Mesa-Adjacent Electrode Layout to Reduce Wafer Warpage
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Solution Overview
Problem
Vertical power devices with trench-gate structures experience warpage due to the tensile stress of the first electrode, which affects wafer conveyance and processing during singulation.
Innovation Solution
The first electrode is designed with strategically placed openings and recesses to reduce its volume, thereby reducing tensile stress and warpage, while maintaining electrical connectivity through connection portions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the first electrode is made with large volume to ensure electrical connectivity, then electrical conductivity is improved, but tensile stress and warpage increase
Solution Approach 1:
The first electrode is segmented into multiple isolated electrode regions separated by openings, rather than forming a continuous large-volume electrode. This segmentation reduces the overall volume and tensile stress while maintaining electrical connectivity through multiple distributed connection points between the electrode regions and the semiconductor layer
Solution Approach 2:
The electrode structure transitions from uniform volume distribution to non-uniform distribution with localized electrode regions. The openings are strategically positioned to reduce stress in critical areas while maintaining electrical connectivity where needed, creating local variations in electrode presence that optimize both mechanical and electrical performance
2Shape
If the first electrode volume is reduced to minimize warpage, then wafer warpage is improved, but electrical connectivity may be compromised
Solution Approach 1:
By dividing the electrode into multiple discrete regions connected to the semiconductor layer through separate connection structures, the design maintains adequate electrical connectivity while reducing the total electrode volume that generates tensile stress and causes warpage
Solution Approach 2:
The openings act as intermediary spaces that interrupt the continuous electrode structure, allowing reduction of electrode volume and stress while the connection portions serve as mediator structures that maintain electrical pathways between the electrode regions and the semiconductor layer
Data Source
AI summary
According to one embodiment, a semiconductor device has first and second electrodes with a semiconductor layer therebetween. An insulating layer is between the first electrode and the semiconductor layer. A gate electrode is adjacent to a mesa part of the semiconductor layer. A conductive member is also adjacent to the mesa part. A first connector is between the first electrode and the mesa part at a first position. A second connector is between the first electrode and the first conductive member at a second position. The first electrode has a first recess above the first conductive member at the first position. The first position and the second position are offset from each other in a length direction.