Silicon carbide (SiC) is not only a critical technology for national defense security but also a key material driving advancements in the global automotive and energy industries. In the processing chain of SiC single crystals, slicing the grown ingot into wafers is the very first step, and the performance of this slicing stage determines the efficiency and quality of subsequent thinning and polishing processes. However, wafer slicing often induces surface and subsurface cracks, which significantly increase wafer breakage rates and overall manufacturing costs. Therefore, controlling surface crack damage during slicing is of great importance for the advancement of SiC device manufacturing.
At present, SiC ingot slicing faces two major challenges:
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High material loss in traditional multi-wire sawing
SiC is an extremely hard and brittle material, which makes cutting and polishing highly challenging. Conventional multi-wire sawing often leads to severe bowing, warping, and cracking during processing, resulting in substantial material loss. According to Infineon’s data, under the traditional reciprocating fixed-abrasive diamond wire sawing method, the material utilization rate during slicing is only about 50%. After subsequent grinding and polishing, the cumulative loss can reach as high as 75% (around 250 µm per wafer), leaving a very limited usable portion.
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Long processing cycle and low throughput
International production data shows that with 24-hour continuous operation, producing 10,000 wafers can take approximately 273 days. To meet market demand, large quantities of wire-saw equipment and consumables are required. Moreover, multi-wire sawing introduces high surface/interface roughness and causes serious contamination issues such as dust and wastewater.
To address these critical challenges, Professor Xiangqian Xiu’s research team at Nanjing University has developed large-scale SiC laser slicing equipment. This innovative technology adopts laser slicing instead of wire sawing, significantly reducing material loss and boosting production efficiency. For example, using a single 20 mm SiC ingot, the number of wafers produced by laser slicing is more than double that of conventional wire-sawing. Additionally, wafers sliced by laser demonstrate superior geometric properties, with single-wafer thickness reduced to as low as 200 µm, further increasing wafer output.
Competitive Advantages
The project has successfully completed the development of a large-size prototype laser slicing system, achieving slicing and thinning of 4–6 inch semi-insulating SiC wafers, as well as 6-inch conductive SiC ingots. Validation for 8-inch SiC ingot slicing is currently underway. The equipment offers multiple advantages, including shorter slicing times, higher annual wafer output, and lower per-wafer material loss, with an overall production yield improvement exceeding 50%.
Market Prospects
Large-scale SiC laser slicing equipment is expected to become the core tool for future 8-inch SiC ingot processing. Currently, such equipment relies heavily on imports from Japan, which are not only expensive but also subject to export restrictions. The domestic demand for SiC laser slicing and thinning equipment exceeds 1,000 units, yet no mature domestic solutions are commercially available. Therefore, the large-scale SiC laser slicing equipment developed by Nanjing University holds tremendous market potential and economic value.
Beyond SiC applications, this laser slicing system can also be applied to other advanced materials such as gallium nitride (GaN), gallium oxide (Ga₂O₃), and diamond, broadening its industrial application prospects.
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