GAA Semiconductor Structure With Inner Spacers for Tighter Gate Pitch

The gate structure formation is divided into multiple stages: first forming a sacrificial layer with initial gate patterns, then using spacer deposition to create additional gate structures between the sacrificial layers. This segmentation allows gate structures to be formed without requiring large lithography processing spaces, as the spacer-based approach uses self-aligned processes that need minimal additional lithography space.

The patent transitions from planar gate formation to three-dimensional gate-all-around structures by depositing spacers vertically on the sidewalls of sacrificial layers. This dimensional transition enables compact device footprints while maintaining precise gate alignment, as the vertical spacer deposition process requires minimal lateral space compared to traditional lithography approaches.

The patent deposits spacer layers on the sidewalls of sacrificial gate structures before performing etching operations. These spacers act as protective cushions that prevent etchant from directly contacting and damaging the gate structures during side-etching processes, enabling safe reduction of spacing between adjacent gate structures to increase transistor density.

The spacer structures serve as intermediary protective elements between the etchant and the gate structures. During manufacturing processes that require side-etching, the spacers mediate the interaction by absorbing or redirecting the etchant away from the gate structures, thereby preventing damage while allowing closely spaced gate structures for high-density transistors.