The substrate has a first surface and {HEAD ~ a second surface} spaced in {TAIL ~ a predetermined interval} apart from the first surface is prepared 
spaced in
The substrate has a first surface and { HEAD ~ a second surface } spaced in { TAIL ~ a predetermined interval } apart from the first surface is prepared
OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH