A comparison of the pattern transfer of line-space patterns from graphoepitaxial and chemoepitaxial block co-polymer directed self-assembly

Millward, Dan B.; Lugani, Gurpreet S.; Khurana, Ranjan; Light, Scott; Niroomand, Ardavan; Hustad, Phillip D.; Trefonas, Peter; Chang, Shih-Wei; Lee, Christopher N.; Quach, Dung

doi:10.1117/12.2045580

Cited by 7 publications

(5 citation statements)

References 8 publications

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“…As explained by Wang et al [7], a notable part of the structure in PS-b-PMMA structures with such small domain sizes still consists of a diffuse interface, where the structure is neither pure PS nor pure PMMA. This could explain the relatively large line-edge roughness of the structures, which is even larger after removal of the PMMA block [32]. The absence of defects proves that commensurable guiding patterns can be fabricated with t-SPL.…”

Section: Resultsmentioning

confidence: 91%

Thermal scanning probe lithography for the directed self-assembly of block copolymers

et al. 2017

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Thermal scanning probe lithography (t-SPL) is applied to the fabrication of chemical guiding patterns for directed self-assembly (DSA) of block copolymers (BCP). The two key steps of the overall process are the accurate patterning of a poly(phthalaldehyde) resist layer of only 3.5 nm thickness, and the subsequent oxygen-plasma functionalization of an underlying neutral poly(styrene-random-methyl methacrylate) brush layer. We demonstrate that this method allows one to obtain aligned line/space patterns of poly(styrene-block-methyl methacrylate) BCP of 18.5 and 11.7 nm half-pitch. Defect-free alignment has been demonstrated over areas of tens of square micrometres. The main advantages of t-SPL are the absence of proximity effects, which enables the realization of patterns with 10 nm resolution, and its compatibility with standard DSA methods. In the brush activation step by oxygen-plasma exposure, we observe swelling of the brush. This effect is discussed in terms of the chemical reactions occurring in the exposed areas. Our results show that t-SPL can be a suitable method for research activities in the field of DSA, in particular for low-pitch, high-χ BCP to achieve sub-10 nm line/space patterns.

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Section: Resultsmentioning

confidence: 91%

Thermal scanning probe lithography for the directed self-assembly of block copolymers

et al. 2017

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“…These techniques, referred to as directed self-assembly (DSA), provide powerful approaches to density multiplication using relatively simple spin-on processes. When combined with chemical − or topographic − patterns made with conventional lithography, DSA becomes an attractive candidate for future IC patterning, as evidenced by its position on the International Technology Roadmap for Semiconductors as an option for future patterning.…”

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confidence: 99%

“…Perpendicularly aligned lamellae form “fingerprint” patterns with alternating domains that resemble line/space patterns, while parallel lamella form layered structures referred to as islands or holes depending on film thickness and wetting preference at both the substrate and air interface (Figure ). Parallel cylinders can also form similar line/space patterns, − but lamellar BCPs are typically desired for line/space patterning as they provide advantages in pattern transfer and defectivity. ,, …”

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confidence: 99%

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

Zhang

Clark

et al. 2015

Nano Lett.

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Directed self-assembly (DSA) of block copolymers (BCPs) is an attractive advanced patterning technology being considered for future integrated circuit manufacturing. By controlling interfacial interactions, self-assembled microdomains in thin films of polystyrene-block-poly(methyl methacrylate), PS-b-PMMA, can be oriented perpendicular to surfaces to form line/space or hole patterns. However, its relatively weak Flory interaction parameter, χ, limits its capability to pattern sub-10 nm features. Many BCPs with higher interaction parameters are capable of forming smaller features, but these "high-χ" BCPs typically have an imbalance in surface energy between the respective blocks that make it difficult to achieve the required perpendicular orientation. To address this challenge, we devised a polymeric surface active additive mixed into the BCP solution, referred to as an embedded neutral layer (ENL), which segregates to the top of the BCP film during casting and annealing and balances the surface tensions at the top of the thin film. The additive comprises a second BCP with a "neutral block" designed to provide matched surface tensions with the respective polymers of the main BCP and a "surface anchoring block" with very low surface energy that drives the material to the air interface during spin-casting and annealing. The surface anchoring block allows the film to be annealed above the glass transition temperature of the two materials without intermixing of the two components. DSA was also demonstrated with this embedded neutral top layer formulation on a chemical patterned template using a single step coat and simple thermal annealing. This ENL technology holds promise to enable the use of high-χ BCPs in advanced patterning applications.

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“…[12, 16-20, 22, 23] Recently, a process to form desirable 1:1 line/space patterns was demonstrated using graphoepitaxy and parallel cylinder morphologies. [24] This process, shown in Figure 1, begins with patterning and etch trimming to form narrow guiding weirs of a hard mask material on a carbon floor. These weirs are then coated with a brush polymer, which forms a polymer layer selectively on the weirs.…”

Section: Introductionmentioning

confidence: 99%

Impact of materials selection on graphoepitaxial directed self-assembly for line-space patterning

Quach¹,

Ginzburg

Li³

et al. 2015

Alternative Lithographic Technologies VII

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Directed self-assembly (DSA) of block copolymers (BCPs) is a promising technology for advanced patterning at future technology nodes, but significant hurdles remain for commercial implementation. While chemoepitaxy processes employing poly(styrene-block-methyl methacrylate) (PS-PMMA) are most widely studied for DSA line/space patterning, graphoepitaxy processes using more strongly segregated "high-" block copolymers have recently shown a lot of promise, with lower defectivity and line-width roughness (LWR) than comparative chemoepitaxy processes. This paper reports on some of the design considerations for optimizing line/space patterning with these materials. We have found that brush and block copolymer selection are critical to achieve high quality DSA. For example, brush thickness must be optimized to achieve matching space critical dimensions, and brush surface energy impacts kinetics of assembly. The  parameter of the block copolymer should be optimized to balance LWR, kinetics of assembly, and process window. Glass transition temperature (T g ) of the blocks showed little impact on performance. Overall, parameters of both BCP and brush must be simultaneously optimized to achieve high quality DSA.

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A comparison of the pattern transfer of line-space patterns from graphoepitaxial and chemoepitaxial block co-polymer directed self-assembly

Cited by 7 publications

References 8 publications

Thermal scanning probe lithography for the directed self-assembly of block copolymers

Thermal scanning probe lithography for the directed self-assembly of block copolymers

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

Impact of materials selection on graphoepitaxial directed self-assembly for line-space patterning

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