We have investigated a number of key resist factors using EUV lithography including
activation energy of deprotection. Our standard high activation resist material, MET-2D
(XP5271F), is capable of robust performance at CDs in 40 nm regime and thicknesses above 100
nm. Below 100 nm film thickness, controlling acid diffusion becomes a difficult challenge.
We have also developed a low activation resist (XP6305A) which shows superior process
window and exposure latitude at CDs in the 35 nm regime. This resist is optimal for 80 nm
film thickness. Lastly, we have demonstrated 25 nm 1:1 resolution capability using a novel
chemical amplification resist called XP6627. This is the first EUV resist capable of 25 nm
resolution. The LER is also very low, 2.7 nm 3&sgr;, for the 25 nm features. Our first version,
XP6627G, has a photospeed of 40 mJ/cm2. Our second version, XP6627Q, has a photospeed of
27 mJ/cm2. Our current focus is on improving the photospeed to less than 20 mJ/cm2. The
outstanding resolution and LER of this new resist system raises the possibility of extending
chemically amplified resist to the 22 nm node.