A method for forming a via through a dielectric layer within a microelectronics
fabrication. There is first provided a substrate having a contact region formed
therein. There is then formed upon the substrate and covering the contact region
a blanket first dielectric layer formed of a first dielectric material which is
not susceptible to etching with an oxygen containing plasma. There is then formed
upon the blanket first dielectric layer a blanket second dielectric layer formed
of a second dielectric material which is susceptible to etching within the oxygen
containing plasma. There is then formed upon the blanket second dielectric layer
a blanket hard mask layer formed from a hard mask material which is not susceptible
to etching within the oxygen containing plasma. There is then formed upon the blanket
hard mask layer a patterned first photoresist layer which leaves exposed a portion
of the blanket hard mask layer greater than and completely overlapping an areal
deminsion of a via to be formed through the blanket first dielectric layer to access
the contact layer. There is then etched while employing a first plasma etch method
the blanket hard mask layer to form a patterned hard mask layer defining a first
trench formed through the patterned hard mask layer. There is then etched while
employing a second plasma etch method and at least the patterned hard mask layer
the blanket second dielectric layer to form a patterned second dielectric layer
having a second trench formed therethrough, where the second plasma etch method
employs the oxygen containing plasma which preferably simultaneously strips the
patterned first photoresist layer. There is then formed over at least the patterned
second dielectric layer a patterned second photoresist layer which defines the
location of the via to be formed through the blanket first dielectric layer. There
is then etched while employing a third plasma etch method and the patterned second
photoresist layer as a third etch mask layer the via through the blanket first
dielectric layer.