SiC Power Semiconductor Corner Layout for Polyimide Crack Resistance
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Solution Overview
Problem
The polyimide film used in power semiconductor devices is prone to stress-induced breakage due to thermal cycling, leading to a loss of breakdown voltage integrity, which existing technologies fail to adequately address.
Innovation Solution
A power semiconductor device design featuring a termination region with a corner where the outer edge of the interlayer insulating film has a radius of curvature R1 and the inner edge of the insulating protective film has a radius of curvature R2, greater than R1, enhancing the film's resistance to stress and reducing the likelihood of crack formation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the insulating protective film is formed with a small radius of curvature at the inner edge, then the film can be formed more easily, but the film is more prone to stress-induced breakage and crack formation
Solution Approach 1:
The patent applies curvature principle by forming the inner edge of the insulating protective film with a radius of curvature R2 that is greater than the radius of curvature R1 of the interlayer insulating film outer edge. This curvature design prevents stress concentration at sharp corners, thereby suppressing crack initiation and propagation while maintaining manufacturability through controlled film formation processes
2Reliability
If the radius of curvature R2 of the inner edge of the insulating protective film is increased, then resistance to stress and crack formation is improved, but the manufacturing precision requirements increase
Solution Approach 1:
The patent employs parameter change principle by establishing a specific relationship between two geometric parameters: R2 (inner edge radius of insulating protective film) > R1 (outer edge radius of interlayer insulating film). This parameter relationship optimizes stress distribution while maintaining practical manufacturing precision through standard photolithography and film formation processes
3Ease of manufacture
If the insulating protective film is subjected to thermal stress from sealing members during thermal cycling, then the device can be sealed, but the film is more likely to break and lose breakdown voltage integrity
Solution Approach 1:
The patent applies preliminary anti-action principle by pre-designing the inner edge of the insulating protective film with a larger radius of curvature R2 before thermal cycling occurs. This pre-designed geometric feature creates stress relief that counteracts the thermal stress from sealing members during subsequent thermal cycling, preventing breakage and maintaining breakdown voltage integrity
Data Source
AI summary
A power semiconductor device includes a termination region having a corner and an element region inside the termination region. An SiC substrate spans the element region and the termination region. An interlayer insulating film has an outer edge in the termination region. A source electrode is in contact with the SiC substrate in the element region, and has an outer edge on the interlayer insulating film in the termination region. An insulating protective film covers the outer edge of the interlayer insulating film and the outer edge of the source electrode, and has an inner edge on the source electrode. At the corner of the termination region, the outer edge of the interlayer insulating film has a radius of curvature R1, and the inner edge of the insulating protective film has a radius of curvature R2. The radius of curvature R2 is greater than the radius of curvature R1.