SiC MOSFET Dicing Structure to Block Crack Propagation
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Solution Overview
Problem
The manufacturing of silicon carbide (SiC) MOSFETs faces challenges due to the risk of cracking during the dicing process, which can lead to moisture and mobile ion ingress, causing degradation or short circuit failures, thereby reducing the reliability of the devices.
Innovation Solution
The semiconductor device design includes a dicing region with a silicon carbide layer where the maximum distance from the device region's surface is greater than that of the dicing region, creating a step that prevents crack propagation and uses a protective insulating layer to further prevent moisture and ion entry, along with an epitaxial growth method for specific layers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the wafer is cut along the dicing region, then the MOSFETs can be separated for packaging and use, but the device region may be cracked which reduces reliability
Solution Approach 1:
The invention divides the wafer into distinct device regions and dicing regions, with the dicing region serving as a sacrificial separation zone that is intentionally designed to be cut while protecting the device region. This segmentation allows efficient separation of MOSFETs while isolating cracks to non-critical areas.
Solution Approach 2:
The dicing region acts as an intermediary buffer zone between adjacent device regions. When cutting occurs, this intermediate region absorbs the mechanical stress and crack propagation, preventing direct transmission of damage to the critical device regions containing the MOSFETs.
2Ease of manufacture
If the wafer is cut along the dicing region, then individual devices can be obtained, but moisture and mobile ions may enter through cracks causing degradation
Solution Approach 1:
The device region is prepared in advance with protective structures and encapsulation layers before the dicing process. This preliminary protection ensures that even if cracks occur during cutting, moisture and mobile ions cannot penetrate into the critical device areas, preventing subsequent degradation.
Solution Approach 2:
The structure includes pre-designed protective layers and sealing mechanisms that cushion against the harmful effects of potential cracks. These protective elements are built in beforehand to block moisture and ion pathways that would otherwise exist if cracks reached the device region.
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 design enhances the reliability of SiC MOSFETs by preventing crack extension from the dicing region to the device region, reducing moisture and ion ingress, and maintaining device characteristics, thus improving overall device performance.
Implementation Method 1
a first maximum distance from the second face to the first face of the device region in a normal direction of the second face is greater than a second maximum distance from the second face to the first face of the dicing region in the normal direction
Implementation Method 2
there is a possibility that moisture and mobile ions may enter the device region through a crack
Implementation Method 3
an epitaxial growth method for specific layers
Data Source
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AI summary
A semiconductor device according to embodiments includes a device region and a dicing region surrounding the device region. The device region includes a first electrode, a second electrode, and a silicon carbide layer having a first face on the side of the first electrode and a second face on the side of the second electrode. At least a portion of the silicon carbide layer is provided between the first electrode and the second electrode. The dicing region includes the silicon carbide layer having the first face and the second face. A first maximum distance from the second face to the first face of the device region in a normal direction of the second face is greater than a second maximum distance from the second face to the first face of the dicing region in the normal direction.