Douglas Holmes

Molecular design for inhibition of titanium corrosion in resist cleaner systems

Abstract A range of substituted catechols and pyrogallols are examined as corrosion inhibitors for titanium during processing with resist cleaners in the microelectronic industry. The corrosion inhibition is consistent with an adsorption mechanism and the best predictor for inhibition performance is found to be the hydrophobicity of the molecule. The trihydroxybenzenes adsorb more strongly on the titanium surface than the corresponding dihydroxybenzene compounds. It is also shown that trace quantities of calcium act as an extremely effective inhibitor. Consequently, calcium levels in the organic material must be reduced to less than ≈2 ppm before measurement of the inhibition efficiency.

Advanced Aqueous Cleaner II: PER Removal from Sensitive Cu/Low-k Devices

This paper described the development of two types of Advanced Aqueous Cleaners (AAC™) for Aluminium (Al) Post Etch Residue (PER) removal. The first approach was developed to address a need for cleaning chemistries with a smaller environmental footprint that were also able to clean at significantly lower process times and temperatures than conventional wet chemical cleans. A broad screening experiment was undertaken during which it was highlighted it was possible to clean Al lines in an acidic region though this technology was not extendable to cleaning via features. However, the study emphasised the need to use a selective alkaline reducing formulation to maintain a high cleaning efficiency for the more complex residues formed during via etch. The novel Back End Of Line (BEOL) PER cleaners presented in this paper were optimised using a statistical Design Of Experiment (DOE) to perform at lower temperatures and shorter process times and were Fluoride and organic solvent free while containing a minimum of 80%wt water.

Advanced Aqueous Cleaner I, Dilute Solutions for the Selective Removal of Post Etch Residues in the Presence of Aluminium

This paper described the development of two types of Advanced Aqueous Cleaners (AAC) for Aluminium (Al) Post Etch Residue (PER) removal. The first approach was developed to address a need for cleaning chemistries with a smaller environmental footprint that were also able to clean at significantly lower process times and temperatures than conventional wet chemical cleans. A broad screening experiment was undertaken during which it was highlighted it was possible to clean Al lines in an acidic region though this technology was not extendable to cleaning via features. However, the study emphasised the need to use a selective alkaline reducing formulation to maintain a high cleaning efficiency for the more complex residues formed during via etch. The novel Back End Of Line (BEOL) PER cleaners presented in this paper were optimised using a statistical Design Of Experiment (DOE) to perform at lower temperatures and shorter process times and were Fluoride and organic solvent free while containing a minimum of 80%wt water.