A high-quality finished surface is essential for mass production of novel power SiC-based semiconductor devices. As device manufacturers search for ways to increase productivity, they look to reduce both the number and the duration of grinding and polishing steps.
State-of-the-art SiC wafers are pre-processed via several cycles of lapping or mechanical diamond polishing followed by Chemical Mechanical Polishing (CMP), processes that entail many steps and high machining costs because of their slow material removal rates. To reduce consumable costs, grinding with a consolidated diamond abrasive technology is currently considered the preferred alternative to lapping.
Comparison of standard lapping processes vs Meister course and ultra-fine grinding technologies.
Meister's innovative SiC Ultra Fine 6 (UF6) grinding wheel technology can help prime wafer and device manufacturers shorten wafer preparation steps to the minimum. The ultra-smooth surface profile achieved with this method enable manufacturers to avoid diamond slurry costs, reduce CMP cost tremendously and drastically increase throughput.
Furthermore, the highly porous open structure of the unique bond technology enables manufacturers to use low-force grinding processes that improve wafer geometry (TTV, bow and warp) and decrease surface roughness even further.
Despite the well-known hardness, stiffness and strength of monocrystalline SiC, Meister has developed ultra-fine grinding technologies that assure sub-nm average surface roughness (Ra) and sub-µm Total Thickness Variation (TTV) values on 4", 6" and 8" SiC wafers. The novel technology, based on a fixed Meister Abrasives bond-grit formulation, targets best-in-class, low-cost and high-quality finished SiC wafer surfaces.
Grinding wheels manufactured with this formula can accomplish ultra-smooth SiC (Ra = 0.5 nm and TTV < 1 µm) surfaces because of their unique bonding structure and tailored grit size. Additionally, SiC wafers ground with these wheels exhibit reduced crystal damage, mirror-like surface and improved wafer geometry while maintaining low grinding forces and wheel wear.
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