Site based quantification of substrate topography and its relation to lithography defocus and overlay

摘要

A method and system for modeling and analyzing wafer nanotopography data utilizes a nonlinear contact finite element model. Inputs to the model include lithography chuck parameters and site-based geometry data. Outputs from the model include in-plane distortions and out-of-plane distortions, from which defocus and overlay can be derived.

主权项

1. A method for evaluating metrological characteristics of a semiconductor substrate, the method comprising:
measuring, utilizing an optical measurement system, nanotopography (NT) of at least one of: a front surface, a back surface, and a thickness of said substrate; dividing said substrate into evaluation areas/sites; modeling effects of said NT on lithography process parameters utilizing a three-dimensional (3-D) finite element model, wherein said 3-D finite element model utilizes wafer parameters and chuck parameters as inputs and simulates wafer response on a lithography chuck during lithography processing, and wherein outputs from said 3-D finite element model include an out-of-plane distortion (OPD) and an in-plane distortion (IPD) on an individual site basis.