Interconnect Gap Structure for Lower Capacitance in Semiconductor Wiring

The patent divides the gap formation process into two distinct stages: first forming a preliminary gap structure using non-conformal deposition, then completing the gap formation by filling the space between wiring lines with additional deposit. This segmentation allows the process to handle both short and long distance wiring lines effectively, as each stage addresses specific requirements that the other cannot satisfy alone.

The patent performs preliminary gap formation by placing deposits above the wiring lines using non-conformal deposition before filling the space between wiring lines. This preliminary action creates a foundation structure that facilitates subsequent complete gap formation, particularly for wiring lines with varying distances, by pre-establishing the gap geometry in areas where it is most needed.

The patent creates a universal gap formation method that can be applied to any wiring layout regardless of line distance by combining non-conformal deposition with subsequent space filling. The non-conformal deposition step universally places deposits above all wiring lines, and the subsequent filling step universally completes the gap formation, making the process adaptable to short-distance, long-distance, and mixed-distance wiring configurations alike.

The patent applies different deposition characteristics to different regions: non-conformal deposition places thicker deposits above wiring lines where gaps are needed, while the subsequent filling step uniformly fills the spaces between lines. This local quality approach ensures consistent gap formation whether the wiring lines are close together or far apart, as each region receives the appropriate amount of material.