Sub-10-nm patterning process using directed self-assembly with high χ block copolymers

Abstract

Abstract. The perpendicularly orientated lamellar structure of the self-organized diblock copolymer is an attractive template for sub-10-nm line-and-space pattern formation. We propose a method of evaluating the neutral layer (NL) whose performance has an important bearing on the perpendicular orientation of the lamellar structure. The random copolymer of methyl methacrylate and i-butyl POSS methacrylate (MAIBPOSS) has been investigated as an NL for a polymethylmethacrylate-b-polymethacrylethylPOSS (PMMA-b-PMAIBPOSS) lamellar structure. PMMA-b-PMAIBPOSS material has the potential to form sub-10 nm line-and-space pattern, in addition to high etch selectivity due to its POSS structure. Under the free surface, PMMA-b-PMAIBPOSS film on the random copolymer layer showed horizontal orientation. However, a half-pitch of a 7-nm finger pattern structure was observed by peeling off the horizontally oriented layer. The upper portion of the PMMA-b-PMAIBPOSS film was eliminated till proximity of the random copolymer layer by CF 4 gas etching. From the result, it was revealed that the PMMA-r-PMAIBPOSS works as an NL. It was confirmed that the contact angle analysis using an appropriate polymer is a suitable method for evaluation of the surface energy performance of the copolymer with the attribute of high segregation energy.

Nanopatterning via Solvent Vapor Annealing of Block Copolymer Thin Films

“…7,153−155 The International Technology Roadmap has specified a key metric for directed self-assembly: the defectivity of a nanopattern must be less than 0.01 cm −2 , which is orders of magnitude below the state-of-the-art. 7,20 Research to optimize the annealing of thin films of block copolymers is therefore critical. With respect to solvent vapor annealing, it has been reported that the rate of swelling, degree of swelling, annealing time, and deswelling rate all influence the resulting defect density.…”

“…For semiconductor device applications, control over and quantification of the resulting defect density of a nanopattern is critical. ,− The International Technology Roadmap has specified a key metric for directed self-assembly: the defectivity of a nanopattern must be less than 0.01 cm –2 , which is orders of magnitude below the state-of-the-art. , Research to optimize the annealing of thin films of block copolymers is therefore critical. With respect to solvent vapor annealing, it has been reported that the rate of swelling, degree of swelling, annealing time, and deswelling rate all influence the resulting defect density. ,,,,, In terms of quantifying the defect density of a nanopattern formed via the self-assembly of a block copolymer, a well-described and automated method that extracts statistically relevant data would be preferred.…”

“…Owing to the nature of the bottom-up processing, block copolymer self-assembly is able to generate large scale periodic features with sizes as small as 3 nm, at low cost. − Block copolymers themselves are relatively inexpensive materials and comprise a well-studied family of polymers with two or more homopolymer segments (blocks), connected via covalent bonds. , The feature size, spacing, and shapes of the resulting self-assembled nanostructures can be tuned by choosing block copolymers with varying chain lengths, molecular weights, and chemical composition. , After two decades of development, block copolymer self-assembly in thin films has been shown to be capable of generating patterns of interest to the semiconductor industry, such as ordered hexagonal dot arrays, square arrays, bends, jogs, circles, and T-junctions. ,− A few examples of the many nanopatterns accessible via block copolymer self-assembly are shown in Figure . These thin film block copolymer nanopatterns can then be transferred to a substrate surface via etching or deposition. − Fabrication of field effect transistors, − contact hole applications, − phase change memory, , and bit patterned media − using block copolymer self-assembly technology has been demonstrated.…”

Orientation Control in Thin Films of a High-χ Block Copolymer with a Surface Active Embedded Neutral Layer

“…This imbalance results in a preference of one block to wet the air interface, which results in formation of parallel orientations of lamella and either featureless surfaces or island/hole morphologies rather than the desired, uniformly thick perpendicular lamella needed for patterning (Figure 1). 39,40 Polystyrene-block-poly(2-vinylpyridine) (PS-b-P2VP) is a good representative of a high χ BCP demonstrating this behavior. PS and P2VP have a large difference in surface tension, γ, with γ PS = 27.9 mN/m and γ P2VP = 34.1 mN/m estimated at 200 °C, 41 and consequently, thin films on substrates treated with neutral brushes display lamellae with undesirable parallel orientations after thermal annealing.…”

Directed self-assembly of block copolymers for sub-10 nm fabrication

“…The χ value also affects the interfacial width between two domains. Higher χ usually results in a smaller interfacial width and decreases line-edge roughness [26,27]. Two broad types of high χ BCPs have been extensively explored: BCPs containing inorganic blocks and fully organic BCPs.…”