KR100934401B1 - A chip component having a tin plating liquid, a tin plating method using the tin plating liquid, a tin plating liquid adjusting method, and a tin plating layer formed using the tin plating liquid. - Google Patents

Abstract

An object of the present invention is to provide a tin plating liquid that is hard to cause sludge generation even after long-term storage and has a considerably long solution life. The present invention for achieving the above object is a tin plating solution for tin plating by the electrolytic method, containing 5g / L ~ 30g / L of tin salt as a tin ion source in terms of tin, chelate the tin ions to stabilize It characterized in that it comprises a chelating agent and a pH adjusting agent. The tin plating liquid adjusting method is characterized in that a tin chelate complex is formed by adding methane sulfonic acid tin in a neutral to alkaline solution.

Tin Plating Solution, Sludge

Description

Tin Plating Solution, Tin Plating Method Using The Tin Plating Solution, Tin Plating Solution Adjustment Method, And Chip Component With Tin Plating Layer Formed Using The Tin Plating Solution {TIN PLATING SOLUTION, PLATING METHOD USING THE TIN PLATING SOLUTION, METHOD FOR PREPARING TIN PLATING SOLUTION AND CHIP PARTS HAVING TIN PLATING LAYER FORMED BY USING THE TIN PLATING SOLUTION}

The present invention relates to a tin plating liquid, a plating method using the tin plating liquid, and a chip component in which a tin plating layer is formed using the tin plating liquid. In particular, it relates to a tin plating liquid in which sludge which appears in a conventional tin plating liquid does not occur.

Conventionally, tin plating liquid has been widely used as terminal plating and oxidative corrosion prevention plating in the field of electronic component materials. In recent years, the solder may be replaced with a tin plating liquid in accordance with a demand for solder that does not use lead.

In the technical field using a tin plating liquid, in the field of the multilayer ceramic capacitor which is a chip component, it is common to form a tin plating layer on the external electrode surface of this multilayer ceramic capacitor. The tin plating layer of the external electrode of the said laminated ceramic capacitor is excellent in solder wettability, and is useful when surface-mounting on a printed wiring board through surface mounting processes, such as solder reflow.

However, as is widely known in the art, there has been a problem in that tin plating liquid has conventionally precipitated tin oxide (above and hereinafter referred to simply as "sludge") and thus lacks long-term stability. Accordingly, the tin plating solution needed to be used immediately after bathing. In addition, since the tin plating liquid lacking long-term storage property changes every time during the plating operation, the properties and state of the plating liquid change, it is difficult to stabilize the quality of the obtained plating film, and it is extremely difficult to guarantee the quality of the plating liquid. . The tin plating solution with the shortest lifespan may have sludge generated immediately after bathing, causing the tin plating liquid to become cloudy.

Conventionally, although tin plating liquid of the composition as disclosed in patent document 1 exists, there existed a fault which the solution cost as a plating liquid is short, bath management was difficult, and management cost increased. Moreover, tin plating liquid like the one used by patent document 2 also exists. However, the tin plating liquid manufactured according to the manufacturing method described in such a patent document produces sludge almost certainly after 24 hours on average on environmental conditions of about room temperature.

Patent Document 1: Japanese Patent Application Laid-Open No. 10-245694

Patent Document 2: Japanese Patent Application Laid-Open No. 2-170996

Patent Document 3: Japanese Patent Application Laid-Open No. 2001-110666

Problem to be solved of the invention

However, in the tin plating layer formed using the tin plating solution in which sludge has been generated, dewetting of solder generally occurs because the solder wettability to the tin plating layer is inferior to the common defect. In addition, when the tin plating liquid in which the sludge generate | occur | produced is used, uniform film formation of a tin plating layer will become difficult. In addition, when the tin plating liquid in which the sludge has been generated is continuously used in the plating apparatus, various pipes are exerted to make it difficult to maintain the apparatus.

Conventionally, various methods for preventing sludge generation of tin plating liquid have been studied among those skilled in the art. As a result, no effective solution was found other than the method using a large amount of ammonia as disclosed in Patent Literature 3, and the sludge generation was recognized as a characteristic of the tin plating solution, and the level was almost abandoned.

In addition, the drawback of the tin plating liquid using a large amount of ammonia components is that the odor generated by the ammonia is a problem, which directly deteriorates the working environment and promotes corrosion of copper products and copper parts near the plating bath. There is a problem, and active investment was difficult because it requires a facility investment to ventilate the mist inside the plating bath.

In such a situation, if the solution life after the bath is long, the long-term preservation is excellent, and the tin plating liquid can be provided without changing the quality even during a long plating operation, its social applicability will be immeasurable.

Challenge solution

As a result of diligent research, the inventors have invented the following tin plating solutions.

The present invention for solving the above problems is a tin plating solution for tin plating by the electrolytic method, containing 5 g / L to 30 g / L of tin salt as a tin ion source in terms of tin, chelates and stabilizes tin ions By providing a chelating agent and a pH adjuster, there is provided a tin plating solution characterized in that sludge does not occur for more than 7 days.

In addition, the tin salt provides a tin plating solution, characterized in that one or two or more selected from the first tin salt soluble in water.

In addition, the chelating agent is a tin plating solution, characterized in that one or two or more selected from gluconic acid, gluconate, citric acid, citrate, pyrophosphate, pyrophosphate to be 30g / L ~ 300g / L concentration To provide.

In addition, the pH adjuster is an alkaline pH adjuster, it provides a tin plating solution, characterized in that one or two or more selected from sodium hydroxide, potassium hydroxide, ammonia water is contained so as to have a concentration of 5g / L ~ 140g / L.

In addition, the pH adjusting agent is an acidic pH adjusting agent, characterized in that one or two or more selected from methane sulfonic acid, ethane sulfonic acid, sulfuric acid, isethionic acid is contained so that the concentration of 10g / L ~ 300g / L. Provide a tin plating solution.

In addition, it provides a tin plating solution, characterized in that the antioxidant is further included so that the concentration is 0.1g / L ~ 30g / L.

In addition, the pH adjusting agent is for finely adjusting the pH of the tin plating solution to the acidic side, and is one or two of methane sulfonic acid and sulfuric acid, and includes one or two of methane sulfonic acid and sulfuric acid. A tin plating liquid is provided which is in the range of 10.

In addition, the pH adjusting agent is for fine-adjusting the pH of the tin plating solution toward the alkali side, and includes one or two kinds of sodium hydroxide, potassium hydroxide and ammonia water, and includes one or two kinds of sodium hydroxide, potassium hydroxide and ammonia water. By providing a tin plating liquid, pH is in the range of 4-10.

In addition, it provides a tin plating solution, characterized in that it further comprises one or two or more selected from sodium sulfate and ammonium sulfate as the conductive salt so as to have a concentration of 1 g / L to 150 g / L.

In addition, it provides a tin plating solution, characterized in that it further comprises one or two or more selected from nonionic surfactants, cationic surfactants and amphoteric surfactants to a concentration of 0.1 g / L to 30 g / L as a brightening agent.

The present invention also provides a tin plating method characterized by electrolysis under conditions of a bath temperature of 10 ° C to 40 ° C by a tin plating method using the above-described tin plating solution.

The present invention also provides a method for adjusting the above-described tin plating liquid,

A) Mixing water, pH adjuster and chelating agent to prepare a mixed solution having a pH value of 6-12,

B) A tin plating solution adjustment method is prepared by adding a tin salt to the mixed solution so that the tin content is 5 g / L to 30 g / L and stirring sufficiently to form a tin chelate complex.

The present invention also provides a tin plating liquid adjusting method further comprising the step of adding an antioxidant to the tin plating liquid.

The present invention also provides a tin plating liquid adjusting method further comprising the step of fine-adjusting the pH value of the tin plating liquid.

In addition, there is provided a tin plating liquid adjusting method further comprising the step of adding a conductive salt to the tin plating liquid.

The present invention also provides a tin plating liquid adjusting method further comprising the step of adding a polishing agent to the tin plating liquid.

The present invention also provides a chip component comprising a tin plating layer using the above-described tin plating solution.

Effects of the Invention

Even if the tin plating liquid according to the present invention does not contain a large amount of ammonia, precipitation of tin oxide does not easily occur, and the solution life after drying is long, so that it is easy to manage as a plating liquid. In addition, since the tin plating liquid can be used in the neutral region, it does not damage ceramics, electrodes, or the like of electronic components.

In addition, the tin plating using the tin plating liquid according to the present invention can be used at bath temperatures of more than 30 ℃, and because there is a suitable liquid evaporation, it does not cause a significant increase in the amount of waste water can reduce the load of the waste water treatment.

In addition, the method of adjusting the tin plating liquid according to the present invention does not require a special apparatus and method, and a pH adjusting agent and a chelating agent are mixed, methane sulfonic acid is added as a conducting salt, and then mixed and stirred to mix a neutral to alkaline solution. After preparing in advance, tin methane sulfonic acid is added to efficiently form a tin chelate complex in the neutral to alkaline region. Thus, a tin plating solution with a long solution life can be obtained without precipitation of tin oxide.

In addition, by using the tin plating solution and the tin plating method according to the present invention, it is possible to form a tin plating layer having excellent post-film uniformity on the surface of chip components such as a multilayer ceramic capacitor and having a more stable quality even during a long plating operation.

Best for the Invention of  shape

EMBODIMENT OF THE INVENTION Hereinafter, embodiment which concerns on this invention is described in order of a tin plating liquid, a tin plating method, a tin plating liquid adjustment method, and a chip component.

Embodiment of Tin Plating Solution: The tin plating solution according to the present invention contains 5 g / L to 30 g / L of tin salt as a tin ion source as described above in terms of tin, and a chelating agent and pH for chelation of the tin ions to stabilize it. Including a modifier, sludge does not arise more than 7 days. In the tin plating solution supplied to the conventional market, except for the tin plating solution using a large amount of ammonia, sludge is generated within 5 days after bathing, and thus the nature and state of the tin plating solution change. Cause quality deterioration. Therefore, since the replacement work of the tin plating solution is required every short period of time, the cost increases, which is a big problem from the viewpoint of the stable operation of the tin plating. In this regard, the tin plating liquid according to the present invention will be described in detail in the following tin plating liquid adjusting method, but by including a chelating agent and a pH adjusting agent that chelate and stabilize tin ions, the tin plating liquid in the neutral region to the alkaline region (pH 6 to pH 12) By chelation, most of the tin ions are contained as tin complex chelates. As a result, since tin is stabilized as a tin complex chelate in the tin plating liquid, even if it has any structure as described below, the effect that cannot be achieved in the conventional tin plating liquid, that is, sludge in the temperature range of 10 ° C to 40 ° C is 7 It may have an effect that does not occur more than one day. In Examples mentioned later, tin plating liquid which is excellent in solution stability and does not generate a sludge even after 365 days at the temperature of 40 degreeC is disclosed.

In this specification, the tin salt which is a tin ion supply source of a tin plating liquid is a 1st tin salt soluble with water (henceforth only a "tin salt".). And among the said tin salts, it is preferable that they are 1 type, or 2 or more types chosen from methane sulfonic acid tin, tin sulfate, tin sulfamic acid tin, and pyrophosphate tin. Moreover, it is preferable that tin salt content in the tin plating liquid which concerns on this invention is contained in 5 g / L-30 g / L in conversion of tin. When the tin salt content is less than 5 g / L in terms of tin, the current efficiency is lowered, and the plating rate does not satisfy the industrially required productivity, and the smoothness and post-film uniformity of the tin plating layer are impaired. In addition, when the content of tin salt exceeds 30 g / L in terms of tin, the amount of tin in the plating solution increases, so that the electrodeposition rate of tin is too fast, making it difficult to control the thickness of the plating layer, and at the same time, precipitation of tin oxide cannot be avoided. And it is more preferable to make content of tin salt in the tin plating liquid concerning this invention contain 10 g / L-20 g / L in conversion of tin. In order to produce industrially, it is common to have a certain level of fluctuation depending on the plating conditions when using tin salts, and to take into account unavoidable fluctuations that cannot be managed under the plating conditions, it is possible to form a tin plating layer of more stable quality. Because.

