Title :
Investigation on moisture diffusion in COB packaging [chip on board]
Author :
Huang, Weidong ; Wang, Xuhong ; Wang, Li ; Sheng, Mei ; Xu, Liqiang ; Stubhan, Frank ; Luo, Le
Author_Institution :
DaimlerChrysler SIM Technol. Co., Ltd., Shanghai, China
Abstract :
The moisture diffusion in globtop material, globtop coated with SiNx film, globtop coated with silicone and globtop coated with SiNx plus silicone were measured by humidity sensors wire-bonded on FR4 boards in three different temperature/humidity environments. The experimental results were simulated by the finite element method and Fick diffusion law. The moisture diffusion coefficients were calculated to quantitatively compare various coatings´ moisture-resistance. Our experimental and simulation results show that a double-layered coating with SiNx plus silicone has excellent moisture-resistance because it can not only smooth the steps on the PCB but also keep the good moisture-resistance of inorganic films.
Keywords :
chip-on-board packaging; conformal coatings; diffusion; encapsulation; finite element analysis; moisture; plastic packaging; silicon compounds; silicones; COB moisture diffusion coefficients; FR4 boards; Fick diffusion law; SiN; chip on board packaging; coating moisture-resistance; conformal coating; epoxy-based globtop materials; finite element method; globtop encapsulated COB; globtop material moisture diffusion; moisture ingress; plastic encapsulation; silicone; temperature/humidity environment; wire-bonded humidity sensors; Absorption; Coatings; Corrosion; Humidity measurement; Materials science and technology; Moisture measurement; Packaging; Plasma temperature; Protection; Temperature sensors;
Conference_Titel :
Electronic Packaging Technology Proceedings, 2003. ICEPT 2003. Fifth International Conference on
Conference_Location :
Shanghai, China
Print_ISBN :
0-7803-8168-8
DOI :
10.1109/EPTC.2003.1298768
