KR101476601B1 - Nickel electroless plating solution and electronic component using same - Google Patents

Abstract

Electroless nickel (or nickel-phosphorus) plating solution and electronic parts using the same are disclosed. The electroless nickel plating solution according to an embodiment of the present invention further comprises tetraethylenepentamine in an electroless nickel alloy plating solution containing a water soluble nickel salt, a reducing agent, a stabilizer, a complexing agent and a pH adjusting agent.

Description

TECHNICAL FIELD [0001] The present invention relates to an electroless nickel plating solution and an electronic component using the electroless nickel plating solution.

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a plating solution and an electronic component using the same. More particularly, the present invention relates to an electroless nickel plating solution improved in bending resistance and an electronic component using the same.

Generally, a printed circuit board has a surface treatment portion composed of a wire bonding portion and a soldering portion for mounting a semiconductor component.

The surface treatment portion is usually made of copper because copper has a low resistance against electric movement to improve the reliability of a semiconductor device and the like. In addition, since the resistivity is a half of that of aluminum, Can be increased.

However, copper exposed to the outside has a disadvantage that it is easy to oxidize the surface since the passivation effect of the surface oxide film is not large. That is, in the case of copper used for the surface treatment portion, since it is likely to be oxidized and corroded with the lapse of time, there is a risk that the soldering and wire bonding characteristics are not damaged by the corrosion, / Gold plating, nickel-phosphorus / palladium (or palladium-phosphorus alloy) / gold plating is formed to a thickness of 0.1 to 10 mu m to constitute the surface treatment portion.

 However, in the case of a flexible printed circuit board in which the flexible printed circuit board must be bent or deformed to a predetermined degree when the electronic component is manufactured or used, the conventional surface treatment unit can not properly cope with the deformation, Is shortened.

(Or palladium-phosphorus alloy) coating film on the nickel-phosphorus / gold plating layer or the nickel-phosphorus / palladium (or palladium-phosphorus alloy) / gold plating layer formed on the copper layer in comparison with the thickness of the nickel- In order to cope with the deformation of the flexible printed circuit board, it is necessary to improve the bendability (resistance to deformation such as bending) of the nickel-phosphorus film because the thickness is relatively much thinner.

Accordingly, a method of improving the bending resistance of the nickel-phosphorus film is sought.

Embodiments of the present invention provide an electroless nickel plating solution with improved bending resistance and an electronic part with improved bending resistance by forming a plating layer using the electroless nickel plating solution.

According to an aspect of the present invention, there is provided an electroless nickel-phosphorus plating solution comprising a water-soluble nickel salt, a reducing agent, a stabilizer, a complexing agent, and a pH adjusting agent. In order to improve the bending resistance of the electroless nickel- An electroless nickel plating solution may further be provided.

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According to another aspect of the present invention there is provided a pharmaceutical composition comprising 10 to 45 g / L nickel sulfate hexahydrate, 15 to 45 g / L sodium hypophosphite monohydrate, 1 to 40 ml / L of 28% ammonia water, 1 to 20 g / 1 to 20 g / L of adipic acid, 1 to 20 g / L of adipic acid, 1 to 10 g / L of sodium glutamate monohydrate, 0.1 to 50 mg / L of lead acetate trihydrate, 0.05 to 5 mg / An electroless nickel plating solution containing 0.0001 to 1 mg / L of pentaamine can be provided.

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According to still another aspect of the present invention, there is provided an electronic component in which a plating layer is formed using the electroless nickel plating solution, wherein the electronic component may be a flexible printed circuit board.

Embodiments of the present invention can improve the bending resistance of the electroless nickel plating solution by adding a specific compound to the plating solution to cause the nickel (or nickel-phosphorus) coating to grow in the vertical direction of the copper layer.

Further, by forming the plating layer using the electroless nickel plating solution, the bending resistance of an electronic component such as a flexible printed circuit board can be improved.

1 is an image of a plating layer formation in a conventional electroless nickel plating solution.
2 is an image of a plating layer formation in an electroless nickel plating solution according to an embodiment of the present invention.

Hereinafter, embodiments of the present invention will be described in detail.

The electroless nickel plating solution according to an embodiment of the present invention is characterized by further comprising a water-soluble nickel salt, a reducing agent, a stabilizer, a complexing agent and a pH adjusting agent, .

[Chemical Formula 1]

_{R1 - [(CH 2) l} -NH- (CH 2) m] n -R2

Here, l, m, n are R1 and R2, in the case where an integer of 1 or more, n = 1 is NH _2. In addition, n it is 2 or more in the case R1 and R2 may be NH _2, CH _3, that is selected from OH, CH ₂ OH, COOH R1 and R2 are the same or different.

In the present specification, the term "electroless plating solution" means a plating solution used for electroless plating. In the electroless plating, the metal ions contained in the plating solution are electroplated through a chemical reaction without using electricity. It uses the principle that it receives electrons and sticks to the surface of the object to be reduced and plated.

