Hybrid Fin Isolation Structure for Void-Free FinFET Spacing
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Solution Overview
Problem
As semiconductor devices shrink, the reduced separation between laterally adjacent fin structures leads to voids in hybrid fins, degrading electrical isolation and increasing parasitic capacitance, which affects the yield and performance of integrated circuits.
Innovation Solution
A hybrid fin isolation structure is formed with a lower portion made of a low-k dielectric material and an upper portion made of a high-k dielectric material, including a metal element like hafnium and oxygen, which is selectively etched to connect gate metal lines without voids, ensuring seamless isolation between fin structures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the separation between laterally adjacent fin structures is reduced to increase device density, then the storage capacity and processing speed are improved, but voids form in hybrid fins which degrades electrical isolation and increases parasitic capacitance
Solution Approach 1:
The isolation structure is divided into two distinct segments: a lower portion made of a first dielectric material and an upper portion made of a second dielectric material. This segmentation allows each material to be optimized for its specific function - the lower portion provides mechanical support and baseline isolation, while the upper portion provides enhanced electrical isolation with lower parasitic capacitance, thereby resolving the contradiction between maintaining isolation quality and reducing device dimensions.
Solution Approach 2:
Different dielectric materials are applied to different regions of the isolation structure based on local requirements. The lower portion uses a dielectric material optimized for mechanical integrity and stress management, while the upper portion uses a dielectric material with superior electrical isolation properties. This local differentiation enables the structure to simultaneously satisfy mechanical support requirements and electrical isolation requirements in closely spaced fin structures.
2Productivity
If the separation between laterally adjacent fin structures is reduced to increase device density, then the storage capacity and processing speed are improved, but parasitic capacitance increases which degrades performance
Solution Approach 1:
The isolation structure is divided into two distinct segments: a lower portion made of a first dielectric material and an upper portion made of a second dielectric material. This segmentation allows each material to be optimized for its specific function - the lower portion provides mechanical support and baseline isolation, while the upper portion provides enhanced electrical isolation with lower parasitic capacitance, thereby resolving the contradiction between maintaining isolation quality and reducing device dimensions.
Solution Approach 2:
The dielectric constant parameter is varied through the height of the isolation structure. The lower portion uses a dielectric material with one constant value optimized for mechanical properties, while the upper portion uses a dielectric material with a different constant value optimized for minimizing parasitic capacitance. This parameter change through the structure height enables simultaneous optimization of mechanical support and electrical isolation performance.
3Ease of manufacture
If conventional isolation structures are used in scaled devices, then manufacturing simplicity is maintained, but voids form in hybrid fins which degrades yield
Solution Approach 1:
The isolation structure is divided into two distinct segments: a lower portion made of a first dielectric material and an upper portion made of a second dielectric material. This segmentation allows each material to be optimized for its specific function - the lower portion provides mechanical support and baseline isolation, while the upper portion provides enhanced electrical isolation with lower parasitic capacitance, thereby resolving the contradiction between maintaining isolation quality and reducing device dimensions.
Solution Approach 2:
The isolation structure employs a composite of two different dielectric materials, each contributing unique properties. The first dielectric material in the lower portion provides mechanical integrity and stress management, while the second dielectric material in the upper portion provides superior electrical isolation. This composite approach enables the structure to achieve both mechanical robustness and electrical performance without forming voids, even in closely spaced fin structures.
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 solution effectively reduces voids in the isolation structure, enhancing electrical isolation and reducing parasitic capacitance, thereby improving the yield and performance of integrated circuits by maintaining sufficient electrical isolation and mechanical integrity.
Implementation Method 1
performing a spin-coating process to coat a flowable oxide material over the first layer of dielectric material
Implementation Method 2
The process of spin-coating can further include annealing the coated flowable oxide material to form a second layer of dielectric material that contains silicon-metal-oxide
Implementation Method 3
A hybrid fin isolation structure is formed with a lower portion made of a low-k dielectric material and an upper portion made of a high-k dielectric material
Data Source
AI summary
The present disclosure describes a semiconductor structure and a method for forming the same. The semiconductor structure can include a substrate, first and second fin structures formed over the substrate, and an isolation structure between the first and second fin structures. The isolation structure can include a lower portion and an upper portion. The lower portion of the isolation structure can include a metal-free dielectric material. The upper portion of the isolation structure can include a metallic element and silicon.