Disclosed herein are systems and methods for in-situ measurement of impurities on metal slugs utilized in electron-beam metal evaporation/deposition systems, and for increasing the production yield of a semiconductor manufacturing processes utilizing electron-beam metal evaporation/deposition systems. A voltage and/or a current level on an electrode disposed in a deposition chamber of an electron-beam metal evaporation/deposition system is monitored and used to measure contamination of the metal slug. Should the voltage or current reach a certain level, the deposition is completed and the system is inspected for contamination.