KR20090010406A - Tin-nanodiamond composite electroplating solution and plating method using the same - Google Patents

Abstract

A tin-nanodiamond composite electroplating solution and an electroplating method using the same are provided to completely prevent or considerably reduce the generation of whisker even if tin plating is performed through electrolysis by dispersing nanodiamonds into a tin plating electrolyte. A tin-nanodiamond composite electroplating solution includes a tin plating electrolyte comprising a tin ion supply compound and one or more organic acids or basic compounds, and nanodiamonds dispersed into the tin plating electrolyte. The organic acids are selected from the group consisting of sulfonic acid, sulfuric acid and sulfamic acid, hydrochloric acid, citric acid, lead hydrofluoric acid, succinic acid, malic acid, acetic acid, phenol sulfonic acid, alkyl sulfonic acid, and alkanol sulfonic acid. The basic compounds are selected fromin the group consisting of carbonate salts, hydroxide salts, and cyanide salts. The nanodiamonds are nanodiamond particles, detonation nanodiamonds, or mixed nanodiamonds of the nanodiamond particles and denotation nanodiamonds.

Description

Tin-nanodiamond composite plating solution and electroplating method using the same {Tin-nanodiamond Composite Electroplating Solution and Plating Method using the same}

The present invention relates to a tin-nanodiamond composite plating solution and a tin-nanodiamond composite plating method using the same, and more particularly, nanodiamonds are dispersed in a tin-plated electrolyte to reduce the occurrence of whiskers in the plating film, and the corrosion resistance of the plating film. And a tin-nanodiamond composite plating solution capable of improving wettability and a tin-nanodiamond composite plating method using the same.

Electrolytic tinplate coated with lead used to date has good wettability, increased corrosion resistance and no whisker formation, but many countries forbid or restrict the use of lead due to environmental problems. Therefore, in order to solve such environmental problems, research on pure tin plating without using lead has been actively conducted in the electronic component industry.

As a conventional tin plating method, various methods such as deposition in molten tin, an electroplating method, and an electroless plating method are used. The method of immersion in molten tin is not well used due to the high consumption of tin, uneven plating surface, and high process temperature for the substrate.

Electroless tin plating is widely used due to its low price, simplicity of process, and satisfactory quality, but it is not only stable in management, but also often has a disadvantage of not having a plating thickness of 1 μm or more. There is a short disadvantage. Moreover, drawbacks have arisen in that sufficient technical means for reliable replenishment and regeneration of electrolytes used in electroless plating processes have not been secured.

Electrolytic tin plating method is preferred because it has the advantage of being able to manufacture and control the surface of the plating in various ways, whisker growth due to the stress of the tin plating film is a problem. Such whiskers on the plated film cause short circuits of electrical and electronic components after plating, and therefore it is necessary to minimize the occurrence of whiskers.

In order to suppress the formation of whiskers in electrolytic tin plating, a method of alloy plating with platinum group elements such as bismuth, lead, cobalt, nickel, gold, silver, zinc, indium, and palladium is known. However, this method has a problem that the whisker prevention effect is insufficient, and the wettability of the plated film is deteriorated or has a high fracture characteristic.

The quality of the plated film obtained by electroplating is generally dependent on the composition of the electrolyte, the size and nature of the dispersed particles, and the stability to precipitation and aggregation of the particles. British Patent No. 1391001 discloses tin chloride 30-50 g / L, nickel chloride 240-320 g / L, ammonium fluoride 60 g / L, and ammonium hydroxide 2.0-2.5. Disclosed is a technique in which diamond particles having a particle size of 0.01 to 30.0 mm are mixed and plated with an electrolyte containing g / L at a concentration of 1 to 20 g / L.

However, this method consumes too much expensive diamond and is pretreated with hydrochloric acid, sodium carbonate, cowmarin sulfate and sulfuric acid and washed with water at least once to ensure that the diamond particles are safe for precipitation in the electrolyte. Additional processes such as surface activation are required, and the process is complicated, such as stirring the electrolyte at a constant rate during the plating process, and uniformity of the plating, such as the generation of pores in the finally obtained plating film. This bad and cavitation phenomenon appears.

