Control of thickness of interconnect line during chemical mechanical polishing of barrier layer on copper interconnect.

The thickness of interconnect line (THK) in copper interconnect trench plays a crucial role in the performance of integrated circuit, making it an important evaluation parameter in IC manufacturing process. FA/O II as copper chelating agent, potassium citrate (CAK) as accelerator, and 1,2-benzisothiazolin-3-one (BIT) as bacteriostatic agent were added to an oxidant- and corrosion inhibitor-free alkaline slurry for chemical mechanical polishing (CMP) of the barrier layer of copper interconnect, and the effects of their mass fractions in the slurry on the removal rates of Cu and TEOS (tetraethyl orthosilicate) and THK were studied. The results showed that the removal rate ratio of TEOS to Cu influences the THK, and the THK is negatively correlated with the resistance of barrier layer. The removal rate ratio of TEOS to Cu was about 1.7 when the mass fractions of FA/O II, CAK, and BIT in the slurry were 0.8%, 1%, and 0.04%, respectively, the THK was 225 nm, and the resistance of barrier layer was 0.18 Ω, meeting the requirements of industrial production. [ABSTRACT FROM AUTHOR]