Method of fabricating a semiconductor device using two chemical mechanical polishing processes to polish regions having different conductive pattern densities

摘要

A method of manufacturing a semiconductor device is capable of preventing a dishing phenomenon from occurring without using dummy patterns. A plurality of conductive patterns are formed along the entire surface of a semiconductor substrate with an irregular pattern density. The conductive patterns have a first stopper layer at the top thereof. An interlayer insulating layer is formed on the conductive patterns. Next, a second stopper layer is formed on the interlayer insulating layer. An etching mask is formed on the second stopper layer so as to expose a first region having a conductive pattern density that is higher than that of another region(s). By using the etching mask, the second stopper layer and part of the interlayer insulating layer are etched at the first region. The resultant structure is then first polished to expose the first stopper layer at the first region, by using a slurry that provides a polishing rate for the interlayer insulating layer that is higher than that for either the first and second stopper layers. The resultant structure is then polished for a second time to remove the second stopper layer form the region(s) of lower pattern density, by using a slurry that provides a polishing rate that is higher for the second stopper layer than for either the first stopper layer and the interlayer insulating layer.