SRAM, NAND, DRAM contact hole patterning using block copolymer directed self-assembly guided by small topographical templates

Bao, Xinyu; Yi, He; Bencher, Christopher; Chang, Li-Wen; Dai, Huixiong; Chen, Yongmei; Chen, P.-T. Joseph; Wong, H.-S. Philip

doi:10.1109/iedm.2011.6131510

Cited by 33 publications

(19 citation statements)

References 8 publications

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“…Request permissions from Permissions@acm.org. techniques, block copolymer directed self-assembly (DSA) is considered as a promising technology for patterning contact holes and vias in 7 nm technology nodes [1,2,3,4]. Figure 1 shows an example of using DSA to pattern the contacts of a half adder.…”

Section: Introductionmentioning

confidence: 99%

Directed Self-Assembly (DSA) Template Pattern Verification

Xiao

Tian

et al. 2014

Proceedings of the 51st Annual Design Automation Conference

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Directed Self-Assembly (DSA) is a promising technique for contacts/vias patterning, where groups of contacts/vias are patterned by guiding templates. As the templates are patterned by traditional lithography, their shapes may vary due to the process variations, which will ultimately affect the contacts/vias even for the same type of template. Due to the complexity of the DSA process, rigorous process simulation is unacceptably slow for full chip verification. This paper formulate several critical problems in DSA verification, and proposes a design automation methodology that consists of a data preparation and a model learning stage. We present a novel DSA model with Point Correspondence and Segment Distance features for robust learning. Following the methodology, we propose an effective machine learning (ML) based method for DSA hotspot detection. The results of our initial experiments have already demonstrated the high-efficiency of our ML-based approach with over 85% detection accuracy. Compared to the minutes or even hours of simulation time in rigorous method, the methodology in this paper validates the research potential along this direction.

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Section: Introductionmentioning

confidence: 99%

Directed Self-Assembly (DSA) Template Pattern Verification

Xiao

Tian

et al. 2014

Proceedings of the 51st Annual Design Automation Conference

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“…Also, as the EUV technique has been continually delayed, when it really comes out, it will be most likely to adopt double patterning technique to handle the challenges in 7 nm technology node. Recently, block copolymer directed self-assembly (DSA) has been receiving much attention with high throughput and low cost [2]- [5]. In DSA process, uniformly sized dense patterns (e.g.…”

Section: Introductionmentioning

confidence: 99%

Contact layer decomposition to enable DSA with multi-patterning technique for standard cell based layout

Xiao

Lin

Wong

2016

2016 21st Asia and South Pacific Design Automation Conference (ASP-DAC)

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Multiple patterning lithography has been widely adopted for today's circuit manufacturing. However, increasing the number of masks will make the manufacturing process more expensive. More importantly, towards 7 nm technology node, the accumulated overlay in multiple patterning will cause unacceptable edge placement error (EPE). Recently, directed self-assembly (DSA) has been shown to be an effective lithography technology that can pattern contact/via/cuts with high throughput and low cost. DSA is currently aiming at 7 nm technology, where the guiding template generation needs either double patterning EUV or multiple patterning DUV process. By incorporating DSA into the multiple patterning process, it is possible to reduce the number of masks and achieve a cost effective solution. In this paper, we study the decomposition problem for contact layer in rowbased standard cell layout with DSA-MP complementary lithography. We explore several heuristic-based approaches, and propose an algorithm that decomposes a standard cell row optimally in polynomial-time. Our experiments show that our algorithm guarantees to find a minimum cost solution if one exists, while the heuristic cannot or only finds a sub-optimal solution. Our results show that the DSA-MP complementary approach is very promising for the future advanced nodes.

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“…(g) Lower hole C.The AveDev for all the DSA patterns is less than 2 nm, indicating a good position registration accuracy and repeatability. After Bao et al[6].…”

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confidence: 96%

Block copolymer directed self-assembly enables sublithographic patterning for device fabrication

Wong

Bencher

et al. 2012

Alternative Lithographic Technologies IV

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The use of block copolymer self-assembly for device fabrication in the semiconductor industry has been envisioned for over a decade. Early works by the groups of Hawker, Russell, and Nealey [1][2] have shown a high degree of dimensional control of the self-assembled features over large areas with high degree of ordering. The exquisite dimensional control at nanometer-scale feature sizes is one of the most attractive properties of block copolymer self-assembly. At the same time, device and circuit fabrication for the semiconductor industry requires accurate placement of desired features at irregular positions on the chip. The need to coax the self-assembled features into circuit layout friendly location is a roadblock for introducing self-assembly into semiconductor manufacturing. Directed self-assembly (DSA) and the use of topography to direct the self-assembly (graphoepitaxy) have shown great promise in solving the placement problem [3][4]. In this paper, we review recent progress in using block copolymer directed self-assembly for patterning sub-20 nm contact holes for practical circuits.Recognizing that typical circuit layouts do not require long range order, we adopt a lithography sub-division approach akin to double-patterning and spacer patterning. Guiding topographical templates with sizes of the order of the natural pitch of the block copolymer can effectively guide the placement of block copolymer features at arbitrary locations irrespective of the natural (often hexagonal for cylindrical domains) arrangements of the block copolymer [5] (Fig. 1). This is possible because the forces from the lateral confinement from sidewall of the small topographical template are strong. Using small topographical templates, contact hole patterns that are often used in circuit layouts can be placed at arbitrary location by first patterning a coarse guiding template using conventional lithography [5-6] (Fig. 2). This procedure is akin to double-patterning and spacer patterning where a coarse lithographic pattern is used to generate a higher resolution feature at a location determined by the coarse lithographic pattern. The size and registration of the features are determined by parameters of the template as well as the block copolymer itself. Preliminary analysis of the size and positional accuracy of small template DSA shows great promise [6] (Fig. 3). Downloaded From: http://proceedings.spiedigitallibrary.org/ on 07/02/2015 Terms of Use: http://spiedl.org/termsTo illustrate the use of this small template DSA approach, we use 193 nm immersion lithography to print the templates for 22-nm node SRAM cells reported by IBM [7]. The contact for the polysilicon-to-diffusion cross-over of the SRAM cell is implemented by a two-hole contact pattern (Fig. 2c) instead of an elliptical contact in the original design (Fig. 4). Well-formed contact hole patterns with good positional accuracy are obtained (Fig. 5) using only one lithography step followed by block copolymer DSA.Pattern transfer of the block copolymer soft mask into device ...

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SRAM, NAND, DRAM contact hole patterning using block copolymer directed self-assembly guided by small topographical templates

Cited by 33 publications

References 8 publications

Directed Self-Assembly (DSA) Template Pattern Verification

Directed Self-Assembly (DSA) Template Pattern Verification

Contact layer decomposition to enable DSA with multi-patterning technique for standard cell based layout

Block copolymer directed self-assembly enables sublithographic patterning for device fabrication

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