International Consensus Statement on Rhinology and Allergy: Rhinosinusitis

Background: The 5 years since the publication of the first International Consensus Statement on Allergy and Rhinology: Rhinosinusitis (ICAR‐RS) has witnessed foundational progress in our understanding and treatment of rhinologic disease. These advances are reflected within the more than 40 new topics covered within the ICAR‐RS‐2021 as well as updates to the original 140 topics. This executive summary consolidates the evidence‐based findings of the document. Methods: ICAR‐RS presents over 180 topics in the forms of evidence‐based reviews with recommendations (EBRRs), evidence‐based reviews, and literature reviews. The highest grade structured recommendations of the EBRR sections are summarized in this executive summary. Results: ICAR‐RS‐2021 covers 22 topics regarding the medical management of RS, which are grade A/B and are presented in the executive summary. Additionally, 4 topics regarding the surgical management of RS are grade A/B and are presented in the executive summary. Finally, a comprehensive evidence‐based management algorithm is provided. Conclusion: This ICAR‐RS‐2021 executive summary provides a compilation of the evidence‐based recommendations for medical and surgical treatment of the most common forms of RS

Influence of visco-elasticity of low-k dielectrics on thermo-mechanical behavior of dual damascene process

\u3cp\u3eFor backend processes, thermo-mechanical failure is one of the major failure modes. A representative metal structure in a Cu/low-k dual damascene process is examined, considering the major thermal loads and process steps through combined finite element simulation with experiments. Firstly, the low-k material, in our case the polymeric material SiLK (trade name of the Dow Chemical Company) is characterized and modeled to provide a reliable material model and data for the simulations. Characterization measurements (nano-indentation-creep test) are carried out on a polymer film deposited on a substrate. Here a quasi-elastic approach is used to account for the substrate influence and the time dependency acting at the same time. Elastic indentation curves are simulated with a varying modulus of the film within an expected interval. The coefficients for a Maxwell relaxation model are calculated, and verified through FEM simulations. Furthermore results of temperature dependency and influence on the modulus are examined and the WLF coefficients are calculated providing time and temperature dependent material parameters for the process simulations. The main dual damascene process steps are simulated using the obtained material model. Stresses are examined at different critical locations. Furthermore an initial defect is placed at a low-k-oxide interface, where energy release rates are determined. Our results show that Cu/low-k structures exhibit significantly different reliability characteristics than their aluminum predecessors, which are more critical from several design aspects. This not only makes the stress management in the stacks more difficult, but also strongly impacts packaging.\u3c/p\u3

The effect of material properties and initial defects on the thermo-mechanical behavior of a dual damascene module

\u3cp\u3eFor backend processes, thermo-mechanical failure is one of the major failure modes. A representative metal structure in a Cu/low-k dual damascene process is examined considering the major thermal loads and process steps through combined finite element simulation with experiments. Firstly the low-k material, in our case the polymeric material SiLK (trade name of the DOW Chemical Company), is characterized and modeled to provide a reliable material model and data for the simulations. The coefficients for a Maxwell relaxation model are calculated, temperature dependency and its influence on the modulus are examined and the WLF coefficients are calculated providing time and temperature dependent material parameters for the process simulations. The main dual damascene process steps are simulated using the obtained material model. Stresses are examined at different critical locations. Furthermore an initial defect is placed at a low-k-oxide interface, where energy release rates are determined. Our results show that Cu/low-k structures exhibit significantly different reliability characteristics than their aluminum predecessors, are more critical from several design aspects. This not only makes the stress management in the stacks more difficult, but also strongly impact packaging.\u3c/p\u3

Mechanical characterization of SiLK by nanoindentation and substrate curvature techniques

\u3cp\u3eAdvanced micro mechanical characterization methods provide material properties of thin films for modelling thermo mechanical behavior of thin films for microelectronic applications. Here we focus on the local measurement method of nanoindentation for finding visco-elastic properties, and a global method of substrate curvature testing that provides linear elastic properties. Our specimen SiLK, Dow Chemicals, is a thin polymer film with a thickness in 400nm and 8micron, deposited on Si substrate. Our results show temperature dependent linear elastic and linear visco-elastic material properties for thin film materials.\u3c/p\u3

Investigation on thermal properties of crosslinked epoxy resin by MD simulation

Behavior of epoxy resin is critical for performanceand reliability of electronic packages. The ability topredict properties of cross linked epoxy resin prior tolaboratory synthesis will facilitate the materials design. Theoretical studies in this field face a big challenge because there is no conventional way to build atomistic models of specific polymers, which form a network. Molecular dynamics (MD) is a potentially powerful method that can simulate the materials at atomic scale and it can be used to describe the performance and properties of a wide range of systems. In the present work, the properties of the cross-linked epoxy resin compound were predicted by MD simulations. Periodic amorphous structures of the cross-linked epoxy resincompound were simulated at various temperatures. Thecorrelation of the glass transition temperature (Tg) and properties of the cross-linked epoxy resin compoundwere investigated. The results show that Tg can beestimated by the plot of densities and non-bond energyat different temperatures. The Tg predicted was inagreement with the experimental data, which showsthat MD simulation is an effective tool to estimate theproperties of crosslinked epoxy resin

Mechanical characterization and modeling of low-dielectric-constant SiLK films using nano-indentation:Time- and temperature-effects

\u3cp\u3eSiLK [1] semiconductor dielectric is a polymeric material developed for use as a thin film dielectric in the interconnect structure of high density integrated circuits. Among others, its thermo-mechanical properties play a dominant role for the integrity and reliability of the interconnect, during processing, testing and use. Being a polymer, SiLK films may show viscoelastic (time-dependent) behavior. In this paper, we use nano-indentation experiments to determine the viscoelastic properties of a thin SiLK film on a silicon substrate as a function of temperature within the range 25-100°C. Also, the effect of the degree of curing of the films on the viscoelastic properties is studied. The experiments indeed show that the SiLK film responds in a viscoelastic way. The viscoelastic behavior can be described by a linear viscoelastic generalized Maxwell model with a power law relaxation spectrum. The effect of temperature can be modeled by an Arrhenius time-temperature superposition in the temperature range 25-100°C. Thus, we obtain a full description of the viscoelastic properties of the SiLK film that can be directly implemented in a (commercially available) Finite Element Modeling package like Marc or Ansys. Furthermore, the degree of curing of the SiLK film clearly affects the viscoelastic properties. Within the range of cure index from 0.65 to 0.98, a significant change in the relaxation modulus is observed.\u3c/p\u3

Chemical–mechanical relationship of amorphous/porous low-dielectric film materials

We have performed a series of atomic simulations, from which the chemical–mechanical relationship of the amorphous/porous silica based low-dielectric (low-k) material (SiOC:H) is obtained. The mechanical stiffness of the low-k material is a critical issue for the reliability performance of IC backend structures. Due to the amorphous nature of the low-k material, a molecular structure model is required, and we present an algorithm to generate such models. In order to understand the variation in the mechanical stiffness and density resulting from modifications to the chemical configuration, sensitivity analyses have been performed using the molecular dynamics (MD) method. Moreover, a fitting equation, based on homogenization theory, is used to represent the MD simulation results in terms of the mean characteristics of the chemical configuration. The trends indicated by the simulation results exhibit good agreement with experimental results. In addition, the simulation result shows the Young’s modulus of the SiOC:H is dominated by the concentration of basicbuilding blocks Q and T, whereas the density is influenced by all the basic building blocks