Effect of antenna capacitance on the plasma characteristics of an internal linear inductively coupled plasma system

This study examined the effect of the antenna capacitance of an inductively coupled plasma (ICP) source, which was varied using an internal linear antenna, on the electrical and plasma characteristics of the ICP source. The inductive coupling at a given rf current increased with decreasing antenna capacitance. This was caused by a decrease in the inner copper diameter of the antenna made from coaxial copper/quartz tubing, which resulted in a higher plasma density and lower plasma potential. By decreasing the diameter of the copper tube from 25 to 10 mm, the plasma density of a plasma source size of 2750×2350 mm2 was increased from approximately 8× 1010 cm3 to 1.5× 1011 cm3 at 15 mTorr Ar and 9 kW of rf power.