Ni-Co合金+Au镀覆陶瓷外壳的引线键合可靠性研究

Wire Bonding Reliability Study of Plating Ni-Co and Au Layer Ceramic Package

为了提高陶瓷外壳镀层耐高温变色、耐腐蚀以及长期贮存的能力,带金属零件的陶瓷外壳需采用Co含量在20%~40%的Ni-Co+Au镀覆结构,镀层经退火处理。研究分析了Ni+Au镀覆和NiCo+Au镀覆结构对铝丝楔焊和金丝球焊可靠性的影响,通过常温、300℃高温贮存1 h、300℃高温贮存24 h后引线键合强度变化、键合面的元素面分布进行量化比较。试验表明Ni+Au和Ni-Co+Au镀覆结构对引线键合强度和可靠性无明显影响;两种镀覆结构的外壳在键合时,键合工艺参数也不需要进行较大的调整;铝丝在Ni-Co+Au镀覆结构与Ni+Au镀覆结构上键合,在键合界面均会生成金铝金属间化合物,但只要金层厚度受控,均不会产生"Kirkendall"失效,相对来讲Ni-Co+Au镀覆结构的缺陷密度较低,生成金铝金属间化合物进程会慢些。

In order to improve the anti-tarnish plating ceramic package ability, corrosion resistance and long-term storage capability, ceramic package with metal parts requires Ni-Co plating layer containing Co with in 40%mass of the layer and then can be used by the consumers after electroplating Au layer. The paper compareswire bonding intensity and element distribution under the temperature:room temperature, 300℃in one hour and 300℃in 24 hours. It analyzes the reliability influence of aluminum wire wedge bonds and the gold ball bonds processunder the condition:Ni+Au plating layer and Ni-Co+Au plating layer. The experiments indicate that Ni-Co and Ni-Au plating layer do no obvious effect on the reliance and the bond strength.Existing bonding process also does not need to make adjustments to meet the bond strength and bond interconnect reliability. Aluminum wire bonding in the Ni-Co+Au plating layer or the Ni+Au plating layer were generated between Au-Al intermetallic compounds in the bonding interface, but as long as the thickness of the gold layer is controlled, it will not produce"Kirkendall"failure, relatively speaking, a Ni-Co+Au plating layer is relatively low defect density, aluminum intermetallic compounds generated process will be slower.