Next, the chelating agent stabilizes the tin ions supplied from the tin salt in the tin plating solution as a chelate complex. The chelating agent of the present invention preferably contains one or two or more selected from gluconic acid, gluconate, citric acid, citrate, pyrophosphoric acid and pyrophosphate so as to have a concentration of 30 g / L to 300 g / L. This is because such chelating agents efficiently form chelate complexes with tin ions that are ionized in solution from tin salts, which are a source of tin ions. Especially, using sodium gluconate or citric acid can form the most stable tin chelate complex, the tin oxide is excellent in the precipitation prevention effect, and the tin plating liquid with the longest solution life can be obtained. Here, the chelating agent concentration in the tin plating liquid is originally determined according to the type of chelating agent and the amount of tin in the plating liquid. However, even if any of the above chelating agents are used, the concentration of the chelating agent is in the range of 100 g / L to 200 g / L, and this is used as a generalized notation. And when using 2 or more types of chelating agents together, it is preferable that 2 or more types of chelating agents total concentration is 100g / L-200g / L concentration range. If the chelating agent concentration is less than 100 g / L, it is difficult to form a chelating complex with the entire tin ions in the plating liquid, assuming that the amount of tin in the plating liquid is present, and the generation of tin oxide cannot be prevented because free tin ions are present. . On the other hand, when the concentration of the chelating agent exceeds 200 g / L, the amount of the chelating agent becomes excessive in the formation of the chelating complex with tin ions in the plating solution, which wastes resources.

The pH adjusting agent is used to change the solution from the neutral to the alkaline region so that the tin ions supplied from the tin salt in the tin plating solution react with the chelating agent to form a tin chelate complex, and also, once produced, There are two reasons for the use of stabilization so that the tin plating solution according to the invention finally has a pH suitable for tin plating.

In the present specification, for the sake of explanation, the former is referred to simply as "pH regulator", and the latter is referred to as "pH regulator for fine adjustment". Said "pH regulator" and "pH regulator for fine adjustment" are not added simultaneously. The pH adjuster includes an alkaline pH adjuster and an acidic pH adjuster. The use method of such a pH adjuster etc. are explained in full detail in the following adjustment method. Here, the kind and function of a pH adjuster are demonstrated.

The alkaline pH adjuster according to the present invention may be one or two or more selected from sodium hydroxide, potassium hydroxide and ammonia water. The reason why these are selected as the alkaline pH adjuster is that when the tin plating is performed, a good tin plating layer can be formed without affecting the properties and states of the plating liquid. The alkaline pH adjuster promotes the ring opening of the chelating agent to facilitate the chelation of the chelating agent and the tin ions, and more specifically, the alkaline pH adjusting agent is included in a concentration of 5 g / L to 140 g / L. When the alkaline pH adjusting agent is included at less than 5 g / L, the ring opening of the chelating agent cannot be promoted. In addition, when the alkaline pH adjuster is added in excess of 140 g / L, the ring-opening efficiency of the chelating agent is not improved, and when the content range of the tin salt is considered, the addition is excessive. This range enables stable chelation of tin salts and tin ions to be added later, and also facilitates pH adjustment by the following acidic pH adjusters.

The acidic pH adjuster used in combination with the alkaline pH adjuster includes one or two or more selected from methane sulfonic acid, ethane sulfonic acid, sulfuric acid, and isethionic acid at a concentration of 10 g / L to 300 g / L. The reason why these are selected as the acidic pH adjusting agent is that when tin plating is performed, a good tin plating layer can be formed without affecting the properties and states of the plating solution. And, the acidic pH adjuster, by changing the pH value of the plating liquid during the adjustment already having an alkaline region by the alkaline pH adjuster to a neutral to weak alkali region in the range of 6 to 12, in this state to form a tin chelate It is to stabilize. If an acidic pH adjuster is added in excess of 300 g / L, the pH of the plating liquid during the adjustment will be less than 6, which will not stabilize the tin ion chelate, and the final tin plating liquid will generate sludge early. On the other hand, when the acidic pH adjuster is added below 10 g / L, the pH of the plating liquid belongs to a strong alkali region in which the plating liquid exceeds 12 during the adjustment. Therefore, it is difficult to finely adjust the tin plating liquid, resulting in a tin plating liquid that is easily eroded with the ceramic. .

Next, as the pH adjusting agent for fine adjustment, the pH adjusting agent (hereinafter referred to as "microadjusting acidic pH adjusting agent") for finely adjusting the pH of the tin plating liquid according to the present invention to the acidic side and the pH of the tin plating liquid according to the present invention are used. There exists a pH adjuster (henceforth "alkaline pH adjuster for fine adjustment") for fine adjustment to an alkaline side. Such fine adjustment pH adjuster is added as needed, and is used for final pH adjustment of a tin plating liquid. Therefore, the timing of the addition is preferably used in the step after generating and stabilizing the tin chelate.

In addition, it is preferable to make the pH value of a plating liquid into the range of 4-10, More preferably, the range of 6-8 is used as 1 type or 2 types of methane sulfonic acid and sulfuric acid as a fine adjustment acidic pH adjuster. In addition, it is preferable to make the pH value of a plating liquid into the range of 4-10, More preferably, it is the range of 6-8 using 1 type or 2 types of sodium hydroxide, potassium hydroxide, ammonia water as a fine adjustment alkaline pH adjuster. Do. When the pH value of the tin plating solution becomes less than 4 strongly acidic regions, the possibility of eroding ceramic parts used for chip parts such as multilayer ceramic capacitors for tin plating increases. Further, even when the pH value of the tin plating solution becomes a strongly alkaline region of more than 10, the ceramic portion may also be eroded. At the same time, since the stability of the produced tin chelate complex is impaired, the tin cannot be immobilized and becomes tin ions, resulting in precipitation of tin oxide, resulting in shortening of the solution life of the tin plating solution. Therefore, a more preferable range is suitable for approaching the neutral region for reliably preventing ceramic erosion by the tin plating liquid and ensuring long life of the tin plating liquid.

It is also preferable to include an antioxidant in the tin plating liquid according to the present invention from the viewpoint of prolonging the life of the tin plating liquid. This is because natural oxidation due to contact between the atmosphere and the plating liquid is prevented and precipitation of tin oxide is effectively prevented. It is preferable to include the antioxidant to be 0.1g / L ~ 30g / L concentration. And among antioxidants, it is preferable to use 1 type, or 2 or more types chosen from catechol, hydroquinone, ascorbic acid, ascorbic acid salt, and phenylene diamine. When the concentration of the antioxidant is less than 0.1 g / L, a sufficient antioxidant effect cannot be obtained. Further, even if the concentration of the antioxidant is added in excess of 30 g / L, no further antioxidant effect is obtained, and the long life of the tin plating solution cannot be expected. In addition, excessive addition of an antioxidant is not preferable because a change in the quality of the tin plating liquid occurs. Therefore, the more preferable concentration of antioxidant is the range of 1 g / L-10 g / L. It is because it is possible to obtain a definite antioxidant effect and to reliably prevent the quality change of the tin plating liquid due to the excessive addition of the antioxidant.

The tin plating liquid according to the present invention can be electrolyzed even with the above composition without adding a conductive salt. However, when it is necessary to further stabilize the energized state when electrolyzing the tin plating solution, increase the current efficiency of the precipitation of tin, and increase the productivity, it is preferable to further add a conductive salt. When it is necessary to add a conductive salt, it is preferable to include 1 type, or 2 or more types chosen from sodium sulfate and ammonium sulfate so that it may become 1 g / L-150 g / L concentration. Here, the reason why sodium sulfate and ammonium sulfate are used as the conductive salt is because the quality change of the tin plating solution is smallest when using these, and there is no impurity residue in the tin plating layer. When the addition amount of the said conductive salt is less than 1 g / L, the effect which improves electricity supply stability is not acquired when electrolytically is performed. Moreover, even if the addition amount of the said conductive salt exceeds 150 g / L, the electricity supply stability at the time of electrolysis does not improve more than that, and it wastes a resource.

In addition, the tin plating liquid according to the present invention preferably contains one or two or more selected from nonionic surfactants, cationic surfactants and amphoteric surfactants as a brightening agent so as to have a concentration of 0.1 g / L to 30 g / L. Since the said gloss agent smoothes the tin plating layer obtained by electrolyzing a tin plating liquid, it contributes to the improvement of post-film uniformity.

In more detail, the nonionic surfactant is a surfactant having a hydrophilic group that does not ionize in water, so it is difficult to be affected by the hardness of the water or the electrolyte, and it may be used in combination with all other surfactants. It is possible. Nonionic surfactants are classified into ester type, ether type, ester ether type and others according to their structure, but the tin plating solution according to the present invention includes higher alcohols, alkyl phenols, fatty acids, amines, alkylene diamines, fatty acid amides and sulfones. It is preferable to use 1 type, or 2 or more types among polyoxy alkylene adducts of amide (sulfonamide), polyhydric alcohol, and glucoside.

The cation surfactant is a surfactant having a property in which a part having a hydrophobic group in water is ionized to a cation. Therefore, a cation surfactant generally has a property of being strongly adsorbed on a solid surface charged to a negative portion. As the cationic surfactant that can be used in the tin plating solution according to the present invention, specifically, lauryl trimethyl ammonium salt, cetyltrimethylammonium salt, stearyl trimethyl ammonium salt, lauryl dimethyl ethyl ammonium salt, octadecenyldimethylethyl ammonium salt, lauryl dimethyl ammonium beta Phosphorus, stearyl dimethyl ammonium betaine, dimethyl-benzyl lauryl ammonium salt, cetyldimethylbenzyl ammonium salt, octadecyl dimethyl benzyl ammonium salt, trimethyl benzyl ammonium salt, triethyl benzyl ammonium salt, hexadecylvirinium salt, laurylvirinium salt, dodecyl picoli It is preferable to use one or two or more selected from nium salt, lauryl imidazolinium salt, oleyl imidazolinium salt, stearyl amine acetate, lauryl amine acetate and octadecyl amine acetate.

In addition, an amphoteric surfactant is a surfactant which exhibits the properties of an anionic surfactant in an alkaline region and a cationic surfactant in an acidic region when dissolved in water. As an amphoteric surfactant which can be used for the tin plating liquid which concerns on this invention, using the 1 type (s) or 2 or more types chosen from the alkyl carboxy betaine type, the alkylamino carboxylic acid type, and the alkyl imidazoline type is used. desirable.

It is most preferable to use either lauryl dimethyl amino acetic acid betaine or polyoxyethylene lauryl ether among surfactant as said brightening agent. This is because such a surfactant is excellent in stability in the tin plating solution, has a high effect of improving the solution life of the tin plating solution, and also has a high effect on the post-film uniformity of the formed plating film.

When the concentration of the surfactant as a gloss agent is less than 0.1 g / L in the tin plating solution, the tin plating layer is smoothed and the post-film uniformity cannot be obtained. On the other hand, even if the concentration of the brightener exceeds 30 g / L, the effect of smoothing the tin plating layer and improving the post-film uniformity does not improve further.

Embodiment of Tin Plating Method: The tin plating method using the tin plating liquid according to the present invention is preferably electrolyzed under conditions of a bath temperature of 10 ° C to 40 ° C. The plating method is characterized in that the plating operation is possible in the range of bath temperature 10 ℃ ~ 40 ℃. When the bath temperature is less than 10 ° C., internal distortion is severe, thick tin plating crystals are precipitated, and it is difficult to obtain a tin plating layer excellent in uniformity after film formation by smoothing. On the other hand, when the bath temperature exceeds 40 ° C, evaporation of moisture in the plating liquid becomes remarkable, and the variation in the composition of the tin plating liquid is intense, and the solution life is also shortened.

Conventional tin plating liquids lack plating solution stability as a plating liquid and have a short solution life. Therefore, plating operation has to be performed at a bath temperature of about room temperature. In this regard, the tin plating liquid according to the present invention is capable of tin plating operation even in a high temperature region where the bath temperature exceeds 30 ° C. As described above, when the plating operation is performed at a bath temperature of 30 ° C to 40 ° C, moisture in the plating liquid is properly evaporated to reduce the amount of plating wastewater in a range that does not deteriorate the quality of the tin plating liquid, thereby reducing the load of the wastewater treatment.

