Carbon-Doped Silicon Oxide Films with Hydrocarbon Network Bonds for Low-k Dielectrics: Theoretical Investigations

Tajima, Nobuo; Ohno, Takahisa; Hamada, Tomoyuki; Yoneda, Katsumi; Kondo, Seiichi; Kobayashi, Nozomu; Shinriki, Manabu; Inaishi, Yoshiaki; Miyazawa, K.; Sakota, Kaoru; Hasaka, Satoshi; Inoue, Minoru

doi:10.1143/jjap.46.5970

Cited by 27 publications

(16 citation statements)

References 16 publications

(13 reference statements)

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“…In literature, molecular dynamics (MD) methods have been used to develop atomistic models of low-k materials and the mechanical properties as well as the fracture behavior were analyzed. [37][38][39][40][41][42] H. Li and co-authors used molecular dynamics simulations to investigate the fundamental structure-property relationships of OSG low-k with a primary focus on the mass density and elastic properties. 43 To examine the role of the bridging units and terminal groups, two idealized classes of molecular models were considered that are built out of the backbone structure of amorphous silica.…”

Section: Impact Of Network Structure and Uv Radiation On Mechanical Smentioning

confidence: 99%

Mechanical Stability of Porous Low-k Dielectrics

Vanstreels

Baklanov

2014

ECS J. Solid State Sci. Technol.

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This paper reviews the mechanical and fracture properties of porous ultralow-k dielectrics with the focus on chip package interaction related issues. It is shown that the mechanical and fracture properties of porous ultralow-k dielectric films are closely linked with porosity, pore morphology, network structure and deposition technology, while their fracture properties are also sensitive to reactive species in the environment. The survivability of low-k dielectrics upon integration, package assembly and subsequent reliability tests is therefore a combination of their mechanical stability, fracture properties, the specific mechanical or thermo-mechanical load and environmental effects. For the past three decades, the semiconductor industry has been improving the performance of microelectronic devices and the functionality of advanced integrated circuits through the continuous scaling of integrated circuits and the maximization of transistor density.1 Consequently, this encourages the introduction of new materials, processes, chip designs, and packaging strategies into micro-/nano-electronic products. Among these material innovations are insulating materials with a dielectric constant (k) less than that of SiO 2 , so called low-k dielectrics. During the last 15 years, various materials and methods have been developed for fabricating low-k dielectric films, among which the plasma enhanced chemical vapor deposition (PECVD) technology of porous organosilicate glasses (OSG) is the most popular due to its better compatibility with the technological needs.2-5 The reduction in k for low-k dielectrics is being pursued through the introduction of controlled levels of porosity. However, finding a good low-k material has proven to be much more challenging than first expected due to a number of integration and reliability issues.1 Besides the need of being compatible with the different lithography, etching, stripping and cleaning processes that are used in state-of-the-art integration schemes, they must also have sufficient mechanical strength to withstand the high shear stresses as well as harsh chemical environments that are involved during the chemical mechanical polishing process without cohesive or adhesive failure occurring.6-8 On top of that, since low-k dielectrics exhibit intrinsic tensile stresses and have increased coefficients of thermal expansion compared to SiO 2 , thin film cracking and adhesion are serious thermal-mechanical reliability issues for low-k dielectric materials (Figure 1). 9,10 Thermo-mechanical deformation of the package during package assembly and subsequent reliability tests can induce large local stresses that can initiate and propagate cohesive and/or adhesive cracks in different back-end of line (BEOL) layers.11 Therefore, a careful characterization of the mechanical integrity of potential new low-k candidates is required to integrate these new materials and Cu interconnects and to assure reliability during chip packaging and under field conditions. In the microelectronics industry, the elas...

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Section: Impact Of Network Structure and Uv Radiation On Mechanical Smentioning

confidence: 99%

Mechanical Stability of Porous Low-k Dielectrics

Vanstreels

Baklanov

2014

ECS J. Solid State Sci. Technol.

