| Moisture-resistant coating technology is of great importance for high reliability electronic modules applied in extremely high-temperature and high-humidity environment. In this thesis, an organic/inorganic dual-layer moisture-resistant coating technology including the material selection, process optimization and moisture-resistant ability was studied by both experiment and simulation. Then the dual-layer coating technology was applied in the research on the moisture sensitivity level of advanced flipchip on board (FCOB) packaging. The properties and moisture-resistant abilities of plasma enhanced chemical vapor deposition (PECVD) SiNx films deposited at near room-temperature were also studied for the application in organic light emitting devices (OLED) packaging, which need a barrier layer against moisture and oxygen deposited at less than 55.A silicone/ SiNx dual-layer structure was used by selection on various organic conformal coatings and inorganic films. A layer of silicone coating with smooth surface and without bubbles was obtained by optimization of coating process. PECVD SiNx films with good moisture-resistant ability, step coverage, uniformity on large area, stability under high humidity environment and thermal shock were deposited by optimization of deposition parameters. Then a silicone/SiNx dual-layer structure with a good smooth surface was obtained by process optimization of the SiNx deposition on silicone surface.Humidity sensors are wire-bonded to FR4 laminate boards as Chip On Board (COB) and packaged with epoxy-based globtop. The moisture diffusions in globtop material of uncoated, SiNx-coated, silicone-coated and silicone plus SiNx dual-coated samples were investigated at three different environments 70 /85%RH, 85/85%RH and 95/85%RH. The experimental results were simulated by Finite Element Method according to Fick's bulk diffusion law.The moisture diffusion coefficients, diffusion activated energies and time-dependant distributions of moisture concentration in COB packages were calculated. The moisture-resistances of SiNx-coating and silicone-coating are similar and not good enough, which is due to poor step coverage of SiNx and polymer structure of silicone. The excellent moisture-resistance can be found in silicone plus SiNx dual-coated sample. This may be contributed to the fact that thesilicone coating not only blocks the moisture ingress but also smooths the globtop step, therefore SiNx films can be deposited compactly.The research results of organic/inorganic dual-layer coating technology were applied in the research on FCOB moisture sensitivity level. The moisture effect on FCOB reliability was studied for uncoated, SiNx-coated, silicone-coated and silicone plus SiNx dual-coated samples. The conclusions can be listed below.The moisture ingress may gradually degrade the adhesion of interface between Si-chip and epoxy-based material, but the moisture effect on FCOB reliability is not significant. A small amount of moisture absorbed in underfill material can not lead to delamination of interface between Si-chip and underfill.The temperature (even high temperature at 240) effect on FCOB reliability is not significant. The silicone plus SiN dual-coated samples can pass JEDEC moisture sensitivity level 1.The combined effect of moisture and temperature (especially high temperature) can heavily damage the reliability of FCOB. The uncoated, SiN-coated and silicone-coated samples all failed in JEDEC moisture sensitivity level 1 qualification.Even not at very high temperature, FCOB samples with extremely high moisture concentration may show delamination. After 1000h at 85/85%RH environment the uncoated samples contained extremely high concentration moisture. Therefore after the following thermal shock with a high temperature at 125, a small area of delamination can be observed.PECVD SiN films' properties such as density, refractive index, composition and bonding configuration are varied with the substrate temperature and RF power. With increasing substrate temperature from 20 to...
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