The CD requirements for the 45nm-node will become tighter so as it will be difficult to achieve with 65nm node
technologies. In this paper, a method to improve resolution by using DRECE (Dry-etching Resistance Enhancement
bottom-Coating for Eb) will be described. After all, DRECE has five times as high dry-etch resistance than the EB resist,
and this enables to accept higher anisotropic dry etching condition. By optimizing dry etching conditions, the CD
iso-dense bias dropped to 1/3 and the CD shift was reduced to 1/2. Also, there was no negative effect to CD uniformity.
From these results, we propose the use of DRECE for the 45nm-node technology.
The mask-making process for 45nm-node and beyond demands higher resolution and CD accuracy. To meet the requirements, the multi-layer resist system is developed as one of the solutions. BIL (Bottom Insulating Layer) can correct the profile of CAR (Chemically Amplified Resist). CAR shows profile degradation by photo-acid loss at the boundary of chrome and resist. The photo-acid loss induces excess footing in positive-tone CAR and under-cutting in negative-tone CAR. BIL reduced the profile degradation to less than half of the conventional resist system. BIL requires no extra mask process steps. Final CD linearity of isolated lines was improved by BIL. It is very beneficial for the patterning of sub-resolution assist features. Moreover, BIL with a hard-mask layer showed superior dry-etching bias performance.