Studies of a magnetic null discharge plasma for sputtering application

A new type of plasma system based on the magnetic neutral loop discharge (NLD) concept has been developed for sputter application. This system is characterized by plasma production around the multi-null magnetic field on the electrode surface, where a capacitive RF electric field is applied. From the experimental results and numerical analysis of electron behavior in this system, we found that electrons around the magnetic null region on the target surface moved in meandering orbits like in the original NLD concept. Effective electron heating around the null region can be controlled by varying the magnetic flux density of magnets and their arrangement. In addition, by this new NLD sputter system, a Cu thin-film of 1 μm could be obtained under the condition of a RF power of 350 W, a gas (Ar) pressure of 1.8 mTorr and deposition time of 1 h.