Patent ID: 7696095

Claim:
A method for polishing a topographic layer consisting only of dielectric silicon dioxide having areas of up oxide and areas of down oxide, the method comprising: providing, on both the areas of up oxide and the areas of down oxide, an aqueous slurry composition comprising from about 0.5% to about 10.0% by weight of ceria abrasive particles, and from about 0.006% to about 0.04% by weight of polyethyleneimine; and polishing the topographic dielectric silicon dioxide layer using a polishing pad with the aqueous slurry composition disposed therebetween to remove the areas of up oxide and thereby achieve a polished surface consisting only of dielectric silicon dioxide having a predetermined minimum step height of less than about 500 Å; wherein: (i) the aqueous slurry composition exhibits auto-stopping behavior once the predetermined minimum step height is achieved; (ii) the aqueous slurry composition maintains a topography selectivity of at least about 5 or higher for a polishing period that includes over-polishing for twenty-five seconds after the predetermined minimum step height is achieved, where the topography selectivity is expressed as the ratio of the rate at which the areas of up oxide are removed to the rate at which the areas of down oxide are removed during polishing; and (iii) the aqueous slurry composition maintains an overall polishing efficiency percentage of greater than 90% for the polishing period that includes over-polishing for twenty-five seconds after the predetermined minimum step height is achieved, where the overall polishing efficiency percentage is expressed according to the equation: ((amount of up oxide removed−amount of down oxide removed)/amount of up oxide removed)×100.