Method for forming a via contacting several levels of semiconductor layers

摘要

A method for forming a via connecting a first upper level layer to a second lower level layer, both layers being surrounded with an insulating material, the method including the steps of: a) forming an opening to reach an edge of the first layer, the opening laterally continuing beyond said edge; b) forming a layer of a protection material on said edge only; c) deepening said opening by selectively etching the insulating material to reach the second lower level layer; and d) filling the opening with at least one conductive contact material.