FinFET Fin Width Control via Selective Oxidation
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Solution Overview
Problem
Conventional methods for forming fins with different widths in FinFET devices are complex and inefficient, affecting the control of channel current and leakage in semiconductor transistors.
Innovation Solution
A semiconductor fabrication method involving the formation of fins with varying widths using a first barrier layer and an oxygen-containing annealing process to oxidize sidewalls, reducing fin widths in specific regions while maintaining larger widths in others, with the aid of mask layers and subsequent etching processes to control oxidation rates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If conventional methods are used to form fins with different widths, then fin width variation can be achieved, but the fabrication process becomes complicated and inefficient
Solution Approach 1:
The patent applies local quality by forming a first barrier layer selectively on fins in the first region but not on fins in the second region, and by using an isolation fluid layer that covers only specific regions. This allows different fin widths to be formed in different regions through localized oxidation during annealing, achieving width variation without complicating the overall fabrication process
Solution Approach 2:
The patent introduces an isolation fluid layer as an intermediary substance that selectively covers fins in the second region during annealing. This isolation fluid acts as a mask that prevents oxidation of fins in the second region while allowing oxidation of fins in the first region, thereby achieving different fin widths through a single annealing process rather than multiple etching steps
2Manufacturing precision
If fin width is reduced to reduce short-channel effect, then channel current control improves, but fabrication complexity increases
Solution Approach 1:
The patent forms a first barrier layer selectively on fins in the first region where wider fins are desired, while leaving fins in the second region exposed. During annealing, this creates localized oxidation that reduces fin width only in the second region, enabling precise control of channel dimensions without requiring complex multi-step patterning processes
Solution Approach 2:
The patent changes the physical and chemical parameters of the fin structure through thermal annealing in an oxygen-containing atmosphere. The barrier layer and isolation fluid create different oxidation environments, causing controlled oxidation that reduces fin width in specific regions, thereby achieving precise dimensional control through parameter changes rather than mechanical etching
3Manufacturing precision
If multiple processes are used to form fins with different widths, then width precision can be controlled, but manufacturing efficiency decreases
Solution Approach 1:
The patent merges the functions of multiple patterning and etching processes into a single annealing step. By combining the barrier layer formation, isolation fluid deposition, and thermal oxidation into one integrated process sequence, the patent achieves different fin widths across regions without requiring separate etching steps for each width, thereby maintaining precision while improving manufacturing efficiency
Solution Approach 2:
The isolation fluid layer serves as an intermediary that enables single-step width differentiation. Instead of using multiple etching processes with different masks, the isolation fluid acts as a temporary protective layer during annealing, allowing the oxidation process to selectively reduce fin widths in regions without the isolation fluid, thereby achieving precise width control in a single process step
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
Simplifies the fabrication process by controlling fin widths effectively, reducing the complexity of fin formation and improving the control of channel current and leakage in semiconductor devices.
Implementation Method 1
forming an isolation film and a by-product layer by an oxygen-containing annealing process respectively from the isolation fluid layer and sidewalls of the fins in the second region
Data Source
AI summary
A semiconductor device and a method for fabricating the semiconductor device are provided. The method includes providing a semiconductor substrate including a first region and a second region, and forming a plurality of fins on the semiconductor substrate in the first region and the second region. The method also includes forming a first barrier layer on surfaces of the fins in the first region, and forming an isolation fluid layer on the semiconductor substrate to cover the first barrier layer in the first region and to cover the fins in the second region. Further, the method includes forming an isolation film and a by-product layer by an oxygen-containing annealing process respectively from the isolation fluid layer and sidewalls of the fins in the second region.