Pulsed inductively coupled plasmas as a method to recoup uniformity: Three-dimensional modeling study

High plasma density sources such as inductively plasmas (ICPs) are commonly used for microelectronics fabrication. Design constraints often result in systems which have asymmetric gas pumping which can in turn produce azimuthal nonuniformities in plasma properties. These asymmetries are reinforced by a positive feedback between nonuniformities in conductivity and power deposition. In this letter, we discuss computational results from a three-dimensional model for pulsed operation of ICPs sustained in argon as a means to recoup azimuthal symmetry of plasma properties which may result from asymmetric pumping. We found that azimuthally asymmetric plasma properties produced by continuous operation gradually become more uniform during pulsed operation due to the interruption of the positive feedback and allowing interpulse diffusion to smooth asymmetries.