African Quartz Semiconductor intends to establish a semiconductor wafer manufacturing plant to produce and growing semiconductor ingots to be transformed in semiconductor wafers.
To grow an ingot, the first step is to heat the silicon to 1420°C, above the melting point of silicon. As the seed is slowly lifts above the melt, the surface tension between the seed and the melt causes a thin film of the silicon to adhere to the seed and then to cool. While cooling, the atoms in the melted silicon orient themselves to the crystal structure of the seed. After passing several inspections, the ingot proceeds to slicing. Because of the silicon’s hardness, a diamond edge saw carefully slices the silicon wafers, so they are slightly thicker than the target specification. After the wafers have been sliced, the lapping process begins. Lapping the wafer removes saw marks and surface defects from the front and backside of the wafer. It also thins the wafer and helps to relieve stress accumulated in the wafer from the slicing process. After rounding the edges, depending on the end user’s specification, oftentimes the edges will go through an extra polishing step, improving overall cleanliness and further reducing breakage up to 400%.