8 August 1993 New resolution-enhancing mask for projection lithography based on in-situ off-axis illumination
Author Affiliations +
A new technique has been developed for the illumination of a mask in a wafer stepper. A phase-shifting layer (a so-called kinoform) is introduced in the optical path of the projection system between the last lens of the illumination system and the mask absorber. This phase- layer interacts with the incident light in such a way, that the features on the mask get a specific optimized illumination. Therefore the phase distribution has to be generated under consideration of the feature size and distribution on the mask. In that sense a mask feature customized illumination is obtained. In a first application phase, the phase layer is created on the glass side of the mask. Linear as well as chessboard phase gratings are applied. With a chessboard phase grating, a quadrupole-like illumination is generated, which can be optimized to the mask feature distribution by choosing the correct grating frequency, phase-shift and tilt.
© (1993) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Rainer Pforr, Rainer Pforr, Rik M. Jonckheere, Rik M. Jonckheere, Wolfgang Henke, Wolfgang Henke, Kurt G. Ronse, Kurt G. Ronse, Patrick Jaenen, Patrick Jaenen, Ki-Ho Baik, Ki-Ho Baik, Luc Van den Hove, Luc Van den Hove, } "New resolution-enhancing mask for projection lithography based on in-situ off-axis illumination", Proc. SPIE 1927, Optical/Laser Microlithography, (8 August 1993); doi: 10.1117/12.150424; https://doi.org/10.1117/12.150424


Back to Top