Advanced Design of Block Copolymers for Nanolithography

Directed self-assembly ( DSA ) of block copolymer ( BCP ) has been identified as the potential strategy for the next-generation semiconductor manufacturing. The typical representative of the first generation (G1) of block copolymer for nanolithography is polystyrene-block-polymethylmethacrylate ( PS-b-PMMA). DSA of PS-b-PMMA enables limited half pitch (0. 5L(0) ) of 11 nm due to the low Flory-Huggins interaction parameter (chi). The second generation (G2) of BCP is developed with the feature of high chi. Solvent anneal or top-coat is employed for the G2 BCP to form the perpendicular lamellae orientation. Towards industry friendly thermal anneal, high chi BCP with equal surface energy (gamma) is reported as the third generation ( G3) BCP. Recently, based on Materials Genome Initiative (MGI) concept, optimized design of block copolymers with covarying properties ( G4 ) for nanolithography is presented to meet specific application criteria. G4 BCP achieves not only high chi and equal gamma, but also high throughput synthesis, 4 similar to 10 nm half pitch patterns, and controlled segregation strength. This review focuses on the advanced design of G3 and G4 BCP for nanolithography. Moreover, the challenges and opportunities are discussed for the further development of DSA of BCP.