为得到硅通孔电镀填充铜(TSV-Cu)的力学性能, 对TSV-Cu进行了Berkovich纳米压痕实验. 基于Oliver-Pharr算法和连续刚度法确定TSV-Cu的弹性模量和硬度分别为155.47 GPa和2.47 GPa; 采用有限元数值模拟对纳米压痕加载过程进行反演分析, 通过对比最大模拟载荷与最大实验载荷, 确定TSV-Cu的特征应力和特征应变; 由量纲函数确定的应变强化指数为0.4892; 将上述实验结果代入幂强化模型中, 确定TSV-Cu的屈服强度为47.91 MPa. 最终确定了TSV-Cu的幂函数型弹塑性应力-应变关系.

In 3D electronic package technologies, through silicon via (TSV) plays a critical important role. TSVs are usually fully filled by electroplating copper, namely TSV-Cu, which has very different mechanical properties from bulk copper. To obtain the mechanical properties of the TSV-Cu, the Berkovich nanoindentation tests were conducted, and the Oliver-Pharr algorithm and the continuous stiffness measurement method were used to acquire the elastic modulus and hardness. Then finite element modeling (FEM) simulations are adopted for reverse analysis of the nanoindentation loading process to determine the representative stress and strain of the TSV-Cu by comparing the maximum value of simulated load to that of experimental load. The strain hardening exponent of the TSV-Cu is determined by dimension functions. The yield strength of the TSV-Cu is acquired by substituting the representative stress, the representative strain and the strain hardening exponent into a power law stress-strain constitution. Finally, a power law elastic-plastic stress-strain relationship of TSV-Cu is built. The obtained elastic modulus and hardness of the TSV-Cu are 155.47 GPa and 2.47 GPa, respectively; the strain hardening exponent is 0.4892 and the yield strength is 47.91 MPa.