Planar inductively coupled plasmas operated with low and high radio frequencies

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