添加剂对四羟丙基乙二胺-乙二胺四乙酸二钠体系化学镀厚铜的影响  

Influences of Additives on Electroless Copper Plating in Tetrahydroxypropyl Ethylenediamine-Disodium Ethylene Diamine Tetraacetic Acetate Bath

作　　者：曹权根 陈世荣[1] 杨琼[1] 汪浩[1] 谢金平 范小玲 

机构地区：[1]广东工业大学轻化学院,广东广州510006 [2]广东致卓精密金属科技有限公司,广东佛山528247

出　　处：《材料保护》2015年第1期5-8,20,共5页Materials Protection

摘　　要：为解决目前四羟丙基乙二胺(THPED)-EDTA·2Na盐化学镀铜体系存在的镀速慢、稳定性不佳等问题,重点考察了不同添加剂对THPED-EDTA·2Na盐化学镀铜的影响。结果表明:硫脲(>3 mg/L)、2-巯基苯并噻唑(2-MBT)和有机物M(含巯基的咪唑类化合物)对镀液的稳定效果较好;硫脲会极大地降低沉积速率,且镀层较差;2-MBT可以提高沉积速率,但稳定镀液的能力有限;有机物M兼有加速剂、稳定剂和光亮剂的功能,对镀液的稳定效果最好,且镀层光亮细致;吐温-80和亚铁氰化钾均能改善镀层外观质量,但对沉积速率及镀液稳定性的影响不大;通过正交试验,以有机物M与2-MBT,吐温-80和亚铁氰化钾复配,确定了最优复合添加剂配方:2-MBT 7mg/L,有机物M 20 mg/L,亚铁氰化钾10 mg/L,吐温-80 20 mg/L;在适宜工艺条件(温度40℃,p H值12.5)下,镀速达到16.3μm/h,镀液稳定时间可达146 min,所得镀层平整、光亮、细致,沉积层为立方晶系铜,PCB孔覆背光级数达到9级,满足PCB工业生产要求。Influences of several additives on the electroless Cu plating in tetrahydroxypropyl ethylenediamine-disodium ethylene diamine tetraacetic acetate(denoted as THPED-EDTA·2Na) bath were investigated for the purpose of getting rid of slow plating rate and poor bath stability.The composition of the plating bath and the electroless plating condition were optimized based on orthogonal tests.Results indicated that additives thiourea(>3 mg/L),2- mercapto benzothiazole(denoted as 2-MBT) and organic compound M(imidazole compound containing mercapto) were capable of effectively improving the stability of the plating bath.Namely,thiourea led to greatly reduced plating rate and provided Cu coating with poor appearance quality.Additive 2-MBT could increase the plating rate but had limited ability to increase the stability of the plating bath.Organic compound M simultaneously functioned as the accelerating agent,stabilizing agent and brightener,and it had the best ability to increase the stability of plating bath,providing bright and fine Cu coating.Moreover,both Tween-80 and K_4Fe(CN)_6could significantly improve the appearance quality of the Cu coating,but they had slight influence on the plating rate and plating bath stability.In the presence of organic compound M,2-MBT,Tween-80 and K_4Fe(CN)_6 as the compounded additives,their optimized formulation was suggested as 7 mg/L 2-MBT,20 mg/L organic compound M,10 mg/L K_4Fe(CN)_6,and 20 mg/L Tween-80;and the optimal plating condition was suggested as a temperature of 40℃ and a bath pH value of 12.5.Under the optimized electroless plating condition,the plating rate of Cu was as much as 16.3 μm/h,and the plating bath retained good stability up to a duration of 146 min.Resultant Cu coating,composed of cubic Cu,was smooth,bright,and fine;and its backlight level achieved 9th grade,meeting with the requirement for industrial production of printed circuit board.

关 键 词：化学镀厚铜 添加剂 四羟丙基乙二胺(THPED)-EDTA·2Na体系 沉积速率 稳定性 镀层质量 

分 类 号：TG174.4[金属学及工艺—金属表面处理]