[0002] 已知於導電性物體上形成錫合金鍍膜，例如錫-銀合金鍍膜所使用之錫合金鍍敷浴(液)，於浴中之錫離子與其他金屬離子(例如銀離子)之氧化還原電位差異較大時，易因比錫貴重之金屬離子於鍍敷浴中生成不溶性之鹽或金屬單體而析出，故難安定保持鍍敷液。因此先前係使用例如作為錫-銀合金鍍敷液用之含有氰化合物的鍍敷液。但因此浴含有有毒之氰化合物，而使毒性極高，故處理上會有各種問題。 [0003] 先前有關不含氰化合物之錫合金鍍敷液已有各種鍍敷浴(液)提案(例如參考專利文獻1~4)。專利文獻1係揭示非氰系的安定之銀及銀合金鍍敷浴，此銀及銀合金鍍敷浴為，含有(A)由銀鹽，與銀鹽及錫、鉍、銦、鉛等之金屬的鹽之混合物中任一種所形成之可溶性鹽，及(B)分子內具有1個以上之鹼性氮原子的2,2’-二吡啶基硫化物、2,2’-二哌嗪基二硫化物等之特定硫化物系化合物，或1-氮雜-7-噁-4,10-二硫雜環十二烷等之特定硫冠醚化合物。此鍍敷浴因含有此等特定化合物，故比較巰基乙酸等之含有其他硫系化合物之浴時，可得優良之鍍敷浴經時安定性、銀與各種金屬之共析化、電鍍被膜之外觀等。 [0004] 專利文獻2係揭示非氰系的安定之銀及銀合金鍍敷浴，此銀及銀合金鍍敷浴為，含有(A)由銀鹽，與銀鹽及錫、鉍、銦、鉛等之金屬的鹽之混合物中任一種所形成的可溶性鹽，及(B)分子內具有1個以上之醚性氧原子、1-羥基丙基或羥基伸丙基，且不具有鹼性氮原子之硫雙(二乙二醇)、二硫雙(三甘油)、3,3’-硫二丙醇、硫二甘油等之特定的脂肪族硫化物系化合物。使用此鍍敷浴會因含有此等特定化合物，故比較含有不具有醚性氧原子、1-羥基丙基或羥基伸丙基之脂肪族單硫化物化合物的硫二甘醇酸或β-硫二甘醇之浴，可得優良之鍍敷浴經時安定性、銀與各種金屬之共析化、電鍍被膜之外觀等。 [0005] 專利文獻3係揭示非氰系的錫-銀合金鍍敷浴，此錫-銀合金鍍敷浴為，含有(a)脂肪族胺基酸類、含氮之芳香族羧酸類中至少一種，及(b)脂肪族硫化物類、脂肪族硫醇類中至少一種。(a)之脂肪族胺基酸類如甘胺酸等，(a)之含氮的芳香族羧酸類如皮考啉酸、3-胺基吡嗪-2-羧酸等，(b)之脂肪族硫化物類如4,7-二硫雜癸烷-1,10-二醇等，脂肪族硫醇類如硫甘醇等。此鍍敷浴中成分(b)之硫化合物係作為銀之安定劑用，另外併用甘胺酸或皮考啉酸等之成分(a)可良好提升錫-銀合金被膜之焊錫潤濕性與外觀。 [0006] 專利文獻4係揭示不含氰化物之銀系鍍敷浴，此鍍敷浴為，含有具有銀鹽之可溶性鹽，與由特別之一般式所表示之化合物所成群中所選出之一種以上的硫化物系化合物。藉由此鍍敷浴可改善浴中之銀離子的安定性，可得到充分之錯合物化力，同時可減少生產成本，具有優良實用性。 [先前技術文獻] 專利文獻 [0007] 專利文獻1：特開平11-269691號公報(要約) 專利文獻2：特開2000-192279號公報(要約) 專利文獻3：特開2006-265572號公報(要約) 專利文獻4：特開2007-046142號公報(要約)[0002] It is known to form a tin alloy plating film on a conductive object, such as a tin alloy plating bath (liquid) used in a tin-silver alloy plating film, and oxidation of tin ions and other metal ions (such as silver ions) in the bath When the difference in reduction potential is large, it is easy to precipitate insoluble salts or metal monomers in the plating bath due to metal ions more precious than tin, so it is difficult to stabilize and maintain the plating solution. Therefore, for example, a plating solution containing a cyan compound as a tin-silver alloy plating solution has been used previously. But because the bath contains toxic cyanide compounds, which makes the toxicity extremely high, so there will be various problems in handling. [0003] Previously, various plating baths (liquids) have been proposed regarding tin alloy plating solutions that do not contain cyanide compounds (for example, refer to Patent Documents 1 to 4). Patent Document 1 discloses a non-cyanide stable silver and silver alloy plating bath. The silver and silver alloy plating bath contains (A) silver salts, silver salts and tin, bismuth, indium, lead, etc. A soluble salt formed by any one of a mixture of metal salts, and (B) 2,2'-dipyridyl sulfide, 2,2'-dipiperazinyl having more than one basic nitrogen atom in the molecule Specific sulfide compounds such as disulfides, or specific sulfur crown ether compounds such as 1-aza-7-oxa-4,10-dithiocyclododecane. This plating bath contains these specific compounds, so when comparing thioglycolic acid and other baths containing other sulfur compounds, excellent plating bath stability over time, eutectoidization of silver and various metals, and plating coatings can be obtained Appearance, etc. [0004] Patent Document 2 discloses a non-cyanide stable silver and silver alloy plating bath. The silver and silver alloy plating bath contains (A) a silver salt, a silver salt, and tin, bismuth, indium, A soluble salt formed by any mixture of salts of metals such as lead, and (B) has more than one etheric oxygen atom, 1-hydroxypropyl group or