FPGA Lookup Table Decoder Layout With Angled Fins and Backside Power

The patent transitions from planar 2D transistor layouts to three-dimensional FinFET structures with vertical fins extending from the substrate. This dimensional change allows current flow paths to extend vertically rather than only laterally, enabling higher device density without proportionally increasing lithographic complexity. The fin structures can be formed using self-aligned processes where the fin width is defined by etch geometry rather than direct lithographic patterning.

The patent replaces direct lithographic patterning of transistor gates with self-aligned fabrication processes. The fin structures are formed through selective epitaxial growth or deposition followed by anisotropic etching, where the fin dimensions are determined by mask geometry and etch parameters rather than direct optical lithography. This substitution reduces the critical dimension requirements on lithographic tools.

The FinFET structure introduces vertical current flow paths through the fin height dimension. Power and signal routing can utilize multiple metal layers at different heights above the fins, creating a three-dimensional interconnect architecture. This allows power delivery networks to distribute energy more efficiently across dense transistor arrays by utilizing vertical vias and multi-layer routing rather than relying solely on planar metal traces.

The patent implements a nested architecture where FinFET devices are embedded within isolation structures, which are in turn embedded within interconnect layers. Multiple metal interconnect layers are stacked vertically, with each layer providing additional routing capacity. This nested, multi-layer approach allows efficient power and signal distribution to high-density transistor regions without increasing the lateral footprint or compromising delivery efficiency.