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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

Abstract

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.

Keywords

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

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