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Silicon carbide (SiC) material, recognized as a third-generation semiconductor for manufacturing power semiconductor devices, possesses excellent physical and chemical properties such as high thermal conductivity, high breakdown field strength, wide bandgap, high electron saturation drift velocity, along with resistance to high temperatures and radiation, and good chemical stability. However, due to its extreme hardness (Mohs hardness of 9.2) and strong chemical stability, SiC presents significant challenges in both the grinding and polishing processes. To shorten the polishing time of the final step, namely chemical mechanical polishing (CMP), it is necessary to minimize the surface damage layer and reduce the roughness of the wafer.

Traditional mechanical grinding or polishing employs diamond slurry. Under appropriate pressure and with the high-speed rotation of a metal grinding disc or a pad attached to a polishing platen, the surface of the SiC wafer is ground or polished. However, this approach faces a dilemma: pursuing a high material removal rate leads to a larger damage layer and higher surface roughness, which is detrimental to subsequent CMP; conversely, achieving a low damage layer and low surface roughness requires multiple process steps and increased processing time.

To address the aforementioned technical challenges, this paper provides a rapid polishing technical solution for SiC wafers using diamond polishing paste, which comprises the following steps:

Mounting the SiC wafer onto the wax-free adsorption pad of a holding device;

Applying a layer of diamond polishing paste with a thickness of 0.1–0.5 mm onto the polishing pad; the particle size of the diamond polishing paste is 0.2–1.0 μm;

Placing the holding device onto the polishing equipment, setting the polishing pressure of the equipment to 25–255 g/cm², the platen rotation speed to 30–60 rpm, and the polishing head rotation speed to 10–55 rpm;

Performing the polishing operation on the SiC wafer by introducing a liquid onto the polishing platen at a flow rate of 1–20 ml/min, and reapplying the diamond polishing paste to a thickness of 0.1–0.5 mm at intervals of 20–60 minutes;

Cleaning and inspecting the SiC wafer upon completion of polishing.