In Situ Observation of Water Behavior at the Surface and Buried Interface of a Low-K Dielectric Film

Abstract

Water adsorption in porous low-k dielectrics has become a significant challenge for both back-end-of-line integration and reliability. A simple method is proposed here to achieve in situ observation of water structure and water-induced structure changes at the poly(methyl silsesquioxane) (PMSQ) surface and the PMSQ/solid buried interface at the molecular level by combining sum frequency generation (SFG) vibrational spectroscopic and Fourier transform infrared (FTIR) spectroscopic studies. First, in situ SFG investigations of water uptake were performed to provide direct evidence that water diffuses predominantly along the PMSQ/solid interface rather than through the bulk. Furthermore, SFG experiments were conducted at the PMSQ/water interface to simulate water behavior at the pore inner surfaces for porous low-k materials. Water molecules were found to form strong hydrogen bonds at the PMSQ surface, while weak hydrogen bonding was observed in the bulk. However, both strongly and weakly hydrogen bonded water components were detected at the PMSQ/SiO2 buried interface. This suggests that the water structures at PMSQ/solid buried interfaces are also affected by the nature of solid substrate. Moreover, the orientation of the Si-CH3 groups at the buried interface was permanently changed by water adsorption, which might due to low flexibility of Si-CH3 groups at the buried interface. In brief, this study provides direct evidence that water molecules tend to strongly bond (chemisorbed) with low-k dielectric at pore inner surfaces and at the low-k/solid interface of porous low-k dielectrics. Therefore, water components at the surfaces, rather than the bulk, are likely more responsible for chemisorbed water related degradation of the interconnection layer. Although the method developed here was based on a model system study, we believe it should be applicable to a wide variety of low-k materials.

Role, effect, and influences of micro and nano‐fillers on various properties of polymer matrix composites for microelectronics: A review

“…Low dielectric constants materials are also equally important in the field of modern IC to minimize both cross‐talk noise and resistance capacitance delay . Recently, various methods have been introduced to develop PIs with low and ultra‐low dielectric constant materials, in particular, well‐designed organic‐inorganic hybrid materials systems have been gaining attraction significantly for microelectronics because of their utilization in ICs and also systems with pore voids or air gap were used.…”

“…In general, pristine PI is used as a polymer matrix because it has good mechanical properties, in addition to high chemical and thermal stability, but the dielectric constant ε ≈ 3.5, 74,75 and the dielectric permittivity has been several times enhanced (28.42 times, 72 26.6 times, 75 4 times, 76 Low dielectric constants materials are also equally important in the field of modern IC to minimize both cross-talk noise and resistance capacitance delay. 81 Recently, various methods have been introduced to develop PIs with low and ultra-low dielectric constant materials, 82 in particular, well-designed organic-inorganic hybrid materials systems have been gaining attraction significantly for microelectronics because of their utilization in ICs 83 and also systems with pore voids or air gap were used. Although nanotubes filled composites exhibit better property in aligned direction, in order to minimize this anisotropic behavior of the composites, mesoporous silica filler is used as smart inorganic filler, which has unique properties such as uniformly distributed mesopores, high pore volume, and very large surface areas.…”

Effect of nanoparticle localization on the rheology, morphology and toughness of nanocomposites based on poly(lactic acid)/natural rubber/nanosilica

“…[30][31][32][33] In this regard, researchers have suggested reactive compatibilization and adding block or graft copolymers. 28,[34][35][36][37] However, another compatibilization strategy has been developed recently, based on the incorporation of inorganic solid nanoparticles. [38][39][40][41][42][43][44][45] The addition of nanoparticles to a blend affects the interfacial tension as well as the viscosity ratio between phases, and subsequently morphological changes occur.…”

Influence of aliphatic polycarbonate middle block on mechanical and microstructural behaviour of triblock copolymers based on poly(l‐lactide) and polycarbonate

“…3,[9][10][11] However, neat PLA shows low elongation and tensile toughness which restricts its use in applications where toughness is required particularly for durable applications such as in automotive and electronics. 12 Approaches to overcome these limitations include blending with elastomers, 13,14 copolymerization with another rubbery polymer, [15][16][17] addition of plasticizers 18 and composite development. 19,20 Copolymerization is a simple and effective way for modifying the brittle nature of PLA with superior interfacial adhesion because of chemical bonding.…”