d) forming {TAIL ~ one or more upper solid insulation layers} over said {HEAD ~ low dielectric constant insulation layer} after said extraction step 
d ) forming { TAIL ~ one or more upper solid insulation layers } over said { HEAD ~ low dielectric constant insulation layer } after said extraction step
OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH