Dishing and erosion in STI CMP

Abstract

The effect of pattern density, trench width and selectivity of slurry on dishing and erosion in STI CMP process was investigated by using specially designed isolation pattern. As trench width gets wider and active pattern density gets higher, dishing becomes more severe. Low selectivity slurry shows less dishing at over 20 /spl mu/m trench width, whereas high selectivity slurry shows less dishing at below 20 /spl mu/m trench. Erosion of low active pattern density area is more severe and it is not affected by trench width. Generally, high selectivity slurry induces less erosion.