SUMMARY OF THE INVENTION The present invention is directed to overcoming the above-mentioned problems of the prior art, and one object of the present invention is to completely prevent or considerably generate whiskers by pure tin plating while maintaining good wettability on the tin plated film by using a small amount of nanodiamonds. It is to provide a tin-nanodiamond composite plating solution that can be reduced.

Another object of the present invention is to provide a tin-nanodiamond composite plating method using the tin-nanodiamond composite plating solution.

Still another object of the present invention is to provide a plating film formed by using the tin-nanodiamond composite plating solution and a plating material including the same.

One aspect of the present invention for achieving the above object is

A tin-nanodiamond composite plating solution comprising a tin plated electrolyte comprising a tin ion supply compound, at least one organic acid or a basic compound, and nanodiamonds dispersed in the tin plated electrolyte.

Another aspect of the present invention includes the steps of preparing a tin-nanodiamond composite plating solution according to the present invention and placing a tin anode plate and a cathode plate in the composite plating solution and applying a current to the tin cathode plate and the cathode plate to perform electroplating A tin-nanodiamond composite plating method characterized by the above-mentioned.

Another aspect of the present invention relates to a plating film formed by using the tin-nanodiamond composite plating solution of the present invention and a plating material including the same.

Hereinafter, the present invention will be described in more detail.

The tin-nanodiamond composite plating solution of the present invention is characterized in that it comprises a tin plating electrolyte comprising a tin ion supply compound and at least one organic acid or basic compound, and nanodiamonds dispersed in the tin plating electrolyte.

In the present invention, as the tin plating electrolyte, both an acidic electrolyte or an alkaline electrolyte may be used. In the case of an acidic electrolyte, one or more organic acids may be used. The type of organic acids usable in the present invention is not particularly limited, but examples thereof include sulfonic acid, sulfuric acid, sulfamic acid, hydrochloric acid, citric acid, boric acid, succinic acid, malic acid, acetic acid, and phenolsulfonic acid. , Alkylsulfonic acids, alkanolsulfonic acids, and the like. In the present invention, the composition ratio of each component constituting such a tin plating electrolyte is not particularly limited, and may be composed of the same composition as a conventional tin plating electrolyte. The hydrogen ion concentration of the acidic electrolyte is preferably in the range of about pH 1 to pH 6.

On the other hand, in the case of an alkaline electrolyte, at least one basic compound is included. Although the kind of such a basic compound is not specifically limited, A carbonate salt, a hydroxide salt, a cyanide salt, etc. can be used.

The tin ion supply compound in the tin-nanodiamond composite plating solution of the present invention may be selected from the group consisting of eutectic tin-based, organic sulfate-based tin, organic sulfamic acid-based tin, boride tin, tin chloride, tin oxide, and the like. However, it is not necessarily limited thereto.

In the present invention, the nanodiamond is a conventional nanodiamond particle (ND), or a nanodiamond (Detonation Nanodiamond: "DND") by the explosive synthesis method or a mixture of the conventional nanodiamond (ND) and nanodiamond (DND) by the explosion synthesis method. It may be a mixed nanodiamond. The traditional nanodiamonds (ND) include natural nanodiamonds, general synthetic nanodiamonds or static pressure synthetic nanodiamonds. In the case of the mixed nanodiamond, the mixing ratio of nanodiamond (ND) and DND is 99: 1 to 50:50.

Since nanodiamonds have a high adsorption force due to high surface energy, they act as powerful fillers during metal plating, adsorbing ionized tin to reduce the formation of intermetallic compounds (Cu _x Sn _y ) between the substrate and the plating layer. Can be. In other words, ND particles enter the plating layer during metal plating, in contrast to other additives, which are active fillers, and have an unusual effect on the structure and properties of the plating layer, thus reducing the compressive stress applied to the tin plating layer to prevent the occurrence of whiskers. Can be significantly reduced.

The size of the nanodiamonds (ND) usable in the present invention is not particularly limited, but the particle size of the nanodiamond particles may be in the range of 1 to 500 nm, and the particle size of the nanodiamonds may be in the range of 1 to 10 nm.

