Full scalar and vector models

In the full scalar model, the full light intensity inside the resist is calculated, subject to the standard scalar approximation, involving the requirement that the three components of the electric field vector be treated separately as scalar quantities, with each scalar electric field component satisfying the wave equation. In addition, when two fields of light (for example, two plane waves) are added together, the scalar approximation dictates that the sum of the field would simply be the sum of the scalar amplitudes of the two fields. Implicit in the scalar approximation is 

Levinson and W.H. Arnold, Focus the critical parameter for submicron lithography, J. Vac. Set Technol. B 5, 21 34 293 298 (1987) C.A. Mack, Optical lithography modeling, in Micro lithography Science and Technology, J.R. Sheats and B.W. Smith, Eds., pp. 120 121, Marcel Dekker, New York (1998). 

For the full vector model, the complete solution of Maxwell s equations is used, while accounting for the vector directions is required. This model is valid for all angles and numerical apertures. 

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