## 5 Conclusions  
This study has developed and completed a dynamic pad measurement system (DPMS) of surface topography for chemical mechanical polishing/planarization (CMP) process of IC fabrication. The integration of a chromatic confocal measurement probe into a dressing arm in CMP tool can be used for in-process acquiring pad topography for accessing the pad performance index. The measuring time can be minimized with the motion of the pad conditioning arm and not affecting the CMP throughput. Two major indexes of PU and PELI are presented to identify the status and performance level of the pad during the CMP process. Relationship of wafer quality and pad performance index are discussed by 50 rounds of CMP experiments. The change of PELI and PU are obvious, the wear of pad can be observed by the SEM cross-section photos. The PELI starts from 99.2% and ends with 34.61%, in which the groove is almost gone in the inner part of pad. The PU is 1.9% to 58.7% from start to end. The PU and PELI have high correlations, \(-\)0.94 and 0.94, with wafer MRR. Considering wafer Sa remains in the early stage of the experiments, the PU and PELI also highly correlated with wafer Sa for calculating the late stage of the experiments of 0.93 and \(-\)0.91. The MRR is changing with the wear of pad during CMP experiments, and the wafer Sa is affected by pad profile when the pad cutting rate (PCR) increases to a certain level. In this study, the Sa value will be highly correlated when PELI is below 66.8%. The MRR drops by 64% and wafer Sa raises 35% with the PELI decreasing by 64.6% and PU increasing by 56.8%.  
Results of the study show that the developed DPMS can monitor the change of pad surface profile, which are significantly correlated with wafer quality by CMP. Experimental results can be used positively to predict pad life time for in-process process control of the CMP process.  
\begin{table}
\begin{tabular}{c c c c} \hline \hline
**Wafer/Pad Index** & **MRR(nm/min)** & **Sa(\(\mu\)m)** & **Sa(\(\mu\)m)** \\  & & & **Last 25 rounds** \\ \hline PU(\%) & \(-\)0.94 & 0.76 & 0.93 \\ PELI(\%) & 0.94 & \(-\)0.76 & \(-\)0.91 \\ \hline \hline \end{tabular}
\end{table}
Table 6: Correlations of Wafer and pad index.  
Figure 17: The correlations between wafer Sa and PELI.  
**Author Contributions:** Conceptualization, C.-C.A.C. and J.-C.L.; Methodology, J.-C.L.; Software, J.-C.L., W.-C.L., Y.-J.C. and C.-C.C.; Validation, J.-C.L., W.-C.L. and Y.-J.C.; Formal Analysis, C.-C.C.; Investigation, J.-C.L. and C.C; Data Curation, J.-C.L.; Writing--Original Draft Preparation, J.-C.L.; Writing--Review & Editing, J.-C.L.; Project Administration, C.-C.A.C.; Funding Acquisition, C.-C.A.C. All authors have read and agreed to the published version of the manuscript.  
**Funding:** Authors appreciate for the financial funding of the research project collaborated with Ta Liang Technology Co., Ltd. supported by the Industrial Value Creation Program (grant number: 108-EC-17-A-05-S3-054) from the Academia by the Ministry of Economic Affairs (MEA), Taiwan.  
**Institutional Review Board Statement:** Not applicable.  
**Informed Consent Statement:** Not applicable.  
**Data Availability Statement:** Data sharing not applicable.  
**Conflicts of Interest:** The authors declare no conflict of interest.