JPH0148352B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a plating solution for plating tin metals such as tin plating, lead plating, and tin-lead alloy plating. Conventional technology Tin metal plating, such as tin plating, lead plating, and tin-lead alloy plating, is effective in improving the solderability of terminals of electrical components and printed wiring boards, so it has recently been Demand is increasing with the development of the electronic equipment industry, and along with this, demands for improved performance are also becoming stronger. Conventionally,
For tin plating, sulfuric acid bath or alkaline stannic acid bath is used.
In addition, hofuting baths were commonly used for tin-lead alloy plating, but in recent years, the use of organic sulfonic acid baths and organic carboxylic acid baths has been considered from the perspective of pollution prevention. , some of which have been put into practical use. The general requirements for tin metal plating in the above applications are that the precipitated crystals be fine and uniform in appearance for both bright plating and semi-bright plating, and that the recesses of the part be reliably plated. The solderability of the plating film is excellent, and in the case of alloy plating, the precipitation ratio of tin and lead is consistent with the target value and is uniform. The conventionally proposed or implemented means to solve these problems is to add brighteners, alkanesulfonic acids, alkanolsulfonic acids, surfactants, gluconic acid, gluconolactone, etc. as auxiliaries to the plating solution. (Japanese Patent Publications No. 57-203785, No. 59-67387, Japanese Patent Publications No. 57-2037-
27188, 59-10997, etc.). Although each of these auxiliary agents has its own effects, many of them have advantages and disadvantages, and the addition of surfactants can cause foaming of the plating solution, impairing operability. It has been difficult to achieve a satisfactory plating solution with a combination of these auxiliaries. Problems to be Solved by the Invention The purpose of the present invention is to address the above-mentioned current situation and to provide a tin metal plating solution that can achieve overall excellent matting quality and is easy to operate. be. Means for Solving the Problems The tin metal plating solution provided by the present invention contains the following (a) to (d) as essential components. (a) One or more tin metal salts selected from the group consisting of divalent water-soluble tin salts and water-soluble lead salts. Preferably alkanesulfonates or alkanolsulfonates. Concentration as metal on
It is desirable to set it as 0.5-40g/. tin
In the case of a lead alloy plating solution, the concentration ratio of both metal ions in the solution is adjusted according to the target alloy composition. (b) Alkanesulfonic acid or alkanolsulfonic acid. Preferred specific examples include methanesulfonic acid, ethanesulfonic acid, hydroxyethanesulfonic acid, and hydroxypropanesulfonic acid. These may be the same or different from the acid group of the tin metal salt when the salt is an alkanesulfonate or an alkanolsulfonate, and two or more types may be used in combination. . The concentration is approximately 20 to 180 g/molar, and it is desirable that the amount is 1.5 times or more molar relative to metals such as tin and lead (excluding those forming metal salts). (c) A surfactant comprising a compound having any of the following general formulas (a) to (c). (However, R ₁ is −CH ₂ CH ₂ O−, R ₂ is −CH ₂ CH ₂ −
(represents CH ₂ O-, m and n are integers of 5 to 40) Examples of surfactants made of ethylenediamine polyoxyalkylene adducts having the above general formula (a) include Tetronic 702, Tetronic
704 (Asahi Denka Kogyo product), etc. (However, R ₁ is an alkyl group having 8 to 18 carbon atoms,
R ₂ is −CH ₂ CH ₂ O− or −CH ₂ CH ₂ CH ₂ −O
-, and m and n are integers of 8 to 30) Examples of the surfactant made of polyoxyalkylene alkylamine having the above general formula (b) include Naimeen S-210, Naimeen S-220,
Examples include Naimeen F-215 and Naimeen T _2-230 (products of Nippon Oil & Fats Corporation). (However, R ₁ is an alkyl group having 8 to 18 carbon atoms,