hydroxypropyl group in the molecule, and does not have a basic nitrogen Atomic sulfur bis (diethylene glycol), disulfide bis (triglyceride), 3,3'-thiodipropanol, sulfur diglycerol and other specific aliphatic sulfide compounds. Since this plating bath contains these specific compounds, sulfur diglycolic acid or β-sulfur containing aliphatic monosulfide compounds that do not have an etheric oxygen atom, 1-hydroxypropyl or hydroxypropylene is more The diethylene glycol bath provides excellent plating bath stability over time, the eutectoidization of silver and various metals, and the appearance of the plating film. [0005] Patent Document 3 discloses a non-cyanide tin-silver alloy plating bath. The tin-silver alloy plating bath contains at least one of (a) aliphatic amino acids and nitrogen-containing aromatic carboxylic acids. , And (b) at least one of aliphatic sulfides and aliphatic thiols. (a) aliphatic amino acids such as glycine, etc., (a) nitrogen-containing aromatic carboxylic acids such as picolinic acid, 3-aminopyrazine-2-carboxylic acid, etc., (b) fat Group sulfides such as 4,7-dithiodecane-1,10-diol and the like, and aliphatic thiols such as thioglycol and the like. The sulfur compound of component (b) in this plating bath is used as a stabilizer for silver. In addition, the use of component (a) such as glycine or picoline acid can improve the solder wettability and tin-silver alloy coating. Exterior. [0006] Patent Document 4 discloses a silver-based plating bath that does not contain cyanide. The plating bath contains a soluble salt having a silver salt, and is selected from the group consisting of compounds represented by a special general formula More than one sulfide compound. By this plating bath, the stability of silver ions in the bath can be improved, and sufficient complexing power can be obtained, at the same time, the production cost can be reduced, and it has excellent practicality. [Prior Art Literature] Patent Literature [0007] Patent Literature 1: Japanese Patent Laid-Open No. 11-269691 (Offer) Patent Literature 2: Japanese Patent Laid-Open No. 2000-192279 (Offer) Patent Literature 3: Japanese Patent Laid-Open No. 2006-265572 ( Offer) Patent Document 4: Japanese Patent Laid-Open No. 2007-046142 (Offer)
發明所欲解決之課題 [0008] 上述專利文獻1~4之鍍敷浴為了鍍敷浴中銀離子之安定性及鍍敷浴經時安定性，而含有使銀被錯合物化用之各種錯合物化劑。但專利文獻1~4所示之錯合物化劑於長期使用鍍敷浴及長期保管鍍敷浴時，易有分解而析出銀之問題。又錯合物化劑於鍍敷浴中具有較高安定性時，相對於鍍膜之外觀及膜厚均勻性會有不良影響。 [0009] 本發明之目的為，提供具有優良電解安定性及經時安定性，且使鍍膜具有良好外觀及膜厚均勻性之錫合金鍍敷液。 解決課題之方法 [0010] 本發明者們為了解決上述課題經專心研究後發現，錫合金鍍敷液含有特定硫化物化合物時，既使於使用中或保管中也不會使鍍敷浴中比錫貴重之金屬的錯合物分解而安定化，可得非常良好之鍍膜外觀及膜厚均勻性，而達成本發明。 [0011] 本發明之第1觀點為一種錫合金鍍敷液，其為含有可溶性錫鹽、比錫貴重之金屬的可溶性鹽，與下述一般式(1)所表示之硫化物化合物，式(1)中，n為1~3。 [0012][0013] 本發明之第2觀點如第1觀點之發明的錫合金鍍敷液，其中另含有由陰離子表面活性劑、陽離子表面活性劑、非離子系表面活性劑及兩性表面活性劑中所選出之一種或二種以上之表面活性劑。 [0014] 本發明之第3觀點如第1或第2觀點之發明的錫合金鍍敷液，其中比前述錫貴重之金屬為，由銀、銅、金及鉍中所選出之至少一種或二種以上之金屬。 [0015] 本發明之第4觀點如第1至第3觀點中任一觀點之發明的錫合金鍍敷液，其中另含有防氧化劑。 [0016] 本發明之第5觀點如第1至第4觀點中任一觀點之發明的錫合金鍍敷液，其中另含有鍚用之錯合物化劑。 [0017] 本發明之第6觀點如第1至第5觀點中任一觀點之發明的錫合金鍍敷液，其中另含有pH調整劑。 [0018] 本發明之第7觀點如第1至第6觀點中任一觀點之發明的錫合金鍍敷液，其中另含有光澤化劑。 發明之效果 [0019] 本發明之第1觀點的錫合金鍍敷液中，硫化物化合物因如上述一般式(1)所表示，分子中含有氧原子「 -O-」，故藉由與水之氫鍵結，可有效提升水溶性。又藉由S原子間存在醚鍵「C-O-C」，可使化合物本身具有優良安定性，且因含有2~4個S原子，故此S原子可使鍍敷浴中比錫貴重之金屬離子充分錯合物化而安定化。因此此錫合金鍍敷液既使於使用中或保管中在長時間下亦可具有優良電解安定性及經時安定性。又，為了使硫化物化合物適當吸附於鍍敷電極表面而併用作為平滑化劑用之表面活性劑時，不會阻礙表面活性劑之作用，可得到良好之鍍膜外觀及膜厚均勻性。 [0020] 本發明之第2觀點的錫合金鍍敷液中，因另含有陰離子表面活性劑、陽離子表面活性劑、非離子系表面活性劑、兩性表面活性劑等之表面活性劑，故可有效得到更良好之鍍膜外觀及膜厚均勻性。 [0021] 本發明之第3觀點的錫合金鍍敷液中，因此比錫貴重之金屬係由銀、銅、金及鉍中所選出之至少一種或二種以上，故可有效得到優良之焊錫潤濕性、實裝強度、彎曲性及回流性，不易生成晶鬚等。 [0022] 本發明之第4觀點的錫合金鍍敷液中，因另含有防氧化劑，故可有效防止錫合金鍍敷液中Sn2+
