Merged Trench Isolation for Semiconductor Area Reduction
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Solution Overview
Problem
Existing semiconductor device fabrication techniques are area-consumptive and inefficient in isolating active devices, particularly when using dual deep-trench layouts, as they require separate wide and narrow deep trench regions that do not share trench portions, leading to increased space usage and potential electrical isolation issues.
Innovation Solution
Implementing a dual deep-trench layout configuration where wide deep trench regions are merged to share trench portions with narrow deep trench regions, reducing the inter-trench space and allowing for a more compact and efficient lateral isolation of semiconductor devices by forming concentric trench rings with varying depths and widths.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If separate wide and narrow deep trench regions are used for lateral isolation, then electrical isolation between devices is achieved, but area consumption increases and die component density decreases
Solution Approach 1:
The patent merges adjacent narrow deep trench regions that surround different active devices into a shared isolation structure. Instead of creating separate trench regions for each device, the narrow trenches are combined to form common isolation boundaries between multiple devices, thereby reducing redundant trench portions and minimizing area consumption while preserving electrical isolation functionality.
Solution Approach 2:
The shared narrow deep trench regions serve multiple functions simultaneously: they provide lateral isolation for multiple adjacent active devices, reduce overall area consumption, and maintain electrical isolation between tanked devices. This multi-functional design allows a single trench structure to fulfill isolation requirements for several devices rather than requiring separate dedicated trenches for each device.
2Reliability
If traditional dual deep-trench layout is used, then lateral isolation is provided, but inter-trench space increases and layout efficiency decreases
Solution Approach 1:
Adjacent narrow deep trench regions are merged into shared isolation structures that serve multiple devices. This consolidation eliminates redundant trench portions and reduces the inter-trench space between isolation regions, thereby improving layout efficiency and reducing the overall chip area required for the same level of device isolation.
3Reliability
If merged narrow deep trench regions are surrounded by wide deep trench regions, then electrical isolation is enhanced, but area consumption increases
Solution Approach 1:
The isolation structure is segmented into two distinct functional zones: inner narrow deep trench regions that provide primary lateral isolation between devices, and outer wide deep trench regions that provide enhanced electrical isolation and voltage management. This segmentation allows each zone to perform its specific function optimally while minimizing redundant materials and area consumption.
Solution Approach 2:
Different trench regions are designed with different widths and depths according to their specific isolation requirements. The narrow trenches are sufficient for basic lateral isolation between adjacent devices, while the wide trenches provide enhanced isolation where higher voltage management is needed. This local optimization ensures that area is not wasted on over-engineered isolation structures in all regions.
Data Source
AI summary
Active semiconductor devices in an integrated circuit are provided lateral electrical isolation by surrounding narrow deep trench isolation regions that are merged at shared portions of the narrow deep trench isolation regions. A wide deep trench isolation region laterally surrounds the merged narrow deep trench isolation regions.