The explosive synthetic nanodiamonds (DND) usable in the present invention differ greatly in structure and properties from traditional nanodiamonds. DND is produced through a powerful explosion reaction using oxygen, which is negatively charged to gases, water and ice, which are not oxidizing agents. For example, the manufacturing method of DND is a mixture of trosil and hexogen in a 50:50 ratio, the explosion pressure is 22 ~ 28 GPa and the temperature reaches 3000 ~ 4000K. After chemical purification, after purification in nitric acid solution at a temperature of 220 ~ 240 degrees Celsius and pressure of 100 atm and then separated into a pure form, a dispersion aqueous solution of DND is usually obtained [Russian Federal Patent N 2109683, " The method of isolation of synthetic ultradispersed diamonds "V.Yu.Dolmatov, VG Suschev and others, BI N 12, 1998].

Nanodiamonds by explosive synthesis have the following characteristics:

1. Purified solid DND exists in irregular particle form and consists of spherical aggregated carbon and diamond.

2. The central carbon atom has the cubic crystal structure (sp ³ -hybridization) of a typical diamond, and the center contains 70 to 90% of carbon atoms. Is in range. The closest inner shell of the DND nucleus is a continuous layer of onion-like structure, a structure called six-atomic sp ² bonds, or hexahedrons, inferred that a disconnected graphite monolayer is located within the same shell. . Amorphous carbon shells are porous, have a discontinuous carbon structure with numerous defects, and the surface is modified by various functional groups during explosive synthesis. Representative functional groups include, but are not necessarily limited to, functional groups containing oxygen such as hydroxyl groups, carboxyl groups, ketone groups, lactone groups and the like.

In other words, considering that the majority of the center and surrounding shells are composed of carbon, most of the heteroatoms constituting the functional group are present in the surface layer, and half of their contents are exposed on the surface. In other words, DND particles are not pure carbon materials but are carbon modified simultaneously, with only one of them having a diamond structure. Quantitative variables that determine the composition and size of the layers can be varied depending on the synthesis conditions and subsequent separation methods.

In addition, the electrophoretic charge size of the nanodiamond (DND) surface by the explosive synthesis method is about 10 times the electrophoretic charge size of the conventional nanodiamond surface, the specific surface area of the DND is the size of the specific surface area of the nanodiamond It is about 30 times.

Addition of nanodiamond (DND) by explosive synthesis into the tin-plated electrolyte causes the adsorption (1 ~ 10 ㎍-equiv / m ² ) to fix the acid or absorb the residues of metal bases, Increase to facilitate the formation of microcrystals in the plating. Due to this fact, in the role of nanodiamond particles it is there.Aye to adsorb metal hundreds of milligrams in about several tens of the metal components, including Cr ⁶⁺ in the NCD (DND) 1g by explosion synthesis Metal ions move to the cathode Contribute.

Since nanodiamond particles adsorb or react from tens to hundreds of milligrams of ionized tin per gram of DND, they are involved in the transport of metal ions on the surface of the substrate (e.g., copper foil). The formation of intermetallic compounds (CuSn _x ) between the two layers by interdiffusion of the layers can be drastically reduced, and the compressive stress applied to the tin-plated layer can be reduced to completely eliminate or significantly reduce the occurrence of whiskers.

In the tin-nanodiamond composite plating solution of the present invention, the nanodiamond may be dispersed in the tin-plating electrolyte at a concentration of 0.01 to 99 g / L, and more preferably in a concentration range of 0.1 to 10 g / L. When the nanodiamond concentration is less than 0.01 g / L, the tin layer is not adsorbed or the effect of the ionic reaction is insufficient to suppress or reduce the whisker generation to the extent that the short circuit can be prevented. When the nanodiamond concentration exceeds 99 g / L, the nanodiamond Precipitation may cause a problem in the quality of the plating layer.

The tin-nanodiamond composite plating solution of the present invention may be added with other additives such as dispersants, stabilizers, surfactants to improve the physical properties of the plating film. Such additives are not particularly limited as long as they do not impair the physical properties of the tin-nanodiamond plating film. For example, ammonium sulfate, polyethylene glycol, polyethylene oxide, ascorbic acid, catechol, glutamic acid, hydroquinone, benzophenone, and fatigue. Catechol, benzaldehyde, hydroxyamine, hypophosphite, hydrazine and the like can be used.

