Plasma characteristics of large area inductively coupled plasma system using ferrite-module-enhanced U-type antenna

Aferrite-module-enhanced internal-type linear inductively coupled plasma (ICP) source having multiple U-type antennas operated at 2 MHz has been proposed as a promising candidate to serve as an efficient high-density plasma source for plasma processing areas larger than 2,000 × 2,300 mm². When the ICP source was operated at 2 MHz RF power with the ferrite module, high density plasmas on the order of 2.9 × 10¹¹ cm^-3 were obtained at 10 mTorr Ar by applying 4 kW RF power/one U-type antenna; this is 1.5 times higher than the densities obtained at 13.56 MHz without the ferrite module. The higher plasma density obtained with the ICP source operated at 2 MHz with the ferrite module compared with that operated at 13.56 MHz without the ferrite module is related to the magnetic field enhancement caused by the ferrite module. The etch uniformity on a substrate of 2,300 × 2,000 mm² at 15 mTorr Ar/O2 (7: 3) and about 2.3 kW/U-type antenna was about 11%.