In this case, the current density is preferably in the range of 0.05 A / dm ² to 0.5 A / dm ² . The current density is 0.05A / dm ² If less, the precipitation rate of tin is naturally slow, and industrial productivity is not satisfied. Moreover, when exceeding 0.5 A / dm <^2> , the smoothness of a tin plating film will be impaired.

Embodiment of the tin plating liquid adjusting method: The tin plating liquid adjusting method according to the present invention is characterized by the following procedures A and B. This tin plating liquid adjusting method is characterized in that tin salt is added to an aqueous solution in a neutral to alkaline region containing a chelating agent to form a tin chelate complex.

In the step A), water, a pH adjuster and a chelating agent are mixed to prepare a premixed solution having a pH value of 6-12. Since the kind and content of the "pH regulator" and the "chelating agent" here were mentioned above, description is abbreviate | omitted in order to avoid duplication of description. Therefore, the adjustment procedure is mainly described.

First, a pH adjuster and a chelating agent are added to a predetermined amount of water such as ion-exchanged water and pure water, followed by mixing with sufficient stirring. At this time, the order of adding the pH adjusting agent and the chelating agent is not particularly limited. However, in the case of using sodium hydroxide particles, it is preferable to dissolve the sodium hydroxide particles that take a certain time to dissolve first and then add a chelating agent. As described above, the pH adjuster includes an alkaline pH adjuster and an acidic pH adjuster. Although there is no special restriction regarding the order of addition, etc., It is preferable to add in order of an alkaline pH adjuster and an acidic pH adjuster. The alkaline pH adjusting agent promotes the ring opening of the chelating agent so that the chelating agent and the tin ions are easily chelated. Accordingly, after the ring-opening of the chelating agent, the pH value of the plating liquid in the adjustment made into the alkaline region is once stabilized by generating tin chelate in the weak alkali region from the neutral region in the range of 6 to 12 using the acidic pH adjusting agent. This is because it is preferable.

In the step B), a tin plating solution is prepared by adding a tin salt to the premixed solution so that the tin content is 5 g / L to 30 g / L and stirring sufficiently to form a tin chelate complex. At this time, the tin salt is added to the premixed solution so as to have a concentration of 5 g / L to 30 g / L in terms of tin and sufficiently stirred to complete the adjustment of the tin plating solution according to the present invention having a basic configuration. The adjustment process of the said tin plating liquid is assumed to be performed at room temperature. Thereafter, it is also preferable to additionally perform the following steps.

It is also preferable to add the process of adding antioxidant to the adjusted tin plating liquid. The antioxidant is as described above, and is added so that the concentration of the antioxidant in the tin plating solution is 0.1 g / L to 30 g / L. The addition method is not particularly limited.

In addition, when the pH value of the tin plating liquid obtained by the said process deviated from the suitable range, the pH value of a plating liquid may be 4-10, more preferably 6-8 using the above-mentioned acidic pH adjuster for fine adjustment mentioned above. It is preferable to perform the pH fine adjustment process which will be in the range. The fine adjustment pH adjusting agent includes the fine adjustment alkaline pH adjusting agent and the fine adjustment acidic pH adjusting agent.

In the tin plating solution according to the present invention, when it is necessary to further stabilize the energized state when electrolyzing the tin plating solution, increase the current efficiency of the precipitation of tin, and increase the productivity, a step of additionally adding a conductive salt is carried out after the It is preferable to carry out. At this time, it is preferable to include 1 type (s) or 2 or more types chosen from the said sodium ammonium sulfate as a conductive salt so that it may become 1 g / L-150 g / L concentration.

In addition, in the tin plating solution according to the present invention, in order to smooth the tin plating layer obtained by electrolyzing the tin plating solution and to improve film thickness uniformity, it is also preferable to perform a step of adding a brightening agent afterwards. It is preferable that the said brightening agent contains 1 type (s) or 2 or more types chosen from the above-mentioned nonionic surfactant, cationic surfactant, and amphoteric surfactant so that it may become 0.1g / L-30g / L concentration.

Embodiment of chip components: The tin plating solution according to the present invention is a tin plating layer of chip components such as chip type multilayer ceramic capacitors, chip type ceramic coils, chip type ceramic thermistors, inductors, varistors, resistors, etc., in which tin plating is widely used among electronic components. It is very suitable to form.

1 is an SEM observation image of the tin plating layer formed using the tin plating solution according to the present invention after 365 days from the bath.

FIG. 2 is an SEM observation image of the tin plating layer formed using the tin plating solution according to the present invention after 365 days from the bath.

3 is an SEM observation image of the tin plating layer formed using the tin plating solution according to the present invention after 365 days from the bath.

4 is an SEM observation image of a tin plating layer formed using a tin plating solution in which sludge has elapsed after two days from the drying bath.

5 is an SEM observation image of a tin plating layer formed using a tin plating solution in which sludge has been generated in a step of drying.

FIG. 6 is an SEM observation image of a tin plating layer formed by using a tin plating solution in which sludge has elapsed after two days from the drying bath.

Example  One

In this example, the tin plating solution was adjusted through the following steps I to V.

Step I: Sodium gluconate was added to the ion-exchanged water as a chelating agent, and then granular sodium hydroxide was dissolved with an alkaline pH adjuster. Thereafter, methane sulfonic acid at a concentration of 70 wt% was added as an acidic pH adjuster to obtain a premixed liquid having a pH of 12.

Step II: A tin plating solution having a basic composition was prepared by adding methane sulfonic acid tin to the premixed solution to cause a chelation reaction and forming a tin chelate complex.

Step III: Sodium hydroxide, which is an unadjusted alkaline pH adjuster, was added to the unadjusted pH adjuster so that the pH of the final tin plating solution was 4.0.

IV process: Ascorbic acid was added to this tin plating liquid as antioxidant, and it stirred and mixed.

V process: After that, lauryl dimethyl amino beta acetate was added as a brightening agent, and it stirred and mixed. As a result, a tin plating liquid of the following composition was obtained.

(Tin plating solution composition)

Methane sulfonic acid tin (tin equivalent): 14 g / L

Sodium Hydroxide: 42g / L

Sodium Gluconate: 120g / L

Methane sulfonic acid: 135 g / L

Ascorbic acid: 3 g / L

Lauryl Dimethyl Amino Betaine: 1g / L

pH: 4.0

(Long-term preservation evaluation of tin plating solution)

The tin plating liquid was stored in an atmospheric atmosphere at room temperature. As a result, even after 365 days, sludge did not generate | occur | produce. In addition, even if the tin plating solution added sodium hydroxide to a pH value of 10, no sludge was generated after 365 days. And even if the temperature of the liquid was 40 degreeC, the sludge did not generate | occur | produce on the same conditions.

(Observation of tin plating layer)

A nickel layer having a thickness of 2 μm was formed on the surface of the copper external electrode of the multilayer ceramic capacitor having a size of 2 mm × 1.2 mm in 2012, and the tin plating solution was electrolyzed under a current density of 0.1 A / dm ² and a bath temperature of 30 ° C. A test sample was prepared by forming a tin plating layer having a thickness of 5 μm on the surface of the nickel layer. And the surface of the said tin plating layer was observed in SEM (scanning electron microscope), and is shown in FIG. As apparent from the comparison with the comparative example, no abnormal precipitation appeared and the surface was uniformly coated.

(Solder wettability evaluation)

In the case of a tin plating layer formed on the surface of an external electrode or the like of a multilayer ceramic capacitor, the solder wettability of the tin plating layer becomes very important considering that these chip components are surface mounted on a printed wiring board or the like. Here, a 20% rosin-iso propanol solution was applied as a flux to the test sample, and SWET-2100 (solder bath temperature 215 ° C, 6/4 solder) manufactured by Tartinkesta Co., Ltd. was used. The test was conducted by solder paste equilibrium method (quick heating mode). Here, a pressure cooker test (2 atm, 105 DEG C, 100% RH, 4 hours) was performed on the test sample, and the characteristics before and after the evaluation were evaluated. As a result, all of the solder wettability was good with a zero cross time of 2 seconds or less. Indicated.

Example 1 above is in contrast with Comparative Example 1 described later. Therefore, in Table 1, it is shown comprehensively so that the comparative example 1 and the tin plating liquid composition order of the said Example 1, the presence or absence of sludge generation, solder wettability, etc. can be contrasted.

Example  2

In this example, the same steps as in Example 1 to V are carried out in the same manner as in Example 1, and the pH 12 is prepared by sequentially mixing sodium gluconate as a chelating agent, sodium hydroxide as an alkaline pH regulator, and methane sulfonic acid as an acidic pH regulator. A mixed solution was prepared, to which methane sulfonic acid tin was used as a tin salt, sodium hydroxide as an alkaline pH adjuster for fine adjustment, ascorbic acid as an antioxidant, and lauryl dimethyl amino acetate betaine as a brightener were added sequentially, and a tin plating solution having the following composition Was adjusted.

(Tin plating solution composition)

Methane sulfonic acid tin (tin equivalent): 20 g / L

Sodium Hydroxide: 31g / L

Sodium Gluconate: 150g / L

Methane sulfonic acid: 68 g / L

Ascorbic acid: 3 g / L

Lauryl Dimethyl Amino Betaine: 1g / L

pH: 6.0

(Long-term preservation evaluation of tin plating solution)

The tin plating liquid was stored in an atmospheric atmosphere at room temperature. As a result, there was no sludge generation even after elapse of 365 days. Moreover, even if sulfuric acid or sodium hydroxide was added to the said tin plating liquid, and pH value was changed to the range of 4-10, there was no sludge generation after 365 days. In addition, even when the temperature of the liquid was 40 ° C, no sludge was generated in the same shipbuilding.

(Observation of tin plating layer)

As in Example 1, when the surface state was observed using the SEM, a very good uniform surface was provided. Since this observation image is the same as in Example 1, the publication is omitted.

(Solder wettability evaluation)

As in Example 1, the characteristics before and after the pressure cooker test were evaluated, and all showed good solder wetting with zero cross time of 2 seconds or less.

Example 2 described above is compared with Comparative Example 2 described later. Accordingly, Table 2 shows the synthesis procedure of Comparative Example 2 and Example 2 in order to enable contrast between the tin plating solution adjustment procedure, the presence of sludge generation, the solder wettability, and the like.

Example  3

In this example, the same steps as in Example 1 to V are carried out, and sodium ion gluconate as a chelating agent, sodium hydroxide as an alkaline pH adjuster, and methane sulfonic acid as an acidic pH adjuster are sequentially mixed in ion-exchanged water. A mixed solution was prepared, in which methane sulfonic acid tin was used as a tin salt, sodium hydroxide as an alkaline pH adjuster for fine adjustment, ascorbic acid as an antioxidant, and lauryl dimethyl amino acetate betaine as a brightening agent were added sequentially, Was adjusted.

(Tin plating solution composition)

Methane sulfonic acid tin (tin equivalent): 20 g / L

Sodium Hydroxide: 35g / L

Sodium Gluconate: 150g / L

Methane sulfonic acid: 68 g / L

Ascorbic acid: 3 g / L

Lauryl Dimethyl Amino Betaine: 1g / L

pH: 8.0

(Long-term preservation evaluation of tin plating solution)

The tin plating liquid was stored in an atmospheric atmosphere at room temperature. As a result, no sludge was generated even after curing for 365 days. Moreover, even if the temperature of the liquid was 40 degreeC, the sludge did not generate | occur | produce on the same conditions.

(Observation of tin plating layer)

As in Example 1, when the surface state was observed using SEM, it had a very good uniform surface. Since this observation image is the same as in Example 1, the publication is omitted.

(Evaluation of Solder Wetting)

As in Example 1, the characteristics before and after the pressure cooker test were evaluated, and all showed good solder wetting with zero cross time of 2 seconds or less.

Example 3 above is in contrast with Comparative Example 3 described later. Therefore, in Table 3, the tin plating solution adjustment procedure of the comparative example 3 and the said Example 3, the presence or absence of the sludge generation, the solder wettability, etc. were compared, and it showed collectively.

Example  4

In this example, the tin plating solution of the following composition was adjusted through the same steps I to V as in Example 1. Others use citric acid instead of sodium gluconate as a chelating agent. That is, a premixed solution of pH 6.0 is prepared by sequentially mixing citric acid with chelating agent, sodium hydroxide with alkaline pH adjusting agent, and methane sulfonic acid with acidic pH adjusting agent, and tin methane sulfonic acid tin and fine adjustment with tin salt. Sodium hydroxide as an alkaline pH adjuster, ascorbic acid as an antioxidant, and lauryl dimethyl amino acetate betaine as a brightening agent were added sequentially, and the tin plating liquid was adjusted.

