Utility of CHARM®-2 in diagnosing sources of plasma charging damage in high density etchers and in assisting hardware development

In the early years of plasma damage history, much of the focus was on plasma nonuniformity issues. With little understanding of electron shading, many etch related damage issues were diagnosed by placing a CHARM-2 in the etch chamber, running a process and seeing if there was a signal. With high density plasma etchers, typically CHARM-2 would show no signal, though it was suspected that some type of charging damage was taking place. As the understanding of the role of electron shading in plasma charging damage became clear (2), the role of CHARM-2 in detecting plasma damage issues in high density etchers diminished.