IN-SITU ELECTROCHEMICAL AND MECHANICAL MEASUREMENTS TO UNDERSTAND THE CMP POLISHING PHENOMENA

摘要

The planarity, defectivity and the polish rate in a CMP process are dependent on the chemical and mechanical interactions involving the formation and the removal of a chemically modified surface layer. The objective of this research is to investigate the dynamics of the chemically modified surface layer formation during copper CMP and contact variables such as the fractional surface coverage of the particles on CMP. We have investigated two in-situ measurements: (ⅰ) in-situ electrochemical measurements, which provide information on the chemical changes on the surface due to additives in the slurry and (ⅱ) in-situ friction force measurements, which were expected to provide fractional surface coverage of particle during CMP. The results show that hydrogen peroxide led to the formation of a surface layer at a constant rate, whereas the addition of BTA led to passivation of the surface. In-situ friction force measurements showed that the fractional surface coverage of particles on the wafer is dependent on the particle size and concentration and is independent of down force.