Semiconductor Fin Gate Layout Using Dielectric Dummy Fin Isolation
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Solution Overview
Problem
In the semiconductor industry, the increasing number of gate structures to be cut during transistor fabrication leads to discrepancies in profiles and dimensions, causing undesired connections between gate structures and source/drain regions, particularly when the number exceeds a threshold, constraining the flexibility of integrated circuit design.
Innovation Solution
The method involves forming dummy fin structures between active regions before gate structure formation, with these dummy fins being taller than active fins and having a top surface coplanar with the later-formed gate structures, allowing for spontaneous cutting of gate structures into distinct portions, thereby avoiding discrepancies and enabling flexible design.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the number of gate structures to be cut exceeds a threshold, then the integration density increases, but the profile and dimension discrepancies among gate structures lead to undesired connections with source/drain regions or contacts
Solution Approach 1:
The patent introduces dummy fin structures that segment the continuous gate structure into separate portions. These dummy fins act as physical barriers that prevent the gate structure from forming undesired connections with source/drain regions or contacts, thereby maintaining manufacturing precision while allowing higher integration density.
Solution Approach 2:
The dummy fin structures serve as intermediary elements between the gate structures and source/drain regions. By placing these dummy fins at strategic locations, the patent prevents direct contact between the gate and source/drain, eliminating the harmful connections that occur when gate structures are cut excessively.
2Adaptability or versatility
If gate structures are cut to increase design flexibility, then circuit design freedom improves, but profile discrepancies cause undesired connections with source/drain regions
Solution Approach 1:
By segmenting the gate structure using dummy fin structures, the patent enables designers to create flexible circuit layouts without risking undesired connections. The segmentation occurs at the dummy fin locations, which are strategically placed to prevent harmful connections while allowing design freedom.
Solution Approach 2:
The dummy fin structures are formed in advance before the gate structure is deposited. This preliminary action ensures that when the gate structure is later formed and potentially cut, the dummy fins are already in place to prevent undesired connections with source/drain regions or contacts.
3Productivity
If more gate structures are formed to increase integration density, then the number of components increases, but the complexity of maintaining consistent profiles and dimensions increases
Solution Approach 1:
The patent merges the formation of dummy fin structures with the existing fin formation process. By using the same epitaxial growth and etching processes for both active fins and dummy fins, the patent increases integration density without proportionally increasing fabrication complexity.
Solution Approach 2:
The dummy fin structures serve multiple functions: they act as spacers during gate formation, prevent undesired connections, and maintain profile consistency. This multi-functionality reduces the need for additional specialized process steps, thereby limiting the increase in fabrication complexity.
Data Source
AI summary
A semiconductor device includes a first semiconductor fin extending along a first direction. The semiconductor device includes a second semiconductor fin also extending along the first direction. The semiconductor device includes a dielectric fin disposed between the first and second semiconductor fins, wherein the dielectric fin also extends along the first direction. The semiconductor device includes a gate structure extending along a second direction perpendicular to the first direction, the gate structure comprising a first portion and a second portion. A top surface of the dielectric fin is vertically above respective top surfaces of the first and second semiconductor fins. The first portion and the second portion are electrically isolated by the dielectric fin. The first portion of the gate structure overlays an edge portion of the first semiconductor fin, and the second portion of the gate structure overlays a non-edge portion of the second semiconductor fin.