电镀镍磷层及其在薄膜剥离中的应用

Electroplated Nickel-Phosphorus Layer and Its Application in Film Stripping

利用柔性压电薄膜为能量采集器供电在微电子机械系统（MEMS）领域应用越来越广泛,通过电镀应力层剥离制备薄膜是近年来广受关注的一种方法。通过在氯化镍电镀液中加入不同质量浓度的磷离子和控制不同的电流密度,在铜片上电镀得到不同的镍磷镀层。对镀层进行共聚焦显微镜观测、台阶仪测量厚度、镍磷层内应力计算、X射线衍射（XRD）和X射线能谱仪（EDS）分析,结果表明：电流密度恒定为10 mA/cm2,磷离子质量浓度由0-0.04 g/L的变化过程中,镍磷层内应力由112 MPa增加到322 MPa,而磷离子质量浓度高于0.04 g/L后,内应力减小,镀层含磷原子数分数逐渐升高;磷离子质量浓度恒定为0.04 g/L,电流密度由5 mA/cm2增加到20 mA/cm2时,镍磷层内应力从181 MPa增加到343 MPa,而电流密度高于20 mA/cm2后,内应力逐渐减小,镀层含磷原子数分数逐渐降低。之后通过控制电镀条件利用电镀镍磷层应力从硅基底成功剥离制备硅薄膜。

Using flexible piezoelectric films to power energy collectors is more and more widely applied in the field of micro-electromechanical systems（MEMS）.The method for stripping and preparing a thin film by electroplating stress layer has drawn extensive attention in recent years.The electroplated nickel-phosphorus layers on the copper plates were gotten by adding different mass concentrations of phosphorus ions to the nickel chloride electroplating solution and controlling different current densities.The observation of the confocal microscopy,thickness measurement by the step profiler,calculation of the internal stress of the Ni-P layer,analyses of X-ray diffraction（XRD）and X-ray energy dispersive spectroscopy（EDS）were used to obtain the parameters of electroplated coatings.The results show that when the current density is constant at10 mA/cm2 and the mass concentration of the phosphorus ion varies from0 to 0.04 g/L,the internal stress of the Ni-P layer increases from112 MPa to 322 MPa.While the mass concentration of the phosphorus ion is higher than 0.04 g/L,the internal stress decreases and the atomic number fraction of phosphorus in the electroplated coating gradually increases.When the mass concentration of phosphorus ion is constant at 0.04 g/L and the current density increases from5 mA/cm2 to 20 mA/cm2,the internal stress of the Ni-P layer increases from 181 MPa to343 MPa.While the current density is higher than 20 mA/cm2,the internal stress gradually decreases and the atomic number fraction of phosphorus in the Ni-P layer gradually reduces.Then the silicon films were successfully stripped from the silicon substrate using the stress of the electroplated Ni-P layer by controlling electroplating conditions.