Selective electroless nickel plating on oxygen-plasma-activated gold seed-layers for the fabrication of low contact resistance vias and microstructures

This paper presents a novel technique to selectively deposit nickel by electroless plating on gold seed layers using an oxygen-plasma-activation step. No prior wet surface pre-treatments or metal oxide etches are required. This enables the manufacturing of low-resistance vias for heterogeneous three-dimensional (3D) integration of MEMS but it is also a suitable technique for the fabrication of arbitrary shaped nickel-microstructures using chemically stable and cost-effective electroless nickel plating baths.