A novel method to characterize the effect from the diffusion of Cu in through silicon via (TSV)

To characterize electrically the effect of the Cu diffusion in TSVs, a new test pattern is proposed and its effectiveness is verified experimentally. The test pattern has a shallow n+ region formed in an n-well region butted to the TSV dielectric surrounding the TSV. Through the n+/n well region, we can measure the diode and gated diode currents, the charge pumping current, and C-V to accurately analyze the effect. Our approach is demonstrated to be very useful by investigating the Cu diffusion effect in samples with two different barrier metal thicknesses.