NOVELTY - The method of cleaning chambers using fluorine (F2) containing 1-2 wt.% of hydrogen fluoride (HF), is claimed. The F2 is obtained by step (I) and step (II). The step (I) comprises: (A) electrolytically producing raw F2 from HF in the presence of potassium fluoride (KF) using an electrolyzer; (B) removing particles entrained in the raw F2; (C) filtering any remaining particles out of the F2 using a metallic filter; and (D) providing F2 to a buffer tank or a storage tank. The step (II) comprises withdrawing F2 from the buffer tank or the storage tank and then delivering to a chamber.    USE - The method is useful for cleaning chambers such as chemical vapor deposition chamber that is useful in manufacture of a semiconductor, a micro-electromechanical system, a thin film transistor flat panel display or a solar cell for depositing a layer (all claimed).    ADVANTAGE - The method is capable of economically cleaning the chambers using less equipment with reduced steps and less energy consumption and high degree of safety.    DETAILED DESCRIPTION - The method of cleaning chambers using fluorine (F2) containing 1-2 wt.% of hydrogen fluoride (HF), is claimed. The F2 is obtained by step (I) and step (II). The step (I) comprises: (A) electrolytically producing raw F2 from HF in the presence of potassium fluoride (KF) using an electrolyzer; (B) removing particles entrained in the raw F2; (C) filtering any remaining particles out of the F2 using a metallic filter; and (D) providing F2 to a buffer tank or a storage tank. The step (II) comprises withdrawing F2 from the buffer tank or the storage tank and then delivering to a chamber to perform a chamber cleaning. The particle filter of step (C) comprises pores having a diameter of less than 10 mu m. The step (B) is performed in a static scrubber. The electrolyzer, the static scrubber, the metallic filter, the buffer tank or the storage tank, and the chamber are operably connected. The F2 pressure in step (A) is less than or equal to 1.05 plus minus 0.02 bar (abs). The F2 is delivered to the chamber in step (II) at a pressure of 0.2-0.55 bar (abs). An INDEPENDENT CLAIM is included for a process for manufacturing fluorine.    DESCRIPTION OF DRAWING(S) - The diagram shows a schematic view of a plant for providing fluorine. (1, 2, 3, 4) Line #(5) First filter #(6) Second filter #(7) Valve.