DocumentCode :
59319
Title :
Optimal Material Properties of Molding Compounds for MEMS Package
Author :
Yeonsung Kim ; Hohyung Lee ; Xin Zhang ; Seungbae Park
Author_Institution :
Dept. of Mech. Eng., State Univ. of New York at Binghamton, Binghamton, NY, USA
Volume :
4
Issue :
10
fYear :
2014
fDate :
Oct. 2014
Firstpage :
1589
Lastpage :
1597
Abstract :
In this paper, an optimization study of molding compounds for a microelectromechanical systems (MEMS) sensor package has been performed. A comprehensive finite element analysis model was established for the MEMS sensor package to assess the stresses and deformations when the package was subjected to temperature loading. A series of stress relaxation tests were performed to characterize the viscoelastic material properties of a molding compound over temperature with dynamic mechanical analysis. A master curve for the molding compound was constructed by a proper shift function and the Prony pairs were obtained by curve fitting to be implemented in the simulation. To validate the simulation result, the thermal behavior of the MEMS package was measured. The digital image correlation technique was employed to observe the real-time deformation of the package exposed to temperature loading. The out-of-plane deformation of the package was compared with the simulation result. With the validated simulation model, the optimization study was conducted. By the process simulation, it has been shown that most of the thermal stress on the MEMS sensor chip was generated during the cooling process. Thus, a detailed cooling profile was developed by the transient heat analysis and applied to the parametric study. The modulus, coefficient of thermal expansion (CTE), and glass transition temperature (Tg) of molding compound were investigated. The result shows that a low modulus, low CTE, and low Tg molding compound can minimize the thermal stress on MEMS sensor die.
Keywords :
cooling; curve fitting; deformation; electronics packaging; finite element analysis; microsensors; moulding; optimisation; stress measurement; stress relaxation; temperature sensors; thermal expansion measurement; thermal stresses; thermal variables measurement; viscoelasticity; CTE; MEMS sensor package; coefficient of thermal expansion; cooling process; curve fitting; digital image correlation technique; dynamic mechanical analysis; finite element analysis model; glass transition temperature; master curve; microelectromechanical systems sensor package; molding compound; optimal material property; optimization; out-of-plane deformation; process simulation; prony pair; stress relaxation testing; temperature loading; thermal behavior; thermal stress; transient heat analysis; viscoelastic material property; Compounds; Micromechanical devices; Strain; Stress; Temperature; Temperature measurement; Temperature sensors; Master curve; microelectromechanical systems (MEMS); molding compound; relaxation modulus; viscoelasticity;
fLanguage :
English
Journal_Title :
Components, Packaging and Manufacturing Technology, IEEE Transactions on
Publisher :
ieee
ISSN :
2156-3950
Type :
jour
DOI :
10.1109/TCPMT.2014.2351574
Filename :
6894137
Link To Document :
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