Liner-Free Via Interface Structure for Lower Interconnect Resistance

The patent applies local quality by selectively removing the liner layer only from the via interface region while preserving it in other areas. The subtractive patterning process creates a spatially differentiated structure where the liner layer is present in some locations (providing reliability) but absent in the via interface region (reducing resistance). This localized modification resolves the contradiction by optimizing the liner layer distribution rather than uniformly applying or removing it throughout the interconnect structure.

The patent employs preliminary action by first forming the liner layer across the entire interconnect structure before selectively removing it from the via interface region. This approach allows the liner layer to be initially deposited in a simple, uniform manner, and then the subtractive patterning process selectively removes it only where needed. The preliminary formation simplifies the overall manufacturing process compared to attempting to selectively deposit the liner layer only in specific regions from the outset.