Trough adjusted optical proximity correction for vias

Abstract

A trough adjusted optical proximity correction for vias which takes into account the topography on a wafer created by prior processing. The vias are classified into one of two groups, coincident vias which have an edge coincident with an edge of the trough, and noncoincident vias which do not have an edge coincident with an edge of the trough, by analyzing the via and trough designs. Any coincident via is marked as valid for an optical proximity correction (OPC). Any noncoincident via is marked invalid for OPC. OPC is then performed to the via level. Only vias marked as valid for OPC will keep the correction. All other vias will keep their original design size. Alternatively, coincident vias can be simply treated differently from noncoincident vias. For instance, coincident vias can be subjected to an aggressive OPC correction, while noncoincident vias are subjected to a less aggressive OPC correction.

Dependencies are inferred from the claim text.