As FinFET feature size scaling down, the fins are against more critical challenges by using either self-aligned double patterning (SADP) or self-aligned quadruple patterning (SAQP) method. Wiggling, line width roughness (LWR) and line edge roughness (LER) play more crucial roles at sub-14nm technology and beyond. Traditionally, post plasma treatment methods for photoresist are largely investigated to improve the LWR and LER. For the SADP and SAQP technology, pattern transferring is also another critical feature of dry etch process for pattern line wiggling. In this paper, both plasma photoresist treatment and dry etch process optimization are studied for improving LWR and LER.