Helium ion active hybrid non-chemically amplified resist (n-CAR) for sub-10 nm patterning applications

Patterning of the resist features down to 10 nm node is crucial for futuristic integrated circuits (ICs) technology advancements. In this regard, we design and developed a novel hybrid non-chemically amplified resist (n-CAR) i.e. MAPDST-co-ADSM (where MAPDST = (4-(methacryloyloxy)phenyl) dimethylsulfonium trifluoromethanesulfonate and ADSM = (acetyldibutylstannyl methacrylate)) for high-resolution Helium Ion (He+) Beam Lithography (HIBL) studies. The developed resist exhibits the high sensitivity toward Helium ion radiation and patterned sub-15 nm features at the dose ∼50 μC/cm2 onto negative tone resist formulation. In order to recognize the critical dimension (CD), the resist thin films were analyzed for single pixel exposure dose analysis at He+ exposure dose ranging from ∼30 pC/cm to ∼100 pC/cm. These investigations apparently reveal that 10 nm single pixel line features of the MAPDST-co-ADSM resist is patterned with the dose ∼50.48 pC/cm. The improved patterning resolution of the resist down to 10 nm is due to the inclusion of hybrid tin sensitizer in the resist structures. The MAPDST-co-ADSM showed coherent line edge roughness (LER) and line width roughness (LWR) values for 15 nm lines features as ∼1.67±0.27 nm and ∼2.20 nm respectively. Monte Carlo-based simulation technique is a standard method for statistical analysis and modelling of stochastic processes; such as noise in circuits, carrier transport and study of ion implantation/interaction/trajectory on materials for integrated circuits. Thus Monte Carlo ion trajectory simulation for MAPDST-co-ADSM resist formulation showed that the negligible (∼0.5%) target damage and recoil generation (atom displacement) of total energy delivered to the system (MAPDST-co-ADSM/Si) in novel HIBL exposure due to much larger stopping power of He+ ion and low proximity effect.