超大面积芯片烧结技术研究

摘要

With the development of semiconductor power devices, chip’s cooling of the device was one of the factors which has been restricting the power devices’ development. The device’s cooling was mainly through the internal heat conduction out of the back of the chip. The chip welding heat from the device directly affect one of the key factors is good or bad, the obvious advantages of alloy solder’s thermal conductivity is good, therefore widely used in high power devices(such as Au80Sn20, Au99.4Sb0.6, etc), but as a result of alloy solder caused large residual stress after sintering, sintering process is less application on the chip size greater than 8 mm×8 mm. In the paper, 11.5 mm×11.5 mm large chip sintering experiment was carried out uses Au-Sn alloy, through the analysis of the causes of stress, from material, packaging process, etc, to take steps to reduce stress, and veriifed the reliability assessment of packaging products. The experimental results show that there is no chip failure.%随着半导体大功率器件的发展，芯片的散热一直是制约功率器件发展的因素之一。而器件内部散热主要是通过芯片背面向外传导，芯片焊接工艺是直接影响器件散热好坏的关键因素之一，合金焊料的一个显著优点就是其导热性能好，因此在散热要求高的大功率器件中使用较为广泛（如Au80Sn20、Au99.4Sb0.6等），但由于合金焊料烧结后会产生较大的残余应力，在尺寸大于8 mm×8 mm的芯片上，烧结工艺应用较少。文章针对11.5 mm×11.5 mm超大面积芯片进行金锡合金烧结试验，经过对应力产生的原因进行分析，从材料、封装工艺等方面采取措施来降低缓释应力，并对封装产品进行可靠性考核验证。试验结果表明，没有芯片存在裂纹、碎裂现象，产品通过了可靠性验证。