Embodiments of the invention include a method for forming a copper interconnect having a bi-layer copper barrier layer. The method comprising the steps of providing a mixture of reagents based on isocyanate and polyol with the addition of expandable polystyrene-based microspheres, in which method the ratio by weight between the reagents and the expandable microspheres is between, about 7:1 and about 1:2. , in food processing apparatus, includes particular procedures and arrangements for decontaminating the surface of the conveyor.