Planar inductively coupled plasmas operated with low and high radio frequencies

Planar inductively coupled plasmas (ICPs) powered with 13.56 MHz radio frequency (RF) are used increasingly by the semiconductor industry for close-coupled etching processes. Two planar ICPs operated with 0.46 and 13.56 MHz RF are described. Low-pressure argon discharges are compared in the same vacuum chamber. The two planar ICPs generate nearly identical plasmas, within experimental uncertainties, for similar gas pressures and RF powers. The ICP operation proves significantly easier with low RF frequency.