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

fYear

2003

fDate

28-30 Oct. 2003

Firstpage

392

Lastpage

395

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;

fLanguage

English

Publisher

ieee

Conference_Titel

Electronic Packaging Technology Proceedings, 2003. ICEPT 2003. Fifth International Conference on

Conference_Location

Shanghai, China

Print_ISBN

0-7803-8168-8

Type

conf

DOI

10.1109/EPTC.2003.1298768

Filename

1298768