Contamination inspection on wafer with oxide or nitride film by using a vibrating contact potential difference probe

Contamination inspection on the oxide and nitride films deposited on silicon wafer surface by using vibrating contact potential difference (CPD) probe is presented in this paper. Contaminants induce the variation of the CPD between a dielectric layer and the probe material. However, the screening effect of the charges on the surface, interface and in the dielectric layer overwhelms the contamination signals when using the vibrating CPD monitor. This obstacle can be overcome using the signal characteristic diagnosis by which most of the charge signals can be filtered out. The validity of this approach was verified by means of the vapor phase decomposition coupling with inductively coupled plasma mass spectrometry (VPD‐ICP‐MS), and we found that the filtrated contamination signals were correlated closely with the metallic concentration. Moreover, the proper annealing process could enhance the response signals of contaminants, especially for Ni and Cu, in the nitride film monitoring. This inspection method was effectively applied in the trace metallic contamination routine monitor and the contamination source tracing of the furnace tools. Copyright © 2010 John Wiley & Sons, Ltd.