Contact hole reticle optimization by using interference mapping lithography (IML)

The theory of interference mapping lithography (IML) is presented for low k 1 (k 1 1 =0.39) contacts was created and exposed on an ASML /1100 ArF scanner using NA of 0.75 and Quasar illumination (σ in =0.72, σ out =0.92, span angle=20°). Measurements on the exposed wafers show that IML CPL results in printing 100nm contacts through pitch (200nm minimum pitch to isolated) with 0.45μm DOF at 10% EL.