SiC Wafer Side Modified Lines for Crack-Stable Stealth Dicing
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Solution Overview
Problem
The formation of multiple modified lines on the entire side surfaces of SiC semiconductor layers can lead to fluctuations in electrical characteristics and the generation of cracks, making it undesirable.
Innovation Solution
A SiC semiconductor device with a single modified line per side surface, extending in a band shape along the tangential direction, is formed to reduce the influence on the SiC semiconductor layer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If multiple modified lines are formed over the entire side surfaces of the SiC semiconductor layer, then the stealth dicing method can be effectively applied to cut the high-hardness SiC wafer, but electrical characteristics fluctuate and cracks may generate
Solution Approach 1:
The patent segments the modified lines from covering the entire side surface to being confined only to the peripheral regions adjacent to the main surfaces. This segmentation reduces the total area of modified regions while maintaining the dicing effectiveness at the cut edges, thereby resolving the contradiction between dicing efficiency and electrical stability.
Solution Approach 2:
The patent applies local quality by creating modified regions only where needed (at the periphery near main surfaces) rather than uniformly across the entire side surface. The modified lines are localized to specific peripheral zones, allowing the central active regions to maintain their original electrical characteristics while still enabling effective stealth dicing at the edges.
2Ease of manufacture
If multiple modified lines are formed over the entire side surfaces of the SiC semiconductor layer, then the SiC wafer can be cut without a dicing blade, but cracks may generate starting from the modified lines
Solution Approach 1:
By segmenting the modified lines to exist only in peripheral regions rather than covering the entire side surface, the patent reduces the number of modified lines that could serve as crack initiation points. This segmentation maintains the ease of manufacture through stealth dicing while minimizing crack risk.
Solution Approach 2:
The patent applies partial action by forming modified lines only in the necessary peripheral regions rather than excessively covering the entire side surface. This partial modification is sufficient to enable stealth dicing while avoiding the excessive modification that would create more potential crack sources.
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 approach minimizes the adverse effects on the SiC semiconductor layer by reducing electrical fluctuations and crack generation, enhancing the device's stability and performance.
Implementation Method 1
after laser light is selectively irradiated onto the SiC semiconductor wafer, the SiC semiconductor wafer is cut along the portion irradiated with the laser light
Data Source
AI summary
An SiC semiconductor device includes an SiC semiconductor layer including an SiC monocrystal and having a first main surface as an element forming surface, a second main surface at a side opposite to the first main surface, and a plurality of side surfaces connecting the first main surface and the second main surface, and a plurality of modified lines formed one layer each at the respective side surfaces of the SiC semiconductor layer and each extending in a band shape along a tangential direction to the first main surface of the SiC semiconductor layer and modified to be of a property differing from the SiC monocrystal.