(Tin plating solution composition)

Methane sulfonic acid tin (tin equivalent): 20 g / L

Sodium Hydroxide: 31g / L

Citric Acid: 150g / L

Methane sulfonic acid: 68 g / L

Ascorbic acid: 3 g / L

Lauryl Dimethyl Amino Betaine: 1g / L

pH: 6.0

(Long-term preservation evaluation of tin plating solution)

The tin plating liquid was stored in an atmospheric atmosphere at room temperature. As a result, there was no sludge generation even after elapse of 365 days. Moreover, even if the temperature of the liquid was 40 degreeC, the sludge did not generate | occur | produce on the same conditions.

(Appearance of tin plating layer)

The surface state was observed using SEM as in Example 1. And the surface of the said tin plating layer was observed with SEM (scanning electron microscope), and the observation image is shown in FIG. It will be clear compared with the comparative example, but abnormal precipitation did not appear and the surface coating was uniform.

(Solder wettability evaluation)

As a result of evaluating the characteristics before and after the pressure cooker test as in Example 1, all showed good solder wetting with zero cross time of 2 seconds or less.

Example 4 above is in contrast with Comparative Example 4 described later. Therefore, in Table 4, the tin plating solution adjustment procedure, the presence or absence of sludge generation, the solder wettability, and the like of Comparative Example 4 and Example 4 were compared.

Example  5

In this example, the tin plating solution of the following composition was adjusted through the steps I to V as in Example 1. The other is to use polyoxy ethylene lauryl ether instead of lauryl dimethyl amino betaine as a brightening agent. That is, a premixed solution of pH 12 was prepared by sequentially mixing sodium gluconate as a chelating agent, sodium hydroxide as an alkaline pH adjusting agent, and methane sulfonic acid with an acidic pH adjusting agent, and tin methane sulfonic acid tin as a tin salt, The tin plating solution was adjusted by sequentially adding sodium hydroxide as a finely adjusted alkaline pH adjuster, ascorbic acid as an oxidation inhibitor, and polyoxyethylene lauryl ether as a brightener.

(Tin plating solution composition)

Methane sulfonic acid tin (tin equivalent): 14 g / L

Sodium Hydroxide: 42g / L

Sodium Gluconate: 120g / L

Methane sulfonic acid: 135 g / L

Ascorbic acid: 3 g / L

Polyoxyethylene lauryl ether: 1 g / L

pH: 4.0

(Long-term preservation evaluation of tin plating solution)

The tin plating liquid was stored in an atmospheric atmosphere at room temperature. As a result, there was no sludge generation even after elapse of 365 days. In addition, even when the temperature of the liquid was 40 ° C, no sludge was generated under the same conditions.

(Observation of tin plating layer)

As in Example 1, as a result of observing the surface state using SEM, a very good uniform surface was provided. Since this observation image is the same as in Example 1, the publication is omitted.

(Solder wettability evaluation)

As in Example 1, as a result of evaluating the characteristics before and after the pressure cooker test, all showed good solder wetting with zero cross time of 2 seconds or less.

The above Example 5 is compared with the comparative example 5 mentioned later. Therefore, in Table 5, it is shown comprehensively so that the contrast of the tin-plating liquid adjustment procedure of the comparative example 5 and the said Example 5, the presence or absence of sludge generation, solder wettability, etc. can be prepared.

Example  6

In this example, the tin plating solution having the following composition was adjusted through the same steps I to V as in Example 1. The other is the use of tin sulfate instead of methane sulfonic acid tin as the tin salt and polyoxyethylene lauryl ether instead of lauryl dimethyl amino beta acetate as the brightener. That is, a premixed solution of pH 12 is prepared by sequentially mixing sodium gluconate as a chelating agent, sodium hydroxide as an alkaline pH adjusting agent, and methane sulfonic acid with an acidic pH adjusting agent, and tin sulfate and fine-adjusting solution as tin salts. Sodium hydroxide as an alkaline pH adjuster, ascorbic acid as an antioxidant, and polyoxyethylene lauryl ether as a brightener were added sequentially, and the tin plating liquid was adjusted.

(Tin plating solution composition)

Tin sulfate (in terms of tin): 14 g / L

Sodium Hydroxide: 42g / L

Sodium Gluconate: 120g / L

Methane sulfonic acid: 135 g / L

Ascorbic acid: 3 g / L

Polyoxyethylene lauryl ether: 1 g / L

pH: 4.0

(Long-term preservation evaluation of tin plating solution)

The tin plating liquid was stored in an atmospheric atmosphere at room temperature. As a result, there was no sludge generation even after elapse of 365 days. Moreover, even if the temperature of the liquid was 40 degreeC, the sludge did not generate | occur | produce on the same conditions.

(Appearance of tin plating layer)

The surface state was observed using SEM as in Example 1. And the surface of the said tin plating layer was observed with SEM (scanning electron microscope), and the observed image is shown in FIG. Although it will be clear compared with a comparative example, abnormal precipitation did not appear and the surface coating was uniform.

(Solder wettability evaluation)

As a result of evaluating the characteristics before and after the pressure cooker test as in Example 1, all showed good solder wetting with zero cross time of 2 seconds or less.

Example 6 above is in contrast with Comparative Example 6 described later. Therefore, in Table 6, the tin plating solution adjustment procedure, the presence or absence of sludge generation, the solder wettability, etc. of Comparative Example 6 and Example 6 were prepared.

Example  7

In this example, the tin plating solution of the following composition was adjusted through the same steps I to V as in Example 1. Others use catechol instead of ascorbic acid as antioxidant and polyoxyethylene lauryl ether instead of lauryl dimethyl amino beta acetate as a brightener. That is, a premixed solution of pH 12 was prepared by sequentially mixing sodium gluconate as a chelating agent, sodium hydroxide as an alkaline pH adjusting agent, and methane sulfonic acid with an acidic pH adjusting agent, and tin methane sulfonic acid tin as a tin salt, Sodium hydroxide as a fine adjustment alkaline pH adjuster, catechol as antioxidant, polyoxyethylene lauryl ether as a brightener were added sequentially, and the tin plating liquid was adjusted.

(Tin plating solution composition)

Methane sulfonic acid tin (tin equivalent): 14 g / L

Sodium Hydroxide: 42g / L

Sodium Gluconate: 120g / L

Methane sulfonic acid: 135 g / L

Catechol: 3 g / L

Polyoxyethylene lauryl ether: 1 g / L

pH: 4.0

(Long-term preservation evaluation of tin plating solution)

The tin plating liquid was stored in an atmospheric atmosphere at room temperature. As a result, there was no sludge generation even after elapse of 365 days. Moreover, even if the temperature of the liquid was 40 degreeC, the sludge did not generate | occur | produce on the same conditions.

(Observation of tin plating layer)

When the surface state was observed using SEM like Example 1, it had a very favorable uniform surface. Since this observation image is the same as in Example 1, the publication is omitted.

(Solder wettability evaluation)

As in Example 1, as a result of evaluating the characteristics before and after the pressure cooker test, all showed good solder wetting with zero cross time of 2 seconds or less.

Example 7 above is in contrast with Comparative Example 7 described later. Therefore, Table 7 was collectively shown so as to enable comparison of the tin plating solution adjustment procedure, the presence or absence of sludge generation, the solder wettability, and the like between Comparative Example 7 and Example 7.

Example  8

In this example, the tin plating solution of the following composition was adjusted through the same steps I to V as in Example 1. The other is adding ascorbic acid as an antioxidant and sodium sulfate as a conductive salt. That is, a premixed solution of pH 12 was prepared by sequentially mixing sodium gluconate as a chelating agent, sodium hydroxide as an alkaline pH adjusting agent, and methane sulfonic acid with an acidic pH adjusting agent, and tin methane sulfonic acid tin as a tin salt, The tin plating solution was adjusted by sequentially adding sodium hydroxide as an unadjusted alkaline pH adjuster, ascorbic acid as an antioxidant, sodium sulfate as a conductive salt, and lauryl dimethyl amino acetate betaine as a brightener.

(Tin plating solution composition)

Methane sulfonic acid tin (tin equivalent): 20 g / L

Sodium Hydroxide: 31g / L

Sodium Gluconate: 150g / L

Methane sulfonic acid: 68 g / L

Ascorbic acid: 3 g / L

Sodium Sulfate: 70g / L

Lauryl Dimethyl Amino Betaine: 1g / L

pH: 6.0

(Long-term preservation evaluation of tin plating solution)

The tin plating liquid was stored in an atmospheric atmosphere at room temperature. As a result, there was no sludge generation even after elapse of 365 days. Moreover, even if the temperature of the liquid was 40 degreeC, the sludge did not generate | occur | produce on the same conditions.

(Observation of tin plating layer)

When the surface state was observed using SEM like Example 1, it had a very favorable uniform surface. Since this observation image is the same as in Example 1, the publication is omitted.

(Solder wettability evaluation)

As in Example 1, as a result of evaluating the characteristics before and after the pressure cooker test, all showed good solder wetting with zero cross time of 2 seconds or less.

The above Example 8 is compared with the comparative example 8 mentioned later. Therefore, Table 8 summarizes the procedures for adjusting tin plating solutions, the presence or absence of sludge generation, solder wettability, and the like of Comparative Example 8 and Example 8.

Comparative Example 1

In Comparative Example 1, the tin plating solution adjustment procedure of Example 1 was changed, and the tin plating solution was adjusted through the following steps (i) to (iv).

I) Process: Sodium gluconate was added to ion-exchanged water as a chelating agent, and methane sulfonic acid at a concentration of 70 wt% was mixed with an acidic pH adjuster to prepare a strongly acidic premixed liquid having a pH of 1 or less.

Ii) Step: Methane sulfonic acid tin was added to the preliminary liquid mixture, and the mixture was sufficiently mixed.

I) Process: Granular sodium hydroxide was dissolved in a premixed solution to which methane sulfonic acid tin was added as an alkaline pH adjusting agent, thereby preparing a tin plating liquid having a basic configuration.

I) Process: Ascorbic acid was added to this tin plating liquid as antioxidant, and it stirred and mixed.

I) Process: Then, lauryl dimethyl amino betaine acetate was added as a brightening agent, and it stirred and mixed. As a result, a tin plating liquid of the composition shown below was obtained.

(Tin plating solution composition)

Methane sulfonic acid tin (tin equivalent): 14 g / L

Sodium Hydroxide: 42g / L

Sodium Gluconate: 120g / L

Methane sulfonic acid: 135 g / L

Ascorbic acid: 3 g / L

Lauryl Dimethyl Amino Betaine: 1g / L

pH: 4.0

(Long-term preservation evaluation of tin plating solution)

The tin plating liquid was stored in an atmospheric atmosphere at room temperature. As a result, two days after bathing, the sludge generate | occur | produced.

(Appearance of tin plating layer)

The surface state was observed using SEM as in Example 1. And the observation image which observed the surface of the said tin plating layer by the SEM (scanning electron microscope) is shown in FIG. It will be clear in comparison with Example 1, but abnormal precipitation was observed on the tin-plated surface, and no uniform surface coating was formed. In addition, the tin plating layer observed here is formed using the tin plating liquid in which the sludge generate | occur | produced.

(Solder wettability evaluation)

As a result of evaluating the characteristics before and after the pressure cooker test as in Example 1, zero cross time was required for 3 seconds or more in order to exhibit good solder wettability.

In order to prepare the above Comparative Example 1 and Example 1, it was simultaneously published in Table 1 to facilitate the respective tin plating solution adjustment procedure, the presence of sludge generation, the contrast of the solder wettability.

