Fe-Ni新型UBM薄膜的晶圆电镀工艺研究

WAFER LEVEL ELECTRODEPOSION OF Fe-Ni NOVEL UBM FILMS

利用改良型硫酸盐-氯化物镀液体系,进行了晶圆级Fe-Ni凸点下金属层(UBM)电镀工艺的开发研究.研究了镀液中Fe^(2+)含量、电镀温度及电流密度对镀层成分的影响规律,得到了特定工艺条件下镀层成分控制的完整曲线;测量了不同电镀时间和不同电流密度下的镀层生长速率,为实际生产中控制UBM镀层的厚度提供了依据;利用XRD和TEM对镀层的晶体结构及微观形貌进行了表征;利用滴定、等离子体发射光谱(ICP)等手段,对镀液在生产及静置条件下主盐离子浓度的变化趋势进行了监测,测定了抗坏血酸在镀液体系中与Fe^(3+)的反应能力,提出了镀液的日常维护、保存、调控方案以及:Fe^(3+)的抑制方案.

Using customized wafer electroplating system, the electrodeposition process of Fe-Ni under bump metallization （UBM） thin film has been developed by modified Watts bath. The major factors which can affect the Fe content in the final UBM films, including the concentration of Fe^2＋, electrodeposition temperature and current density, were investigated systematically. The growth rate of Fe-Ni film under different electroplating conditions was measured in order to provide a reference for actual production. The microstructure and morphology of obtained Fe-Ni films were characterized by XRD and TEM. Multiple kinds of analytical methods including titration and inductive coupled plasma emission spectrometer （ICP） were used to monitor the content change of bath component under working or storage conditions. Regulations were put forward to maintain the bath daily including the keeping of the main salt content and the inhibition of Fe^3＋ concentration.