Plasma Characteristics of a Ni–Zn Ferrite Enhanced Internal-Type Inductively Coupled Plasma Source Operated at 2 and 13.56 MHz

Abstract

Plasma and electrical characteristics of an internal-type inductively coupled plasma source with a Ni-Zn ferrite module installed near the antenna were investigated for different rf power frequencies of 2 and 13.56 MHz. Due to the lower heating of the Ni-Zn ferrite module on the antenna for the operation at 2 MHz compared to the operation at 13.56 MHz, higher plasma density and lower rf rms antenna voltage were resulted for the operation at 2 MHz in addition to more stable plasma characteristics. By the application of 500 W of rf power to the source, a high plasma density of 8 9 10 11 cm -3 which is about four times higher than that with 13.56 MHz could be obtained at the pressure of 10 mTorr Ar. When photoresist etch uniformity was measured for the operation with 2 MHz by etching photoresist on a 300 mm diameter substrate using 10 mTorr Ar/O 2 (9:1) mixture, the etch uniformity of about 5.5% could be obtained.

Plasma Characteristics of 450 mm Diameter Ferrite-Enhanced Inductively Coupled Plasma Source

“…Ferrite modules installed above an ICP antenna can reinforce the induced time-varying magnetic field below the antenna and can change the plasma characteristics of the ICP source. 7) The schematic diagram of the large-area ICP system used in this experiment is shown in Fig. 1(a).…”