2014 Volume 27 Issue 5 Pages 639-644
Extreme ultraviolet (EUV) lithography is a candidate for the manufacturing of semiconductor devices at the 22 nm half pitch node and below. EUV lithography requires high performance resist with limited outgassing property. The key challenge for EUV resist is the simultaneous requirement of ultrahigh resolution (R), low line edge roughness (L) and high sensitivity (S) for lines and spaces (LS) features. To achieve high sensitivity, containing fluorine atom is one of the popular methods because the fluorine atom absorbs EUV light strongly. However, when the resist polymer has fluorine atom, the contact angle (CA) of the resist becomes high. It is difficult to rinse high CA resist so the containing fluorine atom have a problem of defects. In this paper, we will report the relationship of line edge roughness and acid diffusion length and the method to diminish defects caused by high CA. We achieved good resolution and LER improvement by controlling acid diffusion length. Moreover, we found the relationship of the number of defects and the structure of the monomers containing fluorine units.
