The present invention relates to a plasma processing device, and in particular to a plasma processing device using a cathodic arc discharge.
In recent years, study of a thin film deposition technique using a low pressure arc discharge has been vigorously conducted. In such a technique, an arc discharge is generated by bringing an electrode generally called striker in mechanical contact with a target portion serving as a cathode or by using an electron beam to let an arc current of several tens amperes flow into the target portion. Plasma is sustained by making ions from plasma hump generated in an upper space of the target collide with the cathode and thereby generating ions and electrons from the cathode. Plasma including these ions and electrons is efficiently led to a vacuum reaction chamber by using a magnetic field duct for transportation and a magnetic field duct for scanning. The plasma is thus applied uniformly to a substrate to be processed. Thereby, processing such as thin film forming or etching is conducted.
When plasma is generated by an arc discharge in the above described conventional method, however, a large number of neutral particles having no electric charge or electrically charged particles are generated besides ions and electrons. These hamper the processing such as thin film forming or etching as particles, resulting in a great problem.