Electrical properties of silica-polyimide composite dielectric thin films prepared via sol-gel reaction and thermal imidization

Kim, Y.; Kang, Eun Kyeong; Kwon, Young−Soo; Cho, W.J.; Cho, C.; Chang, Ming; Ree, Moonhor; Chang, Taihyun; Ha, Cong-Tu

doi:10.1016/s0379-6779(97)80291-3

Cited by 53 publications

(33 citation statements)

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“…[16] The dielectric constants of both the silica particle/PI composites and the CNT/polymer composites increase with the increase of inclusion content. [13,18] These results reveal that the dielectric behavior of the ST/PI composite is clearly different from materials reported previously, and the incorporation of silica tubes is a promising approach to reduce the dielectric constant.…”

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confidence: 55%

Novel Silica Tube/Polyimide Composite Films with Variable Low Dielectric Constant

Zhang

et al. 2005

Advanced Materials

121

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Since the first transmission electron microscopy (TEM) image of carbon nanotubes (CNTs) was reported, [1] much attention has been paid to their potential applications. These applications include chemical probes, nanoprobes, sensors, hydrogen storage devices, and displays. [2±5] Recently, many new tubular nanomaterials, such as SiO 2 , [6,7] V 2 O 5 , [8] and MoS 2 , [9] have been reported. These tubular materials have large specific surface areas and hollow structures, which make them potentially suitable for applications as catalysts, storage devices, and templates to grow other nanosized materials. One of the new potential applications is to incorporate the hollow tubes into a polymer matrix to reduce the total dielectric constant of the composite, which is very important in the microelectronic industry. Polyimide (PI) has been widely used as an interlayer dielectric in microelectronic devices, as electrical insulation of conventional appliances, and for other industrial applications because of its high-temperature durability, good mechanical properties, excellent chemical and thermal stabilities, low thermal expansion coefficient, and low dielectric constant (e).[10±12]Another attractive feature of PI is that it can be filled with certain low-dielectric-constant material to adjust its dielectric constant without greatly effecting its mechanical strength and chemical stability. Recently, silica particle/PI composite films have been prepared via a sol±gel process. Its dielectric constant, however, monotonically increased with the content of silica particles.[13±15] This does not meet the requirement for low dielectric constant in the microelectronic industry. Although the layered-silicate/PI nanocomposites display much lower water absorption, substantially lower leakage-current density, and a lower thermal expansion coefficient than those of pristine PI, the drawback is that the dielectric constant of the doped composite is larger than that of the matrix PI, and also increases with the content of inclusion. [16] Other inclusion materials, such as alumina (dielectric constant e = 10), titania (e = 100), and CNTs (conductive), [17,18] will lead to a significant increase of dielectric constant of the composites. In this study, silica tubes (STs) were synthesized by self-assembly, and the ST/PI composite films were then prepared by mixing the STs and PI precursors in a solution of N,N-dimethylacetamide (DMAc) under ultrasonic agitation. The ST contents in the composites are 0, 1, 3, 10, and 20 wt.-%, respectively. The mixed solutions were polymerized in situ and then cast onto a flat glass plate. The mixture was thermally imidized from 50 to 300 C to form ST/PI composite films. The morphology of the silica tubes derived from the template selfassembly was characterized using scanning electron microscopy (SEM) and TEM. The dielectric properties of the composites were characterized with a temperature ranging from ±150 to 150 C and a frequency of 1 kHz to 1 MHz. The mechanism for the reduction of the dielectric constan...

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confidence: 55%

Novel Silica Tube/Polyimide Composite Films with Variable Low Dielectric Constant

Zhang

et al. 2005

Advanced Materials

121

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“…Recent investigations of optical, dielectric and electrical properties of advanced polymer nanocomposites filled with inorganic nanofiller exhibited increase or decrease in their observed values with the filler nanoparticles concentration [10,12].…”

Section: Resultsmentioning

confidence: 99%

“…The applications of the polyimide-silica nanostructured systems have been extended to opto-electronic and photonic fields, nonlinear optics, optical guides and photorefractive materials in addition to aerospace and microelectronics devices [12,13].…”

Section: Introductionmentioning

confidence: 99%

Electrical and thermal properties of polyimide/silica nanocomposite

Tommalieh

Zihlif

Ragosta

2011

Journal of Experimental Nanoscience

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The electrical and thermal properties of thin films of polyimide/silica nanocomposites prepared via sol-gel process were studied as a function of nanosilica particles content, temperature and applied field frequency. It was found that the dielectric constant and dielectric loss of the nanocomposites decrease with both the frequency and the nanosilica content, while increase with temperature. The AC-conductivity measured in frequency range 200 kHz-1.5 MHz decreases with the filler concentration and increases with increasing temperature. For the (25 wt%) nanocomposite, it was found that the AC-conductivity increases with temperature, and the Cole-Cole plots showed that the calculated activation energy and relaxation time decrease with temperature. The observed thermal conductivity increases gently with temperature. The empirical universal law was used to fit the observed electrical data under the measuring conditions.

