Developments for Physical Cleaning Sample with High Adhesion Force Particles and Direct Measurement of its Removal Force

We quantitatively evaluate the wet cleaning performance of particle cotamination. We made particle sample which endure the wet cleaning and measured particle adhesion force by self-sensitive cantilever. The advantage of this method is that performed in both air and water. As a result, there were no significant differences between the air and water condition and the influence of particle size were dominant. Using this sample, we demonstrated particle removal rate of droplets impacts and PVA brush.

Frictional behavior and particle adhesion of abrasive particles during Cu CMP

The friction behavior and adhesion of abrasive particles were experimentally investigated during Cu CMP process. The highest particle adhesion force was measured in alumina slurry without citric acid. However, the alumina slurry with addition of citric acid had the lowest particle adhesion due to the adsorption of citrate ions on the alumina surfaces. While citrate ions could be easily adsorbed on alumina particles, silica particle showed the least effect on adsorption in citric acid solutions. The magnitude of adsorptions of citrate ions on the particle surfaces had significant effect on frictional behavior as well as adhesion force. Higher particle adhesion force resulted in higher friction, particle contamination and scratches in CMP process. It indicates that the magnitudes of particle adhesions on wafer surfaces in slurries can be directly related to the frictional behavior during CMP process.