Driven by “Moore’s Law”, the semiconductor industry pushes to achieve aggressive node scaling. Self-aligned Quadruple Patterning (SaQP) scheme is widely deployed for Fin formation in the Front-End-of-Line FinFET production, where two polycrystalline Silicon mandrels (MD1 and MD2) and corresponding Silicon Oxide or Nitride mandrel spacers (MD1SP and MD2SP) are patterned for accurate CD transferring for the final Fin pattern of interest. However, dummy Fin cutting (MD2SP Cut) is the major challenge. The MD2SP Cut etching processes in patterning of multiple areas require progressively smaller etch bias loading between isolated and dense (Iso-Dense) patterns as the target features scale. The influence of etch bias on mask patterning is shown in Figure 1. The large etch bias loading differences between Iso-Dense patterns will produce the corner rounding effect at the junction, which will lead to the damage of the designated activate area (AA) in the SaQP process. Therefore, it is particularly important to improve the etch bias loading between Iso-Dense patterns. This work improved the loading effect by delicately adjusting HBr curing and polymer depositing processes during MD2SP Cut etching. The Iso-Dense etch bias loading improved by 71% as a result, which can contribute to a more precise CD control in multiple patterning.