ABSTRACT
Shallow trench isolation (STI) Chemical-mechanical planarization (CMP) processes with conventional oxide polishing slurries require either a reactive ion etching; etch back preplanarization step, or very tight control of the CMP process. CMP was performed with the ceria slurry, which was prepared by adding an adequate amount of commercially available anionic acrylic polymers. During the CMP, the agglomerated particles were easily stuck to the wafer surface by the small interactive force between the abrasive and oxide film. The removal rate of the STI CMP process depends not only on the electrokinetic behaviors of abrasive ceria particles and the deposited films, but also on the conformation of the adsorbed polymer. The oxide-to-nitride selectivity is a very important factor in the STI CMP process. It can significantly affect the CMP induced defects, such as erosion or dishing, and also be important for endpoint detection.
