As technology pushes feature dimensions smaller, the effect of lens aberrations becomes more relevant. Therefore, it has become important that we completely understand the effects lens aberrations have on our product feature patterning. It also becomes important that we have a tool and a process that can accurately describe and measure the aberrations in our exposure systems. With our lens systems characterized and through use of a lithographic simulator, we can predict pattern placement, critical dimensions and intra-field overlay errors. It is the inclusion of aberration information in the simulator that has allowed us to predict across field placement and critical dimension effects on features in our designs. This paper looks at the use of an In-Situ Interferometer for measuring lens aberrations and characterizing the exposure systems for use in a lithographic simulator. The aberration data was used in conjunction with a simulator to predict pattern placement, critical dimension and intra-field overlay. Simulated overlay was compared to inline product overlay to investigate the accuracy of the aberration measurement tool and process. This paper extends work previously described to validate the simulation process for the 170nm technology node with multiple layer combinations investigated.