氧化。 [0023] 本發明之第5觀點的錫合金鍍敷液中，因另含有錫用之錯合物化劑，故錫合金鍍敷液使用於近中性之錫鍍敷浴時可有效使Sn2+
離子安定化。 [0024] 本發明之第6觀點的錫合金鍍敷液中，因另含有pH調整劑，故可有效將錫合金鍍敷液調整為酸性、弱酸性、中性等任意之pH領域。 [0025] 本發明之第7觀點的錫合金鍍敷液中，因另含有光澤劑，故具有可有效使錫合金鍍膜中錫合金之結晶粒子微細化的作用。 實施發明之形態 [0026] 下面將說明本發明一實施形態之錫合金鍍敷液。此錫合金鍍敷液係作為使用於半導體基板(晶圓)或印刷基板用之焊錫凸塊等的形成錫合金鍍膜之材料用。 [0027] 本實施形態之錫合金鍍敷液為，含有可溶性錫鹽、比錫貴重之金屬的可溶性鹽，與下述一般式(1)所表示之硫化物化合物。式(1)中，n為1~3。 [0028][0029] [錫合金] 本實施形態之由錫合金鍍敷液所製作之錫合金為，錫(Sn)與由銀(Ag)、銅(Cu)、金(Au)、鉍(Bi)中所選出之特定金屬的合金，例如SnAg合金、SnCu合金、SnAu合金、SnBi合金等之二元合金、SnCuAg合金等之三元合金。 [0030] [可溶性錫鹽] 本實施形態之錫合金鍍敷液所使用的可溶性錫鹽為，溶解於水後會生成二價錫離子之鹽。可溶性錫鹽如，鹵化物、硫酸鹽、氧化物、鏈烷磺酸鹽、芳基磺酸鹽及烷醇磺酸鹽。鏈烷磺酸鹽之具體例如，甲烷磺酸鹽及乙烷磺酸鹽。芳基磺酸鹽之具體例如，苯磺酸鹽、苯酚磺酸鹽、甲酚磺酸鹽及甲苯磺酸鹽。烷醇磺酸鹽之具體例如，羥乙磺酸鹽。 [0031] 可溶性錫鹽可單獨使用一種或二種以上組合使用。本實施形態之錫合金鍍敷液中可溶性錫鹽之含量換算為錫量較佳為5 g/L以上200 g/L以下之範圍，更佳為20 g/L以上100 g/L以下之範圍。可溶性錫鹽之含量太少時，一般凸塊電鍍所使用之電流密度1~20ASD(每1平方dm之安培)的範圍內不易正常析出錫，恐無法形成良好凸塊。又，可溶性錫鹽之含量過高時，會因鍍敷液之黏度較高而不易形成凸塊，另外因含有必要以上之錫，故恐提高鍍敷浴之成本。 [0032] [比錫貴重之金屬的可溶性鹽] 本實施形態之錫合金鍍敷液所使用的比錫貴重之金屬的可溶性鹽為，能溶解於水之鹽。比錫貴重之金屬可為，由銀、銅、金及鉍中所選出之至少一種或二種以上之金屬。此等金屬之可溶性鹽之例示與可溶性錫鹽之例示相同。此等金屬中較佳為含有銀或銅。錫與銀之合金(SnAg合金)為，共晶組成(Sn-3.5wt% Ag)之熔點為221℃的低熔點，又錫與銅之合金(SnCu合金)為，共晶組成(Sn-1.7wt% Cu)之熔點為227℃的低熔點，故任一種均有優良焊錫潤濕性、實裝強度、彎曲性及回流性，且不易生成晶鬚之優點。比錫貴重之金屬的可溶性鹽可單獨使用一種或二種以上組合使用。本實施形態之鍍敷液中比錫貴重之金屬的可溶性鹽含量換算為金屬量時，較佳為0.01 g/L以上10 g/L以下之範圍，更佳為0.1 g/L以上2 g/L以下之範圍。比錫貴重之金屬的可溶性鹽含量過少或過多時，所析出之焊錫合金的組成無法為共晶組成，故無法得到作為焊錫合金用之特性。 [0033] [硫化物化合物] 本實施形態之錫合金鍍敷液所使用的硫化物化合物如上述一般式(1)所表示，係由濃硫酸或烷基磺酸等之具有脫水作用的強酸中使硫二乙醇(n=0)脫水縮合所得。此時藉由變更反應溫度、反應時間及精製條件，可控制一般式(1)中n之值。此n超過3時硫化物化合物將無法為水溶性，具有排水性。因此為了使硫化物化合物溶解於水溶液中，n需為3以下。如上述般，硫化物化合物為上述一般式(1)中，分子中係含有氧原子「-O-」，因此藉由與水之氫鍵結，可有效提升水溶性。又藉由S原子間存在醚鍵「C-O-C」，可使化合物本身具有優良安定性，且因1分子中含有2~4個S原子，故此S原子可使鍍敷浴中比錫貴重之金屬離子充分錯合物化而安定化。此硫化物化合物之結構可藉由併用高速液體色譜(HPLC)、高速液體色譜圖質量分析計(LC-MS)、傅里葉變換紅外分光法(FT-IR)、核磁共振裝置(NMR)等之分析機器進行分析。 [0034] [添加劑] 本實施形態之錫合金鍍敷液可另含有酸電解質(游離酸)、表面活性劑、防氧化劑、錫用之錯合物化劑、pH調整劑、光澤化劑等之添加劑。 [0035] (酸電解質) 酸電解質如，氯化氫、溴化氫、硫酸、鏈烷磺酸、芳基磺酸或烷醇磺酸。鏈烷磺酸之具體例如，甲烷磺酸或乙烷磺酸。芳基磺酸之具體例如，苯磺酸、苯酚磺酸、甲酚磺酸或甲苯磺酸。烷醇磺酸之具體例如，羥乙磺酸。酸電解質為具有提高錫合金鍍敷液之導電性的作用。 [0036] 酸電解質可單獨使用一種或二種以上組合使用。本實施形態之錫合金鍍敷液中酸電解質之含量較佳為5 g/L以上500 g/L以下之範圍，更佳為30 g/L以上300 g/L以下之範圍。 [0037] (表面活性劑) 本實施形態之錫合金鍍敷液較佳為含有表面活性劑。表面活性劑具有提高錫合金鍍敷液與被鍍敷物之親和性的作用，與藉由形成錫合金鍍膜時會吸附於鍍膜表面而抑制鍍膜內錫合金之結晶成長，經由結晶微細化結果，可提升鍍膜之外觀、提升與被鍍敷物之密合性、使膜厚均勻化等之作用。表面活性劑可使用陰離子表面活性劑、陽離子表面活性劑、非離子系表面活性劑及兩性表面活性劑等之各種表面活性劑。 [0038] 陰離子表面活性劑之具體例如，烷基硫酸鹽、聚氧乙烯烷基醚硫酸鹽、聚氧乙烯烷基苯基醚硫酸鹽、烷基苯磺酸鹽、烷基萘磺酸鹽等。陽離子表面活性劑之具體例如，單~三烷基胺鹽、二甲基二烷基銨鹽、三甲基烷基銨鹽等。非離子系活性劑之具體例如，碳原子數1~20之烷醇、苯酚、萘酚、雙酚類、碳原子數1~25之烷基苯酚、芳基烷基苯酚、碳原子數1~25之烷基萘酚、碳原子數1~25之烷氧基磷酸(鹽)、山梨糖醇酐酯、聚烷二醇、碳原子數1~22之脂肪族醯胺等附加縮合2~300莫耳之環氧(EO)及/或環氧丙烷(PO)所得之物等。兩性表面活性劑之具體例如，羧基甜菜鹼、咪唑啉甜菜鹼、胺基羧酸等。 [0039] 表面活性劑可單獨使用一種或二種以上組合使用。本實施形態之錫合金鍍敷液中表面活性劑之添加量一般為0.01 g/L以上50 g/L以下之範圍，較佳為0.1 g/L以上20 g/L以下之範圍，更佳為1 g/L以上10 g/L以下之範圍。 [0040] (防氧化劑) 本實施形態之錫合金鍍敷液於必要時可含有防氧化劑。防氧化劑之目的為，防止錫合金鍍敷液中Sn2+
氧化。防氧化劑如，抗壞血酸或其鹽、焦棓酚、氫醌、間苯二醇、三羥基苯、兒茶酚、甲酚磺酸或其鹽、兒茶酚磺酸或其鹽、氫醌磺酸或其鹽等。例如酸性浴中較佳為氫醌磺酸或其鹽，中性浴中較佳為抗壞血酸或其鹽等。 [0041] 防氧化劑可單獨使用一種或二種以上組合使用。本實施形態之錫合金鍍敷液中防氧化劑之添加量一般為0.01 g/L以上20 g/L以下之範圍，較佳為0.1 g/L以上10 g/L以下之範圍，更佳為0.1 g/L以上5 g/L以下之範圍。 [0042] (錫用之錯合物化劑) 本實施形態之錫合金鍍敷液適用於酸性、弱酸性、中性等任意pH領域之錫合金鍍敷浴。Sn2+
離子於強酸性(pH：＜1)中為安定，但於酸性至中性附近(pH：1~7)中易生成白色沈澱。因此將本實施形態之錫合金鍍敷液適用於近中性之錫鍍敷浴時，為了使Sn2+
