FinFET Replacement Gate Layout for Strain and Gate Match
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Solution Overview
Problem
The scaling down of semiconductor devices presents challenges in maintaining consistent device performance due to issues with gate stack removal and subsequent strain distribution, leading to mismatches in gate resistance and capacitance.
Innovation Solution
The implementation of sacrificial gate stacks with varying lengths and the use of replacement gate structures to ensure uniform gate lengths, along with the formation of dummy gates and conductive features to stabilize strain distribution and improve device performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If gate stacks are removed during fabrication, then device scaling and integration are enabled, but strain distribution becomes inconsistent leading to gate resistance and capacitance mismatches
Solution Approach 1:
The patent uses dummy gate electrode layers as copies of functional gate electrode layers. These dummy gates are formed in openings where functional gates will be placed, allowing strain to be distributed uniformly across the semiconductor fin structure. The dummy gates replicate the mechanical properties of functional gates without requiring complex interconnect structures, thereby maintaining gate resistance and capacitance matches while enabling device integration.
Solution Approach 2:
The patent modifies the physical parameters of the gate structure by varying the lengths of dummy gate electrode layers relative to functional gate electrode layers. By adjusting these parameters, the strain distribution across the semiconductor fin is optimized to achieve consistent gate resistance and capacitance values across all devices in the integrated circuit.
2Productivity
If device geometry is scaled down, then production efficiency increases and costs decrease, but maintaining consistent device performance becomes difficult
Solution Approach 1:
The patent employs dummy gate electrode layers that are substantially identical in material composition and structural properties to functional gate electrode layers. This homogeneity ensures that strain is distributed uniformly across the semiconductor fin structure, maintaining consistent device performance characteristics across scaled-down geometries and enabling reliable mass production.
3Stability of the object's composition
If dummy gate electrode layers are formed with varying lengths, then strain distribution is stabilized, but device structure complexity increases
Solution Approach 1:
The patent divides the gate electrode structure into functional segments (active gates) and dummy segments (inactive gates with varying lengths). Each segment serves a specific purpose: functional gates provide electrical control while dummy gates of different lengths distribute strain uniformly across the semiconductor fin. This segmentation allows complex strain management without requiring overall structural complexity.
Data Source
AI summary
A semiconductor device structure, along with methods of forming such, are described. The semiconductor device structure includes an active region, and the active region includes a fin extending over a substrate, a first dummy gate electrode layer disposed over the fin, a second dummy gate electrode layer adjacent the first dummy gate electrode layer, a third dummy gate electrode layer disposed over the fin and a fourth dummy gate electrode layer adjacent the third dummy gate electrode layer. The second and third dummy gate electrode layers are disposed between the first and fourth dummy gate electrode layers. The active region further includes an active gate electrode layer disposed over the fin, and the active gate electrode layer is disposed between the second and third dummy gate electrode layers.