In-situ Cleaning of Post-etch Byproducts by Manipulating Dechucking Environment Gas in Silicon Etch Process

In this work, the ability to remove post-etch residues by simply changing dechucking environment gas from Ar to O
2
is presented. The O
2
dechucking process was observed to enhance in-situ cleaning effect, reducing Cl and Br anion by 93% and 50%, respectively, on the wafer surface (HPIC) and 10
¹
~ 10
²
times within the Si substrate (tof-SIMS). FOUP ion analysis and optical emission spectroscopy results also revealed that the amount of process outgas can be significantly reduced. As the halogen atoms that are originally remaining inside the Si substrate was removed, the damaged Si layer was also reduced by O
2
curing. By this simple method, within the etch process, the wafer can be patterned and additionally, in-situ cleaned. Furthermore, based on DFT calculation, we clarified that O radicals can remove polymeric residues like SiO
x
Cl
y
and SiO
x
Br
y
by replacing halogen atoms on energy perspective. The O
2
treated oxide has less number of interface trap (Nit), proving device performance also can be enhanced.