# An Efficient Analytical Approach to Visualize Text-Based Event Logs for Semiconductor Equipment
## 4 Experiment and Results
### EventLog Visualization Results  
After configuring the system and storing the EventLogs in the DB, the result of the analysis was as follows. Existing text-based EventLogs are not intuitive, and it often takes a long time to find the exact location. By expressing the EventLogs in various forms, we can more easily find the cause of the problem and understand the overall contents.  
* Expressing the Frequency of Event Occurrence by Module: As shown in Figure 8, The subject generating the event is recorded in the EventLog, and it was designated as an issuer. If it draws the cumulative chart for each event issuer, it can yield the following screen. This type can be used in various ways. For example, you can view alarms by type in the Alarm Log, and you can also check the total number of alarms.
* Expressing the Amount of Change Over Time: There are cases where one needs to monitor how parameters change over time as shown in Figure 9. For example, it is crucial to managing the accumulated Radio Frequency (RF) On-time in the process chamber in Etch equipment. In this case, it is possible to draw a trend chart as follows by overlapping several EventLogs and displaying several parameters together.
* Monitoring Success and Failure by Period: A macro is a kind of script that automatically checks things that have been manually checked by the operator in the equipment. Some of these macros are executed daily, and there are cases where macros are executed under certain conditions. We can check whether the executed macro was executed typically or was abnormally terminated. Pass or Fail information may be utilized as a future monitoring feature as in Figure 10. It can be used to monitor the entire equipment and to monitor the equipment that frequently fails.
* WaferMap; Map information about wafers is stored in the EventLog, and a WaferMap can also be drawn using this information. WaferMap information is vital information.  
\begin{table}
\begin{tabular}{c c c c} \hline
**1582 Channels (22.5 Min), 10 Hz** & **Unzipped [MB]** & **Zipped [MB]** & **Compression Rate** \\ \hline ASCII & 201.8 & 10.0 & 95\% \\ TDMS & 99.9 & 3.5 & 96\% \\ Size Reduction & 51\% & 64\% & \\ \hline \end{tabular}
\end{table}
Table 1: ASCII vs. TDMS Compression Ratio Comparison.  
Figure 7: ASCII vs. TDMS Memory Usage Comparison.  
With this information, if it can draw a map before and after the process proceeds, it can judge the process result through the wafer map as in Figure 11. These Map data can also be used to compare before and after Etch.
* Check the Idle Section: In semiconductor equipment, the event when the recipe starts and ends is recorded. If we express this below, we can check where the chamber is idle. If we mark the start and end parts at the beginning and end of the recipe and expand to information of recipe parameters for each step, we can analyze how the equipment operated at that time. In addition, it is possible to compare why the delay between two or more pieces of equipment occurs by using this information. The equipment performance degradation can be analyzed by checking and analyzing the delayed section until the recipe starts and ends. It can also compare the data between two equipment with differences in throughput to see the delay interval. Through visualization, it can easily find the section where Idle occurs as in Figure 12.  
Figure 8: Event Occurrence Frequency by Module.  
Figure 10: Success and Failure Monitoring.  
Figure 9: Trend Chart of Multiple Parameters for The Amount of Time Change.