Design and fabrication of Cu-TSV free-standing specimen for uniaxial micro-tensile test

A novel test sample with a micro scale free-standing specimen of Cu-TSV used for uniaxial micro-tensile test is presented in this paper. Design of a deformation-buffer reticular supporting frame of the test sample effectively reduces the deformation of Cu-TSV thin film during clamping operation. The stress resulting from electrodepositon process is minimized by fabricating Cu-TSV thin film on surface-treated titanium seed layer. The process of titanium seed layer avoids alkali corrosion and simplifies fabrication procedure compared with that of the traditional Cr/Cu seed layer. Both finite-element method (FEM) simulation and experimental results indicates the advantages of this new design. The test sample fabricated by the optimized process well coordinates with our micro-tensile system. The Young's modulus and the ultimate tensile strength of tested Cu-TSV thin film measured by our micro-tensile system are 25.4~32.9GPa and 574~764MPa, respectively.