METHOD AND APPARATUS FOR DETERMINING A PHOTOLITHOGRAPHY PROCESS MODEL WHICH MODELS THE INFLUENCE OF TOPOGRAPHY VARIATIONS

摘要

One embodiment provides a system for determining a process model for a photolithography process. The photolithography process can use multiple exposure and development steps to create features on a wafer. When the photolithography process exposes the wafer to a layout, the wafer can include topography variations which were caused by previous exposure and development steps. The process model can be used to predict patterns that are created on the wafer when the wafer is exposed to a second layout, wherein the wafer includes topography variations that were caused by resist features that were created when the wafer was exposed to a first layout. The process model can include a first term and a second term, wherein the first term is convolved with a sum of the first layout and the second layout, and wherein the second term is convolved with the second layout.