Influence of CMP process on defects in SiOC films and TDDB reliability

The relationship between the TDDB (time-dependent dielectric breakdown) reliability and defects in the Cu CMP (chemical-mechanical polishing) process, such as corrosions, scratches and pittings, was investigated using Cu/SiOC interconnects. Cu corrosions generate at edges of wires and this results in the TDDB degradation. Scratches on the SiOC surface also degrade the TDDB lifetime even if other defects are removed. The slurry without the BTA solutions causes not only pittings, but also Cu dissolution. In this condition, some dissolved Cu atoms remain on the SiOC surface between adjacent Cu wires. This also leads to the TDDB degradation. It is essential to prevent corrosions, scratches and pittings to improve the TDDB reliability.