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“…Note also that min-cut data for Et-OCS and Et-OCS(Me) fall along a similar trend (as with the bulk two-dimensional square lattice, the EMA provides only an approximation for similar networks. The square, (3,4,6,4), and (3,6,3,6) two-dimensional Archimedean lattices all have a coordination number of four but the bond percolation thresholds of these lattices are 0.5000, 0.5248, [ 30 ] and 0.5244, [ 31 ] respectively. The accuracy of the EMA in predicting the min-cut and fracture energy scaling for hybrid glasses means that remarkably, the fracture energy scaling with connectivity for amorphous, three-dimensional hybrid glasses can be well predicted to fi rst order by modeling the glass network as a square lattice of Si atoms.…”

Section: Cohesive Fracturementioning

confidence: 99%

“…[ 2 ] Unlike existing methods for generating model hybrid glasses, [3][4][5] ours does not defi ne the network topology prior to structural relaxation. Another advanced feature of our approach is the ability to generate hybrid glasses with well-controlled network connectivity.…”

Section: Introductionmentioning

confidence: 99%

Molecular Origins of the Mechanical Behavior of Hybrid Glasses

Oliver

Dubois

Sherwood

et al. 2010

Adv Funct Materials

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Hybrid organic-inorganic glasses exhibit unique electro-optical properties along with excellent thermal stability. Their inherently mechanically fragile nature, however, which derives from the oxide component of the hybrid glass network together with the presence of terminal groups that reduce network connectivity, remains a fundamental challenge for their integration in nanoscience and energy technologies. We report on a combined synthesis and computational strategy to elucidate the effect of molecular structure on mechanical properties of hybrid glass fi lms. We fi rst demonstrate the importance of rigidity percolation to elastic behavior. Secondly, using a novel application of graph theory, we reveal the complex 3-D fracture path at the molecular scale and show that fracture energy in brittle hybrid glasses is fundamentally governed by the bond percolation properties of the network. The computational tools and scaling laws presented provide a robust predictive capability for guiding precursor selection and molecular network design of advanced hybrid organic-inorganic materials.

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“…The results suggest that the Si–C 2 H 4 –Si network structure is the most promising to realize good barrier performance and a low k . Based on these strategies, we therefore developed four precursors (figure 1) for PECVD SiCH films to control network structure: isobutyl trimethylsilane (iBTMS), diisobutyl dimethylsilane (DiBDMS), 5-silaspiro[4,4]nonane (SSN) and 1,1-divinylsilacyclopentane (DVScP) [17]. …”

Section: Introductionmentioning

confidence: 99%

Material design of plasma-enhanced chemical vapour deposition SiCH films for low-kcap layers in the further scaling of ultra-large-scale integrated devices-Cu interconnects

Shimizu

Nagano²,

Uedono

et al. 2013

Science and Technology of Advanced Materials

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Cap layers for Cu interconnects in ultra-large-scale integrated devices (ULSIs), with a low dielectric constant (k-value) and strong barrier properties against Cu and moisture diffusion, are required for the future further scaling of ULSIs. There is a trade-off, however, between reducing the k-value and maintaining strong barrier properties. Using quantum mechanical simulations and other theoretical computations, we have designed ideal dielectrics: SiCH films with Si–C2H4–Si networks. Such films were estimated to have low porosity and low k; thus they are the key to realizing a cap layer with a low k and strong barrier properties against diffusion. For fabricating these ideal SiCH films, we designed four novel precursors: isobutyl trimethylsilane, diisobutyl dimethylsilane, 1, 1-divinylsilacyclopentane and 5-silaspiro [4,4] noname, based on quantum chemical calculations, because such fabrication is difficult by controlling only the process conditions in plasma-enhanced chemical vapor deposition (PECVD) using conventional precursors. We demonstrated that SiCH films prepared using these newly designed precursors had large amounts of Si–C2H4–Si networks and strong barrier properties. The pore structure of these films was then analyzed by positron annihilation spectroscopy, revealing that these SiCH films actually had low porosity, as we designed. These results validate our material and precursor design concepts for developing a PECVD process capable of fabricating a low-k cap layer.

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Carbon-Doped Silicon Oxide Films with Hydrocarbon Network Bonds for Low-k Dielectrics: Theoretical Investigations

Cited by 27 publications

References 16 publications

Mechanical Stability of Porous Low-k Dielectrics

Mechanical Stability of Porous Low-k Dielectrics

Molecular Origins of the Mechanical Behavior of Hybrid Glasses

Material design of plasma-enhanced chemical vapour deposition SiCH films for low-kcap layers in the further scaling of ultra-large-scale integrated devices-Cu interconnects

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