화학공학소재연구정보센터
Journal of Vacuum Science & Technology B, Vol.25, No.2, 459-463, 2007
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 X 10(13)-4 X 10(13) at/cm(2) still remain unless the substrate is processed with hydrofluoric acid (HF) wet cleanings where the contamination level is less than 2 X 10(11) at/cm(2). Remote plasma low temperature fluorine post-treatments volatilize dopant residues but are less effective than HF wet cleanings. Dual mode forming gas (4%H-2/96%N-2) plasma post-treatments are ineffective for dopant contamination removal. Low temperature dual mode oxygen plasma treatments followed by high temperature remote oxygen plasma treatments after wet cleaning have lower dopant levels than low temperature dual mode oxygen plasma processing alone. High temperature remote plasma forming gas post-treatments after dual temperature processing volatilize dopant residues. The increased dopant removal effectiveness with dry fluorine remote plasmas, HF wet cleanings, and dual temperature processing is consistent with the surface modification of the underlying silicon into an oxide from ion bombardment, which also drives dopant residues into the underlying oxide.. The surface modification depth from exposure to dual mode. oxygen plasma is about 49-53 angstrom. (c) 2007 American Vacuum Society.