Single exposure EUV patterning of BEOL metal layers on the IMEC iN7 platform

Carballo, V.M. Blanco; Bekaert, Joost; Mao, Ming; Kotowska, Bogumila Kutrzeba; Larivière, S.; Ciofi, Ivan; Baert, Rogier; Kim, R. H.; Gallagher, Emily; Hendrickx, Eric; Tan, Ling Ee; Gillijns, Werner; Trivkovic, Darko; Leray, Philippe; Halder, Sandip; Gallagher, Michael; Lazzarino, Frédéric; Paolillo, Sara; Wan, Danny; Mallik, Arindam; Sherazi, Yasser; McIntyre, Greg; Dusa, Mircea V.; Rusu, P.; Hollink, Thijs; Fliervoet, Timon; Wittebrood, Friso

doi:10.1117/12.2258005

Cited by 8 publications

(8 citation statements)

References 5 publications

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“…The ability to directly print 2D features is a significant advantage of the SE EUV compared to multipatterning schemes and allows to simplify of the process flow by eliminating block patterning, at least at some metal layers 16 . Generally, T2T measurements are done using CDSEM, which measures multiple single T2T structures to exclude measurement noise and capture variations of the T2T structures 16 . Unique test sites with different T2T structures were created to test OCD capabilities, including the T2T variations and pitch.…”

Section: Resultsmentioning

confidence: 99%

“…16 Generally, T2T measurements are done using CDSEM, which measures multiple single T2T structures to exclude measurement noise and capture variations of the T2T structures. 16 Unique test sites with different T2T structures were created to test OCD capabilities, including the T2T variations and pitch. Structures with five different T2T dimensions (22 to 26 nm, step size = 1 nm) between S60 long islands were studied.…”

Section: Scatterometry and Ml: T2t CD Measurement Of 2d Featurementioning

confidence: 99%

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Investigating metal oxide resists for patterning 28-nm pitch structures using single exposure extreme ultraviolet: defectivity, electrical test, and voltage contrast study

Sarkar

Das

Carballo

et al. 2022

J. Micro/Nanopattern. Mats. Metro.

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Background: To keep up with the logic area scaling, back-end-of-line (BEOL) structures are reduced to smaller pitches, requiring faster and reliable metrology and defect detection solution.Aim: Metrology and detailed defect inspection at the early phases of process optimization.Approach: Single exposure (SE) 0.33NA extreme ultraviolet (EUV) lithography was used along with a bright field mask for patterning in a metal damascene process flow of BEOL structures. We also used a dual damascene process flow for voltage contrast (VC) metrology study.Results: Scatterometry technique, together with machine learning (ML), allowed us to have fast and accurate measurements of line-space (LS) and tip-to-tip (T2T) critical dimension (CD), and prediction of electrical performance. We demonstrated characterization results of stochastic defects across various test structures of 28-nm pitch devices. We used a large-area electron beam (e-beam) tool for high-speed large-area inspection which provided us with the quick feedback on defect signatures and scope for further root cause analysis. On a separate dual damascene integration flow, we used VC metrology to capture different failure modes in the patterning process of metal trenches with tight T2T and corresponding overlapping vias. Conclusions:We studied the impact of stochastic resist defects on electrical measurements of meander (MR) and fork-fork (FF) structures, and showed that large electrical test structures, built with a relatively simple patterning flow, can be used at the early stages of resist and patterning development, as the electrical failures are almost exclusively caused by the resist defects. In the dual damascene flow, we demonstrated that VC metrology is useful to determine the design rule parameters and capture different failure mechanisms.

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Section: Resultsmentioning

confidence: 99%

Section: Scatterometry and Ml: T2t CD Measurement Of 2d Featurementioning

confidence: 99%

Investigating metal oxide resists for patterning 28-nm pitch structures using single exposure extreme ultraviolet: defectivity, electrical test, and voltage contrast study

Sarkar

Das

Carballo

et al. 2022

J. Micro/Nanopattern. Mats. Metro.

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“…Extreme ultraviolet (EUV) lithography has emerged as a promising solution for the single exposure of sub 193i feature resolution limit and complex geometries, including curvilinear shapes. Imec studied an option to use single exposure EUV (SE EUV) to replace M1 as M2 for Self-Align-Double-Patterning+block and Self-Align-Quadruple-Patterning+block respectively [5] . It shows viability of SE EUV in iN7 node (foundry N5 equivalent) for Back-end-ofline (BEOL) layers which has design rules based on 42nm pitch for Metal 1 and 32nm pitch for subsequent Metal 2 and metal 3.…”

Section: Single Expose Euv On P32 Unidirectional Routing Emergence Of...mentioning

confidence: 99%

EUV single patterning validation of curvilinear routing

Treska¹,

Xu²,

Sherazi³

et al. 2023

Optical and EUV Nanolithography XXXVI

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Transistor pitch scaling drives the evolution of chip design. The late arrival of EUV lithography prompted the adoption of multiple patterning using 193i to continue transistor scaling. To facilitate multiple patterning integration schemes, the 2D design style was abandoned and unidirectional design style became dominant. As transistor scaling continues further, the demand on routing resources can exceed their supply leading to routing congestion [1] . Exploration on 1.5D or curvilinear routing to resolve higher Metal 2 usage was studied [2] . Nowadays, EUV lithography re-introduced single patterning for the most advanced nodes. At the same time, Multi Beam Mask Writer (MBMW) enables true curvilinear masks [3] . The use of curvilinear routing can potentially resolve routing congestion and more relax design rule check by combining EUV lithography and MBMW. This paper focuses on the challenges in optical proximity correction (OPC) on a design with curvilinear routing. Wafer data will be evaluated to assess quality. The target design is a D-flipflop using 2D and curvilinear features in a local interconnect layer to reduce the congestion. The base pitch of this design was scaled from 40nm to 32nm. The test design was then OPCed using Model Based OPC and Inverse Lithography Technique. Finally wafer data and process window analysis across the pitch range from different OPC variations will be revealed.

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“…Fortunately, alternatives to chemically amplified resists are being explored. Promising results have been obtained with new materials, such as metal-oxide resists, 9,10 which are based on radiation chemistries that are substantially different from typical chemical amplification. Metal-oxide imaging materials have two advantages over conventional organic chemically amplified resists.…”

Section: Limitations Imposed By Stochasticsmentioning

confidence: 99%

The potential of EUV lithography

Levinson¹

2019

35th European Mask and Lithography Conference (EMLC 2019)

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Lithographers are currently unable to generate quality patterning at tight pitches with values of k1 that are as low as have been achieved routinely using ArF immersion patterning, a situation that is largely due to the continuing pursuit of resists with low exposure doses. As a consequence, multiple patterning may be required to scale to a second node with EUV lithography, which reduces its cost-effectiveness, even if each individual exposure is done with a low exposure dose. Because of process control limitations, such multiple patterning may necessarily be triple or quadruple patterning, rather than double patterning. Processes with reduced line-edge roughness (LER) could be applied to front-end layers, increasing the value of EUV lithography. High-NA EUV lithography is in development, with a number of technical issues requiring solution, but with no apparent show-stoppers.

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Single exposure EUV patterning of BEOL metal layers on the IMEC iN7 platform

Cited by 8 publications

References 5 publications

Investigating metal oxide resists for patterning 28-nm pitch structures using single exposure extreme ultraviolet: defectivity, electrical test, and voltage contrast study

Investigating metal oxide resists for patterning 28-nm pitch structures using single exposure extreme ultraviolet: defectivity, electrical test, and voltage contrast study

EUV single patterning validation of curvilinear routing

The potential of EUV lithography

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