Analysis of Acoustic Emission Signal Sensitivity to Variations in Thin-film Material Properties During CMP Process

CMP 공정중 박막 종류에 따른 AE 신호 분석

  • Received : 2014.04.16
  • Accepted : 2014.05.14
  • Published : 2014.08.01


In this study, an acoustic emission (AE) sensor was used for measuring the abrasive and molecular-scale phenomena in chemical mechanical polishing (CMP). An AE sensor is a transducer that converts a mechanical wave into an electrical signal, and is capable of acquiring high-level frequencies from materials. Therefore, an AE sensor was installed in the CMP equipment and the signals were measured simultaneously during the polishing process. In this study, an AE monitoring system was developed for investigating the sensitivity of the AE signal to (a) the variations in the material properties of the pad, slurry, and wafer and (b) the change in conditions during the CMP process. This system was adapted to Oxide and Cu CMP processes. AE signal parameters including AE raw frequency, FFT, and amplitude were analyzed for understanding the abrasive and molecular-level phenomena in the CMP process. Finally, we verified that AE sensors with different bandwidths could function in complementary ways during CMP process monitoring.


CMP;Acoustic Emission Sensor;Monitoring System;Oxide Wafer;Cu Wafer


  1. Wang, L., Gao and Rovert, X., 2006, "Condition Monitoring and Control for Intelligent Manufacturing," Springer, pp. 126-129.
  2. Karpuschewski, B., Wehmeier, M. and Inasaki, I., 2000, "Grinding Monitoring System Based on Power and Acoustic Emission Sensor," CIRP Annals-Manufacturing Technology, Vol 49, Issue 1, pp. 235-240.
  3. Lturrospe, A., Dornfeld, D. A., Atxa, V. and Abete, J. A., 2005,"Biceptrum Based Blind Idendification of the Acoustic Emission(AE) Signal in Precision Turning," Mechanical Systems and Signal Processing, Vol 19, Issue 3, pp. 447-466.
  4. Choi, J. H. and Lee, D. E., 2005, "In-Situ Acoustic Emission Monitoring of Surface Chemical Reactions for Copper CMP," CMP-MIC, pp. 415-422.
  5. Jeong, H. D., Kim, H. J., Lee, S. H. and Dornfeld, D. A., 2006, "Multi-Sensor Monitoring System in Chemical Mechanical Planarization(CMP) for Correlations with Process Issues," CIRP Annals-Manufacturing Technology, Vol 55, Issue 1, pp. 325-328.
  6. Lee, H. S., Park, B. Y., Kim, G. Y., Kim, H. J., Seo, H. D. and Jeong, H. D., 2004, "Effects of Friction Energy on Polishing Results in CMP Process," Trans. Korean Soc. Mech. Eng. A, Vol. 28, No. 11, pp. 1807-1812.
  7. Lee, H. S., Park, B. Y., Seo, H. D., Jang, W. M. and Jeong, H. D., 2005, "A Study on the CMP of Lithium Tantalate Wafer," Trans. Korean Soc. Mech. Eng. A, Vol. 29, No. 9, pp. 1276-1281.
  8. Berman, M., Bibby, T. and Smith, A., 1998, "Review of In Situ & In-line Detection for CMP Applications," Semiconductor Fabtech, 8th edition , pp. 267-274.
  9. Lee, Y., Chang, A. K. and Dornfeld, D. A., 2002, "Acoustic Emision Monitoring for the Diamond Machinging of Oxygen-free High-conductivity Copper," Journal of Materials Processing Technology, Vol 127, No.2, pp. 199-205.