Three-dimensional rigorous simulation of mask-induced polarization

Wei, Xukang; Urbach, H. P.; Wachters, A. J. H.; Aksenov, Y.

doi:10.1117/12.597732

Cited by 4 publications

(2 citation statements)

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“…For rigorous 3D EMF (electro-magnetic field) analysis of mask diffraction an in-house Philips simulator "Cyclop" has been used [5][6]. On Figure 1 the scheme for the EMF analysis is presented.…”

Section: Partial Polarization Effect At Reticle Levelmentioning

confidence: 99%

Influence of mask induced polarization effects on a pattern printability

Aksenov

Dirksen

Wei

et al. 2005

Optical Microlithography XVIII

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Through ArF immersion lithography a road towards increased optical resolution at the 193nm wavelength has been opened. According to recently proposed roadmaps, ArF immersion lithography will be used for 65nm and 45nm technology nodes. Consequently, keeping the same 4x optical demagnification factor, the dimensions on mask scale down to wavelength values when entering these nodes. Moreover CD control becomes tighter and approaches values of 2-3nm. At such conditions, topography on mask, its type and materials cannot be ignored anymore while evaluating image formation either for design analysis or OPC adjustments. The objective of this paper is to analyze the influence of mask topography on imaging. The mask topography influences polarization state and diffraction efficiencies, which are determine further image formation. Therefore these parameters and their dependence on mask type, materials and pitches are of the major concern during the analyses. We analyze the process latitude and CD variations through pitch. The complete rigorous analysis shows improved process windows with the increase of feature aspect ratio and at the same time a large through pitch CD deviation compared to the conventional Kirchhoff diffraction model.

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Section: Partial Polarization Effect At Reticle Levelmentioning

confidence: 99%

Influence of mask induced polarization effects on a pattern printability

Aksenov

Dirksen

Wei

et al. 2005

Optical Microlithography XVIII

Self Cite

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“…On another note, Hyun et al [33] reformulated the boundary conditions in FEM and included the imaging model in their approach. Wei et al used the FEM to study 3D rigorous simulation of mask induced polarization [34].…”

Section: Finite Element Methods (Fem)mentioning

confidence: 99%

Electromagnetic ray tracing model for line structures and characterization of advanced alignment marks in photolithography

Tan¹

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Line structures are an essential part in integrated circuit (IC) fabrication. In photolithography, the electromagnetic scattering of line structures is one of the main factors that determine the advancement of the technology node. From the perspective of modeling, a theoretical model to physically understand the scattering phenomenon is necessary for a solid foundation in efficient Abstract _____________________________________________________________________________________________ _____________________________________________________________________________________________ iii ERT model, the electromagnetic field that causes a disturbance in the amplitude profile for the total solution was identified and explained in detail. The accuracy of the ERT model was also verified by comparing with the finite difference time domain (FDTD) solution. For a single polysilicon line structure with width of 1.66 λ (λ is the wavelength) on silicon substrate, the developed ERT model was able to demonstrate amplitude correlation coefficient (ACC) of 0.978 and the maximum amplitude difference, Δ|Ez| of as low as-0.067. The subwavelength line width of 0.4 λ was identified as the limit of the ERT model for the single polysilicon line structure. The study of alignment marks focuses on their performance to meet the stringent overlay requirement for advanced technology node process. The simulation results obtained from rigorous coupled wave analysis (RCWA) demonstrated that by incorporating small periodic structure into the conventional alignment mark, the reflected diffraction efficiency was improved at the respective order. The experimental works were performed for 90 nm and 0.11 µm processes. It is demonstrated that overlay as low as 9 nm was achieved when 5th order mark was used for the 90 nm technology node front-end-of-line (FEOL) process. Narrow marks for backend-end-of-line (BEOL) process also showed compatible results with the lowest overlay of 10 nm. _____________________________________________________________________________________________ v of this work. In addition, the experiments would not be possible without the technical support from ASM Lithography, Mr. Lim Ser Yong and Mr. Alex Chew. To all my peers in Chartered Special Project (SP) group, in particular Clark, Timonthy, Caroline, Jia Mei, Suey Li, Gek Soon and Alan, I thoroughly enjoyed the time that we had spent in the SP room. I think the feeling is mutual. Thank you for making my student days in Chartered a memorable one. I would also like to thank Jone for her generous help to proofread all the chapters in this thesis. Last but not least, I would like to thank my parents for their everlasting and unconditional support throughout my graduate studies. Their caring has motivated me to enjoy every second in my daily life, even during the most difficult times of my research work. Table of Contents _____________________________________________________________________________________________

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