Silicon must turn into a wafer before silicon wafer polishing and before a semiconductor can be built. This process begins with growing a silicon ingot. Growing a silicon ingot can take anywhere from one week to one month, depending on a variety of factors, including quality, size, and the specification. Here’s a closer look at silicon wafer processing and precisely how they are made.
Ingot Growth
The first step to grow an ingot is to heat the silicon to 1420°C. This is above the melting point of silicon and long before silicon wafer polishing. Once the dopant combination and polycrystalline has been liquefied, the seed, a single silicon crystal, is positioned on top of the melt, barely touching the surface. The seed has the same crystal orientation required in the finished ingot.
Slicing
After the ingot is fully-grown, it is ground down to roughly a diameter that is slightly larger than the target diameter of the final silicon wafer. After being passed through several inspections, the ingot goes to slicing next. With silicon wafer polishing not far off, the silicon is sliced. Due to the silicon’s hardness, a diamond edge saw is needed to carefully slice the silicon wafers to a width slightly thicker than the target specification.
Cleaning
The final and most critical step in the manufacturing process is silicon wafer polishing. This process takes place in a cleanroom. To maintain cleanliness, workers must wear cleanroom suits that cover their bodies and do not collect any particles. They also stand under a fan that blows away any small particles that might have accumulated before entering the room.
