Characterization of EUV image fading induced by overlay corrections using pattern shift response metrology

Schmidt, Daniel; Cornell, Roger; Kling, Michael E.; Gabor, Allen H.; Ausschnitt, Christopher P.

doi:10.1117/12.2536690

Cited by 6 publications

(5 citation statements)

References 1 publication

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“…For the implementation of EUVL in HVM, it is essential to find pellicle materials with small thermal and mechanical damage and a long lifetime. 27) In this study, the maximum thermal stress from EUV exposure was calculated and compared for various pellicle structures and materials. To predict the pellicle lifetime, the mechanical stability of the pellicles was evaluated through a comparative analysis of the time at which the pellicle begins to crack due to thermal stress.…”

Section: Discussionmentioning

confidence: 99%

“…Because the thickness is very low compared to the pellicle area, conduction can also be neglected in the thermal equation. 26,27) Because heat radiation was emitted from the front and back sides of the film, s is twice the total film area. The temperature of the pellicle surface was mainly cooled by the radiation process.…”

Section: Checking the Model's Consistency (Theory And Experiment)mentioning

confidence: 99%

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Thermomechanical stability evaluation of various pellicle structures with contaminant particles

Ban

Kang

Choi

et al. 2021

Jpn. J. Appl. Phys.

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Extreme ultraviolet lithography in high-volume manufacturing requires a longer pellicle lifetime; however, the thermal deformation of pellicles due to repeated exposure can shorten the pellicle lifetime. Thermal stress is used as an indicator in most studies to predict the pellicle lifetime, but because the material can break under low thermal stress depending on the mechanical properties, evaluation of thermomechanical stability including thermal stress and mechanical durability is required. In this study, the thermal stress and mechanical stability of pellicles were evaluated through a comparative analysis of crack occurrence points resulting from thermal deformation for various pellicle structures and contaminant particles. The results show that the thermal stress was lower and the crack time was relatively longer for the metal silicide-based material compared with other pellicle structures. Moreover, it was found that the presence of contaminant particles could be the main cause of pellicle breakage.

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Section: Discussionmentioning

confidence: 99%

Section: Checking the Model's Consistency (Theory And Experiment)mentioning

confidence: 99%

Thermomechanical stability evaluation of various pellicle structures with contaminant particles

Ban

Kang

Choi

et al. 2021

Jpn. J. Appl. Phys.

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“…As illustrated in Figure 5, for vertical lines and spaces, the primary issue is image fading, whereby the images from each illumination pole are shifted relative to one another leading to a loss of contrast [11]. This shift arises from the propagation distance of the multilayer reflection and absorber transmission, which laterally shifts the reflection depending on illumination angle.…”

Section: Rigorous Simulationsmentioning

confidence: 99%

Understanding and measuring EUV mask 3D effects

Sherwin,

Hettermann,

Houser

et al. 2024

Optical and EUV Nanolithography XXXVII

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EUV lithography is rapidly being pushed to its resolution limit, where tradeoffs are heightened between resolution, throughput, and stochastics. Mitigation strategies include attenuated phase shift masks (aPSMs) and thinner high-k absorbers. Furthermore, multilayer bandwidth and phase shift may need to be reassessed. All these improvements relate to mask 3D effects (M3D), arising from several causes: First, phase shift vs pitch, which sets the aPSM target phase shift around 1.2pi instead of pi. Second, absorber thickness effects which directly relate to the promise of high-k absorbers. And third, multilayer effects like bandwidth and phase vs angle. In this manuscript we quantify these effects in simulation for different EUV scanner generations (0.33 and 0.55 NA). Moreover, we demonstrate the measurement of these effects with the EUV Tech ENK (EUV n/k tool) using actinic scatterometry. The complexity of M3D suggests that new metrics of multilayer and absorber performance beyond reflectivity will need to be considered. Actinic scatterometry provides a promising route to measuring M3D due to its sensitivity to wavelength, angle, and feature size.

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“…This unique design depicted in Figure 5 can be exposed either as a full field, top half-field or bottom-half field. Overlay marks were designed such that two subsequent but translated exposures complete the resist-to-resist metrology mark, which allows the study of overlay and other phenomena with minimal mask, alignment, and other unintentional contributions 5,6 . Only one of the two half-fields have been used for this set-get experiment.…”

Section: Simulation Calibrationmentioning

confidence: 99%

Impact of high-NA half-field to full-field overlay performance by Monte Carlo simulations

Lallement¹,

Schmidt

Johnson

et al. 2023

Optical and EUV Nanolithography XXXVI

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In an earlier publication, we evaluated simulation methods to explore overlay performance implications when a highNumerical Aperture (high-NA) Extreme Ultra Violet (EUV) exposure is mixed and matched with a 0.33NA EUV full field exposure. The present contribution goes beyond the method description and aims to quantify the overlay performance impact in such a mix and match case, giving insight into the influence of different sets of overlay corrections. To this aim, the Mont Carlo engine has been updated to accommodate overlay corrections with up to 57 parameters. Since high-NA EUV is not yet available, typical overlay correction terms from IBM’s 0.33NA EUV tool have been used to approximate a realistic image placement error fingerprint for our simulations. As a result, we demonstrate the benefit of various overlay correction sets, and the detrimental effect when using different masks for top and bottom half fields. Such information can also help to infer design layout placement decisions to avoid hot spot regions.

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Characterization of EUV image fading induced by overlay corrections using pattern shift response metrology

Cited by 6 publications

References 1 publication

Thermomechanical stability evaluation of various pellicle structures with contaminant particles

Thermomechanical stability evaluation of various pellicle structures with contaminant particles

Understanding and measuring EUV mask 3D effects

Impact of high-NA half-field to full-field overlay performance by Monte Carlo simulations

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