Insulating Fin Structure for Source/Drain Separation and CMP Control
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Solution Overview
Problem
As semiconductor devices continue to shrink in feature size, issues such as undesired merging of source/drain regions and extrusion defects on insulating fins arise, requiring improved methods for film quality control and chemical mechanical polish (CMP) rate management.
Innovation Solution
The use of insulating fins with alternating high-k dielectric layers and capping layers is implemented to reduce extrusion defects and enhance film quality, with these layers being formed between stacks of nanostructures to prevent coalescing of epitaxial source/drain regions and improve CMP control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If feature size is reduced to improve integration density, then more components can be integrated into a given area, but undesired merging of source/drain regions occurs
Solution Approach 1:
The patent introduces insulating fins that segment and separate adjacent source/drain regions, preventing their merging as feature sizes are reduced. These fins act as physical barriers between neighboring device regions, enabling continued scaling while maintaining region separation.
Solution Approach 2:
The insulating fins serve as intermediary structures between source/drain regions, providing isolation and preventing direct contact or merging. This intermediary element allows closer spacing of components while maintaining proper electrical isolation.
2Productivity
If feature size is reduced to improve integration density, then more components can be integrated into a given area, but extrusion defects on insulating fins arise
Solution Approach 1:
The patent employs alternating high-k dielectric layers and capping layers to form a composite structure on the insulating fins. This multi-layer composite approach improves film quality and reduces extrusion defects by combining materials with complementary properties that resist defect formation during CMP processes.
Solution Approach 2:
The patent modifies the physical and chemical parameters of the insulating fin structure by introducing alternating layers with different material properties. This changes the mechanical and chemical characteristics of the fin surface, making it more resistant to extrusion defects during subsequent processing steps.
3Ease of manufacture
If conventional insulating fins are used, then device fabrication is simplified, but CMP rate control deteriorates
Solution Approach 1:
The alternating high-k dielectric and capping layers create a composite structure with tailored CMP properties. Different layers etch at different rates, providing superior control over the CMP process while maintaining the overall insulating function and structural integrity of the fins.
Data Source
AI summary
A semiconductor device includes a first channel region, a second channel region, and a first insulating fin, the first insulating fin being interposed between the first channel region and the second channel region. The first insulating fin includes a lower portion and an upper portion. The lower portion includes a fill material. The upper portion includes a first dielectric layer on the lower portion, the first dielectric layer being a first dielectric material, a first capping layer on the first dielectric layer, the first capping layer being a second dielectric material, the second dielectric material being different than the first dielectric material, and a second dielectric layer on the first capping layer, the second dielectric layer being the first dielectric material.