In the present invention, the tin plating electrolyte includes methyl sulfonic acid electrolyte including methyl sulfonic acid, ammonium sulfate, polyethylene glycol and methane sulfonic acid tin, tin sulfate, sulfuric acid electrolyte and sulfamic acid including sulfuric acid and polyethylene oxide (eg, OC-20), It may be one selected from the group consisting of sulfamic acid electrolytes including tin sulfate, ascorbic acid, polyethylene glycol and polyethylene oxide, but is not necessarily limited thereto.

Tin-nanodiamond composite plating solution according to the present invention may further include one or more selected from the group consisting of bismuth, gold, silver, indium, palladium, ruthenium, rhodium, pentium, iridium and platinum, but must be It is not limited to these. The elements of such bismuth, gold, silver and platinum groups may be included in an amount of 0.5 to 50% by weight based on the total weight of the composite plating solution.

Another aspect of the present invention relates to a tin-nanodiamond composite plating method using the tin-nanodiamond composite plating solution of the present invention. In the case of tin plating by the method of the present invention, after first preparing a tin-nanodiamond composite plating solution, a tin anode plate and a cathode plate are disposed in the prepared composite plating solution, and electroplating is performed by applying a current between the tin anode plate and the cathode plate. do.

The composition of the tin-nanodiamond composite plating solution used in the method of the present invention is prepared with the same components and composition ratios as described above. In the present invention, a method of preparing such a tin-nanodiamond composite plating solution is not particularly limited. For example, after preparing a tin plating electrolyte including a tin ion supply compound and at least one organic acid or a basic compound, nanodiamond is added to the tin plating electrolyte. And distilled water may be prepared to disperse the nanodiamonds at a concentration of 0.001 to 99 g / L.

When the tin-nanodiamond composite plating solution is prepared, the tin positive electrode plate and the negative electrode plate are installed in the composite plating solution and subjected to electroplating. At this time, the current density of the current applied to the tin positive electrode plate and the negative electrode plate is preferably 0.05 ~ 20A / dm 2.

Another aspect of the present invention relates to a plating film formed by using the tin-nanodiamond composite plating solution of the present invention and a plating material having such a plating film. The tin-nanodiamond plating film can significantly reduce whisker generation or no whisker generation compared to conventional plating films, thereby preventing short circuits of electrical and electronic devices, reducing corrosion resistance, and improving wettability. It can be applied to the preparation of.

Hereinafter, a preferred embodiment of the present invention will be described in detail with reference to examples, but these examples are for illustrative purposes only and are not intended to limit the protection scope of the present invention.

Example

Example 1

180 ml of methanesulfonic acid (r = 1.36 g / cm ³ ) is added to 300 ml of distilled water at room temperature and then stirred well (solution 1). Separately, 130 g of ammonium sulfate and 10 g of polyethylene glycol are dissolved in 350 ml of water and stirred well while heating (solution 2). Separately, 5 g of polyethylene oxide is dissolved in 30 ml of distilled water and stirred well while heating (solution 3). Solutions 1, 2, and 3 were mixed to prepare a methanesulfonic acid electrolyte. Then, 5 g of 10 wt% of nanodiamond dispersion was added thereto, distilled water was filled in the obtained electrolyte, adjusted to 1 L, and stirred to use a tin-sulfonic acid electrolyte. Prepare a nanodiamond composite plating solution.

The tin-nanodiamond composite plating solution obtained above was filled in a 0.5 L electrolyzer, and a tin plate was used as the anode plate, and a plate of copper alloy was placed as the cathode plate, and electroplating was performed by applying a current between the anode plate and the cathode plate. .

The current efficiency in the methanesulfonic acid tin electrolyte was 90-100% at 1.2 ~ 2.22 A / dm ² . It took 18 minutes at current density i _k = 1.2 A / dm ² and 10 minutes at i _k = 2.2 A / dm ² to obtain a plating thickness of 10 mm.

