Rounding Fin-Shaped Structures via Selective Oxidation
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Solution Overview
Problem
The miniaturization of semiconductor devices leads to challenges in manufacturing fin-shaped structures, particularly in achieving uniformity of layers over these structures, which affects device reliability due to tip/point effects.
Innovation Solution
A method involving the use of pad oxide and pad nitride caps covering fin-shaped structures, followed by an oxidation process to round the structures, thereby forming oxidized parts that cover the sidewalls and allowing for uniform layer deposition, specifically enhancing the reliability of devices by reducing the tip/point effect.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If fin-shaped structures are used in miniaturized semiconductor devices, then device integration and channel control are improved, but manufacturing precision deteriorates due to non-uniform layer deposition on sharp fins
Solution Approach 1:
The patent applies curvature by rounding the sharp fin structures into curved profiles. This is achieved through a multi-step process: forming pad oxide and pad nitride caps on the fins, performing selective oxidation to grow oxidized parts on exposed fin portions, and selectively removing these oxidized parts. The rounding transformation changes the fin geometry from sharp edges to curved surfaces, enabling uniform layer deposition while maintaining the underlying fin functionality.
2Device complexity
If sharp fin structures are maintained, then device structure simplicity is preserved, but device reliability deteriorates due to tip/point effects
Solution Approach 1:
The patent transforms sharp fin structures into rounded structures through selective oxidation and removal processes. The oxidation grows oxidized parts preferentially on exposed fin portions, and subsequent selective removal creates rounded profiles. This curvature eliminates tip/point effects that cause reliability issues, while the overall fin structure and device architecture remain relatively simple.
3Manufacturing precision
If oxidation process is applied to round fin structures, then layer uniformity and device reliability are improved, but manufacturing complexity increases
Solution Approach 1:
The patent segments the fin structure treatment into distinct phases: forming pad oxide and pad nitride caps, selective oxidation to grow oxidized parts, and selective removal of these oxidized parts. This segmentation allows precise control over which portions of the fin are rounded, enabling uniform layer deposition on rounded fins while managing process complexity through systematic step-by-step treatment.
Solution Approach 2:
The patent introduces pad oxide and pad nitride caps as intermediary layers that facilitate the rounding process. These caps serve as protective and selective masks during oxidation, enabling controlled growth of oxidized parts on fin surfaces. The intermediaries allow the oxidation process to be selective and controllable, achieving rounding without excessive complexity.
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
The method effectively rounds fin-shaped structures, ensuring uniformity of layers such as the work function metal layer, thereby enhancing device reliability and reducing the tip/point effect.
Implementation Method 1
An oxidation process is performed to oxidize sidewalls of the top parts of the fin-shaped structures, thereby forming oxidized parts covering the sidewalls of the top parts of the fin-shaped structures
Data Source
AI summary
A method of rounding fin-shaped structures includes the following steps. A substrate including fin-shaped structures, and pad oxide caps and pad nitride caps covering the fin-shaped structures from bottom to top are provided. An isolation structure fills between the fin-shaped structures. A removing process is performed to remove a top part of the isolation structure and expose top parts of the fin-shaped structures. An oxidation process is performed to oxidize sidewalls of the top parts of the fin-shaped structures, thereby forming oxidized parts covering sidewalls of the top parts of the fin-shaped structures. The pad nitride caps are removed. The pad oxide caps and the oxidized parts are removed at the same time, thereby forming rounding fin-shaped structures.