Asymmetric Gate Isolation Wall Layout for Multi-Gate Nanostructures
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Solution Overview
Problem
The integration of multi-gate devices in semiconductor manufacturing is challenging due to complexity and the need for improved gate control, reduced OFF-state current, and reduced short-channel effects, while maintaining manufacturing efficiency and reducing parasitic capacitance.
Innovation Solution
A semiconductor structure with asymmetric gate structures and isolation walls is formed using double-patterning or multi-patterning processes, where the distance between the sidewall surfaces of the nanostructures and isolation walls is varied to minimize damage during etching and reduce parasitic capacitance, enhancing performance and yield.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multi-gate devices are integrated to improve gate control and reduce short-channel effects, then device performance is improved, but manufacturing complexity increases
Solution Approach 1:
The gate structure is segmented into multiple gates (first gate structure and second gate structure) that wrap around the channel from opposite directions. This segmentation enables improved gate control and reduced short-channel effects while allowing each gate to be formed through separate, standardized fabrication processes, thereby managing manufacturing complexity through modular construction
Solution Approach 2:
The patent employs asymmetric positioning of isolation walls relative to the two gates, with the first isolation wall positioned at a first distance from the first gate and the second isolation wall positioned at a second distance from the second gate. This asymmetric design optimizes electrical performance and gate control while accommodating the specific manufacturing constraints of forming multi-gate structures
2Productivity
If feature sizes are reduced to improve production efficiency, then productivity is improved, but manufacturing precision requirements increase
Solution Approach 1:
The patent applies different spacing configurations in different locations: the first distance between the first gate and first isolation wall is different from the second distance between the second gate and second isolation wall. This local differentiation allows optimization of electrical performance in each region while maintaining overall manufacturing feasibility with reduced feature sizes
Solution Approach 2:
Isolation walls are formed prior to the final gate formation steps, establishing predetermined spacing and alignment references that guide subsequent manufacturing processes. This preliminary action ensures that even with reduced feature sizes, the required precision is maintained through pre-established geometric constraints
3Object-generated harmful factors
If isolation walls are positioned closer to reduce parasitic capacitance, then electrical performance is improved, but gate structure damage risk increases
Solution Approach 1:
The patent positions the first isolation wall at a first distance from the first gate structure and the second isolation wall at a second distance from the second gate structure, where these distances are intentionally different. This asymmetric configuration allows each gate-isolation wall pair to be optimized independently, balancing parasitic capacitance reduction with mechanical protection against etching damage
Solution Approach 2:
The patent varies the spacing parameters (first distance and second distance) as design variables to optimize the balance between electrical performance and structural integrity. By treating these distances as adjustable parameters rather than fixed values, the design can be tuned to achieve minimal parasitic capacitance while maintaining sufficient clearance to prevent gate damage during fabrication
Data Source
AI summary
Semiconductor structures and methods for manufacturing the same are provided. The semiconductor structure includes first nanostructures and second nanostructures formed over the substrate along the first direction. The semiconductor structure includes a first gate structure formed over the first nanostructures along a second direction, and a second gate structure formed over the second nanostructures. The semiconductor structure includes an isolation wall structure between the first gate structure and the second gate structure, and the isolation wall structure has a first sidewall surface and a second sidewall surface. There is a first distance between the sidewall surface of the topmost first nanostructure and the first sidewall surface of the isolation wall structure, and there is a second distance between a sidewall surface of the topmost first nanostructure and the second sidewall surface of the isolation wall structure. The first distance is greater than the second distance.