Development of nanoprobe TOF-RBS system for semiconductor process

Medium energy (80-400 keV) Be and Si ion beams have been used to enhance scattering cross section in Rutherford backscattering spectroscopy. A multiscaling time-of-flight (TOF) detecting system with a large area micro-channel plate detector was installed to obtain high counting rate and enhanced mass resolution. A pulse width of less than 1 ns for beam chopping of TOF and chopping plates installed in the middle of an ExB mass filter resulted in the improvement of the time resolution. Obtained time resolutions of 2.14 and 3.56 ns for 100 keV Be+ and Si+, respectively, provided adequate mass resolutions to identify almost all contaminated heavy metals on Si