Molecular design of ultra-low-k hybrid glasses

Oliver, Mark; Dubois, Géraud; Dauskardt, R.H.

doi:10.1109/iitc.2010.5510740

Cited by 4 publications

(6 citation statements)

References 6 publications

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“…Our results are consistent with the literature, wherein the elastic properties of hybrid materials increase with density. 3,14,34 We approximated the volume of each terminal group based on each atom's van der Waals radius and show that, for increasing terminal group volume, E avg decreases (Figure 1b). This is consistent with results where increased size of terminal groups degrades the mechanical properties of hybrid molecular materials.…”

Section: Resultsmentioning

confidence: 99%

“…The equilibrated densities in our simulations are within 5% of the experimental values. Finally, the average elastic modulus for the Et-OCS model was verified using SAWs. ,, …”

Section: Methodsmentioning

confidence: 99%

“…Networks with increased network connectivity had a higher density than less connected networks. The pressure profile was chosen such that the final pressure-free density was within 5% of the experimental values. , The initial pressure was 9 GPa for the simulations and linearly decreased during the simulation until atmospheric pressure was reached. The simulation cell dimensions of the equilibrated structures varied from 4.8 to 7.2 nm.…”

Section: Methodsmentioning

confidence: 99%

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The Effects of Terminal Groups on Elastic Asymmetries in Hybrid Molecular Materials

Burg

Dauskardt

2017

J. Phys. Chem. B

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An asymmetric elastic modulus is a recently discovered and unexpected property of hybrid molecular materials that has significant implications for their underlying thermomechanical reliability. Elastic asymmetries are inherently related to terminal groups in the molecular structure, which limit network connectivity. Terminal groups sterically interact to stiffen the network in compression, while they disconnect the network and interact significantly less in tension. Here we study the importance of terminal group molecular weight and size (OH, methyl, vinyl, and phenyl) on the resulting elastic asymmetries and find that increasing the terminal group size actually leads to even larger degrees of asymmetry. As a result, we develop a molecular design criterion to predict how molecular structure affects the mechanical properties, a vital step toward integrating hybrid molecular materials into emerging nanotechnologies.

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Section: Resultsmentioning

confidence: 99%

“…The equilibrated densities in our simulations are within 5% of the experimental values. Finally, the average elastic modulus for the Et-OCS model was verified using SAWs. ,, …”

Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

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The Effects of Terminal Groups on Elastic Asymmetries in Hybrid Molecular Materials

Burg

Dauskardt

2017

J. Phys. Chem. B

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“…The ethylene‐bridged backbone provides superior mechanical properties (cf. Table 1) as compared to poly(methylsilsesquioxanes) leading to highly porous ULK films sufficiently robust to withstand integration conditions 21, 22. The film porosity and pore size distribution were determined by toluene ellipsometric porosimetry (EP) on thin films,23 using the Kelvin model.…”

Section: Resultsmentioning

confidence: 99%

Post Porosity Plasma Protection: Scaling of Efficiency with Porosity

Frot

Volksen

Purushothaman

et al. 2012

Adv Funct Materials

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Increasing the porosity of oxycarbosilane dielectrics is a key approach to lower the interconnect signal delay and thus enable manufacturing of lower power consumption and higher performance microprocessors. However, this path leads to excessive dielectric process damage as the industry adapts procedures developed for dense and microporous insulators to mesoporous materials. Currently ultralow dielectric constant (k) materials cannot be integrated at the most aggressive pitch. Here, it is reported that the post porosity plasma protection enables the mitigation of process damage across a wide range of porosity regimes. The exponential increase in plasma damage with porosity when going from microporous k = 2.4 to mesoporous k = 1.8 is shown. Using the same range of materials, the strategy allows a reduction in process damage to a constant minimal level on both blanket wafers and patterned structures. The results demonstrate how the strategy can enable the extendibility of current materials and processes to future technology nodes.

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“…Since the pressure was controlled and not the volume, networks that were more connected had a higher density than those that were less connected. The same pressure profile was used for all simulations, and was chosen such that the densities of the final pressure-free simulation cells representing the experimental glasses were within 5% of the experimentally measured densities 19,43 . The pressure decreased linearly over the course of the simulations.…”

Section: Model Connectivitymentioning

confidence: 99%

Elastic and thermal expansion asymmetry in dense molecular materials

Burg

Dauskardt

2016

Nature Mater

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The elastic modulus and coefficient of thermal expansion are fundamental properties of elastically stiff molecular materials and are assumed to be the same (symmetric) under both tension and compression loading. We show that molecular materials can have a marked asymmetric elastic modulus and coefficient of thermal expansion that are inherently related to terminal chemical groups that limit molecular network connectivity. In compression, terminal groups sterically interact to stiffen the network, whereas in tension they interact less and disconnect the network. The existence of asymmetric elastic and thermal expansion behaviour has fundamental implications for computational approaches to molecular materials modelling and practical implications on the thermomechanical strains and associated elastic stresses. We develop a design space to control the degree of elastic asymmetry in molecular materials, a vital step towards understanding their integration into device technologies.

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Molecular design of ultra-low-k hybrid glasses

Cited by 4 publications

References 6 publications

The Effects of Terminal Groups on Elastic Asymmetries in Hybrid Molecular Materials

The Effects of Terminal Groups on Elastic Asymmetries in Hybrid Molecular Materials

Post Porosity Plasma Protection: Scaling of Efficiency with Porosity

Elastic and thermal expansion asymmetry in dense molecular materials

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