Method for forming minute openings in semiconductor devices

Abstract

A method is disclosed for creating a sub-minimum opening in a semiconductor device, comprising the steps of: a) providing a first layer; b) providing a second layer over said first layer; c) providing a third layer over said second layer; d) providing a photoresist mask over said third layer; e) etching said third layer to form defined structures; f) depositing a fourth layer for forming spacers; g) etching said fourth layer to form said spacers; and h) etching said first layer to form an opening in said first layer. In etching the fourth layer to form the spacers, the third layer is generally etched away to form an opening to the first layer, and, in the following step, an opening (or feature) can be etched on the first layer. Generally speaking, the first and third layers can be of any material and should have similar etching rate; the second and fourth layers can be of any material and should have similar etching rate. However, the material for the first and third layers versus the material for the second and fourth layers should have highly dissimilar etching rates. Materials for these layers include and are not limited to polysilicon, oxide, nitride, and metal.