CdZnTe表面处理对其引线超声焊接质量的影响

Influence of Surface Treatment Technology on the Ultrasonic Welding Property Between the Down-lead and Au Electrode of CdZnTe Wafer

采用扫描电镜及EDS测试研究了高电阻CdZnTe金电极与外引线的超声焊接工艺,探讨了CdZnTe表面处理工艺、接触电极厚度及焊接参数对引线超声焊接质量的影响规律。研究结果表明,经机械抛光表面处理的CdZnTe晶片,其金电极与外引线间容易实现超声焊接;CdZnTe电极厚度与引线焊合率之间呈抛物线关系,获得最佳焊接质量的电极厚度为180nm左右。楔入压力和焊接功率是影响CZT金电极与引线焊接质量的重要因素,当焊接功率为2W、焊接压力为60×10-3kg、焊接时间20ms和烧球强度1.5W时,易获得良好的CdZnTe金电极与引线焊接接头。

By means of scanning electron microscope and EDS test, the factors which have a great influence on the ultrasonic wire bonding between the CdZnTe（CZT） electrode and the Au down-lead are studied, such as surface treatment technology, electrode thickness of CZT wafer and ultrasonic welding parameters. The results show that CZT wafer with the mechanical polishing treatment was easier to achieve the ultrasonic wire bonding between the Au electrode of CZT and the down-lead. Moreover, the weldbility between the CZT electrode thickness and the down-lead shows a kind of parabola relationship. That＇s to say, there should be an optimal CZT electrode thickness （180nm in this research） for the high bonding rate when the electrode treatment technology had been fixed up. Besides, the welding power and the wedge pressure influence the ultrasonic wire bonding rate greatly. In this test, the optimal welding parameters were as follows： the power 2W, the pressure 60X 10^-3kg, welding time 20ms and the power for fire ball formation 1.5W.