R ₂ is −CH ₂ CH ₂ O− or −CH ₂ CH ₂ CH ₂ −O
-, and m and n are integers of 6 to 24) Examples of surfactants made of fatty acid amide ether sulfate having the above general formula (c) include Nitsusan Sanamide CF-3 (product of NOF Corporation). )and so on. Two or more of these surfactants may be used in combination, and the effect is particularly significant when one of general formula (a) is used in combination with one of (b) or (c). The effect of use appears at a concentration of about 0.5 to 50 g/distance, but a concentration of about 2 to 30 g/mt is suitable for practical use. (d) Organic brighteners. Although there are many brighteners for plating solutions, examples of those that are particularly suitable for the plating solution of the present invention include: aromatics such as benzaldebide, o-chlorobenzaldebide, cinnamaldebide, etc. Aromatic ketones such as benzylidene acetone; Aromatic carboxylic acids such as anthranilic acid and cinnamic acid; Reactants of anthranilic acid and epichlorohydrin; beta-naphthol, thiourea, diethylthiourea. These are usually used at a concentration of 0.01 to 10 g/. Functions and Effects of the Invention The plating liquid of the present invention is formulated with a specific surfactant selected from a large number of surfactants in combination with alkanesulfonic acid or alkanolsulfonic acid and an organic brightener. It is excellent in that it enables satisfactory plating in terms of uniform electrodeposition, stability of alloy composition during alloy plating, and solderability, and produces little foaming during use. EXAMPLES The present invention will be described below with reference to Examples and Comparative Examples. Example 1 A plating solution of 10 g of tin ethanesulfonic acid (10 g of free ethanesulfonic acid), 10 of Nissannaimeen S-220, and 0.1 of benzylidene acetone was prepared, and a tin plate was used as an anode, while stirring gently. When plating was carried out at 20° C. for 5 minutes, the results shown in Table 1 were obtained in the cathode current density range of 0.5 to 10 A/dm ² . Example 2 Tin hydroxyethanesulfonate () 30g/Free hydroxyethanesulfonic acid 150〃Nitsunanimeen S-220 15〃Tetrotsuk 704 10〃O-Chlorobenzaldebide 0.2〃Temperature 25℃ Cathode current density 0.5-10A Plating was carried out in the same manner as in Example 1 under the conditions of / ^dm2 , and the results shown in Table 1 were obtained. Example 3 Tin ethanesulfonate (20g) / Free hydroxyethanesulfonic acid 120〃 Nitsusansanamide CF-3 10〃 Tetronik 702 5〃 Reaction product of anthranilic acid and epichlorohydrin 0.1〃 Temperature 20℃ Cathode current density 1~ Plating was carried out in the same manner as in Example 1 under the conditions of 7 A/dm ² and the results shown in Table 1 were obtained. Comparative example 1 Tin methanesulfonate () 100g/Free methanesulfonic acid 150〃 Cetyldimethylbenzylammonium hydroxide 5〃 N-butylidenesulfanilic acid 2〃 Temperature 35℃ Cathode current density 5 to 40A/dm ² Conditions Plating was carried out in the same manner as in Example 1, and the results shown in Table 1 were obtained. Example 4 Lead methanesulfonate 15g/free methanesulfonic acid 120 Nitsusansanamide CF-3 12 o-chlorobenzaldebide 0.2 Temperature 20°C Cathode current density 0.5 to 10A/dm ² Example Plating was performed in the same manner as in 1, and the results shown in Table 1 were obtained. Comparative Example 2 Lead 2-hydroxypropanesulfonate 20g/Free 2-hydroxypropanesulfonic acid 100 Dodecylpicolinium methanesulfonate 5 N-(3-hydroxybutylidene)-p-sulfanilic acid 1 Temperature 25°C Cathode current Plating was carried out in the same manner as in Example ¹ under conditions of a density of 1 to 10 A/dm2, and the results shown in Table 1 were obtained. Example 5 Tin methanesulfonate () 12g/Lead methanesulfonate 8 Free methanesulfonic acid 120 Nissannaimeen T ₂ -230 10 Tetronik 702 5 Anthranilic acid, epichlorohydrin, and reaction product
