Fluorocarbon polymer deposited by inductively coupled plasma oxide etching

Polymer layers deposited by inductively couple plasma (ICP) oxide etching have been studied. A 180 nm thick polymer layer was deposited at the bottom of 0.4 mu m contact holes during ICP etching with C3F8/Ar. The deposited layer was a carbon-rich fluorocarbon polymer as indicated by electron spectroscopy for chemical analyses. The etching rate of this layer in an ICP oxygen ashing process was very low, showing its stability. When the carbon-rich polymer was formed at the Ti/Si interface, the silicidation reaction did not occur uniformly at high temperatures. Since effective contact area became very narrow in this titanium silicide ohmic contact, high contact resistance was obtained.