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“…These hybrids showed improved dielectric and optical properties, whereas the interfacial stress and the thermal expansion coefficient were found considerably reduced owing to the sil- ica aerogels despite their low thermal expansivity. Kim et al [60] studied the effects of TEOS content on the dielectric properties of PI hybrids using two type of soluble precursors chemically convertible to PI [poly(p-phenylene biphenyltetracarboxamic acid) (BPDA-PDA) and BPDA-PDA diethyl ester (BPDA-PDA ES)]. It was found that BPDA-PDA gave homogeneous nanocomposite films, whereas heterogeneous micron sized hybrids were generated with the BPDA-PDA ES precursor.…”

Section: Applicationsmentioning

confidence: 99%

Polyimide/silica hybrids via the sol-gel route: High performance materials for the new technological challenges

Ragosta¹,

Musto²

2009

Express Polym. Lett.

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Abstract. The present review article describes in detail the state-of-the-art of organic-inorganic hybrid materials based on polyimide/silica components. The article is divided in three parts. In the first the basic processing route for the preparation of these systems is described, i.e. the sol-gel technique, along with the strategies developed to control the final morphology. In the second part the curing characteristics, the dynamic-mechanical and the mechanical and fracture properties of hybrids with different morphologies are reviewed. Finally, the more technologically relevant applications devised for these high performance materials are discussed. : nanocomposites, hybrid materials, polyimide, silica, sol-gel eXPRESS Polymer Letters Vol.3, No.7 (2009) [413][414][415][416][417][418][419][420][421][422][423][424][425][426][427][428] Available online at www.expresspolymlett.com DOI: 10.3144/expresspolymlett.2009.51 or as functional materials [14] such as catalyst supports [15] and microelectronic devices [16]. The sol-gel route represents the preferred way for the synthesis of polyimide based hybrids. The classical sol-gel process consists in a two step hydrolysis-condensation reaction, starting with a metal alkoxides M(OR) 4 , typically tetraethoxisilane Si(OCH 2 CH 3 ) 4 or titanium isopropoxide Ti[OCH(CH 3 ) 2 ] 4 , to produce hydroxyl groups followed by the polycondensation of the hydroxyl groups and residual alkoxy groups to form a three-dimensional network [5,[17][18][19][20][21]. Polyimides are particularly suited for this type of process because they can be obtained from polyamic acid precursors, which are soluble in hygroscopic solvents and can, therefore, tolerate the addition of water necessary to bring about the hydrolysis of the metal alkoxide. Moreover, the outstanding thermal stability of polyimides allows the hybrids to be post-cured at very high temperatures (300-350°C) making it possible the development of a very dense inorganic network without inducing appreciable degradation of the organic phase. Polyimide/silica hybrids made by the sol-gel technique are the subject of this review, in which the approaches used for a close control of their final morphology, the effects of the silica phase on the curing process of polyimide precursors, the dynamic-mechanical and the mechanical and fracture properties that these materials can display, and their possible applications will be presented and discussed. Keywords Processing and morphologyA typical procedure for the preparation of PI/silica hybrids via the sol-gel route, involves the following steps: i) The polyamic acid (PAA) (PI precursor) is formed by a polyaddition reaction of a dianhydride [e.g., pyromellitic anhydride (PMDA), 3,3′,4,4′-biphenyltetracarboxylic dianhydride (BPDA), or 2,2-bis(3,4-dicarboxy-phenyl)-hexafluoropropane dianhydride (6FDA)] with a diamine [e.g., 4,4′-oxydianiline (ODA), or p-phenylen diamine (PPA)] in a common solvent [e.g., dimethylacetamide (DMAc), or N-methyl pyrolidone (NMP)]. The reaction and chemical str...

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Electrical properties of silica-polyimide composite dielectric thin films prepared via sol-gel reaction and thermal imidization

Cited by 53 publications

References 2 publications

Novel Silica Tube/Polyimide Composite Films with Variable Low Dielectric Constant

Novel Silica Tube/Polyimide Composite Films with Variable Low Dielectric Constant

Electrical and thermal properties of polyimide/silica nanocomposite

Polyimide/silica hybrids via the sol-gel route: High performance materials for the new technological challenges

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