Surface modification and contamination characterization of ion-enhanced, implanted photoresist removal

The authors study the dopant contamination removal effectiveness of blanket high-dose implanted photoresist wafers exposed to dual mode oxygen plasma, where a remote rf-plasma source is operated simultaneously with rf bias at low temperature. Based on total x-ray reflectance x-ray fluorescence spectrometry and secondary ion mass spectrometry analyses, sputtering effects are minimal during typical process times with most of the dopant remaining on the substrate after dual mode oxygen plasma processing. SC1-based (NH4OH:H2O2:H2O Standard Clean 1) wet clean treatments reduce dopant levels but 2×1013–4×1013at∕cm2 still remain unless the substrate is processed with hydrofluoric acid (HF) wet cleanings where the contamination level is less than 2×1011at∕cm2. Remote plasma low temperature fluorine post-treatments volatilize dopant residues but are less effective than HF wet cleanings. Dual mode forming gas (4%H2∕96%N2) plasma post-treatments are ineffective for dopant contamination removal. Low temperature dual ...