BEHAVIOR OF PLASMA FORMED IN A PAGODA-SHAPED RADIO FREQUENCY PLASMA SOURCE

A large volume, high density, and pagoda-shaped radio frequency (rf) plasma source has been developed for use in large scale plasma processing. The inductively coupled plasma (ICP) is created by a pagoda-shaped 13.65 MHz antenna to improve the plasma uniformity on substrate. Plasma densities and electron temperatures are measured by using a Langmuir probe and their radial and axial profiles are attained. Electron density of >1×10¹¹ cm^-3 on the substrate and uniform to \leqslant±1.6% over 16 cm diameter can be produced at argon pressure of 6.65×10^-1 Pa and input rf power of 1 kW. ICP etching photoresist in O₂ plasma has been tested and the etching uniformity consists with that of the plasma density on the substrate. A large scale etched sample with the uniformity to \leqslant±1.1% over 10 cm diameter or to \leqslant±2.2% over 13 cm diameter has been obtained.