Plasma damage evaluation of an integrated in-situ directional resist stripping process in magnetically enhanced RIE etcher for dual damascene application

This paper demonstrates the plasma induced device damage performance of a directional resist removal process for Cu/low-k dielectric dual damascene interconnect integration application. A Magnetically Enhanced Reactive Ion Etching (MERIE) chamber running oxygen based plasma is used for this study with a clean chamber mode. Parameters including power, pressure, overetch and gas species are investigated on the plasma induced charging damage of 0.25 μm technology devices. It is found that power is the most sensitive parameter than B-field, pressure, overetch and gas species to control damage. A contact bottom polymer/etch stop nitride shielding mechanism is proposed to explain the plasma damage sensitivity in oxygen plasma environment