Healing LER using directed self assembly: treatment of EUVL resists with aqueous solutions of block copolymers

Chuang, Ya-Mi; Cheng, Han-Hao; Jack, Kevin S.; Whittaker, Andrew K.; Blakey, Idriss

doi:10.1117/12.2012488

Cited by 3 publications

(3 citation statements)

References 47 publications

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“…This emphasizes the potential of EUV lithography as the next leading technology for semiconductor device manufacturing by obeying Moore's law. To expand the application of EUV lithography, new process techniques were proposed, such as the combination of EUV lithography and directed self-assembly [1][2][3][4] and negative tone development (NTD) [3][4][5][6][7][8] .…”

Section: Introductionmentioning

confidence: 99%

Evaluations of negative tone development resist and process for EUV lithography

Takahashi¹,

Fujitani²,

Itani³

2014

SPIE Proceedings

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Resists, underlayers, and new rinse processes were evaluated for negative tone development (NTD) using extreme ultraviolet (EUV) lithography. The most recently developed resists show resolution and sensitivity improvements. High remaining-film thickness was also achieved for better etching resistance. The underlayers smoothed the line width roughness (LWR) and prevented pattern collapse. In addition, the proposed NTD-compatible rinse process further assisted to prevent pattern collapse. The best NTD performance at EIDEC till date was achieved: 22 nm line and space (L/S) resolution, 5.4 nm LWR, and 16.8 mJ/cm 2 sensitivity with annular illumination for a small-field exposure tool (SFET). Furthermore, an ultimate resolution of 17 nm L/S was achieved with x-dipole illumination of SFET. The lithographic performance of the best NTD resist is comparable to the typical positive tone development resist.

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Section: Introductionmentioning

confidence: 99%

Evaluations of negative tone development resist and process for EUV lithography

Takahashi¹,

Fujitani²,

Itani³

2014

SPIE Proceedings

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“…Healing of LER following development is another approach that has led to significant improvements in LER. [27,28] On the other hand, directed self assembly (DSA) of block copolymers is a technique that has demonstrated significant promise for achieving high resolution. DSA is a technique that brings together lithography (top-down) to fabricate patterns that guide the self assembly of diblock copolymers (bottom-up).…”

Section: Introductionmentioning

confidence: 99%

Extending the scope of poly(styrene)-block-poly(methyl methacrylate) for directed self-assembly

et al. 2014

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Directed self-assembly (DSA) is a promising technique for extending conventional lithographic techniques by being able to print features with critical dimensions under 10 nm. The most widely studied block copolymer system is polystyreneblock-polymethyl methacrylate (PS-b-PMMA). The system is well understood in terms of its synthesis, properties and performance in DSA. However, PS-b-PMMA also has a number of limitations that impact on its performance and hence scope of application. The primary limitation is the low Flory-Huggins polymer-polymer interaction parameter (χ), which limits the size of features that can be printed by DSA. Another issue with block copolymers in general is that specific molecular weights need to be synthesized to achieve desired morphologies and feature sizes. We are exploring blending ionic liquid additiveswithPS-b-PMMAto increase the χ parameter. This allows smaller feature sizes to be accessed by PS-b-PMMA. Depending on the amount of additive it is also possible to tune the domain size and the morphology of the systems. These findings may expand the scope of PS-b-PMMA for DSA.

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“…Use of directed self-assembly (DSA) of block copolymer is another approach to healing LER [11,12]. It has been shown that the highly ordered patterns of immiscible blocks formed by DSA depending on the relative volume fraction of each block, the total molecular weight, and the degree of immiscibility, have smaller LER than the lithographic features that were used to guide them [43].…”

Section: Figure-113mentioning

confidence: 99%

Understanding and controlling the structure of thin polymer films used in photolithography

Alam¹

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Line edge roughness (LER) is one of the major impediments to the semiconductor industry achieving the desired device performance and satisfying the goals set by International Technology Roadmap for Semiconductor (ITRS). LER is defined as any sort of unwanted roughness in semiconductor features, and among many other factors, structural heterogeneity of the photoresist materials is one of the sources of LER in photolithographic devices. This gives the motivation to study a new class of copolymer named 'gradient copolymer', which is unique in terms of the copolymer chain structure. The copolymer composition of gradient copolymers changes from one end of the chain to the other gradually, while the copolymer composition is on average constant along the chains for conventional statistical copolymers. In contrast, block copolymers show an abrupt switch in the polymer composition. In this study, statistical, block and gradient copolymers have been synthesized for two different monomer pairs (styreneacrylonitrile and hydroxystyrene t-butyl acrylate) using reversible addition-fragmentation chain transfer (RAFT) and conventional radical polymerization (CvRP) method, and their surface properties extensively studied.The kinetics of copolymerization of styrene (St) and acrylonitrile (AN) by RAFT method was studied in detail. Reactivity ratios of St and AN were determined for nine different feed compositions for RAFT, and the effect of solvent on reactivity ratios was discussed based on the bootstrap model. Batch polymerization of styrene (St) and acrylonitrile (AN) yielded statistical and spontaneous gradient copolymers depending on the monomer feed ratio, and the chain structures were confirmed from the change in the copolymer composition. St-and AN-centered triad distributions were determined using quantitative 13 C NMR. Using the continuous feeding approach, forced gradient St-AN copolymers were prepared, and St-block-AN copolymers synthesized by the chain extension method. Statistical, gradient and block copolymers have also been synthesized for the acetoxystyrenet-butyl acrylate monomer system. The statistical and gradient structures were confirmed from the change in the composition since this pair does not provide any well resolved peaks for different triad sequences in 13 C NMR. Hydroxystyrenet-butyl acrylate (HOST-tBA) copolymers were prepared by selective hydrolysis of 4-acetoxystyrenet-butyl acrylate (AOST-tBA) copolymers.The properties of the both copolymer systems were found to be strongly dependent on the copolymer structure. A unique broad glass transition was observed for the gradient copolymers, which is different from behaviour of the statistical and block copolymers. Surface properties of St-AN statistical, gradient and block copolymer thin films were found to be very different due to the

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Healing LER using directed self assembly: treatment of EUVL resists with aqueous solutions of block copolymers

Cited by 3 publications

References 47 publications

Evaluations of negative tone development resist and process for EUV lithography

Evaluations of negative tone development resist and process for EUV lithography

Extending the scope of poly(styrene)-block-poly(methyl methacrylate) for directed self-assembly

Understanding and controlling the structure of thin polymer films used in photolithography

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