Saturday, January 11, 2025

Integrating Metal-Oxide EUV Resists with Directed Self-Assembly for High-Resolution Chemical Patterning

Extreme ultraviolet (EUV) lithography struggles with resist materials that can deliver both high resolution and acceptable throughput, often resulting in rough patterns and printing defects that degrade semiconductor performance. To overcome this, researchers are exploring directed self-assembly (DSA) of block copolymers (BCPs), which can naturally rectify pattern defects when aligned to EUV-defined chemical guides. However, metal-oxide EUV resists (MORs), which provide high resolution, face challenges in converting their patterns into effective chemical guides for DSA integration.

This study presents a novel method using hydrogen silsesquioxane (HSQ), a negative tone resist, to create chemical patterns for integrating MORs with DSA. The process involves forming a sacrificial chromium pattern from HSQ, which is later replaced with a polyethylene oxide brush layer and a nonpolar polystyrene brush. These steps allow the successful assembly of polystyrene-block-poly(methyl methacrylate) BCPs, achieving 24 nm full-pitch resolution. This approach shows potential for producing sub-10 nm patterns by combining high-χ BCPs with MOR-based EUV lithography, advancing next-generation semiconductor fabrication.


DSA of BCPs is a promising nanofabrication technique that utilizes the phase separation properties of BCPs to create highly ordered nanoscale patterns with feature sizes below 10 nm. In DSA, BCPs self-organize into distinct microdomains, forming well-defined structures that can be guided using chemoepitaxy or graphoepitaxy. Chemoepitaxy involves chemically patterned surfaces that influence the alignment and orientation of BCP domains, while graphoepitaxy uses topographical features to achieve similar control. High-χ (chi) BCPs are often used to achieve finer pattern resolutions, and material optimizations such as selecting appropriate substrates and brush layers are crucial to improving pattern quality and reducing defects. DSA has been explored for various semiconductor applications, including the creation of dense line-space arrays, hole shrink patterns, and advanced memory devices, offering significant potential to enhance pattern fidelity, reduce defectivity, and lower manufacturing costs.

Sources:

High-resolution chemical patterns from negative tone resists for the integration of extreme ultraviolet patterns of metal-oxide resists with directed self-assembly of block copolymers | Journal of Vacuum Science & Technology B | AIP Publishing

https://www.spiedigitallibrary.org/conference-proceedings-of-spie/12956/3010817/Material-and-process-optimization-for-EUV-pattern-rectification-by-DSA/10.1117/12.3010817.full


https://journals.spiedigitallibrary.org/conference-proceedings-of-spie/12497/124970K/EUV-lithography-line-space-pattern-rectification-using-block-copolymer-directed/10.1117/12.2657990.full
https://www.mdpi.com/2073-4360/12/10/2432


https://www.spiedigitallibrary.org/conference-proceedings-of-spie/PC12054/PC1205402/Exploring-the-synergy-between-EUV-lithography-and-directed-self-assembly/10.1117/12.2622565.full
https://journals.aps.org/prb/abstract/10.1103/PhysRevB.101.085407

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