During this reaction, the impurities such as Fe, Al, and B will react with HCl and form other substances. the SiHCl3 has a low boiling point of 31.8 C and distillation is used to purify the SiHCl3 from the impure halides. At last, SiHCl3 will react with hydrogen at 1100 C for 200 ~300 hours to produce a very pure form of silicon.
After pure silicon is produced, they will cut the silicon ingot into individual discs that are called wafers. Each wafer is about one mm thick. After that, the photolithography process begins. Most of the photolithography is based on Diazoquinones (DQ). There are few steps to finish the photolithography process.