0.2〃 Plating was carried out in the same manner as in Example 1 under the conditions of temperature 20° C. and cathode current density 0.5 to 10 A/dm ² , and the results shown in Table 1 were obtained. Example 6 Tin hydroxyethanesulfonate () 18g/ Lead hydroxyethanesulfonate 2 Free hydroxyethanesulfonic acid 100 Nissani Meen S-220 15 Tetronik 704 5 O-Chlorbenzaldehyde 0.2 Temperature 25℃ Cathode Plating was carried out in the same manner as in Example 1 at a current density of 0.5 to 10 A/ ^dm2 , and the results shown in Table 1 were obtained. Example 7 Tin methanesulfonate (24g) / Lead methanesulfonate 16〃 Free methanesulfonic acid 100〃 Nitsusansanamide CF-3 20〃 Tetronik 702 5〃 Diethylthiourea 0.1〃 Cinnamic aldehyde 0.1〃 Temperature 30℃ Cathode Plating was carried out in the same manner as in Example 1 at a current density of 2 to 10 A/ ^dm2 , and the results shown in Table 1 were obtained. Example 8 Tin methanesulfonate () 9g/Lead methanesulfonate 6 Free methanesulfonic acid 100 Nissani Meen S-210 10 Tetronik 704 3 O-chlorobenzaldehyde 0.1 Temperature 20°C Average cathode current density Barrel plating was carried out under the conditions of 0.5 to 1.0 A/dm ² and the results shown in Table 1 were obtained. Comparative Example 3 Tin 2-hydroxypropanesulfonate ()
20g/ Lead 2-hydroxypropanesulfonate 1 Free 2-hydroxypropanesulfonic acid 100 Nonionic surfactant (propylene oxide adduct of styrenated phenol) 5 N-(3-hydroxybutylidene)-p-sulfanyl Plating was carried out in the same manner as in Example 1 under the conditions of acid: 0.3°C, temperature: 25°C, cathode current density: 0.5 to 5 A/dm ² , and the results shown in Table 1 were obtained. Comparative example 4 Tin methanesulfonate () 18g / Lead methanesulfonate 12〃 Free methanesulfonic acid 150〃 Nonionic surfactant (polyoxyethylene nonyl phenyl ether) 3〃 Phenyl salicylate 0.5〃 Temperature 25℃ Cathode current density Plating was carried out in the same manner as in Example ¹ under the conditions of 0.5 to 10 A/dm2, and the results shown in Table 1 were obtained. The evaluation criteria for the evaluation items shown in Table 1 are as follows, and good results are indicated by ◯, fair ones are indicated by △, and poor ones are indicated by ×. Appearance of plating: Appearance and density of plating at current density 0.5 to 7 A/ ^dm2 Uniform electrodeposition: 1 A/d on Hull cell test panel
A film having a small ratio of film thickness at m ² to film thickness at 7 A/dm ² is considered good. Alloy ratio stability: on Hull cell test panel
Plating film at 1A/dm ² and 7A/dm ²
The Sn/Pb ratio is determined for the film in and the one with the smallest difference is considered good. Solderability: Place a small piece of solder on the sample.
Place it on a hot plate at 270±5°C, and the solder grains should have a wide spread area for 5 seconds after they start melting, and the surrounding area of the solder grains should be smooth. 【table】

Claims (1)

[Scope of Claims] 1. A tin metal plating solution characterized by containing the following (a) to (d) as essential components: (a) from a divalent water-soluble tin salt and a water-soluble lead salt. One or more tin metal salts selected from the group consisting of; (b) alkanesulfonic acid or alkanolsulfonic acid; (c) general formula (However, R ₁ is −CH ₂ CH ₂ O−, R ₂ is −CH ₂ CH ₂ −
CH ₂ O-, m and n are integers from 5 to 40) (However, R ₁ is an alkyl group having 8 to 18 carbon atoms,
R ₂ is −CH ₂ CH ₂ O− or −CH ₂ CH ₂ CH ₂ −O
-, m and n are integers from 8 to 30) or (However, R ₁ is an alkyl group having 8 to 18 carbon atoms,
R ₂ is −CH ₂ CH ₂ O− or −CH ₂ CH ₂ CH ₂ −O
-, m and n are integers of 6 to 24); (iv) an organic brightener; 2 The concentration of tin metal salt is 0.5 as metal ion.
The plating solution according to claim 1, which is within the range of ~40g/. 3. The plating solution according to claim 1, wherein the concentration of alkanesulfonic acid or alkanolsulfonic acid is within the range of 20 to 180 g/l. 4. The plating solution according to claim 1, wherein the concentration of the surfactant is within the range of 0.5 to 50 g/g/. 5. The plating solution according to claim 1, wherein the concentration of the organic brightener is within the range of 0.01 to 10 g/g/. 6. The plating solution according to claim 1, wherein the tin group metal salt is an alkanesulfonate or an alkanolsulfonate.