Hereinafter, each configuration will be described.

(1) The water-soluble nickel salt is a main material to be precipitated and plated. Examples of the water soluble nickel salt include nickel sulfate, nickel chloride, nickel acetate, nickel carbonate, nickel hydroxide, and mixtures thereof, but not limited thereto, and may include all known water soluble nickel salts. The content of nickel ion in the water soluble nickel salt may be 0.5 to 20 g / L. If the content of the water-soluble nickel salt (or nickel ion) is excessively large, there is a problem that the cost of production of the product is increased more than necessary. On the other hand, when the content is too small, plating is not performed.

(2) The reducing agent functions to reduce nickel ions to nickel metal. The reducing agent may include hypophosphorous acid or hypophosphite, but is not limited thereto, and may include all known reducing agents used in the electroless nickel (or nickel-phosphorus) alloy plating solution. On the other hand, examples of the hypophosphorous acid and hypophosphite include sodium hypophosphite, potassium hypophosphite, and the like. The content of the reducing agent may be 0.1 to 100 g / L. When the content of the reducing agent is excessively large, the production cost of the product is increased more than necessary and the stability of the plating solution is deteriorated. On the other hand, when the amount is too small, plating is not performed.

(3) The stabilizer has a function of inhibiting the decomposition of the plating liquid, and may serve as a grain refinement agent for reducing nickel particles to be precipitated. When the crystal grains of the nickel particles are made finer, the weldability and the bending resistance can be improved. The stabilizer may be a compound containing a heavy metal such as lead, bismuth, or a compound containing sulfur. Examples of the former include, but are not limited to, lead acetate, lead citrate, bismuth acetate, and bismuth citrate. Examples of the latter include thiourea, alkylthiourea, thiodiacetate, thiodiacetate, thiodiglycolate, dithionate, dithionate salt, thiosulfate, thiosulfate, sodium thiosulfate, sodium thiocyanate , Potassium thiocyanate, thioglycolic acid, and the like, but are not limited thereto. The content of the stabilizer may be 0.0001 to 100 mg / L. If the content of the stabilizer is excessively large, there is a problem that plating can not be performed. Conversely, if the amount is too small, the stability of the plating solution is deteriorated.

(4) The complexing agent functions to ignite a nickel salt to supply stable nickel ions. The complexing agent may be a carboxylic acid such as succinic acid, adipic acid, lactic acid, malonic acid, citric acid or oxalic acid, or a salt thereof, or an amino acid such as glycine, glutamic acid, glutamate, But the present invention is not limited thereto and may include all known complexing agents used in the electroless nickel-phosphorus alloy plating solution. The content of the complexing agent may be 0.1 to 100 g / L. If the content of the complexing agent is too large, there is a problem that the production cost of the product increases more than necessary. On the contrary, when the amount is too low, the stability of the plating solution is lowered or the deposition rate is lowered.

(5) The pH adjusting agent functions to adjust the pH of the plating solution. The pH adjusting agent may include an acid or a base. For example, the pH adjusting agent may include an acidic substance such as sulfuric acid, phosphoric acid, hydrochloric acid, sulfuric acid, nitric acid, or carbonic acid, or an alkylic substance such as ammonia water, sodium hydroxide, potassium hydroxide, And the like. In addition, the pH adjuster is not limited to the above listed materials, and may include all known materials including acids and / or bases for adjusting the pH of the plating solution. The pH adjusting agent is added in order to achieve the desired pH of the plating liquid, so that it may have various contents depending on the case.

(6) The compound represented by the formula (1) functions to improve the folding endurance of the electroless nickel plating solution according to one embodiment of the present invention. The above formula (1) may include diethylene triamine, triethylene tetramine, or tetraethylene pentaamine, but not limited thereto, and may include all compounds satisfying the above formula (1). In the present specification, the term " bending resistance "refers to a property of bending or the like to resist deformation. The term " improved bending resistance " means that the degree of bending or breaking is lowered.

FIG. 1 is an image of a plating layer formation in a conventional electroless nickel plating solution, and FIG. 2 is an image of a plating layer formation in an electroless nickel plating solution according to an embodiment of the present invention. 1 and 2 were photographed at a magnification of × 10,000 using a scanning electron microscope (SEM).

Referring to FIGS. 1 and 2, in the conventional electroless nickel plating solution, since the copper layer tends to grow in the horizontal direction during the growth of the nickel coating, there is a problem that the bending resistance can not reach the desired level (FIG. However, in the electroless nickel plating solution according to one embodiment of the present invention, the polyamide was added so that the nickel film was first grown in the vertical direction of the copper layer to improve the bending resistance (FIG. 2). This will be supplemented by a test example to be described later.

The content of [Formula 1] may be 0.00001 to 100 mg / L. When the content of [Formula 1] is excessively high, the plating rate is lowered. On the other hand, when the content is too small, vertical growth of the nickel plating layer is not achieved properly.

