FinFET Single Diffusion Break Structure for Metal Gate Integration
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Solution Overview
Problem
The integration of single diffusion break (SDB) structure and metal gate fabrication in FinFET fabrication remains challenging, hindering the advancement of three-dimensional transistor technology.
Innovation Solution
A method involving forming a fin-shaped structure, creating a first and second gate structure, transforming them into metal gates, and forming a hard mask, followed by removing parts to create a trench and filling it with a dielectric layer to form a single diffusion break (SDB) structure, with the SDB having a bottom and top portion of different widths.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If shallow trench isolation (STI) is formed around the fin-shaped structure and insulating material is deposited into the trench to form single diffusion break (SDB) structure, then the isolation and diffusion control are improved, but the integration with metal gate fabrication remains problematic and complex
Solution Approach 1:
The patent combines the SDB structure formation with the metal gate fabrication process by using the same trench formation steps. The trench is formed to expose the fin-shaped structure, and both the SDB insulating material and metal gate material are deposited and processed in an integrated sequence, eliminating separate processing steps and reducing overall fabrication complexity
Solution Approach 2:
The patent forms the trench structure and prepares the fin-shaped structure exposure before depositing the insulating material for SDB. This preliminary preparation of the trench geometry and fin exposure enables subsequent metal gate and SDB materials to be deposited in an integrated process sequence, simplifying the overall integration
2Reliability
If the three-dimensional structure of FinFET is used to increase overlapping area between gate and fin-shaped structure, then the channel region control is improved and current is increased, but the integration of SDB structure and metal gate fabrication remains challenging
Solution Approach 1:
The patent merges the SDB formation and metal gate fabrication into a single integrated process flow. The trench is formed to expose the fin, and subsequent deposition of insulating material followed by metal gate material occurs in sequence without intermediate steps, making the three-dimensional FinFET structure with SDB more manufacturable
Solution Approach 2:
The patent segments the fabrication process into distinct material deposition stages: first insulating material for SDB, then metal gate material. This segmentation within the integrated process allows precise control of each layer while maintaining overall process integration and simplicity
Data Source
AI summary
A semiconductor device includes a fin-shaped structure on a substrate, a gate structure on the fin-shaped structure and an interlayer dielectric (ILD) layer around the gate structure, and a single diffusion break (SDB) structure in the ILD layer and the fin-shaped structure. Preferably, the SDB structure includes a bottom portion and a top portion on the bottom portion, in which the top portion and the bottom portion include different widths.