Polishing apparatus and method for planarizing on a semiconductor wafer

摘要

An insulating film 246 formed on a semiconductor substrate (201) is polished flat using a carbon film 244 as a stop layer. A polishing slurry containing cerium oxide is used so that the insulating film 246 is not contaminated by alkali metals during the polishing process. The substrate 201 is of silicon and carries layers of silicon dioxide 202 and polysilicon 203. The carbon film 244 is applied by sputtering and forms as an amorphous or finely crystalline layer. In other arrangements the carbon layer extends into recesses in a silicon layer. Polishing apparatus suitable for the method is also disclosed.