Influence of optical filtering and coherence parameter on the 3-D line spread function in photolithographic imaging

Influence of optical filtering and coherence parameter on the 3-D line spread function in photolithographic imaging. Two of the goals in photolithography imaging are to obtain high resolution and also great depth of focus. In this paper we discuss the possible application of different types of nonuniform transmission filters in photolithography. Since the smallest structures that can be produced by an optical system correspond to its response function we have discussed the 3-D line response. As the illumination in photolithography is partially coherent we have analysed the influence of the filters in the 3-D LSF for different coherence parameters.