Preparation of low density poly(methylsilsesquioxane)s for LSI interlayer dielectrics with low dielectric constant. Fabrication of Ångstrom size pores prepared by baking trifluoropropylsilyl copolymers

Mikoshiba, Satoshi; Hayase, Shuzi

doi:10.1039/a807068g

Cited by 71 publications

(44 citation statements)

References 24 publications

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“…[5] One of the approaches that we employed for producing porous films utilizes a blend of a curable resin with a removable pore generator (porogen). Solvents, [6] thermally labile small substituents, [7,8] block copolymers, [9] small molecules such as hyperbranched polycaprolactones, [10,11] and surfactants [12] are known to serve as porogens. The porogen leaves pores following its thermal decomposition, ultimately forming porous solid films.…”

Section: Introductionmentioning

confidence: 99%

Nanoporous Low Dielectric Cyclosiloxane Bearing Polysilsesquioxane Thin Films Templated by Poly(ε‐caprolactone)

Hyeon-Lee¹,

Lyu²,

Lee³

et al. 2004

Macro Materials & Eng

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Summary: Dielectric cyclosiloxane bearing polysilsesquioxanes (CS‐PSSQs) were prepared by acid catalyzed polymerization using 2,4,6,8‐tetramethyl‐2,4,6,8‐tetra(trimethoxysilylethyl)cyclotetrasiloxane. The molecular weight, and content of the functional end‐groups of the CS‐PSSQs were found to be dependent on the process parameters, such as the molar ratio of water and catalyst to the OCH3 group of the silane monomer, the amount of solvent, and the poly(ε‐caprolactone) (PCL) content, etc. Based on these CS‐PSSQ prepolymers, nanoporous organic/inorganic hybrid thin films were fabricated by spin‐coating mixtures of these prepolymers with star‐shaped PCL on the silicon substrate, and subsequently heating them at 150 and 250 °C for 1 minute each and then at 420 °C for 1 hour. A dielectric constant as low as 2.28 was achieved for the nanoporous PCL/CS‐PSSQ (3:7 v/v) film, along with low moisture absorption in ambient and water conditions, primarily due to the presence of hydrophobic moieties such as ethylene and methyl groups of the polymer and nano‐sized hydrophobic pores inside the matrix, resulting in the film having stable dielectric properties. Moreover, the PCL/CS‐PSSQ (3:7 v/v) nanohybrid film revealed a nanoporous structure containing ca. 1.52 nm of average‐sized mesopores, as measured by the N2 adsorption method. The CS‐PSSQ‐only film showed high mechanical strengths having an elastic modulus and hardness of 6.64 and 0.88 GPa, respectively, for the 7 500 Å thick film and 2.41 and 0.38 GPa, respectively, for the PCL/CS‐PSSQ (3:7 v/v) film. In addition, the crack velocity of the CS‐PSSQ‐only film was found to be ca. 10−11 m · s−1 in ambient conditions and an aqueous environment, probably due to the enhanced hydrophobicity and mechanical toughness of the incorporated methyl group, siloxane unit and ethylene moieties in the polymer matrix. magnified image

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Section: Introductionmentioning

confidence: 99%

Nanoporous Low Dielectric Cyclosiloxane Bearing Polysilsesquioxane Thin Films Templated by Poly(ε‐caprolactone)

Hyeon-Lee¹,

Lyu²,

Lee³

et al. 2004

Macro Materials & Eng

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“…For example, trifluoropropyltrimethoxysilane has a thermally labile trifluoropropyl group, which leaves a pore on thermal decomposition and leads to low density materials. [22] In addition to low dielectric constant, a dielectric thin film should have a good crack resistance and mechanical properties. The basic characteristics such as microstructures and molecular weight of the polymers may be closely associated with thin film properties.…”

Section: Introductionmentioning

confidence: 99%

Synthesis of Poly(methyl‐co‐trifluoropropyl)silsesquioxanes and Their Thin Films for Low Dielectric Application

Hyeon-Lee¹,

Kim²,

Min³

et al. 2003

Macro Materials & Eng

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Poly(methyl‐co‐trifluoropropyl)silsesquioxanes (P(M‐co‐TFP)SSQs) were prepared using methyltrimethoxysilane (MTMS) and trifluoropropyltrimethoxysilane (TFPTMS). The molecular weight, microstructure of the copolymers and properties of their thin films have been changed by adjusting reaction parameters such as the molar ratio of water to silane, the molar ratio of catalyst to silane, reaction time, solvent content, and temperature. The refractive index of the copolymer thin film decreased from 1.404 to ca. 1.348 as curing temperature was increased to 420 °C. The dielectric constant of the film decreased with an increase of the molecular weight of the copolymer, and the lowest dielectric constant obtained was ca. 2.2. Hardness and elastic modulus of the thin films were 0.7 and 5 GPa, respectively. Crack velocity was measured to be 10−11 m/s at the film thickness of around 0.9 μm under aqueous environment.magnified image

