Single-Active-Area ESD Layout With Deep Trench Isolation
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Solution Overview
Problem
Existing semiconductor devices with multiple-active-area (MAA) ESD protection devices have large die area and manufacturing costs due to significant separation distance between emitter and collector regions, leading to low gain and complexity in interconnect design, making them inefficient for low-voltage operations.
Innovation Solution
Implementing a single-active-area (SAA) ESD protection device with deep trench isolation structures and epitaxially grown semiconductor material, allowing for reduced separation distance and increased flexibility in layout, similar to logic transistors, thereby reducing die area and manufacturing costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple-active-area (MAA) ESD protection devices are used with significant separation distance between emitter and collector regions, then ESD protection functionality is achieved, but die area increases and manufacturing costs increase
Solution Approach 1:
The patent merges the emitter and collector regions into a single active area, eliminating the need for separate active areas and the shallow trench isolation structure between them. This consolidation reduces the overall die area while maintaining ESD protection functionality through the use of deep trench isolation structures that extend deeper into the substrate.
Solution Approach 2:
The patent transitions from a planar separation approach (shallow trench isolation in the horizontal plane) to a vertical separation approach (deep trench isolation extending downward into the substrate). This dimensional change allows the emitter and collector to be closer horizontally while maintaining electrical isolation through the deeper vertical structure.
2Reliability
If multiple-active-area (MAA) ESD protection devices are used with significant separation distance between emitter and collector regions, then ESD protection functionality is achieved, but manufacturing costs increase
Solution Approach 1:
The patent consolidates the ESD protection device structure by merging emitter and collector into one active area, reducing the number of isolation structures and interconnect layers required. This simplification directly reduces manufacturing steps and associated costs while preserving ESD protection functionality.
Solution Approach 2:
The single active area structure allows the ESD protection device to share process steps and materials with standard logic transistors, enabling universal manufacturing processes. The deep trench isolation structure serves multiple functions: electrical isolation, mechanical support, and process integration with standard CMOS fabrication.
3Reliability
If multiple-active-area (MAA) ESD protection devices are used with significant separation distance between emitter and collector regions, then ESD protection functionality is achieved, but gain decreases and low-voltage operation becomes problematic
Solution Approach 1:
The patent moves the isolation mechanism from the horizontal dimension to the vertical dimension by using deep trench isolation structures that extend deeper into the substrate. This allows the emitter and collector to be positioned closer together horizontally, improving gain while maintaining electrical isolation through the deeper vertical structure.
Solution Approach 2:
The patent changes the key parameter of isolation depth rather than isolation distance. By increasing the depth of the trench isolation structure while reducing the horizontal separation distance between emitter and collector, the device achieves both electrical isolation and improved gain characteristics for low-voltage operation.
4Reliability
If multiple-active-area (MAA) ESD protection devices are used with significant separation distance between emitter and collector regions, then ESD protection functionality is achieved, but interconnect structure design complexity increases
Solution Approach 1:
The patent merges the emitter and collector into a single active area, which simplifies the interconnect structure by eliminating the need for complex routing around deep shallow trench isolation structures. The reduced separation distance allows for more direct and simpler interconnect paths between device terminals.
Data Source
AI summary
A semiconductor device includes a P-doped well having a first concentration of P-type dopants in the substrate; a P-doped region having a second concentration of P-type dopants in the substrate and extending around a perimeter of the P-doped well; a shallow trench isolation structure (STI) between the P-doped well and the P-doped region; an active area on the substrate, the active area including an emitter region and a collector region; a deep trench isolation structure (DTI) extending through the active area and between the emitter region and the collector region; and an electrical connection between the emitter region and the P-doped region.