Hierarchical patterning for fabrication of advanced structures for few nm node devices and photonics using block copolymer lithography

Description

Traditional lithography methods such as UV photolithography, e-beam and nanoimprint lithography (NIL) are used for fabrication of devices for electronics and photonics. These lithography methods are used for patterning by either subsequent subtractive or additive techniques. In the near future, these methods have limitations due to inherent system capabilities and the resist materials. Hence, the feature sizes are challenging to miniature below sub-20 nm on large scale with these methods. Further reduction of the feature size calls for significant advancement in lithographic tools. Currently, the next-generation lithography solutions are being investigated among extreme-UV lithography (EUV) and direct e-beam writing to realize ultra- small feature sizes. However, most of these are challenging for high volume manufacturing due to their cost, considerable manufacturing time and lack of suitable lithographic resist materials. Therefore, alternative patterning techniques are investigated to resolve above issues.
Block copolymer (BCP) lithography is a promising candidate for wafer scale patterning. However, BCP lithography is not an alternative to traditional lithography on its own but serves as a complimentary patterning technique. Thin films of self-assembled architectures of BCPs have been investigated to generate various specific device structures. The BCPs that are most commonly used are based on polystyrene as one of the blocks, covalently coupled with polyethylene oxide, polymethylmethacrylate,polylactic acid, polyvinylpyridine or polydimethylsiloxane (PS-b-PEO, PS-b-PMMA, PS-b-PLA, PS-b-PVP or PS-b-PDMS) as the other block. BCPs have versatile applications depending on their molecular weight and characteristic properties. As examples of our work with BCPs we present low molecular weight BCP as a patterning precursor for fabrication of sub-10 nm FinFETs, sub-10 nm 2D materials and optical nanofin structures. Alternatively, larger structures by high molecular weight BCPs can be effectively used for fabrication of hard mask, antireflection, metal and III-V nanostructures.

Period	13 Mar 2019
Held at	Lund University, Faculty of Engineering, Finland
Degree of Recognition	International