Optical, thermal-strain, and water-sorption properties of plastic resins for laser-diode molding

Shuto, Y.; Sato, Hirotsugu; Fukuda, Mitsuo; Tohno, S.

doi:10.1002/(sici)1520-6432(199812)81:12<17::aid-ecjb3>3.0.co;2-h

Cited by 4 publications

(3 citation statements)

References 9 publications

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“…Shuto et al [11] found that the moisture in silicone gel (2 mm thick) saturated after approximately 2 h of humidity exposure under 85% RH and 85 • C. Using the equation in their work, we found that, for our case where the silicone gel is only 0.52 mm, the time to moisture saturation in the gel is only 8 min under the same environmental condition. In other words, the amount of moisture in the gel should be the same for LEDs with 24-and 48-h humidity exposure, and this is consistent with our experimental results in Fig.…”

Section: B Eds Analysissupporting

confidence: 53%

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Rapid Light Output Degradation of GaN-Based Packaged LED in the Early Stage of Humidity Test

Tan

Chen

et al. 2012

IEEE Trans. Device Mater. Relib.

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An initial sharp decrease in the light output of a high-power light-emitting diode is observed when it is exposed to humid condition. TGA and energy-dispersive system analyses confirm the possibility of moisture entrapment in the silicone encapsulation; moreover, the light scattering model verifies qualitatively the scattering of the light due to the entrapped moisture, and it is this scattering that renders an initial sharp drop in the light output. The finding shows the importance of pore size of the silicone gel in order to prevent such sharp decrease in the light output under a humid environment.

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Section: B Eds Analysissupporting

confidence: 53%

“…It is found that the volume fraction of water in silicone gel saturated rapidly at approximately 0.064% [11]. For the LEDs used in this work, there are two local maxima in their radiation spectrum since the white light emitted is a combination of the blue light from the die and the yellow light from the phosphor on the die.…”

Section: B Eds Analysismentioning

confidence: 82%

Rapid Light Output Degradation of GaN-Based Packaged LED in the Early Stage of Humidity Test

Tan

Chen

et al. 2012

IEEE Trans. Device Mater. Relib.

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“…Silicones are one such encapsulant material in high power LED devices which have received great consideration over epoxy resin in recent decades owing to their outstanding properties like good thermal stability, higher luminous efficiency, better transparency, good barrier properties and higher refractive index [33,34]. On the other hand, it has been proved by Shuto et al [35] that the moisture resistance of silicone is inferior than that of epoxy resin. On account of the low intermolecular interactions in the silicone network, their free volume is higher than hydrocarbons facilitating higher permeability to oxygen and water.…”

Section: Introductionmentioning

confidence: 99%

Exploring water and ion transport process at silicone/copper interfaces using in-situ electrochemical and Kelvin probe approaches

Munirathinam

Dam

Herrmann

et al. 2021

Journal of Materials Science & Technology

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In general, packaging materials which encapsulate light emitting diodes (LEDs) and microelectronic devices offer barrier protection against several environmental hazards such as water and ionic contaminants. However, these encapsulants may provide pathways for water and ionic contaminants to reach the metal/polymer interfaces and provoke local corrosion of electronics, which is a major reliability concern for polymer encapsulated LEDs and microelectronics. As the water and corrosive constituents play a crucial role in their reliability, water uptake kinetics, interfacial ion transport and delamination behaviour of silicone coated copper model system, mimicking a typical microelectronics packaging system, is explored in the present work. Electrochemical impedance spectroscopy (EIS) integrated with attenuated total reflection Fourier transform infrared (ATR-FTIR) spectroscopy studies revealed that water diffusion inside the silicone network is Fickian in nature and the evolution of the observed time constants are related to the diffusion and interfacial reactions. A decrease of impedance magnitude with time was observed in EIS measurements concurrently with water absorption bands shifting towards lower wavenumber in ATR-FTIR measurements, implying the growth of strong hydrogen bonding between water molecules and the silicone network. The estimated diffusion constant of water using the capacitance method was in the order of 7 × 10 -12 m 2 s −1 and the water absorption volume fraction was in the range of 0% to 0.30%. Scanning Kelvin probe studies elucidated the ion transport process occurring at the silicone/copper interface in a humid atmosphere. The interfacial ion transport process is controlled by the interfacial electrochemical reactions at the cathodic delamination front and the estimated average delamination rate is 0.43 mm h -1/2 . This work demonstrates that exploring ion and water transport in the silicone coating and along the silicone/copper interface is of pivotal importance as part of a detailed reliability assessment of the polymer encapsulated LEDs and microelectronics.

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Diffusion and absorption of corrosive gases in electronic encapsulants

Hillman

Castillo

Pecht

2003

Microelectronics Reliability

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Optical, thermal-strain, and water-sorption properties of plastic resins for laser-diode molding

Cited by 4 publications

References 9 publications

Rapid Light Output Degradation of GaN-Based Packaged LED in the Early Stage of Humidity Test

Rapid Light Output Degradation of GaN-Based Packaged LED in the Early Stage of Humidity Test

Exploring water and ion transport process at silicone/copper interfaces using in-situ electrochemical and Kelvin probe approaches

Diffusion and absorption of corrosive gases in electronic encapsulants

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