Semiconductor device and method of manufacture
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Solution Overview
Problem
During the manufacturing of nano-FET devices, intermediate structures are prone to interface intermixing due to thermal processes, leading to mobility degradation, which is not effectively addressed by existing technologies.
Innovation Solution
Replacing layers of nanosheets with materials less susceptible to intermixing, such as using a contour-flowable chemical vapor deposition (c-FCVD) process to form an interposer material that coats and fills gaps between nanosheets, reducing the risk of intermixing and enhancing the stability of nanostructures during thermal processing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If nanosheets are used to improve device performance, then mobility is enhanced, but interface intermixing occurs during thermal processes leading to mobility degradation
Solution Approach 1:
An interposer layer is introduced as an intermediary between adjacent nanosheets. This interposer material physically separates the nanosheet interfaces, preventing direct contact and intermixing during thermal processing. The interposer acts as a barrier that maintains interface integrity while allowing the nanosheets to retain their high-mobility characteristics.
Solution Approach 2:
The patent addresses the harmful effect of interface intermixing by using the interposer material to create controlled separation. The presence of the interposer, which initially might seem to add complexity, actually benefits the device by preventing degradation and ensuring long-term stability of the high-mobility nanosheet interfaces.
2Ease of manufacture
If thermal processes are applied to manufacture nano-FET devices, then device fabrication is enabled, but interface intermixing occurs leading to mobility degradation
Solution Approach 1:
The interposer layer is formed between nanosheets before subsequent thermal processing steps. This preliminary placement of the interposer material ensures that when thermal processes are later applied for device fabrication, the interfaces are already protected from intermixing. The protective structure is in place before the harmful thermal exposure occurs.
Solution Approach 2:
The interposer material serves as a protective intermediary that allows thermal processing to proceed while preventing the harmful intermixing effect. It mediates between the necessary thermal fabrication processes and the need to preserve interface integrity, enabling both manufacturing feasibility and precision.
3Productivity
If minimum feature size is reduced to increase integration density, then more components are integrated into given area, but additional manufacturing problems arise
Solution Approach 1:
The patent applies segmentation by dividing the structure into nanosheets with intervening interposer layers. This segmentation approach allows for smaller effective feature sizes and higher integration density while the interposer materials provide natural separation that simplifies the manufacturing process by preventing intermixing at reduced dimensions.
Solution Approach 2:
The introduction of interposer materials changes the structural parameters of the device, adding a new material component and layer configuration. However, this parameter change simplifies manufacturing by providing built-in protection against intermixing, offsetting the increased structural complexity with process simplification.
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 mitigates the risk of nanosheet interface intermixing, improving the mobility and reliability of nano-FET devices by using a seam-free interposer material that fills gaps and supports subsequent processing without causing further degradation.
Implementation Method 1
using a contour-flowable chemical vapor deposition (c-FCVD) process to form an interposer material that coats and fills gaps between nanosheets
Data Source
AI summary
Semiconductor devices and methods of manufacture are discussed. In an embodiment, a method of manufacturing a semiconductor device includes: forming first nanostructures from a first material over a substrate; forming second nanostructures from a second material different from the first material over the substrate, wherein the first nanostructures and the second nanostructures alternate vertically above the substrate; removing the first nanostructures; after the removing the first nanostructures forming an interposer in between the second nanostructures; after the forming the interposer forming a first source/drain region over the substrate and in direct physical contact with the second nanostructures; and removing the interposer exposing surfaces of each of the second nanostructures.