Patent ID: RE38914

Claim:
A method for forming a via through a dielectric layer within a microelectronics fabrication comprising: providing a substrate employed within a microelectronics fabrication, the substrate having a contact region formed therein; forming upon the substrate and covering the contact region a blanket first dielectric layer, the blanket first dielectric layer being formed of a first dielectric material which is not susceptible to etching with an oxygen containing plasma; forming upon the blanket first dielectric layer a blanket second dielectric layer, the blanket second dielectric layer being formed of a second dielectric material which is susceptible to etching within the oxygen containing plasma; forming upon the blanket second dielectric layer a blanket hard mask layer, the blanket hard mask layer being formed from a hard mask material which is not susceptible to etching within the oxygen containing plasma; forming upon the blanket hard mask layer a patterned first photoresist layer, the patterned first photoresist layer leaving 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; etching, 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 while employing the patterned first photoresist layer as a first etch mask layer, the first plasma etch method employing a first etchant gas composition appropriate to the hard mask material from which is formed the blanket hard mask layer; etching, while employing a second plasma etch method and at least the patterned hard mask layer as a second etch mask layer, the blanket second dielectric layer, and simultaneously stripping the patterned first photoresist layer, to form a patterned second dielectric layer having a second trench formed therethrough at a location corresponding with the first trench formed through the blanket hard mask layer, the second plasma etch method employing the oxygen containing plasma; the second plasma etch not etching the blanket first dielectric layer; forming 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, the areal deminsion of the via being contained within the areal deminsion of the second trench; and etching, 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, the third plasma etch method employing a third etchant gas composition appropriate to the first dielectric material.