Semiconductor Device Electrode Boundary Positioning
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Solution Overview
Problem
Semiconductor devices in power conversion units are prone to cracks in the active region due to thermal stress from power cycles and cold cycles, as the boundary between the connection electrode and the protective film is located over the active region, leading to potential damage.
Innovation Solution
The semiconductor device design includes a semiconductor substrate with an active region and an outer peripheral region, where the connection electrode's boundary with the protective film is positioned in the outer peripheral region, away from the active region, and a method for manufacturing involves forming a silicon oxide film, patterning it to create a contact hole, forming base and connection electrodes, and applying a protective film to cover the electrodes while exposing the connection electrode for soldering, ensuring the boundary is outside the active region.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the boundary between the connection electrode and the protective film is located over the active region, then the device structure is simplified and manufacturing is easier, but thermal stress concentrates on the active region causing cracks and reducing reliability
Solution Approach 1:
The connection electrode is designed with a stepped structure having different levels, where the first connection electrode portion is at a higher level than the second connection electrode portion. This vertical dimensionality change allows the boundary between the connection electrode and protective film to be positioned in the outer peripheral region rather than directly over the active region, dispersing thermal stress while maintaining structural integrity.
2Reliability
If the boundary between the connection electrode and the protective film is positioned in the outer peripheral region, then thermal stress is dispersed away from the active region, but the device structure becomes more complex
Solution Approach 1:
The connection electrode is segmented into multiple portions (first connection electrode portion and second connection electrode portion) at different levels. This segmentation allows the electrode to extend to the outer peripheral region while maintaining proper stress distribution, and the stepped structure can be formed through sequential deposition processes that are compatible with standard semiconductor manufacturing.
3Reliability
If the connection electrode extends to the outer peripheral region, then the boundary with the protective film is positioned away from the active region, but the electrode structure becomes more complex
Solution Approach 1:
The connection electrode employs a stepped configuration where different portions are at different vertical levels, creating a dynamic structure that adapts to the thermal stress distribution. The first connection electrode portion extends further laterally than the second portion, allowing the boundary to be positioned in the outer peripheral region while maintaining structural stability through the stepped design.
Data Source
AI summary
In a semiconductor device, a semiconductor element includes a semiconductor substrate, a surface electrode and a protective film. The semiconductor substrate has an active region and an outer peripheral region. The surface electrode includes a base electrode disposed on a front surface of the semiconductor substrate and a connection electrode disposed on the base electrode. The protective film covers a peripheral end portion of the base electrode and an outer peripheral edge of the connection electrode. The protective film has an opening to expose the connection electrode so as to enable a solder connection. A boundary between the outer peripheral edge of the connection electrode and the protective film is located at a position corresponding to the outer peripheral region in a plan view.