Optimization of shallow trench isolation formed with a resist etch-back (REB)/chemical mechanical polish (CMP) process is described. For an REB/CMP process, planarity is determined by the within-die nitride thickness range between features of varying size and pattern density. The nitride thickness range within die is reduced significantly by optimizing the tetraethylorthosilicate (TEOS) thickness and the amount of nitride polish. A thicker TEOS/reduced polish process results in excellent planarity across all features with a total active area to field oxide step height range of less than 300 Angstrom.