Vectorial effects in subwavelength mask imaging

Cheng, Wen‐Hao; Farnsworth, Jeff N.; Bloomstein, Theodore M.; Grenville, Andrew

doi:10.1117/12.632372

Cited by 9 publications

(10 citation statements)

References 2 publications

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“…This is consistent with the conclusion made in Ref. [1], where also shows that there is no clear correlation of the Depth of Focus (DoF) with DoP from a 1D structure. …”

Section: D Image Log Slope Vs 2d Polarizationsupporting

confidence: 92%

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Mask absorber material dependence of 2D OPC in ArF high NA lithography

Cheng

Farnsworth

2006

22nd European Mask and Lithography Conference

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Rigorous optical proximity correction (OPC) for 3D reticle effects is critical to the success of 193nm wavelength immersion lithography implementation. The impact of 2D and 3D mask polarization and shadowing effects to 2D imaging in ultra high Numerical Aperture (NA) low-k1 imaging is assessed by simulation. An end-to-end (ETE) dense line 2D feature of various embedded (attenuated) phase shift mask (ePSM) with various material of film stack is studied. Line-end pullback is shown correlated with mask shadowing under TE-polarized OAI. Polarized OAI phase calibrated thinner mask absorber provides less shadowing, better 2D imaging window, and enables further scaling of mask feature patterning.

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“…This is consistent with the conclusion made in Ref. [1], where also shows that there is no clear correlation of the Depth of Focus (DoF) with DoP from a 1D structure. …”

Section: D Image Log Slope Vs 2d Polarizationsupporting

confidence: 92%

“…High NA vectorial illumination and mask induced polarization imaging effects of 1-D feature has been studied rigorously across various mask type [1] for 193.3nm (ArF) immersion lithography. To reduce mask polarization effect for OPC simplification, alternative mask material has been proposed and studied at industry.…”

Section: Introductionmentioning

confidence: 99%

Mask absorber material dependence of 2D OPC in ArF high NA lithography

Cheng

Farnsworth

2006

22nd European Mask and Lithography Conference

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“…To evaluate the direct impact from mask defects, IPS is assumed to be 100% in the simulated illuminator. The convolution of illumination polarization impurity and mask defect would only lead to worse mask defect printability owing to the inherent nature of image contrast degradation due to the polarization impurity [2]. In Fig.…”

Section: Mask Defect and Its Proximity Printabilitymentioning

confidence: 98%

“…As the vectorial imaging effects increases significantly in high NA immersion lithography [1], the printability of mask defect and SRAF will depend on the composite effects of illumination vectors, Wood/Rayleigh resonance anomaly [1], mask material dependent 2-D feature proximity [2], optical proximity correction (OPC) features, mask topographic shadowing [2], effective mask glass trenching [3], and even pellicle membrane [1,4]. The rule of thumb for defect printability threshold band for conventional masks [5], will require thorough study to re-investigate the multi-parameter space in the high-NA imaging landscape.…”

Section: Introductionmentioning

confidence: 99%

Deep subwavelength mask assist features and mask errors printability in high NA lithography

et al. 2006

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As silicon processes scale toward the 45 nm node using conventional 0.25 magnification, widths of sub-resolution assist feature (SRAF) and printable defects on photomasks drop far below the ArF laser wavelength. Adoption of polarized illumination and higher numerical aperture (NA) could invalidate the scaling relations we used in the past to determine which small mask features or errors will print on wafers. Polarization interaction with small mask features may also plays a role in mask inspection. As mask features shrink below the wavelength, differences between the optical systems used for inspection and printing become more significant, and may affect the rules for disposition of inspection results. The data presented here combines experimental results from high NA imaging of sub-wavelength SRAF and defects, with rigorous calculation of their images based on vector diffraction. The printability of these deep subwavelength mask feature determines the requirements of optical model's rigorousness for SRAF design rule and also mask defect inspection & repair capabilities.

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“…method will induce a loss of high-spatial-frequency transmitted intensity, which is similar in form and in negative impact to a strong lens-apodization effect. 8,9 The fundamental problem with pellicle transmission as a function of angle is well understood, being simply a thinfilm optics interference effect. Figure 12 shows the issue for a typical thin organic 193-nm pellicle.…”

Section: Trapezoidal Filter Modelmentioning

confidence: 99%

Novel apodization and pellicle optical models for accurate optical proximity correction modeling at 45 and <inline-formula><math altimg="none" display="inline" overflow="scroll"><mrow><mn>32</mn><mspace width="0.3em" /><mi>nm</mi></mrow></math></inline-formula>

Zhang

Lucas

Adrichem³

et al. 2007

J. Micro/Nanolith. MEMS MOEMS

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An accurate optical model is the foundation of an accurate optical proximity correction ͑OPC͒ model, which has always been the key for successful implementation of model-based OPC. As critical dimension ͑CD͒ control requirements become severe at the 45-and 32-nm device generations, OPC model accuracy and hence optical model accuracy requirements become more stringent. In previous generations, certain optical effects could be safely ignored. For example, the transmission attenuation particularly at high spatial frequencies caused by lens apodization effects and organic pellicle films was ignored or not accurately modeled in conventional OPC simulators. These effects are now playing a more important role in OPC modeling as technology scales down. Our simulations indicate these effects can cause CD modeling errors of 5 nm or larger, at the 45-nm technology node and beyond. Therefore, they must be accurately modeled in OPC modeling. In our OPC modeling methodology, we propose two novel low-pass-filter models to capture the frequency-dependent transmission attenuation due to lens apodization and to pellicle films. These parameterized novel lowpass-filter models ensure that lens apodization and pellicle-film-induced transmission attenuation can be appropriately account for through regression during the experimental OPC model calibration stage in the case where no measured transmission data are available, thus enabling physics-centric OPC model building with considerably higher accuracy. We can then avoid overfitting the OPC model, which could cause instability in the OPC correction stage. The validity and efficiency of the proposed novel models are also verified using an industry-standard lithography simulator as well as an experimental OPC model calibration at the 45-nm technology node.

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Vectorial effects in subwavelength mask imaging

Cited by 9 publications

References 2 publications

Mask absorber material dependence of 2D OPC in ArF high NA lithography

Mask absorber material dependence of 2D OPC in ArF high NA lithography

Deep subwavelength mask assist features and mask errors printability in high NA lithography

Novel apodization and pellicle optical models for accurate optical proximity correction modeling at 45 and <inline-formula><math altimg="none" display="inline" overflow="scroll"><mrow><mn>32</mn><mspace width="0.3em" /><mi>nm</mi></mrow></math></inline-formula>

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