镀金体系Ni-P合金基体腐蚀机制与微互连可靠性关系研究

化学镀镍/置换镀金(ENIG)组合镀层存在的偶发性焊接失效是制约该技术在微电子产品表面应用的瓶颈问题。镀金时镍磷合金基体的腐蚀是焊接失效的重要原因，但常规方法很难直接研究镀金时镍磷基体的腐蚀情况。在前期较深入研究的基础上，本项目设计耐腐蚀性能不同的镍磷镀层和腐蚀能力不同的置换镀金液，通过电化学扫描探针显微镜、扫描电化学显微镜和现场表面增强拉曼光谱原位在线与电化学阻抗谱等电化学测试技术相结合，并用SEM、XRD、XRF等非在线的表面分析方法相辅助，研究置换镀金时镍磷合金基体的腐蚀机制，探讨ENIG镀层在微电子互连时的焊接特性，研究镍磷合金的腐蚀与焊接可靠性间的本质关系。为预防焊接失效，完善ENIG技术及提高ENIG镀层性能提供理论指导。课题的实施将明确置换镀金时镍磷合金基体的腐蚀机理，建立腐蚀-焊接失效的可靠性模型，有利于提升电化学与微电子领域的交叉学科理论水平。

The electroless nickel immersion gold (ENIG) process has been used as one of the best finishing methods for microelectronic products. Unfortunately, the usage of ENIG faces the bonding failure problems during the following soldering stage, which restricts the use of ENIG process. The corrosion of nickel-phosphorus (Ni-P) alloy during immersion gold process is the major factor leading to loss of solderability. However, it's difficult to to directly study the corrosion of Ni-P alloy subtrate during immersion gold using the conventional method. The Ni-P alloy with different P content and the immersion gold bath with different corrosion ability are designed on the basis of pre-research in this project. Electrochemical scanning probe microscopy, scanning electrochemical microscopy and surface-enhanced raman spectroscopy measurements are employed to in situ study the immersion gold plating process on electroless Ni-P alloy substrate. In addition, the study will be also performed by measuring the electrochemical impedance in combination with the surface analysis, such as SEM, XRD and XRF. The corrosion mechanism of Ni-P alloy substrate and the solderability of ENIG coating during microelectronic interconnect will be obtained. And then, the nature of the relationship between the corrosion properties and the sollderability can be determined. This will provide theoretical guidance for preventing soldering failure, improving the ENIG technology and the performance of coatings.The implementation of the project will obtain the corrosion mechanism of Ni-P alloy substrate and establish the corrosion-solder joint reliability prediction model, which can enhance the theoretical level in the interdisciplinary area of electrochemistry and microelectronics.