NOVELTY - Formation of a trench contiguous with a via through a dielectric layer comprises ion-implanting into exposed portion of blanket hard mask layer and into portion of blanket second dielectric layer aligned beneath the exposed portion. The ion implanted portion of the blanket second dielectric layer has an enhanced etch rate within the oxygen-containing plasma.    USE - The method forms a trench contiguous with a via through a dielectric layer, particularly a patterned conductor interconnect layer contiguous with a patterned conductor stud layer. It is useful in micro-electronics fabrication, e.g. semiconductor integrated circuit micro-electronics fabrication, solar cell micro-electronics fabrication, ceramic substrate micro-electronics fabrication, and flat panel display micro-electronics fabrication.    ADVANTAGE - By ion implanting the portions of the blanket hard mask layer and the blanket second dielectric layer, the aperture is formed with enhanced linewidth control. The method also attenuates process complexity.    DETAILED DESCRIPTION - Forming a trench contiguous with a via through a dielectric layer comprises providing a substrate (10) having a contact region (12a-12c). A patterned first dielectric layer (14a-14d) is formed upon the substrate to define a via accessing the contact region. It is formed of a first dielectric material which is not susceptible to etching with an oxygen-containing plasma. A blanket second dielectric layer is formed to completely cover the patterned first dielectric later and fill the via. It is formed of a second dielectric material which is susceptible to etching within the oxygen-containing plasma. A blanket hard mask layer formed from a hard mask material which is not susceptible to etching within the oxygen-containing plasma is formed upon the blanket second dielectric layer. A patterned photoresist layer (20a-20d) is formed upon the blanket hard mask layer to provide an exposed portion of the blanket hard mask layer greater than an areal dimension of the via and at least partially overlapping the areal dimension of the via. A dose of an ion is implanted into the exposed portion of the blanket hard mask layer and into a portion of the blanket second dielectric layer aligned beneath the exposed portion of the blanket hard mask layer. The ion implanted portion of the blanket second dielectric layer (16') has an enhanced etch rate within the oxygen-containing plasma compared with a non-ion implanted portion of the blanket second dielectric layer. The ion implanted portion of the blanket hard mask layer is etched, while employing a first plasma (22) etch, to form a patterned hard mask layer (18a-18d) defining a first trench formed through the patterned hard mask layer while employing the patterned photoresist layer as a first etch mask layer. The first plasma etch employs a first etchant gas composition for the ion implanted portion of the blanket hard mask layer. The blanket second dielectric layer is etched, while performing a second plasma etch, to form a patterned second dielectric layer having an aperture comprising a second trench corresponding with the first trench and at least a portion of the via. The second plasma etch employs the oxygen-containing plasma.    DESCRIPTION OF DRAWING(S) - The figure is a schematic cross-sectional diagram showing the results of forming within a micro-electronics fabrication two series of dielectric layers.    Substrate (10)    Contact region (12a-12c)    Patterned first dielectric layer (14a-14d)    Ion implanted blanket second dielectric layer (16')    Patterned hard mask layer (18a-18d)    Patterned photoresist layer (20a-20d)    First plasma (22)