电镀铜薄膜力学性能的实验研究

电子器件中大量使用铜膜作为电信号通道,而且一般采用电镀工艺制成.铜膜的力学性能参数对于其热疲劳可靠性的研究非常重要.目前有关该材料的力学性能研究尚不充分,而且数据极为不统一.本文借助于纳米压痕法、声发射等实验手段对电镀铜薄膜的静态力学性能(包括弹性模量和屈服强度等)及疲劳性能进行了测试.结果发现,与大块铜材料相比,电镀铜薄膜的弹性模量低很多,但屈服强度与大块铜材料相当,甚至高出200％.同时,本文采用弯曲疲劳实验,以电阻变化为失效判据,对镀铜材料的疲劳性能进行了测试,获取了该材料不同失效判据下的疲劳寿命预测模型的系数.

Experimental Study of Mechanical Properties for Electroplated Copper Film

Copper film manufactured generally by electroplating process is extensively used as an electrical signal channel in various electronic devices. So its mechanical property is very important to thermal fatigue reliability. However, the study of its mechanical property is currently not so sufficient, and the obtained data are highly divergent. Static mechanical properties including elastic modulus, yield strength and fatigue property of electroplated copper film were tested based on nano-indentation and acoustic emission. Results show that Young's modulus of electroplated copper film is much lower than that of bulk copper, but the yield strength is approximately equal to that of bulk copper or even 200% higher. Besides the static data, fatigue behavior of electroplated copper film was also tested based on bending fatigue experiment. In experiment, the change of resistance rather than the load drop was selected as a failure criterion. The coefficients of fatigue life prediction model under different failure criterion were obtained.