FinFET Dual Spacer Structure for Etching Resistance
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Solution Overview
Problem
Existing FinFET devices face challenges in achieving optimal performance due to limitations in fabrication processes, particularly in the etching resistance of low-k dielectric materials used for gate spacer layers, which affect device speed and reliability.
Innovation Solution
The introduction of additional spacer layers with higher etching resistance, made of materials like SiC, SiCN, or AlO, adjacent to the gate spacer layers, to protect underlying layers during etching processes and prevent electrical shorts, while allowing the use of low-k dielectric materials for increased device speed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If low-k dielectric materials are used for gate spacer layers to increase device speed, then device speed is improved, but etching resistance deteriorates
Solution Approach 1:
The patent uses composite material structures by combining low-k dielectric materials with higher etching resistance materials (such as silicon nitride, silicon oxynitride, or tantalum oxide) in a multi-layer gate spacer configuration. The low-k layer provides high device speed while the higher resistance layer protects against etching damage, resolving the contradiction between speed and etching resistance.
Solution Approach 2:
The gate spacer structure is segmented into multiple layers with different material compositions and etching resistance properties. The low-k dielectric layer is separated from the etching process by introducing intermediate layers with higher etching resistance, allowing each layer to perform its specific function without compromising the other.
2Reliability
If additional spacer layers with higher etching resistance are added to protect underlying layers, then etching resistance is improved, but device complexity increases
Solution Approach 1:
The higher etching resistance materials are applied locally only where needed for protection during etching processes, rather than throughout the entire gate spacer structure. This localized approach provides necessary protection while minimizing the increase in overall device complexity.
Solution Approach 2:
The patent employs composite material structures by combining low-k dielectric materials with higher etching resistance materials (such as silicon nitride, silicon oxynitride, or tantalum oxide) in a multi-layer gate spacer configuration. The low-k layer provides high device speed while the higher resistance layer protects against etching damage, resolving the contradiction between speed and etching resistance.
3Reliability
If multiple spacer layers are used to prevent electrical shorts, then reliability is improved, but fabrication time increases
Solution Approach 1:
The additional spacer layers with higher etching resistance are formed in advance before the etching processes that could cause electrical shorts. This preliminary protective action prevents potential damage before it occurs, ensuring reliability without requiring additional corrective steps later in the fabrication process.
Solution Approach 2:
The patent employs composite material structures by combining low-k dielectric materials with higher etching resistance materials (such as silicon nitride, silicon oxynitride, or tantalum oxide) in a multi-layer gate spacer configuration. The low-k layer provides high device speed while the higher resistance layer protects against etching damage, resolving the contradiction between speed and etching resistance.
Data Source
AI summary
A FinFET device structure is provided. The FinFET device structure includes a first gate structure formed over a fin structure and a first spacer layer formed on the first gate structure. The FinFET device structure includes a first insulation layer formed over the fin structure, and the first insulating layer is adjacent to and separated from the first spacer layer. The FinFET device structure includes a conductive plug formed over the first gate structure, and the conductive plug is formed over the first spacer layer and the first insulation layer.