TABLE 1

Example 1 Comparative Example 1    Mixed order Solvent: Ion Exchange Water Solvent: Ion Exchange Water ① Sodium Gluconate ① Sodium Gluconate ② Sodium Hydroxide ② Methane sulfonic acid ③ Methane sulfonic acid ③ Methane sulfonic acid tin ④ Methane sulfonic acid tin ④ Sodium Hydroxide ⑤ sodium hydroxide ⑤ Ascorbic acid ⑥ Ascorbic acid ⑥ Lauryl dimethylamino acetic acid betaine ⑦ Lauryl dimethylamino acetic acid betaine    Composition of Tin Plating Solution Methane sulfonic acid tin (tin equivalent): 14 g / L Sodium Hydroxide: 42g / L Sodium Gluconate: 120g / L Methane sulfonic acid: 135 g / L Ascorbic acid: 3 g / L Lauryldimethylaminoacetic acid betaine: 1g / L pH: 4.0 Sludge Occurrence Status No sludge after 365 days Sludge after 2 days SEM observation No precipitation and uniform surface Surface with abnormal precipitation Solder Wetability Rating 2 seconds or less More than 3 seconds

Solder Wetting Evaluation: Solder Paste Equilibrium (Quick Heating Mode)

Comparative Example 2

Comparative Example 2 was subjected to the same ⅴ step ~ ⅴ step as Comparative Example 1, sequentially mixed with sodium gluconate as a chelating agent and methane sulfonic acid with an acidic pH adjuster in ion-exchanged water to prepare a strong acid pre-mixture of pH 1 or less To this, tin methane sulfonic acid tin, sodium hydroxide as an alkaline pH adjuster, ascorbic acid as an antioxidant, lauryl dimethyl amino acetate betaine as a brightener were added sequentially, and the tin plating liquid of the following composition was adjusted.

(Tin plating solution composition)

Methane sulfonic acid tin (tin equivalent): 20 g / L

Sodium Hydroxide: 46g / L

Sodium Gluconate: 150g / L

Methane sulfonic acid: 135 g / L

Ascorbic acid: 3 g / L

Lauryl Dimethyl Amino Betaine: 1g / L

pH: 6.0

(Long-term preservation evaluation of tin plating solution)

The tin plating liquid was stored in an atmospheric atmosphere at room temperature. As a result, when one day passed after bathing, the sludge produced.

(Observation of tin plating layer)

As a result of observing the surface state using the SEM as in Example 1, it was found that abnormal precipitation appeared on the tin-plated surface as in the case of Comparative Example 1, and that a uniform surface coating was not formed. Since this observation image is the same as that in Comparative Example 1, the publication is omitted. In addition, the tin plating layer observed here is formed using the tin plating liquid in which the sludge generate | occur | produced.

(Solder wettability evaluation)

As in Example 1, as a result of evaluating the characteristics before and after the pressure cooker test, zero cross time was required for 3 seconds or more in order to exhibit good solder wettability.

In order to prepare the above Comparative Example 2 and Example 2, each tin plating solution adjustment procedure, the presence or absence of sludge generation, was simultaneously published in Table 2 to facilitate the contrast of the solder wettability.

TABLE 2

Example 2 Comparative Example 2    Mixed order Solvent: Ion Exchange Water Solvent: Ion Exchange Water ① Sodium Gluconate ① Sodium Gluconate ② Sodium Hydroxide ② Methane sulfonic acid ③ Methane sulfonic acid ③ Methane sulfonic acid tin ④ Methane sulfonic acid tin ④ Sodium Hydroxide ⑤ sodium hydroxide ⑤ Ascorbic acid ⑥ Ascorbic acid ⑥ Lauryl dimethylamino acetic acid betaine ⑦ Lauryl dimethylamino acetic acid betaine   Composition of Tin Plating Solution Methane sulfonic acid tin (tin equivalent): 20 g / L Sodium hydroxide: 31 g / L (Example 2), 46 g / L (Comparative Example 2) Sodium Gluconate: 150g / L Methane sulfonic acid: 68 g / L (Example 2), 135 g / L (Comparative Example 2) Ascorbic acid: 3 g / L Lauryldimethylaminoacetic acid betaine: 1g / L pH: 6.0 Sludge Occurrence Status No sludge after 365 days Sludge after 1 day SEM observation No precipitation and uniform surface Surface with abnormal precipitation Solder Wetability Rating 2 seconds or less More than 3 seconds

Solder Wetting Evaluation: Solder Paste Equilibrium (Quick Heating Mode)

Comparative Example 3

Comparative Example 3 was subjected to the same ⅴ step ~ ⅴ step as in Comparative Example 1, sequentially mixed with sodium gluconate as a chelating agent and methane sulfonic acid with an acidic pH adjuster in ion-exchanged water to prepare a strongly acidic pre-mixture of pH 1 or less, Tin methane sulfonic acid tin was added to tin salt, sodium hydroxide as alkaline pH adjuster, ascorbic acid as antioxidant, and lauryl dimethyl amino acetate betaine as brightener in this order, and the tin plating liquid of the following composition was adjusted.

(Tin plating solution composition)

Methane sulfonic acid tin (tin equivalent): 20 g / L

Sodium Hydroxide: 50g / L

Sodium Gluconate: 150g / L

Methane sulfonic acid: 135 g / L

Ascorbic acid: 3 g / L

Lauryl Dimethyl Amino Betaine: 1g / L

pH: 8.0

(Long-term preservation evaluation of tin plating solution)

The tin plating liquid was stored in an atmospheric atmosphere at room temperature. As a result, sludge was already generated at the time of bathing.

(Observation of tin plating layer)

As a result of observing the surface state using the SEM as in Example 1, it was found that abnormal precipitation appeared on the tin-plated surface as in the case of Comparative Example 1, and that no uniform surface coating was formed. This observation image is omitted because it is the same as in Comparative Example 1. In addition, the tin plating layer observed here is formed using the tin plating liquid in which the sludge generate | occur | produced.

(Solder wettability evaluation)

As in Example 1, as a result of evaluating the characteristics before and after the pressure cooker test, zero cross time was required for 3 seconds or more in order to exhibit good solder wettability.

In order to prepare the above Comparative Example 3 and Example 3, each tin plating solution adjustment procedure, the presence or absence of sludge generation, was simultaneously published in Table 3 to facilitate the contrast of the solder wettability.

TABLE 3

Example 3 Comparative Example 3    Mixed order Solvent: Ion Exchange Water Solvent: Ion Exchange Water ① Sodium Gluconate ① Sodium Gluconate ② Sodium Hydroxide ② Methane sulfonic acid ③ Methane sulfonic acid ③ Methane sulfonic acid tin ④ Methane sulfonic acid tin ④ Sodium Hydroxide ⑤ sodium hydroxide ⑤ Ascorbic acid ⑥ Ascorbic acid ⑥ Lauryl dimethylamino acetic acid betaine ⑦ Lauryl dimethylamino acetic acid betaine    Composition of Tin Plating Solution Methane sulfonic acid tin (tin equivalent): 20 g / L Sodium hydroxide: 35 g / L (Example 3), 50 g / L (Comparative Example 3) Sodium Gluconate: 150g / L Methane sulfonic acid: 68 g / L (Example 3), 135 g / L (Comparative Example 3) Ascorbic acid: 3 g / L Lauryldimethylaminoacetic acid betaine: 1g / L pH: 8.0 Sludge Occurrence Status No sludge after 365 days Sludge Occurs When Drying SEM observation No precipitation and uniform surface Surface with abnormal precipitation Solder Wetability Rating 2 seconds or less More than 3 seconds

Solder Wetting Evaluation: Solder Paste Equilibrium (Quick Heating Mode)

[Comparative Example 4]

In Comparative Example 4, the tin plating solution of the following composition was adjusted through the same ⅰ step to ⅴ step as in Comparative Example 1. The other is citric acid instead of sodium gluconate as the chelating agent. That is, citric acid as a chelating agent and methane sulfonic acid with an acidic pH adjuster are sequentially mixed in ion-exchanged water to prepare a strongly acidic premixture having a pH of 1 or less, and tin salt as methane sulfonic acid tin, sodium hydroxide as an alkaline pH adjuster, Ascorbic acid as an antioxidant and lauryl dimethyl amino acetate betaine were added in order, and the tin plating liquid of the following composition was adjusted.

(Tin plating solution composition)

Methane sulfonic acid tin (tin equivalent): 20 g / L

Sodium Hydroxide: 46g / L

Citric Acid: 150g / L

Methane sulfonic acid: 135 g / L

Ascorbic acid: 3 g / L

Lauryl Dimethyl Amino Betaine: 1g / L

pH: 6.0

(Long-term preservation evaluation of tin plating solution)

The tin plating liquid was stored in an atmospheric atmosphere at room temperature. As a result, sludge was already generated at the time of bathing.

(Appearance of tin plating layer)

The surface state was observed using SEM as in Example 1. And the surface of this tin plating layer was observed with SEM (scanning electron microscope), and the observed image is shown in FIG. It will be clear in comparison with Example 4, but it was found that abnormal precipitation was seen on the tin-plated surface, and uniform surface coating was not formed. In addition, the tin plating layer observed here is formed using the tin plating liquid in which the sludge generate | occur | produced.

(Solder wettability evaluation)

As in Example 1, as a result of evaluating the characteristics before and after the pressure cooker test, zero cross time was required for 3 seconds or more in order to exhibit good solder wettability.

In order to prepare the above Comparative Example 4 and Example 4, it was simultaneously listed in Table 4 to facilitate the tin plating solution adjustment procedure, the presence of sludge generation, the contrast of the solder wettability.

TABLE 4

Example 4 Comparative Example 4    Mixed order Solvent: Ion Exchange Water Solvent: Ion Exchange Water ① Citric acid ① Citric acid ② Sodium Hydroxide ② Methane sulfonic acid ③ Methane sulfonic acid ③ Methane sulfonic acid tin ④ Methane sulfonic acid tin ④ Sodium Hydroxide ⑤ Ascorbic acid ⑤ Ascorbic acid ⑥ Lauryl dimethylamino acetic acid betaine ⑥ Lauryl dimethylamino acetic acid betaine    Composition of Tin Plating Solution Methane sulfonic acid tin (tin equivalent): 20 g / L Sodium hydroxide: 31 g / L (Example 4), 46 g / L (Comparative Example 4) Citric Acid: 150g / L Methane sulfonic acid: 68 g / L (Example 4), 135 g / L (Comparative Example 4) Ascorbic acid: 3 g / L Lauryldimethylaminoacetic acid betaine: 1g / L pH: 6.0 Sludge Occurrence Status No sludge after 365 days Sludge Occurs When Drying SEM observation No precipitation and uniform surface Surface with abnormal precipitation Solder Wetability Rating 2 seconds or less More than 3 seconds

Solder Wetting Evaluation: Solder Paste Equilibrium (Quick Heating Mode)

[Comparative Example 5]

In Comparative Example 5, the tin plating solution of the following composition was adjusted through the same ⅰ step to ⅴ step as in Comparative Example 1. The other is to use polyoxy ethylene lauryl ether instead of lauryl dimethyl amino beta acetate as a brightener. That is, a strong acid premixed solution having a pH of 1 or less is prepared by sequentially mixing sodium gluconate as a chelating agent and methane sulfonic acid with an acidic pH adjuster in ion-exchanged water, and tin hydroxide as a methane sulfonic acid tin and an alkaline pH adjuster. Ascorbic acid as sodium and antioxidant, polyoxyethylene lauryl ether were added in order, and the tin plating liquid of the following composition was adjusted.

(Tin plating solution composition)

Methane sulfonic acid tin (tin equivalent): 14 g / L

Sodium Hydroxide: 42g / L

Sodium Gluconate: 120g / L

Methane sulfonic acid: 135 g / L

Ascorbic acid: 3 g / L

Polyoxyethylene lauryl ether: 1 g / L

pH: 4.0

(Long-term preservation evaluation of tin plating solution)

The tin plating liquid was stored in an atmospheric atmosphere at room temperature. As a result, two days after bathing, the sludge showed.

(Observation of tin plating layer)

As a result of observing the surface state using the SEM as in Example 1, it was found that abnormal precipitation appeared on the tin-plated surface as in the case of Comparative Example 1, and that a uniform surface coating was not formed. Since this observation image is the same as in Comparative Example 1, the publication is omitted. In addition, the tin plating layer observed here is formed using the tin plating liquid in which the sludge generate | occur | produced.

(Solder wettability evaluation)

As a result of evaluating the characteristics before and after the pressure cooker test as in Example 1, zero cross time was required for 3 seconds or more in order to exhibit good solder wettability.

