Electroless Ni–B plating on SiO2 with 3-aminopropyl-triethoxysilane as a barrier layer against Cu diffusion for through-Si via interconnections in a 3-dimensional multi-chip package

Electroless Ni–B was plated on SiO2 as a barrier layer against Cu diffusion for through-Si via (TSV) interconnections in a 3-dimensional multi-chip package. The electroless Ni–B was deposited on the entire area of the SiO2 side wall of a deep via with vapor phase pre-deposition of 3-aminopropyl-triethoxysilane on the SiO2. The carrier lifetimes in the Si substrates plated with Ni–B/Cu did not decrease with an increase in annealing temperature up to 400 °C. The absence of degradation of carrier lifetimes indicates that Cu atoms did not diffuse into the Si through the Ni–B. The advantages of electroless Ni–B (good conformal deposition and forming an effective diffusion barrier against Cu) make it useful as a barrier layer for TSV interconnections in a 3-dimensional multi-chip package.