Effect of organic/inorganic coating on moisture diffusion in a chip-on-board package with globtop

Abstract

The moisture diffusion in globtop material for a chip-on-board (COB) package coated with SiN x and silicone, respectively, or coated with SiN x plus silicone were measured by embedding a humidity sensor in the globtop and recording the capacitive change in three different temperature/humidity environments. The experimental results were simulated by Fick's diffusion law with finiteelement method modeling. The moisture diffusion coefficients and activation energies were calculated to quantitatively compare the moisture-resistance effects of different coatings. For example, at 85°C/85% RH, the moisture diffusion coefficients for the uncoated reference, SiN x -coated, silicone-coated, and silicone/SiN x double-layered coated samples are 1E-5, 0.8E-5, 0.7E-5, and 0.2E-5 mm 2 /s, respectively. The experimental and simulation results show that double-layered coating with silicone/SiN x has excellent moisture-resistance properties because it not only smoothes the steps on a printed circuit board (PCB) but also keeps the good moisture resistance of the inorganic films.

Diffusion of atmospheric gases into barrier-layer sealed organic light emitting diodes

“…Their values, in the range of 10 −8 -10 −7 cm 2 / s, are similar to the diffusion coefficient of water in silicone polymer ͑ϳ2 ϫ 10 −7 cm 2 / s at 70°C and 85% relative humidity͒. 12 We infer that the interface between the barrier layer and the glass substrate has the character of a polymer. Because the preceding paragraph suggests that D x Х D y , we estimate the lag time for top-down diffusion, t ᐉ,y Х ᐉ y 2 / 6D x , to be of the order of 1 s, which is too short for observation in our test.…”

“…11 Even lower values of ϳ10 −6 g / ͑m 2 day͒ reported for multilayer barriers 13,14 appear to reflect transient, not-yet steady state, diffusion. 12 Substitution of D x into Eq. ͑2͒ shows that t ᐉ,x and ͑−dA OLED / dt͒ should be reciprocal, that is, the longer the lag time, the smaller the rate of OLED darkening that follows.…”

Polybenzoxazole Nanofiber-Reinforced Moisture-Responsive Soft Actuators

“…As shown by this example, the actuator-based curtains can be potentially applied as smart moisture-proof devices for the storage of the materials and devices that are susceptible to moisture in both warehouse and outdoor. The stored objects may include medicament, gunpowder, military equipment, electronic equipment, and so forth 56, 57 . Upon the environmental humidity increasing, the smart curtains can not only shut down and shield the goods and materials, but also supply a signal to conservators for taking measures in time.

Figure 7Moisture-responsive performance of a smart curtain based on the PBONF-reinforced CNT/PVA bilayer actuators.

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