic acid, propionic acid, butyric acid, formic acid, acetic acid, glycolic acid, oxalacetic acid, aqueous ammonia, ethylenediamine , triethanolamine, ethanolamine, ammonium chloride, ammonium bromide, and the like. Among these, carboxylic acids and salts thereof, particularly citric acid and salts thereof are preferred, and ammonium salts are preferred as the salts. Triammonium citrate is particularly effective in terms of plating appearance and physical properties (low stress, flexibility). The amount used is not necessarily limited, but when using carboxylic acids and their salts, it is 5 to 300 g/Q, especially 10 to 200 g/l.
It is preferable that In addition, when using ammonium hydroxide, ammonium salts other than ammonium carboxylate, and amines, 10 to 100 g/Q, especially 10 to
It is preferable to set it as 50 g/Q. In this case, the Ni, Fe.

The weight ratio of Co ions and these buffers is 1:
A ratio of 1 to 1:5 is preferable from the viewpoint of further improving uniform electrodeposition. In addition, when using ammonium carboxylate, the concentration of Ni, Fe, and Co ions is 5 to 100 g.
/ Q, especially at a low concentration of about 5 to 60 g / Q, good plating without burning is performed, and uniform electrodeposition can be further improved, so Ni, Fe,
It is preferable that the Co ion concentration is set to the above-mentioned low concentration.

Furthermore, hydrochloric acid or sulfuric acid can be added to the plating solution of the present invention, thereby improving uniform electrodeposition. The amount used is 0.1-30g/l, especially 1-3g/l.
It is preferable to set it to 1.

In this case, it is preferable to set the concentration of the water-soluble salts of Ni, Fe, and Co to a low concentration of 5 to 1 OOg/Q in order to obtain a plating film with high uniformity of electrodeposition.

The plating solution of the present invention contains hypophosphorous acid, phosphorous acid, salts thereof, amine borane compounds, and hydrazine compounds.
Approximately 100 g/Q can be added, and thereby a phosphorus-containing or boron-containing plating film can be obtained. Such a phosphorus- or boron-containing plating film becomes a hard film with a micro-Vickers hardness of Hv500 to 800, and a film with even higher hardness can be obtained by heat treatment in the same manner as the chemical nickel plating film. In addition, the boron-containing alloy plating film exhibits excellent solderability, bonding properties, heat resistance, and wear resistance.

Furthermore, the electroplating solution of the present invention contains additives commonly used as additives such as brighteners and leveling agents, such as saccharin, sodium naphthalene disulfonate, sodium naphthalene trisulfonate, sodium allylsulfonate, and propargyl sulfonate. Appropriate amounts of sodium acid, butynediol, propargyl alcohol, coumarin, formalin, etc. can be added.

The pH of the plating solution of the present invention is preferably 1 to 12, particularly 1 to 10, and may be used in any of acidic, neutral, and alkaline baths, but the effects of the present invention are particularly effective in acidic plating. Demonstrate.

When plating using the plating solution of the present invention, the plating conditions may be the same as those for known Ni, Fe, Co, or alloy plating; for example, the plating temperature is 10 to 7
Conditions of 0° C. and a cathode current density of 0.01 to 50 A/dm may be adopted. If necessary, stirring may be performed by air stirring, cathode rocking, liquid circulation using a pump or the like, propeller stirring, or the like. The anode is selected depending on the type of plating solution, such as electrolytic nickel, sulfur-containing nickel, carbonized nickel, iron,
A soluble anode such as a cobalt or alloy anode is used, and in some cases an insoluble anode such as platinum or carbon may also be used.

Note 1: When plating using the plating solution of the present invention, setting the current efficiency to 60 to 100% can achieve high uniformity of electrodeposition and increase the thickness of the plating film in low current density areas. preferred.

There are no restrictions on the material of the product to be plated using the plating solution of the present invention, and any material that can be electroplated can be plated, such as metals, conductive plastics,
Ceramic etc. are plated. These can be plated using the plating solution of the present invention after being subjected to a known pretreatment and a desired base plating, or after plating with the plating solution of the present invention, chrome plating or gold plating can be applied thereon. Known post-treatments such as plating and other types of plating can be performed.

