Impact of Polarization Inside a Resist for ArF Immersion Lithography

Abstract

Immersion technology with new lens materials and new high-refractive fluids is the key technology to extend the resolution capability of existing 193-nm lithography below the 32-nm pattern formation, but it faces more pronounced polarization and reflection control issues. In this paper, for a wet system, the propagations of the transverse electric (TE) and the transverse magnetic (TM) waves inside a one-layer resist and a multi-layer resist are described by using the finite-difference-time-domain (FDTD) method with a multi-layer model and a transfer-matrix model, respectively. In the comparison with a dry system, the TE and the TM modes of the wet system are larger than those of the dry system. Inside the multi-layer resist, the TM and the TE modes change little at incident angle below 20 degrees. However, for a 45-nm pattern formation, no difference between the TM and the TE modes is found under the given conditions for incident angles below 20 degrees.