In order to prepare the above Comparative Example 5 and Example 5, each tin plating solution adjustment procedure, the presence or absence of sludge generation, was simultaneously published in Table 5 to facilitate the contrast of the solder wettability.

TABLE 5

Example 5 Comparative Example 5    Mixed order Solvent: Ion Exchange Water Solvent: Ion Exchange Water ① Sodium Gluconate ① Sodium Gluconate ② Sodium Hydroxide ② Methane sulfonic acid ③ Methane sulfonic acid ③ Methane sulfonic acid tin ④ Methane sulfonic acid tin ④ Sodium Hydroxide ⑤ sodium hydroxide ⑤ Ascorbic acid ⑥ Ascorbic acid ⑥ polyoxyethylene lauryl ether ⑦ polyoxyethylene lauryl ether    Composition of Tin Plating Solution Methane sulfonic acid tin (in terms of tin): 14 g / L (Example 5), 20 g / L (Comparative Example 5) Sodium Hydroxide: 42g / L Sodium Gluconate: 120g / L Methane sulfonic acid: 135 g / L Ascorbic acid: 3 g / L Polyoxyethylene lauryl ether: 1 g / L pH: 4.0 Sludge Occurrence Status No sludge after 365 days Sludge after 2 days SEM observation No precipitation and uniform surface Surface with abnormal precipitation Solder Wetability Rating 2 seconds or less More than 3 seconds

Solder Wetting Evaluation: Solder Paste Equilibrium (Quick Heating Mode)

Comparative Example 6

In Comparative Example 6, the tin plating liquid of the following composition was adjusted through the same ⅰ step to 1 step as in Comparative Example 1. The other is the use of tin sulfate instead of methane sulfonic acid tin as the tin salt and polyoxyethylene lauryl ether instead of lauryl dimethyl amino beta acetate as the brightener. That is, a strong acid premixture having a pH of 1 or less is prepared by sequentially mixing sodium gluconate as a chelating agent and methane sulfonic acid with an acidic pH adjuster, and tin sulfate as a tin salt, sodium hydroxide as an alkaline pH adjuster, and the like. Ascorbic acid as an antioxidant and polyoxyethylene lauryl ether as a brightener were added in order, and the tin plating liquid of the following composition was adjusted.

(Tin plating solution composition)

Tin sulfate (in terms of tin): 14 g / L

Sodium Hydroxide: 42g / L

Sodium Gluconate: 120g / L

Methane sulfonic acid: 135 g / L

Ascorbic acid: 3 g / L

Polyoxyethylene lauryl ether: 1 g / L

pH 4.0

(Long-term preservation evaluation of tin plating solution)

The tin plating liquid was stored in an atmospheric atmosphere at room temperature. As a result, two days after bathing, the sludge showed.

(Appearance of tin plating layer)

The surface state was observed using SEM as in Example 1. And the surface of this tin plating layer was observed with SEM (scanning electron microscope), and the observed image is shown in FIG. It will be clear in contrast to Example 6, but it was found that abnormal precipitation appeared on the tin-plated surface and that no uniform surface coating was formed. In addition, the tin plating layer observed here is formed using the tin plating liquid in which the sludge generate | occur | produced.

(Solder wettability evaluation)

As a result of evaluating the characteristics before and after the pressure cooker test as in Example 1, zero cross time was required for 3 seconds or more in order to exhibit good solder wettability.

In order to prepare the above Comparative Example 6 and Example 6, each tin plating solution adjustment procedure, the presence or absence of sludge generation, was simultaneously published in Table 6 to facilitate the contrast of the solder wettability.

TABLE 6

Example 6 Comparative Example 6    Mixed order Solvent: Ion Exchange Water Solvent: Ion Exchange Water ① Sodium Gluconate ① Sodium Gluconate ② Sodium Hydroxide ② Methane sulfonic acid ③ Methane sulfonic acid ③Sulfate of sulfuric acid ④ Tin sulfate ④ Sodium Hydroxide ⑤ sodium hydroxide ⑤ Ascorbic acid ⑥ Ascorbic acid ⑥ polyoxyethylene lauryl ether ⑦ polyoxyethylene lauryl ether    Composition of Tin Plating Solution Tin sulfate (in terms of tin): 14 g / L Sodium Hydroxide: 42g / L Sodium Gluconate: 120g / L Methane sulfonic acid: 135 g / L Ascorbic acid: 3 g / L Polyoxyethylene lauryl ether: 1 g / L pH: 4.0 Sludge Occurrence Status No sludge after 365 days Sludge after 2 days SEM observation No precipitation and uniform surface Surface with abnormal precipitation Solder Wetability Rating 2 seconds or less More than 3 seconds

Solder Wetting Evaluation: Solder Paste Equilibrium (Quick Heating Mode)

Comparative Example 7

In Comparative Example 7, the tin plating solution having the following composition was adjusted through the same ⅰ step to ⅴ step as in Comparative Example 1. Others use catechol instead of ascorbic acid as antioxidant and polyoxyethylene lauryl ether instead of lauryl dimethyl amino beta acetate as a brightener. That is, a strong acid premixed solution having a pH of 1 or less is prepared by sequentially mixing sodium gluconate as a chelating agent and methane sulfonic acid with an acidic pH adjuster in ion-exchanged water, and tin hydroxide as a methane sulfonic acid tin and an alkaline pH adjuster. Sodium and catechol as an antioxidant and polyoxyethylene lauryl ether as a brightening agent were added in order, and the tin plating liquid of the following composition was adjusted.

(Tin plating solution composition)

Methane sulfonic acid tin (tin equivalent): 14 g / L

Sodium Hydroxide: 42g / L

Sodium Gluconate: 120g / L

Methane sulfonic acid: 135 g / L

Catechol: 3 g / L

Polyoxyethylene lauryl ether: 1 g / L

pH: 4.0

(Long-term preservation evaluation of tin plating solution)

The tin plating liquid was stored in an atmospheric atmosphere at room temperature. As a result, two days after the bathing, the sludge appeared.

(Observation of tin plating layer)

As a result of observing the surface state using the SEM as in Example 1, it was found that abnormal precipitation was observed on the tin-plated surface as in Comparative Example 1, and that no uniform surface coating was formed. Since this observation image is the same as in Comparative Example 1, the publication is omitted. In addition, the tin plating layer observed here is formed using the tin plating liquid in which the sludge generate | occur | produced.

(Solder wettability evaluation)

As a result of evaluating the characteristics before and after the pressure cooker test as in Example 1, zero cross time was required for 3 seconds or more in order to exhibit good solder wettability.

In order to prepare the above Comparative Example 7 and Example 7, the tin plating solution adjustment procedure, the presence or absence of sludge generation, and simultaneously published in Table 7 so that the contrast of the solder wettability.

TABLE 7

Example 7 Comparative Example 7    Mixed order Solvent: Ion Exchange Water Solvent: Ion Exchange Water ① Sodium Gluconate ① Sodium Gluconate ② Sodium Hydroxide ② Methane sulfonic acid ③ Methane sulfonic acid ③ Methane sulfonic acid tin ④ Methane sulfonic acid tin ④ Sodium Hydroxide ⑤ sodium hydroxide ⑤Catechol ⑥ Catechol ⑥ polyoxyethylene lauryl ether ⑦ polyoxyethylene lauryl ether    Composition of Tin Plating Solution Methane sulfonic acid tin (tin equivalent): 14 g / L Sodium Hydroxide: 42g / L Sodium Gluconate: 120g / L Methane sulfonic acid: 135 g / L Catechol: 3g / L Polyoxyethylene lauryl ether: 1 g / L pH: 4.0 Sludge Occurrence Status No sludge after 365 days Sludge after 2 days SEM observation No precipitation and uniform surface Surface with abnormal precipitation Solder Wetability Rating 2 seconds or less More than 3 seconds

Solder Wetting Evaluation: Solder Paste Equilibrium (Quick Heating Mode)

Comparative Example 8

In Comparative Example 8, the tin plating liquid of the following composition was adjusted through the same ⅰ step to ⅴ step as in Comparative Example 1. The other is adding ascorbic acid as an antioxidant and sodium sulfate as a conductive salt. That is, a strong acid premixed solution having a pH of 1 or less is prepared by sequentially mixing sodium gluconate as a chelating agent and methane sulfonic acid with an acidic pH adjuster in ion-exchanged water, and tin hydroxide as a methane sulfonic acid tin and an alkaline pH adjuster. Ascorbic acid as a sodium and an antioxidant, sodium sulfate which is a conductive salt, and lauryl dimethylamino acetic acid betaine as a brightener were added in order, and the tin plating liquid of the following composition was adjusted.

(Tin plating solution composition)

Methane sulfonic acid tin (tin equivalent): 20 g / L

Sodium Hydroxide: 46g / L

Sodium Gluconate: 150g / L

Methane sulfonic acid: 135 g / L

Ascorbic acid: 3 g / L

Sodium Sulfate: 70g / L

Lauryl Dimethyl Amino Betaine: 1g / L

pH: 6.0

(Long-term preservation evaluation of tin plating solution)

The tin plating liquid was stored in an atmospheric atmosphere at room temperature. As a result, when one day passed after bathing, the sludge generate | occur | produced.

(Observation of tin plating layer)

As a result of observing the surface state using the SEM as in Example 1, it was found that abnormal precipitation was observed on the tin-plated surface as in Comparative Example 1, and uniform surface coating was not formed. Since this observation image is the same as in Comparative Example 1, the publication is omitted. In addition, the tin plating layer observed here is formed using the tin plating liquid in which the sludge generate | occur | produced.

(Solder wettability evaluation)

As a result of evaluating the characteristics before and after the pressure cooker test as in Example 1, zero cross time was required for 3 seconds or more in order to exhibit good solder wettability.

In order to prepare the above Comparative Example 8 and Example 8, each tin plating solution adjustment procedure, the presence or absence of sludge generation, was simultaneously published in Table 8 to facilitate the contrast of the solder wettability.

TABLE 8

Example 8 Comparative Example 8    Mixed order Solvent: Ion Exchange Water Solvent: Ion Exchange Water ① Sodium Gluconate ① Sodium Gluconate ② Sodium Hydroxide ② Methane sulfonic acid ③ Methane sulfonic acid ③ Methane sulfonic acid tin ④ Methane sulfonic acid tin ④ Sodium Hydroxide ⑤ sodium hydroxide ⑤ Ascorbic acid + sodium sulfate ⑥ Ascorbic acid + sodium sulfate ⑥ Lauryl dimethylamino acetic acid betaine ⑦ Lauryl dimethylamino acetic acid betaine    Composition of Tin Plating Solution Methane sulfonic acid tin (tin equivalent): 20 g / L Sodium hydroxide: 31 g / L (Example 8), 46 g / L (Comparative Example 8) Sodium Gluconate: 150g / L Methane sulfonic acid: 68 g / L (Example 8), 135 g / L (Comparative Example 8) Ascorbic acid: 3 g / L Sodium Sulfate: 70g / L Lauryldimethylaminoacetic acid betaine: 1g / L pH: 6.0 Sludge Occurrence Status No sludge after 365 days Sludge after 2 days SEM observation No precipitation and uniform surface Surface with abnormal precipitation Solder Wetability Rating 2 seconds or less More than 3 seconds

Solder Wetting Evaluation: Solder Paste Equilibrium (Quick Heating Mode)

Comparative Example 9

The comparative example 9 adjusted the tin plating liquid of the following composition completely different from the comparative example 1-the comparative example 8 mentioned above. Here, the mixing order of the following components is not a problem, and each component is dissolved in water as a solvent so as to have a predetermined concentration, and the pH is adjusted with ammonia water.

(Basic composition of tin plating solution)

Sulfur phase tin (in terms of tin): 25 g / L

Hydrogen Citrate Ammonium: 95g / L

Alkyl amine type surfactant: 0.1 g / L

Ammonium Sulfate: 13g / L

pH (adjusted with ammonia water): 7.0

(Long-term preservation evaluation of tin plating solution)

The tin plating liquid was stored in an atmospheric atmosphere at room temperature. As a result, when one day passed after bathing, the sludge generate | occur | produced.

Comparative Example 10

Comparative Example 10 adjusted the tin plating liquid of a composition completely different from Comparative Examples 1 to 8 described above. Here, the mixing order of the following components is not a problem, and each component is dissolved in water as a solvent to a predetermined concentration, and then pH is adjusted with sodium hydroxide.

