Semiconductor Isolation Layer Trench Buffering for HEIP and Process Margin
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Solution Overview
Problem
Conventional semiconductor device fabrication technologies face challenges in securing an isolation layer formation process margin in regions with high unit component density while preventing degradation of the hot electron induced punchthrough (HEIP) effect in regions with low unit component density.
Innovation Solution
The solution involves forming an interface layer of varying thickness in different regions, with a buffer layer at the bottom corner of the trench and a liner layer over the interface layer, and a gap-fill layer that fills the trench, allowing for secure process margins and preventing HEIP degradation by relieving electric field concentration and improving deposition characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the thickness of the interface layer is reduced in the first region to secure process margin, then the process margin is improved, but the HEIP effect is degraded in the second region
Solution Approach 1:
The patent applies local quality by forming a first interface layer with a first thickness in the first region and a second interface layer with a second thickness in the second region, where the first thickness is less than the second thickness. This allows each region to have optimized interface layer thickness tailored to its specific requirements: thinner in high-density regions for process margin and thicker in low-density regions for HEIP effect prevention.
Solution Approach 2:
The patent segments the interface layer formation process by treating the first and second regions separately. Instead of forming a uniform interface layer across the entire substrate, the process is divided into region-specific steps: forming the first interface layer in the first region, then forming the second interface layer in the second region, allowing independent thickness control for each region.
2Productivity
If the critical dimension of the trench is reduced to increase integration degree, then the productivity is improved, but the process margin is reduced
Solution Approach 1:
The patent changes the thickness parameter of the interface layer to accommodate reduced trench critical dimensions. By reducing the interface layer thickness in the first region where trenches have smaller critical dimensions, the patent maintains adequate process margin even as integration degree increases and trench dimensions are reduced.
3Ease of manufacture
If a uniform interface layer thickness is formed in both regions, then the ease of manufacture is improved, but the process margin is insufficient in the first region
Solution Approach 1:
The patent transitions from uniform interface layer formation to local quality-based formation, where the interface layer thickness is customized for each region. The first interface layer is formed with a first thickness in the first region and the second interface layer is formed with a second thickness in the second region, optimizing process margin for each region's specific requirements.
Data Source
AI summary
A semiconductor device with an isolation layer buried in a trench includes an interface layer formed on the surface of the trench, a buffer layer formed in the interface layer at a bottom corner of the trench, a liner layer formed over the interface layer, and a gap-fill layer gap-filling the trench over the liner layer. The trench includes a micro-trench formed at the bottom corner thereof, and the buffer layer fills the micro-trench.