Corrosion-related defect control

A general criterion for optimizing the metal CMP process is the controlled regulation of material removal, while simultaneously securing the processed surface from various CMP-related defects like scratches, dishing, delamination, erosion, contamination, line deformation, and galvanic corrosion (Baneijee and Rhoades, 2008 Choi and Korach, 2009). The considerations for improving material removal rates (MRRs) are mostiy relevant in the context of bulk Cu CMP, but are relatively less critical for the thin (<5 nm) diffusion barrier metal films. However, the requirement for defect control continues to remain a major issue in essentially all cases of metal CMP (Chandrasekaran et al., 2004). 

Risk evaluation programmes exist, for pressure vessels, which take into account European Directives [12] the risk factor - related to material brittleness and embrittlement, corrosion effects and localised stresses - is elevated and requires the adoption of rigorous safety measures. The manufacture and control procedures - including welding parameters and structural solutions - should be, in this case, more accurate and devoted to avoid the described defects. 

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