The characteristics of FA/O chelating agent with extremely strong chelating ability were used for the chemical-mechanical planarization of copper interconnection on the conditions of abrasive-free slurry and low down pressure to obtain a high polishing rate and a fine within-wafer non-uniformity (WIWNU). The planarization principle of the abrasive-free alkaline slurry technology of the copper surface at low down pressure was put forward. Based on the analyzing of the planarization principle and the chemical reaction mechanism in abrasive-free alkaline slurry at low down pressure the main ingredient and prescription of slurry(containing FA/O chelating agent and oxidizer ) and polishing technological parameter (pressure and speed) were investigated. The results indicate that the polishing rate can reach 1825 nm/min and WIWNU is 0.25 when the down pressure is 6.3 kPa, the polishing machine speed 60 r/min, the slurry contains 5vol% chelating agent and 1 vol% oxidizer.