应用化学镀的DPC陶瓷基板制备技术研究

发布时间：2018-05-28 21:06

  本文选题：DPC + 化学镀铜　； 参考：《华中科技大学》2015年硕士论文

【摘要】：随着芯片功率的不断提高,面积不断缩小,集成度越来越高,LED封装对散热基板提出了更高要求。直接电镀陶瓷基板(Direct plated copper,DPC)是在陶瓷基片上采用薄膜工艺制作完成的,其化学性质稳定、热导率高、线路精细、热膨胀系数(CTE)与芯片材料相匹配,因此成为大功率LED封装散热基板的重要发展方向。然而目前DPC基板由于价格偏高,没有相应的质量和测试标准,限制了其在大功率LED封装中的应用。本论文采用陶瓷表面化学镀铜作为DPC基板种子层,减少了磁控溅射等高成本设备和工艺,降低了DPC基板制作成本;采用脉冲电镀代替直流电镀增厚铜层线路,不仅提高了效率,同时优化了镀层质量;电镀银层取代金层作为焊接层和保护层,降低材料成本;通过与其他类型陶瓷基板对比,提出了一些关于DPC基板性能的测试方法,为进一步规范DPC基板质量标准进行了探索。本文研究工作围绕降低DPC基板成本,提高基板性能展开,主要研究内容包括:首先,利用甲醛还原镀铜体系在陶瓷基体上沉积化学镀铜层,完成DPC基板种子层制作。采用正交实验、单因素分析等方法优化镀液参数,得到化学镀铜的最佳工艺参数:硫酸铜浓度为8g/L、酒石酸钾钠浓度为40g/L、甲醛浓度为10g/L,温度35℃,时间30min;采用百格法、微观形貌、成分分析、高低温循环等多种测试手段综合分析化学镀铜层的性能,结果表明化学镀铜层具备较好的电学和机械性能;其次,考察分析了脉冲镀铜电流密度与电镀速率的关系,结果表明在一定范围内,两者成正比关系。相同电流密度下,相比于直流电镀,脉冲电镀可以明显减少瘤状结构的产生,优化镀层质量;采用3ASD的电流密度,不仅提高电镀效率,而且可以得到形貌良好的线路层;再次,银是相对便宜的贵金属,采用硫代硫酸盐镀银体系分别在铜层和镍层上电镀银层,对比分析这两者的性能,结果表明,镍层上的镀银层具有更好的结合强度和耐高温性,并且电流密度为0.2ASD时,银层结合力较好;最后,提出了测试陶瓷基板热阻较为准确的方法,通过模型对比,减少了主观误差,提高了测试精度;提出了一种测试陶瓷基板润湿性的简单比较方案;最后结合表面粗糙度、热冲击等测试手段,对比分析DPC与其他陶瓷基板的性能,结果表明DPC基板具有较好的综合性能。
[Abstract]:With the continuous improvement of chip power and the continuous reduction of the area, the higher integration of LED packaging put forward higher requirements for the heat dissipation substrate. Direct plated copper DPCs are fabricated on ceramic substrates by using thin film technology. Their chemical properties are stable, thermal conductivity is high, the circuit is fine, and the coefficient of thermal expansion (CTE) matches the material of the chip. Therefore, it has become an important development direction of high power LED packaging heat dissipation substrate. However, the application of DPC substrate in high power LED packaging is limited due to its high price and lack of corresponding quality and test standards. In this paper, electroless copper plating on ceramic surface is used as seed layer of DPC substrate, which reduces high cost equipment and process such as magnetron sputtering, and reduces the cost of making DPC substrate. At the same time, the quality of the coating was optimized, the electroplated silver layer replaced the gold layer as the welding layer and the protective layer to reduce the material cost, and by comparing with other types of ceramic substrates, some testing methods about the properties of the DPC substrate were put forward. In order to further standardize the DPC substrate quality standards were explored. This paper focuses on reducing the cost of DPC substrate and improving the performance of the substrate. The main research contents are as follows: firstly, electroless copper coating was deposited on ceramic substrate by formaldehyde reduction copper plating system, and the seed layer of DPC substrate was made. The optimum technological parameters of electroless copper plating were obtained by orthogonal experiment and single factor analysis. The optimum parameters were copper sulfate concentration of 8g / L, potassium sodium tartrate concentration of 40g / L, formaldehyde concentration of 10g / L, temperature of 35 鈩，

本文编号：1948187