CxFy, O2, and Ar are three gases that typically are used for the BARC opening process. O2 is used for combusting carbon, CxFy is used for increasing selectivity of BARC to resist, and Ar is used for promoting the sputtering component.In this study, we chose CF4, O2, and Ar as etch gases. A series of experiments were designed in mixture model with a constant total gas flow rate and variable gas ratios. The result was analyzed in Design Expert 7 software to find the behavior of different polymers in plasma etching