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