離子安定化的目的，較佳為添加錫用之錯合物化劑。 [0043] 錫用之錯合物化劑可使用氧基羧酸、聚羧酸、單羧酸。具體例如，葡萄酸、檸檬酸、葡庚糖酸、葡萄酸內酯、乙酸、丙酸、丁酸、抗壞血酸、草酸、丙二酸、琥珀酸、乙醇酸、蘋果酸、酒石酸或此等之鹽等。較佳為葡糖酸、檸檬酸、葡庚糖酸、葡萄酸內酯、葡庚糖酸內酯或此等之鹽等。又，伸乙基二胺、伸乙基二胺四乙酸(EDTA)、二伸乙基三胺五乙酸(DTPA)、氰基三乙酸(NTA)、亞胺基二乙酸(IDA)、亞胺基二丙酸(IDP)、羥基乙基伸乙基二胺三乙酸(HEDTA)、三伸乙基四胺六乙酸(TTHA)、伸乙基二氧基雙(乙基胺)-N,N,N’,N’-四乙酸、巰基三唑類、巰基四唑類、甘胺酸類、氰基三甲基膦酸、1-羥基乙烷-1,1-二膦酸或此等之鹽等之聚胺或胺基羧酸類也適用為錯合物化劑。 [0044] 錫用之錯合物化劑可單獨使用一種或二種以上組合使用。本實施形態之錫合金鍍敷液中錫用之錯合物化劑的添加量，相對於錫合金鍍敷液所含之可溶性錫鹽化合物中錫1莫耳一般為0.001莫耳以上10莫耳以下之範圍，較佳為0.01莫耳以上5莫耳以下之範圍，更佳為0.5莫耳以上2莫耳以下之範圍。 [0045] (pH調整劑) 本實施形態之錫合金鍍敷液於必要時可含有pH調整劑。pH調整劑如，鹽酸、硫酸等之各種酸、氨水、氫氧化鉀、氫氧化鈉、碳酸氫鈉等之各種鹼等。又，作為pH調整劑，乙酸、丙酸等之單羧酸、硼酸類、磷酸類、草酸、琥珀酸等之二羧酸類、乳酸、酒石酸等之氧基羧酸類等亦為有效者。 [0046] (光澤化劑) 本實施形態之錫合金鍍敷液於必要時可含有光澤化劑。作為光澤化劑，芳香族羰基化合物為有效者。芳香族羰基化合物具有使錫合金鍍膜中錫合金之結晶粒子微細化的作用。芳香族羰基化合物為，芳香族烴之碳原子鍵結羰基(-CO-X，但X為氫原子、羥基、碳原子數1~6範圍之烷基或碳原子數1~6範圍之烷氧基)的化合物。芳香族烴為含有苯環、萘環及蒽環。芳香族烴可具有取代基。取代基如，鹵素原子、羥基、碳原子數1~6範圍之烷基及碳原子數1~6範圍之烷氧基。羰基可直接鍵結於芳香族烴，或介有碳原子數1以上6以下之範圍的伸烷基而鍵結。芳香族羰基化合物之具體例如，亞苄基丙酮、肉桂酸、肉桂醛、苯醛。 [0047] 芳香族羰基化合物可單獨使用一種或二種以上組合使用。本實施形態之錫合金鍍敷液中芳香族羰基化合物之添加量一般為0.01 mg/L以上500 mg/L以下之範圍，較佳為0.1 mg/L以上100 mg/L以下之範圍，更佳為1 mg/L以上50 mg/L以下之範圍。 [0048] 本實施形態之錫合金鍍敷液例如可藉由混合可溶性錫鹽、比錫貴重之金屬的可溶性鹽、上述一般式(1)所表示之硫化物化合物及其他成分，與水而調製。為了抑制Sn2+
離子氧化及比錫貴重之金屬離子的還原反應較佳為，投入硫化物化合物後，再混合比錫貴重之金屬的可溶性鹽。 [0049] 使用本實施形態之鍍敷液的鍍膜形成方法可使用上述般電氣電鍍法。藉由電氣電鍍形成鍍膜時之電流密度為0.1 A/dm2
以上100 A/dm2
以下之範圍，較佳為0.5 A/dm2
以上20 A/dm2
以下之範圍。液溫為10℃以上50℃以下之範圍，更佳為20℃以上40℃以下之範圍。PROBLEM TO BE SOLVED BY THE INVENTION [0008] The plating baths of the above-mentioned Patent Documents 1 to 4 contain various conjugates for the complexation of silver in order to stabilize the silver ions in the plating bath and the stability of the plating bath over time. Physicochemical agent. However, when the complexing agent shown in Patent Documents 1 to 4 is used for a long period of time and the plating bath is stored for a long period of time, there is a problem of decomposition and precipitation of silver. In addition, when the complexing agent has high stability in the plating bath, it will have an adverse effect on the appearance of the plating film and the uniformity of the film thickness. [0009] An object of the present invention is to provide a tin alloy plating solution having excellent electrolytic stability and stability over time, and having a good appearance and uniformity of film thickness of a plating film. Methods for Solving the Problems [0010] The inventors have made intensive studies to solve the above problems and found that when the tin alloy plating solution contains a specific sulfide compound, it does not cause the plating bath to be used even during use or storage. The complex of tin precious metal is decomposed and stabilized, and a very good appearance of the coating and uniformity of the film thickness can be obtained, and the invention can be achieved. [0011] The first aspect of the present invention is a tin alloy plating solution, which is a soluble salt containing a soluble tin salt, a metal more precious than tin, and a sulfide compound represented by the following general formula (1), formula ( In 1), n is 1~3. [0012] 
實施例 [0050] 其次將詳細說明本發明之實施例與比較例。 [0051] (SnAg鍍敷液之建浴) ＜實施例1＞ 將作為游離酸用之甲烷磺酸、作為錯合物化劑用之一般式(1)之n=1的硫化物化合物，與非離子系表面活性劑(以50：50之比例將聚氧乙烯與聚氧丙烯附加於伸乙基二胺所得之物)混合、溶解於甲烷磺酸錫水溶液後，再加入甲烷磺酸銀液混合。最後加入離子交換水，使下述組成之SnAg鍍敷液建浴。又，係各自藉由於甲烷磺酸水溶液中電解金屬錫板及金屬銀板，而調製甲烷磺酸錫水溶液及甲烷磺酸銀水溶液。 [0052] (SnAg鍍敷液之組成) 甲烷磺酸錫(Sn2+
用)：50 g/L 甲烷磺酸銀(Ag+
用)：0.5 g/L 甲烷磺酸(游離酸用)：150 g/L 硫化物化合物(n=1)：5 g/L 非離子系表面活性劑：5 g/L 離子交換水：殘部 [0053] ＜實施例2＞ 除了錯合物化劑係使用一般式(1)之n=2的硫化物化合物外，與實施例1相同使SnAg鍍敷液建浴。 [0054] ＜實施例3＞ 除了錯合物化劑係使用一般式(1)之n=3的硫化物化合物外，與實施例1相同使SnAg鍍敷液建浴。 [0055] ＜實施例4＞ 將作為游離酸用之甲烷磺酸、作為錯合物化劑用之一般式(1)之n=2的硫化物化合物混合、溶解於甲烷磺酸錫水溶液後，再加入甲烷磺酸銅水溶液混合。混合形成均勻溶液後，再加入非離子系表面活性劑。最後加入離子交換水，使下述組成之SnCu鍍敷液建浴。又，係各自藉由於甲烷磺酸水溶液中電解金屬錫板及金屬銅板，而調製甲烷磺酸錫水溶液及甲烷磺酸銅水溶液。 [0056] (SnCu鍍敷液之組成) 甲烷磺酸錫(Sn2+
用)：50 g/L 甲烷磺酸銅(Cu2+
用)：0.3 g/L 甲烷磺酸(游離酸用)：150 g/L 硫化物化合物(n=2)：5 g/L 非離子系表面活性劑：5 g/L 離子交換水：殘部 [0057] ＜實施例5＞ 將作為游離酸用之甲烷磺酸、作為錯合物化劑用之一般式(1)之n=1的硫化物化合物，與非離子系表面活性劑(將20莫耳之聚氧乙烯附加於雙酚A1莫耳所得之物)混合，溶解於甲烷磺酸錫水溶液後，加入作為錫用之錯合物化劑用的葡萄糖酸鈉，及巰基四唑，再混合作為光澤化劑用之亞苄基丙酮。其後加入甲烷磺酸銀液混合。最後加入離子交換水，使下述組成之SnAg鍍敷液建浴。 [0058] (SnAg鍍敷液之組成) 甲烷磺酸錫(Sn2+
用)：80 g/L 甲烷磺酸銀(Ag+
用)：1.0 g/L 甲烷磺酸(游離酸用)：100 g/L 硫化物化合物(n=1)：3 g/L 非離子系表面活性劑：8 g/L 葡萄糖酸鈉：10 g/L 巰基四唑：1 g/L 亞苄基丙酮：0.01 mg/L 離子交換水：殘部 [0059] ＜比較例1＞ 除了錯合物化劑係使用一般式(1)之n=0的硫化物化合物外，與實施例1相同使SnAg鍍敷液建浴。 [0060] ＜比較例2＞ 除了錯合物化劑係使用一般式(1)之n=4的硫化物化合物外，與實施例1相同使SnAg鍍敷液建浴。 [0061] ＜比較例3＞ 除了錯合物化劑係使用3,6-二硫雜-1,8-辛二醇外，與實施例1相同使SnAg鍍敷液建浴。 [0062] ＜比較例4＞ 除了錯合物化劑係使用一般式(1)之n=4的硫化物化合物外，與實施例5相同使SnAg鍍敷液建浴。 [0063] ＜比較試驗及評估＞ 使用實施例1~5及比較例1~4之九種建浴後的鍍敷液，評估錫合金鍍敷液之安定性與鍍敷性能。錫合金鍍敷液之安定性係藉由進行電解安定性試驗與經時安定性試驗進行評估。鍍敷性能係藉由進行薄膜電池(hull cell)試驗及電鍍試驗進行評估。 [0064] (a)電解安定性試驗 以九種建浴後之錫合金鍍敷液為電解液，各自將作為陰極之銅板及作為陽極之鉑板配置於此電解液中，以浴溫 25℃、陰極電流密度10ASD各自使九種建浴後之錫合金鍍敷液進行電解電鍍。因藉由電解電鍍會消耗鍍敷液中之金屬成分，故每電解電鍍5 Ah/L投入、混合、溶解氧化亞錫(SnO)與氧化銀(Ag2
O)之粉末，將金屬成分補給鍍敷浴，同時進行電解電鍍至200 Ah/L。電解電鍍後藉由下述HPLC (High Performance Liquid Chromatography)法定量分析錫合金鍍敷液中殘存之錯合物化劑用的硫化物化合物濃度。以一次性注射器過濾錫合金鍍敷液後，使用島津製作所製之HPLC裝置(型號Prominence)，以MeOH(甲醇)作為移動相，使用保溫為40℃之L-ColumnODS進行分析。以建浴當下之錯合物化劑的濃度為100%，將電解電鍍後錯合物化劑之殘存比例(%)評估為錯合物化劑之殘存量。 [0065] (b)經時安定性試驗 各自將九種建浴後之錫合金鍍敷液放入玻璃製密封瓶後，保管於50℃之Panasonic製之無菌爐內6個月。使用島津製作所製之ICP發光分析裝置(ICP-AES、型號ICPE-9800)，各自以建浴當下之錫合金鍍敷液中Sn以外之金屬濃度，即SnAg合金鍍敷液時之Ag濃度、SnCu鍍敷液時之Cu濃度為100%，測定保管6個月後殘存之Sn以外的金屬濃度，即SnAg合金鍍敷液時之Ag濃度、SnCu鍍敷液時之Cu濃度的各殘存比例(%)。 [0066] (c)薄膜電池試驗 各自將九種建浴後之錫合金鍍敷液放入山本鍍金試驗器公司製之薄膜電池槽後，各自將作為陰極之銅製薄膜電池板及作為陽極之鉑板配置於液中，進行薄膜電池試驗。電鍍條件為，液溫25℃、通電電流3A、電鍍處理時間5分鐘。電鍍處理中以陰極搖杆攪拌鍍敷液。評估薄膜電池時係利用電流密度早見板(chart plate)以目視確認電鍍處理後薄膜電池板上鍍膜之被膜外觀，再以將具有光澤、半光澤之被膜視為「良好」，具有無光澤、混濁之被膜視為「可」，焦黑、燒傷之被膜視為「不良」的3種判斷基準進行評估。 [0067] (d)電鍍試驗 各自以九種建浴後之錫合金鍍敷液作為電解液進行電鍍試驗。將電解液之液溫調整為25℃後，將銅製基板(長10cm、寬10cm、厚0.3mm)浸漬於電解液中，以5 A/dm2
之電流密度進行10分鐘。使用螢光X線膜厚測定器(日立高科技公司製)測定所得電鍍被膜之10個部位的膜厚度。求取10個部位之膜厚的最大值(Tmax
)與最小值(Tmin
)與平均值(Taverage
)，再由下述式(2)算出膜厚均勻性，評估是否可均勻電鍍。上述試驗結果如表1所示。 膜厚均勻性=(Tmax
-Tmin
)/(2×Taverage
)×100(%) (2) [0068][0069] 由表1得知，使用一般式(1)中n=0~3所表示之硫化物化合物的實施例1~5為，電解電鍍後SnAg鍍敷液會以90%~95%、SnCu鍍敷液會以88%之高比例殘存錯合物化劑，且經時放置後於液中的Ag或Cu之殘存率也較高，SnAg鍍敷液為84%~97%，SnCu鍍敷液為89%，同時鍍敷性能中被膜外觀也良好，又膜厚均勻性也良好，SnAg鍍敷液為2.1%~ 4.2%，SnCu鍍敷液為3.2%。另外比較例1雖具有良好之電解安定性及鍍敷性能，但經時後會降低Ag之殘存率。其因為，比較例1所使用之n=0的化合物為一分子中具有1個S原子，故與Ag離子之錯合物化能力不足，因此推斷會還原析出Ag。又比較例2及比較例4雖具有良好之鍍敷液的安定性，但鍍敷性能差。其因為，n=4之化合物的排水性較高，相對於電極表面之吸附力較強，故推斷會阻礙併用之表面活性劑的平滑化作用。另外比較例3雖具有良好鍍敷性能，但因錫合金鍍敷液未含作為錯合物化劑用之本發明的硫化物化合物，故電解電鍍後錯合物化劑之濃度較低。 產業上利用可能性 [0070] 本發明之鍍敷液適用於形成半導體晶圓及印刷基板之凸塊電極等般之部分電子構件。Examples [0050] Next, examples and comparative examples of the present invention will be described in detail. [Building Bath of SnAg Plating Solution] <Example 1> The methanesulfonic acid used as a free acid and the sulfide compound of n=1 in the general formula (1) used as a complexing agent are used instead of Ionic surfactant (a product obtained by adding polyoxyethylene and polyoxypropylene to ethylidene diamine at a ratio of 50:50), dissolving in tin methanesulfonate aqueous solution, and then adding silver methanesulfonate to mix . Finally, ion-exchanged