[Composition of tin-nanodiamond plating solution]

Methanesulfonic acid (r = 1.36 g / cm ³ ) 180 ml / L

Ammonium Sulfate 130 g / L

Polyethylene glycol (OC-20) 10 g / L

Methanesulfonic acid tin 130 g / L

Polyethylene oxide 5 g / L,

Nanodiamond 0.2 g / L

[Tin-nanodiamond plating condition]

Current density ( i _k ) 1.2 A / dm ²

Temperature 20 ~ 22 ^O C

As shown in Table 1, the content of the nanodiamonds was differently plated, and the physical properties of the plated plating films were evaluated, and the results are shown in Table 1 together.

[Plating film property evaluation method]

The physical properties of the specimen plated in the present invention was evaluated by the following method.

Wettability of plating

Wetting of the plating was measured by the spreading method of the solder specimen. This method is based on the ability of solder to spread at predetermined temperature and flux composition conditions on the plating surface. The solder is preliminarily cut into disks with a thickness of 0.3 mm and a predetermined diameter. The solder and samples are washed with alcohol, and the intermediate dirty samples are washed in turn to proceed as follows: first drop a drop of flux, drop a drop of solder and repeat one more time.

 The solder is raised 265 ± 5 ° C relative to the melting point of the solder and heated for 3 seconds. Then cool to room temperature. Alcohol, resin and solder POS-61 (tin-lead alloy, 61 wt.% Sn) were used to control the solder properties.

After measuring the spread area of the solder, the solder spreadability (wetting coefficient) was calculated. Solder spreadability can be assessed by the spreadability for plating: higher spreadability indicates better spreadability. Samples obtained immediately after plating and samples left for 1 month after plating and all samples left at low temperature, below 10 ° C. for 1 month after plating were tested.

Fine hardness

Microhardness was evaluated using the microhardness tester PMT-3 (Russia). The load time of the load was 10 to 15 seconds with 10g of 1N of diamond pyramid probe load. The measurement was carried out according to the Russian standard standard GOST 9.450-76.

Weight loss due to wet etching (current efficiency)

Current efficiency was measured by gravimetric method. Plating thickness was measured by the increase of the sample. Evaluation of stability was evaluated with pickling solution. The experimental method is as follows:

Copper was added to NH ₄ OH to CuCl ₂ 80 g / L and NH ₄ Cl 100 g / L to keep the pH to 8.7 and the temperature is in 45 ℃ and the etching time is the time required for queue Pro ammonium activity of the pickling solution It carried out for 2 minutes and measured the weight before and after an etching. The less weight loss, the more firmly plated tin on copper.

Measure for whisker generation

The samples are placed in a dryer at room temperature and the other samples are placed in a freezer at -10 ° C. After being left at room temperature for about 20 degrees for one month, samples were magnified at a magnification of 100 times with an electron microscope to observe whether whiskers were formed.

Example  2 -6

The plating was carried out in the same manner as in Example 1 except that the content of nanodiamonds was changed as shown in Table 1 below, and the physical properties of the plated coating films were evaluated, and the results are shown in Table 1 below. .

Comparative Example 1

Except that the nanodiamond was not added to the tin plating solution was carried out in the same manner as in Example 1 and subjected to tin plating and the results are shown in Table 1 below.

Yes ND / DND (g / L) Current density (A / dm ^{2 )} Uniform Electrodeposition (cm) Microhardness (kg /?) Weight loss due to wet etching (g) Wettability Create Whiskers Comparative Example 1 0/0 1.2 - 13.3 0.0012 1.4 much 2.2 1.09 12.5 0.0014 2.1 much Example 1 0.2.0 1.2 - 12.0 0.0006 1.8 none 2.2 1.02 13.0 0.0004 1.7 none Example 2 1.0 / 0 1.2 - 12.8 0.0004 1.75 none 2.2 0.9 - none Example 3 0 / 0.2 1.2 - 13.2 0.0008 1.9 handful 2.2 1.1 12.5 0.0005 1.9 handful Example 4 0 / 1.0 1.2 - 12.2 0.0006 1.94 handful 2.2 1.0 13.1 0.0003 2.16 handful Example 5 0.2 / 0.2 1.2 - 12.6 0.0002 2.4 none 2.2 1.0 12.5 0.0002 2.4 none Example 6 1.0 / 1.0 1.2 - 12.6 0.0001 2.6 none 2.2 1.0 13.2 0.0001 3.0 none

With the addition of nanodiamonds, the stability of tin plating in the pickling solution was improved due to increased corrosion resistance as a result of reduced pores in the plating. 6-30% increase. The wettability of the solder on samples left for one month increased by 1.5-2.5 times due to the large decrease in grain size of the plating.