As described above, the embodiments of the present invention have an advantage in that the nickel film including the polyamine grows in the vertical direction of the copper layer, thereby improving the bending resistance of the electroless nickel plating solution.

Further, in the present invention, it is possible to further provide an electronic component in which a plating layer is formed using the electroless nickel plating solution described above. At this time, the electronic component may be a flexible printed circuit board. Since the plating layer is formed by the electroless nickel-phosphorus alloy plating solution having improved bending resistance, the electronic component (flexible printed circuit board) has an advantage that the life of the product is prolonged because it is not damaged / destroyed even when used for a long time.

Hereinafter, a test example of the present invention will be described. However, it is apparent that the following test examples do not limit the present invention.

Test Example

(One) Comparative Example  And Example  Ready

For the test, the plating solutions of Comparative Examples described in [Table 1] and Examples 1, 2, and 3 were prepared. Further, a flexible printed circuit board on which a copper (wiring) layer was formed through a pretreatment process for plating such as degreasing, acid cleaning, and surface activation treatment was prepared.

Next, 5 liters of ion-exchanged water was filled in a 10-liter vessel, and a plating bath of Comparative Example and Examples 1, 2 and 3 were respectively added and dissolved. Then, ion-exchanged water was used to make a total volume of 10 liters, (PH was adjusted to 4.6). Next, the flexible printed circuit board was immersed in the plating bath at 82 캜 for 10 minutes to obtain a flexible printed circuit board on which a nickel-phosphorus plating layer was formed. Next, the flexible printed circuit board was immersed in a gold plating solution (AUL-5, KPM TECH) to form a gold-plated layer having a thickness of 0.04 to 0.08 μm on the nickel-phosphorous plating layer.

 (2) Bending  evaluation

The comparative example prepared in the above (1) and the examples 1, 2, and 3 were subjected to an endurance evaluation test. The above-mentioned bending resistance evaluation test was carried out through the evaluation method prescribed in JIS P 8115 (method of evaluating the bending resistance of a tributary and a plate tributary). More specifically, the flexible printed circuit boards corresponding to the comparative example and the first, second, and third embodiments were attached to the JIS P 8115 MIT automatic bending test machine, and the bending times until the flexible printed circuit board was broken were measured.

(3) Test results

In Table 1 below, the compositions of Comparative Examples and Examples 1, 2 and 3, the content of each composition, the thickness of the plating layer and the evaluation results of the bending resistance are summarized. Comparative Example and Examples 1, 2, and 3 were obtained by dipping the flexible printed circuit board in the plating bath at 82 캜 for 10 minutes as described above to form a plating layer (pH is 4.6).

unit Comparative Example Example 1 Example 2 Example 3 Nickel sulfate hexahydrate g / L 22 22 22 22 Sodium hypophosphite monohydrate g / L 25 25 25 25 28% ammonia water ml / L 30 30 30 30 Lactic acid g / L 15 15 15 15 Malic acid g / L 10 10 10 10 Adipic acid g / L 10 10 10 10 Sodium glutamate monohydrate g / L 5.0 5.0 5.0 5.0 Lead acetate trihydrate mg / L 1.0 1.0 1.0 1.0 Thiourea mg / L 0.1 0.1 0.1 0.1 Diethylenetriamine mg / L - 0.01 - - Triethylenetetraamine mg / L - - 0.005 - Tetraethylene pentaamine mg / L - - - 0.003 Plating layer thickness (10 minutes) 2.0 1.9 1.9 1.8 Bending resistance (bending frequency) Number of times 78 313 415 435

Referring to Table 1, the electroless nickel-phosphorus alloy plating solution (Examples 1, 2 and 3) containing diethylenetriamine, triethylenetetraamine or tetraethylenepentamine under the same conditions as those of the electroless nickel- (4 times or more) in comparison with the case where the case is not the case (Comparative Example).

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, many modifications and changes may be made by those skilled in the art without departing from the spirit and scope of the invention as defined in the appended claims. The present invention can be variously modified and changed by those skilled in the art, and it is also within the scope of the present invention.

Claims (5)

An electroless nickel plating solution comprising a water-soluble nickel salt, a reducing agent, a stabilizer, a complexing agent, and a pH adjuster, wherein the electroless nickel plating solution further comprises tetraethylene pentaamine for improving resistance to bending of the electroless nickel plating solution. Nickel sulfate hexahydrate 10 to 45 g / L, sodium hypophosphite monohydrate 15 to 45 g / L, 28% ammonia water 1 to 40 ml / L, lactic acid 1 to 20 g / 1 to 20 g / L of dibasic acid, 1 to 10 g / L of sodium glutamate monohydrate, 0.1 to 50 mg / L of lead acetate trihydrate, 0.05 to 5 mg / L of thiourea and 0.0001 to 1 mg / And an electroless nickel plating solution. delete An electronic component in which a plating layer is formed using the electroless nickel plating solution according to claim 1 or 2. The method of claim 4,
Wherein the electronic component is a flexible printed circuit board.

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