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 21 publications

(4 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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“…A previous study [5] presented EMC materials for mid-power white light LEDs for lighting applications. It was found that hygroscopic strain and water content had a linear relation, and that water adsorption would cause permanent damage to phosphor silicone.…”

Section: Introductionmentioning

confidence: 99%

Lumen Maintenance of Ternary Ag-Alloy Wire Bonded LED Package after Reliability Tests

Yuan

Chuang

2020

MSF

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In this investigation, ternary Ag-alloy wires were doped with different Pd and Au concentrations, and each wire was encapsulated in an LED package. The static and dynamic reliability were tested, and the lumen maintenance performance was examined. The static reliability tests included the sulfur test, LTSL, HTSL, and WHTSL. According to the sulfur test data, higher Pd and Au contents led to better lumen maintenance. Furthermore, the bonding wire of the LED with better lumen maintenance in the sulfur test had higher electrical resistance. The brightness decay rate of the white light LEDs was low in low-and high-temperature environments, but it was significantly higher after the WHTSL test. The dynamic reliability test after 1,000 hours of HTOL and WHTOL showed that the lumen maintenance improved with higher Pd and Au contents, indicating that doping Ag-alloy wires with sufficient amounts of Pd and Au can retard degradation due to thermal and humidity aging and oxidation reaction. Therefore, ternary Ag-Pd-Au alloy wires produced with specific drawing and annealing processes are suitable for application to mid-power white light LEDs.

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“…The shear strength data for both Au and Cu wire on Al bonding pads at 500 hours showed a decreasing trend. Ibrahim Khalilullah et al [8] pointed out that in silicone and EMC materials of mid-power white light LEDs for lighting applications, hygroscopic strain and water content have a linear relation, and the water adsorption will cause permanent damage to phosphor silicone. Huang et al [9] also conducted a WHTOL experiment on EMC LEDs and discussed the luminous flux decay, color deviation and electrical characteristics.…”

Section: Introductionmentioning

confidence: 99%

Luminous Efficiency of Pd-Doped Ag-Alloy Wire Bonded LED Package after Reliability Tests

Yuan

Chuang

2019

MSF

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In this study, binary Ag-alloy wires were doped with different Pd concentrations, and each wire was encapsulated in an LED package. The initial optical characteristics were tested, and reliability was tested with the high temperature storage life (HTSL), high temperature operating life (HTOL) and wet high temperature operating life (WHTOL). The luminous efficiency of the Ag-alloy wire LED package was about 2% higher than that of the Au wire package, but the addition of 6% Pd to the Ag-alloy wire decreased the luminous efficiency to close to that of the Au-wire LED package. This was due to the high reflectivity of silver in the blue wavelength region, as compared to the low reflectivity of palladium. After 1,000 hours of HTOL and WHTOL, the results showed that the performance of luminous flux maintenance increased with increasing Pd content, indicating that Ag-alloy wires doped with a sufficient amount of Pd can inhibit degradation due to oxidation reaction and thermal and humidity aging. Therefore, binary Ag-Pd alloy wires produced with specific drawing and annealing processes are suitable for mid-power white light LEDs in lighting applications.

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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 21 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

Lumen Maintenance of Ternary Ag-Alloy Wire Bonded LED Package after Reliability Tests

Luminous Efficiency of Pd-Doped Ag-Alloy Wire Bonded LED Package after Reliability Tests

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