Helicon plasma source for ionized physical vapor deposition

Abstract

Abstract A helicon antenna that sits remotely outside the vacuum system is attached to a magnetron sputtering system. This increases the electron temperature, which increases the ionization of the sputter flux for achieving ionized physical vapor deposition (IPVD). There are no shadowing and contamination problems, unlike other IPVD devices with immersed coils, since the helicon antenna is outside the vacuum system. Furthermore, the target to substrate distance can be kept small. At 2 kW magnetron power, 4 kW helicon power, 45 mTorr argon gas, and with a copper target, ionization fractions to the substrate of 51±10% and a deposition rate of 847±42 A/min are measured using a quartz crystal oscillator (QCO) and a multi-grid filter. Without the antenna, the ionization fraction to the QCO is 30±6% and the deposition rate is 815±41 A/min. Multiple remote sources are envisioned to be positioned radially around a sputtering chamber, controlling uniformity while increasing the ionization further. Since 21% additional ionization is achieved using only one source, with no threat of contamination inside the vacuum chamber, the helicon source has good potential for a secondary plasma source in IPVD applications.