Silicon-Plug Trench Segmentation for Crossing Voltage Isolation
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Solution Overview
Problem
Conventional deep trench isolation in SOI and SOI-like technologies restricts the separation of different voltage domains and prevents deep trench isolation crossings, leading to electrical connections and failure, and limits the use of asymmetrical and high-voltage devices due to the risk of short circuits and increased device area.
Innovation Solution
The implementation of silicon plugs surrounded by dielectric material within trenches allows for deep trench isolation crossings and segmentation of conductive fill, enabling separation of voltage domains without additional high-voltage routing and providing enhanced insulation, allowing for asymmetrical and high-voltage device configurations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional deep trench isolation rings are used to separate different voltage domains, then electrical isolation is achieved, but device area increases and asymmetrical/high-voltage device configurations are limited
Solution Approach 1:
The continuous conductive fill material in the deep trench isolation is segmented into multiple isolated sections by inserting silicon plugs at strategic locations. This segmentation allows the trench isolation structure to be discontinuous in the conductive path while maintaining physical continuity of the trench, thereby reducing the area required for voltage domain separation without compromising electrical isolation reliability.
Solution Approach 2:
Silicon plugs are introduced as intermediary elements within the deep trench isolation structure. These plugs serve dual functions: they provide mechanical support and enable precise control over the conductive fill continuity. By positioning these intermediary silicon plugs at specific locations, the patent achieves compact voltage domain separation while maintaining reliable electrical isolation through the segmented conductive paths.
2Adaptability or versatility
If deep trench isolation crossings are permitted, then device layout flexibility improves, but electrical connection (short) risk increases
Solution Approach 1:
At trench intersection points, silicon plugs are strategically positioned to segment the conductive fill material into isolated sections. This segmentation ensures that even when trenches cross or intersect, the conductive paths remain electrically isolated, preventing short circuits while allowing flexible device layouts with multiple trench intersections and asymmetrical configurations.
Solution Approach 2:
The conductive fill material exhibits different electrical properties at different locations within the trench structure. By introducing silicon plugs at specific local positions (particularly at intersections and near device regions), the patent creates localized variations in conductive path continuity. This local quality control allows trench crossings for layout flexibility while maintaining electrical isolation reliability through position-dependent conductive fill segmentation.
3Ease of manufacture
If conventional deep trench isolation is used, then manufacturing process is simple, but critical dimension requirements increase and insulation capabilities are limited
Solution Approach 1:
The conductive fill is segmented by silicon plugs, which allows the use of slightly larger critical dimensions for the trench structure while achieving the same level of electrical isolation. The segmented conductive paths reduce the required clearance between adjacent conductive regions, thereby relaxing critical dimension requirements and enabling tighter spacing without compromising insulation capabilities.
Solution Approach 2:
Silicon plugs serve as intermediary structures that enhance the insulation capability of the deep trench isolation system. By introducing these plugs, the patent achieves superior electrical isolation with relaxed critical dimension constraints, as the plugs provide additional insulation barriers within the trench structure. This intermediary approach maintains manufacturing simplicity while improving insulation performance and reducing precision requirements.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This solution enables effective isolation of different voltage domains within the same silicon layer, reduces critical dimension requirements, and enhances insulation capabilities, preventing dielectric breakdown while enabling multi-channel capacitive coupling and efficient edge termination for high-voltage devices.
Implementation Method 1
a dielectric material separating the electrically conductive material from silicon material of the silicon layer
Implementation Method 2
a plurality of silicon plugs laterally surrounded by the dielectric material and dividing the electrically conductive material into a plurality of separate segments
Data Source
AI summary
A semiconductor device includes: a silicon layer having a frontside and an electrically insulated backside; a first trench extending through the silicon layer from the frontside to the electrically insulated backside and laterally isolating a first region of the silicon layer; an electrically conductive material in the first trench; a dielectric material separating the electrically conductive material from silicon material of the silicon layer; and a plurality of silicon plugs laterally surrounded by the dielectric material and dividing the electrically conductive material into a plurality of separate segments in the first trench. Additional embodiments of semiconductor devices and methods for manufacturing the semiconductor devices are also described.