(Basic composition of tin plating solution)

Sulfamic acid first tin (in tin): 50 g / L

Malic acid: 450 g / L

Alkyl amine type surfactant: 0.1 g / L

pH (adjusted with sodium hydroxide): 6.0

(Long-term preservation evaluation of tin plating solution)

The tin plating liquid was stored in an atmospheric atmosphere at room temperature. As a result, after 5 hours of bathing, the generation of sludge was observed.

<Contrast of Example and Comparative Example>

Contrast between Example 1 and Comparative Example 1: As shown in Table 1, the tin plating solutions of Example 1 and Comparative Example 1 are identical in terms of composition and pH. The other is the mixing order of the components. That is, in Example 1, sodium gluconate as a chelating agent, sodium hydroxide as an alkaline pH adjusting agent, and methane sulfonic acid as an acidic pH adjusting agent were sequentially added to ion-exchanged water to make the pH of the solution 12, and tin methane sulfonic acid tin was added. In addition, a method of reliably generating tin chelate complexes is employed. Then, sodium hydroxide as an unadjusted alkaline pH adjuster, ascorbic acid as an antioxidant, and lauryl dimethyl amino betaine as a brightener are added in this order.

On the other hand, in Comparative Example 1, sodium gluconate as a chelating agent and methane sulfonic acid were added to the ion-exchanged water in order, and the pH of the solution was made to be a strongly acidic solution of 1 or less. Add. In the conventional tin plating solution manufacturing method, a method of adding tin salt in an acidic region has been adopted. Then, sodium hydroxide as an alkaline pH adjuster, ascorbic acid as an antioxidant, and lauryl dimethyl amino acetate betaine are added in order to approach the pH of the tin plating solution to the neutral region.

As such, Example 1 and Comparative Example 1 only differ in the mixing order of the components, but the nature and state of the solution are completely different. Therefore, even if the amount of the constituents is the same, it can be said that the present method of the tin component contained in the tin plating solution is completely different. The supporting contents are as follows. In the case of Example 1, even if it is stored in air | atmosphere atmosphere of room temperature-40 degreeC, and 365 days pass, the generation of sludge is not seen at all.

In the case of the tin plating solution of Example 1, even when 365 days have elapsed, even when the tin plating layer of the test sample subjected to the plating test is observed by SEM, the precipitated particles appear to be planarly covered on the entire surface, and an extremely good surface is obtained. And below, this is only called "uniform surface."). On the other hand, in the case of the tin plating solution of Comparative Example 1, sludge generation is recognized, and the surface of the tin plating layer is found to be deposited on the entire surface of the tin plating plane and deposited particles are further deposited thereon, and thus the surface is not uniform. In the following, such a state is called "abnormal precipitation.").

In addition, regarding the solder wettability, the tin plating solution of Example 1 can form a tin plating layer having good solder wettability even after 365 days have elapsed. In contrast, the tin plating liquid of Comparative Example 1 is inferior in solder wettability due to the generation of sludge.

Comparison of Example 2 and Comparative Example 2: The relationship between Example 2 and Comparative Example 2 is also basically the same as that of Example 1 and Comparative Example 1. Fundamentally, the mixing order of the components is different. However, since the addition amount of methane sulfonic acid which is the acidic pH adjuster contained in Example 2 and Comparative Example 2 differs, the addition amount of the alkaline pH adjuster which makes pH of a final tin plating liquid also 6.0 differs.

That is, the component of the tin plating liquid of Example 2 is the same as that of Example 1, and a mixing order is the same. In addition, the component of the tin plating liquid of the comparative example 2 is the same as that of the comparative example 1, and the mixing order is also the same. However, in Example 2, Example 1, Comparative Example 2, and Comparative Example 1, the amount of each component is different as shown in Table 2.

Thus, although Example 2 and Comparative Example 2 only differ in the mixing order of components, the nature and state of the solution are completely different. Therefore, as in the case of Example 1, even if the components are the same, it can be said that the present method of the tin component contained in the tin plating solution is completely different. The supporting contents are as follows. In the case of Example 2, even if it stored in the air atmosphere of room temperature-40 degreeC, and 365 days passed, the generation of sludge was not seen at all. On the other hand, in the case of the comparative example 2, generation | occurrence | production of sludge was confirmed after only 1 day passed. In the case of Example 2, even if the pH of the solution was arbitrarily changed between 4 and 10 using sodium hydroxide, the generation of sludge was not observed at all even after 365 days elapsed after storing in an air atmosphere at room temperature to 40 ° C.

And in the tin plating liquid of Example 2, as a result of observing the tin plating layer of the test sample which carried out plating test 365 days later, extremely favorable uniform surface was obtained. On the other hand, in the tin plating liquid of the comparative example 2, abnormal precipitation was seen in the surface of a tin plating layer by the generation of sludge, and it was confirmed that it is a definite defective state.

In addition, regarding the solder wettability, in the tin plating solution of Example 2, the tin plating layer having good solder wettability can be formed even after 365 days have elapsed. On the other hand, in the tin plating liquid of the comparative example 2, solder wettability is inferior by the generation of sludge.

Comparison between Example 3 and Comparative Example 3: The relationship between Example 3 and Comparative Example 3 is basically the same as that of Example 1 and Comparative Example 1. In essence, the mixing order of the components is different. However, since the addition amount of methane sulfonic acid which is an acidic pH adjuster differs in Example 3 and Comparative Example 3, the addition amount of an alkaline pH adjuster also differs so that pH of a final tin plating liquid may be 8.0.

That is, the component of the tin plating liquid of Example 3 is the same as that of Example 1, and a mixing procedure is the same. In addition, the component of the tin plating liquid of the comparative example 3 is the same as that of the comparative example 1, and the mixing order is also the same. However, in Example 3, Example 1, Comparative Example 3, and Comparative Example 1, the amount of each component is different as shown in Table 3.

In this way, Example 3 and Comparative Example 3 only differ in the mixing order of the components, but the nature and state of the solution are completely different. Therefore, as in the case of Example 1, even if the constituents are the same, the present method of the tin component contained in the tin plating solution is completely different. This support is described below. In the case of Example 3, even if it stored in air | atmosphere of room temperature-40 degreeC, and 365 days passed, the generation of sludge will not be seen at all. On the other hand, in the case of the comparative example 3, generation | occurrence | production of sludge was confirmed already at the time of bathing.

And in the case of the tin plating liquid of Example 3, when the tin plating layer of the test sample which performed the plating test after lapse of 365 days was observed by SEM, extremely favorable uniform surface was obtained. On the other hand, in the case of the tin plating liquid of the comparative example 3, abnormal precipitation was seen in the surface of a tin plating layer by the generation of sludge, and it was confirmed that it is in the obvious defective state.

Also, regarding the solder wettability, in the case of the tin plating solution of Example 3, the tin plating layer having good solder wettability can be formed after 365 days. On the other hand, in the case of the tin plating liquid of the comparative example 3, solder wettability is inferior by the generation of sludge.

Comparison of Example 4 and Comparative Example 4: Example 4 used citric acid instead of sodium gluconate, the chelating agent of Example 1. That is, in Example 4, citric acid, sodium hydroxide as an alkaline pH adjuster, and methane sulfonic acid as an acidic pH adjuster are added to ion-exchanged water in order to pH 6.0, and tin is added to tin methane sulfonic acid tin as a tin salt. The method of generating a chelate complex reliably is adopted. Then, sodium hydroxide as a fine adjustment alkaline pH adjuster, ascorbic acid as an antioxidant, lauryl dimethyl amino acetate betaine as a brightening agent were added in order, and the final tin plating liquid pH was 6.0.

On the other hand, in Comparative Example 4, citric acid as a chelating agent and methane sulfonic acid as an acidic pH adjuster are sequentially added to ion-exchanged water to make the pH of the solution strongly acidic with 1 or less, and tin methane sulfonic acid tin is added thereto. In the conventional tin plating solution manufacturing method, a method of adding tin salt in an acidic region has been adopted. Then, in order to bring the pH of the tin plating solution closer to the neutral region, sodium hydroxide as an alkaline pH adjuster, ascorbic acid as an antioxidant, and lauryl dimethyl amino acetate betaine as a brightening agent are added in this order to adjust the pH of the final tin plating solution. 6.0 was set. However, since the addition amount of methane sulfonic acid which is an acidic pH adjuster contained in Example 4 and Comparative Example 4 differs, the addition amount of an alkaline pH adjuster also changes so that pH of a final tin plating liquid may be 6.0.

In Example 4 and Comparative Example 4, only the mixing order of components is different, but the nature and state of the solution are completely different. Therefore, as in the case of Example 1, even if the components are the same, it can be said that the method of the presence of the tin component contained in the tin plating solution is completely different. The supporting contents are as follows. In the case of Example 4, even if it stored in air | atmosphere atmosphere of room temperature-40 degreeC, and 365 passed, the generation of sludge will not be seen at all. On the other hand, in the case of the comparative example 4, generation | occurrence | production of the sludge at the time of bathing was confirmed already.

And in the case of the tin plating liquid of Example 4, when the tin plating layer of the test sample which performed the plating test after 365 days passed was observed by SEM, the extremely favorable uniform surface was obtained. On the other hand, in the tin plating liquid of the comparative example 4, sludge generate | occur | produced and showed abnormal precipitation on the surface of a tin plating layer, and it was confirmed that it is a clear defective state.

In addition, regarding the solder wettability, the tin plating solution of Example 4 can form a tin plating layer having good soldering properties even after 365 days have elapsed. On the other hand, in the tin plating liquid of the comparative example 4, sludge generate | occur | produces and solder wettability is inferior.

Contrast of Example 5 to Example 5: In Example 5, polyoxyethylene lauryl ether was used in place of the lauryl dimethyl amino beta acetate, which is the brightener of Example 1. That is, in Example 5, sodium gluconate as a chelating agent, sodium hydroxide as an alkaline pH adjuster, and methane sulfonic acid as an acidic pH adjuster were added to ion-exchanged water in order to make the pH of the solution 12, to which methane sulfonic acid as tin salt was added. The method of generating tin chelate complexes by adding tin is adopted. Then, ascorbic acid as an antioxidant and polyoxyethylene lauryl ether as a brightener were added in order, and the pH of the final tin plating liquid was set to 4.0.

On the other hand, in Comparative Example 5, sodium gluconate as a chelating agent and methane sulfonic acid as an acidic pH adjuster are added to ion-exchanged water in order to make the pH of the solution strong acidity of 1 or less, and tin methane sulfonic acid tin is added thereto. It was. Then, in order to bring the pH of the tin plating solution closer to the neutral region, sodium hydroxide as an alkaline pH adjuster, ascorbic acid as an antioxidant, and polyoxyethylene lauryl ether as a brightener are added in this order, and the pH of the final tin plating solution is added. Was set to 4.0.

Example 5 and Comparative Example 5 only differ in the mixing order of the components, but the nature and state of the solution are completely different. Therefore, as in the case of Example 1, even if the components are the same, the method of presenting the tin component contained in the tin plating solution is completely different. The supporting contents are as follows. In the case of Example 5, even if it is stored in air | atmosphere atmosphere of room temperature-40 degreeC, and 365 days pass, the generation of sludge is not seen at all. On the other hand, in the case of the comparative example 5, generation | occurrence | production of sludge was confirmed after only 2 days passed from dry bath.

And in the case of the tin plating liquid of Example 5, as a result of observing the tin plating layer of the test sample which performed the plating test after 365 days passed by an SEM, extremely favorable uniform surface was obtained. On the other hand, in the case of the tin plating liquid of the comparative example 5, sludge generate | occur | produced and abnormal precipitation was seen on the surface of a tin plating layer, and it was confirmed that it is a clear defective state.

Also, regarding the solder wettability, in the case of the tin plating solution of the fifth embodiment, it is possible to form a tin plating layer having good solder wettability even after 365 days have elapsed. On the other hand, in the tin plating liquid of the comparative example 5, solder wettability is inferior by the generation of sludge.

