Metallic impurities having a lower ionization tendency than Si, such as Cu, are adsorbed onto the surface of the silicon substrate in hydrofluoric acid (HF) chemicals and buffered hydrofluoric acid (BHF) and then degrade device characteristics. A new purification method using a granular polysilicon (poly-Si) as an adsorbent was designed to remove the metallic impurities. As an adsorbent, Au deposited poly-Si (Au-poly-Si) was developed to improve the Cu removal efficiency of the poly-Si, and Au removed Au-poly-Si (Au-R-poly-Si) was also developed to prevent Au contamination from the Au-poly-Si. These poly-Si were more promising for HF than for BHF because of the difference in the etching rate of the silicon. The purification system using the Au-R-poly-Si was investigated using a 36 day running test. This system shows sufficient performance and reliability for reprocessing HF in a wet station at point-of-use. This purification method makes it possible to lengthen HF Lifetimes and decrease the amount of HF used in very large scale integration manufacturing.