Microwave multipolar plasmas: a possible solution for etching in microelectronics?

Abstract

The fulfilment of the increasingly stringent requirements for selectivity and anisotropy in etching relies on absolute control of the interaction between a plasma and the substrate being processed. In the present study, the way in which the working point of radiofrequency capacitive discharges determines this interaction is shown and the definition of etching processes is seen to be the result of necessary compromises. Improved etching control can be obtained using multipolar magnetic field confinement discharges, which produce large volumes of low-pressure homogeneous isotropic quiescent DC plasma. So far, the field of application of these hot-cathode-generated plasmas has been limited to non-corrosive gases. A microwave discharge used in association with multipolar magnetic field confinement produces plasmas exhibiting the characteristics required for accurate etching control.