基于恒电流法晶圆电镀金的工艺研究

Technological Study of Suffite Gold Electroplating by Constant Current Elelctrodepostion on a Wafer

介绍了采用亚硫酸盐镀金工艺在晶圆上镀金膜的工艺流程,以及电镀液的日常维护和基于恒电流法电镀金的工艺影响因素。对亚硫酸镀金工艺进行了优化,确定了最佳的工艺参数:金10 g/L,亚硫酸钠140 g/L,磷酸氢二钾40 g/L,柠檬酸钾80 g/L,氯化钾100 g/L,EDTA-2Na 10 g/L,十二烷基硫酸钠0.01~0.2 g/L,光亮剂20 g/L,pH值7.5~8.0,阴极电流密度2.1 m A/cm^(2),阳极Pt网,磁力搅拌转速200转/min,电镀液温度为45℃。成功地得到了光滑细致的金黄色镀层。采用扫描电镜(SEM)和能谱成分分析(EDS)对电镀金膜的表面形貌、成分进行了分析,结果表明,电镀金膜表面晶粒均匀、致密,金膜的纯度也极高。解决了激光器芯片中要求电参数性能长期稳定的表面电极的镀金膜问题。

The suffite gold electroplating process on silicon wafer is described in the paper.The maintenance of electroplating and affecting factors of constant current electroplating gold are also described.The suffite gold plating process is optimized and the process parameters are determined.The most optimal parameters:Gold is 10 g/L,sodium sulfite is 140 g/L,potassium dihydrogen phosphate is 40 g/L,potassium citrate is 80 g/L,potassium chloride is 100 g/L,EDTA-2Na is 10 g/L,sodium dodecyl sulfate is 0.01~0.2 g/L,brightener is 20 g/L,pH is 7.5~8.0,cathode current density is 2.1 mA/cm^(2),anode is platinum mesh,magnetic strirring speed is 200 RPM,and the temperature of electroplating solution is 45℃.The obtained films are brightly golden yellow.The morphology and composition of the electroplating gold film under the optimal conditions are analyzed by the SEM and EDS techniques.The results show that the micro-morphology of the gold film is smooth and dense,and the purity of the gold film is very high.The research objective is to solve the problem of electroplating gold on surface electrode,which requires stable performance of electric parameters on laser wafer in the long term.