## 4 Conclusions  
This study investigates the effect of the CDA flow rate, supplied to the purge system and air curtain, on the moisture prevention when the FOUP door was opened in a mini-environment. To reduce any possible vibration, we further developed and tested a prototype for a new panel-purge device in the FOUP during the purging with the door opened and the air curtain in use. During the experiments, the RH evolutions were explored. The following conclusions could be drawn from the present study:  
1. During the pre-purged period with the FOUP door closed, the RHs decreased rapidly and then gradually approached the zero level at the end of the pre-purged process. After the pre-purged process and opening the FOUP door, the RH values increased rapidly and reached the maximum value, which was very close to the RH in the mini-environment. This result indicated that the moisture in the surroundings rapidly entered the FOUP when the door was opened in the mini-environment, without using either the purge system or the air curtain.
2. When the CDA was supplied to both the purge system and the air curtain, the RH values decreased again during the following period. The drop slope of the RH for the diffuser- and panel-purge processes was much larger than that of the conventional-purge process, indicating that the conventional purge inefficiently removed or prevented the moisture from entering the FOUP. In the final stage, the RH gradually approached steady values for the different purge processes. Based on the experimental results, the diffuser purge might be the best approach among three studied cases (i.e., conventional, diffuser, and panel purge approaches).
3. The moisture prevention performance when the developed panel-purge system was used was slightly lower than that when using the diffuser-purge system. However, the use of the panel-purge method could sufficiently suppress the vibration problem. To conclude, the case with CDA flow rates of 150 L/min to the air curtain and 250 L/min to the panel-purge device had the best moisture prevention performance, due to the smallest values for both the mean and maximum RH values in the FOUP.  
The FOUP with the panel-purge device is our proposed concept that can significantly prevent the moisture from entering the pre-purged FOUP, while opening the FOUP door in the mini-environment, based on the results of the present study. At the prototype stage, the cost of the use of the present device is hard to evaluate, but we speculate that the increasing cost compared to the conventional method might be quite small.  
[PERSON] and [PERSON] interpreted the results and prepared the manuscript and revision. [PERSON] conducted experiments. [PERSON] conducted experiments and prepared the revision. This research was supported by the Ministry of Science and Technology, Taiwan (project number: MOST 104-2622-E-027-007-CC2). The authors declare no conflict of interest.  
\begin{table}
\begin{tabular}{c c c c} \hline \hline
**Case Number** & **Mean RH (\%)** & **Maximum RH (\%)** & **Standard Deviation** \\ \hline D-1 & 2.6 & 26.9 & 2.5 \\ D-2 & 3.0 & 30.4 & 2.3 \\ D-3 & 3.0 & 28.5 & 2.3 \\ D-4 & 1.9 & 22.4 & 2.6 \\ D-5 & 1.4 & 14.9 & 2.7 \\ D-6 & 1.3 & 9.5 & 2.2 \\ D-7 & 2.9 & 14.3 & 1.5 \\ D-8 & 6.5 & 17.1 & 0.7 \\ D-9 & 9.8 & 15.5 & 0.4 \\ \hline \hline \end{tabular}
\end{table}
Table 2: Mean and maximum relative humidity (RH) values in FOUP for case D.