Single Fin Transistor Stress Management via Insulating Spacer Gap
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Solution Overview
Problem
Traditional manufacturing processes for forming single-fin FinFET and vertical transistor devices often result in undesirable crystalline defects due to lateral stress caused by the contraction of flowable oxide materials during anneal processes, which can reduce the performance capabilities of these devices.
Innovation Solution
A method involving the formation of a single semiconductor structure in a semiconductor substrate, with a liner layer and insulating materials, followed by an etching process to create a gap and an insulating sidewall spacer, which reduces the stress on the semiconductor structure by limiting the contraction of the second insulating material layer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If flowable oxide material is formed and annealed to overfill trenches adjacent the fin, then the trench is properly filled and isolated, but the material contracts and exerts lateral stress on the fin causing crystalline defects
Solution Approach 1:
The patent segments the insulating material into two distinct layers: a first insulating material layer with high density formed at the bottom of the trench, and a second flowable oxide material layer formed above it. This segmentation allows the high-density first layer to provide structural support and resist contraction stresses, while the second layer maintains its flowable properties for proper trench filling. The etching process selectively removes portions of the second layer not covered by the first layer, creating a gap that prevents stress transmission to the fin structure.
Solution Approach 2:
The patent applies different material properties to different regions of the trench structure. The first insulating material layer is specifically positioned at the bottom of the trench where structural support is most critical, providing high density and stress resistance. The second flowable oxide material layer is positioned above it where flowability and conformal coverage are needed. This local differentiation of material properties optimizes both trench filling quality and stress management.
2Use of energy by moving object
If a single fin structure is used to reduce power consumption, then power efficiency is improved, but the fin is more susceptible to stress-induced crystalline defects
Solution Approach 1:
The patent implements a cushioning structure by forming the first high-density insulating material layer at the bottom of the trench before forming the second flowable oxide layer. This first layer acts as a cushioning layer that absorbs and distributes contraction stresses from the second layer, preventing these stresses from being transmitted to the single fin structure. The etching process creates a gap between the second layer and the fin, further isolating the fin from stress. This beforehand cushioning protects the power-efficient single fin structure from stress-induced defects.
3Stability of the object's composition
If anneal processes are performed to cure the flowable oxide material, then the material is properly formed and stable, but the material contracts and exerts stress on the semiconductor structure
Solution Approach 1:
The patent extracts portions of the second flowable oxide material layer through the etching process, specifically removing portions that are not covered by the first insulating material layer. This extraction creates a gap between the second layer and the fin structure, isolating the second layer from the fin. The anneal-induced contraction of the second layer is thus absorbed by this gap rather than being transmitted as lateral stress to the fin, while the second layer maintains its stability and proper formation.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach minimizes the formation of crystalline defects by distributing the stress across a higher-density first insulating material layer, thereby enhancing the performance and reliability of single-fin FinFET and vertical transistor devices.
Implementation Method 1
performing an etching process to remove portions of the liner layer of material not covered by the first insulating material
Implementation Method 2
the one or more anneal processes cause the flowable oxide material to contract, which exerts a lateral or horizontal stress on the fin
Data Source
AI summary
A transistor device that includes a single semiconductor structure having an outer perimeter and a vertical height, wherein the single semiconductor structure is at least partially defined by a trench formed in a semiconductor substrate and a first layer of material positioned on the bottom surface of the trench and around the outer perimeter of the single semiconductor structure. The device also includes a second layer of material positioned on the first layer of material and around the outer perimeter of the single semiconductor structure, a gap between the outer perimeter of the single semiconductor structure and both the first and second layers of material (when considered collectively) and an insulating sidewall spacer positioned in the gap, wherein the insulating sidewall spacer has a vertical height that is less than the vertical height of the single semiconductor structure.