The electroplating solution according to the present invention contains a water-soluble salt of a metal selected from nickel, cobalt, and iron, and a water-soluble halide of a metal selected from alkali metals, alkaline earth metals, and aluminum; Contains 150 to 800 g/+2 of at least one of sulfate and sulfamate, and further contains one or more buffering agents selected from organic carboxylic acids and their salts, ammonium hydroxide, ammonium salts, and amines. By containing the water-soluble compound, it is possible to obtain a plating film which is excellent in uniform electrodeposition and has a small difference in film thickness between the high 6Jε density part and the low current density part.

Therefore, the plating solution of the present invention is suitable for electronic components (etching resist plating for printed circuit boards, terminal plating, IC, L
SI wiring, lead frames, etc.), molds, printed wiring boards, sliding parts, plating on electroformed products, barrel plating, plastics with complex shapes, electromagnetic interference prevention packages, metal coatings on porous materials. , Suitable for use in alumite dyeing plating, etc.

The present invention will be specifically explained by showing examples below, but the scope of the present invention is not limited thereto.

[Example 1 NiSO4・6H2020g/l NiCQ□・6H2020' NaCQ, 300' Citric acid 20' Concentrated sulfuric acid
1.5 mQ/l pH 1 When plating was carried out using the above electroplating solution at a temperature of 55°C and a cathode current density of 2 A/dm with air stirring, the appearance was very similar to that obtained from a Watt bath. A Ni plating film was obtained.

[Example 2 N iS O4・6 I4 z O20g / QN
iCQ z・6H,020' KCQ 300 'Sodium citrate 40' pH 3 When plating was performed using the above electroplating solution at a temperature of 55°C and a cathode current density of 2A/d112 under air agitation, a silvery white glossy state was obtained. A flexible Ni plating film was obtained.

[Example 3] Nickel sulfamate 40 g/QNa
, So, 250'NaCQ
30'malic acid
40' ammonia water
60 mA/np H6 Using the above electroplating solution, plating was carried out at a temperature of 55°C and a cathode current density of 2 A/dm'' with air agitation. A certain Ni plating film was obtained.

[Example 4 N1CQ, 6 Hz 0 40 g /
12Kcm 300 7NH,
CQ 60 “H, Bo,
10' pH 3.5 When plating was carried out using the above electroplating solution at a temperature of 55°C and a cathode current density of 2 A/dm2 with air agitation, a dark, matte and flexible Ni plating film was obtained. It was done.

[Example 5 N1CQ, -6H, 0100 g/l KCQ 270 'Triammonium citrate 15' pH 5,0' Using the above electroplating solution, at a temperature of 55°C and a cathode current density of 2 A/dm2 under air stirring. When plating was performed, a brownish gray and matte Ni plating film was obtained.

[Example 6] NiSO4.6 H2050g/QLICQ
300' succinic acid
4o 'Ammonia water
70 m Q/n dimethylamine borane
Ig/Fl H6 When plating was performed using the above electroplating solution at a temperature of 55°C and a cathode current density of 2 A/dm2 with air stirring, a completely glossy N1-B alloy plating was obtained.

[Example 7 N15O, 6H, 060g/l KCQ 250'Succinic acid 40'Ammonia water
70 m Q/Q Sonnous acid
50g/l concentrated sulfuric acid 1.5mQ
/l H2 When plating was performed using the above electroplating solution at a temperature of 55° C. and a cathode current density of 2 A/dm” with air stirring, a completely glossy N1-P alloy plating was obtained.

[Example 8 N15o4・6I(,o 20g/lN
iCρ2.6H2030' Na, So4 300' Triammonium citrate 10'' Sodium saccharin 2'p) (4,8 Plating using the above electroplating solution at a temperature of 55 °C and a cathode current density of 2 A/dm2 under air stirring When this was carried out, a completely glossy N1 plating was obtained.

