The porous insulation layer is formed by a chemical vapor deposition of {TAIL ~ a mixture} of the insulation material and a second extractable material; and then subsequently selectively removing the second extractable material, thereby leaving behind a porous matrix of the insulation material, comprising {HEAD ~ the low dielectric constant insulation layer} 
The porous insulation layer is formed by a chemical vapor deposition of { TAIL ~ a mixture } of the insulation material and a second extractable material ; and then subsequently selectively removing the second extractable material , thereby leaving behind a porous matrix of the insulation material , comprising { HEAD ~ the low dielectric constant insulation layer }
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD