Submicron patterns formed by reactive ion etching

A tri-level etching process based on polyimide as bottom layer, silicon nitride as intermediate layer, and PMMA resist as top layer is presented. The reactive ion etch process allows the transfer of submicron patterns from the PMMA into the PIQ with vertical sidewalls and high aspect ratios. The influence of pressure, gas flow, power and self bias voltage on the etching process will be described. Silicon dioxide patterns, which are fabricated by using a CHF sub 3 etching process with a polyimide mask, will be shown.