Inductively coupled parallel-plate plasma reactor with a conical dome

Abstract

A plasma reactor appropriate for fabrication, especially etching, of semiconductor integrated circuits and similar processes in which the chamber has a top comprising a truncated conical dome and, preferably, a counter electrode disposed at the top of the conical dome. An RF coil is wrapped around the conical dome to inductively couple RF energy into a plasma within the chamber dome. The dome temperature can be controlled in a number of ways. A heat sink can be attached to the outside rim of the dome. A rigid conical thermal control sheath can be fit to the outside of the dome, and any differential thermal expansion between the two is accommodated by the conical geometry, thus assuring good thermal contact. The rigid thermal control sheath can include resistive heating, fluid cooling, or both. Alternatively, a flexible resistive heater can be wrapped around the dome inside the RF coil. The resistive heater includes a heater wire wound in a serpentine path that has straight portions overlying and perpendicular to the RF coil but has bends located away from the RF coil. The path prevents the heater wire from shorting the azimuthal electric field induced by the RF coil and also acts as a Faraday shield preventing capacitive coupling from the coil into the chamber plasma.