The method 1, wherein etching {HEAD ~ the second insulating layer} is stopped at the etch stopper and {TAIL ~ the surface} of the contact plug 
is stopped at
The method 1 , wherein etching { HEAD ~ the second insulating layer } is stopped at the etch stopper and { TAIL ~ the surface } of the contact plug
OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL REL REL OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH