Unlined Sealed Trenches in Superjunction Devices
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Solution Overview
Problem
In semiconductor manufacturing, filling trenches with dielectric material can lead to thermal stress due to material property differences, making the process costly and complicated, and incorporating mobile ions can result in unstable high-voltage breakdown characteristics.
Innovation Solution
The use of unlined and sealed trenches in semiconductor devices, where the trenches are capped with a sealing material like spun-on glass, eliminating the need for filling with dielectric material and reducing thermal stress by maintaining a consistent material environment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If trenches are filled with dielectric material, then isolation between regions is achieved, but thermal stress occurs due to divergent thermal properties between the dielectric material and substrate
Solution Approach 1:
The patent removes the dielectric filling material from the trench, leaving it empty and sealed. This extraction eliminates the source of thermal stress while maintaining isolation through the sealed structure and air buffer, directly resolving the contradiction between achieving isolation and avoiding thermal stress.
Solution Approach 2:
The patent fills the trench with air (an inert atmosphere) rather than dielectric material. This creates an electrically insulating environment that provides isolation while having minimal thermal impact compared to solid dielectric materials, thus reducing thermal stress while maintaining isolation functionality.
2Reliability
If trenches are filled with dielectric material, then isolation is achieved, but the manufacturing process becomes costly and complicated
Solution Approach 1:
The patent eliminates the trench filling step entirely by removing the dielectric material requirement. The isolation function is achieved through the sealed trench structure itself, which simplifies the manufacturing process by removing complex filling, planarization, and integration steps while maintaining effective isolation.
Solution Approach 2:
Instead of filling the trench to achieve isolation, the patent inverts the approach by leaving the trench empty and using the sealed structure with air buffer to provide isolation. This inversion eliminates the need for complex dielectric filling processes while achieving the same or better isolation效果.
Data Source
AI summary
A semiconductor device includes unlined and sealed trenches and methods for forming the unlined and sealed trenches. More particularly, a superjunction semiconductor device includes unlined, and sealed trenches. The trench has sidewalls formed of the semiconductor material. The trench is sealed with a sealing material such that the trench is air-tight. First and second regions are separated by the trench. The first region may include a superjunction Schottky diode or MOSFET. In an alternative embodiment, a plurality of regions are separated by a plurality of unlined and sealed trenches.