Multi-Stack Semiconductor Layout With Overlapping Via Rails

The patent introduces a vertical dimension by implementing via rails that extend in the vertical direction to overlap with power rails. This dimensional transition allows the contact area to be increased from a two-dimensional planar contact to a three-dimensional overlapping structure, thereby reducing electrical resistance while managing the added structural complexity through spatial optimization.

The via rails are positioned to overlap and nest with the power rails in the vertical direction, creating a nested configuration where the via rail structure is integrated within the vertical space above the power rail. This nesting approach maximizes the contact area without proportionally increasing the horizontal footprint, thus reducing resistance while controlling overall device complexity.

Instead of extending via rails only in the horizontal direction which would require precise horizontal alignment, the patent transitions to the vertical dimension by creating overlapping structures. This vertical extension reduces the sensitivity to horizontal alignment precision while still achieving increased contact area, thereby lowering manufacturing precision requirements.

The patent merges the via rail structure with the power rail structure by positioning them to overlap in the vertical direction. This merging creates a combined structure where the contact area is increased through vertical integration rather than horizontal extension, reducing the stringency of horizontal alignment precision requirements during manufacturing.