Properties of EUVL masks as a function of capping layer and absorber stack structures

Seo, Hwan-Seok; Park, Jin‐Hong; Lee, Seungyoon; Park, Joo-On; Kim, Hun; Kim, Seong-Sue; Cho, Han-Ku

doi:10.1117/12.713301

Cited by 12 publications

(7 citation statements)

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“…The usage of the intermixing layers in simulation seems to be unavoidable because otherwise peak reflectivity and FWHM of the spectrum are largely overestimated. The actual presence of the MoSi 2 intermixing layers was demonstrated in [1] by means of transmission electron spectroscopy (XTEM) showing the intermixing layers with thickness of 0.6 nm on Mo top and 1.7 nm on Si top with the full ML period of 6.95 nm and Mo/Si ratio of 0.4. Notice that in our simulation we have kept the ratios between the layers thickness close to these experimental values, while the total ML period was 1.5% increased in order to match the centroid wavelength.…”

Section: Multilayer Centroid Wavelength Optimizationmentioning

confidence: 99%

Mask aspects of EUVL imaging at 27nm node and below

Davydova

Setten

Han³

et al. 2011

SPIE Proceedings

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EUVL requires the use of reflective optics including a reflective mask. The mask consists of an absorber layer pattern on top of a reflecting multilayer, tuned for 13.53 nm. The EUVL mask is a complex optical element with many parameters contributing the final wafer image quality. Specifically, the oblique incidence of light, in combination with the small ratio of wavelength to mask topography, causes a number of effects which are unique to EUV, such as an HV CD offset. These so-called shadowing effects can be corrected by means of OPC, but also need to be considered in the mask stack design. In this paper we will present an overview of the mask contributors to imaging performance at the 27 nm node and below, such as CD uniformity, multilayer and absorber stack composition, thickness and reflectivity. We will consider basic OPC and resulting MEEF and contrast. These parameters will be reviewed in the context of real-life scanner parameters both for the NXE:3100 and NXE:3300 system configurations. The predictions will be compared to exposure results on NXE:3100 tools, with NA=0.25 for different masks. Using this comparison we will extrapolate the predictions to NXE:3300, with NA=0.33. Based on the lithographic investigation, expected requirements for EUV mask parameters will be proposed for 22 nm node EUV lithography, to provide guidance for mask manufacturers to support the introduction of EUV High Volume Manufacturing.

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Section: Multilayer Centroid Wavelength Optimizationmentioning

confidence: 99%

Mask aspects of EUVL imaging at 27nm node and below

Davydova

Setten

Han³

et al. 2011

SPIE Proceedings

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“…intermixing layers found in the analysis of ML cross-section [4]. The difference between the two stacks is a higher γ=Mo/(Mo+Si) for the stack A manifesting itself with a lower peak reflectivity, a broader FWHM and a lower centroid wavelength.…”

Section: Layer Thickness [Nm]mentioning

confidence: 97%

EUVL mask performance and optimization

et al. 2012

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d Toppan Photomasks inc., 131 Old Settlers Boulevard, Round Rock, TX 78664 USA EUV lithography requires an exposure system with complex reflective optics and an equally complex EUV dedicated reflective mask. The required high level of reflectivity is obtained by using multilayers. The multilayer of the system optics and the mask are tuned to each other. The mask is equipped with an additional patterned absorber layer.The EUV mask is an optical element with many parameters that contribute to the final image and overlay quality on the wafer and the productivity of the system. Several of these parameters can be tuned for optimal overlay, imaging and productivity results. This should be done with care because of possible interaction between parameters.We will present an overview of the EUV mask contributors to the imaging, overlay and productivity performance for the 27 nm node and below, such as multilayer and absorber stack composition, reflectivity and reflectivity uniformity. These parameters will be reviewed in the context of real-life scanner parameters for the ASML NXE:3100 and NXE:3300 system configurations. The predictions will be compared to actual exposure results on NXE:3100 systems (NA=0.25) for various masks and extrapolated to the NXE:3300 (NA=0.33).In particular, we will present extensive multilayer and absorber actinic spectral reflectance measurements of a state-ofthe art EUV mask over a range of incidence angles corresponding to an NA of 0.33 at multiple positions within the image field. The ML measurements allow calibrating ML stack for imaging simulations. It allows also the estimation of mask-induced apodization effects having impact on overlay.In general, the reflectivity measurements will give detailed variations over the image field of mask parameters such as ML centroid wavelength and absorber reflectivity which contribute to CD uniformity. Such a relation will be established by means of rigorous full stack imaging simulations taking into account optical properties of the coming NXE:3300 system.Based on this investigation we will propose optimal EUV mask parameters for the 22 nm node EUV lithography and below, to provide guidance for mask manufacturers to support the introduction of EUV High Volume Manufacturing.

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“…Also the simulated curve does not match to the experimental one. Based on literature we know that intermixing between the Si and Mo layers will happen [2,6]. Table 2 presents the details of a ML with intermixing from [6].…”

Section: Starting Pointmentioning

confidence: 99%

“…Commonly in literature [2][3][4][5] we find the ML stack definition as given in Table 1. The optical constants n&k are wavelength dependent and all simulations through wavelength in this paper use the n&k values through wavelength.…”

Section: Starting Pointmentioning

confidence: 99%

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Actinic characterization and modeling of the EUV mask stack

Philipsen¹,

Hendrickx

Jonckheere

et al. 2013

SPIE Proceedings

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This paper presents a detailed mask stack modeling based on experimental actinic characterization of the EUV mask stack. A dedicated mask has been fabricated with line/space gratings down to 40nm half-pitch (at mask level, i.e., 10nm at wafer). Using the Advanced Light Source facility at LBNL extensive reflectometry and diffractometry have been performed. The experimental reflectivity results through incidence angle and through EUV wavelength enable us to model both the multilayer definition, as well as the absorber definition in the simulator. The effective performance of the calibrated mask stack in the simulator is validated against the experimental diffractometry results through incidence angle. The presented experimental mask stack characterization and modeling allows a better definition of the mask stack in the simulation tools to enhance their predictive and precompensation power.

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Properties of EUVL masks as a function of capping layer and absorber stack structures

Cited by 12 publications

References 0 publications

Mask aspects of EUVL imaging at 27nm node and below

Mask aspects of EUVL imaging at 27nm node and below

EUVL mask performance and optimization

Actinic characterization and modeling of the EUV mask stack

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