Patent ID: 8195435

Claim:
A method of generating a modeled angular spectrum of diffracted orders for at least a portion of a diffracting photolithographic mask including a patterned absorber material disposed above a plurality of unpatterned layers forming a high and low refractive index (HL) quarter wave stack, the method comprising: calculating the modeled angular spectrum of diffracted orders resulting from modeled electromagnetic radiation incident to a hybrid model profile of the diffracting photolithographic mask portion, the hybrid model profile including a plurality of curved interfaces which varies with respect to a first dimension, each of the curved interfaces representing an interface between two adjacent unpatterned layers of the (HL) quarter wave stack, and a horizontal slab defined by two parallel interfaces which are constant with respect to the first dimension representing the patterned absorber material; and predicting how the diffracting photolithographic mask images onto a substrate based on the modeled angular spectrum of diffracted orders.