When mixed nanodiamond is present in the electrolyte, the wettability coefficient (solder ability) is greatly increased in both the plated sample and the plated sample left for one month. On average, wetting coefficient increased 1.5-2.0 times.

Example 7

Add 57.8 ml (100 g) of 94% sulfuric acid to 200 ml of distilled water with agitation. Separately, add tin sulfate (60g ) to 250ml distilled water to dissolve it by heating, stir the solution well, and put it in the prepared sulfuric acid solution. The prepared electrolyte is thoroughly filtered through a double filter paper. To prevent the transition of Sn ⁺² to Sn ⁺⁴ , some tin flakes are placed at the bottom of the flask to remove tin tetravalent sludge during filtration. 5 g of polyethylene oxide is dissolved in 50 ml of distilled water while heating. The obtained solution was cooled and added to the electrolyte containing filtered sulfuric acid and tin sulfate to prepare a tin sulfate electrolyte. Finally, 20 ml of mixed 0.5 g of ND and 0.5 g of DND (1 g of total) are added to the prepared electrolyte while stirring well. Then, distilled water was filled into the electrolyte to make 1 L and thoroughly stirred to prepare a tin-nanodiamond composite plating solution using a tin sulfate electrolyte. The specimen was plated through a plating process similar to Example 1.

The current efficiency of tin in the tin sulfate electrolyte was 90-100% in the current density range 0.5-2.0 A / dm ² . In the plating time, the time it takes to achieve a plating thickness of 10 mm is the current density i _k = 1.0 A / 19.8 min _{^{dm 2, i k = 2.0 A}} / dm 2 was 10 minutes at.

Plating Solution Composition Using Tin Sulfate Electrolyte

Tin Sulfate 60 g / L

Sulfuric acid (r = 1.84 g / cm ³ ) 100 g / L

Polyethylene Oxide (OC-20) 5 g / L

ND + DND (50/50) 0.5 + 0.5 g / L

[Plating Conditions Using Tin Sulfate Electrolyte]

Current density ( i _k ) 1.0 A / dm ²

Temperature ℃ 18 ~ 20

The physical properties of the plated film plated under the above conditions were evaluated and the results are shown in Table 2 below.

Example 8-10

The plating was carried out in the same manner as in Example 7, except that the content of the nanodiamonds was changed as shown in Table 2 below. .

Comparative Example 2-3

Except not having added the nanodiamond in the tin plating solution, except that the composition of the electrolyte was carried out in the same manner as in Example 7, except that the tin plating was carried out and the results are shown in Table 2 below.

Electrolyte composition Current density (A / dm ²⁾ Uniform Electrodeposition (cm) Fine hardness (g / mm ² ) Weight loss due to wet etching (g) Wettability Create Whiskers Comparative Example 2 Tin sulfate 40 g / L Sulfuric acid 80 g / L OC-20 5 g / L i _k = 0.5  1.10  7.5  15  1.6 Slightly Comparative Example 3 Tin sulfate 60 g / L Sulfuric acid 100 g / L OC-20 5 g / L i _k = 1,0 1,05 7,3 18 1,7 Slightly Example 7 Comparative Example 2 + CND 0.5 g / L i _k = 1.0 1.16 7.8 9 2.0 none Example 8 Comparative Example 2 + CND 2.0 g / L i _k = 1.5 1.21 8.7 7 2.1 none Example 9 Comparative Example 2 + + CND + DND (1.0 / 1.0 g / L) i _k = 2.0 1.24 8.2 2 2.1 none Example 10 Comparative Example 2 + CND (1.0 g / L) i _k = 2.0 1.17 8.2 4 2.0 Slightly

The wettability coefficients of samples obtained from tin sulfate electrolyte increased 1.5 times as in methanesulfonic acid electrolyte and increased 2.5 times in plating after 1 month of standing. Both nanodiamonds, nanodiamonds and nanodiamonds by explosion have a positive effect on the properties of tin plating, and have been found to greatly reduce the pores of plating, reduce corrosion resistance and improve wettability.

