Magnetron Enhanced Reactive Ion Etching in a Hexode System

A method of forming a uniform magnetic field in a modified hexode type etch system is described. Experimental results of etching Si, SiO2 and photoresist with NF3 are presented. The magnetic field effectively increases the ion flux and decreases the energy of the ions bombarding the cathode. It was found that adding a magnetic field increases the etchrate of Si for the conditions studied, but for SiO2 and photoresist, the decreased ion bombardment energy leads to lower etchrates under certain conditions. The resulting effect on selectivities is discussed.