Life-time Tests of Lead-free Solder Joints on Flexible Printed Circuits

IIlyefalvi-Vitez, Z.; Balogh, Bálint; Farmer, G. Thomas; Girulska, A.; Kirkpatrick, D.

doi:10.1109/polytr.2007.4339174

Cited by 2 publications

(1 citation statement)

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“…4,5 For next-generation FPCs, PI films are expected to offer enhanced T g , reduced coefficients of thermal expansion (CTE), and lower D k and dissipation factor (D f ) at high frequencies (≥10 GHz). Traditional low-CTE PI films, such as Upilex S from Ube, Kapton from Du Pont, and Apical from Kaneka, exhibit relatively high D k and D f because of their high water/moisture uptake, 6,7 which cannot meet the stringent requirement in 5G communication applications. Hence, considerable research efforts have been aimed at improving the dielectric properties of PI films.…”

Section: Introductionmentioning

confidence: 99%

Synthesis and properties of poly(ester imide) copolymers from 3,3′,4,4′‐biphenyltetracarboxylic dianhydride, 2,2′‐bis(trifluoromethyl)benzidine, and 4‐aminophenyl‐4′‐aminobenzoate

Zheng,

Gong,

Pang

et al. 2024

J of Applied Polymer Sci

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A series of poly(ester imide) (PEsI) copolymers were synthesized using 3,3′,4,4′‐biphenyltetracarboxylic dianhydride (4,4′‐BPDA), 2,2′‐bis(trifluoromethyl)benzidine (TFMB), and 4‐aminophenyl‐4′‐aminobenzoate (APAB) as the monomers. Wide‐angle x‐ray diffraction results revealed that the average interchain distances of these polymers ranged from 4.6 to 5.7 Å, increasing with the increase of TFMB contents. PEsI‐0.3 and PEsI‐0.4 exhibited a glass transition temperature (Tg) of 445 and 455°C, respectively, while no distinctive Tg was observed for the PEsI copolymers when the APAB content was >50 mol%. The coefficients of thermal expansion (CTE) of these PEsI copolymers ranged from 3.8 to 24.2 ppm K−1, increasing with the increase of TFMB contents. The PEsI copolymers exhibited a modulus of 5.7–7.8 GPa, a tensile strength of 282–332 MPa, and an elongation‐at‐break of 10.2%–23.3%. Furthermore, these copolymers exhibited a dielectric constant of 2.53–2.76, and a low dissipation factor (Df) of 0.0026–0.0032 at 10 GHz in dry state. Because of their excellent combined properties, these PEsI copolymers are promising candidates as dielectric substrate materials for the applications in next generation flexible printed circuit boards operating at high frequencies.

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Section: Introductionmentioning

confidence: 99%