CHEMICAL MECHANICAL POLISHING UNSELECTIVE SLURRY, PREPARATION METHOD THEREOF, AND METHOD FOR FORMING PLUG WITHIN THE INSULATING LAYER ON WAFER

摘要

PURPOSE: A chemical mechanical polishing unselective slurry, its preparation method are a method for forming plug within the insulating layer on a wafer are provided, to remove a metal layer, a barrier layer and an insulating layer simultaneously by one polishing, thereby flatting the surface of insulating layer where plug is formed. CONSTITUTION: The unselective slurry comprises the first oxidizing agent for reducing another oxidizing agent; the second oxidizing agent which is reduced by oxidizing a metal layer and whose oxidizing power is restored by the first oxidizing agent; an additive for increasing the polishing velocity of a barrier layer; and an abrasive in aqueous medium. The polishing removing velocities to a metal layer, a barrier layer and an insulating layer are similar each another. Preferably the first oxidizing agent is peroxides and the second oxidizing agent is iron compounds. The unselective slurry is made by preparing strong alkali insulating layer polishing abrasive; adding the first and second oxidizing agents to the abrasive, and adding a pH controlling acid to the mixture to obtain the strong alkali slurry; and adding NH4F to the slurry to control the acidity of the slurry to be weak acidic or weak basic.