Cracking of sintered silver layer always leads to the reliability issues in power devices. In this paper, the cracking behaviors of sintered silver layer have been investigated through numerical analysis with fracture based method. Energy release rate of various interfacial cracks and vertical cracks in sintered silver are computed. It is found that the energy release rate of interfacial crack and vertical crack are significantly influenced by their thickness. The thinner of the sintered silver layer, the higher of the energy release rate it will meet. For interfacial crack, the adding of the metallization layer does not improve the energy release rate significantly. For vertical crack, two conditions are considered, i.e., vertical crack emanating from the chip sider or emanating from the copper baseplate side, and it is found that the energy release rate is strongly dependent on its location and the existence of metallization layer. The increase of the thickness of Ni layer enables to lower down the entire level of energy release rate for vertical crack. Otherwise, the energy release rate of vertical crack near the edge region of the sintered silver layer is much higher than other locations. It implies that the cracking risk is higher for thinner sintered silver layer around the edge region which should be avoided. It is also found that the porosity effect on interface cracking and vertical cracking of sintered silver is also important.

烧结银层的开裂总是导致功率器件的可靠性问题。在本文中，通过基于断裂方法的数值分析研究了烧结银层的开裂行为。计算了烧结银中各种界面裂纹和垂直裂纹的能量释放率。发现界面裂纹和垂直裂纹的能量释放速率受其厚度的显着影响。烧结银层越薄，其能量释放率就越高。对于界面裂纹，金属化层的加入并没有显着提高能量释放率。对于垂直裂纹，考虑两种情况，即从芯片侧发出的垂直裂纹或从铜基板侧发出的垂直裂纹，并且发现能量释放速率强烈依赖于它的位置和金属化层的存在。Ni层厚度的增加能够降低垂直裂纹的能量释放率的整体水平。否则，烧结银层边缘区域附近的垂直裂纹的能量释放率远高于其他位置。这意味着应该避免的边缘区域周围较薄的烧结银层开裂风险更高。还发现孔隙率对烧结银界面开裂和垂直开裂的影响也很重要。否则，烧结银层边缘区域附近的垂直裂纹的能量释放率远高于其他位置。这意味着应该避免的边缘区域周围较薄的烧结银层的开裂风险更高。还发现孔隙率对烧结银界面开裂和垂直开裂的影响也很重要。否则，烧结银层边缘区域附近的垂直裂纹的能量释放率远高于其他位置。这意味着应该避免的边缘区域周围较薄的烧结银层的开裂风险更高。还发现孔隙率对烧结银界面开裂和垂直开裂的影响也很重要。