In-situ characterization of moisture absorption and hygroscopic swelling of silicone/phosphor composite film and epoxy mold compound in LED packaging

Khalilullah, Ibrahim; Reza, Talukder; Chen, Liangbiao; Placette, Mark D.; Mazumder, A. K. M. Monayem H.; Zhou, Jiang; Fan, Jiajie; Qian, Cheng; Zhang, Guoqi; Fan, Xuejun

doi:10.1016/j.microrel.2018.03.025

Cited by 20 publications

(2 citation statements)

References 15 publications

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“…Figure 3 shows the average mass increases in EMC at 85 °C/85% RH and 60 °C/60% RH. For both conditions, the weight increases were faster at the beginning of tests, but generally stabilized when the tests lasted for longer than 35 h. Although different diffusion models have been proposed for moisture diffusion [ 23 , 24 , 25 , 26 ], Fick’s law is still the most common theory used for data analysis [ 12 , 27 ], which was also employed in our study.…”

Section: Resultsmentioning

confidence: 99%

Effects of Moisture Diffusion on a System-in-Package Module by Moisture–Thermal–Mechanical-Coupled Finite Element Modeling

et al. 2022

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Epoxy molding compounds (EMCs) are commonly used in electronic products for chip encapsulation, but the moisture absorption of EMC can induce significant reliability challenges. In this study, the effects of hygrothermal conditions and structure parameters on moisture diffusion and the consequent influences (such as moisture content on die surfaces and stress distribution) on a system-in-package module have been systematically investigated by moisture–thermal–mechanical-coupled modeling. Hygroscopic tests were carried out on a new commercial EMC at 60 °C/60% RH and 85 °C/85% RH, followed by evaluations of diffusion coefficients by Fick’s law. It was found that the moisture diffusion coefficients and saturation concentrations at 85 °C/85% RH were higher than those at 60 °C/60% RH. From the modeling, it was found that the consequent maximum out-of-plane deformation and stress of the module at 85 °C/85% RH were both higher than those at 60 °C/60% RH. Influences of thicknesses of EMC and PCB on the moisture diffusion behavior have also been studied for design optimization. It was found that the maximum moisture concentration on die surfaces and resultant stress increased notably with thinner PCB, whereas the effects of EMC thickness were limited. This can be attributed to the comparison between the thicknesses of EMC and PCB and the shortest existing diffusion path within the module. These findings can provide helpful insights to the design optimization of electronic modules for hygrothermal conditions.

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Section: Resultsmentioning

confidence: 99%

Effects of Moisture Diffusion on a System-in-Package Module by Moisture–Thermal–Mechanical-Coupled Finite Element Modeling

et al. 2022

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“…Usually molding compounds are insulators and show low electric conductivity. 16 However, the conductivity may in general depend on the moisture [19][20][21] and water can be incorporated into the molding compound 22 such that the conduction properties may be influenced by the sample environment and history. As one aspect of electric conductivity, it is known that molding compounds can show a finite ionic conductivity.…”

mentioning

confidence: 99%

Pathways for Alkali Ion Transport in Mold Compounds

Motta¹,

Schäfer²,

Noll³

et al. 2020

ECS J. Solid State Sci. Technol.

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The mobility of potassium ions in a molding compound designed for electronic device insulation has been investigated by a charge attachment induced transport (CAIT) experiment. Two different transport pathways have been identified, i.) through the bulk of the sample and ii.) along boundaries of silica grains embedded in the organic components of the molding compound. The corresponding diffusion coefficients for K+ transport are DB = 1.8 × 10−21 cm2 s−1 for the bulk and DGB = 5.4 × 10−20 cm2 s−1 for the grain boundary. The effective activation energy for charge carrier transport amounts to 1.57 eV.

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Effects of humidity and phosphor on silicone/phosphor composite in white light-emitting diode package

Hoque

Bradley

Fan

et al. 2019

J Mater Sci: Mater Electron

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Silicone/phosphor composite, which serve as mechanical protection and light conversion material, is an integral part of white light-emitting diode (LED) package. In this paper, a comprehensive study is conducted to investigate the effect of humidity and phosphor on moisture absorption, hygroscopic swelling, mechanical behavior, as well as thermal properties of silicone/ phosphor composite in comparison with the pure silicone. SEM/EDAX and FTIR were performed to identify the phosphor and silicone compositions. Through moisture sorption test, it has been observed that the addition of phosphor significantly lowers the capacity of moisture absorption, but accelerates the diffusivity of moisture absorption. The hygroscopic swelling test showed that the phosphor has little effect on the swelling compared to the pure silicone sample. Both moisture absorption/desorption and hygroscopic swelling/de-swelling are reversible. Strain ramp test revealed that the phosphor enhances the stiffness of the composite. The moisture absorption, however, has negligible impact on mechanical stiffness for both pure and composite samples. Finally, thermal expansion test showed that the coefficient of thermal expansion does not change with the addition of phosphor into pure silicone.

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In-situ characterization of moisture absorption and hygroscopic swelling of silicone/phosphor composite film and epoxy mold compound in LED packaging

Cited by 20 publications

References 15 publications

Effects of Moisture Diffusion on a System-in-Package Module by Moisture–Thermal–Mechanical-Coupled Finite Element Modeling

Effects of Moisture Diffusion on a System-in-Package Module by Moisture–Thermal–Mechanical-Coupled Finite Element Modeling

Pathways for Alkali Ion Transport in Mold Compounds

Effects of humidity and phosphor on silicone/phosphor composite in white light-emitting diode package

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