Effect and mechanism analysis of sarcosine on the chemical mechanical polishing performance of copper film for GLSI

With the decrease of integrated circuits feature size, chemical mechanical polishing (CMP) of copper (Cu) film for multilayer wiring is faced with new challenges. In order to reduce the step height of Cu film for cobalt-based Cu interconnect during CMP process, the selection of additives in the slurry is crucial. In this paper, sarcosine was used as an important additive in Cu slurry to improve the planarization properties. Through the polarization curves, dynamic polishing, static etching experiments and scanning electron microscopy (SEM) measurement, it was identified sarcosine as a complexing agent and trace functional reagent could improve the Cu planarization properties. Meanwhile, the adsorption and complexation mechanisms of sarcosine on Cu film surface were analyzed by electrochemical tests and X-ray photoelectron spectroscopy (XPS). The improvement of static etching and surface quality of Cu patterned wafers by sarcosine was verified by laser scanning confocal mi-croscopy (LSCM). Low static etch rate (SER) (1658 angstrom/min), high removal rate (RR) (5091 angstrom/min), RR/SER of 3.07 and effective correction of the step height on Cu patterned wafers were achieved by the synergistic effect of sarcosine and benzotriazole (BTA). In this study, a green functional reagent for Cu film CMP in low-tech node multilayer wiring was provided, which is good practical application prospects.

Automated summary

This paper investigates the influence of the additive sarcosine on the chemical mechanical polishing (CMP) process of Cu film. Results show that sarcosine, as a complexing agent and functional reagent, can improve the planarization properties of Cu film. The adsorption and complexation mechanisms of sarcosine on the Cu film surface are analyzed through various experiments and tests. The synergistic effect of sarcosine and benzotriazole is also confirmed to effectively correct the step height and improve the surface quality of Cu patterned wafers.