The Metal Sputtering system (tool #6) is also a Temescal BJD 1800 system. Material is deposited by bombarding a target with energetic ions (typically Ar+). Atoms on the surface of the target are knocked loose and delivered to the substrate, resulting in deposition. Electrically conductive materials can be deposited by a dc power source in which the target acts as a cathode and the substrate(s) are mounted on a system anode. Deposition of dielectric materials requires an RF power source to deliver energy to the argon atoms. Sputtering can also be used to etch a material as a method of cleaning the substrate prior to film deposition. The etching process by sputtering can be thought of as a reversal of the sputter deposition process. With this method, almost any material can be deposited and the control is good, but the deposition rates are rather low.