A NEW TECHNIQUE FOR DIAGNOSTICS OF A RADIOFREQUENCY PARALLEL-PLATE REMOTE PLASMA

A new parallel-plate remote plasma reactor was developed, containing a metal grid between the powered and the grounded electrode. Plasma parameters between the grid and a substrate holder have been measured in radio-frequency (13.56 MHz) argon plasmas using another grid with large surface area as a positive electrostatic probe. The electron density is lower than 10(6) cm-3 at rf power lower than 10 W; this demonstrates that the plasma is effectively confined. The electron energy distribution function is well approximated to a Maxwellian one. The electron temperature decreases as the pressure increases, and it is lower than 3 eV at pressures above 13.3 Pa, in agreement with electron temperatures in conventional plasmas.