* the etch step with fluoroform chemistry is used to remove the residual of the ARC and to etch into the first few nanometer of the silicon nitride layer for an improvement of the adhesion between the metal and the silicon nitride layer.
The etch chemistry based on fluoroform creates an etch rate of [approximately equal to] 60 nm/min for silicon nitride and [approximately equal to] 30 nm/min for the silicon dioxide layer underneath.
According to PBE/6-311++G(d,p) calculations, structural evidence has been adduced to show that the blue-shifting hydrogen bonds and red-shifting hydrogen bonds result from the shortening and lengthening of the C-H of fluoroform
and chloroform, respectively.
The cell morphologies for fluoroform, nitrogen, and carbon dioxide, respectively, are shown in Micrographs 9-11.
Finally, from the foaming agent series, the more polar fluoroform with a higher density and higher dielectric constant than carbon dioxide, solubilizes the reactants at a lower pressure.