Contrast to Example 6 compared to Example 6: In Example 6, tin sulfate was used instead of the tin salt of methane sulfonic acid tin of Example 1, and polyoxyethylene lauryl ether was used instead of the lauryl dimethyl amino beta acetate, which is a polishing agent. . That is, in Example 6, sodium gluconate as a chelating agent, sodium hydroxide as an alkaline pH adjuster, and methane sulfonic acid as an acidic pH adjuster were added to ion-exchanged water in order to make the pH of the solution 12, and tin sulfate as a tin salt was added thereto. In addition, a method of reliably generating tin chelate complexes is employed. Then, ascorbic acid as an antioxidant and polyoxyethylene lauryl ether as a brightener were added in order, and the pH of the final tin plating liquid was set to 4.0.

On the other hand, in Comparative Example 6, sodium gluconate as a chelating agent and methane sulfonic acid as an acidic pH adjuster are sequentially added to ion-exchanged water to make the pH of the solution strongly acidic with 1 or less, and tin sulfate as a tin salt is added thereto. Then, in order to bring the pH of the tin plating solution closer to the neutral region, sodium hydroxide as an alkaline pH adjuster, ascorbic acid as an antioxidant, and polyoxyethylene lauryl ether as a brightener are added in this order, and the final pH of the tin plating solution is adjusted. 4.0 was set.

In Example 6 and Comparative Example 6, only the mixing order of the components is different, but the nature and state of the solution are completely different. Therefore, as in the case of Example 1, even if the components are the same, the present method of the tin component contained in the tin plating solution can be said to be completely different. The supporting contents are as follows. In the case of Example 6, even if stored in the air atmosphere of room temperature ~ 40 ℃ and elapsed 365 days, the generation of sludge is not seen at all. On the other hand, in the case of the comparative example 6, generation | occurrence | production of sludge was confirmed after only 2 days passed from dry bath.

And in the case of the tin plating liquid of Example 6, 365 days passed and the tin plating layer of the test sample which performed the plating test was observed by SEM, and the extremely favorable uniform surface was obtained. On the other hand, in the case of the tin plating liquid of the comparative example 6, abnormal precipitation was seen on the surface of a tin plating layer by the generation of sludge, and it was confirmed that it is a clear defective state.

In addition, regarding the solder wettability, in the case of the tin plating solution of Example 6, the tin plating layer having good solder wettability can be formed even after 365 days have elapsed. On the other hand, in the tin plating liquid of the comparative example 6, sludge generate | occur | produces and solder wettability is inferior.

Comparison of Example 7 and Comparative Example 7: In Example 7, catechol was used instead of ascorbic acid, which is the antioxidant of Example 1, and polyoxyethylene lauryl ether was used instead of lauryl dimethyl amino beta acetate, which is a brightening agent. . That is, in Example 7, the pH of the solution was adjusted to 12 by adding sodium gluconate as a chelating agent, sodium hydroxide as an alkaline pH adjuster, and methane sulfonic acid as an acidic pH adjuster to ion-exchanged water, and methane sulfonic acid as tin salt. The method of producing tin chelate complexes by adding tin is adopted. Then, catechol as an antioxidant and polyoxyethylene lauryl ether as a brightener were added in that order, and the pH of the final tin plating liquid was 4.0.

On the other hand, in comparison, 7 is added to the ion-exchanged water, sodium gluconate, a chelating agent, and methane sulfonic acid, an acidic pH adjuster, in order to make the pH of the solution strongly acidic with 1 or less, and tin methane sulfonic acid tin is added thereto. It was. Then, in order to bring the pH of the tin plating solution closer to the neutral region, sodium hydroxide as an alkaline pH adjuster, catechol as an antioxidant, and polyoxyethylene lauryl ether as a brightener are added in order to adjust the pH of the final tin plating solution. 4.0 was set.

In Example 7 and Comparative Example 7, only the mixing order of the components is different, but the nature and state of the solution are completely different. Therefore, as in the case of Example 1, even if the components are the same, the present method of the tin component contained in the tin plating solution can be said to be completely different. The supporting contents are as follows. In the case of Example 7, the sludge was not seen at all even after 365 days elapsed after being stored in an air atmosphere at room temperature to 40 ° C. On the other hand, in the case of the comparative example 7, sludge generation was confirmed after only 2 days passed from dry bath.

And in the tin plating liquid of Example 7, 365 days passed, when the tin plating layer of the test sample which performed the plating test was observed by SEM, the extremely favorable uniform surface was obtained. On the other hand, in the case of the tin plating liquid of the comparative example 7, it was confirmed that abnormal precipitation was seen in the surface of a tin plating layer by the generation of sludge, and it was confirmed that it is a definite defective state.

In addition, regarding the solder wettability, in the case of the tin plating solution of Example 7, even if 365 days have elapsed, the tin plating layer having good solder wettability can be formed. On the other hand, in the tin plating liquid of the comparative example 7, sludge generate | occur | produces and solder wettability is inferior.

Contrast of Example 8 to Example 8: Example 8 was prepared by adding chelating sodium gluconate, alkaline pH adjusting agent sodium hydroxide, and acidic pH adjusting agent methane sulfonic acid in order to make the pH of the solution 12; A method of reliably generating a tin chelate complex by adding tin salt methane sulfonic acid tin is employed. Then, ascorbic acid as an antioxidant and sodium sulfate as a conductive salt were simultaneously added, and lauryl dimethine amino acetate betaine as a brightening agent was added sequentially, and the final tin plating solution had a pH of 6.0.

On the other hand, in Comparative Example 8, sodium gluconate as a chelating agent and methane sulfonic acid as an acidic pH adjuster were sequentially added to ion-exchanged water to make the pH of the solution strongly acidic with 1 or less, and tin methane sulfonic acid tin was added thereto. It was. As a conventional method for producing a tin plating solution, a method of adding tin salt in an acidic region has been adopted. Then, in order to approach the pH of the tin plating solution to the neutral region, sodium hydroxide as an alkaline pH adjuster, ascorbic acid as an antioxidant and sodium sulfate as a conductive salt are simultaneously added, and lauryl dimethyl amino beta acetate as a polishing agent is added in order. As it was added, the pH of the final tin plating solution was 6.0. However, since the addition amount of methane sulfonic acid which is an acidic pH adjuster contained in Example 8 and Comparative Example 8 differs, the addition amount of an alkaline pH adjuster also changes so that pH of a final tin plating liquid may be 6.0.

Example 8 and Comparative Example 8 merely differ in the mixing order of the components, but the nature and state of the solution are completely different. Therefore, as in the case of Example 1, even if the components are the same, it can be said that the present method of the tin component contained in the tin plating solution is completely different. The supporting contents are as follows. In the case of Example 8, even if it is stored in the air atmosphere of room temperature-40 degreeC, and 365 days pass, the generation of sludge is not seen at all. On the other hand, in the case of the comparative example 8, generation | occurrence | production of sludge was confirmed after only 2 days passed from dry bath.

And in the case of the tin plating liquid of Example 8, as a result of observing the tin plating layer of the test sample which performed the plating test after 365 days passed, the extremely favorable uniform surface was obtained. On the other hand, in the case of the tin plating liquid of the comparative example 8, abnormal precipitation was seen in the surface of a tin plating layer by the generation of sludge, and it was confirmed that it is a definite defective state.

Also, regarding the solder wettability, in the tin plating solution of Example 8, even after 365 days have elapsed, the tin plating layer having good solder wettability can be formed. On the other hand, in the tin plating liquid of the comparative example 8, sludge generate | occur | produces and solder wettability is inferior.

And the opinion about 10 is shown in the comparative example 9 and the comparison. Although there are no examples which can be directly compared with Comparative Example 9 and Comparative Example 10, it is to publish according to the tin plating liquid composition which can be considered, and to compare the solution life until sludge generation with each said Example. As described above, in the tin plating solution of Comparative Example 9, sludge generation can be seen after 1 day from the dry bath. In the tin plating solution of Comparative Example 10, sludge was generated after 5 hours from drying. Moreover, in the tin plating liquid of the comparative example 9 and the comparative example 10 after confirming the generation of sludge, it was not able to confirm that the tin plating film with uniformity was formed. That is, compared with the tin plating liquid according to the present invention described above, it can be readily understood that the tin plating liquid of Comparative Example 9 and Comparative Example 10 is extremely short solution life.

The tin plating solution according to the present invention does not generate sludge even after a period of one year passes, and the solution life after the bath is remarkably long, even when compared with the conventional tin plating solution, and the plating solution management is easy, so the economy is excellent. In addition, the tin plating solution according to the present invention is capable of plating operation in a temperature range of 10 ° C to 40 ° C, and due to proper liquid evaporation, does not cause a significant increase in the amount of wastewater, thereby reducing the load of wastewater treatment, thereby reducing the overall cost. Make it possible.

In addition, the tin plating liquid adjusting method according to the present invention does not require a special apparatus and method, and it is possible to effectively utilize existing equipment only by following a certain adjusting procedure.

Claims (17)

As a tin plating liquid for tin plating by the electrolytic method, Water, pH adjuster and chelating agent are mixed to prepare a mixed solution having a pH value of 6-12, and tin salt is added to the mixed solution so that the tin content is 5 g / L to 30 g / L, and stirred sufficiently to chelate tin The tin plating liquid which formed the complex and does not generate | occur | produce sludge more than 7 days on the conditions of 10 degreeC-40 degreeC of bath temperatures. The tin plating solution according to claim 1, wherein the tin salt is one kind or two or more kinds selected from the first tin salts soluble in water. The method of claim 1, wherein the chelating agent is characterized in that one or two or more selected from gluconic acid, gluconate, citric acid, citrate, pyrophosphate, pyrophosphate to 30g / L ~ 300g / L concentration Tin plating solution. The tin plating solution according to claim 1, wherein the pH adjusting agent is an alkaline pH adjusting agent, and includes one or two or more selected from sodium hydroxide, potassium hydroxide, and ammonia water to have a concentration of 5 g / L to 140 g / L. . According to claim 1, wherein the pH adjuster is an acidic pH adjuster, wherein one or two or more selected from methane sulfonic acid, ethane sulfonic acid, sulfuric acid, isethionic acid is contained so as to have a concentration of 10g / L ~ 300g / L Tin plating solution, characterized in that. The tin plating liquid according to claim 1, further comprising an antioxidant at a concentration of 0.1 g / L to 30 g / L. According to claim 1, wherein the pH adjuster for finely adjusting the pH of the tin plating solution to the acidic side, methane sulfonic acid, sulfuric acid, one or two, A tin plating solution characterized in that the pH is in the range of 4 to 10 by including one or two of the methane sulfonic acid and sulfuric acid. The pH adjusting agent according to claim 1, wherein the pH adjusting agent is for fine-adjusting the pH of the tin plating solution to the alkali side, and is one or two types of sodium hydroxide, potassium hydroxide and aqueous ammonia, The tin plating solution characterized by including pH 1 in the range of 4-10 by containing 1 type or 2 types of the said sodium hydroxide, potassium hydroxide, and ammonia water. The tin plating liquid according to claim 1, further comprising one or two or more selected from sodium sulfate and ammonium sulfate as conductive salts so as to have a concentration of 1 g / L to 150 g / L. The tin plating liquid according to claim 1, further comprising one or two or more selected from nonionic surfactants, cationic surfactants, and amphoteric surfactants so as to have a concentration of 0.1 g / L to 30 g / L as a brightening agent. . The tin plating method using the tin plating liquid as described in any one of Claims 1-10, Electrolyzed on condition of bath temperature 10 degreeC-40 degreeC, The tin plating method characterized by the above-mentioned. A method of adjusting the tin plating liquid of any one of claims 1 to 10, A) Mixing water, pH adjuster and chelating agent to prepare a mixed solution having a pH value of 6-12, B) The tin plating liquid adjustment method characterized by manufacturing a tin plating liquid by adding tin salt to the said mixed solution so that tin content may be 5 g / L-30 g / L concentration, and fully stirring to form a tin chelate complex. The tin plating liquid adjusting method according to claim 12, further comprising a step of adding an antioxidant to the tin plating liquid. The tin plating liquid adjusting method according to claim 12, further comprising a step of fine-adjusting the pH value of the tin plating liquid. The tin plating liquid adjusting method according to claim 12, further comprising a step of adding a conductive salt to the tin plating liquid. The tin plating liquid adjusting method according to claim 12, further comprising a step of adding a polishing agent to the tin plating liquid. A chip component comprising a tin plating layer using the tin plating of any one of claims 1 to 10.

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