A fundamental study was undertaken to evaluate the usefulness of a sulfonic acid-based chemical system for the removal of tantalum under electrochemical mechanical planarization conditions. Tantalum as well as copper samples were polished at low pressures (∼0.5 psi) under galvanostatic conditions in dihydroxy benzene sulfonic acid (DBSA) solutions maintained at different pH values. At a current density of 0.5 mA cm2 and pH 10, tantalum removal rate of ∼200 Åmin with a 1:1 selectivity to copper has been obtained in 0.3 M DBSA solutions containing 1.2 M H2 O2. The presence of a small amount (∼0.1%) of colloidal silica particles is required to obtain good removal rates.
ASJC Scopus subject areas
- Electronic, Optical and Magnetic Materials
- Renewable Energy, Sustainability and the Environment
- Surfaces, Coatings and Films
- Materials Chemistry