## 7 Analysis of Group 3 Performance  
### Data Overview: Group 3  
The experimental data used in this group consists of measurements of the process unused ratio (1-Ui) across plasma intensity levels over 1000 for three gases: C4F6, C4F8, and CF4. For each gas, 1-Ui values were recorded at plasma levels of 1000, 2000, and 3000 with a 300 mm wafer, allowing for statistical analysis of the relationship between plasma intensity and 1-Ui unused gas ratio. Summary statistics of 1-Ui by gas and plasma are shown in Table 12.  
To assess the effect of plasma intensity on 1-Ui, box plots of 1-Ui were constructed for each gas at varying plasma levels. This visualization provides insight into the influence of plasma intensity, allowing for comparative analysis across gases and plasma levels.  
As shown in the box plot of the C4F8 in Figure 9, at a plasma intensity level of 1000, the distribution of 1-Ui values is centered around 0.5, with some instances as low  
\begin{table}
\begin{tabular}{c c c c c c c c c c} \hline
**Gas** & **Plasma** & **Count** & **Mean** & **Std** & **Min** & **25\%** & **50\%** & **75\%** & **Max** \\ \hline C4F6 & 1000 & 302 & 0.11 & 0.03 & 0.06 & 0.11 & 0.11 & 0.29 \\ C4F6 & 2000 & 302 & 0.12 & 0.03 & 0.06 & 0.11 & 0.12 & 0.12 & 0.30 \\ C4F6 & 3000 & 302 & 0.05 & 0.03 & 0.00 & 0.03 & 0.04 & 0.05 & 0.21 \\ C4F8 & 1000 & 1033 & 0.48 & 0.14 & 0.01 & 0.50 & 0.51 & 0.52 & 0.90 \\ C4F8 & 2000 & 855 & 0.35 & 0.10 & 0.01 & 0.36 & 0.37 & 0.37 & 0.69 \\ C4F8 & 3000 & 689 & 0.34 & 0.10 & 0.02 & 0.35 & 0.36 & 0.36 & 0.70 \\ CF4 & 1000 & 305 & 0.37 & 0.04 & 0.25 & 0.35 & 0.36 & 0.36 & 0.55 \\ CF4 & 2000 & 304 & 0.33 & 0.04 & 0.20 & 0.31 & 0.32 & 0.32 & 0.56 \\ CF4 & 3000 & 305 & 0.26 & 0.04 & 0.19 & 0.24 & 0.25 & 0.25 & 0.50 \\ \hline \end{tabular}
\end{table}
Table 12: Summary statistics of 1-Ui by gas and plasma.  
Figure 8: Distribution of 1-Ui by plasma for CH2F2 and CHF3.  
as 0.2, indicating a relatively high unused gas ratio. At a plasma intensity level of 2000, the distribution narrows significantly, centering more precisely around 0.37, suggesting increased consistency and a modest reduction in the unused gas ratio compared to 1000. At a plasma intensity of 3000, the distribution remains similar to that observed at 2000, with an even greater concentration of 0.3 to 0.4, further demonstrating performance stability at higher plasma intensities. These findings indicate that as plasma intensity increases, the distribution of 1-Ui for C4F8 becomes more stable and predictable, with a moderate reduction in the unused gas ratio.  
As presented in Figure 10, 1-Ui values for CF4 are primarily concentrated around 0.35 at a plasma level of 1000, indicating stable performance at this intensity. At a plasma level of 2000, the distribution shifts slightly, centering between 0.30 and 0.35, demonstrating sustained stability but with a marginally lower unused rate than at level 1000. By plasma level 3000, the distribution narrows around 0.25, signifying a continued reduction in unused rates as plasma intensity increases. These findings suggest that CF4 exhibits consistent unused gas rates across plasma levels, gradually decreasing 1-Ui as plasma intensity rises. Thus, plasma intensity is crucial in reducing the unused rate for CF4.  
Figure 10: Boxplot of 1-Ui by plasma levels for CF4.  
Figure 9: Boxplot of 1-Ui by plasma levels for C4F8.