Performance of a programmable illuminator for generation of freeform sources on high NA immersion systems

This paper describes the principle and performance of a fully programmable illuminator for a high-NA immersion system. Sources can be generated on demand, by manipulating an array of mirrors instead of the traditional way of inserting optical elements and changing lens positions. All mirrors are always used to create the source such that no light is lost when switching from one source shape to another. Measured sources generated with this new type of illumination system will be shown and compared to the target sources generated by source mask optimization software or targets of traditional sources. Comparison between measured and target source will be done both in parameters of a pupil fit model and by simulated imaging impact. Also the first results in resist obtained on a XTIV 1950Hi 1.35 NA tool equipped with this illuminator are presented and compared to measurements on the same system when it was equipped with an Aerial XP illumination system.