Study on Resist Performance of Polymer-Bound and Polymer-Blended Photo-Acid Generators

Abstract

In the fabrication beyond a 16 nm node, the uniform distribution of acid generators in a resist matrix is a serious concern. The incorporation of acid generators into polymers via covalent bonds has attracted much attention in overcoming the compatibility problem of acid generators with polymers and reducing the diffusion lengths of acids, which leads to a high resolution and a low line edge roughness (LER). Therefore, the resist performance characteristics of a polymer-bound photo-acid generator (PAG) and a polymer-blended PAG were investigated and compared. The numbers of acid molecules generated in the polymer-bound and polymer-blended PAGs upon exposure to extreme ultraviolet (EUV) were almost the same at both 5 and 10 mol % acid generator contents. However, the sensitivity of the polymer-blended PAG was higher than that of the polymer-bound PAG. Although the etching durabilities of the developed polymer-blended and polymer-bound PAGs were lower than that of conventional resist materials, the surface roughness of the polymer-bound PAG was lower than that of the polymer-blended PAG. The developed polymer-bound PAG resist showed an excellent performance (30 nm line and 80 nm pitch). Thus, it was proved that polymer-bound PAG resists are promising candidates for the resist materials of nanolithography, such as electron beam and EUV lithography.