Extend 0.33 NA extreme ultraviolet single patterning to pitch 28-nm metal design by low-n mask

Xu, Dongbo; Gillijns, Werner; Tan, Ling Ee; Río, David; Delorme, Max; Philipsen, Vicky; Kim, Ryoung-Han

doi:10.1117/1.jmm.21.4.043202

Cited by 6 publications

(12 citation statements)

References 27 publications

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“…140nm. 1 The further studies indicate that this phenomena is due to pronounced source-dependent mask 3D effects, and the phase offset among the diffraction orders results in the imaging pattern shifts. 10,11 Therefore, it is very interesting to know the best focus shifts behavior for the low-n attPSM at 0.55NA.…”

Section: Best Focus Shifts Through Pitchmentioning

confidence: 91%

“…Extreme ultraviolet lithography (EUVL) with a NA of 0.33 has been part of high-volume manufacturing (HVM) over the past few years, which promises the opportunity of EUV single patterning to print minimum pitch 28nm logic metal layer using an advanced low-n low-k absorber attenuated phase-shift mask (low-n attPSM) at the technology factor k 1 =0.34. 1 To continue the shrink of the transistor and enable the cost-effective manufacturing for next decade, a higher resolution lithography tool is needed. Therefore, the new high-NA EUVL with a NA of 0.55 is being developed at ASML.…”

Section: Introductionmentioning

confidence: 99%

“…1 is chosen to represent the relevant design of the logic metal layer, which had been used to investigate the patterning performance of alternate mask stacks at 0.33NA EUVL. 1,7 Figure 2 presents the linear pitch scaling of the imec N3 random logic metal design clips, which is scaled from pitch 28nm down to pitch 18nm, both horizontal and vertical design orientations are included. The clips will be placed on the high-NA masks, and the relevant wafer data will be used to study the feasibility of logic metal scaling with 0.55NA EUV single patterning.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Feasibility of logic metal scaling with 0.55NA EUV single patterning

Xu¹,

Tan

Philipsen³

et al. 2023

Optical and EUV Nanolithography XXXVI

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By adopting the new design of the optics within the scanner, high-NA (0.55NA) EUV lithography enables higher resolution, which will push the EUV single patterning down to pitch 16nm (k1=0.34, the same k1 value as pitch 28nm for 0.33NA EUV single patterning). Therefore, 0.55NA EUVL is projected to print the most critical features of 2nm node (and beyond) logic chips with less patterning steps than 0.33NA EUVL, and is highly expected by the industry. Besides, novel low-n low-k absorber attenuated phase shift masks (low-n attPSMs) are commercially available recently, which have shown substantial imaging, as well as patterning performance improvements both in simulations and experiments. Thus, in this paper, we evaluate the feasibility and limits of logic metal scaling with 0.55NA EUV single pattering using source mask optimization tool, both binary and low-n attPSMs are used to pattern an imec N3 (pitch 28nm, foundry N2 equivalent) random logic metal design and the linear scaled versions (down to pitch 18nm). The impact of design orientations (horizontal vs. vertical) and mask tones (dark field vs. bright field) on patterning fidelity and overall process window is evaluated.

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Section: Best Focus Shifts Through Pitchmentioning

confidence: 91%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Feasibility of logic metal scaling with 0.55NA EUV single patterning

Xu¹,

Tan

Philipsen³

et al. 2023

Optical and EUV Nanolithography XXXVI

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“…In the past years, masks with low-n absorber have been evaluated for their dose and contrast benefit. [3][4][5][6] Figure 1(a) plots the experimental exposure latitude through pitch for equal lines/spaces (LS) at NA0.33 of a low-n mask versus a Ta-based reference mask with their respective optimized illumination pupil for pitch 28 nm LS. The exposure dose at each pitch was selected to print equal LS on mask to equal LS on wafer, as shown in Fig.…”

Section: Novel Absorber Maskmentioning

confidence: 99%

Mask innovations on the eve of high NA EUV lithography

Philipsen,

Frommhold,

Thakare

et al. 2024

Jpn. J. Appl. Phys.

Self Cite

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We are on the eve of the next big step in lithography technology with the introduction of High numerical aperture EUV. The change from NA 0.33 to 0.55 in EUV lithography is an increase of 67%, which is the largest jump in the last decades, and puts tight requirements on focus and edge placement. Moreover, the lithography system has changed from fully isomorphic, i.e., same demagnification in all directions, to an anamorphic system, i.e., the demagnification in scan direction has doubled with respect to the slit direction. At imec we are fostering the ecosystem surrounding the lithography tool. In this paper we focus on the imaging and mask innovations supporting the EUV ecosystem, which are categorized into four areas: novel absorber masks, stitching, mask variability, and innovative imaging solutions. The current drivers of IC manufacturers implementing (High NA) EUVL are reduction of the EUV exposure dose and decrease in wafer stochastics. We discuss how these four areas have the potential to deliver in EUVL an increase in productivity, an improvement in the process window and a reduction in stochasticity at wafer level.

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“…Therefore, the SMO process should include through-pitch L/S and T2T structures as input patterns. We conducted a throughpitch SMO while imposing a higher weighting on the minimum metal pitch since it is the most critical pattern in logic metal layer patterning and requires a sufficient level of contrast or NILS [7][8][9] . This approach is demonstrated in Figure 2.1, where the SMO results show four different cases optimized for different patterns.…”

Section: Optimization Of Through-pitch Smomentioning

confidence: 99%

Computational evaluation of critical logical metal layers of pitch 20-24nm and the aberration sensitivity in high NA EUV single patterning

Gao

Chen

Zimmermann

2023

DTCO and Computational Patterning II

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As chip manufacturers seek to reduce the pitch of metal layers, there is growing interest in replacing the multiple patterning process of 0.33NA EUV with a single patterning of high NA (0.55NA) EUV. However, to resolve a logic metal layout with a minimum pitch of 20-24nm, careful use of resolution enhancement techniques (RETs) and SMO (source mask optimization) is required in high NA EUV. Logic metal patterns are complex and have various feature designs, making it essential to ensure sufficient patterning performance across all pitches and for variations of tip-to-tip (T2T) structures with a tight size. In this study, we simulated and evaluated patterning on a typical logic metal layout representing 1.4nm to 1nm technology nodes. Our study demonstrates that compromised criteria are necessary to ensure the NILS (normalized image log-slope) level of the minimum pitch and the overlap critical dimension (CD) process window (PW). In optical proximity correction (OPC), sub-resolution assistant features (SRAF) help to improve the process window of isolated and semi-iso line-and-space (L/S) patterns. However, we found that the limiting patterns are the tight T2T structures. Aberration sensitivity showed a linear response that is more pronounced to pattern placement errors (PPE) than to CDs. The coma series aberration showed the highest sensitivity to PPE and CD. Overall, our study demonstrates that RETs, rigorous SMO solutions, and a minimum T2T size are required to achieve the replacement of 0.33NA EUV multi-patterning with a 0.55NA EUV single patterning (SP) for logic metal layers with minimum pitches of 20-24nm.

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Extend 0.33 NA extreme ultraviolet single patterning to pitch 28-nm metal design by low-n mask

Cited by 6 publications

References 27 publications

Feasibility of logic metal scaling with 0.55NA EUV single patterning

Feasibility of logic metal scaling with 0.55NA EUV single patterning

Mask innovations on the eve of high NA EUV lithography

Computational evaluation of critical logical metal layers of pitch 20-24nm and the aberration sensitivity in high NA EUV single patterning

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