Effect of temperature cycling on the leakage mechanism of TSV liner

Abstract

The temperature cycling tests of 0, 100 and 300 cycles were carried out on the double blind TSV samples, and the TSV liner microstructure, I-V and CV of the temperature cycled samples were tested. The failure mechanism of TSV liner during temperature cycling was clarified. Combined with microstructure observation, the process of TSV liner SiO2 degradation caused by temperature cycling was studied. The result shows that, with the increasing cycles from 0 to 100 and 300, the morphology of TSV liner gradually getting defective with exhibition of microcracks and microvoids initiation along sidewall interface compared to the 0-cycled TSV samples. With further increasing of cycles to 300, the interfacial penetrating cracks occurred within sidewall interface. This microstructure evolution are directly relative to transition of its failure mechanism. The failure mechanism is dominated by the Schottky emission leakage for the 0-cycled and 100-cycled TSV samples, which will translate to the mechanical cracking with the generation of penetration cracking along the TSV liner for the 300-cycled TSV samples. Moreover, the defect density in the positively charged SiO2 layer at the TSV liner increased by 120 % before and after 100 temperature cycles. These defects are caused by the severe degradation of SiO2 layer introduced by 100 temperature cycles.