Performance of Cr mask for extreme-ultraviolet lithography

Recently, extreme ultraviolet lithography (EUVL) becomes to be a candidate for the next generation lithography (EUVL) becomes to be a candidate for the next generation lithographic technology form 70 nm down to 35 nm. In this technology, multilayer films coating on the thick glass substrate is used. We have proposed the Cr absorber mask for EUVL using wet process. Cr absorber has been generally used as photomask, and been also supposed to be a promising material as absorber for EUVL mask because of its both high extreme ultraviolet (EUV) contrast and excellent chemical durability. The mask absorber pattern typically including the patterns of 0.35micrometers width lines and spaces (L&S) has been completely fabricated without degradation of the multilayer. Furthermore, the fine patterns width of less than 0.15micrometers have been successfully fabricated in the entire mask area of the 4-inch-diameter wafer. The EUVL mask has been evaluated with the EUVL laboratory tools at the beamline BL3 at the NewSUBARU synchrotron radiation facility. Line and spaces pattern width of less than 0.1micrometers are clearly replicated and isolated lines pattern width of 40nm are also replicated. We confirmed that the mask absorber pattern fabrication process using a wet process is useful for EUVL mask.