Patent ID: 7781349

Claim:
A method for setting up lithographic processing of a substrate, the method comprising using a stack comprising a number of bottom anti-reflective coatings in between a resist layer and the substrate thus creating a number of optical interfaces, the bottom anti-reflective coatings having at least a first bottom anti-reflective coating adjacent the resist layer and at least a second bottom anti-reflective coating adjacent the first bottom anti-reflective coating, comprising: selecting a real refractive index and an extinction coefficient of each of the bottom anti-reflective coatings such that an optical step at an interface resist/first bottom anti-reflective coating is smaller than an average optical step per interface for traversing from the resist to the substrate, the extinction coefficients of the bottom anti-reflective coatings are selected to be increasing at each optical interface when traversing from the resist layer to the substrate, and the real refractive indices of the bottom anti-reflective coatings are selected to be decreasing at each optical interface when traversing from the resist layer to the substrate.