新型次磷酸钠体系化学镀铜添加剂及其对镀液和镀层性能的影响

目的将聚乙烯吡咯烷酮和二苯胺磺酸钠作为添加剂应用到次磷酸钠化学镀铜体系,并获取最佳应用效果的工艺和条件。方法以PCB环氧树脂板为基材,通过电化学方法研究以聚乙烯吡咯烷酮和二苯胺磺酸钠为添加剂的次磷酸钠体系化学镀铜液及其性能,用称量法研究添加剂对沉积速率的影响,用扫描电镜和X射线能谱仪分析添加剂对沉铜表面质量的影响,用极化曲线法研究添加剂对沉铜表面孔隙率的影响,用交流阻抗法研究添加剂对沉铜表面耐蚀性的影响,同时测定镀液的稳定性。结果在p H=10、温度为65℃的基础液(成分为5 g/L五水硫酸铜、30 g/L次磷酸钠、16 g/L柠檬酸钠、30 g/L硼酸、1 g/L硫酸镍)中,单独加入聚乙烯吡咯烷酮或二苯胺磺酸钠,都能起到很好的沉铜效果。它们的最佳质量浓度分别为20~28mg/L和50~58mg/L。当聚乙烯吡咯烷酮和二苯胺磺酸钠在最佳范围内组合使用时,获得的镀液更稳定,镀层孔隙率低、耐蚀性好、表面均匀,表面铜的质量分数达到95.52%,镀层显粉红色,沉积速率在1.5~2.5μm/h范围内,符合PCB行业要求。结论最佳的化学镀铜液配方和条件为:5 g/L五水硫酸铜、30 g/L次磷酸钠、16 g/L柠檬酸钠、30 g/L硼酸、1 g/L硫酸镍、20~28 mg/L聚乙烯吡咯烷酮、50~58 mg/L二苯胺磺酸钠,pH=10,温度65℃。研究成果对电镀铜添加剂的开发和应用有重要意义。

Novel Electroless Plating Copper Additives for Sodium Hypophosphite System and Its Effect on the Properties of Plating Bath and Coating

The work aims to apply polyvinyl pyrrolidone and diphenylaminesulfonic acid sodium to the electroless copper plating system of sodium hypophosphite as additives,and to obtain the process and condition of the optimum application results.Based on PCB epoxy resin board,the electroless copper plating system of sodium hypophosphite with polyvinyl pyrrolidone and diphenylaminesulfonic acid sodium as additives and its performance were investigated by the electrochemical method.The effect of additives on deposition rate was studied by heavy method;the effect of additives on the surface quality was analyzed by SEM and EDS;the effect of additives on the surface porosity was studied by the polarization curve method;the effect of additives on the corrosion resistance was studied by AC impedance;and the stability of plating solution was also measured.The results show that,when pH=10 and at 65℃,both polyvinyl pyrrolidone and diphenylaminesulfonic acid sodium had good properties for electroless copper deposition in base solution including CuSO45 g/L,NaH2PO230 g/L,Na3C6H5O7·2H2O 16 g/L,H3BO330 g/L,NiSO41 g/L,and their best dosages were 20~28 mg/L and 50~58 mg/L respectively.When used polyvinyl pyrrolidone and diphenylaminesulfonic acid sodium as combined additive in the range of their best dosage,the plating solution was more stable,the porosity of the coating was low,the corrosion resistance was good,the surface was uniform,and the copper content on the surface was up to 95.52%.Furthermore,the coating was pink and the deposition rate was in the range of 1.5~2.5μm/h,which all met the requirements of PCB industry.Therefore,the best novel electroless copper deposition solution are that,CuSO45 g/L,NaH2PO230 g/L,Na3C6H5O7·2H2O 16 g/L,H3BO330 g/L,NiSO41 g/L,polyvinyl pyrrolidone 20~28 mg/L,diphenylaminesulfonic acid sodium 50~58 mg/L when pH=10 and at 65℃.The research results are of great significance to the development and application of electroless copper deposition additives.