Example 11

Add 60 g of sulfamic acid to 300 ml of distilled water and stir while heating to dissolve. Separately, 40 g of tin sulfate was added to 200 ml of distilled water, followed by stirring well. The resulting solution was added to sulfamic acid and cooled to room temperature. The resulting solution was thoroughly filtered through a double filter paper using a 1.5 L flask. 10 g of polyethylene oxide (OC-20) was added to 100 ml of hot distilled water, dissolved, cooled to room temperature, and the filtered sulfamic acid and tin sulfate solution were put together in a 1.5 L flask. 1 g of ascorbic acid and 4 g of polyethylene glycol are separated, dissolved in distilled water, and then the solution is sequentially added to a 1.5 L flask to prepare a sulfamic acid electrolyte. Finally, 10 ml of 10% ND aqueous solution was added thereto to prepare a tin-nanodiamond composite plating solution using a sulfamic acid electrolyte. The plating process was carried out similarly to Example 1.

The current efficiency of tin in the sulfamic acid tin electrolyte was in the range of 90-100%. Plating time of 10 mm plating time was 40 minutes at current density i _k = 0.5 A / dm ² and 13,2 minutes at i _k = 1.5 A / dm ² .

Plating Solution Composition Using Sulfamic Acid Tin Electrolyte

Sulfamic Acid 60 g / L

Tin Sulfate 40 g / L

Ascorbic acid 1.0 g / L

Polyethylene glycol 4 g / L

Polyethylene oxide 10 g / L

Nanodiamond (ND) 1.0 g / L

[Plating Conditions Using Sulfamic Acid Tin Electrolyte]

Current density ( i _k ) 1.5 A / dm ²

Temperature 18-25 ^O C

The results of tin plating obtained in Example 11 are shown in Table 3.

Example  12 -14

Except for the content of nanodiamonds as shown in Table 3, except that the same as in Example 11 to perform a tin-nanodiamond composite plating, the physical properties of the plated coating film was evaluated and the results are shown in the following table 3 is shown together.

Comparative Example 4

Except that the nanodiamond was not added to the tin plating solution was carried out in the same manner as in Example 3 and subjected to tin plating and the results are shown in Table 3 below.

Electrolyte composition Current density (A / dm ^{2 )} Uniform Electrodeposition (cm) Microhardness (kg / mm ² ) Weight loss by wet etching (g) Wettability Create Whiskers Comparative Example 4 Sulfamic acid 60 g / L Tin sulfate 40 g / L Ascorbic acid 1.0 g / L Ethylene glycol 4 g / L OC-20 10 g / L i _k = 0.5  -  11.2  0.0009  1.6 Average quantity i _k = 1.5 2.02 11.5 0.0015 2.0 Average quantity Example 11 Comparative Example 4 + CND (0.1 g / L) i _k = 0.5 - - 0,0001 3.0 none i _k = 1.5 2.95 11.0 0 2.7 none Example 12 Comparative Example 4 + + CND (0.5 g / L) i _k = 0.5 - 13.0 0.0002 2.8 none i _k = 1.5 2.22 12.4 0.0003 2.2 none  Example 13 Comparative Example 4 + + CND + DND (0.1 / 0.1 g / L) i _k = 0.5 - 12.8 0.0002 2.1 none i _k = 1,5 2.6 14.7 0.0003 2.1 none  Example 14 Comparative Example 4 + + CND + DND (0.5 / 0.5 g / L) i _k = 0,5 - 12,3 0,0005 2,6 none i _k = 1.5 2.3 12.8 0.0002 2.7 none

According to Tables 1 to 3, whisker generation was completely suppressed when using the tin-nanodiamond composite plating solution of the present invention containing nanodiamonds (ND, ND + DND), and only a slight whisker was generated under pure DND conditions. It was. In addition, it can be seen that the use of nanodiamonds greatly reduced the pores of the plating, reduced corrosion resistance, and improved wettability.

