3D-IC类同轴屏蔽型TSV的热力响应分析及结构优化

Thermal-Mechanical Response Analysis and Structure Optimization of Coaxial-Like Shielded TSV in 3D-IC

硅通孔(TSV)是解决三维集成电路(3D-IC)互连延迟问题的关键技术之一。TSV内部结构的变形失效,大多是由循环温度载荷产生的交变应力引起的。从信号完整性角度考虑,建立了接地TSV形状分别为圆柱形和椭圆柱形的类同轴屏蔽型TSV模型。基于最大Mises应力准则,对比分析了循环温度载荷对2种类同轴屏蔽型TSV热应力-应变的影响及最大应力点的主要失效形式。最后综合考虑TSV的几何参数对导体和凸块危险点Mises应力的影响,对椭圆柱形类同轴屏蔽型TSV结构进行多目标优化,将2种最优结构中2个危险点的Mises应力分别降低15.10%、17.18%和18.89%、6.74%。为提高TSV热可靠性的优化设计提供参考。

Through silicon via(TSV) is considered to be one of the key technologies to solve the problem of delay of three-dimensional integrated circuit(3D-IC) interconnection.The deformation failure of TSVs is mostly caused by the alternating stress generated by the cyclic temperature load.From the aspect of the signal integrity,coaxial-like shielded TSV models with cylinder and elliptic cylinder ground TSVs were established respectively.Based on the maximum Mises stress criterion,the effect of the cyclic temperature load on the thermal stress-strain of two types of coaxial-like shielded TSV were compared and analyzed,and the main failure forms of the maximum stress points were analyzed.Finally,the effect of TSV geometrical parameters on the Mises stress of dangerous points in conductors and bumps were considered comprehensively,and the multi-objective optimization of elliptical coaxial-like shielded TSV were carried out.The Mises stress of the two dangerous points in two optimal structures is reduced by 15.10%,17.18%,18.89%,6.74%,respectively,which can provide reference for the optimal design of improving the thermal reliability of TSVs.