water was added to make a bath of SnAg plating solution of the following composition. In addition, the tin methanesulfonate aqueous solution and the silver methanesulfonate aqueous solution are prepared by electrolyzing the metal tin plate and the metal silver plate in the methanesulfonic acid aqueous solution, respectively. [0052] (Composition of SnAg plating solution) Tin methanesulfonate (for Sn 2+ ): 50 g/L silver methanesulfonate (for Ag + ): 0.5 g/L methanesulfonic acid (for free acid): 150 g/L sulfide compound (n=1): 5 g/L nonionic surfactant: 5 g/L ion-exchanged water: residual part [0053] <Example 2> Except for the complex compound system, the general formula ( 1) Except for the sulfide compound with n=2, the SnAg plating solution was bathed in the same manner as in Example 1. [Example 3] The SnAg plating solution was bathed in the same manner as in Example 1, except that the complex compound was a sulfide compound of n=3 in general formula (1). [0055] <Example 4> After mixing methanesulfonic acid as a free acid and a sulfide compound of n=2 of the general formula (1) as a complexing agent, and dissolving in a tin methanesulfonate aqueous solution, Add copper methanesulfonate aqueous solution and mix. After mixing to form a homogeneous solution, non-ionic surfactants are added. Finally, ion-exchanged water was added to make a bath of SnCu plating solution of the following composition. In addition, the tin methanesulfonate aqueous solution and the copper methanesulfonate aqueous solution are prepared by electrolyzing the metal tin plate and the metal copper plate in the methanesulfonic acid aqueous solution, respectively. [0056] (Composition of SnCu plating solution) Tin methanesulfonate (for Sn 2+ ): 50 g/L Copper methanesulfonate (for Cu 2+ ): 0.3 g/L methanesulfonic acid (for free acid): 150 g/L sulfide compound (n=2): 5 g/L nonionic surfactant: 5 g/L ion-exchanged water: residual part [0057] <Example 5> methanesulfonic acid to be used as free acid 1. A sulfide compound of general formula (1) with n=1 used as a complexing agent is mixed with a nonionic surfactant (a product obtained by adding 20 moles of polyoxyethylene to bisphenol A1 mole) After dissolving in tin methanesulfonate aqueous solution, add sodium gluconate as a complexing agent for tin and mercaptotetrazole, and then mix benzylidene acetone as a glossing agent. Thereafter, silver methanesulfonate solution was added and mixed. Finally, ion-exchanged water was added to make a bath of SnAg plating solution of the following composition. [Composition of SnAg plating solution] Tin methanesulfonate (for Sn 2+ ): 80 g/L silver methanesulfonate (for Ag + ): 1.0 g/L methanesulfonic acid (for free acid): 100 g/L sulfide compound (n=1): 3 g/L nonionic surfactant: 8 g/L sodium gluconate: 10 g/L mercaptotetrazole: 1 g/L benzylidene acetone: 0.01 mg /L Ion-exchanged water: residual part [0059] <Comparative Example 1> A SnAg plating solution was bathed in the same manner as in Example 1, except that the complex compound agent system used a sulfide compound of n=0 in general formula (1). [Comparative Example 2] The SnAg plating solution was bathed in the same manner as in Example 1, except that the complex compound agent used a sulfide compound of n=4 in general formula (1). [Comparative Example 3] The SnAg plating solution was bathed