Abstract:
Thin film sputtering on the desired substrate is one of an industrial application that
needs to split atoms of sputter gas, such as Argon (Ar), to ions and electrons. This can be
done by plasma driven circuit that delivers a high frequency sinusoidal current waveform to
the sputtering machine. For the reason of high efficiency (more than 70% at 100-500 W)
with high frequency sinusoidal current waveform, this paper presents an application of halfbridge
class D series-parallel resonant inverter for plasma-driven circuit. In order that the
inverter can operate at zero voltage turn-on switches (ZVS), the resonant frequency ( fO )
of resonant tank is set below switching frequency ( f ). However, the vacuumed chamber
of sputtering system has a complicated physical structure, so that a simply load model is used
together with an ideal model of matching impedance transformer. The design concept is
realized by 194.9 W of prototype with 77.3% of efficiency at 100 kHz switching frequency.
Under environment of Argon gas, the experimental results verify that the prototype can
sputter thin film of material target; which here is Titanium, on glass slide.