Vikram K. Daga

Nanoparticle-Driven Assembly of Block Copolymers: A Simple Route to Ordered Hybrid Materials

The addition of nanoparticles that selectively hydrogen bond with one of the segments of a block copolymer is shown to induce order in otherwise disordered systems. This enables the fabrication of well-ordered hybrid materials with spherical, cylindrical, or lamellar domains at particle loadings of more than 40%, as evidenced by TEM and SAXS. The approach described is simple and applicable to a wide range of nanoparticles and block copolymers, and it lays the groundwork for the design of cooperatively assembled functional devices.

Photoinduced ordering of block copolymers.

Photoinduced ordering of disordered block copolymers (BCPs) would provide an on-demand, nonintrusive route for formation of well-ordered nanostructures in arbitrarily defined regions of an otherwise disordered material. Here we achieve this objective using a rapid and simple approach in which photoconversion of an additive blended with the BCP introduces strong interactions between the additive and one of the chain segments and induces strong order in the BCP blend. The strategy is generally applicable to block copolymers containing chain segments capable of hydrogen bonding with the additive.

Additive-loaded EUV photoresists: performance enhancement and the underlying physics

A series of molecular glasses (MGs) protected with multiple tert-butoxylcarbonylmethyl (tBCM) groups are employed as additives to enhance extreme ultra violet (EUV) photolithographic performance of a hydroxystyrene based Environmentally Stable Chemically Amplified Photoresist (ESCAP). The tBCM groups deprotect to form carboxylic acids that are capable of hydrogen bonding with chain segments of the polymer resist. This approach enables a systematic study of the governing physics underlying the improved lithographic performance. While MGs inhibit solubility in all cases, we find that differences in the structure of the MGs can significantly affect the photoacid diffusivity. In our ongoing optimization of the structure and loading of MGs, photoacid generators (PAGs), and base quenchers, 25 nm to 30 nm resolution has been achieved. The structure-property relationships and the synergistic effects of employing small, multi-functional additives in the polymeric photoresists are studied using various characterizations.