Characterization of CF/sub 4/ plasma induced damage during dry ashing and residue removal process

As devices get into deep sub-micron generations, more than 25 photoresist steps are basic process requirements. More complex S/D engineering implants must be optimized for both core device and I/O device performances. In addition, for photoresist stripping, ashing technology has become a critical issue for high dose implant layers to completely remove carbonized PR residue. Adding fluorine-based gases like CF/sub 4/ during the ashing process (high dose implant layer) can effectively improve photoresist stripping capability but will lose some device performance. In this work, we discuss the CF/sub 4/ impact on the dielectric integrity of the gate oxide and increased nonsilicide poly resistance.