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Selective Neutralization for Neutral Last Grapho-Epitaxy Directed Self-Assembly

IP.com Disclosure Number: IPCOM000240420D
Publication Date: 2015-Jan-29
Document File: 3 page(s) / 301K

Publishing Venue

The IP.com Prior Art Database

Abstract

Disclosed is a process that achieves selective neutralization of the bottom surface of a hard grapho-epitaxy template. Selective neutralization is achieved by coating a selective neutral brush after template formation, and Directed self-assembly (DSA) is achieved with a neutral last process using a range of different template materials and template formation (e.g., plasma etch) processes.

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-Assembly

Assembly

Directed self-assembly (DSA) is a technique for forming sublithographic line/space patterns utilizing the phase separation of block copolymers . In order to form vertically oriented line-space patterns with block copolymer domains, a neutral layer must be present at the bottom of the block copolymer layer . This imposes restrictions on using only soft materials and gentle processes, such as photoresists and development, for template formation in order to preserve the properties of the underlying neutral layer .

Conventional neutral layers are a polymer that grafts on the hard mask or a cross -linked layer of polymer.

Prior art shows grapho-epitaxy on a weak preferential template (i.e. slightly non-neutral)

Selective Neutralization for Neutral Last Grapho - -Epitaxy Directed Self

Epitaxy Directed Self -

with a uniform surface treatment for both the bottom and sidewall surfaces . However, this shows that non-neutral bottom surfaces can cause domain flipping . Other approaches use cylinder phase block copolymers to avoid the requirement for a neutral bottom surface, but line edge roughness and bridging problems are more severe with cylinder phase block copolymers.

The novel contribution is a process that achieves selective neutralization of the bottom surface of a hard grapho-epitaxy template. Selective neutralization is achieved by coating a selective neutral brush after template formation . DSA is achieved with a neutral last process using a range of different template materials and template formation (e.g., plasma etch) processes.

This technique enables the use of an etched template for line /space grapho-epitaxy. This can decouple template lithography, template stack, and etch processes from the DSA formation process. This means that Extreme Ultraviolet (EUV) lithography, etch trim processes, and sidewall image transfer (SIT) can now be used for pattern DSA templates.

The selective neutral process requires a type of surface treatment brush that partially grafts substrate surf...