Although a preferred embodiment of the present invention has been described in detail above, it is apparent to those skilled in the art that various modifications and changes are possible within the technical spirit of the present invention, and such modifications and modifications belong to the appended claims. .

In the tin-nanodiamond composite plating solution of the present invention, nanodiamonds are dispersed in a tin-plated electrolyte, so that even if tin plating is carried out by electrolytic method, whisker generation can be completely prevented or significantly reduced, and the pores of the plating are greatly reduced to reduce corrosion. Reduced resistance and improved wettability can replace tin-lead plating in the electronic components industry.

Claims (15)

A tin-nanodiamond composite plating solution comprising a tin plated electrolyte comprising a tin ion supply compound, at least one organic acid or a basic compound, and nanodiamonds dispersed in the tin plated electrolyte. The tin of claim 1, wherein the organic acid is selected from the group consisting of sulfonic acid, sulfuric acid and sulfamic acid, hydrochloric acid, citric acid, boric acid, succinic acid, malic acid, acetic acid, phenolsulfonic acid, alkylsulfonic acid, and alkanolsulfonic acid. -Nanodiamond composite plating solution. The tin-nanodiamond composite plating solution according to claim 1, wherein the basic compound is selected from the group consisting of carbonate salt, hydroxide salt and cyanide salt. The tin-ion compound according to claim 1, wherein the tin ion supply compound is selected from the group consisting of eutectic acid-based tin, organosulfate-based tin, organic sulfamic acid-based tin, boron fluoride, tin chloride, and tin oxide. Nanodiamond composite plating solution. The tin-nanodiamond composite of claim 1, wherein the nanodiamond is a nanodiamond particle, a nanodiamond made by an explosive synthesis method, or a nanodiamond mixed with a nanodiamond particle and a nanodiamond made by an explosive synthesis method. Plating solution. The tin-nanodiamond composite plating solution according to claim 5, wherein the particle size of the nanodiamond particles is 1 to 500 nm, and the particle size of the nanodiamonds by the explosion synthesis method is 1 to 10 nm. The tin-nanodiamond composite plating solution according to claim 1, wherein the nanodiamond is a nanodiamond surface-modified by at least one functional group selected from the group consisting of a hydroxyl group, a carboxyl group, a ketone group and a lactone group. The tin-nanodiamond composite plating solution according to claim 1, wherein the nanodiamond is dispersed at a concentration of 0.01-99 g / L with respect to the tin-plated electrolyte. The tin-nanodiamond composite plating solution according to claim 5, wherein the mixed nanodiamond has a mass ratio of nanodiamond particles and nanodiamonds (DND) by an explosion synthesis method of 99: 1 to 50:50. The method of claim 1, wherein the tin plated electrolyte is ammonium sulfate, polyethylene glycol, polyethylene oxide, ascorbic acid, catechol, glutamic acid, hydroquinone, benzophenone, pyrocatechol, benzaldehyde, hydroxyamine, hypophosphite, A tin-nanodiamond composite plating solution further comprising at least one additive selected from the group consisting of hydrazine. 2. The tin of claim 1, wherein the complex plating solution further comprises at least one selected from the group consisting of bismuth, gold, silver, indium, palladium, ruthenium, rhodium, pentium, iridium, and platinum. -Nanodiamond composite plating solution. Preparing a tin-nanodiamond composite plating solution according to any one of claims 1 to 11; And placing a tin anode plate and a cathode plate in the tin-nanodiamond composite plating solution and applying an electric current to the tin anode plate and the cathode plate to perform electroplating. The tin-nanodiamond composite plating method according to claim 12, wherein the current density of the current applied to the tin anode plate and the cathode plate is 0.05 to 20 A / dm ² . The plating film formed into a film using the tin-nanodiamond composite plating liquid of any one of Claims 1-11. A plating material comprising a plating film formed by using the tin-nanodiamond composite plating solution according to any one of claims 1 to 11.