Characterization of plasma damaged porous ULK SiCOH layers in aspect of changes in the diffusion behavior of solvents and repair-chemicals

The diffusion behavior of different solvents and repair chemicals in a porous SiCOH with pores of ∼ 1,5 nm was studied. It was found for molecule with a size ≤ 1/3 of the pore size the diffusion coefficient (De) depends mainly on the size of the molecule, while a size ≫ 1/3 of the pore size does not show a linear dependency of De on the molecules size. In this regime De is mainly a function of the surface diffusion which depends on the surface energies of the solid and the liquid and adsorption effects. This study show that the porosity and the surface energies influencing the diffusion need to study in order to perform satisfactory cleaning and repair process for ULK dielectric layers.