Silicon carbide wafer is made of high purity silicon powder and high purity carbon powder as raw materials, and silicon carbide crystal is grown by physical vapor transfer method (PVT), and processed into silicon carbide wafer.
① Raw material synthesis. High purity silicon powder and high purity carbon powder were mixed according to a certain ratio, and silicon carbide particles were synthesized at high temperature above 2,000℃. After crushing, cleaning and other processes, the high purity silicon carbide powder raw materials which meet the requirements of crystal growth are prepared.
② Crystal growth. Using high purity SIC powder as raw material, the crystal was grown by physical vapor transfer (PVT) method using self-developed crystal growth furnace.
③ ingot processing. The obtained silicon carbide crystal ingot was orientated by X-ray single crystal orientator, then ground and rolled, and processed into standard diameter silicon carbide crystal.
④ Crystal cutting. Using multi-line cutting equipment, silicon carbide crystals are cut into thin sheets with a thickness of no more than 1mm.
⑤ Chip grinding. The wafer is ground to the desired flatness and roughness by diamond grinding fluids of different particle sizes.
⑥ Chip polishing. The polished silicon carbide without surface damage was obtained by mechanical polishing and chemical mechanical polishing.
⑦ Chip detection. Use optical microscope, X-ray diffractometer, atomic force microscope, non-contact resistivity tester, surface flatness tester, surface defect comprehensive tester and other instruments and equipment to detect the microtubule density, crystal quality, surface roughness, resistivity, warpage, curvature, thickness change, surface scratch and other parameters of silicon carbide wafer. According to this, the quality level of the chip is determined.
⑧ Chip cleaning. The silicon carbide polishing sheet is cleaned with cleaning agent and pure water to remove the residual polishing liquid and other surface dirt on the polishing sheet, and then the wafer is blown and shaken dry by ultra-high purity nitrogen and drying machine; The wafer is encapsulated in a clean sheet box in a super-clean chamber to form a downstream ready-to-use silicon carbide wafer.
The larger the chip size, the more difficult the corresponding crystal growth and processing technology, and the higher the manufacturing efficiency of downstream devices, the lower the unit cost.
Post time: Nov-24-2023