LTCC电路基板金层表面斑点问题研究

Research on the Surface Spots on the Gold Layer of LTCC Circuit Substrates

针对LTCC电路基板金层表面斑点问题开展研究,观察了LTCC电路基板表面斑点显微形貌,对斑点组成成分进行定性分析,推断出LTCC电路基板表面斑点形成的原因。分别采用化学清洗和重烧法去除基板表面斑点,对比了两种方法的实验结果,确定了一种去除斑点的有效方法。实验结果表明:LTCC电路基板金层表面红色斑点组成成分为Ag2S,采用重烧法可以消除表面斑点,不损害基板性能,斑点消除区金层金丝键合强度没有减弱并满足国军标使用要求。建议通过加强印刷、烧结环节过程把控,以及采用真空或氮气密封LTCC基板的方式,有效减少金层斑点的形成。

In the paper, the surface spots on the gold layer of LTCC substrates were studied deeply. The microtopography and composition of the surface spots was analyzed by scanning electron microscope and energy dispersive spectrometer respectively. The reason why the surface spots were formed on the gold layer of LTCC substrates was concluded reasonably. Both of chemical reagents and retiring method were employed to eliminate the surface spots so as to find out the effective solution. The result was shown that the red color spots were composed of Ag2S which can be wiped out effectively by retiring rather than chemical method. The gold bond strength of the cleaned area wasn＇t weakened and met the requirements of the military standard. In order to avoid the formation of spots, it was advised to strengthen the control of printing and sintering process and protect the LTCC substrates by vacuum or nitrogen seal.