in the same manner as in Example 1, except that 3,6-dithio-1,8-octanediol was used as the complexing agent system. [Comparative Example 4] The SnAg plating solution was bathed in the same manner as in Example 5, except that the complex compound was a sulfide compound of n=4 in general formula (1). [0063] <Comparative Test and Evaluation> Using nine types of plating solutions after bathing in Examples 1 to 5 and Comparative Examples 1 to 4, the stability and plating performance of the tin alloy plating solution were evaluated. The stability of the tin alloy plating solution is evaluated by conducting an electrolytic stability test and a time-dependent stability test. The plating performance was evaluated by performing a thin-cell battery test and a plating test. [0064] (a) Electrolytic stability test. Nine kinds of tin alloy plating solutions after bathing were used as electrolytes, and a copper plate as a cathode and a platinum plate as an anode were placed in this electrolyte at a bath temperature of 25°C, Cathode current density of 10ASD each electrolyzed nine kinds of tin alloy plating solutions after bathing. Electrolytic plating consumes metal components in the plating solution, so 5 Ah/L of electrolytic plating is used to mix, dissolve stannous oxide (SnO) and silver oxide (Ag 2 O) powders to replenish the metal components Apply the bath and perform electrolytic plating to 200 Ah/L at the same time. After electrolytic plating, the concentration of the sulfide compound for the complex compound remaining in the tin alloy plating solution was quantitatively analyzed by the following HPLC (High Performance Liquid Chromatography) method. After filtering the tin alloy plating solution with a disposable syringe, an HPLC apparatus (model Prominence) manufactured by Shimadzu Corporation was used, and MeOH (methanol) was used as the mobile phase, and analysis was performed using L-ColumnODS kept at 40°C. Taking the current concentration of the complexing agent in the bath as 100%, the residual ratio (%) of the complexing agent after electrolytic plating is evaluated as the residual amount of the complexing agent. [0065] (b) Time-dependent stability test Each of the nine tin alloy plating solutions after bathing was placed in a glass sealed bottle and stored in a sterile oven made by Panasonic at 50°C for 6 months. Use the ICP luminescence analysis device (ICP-AES, model ICPE-9800) manufactured by Shimadzu Corporation, each with a metal concentration other than Sn in the current tin alloy plating solution in the bath, that is, the Ag concentration and SnCu in the SnAg alloy plating solution The Cu concentration in the plating solution is 100%, and the metal concentration other than Sn remaining after 6 months of storage is measured, that is, each of the remaining ratios of the Ag concentration in the SnAg alloy plating solution and the Cu concentration in the SnCu plating solution (% ). [0066] (c) Thin-film battery test After each of the nine types of tin alloy plating solutions after bathing was placed in a thin-film battery tank made by Yamamoto Gold Plating Tester Co., each of them used a copper thin-film battery plate as a cathode and a platinum plate as an anode Dispose in liquid, and conduct thin-film battery test. The plating conditions are: liquid temperature 25°C, energizing current 3A, and plating