IJPEM
Microstructural Interface Analysis and Multilayer Damage Mechanism in Laser-Sliced 4H-SiC Wafers
Qiu Chen, Xiufang Chen, Rongkun Wang/Shandong University
- Keywords : 4H-SiC, Laser slicing, Multilayer interface, Grinding
- With the increasing demand for high-quality 4H-SiC wafers, laser slicing has emerged as a promising technique owing to its high efficiency and minimal material loss. However, it induces a multilayer interfacial structure—comprising a stepped, transitional, and intrinsic SiC layer—whose distinct grinding responses accelerate wheel wear and cost. To address this, we quantitatively characterized the interface at depths of 0–20, 20–40, and 40–60 μm using 3D topography, Raman spectroscopy, stress mapping, and geometry analysis. The step height decreased from 31.76 μm to 0.28 μm, and residual stress declined to 5.01 MPa, while microcracks and laser traces vanished, restoring crystal integrity. The wafer geometry stabilized, with warp and bow reduced to approximately 35 μm and 24 μm, respectively. Combining beam spot simulations with observed surface topography revealed a distinct nonlinear pattern of wheel wear, with a peak occurring in the transition layer. This behavior was attributed to pronounced stress gradients and defect accumulation, which facilitated brittle chipping and secondary abrasion, further exacerbated by localized heat generation. Based on these findings, an interface-guided grinding strategy was proposed, using a segmented feed rate of 0.8–0.8–0.4 μm/s and a 10–20 s spark-out, reducing total grinding time by 25.2%, wheel wear by 23.9%, and maintaining surface integrity (Sa ≈ 13 nm). This framework offers a scalable, low-cost route for high-precision 4H-SiC wafer manufacturing.
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