Sidewall Double Patterning for H-Shaped Wiring Layouts

The patent segments the pattern formation process into multiple steps: first forming mandrels at relaxed pitch, then using sidewalls as masks to define final patterns at higher density. This segmentation allows the lithography step to work at lower resolution while the sidewall self-alignment provides the final high-precision patterning, thereby maintaining design freedom despite resolution constraints.

The patent introduces sidewalls as an intermediary element between the mandrel and the final pattern. The sidewall acts as a self-aligned mask that translates the relaxed-pitch mandrel structure into high-density final patterns. This intermediary enables the system to overcome direct lithography resolution limits while preserving layout flexibility through controlled sidewall formation and mandrel removal.

The patent employs dynamic control of the mandrel structure, allowing mandrels to be selectively removed in certain regions while retained in others. This dynamic approach enables the formation of H-shaped patterns where sidewalls from adjacent mandrels create the horizontal connecting bar, while vertical segments are formed by retained mandrels. The system transitions from static single-pattern formation to dynamic multi-stage pattern creation.

The patent utilizes the vertical dimension by forming sidewalls that extend perpendicular to the substrate surface. These vertical sidewalls serve as three-dimensional masks that can define horizontal pattern connections when viewed from the top. This dimensional transition allows H-shaped patterns to be formed through sidewall interactions rather than direct planar lithography, enabling complex 2D patterns via 3D structure manipulation.