Dependence of driving frequency on capacitively coupled plasma in CF4

A radio-frequency CF4 plasma in reactive-ion etcher with parallel plate geo metry is investigated in one dimension at a position space using the relaxa tion continuum model. The discharge with negative ions has the double layer similar in appearance to O-2; the structure and mechanism are markedly cha nged as a function of driving frequency. The effect of driving frequency is numerically studied between 13.56 MHz and 200 MHz for 200 mTorr and 50 mTo rr. In these studies, the plasma density is kept constant at similar to 10( 11) cm(-3), considering the charged species CF3+, CF2+, CF+, C+, F+, F-, an d electrons. The mean energy of charged particles is also discussed.