Dielectric Fin Structure for Dense GAA Semiconductor Gates
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Solution Overview
Problem
The challenge in the semiconductor industry is to form reliable semiconductor devices as feature sizes continue to decrease, making fabrication processes increasingly difficult.
Innovation Solution
The solution involves forming FinFET structures with fins patterned using photolithography processes like double-patterning or multi-patterning, and gate all around (GAA) transistor structures, along with the use of sacrificial layers and epitaxial growth to create semiconductor nanostructures and dielectric fins that help in reducing the spacing between fin structures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If feature sizes continue to decrease to increase functional density, then production efficiency increases and costs decrease, but fabrication process complexity and difficulty increase
Solution Approach 1:
The fabrication process is divided into multiple patterning steps (double-patterning, multi-patterning) where each step creates a portion of the final pattern. This segmentation allows achieving smaller feature sizes with controlled complexity at each individual step rather than attempting to create all features in a single complex process.
Solution Approach 2:
Sacrificial layers are formed in advance before the final device structure is created. These preliminary structures guide the formation of fins and other features, and are removed later. This preliminary action simplifies the overall process by providing templates that make subsequent steps more straightforward.
2Productivity
If feature sizes continue to decrease to increase functional density, then production efficiency increases and costs decrease, but manufacturing reliability decreases
Solution Approach 1:
Dielectric structures are formed beforehand to provide mechanical support and isolation for the smaller, more fragile features. These cushioning structures protect the delicate fin structures during subsequent processing steps, maintaining manufacturing reliability even as feature sizes decrease.
Solution Approach 2:
Different regions of the device use different materials and structures optimized for their specific functions. For example, dielectric materials with specific properties are placed in specific locations to provide local support, isolation, or electrical properties, ensuring reliability of individual components while maintaining overall small dimensions.
3Quantity of substance
If spacing between fin structures is reduced to increase device density, then device density increases, but fabrication precision requirements increase
Solution Approach 1:
Dielectric structures serve as intermediary elements between adjacent fin structures. These intermediary dielectric regions act as spacers and isolation barriers, defining the spacing between fins with precision determined by the dielectric layer deposition rather than direct fin patterning, thereby reducing the precision demands on the fin formation process itself.
4Quantity of substance
If spacing between fin structures is reduced to increase device density, then device density increases, but fabrication difficulty increases
Solution Approach 1:
The dielectric structures perform multiple functions simultaneously: they provide electrical isolation between adjacent fins, serve as spacers to define fin spacing, offer mechanical support during processing, and act as etch stop layers. This multi-functionality reduces the need for separate structures, simplifying the overall fabrication process while maintaining high device density.
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 allows for the formation of semiconductor devices with increased device density, reduced fabrication costs, and improved reliability by minimizing the spacing between fin structures and enhancing the performance and reliability of the semiconductor device structure.
Implementation Method 1
fins patterned using photolithography processes like double-patterning or multi-patterning
Implementation Method 2
use of sacrificial layers and epitaxial growth to create semiconductor nanostructures
Data Source
AI summary
A semiconductor device structure is provided. The semiconductor device structure includes multiple first semiconductor nanostructures over a substrate and multiple second semiconductor nanostructures over the substrate. The semiconductor device structure also includes a dielectric structure between the first semiconductor nanostructures and the second semiconductor nanostructures. The semiconductor device structure further includes a metal gate stack wrapped around the first semiconductor nanostructures and the second semiconductor nanostructures. The metal gate stack has a gate dielectric layer and a gate electrode. The gate dielectric layer extends along a sidewall of a lower portion of the dielectric structure. A topmost surface of the gate dielectric layer is between a topmost surface of the first semiconductor nanostructures and a topmost surface of the dielectric structure.