The high-purity polycrystalline silicon raw material is placed in a high-purity quartz crucible and then melted by the high temperature generated by the graphite heater. Next, the molten silicon liquid is slightly cooled to produce a certain degree of sub-cooling. Subsequently, a single crystal of silicon (referred to as a seed crystal) fixed on the seed crystal axis is inserted into the surface of the melt. After the seed crystal and the melt are melted, the seed crystal is slowly pulled up, and the crystal grows at the lower end of the seed crystal. Then, the seed crystal growth is controlled to grow a narrow neck having a length of about 100 mm and a diameter of 3 to 5 mm. The neck is used to eliminate dislocations of atoms arranged by the intense thermal shock of the high temperature solution to the seed crystal. This process is crystal seeding.After that, the crystal diameter is enlarged to the size required by the process, typically 75 to 300 mm. This process is called shouldering. Then, suddenly increase the speed to perform the shoulder rotation operation, so that the shoulder is approximately right angle. Entering the equal diameter process, a single crystal cylinder of a certain diameter size is generated by controlling the thermal field temperature and the crystal lifting speed. After most of the silicon solution are crystallized,the crystal is gradually reduced to form a tail cone, which is called a finishing process. In this way, a single crystal drawing process is basically completed. After a certain heat preservation and being cooled, the single crystal is available to be taken out.