FinFET Gate Spacer Structure for Etch-Resistant Low-k Sealing
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Solution Overview
Problem
The semiconductor industry faces challenges in reducing damage during the manufacturing of FinFETs while maintaining a suitable dielectric constant, which affects the integration density and performance of electronic components.
Innovation Solution
The use of seal spacers, specifically a multi-layer spacer structure with a carbon-rich outer shell and an oxygen-rich bulk dielectric material, is implemented to enhance etch resistance and reduce dielectric constant, thereby minimizing damage and improving device performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If conventional single-layer spacer structures are used, then the manufacturing process is simpler, but etch resistance is insufficient causing damage to underlying layers
Solution Approach 1:
The spacer structure is divided into multiple layers with distinct functions: a first spacer layer providing etch resistance, a second spacer layer providing dielectric properties, and an optional third spacer layer. This segmentation allows each layer to be optimized for its specific function, resolving the contradiction between etch resistance and structural complexity.
Solution Approach 2:
The patent uses composite spacer structures combining different materials (e.g., silicon nitride, silicon oxide, silicon oxynitride) with complementary properties. The composite structure achieves superior etch resistance and dielectric constant performance that cannot be obtained with single-layer structures, while the modular design keeps the manufacturing process manageable.
2Reliability
If high dielectric constant materials are used to maintain performance, then device performance is improved, but damage during etching processes increases
Solution Approach 1:
The dielectric function is separated from the etch resistance function by using different spacer layers. The second spacer layer provides the required dielectric constant for device performance, while the first spacer layer provides etch resistance to protect underlying structures, thus eliminating the trade-off between performance and damage.
Solution Approach 2:
The first spacer layer acts as an intermediary protective layer that shields the high dielectric constant second spacer layer and underlying sensitive structures from etching damage. This mediator allows the use of high-performance dielectric materials without suffering from their etching vulnerabilities.
3Productivity
If thinner spacer layers are used to increase integration density, then more components fit in given area, but etch resistance and protection capability are reduced
Solution Approach 1:
The composite multi-layer spacer structure achieves high etch resistance and protection capability in a compact form factor. By combining thin layers of different materials with complementary properties, the structure provides sufficient protection and dielectric performance while maintaining thin overall dimensions to support high integration density.
Data Source
AI summary
Semiconductor devices and methods of manufacture are presented in which spacers are manufactured on sidewalls of gates for semiconductor devices. In embodiments the spacers comprise a first seal, a second seal, and a contact etch stop layer, in which the first seal comprises a first shell along with a first bulk material, the second seal comprises a second shell along with a second bulk material, and the contact etch stop layer comprises a third bulk material and a second dielectric material.