[Example 9] N1CQ2・6H, 040g/l Sodium molybdate 10'KCQ
250 “Succinic acid
40' ammonia water
70 m Q / Q pH 10 When plating was performed using the above electroplating solution at a temperature of 55 °C and a cathode current density of 2 A / dm2 with air stirring, a semi-glossy Ni-Mo alloy plating film was obtained. .

[Example 10 CO3O4.7H2050g/l KBr 300'triammonium citrate 10'PI (4,8) Plating was carried out using the above electroplating solution at a temperature of 55°C and a cathode current density of 2A/dm2 with air stirring. When done, C was matte and flexible.

A plated film was obtained.

[Example 11] F e S 04 ・ 7 g ■ 20
40 g/QNa
Br250
"Ammonium acetate 20'pi (
3,5 When plating was performed using the above electroplating solution at a temperature of 55°C and a cathode current density of 2 A/dm2 with air stirring, a matte and flexible Fe plating film was obtained.

[Comparative Example 1 NiSO4.6H20280g/l NiCI2.・5H2045#)i3B03 40'pH4,
4 Using the above electroplating solution, plating was performed at a temperature of 55° C. and a cathode current density of 2 A/d+n2 with air stirring to obtain a Ni plating film.

[Comparative Example 2] Ni sulfamate 300g/l NIC
Q2・6H2030'H,B○3 40'pH4,4 Using the above electroplating solution, plating was performed at a temperature of 55°C and a cathode current density of 2A/dm2 with air stirring,
Ni plating coating was obtained.

[Comparative Example 3] NiS O4・68.0 280 g/Q
NICQ2・6H2040" CoS O4.7 N20 35" Sodium formate 25'H, BO340
,,H4,2 Using the above electroplating solution, plating was performed at a temperature of 55°C and a cathode current density of 2 A/dm2 with air stirring to obtain a Ni-Co alloy plating film.

[Comparative Example 4 N1CQ, 6H20300g/l H3B0. 35'pH4,
2 Using the above electroplating solution, conduct plating at a temperature of 55°C and a cathode current density of 2A/dm2 with air stirring,
A N1 plating film was obtained.

Further, the electroplating solutions of Examples 1 to 11 and Comparative Examples 1 to 4 were examined for uniform electrodeposition using an improved burring cell manufactured by Sansui Nikin Shikenki Co., Ltd. as a plating tester. In this case, the anode is an electrolytic nickel plate, and the cathode is a 61xlOOx0.3 plate with tape coating on the back side.
Two mm-sized copper plates were used at a distance ratio of 1:5, the electroplating solution was kept at a solution temperature of 55° C., and a total current of 2 A was applied for 30 minutes while gently stirring the air. The uniform electrodeposition property (T (%)) of the obtained plating was calculated by weighing the weight of the plating film deposited on the cathode and according to the following formula.

P+M-2 However, T: Uniform electrodeposition P: Distance ratio (5 in this experiment) M: Weight ratio of plating film deposited on the cathode Table 1 Uniform electrodeposition 81! 1 Determination Results From the above results, the conductive salt according to the present invention was used at a concentration of 150 to 800 g/Q.
, and an electroplating solution containing the buffer according to the present invention (
Example) does not contain these conductive salts, and therefore, compared to the electroplating solution (comparative example) that does not contain both the conductive salt according to the present invention and the buffer according to the present invention, the plating film is improved. It was confirmed that uniform electrodeposition was much better.

Claims (1)

[Claims] 1. Contains a water-soluble salt of a metal selected from nickel, cobalt, and iron, and also contains an alkali metal as a conductive salt.
Contains 150 to 800 g/l of at least one of water-soluble halides, sulfates and sulfamates of metals selected from alkaline earth metals and aluminum, and as buffering agents organic carboxylic acids and their salts, ammonium hydroxide, An electroplating solution comprising one or more water-soluble compounds selected from ammonium salts and amines. 2. 0.1-30g of H_2SO_4 and/or HCl
The electroplating solution according to claim 1, wherein the electroplating solution is added in an amount of /l. 3. The electroplating solution according to claim 1 or 2, to which an amine borane compound, a hydrazine compound, phosphorous acid, hypophosphorous acid, or a salt thereof is added.