treatment time 5 minutes. During the plating process, the plating solution is stirred with a cathode rocker. When evaluating the thin-film battery, the current density chart plate was used to visually confirm the appearance of the coating film on the thin-film battery plate after the plating process, and then the glossy and semi-gloss coating film was regarded as "good", which was dull and turbid. The film is regarded as "possible", and the burnt film and burned film are regarded as "bad" for evaluation. [0067] (d) Electroplating test Each of the nine types of tin alloy plating solutions after bathing was used as an electrolyte to perform an electroplating test. After adjusting the liquid temperature of the electrolytic solution to 25° C., a copper substrate (length 10 cm, width 10 cm, thickness 0.3 mm) was immersed in the electrolyte, and the current density was 5 A/dm 2 for 10 minutes. The film thickness of 10 parts of the obtained plating film was measured using a fluorescent X-ray film thickness measuring device (manufactured by Hitachi High-Technologies Corporation). The maximum value (T max ), minimum value (T min ) and average value (T average ) of the film thickness at 10 locations are obtained, and then the film thickness uniformity is calculated by the following formula (2) to evaluate whether the plating can be uniformly performed. The above test results are shown in Table 1. Film thickness uniformity=(T max -T min )/(2×T average )×100(%) (2) [0068] [0069] It is known from Table 1 that Examples 1 to 5 using the sulfide compound represented by n=0 to 3 in the general formula (1) are that after electrolytic plating, the SnAg plating solution is 90% to 95%, The SnCu plating solution will have a high proportion of 88% of the complex compound, and the residual rate of Ag or Cu in the solution after being left over time is also high. The SnAg plating solution is 84%~97%, SnCu plating The coating solution is 89%. At the same time, the appearance of the coating is good in the plating performance, and the uniformity of the film thickness is also good. The SnAg plating solution is 2.1%~4.2%, and the SnCu plating solution is 3.2%. In addition, although Comparative Example 1 has good electrolytic stability and plating performance, it will reduce the residual rate of Ag over time. This is because the compound with n=0 used in Comparative Example 1 has one S atom in one molecule, and therefore has insufficient compounding ability with Ag ions, so it is presumed that Ag will be reduced and precipitated. In addition, Comparative Examples 2 and 4 have good plating solution stability, but poor plating performance. The reason is that the compound with n=4 has a high drainage property and a strong adsorption force with respect to the electrode surface, so it is presumed that it will hinder the smoothing effect of the surfactant used in combination. In addition, although Comparative Example 3 has good plating performance, since the tin alloy plating solution does not contain the sulfide compound of the present invention used as a complexing agent, the concentration of the complexing agent after electrolytic plating is low. INDUSTRIAL APPLICABILITY [0070] The plating solution of the present invention is suitable for forming electronic components such as semiconductor wafers and bump electrodes of printed circuit boards.
