离子注入对聚四氟乙烯覆铜板黏结性能的影响

Effect of ion implantation on bonding properties of PTFE copper clad laminate

  • 摘要: 对于聚四氟乙烯(PTFE)基材线路板,铜箔与基材的结合力是影响其可靠性的关键因素之一。纯PTFE表面与铜箔的黏结性能较差,可采用离子注入结合磁过滤沉积技术对PTFE进行改性处理,再电镀铜薄膜制备PTFE覆铜板。采用SEM和XPS分析改性PTFE的表面微结构及表面成分;使用达因测试笔测试其表面张力;利用SRIM软件模拟不同厚度过渡层对注入离子以及基体原子浓度随深度分布的影响;采用90°剥离强度测试仪分别测试液氮、热应力及浸锡环境下改性PTFE覆铜板的剥离强度;通过宽频介电阻抗谱仪研究其电导率及介质损耗性能。结果表明:改性处理后的PTFE表面形貌发生显著变化,可与铜箔形成有机结合的过渡层,所制得的柔性覆铜板性能良好、稳定,剥离强度明显提高——常温下为0.74 N/mm,在液氮、热应力及浸锡环境下剥离强度略有下降,电学性能符合电路板使用要求。

     

    Abstract: For the PTFE copper clad laminate, the peel strength between the copper foil and the substrate is one of the most critical factors for its reliability. To improve the bonding property of the pure PTFE, the base material is modified by the filtered magnetic deposition combined with the ion implantation technology, and then the PTFE copper clad laminate is prepared by electroplating. SEM and XPS are used to analyze the surface morphology, the microstructure, and the composition of the modified PTFE sample. The surface tension of the sample is determined using a Dyne test pen. The influence of different thickness transition layers on the implanted ions is simulated by the SRIM software, together with the changes of the atomic density with the matrix depth. In addition, the peel strength of the modified PTFE copper clad laminate is measured in the liquid nitrogen or thermal stress environment, using a 90° peel strength tester. The conductivity and dielectric loss properties are investigated by a broadband dielectric impedance spectrometer. The experimental results demonstrate that the surface morphology of the PTFE treated by the ion implantation has changed significantly, forming a transition layer of the copper foil and the PTFE organically combined. The bonding property of the PTFE copper clad laminate is improved with the peel strength rising to 0.74 N/mm. Though the peel strength decreases slightly in the liquid nitrogen, with the thermal stress or in the dip soldering environment, the electrical properties of the copper clad laminate can still meet the requirement.

     

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