SiC Wafer Manufacturing Process

1.Wire Cutting Station The silicon carbide wafer is first positionally corrected in crystal orientation before processing. Multiple wire cutting machines, paired with diamond slurry of appropriate viscosity, are used for crystal cutting to minimize surface lines and reduce post-cut warpage.

2.Chamfering Station Using grinding wheels of different coarseness, the micro-angled edges generated after wire cutting are sequentially removed to prevent chipping and cracking during subsequent surface processing.

3.Grinding Station Different numbered diamond disc wheels are sequentially used to grind the surface of the wafer. This process not only removes the wire-cutting marks but also evens out the wafer's thickness variation (TTV).

4.Polishing Station Utilizing chemical mechanical polishing (CMP) with suitable polishing pads and slurries under acidic conditions, this station performs polishing on the wafers after grinding. The primary goal is to eliminate surface damage layers and control the wafer's surface roughness to less than 0.1nm (Ra).

5.Post-Polishing Cleaning Station A multi-slot cleaning tank is employed, and a sequence of different cleaning solutions and deionized water is used to remove residual polishing slurry from the wafers. This prevents the formation of residues and stains on the wafer's surface during subsequent processing.

6.Flatness Measurement Station Wafers subjected to the flattening process are automatically measured for surface characteristics using a dual-beam non-contact method. This includes local flatness, curvature, and warpage, serving as a quality check for the wafers.

7.Final Cleaning Station Wafers meeting specifications undergo continuous cleaning using automated multi-slot cleaning equipment with SC1 and SC2 solutions combined with high-purity deionized water (18DI). This process not only removes surface metal contamination (< 5E9) and tiny particles but also prepares for subsequent surface defect measurements.

8.Surface Defect Measurement Station This station utilizes a dual-wavelength laser inspection device (Candela) operating in both UV and visible light. It quantifies tiny scratches and various-sized surface particles on the wafer surface. Additionally, the UV laser scans and contrasts the native crystal defects on the wafer, such as micro-pipe defects (MP), basal plane defects (BPD), and carbon cluster defects.