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“…1 The most common process for the preparation of silsesquioxane materials is a sol-gel method using the corresponding silicone monomers. 2,3 However, for complete condensation into a film, this process requires thermal curing at high temperatures exceeding 200 1C. Such high curing temperatures are not suitable for application of film coatings onto common organic materials.…”

Section: Introductionmentioning

confidence: 99%

“…[4][5][6][7] Polyhedral oligomeric silsesquioxane compounds with well-defined cube-like structures, denoted (RSiO 3/2 ) 8 , have been extensively researched as the nanoscale building blocks of organic-inorganic hybrid materials. 3 One way of using POSS compounds is the direct cross-linking of POSS units with small organic molecules to form three-dimensional networks. 8,9 However, optically transparent films of a single POSS compound are rarely formed without cross-linking reagents because of their high symmetry and crystallinity.…”

Section: Introductionmentioning

confidence: 99%

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Syntheses and properties of star- and dumbbell-shaped POSS derivatives containing isobutyl groups

Araki

Naka

2011

Polym J

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Dumbbell-shaped isobutyl-substituted C2-linked polyhedral oligomeric silsesquioxane (POSS) ((1,2-bis(heptaisobutyl-T8-silsesquioxy)ethane) IBDE), C3-linked POSS ((1,3-bis(heptaisobutyl-T8-silsesquioxy)propane) IBDP) and C6-linked POSS ((1,6-bis(heptaisobutyl-T8-silsesquioxy)hexane) IBDH) were prepared by corner capping of heptaisobutyltricycloheptasiloxane trisilanol (IB7-OH) with 1,2-bis(trichlorosilyl)ethane, 1,3-bis(trichlorosilyl)propane and 1,6-bis(trichlorosilyl)hexane, respectively. The star-shaped POSS derivative ((octakis[3-(heptaisobutyl-T8-silsesquioxy) propyldimethylsiloxy]-Q8-silsesquioxane) 9POSIB) was prepared by hydrosilylation of heptaisobutylallyl-T8-silsesquioxane (IB7A1) and octadimethylsiloxy-Q8-silsesquioxane using Karstedt's catalyst. The star and dumbbell structures of the obtained compounds were confirmed by 1 H-, 13 C-and 29 Si-nuclear magnetic resonance and matrix-assisted laser desorption ionization time-of-flight mass spectrometry analyses. With spin coating and subsequent baking at 120 1C, the star-shaped POSS compound formed an optical transparent film, but all of the dumbbellshaped POSS compounds formed opaque whitish films. The refractive index of the transparent film was 1.4567, which was higher than that of a corresponding random silsesquioxane. 9POSIB showed significantly higher thermal stability than did the dumbbell-shaped POSS compounds. Thermogravimetric analysis of the star-shaped POSS derivative showed a clear baseline shift at 24 1C, indicative of the glass-transition temperature. However, IBDE, IBDP and IBDH showed no clear baseline shift. The melting points of IBDE, IBDP, IBDH and 9POSIB were observed at 231, 231, 239 and 96 1C, respectively. The lower melting point and appearance of the glass-transition point in 9POSIB suggested its lower crystallinity, which promotes the formation of a transparent film. Polymer Journal (2012) 44, 340-346; doi:10.1038/pj.2011.133; published online 21 December 2011Keywords: dumbbell shaped; film formability; POSS; star shaped INTRODUCTION Silsesquioxanes, hybrid polymer materials consisting of organic substituents and inorganic backbones, have attracted widespread interest because of their excellent thermal, mechanical, optical and electrical properties. 1 The most common process for the preparation of silsesquioxane materials is a sol-gel method using the corresponding silicone monomers. 2,3 However, for complete condensation into a film, this process requires thermal curing at high temperatures exceeding 200 1C. Such high curing temperatures are not suitable for application of film coatings onto common organic materials. To develop lower-temperature processable materials based on silsesquioxanes, structurally well-defined ladder-type silsesquioxanes and polyhedral oligomeric silsesquioxanes (POSSs) have been considered as attractive candidates. [4][5][6][7] Polyhedral oligomeric silsesquioxane compounds with well-defined cube-like structures, denoted (RSiO 3/2 ) 8 , have been extensively researched as the nanoscale building blocks ...

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Preparation of low density poly(methylsilsesquioxane)s for LSI interlayer dielectrics with low dielectric constant. Fabrication of Ångstrom size pores prepared by baking trifluoropropylsilyl copolymers

Cited by 71 publications

References 24 publications

Nanoporous Low Dielectric Cyclosiloxane Bearing Polysilsesquioxane Thin Films Templated by Poly(ε‐caprolactone)

Nanoporous Low Dielectric Cyclosiloxane Bearing Polysilsesquioxane Thin Films Templated by Poly(ε‐caprolactone)

Synthesis of Poly(methyl‐co‐trifluoropropyl)silsesquioxanes and Their Thin Films for Low Dielectric Application

Syntheses and properties of star- and dumbbell-shaped POSS derivatives containing isobutyl groups

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