Single Rare-Earth Ion Doped Tin-Oxo Nanocluster Photoresists for High-Resolution Extreme Ultraviolet Lithography

Rare-earth (RE) metals are known as industrial vitamins
and show
significant regulatory effects in many fields. In this work, we first
demonstrated that the vitamin effect of RE metals can also be applied
to extreme ultraviolet (EUV) lithography. Using a Sn8RE
oxo cluster as the universal platform, different individual RE metal
ions were successfully doped to obtain a series of isomorphic heterometallic
clusters (RE = Y, Sm, Eu, Ho, Er). Lithography experiments have shown
that the doped RE ions displayed a significant influence on technical
parameters. As a result, an electron-beam lithography (EBL) line width
of 11.95 nm was achieved by Sn8Er, and an EUV lithography
critical dimension (CD) of 15.90 nm was obtained by Sn8Ho under an exposure dose of 52.64 mJ/cm2. These findings
expand the applications of rare earths in high-precision semiconductor
manufacturing and provide a new strategy for the development of high-resolution
EUV photoresists.