Influence of Single/Double Sweeping Mode and Sweeping Voltage Increment/Polarity on Measurement of TSV Leakage Current

摘要

Leakage current between through-silicon vias (TSVs) and surrounding silicon substrates is a critical electrical reliability problem. Many works have been reported, including factors affecting leakage current, methods to reduce leakage current, leakage current paths and evaluation of TSV yield through leakage current measurement. However, influence of measurement condition or measurement method itself on TSV leakage current was seldom studied in previous works. In this paper, TSV samples with thermal oxidation SiO2 layer and TSV samples with inductively coupled plasma chemical vapor deposition (ICPCVD) deposited SiO2 layers were fabricated and their I-V characteristics of leakage current were measured and compared. Different measurement methods were applied by changing sweeping voltage increments, voltage polarities and single or double sweeping modes. For TSV samples with thermal oxidation SiO2 layers, measured TSV leakage current at 20 V was in the order of 10-12 A and its detailed numerical value increases with sweeping voltage increments. A hysteresis curve was observed as double sweeping mode was applied due to effect of SiO2 layers capacitors charge and discharge processes. TSV samples with ICPCVD deposited SiO2 layers are very leaky and measured leakage current at 20 V was in the order of hundreds of 10-9 A. The influence of sweeping voltage increments and sweeping modes can be neglected for such samples. In conclusion, measurement setup and measurement parameters are important factors to evaluate TSV leakage current. It is important to understand the influence of measurement conditions on the leakage current in TSVs.