GAA Semiconductor Structure With Low-k Dielectric Wall Isolation
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Solution Overview
Problem
The integration of multi-gate devices in semiconductor manufacturing is challenging due to increased complexity and the need for advanced processes to achieve improved gate control, reduced OFF-state current, and minimized short-channel effects while maintaining low-power and high-performance integrated circuits.
Innovation Solution
The implementation of gate-all-around (GAA) transistor structures with a dielectric wall made of low-k material, formed using double-patterning or multi-patterning processes, to enhance gate-channel coupling and reduce capacitance, involves forming fin structures, dummy gate structures, and spacers, followed by the removal of dummy gates and isolation material to create a planar surface for subsequent gate formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multi-gate devices are integrated to improve gate control and reduce short-channel effects, then device performance is improved, but manufacturing complexity increases
Solution Approach 1:
The manufacturing process is divided into multiple discrete stages including forming first and second fin structures, selective removal of semiconductor material layers, formation of dielectric walls, and sequential gate structure formation. This segmentation allows complex multi-gate devices to be manufactured through manageable, repeatable process steps that reduce overall manufacturing complexity while maintaining improved gate control.
Solution Approach 2:
Dummy gate structures are formed early in the process on both first and second fin structures before the actual gate structure is created. These preliminary dummy gates serve as placeholders that guide subsequent processing steps, including dielectric wall formation and material removal, ultimately simplifying the manufacturing of the final multi-gate device configuration.
2Productivity
If device dimensions are scaled down to improve production efficiency and lower costs, then productivity is improved, but manufacturing complexity increases
Solution Approach 1:
The structure employs nested configurations where first fin structures and second fin structures are positioned in close proximity, dielectric walls are formed within recesses between fins, and gate structures envelop multiple fin structures. This nesting approach allows high-density integration of scaled-down devices while using systematic process steps that maintain manufacturing efficiency despite increased device complexity.
3Reliability
If dielectric walls are formed between fin structures to reduce capacitance, then gate control is improved, but manufacturing precision requirements increase
Solution Approach 1:
Dummy gate structures serve as intermediary elements that define the precise locations where dielectric walls will be formed. The dummy gates are removed after guiding the dielectric wall formation process, ensuring accurate positioning and spacing of dielectric walls between fin structures without requiring direct precision control in the final gate formation step.
Solution Approach 2:
The process replaces direct mechanical precision requirements with chemical and physical processes. Conformal deposition of dielectric materials followed by anisotropic etching and selective removal processes substitute for purely mechanical positioning methods, allowing precise dielectric wall formation with relaxed mechanical alignment tolerances.
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 improves the performance of semiconductor structures by reducing capacitance and enhancing gate control, thereby addressing the challenges of multi-gate device integration and maintaining low-power consumption.
Implementation Method 1
The dielectric wall is made of low-k dielectric material to reduce the capacitance of the semiconductor structure
Data Source
AI summary
Semiconductor structures and methods for manufacturing the same are provided. The semiconductor structure includes an isolation structure formed over a substrate, and first nanostructures formed over an isolation structure along a first direction. The semiconductor includes second nanostructures adjacent to the first nanostructure along the first direction. The semiconductor also includes a dielectric wall between the first nanostructures and the second nanostructures, and the dielectric wall includes a low-k dielectric material. The dielectric wall is in direct contact with the first nanostructures and the second nanostructures, and a top surface of the dielectric wall is higher than a top surface of the isolation structure. The semiconductor includes a gate structure formed over the first nanostructures along a second direction, and a cutting structure formed over the dielectric wall. The gate structure is divided into two portions by the cutting structure.