Ching-Yuan Bai

Effects of Molybdate Concentration on the Characteristics of Ni – Mo – P Diffusion Barriers Grown by Nonisothermal Electroless Deposition

Ternary Ni-based amorphous films can serve as a barrier layer for Cu interconnects in ultralarge-scale integration (ULSI) applications. In this paper, Ni-Mo-P films deposited on silicon wafers without a complicated pretreatment such as Pd activation were prepared using a nonisothermal deposition (NITD) method. The deposition solutions and operating conditions for preparing the Ni-Mo-P alloys are presented, and the effect of the concentration of MoO 2- 4 added in electrolytes on the deposition rate is investigated. The surface morphology, microstructures, compositions, and electrical resistivity of the Ni-Mo-P deposits are also thoroughly examined. Based on the experimental results, the Ni-based ternary alloys produced by the NITD method contain high levels of both Mo and P, and the properties of Ni-Mo-P films are dependent on the concentration of molybdate in electrolytes. It is concluded that the Ni-Mo-P thin films produced by the proposed approach in this study are promising for the 60 nm technologies in ULSI.

The Structure and Properties of Electroless Ni-P and Ni-Mo-P Deposits

The structure and properties of electroless Ni-P and Ni-Mo-P alloys, including the as-plated and annealed deposits, on the aluminum alloy 5052, have been investigated to evaluate the corrosion resistance, thermal stability, electric conductivity, and mechanical characteristics of the coating assemblies. The corrosion behavior of the obtained deposits was examined in a 0.5M H2SO4 environment. The crystal structure of the electroless Ni-based alloys was analyzed by X-ray diffraction (XRD), and the surface morphology and microstructure of Ni-P and Ni-Mo-P alloys were examined by field emission scanning electron microscopy (FE-SEM). The experimental results indicate that the corrosion rate of the Ni-Mo-P coating produced at 70°C and pH 7.0 is almost equals that of the Ni-P film in a 0.5M H2SO4 environment. It is also found that the Ni-Mo-P ternary alloy reveal excellent thermal stability after annealing at 400°C for 1 hr. The electroless Ni-Mo-P deposits have a potential to apply to precision mould and surface metallization of substrates, based on the excellent performance of the ternary alloys.